JPH1195570A - Production of intermediate transfer drum and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an intermediate transfer drum very small in resistance unevenness and hardly causing the peeling of a conductive substrate from an elastic layer due to long-term use by forming the elastic layer on the conductive substrate whose outer periphery is coated with an adhesive by insert-extrusion molding method, thereby preventing air from entering into the gap between the conductive substrate and the elastic layer. SOLUTION: The elastic layer is formed on the conductive substrate in such a manner that an elastic layer material is extruded by inserting on the conductive substrate whose outer periphery is coated with the adhesive. In such a case, it is preferable that the volume resistivity of the adhesive is lower than that of the elastic layer. When the volume resistivity of the adhesive is higher than that of the elastic layer, there is a case where the resistance unevenness of an intermediate transfer drum due to the irregularities in thickness of an adhesive layer occurs. The extruding rate at the time of extruding the elastic layer is set to <=1000 mm/min. Thus, the electric resistance unevenness of the intermediate transfer drum and the occurrence of the peeling of the conductive substrate from the elastic layer due to by the long-term use can be very effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an intermediate transfer drum and an image forming apparatus having the intermediate transfer drum and using an electrophotographic method, and more particularly, to an image forming apparatus formed on a first image carrier. The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile that obtains an image formed product by temporarily transferring a toner image onto an intermediate transfer drum and further transferring the toner image onto a second image carrier.

[0002]

2. Description of the Related Art An image forming apparatus using an intermediate transfer drum is a multi-color image forming apparatus for sequentially outputting a plurality of component color images of multi-color image information by stacking and transferring the multi-color image and outputting an image formed product. Thus, it is possible to obtain an image free from misalignment (color misalignment) of the superposition of the component color images.

FIG. 1 shows an example of a schematic diagram of an image forming apparatus using an intermediate transfer drum.

The image forming apparatus shown in FIG. 1 is a full-color image forming apparatus (copier or laser beam printer) utilizing an electrophotographic process, and uses an intermediate transfer drum 6 having a medium resistance. Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive member) that is repeatedly used as a first image carrier, and is rotated at a predetermined peripheral speed (process speed) in the direction of an arrow. Photoconductor 1
Is uniformly charged to a predetermined polarity and potential by a primary charger (corona discharger) 2 in the rotation process, and then is exposed to image exposure means (not shown) (a color separation / imaging exposure optical system for a color original image, The image exposure 3 is performed by a scanning exposure system using a laser scanner that outputs a laser beam modulated in accordance with a time-series electric digital pixel signal of image information. In this way, an electrostatic latent image corresponding to a first color component image (for example, a magenta component image) of a target color image is formed on the photoconductor. Next, the electrostatic latent image is developed into a magenta component image of the first color by the first developing device 41 (magenta developing device). At this time, the second to fourth cyan developing units 42, yellow developing units 43, and black developing units 44 are not operating and do not act on the photoreceptor 1, so that the first color magenta component image is影響 is not affected by the fourth developing units 42 to 44. The intermediate transfer drum 6 has a cylindrical support, an elastic layer and a coating layer formed on the outer peripheral surface thereof, and is driven to rotate at the same peripheral speed as the photosensitive member 1 in the direction of the arrow. The primary transfer bias 8 applied to the intermediate transfer drum 6 while the magenta component image of the first color formed on the photoconductor 1 passes through the nip portion between the photoconductor 1 and the intermediate transfer drum 6. The primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer drum 6 by the electric field formed by the above. The surface of the photoconductor 1 on which the transfer of the first color magenta component image corresponding to the intermediate transfer drum 6 has been completed is cleaned by the cleaning device 5. Similarly, a second color cyan component image, a third color yellow component image, and a fourth color black component image are sequentially superimposed and transferred onto the intermediate transfer drum 6 to form a full-color image corresponding to a target color image. Is formed. A primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photoconductor 1 to the intermediate transfer drum 6 is applied from a bias power supply 8 with a polarity opposite to that of the toner. The applied voltage is, for example, in the range of +1 kV to +4 kV. Reference numeral 9 denotes a transfer roller, which is provided in parallel with the intermediate transfer drum 6 so as to bear in parallel with the lower surface of the intermediate transfer drum 6. The first to fourth color toner images are transferred from the photoreceptor 1 to the intermediate transfer drum 6. In the transfer step, the transfer roller 9 and an intermediate transfer drum cleaner 7 described later can be separated from the intermediate transfer drum 6. The transfer roller 9 is brought into contact with the intermediate transfer drum 6 in the full-color image superimposedly transferred on the intermediate transfer drum 6, and is transferred from the paper feed cassette 11 to a contact portion between the intermediate transfer drum 6 and the transfer roller 9 at a predetermined timing. A transfer material 10 as a second image carrier is fed, and at the same time, a secondary transfer bias is applied to a transfer roller 9 from a bias power supply 12 to perform secondary transfer onto the transfer material 10. The transfer material 10 that has received the toner image transfer is introduced into the fixing device 13 and is heated and fixed. After the image transfer to the transfer material 10 is completed, the transfer residual toner on the intermediate transfer drum 6 is cleaned by contacting the intermediate transfer drum cleaner 7.

In a color electrophotographic apparatus having an image forming apparatus using the above-mentioned intermediate transfer drum, a second image carrier is attached or adsorbed on a transfer drum, which is a conventional technique, and the first image carrier is An electrophotographic apparatus having an image forming apparatus for transferring an image from the body, for example,
It is superior to the transfer method described in JP 01960 in the following points. That is, there is little color misalignment at the time of superimposing the toner images of each color. Next, as shown in FIG. 1, transferring the image from the intermediate transfer drum to the second image carrier without requiring any processing or control (for example, gripping by a gripper, adsorbing, giving a curvature, etc.). Therefore, the second image carrier can be variously selected, for example, from a thin paper of about 40 g / m ² to 200 μm.
It is possible to select paper up to as thick as g / m ² .
Further, the transfer can be performed regardless of the width or the length or the length of the length, and can be applied to envelopes, postcards, label paper, and the like.

[0006]

As described above, due to the advantages of using the intermediate transfer drum, color copying machines and color printers using this image forming apparatus have already started operating in the market. At present, the color electrophotographic apparatus does not function as an apparatus that makes full use of the advantages described above and that is truly expected and satisfied by the user.

That is, when providing an image forming apparatus using the intermediate transfer drum, there are problems to be overcome as follows.

[0008] That is, in some cases, due to air mixing between the conductive substrate and the elastic layer, an image may not be partially formed from the beginning. Alternatively, the elastic layer peeled off from the conductive substrate as the durability progressed, and in some cases, an image did not appear partially as described above. Further, there is a problem that it is difficult to obtain uniform and good image quality due to the large unevenness of the electric resistance of the intermediate transfer drum.

An object of the present invention is to provide a method of manufacturing an intermediate transfer drum and an image forming apparatus which solve the above-mentioned problems.

[0010]

According to the present invention, there is provided a method of manufacturing an intermediate transfer drum having an elastic layer on at least a conductive substrate, comprising: inserting an elastic layer material into a conductive substrate having an outer peripheral surface coated with an adhesive; A method for manufacturing an intermediate transfer drum, wherein an elastic layer is formed on a conductive substrate by extrusion molding.

In the image forming apparatus, the image formed on the first image carrier is primarily transferred onto an intermediate transfer member, and then secondarily transferred onto a second image carrier. An image forming apparatus having an intermediate transfer drum manufactured by the above manufacturing method.

In the present invention, the elastic layer of the intermediate transfer drum is insert-extruded and formed on a conductive substrate having an outer peripheral surface coated with an adhesive so that air is not mixed between the elastic layer and the conductive substrate. An image free of transfer loss without transfer is obtained. In addition, the elastic layer and the conductive substrate do not peel off due to long-term use, and a good image can be obtained for a long time. At the same time, resistance unevenness is reduced,
Uniform and good images can be obtained. Further, the manufacturing process is shortened, and the manufacturing cost can be reduced.

Here, when the elastic layer is formed without applying the adhesive to the outer peripheral surface of the conductive substrate, the conductive substrate and the elastic layer are liable to peel off due to long-term use.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is preferable that the volume resistivity of the adhesive is lower than the volume resistivity of the elastic layer. When the volume resistivity of the adhesive is higher than the volume resistivity of the elastic layer, the unevenness of the thickness of the adhesive layer may cause uneven resistance of the intermediate transfer drum. Here, as a method of adjusting the resistance of the adhesive, carbon black, graphite, carbon fiber, metal powder, conductive metal oxide, organic metal compound, organic metal salt, conductive polymer, etc. are mixed in the adhesive.・ It is possible by dispersing.

Here, as a method of forming the elastic layer on the conductive substrate, when the elastic layer is formed into a tube by extrusion molding or the like and the tube is coated on the conductive substrate, a tube-shaped elastic layer is used. When coating the layer, air is easily mixed in between the elastic layer and the conductive substrate.

Further, resistance unevenness of the elastic layer and peeling between the elastic layer and the conductive substrate are likely to occur for the following reasons. As one method of coating a tubular elastic body on a conductive substrate, an elastic layer is formed slightly larger than the conductive substrate, and the elastic layer is coated on the conductive substrate. There is a method of forming an elastic layer on the conductive substrate by bringing the layer into close contact with the conductive substrate and performing a treatment such as vulcanization.However, in order to adhere the conductive layer by compressing a slightly larger elastic layer. The uneven distribution of the conductive agent in the elastic layer promotes uneven resistance, and at the same time, the elastic layer easily separates from the conductive substrate due to durability and the like due to the stress of returning to the elastic layer. . As another coating method, there is a method of spreading an elastic layer formed slightly smaller than the conductive substrate and coating the conductive layer on the conductive substrate. The effect of the conductive agent becomes unstable, and resistance unevenness easily occurs.

As another method of forming the elastic layer on the conductive substrate, there is a method of forming the elastic layer on the conductive substrate using a mold as in injection molding. In this case, the elastic layer material is provided in the mold. Since the pressure applied to the elastic layer material tends to be non-uniform when injecting, the uneven distribution of the conductive agent in the elastic layer material tends to occur, and the resistance unevenness tends to increase.

As another forming method, a sheet-shaped formed elastic layer is wound around a conductive substrate, and the elastic layer and the conductive substrate are brought into close contact with each other by tape winding or the like, and a treatment such as vulcanization is performed. There is a method of forming an elastic layer on a conductive substrate, but also in this case, air is easily mixed into the space between the conductive substrate and the elastic layer, which is not preferable. In addition, when the sheet-like elastic layer material is wound around the conductive substrate, the sheet-like elastic layer material is pulled, so that the conductive agent is likely to be unevenly distributed and resistance unevenness is likely to occur.

Further, when the elastic layer is formed on the conductive substrate by the above-described molding method, the number of steps is larger than when the elastic layer is formed on the conductive substrate by insert extrusion molding. As a result, the manufacturing cost of the intermediate transfer drum increases.

However, when an elastic layer is formed on a conductive substrate by insert extrusion molding, a crosshead die is generally used. However, when a crosshead die is used, a weld line is formed on the elastic layer. May occur, and very slight resistance unevenness may occur due to the difference in the state of the conductive agent between the weld line portion and the other portions. It is possible to suppress the occurrence of such slight resistance unevenness by including epichlorohydrin as the material of the elastic layer. Epichlorohydrin itself has a low resistance, and its resistance can be adjusted without adding a large amount of a conductive agent, or in some cases without adding a conductive agent at all. Therefore, even if a weld line occurs as described above, it is possible to suppress the occurrence of resistance unevenness.

Further, the extrusion speed at the time of insert extrusion molding of the elastic layer on the conductive substrate coated with the conductive adhesive on the outer peripheral surface is 1000 mm / min. By doing so, it is possible to extremely effectively prevent the electric resistance unevenness of the intermediate transfer drum and the occurrence of peeling between the conductive substrate and the elastic layer due to long-term use. Extrusion speed is 1000
mm / min. Exceeding the above causes the peeling of the elastic layer from the conductive substrate due to the resistance unevenness and durability of the intermediate transfer drum. As a cause of the increase in the extrusion speed, the shear force on the elastic layer material becomes too large, It is considered that the stress applied to the elastic material sometimes increases, so that the conductive substrate and the elastic layer are easily separated from each other in resistance unevenness or long-term use.

Therefore, in the image forming apparatus, the image formed on the first image carrier is primarily transferred onto the intermediate transfer drum, and then secondarily transferred onto the second image carrier. By using the intermediate transfer drum obtained in the present invention, uniform and good image quality can be obtained.

The intermediate transfer drum of the present invention has, for example, a two-layer structure (FIG. 2) having an elastic layer 62 containing rubber, elastomer or resin on the outer peripheral surface of a cylindrical conductive substrate (core bar) 61. It is possible to select from various layer configurations such as a three-layer configuration (FIG. 3) having an elastic layer 62 on the outer peripheral surface of the conductive base 61 and further having a coating layer 63 on the outer peripheral surface, as required, as required. it can.

The conductive substrate can be manufactured using a metal or alloy such as aluminum, iron, copper and stainless steel, a conductive resin in which carbon and metal particles are dispersed, and the like, and the shape thereof is as described above. A cylindrical shape, a shape in which a shaft passes through the center of the cylinder, a shape in which the inside of the cylinder is reinforced, and the like.

The rubber, elastomer and resin used for the elastic layer and the coating layer of the intermediate transfer drum used in the present invention are, for example, styrene-elastomer and rubber.
Butadiene rubber, high styrene rubber, butadiene rubber,
Isoprene rubber, ethylene-propylene copolymer, acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, silicone rubber, fluorine rubber, nitrile rubber, urethane rubber, polyamide elastomer, acrylic rubber,
Epichlorohydrin rubber and norbornene rubber; Further, as resins, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene -Acrylate copolymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer) Styrene-methacrylic acid ester copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α-chloroacrylic acid Methyl copolymer and styrene-acrylonitrile-a Styrene-based resins such as acrylate copolymers (homopolymers or copolymers containing styrene or styrene substituents), vinyl chloride resins, styrene-vinyl acetate copolymers, rosin-modified maleic acid resins, phenolic resins, epoxy Resin, polyester resin, polyamide resin, polyethylene, polypropylene,
Examples include an ionomer resin, a polyurethane resin, a silicone resin, a fluorine resin, a ketone resin, an ethylene-ethyl acrylate copolymer, a xylene resin, and a polyvinyl butyral resin. Further, two or more of these rubbers, elastomers and resins may be used in combination. Here, a material containing epichlorohydrin is preferable because resistance unevenness is unlikely to occur.

Further, carbon black, graphite, carbon fiber, metal powder,
A conductive metal oxide, an organic metal compound, an organic metal salt, a conductive polymer, or the like may be used.

The thickness of the elastic layer of the intermediate transfer drum is 0.5 m
m or more, more preferably 1 mm or more, and particularly preferably 1 mm to 10 mm. Further, in the case of having a coating layer, the thickness thereof is preferably a thin layer in order to further convey the flexibility of the lower elastic layer to the upper layer thereon or to the surface of the photoreceptor. Is preferably 2 mm or less, particularly preferably 20 μm to 1 mm.

The volume resistivity of the intermediate transfer drum is 1
It is preferably from 0 ³ to 10 ¹³ Ω · cm.
It is preferably 10 ⁵ to 10 ¹⁰ Ω · cm.

[0029]

The present invention will be described in detail below with reference to examples. In the examples, "parts" indicates parts by weight.

(Example 1) Adhesive (volume resistivity: 10 ^-2 Ω · cm) applied to the outer peripheral surface Diameter 182 mm, length 32
An aluminum cylindrical roller having a thickness of 0 mm and a thickness of 2.5 mm and a rubber compound (volume resistivity of 10 ⁶ Ω · cm) having the following composition (parts by weight) were extruded using a crosshead die at an extrusion speed of 600 mm / min. About 7mm thick on a cylindrical roller by insert extrusion molding with
Of rubber compound was formed. Then, the surface of the rubber compound was tape-wound, and then steam-vulcanized to form a roller having an elastic layer. Further, the roller (1) having an elastic layer having a thickness of 5 mm was obtained by polishing the elastic layer of the roller.

Rubber compounding: NBR 30 parts Epichlorohydrin rubber 70 parts Zinc oxide 2 parts Conductive carbon black 1.5 parts Paraffin oil 10 parts Vulcanizing agent 2 parts Vulcanization accelerator 2 parts

Further, a coating material for a surface layer having the following formulation was prepared.

Formulation of paint for surface layer: 100 parts of solvent-soluble fluororesin 20 parts of curing agent 300 parts of toluene

This paint is spray-coated on the outer peripheral surface of the roller (1) to form a coating layer having a thickness of about 20 μm, and then dried and cured at 80 ° C. for 1 hour and at 120 ° C. for 2 hours. Was obtained. The resistance value of the obtained intermediate transfer drum was 1.0 × 10 ⁷ Ω, and the resistance unevenness of the intermediate transfer drum was 1.2.

Here, the resistance value and the resistance unevenness of the intermediate transfer drum are measured under the following conditions.

<Method of Measuring Resistance Value and Resistance Unevenness of Intermediate Transfer Drum> (1) As shown in FIG. 4, a line pressure is applied between the intermediate transfer drum 6 and the metal roll (φ40) 100 so that their axes are parallel. A contact is made at 40 g / cm, and a DC power supply 101, a resistor 102 having an appropriate resistance, and a potentiometer 103 are connected. (2) The metal roll is driven, and the peripheral speed of the intermediate transfer drum driven by the metal roll is set to 120 mm / sec. Adjust so that (3) A DC voltage of +1000 V is applied from a DC power supply to the circuit for about 5 seconds, and a potential difference Vr across the resistor having a known resistance R at that time is measured by a potentiometer (8 manufactured by FLUKE Co., Ltd.)
7TRUEMS MULTIMETER).
At this time, the maximum value of the potential difference Vr is Vrmax, and the minimum value is Vrmax.
rmin, and the average value is Vrave. The atmosphere at the time of measurement is 23 ± 2 ° C. in temperature and 60 ± 10% Rh in humidity. (4) An average current value I ave flowing through the circuit is obtained from the obtained average potential difference Vr ave.

Average current I ave = Vr ave / R (5) <resistance value of intermediate transfer drum> = applied voltage (+10
00V) / average current value Iave. Also, <resistance unevenness of the intermediate transfer drum> = Vmax / Vmin.

The intermediate transfer drum was mounted on a full-color electrophotographic apparatus shown in FIG. 1, and a full-color image print test was performed on 80 g / m ² paper. As a result, uniform and good images were obtained in all image patterns. Thereafter, the apparatus was mounted on the full-color electrophotographic apparatus shown in FIG. 1 and a durability test was performed on 50,000 full-color images using 80 g / m ² paper, and then a full-color image print test was performed. And a good image was obtained.

The image forming conditions of this embodiment will be described below.

Photoreceptor: Organic photoreceptor Photoreceptor surface potential: -750 V Color developer (for all four colors): non-magnetic one-component toner Primary transfer voltage: +300 V Secondary transfer voltage: +2.0 KV Process speed: 120 mm / sec. Developing bias: -450 V Contact pressure between photosensitive drum and intermediate transfer drum: 40 g at linear pressure
/ Cm Contact pressure between intermediate transfer drum and transfer roller: 10 g at linear pressure
/ Cm

Example 2 An intermediate transfer drum was produced in the same manner as in Example 1 except that an adhesive having a volume resistivity of 10 ¹² Ω · cm was used.

The resistance value and resistance unevenness of the obtained intermediate transfer drum were measured in the same manner as in Example 1.
The resistance was 9 × 10 ⁶ Ω, and the resistance unevenness was 1.8.

Further, this intermediate transfer drum was mounted on the full-color electrophotographic apparatus shown in FIG. 1 in the same manner as in Example 1, and a full-color image print test was carried out. It was confirmed, but it was within the range of no practical problems. Thereafter, the apparatus was mounted on the full-color electrophotographic apparatus shown in FIG. 1 and a durability test was performed on 50,000 full-color images using 80 g / m ² paper, and then a full-color image print test was performed. Although very slight density unevenness was confirmed in the tone image, it was within a range in which there was no problem in practical use.

Example 3 An intermediate transfer drum was prepared in the same manner as in Example 1 except that the composition of the elastic layer was changed as follows (volume resistivity of the rubber compound was 10 ⁶ Ω · cm). Created.

Rubber compounding: NBR 100 parts Zinc oxide 10 parts Conductive carbon black 8 parts Paraffin oil 10 parts Vulcanizing agent 2 parts Vulcanization accelerator 2 parts

The resistance value and the resistance unevenness of the obtained intermediate transfer drum were measured in the same manner as in Example 1.
The resistance was 5 × 10 ⁶ Ω, and the resistance unevenness was 2.1.

Further, this intermediate transfer drum was mounted on the full-color electrophotographic apparatus shown in FIG. 1 in the same manner as in Example 1, and a full-color image print test was carried out. It was confirmed, but it was within the range of no practical problems. Thereafter, the apparatus was mounted on the full-color electrophotographic apparatus shown in FIG. 1 and a durability test was performed on 50,000 full-color images using 80 g / m ² paper, and then a full-color image print test was performed. Although very slight density unevenness was confirmed in the tone image, it was within a range in which there was no problem in practical use.

(Example 4) In Example 1, the extrusion speed was set to 1200 mm / min. An intermediate transfer drum was prepared in the same manner as in Example 1 except that the drum was changed to.

The resistance value and resistance unevenness of the obtained intermediate transfer drum were measured in the same manner as in Example 1.
The resistance was 2 × 10 ⁷ Ω, and the resistance unevenness was 1.6.

The intermediate transfer drum was mounted on a full-color electrophotographic apparatus shown in FIG. 1, and a full-color image print test was conducted on 80 g / m ² paper. As a result, uniform and good images were obtained in all image patterns. Thereafter, the apparatus was mounted on the full-color electrophotographic apparatus shown in FIG. 1, and a durability test was performed on 50,000 full-color images using 80 g / m ² paper, and then a full-color image print test was performed. A slight density increase was observed in the portion (image corresponding to both ends in the longitudinal direction of the intermediate transfer drum). Observation of the intermediate transfer drum after the durability test revealed that a very slight separation of the conductive substrate and the elastic layer was observed at the longitudinal end of the intermediate transfer drum.

Comparative Example 1 An intermediate transfer drum was prepared in the same manner as in Example 1, except that the method of forming the elastic layer was changed as follows.

[0052] The thickness 7mm a rubber compound for an elastic layer of Example 1, the inner diameter 184 mm, length tubular extruded of 330 mm, the adhesive and the tube to the outer peripheral surface (the volume resistivity of 10 ^-2 Ω · cm) 182m diameter coated with
A roller having an elastic layer was obtained by coating the surface of an aluminum cylindrical roller having a length of m, length of 320 mm and thickness of 2.5 mm, tape-wrapping the coated tube surface, and performing steam vulcanization. Then, the roller (2) having a 5 mm-thick elastic layer was obtained by polishing the elastic layer of the roller.

The coating for the coating layer of Example 1 was spray-coated on the outer peripheral surface of the roller (2) to form a coating layer having a thickness of about 2 μm. After drying and curing for an hour, an intermediate transfer drum having a surface layer was obtained. The resistance value of the obtained intermediate transfer drum was 8.7 × 10 ⁶ Ω, and the resistance unevenness of the intermediate transfer drum was 3.8.

Further, this intermediate transfer drum was mounted on the full-color electrophotographic apparatus shown in FIG. 1 in the same manner as in the first embodiment, and a full-color image print test was carried out. Transcription loss) was confirmed. When the cross section of the intermediate transfer drum at the portion where the transfer was generated was cut and confirmed, air was mixed between the conductive substrate and the elastic layer. Further, since a problem was confirmed from the beginning, the durability test was not performed.

Comparative Example 2 An intermediate transfer drum was prepared in the same manner as in Example 1 except that the method of forming the elastic layer was changed as follows.

The rubber compound for an elastic layer of Example 1 was formed into a sheet having a thickness of 1 mm, and this sheet was coated with an adhesive (volume resistivity of 10 ⁻² Ω · cm) on the outer peripheral surface.
It was wound about 7 mm thick on the surface of an aluminum cylindrical roller having a thickness of 2 mm, a length of 320 mm and a thickness of 2.5 mm. After the wound sheet surface was tape-wound, steam vulcanization was performed to obtain a roller having an elastic layer. Thereafter, the elastic layer of the roller is polished to a thickness of 5 m.
Roller (3) having m elastic layers was obtained.

Further, the coating material for the coating layer of Example 1 was spray-coated on the outer peripheral surface of the roller (3) to have a thickness of about 20 μm.
Is formed at 80 ° C. for 1 hour at 120 ° C.
And cured for 2 hours to obtain an intermediate transfer drum having a surface layer. The resistance value of the obtained intermediate transfer drum was 2.5 × 10 ⁷ Ω, and the resistance unevenness of the intermediate transfer drum was 5.4.

Further, this intermediate transfer drum was mounted on the full-color electrophotographic apparatus shown in FIG. 1 in the same manner as in the first embodiment, and a full-color image print test was performed. Transcription loss) was confirmed. When the cross section of the intermediate transfer drum at the portion where the transfer was generated was cut and confirmed, air was mixed between the conductive substrate and the elastic layer. Further, since a problem was confirmed from the beginning, the durability test was not performed.

(Comparative Example 3) In the same manner as in Example 1, except that the adhesive was not applied on the outer peripheral surface of the conductive substrate when the elastic layer was insert-extruded on the conductive substrate. An intermediate transfer drum was prepared.

The resistance value and resistance unevenness of the obtained intermediate transfer drum were measured in the same manner as in Example 1.
The resistance was 1 × 10 ⁷ Ω, and the resistance unevenness was 1.2.

The intermediate transfer drum was mounted on the full-color electrophotographic apparatus shown in FIG. 1, and a full-color image print test was performed on 80 g / m ² paper. As a result, uniform and good images were obtained in all image patterns. Thereafter, the apparatus was mounted on the full-color electrophotographic apparatus shown in FIG. 1, and a durability test was performed using full-color images using 80 g / m ² paper. As a result, there was a part where the image density was extremely low after about 30,000 sheets were output. The durability test was stopped because the image (transferred dropping) began to significantly occur. When the cross section of the intermediate transfer drum at the portion where the transfer slippage occurred was cut and confirmed, peeling of the conductive substrate and the elastic layer was confirmed.

[0062]

As described above, in the method of manufacturing an intermediate transfer drum having an elastic layer on at least a conductive substrate,
An elastic layer material is applied to a conductive substrate having an adhesive applied to its outer peripheral surface,
According to the method for manufacturing an intermediate transfer drum, wherein an elastic layer is formed on a conductive substrate by insert extrusion molding, there is no air mixing between the conductive substrate and the elastic layer, and uneven resistance occurs. It is possible to manufacture an intermediate transfer drum that is extremely small and hardly causes peeling of the conductive substrate and the elastic layer due to long-term use. Further, in an image forming apparatus in which an image formed on a first image carrier is primarily transferred onto an intermediate transfer member, and further secondary-transferred onto a second image carrier, the intermediate transfer member is By using the intermediate transfer drum manufactured as described above, it is possible to obtain an image forming apparatus capable of obtaining an output image of uniform and good image quality for a long period without transfer omission.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a color image forming apparatus using an intermediate transfer drum of the present invention.

FIG. 2 is a schematic sectional view of one example of an intermediate transfer drum of the present invention.

FIG. 3 is a schematic sectional view of one example of an intermediate transfer drum of the present invention.

FIG. 4 is a schematic sectional view of a resistance measuring device for an intermediate transfer drum according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Primary charger 3 Image exposure 41-44 Developing device 5 Photoconductor cleaner 6 Intermediate transfer drum 61 Core metal 62 Elastic layer 63 Coating layer 7 Intermediate transfer drum cleaner 8 Primary transfer bias power supply 9 Transfer roller 10 Transfer material 11 Supply Paper cassette 12 Secondary transfer bias power supply 13 Fixing device 100 Metal roll 101 DC power supply 102 Resistor 103 Potentiometer

Claims (5)

[Claims] 1. A method for manufacturing an intermediate transfer drum having an elastic layer on at least a conductive substrate, wherein an elastic layer material is insert-extruded on a conductive substrate having an outer peripheral surface coated with an adhesive, thereby forming an elastic layer material on the conductive substrate. Forming an elastic layer on the intermediate transfer drum. 2. The method according to claim 1, wherein a volume resistivity of the adhesive is lower than a volume resistivity of the elastic layer. 3. The method according to claim 1, wherein the elastic layer contains epichlorohydrin rubber. 4. The extrusion speed of the elastic layer material is 100.
0 mm / min. 2. The method according to claim 1, wherein:
4. The method for manufacturing an intermediate transfer drum according to any one of claims 1 to 3. 5. An image forming apparatus in which an image formed on a first image bearing member is primarily transferred onto an intermediate transfer member and then secondarily transferred onto a second image bearing member. An image forming apparatus comprising: an intermediate transfer drum manufactured by the manufacturing method according to claim 1.