JPH1039645A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To repeatedly form an image of high quality without affected by the environmental condition, by using an intermediate transfer member having a surface layer which includes at least one kind of urethane resin having an urea group, urethane elastomer and urethane rubber as a binding component, and in which fluroine compound powder is mixed and dispersed. SOLUTION: An intermediate transfer member has at least an elastic layer and a coating layer, the binding component of a surface layer of the intermediate transfer member is at least one kind selected from a group of urethane resin having 2-15weight% of an urea group, urethane elastomer and urethane rubber, and 20-80weight% to the total solid matter in the surface layer, of fluorine compound powder is included in the binding component, in an image forming device. Thereby the dispersibility of the fluorine compound powder can be stabilized, the surface lubricating characteristic of the intermediate transfer member can be improved, and the adhesion of the toner can be reduced, so that the secondary transferring characteristic and the durability can be improved, the filming can be simultaneously prevented, and the abrasion of the photoreceptor can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus in which an image formed on a first image carrier is temporarily transferred onto an intermediate transfer member (primary transfer) and then transferred onto a second image carrier. The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, which obtains an image by further transferring the image (secondary transfer).

[0002]

2. Description of the Related Art An image forming apparatus using an intermediate transfer member includes:
This is effective as a multicolor image forming apparatus that sequentially outputs a plurality of component color images of the multicolor image information by layered transfer and synthesizes and reproduces the multicolor image. It is possible to obtain an image without deviation).

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

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 a medium-resistance elastic roller 6 as an intermediate transfer member.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive member) which is repeatedly used as a first image carrier, and is rotationally driven at a predetermined peripheral speed (process speed) in the direction of an arrow. Is done.

The photoreceptor 1 is uniformly charged to a predetermined polarity and potential by a primary charger (corona discharger) 2 in the course of rotation, and then is subjected to image exposure means (not shown) for color separation of a color original image. An image exposure 3 is performed by an image forming exposure optical system, a traveling 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, and the like. 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 transferred to the first developing device 41.
(Magenta developing device) develops a magenta component image as the first color. At this time, the second to fourth cyan developing devices 42,
Since the yellow developing device 43 and the black developing device 44 are not operating and do not act on the photoconductor 1, the magenta component image of the first color is affected by the second to fourth developing devices 42 to 44. Absent.

[0008] The intermediate transfer member 6 is a cylindrical support member 6.
1 and an elastic layer 62 formed on the outer peripheral surface thereof, and is rotated at the same peripheral speed as the photosensitive member 1 in the direction of the arrow.

[0009] Then, the first
In the process in which the magenta component image of the color passes through the nip portion between the photoconductor 1 and the intermediate transfer member 6, the electric field formed by the primary transfer bias 8 applied to the intermediate transfer member 6 causes the outer periphery of the intermediate transfer member 6 to move. The primary transfer is sequentially performed on the surface.

After the transfer of the first color magenta component image corresponding to the intermediate transfer member 6, the surface of the photosensitive member 1 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 member 6 to correspond to a target color image. A full color image is formed.

A primary transfer bias for sequentially superimposing and transferring the toner images of the first to fourth colors from the photosensitive member 1 to the intermediate transfer member 6 has a polarity opposite to that of the toner and is applied from a bias power supply 8. The applied voltage is in a range of, for example, +2 kV to +5 kV.

Reference numeral 91 denotes a transfer roller, which is provided in parallel with the intermediate transfer member 6 so as to be in contact with the lower surface thereof and is arranged in contact with the lower surface portion. In the transfer process of the color toner image, the transfer roller 91 and the below-described intermediate transfer member cleaner 7 can be separated from the intermediate transfer member 6.

The full-color image superimposed and transferred on the intermediate transfer member 6 has a transfer roller 91 abutting on the intermediate transfer member 6 and a predetermined portion from the paper feed cassette 11 at a contact portion between the intermediate transfer member 6 and the transfer roller 91. The transfer material 10 as the second image carrier is fed at the timing described above, and at the same time, the secondary transfer bias is applied to the transfer roller 91 from the bias power supply 12 to transfer the image onto the transfer material 10 secondarily. 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 member 6 is cleaned by contacting the intermediate transfer member cleaner 7.

The image forming apparatus using the above-mentioned intermediate transfer member is an image forming device for transferring an image from the first image bearing member onto the second image bearing member stuck or adsorbed on the transfer drum. (See, for example, Japanese Unexamined Patent Publication No. 63-301960). That is, (a) the color shift at the time of superimposing the toner images of each color is small. (B) As shown in FIG. 1, there is no need to process or control the second image carrier (for example, to grip, adsorb, and give a curvature to the gripper). The body can be used.

As the second image carrier, for example, 40 g / m
^Two 200 g / m from thin paper ^Two Up to thick paper
It is possible to choose. Wide width of the second image carrier
Transferable regardless of the thickness or thickness
It can handle up to cylinders, postcards, label paper, etc.
is there.

[0018]

As described above, color copying machines and color printers using this image forming apparatus have already begun operating in the market due to the advantages of using an intermediate transfer member. When an image forming apparatus using an intermediate transfer member is actually used repeatedly in various environments, it still has the following problems to be overcome.

(1) The transfer efficiency from a first image carrier, for example, a photoreceptor to an intermediate transfer member, and the transfer efficiency from the intermediate transfer member to a second image carrier, for example, paper or an OHP sheet, are sufficiently high. It has not become something. Therefore, a cleaning device to be provided for the photoconductor and the intermediate transfer member is indispensable, and a large load is applied to the cleaning member for a large amount of transfer residual toner, and the life of the member is shortened, and at the same time, the cleaning device becomes considerably complicated in configuration. , It has become expensive.

(2) The surface properties of the intermediate transfer member may change as the durability of the intermediate transfer member is increased by repeatedly using the intermediate transfer member. In severe cases, scraping occurs on the surface of the intermediate transfer member,
Good transfer efficiency and a uniform image obtained at the beginning cannot be maintained.

(3) As shown in FIG. 1, the intermediate transfer member 6 is provided with an intermediate transfer member cleaner 7. This is an apparatus for removing untransferred toner from the intermediate transfer member before the next series of transfer steps starts.
There are various cleaning methods such as blade cleaning, fur brush cleaning, or a combination thereof. When the cycle of transferring, adhering, and releasing the toner on the surface of the intermediate transfer body 6 is repeated thousands or tens of thousands of times,
The toner that has not been completely removed by the cleaner 7 gradually accumulates on the surface of the intermediate transfer body 6, so that so-called filming is formed. In this case, the transferability of the toner from the first image carrier is deteriorated, resulting in an image having a spot-like white spot due to poor transfer of the filmed portion, and lowering the image quality or lowering the overall transfer efficiency. Invite.

(4) Further, depending on the type of material used for the elastic layer and the coating layer of the intermediate transfer member, it is difficult to obtain a stable image because the transferability greatly changes depending on the environment (temperature and humidity). There is a problem.

However, the present invention proposes an image forming apparatus using an intermediate transfer member which has solved the above-mentioned problems.

An object of the present invention is to provide an image forming apparatus using an intermediate transfer member that can repeatedly obtain high-quality images regardless of the use environment.

[0025]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above objects, and as a result, have found that the binder component of the surface layer of the intermediate transfer member is a urethane resin, elastomer, or rubber having a urea group. It has been found that the above-mentioned objects can be achieved by mixing and dispersing the fluorine-based compound powder in the binder component of at least one of the above, and the image forming apparatus of the present invention has been completed.

That is, the present invention relates to an image forming apparatus for transferring an image formed on a first image carrier onto an intermediate transfer member and further transferring the image onto a second image carrier. At least one selected from the group consisting of a urethane resin, a urethane elastomer and a urethane rubber, in which a binder component of a surface layer of the intermediate transfer member has 2 to 15% by weight of a urea group. In the seed,
An image forming apparatus, wherein the binder component contains 20 to 80% by weight of a fluorine compound powder based on the total solid content of the surface layer.

[0027]

Here, the urea group content indicates the weight% of the portion having the following structure in the binder component. For more information, obtains the content of nitrogen element in the binder component of the surface layer by CHN elemental analysis, determining the ratio of the urethane groups and urea groups from the peak intensity ratio of 1730 cm ^-1 and 1640 cm ^-1 in the IR absorption spectrum. The urea group content in the surface layer was determined from the nitrogen element content in the surface layer and the ratio of urethane groups to urea groups.

[0028]

The object of the present invention is to provide an electrophotographic image forming apparatus in which an image formed on a first image carrier is transferred to an intermediate transfer member and further transferred onto a second image carrier. To achieve this, it is necessary to impart sufficient lubricity to the surface of the intermediate transfer member. Secondary transferability, because the toner adhesion decreases due to the surface lubricity of the intermediate transfer body,
The durability can be improved, filming can be prevented at the same time, and the wear of the photoconductor can be reduced. For that purpose, a method of mixing and dispersing the fluorine-based compound powder in the binder component of the surface layer of the intermediate transfer member is good, but if the binder component is not appropriate,
The fluorine-based compound powder does not disperse or disperses, but the film strength of the surface layer is reduced, and the surface layer suffers from problems such as cracks with durability. In severe cases, a uniform surface layer cannot be formed. Alternatively, there has been a problem that the fluorine compound powder in the surface layer gradually falls off with the endurance, the surface layer becomes rough, and the transfer efficiency decreases. Therefore, in the present invention, the binder component of the surface layer of the intermediate transfer member has a urea group having a high electron donating property in the range of 2 to 15% by weight, and the fluorine compound powder having a high electron withdrawing property is contained in the binder component. By dispersing the toner at a content in the range of 20 to 80% by weight, a stable dispersion of the fluorine compound powder can be achieved, and an intermediate transfer member that can satisfy various properties can be obtained.

If the urea group content is less than 2% by weight, no effect on the dispersibility of the fluorine compound powder is obtained. Also, 1
If it exceeds 5% by weight, it may cause transfer failure in a high temperature and high humidity environment. This is presumably because the water absorption of the urea group is high and the surface layer of the intermediate transfer member is hydrated. As a method of adjusting the content of the urea group, in the step of synthesizing the urethane prepolymer (urethane polymer), the molecular weight of the polyol to be used is adjusted, and the amount of the amine added as a chain extender is adjusted. For example, the amount of isocyanate added at the stage of curing may be adjusted.

In order for the image forming apparatus of the present invention to exhibit desired performance, the fluorine compound powder is 20 to 80% by weight, preferably 30 to 80% by weight, based on the total solid content of the substance constituting the surface layer. It must be contained in the range of 70% by weight. When the content is less than 20% by weight, the lubricating property is insufficiently provided, the secondary transfer efficiency is reduced, and at the same time, filming occurs. If the content exceeds 80% by weight, the surface layer becomes brittle, and the adhesion to the lower layer is reduced, thereby causing problems such as peeling and cracking of the surface layer due to durability.

The fluorine compound powder used in the present invention includes ethylene tetrafluoride resin, ethylene trifluoride ethylene resin, ethylene tetrafluoride hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, and difluoride. One or two or more kinds are appropriately selected from ethylene dichloride resin and their copolymers, fluorocarbon, fluorinated pitch, etc., and particularly, tetrafluoroethylene resin (PTFE) powder is preferable. The molecular weight of the powder and the particle size of the powder can be appropriately selected from commercial grades and used, but the molecular weight is preferably a low molecular weight grade in consideration of lubricity, and the particle size is preferably 0.1 in consideration of dispersibility and surface properties. The range of from 02 to 50 μm is preferred.

In order to prepare a substance constituting the surface layer of the intermediate transfer member, a known method for mixing and dispersing such a fluorine-based compound powder in a binder component such as a resin, an elastomer and a rubber is used. It can be used as appropriate. If the binder component is rubber or elastomer, roll mill,
A device such as a kneader or a Banbury mixer is used. In the case of a liquid, dispersion can be performed using a ball mill, a bead mill, a homogenizer, a paint shaker, a nanomizer, or a similar device.

These fluorine compound powders need to appear on the surface of the intermediate transfer member, and therefore need to be added to the composition constituting the surface layer of the intermediate transfer member. When the intermediate transfer member is composed of a plurality of layers, the fluorine-based compound powder must be dispersed at least in the outermost layer. In the present invention, the surface layer refers to the outermost layer.

The intermediate transfer member used in the present invention has, for example, an elastic body 62 containing rubber, elastomer or resin on the outer peripheral surface of a cylindrical conductive support (core bar) 61.
Further, a drum shape having one coating layer 63 on the outer peripheral surface of the elastic layer 62 (FIG. 2), or a drum shape having two coating layers 63 and 64 on the outer peripheral surface of the elastic layer 62 (FIG. 3) ,
Further, it is possible to select from various types of intermediate transfer members such as an endless belt 65 as shown in FIG. In FIG. 4, reference numeral 92 denotes a transfer charger. In the present invention, the shape of the intermediate transfer member is preferably a drum shape from the viewpoint of color misregistration of image superposition and durability due to repeated use.

The conductive support is made of aluminum, iron, copper,
And can be manufactured using a conductive resin or the like in which a metal or alloy such as stainless steel, carbon or metal particles are dispersed,
As its shape, a cylindrical shape as described above, or a shape in which an axis is passed through the center of the cylinder and the inside of the cylinder is reinforced,
Further, an endless belt shape or the like can be used.

The intermediate transfer member of the present invention is also suitable when an organic photoreceptor having a protective layer is used as the first image carrier. The protective layer is a PT provided outside the charge transport layer.
This is a layer in which FE particles and the like are dispersed. By providing such a protective layer, the primary transfer characteristics from the photosensitive member, which is the first image carrier, to the intermediate transfer member are improved, and image defects such as omission during transfer are reduced. No good image quality and high primary transfer efficiency can be obtained.
For example, if the secondary transfer characteristics of the intermediate transfer member are not sufficient, the transfer residual toner on the intermediate transfer member increases, the actual transfer efficiency does not improve, and image defects such as secondary transfer occur at the same time. become. However, according to the intermediate transfer member used in the present invention, such a problem does not occur, and substantial improvement in transfer efficiency and image quality can be achieved by combination with a photosensitive member using a protective layer.

As the rubber, elastomer and resin used for the elastic layer and the coating layer of the intermediate transfer member used in the present invention, for example, styrene-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, norbornene rubber and the like. 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 copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer and styrene-
Styrene-methacrylic ester copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α -Methyl chloroacrylate copolymer, styrene-
Styrene-based resins such as acrylonitrile-acrylate copolymers (homopolymers or copolymers containing styrene or styrene substituents), vinyl chloride resins, styrene-
Vinyl acetate copolymer, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, polyamide resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, fluororesin, ketone resin, ethylene-ethyl acrylate copolymer , Xylene resin and polyvinyl butyral resin. Further, two or more of these rubbers, elastomers and resins may be used in combination.

Further, as a characteristic of the binder component of the surface layer, the elongation is set to 150 to further improve the durability of the surface layer.
% Or more, tensile strength of 300 kgf / cm ² or more, and 1
Preferably, the tensile stress at the time of 00% elongation is 250 kgf / cm ² or less, and more preferably, the elongation is 250%
As described above, the tensile strength is 400 kgf / cm ² or more and 10
The tensile stress at 0% elongation is 200 kgf / cm ² or less, particularly preferably, the elongation is 350% or more, the tensile strength is 450 kgf / cm ² or more, and the tensile stress at 100% elongation is 150 kgf / cm ² or less. (JIS K-
6301).

As an additive for the intermediate transfer member, carbon black, graphite, carbon fiber, metal powder, conductive metal oxide, organometallic compound, organometallic salt, and conductive polymer may be used.

The thickness of the elastic layer of the intermediate transfer member is preferably 0.5 mm or more, more preferably 1 mm or more, and particularly preferably 1 mm to 10 mm. Further, the film thickness of the coating layer is preferably a thin layer for further transmitting the flexibility of the lower elastic layer to the upper layer or the surface of the photoreceptor, specifically 3 mm or less, more preferably 2 mm or less, particularly It is preferably from 20 μm to 1 mm.

The volume resistivity of the intermediate transfer member is 10 ¹ to 10
It is preferably 10 ¹³ Ω · cm, particularly preferably 10 ² to 10 ² Ω · cm.
It is preferably 10 ¹⁰ Ω · cm.

The intermediate transfer member of the present invention is manufactured, for example, as follows.

First, a metal roll as a cylindrical conductive support (core bar) is prepared. An elastic layer is provided by molding rubber, elastomer, resin, and the like on a metal roll by melt molding, injection molding, dip coating, spray coating, or the like. Next, the material of the coating layer is melt-molded on the elastic layer,
The coating layer is provided by injection molding, dip coating, roll coating or spray coating.

Hereinafter, the present invention will be described in detail with reference to examples.

Example 1 182 mm in diameter and 320 in length
A roller (1) having an elastic layer was obtained by transfer molding a rubber compound having the following composition (numerical parts by weight) on the surface of an aluminum cylindrical roller having a thickness of 5 mm and a thickness of 5 mm using a mold.

Rubber compounding: NBR 100 parts (parts by weight, the same applies hereinafter) Zinc oxide 2 parts Conductive carbon black 15 parts Paraffin oil 25 parts Vulcanizing agent 1 part Vulcanization accelerator 3 parts

Further, a paint having the following formulation was prepared.

Formulation of paint for surface layer: Polyester polyurethane prepolymer I (including solvent) 100 parts Curing agent (including solvent) 5 parts Ethylene tetrafluoride resin powder (particle size: 0.3 μm) 100 parts Dispersing aid 5 parts Conductive Titanium particles (particle diameter 0.6 μm) 10 parts DMF 120 parts

Spray the paint onto the outer peripheral surface of roller (1).
Layer coating to form a coating layer having a thickness of about 50 μm.
After that, it is dried and cured at 80 ° C. for 1 hour and at 120 ° C. for 2 hours.
To obtain an intermediate transfer member having a tough surface layer.
Was. The content of the ethylene tetrafluoride resin powder depends on the surface layer.
It was 65% by weight based on the total solids of the material formed. Ma
Polyester polyurethane prepolymer I (including solvent)
5) Mix 5 parts of curing agent (including solvent) with 100 parts,
Dried at 120 ° C for 2 hours and cured at 120 ° C for 2 hours.
The urea group content of the resin was 10% by weight. This middle
The transcript was treated at 15 ° C./10% Rh, 23 ° C./65% Rh, 3
3 in 3 environments of 0 ° C / 80% Rh (hereinafter abbreviated as 3 environments)
Transfer of intermediate transfer member on 50 × 200mm aluminum plate
Surface of the intermediate transfer body.
1kV with high voltage power supply between the cylinder and the aluminum plate
Apply a voltage and connect a 1 kΩ resistor connected in series with the power supply.
Measure the potential difference before and after and convert it to a current value.
The volume resistance of the intermediate transfer body was determined from the pressure and the current value.
4 × 10 each⁷ Ω, 2 × 10⁷ Ω, 7 × 10 ⁶ 
Ω.

The intermediate transfer member was mounted on the full-color electrophotographic apparatus shown in FIG. 1, and an organic photoreceptor having a protective layer was used as a photoreceptor at 15 ° C./10% Rh and 23 ° C./6.
The transfer efficiency was measured for cyan in a single environment in three environments (hereinafter referred to as three environments) of 5% Rh and 30 ° C./80% Rh. The primary transfer efficiency from the photosensitive member as the first image bearing member to the intermediate transfer member is 94%, 94% and 92%, respectively, and from the intermediate transfer member to 80 g / m ² paper as the second image bearing member. Were 94%, 93%, and 91%, respectively.
In this specification, the primary transfer efficiency and the secondary transfer efficiency are values determined by the following equations:

[0052]

Further, full-color images were output in three environments in order to examine the effect of the environment on the image, but good image quality was obtained in all cases.

Thereafter, in order to confirm the durability of the intermediate transfer member, the intermediate transfer member 6 was attached to the apparatus shown in FIG. 5 and pressed against the aluminum cylinder 101 having a diameter of 80 mm with a total pressure of 5 kg, and a peripheral speed of 120 mm / sec. , A load rotation test of 150,000 rotations continuously was performed.

Thereafter, the intermediate transfer member was mounted on a full-color electrophotographic apparatus shown in FIG.
Full color image print tests were performed on 80 g / m ² paper repeatedly in an environment of Rh. As a result, the same image quality as in the initial stage was obtained even after the endurance test of 10,000 sheets, and the secondary transfer efficiency measured by the same method as above did not substantially decrease to 92%.
Even when the surface of the intermediate transfer member was visually observed, there was no peeling or cracking of the surface layer, and there was no filming of the toner.

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

Photoreceptor: an organic photoreceptor having an undercoat layer, a charge generation layer and a charge transport layer on a conductive support, and a protective layer on which a tetrafluoroethylene resin powder is dispersed on the charge transport layer. Photoconductor surface potential: -750 V Color developer (for all four colors): non-magnetic one-component toner Primary transfer voltage: +800 V Secondary transfer voltage: +2.5 kV Process speed: 120 mm / sec. Development bias: -450V

Example 2 An intermediate transfer member was prepared in the same manner as in Example 1 except that the amount of the curing agent added to the surface layer binder was changed to 10 parts (including a solvent). . Here, the content of the ethylene tetrafluoride resin powder was 63% by weight based on the total solid content of the material constituting the surface layer. In addition, polyester polyurethane prepolymer I
10 parts of a curing agent (including a solvent) was mixed with 100 parts (including a solvent), and the mixture was dried and cured at 80 ° C. for 1 hour and at 120 ° C. for 2 hours. The resulting resin had a urea group content of 14% by weight. .

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and a full-color image was output in order to examine the influence of the environment on the image. Although it was seen from the decrease in the secondary transfer efficiency, generally good image quality could be obtained, and it was judged that it was practical.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in the example, and a full-color image print test was repeatedly performed on 80 g / m ² paper in an environment of 23 ° C./65% Rh. As a result, the same image quality as the initial one was obtained in the durability test of 10,000 sheets. Even if the surface of the intermediate transfer member was visually observed, there was no peeling or cracking of the surface layer, and filming of the toner was not observed. There was no result at all, which was a good result. Table 1 shows the results.

Example 3 In Example 1, the coating composition of the surface layer was changed as follows.

Formulation of paint for surface layer: Polyester polyurethane prepolymer II (including solvent) 100 parts Curing agent (including solvent) 2 parts Powdered ethylene tetrafluoride resin (particle size 0.3 μm) 100 parts Dispersing aid 5 parts Conductive Titanium oxide particles (particle diameter 0.6 μm) 10 parts DMF 250 parts

This coating material is spray-coated on the outer peripheral surface of the roller (1) to form a coating layer having a thickness of about 50 μm, and then dried and cured at 80 ° C. for 1 hour and 120 ° C. for 2 hours to obtain a toughness. An intermediate transfer member having a suitable surface layer was obtained. Here, the content of the tetrafluoroethylene resin powder was 67% by weight based on the total solid content of the material constituting the surface layer. In addition, polyester polyurethane prepolymer II
100 parts of (including the solvent) and 2 parts of the curing agent (including the solvent) were mixed, dried at 80 ° C. for 1 hour, and dried at 120 ° C. for 2 hours, and cured. The resulting resin had a urea group content of 3% by weight. .

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the influence of the environment on the image.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / m ² paper repeatedly at 23 ° C./65% Rh. As a result, extremely slight roughness was thought to have occurred on the surface of the intermediate transfer member after 10,000 sheets of durability, which was thought to be due to the falling off of the tetrafluoroethylene resin, and the transfer efficiency was slightly reduced compared to the initial stage. However, it was judged that the image was practically usable without substantially affecting the image.
Table 1 shows the results.

Example 4 Example 4 was repeated except that the content of the ethylene tetrafluoride resin powder was changed to 25% by weight based on the total solid content of the material constituting the surface layer. An intermediate transfer member was prepared in the same manner as in Example 1.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the influence of the environment on the image.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / m ² paper repeatedly in an environment of 23 ° C./65% Rh. As a result, the secondary transfer efficiency after 10,000 sheets of durability was slightly lower than in the initial stage, and extremely slight toner filming was confirmed by visual observation of the surface of the intermediate transfer member. Was hardly affected, and was judged to be practical.
Table 1 shows the results.

Example 5 Example 5 was repeated except that the content of the ethylene tetrafluoride resin powder was changed to 75% by weight with respect to the total solid content of the material constituting the surface layer. An intermediate transfer member was prepared in the same manner as in Example 1.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the influence of the environment on the image. However, good image quality was obtained in all cases.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / m ² paper repeatedly in an environment of 23 ° C./65% Rh. As a result, even when the surface of the intermediate transfer member after 10,000 sheets of durability was visually observed, very slight cracks in the surface layer were confirmed, but the image was hardly affected, and the image was judged to be practicable. Table 1 shows the results.

Example 6 An intermediate was prepared in the same manner as in Example 1 except that the fluorine-based compound powder mixed and dispersed in the surface layer was changed to vinylidene fluoride resin powder (particle diameter: 0.3 μm). A transcript was prepared.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the effect of the environment on the image. However, good image quality was obtained in all cases.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / m ² paper repeatedly in an environment of 23 ° C./65% Rh. As a result, the secondary transfer efficiency after 10,000 sheets of durability was slightly lower than in the initial stage, and extremely slight toner filming was confirmed by visual observation of the surface of the intermediate transfer member. Was hardly affected, and was judged to be practical.
Table 1 shows the results.

(Example 7) Extrusion molding, steam vulcanization and polishing were performed with the rubber compound of Example 1 to obtain an outer diameter of 150 mm and a width of 3 mm.
A rubber belt having a thickness of 20 mm and a thickness of 0.8 mm was obtained. A surface layer was formed on the rubber belt using the surface layer paint of Example 1.

The obtained belt had an outer diameter of 148.4 mm,
Put on an aluminum cylinder of 320mm width and 2mm thickness,
As in Example 1, the resistance value of the intermediate transfer member was measured in three environments.

Next, the aluminum cylinder was removed, and the obtained intermediate transfer member was measured for resistance and transfer efficiency in three environments in the same manner as in Example 1 using a full-color electrophotographic apparatus shown in FIG. A full-color image was output in order to examine the effect of the image on the image.

Thereafter, the belt was put on an aluminum cylinder, and a load rotation test of 150,000 rotations was performed in the same manner as in Example 1. The belt was repeatedly subjected to 80 g / m 2 at 23 ° C./65% Rh.
^A full-color image print test was performed on ^two papers. As a result, the secondary transfer efficiency after 10,000 sheets durability was slightly reduced compared to the initial stage, and even if the surface of the intermediate transfer member was visually observed,
Although very slight toner filming and cracking were confirmed, it hardly affected the image, and it was determined that the image was practical. Table 1 shows the results.

Comparative Example 1 An intermediate transfer member was prepared in the same manner as in Example 1 except that the surface layer was not formed.

As in Example 1, the resistance value and the transfer efficiency were measured in three environments, and a full-color image was output in order to examine the effect of the environment on the image. However, the transfer efficiency was poor in all the environments. An image having a low density, which is considered to be caused by poor transfer, was obtained, and it was confirmed that there was a practical problem.

As described above, since a problem was confirmed from the beginning, the durability test was not performed.

Comparative Example 2 An intermediate transfer member was prepared in the same manner as in Example 1 except that the amount of the curing agent added to the surface layer binder was changed to 15 parts (including the solvent). . Here, the content of the ethylene tetrafluoride resin powder was 59% by weight based on the total solid content of the material constituting the surface. In addition, polyester polyurethane prepolymer I
15 parts of a curing agent (including a solvent) was mixed with 100 parts (including a solvent), and the mixture was dried and cured at 80 ° C. for 1 hour and 120 ° C. for 2 hours. The resulting resin had a urea group content of 18% by weight. .

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and a full-color image was output in order to examine the influence of the environment on the image. The transfer efficiency was inferior, and a clear decrease in density, which is considered to be caused by poor transfer, was observed, confirming that there was a practical problem.

As described above, since a problem was confirmed from the beginning, the durability test was not performed.

Comparative Example 3 An intermediate transfer member was prepared in the same manner as in Example 3 except that no curing agent was added to the surface layer binder. Here, the content of the tetrafluoroethylene resin powder was 68% by weight based on the total solid content of the material constituting the surface layer. In addition, polyester polyurethane prepolymer II (including solvent) is
No urea group was present in the resin obtained by drying and curing at 120 ° C. for 1 hour and at 120 ° C. for 2 hours.

This paint was spray-coated on the outer peripheral surface of the roller (1) to form a coating layer having a thickness of about 50 μm, and then dried and cured at 100 ° C. for 2 hours to obtain an intermediate transfer member.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the influence of the environment on the image. However, good image quality was obtained in all cases.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / cm ² paper repeatedly at 23 ° C./65% Rh. As a result, the surface of the intermediate transfer member after 10,000 sheets of durability was found to have roughness and numerous cracks, which are thought to be caused by the dropping of the tetrafluoroethylene resin, and filming occurred. And it was confirmed that there was a practical problem. Table 1 shows the results.

Comparative Example 4 Example 1 was repeated except that the content of the ethylene tetrafluoride resin powder was changed to 12% by weight based on the total solid content of the material constituting the surface layer. An intermediate transfer member was prepared in the same manner as in Example 1.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the effect of the environment on the image. However, almost all good image quality could be obtained. .

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1, and a full-color image print test was performed on 80 g / cm ² paper repeatedly at 23 ° C./65% Rh. As a result, when the surface of the intermediate transfer body after 10,000-sheet durability was visually observed, remarkable toner filming occurred, and accompanying this, a remarkable decrease in transfer efficiency and image quality was observed, and there was a problem in practical use. confirmed. Table 1 shows the results.

Comparative Example 5 Example 1 was repeated except that the content of the ethylene tetrafluoride resin powder was changed to 85% by weight based on the total solid content of the material constituting the surface layer. An intermediate transfer member was prepared in the same manner as in Example 1.

The resistance value and the transfer efficiency were measured in three environments in the same manner as in Example 1, and full-color images were output in order to examine the influence of the environment on the image.

Thereafter, a load rotation test of 150,000 rotations was performed in the same manner as in Example 1. When the surface of the intermediate transfer member after the load rotation test was visually observed, peeling of the surface layer was remarkable. No durability test was performed.

[0095]

[Table 1]

[0096]

[Table 2]

[0097]

As described above, in the image forming apparatus, the image formed on the first image carrier is transferred to the intermediate transfer member, and then further transferred onto the second image carrier. The body has at least an elastic layer and a coating layer, and the binding component of the surface layer is a urethane resin, a urethane elastomer, or a rubber having a urea group of 2 to 15% by weight, and a fluorine compound powder is contained in the binding component. 20 to the total solid content of the surface layer
By being dispersed within the range of 80% by weight, an image forming apparatus having good transfer efficiency, durability, filming resistance, and obtained image quality can be obtained regardless of the use environment.

[Brief description of the drawings]

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

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

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

FIG. 4 is a schematic sectional view of a color image forming apparatus using the intermediate transfer member of the present invention.

FIG. 5 is a schematic view of a load rotation test device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Primary charger 3 Image exposure 41-44 Developing device 5 Photoconductor cleaner 6 Intermediate transfer body 61 Metal core 62 Elastic layers 63, 64 Coating layer 65 Intermediate transfer belt 7 Intermediate transfer body cleaner 8 Primary transfer bias power supply 91 Transfer Roller 92 Transfer charger 10 Transfer material 11 Paper cassette 12 Secondary transfer bias power supply 13 Fixer 101 Aluminum cylinder

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Minoru Shimojo 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Atsushi Tanaka 3- 30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Tsunetori Ashina 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki Kobayashi 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. Inside

Claims (6)

[Claims] 1. An image forming apparatus for transferring an image formed on a first image carrier onto an intermediate transfer member, and further transferring the image onto a second image carrier, wherein the intermediate transfer member is at least elastic. At least one selected from the group consisting of a urethane resin having 2 to 15% by weight of a urea group, a urethane elastomer and a urethane rubber, wherein the binder component of the surface layer of the intermediate transfer member has a layer and a coating layer. An image forming apparatus, wherein the binder component contains 20 to 80% by weight of a fluorine-based compound powder based on the total solid content of the surface layer. 2. The image forming apparatus according to claim 1, wherein said intermediate transfer member is a roller. 3. The image forming apparatus according to claim 1, wherein the intermediate transfer member is a belt. 4. The image forming apparatus according to claim 1, wherein said first image bearing member is a photosensitive member having a photosensitive layer on a conductive rigid roller. 5. The image forming apparatus according to claim 1, wherein said first image bearing member is an organic photoreceptor. 6. The image forming apparatus according to claim 1, wherein the first image carrier is an organic photoconductor having a protective layer on a surface.