JP2008020661A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which prevents the occurrence of void images due to abnormal discharges and provides images that are high in quality. <P>SOLUTION: The image forming apparatus has a plurality of image carriers, an intermediate transfer body which moves in a prescribed direction and is capable of transmitting the whole or a part of the light, and a plurality of transfer means which successively electrostatically transfer the toner images, formed on the image carriers, to the intermediate transfer body. The transfer means has a discharge light detecting means 119 which has a transfer roller 105, containing an optical anisotropic material in the whole or a part in its thickness direction, is provided on the end part side of the transfer roller 105, and detects the discharge light, condensed at the end surface by the optical anisotropic material and generated at the time of the transfer, and a control means which controls the transfer conditions of the transfer means according to the information relating to the detected discharge light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus in an electrophotographic image forming method.

In recent years, electrophotographic image forming apparatuses capable of copying and printing full-color images have been put into practical use. The image forming apparatus includes an intermediate transfer body double transfer system (yellow (Y), magenta (M), cyan (C), and black (Bk) colors formed on an image carrier such as a photoconductor for each color. A system in which an image is sequentially superposed on an intermediate transfer member for primary transfer, and the primary-transferred full-color toner images are collectively transferred to a transfer material (hereinafter referred to as “intermediate transfer system”). It is preferably used because it is paper-free regardless of the type of paper and can be copied on the entire surface.
In the intermediate transfer type image forming apparatus, various image forming parts such as a photosensitive member, a secondary transfer roller, and a cleaning blade are brought into contact with the surface of the intermediate transfer member, and the surface of the intermediate transfer member is rubbed. For this reason, the intermediate transfer body is required to have durability against mechanical and electrical external forces due to a rubbing action and an electric action with the image forming component. In particular, as the intermediate transfer member, the surface characteristics represented by the wear resistance of the surface of the intermediate transfer member, the releasability to toner, the friction coefficient of the surface of the intermediate transfer member with the image forming component, and the tension The mechanical properties represented by the elastic modulus and elongation rate are important.
Conventionally, as a material for an intermediate transfer member having good releasability with respect to toner or the like, a silicone-based resin or elastomer (for example, see Patent Documents 1 to 5), a polyolefin-based material (for example, see Patent Documents 6 and 7, etc.) ) Etc. are known.
However, in this case, there is a problem that it is impossible to prevent the surface of the intermediate transfer member from being worn or scratched.
Conventionally, fluorine-based resins and elastomers are known as materials for intermediate transfer members having excellent releasability (see, for example, Patent Documents 8 to 12).
However, in this case, when used as a surface layer material of an intermediate transfer member, there is a problem that the surface layer material is peeled off from the substrate due to poor adhesion to the substrate.
Further, as materials for intermediate transfer members having excellent mechanical properties, polycarbonate-based materials (for example, see Patent Documents 13 to 17), polyester-based materials (for example, see Patent Documents 18 and 19), polyurethane-based materials (for example, Patents) Documents 20 and 21, etc.), polyimide materials (see Patent Documents 22 to 26, etc.), materials in which fluorine resin fine particles and fluorine organic compounds are dispersed in polyimide (for example, see Patent Documents 27 to 29, etc.) Are known.
However, in this case, the releasability with respect to the toner or the like is not sufficient, and there is a problem that the toner particles, the additive thereof, and the like adhere to the surface of the intermediate transfer member.

Further, in the intermediate transfer type image forming apparatus, the toner transfer rate during the primary transfer of transferring the toner image from the photosensitive member to the intermediate transfer member and during the secondary transfer of transferring from the intermediate transfer member to a transfer material such as paper. There is a problem that an abnormal image is generated due to this. For example, in order to obtain a full-color image, it is necessary to superimpose a plurality of color toner images. In this case, the height of the superimposed toner (toner pile height) becomes high in double color or triple color. In some cases, white spot-like image omission (hereinafter referred to as white omission) may occur around the image. This is caused by a hollow character in which the primary transfer cannot be physically performed due to a high toner pile height in the image portion and a gap discharge in which the primary transfer cannot be performed electrostatically. Here, for the former physical hollow character, a technique of applying a lubricant to the surface of the intermediate transfer member has been proposed as described in Patent Document 30.
However, since no technique for quantifying this transient phenomenon has been established for gap discharge, an effective countermeasure means effective so far has not been established.

Therefore, conventionally, in order to prevent the occurrence of abnormal images due to white spots, for example, there is known a color electrophotographic apparatus that neutralizes a toner image transferred by a sheet peeling charger every time a toner image is transferred to an intermediate transfer medium. (See Patent Document 31). There is also known a full-color copying apparatus in which the transfer potential at the final transfer stage is made larger than the transfer potential immediately before, and a predetermined voltage is applied to the intermediate transfer medium while moving to each transfer stage (see Patent Document 32). Further, there is known an image forming apparatus provided with a means for discharging charges on the intermediate transfer body before reaching a means for transferring a visible image from the intermediate transfer body to a sheet (see Patent Document 33). Further, an insulating layer having a volume resistance of 1 × 10 ⁷ Ωcm or more and a hardness lower than the surface hardness of the photosensitive member is formed on the surface of the transfer roller, and a bias having a polarity opposite to that of the transfer bias is applied to adhere the toner. There is known an image forming apparatus having a function of removing the image (see Patent Document 34).
However, in these cases, there is a need to provide static elimination means, voltage application means, control means, a surface insulating layer having a specific volume resistance value, etc., which complicates the entire apparatus and hinders cost increase and downsizing. There was a problem of becoming.

Polyimide resin is a resin that excels in heat resistance, mechanical properties, chemical resistance, and radiation resistance. Therefore, various molding materials such as films and sheets, paints such as enamels for electric wires, electronic materials, and flexible prints. Widely used in applications such as substrates, heat-resistant substrates, semiconductor sealing materials, adhesives, organic-inorganic composites. Attempts have been made to achieve the purpose of improving physical properties by adding insulating fine particles to the polyimide resin. For example, improving heat resistance and reducing the coefficient of thermal expansion (see Patent Document 35) is disclosed, and improving slipperiness and running durability (see Patent Documents 36 and 37) is disclosed, and printability and heat resistance are disclosed. Imparting heat resistance and moisture-resistant adhesion (see Patent Document 38). In addition, when carbon black is dispersed in a polyimide resin, light shielding properties and conductivity can be obtained. Therefore, the conductive paint using conductivity as a black matrix of a color filter of a liquid crystal display device utilizing the light shielding properties. As a planar heating element, it is used as an electromagnetic wave absorbing sheet. As a method for producing a polyimide resin, generally, a method in which a solvent-soluble polyamic acid is first synthesized and heated to 300 ° C. or higher to form a polyimide is generally used. Therefore, in order to disperse the insulating fine particles in the polyimide resin, it is necessary to disperse the insulating fine particles in the polyamic acid solution. As a dispersion method, insulating fine particles are added to a polyamic acid solution and dispersed by a dispersing machine such as a sand mill or a ball mill, or insulating fine particles are added to a polyamic acid varnish in a semi-liquid state, and a three-roll roll is used. A direct dispersion method of kneading and dispersing is conceivable.
However, since the affinity between the insulating fine particles and the polyamic acid is very poor, when they are mixed, the insulating fine particles are aggregated and it is difficult to uniformly disperse them. The extremely viscous polyamic acid solution also makes uniform dispersion difficult. Therefore, a method of synthesizing polyamic acid in an insulating fine particle dispersion, that is, a method of preparing a polyamic acid solution by reacting a diamine compound and an acid anhydride compound in an organic polar solvent in which insulating fine particles are dispersed in advance is proposed. (See Patent Document 37).
However, even in this method, since the insulating particles have a strong cohesion force, the insulating particles aggregate, resulting in variations in resistance within the surface, causing local discharge and fluctuations in the belt charge. As a result, there are problems such as white spots and density unevenness, and the conventional technique cannot sufficiently prevent the white spots.

In an image forming process in a copying machine, a printer, or the like, a toner image developed on a photosensitive member is transferred to a transfer belt or paper by a transfer electric field formed between the photosensitive member and a transfer member (including an intermediate transfer member). Therefore, it is very important to grasp these electrical characteristics when manufacturing a transfer body or mounting it on an image forming apparatus.
These electrical characteristics are measured based on the JIS K 6911 method, and are most commonly evaluated using surface resistivity and volume resistivity. The surface resistivity is calculated by pressing an electrode (probe) against the surface of the sample and detecting the current flowing through the surface, and the volume resistivity is obtained by measuring the current flowing between the electrodes above and below the sample. As another surface resistance measuring method, as shown in FIG. 7, three contact terminals are brought into contact with a member to be measured and two of the terminals are electrically connected, and the other one terminal is connected. A method of obtaining surface resistivity by measuring the resistance between the two as a combined resistance in parallel has also been proposed (Patent Document 39).
On the other hand, it is empirically known that there is a correlation between the surface resistivity or volume resistivity of the transfer belt and the transfer image, and many belt members that actively control these values have been proposed. For example, in Patent Document 40, a transfer belt is constituted by three layers of an inner layer made of a medium-resistance rubber, a dielectric layer, and a surface layer made of a material having a lower specific resistivity than the dielectric layer, thereby achieving both paper conveyance and separation. At the same time, stable and good images can be obtained. Further, in Patent Document 41, a plurality of types of carbon having different conductivity are dispersed so as to be unevenly distributed in the film thickness direction with respect to the resin, and an intermediate for preventing image density unevenness by making the belt surface resistance higher than the back surface. A method for manufacturing a transfer belt has been proposed.
However, surface resistivity and volume resistivity are evaluated using millimeter-order electrodes and show macro electrical characteristics, so that the belt characteristics can be completely achieved only with measured values of surface resistivity and volume resistivity. There is a problem that it cannot be grasped. For example, even if the toner on the photoconductor is transferred under the same conditions using a belt having the same surface resistivity and volume resistivity, density unevenness that occurs in a halftone image or the like is a phenomenon in which the image appears white in some places ( In the end, in the development stage of the image forming apparatus, a toner image transfer experiment was conducted on various belt samples under various conditions, and the output image was observed. Work such as extracting a preferred belt has occurred. In particular, in recent years, with the expectation of its durability, there is a movement to use a seamless belt made of a single layer film of a thermosetting polyimide resin or a polyamideimide resin as an intermediate transfer member. When used, there is a tendency that abnormal images such as white spots and density unevenness tend to occur remarkably, and a good image cannot be obtained even when compared with a conventional intermediate transfer belt. From this situation, it is desirable to establish a more microscopic electrical property evaluation method. At the same time, process control based on the knowledge gained there is performed in real time, so that image formation that does not cause density unevenness or white spots occurs. There was a strong demand for equipment.

Japanese Patent Laid-Open No. 5-46035 JP-A-8-30117 JP-A-9-269676 Japanese Patent Laid-Open No. 10-20538 Japanese Patent Laid-Open No. 11-231678 JP-A-5-311016 JP 7-24912 A JP-A-5-40417 JP-A-6-234903 JP-A-7-92825 JP-A-8-267605 JP-A-10-166508 JP-A-6-93175 Japanese Patent Laid-Open No. 6-149081 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 10-10880 JP-A-13-31849 Japanese Patent Laid-Open No. 13-13801 Japanese Patent Laid-Open No. 13-18284 Japanese Patent Laid-Open No. 10-319727 Japanese Patent Laid-Open No. 11-30915 JP 7-156287 A JP-A-8-176319 Japanese Patent Laid-Open No. 11-24427 JP-A-11-170389 Japanese Patent Application Laid-Open No. 12-172085 Japanese Patent Laid-Open No. 11-156971 JP 11-119560 A JP 7-156287 A Japanese Unexamined Patent Publication No. 8-21755 JP-A-1-282571 JP-A-2-183276 JP-A-4-147170 JP 2004-94037 A JP 63-172741 A JP-A-6-145378 Japanese Patent Laid-Open No. 11-109761 Japanese Patent Laid-Open No. 1-1121364 Japanese Utility Model Publication No. 3-063866 JP 7-295391 A Japanese Patent Laid-Open No. 11-109761

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a high-quality image forming apparatus that prevents the occurrence of white spots due to abnormal discharge.

The features of the present invention, which is a means for solving the above problems, are listed below.
The present invention provides a plurality of image carriers, an intermediate transfer member that moves in a predetermined direction and transmits all or a part of light, and a toner image formed on the image carrier to the intermediate transfer member. An image forming apparatus having a plurality of transfer units that sequentially and electrostatically transfer the transfer unit, the transfer unit including a transfer roller that includes an optically anisotropic material in all or part of its thickness direction, and the transfer roller The discharge light detecting means for detecting the discharge light generated at the time of transfer, which is provided on the end side of the light and condensed on the end face by the optically anisotropic material, and the transfer condition of the transfer means according to the information on the detected discharge light An image forming apparatus comprising: a control unit that controls
The present invention is characterized in that the optically anisotropic material is a light-collecting dye.
The present invention is characterized in that the light-collecting dye is a light-collecting fluorescent dye.
The present invention is characterized in that the information related to the discharge light is the light amount, density, or frequency of the detected discharge light.
The present invention is characterized in that a bias applied to the transfer unit or a current value flowing through the transfer unit is changed according to the light amount, density, or frequency of the discharge light.
In the present invention, the discharge light detecting means is formed of a light receiving element, and the light receiving element is composed of a photoelectric conducting element, a photovoltaic element, a photoelectron emitting element, or a composite element thereof, and the transfer element One or more ends are installed at one or both ends of the roller.
In the present invention, a photomultiplier tube or a charge coupled device is used in at least one place as the light receiving device constituting the discharge light detecting means, and the photomultiplier tube or the charge coupled device has a high detection sensitivity. The maximum absorption wavelengths of the light-collecting dyes contained in the transfer roller are combined so as to substantially coincide with each other.
In the present invention, the detection sensitivity of the photomultiplier tube or the charge coupled device has a maximum sensitivity of 400 to 800 nm, and the maximum emission wavelength or maximum absorption wavelength of the fluorescence converted by the dye contained in the transfer roller is , Approximately in the range of 400 to 800 nm.
The present invention is characterized in that at least the resin constituting the intermediate transfer member is obtained by laminating a thermosetting resin in combination with a single layer or another resin.
In the present invention, the resistance control agent is composed of at least an inorganic transparent electronic conductive agent composed of metals or oxides thereof or an ionic conductive agent composed of an organic substance, and at least in an emission wavelength region that can be detected by the discharge light detection means. An intermediate transfer member having a light transmittance of 5% or more is partially used.
The present invention is characterized in that an intermediate transfer member to which a dispersion stabilizer is added is used in order to improve the dispersibility of the resistance control agent in the resin.

  According to the present invention, it is possible to provide a high-quality image forming apparatus by preventing the occurrence of white spots due to abnormal discharge by the means for solving the problems.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

The transfer roller of the present invention requires the electrical resistance and durability required for the conventional roller, but in particular, the discharge light generated in the transfer process has optical anisotropy. It is required that the discharge light can be detected with high sensitivity up to the light detection mechanism at the end of the transfer roller. Therefore, by incorporating a condensing fluorescent dye into the resin constituting the transfer roller, the discharge light generated at the transfer nip is absorbed by the condensing dye in the transfer roller and emitted as fluorescence. The above object can be achieved by a mechanism in which most of the fluorescence in the optically anisotropic layer is guided to the end of the transfer roller while totally reflecting the inside of the layer.
Therefore, as the resin constituting the transfer roller used in the present invention, a known resin can be used as long as it has good transparency. Polyolefin (polyethylene, polypropylene, polynorbornene, etc.), amorphous polyolefin, polyimide, polyamideimide , Polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketone sulfide, polyethersulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, poly Methyl methacrylate, polymethacrylate, polyacrylate, polystyrene, polypropylene, polynorbornene , Cellulose polymer (triacetyl cellulose (TAC), etc.), epoxy resin, phenol resin, norbornene resin, polyester resin, polyethersulfone resin, polysulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, Polynorbornene resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyacrylic resin can be used alone or in combination, or various elastomers and synthetic rubbers such as silicone and urethane can be used. Can be used.

The optically anisotropic material of the present invention is not particularly limited as long as it is an optically anisotropic material. Specifically, it may be used in the thickness direction of the transfer roller so that light can be condensed on the end surface of the transfer roller. The optically anisotropic material is preferably a light-collecting dye, and more preferably a light-collecting fluorescent dye.
The following characteristics are required for the light-collecting fluorescent dye used in the present invention.
(1) High durability: excellent stability against long-time light, heat, electric field, etc. (2) Strong fluorescence: strong tendency to be emitted (3) Chromaticity: Visible range with high sensitivity of detection site (4) Dispersibility: It can be easily dispersed in a resin. The light-collecting fluorescent dye having such characteristics is preferably a cyclic structure dye compound containing an aromatic ring or a heterocyclic ring. Specifically, azo dyes such as azo, bisazo, and trisazo dyes, perylene pigments, azaannulene pigments containing porphyrin rings such as phthalocyanine, flavins, thioflavins, rhodamine B, and the like can be used. Specifically, as listed below, Disperse Yellow 5, Disperse Yellow 54, Disperse Yellow ow56, Disperse Yellow60, Disperse Yellow64, Disperse Yellow160, Disperse Orange13, Disperse Orange30, Solvent Orange5, Solvent Orange45, Reactive Yellow 2, Reactive Orange13, Direct Yellow44, Direct Orange26, Acid Yellow38, Basic Yellow11, Basic Yellow28, Basic Yellow40, Basic Yellow51 , Basic Orange 22, Basic Orange 30, Fluorescent Brightening Agent 54, Fluorescent Br ghtening Agent135, Fluorescent Brightening Agent162, Fluorescent Brightening Agent260, Lumogen F Violet570, Lumogen F Yellow083, Lumogen F Orange240, there is such Lumogen F Red305.
The content of these fluorescent dyes is preferably 1 to 10 wt% with respect to the resin. Moreover, it is preferable that the light emission wavelength also has a maximum value in 400-800 nm where the sensitivity of the said detection member is high.

Suitable examples of the intermediate transfer member of the present invention include a surface layer, a back surface layer, or an intermediate layer, and other structures appropriately selected as necessary.
The shape of the intermediate transfer member is not particularly limited, and can be appropriately selected according to the purpose. Examples thereof include a drum shape (cylindrical shape) and an endless belt shape. Those are preferred.
The structure of the intermediate transfer member is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a single layer structure composed of only the surface layer and a multilayer structure including the surface layer on a substrate. The following ingredients can be used.

  There is no restriction | limiting in particular as a polyimide, According to the objective, it can select suitably, For example, it is obtained by the condensation reaction of aromatic polyhydric carboxylic acid anhydride shown in following Chemical formula 1, its derivative, and aromatic diamine. A rigid polyamic acid containing one or more directly bonded phenyl groups, and a flexible polyamic acid containing two or more phenyl groups that are not directly bonded across another functional group, and Preferred examples include those obtained by reacting at least.

The rigid polyamic acid can be obtained by a condensation reaction represented by the following chemical formula between the aromatic polyvalent carboxylic acid anhydride and an aromatic diamine containing two or more phenyl groups that are directly bonded. Things.
Examples of the flexible polyamic acid include those obtained by a condensation reaction between the aromatic polyvalent carboxylic acid anhydride and an aromatic diamine containing two or more phenyl groups that are not directly bonded with another functional group in between. Can be mentioned.

The aromatic polycarboxylic acid anhydride is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, pyromellitic acid Dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′- Biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4 -Dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3- The Ruboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxylphenyl) -1,1,1,3,3,3 -Hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetra Carboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic acid And tetracarboxylic dianhydrides such as dianhydrides and 1,2,7,8-phenanthrenetetracarboxylic dianhydrides.
These can be used alone or in combination of two or more. The aromatic diamine is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the aromatic diamine containing two or more phenyl groups include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 4,4′-diaminobisphenyl, 3,3′-diaminobisphenyl, and the like. Can be mentioned.

  In addition, aromatic diamines containing two or more phenyl groups that are not directly bonded with other functional groups interposed therebetween include 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, and 3,4′-diaminodiphenyl ether. 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenylmethane, 3,4′- Diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) Sulfide, (3-aminophenyl) (4- Minophenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, bis [4- (3-aminophenoxy) phenyl] methane, Bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] -ethane 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) ) Phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) Phenyl] butane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) ) Phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4- Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, Bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, Bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (3-amino Phenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1, 4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4′-bis [3- (4-aminophenoxy) benzoyl Diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone Bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy] -α, α-dimethylbenzyl] benzene, 1,3- And bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene.

Examples of the aromatic diamine include the aromatic diamine containing two or more phenyl groups directly bonded to each other, and the aromatic containing two or more phenyl groups not bonded directly across another functional group. It is preferable to use one or more diamines after mixing with the aromatic polycarboxylic acid anhydride to form a polyamic acid.
There is no restriction | limiting in particular as mass ratio of the said rigid polyamic acid and the said flexible polyamic acid, Although it can select suitably according to the objective, It is the range of the mixing ratio of 7: 3 to 2: 8. preferable.
Although the polyimide obtained by reacting the rigid polyamic acid has high strength (rigidity), it tends to have brittleness at the same time and may have poor bending resistance.
On the other hand, the polyimide obtained by reacting the bendable polyamic acid is not so high in strength (rigidity), but has an advantage of high bend resistance.
By using a polyimide obtained by reacting the rigid polyamic acid and the flexible polyamic acid as an intermediate transfer member, an intermediate transfer member having high rigidity and high bending resistance can be obtained.

The method for preparing the polyimide is not particularly limited and may be appropriately selected depending on the purpose. For example, the polyamic acid and the other components may be the N-methyl-2-pyrrolidinone, dimethylformamide, dimethylacetamide, It is dissolved in an aprotic polar solvent such as dimethyl sulfoxide, dimethylimidazoline, hexamethylphosphoramide and the like, and then heated and stirred at room temperature at 40 to 80 ° C. to obtain a polyamic acid which is a polyimide precursor.
Next, the polyamic acid is converted into an amide solvent such as NMP (N-methyl-2-pyrrolidinone), DMF (N, N-dimethylformamide), DMAc (N, N-dimethylacetamide), or a polyamic acid such as γ-butyrolactone. It is dissolved in a solvent such as a system solvent, a dipole solvent, ethyl lactate, methoxymethyl propionate, or propylene glycol monomethyl ether acetate to obtain a polyimide-forming varnish having a necessary solid content and viscosity.
There is no restriction | limiting in particular as the addition amount of the said solvent with respect to the said polyamic acid, Although it can select suitably according to the objective, From a viewpoint of the viscosity of a polyimide formation varnish and usability, with respect to 100 mass parts of polyimide formation varnishes. It is preferably 250 to 2000 parts by mass (solid content concentration of about 5 to 30% by mass).
Next, the polyimide-forming varnish is heated and reacted to dehydrate and imidize to prepare the polyimide.
There is no restriction | limiting in particular as heating conditions of the said polyimide formation varnish, Although it can select suitably according to the objective, In order to fully imidize, 100-400 degreeC is preferable and 250-400 degreeC is more. preferable.

Polyamideimide is a resin having a rigid imide group and an amide group imparting flexibility in the molecular skeleton, and a general polyamideimide used in the present invention can be used.
As a method for synthesizing a polyamideimide resin, generally, (1) an isocyanate method to a method for producing a derivative of a trivalent carboxylic acid having an acid anhydride group and an aromatic isocyanate in a solvent (for example, Japanese Patent Publication No. 44-19274). Gazette) (2) Acid chloride method-Derivative halide of a trivalent carboxylic acid having an acid anhydride group, most typically a method of producing a derivative chloride and diamine in a solvent (for example, Japanese Examined Patent Publication No. 42-15637) ) Is used. Each manufacturing method will be described.
(1) Isocyanate method As a derivative of a trivalent carboxylic acid having an acid anhydride group, for example, compounds represented by Chemical Formula 2 and Chemical Formula 3 can be used.

In Chemical Formulas 2 and 3, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or a phenyl group, and Y represents —CH ₂ —, —CO—, —SO ₂ —, or —O—.
Any of these can be used, but most typically trimellitic anhydride is used.
These trivalent carboxylic acid derivatives having an acid anhydride group may be used alone or in combination depending on the purpose.

Next, examples of the aromatic polyisocyanate used in the polyamideimide of the present invention include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 '-[ 2,2-bis (4-phenoxyphenyl) propane] diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-dimethylbiphenyl- 4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'- Diisocyanate 3,3 'Dimethoxy-biphenyl-4,4'-diisocyanate,2,2'-dimethoxy-biphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, it can be used 2,6-diisocyanate. These can be used alone or in combination.
Hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m-xylylene diene as necessary. Aliphatic such as isocyanate and lysine diisocyanate, alicyclic isocyanate and trifunctional or higher polyisocyanate can also be used.
In this method, polyamideimide is produced while generating carbon dioxide gas without passing through polyamic acid. An example using trimellitic anhydride and aromatic isocyanate is shown in Chemical Formula 4.

  In the formula, Ar represents an aromatic group.

(2) Acid chloride method As the derivative halide of a trivalent carboxylic acid having an acid anhydride group, for example, compounds represented by Chemical formula 5 and Chemical formula 6 can be used.

In Chemical Formula 5 and Chemical Formula 6, X represents a halogen element, and Y represents —CH ₂ —, —CO—, —SO ₂ — or —O—.
The halogen element is preferably chloride, and specific examples include terephthalic acid, isophthalic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-biphenyletherdicarboxylic acid, 4,4′-biphenylsulfonedicarboxylic acid, 4,4. '-Benzophenone dicarboxylic acid, pyromellitic acid, trimellitic acid, 3, 3', 4, 4'-benzophenone tetracarboxylic acid, 3, 3 ', 4, 4'-biphenylsulfone tetracarboxylic acid, 3, 3', 4,4'-biphenyltetracarboxylic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, stilbene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, polyvalent carboxylic acid such as 1,2-cyclohexanedicarboxylic acid Of acid chloride.

The diamine is not particularly limited, and any of an aromatic diamine, an aliphatic diamine, and an alicyclic diamine is used, and an aromatic diamine is preferably used.
Aromatic diamines include m-phenylenediamine, p-phenylenediamine, oxydianiline, methylenediamine, hexafluoroisopropylidenediamine, diamino-m-xylylene, diamino-p-xylylene, 1,4-naphthalenediamine, 1, 5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis- (4-aminophenyl) propane, 2,2′-bis- (4-aminophenyl) hexafluoro Propane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl ether, 3,4-diaminobiphenyl, 4,4'-diaminobenzophenone 3,4-diaminodiphenyl ether, iso Propylidenedianiline, 3,3′-diaminobenzophenone, o-tolidine, 2,4-tolylenediamine, 1,3-bis- (3-aminophenoxy) benzene, 1,4-bis- (4-aminophenoxy) ) Benzene, 1,3-bis- (4-aminophenoxy) benzene, 2,2-bis- [4- (4-aminophenoxy) phenyl] propane, bis- [4- (4-aminophenoxy) phenyl] sulfone Bis- [4- (3-aminophenoxy) phenyl] sulfone, 4,4′-bis- (4-aminophenoxy) biphenyl, 2,2′-bis- [4- (4-aminophenoxy) phenyl] Examples include xafluoropropane, 4,4′-diaminodiphenyl sulfide, and 3,3′-diaminodiphenyl sulfide.
Also, siloxane compounds having amino groups at both ends as diamines, such as 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-amino Propyl) polydimethylsiloxane, 1,3-bis (3-aminophenoxymethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-aminophenoxymethyl) polydimethylsiloxane, 1, 3, -bis [2- (3-aminophenoxy) ethyl] -1,1,3,3-tetramethyldisiloxane, α, ω-bis [2- (3-aminophenoxy) ethyl] polydimethylsiloxane, , 3-bis [3- (3-aminophenoxy) propyl] -1,1,3,3-tetramethyldisiloxane, α, ω-bis [3- (3-aminophenoxy) propi [Silicon] If polydimethylsiloxane or the like is used, a silicone-modified polyamideimide can be obtained.

In order to obtain the polyamideimide resin of the present invention by the acid chloride method, the above-described trivalent carboxylic acid derivative halide having an acid anhydride group and diamine are dissolved in an organic polar solvent, as in the production of the polyimide resin. The reaction is carried out at a low temperature (0 to 30 ° C.) to form a polyamic acid (polyamic acid).
Examples of the organic polar solvent used include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide, N, Acetamide solvents such as N-diethylacetamide, pyrrolidinone solvents such as N-methyl-2-pyrrolidinone, N-vinyl-2-pyrrolidinone, phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, Phenol solvents such as catechol, ether solvents such as tetrahydrofuran, dioxane and dioxolane, alcohol solvents such as methanol, ethanol and butanol, cellosolve such as butyl cellosolve or hexamethylphosphoramide, γ Etc. can be mentioned butyrolactone, to use them as sole or mixed solvent desirable. The solvent is not particularly limited as long as it dissolves polyamic acid, but N, N-dimethylacetamide and N-methyl-2-pyrrolidinone are particularly preferable.
Thereafter, the polyamic acid is imidized to form polyamideimide. Examples of the imidization method include a method of dehydrating and ring-closing by heating and a method of chemically ring-closing using a dehydrating and ring-closing catalyst. When dehydrating and ring-closing by heating, the reaction temperature is usually 150 to 400 ° C., preferably 180 to 350 ° C., and the time is usually 30 seconds to 10 hours, preferably 5 minutes to 5 hours. When a dehydration ring closure catalyst is used, the reaction temperature is usually 0 to 180 ° C., preferably 10 to 80 ° C., and the reaction time is several tens of minutes to several days, preferably 2 to 12 hours. Examples of the dehydration ring closure catalyst include acid anhydrides such as acetic acid, propionic acid, butyric acid, and benzoic acid.

The surface layer is not particularly limited as long as it has the above-described electrical characteristics, and can be appropriately selected according to the purpose. However, from the viewpoint of surface characteristics, mechanical characteristics, etc. And those containing other components appropriately selected.
The material for the surface layer is not particularly limited and may be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, Examples thereof include polyester resins, polycarbonate resins, polyethylene resins, fluorine resins, and silicone resins. These may be used individually by 1 type and may use 2 or more types together.
Examples of the amino resin include urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, polyimide resin, polyamideimide resin, and epoxy resin.
Examples of the polyvinyl resin include acrylic resin, polymethyl methacrylate resin, polyacrylonitrile resin, polyvinyl acetate resin, polyvinyl alcohol resin, and polyvinyl butyral resin. Examples of the polystyrene resin include polystyrene resin and styrene acrylic copolymer resin. Examples of the halogenated olefin resin include polyvinyl chloride. Examples of the polyester resin include polyethylene terephthalate resin and polybutylene terephthalate resin. Examples of the fluorine resin include polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride and vinyl fluoride. And fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers.

If necessary, the surface layer may contain a resistance control agent such as conductive powder, which will be described later. However, it is desirable that these conductive powders have no absorption in the visible light region. It is preferable that at least a part of the 500 to 800 nm region having high detection sensitivity has transparency.
For example, after the surface layer is prepared by dissolving the resin in a solvent to prepare a coating solution, the coating solution is uniformly applied to the surface of the polyimide film or the polyamideimide film by a known coating method and dried. It can be formed by baking. Examples of the coating method include known methods such as an immersion method, a spray method, a brush coating method, a roller coating method, a curtain coating method, and a brush coating method.
There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, aromatic solvents, such as benzene, toluene, o-, m-, or p-xylene, acetone, methyl ethyl ketone, methyl Ketone solvents such as isobutyl ketone, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide and N, N-diethyl Acetamide solvents such as acetamide, pyrrolidinone solvents such as N-methyl-2-pyrrolidinone, N-vinyl-2-pyrrolidinone, phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol, etc. Phenolic solvent, tetra Examples include ether solvents such as drofuran, dioxane and dioxolane, alcohol solvents such as methanol, ethanol and butanol, cellosolves such as butyl cellosolve, hexamethylphosphadilamide, and γ-butyrolactone. These may be used alone or as a mixed solvent. It is desirable to use as.

The constituent material of the base layer is blended with an electronic conductive agent in order to keep the surface electrical resistivity within the above-mentioned predetermined range. As the electron conductive agent, carbon black such as ketjen black, furnace black, or acetylene black is generally used, but in the present invention, it is optically transparent in at least a part of the wavelength range in order to detect discharge light. Carbon black cannot be used. Therefore, it is preferable to use an inorganic transparent electronic conductive agent made of at least a metal or its oxide or an ionic conductive agent made of an organic substance.
For example, as the inorganic transparent electronic conductive agent used in the present invention, fine metal powders such as Ni powder, titanium, tin, aluminum, silicon, zinc, zirconia, these metal oxides, ITO (indium tin oxide), ATO (antimony tin oxide) ) And the like, metal salts typified by potassium titanate, barium titanate and the like, or inorganic transparent electronic conductive agents in which a plurality of these are combined are preferable. The blending amount of the inorganic transparent electronic conductive agent depends on the type of the electronic conductive agent and the type of the resin constituting the base layer, but cannot generally be said, but generally about 1 to 50 mass per 100 mass parts of the resin solid content. About 3 parts by weight, more preferably about 3 to 40 parts by weight.
On the other hand, examples of the ionic conductive agent used in the present invention include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), octadecyltrimethylammonium (eg, stearyltrimethylammonium), hexadecyltrimethylammonium, benzyltrimethyl. Perchlorates such as ammonium and modified aliphatic dimethylethylammonium, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate Alkali metal or alkaline earth metal perchlorate such as lithium, sodium, potassium, calcium, magnesium, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, etc. Alkyl sulfates, carboxylates, trifluoromethyl sulfate, sulfonate, and a bis-trifluoromethanesulfonyl imide salt. These may be used alone or in combination of two or more. Moreover, you may use together with the surfactant used as said dispersion stabilizer. The blending amount of the ionic conductive agent depends on the type and the type of resin constituting the base layer, but cannot be generally specified, but is generally about 1 to 70 parts by mass, more preferably about 3 to 100 parts by mass. About 50 parts by mass.
As the resistance control agent, those having high electrical transparency that can obtain predetermined electrical characteristics and that do not hinder the detection of discharge light are suitable, and more important requirements include curing of polyimide resins and polyamideimide resins. Those which do not easily change even at a high temperature of about 200 to 400 ° C. are preferable, for example, organic compounds such as quaternary ammonium base, carboxylic acid group, sulfonic acid group, sulfate ester group, phosphate ester group, or the like Polymers, ether ester amide polymers, ether amide imide polymers, ethylene oxide-epihalohydrin copolymers, compounds having conductive units such as methoxypolyethylene glycol acrylate, or organic antistatic agents such as polymer compounds thereof Can be mentioned. Among these, it is made of a metal oxide such as titanium, tin, alumina, silicon, zinc, zirconia, ITO (indium tin oxide), ATO (antimony tin oxide), etc., and has light transmittance in part or all of the visible light region. The resistance control agent is most desirable because it is stable even at the polyimide curing temperature and can be used without relatively lowering the detection sensitivity.
These metal oxides are themselves surface-treated with a surfactant for the purpose of improving the dispersibility in the resin, or a surfactant is added as a dispersion stabilizer at the same time as the metal oxide. It is still more preferable.

There is no restriction | limiting in particular as said surfactant, According to the objective, it can select suitably, For example, well-known surfactants, such as nonionic property, anionic property, and cationic property, are mentioned.
Examples of the nonionic surfactant include lipophilic oligomers such as long chain alkyl groups, alkene groups, and alkoxy groups, hydrophilic group-containing oligomers such as long chain alkyl groups, alkene groups, and alkoxy groups, and alkylene oxide adducts. It is done.
Examples of the cationic surfactant include alkyl group-containing quaternary ammonium salts.
Examples of the anionic surfactant include sulfonic acids containing long-chain alkyl, alkene, alkoxy, etc., monovalent metal salts and phosphate esters of carboxylic acids.
By being surface-treated with the surfactant, a function as a dispersing agent is also given, the affinity with the polyimide resin or polyamideimide resin is improved, and an intermediate transfer member having a stable transfer current path is obtained. It is done.
There is no restriction | limiting in particular as said organic material, According to the objective, it can select suitably, For example, an alkyd resin, chlorinated polyether, chlorinated polyethylene, an epoxy resin, a fluororesin, a phenol resin, polyamide, polycarbonate, polyethylene Methacrylic resin, polypropylene, polystyrene resin, polyurethane, polyvinyl chloride, polyvinylidene chloride, silicone resin, and the like.
There is no restriction | limiting in particular as said inorganic material, According to the objective, it can select suitably, For example, addition of fillers, such as glass, titanium, silicone, etc. for the purpose of a reinforcement effect, etc. are mentioned.
There is no restriction | limiting in particular as the addition method to the said polyimide of the said other component, According to the objective, it can select suitably, For example, you may melt | dissolve and add to the said polyimide formation varnish. Alternatively, it may be added in the form of fine particles.

  In order to improve the durability of the intermediate transfer member of the present invention, it is possible to improve the intermediate transfer member by sticking a reinforcing member to the end part in order to suppress breakage due to the occurrence of cracks from the end part. As the reinforcing member, an inorganic reinforcing agent such as a metal plate or a ceramic plate or a resin reinforcing member that adheres a plate-like or tape-like resin through an adhesive layer is preferably used. In particular, by covering the end of the intermediate transfer member with known adhesive tapes such as cellulose, vinyl chloride, PTFE, etc., it is possible to maintain simple and good durability.

Method for producing intermediate transfer member The method for producing the intermediate transfer member is not particularly limited and may be appropriately selected depending on the intended purpose. For example, when the intermediate transfer member has a multilayer structure, Examples thereof include a method of forming a surface layer on the material, and a method of obtaining a seamless belt by forming the surface layer into an endless belt when the intermediate transfer member has a single layer structure.
As the method for producing the intermediate transfer member, specifically, a mixed polyamic acid solution containing the rigid polyamic acid and the flexible polyamic acid is applied on a substrate or in a mold, and a coating film forming process is performed. A method of obtaining an intermediate transfer body by heating at least at the same time or after the coating film is formed is preferable.

Method for Producing Single Layer Structure Intermediate Transfer Member A preferred method for producing a single layer structure intermediate transfer member is, for example, a method of forming the polyimide into an endless belt by the following centrifugal molding method or the like.
First, a liquid composition is prepared by dissolving or dispersing the polyimide-forming varnish in a solvent. The type and content of the solvent can be the same as in the case of the multilayer structure intermediate transfer member.
The obtained liquid composition as a belt material is poured into a rotating cylindrical mold, the mold is rotated at a high speed, and the coating liquid is expanded by the centrifugal force to form a uniform film. Form a film.
Next, the liquid composition is heated to a predetermined temperature and imidized to form a polyimide film on the substrate, thereby obtaining an endless belt-shaped intermediate transfer member.
The heating condition can be the same as in the case of the multilayer structure intermediate transfer member.
According to the centrifugal molding method, since the applied liquid composition is expanded by centrifugal force, a polyimide endless belt having a uniform thickness can be obtained.

According to the intermediate transfer member of the present invention, the intermediate transfer member is composed of a material in which the resistance control agent is dispersed in polyimide or polyamideimide. However, the method is not particularly limited, and is appropriately selected using a known disperser or the like. can do. Examples of the disperser include a low speed shear disperser, a high speed shear disperser, a friction disperser, a high pressure jet disperser, and an ultrasonic disperser. Among these, a high-speed shearing disperser is preferable in that the particle size of the dispersion can be controlled to 2 to 20 μm.
When the high-speed shearing disperser is used, conditions such as the rotation speed, dispersion time, and dispersion temperature are not particularly limited and can be appropriately selected according to the purpose. For example, the rotation speed is 1000 -30000 rpm is preferable, 5000-20000 rpm is more preferable, the dispersion time is preferably 0.1-5 minutes in the case of a batch system, and the dispersion temperature is preferably 0-150 ° C. under pressure, -98 degreeC is more preferable. The dispersion temperature is generally easier when the temperature is higher.
In the said dispersion | distribution, 50-2,000 mass parts is preferable with respect to 100 mass parts of raw materials, and 100-1,000 mass parts is more preferable. When the amount used is less than 50 parts by mass, the dispersion state of the raw material is poor and a film having a predetermined dispersion diameter may not be obtained. When the amount exceeds 2,000 parts by mass, the production cost increases. There is. If necessary, a dispersant is preferably used from the viewpoint of sharpening the particle size distribution and stably dispersing.

There is no restriction | limiting in particular as said dispersing agent, According to the objective, it can select suitably, For example, surfactant, a poorly water-soluble inorganic compound dispersing agent, a polymeric protective colloid, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, surfactants are preferable.
Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.
Examples of the anionic surfactant include alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters and the like, and those having a fluoroalkyl group are preferable. Examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms or a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 3- [omega-fluoroalkyl (6 carbon atoms). -11) Oxy] -1-alkyl (carbon number 3-4) sodium sulfonate, 3- [omega-fluoroalkanoyl (carbon number 6-8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (Carbon number 11-20) carboxylic acid or its metal salt, perfluoroalkyl carboxylic acid (carbon number 7-13) or its metal salt, perfluoroalkyl (carbon number 4-12) sulfonic acid or its metal salt, perfluoro Octanesulfonic acid diethanolamide, N-propyl-N- (2-hydro Ciethyl) perfluorooctanesulfonamide, perfluoroalkyl (carbon number 6-10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (carbon number 6-10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (carbon number) 6-16) Ethyl phosphate and the like. Commercially available surfactants having a fluoroalkyl group include, for example, Surflon S-111, S-112, S-113 (manufactured by Asahi Glass Co., Ltd.); Fluorard FC-93, FC-95, FC-98, FC- 129 (manufactured by Sumitomo 3M); Unidyne DS-101, DS-102 (manufactured by Daikin Industries); Megafac F-110, F-120, F-113, F-191, F-812, F-833 (large) Nihon Ink Co., Ltd.); Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products); Manufactured) and the like.

Examples of the cationic surfactant include amine salt type surfactants and quaternary ammonium salt type cationic surfactants. Examples of the amine salt type surfactant include alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazolines, and the like. Examples of the quaternary ammonium salt type cationic surfactant include alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride and the like. . Among the cationic surfactants, aliphatic quaternary ammonium such as aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, and perfluoroalkyl (6 to 10 carbon atoms) sulfonamidopropyltrimethylammonium salt. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Commercially available products of the cationic surfactant include, for example, Surflon S-121 (manufactured by Asahi Glass Co., Ltd.); Florard FC-135 (manufactured by Sumitomo 3M); F-824 (manufactured by Dainippon Ink, Inc.); Xtop EF-132 (manufactured by Tochem Products);
Examples of the nonionic surfactant include fatty acid amide derivatives and polyhydric alcohol derivatives.
Examples of the amphoteric surfactant include alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine, N-alkyl-N, N-dimethylammonium betaine and the like.

Examples of the poorly water-soluble inorganic compound dispersant include tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite.
Examples of the polymeric protective colloid include acids, (meth) acrylic monomers containing a hydroxyl group, vinyl alcohol or ethers of vinyl alcohol, esters of vinyl alcohol and a compound containing a carboxyl group, amides Examples thereof include homopolymers or copolymers such as compounds or their methylol compounds, chlorides, those having a nitrogen atom or a heterocyclic ring thereof, polyoxyethylenes, and celluloses.
Examples of the acids include acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and the like. Examples of the (meth) acrylic monomer containing a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, and γ-acrylate. -Hydroxypropyl, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, Examples include glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide and the like. Examples of the vinyl alcohol or ethers with vinyl alcohol include vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, and the like. Examples of the esters of vinyl alcohol and a compound containing a carboxyl group include vinyl acetate, vinyl propionate, and vinyl butyrate. Examples of the amide compound or these methylol compounds include acrylamide, methacrylamide, diacetone acrylamide acid, or these methylol compounds. Examples of the chlorides include acrylic acid chloride and methacrylic acid chloride. Examples of the homopolymer or copolymer such as those having a nitrogen atom or a heterocyclic ring thereof include vinyl pyridine, vinyl pyrrolidinone, vinyl imidazole, and ethylene imine. Examples of the polyoxyethylene are polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene Examples thereof include oxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, and polyoxyethylene nonyl phenyl ester. Examples of the celluloses include methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.
As the drying step, a known method can be used as long as it reaches the curing temperature (200 to 400 ° C.) of the polyimide resin or polyamideimide resin, and an external heating method or an internal heating method can be used. For example, a method using a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace or the like, a method of radiating and heating a high temperature gas such as a dryer, a method using a microwave, or the like can be given.

  The surface linear velocity at the time of image formation of the intermediate transfer member is generally one that is driven in the range of 80 to 400 mm / s, which is also preferable in the present invention. The reason for this is that when used in the above speed range, the transfer electric field becomes dull and distorted, resulting in an increase in abnormal images such as transfer dust, and at low speeds below the speed range, discharge tends to occur and image deterioration due to discharge occurs. This is because the problem that it becomes easy and cannot be handled at high speed is exposed.

FIG. 1 shows an apparatus configuration example for detecting discharge light in the present invention.
In the sheet member discharge detection device of the present invention, a sample sheet 1 cut out from a transfer belt or the like to be observed is placed on an electrode 2 and a voltage is applied to the electrode 2 from the outside to short-circuit the sample sheet 1 and ground. A video camera incorporating a CCD with a discharge light generated between the ITO (Indium-Tin-Oxide) electrode 7 introduced into an image intensifier 4 via a mirror 5 and a multiplied discharge image. 3 and so on. In this device, in order to capture minute light emission, two image intensifiers 4 (V1366P made by Hamamatsu Photonics) are arranged in series, and an image is formed on the entrance side of each image intensifier. A lens 9 (manufactured by PENTAX, smc PENTAX-A DENTAL MACRO 1: 4 100 mm) and a lens 10 (manufactured by PENTAX, smc PENTAX-FA 1: 2.8 50 mm MACRO) are disposed. The distance between the sample sheet 1 and the transparent electrode 7 is controlled on the order of 1 μm by moving the stage 8 using the stepping motor 12, and the stepping motor 12 is a stepping motor controller 13 (stepping motor controller manufactured by Suruga Seiki Co., Ltd.). D70) is controlled by the personal computer 14. The bias applied to the electrode 2 is also controlled by the personal computer 14 via the amplifier 11 (manufactured by Trek, MODEL 677A).

In this device, image intensifiers with a maximum luminance gain of 6 × 10 ⁴ [ft-L / ft-c] are arranged in series, and a luminance gain exceeding 3 × 10 ⁹ is obtained by calculation, thereby obtaining a sample on the sample sheet. We succeeded in visualizing even minute discharge unevenness. As a matter of course, any image intensifier can be used as long as it has a performance equal to or higher than this, and moreover, when observing rough discharge unevenness, It is also possible to use a low luminance gain. In such a case, it is possible to observe only one image without arranging a plurality of image intensifiers. However, a luminance gain of at least 1 × 10 ⁴ [ft−L / ft−c] is required. It is desirable to use an image intensifier with.

FIG. 2 is a schematic diagram of a result of observing discharge unevenness of the transfer belt samples A, B, and C using the discharge light observation device for the sheet member of this example. Samples A and B are polyimide belts in which conductive carbon is dispersed, and C is an ion conductive PVDF (polyvinylidene difluoride) belt. And observed. As shown in the figure, it can be seen that by using the discharge light observation apparatus of the present embodiment, it is possible to clearly confirm the discharge unevenness and the difference in the electric field dependency of the generation tendency thereof.
It should be noted that in the case where there is a region having a high resistance in the sample sheet or a layer having a high resistance on the back surface layer of the sheet and a continuous discharge does not occur with a DC bias, the electrode 2 By continuously generating a discharge by superimposing an AC bias having a large amplitude, it becomes possible to see the tendency of discharge unevenness. Therefore, it is very effective to use an AC bias when observing discharge unevenness. When observing discharge unevenness, it is desirable to measure the offset value of the DC bias component, the amplitude and frequency of the AC component under various conditions.

On the other hand, it is necessary to establish an image quality control technique based on the detection of the discharge light, and the discharge light in the transfer process in the image forming apparatus with a small light receiving element is used without using the large discharge light detection means as shown in FIG. It is necessary to detect the occurrence state and control the process conditions on the apparatus side so as not to generate a blank image.
In contrast to this, the present inventors adopt the above intermediate transfer member having optical transparency, and detect the discharge occurrence state by providing a discharge light receiving element in the transfer process or in the vicinity thereof, and as a result, Based on the above, the image forming apparatus is provided with a mechanism for performing process control in order to maintain the image quality, and the present invention has been achieved.
Examples of the discharge light detecting means used in the present invention include the following light receiving elements, specifically, photoelectric conducting elements composed of Cd—S cells, Cd—Se cells, PbS sensors, etc., Si, Ge, GaP, Photovoltaic elements such as PN-type diodes, PIN-type diodes, Schottky diodes, avalanche diodes represented by GaAsP, InGaAsP / InP, and the like, and phototransistor elements, photo ICs, phototriac elements, and photothyristor elements using them Alternatively, a photoelectric imaging tube, a photoelectron emission type device called a photomultiplier tube, a photodiode array or a PSD (Position Sensitive Detector), a CCD image sensor, a MOS image sensor or the like as a composite type of these devices can be suitably used. .

In the present invention, at least one of the light receiving elements is installed, a discharge light generation state in the transfer process is detected by the light receiving element, and a state in which a strong discharge is observed locally generates a blank image. Therefore, it is possible to form a high-definition image without white spots by controlling the process conditions such as reducing the transfer bias to a condition where the discharge light intensity detected by the light receiving element is not locally concentrated. is there. Therefore, the light receiving elements used in the present invention are, for example, two or more locations on the rotation axis of the intermediate transfer member, and a mechanism for detecting the difference in the amount of discharge light observed at each portion. Further, in some photodiodes, there is a technique in which the light receiving unit is divided into two or four or more and the deviation of the irradiated light is detected by the light amount difference between the divided surfaces. The present invention is used for this. In this case, if the light receiving element is provided at one or more places, the function can be achieved, and the cost can be reduced.
In addition, the light receiving element used in the present invention can detect the density or frequency difference of the discharge light observed at each part. Specifically, it is possible to detect a difference in the light reception frequency of the light flux and the discharge light.

  In the present invention, the bias applied to the transfer unit or the value of the current flowing through the transfer unit can be changed according to the light quantity, density, or frequency of the discharge light. As a result, it is possible to detect the distribution state of the discharge generated by the application of the transfer electric field, feed back the transfer process conditions, and prevent the occurrence of white spots and abnormal images due to density unevenness.

  The image forming apparatus according to the present invention includes an image carrier that can form a latent image on which a toner image can be carried, a developing unit that develops the latent image formed on the image carrier with toner, and a developing unit that develops the latent image. An intermediate transfer body on which the toner image formed is primarily transferred, a transfer means for secondary transfer of the toner image carried on the intermediate transfer body to a transfer material, and other means appropriately selected as necessary, for example, , An intermediate transfer type image forming apparatus having a charge eliminating unit, a cleaning unit, a control unit, and the like.

Further, the image forming method in the image forming apparatus of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and further other steps appropriately selected as necessary. For example, a static elimination process, a cleaning process, a recycling process, a control process, and the like are included.
The image forming method can be suitably performed by the image forming apparatus, the electrostatic latent image forming step can be performed by the electrostatic latent image forming unit, and the developing step is performed by the developing unit. The transfer step can be performed by the transfer unit, the fixing step can be performed by the fixing unit, and the other steps can be performed by the other unit.

Electrostatic latent image forming step and electrostatic latent image forming means The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image carrier.
The material, shape, structure, size, etc. of the electrostatic latent image carrier (or photoconductor) is not particularly limited, and can be appropriately selected from known ones. The material is preferably an inorganic photoreceptor such as amorphous silicon or selenium, or an organic photoreceptor such as polysilane or phthalopolymethine. Among these, amorphous silicon inorganic photoreceptors and organic photoreceptors using phthalocyanine-based polymethine pigments are preferably used from the viewpoint of long life.
The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then performing imagewise exposure, and is performed by the electrostatic latent image forming unit. be able to.
The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise. Prepare.
The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The exposure can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure device.
The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger so as to form an image to be formed, and is appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system can be used.
In addition, you may employ | adopt the back light system which exposes imagewise from the back surface side of the said electrostatic latent image carrier.

Developing Step and Developing Unit The developing step is a step of developing the electrostatic latent image using the developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the developer, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, the developer, and can be appropriately selected from known ones. For example, the developer is accommodated and the electrostatic latent is stored. Preferable examples include those having at least a developing unit capable of applying the developer to the image in a contact or non-contact manner.
The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multicolor developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.
In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier (photoconductor), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted. It moves to the surface of the electrostatic latent image carrier (photoconductor) by force. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier (photoconductor).
The developer accommodated in the developing device is the developer, but the developer may be a one-component developer or a two-component developer.

The transfer step is a step of transferring the visible image to a recording medium. An intermediate transfer member is used to primarily transfer the visible image onto the intermediate transfer member, and then the visible image is transferred onto the recording medium. A secondary transfer mode is preferable, and a primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer member using two or more colors, preferably a full color toner as the toner, and the composite A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the latent electrostatic image bearing member (photoconductor) of the visible image using a transfer charger, and can be performed by the transfer unit. The transfer unit includes a primary transfer unit that transfers a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. Embodiments are preferred.
The shape of the intermediate transfer member is not particularly limited, and can be appropriately selected from known transfer members according to the purpose. For example, a transfer belt or a transfer drum is preferable.
The transfer means (the primary transfer means and the secondary transfer means) is a transfer device that peels and charges the toner image formed on the electrostatic latent image carrier (photoconductor) to the recording medium side. It is preferable to have at least. There may be one transfer means or two or more transfer means.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrostatic latent image carrier. Preferably mentioned.
The cleaning step is a step of removing the electrophotographic toner remaining on the electrostatic latent image carrier, and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Preferred examples include brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.
The control means is a process for controlling the steps, and can be suitably performed by the control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.
The specific structure of the image forming apparatus is not particularly limited as long as it has the above structure, and can be appropriately selected according to the purpose. The image forming apparatus is preferably mentioned.

FIG. 3 is a block diagram showing an image forming apparatus according to the first structure of the present invention.
Spherical images formed on the respective photosensitive drums 101a to 101d by the photosensitive drums 101a to 101d, the non-contact charging rollers 103a to 103d, the developing devices 104a to 104d, the primary transfer rollers 105a to 105d, and four exposure devices (not shown). A primary transfer image forming unit A101 to A104 that primarily transfers a toner image made of polymerized toner onto the intermediate transfer belt 106 and forms a primary transfer image on the intermediate transfer belt 106, and the intermediate transfer belt 106. The primary transfer image is transferred to a transfer material (not shown) to form a transfer electric field for obtaining a secondary transfer image, a secondary transfer roller 107, a conveying belt 108, a counter roller 109, and a secondary on the transfer material. Fixing roller 110 and pressure roller 111 for fixing the transferred image, heating roller 114 having a heater, fixing belt 11 , And a cooling fan 113.
In this apparatus, when color image data is generated by a scanner or the like, in the primary transfer image forming unit A101, the non-contact charging roller 103a biased negatively first uniformly charges the photosensitive drum 101a and then is not shown. The exposure device forms an electrostatic latent image on the surface of the photosensitive drum 101a. Subsequently, the developing device 104a reversely develops toner having a negative charge, whereby a toner image is formed on the photoreceptor 101a. A positive bias having a polarity opposite to the polarity of the toner is applied to the primary transfer transfer roller 105a, and the toner image on the photosensitive drum 101a is generated by a transfer electric field formed with the primary transfer roller 105a. The image is transferred onto the intermediate transfer belt 106 to form a primary transfer image. Similarly, in the primary transfer image forming units A102 to A104, image formation is performed at each timing, and a primary transfer image composed of four colors of toner is formed on the intermediate transfer belt 106.

Subsequently, the material to be transferred is conveyed from the paper feed tray 112 to the secondary transfer nip portion formed by the opposing roller 109 and the secondary transfer roller 107 at the timing when the primary transfer image is formed. The opposite roller 109 is applied with a bias having the same polarity as the toner, and the toner image is transferred to the transfer material by the electric field formed between the opposite roller 109 and the secondary transfer roller 107, and the secondary transfer. An image is formed. Next, the transfer material is introduced into a fixing nip formed by the fixing roller 110 and the pressure roller 111 to fix the toner, and is sent to a paper discharge tray (not shown) as a final image.
The discharge light detection function of the present invention can be applied to either the primary transfer roller or the secondary transfer roller, and may be provided in both. When applied to the primary transfer rollers 105a, 105b, 105c, and 105d, the intermediate transfer belt 106 is also transparent to at least a part of the wavelength range of the discharge light, and adjusts the transfer electric field while detecting the discharge light to It is possible to form an image without missing. It can also be applied to the secondary transfer roller 107 or 109. In the case of 109, it can be used under the same conditions as the primary transfer roller. However, when detecting from the secondary transfer roller 107, it passes over a transfer body such as paper. Since it cannot be detected, it can be applied by adjusting the detection timing such as a paper interval.

FIG. 4 is a block diagram showing an image forming apparatus according to the second structure of the present invention.
The image forming apparatus shown in the figure includes a photosensitive belt 201 as an electrostatic latent image carrier, and a black developing unit K, a cyan developing unit C, a magenta developing unit M, which are arranged around the photosensitive belt 201. A developing means having a yellow developing unit Y, an intermediate transfer drum 208 abutted on the photosensitive belt 201 with a predetermined nip portion, and the photosensitive belt 201 and the intermediate transfer drum 208 with respect to the intermediate transfer drum 208 The primary transfer roller 203 in contact with the nip portion, the secondary transfer roller 204 in contact with the intermediate transfer drum 208 on the downstream side in the rotation direction of the intermediate transfer drum 208, and the transfer material 205 being conveyed more than the secondary transfer roller 204 The sheet neutralizing unit 206 disposed on the downstream side in the direction and the cleaning unit 207 disposed opposite to the intermediate transfer drum 208. It is equipped with a. In this configuration, the intermediate transfer drum 208 is a multi-layer intermediate transfer body having a surface layer on a cylindrical drum base material. In the present invention, the primary transfer roller 202 or the intermediate transfer body 208 is optically coupled. It has an anisotropic layer and a discharge light detection unit 203 is arranged at the end thereof.
In the image forming apparatus according to the structure shown in FIG. 4, the toner image T developed on the photosensitive belt 201 by the appropriately selected one of the developing units Y, M, C, and K is combined with the photosensitive belt 201. A predetermined bias potential is applied via a primary transfer roller 203 at a primary transfer portion which is a nip portion with respect to the intermediate transfer drum 208, and the intermediate transfer drum 208 is synchronously rotated with respect to the photosensitive belt 201. Transcribed.
The toner images of the respective colors (black, yellow, magenta, cyan) developed by the developing units Y, M, C, and K are sequentially transferred onto the intermediate transfer drum 208, and the color toner image is transferred onto the intermediate transfer drum 208. Is superimposed.

The secondary transfer roller 204 may be equipped with a contact / separation mechanism that moves away from the intermediate transfer drum 208 during non-transfer, and is moved so as to contact the intermediate transfer drum 208 during secondary transfer described below. .
The transfer material 205 conveyed in synchronization with the rotation of the intermediate transfer drum 208 passes between the intermediate transfer drum 208 and the secondary transfer roller 204. At this time, a bias voltage having a polarity opposite to the charging polarity of the toner image is applied to the secondary transfer roller 204. The color toner image primarily transferred onto the intermediate transfer drum 208 is secondarily transferred onto a transfer material 205 that passes between the intermediate transfer drum 208 and the secondary transfer roller 204. In this configuration, the photoconductor belt 201 is shared, but a photoconductor having a belt or drum configuration may be provided for each color toner, and this may be configured to sequentially perform primary transfer to the intermediate transfer drum.
Thereafter, the transfer material 205 is given a predetermined charge by the sheet discharging means 206 and the staying charge is removed. Thereafter, the transfer material 205 is conveyed to a fixing unit (not shown) and moves to a fixing step.
On the other hand, the transfer residual toner remaining on the intermediate transfer drum 208 is removed by a cleaning unit 207 (brush, roller, etc.) arranged to face the intermediate transfer drum 208. Thereafter, the intermediate transfer drum 208 is initialized by being neutralized by a neutralizing unit (not shown).

  FIG. 5 is a view showing a discharge detecting means at the end of the transfer roller. The minute discharge light generated during the primary transfer is condensed on the end surface of the transfer roller 105 by the optical anisotropic layer 116 of the transfer roller 105. The condensed light is received by the light receiving device 118 through the photomultiplier 117. This makes it possible to detect a slight amount of discharge light generated by applying a transfer electric field, feed back the transfer process conditions, and prevent the occurrence of blank images and abnormal images due to density unevenness.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited only to the following Example.
(Example 1)
Production of Transfer Roller Having Optically Anisotropic Layer The transfer roller used in the present invention is a polymethyl methacrylate resin (Sekisui Chemical's S-LEC Co., Ltd.) for the primary transfer roller used in Ricoh color copier Imagio Neo C600 E) Using a solution obtained by dissolving 100 parts and 5 parts of a condensing fluorescent dye (Lumogen F Red305 manufactured by BASF) in toluene, the roller is provided with a 3 mm fluorescent dye-containing polymethyl methacrylate resin film on its surface by dip coating. A transfer roller having the optically anisotropic layer was obtained.

Preparation of Varnish for Forming Intermediate Transfer Member Rigid polyimide forming varnish represented by the following chemical formula 7 obtained by dissolving rigid polyamic acid in NMP (N-methyl-2-pyrrolidinone) as an appropriate amount of amide solvent: U Flexibility represented by the following chemical formula 8 formed by dissolving varnish S (trade name: manufactured by Ube Industries) and flexible polyamic acid in NMP (N-methyl-2-pyrrolidinone) which is an appropriate amount of an amide solvent. Polyimide-forming varnish: U varnish A (trade name: manufactured by Ube Industries) was mixed at a weight ratio such that rigid polyimide-forming varnish: flexible polyimide-forming varnish was 5: 5 to obtain a mixed varnish. .

  As a resistance control agent, ITO (Indium Tin Oxide) is surface-treated with a reagent grade hexamethyldisilazane made in advance by Kanto Chemical Co., Ltd., then heat-treated at 120 ° C., and 30 parts by mass of a master batch solution dispersed in a mass ratio is mixed. A varnish for forming an intermediate transfer member was prepared by mixing the varnish at 8: 2.

The seamless belt-like intermediate transfer member of the present invention was produced by the following method.
FIG. 6 is a view showing a centrifugal molding apparatus. In FIG. 6, the rotating shaft of the centrifugal molding device 42 having the cylindrical molding die 43 is disposed in the horizontal direction, and the molding die 43 is rotated at a high speed of 500 rpm, so that the entire surface of the cavity 44 in the molding die 43 is provided. A release liquid was applied to form a release liquid film layer having a uniform thickness of about 50 μm.
Next, the rotational speed of the molding die 43 is reduced to 100 rpm, and the intermediate transfer member forming varnish as the belt material liquid is ejected from the nozzle 46 of the spray 45 inserted into the cavity, so that the entire surface of the cavity 44 is ejected. The intermediate transfer member forming varnish was applied.
Thereafter, the number of rotations of the mold 43 was increased to 500 rpm, the coating liquid film of the intermediate transfer member forming varnish was made uniform, and a belt material layer was formed.
Furthermore, about 100 ° C. dry air was introduced into the cavity 44 from the spray 45 side to dry the belt material layer.
Next, the belt material layer is taken out from the molding die 43, the belt material layer is placed in another molding die, heated at about 120 ° C. for 20 minutes, solvent drying, and preliminarily imide. Made.
Further, the belt material layer was imidized by heating at 320 ° C. for 120 minutes to produce a transparent and smooth seamless intermediate transfer belt used in Example 1.
When the film thickness of the obtained intermediate transfer belt of Example 1 was determined using a micrometer manufactured by Mitutoyo Corporation, it was 80 ± 2 μm.

<Evaluation of discharge area>
Discharge Light Observation Device Using the “discharge light observation device” shown in FIG. 1, the discharge light on the transfer belt surface was observed when a vertical electric field less than the dielectric breakdown electric field was applied to the transfer belt.
Evaluation of Discharge Area FIG. 2 is a schematic diagram in which discharge light observed when various belt samples are observed using the “discharge light observation apparatus” is classified into three types.
Pattern A in FIG. 2 represents the case where a plurality of local strong discharge lights are observed simultaneously in the observation region, and the island-like region where the local strong discharge light is observed does not change over time. Represents a case where weak discharge light is formed in an island shape in the observation region, and a region where local strong discharge light is observed blinks at random at the same time, and pattern C is in the observation region. In this case, weak discharge light is observed uniformly.
A transfer belt, as shown by types A and B in FIG. 2, having a plurality of island-like regions where a strong local discharge light is observed simultaneously on the belt surface in an electric field less than the breakdown electric field of the belt. When the image forming apparatus is mounted on an image forming apparatus, non-uniform discharge concentrated locally before and after the transfer nip occurs during transfer, and it has been confirmed that density unevenness and white spots appear on the output image. As a result of further investigation, local strong discharge light is generated in an observation region having an area of at least 1 cm ^{2 in} area, and a plurality of island-like islands as shown in FIGS. 2A and 2B are simultaneously observed. In such an intermediate transfer body, it was confirmed that uneven density and white spots are likely to occur on the output image.

Therefore, the state where strong discharge light was observed locally was reproduced with an actual machine, and the following image evaluation was performed.
<Image quality evaluation>
Using the Ricoh color copier Imagio Neo C600 remodeled machine, the above intermediate transfer belt was further mounted, and the image on the transfer belt was evaluated. The Imagio Neo C600 remodeling machine uses a two-component development system for development and an intermediate transfer belt system for transfer, and the image forming operation can be stopped halfway at an arbitrary timing by an external signal. Write a plurality of solid images and latent images of fine line images on the photosensitive drum, stop the image forming process during the primary transfer, take out the photosensitive drum unit and the transfer belt unit from the copying machine, and print a solid image portion on the photosensitive drum. The pile height was measured, and the image of the fine line portion on the transfer belt was evaluated. The toner mass M / A per unit area was set to about 0.6 mg / cm ² . Further, the surface linear velocity of each member including the transfer belt and the photosensitive member of the modified machine is 250 mm / s.

<Outline image evaluation method>
A 2 × 2 dot pattern was formed using the intermediate transfer member of the above-mentioned Imagio Neo C600 remodeling machine, and the image state on the intermediate transfer belt was observed with an ultra-deep shape measuring microscope (VK8500; manufactured by Keyence). After editing this image into a binarized image using image analysis software (ImagePro from MediaCybernetics), the area of the solid pattern where the toner is missing and the white area is quantified, and the blank image in the entire area is The rank was evaluated as follows.

<< White rank >>
3 Good, white area ratio <1%
2 Within tolerance, white area ratio <4%
1 Problem, white area ratio ≧ 4%
However, the allowable range of the white area ratio is 4% or less.
The white spot rank in this example is 1, and it was confirmed that a white spot image was generated even in the actual machine when local strong discharge light as shown by types A and B in FIG. 2 was observed. .

(Example 2)
In order to actually detect the discharge light, first, a Hamamatsu Photonics quadruple SiPIN photodiode array S5981 type is used as a light receiving element on the end face immediately below the transfer nip of the primary transfer roller 5a in FIG. A light guide was brought into contact with the end face of the roller, and the light quantity fluctuation was measured. However, since the discharge light itself is a transient phenomenon in the measurement at one point, there are too many errors only by the variation, and detection and control are difficult. Therefore, the light guide was brought into contact with both end faces of the primary transfer roller 5a, and after confirming that the maximum difference value of the detected photocurrent did not exceed 5 μA, the transfer current was confirmed to be 19 μA. When the 2 × 2 dot pattern image was output under the same conditions, the blank spot rank was 3, and it was confirmed that a very good image was output.

(Example 3)
In Example 2, the transfer current was confirmed to be 29 μA after confirming that the maximum difference value of the detected photocurrent exceeded 5 μA by increasing the transfer current. When the 2 × 2 dot pattern image was output under the same conditions, the white spot rank was 1, and it was confirmed that a white spot image was generated.

Example 4
In the second embodiment, three light guides connected to the four-part SiPIN photodiode array S5981 manufactured by Hamamatsu Photonics Co., Ltd. as the light receiving element are installed on one end face of the primary transfer roller 5a in FIG. The presence or absence of discharge light was confirmed in the same manner as in 1. It was confirmed that the difference value of each divided portion of the detection unit exceeded 5 μA at the maximum, and the transfer current was confirmed to be 27 μA. In the same manner as in the first embodiment, when the 2 × 2 dot pattern image is output, a blank image is generated in the visualized portion. Therefore, the evaluation based on the blank image evaluation method was performed. It was confirmed that the blank spot rank was 1.

(Example 5)
The transfer current in Example 4 was slightly lowered, and the presence or absence of discharge light was confirmed in the same manner as in Example 1. It was confirmed that the difference value of each divided part of the detection part did not exceed 5 μA at the maximum, and the transfer current was confirmed to be 19 μA. In the same manner as in the first embodiment, when the 2 × 2 dot pattern image is output, a blank image is generated in the visualized portion. Therefore, the evaluation based on the blank image evaluation method was performed. It was confirmed that the blank spot rank was 1.

  From the above results, it is possible to detect the discharge state of the transfer NIP portion by performing the discharge light detection of the present invention, and to suppress the occurrence of a blank image by performing the process condition control as described above. However, the image quality of the image forming apparatus was maintained at a high level.

It is the schematic which shows the apparatus which detects the discharge light of a sheet | seat member. It is a figure explaining the correlation with a blank image from the discharge light observation image image | photographed using the apparatus which detects discharge light. 1 is a configuration diagram illustrating an image forming apparatus according to a first structure of the present invention. It is a block diagram which shows the image forming apparatus which concerns on the 2nd structure of this invention. FIG. 4 is a diagram illustrating a discharge detection unit at an end portion of a transfer roller. It is a figure which shows a centrifugal molding apparatus. It is a figure which shows the method of measuring surface resistance with three contact terminals.

Explanation of symbols

1 Sample sheet 2 Electrode 3 CCD
4 Image Intensifier 5 Mirror 6 ITO Electrode Fixing Stand 7 ITO Electrode 8 Electrode Stage 9 Condensing Lens 10 Imaging Lens 11 Amplifier 12 Stepping Motor 13 Stepping Motor Controller 14 Control PC
42 Centrifugal forming device 43 Mold 44 Cavity 45 Spray 46 Nozzle 47 Dry air flow 101a to 101d Photosensitive drums 103a to 103d Charge rollers 104a to 104d Developers 105a to 105d Primary transfer roller 106 Intermediate transfer belt 107 Secondary transfer roller 108 Conveying belt 109 Opposing roller 110 Fixing roller 111 Pressure roller 112 Paper feed tray 113 Air cooling fan 114 Heating roller 115 Fixing belt 116 Optical anisotropic layer 117 Photomultiplier 118 Light receiving device 119 Discharge light detecting device 201 Photosensitive belt K Black development unit 202 Primary transfer roller C Cyan development unit 203 Discharge light detection unit M Magenta development unit 204 Secondary transfer roller Y Yellow development unit 205 Transfer material (paper, etc.)
206 Sheet neutralizing means 207 Cleaning means 208 Intermediate transfer drums 301a, 301b, 301c Contact terminal 302 Substrate 303 Internal wiring 304a, 304b Wiring portion to measuring instrument

Claims (11)

A plurality of image carriers;
An intermediate transfer member that moves in a predetermined direction and transmits all or part of the light;
A plurality of transfer means for electrostatically sequentially transferring the toner image formed on the image carrier to the intermediate transfer body;
In an image forming apparatus having
The image forming apparatus includes:
The transfer means has a transfer roller containing the optically anisotropic material in all or part of its thickness direction,
Discharge light detecting means provided on the end side of the transfer roller and detecting discharge light generated during transfer, which is condensed on the end face by the optically anisotropic material,
Control means for controlling the transfer conditions of the transfer means according to information on the detected discharge light;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
The image forming apparatus includes:
An image forming apparatus, wherein the optically anisotropic material is a light-collecting dye. The image forming apparatus according to claim 2.
The image forming apparatus includes:
An image forming apparatus, wherein the light condensing dye is a light condensing fluorescent dye. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus includes:
An image forming apparatus characterized in that the information relating to the discharge light is the amount, density, or frequency of the detected discharge light. The image forming apparatus according to claim 4.
The image forming apparatus includes:
An image forming apparatus, wherein a bias applied to the transfer unit or a current value flowing through the transfer unit is changed according to a light amount, density, or frequency of the discharge light. The image forming apparatus according to any one of claims 1 to 5,
The image forming apparatus includes:
The discharge light detecting means is formed of a light receiving element;
The light receiving element is
It is composed of a photoconductive element, a photovoltaic element, a photoelectron emitting element, or a composite element thereof.
One or more image forming apparatuses are provided at one or both ends of the transfer roller. The image forming apparatus according to claim 6.
The image forming apparatus includes:
A photomultiplier tube or a charge coupled device is used in at least one place as the light receiving element constituting the discharge light detecting means,
An image forming apparatus, wherein the photomultiplier tube or the charge coupled device is combined in a region where the detection sensitivity is high so that the maximum absorption wavelength of the condensing dye contained in the transfer roller is substantially the same. The image forming apparatus according to claim 7.
The image forming apparatus includes:
The detection sensitivity of the photomultiplier tube or charge-coupled device has a maximum sensitivity at 400 to 800 nm,
An image forming apparatus characterized in that the maximum emission wavelength or maximum absorption wavelength of fluorescence converted by the dye contained in the transfer roller substantially matches the range of 400 to 800 nm. The image forming apparatus according to claim 1,
The image forming apparatus includes:
An image forming apparatus, wherein at least the resin constituting the intermediate transfer member is a laminate of a thermosetting resin combined with a single layer or another resin. The image forming apparatus according to any one of claims 1 to 9,
The image forming apparatus includes:
The resistance control agent is composed of at least an inorganic transparent electronic conductive agent made of metals or oxides thereof or an ionic conductive agent made of organic matter,
An image forming apparatus comprising an intermediate transfer member having a light transmittance of 5% or more in at least a part of a light emission wavelength region detectable by the discharge light detecting means. The image forming apparatus according to claim 1,
The image forming apparatus includes:
An image forming apparatus using an intermediate transfer member to which a dispersion stabilizer is added in order to improve dispersibility of the resistance control agent in the resin.

Images