JP2009014956A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus constituted so that toner images formed on the surface of an image holding member of an endless belt form, which moves holding the toner images thereon, are read by a reading sensor, wherein the toner images on the surface of the image holding member are accurately read by the reading sensor and the image holding member is prevented from being scratched. <P>SOLUTION: The image forming apparatus includes: the image holding member 21 of the endless belt form, which moves holding toner images thereon; toner image forming means 10A to 10D, which form toner images on the surface of the image holding member; the reading sensor 9, which reads the toner images formed on the surface of the image holding member by the toner image forming means, wherein a backup member 24 which is abutted on the back of the image holding member, which is disposed opposite the reading sensor, so as to press the image holding member toward the reading sensor is arranged, and The face 24a of the backup member, which is abutted on the image holding member, is made of a low-friction soft material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a composite machine of these, and in particular, an endless belt-like image holding member that holds and moves a toner image, and a toner on the surface of the image holding member An image forming apparatus comprising: a toner image forming unit that forms an image; and a reading sensor that reads a toner image formed on the surface of the image holding member by the toner image forming unit. The toner image formed on the surface of the toner image can be accurately read, and the image holding member is prevented from being damaged.

  2. Description of the Related Art Conventionally, in image forming apparatuses such as copying machines, printers, facsimiles, and multi-function machines, image holding members that hold and move a toner image, such as a photoconductor on which a toner image is formed, or a photoconductor In the intermediate transfer body to which the toner image is transferred, a toner image having a predetermined pattern is formed on the surface of the image holding member in order to control the toner image to be appropriately formed on the image holding member. Reading is performed by a reading sensor.

  In particular, in recent years, when a full-color image is formed by forming a plurality of color toner images on the image holding member as described above, the timing of image formation is controlled so that the toner images of the respective colors are accurately overlapped. The toner image of each color formed on the surface of the image holding member is read by a reading sensor.

  In addition, as an image forming apparatus that performs such full-color image formation, toner images of different colors are formed on a plurality of photoconductors, and the toner images of the respective colors formed on the photoconductors are intermediated in an endless belt shape. Primary transfer is performed on the surface of the transfer belt, a full-color toner image is formed on the surface of the intermediate transfer belt, and the full-color toner image thus formed is secondarily transferred from the intermediate transfer belt to the recording medium. Things are widely used.

  Here, in such a full-color image forming apparatus, when the toner image of each color formed on the surface of the intermediate transfer belt is read by the reading sensor, the toner image formed on the surface of the reading sensor and the intermediate transfer belt. If the distance, angle, etc. vary, the toner image cannot be read accurately, and proper image control cannot be performed.

  For this reason, conventionally, as disclosed in Patent Document 1, a back contact member that contacts the back side of the intermediate transfer belt is provided at a position facing the read sensor, and the back contact member is provided between the read sensor and the intermediate portion. There has been proposed one that suppresses fluctuations in distance, angle, and the like with a toner image formed on the surface of a transfer belt.

  Here, in Patent Document 1, as described above, a plate-like member having a smooth surface on the back surface side of the intermediate transfer belt is provided as the back surface contact member that contacts the back surface side of the intermediate transfer belt. There have been proposed such a configuration and a configuration in which a pair of rotatable rollers are provided at a required interval.

  However, when the plate-like back contact member as described above is used, the intermediate transfer belt is not properly brought into contact with the entire surface of the back contact member, and the intermediate transfer belt is waved at a position facing the reading sensor. The distance between the reading sensor and the toner image formed on the surface of the intermediate transfer belt, the angle, etc. may fluctuate, and the intermediate transfer belt may be damaged by contact with the plate-like back contact member. It was.

  In addition, when a pair of rotatable rollers is provided as a back contact member at a required interval, the surface of the reading sensor and the intermediate transfer belt may be changed depending on the rotation center of each roller or a shift in the mounting position. There has been a problem that the distance and angle with the formed toner image fluctuate.

  Conventionally, as disclosed in Patent Document 2, an elastic member is provided so as to contact the back side of the intermediate transfer belt at a position facing the reading sensor, and the elastic member causes the reading sensor and the intermediate transfer belt to be in contact with each other. There has been proposed one that suppresses fluctuations in distance, angle, and the like with a toner image formed on the surface.

  Here, in Patent Document 2, it is proposed to use sponge, rubber, plastic or the like as an elastic member provided so as to contact the back side of the intermediate transfer belt as described above.

However, when an elastic member made of sponge or the like is brought into contact with the back side of the intermediate transfer belt, the elastic member is deformed when the intermediate transfer belt is driven, and a toner image formed on the surface of the reading sensor and the intermediate transfer belt. The distance, the angle, and the like of the belt may fluctuate, and the friction between the elastic member and the intermediate transfer belt may cause uneven driving of the intermediate transfer belt.
Japanese Patent Laid-Open No. 11-220586 JP 2000-275977 A

  The present invention uses an endless belt-like image holding member that holds and moves a toner image like the above intermediate transfer belt, and reads a toner image formed on the surface of the image holding member by a reading sensor. An object of the present invention is to solve the above problems in an image forming apparatus.

  That is, according to the present invention, in the image forming apparatus as described above, the toner image formed on the surface of the image holding member can be accurately read by the reading sensor, and the image holding member is The problem is to prevent damage.

  In the image forming apparatus according to the present invention, in order to solve the above-described problems, an endless belt-shaped image holding member that holds and moves a toner image, and a toner that forms a toner image on the surface of the image holding member In an image forming apparatus including an image forming unit and a reading sensor that reads a toner image formed on the surface of the image holding member by the toner image forming unit, the back side of the image holding member facing the reading sensor Further, a backup member that abuts the image holding member so as to urge the image holding member toward the reading sensor is provided, and a surface of the backup member that abuts the image holding member is made of a soft material with low friction.

  Here, as said low friction soft material used for the surface which a backup member contact | abuts with an image holding member, the raised fiber material etc. can be used, for example.

  In the image forming apparatus according to the present invention, in order to hold the endless belt-shaped image holding member in a balanced manner, it is preferable to provide the backup member on both sides in the width direction of the endless belt-shaped image holding member.

  In the image forming apparatus according to the present invention, a plurality of toner image forming units for forming toner images of different colors are provided on the surface of the image holding member, and a full color toner image is formed on the surface of the image holding member. Can be.

  As the endless belt-like image holding member that holds and moves the toner image, for example, a belt photoreceptor or an intermediate transfer belt in the form of an endless belt is used.

  When the endless belt-shaped image holding member is an intermediate transfer belt, the toner image forming unit is provided with a photoreceptor on which a toner image is formed, and the toner image formed on the photoreceptor is imaged. The image is transferred to an intermediate transfer belt that is a holding member.

  When the endless belt-shaped image holding member is an intermediate transfer belt, the image holding member abuts against the back side of the image holding member facing the reading sensor so as to urge the image holding member toward the reading sensor. When the backup member is provided, a rotation roller provided on the inner peripheral side of the intermediate transfer belt for rotationally driving the intermediate transfer belt, and a primary for primary transfer of the toner image formed on the photoreceptor to the intermediate transfer belt. The transfer member is attached to a pair of frames provided on a pair of frames provided on both sides in the width direction of the intermediate transfer belt, and the backup member is attached to an attachment member provided between the pair of frames. can do.

  In the image forming apparatus of the present invention, the toner image is formed on the surface of the endless belt-shaped image holding member that holds and moves the toner image by the toner image forming means, and thus formed on the surface of the image holding member. When the toner image is read by the reading sensor, a backup member is provided on the back side of the image holding member facing the reading sensor, and the image holding member is urged toward the reading sensor by the backup member. The image holding member does not wave at the opposite position, and is flat along the backup member, and the distance and angle between the image holding member and the reading sensor are maintained constant. .

  In the image forming apparatus of the present invention, since the surface of the backup member that contacts the image holding member is made of a soft material with low friction, the image holding member is damaged by the contact with the backup member. In addition, the image holding member does not move unevenly due to friction caused by contact with the backup member, and the image holding member is stably moved while being in contact with the backup member.

  As a result, in the image forming apparatus of the present invention, the image holding member is not damaged, and the toner image formed on the surface of the image holding member can be accurately read by the reading sensor. Thus, stable image control can be performed.

  Next, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In this embodiment, an image forming apparatus using an intermediate transfer belt as an endless belt-shaped image holding member that holds and moves a toner image will be described.

  Here, in the image forming apparatus of this embodiment, as shown in FIG. 1, four imaging cartridges 10A to 10D are mounted in the apparatus main body 1 as toner image forming means.

  Here, in each of the imaging cartridges 10 </ b> A to 10 </ b> D, the rotating drum-shaped photoconductor 11, the charging device 12 that charges the surface of the photoconductor 11, and the image information on the surface of the charged photoconductor 11 are displayed. An exposure apparatus 13 that forms an electrostatic latent image on the surface of the photoconductor 11 by performing appropriate exposure, and supplies toner to the electrostatic latent image formed on the surface of the photoconductor 11 to form a toner image. After the toner image formed on the surface of the photosensitive member 11 and the developing device 14 is transferred to the intermediate transfer belt 21, the cleaning blade 15a is pressed against the surface of the photosensitive member 11 and remains on the surface of the photosensitive member 11. A first cleaning device 15 is provided to remove residues such as toner.

  In the image forming apparatus according to this embodiment, when full color image formation is performed, each developing device 14 in each of the imaging cartridges 10A to 10D has different colors of black, yellow, magenta, and cyan. Toner is accommodated, and a toner image of each color is formed on the surface of each photoconductor 11 in each of the imaging cartridges 10A to 10D.

  Next, the toner image of each color formed on the surface of each photoconductor 11 in each imaging cartridge 10 </ b> A to 10 </ b> D in this way is placed on the surface of the intermediate transfer belt 21 that is stretched around the rotation roller 22 and rotates. The toner image is sequentially transferred by each roller-shaped primary transfer member 23 provided so as to face the body 11 with the intermediate transfer belt 21 therebetween, and a full-color toner image is formed on the surface of the intermediate transfer belt 21. I am doing so.

  The full color toner image thus formed on the surface of the intermediate transfer belt 21 is guided to the position of the secondary transfer member 5 in the form of a roller, while the recording medium S is fed by the paper feed roller 3. The recording medium S is guided by the timing roller 4 between the intermediate transfer belt 21 on which the full-color toner image is formed and the secondary transfer member 5 at an appropriate timing, and is formed on the surface of the intermediate transfer belt 21. The full color toner image is transferred to the recording medium S.

  Next, the recording medium S to which the full-color toner image has been transferred in this way is guided to the fixing device 6, and after fixing the full-color toner image on the recording medium S, the recording medium S is discharged by the paper discharge roller 7. I try to make it paper.

  Further, after the full-color toner image formed on the surface of the intermediate transfer belt 21 as described above is transferred to the recording medium S, the cleaning blade 8 a provided in the second cleaning device 8 is provided on the surface of the intermediate transfer belt 21. The toner is removed from the intermediate transfer belt 21 without being transferred onto the recording medium S and remaining on the surface of the intermediate transfer belt 21.

  Here, in the image forming apparatus of this embodiment, since the toner images of the respective colors formed on the surface of the intermediate transfer belt 21 are accurately overlapped, the timing of image formation is controlled. When a toner image having a predetermined pattern is formed on the surface of the intermediate transfer belt 21 by 10A to 10D and this toner image is read by the reading sensor 9, as shown in FIG. A reading sensor 9 is provided between the primary transfer member 23 positioned and the rotating roller 22 facing the secondary transfer member 5 at a position spaced from the surface of the intermediate transfer belt 21 and the reading sensor 9. The intermediate transfer belt 21 is urged toward the reading sensor 9 on the back surface side of the intermediate transfer belt 21 that is opposed to A backup member 24 abuts provided, the back-up member 24 is a surface contacting with the intermediate transfer belt 21 so as to constitute a low-friction resistant soft material.

  Here, when the backup member 24 that contacts the intermediate transfer belt 21 so as to bias the intermediate transfer belt 21 toward the reading sensor 9 is provided on the back surface side of the intermediate transfer belt 21 facing the reading sensor 9 in this manner, As shown in FIG. 2, the intermediate transfer unit 20 in which the rotating roller 22 and the primary transfer member 23 are attached to a pair of frames 25 provided on both sides in the width direction of the intermediate transfer belt 21 is used. ing.

  As shown in FIGS. 2 and 3, between the primary transfer member 23 located on the most downstream side in the moving direction of the intermediate transfer belt 21 and the rotating roller 22 facing the secondary transfer member 5. A mounting member 26 is provided so as to span between the pair of frames 25.

  Further, the backup member 24 protrudes toward the reading sensor 9 from the attachment member 26 at the positions on both sides in the width direction of the intermediate transfer belt 21 with respect to the attachment member 26, and the intermediate transfer belt 21 moves. The auxiliary member 27 protrudes further to the side of the reading sensor 9 than the mounting member 26 in the middle of the pair of backup members 24, and protrudes toward the reading sensor 9 in the middle of the pair of backup members 24. The transfer belt 21 is attached so as to protrude downstream in the moving direction. The amount by which the auxiliary member 27 protrudes to the reading sensor 9 side and the amount by which the intermediate transfer belt 21 protrudes downstream in the moving direction is made slightly smaller than that of the backup member 24, so that the intermediate transfer belt 21 is in contact with the backup member 24 in a stretched state.

  Further, when the backup member 24 is attached to the attachment member 26 as described above, a soft material having low friction such as a raised fiber material on the surface where the backup member 24 comes into contact with the intermediate transfer belt 21, such as Chiyoda Integre Co., Ltd. A surface member 24a made of a manufactured CIC (trade name) is used, and the surface member 24a is attached to the attachment member 26 via a rigid support member 24b such as plastic. The material of the auxiliary member 27 is not particularly limited. However, when the intermediate transfer belt 21 comes into contact, the intermediate transfer belt 21 is damaged or friction with the intermediate transfer belt 21 is increased. In order to prevent this, although not shown in the figure, it is preferable to configure in the same manner as the backup member 24 described above.

  When the backup member 24 is provided as described above and the intermediate transfer belt 21 is brought into contact with the reading sensor 9 so as to be biased, the intermediate transfer belt 21 undulates at a position facing the reading sensor 9. In this case, the flat state along the backup member 24 is maintained, and the distance and angle between the intermediate transfer belt 21 and the reading sensor 9 are maintained constant.

  Further, when the surface member 24 a made of a low frictional soft material such as a raised fiber material is used on the surface where the backup member 24 comes into contact with the intermediate transfer belt 21 as described above, the contact with the backup member 24 causes an intermediate state. There is no possibility that the transfer belt 21 is damaged or the driving unevenness is generated in the intermediate transfer belt 21 due to friction caused by contact with the backup member 24, and the intermediate transfer belt 21 is stably in contact with the backup member 24. The toner image having a predetermined pattern that has been moved and formed on the surface of the intermediate transfer belt 21 can be appropriately read by the reading sensor 9.

  In the image forming apparatus of this embodiment, as described above, the auxiliary member 27 protrudes further toward the reading sensor 9 than the mounting member 26 in the middle of the pair of backup members 24 and the intermediate transfer belt 21 moves in the downstream direction. Since the intermediate transfer belt 21 undulates between the pair of backup members 24, the intermediate transfer belt 21 comes into contact with the auxiliary member 27 and waves. The hit state is eased, and the intermediate transfer belt 21 is prevented from colliding with the mounting member 26 and being damaged.

  In the image forming apparatus of this embodiment, reading is performed between the primary transfer member 23 located on the most downstream side in the moving direction of the intermediate transfer belt 21 and the rotary roller 22 facing the secondary transfer member 5. While the sensor 9 is provided at a required distance from the surface of the intermediate transfer belt 21 and the backup member 24 is provided on the back side of the intermediate transfer belt 21 facing the reading sensor 9, the reading sensor 9 and the backup member 24 are provided. There is no particular limitation on the position where the is provided.

  For example, as shown in FIG. 5, a reading sensor 9 and a backup member 24 provided on the back surface side of the intermediate transfer belt 21 that faces the reading sensor 9 are located in the middle of the rotating roller 22 that faces the secondary transfer member 5. Provided on the downstream side of the transfer belt 21 in the moving direction, the toner image is formed on the surface of the intermediate transfer belt 21 as described above, and the toner image passes through the secondary transfer member 5 separated from the intermediate transfer belt 21 to be read sensor. 9, the toner image formed on the surface of the intermediate transfer belt 21 is read by the reading sensor 9 in a state where the intermediate transfer belt 21 is biased toward the reading sensor 9 by the backup member 24. It is also possible to do so.

1 is a schematic explanatory view of an image forming apparatus using an intermediate transfer belt as an endless belt-shaped image holding member that holds and moves a toner image, showing an image forming apparatus according to an embodiment of the present invention. 5 is a schematic bottom view showing a state in which a pair of backup members and auxiliary members are attached by attachment members between a pair of frames in an intermediate transfer unit provided with an intermediate transfer belt in the image forming apparatus of the embodiment. FIG. FIG. 5 is a partial explanatory view showing a state in which a pair of backup members and auxiliary members are attached to attachment members provided between a pair of frames in the intermediate transfer unit in the image forming apparatus of the embodiment. 4 is a partial explanatory view showing a state in which a toner image formed on an intermediate transfer belt is read by a reading sensor at a position facing the backup member in the image forming apparatus of the embodiment. FIG. FIG. 10 is a partial explanatory diagram of a modified example in which the position where the reading sensor and the backup member are provided is changed in the image forming apparatus of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Paper feed roller 4 Timing roller 5 Secondary transfer member 6 Fixing device 7 Paper discharge roller 8 Second cleaning device 8a Cleaning blade 9 Reading sensor 10A-10D Imaging cartridge 11 Photoconductor 12 Charging device 13 Exposure device 14 Development device 15 First cleaning device 15a Cleaning blade 20 Intermediate transfer unit 21 Intermediate transfer belt (image holding member)
22 Rotating roller 23 Primary transfer member 24 Backup member 24a Surface member 24b Support member 25 Frame 26 Mounting member 27 Auxiliary member S Recording medium

Claims (6)

  An endless belt-shaped image holding member that holds and moves the toner image, a toner image forming unit that forms a toner image on the surface of the image holding member, and the toner image forming unit that forms the surface of the image holding member. In the image forming apparatus provided with the reading sensor for reading the toner image, the backup is in contact with the back side of the image holding member facing the reading sensor so as to urge the image holding member toward the reading sensor. An image forming apparatus, wherein a member is provided, and a surface of the backup member that contacts the image holding member is made of a soft material having low friction.   2. The image forming apparatus according to claim 1, wherein the low friction soft material is made of a raised fiber material.   3. The image forming apparatus according to claim 1, wherein the backup member is provided on both sides in the width direction of the endless belt-like image holding member.   4. The image forming apparatus according to claim 1, wherein a plurality of toner image forming means for forming toner images of different colors are provided on the surface of the image holding member. Image forming apparatus.   5. The image forming apparatus according to claim 1, wherein the toner image forming unit includes a photoreceptor on which a toner image is formed, and the image holding member is formed from the photoreceptor. An image forming apparatus comprising an intermediate transfer belt onto which a toner image is transferred.   6. The image forming apparatus according to claim 5, wherein a rotation roller provided on an inner peripheral side of the intermediate transfer belt and rotationally driving the intermediate transfer belt, and a toner image formed on the photoreceptor are used as the intermediate transfer belt. A primary transfer member for primary transfer uses an intermediate transfer unit attached to a pair of frames provided on both sides in the width direction of the intermediate transfer belt, and an attachment member provided to span between the pair of frames. An image forming apparatus having the backup member attached thereto.

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