JP5577589B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to prevention of damage on the surface of a latent image carrier such as a photoconductor used during image formation.

In an image forming apparatus using an electrophotographic process, image formation is performed by subjecting a photoreceptor used as a latent image carrier to a charging step, an exposure step, a development step, and a transfer step.
The image forming apparatus described above includes a printer used as an output device of a personal computer, a facsimile device used as an output device of an information reception signal, a digital copying machine capable of forming an image based on image information using a digital signal, There are devices that combine these functions.

On the other hand, some image forming apparatuses can form not only monochrome images but also multicolor images including full-color images.
The configuration of the full-color image forming apparatus is a configuration called a revolver type in which a developing unit for each color can be faced by rotating it toward a developing position on a photosensitive member as a latent image carrier (for example, a patent) Document 1) or a configuration called a tandem type in which image forming portions of respective colors are provided in parallel along the extending direction of an intermediate transfer member such as a belt (for example, Patent Document 2) is known.

  The revolver-type configuration requires only one photoconductor, and thus can reduce the size of devices that have been increasingly demanded in recent years. However, since a plurality of image forming processes are required, a lot of runtime is required, which is a disadvantageous configuration in speeding up the image forming process.

On the other hand, the tandem type configuration can sequentially transfer images of each color as the transfer body moves through each image forming unit, and a full color image or the like can be obtained by collectively transferring the superimposed and transferred images. . As a result, although the above-described multiple image forming processes are unnecessary, the speed can be increased. On the other hand, since the space for expanding the transfer body is necessary to arrange the image forming portions of the respective colors, the apparatus becomes large. There are disadvantages.
However, from the viewpoint of speeding up, the current situation is that tandem-type image forming apparatuses have attracted attention.

  FIG. 6 is a schematic diagram showing the tandem type image forming apparatus 1. In FIG. 6, the intermediate transfer belt 101 provided for executing the primary transfer process is shown on the extended surface for each color along the extending direction. Are arranged side by side (indicated by symbols K, C, M, and Y indicating complementary colors in FIG. 6).

  Each image forming unit also receives a photosensitive drum 102 image which is a rotatable latent image carrier. Around the photosensitive drum 101, a charging device 102 for executing image forming processing, writing A device 103, a developing device 104, and a cleaning device 105 are arranged. At a position facing the photoconductor drum 101, a transfer device 106 is provided that includes an intermediate transfer belt 106A that can move while contacting the photoconductor drum 101 and a primary transfer roller 106B that is a transfer bias member. At a position where the image from the image forming unit is superimposed and transferred, the secondary transfer roller 107 that collectively transfers the image to the recording paper S fed from the paper feeding device, and the recording paper S after the secondary transfer. A fixing device 108 is disposed at a position where the movement of.

  In the case of forming a full-color image, the photosensitive drum 101 is uniformly charged by the charging device 102 in the rotating process, and the electrostatic latent image is generated by the laser light emitted according to the image information in the writing device 103. It is formed.

  The electrostatic latent image on the photosensitive drum 101 is subjected to a visible image processing by the developer D supplied from the developing device 104 to be a toner image, and the toner image is sequentially transferred to the intermediate transfer belt 106A. After the primary transfer process, the photosensitive drum 101 is cleaned by the cleaning device 105 and is prepared for new image formation.

  The superimposed image on the intermediate transfer belt 106A is batch-transferred onto the recording paper by the secondary transfer roller 107, and the recording paper S passes through the fixing device 108 and is fixed on the recording paper.

In addition to the two-component developer containing toner and carrier, the developer used in the above-described image forming apparatus includes, for example, a one-component developer using only non-magnetic toner as a low-cost developer.
The toner is fixed by being melted by the heat at the time of fixing and penetrating into the recording sheet or the like. At this time, hot offset may occur. Therefore, in order to prevent such hot offset, the one-component developer contains an external additive containing a silica component that assists the charging property and a component that assists glossiness such as wax, and is fixed in an oil-free manner. Is realized.

  However, when an internally added component such as wax is used, mechanical stress is applied due to friction charging work by stirring and mixing in the developing device or scraping by a layer thickness control member performed after being supported on the developing member. The internal components may ooze out on the toner surface due to the receiving. Such seepage of the internal additive component deteriorates the fluidity of the toner, and as a result, the condensing force between the toners increases, and the toner tends to adhere to the photoreceptor.

  In order to solve such problems, the fluidity of the toner is ensured by the external additive component. However, the external additive component has an extremely small particle size compared to the toner base, and the surface area of the toner base is limited. Therefore, when the coverage of the external additive component is increased, the external component easily peels off from the toner base when subjected to the mechanical stress described above.

  Conventionally, a cleaning device has been provided to remove untransferred toner remaining on the photoconductor after transfer and discharge products due to charging. However, an external component released from the toner passes through the cleaning member and accumulates. There is a risk of causing a ming phenomenon.

  The cleaning device is provided with a blade member that comes into pressure contact with the photosensitive member. However, a fine flaw may occur on the surface of the photosensitive member due to the pressure contact of the blade. Such fine scratches become a portion where the above-mentioned external additive components and untransferred toner are deposited, and if toner adheres from this scratch portion, condensation may occur and the filming phenomenon may be further promoted, resulting in poor cleaning. is there. The defective cleaning includes a problem that the background of the photoconductor is contaminated and an abnormal image with a remarkable background is obtained.

By the way, on the surface of the photosensitive member that is in pressure contact with a cleaning blade that is provided for the purpose of removing untransferred toner and discharge products, the cleaning blade that is in contact with the surface may generate abnormal noise such as chatter noise due to vibration. .
In particular, if the contact pressure of the cleaning blade against the surface of the photoreceptor, which is one of the factors that improve the cleaning performance by the cleaning blade, is increased, vibration due to friction between the blade tip and the surface of the photoreceptor increases. Vibration noise is likely to occur. Specifically, when a rubber blade such as polyurethane is used as the blade material, the frictional vibration at the blade tip increases by increasing the contact pressure of the blade. Furthermore, in a high temperature environment, a phenomenon occurs in which the rebound resilience of the blade increases, and the resonance at the blade contact position on the tourist body surface side is amplified, resulting in an uncomfortable combination of blade vibration and photoconductor resonance. Vibration sound is generated.

As a configuration for suppressing such abnormal noise caused by vibration due to frictional contact, there is a method of reducing frictional resistance by supplying a lubricant to the surface of the photoreceptor.
As a configuration for supplying the lubricant to the surface of the photosensitive member, a brush roller that can rotate in contact with the photosensitive member and in contact with the lubricant is used, and the lubricant is scraped off when the brush roller is pressed and contacted. Is applied to the surface of the photoconductor (for example, Patent Document 3), or a lubricant is contained in the toner, and lubrication is performed in accordance with the contact of the toner with the surface of the photoconductor during the visible image processing of an image. A configuration in which the agent is supplied to the surface of the photoreceptor (for example, Patent Document 4). There is.

  On the other hand, as a configuration for suppressing the occurrence of scratches that cause filming on the surface of the photoreceptor, a curable protective layer containing a high-hardness filler is provided on the surface of the photoreceptor, or a crosslinked resin film is formed. A configuration has been proposed (for example, Patent Documents 5 and 6).

JP 2007-259443 A JP 2007-077854 A JP 2000-231298 A Japanese Patent Laid-Open No. 11-184340 JP 2002-258499 A JP 2000-66424 A

  As disclosed in Patent Document 3, in the structure for supplying the lubricant by the brush roller, which is a configuration for reducing friction on the surface of the photoreceptor, a lubricant supply device is used in addition to the device used for the image forming process. I need. For this reason, in an image forming apparatus in which cost saving and space saving are desired, there is a risk of increasing the cost and increasing the size of the apparatus due to the configuration for preventing abnormal noise.

  In addition, as disclosed in Patent Document 4, in a configuration in which a lubricant is contained and supplied in the toner, the lubricant often has a smaller particle diameter than the toner, which makes it possible to provide a cleaning blade. There are many opportunities to slip through. For this reason, it is necessary to prevent the slipped lubricant from scattering and adhering to the charging device or the like. In order to prevent such scattering from adhering to the charging device, it is necessary to configure the charging device so that it does not come into contact with the surface of the tourist body. .

  On the other hand, in Patent Documents 5 and 6 that disclose a structure for preventing scratches on the surface of the photoconductor, the hardness of the surface of the photoconductor is increased in order to improve the scratch resistance. For this reason, the hardness on the surface of the photoconductor increases, the elastic modulus at the surface decreases, the repulsive force of the blade increases, and as a result, the repulsive vibration of the blade increases and the bladeless phenomenon and the wrinkle phenomenon May newly occur.

  An object of the present invention is to prevent the occurrence of scratches on the surface of the conventional image forming apparatus, particularly a photoreceptor used as a latent image carrier, and to ensure that abnormal noise is generated between contact members such as blades. An object of the present invention is to provide an image forming apparatus having a configuration capable of preventing deterioration of the working environment at the apparatus installation location due to durability and generation of abnormal noise.

In order to achieve this object, the present invention has the following configuration.
(1) A developing device that develops an electrostatic latent image formed on a uniformly charged latent image carrier with a visible magnetic image using a nonmagnetic one-component toner containing a wax, and developed. And a cleaning device for removing untransferred toner on the latent image carrier after passing through the transfer device. The transfer device moves while contacting the latent image carrier. And a transfer member capable of applying a bias to transfer a toner image to the belt body, and the cleaning device uses a blade made of an elastic body in contact with the surface of the latent image carrier. In the image forming apparatus
The transfer member is offset at a position other than the position facing the latent image carrier in the moving direction of the belt body, and is disposed at a position where the belt body can be partially mounted on the latent image carrier.
As the latent image carrier, an electrophotographic photosensitive member is used, and the electrophotographic photosensitive member includes at least a binder resin in the photosensitive layer.

and

A polycarbonate copolymer resin A containing a repeating unit represented by:

In which the weight ratio of the polycarbonate copolymer resin A and the polycarbonate resin B is set in the range of 60:40 to 90:10, and the universal hardness of the surface is image forming apparatus characterized by 150~175N / ^m m ² and elastic work ratio is set to 30-40%.
(2) A transfer roller is used as the transfer member, and a distance at which an axial center of the transfer member is offset in a moving direction of the belt body is set to 5 to 10 mm. Image forming apparatus.
(3) The image forming apparatus according to (1), wherein in the electrophotographic photoreceptor, the charge generating agent in the photosensitive layer is Y-type oxytitanium phthalocyanine.
(4) The electrophotographic photoreceptor has a charge transfer agent in the photosensitive layer.

(In the formula, R _{1 to} R ₃ are each independently hydrogen, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a substituted or unsubstituted group having 6 to 12 carbon atoms. Represents an aryl group.)
The image forming apparatus according to (1) or (3) , wherein the image forming apparatus is a distyryl charge transfer agent represented by the formula:
(5) The electrophotographic photoreceptor is characterized in that it comprises the photosensitive layer phenol antioxidant as an additive contained in the amine antioxidant and benzotriazole-based ultraviolet absorber (1), ( The image forming apparatus according to any one of 3) and (4) .
( 6 ) In the electrophotographic photoreceptor, tetrahydrofuran is used as a solvent for dissolving the components of the photosensitive layer and forming the photosensitive layer. (1), (3) to (5 ) the image forming apparatus according to any one of).
( 7 ) The image forming apparatus according to (1), wherein the belt body has a universal hardness of 10 to 120 N / mm ² .
( 8 ) The image forming apparatus according to (1), wherein a transfer roller used for the transfer member is made of metal.
( 9 ) The transfer roller is provided so as to be able to come into contact with and separate from the belt body, and when the belt is in contact with the belt body, the belt body is mounted on a part of the peripheral surface of the latent image carrier. (1), (2), (8) The image forming apparatus as described in any one of (8) characterized by the above-mentioned.
( 10 ) The transfer roll is provided so as to be able to come into contact with and separate from the belt body in each of the image forming portions for a plurality of color images, and when forming an image in a single color, the belt excluding the transfer roller at the transfer position of the corresponding color characterized in that it is configured to be separated from the body (1), (2), the image forming apparatus according to any one of (8) and (9).
( 11 ) The distance between the surface of the transfer roll and the surface of the image carrier on a line connecting the axis of the latent image carrier and the transfer roller is set to be larger than the thickness of the transfer belt (1), (2) The image forming apparatus according to any one of ( 8) to (10) .
( 12 ) The image forming apparatus according to (1) or ( 10 ), wherein the movement driving member used in the belt body is movable in a direction opposite to that during image formation during non-image formation.

  According to the present invention, it is possible to prevent the generation of noise due to the frictional vibration of the cleaning blade by setting the softness on the surface of the photoconductor by setting the universal hardness and elastic power on the surface of the photoconductor. In this configuration, the arrangement of the transfer member used in the transfer device is offset at a position other than the position facing the photoconductor, so that the transfer member does not directly collide with the photoconductor, but both these members By setting the belt member of the transfer device positioned between the belt member to a part of the surface of the photosensitive member, it is possible to suppress the occurrence of scratches on the surface of the photosensitive member by a buffer function when the belt member collides.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of an image forming apparatus according to the present invention. In FIG. 1, as in the tandem image forming apparatus shown in FIG. A configuration of a main part of an image forming unit for color (image forming unit indicated by reference numeral K in FIG. 6 for black in FIG. 1) is disclosed.

  In FIG. 1, an electrophotographic photosensitive drum (hereinafter, referred to as a photosensitive drum for convenience) 51 that is a latent image carrier is rotatably provided in the image forming unit, and around the photosensitive drum 51 is indicated by an arrow. A charging device 80, a writing device 81, a developing device 82, and a cleaning device 83 that perform image forming processing are arranged along the rotation direction shown.

  At a position after passing through the developing device 82 in the rotation direction of the photosensitive drum 51, a transfer device 670 for transferring a toner image subjected to a visible image processing by the developer supplied by the developing device 82 is provided. .

The charging device 80 includes a charging roller 80A, and is a bias member for uniformly charging the photosensitive layer provided on the photosensitive drum 51. The writing device 3 receives a laser light source (not shown) according to image information. This is an apparatus for forming an electrostatic latent image on a photosensitive layer by emitted laser light.
As shown in FIG. 1, the charging device 80 shown in FIG. 1 applies contact roller charging that uniformly charges the surface of the photosensitive member by applying a high voltage to the core of the charging roller that contacts the surface of the photosensitive drum 51. Although a method is used, it is also possible to use a non-contact charging method such as a corotron method or a scorotron method that applies a high voltage to the charge wire, and further, a charging brush, a charging sheet, a needle electrode, etc. It is also possible to use a method using. The non-contact charging method has an advantage that there is no transfer of foreign matter from the surface of the photosensitive drum, but the amount of discharge products such as ozone and NOx generated at the time of discharge is larger than that of the contact charging method. There are disadvantages. For this reason, a charging method in which a slight gap is provided between the surface of the photosensitive drum 1 and the charging roller is approached may be used.

  In the developing device 82, a non-magnetic one-component toner is used as a developer, and a toner loaded with a charge amount by frictional charging by stirring in the developing tank has a layer thickness defined by a layer thickness maintaining regulating member 82A such as a doctor blade. Then, it is carried on the surface of the developing sleeve 82B. The toner carried on the developing sleeve 82B is electrostatically attracted to the electrostatic latent image formed on the photosensitive drum 51. At this time, a developing bias for causing the toner to fly toward the photosensitive drum 1 is applied to the developing sleeve 82B.

  The toner image carried on the photosensitive drum 51 is transferred to the intermediate transfer belt 58 using a belt body provided in the transfer device 670 by a primary transfer process.

  The transfer device 670 is configured to transfer a toner image to the intermediate transfer belt 58 by a transfer bias from a transfer roller 57 that is a transfer member opposed to the intermediate transfer belt 58.

  The positional relationship between the intermediate transfer belt 58 and the transfer roller 57 with respect to the photosensitive drum 51 will be described in detail later as a feature of the present invention.

  The cleaning device 83 includes a cleaning blade 83A that comes into contact with the photosensitive drum 51 and a neutralization device 83B. The untransferred toner and discharge products remaining on the photosensitive drum 51 are scraped and scraped off by the cleaning blade 83A. The remaining charge on the subsequent photosensitive drum 51 is neutralized to prepare the photosensitive drum 51 for new image formation.

  Although not shown, the intermediate transfer belt 58 is a sheet feeding device (not shown) via a secondary transfer device to which a superimposed image obtained by sequentially transferring color images formed in each image forming unit is applied with a transfer bias. The recording paper S fed from (see FIG. 3) is subjected to a batch transfer process by a secondary transfer roller 60 (see FIG. 3).

In the image forming unit of the image forming apparatus shown in FIG. 1, a negative-positive image is formed, and the steps for this are as follows.
The surface of the photosensitive drum 51 is uniformly negatively charged by the charging device 80, and an electrostatic latent image is formed on the photosensitive drum 51 by laser light corresponding to image information. As described above, the electrostatic latent image formed on the photosensitive drum 51 is subjected to a visible image processing with the toner supplied from the developing device 82 to be a toner image, and is subjected to a primary transfer process on the intermediate transfer belt 58. Transcribed.

The formed superimposed images sequentially transferred to the intermediate transfer belt 58 are collectively transferred to the recording sheet via the secondary transfer roller 60 (see FIG. 3).
The photosensitive drum 51 after the primary transfer is prepared for a new image formation via the cleaning device 83 as described above. The toner image on the recording paper collectively transferred by the secondary transfer roller 60 is fixed by melting and permeating the recording paper by receiving heat and pressure in the process of passing through the fixing device 100 shown in FIG. Is discharged.

The structure of the photosensitive drum 51 is shown in FIG.
In the electrophotographic photoreceptor used for the photoreceptor drum 51 in FIG. 2, a charge generation layer 51A2 containing at least a charge generation agent is formed on a conductive support 51A1, and at least a charge transfer agent is contained thereon. A function-separated electrophotographic photosensitive member in which the charge transfer layer 51A3 to be formed is formed is applied. In this case, the photosensitive layer 51A is formed by the charge generation layer and the charge transfer layer.

  Various methods can be used as the method for forming the charge generation layer 51A2. For example, an oxytitanium phthalocyanine pigment is used as a charge generation agent, and a coating solution dispersed or dissolved in a suitable solvent together with a binder resin is used as a predetermined method. It can apply | coat on the support body used as a base | substrate, and can be dried and formed as needed.

  The charge transfer layer 51A3 has at least the charge transfer agent of the present invention, which will be described later. For example, the charge transfer layer 51A3 is formed by using a binder resin and a charge transfer agent on the charge generation layer 51A2 serving as the base. It can be formed by binding.

  Various methods can be used as the method for forming the charge transfer layer 51A3, but in the usual case, a coating solution in which a charge transfer agent is dispersed or dissolved in a suitable solvent together with a binder resin is used as a base charge generation layer. The method of applying on 51A2 and drying can be used.

  Further, the present invention can also be applied to an inversely stacked electrophotographic photosensitive member in which the charge generation layer 51A2 and the charge transfer layer 51A3 are stacked upside down. Furthermore, the present invention can also be applied to a single layer type electrophotographic photosensitive member containing a charge generating agent and a charge transfer agent in the same layer. If necessary, an intermediate layer may be provided between the conductive support 51A1 and the charge generation layer 51A2, or a protective layer may be provided on the photosensitive layer 51A.

  Examples of the conductive support 51A1 that can be used in the present invention include simple metals such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, indium, and alloys thereof. A processed body is mentioned. The shape may be any shape as long as it is flexible, such as a sheet shape, a film shape, and a belt shape, and may be endless or endless. The diameter of the conductive support is particularly effective when it is 60 mm or less, preferably 30 mm or less.

  The thickness of the conductive support 51A1 is 0.6 to 1.5 mm, and more preferably 0.7 to 1.2 mm, from the viewpoint of reducing vibration. When the thickness is 0.6 mm or less, the strength of the support is insufficient, and it is difficult to maintain straightness and flare accuracy, and there are problems such as color shift in a full-color image. On the other hand, if the thickness is 1.2 mm or more, the material cost increases and the cost increases.

  Among these, aluminum alloys such as JIS 3000 series, JIS 5000 series, and JIS 6000 series are used, and EI (Extension Ironing) method, ED (Extension Drawing) method, DI (Drawing Ironing) method, II (Impact Ironing) method, etc. The conductive support 51A1 formed by a simple method is preferable. Further, the surface of the conductive support 51A1 is subjected to surface treatment such as diamond cutting or polishing, surface treatment such as polishing, anodizing treatment, or the like. Any one such as a non-cutting tube that does not perform the above process may be used.

  Moreover, when using resin as a base | substrate, conductive agents, such as metal powder and conductive carbon, can be contained in resin, and conductive resin can also be used as base | substrate formation resin.

  Further, when glass is used for the substrate, the surface thereof may be coated with tin oxide, indium oxide, or aluminum iodide so as to have conductivity.

  Furthermore, an intermediate layer may be formed on the conductive support 51A1. This intermediate layer has an adhesion improving function, a barrier function for preventing an inflow current from the aluminum tube, a defect covering function on the surface of the aluminum tube, and the like. Various resins such as polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, nylon resin, alkyd resin, and melamine resin are used for this intermediate layer. be able to. These resin layers may be composed of a single resin or a mixture of two or more resins. Moreover, a metal compound, carbon, silica, resin powder, etc. can be dispersed in the layer. Furthermore, various pigments, electron accepting substances, electron donating substances, and the like can be contained for improving the characteristics.

  These intermediate layers can be formed using an appropriate solvent, dispersion, and coating method in the same manner as the photosensitive layer. The film thickness of the intermediate layer is 0.1 μm to 50 μm, preferably 0.5 μm to 20 μm.

  As a charge generating agent that can be used in the present invention, oxytitanium phthalocyanine is desirable because of its high sensitivity characteristics. Among them, Y-type oxytitanium phthalocyanine in the X-ray diffraction peak diagram shown in FIG. 3 is the charge transfer of the present invention. Good compatibility in combination with agents.

  These charge generating agents may be used alone or in combination of two or more in order to obtain an appropriate photosensitivity wavelength and sensitizing action. The film thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.1 to 2 μm.

  Next, as a binder resin used in the photosensitive layer of the present invention, a polycarbonate copolymer resin A containing a repeating unit represented by chemical structural formula 5 and chemical structural formula 6 and a polycarbonate represented by chemical structural formula 7 Both resin B are included. The contents of the chemical structural formulas 5, 6, and 7 correspond to the contents of the chemical structural formulas 1, 2, and 3, respectively.

and

  The polycarbonate copolymer resin A: the polycarbonate resin B (weight ratio) is suitably in the range of 60:40 to 90:10, and the ratio of the polycarbonate copolymer resin A is smaller than the above range. Abnormal noise is generated, and when the noise is increased, image density decreases due to deterioration of the surface of the photoreceptor due to ozone and nitrogen oxide generated in the electrophotographic apparatus.

  On the other hand, in the electrophotographic photoreceptor used in the present invention, in the above-described polycarbonate copolymer resin A, a polycarbonate containing siloxane can be further copolymerized in the photosensitive layer.

  As an example, the charge transfer agent used in the present invention contains a compound represented by the chemical structural formula 8 (the content of the chemical structural formula 8 corresponds to the content of the chemical structural formula 4).

(In the chemical structural formula 8, R _{1 to} R ₃ are each independently hydrogen, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an alkoxy group, a substituted group having 6 to 12 carbon atoms, or It represents an unsubstituted aryl group.) The details of the charge transfer agent will be described later.

  In the above-described polycarbonate copolymer resin A contained in the photosensitive layer, a polycarbonate containing siloxysan can be copolymerized, and specifically, siloxanes represented by chemical structural formula 9 and chemical structural formula 14 are formed. Polycarbonate resin containing is raised.

(In the chemical structural formula 9, R _{10 and} R ₁₁ are each independently a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. Any one of a -l group, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, a is an integer of 1 to 200, and X ₁ is- O-, or chemical structural formula 10 or chemical structural formula 11 (R ₁₃ in chemical structural formula 10 is a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or 6 to 12 carbon atoms. A substituted or unsubstituted aryl group, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and b and b ′ are each independently An integer of 0 to 6, d is 0 to Of an integer.) Represents a group represented by, _{X 2} is -O-, or in the chemical structural formula 12 or 13 (structural formula _{12, R 14} is a hydrogen atom, a halogen atom, a trifluoromethyl group, An alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms Represents one of the groups.), F and f ′ each independently represents an integer of 0 to 6, and l represents an integer of 0 to 4.

(In chemical structural formula 14, R _{21 to} R ₃₂ each independently represent either an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and m, n, and p are: Each independently represents an integer of 2 to 6, and q represents an integer of 0 to 200.)
In the case where the photosensitive layer comprises a charge generation layer and a charge transfer layer, the resin can be applied to either layer.

  The amount of the binder resin when used for the charge generation layer 51A1 is 10 to 500 parts by weight, preferably 25 to 300 parts by weight, per 100 parts by weight of the charge generation agent.

Next, the detail regarding the charge transfer agent mentioned above is demonstrated.
As the charge transfer agent, a compound represented by the chemical structural formula 8 is contained. By containing this compound, compatibility with the binder resin contained in the electrophotographic photoreceptor of the present invention is improved, and the environment resistance is improved. It is now possible to provide electrophotographic photoreceptors that are highly resistant.

  In the compound represented by the chemical structural formula 8, the compounds represented by the chemical structural formulas 15 to 18 listed below are particularly preferable because of good compatibility with the binder resin described above.

In the present invention, the ratio of the binder resin to the charge transfer agent is preferably in the range of 1.25 to 2.5 (weight ratio). More preferably, it is 1.5 to 2.0 (weight ratio). If it is more than 2.5 (weight ratio), the electrical characteristics deteriorate, for example, the residual potential increases. On the other hand, when it is less than 1.25 (weight ratio), mechanical properties such as wear resistance are deteriorated.
Furthermore, the compound represented by the chemical structural formula 9 and other charge transfer agents can be mixed and used. In this case, the content ratio of the compound of the chemical structural formula 9 and other compounds is the compound represented by the chemical structural formula 9: other compounds = 50: 50 to 95: 5, preferably 70:30 to 95: 5. The range is good.

  Other charge transfer agents include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, poly Conductive polymer compounds such as isothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrocenylene, polyperinaphthylene, and polyphthalocyanine can be used. Further, as a low molecular compound, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, indole, carbazole, Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene and the like can be used. Further, a polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethacrylic acid or the like is doped with a metal ion such as Li ion can also be used. Furthermore, an organic charge transfer complex formed of an electron donating compound typified by tetrathiafulvalene-tetracyanoquinodimethane and an electron accepting compound, etc. can be used. Desired photoreceptor characteristics can be obtained by mixing and adding the above compounds.

  As the solvent for producing the electrophotographic photosensitive member used in the present invention, tetrahydrofuran is suitable from the viewpoint of the solubility of the binder resin and the charge transfer agent, the stability of the produced solution, and the burden on the environment.

  In the coating solution for producing the electrophotographic photoreceptor used in the present invention, an antioxidant, an ultraviolet absorber, a radical scavenger, a softener, a curing agent, a crosslinking agent, etc. are added, and the characteristics of the photoreceptor, Durability and mechanical properties can be improved. In particular, the combined use of an antioxidant and an ultraviolet absorber contributes to improving the durability of the photoreceptor and is useful. Among them, amine-based antioxidants are preferable for the photosensitive layer, and examples thereof include N-phenyl-1-naphthylamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N-diethyl-p-phenylenediamine, N -Phenyl-N'-ethyl-2-methyl-p-phenylenediamine, N-ethyl-N-hydroxyethyl-p-phenylenediamine, alkylated diphenylamine, N, N'-diphenyl-p-phenylenediamine, N, N '-Diallyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-phenylenediamine, 4,4'-dioctyl-diphenylamine, 4,4'-dioctyl-diphenylamine, 6-ethoxy-2,2 , 4-Trimethyl-1,2-dihydroquinoline, 2,2,4-trimethyl-1, - it can be exemplified dihydroquinoline, N- phenyl -β- naphthylamine, N, a N'- di-2-naphthyl -p- phenylenediamine.

  The phenolic antioxidant is 2.6-di-tert-butylphenol, 2.6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2.4-dimethyl-6-tert. -Butylphenol, 2.6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl propionate-β- (3.5-di-tert-butyl-4-hydroxyphenyl), α-tocopherol, monophenols such as β-tocopherol, n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate, 2.2′-methylenebis (6-tert-butyl-4) -Methylphenol), 4.4'-butylidene-bis- (3-methyl-6-tert-butyl) Enol), 4.4′-thiobis (6-tert-butyl-3-methylphenol), 1.1.3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1.3 .5-trimethyl-2.4.6-tris (3.5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3.5-di-tert-butyl-4-hydroxyphenyl) ) Propionate] Polyphenols such as methane are preferred, and one or more of them can be simultaneously contained in the photosensitive layer.

  Ultraviolet absorbers include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3.5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3.5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3.5 -Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3.5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5 ' -Tert-octylphenyl) benzotriazoles such as benzotriazole, phenyl salicylate, salicylic acid-p-te Salicylic acid series such as rt-butylphenyl and salicylic acid-p-octylphenyl are preferred, and benzotriazole ultraviolet absorbers are particularly preferred. One or more of the above antioxidants can be simultaneously contained in the photosensitive layer.

  The amount of phenolic antioxidant added to the electrophotographic photoreceptor used in the present invention is 3 to 20% by weight based on the binder resin, and the amount of amine antioxidant added to the binder resin. The content is preferably in the range of 3 to 20% by weight. On the other hand, the addition amount of the ultraviolet absorber is preferably 3 to 30% by weight with respect to the binder resin.

In addition, a thin film made of an organic thin film such as polyvinyl formal resin, polycarbonate resin, fluororesin, polyurethane resin, or silicone resin, or a siloxane structure formed from a hydrolyzate of a silane coupling agent is formed on the photosensitive layer. A surface protective layer may be provided as a film. In that case, the durability of the photoreceptor is improved, which is preferable. This surface protective layer may be provided in order to improve functions other than the durability improvement.
The thickness of the protective layer is suitably from 0.1 to 20 μm.

One of the features of the present invention is the material characteristics of the electrophotographic photoreceptor described below.
The electrophotographic photoreceptor used in the present invention preferably has a universal hardness of 150 to 175 N / mm ² on the surface of the photosensitive layer and an elastic power of 30 to less than 40%.
When the universal hardness is 175 N / mm ² or more, abnormal noise is generated at the contact point between the surface of the photosensitive layer and the cleaning blade when the photosensitive member is mounted and operated in an electrophotographic image forming apparatus. Similarly, abnormal noise occurs even when the elastic power is 40% or more.

On the other hand, when the universal hardness is smaller than 150 N / mm ² and the elastic power is smaller than 30%, a density abnormality due to filming occurs.

  In the electrophotographic photoreceptor used in the present invention, universal hardness and elastic work rate were measured on the surface of the photosensitive layer having a thickness of 24 μm after drying on an aluminum pipe.

  The universal hardness and elastic power of the photoconductor are Fischer Instruments H-100 (manufactured by Fischer Instruments), Vickers indenter, set load 9.8 mN, indentation depth 1 μm, measurement environment temperature 22 ° C., relative humidity It was measured under the condition of 55%. For universal hardness, the displacement of the indenter at the maximum load was expressed as the hardness value, and the elastic power was calculated from the graph of load-unload test.

A blade cleaning blade (hereinafter referred to as a cleaning blade) 83A (see FIG. 1) in the cleaning device 83 is obtained by attaching an elastic member made of a material such as a plate-like polyurethane to a support. It is configured to press contact with the surface.
The cleaning blade 83A can be appropriately selected within a range of hardness 65 to 75 ° (JISA hardness) and rebound resilience 30 to 50%. In order to increase the toner cleaning accuracy, it is effective to push the blade tip into the electrophotographic photosensitive member and increase the contact pressure of the blade. However, as described above, if the contact pressure of the cleaning blade is too large, the blade tip When the behavior increases and the chatter noise or vibration frequency of the blade resonates with the natural frequency of the photosensitive member, an unpleasant noise is generated.

The contact form of the blade to the electrophotographic photosensitive member to which the photosensitive drum corresponds corresponds to a forward direction with respect to the rotation direction of the electrophotographic photosensitive member and a counter direction.
From the standpoint of cleaning accuracy, the latter counter direction contact form is more preferable. The contact method in the counter direction that improves the cleaning accuracy raises the peak contact pressure of the blade to the photosensitive member when the photosensitive member rotates, causing an increase in the frictional force between the two. As a result, durability decreases due to an increase in the amount of abrasion of the photosensitive member, scratches on the electrophotographic photosensitive member occur, cleaning failure occurs due to turning up of the contact portion between the blade and the photosensitive member, and the blade is wound downstream in the photosensitive member. There is a risk of problems such as equipment stoppage or damage.

Next, the structure of the transfer apparatus, which is another feature of the present invention, will be described.
Another feature of the present invention is the arrangement of the transfer roller as a transfer member in addition to the material characteristics of the electrophotographic photoreceptor described above. This is intended to suppress the occurrence of scratches on the surface of the photosensitive drum 51 used as an electrophotographic photosensitive member. Details will be described below.

  FIG. 3 is a schematic diagram showing the configuration of the transfer device. The transfer device shown in FIG. 3 targets four-color images including the black image forming unit shown in FIG. A configuration in which the image forming units are juxtaposed along the extending direction of the intermediate transfer belt 58 as a transfer body is intended.

3, the image forming apparatus 1 is provided with an image forming unit having four photosensitive drums (latent image carriers) 51 to 54 arranged in series.
The intermediate transfer belt 58 is stretched by a belt driving roller 55 and a stretching roller 56 and a secondary transfer counter roller 57.

  Further, a cleaner unit 59 for collecting toner remaining on the intermediate transfer belt 58, a secondary transfer roller 60, a recording sheet S as a transfer material, a stretching roller 62, and a toner image on the photosensitive member are transferred to the intermediate transfer belt. Therefore, primary transfer rollers 67, 68, 69, and 70 corresponding to transfer members to which a bias having a polarity opposite to that of the toner can be applied are provided.

  The primary transfer rollers 67 to 70 used as transfer members are offset from positions other than the positions facing the photosensitive drums 51 to 54, and the intermediate transfer belt 58 can be partially mounted on the photosensitive drums 51 to 54. Is arranged. The offset in this case means that the primary transfer rollers 67 to 70 are not positioned on a line extending in the vertical direction from the axis of the photosensitive drums 51 to 54 in FIG. Then, it is introduced in advance that the offset arrangement may be referred to as an offset arrangement).

By using such a configuration, the primary transfer rollers 67 to 70 are offset toward the downstream side in the rotation direction of the photosensitive drums 51 to 54, so that the primary transfer rollers 67 to 70 are digged into the photosensitive member side.
When the primary transfer rollers 67 to 70 approach the photosensitive drums 51 to 54, the primary transfer rollers 67 to 70 are positioned on a line extending in the vertical direction from the axis of the photosensitive drums 51 to 54. Unlike the case where the photosensitive drums 51 to 54 are not directly collided with each other, the intermediate transfer belt 58 is in contact with the photosensitive drums 51 to 54 in a partially mounted state.
Therefore, the intermediate transfer belt 58 can form a transfer nip on the photoconductors 51 to 54 without the primary transfer rollers 67 to 70 directly applying a load to the photoconductors 51 to 54 via the intermediate transfer belt 58.

  As a result, when the primary transfer rollers 67 to 70 and the photosensitive drums 51 to 54 come into contact with each other, the intermediate transfer belt 58 is stretched so as to be partially mounted on the photosensitive drum. As a result, the impact force (transfer pressure) can be reduced as compared with the case where the primary transfer roller directly contacts, and the occurrence of rubbing scratches on the surface of the photoreceptor can be prevented. That is, the intermediate transfer belt 58 is pressed by the primary transfer rollers 67 to 70 so that a part of the extended portion reaches a part of the peripheral surface of the photosensitive drums 51 to 54 by the buffering force. The impact force on the surface is alleviated. However, it is a matter of course that the contact pressure after contact is a pressure at which the intermediate transfer belt 58 is not released from the peripheral surfaces of the photosensitive drums 51 to 54.

Further, the gap between the surfaces of the primary transfer rollers 67 to 70 and the surfaces of the photosensitive drums 51 to 54 is made larger than the thickness of the intermediate transfer belt 58.
That is, the surfaces of the primary transfer rollers 67 to 70 and the surfaces of the photosensitive drums 51 to 54 when the primary transfer rollers 67 to 70 are arranged on a line extending in the vertical direction from the axis of the photosensitive drums 51 to 54. The gap is made larger than the gap between the primary transfer rollers 67 to 70 by the amount offset to the downstream side in the rotation direction of the photosensitive drums 51 to 54. With such a gap setting, the intermediate transfer belt 58 is partially equipped with respect to the circumferential surface of the photosensitive drums 51 to 54 in a part in the extending direction.

  Thus, not only can the transfer nip between the intermediate transfer belt 58 and the photosensitive drums 51 to 54 be stabilized, but also the pressure on the intermediate transfer belt 58 can be reduced. There is an advantage that indentation (bite) due to the roller contact of the transfer belt 58 can be reduced.

On the other hand, the primary transfer rollers 57 to 60 contact and separate the intermediate transfer belt 58 with respect to the photosensitive drums 51 to 54 by contact / separation mechanisms 63, 64, 65 and 66. The contact / separation mechanisms 63, 64, 65, and 66 are provided for contacting and separating the primary transfer rollers 67 to 70 with respect to the intermediate transfer belt 58 according to the print mode.
The contact / separation mechanisms 63, 64, 65, and 66 are transfer means corresponding to the image carrier, that is, a black primary transfer roller (in FIG. 4, in the single color printing mode using only the endmost image carrier. The roller indicated by reference numeral 67 corresponds to a predetermined position for transferring the toner image on the photosensitive drum 51 as an image carrier, and the other transfer means is moved by the above contact / separation mechanism. The contact with the image carrier, which is a photosensitive drum, is released, and control is performed by a control unit (not shown) that makes the intermediate transfer belt 58 and the image carrier non-contact. The pressing pressure of the intermediate transfer belt against the image carrier is controlled by the amount of movement of the primary transfer roller.

In the present embodiment, the diameters of the photoconductors 51 to 54 are φ24, the pitch between the photoconductors is 53.4 mm, the driving roller 55 and the transfer rollers 67 to 70 have a shaft core metal diameter φ16, and the rubber layer has a thickness of 0.5 mm. Each is set, and the outer diameter is φ17.
Polycarbonate is used for the intermediate transfer belt 38, but polyimide, polyamideimide, PVDF, or the like can also be used.

The universal hardness of the intermediate transfer belt is preferably lower than the hardness of the surface of the photoreceptor, and is preferably 10 to 120 N / mm ² because the surface of the photoreceptor is finely scratched by rubbing during rotation. .

The universal hardness and elastic power of the intermediate transfer belt 58 are Fischer Instruments H-100 (manufactured by Fischer Instruments), Vickers indenter, set load 9.8 mN, indentation depth 10 μm, measurement environment temperature 22 ° C., Measurements were made at a relative humidity of 55%.
For universal hardness, the displacement of the indenter at the maximum load was expressed as the hardness value, and the elastic power was calculated from the graph of load-unload test.

  By arranging the transfer rollers in an offset manner, the hardness of the primary transfer rollers 67 to 70 can be set without being involved in the transfer failure. As described above, the offset amount and the biting amount can be arbitrarily set such that the gap between the photosensitive drums 51 to 54 and the primary transfer rollers 67 to 70 is larger than the thickness of the intermediate transfer belt 58.

  Since the transfer means, that is, the primary transfer rollers 67 to 70 are offset, it is possible to use a high-hardness material as the transfer means, increasing the degree of freedom of material, and using a low-cost member to improve transferability. Can be improved.

Therefore, a low-cost material such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, and indium can be selected as the primary transfer roller. However, it is not particularly limited to these metal materials, and rubber rollers such as EPDM and NBR can also be used.
The moving means of the contact / separation mechanisms 63, 64, 65, 66 are not particularly limited, but the transfer pressure is stabilized by pressurizing with a pressurizing means such as a spring, and the transfer nip is stabilized. There is.

  In addition, during non-image formation, the toner accumulated on the cleaning blade edge of the intermediate transfer can be released once by adding at least one operation in the direction opposite to the normal rotation direction, thereby reducing the amount of toner passing through the intermediate transfer cleaning blade. Can do. When the transfer residual toner passes through the cleaning blade of the intermediate transfer belt, the toner is locally adhered and solidified by the pressing pressure or transfer bias with the photoconductor, and finely adheres to the surface of the photoconductor at the rubbing portion with the photoconductor. It will be scratched.

In the above configuration, the cleaning performance of the intermediate transfer belt is improved, so that the margin for setting the intermediate transfer cleaning blade can be ensured, and the cleaning accuracy is relatively relaxed. The intermediate transfer belt can be designed with a low load, the surface of the intermediate transfer belt can be stabilized, and the photoconductor can be prevented from being finely scratched.
The amount of movement at the time of reverse rotation is not particularly defined, but it is preferably moved by at least an amount by which the damped toner layer is once released, and preferably moved by 1 mm or more.

  Using the transfer device described in this example, a printing durability test of 5000 sheets is performed in a normal temperature environment (23 ° C./50% Rh) with the photoconductor described below, and surface scratches and image quality of the photoconductor are confirmed. Went.

  The evaluation machine was a modified version of RICOH CX3000, the transfer device was arranged, and the photoconductor and toner were replaced with standard products, and experiments were conducted. The results are as shown in Table 1 below.

In the experiment, the charging condition is a contact charging method using a charging roll, a voltage is applied so that the surface potential of the photoreceptor can be uniformly charged to -500 V, and the development condition is an image of a non-magnetic one-component developing method using a contact roll. A forming device is used. The test was conducted at a system speed of 120 mm / sec. At the time of abnormal noise confirmation, confirmation is also performed in the half speed mode (60 mm / sec). The conditions used for this experiment are as follows.
"Image density"
○: Good, ×: Poor density.
"Filming"
The cleaning performance after running 5000 sheets was evaluated according to the following criteria.
A: Good, B: Filming but no effect on image quality, B: Minor image failure ×: Extremely bad.
"Abnormal noise"
Occurrence of abnormal noise after running 5000 sheets was evaluated according to the following criteria.
◎: Good, ○: Minor abnormal noise △: Unpleasant noise ×: Extremely loud noise
Example 1
"Create Toner"
Polyester resin A (softening point 131 ° C., AV value 25) 68 parts Polyester resin B (softening point 116 ° C., AV value 1.9) 32 parts Cyan Masterbatch (Pigment Blue 15: 3 50) 8 parts Carnauba wax ... 8 parts After the above toner material is sufficiently mixed with a Henschel mixer, the discharge part of the twin-screw extrusion kneader (PCM-30: manufactured by Ikekai Tekko Co., Ltd.) is removed. The resulting mixture was rolled to a thickness of 2 mm with a cooling press roller, cooled with a cooling belt, and then coarsely pulverized with a feather mill. Then, after pulverizing with a mechanical pulverizer (KTM: Kawasaki Heavy Industries, Ltd.) to an average particle size of 10-12 μm, and further pulverizing with a jet pulverizer (IDS: Nippon Pneumatic Industrial Co., Ltd.), Fine powder classification was performed using a rotor type classifier (Teplex type classifier type 100ATP: manufactured by Hosokawa Micron Corporation) to obtain a toner base A having a volume average particle diameter of 7.9 μm and an average circularity of 0.910. To 100 parts of this toner base A, 1 part of silica (RX200) was added and mixed with a Henschel mixer at a peripheral speed of 40 m / sec for 5 minutes to prepare a toner.
"Production of photoconductor"
On a cylindrical drum made of uncut aluminum with a diameter of 24 mm and a thickness of 1.0 mm, an alkyd resin (Beckolite M-6401-50 manufactured by Dainippon Ink and Chemicals) and an amino resin (Super Becamine G-821-60 Dainippon) Ink Chemical Industries Co., Ltd.) was mixed at a ratio of 65:35, and the mixed resin and titanium oxide (CR-EL Ishihara Sangyo Co., Ltd.) were mixed at a ratio of 1: 3. The film thickness was 5 μm. Next, 10 g of Y-type oxytitanium phthalocyanine powder having a maximum peak at an X-ray diffraction angle Cukα (2θ ± 0.2 degrees) of 27.3 degrees in FIG. 4 is added to glass beads and 1,3 dioxolane to 500 ml of polyvinyl butyral resin. (BX-1 Sekisui Chemical Co., Ltd.) Add 10g solution, disperse with sand mill disperser for 20 hours, filter the resulting dispersion, remove glass beads, and create coating solution for charge generation layer did. This was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm. Next, as the binder resin, a polycarbonate copolymer resin having a viscosity average molecular weight (Mv: 40,000) at a molar ratio of 90:10 based on the chemical structural formulas 1 and 2 and a chemical structural formula 3 are used. And a polycarbonate resin having a viscosity average molecular weight (Mv: 50,000), and a weight ratio of 90:10.

The charge transfer agent is a compound represented by the chemical structural formula 8.
The weight ratio of the binder resin to the charge transfer agent is 100: 60.
The binder resin and the charge transfer agent were dissolved in tetrahydrofuran to prepare a charge transfer layer coating solution. The substrate on which the charge generation layer was formed was dip-coated in the charge transfer layer coating solution, and dried at 130 ° C. for 60 minutes to form a charge transfer layer having a thickness of 24.0 μm, thereby producing an electrophotographic photoreceptor. .

The intermediate transfer belt 58 is made of polycarbonate, has a thickness of 0.2 mm, a universal hardness of 30.5 N / mm ² , the transfer roller has a shaft core metal diameter of φ16, a rubber layer has a thickness of 0.5 mm, and an outer diameter of φ17. . The offset amount was 7 mm and was brought into contact with the photoconductor.
(Example 2)
The experiment was performed in the same manner as in Example 1 except that the weight ratio of the polycarbonate copolymer resin used in Example 1 to the polycarbonate resin type was 60:40.
Example 3
Experiments were conducted in the same manner as in Example 1 except that the polycarbonate copolymer used in Example 1 was changed to chemical structural formulas 1 and 2 and the molar ratio was changed to 80:20.
Example 4
The experiment was performed in the same manner as in Example 1 except that instead of the charge transfer agent used in Example 1, the charge transfer agent represented by Chemical Structural Formula 20 was used.
(Example 5)
The experiment was conducted in the same manner as in Example 1 except that the charge transfer agent represented by chemical structural formula 21 was used instead of the charge transfer agent used in Example 1.
(Example 6)
The experiment was performed in the same manner as in Example 1 except that instead of the charge transfer agent used in Example 1, the charge transfer agent represented by the chemical structural formula 22 was used.
(Example 7)
In Example 1, in addition to the binder resin and the charge transfer material, 2.6-di-tert-butylphenol and N-phenyl-1-naphthylamine as antioxidants are each 5% by weight with respect to the charge transfer agent, and UV absorption An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the agent 2- (5-methyl-2-hydroxyphenyl) benzotriazole was added in an amount of 5% by weight based on the charge transfer agent.
(Example 8)
In Example 1, an experiment was performed in the same manner as in Example 1 except that the transfer roller was a SUS roller.
Example 9
In Example 1, an experiment was performed in the same manner as in Example 1 except that an intermediate transfer belt reverse rotation mode with a moving amount of 3 mm was set for every 100 sheets during the printing durability test.
(Comparative Example 1)
An experiment was conducted in the same manner as in Example 1 except that Chemical Structural Formula 19 was used instead of Chemical Structural Formula 1 of the polycarbonate copolymer resin used in Example 1.

(Comparative Example 2)
The experiment was performed in the same manner as in Example 7 except that the weight ratio of the polycarbonate copolymer resin used in Example 7 to the polycarbonate resin was 50:50.
(Comparative Example 3)
An electrophotographic photoreceptor was prepared in the same manner as in Example 7 except that the weight ratio of the polycarbonate copolymer resin used in Example 7 to the polycarbonate resin was 100: 0.
(Comparative Example 4)
An electrophotographic photoreceptor was prepared in the same manner as in Example 7 except that the charge transfer agent (chemical structural formula 20) was used instead of the charge transfer agent (chemical structural formula 8) used in Example 7.

(Comparative Example 5)
Instead of the Y-type oxytitanyl phthalocyanine used in Example 7, the α-type oxytitanyl phthalocyanine represented by the X-ray diffraction angle Cukα (2θ ± 0.2 degrees) in FIG. 5 was used. Otherwise, an electrophotographic photoreceptor was prepared in the same manner as in Example 7.
(Comparative Example 6)
The experiment was performed in the same manner as in Example 1 except that the offset amount of the intermediate transfer roll was set to 15 mm in Example 1.
(Comparative Example 7)
The experiment was performed in the same manner as in Example 1 except that the offset amount of the intermediate transfer roll was set to 0 mm in Example 1.
(Comparative Example 8)
The experiment was performed in the same manner as in Example 1 except that the offset amount of the intermediate transfer roll was set to 5 mm in Example 1.
(Comparative Example 9)
The experiment was performed in the same manner as in Example 1 except that the offset amount of the intermediate transfer roll was 3 mm in Example 1.
(Comparative Example 10)
An experiment was performed in the same manner as in Example 1 except that the offset amount of the intermediate transfer roll was set to 10 mm in Example 1.
(Comparative Example 11)
An electrophotographic photoreceptor was prepared in the same manner as in Example 7 except that the weight ratio of the polycarbonate copolymer resin used in Example 7 to the polycarbonate resin was 95: 5.

  The experimental results under the above conditions are as shown in Table 1 below.

1 is a schematic diagram illustrating an image forming apparatus for describing an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a configuration of a photoreceptor used in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram for explaining a configuration of a transfer unit used in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram showing an X-ray diffraction angle Cuka (2θ ± 0.2 degrees) for one component of a compound used for a photoreceptor. FIG. 3 is a diagram showing an X-ray diffraction angle Cuka (2θ ± 0.2 degrees) for other components of a compound used for a photoreceptor. 1 is a schematic diagram for explaining a configuration of a tandem type image forming apparatus that is one type of image forming apparatus. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 51-54 Photosensitive drum 51A Photosensitive layer 67-70 Primary transfer roller 80 Charging apparatus 81 Writing apparatus 82 Developing apparatus 83 Cleaning apparatus 83A Cleaning blade

Claims (12)

A developing device for processing a visible image of an electrostatic latent image formed on a uniformly charged latent image carrier using a toner containing non-magnetic single component and wax, and a developed toner image A transfer device for transferring the toner to the transfer member, and a cleaning device for removing untransferred toner on the latent image carrier after passing through the transfer device, the belt being movable in contact with the latent image carrier. And a transfer member capable of applying a bias to transfer a toner image to the belt body, and the cleaning device uses an elastic blade that contacts the surface of the latent image carrier. In the forming device,
The transfer member is offset at a position other than the position facing the latent image carrier in the moving direction of the belt body, and is disposed at a position where the belt body can be partially mounted on the latent image carrier.
As the latent image carrier, an electrophotographic photosensitive member is used, and the electrophotographic photosensitive member includes at least a binder resin in the photosensitive layer.

and

A polycarbonate copolymer resin A containing a repeating unit represented by:

In which the weight ratio of the polycarbonate copolymer resin A and the polycarbonate resin B is set in the range of 60:40 to 90:10, and the universal hardness of the surface is image forming apparatus characterized by 150~175N / ^m m ² and elastic work ratio is set to 30-40%.   The image forming apparatus according to claim 1, wherein a transfer roller is used as the transfer member, and a distance at which an axial center of the transfer member is offset in a moving direction of the belt body is set to 5 to 10 mm. .   2. The image forming apparatus according to claim 1, wherein in the electrophotographic photoreceptor, the charge generating agent in the photosensitive layer is Y-type oxytitanium phthalocyanine. The electrophotographic photoreceptor has a charge transfer agent in the photosensitive layer.

(In the formula, R _{1 to} R ₃ are each independently hydrogen, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a substituted or unsubstituted group having 6 to 12 carbon atoms. Represents an aryl group.)
The image forming apparatus according to claim 1, wherein the image forming apparatus is a distyryl charge transfer agent represented by the formula:   The electrophotographic photoreceptor includes a phenol-based antioxidant, an amine-based antioxidant, and a benzotriazole-based ultraviolet absorber as additives contained in the photosensitive layer. The image forming apparatus according to any one of the above.   6. The electrophotographic photosensitive member uses tetrahydrofuran as a solvent for dissolving the components of the photosensitive layer and forming the photosensitive layer. The image forming apparatus described in 1. The image forming apparatus according to claim 1, wherein the belt body has a universal hardness of 10 to 120 N / mm ² .   The image forming apparatus according to claim 1, wherein a transfer roller used for the transfer member is made of metal.   The transfer roller is provided so as to be able to come into contact with and separate from the belt body, and sets a state in which the belt body is fitted to a part of the peripheral surface of the latent image carrier when abutting on the belt body. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The transfer roll is provided so as to be able to come in contact with and separate from the belt body in each of the image forming portions of a plurality of color images. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as described above.   9. The distance between the surface of the transfer roll and the surface of the image carrier on the line connecting the latent image carrier and the axial center of the transfer roller is set to be larger than the thickness of the transfer belt. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the movement drive member used for the belt body is movable in a direction opposite to that during image formation during non-image formation.

Images