JP2016090618A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus that can suppress the occurrence of image streaks due to an instantaneous change in peripheral speed of a photoreceptor and/or an intermediate transfer body during a printing operation, and suppress the occurrence of image streaks that occurs in a high-temperature and high-humidity environment.SOLUTION: A cleaning blade included in cleaning means for a photoreceptor has a specific Young's modulus and a specific average rate of change of the Young's modulus according to a distance from the surface of a contact part with a photoreceptor, and the photoreceptor has a plurality of recessed parts having specific dimensions formed on its surface at a specific area ratio.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an electrophotographic apparatus.

  In general, in an electrophotographic apparatus, a series of electrophotographic image processes including charging, exposure, development, transfer, cleaning, and the like are sequentially performed on an electrophotographic photoreceptor (hereinafter also simply referred to as “photoreceptor”), whereby an image is obtained. Is output.

  In recent years, in order to support full-color printing, electrophotographic apparatuses using an intermediate transfer member as transfer means have been widely used. The full-color electrophotographic apparatus is a four-cycle system (in the case of four colors) in which developing means for each color are arranged around one photoconductor, and a plurality of photoconductors dedicated for each color in one electrophotographic apparatus. It is roughly divided into the tandem system installed. In the case of an electrophotographic apparatus equipped with an intermediate transfer member, a toner image of each color is sequentially laminated on the intermediate transfer member to form a full color image in any method. At this time, if each toner image is formed at a position different from the original location on the intermediate transfer member, a problem of color misregistration occurs. Also, during the printing operation, the photosensitive member and the intermediate transfer member each rotate at a predetermined peripheral speed, and the relative speed between them needs to be kept constant. Affects the image. Specifically, when the relative speed changes instantaneously, an image streak (hereinafter also referred to as a shock streak) may occur in a direction parallel to the generatrix direction of the photoreceptor. Some electrophotographic apparatuses using an intermediate transfer member are provided with a mechanism for suppressing problems such as color misregistration and shock stripes. Further, in the tandem electrophotographic apparatus, since it is necessary to take measures against these problems for each photoconductor, the degree of difficulty in designing the apparatus becomes higher.

  As one means for improving the shock stripe, a method of suppressing the occurrence of an instantaneous change in the relative speed between the photosensitive member and the intermediate transfer member is conceivable.

  One of the causes that the peripheral speed of the photosensitive member and / or the intermediate transfer member changes instantaneously is a sudden change in the frictional force acting between the photosensitive member and the intermediate transfer member. Compared to the case where no toner is present in the nip portion where the photosensitive member and the intermediate transfer member abut, and the toner is directly in contact with each other, the frictional force is relatively small when the toner is present in the nip portion. As an example, consider the case of printing an entire halftone image. In the stage before the leading end of the halftone image developed on the photoreceptor reaches the nip, there is no toner in the nip. On the other hand, after the leading edge of the halftone image reaches the nip, toner intervenes in the nip. For this reason, the frictional force suddenly decreases at the time when the leading edge of the halftone image reaches the nip portion, and the peripheral speeds of the photosensitive member and the intermediate transfer member may relatively instantaneously change. . When the rotational speed of the photosensitive member changes, the irradiation position of image exposure deviates from the correct position only at that moment, and white stripes or black stripes are generated on the image. In addition, when the rotational speed of the intermediate transfer member is changed in the tandem electrophotographic apparatus, the influence may extend to other color stations and cause image streaks.

  As a means of suppressing the occurrence of this change in relative speed itself, the friction force acting between the photosensitive member and the intermediate transfer member when they are in direct contact is reduced, and toner is interposed in the nip portion. It is conceivable to reduce the difference between the frictional force and the frictional force.

  As means for reducing the frictional force by the photosensitive member, a method of reducing the substantial contact area when contacting the cleaning member or the like by appropriately roughening the surface layer of the photosensitive member has been conventionally studied. Patent Document 1 discloses a technique for roughening the circumferential surface of a photoreceptor by blasting and reducing the frictional force with a cleaning blade.

  Further, in Patent Document 2, the density of 76 or more and 1000 or less of each independent concave portion having an average major axis diameter of an opening larger than 3.0 μm and 14.0 μm or less on the surface of the photoreceptor is 100 μm square. It is formed with. By doing so, a technique is disclosed in which good cleaning properties can be obtained and torque increase due to durability can be suppressed.

  Next, the cleaning means for the photoreceptor will be described. Cleaning is performed for the purpose of removing toner remaining on the surface of the photoreceptor (hereinafter referred to as transfer residual toner) after the transfer process. Various means are known as the means. For example, a method of scraping off transfer residual toner by bringing a cleaning blade made of a flat elastic body into contact with an electrophotographic photosensitive member is widely used because it is simple and effective.

  The cleaning blade is installed in the electrophotographic apparatus so as to maintain a contact angle and a contact pressure within a certain range with respect to the surface of the photoreceptor. The edge portion (tip ridge line portion) at the tip of the cleaning blade comes into contact with the surface of the photoreceptor. At the time of image output, the edge portion is rubbed by the surface of the photoreceptor, so that the cleaning blade material is also required to have wear resistance. Urethane rubber (urethane elastomer) can be suitably used as a material for a cleaning blade because of its excellent permanent set and wear resistance.

  However, in the case of a cleaning blade using a normal urethane rubber, in an electrophotographic apparatus using a toner whose toner particle shape is close to a spherical shape (spherical toner), the toner may pass through the cleaning blade and cause poor cleaning. there were. In addition, when using a blade made of urethane rubber having high resilience to improve the cleaning failure, vibration noise (blade squeal) may occur due to vibration of the edge portion of the cleaning blade. In addition, the frictional force between the cleaning blade and the surface of the photosensitive member may increase and the cleaning blade may be swollen (blade curling).

  As a method for solving these problems, Patent Document 3 discloses that layers of materials having different characteristics are laminated in the thickness direction of the cleaning blade, and the layer in contact with the member to be cleaned is made of a high hardness resin. A cleaning device is disclosed.

  Patent Document 4 describes a technique in which a surface layer having a hardness higher than that of the base layer of the cleaning blade is provided at a contact portion of the cleaning blade with the member to be cleaned.

  Patent Document 5 describes a technique in which fine particles having an average particle diameter of 3 μm or less are contained in a surface layer in contact with a member to be cleaned in a urethane rubber cleaning blade.

  Patent Document 6 describes a technique for continuously increasing the nitrogen concentration from the inside of the contact portion with the member to be cleaned in the cleaning blade toward the surface of the contact portion.

  Patent Document 7 describes a technique for making the concentration of isocyanurate groups on the surface of the edge portion of a cleaning blade made of urethane rubber (urethane elastomer) higher than the concentration of isocyanurate groups inside the edge portion. Yes.

JP-A-2-150850 JP 2007-233355 A JP 2004-184462 A JP 2012-150203 A JP 2008-268670 A JP 2009-025451 A JP 2001-075451

  However, as a result of the study by the present inventors, it has been found that the above-described conventional techniques have the following problems.

  First, the present inventors provide a plurality of independent concave portions on the surface of the photosensitive member based on the techniques disclosed in Patent Document 1 and Patent Document 2 to reduce the contact area with the intermediate transfer member. Therefore, we tried to reduce the frictional force between them. At this time, the concave portion had a depth of 0.5 μm or more and 3.0 μm or less, a longest opening diameter of 20 μm or more and 100 μm or less, and a shortest opening diameter of 20 μm or more and 100 μm or less. Further, in order to correspond to a region where the toner image can be developed, the ratio of the area occupied by the concave portion on the entire surface of the photosensitive member where the photosensitive member and the cleaning blade contact each other is set to 30% to 70%. The shock streak was improved by using a photoconductor having such a surface shape.

  However, when a photoconductor having such a surface shape and a conventional photoconductor cleaning blade are used in combination, there remains room for improvement. That is, when a halftone image having a density of about 30% is output after printing in a low print mode under a high temperature and high humidity environment, a streak-like image defect (hereinafter referred to as H / H initial streak) is generated on the halftone image. There was room for further improvement.

  Further, with respect to the cleaning blade, problems other than the H / H initial streak may occur. The stacked cleaning blades having a surface layer and a base layer as described in Patent Documents 3 to 5 have different behaviors between the surface layer and the base layer when in contact with the surface of the photoreceptor. For this reason, the followability to concave portions formed on the surface of the photosensitive member and foreign matters (including toner) existing on the surface becomes insufficient, and the surface layer may be peeled off or chipped (curled). there were.

  The technique described in Patent Document 6 is a technique for increasing the crosslink density on the surface side of the contact portion with the photoreceptor in a urethane rubber cleaning blade to form a hard segment. In some cases, the followability to the shape portion is insufficient. In the technique described in Patent Document 7, a mixed liquid in which an isocyanate compound and an isocyanurate-forming catalyst are mixed is applied to the inner surface of a mold to increase the concentration of isocyanurate groups on the surface of a cleaning blade made of urethane rubber. Technology. According to this technology, when the concentration of the isocyanurate group is increased to a level at which a substantially low hardness is achieved near the surface of the cleaning blade and a sufficiently low torque is achieved, In some cases, the followability to the foreign matter existing on the surface is lowered. When the followability to the concave portion formed on the surface of the photosensitive member or the foreign matter existing on the surface is lowered, toner slips easily.

  Further, in each of the above-described conventional techniques, when the cleaning blade sandwiches toner particles or particles as large as toner particles between the member to be cleaned, it is difficult to obtain sufficient followability to the toner particles. Specifically, the contact portion of the cleaning blade with the photosensitive member is deformed with a very large radius of curvature with respect to the sandwiched particles, so that toner may slip around the sandwiched particles.

  An object of the present invention is to provide an electrophotographic apparatus in which the frictional resistance between a photosensitive member and an intermediate transfer member is reduced and the occurrence of the shock stripe is suppressed. Another object of the present invention is to provide an electrophotographic apparatus in which the problem of H / H initial streak is improved by providing a photoconductor cleaning blade that has good followability to the photoconductor surface shape and is not easily chipped.

The present invention is an electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, an intermediate transfer member, a primary transfer unit, a secondary transfer unit, and a cleaning unit for an electrophotographic photosensitive member,
The electrophotographic photosensitive member has a cleaning blade made of urethane rubber, and the cleaning blade is brought into contact with the surface of the electrophotographic photosensitive member to clean the surface of the electrophotographic photosensitive member. Cleaning means,
In the cleaning blade, the Young's modulus (Y ₀ ) of the surface C of the contact portion with the electrophotographic photosensitive member is 10 mgf / μm ² or more and 400 mgf / μm ² or less,
The ratio (Y ₅₀ / Y ₀ ) between the Young's modulus (Y ₅₀ ) and the Young's modulus (Y ₀ ) at a position inside 50 μm from the surface C is 0.5 or less,
When the Young's modulus at a position inside 20 μm from the surface C is defined as (Y ₂₀ ), the average change rate of Young's modulus from the surface C to the position inside 20 μm [{(Y ₀ −Y ₂₀ ) / Y ₀ } / (20-0)] is equal to or greater than the average rate of change of Young's modulus from the position inside 20 μm to the position inside 50 μm [{(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20)]. Yes,
A plurality of concave portions are formed on the surface of the electrophotographic photosensitive member,
The ratio of the area occupied by the concave portion on the entire surface where the electrophotographic photosensitive member and the cleaning blade come into contact is 30% or more and 70% or less,
The concave portion is an electrophotographic apparatus having a depth of 0.5 μm to 3.0 μm, an opening longest diameter of 20 μm to 100 μm, and an opening shortest diameter of 20 μm to 100 μm. .

  According to the present invention, it is possible to provide an electrophotographic apparatus capable of suppressing the occurrence of shock streaks and H / H initial streaks.

It is a figure which shows typically the place which measures the Young's modulus of a cleaning blade. It is a figure which shows the example of the shape of an opening part when the concave shape part formed in the surface of an electrophotographic photoreceptor is seen from the top. It is a figure which shows the example of fitting. It is a figure which shows typically a relationship, such as a reference plane and a concave shape part. It is a figure which shows the example of the press-contact shape transfer processing apparatus for forming a concave shape part in the surface of an electrophotographic photoreceptor. It is a figure which shows the example of the electrophotographic apparatus of this invention. It is a figure which shows the mold used by the manufacture example of the electrophotographic photoreceptor. It is a figure which shows the outline of the dry-type blasting apparatus used by manufacture example-D11. It is a figure which shows the result of manufacture example-C1 of a cleaning blade.

  The present invention is an electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, an intermediate transfer member, a primary transfer unit, a secondary transfer unit, and an electrophotographic photosensitive member cleaning unit. The following cleaning means for an electrophotographic photosensitive member and an electrophotographic photosensitive member are used. The intermediate transfer member is preferably in the form of a belt.

The electrophotographic photosensitive member cleaning means includes a cleaning member having at least a urethane rubber cleaning blade in contact with the surface of the electrophotographic photosensitive member to clean the surface of the electrophotographic photosensitive member. It is. In the cleaning blade, the Young's modulus (Y ₀ ) of the surface C of the contact portion with the electrophotographic photosensitive member is 10 mgf / μm ² or more and 400 mgf / μm ² or less, and the Young at a position 50 μm inside the surface C is located. rate _{(Y 50)} and the Young's modulus _{(Y 0)} ratio of _(Y 50 / Y ₀₎ is 0.5 or less, and a Young's modulus of 20μm inner position than the surface C and _{(Y 20)} When the average rate of change of Young's modulus from the surface C to the position inside the 20 μm [{(Y ₀ −Y ₂₀ ) / Y ₀ } / (20-0)] is within the 50 μm from the position inside the 20 μm The average change rate of Young's modulus up to the position [{(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20)] or more is characterized.

  On the other hand, the electrophotographic photosensitive member has a plurality of independent concave portions formed on the surface of the electrophotographic photosensitive member. The ratio of the area occupied by the concave portion on the entire surface where the photoconductor and the cleaning blade come into contact is 30% or more and 70% or less. The concave portion has a depth of 0.5 μm or more and 3.0 μm or less, a longest opening diameter of 20 μm or more and 100 μm or less, and a shortest opening diameter of 20 μm or more and 100 μm or less. The longest diameter is preferably 50 μm or more and 100 μm or less.

  The electrophotographic photosensitive member cleaning means and the electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention will be described in order below.

  Hereinafter, for the sake of simplicity, the electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention is also referred to as “electrophotographic photosensitive member of the present invention”. Similarly, the photoconductor cleaning means used in the electrophotographic apparatus of the present invention is also referred to as “cleaning means of the present invention”. Further, as will be described later, the cleaning means of the present invention is characterized by the characteristics of the cleaning blade, and for the sake of simplicity, it is also referred to as “the cleaning blade of the present invention”.

<Description of cleaning means for electrophotographic photosensitive member>
The cleaning means for an electrophotographic photosensitive member of the present invention has at least a cleaning blade made of urethane rubber. Specifically, the cleaning blade made of urethane rubber having a flat plate shape is fixed to the cleaning blade support member. The edge portion of the tip of the cleaning blade is in contact with the surface of the photoconductor, and when the photoconductor rotates, the edge portion rubs against the surface of the photoconductor to scrape off transfer residual toner, foreign matter, and the like. The surface is cleaned.

  On the surface of the electrophotographic photosensitive member of the present invention, a large concave portion having a longest opening diameter and a shortest opening diameter is densely arranged for the purpose of reducing the frictional force acting on the contact portion with the intermediate transfer member. . However, when used in combination with a conventional cleaning blade, the aforementioned H / H initial streak problem occurs. With respect to this cause, the present inventors have found that the conventional cleaning blade does not have sufficient followability to the concave portion formed on the surface of the photosensitive member and low friction, and the sliding state between the cleaning blade and the surface of the photosensitive member is not sufficient. Since it becomes unstable, it is considered that an H / H initial streak occurs. The difference in the rubbing state of the cleaning blade between the concave part on the surface of the photoconductor and the other flat part makes it possible to eliminate memory due to unevenness of how the deposit adheres to the surface of the photoconductor and the rubbing unevenness of the cleaning blade. Presumed to have occurred. Ultimately, these are considered to cause image streaks parallel to the circumferential direction of the photoreceptor.

  On the other hand, the cleaning blade of the present invention has a low friction at the contact portion with the surface of the photoconductor, and has excellent followability to the concave portion formed on the surface of the photoconductor of the present invention. Therefore, the rubbing state between the concave portion on the surface of the photoconductor and the other flat portion is kept uniform, and the cleaning property of the deposits on the surface of the photoconductor is improved. Is also suppressed. As a result, the present inventors consider that the effect of suppressing the H / H initial streak is exhibited.

  In the cleaning blade of the present invention, the surface (hereinafter also referred to as “surface C”) of the contact portion (hereinafter also referred to as “cleaning blade contact portion” or simply “contact portion”) with respect to the photoreceptor. The internal Young's modulus is appropriately controlled. As a result, the surface of the abutting portion is reduced in friction, and a cleaning blade that has excellent conformability to concave portions formed on the surface of the photoreceptor of the present invention and foreign matter that may be present on the surface and is difficult to chip the edge portion is obtained. It is done.

Specifically, the friction of the surface can be reduced by setting the Young's modulus (Y ₀ ) on the surface of the contact portion of the cleaning blade to 10 mgf / μm ² or more. Further, abnormal deformation at the contact portion of the cleaning blade is suppressed.

  The reason why the surface of the contact portion of the cleaning blade is reduced in friction is considered to be because there are fewer microscopic contact points (true contact areas) between the cleaning blade and the surface of the photosensitive member. Due to this low friction, and abnormal deformation of the contact portion of the cleaning blade is less likely to occur, curling of the cleaning blade (edge portion thereof) is suppressed. In addition, since the width of the contact portion of the cleaning blade is stabilized, occurrence of chatter and abnormal noise (squeal) of the cleaning blade is suppressed.

  In the urethane rubber cleaning blade, as a method for increasing the Young's modulus of the contact portion, it is effective to control the molecular structure of the urethane rubber in the vicinity of the contact portion.

  The urethane rubber can be synthesized using, for example, a polyisocyanate, a polyol, a chain extender (for example, a polyfunctional polyol), and a urethane rubber synthesis catalyst.

  When the urethane rubber is a polyester-based urethane rubber, a polyester-based polyol may be used as the polyol in order to synthesize the polyester-based urethane rubber. When the polyester urethane rubber is an aliphatic polyester urethane rubber, an aliphatic polyester polyol may be used as the polyol in order to synthesize the aliphatic polyester urethane rubber.

  As a more specific method for increasing the Young's modulus at the contact portion of the urethane rubber cleaning blade, there is a method of changing the crosslinking density of the urethane rubber or controlling the molecular weight of the raw material of the urethane rubber. Further, as a suitable method, there is a method of increasing the concentration of the isocyanurate group by adding an isocyanurate group to the urethane rubber. An isocyanurate group can be contained in urethane rubber as a group derived from polyisocyanate which is a raw material of urethane rubber.

The cleaning blade of the present invention is preferably a urethane rubber cleaning blade containing an isocyanurate group from the viewpoint of easy control of Young's modulus on the surface of the contact portion. In this case, in order to increase the Young's modulus at the surface of the contact portion of the cleaning blade, it is preferable to increase the content of the isocyanurate groups in the surface of the urethane rubber at the contact portion and in the vicinity thereof. In the present invention, when the urethane rubber is a polyester urethane rubber, the number of isocyanurate groups is compared using the following method. First, the IR spectrum of the surface of the contact portion of the cleaning blade is measured by the μATR method. At this time, attention is focused on the C—N peak intensity derived from the isocyanurate group in the polyester-based urethane rubber (I _SI ) and the C═O peak intensity derived from the ester group in the polyester-based urethane rubber (I _SE ). The C—N peak is a peak at 1411 cm ^{−1 and} the C═O peak is a peak at 1726 cm ⁻¹ . The intensity ratio of these peaks (I _SI / I _SE ) is the C—N peak derived from the isocyanurate group based on the intensity of the C═O peak derived from the ester group not affected by the number of isocyanurate groups. Represents intensity ratio. Therefore, by comparing the values of (I _SI / I _SE ), the number of isocyanurate groups can be compared. In the cleaning blade of the present invention, (I _SI / I _SE ) is preferably 0.50 or more.

From the viewpoint of ensuring followability with respect to the concave portion formed on the surface of the photoreceptor of the present invention, it is not preferable that the Young's modulus of the surface of the cleaning blade is larger than necessary. This is because if the followability to the surface of the photoconductor becomes insufficient, a gap is formed between the cleaning blade and the bottom of the concave portion on the surface of the photoconductor, and the toner can easily pass through. Therefore, Young's modulus at the surface of the contact portion of the cleaning blade of the present invention _{(Y 0)} is preferably at 400mgf / μm ² or less, more preferably 344mgf / μm ² or less, 250mgf / μm ² or less More preferably.

As described above, the cleaning blade of the present invention is a cleaning blade made of urethane rubber containing an isocyanurate group. In order to suppress the Young's modulus (Y ₀ ) on the surface of the contact portion of the cleaning blade to 400 mgf / μm ² or less, the content of isocyanurate groups on the surface (and the vicinity thereof) of the contact portion is set to a certain amount or less. It is preferable to suppress to. Specifically, it is preferable that the ratio (I _SI / I _SE ) is 1.55 or less. In order to suppress the Young's modulus (Y ₀ ) to 344 mgf / μm ² or less, the ratio (I _SI / I _SE ) is preferably 1.35 or less. In order to suppress the Young's modulus (Y ₀ ) to 250 mgf / μm ² or less, the ratio (I _SI / I _SE ) is preferably 1.20 or less.

From the above, the Young's modulus of the surface of the contact portion of the cleaning blade of the present invention _{(Y 0)} is, 10 mgf / [mu] m ² or more 400mgf / μm ² is in the following range, 10 mgf / [mu] m ² or more 344mgf / μm ² or less of It is preferable to be in the range. More preferably, it is the range of 10 mgf / μm ² or more and 250 mgf / μm ² or less. Then, in order to Young's modulus of the surface of the contact portion of the cleaning blade _{(Y 0)} to 10 mgf / [mu] m ² or more 400mgf / μm ² or less of the range, the ratio _(I SI _/ I _SE) is 0.50 It is preferable that it is 1.55 or less. In order to make the Young's modulus (Y ₀ ) in the range of 10 mgf / μm ² or more and 344 mgf / μm ² or less, the ratio (I _SI / I _SE ) is 0.50 or more and 1.35 or less. preferable. That in order further to Young's modulus _{(Y 0)} of 10 mgf / [mu] m ² or more 250mgf / μm ² or less of the range, the ratio _(I SI _/ I _SE) is 0.50 to 1.20 preferable.

In addition, the cleaning blade of the present invention increases the Young's modulus of the surface of the contact portion to a certain degree (10 mgf / μm ² or more and 400 mgf / μm ² or less), and the Young's modulus decreases from the surface of the contact portion toward the inside. It is comprised so that it may become. Specifically, the ratio (Y ₅₀ / Y ₀ ) between the Young's modulus (Y ₅₀ ) and the Young's modulus (Y ₀ ) at a position within 50 μm from the surface of the contact portion of the cleaning blade is 0.5 or less (preferably Is 0.2 or less). Thereby, even if the Young's modulus of the surface of the contact portion is increased to some extent, good followability can be obtained with respect to the concave portion formed on the surface of the photoreceptor of the present invention.

Setting the ratio (Y ₅₀ / Y ₀ ) to 0.5 or less while keeping the Young's modulus (Y ₀ ) in the range of 10 mgf / μm ² or more and 400 mgf / μm ² or less means that the contact portion of the cleaning blade It means that Young's modulus is drastically reduced from the surface to the inside.

  As a result of the study by the present inventors, it has been found that a chipping of the cleaning blade is likely to occur at a location where stress applied to the cleaning blade is concentrated. Further, it has been found that stress concentration is likely to occur at the interface between layers when the cleaning blade is composed of a plurality of layers having different Young's moduli, or at a site where the Young's modulus changes rapidly.

Therefore, as described above, the cleaning blade of the present invention is configured such that the Young's modulus decreases rapidly from the surface of the abutting portion toward the inside, but among them, in the vicinity of the surface of the abutting portion, In particular, the Young's modulus is rapidly reduced. Specifically, the average change rate of Young's modulus from the surface of the contact portion to the position inside 20 μm is configured to be equal to or higher than the average change rate of Young's modulus from the position inside 20 μm to the position inside 50 μm. Yes. The average rate of change in Young's modulus from the surface of the contact portion to the position inside 20 μm is [{(Y ₀ ), where the Young's modulus at the position inside 20 μm from the surface of the contact portion of the cleaning blade is (Y ₂₀ ). -Y _{20) /} Y represented by 0} / (20-0). The average rate of change of Young's modulus from the position inside 20 μm to the position inside 50 μm is represented by [{(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20)]. Thereby, even if the Young's modulus decreases rapidly from the surface of the contact portion toward the inside (inside 50 μm from the surface), the cleaning blade is less likely to be chipped. In addition, the followability to the concave portion formed on the surface of the photoreceptor of the present invention becomes better. This is probably because the Young's modulus suddenly decreases in the vicinity of the surface where the stress due to deformation is large, and the Young's modulus gradually decreases on the inner side, thereby dispersing the stress due to deformation.

Hereinafter, the average change rate [{(Y ₀ −Y ₂₀ ) / Y ₀ } / (20-0)] of Young's modulus from the surface of the contact portion to the position within 20 μm is also expressed as “ΔY _0-20 ”. . In addition, the average change rate [{(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20)] of Young's modulus from the position inside 20 μm to the position inside 50 μm is also expressed as “ΔY _20-50 ”. When expressed using these, the cleaning blade of the present invention is configured to satisfy ΔY _0-20 ≧ ΔY _20-50 .

The cleaning blade of the present invention, as described above, is configured such that the Young's modulus _{(Y 50)} and the Young's modulus _{(Y 0)} and the ratio of _(Y 50 / Y ₀₎ of 0.5 or less Yes. More preferably, the above Young's modulus _{(Y 20)} and the Young's modulus _{(Y 0)} ratio _(Y 20 / Y ₀₎ is configured to be 0.5 or less. Thereby, the followability with respect to the concave-shaped part formed in the surface of the photoreceptor of the present invention becomes better.

In the present invention, the distance between the surface of the contact portion of the cleaning blade (the surface of the contact portion is 0 μm) and the Young's modulus is the vertical axis. Young's modulus (Y _N ) at an arbitrary position (position where the distance from the surface of the abutting portion is N [μm]) in the range from the surface to the inner position of 50 μm (where 0 <N <50 [μm]) Is preferably below the straight line connecting the Young's modulus (Y ₀ ) and the Young's modulus (Y ₅₀ ) (smaller than the straight line). This means that the profile of the change in Young's modulus when projecting from the surface of the contact portion of the cleaning blade toward the inside is convex downward. Thereby, the followability with respect to the concave-shaped part formed in the surface of the photoreceptor of the present invention becomes better.

  In the present invention, the change in Young's modulus of the cleaning blade is not limited to a step change, and may be continuous. The change in Young's modulus of the cleaning blade is preferably continuous rather than stepwise. Being continuous means that there is no interface between portions having different Young's moduli that easily cause peeling or chipping.

  The cleaning blade of the present invention is suitable for local (micro) deformation near the surface of the contact portion of the cleaning blade, such as following ability to the concave portion formed on the surface of the photoconductor of the present invention and suppression of chipping of the edge portion. , The surface area corresponds. The surface region is a region where the Young's modulus decreases from the surface of the contact portion toward the inside as described above. On the other hand, it is preferable that the entire region corresponds to the overall (macro) characteristics such as the deflection of the entire cleaning blade and the change in characteristics due to temperature.

  The internal region is a region inside the surface region. Therefore, it is preferable that the surface area of the cleaning blade is 1/2 or less of the thickness of the cleaning blade.

  Further, the width of the portion (contact portion / nip portion) where the cleaning blade and the member to be cleaned abut is generally several tens to a hundred μm. Therefore, the surface region as described above is preferably present in a range of 2 mm or more from the edge portion of the cleaning blade.

  As described above, the cleaning blade of the present invention is a urethane rubber cleaning blade. Among urethane rubbers, polyester urethane rubber is preferred from the viewpoint of mechanical strength such as wear resistance and difficulty of permanent deformation due to contact pressure (creep resistance), and among them, aliphatic polyester urethane rubber Is more preferable.

  As a method of controlling the Young's modulus of the contact portion of the cleaning blade as described above, it is effective to control the molecular structure of urethane rubber.

  The urethane rubber can be synthesized using, for example, a polyisocyanate, a high molecular weight polyol, a chain extender (for example, a polyfunctional low molecular weight polyol), and a urethane rubber synthesis catalyst. In order to synthesize the polyester-based urethane rubber, a polyester-based polyol may be used as the polyol. In order to synthesize the aliphatic polyester-based urethane rubber, an aliphatic polyester-based polyol may be used as the polyol.

  As a method of controlling the Young's modulus of the contact portion of the cleaning blade made of urethane rubber as described above, specifically, the crosslinking density of the urethane rubber is changed, the molecular weight of the raw material of the urethane rubber is controlled, etc. The method of doing is mentioned. Among these methods, a method in which the concentration of isocyanurate groups derived from polyisocyanate, which is a raw material of urethane rubber, is increased toward the surface side of the urethane rubber is preferable from the viewpoint of accuracy in controlling Young's modulus.

  Examples of the polyisocyanate include 4,4′-diphenylmethane diisocyanate (MDI, 4,4′-MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2, 6-TDI), xylene diisocyanate (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4 Examples include '-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), carbodiimide-modified MDI, polymethylene polyphenyl isocyanate (PAPI), and the like. Among these, 4,4'-diphenylmethane diisocyanate is preferable.

  Examples of the high molecular weight polyol (aliphatic polyester-based polyol) include ethylene butylene adipate polyester polyol, butylene adipate polyester polyol, hexylene adipate polyester polyol, and lactone-based polyester polyol. Moreover, you may mix and use these. Of these aliphatic polyester-based polyols, butylene adipate polyester polyol and hexylene adipate polyester polyol are preferable in terms of high crystallinity. The higher the crystallinity of the aliphatic polyester-based polyol, the higher the hardness of the resulting polyester-based urethane rubber (polyester-based urethane rubber cleaning blade), and the higher the durability of the cleaning blade.

  The number average molecular weight of the high molecular weight polyol is preferably 1500 or more and 4000 or less, and more preferably 2000 or more and 3500 or less. The higher the number average molecular weight of the polyol, the higher the hardness, elastic modulus and tensile strength of the resulting urethane rubber (urethane rubber cleaning blade). Further, the smaller the number average molecular weight, the lower the viscosity and the easier the handling.

  Examples of the chain extender (polyfunctional low molecular weight polyol) include glycol. Examples of the glycol include ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), and 1,6-hexanediol. (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), triethylene glycol and the like. Examples of chain extenders other than glycol include trihydric or higher polyhydric alcohols. Examples of the trihydric or higher polyhydric alcohol include trimethylolpropane, glycerin, pentaerythritol, sorbitol, and the like. Moreover, you may mix and use these.

  Urethane rubber synthesis catalysts are roughly classified into urethanization catalysts (reaction promotion catalysts) for promoting rubberization (resinization) and foaming, and isocyanurate formation catalysts (isocyanate trimerization catalysts). In the present invention, these may be mixed and used.

  Examples of urethanization catalysts include tin-based urethanization catalysts such as dibutyltin dilaurate and stannous octoate, triethylenediamine, tetramethylguanidine, pentamethyldiethylenetriamine, dimethylimidazole, tetramethylpropanediamine, N, N, and N. Examples include amine-based urethanization catalysts such as' -trimethylaminoethylethanolamine. In the present invention, these may be mixed and used. Among these urethanization catalysts, triethylenediamine is preferable in that the urethane reaction is particularly accelerated.

Examples of the isocyanuration catalyst include metal oxides such as Li ₂ O and (Bu ₃ Sn) ₂ O, hydride compounds such as NaBH ₄ , NaOCH ₃ , KO— (t-Bu), and borate. Alkoxide compounds such as, amine compounds such as N (C ₂ H ₅ ) ₃ , N (CH ₃ ) ₂ CH ₂ C ₂ H ₅ , N ₂ C ₆ H ₁₂ , HCO ₂ Na, CO ₃ (Na) ₂ , PhCO ₂ Na / DMF, CH ₃ CO ₂ K, (CH ₃ CO ₂ ) ₂ Ca, alkaline soap, naphthenate, and other alkaline carboxylate salt compounds, alkaline formate compounds, ((R ¹ ) ₃ − NR ² OH) -OOCR ³ quaternary ammonium salt compounds such as and the like. Examples of the combined catalyst (co-catalyst) used as the isocyanurate-forming catalyst include amine / epoxide, amine / carboxylic acid, and amine / alkylene imide. In the present invention, these may be mixed and used.

  Among the urethane rubber synthesis catalysts, N, N, N'-trimethylaminoethylethanolamine, which exhibits an action of an isocyanurate catalyst in addition to an action as a urethanization catalyst alone, is preferable.

  Moreover, additives, such as a pigment, a plasticizer, a waterproofing agent, antioxidant, a ultraviolet absorber, a light stabilizer, can also be used together as needed.

  The present inventors have found that the distribution of isocyanurate groups can be controlled as described above by synthesizing urethane rubber by the following method. That is, an aliphatic polyester-based polyol is used as a polyol, an isocyanurate-forming catalyst is applied to the inner surface of a mold, and a raw material in which the ratio of polyisocyanate and aliphatic polyester-based polyol is within a specific range is put in this mold, This is a method of synthesizing rubber.

  By applying the isocyanurate forming catalyst to the inner surface of the mold into which the raw material is put, the isocyanurate forming reaction is promoted particularly in the portion in contact with the inner surface of the mold. Therefore, it is preferable to use excess polyisocyanate with respect to the aliphatic polyester-based polyol. Furthermore, the isocyanurate-forming catalyst applied to the inner surface of the mold and the temperature of the mold act on the excess polyisocyanate to synthesize urethane rubber whose distribution of isocyanurate groups is controlled as described above. Is done.

The use amount (number of moles) of the aliphatic polyester-based polyol with respect to the polyisocyanate is preferably 30 mol% or more and 40 mol% or less with respect to the number of moles of the polyisocyanate. The smaller the aliphatic polyester-based polyol is, the more easily the effect of excess polyisocyanate is obtained, and the Young's modulus (Y ₀ ) of the surface of the contact portion of the cleaning blade is easily controlled to 10 mgf / μm ² or more. On the other hand, by suppressing the excessive degree of polyisocyanate to some extent, the Young's modulus (Y ₀ ) of the surface of the contact portion of the cleaning blade can be easily controlled to 400 mgf / μm ² or less.

  The mold temperature is preferably in the range of 80 ° C. or higher and 150 ° C. or lower, and more preferably in the range of 100 ° C. or higher and 130 ° C. or lower. In order to synthesize urethane rubber by reacting raw materials in the mold, it is preferable that the temperature of the mold is high to some extent from the viewpoint of reaction speed, but the surface of the contact portion increases as the temperature of the mold increases. And the difference in Young's modulus inside tends to be small.

  As a method for manufacturing the cleaning blade, in addition to the above-described method, for example, a method in which a liquid is poured into a drum-shaped mold and a centrifugal force is applied (centrifugal method), or a belt or groove-shaped method is used. Examples include a method of casting a liquid into a mold and molding (cast press method).

  When a cleaning blade for a photoconductor is installed in an electrophotographic apparatus, the cleaning blade is generally used in a form fixed to a support member. Examples of the method of supporting the cleaning blade include a method of bonding the cleaning blade to the support member, and a method of sandwiching the cleaning blade with a plurality of support members. In addition, as another method for supporting the cleaning blade, for example, a method of forming a cleaning blade at the tip of a support member (a method in which a part of the cleaning blade is used as a support portion) and the like can be given.

  The cleaning blade of the present invention may be employed in a counter system in which the cleaning blade is disposed in a counter direction with respect to the rotation direction of the photoconductor during image formation (the movement direction of the photoconductor surface) as a contact method with the photoconductor surface. it can. Moreover, the with system arrange | positioned in a with direction can also be employ | adopted. By adopting the with method, it becomes easy to keep the wedge shape and the contact pressure formed between the surface of the photosensitive member and the tip of the cleaning blade in a good state. If the wedge shape and the contact pressure are in a good state, the followability to the concave portion formed on the surface of the photoreceptor of the present invention is excellent, and excellent cleaning properties are obtained and the rotational torque of the photoreceptor is obtained. Can be reduced.

(Measurement method of Young's modulus)
In the present invention, the Young's modulus of the cleaning blade was measured using a microindentation hardness tester (trade name: ENT-1100, manufactured by Elionix Co., Ltd.). At an appropriate point from the surface of the contact portion of the cleaning blade to the inside, a load-unloading test is performed under the following conditions, and a Young's modulus is obtained as a calculation result of the testing machine.
Test mode: Load-unloading test Load range: A
Test load: 100 [mgf]
Number of divisions: 1000 [times]
Step interval: 10 [msec]
Load holding time: 2 [sec]
FIG. 1 is a schematic diagram illustrating a place where the Young's modulus of the cleaning blade is measured.

  In the present invention, the cleaning blade was first divided into four equal parts in the longitudinal direction. Then, at any point of the contact portion 806 (gray area in the lower side of FIG. 1) on the three cut surfaces 805 excluding both ends, the direction from the surface of the contact portion toward the inside (FIG. 1). The measurement and calculation described above were performed in the direction of the arrow in the lower diagram. Specifically, from the surface of the contact portion toward the inside, the above-described measurement and calculation were performed at positions of 2 μm from the surface to 60 μm, 10 μm from 60 μm to 100 μm, and 20 μm from 100 μm to 300 μm. And the value which averaged the measured value in the said three cross section in each measurement position was used as the value of the Young's modulus in the position. In principle, the Young's modulus is greater than zero.

(Measurement method of IR spectrum by μATR method)
In the present invention, the IR spectrum was measured by the μATR method using a Fourier transform infrared spectrometer (trade name: Perkin Elmer Spectrum One / Spotlight 300, manufactured by PerkinElmer) (universal ATR of diamond crystal).

(Measurement method of number average molecular weight)
In the present invention, the number average molecular weight is a gel permeation chromatography (GPC) method, using monodispersed polystyrene for GPC, and creating a calibration curve from the peak count number and the number average molecular weight of the monodisperse polystyrene, Calculation was performed according to a conventional method. Specifically, in the present invention, the number average molecular weight is a value obtained by dissolving the measurement target with tetrahydrofuran (solvent) and measuring the dissolved components under the following apparatus and conditions.
GPC device: HLC-8120GPC (trade name) manufactured by Tosoh Corporation
Column: TSK-GEL (trade name), G-5000HXL (trade name), G-4000HXL (trade name), G-3000HXL (trade name), G-2000HXL (trade name) manufactured by Tosoh Corporation
Detector: Differential refractometer Solvent: Tetrahydrofuran solvent concentration: 0.5% by mass
Flow rate: 1.0 ml / min
<Description of electrophotographic photoreceptor>
Next, the electrophotographic photoreceptor of the present invention will be described.

  In the present invention, for the purpose of reducing shock lines, a plurality of independent concave portions are formed on the surface of the photoconductor in order to reduce the frictional force acting when the photoconductor and the intermediate transfer body are in direct contact. More specifically, in order to reduce the true contact area between the surface of the photosensitive member and the surface of the intermediate transfer member without interposing the toner, the longest diameter of the opening and the surface of the photosensitive member are reduced. A concave-shaped part having a large opening shortest diameter is closely arranged.

According to our study,
The depth of the concave portion is 0.5 μm or more and 3.0 μm or less,
The longest diameter of the opening is 20 μm or more and 100 μm or less, and
The shortest diameter of the opening is 20 μm or more and 100 μm or less,
The effect of improving the shock streak was observed in the photoconductor in which the ratio of the area occupied by the concave portion on the entire surface where the photoconductor and the cleaning blade are in contact is 30% to 70%.

  In the tandem electrophotographic apparatus, a plurality of photosensitive members are in contact with the intermediate transfer member, and each contact nip portion may cause a shock stripe. When the intermediate transfer member is an intermediate transfer belt, it is necessary to consider the influence of the deflection of the intermediate transfer belt. The photoconductor of the present invention has the effect of suppressing the relative change itself in the peripheral speed between the photoconductor and the intermediate transfer member, which causes shock streaks. Therefore, the tandem type electrophotographic apparatus equipped with the intermediate transfer belt is provided. Can be suitably used.

  The concave portion or flat portion on the surface of the electrophotographic photosensitive member of the present invention can be observed using a microscope such as a laser microscope, an optical microscope, an electron microscope, or an atomic force microscope.

As the laser microscope, for example, the following devices can be used.
Keyence Co., Ltd. ultra-deep shape measurement microscope VK-8550 (trade name), ultra-deep shape measurement microscope VK-9000 (trade name), ultra-deep shape measurement microscope VK-9500 (trade name), VK-X200 (trade name) ), VK-X100 (trade name)
Scanning confocal laser microscope OLS3000 (trade name) manufactured by Olympus Corporation
Lasertec Real Color Confocal Microscope Oplitex C130 (trade name)
As the optical microscope, for example, the following devices can be used.
Digital Microscope VHX-500 (trade name), Digital Microscope VHX-200 (trade name) manufactured by Keyence Corporation
OMRON 3D Digital Microscope VC-7700 (trade name)
As the electron microscope, for example, the following devices can be used.
KEYENCE 3D Real Surface View Microscope VE-9800 (trade name), 3D Real Surface View Microscope VE-8800 (trade name)
SII Nano Technology Co., Ltd. Scanning Electron Microscope Conventional / Variable Pressure SEM (trade name)
Scanning electron microscope SUPERSCAN SS-550 (trade name) manufactured by Shimadzu Corporation
As the atomic force microscope, for example, the following devices can be used.
Keyence Corporation nanoscale hybrid microscope VN-8000 (trade name)
Scanning probe microscope NanoNavi station (trade name) manufactured by SII Nano Technology
Scanning probe microscope SPM-9600 (trade name) manufactured by Shimadzu Corporation
In the present invention, a square region having a side of 500 μm was observed using a laser microscope, and the longest opening diameter, the shortest opening diameter and depth of the concave portion were measured, and the area occupied by the concave portion in the square region was measured. . Note that the observation of a square region having a side of 500 μm may be performed at a magnification such that the square region having a side of 500 μm can be accommodated, or after performing partial observation at a higher magnification, a plurality of partial images can be obtained using software. You may make it connect.

  As the shape of the opening of the concave portion formed on the surface of the electrophotographic photosensitive member of the present invention, for example, a circle, an ellipse, a square, a rectangle, a triangle, as shown in FIGS. Examples include pentagons and hexagons. In addition, as the cross-sectional shape of the concave portion, for example, those having edges such as triangles, quadrilaterals, polygons, corrugations consisting of continuous curves, and some or all of the edges of triangles, quadrilaterals, polygons The one transformed into a curve is mentioned.

  The plurality of concave-shaped portions provided on the surface of the electrophotographic photosensitive member may all have the same shape, the longest diameter of the opening, the shortest diameter of the opening, and the depth, or a different shape, the longest diameter of the opening, and the opening. The parts with the shortest diameter and depth may be mixed.

  Next, terms such as the longest diameter of the opening, the shortest diameter of the opening, and the depth of the concave portion used in the present invention will be described.

  First, the surface of the electrophotographic photoreceptor is enlarged and observed with a microscope. For example, when the surface (circumferential surface) of the electrophotographic photosensitive member is a curved surface curved in the circumferential direction as in the case where the electrophotographic photosensitive member is cylindrical, a cross-sectional profile of the curved surface is extracted and a curved line ( If the electrophotographic photosensitive member is cylindrical, an arc) is fitted. FIG. 3 shows an example of fitting. The example shown in FIG. 3 is an example where the electrophotographic photosensitive member is cylindrical. In FIG. 3, a solid line 101 is a cross-sectional profile of the surface (curved surface) of the electrophotographic photosensitive member, and a broken line 102 is a curve fitted to the cross-sectional profile 101. The cross-sectional profile 101 is corrected so that the curve 102 is a straight line, and a surface obtained by extending the obtained straight line in the longitudinal direction (direction perpendicular to the circumferential direction) of the electrophotographic photosensitive member is used as a reference surface. Even when the electrophotographic photosensitive member is not cylindrical, the reference surface is obtained in the same manner as when the electrophotographic photosensitive member is cylindrical.

  A portion located below the obtained reference plane is defined as a concave portion in the square region. The distance from the reference surface to the lowest point of the concave portion is defined as the depth of the concave portion. Let the cross section of the concave shape part by a reference surface be an opening part, and let the length of the longest line segment among the line segments which cross | intersect an opening part be an opening part longest diameter of a concave shape part. Moreover, let the distance when the distance of the two parallel lines which pinch | interpose the opening part of a concave shape part become the shortest be the opening part shortest diameter of a concave shape part. The depth thus obtained is in the range of 0.5 μm to 3.0 μm, the longest diameter of the opening is in the range of 20 μm to 100 μm, and the shortest of the opening is in the range of 20 μm to 100 μm. Corresponds to the concave portion formed on the surface of the photoreceptor of the present invention. Note that, as in the case where the opening is circular, the longest diameter of the opening and the shortest diameter of the opening may have the same length. The depth of the concave portion is more preferably 0.5 μm or more and 2.0 μm or less from the viewpoint of the followability of the cleaning blade to the concave portion. The concave portion may be formed on the entire surface of the electrophotographic photosensitive member, or may be formed on a part of the surface of the electrophotographic photosensitive member. However, when the concave-shaped portion is formed on a part of the surface of the electrophotographic photosensitive member, the concave-shaped portion needs to be formed at least over the entire region where toner can exist on the surface of the photosensitive member. Therefore, in the electrophotographic photoreceptor of the present invention, the concave portion is formed on the entire surface where the photoreceptor and the cleaning blade come into contact.

  In order to reduce the true contact area with the intermediate transfer member, the longest opening diameter, the shortest opening diameter, and the depth of the concave portion in the present invention satisfy the above-mentioned conditions. In addition, the concave portion having such a shape is formed on the surface of the photoconductor so that the ratio of the area occupied by the concave portion is 30% or more and 70% or less on the entire surface where the photoconductor and the cleaning blade come into contact with each other. It is formed. When the concave-shaped portion is formed on the surface of the photosensitive member so that the ratio of the area occupied by the concave-shaped portion is 50% or more and 70% or less on the entire surface where the photosensitive member and the cleaning blade come into contact with each other, the intermediate transfer member This is more preferable because the true contact area becomes smaller.

  Note that the area occupied by the concave portion means the total area of the openings of the concave portion formed on the surface of the photosensitive member. Further, the ratio of the area occupied by the concave portion is the sum of the areas of the openings of the concave portion formed on the entire surface where the photosensitive member of the present invention and the cleaning blade are in contact with each other. It means the proportion of the total surface area that comes into contact. The ratio of the area occupied by the concave portion on the entire surface where the photoconductor and the cleaning blade abut may be obtained by observing the entire area where the photoconductor and the cleaning blade abut. In addition, when the concave portion is uniformly formed on the surface of the photoconductor, it may be estimated from the measurement results at a plurality of locations on the surface of the photoconductor. For example, first, a square area having a size in which all of the plurality of concave-shaped parts are included is taken on the surface of the photosensitive member, and the ratio of the area of the opening of the concave-shaped part in the square area is obtained. Next, this measurement is repeated a plurality of times by selecting arbitrary points on the entire surface where the photosensitive member and the cleaning blade are in contact with each other so as not to overlap each other. By taking the average of the obtained results, it is possible to estimate the ratio of the area occupied by the concave portion on the entire surface where the photosensitive member and the cleaning blade come into contact. In the present invention, observation was performed by taking a square region of 500 μm on each side at arbitrary 50 locations selected so as not to overlap each other on the entire surface where the photoreceptor and the cleaning blade contact each other. Then, the ratio of the area occupied by the concave portion on the entire surface where the photosensitive member and the cleaning blade contact each other was estimated by taking the average ratio of the concave portion measured in each square region. Hereinafter, for the sake of simplicity, the ratio of the area occupied by the concave portion thus obtained is also referred to as “area ratio”.

  FIG. 4 schematically shows the relationship between the reference surface 2-1, the concave portion 2-2 (concave portion), and the like. FIG. 4 is a cross-sectional profile after the above correction.

<Method of forming a concave portion on the surface of an electrophotographic photosensitive member>
Next, a method for forming an independent concave portion on the surface of the electrophotographic photosensitive member will be described.

  The concave shape portion can be formed on the surface of the electrophotographic photosensitive member by pressing a mold having a convex portion corresponding to the concave shape portion to be formed on the surface of the electrophotographic photosensitive member and performing shape transfer.

  FIG. 5 shows an example of a press-contact shape transfer processing apparatus for forming a concave portion on the surface of the electrophotographic photosensitive member.

  According to the press-contact shape transfer processing apparatus shown in FIG. 5, the mold 5-2 is continuously brought into contact with the surface (circumferential surface) and pressed while rotating the electrophotographic photosensitive member 5-1, which is a workpiece. Thus, a concave portion or a flat portion can be formed on the surface of the electrophotographic photosensitive member 5-1.

  Examples of the material of the pressure member 5-3 include metal, metal oxide, plastic, and glass. Among these, stainless steel (SUS) is preferable from the viewpoint of mechanical strength, dimensional accuracy, and durability. The pressure member 5-3 is provided with a mold on its upper surface. Further, the mold 5-2 is applied to the surface of the electrophotographic photosensitive member 5-1 supported by the support member 5-4 with a predetermined pressure by a support member (not shown) on the lower surface side and a pressure system (not shown). Can be contacted. Further, the support member 5-4 may be pressed against the pressure member 5-3 with a predetermined pressure, or the support member 5-4 and the pressure member 5-3 may be pressed against each other.

  The example shown in FIG. 5 is an example in which the surface of the electrophotographic photosensitive member 5-1 is continuously processed while being driven or driven and rotated by moving the pressing member 5-3. Further, the electrophotographic photosensitive member 5 is fixed by fixing the pressure member 5-3 and moving the support member 5-4, or by moving both the support member 5-4 and the pressure member 5-3. The surface of -1 can also be processed continuously.

  From the viewpoint of efficiently transferring the shape, it is preferable to heat the mold 5-2 and the electrophotographic photosensitive member 5-1.

  As the mold 5-2, for example, a fine surface-treated metal or resin film, or a surface of a silicon wafer or the like patterned with a resist can be used. In addition, a resin film in which fine particles are dispersed, a resin film having a fine surface shape, and a metal coating are used.

  Moreover, it is preferable to install an elastic body between the mold 5-2 and the pressure member 5-3 from the viewpoint of making the pressure pressed against the electrophotographic photosensitive member uniform.

<Configuration of electrophotographic photoreceptor>
The electrophotographic photoreceptor of the present invention is a cylindrical electrophotographic photoreceptor having a support and a photosensitive layer formed on the support.

  The photosensitive layer is a single layer type photosensitive layer containing a charge transporting material and a charge generating material in the same layer, but is separated into a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material. A (functional separation type) photosensitive layer may be used. From the viewpoint of electrophotographic characteristics, a laminated photosensitive layer is preferred. The laminated photosensitive layer is preferably a normal photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side. In addition, the charge generation layer may have a stacked structure, and the charge transport layer may have a stacked structure.

  The support is preferably one that exhibits conductivity (conductive support). Examples of the material of the support include metals (alloys) such as iron, copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony, indium, chromium, aluminum alloy, and stainless steel. In addition, for example, a metal support or a plastic support having a film formed by vacuum deposition using aluminum, an aluminum alloy, or an indium oxide-tin oxide alloy can be used.

  In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated with plastic or paper, or a support formed with a conductive binder resin can also be used.

  The surface of the support may be subjected to, for example, a cutting process, a roughening process, or an alumite process for the purpose of suppressing interference fringes due to scattering of laser light.

  For example, a conductive layer may be provided between the support and the undercoat layer described below for the purpose of suppressing interference fringes due to scattering of laser light and covering the scratches on the support. The conductive layer is formed by applying a coating solution for conductive layer obtained by dispersing carbon black, conductive pigment, and resistance adjusting pigment in a solvent together with a binder resin to form a coating film, and then drying the obtained coating film. Can be formed. Moreover, you may add to the coating liquid for conductive layers the compound which hardens and polymerizes by heating, ultraviolet irradiation, and radiation irradiation, for example.

  Examples of the binder resin used for the conductive layer include acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, phenol resin, butyral resin, poly Examples thereof include acrylate resins, polyacetal resins, polyamideimide resins, polyamide resins, polyallyl ether resins, polyimide resins, polyurethane resins, polyester resins, polycarbonate resins, and polyethylene resins.

  Examples of the conductive pigment and the resistance adjusting pigment include particles of metal (alloy) such as aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, and those obtained by vapor deposition on the surface of plastic particles. It is also possible to use metal oxide particles such as zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony or tantalum-doped tin oxide. it can.

  These may be used alone or in combination of two or more. Further, the conductive pigment and the resistance adjusting pigment can be subjected to a surface treatment. As the surface treatment agent, for example, a surfactant, a silane coupling agent, or a titanium coupling agent is used.

  Furthermore, for the purpose of light scattering, particles such as silicone resin fine particles and acrylic resin fine particles may be added. Moreover, you may contain additives, such as a leveling agent, a dispersing agent, antioxidant, a ultraviolet absorber, a plasticizer, and a rectifying material.

  The thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less, more preferably 1 μm or more and 35 μm or less, and more preferably 5 μm or more and 30 μm or less.

  An undercoat layer (intermediate layer) is provided between the support or conductive layer and the photosensitive layer (charge generation layer, charge transport layer) for the purpose of improving adhesion of the photosensitive layer and improving charge injection from the support. It may be provided. The undercoat layer can be formed by forming a coating film of the coating solution for the undercoat layer obtained by mixing the binder resin and the solvent, and drying the coating film.

  Examples of the resin used for the undercoat layer include polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methyl cellulose, casein, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, N-alkoxymethylated nylon, etc.), polyurethane resin , Acrylic resin, allyl resin, alkyd resin, phenol resin, and epoxy resin.

  The thickness of the undercoat layer is preferably 0.05 μm or more and 40 μm or less.

  The undercoat layer may contain metal oxide particles. The metal oxide particles used for the undercoat layer are preferably particles containing at least one selected from the group consisting of titanium oxide, zinc oxide, tin oxide, zirconium oxide, and aluminum oxide. Among the particles containing the above metal oxide, particles containing zinc oxide are more preferable.

  The metal oxide particles may be particles in which the surface of the metal oxide particles is treated with a surface treatment agent such as a silane coupling agent.

  Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, and a liquid collision type high-speed disperser.

  The undercoat layer may further contain, for example, organic resin particles or a leveling agent for the purpose of adjusting the surface roughness of the undercoat layer or reducing cracks in the undercoat layer. As organic resin particles, hydrophobic organic resin particles such as silicone particles and hydrophilic organic resin particles such as cross-linked polymethacrylate resin (PMMA) particles can be used.

  Various additives can be contained in the undercoat layer. Examples of the additive include organic metal compounds such as metals, conductive substances, electron transport substances, metal chelate compounds, and silane coupling agents.

  When the photosensitive layer is a laminated photosensitive layer, the charge generation layer is formed by applying a charge generation layer coating solution obtained by dispersing the charge generation material together with a binder resin and a solvent to form a coating film, and then drying it. Can be formed. The charge generation layer may be a vapor generation film of a charge generation material.

  Examples of the charge generating material used in the photosensitive layer include azo pigments, phthalocyanine pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, squarylium dyes, thiapyrylium salts, triphenylmethane dyes, and quinacridone pigments. Examples include azulenium salt pigments, cyanine dyes, anthanthrone pigments, pyranthrone pigments, xanthene dyes, quinoneimine dyes, and styryl dyes.

  These charge generation materials may be used alone or in combination of two or more. Among these, oxytitanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine are preferable from the viewpoint of sensitivity. Furthermore, among the hydroxygallium phthalocyanines, there are hydroxygallium phthalocyanine crystals having crystal forms having strong peaks at Bragg angles 2θ of 7.4 ° ± 0.3 ° and 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction. preferable.

  Examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, butyral resin, polyvinyl acetal resin, acrylic resin, vinyl acetate resin, and urea resin. Among these, a butyral resin is preferable. These may be used alone or in combination as a mixture or copolymer.

  Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, and an attritor.

  The ratio of the charge generation material and the binder resin in the charge generation layer is preferably 0.3 parts by mass or more and 10 parts by mass or less of the charge generation material with respect to 1 part by mass of the binder resin. If necessary, for example, a sensitizer, a leveling agent, a dispersant, an antioxidant, an ultraviolet absorber, a plasticizer, and a rectifying material can be added to the charge generation layer. The thickness of the charge generation layer is preferably from 0.01 μm to 5 μm, and more preferably from 0.1 μm to 2 μm.

  When the photosensitive layer is a laminated photosensitive layer, a charge transport layer is formed on the charge generation layer. The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent to form a coating film and drying the coating film.

  Examples of the charge transport material include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds, A butadiene compound is mentioned. These charge transport materials may be used alone or in combination of two or more. Among these charge transport materials, a triphenylamine compound is preferable from the viewpoint of charge mobility.

  Examples of the binder resin used for the charge transport layer include polyester resin, acrylic resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polyvinyl butyral resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, and vinylidene chloride. , Acrylonitrile copolymer, and polyvinyl benzal resin. These may be used alone or in combination as a mixture or copolymer.

  If necessary, for example, an antioxidant, an ultraviolet absorber, a plasticizer, and a leveling agent can be added to the charge transport layer.

  The ratio of the charge transport material and the binder resin in the charge transport layer is preferably 0.3 parts by mass or more and 10 parts by mass or less of the charge transport material with respect to 1 part by mass of the binder resin. When the charge transport layer is a single layer, the thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less, and more preferably 8 μm or more and 30 μm or less. When the charge transport layer has a laminated structure, the thickness of the charge transport layer on the support side is preferably 5 μm to 30 μm, and the thickness of the charge transport layer on the surface side is preferably 1 μm to 10 μm. preferable.

  Examples of the solvent used in the coating solution for the charge generation layer and the charge transport layer include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, halogenated hydrocarbon solvents, and aromatic solvents. Is mentioned.

  A protective layer may be formed on the charge transport layer for the purpose of improving the abrasion resistance and cleaning properties of the electrophotographic photosensitive member. The protective layer can be formed by forming a coating film of a coating solution for the protective layer obtained by dissolving the binder resin in a solvent and drying the coating film.

  Examples of the resin used for the protective layer include polyvinyl butyral resin, polyester resin, polycarbonate resin, polyamide resin, polyimide resin, polyurethane resin, phenol resin, and polyarylate resin.

  In addition, the protective layer is formed by forming a coating film of a coating solution for the protective layer obtained by dissolving a polymerizable monomer or oligomer in a solvent, and curing (polymerizing) the coating film using a crosslinking or polymerization reaction. May be formed. Examples of the polymerizable monomer or oligomer include a compound having a chain polymerizable functional group such as an acryloyloxy group and a styryl group, and a sequentially polymerizable functional group such as a hydroxy group, an alkoxysilyl group, an isocyanate group, and an epoxy group. Compounds.

  Examples of the curing reaction include radical polymerization, ionic polymerization, thermal polymerization, photopolymerization, radiation polymerization (electron beam polymerization), plasma CVD method, and photo CVD method.

  In addition, conductive particles or a charge transport material may be added to the protective layer. As the conductive particles, a conductive pigment used in the conductive layer can be used. As the charge transport material, the above-described charge transport materials can be used.

  Furthermore, it is more preferable to use a charge transport material having a polymerizable functional group from the viewpoint of achieving both wear resistance and charge transport capability. As the polymerizable functional group, an acryloyloxy group is preferred. Further, a charge transport material having two or more polymerizable functional groups in the same molecule is preferable.

  Further, the surface layer (charge transport layer or protective layer) of the electrophotographic photoreceptor may contain organic resin particles or inorganic particles. Examples of the organic resin particles include fluorine atom-containing resin particles and acrylic resin particles. Inorganic particles include alumina, silica, and titania. Furthermore, you may add electroconductive particle, antioxidant, a ultraviolet absorber, a plasticizer, a leveling agent, etc.

  The thickness of the protective layer is preferably from 0.1 to 30 μm, and more preferably from 1 to 10 μm.

As a method of applying the coating solution for each layer, for example, a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, and a blade coating method can be used. Configuration of photographic device>
FIG. 6 shows a configuration example of the electrophotographic apparatus of the present invention. However, the embodiment of the electrophotographic apparatus of the present invention is not limited to this.

  The electrophotographic apparatus 900 is a laser beam printer that uses a tandem method and uses an intermediate transfer belt as an intermediate transfer member.

  The electrophotographic apparatus 900 includes first, second, third, and fourth image forming units (stations) SY, SM, SC, and SK as a plurality of image forming units. The first, second, third, and fourth image forming units SY, SM, SC, and SK form yellow (Y), magenta (M), cyan (C), and black (K) images, respectively. It is supposed to be.

  The configurations and operations of the image forming units SY, SM, SC, and SK are substantially the same except that the color of the toner used is different. Therefore, in the following, when there is no particular need to distinguish, subscripts (Y, M, C, and K) given to the reference numerals in the drawings are omitted to indicate that the elements are provided for any color. A general description.

  The image forming unit S includes an electrophotographic photoreceptor 901. The electrophotographic photoreceptor 901 is rotationally driven in the direction of arrow R1 (clockwise) in the drawing. Around the electrophotographic photoreceptor 901, a contact charging member (charging roller) 902 as a charging unit, a laser beam scanner 903 as an image exposure unit, a developing device 904 as a developing unit, and a cleaning device 909 are arranged. The cleaning device 909 is a cleaning unit for the electrophotographic photosensitive member. Further, an intermediate transfer belt 906 is disposed so as to be in contact with the electrophotographic photoreceptor 901 of all the image forming units S, and a primary transfer roller 905 is disposed such that the intermediate transfer belt 906 is sandwiched between the electrophotographic photoreceptor 901. ing.

  Next, an image forming operation (image forming method) will be described taking full color image formation as an example.

  First, the surface of the electrophotographic photosensitive member 901 is uniformly charged by the charging roller 902 to a predetermined potential having a predetermined polarity (negative polarity in this embodiment). The electrophotographic photosensitive member 901 rotates at a constant peripheral speed (surface movement speed) in the direction of arrow R1 in the figure. The peripheral speed of the electrophotographic photosensitive member 901 corresponds to the process speed of the electrophotographic apparatus 900.

  The surface of the charged electrophotographic photosensitive member 901 is scanned and exposed by a laser beam scanner (image exposure apparatus) 903 with a laser beam L modulated by an image signal. Since the charged charge on the surface of the electrophotographic photosensitive member 901 is canceled at the portion irradiated with the laser light, an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member 901.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 901 is developed as a toner image by toner stored in the developing device 904.

  Each color toner image formed on the surface of each electrophotographic photosensitive member 901 is transferred to an intermediate transfer belt at a primary transfer portion where the primary transfer roller 905 and the electrophotographic photosensitive member 901 face each other with the intermediate transfer belt 906 interposed therebetween. The images are sequentially superimposed and transferred (primary transfer) on 906. At this time, a primary transfer voltage having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer roller 905.

  The intermediate transfer belt 906 is rotationally driven by a driving roller 961, and the toner images superimposed on the four colors on the surface of the intermediate transfer belt 906 are electrostatically collectively transferred to a transfer material M such as paper by a secondary transfer unit 907. And transferred.

  The transfer material M onto which the toner image has been transferred is separated from the intermediate transfer belt 906 and conveyed to a fixing device (thermal roller fixing device) 908 as fixing means. The unfixed toner image on the transfer material M is fixed on the transfer material M by being heated and pressurized by the fixing device 908.

  Toner remaining on the surface of the electrophotographic photosensitive member 901 without being transferred to the intermediate transfer belt 906 after the primary transfer step (primary transfer residual toner) is removed from the surface of the electrophotographic photosensitive member 901 by the cleaning device 909 and collected. . The electrophotographic photoreceptor 901 from which the primary transfer residual toner has been removed is repeatedly used for image formation. It should be noted that a charge eliminating step (not shown) may be provided between the primary transfer process and the cleaning process, or between the cleaning process and the charging process.

  Finally, the toner remaining on the surface of the intermediate transfer belt 906 without being transferred to the transfer material M after the secondary transfer step (secondary transfer residual toner) is removed from the surface of the intermediate transfer belt 906 by the intermediate transfer belt cleaner 910. To be recovered.

  The electrophotographic apparatus of the present invention uses a process cartridge that has at least one of an electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, a cleaning unit, and a charge eliminating unit, and is detachable from the electrophotographic apparatus. You may be the composition which was.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. In the examples, “part” means “part by mass”.

<Example of production of electrophotographic photoreceptor>
(Production Example-D1)
An aluminum cylinder having a diameter of 30 mm and a length of 357.5 mm was used as a support (cylindrical support).

Next, 100 parts of zinc oxide particles (specific surface area: 19 m ² / g, powder resistance: 4.7 × 10 ⁶ Ω · cm) as a metal oxide are stirred and mixed with 500 parts of toluene, and this is mixed with a silane coupling agent. (Compound name: N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.8 part was added and stirred for 6 hours. Thereafter, toluene was distilled off under reduced pressure, followed by heating and drying at 130 ° C. for 6 hours to obtain surface-treated zinc oxide particles.

  Next, 15 parts of butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and 15 parts of blocked isocyanate (trade name: Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as polyol resin were added to methyl ethyl ketone 73. It was dissolved in a mixed solution of 5 parts and 73.5 parts of 1-butanol. To this solution, 80.8 parts of the surface-treated zinc oxide particles and 0.8 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and this was added to a glass having a diameter of 0.8 mm. Dispersion was performed in a sand mill apparatus using beads in an atmosphere of 23 ± 3 ° C. for 3 hours. After dispersion, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Silicone), crosslinked polymethyl methacrylate (PMMA) particles (trade name: TECHPOLYMER SSX-102, manufactured by Sekisui Plastics Co., Ltd.) 5.6 parts of an average primary particle size of 3.0 μm) was added and stirred to prepare an undercoat layer coating solution.

  This undercoat layer coating solution was applied onto the support by dip coating, and the resulting coating film was dried at 160 ° C. for 40 minutes to form an undercoat layer having a thickness of 18 μm.

  Next, 20 parts of a crystalline hydroxygallium phthalocyanine crystal (charge generation material) having strong peaks at 7.4 ° and 28.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction, the following structural formula 0.2 part of a calixarene compound represented by (A),

  10 parts of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 600 parts of cyclohexanone were placed in a sand mill using glass beads having a diameter of 1 mm. Then, after dispersing for 4 hours, 700 parts of ethyl acetate was added to prepare a charge generation layer coating solution. The charge generation layer coating solution was dip-coated on the undercoat layer, and the resulting coating film was dried at 80 ° C. for 15 minutes to form a charge generation layer having a thickness of 0.17 μm.

  Next, 30 parts of a compound represented by the following structural formula (B) (charge transporting substance), 60 parts of a compound represented by the following structural formula (C) (charge transporting substance), and 10 of a compound represented by the following structural formula (D) Part, polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd., bisphenol Z-type polycarbonate), polycarbonate represented by the following structural formula (E) (viscosity average molecular weight Mv: 20000) 0.02 A coating solution for a charge transport layer was prepared by dissolving a part in a mixed solvent of 600 parts of mixed xylene and 200 parts of dimethoxymethane. The charge transport layer coating solution was dip coated on the charge generation layer to form a coating film, and the resulting coating film was dried at 100 ° C. for 30 minutes to form a charge transport layer having a thickness of 18 μm. .

  Next, a mixed solvent of 20 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolora H, Nippon Zeon Co., Ltd.) / 20 parts of 1-propanol was added to The mixture was filtered with a filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.). Thereafter, 90 parts of a hole transporting compound represented by the following structural formula (F),

  70 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane and 70 parts of 1-propanol were added to the mixed solvent. By filtering this with a polyflon filter (trade name: PF-020, manufactured by Advantech Toyo Co., Ltd.), a coating solution for a second charge transport layer (protective layer) was prepared. The coating solution for the second charge transport layer was dip-coated on the charge transport layer, and the obtained coating film was dried at 50 ° C. for 6 minutes in the air. Thereafter, in nitrogen, the coating film was irradiated with an electron beam for 1.6 seconds under the conditions of an acceleration voltage of 70 kV and an absorbed dose of 8000 Gy while rotating the support (object to be irradiated) at 200 rpm. Subsequently, the temperature was raised from 25 ° C. to 125 ° C. over 30 seconds in nitrogen, and the coating film was heated. The oxygen concentration in the atmosphere during electron beam irradiation and subsequent heating was 15 ppm. Next, a second charge transport layer (protective layer) having a thickness of 5 μm cured by an electron beam was formed by performing a heat treatment at 100 ° C. for 30 minutes in the air.

  In this manner, a workpiece (hereinafter referred to as a workpiece for simplicity) in which the photosensitive layer of the electrophotographic photosensitive member was formed on the cylindrical support was obtained.

(Formation of concave part by mold press-fit shape transfer)
In a press-fitting shape transfer processing apparatus having a configuration shown in FIG. 5, a mold having a shape shown in FIG. 7A as a mold was installed, and surface processing was performed on the manufactured workpiece. The shape of the convex part formed in the mold surface is shown below. Here, when the convex portion formed on the mold is viewed from above, the longest diameter is Xmax, the shortest diameter is Xmin, and the height of the convex portion is H. Further, the total ratio of the area occupied by the bottom area of the convex portion in the square area of 500 μm on one side of the mold surface is P here.
[Round convex bottom]
Xmax: 50 μm
Xmin: 50 μm
H: 3.0 μm
P: 50%
At the time of processing, the temperature of the workpiece and the mold was controlled so that the surface temperature of the workpiece was 120 ° C. Then, while pressing the electrophotographic photosensitive member and the pressure member at a pressure of 7.0 MPa, the electrophotographic photosensitive member is rotated in the circumferential direction to form a concave portion on the entire surface (peripheral surface) of the electrophotographic photosensitive member. did. This electrophotographic photosensitive member was designated as photosensitive member-D1.

(Observation of the surface of the electrophotographic photoreceptor)
The surface of the obtained electrophotographic photosensitive member (photosensitive member-D1) was magnified and observed with a 50 × lens with a laser microscope (trade name: X-100, manufactured by Keyence Corporation), and electrophotographic photosensitive as described above. Determination of the concave shape part provided in the surface of the body was performed.

  The observation location was selected as follows. In this example, the area where the cleaning blade abuts was an area from the central portion in the longitudinal direction of the electrophotographic photosensitive member to 160 mm toward both end portions of the electrophotographic photosensitive member. This area was divided into 10 equal parts in the longitudinal direction of the electrophotographic photosensitive member and 5 equal parts in the circumferential direction of the electrophotographic photosensitive member, and divided into 50 small areas. A square region having a side of 500 μm was taken at an arbitrary position in the small region, and the concave portion in the square region was observed.

  At the time of observation, adjustment was performed so that there is no inclination in the longitudinal direction of the electrophotographic photosensitive member, and the circumferential direction was focused on the apex of the arc of the electrophotographic photosensitive member. A square region having a side of 500 μm was obtained by connecting the enlarged images with an image connection application. Moreover, about the obtained result, image processing height data was selected with attached image analysis software, and the filter process was performed by the filter type median.

  Through the above observation, the longest opening portion diameter Rpc, the shortest opening portion diameter Lpc, the depth D, and the ratio s of the area occupied by the concave portion in the square region were determined. At this time, the concave portions transferred by the convex portions of the mold having the same shape confirm that the shapes and heights of the openings are the same for all the concave portions in the 50 square areas. did. Furthermore, the area ratio s of the concave portions in the 50 square areas was averaged to calculate the area ratio S of the concave portions in the photoconductor-D1. The results were as follows.

[Concave part with circular opening]
Rpc: 50 μm
Lpc: 50 μm
D: 2.0 μm
S: 50%

(Production Example-D2)
A photoconductor-D2 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. The surface of the photoconductor-D2 was observed in the same manner as in Production Example-D1. The results are shown in Table 1.

(Production Example-D3)
A mold having a shape generally shown in FIG. 7B was used as the mold. At this time, it was installed in the press-contact shape transfer processing apparatus so that the arrow described on the left side of (B) in FIG. 7 was parallel to the circumferential direction of the workpiece. Table 1 shows the shape of the protrusions formed on the surface of the mold. A photoconductor-D3 was produced in the same manner as in Production Example-D1, except that the mold was changed. The surface of the photoreceptor D3 was observed in the same manner as in Production Example-D1. The results are shown in Table 1.

(Production Example-D4)
A photoconductor-D4 was produced in the same manner as in Production Example-D3, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D3, the surface of Photoreceptor-D4 was observed. The results are shown in Table 1.

(Production Example-D5)
A photoconductor-D5 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D1, the surface of Photoconductor-D5 was observed. The results are shown in Table 1.

(Production Example-D6)
A photoconductor-D6 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D1, the surface of Photoreceptor-D6 was observed. The results are shown in Table 1.

(Production Example-D7)
A photoconductor-D7 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D1, the surface of Photoreceptor-D7 was observed. The results are shown in Table 1.

(Production Example-D8)
A photoconductor-D8 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D1, the surface of Photoreceptor-D8 was observed. The results are shown in Table 1.

(Production Example-D9)
A photoconductor-D9 was produced in the same manner as in Production Example-D1, except that the mold was changed as shown in Table 1. In the same manner as in Production Example-D1, the surface of Photoconductor-D9 was observed. The results are shown in Table 1.

(Comparative Production Example-d1)
Photoconductor-D10 was produced in the same manner as in Production Example-D1, except that the concave portion was not formed on the surface of the photoconductor.

(Comparative Production Example-d2)
In the same manner as in Production Example-D1, the second charge transport layer (protective layer) was formed. Next, using a dry blasting apparatus (manufactured by Fuji Seiki Manufacturing Co., Ltd.) shown in FIG.
Abrasive particles: spherical glass beads having an average particle size of 30 μm (trade name: UB-01L, manufactured by Union Co., Ltd.)
Compressed air blowing pressure: 0.343 MPa
Spray nozzle moving speed: 900 mm / min
Work rotation speed: 400rpm
The distance between the discharge port of the injection nozzle and the workpiece: 100 mm
Abrasive particle discharge angle: 90 °
Supply amount of abrasive particles: 200 g / min
Blasting frequency: One way × 2 times After dry blasting, the abrasive particles remaining on the surface of the photoconductor were removed by blowing compressed air to obtain photoconductor-D11.

  Concave portions with different shapes and areas of openings were formed on the surface of the photoconductor-D11 so as to overlap with each other, and concave portions independent of each other were not formed. Surface roughness was measured using a surface roughness measuring instrument (trade name: Surfcorder SE3500, manufactured by Kosaka Laboratory Ltd.), ten-point average roughness (Rzjis), uneven spacing (RSm) The maximum mountain height (Rp) and the maximum valley depth (Rv) were obtained. The results are shown below. Note that the measurement was performed along the direction of the generatrix of the photoconductor, and the measurement length was 0.4 mm and the measurement speed was 0.1 mm / s. Further, the baseline level setting value for noise cut at the time of measuring RSm was set to level setting = 10%.

In the present invention, ten-point average roughness (Rzjis), average interval of unevenness (RSm), maximum peak height (Rp), and maximum valley depth (Rv) were measured according to the method described in JIS-B0601-2001. Say.
Rzjis: 0.59 μm
RSm: 39 μm
Rp: 0.20 μm
Rv: 0.44 μm

<Manufacturing example of cleaning blade>
(Production Example-C1)
(Step of obtaining the first composition)
299 parts of 4,4′-diphenylmethane diisocyanate (hereinafter also referred to as “4,4′-MDI”) and 767.5 parts of butylene adipate polyester polyol (hereinafter also referred to as “BA2600”) having a number average molecular weight of 2600 are 80. The mixture was reacted at 0 ° C. for 3 hours to obtain a first composition (prepolymer) containing 7.2% by mass of NCO groups.

(Step of obtaining the second composition)
N, N, N′-trimethylaminoethylethanolamine (hereinafter also referred to as “ETA”) as a urethane rubber synthesis catalyst in 300 parts of hexylene adipate polyester polyol (hereinafter also referred to as “HA2000”) having a number average molecular weight of 2000 ) 0.25 part was added and stirred at 60 ° C. for 1 hour to obtain a second composition.

(Step of obtaining a mixture)
The first composition is heated to 80 ° C., the second composition heated to 60 ° C. is added thereto, and the mixture is stirred and mixed with the first composition and the second composition. Got. The number of moles of polyol in this mixture was 17 mol% based on the number of moles of polyisocyanate in the mixture. Hereinafter, this ratio is also expressed as “M (OH / NCO)”. In this example, M (OH / NCO) = 17 mol%.

(Process to obtain a cleaning blade made of urethane rubber)
A catalyst solution prepared by mixing 100 parts of ethanol with 100 parts of ethanol was spray-applied to one place on the inner surface of a mold for manufacturing a cleaning blade. Thereafter, the catalyst solution was wiped onto a part of the inner surface of the mold (surface corresponding to the contact portion of the cleaning blade) with a urethane rubber blade.

  Then, after heating the mold to 110 ° C., a release agent is applied to the inner surface of the mold where the catalyst solution is not applied, and the mold is heated again to 110 ° C. And stabilized.

  Thereafter, the mixture was injected into the mold (inside the cavity). After the injection, it was heated at 110 ° C. (molding temperature) for 30 minutes to cause a curing reaction, and then demolded to obtain a urethane rubber plate. The obtained urethane rubber plate was cut with a cutting machine to form an edge portion to obtain a cleaning blade made of urethane rubber. The resulting cleaning blade was 2 mm thick, 20 mm long, and 320 mm wide. This cleaning blade was designated as cleaning blade-C1. Production conditions and M (OH / NCO) are shown in Tables 2 and 3.

The cleaning blade -C1 obtained, by the method described above, was measured Young's modulus _{Y 0, Y 20, Y 50} . Furthermore, from these _{values, Y 50 / Y 0, Y} 20 / Y 0, ΔY 0-20, △ Y 20-50, was determined. The obtained results are shown in Table 4 and FIG.

In FIG. 9, a straight line connecting Young's modulus (Y ₀ ) and Young's modulus (Y ₅₀ ) is denoted as L _0-50, and a straight line connecting Young's modulus (Y ₀ ) and Young's modulus (Y ₂₀ ) is represented by L _{0. A} straight line connecting Young's modulus (Y ₂₀ ) and Young's modulus (Y ₅₀ ) was expressed as L _20-50 . It can be seen from the slopes of L _0-20 and L _20-50 that ΔY _0-20 ≧ ΔY _20-50 . Further, the Young's modulus (Y _N ) is lower than L _0-50 , and it can be seen that the profile of the change in Young's modulus when projecting from the surface of the contact portion toward the inside is convex downward.

Further, the cleaning blade-C1, was measured for IR spectrum by μATR method by the method described _above, it was determined a value of _I SI _/ I _SE. Table 4 shows the obtained results.

(Production Example-C2)
In Production Example-C1, 100 parts of ETA used for the preparation of the catalyst solution applied to the inner surface of the mold is represented by the following formula (D)

  (Product name: DABCO-TMR, Sankyo Air Products) 100 parts. Further, the molding temperature was changed from 110 ° C. to 80 ° C. Except for these, a cleaning blade -C2 was produced in the same manner as in Production Example-C1, and analytical measurement and physical property evaluation were performed. Production conditions and M (OH / NCO) are shown in Tables 2 and 3, and the results of analytical measurement and physical property evaluation are shown in Table 4.

(Production Example-C3)
In Production Example-C1, 100 parts of ETA used to prepare the catalyst solution to be applied to the inner surface of the mold was changed to 100 parts of a special amine (trade name: UCAT-18X, manufactured by San Apro Co., Ltd.). Also, the molding temperature was changed from 110 ° C to 150 ° C. Except for these, cleaning blade-C3 was produced in the same manner as in Production Example-C1, and analytical measurements and physical property evaluations were performed. Production conditions and M (OH / NCO) are shown in Tables 2 and 3, and the results of analytical measurement and physical property evaluation are shown in Table 4.

(Production Example-C4)
In Production Example-C1, the amount of HA2000 in the step of obtaining the second composition was changed from 300 parts to 360 parts. Further, 100 parts of ETA used for the preparation of the catalyst solution applied to the inner surface of the mold was changed to 100 parts of CH ₃ COOK (trade name: POLYCAT46, manufactured by Air Products). Except for these, cleaning blade-C4 was produced in the same manner as in Production Example-C1, and analytical measurements and physical property evaluations were performed. Production conditions and M (OH / NCO) are shown in Tables 2 and 3, and the results of analytical measurement and physical property evaluation are shown in Table 4.

(Production Example-C5)
In Production Example-C1, the amount of HA2000 in the step of obtaining the second composition was changed from 300 parts to 218.5 parts. Moreover, 100 parts of ETA used for the preparation of the catalyst solution applied to the inner surface of the mold was changed to 100 parts of UCAT-18X (trade name). Further, the molding temperature was changed from 110 ° C. to 100 ° C. Except for these, cleaning blade-C5 was produced in the same manner as in Production Example-C1, and analytical measurements and physical property evaluations were performed. Production conditions and M (OH / NCO) M (OH / NCO) are shown in Tables 2 and 3, and the results of analytical measurement and physical property evaluation are shown in Table 4.

(Comparative Production Example-c1)
In Production Example-C1, the amount of HA2000 in the step of obtaining the second composition was changed from 300 parts to 500 parts. The molding temperature was changed from 110 ° C to 140 ° C. Except for these, cleaning blade-C6 was produced in the same manner as in Production Example-C1, and analytical measurement and physical property evaluation were performed. Production conditions and M (OH / NCO) M (OH / NCO) are shown in Tables 2 and 3, and the results of analytical measurement and physical property evaluation are shown in Table 4.

Example 1
The following evaluation was performed using the photoreceptor-D1 and the cleaning blade-C1.

(Evaluation of H / H initial streak)
A copying machine manufactured by Canon Inc. (trade name: iR-ADVC5255) was used as an evaluation machine. Photoreceptor-D1 and cleaning blade-C5 were mounted on the cyan station of the copying machine. The cleaning blade-C5 was installed such that its contact surface (the surface facing the surface on which the catalyst solution was applied on the inner surface of the mold) was contacted with the photoconductor-D1 in a counter manner. The installation conditions were a set angle of 22 °, a contact pressure of 28 gf / cm, and a free length of 8 mm.

The conditions of the charging device and the image exposure device are set so that the dark portion potential (Vd) of the photoreceptor is −500 V and the light portion potential (Vl) is −180 V in a high temperature and high humidity environment of 30 ° C./80% RH. The initial potential of the photoconductor was adjusted. With the heater for the photoconductor (drum heater) turned on, 200 evaluation charts for the 1% printed image next to A4 are output continuously, and then a screen image with a cyan density of 30% is output as a halftone image. The H / H initial streak on the image was evaluated as follows. The results are shown in Table 5.
A: No streak is generated on the image.
B: An image where a streak is suspected is obtained on the image, but it is a level at which it cannot be clearly determined whether or not it is a streak.
C: Slightly slight streaks can be confirmed on the image, but there is no problem on the image.
D: A slight streak is generated on the image, but this is an acceptable level on the image.
E: A clear streak is generated on the image. This is an unacceptable level on the image.

(Shock stripe evaluation)
A copying machine manufactured by Canon Inc. (trade name: iR-ADVC5255) was used as an evaluation machine. The peripheral speed of the photosensitive member was set to 250 mm / sec. The peripheral speed of the intermediate transfer belt was set to 255 mm / sec.

  Photoreceptor-D1 and cleaning blade-C5 were mounted on the black station of the copying machine. The cleaning blade-C5 was installed such that its contact surface (the surface facing the surface on which the catalyst solution was applied on the inner surface of the mold) was contacted with the photoconductor-D1 in a counter manner. The installation conditions were a set angle of 22 °, a contact pressure of 28 gf / cm, and a free length of 8 mm.

The conditions of the charging device and the image exposure device are set so that the dark portion potential (Vd) of the photoreceptor is −500 V and the light portion potential (Vl) is −180 V in a high temperature and high humidity environment of 30 ° C./80% RH. The initial potential of the photoconductor was adjusted. The printing mode was set to the black monochrome printing mode, a screen image having a black density of 30% was output as a halftone image on A3 vertical paper, and shock streaks on the image were evaluated as follows. The results are shown in Table 5.
A: No streak is generated on the image.
B: Very slight streaks are generated on the image.
C: Although slight streaks are generated on the image, the level is acceptable on the image.
D: A clear streak of an unacceptable level is generated on the image.

(Example 2)
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D2 and the cleaning blade-C2 were used. The results are shown in Table 5.

(Example 3)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D3 and the cleaning blade-C3 were used. The results are shown in Table 5.

Example 4
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D1 and the cleaning blade-C2 were used. The results are shown in Table 5.

(Example 5)
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D3 and the cleaning blade-C2 were used. The results are shown in Table 5.

(Example 6)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D1 and the cleaning blade-C3 were used. The results are shown in Table 5.

(Example 7)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D2 and the cleaning blade-C3 were used. The results are shown in Table 5.

(Example 8)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D1 and the cleaning blade-C4 were used. The results are shown in Table 5.

Example 9
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D2 and the cleaning blade-C4 were used. The results are shown in Table 5.

(Example 10)
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D3 and the cleaning blade-C4 were used. The results are shown in Table 5.

(Example 11)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D1 and the cleaning blade-C5 were used. The results are shown in Table 5.

(Example 12)
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D2 and the cleaning blade-C5 were used. The results are shown in Table 5.

(Example 13)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D4 and the cleaning blade-C5 were used. The results are shown in Table 5.

(Example 14)
Evaluation was performed in the same manner as in Example 1 except that the photoconductor-D5 and the cleaning blade-C5 were used. The results are shown in Table 5.

(Example 15)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D6 and the cleaning blade-C5 were used. The results are shown in Table 5.

(Example 16)
Evaluation was carried out in the same manner as in Example 1 except that Photoreceptor-D7 and Cleaning Blade-C5 were used. The results are shown in Table 5.

(Example 17)
Evaluation was carried out in the same manner as in Example 1 except that Photoreceptor-D8 and Cleaning Blade-C5 were used. The results are shown in Table 5.

(Example 18)
Evaluation was performed in the same manner as in Example 1 except that Photoreceptor-D9 and Cleaning Blade-C5 were used. The results are shown in Table 5.

(Comparative Example 1)
Evaluation was performed in the same manner as in Example 1 except that the photoreceptor-D1 and the cleaning blade-C6 were used. The results are shown in Table 5.

(Comparative Example 2)
Evaluation was performed in the same manner as in Example 1 except that Photoreceptor-D10 and Cleaning Blade-C5 were used. The results are shown in Table 5.

(Comparative Example 3)
Evaluation was performed in the same manner as in Example 1 except that Photoreceptor-D11 and Cleaning Blade-C5 were used. The results are shown in Table 5.

  From Table 5, it can be seen that in Examples 1 to 18, both the H / H initial stripe and the shock stripe are improved. On the other hand, it can be seen from Comparative Example 1 that a cleaning blade that does not satisfy the requirements of the present invention causes a problem of H / H initial streaks. In addition, it can be seen from Comparative Examples 2 and 3 that problems may occur with shock stripes in electrophotographic photoreceptors that do not satisfy the requirements of the present invention.

Claims (10)

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, an intermediate transfer unit, a primary transfer unit, a secondary transfer unit and a cleaning unit for an electrophotographic photosensitive unit,
The electrophotographic photosensitive member has a cleaning blade made of urethane rubber, and the cleaning blade is brought into contact with the surface of the electrophotographic photosensitive member to clean the surface of the electrophotographic photosensitive member. Cleaning means,
In the cleaning blade, the Young's modulus (Y ₀ ) of the surface C of the contact portion with the electrophotographic photosensitive member is 10 mgf / μm ² or more and 400 mgf / μm ² or less,
The ratio (Y ₅₀ / Y ₀ ) between the Young's modulus (Y ₅₀ ) and the Young's modulus (Y ₀ ) at a position inside 50 μm from the surface C is 0.5 or less,
When the Young's modulus at a position inside 20 μm from the surface C is defined as (Y ₂₀ ), the average change rate of Young's modulus from the surface C to the position inside 20 μm [{(Y ₀ −Y ₂₀ ) / Y ₀ } / (20-0)] is equal to or greater than the average rate of change of Young's modulus from the position inside 20 μm to the position inside 50 μm [{(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20)]. Yes,
A plurality of concave portions are formed on the surface of the electrophotographic photosensitive member,
The ratio of the area occupied by the concave portion on the entire surface where the electrophotographic photosensitive member and the cleaning blade come into contact is 30% or more and 70% or less,
An electrophotographic apparatus, wherein the concave portion has a depth of 0.5 μm or more and 3.0 μm or less, an opening longest diameter of 20 μm or more and 100 μm or less, and an opening shortest diameter of 20 μm or more and 100 μm or less.   2. The intermediate transfer member is a belt-like intermediate transfer member, and the ratio of the area occupied by the concave portion on the entire surface where the electrophotographic photosensitive member and the cleaning blade come into contact is 50% or more and 70% or less. The electrophotographic apparatus described in 1.   The electrophotographic apparatus according to claim 1, wherein a depth of the concave portion formed on the surface of the electrophotographic photosensitive member is 0.5 μm or more and 2.0 μm or less.   The electrophotographic apparatus according to claim 1, wherein a longest diameter of the concave portion formed on the surface of the electrophotographic photosensitive member is 50 μm or more and 100 μm or less. 5. The electrophotographic apparatus according to claim 1, wherein the Young's modulus (Y ₀ ) of the cleaning blade is 10 mgf / μm ² or more and 250 mgf / μm ² or less.   The electrophotographic apparatus according to claim 1, wherein the urethane rubber of the cleaning blade is a polyester urethane rubber containing an isocyanurate group. When the urethane rubber of the cleaning blade is a polyester urethane rubber containing an isocyanurate group and the IR spectrum is measured by the μATR method on the surface of the polyester urethane rubber in the contact portion, the polyester urethane Strength (I _SI ) of C—N peak (1411 cm ⁻¹ ) derived from isocyanurate groups in rubber and strength (I _SE ) of C═O peak (1726 cm ⁻¹ ) derived from ester groups in the polyester-based urethane rubber The electrophotographic apparatus according to claim 1, wherein a ratio (I _SI / I _SE ) to 0.51 is 1.50 or more and 1.55 or less. The electrophotographic apparatus according to claim 7, wherein the ratio (I _SI / I _SE ) is 1.35 or less. The electrophotographic apparatus according to claim 1, wherein the Young's modulus (Y ₀ ) is 344 mgf / μm ² or less. The electrophotographic apparatus according to claim 9, wherein the Young's modulus (Y ₀ ) is 250 mgf / μm ² or less.