JP2008033067A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of securing excellent image characteristic while restraining the adhesion of toner to a drum. <P>SOLUTION: The image forming apparatus is equipped with a cleaning blade 6a scraping off residual toner on the surface of a photoreceptor drum 1, and a cleaning roller 6b provided on a more upstream side in the rotating direction of the photoreceptor drum 1 than the cleaning blade 6a and rubbing on the surface of the photoreceptor drum 1. Mixed material 10 composed by adding zinc stearate to resin for fixation that is the raw material of the toner is applied to the cleaning roller 6b when the photoreceptor drum 1 is new. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile.

  In a conventional general image forming apparatus, an image forming operation as described below is performed. As the photosensitive drum rotates in one direction, first, the surface of the photosensitive drum is uniformly charged to a predetermined potential by a charger. Next, an electrostatic latent image is formed on the surface of the photosensitive drum by irradiation light based on image information from the exposure device, and a toner image is formed (developed) by adsorbing toner to the electrostatic latent image by the developing device. The Subsequently, the toner image on the photosensitive drum is transferred onto a sheet such as paper by a transfer device such as a transfer roller. Thereafter, the sheet is conveyed to a fixing device composed of a pair of rollers, and after the toner image is fixed on the sheet by heating and pressing with the fixing device, the sheet is discharged to the outside. On the other hand, the residual toner remaining on the surface of the photosensitive drum after transfer is scraped off by a cleaning blade, and the surface of the photosensitive drum is uniformly discharged by a static eliminator as necessary. Such a series of operations is repeated.

  In recent image forming apparatuses, a cleaning roller that rotates in one direction while being in contact with the surface of the photosensitive drum is provided between the transfer unit and the cleaning blade, and the cleaning roller is provided on the surface of the photosensitive drum. By rubbing, the surface of the photosensitive drum is polished. At that time, the toner from the developing device contains an abrasive in advance, and the toner containing the abrasive is used for polishing the photosensitive drum by the cleaning roller. That is, among the toner-containing toner adsorbed on the surface of the photosensitive drum as a toner image, the toner remaining on the surface of the photosensitive drum after transfer is supplied to the cleaning roller as it is or scraped off with a blade and cleaned. As a result, it is supplied to the cleaning roller by being dropped onto the roller.

  By the way, in such an image forming apparatus, particularly in the initial stage of using the manufactured image forming apparatus for the first time, the drum adheres to the surface of the photosensitive drum and the fragments adhere to the surface of the photosensitive drum. Is likely to occur. This is because the photosensitive drum and the cleaning blade are new, so that the cleaning blade is strongly pressed against the surface of the photosensitive drum, and the two are not familiar with each other. When the drum adheres, the quality of the image transferred to the paper is deteriorated as a result. However, the drum adhesion occurs remarkably at the initial stage of use and does not occur as the image forming apparatus is used. This is because the cleaning blade is appropriately worn and pressed against the surface of the photosensitive drum with an appropriate pressure, and both become familiar.

Therefore, in order to prevent the drum from adhering, conventionally, a lubricant is applied in advance to the surface of the photosensitive drum or a cleaning blade in contact with the surface at the manufacturing stage of the image forming apparatus, or a lubricant is applied to the toner from the developing device. (For example, refer to Patent Document 1). Zinc stearate is used as the lubricant. In this way, the lubricant promotes the lubricity between the surface of the photosensitive drum and the cleaning blade, so that the occurrence of drum adhesion can be suppressed.
JP 2000-172120 A

  However, if a lubricant is applied to the photosensitive drum or cleaning blade, the occurrence of drum adhesion can be suppressed in the initial stage of use, but it can be applied directly to the surface of the photosensitive drum or used. Since there is a large amount of lubricant due to slipping through the cleaning blade according to the actual condition, the presence of the lubricant will actually be damaged and image characteristics such as image flow, fogging, and image density reduction will occur. Resulting in. This is because, on the surface of the photosensitive drum, the charging characteristic is mainly deteriorated in a portion where zinc stearate as a lubricant is present.

  Furthermore, when a lubricant is mixed into the toner from the developing unit, although the occurrence of drum adhesion can be suppressed regardless of the stage of use, since the lubricant is continuously supplied together with the toner according to use, in the long term, Lubricant accumulates on the surface of the photosensitive drum, and image characteristics such as image flow, fogging, and a decrease in image density also occur.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of ensuring good image characteristics while suppressing the occurrence of drum adhesion.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a photosensitive drum that rotates in one direction, an exposure device that exposes the surface of the photosensitive drum to form an electrostatic latent image, and an electrostatic latent image. A developing device that forms a toner image by attaching toner, a transfer device that transfers the toner image to a supplied sheet, and a cleaning device that cleans the surface of the photosensitive drum after transfer, An image forming apparatus comprising: a cleaning blade that scrapes residual toner on the surface of the photosensitive drum; and a cleaning roller that is provided upstream of the cleaning blade in the rotational direction of the photosensitive drum and rubs the surface of the photosensitive drum. When the photosensitive drum is new, the cleaning roller is coated with a mixed material obtained by adding zinc stearate to a fixing resin that is a raw material of the toner. It is.

  Thus, in the initial stage of use, the mixed material is supplied from the cleaning roller to the surfaces of the photosensitive drums that are in contact with each other, and the zinc stearate in the mixed material promotes the lubricity between the surface of the photosensitive drum and the cleaning blade. Therefore, the occurrence of drum adhesion can be suppressed. In addition, zinc stearate in the mixed material is removed from the surface of the photosensitive drum together with the fixing resin by scraping with a cleaning blade, so that image characteristics such as image flow, fog, and image density decrease occur. Can also be suppressed.

  Here, with respect to the mixed material, the amount of zinc stearate added to the fixing resin is preferably 10 to 35 [wt%].

  According to the image forming apparatus of the present invention, good image characteristics can be secured while suppressing the occurrence of drum adhesion.

  Hereinafter, an embodiment of an image forming apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of an image forming apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus generally includes a photosensitive drum 1 that is axially driven in one direction, a charger 2 that uniformly charges the surface of the photosensitive drum 1 to a predetermined potential, An exposure device 3 that exposes the surface of the photosensitive drum 1 charged by the charger 2 to form an electrostatic latent image based on image information, and attracts toner to the electrostatic latent image formed by the exposure device 3 A developing device 4 for forming (developing) a toner image, a transfer device 5 including a transfer roller for transferring the toner image formed by the developing device 4 to the sheet P, and the photosensitive drum 1 after the transfer. A cleaning device 6 for cleaning the surface and a fixing device 7 composed of a pair of rollers for fixing the toner image transferred on the sheet P by heating and pressurizing are provided. All of these operations are controlled by a control unit (not shown).

  Here, the photosensitive drum 1 is formed, for example, by forming an amorphous silicon photosensitive layer on the surface of a base tube made of aluminum or the like. The exposure unit 3 exposes the surface of the charged photosensitive drum 1 with light from a laser diode or an LED array, and forms an electrostatic latent image based on image information that is an object of image formation on the sheet P. Take on.

  The developing device 4 stores toner. As the toner here, as will be described in detail later, a general toner in which a colorant and various additives are dispersed in a fixing resin as a raw material is used, and an abrasive is also mixed. Further, the developing device 4 includes a stirring roller (not shown) for stirring the toner, a developing sleeve 4a that is disposed opposite to the photosensitive drum 1 and directly supplies the toner to the photosensitive drum 1, and a toner on the developing sleeve 4a. A cutting plate 4b for adjusting the thickness uniformly is provided. At the time of development, a bias is applied to the developing sleeve 4a, whereby toner is attracted to the electrostatic latent image on the photosensitive drum 1, and the toner image is developed.

  The transfer device 5 is applied with a bias having a polarity opposite to that of the toner at the time of transfer, whereby the toner image is transferred onto the sheet P supplied to the photosensitive drum 1.

  The cleaning device 6 mainly includes a cleaning blade 6a and a cleaning roller 6b. The cleaning blade 6 a extends along the photosensitive drum 1 and is fixed in a state of being pressed against the surface of the photosensitive drum 1, and scrapes residual toner remaining on the surface of the photosensitive drum 1 after transfer. Take and remove. For example, urethane rubber is suitable as the cleaning blade 6a.

  The cleaning roller 6b is a porous elastic material such as foamed urethane rubber, and is upstream of the cleaning blade 6a in the rotation direction of the photosensitive drum 1, that is, between the transfer device 5 and the cleaning blade 6a. Just below the cleaning blade 6a, it is disposed in contact with the photosensitive drum 1 in a contact state. By rotating in one direction, the surface of the photosensitive drum 1 is rubbed together with the rotation of the photosensitive drum 1. During the image forming operation, the toner-containing toner remaining on the photosensitive drum 1 after the transfer is mainly scraped off by the cleaning blade 6a and dropped onto the cleaning roller 6b as a result. It will be supplied. Then, the surface of the photosensitive drum 1 is continuously polished by the cleaning roller 6b supplied with the abrasive. Note that the rotation direction of the cleaning roller 6 b is opposite to the rotation direction of the photosensitive drum 1 so that the surface of the photosensitive drum 1 can be effectively polished, and the rotational speed thereof is 1.2 of that of the photosensitive drum 1. It is preferable to make it about twice.

  Further, the mixed material 10 is applied to the cleaning roller 6b in advance at the manufacturing stage of the image forming apparatus over the entire outer periphery thereof. That is, the mixed material 10 is applied to the cleaning roller 6b when the photosensitive drum 1 (including the cleaning blade 6a) is new. Although the details will be described later, the mixed material 10 here is obtained by adding a predetermined amount of zinc stearate to a fixing resin which is a raw material of the toner. In the initial stage of use, the mixed material 10 is supplied from the cleaning roller 6b to the surface of the photosensitive drum 1 in contact with each other, and the surface of the photosensitive drum 1 and the cleaning blade 6a are lubricated by the zinc stearate in the mixed material 10. Therefore, the occurrence of drum adhesion can be suppressed. Further, since the fixing material, which is a raw material of the toner, is contained in the mixed material 10, the zinc stearate in the mixed material 10 is scraped off by the cleaning blade 6a and the photosensitive drum 1 together with the fixing resin. Removed from the surface. Therefore, it is possible to suppress the occurrence of image characteristic defects such as image flow, fogging, and a decrease in image density. Such a situation is derived from the following evaluation test.

  Next, details of the toner and the mixed material 10 and an evaluation test performed by the image forming apparatus of the present embodiment will be described below.

  First, as the fixing resin, for example, styrene polymer, acrylic polymer, styrene-acrylic polymer, olefin polymer such as chlorinated polystyrene, polypropylene, ionomer, polyvinyl chloride, polyester resin, Polyamide, polyurethane, epoxy resin, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, phenol resin, rosin modified phenol resin, xylene resin, rosin modified maleic acid resin, rosin ester, etc. A coalescence, a styrene-acrylic polymer, and a polyester resin are preferable. Of these, examples of the styrene polymer and the styrene-acrylic polymer include styrene homopolymers and copolymers of styrene and other monomers.

  Here, as other monomers copolymerizable with styrene, for example, p-chlorostyrene; vinyl naphthalene; ethylene unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene; vinyl chloride, vinyl bromide, Vinyl halides such as vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate (Meth) acrylic acid esters such as n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate; acrylonitrile, methacrylonitrile, Such as acrylamide Acrylic acid derivatives of: vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N -N-vinyl compounds such as vinylpyrrolidene. These copolymerization monomers can be copolymerized with styrene either alone or in combination of two or more.

  Examples of the polyester resin include those obtained by polycondensation of a polyvalent carboxylic acid component and a polyhydric alcohol component. Of these, examples of the polyvalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, and sebacic acid. Divalent carboxylic acids such as azelaic acid and malonic acid; n-butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, alkyl or alkenyl esters of divalent carboxylic acids such as n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid; 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzene Tricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4- Phthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclo Hexatricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, trivalent or higher carboxylic acid such as empole trimer acid, and the like. In addition, anhydrides of these polyvalent carboxylic acids are also used.

  On the other hand, examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butene. Diols such as diol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and bisphenol A Bisphenols such as hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pen Erythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butane Examples include triol or higher polyhydric alcohols such as triol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

  Next, as the colorant, pigments of various colors that match the color of the desired toner are used. Here, as the black pigment, magnetite, ferrite powder, carbon black, acetylene black, lamp black, aniline black and the like are suitable.

  Yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, naples yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline yellow lake, permanent yellow NCG, tartrazine lake and the like are suitable.

  As the orange pigment, reddish yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange GK and the like are suitable.

  Examples of red pigments include bengara, cadmium red, red lead, mercury cadmium sulfide, permanent red 4R, risor red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, and alizarin lake. Brilliant carmine 3B and the like are suitable.

  As the purple pigment, manganese purple, fast violet B, methyl violet lake and the like are suitable.

  As the blue pigment, bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indanthrene blue BC and the like are suitable.

  As the green pigment, chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G and the like are preferable.

  In the case of a non-magnetic toner, the addition amount of the colorant is preferably about 1 to 20 parts by weight, more preferably about 2 to 8 parts by weight with respect to 100 parts by weight of the fixing resin. On the other hand, in the case of magnetic toner, about 50 to 200 parts by weight is preferable with respect to 100 parts by weight of the fixing resin. In the case of magnetic toner, the colorant is magnetic powder.

  Next, representative examples of additives other than the colorant include charge control agents and offset preventing agents. Here, the charge control agent is for controlling the frictional charging characteristics of the toner, and a charge control agent for controlling positive charge or a charge control agent for controlling negative charge is used according to the charge polarity of the toner. Among these, as a charge control agent for positive charge control, an organic compound having a basic nitrogen atom, for example, a basic dye, an aminopyrine, a pyrimidine compound, a polynuclear polyamino compound, an aminosilane, or the like, or a surface treatment with each of the above compounds A filler etc. are mentioned. On the other hand, charge control agents for controlling negative charges include oil-soluble dyes such as nigrosine base, oil black, Bontron S, and spiron black; charge control resins such as styrene-styrene sulfonic acid copolymer; And the like (eg metal alkylsalicylate chelate), metal complex dyes, fatty acid metal soaps, resin acid soaps, naphthenic acid metal salts and the like. The addition amount of the charge control agent is preferably about 0.1 to 10 parts by weight, more preferably about 0.5 to 8 parts by weight with respect to 100 parts by weight of the fixing resin.

  The offset preventive agent is blended in order to impart an offset preventing effect to the toner. Examples of the offset preventive agent include aliphatic hydrocarbons, aliphatic metal salts, higher fatty acids, fatty acid esters or partially saponified products thereof, silicone oil, and various waxes. Among these, aliphatic hydrocarbons having a weight average molecular weight of about 1000 to 10,000 are preferable. Specifically, one or a combination of two or more of low molecular weight polypropylene, low molecular weight polyethylene, paraffin wax, a low molecular weight olefin polymer composed of olefin units having 4 or more carbon atoms, silicone oil and the like are suitable. The addition amount of the offset inhibitor is preferably about 0.1 to 10 parts by weight, more preferably about 0.5 to 8 parts by weight with respect to 100 parts by weight of the fixing resin. In addition, you may mix | blend various additives, such as a stabilizer, in a suitable ratio.

  Examples of the abrasive mixed in the toner include silica, alumina, titanium oxide, magnetite, and strontium titanate.

  The toner is obtained through a mixing process, a mixing process, a coarse pulverization process, a fine pulverization process, a classification process, and an external addition process according to a general pulverization method. It can also be obtained by a chemical production method such as a polymerization method. Regarding the particle diameter of the toner, the volume-based center particle diameter (volume average particle diameter) is preferably about 4 to 12 μm, more preferably about 6 to 10 μm.

  The evaluation test was performed as follows.

  First, a fixing resin as a raw material for toner was obtained as follows. In a reaction vessel equipped with a thermometer, a stirrer, and a nitrogen introduction tube, 300 parts by weight of xylene was placed, and under a nitrogen stream, a mixed monomer of 845 parts by weight of styrene and 155 parts by weight of n-butyl acrylate, and di- Using a mixed solution of 8.5 parts by weight of tert-butyl peroxide (polymerization initiator) and 125 parts by weight of xylene, the solution is added dropwise at 170 ° C. over 3 hours. After the dropping, the reaction is carried out at 170 ° C. for 1 hour to complete the polymerization. Thereafter, the solvent was removed to obtain a fixing resin.

  When producing magnetic toner, 49 parts by weight of the fixing resin obtained as described above, 45 parts by weight of magnetic powder as a colorant of a desired color, 3 parts by weight of wax as a release agent, and as a positive charge control agent After mixing 3 parts by weight of a quaternary ammonium salt in a mixer, the mixture is melt kneaded with a twin screw extruder, then cooled, and coarsely pulverized with a hammer mill. Further finely pulverized by a mechanical pulverizer and classified by an airflow classifier to obtain a magnetic toner having a volume average particle diameter of 8.0 μm.

  On the other hand, when producing a non-magnetic toner, 80 parts by weight of the fixing resin obtained as described above, 20 parts by weight of 2-ethylhexyl methacrylate, 5 parts by weight of a colorant of a desired color, 3 parts by weight of low molecular weight polypropylene, charge After a mixed solution of 2 parts by weight of a control agent and 1 part by weight of divinylbenzene (crosslinking agent) is sufficiently dispersed by a ball mill, 2 of 2,2-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator is added. Add parts by weight. It is added to 400 parts by weight of ion-exchanged water, and further 5 parts by weight of calcium triphosphate and 0.1 part by weight of sodium dodecylbenzenesulfonate are added as a suspension stabilizer, and the emulsion is dispersed at 45 rpm at 5000 rpm using an emulsifier / disperser. The mixture is stirred for one minute and polymerized at 70 ° C. and 100 rpm for 10 hours under a nitrogen atmosphere. Thereafter, acid washing is performed to remove tricalcium phosphate, and a dispersion liquid in which toner having a volume average particle diameter of 7.5 μm is dispersed is obtained. This dispersion was filtered, washed and dried to obtain a toner. The resulting toner particles had a sphericity of 0.975. In the case of a non-magnetic toner, a toner having a smaller particle diameter is obtained by stirring for 60 minutes at 6000 rpm using an emulsifier / disperser. Even if the amount of tricalcium phosphate is increased, the toner has a smaller particle diameter.

  The toner thus obtained was mixed with an abrasive such as titanium oxide or silica using a mixer to obtain a toner containing an abrasive. The toner containing the abrasive was loaded into the developing device 4 of the test image forming apparatus.

  On the other hand, a predetermined amount of zinc stearate was added to and mixed with the fixing resin obtained as described above using a mixer to obtain a mixed material 10. Here, for the evaluation test, eight kinds of mixed materials 10 having different amounts of zinc stearate added to the fixing resin were prepared. The amount of zinc stearate added to the fixing resin of each mixed material 10 is 2.5, 8, 10, 20, 30, 35, 37, and 50 [% by weight], respectively.

  Then, for each of the mixed materials 10 with different amounts of zinc stearate added, a new photoconductor unit was prepared with the photosensitive drum 1 and the cleaning blade 6a, and the mixed material 10 was applied to the cleaning roller 6b of each photoconductor unit. The photoreceptor unit is mounted on a test image forming apparatus, and an image forming operation is performed about a dozen times assuming an initial stage of use in a normal temperature and humidity environment (20 ° C., 65% RH). An output paper on which a standard pattern image for evaluation was printed was obtained. Such a test was performed for each photosensitive member unit, that is, for each of the mixed materials 10 having different zinc stearate addition amounts.

  With respect to the image on the output paper, the image characteristics relating to image density (ID), fog (FD), and image flow were evaluated in three levels: “excellent”, “normal”, and “impossible”. The image density was measured using a reflection densitometer (manufactured by Gretag Macbeth Co., Ltd.), “excellent” at 1.30 or more, “normal” at 1.20 or more but less than 1.30, “impossible” at less than 1.20. It was. As for fog, it is measured using a reflection densitometer (manufactured by Tokyo Denshoku Co., Ltd.). It was. Regarding the image flow, it is judged visually, "excellent" when the image flow has not occurred, "normal" when the image flow has occurred but the image content can be recognized, "image" has occurred and the image content has When it cannot be recognized, it was set as “impossible”

  Further, regarding the drum adhesion, the photoreceptor drum 1 after the test is visually determined, and “excellent” when there is no deposit and there is no unevenness on the drum surface, and “normal” when there is deposit but can be removed. In the case where there is an adhering substance and it is completely fixed, the evaluation was made in three stages, “impossible”.

The results are summarized in Table 1 below.

  From Table 1 above, it can be seen that when the amount of zinc stearate added to the fixing resin is 37% by weight or more, defects in image characteristics such as image flow, fogging, and image density decrease remarkably occur. Further, it can be seen that when the amount of zinc stearate added to the fixing resin is 8% by weight or less, drum adhesion is remarkably generated. Accordingly, when the amount of zinc stearate added is in the range of 10 to 35% by weight, the occurrence of drum adhesion can be suppressed and good image characteristics can be ensured. That is, if the amount of zinc stearate added is within the range, the lubricity between the surface of the photosensitive drum 1 and the cleaning blade 6a is sufficiently promoted by the zinc stearate, and the photosensitive drum is scraped off by the cleaning blade 6a. It can be said that zinc stearate is sufficiently removed from the surface of 1 and that zinc stearate does not harm. Then, with respect to the mixed material 10, it is preferable that the amount of zinc stearate added to the fixing resin is 10 to 35 [% by weight].

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention is useful for an image forming apparatus including a cleaning roller for a photosensitive drum.

1 is a cross-sectional view illustrating a main part of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Cleaning device 6a Cleaning blade 6b Cleaning roller 7 Fixing device 10 Mixing material

Claims (2)

A photosensitive drum that rotates in one direction, an exposure device that exposes the surface of the photosensitive drum to form an electrostatic latent image, a developing device that forms a toner image by attaching toner to the electrostatic latent image, and a supply A transfer device that transfers the toner image to the sheet that has been transferred, and a cleaning device that cleans the surface of the photosensitive drum after transfer, and a cleaning blade that scrapes off residual toner on the surface of the photosensitive drum as a cleaning device, A cleaning roller that is provided upstream of the cleaning blade in the rotational direction of the photosensitive drum and rubs the surface of the photosensitive drum;
An image forming apparatus, wherein a cleaning material when a photosensitive drum is new is coated with a mixed material obtained by adding zinc stearate to a fixing resin which is a raw material of toner.   The image forming apparatus according to claim 1, wherein the amount of zinc stearate added to the fixing resin is 10 to 35 [wt%] with respect to the mixed material.

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