JP2014235276A - Electrophotographic image forming method and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming method and an electrophotographic image forming apparatus, in which wear resistance of an electrophotographic photoreceptor in long-term use can be improved, image irregularity caused by a lubricant can be improved and slippage of a toner due to a cleaning failure can be suppressed.SOLUTION: In the electrophotographic image forming method, an electrophotographic photoreceptor used for the electrophotographic image forming method has a layered structure of at least an organic photosensitive layer and a protective layer, stacked in this order; and the protective layer comprises a crosslinking resin and particles containing tin atoms (Sn). A toner used for the electrophotographic image forming method is produced by adding an external additive to toner base particles comprising a binder resin and a colorant; and the external additive comprises an aliphatic alcohol compound having a weight average molecular weight in the range from 300 to 1,500 and a hydroxy value in the range from 20 to 170 mgKOH/g.

Description

  The present invention relates to an electrophotographic image forming method and an electrophotographic image forming apparatus. More specifically, the present invention relates to an electrophotographic image forming method and an electrophotographic image forming apparatus that improve the abrasion resistance of an electrophotographic photosensitive member in long-term use, image unevenness due to a lubricant, and toner slippage due to poor cleaning.

  In the electrophotographic method, an electrostatic latent image formed on the surface of an electrophotographic photosensitive member (electrostatic latent image carrier) is developed with toner containing a colorant, and the obtained toner image is transferred to the surface of a recording medium. By fixing this with a heat roll or the like, an image can be obtained. In this electrophotographic method, the toner (transfer residual toner) adhered to the photoconductor after transfer so that the above-described electrophotographic photoconductor (hereinafter also referred to as “photoconductor”) can form an electrostatic latent image again. ) Is removed (cleaned).

However, since the electrophotographic photosensitive member is cleaned, it has a problem that it is easily worn and deteriorated when used for a long time.
Therefore, the photoconductor is required to have high wear resistance so as to suppress deterioration during long-term use.

  Patent Document 1 discloses a technique for improving the wear resistance by providing a protective layer on the photoconductor and increasing its curability in order to suppress the wear of the photoconductor due to cleaning. Specifically, an electrophotographic image forming apparatus having a long life is provided by the constitution of a photoreceptor and a specific cleaning blade containing fluororesin particles and a polycarbonate resin having a biphenyl structure on the outermost surface layer.

  On the other hand, in order to improve the ease of toner removal (cleanability), particles having lubricity such as fatty acid metal salts are generally added to the toner as a lubricant. For example, Patent Document 2 discloses a technique for improving cleaning properties by adding a fatty acid metal salt to toner base particles.

  However, a photoconductor in which the hardenability of the protective layer is increased in order to increase the wear resistance has a low affinity with the fatty acid metal salt. For this reason, the fatty acid metal salt does not spread over the entire surface of the photoconductor, and the chargeability of the photoconductor becomes non-uniform, resulting in image unevenness and image streaks due to toner slipping due to poor cleaning. There is a problem of doing.

JP 2011-197107 A JP 2000-89502 A

  The present invention has been made in view of the above-described problems and situations, and the problem to be solved is to improve the wear resistance of the photoconductor in long-term use, to improve image unevenness due to a lubricant, and to prevent toner slipping due to poor cleaning. It is an object to provide an electrophotographic image forming method and an electrophotographic image forming apparatus that can be suppressed.

In order to solve the above problems, the present inventor provided a protective layer on the photoreceptor in the course of examining the cause of the above problems, and added a crosslinkable resin and particles containing tin atoms (Sn) to the protective layer. As a result, it was found that the wear resistance was improved, and the present invention was achieved.
That is, the said subject which concerns on this invention is solved by the following means.

1. An electrophotographic image forming method comprising a charging step, an electrostatic latent image forming step, a developing step, a transfer step, and a cleaning step,
The electrophotographic photosensitive member used in the electrophotographic image forming method has a configuration in which at least an organic photosensitive layer and a protective layer are laminated in this order,
The protective layer contains a crosslinked resin and particles containing tin atoms (Sn),
The toner used in the electrophotographic image forming method is obtained by adding an external additive to toner base particles containing a binder resin and a colorant, and the external additive has a weight average molecular weight in the range of 300 to 1500. And an aliphatic alcohol compound having a hydroxy value in the range of 20 to 170 mgKOH / g.

  2. 2. The electrophotographic image forming method according to item 1, wherein the crosslinked resin of the protective layer is a crosslinked resin obtained by polymerizing a polymerizable compound having an acryloyl group or a methacryloyl group.

3. Said particles containing tin atoms (Sn) is the first term or electrophotographic image according to paragraph 2, characterized in that a composite particle comprising at least consisting of SnO ₂ particles or at least SnO ₂ and BaSO ₄ Metropolitan Forming method.

  4). The electron according to any one of Items 1 to 3, wherein the tin atom (Sn) -containing particle is a particle treated with a surface treatment agent having a polymerizable functional group. Photographic image forming method.

  5. The electrophotographic image forming method according to any one of Items 1 to 4, wherein the protective layer contains melamine resin particles.

  6). 6. The electrophotographic image forming method according to any one of items 1 to 5, wherein the external additive contains a fatty acid metal salt.

7). An electrophotographic image forming apparatus using the electrophotographic image forming method according to any one of items 1 to 6,
At least a charging means, an exposure means, a developing means and a transfer means,
The electrophotographic photoreceptor used in the electrophotographic image forming apparatus has a configuration in which at least an organic photosensitive layer and a protective layer are laminated in this order,
The protective layer contains a crosslinked resin and particles containing tin atoms (Sn),
The toner used in the electrophotographic image forming apparatus is obtained by adding an external additive to toner base particles containing a binder resin and a colorant,
The external additive contains an aliphatic alcohol compound having a weight average molecular weight in the range of 300 to 1500 and a hydroxy value in the range of 20 to 170 mgKOH / g. .

An electrophotographic image forming method and an electrophotographic image forming apparatus capable of improving the wear resistance of a photoreceptor in a long-term use, improving image unevenness due to a lubricant, and suppressing toner slipping due to poor cleaning by the above-described means of the present invention. Can be provided.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  In order to suppress abrasion of the photoreceptor due to cleaning, the abrasion resistance is improved by providing a protection layer on the photoreceptor and adding a crosslinkable resin and particles containing tin atoms (Sn) to the protection layer. There was found. Further, the particles containing tin atoms (Sn) are treated with a surface treatment agent having a polymerizable functional group, thereby expressing and protecting a crosslinked structure between the crosslinkable resin and the particles containing tin atoms (Sn). The strength of the layer is increased and the wear resistance is significantly improved. Moreover, it turned out that abrasion resistance can be improved more from a filler effect by including a melamine resin particle.

On the other hand, in order to improve the cleaning properties of the toner, it is common practice to add particles having a lubricating property such as a fatty acid metal salt to the toner as a lubricant.
However, the fatty acid metal salt has low affinity with a photoconductor containing a crosslinkable resin and particles containing tin atoms (Sn) in the protective layer, and does not spread over the entire surface of the photoconductor. For this reason, there has been a problem that the chargeability of the photosensitive member becomes uneven, image unevenness occurs, and image streaks occur due to toner passing through due to poor cleaning.

  The aliphatic alcohol compound according to the present invention exhibits sufficient lubricity by having an appropriate hardness and polarity, and has a high affinity with particles containing tin atoms (Sn) contained in the protective layer. Cheap. In the toner according to the present invention, since the aliphatic alcohol compound is added as a lubricant (external additive), the toner can uniformly adhere to the photoreceptor. For this reason, the electrophotographic image forming method of the present invention can prevent image unevenness and image streaks. It was also found that the inclusion of a fatty acid metal salt at a certain ratio has a synergistic effect on lubricity and further improves the cleaning properties.

Sectional drawing for description which shows an example of a structure of the image forming apparatus of the charging roller system used for the image forming method of this invention Cross-sectional view for explaining an example of the configuration of the charging roller in the image forming apparatus shown in FIG. Sectional drawing for description which shows an example of a structure of the circular slide hopper coating device used for the manufacturing method of the photoreceptor of this invention FIG. 3 is a perspective sectional view of the circular slide hopper applicator shown in FIG.

  The electrophotographic image forming method of the present invention is an electrophotographic image forming method including a charging step, an electrostatic latent image forming step, a developing step, a transfer step, and a cleaning step, wherein the electrophotographic image forming step is performed. The electrophotographic photoreceptor used in the method has a structure in which at least an organic photosensitive layer and a protective layer are laminated in this order, and the protective layer contains a crosslinked resin and particles containing tin atoms (Sn), The toner used in the electrophotographic image forming method is obtained by adding an external additive to toner base particles containing a binder resin and a colorant, and the external additive has a weight average molecular weight in the range of 300 to 1500. And an aliphatic alcohol compound having a hydroxy value (also referred to as a hydroxyl value) in the range of 20 to 170 mgKOH / g. This feature is a technical feature common to the inventions according to claims 1 to 7.

  Further, the present invention has such an effect that it can improve the wear resistance of the photoreceptor in a long-term use, improve image unevenness due to the lubricant, and suppress toner slippage due to poor cleaning.

  As an embodiment of the present invention, it is preferable that the cross-linked resin of the protective layer is a cross-linked resin obtained by polymerizing a polymerizable compound having an acryloyl group or a methacryloyl group from the viewpoint of manifesting the effects of the present invention. Thereby, fundamentally high layer strength can be obtained, so that the durability of the protective layer can be improved.

Further, in the present invention, particles containing the tin atoms (Sn) is preferably a composite particle comprising at least consisting of SnO ₂ particles or at least SnO ₂ and BaSO ₄ Metropolitan. Thereby, the photoconductor according to the present invention can obtain high potential characteristics.

  Furthermore, in this invention, it is preferable that the particle | grains containing the said tin atom (Sn) are the particle | grains processed with the surface treating agent which has a polymerizable functional group. Thereby, the film strength of the protective layer can be sufficiently obtained, and the potential stability can be obtained, so that both high durability and potential characteristics can be achieved. Moreover, high dispersibility is obtained in the particles containing tin atoms (Sn) in the crosslinked resin.

  Furthermore, in the present invention, the protective layer preferably contains melamine resin particles. Thereby, the abrasion resistance of the photoreceptor can be further improved due to the filler effect.

  Furthermore, in the present invention, it is preferable that the external additive contains a fatty acid metal salt. Thereby, the cleaning property of the toner is further improved.

  The electrophotographic image forming method of the present invention can be suitably provided in an electrophotographic image forming apparatus. Accordingly, it is possible to provide an electrophotographic image forming apparatus capable of improving the abrasion resistance of the photoreceptor in a long-term use, improving image unevenness due to the lubricant, and suppressing toner slippage due to poor cleaning.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Outline of Electrophotographic Image Forming Method of the Present Invention)
The electrophotographic image forming method of the present invention is an electrophotographic image forming method including a charging step, an electrostatic latent image forming step, a developing step, a transfer step, and a cleaning step,
The electrophotographic photosensitive member used in the electrophotographic image forming method has a configuration in which at least an organic photosensitive layer and a protective layer are laminated in this order,
The protective layer contains a crosslinked resin and particles containing tin atoms (Sn),
The toner used in the electrophotographic image forming method is obtained by adding an external additive to toner base particles containing a binder resin and a colorant,
The external additive contains an aliphatic alcohol compound having a weight average molecular weight in the range of 300 to 1500 and a hydroxy value in the range of 20 to 170 mgKOH / g.
Specifically, a charging process for uniformly charging the photoreceptor using a charging roller, an exposure process for forming an electrostatic latent image by exposing the uniformly charged photoreceptor, and the electrostatic latent A developing process for developing the image with an electrostatic image developing toner (hereinafter also simply referred to as “toner”), which will be described in detail below, and a toner image obtained by the development is transferred onto a transfer material such as paper. A transfer step, and a cleaning step of cleaning the photosensitive member with a cleaning blade after transferring the toner image.

<Charging process>
In this step, the electrophotographic photosensitive member is charged. The charging method is not particularly limited, and may be a known method such as a charging roller method in which the electrophotographic photosensitive member is charged by a charging roller.

<Electrostatic latent image forming process>
In this step, an electrostatic latent image is formed on the electrophotographic photosensitive member (electrostatic latent image carrier).
The electrophotographic photosensitive member is not particularly limited, and examples thereof include a drum-shaped one made of an organic photosensitive member such as polysilane or phthalopolymethine.
The electrostatic latent image is formed, for example, by uniformly charging the surface of the electrophotographic photosensitive member with a charging unit and exposing the surface of the electrophotographic photosensitive member imagewise with an exposing unit.
The charging means and the exposure means are not particularly limited, and those generally used in electrophotography can be used.

<Development process>
The development step is a step of forming a toner image by developing the electrostatic latent image with a dry developer containing toner containing a binder resin.
The toner image is formed using a dry developer containing a toner containing a binder resin, for example, using a developing unit including a stirrer that frictionally stirs and charges the toner and a rotatable magnet roller. Is called.
Specifically, in the developing unit, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and is held on the surface of the rotating magnet roller, thereby forming a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrophotographic photosensitive member (electrostatic latent image carrier), a part of toner constituting the magnetic brush formed on the surface of the magnet roller is electronically attracted by an electric attractive force. Move to the surface of the photoconductor. As a result, the electrostatic latent image is developed with toner, and a toner image is formed on the surface of the electrophotographic photosensitive member.

(toner)
The toner according to the present invention is obtained by adding an external additive to toner base particles containing a binder resin and a colorant, and the external additive has a weight average molecular weight in the range of 300 to 1500 and a hydroxy group. It contains an aliphatic alcohol compound having a value in the range of 20 to 170 mg KOH / g. As a result, the present invention has the effects of improving the abrasion resistance of the photoreceptor in long-term use, improving image unevenness due to the lubricant, and suppressing toner slippage due to poor cleaning.
In the present invention, the external additive preferably contains a fatty acid metal salt. Thereby, the cleaning property of the toner is further improved.

[Toner Production Method]
The toner according to the present invention is one in which an external additive containing at least an aliphatic alcohol compound is added to toner particles, but the method for producing the toner particles is not particularly limited, and a kneading and pulverizing method, Known methods such as a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method may be mentioned.
Among these, it is preferable to employ the emulsion aggregation method from the viewpoints of uniformity of particle size, shape controllability, and ease of forming the core / shell structure, which are advantageous for high image quality and high charge stability.
In the emulsion aggregation method, a dispersion of fine particles of a binder resin (hereinafter also referred to as “resin fine particles”) dispersed by a surfactant or a dispersion stabilizer is used to form a toner particle composition such as fine particles of a colorant as necessary. The toner is mixed with the component dispersion liquid and aggregated by adding an aggregating agent until the desired toner particle size is obtained, and thereafter or simultaneously with the aggregation, the resin fine particles are fused together to perform shape control. A method of forming particles.
Here, the resin fine particles may optionally contain internal additives such as a release agent and a charge control agent, and are formed of a plurality of layers composed of two or more layers made of resins having different compositions. It can also be.
The resin fine particles can be produced, for example, by an emulsion polymerization method, a miniemulsion polymerization method, a phase inversion emulsification method, or the like, or can be produced by combining several production methods. When an internal additive is contained in the resin fine particles, it is preferable to use a miniemulsion polymerization method.
When the internal additive is contained in the toner particles, the resin fine particles may contain the internal additive, or a dispersion of the internal additive fine particles consisting of only the internal additive is separately prepared and the internal additive is added. The agent fine particles may be aggregated together when the resin fine particles are aggregated.
Further, when the toner particles are configured to have a core / shell structure, resin particles having different compositions may be added at a time difference during aggregation and aggregated.

An external additive is added to the obtained dried toner particles by a dry method in which an external additive containing an aliphatic alcohol compound is added and mixed, whereby the toner used in the electrophotographic image forming method of the present invention is added. Is manufactured.
As a mixing device for the external additive, various known mixing devices such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

(External additive)
The external additive of the present invention contains an aliphatic alcohol compound.
Further, the external additive of the present invention preferably contains a fatty acid metal salt.
In addition to the above, other external additives that improve the charging performance and fluidity of the toner may be contained. Specifically, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, and the like, composite oxide fine particles, organic fine particles, and the like can also be used.

(Aliphatic alcohol compound)
The aliphatic alcohol compound according to the present invention has a weight average molecular weight in the range of 300 to 1500 and a hydroxy value in the range of 20 to 170 mgKOH / g. As a result, it is possible to improve the wear resistance of the photoconductor during long-term use, improve image unevenness due to the lubricant, and suppress toner slippage due to poor cleaning.

(Method for producing aliphatic alcohol)
The production method of the aliphatic alcohol compound according to the present invention is not particularly limited, and a known method can be applied. Below, the industrially applicable example is concretely described about the manufacturing method of the aliphatic alcohol compound which concerns on this invention.

Industrially, a higher fatty acid is used as a raw material and synthesized by a chemical reduction method using lithium aluminum hydride (LiAlH ₄ ) or a direct hydrogenation of a higher fatty acid ester.
As fats and oils used here, animal and vegetable fats and oils such as palm oil, palm oil, palm kernel oil, soybean oil, rapeseed oil, beef tallow, lard and fish oil, and hardened oils thereof can be mentioned.
The fatty acid ester used here is obtained by transesterifying the above fat with an alcohol by a known method, or a carboxylic acid obtained from the above fat by a known method such as hydrolysis by an alcohol by a known method. And those obtained by esterification.

  As the alcohol used for transesterification or esterification, those having 18 or less carbon atoms are used from the viewpoint of esterification speed and production efficiency of higher alcohol. That is, those having 1 to 18 carbon atoms are preferred, those having 1 to 4 carbon atoms are more preferred, and those having 1 carbon atom are particularly preferably used. Specific examples include methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, dodecanol, octadecanol and the like.

  The above-mentioned fat or fatty acid ester is derived into a corresponding aliphatic alcohol by hydrogenation using a hydrogenation catalyst. The hydrogenation catalyst used here is not particularly limited, and a commonly known catalyst is used. Preferably, a copper-based catalyst such as copper, copper-chromite, copper-zinc, or copper-iron-aluminum is used. Examples thereof include a hydrogenation catalyst having a main component. Moreover, the form is not specifically limited, Any of a powder form and a tablet form may be sufficient.

Hydrogenation of fats and oils or fatty acid esters can be carried out in the presence of a hydrogenation catalyst by any reaction system of a liquid phase suspension bed or a fixed bed. In the case of a liquid phase suspension bed reaction, the reaction temperature is in the range of 130 to 350 ° C., preferably in the range of 180 to 300 ° C., and the hydrogen pressure is in the range of 980.7 kPa to 34.3 MPa (10 to 350 kg / cm ² ). Of these, the reaction time is preferably in the range of 9.8 to 24.5 MPa (100 to 250 kg / cm ² ), and the reaction time is in the range of 0.5 to 5 hours. The usage-amount of a catalyst is in the range of 0.1-60 mass% with respect to the fats and oils or fatty acid ester which are starting materials, Preferably it exists in the range of 0.5-10.0 mass%.

Further, when a fixed bed reaction method is employed, a molded catalyst is used. The reaction temperature is in the range of 130 to 300 ° C., preferably in the range of 160 to 270 ° C., and the reaction pressure is in the range of 9.8 kPa to 29.4 MPa (0.1 to 300 kg / cm ² ), preferably 2.0. It is in the range of ˜24.5 MPa (20 to 250 kg / cm ² ). Here, the liquid hourly space velocity (LHSV) is arbitrarily determined according to the reaction conditions, but considering productivity or reactivity, LHSV is preferably in the range of 0.5 to 5 (h ⁻¹ ).

The reactor used here is not particularly limited, and a generally known reactor is used. For example, in the case of a liquid phase suspension bed reaction method, a gas-liquid solid suspension bed and the like can be mentioned, and in the case of a fixed bed reaction method, a trickle reaction bed (gas-liquid cocurrent fixed bed) and the like can be mentioned.
In order to obtain the corresponding aliphatic alcohol from the reaction product obtained as described above, the catalyst may be further purified by filtration, distillation or the like.

  In addition, it is preferable that the weight average molecular weight of the aliphatic alcohol compound based on this invention exists in the range of 300-1500. Within this range, the hardness is suitable, the photoreceptor can be easily coated, and the cleaning property is improved. That is, when the molecular weight is 1500 or less, it is possible to avoid the fear that the aliphatic alcohol compound is too hard and does not act on the photoreceptor at all. Thereby, the fear that the cleaning performance is not improved can be avoided. Further, when the molecular weight is 300 or more, it is possible to avoid the possibility of filming on the photoreceptor due to insufficient strength of the aliphatic alcohol compound.

  In addition, the aliphatic alcohol compound according to the present invention preferably has a carbon number in the range of 20 to 100. Within this range, the hardness is suitable, the photoreceptor can be easily coated, and the cleaning property is improved. That is, when the carbon number is 100 or less, the fear that the aliphatic alcohol compound is too hard and does not act on the photoreceptor at all can be avoided. Thereby, the fear that the cleaning performance is not improved can be avoided. Further, when the number of carbon atoms is 20 or more, it is possible to avoid the possibility of filming on the photoreceptor due to insufficient strength of the aliphatic alcohol compound.

In addition, the aliphatic alcohol compound according to the present invention is preferably linear. When it has a branched chain or a cyclic group, it tends to cause filming on the photoreceptor.
The aliphatic alcohol compound according to the present invention preferably has a hydroxy value in the range of 20 to 170 mgKOH / g. Within these ranges, it has sufficient lubricity, high affinity with the protective layer, and excellent long-term wear resistance, good image quality, and uniform cleanability. That is, within this range, it is possible to prevent the affinity with the photoreceptor from being lowered and non-uniform adhesion, and as a result, it is possible to suppress photoreceptor wear, image unevenness, and deterioration in cleaning properties.

  The number average particle size of the aliphatic alcohol compound according to the present invention is preferably in the range of 1 to 20 μm, more preferably in the range of 2 to 10 μm. Within this range, the developer can be efficiently transferred to the photoreceptor, and the friction resistance of the photoreceptor can be improved. When the number average particle diameter of the aliphatic alcohol compound is 1 μm or more, it is possible to suppress an increase in adhesion to the toner particles. As a result, it is possible to suppress the aliphatic alcohol compound from behaving together with the toner particles even on the photoreceptor, thereby avoiding the possibility that the effect of improving the cleaning property cannot be exhibited. In addition, when the number average particle diameter of the aliphatic alcohol compound is 20 μm or less, it is possible to avoid the possibility that the aliphatic alcohol compound does not migrate to the photoreceptor. Thereby, the possibility that the aliphatic alcohol compound does not function as a lubricant can be avoided.

  The addition ratio of the aliphatic alcohol compound according to the present invention is preferably in the range of 0.01 to 2.0 parts by weight, more preferably 0.05 to 1.0 parts with respect to 100 parts by weight of the toner base particles. Within the range of parts by mass.

  When the addition ratio of the aliphatic alcohol compound is in the above range, the aliphatic alcohol compound contained in the toner is easily supplied stably on the photoreceptor. That is, when the addition ratio of the aliphatic alcohol compound is 0.01 parts by mass or more, it is possible to avoid the possibility that sufficient cleaning properties cannot be obtained. Further, when the addition ratio of the aliphatic alcohol compound is 2.0 parts by mass or less, it is possible to avoid the possibility that sufficient fluidity cannot be obtained in the toner.

(Measurement of hydroxy value of aliphatic alcohol compound)
The hydroxy value of the aliphatic alcohol compound is measured according to JIS K 0070-1992. Specifically, it is as follows.

1. Preparation of reagent Acetylation reagent (25 g of acetic anhydride is taken in a 100-ml volumetric flask, pyridine is added to make a total volume of 100 ml, and shaken well.)
Phenolphthalein solution 0.5 kmol / m ³ Potassium hydroxide ethanol solution

2. Measurement method (a) The aliphatic alcohol compound is precisely weighed in a flat bottom flask within a range of 0.5 to 6.0 g, and 5 ml of an acetylating reagent is added thereto using a pipette.
(B) Place a small funnel in the mouth of the flask and immerse the bottom of about 1 cm in a glycerin bath within a temperature range of 95-100 ° C. and heat. In order to prevent the temperature of the neck of the flask from rising due to the heat of the glycerin bath, a cardboard disc with a round hole in it is put on the base of the neck of the flask.
(C) After 1 hour, the flask is removed from the glycerin bath, and after standing to cool, 1 ml of water is added from the funnel and shaken to decompose acetic anhydride.
(D) Further, in order to complete the decomposition, the flask is heated again in a glycerin bath for 10 minutes, and after cooling, the funnel and the wall of the flask are washed with 5 ml of ethanol (95).
(E) A few drops of phenolphthalein solution is added as an indicator, and titrated with 0.5 kmol / m ³ potassium hydroxide ethanol solution, and the end point is when the indicator is light red for about 30 seconds.
(F) In the blank test, (a) to (e) are performed without adding the aliphatic alcohol compound (a).
(G) If the sample is difficult to dissolve, add a small amount of pyridine, or add xylene or toluene to dissolve.

The calculation formula is as follows.
A = [{(BC) × 28.05 × f} / S] + D
However,
A: Hydroxy value (mgKOH / g)
B: Amount (ml) of 0.5 kmol / m ³ potassium hydroxide ethanol solution used for the blank test
C: Amount of 0.5 kmol / m ³ potassium hydroxide ethanol solution used for titration (ml)
f: Factor of 0.5 kmol / m ³ potassium hydroxide ethanol solution S: Mass of aliphatic alcohol compound (g)
D: Acid value 28.05: Formula weight of potassium hydroxide 56.11 × 1/2

(Method for measuring weight average molecular weight of aliphatic alcohol compound)
An aliphatic alcohol compound is dissolved in o-dichlorobenzene to prepare a 0.15 g / L solution. 0.4 ml of the prepared solution is injected into a GPC apparatus, GPC-150C (manufactured by Waters Co., Ltd.) equipped with a column GMH-MT 30 cm2 (manufactured by Tosoh Corporation), and measured at a flow rate of 1.0 ml / min and a temperature of 135 ° C. The measured molecular weight in terms of polystyrene is further converted to polyethylene by a conversion formula derived from the Mark-Houwink viscosity formula to obtain the weight average molecular weight of the aliphatic alcohol compound.

(Fatty acid metal salt)
In the present invention, the addition ratio of the fatty acid metal salt is preferably in the range of 0.005 to 0.5 parts by mass, more preferably 0.01 to 0.2 parts by mass with respect to 100 parts by mass of the toner base particles. Within the scope of the part. When the addition ratio of the fatty acid metal salt is in the above range, the cleaning property can be further improved. That is, when the addition ratio of the fatty acid metal salt is 0.005 parts by mass or more, it is possible to avoid the fear that the effect is not manifested because the amount of the fatty acid metal salt is small, so that the cleaning property can be further improved. . Further, when the addition ratio of the fatty acid metal salt is 0.5 parts by mass or less, it is possible to avoid the possibility that the chargeability of the toner is lowered, and in turn, it is possible to avoid the possibility that the toner is likely to be scattered or fogged.

  The ratio of the addition ratio of the aliphatic alcohol compound and the addition ratio of the fatty acid metal salt varies depending on the particle size of the aliphatic alcohol compound and the fatty acid metal salt, but the mass ratio (addition ratio of the aliphatic alcohol compound / fatty acid metal salt The value of (addition ratio) is preferably in the range of 1 to 100. When the ratio of the addition ratio of the aliphatic alcohol compound and the addition ratio of the fatty acid metal salt is in the above range, the aliphatic alcohol compound can be reliably attached to the photoreceptor.

  Examples of the fatty acid metal salt include zinc stearate, calcium stearate, aluminum stearate, zinc laurate, and zinc myristate. These can be used alone or in combination of two or more.

  The number average particle diameter of the fatty acid metal salt is preferably in the range of 0.5 to 20 μm, more preferably in the range of 0.8 to 2 μm. When the number average particle diameter of the fatty acid metal salt is in the above range, sufficient cleaning properties can be obtained. That is, when the number average particle diameter of the fatty acid metal salt is 0.5 μm or more, it is possible to suppress an increase in adhesion to the toner particles. As a result, it is possible to prevent the toner from behaving together with the toner particles on the photosensitive member, thereby avoiding the possibility that the effect of improving the cleaning property cannot be exhibited. Moreover, when the number average particle diameter of the fatty acid metal salt is 20 μm or less, the possibility of image defects can be avoided.

(Measurement of number average particle size of aliphatic alcohol compounds and aliphatic metal salts)
The number average particle diameter of the aliphatic alcohol compound and the aliphatic metal salt is measured by an image analysis method.
Specifically, a photograph of the toner is taken at a magnification of 30,000 using a scanning electron microscope, the photograph image is captured by a scanner, and the image processing analysis apparatus “LUZEX AP (manufactured by Nireco)” The external additive present on the surface of the toner particles is binarized, the horizontal ferret diameter for any 100 particles is calculated, and the average value is taken as the number average particle diameter.

(Binder resin)
The binder resin constituting the toner particles is not particularly limited, and various known resins can be used. For example, styrene resin, acrylic resin, styrene-acrylic resin, polyester resin, silicone resin, olefin resin Amide resin or epoxy resin.
The binder resin preferably contains a styrene-acrylic resin from the viewpoint of toner particle size, shape controllability and chargeability.

Examples of the polymerizable monomer for obtaining a styrene-acrylic resin include styrene monomers such as styrene, methylstyrene, methoxystyrene, butylstyrene, phenylstyrene, chlorostyrene; methyl (meth) acrylate. , (Meth) acrylate ester monomers such as ethyl (meth) acrylate, butyl (meth) acrylate, ethylhexyl (meth) acrylate; carboxylic acid monomers such as acrylic acid, methacrylic acid and fumaric acid can do.
These can be used alone or in combination of two or more.

The glass transition point (Tg) of the binder resin is preferably in the range of 30 to 50 ° C, more preferably in the range of 30 to 45 ° C.
When the glass transition point of the binder resin is in the above range, both low-temperature fixability and heat-resistant storage stability can be obtained.

The glass transition point of the binder resin is measured using “Diamond DSC” (manufactured by PerkinElmer).
As a measurement procedure, 3.0 mg of a sample (binder resin) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were as follows: the measurement temperature was in the range of 0 ° C. to 200 ° C., the heating rate was 10 ° C./min, the cooling rate was 10 ° C./min, and Heat-cool-Heat temperature control was performed. Perform analysis based on the data in Heat, draw a baseline extension before the rise of the first endothermic peak, and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, The intersection point is shown as the glass transition point.

(Colored resin)
When the toner particles contain a colorant, generally known dyes and pigments can be used as the colorant.
As a colorant for obtaining a black toner, various known materials such as carbon black such as furnace black and channel black, magnetic materials such as magnetite and ferrite, dyes, and inorganic pigments containing nonmagnetic iron oxide are arbitrarily selected. Can be used.
As the colorant for obtaining a color toner, known ones such as dyes and organic pigments can be arbitrarily used. Specifically, examples of the organic pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, 238 269, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Blue 15; 3, 60, 76, and the like. Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 68, 11, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 69, 70, 93, 95 and the like.
The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color.
The content ratio of the colorant is preferably in the range of 1 to 10 parts by mass, more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

〔Release agent〕
When the toner particles contain a release agent, examples of the release agent include polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax, paraffin wax, and sazol wax. Long-chain hydrocarbon waxes such as dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehe Esters, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl maleate and other ester waxes, ethylenediamine base Niruamido, an amide-based waxes such as trimellitic acid tristearyl amide.

  The content ratio of the release agent is usually in the range of 1 to 30 parts by mass, more preferably in the range of 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the content ratio of the release agent is within the above range, sufficient fixing separation property can be obtained.

[Charge control agent]
When the charge control agent is contained in the toner particles, various known compounds can be used as the charge control agent.
The content ratio of the charge control agent is usually in the range of 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

(Average particle diameter of toner particles)
The average particle size of the toner particles according to the present invention is preferably in the range of 3 to 9 μm, and more preferably in the range of 3 to 8 μm, for example, on a volume basis median diameter. This particle size can be controlled by the concentration of the coagulant used, the amount of organic solvent added, the fusing time, and the composition of the polymer, for example, when the emulsion coagulation method described later is employed.
When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

The volume-based median diameter of the toner particles is measured and calculated using a measuring device in which “Multisizer 3” (manufactured by Beckman Coulter) is connected to a computer system equipped with data processing software “Software V3.51”. Is.
Specifically, 0.02 g of a sample (toner particles) was added to 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). And then let it disperse for 1 minute to prepare a toner particle dispersion, which is then placed in the sample stand “ISOTONII” (Beckman Coulter). Pipette into a beaker until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the measurement particle count number is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the range of 1 to 30 μm, which is the measurement range, into 256 parts, and from the larger volume integrated fraction A particle size of 50% is defined as a volume-based median diameter.

(Average circularity of toner particles)
The toner particles according to the present invention preferably have an average circularity in the range of 0.930 to 1.000, more preferably in the range of 0.950 to 0.995, from the viewpoint of improving transfer efficiency. is there.

In the present invention, the average circularity of toner particles is measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, the sample (toner particles) is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, photographing is performed at an appropriate density with an HPF detection number of 3000 to 10,000, the circularity is calculated for each toner particle according to the following formula (T), and the circularity of each toner particle is added. , By dividing by the total number of toner particles.
Formula (T): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

(Toner softening point)
The softening point of the toner is preferably in the range of 80 to 120 ° C., more preferably in the range of 90 to 110 ° C., from the viewpoint of obtaining low temperature fixability for the toner.

The softening point of the toner is measured by a flow tester shown below.
Specifically, first, in an environment of 20 ° C. and 50% RH, 1.1 g of a sample (toner) was placed in a petri dish and left flat for 12 hours or more, and then a molding machine “SSP-10A” (Shimadzu) Pressed with a force of 374.6 MPa (3820 kg / cm ² ) for 30 seconds to produce a cylindrical molded sample having a diameter of 1 cm. Then, the molded sample was subjected to an environment of 24 ° C. and 50% RH. In a cylindrical die (with a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min) by a flow tester “CFT-500D” (manufactured by Shimadzu Corporation). 1 mm diameter x 1 mm) from the end of preheating using a 1 cm diameter piston, offset method temperature measured at a setting of an offset value of 5 mm with the temperature rise method melting temperature measurement method T _offset is _defined as the softening point.

<Transfer process>
In this step, the toner image is transferred to the image support.
Transfer of the toner image to the image support is performed by peeling and charging the toner image to the image support.
As the transfer means, for example, a corona transfer device using corona discharge, a transfer belt, a transfer roller, or the like can be used.
In addition, in the transfer step, for example, an intermediate transfer member is used, and after a toner image is primarily transferred onto the intermediate transfer member, the toner image is secondarily transferred onto an image support. The toner image formed on the electrostatic latent image carrier can also be transferred directly to the image support.
The image support is not particularly limited, and is a plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper or coated paper, commercially available Japanese paper or postcard paper, and plastic film for OHP. And various kinds of cloth.

<Cleaning process>
In this step, the liquid developer that has not been used for image formation or remains untransferred is removed from the developer carrier such as a developing roller, a photoreceptor, and an intermediate transfer member. .
The cleaning method is not particularly limited, but it is preferable to use a blade that is provided with its tip abutting against the photoconductor and scratches the surface of the photoconductor.

[Electrophotographic image forming apparatus]
The electrophotographic image forming apparatus of the present invention includes a photosensitive member, a charging unit for charging the surface of the photosensitive member, an exposure unit for forming an electrostatic latent image on the surface of the photosensitive member, and developing the electrostatic latent image with toner. Developing means for forming a toner image, transfer means for transferring the toner image to a transfer material, fixing means for fixing the toner image transferred to the transfer material, and cleaning means for removing residual toner on the photoreceptor. The photoconductor of the present invention is used as the photoconductor. Further, it is preferable to use a blade that scratches the surface of the photoconductor, the tip of which is provided in contact with the photoconductor as the cleaning means.
As the electrophotographic image forming apparatus (hereinafter also referred to as “image forming apparatus”) used in the image forming method of the present invention, an apparatus in which the charging method is a charging roller method is used. Such a charging roller type image forming apparatus may have a configuration in which the charging roller is provided in contact with the photosensitive member or a configuration in which the charging roller is provided in close proximity.

FIG. 1 is an explanatory sectional view showing an example of the configuration of a charging roller type image forming apparatus used in the image forming method of the present invention.
FIG. 2 is a cross-sectional view for explaining an example of the configuration of the charging roller in the image forming apparatus shown in FIG.
This image forming apparatus applies a uniform potential to the surface of the photosensitive member 10 by a drum-like photosensitive member 10 which is an electrophotographic photosensitive member (electrostatic latent image carrier) and corona discharge having the same polarity as the toner. A charging unit composed of a charging roller 11; an exposure unit 12 that forms an electrostatic latent image by performing image exposure on the surface of the uniformly charged photoconductor 10 by using a polygon mirror or the like based on image data; and rotation. A developing sleeve 131, and a developing means 13 for conveying the toner held on the surface to the surface of the photoreceptor 10 to visualize the electrostatic latent image to form a toner image; Transfer means 14 for transferring to the transfer material P as necessary, separation means 16 for separating the transfer material P from the photoreceptor 10, fixing means 17 for fixing the toner image on the transfer material P, and on the photoreceptor 10 Residual toner And has a cleaning means having a cleaning blade 18 to be removed by.

[Electrophotographic photoconductor]
The electrophotographic photoreceptor used in the electrophotographic image forming method of the present invention has a structure in which at least an organic photosensitive layer and a protective layer are laminated in this order, and the protective layer contains particles containing a crosslinked resin and tin atoms (Sn). It is characterized by containing.
Moreover, it is preferable that the crosslinked resin according to the present invention is a crosslinked resin obtained by polymerizing a polymerizable compound having an acryloyl group or a methacryloyl group.
Moreover, it is preferable that the protective layer contains melamine resin particles.

  The layer structure of the photoreceptor is not particularly limited as long as the organic photosensitive layer and the protective layer are laminated in this order on the conductive support. Specifically, the following (1) and (2) The thing which has a layer structure is mentioned.

(1) A layer structure in which a charge generation layer, a charge transport layer, and a protective layer are laminated in this order as an intermediate layer and an organic photosensitive layer on a conductive support.
(2) A layer structure in which an intermediate layer, a layer containing a charge generation material and a charge transport material as an organic photosensitive layer, and a protective layer are laminated in this order on a conductive support.

  The electrophotographic photoreceptor according to the present invention is constituted by an organic compound exhibiting at least one of a charge generation function and a charge transport function, and is composed of a known organic charge generation material or organic charge transport material. All known photoreceptors such as a photoreceptor having an organic photosensitive layer and a photoreceptor having an organic photosensitive layer in which a charge generation function and a charge transport function are constituted by a polymer complex are included.

  The organic photosensitive layer can be prepared by various conventionally known production methods using conventionally known raw materials.

(Protective layer)
The protective layer according to the present invention includes at least a crosslinked resin (cured resin) and particles containing tin atoms (Sn). In the photoreceptor of the present invention, since the main component of the protective layer is a cross-linked resin, basically high film strength is obtained, and thus high durability is obtained, and tin contained in the cross-linked resin is also obtained. High potential characteristics can be obtained by particles containing atoms (Sn).
In addition, it is preferable that the layer thickness of a protective layer exists in the range of 0.2-10 micrometers, More preferably, it exists in the range of 0.5-5 micrometers.

(Crosslinked resin)
The crosslinked resin constituting the protective layer is obtained by polymerizing and curing a polymerizable compound. Specifically, the polymerizable compound is polymerized by irradiation with active rays such as ultraviolet rays and electron beams, It is obtained by curing.
In the present invention, the crosslinked resin is particularly preferably a crosslinked resin obtained by polymerizing a polymerizable compound having an acryloyl group or a methacryloyl group. Thereby, since the protective layer according to the present invention basically provides a high layer strength, durability can be improved.
In addition, a crosslinked resin is not limited to resin obtained by superposing | polymerizing the polymeric compound which has the said acryloyl group or methacryloyl group.

For example, examples of the polymerizable compound for synthesizing the crosslinked resin include styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, and N-vinyl pyrrolidone monomers. These polymerizable compounds can be used alone or in combination of two or more. As the polymerizable compound, a compound having an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—) as a polymerizable functional group can be cured with a small amount of light or in a short time. In particular, it is preferable to use a polymerizable compound having 2 to 6 polymerizable functional groups from the viewpoint that the crosslinking density of the resulting crosslinked resin is increased and the wear resistance can be improved. These polymerizable compounds are described in Japanese Patent Application Laid-Open No. 2011-175140, and some of the representative compounds are exemplified below.

Here, R represents an acryloyl group (CH ₂ ═CHCO—), and R ′ represents a methacryloyl group (CH ₂ ═CCH ₃ CO—).

(Particles containing tin atoms (Sn))
Examples of the particles containing tin atoms (Sn) according to the present invention include core-shell type composite particles in which the core is made of BaSO ₄ (barium sulfate) and the shell is made of SnO ₂ (tin oxide), and SnO ₂ particles. Composite particles consisting of BaSO ₄ and SnO ₂ Metropolitan Government is "Passtran -IV" manufactured by Mitsui Mining & Smelting Co., Ltd., SnO ₂ particles CIK Nanotech Co., Ltd. "NanoTek" is available as a commercial product.

  The number average primary particle size of the particles containing tin atoms (Sn) according to the present invention is preferably in the range of 1 to 300 nm, particularly in the range of 3 to 100 nm. Thereby, since the particle size is too small, it is possible to avoid the fear that the wear resistance improving performance is insufficient. On the contrary, it is possible to suppress the scattering of light at the time of image writing and the inhibition of the photocuring reaction at the time of forming the surface layer, which are caused by the particle size being too large, and thus avoid the possibility of adversely affecting the wear resistance. it can.

  Moreover, it is preferable that the particle | grains containing the tin atom (Sn) based on this invention are the particle | grains processed with the surface treating agent which has a polymerizable functional group from a viewpoint of the durable improvement of a photoreceptor. A representative example of the polymerizable functional group is a radical polymerizable functional group. Therefore, the surface treatment agent may be a compound having a radical polymerizable functional group and capable of covering the particle surface. A particularly preferred radical polymerizable functional group is a reactive acryloyl group or a methacryloyl group, and the portion bonded to the surface of the particle containing tin atoms (Sn) to cover the particle surface has a structure as a silane coupling agent. The surface treatment agent having a polymerizable functional group that can be preferably used in the present invention is a silane coupling agent having a reactive vinyl group, an acryloyl group, or a methacryloyl group.

  Hereinafter, a surface treatment agent having an acryloyl group or a methacryloyl group is shown as a specific example of the surface treatment agent.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC6H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C10H 2 1) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C6H 5) (OCH 3) 2

  Moreover, as a surface treating agent, you may use the silane compound which has a reactive organic group in which radical polymerization is possible other than what is shown to the said exemplary compound (S-1)-(S-36).

  You may use a surface treating agent individually by 1 type or in mixture of 2 or more types.

  The treatment amount of the surface treatment agent is preferably 0.1 to 200 parts by mass, more preferably 7 to 70 parts by mass with respect to 100 parts by mass of particles containing tin atoms (Sn).

  As a method for treating particles containing tin atoms (Sn) as a surface treatment agent, for example, a method of wet crushing a slurry (suspension of solid particles) containing particles containing tin atoms (Sn) and a surface treatment agent Is mentioned. By this method, re-aggregation of particles containing tin atoms (Sn) is prevented, and at the same time, surface treatment of particles containing tin atoms (Sn) proceeds. Thereafter, the solvent is removed to form powder.

  Examples of the surface treatment apparatus include a wet media dispersion type apparatus. In this wet media dispersion type apparatus, beads are filled as a medium in a container, and further, agitation disks attached perpendicular to the rotation axis are rotated at high speed to break up aggregated particles of particles containing tin atoms (Sn). It is an apparatus having a step of pulverizing / dispersing, and has a configuration in which particles containing tin atoms (Sn) can be sufficiently dispersed and subjected to surface treatment when surface treatment is performed on particles containing tin atoms (Sn). If it is, it will not be limited, For example, various styles, such as a vertical type, a horizontal type, a continuous type, and a batch type, are employable. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are finely pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding medium (media) such as balls and beads.

  As beads used in the wet media dispersion type apparatus, balls made of glass, alumina, zircon, zirconia, steel, flint stone, etc. can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicone carbide are particularly used. Is preferred.

  The protective layer according to the present invention may contain other components in addition to particles containing a crosslinked resin and tin atoms (Sn). For example, various antioxidants and various lubricant particles may be added. it can. For example, fluorine atom-containing resin particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

(Measurement of tin atom (Sn) content of protective layer)
The tin atom (Sn) content of the protective layer can be measured using a fluorescent X-ray analyzer “XRF-1700” (manufactured by Shimadzu Corporation). Specifically, first, a plurality of photoreceptors having a known content ratio of tin atoms (Sn) are prepared, the protective layer is scraped off, the sample 3g is pressed and pelletized, and the content ratio (mass content of tin atoms (Sn)) ppm) and the relationship (calibration curve) between the intensity of fluorescent X-rays (peak intensity) from tin atoms (Sn). Next, the protective layer whose content ratio of tin atoms (Sn) is to be measured is scraped, similarly pelletized, and the fluorescent X-ray intensity from the tin atoms (Sn) is measured. ) Content ".

(Melamine resin particles)
The number average primary particle size of the melamine resin particles according to the present invention is preferably in the range of 20 to 2000 nm, particularly in the range of 50 to 1000 nm. Within this range, since the diameter is too small, it is possible to avoid the fear that the wear resistance improving performance is insufficient. On the contrary, it is possible to suppress the scattering of light at the time of image writing and the inhibition of the photocuring reaction at the time of forming the surface layer, which are caused by the particle size being too large, and thus avoid the possibility of adversely affecting the wear resistance. it can.

  The melamine resin particles according to the present invention are preferably spherical. The melamine resin particles can be obtained as commercial products from Nippon Shokubai Co., Ltd. Eposter S, Eposter S6, and Eposter S12.

(Measurement method of the number average primary particle diameter of particles containing tin atoms (Sn) and melamine resin particles)
The number average primary particle size of particles containing tin atoms (Sn) and melamine resin particles is measured by an image analysis method.
Specifically, a magnified photograph of 100,000 times was taken with a scanning electron microscope (manufactured by JEOL Ltd.), and a photographic image (excluding aggregated particles) obtained by randomly capturing 300 particles with a scanner was automatically processed. Analyzing device “LUZEX (registered trademark) AP” (manufactured by Nireco Corporation) software version Ver. Calculate the number average primary particle size using 1.32.

(Universal hardness HU of photoreceptor surface)
The universal hardness HU of the surface of the photoreceptor is a hardness value obtained from a surface film physical property test using a Fisherscope H100V (trade name) manufactured by Fisher Instruments in accordance with ISO / FDIS14577. For the measurement, a square pyramid diamond indenter having a facing angle of 136 ° is used. The hardness value is obtained by stepping the measurement load F (unit: N) on the indenter and pushing it into the sample to be measured, and the indentation depth h (unit: mm) when the load is applied. It is a value calculated by the following formula (A). In the following formula (A), K = 1 / 26.43.
Formula (A): HU = K × F / h ² [N / mm ² ]

  Hereinafter, the configuration of the photoconductor other than the protective layer will be described in the case of the layer configuration (1).

[Conductive support]
The conductive support constituting the photoreceptor of the present invention may be any conductive support, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, A metal foil such as aluminum or copper laminated on a plastic film, a metal film deposited with aluminum, indium oxide, tin oxide or the like, a metal provided with a conductive layer by applying a conductive material alone or with a binder resin, Examples include plastic film and paper.

[Middle layer]
In the photoreceptor of the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive support and the organic photosensitive layer (hereinafter also referred to as “photosensitive layer”). In consideration of various failure prevention, it is preferable to provide an intermediate layer.

  Such an intermediate layer contains, for example, a binder resin (hereinafter also referred to as “binder resin for intermediate layer”) and, if necessary, conductive particles and metal oxide particles.

  Examples of the intermediate layer binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin. Among these, alcohol-soluble polyamide resins are preferable.

The intermediate layer can contain various conductive particles and metal oxide particles for the purpose of adjusting the resistance. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.
The number primary average particle diameter of such metal oxide particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  These metal oxide particles may be used alone or in combination of two or more. When two or more kinds are mixed, they may take the form of a solid solution or fusion.

  The content ratio of the conductive particles or the metal oxide particles is preferably in the range of 20 to 400 parts by mass, more preferably in the range of 50 to 350 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the intermediate layer is preferably in the range of 0.1 to 15 μm, more preferably in the range of 0.3 to 10 μm.

(Charge generation layer)
The charge generation layer in the photosensitive layer constituting the photoreceptor of the present invention contains a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”).

  Examples of charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone, diphthaloylpyrene, and the like. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generation materials may be used alone or in combination of two or more.

  As the binder resin for the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, chloride) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable.

  The content ratio of the charge generation material in the charge generation layer is preferably in the range of 1 to 600 parts by mass, more preferably in the range of 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin for charge generation layer. Is within.

  The layer thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin for charge generation layer, the content ratio, etc., but is preferably in the range of 0.01 to 5 μm, more preferably 0.05. Within the range of ~ 3 μm.

(Charge transport layer)
The charge transport layer in the photosensitive layer constituting the photoreceptor of the present invention contains a charge transport material and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”).

  Examples of the charge transport material for the charge transport layer include a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, and a butadiene compound as a material that transports charges (holes). Further, for example, the following compound A or compound B may be used as the charge transport material.

  A known resin can be used as the binder resin for the charge transport layer. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, styrene-methacrylic ester Examples of the resin include a copolymer resin, and a polycarbonate resin is preferable. Furthermore, BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, BPA-dimethyl BPA copolymer type polycarbonate resin and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The content ratio of the charge transport material in the charge transport layer is preferably in the range of 10 to 500 parts by weight, more preferably in the range of 20 to 250 parts by weight with respect to 100 parts by weight of the charge transport layer binder resin. Is within.

  The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics and the content ratio of the binder resin for the charge transport layer, but is preferably in the range of 5 to 40 μm, more preferably 10 to 30 μm. Within range.

  In the charge transport layer, an antioxidant, an electronic conductive agent, a stabilizer, silicone oil, or the like may be added. As the antioxidant, those disclosed in JP-A No. 2000-305291 and as the electronic conductive agent are disclosed in JP-A Nos. 50-137543 and 58-76483.

  According to the above photoreceptor, in the protective layer in which particles containing tin atoms (Sn) are contained in the cured resin, the ten-point average roughness RzJIS of the protective layer is within a specific range. High durability because the value of the formula (n × d) is within a specific range, that is, the number and size of the particles containing tin atoms (Sn) exposed to the protective layer are within the specific range. In addition, even when cleaning is performed by a cleaning means such as a blade, the frictional force or torque between the photosensitive member and the blade is reduced, and blade chatter and crease are generated, and the blade is worn. Can be suppressed.

[Method for producing photoreceptor]
As a manufacturing method of the photoreceptor of the present invention, for example, it can be manufactured through the following steps. Process (1): The process of forming an intermediate | middle layer by apply | coating the coating liquid for intermediate | middle layer formation to the outer peripheral surface of an electroconductive support body, and drying. Step (2): A step of forming a charge generation layer by applying a coating solution for forming a charge generation layer on the outer peripheral surface of an intermediate layer formed on a conductive support and drying it. Step (3): A step of forming a charge transport layer by applying a coating liquid for forming a charge transport layer to the outer peripheral surface of the charge generation layer formed on the intermediate layer and drying. Step (4): A protective layer-forming coating solution is applied to the outer peripheral surface of the charge transport layer formed on the charge generation layer to form a coating film, and this coating film is cured, thereby protecting the protective layer. Forming.

[Step (1): Formation of intermediate layer]
The intermediate layer is prepared by dissolving the binder resin for the intermediate layer in a solvent to prepare a coating solution (hereinafter also referred to as “intermediate layer coating solution”), and dispersing conductive particles and metal oxide particles as necessary. After that, the coating solution can be formed on the conductive support to a certain film thickness to form a coating film, and the coating film can be dried.

As a means for dispersing the conductive particles and metal oxide particles in the intermediate layer coating solution, an ultrasonic disperser, a ball mill, a sand mill, a homomixer or the like can be used, but is not limited thereto.
Examples of the coating method for the intermediate layer coating solution include known methods such as dip coating, spray coating, spinner coating, bead coating, blade coating, beam coating, slide hopper, and circular slide hopper. Can be mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The solvent used in the intermediate layer forming step is preferably a solvent in which conductive particles and metal oxide particles are well dispersed and the binder resin for the intermediate layer, particularly the polyamide resin, is dissolved. Specifically, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are excellent in solubility and coating performance of polyamide resin. preferable. In addition, examples of co-solvents that can be used in combination with the above-described solvent to improve storage stability and particle dispersibility and obtain a preferable effect include benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The concentration of the intermediate layer binder resin in the intermediate layer coating solution is appropriately selected according to the layer thickness and production rate of the intermediate layer.

[Step (2): Formation of Charge Generation Layer]
The charge generation layer is prepared by dispersing a charge generation material in a solution in which a binder resin for charge generation layer is dissolved in a solvent to prepare a coating liquid (hereinafter also referred to as “charge generation layer coating liquid”). It can be formed by coating the coating liquid on the intermediate layer to a certain film thickness to form a coating film and drying the coating film.

As a means for dispersing the charge generation material in the charge generation layer coating solution, for example, an ultrasonic disperser, a ball mill, a sand mill, a homomixer or the like can be used, but is not limited thereto.
Examples of the coating method for the charge generation layer coating solution include known methods such as dip coating, spray coating, spinner coating, bead coating, blade coating, beam coating, slide hopper, and circular slide hopper. Is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge generation layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, t-butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, Examples include, but are not limited to, 4-methoxy-4-methyl-2-pentanone, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine.

[Step (3): Formation of Charge Transport Layer]
The charge transport layer is prepared by preparing a coating liquid (hereinafter also referred to as “charge transport layer coating liquid”) in which a binder resin for a charge transport layer and a charge transport material are dissolved in a solvent, and applying the coating liquid on the charge generation layer. The film can be formed by applying the film to a certain thickness to form a coating film and drying the coating film.

Examples of the coating method for the charge transport layer coating solution include known methods such as dip coating, spray coating, spinner coating, bead coating, blade coating, beam coating, slide hopper, and circular slide hopper. Is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge transport layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, and 1,4. -Dioxane, 1,3-dioxolane, pyridine, diethylamine and the like are exemplified, but not limited thereto.

[Step (4): Formation of Protective Layer]
The protective layer is a coating liquid (hereinafter referred to as “protection”) by adding a polymerizable compound to form a cured resin, a polymerization initiator, particles containing tin atoms (Sn) and other components as necessary to a known solvent. The coating liquid for forming a layer ”) is prepared, and the coating liquid for forming the protective layer is applied to the outer peripheral surface of the charge transport layer formed in the step (3) to form a coating film. A protective layer can be formed by drying and irradiating active rays such as ultraviolet rays and electron beams to cause the polymerizable compound component in the coating film to undergo a polymerization reaction and cure.

  In the case where the protective layer is subjected to a surface treatment with a surface treatment agent having a polymerizable functional group, reaction between polymerizable compounds or particles containing tin atoms (Sn) in the course of coating, drying and curing Is formed as a cross-linked curable resin by a reaction between a polymerizable functional group of the surface treatment agent and a polymerizable compound.

As a means for dispersing the particles containing tin atoms (Sn) in the coating liquid for forming the protective layer, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but are not limited thereto. is not.
The ten-point average roughness RzJIS and the number of peak counts of the protective layer can also be controlled by the dispersion time of particles containing tin atoms (Sn).

  As the solvent used for forming the protective layer, any solvent can be used as long as it can dissolve or disperse particles containing a polymerizable compound and a tin atom (Sn). For example, methanol, ethanol, n-propyl alcohol, Isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3 Examples include, but are not limited to, dioxolane, pyridine and diethylamine.

  As a coating method of the coating liquid for forming the protective layer, for example, known methods such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, and a circular slide hopper method. A method is mentioned.

The coating liquid for forming the protective layer is preferably applied using a circular slide hopper coating apparatus.
Hereinafter, a method for applying the coating liquid for forming the protective layer using the circular slide hopper coating apparatus will be specifically described.

FIG. 3 is an explanatory cross-sectional view showing an example of the configuration of a circular slide hopper coating apparatus used in the method for producing a photoreceptor of the present invention. FIG. 4 is a perspective sectional view of the circular slide hopper coating apparatus shown in FIG.
As shown in FIGS. 3 and 4, the circular slide hopper coating apparatus includes a cylindrical base 251, an annular coating head 260 provided so as to surround the periphery thereof, and a storage tank 254 for storing the coating liquid L. It consists of.

  The base material 251 here is a base material to which the coating liquid for forming the protective layer is to be applied. For example, the base layer 251 in which the intermediate layer and the photosensitive layer are formed on the conductive support (the protective layer is formed). Not).

The coating head 260 has a narrow coating liquid distribution slit 262 having a coating liquid outlet 261 that opens to the base 251 side along the entire direction of the annular coating head 260 along the direction perpendicular to the longitudinal direction of the base 251. Is formed over. The coating liquid distribution slit 262 communicates with the annular coating liquid distribution chamber 263, and the coating liquid distribution chamber 263 is supplied with the coating liquid L in the storage tank 254 through the supply pipe 264 by the pumping pump 255. Is formed.
On the lower side of the coating liquid outlet 261 of the coating liquid distribution slit 262, there is formed a slide surface 265 that is continuously inclined downward and is formed with a dimension slightly larger than the outer dimension of the substrate 251. Furthermore, a lip portion (bead; liquid reservoir portion) 266 extending downward from the end of the slide surface 265 is formed.

  In such a circular slide hopper coating apparatus, when the coating liquid L is pushed out from the coating liquid distribution slit 262 and allowed to flow down along the slide surface 265 in the process of moving the base 251 in the direction of the arrow, the slide surface 265 ends. The resulting coating liquid L forms a bead between the end of the slide surface 265 and the outer peripheral surface of the substrate 251, and is then applied to the surface of the substrate 251 to form a coating film F. Is discharged from the discharge port 267.

  In such a coating method using a circular slide hopper coating device, the end of the slide surface and the substrate are arranged with a certain gap (within a range of about 2 μm to 2 mm), and the properties are not damaged. Even in the case of forming a plurality of different layers, it can be applied without damaging the already applied layer. Furthermore, when multiple layers with different properties and dissolved in the same solvent are formed, the time in the solvent is much shorter compared to the dip coating method. Can be applied without degrading the dispersibility of, for example, particles containing tin atoms (Sn).

  The coating film may be cured without being dried, but it is preferable to perform the curing treatment after natural drying or heat drying.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably in the range of room temperature to 180 ° C, particularly preferably in the range of 80 to 140 ° C. The drying time is preferably in the range of 1 to 200 minutes, particularly preferably in the range of 5 to 100 minutes.

  Examples of the method of reacting the polymerizable compound include a method of reacting by electron beam cleavage and a method of reacting with light and heat by adding a radical polymerization initiator. As the radical polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. Moreover, a photoinitiator and a thermal polymerization initiator can also be used together.

  As the radical polymerization initiator, a photopolymerization initiator is preferable, and among them, an alkylphenone compound or a phosphine oxide compound is preferable. In particular, a compound having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is preferable.

  Hereinafter, specific examples of acylphosphine oxide compounds as photopolymerization initiators are shown.

  The polymerization initiators may be used alone or in combination of two or more.

  The addition ratio of the polymerization initiator is preferably in the range of 0.1 to 20 parts by mass, more preferably in the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable compound.

  A cured resin is produced | generated by irradiating an active ray to a coating film as a hardening process, generating a radical, superposing | polymerizing, forming the cross-linking by a cross-linking reaction between molecules and in a molecule, and hardening. The actinic rays are more preferably ultraviolet rays or electron beams, and ultraviolet rays are particularly preferred because they are easy to use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used.
The irradiation conditions vary depending on individual lamps, irradiation of actinic rays is in the range of usually 5~500mJ / cm ^2, preferably in the range of 5 to 100 mJ / cm ^2.
The power of the lamp is preferably in the range of 0.1 to 5 kW, particularly preferably in the range of 0.5 to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably in the range of 100 to 300 kV. The absorbed dose is preferably in the range of 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary amount of active ray irradiation is preferably in the range of 0.1 second to 10 minutes, and more preferably in the range of 0.1 second to 5 minutes from the viewpoint of work efficiency.

  In the step of forming the protective layer, drying can be performed before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining these.

[Charging roller]
As shown in FIG. 2, the charging roller 11 is laminated on the surface of the core metal 11 a, and an elastic layer 11 b for reducing charging noise and imparting elasticity to obtain uniform adhesion to the photoreceptor 10. On the surface, a charging roller 11 is laminated with a resistance control layer 11c for obtaining highly uniform electrical resistance as a whole, and a surface layer 11d is laminated on the resistance control layer 11c. The structure is such that a charging nip portion is formed by being urged in the direction of the photoconductor 10 by a pressing spring 11 e and pressed against the surface of the photoconductor 10 with a predetermined pressing force. It is rotated following the rotation of.

  The cored bar 11a is, for example, plated with a metal such as iron, copper, stainless steel, aluminum and nickel, or the surface of these metals in a range not impairing conductivity in order to obtain rust prevention and scratch resistance. The outer diameter is 3 to 20 mm, for example.

  The elastic layer 11b is made of, for example, a material obtained by adding conductive fine particles made of carbon black, carbon graphite, or the like, or conductive salt fine particles made of an alkali metal salt, ammonium salt, or the like to an elastic material such as rubber. Specific examples of the elastic material include natural rubber, ethylene propylene diene methylene rubber (EPDM), styrene-butadiene rubber (SBR), silicone rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), and butadiene rubber (BR). And synthetic rubbers such as nitrile-butadiene rubber (NBR) and chloroprene rubber (CR), polyamide resins, polyurethane resins, silicone resins and fluororesins, and foamed sponges. The magnitude of elasticity can be adjusted by adding process oil, plasticizer and the like to the elastic material.

The elastic layer 11b preferably has a volume resistivity in the range of 1 × 10 ¹ to 1 × 10 ¹⁰ Ω · cm. Moreover, it is preferable that the layer thickness is 500-5000 micrometers, More preferably, it is 500-3000 micrometers.
The volume resistivity of the elastic layer 11b is a value measured according to JIS K 6911.

  The resistance control layer 11c is provided for the purpose of having a uniform electric resistance as a whole for the charging roller 11, but may be omitted. The resistance control layer 11c can be provided by coating a material having moderate conductivity or covering a tube having moderate conductivity.

  Specific materials constituting the resistance control layer 11c include basic materials such as resins such as polyamide resin, polyurethane resin, fluorine resin, and silicone resin; rubbers such as epichlorohydrin rubber, urethane rubber, chloroprene rubber, and acrylonitrile rubber. Conductive fine particles made of carbon black, carbon graphite, etc .; conductive metal oxide fine particles made of conductive titanium oxide, conductive zinc oxide, conductive tin oxide, etc .; conductive properties made of alkali metal salt, ammonium salt, etc. Examples include those to which a conductive agent such as salt fine particles is added.

The volume resistivity of the resistance control layer 11c is preferably in the range of 1 × 10 ⁻² to 1 × 10 ¹⁴ Ω · cm, more preferably 1 × 10 ¹ to 1 × 10 ¹⁰ Ω · cm. Moreover, it is preferable that the layer thickness is 0.5-100 micrometers, More preferably, it is 1-50 micrometers, More preferably, it is 1-20 micrometers.
The volume resistivity of the resistance control layer 11c is a value measured according to JIS K 6911.

  The surface layer 11d is used for the purpose of preventing bleeding out of the surface of the obtained charging roller such as a plasticizer in the elastic layer 11b, the purpose of obtaining the slipperiness and smoothness of the surface of the charging roller, or a pin on the photoreceptor 10. Even if there is a defect such as a hole, it is provided for the purpose of preventing the occurrence of leakage, etc., and it is applied with a material having an appropriate conductivity, or a tube having an appropriate conductivity is coated. Is provided.

  When the surface layer 11d is provided by material coating, specific materials include polyamide resin, polyurethane resin, acrylic resin, fluororesin and silicone resin, epichlorohydrin rubber, urethane rubber, chloroprene rubber, and acrylonitrile rubber. Conductive agents such as conductive fine particles made of carbon black, carbon graphite, etc .; conductive metal oxide fine particles made of conductive titanium oxide, conductive zinc oxide, conductive tin oxide, etc. were added to basic materials such as Things. Examples of the coating method include a dip coating method, a roll coating method, and a spray coating method.

  Further, when the surface layer 11d is provided by covering the tube, as a specific tube, nylon 12, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), polyvinylidene fluoride, tetrafluoroethylene-6 Fluorinated propylene copolymer resin (FEP): Polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, and other thermoplastic elastomers added with the above conductive agents are molded into tubes The thing which was done is mentioned. This tube may be heat-shrinkable or non-heat-shrinkable.

The surface layer 11d preferably has a volume resistivity in the range of 1 × 10 ¹ to 1 × 10 ⁸ Ω · cm, more preferably 1 × 10 ¹ to 1 × 10 ⁵ Ω · cm. Moreover, it is preferable that the layer thickness is 0.5-100 micrometers, More preferably, it is 1-50 micrometers, More preferably, it is 1-20 micrometers.
The volume resistivity of the surface layer 11d is a value measured according to JIS K 6911.

  The surface layer 11d preferably has a surface roughness Rz of 1 to 30 μm, more preferably 2 to 20 μm, and still more preferably 5 to 10 μm.

  In the charging roller 11 as described above, a charging bias voltage is applied from the power source S1 to the metal core 11a of the charging roller 11, whereby the surface of the photoconductor 10 is charged to a predetermined potential with a predetermined polarity. Here, the charging bias voltage can be, for example, an oscillating voltage in which an AC voltage (Vac) is superimposed on a DC voltage (Vdc).

  An example of the charging conditions by the charging roller shown in FIG. 2 is a sine wave having a DC voltage (Vdc) forming a charging bias voltage of −500 V, an AC voltage (Vac) of 1000 Hz, and a peak-to-peak voltage of 1300 V. By applying this charging bias voltage, the surface of the photoreceptor 10 is uniformly charged to -500V.

  The charging roller 11 has a length based on the length in the longitudinal direction of the photoconductor 10, and the length in the longitudinal direction can be set to 320 mm, for example.

[Cleaning blade]
As the cleaning blade 18 used in the image forming method of the present invention, one made of a rubber material which is an elastic body is preferably used. Examples of rubber materials include urethane rubber, silicone rubber, fluorine rubber, chloropyrene rubber, and butadiene rubber. Among these, urethane rubber is particularly excellent in wear characteristics compared to other rubbers. It is preferable to use urethane rubber.

  The shape and material of the cleaning blade 18 may be appropriately determined according to various conditions such as toner characteristics, photoconductor characteristics, intermediate transfer body, secondary transfer body, and contact angle and contact pressure of the cleaning blade 18. it can.

  In this image forming apparatus, the toner image formed on the photoconductor 10 is transferred by the transfer unit 14 onto the transfer material P conveyed at the same timing, and is separated from the photoconductor 10 by the separation unit 16 and fixed. By fixing in the means 17, a visible image is formed.

  The image forming apparatus used in the image forming method of the present invention is not limited to the one having the above configuration, and a color image having a configuration in which image forming units related to a plurality of photoconductors are provided along the intermediate transfer body. It may be a forming device.

  According to the electrophotographic image forming apparatus as described above, since the photoconductor of the present invention is provided, a high-quality image can be formed over a long period of time.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<Toner Preparation Example 1>
(1) Formation of toner base particles (colored particles) (1-1) Production process of resin fine particles [1] for core portion A multilayer structure is obtained through first-stage polymerization, second-stage polymerization, and third-stage polymerization shown below. The core resin fine particles [1] were prepared.

(A) First stage polymerization (resin fine particles [A1])
A surfactant solution prepared by dissolving 4 parts by mass of sodium polyoxyethylene-2-dodecyl ether sulfate in 3040 parts by mass of ion-exchanged water in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction apparatus. The internal temperature was raised to 80 ° C. while stirring and stirring at a stirring speed of 230 rpm under a nitrogen stream. To this surfactant solution, a polymerization initiator solution in which 10 parts by mass of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 parts by mass of ion-exchanged water was added to a temperature of 75 ° C., and then 532 masses of styrene. A monomer mixture consisting of 1 part by weight, 200 parts by weight of n-butyl acrylate, 68 parts by weight of methacrylic acid, and 16.4 parts by weight of n-octyl mercaptan was dropped over 1 hour, and this system was kept at 75 ° C. for 2 hours. Polymerization (first stage polymerization) was carried out by heating and stirring to produce resin fine particles [A1]. The weight average molecular weight (Mw) of the resin fine particles [A1] produced by the first stage polymerization was 16,500.

The weight average molecular weight (Mw) was measured using “HLC-8220” (manufactured by Tosoh Corporation) and the column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation) while maintaining the column temperature at 40 ° C. and tetrahydrofuran as a carrier solvent. (THF) was allowed to flow at a flow rate of 0.2 ml / min, and the measurement sample was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which treatment was performed for 5 minutes using an ultrasonic disperser at room temperature. A sample solution is obtained by processing with a 2 μm membrane filter, and 10 μl of this sample solution is injected into the apparatus together with the above carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight of the measurement sample Use a calibration curve whose distribution was measured using monodisperse polystyrene standard particles. And calculate. As a standard polystyrene sample for calibration curve measurement, the molecular weights manufactured by Pressure Chemical are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 .1 × 10 ⁵ , 3.9 × 10 ⁶ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and at least about 10 standard polystyrene samples were measured, and a calibration curve It was created. A refractive index detector was used as the detector.

(B) Second stage polymerization (resin fine particles [A2]: formation of intermediate layer)
In a flask equipped with a stirrer, a monomer mixture comprising 101.1 parts by mass of styrene, 62.2 parts by mass of n-butyl acrylate, 12.3 parts by mass of methacrylic acid, and 1.75 parts by mass of n-octyl mercaptan As a release agent, 93.8 parts by mass of paraffin wax “HNP-57” (manufactured by Nippon Seiwa Co., Ltd.) was added and heated to 90 ° C. for dissolution.

  On the other hand, a surfactant solution in which 3 parts by mass of sodium polyoxyethylene-2-dodecyl ether sulfate was dissolved in 1560 parts by mass of ion-exchanged water was heated to 98 ° C., and the resin fine particles [A1 ] 32.8 parts by mass (in terms of solid content) was added, and the monomer solution containing the paraffin wax was mixed and dispersed for 8 hours using a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. And a dispersion containing emulsified particles having a dispersed particle diameter of 340 nm was prepared. Next, a polymerization initiator solution in which 6 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added to this emulsified particle dispersion, and the system was polymerized by heating and stirring at 98 ° C. for 12 hours. (Second-stage polymerization) was performed to produce resin fine particles [A2]. The resin fine particles [A2] prepared by the second stage polymerization had a weight average molecular weight (Mw) of 23,000.

(C) Third-stage polymerization (core resin fine particles [1]: formation of outer layer)
A polymerization initiator solution in which 5.45 parts by mass of potassium persulfate was dissolved in 220 parts by mass of ion-exchanged water was added to the resin fine particles [A2], and 293.8 parts by mass of styrene under a temperature condition of 80 ° C. A monomer mixed solution consisting of 154.1 parts by mass of n-butyl acrylate and 7.08 parts by mass of n-octyl mercaptan was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain resin particles [1] for the core part. In addition, the weight average molecular weight (Mw) of the resin fine particles for core part [1] was 26800. The volume average particle diameter of the resin fine particles [1] for core portion was 125 nm. Furthermore, the glass transition point (Tg) of the resin fine particles [1] for the core portion was 28.1 ° C.

(1-2) Production process of resin fine particle [1] for shell layer In the first stage polymerization of the resin fine particle [1] for the core part, 548 parts by mass of styrene, 156 parts by mass of 2-ethylhexyl acrylate, methacrylic acid In the same manner except that a monomer mixed solution in which n-octyl mercaptan was changed to 16.5 parts by mass was subjected to a polymerization reaction and post-reaction treatment, and resin particles for shell layer [1] Was made. The glass transition point (Tg) of the resin fine particles for shell layer [1] was 53.0 ° C.

(1-3) Preparation of Colorant Fine Particle Dispersion 90 parts by mass of sodium dodecyl sulfate was added to 1600 parts by mass of ion-exchanged water, and while stirring this solution, 420 parts by mass of carbon black “Regal 330R” (manufactured by Cabot) Was then gradually added, followed by a dispersion treatment using a stirrer “CLEARMIX” (manufactured by M Technique Co., Ltd.) to prepare a colorant fine particle dispersion [1] in which colorant fine particles were dispersed.
The particle diameter of the colorant fine particles in this colorant fine particle dispersion [1] was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and found to be 110 nm.

(1-4) Preparation of toner base particles [1] (a) Formation of core part [1] 420 parts by mass of resin fine particles for core [1] (in terms of solid content), 900 parts by mass of ion-exchanged water, and coloring 100 parts by mass of the agent fine particle dispersion [1] was placed in a reaction vessel equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device and stirred. After adjusting the temperature in the reaction vessel to 30 ° C., 5 mol / liter sodium hydroxide aqueous solution was added to this solution to adjust the pH within the range of 8-11.
Next, an aqueous solution in which 60 parts by mass of magnesium chloride hexahydrate was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the heating was started, and the system was heated to 80 ° C. (core formation temperature) over 80 minutes. In this state, the particle diameter of the particles was measured with “Coulter Multisizer 3” (manufactured by Coulter Inc.), and when the volume-based median diameter (D ₅₀ ) of the particles became 5.8 μm, sodium chloride 40.2 An aqueous solution in which parts by mass are dissolved in 1000 parts by mass of ion-exchanged water is added to stop the growth of the particle size, and further, as an aging treatment, the mixture is heated and stirred at a liquid temperature of 80 ° C. (core part aging temperature) for 1 hour. Wearing was continued to form the core [1]. The circularity of the core [1] was 0.930 as measured by “FPIA2100” (manufactured by Sysmex Corporation). In addition, using a field emission scanning electron microscope JSM-7401F (manufactured by JEOL Ltd.), the core part [1] was observed at a magnification of 10,000 by scanning transmission electron microscopy, and the colorant was dissolved in the binder resin. It was confirmed that no colorant-dispersed fine particles remained.

(B) Formation of Shell Layer Next, 46.8 parts by mass of resin fine particles for shell layer [1] (in terms of solid content) are added at 65 ° C., and further 2 parts by mass of magnesium chloride hexahydrate is added to ion-exchanged water 60 An aqueous solution dissolved in parts by mass was added over 10 minutes, and then the temperature was raised to 80 ° C. (shell formation temperature), and stirring was continued for 1 hour. Resin fine particles for the shell layer were formed on the surface of the core part [1]. After fusing the particles of [1], aging treatment was performed at 80 ° C. (shell aging temperature) to a predetermined circularity to form a shell layer. Here, an aqueous solution in which 40.2 parts by mass of sodium chloride was dissolved in 1000 parts by mass of ion-exchanged water was added, and the mixture was cooled to 30 ° C. at 8 ° C./min. By repeatedly washing with exchanged water and then drying with hot air at 40 ° C., the volume-based median diameter (D ₅₀ ) having a shell layer on the surface of the core part is 5.9 μm, and the glass transition point (Tg) is Toner base particles [1] at 31 ° C. were obtained.

(2) Addition of external additive To 100 parts by mass of the dried toner base particles [1], 0.5 part by mass of an aliphatic alcohol compound (average molecular weight 1000, hydroxy value 33, particle size 5 μm), and negative chargeability 1 part by mass of silica “RX-200 (manufactured by Nippon Aerosil Co., Ltd.)” and 1 part by mass of negatively charged silica “NX90 (manufactured by Nippon Aerosil Co., Ltd.)” were added, and the peripheral speed of the rotating blades using a Henschel mixer (manufactured by Nippon Coke) Was mixed for 20 minutes at a processing temperature of 32 ° C., and then coarse particles were removed using a sieve having an opening of 45 μm to prepare toner [1].

<Photoconductor Preparation Example 1>
(Preparation of conductive support)
The surface of a cylindrical aluminum support having a diameter of 60 mm was cut to produce a conductive support having a fine and rough surface.

(Formation of intermediate layer)
A dispersion having the following composition was diluted twice with the same mixed solvent, allowed to stand overnight, and then filtered using a rigid mesh 5 μm filter manufactured by Nihon Pall, to prepare an intermediate layer coating solution.

Polyamide resin (CM8000: manufactured by Toray Industries, Inc.) 1 part by mass Titanium oxide (SMT500SAS: manufactured by Teika) 3 parts by mass Methanol 10 parts by mass Using a sand mill as a disperser, dispersion was carried out for 10 hours in a batch system.

  The intermediate layer coating solution was applied on the conductive support by a dip coating method so as to have a dry film thickness of 2 μm, and dried to form an intermediate layer.

(Formation of charge generation layer)
Charge generation material: The following pigment [CG-1]: 20 parts by mass Polyvinyl butyral resin (# 6000-C: manufactured by Denki Kagaku Kogyo) 10 parts by mass t-butyl acetate 700 parts by mass 4-methoxy-4-methyl-2- 300 parts by mass of pentanone was mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This charge generation layer coating solution was applied on the intermediate layer by a dip coating method and dried to form a charge generation layer having a dry film thickness of 0.3 μm.

[Synthesis of Pigment (CG-1)]
(1) Synthesis of amorphous titanyl phthalocyanine 29.2 parts by mass of 1,3-diiminoisoindoline is dispersed in 200 parts by mass of orthodichlorobenzene, and 20.4 parts by mass of titanium tetra-n-butoxide is added under a nitrogen atmosphere. For 5 hours in the range of 150-160 ° C. After allowing to cool, the precipitated crystals are filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to give 26.2 parts by mass (yield 91%) of crude titanyl phthalocyanine. Got.
Next, this crude titanyl phthalocyanine was added to 250 parts by mass of concentrated sulfuric acid, dissolved by stirring at 5 ° C. or less for 1 hour, poured into 5000 parts by mass of water at 20 ° C., and the precipitated crystals were filtered and sufficiently By washing with water, 225 parts by mass of a wet paste product was obtained, frozen in a freezer, thawed, filtered, and dried to obtain 24.8 parts by mass of amorphous titanyl phthalocyanine (yield 86%). .

(2) Synthesis of (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine [CG-1] 10.0 parts by mass of the above-mentioned amorphous titanyl phthalocyanine and (2R, 3R) -2,3-butane 0.94 parts by mass of a diol (equivalent ratio to amorphous titanyl phthalocyanine = 0.6) was mixed in 200 parts by mass of orthodichlorobenzene, and heated and stirred within a range of 60 to 70 ° C. for 6.0 hours. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The filtered crystals were washed with methanol, whereby the pigment ((2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine was obtained. Pigment to contain) [CG-1] 10.3 g was obtained.
When the X-ray diffraction spectrum of [CG-1] was measured, clear peaks were observed at 8.3 °, 24.7 °, 25.1 °, and 26.5 °. The measured mass spectrum, show a peak in the 576 and 648, also was measured for IR spectrum, O-Ti-O in the vicinity of 630 cm ^-1 with absorption of Ti = O appears in the vicinity of 970 cm ^-1 Both absorptions appeared. Further, when thermal analysis (TG) was performed, there was a mass loss of about 7% within the range of 390 to 410 ° C. From the above, [CG-1] is a mixed crystal of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol 1: 1 adduct and non-added (not not allowed) titanyl phthalocyanine. Estimated.
It was 31.2 m < ² > / g when the BET specific surface area of this [CG-1] was measured.

  The X-ray diffraction spectrum was measured using a sample obtained by coating [CG-1] on a transparent glass plate and drying it. The BET specific surface area was measured using a flow type specific surface area automatic measuring device “Micrometrics Flow Soap Type” (manufactured by Shimadzu Corporation).

(Formation of charge transport layer)
Charge transport material (compound A) 225 parts by weight Binder: Polycarbonate Z (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by weight Antioxidant (Irganox 1010: manufactured by BASF Japan) 6 parts by weight THF (tetrahydrofuran) 1600 parts by weight Toluene 400 Part by mass Silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass was mixed and dissolved to prepare a charge transport layer coating solution.
This coating solution was applied onto the charge generation layer using a circular slide hopper coating machine to form a charge transport layer having a dry film thickness of 20 μm.

(Formation of protective layer)
First, the surface treatment of particles containing tin atoms (Sn) was performed with a surface treatment agent having a polymerizable functional group as follows.
Particles containing tin atoms (Sn): SnO ₂ (manufactured by CIK Nanotech, number average primary particle diameter 20 nm, volume resistivity: 1.05 × 10 ⁵ (Ω · cm)) 100 parts by mass, surface treatment agent: example compound _{(S-15: CH 2 =} C (CH 3) COO (CH 2) 3 Si (OCH 3) 3) 30 parts by mass, solvent: a mixed solvent 300 of toluene / isopropyl alcohol = 1/1 (weight ratio) A mass part of the mixed solution is put into a sand mill together with zirconia beads, stirred at a rotational speed of 1500 rpm at about 40 ° C., and further, the treated mixture is taken out, put into a Henschel mixer and stirred at a rotational speed of 1500 rpm for 15 minutes, and then 120 by drying for 3 hours at ° C., subjected to surface treatment with a compound having a polymerizable functional group to SnO _2, surface-treated Sn ₂ was obtained.
By this surface treatment, the particle surface of SnO ₂ was covered with the exemplary compound (S-15).

Surface-treated SnO ₂ 80 parts by mass Polymerizable compound (Exemplified Compound M1) 100 parts by mass Charge transport material (Compound B) 20 parts by mass Polymerization initiator (Irgacure 819: manufactured by BASF Japan Ltd.) 10 parts by mass 2-butanol A coating solution composition comprising 320 parts by mass of tetrahydrofuran and 80 parts by mass of the mixture was mixed and stirred to sufficiently dissolve or disperse it, thereby preparing a coating solution for forming a protective layer. This protective layer-forming coating solution is applied onto the charge transport layer using a circular slide hopper applicator, and after application, it is irradiated with ultraviolet light for 1 minute using a metal halide lamp to protect the dry film thickness of 3.0 μm. A layer was formed, thereby producing a photoreceptor [1].
When the universal hardness HU of the surface of the obtained photoreceptor [1] was measured by the method described above, it was 240 N / mm ² .

<Photoconductor Preparation Example 2>
It was produced in the same manner as the photoreceptor [1] except that the particles containing tin atoms (Sn) were changed to the following.
Particles containing tin atoms (Sn): Core-BaSO ₄ , core-shell particles of shell-SnO ₂ (“Pastran” manufactured by Mitsui Metal Mining Co., Ltd., number average primary particle diameter 100 nm, volume resistivity: 3.3 × 10 ⁵ (Ω · cm)) 100 parts by mass When the universal hardness HU of the surface of the obtained photoreceptor [2] was measured by the method described above, it was 280 N / mm ² .

<Photoconductor Preparation Example 3>
The following melamine resin particles were prepared in the same manner as the photoreceptor [2] except that the protective layer forming coating solution for the photoreceptor [2] was added.
Melamine resin particles (Nippon Shokubai Co., Ltd. “Eposter S”, number average primary particle size 200 nm): 40 parts by mass When the universal hardness HU of the surface of the obtained photoreceptor [2] was measured by the method described above, 320 N / mm ² .

<Photoconductor Preparation Example 4> (Comparative Example)
It was produced in the same manner as the photoreceptor [1], except that particles containing tin atoms (Sn) were not added to the protective layer-forming coating solution.
When the universal hardness HU of the surface of the obtained photoreceptor [4] was measured by the method described above, it was 150 N / mm ² .

<Toner Preparation Examples 2 to 16>
Toners [2] to [16] were prepared in the same manner as in the toner preparation example 1 except that (2) the external additive was added in accordance with the formulation shown in Table 1 in the external additive addition step. did.

[Manufacture of developer]
For each of the toners [1] to [16], a developer carrier [1] is mixed with a ferrite carrier having a volume average particle diameter of 35 μm coated with a silicone resin so that the toner concentration becomes 7.5% by mass. To [16] were prepared.

<Examples 1-15, Comparative Examples 1-6>

<Evaluation method>
The charging means of the digital color MFP “bizhub C360” (manufactured by Konica Minolta Co., Ltd.) is modified to a charging roller type as shown in FIG. 1, and the above photoconductors [1] to [4] are used as photoconductors. A modified machine (electrophotographic image forming device) was prepared. Next, with the combinations shown in Table 1, developers [1] to [16] were loaded into a modified machine equipped with photoreceptors [1] to [4]. Image formation was performed with an electrophotographic image forming apparatus loaded with a developer, and photoreceptor wear, image unevenness, and cleaning properties were evaluated.
In each modified machine, a charging roller made of nylon resin and having a diameter of 1.0 cmφ was used.
The cleaning blade is installed so that the angle formed with the photoconductor is 7.5 ° and the contact pressure is variable within the range of 29.4 to 68.6 kPa (3.0 to 7.0 gf / mm ² ). did.
The evaluation results are shown in Table 2 below.

(Photoconductor wear)
Evaluation of photoconductor wear was performed before and after forming 50,000 images at 5% image density under low temperature and low humidity (10 ° C., 15 RH%) using A4 fine paper (64 g / m ² ). Was observed and measured using a laser microscope VK9500 (magnification 20 times, observation field of view 5.20 mm × 3.80 mm), and the difference between the average values was evaluated as Δ film thickness. The results are shown in Table 2. In the present invention, if the Δ film thickness is less than 10 μm (if “」 ”or“ ◯ ”), it is determined that there is no practical problem.
-Evaluation criteria-
A: Δ film thickness <1 μm
○: 1μm ≦ Δ film thickness <3μm
Δ: 3 μm ≦ Δ film thickness <5 μm
×: 5 μm ≦ Δ film thickness

(Image unevenness)
Using the above-described electrophotographic image forming apparatus in which developers [1] to [16] are sequentially loaded, an image having a pixel rate of 40% in a high temperature and high humidity environment (temperature 30 ° C., humidity 85% RH) 1000 continuous prints on high-quality paper (64 g / m ² ), the presence or absence of image unevenness in each print was confirmed visually, and the ratio of the number x of prints where image unevenness occurred (x / 1000) × 100 Was used as an image unevenness occurrence rate, and the occurrence of image unevenness was evaluated. The results are shown in Table 2. In the present invention, if the image unevenness is less than 0.5% (if “◎” or “◯”), it is determined that there is no practical problem.
-Evaluation criteria-
A: Image unevenness occurrence rate <0.2%
○: 0.2% ≦ image unevenness occurrence rate <0.5%
Δ: 0.5% ≦ image unevenness occurrence rate <1.0%
×: 1.0% ≦ image unevenness occurrence rate

(Cleanability)
Using the above-described electrophotographic image forming apparatus in which developers [1] to [16] are sequentially loaded, an image having a pixel rate of 5% in a low-temperature and low-humidity environment (temperature 10 ° C., humidity 10% RH) After 100,000 sheets were printed on paper (64 g / m ² ), a solid test image (grit voltage 450 V, development potential: 350 V) was output, and the solid image and the photoreceptor were visually observed and evaluated. The cleaning blade was installed so that the angle formed with the photoconductor was 7.5 ° and the contact pressure was variable within the range of 29.4 to 68.6 kPa (3.0 to 7.0 gf / mm ² ).
The results are shown in Table 2. In the present invention, if the contact pressure of the cleaning blade is 49.0 kPa (5.0 gf / mm ² ) or less and there is no toner slip on the test image (if it is “「 ”or“ ◯ ”), there is no practical problem. It is judged.
-Evaluation criteria-
A: The contact pressure is 29.4 kPa (3.0 gf / mm ² ), and no toner slips out on the test image.
A: The contact pressure is 49.0 kPa (5.0 gf / mm ² ), and no toner slips out on the test image.
Δ: The contact pressure is 68.6 kPa (7.0 gf / mm ² ), and no toner slip is observed on the test image.
×: The contact pressure is 68.6 kPa (7.0 gf / mm ² ), and toner slippage is visually recognized on the test image.

  From the results shown in Table 2, it is recognized that Examples 1 to 15 have improved wear resistance, improved image unevenness, and suppressed toner slippage compared to Comparative Examples 1 to 6. It was.

DESCRIPTION OF SYMBOLS 10 Photoconductor 11 Charging roller 11a Metal core 11b Elastic layer 11c Resistance control layer 11d Surface layer 11e Pressure spring 12 Exposure means 13 Development means 131 Development sleeve 14 Transfer means 16 Separation means 17 Fixing means 18 Cleaning blade 251 Base material 254 Storage tank 255 Pressure feed pump 260 Application head 261 Application liquid outlet 262 Application liquid distribution slit 263 Application liquid distribution chamber 264 Supply pipe 265 Slide surface 266 Lip portion 267 Discharge port P Transfer material

Claims (7)

An electrophotographic image forming method comprising a charging step, an electrostatic latent image forming step, a developing step, a transfer step, and a cleaning step,
The electrophotographic photosensitive member used in the electrophotographic image forming method has a configuration in which at least an organic photosensitive layer and a protective layer are laminated in this order,
The protective layer contains a crosslinked resin and particles containing tin atoms (Sn),
The toner used in the electrophotographic image forming method is obtained by adding an external additive to toner base particles containing a binder resin and a colorant,
The external additive contains an aliphatic alcohol compound having a weight average molecular weight in the range of 300 to 1500 and a hydroxy value in the range of 20 to 170 mgKOH / g. .   2. The electrophotographic image forming method according to claim 1, wherein the cross-linked resin of the protective layer is a cross-linked resin obtained by polymerizing a polymerizable compound having an acryloyl group or a methacryloyl group. Particles containing the tin atoms (Sn) is an electrophotographic image according to claim 1 or claim 2 characterized in that it is a composite particle comprising at least consisting of SnO ₂ particles or at least SnO ₂ and BaSO ₄ Metropolitan Forming method.   4. The electron according to claim 1, wherein the tin atom (Sn) -containing particle is a particle treated with a surface treatment agent having a polymerizable functional group. 5. Photographic image forming method.   The electrophotographic image forming method according to any one of claims 1 to 4, wherein the protective layer contains melamine resin particles.   The electrophotographic image forming method according to any one of claims 1 to 5, wherein the external additive contains a fatty acid metal salt. An electrophotographic image forming apparatus using the electrophotographic image forming method according to any one of claims 1 to 6,
At least a charging means, an exposure means, a developing means and a transfer means,
The electrophotographic photoreceptor used in the electrophotographic image forming apparatus has a configuration in which at least an organic photosensitive layer and a protective layer are laminated in this order,
The protective layer contains a crosslinked resin and particles containing tin atoms (Sn),
The toner used in the electrophotographic image forming apparatus is obtained by adding an external additive to toner base particles containing a binder resin and a colorant,
The external additive contains an aliphatic alcohol compound having a weight average molecular weight in the range of 300 to 1500 and a hydroxy value in the range of 20 to 170 mgKOH / g. .

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