JPH1145010A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device using an intermediate transfer body which prevents bicolor dust and also adverse effect resulting from the contact of a charge application member with the intermediate transfer body for the generation of a transfer electric field. SOLUTION: The charge application means 507 for applying charges to the face of the intermediate transfer body 501 which is opposite the contact of the intermediate transfer body 501 with an image carrier 100 is provided in the downstream in the direction of the movement of the intermediate transfer body 501 than the area of the contact between the surfaces of the image carrier 100 and intermediate transfer body 501. Here, as the intermediate transfer body 501, the one of which the side being in contact with the image carrier 100 is a high-resistance layer and the side opposite to that being in contact with the image carrier 100 is a medium-resistance layer is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus (copier, printer, facsimile) for transferring a toner image on an image carrier such as a photoreceptor onto transfer paper via an intermediate transfer member.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, in particular, a full-color image forming apparatus, a belt-shaped intermediate transfer member is brought into contact with a photosensitive member, and a toner image is transferred from the photosensitive member onto the intermediate transfer member. The toner image is transferred from the photoreceptor to the transfer paper by performing a primary transfer process and a secondary transfer process of collectively transferring the toner image onto transfer paper.

An image forming apparatus using an intermediate transfer member of this type includes an image forming system in which the intermediate transfer member is formed of a medium-resistance material, and an image forming system in which the intermediate transfer member is formed of a dielectric.
Or, at least an image system in which the surface of the intermediate transfer member to which the toner is transferred is formed of a dielectric material.

In a system using an intermediate transfer member formed of a medium-resistance material, a belt tension roller provided so as to sandwich the photosensitive member for primary transfer from the photosensitive member to a belt-shaped intermediate transfer member. By applying a bias to a member that contacts the intermediate transfer member outside the contact area between the photoconductor and the intermediate transfer member, such as applying a bias to one side of the A transfer electric field can be formed in the contact area. This is because a potential gradient from the contact portion of the bias applying member toward the contact region can be generated on the intermediate transfer member by utilizing the electrical characteristic of medium resistance, thereby forming a transfer electric field in the contact region. As described above, setting the contact portion of the bias applying member for forming the transfer electric field to the intermediate transfer member portion outside the above-mentioned contact region, even if the contact pressure is set high to increase the reliability of the contact, The risk of excessively increasing the contact pressure between the photoreceptor and the intermediate transfer member can be reduced as compared with the case where the intermediate transfer member is in contact with the surface of the photoreceptor. This is advantageous in preventing the resulting print image.
Further, even when a rotating body is used as the bias applying member, the vibration of rotation is hardly transmitted to the photoconductor, and this is advantageous in that the risk of the vibration adversely affecting the process of forming a visible image on the photoconductor is reduced. is there.

However, in a system using an intermediate transfer member formed of a medium-resistance material, when a toner image is superimposed and transferred on the intermediate transfer member, image degradation of so-called two-color dust occurs.

On the other hand, it has been confirmed that, in an image system in which the intermediate transfer member is formed of a dielectric, the above-mentioned two-color dust is not generated or is hardly generated. Therefore, in order to prevent the two-color dust, a system using an intermediate transfer member made of a dielectric is advantageous.

However, in this system, a transfer electric field cannot be formed in the contact area if the bias applying member is in contact with the intermediate transfer member outside the contact area. Therefore, the bias applying member has to be arranged so as to contact the transfer body portion in the contact area, which is disadvantageous in that the print image is adversely affected by the generation of the print image and the vibration.

[0008]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above background, and an object of the present invention is to prevent two-color dust and to prevent a charge on an intermediate transfer member for forming a transfer electric field. An object of the present invention is to provide an image forming apparatus using an intermediate transfer member that can prevent an adverse effect caused by contact of an application member with the intermediate transfer member.

[0009]

According to a first aspect of the present invention, a surface of an image bearing member carrying an image and a surface of an intermediate transfer member to which the image is to be transferred are brought close to each other. After moving, they are moved so that they are separated from each other, and by a predetermined electrical operation, a transfer electric field is formed between the two surface portions that are in contact with each other, so that the image on the image carrier is intermediate. In an image forming apparatus provided with a transfer device for transferring to a transfer body, at a location downstream of the intermediate transfer body in the moving direction of the intermediate transfer body from a location where the surface portions of the image carrier and the intermediate transfer body are in contact with each other, the electrical operation may be performed. Provided is a charge applying means for applying an electric charge to the surface of the intermediate transfer body opposite to the surface contacting the image carrier, the intermediate transfer body, the side contacting the image carrier is a high resistance layer, and Opposite side of contact with image carrier It is characterized in that used as a medium resistance layer.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, there is provided a charge removing means for removing charges applied to the intermediate transfer member from a surface of the intermediate transfer member which comes into contact with the image carrier. It is characterized by having.

According to a third aspect of the present invention, in the image forming apparatus of the second aspect, the opposing electrode of the static eliminator is moved from the position directly behind the static eliminator on the back side of the intermediate transfer body in the moving direction of the intermediate transfer body. , Is provided at a remote location.

According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect, the counter electrode is provided on the upstream side and the downstream side in the moving direction of the intermediate transfer member from the position directly behind the counter electrode. It is assumed that.

According to a fifth aspect of the present invention, in the image forming apparatus of the second aspect, an endless belt is used as the intermediate transfer member, and the static eliminator is disposed so as to face a flat extending portion of the belt. It is characterized by the following.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color copying machine will be described below. FIG. 1 is a schematic configuration diagram of a printer unit of a color copying machine according to the present embodiment. The printer section of the color copying machine includes a photosensitive drum 100 as a latent image carrier or a toner image carrier. Around this photoconductor drum, there are provided a charger 200 as a charging unit, a photoconductor cleaning device 300 including a cleaning blade and a fur brush, a writing optical unit (not shown) as an exposure unit, and a revolver development unit 400 as a development unit. .
Further, the intermediate transfer unit 500 and the paper transfer unit 60
0, a fixing unit using the fixing roller pair 701, a paper feeding unit and a control unit (not shown), and the like. The color copier includes a color scanner as an image reading device (not shown). This color scanner reads Red, Green, and Blue when reading a full-color original.
e (hereinafter, referred to as “R, G, B”) for each color-separated light, and is converted into an electrical image signal.

In this color copying apparatus, in the case of full-color copying, the color scanner reads Bk, C,
If the order is M and Y, the operation is as follows. First,
At the start of the image forming cycle, the photosensitive drum 1
00 starts rotation in the counterclockwise direction of the arrow by driving of a drive motor (not shown). The corona discharge of the charging charger 200 is started, and the photosensitive drum 100 is uniformly charged to a predetermined potential with, for example, a negative charge. The intermediate transfer belt 501 as an intermediate transfer body of the intermediate transfer unit 500 is rotated clockwise by an arrow at the same speed as the photosensitive drum 100.

The intermediate transfer belt 501 includes a primary transfer bias roller 507 as a primary transfer charge applying means, a belt driving roller 508, and a belt tension roller 50.
9, a secondary transfer facing roller 510, a cleaning facing roller 511, and a belt neutralizing roller 512 as a pre-primary transfer neutralizing unit. Each roller is formed of a conductive material, and each roller other than the primary transfer bias roller 507 is grounded. Primary transfer bias roller 507
Has a primary transfer power supply 80 controlled by a constant current or a constant voltage.
1, a predetermined transfer bias can be supplied.

At a predetermined timing, reading of Bk color image data by the color scanner is started. Based on the image data, light writing (for example, raster exposure) with laser light by the writing optical unit is performed on the uniformly charged photosensitive drum 100.
As a result, an electrostatic latent image corresponding to the Bk image data (hereinafter, referred to as a Bk electrostatic latent image; the same applies to C, M, and Y) is formed. The Bk electrostatic latent image is reversely developed by the Bk developing device 401 of the revolver developing unit 400 using negatively charged toner. Thereby, the photosensitive drum 10
A Bk toner image is formed on 0.

The Bk toner image formed on the photosensitive drum 100 is transferred to the surface of the intermediate transfer belt 501 by a transfer electric field in a primary transfer section where the photosensitive drum 100 is in contact with the intermediate transfer belt 501. This transfer electric field is applied to a primary transfer bias roller 507 as primary transfer charge applying means.
And is formed by the charge applied to the intermediate transfer belt 501. The photosensitive drum 10 that has passed through the primary transfer section
The untransferred residual toner remaining on the surface of the photosensitive drum 1
The photosensitive member is removed by the photoreceptor cleaning device 300 for repeated use of 00.

The toner image transferred onto the intermediate transfer belt 501 is conveyed again to the primary transfer section by rotation of the belt. During this conveyance, a pre-transfer charger (hereinafter, referred to as “PTC”) 502 as a pre-transfer charging unit disposed around the intermediate transfer belt 501 so as not to disturb the toner image on the intermediate transfer belt 501, and the paper transfer unit 6
00, a belt static elimination charger 503 as static elimination means,
The belt cleaning blade 504 and the lubricant application brush 505 are set in an inoperative state. That is, PTC5
02 and the belt static elimination charger 503 are in a non-discharge state. The paper transfer unit 600 includes three support rollers 602.
Out of the support roller 602 and the secondary transfer bias roller 605 serving as secondary transfer charge applying means, which are located at the upstream end of the stretched portion facing the secondary transfer facing roller 510 in the transfer paper transport direction. The secondary transfer belt 601 serving as a transfer material carrier is separated from the intermediate transfer belt 501 by a contact / separation mechanism (not shown), and the secondary transfer bias roller 605 is used for secondary transfer. The voltage application by the power supply 802 is stopped. The belt cleaning blade 504 and the lubricant application brush 505 are located at positions separated from the intermediate transfer belt 501 by a separation / contact mechanism (not shown). The point of making these inoperative is the same during the superimposition of the toner images on the intermediate transfer belt 501 described later.

On the photosensitive drum 100 side, the process proceeds to the C image forming process after the Bk image forming process, and starts reading C image data by a color scanner at a predetermined timing. The formation of a C electrostatic latent image is performed by laser light writing using the C image data. After the rear end of the previous electrostatic latent image of Bk has passed, the rotation operation of the revolver developing unit 400 is started immediately. Then, before the leading end of the C electrostatic latent image reaches the developing position, the rotation operation is completed, the C developing device 402 is set to the developing position, and the C electrostatic latent image moving to the developing position is removed. Develop with C toner. For M and Y, similarly to the above-described BK and C, the respective color image data reading, electrostatic latent image formation, and development operations are performed. Thereby, the B sequentially formed on the photosensitive drum 100 is
The k, C, M, and Y toner images are transferred to the intermediate transfer belt 50.
The toner image is transferred onto the same surface of the intermediate transfer belt 501 in order, and a toner image is formed on the intermediate transfer belt 501 in which a maximum of four colors are superimposed.

The superposed toner image formed on the intermediate transfer belt 501 as described above is uniformly charged by the PTC 502, and then is conveyed to the secondary transfer section by rotation of the intermediate transfer belt 501. The transfer paper is sent to a secondary transfer unit where the paper transfer unit 600 faces the intermediate transfer belt 501 at a timing so as to overlap the toner image on the intermediate transfer belt 501.

At this time, the paper transfer unit 600 is
The operation state is set to transfer the transfer sheet to the above-described secondary transfer section. Then, a transfer bias is applied to the secondary transfer bias roller 605 of the paper transfer unit 600 to form a transfer electric field, and the four-color superimposed toner image on the intermediate transfer belt 501 is collectively transferred onto transfer paper. The transfer paper on which the toner image has been transferred passes through the portion facing the transfer paper static elimination charger 606 and is discharged by the charger that has been activated to be separated from the intermediate transfer belt 501. The peeled transfer paper is sent toward the fixing roller pair 701, the toner image is melted and fixed at the nip portion of the fixing roller pair 701, and is sent out of the apparatus main body by the discharge roller pair (not shown) and stacked on a copy tray (not shown). .

On the other hand, the surface of the intermediate transfer belt 501 after the transfer of the toner image onto the transfer paper is neutralized by the belt neutralization charger 503 and a belt cleaning blade 504 pressed against the intermediate transfer belt 501 by a contact / separation mechanism (not shown). To remove the transfer residual toner. Further, in order to improve the cleaning property of the intermediate transfer belt 501 and the transfer property of the toner image to the transfer paper, the lubricant application brush 505 pressed against the intermediate transfer belt 501 by a contact / separation mechanism (not shown).
Thereby, fine particles of zinc stearate 506 as a lubricant formed in a plate shape are applied. Further, the residual charge of the secondary transfer belt 601 after the transfer paper is peeled off is removed by the belt charge removal unit 607. Further, the surface is cleaned by the cleaning blade 608.

The above is a copy mode for obtaining a full-color copy of four colors. However, in the case of a three-color copy mode and a two-color copy mode, the number of specified colors and the number of times are limited. Performs the same operation as described above. In the case of the single color copy mode, only the developing device of the predetermined color of the revolver developing unit 400 is in the developing operation state and the belt cleaning blade 504 and the like are in the operating state until the predetermined number of sheets is completed. The copy operation is performed continuously.

In the apparatus of the present embodiment, the intermediate transfer belt 501 is formed of a belt material having a multilayer structure including a surface layer 501a, an intermediate layer 501b, and a base layer 501c, as shown in the sectional view of FIG. I have. Photoconductor drum 10
The outer peripheral surface side that comes into contact with 0 is the surface layer 501a, and the inner peripheral surface side is the base layer 501c. Further, an adhesive layer 501d for bonding the two layers is interposed between the intermediate layer 501b and the base layer 501c. Among these layers, the surface layer 501a and the intermediate layer 501b are high resistance layers, specifically, layers having a volume resistivity of 10 ¹³ Ωcm or more. The base layer 501d is a medium resistance layer, specifically, 10 ⁸ Ω.
cm 10 to 10 ¹¹ Ωcm. Note that the surface layer and the intermediate layer are separate layers from the viewpoint of separating functions, but may be a single high-low layer. For example, it may have a two-layer structure of a surface layer having a volume resistivity of 10 ¹³ Ωcm and a base layer having a volume resistivity of 10 ⁹ Ωcm.

In this embodiment, the photosensitive drum 10
In a transfer unit (hereinafter, referred to as “primary transfer unit”) that transfers the toner image on the intermediate transfer belt 501 to the intermediate transfer belt 501, the primary transfer bias roller 507 and the belt discharging roller 512 move the intermediate transfer belt 501 to the photosensitive drum 100 side. A nip portion having a predetermined width is formed between the photosensitive drum 100 and the intermediate transfer belt 501 by being stretched so as to be pressed against the intermediate transfer belt 501. As a result, the primary transfer bias roller 507 serving as a charge applying unit for forming a transfer electric field is provided between the intermediate transfer belt 501 and the nip portion where the photosensitive drum 100 and the surface of the intermediate transfer belt 501 are in contact with each other.
In the downstream portion of the moving direction, the electric charge is applied to the surface of the intermediate transfer belt 501 on the side opposite to the surface contacting the photosensitive drum 10 as an electrical operation.

Further, the present embodiment is characterized in that a charge removing means is provided for removing charges applied to the intermediate transfer belt from the surface of the intermediate transfer member which comes into contact with the image carrier.

In the present embodiment, the secondary transfer opposing roller 510 and the cleaning opposing roller 511, which are formed of a conductive material and are grounded, function as opposing electrodes of the belt static eliminator 503. These rollers 51
Reference numerals 0 and 511 are located at positions distant from the position directly behind the belt static elimination charger 503 in the belt moving direction. However, since the base layer of the intermediate transfer belt 501 is a medium resistance layer, the counter electrode effect can be exhibited. For example, the opposing electrode effect can be eliminated even at a location about 10 mm away from the location directly behind. In addition, in the present embodiment, since the belt static eliminator 503 is disposed so as to face the flat spread portion of the belt between the rollers 510 and 511, the belt portion wound around the support roller of the belt, etc. Can be satisfactorily eliminated as compared with the case where static elimination is performed on a plane portion having the curvature of.

In the example shown in FIG. 1, the charge applied to the intermediate transfer belt 501 by the primary transfer bias roller 507 is
The intermediate transfer belt 50 in the nip portion is formed so that an undesired electric field is not formed in the entrance area of the primary transfer portion where the photosensitive drum 100 and the intermediate transfer belt 501 are close to each other.
A grounded belt neutralization brush 513 as a primary transfer unit neutralization means is brought into contact with the inner peripheral surface of the belt 1 to eliminate the charge. The nip width Wn of the primary transfer portion shown in FIG. 3 and the distance L from the downstream end of the nip portion in the belt moving direction to the contact position of the belt neutralization brush 513 are distances corresponding to the effective transfer area. The larger the value is, the higher the transfer rate can be obtained. On the other hand, if the value is too large, the inflection point of the potential gradient, which turns to the potential decrease due to the charge elimination, shifts to the pre-transfer area side to generate a transfer electric field in the pre-transfer area. Therefore, a specific distance is set from the viewpoint of adjusting conflicting requests. (Hereinafter, margin)

[Examples] Next, more specific examples of the color copying apparatus according to the above embodiment will be described. As the intermediate transfer belt 501, an intermediate transfer belt having a thickness of 0.15 mm, a width of 368 mm, and an inner peripheral length of 565 mm was used, and the moving speed of the intermediate transfer belt 501 was 200 mm.
/ Sec. The surface layer 501a of the intermediate transfer belt 501 was formed of an insulating layer having a thickness of about 1 μm. The intermediate layer 501b is an insulating layer (volume resistivity: about 10 ¹³ ) made of PVDF (polyvinylidene fluoride) and having a thickness of about 75 μm.
cm). The base layer 501c is made of PVDF
(Polyvinylidene fluoride) and a medium resistance layer (volume resistivity: 10 ⁸ -10 ¹¹ ) of about 75 μm in thickness made of titanium oxide
Ωcm). When the volume resistivity of the entire intermediate transfer belt formed of such a material was measured, it was 10 ⁷
-10 ¹² Ωcm. Each volume resistivity mentioned above is JIS
Using the measurement method described in K 6911, voltage 1
It was measured by applying 00V for 10 seconds. The surface resistivity of the surface of the intermediate transfer belt 501 on the side of the surface layer 501a was measured using a resistance meter “Hirester I” manufactured by Yuka Denshi.
P "was 10 ⁷ to 10 ¹² Ω / □. This surface resistivity uses the above-mentioned resistance measuring instrument,
It can also be measured by the surface resistance measurement method described in JIS K 6911.

As the primary transfer bias roller 507, a nickel-plated metal roller was used. As the belt neutralizing roller 512, a metal roller was used. As the other rollers, metal rollers or conductive resin rollers were used. The primary transfer bias roller 507 applies 1.0 kV to the first color toner image and 1.3 kV to the second color toner image.
1.4 kV, 1.6 to the third color toner image
1.8 kV, 1.9 to 2.4 for the fourth color toner image.
An appropriate DC transfer bias such as 2 kV was applied.

The nip width Wn of the primary transfer portion is 10 mm
Set to. The distance L from the downstream end of the nip portion in the belt moving direction to the contact position of the belt neutralizing brush 513 is 7 m.
m (see FIG. 3). The belt static elimination brush 51
As No. 3, a conductive material in which carbon-containing resin fibers were implanted was used.

As the PTC 502, a charger with a grid electrode was used. For this PTC 502,
A DC bias voltage having the same polarity as the charging polarity of the toner image on the intermediate transfer belt 501 was applied by the PTC power supply 803. More specifically, the main wire 502a of the PTC 502
, A DC voltage controlled at a constant current of -500 μA was applied, and a DC voltage set within a range of 0 to −3 kV was applied to the grid electrode 502b.

The secondary transfer bias roller 605 includes a surface layer made of conductive sponge or conductive rubber,
A roller having a core layer made of metal or conductive resin was used. A transfer bias controlled at a constant current of 10 to 20 μA was applied to this roller. The secondary transfer belt 601
A belt material made of PVDF (polyvinylidene fluoride) having a thickness of 100 μm and a volume resistivity of 10 ¹³ Ωcm was used.

The transfer sheet static elimination charger 606 is constituted by an AC voltage only or AC + D by a power source (not shown).
A discharger to which C voltage was applied was used. As the belt neutralization charger 607, a discharger to which only an AC voltage or an AC + DC voltage was applied by a power supply (not shown) was used. The cleaning blade 608 was in contact with the portion of the secondary transfer belt 601 wound around the support roller 604 in a counter manner.

In the above embodiment, the photosensitive drum 100 is used as the image carrier, but the present invention can be applied to an image carrier having another shape. For example,
The present invention can also be applied to a photosensitive belt that is stretched between two rollers and moves endlessly.

An intermediate transfer belt 5 is used as an intermediate transfer member.
Although the example using No. 01 has been described, the present invention can also be applied to a device using an intermediate transfer member having another shape.

Further, although an example in which a bias roller is used as the transfer charge applying means has been described, the present invention can also be applied to an apparatus employing a transfer charge applying means having another shape.

Also, the case has been described where the charging potential of the photosensitive drum 100 is negative and a developing device employing a reversal developing method using a two-component developer is provided. The charging potential of 100 is not limited to the one having a negative polarity, and can be similarly applied to those using a one-component developer or those employing a regular development system.

The primary transfer bias roller 507
The values such as the voltage and current of the primary transfer bias applied to the primary transfer charge applying means are not limited to the above examples, and may be set to appropriate values according to various image forming conditions. it can.

[0041]

According to the first to fifth aspects of the present invention, since the side of the intermediate transfer member that contacts the image carrier is the high-resistance layer, two-color dust can be prevented. Also, since the side opposite to the image carrier of the intermediate transfer member is a medium resistance layer,
At a position downstream of the intermediate transfer member in the moving direction of the intermediate transfer member from a position where the image carrier and the surface portion of the intermediate transfer member are in contact with each other, with respect to the surface on the opposite side of the intermediate transfer member from contact with the image carrier, The electric charge applied by the electric charge applying means can generate a potential gradient toward the above-mentioned contact portion to form a transfer electric field at the contact portion. As described above, the electric field can be formed by the charge applying unit at a position downstream of the intermediate transfer member in the moving direction of the intermediate transfer member from the position where the image carrier and the surface portion of the intermediate transfer member are in contact with each other. Adverse effects caused by the contact of the member for use with the intermediate transfer member can be prevented.

In particular, according to the second aspect of the present invention, since the charge is removed from the surface of the intermediate transfer member which comes into contact with the image bearing member by the charge removing means, the high resistance constituting the side of the intermediate transfer member which contacts the image bearing member is provided. It is possible to prevent problems due to the change-up of layers.

According to the third aspect of the present invention, the counter electrode of the charge eliminating means is located on the back side of the intermediate transfer member at a position separated from the position directly behind the charge eliminating means in the direction of movement of the intermediate transfer member. Since it is provided, the portion directly behind the space can be used as a margin for design. Therefore, the degree of freedom of design increases. Even if the intermediate transfer member is provided at a position distant from the position directly behind the intermediate transfer member in the moving direction of the intermediate transfer member, the opposite side of the intermediate transfer member that comes into contact with the image carrier is a medium resistance layer. Can be made to function as a counter electrode for. When the intermediate transfer member is formed in an endless belt shape, a member for another use such as a support member of the belt is used.
It can also be used as the above-mentioned counter electrode by grounding or the like.

According to the fourth aspect of the present invention, the counter electrodes provided on the upstream side and the downstream side of the intermediate transfer member in the moving direction of the intermediate transfer member with respect to the position directly behind the back side, respectively, more effectively exert the counter electrode function. And more favorable static elimination can be performed.

According to the fifth aspect of the present invention, the intermediate transfer body in the form of an endless belt is neutralized by the neutralizing means arranged opposite to the flat extending portion of the belt, so that the intermediate transfer body is wound around the belt supporting roller. The static elimination can be performed better than in the case where static elimination is performed on a flat portion having a curvature such as a belt portion.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus according to an embodiment.

FIG. 2 is an explanatory diagram of an intermediate transfer belt of the apparatus.

FIG. 3 is an explanatory diagram of a transfer area of the apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 photoconductor drum 501 intermediate transfer belt 501a surface layer 501b intermediate layer 501c base layer 501d adhesive layer 507 belt transfer bias roller 503 belt static elimination charger 512 ground roller 513 static elimination brush

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor ▲ Yu ▼ Hideo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Hiroshi Ono 1-3-6 Nakamagome, Ota-ku, Tokyo No. Ricoh Co., Ltd. (72) Inventor Satoshi Uchida 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Katsuya Kawagoe 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. Inside

Claims (5)

[Claims] 1. A surface of an image bearing member carrying an image and a surface of an intermediate transfer member to which the image is to be transferred come into contact with each other after their surface portions approach each other, and then separate from each other. With a transfer device for transferring the image on the image carrier to the intermediate transfer body by forming a transfer electric field between the two surface portions that are in contact with each other by performing predetermined electrical operations. In the forming apparatus, at a portion downstream of the intermediate transfer member in the moving direction of the intermediate transfer member from a portion where the surface portion of the intermediate transfer member contacts with the image carrier, the image transfer member contacts the image transfer member of the intermediate transfer member as the electrical operation. A charge application means for applying an electric charge to the surface on the opposite side to the surface of the intermediate transfer member, wherein the side in contact with the image carrier is the high-resistance layer, and the side opposite to the image carrier is in contact with the image carrier. That we used a medium resistance layer An image forming apparatus symptoms. 2. An image forming apparatus according to claim 1, further comprising a charge removing means for removing charge applied to said intermediate transfer member from a surface of said intermediate transfer member which comes into contact with an image bearing member. Image forming apparatus. 3. An image forming apparatus according to claim 2, wherein said counter electrode of said discharging means is located on a back side of said intermediate transfer member at a position separated from a position directly behind said discharging means in the direction of movement of said intermediate transfer member. An image forming apparatus, comprising: 4. The image forming apparatus according to claim 3, wherein said counter electrode is provided on an upstream side and a downstream side in the moving direction of said intermediate transfer member from a position directly behind said image forming apparatus. . 5. The image forming apparatus according to claim 2, wherein said intermediate transfer member is an endless belt, and said discharging means is arranged to face a flat extending portion of said belt. Image forming device.