JP6052012B2 - Packing method for cylindrical electrophotographic photosensitive member - Google Patents

Description

  The present invention relates to a method for packing an electrophotographic photosensitive member used for a copying machine, a printer, and the like, a packed electrophotographic photosensitive member, and an image forming apparatus.

C. F. The electrophotographic technology invented by Carlson is not limited to the field of copiers, because it can provide images with immediacy, high quality, and high storage stability. Has also become widespread and shows a huge spread.
An electrophotographic photoreceptor is most often used in which a photosensitive layer of an organic photoconductive material is formed on the surface of a cylindrical substrate. This photosensitive layer plays an important role in the electrophotographic process, such as converting an optical image into an electrostatic latent image. Therefore, in the photoreceptor on which the photosensitive layer is formed, the photosensitive layer is mechanically damaged. In order to protect against deterioration due to strong light, adhesion of contaminants, etc., a packaging method is generally employed in which the outer surface of the photoreceptor is covered with a protective sheet.

Black quality paper is often used as the material of the protective sheet, and a synthetic polymer compound such as non-conductive or conductive synthetic resin film may be used. In addition, it is common to use the adhesive tape which has an adhesive agent on the single side | surface for fixation of the wound protection sheet. FIG. 1 is a perspective view showing an example of a method for packing an electrophotographic photoreceptor.
An outline of the packing method will be described. First, a peripheral side 2a that is longer than the outer peripheral length of the photoconductor 1, and a width side 2b that is longer than the width of the photosensitive layer formed on the outer surface of the photoconductor 1 and shorter than the cylindrical length of the photoconductor 1. Are prepared so that the axial direction of the photosensitive member 1 and the width side 2b of the protective sheet 2 are parallel to each other.

  Next, the protective sheet 2 is wound around the outer surface of the photoconductor 1 so as not to be slack, and disposed so that the outer surface of the winding portion 2d overlaps the inner surface of the winding end portion 2c. Finally, using the adhesive tape 3 of a predetermined size provided with a peeling part 3a having an adhesive 3b on one side and no adhesive being attached to one end, the adhesive tape 3 and the outer surface of the winding end 2c are joined together. The side having no peeling part 3a is adhered to the outer surface side of the winding end part 2c so that the side having the peeling part 3a is attached to the outer surface side of the winding part 2d so as to be bridged almost evenly on the outer surface of 2d. The protective sheet 2 that is stuck and wound around the photoreceptor 1 is fixed.

  At this time, studies have been made to solve problems such as the adhesive of the adhesive tape adhering to the surface of the photoreceptor (for example, Patent Document 1 and Patent Document 2). On the other hand, no particular attention has been paid to the problem of damaging the surface of the contact photosensitive member such as a protective sheet or a finger. It was common to solve the problem by devising the surface composition of the body (Patent Document 3). For the problem of static electricity due to friction with the protective sheet, it is conceivable to increase the conductivity of the protective sheet, but it is rarely detected as an actual effect, and in reality it should be handled with care. It is common to prevent the generation of static electricity in the form.

  Further, it has been known that the image forming apparatus can suppress the wear amount by reducing the surface potential of the dark part of the photosensitive member.

JP-A-10-72075 JP-A-10-167340 JP2008-145737

When a cylindrical electrophotographic photosensitive member is mounted on an electrophotographic apparatus or electrophotographic cartridge such as a copying machine, printer, or facsimile machine, when removing the protective sheet, static electricity due to frictional charging between the surface of the photosensitive member and the protective sheet is the cause. Image defects (electrostatic memory) may appear, and there is a concern that the print quality may be deteriorated when the photoconductor is used.
In particular, it has been found that the electrostatic memory is actually detected as an image when the absolute value of the dark portion surface potential of the photoreceptor is small.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a packing method using a protective sheet that does not generate an electrostatic memory when the protective sheet is removed when the photoreceptor is mounted on a machine or the like. And an electrophotographic photoreceptor packaged by the method.

The present inventor has found that the electrostatic resistance is not detected as an image defect only when the absolute value of the dark portion surface potential of the photosensitive member is low, and thus the surface resistance of the protective sheet of the photosensitive layer may be reduced. The present invention has been reached.
That is, the gist of the present invention resides in the following (1 ) .
(1) A packing method for packing a photosensitive member charged with a protective sheet so that the absolute value of the dark portion surface potential of the cylindrical electrophotographic photosensitive member is 450 V or less,
Characterized by using the protective sheet the surface resistance of 10 ⁵ Ω / cm ² or less at 10 ³ Ω / cm ² or more, packing how of the cylindrical electrophotographic photosensitive member.

  According to the present invention, when the protective sheet is removed from the photoconductor mounted on the image forming apparatus in which the absolute value of the dark portion surface potential of the photoconductor is 450 V or less, the generation of static electricity is suppressed and the image quality of the memory or the like is deteriorated. There can be provided a packing method using a non-protective sheet, and an electrophotographic photosensitive member packed by the method.

It is the schematic which shows one embodiment of the packing method of this invention. It is a typical perspective view of the photoconductor packed by the method of the present invention. FIG. 2 is a schematic cross-sectional view of a state in which a photoconductor is placed in a mold. Schematic diagram of a typical image forming apparatus

Hereinafter, the best mode for carrying out the present invention will be described. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.
The image forming apparatus of the present invention operates so that the absolute value of the dark portion surface potential of the electrophotographic photosensitive member is 450 V or less. The cylindrical electrophotographic photosensitive member mounted on the image forming apparatus is packed with a protective sheet before mounting.

<Protective sheet>
The protective sheet 2 is used to protect and shield the photosensitive film of the drum 1, and has a size that can cover the entire outer peripheral surface of the drum 1, but partially protrudes from the upper and lower ends of the drum. There is also. The protective sheet 2 is desirably provided with smoothness in order to prevent the occurrence of scratches on the drum surface, and light shielding properties in order to suppress deterioration due to sunlight or fluorescent lamps. Examples of the material used for the protective sheet 2 include carbon-doped paper and polyethylene, or paper laminated with a carbon layer. From the viewpoint of cost and ease of handling, carbon-doped paper is preferable, In particular, for the purpose of reducing the surface resistance, paper doped with a large amount of carbon is preferable.

In the present invention, the effect is achieved by controlling the surface resistance of the protective sheet. The surface resistance of the protective sheet is 10 ¹¹ Ω / cm ² or less, preferably 1 from the viewpoint of imparting conductivity.
0 ⁵ Ω / cm ² or less, and 10 ² Ω / cm ² or more, preferably 10 ³ Ω / cm ² or more, from the viewpoint of ease of papermaking and cost. The surface resistance can be measured using Hiresta or Loresta manufactured by Mitsubishi Chemical Analytech. Control of the surface resistance of the protective sheet is often determined by the particles kneaded in the sheet, and in particular, it can be controlled by changing the amount of carbon black kneaded. Carbon black is added by kneading into pulp, but most of it is discharged by the papermaking process, and it is difficult to control the content in the end. On the other hand, after determining a certain condition, a method is generally used in which the conductivity of the black paper is managed to keep the mixing ratio of carbon black invisible.

  The surface roughness of the protective sheet is 5.00 μm or less, preferably 4.00 μm or less, and more preferably 2.00 μm or less from the viewpoint of preventing surface scratches if the maximum height is Ry. From the viewpoint of preventing slippage, the thickness is 0.10 μm or more, preferably 0.50 μm or more, and more preferably 1.00 μm or more. The higher the maximum height, the more surface flaws and deposits derived from the protective sheet. If it is arithmetic surface roughness Ra, it is 0.5 micrometer or less from a viewpoint of surface flaw prevention, Preferably it is 0.40 micrometer or less, More preferably, it is 0.30 micrometer or less. From the viewpoint of preventing slipping, the thickness is 0.01 μm or more, preferably 0.10 μm or more, and more preferably 0.20 μm or more.

  Specifically, as shown in FIG. 2, the size of the protective sheet is such that the width W of the protective sheet 2 corresponding to the circumferential direction of the drum 1 is generally 10 mm added to the circumferential length of the drum 1. The above is less than the length obtained by subtracting 4 mm from the length of 1.5 times the circumferential length of the drum 1. In particular, if the protective sheet is in the roughness range specified in the present application, friction occurs in the joined portions, so there is no need to set the width W long enough to prevent displacement, and protection per use. The amount of sheets can be reduced. When the width W of the protective sheet 2 is too short, a portion that is not covered with the protective sheet 2 is generated on the outer peripheral surface of the drum 1, and there is a possibility that the photosensitive film of the drum 1 is exposed and / or scratched. If the width W of the protective sheet 2 is too long, when the drum 1 is placed in a mold 9 having a semicircular depression described later (see FIG. 3), the winding end 21 of the protective sheet 2 hits the mold 9 and the drum 1 May rise.

<Cylindrical electrophotographic photoreceptor>
The cylindrical electrophotographic photosensitive member is mounted on an image forming apparatus in which the absolute value of the dark portion surface potential is 450 V or less. Preferably, the absolute value of the dark portion surface potential is 100 V or more, more preferably 200 V.
That's it.
Although there is no restriction | limiting in particular about the cylindrical electrophotographic photoreceptor of this invention, What coated the photosensitive layer by the well-known method on a cylindrical conductive support body is generally used.

In the present invention, the photosensitive layer is provided on a conductive support. As the conductive support, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, polyester film on which aluminum is vapor-deposited, paper, and glass are mainly used.
A publicly known barrier layer as commonly used may be provided between the conductive support and the photosensitive layer. Examples of the barrier layer include inorganic layers such as aluminum anodized film, aluminum oxide and aluminum hydroxide, organic layers such as polyvinyl alcohol, casein, polyvinyl pyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and polyamide. Is used. Further, these barrier layers may contain conductive or semiconductive fine particles such as metals such as aluminum, copper, tin, zinc and titanium, or oxides of these metals.

The photosensitive layer of the present invention is preferably a laminated type basically composed of a charge generation layer and a charge transport layer, but may be a so-called monolayer dispersion type consisting of a single photosensitive layer.
Hereinafter, the laminated type will be mainly described.

<Charge generating material>
The charge generating material may be used alone or in a mixed state with several dyes and pigments. Examples of the charge generation material include selenium and its alloys, amorphous silicon and other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, benzimidazole pigments, Various photoconductive materials such as organic pigments such as squalium pigments can be used, and it is particularly desirable to use organic pigments, especially phthalocyanine pigments and azo pigments. When using phthalocyanine pigments, specifically, metal-free phthalocyanines, metals such as copper, indium, gallium, tin, titanium, zinc, vanadium, or oxides and chloride coordinated phthalocyanines are used. . In particular, oxytitanium phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine such as x-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), D-type (also known as Y-type), etc. Is preferred. Of the crystalline forms of oxytitanium phthalocyanine mentioned here, the A type and B type are shown as I phase and II phase by W. Hiller et al. (Z. Kristallogr., 159 (1982) 173). A type is known as a stable type. D type is powder X using CuKα ray
In the line diffraction, the crystal form is characterized in that the diffraction angle 2θ ± 0.2 ° shows a clear peak at 27.3 °.

Examples of preferable azo pigments include azo pigments described in JP-A-63-259572 and JP-A-5-32905, and the azo compounds shown in JP-A-9-281733 are particularly preferable.
These phthalocyanine compounds and azo pigments may be used alone, or may be used as a mixture of a plurality of phthalocyanine compounds, a mixed crystal, a mixture of a plurality of azo pigments, or a mixture of a phthalocyanine compound and an azo pigment.

  The charge generation layer may be formed by using the above pigments, for example, polyester resin, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polyester, polycarbonate, polyarylate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin. , Cellulose ester, cellulose ether, polyvinyl chloride copolymer, polyvinyl acetate copolymer and the like may be used in a dispersion layer in a form bound with various binder resins.

  The ratio (weight ratio) of the binder resin to these compounds is used in the range of 0.2 to 5 with respect to these compounds 1. The film thickness is usually 0.1 to 2 μm, preferably 0.1 to 0.8 μm. In addition, the charge generation layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving coating properties, as necessary.

<Charge transport layer>
The charge transport layer of the multilayer photoreceptor contains a charge transport material, a binder resin, and other components used as necessary. Specifically, such a charge transport layer is prepared by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent to prepare a coating solution. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating on an undercoat layer and drying. The charge transport layer is preferably the outermost layer.

  As the charge transporting material, other known charge transporting materials can be used, and the kind thereof is not particularly limited. For example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, enamine derivatives, butadiene derivatives, and derivatives thereof may be used. What was combined two or more is preferable. Specific examples of suitable structures of the charge transport material are shown below. These specific examples are shown for illustration, and any known charge transporting material may be used as long as it does not contradict the gist of the present invention.

<Charge transport layer>
When forming the charge transport layer of the function-separated type photoreceptor having the charge generation layer and the charge transport layer, a binder resin is used to ensure film strength.
In the case of the charge transport layer of the functional separation type photoconductor, a coating solution obtained by dissolving or dispersing the charge transport material and various binder resins in a solvent, or in the case of a single layer type photoconductor, the charge generation material and the charge transport It can be obtained by applying and drying a coating solution obtained by dissolving or dispersing the substance and various binder resins in a solvent.

<Binder resin>
Examples of the binder resin include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester carbonate, polysulfone, polyimide, phenoxy, epoxy, silicone resin, and the like. These partially crosslinked cured products can also be used. Of the binder resins, polycarbonate resins and polyester resins are particularly preferable. These resins may be used alone or in combination.

  First, the polyester resin will be described. Generally, a polyester resin is obtained by polycondensing a polyhydric alcohol component and a polyvalent carboxylic acid component such as a carboxylic acid, a carboxylic acid anhydride, or a carboxylic acid ester as a raw material monomer. When the outermost surface layer of the photoreceptor contains a polyester resin, static electricity is likely to be generated because the dielectric constant of the photosensitive layer is higher than that of polycarbonate, and memory is generated by adjusting the surface resistivity of the protective sheet. Can be prevented.

As the polyhydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (
4-Hydroxyphenyl) propane and other bisphenol A alkylene (2 to 3 carbon atoms) oxide (average added mole number 1 to 10) adduct, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane , Hydrogenated bisphenol A, sorbitol, or alkylene thereof (2 carbon atoms)
-3) Oxide (average added mole number 1 to 10) adduct, aromatic bisphenol and the like, and those containing one or more of these are preferable.

  Moreover, as polyvalent carboxylic acid component, carbon number 1-20, such as dicarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, biphenyl dicarboxylic acid, and diphenyl ether dicarboxylic acid, dodecenyl succinic acid, octyl succinic acid Succinic acid, trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl (carbon number of 1 to 3) esters of those acids substituted with an alkyl group of the above or an alkenyl group having 2 to 20 carbon atoms. And those containing one or more of these are preferred.

  Among these polyester resins, preferred are wholly aromatic polyarylate resins having a structural unit represented by the following formula (A).

(In Formula (A), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, X represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group. U represents 0. And represents an integer of 2 or less, and Y represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group.
In the above formula (A), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent. As carbon number which an arylene group has, it is 6 or more normally, Preferably it is 7 or more, and the upper limit is 20 or less normally, Preferably it is 10 or less, More preferably, it is 8 or less. If the number of carbon atoms is too large, the production cost increases and the electrical characteristics may deteriorate.

Specific examples of Ar ^{1 to} Ar ⁴ include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, naphthylene group, anthrylene group, phenanthrylene group, and the like. Among these, the arylene group is preferably a 1,4-phenylene group from the viewpoint of electrical characteristics. An arylene group may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

Specific examples of the substituents for Ar ^{1 to} Ar ⁴ include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Among them, considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group is preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group, and is preferably an aryl group. Is preferably a phenyl group or a naphthyl group, a halogen group is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and an alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group or a butoxy group. In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.

More specifically, Ar ³ and Ar ⁴ each independently preferably has a substituent number of 0 or more and 2 or less, more preferably has a substituent from the viewpoint of adhesion, and among these, substitution from the viewpoint of wear resistance. It is particularly preferable that the number of groups is one. Moreover, as a substituent, an alkyl group is preferable and a methyl group is particularly preferable.
On the other hand, Ar ¹ and Ar ² each independently preferably have 0 or more and 2 or less substituents, and more preferably have no substituents from the viewpoint of wear resistance.

In the above formula (A), Y is a single bond, an oxygen atom, a sulfur atom, or an alkylene group. As the alkylene group, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, — are more preferable. C (CH ₃ ) ₂ — and cyclohexylene are preferable, and —CH ₂ — and —CH (CH ₃ ) — are particularly preferable.

In the above formula (A), X is a single bond, an oxygen atom, a sulfur atom, or an alkylene group, and among them, X is preferably an oxygen atom. In that case, v is preferably 0 or 1, and is particularly preferably 1.
Specific examples of the preferred dicarboxylic acid residue when u is 1 include diphenyl ether-2
, 2'-dicarboxylic acid residue, diphenyl ether-2,3'-dicarboxylic acid residue, diphenyl ether-2,4'-dicarboxylic acid residue, diphenyl ether-3,3'-dicarboxylic acid residue, diphenyl ether-3,4 Examples include a '-dicarboxylic acid residue, diphenyl ether-4,4'-dicarboxylic acid residue, and the like. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

Specific examples of the dicarboxylic acid residue when u is 0 include phthalic acid residue, isophthalic acid residue, terephthalic acid residue, toluene-2,5-dicarboxylic acid residue, p-xylene-2,5- Dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, Biphenyl-4,4′-dicarboxylic acid residue may be mentioned, preferably phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6- Dicarboxylic acid residues, biphenyl-2,2′-dicarboxylic acid residues, biphenyl-4,4′-dicarboxylic acid residues, particularly preferably isophthalic acid residues and terephthalic acid residues. It is also possible to combine a plurality of carbon residues.

  Specific examples of suitable structures of the binder resin are shown below. These specific examples are shown for illustration, and any known binder resin may be used as long as it does not contradict the gist of the present invention.

  Next, the polycarbonate resin will be described. Generally, polycarbonate resin is produced by a solvent method such as an interfacial method (interfacial polycondensation method) or a solution method in which bisphenols and phosgene are reacted in a solution, or a transesterification reaction between bisphenol and a carbonic acid diester. A melting method in which a polycondensation reaction is carried out by using a method is widely used as an inexpensive production method. As the bisphenols, the following compounds are preferably used. As the polycarbonate resin, not only a homopolymer composed of one kind of bisphenols but also a copolymer produced by copolymerizing two or more kinds of bisphenols can be used.

  Specific examples of suitable structures of the binder resin are shown below. These specific examples are shown for illustration, and any known binder resin may be used as long as it does not contradict the gist of the present invention.

  The viscosity average molecular weight of the binder resin used in the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but is preferably 10,000 or more, more preferably 20,000 or more, and the upper limit is preferably It is desirable that it is 150,000 or less, more preferably 120,000 or less, and still more preferably 100,000 or less. If the value of the viscosity average molecular weight is too small, the mechanical strength of the photoreceptor may be insufficient.If it is too large, the viscosity of the coating solution for forming the photosensitive layer may be too high and the productivity may decrease. is there.

  The ratio of the binder resin to the charge transport material is preferably 30 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 35 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 40 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 100 parts by mass or less. Among these, from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by mass or less is preferable, from the viewpoint of printing durability, 80 parts by mass or less is more preferable, and from the viewpoint of scratch resistance, 60 parts by mass or less is particularly preferable.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, on the other hand, usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. Is in the range of 30 μm or less.
<Image forming apparatus>
Next, the image forming apparatus used in the present invention will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 4, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, a developing device 4, and a transfer device 5, and further, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is an electrophotographic photoreceptor according to the present invention described above. In FIG. 4, as an example, the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. A drum-shaped photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are disposed along the outer peripheral surface of the electrophotographic photosensitive member 1.

The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 4, a roller type charging device (charging roller) is shown as an example of the charging device 2, but a corona charging device such as a corotron or a scorotron, a contact type charging device such as a charging brush, etc. are often used.
In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge having both of them (hereinafter referred to as a photosensitive cartridge as appropriate). It is desirable to use in such a form. For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used. As will be described later, this image forming apparatus uses the toner of the present invention described above as the toner.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light having a wavelength of 780 nm, monochromatic light having a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light having a wavelength shorter than 380 nm to 600 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. In FIG. 2, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which the toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed by a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with a resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (general blade linear pressure is 0.05 to 5 N / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a transfer material (paper, medium) P. Is.

  The cleaning device 6 is not particularly limited, and any cleaning device such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, or a blade cleaner can be used, but a blade cleaner is preferable from the viewpoint of effectiveness. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 4 shows an example in which a heating device 73 is provided inside the upper fixing member 71. As the upper and lower fixing members 71 and 72, known heat fixing members such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll coated with a fluororesin, or a fixing sheet are used. be able to. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

  In the image forming apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −400 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage. In any case, in the present invention, charging is performed so that the absolute value is 450 V or less.

Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.
The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.

When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.
After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

Since the image forming apparatus of the present embodiment uses the photoconductor of the present invention, it can be miniaturized and can realize high image quality of formed images without causing defective cleaning. It is.
In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  Further, the image forming apparatus may be further modified. For example, the image forming apparatus may be configured such that an auxiliary charging process or the like can be performed, offset printing may be performed, or a plurality of types of toner may be used. It is good also as a structure of a full color tandem system.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Manufacture of photoconductor>
A slurry obtained by mixing a rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane with respect to the titanium oxide in a ball mill is dried, and further methanol is added. Hydrophobic treated titanium oxide obtained by washing and drying with a Ultra Aspec mill in a mixed solvent of methanol / 1-propanol to form a hydrophobized titanium oxide dispersion slurry, and the dispersion slurry And a mixed solvent of methanol / 1-propanol / toluene (weight ratio 7/1/2), and ε-caprolactam / bis (4-amino-3-methylcyclohexyl) methane / hexamethylenediamine / decamethylenedicarboxylic acid / From octadecamethylene dicarboxylic acid (composition mol% 75 / 9.5 / 3 / 9.5 / 3) After stirring and mixing with the copolymerized polyamide pellets, the polyamide pellets are dissolved, and then subjected to ultrasonic dispersion treatment to contain hydrophobically treated titanium oxide / copolymerized polyamide in a weight ratio of 3/1. A dispersion having a solid content concentration of 18.0% was obtained.

This dispersion was dip-coated on an aluminum cylinder having an outer diameter of 24 mm, a length of 255 mm, and a thickness of 0.75 mm, and an undercoat layer was provided so that the film thickness after drying was 1.5 μm.
Next, as a charge generation material, 10 parts by weight of oxytitanium phthalocyanine showing a strong diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° in X-ray diffraction by CuKα rays is 150 weights of 1,2-dimethoxyethane. In addition to the part, a pulverization dispersion process was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by weight of the pigment dispersion thus obtained was added to 100 parts by weight of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name # 6000C), and 1,2-dimethoxyethane was added. And finally a dispersion having a solid content concentration of 4.0% was prepared.

This dispersion was dip-coated on the above undercoat layer so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.
Next, as a charge transport material, 75 parts by weight of a charge transport material composed of an isomer mainly having the following structure shown in JP-A-2002-80432,

40 parts by weight of a polycarbonate resin (viscosity average molecular weight: 50,000) having the following structure as a repeating unit as a binder:

60 parts by weight of a polyarylate resin (viscosity average molecular weight: 40,000) having the following structure as a repeating unit as another type of binder,

2 parts of 3,5-di-t-butyl-4-hydroxytoluene as an antioxidant and 0.05 parts by weight of silicone oil as a leveling agent were mixed with tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene). ) A solution dissolved in 640 parts by weight was dip-coated on the above-described charge generation layer so that the film thickness after drying was 25 μm to obtain a photosensitive drum.

<Wound of protective sheet>
Each of the protective sheets shown in Table 1 is cut into a size of 252 mm × 100 mm, arranged so that the longitudinal direction of the photosensitive drum (255 mm) and the longitudinal direction of the protective sheet (252 mm) coincide with each other, the protective sheet is wound, and the adhesive tape Fastened with.

<Print test>
Hold the photoconductor drum wrapped with a protective sheet horizontally from the inside, grab the cylindrical protective sheet from the outer surface, rotate it around, and then hold the adhesive sheet with the adhesive tape for 0.5 sec. Stripped in the circumferential direction at a speed of.
In order to confirm the state of static electricity generated on the surface of the photoconductive drum, a CLP-680ND (manufactured by Samsung Electronics), a commercially available printer in the United States, can be modified to change the voltage applied to the charging roller to the black drum. After doing so, it was mounted on a black drum cartridge, and a printing test was performed by changing the surface potential of the photosensitive member dark part, and it was confirmed whether or not the influence of the electrostatic memory could be seen on the image. Further, in order to investigate the wear resistance amount, a printing test of 6,000 sheets was performed, and the reduction amount of the film thickness of the photosensitive layer was measured. The results are shown in Table-2.

  From the above results, it can be seen that it is effective to suppress the dark portion surface potential in order to suppress the wear resistance. On the other hand, when the dark portion surface potential is large as in Reference Example 1 to Reference Example 12, Since the electrostatic memory on the surface of the photoreceptor generated when the sheet is peeled off does not appear as an image, it is not necessary to select a protective sheet. The inventor has found that selection of the surface resistance of the protective sheet is important only when the dark portion surface potential is small, and has completed the present invention.

Claims (1)

A packing method for packing the photosensitive member charged with a protective sheet so that the absolute value of the dark portion surface potential of the cylindrical electrophotographic photosensitive member is 450 V or less,
Characterized by using the protective sheet the surface resistance of 10 ⁵ Ω / cm ² or less at 10 ³ Ω / cm ² or more, packing how of the cylindrical electrophotographic photosensitive member.

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