JP2006215537A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a full-color image forming method which ensures a short rising time, enables fixing of a small-particle-diameter toner at low temperature, and is free of a glossy abnormal image, and to provide a fixing device which ensures a short rising time and enables fixing at low temperature, and a full-color image forming apparatus using the fixing device and free of an abnormal image. <P>SOLUTION: In the image forming method, a belt fixing system is adopted by which a multicolor image is formed by overlapping toner images of different colors, fixing nip time is 30-100 ms, fixing pressure is 0.5-3 kgf/cm<SP>2</SP>, and the toner contains at least a crystalline polyester A and an amorphous resin B. The image forming apparatus is for implementing the method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method and an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic process.

Conventionally, as a fixing method used in the dry development method, a heating heat roller method is widely used because of its energy efficiency. In recent years, in order to save energy by fixing the toner at a low temperature, the thermal energy given to the toner during fixing tends to be small. The 1999 International Energy Agency (IEA) Demand-Side Management (DSM) program has a technology procurement project for next-generation copiers, and the required specifications are made public. Achieving dramatic energy savings compared to conventional copiers is required so that the time is within 10 seconds and the standby power consumption is 10-30 watts or less (differs depending on the copying speed). As a way to achieve this requirement,
(1) Reducing the heat capacity of the fixing member (2) Reducing the toner at a low temperature is considered to be an essential technical achievement.

  Methods for heat-fixing a toner image on a transfer paper are roughly classified into a contact fixing method and a non-contact fixing method. The former includes heating roller fixing, belt fixing, the latter includes flash fixing, and oven (atmosphere) fixing. The belt fixing method is an extremely heat efficient fixing method because the toner image and the heating roller are in direct contact. In the belt fixing system disclosed in Patent Document 1, as shown in FIG. 1, a fixing roller 100, a heating roller 110, an endless fixing belt 120 stretched between both rollers, and the fixing belt 120 are provided. And a pressure roller 130 provided to face the fixing roller 100. Here, the fixing belt 120 is wound around the pressure roller 130 to form a nip N between the fixing belt 120 and the pressure roller 130, and the heating roller 110 is disposed in front of the entrance g of the nip N. . In this case, the fixing belt 120 having a small heat capacity is heated in advance and then the toner is fixed to the recording material 140 passing through the nip N. The rise time is relatively short, and the wide nip width L is used, so that There is a feature that it can be fixed.

In terms of the low-temperature fixing of toner, an attempt has been made to use a polyester resin having excellent low-temperature fixability and relatively good heat-resistant storage, in place of styrene-acrylic resins that have been frequently used. However, for further low-temperature fixing, it is necessary to control the thermal characteristics of the resin itself. However, if the glass transition temperature (Tg) is lowered too much, the heat-resistant storage stability is deteriorated or the molecular weight is decreased. If the softening temperature [T (F1 / 2)] of the resin is lowered too much, there are problems such as lowering the hot offset occurrence temperature. For this reason, even a polyester resin excellent in low-temperature fixability has not yet obtained a toner having excellent low-temperature fixability and high hot offset occurrence temperature by controlling the thermal characteristics of the resin itself.
In order to solve this problem, an attempt to add a specific non-olefinic crystalline polymer having sharp melt properties at the glass transition temperature in the binder resin (Patent Document 2) or an attempt to use a crystalline polyester (patent) Document 3, Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7).

  In recent years, with the development of digital copying machines, laser printers, etc., there is a high demand for higher image quality. In particular, for printers, at present, a high image quality of 300 dpi is the mainstream, but in the future, it is expected that the image quality will be further advanced to 480 dpi and 600 dpi. Under such circumstances, it is inevitable that the use of a toner having a smaller particle size is required more severely. It is known that when the toner particle size is small, it is difficult to apply pressure to the toner particles even if the pressure is applied between the fixing members, so that the fixability is deteriorated. In particular, in the case of a fixing device having a low surface pressure such as belt fixing, this tendency becomes remarkable. In order to achieve low temperature fixing using the heating belt fixing method, it is necessary to optimize the toner prescription design in consideration of fixing conditions, toner particle size, and melting characteristics in accordance with the characteristics of the fixing method.

JP-A-10-30796 JP 62-63940 A JP 2003-167384 A Japanese Patent No. 2931899 JP 2001-222138 A JP 2004-221740 A JP 2004-279476 A

In view of the above problems, an object of the present invention is to provide a full-color image forming method in which a rise time is short, a small particle size toner can be fixed at a low temperature, and there is no glossy abnormal image.
Another object of the present invention is to provide a fixing device capable of fixing at a low temperature with a short rise time, and to provide a full-color image forming apparatus using the fixing device without an abnormal image.

A first aspect of the present invention is a belt fixing type image forming method in which toner images of different colors are superimposed to form a multicolor image, and the fixing nip time is 30 to 100 msec and the fixing pressure is 0.5 to 3 kgf / cm ^2, and and the toner is an image forming method which is a toner containing at least a crystalline polyester a and the amorphous resin B as the binder resin.
According to a second aspect of the present invention, the fixing device includes an endless fixing belt stretched between the fixing roller and the heating roller, and a pressure roller provided to face the fixing roller via the fixing belt, Heating and pressurizing an unfixed toner image carried on a recording material by a nip including a portion where the fixing belt is wound around the pressure roller and a portion where the fixing roller and the pressure roller are in contact with each other with the fixing belt interposed therebetween. The image forming method according to claim 1.
According to a third aspect of the present invention, the fixing device is provided inside the fixing belt conveyance path so as to bend the conveyance path, and has a guide member for increasing the tension of the fixing belt at the nip entrance, and the guide member is pressurized. The image forming method according to claim 1, wherein the fixing belt reaching between the rollers is stretched away from the pressure roller.
According to a fourth aspect of the present invention, the belt heating means has a configuration in which a radiant heating source or an induction heating heat source is provided as a heat source in either or both of the inside and outside of the heating belt. The present invention relates to the image forming method according to any one of.
5th of this invention is a structure in which the belt heating means provided the radiant heat source at least in this conveyance roller among a pressurization roller and a conveyance roller, In any one of Claims 1-4 characterized by the above-mentioned. The present invention relates to an image forming method.
A sixth aspect of the present invention relates to the image forming method according to any one of claims 1 to 5, wherein the glass transition point of the polyester resin A is in the range of 80 to 130 ° C.
A seventh aspect of the present invention relates to the image forming method according to any one of claims 1 to 6, wherein the content of the polyester resin A in the binder resin is 1 to 50% by weight.
In an eighth aspect of the present invention, the alcohol component constituting the polyester resin A comprises at least one selected from 1,4-butanediol and 1,6-hexanediol, while the acid constituting the polyester resin A 8. The image forming method according to claim 1, wherein the component comprises at least one selected from maleic acid and fumaric acid.
9th of this invention consists of at least 1 chosen from maleic acid and fumaric acid as the acid component which comprises the amorphous polyester B, It is described in any one of Claims 1-8 characterized by the above-mentioned. The present invention relates to an image forming method.
According to a tenth aspect of the present invention, the toner is an electrostatic charge developing toner containing a releasing agent, and the releasing agent has a glass transition point of 70 to 90 ° C. The image forming method according to any one of?
According to an eleventh aspect of the present invention, the release agent is one or more selected from a liberated fatty acid type carnauba wax, a polyethylene wax, a montan wax, and an oxidized rice wax. The image forming method according to any one of the above.
In the twelfth aspect of the present invention, the toner used has a weight average particle diameter of 3 to 8 μm, and the ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) is 1.00. The image forming method according to claim 1, wherein the image forming method is in a range of 1.40.
A thirteenth aspect of the present invention relates to an image forming apparatus used in the image forming method according to any one of the first to twelfth aspects.

As a result of studying a fixing method at a low temperature and having a short rise time, the inventors have determined that the fixing pressure of the fixing device, the fixing nip in a combination of a toner formulated with a crystalline polyester resin excellent in low temperature fixing property and a belt fixing device. We have found that there is an optimal numerical range for time.
(1) Toner prescription:
The polyester resin A having crystallinity undergoes a crystal transition at the glass transition temperature (Tg), and at the same time, the melt viscosity suddenly decreases from the solid state and exhibits a fixing function to a recording medium such as paper. On the other hand, an amorphous resin usually used as a toner resin has a temperature at which the melt viscosity gradually decreases from Tg, and the melt viscosity decreases as Tg and a fixing function are expressed [for example, softening temperature T (F1 / 2)]. There is a difference of several tens of degrees Celsius. Accordingly, in order to fix a toner using only an amorphous resin at a low temperature, it is necessary to lower T (F1 / 2) by lowering the resin Tg or lowering the molecular weight. Heat resistant storage stability and hot offset resistance tend to be insufficient.
Therefore, by combining a crystalline polyester resin and an amorphous resin, low temperature fixing due to a decrease in melt viscosity without deteriorating heat-resistant storage stability and hot offset resistance, which was not possible with an amorphous resin alone. Can be achieved.

(2) Fixing pressure:
The fixing pressure is preferably 0.5 to ³ kgf / cm ² . In order to shorten the rise time, it is essential to reduce the thickness of the fixing member. To achieve the reduction in thickness, the fixing pressure is preferably low, and is preferably 3 kgf / cm ² or less. On the other hand, in full color image formation in which multicolor images are formed by superimposing different color toner images, multiple overlapping toner layers of different colors are uniformly melted and integrated to form a smooth toner layer. When the fixing pressure is lower than 0.5 kgf / cm ² , the overlapping toner layers of different colors do not melt uniformly and do not form a smooth toner layer, resulting in low image gloss and transparency. Bad image. Further, there are problems such as poor toner fixability due to a small amount of toner deformation during fixing and low image density due to a small toner spread.

(3) Fixing nip time:
The fixing nip time is preferably 30 to 100 msec. In order to increase the printing speed and reduce the size of the apparatus, it is essential to shorten the fixing nip time, and it is preferably 100 msec or less. When the fixing nip time is shorter than 30 msec, the toner heating time is insufficient, so that the same problem as when the fixing pressure is lower than 0.5 kgf / cm ² occurs.

(Toner structure)
(2) At the same time as the fixing conditions of (3), ie, low fixing pressure and long fixing nip time, it penetrates into the paper fiber as the recording medium and the toner melts and spreads sufficiently on the paper to obtain a high image density. The content of the crystalline polyester resin for making the toner excellent in heat-resistant storage stability needs to be 5% by weight or more based on the total amount of the binder resin in order to exhibit the effect on the low-temperature fixability. If this amount is large, the effect on fixing at low temperature is great, but if it is too large, the resin having crystallinity deteriorates the hot offset resistance. Accordingly, it is preferably at most 50% by weight. More preferably, it is 40% by weight or less.
Since the resin having crystallinity rapidly decreases in melt viscosity at the glass transition temperature (Tg), it is possible to control the minimum fixing temperature not only by its content but also by Tg and T (F1 / 2). is there. In this invention, it is preferable that it is low in the range which does not deteriorate heat-resistant storage stability, Tg of the polyester resin which has crystallinity is in the range of 80-130 degreeC, and T (F1 / 2) is in the range of 80-130 degreeC. Is preferred. When Tg and T (F1 / 2) are lower than the above ranges, it is difficult to synthesize a crystalline polyester that has sharp melt properties and easily exhibits an effect on low-temperature fixability. Since the lower limit temperature becomes high, low temperature fixability cannot be obtained.

The toner of the present invention contains a crystalline polyester resin A and an amorphous resin B which are substantially incompatible with each other in the toner, and both are present in an incompatible phase-separated state in the toner. Therefore, it has excellent hot offset resistance and low-temperature fixability. That is, in the toner of the present invention, the crystalline polyester resin A and the non-crystalline resin B exist in a phase-separated state, so that the crystalline polyester resin A and the non-crystalline resin B have their respective characteristics. To express. That is, the amorphous resin B having a high T (F1 / 2) increases the elasticity of the toner and improves the hot offset resistance, while the crystalline polyester A having a low T (F1 / 2) has a low temperature fixability. To improve.
In the toner, whether or not the polyester resin A and the resin B exist in a phase-separated state can be confirmed by any of the following methods.

(1) DSC (differential thermal analysis) of toner The presence or absence of the formation of a phase separation structure can be confirmed by measuring an endothermic peak due to the first temperature increase. In the DSC endothermic peak measurement, there are at least three endothermic peaks (A), (B), and (C) attributed to the amorphous resin B, the release agent, and the crystalline polyester resin A, respectively. Endothermic peak (A) having a peak top in the range of 40 to 70 ° C. and endothermic peak (B) attributed to the release agent having a peak top in the range of 70 to 90 ° C. The endothermic peak (C) attributed to the polyester resin A has a peak top in the range of 80 to 130 ° C.
(2) The presence or absence of the formation of a phase separation structure can be confirmed by X-ray diffraction pattern measurement using a toner powder X-ray diffractometer. This is because in the case of the toner of the present invention, the polyester resin A having crystallinity is present in the toner in a state separated from the amorphous polyester resin B while maintaining crystallinity. The assigned diffraction peak exists at a position of at least 2θ = 20 ° to 25 °. When the phase separation structure is not formed, the crystalline structure of the crystalline polyester resin A is not maintained, and is compatible with the amorphous polyester resin B, so that a diffraction peak attributed to the crystalline polyester resin A does not appear. .
Here, the measurement of the glass transition point (Tg) and the melting point in the present invention is specifically determined by the following procedure. Using Shimadzu TA-60WS and DSC-60 as measuring devices, the measurement was performed under the following measurement conditions.
Measurement conditions Sample container: Aluminum sample pan (with lid)
Sample amount: 5mg
Reference: Aluminum sample pan (alumina 10mg)
Atmosphere: Nitrogen (flow rate 50ml / min)
Temperature conditions Starting temperature: 20 ° C
Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
Holding time: None Temperature drop: 10 ° C / min
End temperature: 20 ° C
Holding time: None Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
The measurement results were analyzed using the data analysis software (TA-60, version 1.52) manufactured by Shimadzu Corporation.
The analysis method is to specify a range of ± 5 ° C centering on the point showing the maximum peak on the lowest temperature side of the DrDSC curve, which is the DSC differential curve of the second temperature rise, and use the peak analysis function of the analysis software to determine the peak temperature. This is determined as the melting point.
Next, the maximum endothermic temperature of the DSC curve is determined using the peak analysis function of the analysis software in the range of the peak temperature + 5 ° C. and −5 ° C. in the DSC curve. The temperature shown here corresponds to the Tg of the toner.
The softening temperature [T (F1 / 2)] uses an elevated flow tester CF-500 manufactured by Shimadzu Corporation, die diameter: 0.50 mm, die length: 1.0 mm, load 10 kgf / cm ² , rate of temperature increase This is the melting temperature in the 1/2 method when a sample that has been pressed and shaped under a load of 30 kgf / cm ² under the condition of 3 ° C./min is melted out. For example, an elevated flow tester CFT500 type manufactured by Shimadzu Corporation is there. The flow curve of this flow tester becomes the data shown in FIGS. 5A and 5B, from which each temperature can be read.
In the figure, Ts is the softening temperature, Tfb is the outflow start temperature, and the melting temperature in the 1/2 method corresponds to the softening point of the present invention.
<< Measurement Conditions >> Load: 30 kgf / cm ² , Temperature rising rate: 3.0 ° C./min,
Die diameter: 0.50 mm, Die length: 1.0 mm
still,
In FIG. 5 (a),
A to B: Softened region (region in which the sample is deformed while being compressed and the internal gap is reduced)
B: Softening temperature Ts (temperature at which the gap disappears to form a single transparent body or phase with uniform appearance)
B to C: Stop region (region where there is no clear fluctuation in the position of the plunger)
C: Outflow start temperature Tfb or melting temperature Tfb (temperature at which the plunger clearly starts to fall)
C-D-E; Outflow area (area where the sample clearly flows out of the nozzle)
In FIG. 5B, X: Plunger position change amount Smax− in the outflow region [C to D in FIG. 5A]
The half value of Smin is shown.

(Crystalline polyester A)
The crystalline polyester resin A used in the present invention is characterized by comprising a crystalline aliphatic polyester resin containing an ester bond represented by the following general formula (1) in its molecular main chain.
_{-OOC-R-COO- (CH 2} ) n - (1)
In the above formula, R represents a linear unsaturated aliphatic divalent carboxylic acid residue, and is a linear unsaturated aliphatic group having 2 to 20 carbon atoms, preferably 2 to 4 carbon atoms. n is an integer of 2 to 20, preferably 2 to 6.
Presence of the structure of the general formula (1) can be confirmed by solid C ¹³ NMR (nuclear magnetic resonance analysis).
Specific examples of the linear unsaturated aliphatic group include linear unsaturated divalent carboxylic acids such as maleic acid, fumaric acid, 1,3-n-propene dicarboxylic acid, and 1,4-n-butenedicarboxylic acid. Mention may be made of linear unsaturated aliphatic groups derived from acids.
In the general formula (1), (CH ₂ ) _n represents a linear aliphatic dihydric alcohol residue.

Specific examples of the linear aliphatic dihydric alcohol residue in this case include linear aliphatic 2 such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Those derived from dihydric alcohols can be indicated. Since the polyester resin A uses a linear unsaturated aliphatic dicarboxylic acid as an acid component, the polyester resin A exhibits an effect that a crystal structure is easily formed as compared with the case where an aromatic dicarboxylic acid is used.
Polyester resin A is a polyvalent carboxylic acid component comprising (i) a linear unsaturated aliphatic divalent carboxylic acid or a reactive derivative thereof (an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, an acid halide, etc.) And (ii) a polyhydric alcohol component composed of a linear aliphatic diol can be produced by a polycondensation reaction by a conventional method. In this case, a small amount of other polyvalent carboxylic acid can be added to the polyvalent carboxylic acid component as necessary. In this case, the polyvalent carboxylic acid includes (i) an unsaturated aliphatic divalent carboxylic acid having a branched chain, (ii) a saturated aliphatic divalent carboxylic acid, and a saturated aliphatic trivalent carboxylic acid. In addition to polyvalent carboxylic acids, (iii) aromatic polyvalent carboxylic acids such as aromatic divalent carboxylic acids and aromatic trivalent carboxylic acids are included. The addition amount of these polyvalent carboxylic acids is usually 30 mol% or less, preferably 10 mol% or less, based on the total carboxylic acid, and is appropriately added within the range where the resulting polyester has crystallinity.

Specific examples of polyvalent carboxylic acids that can be added as needed include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, etc. A divalent carboxylic acid of: trimetic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, And trivalent or higher polyvalent carboxylic acids such as 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid, etc. it can.
A trivalent or higher polyhydric alcohol can be added to the polyhydric alcohol component, if necessary, in addition to a small amount of an aliphatic branched dihydric alcohol or cyclic dihydric alcohol. The addition amount is 30 mol% or less, preferably 10 mol% or less, based on the total alcohol, and is appropriately added within the range in which the resulting polyester has crystallinity.

Examples of polyhydric alcohol added as needed include 1,4-bis (hydroxymethyl) cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin and the like.
In the crystalline polyester resin A, the molecular weight distribution is preferably sharp from the viewpoint of low-temperature fixability, and the molecular weight is preferably a relatively low molecular weight. As for the molecular weight of the polyester resin A, the weight average molecular weight (Mw) is 5500-6500 in the molecular weight distribution by GPC (gel permeation chromatograph, a kind of liquid chromatograph) soluble in o-dichlorobenzene. The number average molecular weight (Mn) is preferably 1300 to 1500 and the Mw / Mn ratio is preferably 3.7 to 5.0.

The molecular weight distribution of the polyester resin A is based on a molecular weight distribution chart in which the horizontal axis is log (M: molecular weight) and the vertical axis is weight%. In the case of the polyester resin A used in the present invention, in this molecular weight distribution diagram, it is preferable to have a molecular weight peak in the range of 3.5 to 4.0 (% by weight), and the half width of the peak is 1.5 or less. Preferably there is.
In the crystalline polyester resin A, the glass transition temperature (Tg) and the softening temperature [T (F1 / 2)] are desirably low so long as the heat resistant storage stability of the toner is not deteriorated. Is 80 to 130 ° C., preferably 80 to 125 ° C., and T (F1 / 2) is 80 to 130 ° C., preferably 80 to 125 ° C. When Tg and T (F1 / 2) are higher than the above ranges, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.
Whether or not the resin fine particles in the present invention have crystallinity can be confirmed by whether or not a peak exists in the X-ray diffraction pattern by the powder X-ray diffractometer. In the diffraction pattern of the polyester resin A having crystallinity used in the present invention, at least one diffraction peak is present at a position where 2θ is 20 ° to 25 °, and preferably 2θ is at least (i) 19 Diffraction peaks are present at positions of ° to 20 °, (ii) 21 ° to 22 °, (iii) 23 ° to 25 °, and (iv) 29 ° to 31 °.
The powder X-ray diffraction measurement was performed using a Rigaku Electric RINT1100, using a wide-angle goniometer under the conditions of a tube bulb with Cu and a tube voltage-current of 50 kV-30 mA.

(Amorphous resin B)
Any conventionally known resin can be used as the non-crystalline (non-crystalline) resin B used in combination with the polyester resin A having crystallinity as the binder resin. For example, styrene, α-methylstyrene, chlorostyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, Styrene resins such as styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, polyester resin, vinyl chloride resin, rosin modified maleic acid resin, phenol resin, There are epoxy resins, polyethylene resins, polypropylene resins, ionomer resins, polyurethane resins, silicone resins, ketone resins, xylene resins, petroleum resins, hydrogenated petroleum resins, and the like. Of these, styrene resins and polyester resins containing an aromatic compound as a component are preferred. Particularly preferred are polyester resins.
Amorphous polyester resin B is synthesized from a polyhydric alcohol and a polycarboxylic acid. As the polyhydric alcohol and polyhydric carboxylic acid, components used in the crystalline polyester resin A can be used, and besides these, there are alkylene oxide adducts of bisphenol A, isophthalic acid, terephthalic acid, and derivatives thereof.
These resins are not limited to single use but can be used in combination of two or more.

The molecular structure of the polyester resin is not limited, but in particular, the alcohol component is at least one of bisphenol A propylene oxide adduct and bisphenol A ethylene oxide adduct, and the acid component has an unsaturated double bond between carbons. It is desirable to contain at least fumaric acid, maleic acid and derivatives thereof.
When the acid component of the polyester resin A and the polyester resin B has an unsaturated double bond between carbons, the unsaturated double bond between the carbons of the polyester A and the carbons of the polyester resin B in the melt-kneading step in toner production. And the unsaturated double bond of the polyester, the polyester A and the polyester resin B are finely dispersed and mixed. This is because plasticization occurs partially at the interface between the domains of both resins. On the other hand, when either of polyester resin A and polyester resin B has no unsaturated double bond between carbons, partial oxidation is not performed, and polyester resin A domain offset (occurred as a hot offset phenomenon) and There is a problem that an offset of the polyester resin B domain (occurred as a cold offset phenomenon) easily occurs.
The molecular weight of the polyester resin B used in the present invention is such that the weight average molecular weight (Mw) is 3000 to 100,000, the number average molecular weight (Mn) is 1500 to 4000 in the molecular weight distribution by GPC of the tetrahydrofuran (THF) soluble component, and The Mw / Mn ratio is preferably 2-50.
The molecular weight distribution of the polyester resin B is based on a molecular weight distribution chart in which the horizontal axis is log (M: molecular weight) and the vertical axis is weight%. In the case of the polyester resin B used in the present invention, it is preferable to have a molecular weight peak in the range of 2.5 to 4.5 (% by weight) in this molecular weight distribution diagram.
In the polyester resin B, the glass transition temperature (Tg) and the softening temperature [T (F1 / 2)] are desirably low as long as the heat-resistant storage stability of the toner is not deteriorated. In general, the Tg is 45. It is -75 degreeC, Preferably it is 50-70 degreeC, The T (F1 / 2) is 90-150 degreeC, Preferably it is 90-130 degreeC. When Tg and T (F1 / 2) are higher than the above ranges, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.

(Release agent)
As the release agent used for the toner in the present invention, all known ones can be used, and in particular, the free fatty acid type carnauba wax, polyethylene wax, montan wax and oxidized rice wax can be used alone or in combination. . As the carnauba wax, those having fine crystallinity, an acid value of 5 or less, and a particle diameter of 1 μm or less when dispersed in a toner binder are preferable. The montan wax generally refers to a montan wax refined from minerals, and like a carnauba wax, it is microcrystalline and preferably has an acid value of 5 to 14. The oxidized rice wax is obtained by air-oxidizing rice bran wax, and the acid value is preferably 10-30. The reason is that these waxes are finely dispersed in the toner binder resin of the present invention, so that it is easy to obtain a toner excellent in offset prevention, transferability and durability as described later. These waxes can be used alone or in combination of two or more.
As other mold release agents, any conventionally known mold release agents such as solid silicone wax, higher fatty acid higher alcohol, montan ester wax, and polypropylene wax can be mixed and used.
The Tg of the release agent used in the toner of the present invention is preferably 70 to 90 ° C. If it is less than 70 ° C., the heat-resistant storage stability of the toner is deteriorated, and if it exceeds 90 ° C., the releasability at a low temperature is not expressed, the cold offset resistance is deteriorated, and the paper is wound around the fixing machine. The amount of these release agents used is 1 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the toner resin component. If it is less than 1% by weight, the effect of preventing offset is insufficient, and if it exceeds 20% by weight, transferability and durability are deteriorated.

Colorant:
As the colorant used in the color toner of the present invention, known pigments and dyes capable of obtaining toners of yellow, magenta, cyan and black colors can be used.
Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, and Tartrazine Lake. Be mentioned.
Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.
Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.
Examples of purple pigments include fast violet B and methyl violet lake.
Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.
Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.
These can use 1 type (s) or 2 or more types.

Charge control agent (CCA):
The color toner of the present invention can contain a charge control agent in the toner as needed.
For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), basic dyes such as C.I. I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Basic Green 4 (C.I. 42000) and the like and lake pigments of these basic dyes, C.I. I. Solvent Black 8 (CI. 26150), quaternary ammonium salts such as benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, or dialkyl tin compounds such as dibutyl or dioctyl, dialkyl tin borate compounds, guanidine derivatives, containing amino groups Polyamine resins such as vinyl polymers, condensation polymers containing amino groups, etc., Japanese Patent Publication No. 41-20153, Japanese Patent Publication No. 43-27596, Japanese Patent Publication No. 44-6397, Japanese Patent Publication No. 45-26478 Metal complex salts of the monoazo dyes described, salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr described in Japanese Patent Publication No. 55-42752 and Japanese Patent Publication No. 59-7385 , Fe, etc. Metal complex, a copper phthalocyanine pigment obtained by sulfonation, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like. Naturally, color toners other than black should avoid the use of charge control agents that impair the target color, and white metal salts of salicylic acid derivatives are preferably used.

Additive:
In the toner of the present invention, transferability and durability can be further improved by externally adding inorganic fine particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride, and resin fine particles to the base toner particles. it can.
This effect can be obtained by covering the wax that lowers transferability and durability with these external additives and reducing the contact area due to the toner surface being covered with fine particles. The surface of these inorganic fine particles is preferably subjected to a hydrophobic treatment, and metal oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment are preferably used. As the resin fine particles, polymethyl methacrylate or polystyrene fine particles having an average particle size of about 0.05 to 1 μm obtained by a soap-free emulsion polymerization method are suitably used. In addition, the combination of hydrophobized silica and hydrophobized titanium oxide increases the amount of hydrophobized titanium oxide externally added compared to the amount of hydrophobized silica externally charged. The toner can also be excellent in stability. In combination with the above-mentioned inorganic fine particles, silica having a specific surface area of 20 to 50 m ² / g and resin fine particles having an average particle diameter of 1/100 to 1/8 of the average particle diameter of the toner are conventionally used. The durability can be improved by externally adding an external additive having a particle size larger than that of the additive to the toner. This is because the metal oxide particles externally added to the toner tend to be embedded in the base toner particles in the process where the toner is mixed and stirred with the carrier in the developing device, charged, and used for development. This is because it is possible to prevent the metal oxide fine particles from being embedded by externally adding an external additive having a particle size larger than that of the oxide fine particles to the toner.

In addition, the above-mentioned inorganic fine particles and resin fine particles are contained (internally added) in the toner, but the effect is reduced compared with the case of external addition, but the effect of improving transferability and durability is obtained and the toner pulverization property is improved. Can be made. In addition, since external addition and internal addition can be used together to suppress embedding of externally added fine particles, excellent transferability can be stably obtained and durability can be improved.
In addition, the following are mentioned as a typical example of the hydrophobization processing agent used here. Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, Chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) ) Silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl Trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane, diventyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl -Dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl) -octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di- 3,3-dimethylpentyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane Dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl) -diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane , Hexatolyl disilazane and the like. In addition, titanate coupling agents and aluminum coupling agents can also be used. In addition, as an external additive for the purpose of improving cleaning properties, a lubricant such as an aliphatic metal salt or a fine particle of polyvinylidene fluoride can be used in combination.

(Particle size distribution)
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a weight average particle diameter of 3 to 8 μm. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent.
When the weight average particle diameter (D4) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur.
When the weight average particle diameter (D4) exceeds 8 μm, it is difficult to suppress scattering of characters and lines.
Moreover, it is preferable that ratio (D4 / D1) of a weight average particle diameter (D4) and a number average particle diameter (D1) exists in the range of 1.00-1.40.
The closer (D4 / D1) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

Next, a method for measuring the particle size distribution of toner particles will be described.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using first grade sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the weight and number of toner particles or toner using a 100 μm aperture as an aperture. Calculate weight distribution and number distribution. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 .35 to less than 8.00 μm; 8.00 to less than 10.08 μm; 10.08 to less than 12.70 μm; 12.70 to less than 16.00 μm; 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

Manufacturing method:
As a method for producing the toner of the present invention, a conventionally known method such as a melt kneading-pulverizing method or a polymerization method can be applied. The polymerization method is different from the other polymerization methods such as suspension polymerization method, emulsion polymerization method, dispersion polymerization method and the like, but other than dissolution suspension method, polymer suspension method, etc., extension reaction method and the like can be used.

Fixing device:
The fixing device will be described.
FIG. 1 is a diagram showing an example of a fixing device used for carrying out the present invention. Details have already been described in the background art, and will be omitted.
FIG. 2 is a diagram showing a fixing device used for carrying out the present invention. The fixing device 4 includes a fixing roller 31 and a heating roller 32 arranged opposite to each other, an endless fixing belt 33 stretched between the two rollers, and a pressure roller 34 that forms a nip N by being in pressure contact with the fixing belt 33. And a roller-shaped guide member 35 disposed at a position inside the annular conveyance path R of the fixing belt 33 and shifted to the transfer belt side. The fixing device 4 heats the fixing belt 33 by the heating roller 32, rotates the fixing belt 33 in the direction of arrow D, and carries it on the recording material S in the nip N formed by the fixing belt 33 and the pressure roller 34. The unfixed toner image t functions to be heated and melted and fixed on the recording material S. Here, the fixing roller 31, the heating roller 32, the pressure roller 34, and the roller-shaped guide member 35 are pivotally attached to a fixing device base frame fixed to the conveying unit side, and the respective rotation shafts are arranged in parallel to each other. . The conveyance guide member 29 is also supported by the fixing device base frame.
The base material of the fixing belt 33 is formed of a heat resistant resin. As the material of the heat resistant resin, polyimide, polyamideimide, polyetherketone (PEEK) or the like is used. The thickness of the substrate is preferably 30 to 100 μm from the balance between heat conduction and strength. Since the surface of the fixing belt 33 is in pressure contact with the recording material S and the unfixed toner image t, a surface layer excellent in releasability and heat resistance is required, and a surface release layer such as a fluororesin is coated It has been configured.
In order to obtain image uniformity, an elastic layer made of heat-resistant rubber such as 100-300 μm silicone rubber or fluoro rubber is provided under the surface release layer. The heating roller 32 is formed to be a thin metal roller having a diameter of φ20 to φ30 and made of Al or Fe and having a wall thickness ta of ta = 0.3 to 1.0 mm. As prepared. The temperature of the heating roller 32 is detected by the temperature control element 38, and the detected temperature information is output to the image processing unit, and the heating roller is controlled to have a preset constant temperature, whereby the fixing belt 33 is required. It plays the role of heating to temperature.
The heating roller 32 also serves as a tension roller, and is stretched by a tension spring (not shown) in the direction of a broken line arrow P1 in the drawing. The fixing roller 31 is formed to have a diameter of φ20 to φ30 and includes an elastic layer 312 made of a heat resistant elastic body such as foamed silicone rubber or liquid silicone rubber in order to obtain a nip width L on the outer periphery of the Fe metal core 311. . The thickness of the elastic layer 312 is about 3 to 6 mm. The surface hardness of the fixing roller 31 is about Asker C30 to 50 Hs (unit indicating rubber hardness).
The pressure roller 34 is formed by forming a heat-resistant elastic layer 342 such as fluorine-based rubber or silicone rubber and a surface release layer 343 made of fluorine-based resin on the outer periphery of a core metal 341 made of Fe or Al. In this embodiment, in order to improve the releasability between the recording material S and the toner, the surface hardness of the pressure roller 34 is made higher than that of the fixing roller 31, and both come into contact with each other between the fixing belt 33 and the pressure roller 34. A fixing nip N having a nip width L whose portion is curved downward is formed. In this embodiment, the thickness of the elastic layer 342 of the pressure roller 34 is about 0.5 to 2 mm, and the surface hardness thereof is Asker C70 to 90 Hs. In the pressure roller 34, it is desirable to provide a halogen heater 344 for accelerating the temperature rise of the pressure roller.
In the belt fixing device shown in FIG. 2, a roller press in which the fixing roller 31 and the pressure roller 34 are in contact with each other with the belt pressing portion a and the fixing belt 33 in contact with the fixing belt 33 wound around the pressure roller 34. A nip N having a relatively large nip width L composed of the pressure portion b is held. The same applies to FIG. 1, and a nip N having a relatively large nip width L is maintained.
Reference numerals 351 and 352 in FIG. 2 denote tension rollers and roller shafts of the fixing belt, which are used for fastening the belt.
FIGS. 3A and 3B show an example of a specific example of a heat source in the belt fixing device of the present invention.
FIG. 3A shows a heating belt heated by installing a radiant heat source inside the heating belt. On the other hand, FIG. 3-2 shows a case where a radiant heat source is installed outside the heating belt to heat the heating belt. About the installation position of such a radiant heat source, it can select according to the magnitude | size of an apparatus, the circumference of a heating belt, etc.
FIG. 3C shows an example of a heat source in the belt fixing device of the present invention, in which an induction heating source is used as the heat source. The heat source species can also be selected according to the size of the device and the required power of the device.
FIG. 4 shows an example of a roller fixing device, which was used in a comparative example for comparison with the belt fixing device used in the present invention.
Reference numeral 41 denotes a fixing roller, and 42 denotes a pressure roller. The fixing roller 41 is formed on the surface of a metal cylinder 43 made of a high thermal conductor such as aluminum, iron, stainless steel or brass, at room temperature vulcanization (RTV) silicon rubber, tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), poly An offset prevention layer 4 such as tetrafluoroethylene (PTFE) is coated. A heating lamp 45 is disposed inside the fixing roller 41. The metal cylinder 46 of the pressure roller 42 is often made of the same material as that of the fixing roller 41, and the surface thereof is covered with an offset prevention layer 47 such as PFA or PTFA. Further, although not always necessary, a heating lamp 48 is disposed inside the pressure roller 42. Although the fixing roller and the pressure roller are not shown, they are pressed against and rotated by springs at both ends. A fixing support S (transfer paper such as paper) of the toner image T is passed between the fixing roller 41 and the pressure roller 42 for fixing.

By implementing the present invention, it is possible to provide a full-color image forming method in which the rise time is short, the small particle size toner can be fixed at a low temperature, and there is no glossy abnormal image.
In addition, it is possible to provide a fixing device capable of fixing at a low temperature with a short rise time, and to provide a full-color image forming apparatus using the same without an abnormal image.

Hereinafter, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. All parts are parts by weight.
<Toner Production Example 1>
Crystalline polyester resin A1 15 parts Amorphous polyester resin B-H1 55 parts Amorphous polyester resin B-L1 30 parts Salicylic acid Zr salt (Hodogaya Chemical TN-105) 1 part Desorbed free fatty acid type carnauba wax (Tg: 83 5 parts Carbon black (Mitsubishi Chemical # 44) 10 parts The above toner constituent materials were sufficiently stirred and mixed in a Henschel mixer, and then melt-kneaded in a twin-screw extruder. Regarding the kneading conditions, as a result of setting the temperature of the kneader to knead the kneaded material at a low temperature (minimum temperature within the range where the kneaded material is in a molten state), the kneading material is mixed at the kneader outlet. The temperature of the kneader was set so that the temperature of the smelted product was 120 ° C.
Next, the kneaded product was coarsely pulverized to a particle size of 1 mm or less using an AP pulverizer manufactured by Hosokawa Micron Co., and then finely pulverized using a turbo mill manufactured by Turbo Industries Co., Ltd. to obtain a toner base having a weight average particle size of 6.5 μm.
The obtained toner base was classified, and 0.5 wt% of hydrophobic silica (average primary particle size 20 nm, bulk density 0.15 mg / cm ² ) and titanium oxide 0.3 wt% were added and mixed to obtain a final toner.
The toner SF1 is 159, SF2 is 160, and D4 / D1 is 1.21.
For toner SF1 and SF2,
The toner shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF1 increases.
The shape factor SF2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF2 = {(PERI) ² / AREA} × (100 / 4π) (2)
When the value of SF2 is 100, there is no unevenness on the toner surface, and as the SF2 value increases, the unevenness of the toner surface becomes more prominent.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco), and 100 particles were analyzed and calculated.

<Toner Production Example 2>
A toner was prepared in the same manner as in Toner Production Example 1 except that Polyester A1 was changed to Polyester A2 in Toner Production Example 1. The toner SF1 is 156, SF2 is 159, and D4 / D1 is 1.22.
<Toner Production Example 3>
A toner was prepared in the same manner as in Toner Production Example 1 except that Polyester A1 was changed to Polyester A3 in Toner Production Example 1. The toner SF1 is 157, SF2 is 158, and D4 / D1 is 1.20.
<Toner Production Example 4>
A toner was prepared in the same manner as in Toner Production Example 1 except that Polyester A1 was changed to Polyester A4 in Toner Production Example 1.
The toner SF1 is 160, SF2 is 163, and D4 / D1 is 1.22.
<Toner Production Example 5>
A toner was obtained in the same manner as in Toner Production Example 1 except that the de-free fatty acid type carnauba wax in Toner Production Example 1 was changed to polyethylene wax (Tg 110 ° C.). The toner SF1 is 159, SF2 is 160, and D4 / D1 is 1.21.
<Toner Production Example 6>
A toner was obtained in the same manner as in Toner Production Example 1 except that the de-free fatty acid type carnauba wax in Toner Production Example 1 was changed to polyethylene wax (Tg 58 ° C.). The toner SF1 is 158, SF2 is 161, and D4 / D1 is 1.19.
<Toner Production Example 7>
A toner was prepared in the same manner as in Toner Production Example 1 except that the weight average particle size of the finely pulverized toner base was 2.7 μm in Toner Production Example 1. The toner SF1 is 149, SF2 is 154, and D4 / D1 is 1.42.
<Toner Production Example 8>
A toner was prepared in the same manner as in Toner Production Example 1 except that the weight average particle size of the finely pulverized toner base was 9.0 μm in Toner Production Example 1. The toner SF1 is 163, SF2 is 166, and D4 / D1 is 1.10.

<Toner Production Example 9>
A toner was prepared in the same manner as in Toner Production Example 1 except that the formulation was changed to the following.
Crystalline polyester resin A1 60 parts Amorphous polyester resin B-H1 26 parts Amorphous polyester resin B-L1 14 parts Salicylic acid Zr salt (Hodogaya Chemical TN-105) 1 part Desorbed free fatty acid type carnauba wax (Tg: 83 5 parts Carbon black (Mitsubishi Chemical # 44) 10 parts The toner has SF1 of 154, SF2 of 159, and D4 / D1 of 1.22.

<Toner Production Example 10>
A toner was prepared in the same manner as in Toner Production Example 1 except that the formulation was changed to the following.
Crystalline polyester resin A1 0.5 part Amorphous polyester resin B-H1 64.5 parts Amorphous polyester resin B-L1 35 parts Salicylic acid Zr salt (Hodogaya Chemical TN-105) 1 part Desorbed fatty acid type carnauba wax (Tg: 83 ° C.) 5 parts Carbon black (Mitsubishi Chemical # 44) 10 parts The toner SF1 is 158, SF2 is 160, and D4 / D1 is 1.20.

<Manufacture of polyester A>
Polyesters A1 to A4 were charged with 4000 g of the composition shown in Table 1 and 4 g of hydroquinone in a 5 L four-necked round bottom flask equipped with a thermometer, stirrer, condenser and nitrogen gas inlet tube. Set in a heater, introduce nitrogen gas from the nitrogen gas inlet tube, raise the temperature in a state where the flask is kept in an inert atmosphere, and maintain at 160 ° C. for 5 hours, and then react at 200 ° C. for 1 hour. Each polyester was obtained by reaction at 8.3 kPa for 1 hour.
Table 1 shows components of each polyester A1 to A4, and Table 2 shows physical property values of each polyester A1 to A4.
BPA / EO shown in Table 1 represents an ethylene oxide adduct of bisphenol A (2.2 mol adduct), and BPA / PO represents a propylene oxide adduct of bisphenol A (2.2 mol adduct). Indicates.

(Note) Only polyester A2 has a weight ratio for both acid and alcohol components.

In addition, the thing with crystallinity is a diffraction peak in the position of at least 2 (theta) = 19-20 degrees, 21-22 degrees, 23-25 degrees, 29-31 degrees in the X-ray-diffraction pattern by a powder X-ray-diffraction apparatus. Appears. Those having an estimated molecular formula are those in which the presence of the molecular structure of the general formula (1) was confirmed by solid-state C ₁₃ NMR.

<Manufacture of polyester B>
For polyesters B-H1 and B-L1, 4000 g of the composition shown in Table 3 was placed in a 5 L four-necked round bottom flask equipped with a thermometer, stirrer and condenser, and this flask was set in a mantle heater. 4 g of dibutyltin oxide was added, the temperature was raised, the temperature was kept at 220 ° C., the reaction was carried out for 8 hours, and then the reaction was carried out at 8.3 kPa until a predetermined softening point was reached to obtain each polyester.
Table 3 shows each of the polyester B-H1 and B-L1 components, and Table 4 shows their physical property values.
BPA / EO shown in Table 3 represents an ethylene oxide adduct of bisphenol A (2.2 mol adduct), and BPA / PO represents a propylene oxide adduct of bisphenol A (2.2 mol adduct). Indicates.

<Example of carrier production>
(I) Core material: Cu—Zn ferrite particles (volume average diameter: 45 μm) 5000 parts (ii) Coating material Toluene 450 parts Silicone resin SR2400
(Toray Dow Corning Silicone, 50% nonvolatile content) 450 parts Aminosilane SH6020
(Toray / Dow Corning / Silicone) 10 parts Carbon black 10 parts The above coating material is dispersed with a stirrer for 10 minutes to prepare a coating liquid, and this coating liquid and core material are placed in a fluidized bed. The coating liquid was applied to the core material, and the coating liquid was applied to the coating material while coating while forming a swirling flow.
Next, the obtained carrier was baked in an electric furnace at 250 ° C. for 2 hours, and the carrier particles of the production example (saturation magnetization 65 emu / g when 3 kOe was applied, residual magnetization 0 emu / g when 3 kOe was applied, specific resistance 3.2). × 108 Ω · cm, volume average diameter 45 μm).

<Examples of developer production>
Developer (1) corresponding to each toner corresponding to Toner Production Examples 1 to 10 by mixing 2.5 parts of the toner of Production Examples 1 to 10 and 97.5 parts of the carrier of the above Production Examples with a tumbler mixer To (10) was obtained.

Evaluation method of resin physical properties Measurement of molecular weight by GPC (1) Measurement of molecular weight of polyesters B-H1, B-L1 and polyester A2 by GPC GPC-150C (manufactured by Waters) was used as a device in a 40 ° C. heat chamber. Stabilize the column, flow THF at a flow rate of 1 ml / min through the column at this temperature, and inject 0.1 ml of a THF sample solution of resin (sample concentration 0.05 to 0.6%). .
The THF sample solution of the resin was prepared by stirring a THF solution having a resin concentration of 0.5% by weight with a ball mill at room temperature for 24 hours, and then filtering with a 0.2 μm hole diameter membrane filter manufactured by Toyo Filter Paper Co., Ltd. is there. Waters GPC-150C can be used as a measuring device, and Shodex KF801-807 can be used as a column. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Or Toyo Soda Kogyo Co., Ltd. having a molecular weight of ^{6 × 10 2, 2.1 × 10} 3, 4 × 10 3, 1.75 × 10 4, 5.1 × 10 4, 1.1 × 10 5, 3.9 It is suitable to use x10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.
(2) Measurement of molecular weight by GPC of polyesters A1 and A3 to A4 GPC is measured as follows.
The column was stabilized in a heat chamber at 145 ° C., and o-dichlorobenzene containing 0.3% dibutylhydroxytoluene (BHT) was flowed as an eluent at a flow rate of 1 ml / min. Measure by injecting 50-200 μl of 140 ° C. o-dichlorobenzene solution of resin prepared to 3 wt%. Waters 150CV type can be used as a measuring instrument, and Shodex AT-G + AT-806MS (two) can be used as a column.

Molecular structure of resin Using solid C13-NMR (FT-NMR SYSTEM JNM-α400 manufactured by JEOL Ltd.), observation nucleus C13, reference material adamantane, accumulated number 8192 times, pulse series CPMAS. IRMOD: IRLEV, observation frequency 100.4 MHz, OBSET: 134500 Hz, POINT: 4096, PD: 7.0 sec, SPIN 6088 Hz, and molecular structure estimation is performed by Chem Draw Pro Ver. 4.5.
The following two measurements were used in combination to confirm the results of molecular structure analysis by solid C13-NMR.
(A) A sample is measured by a Fourier transform infrared spectrophotometric (FT-IR) transmission method, and the structure is estimated from standard spectrum comparison.
Measuring machine: Nicolet Magna 850
Measurement range: 4000 to 400 cm ⁻¹
Standard sample: KBr
(B) Structure estimation of pyrolyzable organisms using pyrolysis gas chromatogram mass spectrometer Measuring instrument: Shimadzu Corporation GC-17A, Shimadzu CR-4A
Thermal decomposition temperature: Nippon Analytical Industry JHB-3S
Thermal decomposition temperature: sample heating temperature × time is 590 ° C. × 4 seconds Column: DB-5 (J and W Co.) L = 30 m, I.V. D = 0.2
5mm, Film = 0.25mm
Column temperature: raised from 50 ° C. (holding time 1 minute) to 300 ° C. at 10 ° C./min. Injection temperature: 320 ° C.
Carrier gas pressure: From 90 kPa (holding time 2 minutes) to 2 kPa / min, 150
Boost to kPa Detector: FID

The evaluation methods and conditions in the examples are shown below.
As the fixing machine, the fixing machine 1 and the fixing machine 2 having the following configurations were used.
Fixing machine 1
Fixing machine: In the fixing machine of FIG. 2, a fixing device having the following specifications was used.
Fixing belt 33: base polyimide, thickness 50 μm, elastic layer silicone rubber, thickness 250 μm, surface release layer PTFE
Heating roller 32: Core metal Fe, φ25, thickness 0.6mm
Fixing roller 31: Core metal Fe, φ30, elastic layer foamed silicone rubber, thickness 4 mm, ASKerC 40HS
Pressure roller 34: core metal Fe, φ30, elastic layer silicone rubber, thickness 1.5mm, ASKER C 80HS, surface release layer PTFE
Fixing machine 2
The Ricoh copier Imagio Neo 350 was modified so that the original fixing device can be removed and another fixing device can be attached to change the set temperature of the fixing device. The toner, developer, fixing machine, and Ricoh type 6200 paper shown in the examples were set on this, and a copy test was conducted.
The fixing device used for the evaluation is the heat roller fixing device shown in FIG. 4 and has the following configuration.
The metal cylinder of the fixing roller is SUS and has a thickness of 3.0mm
The offset prevention layer of the fixing roller is made of PTFE and has a thickness of 20μm.
The metal cylinder of the pressure roller is 2mm thick with SUS
The pressure roller offset prevention layer is 50 μm thick PFA on 4 μm thick silicon rubber.

Glossiness evaluation method:
Adjustment was made so that 1.0 ± 0.1 mg / cm ² of toner was developed, and the glossiness of the solid image sample when the surface temperature of the fixing roller was 160 ° C. was determined by a gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. Was measured under the condition of an incident angle of 60 °.
The transfer paper used was Ricoh full color PPC paper type 6000 <70W. As the glossiness is higher, the glossiness is higher, and a glossiness of about 10% or more is required to obtain a clear image with excellent color reproducibility.

Offset property evaluation method:
The temperature of the fixing roller was changed by 5 ° C., and the temperature at which offset started to occur was measured. The fixing roller was evaluated under the condition that no oil was applied, and the transfer paper was Ricoh Full Color PPC paper type 6000 <70 W. The evaluation results were expressed as follows.
Low temperature fixability:
The fixing temperature was changed by the same method as the evaluation of the offset property, and a copy image was obtained such that the image density by the Macbeth densitometer was 1.2.
The copy image at each temperature was rubbed 10 times with a clock meter equipped with a sand eraser, the image density before and after that was measured, and the fixing rate was determined by the following formula.
Fixing rate (%) = (Image density after 10 times of sand eraser) / (Previous image density) × 100
The temperature at which a fixing rate of 70% or more was achieved was defined as the minimum fixing temperature.
Table 5 shows toners and fixing conditions of Examples and Comparative Examples.

The evaluation results are shown in Table 6.

FIG. 2 is a diagram illustrating an example of a fixing device used in the practice of the present invention. FIG. 2 is a diagram illustrating a fixing device used for carrying out the present invention. FIG. 2 is a diagram illustrating a fixing device used for carrying out the present invention. FIG. 2 is a diagram illustrating a fixing device used for carrying out the present invention. It is a figure which shows an example of the specific example of a heat source among the belt fixing apparatuses of this invention. FIG. 3 is a diagram illustrating an example of a fixing device used in a comparative example. It is a figure which shows the flow curve of a flow tester, Comprising: (a) is a figure which shows the relationship between the melting temperature of a sample, and a piston stroke, (b) is a figure which shows the relationship between the melting temperature in a 1/2 method, and a piston stroke. .

Explanation of symbols

4 fixing device 31 fixing roller 32 heating roller 33 fixing belt 34 pressure roller 35 guide member g nip inlet t unfixed toner N nip A portion where the fixing roller and the pressure roller contact C portion wound around the pressure roller R Fixing belt transport path S Recording paper 41 Fixing roller 42 Pressure roller 43 Metal cylinder 44 Offset prevention layer 45 Heating lamp 46 Metal cylinder 47 Offset prevention layer 48 Heating lamp T Toner image W Adhesive support

Claims (13)

In a belt fixing type image forming method in which multicolor images are formed by superimposing different color toner images, the fixing nip time is 30 to 100 msec, the fixing pressure is 0.5 to 3 kgf / cm ² , and An image forming method, wherein the toner is a toner containing at least crystalline polyester A and amorphous resin B as binder resins.   The fixing device includes an endless fixing belt stretched between a fixing roller and a heating roller, and a pressure roller provided to face the fixing roller via the fixing belt, and at least the fixing belt is attached to the pressure roller. 2. An unfixed toner image carried on a recording material is heated and pressed by a nip composed of a wound portion and a portion where a fixing roller and a pressure roller are in contact with each other with a fixing belt interposed therebetween. The image forming method described.   The fixing device is disposed inside the fixing belt conveyance path and bends the conveyance path, and has a guide member that increases the tension of the fixing belt at the nip entrance, and the fixing member reaches between the pressure roller and the guide member. The image forming method according to claim 1, wherein the belt is stretched apart from the pressure roller.   The belt heating means has a configuration in which a radiant heating source or an induction heating heat source is provided as a heat source in either or both of the inside and outside of the heating belt. Image forming method.   The image forming method according to claim 1, wherein the belt heating unit has a configuration in which a radiation heat source is provided in at least the conveyance roller among the pressure roller and the conveyance roller.   The image forming method according to claim 1, wherein the glass transition point of the polyester resin A is in the range of 80 to 130 ° C.   The image forming method according to claim 1, wherein the content of the polyester resin A in the binder resin is 1 to 50% by weight.   The alcohol component constituting the polyester resin A consists of at least one selected from 1,4-butanediol and 1,6-hexanediol, while the acid component constituting the polyester resin A is maleic acid and fumaric acid The image forming method according to claim 1, comprising at least one selected from the group consisting of:   The image forming method according to claim 1, wherein the acid component constituting the amorphous polyester B comprises at least one selected from maleic acid and fumaric acid.   The toner according to claim 1, wherein the toner is an electrostatic charge developing toner containing a releasing agent, and the releasing agent has a glass transition point of 70 to 90 ° C. Image forming method.   The image according to any one of claims 1 to 10, wherein the release agent is one or more selected from a desorbed fatty acid type carnauba wax, a polyethylene wax, a montan wax, and an oxidized rice wax. Forming method.   The toner used has a weight average particle diameter of 3 to 8 μm and a ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) is in the range of 1.00 to 1.40. The image forming method according to claim 1, wherein: An image forming apparatus used in the image forming method according to claim 1.