JP2011085621A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus using an electrophotographic photoreceptor that prevents scratches (flows) or density spots (unevenness) on the photoreceptor surface even in long-term use in a charging process using a contact charging device, and that has excellent wear resistance and gas resistance. <P>SOLUTION: The image forming apparatus includes: a contact charging device that comes into contact with the surface of an electrophotographic photoreceptor having a photosensitive layer and a surface layer successively layered on a conductive support, to charge the surface of the photoreceptor; an image exposing means forming an electrostatic latent image on the electrophotographic photoreceptor; a developing means developing the electrostatic latent image formed on the electrophotographic photoreceptor; and a transfer means transferring the toner image developed on the photoreceptor. The surface layer of the electrophotographic photoreceptor contains a product obtained by reacting a metal oxide surface-treated with a compound having at least a reactive organic group, with a curable compound for forming a chemical bond with the reactive organic group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus. More specifically, the electrophotographic photosensitive member is excellent in wear resistance and gas resistance, and has no scratches or density spots (unevenness) on the surface of the photosensitive member even in long-term use in a charging process using a contact charger. The present invention relates to an image forming apparatus using.

  Conventionally, a non-contact corona discharge device is generally used as a charging device for a photoreceptor used in an electrophotographic apparatus such as a plain paper copier, a laser printer, and an LED printer, and has been widely used so far. However, since the corona discharge device is an air discharge, the generation of ozone and NOx is inevitable.

  In the corona charging method, generally, a wire and a shield case are arranged around it, and a high voltage is applied between them. However, when used for a long time, the product due to discharge is deposited on the wire and the case. Discharge becomes unstable. In particular, during negative corona discharge, there is a problem that this product becomes a fouling of the wire and makes the discharge remarkably unstable, and further increases the generation of ozone and NOx.

  Under these circumstances, in recent years, in order to avoid the generation of ozone and NOx, which are undesirable for the human body due to environmental problems, the development of contact charging systems using charging rollers and magnetic brushes that generate less ozone with a low-voltage power supply has been promoted. (For example, Patent Document 1).

  However, in this contact charging method, a charging member such as an elastic body or a magnetic brush may be placed in a stationary state in a state where the charging member is in contact with an electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”). Yes (for example, when image formation is temporarily stopped), and when image formation is resumed thereafter, there is a problem that unevenness of image occurs at the contact portion between the charging member and the photosensitive member. As a solution to such a problem, it has been proposed that the hardness of the surface coating of the electrophotographic photosensitive member is not less than a specific hardness (for example, Patent Document 2).

  However, in recent years, image forming means using an electrophotographic process has been required to have durability higher than that of the past, such as development to a production print area. Therefore, not only a physical load but also a resistance against a chemical load (discharge deterioration: addition of NOx and oxidation) is required.

  In general, the charge transport layer in the photosensitive layer of an electrophotographic photoreceptor has many compounds that are easily deteriorated, such as a charge transport material, and has low durability against chemical loads. Therefore, a technique for improving the resistance against physical and chemical loads by using a functionally separated surface layer has been proposed.

  For example, a surface layer formed of a polymerizable monomer (monomer) in an electrophotographic photoreceptor is used for improving mechanical strength and maintaining appropriate elasticity. And in order to improve mechanical strength further and to maintain electroconductivity, it is performed to make a surface layer contain electroconductive particle, especially metal oxide particle (filler).

  As described above, the surface layer of the electrophotographic photoreceptor contains metal oxide particles, and metal oxide is formed to fill the voids in the three-dimensional structure formed from a polymerizable monomer and polymerized by light or heat. It is already known to add physical particles (for example, see Patent Document 3).

  However, it is difficult to control the dispersion state of the filler. When the polymerizable monomer is polymerized or when the solvent is dried, the filler aggregates, and the filler is cured in a non-uniformly dispersed state. Due to the curing in the non-uniform aggregation state, the transparency is not sufficient and uniform chargeability cannot be obtained, and at the same time, a good image cannot be obtained due to poor cleaning.

  As a countermeasure against these problems, it is possible to obtain a surface layer in which metal oxide particles are uniformly dispersed by imparting a reactive group to the surface of metal oxide particles and curing in the most dispersible state immediately after coating. Has been made. However, in the system in which the metal oxide particles are contained in the surface layer, when the solvent evaporates, the charge balance in the system is temporarily lost, the metal oxide particles are aggregated, and the polymerizable monomer is cured. In doing so, the tendency of the metal oxide particles existing in a free state to harden with a non-uniform distribution is remarkable (see, for example, Patent Document 4).

  As a preventive measure, the surface layer of the electrophotographic photosensitive member is formed by polymerization of a curable acrylic monomer or oligomer having a reactive acrylic group or methacrylic group, and the conductive powder has a reactive acrylic group or An invention having a configuration in which a surface treatment is performed with a coupling agent having a methacryl group is disclosed (see Patent Document 5).

  However, the various known techniques described above are not sufficient in terms of resistance to physical load and chemical deterioration, and development of a technique for realizing further improvement (improvement) is desired.

JP 2001-235880 A JP 2005-31342 A JP 2000-267324 A JP-A-6-35220 Japanese Patent Laid-Open No. 11-95474

  The present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is that scratches and scratches on the surface of the photosensitive member and unevenness in density (unevenness) occur even in long-term use in a charging process using a contact charger. It is another object of the present invention to provide an image forming apparatus using an electrophotographic photoreceptor excellent in wear resistance and gas resistance.

  The above-mentioned problem according to the present invention is solved by the following means.

  1. Contact charging means for charging the surface of the electrophotographic photosensitive member by contacting the surface of the electrophotographic photosensitive member having a photosensitive layer and a surface layer on a conductive support; and an electrostatic latent image on the electrophotographic photosensitive member. An image provided with an image exposure means to be formed, a developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and a transfer means for transferring a toner image developed on the electrophotographic photosensitive member A forming apparatus, wherein the surface layer of the electrophotographic photosensitive member is surface-treated with a compound having at least a reactive organic group, and a curable compound capable of forming a chemical bond with the reactive organic group, An image forming apparatus characterized by containing a product obtained by reacting.

  2. 2. The image forming apparatus according to 1 above, wherein the compound having a reactive organic group is a silane compound having a reactive acryloyl group or a methacryloyl group.

  3. 3. The image forming apparatus as described in 1 or 2 above, wherein the curable compound is an acrylic monomer or oligomer having an acryloyl group or a methacryloyl group.

4). 4. The image forming apparatus as described in 3 above, wherein the ratio Ac / M of the molecular weight M of the acrylic monomer or oligomer having an acryloyl group or methacryloyl group and the number Ac of the acryloyl group or methacryloyl group is as follows.
0.005 <Ac / M <0.012

  By the above means of the present invention, an electron having no abrasion (scratch) or density unevenness (unevenness) on the surface of the photoreceptor and excellent wear resistance and gas resistance even in a long-term use in a charging process using a contact charger. An image forming apparatus using a photographic photoreceptor can be provided.

  That is, the surface layer according to the present invention is remarkably excellent in physical strength and chemical deterioration resistance for the following reasons.

(1) Abrasion resistance / scratch resistance (surface scratches) Since the outermost surface of the electrophotographic photosensitive member according to the present invention does not contain a plastic and easily deteriorated compound such as a charge transport material, it is physically and chemically Excellent durability against both loads.

  Further, even in a contact charging system in which a physical load is increased as compared with the corotron method, the photoconductor configured according to the present invention has sufficient durability.

  In contact charging, it is important to be stronger against chemical degradation than the scorotron method. This is because the chemically deteriorated portion is an aggregate of small molecules due to the addition or oxidation of NOx, and volatilizes due to the friction with the charger.

  Therefore, it is essential to have excellent durability against chemical loads, and the photoconductor having the structure according to the present invention has a surface layer structure that is resistant to chemical loads and has excellent durability.

(2) Concentration unevenness (unevenness) The electrophotographic photosensitive member according to the present invention is excellent in abrasion resistance, and therefore can be printed in a state where the surface roughness is maintained, and in a state where dirt such as toner and dust is involved. It is never imaged.

  That is, not only the photoconductor but also the charger is prevented from being contaminated, charging spots (unevenness) and unstable discharge are suppressed, and stable image formation without density spots (unevenness) is possible over a long period of time.

1 is a diagram illustrating an example of an image forming apparatus that performs roller charging. Contact-type magnetic brush charging device diagram The figure which shows the relationship between the alternating current bias voltage and charging potential by the charging device of FIG. Sectional drawing which shows an example of the image forming apparatus which has the magnetic brush charger of this invention

  The image forming apparatus of the present invention comprises a contact charger for contacting the surface of an electrophotographic photosensitive member formed by sequentially laminating a photosensitive layer and a surface layer on a conductive support to charge the surface of the electrophotographic photosensitive member, Image exposing means for forming an electrostatic latent image on the electrophotographic photosensitive member, developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and developed on the electrophotographic photosensitive member An image forming apparatus provided with a transfer means for transferring a toner image, wherein the surface layer of the electrophotographic photosensitive member forms at least a metal oxide having a reactive organic group and a chemical bond with the reactive organic group It contains a product obtained by reacting with a possible curable compound. This feature is a technical feature common to the inventions according to claims 1 to 4.

As an embodiment of the present invention, it is preferable that the compound having a reactive organic group is a silane compound having a reactive acryloyl group or a methacryloyl group from the viewpoint of manifesting the effects of the present invention. The curable compound is preferably an acrylic monomer or oligomer having an acryloyl group or a methacryloyl group. Furthermore, in this case, the ratio Ac / M of the molecular weight M of the acrylic monomer or oligomer having the acryloyl group or methacryloyl group and the number Ac of the acryloyl group or methacryloyl group:
0.005 <Ac / M <0.012
It is preferable that the relationship is

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.

(Outline of the configuration of the electrophotographic photoreceptor)
The electrophotographic photosensitive member according to the present invention is basically an electrophotographic photosensitive member in which a photosensitive layer and a surface layer are sequentially laminated on a conductive support, and the surface layer has at least a reactive organic group. And a product obtained by reacting a metal oxide particle surface-treated with a compound having a curable compound capable of forming a chemical bond with the reactive organic group.

  Hereinafter, the constituent elements of the electrophotographic photosensitive member according to the present invention will be described in detail.

(Surface layer)
As described above, the surface layer according to the present invention reacts a metal oxide surface-treated with a compound having at least a reactive organic group and a curable compound capable of forming a chemical bond with the reactive organic group. It contains the product obtained. Hereinafter, each compound will be described in detail.

[Metal oxide particles]
The metal oxide particles used in the present invention may be metal oxide particles including transition metals, for example, silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, aluminum oxide, tantalum oxide, indium oxide. Examples include metal oxide particles such as bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide, titanium oxide, niobium oxide, molybdenum oxide, and vanadium oxide. Of these, particles of tin oxide, alumina, zinc oxide, titanium oxide and the like are preferable, and tin oxide and alumina are particularly preferable.

  As the metal oxide particles, those produced by a general production method such as a gas phase method, a chlorine method, a sulfuric acid method, a plasma method, or an electrolytic method are used.

  The number average primary particle size of the metal oxide is preferably in the range of 1 to 300 nm. Especially preferably, it is 3-100 nm. When the particle size is small, the wear resistance is not sufficient, and when the particle size is large, writing light may be scattered, or the particles may inhibit photocuring and the wear resistance may be insufficient.

  The number average primary particle size of the metal oxide particles is a photographic image (excluding aggregated particles) taken with a scanning electron microscope (manufactured by JEOL Ltd.) with a magnification of 10000 times, and 300 particles randomly taken by a scanner. A) automatic image processing analyzer LUZEX AP (Nireco Corp.) software version Ver. The number average primary particle size was calculated using 1.32.

  The ratio of the metal oxide particles in the surface layer is 1 to 200 parts by mass, particularly preferably 30 to 120 parts by mass with respect to 100 parts by mass of the curable compound.

[Compound having a reactive organic group]
The compound having a reactive organic group used for the surface treatment of the metal oxide particles will be described.

  As the compound having a reactive organic group used in the present invention, the functional group having a carbon-carbon double bond and the polar group such as an alkoxy group coupled with the hydroxyl group (hydroxyl group) on the surface of the metal oxide particle are the same. A compound contained in the molecule is preferred. The compound having a functional group having a carbon-carbon double bond is preferably a compound having a functional group that is polymerized (cured) by irradiation with active rays such as ultraviolet rays or electron beams to become a resin such as polystyrene or polyacrylate. Among them, a silane compound having a reactive acryloyl group or a methacryloyl group is particularly preferable because it can be cured in a small amount of light or in a short time.

  The metal oxide particles surface-treated with the compound having a reactive organic group used in the present invention can be produced, for example, by reacting a compound represented by the following general formula (1) with the metal oxide particles. it can.

  That is, the following general formula (1);

(Wherein R ³ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aralkyl group having 1 to 10 carbon atoms, R ⁴ is an organic group having a polymerizable double bond, X is a halogen atom, an alkoxy group, an acyloxy group) Group, aminoxy group, phenoxy group, and n is an integer of 1 to 3) and metal oxide particles having a hydroxyl group (hydroxyl group) on the surface (generally, no surface treatment is performed). The metal oxide particles can be produced by reacting the surface with a hydroxyl group (hydroxyl group).

  Further, the silane compound to be reacted with the metal oxide particles is not particularly limited as long as it is a compound having a silyl group, particularly a hydrolyzable silyl group and capable of radical polymerization.

  Examples of the compound represented by the general formula (1) will be given below.

_{S-1 CH 2 = CHSi (} CH 3) (OCH 3) 2
_{S-2 CH 2 = CHSi (} OCH 3) 3
S-3 CH ₂ = CHSiCl _{3
S-4 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5 CH 2 = CHCOO (} CH 2) 2 Si (OCH 3) 3
_{S-6 CH 2 = CHCOO (} CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7 CH 2 = CHCOO (} CH 2) 3 Si (OCH 3) 3
_{S-8 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) Cl 2
_{S-9 CH 2 = CHCOO (} CH 2) 2 SiCl 3
_{S-10 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) Cl 2
S-11 CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13 CH 2 = C (} CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17 CH 2 = C (} CH 3) COO (CH 2) 2 SiCl 3
_{S-18 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19 CH 2 = C (} CH 3) COO (CH 2) 3 SiCl 3
_{S-20 CH 2 = CHSi (} C 2 H 5) (OCH 3) 2
S-21 CH ₂ ═C (CH ₃ ) Si (OCH ₃ ) _{3
S-22 CH 2 = C (} CH 3) Si (OC 2 H 5) 3
_{S-23 CH 2 = CHSi (} OCH 3) 3
_{S-24 CH 2 = C (} CH 3) Si (CH 3) (OCH 3) 2
_{S-25 CH 2 = CHSi (} CH 3) Cl 2
_{S-26 CH 2 = CHCOOSi (} OCH 3) 3
_{S-27 CH 2 = CHCOOSi (} OC 2 H 5) 3
_{S-28 CH 2 = C (} CH 3) COOSi (OCH 3) 3
_{S-29 CH 2 = C (} CH 3) COOSi (OC 2 H 5) 3
_{S-30 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35 CH 2 = CHCOO (} CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36 CH 2 = CHCOO (} CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2
Moreover, you may use the silane compound which has the following reactive organic group other than the compound of the said General formula (1).

  These silane compounds can be used alone or in admixture of two or more.

[Production method of reactive metal oxide particles]
Next, the manufacturing method of the metal oxide particle (reactive metal oxide particle) surface-treated with the compound having a reactive organic group according to the present invention is a silane compound represented by the general formula (1) or the like. A case will be described as an example.

  When the surface treatment is performed, the treatment is performed using a wet media dispersion type apparatus using 0.1 to 200 parts by mass of a silane compound as a surface treatment agent and 50 to 5000 parts by mass of a solvent with respect to 100 parts by mass of the metal oxide particles. It is preferable to do.

  The surface treatment amount of the compound having a reactive organic group (the coating amount of the compound having a reactive organic group) is preferably 0.1% by mass or more and 60% by mass or more with respect to the metal oxide particles. Especially preferably, it is 5 mass% or more and 40 mass% or less.

  The surface treatment amount of the compound having a reactive organic group was determined by heat treating the metal oxide particles after the surface treatment at 550 ° C. for 3 hours, quantitatively analyzing the ignition residue with fluorescent X-rays, and calculating the molecular weight from the Si amount. It is obtained by conversion.

  The following describes a surface treatment method for producing metal oxide particles that are uniform and more finely surface-treated with a silane compound.

  That is, by subjecting a slurry (suspension of solid particles) containing metal oxide particles and a silane compound to wet pulverization, the metal oxide particles are refined and surface treatment of the metal oxide particles proceeds at the same time. Thereafter, since the solvent is removed to form powder, metal oxide particles that are surface-treated with a uniform and finer silane compound can be obtained.

  The wet media dispersion type apparatus, which is a surface treatment apparatus used in the present invention, is a metal oxide particle by filling beads in a container as a medium and rotating a stirring disk mounted perpendicularly to a rotation axis at high speed. It is a device having a step of crushing and pulverizing and dispersing the aggregated particles of the metal oxide, and the constitution thereof should be a type in which the metal oxide particles can be sufficiently dispersed and surface-treated when the surface treatment is performed on the metal oxide particles. For example, various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be adopted. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersive devices are pulverized and dispersed by impact crushing, friction, cutting, shear stress, etc., using a grinding medium such as balls and beads.

  As the beads used in the sand grinder mill, balls made of glass, alumina, zircon, zirconia, steel, flint stone and the like can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.3 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon, and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  By the wet treatment as described above, metal oxide particles surface-treated with the silane compound of the general formula (1) having a reactive organic group can be obtained.

  The titanium oxide particles have been described above, but metal oxide particles such as alumina, zinc oxide, and tin oxide also have hydroxyl groups (hydroxyl groups) on the surface in the same manner as titanium oxide. Metal oxide particles having a reactive organic group can be obtained by surface treatment with a silane compound such as formula (1). Here, having a reactive organic group means that a compound having a hydroxyl group (hydroxyl group) and a silyl group on the surface of the metal oxide particle forms a chemical bond by a hydrolysis reaction.

  Thereby, the reactive organic group in silane compounds, such as General formula (1), becomes the metal oxide particle which exists by coupling of the silane compound to the particle | grain surface.

  The metal oxide particles having a reactive organic group thus obtained can form a protective layer by the mutual reaction between these metal oxide particles, but more preferably, the metal oxide particles with the curable compound according to the present invention described below. It is preferable to form a protective layer by reaction.

  The metal oxide particles surface-treated with the compound having a reactive organic group form a surface layer by a reaction with the curable compound according to the present invention described below.

[Curable compound]
The curable compound according to the present application is not particularly limited as long as it is a compound that reacts with the reactive organic group of the metal oxide particles, but various compounds having a carbon-carbon double bond are particularly preferably used.

  The curable compound is preferably a radically polymerizable monomer that is polymerized (cured) by irradiation with actinic rays such as ultraviolet rays and electron beams, and becomes a resin generally used as a binder resin for a photoreceptor, such as polystyrene and polyacrylate. Of the radical polymerizable monomers, styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, and N-vinyl pyrrolidone monomers are particularly preferable. Among these, an acrylic monomer having an acryloyl group or a methacryloyl group is particularly preferable because it can be cured in a small amount of light or in a short time.

  In the present invention, these curable compounds according to the present invention may be used alone or in combination.

  Examples of the curable compound according to the present invention are shown below.

In the present invention, the acrylic monomer is a compound having an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—).

  Moreover, the number of Ac groups (the number of acryloyl groups) mentioned below represents the number of acryloyl groups or methacryloyl groups.

  However, in the above, R and R 'are respectively shown below.

  In the present invention, the acrylic monomer preferably has 2 or more functional groups, particularly preferably 4 or more. In the acrylic monomer, the ratio of the molecular weight M of the compound having an acryloyl group or methacryloyl group to the number Ac of the acryloyl group or methacryloyl group (Ac / M, number of acryloyl groups or methacryloyl groups / molecular weight) is greater than 0.005. Is preferred. When such a compound is used and Ac / M is increased by increasing the polymerization reaction rate, an electrophotographic photoreceptor having a high film density and excellent gas barrier properties can be obtained.

  Examples of compounds with Ac / M greater than 0.005 include No. 1 to 19, 21, 23, 26, 28, 30, 31 to 33, 35, 37, 40 to 44, and 61.

  Furthermore, it is particularly preferable that the acrylic monomer has a reactive methacryloyl group, and the Ac / M is in a range satisfying a condition that is greater than 0.005 and less than 0.012.

  By using in this relationship range, the crosslinking density is increased and the abrasion resistance of the photoreceptor is improved.

  In the present invention, two or more curable compounds having different functional group densities may be mixed and used.

[Additives other than the above, other]
The surface layer can form a cured film by applying and reacting a coating liquid containing a polymerization initiator, lubricant particles, an antioxidant, and the like, if necessary, in addition to the curable compound and metal oxide particles.

  When reacting metal oxide particles having a reactive organic group and a curable compound according to the present invention, a method of reacting by electron beam cleavage, a radical polymerization initiator or a cationic polymerization initiator is added, and light, A method of reacting with heat is used. As the polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. Further, both light and heat initiators can be used in combination.

As a radical polymerization initiator of these photocurable compounds, a photopolymerization initiator is preferable, and among them, an alkylphenone compound or a phosphine oxide compound is preferable. In particular, a compound having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is preferable. The compound that initiates cationic polymerization, e.g., diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 - , CF ₃ SO ₃ ^- ionic polymerization initiator or sulfonic acid sulfonated materials that generate a such as salts, halides or generates hydrogen halide, can be mentioned nonionic polymerization initiator such as iron arene complex. In particular, a sulfonate that generates a sulfonic acid that is a nonionic polymerization initiator and a halide that generates a hydrogen halide are preferable.

  The photoinitiator used preferably below is illustrated.

  Examples of α-aminoacetophenone series

  Examples of α-hydroxyacetophenone compounds

  Examples of acylphosphine oxide compounds

  Examples of other radical polymerization initiators

  In order to form a surface layer of a photocurable resin, it is mixed with metal oxide particles surface-treated with a compound having a reactive organic group, a curable compound capable of forming a chemical bond with the reactive organic group, and the like. After the surface layer coating solution was prepared and the surface layer coating solution (the above composition) was coated on the photosensitive layer, the surface was first dried to such an extent that the fluidity of the coating film disappeared, and then irradiated with ultraviolet rays. A method of curing the layer and performing secondary drying to make the amount of the volatile substance in the coating film a specified amount is preferable.

  As a device for irradiating ultraviolet rays, a known device used for curing an ultraviolet curable resin can be used.

The amount of ultraviolet rays (mJ / cm ² ) for curing the resin with ultraviolet rays is preferably controlled by the ultraviolet irradiation intensity and irradiation time.

  On the other hand, as the thermal polymerization initiator, ketone peroxide compounds, peroxyketal compounds, hydroperoxide compounds, dialkyl peroxide compounds, diacyl peroxide compounds, peroxydicarbonate compounds, peroxyester compounds Compounds and the like are used, and these thermal polymerization initiators are disclosed in company product catalogs.

  In the present invention, as in the case of the photopolymerization initiator, these thermal polymerization initiators form metal oxide particles surface-treated with a compound having a reactive organic group, and a chemical bond with the reactive organic group. A surface layer coating solution is prepared by mixing with a possible curable compound or the like, and the coating solution is applied onto the photosensitive layer and then dried by heating to form the surface layer according to the present invention. As the thermal polymerization initiator, the above-mentioned other radical polymerization initiators can be used.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.1-50 mass parts with respect to 100 mass parts of a curable compound, Preferably it is 0.5-30 mass parts.

  The surface layer according to the present invention may further contain various charge transport materials.

  Various lubricant particles can be added to the surface layer used in the present invention. For example, fluorine atom-containing resin particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable. The ratio of the lubricant particles in the surface layer is preferably 5 to 70 parts by mass, more preferably 10 to 60% by mass with respect to 100 parts by mass of the acrylic resin. The average particle size of the lubricant particles is preferably 0.01 μm to 1 μm. Particularly preferably, it is 0.05 μm to 0.5 μm. The molecular weight of the resin can be appropriately selected and is not particularly limited.

  Solvents for forming the surface layer include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, Examples include, but are not limited to, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine.

  As a coating method, known methods such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, and a slide hopper method can be used.

  However, the surface layer coating method involves immersing the entire photoconductor in the surface layer coating solution to increase diffusion of the surface layer forming material to the lower layer, so that the photosensitive layer film below the surface layer is dissolved as much as possible. Therefore, it is preferable to use a coating method such as a circular amount regulation type (a circular slide hopper type is a typical example). The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

(Conductive support)
The support used in the present invention may be any one as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, aluminum or copper Metal foils such as those laminated on plastic films, aluminum, indium oxide and zinc oxide deposited on plastic films, metals with conductive layers applied alone or with a binder resin, plastic films and For example, paper.

(Middle layer)
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive layer and the photosensitive layer.

  The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Of these, an alcohol-soluble polyamide resin is preferred.

  As the solvent used for the intermediate layer, a solvent in which inorganic particles are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are excellent in solubility and coating performance of the polyamide resin. In addition, examples of co-solvents that can be used in combination with the above-described solvent to improve the storability and particle dispersibility and obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The density | concentration of binder resin is suitably selected according to the film thickness and production rate of an intermediate | middle layer.

  When the inorganic particles are dispersed, the mixing ratio of the inorganic particles to the binder resin at the time is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  As a means for dispersing the inorganic particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The method for drying the intermediate layer can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The thickness of the intermediate layer is preferably from 0.1 to 15 μm, more preferably from 0.3 to 10 μm.

(Photosensitive layer)
In the present invention, the configuration of the photosensitive layer is not particularly limited, but a so-called laminated photosensitive layer having a charge generation layer and a charge transport layer is preferable.

(Charge generation layer)
The charge generation layer used in the present invention preferably contains a charge generation material and a binder resin, and is formed by dispersing and coating the charge generation material in a binder resin solution.

  Examples of the charge generation material include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, and phthalocyanine pigments. It is not something. These charge generating substances can be used alone or in a form dispersed in a known resin.

  As the binder resin of the charge generation layer, a known resin can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin) and poly-vinylcarbazole resin, but are not limited thereto.

  The charge generation layer is formed by dispersing a charge generation material in a solution in which a binder resin is dissolved in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a certain film thickness using a coating device. It is preferable to prepare the film by drying.

  Solvents for dissolving and coating the binder resin used in the charge generation layer include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol , Butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like, but are not limited thereto.

  As a means for dispersing the charge generating material, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The mixing ratio of the charge generating material to the binder resin is preferably 1 to 600 parts by weight, more preferably 50 to 500 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. It should be noted that the coating solution for the charge generation layer can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. The pigment can also be formed by vacuum deposition.

(Charge transport layer)
The charge transport layer used in the photosensitive layer according to the present invention contains a charge transport material and a binder resin, and is formed by dissolving and coating the charge transport material in a binder resin solution.

  Charge transport materials include, for example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds Oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1- Two or more kinds of vinylpyrene and poly-9-vinylanthracene may be mixed and used.

  As the basic structure of the charge transport material, a triphenylamine derivative, a styryl compound, a benzidine compound, a butadiene compound, and the like can be used, and among them, a styryl compound is preferable.

  A known resin can be used as the binder resin for the charge transport layer, and polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, and styrene-methacrylic acid. Examples include ester copolymer resins, and polycarbonate is preferred. Further, BPA, BPZ, dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The charge transport layer is preferably formed by dissolving the binder resin and the charge transport material to prepare a coating solution, applying the coating solution to a certain film thickness with a coating machine, and drying the coating film.

  Examples of the solvent for dissolving the binder resin and the charge transport material include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, Examples thereof include, but are not limited to, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, pyridine, and diethylamine.

  The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  An antioxidant, an electronic conductive agent, a stabilizer and the like may be added to the charge transport layer. The antioxidants described in Japanese Patent Application No. 11-200135 and the electronic conductive agents described in Japanese Patent Application Laid-Open Nos. 50-137543 and 58-76483 are preferable.

(Image forming device)
The image forming apparatus of the present invention comprises a contact charger for contacting the surface of an electrophotographic photosensitive member formed by sequentially laminating a photosensitive layer and a surface layer on a conductive support to charge the surface of the electrophotographic photosensitive member, Image exposing means for forming an electrostatic latent image on the electrophotographic photosensitive member, developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and developed on the electrophotographic photosensitive member An image forming apparatus including a transfer unit that transfers a toner image.

  Hereinafter, the components and configuration of the image forming apparatus will be described.

[Contact charging device]
As the contact charging device according to the present invention, various charging members such as a magnetic brush method, a charging roller method, and a blade method can be used. Among these, a charging roller method or a magnetic brush method is preferably used in the present invention. . That is, a charging roller or a magnetic brush that is easy to obtain charging uniformity is preferable. The charging roller type and magnetic brush type charging means will be described below.

  In the present invention, a charging roller composed of a conductive elastic member can be brought into contact with a photosensitive member (image carrier), and a voltage can be applied to the charging roller to charge the photosensitive member (image carrier).

  Such a charging roller system may be either a DC charging system in which a DC voltage is applied to the roller or an induction charging system in which an AC voltage is applied to the roller.

  In addition, the frequency f of the voltage applied by the induction charging method is arbitrary, but in order to prevent strobing, that is, a stripe pattern, an appropriate frequency f is used according to the relative speed of the conductive elastic roller and the image carrier member. The frequency can be selected. The relative speed can be determined by the size of the contact area between the conductive elastic roller and the image carrier.

  The conductive elastic roller is formed by coating the outer periphery of a metal core with a layer made of a conductive elastic member (also simply referred to as a conductive elastic layer or H or a conductive rubber layer).

  Examples of the rubber composition that can be used for the conductive rubber layer include polynorbornene rubber, ethylene-propylene rubber, chloroprene rubber, acrylonitrile rubber, and silicone rubber. These rubber | gum can be used individually or as 2 or more types of mixed rubbers.

  In order to impart conductivity, a conductivity imparting agent is blended with these rubber compositions. Examples of suitable conductivity imparting agents include known carbon black (furnace carbon black or ketien black), metal powder such as tin oxide. The usage-amount of an electroconductivity imparting agent is about 5 to about 50 mass parts with respect to the rubber composition whole quantity.

In addition to the rubber base material, the foaming agent, and the conductivity imparting agent, the rubber composition may be blended with a rubber chemical and a rubber additive as necessary to obtain a conductive foamed rubber composition. Rubber chemicals and rubber additives include vulcanizing agents such as sulfur and peroxide, vulcanization accelerators such as zinc white and stearic acid, vulcanized sulfenamide, thyrium, thiazole and granidine Accelerators, amine-based, phenol-based, sulfur-based, phosphorus-based anti-aging agents, antioxidants, UV absorbers, ozone degradation inhibitors, tackifiers, etc. can be used, and various reinforcing agents In addition, an inorganic filler such as a friction coefficient modifier, silica, talc, clay and the like can be arbitrarily selected and used. These conductive rubber layers preferably have a DC volume resistivity in the range of 10 ³ to 10 ⁷ Ωcm.

  Further, on the outside of these conductive elastic layers, a releasable coating layer may be provided for the purpose of preventing the toner remaining on the surface of the photoreceptor from adhering to the charging member. The coating layer also prevents oil seepage from the elastic layer and cancels the resistance unevenness of the elastic layer, uniforms the resistance, protects the surface of the charging roller, and adjusts the hardness of the charging roller. Etc.

The covering layer may be any layer as long as it satisfies the above physical properties, and may be a single layer or a plurality of layers. Examples of the material include resins such as hydrin rubber, urethane rubber, nylon, polyvinylidene fluoride, and polyvinylidene chloride. Moreover, it is preferable that the thickness of a coating layer is 100-1000 micrometers, and it is preferable that resistance value is 10 < ⁵ > -10 < ⁹ > (omega | ohm) * cm. Moreover, it is preferable that resistance value becomes large as it approaches the surface layer. Examples of the method for adjusting the resistance include adding a conductive material such as carbon black, metal, and metal oxide to the coating layer.

  In order to adjust the surface roughness Rz of the charging roller according to the present invention, it is preferable to include powder in the surface layer (conductive elastic layer or coating layer) of the charging roller. The granular material used in the present invention may be either an inorganic substance or an organic substance, but in the case of an inorganic substance, silica powder is particularly preferable. In the case of organic substances, for example, urethane resin particles, nylon particles, silicone rubber particles, epoxy resin particles and the like can be mentioned. These particles are used alone or in combination of two or more. A suitable particle may be selected from a material that can adjust the surface roughness Rz of the surface layer to a range of 0.05 to 10.0 μm. The degree range is easy to achieve. If the particle diameter exceeds 20 μm, the surface roughness Rz also exceeds 10.0 μm, which does not fulfill the intended purpose.

  The reason why the surface roughness Rz is set in the range of 0.05 to 10.0 μm is that if it exceeds 10.0 μm, filming of the toner on the roller surface becomes remarkable, and if it is less than 0.05 μm, the charging roller This is because the adhesion between the photosensitive drum and the photosensitive drum is increased, that is, the contact area is increased, so that charging noise cannot be suppressed.

  It is preferable to mix and disperse | distribute the mixture ratio in the surface layer of a powder in the ratio of about 5 to about 20 mass parts with respect to 100 mass parts of resin.

  The charging roller according to the present invention can be manufactured, for example, as follows. That is, first, a metal rotating shaft (core metal) is placed in a forming die having a cylindrical forming space, a conductive elastic layer forming material is filled in the forming die, and vulcanization is performed, whereby the outer periphery of the rotating shaft is filled. A conductive elastic layer is formed on the surface. Next, the rotating shaft on which the conductive elastic layer is formed is taken out from the mold.

  On the other hand, a material such as a urethane resin and granules, a conductivity-imparting agent and other additives are blended, and this blend is mixed and stirred using a ball mill or the like to prepare a surface layer forming material mixture. Then, the mixture is applied to the surface of the rotating shaft on which the conductive elastic layer is formed by a dip method, a roll coating method, a spray coating method, etc., dried to a uniform thickness, and heat-cured to form a two-layer structure. A charging roller can be manufactured.

  The charging roller thus obtained is formed so that the surface roughness Rz of the outermost surface layer is 0.05 to 10.0 μm.

  Next, the developer toner and development conditions used in the present invention will be described.

  In the developing method according to the present invention, the electrostatic latent image on the image carrier can be developed using either a one-component developer or a two-component developer. The one-component developer is composed of a magnetic toner composed of at least a magnetic powder and a binder resin, and may contain a colorant.

Further, the developing method can be used either in contact or non-contact. When a non-contact development method is employed, normal development without contact or reversal development without contact can be performed. The DC developing electric field at that time is 1 × 10 ³ to 1 × 10 ⁵ V / cm in absolute value, preferably 5 × 10 ³ to 1 × 10 ⁴ V / cm, and development is less than 10 ³ V / cm. Insufficient image density is obtained, and if it exceeds 10 ⁵ V / cm, the image quality is rough and fogging occurs.

  Next, the AC bias is 0.5 to 4 kV (pp), preferably 1 to 3 kV (pp), and the frequency is 0.1 to 10 kHz, preferably 2 to 8 kHz.

  When the AC bias is less than 0.5 kV (pp), the toner attached to the carrier does not come off, non-contact development becomes insufficient, and the image density becomes insufficient. On the other hand, when the AC bias exceeds 4 kV (pp), carriers in the developer fly and cause carrier adhesion on the photosensitive member.

  Further, if the frequency of the AC bias is less than 0.1 kHz, the toner is not sufficiently detached from the arrow carrier, resulting in insufficient development and a decrease in image density. On the other hand, if the frequency of the AC bias exceeds 10 kHz, the toner cannot follow the fluctuation of the electric field, resulting in poor arrow development and a decrease in image density.

[Configuration of image forming apparatus]
Hereinafter, description will be made with reference to the drawings. FIG. 1 is a diagram illustrating an example of an image forming apparatus that performs roller charging. This image forming apparatus is for practicing the present invention, and is charged by bringing a charging roller into contact with a photosensitive drum on a belt electrode for forming an electrostatic latent image, and for transferring toner onto a transfer sheet. A transfer roller is used as the transfer pole, and the transfer roller is brought into contact with the photosensitive drum directly or with the transfer paper interposed therebetween, so that the generation of ozone is avoided. The electrostatic latent image is developed by non-contact development.

  In FIG. 1A, an electrostatic latent image is formed on the photosensitive drum 2 charged by the charging roller 1. The electrostatic latent image is developed into a toner image by a developing sleeve 4 that is a developer carrying member of the developing device 3 disposed in the vicinity of the photosensitive drum 2. Then, after the charge of the photosensitive drum 2 is discharged by the discharging lamp 5 before transfer, the toner image is transferred to the transfer paper P transported by the transporting roller 8 from the paper feed cassette and transferred to the transfer paper 6 by the reverse polarity of the toner. The toner is transferred onto the transfer paper P by the electrostatic force of the reverse polarity charge. After the toner transfer, the transfer paper P is separated from the photosensitive drum 2 and then sent to the fixing device by the conveyance belt 7, and the toner image is fixed to the transfer paper P by the heating roller and the pressing roller.

  A bias voltage composed of DC and AC components is applied to the charging roller 1 (and transfer roller 6) from a power source 9 (10), and the charging of the photosensitive drum 2 and the toner image are generated in a state where the amount of ozone generation is extremely small. Transfer onto the transfer paper P is performed. The bias voltage is usually composed of a DC bias of ± 500 to 1000 V and an AC bias of 100 Hz to 10 KHz and 200 to 3500 V (pp) superimposed thereon.

  The charging roller 1 and the transfer roller 6 is driven or forced rotation under pressure to the photosensitive drum 2.

  The pressure contact with the photosensitive drum 2 is 10 to 100 g / cm, and the rotation of the roller is 1 to 8 times the peripheral speed of the photosensitive drum 2.

  As shown in FIG. 1B, the charging roller 1 (and the transfer roller 6) includes a cored bar 20 and a rubber layer such as chlorprene rubber, urethane rubber, and silicone rubber that are conductive elastic members provided on the outer periphery thereof. Or it consists of those sponge layers 21, Preferably it is comprised by providing the protective layer 22 which consists of a mold release fluorine-type resin or silicone resin layer of 0.01-1 micrometer thickness in the outermost layer.

  Photosensitive drum 2 after the transfer is cleaned by pressure contact of the cleaning blade 12 of the cleaning unit 11 is equipped for the next image formation.

  As an image forming apparatus, a photosensitive member and components such as a developing device and a cleaning device may be integrally combined as a process cartridge, and this unit may be configured to be detachable from the apparatus main body. In addition, at least one of an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge, and a single unit that can be attached to and detached from the apparatus main body, and a rail of the apparatus main body, etc. It is good also as a structure which can be attached or detached using the guide means.

  In FIG. 1, a roller charger is used for both the charger and the transfer electrode. However, in the present invention, transfer means other than the transfer roller may be used for the transfer electrode.

  Next, the magnetic particles forming the charging magnetic brush will be described.

  FIG. 2 is a diagram of a contact-type magnetic brush charging device, and FIG. 3 is a diagram showing a relationship between an AC bias voltage and a charging potential by the charging device of FIG.

  In general, when the volume average particle diameter of magnetic particles forming the charging magnetic brush is large, (a) the state of the ears of the magnetic brush formed on the charging magnetic particle carrier (conveyance carrier) is rough. be charged while applying vibration, easily unevenness appears in a magnetic brush, a problem of uneven charging occurs. In order to solve this problem, the volume average particle diameter of the magnetic particles may be reduced. As a result of the experiment, the effect starts to appear when the volume average particle diameter is 200 μm or less, and particularly when the volume average particle diameter is 150 μm or less, the magnetic brush is qualitatively improved. The problems associated with the coarseness of the ears are eliminated. However, if adapted to adhere to the photosensitive drum 50 surface during charged particle is too small, or is easily scattered. These phenomena relate to the strength of the magnetic field acting on the particles and the magnetization strength of the particles, but generally, the volume average particle diameter of the particles becomes noticeable at 20 μm or less.

  From the above, the magnetic particles have a volume average particle size of 200 μm or less, 20 μm or more, and 30% by number or less of magnetic particles having a particle size of 1/2 or less of the number average particle size of the magnetic particles. It is necessary to. The magnetization strength is preferably 30 to 100 emu / g.

  Such magnetic particles are the same as the magnetic carrier particles of the conventional two-component developer described above as the magnetic material, such as metals such as iron, chromium, nickel and cobalt, or their compounds and alloys, such as iron tetroxide. , Γ-ferric oxide, chromium dioxide, manganese oxide, ferrite, manganese-copper alloys, ferromagnetic particles, or the surfaces of these magnetic particles are made of styrene resin, vinyl resin, ethylene resin Particles obtained by coating with a resin such as rosin-modified resin, acrylic resin, polyamide resin, epoxy resin, polyester resin, or made of resin containing dispersed magnetic fine particles are conventionally known. It can be obtained by selecting the particle size with an average particle size selecting means.

  In addition, forming the magnetic particles in a spherical shape has an effect that the particle layer formed on the carrier is uniform, and a high bias voltage can be uniformly applied to the carrier. That is, the magnetic particles are spherical. (1) Generally, magnetic particles are easily magnetized and adsorbed in the long axis direction, but their directionality is lost due to the spherical shape. Therefore, the magnetic particle layer is uniformly formed. (2) With the increase in resistance of magnetic particles, the edge portion as found in conventional particles is eliminated, and the electric field to the edge portion is prevented. Concentration does not occur, and as a result, even when a high bias voltage is applied to the carrier for charging magnetic particles, the surface of the photosensitive drum 50 is uniformly discharged and charging unevenness does not occur.

Spherical particles that exhibit the above effects are preferably those in which conductive magnetic particles are formed so that the resistivity of the magnetic particles is 10 ⁵ to 10 ¹⁰ Ωcm. The resistivity after tapping putting particles in a container having a sectional area of 0.50 cm ^2, a load of 1 kg / cm ² on packed particles, 1000V / cm between the load and a bottom electrode This value is obtained by reading the current value when a voltage generating an electric field is applied. If this resistivity is low, when a bias voltage is applied to the carrier, charges are injected into the magnetic particles, and the Magnetic particles are likely to adhere to the surface of the body drum 50, or dielectric breakdown of the photosensitive drum 50 due to a bias voltage is likely to occur. If the resistivity is high, charge injection is not performed and charging is not performed.

  Furthermore, the magnetic particles used in the contact-type magnetic brush charging device 120 have a small specific gravity and an appropriate maximum magnetization so that the magnetic brush formed by the magnetic brush is moved easily by an oscillating electric field and no external scattering occurs. It is desirable to have Specifically, it has been found that good results can be obtained when the true specific gravity is 6 or less and the maximum magnetization is 30 to 100 emu / g, particularly 40 to 80 emu / g.

In summary, the magnetic particles are spheroidized so that the ratio of the major axis to the minor axis is 3 times or less, there are no protrusions such as needles and edges, and the resistivity is preferably 10 It is desired to be in the range of ⁵ to 10 ¹⁰ Ωcm. For such spherical magnetic particles, select spherical particles as much as possible for magnetic particles, and for magnetic particles dispersed particles, use magnetic particles as much as possible, and perform spheronization after forming dispersed resin particles. Or by forming dispersed resin particles by a spray drying method.

  According to FIG. 2 or FIG. 3, the magnetic brush charging device 120 as a charging device faces the rotating photoconductor drum 50 and is in the same direction (counterclockwise) at a proximity portion (charging unit T) with the photoconductor drum 50. A cylindrical charging sleeve 120a using, for example, an aluminum material or a stainless material, and a magnet body 121 made of N and S poles provided inside the charging sleeve 120a, A magnetic brush made of magnetic particles formed on the outer peripheral surface of the charging sleeve 120 a by the magnet body 121 and charging the photosensitive drum 50, and a magnetic brush on the charging sleeve 120 a at the NN magnetic pole portion of the magnet body 121 are scraped. The scraper 123 to be taken and the magnetic particles in the magnetic brush charging device 120 are stirred or supplied to the magnetic brush charging device 120 when the magnetic particles are supplied. And stirring screw 124 to discharge overflowing from the discharge port 125, constituted by the bristles regulating plate 126 of the magnetic brush. The charging sleeve 120a is rotatable with respect to the magnet body 121, and is 0.1 to 1.0 times in the same direction (counterclockwise) as the movement direction of the photosensitive drum 50 at a position facing the photosensitive drum 50. It is preferably rotated at a peripheral speed. As the charging sleeve 120a, a conductive carrier capable of applying a charging bias voltage is used. In particular, the magnet body 121 having a plurality of magnetic poles inside the conductive charging sleeve 120a having a particle layer formed on the surface thereof. Those having a structure provided with are preferably used. In such a carrier, the magnetic particle layer formed on the surface of the conductive charging sleeve 120a moves up and down in a wave shape due to the relative rotation with the magnet body 121. Even if the magnetic particle layer on the surface of the charging sleeve 120a is somewhat uneven in thickness, the influence is sufficiently covered so as not to cause a problem due to the wavy undulations. The surface of the charging sleeve 120a preferably has an average surface roughness of 5.0 to 30 [mu] m for stable and uniform transfer of magnetic particles. If the surface is smooth, the surface cannot be sufficiently transported. Overcurrent flows from the part, and in any case, uneven charging tends to occur. Sand blasting is preferably used to achieve the above surface roughness. Further, the outer diameter of the charging sleeve 120a is preferably 5.0 to 20 mm. This ensures a contact area necessary for charging. If the contact area is larger than necessary, the charging current becomes excessive, and if it is small, charging unevenness is likely to occur. When the diameter is small as described above, magnetic particles are likely to be scattered or adhere to the photosensitive drum 50 due to centrifugal force. Therefore, the linear velocity of the charging sleeve 120a is almost the same as the moving velocity of the photosensitive drum 50, or more It is also preferable that it is slow.

Further, the thickness of the magnetic particle layer formed on the charging sleeve 120a is preferably a thickness that is sufficiently scraped off by the regulating means to form a uniform layer. If there is too much magnetic particles on the surface of the charging sleeve 120a in the charging region, the magnetic particles will not vibrate sufficiently, causing photoconductor wear and charging unevenness and overcurrent easily flowing, and driving torque of the charging sleeve 120a. Has the disadvantage of becoming larger. On the other hand, if the amount of the magnetic particles on the charging sleeve 120a in the charged region of the magnetic particles is too small, an incomplete portion is formed in contact with the photosensitive drum 50, and adhesion of the magnetic particles on the photosensitive drum 50 or uneven charging occurs. become. Result of repeated experimentation, the preferred deposition amount of the magnetic particles in the charging area is 100 to 400 mg / cm ^2, particularly preferably has proven 200-300 mg / cm ^2. This adhesion amount is an average value in the charging region of the magnetic brush.

The magnetic brush charging device 120 serving as a charging device includes a charging bias in which an alternating current (AC) bias AC3 is superimposed on a direct current (DC) bias E3 as necessary, for example, a direct current bias E3 having the same polarity as the toner (in this embodiment, minus). -100 to-500V polarity) is also frequency 1~5kHz as AC bias AC3, the charging sleeve 120a which charging bias voltage 300~500V _P-P is applied, contacting the peripheral surface of the photosensitive drum 50 is slidingly The photosensitive drum 50 is charged by rubbing. Since an oscillating electric field is formed between the charging sleeve 120a and the photosensitive drum 50 by applying the voltage of the AC bias AC3, the electric charge is smoothly injected onto the photosensitive layer 10a through the magnetic brush. High-speed charging is performed uniformly.

  The magnetic brush on the charging sleeve 120a charged with the photosensitive drum 50 is dropped from the charging sleeve 120a by the scraper 123 at the NN magnetic pole portion provided in the magnet body 121, and the charging sleeve 120a in the vicinity of the charging sleeve 120a. Then, the magnetic brush is formed again and conveyed to the charging unit T after being stirred by the stirring screw 124 rotating in the opposite direction (counterclockwise).

As shown in FIG. 3, the relationship between the peak-to-peak voltage of the AC bias AC3 of the charging bias and (V _P-P) and the charging potential, the charge potential is increased in accordance with the peak-to-peak voltage V _P-P increases, The charging potential is saturated at a constant peak-to-peak voltage V1 and approximately equal to the value VS of the DC bias E3 of the charging bias, and the charging potential hardly changes even if the peak-to-peak voltage _VP-P is further increased. There is a characteristic. Although the electric resistance of the magnetic particles varies depending on the environmental conditions, the electric resistance increases as the toner is fused to the surface of the magnetic particles as it is used. For this reason, the characteristic curve is shown on the left side as shown by a solid line in the case of new magnetic particles in the initial stage of use, and the characteristic curve is shown on the right side as shown in FIG. Will be located.

In the charging device using the contact method of the image forming apparatus of the present invention, the voltage value of the DC bias E3 corresponding to the charging potential is set to a predetermined value when the mounted power source is turned on or before printing is started, and the peak-to-peak voltage (V A charging bias gradually increasing from a low value ( _PP ) is applied, and the charging potential of the photosensitive drum 50 that changes at that time is detected by an electrometer ES. The detected charging potential is converted into a digital value by an A / D converter and then input to a control unit (CPU). In the control unit, the value of VP _-P when the charged potential reaches the saturation point of the predetermined value VS is defined as an appropriate bias value V1, and the printing operation is performed.

That is, when printing is performed, the AC bias AC3 is gradually increased (swept) from a low value to obtain the value V1 of VP _-P of the AC bias AC3, and a bias signal is output from the control unit. This control signal is converted to an analog value by the D / A converter and then sent to the AC bias AC3. The AC bias AC3 outputs the determined peak-to-peak voltage V1. At this time, the value of the peak-to-peak voltage V1 and the specified value V2 to be exchanged due to the deterioration of the magnetic particles stored in the memory are read and compared. Since the resistance of the magnetic particles increases due to toner mixing, the proper bias value V1 increases as the print is used. Along with this, _{VP-P to} be applied increases, and an unchargeable state occurs. The image formation is continued while the measured voltage value is smaller than the prescribed value V2 indicating that charging is not possible. However, when the measured voltage value is larger than the prescribed value V2, an image forming operation stop signal is sent from the control unit to stop the image forming operation. The charging unit abnormality is displayed on the display unit of the operation unit. Based on this display, the charging magnetic particle supply bottle 220 is set in the magnetic brush charging device 120, and an opening / closing lid (not shown) on the bottom of the supply bottle 220 is opened to drop and supply the magnetic particles to the magnetic brush charging device 120. To do. In the above description, the electrometer ES is used to measure the potential of the photosensitive drum 50. When the DC bias ammeter is connected to the bias power source and the AC bias _VP-P is changed, the current value reaches the saturation point. _VP-P may be set to an appropriate bias value V1, compared with a specified value V2, and magnetic particles may be supplied when V1 is exceeded.

  Also, during periodic maintenance and the like during or for example 50,000 prints, replacement of the magnetic particles for charging is carried out. At each maintenance print stored in the memory or at regular intervals of, for example, 50,000 prints, an exchange signal is output through the control unit, and supply of the charging magnetic particle supply bottle 220 set in advance by driving a drive motor (not shown) roller 221 is rotated, the magnetic particles in the supply bottle 220 is the total amount in the magnetic brush charging device 120 is dropped once. It is also possible to control the image forming apparatus to be in an operating state by removing the empty supply bottle 220 after supply and setting a new supply bottle 220. In addition, a supply signal such as blinking of a lamp is displayed on the operation unit (not shown) from the control unit at regular intervals, the supply bottle 220 is set on the magnetic brush charging device 120, and an open / close lid (not shown) on the bottom of the supply bottle 220 is opened. Then, magnetic particles may be supplied.

  The dropped magnetic particles are conveyed by the rotating charging sleeve 120a, scraped off from the surface of the charging sleeve 120a by the scraper 123, and replenished to the bottom of the magnetic brush charging device 120. Accordingly, the used magnetic particles stored in the magnetic brush charging device 120 are overflowed from the discharge port 125 by the stirring screw 124 rotated counterclockwise, and the common magnetic particle recovery container 300 is passed through the duct DB. To be recovered. At this time, the supply amount of the magnetic particles supplied from the supply bottle 220 into the magnetic brush charging device 120 is preferably 20 to 50% by mass with respect to all the magnetic particles stored in the magnetic brush charging device 120. If the amount is less than 20% by mass, the amount of newly supplied magnetic particles is so small that there is no exchange effect and good charging is not performed. If the amount exceeds 50% by mass, new magnetic particles overflow.

  The above, good charging performance without magnetic particles in the charging device is deteriorated is maintained long term.

  FIG. 4 is a cross-sectional view showing an example of an image forming apparatus having a magnetic brush charger. In FIG. 4, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image bearing member. An organic photosensitive layer is applied on the drum, and a resin layer is coated thereon. The photosensitive member is grounded and rotated clockwise. Is done. Reference numeral 52 denotes a magnetic brush charger that can uniformly charge the circumferential surface of the photosensitive drum 50. Prior to charging by the charger 52, in order to eliminate the history of the photoconductor in the previous image formation, exposure by the exposure unit 51 using a light emitting diode or the like may be performed to neutralize the peripheral surface of the photoconductor.

  Image exposure based on an image signal is performed by the later image exposure unit 53 uniformly charging the photosensitive member. The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

  The electrostatic latent image is then developed by the developing device 54. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The developer is, for example, a carrier composed of the above-mentioned ferrite as a core and coated with an insulating resin around it, and a coloring material such as carbon black, a charge control agent, and a low molecular weight polyolefin mainly composed of the above-mentioned styrene acrylic resin. It consists of toner with silica, titanium oxide, etc. added externally to the particles. The developer is regulated to a layer thickness of 100 to 600 μm on the developing sleeve 541 by a layer forming means (not shown) and conveyed to the developing area. Then, development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor.

  The transfer material (also referred to as “recording paper”) P is fed to the transfer area by the rotation operation of the feed roller 57 at the time when the transfer timing is ready after the image formation.

  In the transfer area, a transfer roller (transfer device) 58 is pressed against the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the transferred transfer material P is sandwiched and transferred.

  Next, the transfer material P is neutralized by a separation brush (separator) 59 brought into a pressure contact state almost simultaneously with the transfer roller, separated by the peripheral surface of the photosensitive drum 50, conveyed to the fixing device 60, and pressed against the heat roller 601. heating the roller 602, and is discharged to the outside of the apparatus through the discharge rollers 61 after welded toner by pressure. The transfer roller 58 and the separation brush 59 are separated from the peripheral surface of the photosensitive drum 50 after the transfer material P has passed, and prepare for the formation of the next toner image.

  On the other hand, the photosensitive drum 50 after separating the transfer material P is subjected to removal and cleaning of residual toner by pressure contact of the cleaning blade 621 of the cleaning device 62, and after receiving the charge removal by the exposure unit 51 and charging by the charger 52 again. The image forming process is entered.

  Incidentally, 70 is a photoreceptor, a charger, a detachable process cartridge is integrated transcription unit-separator and a cleaning device.

  As the image forming apparatus, the above-described photosensitive member and components such as a developing device and a cleaning device may be integrally coupled as a process cartridge, and this unit may be configured to be detachable from the apparatus main body. In addition, a process cartridge is formed by integrally supporting at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device together with a photosensitive member, and a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  When the image forming apparatus is used as a copying machine or a printer, image exposure is performed by irradiating the photosensitive member with reflected light or transmitted light from a document or by reading a document with a sensor and generating a laser beam according to this signal. scan, driving an LED array, or carried out, such as by irradiating light to the photosensitive body performs driving of the liquid crystal shutter array.

  In the case of using as a facsimile printer, the image exposure device 13 carries out an exposure for printing received data.

  The image forming apparatus of the present invention can be applied to general electrophotographic apparatuses such as copying machines, laser printers, LED printers, and liquid crystal shutter printers. Furthermore, the display, recording, light printing, The present invention can be widely applied to apparatuses such as plate making and facsimile.

The image forming method according to the present invention is characterized in that when forming an electrostatic latent image on a photoreceptor, image exposure is performed using an exposure beam having a spot area of 2000 μm ² or less. Even if such a small spot exposure beam is used, the organophotoreceptor according to the present invention can faithfully form an image corresponding to the spot area. A more preferable spot area is 100 to 800 μm ² . As a result, an electrophotographic image having a gradation of not less than 800 dpi (dpi is the number of dots per 2.54 cm) can be achieved.

The spot area of the exposure beam is a light intensity distribution plane that appears on the cut surface when the exposure beam is cut along a plane perpendicular to the beam, and is in a region where the light intensity is 1 / e ² or more of the maximum peak intensity. It means the corresponding area.

Examples of the light beam used include a scanning optical system using a semiconductor laser, and a solid state scanner such as an LED or a liquid crystal shutter. The light intensity distribution includes a Gaussian distribution and a Lorentz distribution, but 1 / e of each peak intensity. A portion up to ² is defined as a spot area.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means “part by mass”.

(Preparation of photoreceptor 1)
Photoreceptor 1 was produced as follows.

  The surface of a cylindrical aluminum support having a diameter of 60 mm was cut to prepare a conductive support having a surface roughness Rz = 1.5 (μm).

<Intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; using a lime mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Titanium oxide SMT500SAS (manufactured by Teika) 3 parts Methanol 10 parts Dispersion was carried out for 10 hours in a batch manner using a sand mill as a disperser.

  On the support by using the above coating solution was applied by dip coating to a dry film thickness of 2 [mu] m.

<Charge generation layer>
Charge generation material: titanyl phthalocyanine pigment (titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts polyvinyl butyral resin (# 6000-C: Electrochemical Industry) 10 parts) t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

<Charge transport layer>
Charge transport material (4,4′-dimethyl-4 ″-(β-phenylstyryl) triphenylamine) 225 parts Binder: Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Irganox 1010: manufactured by Ciba Geigy Japan) ) 6 parts THF (tetrahydrofuran) 1600 parts Toluene 400 parts Silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part was mixed and dissolved to prepare a charge transport layer coating solution. A charge transporting layer having a dry film thickness of 20 μm was formed by coating with a circular slide hopper coating machine.

<Surface layer>
As the metal oxide particles, aluminum oxide having a number average primary particle size of 15 nm is used, the exemplified compound (S-15) is used as the compound having a reactive organic group, and the compound having a reactive organic group is used as shown below. A surface treatment was prepared.

  First, a mixed solution of 100 parts of aluminum oxide particles having a number average primary particle diameter of 15 nm, 100 parts of the above exemplary compound (S-15), and 300 parts of a mixed solvent of toluene / isopropyl alcohol = 1/1 (mass ratio) is obtained. The mixture was placed in a sand mill together with the beads at about 40 ° C. and stirred at a rotational speed of 1500 rpm, and surface treatment was performed with a compound having a reactive organic group of aluminum oxide particles. Further, the above treatment mixture is taken out, put into a Henschel mixer, stirred for 15 minutes at a rotation speed of 1500 rpm, and then dried at 120 ° C. for 3 hours to complete the surface treatment of the aluminum oxide particles with the compound having a reactive organic group. Thus, surface-treated aluminum oxide 1 was obtained. By the surface treatment with the compound having a reactive organic group, the particle surface of the aluminum oxide particles was coated with the compound having a reactive organic group.

  The surface treatment amount of the compound having a reactive organic group at this time (the coating amount of the compound having a reactive organic group) is 15% by mass with respect to the aluminum oxide particles (that is, reactive with respect to 100 parts by mass of the aluminum oxide particles). The surface treatment amount of the compound having an organic group was 40 parts by mass).

  Subsequently, a surface layer was formed by the following method.

Surface-treated aluminum oxide oxide particles 1 (surface-treated with S-15) 100 parts Curing compound (Exemplary Compound 43) 100 parts Polymerization initiator (Exemplary Compound 1-6) 30 parts n-propyl alcohol 400 parts Were mixed and stirred and sufficiently dissolved and dispersed to prepare a surface layer coating solution. A surface layer was applied to the photoreceptor on which the coating solution had been prepared up to the charge transport layer using a circular slide hopper coater. After the coating, ultraviolet rays were irradiated for 1 minute using a metal halide lamp to obtain a surface layer having a dry film thickness of 2.0 μm.

[Preparation of photoconductors 2 to 13]
Photoreceptors 2 to 13 were produced by changing the production conditions of the photoreceptor 1 as shown in “Table 1” below.

[Performance evaluation]
(Image unevenness)
First, the photoconductors 1 to 13 prepared above are mounted on a digital color printer having a basic configuration of an image forming apparatus having a charging roller which is a contact charging apparatus shown in FIG. 1, and in a 10 ° C./15% RH environment. After adding a print history of 100,000 sheets with an image of 5% printing rate, the presence or absence of image quality defects (color points and streak) in the printed image was visually evaluated using the following criteria. .

  A: There are no vertical stripe-like defects and color spots on the image, and the printed image is good.

  ○: A thin vertical streak-like defect and a color point are slightly confirmed on the image.

  △: Although vertical streak-like defects on the image and the color point is confirmed, no practical problem.

  ×: vertical stripe-like defects on the image and color point number is confirmed, problems in practical use.

(Real machine durability test on the photoreceptor surface)
Next, a print history of 400,000 actual shots was added under the same conditions as described above, and the amount of surface abrasion (α value), surface scratches, and degree of discoloration were evaluated.

  Specifically, the following α value was evaluated.

α value = {(surface scraping amount in the depth direction [μm]) / (total drum rotation speed [rot.])}
× 100,000
That is, the smaller the α value, the higher the wear resistance.

  At the same time, the state of the photoreceptor surface was observed and visually evaluated for surface scratches and discoloration in 10 steps (0.5 increments) of (good) to 1 (bad).

  In addition, a photoconductor 10 is mounted on an apparatus obtained by remodeling a charging apparatus of a digital color printer based on an image forming apparatus having a charging roller shown in FIG. It was set to 3.

  As is apparent from the results shown in Table 2, Examples 1 to 11 using the photoreceptors 1 to 11 in the present invention have all the characteristics within the practical range, but the photoreceptors 12 and 11 outside the present invention are used. Comparative examples 1 and 2 were used, also, Comparative example 3 it can be seen that there is a problem in at least one of characteristics using scorotron.

  That is, according to the present invention, there is no scratch (scratch) or density unevenness (unevenness) on the surface of a photoreceptor even in long-term use in a charging process using a contact charging device, and electrophotography excellent in wear resistance and gas resistance. It can be seen that an image forming apparatus using a photoreceptor can be provided.

DESCRIPTION OF SYMBOLS 1 Charging roller 3 Developing device 4 Developing sleeve 5 Static elimination lamp 6 Transfer roller 7 Conveying belt 8 Conveying roller 9, 10 Power supply 11 Cleaning device 12 Cleaning blade 20 Core metal 50 Photosensitive drum (or photosensitive member)
51 Exposure Unit 52 Magnetic Brush Charger 53 Image Exposure Unit 54 Development Unit 57 Paper Feed Roller 58 Transfer Roller (Transfer Unit)
59 Separation brush (separator)
60 fixing device 61 paper discharge roller 62 cleaning device 70 process cartridge 120 magnetic brush charging device 120a charging sleeve 220 supply bottle 300 magnetic particle collection container ES electrometer 531 polygon mirror 532 reflection mirror 541 developing sleeve 601 heat roller 602 pressure roller 621 cleaning blade

Claims (4)

  Contact charging means for charging the surface of the electrophotographic photosensitive member by contacting the surface of the electrophotographic photosensitive member having a photosensitive layer and a surface layer on a conductive support; and an electrostatic latent image on the electrophotographic photosensitive member. An image provided with an image exposure means to be formed, a developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and a transfer means for transferring a toner image developed on the electrophotographic photosensitive member A forming apparatus, wherein the surface layer of the electrophotographic photosensitive member is surface-treated with a compound having at least a reactive organic group, and a curable compound capable of forming a chemical bond with the reactive organic group, An image forming apparatus characterized by containing a product obtained by reacting.   The image forming apparatus according to claim 1, wherein the compound having a reactive organic group is a silane compound having a reactive acryloyl group or a methacryloyl group.   The image forming apparatus according to claim 1, wherein the curable compound is an acrylic monomer or oligomer having an acryloyl group or a methacryloyl group. 4. The image forming apparatus according to claim 3, wherein the ratio of Ac / M of the molecular weight M of the acrylic monomer or oligomer having the acryloyl group or methacryloyl group to the number Ac of the acryloyl group or methacryloyl group is as follows. .
0.005 <Ac / M <0.012

Images