JP2008122869A - Image forming apparatus, process cartridge, and image forming method - Google Patents

Abstract

Even under charging, particularly under AC charging, the life of the entire member around the image carrier, such as suppression of wear of the image carrier, maintenance of cleaning properties, and suppression of contamination of the charging member, can be realized, and over a long period of time. An image forming apparatus, a process cartridge, and an image forming method having a simple configuration capable of outputting a good image.
An image carrier 20Y, a charging unit 90Y for charging the image carrier 20Y, a lubricant application unit 40Y for applying a lubricant 42Y to the image carrier 20Y, and lubrication in a moving direction B1 of the image carrier 20Y. And a lubricant removing means 50Y for removing the powdery lubricant 42Y on the image carrier 20Y located downstream from the agent applying means 40Y and upstream from the charging means 90Y.
[Selection] Figure 2

Description

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

  In an image forming apparatus having an image carrier such as a photoconductor in an image forming apparatus such as a copying machine, a facsimile machine, or a printer, the image carrier is charged, exposed, and exposed in accordance with the rotation of the image carrier. Image formation is performed by performing a development process, a transfer process, and the like. The discharge product generated in the charging step and remaining on the surface of the image carrier, and the residual toner or toner component remaining on the surface of the image carrier after the transfer step are removed through a cleaning process.

  In the cleaning process, as a generally used cleaning method, a method using a cleaning blade such as a rubber blade which is inexpensive, has a simple mechanism, and has excellent cleaning properties is known.

  However, since the cleaning blade is pressed against the image carrier to remove the residue on the surface of the image carrier, stress due to friction between the image carrier surface and the cleaning blade is large, and the cleaning blade is worn. When the image carrier is an organic photoreceptor, the surface layer of the photoreceptor is worn, shortening the life of the cleaning blade and the organic photoreceptor.

  In recent years, in order to meet the demand for higher image quality, the toner used for image formation has become a small particle size. However, in an image forming apparatus using a small particle size toner, residual toner is The ratio of passing through the cleaning blade increases, especially when the dimensional accuracy and assembly accuracy of the cleaning blade are not sufficient, or when the cleaning blade partially oscillates, the toner slips violently, and the cleaning performance Was not sufficient, and the formation hindered the improvement of image quality.

  Therefore, in order to extend the life of the organic photoreceptor and maintain high image quality over a long period of time, it is necessary to reduce the deterioration of members such as the photoreceptor and the cleaning blade due to friction and improve the cleaning performance.

  Therefore, in recent image forming apparatuses, a technique for improving the cleaning property by supplying a lubricant to the image carrier and forming a film of the lubricant is employed. This technique is also excellent in that it has an advantage of suppressing deterioration of the image carrier in the charging step.

  On the other hand, in recent years, in the charging process, there is a charging method using proximity discharge as one of charging methods. In this method, a charging member is brought close to the surface of the image carrier in contact or non-contact, and the surface of the photoreceptor is charged by proximity discharge.

  In recent years, high image quality and downsizing of the device are increasingly desired. However, charging devices are also required to have high image quality and downsizing. Proximity discharge using a charging member in contact with or close to the image carrier The charging device using the method is effective because it does not require a large charging device. In addition, it has excellent performance such as less generation of oxidizing gases such as ozone and NOx.

  In such a proximity charging method, slight contact unevenness between the charging member and the surface of the image carrier, or a gap variation between the charging member and the surface of the image carrier when non-contact is made, the surface of the image carrier is uniform. In recent years, an AC superposition charging method in which an alternating current (AC) component is superimposed on a direct current (DC) component, that is, an AC charging in which an alternating current voltage is superimposed on a direct current voltage. Has come to be used a lot.

  The proximity charging method that performs AC charging can reduce the size and quality of the device, and at the same time suppresses deterioration of the charging member itself because the charging member and the image carrier can be brought into non-contact while maintaining charging uniformity. Therefore, it can be said that this is a very advantageous technology for downsizing, high image quality, and high durability of the apparatus.

  However, it has been found from recent studies that the charging method using proximity discharge deteriorates the surface of the image carrier because discharge concentrates near the surface of the image carrier. The deterioration of the surface of the image carrier due to the proximity discharge occurs even when there is no contact member to the image carrier, unlike mechanical rubbing.

  FIG. 7 shows an image obtained by conducting a charging experiment for about 150 hours continuously, in which only a charging member is placed close to the surface of the image carrier in a non-contact state in order to investigate the deterioration state of the surface of the image carrier due to proximity discharge. It is the result of having measured the change of the film thickness of the support body surface.

  The image carrier used here is an organic photoreceptor in which polycarbonate is contained as a binder resin in the charge transport layer on the surface, and all members that contact the photoreceptor are removed, and an AC bias is superimposed on a DC bias. Charging was performed using a non-contact charging roller to which a voltage was applied.

  As a result, it was found that the amount of abrasion of the film on the surface of the photoconductor gradually increased and the film thickness of the photoconductor gradually decreased. The mechanism of film thickness reduction is currently under investigation and is not clarified. However, when a photoconductor with a reduced film thickness was analyzed, carboxylic acids, etc., that were thought to have decomposed the polycarbonate that composes the photoconductor were detected. It was done.

  As described above, since a substance that is considered to have decomposed components constituting the photoconductor by proximity discharge was detected, the following may be considered as a mechanism for reducing the film thickness of the photoconductor.

  8A and 8B show the state of the surface of the photoconductor 120 when the surface of the photoconductor 120 as the image carrier is deteriorated by the proximity discharge, and the state where the charging roller 191 is opposed to the surface of the photoconductor 120 with a minute gap. It is explanatory drawing shown taking as an example.

  As shown in FIG. 8A, when proximity discharge is performed, the energy of particles (ozone, electrons, excited molecules, ions, plasma, etc.) generated by the discharge is generated on the surface of the photoconductor 120 in the discharge region on the surface of the photoconductor 120. The charge transport layer 120a is irradiated.

  This energy is resonated and absorbed by the binding energy of the molecules constituting the surface of the photoconductor 120, and as shown in FIG. 8B, the charge transport layer 120a has a decrease in molecular weight due to breakage of the resin molecular chain, and entanglement of the polymer chain. It is considered that the charge transport layer 120a gradually decreases its film thickness due to chemical degradation such as a decrease in the degree of evaporation and resin evaporation. Under such circumstances, when the surface of the photoconductor 120 is mechanically rubbed with a cleaning blade or the like, the wear of the photoconductor 120 is further promoted.

  In AC charging, positive and negative discharges of several hundred to several thousand times per second are repeated between the charging member and the image carrier depending on the frequency, so that the surface of the image carrier is activated and the surface of the image carrier and the toner are activated. Adhesive force between the two increases, which may be disadvantageous for cleaning performance. Furthermore, in recent years, the diameter of toner and the spherical shape have been promoted from the viewpoint of high image quality, and the margin for cleaning performance has been decreasing.

As described above, the problems of the cleaning property and the wear of the image carrier are remarkable under AC charging, and it is a big problem to achieve both of them stably.
As a means for solving these problems, as described above, a technique of applying a lubricant to the surface of the image carrier is effective.

  When a lubricant is applied to the image carrier, the AC charging energy is first absorbed by the lubricant, so that it is difficult to reach the image carrier and the image carrier is protected. Since the AC charging energy is large, the effect of protecting the surface of the image carrier by applying the lubricant is high. As described above, the application of the lubricant has an effect of suppressing the deterioration of the image carrier due to AC charging, as well as ensuring the cleaning performance by reducing the deterioration of the members such as the image carrier and the cleaning blade due to friction.

  As such a technique, for example, in [Patent Document 1] to [Patent Document 4], a solid lubricant such as zinc stearate is used as a lubricant for protecting the image carrier from mechanical rubbing and chemical deterioration. A configuration provided with means for applying is disclosed.

JP 2002-156877 A JP 2002-244516 A JP 2004-341480 A Japanese Patent Laying-Open No. 2005-115311

  However, these means exhibit an excellent effect on both the cleaning performance and the image carrier wear, but by using such means, the lubricant itself passes through the cleaning blade and adheres to the charging member. A new problem has occurred. If these substances adhere and accumulate on the charging member, they appear as abnormal images such as black stripes, which is not preferable.

  In order to deal with the contamination of the charging member by such a lubricant, there has been only a means for adjusting the amount of the lubricant applied so far, and it has been difficult to achieve both the wear of the image carrier and the cleaning property. In particular, in the case of the process cartridge, the image carrier has a sufficient life, but there are problems such as the need to replace the charging member early due to contamination of the charging member. At present, there are still few means for realizing a long service life.

  Under such circumstances, as a result of intensive studies, the inventors have found that the contamination of the charging member is caused by electrostatic flight of the powdery lubricant. The configuration has led to a technology that can realize a significant increase in the life of parts around the image carrier without transferring the powdery lubricant to the charging member.

  The present invention can realize a long life of the entire member around the image carrier, such as suppression of wear of the image carrier, maintenance of cleaning properties, and suppression of contamination of the charging member even under charging, particularly under AC charging. It is an object of the present invention to provide an image forming apparatus, a process cartridge, and an image forming method with a simple configuration capable of outputting excellent images.

  In order to achieve the above object, an invention according to claim 1 includes an image carrier, a charging unit for charging the image carrier, a lubricant application unit for applying a lubricant to the image carrier, and the image carrier. An image forming apparatus comprising: a lubricant removing unit that is located downstream of the lubricant applying unit and upstream of the charging unit in a moving direction of the body and for removing powdery lubricant on the image carrier.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the lubricant removing means is disposed in non-contact with the image carrier and electrostatically applies the powdery lubricant on the image carrier. And a lubricant removing member for removing.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the lubricant removing member has a rotatable roller shape.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the lubricant is a fatty acid metal salt.

  The invention according to claim 5 is the image forming apparatus according to claim 4, wherein the fatty acid metal salt is zinc stearate.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the surface layer of the image carrier contains a filler.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, the filler is at least one inorganic filler.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the surface layer of the image carrier has at least a radical polymerizable monomer having no charge transport structure and a charge transport. It consists of the crosslinked layer which hardened | cured the radically polymerizable compound which has a crystalline structure.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect, the radical polymerizable monomer is trifunctional or more and the radical polymerizable compound is monofunctional.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the radical polymerizable compound is one or more of the following general formula (1) or (2).

（式中、Ｒ１は水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、置換もしくは無置換のアリール基、シアノ基、ニトロ基、アルコキシ基、−ＣＯＯＲ７（Ｒ７は水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、又は置換もしくは無置換のアリール基）、ハロゲン化カルボニル基もしくはＣＯＮＲ８Ｒ９（Ｒ８及びＲ９は水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、又は置換もしくは無置換のアリール基を示し、互いに同一であっても異なっていてもよい）を表わし、Ａｒ１、Ａｒ２は置換もしくは未置換のアリーレン基を表わし、同一であっても異なってもよい。Ａｒ３、Ａｒ４は置換もしくは未置換のアリール基を表わし、同一であっても異なってもよい。Ｘは単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わす。Ｚは置換もしくは無置換のアルキレン基、置換もしくは無置換のアラルキレン基、置換もしくは無置換のアルキレンエーテル基、アルキレンオキシカルボニル基を表わす。ｍ、ｎは０〜３の整数を表わす。）

(Wherein R1 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a cyano group, a nitro group, an alkoxy group, -COOR7 (R7 represents A hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), a halogenated carbonyl group, or CONR8R9 (R8 and R9 are hydrogen atoms, halogen atoms, substituted or unsubstituted) An alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, which may be the same or different from each other, and Ar1 and Ar2 represent a substituted or unsubstituted arylene group. Ar3 and Ar4 may be substituted or unsubstituted. X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted aralkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group, and m and n are 0-3. Represents an integer.)

  According to an eleventh aspect of the present invention, in the image forming apparatus according to the ninth or tenth aspect, the radical polymerizable compound is at least one of compounds represented by the following general formula (3).

（式中、ｏ、ｐ、ｑはそれぞれ０又は１の整数、Ｒａは水素原子又はメチル基を表わし、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表わし、同一又は異なっても良い。ｓ、ｔは０〜３の整数を表わす。Ｚａは単結合、メチレン基、エチレン基、

(In the formula, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent substituents other than a hydrogen atom and represent an alkyl group having 1 to 6 carbon atoms, and are the same. S and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）

Represents. )

  The invention according to claim 12 is the image forming apparatus according to any one of claims 8 to 11, wherein the functional group of the radical polymerizable compound is an acryloyloxy group or a methacryloyloxy group. .

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to any one of the eighth to twelfth aspects, the charge transporting structure of the radical polymerizable compound is a triarylamine structure.

  The invention according to claim 14 is the image forming apparatus according to claim 9, wherein the ratio of the molecular weight to the number of functional groups in the radical polymerizable monomer is 250 or less.

  The invention according to claim 15 is the image forming apparatus according to any one of claims 8 to 14, wherein the functional group of the radical polymerizable monomer is an acryloyloxy group and / or a methacryloyloxy group. And

  According to a sixteenth aspect of the present invention, in the image forming apparatus according to any one of the first to fifteenth aspects, the charging method of the image carrier by the charging unit is a contact method or a proximity method, and the charging device The means performs AC charging in which an AC voltage is superimposed on a DC voltage.

  A seventeenth aspect of the invention is used in the image forming apparatus according to any one of the first to sixteenth aspects, and includes at least the image carrier, the charging unit, the lubricant applying unit, and the lubricant. The process cartridge includes a removing unit and is detachable from the main body of the image forming apparatus.

  According to an eighteenth aspect of the present invention, there is provided an image forming method for forming an image using the image forming apparatus according to any one of the first to sixteenth aspects or the process cartridge according to the seventeenth aspect.

  The present invention includes an image carrier, a charging unit that charges the image carrier, a lubricant application unit that applies a lubricant to the image carrier, and a lubricant application unit in the moving direction of the image carrier. Since the image forming apparatus has a lubricant removing means for removing powdery lubricant on the image carrier located on the downstream side and upstream of the charging means, the wear of the image carrier is suppressed and cleaning is performed. Therefore, it is possible to provide an image forming apparatus capable of maintaining the properties and suppressing the contamination of the charging member, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time.

  If the lubricant removing means has a lubricant removing member that is disposed in non-contact with the image carrier and electrostatically removes the powdery lubricant on the image carrier, In order to electrostatically remove the lubricant, it is possible to dispose the lubricant removing member in a non-contact manner on the image carrier. In this case, the lubricant removing member removes the powdery lubricant from the image carrier. And the lubricant removing member does not come into contact with the image carrier, so that the lubricant film on the surface of the image carrier can be prevented from being scraped, and the wear of the image carrier is suppressed and cleaned. Therefore, it is possible to provide an image forming apparatus capable of maintaining the properties and suppressing the contamination of the charging member, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time.

  If the lubricant removing member is in the form of a rotatable roller, powdery lubricant can be removed on the entire peripheral surface of the roller-like lubricant removing member, and image carrier wear is suppressed. It is possible to provide an image forming apparatus capable of maintaining cleanability, suppressing contamination of the charging member, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time. it can.

  If the lubricant is a fatty acid metal salt, it is possible to suppress image carrier wear, maintain cleaning properties, and suppress charging member contamination with a lubricant excellent in lubricity and anti-charge wear properties. Therefore, it is possible to provide an image forming apparatus capable of realizing a long life of the entire member around the image carrier and outputting a good image over a long period of time.

  If the fatty acid metal salt is zinc stearate, it is possible to suppress image carrier wear, maintain cleanability, and suppress charging member contamination with a lubricant that is particularly excellent in lubricity and anti-static wear. Therefore, it is possible to provide an image forming apparatus capable of extending the life of the entire members around the image carrier and outputting a good image over a long period of time.

  If the surface layer of the image carrier contains a filler, irregularities are formed on the surface of the image carrier. For example, when the lubricant is stretched with a blade, the lubricant is applied to the surface of the image carrier by the filler. Since it is trapped in the formed groove, the lubricant is easily held on the image carrier, and the blade does not adhere due to the unevenness of the surface of the image carrier, so that a gap is easily generated between the blade and the surface of the image carrier. Therefore, the lubricant can be present in a more appropriate amount and evenly, and its function can be demonstrated more satisfactorily with a small amount of lubricant, and the wear resistance of the surface layer is improved. Image bearing member wear can be suppressed, cleaning performance can be maintained, charging member contamination can be suppressed, the life of the entire member around the image bearing member can be extended, and a good image can be output over a long period of time. It is possible to provide the forming apparatus.

  If the filler is at least one inorganic filler, irregularities are formed on the surface of the image carrier. For example, when the lubricant is stretched by a blade, the lubricant is formed on the surface of the image carrier by the filler. Since it is trapped in the groove, the lubricant is easily held on the image carrier, and the blade does not adhere due to unevenness on the surface of the image carrier, so that a gap is easily formed between the blade and the surface of the image carrier, and lubrication is performed. The agent can be present in a more appropriate amount and evenly, and its function can be performed even better with a small amount of lubricant, and the inorganic filler has excellent wear resistance, so that the surface layer is resistant to abrasion. The wear property is particularly improved, and even with a small amount of lubricant, the wear of the image carrier can be suppressed, the cleaning property can be maintained, and the charging member can be prevented from being stained. Service life can be realized, it is possible to provide an output image forming apparatus capable of a good image for a long time.

  If the surface layer of the image carrier comprises a crosslinked layer obtained by curing at least a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure, the surface of the image carrier By configuring the layer with a material suitable for this, it is possible to suppress wear of the image carrier, maintain cleanability, and suppress contamination of the charging member, thereby realizing a long life of the entire members around the image carrier. It is possible to provide an image forming apparatus capable of outputting a good image over a long period of time.

  Assuming that the radical polymerizable monomer is trifunctional or more and the radical polymerizable compound is monofunctional, the surface layer of the image carrier is made of a material more suitable for this, and the image carrier wear An image forming apparatus capable of suppressing the image quality, maintaining the cleaning property, and suppressing the contamination of the charging member, extending the life of the entire member around the image bearing member, and outputting a good image over a long period of time is provided. be able to.

  Assuming that the radical polymerizable compound is one or more of the following general formula (1) or (2), the surface layer of the image carrier is made of a material more suitable for the image carrier, Providing an image forming apparatus capable of suppressing wear, maintaining cleanability, suppressing contamination of the charging member, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time can do.

（式中、Ｒ１は水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、置換もしくは無置換のアリール基、シアノ基、ニトロ基、アルコキシ基、−ＣＯＯＲ７（Ｒ７は水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、又は置換もしくは無置換のアリール基）、ハロゲン化カルボニル基もしくはＣＯＮＲ８Ｒ９（Ｒ８及びＲ９は水素原子、ハロゲン原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアラルキル基、又は置換もしくは無置換のアリール基を示し、互いに同一であっても異なっていてもよい）を表わし、Ａｒ１、Ａｒ２は置換もしくは未置換のアリーレン基を表わし、同一であっても異なってもよい。Ａｒ３、Ａｒ４は置換もしくは未置換のアリール基を表わし、同一であっても異なってもよい。Ｘは単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わす。Ｚは置換もしくは無置換のアルキレン基、置換もしくは無置換のアラルキレン基、置換もしくは無置換のアルキレンエーテル基、アルキレンオキシカルボニル基を表わす。ｍ、ｎは０〜３の整数を表わす。）

(Wherein R1 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a cyano group, a nitro group, an alkoxy group, -COOR7 (R7 represents A hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), a halogenated carbonyl group, or CONR8R9 (R8 and R9 are hydrogen atoms, halogen atoms, substituted or unsubstituted) An alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, which may be the same or different from each other, and Ar1 and Ar2 represent a substituted or unsubstituted arylene group. Ar3 and Ar4 may be substituted or unsubstituted. X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted aralkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group, and m and n are 0-3. Represents an integer.)

  If the radical polymerizable compound is at least one of the compounds represented by the following general formula (3), the surface layer of the image carrier is made of a material particularly suitable for this, An image forming apparatus capable of suppressing body wear, maintaining cleaning properties, suppressing charging member contamination, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time. Can be provided.

（式中、ｏ、ｐ、ｑはそれぞれ０又は１の整数、Ｒａは水素原子又はメチル基を表わし、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表わし、同一又は異なっても良い。ｓ、ｔは０〜３の整数を表わす。Ｚａは単結合、メチレン基、エチレン基、

(In the formula, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent substituents other than a hydrogen atom and represent an alkyl group having 1 to 6 carbon atoms, and are the same. S and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）

Represents. )

  If the functional group of the radical polymerizable compound is an acryloyloxy group or a methacryloyloxy group, the surface layer of the image carrier is a material suitable for this, and the functional group constitutes the surface layer. By using a material that is specified as a particularly suitable material, it is possible to suppress wear of the image carrier, maintain cleanability, and suppress contamination of the charging member, thereby extending the life of the entire members around the image carrier. And an image forming apparatus capable of outputting a good image over a long period of time.

  If the charge transporting structure of the radical polymerizable compound is a triarylamine structure, the surface layer of the image carrier is a material suitable for this, and the charge transporting structure forms the surface layer. It is possible to suppress wear of the image carrier, maintain cleanability, and suppress contamination of the charging member by extending the life of the entire members around the image carrier. An image forming apparatus that can be realized and can be provided over a long period of time can be provided.

  If the ratio of the molecular weight with respect to the number of functional groups in the radical polymerizable monomer is 250 or less, the surface layer of the image carrier is made of a material suitable for this and has a molecular weight with respect to the number of functional groups in the radical polymerizable monomer. By using a material whose ratio is in a range particularly suitable for constituting the surface layer, it is possible to suppress wear of the image carrier, maintain cleanability, and suppress charging member contamination, and the entire members around the image carrier Thus, it is possible to provide a good image forming apparatus over a long period of time.

  If the functional group of the radical polymerizable monomer is an acryloyloxy group and / or a methacryloyloxy group, the surface layer of the image carrier is a material suitable for this and the functional group constitutes the surface layer. By using a material that is specified as being particularly suitable, it is possible to suppress wear of the image carrier, maintain cleanability, and suppress contamination of the charging member, thereby extending the life of the entire members around the image carrier. And an image forming apparatus capable of outputting a good image over a long period of time can be provided.

  If the charging method of the image carrier by the charging unit is a contact method or a proximity method, and the charging unit performs AC charging in which an AC voltage is superimposed on a DC voltage, it is small and generates gas. Even with AC charging that is easy to apply a load to the image carrier, it is possible to suppress the wear of the image carrier, maintain the cleaning property, It is possible to provide an image forming apparatus that can perform suppression, can achieve a long life of the entire member around the image carrier, and can output a good image over a long period of time.

  The present invention is used in the image forming apparatus according to any one of claims 1 to 16, and includes at least the image carrier, the charging unit, the lubricant applying unit, and the lubricant removing unit. Since it is in a process cartridge that is integrated and detachable from the main body of the image forming apparatus, it is possible to suppress image carrier wear, maintain cleanability, and suppress charging member contamination. It is possible to provide a process cartridge capable of realizing a long life as a whole, outputting a good image over a long period of time, and having excellent exchangeability of an image carrier or the like.

  The present invention resides in an image forming apparatus according to any one of claims 1 to 16 or an image forming method for forming an image using the process cartridge according to claim 17, so that the wear of the image carrier is suppressed. It is possible to provide an image forming method capable of maintaining cleaning properties, suppressing contamination of the charging member, extending the life of the entire member around the image carrier, and outputting a good image over a long period of time. it can.

  FIG. 1 shows an outline of an image forming apparatus to which the present invention is applied. The image forming apparatus 100 is a color laser printer, but may be other types of image forming apparatuses such as other types of printers, facsimile machines, copiers, and multifunction machines of copiers and printers. The image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. The image forming apparatus 100 can form an image using plain paper generally used for copying, OHP sheets, thick paper such as cards and postcards, and envelopes as sheet-like recording media. .

  The image forming apparatus 100 includes photosensitive drums 20Y and 20M which are latent image carriers as image carriers that can form images as images corresponding to colors separated into yellow, magenta, cyan, and black, respectively. , 20C, 20BK are arranged in parallel, in other words, a tandem system is adopted.

  The photosensitive drums 20Y, 20M, 20C, and 20BK that are the surface moving members are rotatably supported by a frame (not shown) of the main body 99 of the image forming apparatus 100, and in this order from the upstream side in the A1 direction that is the moving direction of the transfer belt 11. Are lined up. Y, M, C, and BK added after the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black.

  Each of the photosensitive drums 20Y, 20M, 20C, and 20BK is an image forming unit for forming yellow (Y), magenta (M), cyan (C), and black (BK) images. It is provided in 60C and 60BK.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are positioned on the outer peripheral surface side of the transfer belt 11 as an intermediate transfer member, that is, an endless belt disposed almost at the center in the main body 99, that is, on the image forming surface side. ing.

  The transfer belt 11 is movable in the direction of the arrow A1 while facing the photosensitive drums 20Y, 20M, 20C, and 20BK. Visible images, that is, toner images formed on the respective photosensitive drums 20Y, 20M, 20C, and 20BK are respectively superimposed and transferred onto the transfer belt 11 that moves in the direction of the arrow A1, and then collectively onto the transfer sheet S that is a recording medium. It is designed to be transcribed.

  The lower portion of the transfer belt 11 faces the photosensitive drums 20Y, 20M, 20C, and 20BK, and the opposed portions transfer the toner images on the photosensitive drums 20Y, 20M, 20C, and 20BK. A transfer portion 98 for transferring to the transfer belt 11 is formed.

  In the superimposing transfer to the transfer belt 11, the toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. In such a manner, the voltage is applied by the primary transfer rollers 12Y, 12C12C, and 12BK disposed at positions facing the photosensitive drums 20Y, 20M, 20C, and 20BK across the transfer belt 11, so that the A1 direction upstream side to the downstream side. This is done at different timings.

  The transfer belt 11 is an elastic belt whose entire layer is formed using an elastic member such as a rubber agent. The transfer belt 11 may be a single-layer elastic belt, may be an elastic belt using a part of the elastic belt, or a conventionally used fluorine-based resin, polycarbonate resin, or polyimide resin. Or an inelastic belt may be used.

  Each of the transfer belts 11 has a detent guide (not shown) as a detent member at each edge thereof. The offset guide is provided to prevent the transfer belt 11 from being biased in any direction perpendicular to the paper surface in FIG. 1 when the transfer belt 11 rotates in the A1 direction. The stopper guide is made of urethane rubber, but can be made of various rubber materials such as silicon rubber.

  The image forming apparatus 100 is disposed in the main body 99 so as to oppose the four image forming units 60Y, 60M, 60C, and 60BK and the respective photosensitive drums 20Y, 20M, 20C, and 20BK. A transfer belt unit 10 as an intermediate transfer unit provided; a secondary transfer roller 5 as a secondary transfer bias roller as a transfer member which is disposed opposite to the transfer belt 11 and is driven by the transfer belt 11; And an optical scanning device 8 that is an optical writing unit as a latent image forming unit disposed facing the lower side of the image forming units 60Y, 60M, 60C, and 60BK.

  The image forming apparatus 100 also has a sheet as a sheet feeding cassette in which a large number of transfer sheets S transported between the photosensitive drums 20Y, 20M, 20C, and 20BK and the transfer belt 11 can be stacked in the main body 99. Each photosensitive drum 20Y is fed at a predetermined timing in accordance with the toner image forming timing of the feeding device 61 and the recording sheet S conveyed from the sheet feeding device 61 by the image forming units 60Y, 60M, 60C, and 60BK. , 20M, 20C, 20BK and the transfer belt 11 and the registration roller pair 4 fed toward the transfer portion 98, and a sensor (not shown) for detecting that the leading edge of the transfer paper S has reached the registration roller pair 4. is doing.

  The image forming apparatus 100 also includes a fixing device 6 as a roller fixing type fixing unit for fixing the toner image on the transfer sheet S to which the toner image is transferred, and a fixed transfer sheet S in the main body 99. A discharge roller 7 as a pair of discharge rollers for discharging to the outside of the main body 99, and toner bottles 9Y and 9M disposed above the transfer belt unit 10 and filled with toner of each color of yellow, cyan, magenta, and black. , 9C, 9BK, and a discharge tray 17 on the upper side of the main body 99 on which the transfer sheets S discharged from the main body 99 by the discharge roller 7 are stacked.

  The image forming apparatus 100 also includes a driving device (not shown) that rotationally drives the photosensitive drums 20Y, 20M, 20C, and 20BK, and a power source as a bias applying unit (not shown) that applies a secondary transfer bias to the secondary transfer roller 5. The control unit includes a bias control unit, and a control unit including a CPU, a memory, and the like that control the overall operation of the image forming apparatus 100 based on detection results by various detection units.

  In addition to the transfer belt 11, the transfer belt unit 10 includes primary transfer rollers 12Y, 12M, 12C, and 12BK as primary transfer bias rollers, and a drive roller 72 that is a drive member around which the transfer belt 11 is wound. A cleaning counter roller 74 as a tension roller, a tension roller 75 that stretches the transfer belt 11 together with the driving roller 72 and the cleaning counter roller 74, and a surface of the transfer belt 11 that is disposed facing the transfer belt 11 to clean the transfer belt 11. And a cleaning device 13 as a belt cleaning device.

  The transfer belt unit 10 also includes a drive system (not shown) that rotationally drives the drive roller 72, and a power source and bias control as a bias application unit (not shown) that applies a primary transfer bias to the primary transfer rollers 12Y, 12M, 12C, and 12BK. Means.

  The primary transfer rollers 12Y, 12M, 12C, and 12BK press the transfer belt 11 from the back surface thereof toward the photosensitive drums 20Y, 20M, 20C, and 20BK to form primary transfer nips.

  In each primary transfer nip, a primary transfer electric field is formed between the photosensitive drums 20Y, 20M, 20C, and 20BK and the primary transfer rollers 12Y, 12M, 12C, and 12BK due to the influence of the primary transfer bias. . The toner images of the respective colors formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are primarily transferred onto the transfer belt 11 due to the influence of the primary transfer electric field and nip pressure.

The driving roller 72 is in contact with the secondary transfer roller 5 via the transfer belt 11 to form a secondary transfer nip.
The cleaning counter roller 74 has a function as a tension roller as a pressure member that gives the transfer belt 11 a predetermined tension suitable for transfer.

  Although not shown in detail, the cleaning device 13 includes a cleaning brush and a cleaning blade disposed so as to face and contact the transfer belt 11, and remove foreign matters such as residual toner on the transfer belt 11. The transfer belt 11 is cleaned by scraping and removing with a cleaning brush and a cleaning blade.

The sheet feeding device 61 accommodates a plurality of transfer sheets S in a state of a stack of transfer sheets, and is disposed below the optical scanning device 8 below the main body 99. The sheet feeding device 61 has a feeding roller 3 as a sheet feeding roller pressed against the upper surface of the uppermost transfer sheet S, and the feeding roller 3 is driven to rotate counterclockwise at a predetermined timing. As a result, the uppermost transfer sheet S is fed toward the registration roller pair 4.
The transfer sheet S sent out from the sheet feeding device 61 reaches the registration roller pair 4 through the sheet feeding path and is sandwiched between the rollers of the registration roller pair 4.

  The fixing device 6 includes a heating roller 62 having a heat source therein, and a belt unit 63 pressed against the heating roller 62. The belt unit 63 includes an endless fixing belt 64 that is pressed against the heating roller 62 and three rollers 65, 66, and 67 that endlessly move the fixing belt 64 while stretching it.

  The fixing device 6 passes the transfer sheet S carrying the toner image in a manner of sandwiching the transfer sheet S between the heating roller 62 and the belt unit 63 so as to sandwich the carried toner image by the action of heat and pressure. It is fixed on the surface of the transfer paper S.

  The yellow, cyan, magenta, and black toners in the toner bottles 9Y, 9M, 9C, and 9BK are provided in the image forming units 60Y, 60M, 60C, and 60BK, respectively, by a predetermined replenishment amount through a conveyance path (not shown). 2 is supplied to the developing device 80Y shown in FIG.

  The configuration of the image forming units 60Y, 60M, 60C, and 60BK will be described as a representative of the configuration of the image forming unit 60Y that includes the photosensitive drum 20Y. Since the configurations of the other image forming units are substantially the same, in the following description, for the sake of convenience, reference numerals corresponding to the reference numerals assigned to the configuration of the image forming unit 60Y are used for the configurations of the other image forming units. The detailed description will be omitted as appropriate.

  As shown in FIG. 2 or FIG. 3, the image forming unit 60Y provided with the photosensitive drum 20Y has a primary transfer roller 12Y around the photosensitive drum 20Y along its rotation direction B1, which is the clockwise direction in the drawing. A lubricating substance supply device 40Y as a lubricant applying means for applying a lubricating substance 42Y as a lubricant to the photosensitive drum 20Y, a cleaning device 70Y as a drum cleaning apparatus as a cleaning means, and a static elimination means. A static eliminator 35Y, a lubricating substance removing device 50Y as a powder lubricant removing device as a lubricant removing device, a charging device 90Y as a charging device as a charging device, and a developing device as a developing unit as a developing device. A developing device 80Y.

  As shown in FIG. 2, the photosensitive drum 20Y, the lubricating substance supply device 40Y, the cleaning device 70Y, the static eliminating device 35Y, the lubricating substance removing device 50Y, the charging device 90Y, and the developing device 80Y are integrated. The process cartridge 68Y is configured. The process cartridge 68Y is detachable from the main body 99. Making a process cartridge in this way is very preferable because it can be handled as a replacement part, so that the maintainability is remarkably improved.

  As shown in FIG. 2 or FIG. 4, the charging device 90Y is a uniform charging unit that uniformly charges the surface of the photosensitive drum 20Y, and is a charging device that is disposed to face the surface of the photosensitive drum 20Y. A charging roller 91Y as a member, a brush roller 92Y disposed in contact with the charging roller 91Y, a spacer 94Y wound on the surface of the charging roller 91Y, and an urging member that biases the charging roller 91Y toward the photosensitive drum 20Y. A spring 95Y, which is a pressure spring as a biasing member, a case 93Y accommodating these, a power supply 96Y that applies a voltage to the charging roller 91Y, and a driving means (not shown) that rotationally drives the brush roller 92Y. .

  The charging roller 91Y occupies the central portion of the photosensitive drum 20Y in the direction of the rotation axis of the photosensitive drum 20Y, which is the longitudinal direction of the charging roller 91Y, and is longer than the length of the image forming area 20Y1 where a toner image is formed.

  The charging roller 91Y includes a roller portion 98Y having a cylindrical shape and shaft portions 97Y protruding from both ends of the roller portion 98Y. Although not shown, the roller portion 98Y includes a resistance adjustment layer formed with a surface layer and a cored bar as a conductive support formed with the resistance adjustment layer on the peripheral surface thereof. The core metal and the shaft portion 97Y are integrally formed. The shaft portion 97Y is rotatably supported by the case 93Y, and the roller portion 98Y rotates as the shaft portion 97Y rotates. Details of the resistance adjustment layer will be described later.

  The spacers 94Y are disposed in the vicinity of both end portions of the circumferential surface of the roller portion 98Y, and are in contact with non-image forming regions 20Y2 that occupy both end portions of the photosensitive drum 20Y and are located on both sides of the image forming region 20Y1. Thus, by bringing the two spacers 94Y into contact with the non-image forming regions 20Y2 at both ends of the photosensitive drum 20Y, a small gap G is formed between the photosensitive drum 20Y and the charging roller 91Y, in other words, the roller portion 98Y. Is formed. The gap G is formed not only in the non-image forming area 20Y2 but also in the image forming area 20Y1, and the charging roller 91Y is not in contact with the photosensitive drum 20Y in a portion facing the image forming area 20Y1.

  The gap G is configured such that the distance at the closest portion between the charging roller 91Y and the photosensitive drum 20Y is maintained at 5 to 100 μm by adjusting the thickness of the spacer 94Y and the like. A more preferable range of the gap G is 30 to 65 μm, and in this embodiment, it is set to 50 μm.

  The spring 95Y is in contact with each shaft portion 97Y and presses the charging roller 91Y against the photosensitive drum 20Y. As a result, the minute gap G is accurately maintained, and the charging roller 91Y rotates with the surface of the photosensitive drum 20Y via the spacer 94Y.

  The brush roller 92Y is rotationally driven by a driving unit, and removes foreign matters such as toner adhering to the charging roller 91Y by rubbing the charging roller 91Y, and maintains the performance of the charging roller 91Y with time.

  The power supply 96Y applies an AC voltage, which is an alternating voltage obtained by superimposing an AC voltage (AC voltage) on a DC voltage (DC voltage), to the charging roller 91Y. The charging roller 91Y is applied to the photosensitive drum 20Y by proximity discharge in the gap G. On the other hand, AC charging is performed. Here, the charging device 90Y is a charging device that performs AC charging, and a proximity charging device that performs proximity discharging.

  By superimposing the AC voltage on the DC voltage, even if the gap G fluctuates, the influence of variations in the charging potential is suppressed, and the charging potential of the photosensitive drum 20Y can be held stably and uniformly. .

  Further, since the proximity method does not cause disturbance such as scraping of the lubricating material 42Y, the disturbance does not affect the image and contributes to high durability.

  The surface of the charging roller 91Y is desirably hard. This is because when the charging roller 91Y locally and suddenly contacts the surface of the photosensitive drum 20Y, a disturbance such as scraping of the lubricating material 42Y occurs, and this disturbance affects the image. This is because it is suitable to use a hard member with less deflection when using such a non-contact charging method.

  For these reasons, the resistance adjustment layer is formed of a thermoplastic resin composition (polyethylene, polypropylene, polymethyl methacrylate, polystyrene, and copolymers thereof, etc.) in which a polymer type ion conductive agent is dispersed, and resistance adjustment is performed. The surface of the layer may be a cured film treated with a curing agent. The cured film treatment is performed, for example, by immersing the resistance adjustment layer in a treatment solution containing an isocyanate-containing compound, but may be performed by forming a cured treatment film layer on the surface of the resistance adjustment layer.

  A rubber member can also be used as a member constituting the charging roller 91Y. However, if the member is easily deformed like a rubber member, it is difficult to maintain the gap G uniformly, and the charging roller 91Y bends depending on image forming conditions. Since the central portion may suddenly contact the surface of the photosensitive drum 20Y, it is not preferable. In this regard, in this embodiment, in order to prevent such deflection, the charging roller 91Y is made hard so that the diameter of the charging roller 91Y is 10 mm (φ10 mm).

  As a method for charging the photosensitive drum 20Y, a charging member such as the charging roller 91Y is used in addition to the proximity method in which the charging roller 91Y is arranged in non-contact with the photosensitive drum 20Y as in the charging device 90Y of this embodiment. There is a contact charging method, that is, a contact method in which the photosensitive drum 20Y is placed in contact therewith.

  In the contact method, it is preferable to use an elastic member that improves the contact property with the surface of the photoreceptor drum 20Y and does not apply mechanical stress to the photoreceptor drum 20Y. However, when an elastic member is used, the charging nip width is widened, which makes it easier for the lubricating substance 42Y to adhere to the charging roller side. Therefore, it is more advantageous to adopt the proximity method for high durability.

  In addition, the charging method includes a non-contact charging method using a corona charger, etc., but the use of the contact method or the proximity method generates less oxidizing gas such as ozone and NOx. Since a large space is not required, it is advantageous for downsizing of an image forming apparatus and a tandem system. Therefore, the contact method or the proximity method is preferable to the non-contact charging method using a corona charger or the like.

  The brush roller 92Y removes the foreign matter adhering to the charging roller 91Y from the charging roller 91Y, but another cleaning member may be provided instead of the brush roller 92Y.

  The developing device 80Y includes a developing case 85Y having an opening at a portion facing the photoconductor drum 20Y, and the photosensitive drum 20Y so as to expose a part of its peripheral surface so as to face the photoconductor drum 20Y from the opening. And a developing blade 81Y disposed in close proximity to each other and a doctor blade 82Y that regulates the developer on the developing roller 81Y to a certain height.

  The developing device 80Y is also disposed below the developing case 85Y so as to face each other, and includes a first transport screw 83Y and a second transport screw 84Y for stirring the developer and supplying the developer to the developing roller 81Y. And a partition wall 87Y provided between the first transport screw 83Y and the second transport screw 84Y.

  The developing device 80Y also rotationally drives a toner concentration sensor 86Y disposed below the second conveyance screw 84Y and a partition wall 87Y provided between the first conveyance screw 83Y and the second conveyance screw 84Y. Drive means (not shown), and bias application means (not shown) for applying a developing bias of a direct current component.

  In the developing case 85Y, the partition wall 87Y separates the first supply unit that accommodates the developing roller 81Y and the first conveyance screw 83Y and the second supply unit that accommodates the second conveyance screw 84Y. Has been.

  The first transport screw 83Y is rotationally driven by a driving unit, and supplies the developer in the first supply unit to the developing roller 81Y while transporting the developer from the back side to the front side in FIG. The developer conveyed to the vicinity of the end in the first supply unit by the first conveyance screw 83Y enters the second supply unit through an opening (not shown) formed in the partition wall 87Y.

  In the second supply unit, the second transport screw 84Y transports the developer sent from the first supply unit in the direction opposite to that of the first transport screw 83Y by being rotationally driven by the driving unit. The developer transported to the vicinity of the end of the second supply unit by the second transport screw 84Y returns to the first supply unit through another opening (not shown) provided in the partition wall 87Y.

  The developer in the developing case 85Y is a two-component developer including a magnetic carrier and a negatively charged yellow toner. The developer is supplied with and supplied with yellow toner from the toner bottle 9Y. The supplied yellow toner and the developer are agitated and mixed by the conveying screw 83Y and the second conveying screw 84Y while being agitated and conveyed, frictionally charged, and supplied and carried on the developing roller 81Y.

  The developing roller 81Y whose developer carrying amount is regulated by the doctor blade 82Y and whose layer thickness is regulated is rotated between the developing roller 81Y and the photosensitive drum 20Y by the rotation in the direction of the arrow C1 and the developing bias by the bias applying means. The developer whose amount is adjusted to an appropriate amount by the doctor blade 82Y is carried to the developing area of the toner, and the yellow toner in the developer is electrostatically transferred to the electrostatic latent image formed on the surface of the photosensitive drum 20Y. The electrostatic latent image is visualized as a yellow toner image.

The developer that has consumed the yellow toner by the development is returned into the developing case 85Y as the developing roller 81Y rotates.
In this embodiment, the DC component developing bias is applied by the bias applying means. However, the developing bias may be an AC component, or an AC component superimposed on the DC component.

  The optical scanning device 8 shown in FIG. 1 includes a light source 31, a polygon mirror 32, an fθ lens 33, a reflection mirror 34, and the like. As shown in FIG. 2, the optical scanning device 8 irradiates a region between the charged region and the developing region on the photosensitive drum 20Y while scanning the light-modulated and deflected laser light L, thereby charging the device 90Y. The surface to be scanned on the surface of the photosensitive drum 20Y after being charged by the exposure is exposed by spot irradiation, and an electrostatic latent image corresponding to image information that is visualized as a yellow toner image by the developing device 80Y is written. It has become.

  The cleaning device 70Y has a cleaning case 76Y having an opening in a portion facing the photoconductor drum 20Y, and a cleaning that scrapes and collects the transfer residual toner and the carrier on the photoconductor drum 20Y in contact with the photoconductor drum 20Y. And a blade 78Y.

  The cleaning device 70Y is also rotatably supported by the cleaning case 76Y, scraped off by the cleaning blade 78Y, and a part of a discharge path (not shown) for transporting the removed transfer residual toner and the like toward the developing device 80Y. The discharge screw 79Y is configured.

  The inside of the cleaning device 70Y is a sealed space by the cleaning case 76Y, the cleaning blade 78Y, and the photosensitive drum 20Y, and has a structure in which the collected transfer residual toner and the like are not scattered inside the image forming apparatus 100.

The lubricating substance supply device 40Y includes a case 41Y that is open only on the side facing the surface of the photosensitive drum 20Y, and a lubricating substance 42Y as a lubricant that is a solid lubricant housed in the case 41Y and formed into a bar shape. A brush roller 47Y as a fur brush as an application member for applying and supplying the lubricant 42Y to the photosensitive drum 20Y, and a pressure spring as an elastic member for pressing the lubricant 42Y against the brush roller 47Y. And a spring 48Y.
The brush roller 47Y is in contact with the photosensitive drum 20Y at the tip of the brush.

  The lubricating substance supply device 40Y configured as described above rotates the brush roller 47Y about its axis to scrape off the lubricating substance 42Y, and once pumps up the scraped lubricating substance 42Y with the surface of the photosensitive drum 20Y. Is carried and conveyed to the contact position, and is applied and supplied to the photosensitive drum 20Y.

  The lubricant 42Y applied to the photoconductor drum 20Y is stretched to the surface of the photoconductor drum 20Y by the cleaning blade 78Y at the same time as the cleaning blade 78Y removes the transfer residual toner and the like from the surface of the photoconductor drum 20Y, and the lubricant. A film is formed.

  Even if the lubricating material 42Y is scraped off by the brush roller 47Y over time, the amount of the lubricating material 42Y becomes very small because the spring 48Y presses the lubricating material 42Y against the brush roller 47Y with a predetermined pressure. However, it is always pumped up uniformly by the brush roller 47Y, and the lubricating material 42Y contacts the brush roller 47Y until it is completely consumed.

  The film formed on the surface of the photosensitive drum 20Y by the lubricating substance 42Y has a function of preventing the deterioration of the surface of the photosensitive drum 20Y due to the proximity discharge, and the lubricating substance supply device 40Y functions as a discharge deterioration preventing unit. To do. The deterioration here refers to both wear of the photosensitive drum 20Y due to discharge, acceleration of the wear, and activation of the surface of the photosensitive drum 20Y.

In addition, the coating prevents deterioration such as wear caused by friction between the photosensitive drum 20Y and the cleaning blade 78Y, and the lubricating substance supply device 40 functions as a friction deterioration preventing unit.
As described above, the lubricating substance supply device 40 applies all of the deterioration by applying the lubricating substance 42Y to the surface of the photoreceptor drum 20Y.

  In order to satisfactorily perform such a function, the lubricating substance 42Y includes, for example, lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, Fatty acid metal salts such as copper palmitate and zinc linolenate, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoro Fluorine-based resins such as ethylene-oxafluoropropylene copolymer can be mentioned, and a metal stearate having a large effect of reducing the friction coefficient of the photoconductor drum 20Y and zinc stearate are more preferable.

  The lubricating substance supply device 40Y is provided with a blade supported by supporting it on the case 41Y on the downstream side of the brush roller 47Y in the rotation direction B1 of the photosensitive drum 20Y. The lubricant material 42Y applied to the photosensitive drum 20Y may be stretched to form a lubricant film. Such a blade is employed in a modification described later.

The lubricating substance removing device 50Y has been developed and adopted under the following knowledge.
That is, as a result of observing in detail how the lubricating material such as the lubricating material 42Y exists on the image carrier such as the photosensitive drum 20Y, the lubricating material is scraped off with a brush such as the brush roller 47Y. Immediately after, it was present in the form of powder, and this was stretched into a film shape when passing through each process, particularly the blade portion such as the cleaning blade 78Y, and it was found that lubricity was exhibited. In addition, the lubricating material present in the form of a film does not transfer to the charging member such as the charging roller 91Y, but a fine powdery lubricating material that passes through the blade such as the cleaning blade 78Y is used as the charging roller 91Y or the like. It was clarified that the material was transferred to the charging member by an electric field to cause contamination.

Therefore, the lubricating substance removing device 50Y has the following configuration.
That is, the lubricating substance removing device 50Y has the same structure as the charging device 90Y, and as shown in FIG. 2 or FIG. 4, as a lubricant removing member disposed facing the surface of the photosensitive drum 20Y. The roller-shaped removal roller 51Y, the cleaning roller 52Y disposed in contact with the removal roller 51Y, the spacer 54Y wound on the surface of the removal roller 51Y, and the removal roller 51Y are urged toward the photosensitive drum 20Y. A spring 55Y that is a pressure spring as an urging member, a case 53Y that accommodates them, a power source 56Y that applies a voltage to the removal roller 51Y, and a driving means (not shown) that rotationally drives the cleaning roller 52Y. Yes.

  The removal roller 51Y occupies the center of the photosensitive drum 20Y in the longitudinal axis direction of the photosensitive drum 20Y, and is longer than the length of the image forming area 20Y1 where a toner image is formed.

  The removal roller 51Y includes a roller portion 58Y having a columnar shape, and shaft portions 57Y protruding from both ends of the roller portion 58Y. Although not shown, the roller portion 58Y includes a resistance adjustment layer formed with a surface layer and a cored bar as a conductive support formed with the resistance adjustment layer on the peripheral surface thereof. The core bar and the shaft portion 57Y are integrally formed.

  The shaft portion 57Y is rotatably supported by the case 53Y, and the roller portion 58Y rotates as the shaft portion 57Y rotates. Therefore, the removal roller 41Y is rotatable. Since the resistance adjustment layer is the same as the resistance adjustment layer of the charging roller 91Y, description thereof is omitted.

  The spacers 54Y are disposed in the vicinity of both end portions of the peripheral surface of the roller portion 58Y, and are in contact with the non-image forming regions 20Y2 that occupy both end portions of the photosensitive drum 20Y and are located on both sides of the image forming region 20Y1. Thus, by bringing the two spacers 54Y into contact with the non-image forming regions 20Y2 at both ends of the photosensitive drum 20Y, a small gap G is formed between the photosensitive drum 20Y and the removal roller 51Y, in other words, the roller portion 58Y. Is formed. The gap G is formed not only in the non-image forming area 20Y2 but also in the image forming area 20Y1, and the removal roller 51Y is not in contact with the photosensitive drum 20Y in a portion facing the image forming area 20Y1.

  The gap G is configured such that the distance at the closest portion between the removal roller 51Y and the photosensitive drum 20Y is maintained at 5 to 100 μm by adjusting the thickness of the spacer 54Y and the like. A more preferable range of the gap G is 30 to 65 μm, and in this embodiment, it is set to 50 μm.

  The spring 55Y is in contact with each shaft portion 57Y and presses the removal roller 51Y against the photosensitive drum 20Y. As a result, the minute gap G is accurately maintained, and the removal roller 51Y rotates with the surface of the photosensitive drum 20Y via the spacer 54Y.

  The cleaning roller 52Y uses melamine resin foam as its material, but the material is not limited to this, and generally a material excellent in powder removal may be used, for example, electrostatic flocking of divided fine fibers, A brush-like one like the brush roller 92Y or other pad-like ones may be used. The cleaning roller 52Y is rotationally driven by a driving means, and the powdery lubricant 42Y and the like adhering to the removal roller 51Y is removed by rubbing the removal roller 51Y, and the performance of the removal roller 51Y is maintained over time. Thereby, the contamination of the charging roller 91Y can be further reduced. The cleaning roller 52Y can be omitted as appropriate.

The power supply 56Y applies a DC voltage of 500 V to the removal roller 51Y, thereby causing the powdery lubricant 42Y to fly from the photosensitive drum 20Y to the removal roller 51Y and to be removed.
Although the removability of the lubricating material 42Y of the powder varies depending on the applied voltage, the powder of the fatty acid metal salt is generally negatively charged when rubbed with a blade such as the cleaning blade 78Y, and therefore a positive electric field is applied. Further, if an excessive voltage is applied, a discharge can be caused to deteriorate the photosensitive drum 20Y, so the applied voltage is 50 to 1000V, preferably 100 to 700V.

  The surface of the removing roller 51Y is preferably hard. This is because when the removal roller 51Y locally and suddenly contacts the surface of the photosensitive drum 20Y, disturbance such as scraping of the film-like lubricating material 42Y occurs, and this disturbance affects the image. This is because it is suitable to use a hard member with less deflection.

  Therefore, a rubber member can also be used as a member constituting the removal roller 51Y. However, if the member is easily deformed like a rubber member, it is difficult to maintain the gap G uniformly, and the removal roller 51Y bends depending on image forming conditions. Since the central portion may suddenly come into contact with the surface of the photosensitive drum 20Y, it is preferable to use a metal member such as the above-described core metal or other hard member.

  The removing roller 51Y may employ a contact system that contacts the photoconductor drum 20Y. However, the contact system removes the powdery lubricating substance 42Y and has an effect of fixing the surface to the photoconductor drum 20Y. As in this embodiment, the non-contact method in which the photosensitive drum 20Y is arranged in a non-contact manner, that is, the proximity method is preferable.

  The static eliminator 35Y includes a static eliminator 36Y that applies a predetermined voltage to the photosensitive drum 20Y after passing through the cleaning device 70Y, and a case 37Y that accommodates the static eliminator 36Y, and the transfer residual toner is removed by the cleaning device 70Y. The residual charge on the surface of the photosensitive drum 20Y after being removed is removed.

  In such an image forming unit 60Y, the surface of the photosensitive drum 20Y is uniformly charged by the charging device 90Y as it rotates in the B1 direction, and yellow is detected by exposure scanning of the laser light L from the optical scanning device 8. An electrostatic latent image corresponding to the color is formed, the electrostatic latent image is developed with yellow toner by the developing device 80Y, and the yellow toner image obtained by development is developed in the A1 direction by the primary transfer roller 12Y. The primary transfer is performed on the moving transfer belt 11, and the lubricating substance 42Y is supplied by the lubricating substance supply device 40Y. The residual transfer toner remaining after the transfer is satisfactorily removed by the cleaning device 70Y, and the residual charge is removed by the charge eliminating device 35Y. The lubricating material removing device 50Y removes the powdery lubricating material 42Y, and the charging device 90Y removes the next material. It is subjected to charging.

  Similarly, toner images of the respective colors are formed on the other photosensitive drums 20M, 20C, and 20BK, and the formed toner images of the respective colors are transferred to the A1 direction by the primary transfer rollers 12M, 12C, and 12BK. 11 is sequentially transferred to the same position on the head. As the transfer belt 11 rotates in the A1 direction, the toner image superimposed on the transfer belt 11 moves to the secondary transfer nip, which is the position facing the secondary transfer roller 5, and is in close contact with the transfer sheet S. Secondary transfer is performed on the transfer paper S by the action of the next transfer bias and the nip pressure, and a full-color image is formed on the transfer paper S.

  The transfer sheet S conveyed between the transfer belt 11 and the secondary transfer roller 5 is fed from the sheet feeding device 61 by the feeding roller 3 and fed, and is detected by the registration roller pair 4 as a detection signal by the sensor. Based on this, the leading edge of the toner image on the transfer belt 11 is sent out at a timing facing the secondary transfer roller 5.

  When the toner image of all colors is transferred and carried on the transfer paper S, the transfer paper S enters the fixing device 6 and passes through the fixing portion between the heating roller 62 and the belt unit 63 due to the action of heat and pressure. The carried toner image is fixed, and the full color image is fixed on the transfer paper S. The fixed transfer paper S that has passed through the fixing device 6 passes through the paper discharge roller 7 and is stacked on the paper discharge tray 17 at the top of the main body 99. On the other hand, the surface of the transfer belt 11 after passing through the secondary transfer nip after the secondary transfer is cleaned by a cleaning brush and a cleaning blade provided in the cleaning device 13 to prepare for the next development process.

  The configuration of the photosensitive drum 20Y will be described in detail. Since the photosensitive drums 20M, 20C, and 20BK provided in the image forming units 60M, 60C, and 60BK have the same configuration, the description of the photosensitive drums 20M, 20C, and 20BK is omitted.

  As shown in FIG. 3, the photosensitive drum 20Y is formed on a conductive support 21Y as a base, a photosensitive layer 22Y as an organic photosensitive layer formed on the conductive support 21Y, and the photosensitive layer 22Y. And a flange (not shown) for supporting the photoconductor drum 20Y main body and transmitting rotation from the driving device.

  The photosensitive layer 22Y is a normal layer type provided with a charge generation layer 24Y located on the conductive support 21Y side and a charge transport layer 25Y formed on the charge generation layer 24Y.

  The photosensitive drum 20Y is widely known as an organic electrophotographic photosensitive member in which a photosensitive layer 22Y that is an organic photosensitive layer is provided on a conductive support 21Y that is a conductive substrate. The function dispersion type in which the generation layer 24Y and the charge transport layer 25Y are sequentially laminated is most preferable from the viewpoint of performance.

  As another configuration, a single layer type in which a charge generation material and a charge transport material are mixed, or a reverse layer type in which a charge generation layer is provided on a charge transport layer can be adopted. Further, instead of the photosensitive drum 20Y, the conductive support 21Y may be a belt-shaped image carrier.

  The protective layer 23Y is provided on the outermost surface of the photosensitive drum 20Y in order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning properties, etc. of the photosensitive drum 20Y. It is the outermost layer and constitutes the surface layer. The protective layer 23Y can be omitted, and in this case, the charge transport layer 25Y becomes the outermost layer and constitutes the surface layer.

  An undercoat layer may be provided between the photosensitive layer 22Y and the conductive support 21Y as necessary in order to improve adhesion and charge blocking properties. The undercoat layer may be a single layer or a plurality of layers.

  Hereinafter, the conductive support 21Y, the charge generation layer 24Y, the charge transport layer 25Y, and the protective layer 23Y will be described in more detail.

Conductive support 21Y The drum-like or belt-like conductive support 21Y includes a metal or an alloy such as Al, Ni, Fe, Cu, or Au; an insulating property such as plastic such as polyester, polycarbonate, or polyimide, or glass. Examples thereof include a substrate provided with a metal film such as Al, Ag, Au, or a metal oxide film such as In ₂ O ₃ or SnO ₂ .

-Regarding the charge generation layer 24Y The charge generation layer 24Y may be formed of only the charge generation material, or the charge generation material may be formed by being uniformly dispersed in a binder such as a binder resin. The charge generation layer 24Y is formed by dispersing these components in a suitable solvent, coating the conductive support 21Y on the conductive support 21Y, and drying.
The average film thickness of the charge generation layer 24Y is 0.01 to 2 μm, preferably 0.1 to 1 μm.

  Examples of the charge generating material include CIP Pigment Blue 25 (Color Index (CI) 21180), CIG Pigment Red 52 (CI45100), CII Basic Red 3 (CI45210), etc., phthalocyanine pigment having a porphyrin skeleton, and carbazole skeleton. An azo pigment having a stilbene skeleton (described in JP-A-53-138229), an azo pigment having a distyrylbenzene skeleton (described in JP-A-53-95033) 133455), azo pigments having a triphenylamine skeleton (described in JP-A-53-132547), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728), oxadi An azo pigment having an azole skeleton ( No. 54-12742), an azo pigment having a fluorenone skeleton (described in JP-A No. 54-22834), an azo pigment having a bis-stilbene skeleton (described in JP-A No. 54-17733), An azo pigment having a distyryl oxadiazole skeleton (described in JP-A No. 54-2129), an azo pigment having a distyryl carbazole skeleton (described in JP-A No. 54-17734), and a trisazo pigment having a carbazole skeleton (Described in JP-A-57-195767 and 57-195758), and the like, phthalocyanine pigments such as CI Pigment Blue 16 (CI74100), indigo pigments such as CI Eyebat Brown 5 (CI173410), Argos Car Red B (Violet Inc.) Indence Lens Carre Perylene pigments such as R (manufactured by Bayer), an organic pigment such as squaric pigment can be used.

  As the binder resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like are used.

  The amount of the binder resin is 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the charge generating material.

  Solvents used here are single solvents or mixed solvents such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, cyclohexane, methyl ethyl ketone, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, dichloromethane, and ethyl cellosolve. Is preferred.

Charge transport layer 25Y The charge transport layer 25Y is formed by dissolving a charge transport material, a binder resin and, if necessary, a plasticizer and a leveling agent in an appropriate solvent, and applying the solution onto the charge generation layer 24Y and drying it. The
The film thickness of the charge transport layer 25Y is 10 to 100 μm, preferably 20 to 40 μm.

  Examples of charge transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, imidazole derivatives, Electron donating properties such as triphenylamine derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-stilbene derivatives Substances.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinyl chloride, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin And thermoplastic or thermosetting resins such as urethane resin, phenol resin, and alkyd resin.

  Solvents for forming the charge transport layer 25Y include tetrahydrofuran, dioxane, toluene, monochlorobenzene, 1,2-dichloroethane, cyclohexanone, dichloromethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane. And a mixed solvent thereof is desirable.

-About the protective layer 23Y In the protective layer 23Y, as an inorganic filler which is a filler for improving the mechanical strength of the protective layer 23Y, improving wear resistance, and improving the lubricant coating property, a metal or a metal oxide The fine particles 26Y are contained in a dispersed manner. If the protective layer 23Y is omitted and the charge transport layer 25Y constitutes a surface layer, the fine particles 26Y are dispersed in the charge transport layer 25Y.

As the fine particles 26Y contained in the protective layer 23Y, either an organic filler or an inorganic filler may be used, but an inorganic filler is particularly preferably used.
Examples of the organic filler material include fluorine resin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like.

  Inorganic filler materials include metals such as silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconium oxide, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony-doped tin oxide, and tin-doped indium oxide. Examples thereof include oxides, metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride, potassium titanate, and boron nitride. These fillers may be used alone or in combination of two or more. That is, at least one kind of orientation filler may be used. In order to improve the dispersibility, these fine particles 26Y may be subjected to a surface treatment with a surface treatment agent.

  These fine particles 26Y can be used by being dispersed in the surface layer coating solution by a known means such as a ball mill or a sand mill. The content of the fine particles 26Y is preferably 5 to 40% by weight, more preferably 10 to 30%, based on the total solid content. The volume average particle diameter of the filler is 0.05 to 1.0 μm, more preferably 0.1 to 0.4 μm.

  In the experiments by the inventors, the photoconductor containing the filler in the surface layer in this manner has a wear amount of 3 to 10 times as long as it is used repeatedly in the copying process as compared with the conventional photoconductor not containing the filler. It has a configuration that can significantly improve the wear resistance.

  Furthermore, it has been confirmed that the change in the surface roughness due to the inclusion of the filler is also advantageous for the applicability of the lubricating material. There is also an advantage that a small amount is sufficient as compared with the case where no filler is contained.

  That is, in this embodiment, since the protective layer 23Y contains the fine particles 26Y, the blade 46Y does not adhere due to the unevenness of the surface of the photoreceptor drum 20Y, and therefore a gap is easily generated between the blade 46Y and the surface of the photoreceptor drum 20Y. The lubricating substance 42Y can be present in a more appropriate amount and uniformly, which is preferable.

  This is because when the protective layer 23Y contains the fine particles 26Y, irregularities are formed on the surface of the photoreceptor drum 20Y, and when the lubricating material 42Y is stretched by the blade 46Y, the particles of the lubricating material 42Y are absorbed by the fine particles 26Y. This is because the lubricant 42Y is easily held by the photosensitive drum 20Y because it is trapped in the groove formed on the surface of the photosensitive drum 20Y.

  In order to maintain such surface roughness over time, in this embodiment, it is more preferable to use a crosslinkable resin cured by heating or light energy irradiation as the resin constituting the protective layer 23Y as the surface layer. Although it is possible to use a crosslinkable resin for the charge transport layer such as the charge transport layer 25Y as a surface layer, there are many materials whose electrostatic characteristics deteriorate when the film is thickened. As in this embodiment, the surface layer is often used as a protective layer such as the protective layer 23Y, and a crosslinkable resin is often used for this.

  By using a crosslinkable resin as the resin contained in the protective layer 23Y, the mechanical deterioration of the photosensitive drum 20Y is small even when used repeatedly for a long time, and the scratch resistance of the surface of the photosensitive drum 20Y is significantly improved. The surface roughness can be maintained over a longer period.

  However, in order to satisfy the electrostatic characteristics of the photosensitive drum 20Y, it is necessary to provide a charge transport function to the protective layer 23Y which is the surface layer. This is because if the charge transport function is not provided, the residual potential is increased and the sensitivity is deteriorated, and the image quality stability of the photosensitive drum 20Y is greatly reduced. Therefore, the protective layer 23Y is capable of stabilizing electrostatic characteristics and other functions and effects by curing a radically polymerizable monomer having no charge transporting structure and a radically polymerizable compound having a charge transporting structure. Can be obtained sufficiently.

  By the way, when a low molecular charge transport material having no functional group is contained in the protective layer 23Y, precipitation of the low molecular charge transport material and white turbidity occur due to its low compatibility, and the mechanical properties of the protective layer 23Y are increased. The occurrence of image defects or the like is caused by a decrease in strength, a residual potential increase, sensitivity deterioration, and a significant increase in surface roughness. Therefore, in order to give the protective layer 23Y a charge transport function, it is preferable to use a radical polymerizable compound having a charge transport function and a functional group and to cure the radical polymerizable monomer.

  As the radical polymerizable compound having a charge transporting structure, a bifunctional or higher functional compound can be used as long as the smoothness, electrostatic characteristics, or durability of the surface of the photoreceptor drum 20Y is not impaired. However, when a radically polymerizable compound having a bi- or higher functional charge transporting structure is contained, the cross-linking density can be increased. However, since the bulky hole transporting compound is entangled with a large number of bonds, the protective layer 23Y is distorted. The resulting curing reaction is non-uniform. For this reason, the recovery force with respect to an external stress falls locally, and the variation in wear resistance becomes large.

  Therefore, it is preferable to use a radical polymerizable compound having a monofunctional charge transport structure rather than a radical polymerizable compound having a bifunctional or higher functional charge transport structure.

  As the radically polymerizable monomer having no charge transporting structure that is cured with such a radically polymerizable compound having a charge transporting function, a monofunctional and bifunctional radically polymerizable monomer may be used. In some cases, the cross-linking bond in 23Y is dilute and a dramatic improvement in scratch resistance may not be achieved.

  Therefore, in the photosensitive drum 20Y, it is more preferable to use a tri- or higher functional radical polymerizable monomer for the protective layer 23Y, thereby developing a three-dimensional network structure and increasing the degree of crosslinking and the elastic displacement rate. It becomes easy to achieve both the elastic displacement rate and the hardness.

  Thus, by curing using a polyfunctional radically polymerizable monomer, not only the mechanical wear resistance of the photoreceptor drum 20Y but also the scratch resistance can be remarkably improved. Effective and useful in maintaining roughness.

  Therefore, the protective layer 23Y uses a resin obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is done.

  Next, constituent materials of a tri- or higher functional radical polymerizable monomer having no charge transporting structure and a radical polymerizable compound having a monofunctional charge transporting structure will be described.

  A trifunctional or higher functional radical polymerizable monomer having no charge transporting property has a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, etc., such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. A monomer that does not have an electron transport structure such as an electron-withdrawing aromatic ring and has three or more radically polymerizable functional groups. The radical polymerizable functional group may be any group having a carbon-carbon double bond and capable of radical polymerization.

  Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) Examples of the 1-substituted ethylene functional group include functional groups represented by the following formulas.

In the formula, X1 is a single bond, an arylene group such as a phenylene group optionally having a substituent, a naphthylene group, an alkenylene group optionally having a substituent, a —CO— group, —COO—. Group, -CON (R10) -group (R10 represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group. Or -S- group.

  Specific examples of the 1-substituted ethylene functional group include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamino group, and a vinylthioether group.

(2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formulas.

  However, in the formula, Y is an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group such as a phenyl group which may have a substituent, or a naphthyl group. An alkoxy group such as a halogen atom, a cyano group, a nitro group, a methoxy group or an ethoxy group, a -COOR11 group (R11 is a hydrogen atom, an alkyl group such as an optionally substituted methyl group or an ethyl group, a substituted group; An aralkyl group such as benzyl or phenethyl group which may have a group, an aryl group such as phenyl group or naphthyl group which may have a substituent, or -CONR12R13 (R12 and R13 are a hydrogen atom, a substituent Aralkyl such as methyl group and ethyl group which may have a group, benzyl group, naphthylmethyl group and phenethyl group which may have a substituent Or an aryl group such as a phenyl group or a naphthyl group which may have a substituent, which may be the same or different from each other.), And X2 is the same group as X1 in the above formula 1; The bond represents an alkylene group which may have the same substituent as X1. However, at least one of Y and X2 is an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring.

  Specific examples of 1,1-substituted ethylene functional groups include α-acryloyloxy chloride, methacryloyloxy, α-cyanoethylene, α-cyanoacryloyloxy, α-cyanophenylene, and methacryloylamino groups. Can be mentioned.

  Examples of the substituent further substituted on the substituents for X1, X2, and Y include, for example, alkyl groups such as halogen atoms, nitro groups, cyano groups, methyl groups, and ethyl groups, and alkoxy groups such as methoxy groups and ethoxy groups. Group, aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group, and the like.

  Among these radically polymerizable functional groups, an acryloyloxy group and a methacryloyloxy group are particularly useful, and it is desirable to include any one or a combination thereof. A compound having three or more acryloyloxy groups is obtained by, for example, using a compound having three or more hydroxyl groups in the molecule, acrylic acid (salt), acrylic acid halide, or acrylic ester, and performing an ester reaction or a transesterification reaction. Obtainable. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

  Examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.

  Examples of such radical polymerizable monomers include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, alkylene-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, and caprolactone. Modified trimethylolpropane triacrylate, alkylene modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH (epichlorohydrin) modified glycerol triacrylate, EO modified glycerol triacrylate, PO-modified glycerol triacrylate, Lith (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl Modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO modified phosphoric acid triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, etc. These may be used alone or in combination of two or more.

  The trifunctional or higher functional radical polymerizable monomer having no charge transporting structure has a functional group ratio, that is, a value obtained by dividing the molecular weight by the number of functional groups in order to form a dense cross-linked bond in the protective layer 23Y. Is desirable. That is, the ratio of the molecular weight to the number of functional groups in the radical polymerizable monomer is desirably 250 or less. As a result, the elastic displacement rate and hardness of the protective layer 23Y are improved, and the scratch resistance of the surface of the photoreceptor drum 20Y tends to increase.

  The proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used for the protective layer 23Y is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the protective layer 23Y. It substantially depends on the proportion of the tri- or higher functional radical polymerizable monomer in the solid content of the coating liquid. If the monomer component is less than 20% by weight, the three-dimensional cross-linking density of the protective layer 23Y is small, and a dramatic improvement in scratch resistance may not be achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrostatic characteristics are deteriorated, particularly the residual potential is increased and the sensitivity is deteriorated. Since the required wear resistance and electrostatic characteristics differ depending on the process used, it cannot be said unconditionally, but the range of 30 to 70% by weight is most preferable in consideration of the balance of both characteristics.

  A radically polymerizable compound having a monofunctional charge transporting structure is, for example, a hole transporting structure such as triarylamine, hydrazone, pyrazoline, or carbazole, such as an electron having a condensed polycyclic quinone, diphenoquinone, a cyano group, or a nitro group. It refers to a compound having an electron transport structure such as an attractive aromatic ring and having one radical polymerizable functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful.

  A triarylamine structure is effective as a charge transporting structure, and in particular, when a compound represented by one or more of the following general formulas (1) or (2) is used, electrostatic characteristics such as sensitivity and residual potential Is well maintained.

  In the formula, R1 is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a cyano group, a nitro group, an alkoxy group, -COOR7 (R7 is hydrogen Atom, substituted or unsubstituted alkyl group, substituted or unsubstituted aralkyl group, or substituted or unsubstituted aryl group), halogenated carbonyl group or CONR8R9 (R8 and R9 are hydrogen atoms, halogen atoms, substituted or unsubstituted) Represents an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, which may be the same or different from each other, and Ar1 and Ar2 represent a substituted or unsubstituted arylene group. , May be the same or different. Ar3 and Ar4 represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted aralkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3.

  Specific examples of the compounds represented by the general formulas (1) and (2) are shown below.

  In the general formulas (1) and (2), in the substituent of R1, as the alkyl group, for example, methyl group, ethyl group, propyl group, butyl group, etc., as the aryl group, phenyl group, naphthyl group, etc. are aralkyl. Examples of the group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include a halogen atom, a nitro group, a cyano group, a methyl group, and an ethyl group. An alkyl group such as a group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, or the like Good.

  Of the substituents for R1, particularly preferred are a hydrogen atom and a methyl group. Substituted or unsubstituted Ar3 and Ar4 are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-condensed cyclic hydrocarbon groups, and heterocyclic groups.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

  Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.

  Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

  The aryl group represented by Ar3 and Ar4 may have a substituent as shown below, for example.

(1) Halogen atom, cyano group, nitro group and the like.

(2) Alkyl groups, preferably C1-C12, especially C1-C8, more preferably C1-C4 linear or branched alkyl groups, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, It may have a phenyl group substituted with a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxy group. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

(3) An alkoxy group (-OR2), wherein R2 represents the alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.

(4) An aryloxy group, and examples of the aryl group include a phenyl group and a naphthyl group. These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.

(5) Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.

(6) is a group represented by the following formula:

  In the formula, R3 and R4 each independently represent a hydrogen atom, an alkyl group defined in the above (2), or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group, and these may contain a C1 to C4 alkoxy group, a C1 to C4 alkyl group, or a halogen atom as a substituent. R3 and R4 may jointly form a ring.

  Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.

(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

  The arylene group represented by Ar1 and Ar2 is a divalent group derived from the aryl group represented by Ar3 or Ar4.

  X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.

The substituted or unsubstituted alkylene group is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom, a hydroxyl group, It may have a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

  The substituted or unsubstituted cycloalkylene group is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

  The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, alkylene ether group alkylene group is hydroxyl group, methyl group, ethyl group, etc. You may have the substituent of.

  The vinylene group is

R5 is hydrogen, an alkyl group (same as the alkyl group defined in (2)), an aryl group (same as the aryl group represented by Ar3 or Ar4), a is 1 or 2, and b is 1-3.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted aralkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether group include the alkylene ether group represented by X.
Examples of the alkyleneoxycarbonyl group include a caprolactone-modified group.

  The radically polymerizable compound having a monofunctional charge transporting structure of the present invention is more preferably at least one compound having the structure of the following general formula (3).

  In the formula, each of o, p, and q is an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. The cases may be the same or different. s and t represent an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

Represents.

  As the compound represented by the above general formula, a compound having a methyl group or an ethyl group as a substituent for Rb and Rc is particularly preferable.

  The radical polymerizable compound having a monofunctional charge transporting structure represented by the above general formulas (1) and (2), particularly (3) used in the present invention has a carbon-carbon double bond open on both sides. In the polymer that is incorporated into the chain polymer and cross-linked by polymerization with a tri- or higher functional polymerizable monomer, it does not form a terminal structure and exists in the main chain of the polymer. And present in a cross-linked chain between the main chain and the main chain (this cross-linked chain includes an intermolecular cross-linked chain between one polymer and another polymer, and a main chain folded in one polymer. There is an intramolecular cross-linked chain that crosslinks a part of the main chain and another part derived from the polymerized monomer at a position distant from this in the main chain). Triarylamine structures that hang from the chain portion even when present in the chain , Having at least three aryl groups arranged radially from the nitrogen atom and being bulky, but not directly bonded to the chain part and suspended from the chain part via a carbonyl group, etc. Since these triarylamine structures can be arranged adjacent to each other in the polymer, the structural distortion in the molecule is small, and the electrophotographic sensitivity is low. In the case of the body surface layer, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.

  Specific examples of the radical polymerizable compound having a monofunctional charge transport structure are shown below. However, it is not limited to compounds having these structures.

  The radically polymerizable compound having a monofunctional charge transport structure is important for imparting the charge transport performance of the protective layer 23Y, and this component is 20 to 80% by weight, preferably 30 to 70%, based on the total amount of the protective layer 23Y. % By weight. If this component is less than 20% by weight, the charge transporting performance of the protective layer 23Y cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appear with repeated use. On the other hand, when the content exceeds 80% by weight, the content of the trifunctional monomer having no charge transporting structure is lowered, and the crosslinking density is lowered, so that high wear resistance is not exhibited. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but the range of 30 to 70% by weight is most preferable in consideration of the balance of both characteristics.

  As the resin contained in the protective layer 23Y, a resin obtained by curing at least a trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure is more preferable. Of course, monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers can also be used or used together. Known radical polymerizable monomers and oligomers can be used.

  When the curable resin is used for the protective layer 23Y layer, a polymerization initiator may be used in the surface layer in order to efficiently advance the crosslinking reaction as necessary.

  The protective layer 23Y can contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement), a leveling agent, and a low molecular charge transport material having no radical reactivity, as necessary. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20% by weight or less, preferably 10% by weight or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3% by weight or less is appropriate. When these addition amounts are increased more than necessary, curing may be inhibited, the film may be deposited on the surface, or the coating film may become clouded, which greatly affects the scratch resistance and wear resistance of the photoreceptor drum 20Y. There is a fear that it is necessary to keep the minimum amount.

The image forming apparatus 100 is configured as described above.
Here, in general, among various devices such as the cleaning device 70Y, the developing device 80Y, and the charging device 90Y included in the process cartridge such as the process cartridge 68Y, the life of the image carrier such as the photosensitive drum 20Y is the shortest. The replacement frequency of the process cartridge is determined by the life of the image carrier.

  Since the process cartridge 68Y is replaced as a unit, the component life around the photosensitive drum 20Y is adjusted by adjusting the amount of the lubricating substance 42Y provided in the lubricating substance supply device 40Y and the initial film pressure of the protective layer 23Y. At the same time, the life of the photosensitive drum 20Y is increased, and the replacement frequency of the process cartridge 68Y is suppressed. Thus, other devices that have been exchanged together with the image carrier before the end of their lifetime, such as the lubricating substance supply device 40Y, the cleaning device 70Y, the developing device 80Y, and the charging device 90Y in this embodiment, can be used. The apparatus can be used effectively and user convenience can be improved.

  Due to the agent application effect of the lubricating substance 42Y, it may be possible that the life of the cleaning cartridge 78Y and the charging roller 91Y is much longer than the parts in the process cartridge 68Y. In this case, the process cartridge 68Y is not configured. It is possible to replace each part to reduce the replacement frequency of the expensive photoconductor drum 20Y as much as possible, or to use the photoconductor with higher durability until the lifetime of the machine.

  Further, by attaching the lubricating substance 42Y to the surface of the photoconductor drum 20Y, the mechanical adhesion between the surface of the photoconductor drum 20Y and the toner is weakened. As a result, the transfer efficiency can be improved, and the image quality can be improved. The effect of improvement and reduction of transfer residual toner is also obtained.

[Modification]
A modification of the image forming apparatus 100 will be described with reference to FIG. In this modified example, differences from the above-described image forming unit and process cartridge are mainly described, and the same portions are denoted by the same reference numerals and description thereof is omitted as appropriate. Similarly to the description of the above embodiment, the image forming unit 60Y for forming a yellow toner image and the process cartridge 68Y will be described as representative image forming units for forming toner images of respective colors. FIG. 6 corresponds to FIG. 3 and is an enlarged view showing a schematic configuration of an image forming unit 60Y in the present modification.

  In the present modification, the lubricating substance supply device 40Y is disposed on the downstream side of the static eliminating device 35Y and on the upstream side of the lubricating substance removing device 50Y in the rotation direction B1 of the photosensitive drum 20Y. This is different from the above-described embodiment in that it has a blade 46Y as a lubricating material application blade that is fixedly supported by the case 41Y shown in FIG. 2 and whose tip is in contact with the photosensitive drum 20Y. Except for this, the configuration is the same as that of the above-described embodiment.

  By disposing the lubricating substance supply device 40Y at such a position, the lubricating substance supply device 40Y is arranged on the downstream side of the cleaning device 70Y in the rotation direction B1 of the photosensitive drum 20Y. The transfer residual toner is prevented or suppressed from entering the device 40Y.

  Therefore, the amount of transfer residual toner adhering to the brush roller 47Y is reduced. Here, it is known that when the transfer residual toner adheres to the brush roller 47Y, the amount of the brush roller 47Y scraping off the solid lubricant 42Y greatly increases. However, even if the amount of residual toner changes due to a change in the image area ratio, in other words, a change in the amount of toner adhering to the photosensitive drum 20Y during image formation, the supply amount of the lubricating substance 42Y. Is suppressed from being influenced by the amount of residual toner transferred to the cleaning device 70Y, the lubricating material 42Y is stably supplied onto the photosensitive drum 20Y, and the consumption of the lubricating material 42Y is suppressed. Is done.

  In addition, since the blade 46Y is provided, the lubricating material 42Y applied to the photosensitive drum 20Y by the brush roller 47Y is stretched by the blade 46Y, and the lubricating material 42Y is formed into a film. A film is formed efficiently. Therefore, in this configuration, the amount of the powdery lubricating substance 42Y reaching the lubricating substance removing device 50Y is larger than that in the structure in which the film of the lubricating substance 42Y is formed by the cleaning blade 78Y whose main purpose is cleaning of the transfer residual toner. Therefore, the consumption amount of the lubricating substance 42Y is reduced. In addition, the lubricating substance removing device 50Y is less contaminated, and the performance of the lubricating substance removing device 50Y is maintained over a long period of time.

  The blade 46Y is in contact with the photosensitive drum 20Y by the trailing method, but may be in contact with the photosensitive drum 20Y by the counter method. Further, the blade 46Y is not provided as a part of the configuration of the lubricating substance supply device 40Y, but may be provided as a configuration outside the lubricating substance supply device 40Y. In addition, the blade 46Y may be omitted if the lubricating material 42Y is satisfactorily applied to the photosensitive drum 20Y by the cleaning blade 78.

〔Example〕
EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited only to these Examples. In the following text, “parts” represents parts by weight.

Example 1
(Production of photoconductor)
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and an 18 μm charge transport layer were formed to prepare a photoreceptor.

[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts ・ Methyl ethyl ketone 50 parts

[Coating liquid for charge generation layer]
-Bisazo pigment of the following structural formula (I) 2.5 parts-Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part-Cyclohexanone 200 parts-Methyl ethyl ketone 80 parts

[Coating liquid for charge transport layer]
・ 10 parts of bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals)
・ Low molecular charge transport material (D-1) of the following structural formula (II) 7 parts ・ Tetrahydrofuran 100 parts ・ Tetrahydrofuran solution of 1% silicone oil 1 part (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Evaluation methods)
The evaluation device used was a modified black station of a Ricoh printer Ipsio color 8150. As the charging member, a hard resin roller having a diameter of 10 mm was used, and the gap with the photosensitive member was adjusted to 50 μm. As an electrification condition, an alternating electric field in which a sine wave of Vpp = 3 kV and frequency = 1.5 kHz was superimposed as an AC component on a DC component of −600 V was applied. Further, a zinc stearate bar as a lubricant was brought into contact with the cleaning brush at a pressure of 1500 mN, and zinc stearate was supplied onto the photosensitive member via the brush.

  Further, following the configuration shown in FIG. 1 and the like, a hard resin roller having a diameter of 8 mm is used as a lubricant removing member between the zinc stearate application brush and the charging roller (downstream of the cleaning blade and upstream of the charging roller in the moving direction of the photosensitive member). (Position corresponding to). The lubricant removing roller is not in contact with the photoreceptor, and is rotated at the same speed as the photoreceptor. The gap with the photoconductor was 50 μm, and a DC voltage of +500 V was applied.

  Using this modified evaluation machine, the photoconductor produced as described above was mounted and 50,000 sheets were run. If black streaks appear on the image during running, count the number of sheets until the black streaks occur, and measure the photoconductor wear and lubricant consumption after evaluation for those with no black streaks up to 50,000. It was decided to. The results are shown in Table 2.

Example 2
In Example 1, a photoconductor was prepared and evaluated in the same manner as in Example 1 except that 5 parts of silicone resin fine particles (Tospearl 120, manufactured by GE Toshiba Silicone) were added as a filler to the charge transport layer coating solution.

Example 3
A photoconductor was prepared and evaluated in the same manner as in Example 2 except that alumina fine particles (AA03: manufactured by Sumitomo Chemical Co., Ltd.) were used as fillers added to the charge transport layer coating liquid in Example 2 instead of silicone resin fine particles. did.

Example 4
In the same manner as in Example 1, an undercoat layer, a charge generation layer, and a charge transport layer were applied.
On this charge transport layer, a coating solution for a protective layer having the following composition is spray-coated, and a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 200 mW / cm ² , irradiation time: 20 seconds. The photosensitive member was prepared by irradiating with light and further drying at 130 ° C. for 20 minutes to provide a protective layer of 4 μm.

[Coating liquid for protective layer]
-Radical polymerizable monomer having no charge transporting structure 10 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku)
Molecular weight: 1947, number of functional groups: 6 functions, molecular weight / number of functional groups = 325
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
-Photopolymerization initiator 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
・ Tetrahydrofuran 100 parts ・ Silicone resin fine particles 5 parts (Tospearl 120, manufactured by GE Toshiba Silicone)

Example 5
A photoconductor was produced and evaluated in the same manner as in Example 3 except that the protective layer coating solution of Example 4 had the following constitution.

[Coating liquid for protective layer]
-Radical polymerizable monomer having no charge transport structure 10 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-60, manufactured by Nippon Kayaku)
Molecular weight: 1263, number of functional groups: 6 functions, molecular weight / number of functional groups = 211
10 parts of radically polymerizable compound having a charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 2 parts 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
・ Alumina fine particles (AA03: manufactured by Sumitomo Chemical Co., Ltd.) 5 parts ・ Tetrahydrofuran 88 parts

Example 6
As the radical polymerizable compound having a charge transporting structure in the protective layer coating solution of Example 5, Exemplified Compound No. 1 was used. An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that No. 1 was used.

Comparative example 1
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the lubricant removing roller was not installed in the evaluation machine.

Comparative example 2
In Example 2, the evaluation was performed in the same manner as in Example 1 except that the lubricant removing roller was not installed in the evaluation machine.

Comparative example 3
In Example 6, the evaluation was performed in the same manner as in Example 1 except that the lubricant removing roller was not installed in the evaluation machine.

  Table 2 shows the results of Examples 1 to 6 and Comparative Examples 1 to 3.

  From this result, the effect of providing a lubricant removing means, the effect of containing a filler in the surface layer, the effect of the filler being an inorganic filler, the effect of using the surface layer as a protective layer, forming a protective layer It was confirmed that the ratio of the molecular weight to the number of functional groups in the radical polymerizable monomer having three or more functional groups having no charge transporting structure is 250 or less.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.
For example, in the above embodiment, a two-component developer is used, but the developer may be a one-component developer.

  The process cartridge includes at least an image carrier, a charging unit, a lubricant applying unit, and a lubricant removing unit, and may be detachable from the main body of the image forming apparatus. The selection of the other components is appropriately performed in consideration of the image carrier, the life and cost of the components, the ease of construction of the process cartridge, and the like.

  Further, in the above embodiment, the lubricant is solid, but the lubricant may be powder. In this case, the lubricant is accommodated in the case, and an agitator or the like having a rotating blade member or the like is provided instead of the brush roller or the spring as the lubricant supply member, and the image is carried by the agitator. It can be configured to supply and apply a lubricant to the body. Such a configuration can be increased in size because the density of the lubricant is lower than when a solid lubricant is used, but has the advantage that the particle size of the lubricant supplied to the image carrier is uniform.

  In addition, the image forming apparatus 100 is not a so-called tandem type image forming apparatus, and so-called one drum that forms toner images of respective colors sequentially on one photosensitive drum and sequentially superimposes the color toner images to obtain a color image. The present invention can be similarly applied to a type image forming apparatus. Further, the present invention can be applied not only to a color image forming apparatus but also to a monochrome image forming apparatus. In any type of image forming apparatus, the toner image of each color may be directly transferred onto a transfer sheet or the like without using an intermediate transfer member. In this case, for example, referring to FIG. 3, the transfer belt 11 corresponds to the transfer sheet S.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic front view showing a configuration around one image carrier among a plurality of image carriers provided in the image forming apparatus shown in FIG. 1. FIG. 3 is a schematic diagram illustrating a configuration around an image carrier illustrated in FIG. 2. FIG. 4 is a schematic side view showing a part of the configuration of the developing unit or the lubricant removing unit shown in FIG. 2 or FIG. 3. FIG. 2 is an enlarged sectional view of a surface structure of an image carrier provided in the image forming apparatus shown in FIG. 1. FIG. 4 is a schematic diagram showing a modification of the configuration around the image carrier shown in FIG. 3. FIG. 10 is a correlation diagram showing changes in the amount of abrasion on the surface of an image carrier due to charging in a conventional image forming apparatus. FIG. 5 is a prediction diagram schematically showing how the surface of an image carrier is scraped by charging.

Explanation of symbols

20Y, 20M, 20C, 20BK Image carrier 23Y, 23M, 23C, 23BK Surface layer 26Y, 26M, 26C, 26BK Filler, inorganic filler 40Y, 40M, 40C, 40BK Lubricant coating means 42Y, 42M, 42C, 42BK Lubricant , Fatty acid metal salt, zinc stearate 50Y, 50M, 50C, 50BK Lubricant removing means 51Y, 51M, 51C, 51BK Lubricant removing member 68Y, 68M, 68C, 68BK Process cartridge 90Y, 90M, 90C, 90BK Charging means 100 Images Forming equipment

Claims (18)

  An image carrier, a charging means for charging the image carrier, a lubricant application means for applying a lubricant to the image carrier, a downstream side of the lubricant application means in the moving direction of the image carrier, and the An image forming apparatus comprising: a lubricant removing unit that is located upstream of the charging unit and removes the powdery lubricant on the image carrier. The image forming apparatus according to claim 1.
The image forming apparatus characterized in that the lubricant removing means includes a lubricant removing member that is disposed in non-contact with the image carrier and electrostatically removes the powdery lubricant on the image carrier. apparatus. The image forming apparatus according to claim 2.
The image forming apparatus according to claim 1, wherein the lubricant removing member has a rotatable roller shape. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the lubricant is a fatty acid metal salt. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the fatty acid metal salt is zinc stearate. The image forming apparatus according to any one of claims 1 to 5,
An image forming apparatus, wherein the surface layer of the image carrier contains a filler. The image forming apparatus according to claim 6.
The image forming apparatus, wherein the filler is at least one inorganic filler. The image forming apparatus according to any one of claims 1 to 7,
An image forming apparatus, wherein the surface layer of the image carrier comprises a crosslinked layer obtained by curing at least a radically polymerizable monomer having no charge transporting structure and a radically polymerizable compound having a charge transporting structure. The image forming apparatus according to claim 8.
An image forming apparatus, wherein the radical polymerizable monomer is trifunctional or more and the radical polymerizable compound is monofunctional. The image forming apparatus according to claim 9.
The image forming apparatus, wherein the radical polymerizable compound is one or more of the following general formula (1) or (2).

(Wherein R1 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a cyano group, a nitro group, an alkoxy group, -COOR7 (R7 represents A hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), a halogenated carbonyl group, or CONR8R9 (R8 and R9 are hydrogen atoms, halogen atoms, substituted or unsubstituted) An alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, which may be the same or different from each other, and Ar1 and Ar2 represent a substituted or unsubstituted arylene group. Ar3 and Ar4 may be substituted or unsubstituted. X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted aralkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group, and m and n are 0-3. Represents an integer.) The image forming apparatus according to claim 9 or 10, wherein:
The image forming apparatus, wherein the radical polymerizable compound is at least one of compounds represented by the following general formula (3).

(In the formula, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent substituents other than a hydrogen atom and represent an alkyl group having 1 to 6 carbon atoms, and are the same. S and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

Represents. ) 12. The image forming apparatus according to claim 8, wherein
An image forming apparatus, wherein the functional group of the radical polymerizable compound is an acryloyloxy group or a methacryloyloxy group. The image forming apparatus according to any one of claims 8 to 12,
The image forming apparatus, wherein the charge transporting structure of the radical polymerizable compound is a triarylamine structure. The image forming apparatus according to claim 9.
The image forming apparatus, wherein the ratio of the molecular weight to the number of functional groups in the radical polymerizable monomer is 250 or less. The image forming apparatus according to any one of claims 8 to 14,
An image forming apparatus, wherein the functional group of the radical polymerizable monomer is an acryloyloxy group and / or a methacryloyloxy group. The image forming apparatus according to any one of claims 1 to 15,
The charging method of the image carrier by the charging means is a contact method or a proximity method,
The image forming apparatus, wherein the charging unit performs AC charging in which an AC voltage is superimposed on a DC voltage. It is used for the image forming apparatus according to any one of claims 1 to 16,
A process cartridge including at least the image carrier, the charging unit, the lubricant applying unit, and the lubricant removing unit, and being detachable from the main body of the image forming apparatus. An image forming method for forming an image using the image forming apparatus according to claim 1 or the process cartridge according to claim 17.

Images