JP4928167B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image by transferring an image formed on a rotating image carrier to a belt member that is in contact with the image carrier and traveling to a recording medium carried on the belt member. .

  In the electrophotographic image forming apparatus, an electrostatic latent image is formed on a photosensitive drum as an image carrier, and a toner image is formed by an image forming unit. The toner image is transferred to a sheet on a transfer member of an endless belt, or transferred to a sheet after being transferred to a transfer member of an endless belt.

  Conventionally, in an image forming apparatus using this kind of endless belt body, the belt body is stretched by a plurality of rollers including a driving roller. Here, due to the parallelism error of these rollers, the cylindricity of each roller, the circumferential length difference between the front and back of the belt body, it moves in a direction perpendicular to the running direction of the belt body and is offset. There are problems such as stuttering and meandering. Phenomena such as deviation of the belt body and meandering cause image distortion and color misregistration in the case of multiple colors. In a worse case, the belt body may come off from the stretched roller.

  In view of this, a belt deviation control method has been proposed in which the inclination of the roller that stretches the belt body (angle relative to the running direction of the belt body) is controlled to suppress the deviation of the belt body and meandering within an allowable range ( Patent Document 1).

JP-A-6-9096

  However, in this type of belt deviation control method, even if the inclination of the stretched roller is changed to control the deviation of the belt body, the binding force of the photosensitive drum that is in pressure contact with the belt body is controlled. Therefore, it may be difficult to move the belt body in a direction perpendicular to the running direction of the belt body. Therefore, there is a possibility that the deviation control of the belt body becomes unstable.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an image forming apparatus capable of reliably controlling the deviation of the belt body.

A typical means in the present invention for solving the above-mentioned problems is that the image formed on the rotating image carrier is directly or directly on the belt member that is in contact with the image carrier and is conveyed by the belt member. In the image forming apparatus for transferring and forming an image, a deviation detecting means for detecting a deviation of the belt body when the belt body is running, a transfer roller that is driven to rotate while being pressed against the belt body so as to face the image carrier, Inclination changing means for changing the inclination of the transfer roller with respect to the running direction of the belt body in accordance with a detection result by the deviation detecting means.

In the present invention, the shift of the belt body can be corrected by changing the inclination of the transfer roller in accordance with the shift amount of the belt body. Further, the shift control can be stabilized without the press contact between the transfer roller and the belt body preventing the shift control.

Next, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings. Here, before describing the embodiment, a reference example will be described. The reference example shows an example in which a photosensitive drum serving as an image carrier is tilted to correct the deviation of the belt member .

[ Reference example ]
1 to 4 show an image forming apparatus according to a reference example . Here, first, the overall configuration of the image forming apparatus will be briefly described, and then the belt body shift control configuration, which is a feature of this reference example , will be described.

{Overall configuration of image forming apparatus}
FIG. 4 is a cross-sectional explanatory view of the image forming apparatus of this reference example . The image forming apparatus of this reference example illustrates an intermediate transfer type color printer in which four image stations are horizontally arranged.

In the image forming apparatus of the present reference example, an image forming unit 2 is disposed in the upper part of the printer main body 1 and a sheet conveying unit 4 is disposed in the lower part. In the image forming unit 2, four image forming stations for forming toner images of each color of yellow Y, magenta M, cyan C, and black Bk are arranged in the horizontal direction. Each image forming station is provided with a photosensitive drum 20 as an image carrier so as to be driven to rotate. Around the photosensitive drum 20, a charger 21 for charging the surface of the photosensitive drum 20 and an LED unit 22 as an exposure unit for forming an electrostatic latent image on the photosensitive drum 20 are disposed. Further, a developing unit 23 for developing toner on the electrostatic latent image on the photosensitive drum and a cleaner 26 for removing residual toner on the photosensitive drum are arranged.

  An intermediate transfer belt 24 as a belt body to which each photosensitive drum 20 can be pressed is rotatably provided below the photosensitive drum 20. Then, as the intermediate transfer belt 24 is driven, the photosensitive drum 20 is driven. Further, a primary transfer roller 25 is provided at a position facing each of the photosensitive drums 20 via the intermediate transfer belt 24 so as to be in contact with the intermediate transfer belt 24 so as to be driven to rotate.

  The intermediate transfer belt 24 is stretched by a driving roller 27, a secondary transfer inner roller 28, and a tension roller 29.

  At the time of image formation, each color toner image is formed by electrophotography on each photosensitive drum 20 that rotates counterclockwise in FIG. The toner images are sequentially superimposed and transferred onto the intermediate transfer belt 24 rotating in the clockwise direction in FIG. 4 by applying a bias to the primary transfer roller 25, thereby forming a color image.

  In synchronization with the image formation, the recording sheet P, which is a recording medium, is conveyed from the sheet conveying unit to the secondary transfer unit. The sheet conveyance unit 4 is configured so that the recording sheets P stored in the sheet cassette 40 are separated one by one by the feeding roller 41 and the separation roller pair 42 and conveyed to the registration roller pair 44 by the plurality of conveyance rollers 43. It is configured. The recording sheet P transported to the registration roller pair 44 is transported in synchronization with the position and timing of the toner image on the intermediate transfer belt 24.

  The toner image on the intermediate transfer belt 24 is transferred onto the recording sheet P by applying a bias to the secondary transfer outer roller 45. The recording sheet P is conveyed to the fixing device 47 by the conveyance belt 46 and the toner image is fixed, and then is discharged to the discharge tray 49 by the discharge roller 48.

{Belt offset control configuration}
The image forming apparatus of the present reference example is configured to detect and correct the shift of the intermediate transfer belt 24. Next, a configuration for that purpose will be described.

FIG. 1 is a schematic perspective view of the intermediate transfer belt 24 and the photosensitive drum 20 of the image forming apparatus according to the present reference example , and FIG. 2 is a view of a part thereof viewed from above the transfer surface.

As shown in FIG. 1, the intermediate transfer belt 24 stretched by the driving roller 27, the secondary transfer inner roller 28, and the tension roller 29 is moved in the direction of the arrow A by the rotation of the driving roller 27 in the direction of the arrow. Run. As described above, the intermediate transfer belt 24 may be deviated in a direction (belt width direction) perpendicular to the running direction due to a parallelism error of the stretched roller. In the image forming apparatus of this reference example , the shift of the intermediate transfer belt 24 is detected by a shift detection means.

  The deviation detecting means detects the deviation of the intermediate transfer belt 24 by detecting the end position by the belt end detection sensor 201 disposed at the end of the intermediate transfer belt 24 (end in the belt width direction). On the other hand, one end of the tension roller 29 in the longitudinal direction is configured to be movable within a small range. Then, by driving the swing motor 202 connected to the end portion, the tension roller 29 swings and the angle can be changed with respect to the belt width direction. Accordingly, the belt shift can be corrected by swinging the tension roller 29 according to the detection result of the belt end detection sensor 201. For example, when the tension roller 29 is moved from the position a in FIG. 1 to the position b, the intermediate transfer belt 24 moves (closes) in the direction of arrow B as it travels. By performing this operation as needed according to the detection signal of the belt end detection sensor 201, the intermediate transfer belt 24 is stably driven.

  Here, the intermediate transfer belt 24 is in pressure contact with the photosensitive drum 20 by the bias of the primary transfer roller 25. For this reason, as shown in FIG. 2, the intermediate transfer belt 24 receives a force F in a direction perpendicular to the rotation axis that is a tangential direction of the photosensitive drum 20 at the nip portion with the photosensitive drum 20. The direction of the force F is substantially perpendicular to the direction of the belt (in the direction of arrow B). However, if the photosensitive drum 20 is inclined due to the assembly accuracy of the photosensitive drum 20, the direction of the belt is shifted by the force F. A component force F1 parallel to B is generated. If the photosensitive drum 20 is tilted so that the direction of the component force F1 is opposite to the direction B in which the belt is desired to be moved, the belt shift correction cannot be stably performed.

Therefore, in this reference example , the component force F1 is positively used. When the intermediate transfer belt 24 is to be moved in the direction of the arrow B, the photosensitive force is generated so that the component force F1 is generated in the same direction as the arrow B. The body drum 20 is tilted.

  For example, as shown by the two-dot chain line in FIG. 2, when the photosensitive drum 20 is tilted, the component force F1 of the force F acts in the direction in which the intermediate transfer belt 24 is desired to move (direction of arrow B). When it is desired to control the intermediate transfer belt 24 to move in the direction opposite to the arrow B, the photosensitive drum 20 is inclined in the reverse direction.

  Therefore, an inclination changing unit is provided so that the angle of the rotation shaft of the photosensitive drum 20 can be adjusted. The inclination changing means of the photosensitive drum 20 changes the inclination of the photosensitive drum 20 with respect to the traveling direction of the intermediate transfer belt 24 according to the detection result by the deviation detecting means.

  Specifically, as shown in FIG. 3, the position of the bearing portion at one end of the photosensitive drum shaft 203 is movably supported. The photosensitive drum shaft 203 is rotatably supported by a bearing 204, and the bearing 204 is fixed to a holder 205. The holder 205 is movable in the traveling direction of the intermediate transfer belt 24, but is housed in a regulated rail shape in a direction orthogonal thereto.

  This holder 205 is sandwiched between a compression spring 206 and a pressure head 207. The pressure head 207 can be moved minutely by a double screw mechanism 208. The double screw is composed of an M10 × 1 right screw and an M5 × 0.8 left screw, and when the outer ring 209 is rotated once, the pressure head 207 moves by 1 mm−0.8 mm = 0.2 mm. A gear is provided on the outer periphery of the outer ring 209, and the amount of rotation is controlled by the amount of rotation of the stepping motor 210, and the amount of movement of the pressure head 207 is controlled.

The distance between the bearings supporting the photosensitive drum shaft 203 in this reference example is 380 mm, and when the pressure head 207 is moved by 0.66 mm, the photosensitive drum shaft is inclined by 0.1 °. If the reduction ratio of the outer ring 209 and the stepping motor 210 is set to 1/5, the rotation amount of the stepping motor 210 is 16.5 rotations. The control may be performed by rotating a predetermined fixed amount of the stepping motor 210 by the detection signal of the belt end detection sensor 201, or by rotating a proportional amount according to the signal value, that is, according to the signal value. Thus, the inclination amount of the photosensitive drum 20 may be changed.

  If the photosensitive drum 20 is tilted by moving the shaft support portion of the photosensitive drum shaft 203, it affects the drive train (not shown) for rotationally driving the photosensitive drum 20, but the inclination of the photosensitive drum is 0.5 °. The impact can be ignored if: Therefore, it is desirable that the amount of movement of the pressure head 207 is ± 1 mm or less where the inclination of the photosensitive drum is sufficiently small (sufficiently smaller than 0.5 °).

Note that the photosensitive drum 20 receives a force in the transport direction as the intermediate transfer belt 24 travels, so the compression spring 206 needs to set a sufficient load. In this reference example , a compression spring 206 having a load of 60 [N] is used at the center position (position where there is no inclination of the photosensitive drum shaft). According to the double screw mechanism used in the present reference example , the position can be maintained because the device main body is self-locked even when the power of the apparatus main body is turned off and the excitation of the stepping motor is stopped. Further, not only when the power of the apparatus main body is turned off, but also when the position of the drum shaft is not changed, even if the stepping motor is de-energized, the position can be maintained in the same manner, so that there is no need to excite it.

  As described above, the rotational axis of the photosensitive drum 20 that rotates in pressure contact with the intermediate transfer belt 24 is inclined by a predetermined angle with respect to the direction orthogonal to the belt traveling direction, thereby generating a shifting force on the traveling intermediate transfer belt 24. , Belt deviation correction can be performed stably.

In this reference example , a color printer in which four photosensitive drums 20 are arranged has been described as an example. However, the number of the photosensitive drums 20 is not limited to four, and may be, for example, a printer that uses a single photosensitive drum for a single color. In a printer having a plurality of photosensitive drums, the inclination of the photosensitive drums may be controlled by controlling the inclinations of all the photosensitive drums, or a single or arbitrary photosensitive drum. The inclination may be controlled. However, in the case of a printer having a plurality of photosensitive drums, if all the photosensitive drums are tilted by the same amount, there will be no color shift due to the tilt of the image, so it is desirable to tilt all the photosensitive drums by the same amount.

Furthermore, the deviation control of the intermediate transfer belt 24 may be performed only by the inclination control of the photosensitive drum described in this reference example , instead of the stretched roller. However, since the component force F1 acting in the direction orthogonal to the traveling direction of the intermediate transfer belt by tilting the photosensitive drum is minute, the parallelism error of each roller stretching the intermediate transfer belt, the cylindricity of each roller, It is desirable that the difference in circumferential length between the front side and the back side of the belt body is more accurate.

Furthermore, in the present reference example , the position of the bearing 204 is precisely moved by the double screw mechanism, but the present invention is not limited to this, and may be moved by, for example, a cam.

In this reference example , the deviation of the belt can be corrected by changing the inclination of the photosensitive drum 20 in accordance with the deviation amount of the intermediate transfer belt 24.

Further, when the belt shift control is performed, the shift control can be stabilized without the pressure contact between the photosensitive drum 20 and the intermediate transfer belt 24 preventing the shift control. In the image forming apparatus in which the photosensitive drum 20 is driven to rotate while being pressed against the intermediate transfer belt 24, the pressing force of the photosensitive drum 20 to the intermediate transfer belt 24 is strong in order to reliably perform the driven rotation. Therefore, belt deviation control becomes more difficult, but according to this reference example , there is no influence of restraint due to the pressure contact force of the photosensitive drum 20, so that deviation control is stabilized.

First Embodiment
Next, an apparatus according to the first embodiment of the present invention will be described with reference to FIGS. Note that the basic configuration of the apparatus of the present embodiment is the same as that of the above-described reference example, and thus redundant description is omitted. Here, the configuration and operation for tilting the photosensitive drum 20 that characterizes the present embodiment will be described. . Further, members having the same functions as those of the reference example described above are denoted by the same reference numerals.

  In FIG. 5, the intermediate transfer belt 24 runs in the clockwise direction as the driving roller 27 rotates in the direction of the arrow. One end of the photosensitive drum shaft 203 is rotatably supported by a bearing 204, and the bearing 204 is fixed to the arm 211. The arm 211 is swingable about a fulcrum 212 positioned vertically below the photosensitive drum 20, and also supports an LED unit 22 that is an exposure unit for forming an electrostatic latent image on the photosensitive drum 20. . A swing drive unit is connected to the extension 211a of the arm 211, and the arm 211 is swung around the fulcrum 212 by driving the swing drive unit. Thus, an exposure means moving means is configured in which the LED unit 22 moves in conjunction with the inclination of the photosensitive drum 20.

  Here, the inclination of exposure by the photosensitive drum 20 and the LED unit 22 will be described with reference to the drawings. FIG. 6 is a schematic perspective view showing how the photosensitive drum 20 is exposed, and FIG. 7 is a top view thereof. The photoconductive drum 20 at the position a is a non-tilted photoconductive drum, and the photoconductive drum 20 at the position b tilts the rotation axis by α [°] with respect to the direction perpendicular to the belt running direction. Indicates the state.

  When the photosensitive drum 20 is not tilted, the line L (Exp) exposed by the LED unit 22 becomes L (Tr) when it is rotated and transferred at a position in contact with the intermediate transfer belt 24. On the other hand, when the photosensitive drum 20 is inclined by α [°], the transfer line L (Tr) is inclined by 2α [°], which is twice α [°]. Since the image recorded on the recording sheet has an inclination at the transfer position, this angle is preferably set to 0 [°]. Therefore, when the photosensitive drum 20 is inclined by α [°], the line L (Exp) may be inclined by 2α [°] so that the inclination at the time of transfer to the belt becomes 0 °. Therefore, in this embodiment, the LED unit 22 is configured to move twice as much as the movement amount of the photosensitive drum 20.

  FIG. 8 is a diagram in which the cross sections of the inclined photosensitive drum 20 on the far side and the near side in the longitudinal direction are overlapped. As shown by the two-dot chain line, the distance on the right side is shown. The drum cross section is shown.

  Note that the amount α [°] by which the photosensitive drum 20 is tilted is very small, and it is necessary to accurately move the exposure line L (Exp) by an amount twice this α [°]. Therefore, in this embodiment, the distance m from the fulcrum 212 of the arm 211 to the support portion of the LED unit 22 is twice the distance n from the fulcrum 212 to the drum shaft 203 that is the support portion of the photosensitive drum 20. It is set. As a result, the inclination of the LED unit 22 when the photosensitive drum 20 is tilted by swinging the arm 211 about the fulcrum 212, that is, the inclination of the line L (Exp) is twice the inclination of the photosensitive drum 20. can do.

  In the present embodiment, the case where the LED unit 22 is positioned substantially vertically above has been described as an example. However, the present embodiment is not limited to this. For example, as shown in FIG. 9, the present embodiment can be applied even if the LED unit 22 is not vertically above. However, when the arm 211 is swung, the photosensitive drum Therefore, it is desirable that the LED unit, that is, the exposure position be arranged vertically upward (on the opposite side of the transfer). Alternatively, an arrangement as shown in FIG. 10 in which the swing fulcrum is arranged vertically downward may be used.

  More preferably, the swing fulcrum 212 is disposed on a line that passes vertically downward, that is, a position passing through the position where the photosensitive drum 20 and the intermediate transfer belt 24 are in pressure contact with the center of the photosensitive drum shaft 203. With this arrangement, the vertical displacement of the photosensitive drum shaft when the arm 211 is swung is minimized, that is, the influence on the pressure contact condition between the photosensitive drum 20 and the intermediate transfer belt 24 is minimized. .

  In the present embodiment, as described above, by moving the latent image writing position in accordance with the tilt of the drum, it is possible to provide an image with no tilt of the image.

  Further, the swinging fulcrum of the swinging member that supports the photosensitive drum 20 and the LED unit 22 that is the exposure means has a simple ratio by setting the ratio of the distance from the fulcrum to each support position to be approximately 1: 2. Thus, it is possible to provide an image without tilting the image by reliably moving the exposure position.

[ Second Embodiment]
Next, an apparatus according to the second embodiment will be described with reference to FIG. The basic configuration of the apparatus according to the present embodiment is also the same as that of the above-described embodiment, and thus redundant description is omitted. Here, a configuration that is a feature of the present embodiment will be described. Moreover, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.

  In the above-described embodiment, the LED unit 22 as an exposure apparatus is disposed above the photosensitive drum 20, but in the present embodiment, the LED unit 22 is disposed on the left side of the photosensitive drum 20. Further, the swinging fulcrum 212 of the arm 211 is disposed on a line passing through the position where the photosensitive drum 20 and the intermediate transfer belt 24 are in pressure contact with the center of the photosensitive drum shaft 203.

  By swinging the arm 211, the photosensitive drum 20 is tilted in the same manner as in the previous embodiment. At this time, when the photosensitive drum 20 is tilted, the position in contact with the intermediate transfer belt 24 is tilted, but at the same time, the exposure position by the LED unit 22 is also changed. Here, since the distance n from the fulcrum 212 to the photosensitive drum shaft 203 and the distance L from the photosensitive drum shaft 203 to the oscillating fulcrum of the oscillating member that supports the LED unit 22 are arranged equally, Since the inclination of the position where the photosensitive drum is exposed by the same amount in the opposite direction to the inclination of the position is generated, an image having no image inclination can be provided.

[ Third Embodiment]
Next, an apparatus according to a third embodiment will be described with reference to FIG. The basic configuration of the apparatus according to the present embodiment is also the same as that of the above-described embodiment, and thus redundant description is omitted. Here, a configuration that is a feature of the present embodiment will be described. Moreover, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.

  In the above-described embodiment, an example in which the photosensitive drum 20 is tilted as a member that rotates while being pressed against the intermediate transfer belt 24 to correct the belt is illustrated. However, in this embodiment, the primary transfer roller 25 is inclined instead of the photosensitive drum 20 to generate the force F in order to generate a shifting force in the direction in which the intermediate transfer belt 24 is desired to move (direction of arrow B). ing.

  As shown in FIG. 12, in order to press the intermediate transfer belt 24 against the photosensitive drum 20, the front side of the primary transfer roller 25 is moved in the direction of arrow C (parallel to the running direction of the intermediate transfer belt), and the primary transfer roller The 25 rotation shafts are inclined by a predetermined angle with respect to the direction orthogonal to the belt running direction. The configuration of the transfer roller tilt changing means for tilting the primary transfer roller may be the same as the configuration of the tilt changing means for tilting the photosensitive drum 20 in the above-described embodiment.

  By tilting the primary transfer roller 25, the intermediate transfer belt 24 receives a force in the tangential direction of the primary transfer roller 25 and generates a force in the shift direction as in the case where the photosensitive drum 20 is tilted.

  Note that if the primary transfer roller 25 is extremely inclined, the primary transfer performance may be affected, and even if the inclination is small, the intermediate transfer belt 24 can be sufficiently controlled stably. The amount by which the roller 25 is inclined is preferably 1 [°] or less.

  Thus, by changing the inclination of the primary transfer roller 25 in accordance with the amount of deviation of the belt body, the pressure contact between the primary transfer roller 25 and the intermediate transfer belt 24 does not hinder the deviation control, and the deviation control is stabilized.

[ Fourth Embodiment]
Next, an apparatus according to a fourth embodiment will be described. The basic configuration of the apparatus according to the present embodiment is also the same as that of the above-described embodiment, and thus redundant description is omitted. Here, a configuration that is a feature of the present embodiment will be described. Moreover, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above.

  In the above-described embodiment, the example in which the photosensitive drum 20 or the primary transfer roller 25 is tilted to correct the deviation of the belt has been described. However, in the present embodiment, the deviation of the belt is corrected by inclining both the photosensitive drum 20 and the primary transfer roller 25.

  In other words, both the photosensitive drum 20 and the primary transfer roller 25 are provided with inclination changing means for inclining the rotation shaft with respect to the belt traveling direction. Then, the photosensitive drum 20 and the primary transfer roller 25 are both tilted according to the detection signal of the belt end detection sensor 201, and the intermediate transfer belt 24 is stably run.

  According to the present embodiment, there is no change in the pressure contact state of the photosensitive drum 20 to the intermediate transfer belt 24 by the primary transfer roller 25. Therefore, a good image can be formed without affecting the primary transfer performance.

[Other Embodiments]
In the above-described embodiment, the toner image formed on the photosensitive drum is primarily transferred to the intermediate transfer belt, which is a belt body, and the primary transfer image is secondarily transferred to the recording sheet in the secondary transfer portion to form a color image. The forming apparatus has been described. However, the belt body may be a conveyance belt that conveys a recording sheet as a recording medium.

  In other words, a conveyance belt that conveys a recording sheet is opposed to a photosensitive drum that is an image carrier, and the toner image formed on the photosensitive drum is transferred to a recording sheet that is conveyed by the conveyance belt. An image forming apparatus that forms an image may be used. In this case as well, the deviation of the belt can be corrected by tilting the photosensitive drum or the primary transfer roller that rotates while being pressed against the belt.

FIG. 6 is a perspective view of an intermediate transfer belt and a photosensitive drum for explaining a reference example . FIG. 6 is a top view of an intermediate transfer belt and a photosensitive drum for explaining a reference example . It is a front view of a photosensitive drum shaft support part. FIG. 3 is a main cross-sectional view of a printer according to a reference example . A photosensitive drum and a perspective view with the intermediate transfer belt for explaining the first embodiment. It is a perspective view which shows the mode of exposure of a photoconductive drum. It is an upper view which shows the mode of exposure of a photoconductor drum. It is a front view which shows the mode of exposure of a photoconductor drum. It is a front view which shows the mode of exposure of a photoconductor drum. It is a front view which shows the mode of exposure of a photoconductor drum. FIG. 6 is a perspective view illustrating an intermediate transfer belt, a photosensitive drum, and a second embodiment. FIG. 10 is an intermediate transfer belt, a photosensitive drum, and a perspective view illustrating a third embodiment.

P: Recording sheet 1: Printer body 2 ... Image forming unit 4 ... Sheet conveying unit
20… Photoconductor drum
21… Charger
22… LED unit
24… Intermediate transfer belt
25… Primary transfer roller
26… cleaner
27… Drive roller
28 ... Secondary transfer inner roller
29… Tension roller
40 ... sheet cassette
41… feed roller
42 Separating roller pair
43… Conveying roller
44… Registration roller pair
45 ... Secondary transfer outer roller
46… Conveyor belt
47… Fixing device
48… discharge roller
49… discharge tray
201… belt end detection sensor
202… Oscillating motor
203… Photoreceptor drum shaft
204… Bearing
205… Holder
206… Compression spring
207… Pressure head
208… Double screw mechanism
209… Outer ring
210… Stepping motor
211… Arm
211a ... Extension part
212… fulcrum

Claims (7)

In an image forming apparatus for forming an image by transferring an image formed on a rotating image carrier to a recording medium conveyed by the belt member directly or on a belt member that is in pressure contact with the image carrier.
A deviation detecting means for detecting a deviation of the belt body when traveling;
A transfer roller that is driven to rotate in pressure contact with the belt member so as to face the image bearing member,
An inclination changing means for changing an inclination of the transfer roller with respect to a running direction of the belt body according to a detection result by the deviation detecting means;
An image forming apparatus comprising: In an image forming apparatus for forming an image by transferring an image formed on a rotating image carrier to a recording medium conveyed by the belt member directly or on a belt member that is in pressure contact with the image carrier.
A deviation detecting means for detecting a deviation of the belt body when traveling;
A transfer roller that is driven to rotate in pressure contact with the belt member so as to face the image bearing member,
Changing means for changing the inclination of the image carrier and the transfer roller with respect to the running direction of the belt body according to the detection result by the deviation detecting means;
An image forming apparatus comprising: 2. An exposure means moving means for moving an exposure means for irradiating light according to image information in association with an inclination of the image carrier to form an electrostatic latent image on the image carrier. the image forming apparatus according to 2. In an image forming apparatus for forming an image by transferring an image formed on a rotating image carrier to a recording medium conveyed by the belt member directly or on a belt member that is in pressure contact with the image carrier.
A deviation detecting means for detecting a deviation of the belt body when traveling;
An inclination changing means for changing an inclination of the image carrier with respect to a running direction of the belt body according to a detection result by the deviation detecting means;
Exposure means moving means for moving exposure means for irradiating light according to image information to form an electrostatic latent image on the image carrier in conjunction with the inclination of the image carrier;
An image forming apparatus comprising: The image carrier and the exposure means are supported by a support member that can swing around a fulcrum,
5. The image forming apparatus according to claim 3, wherein a distance from the fulcrum to the support portion of the exposure unit is twice a distance from the fulcrum to the support portion of the image carrier. The image carrier and the exposure unit are supported by a support member that can swing around a fulcrum disposed in the vicinity of a pressure contact portion between the image carrier and the belt body,
5. The image forming apparatus according to claim 3 , wherein a distance from the fulcrum to the support portion of the image carrier is equal to a distance from the support portion of the image carrier to the exposure unit.   7. The image forming apparatus according to claim 1, wherein the image carrier is driven in pressure contact with the traveling belt body. 8.

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