JP2003091165A - Semiconductive endless belt and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive endless belt which is used for tandem type, intermediate transfer type and tandem intermediate transfer type image forming apparatuses and whose variance of resistance is restrained to be small, and an image forming device to which the semiconductive endless belt is attached. SOLUTION: This semiconductive endless belt whose variance of the resistance is restrained to be small and which has the stable resistance is manufactured by using a conductive agent obtained by coating resin having high charge attenuable property as a conductive agent to be added to a resin layer constituting the belt in the case of manufacturing the belt. Then, the semiconductive endless belt is attached to the tandem type, intermediate transfer type or tandem intermediate transfer type image forming apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner image formed on a surface of a photoconductor on a recording medium such as paper in an electrostatic recording process in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus. The present invention relates to a semi-conductive endless belt used when transferring and an image forming apparatus equipped with the semi-conductive endless belt.

[0002]

2. Description of the Related Art Conventionally, in the electrostatic recording process of copying machines, printers, etc., first, the surface of a photoconductor (latent image carrier) is uniformly charged, and an image is projected from the optical system onto the photoconductor. The electrostatic latent image is formed by erasing the electrostatic charge on the exposed portion of the light, and then toner is supplied to the electrostatic latent image to form a toner image by electrostatic adhesion of the toner. A method of printing by transferring the image onto a recording medium such as paper, OHP, and photographic paper is adopted. In this case, even in a color printer or a color copying machine, printing is basically performed according to the above process,
For color printing, magenta, yellow, cyan,
To reproduce the color tone by using the black four color toner,
A step is required to obtain a desired color tone by stacking these toners at a predetermined ratio, and in order to perform these steps,
Several methods have been proposed. First, when toner is supplied onto the photoconductor to visualize the electrostatic latent image, the four-color toner images of magenta, yellow, cyan, and black are formed as in the case of monochrome printing. There is a multiple development system. According to this method, it is possible to configure the device relatively compactly, but it is very difficult to control gradation, and there is a problem that high image quality cannot be obtained.

Second, four photosensitive drums are provided, and the latent images of the respective drums are developed with magenta, yellow, cyan, and black toners, respectively, so that the toner image by magenta, the toner image by yellow, and the toner by cyan are developed. By forming four toner images, a black toner image and a black toner image, arranging the photosensitive drums on which these toner images are formed in a line, sequentially transferring each toner image to a recording medium such as paper, and superimposing it on the recording medium. , There is a tandem system that reproduces a color image. Although this method can obtain a good image, four photosensitive drums and a charging mechanism and a developing mechanism provided for each photosensitive drum are arranged in a line, which makes the apparatus large and expensive. Become. FIG. 1 shows a configuration example of a printing unit of a tandem type image forming apparatus. A printing unit composed of the photosensitive drum 1, the charging roller 2, the developing roller 3, the developing blade 4, the toner supply roller 5 and the cleaning blade 6 is provided with four toners corresponding to yellow Y, magenta M, cyan C and black B toners. Toner is sequentially transferred onto a sheet of paper that is lined up and circulated by a driving roller (driving member) 9 and conveyed by a transfer and conveying belt 10 to form a color image. The transfer roller 10 is charged and discharged by the charging roller 7 and the discharging roller 8, respectively. Further, an attraction roller (not shown) is used for charging the sheet to attract the sheet to the belt. With these measures, the generation of ozone can be suppressed. The suction roller loads the sheet from the transport path onto the transfer / transport belt 10 and electrostatically attracts the sheet to the transfer / transport belt 10. Further, the sheet separation after the transfer can be performed only by the curvature separation by lowering the transfer potential to weaken the suction force between the sheet and the transfer / transport belt 10.

By the way, as the material of the transfer / conveyance belt 10, there are a resistor and a dielectric, each of which has its advantages and disadvantages. In the case of using the tandem type transfer, since the resistor belt has a short charge holding time, the charge injection in the transfer is small and the voltage rise is relatively small even in the continuous transfer of four colors. , Because the charge is released even when it is repeatedly used for transferring the next paper,
No electrical reset is required. However, since the resistance value changes due to the environmental change, there are disadvantages that the environmental change influences the transfer efficiency, and the thickness and width of the paper are easily influenced. On the other hand, in the case of the dielectric belt, since the injected charges are not spontaneously released, it is necessary to electrically control both the injection and the release of the charges, but since the charges are stably held, the paper is not attracted. Reliable and highly accurate paper supply can be performed. In addition, since the dielectric constant has low dependency on temperature and humidity, the transfer process is relatively stable even to the environment. However, there is a drawback that the transfer voltage becomes high because the charge is accumulated on the belt every time the transfer is repeated.

As a third method, a recording medium such as paper is wound around a transfer drum and is rotated four times, and magenta, yellow, cyan, and black on the photoconductor are sequentially transferred onto the recording medium for each revolution. There is a transfer drum system that reproduces a color image. According to this method, a relatively high image quality can be obtained, but when the recording medium is a thick paper such as a postcard, it is difficult to wind this around the transfer drum, and the recording medium type is limited. There is a point.

As compared with the above-mentioned multiple development system, tandem system and transfer drum system, good image quality can be obtained, the apparatus does not become large, and the recording medium type is not particularly limited. An intermediate transfer method has been proposed. This intermediate transfer system is provided with an intermediate transfer member composed of a drum and a belt for temporarily holding the toner image on the photosensitive member, and a magenta toner image, a yellow toner image, and a cyan toner image are provided around the transfer member. A color image is formed on the intermediate transfer member by arranging four photoconductors on which a toner image and a black toner image are formed and sequentially transferring the four color toner images onto the intermediate transfer member. Is transferred onto a recording medium such as paper. Therefore, since the gradation is adjusted by superimposing the toner images of four colors, it is possible to obtain a high image quality, and it is possible to reduce the photosensitive member to one by one like the tandem system.
Since there is no need to arrange in line, the device does not become large. Moreover, since it is not necessary to wind the recording medium around the drum, the recording medium type is not limited. There is also a tandem intermediate transfer method in which the tandem method and the intermediate transfer method are combined.

FIG. 2 is a diagram showing an example of the structure of an image forming apparatus for forming a color image by an intermediate transfer system using an endless belt-shaped intermediate transfer member (endless belt) as the intermediate transfer member. In the figure, reference numeral 11 is a drum-shaped photoconductor, which is adapted to rotate in the direction of the arrow in the figure. The photoconductor 11 is charged by the primary charger 12, and then the exposed portion is erased by image exposure 13 to form an electrostatic latent image.
Thus, the electrostatic latent image is developed with the magenta toner M of the first color, so that the magenta toner image of the first color is formed on the photoconductor 11. Next, the toner image is circulated and driven by a driving roller 30 which is a driving member, and is transferred to an intermediate transfer member 20 which is an endless belt that rotates while making contact with the photoconductor 11. Transfer to the intermediate transfer member 20 is performed from the power supply 61 at the nip portion between the photoconductor 11 and the intermediate transfer member 20.
Is performed by the primary transfer bias applied to. After the magenta toner image of the first color is transferred onto the intermediate transfer member 20, the cleaning device 14 causes the photosensitive member 11 to move.
The surface is cleaned, and the first developing and transferring operation of the photoconductor 11 is completed. After that, the photoconductor 11 rotates three times, and the developing devices 42, 43, and 44 are sequentially used for each revolution, and in the same manner as above, the second color cyan toner image, the third color yellow toner image, and the fourth color toner image Black toner images of different colors are sequentially formed on the photoconductor 11 and are formed on the intermediate transfer member 20 for each revolution.
Is superimposed and transferred onto the intermediate transfer member 20 to form a composite color toner image corresponding to the target image. In the image forming apparatus of FIG. 2, the developing devices 41 to 44 are sequentially replaced for each revolution of the photoconductor 11 so that development with the magenta toner M, the cyan toner C, the yellow toner Y, and the black toner B is sequentially performed. It has become.

Next, the transfer roller 25 contacts the intermediate transfer member 20 on which the composite color toner image is formed, and the recording medium 26 such as paper is fed from the paper feed cassette 19 to the nip portion thereof. At the same time, a secondary transfer bias is applied from the power source 29 to the transfer roller 25, and the composite color toner image is transferred from the intermediate transfer member 20 onto the recording medium 26 and heat-fixed. After the synthetic color toner image is transferred to the recording medium 26, the residual toner on the surface of the intermediate transfer member 20 is removed by the cleaning device 35, the intermediate transfer member 20 returns to the initial state, and is ready for the next image formation. ing. Further, as the endless belt-shaped intermediate transfer member (endless belt) 20, a semi-conductive resin film belt and a rubber belt having a fiber reinforcement are mainly used conventionally. Of these,
As a semi-conductive resin film belt, there has been proposed a resin film belt obtained by adding a conductive agent to a resin such as polycarbonate or polyimide.

[0009]

By the way, in the tandem type, intermediate transfer type and tandem intermediate transfer type image forming apparatuses using the above conductive endless belts, each of the endless belts has a resistance in the semi-conductive region. Although it is required to have it, it is the reality that resistance control is difficult. Generally, as a method of controlling the resistance of the belt, a method of adding a conductive substance such as ions, carbon, and metal oxides in a layer made of a resin and controlling the amount added is adopted, When ions are used, the variation in resistance is small, but not only can it cover only a relatively high resistance region,
There are problems that the resistance is easily influenced by the environment, the resistance is easily changed by energization, and the ions are likely to bleed and become a pollution source. On the other hand, when a conductive material such as carbon or a metal oxide is used, the resistance is less likely to be influenced by the environment, the resistance changes less when energized, the contamination problem is less likely to occur, and the necessary resistance region can be covered. Although there are many advantages, there are problems such as large variation in resistance and large voltage dependency of resistance. Therefore, in order to improve the reproducibility and stability of resistance,
Some attempts have been made to add a dispersant together with the conductive substance, but the additive itself causes a new problem that it easily becomes a pollution source.

The present invention has been made in view of the conventional problems, and is a semi-conductive endless belt with a small resistance variation used in a tandem type, an intermediate transfer type and a tandem intermediate transfer type image forming apparatus. Another object of the present invention is to provide an image forming apparatus equipped with the semiconductive endless belt.

[0011]

As a result of intensive studies, the inventors of the present invention have used a conductive agent pre-coated with a resin having a high charge attenuation property as a conductive agent added to a resin layer constituting a belt. As a result, it has been found that a semi-conductive endless belt with less variation in resistance can be stably obtained, and the present invention has been completed. The semiconductive endless belt of the present invention can be used as a transfer member for a tandem type, an intermediate transfer type, and a tandem intermediate transfer type image forming apparatus. That is, the semiconductive endless belt according to claim 1 is a semiconductive endless belt for an image forming apparatus that is cyclically driven by a driving member and transfers a toner image to a storage medium. A conductive agent coated with a resin having a high charge attenuating property in advance is added. Further, the semiconductive endless belt according to claim 2 is cyclically driven by a driving member, and the recording medium held by electrostatic attraction is conveyed to four types of image forming bodies and formed on the surface of each of the image forming bodies. An endless belt used for tandem transfer type transfer / conveyance for transferring the formed toner image to the storage medium, wherein a resin layer forming the belt is coated with a conductive agent having a high charge attenuation property in advance. It is characterized by being added. Further, the semiconductive endless belt according to claim 3 is cyclically driven by a driving member, is disposed between an image forming body and a recording medium, and temporarily transfers the toner image formed on the surface of the image forming body. An endless belt for an intermediate transfer member, which is transferred and held on the surface of a sheet, and is transferred to a storage medium, in which a conductive agent coated beforehand with a resin having a high charge attenuation property is added to a resin layer forming the belt. It is characterized by that. The semiconductive endless belt is generally classified into a jointed type and a jointless type (so-called seamless belt), but any of them may be used in the present invention.

According to a fourth aspect of the semiconductive endless belt, the coating resin is applied to a corona discharger arranged at a distance of 1 mm from the surface of the resin, and the distance is 8 k.
When a voltage of V is applied to generate corona discharge to charge the resin surface, the resin has a maximum surface potential of 300 V or less after 0.3 seconds. The semiconductive endless belt according to claim 5, wherein the amount of the resin to be coated is changed with respect to the conductive agent.
It is set to 0.01 to 50 wt%. In the semiconductive endless belt according to the sixth aspect, the conductive agent is at least one of carbon, metal powder, metal oxide, or a mixture thereof. According to a seventh aspect of the present invention, in the semi-conductive endless belt, in the conductive agent coated with the resin, the solvent insolubility rate of the resin component represented by the following relational expression is 50% or more. Solvent insolubility rate (%) = (B / A) × 100 where A: weight of resin component in resin-coated conductive agent before solvent immersion B; resin-coated conductive agent in a good solvent, 25
Weight of resin component after soaking at 24 ° C. for 24 hours The semiconductive endless belt according to claim 8 has a belt surface roughness of 6 μm or less. An image forming apparatus according to a ninth aspect is characterized in that the semiconductive endless belt according to any one of the first to eighth aspects is mounted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The semiconductive endless belt of the present invention, for example,
The transfer / conveying belt 10 used in the tandem-type image forming apparatus that is driven by the driving member such as the driving roller 9 shown in FIG. 1 and transfers the toner onto the recording medium that is conveyed along with the transfer / conveying belt 10. The toner image formed on the surface of the photoconductor 11 is temporarily transferred by being disposed between the photoconductor 11 and the recording medium 26 such as paper shown in FIG. Then, it is used for the intermediate transfer member 20 and the like used in the intermediate transfer type image forming apparatus for transferring to the recording medium 26.

In the present invention, when a conductive agent is added to the resin forming the resin layer of these semiconductive endless belts,
As the conductive agent, a resin-coated conductive agent is used in advance, which makes the conductive agent uncoated as compared with a case where a normal conductive agent such as carbon or metal oxide is added as it is. As a result, it becomes easy to control the dispersibility of the conductive agent, and it is possible to reduce variations in resistance and voltage dependence of resistance.
At this time, the coating amount of the resin is 0.01 to 50 wt% with respect to the original conductive agent to be coated.
%, Preferably 0.01 to 30 wt%, and more preferably 0.01 to 20 wt%. When the coating amount is less than the above range, sufficient effect of improving the dispersibility cannot be obtained, and when it is more than the above range, sufficient conductivity cannot be obtained as described later. By the way, if the resin is simply coated, naturally, the original conductivity of the conductive agent is impaired, and although the dispersibility can be controlled, the conductivity is hardly exhibited. Therefore, in the present invention, a resin having a high volume resistance but a high charge decay property (fast charge decay) is selected as the resin to be coated on the conductive agent, which is a trade-off between dispersibility and conductivity. Solve a problem.

With respect to the charge decay property, the resin to be coated is formed into a film having a thickness of 3 to 10 μm, and a voltage of 8 kV is applied to a corona discharger arranged at a distance of 1 mm from the film surface to generate corona discharge. Then, the resin surface is charged and the change in the surface potential is measured. In this case, it is important to select, as the resin to be coated, a resin whose maximum surface potential after 0.3 seconds is 300 V or less, preferably 200 V or less. The surface potential is measured, for example, by QEA (Quality Engineering As
sociates, Inc. ) 'S Charge Roller Test System
Measured on CRT2000. FIG. 3 shows a schematic view of the main part. That is, both ends of the shaft 72 of the metallic test roller 71 having the coating resin disposed on the surface thereof are held by the chucks 73, and the small scorotron discharger 8 is provided.
1 and the surface electrometer 82 are separated from each other by a predetermined distance, and the measuring unit 80 is installed on the surface of the subject roller 71 by 1 mm.
The measurement unit 80 is moved from one end to the other end of the subject roller 71 at a constant speed while the subject roller 71 is stationary while the subject roller 71 is kept stationary. A method of measuring the surface potential while applying the surface charge is preferably adopted. Since the surface potential depends on temperature and humidity, it is carried out under an atmosphere of normal temperature and normal humidity (20 ° C./50% RH) as standard conditions. The corona charge applied from the scorotron discharger 81 to the subject roller 71 is a negative charge, and the applied voltage is 8 kV. After applying corona discharge to the subject roller 71,
The speed of the measuring unit 80 is adjusted so that the surface potential after 0.3 seconds is measured.

The resin to be coated may be any resin type as long as it satisfies the above-mentioned conditions of charge attenuation. Examples of the resin to be coated include urethane resin, acrylic resin, polyester resin, urethane-modified acrylic resin, silicone resin, nylon resin, epoxy resin, styrene resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluororesin. And so on. These resins may be used alone or in combination of two or more, and particularly, urethane resin, fluororesin, silicone resin, acrylic urethane resin are preferable, and further, a belt to be described later is constituted. It is preferable that at least one kind of resin that is the same as the resin used in the resin layer is included.

The conductive agent to be coated is a so-called conductive substance, and examples thereof include carbon, metal, metal oxide and the like. For example, conductive carbon such as Ketjen black and acetylene black, SAF, ISA
Carbon for rubber such as F, HAF, FEF, GPF, SRF, FT, MT, carbon for ink subjected to oxidation treatment,
Examples thereof include pyrolytic carbon, natural graphite, or a metal or metal oxide such as antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, or germanium.

As a method of coating the above resin, for example, dispa coat, coat mizer, etc. may be mentioned. The disperse coat is provided with a powder supply section provided at the upper part and a multistage disperser capable of supplying liquid in multiple stages from the lateral direction. The above-mentioned powder supply is controlled by controlling the operating conditions of the multistage disperser. Liquid components including coating resin on the surface of the conductive powder supplied from the
The operation of wetting the surface of the conductive powder with a liquid can be carried out in a very short time. The coatmizer supplies the conductive powder to be coated into a jet jet to form a dispersion layer, and then forms a mist-like stream made of fine particles of a droplet containing a coating resin in a position parallel to this. Then, the surface of the conductive powder is coated with a resin by colliding with the conductive powder to be coated.

With respect to the conductive agent coated with the resin, it is preferable that the solvent insolubility rate of the resin component shown by the following relational expression is 50% or more, particularly 70% or more. Solvent insolubility rate (%) = (B / A) × 100 where A: weight of resin component in resin-coated conductive agent before solvent immersion B; resin-coated conductive agent in a good solvent, 25
Weight of resin component after soaking at 24 ° C. for 24 hours When the solvent insolubility rate is less than 50%, when the semiconductive endless belt is mounted on an electrophotographic apparatus such as a printer, a copying machine or a FAX, it is exposed to light such as OPC. Contamination occurs on the body contact site, causing a problem on the image. As the solvent for measuring the solvent insolubility, methyl ethyl ketone or the like is used for the fluororesin, methanol or the like is used for the polyamide resin, methyl ethyl ketone or toluene is used for the acrylic urethane resin, and melamine resin is used. It is preferable to use acetone, isopanol or the like, and toluene or the like for the silicone resin.

Any material may be used as the resin layer coated with a conductive agent in advance, and examples thereof include polyamide, polyimide, polycarbonate, polyarylate, polyacetal, polypropylene, polyethylene, polyphenylene ether and poly. Sulfone, polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polyetherimide, polybutadiene, polyisobutylene, polyvinyl fluoride, polyvinylidene fluoride, acrylic, acrylic acid alkyl ester copolymer, ethylene tetrafluoroethylene copolymer, hexafluoro Propylene, perfluoroalkyl vinyl ether copolymer, polyester ester copolymer, polyester ether copolymer,
One type or two or more types of polyurethane copolymers can be mixed, and polyamide, polycarbonate, acrylonitrile copolymer, and polyvinylidene fluoride are particularly preferable. In addition, if necessary, in addition to the components described above, for example, various fillers, coupling agents, antioxidants, lubricants, surface treatment agents, within a range that does not impair the effects of the present invention,
Functional components such as a pigment, an ultraviolet absorber, a foaming agent, a cross-linking agent, and a compatibilizing agent may be appropriately blended. The resistance of this resin layer is appropriately selected, but it is preferable to adjust it to a semiconductive region of 10 ⁶ to 10 ¹³ Ω · cm, particularly 10 ⁷ to 10 ¹² Ω · cm. In the semi-conductive region where variations in resistance tend to occur, the variations in resistance can be effectively reduced by adding the conductive agent of the present invention coated with resin in advance. The resin layer may be a single layer or a plurality of layers, and the thickness is appropriately selected, but the range of 50 to 500 μm is usually used.

Further, the semiconductive endless belt of the present invention is, for example, as shown in the sectional view in the belt width direction shown in FIG. 4A, the driving roller 9 in the image forming apparatus of FIG. 1 or the driving roller 9 of FIG. A fitting portion (broken line in the figure) that fits with the fitting portion formed on the driving member may be formed on the surface that contacts the driving portion such as the driving roller 30. The semiconductive endless belt of the present invention To prevent the semi-conductive endless belt from shifting in the width direction by providing such a fitting portion and fitting the fitting portion to a fitting portion (not shown) provided on the driving member to run the semi-conductive endless belt. You can In this case, the fitting portion is not particularly limited, but as shown in FIG. 4A, the fitting portion has a continuous convex shape along the belt circumferential direction (rotational direction), which is a driving roller or the like. It is preferable that the drive member is fitted in a groove formed along the circumferential direction. In addition,
FIG. 4A shows an example in which one continuous convex shape is provided as the fitting portion. In this fitting portion, a large number of convex portions are arranged in a line along the belt circumferential direction (rotational direction). They may abut each other, or, as shown in FIG. 4B, two or more fitting portions may be provided, or they may be provided at the central portion in the width direction of the belt. Further, the fitting portion is not a convex shape as shown in FIGS. 4A and 4B but a groove along the belt circumferential direction (rotational direction), which is used as the driving roller 9 (or the driving roller 9). You may make it fit with the convex part formed along the circumferential direction of drive members, such as roller 30).

The surface roughness of the semiconductive endless belt of the present invention is not particularly limited, but the surface roughness is set to 6 μm or less in JIS ten-point average roughness Rz, further 3 μm or less. It is preferable. Further, as an image forming apparatus using the semiconductive endless belt of the present invention,
The tandem system shown in FIG. 1, the intermediate transfer system shown in FIG. 2, or the tandem intermediate transfer system can be exemplified, but the invention is not limited thereto. In the case of the apparatus of FIG. 2, a voltage can be applied from a suitable power source 61 to the drive roller 30 (or drive gear) that rotates the intermediate transfer member 20 of the present invention. The application conditions can be selected as appropriate, such as application only or application of alternating current over direct current. Further, the manufacturing method of the semi-conductive endless belt of the present invention is not particularly limited, for example, by a twin-screw kneader, kneading the conductive agent previously coated with a resin,
The obtained kneaded product can be manufactured by extrusion molding using a ring die. Alternatively, a powder coating method such as electrostatic coating can be appropriately adopted.

<Example> The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following. [Example 1] Acrylonitrile / butadiene / styrene resin (manufactured by Daicel Polymer: Sebian V680) 100
Parts by weight and the resin coating CB type A shown below are melt-kneaded by a biaxial kneader, and the resulting kneaded product is extruded to form an inner diameter of 245 mm, a thickness of 100 μm, and a width of 2
A semiconductive endless belt having a dimension of 50 mm was obtained. Resin coating CB type A uses Ketjen black carbon (manufactured by Lion), and acrylic urethane resin EAU65B (manufactured by Asia Kogyo) / IPDI cross-linking agent Excel hardener H
X (made by Asia Industry) was selected. The ratio of EAU65B and Excel hardener HX was 6 in terms of solid content weight ratio.
It was adjusted so that it would be 4 pairs. The coating method uses a spiral flow device (made by Freund),
With the Ketjen Black carbon flowing, ME
K-Ketjen black carbon particles in which a solution obtained by mixing the acrylic urethane resin and the cross-linking agent in a solvent K is blown in a mist state to coat the Ketjen black carbon surface with the resin and to heat the resin to pre-coat the resin. Was produced.

[Example 2] In Example 1, resin coating CB type B in which urethane resin DP307 (manufactured by Sanyo Kasei) / IPDI-based cross-linking agent Excel hardener HX (manufactured by Asia Industry Co., Ltd.) was used as the resin to be coated in advance was used. A semiconductive endless belt was produced in the same manner as in Example 1 except for the above. The ratio of DP307 and Excel hardener HX was adjusted so that the solid content weight ratio was 4.5: 1. [Example 3] The same as Example 1 except that the resin constituting the belt was changed from acrylonitrile / butadiene / styrene resin (Sebian V680) to polybutylene terephthalate resin (Daicel Polymer: Novalloy B1700). A semiconductive endless belt was produced in the same manner as in.

Reference Example 1 Semi-conductive material was prepared in the same manner as in Example 1 except that the resin coating CB type C in which the amount of coating resin was increased was adjusted by adjusting the spraying conditions of the coating. A sexless endless belt was produced. [Reference Example 2] Resin coating C used in Example 1 above
In place of B type A, resin coating CB type D in which the resin to be pre-coated in the resin coating CB type A was only acrylic urethane resin EAU65B (manufactured by Asia Kogyo Co., Ltd.) was used, and otherwise the same as in Example 1 above. Then, a semiconductive endless belt was produced.

[Comparative Example 1] Instead of the resin coating CB type A used in the above Example 1, the resin to be pre-coated in the above resin coating CB type A was replaced by
Epoxy resin AER6071 (made by Asahi Kasei) / hardening agent Sumicure M (made by Sumitomo Chemical), resin coating CB
A semi-conductive endless belt was produced in the same manner as in Example 1 except that type E was used. In addition,
The ratio between AER6071 and Sumicure M was adjusted to 7 to 2 before use. [Comparative Example 2] A semiconductive endless belt was produced in the same manner as in Example 1 except that Ketjen Black carbon was used as it was in Example 1 without resin coating.

With respect to the semiconductive endless belts of the examples, reference examples and comparative examples thus produced, the respective characteristics were evaluated according to the following criteria. The results are shown in the table of FIG. The characteristics were measured and the test results were measured according to the following criteria. (1) Charge potential of resin to be coated in advance A metal roller having the same diameter as the charging roller was coated with only the resin to be coated so as to have a thickness of 5 μm to prepare a subject roller. A CRT2000 device manufactured by QEA is used for this sample roller, a voltage of 8 kV is applied to a scorotron discharger arranged at a distance of 1 mm from the sample roller to generate corona discharge, and the surface of the sample roller is charged. The surface potential after 0.3 seconds was measured. The measurement was performed in an atmosphere of normal temperature and normal humidity (20 ° C./50% RH). (2) Amount of resin coated TGA for resin coated beforehand
Using the apparatus, the temperature rising rate is 20 ° C./min. The temperature was raised to 800 ° C. and the amount of coated resin was calculated from the change in weight. (3) Solvent Insolubility The carbon previously resin-coated was immersed in a MEK solution at 25 ° C. for 24 hours, dried at 100 ° C. for 5 hours, and the weight after drying was measured. The solvent insolubility rate was calculated according to the following formula from the amount of resin before immersion from TGA and the weight change before and after immersion. Solvent insolubility rate (%) = (B / A) × 100 Here, A represents the weight of the resin component in the resin-coated conductive agent before the solvent immersion, and B represents the resin-coated conductive agent in a good solvent, 25 The weight of the resin component after soaking at 24 ° C. for 24 hours is shown. (4) Belt Surface Roughness The surface of the semi-conductive endless belt thus produced was measured using a surface roughness measuring device (manufactured by Tokyo Seimitsu: Surfcom 120A).
The ten-point average roughness Rz was measured. (5) Variation in Volume Resistivity and Resistance of Belt The volume resistivity of the semi-conductive endless belt produced was measured at an applied voltage of 250 V using a resistance meter (HIRESTA manufactured by Mitsubishi Petrochemical Electronics Co., Ltd.). Further, the semiconductive endless belt thus produced and the metal drum were pressed against each other with a load of 500 g and rotated, and 250 V was applied between the semiconductive endless belt and the metal drum to make one round of the semiconductive endless belt. The difference between the maximum resistance and the minimum resistance is defined as the resistance variation. (6) Image display and stain test The semiconductive endless belt produced and the OPC drum were pressed against each other with a load of 1000 kg, left at 40 ° C. and 85% RH for 20 days, and then the OPC drum was mounted on the printer device. Then, 10 images were printed, and the contamination state was judged based on the degree of image defects when printing these 10 sheets. At this time, the case where a line-shaped defect occurred at the image position corresponding to the above-mentioned pressure contact portion was determined to be NG.

As is clear from the characteristic measurement results and test results shown in FIG. 5, the semiconductive endless belts of Examples 1 to 3 of the present invention have a small variation in resistance and a stable resistance. When mounted on a printer, a good image could be obtained, and a contamination problem did not occur. On the other hand, in Reference Example 1 in which the coating amount of Example 1 was increased, although the resistance variation was small, the resistance was significantly increased and the surface roughness was deteriorated, and the image had a slightly sandy pattern. Was given. On the other hand, in Reference Example 2 in which the cross-linking agent of Example 1 was omitted, the resistance and the variation in resistance were similar to those in Example 1, but a contamination problem occurred. Further, in Comparative Example 1 in which a resin having a slow charge decay was used as the coating resin, there was a large variation in resistance, and the charging potential was significantly increased. In addition, a sandy pattern was seen in the image and line-shaped defects were generated, resulting in NG. Further, in Comparative Example 2 in which carbon was used as it was without being resin-coated, the resistance value could be adjusted, but the dispersibility was poor, the variation in resistance was large, and a sandy pattern was seen in the image.

[0029]

As described above, according to the present invention,
When a semi-conductive endless belt is produced, a conductive agent coated with a resin having a high charge attenuation property is used as the conductive agent added to the resin layer forming the belt, so that the variation in resistance is small, and It is possible to obtain a semiconductive endless belt having stable resistance.
Further, by providing the semiconductive endless belt to a tandem type, an intermediate transfer type, or a tandem intermediate transfer type image forming apparatus, it is possible to provide an image forming apparatus capable of stably obtaining a good image. You can

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration example of a printing unit of a tandem image forming apparatus.

FIG. 2 is a diagram illustrating a configuration example of an image forming apparatus using an intermediate transfer method.

FIG. 3 is a diagram showing a method of measuring a surface potential.

FIG. 4 is a cross-sectional view in the width direction of a semi-conductive endless belt.

FIG. 5 is a diagram showing a result of trial production of a semiconductive endless belt according to the present invention.

[Explanation of symbols]

1 photoconductor drum, 2 charging roller, 3 developing roller,
4 developing blade, 5 toner supply roller, 6 cleaning blade, 7 transfer roller charging roller, 8
Static eliminator roller, 9 drive roller, 10 transfer conveyance belt, 11 photoconductor, 12 primary charger, 13 image exposure, 14 cleaning device, 19 paper feed cassette, 2
0 intermediate transfer member, 25 transfer roller, 26 recording medium, 29 power source for secondary transfer bias, 30 drive roller, 35 cleaning device for intermediate transfer member, 41 to 4
4 developing device, 61 power source for primary transfer bias, 71
Specimen roller, 72 shaft, 73 chuck, 80
Measuring unit, 81 Scorotron discharger, 82 Surface potential meter.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hajime Kitano             3-5-5 Ogawahigashi-cho, Kodaira-shi, Tokyo F-term (reference) 2H030 AB02 AD05 BB23 BB24 BB42                       BB44                 2H071 BA42 DA09 DA21 EA18                 2H200 GA12 GA23 GA33 GA44 GA47                       GA49 GB12 GB22 HA02 HA12                       HA28 HB03 HB12 HB22 JA02                       JB07 JB08 JB10 JB43 JB45                       JB46 JB47 JC04 JC05 JC13                       JC15 JC16 JC17 LC04 MA02                       MA11 MA12 MA13 MA14 MA17                       MA20 MB01 MB02 MB10 MC06

Claims (9)

[Claims] 1. A semi-conductive endless belt for an image forming apparatus, which is cyclically driven by a driving member and transfers a toner image onto a storage medium, wherein a resin layer constituting the belt comprises:
A semi-conductive endless belt, which is obtained by adding a conductive agent coated in advance with a resin having a high charge attenuation property. 2. A recording medium, which is circulated by a driving member and held by electrostatic attraction, is conveyed to four types of image forming bodies, and the toner images formed on the surfaces of the respective image forming bodies are sequentially transferred to the storage medium. An endless belt used for transfer / transportation of a tandem transfer method for transferring, characterized in that a conductive agent, which is previously coated with a resin having a high charge attenuation property, is added to a resin layer forming the belt. Sex endless belt. 3. A toner image, which is circulated and driven by a driving member, is disposed between an image forming body and a recording medium, and the toner image formed on the surface of the image forming body is once transferred and held on its own surface and stored. An endless belt for an intermediate transfer member for transferring to a medium, characterized in that a conductive agent pre-coated with a resin having a high charge attenuation property is added to a resin layer forming the belt. . 4. The resin to be coated is applied to a corona discharger arranged at a distance of 1 mm from the surface of the resin.
A resin having a maximum surface potential of 300 V or less after 0.3 seconds when the resin surface is charged by applying a voltage of kV to generate corona discharge. The semiconductive endless belt according to any one of claims 1 to 3. 5. The semi-conductive endless according to claim 1, wherein the amount of the resin to be coated is 0.01 to 50 wt% with respect to the conductive agent. belt. 6. The semiconductive endless according to claim 1, wherein the conductive agent is at least one of carbon, metal powder, metal oxide or a mixture thereof. belt. 7. The conductive agent coated with the resin according to any one of claims 1 to 6, wherein a solvent insolubility rate of the resin component represented by the following relational expression is 50% or more. The semiconductive endless belt described. Solvent insolubility rate (%) = (B / A) × 100 where A: weight of resin component in resin-coated conductive agent before solvent immersion B; resin-coated conductive agent in a good solvent, 25
Weight of resin component after immersion for 24 hours at ℃ 8. The semiconductive endless belt according to claim 1, wherein the surface roughness of the belt is 6 μm or less. 9. An image forming apparatus equipped with the semiconductive endless belt according to claim 1. Description: