JP5769540B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer having a function of forming an image on a recording material such as a sheet.

2. Description of the Related Art Conventionally, a configuration having an intermediate transfer belt is known as an image forming apparatus such as a copying machine or a laser printer.
The image forming apparatus forms a color image (multiple image) on a recording material by performing a primary transfer process and a secondary transfer process on a toner image formed on an image carrier. In the image forming apparatus described in Patent Document 1, as a configuration of the intermediate transfer belt unit, a roller that stretches the intermediate transfer belt includes a driving roller, a driven roller, and a tension roller that are secondary transfer opposing members. .
The driving roller as the secondary transfer facing member sequentially conveys the intermediate transfer belt to the primary transfer process of each color, transfers the toner image to the recording material at the nip portion with the transfer roller, and conveys the recording material. It has a function to do. The driven roller is composed of a small-diameter roller and has a function of regulating the position of the intermediate transfer belt so that the recording material enters the secondary transfer contact portion (secondary transfer nip) along the intermediate transfer belt. .
This forms a space-saving intermediate transfer belt unit and suppresses image defects (so-called scattering) in which the transfer electric field upstream of the secondary transfer nip acts on the toner image on the transfer belt and blurs the toner image. Yes.

JP 2009-69466 A

However, in the configuration as described above, since the toner image transport path is actually long, the printing operation is started and the toner image is transferred to the recording material and discharged from the image forming apparatus. There was concern that a long time would be required.
Specifically, in the above-described intermediate transfer belt system, the toner image on the intermediate transfer belt is conveyed as follows by a driving roller that is a secondary transfer opposing member. First, the image is transferred onto the intermediate transfer belt at the primary transfer portion of the first color, and then sequentially passes around the tension roller through the primary transfer process of the second, third, and fourth colors, and is conveyed to the lower surface side of the intermediate transfer unit. Then, after the driven roller is rotated, it is conveyed to the secondary transfer nip.
In other words, the toner image on the intermediate transfer belt is configured to reach the secondary transfer portion for the first time after having passed the intermediate transfer belt about one turn from the primary transfer step of the first color. It took a lot of time to carry it.
For this reason, when a series of image forming operations are performed, the time (FPOT () from when the image formation start signal is input to the control unit until the first sheet material on which the image is formed is discharged out of the apparatus. It is desirable to shorten First Print Out Time)).
The present invention has been made in view of the above-described circumstances, and in an image forming apparatus having an intermediate transfer belt, the scattering at the time of secondary transfer is suppressed, the first printout time is shortened, and the apparatus It aims at realizing miniaturization of the.

In order to achieve the above object, the present invention provides:
An image carrier on which a toner image is formed;
An endless intermediate transfer belt on which a toner image formed on the image carrier is primarily transferred at a primary transfer nip formed between the image carrier and the image carrier;
An intermediate transfer roller on which a toner image primarily transferred to the intermediate transfer belt is secondarily transferred at a secondary transfer nip formed between the intermediate transfer belt;
One of a plurality of stretching rollers that stretch the intermediate transfer belt, and is provided to face the intermediate transfer roller so as to sandwich the intermediate transfer belt with the intermediate transfer roller. A counter roller for forming the secondary transfer nip,
A transfer member that forms a tertiary transfer nip with the intermediate transfer roller, and a transfer member for tertiary transfer of the toner image transferred onto the intermediate transfer roller to a recording material at the tertiary transfer nip;
In an image forming apparatus having
The toner image primarily transferred to the intermediate transfer belt passes from the intermediate transfer belt to the intermediate transfer roller at the secondary transfer nip without passing through the outer circumference of the plurality of stretching rollers other than the counter roller. Secondary transferred,
The intermediate transfer roller is disposed such that the secondary transfer nip and the primary transfer nip are located on the same plane,
When the cross section orthogonal to the rotation axis of the counter roller is taken, the rotation axis of the intermediate transfer roller is closer to the primary transfer nip side than the rotation axis of the counter roller in a direction parallel to the same plane. It is arranged.

  According to the present invention, in an image forming apparatus having an intermediate transfer belt, scattering at the time of secondary transfer can be suppressed, the first printout time can be shortened, and the apparatus can be downsized. .

Sectional drawing which shows schematic structure of the image forming apparatus of Example 1. FIG. Sectional drawing which shows schematic structure of the secondary transfer part vicinity of the image forming apparatus of Example 1. FIG. Sectional drawing which expanded the secondary transfer part of Example 1, and the tertiary transfer part vicinity Sectional drawing which expanded the secondary transfer part of Example 2, and the tertiary transfer part vicinity The perspective view which showed an example of the drive structure which gives rotational force to the rotating cam of Example 2. FIG.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

Example 1 will be described below.
FIG. 1 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus according to the present exemplary embodiment.
First, the configuration and operation of the image forming apparatus of this embodiment will be described with reference to FIG. The image forming apparatus according to the present exemplary embodiment includes first (Y) to fourth (Bk) image forming stations, the first being yellow (Y), the second being magenta (M), and the third being cyan (C ) And fourth is black (Bk). Hereinafter, the image forming operation will be described using the first station (Y). In the following description, “upper” and “lower” refer to the vertical direction in the installed state of the image forming apparatus.

(Image forming device)
The image forming apparatus includes a drum-shaped electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 as an image carrier, and the photosensitive drum 1 is rotationally driven in a direction indicated by an arrow in the drawing at a predetermined peripheral speed (process speed). .
In this rotation process, the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the charging roller 2 and then subjected to image exposure by the image exposure means 5. Thereby, an electrostatic latent image corresponding to the yellow component image of the target color image is formed. Next, the electrostatic latent image is developed at the developing position by the developing roller 3 of the first developing device (yellow developing device) and visualized as a yellow toner image.

The intermediate transfer belt 10 is stretched by a drive roller 11 and a tension roller 12 and is rotationally driven at substantially the same peripheral speed as that of the photosensitive drum 1 in a direction in which the intermediate transfer belt 10 moves in the same direction at a facing portion in contact with the photosensitive drum 1. The Here, the driving roller 11 and the tension roller 12 correspond to a plurality of stretching rollers. Further, the driving roller 11 corresponds to a counter roller that forms the secondary transfer nip N2 by being provided facing the secondary transfer roller 13 so as to sandwich the intermediate transfer belt 10 with the secondary transfer roller 13. To do.
The yellow toner image formed on the photosensitive drum 1 (on the image carrier) is applied to the primary transfer roller 14 in the process of passing through the primary transfer nip N1 between the photosensitive drum 1 and the intermediate transfer belt 10. The image is transferred onto the intermediate transfer belt 10 by the primary transfer voltage (primary transfer). The primary transfer residual toner remaining on the surface of the photosensitive drum 1 is cleaned and removed by the cleaning unit 4 and then subjected to an image forming process after charging. Here, the intermediate transfer belt 10 is an endless belt member that carries and conveys the primarily transferred toner image.

Similarly, a magenta toner image of the second color, a cyan toner image of the third color, and a black toner image of the fourth color are formed and transferred in succession on the intermediate transfer belt 10 to obtain a target color image. A composite color image corresponding to is obtained.
The four color toner images on the intermediate transfer belt 10 are applied to the secondary transfer roller 13 in accordance with the timing of reaching the secondary transfer nip N2 between the intermediate transfer belt 10 and the secondary transfer roller 13. Batch transfer (secondary transfer) is performed to the secondary transfer roller 13 by the transfer voltage.

Thereafter, the toner image on the secondary transfer roller 13 is fed to the feeding cassette 21 of the feeding means 20 in accordance with the timing at which the toner image reaches the tertiary transfer nip N3 between the secondary transfer roller 13 and the tertiary transfer roller 15. The uppermost recording material P loaded is sent out by the feeding roller 22.
The recording material P sent out by the feeding roller 22 is conveyed to the tertiary transfer nip N3 by the conveying roller 17. While the recording material P passes through the tertiary transfer nip N3, the toner image on the secondary transfer roller 13 is collectively transferred onto the surface of the recording material P by the tertiary transfer voltage applied to the tertiary transfer roller 15. (Tertiary transfer). Here, the secondary transfer roller 13 corresponds to an intermediate transfer roller. The tertiary transfer roller 15 corresponds to a transfer member.
Thereafter, the recording material P carrying the four color toner images is introduced into the fixing nip of the fixing roller pair 40 of the fixing device, where the four color toners are melted and mixed into the recording material P by being heated and pressurized. Fixed (fixed). Here, the fixing roller pair 40 corresponds to a pair of rotating members that convey the toner image on which the toner image is tertiary transferred while sandwiching the recording material and heat the toner image on the recording material.

With the above operation, a full color print image is formed on the recording material P.
Further, the secondary transfer residual toner remaining on the surface of the intermediate transfer belt 10 is cleaned and removed by the intermediate transfer belt cleaning device 16. The image forming apparatus used in this embodiment is an example and does not particularly limit the invention.

(Features of this embodiment)
Hereinafter, the configuration in the vicinity of the secondary transfer portion, which is a feature of this embodiment, will be described with reference to FIG.
2A and 2B are cross-sectional views illustrating a schematic configuration in the vicinity of the secondary transfer portion of the image forming apparatus according to the present exemplary embodiment.

The secondary transfer roller 13 is in contact with the driving roller 11 that is a transfer counter roller via the intermediate transfer belt 10 and is in contact with the tertiary transfer roller 15 and rotates clockwise as indicated by the arrow in the figure. Supported as possible.
The center (rotation axis) 13a of the secondary transfer roller 13 is above the position of the center (rotation axis) 11a of the drive roller 11 and inside the apparatus main body (inside the apparatus main body, on the primary transfer nip side, photosensitive). Arranged on the drum 1 side).
That is, in FIG. 2A, a horizontal line 13y passing through the center 13a of the secondary transfer roller 13 and a vertical (vertical) line 13x passing through the center 13a of the secondary transfer roller 13 are as follows. That is, the horizontal line 13y is located above the horizontal line 11y passing through the center 11a of the drive roller 11, and the vertical line 13x is located on the right side (inside the apparatus main body) of the vertical line 11x passing through the center 11a of the drive roller 11. doing.

  Here, in this embodiment, a belt plane stretched by two rollers of the intermediate transfer belt 10 (a belt plane between the driving roller 11 and the primary transfer nip N1, a belt stretch plane, the same plane). The image forming apparatus is installed so that 10a is horizontal. When the image forming apparatus is installed with the belt plane 10a not horizontal, the secondary transfer roller 13 is disposed on the same side as the photosensitive drum 1 with respect to the belt plane 10a in a direction orthogonal to the belt plane 10a. The Rukoto. That is, the secondary transfer roller 13 is disposed such that the primary transfer nip N1 and the secondary transfer nip N2 are positioned on the belt plane 10a (on the same plane). Further, when the cross section orthogonal to the center 11a of the drive roller 11 is taken, the center 13a of the secondary transfer roller 13 is closer to the primary transfer nip N1 side than the rotational axis of the drive roller 11 in the direction parallel to the belt plane 10a. Is arranged.

  Therefore, the toner image on the intermediate transfer belt 10 for which the primary transfer of the fourth color has been completed is conveyed to the secondary transfer nip N2, transferred to the secondary transfer roller 13 at once, and then immediately conveyed to the tertiary transfer nip N3. Then, it is collectively transferred to the recording material P. At this time, the toner image primarily transferred to the intermediate transfer belt 10 is carried on the secondary transfer nip N2 without passing through the outer periphery (peripheral surface portion) of a roller (tension roller 12) other than the driving roller 11 (other than the opposing roller). Be transported.

2A, the center 15a of the tertiary transfer roller 15 is on a horizontal line 13y passing through the center 13a of the secondary transfer roller 13, and is formed by the secondary transfer roller 13 and the tertiary transfer roller 15. The third transfer nip tangent line (shown by a broken line in FIG. 2A) is in the vertical direction. This configuration is realized by the nip of the fixing roller pair 40 being located on a vertical plane including the tertiary transfer nip N3. In this embodiment, with the image forming apparatus installed, the intermediate transfer belt 10 is disposed below the photosensitive drum 1, and the fixing roller pair 40 is disposed above the tertiary transfer nip N3. Has been.
Accordingly, since the recording material P introduced from the conveying roller 17 is discharged from the tertiary transfer nip N3 in the vertical direction, it is necessary to secure an extra space as a conveying path for the recording material P in the image forming apparatus. Therefore, it is possible to reduce the size of the image forming apparatus.

In FIG. 2B, the center 15a of the tertiary transfer roller 15 is disposed above the horizontal line 13y, and a tertiary transfer nip tangent line formed by the secondary transfer roller 13 and the tertiary transfer roller 15 (FIG. 2). (B) is indicated by a broken line) inclined toward the inside of the apparatus main body from the vertical direction. This configuration is realized by the nip of the fixing roller pair 40 being located inside the apparatus main body with respect to the vertical plane including the tertiary transfer nip N3.
That is, the recording material P introduced from the conveying roller 17 is discharged from the tertiary transfer nip N3 toward the inside of the apparatus main body. Even in this configuration, an extra conveyance path for the recording material P is provided in the image forming apparatus. There is no need to secure a space, and the apparatus can be miniaturized.

(Operation of this embodiment)
Next, the operation of this embodiment will be described.
2A, the center 13a of the secondary transfer roller 13 is disposed above the center 11a of the driving roller 11 and inside the apparatus main body, so that the surface of the secondary transfer roller 13 is moved to the secondary transfer nip. It can be brought into contact with the intermediate transfer belt 10 before N2. That is, the toner image primarily transferred onto the intermediate transfer belt 10 is in contact with the secondary transfer roller 13 along the belt plane 10a that is in contact with the photosensitive drum 1, and the toner image transport direction (belt rotation direction). It is possible to enter the secondary transfer nip N2 after a sufficient distance from the upstream.
As a result, the transfer electric field upstream of the secondary transfer nip N2 in the toner image conveying direction acts on the toner image on the intermediate transfer belt 10 and pre-transfers onto the secondary transfer roller 13 (on the intermediate transfer roller). The scattering phenomenon can be suppressed.

  At the same time, as shown in FIG. 2A, the toner image on the intermediate transfer belt 10 is batch-transferred onto the recording material P as follows. That is, after the primary transfer of the fourth color is completed, the transfer is immediately performed on the surface of the secondary transfer roller 13 without going around the outer periphery of the drive roller 11, and thereafter, the surface of the secondary transfer roller 13 is also slightly 1 / The image is immediately transferred onto the recording material P just by going around four rounds. With such a configuration, it is possible to greatly reduce the distance at which the toner image is conveyed.

FIG. 3 is an enlarged cross-sectional view of the vicinity of the secondary transfer unit and the tertiary transfer unit for easy understanding of the influence on the toner image transport distance and the apparatus main body size.
FIG. 3A is a diagram illustrating an example (comparative example) in which the center 13a of the secondary transfer roller 13 is located above the center 11a of the drive roller 11 but is disposed outside the apparatus main body. In this example, the angle A formed by the tertiary transfer nip tangent (shown by a broken line in FIG. 3A) and the stretched surface of the intermediate transfer belt 10 in contact with the photosensitive drum 1 is greater than 90 °. .
In FIG. 3A, the toner image on the intermediate transfer belt 10 is transferred onto the secondary transfer roller 13 in a lump after the primary transfer of the fourth color is completed and then a part of the circumferential surface of the drive roller 11 is circulated. Will be. After that, after having circulated a distance of about a half circumference on the circumferential surface of the secondary transfer roller 13, it is conveyed to the tertiary transfer nip N3 and is collectively transferred to the recording material P.

FIG. 3B is a diagram for explaining the above-described embodiment. A tertiary transfer nip tangent (indicated by a broken line in FIG. 3B) and a belt of the intermediate transfer belt 10 that contacts the photosensitive drum 1. The angle B formed with the plane 10a is 90 °.
In the configuration of this embodiment shown in FIG. 3B, the distance over which the toner image is conveyed is significantly shortened as can be seen from the comparison with FIG. That is, in this embodiment, the time (FPOT (First Print Out Time)) from when the user starts the printing operation to when the toner image is transferred to the recording material P and discharged to the outside of the image forming apparatus is shortened. Things are possible.
Here, the distances x and y in FIG. 3 are numerical values representing the difference in the position of the tertiary transfer roller 15 in the apparatus main body in each configuration of FIGS.

FIG. 3C is a diagram for explaining the above-described embodiment. The tertiary transfer nip tangent (shown by a broken line in FIG. 3C) and the tension of the intermediate transfer belt 10 in contact with the photosensitive drum 1 are illustrated. The angle C formed with the frame is 90 ° or less.
In the configuration of this embodiment shown in FIG. 3C, the position of the tertiary transfer roller 15 in the apparatus main body is the distance x and the distance y, as can be seen from comparison with FIGS. 3A and 3B. Is arranged inside the main body of the device. As a result, space saving can be achieved, and downsizing of the image forming apparatus main body can be realized.

As described above, in this embodiment, the tertiary transfer roller 15 responsible for the tertiary transfer process is provided, and when the primary transfer process for each color is completed, the toner image on the intermediate transfer belt 10 is immediately transferred to the secondary transfer process. In addition, the third transfer process is continuously performed. Further, the center 13a of the secondary transfer roller 13 is disposed above the center 11a of the driving roller 11 and inside the apparatus main body.
As a result, the distance to which the toner image is conveyed is greatly shortened, and the time from when the user starts the printing operation to when the toner image is transferred to the recording material P and discharged outside the image forming apparatus (FPOT) Can be shortened. At the same time, since the tertiary transfer roller 15 can be disposed inside the apparatus main body, space can be saved, and the image forming apparatus main body can be downsized. Further, the secondary transfer roller 13 can be brought into contact with the intermediate transfer belt 10 upstream of the secondary transfer nip N2, so that the secondary transfer electric field acts on the toner image on the intermediate transfer belt 10 and pre-transfers. It is possible to suppress a serious scattering phenomenon (image defect in which a toner image is blurred). Further, by setting the angle formed by the straight line formed by the tertiary transfer nip N3 and the fixing nip and the belt plane 10a to 90 ° or less, the discharge direction of the recording material after the third transfer is limited, and the depth of the apparatus main body is limited. The image forming apparatus can be reduced in size without providing an extra space in the direction.

Hereinafter, Example 2 will be described with reference to FIGS. 4 and 5. In addition, the same code | symbol is attached | subjected about the component similar to Example 1, and the description is abbreviate | omitted.
In this embodiment, the secondary transfer roller 13 is supported so as to be able to contact and separate (can be contacted and separated) with respect to the driving roller 11 and the tertiary transfer roller 15. A mechanism for preventing generation of a set mark of the transfer roller 13 is added.

  The secondary transfer roller 13 pressed against the driving roller 11 via the intermediate transfer belt 10 preferably has a large capacitance in order to suppress toner scattering. In this embodiment, the elastic layer has a low resistance. And it is set as the two-layer structure of the surface layer of a high resistance thin layer. The elastic layer is made of acrylonitrile butadiene rubber (NBR), silicone rubber, etc., and the surface layer is a dispersion of PTFE powder with urethane resin as a binder for the purpose of improving releasability, or fluorine rubber or acrylic with excellent releasability. A high resistance layer made of resin or the like is used.

  When the secondary transfer roller 13 made of these materials is left pressed against the drive roller 11 and the tertiary transfer roller 15 for a long period of time, each nip is deformed while being depressed, and so-called set marks are generated. There is a concern that When the printing operation is performed in a state where such a set mark is generated, the toner image is disturbed at the set mark portion, and the toner image appears to be white on the recording material P to which the toner image is transferred. The image becomes defective.

  FIG. 4 is an enlarged cross-sectional view of the vicinity of the secondary transfer unit and the tertiary transfer unit, which are characteristic parts in the present embodiment. FIG. 4A is a diagram illustrating a state in which the secondary transfer roller 13 is in contact with the drive roller 11 and the tertiary transfer roller 15. FIG. 4B is a diagram illustrating a state in which the secondary transfer roller 13 is separated from the driving roller 11 and the tertiary transfer roller 15.

  As shown in FIG. 4A, a rotating cam 31 is provided on the rotating shaft of the driving roller 11, and a rotating roller 32 that can move on the peripheral surface is disposed at the tip of the slide guide 35. The rotation shaft 33 of the secondary transfer roller 13 is pressed in the direction of the rotation axis of the drive roller 11 by a pressing spring 34 and supported so as to be movable along a slide guide 35. Here, the rotating cam 31, the rotating roller 32, the pressing spring 34, and the slide guide 35 constitute contact / separation means.

From the state shown in FIG. 4A, the rotation cam 31 on the rotation shaft of the drive roller 11 rotates in the direction of the arrow in the figure, so that the secondary transfer roller 13 is driven by the drive roller 11 and the tertiary transfer roller 15 respectively. It is comprised so that it may space apart from. This is because the rotating roller 32 rotates on the circumferential surface of the rotating cam 31 while the rotating cam 31 rotates from the state shown in FIG. 4A until it stops at the position shown in FIG. By moving along 35.

  Further, the tertiary transfer roller 15 is fixed to the driving roller 11 with high accuracy by a frame (not shown). As a result, when the secondary transfer roller 13 is pressed against the driving roller 11, the secondary transfer roller 13 contacts the tertiary transfer roller 15 with a predetermined pressing force against the tertiary transfer roller 15 at the same time. It has become.

FIG. 5 is a schematic perspective view showing an example of a drive configuration that applies a rotational force to the rotary cam 31.
A rotational drive force is input to the drive gear 46 by a drive source (not shown), the rotational drive force is transmitted to the gears 45, 44, 43, and the rotation provided along with the rotational cam 31 on the rotational shaft of the drive roller 11. The cam gear 42 is driven to rotate.

  The rotating cam 31 and the rotating cam gear 42 are supported so as to be rotatable independently of the rotation of the driving roller 11, and are configured to act only when the secondary transfer roller 13 is in contact with and separated from the rotating roller 31. A gear similar to the gear 43 is provided on the other end side of the rotating shaft 47 of the gear 43, and a gear and a rotating cam (not shown) provided on the rotating shaft of the driving roller 11 as in the illustrated driving side. Is configured to rotate.

The contact / separation operation may be performed at a timing that is not during the image forming operation, and is performed, for example, at the time of post-rotation after the print job or when the power is turned off.
In this embodiment, the secondary transfer roller 13 is pressed against the driving roller 11 and the tertiary transfer roller 15 by the pressing spring 34. However, the present invention is not limited to this. For example, the position of the secondary transfer roller 13 in the image forming apparatus main body may be determined and fixed in accordance with the operation of the rotating cam 31.

As described above, in this embodiment, the tertiary transfer roller 15 responsible for the tertiary transfer step is provided, and the secondary transfer roller 13 is linked to the rotational operation of the rotary cam 31 and the drive roller 11 and the tertiary transfer. It is configured to be able to contact and separate from the roller 15.
As a result, it is possible to prevent the setting marks of the secondary transfer roller 13 from being generated, and even in the image forming apparatus after long-term storage, it is possible to prevent the occurrence of image defects such that the toner image is whitened. Become. Therefore, it is possible to improve the image quality when the image forming apparatus is operated after long-term storage.

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 10 ... Intermediate transfer belt, 10a ... Belt plane, 11 ... Drive roller, 11a ... Center of drive roller 11, 13 ... Secondary transfer roller, 13a ... Center of secondary transfer roller 13, 15 ... Tertiary Transfer roller, N1 ... primary transfer nip, N2 ... secondary transfer nip, N3 ... tertiary transfer nip

Claims (3)

An image carrier on which a toner image is formed;
An endless intermediate transfer belt on which a toner image formed on the image carrier is primarily transferred at a primary transfer nip formed between the image carrier and the image carrier;
An intermediate transfer roller on which a toner image primarily transferred to the intermediate transfer belt is secondarily transferred at a secondary transfer nip formed between the intermediate transfer belt;
One of a plurality of stretching rollers that stretch the intermediate transfer belt, and is provided to face the intermediate transfer roller so as to sandwich the intermediate transfer belt with the intermediate transfer roller. A counter roller for forming the secondary transfer nip,
A transfer member that forms a tertiary transfer nip with the intermediate transfer roller, and a transfer member for tertiary transfer of the toner image transferred onto the intermediate transfer roller to a recording material at the tertiary transfer nip;
In an image forming apparatus having
The toner image primarily transferred to the intermediate transfer belt passes from the intermediate transfer belt to the intermediate transfer roller at the secondary transfer nip without passing through the outer circumference of the plurality of stretching rollers other than the counter roller. Secondary transferred,
The intermediate transfer roller is disposed such that the secondary transfer nip and the primary transfer nip are located on the same plane,
When the cross section orthogonal to the rotation axis of the counter roller is taken, the rotation axis of the intermediate transfer roller is closer to the primary transfer nip side than the rotation axis of the counter roller in a direction parallel to the same plane. An image forming apparatus that is arranged. A pair of rotating bodies that convey the toner image on which the toner image has been thirdarily transferred and sandwich the recording material, and heat the toner image on the recording material;
With the image forming device installed,
The intermediate transfer belt is disposed below the image carrier, and
The pair of rotating bodies are disposed above the tertiary transfer nip, and
2. The image according to claim 1, wherein a nip of the pair of rotating bodies is positioned on a vertical plane including the tertiary transfer nip or positioned on the primary transfer nip side of the vertical plane. Forming equipment.   The image forming apparatus according to claim 1, further comprising a contact / separation unit that allows the intermediate transfer roller to contact and separate from the intermediate transfer belt and the transfer member.

Images