JP2003122136A - Transfer device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer device having a structure that prevents displacement in image transfer, thereby preventing occurrence of an image defect such as color slippage. SOLUTION: The transfer device composed so that images of different colors, rendered visible on corresponding latent image carriers 3, are sequentially transferred to a transfer body using a single belt 2 that passes through the latent image carriers 3, is characterized in that the belt 2 is stretched over at least a pair of rollers 2A and 2B, and provided with a drive roller 14 and an opposite roller 15 which face each other with an uncurved flat portion of the belt 2 between them as separate power sources and in which the drive roller 14 serves as a drive source separate from the rollers 2A and 2B and the opposite roller 15 serves as a followable pressing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device and an image forming apparatus, and more particularly to a transfer position shift prevention structure for superposing and transferring an image using a belt-shaped transfer member.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, or a printing machine, a visible image carried on a photoconductor which is a latent image carrier is transferred to a transfer body. There is. As the transfer member, a belt-shaped transfer member may be used in addition to a recording sheet which directly contacts and abuts the photosensitive member. One of the latter cases is multicolor image formation including full color. As a configuration for forming a multicolor image, a case where one photoconductor that is a latent image carrier is used to form an electrostatic latent image for each color separation color, and a case where a plurality of photoconductors are used for each photoconductor In some cases, an electrostatic latent image corresponding to the color separation color is formed. When using one photoconductor,
A developing device capable of supplying a toner of a color complementary to the color separation formed by the writing device with a charging device, a writing device, and a transfer device is provided for the photoconductor according to the number of color separations. The toner image is formed by supplying toner from a developing device of a color corresponding to the electrostatic latent image formed on the photoconductor to form a synthetic toner image on the photoconductor. Above, the process of transferring the synthetic toner image to the recording sheet is adopted. When a plurality of photoconductors are used, an image forming unit is configured to include an apparatus that performs an image forming process for each photoconductor, that is, an apparatus that executes each process of charging, writing, and developing. The toner images formed in step 1 are sequentially transferred onto the intermediate transfer body and then transferred collectively to the recording sheet, or the recording sheet is conveyed to the position of each image forming unit and directly superposed on the recording sheet during the conveying process. A transfer process is adopted.

When one of the photoconductors mentioned above is used, the number of photoconductors is small, so that the size of the apparatus can be reduced. On the other hand, one photoconductor is used as a target, and a static color corresponding to each color separation is used. There is a problem that it takes a long time to obtain a multicolor image because the process of forming a latent image is repeated. On the other hand, in the case of using a plurality of image forming units mentioned in the latter, there is an advantage that the image forming processing can be speeded up because the image forming processing can be performed in parallel in each image forming unit.

On the other hand, as a configuration in the case of using a plurality of image forming units mentioned in the latter, there are configurations shown in FIGS. 3 and 4. The configurations shown in FIGS. 3 and 4 are different in the transfer method of the image formed in the image forming unit. In the configuration shown in FIG. 3, the image forming units A1 to A4 and the photosensitive units in the image forming units A1 to A4 are different. A toner image formed by each image forming unit is directly applied to a recording sheet S (for convenience, indicated by an arrow indicating a moving direction) electrostatically attracted to a conveying belt C that is movable opposite to the bodies B1 to B4. By being transferred, the toner images of the respective colors are superimposed and transferred onto the recording sheet S.

In the configuration shown in FIG. 4, each image forming unit A1
To toner images of the respective colors formed by A4 to the image forming units A
1 to A4 are superimposed and transferred onto the intermediate transfer belt D as an intermediate transfer member facing the photoconductors B1 to B4, and the synthetic toner images carried on the intermediate transfer belt D are collectively transferred onto the recording sheet S. In the transfer method used in the configuration shown in FIG. 4, the transfer to the intermediate transfer member is often called the primary transfer, and the transfer to the recording sheet is often called the secondary transfer.

As shown in FIG. 4, when the intermediate transfer belt D is used as an intermediate transfer member, a structure including a driving roller D1, a driven roller D2 and a tension roller D3 arranged between these rollers is used. Transfer members E1 to E2 for transferring a visible image formed on each of the image forming units A1 to A4 are provided at positions that are used and face the photoconductors B1 to B4 in each of the image forming units A1 to A4. Has been. In addition, in FIG. 3 and FIG.
Indicates a discharge conveyance belt, and reference numeral G indicates a fixing device.

[0007]

When a conveyor belt or a belt is used as an intermediate transfer member as a member used for transferring a toner image formed on a photoreceptor in an image forming unit, images are transferred to each other. It is important to align the transfer positions of the above in order to prevent the occurrence of color unevenness in the image.

Particularly, in the case of a structure called a tandem system in which the image forming units are arranged side by side in the belt extending direction as in the structure shown in FIG. 4, the belt is stretched and the rollers around which the belt is stretched are stretched. The moving state of the belt is apt to change due to eccentricity, etc., which may cause the transfer positions of the image forming units to shift from each other.

In order to align the transfer position in each image forming unit with the image transfer position on the belt, for example, the distance (P1) between the image transfer positions indicated by the symbol P in FIG.
A roller located on the driving side of the belt (reference numeral D1 in FIG. 4).
It is conceivable to set it as an integral multiple of the roller) circumference. As a result, even if the roller is eccentric, the phase of the one-rotational-cycle speed fluctuation of the roller is the same at each transfer position, and it is possible to make a state in which there is almost no positional deviation of the image. In other words, the speed fluctuation phase of the transfer body at the image transfer position of the first color is the same at the image transfer positions of the second and subsequent colors, so that the speed fluctuations at the image transfer positions are the same. It is possible to eliminate the expansion and contraction of the transfer member due to the difference in speed at each image transfer position.

However, the above-mentioned conditions are based on the assumption that the belt has a uniform thickness, and when the thicknesses are different, even if this condition is set, the belt is wound around the roller. The peripheral speed changes, which changes the moving speed of the belt, and as a result, the image transfer position of the belt may deviate from the transfer position of each image forming unit.

5 to 7 are diagrams for explaining the reason why the above-mentioned phenomenon occurs. In FIG. 5, it is difficult to set the thickness of the belt D used to a uniform thickness in terms of processing accuracy, and the thickness varies (ta> tb). When the thickness varies, the moving speed of the belt on the drive roller D1 differs as shown in FIGS. 6 and 7. That is, in the case shown in FIG. 6, a portion having a larger thickness than the other portions is wound around the drive roller D1, and thus the peripheral speed at this time is the drive roller D around which the belt is wound.
6 is obtained as a product of the radius and the angular velocity (ω), which is obtained by adding the radius average of 1 to the radius (R) of 1 to the belt-side thickness average based on 1/2 to 1/3 of the belt thickness. And the peripheral speeds (Va, Vb) in the case shown in FIG. Va = {roller radius (R) + belt thickness (ta / 2)} × ω ·· (1) Vb = {roller radius (R) + belt thickness (tb / 2)} × ω · (2) where Since the thickness is ta> tb, the peripheral speed (Va, Vb) is Va> Vb. from this result,
Due to the difference in thickness, the stretched portion of the belt in accordance with the change in the moving speed of the drive roller D1 when rotating,
That is, the moving speed of the portion reaching the transfer position changes.

In order to eliminate the change in the belt moving speed, it is necessary to eliminate the difference in thickness.
The present situation is that variations inevitably occur during processing, and it is currently difficult to match the image transfer position on the belt with the transfer position in each image forming unit. For this reason, even if the dimensional accuracy of the driving roller and the elongation of the belt are suppressed, it is possible that the transfer positions do not coincide with each other and color shift may occur due to the inability to suppress the speed variation due to the thickness variation.

In view of the problems when the above-mentioned conventional transfer device, particularly a belt is used, an object of the present invention is to provide a structure capable of preventing the transfer position of the image from being displaced and preventing the occurrence of a defective image such as color shift. An object of the present invention is to provide a transfer device and an image forming apparatus provided with the transfer device.

[0014]

The invention according to claim 1 is
A transfer device having a configuration in which images of different colors that have been subjected to visible image processing on a plurality of latent image carriers are sequentially transferred to a transfer member that uses a single belt that passes through the positions of the latent image carriers. In the above, the belt is characterized in that it is wound around at least one pair of rollers and is driven by a drive source different from the rollers.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the drive source forms a drive roller and a followable pressurizing means which face each other with a flat surface portion of the belt interposed therebetween. It is characterized in that it has an opposed roller.

The invention according to claim 3 is the invention according to claim 1 or 2.
In addition to the above-mentioned invention, the arrangement position of the drive source is set to the upstream side in the moving direction of the belt with respect to the transfer position of the image on the plane portion of the belt.

According to a fourth aspect of the present invention, in addition to the second aspect, the circumference of the drive roller in the drive source is
It is characterized in that it is set to 1 / (n), which is an integer of the arrangement interval of each latent image carrier.

According to a fifth aspect of the present invention, in addition to the second aspect of the invention, the diameter of the facing roller is set to be a fraction of the diameter of the driving roller (1 / n). It is characterized by being.

According to a sixth aspect of the invention, the transfer device according to any one of the first to fifth aspects is used in an image forming apparatus.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of an image forming apparatus to which a transfer device according to an embodiment of the present invention is applied. The image forming apparatus shown in FIG. 1 is a latent image carrier capable of forming an image of a color corresponding to color separation. It has a tandem system configuration in which multiple photoconductors are arranged side by side, and the toner images formed on each photoconductor are superposed and transferred onto an intermediate transfer body, and then the superposed images are collectively transferred to a sheet such as recording paper. By doing so, the color printer can form a multicolor image. In the present invention, the image forming apparatus is not limited to a color printer, but it goes without saying that a color copying machine, a facsimile machine, a printing machine and the like are included.

In FIG. 1, the color printer 1 has an image forming unit 1A located at the central portion in the vertical direction, a paper feeding unit 1B below the image forming unit 1A, and a document table 1C1 above the image forming unit 1A. The document scanning units 1C provided are arranged respectively. An intermediate transfer belt 2 having a horizontally extending surface is arranged in the image forming portion 1A.
A structure for forming an image of a color that has a complementary color relationship with the color separation color is provided above.

In the image forming section 1A, photoconductors 3B, 3Y, 3C and 3M capable of carrying images of toners of colors complementary to each other (yellow, magenta, cyan and black) are formed on the spreading surface of the intermediate transfer body 2. Are juxtaposed along. In the following description, when the content is common to all the photoconductors, the photoconductor is denoted by reference numeral 3. Each photoconductor 3B, 3Y,
Each of 3C and 3M is composed of a drum that can rotate in the same direction (counterclockwise in FIG. 1), and a charging device 4, a writing device 5, and the like that perform image forming processing in the rotation process around the drum. A developing device 6, a primary transfer device 7, and a cleaning device 8 are arranged (for the sake of convenience, reference is made to the photoconductor 3B by adding B to the reference numeral of each device).

The intermediate transfer belt 2 corresponds to a primary transfer portion to which a visible image from an image forming unit including each photoconductor is sequentially transferred, and is wound around a plurality of rollers 2A to 2C to be exposed. The roller 2C, which is movable in the same direction at the position facing the body and is different from the rollers 2A and 2B forming the spreading surface, faces the secondary transfer device 9 with the intermediate transfer belt 2 interposed therebetween. . In FIG. 1, reference numeral 10 indicates a cleaning device for the intermediate transfer belt 2.

The secondary transfer device 9 is a transfer belt 9C which is movable in the same direction as the intermediate transfer belt 2 at the secondary transfer position where the secondary transfer device 9 is positioned by being wound around the charging drive roller 9A and the driven roller 9B. The transfer belt 9C is charged by the charging drive roller 9A to convey the recording sheet while electrostatically adsorbing the recording sheet, and the multicolor image superimposed on the intermediate transfer belt 2 is collectively transferred or carried. Each single color image can be transferred to a recording sheet.

The recording sheet is fed from the sheet feeding section 1B to the secondary transfer position. The sheet feeding unit 1B includes a plurality of sheet feeding cassettes 1B1, a plurality of conveying rollers 1B2 arranged in a conveying path for recording sheets fed from the sheet feeding cassette 1B1, and a registration roller 1B3 located in front of the secondary transfer position. I have it. In this embodiment, the paper feeding unit 1B
In addition to the conveyance path of the recording sheet fed from the sheet feeding tray 1B1, the recording sheet 1B1 is provided with a configuration capable of feeding a recording sheet of a type not stored in the sheet feeding cassette 1B1 toward the secondary transfer position. The configuration includes a manual feed tray 1A1 in which a part of the wall surface of the image forming unit 1A is provided so as to be erected and a feeding roller 1A2. In the middle of the recording sheet conveyance path from the paper feed cassette 1B1 to the registration rollers 1B3, the conveyance paths of the recording sheets fed from the manual feed tray 1A1 merge, and the recording sheets fed from either conveyance path are also registered by the registration rollers. The registration timing is set by 1B3. The registration roller 1B3 is usually grounded and used in many cases, but a bias for removing paper dust may be applied for the purpose of removing paper dust on the recording sheet.

The writing device 5 (indicated by reference numeral 5B in FIG. 1 for the sake of convenience) outputs image information obtained by scanning an original on the original table 1C1 included in the original scanning unit 1C or a computer (not shown). The writing light is controlled by the image information to be generated, and the photoconductors 3B, 3
An electrostatic latent image corresponding to image information is formed on Y, 3C, and 3M.

The original scanning unit 1C is provided with a scanner 1C2 for exposing and scanning the original on the original placing table 1C1, and an automatic original feeding device 1C3 is arranged on the upper surface of the original placing table 1C1. . Automatic document feeder 1C3
Has a structure capable of reversing an original fed out on the original placing table 1C1 so that the front and back surfaces of the original can be scanned.

Photoreceptor 3 formed by writing device 5
The electrostatic latent image on (members indicated by reference numerals 3B, 3Y, 3C, and 3M in FIG. 1) is a developing device 6 (in FIG. 1, for convenience,
The image is subjected to a visible image processing (shown by reference numeral 6B) and is primarily transferred to the intermediate transfer belt 2. When the toner images of the respective colors are superimposed and transferred onto the intermediate transfer belt 2, the secondary transfer device 9 collectively and secondarily transfers the toner images onto the recording sheet.

An unfixed image carried on the surface of the secondary-transferred recording sheet is fixed by the fixing device 11. Although not shown in detail, the fixing device 11 has a belt fixing structure including a fixing belt heated by a heating roller and a pressure roller facing and abutting against the fixing belt. By providing the area, that is, the nip area, the heating area for the recording sheet can be expanded as compared with the fixing structure of another roller type. The recording sheet that has passed through the fixing device 11 is configured such that the conveying direction can be switched by the conveying path switching claw 12 arranged at the rear of the fixing device 11, and the conveying path toward the sheet discharge tray 13 and the reverse conveyance can be performed. The transport direction is selected for the route RP.

The intermediate transfer belt 2 prepares for the primary transfer again after the residual toner is removed by the cleaning device 10 after collectively transferring the superimposed and transferred images.

In the color printer 1 having the above-described structure, the photoconductor 3 uniformly charged by exposing and scanning the document placed on the document table 1C1 or by the image information from the computer. On the other hand, an electrostatic latent image is formed, the electrostatic latent image is subjected to a visible image processing by the developing device 6, and then the toner image is primarily transferred onto the intermediate transfer belt 2.

The toner image transferred to the intermediate transfer belt 2 is directly transferred to the recording sheet fed from the paper feeding unit 1B in the case of a single color image, and is primarily transferred in the case of a multicolor image. By being repeated, they are superimposed and then secondarily transferred to the recording sheet at once. After the secondary transfer, the recording sheet has the unfixed image fixed by the fixing device 11, and then the recording sheet is fed to the discharge tray 13 or inverted and fed again to the registration roller 1B3.

The intermediate transfer belt 2 forming the primary transfer portion and its driving structure are shown in FIG. In FIG.
Although not shown in detail, the intermediate transfer belt 2 is provided on the upper surface of a base layer composed of a base portion composed of a fluororesin having a small elongation or a rubber material having a large elongation and made of a material such as canvas which does not easily expand. And an elastic body layer using a fluorine-based rubber, an acrylonitrile-butadiene copolymer rubber, or the like. The surface of the elastic layer is coated with a fluororesin to provide a coat layer having improved smoothness.

The intermediate transfer belt 2 is wound around at least a pair of supporting rollers 2A and 2B and a roller 2C having a backup function, and is driven by the counterclockwise rotation of the driving roller 2A. There is. The surface extended between the support rollers 2A and 2B, that is, the flat surface without curvature is the photoconductor 3 of each image forming unit.
It faces B, 3Y, 3C, and 3M. Transfer rollers 2D for electrostatically transferring a visible image on the photoconductor are arranged at positions facing the photoconductors with the intermediate transfer belt 2 interposed therebetween.

The intermediate transfer belt 2 includes support rollers 1A and 2
It is adapted to be driven by a drive source provided separately from B and 2C. The configuration will be described below with reference to FIG. The drive source is opposed to the drive roller 14 with the drive roller 14 and the drive roller 14 disposed on a flat surface portion having no curvature upstream of the image transfer position for each image forming unit in the moving direction of the intermediate transfer belt 2 in between. The drive roller 14 is driven to rotate by the drive motor 16 to drive the intermediate transfer belt 2.

The opposing roller 15 is an elastic body 17 such as a spring.
The habit of pressing the intermediate transfer belt 2 against the drive roller 14 side is given by. Therefore, the intermediate transfer belt 2 is driven by being nipped by the driving roller 14 and the opposing roller 15 and by utilizing the frictional force between the intermediate transfer belt 2 and the driving roller 14, the rotational force is satisfactorily transmitted. ing.

The drive roller 14 and the counter roller 15 are
The configuration is subject to the following conditions.

(1) The drive roller 14 is the drive roller 14
Is set to a peripheral length that is a fraction (1 / n) of the arrangement interval P1 between the image transfer positions where the photoconductor 3 and the intermediate transfer belt 2 in each image forming unit face each other. . (2) The opposing roller 15 is set to have a diameter that is 1 / n of the integer of the diameter of the driving roller 14. According to the condition described in (1), even when the drive roller 14 has eccentricity or speed unevenness, the cycle of occurrence of eccentricity or speed unevenness can be matched between image transfer positions in the image forming unit. . That is, if the cycle of the speed fluctuation caused by the difference in the thickness of the intermediate transfer belt 2 is the same at each image transfer position, the speed deviation at each image transfer position can be eliminated. The speed change at the time when the image transfer position is reached can be matched between the image transfer positions, and the shift of the image transfer position can be prevented. As a result, it is possible to eliminate the color shift due to the shift of the image transfer position.

According to the condition mentioned in (2), even when the periodical speed fluctuation of the opposed roller 15 occurs, the image transfer positions can be matched with each other in the same cycle.
It is possible to release the color shift by eliminating the shift of the image transfer position caused by the shift of the speed fluctuation between the image transfer positions.

Since the embodiment of the present invention is configured as described above, since the driving is performed on the flat surface portion of the intermediate transfer belt 2 which has no curvature, even if the intermediate transfer belt 2 has a different thickness, the supporting roller is supported. Unlike the case of driving in 2A, 2B, and 2C, the peripheral speed difference on the roller peripheral surface does not occur. As a result, it is possible to prevent the speed fluctuations from being inconsistent between the image transfer positions, and thus it is possible to prevent the occurrence of color misregistration due to the image transfer position deviation.

On the other hand, regarding the speed fluctuation of the intermediate transfer belt 2 at each image transfer position, since the circumferential length of the driving roller 14 of the intermediate transfer belt 2 is the condition given in (1), the intermediate transfer belt 2 is described. If the cycle of the speed fluctuation caused by the difference in thickness existing in 2 is the same at each image transfer position, the speed deviation at each image transfer position can be eliminated. As a result, the speed change at the time when the intermediate transfer belt 2 reaches each image transfer position can be made to coincide between the image transfer positions, and the shift of the image transfer position can be prevented.
It is possible to eliminate the color shift due to the shift of the image transfer position.

Regarding the speed fluctuation of the intermediate transfer belt 2,
Since the diameter of the opposing roller 15 that nip-drives the intermediate transfer belt 2 in cooperation with the driving roller 14 is set to the condition given in (2), even if the periodic velocity fluctuation of the opposing roller 15 occurs, Since the image transfer positions can be matched with each other in the same cycle, there is no deviation in the speed fluctuation between the image transfer positions, and it is possible to eliminate the deviation in the image transfer positions and release the color misregistration. .

[0043]

According to the first aspect of the present invention, since the drive source is provided in addition to the roller around which the belt is wound, the difference in peripheral speed is caused by the difference in the thickness of the belt around which the belt is wound. There is no occurrence. Therefore, since the movement speed of the belt does not change due to the difference in peripheral speed, the image transfer position on the belt side with respect to the transfer position with each latent image carrier is not displaced,
It is possible to prevent the occurrence of color shift.

According to the second aspect of the present invention, since the belt having no curvature, that is, the flat roller is provided with the driving roller and the opposing roller that can be nipped and driven, the peripheral speed is different from the case where the belt is wound. Does not change.

According to the third aspect of the present invention, since the arrangement position of the drive source is set on the upstream side of the transfer position in the moving direction of the belt, the belt is maintained with a speed difference before transfer. It is possible to prevent the above-mentioned image transfer position from being displaced and to reliably prevent the color misregistration from occurring.

According to the fourth aspect of the invention, since the peripheral length of the drive roller is set to 1 / (n), which is an integer of the arrangement interval between the latent image carriers, the drive roller is eccentric. Even when the angular velocity fluctuation occurs, the rotation cycle due to the eccentricity or the velocity fluctuation can be matched at each image transfer position. As a result, the speed fluctuations of the transfer body at the image transfer position of the first color occur at the same cycle at the image transfer positions of the second and subsequent colors, so that the speed fluctuations at the image transfer positions become the same. It is possible to eliminate the deviation of the image transfer position on the belt side due to the variation which is different at each image transfer position. As a result, the moving speed of the belt at the image transfer position becomes the same as the previous moving speed, and the speed deviation is prevented from occurring, and the color misregistration due to the speed difference at the image transfer position can be reliably eliminated. It will be possible.

According to the fifth aspect of the invention, since the diameter of the opposing roller is set to 1 / (n), which is an integer of the circumferential length of the driving roller, periodical velocity fluctuations of the opposing roller occur. Even if the image transfer positions are the same, the image transfer positions can be matched with each other in the same cycle. Therefore, there is no deviation in the speed variation between the image transfer positions, and the deviation in the image transfer positions due to this does not occur and the color misregistration is released. It becomes possible.

According to the sixth aspect of the present invention, since the change in the moving speed of the belt when the belt is used can be matched at each image transfer position, the image transfer due to the different speed fluctuations at each image transfer position. It is possible to obtain an image without color shift by eliminating the positional shift.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus including a transfer device according to an embodiment of the present invention.

FIG. 2 is a partial enlarged view for explaining the configuration of the transfer device according to the embodiment of the present invention.

FIG. 3 is a schematic view showing an example of a multicolor image forming apparatus equipped with a transfer device using a belt.

FIG. 4 is a schematic view showing another example of a multicolor image forming apparatus equipped with a transfer device using a belt.

FIG. 5 is a schematic diagram showing a configuration of an apparatus using a belt.

FIG. 6 is a schematic diagram for explaining a peripheral speed based on a dimensional relationship between a belt thickness and a roller around which the belt is wound.

FIG. 7 is a schematic diagram for explaining the peripheral speed when the thickness of the belt shown in FIG. 6 is different from that in FIG.

[Explanation of symbols]

1 Laser Printer 1A as an Example of Image Forming Apparatus 2 Image Forming Section 2 Intermediate Transfer Belt 2A Located at Primary Transfer Section 2A Intermediate Transfer Belt Drive Roller 2B Intermediate Transfer Belt Driven Roller 3 Photoconductor 9 2 which is a latent image carrier Secondary transfer device 9A Charging roller 14 for secondary transfer 14 Drive roller 15 which is one component of belt drive source Opposing roller 16 which is another component of belt drive source Drive motor P1 Each latent image carrier and intermediate transfer belt Arrangement interval between image transfer positions facing each other

Continued front page    F term (reference) 2H030 AA01 AA07 AB02 BB42 BB44                       BB46                 2H200 FA04 FA17 GA23 GA44 GA47                       GB25 JB06 JB10 JB32 JC04                       JC07 JC12 JC13 JC15 LA12                       LA14 LA15 LA17 LB02 LB09                       LB13 MA04 MA20

Claims (6)

[Claims] 1. A structure in which images of different colors that have been subjected to visible image processing on a plurality of latent image carriers are sequentially transferred to a transfer member using a single belt that passes through the positions of the latent image carriers. In the transfer device, the belt is wound around at least a pair of rollers,
A transfer device comprising a structure driven by a drive source different from the roller. 2. The transfer device according to claim 1, wherein the drive source includes a drive roller facing each other with a flat surface portion of the belt sandwiched therebetween and a facing roller forming a followable pressurizing unit. Transfer device characterized by. 3. The transfer device according to claim 1, wherein the drive source is arranged at a position upstream of a transfer position of the image on the flat surface of the belt in the moving direction of the belt. Transfer device characterized by. 4. The transfer device according to claim 2, wherein the peripheral length of the drive roller in the drive source is set to an integer fraction (1 / n) of the arrangement interval of the latent image carriers. Transfer device characterized by. 5. The transfer device according to claim 2, wherein the diameter of the facing roller is set to be approximately one integer (1 / n) with respect to the diameter of the driving roller. apparatus. 6. An image forming apparatus using the transfer device according to any one of claims 1 to 5.