JP2008046256A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method capable of imparting additional information without harming the color tone of an image. <P>SOLUTION: Additional information can be imparted to an image without harming the color tone of an image by forming a first image region using a toner containing a crystallinity resin and a second image region using a toner containing no crystallinity resin, controlling a gloss or an X-ray diffraction intensity at the diffraction angle of a specified X-ray diffraction peak derived from the crystallinity resin to be different between the first image region and the second image region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method using an electrostatic image developing toner (hereinafter sometimes abbreviated as “toner”) such as an electrophotographic method, and more particularly to an image forming method for imparting additional information to an image.

  A method of forming image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic image is formed on a photoreceptor by charging and exposure processes, the electrostatic image is developed with a developer containing toner, and image information is visualized through a transfer and fixing process. The developer used here includes a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone.

  Conventionally, there is an additional data embedding technique for embedding additional information in an image. In recent years, there has been an active movement to improve security by using this additional data embedding technique for copyright protection of digital works such as still images, prevention of unauthorized copying, and ID cards.

  When the additional data embedding technique is used for a digital work, generally, image data in which additional data such as a copyright ID or a user ID is embedded as an invisible image so as not to be visually noticeable is distributed. Various measures are incorporated in the image forming apparatus in order to prevent forgery of securities and the like. As one of the methods, in order to identify the image forming device used for copying or printing, a symbol unique to the image forming device that is difficult to visually recognize is superimposed on the image information with a certain amount of modulation as an invisible image. There is technology to let you.

  When this technology is used, even if the securities are counterfeited using the image forming apparatus, the image of the forgery is read by a reader capable of extracting a specific wavelength range, and the invisible image is obtained. The symbol unique to the image forming apparatus can be read. Therefore, since the image forming apparatus used for counterfeiting can be specified by reading this symbol, an effective clue for tracking the counterfeiter can be obtained.

  Further, it is possible to check whether or not a document has been copied by detecting whether or not an invisible image is detected by using the fact that the invisible image is not copied by embedding additional information with the invisible image in the image.

For example, Patent Document 1 describes that an invisible image is formed using a toner containing a near-infrared light absorbing material. In Patent Document 1, in a region where a visible image and an invisible image overlap each other, only a visible image can be recognized even when the image forming surface is viewed from the front, but an invisible image is formed when viewed from an oblique direction. The presence of an invisible image can be confirmed without losing the quality of the visible image due to the difference in gloss between the area and the other areas, and real recognition / counterfeiting can be suppressed by visually recognizing the invisible image resulting from the difference in gloss. It is described that an effect is obtained. As the near infrared light absorbing material, inorganic material particles containing CuO and P ₂ O ₅ are exemplified. As near infrared light absorbing materials, other organic compounds such as cyanine dyes are known.

  On the other hand, Patent Document 2 describes that an image forming apparatus is provided with a partial cooling device to selectively give gloss to an image. Japanese Patent Application Laid-Open No. H10-228561 describes that gloss is imparted with a transparent toner. In these methods, gloss can be imparted to any location in the image.

JP 2003-186238 A JP 2005-128446 A JP-A-5-249724

  However, since the inorganic material particles described in Patent Document 1 or organic compounds such as cyanine dyes used as near infrared light absorbing materials have a slight absorption in the visible region, these near infrared light absorbing materials are When the toner to be included is used and the additional information is superimposed and formed as an invisible image, the color tone due to the pigment originally contained in the toner is hindered.

  Further, in the method of Patent Document 2, since gloss cannot be controlled in a binary manner, it is difficult to add additional information due to a difference in gloss. Even with the method of Patent Document 3, the gloss imparted by the transparent toner is insufficient, and it is difficult to impart additional information due to the gloss difference.

  The present invention is an image forming method capable of adding additional information to an image without impairing the color tone of the image.

  The present invention is an image forming method for adding additional information to an image, comprising: a first image area using a toner containing a crystalline resin; and a second image area using a toner not containing a crystalline resin. The additional information is formed by making the first image region and the second image region different in X-ray diffraction intensity or glossiness at a diffraction angle of a specific X-ray diffraction peak caused by the crystalline resin. Is granted.

  In the image forming method, when the X-ray diffraction intensity of a specific X-ray diffraction peak due to the crystalline resin in the first image region is X1, and the reference intensity at a predetermined diffraction angle is X2, (X1−X2) /X2≧0.1, the X-ray diffraction intensity at the diffraction angle of the specific X-ray diffraction peak in the second image region is X3, and the reference intensity at the predetermined diffraction angle is X4. It is preferable that (X3-X4) / X4 <0.1.

  In the image forming method, it is preferable that G1−G2> 5 when the glossiness in the first image area is G1 and the glossiness in the second image area is G2.

  In the image forming method, the toner that does not contain the crystalline resin preferably contains an amorphous resin.

  In the present invention, a first image area using a toner containing a crystalline resin and a second image area using a toner containing no crystalline resin are formed, and the first image area and the second image area By changing the X-ray diffraction intensity at the diffraction angle of a specific X-ray diffraction peak caused by the crystalline resin, additional information can be added to the image without hindering the color tone of the image.

  In the present invention, a first image area using a toner containing a crystalline resin and a second image area using a toner containing no crystalline resin are formed, and the first image area and the second image area Further, by making the glossiness caused by the crystalline resin different, it is possible to add additional information to the image without hindering the color tone of the image.

  Embodiments of the present invention will be described below. In this specification, “invisible image” refers to the color developability of an image in the visible light region because the toner forming the invisible image does not have color developability due to absorption of a specific wavelength in the visible light region. It means an image that cannot be recognized visually by the difference in color tone. “Visible image” means an image that can be visually recognized in the visible light region because the toner forming the visible image has color developability and gloss resulting from absorption of a specific wavelength in the visible light region. To do.

<Addition of additional information by X-ray diffraction intensity>
In the present embodiment, in an image forming method for adding additional information to an image, a first image region using a toner containing a crystalline resin and a second image region using a toner not containing a crystalline resin are formed. The first image region and the second image region are given additional information by making the X-ray diffraction intensities at the diffraction angles of specific X-ray diffraction peaks caused by the crystalline resin different. Then, the image of the first image area using the toner containing the crystalline resin or the image of the second image area using the toner not containing the crystalline resin is read by the X-ray diffraction intensity measuring device. The toner that does not contain a crystalline resin preferably contains an amorphous resin.

  Since the viscosity of the crystalline resin suddenly decreases in the temperature range above the melting point, the toner image formed by fixing the toner containing the crystalline resin retains its crystalline characteristics after being cooled after fixing. Therefore, it has high X-ray diffraction intensity. On the other hand, a toner image formed by fixing a toner that does not contain a crystalline resin does not have crystal characteristics after being cooled after fixing, and therefore has a lower X-ray diffraction intensity than the first image region. .

  In addition, the crystalline resin generally has almost no absorption in the visible light region, like the non-crystalline resin often used for toner, and therefore does not hinder the color tone of the toner image due to pigments or dyes. Therefore, when a toner containing a crystalline resin and a toner not containing a crystalline resin are used in combination, the site formed by the toner containing the crystalline resin cannot be distinguished depending on the color tone, but depending on the X-ray diffraction intensity It becomes possible to distinguish.

  In the formed image, only the portion formed by the toner containing the crystalline resin has the characteristic as a crystal, so the portion formed by the toner containing the crystalline resin by the X-ray diffractometer or the crystalline resin is not contained. A site formed by toner can be selectively read. Therefore, according to this method, additional information based on the X-ray diffraction intensity can be given to the image without hindering the color tone of the image. In addition, since the X-ray diffraction intensity is used, it is not possible to visually distinguish the region to which the additional information is given from the other region.

  In this embodiment, a first image area using a toner containing a crystalline resin and a second image area using a toner not containing a crystalline resin are formed, and additional information is given by the first image area. Alternatively, additional information may be given by the second image area. Since toner containing a crystalline resin is generally slightly inferior in chargeability, additional information is given to the first image area using the toner containing the crystalline resin from the viewpoint of reproducibility of latent images in electrophotography. Is preferred.

  Here, when the X-ray diffraction intensity of a specific X-ray diffraction peak due to the crystalline resin in the first image region is X1, and the reference intensity at a predetermined diffraction angle is X2, (X1-X2) / X2 ≧ 0.1 is preferable, and (X1−X2) /X2≧0.2 is more preferable. Further, when the X-ray diffraction intensity at the diffraction angle of the specific X-ray diffraction peak in the second image region is X3, and the reference intensity at the predetermined diffraction angle is X4, (X3-X4) / X4 < 0.1 and more preferably (X3-X4) / X4 <0.05. If the value of (X1-X2) / X2 is less than 0.1, the accuracy of reading additional information may be reduced. The larger the value of (X1-X2) / X2, the higher the accuracy of reading additional information. However, the upper limit is usually about 2 due to the thickness of the image and the accuracy of the measuring device. Moreover, as a specific X-ray diffraction peak, it is preferable to select an X-ray diffraction peak having the maximum intensity in order to improve reading accuracy. As the predetermined diffraction angle, an arbitrary diffraction angle may be selected from a region having no X-ray diffraction peak, for example, a region having an X-ray diffraction angle (2θ) of 12 ° to 17 °.

  For example, when a crystalline polyester resin as described later is used as the crystalline resin, a maximum X-ray diffraction peak appears in the vicinity of a diffraction angle 2θ = 21.5 ° in X-ray diffraction measurement. Therefore, when the crystalline polyester resin is used, the X-ray diffraction intensity of the X-ray diffraction peak near the diffraction angle 2θ = 21.5 ° caused by the crystalline polyester resin in the first image region is X5, X-ray diffraction It is preferable that (X5-X6) /X6≧0.1 and (X5-X6) /X6≧0.2 when the reference intensity at a diffraction angle 2θ = 15 ° where there is no peak is X6. Is more preferable. Further, when the X-ray diffraction intensity near the diffraction angle 2θ = 21.5 ° in the second image region is X7 and the reference intensity at the diffraction angle 2θ = 15 ° is X8, (X7−X8) / X8 <0. .1 is preferable, and (X7−X8) / X8 <0.05 is more preferable.

  Further, in order to improve the accuracy of additional information recognition based on the X-ray diffraction intensity, it is desirable that the development arrangement is such that the toner containing the crystalline resin is placed on the surface layer of the transfer target.

  The additional information reading device is not particularly limited as long as it can measure the X-ray diffraction intensity, but an X-ray diffraction intensity measuring device is optimal, for example, RAD-II C type X manufactured by Rigaku Corporation. Examples include a line diffraction intensity measuring device.

  By this method, for example, image data in which additional information such as a copyright ID and a user ID is embedded as an invisible image so as not to be visually noticeable can be used for copyright protection of digital works such as still images, prevention of unauthorized copying, and ID It can be used to prevent counterfeiting of cards, securities, etc. and enhance security. Further, it is possible to check whether or not a document has been copied by detecting whether or not an invisible image is detected by using the fact that the invisible image is not copied by embedding additional information with the invisible image in the image.

<Addition of additional information by glossiness>
In the present embodiment, in an image forming method for adding additional information to an image, a first image region using a toner containing a crystalline resin and a second image region using a toner not containing a crystalline resin are formed. Then, the additional information is given by making the glossiness caused by the crystalline resin different between the first image region and the second image region. Then, the image of the first image area using the toner containing the crystalline resin or the image of the second image area using the toner not containing the crystalline resin is read by the gloss measuring device. The toner that does not contain a crystalline resin preferably contains an amorphous resin.

  Since the viscosity of the crystalline resin rapidly decreases in the temperature range above the melting point, the toner image formed by fixing the toner containing the crystalline resin has a feature that a high gloss image can be obtained. On the other hand, a toner image formed by fixing a toner containing no crystalline resin has a lower gloss than the first image area.

  In addition, the crystalline resin generally has almost no absorption in the visible light region, like the non-crystalline resin often used for toner, and therefore does not hinder the color tone of the toner image due to pigments or dyes. Therefore, when a toner containing a crystalline resin and a toner not containing a crystalline resin are used in combination, the part formed with the toner containing the crystalline resin cannot be distinguished depending on the color tone, but it should be distinguished depending on the glossiness. Is possible.

  In the formed image, the color tone of the part formed with any toner does not change, but since the part formed with the toner containing the crystalline resin in the image is highly glossy, the gloss measuring device contains the crystalline resin. It is possible to selectively read a portion formed by the toner to be formed or a portion formed by the toner not containing the crystalline resin. Therefore, according to this method, it is possible to add additional information based on the glossiness without hindering the color tone of the image.

  Here, it is preferable that G1-G2> 5 when the glossiness in the first image region is G1 and the glossiness in the second image region is G2. If the value of G1-G2 is less than 5, the accuracy of reading additional information may be reduced. The larger the value of G1-G2, the better the accuracy of reading additional information, but the upper limit is usually 70.

  Further, when G1-G2 = 5 to 10, additional information can be read with high accuracy by the glossiness measuring apparatus, but it cannot be distinguished visually. When G1-G2 = 10-20, the additional information can be read with high accuracy by the glossiness measuring apparatus and can be recognized visually, but the accuracy is poor. When G1-G2 = 20 or more, the additional information can be read with high accuracy by the glossiness measuring apparatus, and can be distinguished with high accuracy by visual observation.

  For example, image data in which additional information such as a copyright ID and a user ID is embedded as an invisible image with G1-G2 = 5 to 10 so as not to be visually noticeable is used for copyright protection of digital works such as still images, It can be used to prevent unauthorized copying and prevent counterfeiting of ID cards, securities, etc., and enhance security. Whether the document is copied with or without the detection of the invisible image by using the fact that the invisible image with G1-G2 = 5 to 10 is embedded in the image and additional information is embedded and the invisible image is not copied. You can check if.

  In addition, in image data in which a visible image with G1-G2 = 20 or more is embedded as additional information, the additional information can be recognized in the original image. However, if the image is copied, the additional information is not copied. By using this, it is possible to check whether or not the document has been copied based on whether or not the additional information is detected.

  Thus, by controlling the value of G1-G2, which is the difference between the glossiness in the first image area and the glossiness in the second image area, additional information according to the purpose can be given.

  In this embodiment, a first image area using a toner containing a crystalline resin and a second image area using a toner not containing a crystalline resin are formed, and additional information is given by the first image area. Alternatively, additional information may be given by the second image area. Since toner containing a crystalline resin is generally slightly inferior in chargeability, additional information is given to the first image area using the toner containing the crystalline resin from the viewpoint of reproducibility of latent images in electrophotography. Is preferred.

  Further, in order to increase the accuracy of additional information recognition based on the glossiness, it is desirable that the development arrangement is such that the toner containing the crystalline resin is placed on the surface layer of the transfer target.

  The additional information reading device is not particularly limited as long as it can measure the glossiness. However, the glossiness measuring device is optimal, and examples thereof include a gloss checker IG331 manufactured by HORIBA.

<Toner for electrostatic image development>
(Binder resin)
In the present embodiment, the toner used for forming the first image region contains a crystalline resin, and the toner used for forming the second image region does not contain a crystalline resin but contains an amorphous resin. In a toner containing a crystalline resin, a shell layer may be formed by using a crystalline resin and an amorphous resin as core particles and covering with a noncrystalline resin.

  In the present embodiment, “crystallinity” of “crystalline resin” refers to having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC) of the resin or toner. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. A “clear” endothermic peak is assumed when the temperature from the onset point to the top of the endothermic peak when the temperature is raised at 10 ° C. is within 10 ° C. Further, from the viewpoint of sharp melt property, the temperature from the onset point to the peak top of the endothermic peak is preferably within 10 ° C., and more preferably within 6 ° C. Specify any point on the flat part of the baseline in the DSC curve and any point on the flat part of the falling part from the baseline, and the intersection of the tangents of the flat part between the two points is automatically set as the “onset point”. Obtained automatically by the tangent processing system. Further, the endothermic peak may show a peak having a width of 40 to 50 ° C. when the toner is used.

  “Non-crystalline resin” means that when the temperature from the onset point to the peak top of the endothermic peak exceeds 10 ° C. in the differential scanning calorimetry (DSC) of the resin or toner, or a clear endothermic peak is observed. It refers to a resin that cannot be used. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. When the temperature from the onset point to the peak top of the endothermic peak when the temperature is raised at 10 ° C exceeds 10 ° C., or when no clear endothermic peak is observed, it is assumed to be “non-crystalline”. Further, the temperature from the onset point to the peak top of the endothermic peak preferably exceeds 12 ° C., and more preferably no clear endothermic peak is observed. The method for obtaining the “onset point” in the DSC curve is the same as in the case of the “crystalline resin”.

  Here, in order to enable recognition of the additional information, in the toner used for forming the first image region, the content of the crystalline resin is 15 wt% to 40 wt% with respect to the total weight of the binder resin. The range is preferable, and the range of 20% by weight to 30% by weight is more preferable. In the toner used for forming the second image region, the content of the crystalline resin is preferably 0% by weight to 5% by weight, and preferably 0% by weight to 2% by weight with respect to the total weight of the binder resin. More preferably. That is, the “toner not containing a crystalline resin” in this specification includes a toner whose content of the crystalline resin is 0% by weight to 5% by weight with respect to the total weight of the binder resin. Further, when the content of the crystalline resin is 10% by weight or less, the low-temperature fixing may be difficult due to an increase in the melting point of the toner. Furthermore, the document offset property of an image obtained using such toner may be deteriorated. Also, by controlling the melting characteristics of the crystalline resin contained in the toner by the resin acid value and the metal salt, it is hardly affected by the melting characteristics of the non-crystalline resin existing on the outermost surface under the thin film conditions. It is possible to control the melting characteristics of the toner.

(Crystalline resin)
The crystalline resin is not particularly limited as long as it is a crystalline resin, and specific examples include crystalline polyester resins and crystalline vinyl resins. From the viewpoint of adjusting the melting point within a preferable range, a crystalline polyester resin is preferable. An aliphatic crystalline polyester resin having an appropriate melting point is more preferable.

  Further, the “crystalline polyester resin” used in the toner according to the exemplary embodiment is obtained by polymerizing a component constituting polyester and other components in addition to a polymer having a 100% polyester structure as a constituent component. It also means a polymer (copolymer). However, in the latter case, the component other than the polyester constituting the polymer (copolymer) is 50% by weight or less.

  Examples of the crystalline vinyl resin include amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate. , Undecyl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, behenyl (meth) acrylate, etc. And vinyl resins using long-chain alkyl and alkenyl (meth) acrylic acid esters. In this specification, the description “(meth) acryl” means that both “acryl” and “methacryl” are included.

  The crystalline polyester resin and all other polyester resins used in the toner according to this embodiment are synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In addition, in this embodiment, a commercial item may be used as said polyester resin, and what was synthesize | combined suitably may be used.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids such as, and the like, and anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, when the particles are prepared by emulsifying or suspending the entire resin in water, if there are sulfonic acid groups, they can be emulsified or suspended without using a surfactant as described later.

  Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is contained in an amount of 1 to 15 mol%, preferably 2 to 10 mol%, based on all carboxylic acid components constituting the polyester. If the content is small, the stability of the emulsified particles over time may be deteriorated. On the other hand, if the content exceeds 15 mol%, not only the crystallinity of the polyester resin is lowered, but also the process of coalescence of particles after aggregation is adversely affected. In some cases, it may be difficult to adjust the toner diameter.

  Furthermore, it is more preferable to contain a dicarboxylic acid component having a double bond in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  As the polyhydric alcohol component, an aliphatic diol is preferable, and a linear aliphatic diol having 6 to 20 carbon atoms in the main chain portion is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. Further, when the number of carbon atoms is less than 6, when the polycondensation with an aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less. Further, in order to increase the crystallinity of the crystalline polyester resin used for the toner containing the crystalline resin, the total number of carbon atoms in the main chain portion of the dicarboxylic acid and the diol constituting the crystalline resin is 14 to 26. A range is preferable. To improve the reading accuracy of additional information by increasing the crystallinity of the crystalline polyester resin by setting the total number of carbons of the main chain portion of the dicarboxylic acid and diol constituting the crystalline resin to 17 to 19 Can do.

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester used in the toner according to the exemplary embodiment include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1, Examples thereof include, but are not limited to, 12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, considering availability, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyhydric alcohol components, the content of the aliphatic diol is preferably 80 mol% or more, and more preferably 90% or more. When the content of the aliphatic diol is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. .

  If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can be used for the purpose of adjusting the acid value and the hydroxyl value.

  Specific examples of the crystalline polyester resin include poly-1,2-cyclopropene dimethylene isophthalate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene oxide, polydecamethylene sebacate, polydecamethylene. Succinate, polyeicosamethylene malonate, polyethylene-p- (carbophenoxy) butyrate, polyethylene-p- (carbophenoxy) undecanoate, polyethylene-p-phenylene diacetate, polyethylene sebacate, polyethylene succinate, polyhexamethylene carbonate , Polyhexamethylene-p- (carbophenoxy) undecanoate, polyhexamethylene oxalate, polyhexamethylene sebacate, polyhexamethylene suberate, polyhexame Succinates, poly-4,4-isopropylidene diphenylene adipate, poly-4,4-isopropylidene diphenylene malonate, and the like.

  Further, trans-poly-4,4-isopropylidene diphenylene-1-methylcyclopropane dicarboxylate, polynonamethylene azelate, polynonamethylene terephthalate, polyoctamethylene dodecanediate, polypentamethylene terephthalate, trans-poly -M-phenylene cyclopropane dicarboxylate, cis-poly-m-phenylene cyclopropane dicarboxylate, polytetramethylene carbonate, polytetramethylene-p-phenylene diacetate, polytetramethylene sebacate, polytrimethylene dodecanedioate , Polytrimethylene octadecandioate, polytrimethylene oxalate, polytrimethylene undecandioate, poly-p-xylene adipate, poly-p-xylene azease Over DOO, poly -p- xylene sebacate, poly glycol terephthalate, cis - poly-1,4 (2-butene) sebacate, polycaprolactone and the like. In addition, a copolymer of a plurality of ester monomers used in these polymers, a copolymer of ester monomers, and other monomers copolymerizable therewith can be used.

  The melting point of the crystalline polyester resin is preferably in the range of 50 to 100 ° C, more preferably in the range of 55 to 95 ° C, and still more preferably in the range of 60 to 90 ° C. If the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. If the melting point is higher than 100 ° C., low-temperature fixing may be difficult.

Further, the crystalline polyester resin preferably has an ester concentration M represented by the following formula (1) of 0.05 or more and 0.11 or less.
M = K / A (1)
In the formula (1), M represents the ester concentration, K represents the number of ester groups (average number per molecule) contained in the crystalline polyester resin, and A represents the polymer chain of the crystalline polyester resin. The number of constituent atoms (average number per molecule) is represented. Here, the “ester concentration M” is an index indicating the content ratio of the ester group in the polymer of the crystalline polyester resin. The “number of ester groups contained in the crystalline polyester resin” represented by K in the formula (1) refers to the number of ester bonds contained in the entire crystalline polyester resin.

  The “number of atoms constituting the polymer chain contained in the crystalline polyester resin” represented by A in the formula (1) is the total number of atoms constituting the polymer chain of the crystalline polyester resin, and is an ester bond. It includes all the atoms involved in, but does not include the number of atoms in the branched portion in other constituent sites. That is, carbon atoms and oxygen atoms derived from carboxyl groups and alcohol groups involved in ester bonds (two oxygen atoms in one ester bond) and the six carbons constituting the polymer chain, for example, in the aromatic ring, Although included in the calculation of the number of atoms, for example, a hydrogen atom in an aromatic ring or an alkyl group, or an atom or atomic group of a substituent thereof constituting the polymer chain is not included in the calculation of the number of atoms.

  Explaining with a specific example, among the total of 10 atoms of 6 carbon atoms and 4 hydrogen atoms in the arylene group constituting the polymer chain, the above-mentioned “constituting the polymer chain contained in the crystalline polyester resin” The number of atoms to be included is only six of carbon atoms, and even if the hydrogen is replaced by any substituent, the atoms constituting the substituent are It is not included in the “number of atoms constituting the included polymer chain”.

The crystalline polyester resin has one repeating unit (for example, when the polymer is represented by H— [OCOR ₁ COOR ₂ O—] _n —H, the one repeating unit is represented in []). In the case of a single polymer consisting of only two ester bonds in one repeating unit (that is, the number of ester groups K ′ = 2 in the repeating unit), the ester concentration M is expressed by the following formula: (1-1).
M = 2 / A ′ (1-1)
In the above formula (1-1), M represents the ester concentration, and A ′ represents the number of atoms constituting the polymer chain in one repeating unit.

In the case where the crystalline polyester resin is a copolymer composed of a plurality of copolymer units, the number of ester groups K ^X and the number of atoms A ^X constituting the polymer chain are determined for each copolymer unit. It can be obtained by multiplying the polymerization ratios and summing them up and substituting them into the formula (1). For example, a compound [(Xa) _a (Xb) _b (Xc) having three copolymerized units of Xa, Xb and Xc and a copolymerization ratio of a: b: c (where a + b + c = 1) is used. _c ]] can be _calculated | required by following formula (1-2).
M = { ^KXa * a + ^KXb * b + ^KXc * c} / { ^AXa * a + ^AXb * b + ^AXc * c} (1-2)

In the above formula (1-2), M represents the ester concentration, K ^Xa represents the copolymer unit Xa, K ^Xb represents the copolymer unit Xb, and K ^Xc represents the number of ester groups in the copolymer unit Xc. ^Xa represents a copolymer unit Xa, A ^Xb represents a copolymer unit Xb, and A ^Xc represents the number of atoms constituting each polymer chain in the copolymer unit Xc.

  The ester concentration M of the crystalline polyester resin has a great influence on the chargeability of the toner produced using this. This is mainly due to the fact that the resin resistance varies depending on the ester concentration M. When the ester concentration M increases, the resin resistance decreases and the chargeability decreases. In the crystalline polyester resin used in the present embodiment, the ester concentration is preferably in the range of 0.05 to 0.11. In this case, sufficient chargeability and charge stability can be obtained, and a toner can be easily produced stably.

  When the ester concentration M is less than 0.05, the melting point of the crystalline polyester resin is increased, and the adhesion to the surface of the transfer medium such as paper is also lowered. Even if a sulfonic acid component is contained as a structural unit of the crystalline polyester resin, it may be difficult to stably produce a toner because of strong hydrophobicity and reduced solubility in a solvent. is there. Furthermore, since the monomer used for the synthesis of the crystalline polyester resin is also expensive, it may not be preferable in terms of cost. In addition, as a minimum of ester concentration, 0.055 is more preferable and 0.06 is still more preferable.

  On the other hand, if the ester concentration exceeds 0.11, the resin resistance may decrease and the chargeability of the toner may decrease. In addition, since the melting point becomes too low, the stability of the powder and the fixed image may be lowered. In addition, as an upper limit of ester concentration, 0.105 is more preferable and 0.102 is still more preferable.

  As described above, the binder resin used in the toner according to the exemplary embodiment is a crystalline polyester resin (hereinafter referred to as “polyester resin”) having an ester concentration M defined by the formula (1) in the range of 0.05 to 0.11. It is preferable to simply use “specific polyester resin” as the main component. Here, the “main component” refers to a main component among components constituting the crystalline resin and the amorphous resin used as the binder resin, and specifically, 50% by weight of the binder resin. The component which comprises the above is meant. However, in the present embodiment, among the binder resins, the specific polyester resin is more preferably 70% by weight or more, and further preferably 80% by weight or more.

  There is no restriction | limiting in particular as a manufacturing method of said crystalline polyester resin, It can manufacture with the general polyester polymerization method which makes an acid component and an alcohol component react, for example, direct polycondensation, transesterification method, etc. Depending on the type of monomer used as a synthetic raw material, it can be synthesized separately. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

  The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction is carried out while reducing the pressure in the reaction system as necessary to remove water and alcohol generated during condensation.

  When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. When a monomer having poor compatibility exists in the copolymerization reaction, the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound; phosphorous acid compound; phosphoric acid compound; and amine compound.

  Specifically, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxy , Titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetra Butoxide, Zirconium naphthenate, Zirconyl carbonate, Zirconyl acetate, Zirconyl stearate, Zirconyl octylate, Germanium oxide, Trif Alkenyl phosphite, tris (2,4-di -t- butyl-phenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  The acid value of the obtained crystalline polyester resin (mg number of KOH required to neutralize 1 g of resin) is easy to ensure the granulation property of the toner particles using the emulsion polymerization aggregation method described later. From the viewpoint of easily maintaining the chargeability and environmental stability (chargeability stability when the temperature and humidity are changed) of the obtained toner, it is preferably 5 to 30 mgKOH / g.

  The acid value of the crystalline polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio and reaction rate of the starting polyhydric carboxylic acid and polyhydric alcohol. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

[Amorphous resin]
Examples of the non-crystalline resin used in the toner according to the exemplary embodiment include conventionally known thermoplastic binder resins, and specific examples include styrenes such as styrene, parachlorostyrene, and α-methylstyrene. Homopolymer or copolymer (styrene-based resin); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, methacrylic acid Homopolymers or copolymers of vinyl groups such as ethyl, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc .; vinyl nitriles such as acrylonitrile and methacrylonitrile Homopolymer or copolymer (vinyl resin); vinyl methyl ether Homopolymers or copolymers of vinyl ethers such as vinyl isobutyl ether (vinyl resins); Homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl resins) ; Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, and isoprene (olefin-based resins); Non-vinyl condensation systems such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins And a graft polymer of these non-vinyl condensation resins and vinyl monomers. These resins may be used alone or in combination of two or more. Among these resins, vinyl resins and polyester resins are particularly preferable.

  In the case of a vinyl resin, it is advantageous in that a resin particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like. Examples of the vinyl monomers include vinyl polymer acids and vinyl polymer bases such as acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethyleneimine, vinylpyridine, and vinylamine. Examples include monomers as raw materials.

  In this embodiment, it is preferable that the resin particles contain the vinyl monomer as a monomer component. Among these vinyl monomers, vinyl polymer acids are more preferable from the viewpoint of ease of formation reaction of vinyl resins, and specifically, acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, etc. A dissociable vinyl monomer having a carboxyl group as a dissociating group is particularly preferred from the viewpoint of controlling the degree of polymerization and the glass transition point.

  The concentration of the dissociating group in the dissociable vinyl monomer is determined by dissolving particles such as toner particles from the surface, as described in, for example, polymer latex chemistry (Polymer Publications). Etc. can be determined. It should be noted that the molecular weight of the resin and the glass transition point from the surface of the particle to the inside can also be determined by the above method or the like.

  In the toner according to the exemplary embodiment, when a polyester resin is used as the non-crystalline resin, the resin particle dispersion can be easily prepared by emulsifying and dispersing the resin by adjusting the acid value of the resin or using an ionic surfactant. It is advantageous in that it can be prepared. The amorphous polyester resin used for emulsification dispersion is synthesized by dehydration condensation of a polyvalent carboxylic acid and a polyhydric alcohol.

  Examples of polycarboxylic acids include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, alkenyl Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination. Of these polyvalent carboxylic acids, it is preferable to use aromatic carboxylic acids, and in order to take a crosslinked structure or a branched structure in order to ensure good fixability, tricarboxylic or higher carboxylic acids (trimerits) It is preferable to use an acid or an acid anhydride thereof in combination.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, and other aliphatic diols, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct.

  One or more of these polyhydric alcohols can be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure good fixing properties, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  In addition, monocarboxylic acid and / or monoalcohol is further added to the polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol to esterify the hydroxyl group and / or carboxyl group at the polymerization terminal. The acid value of the polyester resin may be adjusted. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride and the like, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

  The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  Examples of the catalyst used for the synthesis of this polyester resin include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. The amount of such a catalyst added is preferably 0.01 to 1% by weight based on the total amount of raw materials. The catalyst used here becomes a factor in coloring the binder resin.

  The amorphous resin used in the toner according to the exemplary embodiment has a weight average molecular weight (Mw) of 5,000 to 1,000,000 as measured by a gel permeation chromatography (GPC) method of a soluble content of tetrahydrofuran (THF). More preferably, it is 7000-500000, the number average molecular weight (Mn) is preferably 2000-100000, the molecular weight distribution Mw / Mn is preferably 1.5-100, more preferably 2-2. 60.

  When the weight average molecular weight and the number average molecular weight are smaller than the above ranges, while effective for low-temperature fixability, not only the hot offset resistance is remarkably deteriorated, but also the glass transition point of the toner is lowered. The storage stability such as toner blocking is also adversely affected. On the other hand, if the molecular weight is larger than the above range, the hot offset resistance can be sufficiently provided, but the low-temperature fixability is deteriorated and the oozing of the crystalline polyester phase present in the toner is inhibited, so that the document storage stability is reduced. May be adversely affected. Therefore, it becomes easy to satisfy both the low-temperature fixability, the hot offset resistance, and the document storage stability by satisfying the above conditions.

  The molecular weight of the resin was measured with a THF solvent using a Toso GPC / HLC-8120, Tosoh column TSKgel SuperHM-M (15 cm), and a molecular weight calibration prepared with a monodisperse polystyrene standard sample. The molecular weight was calculated using a curve.

  The acid value of the polyester resin (the number of mg of KOH required to neutralize 1 g of the resin) makes it easy to obtain the molecular weight distribution as described above, and it is easy to ensure the granulation properties of the toner particles by the emulsion polymerization aggregation method. In addition, the environmental stability (stability of chargeability when the temperature and humidity change) of the obtained toner is easily maintained, so that it is preferably 1 to 30 mg KOH / g. The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio of the raw polyhydric carboxylic acid and polyhydric alcohol and the reaction rate. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

  The glass transition temperature of the amorphous resin used in the present embodiment is preferably in the range of 35 to 100 ° C., and in the range of 50 to 80 ° C. from the viewpoint of the balance between storage stability and toner fixability. More preferably. When the glass transition temperature is less than 35 ° C., the toner tends to easily block during storage or in the developing device (a phenomenon in which toner particles aggregate and become a lump). On the other hand, if the glass transition temperature exceeds 100 ° C., the fixing temperature of the toner becomes high, which is not preferable.

(Coloring agent)
The colorant used in the toner of the exemplary embodiment may be a dye or a pigment, but a pigment is preferable from the viewpoint of light resistance and water resistance.

  Preferred colorants include carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose bengal. Quinacridone, benzicine yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. A known pigment such as CI Pigment Blue 15: 3 can be used.

  Magnetic powder can also be used as a colorant. As the magnetic powder, known magnetic materials such as ferromagnetic metals such as cobalt, iron and nickel, alloys of metals such as cobalt, iron, nickel, aluminum, lead, magnesium, zinc and manganese, and oxides can be used.

  These can be used alone or in combination of two or more. The content of these colorants is preferably in the range of 0.1 to 40 parts by weight with respect to 100 parts by weight of the binder resin (that is, crystalline resin and non-crystalline resin) used for toner preparation. More preferably within the range of ˜30 parts by weight.

  The component constituting the toner in the exemplary embodiment is not particularly limited as long as it contains at least a binder resin and a colorant, but may contain other components such as a release agent as necessary. .

(Release agent)
The toner of the exemplary embodiment may contain a release agent, and the release agent is preferably contained in the core layer in the case of a core-shell structure. The toner contains a release agent, so that the releasability in the fixing process is improved, and in the contact heating type fixing method, the release oil applied to the fixing roll is reduced, or the release oil may not be used. That is, oilless fixing is possible. For this reason, it is possible to avoid a reduction in the life of the fixing roll due to the release oil and the occurrence of defects such as oil streaks, and also to reduce the cost of the fixing device.

  The release agent contained in the core layer is preferably not a single type but a combination of two types of release agents having different melting points (low melting point release agent / high melting point release agent). In particular, when the toner of the present embodiment has a shell layer mainly composed of an amorphous resin, essentially, the release agent component contained in the core layer tends to be suppressed from exuding to the fixed image surface layer. is there. For this reason, it may be difficult for a toner produced using only one type of release agent to ensure sufficient release properties in a wide temperature range. However, such a problem can be avoided by using a combination of two release agents having different melting points.

  As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide; carnauba Plant waxes such as wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; mineral and petroleum systems such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax And waxes; ester waxes such as fatty acid esters, montanic acid esters, carboxylic acid esters, pentaerythritol, higher alcohol esters; and the like. These waxes can be used in combination of two or more.

  Among these release agents, paraffin wax and pentaerythritol wax are particularly incompatible with crystalline resins as a low melting point release agent, so that the release agent is sufficiently leached onto the fixed image surface during fixing. In addition, the melting point is also preferable. As the high melting point release agent, paraffin wax and polyolefin wax are preferable for the same reason.

  Further, the melting point of the release agent is preferably in the range of 50 to 120 ° C., and more preferably not more than the melting point of the binder resin (crystalline resin and / or amorphous resin). When the melting point of the release agent is less than 50 ° C., the change temperature of the release agent is too low, the blocking resistance may be inferior, and the developability may deteriorate when the temperature in the copying machine increases. On the other hand, when the melting point exceeds 120 ° C., the change temperature of the release agent is too high, and the low-temperature fixability of the crystalline resin may be impaired. The melting point of the release agent can be measured by the same method as the melting point of the crystalline resin.

  The total content of the release agent is 4 to 22 parts by weight with respect to 100 parts by weight of the main components of the toner (that is, the total amount of the crystalline polyester resin, the amorphous resin, the release agent, and the colorant). The range is preferable, and the range of 6 to 16 parts by weight is more preferable. If the total content of the release agent is less than 4 parts by weight, there may be no effect of addition of the release agent. If it is 22 parts by weight or more, adverse effects on the chargeability tend to appear, and the toner is easily destroyed inside the developing device, so that the release agent or toner resin becomes spent on the carrier, and the charge tends to decrease. In addition to the effects such as, the granulation controllability is remarkably deteriorated, and it may be difficult to produce a toner having a desired particle size / distribution.

(Other additives)
In addition to the components described above, various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles may be added to the toner according to the exemplary embodiment as necessary. Can do.

  Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.

  Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, etc. Examples thereof include all inorganic fine particles used as an external additive on the toner surface.

  In addition, a filler such as silica or melamine can be added to the toner containing the crystalline resin in order to increase the crystallinity of the crystalline resin. The filler content is preferably in the range of 3 to 10% by weight based on the toner weight. By adding a filler to increase the crystallinity of the crystalline resin, the accuracy of reading additional information can be improved.

  Examples of inorganic particles externally added to the toner surface include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, and wollastonite. Diatomaceous earth, cerium chloride, bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. Among these, silica particles and titanium oxide particles are preferable, and hydrophobically treated particles are particularly preferable.

  Inorganic particles are generally used for the purpose of improving fluidity. The volume average particle diameter of the inorganic particles is preferably 1 to 200 nm, and the addition amount is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the toner.

  The organic particles externally added to the toner surface are generally used for the purpose of improving cleaning properties and transfer properties, and specific examples include polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and the like.

(Physical properties of toner for developing electrostatic image)
The volume average particle diameter D50v of the electrostatic image developing toner according to this embodiment is preferably in the range of 4 μm to 8 μm. If the volume average particle diameter D50v of the toner is smaller than 4 μm, the chargeability is insufficient and scattering to the surroundings occurs to cause image fogging, or the toner that could not be transferred could not be sufficiently cleaned, resulting in filming. It is not preferable because it causes it. On the other hand, when the volume average particle diameter D50v exceeds 8 μm, the resolution of the image is lowered and it tends to be difficult to achieve high image quality.

  The volume average particle size distribution index GSDv of the electrostatic image developing toner according to this embodiment is 1.27 or less, preferably 1.25 or less. When GSDv exceeds 1.27, the particle size distribution is not sharp, resolution is deteriorated, and image defects such as toner scattering and fogging are caused.

The volume average particle diameter D50v and the volume average particle size distribution index GSDv can be obtained by measuring with an aperture diameter of 100 μm using a Coulter Multisizer II type (manufactured by Beckman-Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more. Accumulate the volume and number from the smaller diameter side by drawing the cumulative distribution from the smaller particle size range (channel) divided based on the particle size distribution of the toner measured with Coulter Multisizer II (manufactured by Beckman-Coulter) The particle diameter that is 16% is defined as volume D16v and a number D16p, the particle diameter that is accumulated 50% is defined as volume D50v and a number D50p, and the particle diameter that is accumulated 84% is defined as volume D84v and number D84p. At this time, D50v represents the volume average particle diameter, and the volume average particle size distribution index (GSDv) is determined as (D84v / D16v) ^1/2 . In addition, (D84p / D16p) ^1/2 represents a number average particle size distribution index (GSDp).

In addition, the shape factor SF1 represented by the following formula of the toner for developing an electrostatic charge image according to this embodiment is preferably in the range of 110 to 140, more preferably in the range of 115 to 130.
SF1 = (ML ² / A) × (π / 4) × 100
[In the above formula, ML represents the maximum toner length (μm), and A represents the projected area (μm ² ) of the toner. ]
If the toner shape factor SF1 is less than 110 or exceeds 140, it may be impossible to obtain excellent chargeability, cleanability, and transferability over a long period of time.

  The shape factor SF1 is measured as follows using a Luzex image analyzer (FT manufactured by Nireco Corporation). First, an optical microscope image of the toner spread on the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projection area (A) of 50 toners are measured to obtain the shape factor SF1. .

<Method for producing toner for developing electrostatic image>
As a method for producing the toner for developing an electrostatic charge image according to the exemplary embodiment, a conventional kneading and pulverizing method, a colorant, a release agent, and the like are suspended together with a polymerizable monomer to polymerize the polymerizable monomer. Suspension polymerization method, resin, colorant, release agent and other toner constituent materials are dissolved in an organic solvent, dispersed in an aqueous solvent in a suspended state, and then the organic solvent is removed. There are wet manufacturing methods such as emulsion polymerization aggregation method, which are prepared by polymerization, heteroaggregated with a dispersion of colorant, release agent, etc., and then fused and coalesced. There is no particular limitation as long as the production method can be unevenly distributed. Among these, a wet production method such as a suspension polymerization method, a dissolution suspension method, and an emulsion polymerization agglomeration method is preferable, and it has toner particle size controllability, narrow particle size distribution, shape controllability, narrow shape distribution, and internal dispersion controllability. Therefore, the emulsion polymerization aggregation method is optimal.

  In general, the emulsion polymerization aggregation method is a step of emulsifying a binder resin or the like to form emulsified particles (droplets) and preparing a resin particle dispersion in which resin particles having a particle size of 1 μm or less are dispersed (hereinafter referred to as “emulsification”). Process particles), a resin particle dispersion, a colorant dispersion in which a colorant is dispersed, a release agent dispersion in which a release agent is dispersed, and the like are mixed to obtain resin particles, a colorant, and a release agent. A step of aggregating the agent into a toner particle size (hereinafter sometimes referred to as “aggregation step”), a step of heating the resin particles to a temperature equal to or higher than the glass transition point of the resin particles to fuse the aggregates to form toner particles (hereinafter “ Sometimes referred to as a “fusion process”).

[Emulsification process]
In the emulsification step, the emulsified particles (droplets) of the binder resin are formed by applying a shearing force to a solution obtained by mixing an aqueous solvent and a mixed liquid containing the binder resin.

  At that time, the viscosity of the mixed liquid can be lowered to form emulsified particles by heating or by dissolving the binder resin in an organic solvent. Moreover, a dispersing agent can also be used in order to stabilize emulsified particles and prevent thickening of the aqueous solvent. Such a dispersion of emulsified particles is referred to as a “resin particle dispersion”.

  Examples of the organic solvent include ethyl acetate, toluene, and the like, and can be appropriately selected and used according to the type and structure of the binder resin.

  As the usage-amount of the said organic solvent, it is preferable that it is the range of 50-5000 weight part with respect to 100 weight part of total amounts of resin, and it is more preferable that it is the range of 120-1000 weight part.

  Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and oleic acid. Anionic surfactants such as sodium, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, Such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, etc. Anion surfactants such as surfactants, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate.

  When an inorganic compound is used as the dispersant, a commercially available one may be used as it is, but a method of generating inorganic compound particles in the dispersant may be employed for the purpose of obtaining fine particles. As the usage-amount of the said dispersing agent, the range of 0.01-20 weight part is preferable with respect to 100 weight part of resin.

  Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. The size of the emulsified particles (droplets) of the resin is preferably in the range of 0.01 μm to 1 μm, more preferably in the range of 0.03 μm to 0.3 μm, in terms of the average particle size (volume average particle size). The range of 03 μm to 0.4 μm is more preferable.

  The colorant dispersion is produced by a method comprising a step of dispersing a colorant and a surfactant in an aqueous solvent to obtain a colorant dispersion.

  As a method for dispersing the colorant, an arbitrary method, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and the method is not limited at all.

  The addition amount of the colorant is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, and more preferably 2 to 10% by weight with respect to the total amount of the binder resin. More preferably, the range is 2 to 7% by weight.

  As the release agent, an aqueous dispersion of the release agent is prepared using a surfactant, or an organic solvent dispersion of the release agent is prepared using a dispersant. Such an aqueous dispersion or organic solvent dispersion of a release agent is referred to as a “release agent dispersion”. As the surfactant and dispersant used for dispersion, the same dispersants as used when dispersing the binder resin can be used.

[Aggregation process]
In the aggregation step, the obtained resin particle dispersion, colorant dispersion, and release agent dispersion are heated to a temperature near the melting point of the binder resin and below the melting point to form an aggregate. . The heating time may be performed so that the aggregation is sufficiently performed, and for example, it may be performed for about 0.5 hours to 10 hours.

  Formation of the aggregate of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. As the said pH, the range of 2-6 is preferable, The range of 2.5-5 is more preferable, The range of 2.5-4 is further more preferable. At this time, it is also effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Among these, an aluminum salt and a polymer thereof are particularly preferable. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more preferable.

  The solid content concentration of the reaction solution at the time of aggregation is usually in the range of 5% by weight to 20% by weight, preferably in the range of 10% by weight to 15% by weight. When the solid content concentration of the reaction solution is less than 5% by weight or exceeds 20% by weight, aggregation may not easily occur.

[Fusion process]
In the fusion step, under the same stirring as in the aggregation step, the aggregation suspension is stopped by setting the pH of the aggregate suspension to a range of 3 to 7, and heated at a temperature equal to or higher than the melting point of the crystalline polyester resin. To fuse the aggregates.

  There is no problem if the heating temperature is equal to or higher than the melting point of the binder resin.

  The heating time may be performed to such an extent that the fusion is sufficiently performed, for example, about 0.5 to 10 hours.

  In the fusion step, a crosslinking reaction may be performed when the binder resin is heated to the melting point or higher, or after the fusion is completed. Moreover, a crosslinking reaction can also be performed simultaneously with aggregation. When the crosslinking reaction is performed, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin is used, and a radical reaction is caused to the resin to introduce a crosslinked structure. . At this time, the following polymerization initiator can be used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycal) Nyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate Rate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

  These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the polymer and the type and amount of the coexisting colorant.

  The polymerization initiator may be mixed with the binder resin in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

(Shell layer forming process)
Next, a method for forming a shell layer as necessary will be described. In the toner according to the exemplary embodiment, a method for forming a shell layer includes an agglomeration step in which amorphous resin particles or the like are adhered to the aggregated particles (core particles) to form amorphous resin-adhered particles; And a melting step of forming the shell layer by heating the conductive resin adhering particles. About the formation method of the shell layer which has an amorphous resin particle as a main component, it is preferable to carry out in water from a viewpoint of productivity.

  The shell layer may be formed as the same process performed simultaneously by adding the amorphous particle dispersion during granulation by the emulsion polymerization aggregation method as described above, or as a separate process after the core particles are prepared. However, it is preferable to form the shell layer as a separate process in the aqueous medium after preparing the core particles.

  In the shell layer forming step, the solid content concentration during coating is preferably in the range of 10 to 50% by weight, more preferably in the range of 20 to 50% by weight, and in the range of 30 to 50% by weight. Is more preferable. If it is 10% by weight or less, not only the dispersion stability is low, but also the dispersion stability is lowered, and the adhesion of the amorphous resin particles to the core particle surface may be insufficient. On the other hand, when the solid content concentration is 50% by weight or more, an increase in slurry viscosity at the time of adhesion may cause an agitation failure, which may cause generation of coarse powder.

  In the formation of the shell layer, the slurry liquid may be heated for the purpose of obtaining a strong shell layer after adding the amorphous resin particle dispersion to the slurry liquid after granulation of the core particles. At this time, it is important to heat at or below the melting point or glass transition temperature of the binder resin of the core particles. When the heating temperature is too high, not only coarse powder is generated, but also the core component is eluted on the surface of the shell layer, which may deteriorate charging characteristics and heat storage properties.

  In the formation of the shell layer, a flocculant may be used for the purpose of promoting the coating of the amorphous resin particles. As the flocculant, the flocculant species described later is preferably used. Further, the timing of adding the flocculant may be before or after the addition of the amorphous resin particles.

  In the preparation of the toner shell layer of the present embodiment, as described above, the addition amount of the amorphous resin particles is preferably in the range of 5 to 25% by weight, and 7 to 20% by weight with respect to the weight of the core particles. Is more preferable, and it is further more preferable that it is the range of 7-16 weight%. When the addition amount is less than 5% by weight, the heat storage property becomes insufficient, and blocking is likely to occur in the actual machine. When the addition amount exceeds 25% by weight, there is no problem in thermal storage, but charging characteristics and low-temperature fixability may be hindered.

(Washing and drying process)
When toner particles are prepared using an emulsion polymerization aggregation method, etc., after removing the dispersant with an aqueous solution of strong acid such as hydrochloric acid, sulfuric acid, nitric acid, etc., rinse with ion exchange water etc. until the filtrate becomes neutral. A desired toner is obtained through a washing step, a solid-liquid separation step, and a drying step. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash with ion exchange water or the like in the washing step.

  In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. It is desirable that the toner particles have a moisture content after drying of 1.0% or less, preferably 0.5% or less.

<Electrostatic image developer>
In the exemplary embodiment, the electrostatic image developer is not particularly limited except that it contains the toner for developing an electrostatic image, and can have an appropriate component composition depending on the purpose. The electrostatic image developer may be used as a one-component electrostatic image developer by using an electrostatic image developing toner alone, or may be used in combination with a carrier as a two-component electrostatic image developer. Also good.

  For example, in the case of using a carrier, the carrier is not particularly limited, and examples thereof include known carriers. For example, resins described in JP-A Nos. 62-39879 and 56-11461 are disclosed. Known carriers such as a coated carrier can be used.

  Specific examples of the carrier include the following resin-coated carriers. Examples of the core particle of the carrier include normal iron powder, ferrite, magnetite molding, and the like, and the volume average particle size is in the range of about 30 to 200 μm.

  Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic acid 2 -Α-methylene fatty acid monocarboxylic acids such as ethylhexyl, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, etc. Vinyl nitriles; vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl Homopolymers such as vinyl ketones such as ketones; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers composed of two or more types of monomers Furthermore, silicone resins containing methyl silicone, methyl phenyl silicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by weight and more preferably in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the core particles.

  For manufacturing the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. .

  The mixing ratio of the electrostatic image developing toner and carrier in the electrostatic image developer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, toner: carrier = 1: 100 to 30: 100 The range of about 3: 100 to 20: 100 is more preferable.

<Image forming method>
The image forming method according to the present embodiment uses a latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier and a developer carried on the developer carrier, and is formed on the surface of the latent image carrier. A development process for developing the electrostatic latent image to form a toner image, a transfer process for transferring the toner image formed on the surface of the latent image holding body to the surface of the transfer target, and a toner transferred to the surface of the transfer target In the image forming method including the fixing step of fixing the image, the electrostatic image developer containing the electrostatic image developing toner of the present embodiment is used as the developer.

  The developer may be either a one-component system or a two-component system. As each of the above steps, a known step in the image forming method can be used. The image forming method according to the present embodiment may include steps other than the steps described above.

  As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used. In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are attached to the electrostatic latent image by contacting or approaching a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, the toner image transferred to the surface of the transfer target is heat-fixed by a fixing machine (fixing step) to form a final toner image.

  Examples of the transfer target (image output medium) to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.

  The developing device includes a developing device that holds toner that does not contain at least one crystalline resin, and a developing device that holds toner that contains at least one crystalline resin. As a combination of the developing devices, there are a developing device that holds toner containing no crystalline pigment and a crystalline resin, and four developing devices that use non-crystalline resin as a binder resin and have pigments of cyan, magenta, yellow, and black, respectively. A combination of the above or a crystalline resin as a binder resin, four developing units having cyan, magenta, yellow, and black as pigments, and an amorphous resin as a binder resin, and pigments as cyan, magenta, and yellow, respectively. A combination of four developing units with a total of eight developing units having black is preferable.

  In this embodiment, toner containing crystalline resin and toner not containing crystalline resin are fixed under the same fixing conditions, and X-ray diffraction intensity or glossiness is changed to give additional information to the image. can do. In order to add conventional information to an image with different glossiness using a conventional toner mainly composed of an amorphous resin, the fixing conditions are changed greatly (for example, about 130 ° C. for a normal image) The image to which additional information is applied needs to be fixed at a fixing temperature of about 200 ° C. Alternatively, it is necessary to provide a partial cooling device or the like. However, according to this method, additional information can be added to the image by fixing under the same fixing conditions and changing the glossiness.

(Invisible image and additional information)
In the image forming method according to the present embodiment, at least one image selected from the following (a), (b), and (c) is formed on the surface of the transfer object, and (a), (b), and (c) At least one of the invisible images is composed of a two-dimensional pattern. Here, additional information is given to the image by an invisible image.
(A) Only an invisible image is provided.
(B) An invisible image and a visible image are provided by being laminated.
(C) The invisible image and the visible image are separately provided in different regions on the surface of the transfer target.

  At this time, a visible image and an invisible image are formed on the surface of the transfer target (recording material) by the image forming apparatus. For example, the visible image is a portion developed with a developer containing a toner that does not contain a crystalline resin. A site developed with a developer containing toner containing a crystalline resin is used. The invisible image is a portion developed and laminated in one image with a developer containing a toner containing a crystalline resin and no colorant and a developer containing a toner containing no crystalline resin. The toner containing a crystalline resin and no colorant is preferably placed on the outermost surface of the image.

In the image forming method according to the present embodiment, when the difference in glossiness is used, at least one image selected from the following (a), (b), and (c) is formed on the surface of the transfer target, The invisible image of at least one of (a), (b), and (c) may be a two-dimensional pattern. Here, additional information is given to the image by visible images having different glossiness levels.
(A) Only a visible image including additional information is provided.
(B) A visible image including additional information and a normal visible image are stacked and provided.
(C) A visible image including additional information and a normal visible image are separately provided in different regions on the surface of the transfer target.

  At this time, a normal visible image and a visible image including additional information are formed on the surface of the transfer target (recording material) by the image forming apparatus. For example, the normal visible image is formed by a developer containing a toner not containing a crystalline resin. The visible part including the additional information is the part developed with the developer including the toner containing the crystalline resin. In addition, a visible image including additional information is laminated in one image by a developer including a toner containing a crystalline resin and not containing a colorant and a developer containing a toner not containing a crystalline resin. The toner may be a developed portion, and the toner containing a crystalline resin and not containing a colorant is preferably placed on the outermost surface of the image.

  An invisible image formed by the image forming method according to the present embodiment is formed by using a toner containing a crystalline resin, so that machine reading / decoding processing is stable over a long period of time by measuring X-ray diffraction intensity. This is possible, and information can be recorded with high density. Further, since the invisible image has no color developability in the visible light region and is invisible, any image on the image forming surface can be obtained regardless of whether or not the visible image is provided on the image forming surface of the transfer target. It can be formed in the region.

  Further, an invisible image formed by the image forming method according to the present embodiment is formed using toner containing a crystalline resin, so that machine reading / decoding processing is stable over a long period of time by measuring glossiness. This is possible, and information can be recorded with high density. Further, since the invisible image has no color developability in the visible light region and is invisible, any image on the image forming surface can be obtained regardless of whether or not the visible image is provided on the image forming surface of the transfer target. It can be formed in the region.

  Further, the visual recognition of the additional information due to the difference in glossiness is not limited only to obtain the genuine recognition / anti-counterfeit effect, and is formed at a specific position on the surface of the transfer object by, for example, a reader. When reading the additional information, it can be widely used for other purposes as a mark for recognizing the position where the additional information is recorded.

  Next, the image configuration of the invisible image formed by the image forming method in the present embodiment, the visual recognition of the invisible image, the machine reading of the invisible image, and the like will be specifically described.

  The invisible image is formed by using the electrostatic image developing toner, and is not particularly limited as long as it is machine-readable by X-ray diffraction intensity measurement or gloss measurement. Of course, it may be a two-dimensional pattern such as a known barcode called JAN, standard ITF, Code 128, Code 39, NW-7, or the like.

  When the invisible image is formed of a two-dimensional pattern such as a barcode, the serial number for specifying the image forming apparatus that has formed the image on the transfer target or the visible image formed on the transfer target surface together with the invisible image is displayed. It can be used as a copyright certification number for images. Moreover, when the visible image formed with an invisible image takes the form of a confidential document, securities, a license, a personal ID card, etc., it can also be used effectively to detect the identification of these counterfeits.

  In addition to the above barcode example, in the present embodiment, the two-dimensional pattern is not particularly limited as long as it is a known recording method that has been used as a visible and recognizable image. For example, as a method of forming a two-dimensional pattern in which minute area cells are geometrically arranged, a two-dimensional barcode called a QR code can be cited. In addition, as a method of forming a two-dimensional pattern in which minute line bitmaps are geometrically arranged, a code forming method using a plurality of patterns with different rotation angles, which is a technique described in Japanese Patent Laid-Open No. Hei 4-233683 Is mentioned.

  By forming such an invisible image consisting of a two-dimensional pattern on the surface of the transfer object, it is possible to embed large amounts of information, for example, music information, electronic files of text application software, etc. into the image in a format that cannot be visually understood. Therefore, it is possible to provide a technique for creating a more advanced confidential document or digital / analog information sharing document.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Synthesis of crystalline polyester resin particle dispersion (1)>
A 5 L flask was charged with 100 mol% of dimethyl sebacate, 100 mol% of hexanediol, and 0.2 parts by weight of dibutyltin oxide, and the atmosphere in the flask was changed to a nitrogen atmosphere, followed by reaction at 180 ° C. for 5 hours, followed by reduced pressure. The condensation reaction was carried out at 220 ° C. In the condensation reaction, the polymer produced in the middle is sampled, and the molecular weight is measured by gel permeation chromatography (GPC), whereby Mw (weight average molecular weight) = 18000 and Mn (number average molecular weight) = 8000. The reaction was stopped and a crystalline polyester resin (1) was obtained. The melting point (temperature at the maximum peak measured by DSC) of the obtained crystalline polyester resin (1) was 71.5 ° C.

Next, a crystalline resin particle dispersion was prepared.
Crystalline polyester resin (1) 90 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 3 parts by weight Ion-exchanged water 200 parts by weight After dispersion at T50, dispersion treatment is performed with a gorin homogenizer for 1 hour, and then ion-exchanged water is added so that the solid content concentration of the dispersion becomes 20%, and a crystalline polyester resin particle dispersion having a volume average particle size of 150 nm (Crystalline resin latex) (1) was obtained. The volume average particle diameter of the dispersed resin particles was measured with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.). The glass transition point was measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50). In addition, the weight average molecular weight (Mw, in terms of polystyrene) was measured using a gel permeation chromatography molecular weight measuring device (manufactured by Tosoh Corporation, HLC-8020), a column manufactured by Tosoh Corporation, TSKgel SuperHM-M (15 cm), Measurements were made using a molecular weight calibration curve created with a monodisperse polystyrene standard sample.

<Preparation of Sian pigment dispersion B-1>
Cyan pigment C.I. I. Pigment Blue 15: 3 (copper phthalocyanine, manufactured by Dainippon Ink & Chemicals) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 5 parts by weight Ion-exchanged water 200 parts by weight The above composition is mixed and dissolved. Dispersion was performed by homogenizer (IKA Ultra Tarrax) and ultrasonic irradiation to obtain a cyan pigment dispersion B-1 having a volume average particle size of 150 nm. Ion exchange water was added to adjust the solid content concentration to 20%.

<Preparation of yellow pigment dispersion Y-1>
A pigment dispersion Y-1 was obtained through the same process except that the pigment and surfactant in the cyan pigment dispersion were changed to the following. Ion exchange water was added to adjust the solid content concentration to 20%.
Yellow pigment C.I. I. Pigment Yellow 74 (manufactured by Clariant)
60 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 7 parts by weight

<Preparation of magenta pigment dispersion M-1>
A pigment dispersion M-1 was obtained through the same process except that the pigment and surfactant in the cyan pigment dispersion were changed to the following. Ion exchange water was added to adjust the solid content concentration to 20%.
Magenta pigment C.I. I. Pigment Red122 (manufactured by Clariant) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 6 parts by weight

<Preparation of black pigment dispersion K-1>
A pigment dispersion K-1 was obtained through the same process except that the pigment and surfactant in the cyan pigment dispersion were changed to the following. Ion exchange water was added to adjust the solid content concentration to 20%.
Carbon black (Cabot, Regal 330) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 6 parts by weight

<Preparation of release agent dispersion (1)>
Paraffin wax (Nippon Seiwa Co., Ltd., HNP-9, melting point 75 ° C.) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 0.5 parts by weight Ion-exchanged water 200 parts by weight The above components were heated to 95 ° C. and dispersed using a homogenizer (manufactured by IKA, Ultra Turrax T50), then dispersed with a Manton Gorin high-pressure homogenizer (Gorin), and the average particle size was 200 nm. A release agent dispersion (1) (release agent concentration, 20% by weight) obtained by dispersing the mold was prepared.

<Synthesis of Amorphous Polyester Resin Particle Dispersion (1)>
85 mol% terephthalic acid, 15 mol% dodecenyl succinic acid, 95 mol% bisphenol A propylene oxide 2 mol adduct, 5 mol% cyclohexanedimethanol were charged into a 5 L flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, rectifying column, The temperature was raised to 200 ° C. over 2 hours, and 1.3 parts by weight of titanium tetrabutoxide was added. Further, the temperature was raised to 240 ° C. while distilling off water, the condensation was advanced, the polymer produced during the sampling was sampled, and the molecular weight was measured by gel permeation chromatography (GPC) to obtain Mw (weight average molecular weight). ) = 10000, the reaction was stopped to obtain an amorphous polyester resin (1).

  Subsequently, 100 parts by weight of this resin was dissolved in 50 parts by weight of ethyl acetate and 10 parts by weight of isopropanol. After stirring, 380 parts by weight of water was added dropwise with stirring, the solvent was distilled off with an evaporator, and the solid content concentration of the dispersion liquid Was added ion-exchanged water so as to be 35%. The resulting amorphous resin latex had a weight average molecular weight Mw of 10,000, a number average molecular weight Mn of 5500, a glass transition temperature Tg of 57 ° C., and a volume average particle size of 120 nm.

<Synthesis of Amorphous Polyester Resin Particle Dispersion (2)>
Among the conditions of the amorphous polyester resin particle dispersion (1), an amorphous polyester resin particle dispersion (2) was prepared under the same conditions except that terephthalic acid was changed to 95 mol% and dodecenyl succinic acid was changed to 5 mol%. The resulting amorphous resin latex had a weight average molecular weight Mw of 12000, a number average molecular weight Mn of 6000, a glass transition temperature Tg of 67 ° C., and a volume average particle size of 130 nm.

<Preparation of crystalline resin toner (1) and developer>
A mixture of the following composition was put into a round stainless steel flask, adjusted to pH 3 with nitric acid, mixed and dispersed with Ultra Turrax T50, and the contents in the flask were stirred with an oil bath for heating. Heat to 48 ° C. and hold at 48 ° C. for 1 hour.
Crystalline polyester resin particle dispersion (1) 110 parts by weight Amorphous polyester resin particle dispersion (1) 150 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 8 parts by weight Pigment dispersion B-1 30 parts by weight Release agent dispersion (1) 60 parts by weight Polyaluminum chloride 0.16 parts by weight Deionized water 400 parts by weight

  Thereafter, 100 parts by weight of the amorphous polyester resin particle dispersion (1) and 4 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) were added to the mixture. After maintaining the temperature at 48 ° C. for 1 hour, sodium hydroxide was added to adjust the pH to 9. Thereafter, the temperature of the heating oil bath was raised to 90 ° C., and the core aggregates were fused and united. Immediately after the stirring was stopped, the solution in the flask was rapidly cooled using a heat exchanger. The temperature lowering rate at this time was 15 ° C./min.

  Subsequently, the cooled solution in the flask was filtered, sufficiently washed with ion exchange water, and dried to obtain a toner. When the particle size of the amorphous core fusion (1) was measured with a Coulter counter (TA2 type, manufactured by Coulter, Inc.), the volume average particle size D50v was 6.5 μm. Next, 100 parts by weight of the toner (1A) after the drying treatment, 1 part by weight of metatitanic acid (average particle size 40 nm, i-butyltrimethoxysilane treated product), silica (volume average particle size 140 nm, sol-gel method) were used. HMDS (hexamethyldisilazane) treated product) 2 parts by weight and 1 part by weight of non-colored composite particles C were added and blended with a Henschel mixer at a peripheral speed of 30 m / s × 15 minutes, and then a sieve having an opening of 45 μm was added. Thus, coarse particles were removed, and a toner added with an external additive was obtained.

  Subsequently, 100 parts by weight of a carrier for DCC500 (Docucenter Color 500) manufactured by Fuji Xerox Co., Ltd. and 10 parts by weight of toner added with an external additive were stirred in a V-blender at 40 rpm × 20 minutes, and sieved with a sieve having an opening of 212 μm. The developer (HC-1) was obtained by dividing.

  In addition, the developer HY-1, HM-1, HK-1, and HT are changed by changing the pigment dispersion to Y-1, M-1, and K-1, respectively, or by changing the condition that the pigment dispersion is not used. -1 was obtained respectively.

<Preparation of crystalline resin toner (2) and developer>
A developer HC-2 was obtained in the same manner as in the crystalline resin toner (1) except that 2 parts by weight of AEROSIL130 (silica particles manufactured by Nippon Aerosil Co., Ltd.) was added as a filler. Further, the developer dispersions YY-2, HM-2, HK-2, and HT-2 are changed by changing the pigment dispersion to Y-1, M-1, and K-1, respectively. Obtained.

<Preparation of Amorphous Resin Toner (1) and Developer>
A crystalline polyester resin particle dispersion (1) was entirely replaced with the amorphous polyester resin particle dispersion (1) (215 parts by weight of core latex) to obtain developer AC-1. Also, the developer AY-1, AM-1, AK-1, and AT-1 are changed by changing the pigment dispersion to Y-1, M-1, and K-1, respectively, or not using the pigment dispersion. Obtained.

<Preparation of Amorphous Resin Toner (2) and Developer>
A crystalline polyester resin particle dispersion (1) was entirely replaced with an amorphous polyester resin particle dispersion (2) (215 parts by weight of core latex) to obtain developer AC-2. In addition, the developer AY-2, AM-2, AK-2, and AT-2 are changed by changing the pigment dispersion to Y-1, M-1, and K-1, respectively, or not using them. Obtained.

<Preparation of Amorphous Resin Toner (3) and Developer>
The crystalline polyester resin particle dispersion (1) is entirely replaced with the amorphous polyester resin particle dispersion (1) (215 parts by weight of the core latex), and further, a copper phosphorylated crystal glass dye (CuO) as a near infrared light absorbing material. Is 40% by mass, Al ₂ O ₃ is 5% by mass, P ₂ O ₅ is 50% by mass, and K ₂ O is 5% by mass. And then pulverized until the average particle size becomes 1 μm.) To obtain a developer AC-3. Also, the developer AY-3, AM-3, AK-3, and AT-3 were changed by changing the pigment dispersion to Y-1, M-1, and K-1, respectively, or not using them. Obtained.

<Development evaluation>
The development unit of DCC500 (Docucenter Color 500) manufactured by Fuji Xerox Co., Ltd. was remodeled so that it could be developed with a total of eight developers, and each of the four developer A and four developer B colors was developed. The image was formed under the same conditions as the DCC500 product, such as the fixing temperature, paper feed speed, and development potential. Alternatively, when developer A did not contain a pigment, it was stored in five developing devices of four colors, developer A and developer B, and an image was formed in the same manner.

  A4 size white paper (Fuji Xerox, P-A4 paper, width: 210 mm, length: 297 mm) was used as the transfer material used in the image formation test. In the image forming test in each example and comparative example, the developer prepared in each example and comparative example was supplied to the developing device.

(Example 1)
Toner containing a crystalline resin (Developer A: HC-1, HY-1, HM-1, HK-1) and a toner containing no crystalline resin and not containing a crystalline resin (Developer B: AC -1, AY-1, AM-1, and AK-1) were used in combination (including pigments) to form an image. With the image forming apparatus, a visible image and an invisible image were formed in different areas on the surface of the transfer target 14 as shown in FIG. A visible image was developed with developer B in the second image area 12, and an invisible image was developed with developer A as additional information in the first image area 10. That is, in FIG. 1, a portion (first image region 10) that appears as X in the solid image of the patch was developed with developer A, and the remaining portion (second image region 12) was developed with developer B. Evaluation was performed by the following method. Difference in image glossiness ◎, difference ○ due to X-ray diffraction intensity, and change in color tone ◯. The results are shown in Table 1.

[X-ray diffraction intensity evaluation]
With an XRD apparatus (RAD-II C-type X-ray diffraction intensity measuring apparatus manufactured by Rigaku Corporation), an X-ray diffraction intensity of 2θ = 17 ° is set to X6 for X-ray diffraction of a part with an invisible image formed with developer A. When the X-ray diffraction intensity at 2θ = 21.5 ° is X5, it is determined that the X-ray diffraction intensity is obtained if (X5−X6) / X6 is 0.1 or more. The X-ray diffraction intensity was mapped for each part of the image and evaluated according to the following criteria.
○: The position where the invisible image is formed can be mapped by the X-ray diffraction intensity. X: The position where the invisible image is formed cannot be mapped by the X-ray diffraction intensity.

[Glossiness evaluation]
Fixing is performed with the fixing roller temperature set at 160 ° C., and the gloss is measured with a gloss meter (manufactured by BYK-Gardner, set at a single angle of incidence / reflection of 60 °). The difference due to the 60 ° gloss of the image portion was evaluated according to the following criteria.
A: 20 or more (distinguishable visually and mechanically, that is, a visible image provided with additional information)
○: 10 or less (not visually discernable, but mechanically distinguishable, that is, invisible image)
(Triangle | delta): 10-20 (it can distinguish somehow visually, but there is much noise and it can distinguish mechanically.)

[Color change]
○: No visual color change ×: Visual color change

[Reading accuracy]
In this evaluation, the information restoration rate (%) was defined as the number of times that the information by the invisible image could be accurately restored when the image reading apparatus performed reading 500 times. If the invisible information restoration rate (%) is 90% or more, the level is practically acceptable.
◎: Information restoration rate is 95% or more ○: Information restoration rate is 90% or more and less than 95% △: Information restoration rate is 75% or more and less than 90% ×: Information restoration rate is less than 75%

(Example 2)
Toner containing crystalline resin and no pigment (Developer A: HT-1) and toner using non-crystalline resin (Developer B: AC-1, AY-1, AM-1, AK-1) ) Were used in combination to form an image, and the following evaluation was performed. An invisible image developed with developer A was formed on the visible image developed with developer B on the surface of the transfer medium by an image forming apparatus. Difference in image glossiness ◎, difference ○ due to X-ray diffraction intensity, and change in color tone ◯. The results are shown in Table 1.

(Example 3)
Toner containing crystalline resin and filler (Developer A: HC-2, HY-2, HM-2, HK-2) and toner using non-crystalline resin (Developer B: AC-1, AY- 1, AM-1, and AK-1) were used in combination (each including a pigment) to form an image and evaluated. Difference in image glossiness ◎, difference ○ due to X-ray diffraction intensity, and change in color tone ◯. The results are shown in Table 1.

(Comparative Example 1)
Toners using non-crystalline resins having different glass transition points (Tg) (Developer A: AC-1, AY-1, AM-1, AK-1, Developer B: AC-2, AY-2, AM -2, AK-2) An image was formed and evaluated in the same manner as in Example 1 except that two types were used in combination (both pigments were included). Difference in image gloss, difference due to X-ray diffraction intensity, and change in color tone. The results are shown in Table 1.

(Comparative Example 2)
Two toners (developer A: AT-1, developer B: AC-2, AY-2, AM-2, AK-2) using non-crystalline resins having different glass transition points (Tg) are used in combination ( An image was formed and evaluated in the same manner as in Example 1 except that the lower Tg contained no pigment). Difference in image gloss, difference due to X-ray diffraction intensity, and change in color tone. The results are shown in Table 1.

(Comparative Example 3)
Non-crystalline resin toner (Developer A: AC-3, AY-3, AM-3, AK-3) containing near infrared light absorbing material and non-crystalline resin toner containing no near infrared light absorbing material Images were formed and evaluated in the same manner as in Example 1 except that (Developer B: AC-2, AY-2, AM-2, AK-2) were used in combination. The difference in image gloss was Δ, the difference due to X-ray diffraction intensity was x, and the change in color tone was x.

  In this way, a specific X-ray diffraction attributed to the crystalline resin is formed by using the toner containing the crystalline resin and the toner containing no crystalline resin and containing the amorphous resin in combination. By varying the X-ray diffraction intensity at the peak diffraction angle, it was possible to form an invisible image with additional information added to the image without inhibiting the color tone of the image. Moreover, the reading accuracy was improved by including a filler as in Example 3.

  In addition, by combining two types of toner containing a crystalline resin and a toner containing a non-crystalline resin and containing a non-crystalline resin to form an image, the glossiness resulting from the crystalline resin is made different. It was possible to form a visible image with additional information added to the image without inhibiting the color tone of the image.

It is the schematic which shows an example of the image formation which provided the additional information in the Example of this invention.

Explanation of symbols

10 First image region (additional information), 12 Second image region, 14 Transfer object.

Claims (4)

An image forming method for adding additional information to an image,
Forming a first image area using a toner containing a crystalline resin and a second image area using a toner not containing a crystalline resin;
The additional information is given by making the first image region and the second image region have different X-ray diffraction intensity or glossiness at a diffraction angle of a specific X-ray diffraction peak caused by the crystalline resin. An image forming method. The image forming method according to claim 1,
When the X-ray diffraction intensity of a specific X-ray diffraction peak due to the crystalline resin in the first image region is X1, and the reference intensity at a predetermined diffraction angle is X2, (X1-X2) / X2 ≧ 0.1,
When the X-ray diffraction intensity at the diffraction angle of the specific X-ray diffraction peak in the second image region is X3 and the reference intensity at the predetermined diffraction angle is X4, (X3-X4) / X4 <0. 1. An image forming method, wherein The image forming method according to claim 1,
An image forming method, wherein G1-G2> 5, where G1 is G1 in the first image area and G2 is G2 in the second image area. The image forming method according to any one of claims 1 to 3,
The image forming method, wherein the toner containing no crystalline resin contains an amorphous resin.

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