JP6164522B2 - Belt device and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a composite machine thereof, and a belt device installed therein, in particular, an intermediate transfer belt, a transfer conveyance belt, The present invention relates to a belt device that corrects meandering of a belt member such as a photosensitive belt, and an image forming apparatus.

2. Description of the Related Art Conventionally, in image forming apparatuses such as copying machines and printers, tandem type color image forming apparatuses provided with an intermediate transfer belt (belt apparatus) are known (for example, see Patent Documents 1 to 3).
Specifically, four photosensitive drums (image carriers) are arranged side by side so as to face the intermediate transfer belt (belt member). On these four photosensitive drums, black (black), yellow, magenta, and cyan toner images are formed, respectively. Then, the toner images of the respective colors formed on the respective photoconductive drums are transferred onto the intermediate transfer belt in an overlapping manner. Further, the toner images of a plurality of colors carried on the intermediate transfer belt are transferred onto a recording medium as a color image.

In such an image forming apparatus, a technique for detecting the position (displacement) of the end portion in the width direction of the intermediate transfer belt and correcting the meandering (displacement in the width direction) of the intermediate transfer belt based on the detection result is known. (For example, refer to Patent Documents 1 to 3.)
Specifically, in Patent Document 1 and the like, a displacement sensor detects a displacement amount of a contact that abuts on an end portion in the width direction of an intermediate transfer belt (endless belt) and swings following the displacement. Based on the detection result of the displacement sensor, the displacement (meandering) of the intermediate transfer belt is corrected by the meandering correction roller. More specifically, the transfer member (swinging arm) connected to the meandering correction roller that stretches the intermediate transfer belt is swung by the operation of the eccentric cam, so that the inclination of the rotation shaft of the meandering correction roller is varied to perform the intermediate transfer. Corrects the meandering of the belt.
In Patent Document 2, etc., the position of the end portion in the width direction of the intermediate transfer belt is detected directly or indirectly by an optical sensor. The displacement (meandering) of the intermediate transfer belt is corrected by the steering roller based on the detection result of the optical sensor. Specifically, a roller holder (swing plate) that holds one end of the meandering correction roller that stretches the intermediate transfer belt is swung by the action of a wire that is stretched by a take-up pulley, so that the rotating shaft of the steering roller is rotated. The meandering of the intermediate transfer belt is corrected by varying the inclination.

  In the conventional image forming apparatus described above, when the intermediate transfer belt is warped or bent in the vicinity of the detection means (displacement sensor or optical sensor) for detecting the position (displacement) of the end portion in the width direction of the intermediate transfer belt. Therefore, the position of the end portion in the width direction of the intermediate transfer belt cannot be accurately detected by the detecting means, and the accuracy of meandering correction of the intermediate transfer belt may be lowered.

  Such a problem is not limited to a belt device using an intermediate transfer belt as a belt member, and a belt device using a transfer conveyance belt as a belt member, as long as the belt device performs meandering correction of the belt member, The same applies to a belt apparatus using a photosensitive belt as a belt member.

  The present invention has been made to solve the above-mentioned problems, and the belt member is warped or bent, and the position of the belt member in the width direction cannot be accurately detected by the detecting means. It is an object of the present invention to provide a belt device and an image forming apparatus that can alleviate the disadvantages and can surely correct the meandering of the belt member.

A belt device according to a first aspect of the present invention is a belt member that is stretched around a plurality of roller members, travels in a predetermined traveling direction, and an image is transferred to the surface thereof, and the belt member A detecting means for urging the belt member to detect a position of the width direction end of the belt member, and based on a detection result of the detecting means. Correction means for correcting the meandering of the belt member by varying the inclination of the rotation axis of one of the plurality of roller members, and a position corresponding to an end in the width direction of the belt member, the detection means And a pressing member that is installed in a non-image area at a nearby position and holds the warp or / and bending of the belt member .

  In the present invention, since the position corresponding to the end portion in the width direction of the belt member is in the vicinity of the detection means, and the non-image area is provided with a pressing member that holds the warp or the deflection of the belt member. The problem that the warp or the flexure of the belt member occurs and the position of the belt member in the width direction cannot be accurately detected by the detecting means is alleviated, and the meandering correction of the belt member is reliably performed. A belt device and an image forming apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an image forming unit in the image forming apparatus of FIG. 1. FIG. 2 is a configuration diagram illustrating a belt device installed in the image forming apparatus of FIG. 1. It is the schematic which looked at a part of belt device in the width direction. It is a schematic perspective view which shows the vicinity of a detection part. It is a perspective view which shows the vicinity of a detection part. It is a perspective view which shows the relationship between the pressing member with respect to a housing | casing, and a detection part. It is the schematic perspective view which looked at the vicinity of the correction roller from the back side. It is the perspective view which looked at the vicinity of the correction roller from the back side. It is a perspective view which shows the vicinity of a drive pulley. It is the schematic perspective view which looked at the vicinity of the correction roller from the near side. It is a perspective view which shows the adjustment means of another form. It is the schematic which shows the vicinity of a detection part. It is a perspective view which shows the relationship between the detection part and pressing member of another form. It is the schematic which shows the vicinity of the detection part in the belt apparatus as the modification 1. It is the schematic which looked at the subunit in the belt apparatus as the modification 2 in the width direction. It is the figure which looked at the subunit of another form in the width direction. It is an enlarged view which shows the principal part of the subunit of FIG. It is the figure which looked at the principal part of the subunit of another form in the width direction. It is an enlarged view which shows the principal part of the subunit of FIG. It is a perspective view which shows the vicinity of the pressing member in the belt apparatus as the modification 3.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIGS.
FIG. 1 is a block diagram showing a printer as an image forming apparatus, and FIG. 2 is an enlarged view showing an image forming unit thereof.
As shown in FIG. 1, an intermediate transfer belt device 15 as a belt device is installed in the center of the image forming apparatus main body 100. Further, image forming portions 6Y, 6M, 6C, and 6K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 8 (belt member) of the intermediate transfer belt device 15. Yes.

  Referring to FIG. 2, an image forming unit 6Y corresponding to yellow includes a photosensitive drum 1Y as an image carrier, a charging unit 4Y disposed around the photosensitive drum 1Y, a developing unit 5Y, and a cleaning unit 2Y. , And a static elimination unit (not shown). Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

  The other three image forming units 6M, 6C, and 6K have substantially the same configuration as that of the image forming unit 6Y corresponding to yellow except that the color of the toner used is different. A corresponding image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

Referring to FIG. 2, photoconductor drum 1Y is rotated counterclockwise by a drive motor (not shown). Then, the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (a charging process).
Thereafter, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure unit 7, and an electrostatic latent image corresponding to yellow is formed by exposure scanning at this position (in the exposure process). is there.).

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the developing portion 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image (developing process).
Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the intermediate transfer belt 8 (belt member) and the transfer roller 9Y, and the toner image on the photosensitive drum 1Y is transferred onto the intermediate transfer belt 8 at this position. (This is a primary transfer process.) At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photosensitive drum 1Y at this position is collected in the cleaning unit 2Y by the cleaning blade 2a (cleaning). Process.)
Finally, the surface of the photosensitive drum 1Y reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1 is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

The image forming process described above is performed in the other image forming units 6M, 6C, and 6K in the same manner as the yellow image forming unit 6Y. That is, a laser beam L based on image information is irradiated from the exposure unit 7 disposed above the image forming unit onto the photosensitive drums 1M, 1C, and 1K of the image forming units 6M, 6C, and 6K. Is done. Specifically, the exposure unit 7 emits laser light L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven.
Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

  Here, the intermediate transfer belt device 15 (belt device) includes an intermediate transfer belt 8, four transfer rollers 9Y, 9M, 9C, and 9K, a driving roller 12A, a secondary transfer counter roller 12B, a tension, with reference to FIG. The roller 12 </ b> C, the correction roller 13, the movable roller 11, the cleaning counter roller 14, the detection unit 80, a pressing member 88 (pressing member), the intermediate transfer cleaning unit 10, and the like. The intermediate transfer belt 8 is stretched and supported by a plurality of roller members 11, 12A to 12C, 13, and 14, and is endlessly moved in the direction of the arrow in FIG. 3 by the rotational drive of one roller member (drive roller) 12A. Is done.

The four transfer rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 between the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. Then, a transfer voltage (transfer bias) opposite to the polarity of the toner is applied to the transfer rollers 9Y, 9M, 9C, and 9K.
The intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the transfer rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer counter roller 12B sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a recording medium P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is removed.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed. The configuration and operation of the intermediate transfer belt device 15 as a belt device will be described in more detail later with reference to FIGS.

Here, referring to FIG. 1, the recording medium P transported to the position of the secondary transfer nip is fed to the paper feeding unit 26 (or laterally fed) disposed below the apparatus main body 100. From the paper section) via the paper feed roller 27, the registration roller pair 28, and the like.
Specifically, a plurality of recording media P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is driven to rotate counterclockwise in FIG. 1, the uppermost recording medium P is fed toward the rollers of the registration roller pair 28.

  The recording medium P conveyed to the registration roller pair 28 (timing roller pair) temporarily stops at the position of the roller nip of the registration roller pair 28 whose rotation driving has been stopped. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the recording medium P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the recording medium P.

Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred on the surface is fixed on the recording medium P by heat and pressure generated by the fixing roller and the pressure roller.
Thereafter, the recording medium P is discharged out of the apparatus by a pair of discharge rollers (not shown). The recording medium P discharged out of the apparatus by the pair of paper discharge rollers is sequentially stacked on the stack unit as an output image.
Thus, a series of image forming processes in the image forming apparatus is completed.

Next, the configuration and operation of the developing unit in the image forming unit will be described in more detail with reference to FIG.
The developing unit 5Y includes a developing roller 51Y that faces the photosensitive drum 1Y, a doctor blade 52Y that faces the developing roller 51Y, two transport screws 55Y disposed in the developer containing unit, and an opening in the developer containing unit. A toner replenishment path 43Y that communicates with each other via a toner density, a density detection sensor 56Y that detects a toner density in the developer, and the like. The developing roller 51Y includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. In the developer accommodating portion, a two-component developer composed of a carrier and toner is accommodated.

The developing unit 5Y configured as described above operates as follows.
The sleeve of the developing roller 51Y rotates in the direction of the arrow in FIG. The developer carried on the developing roller 51Y by the magnetic field formed by the magnet moves on the developing roller 51Y as the sleeve rotates. Here, the developer in the developing device 5Y is adjusted so that the toner ratio (toner concentration) in the developer is within a predetermined range.
Thereafter, the toner replenished in the developer accommodating portion circulates through the two separated developer accommodating portions while being mixed and stirred together with the developer by the two conveying screws 55Y (movement in the direction perpendicular to the paper surface of FIG. 2). .) The toner in the developer is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

  The developer carried on the developing roller 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. The developer on the developing roller 51Y is conveyed to a position facing the photosensitive drum 1Y (development area) after the developer amount is made appropriate at this position. The toner is attracted to the latent image formed on the photosensitive drum 1Y by the electric field formed in the development area. Thereafter, the developer remaining on the developing roller 51Y reaches the upper portion of the developer accommodating portion as the sleeve rotates, and is detached from the developing roller 51Y at this position.

Next, the intermediate transfer belt device 15 (belt device) in the present embodiment will be described in detail with reference to FIGS.
FIG. 3 is a configuration diagram showing an intermediate transfer belt device 15 as a belt device. 4A is a schematic top view of a portion of the intermediate transfer belt device 15 as viewed in the width direction, and FIG. 4B is a schematic side view of a portion of the intermediate transfer belt device 15 as viewed in the width direction. . FIG. 5 is a schematic perspective view schematically showing the vicinity of the detection unit 80 in the intermediate transfer belt device 15. FIG. 6 shows the vertical relationship between the detection unit 80 and the intermediate transfer belt 8 for easy understanding. It is shown in reverse with respect to the one. 6 is a perspective view showing the vicinity of the detection unit 80 (the illustration of the holding member 88 is omitted), and FIG. 7 is a perspective view showing the relationship between the holding member 88 and the detection unit 80 with respect to the housing 90. FIG. FIG. 8 is a schematic view of the vicinity of the correction roller 13 (correction means) in the intermediate transfer belt device 15 as viewed from the back side, and a part of the perspective view is schematically shown as a plan view. FIG. 9 is a perspective view of the vicinity of the correction roller 13 as seen from the back side. FIG. 10 is a perspective view showing the vicinity of a drive pulley 38 as a drive source for swinging the swing arm 31. FIG. 11 is a schematic perspective view of the vicinity (adjusting means) of the correction roller 13 as seen from the front side. FIG. 12 is a perspective view showing another form of adjusting means, and is a perspective view of the vicinity of the correction roller 13 as seen from the front side.
13A1 is a schematic cross-sectional view showing the vicinity of the detection unit 80 in the width direction when the pressing member 88 is installed, and FIG. 13B1 is a case where the pressing member 88 is not installed. It is a schematic sectional drawing which shows the vicinity of the detection part 80 in the width direction. Further, FIG. 13A2 is a schematic side view showing the vicinity of the detection unit 80 along the traveling direction of the intermediate transfer belt 8 when the pressing member 88 is installed, and FIG. FIG. 6 is a schematic side view showing the vicinity of a detection unit 80 along the traveling direction of the intermediate transfer belt 8 when a member 88 is not installed.
In each drawing, the illustration of each member is appropriately simplified or schematically illustrated for the sake of simplicity, such as the intermediate transfer belt 8 being shown in a rectangular shape.

  3 and 4, the intermediate transfer belt device 15 (belt device) includes an intermediate transfer belt 8 as a belt member, four transfer rollers 9Y, 9M, 9C, and 9K, a driving roller 12A, and a secondary transfer counter. A roller 12B, a tension roller 12C, a correction roller 13 as a correction unit, a movable roller 11, a cleaning counter roller 14, a detection unit 80 as a detection unit, a pressing member 88 (pressing member), an intermediate transfer cleaning unit 10, and the like. Is done.

  The intermediate transfer belt 8 as a belt member is disposed so as to face the photosensitive drums 1Y, 1M, 1C, and 1K as four image carriers that respectively carry toner images of respective colors. The intermediate transfer belt 8 is stretched and supported mainly by six roller members (a driving roller 12A, a secondary transfer counter roller 12B, a tension roller 12C, a movable roller 11, a correction roller 13, and a cleaning counter roller 14). ing.

In the present embodiment, the intermediate transfer belt 8 includes PVDF (vinylidene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), etc. in a single layer or multiple layers. A conductive material such as carbon black is dispersed. The intermediate transfer belt 8 is adjusted so that the volume resistivity is in the range of 10 ⁷ to 10 ¹² Ωcm, and the surface resistivity on the back side of the belt is in the range of 10 ⁸ to 10 ¹² Ωcm. The intermediate transfer belt 8 is set to have a thickness in the range of 80 to 100 μm. In the present embodiment, the thickness of the intermediate transfer belt 8 is set to 90 μm.
If necessary, a release layer can be coated on the surface of the intermediate transfer belt 8. At that time, materials used for the coating are ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PVDF (vinylidene fluoride), PEA (perfluoroalkoxy fluororesin), FEP (four A fluororesin such as fluorinated ethylene-hexafluoropropylene copolymer) or PVF (vinyl fluoride) can be used, but is not limited thereto.
Further, as a method for manufacturing the intermediate transfer belt 8, there are a casting method, a centrifugal molding method, and the like, and a step of polishing the surface is performed as necessary.

  The transfer rollers 9Y, 9M, 9C, and 9K are opposed to the corresponding photosensitive drums 1Y, 1M, 1C, and 1K through the intermediate transfer belt 8, respectively. More specifically, the yellow transfer roller 9Y faces the yellow photosensitive drum 1Y via the intermediate transfer belt 8, and the magenta transfer roller 9M contacts the magenta photosensitive drum 1M via the intermediate transfer belt 8. The cyan transfer roller 9C faces the cyan photosensitive drum 1C via the intermediate transfer belt 8, and the black (black) transfer roller 9K passes through the intermediate transfer belt 8 for black (black). For example).

The movable roller 11 is held by a holding member (not shown) together with the four transfer rollers 9Y, 9M, 9C, and 9K, and separates the intermediate transfer belt 8 from the photosensitive drums 1Y, 1M, 1C, and 1K. It is configured as follows.
Specifically, the movable roller 11 moves together with the four transfer rollers 9Y, 9M, 9C, and 9K downward in FIG. 3, so that the intermediate transfer belt 8 is separated from the photosensitive drums 1Y, 1M, 1C, and 1K. The operation of separating the intermediate transfer belt 8 from the photosensitive drums 1Y, 1M, 1C, and 1K is performed to reduce wear deterioration of the intermediate transfer belt 8, and is performed at the time of non-image formation or the like. It is. Although not shown, when a monochrome image is formed, the movable roller 11 moves downward together with the three color transfer rollers 9Y, 9M, and 9C, so that the intermediate transfer belt 8 is moved to the black photosensitive drum 1K. Contact only.

The drive roller 12A is rotationally driven by a drive motor (not shown). As a result, the intermediate transfer belt 8 travels in a predetermined traveling direction (clockwise in FIG. 3).
The secondary transfer counter roller 12 </ b> B is in contact with the secondary transfer roller 19 through the intermediate transfer belt 8. The tension roller 12 </ b> C is in contact with the outer peripheral surface of the intermediate transfer belt 8. An intermediate transfer cleaning unit 10 (cleaning blade) is installed between the secondary transfer counter roller 12B and the tension roller 12C so as to oppose the cleaning counter roller 14 via the intermediate transfer belt 8.

Here, in the intermediate transfer belt device 15 according to the present exemplary embodiment, a detection unit 80 is installed as a detection unit that detects the displacement of the intermediate transfer belt 8 in the width direction (the vertical direction in FIG. 3). Yes. In other words, the detection unit 80 serving as a detection unit is installed at a position corresponding to the end in the width direction of the intermediate transfer belt 8 and detects the position of the end in the width direction of the intermediate transfer belt 8.
Specifically, referring to FIG. 5 (and FIGS. 6 and 7), the detection unit 80 includes a swing member 82 provided with a contact portion 82a that contacts the end portion in the width direction of the intermediate transfer belt 8, and swings. An optical sensor 81 (photo sensor) that detects the amount of displacement of the member 82, a spring 83 (biasing member) that biases the swinging member 82 (abutting portion 82a) in a direction to abut against the intermediate transfer belt 8, and the like. It is configured.

The swing member 82 includes a contact portion 82a, a rotation support shaft 82b, an arm portion 82c, and the like. The abutting portion 82a is a substantially columnar member, abutting so that the center portion abuts against the end portion (end surface) in the width direction of the intermediate transfer belt 8, and the base portion is on one end side of the arm portion 82c. It is fixed. The rotation support shaft 82b is rotatably supported by the housing 90 of the intermediate transfer belt device 15. The arm portion 82c is formed in a substantially boomerang shape, and a rotation support shaft 82b is formed at the center thereof. A slit 82c1 (opening) is formed on the other end side of the arm portion 82c. Further, one end of a spring 83 is connected between the slit 82c1 and the rotation support shaft 82b in the arm portion 82c. The other end of the spring 83 is connected to the housing 90.
With such a configuration, the swinging member 82 swings following the displacement in the width direction of the intermediate transfer belt 8 (closer to the belt in the direction indicated by the broken line in FIG. 5) (FIG. 5). (It is a swing in the direction of the solid double arrow in the middle.) In the present embodiment, the intermediate transfer belt 8 is set to travel at about 400 mm / second in the traveling direction (in the direction of the arrow in FIG. 5).

  And the optical sensor 81 is installed so that the position of the slit 82c1 of the arm part 82c in the rocking | swiveling member 82 may be pinched | interposed (it is fixed to the housing | casing 90). The optical sensor 81 is mainly composed of a light emitting element that is spaced above the arm portion 82c (slit 82c1) in FIG. 5 and a light receiving element that is spaced below the arm portion 82c (slit 82c1) in FIG. And an element. The light emitted from the light emitting element enters the light receiving element through the slit 82c. At this time, the arm portion 82c rotates around the rotation support shaft 82b, so that the position of the slit 82c1 facing the optical sensor 81 changes, and the amount of light incident on the light receiving element changes and is proportional thereto. Thus, the output value of the light receiving element (optical sensor 81) changes. Thereby, the displacement amount in the width direction of the intermediate transfer belt 8 (the position of the end portion in the width direction) can be detected.

  Here, as shown in FIG. 5, the intermediate transfer belt 8 is warped or bent at a position corresponding to the end portion in the width direction of the intermediate transfer belt 8 and in the vicinity of the detection unit 80 serving as detection means. A holding member 88 for holding (regulating) is provided, which will be described in detail later.

When the displacement (displacement amount) of the intermediate transfer belt 8 is detected by the detection unit 80, the displacement in the width direction of the intermediate transfer belt 8 is corrected by the correction roller 13 (correction units 31 to 39) based on the detection result. Is done. When the meandering of the intermediate transfer belt 8 cannot be corrected within a predetermined time (when the detection result of the detection unit 80 does not change within the predetermined range), an abnormality has occurred in the meandering correction in terms of control. The operation of the apparatus is stopped.
Here, referring to FIG. 3, the correction roller 13 is on the upstream side in the running direction of the intermediate transfer belt 8 with respect to the photosensitive drums 1 </ b> Y, 1 </ b> M, 1 </ b> C, and 1 </ b> K, and on the inner peripheral surface of the intermediate transfer belt 8. It arrange | positions so that it may contact | connect. 4 and 8, the correction roller 13 swings the swing arm 31 by the winding / relaxing operation of the wire 33, thereby causing the swing roller W (the frame 70 via the adjustment member 67 to rotate). ) And the X1 and X2 directions (up and down directions).
With this configuration, when the intermediate transfer belt 8 is displaced to the right (belt side) in FIG. 4A, the correction roller 13 is swung in the X1 direction based on the detection result, and the intermediate transfer belt 8 is moved. Displacement correction (meander correction) is performed. In contrast, when the intermediate transfer belt 8 is displaced to the left in FIG. 4A, the correction roller 13 is swung in the X2 direction based on the detection result, and the displacement correction (meander correction) of the intermediate transfer belt 8 is performed. ) Is performed. As a result, problems such as the intermediate transfer belt 8 running meandering, and the intermediate transfer belt 8 being greatly displaced in the width direction (close to the belt) and contacting other members to damage the intermediate transfer belt 8 are suppressed. The

Hereinafter, the configuration and operation of the correction units 31 to 39 (meandering correction mechanism) in the intermediate transfer belt device 15 will be described in detail with reference to FIGS.
The correction means 31 to 39 (meandering correction mechanism) have one end side (the right side in FIG. 4 and the front side (operation side) of the apparatus) of the correction roller 13 as a fixed end and the other end side (in FIG. 4). By moving the left side and the back side of the apparatus in the forward and backward direction (up and down direction), the meandering of the intermediate transfer belt 8 is corrected by varying the inclination of the rotation shaft of the correction roller 13. 4 and 8, the meandering correction mechanism includes a correction roller 13 (one of a plurality of roller members that stretch the intermediate transfer belt 8), a swing arm 31, a tension spring 35, It comprises a wire holding pulley 32, a wire 33, a wire relay pulley 36, a two-stage pulley 37, a driving pulley 38, a timing belt 39, and the like.

The swing arm 31 is a metal plate connected to the shaft portion 13 b (the shaft portion on the other end side) of the correction roller 13. Specifically, referring to FIG. 8, one end side of the swing arm 31 is connected to the shaft portion 13 b of the correction roller 13 via a bearing 34. A wire holding pulley 32 is held non-rotatingly on the other end side of the swing arm 31. Further, the central portion of the swing arm 31 is rotatably supported by a side plate (not shown) of the device 15 and serves as a swing center 31 b of the swing arm 31.
In the present embodiment, one end of a tension spring 35 as an urging member is connected between the shaft portion 13b (bearing 34) and the swing center 31b. The other end of the tension spring 35 is connected to the housing of the device 15.

One end of a wire 33 is connected to the wire holding pulley 32. The other end of the wire 33 is connected to the wire take-up pulley portion 37 a of the two-stage pulley 37 through the wire relay pulley 36. A timing belt 39 is wound around the belt pulley portion 37 b and the drive pulley 38 of the two-stage pulley 37. The drive pulley 38 is installed on a motor shaft of a drive motor (not shown) (a motor that can rotate in forward and reverse directions, such as a stepping motor and a DC motor). Referring to FIG. 10, the drive pulley 38 (drive motor) is fixedly installed on a holding plate 91 that is rotatably held around a support shaft 91 a with respect to the housing 90. The holding plate 91 is energized by a spring 92 (one end side hook is connected to the holding plate 91 and the other end side hook is connected to the housing 90). Tension is applied.
With such a configuration, when the drive motor is driven and the drive pulley 38 rotates, the swing arm 31 rotates in the forward / reverse direction (X1, X2 direction or M1, M2 direction in FIG. 8). As a result, the inclination of the rotation shaft of the correction roller 13 with respect to the traveling direction is varied, and the meandering of the intermediate transfer belt 8 is corrected.

Specifically, when the two-stage pulley 37 is rotated counterclockwise in FIG. 8 (and FIG. 10) by the rotational drive of the drive pulley 38, the wire 33 is a wire take-up pulley of the two-stage pulley 37 in a tensioned state. The non-rotating wire holding pulley 32 is pulled downward by being wound around the portion 37a, and the swing arm 31 is pushed down in the M1 direction (forward direction) so as to resist the urging force of the tension spring 35. As a result, the correction roller 13 moves in the X1 direction in FIG.
On the other hand, when the two-stage pulley 37 is rotated in the clockwise direction of FIG. 8 (and FIG. 10) by the rotational drive of the drive pulley 38, the wire 33 is wound from the wire winding pulley portion 37a of the two-stage pulley 37. Is released, the wire 33 is relaxed between the wire holding pulley 32 and the swing arm 31 is pushed up in the M2 direction (reverse direction) by the urging force of the tension spring 35. Thereby, the correction roller 13 moves in the X2 direction of FIG.

Referring to FIG. 9, a detected portion 93 (filler) is installed in a part of the swing arm 31, and the position detection sensor that optically detects the position of the detected portion 93 in the device 15. 94 (photo sensor) is installed. As a result, the posture of the swing arm 31 in the rotational direction can be determined, and the amount of movement of the correction roller 13 in the X1 and X2 directions can be accurately controlled.
In the present embodiment, a wire mechanism is used as the correction means for changing the inclination of the correction roller 13, but the correction means is not limited to this, and for example, a cam mechanism is used as the correction means. You can also use what you had.

Hereinafter, the configuration and operation of the adjusting means of the intermediate transfer belt device 15 in this embodiment will be described in detail with reference to FIG.
Referring to FIG. 11, an adjustment member 67 (adjustment means) as an adjustment means for adjusting the position of the fixed end is installed on the shaft portion 13 a on one end side (near side) of the correction roller 13. Specifically, the shaft portion 13 a (fixed end side shaft portion) of the correction roller 13 is rotatably supported by the frame 70 of the apparatus 15 via the adjustment member 67. The adjustment member 67 is rotatably supported by the frame 70 around the support shaft 67b. The adjustment member 67 is provided with an arc-shaped long hole 67a. Further, the frame 70 of the apparatus 15 is formed with a long hole 70a into which the fixed end side shaft portion 13a of the correction roller 13 is fitted.
With such a configuration, after the movement of the fixed end side shaft portion 13a in the Q1 and Q2 directions together with the adjustment member 67 is finished, the female screw portion of the frame 70 is inserted through the arc-shaped elongated hole 67a formed in the adjustment member 67. The position of the adjustment member 67 in the rotation direction is fixed by screwing the screw 68 to the position, thereby fixing the position of the fixed end side shaft portion 13a in the rotation direction.

The adjustment member 67 configured as described above is assembled to the intermediate transfer belt device 15 in a state where the parallelism of the plurality of roller members 11, 12A to 12C, 13, and 14 that stretch and support the intermediate transfer belt 8 is not sufficient. Or the frame 70 that rotatably supports the plurality of roller members 11, 12A to 12C, 13, and 14 is distorted, and the straightness of the plurality of roller members 11, 12A to 12C, 13, and 14 is sufficient. If the default position (reference position) of the correction roller 13 is greatly deviated in either the forward or reverse direction from the center position of the moving range due to the fact that the default position becomes the center position of the moving range. As operated manually. Mainly, at the final stage of the assembly process of the intermediate transfer belt device 15 at the manufacturing factory, the adjustment member 67 is operated by the operator so that the default position of the correction roller 13 becomes the center position of the movement range. In the market, when the default position of the correction roller 13 deviates greatly from the center position of the movement range due to subsequent distortion of the frame, the service member operates the adjustment member 67.
As a result, the meandering of the intermediate transfer belt 8 cannot be corrected within a predetermined time and it is determined that an abnormality has occurred in the control, and the operation of the apparatus 15 is stopped, or the movement range of the correction roller 13 is in the forward and reverse directions. Therefore, the occurrence of a problem that the meandering of the intermediate transfer belt 8 cannot be sufficiently corrected is suppressed.
The adjusting means for adjusting the position of the fixed end side shaft portion 13a of the correction roller 13 is not limited to the one in the present embodiment, and various forms can be used.

FIG. 12 is a perspective view showing another form of adjusting means, and is a perspective view of the vicinity of the correction roller 13 as seen from the front side.
The adjusting means shown in FIG. 12 has a point that the support shaft 67b (rotation center) of the adjusting member 67 is disposed close to the correction roller 13 (shaft portion 13a) and a screw 68 for fixing the adjusting member 67 to the frame 70. The presser plate 69 for preventing the bearing of the correction roller 13 (shaft portion 13a) from falling off is disposed on the adjustment member 67. Except for the point and the like, the configuration is almost the same as the adjusting means shown in FIG. The adjustment means shown in FIG. 12 has the adjustment scale 67c indicating the position (adjustment amount) of the adjustment member 67 in the rotation direction with respect to the frame 70, so that the adjustment work of the correction roller 13 described above is performed. Can be performed efficiently.

Hereinafter, the configuration and operation of the pressing member 88 that are characteristic of the intermediate transfer belt device 15 according to the present embodiment will be described in detail.
Referring to FIG. 5 and the like, the intermediate transfer belt device 15 in the present embodiment is a position corresponding to an end in the width direction of the intermediate transfer belt 8 (belt member), and a detection unit 80 (particularly, a detection unit). , A pressing member 88 (pressing member) that holds (regulates) warping or bending of the intermediate transfer belt 8 is provided at a position near the contact portion 82a) and in a non-image area. That is, the holding member 88 is installed on the side of the detection unit 80 and on the width direction end of the non-image area (outside of the width direction area where an image may be formed).
Specifically, the pressing member 88 sandwiches the front and back surfaces of the intermediate transfer belt 8 and comes into contact with the intermediate transfer belt 8 (or within a range where the effects of the present invention described later are exhibited). To be opposed to each other with a small distance. That is, the pressing member 88 is opposed to the first pressing member facing the outer peripheral surface at the widthwise rear end of the intermediate transfer belt 8 and the inner peripheral surface of the intermediate transfer belt 8 at the widthwise rear end. And a second pressing member.

With such a configuration, even if the intermediate transfer belt 8 is warped or bent, at least at the position of the abutting portion 82a of the detection unit 80, the warp or the deflection of the intermediate transfer belt 8 is corrected by the pressing member 88. Therefore, it is possible to reduce a decrease in detection accuracy of the detection unit 80 with respect to the belt shift of the intermediate transfer belt 8.
Specifically, as shown in FIG. 13 (B1), when the holding member 88 is not installed, if the intermediate transfer belt 8 is warped (a portion surrounded by a broken line in the figure), The contact portion 82a of the detection unit 80 may not contact the end portion of the intermediate transfer belt 8, and erroneous detection of the detection unit 80 may occur. On the other hand, as shown in FIG. 13A1, since the warp of the intermediate transfer belt 8 is corrected by installing the holding member 88 as in the present embodiment, the contact of the detection unit 80 The portion 82a reliably contacts the end of the intermediate transfer belt 8 to prevent erroneous detection of the detection portion 80, and the meandering correction of the intermediate transfer belt 8 is performed with high accuracy.
Similarly, as shown in FIG. 13 (B2), when the holding member 88 is not installed, it is detected that the intermediate transfer belt 8 is bent (a portion surrounded by a broken line in the drawing). In some cases, the detection portion 80 may be erroneously detected because the contact portion 82a of the portion 80 does not contact the end portion of the intermediate transfer belt 8. On the other hand, as shown in FIG. 13 (A2), since the bending of the intermediate transfer belt 8 is corrected by installing the holding member 88 as in the present embodiment, the contact of the detection unit 80 The portion 82a reliably contacts the end of the intermediate transfer belt 8 to prevent erroneous detection of the detection portion 80, and the meandering correction of the intermediate transfer belt 8 is performed with high accuracy.

In particular, the holding member 88 in the present embodiment is installed directly beside (close to) the abutting portion 82a of the detection unit 80, and thus efficiently regulates the warp and deflection of the intermediate transfer belt 8 and detects the detection unit. 80 erroneous detections can be prevented.
In the present embodiment, the holding member 88 is configured to face the front and back surfaces of the intermediate transfer belt 8, but the intermediate transfer belt 8 is warped or bent at the outer peripheral surface side or the inner peripheral surface. In the case of being limited to the surface side, the pressing member 88 can be configured to face only the outer peripheral surface or the inner peripheral surface of the intermediate transfer belt 8 corresponding to the position.
In this embodiment, the pressing member 88 (in particular, the first pressing member facing the outer peripheral surface of the intermediate transfer belt 8) does not interfere with the toner image carried on the intermediate transfer belt 8. Thus, it is installed in the non-image area (or non-paper passing area). It is to be noted that the holding member 88 is on the downstream side (the downstream side in the running direction of the intermediate transfer belt 8) with respect to the secondary transfer counter roller 12B (secondary transfer nip), and the photosensitive drums 1Y, 1M, In the case where it is installed on the upstream side with respect to the area facing 1C and 1K, such a restriction is eliminated.

Here, in the present embodiment, referring to FIGS. 5 and 7, the holding member 88 and the detection unit 80 are separately positioned and installed in the casing 90 of the intermediate transfer belt device 15. . In particular, as shown in FIG. 7, the detection unit 80 is fastened and fixed to the housing 90 (side plate) by screws 99.
On the other hand, as shown in FIG. 14, the detection unit 80 (detection means) can be installed so as to be directly positioned on the holding member 88. In that case, there is little influence of component accuracy and assembly accuracy, and the positional relationship between the pressing member 88 and the detection unit 80 (contact portion 82a) is directly determined. The portion 80 (abutting portion 82a) is easily installed at an ideal design position, and the above-described effects of the present embodiment are reliably exhibited.

Specifically, in FIG. 14A, the detection unit 80 is opposed to a pressing member 88 (formed to face the inner peripheral surface of the intermediate transfer belt 8) fixed to the housing 90. Are fastened and fixed by screws 99.
14B detects the pressing member 88 fixed to the housing 90 (formed so as to face the inner peripheral surface and the outer peripheral surface of the intermediate transfer belt 8). The part 80 is fastened and fixed by a screw 99.
In FIG. 14C, the detection unit 80 is opposed to a holding member 88 (formed so as to face the inner peripheral surface of the intermediate transfer belt 8) fixed to the housing 90. Fastened and fixed by screws 99. Further, a holding member 88a formed so as to face the outer peripheral surface of the intermediate transfer belt 8 is further fixed to the holding member 88 in that state by a screw (not shown) or the like. In such a configuration, after the intermediate transfer belt 8 is installed in the casing 90 in which the holding member 88 is installed, the holding member 88a facing the outer peripheral surface of the belt can be installed. 8 can be improved.

In the present embodiment, at least the abutment surface (or the opposed surface) that abuts against the intermediate transfer belt 8 is formed of a low-friction material. Specifically, the holding member 88 is formed of a resin material or a metal material having a certain degree of rigidity, and a thin film-like PET (polyester terephthalate) is attached to the contact surface (or the opposite surface). Has been.
As a result, even if the pressing member 88 is slidably contacted with the intermediate transfer belt 8, it is possible to reduce the wear on the surface and to reduce the increase in driving torque of the intermediate transfer belt 8. In particular, when an elastic layer or the like made of a rubber material is formed on the outer peripheral surface or the inner peripheral surface of the intermediate transfer belt 8, the surface friction resistance of the intermediate transfer belt 8 is increased. It is useful to form the surface with a low friction material such as PET.

In the present embodiment, the pressing member 88 and the contact part 82a of the detection unit 80 are configured as separate parts. However, the pressing member and the contact part of the detection means may be integrated. it can.
Specifically, as shown in FIG. 15, as a contact portion 82 a in the detection unit 80, a portion 82 a 1 (a portion functioning as a contact portion of the detection unit) that contacts the end of the intermediate transfer belt 8, and the intermediate transfer belt It is also possible to integrally form a portion 82a2 (a portion functioning as a pressing member) that contacts the front and back surfaces of 8 as one component.
As a result, the positional relationship between the part 82a2 functioning as a holding member and the part 82a1 functioning as the contact part of the detection unit is directly determined without any influence of component accuracy or assembly accuracy. The effect in the present embodiment described above is surely exhibited.

In this embodiment, as shown in FIG. 16, the correction roller 13 (one roller member), the holding member 88, and the detection unit 80 (detection means) are assembled in the intermediate transfer belt device 15 by a small assembly (sub -It can also be integrally formed as an assembled subunit 75. Specifically, the correction roller 13, the holding member 88, and the detection unit 80 are installed on the bracket 76 in the subunit 75.
In that case, meandering correction of the intermediate transfer belt 8 by changing the inclination of the rotation axis of the correction roller 13 by moving the subunit 75 based on the detection result of the detection unit 80 by the correction means 31 to 39 described above. Will be performed.
Even in such a case, there is little influence of component accuracy and assembly accuracy, and the positional relationship between the holding member 88 and the detection unit 80 (contact portion 82a) is determined with high accuracy. The detection unit 80 (contact portion 82a) is easily installed at an ideal design position, and the above-described effects of the present embodiment are surely exhibited.

In addition, the subunit 75 (correction roller 13) in which a plurality of members including the correction roller 13 are assembled (sub-assembled) in this way is not variable in inclination by correction means using a wire mechanism, The inclination can be varied by correction means using a cam mechanism.
Specifically, the subunit 75 shown in FIGS. 17 and 18 has a detection unit 80 fixed on the bracket 76 on the other end side in the same manner as in FIG. The subunit 75 swings in the X1 and X2 directions (up and down directions) around the support shaft 76a on the other end side by the rotation of the cam 96 engaged with the bottom portion on the one end side of the bracket 76. It is configured to move. The subunit 75 shown in FIGS. 17 and 18 is different from that shown in FIG. 11 in that the holding member 88 is not formed as a subunit.
On the other hand, the subunit 75 shown in FIGS. 19 and 20 has a detection unit 80 and a holding member 88 fixed on the bracket 76 on the other end side in the same manner as in FIG. Further, the subunit 75 is rotated in the X1 and X2 directions (vertical direction) around the support shaft 76a on the other end side by the rotation of a cam (not shown) engaged with the bottom portion on one end side of the bracket 76. It is configured to swing.

In this embodiment, at least the intermediate transfer belt 8 and the plurality of roller members 11, 12 </ b> A to 12 </ b> C, 13, 14 are detachable from the intermediate transfer belt device 15 (or the apparatus main body 100) as subunits. It can also be formed. Specifically, as shown in FIG. 21, the above-described subunit is a direction indicated by a white arrow (a direction along the width direction from the far side in the width direction toward the near side in the width direction) by the user or the service person. )) And is taken out from the intermediate transfer belt device 15 (or the device main body 100). Further, the subunit is moved in the direction opposite to the white arrow direction, and is attached to the intermediate transfer belt device 15 (or the device main body 100).
When configured in this manner, the holding member 88 (and the detection unit 80) is installed at a position in the intermediate transfer belt device 15 (or the device main body 100) that does not hinder the attachment / detachment operation of the subunit. Since it is not necessary to use the holding member 88 (or the detection unit 80) as a component of the subunit, the cost of the subunit can be reduced. Specifically, referring to FIG. 21, when viewed in a cross section perpendicular to the attaching / detaching direction of the subunit, the holding member 88 is located at a position facing the front and back surfaces of the intermediate transfer belt 8, and the frame of the subunit. It is installed at a position where it does not interfere with 71.

  As described above, in the intermediate transfer belt device 15 according to the present exemplary embodiment, at a position corresponding to the end in the width direction of the intermediate transfer belt 8 (belt member) and in the vicinity of the detection unit 80 (detection means). In the non-image area, since the holding member 88 that holds the warp and the bending of the intermediate transfer belt 8 is installed, the intermediate transfer belt 8 is warped and bent, and the width of the intermediate transfer belt 8 is detected by the detection unit 80. The problem that the position of the direction end cannot be detected accurately is reduced, and the meandering correction of the intermediate transfer belt 8 can be performed reliably.

  In the present embodiment, the present invention is applied to a belt device (intermediate transfer belt device 15) using the intermediate transfer belt 8 as a belt member. On the other hand, the present invention is also applied to a belt device using a transfer conveyance belt as a belt member (a belt device that transfers a plurality of color toner images onto a recording medium while conveying the recording medium on the belt member). The invention can be applied. Furthermore, the present invention is also applied to a belt device using a photosensitive belt (which functions as the photosensitive drum in the present embodiment and is an endless belt-shaped photosensitive member) as a belt member. can do. Also in these cases, the same effect as that of the present embodiment can be obtained by installing a pressing member that restricts the warping or bending of the belt member in the vicinity of the detecting means.

In the present embodiment, the present invention is applied to the intermediate transfer belt device 15 in which the adjustment member 67 (adjustment means) for adjusting the position of the fixed end side shaft portion 13a of the correction roller 13 is installed. Naturally, the present invention can also be applied to the intermediate transfer belt device 15 in which the member 67 (adjusting means) is not installed.
Further, in the present embodiment, as the detection means for detecting the position of the end portion of the belt member, the detection portion 80 provided with the contact portion 82a that contacts the belt end portion is used. However, the form of the detection means for detecting the position of the end of the belt member is not limited to this, and for example, an optical sensor disclosed in Patent Document 2 (a member that contacts the belt end is installed as the detection means). It is also possible to use non-contact detection means.
Further, in the present embodiment, the pressing member 88 is configured to abut against the belt member 8 so as to sandwich the front and back surfaces of the belt member 8 and to prevent warping or bending of the belt member 8. On the other hand, the pressing member 88 is brought into contact with only the front surface (front surface) or the back surface of the belt member 8 so as to prevent warping or bending of only the front surface (front surface) or the back surface of the belt member 8. It can also be configured.
Even in those cases, the same effects as in the present embodiment can be obtained.

  Further, the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1Y, 1M, 1C, 1K photosensitive drum (image carrier),
8 Intermediate transfer belt (belt member),
12A-12C roller member,
13 Correction roller (roller member),
13a, 13b shank,
15 Intermediate transfer belt device (belt device),
31 swing arm,
70, 71 frames,
75 subunits, 76 brackets,
80 detector (detector),
81 optical sensor,
82a contact part,
88 Holding member (holding member),
100 Image forming apparatus main body (apparatus main body).

JP 2006-343629 A JP 2011-118326 A JP 2000-34031 A

Claims (8)

A belt member that is stretched around a plurality of roller members, travels in a predetermined traveling direction, and an image is transferred to the surface thereof;
A detecting means which is installed at a position corresponding to the width direction end portion of the belt member and urges the belt member to detect the position of the width direction end portion of the belt member;
Correction means for changing the meandering of the belt member by varying the inclination of the rotation shaft of one of the plurality of roller members based on the detection result of the detection means;
A pressing member that is located in a non-image area at a position corresponding to the widthwise end of the belt member and in the vicinity of the detection means, and that holds the warp or / and bending of the belt member;
A belt device comprising:   The belt device according to claim 1, wherein the pressing member is in contact with the belt member so as to sandwich the front and back surfaces of the belt member.   The belt device according to claim 1, wherein the detection unit is installed so as to be positioned on the holding member. The detection means includes a contact portion that contacts the belt member,
The belt device according to any one of claims 1 to 3, wherein the pressing member and the contact portion of the detection means are integrated.   5. The belt device according to claim 1, wherein a contact surface of the pressing member that contacts the belt member is formed of a low friction material. The one roller member, the pressing member, and the detection means are integrally formed as a subunit,
The correction means corrects meandering of the belt member by moving the subunit based on a detection result of the detection means to vary an inclination of a rotation shaft of the one roller member. The belt apparatus in any one of Claims 1-5. At least the belt member and the plurality of roller members are detachably formed as a subunit with respect to the apparatus or the image forming apparatus main body,
The belt device according to any one of claims 1 to 5, wherein the pressing member is installed at a position that does not hinder the attachment / detachment operation of the subunit.   An image forming apparatus comprising the belt device according to claim 1.

Images