JP2003091131A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of obtaining a good image without needing any alternation of an image forming condition while securing good fixation irrespective of the kind of recording materials. SOLUTION: The image forming apparatus is provided with a plurality of image carriers 102 (Y, M, C and BK) for forming toner images, a plurality of primary transfer parts 40 (Y, M, C and BK) arranged side by side so as to successively transfer the images formed on respective image carriers to an intermediate transfer body 301, a secondary transfer part 50 for transferring the image transferred to the intermediate transfer body 301 to a recording material 151, and a fixing part 60 for fixing the transferred image on the recording material. When a distance between the secondary transfer part 50 and the fixing part 40BK is Lf, and the maximum length of the recording material 151 in the carrying direction is Lp, Lf>Lp is satisfied.

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, various printers, a facsimile, a scanner having a print function, and a composite machine of these, and more particularly to an intermediate transfer for receiving an image from an image carrier. The present invention relates to an image forming apparatus having a body.

[0002]

2. Description of the Related Art Image forming apparatuses are classified into a 4-cycle type using a single photoconductor as an image carrier and a tandem type using a plurality of photoconductors. While the former can reduce the size of the device, the number of color outputs per unit time is small, while the latter increases the number of outputs, but it is difficult to downsize the device and align each color. The image forming apparatus includes a direct transfer type in which an image is directly transferred to a recording material as a final transfer member, and an intermediate transfer type in which an image is transferred to an intermediate transfer body and then the image is transferred from the intermediate transfer body to the recording material. is there. In the intermediate transfer method, when the image is transferred from the image carrier, since the material of the intermediate transfer body is constant, the alignment of each color is preferable as compared with the direct transfer method, and a high quality image with less color misregistration can be obtained. It has the feature.

In image forming apparatuses of various transfer systems as described above, an image transferred onto a recording material is conveyed to a fixing unit and passed through a fixing unit of the fixing unit, so that the transferred image is exposed to heat and pressure. It is fixed on the recording material by the action. Various types of recording materials are used, such as plain paper, thick paper or thin paper that is thicker than this, and thin resin sheet materials such as OHP sheets. Depending on the thickness and material of the paper, the fixability of the image can be improved. There are variations. Therefore, when the paper is thick paper, OHP sheet, or the like, good fixing property cannot be obtained unless heat is applied more than plain paper. It is slower than when using thin paper.

[0004]

In the image forming apparatus adopting the intermediate transfer method, the distance between the primary transfer portion for transferring to the intermediate transfer member and the secondary transfer portion for transferring to the recording material is in the conveying direction of the recording material. If the length is smaller than the total length, there is a period in which the primary transfer to the intermediate transfer member and the secondary transfer to the recording material are simultaneously performed. For this reason, it is necessary to make the linear velocity during movement of the intermediate transfer member and the conveying velocity of the recording material the same, and inevitably also the linear velocity of the image carrier and image forming conditions such as charging, writing and recording, and developing. , Which will correspond to these linear velocities. This means that image forming conditions corresponding to a plurality of linear velocities are required depending on the type of recording material, and a great deal of labor and problems must be overcome. Further, when the distance between the secondary transfer portion and the fixing portion is shorter than the entire length of the recording material, the recording material loosens and contacts the intermediate transfer body during this period, or the recording material buckles to obtain a good image. I can't. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of obtaining a good image without needing to change the image forming conditions while ensuring good fixing property regardless of the type of recording material.

[0005]

In order to achieve the above object, a plurality of image carriers on which toner images are formed, wherein a plurality of toner images are superposed to obtain a color image, and an image is formed. A plurality of primary transfer portions arranged in parallel for sequentially transferring the image formed on the carrier to the intermediate transfer body, a secondary transfer portion for transferring the image transferred on the intermediate transfer body to the recording material, and In an image forming apparatus having a fixing unit that fixes the transferred image on the recording material, when the distance between the secondary transfer unit and the fixing unit is Lf and the maximum length of the recording material in the transport direction is Lp, Lf > Lp. When the relationship between the distance Lf between the secondary transfer portion and the fixing portion and the maximum length Lp of the recording material in the conveying direction is Lf> Lp as in the present invention, when the secondary transfer onto the recording material is completed. Moreover, since the leading edge of the recording material does not reach the fixing portion, slack or buckling does not occur even if the conveying speed of the recording material changes.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the primary transfer portion and the secondary transfer portion, which are arranged near the secondary transfer portion of the plurality of primary transfer portions, are provided. When the distance is Lb, Lf>Lp> Lb. As in the present invention, the distance Lb between the secondary transfer portion and the primary transfer portion located near the secondary transfer portion among the plurality of primary transfer portions is
When the distance Lf between the secondary transfer portion and the fixing portion or the maximum length Lp of the recording material in the conveying direction is made shorter than the distance Lf, the first transfer portion and the second transfer portion simultaneously perform the primary transfer and the secondary transfer. Even if it occurs, since the leading edge of the recording material does not reach the fixing portion when the secondary transfer to the recording material is completed, slack or buckling does not occur even if the conveying speed of the recording material changes.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, there are provided driving means for rotationally driving the image carrier and the intermediate transfer body, and conveying means for conveying the recording material to the fixing section. And the linear velocity of the outer peripheral surface of each image carrier is V
d, where Vb is the linear velocity of the surface of the intermediate transfer member and Vp is the transport velocity of the recording material, Vd = Vb and Vp = Vb or Vp ≠ Vb can be changed. According to the present invention, even if the conveying speed Vp of the recording material is switched, the distance Lb between the secondary transfer portion and the fixing portion is longer than the maximum length Lp in the conveying direction of the recording material, so that the secondary transfer portion and the fixing portion are fixed. There is no slack or buckling of the recording material between the parts.

According to a fourth aspect of the invention, in the image forming apparatus according to the third aspect, there is provided switching means for switching the speed from Vp = Vb to Vp ≠ Vb when the image transfer from the intermediate transfer member to the recording material is completed. Have According to the invention,
When the image transfer from the intermediate transfer body to the recording material is completed, the switching means switches the relative speed between the linear velocity of the surface of the intermediate transfer body and the transport speed of the transport means so that Vp = Vb to Vp ≠ Vb. To be

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The image forming apparatus shown in FIG.
It is an electrophotographic type that obtains a color image by superposing a plurality of toner images. This image forming apparatus is yellow,
Four image forming units 101Y, 101M and 101 for forming magenta, cyan and black toner images, respectively.
A tandem type in which C and 101BK are continuously arranged in parallel, and an intermediate transfer unit 300 having an endless intermediate transfer belt 301 as an intermediate transfer member is provided. Is being promoted.

Image forming units 101Y, 101M, 1
01C and 101BK are drum-shaped photoconductors 102Y, 102M and 10 as an image carrier on which a toner image is formed.
It is equipped with 2C and 102BK. A belt-shaped photoreceptor may be used as the image carrier. Image forming unit 101Y,
101M, 101C, 101BK are the photoconductors 102Y,
Charging means 10 for uniformly charging the outer peripheral surface of each photoconductor around 102M, 102C and 102BK.
3Y, 103M, 103C, 103BK, and optical writing means 110Y, 110 for forming an electrostatic latent image on each photoconductor.
M, 110C, 110BK, and a developing device 104 that develops the formed electrostatic latent image to form a toner image of each color.
Y, 104M, 104C and 104BK, and cleaning means 106Y, 106M, 106C and 106BK for collecting and containing the residual toner remaining on each photoconductor. The outer peripheral surface of each photoconductor is rotationally driven counterclockwise in the present embodiment by the drive motor 120 at the linear velocity Vd. Each of the photoconductors may be rotationally driven by an individual motor instead of one motor.

The intermediate transfer unit 300 includes a photoconductor 102.
It is arranged below Y, 102M, 102C, and 102BK. The intermediate transfer unit 300 includes an intermediate transfer belt 301 having a medium resistivity to which toner images of respective colors are transferred,
Transfer brushes 105Y, 105 as primary transfer means for sequentially transferring the toner images on the photoconductors 102Y, 102M, 102C, 102BK onto the intermediate transfer belt 301.
M, 105C and 105BK, and a pair of transfer rollers 304 and 305 as a secondary transfer unit that constitutes a secondary transfer unit 50 that collectively transfers the toner images transferred onto the intermediate transfer belt 301 onto the recording material 151. ing.

The intermediate transfer belt 301 is stretched around a belt driving roller 302, a driven roller 303, and a transfer roller 304 to form a photosensitive member 102Y, 102M, 102C, 102.
It is arranged close to BK. The belt drive roller 302 is rotationally driven in the clockwise direction by the drive motor 120. The surface 301a of the intermediate transfer belt 301 is moved at a linear velocity Vb by the belt driving roller 302 being rotationally driven. The belt driving roller 302 may be rotated by a motor separate from the driving motor 120.

Inside the intermediate transfer belt 301, as shown in FIG. 2, the surface 301a of the intermediate transfer belt 301 is brought into contact with the outer peripheral surfaces of the respective photoconductors, and the primary transfer portions 40Y, 40Y.
Rotation assisting roller 30 forming M, 40C, 40BK
A plurality of 6,307 are provided. Each primary transfer portion is a contact area between the surface 301a and the outer peripheral surface of each photoconductor. In FIG. 2, only the rotation assisting rollers 306 and 307 arranged near the image forming unit 101BK are shown. The rotation assisting roller 306 is used for the intermediate transfer belt 3 in each primary transfer portion.
01 is arranged on the upstream side in the moving direction of the rotation assist roller 3
07 is arranged on the downstream side in the moving direction of the intermediate transfer belt 301 in each primary transfer portion. The recording material 15 that has passed through the secondary fixing unit 50 is provided on the downstream side in the vicinity of the secondary fixing unit 50.
A sensor 160 for detecting the rear end of the first unit is arranged.

As shown in FIG. 1, the intermediate transfer belt 301.
A fixing unit 107 having a fixing unit 60 for fixing the toner image transferred to the recording material 151 by the secondary transfer unit 50 to the recording material 151 and a recording material 151 passing through the secondary fixing unit 50 are fixed below A transport means 600 for transporting to the section 60 is arranged. The conveying unit 600 includes an endless conveying belt 603 wound around rollers 601 and 602, one of which is a driving side, and is arranged between the secondary transfer unit 50 and the fixing unit 60 to form a conveying path. There is. An electrostatic attraction force or an attraction force such as air is applied to the conveyor belt 603 by a well-known attraction means (not shown) so that the recording material 151 having passed through the secondary transfer portion 50 is attracted. A transport guide member 604 is disposed between the transport unit 600 and the fixing unit 60.

The fixing means 107 includes a roller 107a as a heating rotator having a heating member inside and a roller 107.
a roller 107b as an opposed rotating body that is arranged to face a
It has and. One of the rollers 107a and 107b is in pressure contact with the other roller. In this embodiment, the roller 107b is in pressure contact with the roller 107a, and the pressure contact portion of both rollers is the fixing portion 60. Roller 107a
The roller 601 on the drive side is driven to rotate by the drive motor 130. The conveyor belt 603 is a roller 60.
When 1 is rotationally driven, the surface 603a is rotationally moved counterclockwise at the linear velocity Vp. The roller 107a and the roller 107b are driven by the drive motor 130.
The outer peripheral surface is rotated at the linear velocity Vp.

The fixing means 107 of the present embodiment is a so-called roller fixing system, but is a belt fixing system in which a belt is wound around a plurality of rollers, a roller is provided so as to face the belt, and the belt is pressed against each other. Good. In this case, the fixing portion is a pressure contact portion between the belt and the roller. Reference numeral 108 indicates a pair of discharge rollers, and reference numeral 109 indicates the fixing unit 6.
A tray for receiving the recording material 151 on which the image has been fixed by passing 0 is shown.

Below the conveying means 600, a paper feeding section 150 is provided.
Are arranged. The paper feeding unit 150 includes a cassette tray 155 capable of stacking and storing the recording materials 151, a delivery roller 152 for delivering the stacked and storing recording materials 151, and a conveyance path for guiding the delivered recording materials 151 to the secondary fixing unit 50. 156, a conveyance roller pair 153 provided on the conveyance path 156, and a registration roller pair 154 arranged immediately before the secondary transfer unit 50.

In the image forming apparatus according to this embodiment, the distance between the secondary transfer portion 50 and the primary transfer portion 40BK, which is the primary transfer portion closest to the secondary transfer portion 50, is Lb. The distance between the section 50 and the fixing section 60 is Lf, and the recording material 151
Lf> Lp, where Lp is the maximum length of the
> Lb. The distance Lb is equal to the intermediate conveyance belt 301.
From the center of the primary transfer portion 40BK in the moving direction of the recording medium 151 to the center of the secondary transfer portion in the conveying direction of the recording material 151, and the distance Lf is from the center of the secondary transfer portion to the fixing portion 60 in the conveying direction of the recording material 151. Point to the center.

As shown in FIG. 3, the image forming apparatus has a switching means 140. A main part of a well-known microcomputer is configured in the switching means 140, and the drive motors 120 and 130, the recording material type setting means 150, and the sensor 160 are connected via wiring. Switching means 1
The type of recording material applicable to the apparatus and the number of rotations of the drive motors 120 and 130 corresponding to the type are stored in 40. The recording material type setting unit 150 is an operation unit that selectively sets the type of the recording material 151.

The operation of the image forming apparatus having such a configuration will be described with reference to the flowchart shown in FIG. Step R1
Then, when the type of the recording material 151 is set by the recording material type setting means 150 and the image signal is input by operating the start key (not shown), the drive motor 12 is operated in step R2.
Each unit including 0 and 130 is driven. At this time, the drive motors 120 and 130 are driven so that Vb = Vp. When the drive motors 120 and 130 are driven, each photoconductor rotates to form a toner image, and the intermediate transfer belt 301 rotates and moves in the clockwise direction.
03 rotates counterclockwise. Photosensitive members 102Y, 102M, 102C, 1 which rotate in the direction of the arrow in FIG.
02BK is a charging unit 103Y, 103M, 103C,
The outer peripheral surface of 103BK is uniformly charged. Optical writing means 110Y, 110M, 110C, 110BK
Light is modulated and emitted corresponding to each reproduced color, and the charged photoconductors 102Y, 102M, 102C, 102 are charged.
The outer peripheral surface of BK is exposed and scanned with a laser beam. By this exposure, the photoconductors 102Y, 102M, 102C, 102B
The electrostatic latent image corresponding to each reproduced color formed on K is the developing device 104Y, 104M, which contains the toner of each reproduced color,
The toner images of the respective colors are developed by 104C and 104BK, respectively.

Photoreceptors 102Y, 102M, 102C, 1
The Y, M, C, and BK toner images formed on the 02BK are sequentially transferred onto the surface 301a of the intermediate transfer belt 301 by the action of the primary transfer units 105Y, 105M, 105C, and 105BK (primary transfer). To be done. The primary-transferred toner image is carried to the secondary transfer unit 50 by the movement of the intermediate transfer belt 301, and secondarily transferred to the recording material 151 fed from the cassette tray 155 all together. Two
The next-transferred toner image on the recording material 151 is adsorbed by the conveyor belt 603 of the conveyor unit 600 and conveyed toward the fixing unit 60.

The drive motors 120 and 130 are operated in step R
In step 3, the recording material 151 is driven so that Vb = Vp until the trailing edge of the recording material 151 is detected by the sensor 150. And
When the sensor 150 detects the trailing edge of the recording material 151, the type of the recording material 151 is determined in step R4. The setting made by the recording material type setting means 150 is thick paper or OH.
If it is plain paper instead of P sheet, go to step R6.
The speed control for the drive motors 120 and 130 is not executed, and the speed of Vb = Vp is maintained.

Therefore, the recording material 151 conveyed to the fixing section 60 is conveyed to the fixing section without changing the conveying speed. Therefore, the toner image secondarily transferred to the recording material 151 is melted by heat and pressure on the recording material 151 at the fixing unit 60 and is well fixed as a full-color image.
The recording material 151 on which the toner image is fixed is discharged onto the tray 109 by the discharge roller pair 108.

On the other hand, if the setting made by the recording material type setting means 150 is thick paper or OHP sheet, in step R5, the drive motor 130 is decelerated so as to change the speed to Vp ≠ Vb. For this reason, the recording material 151 conveyed to the fixing unit 60 has a linear velocity V of the intermediate transfer belt 301.
The sheet is conveyed to the fixing unit 60 at a conveying speed Vp slower than b.
At this time, since the linear velocity of the roller 107a is also Vb,
The recording material 151 slowly passes through the fixing unit 60. Therefore, the toner image secondarily transferred to the recording material 151 is melted by sufficient heat and pressure on the recording material 151 and is well fixed as a full-color image. The recording material 151 on which the toner image is fixed is discharged onto the tray 109 by the discharge roller pair 108.

Generally, if Vp is set to a speed of about 1/2 to 1/3 of Vb, good fixing can be performed even on thick paper or OHP sheet. Therefore, if the speed of Vp is appropriately determined within this range, image formation is possible. Good image fixing performance can be obtained without changing the conditions.

Since the distance Lb between the primary transfer portion 40BK and the secondary transfer portion 50 is shorter than the maximum length Lp of the recording material 151, the apparatus can be downsized. In addition, the secondary transfer unit 5
Since the interval Lf between 0 and the fixing unit 60 is set longer than the maximum length Lp of the recording material 151 in the transport direction, the recording material 15
Regardless of the conveyance speed of 1, the conveyance belt 603 does not loosen or buckle during conveyance. Therefore, the conveyor belt 60
3 above the intermediate transfer belt 301 and the recording material 15
The contact with the toner image on No. 1 can be avoided, and a good image without image distortion can be obtained.

In the present embodiment, the recording material 151 is the secondary transfer portion 5
The speed of the drive motor 130 is controlled by determining the type of the recording material 151 when passing 0, but a plurality of speed control modes are preset in the switching means 140 for each type of the recording material 151. Recording material 1 by the recording material type setting means 150
When the 51 types are selected and set, the speed control mode corresponding thereto may be selected and executed to change the speed of the drive motor 130 by the switching means 140.

In this embodiment, the drive motor 130 is controlled to control the linear velocity Vp of the intermediate conveying belt 301 and the recording material 151.
However, the present invention is not limited to such a form. Cardboard and OHP
Sheets and the like have a problem that they have fixing conditions equivalent to those of thin paper and plain paper. Therefore, when the fixing conditions for thick paper or OHP sheet are used as a reference, the fixing temperature becomes high, and the phenomenon that thin paper or plain paper is wrapped around in the fixing unit 60, and these recording materials 151
A so-called hot offset phenomenon in which the upper toner is transferred to the roller 107a may occur. Therefore, when using thin paper or plain paper, the linear velocity Vp of the intermediate transport belt 301 may be increased to about 1.5 to 2 times the transport speed Vb of the recording material 151. In short, the drive means such as the corresponding drive motors 120 and 30 are controlled so that there is a relative speed difference between the linear speed Vb of the intermediate transfer belt 301 and the transport speed Vp of the recording material 151 depending on the type of the recording material 151. do it.

This embodiment is an example applied to a tandem type image forming apparatus, but it is needless to say that it is applied to a four cycle type image forming apparatus.

Generally, a four-cycle type image forming apparatus is
One image carrier on which a toner image is formed, a primary transfer unit that sequentially transfers the toner image formed on the image carrier to an intermediate transfer member, and the image transferred to the intermediate transfer member is transferred to a recording material. The secondary transfer unit that performs the secondary transfer, the fixing unit that fixes the transferred image on the recording material, and the revolver-type developing unit having the toners of Y, M, C, and BK are included. When the distance between the printing unit and the fixing unit is Lf, the maximum length of the recording material in the transport direction is Lp, and the distance between the primary transfer unit and the secondary transfer unit is Lb, Lf>Lp> Lb. . Further, as in the present embodiment, a conveyance unit that conveys the recording material to the fixing unit is provided between the secondary transfer unit and the fixing unit, and the image carrier and the intermediate transfer member are rotationally driven by the driving unit. Vd = Vb, Vp = Vb, where Vd is the linear velocity of the outer peripheral surface, Vb is the linear velocity of the surface of the intermediate transfer member, and Vp is the transport velocity of the recording material.
Alternatively, the speed can be changed to Vp ≠ Vb, and when the image transfer from the intermediate transfer member to the recording material is completed, Vp =
The speed may be switched from Vb to Vp ≠ Vb.

[0031]

According to the present invention, when the relationship between the distance Lf between the secondary transfer portion and the fixing portion and the maximum length Lp of the recording material in the conveying direction is Lf> Lp, the secondary relation to the recording material is obtained. When the transfer is completed, the leading edge of the recording material does not reach the fixing section, so slack and buckling will not occur even if the recording material conveyance speed changes, and good fixing properties will be obtained regardless of the type of recording material. While securing, a good image can be obtained without the need to change the image forming conditions.

According to the present invention, the distance Lb between the primary transfer portion and the secondary transfer portion, which are located closer to the secondary transfer portion of the plurality of primary transfer portions, is set to the distance between the secondary transfer portion and the fixing portion. If it is shorter than the distance Lf or the maximum length Lp of the recording material in the conveying direction, the first
Even when the primary transfer and the secondary transfer are simultaneously performed in the transfer section and the second transfer section, the leading edge of the recording material does not reach the fixing section when the secondary transfer to the recording material is completed, so that the recording material Slack and buckling will not occur even if the transport speed of the recording medium changes, and good images can be obtained without changing image forming conditions while maintaining good fixability regardless of the type of recording material. .

According to the present invention, since the distance Lb between the secondary transfer portion and the fixing portion is longer than the maximum length Lp of the recording material in the conveying direction even when the conveying speed Vp of the recording material is switched, the secondary Since slack and buckling of the recording material do not occur between the transfer section and the fixing section, good fixing performance can be ensured regardless of the type of recording material, and it is not necessary to change the image forming conditions. You can get an image.

According to the present invention, when the image transfer from the intermediate transfer member to the recording material is completed, Vp =
Since the relative velocity between the linear velocity of the surface of the intermediate transfer member and the transport velocity of the transport unit is switched so that Vb becomes Vp ≠ Vb, it is not necessary to change the image forming conditions and the recording medium is good regardless of the type of recording material. Excellent fixing property can be secured and a good image can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a tandem image forming apparatus having four image carriers to which the present invention is applied.

FIG. 2 is a diagram showing a positional relationship between an image carrier and an intermediate transfer member when the color image forming apparatus shown in FIG. 1 is viewed from a side surface.

FIG. 3 is a block diagram showing a configuration of a switching unit and a main part connected to the switching unit.

FIG. 4 is a flowchart showing one form of speed control of a drive motor performed by a switching unit.

[Explanation of symbols]

102 (Y, M, C, BK) image carrier 301 Intermediate transfer body 40 (Y, M, C, BK) Primary transfer part 50 Secondary transfer section 60 fixing unit 120 driving means 140 switching means 151 recording material 600 transportation means

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H027 DC02 ED16 ED25 EE03 EE04                       EF09                 2H030 AB02 AD04 AD05 AD17 BB42                       BB46 BB53 BB63                 2H072 AB09 AB19 AB20 CA05 JA03                 2H200 FA04 FA17 GA04 GA07 GA10                       GA12 GA23 GA31 GA34 GA47                       GA49 GB11 GB22 GB25 GB26                       GB30 HA02 HA28 HB07 HB12                       JA02 JA23 JB06 JB18 JB20                       JB25 JB28 JB49 JC03 JC07                       JC09 LA12 LA14 LA19 LA27                       PA11 PB25                 3F049 AA10 EA10 LA02 LA05 LA07                       LB03

Claims (4)

[Claims] 1. An image forming apparatus for obtaining a color image by superposing a plurality of toner images, wherein a plurality of image carriers on which toner images are formed and an image formed on the image carrier are intermediately transferred. A plurality of 1s arranged in parallel and sequentially transferred to
An image forming apparatus having a secondary transfer portion, a secondary transfer portion for transferring the image transferred to the intermediate transfer member onto a recording material, and a fixing portion for fixing the transferred image on the recording material An image forming apparatus, wherein Lf> Lp, where Lf is the distance between the fixing unit and the fixing unit and Lp is the maximum length of the recording material in the conveying direction. 2. The image forming apparatus according to claim 1, wherein the distance between the primary transfer portion and the secondary transfer portion, which are arranged near the secondary transfer portion of the plurality of primary transfer portions, is Lb. , L
An image forming apparatus characterized in that f>Lp> Lb. 3. The image forming apparatus according to claim 1, further comprising a driving unit that rotationally drives the image carrier and the intermediate transfer member, and a transport unit that transports the recording material to the fixing unit. When the linear velocity of the outer peripheral surface of each image carrier is Vd, the linear velocity of the surface of the intermediate transfer member is Vb, and the transport speed of the recording material is Vp, then Vd = Vb and Vp = Vb or Vp ≠ An image forming apparatus characterized in that the speed can be changed to Vb. 4. The image forming apparatus according to claim 3, further comprising switching means for switching the speed from Vp = Vb to Vp ≠ Vb when the image transfer from the intermediate transfer member to the recording material is completed. Image forming apparatus.