JPH11288186A - Transfer material carrier, transfer method and device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer belt, a method and a device and an image forming device, capable of excellently cleaning the deposition such as toner on a surface, without coating with a lubricant, so as to prevent the deposition such as the toner from being stuck to the surface. SOLUTION: As the transfer belt 6 for carrying a transfer paper S to which a toner image on a photoreceptor 3 is transferred, one provided with a coating layer on the surface is used so that the width of a crack generated on the surface when the belt 6 is used to carry the transfer paper S is the dimension of the deposition stuck to the surface or below. The coating layer is provided so that for instance, when the average grain diameter of the toner as the deposition is 7-9 μm, the width of the crack generated on the surface of the belt 6 is <=5 μm.

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 such as a copying machine, a printer and a facsimile, a transfer method and an apparatus which can be employed in the image forming apparatus, and a transfer material carrier used in the transfer method and the apparatus It is about.

[0002]

2. Description of the Related Art Conventionally, transfer methods and apparatuses used in image forming apparatuses such as copiers, printers, and facsimile machines include:
Various proposals have been made for transferring a toner image on an image carrier to a transfer material carried on the transfer material carrier by bringing a transfer charge applying means to which a transfer bias voltage is applied into contact with a belt-shaped transfer material carrier. Have been. In this type of transfer method and apparatus, a toner image formed on an image carrier is transferred to a transfer material, and the surface of the transfer material carrier that carries and conveys the transfer material has a surface of the image carrier. Residual toner remaining on the surface, toner floating in the device, paper powder generated from the transfer material, or the like adheres due to electrostatic force or pressure contact. If there is dirt attached to the surface of the transfer material carrier as described above, the back surface of the transfer material carried on the transfer material carrier will be stained. Further, in a device in which a charging member such as a charging roller is in contact with an image carrier, if there is dirt on the transfer material carrier, dirt transferred from the transfer material carrier to the image carrier becomes a surface of the charging member. And may cause charging failure. Further, when the image carrier is in contact with the transfer material carrier to which the toner adheres, the heat of the image carrier is transmitted to the transfer material carrier, and the temperature of the transfer material carrier rises. There is a possibility that the toner on the transfer material carrier is fixed and cannot be removed. When the toner sticks, the transfer material cannot be separated from the transfer material carrier at the time of separation of the transfer material, and a jam due to poor separation of the transfer material occurs. Further, in the apparatus using the recycled toner, it is difficult to remove the recycled toner attached to the transfer material carrier due to the characteristics of the recycled toner, and the cleaning property is very poor.

Conventionally, dirt such as toner and paper dust adhering to the transfer material carrier is removed and cleaned on the surface of the transfer material carrier by a cleaning means such as a cleaning blade. Improving this cleaning property,
Various methods and the like have been proposed to prevent back contamination of the transfer material. For example, Japanese Patent Application Laid-Open No. 8-278707 discloses a lubricant for supplying a lubricant to the surface of a transfer material carrier in order to reduce the friction coefficient of the surface of the transfer material carrier (transfer member) and improve the cleaning property. An image forming apparatus provided with a supply member or a lubricant supply means for supplying a lubricant onto the image carrier is provided so that the lubricant supplied on the image carrier is applied to the surface of the transfer material carrier. An image forming apparatus has been proposed. In Japanese Patent Application Laid-Open No. Hei 8-185060, in order to prevent back contamination of a transfer material, the surface of a transfer material carrier (transfer belt) is formed with a foam film layer, and a toner is formed in a foam cell of the foam film layer. There has been proposed a transfer / conveying belt device capable of capturing the image. Further, Japanese Unexamined Patent Publication No.
In Japanese Patent Application Laid-Open No. 305181, the thickness of the coating layer (surface coat layer) of the transfer material carrier is determined by the particle size of the toner in order to prevent the occurrence of poor cleaning of the surface of the transfer material carrier (transfer belt). Even if a crack (crack) occurs in the surface coat layer, the toner particles can be easily scraped off by a cleaning means (cleaning blade) without being buried in the crack. A transfer / transport device has been proposed.

[0004]

However, when a lubricant is applied to the surface of the transfer material carrier as described in JP-A-8-278707, uneven application of the lubricant tends to occur. In addition, cleaning unevenness due to uneven application of the lubricant may occur. In addition, if a crack occurs in the transfer material carrier, there is a possibility that good cleaning characteristics cannot be obtained even when the above-mentioned lubricant is applied.

Further, when the surface of a transfer material carrier (transfer belt) is formed of a foamed film layer as described in Japanese Patent Application Laid-Open No. 8-185060, the foamed cell toner of the foamed film layer is accumulated. As a result, toner sticking may occur.

Further, as described in JP-A-8-305181, even if the thickness of the coating layer (surface coating layer) of the transfer material carrier is made smaller than the particle size of the toner, the cracks are not removed. There is a possibility that the toner accumulates inside and the toner sticks.

The present inventor conducted experiments on the cleaning characteristics and toner adhesion of various transfer material carriers, and as a result, found out the conditions of the transfer carrier capable of obtaining good cleaning properties without toner adhesion. .

[0008] The above-mentioned problems are caused not only when a toner image is transferred from a latent image carrier (photoconductor) as an image carrier to a transfer material on a belt-shaped transfer material carrier, but also when the latent image carrier is transferred. This also occurs when a toner image is once transferred from a body (photoreceptor) to an intermediate transfer body as an image carrier, and then the toner image is transferred from the intermediate transfer body to a transfer material on a belt-shaped transfer material carrier. What you get.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to satisfactorily clean the adherence of toner and the like on the surface without applying a lubricant.
An object of the present invention is to provide a transfer material carrier capable of preventing adhesion of a deposit such as toner on the surface, a transfer method and apparatus using the transfer material carrier, and an image forming apparatus.

[0010]

According to one aspect of the present invention, there is provided a belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred. A coating layer is provided on the transfer material so that the width of a crack generated on the transfer material supporting surface when used for supporting the transfer material is equal to or smaller than the size of the deposit attached to the surface. It is a feature.

According to a second aspect of the present invention, there is provided a belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein a belt is formed on the surface of the transfer material until cracks occur. A coating layer is provided on the surface so that the elongation ratio when expanded is 8% or more.

According to a third aspect of the present invention, in the transfer material carrier according to the second aspect, the expansion rate when the surface supporting the transfer material is expanded until cracks occur is 20% or less. A coating layer is provided.

According to a fourth aspect of the present invention, there is provided a belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the belt is provided with a transfer material on which a crack is generated. A coating layer is provided on the surface of the transfer material so that the extension rate when extended is at least twice the extension rate when used for supporting the transfer material.

According to a fifth aspect of the present invention, in the transfer material supporting member according to the fourth aspect, the expansion rate when the surface supporting the transfer material is expanded until cracks are generated is used for supporting the transfer material. The coating layer is provided so that the elongation is 5 times or less.

According to a sixth aspect of the present invention, in the transfer material carrier of the first to fifth aspects, the thickness of the coating layer is set to 2 to 4 μm.

According to a seventh aspect of the present invention, there is provided a belt-shaped transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the surface carrying the transfer material has a ten-point average roughness. Rz
Is set to 4Z or less.

According to an eighth aspect of the invention, the transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is in contact with the image carrier, and the transfer charge is transferred to the transfer material carrier. Is a transfer method of transferring the toner image on the image carrier to the transfer material, wherein the transfer material carrier is used to carry the transfer material when used for carrying the transfer material. It is characterized in that a coating layer is provided on the surface such that the width of cracks generated on the surface is equal to or smaller than the size of the deposits on the surface.

According to a ninth aspect of the present invention, the transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and the transfer charge is transferred to the transfer material carrier. By transferring the toner image on the image carrier to the transfer material, wherein the transfer material carrier is extended until cracks occur on the surface supporting the transfer material. It is characterized in that a coating layer is provided on the surface so that the elongation at that time is 8% or more.

According to a tenth aspect of the present invention, in the transfer method of the ninth aspect, the transfer material supporting member has an expansion rate of 20% or less when the transfer material is stretched until cracks occur on the surface supporting the transfer material. In this case, the one provided with the above-mentioned coating layer is used.

According to an eleventh aspect of the present invention, the transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and the transfer charge is transferred to the transfer material carrier. By transferring the toner image on the image carrier to the transfer material, wherein the transfer material carrier is extended until cracks occur on the surface supporting the transfer material. It is characterized in that a coating layer is provided on the surface so that the elongation at that time is at least twice the elongation at the time of using the transfer material.

According to a twelfth aspect of the present invention, in the transfer method according to the eleventh aspect, the transfer material supporting member has an expansion rate when the transfer material is stretched until cracks are generated on a surface supporting the transfer material. Elongation ratio of 5 when used to carry
It is characterized by using the one provided with the above-mentioned coating layer so as to be twice or less.

According to a thirteenth aspect of the present invention, in the transfer method of the eighth to twelfth aspects, the thickness of the coating layer is 2 to 4 μm.

According to a fourteenth aspect of the present invention, the transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and the transfer charge is transferred to the transfer material carrier. To transfer the toner image on the image carrier to the transfer material, wherein the ten-point average roughness Rz of the surface supporting the transfer material is 4 as the transfer material carrier.
Z or less is used.

According to a fifteenth aspect of the present invention, there is provided a belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and the transfer material. A transfer device for transferring a toner image on the image carrier to the transfer material, the transfer device comprising: a transfer charge application unit for applying the transfer charge; and a power supply for applying a transfer bias voltage to the transfer charge application unit. The width of a crack generated on a surface supporting the transfer material when the transfer material carrier is used to support the transfer material by being stretched on a support member is set to be equal to or smaller than the dimension of the deposit attached to the surface. And a coating layer provided on the surface.

According to a sixteenth aspect of the present invention, there is provided a belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and the transfer material, and the transfer charge is brought into contact with the transfer material carrier. A transfer device for transferring a toner image on the image carrier to the transfer material, the transfer device comprising: a transfer charge application unit for applying the transfer charge; and a power supply for applying a transfer bias voltage to the transfer charge application unit. Wherein a coating layer is provided on the surface of the transfer material so that the extension rate when the surface is stretched until cracks are generated is 8% or more. is there.

According to a seventeenth aspect of the present invention, in the transfer device of the sixteenth aspect, the transfer material carrier has an expansion rate of 20% or less when the transfer material is stretched until cracks are generated on the surface supporting the transfer material. In this case, the one provided with the above-mentioned coating layer is used.

The invention according to claim 18 is a belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and the transfer material and contacts the transfer material carrier to transfer the transfer charges. A transfer device for transferring a toner image on the image carrier to the transfer material, the transfer device comprising: a transfer charge application unit for applying the transfer charge; and a power supply for applying a transfer bias voltage to the transfer charge application unit. The extension rate when the transfer material is stretched until cracks occur on the surface supporting the transfer material is twice the extension rate when the transfer material carrier is stretched on the support member and used to support the transfer material. As described above, the present invention is characterized in that the one provided with the coating layer on the surface is used.

According to a nineteenth aspect of the present invention, in the transfer device of the eighteenth aspect, as the transfer material carrier, the expansion rate when the surface supporting the transfer material is extended until cracks are generated, is equal to the supporting member. Stretching the transfer material carrier to be used for supporting the transfer material so that it becomes 5 times or less of the stretching rate.
It is characterized by using the one provided with the above-mentioned coating layer.

The invention of claim 20 is the invention of claims 15 to 19
Wherein the thickness of the coating layer is 2 to 4 μm
It is characterized by being.

According to a twenty-first aspect of the present invention, there is provided a belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and the transfer material, and the transfer charge is brought into contact with the transfer material carrier. A transfer device for transferring a toner image on the image carrier to the transfer material, the transfer device comprising: a transfer charge application unit for applying the transfer charge; and a power supply for applying a transfer bias voltage to the transfer charge application unit. And a ten-point average roughness Rz of the surface supporting the transfer material is 4Z or less.

A latent image forming means for forming a latent image on a latent image carrier as an image carrier, a developing means for developing the latent image on the latent image carrier with toner, 22. An image forming apparatus comprising: a transfer device for transferring a toner image on the latent image carrier to a transfer material on a transfer material carrier; wherein the transfer device is any one of claims 15 to 21. It is characterized by using an apparatus.

A latent image forming means for forming a latent image on the latent image carrier, a developing means for developing the latent image on the latent image carrier with toner, and the latent image carrier Transfer means for transferring the upper toner image to an intermediate transfer member as an image carrier,
22. A transfer device for transferring a toner image on the intermediate transfer member to a transfer material on a transfer material carrier, wherein the transfer device is any one of claims 15 to 21. Is used.

In the transfer material carrier of claim 1, the transfer method of claim 8, the transfer device of claim 15, or the image forming apparatus of claim 22 or 23, when the transfer material is carried, the transfer material is By providing a coating layer on the surface of the transfer material carrier so that the width of the cracks generated on the surface to be supported is equal to or smaller than the size of the attached matter attached to the surface, the attached matter is not buried in the cracks, The deposits can be easily removed.

Here, when the attached matter is a toner,
The coating layer is provided such that the width of the crack is equal to or less than the particle size of the toner. For example, the average particle size of the toner is 7 to 9 μm.
In the case of m, the coating layer is provided so that the width of the crack is not more than the average particle size of the toner (for example, not more than 5 μm).

In the transfer material carrier according to the second aspect, the transfer method according to the ninth aspect, the transfer device according to the sixteenth aspect, or the image forming apparatus according to the twenty-second or twenty-third aspect, cracks occur on the surface supporting the transfer material. Elongation rate of 8 when extended to
%, By providing a coating layer with good elongation on the surface of the transfer material carrier, it is possible to suppress the occurrence of cracks that bury the deposits and to easily remove the deposits.

The transfer material carrier according to the third aspect,
23. The transfer method according to claim 22, the transfer device according to claim 17, or
Alternatively, in the image forming apparatus of 23, a coating layer is provided on the surface of the transfer material carrier so that the elongation rate when the surface is stretched until cracks occur on the surface supporting the transfer material is 20% or less. Even when the cleaning means is brought into contact with the transfer material carrier, the frictional force between the transfer material carrier and the cleaning means is suppressed to a predetermined value or less, and the turning of the cleaning means is prevented.

The transfer material carrier according to claim 4, wherein
23. The transfer method according to claim 18, the transfer device according to claim 18, or the transfer method according to claim 22.
Alternatively, in the image forming apparatus of 23, the extension rate when the transfer material is extended until cracks are generated on the surface carrying the transfer material is twice or more the extension rate when the transfer material carrier is used for carrying the transfer material. Thus, by providing a coating layer on the surface of the transfer material carrier, when the transfer material carrier is used to support the transfer material, it is possible to reliably suppress the occurrence of cracks such as burying the attached matter. Make it easy to remove deposits.

[0038] The transfer material carrier of claim 5, wherein
23. The transfer method according to claim 20, the transfer device according to claim 19, or the transfer method according to claim 22.
Alternatively, in the image forming apparatus of 23, the extension rate when the transfer material is extended until cracks occur on the surface supporting the transfer material is 5 times or less the extension rate when the transfer material carrier is used for supporting the transfer material. By providing a coating layer on the surface of the transfer material carrier, when the transfer material carrier is used to carry the transfer material, the frictional force between the transfer material carrier and the cleaning means can be kept to a predetermined level or less. To prevent the cleaning means from being turned up.

The transfer material carrier according to claim 6 and claim 13.
23. The transfer method of claim 20, the transfer device of claim 20, or 22.
Alternatively, in the image forming apparatus of 23, by setting the thickness of the coating layer of the transfer material carrier to 2 to 4 μm, the generation of the cracks can be surely prevented without the coating layer being scraped below a predetermined value even with time. Can be.

[0040] The transfer material carrier of claim 7, and claim 14.
23. The transfer method of claim 21, the transfer device of claim 21, or 22.
Alternatively, in the image forming apparatus of Item 23, by setting the ten-point average roughness Rz of the surface of the transfer material carrier that supports the transfer material to 4Z or less, it is possible to suppress the occurrence of cracks in which the material is embedded, Can be easily removed.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view of a transfer device using a transfer belt as a transfer material carrier according to the present embodiment, FIG. 3 is a plan view showing a schematic configuration of the transfer device, and FIG.
FIG. 5 is a schematic configuration diagram of an image forming apparatus using the transfer device.
5 is a schematic configuration diagram during a transfer operation of the image forming apparatus illustrated in FIG.

In the transfer device shown in FIG. 2, the belt unit 2 is detachably supported on the main body 1A. The belt unit 2 is a belt-shaped transfer wound around a driving roller 5 and a driven roller 4 as support members for transferring a developed image from a drum-shaped photosensitive member 3 as an image carrier shown in FIG. Transfer belt 6 as material carrier, same belt 6
A DC solenoid 8 and a contact / separation lever 9 for contacting / separating the photosensitive member 3 from / to the photosensitive member 3, a bias roller 11 as a transfer charge applying means for applying a transfer bias to the transfer belt 6 to apply a transfer charge, A contact plate 13 for removing electricity and a belt cleaning device 16 are provided. A high-voltage power supply 12 for applying a voltage to the bias roller 11 is provided in the main body 1A shown in FIG. As shown in FIGS. 2 and 3, the drive roller 5 has a gear 5b connected to a drive motor (not shown) at one end thereof, and is driven to rotate.

The transfer belt 6 is driven by the rotation of the drive roller 5, and at a position facing the photosensitive member 3, a transfer sheet S as a transfer material is provided.
(In the direction of arrow A in FIG. 4). The transfer belt 6, as shown in FIG.
It has a two-layer structure of the base layer 6a and the coating layer 6b. When the electric resistance measured by JIS K6911 is 100 V DC, the surface resistivity of the coating layer 6b is 1 × 10 ⁹ Ω to 1 × 10 ¹² Ω. The base layer 6a
Has a surface resistivity of 1 × 10 ⁷ Ω to 1 × 10 ⁹ Ω and a volume resistivity of 5 × 10 ⁸ Ω · cm to 5 × 10 ¹⁰ Ω · cm.

The driven roller 4 and the driving roller 5 are rotatably supported by a support 7 as shown in FIGS. The support 7 can swing about the support shaft 5 a of the drive roller 5 located downstream of the transfer position with respect to the photoconductor 3 in the transfer paper transport direction indicated by the arrow A. The support 7 is operated by a DC solenoid 8 driven on the transfer position side of the transfer belt 6 by a signal from a control plate 8A. That is, the contact / separation lever 9 is connected to the DC solenoid 8.
Moves the support 7 to move the transfer belt 6 toward and away from the photoconductor 3.

The leading edge of the transfer paper S conveyed in a state where it is aligned with the leading edge position of the toner image formed on the photoreceptor 3 by the registration roller 10 serving as a paper transporting means is controlled by the control plate 8A. Approaching, a drive signal is issued and D
The C solenoid 8 is driven. Therefore,
By driving the solenoid 8, the support 7 comes close to the photoreceptor 3, and the transfer belt 6 contacts the photoreceptor 3, so that the transfer paper S is transferred to the photoreceptor 3 at a position facing the photoreceptor 3.
Nip B that can be transported while contacting
Is formed.

Of the rollers 4 and 5, the roller 4 located on the photoconductor 3 side is configured as a driven roller to the roller 5 on the driving side. As shown in FIG. 3, the surface shape of the driven roller 4 is such that both ends 4a,
4a is formed in a tapered shape, and the transfer belt 6
To prevent biasing. The driven roller 4 is a conductive roller made of metal or the like, but only supports the transfer belt 6 having the electric resistance as described above, and is not electrically directly connected to other conductive members. The drive roller 5 has a function of increasing a gripping force on the transfer belt 6 at the time of driving, and therefore has a function of EPDM rubber, chloroprene rubber,
Alternatively, a material such as silicone rubber is selected.

The bias roller 11 is provided on the downstream side (the left side in FIGS. 4 and 5) of the driven roller 4 in the moving direction of the transfer belt 6 so as to contact the inside of the transfer belt 6. The bias roller 11 constitutes a contact electrode for applying a charge having a polarity opposite to the charge polarity of the toner T on the photoconductor 3 to the transfer belt 6, and is connected to a high-voltage power supply 12. In this embodiment, since the positive polarity toner T is used, the polarity of the transfer bias is negative.

The contact plate 13 is disposed in contact with the inner surface of the belt near the driven roller 4 on the lower side of the transfer belt 6 which is not the transfer paper transport surface. It suppresses charge injection. The contact plate 13 is for detecting a current flowing on the transfer belt 6 as a feedback current, and a current supplied from the bias roller 11 is controlled by detecting the current.
For this reason, the transfer control plate 1 for setting the supply current to the bias roller 11 according to the detection current is provided on the contact plate 13.
4 is connected, and the transfer control plate 14
It is connected to the.

In such a transfer / transport apparatus 1, as shown in FIG. 5, the support 7 moves the transfer belt 6 closer to the photosensitive member 3 as the transfer paper S is fed out from the registration roller 10. The transfer nip portion B having a width of about 4 to 8 mm corresponding to the length along the transfer direction of the transfer paper is formed between the transfer nip and the photosensitive member 3.

On the other hand, the surface of the photosensitive member 3 is, for example,-
The toner T is charged to 800 V, and as shown in FIG. 7, the toner T moves to the transfer nip portion while the positively charged toner T is electrostatically attracted to the surface. The photoreceptor 3 is arranged near the photoreceptor 3 before reaching the nip portion, and its surface potential is reduced by a pre-transfer neutralization lamp (PTL) 15 that weakens the charge on the surface of the photoreceptor 3. In FIG. 7, the height of the charged charges is represented by the size of a circle, and the state in which the charged charges are reduced by the pre-transfer charge removing lamp 15 is shown smaller than the circle before the charge removal.

In the transfer nip portion B shown in FIG. 5, the toner T on the photosensitive member 3 is transferred onto the transfer paper S by a transfer bias from the bias roller 11 located on the transfer belt 6 side. The transfer bias ranges from -1.5 kV to -6.
The voltage is applied from the high voltage power supply 12 in the range of 5 kV, because the transfer bias is variably set as a result of constant voltage control described later. That is, in FIGS. 4 and 5, the current value output from the high-voltage power supply 12 is I _1, and the value when the feedback current value flowing from the contact plate 13 to the ground via the transfer belt 6 is I ₂ . If you, between these two, to control the value of I ₁ so that the relation of the following equation is obtained.

I ₁ −I ₂ = Iout (where Iout: constant) This is due to changes in environmental conditions such as temperature and humidity and the transfer belt 6.
This is because the change in transfer efficiency is eliminated by stabilizing the surface potential Vp on the transfer paper S irrespective of the variation in the production quality of the transfer paper. That is, the transfer belt 6
And the current flowing through the transfer paper S to the photoconductor 3 side is Iou
T, the transfer belt 6 is formed by lowering or increasing the surface resistance Vp on the transfer paper S.
This prevents a change in the ease of current flow to the transfer paper S from affecting the separation performance and transfer performance.
In this embodiment, Iout is the transfer speed of the transfer belt 33.
At 0 mm / sec and an effective bias roller length of 310 mm, good transfer was obtained when Iout = 35 μA ± 5 μA.

When the transfer of the toner image from the photosensitive member 3 is performed, the transfer paper S is also charged at the same time. Therefore, the transfer paper S is electrostatically attracted to the transfer belt 6 and the transfer paper can be separated from the photoconductor 3 by the relationship between the true charge of the transfer belt 6 and the polarization charge generated on the transfer paper S side. . This separation is promoted by the peeling operation of the transfer paper S using its stiffness utilizing the curvature separation of the photoconductor 3. However, in such electrostatic attraction, when the humidity is high, an electric current easily flows through the photoconductor 3 due to a change in environmental conditions, so that the transfer paper cannot be separated properly. For this reason,
Since the resistance value of the coating layer 6b of the transfer belt 6 shown in FIG. 6 is set slightly higher, the transfer of the true charge to the transfer paper S at the transfer nip portion B is delayed, and the bias roller 11 Is located downstream of the transfer nip B in the transfer paper transport direction. Thus, the transfer of the true charges from the transfer belt 6 to the transfer sheet S is delayed, and the electrostatic attraction between the transfer sheet S and the photoconductor 3 is avoided.

To delay the transfer of the true charge used in this case means that no charge is generated on the transfer sheet S upstream from the transfer sheet S to the transfer nip portion B on the photosensitive member 6 side. I have. This prevents the transfer paper S from being wound around the photoconductor 3 and also prevents the transfer paper S from separating from the photoconductor 3 from being poorly separated.

Further, it is preferable that a material having a small resistance change due to an environmental change is also selected on the transfer belt 6 side. As a conductive material for controlling the resistance, an appropriate amount of carbon, zinc oxide or the like is added, and an elastic belt is formed. When a rubber belt is used, it is desired to select a material having low hygroscopicity and a stable resistance value, such as chloroprene rubber, EPDM rubber, silicone rubber, and epichlorohydrin rubber. In addition,
The value of the current Iout flowing to the photoconductor 3 side is not unique, and can be reduced, for example, when the transport speed is low.
If 5 is not used, it will increase.

On the other hand, the transfer paper S passing through the transfer nip portion B
Is transported in accordance with the movement of the transfer belt 6, and the drive roller 5 separates the curvature. Therefore, the driving roller 5
Is set to 16 mm or less. Further, when such a driving roller 5 is used, high quality 45K paper is used.
(Stiffness transverse 21 [cm ^3/100]) experimental result that separation is possible of is obtained.

The transfer paper S separated from the transfer belt 6 by the driving roller 5 is guided by a guide plate and conveyed between a heating roller 17a and a pad roller 17b constituting a fixing unit 17. The fixing unit 17 heats and melts the toner on the transfer paper S and presses the toner on the transfer paper S to fix the toner on the transfer paper S. When the transfer and separation of the toner image onto the transfer sheet S are completed, the contact / separation lever 9 is released in response to the release of the excitation of the DC solenoid 8, and the support member 7 or the photosensitive member 3 is released.
Separated from

As shown in FIGS. 4 and 5, the cleaning device 16 is provided with a cleaning blade 16A as a cleaning means. When the transfer belt 6 is rubbed, the toner transferred from the photoconductor 3 is not transferred. Thus, the toner that has scattered around the transfer belt 6 and the paper dust of the transfer paper S are scraped off. The toner T and paper dust scraped off from the surface of the transfer belt 6
The waste toner is collected from the main body 1A into a waste toner collecting container (not shown) by the collecting screw 16B.

The transfer belt 6 rubbed by the cleaning blade 16A is a fluorine-based material having a low friction coefficient in order to prevent an increase in driving force due to an increase in rubbing resistance or a phenomenon such as turning up of the cleaning blade 16A. Resin material, for example. A coating layer of polyvinyldene fluoride, ethylene tetrafluoride or the like is provided on the surface. An additive may be added to the fluorine-based resin material as needed.

Further, in the present embodiment, as shown in the following examples, in order to improve the cleaning characteristics of the transfer belt 6 and prevent toner from sticking to the transfer belt 6,
In a state where the transfer belt 6 is stretched between the driven roller 4 and the drive roller 5, the surface of the transfer belt 6 is prevented from having a crack having a predetermined width or more, the transfer belt 6 is prevented from having a crack, and the transfer is performed. Surface roughness R of belt 6
The coating layer 6b of the transfer belt 6 is provided so that z (ten-point average roughness) is equal to or less than a predetermined value.

[Embodiment 1] When a large crack is generated on the surface of the transfer belt 6, there is a possibility that deposits such as toner on the transfer belt 6 are caught and accumulated in the crack and adhere to the place. is there. Therefore, in this embodiment, the width of the cracks generated on the surface supporting the transfer paper when stretched around the driven roller 4 and the driving roller 5 for use in supporting the transfer paper causes the toner or the like to adhere to the surface. The coating layer 6b having good elongation was provided so as to be smaller than the size of the deposit.

FIG. 1 shows that various transfer belts 6 are used when the average particle size of the toner is 7 to 9 μm in the above-described transfer device.
An experimental result of measuring a relationship between a crack generated in the transfer belt 6 and a cleaning property is shown. The horizontal axis in the figure is the width of a crack generated on the surface of the transfer belt 6 when the belt is stretched over the driven roller 4 and the driving roller 5 and is measured using an optical microscope. The vertical axis in the figure is the result of observing the cleaning performance of the transfer belt 6, where rank 3 is a result of good cleaning characteristics, rank 2 is a result of partial cleaning failure, and rank 1 is a cleaning failure (toner failure). (With fixation). As can be seen from FIG. 1, when the width of a crack generated when extending and stretching the driven roller 4 and the driving roller 5 is 5 μm or less, which is smaller than the particle diameter of the toner,
Good cleaning characteristics without toner adhesion were obtained.

[Embodiment 2] In this embodiment, the extension rate of the transfer belt 6 when the transfer sheet is extended until a crack is generated on the surface carrying the transfer paper (hereinafter referred to as "extension rate at the time of occurrence of a crack"). The coating layer 6b with good elongation was provided so as to be 8% or more. Table 1 shows experimental results obtained by examining the relationship between the elongation ratio at the time of occurrence of a crack and the presence / absence of toner sticking using various transfer belts 6 in the above-described transfer device. Table 1
In the column of cleaning performance, “○” indicates that no toner was fixed up to 240k sheets, “△” indicates that some toner was fixed, and “×” indicates that toner was fixed from the beginning. The results are shown. As can be seen from Table 1,
When the elongation at the time of crack generation was 8% or more, good cleaning characteristics were obtained, and no toner was fixed on the transfer belt 6.

[Table 1]

Embodiment 3 In this embodiment, the transfer belt 6
Is twice as high as the expansion rate when the paper is stretched over the driven roller 4 and the driving roller 5 and used to carry the transfer paper (hereinafter, referred to as the "elongation rate at the time of stretching"). The coating layer 6b was provided as described above. FIG. 8 shows an experimental result obtained by measuring the relationship between the ratio of the two elongation ratios (elongation ratio when a crack occurs / elongation ratio when stretched) and the cleaning property of the surface of the transfer belt 6 in the transfer device. .
The vertical axis in the figure is the result of observing the cleaning performance of the transfer belt 6, where rank 3 is a result of good cleaning characteristics, rank 2 is a result of partial cleaning failure, and rank 1 is a cleaning failure (toner adhesion is present). ). From FIG. 8, the cleaning blade 16
In consideration of deterioration with time, such as deterioration at a contact portion with A, it is not sufficient to simply use the transfer belt 6 having a high elongation at the time of occurrence of the crack.
It was found that when the elongation at the time of occurrence of cracks was twice or more the elongation at the time of stretching, good cleaning characteristics free from toner sticking over time could be obtained.

[Embodiment 4] When a transfer belt with good elongation is used to suppress the occurrence of cracks as in Embodiment 2 above, a cleaning blade is used as a cleaning means for the transfer belt 6 as in this embodiment. This makes it easy for the cleaning blade to be turned (entangled). Therefore, in the present embodiment, the coating layer 6 is formed so that the extension rate of the transfer belt 6 at the time of occurrence of a crack becomes 20% or less.
b was provided. Table 2 shows experimental results obtained by examining the relationship between the elongation rate at the time of occurrence of a crack and the presence or absence of the turning-up of the cleaning blade, using various transfer belts 6 in the transfer device. "O" in the column of presence / absence of turning in Table 2 indicates a result in which no turning occurred. As can be seen from Table 2, when the elongation at the time of crack generation was 20% or less, no turning of the cleaning blade occurred.

[Table 2]

[Embodiment 5] In the case where a transfer belt with good elongation is used to suppress the occurrence of cracks as in Embodiment 3 above, if a cleaning blade is used as a cleaning means for the transfer belt 6 as in this embodiment. This makes it easy for the cleaning blade to be turned (entangled). Therefore, in the present embodiment, the coating layer 6b is provided so that the extension rate of the transfer belt 6 when a crack occurs is 5 times or less the extension rate when the transfer belt 6 is stretched. FIG. 9 shows the relationship between the ratio of the two elongation ratios (elongation ratio at the time of occurrence of cracks / elongation ratio at the time of stretching) and the turn-up (roll-in) of the cleaning blade using various transfer belts 6 in the above-described transfer device. The experimental results obtained are shown. The vertical axis in the figure is the result of observing the turning of the cleaning blade, and corresponds to the result of OK without turning and the result of NG with turning. As can be seen from FIG. 9, the transfer belt 6 did not turn up when the extension rate of the transfer belt 6 at the time of occurrence of a crack was 5 times or less the extension rate at the time of stretching.

[Embodiment 6] In this embodiment, the thickness of the coating layer 6b of the transfer belt 6 is set to 2 to 4 μm in the transfer device.
m. The thickness of the coating layer 6b of the transfer belt 6 is preferably 2 μm or more in consideration of the deviation with time. FIG.
Shows the results of an experiment that measured the relationship between the thickness of the coating layer 6b of the transfer belt 6 and the elongation (%) when cracks occurred. From FIG. 10, it can be seen that if the thickness of the coating layer 6b is smaller than 2 μm, the elongation at the time of occurrence of the crack exceeds 20%, and there is a risk that the cleaning blade is turned up. However, the thickness of the coating layer 6b is preferably 2 μm or more. μm is required.

FIGS. 11 and 12 show the thickness of the coating layer 6b of the transfer belt 6, the surface of the belt 6 in the axial direction parallel to the axes of the rollers 4 and 5, and the circumferential direction along the moving direction of the belt, respectively. The results of an experiment measuring the relationship between the roughness (ten-point average roughness) Rz and the cleaning characteristics of the transfer belt surface are shown. In the figure, the measurement point indicated by the symbol “◇” indicates the result of cleaning failure, and the measurement point indicated by the symbol “□” indicates the result of obtaining good cleaning characteristics. As can be seen from FIGS. 11 and 12, when the thickness of the coating layer 6b is increased, cracks are likely to occur, and good cleaning characteristics cannot be obtained. Therefore, the thickness of the coating layer 6b is 4 μm or less. There is a need.

From the experimental results shown in FIGS. 11 and 12, the surface roughness (ten-point average roughness) Rz of the transfer belt 6 is 4 points.
It was also found that when the value was Z or less, the surface of the transfer belt 6 could be satisfactorily cleaned. In particular, in order to ensure good cleaning characteristics over time and good cleaning characteristics when a solid image is formed, the surface roughness (ten-point average roughness) Rz of the transfer belt 6 is set to 4Z or less. It is necessary.

Further, when the amount of wear of the edge of the cleaning blade 16A was measured in each of the above-described embodiments, when the transfer belt 6 having good cleaning characteristics was used, the amount of wear of the edge of the cleaning blade 16A was reduced to 0.1%. It was possible to keep the thickness within the range of 5 to 5 μm, and the life of the cleaning blade could be improved as compared with the conventional case. On the other hand, when a transfer belt having a crack that causes cleaning failure was used, the amount of wear of the edge of the cleaning blade 16A was 8 to 15 μm. By reducing the wear amount of the edge of the cleaning blade 16A in this manner, the life of the cleaning blade is improved, and it is possible to reduce the running costs of the entire transfer device including the transfer conveyance system and the entire image forming device. Was.

As described above, according to the present embodiment, the transfer belt 6
The toner on the surface of the transfer belt 6 can be satisfactorily cleaned without applying a lubricant to the toner, and the toner can be prevented from sticking to the surface. Therefore, it is possible to prevent the occurrence of poor charging of the photoconductor and the occurrence of back contamination of the transfer paper due to poor cleaning of the transfer belt, and to prevent the transfer paper from being jammed due to the toner sticking to the surface of the transfer belt.

According to the present embodiment, the transfer belt 6
The amount of wear of the cleaning blade for cleaning the surface of the cleaning blade can be reduced, and the life of the cleaning blade can be improved.

Further, according to the present embodiment, the transfer belt 6
Even if foreign matter such as paper dust generated from transfer paper adheres to the surface of the paper, it can be easily removed and cleaned with a cleaning blade. Therefore, it is necessary to provide a member such as a paper dust removing mylar of a conventional apparatus. Therefore, the cost of the apparatus can be reduced.

The present invention can be applied without limitation to the configurations of the transfer apparatus and the image forming apparatus shown in FIGS. 2 to 7 except for the configuration of the surface of the transfer belt. Is obtained. For example, in the above-described embodiment, the bias roller 11 to which a transfer bias voltage is applied is used as the transfer charge applying means. However, instead of this, a transfer charger or a main material such as acrylic, nylon, polyester, or polypropylene may be used, such as carbon. A brush member made of fibers or the like blended with a conductive material or the like may be used. Further, the installation position of the transfer charge applying means is
Either the downstream side or the upstream side of the transfer nip in the belt moving direction may be used, or the transfer nip may be inside the transfer nip.

In the above embodiment, the case where the transfer belt having the two-layer structure is used has been described.
The present invention can be applied to a case where a transfer belt having more than two layers is used.

Further, the present invention can be applied without being limited to the charging polarity of the toner, the charging polarity of the photosensitive member, the reversal development and the normal development.

In the above embodiment, the case where one bias roller is provided as the transfer charge applying means has been described. However, the present invention can be applied to the case where a plurality of transfer charge applying means is provided. .

In the above embodiment, the case where the toner image is directly transferred from the photoconductor 3 to the transfer paper carried on the transfer belt 6 has been described. However, the present invention is directed to a latent image such as a drum-shaped photoconductor. Latent image forming means for forming a latent image on the carrier, developing means for developing the latent image on the latent image carrier with toner, and intermediate transfer of the toner image on the latent image carrier as an image carrier An image forming apparatus such as a color printer or a color copier including a transfer unit for transferring an intermediate transfer member such as a belt and a transfer device for transferring a toner image on the intermediate transfer member to a transfer material on a transfer material carrier. It can also be applied to

[0078]

According to the first, eighth, fifteenth, twenty-second, and twenty-third aspects of the present invention, the deposits are not buried in the cracks generated on the surface of the transfer material carrier, and the deposits can be easily removed. Therefore, it is possible to satisfactorily clean the attached matter such as the toner on the surface without applying the lubricant, and to prevent the attached matter such as the toner from being adhered to the surface.

According to the inventions of claims 2, 9, 16, 22 and 23, the generation of cracks that bury the deposits can be suppressed and the deposits can be easily removed, so that the lubricant is not applied. There is an effect that it is possible to satisfactorily clean the attached matter such as toner on the surface and to prevent the attached matter such as toner from adhering to the surface.

According to the third, tenth, seventeenth, twenty-second, and twenty-third aspects of the present invention, even when the cleaning means is brought into contact with the transfer material support, the frictional force between the transfer material support and the cleaning means is reduced to a predetermined value or less. This has the effect of preventing the cleaning means from being turned up.

According to the inventions of claims 4, 11, 18, 22 and 23, when the transfer material carrier is used for supporting the transfer material, the occurrence of cracks such that the deposits are buried is surely suppressed. Since the adhering matter can be easily removed, the adhering matter such as toner on the surface can be favorably cleaned without applying a lubricant, and the adhering matter such as toner can be prevented from adhering to the surface. There is.

According to the inventions of claim 5, 12, 19, 22, and 23, when the transfer material carrier is used for supporting the transfer material, the frictional force between the transfer material carrier and the cleaning means is set to a predetermined value or less. There is an effect that the suppression can be surely suppressed and the cleaning means can be prevented from being turned up.

According to the sixth, thirteenth, twenty-second, and twenty-third aspects of the invention, there is an effect that the occurrence of the cracks can be surely prevented without the coating layer being abraded to a predetermined level or less even with time.

According to the seventh, fourteenth, twenty-first, twenty-second, and twenty-third aspects of the present invention, it is possible to suppress the occurrence of cracks in which the buried substance is buried, and to easily remove the buried substance. There is an effect that it is possible to satisfactorily clean the attached matter such as toner on the surface and to prevent the attached matter such as toner from adhering to the surface.

[Brief description of the drawings]

FIG. 1 is a graph showing an experimental result obtained by measuring a relationship between a crack generated on a transfer belt 6 and a cleaning property in Example 1.

FIG. 2 is a perspective view of a transfer device using a transfer belt according to the embodiment of the present invention.

FIG. 3 is a plan view showing a schematic configuration of the transfer device.

FIG. 4 is a schematic configuration diagram of an image forming apparatus using the transfer device.

FIG. 5 is a schematic configuration diagram of the image forming apparatus shown in FIG. 4 during a transfer operation.

FIG. 6 is a sectional view of a transfer belt used in the transfer device.

FIG. 7 is an explanatory diagram showing a transfer operation of toner particles in the transfer device.

FIG. 8 is a graph showing experimental results obtained by measuring the relationship between the elongation ratio at the time of occurrence of cracks in the transfer belt / the elongation ratio at the time of stretching and the front cleaning property in Example 2.

FIG. 9 is a graph showing an experimental result obtained by measuring the relationship between the extension ratio of the transfer belt at the time of occurrence of cracks / the extension ratio at the time of stretching and the turning (turning in) of the cleaning blade in Example 3.

FIG. 10 is a graph showing experimental results obtained by measuring the relationship between the thickness of the coating layer of the transfer belt and the elongation at the time of occurrence of cracks in Example 4.

FIG. 11 is an experimental result obtained by measuring the relationship between the thickness of the coating layer of the transfer belt, the surface roughness (ten-point average roughness) Rz of the belt in the axial direction, and the cleaning characteristics of the transfer belt surface in Example 4. A graph showing.

FIG. 12 is an experimental result obtained by measuring the relationship between the thickness of the coating layer of the transfer belt, the surface roughness (ten-point average roughness) Rz of the transfer belt in the circumferential direction, and the cleaning characteristics of the transfer belt surface in Example 1. A graph showing.

[Explanation of symbols]

 Reference Signs List 1 transfer device 2 belt unit 3 photoreceptor (image carrier) 4 driven roller 5 drive roller 6 transfer belt (transfer material carrier) 6a base layer 6b coating layer 11 bias roller 16 belt cleaning device 16A cleaning blade S transfer paper (transfer) Material)

Claims (23)

[Claims] 1. A belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the belt-like transfer material carrier has a surface on which the transfer material is carried when used for carrying the transfer material. A transfer material carrier, wherein a coating layer is provided on the surface such that the width of the generated cracks is equal to or smaller than the size of the deposit attached to the surface. 2. A belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the belt-like transfer material carrier is stretched until cracks are generated on the surface carrying the transfer material. A transfer material carrier, wherein a coating layer is provided on the surface so that the elongation is 8% or more. 3. The transfer material carrier according to claim 2, wherein the coating layer is provided so that the elongation rate when the surface supporting the transfer material is expanded until cracks are generated is 20% or less. A transfer material carrier, characterized in that: 4. A belt-like transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the belt-like transfer material carrier is stretched until cracks occur on the surface carrying the transfer material. A transfer material carrier, wherein a coating layer is provided on the surface such that the extension rate is at least twice the extension rate when used for supporting the transfer material. 5. The transfer material supporting member according to claim 4, wherein the expansion ratio when the transfer material is stretched until cracks are generated on the surface supporting the transfer material is the expansion ratio when the transfer material is used for supporting the transfer material. A transfer material carrier provided with the above-mentioned coating layer so as to be 5 times or less. 6. The transfer material carrier according to claim 1, wherein said coating layer has a thickness of 2 to 4 μm. 7. A belt-shaped transfer material carrier for carrying a transfer material onto which a toner image on an image carrier is transferred, wherein the surface carrying the transfer material has a ten-point average roughness Rz of 4Z or less. A transfer material carrier, characterized in that: 8. The transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and a transfer charge is applied to the transfer material carrier. A transfer method for transferring a toner image on the image carrier to the transfer material, wherein a crack generated on a surface supporting the transfer material when the transfer material carrier is used for carrying the transfer material. A method in which a coating layer is provided on the surface such that the width of the film is equal to or smaller than the size of the substance attached to the surface. 9. The transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and a transfer charge is applied to the transfer material carrier. A transfer method of transferring the toner image on the image carrier to the transfer material, wherein the transfer material carrier has an expansion rate when the surface supporting the transfer material is extended until cracks occur. A transfer method characterized by using a film provided with a coating layer on the surface so as to be 8% or more. 10. The transfer method according to claim 9, wherein the transfer material carrier has an expansion ratio of 20 when the transfer material is stretched until cracks occur on the surface supporting the transfer material.
%, Wherein a transfer layer provided with the above-mentioned coating layer is used. 11. The transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and a transfer charge is applied to the transfer material carrier. A transfer method of transferring the toner image on the image carrier to the transfer material, wherein the transfer material carrier has an expansion rate when the surface supporting the transfer material is extended until cracks occur. A transfer method wherein a coating layer is provided on the surface of the transfer material so as to have an elongation ratio of twice or more when used for supporting the transfer material. 12. The transfer method according to claim 11, wherein the transfer material supporting member has an extension rate when the transfer material is stretched until cracks are generated on a surface supporting the transfer material. A transfer method characterized by using a film provided with the above-mentioned coating layer so as to be 5 times or less the elongation rate at that time. 13. The transfer method according to claim 8, wherein said coating layer has a thickness of 2 to 4 μm. 14. The transfer material carrier is driven in one direction while the transfer material carried on the belt-shaped transfer material carrier is brought into contact with the image carrier, and a transfer charge is applied to the transfer material carrier. A transfer method for transferring a toner image on the image carrier to the transfer material, wherein the transfer material carrier has a ten-point average roughness Rz of 4Z or less on a surface supporting the transfer material. A transfer method characterized by using: 15. A belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and a transfer charge application device which applies a transfer charge by contacting the transfer material carrier. And a power supply for applying a transfer bias voltage to the transfer charge applying means, and a transfer device for transferring the toner image on the image carrier to the transfer material. When the stretched transfer material carrier is used to support the transfer material, the width of the cracks generated on the surface supporting the transfer material is set to be equal to or smaller than the size of the adhered material adhered to the surface. A transfer device using a device provided with a coating layer. 16. A belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and a transfer charge application device which applies a transfer charge by contacting the transfer material carrier. And a power supply for applying a transfer bias voltage to the transfer charge applying means, and a transfer device for transferring the toner image on the image carrier to the transfer material. A transfer device comprising a film layer provided on the surface so that the elongation is 8% or more when the film is stretched until a crack is generated on the surface carrying the film. 17. The transfer device according to claim 16, wherein the transfer material carrier has an expansion ratio of 20 when the transfer material is stretched until cracks are generated on the surface supporting the transfer material.
%, Wherein a transfer layer provided with the above-mentioned coating layer is used. 18. A belt-like transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and a transfer charge applying device which applies a transfer charge by contacting the transfer material carrier. And a power supply for applying a transfer bias voltage to the transfer charge applying means, and a transfer device for transferring the toner image on the image carrier to the transfer material. So that the extension rate when the sheet is stretched until cracks are generated on the surface carrying the transfer material becomes twice or more the extension rate when the transfer material carrier is used to support the transfer material by being stretched on the support member. A transfer device using a surface provided with a coating layer. 19. The transfer device according to claim 18, wherein the transfer material supporting member has a stretching ratio when stretched until a crack is generated on a surface supporting the transfer material, and the transfer material is stretched over a supporting member to transfer the material. A transfer apparatus using a material provided with the above-mentioned coating layer so as to have an elongation ratio of 5 times or less when a material carrier is used for supporting a transfer material. 20. The transfer device according to claim 15, wherein said coating layer has a thickness of 2 to 4 μm. 21. A belt-shaped transfer material carrier which is driven in one direction while sandwiching the transfer material between the image carrier and a transfer charge application device which applies a transfer charge by contacting the transfer material support material. And a power supply for applying a transfer bias voltage to the transfer charge applying means, and a transfer device for transferring the toner image on the image carrier to the transfer material. A surface having a ten-point average roughness Rz of 4Z or less is used. 22. A latent image forming means for forming a latent image on a latent image carrier as an image carrier, a developing means for developing the latent image on the latent image carrier with toner, and the latent image carrier And a transfer device for transferring the upper toner image onto a transfer material on a transfer material carrier, wherein the transfer device according to any one of claims 15 to 21 is used as the transfer device. An image forming apparatus comprising: 23. A latent image forming means for forming a latent image on a latent image carrier, a developing means for developing the latent image on the latent image carrier with toner, and a toner image on the latent image carrier. An image forming apparatus comprising: transfer means for transferring an intermediate transfer member as an image carrier; and a transfer device for transferring a toner image on the intermediate transfer member to a transfer material on a transfer material carrier. An image forming apparatus using the transfer device according to any one of claims 15 to 21 as an apparatus.