JP2005164775A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which ensures high image quality, high durability and a long lifetime and does not cause curl of a cleaning blade or defects in image formation due to lowering of cleaning performance, such as escape of toner and image deletion even when a surface of a high durability photoreceptor having high hardness and high elasticity is cleaned in a low temperature or high humidity environment. <P>SOLUTION: The image forming apparatus has a fatty acid metal salt supplying means to supply a fatty acid metal salt to a surface of an electrophotographic photoreceptor having an HU (universal hardness) of 150-220 N/mm<SP>2</SP>and an elastic deformation ratio Wo of 44-65%, wherein a rubber hardness of the cleaning blade is 78-99°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming apparatus. More specifically, the electrophotographic photosensitive member, the charging means for charging the photosensitive member, the information writing means for forming an electrostatic latent image on the charging surface of the photosensitive member, and the developer carried on the developer carrying member, An image having a developing unit that develops the electrostatic latent image as a toner image, a transfer unit that transfers the toner image on the photosensitive member to a transfer member, and a cleaning unit that collects residual toner particles on the surface of the photosensitive member after the toner image is transferred. The present invention relates to a forming apparatus.

  In an image forming method used for an electrophotographic apparatus, an electrostatic recording apparatus, and the like, various methods are known as a method for forming a latent image on a photosensitive member such as an electrophotographic photosensitive member or an electrostatic recording dielectric.

  For example, in electrophotography, an electrical latent image is formed by uniformly charging a photoconductor using a photoconductive material as a latent photoconductor to the required polarity and potential, and then performing image pattern exposure. In general, the toner is developed and visualized, and this is transferred and fixed to a transfer medium such as paper.

  Conventionally, in this type of image forming method, by providing a protective layer on the outermost surface layer, an electrophotographic photosensitive member that has excellent durability against wear and scratches and can maintain high quality image quality. The thing using a body is proposed (for example, refer to patent documents 1 and patent documents 2).

  In particular, a photoreceptor having a protective layer made of a curable resin can increase elasticity while maintaining a large HU (Universal Hardness Value). This type of photoreceptor having both rigidity and elasticity is strong against abrasion and has high durability. In such an image forming method using a photoconductor, since it is resistant to rubbing with a cleaning blade or the like, the durable life and potential change of the photoconductor can be suppressed, and stable image output performance can be obtained over a long period of time.

  On the other hand, in an electrophotographic image forming method, it is known that discharge products due to various charges such as NOx, SOx, ozone, and the like are generated by the charging energy when charging a photoreceptor. These discharge products adhere to the photoreceptor and cause the slippage of the photoreceptor surface to deteriorate. For this reason, a frictional force is increased between the cleaning blade in contact with the photosensitive member and the photosensitive member, causing the photosensitive member driving torque to be increased, drooping, and blade chatter (vibration), leading to defective cleaning.

  In particular, when using a highly durable photoreceptor that is difficult to scrape as described above, the surface of the photoreceptor is difficult to be refreshed, and surface chargeable organisms are likely to adhere and accumulate, so that the initial slipperiness is good. However, cleaning may fail due to repeated image formation. In particular, even when the plastic deformation is small, the total deformation amount is large, that is, in the case of a highly durable photoreceptor having a rubber behavior, the friction with the cleaning blade is particularly large. As a result, blades and drums are easily broken, and the durability life is shortened in that respect. Furthermore, in a high temperature environment, the blade hardness is soft due to the temperature characteristics of the cleaning blade, and serious problems such as turning over the cleaning blade are likely to occur.

  In contrast, by providing means for supplying the fatty acid metal salt to the surface of the photoreceptor, the fatty acid metal salt is interposed between the cleaning blade and the surface of the photoreceptor, and the cleaning blade or the drum is destroyed due to deterioration of slipperiness at the cleaning portion. -The thing which suppresses deterioration is proposed (for example, patent document 3).

  There is also a method of preventing blade breakage and turning by increasing the rubber hardness of the cleaning blade. Furthermore, it is possible to prevent the cleaning blade from being destroyed or turned up by improving the sliding property of the cleaning blade itself. An isocyanate compound is used to form a hardened layer on the surface of the cleaning blade, to reduce the coefficient of friction on the surface of the cleaning blade, and to improve the altitude. For example, the surface of the cleaning blade is treated with an isocyanate compound, that is, the isocyanate compound is reacted with moisture in the air or the polyurethane resin itself on the surface of the polyurethane resin, so that the surface of the polyurethane resin is 0.01 to 0.00. It has been proposed to form a 6 mm cured thin film (see, for example, Patent Document 4 and Patent Document 5).

Further, a method has been proposed in which a hardened layer is formed only on the blade edge portion to maintain the blade free length motility, while reducing the coefficient of friction to obtain good cleaning performance (see, for example, Patent Document 6). ).
JP 05-181299 A JP 2002-084469 A JP 2001-265040 A Japanese Utility Model Publication No. 57-178262 Japanese Patent Laid-Open No. 08-248851 JP 2001-343874 A

  However, in cleaning a photoconductor having an elastic deformation rate Wo of 44% or more and 65% or less on the surface of the photoconductor, the cleaning blade vibration is stabilized by attaching a fatty acid metal salt to the surface of the photoconductor to improve the cleaning performance. In this case, the toner easily slips through with the fatty acid metal salt particularly in a low humidity environment, which affects the output image. Furthermore, in a high humidity environment, the lubrication performance and the effect of suppressing image blur due to the protective film of the fatty acid metal salt could not be obtained sufficiently.

  Further, if the blade rubber hardness is increased to improve the scraping ability and durability of the blade, the edge does not follow the elastic deformation of the photosensitive member and chatter occurs, and the toner is easily removed.

  Accordingly, an object of the present invention is to provide a high image quality, high durability, and long service life that does not cause defective image formation due to a decrease in cleaning performance due to environmental changes as described above when cleaning the surface of a highly durable photoconductor having high hardness and high elasticity. An image forming apparatus is provided.

  In order to achieve the above object, the present invention is an image forming apparatus having the following configurations (1) to (7).

(1) A hardness test was performed using a Vickers square pyramid diamond indenter in an environment of 25 ° C. and 50% humidity, and the HU (universal hardness value) when pressed at a maximum load of 6 mN was 150 N / mm ² or more and 220 N / mm ² And an electrophotographic photosensitive member having a surface with an elastic deformation rate Wo of 44% or more and 65% or less, a means for forming a latent image on the photosensitive member, and a developing means for developing the latent image with toner And a transfer unit that transfers the developed toner to a transfer material, and a cleaning unit that removes toner remaining on the photoconductor after the transfer with a cleaning blade. An image forming apparatus having a fatty acid metal salt supply means for supplying and having a cleaning blade having a rubber hardness of 78 degrees to 99 degrees.

  (2) The image forming apparatus according to (1), wherein the cleaning blade has a dynamic friction coefficient of 0.2 or more and 1.2 or less with respect to the PET sheet.

  (3) The image forming apparatus according to (1) or (2), wherein the concentration of the isocyanate group in the surface portion of the cleaning blade in contact with the photosensitive member is greater than the concentration of the isocyanate group in the blade.

(4) When the rubber hardness of the cleaning blade is H, the following formula H / Wo <2
The image forming apparatus according to any one of (1) to (3), wherein:

  (5) The photoreceptor has a protective layer, and the protective layer is at least a group selected from the group consisting of a curable phenol resin and a hydroxyalkyl group, a hydroxyalkoxy group, or a hydroxyphenyl group which may have a substituent. The image forming apparatus according to any one of the above (1) to (4), comprising a charge transport material having one.

  (6) The image forming apparatus according to any one of (1) to (5), wherein the fatty acid metal salt coating unit also serves as the developing unit.

  (7) The image forming apparatus according to any one of (1) to (5), wherein the fatty acid metal salt coating unit also serves as a cleaning auxiliary unit provided upstream of the cleaning unit.

As a result of intensive studies by the present inventors, a hardness test was conducted using a Vickers square pyramid diamond indenter in an environment with a surface of 25 ° C. and a humidity of 50%, and the HU (Universal Hardness Value) when pressed at a maximum load of 6 mN. An image forming apparatus having an electrophotographic photosensitive member having a high durability of 150 N / mm ² or more and 220 N / mm ² or less and having an elastic deformation rate Wo of 44% or more and 65% or less is configured as described above. For example, it has been found that good cleaning performance is exhibited even in a low or high humidity environment.

  According to the first aspect of the present invention, there is provided a means for supplying a fatty acid metal salt to the surface of the photoreceptor, and if the rubber hardness of the cleaning blade is 78 degrees or more and 99 degrees or less, By providing sufficient adhesion on the surface of the photoconductor, chattering between the high-elasticity and high-hardness photoconductor and the blade with high rubber hardness is suppressed, and the peak value of the pressure distribution at the contact area of the photoconductor with the blade with higher rubber hardness As a result, it becomes easier to scrape transfer residual toner and discharge product deposits together with the fatty acid metal salt film on the surface of the photosensitive member, and the cleaning property of the surface of the photosensitive member with high elasticity and high hardness is greatly improved.

  Regarding the invention of claim 2, in addition to the above invention, if the dynamic friction coefficient of the cleaning blade to the PET sheet is 0.2 or more and 1.2 or less, the slipperiness becomes appropriate when the fatty acid metal salt coats the surface of the photoreceptor. The fatty acid metal salt on the photoreceptor can achieve both the durability of the cleaning blade and the cleaning property of the toner.

  With respect to the invention of claim 3, in addition to the above invention, if the concentration of the isocyanate group in the surface portion of the cleaning blade in contact with the photosensitive member is larger than the concentration of the isocyanate group inside the blade, Since the function can be separated in terms of the sliding property of the blade surface, the friction coefficient can be lowered while maintaining the cleaning performance.

In the invention of claim 4, when the rubber hardness of the cleaning blade is H, the following formula H / Wo <2
By satisfying the above, squeal due to blade friction can be prevented. Although the details of the mechanism are not clear in this regard, both the high elastic deformation rate photoconductor and the high rubber hardness cleaning blade can be considered as a firm spring, and in particular, the vibration of the photoconductor is not generated or absorbed as much as possible. It is considered that proper vibration generation prevention / absorption is performed within the above formula range.

As described above, according to the present invention, a fatty acid metal salt is supplied to the surface of the photoreceptor, and a cleaning blade having a rubber hardness of 78 degrees or more and 99 degrees or less is used. (Hardness value) is 150 N / mm ² or more and 220 N / mm ² or less and the elastic deformation rate Wo is 44% or more and 65% or less, stabilizing the cleaning blade in contact with the photosensitive member, and good cleaning To achieve long-life and high-quality image formation.

<Image forming process>
FIG. 1 shows an example of an image forming apparatus according to the present invention. FIG. 2 is a longitudinal sectional view showing a schematic configuration of a digital copying machine. The copying machine shown in the figure includes a drum-type electrophotographic photosensitive member 101 as a photosensitive member. The photosensitive member 101 is rotationally driven in the direction of an arrow by a driving unit (not shown). Around the photosensitive member 101, a charging roller 102, which is a primary charging unit, an exposure unit 103, a developing unit (developing unit) 104, and a transfer charging unit (transfer unit) 105 are arranged almost sequentially along the rotation direction. ing. Further, a fixing device 106 is disposed on the downstream side (left side in the figure) of the transfer charger 105 in the conveyance direction (arrow direction) of the transfer material 111. The surface of the photoreceptor 101 is uniformly charged by the primary charger 102. Next, image exposure is performed by the laser beam emitted from the exposure means 103, the electric charge of the laser beam irradiated portion is removed, and an electrostatic latent image is formed. The electrostatic latent image on the photoconductor 101 is developed with the charged toner of the developing device 104. The developed toner image on the photoreceptor 101 is transferred by the transfer charger 105 to the transfer material 111 conveyed in the direction of the arrow. After the toner image is transferred, the transfer material 111 is conveyed to a fixing device 106 where the toner image is fixed on the surface by being heated and pressurized. The untransferred toner remaining on the photosensitive member 101 after the transfer is collected and removed by an elastic cleaning blade that is in contact with the counter of the drum of the cleaning device 107.

  The cleaning device 107 is a means for collecting and cleaning the transfer residual toner remaining on the photoconductor 101 after the toner transfer. In the present invention, the toner on the photosensitive member is cleaned by bringing an elastic blade mainly made of polyurethane rubber into contact with the rotation of the photosensitive member with a counter as shown in FIG. The toner and lubricant scraped off by the cleaning blade are received by a scooping sheet and sent to a waste toner box by a toner feed blade, a brush roller, a screw and the like.

<Fatty acid metal salt>
The fatty acid metal salt easily forms a film on the surface of the photoreceptor, and is interposed between the cleaning blade and the photoreceptor by appropriate supply to the surface of the photoreceptor, and plays a role of assisting in cleaning.

  Fatty acid calcium salt is particularly preferably used from the viewpoint of preventing blade wear and photoreceptor wear. Specific examples of fatty acid calcium salts include calcium undecylate, calcium laurate, calcium tridecylate, calcium dodecylate, calcium myristate, calcium palmitate, calcium pentadecylate, calcium stearate, calcium behenate, calcium heptadecylate, calcium arachidate Long chain fatty acid calcium such as calcium montanate, calcium oleate, calcium linoleate, calcium arachidate and calcium behenate, and calcium stearate is particularly preferred. The fatty acid component is a single or mixed fatty acid. Other specific fatty acid metal salts include zinc stearate, zinc laurate, strontium stearate, strontium laurate, barium stearate, barium laurate and the like. A monovalent metal is liable to be deteriorated by discharge such as charging, and is liable to cause an image flow.

  The free fatty acid content of the fatty acid metal salt is preferably 0.01 to 2.0% by mass, particularly preferably 0.05 to 1.0% by mass. When the amount is more than 2.0% by mass, the developer, the developing roller, and the charging member are contaminated or firmly adhered to the surface of the photosensitive member, leading to turning of the blade and image flow. If too little, the blade wear tends to increase rather, and the life of the cleaning blade may be shortened.

  The method of supplying to the photosensitive member is to contact a fur brush roller, which is a cleaning aid, which is formed by solidifying a fatty acid metal salt, scraping it off by rotation of the fur brush roller and supplying it to the photosensitive member, or externally adding to the toner and so on.

<Cleaning blade>
Of various physical properties that determine the characteristics of the cleaning blade, the hardness and friction coefficient according to the present invention will be described.

  Generally, when the hardness of the cleaning blade is high, the photoconductor is worn or damaged, and when the hardness is low, the wear or damage of the rubbing portion (edge portion) with the surface of the photoconductor of the cleaning blade is increased. Therefore, conventionally, the hardness is set to an appropriate value in consideration of various conditions shown below. The appropriate range of the hardness of the cleaning blade varies depending on the hardness of the photoconductor used, the type of toner, or the configuration of the image forming apparatus. For example, when the toner includes magnetic powder, the appropriate range of hardness of the cleaning blade is higher than when the toner does not include magnetic powder. Further, when talc is detached from the paper to be used, an appropriate range of hardness of the cleaning blade is increased in order to remove talc that has detached from the paper and adhered to the surface of the photosensitive member from the surface of the photosensitive member. In addition, the hardness of the blade in this invention is Hs rubber hardness in a JIS-A scale.

  If the friction coefficient is high, the life of the cleaning blade and the photosensitive member is shortened, so that it is necessary to reduce the friction coefficient. Further, if the friction coefficient is too small, it is disadvantageous for toner slipping. By adding a lubricant to the surface of the photoreceptor or modifying the surface of the cleaning blade, the friction coefficient can be suppressed within an appropriate range. The friction coefficient in the present invention is a dynamic friction coefficient, and the dynamic friction coefficient (μ) of the cleaning blade is measured with a surface tester (model HEIDON-14) manufactured by HEIDON. The blade is pressed against a polyethylene terephthalate (PET) sheet with a constant load (g), and the force applied while moving parallel to the PET sheet surface is measured. The dynamic friction coefficient in the present invention is obtained by {force applied to the PET sheet (g)} / {load applied to the blade (g)} when the blade is moving. The blade was measured at a load of 20 to 100 g / cm and a contact angle of 22.5 °. A schematic sectional view of the cleaning blade fixing device is shown in FIG. The coefficient of dynamic friction is measured by a device (not shown) that moves the PET sheet 201 in parallel after the cleaning blade 202 fixed by the cleaning blade fixing member 203 connected to the detection unit of the surface testing machine main body is brought into contact with the PET sheet 201. And moving in the direction of the arrow to detect the force applied to the PET sheet 201. When the detected data of the dynamic friction coefficient fluctuates, an average value is taken.

<Modification by surface treatment of cleaning blade>
An isocyanate compound is used to form a hardened layer on the surface of the cleaning blade, to reduce the coefficient of friction on the surface of the cleaning blade, and to improve the altitude.

  The cured layer in the present invention is formed by impregnating the surface of a cleaning blade made of polyurethane resin with at least an isocyanate compound for a predetermined time without impregnating with an active hydrogen compound, and then reacting the isocyanate compound with the polyurethane resin. The That is, the polyurethane resin forming the cleaning blade has a urethane bond having active hydrogen, and in the present invention, the urethane bond is reacted with the impregnated isocyanate compound to form an allophanate bond. A layer is created. In addition, it is considered that the multimerization reaction of the isocyanate compound proceeds simultaneously and contributes to the formation of the cured layer.

  In this case, since the active hydrogen compound is not impregnated, a cured thin film is not formed in the vicinity of the surface of the cleaning blade, and the isocyanate compound penetrates deep enough to form a cured layer having a sufficient thickness. As a result, the friction coefficient on the surface of the cleaning blade is sufficiently reduced, the hardness is sufficiently improved, and the durability of the cleaning blade can be improved. Even if the surface of the cleaning blade is worn, the hardened layer is thick, so that the good characteristics of the surface of the cleaning blade are maintained for a long time.

  Here, the active hydrogen compound means a compound containing a reactive group having a hydrogen which reacts with the isocyanate group of the isocyanate compound and participates in urethane bond formation. For example, polyols, polyamines, alkanolamines. Meaning polycarboxylic acids and the like.

  Further, the isocyanate group content (NCO%) of the polyurethane resin is preferably 5% or more and 20% or less in order to realize good elastic properties.

  As the prepolymer or semi-prepolymer which is a raw material of the urethane resin, a product obtained by reacting a polymer polyol, a polyisocyanate and a crosslinking agent as an active hydrogen compound can be used.

  Specific examples of the polymer polyol as the active hydrogen compound include polyester polyols, polyether polyols, caprolactone ester polyols, polycarbonate ester polyols, silicone polyols, and the like. These weight average molecular weights are usually 500 or more and 5000 or less. is there.

Specific examples of the polyisocyanate include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), and the like.
In the semi-prepolymer method, the polymer polyol is mixed with a crosslinking agent.

  In addition, isocyanate group content (NCO%) is the mass% of the isocyanate functional group (NCO, molecular weight is calculated as 42) contained in 100 g of prepolymers or semi-prepolymers that are raw materials for urethane resins.

  Specific examples of the crosslinking agent include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, trimethylolpropane and the like.

  In addition, when making high molecular polyol, polyisocyanate, and a crosslinking agent react, the normal catalyst used for formation of a polyurethane resin may be added. Specific examples of such a catalyst include triethylenediamine.

  As a molding method of the cleaning blade before forming the hardened layer, a one-shot method in which polymer polyol, polyisocyanate, cross-linking agent, catalyst, etc. are mixed at once and cast into a mold or a centrifugal molded cylindrical mold. A prepolymer method in which a high-molecular polyol and a polyisocyanate are pre-reacted to form a prepolymer, and then a cross-linking agent, a catalyst, and the like are mixed and cast into a mold or a centrifugal molded cylindrical mold; Examples include a semi-one-shot method in which a semi-prepolymer reacted with a molecular polyol is reacted with a curing agent obtained by adding a polymer polyol to a cross-linking agent, and cast into a mold or a centrifugal molded cylindrical mold. Can do.

  The isocyanate compound impregnated in the polyurethane resin in this blade manufacturing method has one or more isocyanate groups in the molecule.

  Examples of the isocyanate compound having one isocyanate group include aliphatic monoisocyanates such as octadecyl isocyanate (ODI), aromatic monoisocyanates, and the like.

  When the isocyanate group of an isocyanate compound having one isocyanate group as described above reacts with a urethane group to form an allophanate bond, the end of the isocyanate compound where the isocyanate group does not exist is oriented toward the surface of the cleaning blade. The direct contact between the unreacted polyurethane resin and the toner carrier is suppressed, and the friction coefficient is reduced.

  Examples of isocyanate compounds having two isocyanate groups include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), m-phenylene diisocyanate, tetramethylene diisocyanate, hexa Examples include methylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, 2,4 ′, 4 ″ -biphenyl triisocyanate, and 2,4,4 ″ -diphenylmethane triisocyanate.

  In addition, isocyanate compounds having 3 or more isocyanate groups, derivatives, modified products, multimers, etc. of isocyanate compounds having 2 or more isocyanate groups can also be used.

  When the polyurethane resin is impregnated with an isocyanate compound having two or more isocyanate groups and reacted with the polyurethane resin, the active hydrogen compound is not impregnated in the present invention. Therefore, an excess isocyanate compound that does not react with the polyurethane resin forms a self-polymer. It produces or reacts with water in the environment to produce a polymer having a urea bond. For this reason, in addition to the crosslinked structure comprising an isocyanate compound and a polyurethane resin, a network structure comprising an isocyanate compound polymer is further formed in the cured layer. As a result, the durability of the cured layer is further improved.

  Among the isocyanate compounds exemplified above, an aliphatic isocyanate compound having a small steric hindrance and an isocyanate compound having a small molecular weight are excellent in permeability, so that the thickness of the resulting cured layer can be easily controlled. On the other hand, since the isocyanate compound having a large molecular weight is inferior in permeability but is a long chain, the molecular chain protrudes from the surface of the cured layer after forming the cured layer, and the friction coefficient is effectively reduced.

  In order to accelerate the polymerization reaction of the isocyanate compound, the polyurethane resin may be impregnated with a polymerization catalyst of the isocyanate compound in addition to the isocyanate compound.

  For example, together with the isocyanate compound, a polyurethane resin is impregnated with a polymerization catalyst of the isocyanate compound for a predetermined time.

  Examples of the polymerization catalyst used together with the isocyanate compound include a quaternary ammonium salt and a carboxylate. Examples of the quaternary ammonium salt include DABCO TMR catalyst, NCX211 (Sankyo Air Products), NCX212 (Sankyo Air Products) and the like. Although these polymerization catalysts contain a hydroxyl group, the function of the polymerization catalyst is to polymerize the isocyanate compound, and does not participate in the crosslinked structure itself, and is different from the active hydrogen compound in the present invention. Examples of the carboxylate include potassium acetate and potassium octylate such as P-15 and k-15 manufactured by Sankyo Air Products.

  Since these polymerization catalysts are very viscous or solid at the time of impregnation, they are preferably dissolved in a solvent in advance and then added to an isocyanate compound and impregnated in a polyurethane resin. As the solvent, those having no active hydrogen capable of reacting with an isocyanate compound are used, and specific examples include MEK, toluene, tetrahydrofuran, ethyl acetate and the like. The dilution ratio is preferably 1.5 to 15 times in terms of mass ratio. Moreover, the addition rate of the polymerization catalyst with respect to the isocyanate compound is preferably 1 ppm by mass or more and 1000 ppm by mass or less at the final concentration. In addition, since a polymerization reaction is started when an isocyanate compound and a polymerization catalyst are mixed, the mixing of the isocyanate compound and the polymerization catalyst is preferably performed immediately before impregnation of the isocyanate compound.

  When the cleaning blade is impregnated with the isocyanate compound, the cleaning blade may be in a single state or may be bonded to the support member. Alternatively, the sheet before cutting the cleaning blade may be impregnated with the isocyanate compound and reacted, and then the sheet may be cut to form a cleaning blade.

  The region of the cleaning blade impregnated with the isocyanate compound includes at least an end portion where the cleaning blade and the toner carrier are in contact with each other.

  The impregnation of the cleaning blade with the isocyanate compound is performed, for example, by immersing the cleaning blade in the liquid of the isocyanate compound at a temperature at which the isocyanate compound is a liquid. That is, only a predetermined region of the toner carrier contact portion is immersed in a bath that does not contain an active hydrogen compound and is mainly made of an isocyanate compound for a predetermined time.

  Moreover, a method of impregnating a fibrous member or a porous member with an isocyanate compound and applying it to a cleaning blade, or a method of applying by spraying can also be exemplified.

  In addition, as a method of impregnating only the contact portion of the cleaning blade with the isocyanate compound, masking a portion that is not desired to be impregnated with a chemical resistant tape or the like can be exemplified. That is, a mask member is disposed on the surface of the cleaning blade so that only a predetermined region of the toner carrier contact portion is exposed, and only the surface of the portion where the mask member is not disposed is impregnated with the active hydrogen compound. Then, at least an isocyanate compound is impregnated for a predetermined time.

  As described above, the isocyanate compound is impregnated in the cleaning blade for a predetermined time, and then the isocyanate compound remaining on the surface of the cleaning blade is wiped off. Then, the reaction between the impregnated isocyanate compound and the polyurethane resin is allowed to proceed.

  In order to make the thickness of the cured layer of the finally obtained cleaning blade within a desired range, the impregnation time of the isocyanate compound is preferably 6 minutes or more, more preferably 8 minutes or more, and further preferably 10 minutes or more. 120 minutes or less is preferable, 100 minutes or less is more preferable, and 80 minutes or less is still more preferable.

  Moreover, the impregnation temperature should just be more than the temperature which an isocyanate compound is a liquid, specifically 10 degreeC or more is preferable, 20 degreeC or more is more preferable, and 30 degreeC or more is still more preferable. Moreover, from a viewpoint of the thermal deterioration of an isocyanate compound, 100 degrees C or less is preferable, 95 degrees C or less is more preferable, and 90 degrees C or less is still more preferable.

  The reaction time between the impregnated isocyanate compound and the polyurethane resin is preferably 5 minutes or more, more preferably 8 minutes or more, further preferably 10 minutes or more, from the viewpoint of reaction efficiency and thermal degradation of the polyurethane resin. Minutes or less are preferable, 100 minutes or less are more preferable, and 80 minutes or less are still more preferable. The reaction temperature is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, further preferably 50 ° C. or higher, preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and still more preferably 140 ° C. or lower.

  In the cleaning blade described above, a hardened layer with sufficient thickness is formed at the contact part with the toner carrier, so the friction coefficient is low, the hardness is high, and good sliding characteristics and durability are achieved. Is done.

<Photoreceptor manufacturing method>
The surface used in the present invention is subjected to a hardness test using a Vickers square pyramid diamond indenter in an environment of 25 ° C. and 50% humidity, and the HU (Universal Hardness Value) when pressed at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less, and is described in detail, including a manufacturing method for an electrophotographic photosensitive member having high durability elastic deformation rate Wo is not more than 65% or more 44%.

  The electrophotographic photoreceptor of the present invention preferably has mainly a laminated structure. In the electrophotographic photoreceptor of the present invention, a charge generation layer and a charge transport layer are provided in this order on a support, and a protective layer is provided on the outermost surface. Further, an undercoat layer for the purpose of preventing interference fringes or the like may be provided between the support and the charge generation layer.

  The support itself can be conductive, for example, aluminum, aluminum alloy, or stainless steel. In addition, aluminum, aluminum alloy, or indium oxide-tin oxide alloy is formed by vacuum deposition. The support having the layer formed, the plastic, the conductive fine particles (for example, carbon black, tin oxide, titanium oxide, silver particles, etc.) and the appropriate support resin impregnated into the plastic or paper, the conductive binder A plastic having a resin can be used.

  Further, a binder layer (adhesive layer) having a barrier function and an adhesive function can be provided between the support and the photosensitive layer. The binder layer is used to improve the adhesion of the photosensitive layer, improve the coatability, protect the support, cover defects on the support, improve the charge injection from the support, and protect against electrical breakdown of the photosensitive layer. It is formed. The binder layer can be formed of casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, aluminum oxide, or the like. The film thickness of the binder layer is preferably 5 μm or less, and particularly preferably 0.1 to 3 μm.

  Examples of the charge generating substance used in the present invention include (1) azo pigments such as monoazo, disazo and trisazo, (2) phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, and (3) indigo compounds such as indigo and thioindigo. Pigments, (4) perylene pigments such as perylene anhydride and perylene imide, (5) polycyclic quinone pigments such as anthraquinone and pyrenequinone, (6) squarylium dyes, (7) pyrylium salts and thiapyrylium salts ( 8) Triphenylmethane dyes, (9) inorganic substances such as selenium, selenium-tellurium and amorphous silicon, (10) quinacridone pigments, (11) azulenium salt pigments, (12) cyanine dyes, (13) xanthene dyes, 14) Quinone imine dye, (15) Su Lil dyes, and (16) cadmium sulfide and (17) zinc oxide.

  Examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, Examples thereof include, but are not limited to, silicone resins, polysulfone resins, styrene-butadiene copolymer resins, alkyd resins, epoxy resins, urea resins, and vinyl chloride-vinyl acetate copolymer resins. These can be used alone or as a mixture or as a copolymer polymer.

  The solvent used for the charge generation layer coating is selected from the solubility and dispersion stability of the resin used and the charge generation material, but examples of the organic solvent include alcohols, sulfoxides, ketones, ethers, esters, Aliphatic halogenated hydrocarbons or aromatic compounds can be used.

  The charge generation layer is well dispersed by a method such as a homogenizer, ultrasonic wave, ball mill, sand mill, attritor or roll mill, together with a binder resin and a solvent in an amount of 0.3 to 4 times the mass of the charge generation material, It is formed by coating and drying. The thickness is preferably 5 μm or less, and particularly preferably in the range of 0.01 to 1 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and known charge generating substances can be added to the charge generation layer as necessary.

  The charge transport materials used include various triarylamine compounds, various hydrazone compounds, various styryl compounds, various stilbene compounds, various pyrazoline compounds, various oxazole compounds, various thiazole compounds, and various triarylmethane compounds. Compound etc. are mentioned.

  Examples of the binder resin used for forming the charge transport layer include acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, and unsaturated resin. The resin chosen is preferred. Particularly preferred resins include polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, polycarbonate resin and diallyl phthalate resin.

  The charge transport layer is generally formed by dissolving the charge transport material and the binder resin in a solvent and applying them. The mixing ratio (mass ratio) of the charge transport material and the binder resin is about 2: 1 to 1: 2. Solvents include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride, tetrahydrofuran, Ethers such as dioxane are used. When this solution is applied, for example, a coating method such as a dip coating method, a spray coating method and a spinner coating method can be used, and drying is preferably 10 ° C to 200 ° C, more preferably 20 ° C to 150 ° C. The temperature is in the range of 5 minutes to 5 hours, and more preferably 10 minutes to 2 hours.

  The charge transport layer is electrically connected to the above-described charge generation layer, receives charge carriers injected from the charge generation layer in the presence of an electric field, and transports these charge carriers to the interface with the protective layer. It has a function. Since this charge transport layer has a limit to transport charge carriers, the film thickness cannot be increased more than necessary, but it is preferably 5 to 40 μm, and particularly preferably 7 to 30 μm.

  Furthermore, an antioxidant, an ultraviolet absorber, a plasticizer, and a known charge transport material can be added to the charge transport layer as necessary.

In the present invention, furthermore, the protective layer is applied on the charge transport layer and cured to form a film, and a hardness test is performed using a Vickers square pyramid diamond indenter in an environment where the surface is 25 ° C. and a humidity of 50%. A photoreceptor having a HU (Universal Hardness Value) of 150 N / mm ² or more and 220 N / mm ² or less when pressed with a maximum load of 6 mN and an elastic deformation rate Wo of 44% or more and 65% or less is completed. .

<Protective layer forming method 1>
As a protective layer for an electrophotographic photoreceptor satisfying the above conditions, a compound obtained by polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule as shown in the following (Chemical Formula 1) is contained. There is a protective layer.

式中、Ａは正孔輸送性基を示す。Ｐ１及びＰ２は連鎖重合性官能基を示す。Ｐ１とＰ２は同一でも異なってもよい。Ｚは置換基を有してもよい有機残基を示す。ａ、ｂ及びｄは０又は１以上の整数を示し、ａ＋ｂ×ｄは２以上の整数を示す。また、ａが２以上の場合Ｐ１は同一でも異なってもよく、ｄが２以上の場合Ｐ２は同一でも異なってもよく、またｂが２以上の場合、Ｚ及びＰ２は同一でも異なってもよい。

In the formula, A represents a hole transporting group. P1 and P2 represent a chain polymerizable functional group. P1 and P2 may be the same or different. Z represents an organic residue which may have a substituent. a, b, and d represent 0 or an integer of 1 or more, and a + b × d represents an integer of 2 or more. When a is 2 or more, P1 may be the same or different. When d is 2 or more, P2 may be the same or different. When b is 2 or more, Z and P2 may be the same or different. .

  By polymerizing a hole transporting compound having two or more chain-polymerizable functional groups in the same molecule, the compound having a hole transporting ability in the protective layer has at least two or more crosslinking points. It is incorporated into the dimensional cross-linked structure via a covalent bond. The hole transporting compound can be either polymerized alone or mixed with a compound having another chain polymerizable group, and the kind / ratio is arbitrary. As used herein, the compound having another chain polymerizable group includes any monomer or oligomer / polymer having a chain polymerizable group. When the functional group of the hole transporting compound and the functional group of the other chain polymerizable compound are the same group or a group that can be polymerized with each other, they both take a copolymerized three-dimensional crosslinked structure via a covalent bond. Is possible. When both functional groups are functional groups that do not polymerize with each other, the photosensitive layer is a mixture of at least two or more three-dimensional cured products or other chain-polymerizable compound monomers in the three-dimensional cured product as a main component. Although it is comprised as the thing containing the hardened | cured material, it is also possible to form an IPN (Inter Penetrating Network), ie, an interpenetrating network structure, by controlling the compounding ratio / film forming method well.

  In the present invention, the protective layer contains at least one selected from the group consisting of a fluorine atom-containing resin, carbon fluoride, and polyolefin resin as a lubricant, and preferred compounds include the following. However, it is not limited to these compounds.

  Preferred as the fluorine atom-containing resin is a polymer or copolymer resin of a compound selected from vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoropropylene, perfluoroalkyl vinyl ether, and Examples include resin fine particles.

  Examples of the carbon fluoride include compounds represented by (CF) n and (C2F) n.

  Preferred examples of the polyolefin resin include homopolymer resins such as polyethylene resin, polypropylene resin and polybutene resin, copolymer resins such as ethylene-propylene copolymer and ethylene-butene copolymer, and resin powder.

  These lubricants can be used alone or in combination of two or more at any ratio.

  The protective layer may contain a dispersant for the lubricant, a dispersion aid, other various additives, a surfactant, and the like.

  By containing at least one of fluorine atom-containing resin, carbon fluoride, and polyolefin resin as a lubricant in the protective layer, the surface slipperiness and water repellency of the photoreceptor can be improved, and charging during repeated use, Deterioration of transfer efficiency and slipperiness due to chemical deterioration of the surface layer due to development, transfer, etc., and further deterioration of electrical properties such as sensitivity reduction and potential reduction are prevented. Filming, fusing, and cleaning failure even during repeated use It is possible to suppress the occurrence of image defects such as image blur / flow. Particularly preferable results are obtained when the fluorine-containing resin is used.

  In the present invention, the proportion of the lubricant contained in the protective layer is preferably 1 to 70%, more preferably 5 to 50%, based on the total weight of the layer to be the surface layer. When the amount of the lubricant is more than 70%, the mechanical strength of the layer serving as the surface layer tends to be lowered, and when it is less than 1%, the water repellency and slipperiness of the layer serving as the surface layer may not be sufficient.

  In the present invention, a charge transport material can be contained in the protective layer containing the cured product of the hole transporting compound having the chain polymerizable group.

  The protective layer is generally formed by applying a solution containing the hole transporting compound and then carrying out a polymerization reaction, but a cured product obtained by reacting a solution containing the hole transporting compound in advance. After obtaining the above, it is possible to form a protective layer by dispersing or dissolving in the solvent again. As a method for applying these solutions, for example, a dip coating method, a spray coating method, a curtain coating method, a spin coating method, and the like are known, but the dip coating method is preferable from the viewpoint of efficiency / productivity.

  In the present invention, the hole transporting compound having a chain polymerizable group is preferably polymerized by radiation. The greatest advantage of polymerization by radiation is that a polymerization initiator is not required, which makes it possible to produce a very high-purity three-dimensional photosensitive layer and to ensure good electrophotographic characteristics. In addition, because it is a short and efficient polymerization reaction, it is highly productive, and because of its high radiation permeability, it inhibits curing when thick films and additives such as additives are present in the film. The influence of the is very small. However, depending on the type of the chain polymerizable group and the type of the central skeleton, the polymerization reaction may not easily proceed, and in this case, it is possible to add a polymerization initiator within a range that does not affect the reaction. The radiation used at this time is an electron beam and a gamma ray. In the case of electron beam irradiation, any type of accelerator such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used. When irradiating with an electron beam, the irradiation conditions are very important in the photoreceptor of the present invention in order to develop electric characteristics and durability.

  In the present invention, the acceleration voltage is preferably 250 kV or less, and optimally 150 kV or less. The dose is preferably in the range of 10 kGy to 1000 kGy.

  When the accelerating voltage exceeds the above, the electron beam irradiation damage tends to increase on the characteristics of the photoreceptor. Further, when the dose is less than the above range, the curing tends to be insufficient, and when the dose is large, the photoreceptor characteristics are likely to be deteriorated.

<Protective layer forming method 2>
Furthermore, the electrophotographic photoreceptor protective layer that satisfies the conditions of the present invention is selected from the group consisting of a curable phenol resin and a hydroxyphenyl group that may have a hydroxyalkyl group, a hydroxyalkoxy group, or a substituent. There is a protective layer containing a charge transport material having at least one of the groups.

  The curable phenol resin, which is a binder resin used for the protective layer, is generally a resin obtained by a reaction between phenols and formaldehyde. There are two types of phenolic resins: a resole type obtained by reacting with phenol with an excess of formaldehyde and an alkali catalyst, and a novolak obtained by reacting with phenol and an excess of phenol with formaldehyde. Divided into molds.

  The resol type is also soluble in alcohol and ketone solvents, and is three-dimensionally crosslinked and polymerized by heating to form a cured product. On the other hand, the novolak type generally does not cure even when heated as it is, but forms a cured product by adding a formaldehyde source such as paraformaldehyde or hexamethylenetetramine and heating.

  In general, the resol type is used as a varnish for paints, adhesives, cast products and laminates, and the novolak type is mainly used as a molding material or a binder.

  The phenolic resin used as the binder resin in the present invention can be used in either the above-mentioned resol type or novolak type, but it is a resol type from the viewpoint of curing without adding a curing agent and operability as a paint. Is preferably used.

  In the present invention, these phenol resins can be used singly or in combination of two or more, and a resol type and a novolac type can also be mixed and used.

  For example, the protective layer can be formed using a polyhydroxymethylated bisphenol compound having two or more hydroxymethyl groups.

  The skeleton of the above-described bisphenol compound has a structure represented by the following formula (Chemical Formula 2).

式中、Ｘは単結合若しくは２価の結合基を、Ｒ_１及びＲ_２はそれぞれ置換基としてハロゲン原子、アリール基、ビニル基、置換基を有してもよいアルキル基、置換基を有してもよい環状アルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基又は置換基を有してもよい複素環基を表す。

In the formula, X represents a single bond or a divalent linking group, and R ₁ and R ₂ each have a halogen atom, an aryl group, a vinyl group, an alkyl group which may have a substituent, or a substituent as a substituent. A cyclic alkyl group which may be substituted, an alkoxy group which may have a substituent, an aryl group which may have a substituent or a heterocyclic group which may have a substituent;

  This polyhydroxymethyl bisphenol compound is subjected to heat treatment to form an ether bond or a further methylene bond by a condensation reaction between hydroxymethyl groups, or to form an ortho position between the hydroxymethyl group and the phenolic hydroxyl group. A methylene bond is formed by a condensation reaction with a hydrogen atom in the para position, and a three-dimensional cured film having a high crosslinking density can be obtained by the occurrence of these condensation reactions between various molecules. These condensation reactions are essentially reactions that are not hindered by moisture and oxygen in the air, and proceed sufficiently even in a system to which a charge transport material is added. The crosslinking reaction by heat treatment of the polyhydroxymethyl bisphenol compound has a feature that it is not necessary to add a curing catalyst generally used for thermosetting. Therefore, when the compound of the present invention is used as a surface layer of an electrophotographic photoreceptor, problems such as an increase in residual potential and a decrease in resistance of the outermost surface layer due to the residual curing catalyst do not occur.

  In addition, the polyhydroxymethyl bisphenol compound of the present invention does not require the addition of a curing catalyst, and the hydroxymethyl group itself is sufficiently stable against moisture unlike isocyanates and silicone resins. It is also excellent in sex.

  The protective layer of the present invention is formed by applying a coating obtained by dissolving or diluting a curable phenolic resin with a solvent or the like onto a photosensitive layer, and a polymerization reaction occurs after coating to form a cured layer. As a form of polymerization, it proceeds by addition and condensation reaction with heat, and after coating the protective layer, it is heated to cause a polymerization reaction to produce a polymer hardened layer.

  The charge transport material having a hydroxyalkyl group, a hydroxyalkoxy group or a hydroxyphenyl group which may have a substituent of the present invention is preferably a triphenylamine derivative.

  Examples of the substituent that the hydroxyphenyl group may have include halogen atoms such as fluorine, chlorine, bromine and iodine, and optionally substituted methyl, ethyl, propyl and butyl groups. Alkyl groups, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group which may have a substituent, aryl groups such as phenyl group, naphthyl group, anthryl group and pyrenyl group which may have a substituent Or heterocyclic groups such as pyridyl group, thienyl group, furyl group and quinolyl group which may have a substituent.

  Among the charge transport materials used in the present invention, the charge transport material having a hydroxyalkyl group or a hydroxyalkoxy group is preferably a compound having a specific structure represented by the following (Chemical Formula 3).

式中、Ｒ_１１、Ｒ_１２およびＲ_１３はそれぞれ炭素数１〜８の枝分かれしてもよい２価の炭化水素基を表し、α、βおよびγはそれぞれ置換基としてハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基、置換基を有してもよい複素環基を１つ以上有してもよいベンゼン環を表し、ａ１、ｂ１およびｃ１は１または０であり、ｍ１およびｎ１は０または１である。

In the formula, R ₁₁ , R ₁₂ and R ₁₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and α, β and γ each have a halogen atom or a substituent as a substituent. An optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group, and an optionally substituted heterocyclic group Represents a ring, a1, b1 and c1 are 1 or 0, and m1 and n1 are 0 or 1.

  In addition, the charge transport material used in the present invention is formed by uniformly dissolving or dispersing in a coating material for producing the protective layer and applying it. The mixing ratio of the charge transporting material and the curable phenolic resin of the present invention is preferably a mass ratio of charge transporting material / curable phenolic resin = 0.1 / 10-20 / 10, particularly 0.5 / 10-10. / 10 is preferred. If the amount of the charge transport material is too small relative to the curable phenol resin, the effect of lowering the residual potential is reduced, and if it is too much, the strength of the protective layer may be reduced.

  The protective layer used in the present invention does not essentially transfer charges as a resistor, but is an electrophotographic photosensitive member in which charges are transferred by a charge transport material contained in the protective layer and a protective layer is applied. The sensitivity is maintained and the residual potential is lowered. Therefore, it is not necessary to set the volume resistivity as a resistor low, and by setting the volume resistivity to 1 × 10 12 (Ω · cm) or more, the flow of the formed electrostatic latent image is a high dimension. Can be suppressed.

  In the electrophotographic photosensitive member having the protective layer described above, by further containing fluorine atom-containing resin fine particles, the releasability on the surface of the electrophotographic photosensitive member can be improved at a higher level.

  Examples of the fluorine atom-containing resin fine particles include ethylene tetrafluoride, ethylene trifluoride chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and copolymers thereof. Of these, it is preferable to select one or more types as appropriate, and particularly preferred are tetrafluoroethylene resin and vinylidene fluoride resin. The molecular weight distribution and particle size of the resin particles can be appropriately selected and are not particularly limited.

  As the solvent for preparing the outermost surface layer coating solution, the polyhydroxymethylbisphenol compound of the present invention and the charge transporting material are sufficiently dissolved, and further, the lower layer charge transporting layer in contact with the outermost surface layer coating solution or A solvent that does not adversely affect the charge generation layer or the like is preferable.

  Therefore, as solvents, alcohols such as methanol, ethanol and 2-propanol, ketones such as acetone, cyclohexanone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, ethers such as tetrahydrofuran and dioxane, toluene and xylene, etc. Aromatic hydrocarbons, halogenated hydrocarbons such as chlorobenzene and dichloromethane, and the like may be used in combination. Among these, the most suitable solvents for the form of the present invention are alcohols such as methanol, ethanol and 2-propanol.

  Conventionally, known charge transport materials are generally insoluble or hardly soluble in alcohol solvents, and uniform dissolution in the polyhydroxymethylbisphenol compound of the present invention is difficult. When contained, it is soluble in a solvent containing alcohol as a main component, and has little influence on the lower layer such as a charge transport layer.

  As a method for applying the outermost surface layer of the present invention, general coating methods such as a 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.

  In the present invention, an additive for an antioxidant may be added to the outermost surface layer for the purpose of preventing deterioration of the surface layer due to adhesion of active substances such as ozone and NOx generated during charging.

<Method for evaluating physical properties of photoreceptor surface>
After the hardness test photoreceptor prepared as described above is left in an environment of 25 ° C. and 50% humidity for 24 hours, Hu and elastic deformation are performed using the above-described microhardness measuring device Fischerscope H100V (Fischer). The rate Wo was determined.

  The HU (universal hardness value) and elastic deformation rate Wo in the present invention are the microhardness measuring device Fischer that continuously applies a load to the indenter and directly reads the indentation depth under the load to obtain the continuous hardness. Measurement was performed using a scope H100V (Fischer). The indenter used was a Vickers square pyramid diamond indenter with a face angle of 136 °. The load conditions were measured stepwise up to a final load of 6 mN (273 points with a holding time of 0.1 s for each point).

  An outline of the output chart is shown in FIG. 3, and an example in which the electrophotographic photosensitive member of the present invention is measured is shown in FIG. The vertical axis represents the load (mN) and the horizontal axis represents the indentation depth h (μm), which is the result of increasing the load stepwise and applying the load to 6 mN, and then decreasing the load stepwise in the same manner.

  HU (universal hardness value: hereinafter referred to as HU) is defined by the following formula (1) from the indentation depth under the same load when indented at 6 mN.

弾性変形率Ｗｏは圧子が膜に対して行った仕事量（エネルギー）、すなわち圧子の膜に対する荷重の増減によるエネルギーの変化より求めたものであり、下記式（２）からその値は求まる。全仕事量Ｗｔ（ｎＷ）は図３中のＡ−Ｂ−Ｄ−Ａで囲まれる面積で表され、弾性変形の仕事量Ｗｅ（ｎＷ）はＣ−Ｂ−Ｄ−Ｃで囲まれる面積で表される。

The elastic deformation rate Wo is obtained from the work (energy) performed by the indenter on the membrane, that is, the change in energy due to the increase or decrease of the load of the indenter on the membrane, and the value can be obtained from the following equation (2). The total work Wt (nW) is represented by an area surrounded by A-B-D-A in FIG. 3, and the elastic deformation work We (nW) is represented by an area surrounded by C-B-D-C. Is done.

Elastic deformation rate Wo = We / Wt × 100 (%) (2)
As described above, the performance required for the organic electrophotographic photosensitive member includes improved durability against mechanical deterioration. In general, the hardness of the film is higher as the amount of deformation with respect to external stress is smaller, and it is considered that the electrophotographic photosensitive member having higher pencil hardness or Vickers hardness naturally improves durability against mechanical deterioration. However, the high hardness obtained by these measurements has not always been expected to improve durability.

As a result of intensive studies, we have found that mechanical deterioration of the surface layer of the photoreceptor is less likely to occur particularly in a high temperature, high humidity environment when the values of HU and elastic deformation rate Wo are within a certain range, leading to the present invention. . That is, a hardness test is performed using a Vickers square pyramid diamond indenter, the HU when pressed at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less, and the elastic deformation rate Wo is 44% or more and 65%. The use of the following electrophotographic photosensitive member has improved dramatically. Also, the further improvement of properties and is more preferably HU value is 160 N / mm ² or more 200 N / mm ² or less.

Although the HU and the elastic deformation rate Wo cannot be separated, for example, when the HU exceeds 220 N / mm ^{2 or} when the friction with the cleaning blade increases at high temperatures, the elastic deformation rate Wo If the elastic deformation rate Wo is larger than 65%, the elastic deformation amount is small even if the elastic deformation rate is high. Deep pressure is generated due to high local pressure. Therefore, it is considered that the one with a high HU is not necessarily optimal as the photosensitive member.

Further, when the HU is less than 150 N / mm ² and the elastic deformation rate Wo exceeds 65%, even if the elastic deformation rate is high, the amount of plastic deformation increases, and the paper dust sandwiched between the cleaning blade and the charging roller If the toner is rubbed, it may be scraped off or fine scratches may occur.

In this example, two types of protective layers were formed to obtain two types of photoreceptors. <Photoreceptor Production Example 1>
Using an aluminum cylinder (JIS A3003 aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm as a support, a 5% by mass methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was applied thereon by a dipping method. An undercoat layer having a thickness of 0.5 μm was formed.

  Next, 3 parts of hydroxygallium phthalocyanine crystal and 2 parts of polyvinyl butyral having the strongest peak at a diffraction angle 2θ ± 0.2 of 28.1 ° in X-ray diffraction of CuKα as a charge generating material are added to 100 parts of cyclohexanone. Disperse in a sand mill using 1 mmφ glass beads for 1 hour, add 100 parts of methyl ethyl ketone and dilute it to prepare a charge generation layer coating, and immerse this charge generation layer coating on the undercoat layer This was applied and dried at 90 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.17 μm.

  Next, 7 parts of the charge transport material compound of the following (Chemical Formula 4)

及びポリカーボネート樹脂（ユーピロンＺ４００、三菱エンジニアリングプラスチックス（株）製）１０部を、モノクロロベンゼン１０５部及びジクロロメタン３５部に溶解した。この溶液を、前記電荷発生層上に浸漬塗布し、１１０℃で１時間熱風乾燥し、膜厚が１３μｍの電荷輸送層を形成した。電荷輸送層の上にこのさらに保護層を形成させた。

And 10 parts of polycarbonate resin (Iupilon Z400, manufactured by Mitsubishi Engineering Plastics) were dissolved in 105 parts of monochlorobenzene and 35 parts of dichloromethane. This solution was dip-coated on the charge generation layer and dried with hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 13 μm. This further protective layer was formed on the charge transport layer.

  In this embodiment, reversal development is used, and the photoreceptor is formed by stacking three layers on an aluminum cylinder having a diameter of 30 mm as described above, and then using a hole transporting compound represented by the following (Chemical Formula 5) as an electron beam. It is an organic photoreceptor in which a surface layer containing a compound polymerized by irradiation is applied and cured.

この正孔輸送性化合物４５部をｎ−プロピルアルコール５５部に溶解し、さらにテトラフルオロエチレン微粒子を５重量部添加して、高圧分散機（マイクロフルイタイザー、Ｍｉｃｒｏｆｌｕｉｄｉｃｓ社製）にて分散させた表面保護層用塗料を調整した。この塗料を前記４層感光体上に塗布したのち、加速電圧１５０ＫＶ、線量４０ｋＧｙの条件で電子線を照射し、膜厚３μｍの保護層を形成し、電子写真感光体Ａを得た。

A surface obtained by dissolving 45 parts of this hole transporting compound in 55 parts of n-propyl alcohol, adding 5 parts by weight of tetrafluoroethylene fine particles, and dispersing with a high-pressure disperser (Microfluidizer, manufactured by Microfluidics). The protective layer paint was prepared. After applying this paint on the four-layer photoconductor, an electron beam was irradiated under the conditions of an acceleration voltage of 150 KV and a dose of 40 kGy to form a protective layer having a thickness of 3 μm, and an electrophotographic photoconductor A was obtained.

<Protective layer production example 2>
Next, the second type of protective layer will be described in detail below including the manufacturing method.

  All the ortho-position hydrogen atoms of the phenolic hydroxyl group of bisphenol represented by the following (Chemical Formula 6) as the curable phenol resin as the binder resin of the protective layer on the same three-layered photoreceptor as in photoreceptor production example 1. 100 parts of a tetrakishydroxymethyl-bisphenol compound substituted with a hydroxymethyl group and 70 parts of a charge transport material represented by the following (Chemical Formula 7), 42 parts of tetrafluoroethylene fine particles, and 150 parts of ethanol are mixed, A coating liquid is prepared by dissolving in a solvent dispersed with a high-pressure disperser (microfluidizer, manufactured by Microfluidics), dip-coated on the charge transport layer, and dried with hot air at 145 ° C. for 1 hour, An outermost surface layer having a thickness of 3 μm was provided. Here, the film thickness of the outermost surface layer was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd.).

以上のように作製した保護層を有する感光体を感光体Ｂとする。

The photoreceptor having the protective layer produced as described above is referred to as a photoreceptor B.

  Table 1 shows the values of Hu and Wo on the surfaces of the obtained photoreceptor A and photoreceptor B.

＜クリーニングブレード＞
さらに本発明に使用する硬度・摩擦係数を変化させたポリウレタン樹脂のクリーニングブレードＡ〜Ｉの硬度・摩擦係数を表２に示す。

<Cleaning blade>
Further, Table 2 shows the hardness and friction coefficient of the polyurethane resin cleaning blades A to I used in the present invention in which the hardness and friction coefficient are changed.

  The blade E is obtained by impregnating and curing (ID treatment) isocyanate on the edge surface layer of the blade D. Specifically, 1,4-butanediol and trimethylolpropane were added to a prepolymer having an NCO% of 7.0% and produced from an ethylene butylene adipate polyester polyol having a weight average molecular weight of 2000 and 4,4'-diphenylmethane diisocyanate. Was mixed with a cross-linking agent containing a triethylenediamine catalyst mixed in a mass ratio of 65:35 so that the molar ratio of hydroxyl group / isocyanate group was 0.9, to produce a thermosetting polyester polyurethane resin blade. . The obtained polyurethane resin blade was masked with a mask member 41 made of a chemical-resistant tape so as to form a cured layer only at the edge portion in contact with the photoreceptor, and immersed in an isocyanate (MDI) bath at 80 ° C. for 10 minutes. The blade made of polyurethane resin was pulled up from the MDI bath, the excess MDI was wiped off, and the masking was removed. Thereafter, the impregnated isocyanate compound and the polyurethane resin were reacted in an oven at 130 ° C. for 60 minutes to prepare a cleaning blade E.

以上のようにして得られた感光体Ａ・Ｂ、クリーニングブレードＡ〜Ｉを使用して実機に実装して評価し、実施例および比較例とした。

The photoreceptors A and B and the cleaning blades A to I obtained as described above were mounted on an actual machine and evaluated, and examples and comparative examples were obtained.

<Evaluation method>
Evaluation was performed using a Canon digital copying machine GP405 remodeling machine. The GP405 remodeling machine is provided with a fur roller brush that rotates following the photosensitive member on the upstream side of the cleaning blade.

  The fatty acid metal salt is supplied by adding 0.1% of calcium stearate to the toner in the developing device so that the fatty acid metal salt is supplied from the developing device to the photoreceptor, or in contact with the fur brush roller. A rod-like solid obtained by solidifying calcium stearate in a form was attached, and the powder was scraped off as powder from the calcium stearate rod by rotation of a fur brush roller and adhered to the surface of the photoreceptor. The working environment was a low humidity environment (N / L) with a temperature of 23 ° C. and a humidity of 5% and a high humidity environment (H / H) with a temperature of 30 ° C. and a humidity of 80%. The image output conditions were 8000 sheets of 2% horizontal line originals with continuous paper feeding.

  There are four evaluation items: blade squeal, blade chipping, toner slippage, and image flow.

  The cleaning blade squeal was performed by evaluating the actual machine in the H / H environment according to the following criteria.

◎ There is almost no squeak. ○ There is squeal, but it is small and is not worrisome. △ Slight squeal only when the photoconductor rotation is stopped. × The sound of the cleaning blade is loud and can be heard even if you leave the actual machine. The evaluation was performed based on the following criteria on an actual machine in the / H environment.

◎ No chipping ○ Cleaning is done without any problem, but blade edge is curled or deformed △ The edge is chipped and the toner slips slightly, but the effect is not noticeable in the output image × The blade edge is chipped In the N / L environment, the image was evaluated by the following criteria using an actual machine.

◎ There is almost no slip-through. ○ Slightly passes, but there is no effect on the image. △ There is a little slip-through, but the charging means is slightly dirty and is not noticeable in the output image. × Slip-through is bad and the image is stained. After printing 8000 sheets in the environment, the output image was evaluated in the morning in the actual machine based on the following criteria.

◎ No image flow ○ Slight image flow is seen in halftone △ Characters are slightly blurred when viewed closely × Characters are completely blurred and cannot be read Implementation evaluated with the above configuration and evaluation items The results of Examples and Comparative Examples are shown in Table 3.

実施例１〜２０で示されるように、脂肪酸金属塩を感光体上に塗布する手段を設け、ゴム硬度７８度以上９９度とすることでブレード鳴き・ブレード欠け・トナーすり抜け・画像流れの観点で、低湿および高湿環境においても問題の無い出力画像が得られた。

As shown in Examples 1 to 20, a means for applying a fatty acid metal salt on a photoreceptor is provided, and the rubber hardness is set to 78 degrees or more and 99 degrees from the viewpoint of blade squealing, blade chipping, toner slipping, and image flow. An output image having no problem was obtained even in a low and high humidity environment.

  As shown in Examples 1 to 20, by setting the dynamic friction coefficient of the cleaning blade to the PET sheet to be 0.2 or more and 1.2 or less, particularly, it is possible to achieve both reduction of the cleaning blade chip and prevention of toner slipping, and no problem image. Formation was possible.

  As shown in Examples 3, 8, 13, and 18, the ID treatment is performed, and the concentration of the isocyanate group on the surface portion of the cleaning blade in contact with the photosensitive member is made larger than the concentration of the isocyanate group inside the blade. As a result, the edge of the cleaning blade was eliminated and high durability without impairing the cleaning performance was obtained.

  As shown in Examples 1 to 8 and 11 to 18, when the elastic deformation rate of the photoreceptor surface is Wo and the rubber hardness of the cleaning blade is H, the configuration satisfying the relational expression of H / Wo <2. By doing so, blade squeal can be further suppressed.

  As shown in Examples 6 to 10 and 16 to 20, the protective layer of the photoreceptor is made of a curable phenol resin and a hydroxyphenyl group, a hydroxyalkoxy group, or a hydroxyphenyl group which may have a substituent. By containing a charge transport material having at least one selected group, it is possible to further suppress image flow at high humidity while maintaining high elasticity and high durability.

  As shown in Examples 1 to 10, the fatty acid metal salt is externally added to the toner so that the fatty acid supply means also serves as the developing means, so that it is not necessary to newly provide the fatty acid supply means, and low cost and space saving. Can be achieved.

  As shown in Examples 11 to 20, when the fatty acid supply unit also serves as the cleaning auxiliary unit, the fatty acid metal salt can be sufficiently supplied to the surface of the photoreceptor without loss to the cleaning blade edge portion, and the cleaning performance is improved. be able to.

Schematic sectional view showing an image forming apparatus of the present invention Schematic sectional view of a cleaning blade fixing device for friction coefficient measurement of the present invention Schematic of output chart for measuring elastic modulus of electrophotographic photosensitive member of the present invention The figure which shows the example which measured the elasticity modulus of the electrophotographic photoreceptor of this invention

Explanation of symbols

101 photoconductor 102 charging roller (primary charger)
103 Exposure Unit 104 Developer (Development Unit)
105 Transfer charger (transfer means)
106 Fixing Device 107 Cleaning Device 111 Transfer Material 201 PET Sheet 202 Cleaning Blade 203 Cleaning Blade Fixing Member

Claims (7)

Hardness test is performed using a Vickers square pyramid diamond indenter in an environment of 25 ° C and 50% humidity, and the HU (Universal Hardness Value) when pressed at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less. And an electrophotographic photosensitive member having a surface with an elastic deformation rate Wo of 44% to 65%, a means for forming a latent image on the photosensitive member, and a developing means for developing the latent image with toner. In an image forming apparatus having transfer means for transferring developed toner to a transfer material and cleaning means for removing toner remaining on the photoreceptor after transfer with a cleaning blade, a fatty acid metal salt is applied to the surface of the photoreceptor. An image forming apparatus comprising: a fatty acid metal salt supplying means for supplying; and a rubber hardness of the cleaning blade of 78 degrees or more and 99 degrees or less. .   The image forming apparatus according to claim 1, wherein the cleaning blade has a coefficient of dynamic friction with respect to the PET sheet of 0.2 to 1.2.   3. The image forming apparatus according to claim 1, wherein the concentration of the isocyanate group in the surface portion of the cleaning blade in contact with the photosensitive member is greater than the concentration of the isocyanate group in the blade. When the rubber hardness of the cleaning blade is H, the following formula H / Wo <2
The image forming apparatus according to claim 1, wherein:   The photoreceptor has a protective layer, and the protective layer is at least one selected from the group consisting of a curable phenol resin and a hydroxyphenyl group, a hydroxyalkoxy group, or a hydroxyphenyl group which may have a substituent. The image forming apparatus according to claim 1, further comprising a charge transporting material having one of them.   6. The image forming apparatus according to claim 1, wherein the fatty acid metal salt coating unit also serves as a developing unit. 6. The image forming apparatus according to claim 1, wherein the fatty acid metal salt coating unit also serves as a cleaning auxiliary unit provided upstream of the cleaning unit.

Images