JP2754539B2 - One-component development method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-magnetic one-component developing method using a one-component developer. (Prior Art) One-component developing methods include, for example, a dielectric developing method described in US Pat. No. 3,909,258, a touch-down method described in US Pat. No. 3,316,432, a charge developing method, a jumping method, and the like.
This is a development method using only a toner typified by an impression method, a powder cloud method, a fur brush method, and the like.It is possible to use a developing device having a simple configuration and to avoid deterioration of a developer in a two-component development method. Because it is easy and relatively good quality images can be obtained,
In recent years, research has been actively carried out and commercialized. In the one-component developing method, a developing device most frequently used at present has a toner layer formed and transported as shown in FIG. The regulation control of the toner layer includes a blade in FIG. 2A, a roll in FIG.
(C) is performed with a magnetic brush. (Problems to be Solved by the Invention) However, in the one-component developing method, since no carrier is used, formation of a uniform toner layer related to supply of the toner to the electrostatic latent image surface, control of conveyance, and further control of the toner There are problems such as difficulty in providing sufficient charge and controlling. For example, when the developing device shown in FIG. 2 is used,
In many cases, charge is applied by contact charging and frictional charging between the layer regulating member 7 and the toner carrier 5, but in order to impart sufficient charge to the toner 4, the toner must be stably formed in a thin layer. is required. However, no matter how thin the toner layer is, the charging efficiency is low as compared with the two-component development method using a carrier, and disadvantages such as uneven charging occur between toners. Unevenness, bleeding, fogging and the like often occur. In order to improve the chargeability, it is common to add a fluidizing agent such as colloidal silica to the toner and to use it in a state where the powder characteristics are controlled. However, the above disadvantage has been sufficiently solved. Not in. The present invention has been made in view of the above problems in the related art. Accordingly, it is an object of the present invention to provide a non-magnetic one-component developing method capable of obtaining a clear image faithful to an original. Another object of the present invention is to provide a non-magnetic one-component developing method in which toner is formed in a thin layer on a toner carrier and has sufficient developability. (Means for Solving the Problems) As a result of the study, the present inventors have found that the amount of toner transported on the toner carrier and the developability are affected by the adhesion of the toner to the toner carrier. And two specific fine powders smaller than the particle size of the toner particles, namely, SiO ₂ ,
When using a developer in which a fine powder having a relatively small particle diameter and a fine powder having a relatively large particle diameter selected from SnO ₂ , TiO ₂ , ZrO ₂ , ZnO and Al ₂ O ₃ are externally mixed, the toner carrier The present inventors have found that the above-mentioned transport amount, charge amount, and developability are all satisfied, and have completed the present invention. The present invention uses a non-magnetic one-component developing device having at least a developer-carrying roll and a layer-forming member to supply a developer to a photoreceptor and to visualize an electrostatic latent image on the photoreceptor. In the one-component developing method, as a developer, toner particles, smaller than the toner particles, and SiO ₂ , SnO ₂ , Ti
O ₂ , ZrO ₂ , ZnO and Al ₂ O ₃ using a mixture of two types of fine powder having an average particle diameter different from each other externally added, the transport amount on the developer carrying roll is 0.5 to 0.75 mg / cm ² . In the developing step in the electrophotographic method of the present invention, the toner generates an appropriate triboelectric charge with the blade surface, and furthermore, in order to obtain an extremely thin uniform toner layer of one or two layers according to the toner particle size, it is necessary to individually The toner particles must have appropriate fluidity and have an appropriate adhesion to the toner carrier. If a toner having too small an adhesive force is used, the above-described toner layer having a uniform thickness is not formed, and the image density is low and image unevenness is likely to occur. On the other hand, if the adhesive force is too large, the toner layer on the toner carrier becomes thick, so that the frictional charge with the blade is insufficient and the amount of the opposite polarity toner increases. When such a toner is developed, background stain or bleeding due to the opposite polarity toner, and the fidelity reproducibility of the fine line becomes insufficient. Factors related to the adhesion of the toner to the toner carrier include numerous physical conditions such as toner particle size, shape, electrostatic properties, degree of compression, and temperature of adsorbed water. Has provided a non-magnetic one-component developing method free from the above-mentioned drawbacks, focusing on fine powder externally added to and mixed with the toner. Hereinafter, the non-magnetic one-component developing method of the present invention will be described in detail. FIG. 1 is a schematic sectional view of an example of a non-magnetic one-component developing device used in the present invention. In FIG. 1, a developing machine main body 2 installed near an electrostatic latent image holding member 1 has a hopper 3 having an opening on the electrostatic latent image holding member 1 side. A toner carrier 5 is accommodated in the lower portion of the hopper 3 and partially projects from the opening toward the electrostatic latent image carrier 1. The toner carrier 5 is made of a roll or belt having a smooth surface or moderate irregularities,
It is rotated, for example, in the direction of the arrow by a drive system not shown. Further, a DC and / or AC bias voltage is applied by a bias power supply 6 as needed. Further, the toner carrier 5 is provided with a mechanical layer regulating member for uniformly controlling the application of the toner particles in one or two thin layers. The layer regulating member 7 is composed of a blade, a roll, a brush, and the like, and can perform charging of the toner 4 and contact charge, friction and the like together with layer regulation. Further, the toner charge can be adjusted by ion irradiation or the like. In this case, it is preferable to use a material for the layer regulating member 7 that is located at a position that is appropriately separated from the toner 4 on the charging line. A DC and / or AC power supply 8 is connected to the layer regulating member 7 as necessary, so that an electric field is generated between the toner carrier 5 and the layer regulating member 7. This electric field is applied to the toner carrier 5
By transmitting a minute vibration to the toner 4 sandwiched between the toner and the layer regulating member 7, it is possible to prevent a decrease in the fluidity of the toner,
In addition to being advantageous for forming a uniform thin toner layer on the toner carrier, it is sometimes advantageous in that it can exert an amplifying action or a charge injecting action at the time of applying a charged charge by the above-mentioned contact or friction. The toner 4 having a layer formed in an ultra-thin layer by the layer regulating member 7 is carried and conveyed on the toner carrier 5 by electrostatic attraction such as a mirror image force and a polarization force and / or Van der Waals force, and reaches the developing area. Is in contact with the electrostatic latent image holding member 1 or in a non-contact manner with a small gap. In this way, the toner 4 is charged by the electrostatic latent image 9 and an electric field formed between the toner carrier 5 of the electrostatic latent image holder 1 by the DC and / or AC bias voltage applied as needed. Adhesive development is performed according to the image pattern. In the present invention, in the non-magnetic one-component developing device, the toner is charged mainly by the layer regulating member 7,
Further, the toner carrier 5 is controlled so as to be uniformly applied in one or two thin layers. The toner is conveyed to a position facing the electrostatic image while being electrostatically attached to the toner carrier, and is developed. As a result, an image having excellent dot reproducibility can be obtained. The developer used in the present invention is composed of toner particles and two types of fine powder as described above. The toner particles have an average particle diameter of 7 to 15 μm and are mainly composed of a colorant and a binder resin. As the binder resin, styrene resin, acrylic resin, olefin resin such as polyethylene, polybutadiene, diene resin such as polyisoprene, polyester,
Synthetic resins such as epoxy resins, fluororesins, silicone resins, phenolic resins, petroleum resins, and polyurethanes, as well as natural resins can be used. Known dyes and pigments can be used as the colorant. For example, carbon black, magnetite,
Nigrosine dye, aniline blue, chrome yellow, ultramarine, methylene blue chloride, phthalocyanine blue, disazo yellow, magenta dye and the like can be used. Further, when it is necessary to control the chargeability of the toner, a known charge control agent can be contained. For example, as the negative charge control agent, a metal chelate such as a metal-containing dye, an acidic or electron-withdrawing organic substance, and as the positive charge control agent, nigrosine, a quaternary ammonium salt, or another basic electron donating agent. Organic substances and the like can be used. In addition, an inorganic substance such as a metal oxide and an inorganic substance whose surface is treated with the organic substance can also be used. The two types of fine powders having different average particle diameters externally added to the toner particles include SiO ₂ , SnO ₂ , TiO ₂ , ZrO ₂ , and Zn.
An inorganic fine powder selected from O and Al ₂ O ₃ is used. Both of these two types of fine powder need to be smaller than the particle size of the toner particles. The average particle size of these two types of fine particles is 0.02 μm or less for one, and 0.03 μm for the other.
It is preferably from 1 μm to 1 μm, in which case the characteristics in the development step are maximized. If the average particle size of one of the fine powders is larger than 0.02 μm, the adhesive force decreases, and it becomes difficult to transport the toner onto the toner carrier. When the average particle size of the other fine powder is smaller than 0.03 μm,
When the toner adhesion cannot be sufficiently reduced and the developing property is insufficient, and when the particle diameter is larger than 1 μm, the fine powder detaches from the toner at an early stage, and becomes more contained in the toner layer on the toner carrier. Then, a phenomenon occurs in which layer unevenness or spillage occurs. Therefore, the average particle size of the two types of fine powder is preferably set in the above range. The toner used in the present invention may be manufactured by any known method such as a kneading method and a pulverizing method. Fine powder externally added to the toner is also added by a known method. In the non-magnetic one-component developing method of the present invention, the layer regulating member 7 is mainly used.
Therefore, in order to uniformly charge the toner, the toner needs to form a thin and uniform layer on the toner carrier. The amount of toner transported varies depending on the average particle size of the toner, but the amount of toner transported on the toner carrier is generally in the range of 0.5 to 0.75 mg / cm ² . Further, the developability of the toner is affected by the adhesion of the toner to the toner carrier. Experimentally, the lower the adhesion of the toner to the toner carrier, the better the developability. The present inventors have paid attention to the surface state of the toner, and have studied the toner carrying amount and the developing property of the toner carrier for various toners. However, the irregular toner (for example, When a fine powder, for example, fine silica fine powder (average particle size 0.02 μm or less) is externally added to (average particle size 12 μm), the image density is low and the background portion is not stained because of poor developability. On the other hand, a fine powder having a larger average particle size, for example, a silica powder (average particle size of 0.04 μm or more) externally added to the same toner has a uniform layer and good developability. Since the toner transport amount is small, a sufficient image density cannot be obtained. However, when these two kinds of fine powders having different average particle diameters are used in combination, the action is unknown, but surprisingly, the above-mentioned disadvantages are improved, and the toner layer formed on the toner support is uniform. The transport amount is not small, the developability is good, and an image having a sufficient image density without contamination on the background can be obtained. Hereinafter, the present invention will be described with reference to examples. Example 1 Styrene / n-butyl methacrylate (70/30) copolymer (Mn: about 15,000, Mw: about 40000) 90 parts by weight Carbon black 9 parts by weight Metal-containing dye (EISEN SPILON BLACK TRH: Hodogaya Chemical Industry Co., Ltd.) 1 part by weight The above components were melt-kneaded by a roll mill, coarsely pulverized by a hammer mill, finely pulverized by an air jet method, and classified to obtain a toner having an average particle diameter of 12 μm. The following fine powder was added and stirred with a high-speed mixer to prepare a developer: Hydrophobic silica (R-972, average particle size 0.016 μm, manufactured by Nippon Aerosil Co., Ltd.) 1.0% by weight Hydrophobic silica (OX-50) Hydrophobized product, average particle size 0.04μ
m, manufactured by Nippon Aerosil Co., Ltd.) 1.0% by weight In the non-magnetic one-component developing apparatus shown in FIG. 1, the toner carrier 5 has graphite dispersed in phenol resin.
The electric resistance controlled to about 10 ¹⁰ Ω · cm was used.
Also, as the layer regulating member, a stainless steel thickness of 0.1 mm
A modified silicone rubber coated to a thickness of 1 mm on the blade of No. 1 was used. The layer regulating member was brought into contact with the toner carrier at a pressure of about 100 g / cm. This non-magnetic one-component developing apparatus was placed in an FX-2300 remodeled copying machine manufactured by Fuji Xerox Co., Ltd., and a voltage of 2.5 V AC with a frequency of 2.5 KHz superimposed with 400 V DC was applied to perform proximity development.
The obtained image had excellent resolution and clear image quality without fogging. Table 1 shows the state of layer formation of the developer, the transport amount on the toner carrier, the charging property, and the developing property. All evaluations in Table 1 were performed at room temperature and normal humidity (22 ° C, 55R
This was performed under the environment of H). The chargeability was evaluated by a charge amount measuring device (manufactured by Xerox) (for details, refer to JP-A-57-79958). Example 2 A developer was obtained under the same conditions as in Example 1 except that the amount of the fine powder added to the toner in Example 1 was changed as described below, and the characteristics were evaluated. Hydrophobic silica (R-972, average particle size 0.016 μm, manufactured by Nippon Aerosil Co., Ltd.) 0.5% by weight Hydrophobic silica (OX-50 hydrophobized product, average particle size 0.04 μm)
m, manufactured by Nippon Aerosil Co., Ltd.) 1.5% by weight The results are shown in Table 1. As is clear from the results in Table 1, when this developer was used, the developing characteristics were good, and the copied image was clear and free of fog. Example 3 A toner was prepared in the same manner as in Example 1,
The average particle size was 7 μm. The following fine powder was added to the toner, and stirred with a high-speed mixer to prepare a developer. Hydrophobic silica (R-972, average particle size 0.016 μm, manufactured by Nippon Aerosil Co., Ltd.) 1.75% by weight Hydrophobic silica (OX-50 hydrophobized product, average particle size 0.04 μm)
m, manufactured by Nippon Aerosil Co., Ltd.) 1.00% by weight Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1. As is evident from the results in Table 1, although the transport amount was slightly reduced and the charge amount was slightly increased due to the decrease in the toner particle size, the layer uniformity and the developability were extremely good. Was higher than that of Example 1. Example 4 A developer was obtained under the same conditions as in Example 1 except that the following fine powder to be added to the toner in Example 1 was used. Hydrophobic silica (R-972, average particle size 0.016 μm, manufactured by Nippon Aerosil Co., Ltd.) 1.0% by weight Titanium oxide (Oxide P25, average particle size 0.03 μm, manufactured by Nippon Aerosil Co., Ltd.) 0.5% by weight Was evaluated under the same conditions as in Example 1, and the results shown in Table 1 were obtained. As is evident from the results, both the transportability and the chargeability on the support were good, and the image quality was high with high density and clear without fogging. Example 5 A developer was obtained under the same conditions as in Example 1 except that the following was used as the fine powder to be added to the toner in Example 1. Hydrophobic silica (R-972, average particle size 0.016 μm, manufactured by Nippon Aerosil Co., Ltd.) 1.0% by weight Tin oxide (T-1, average particle size 0.4 μm, manufactured by Mitsubishi Metals Corporation) 0.5% by weight Developer described above Was evaluated under the same conditions as in Example 1, and the results shown in Table 1 were obtained. As is clear from the results, the developer had good characteristics, and the obtained image had clear image quality without fogging. Comparative Example 1 In Example 1, hydrophobic silica (average particle size 0.04 μm) was used.
A developer was prepared in the same manner except that m) was not used. When this developer was used and evaluated under the same conditions as in Example 1, the results shown in Table 1 were obtained. As is evident from the results, the quality of the obtained image was of low quality, and the background was contaminated. Comparative Example 2 In Example 1, the hydrophobic silica (average particle size 0.016 μm) was used.
A developer was prepared in the same manner except that m) was not used. When this developer was used and evaluated under the same conditions as in Example 1, the results shown in Table 1 were obtained. As is clear from the results, the obtained image had a low image density. Comparative Example 3 A developer was prepared in the same manner as in Example 5, except that the average particle size of tin oxide was changed from 0.4 μm to 2 μm and 2% by weight was externally added. Evaluation was carried out using this developer under the same conditions as in Example 1, and the results shown in Table 1 were obtained. As is clear from the result, the toner was not uniformly conveyed on the toner carrier, and the spill was severely generated. (Effect of the Invention) The present invention is, as a developer in the non-magnetic one-component developing method as described above, smaller than the toner particles, and, SiO _2,
Since two kinds of fine powders having different average particle diameters selected from SnO ₂ , TiO ₂ , ZrO ₂ , ZnO and Al ₂ O ₃ were externally added and mixed, the toner carrier was used in a non-magnetic one-component developing apparatus. A uniform toner layer is formed thereon, the charging efficiency is good, and the developing property is excellent. Therefore, the obtained image has high resolution, excellent image quality without bleeding and fogging.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of an example of a non-magnetic one-component developing device used to carry out the present invention, and FIG. 2 is a schematic diagram of a generally used one-component developing device. FIG. 4 is an explanatory diagram illustrating the configuration of FIG. DESCRIPTION OF SYMBOLS 1 ... Electrostatic latent image holding body, 2 ... Developing machine main body, 3 ... Hopper, 4 ... Toner 5, 5 ... Toner carrier, 6 ... Bias power supply, 7 ... Layer regulating member, 8 ... Power supply, 9 ... Static latent image.

Continued on the front page (72) Inventor Hirotaka Matsuoka 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside the Fujimatsu Rocks Takematsu Office (72) Inventor Takashi Imai 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fujimatsu Rocks Takematsu Office (72) ) Inventor Takeshi Hashimoto 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. Takematsu Office (56) References JP-A-57-179866 (JP, A) JP-A-59-17560 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 9/08

Claims (1)

(57) [Claims] A non-magnetic one-component developing method for supplying a developer to a photoreceptor and visualizing an electrostatic latent image on the photoreceptor using a non-magnetic one-component developing device having at least a developer carrying roll and a layer forming member In the above, as a developer, toner particles are smaller than the toner particles, and SiO ₂ , SnO ₂ , TiO ₂ , ZrO ₂ , Zn
A mixture of two types of fine powders having different average particle diameters selected from O and Al ₂ O ₃ externally added and mixed, and the transport amount on the developer carrying roll is in a range of 0.5 to 0.75 mg / cm ² Non-magnetic one-component developing method characterized by the above-mentioned. 2. 2. The developer according to claim 1, wherein a toner obtained by externally adding a fine powder having an average particle diameter of 0.02 [mu] m or less and a fine powder having an average particle diameter of 0.03 to 1 [mu] m is used as the developer. Non-magnetic one-component developing method.