JP2010277066A - Transfer device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer device of an image forming apparatus which firmly holds a primary transfer position where a developed image is transferred to a transfer belt from an image carrier with a user-friendly mechanism. <P>SOLUTION: The transfer device includes: an endless transfer belt 14 that is stretched across a pair of separate supporting members 41 and 42, so as to be rotated; transfer members 20K, 20Y, 20M and 20C provided to face the image carriers 16K, 16Y, 16M and 16C across the transfer belt 14, and coming into contact with the image carriers 16K, 16Y, 16M and 16C through the transfer belt 14, and transferring the developed images formed on the image carriers 16K, 16Y, 16M and 16C to the transfer belt 14; and a belt supporting member 45 arranged to face the image carrier 16K through the transfer belt 14, and increasing an area of the transfer belt 14 coming into contact with the image carrier 16K. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transfer device and an image forming apparatus including the transfer device.

  In an image forming apparatus using a tandem color system, image forming units for each color (Y: yellow, M: magenta, C: cyan, K: black) having a drum-shaped photoconductor are arranged in parallel, and the photoconductors are arranged on each photoconductor. The toner images of a plurality of colors formed are primarily transferred to an endless intermediate transfer belt, and then secondarily transferred to a recording medium such as paper to obtain a color image output. Normally, the tangent lines between the photoconductors of the respective colors and the intermediate transfer belt are arranged in a straight line, and the width of the area where the intermediate transfer belt contacts the photoconductors of the respective colors is constant.

  In such an image forming apparatus, the intermediate transfer belt is moved from the photoconductor to the secondary transfer position where the color image on the intermediate transfer belt is transferred to the conveyed recording medium, due to an impact generated when the recording medium enters or exits. The primary transfer position to which the toner image is transferred may be shifted. If the primary transfer position is shifted as described above, an image defect occurs.

  Patent Document 1 is cited as a method that firmly holds the primary transfer position.

  In Patent Document 1, a photosensitive drum that forms a black toner image closest to a secondary transfer position for transferring a toner image to a recording medium among four toner image forming portions that form a color image is used as a belt of an intermediate transfer belt. It has been shown that the adhesion between the photosensitive member and the intermediate transfer belt is improved by biting inside the loop.

  However, in the mechanism of Patent Document 1, the photoconductor that forms a black image is always in contact with the intermediate transfer belt. If the photoconductor and the intermediate transfer belt are always in contact with each other, the photoconductor deteriorates. Therefore, it is not preferable that the photoconductor and the intermediate transfer belt are always in contact. Further, with the configuration of Patent Document 1, it is only possible to improve the adhesion between the photoreceptor and the intermediate transfer belt.

  The present invention has been made to solve the above problems, and a transfer device that firmly holds the primary transfer position between the photosensitive member and the intermediate transfer belt during image formation with a mechanism that further enhances convenience. An object of the present invention is to provide an image forming apparatus including the same.

  In order to solve the above problems, a transfer device according to the present invention is opposed to an image carrier via an endless transfer belt that is rotatably provided across a pair of spaced apart support members. A transfer member for transferring the developed image formed on the image carrier to the transfer belt, and opposed to the image carrier via the transfer belt, and acting on the transfer belt. And a belt support member for increasing a region in contact with the image carrier.

  The image forming apparatus according to the present invention is rotatable around a supply unit that supplies a recording medium, an image forming unit that forms a document image as a developed image on an image carrier, and a pair of spaced apart support members. An endless transfer belt provided; a transfer member provided opposite to the image carrier with the transfer belt interposed therebetween; and a transfer member for transferring the developed image formed on the image carrier to the transfer belt; and the transfer belt The developed image transferred above, a secondary transfer member for transferring from the supply unit to the recording medium, and disposed to face the image carrier via the transfer belt, acting on the transfer belt, And a transfer device including a belt support member that increases a region of the transfer belt that contacts the image carrier.

  By using the transfer device and the image forming apparatus of the present invention, it is possible to firmly hold the primary transfer positions on the photosensitive member and the intermediate transfer belt during image formation with a mechanism that improves convenience.

Schematic configuration diagram of an image forming apparatus 1 is a schematic configuration diagram of a transfer device according to a first embodiment. Schematic configuration diagram of the transfer device in the state of the color printing mode in the second embodiment Schematic configuration diagram of a transfer device in a monochrome printing mode in the second embodiment Schematic configuration diagram of the transfer device in the all-separation mode in the second embodiment Schematic configuration diagram of the transfer device in the state of the color printing mode in the third embodiment Schematic configuration diagram of a transfer device in a monochrome printing mode in the third embodiment

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
A first embodiment will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing the internal structure of the image forming apparatus.

  The image forming apparatus 1 includes an image reading unit 4 that captures a document as image data, and an image forming unit 2 that outputs the image data as a visible image. The image forming unit 2 includes an image forming unit, a fixing device, and the like described later including an image carrier such as a drum-shaped photoconductor. The image forming apparatus 1 further includes a paper supply unit 3 that can supply an arbitrary size paper P used as an image recording medium to the image forming unit 2.

  The image reading unit 4 includes a transparent document placing table 8, a carriage 9, an exposure lamp 10, a reflecting mirror 11, an imaging lens 12 that converges reflected light, and a CCD (Charge Coupled) that converts image information from the reflected light into an analog signal. Device) 13 is provided.

  The yellow (Y), magenta (M), cyan (C), and black (K) image forming units have the same configuration and perform the same operation. Therefore, the black (K) image forming unit 15K is taken as an example. ,explain.

  The image forming unit 15K includes a drum-shaped photosensitive member 16K as an image carrier, a laser unit 17K that forms an electrostatic latent image on the photosensitive member 16K, a charging device 18K sequentially disposed around the photosensitive member 16K, and a developing unit. A device 19K, a cleaner 22K, and a static elimination lamp 23K are provided.

  The document to be copied is placed on the document table 8 or set on a known automatic document feeder 30 arranged on the table 8. When a copy button (not shown) is pressed, the carriage 9 and the exposure lamp 10 provided on the carriage 9 are provided on the document on the table 8 or the document sent to the exposure position of the table 8 by the document feeder 30. When light is applied from below the document table 8 by the exposure unit, the reflected light from the document is guided by the reflection mirror 11, converged by the imaging lens 12, and the reflected light image is projected onto the CCD 13. The light from the exposure lamp 10 scans the document surface in synchronization with the movement of the carriage 9 (from left to right in FIG. 1). This scanning light is taken into the CCD 13 as image information, outputted as an analog signal, and then converted into a digital signal. Thereafter, the digitized image information is subjected to image processing as necessary, and then transmitted to the laser unit 17K as image data. The image information converted into the digital signal may be temporarily stored in a recording device such as an HDD (Hard Disk Drive).

  When image formation is started in the image forming unit 2, the charging device 18K supplies electric charges to the outer peripheral surface of the rotating photoconductor 16K, and charges the outer surface of the photoconductor 16K to a uniform potential. Next, the laser unit 17K irradiates a laser beam modulated by the image data transmitted from the CCD 13 toward the outer surface of the photoreceptor 16K. This laser beam is scanned along the rotation axis of the drum-shaped photoconductor, and an electrostatic latent image corresponding to image data is formed and held on the outer peripheral surface of the rotating photoconductor 16K. Further, a developer such as toner is provided on the outer peripheral surface of the photoreceptor 16K by the developing device 19K, and the electrostatic latent image is converted into a toner image, that is, a developed image.

  The developing device 19K includes a developing roller 24K that is rotatably provided. When the developing roller 24K is disposed so as to face the photoconductor 16K and rotates, toner is supplied to the photoconductor 16K. When a toner image is formed on the outer peripheral surface of the photoreceptor 16K, the toner image is electrostatically transferred to the intermediate transfer belt 14 by the primary transfer roller 20K, which is a transfer member that contacts the photoreceptor 16K via the intermediate transfer belt 14. Is transferred to. The mechanism portion that performs the transfer in this way is particularly referred to as a transfer device. The transfer device will be described later. Further, the toner on the photoconductor 16K that has not been transferred is removed by the cleaner 22K located downstream of the primary transfer roller 20K in the rotation direction of the photoconductor 16K, and further, the residual toner on the outer peripheral surface of the photoconductor 16K. The electric charge is removed by the static elimination lamp 23K. In the case of forming a color image, the above operation is similarly performed in the image forming units 15Y, 15M, and 15C.

  The toner image transferred to the intermediate transfer belt 14 is electrostatically transferred onto the paper transported from the paper supply unit 3 through the transport path by the secondary transfer roller 25. Thereafter, the paper P on which the toner image is transferred is conveyed to the fixing device 26, and the toner image transferred onto the paper is fixed on the paper by the fixing device 26. The paper on which the toner image has been fixed and the image formation has been completed is discharged onto a paper tray 28 serving as a discharge unit by a transport roller 27.

  The above is the outline of the operation for forming an image on a sheet as a recording medium.

  Next, the transfer device 40 according to the present invention will be described. FIG. 2 is a schematic configuration diagram of the transfer device 40 according to the first embodiment of the present invention.

  The transfer device 40, for example, applies a tension to the drive roller 41, the driven roller 42, the endless intermediate transfer belt 14 spanning the drive roller 41 and the driven roller 42 as a support member, and the intermediate transfer belt 14. A plurality of tension rollers 43 and a primary transfer roller are provided so as to face the photoconductor through the intermediate transfer belt, and form a primary transfer position for transferring an image on the photoconductor to the intermediate transfer belt. The primary transfer rollers 20K, 20C, 20M, and 20Y are sequentially disposed along the intermediate transfer belt 14 corresponding to the photosensitive members 16K, 16C, 16M, and 16Y, and toner images formed on the corresponding photosensitive member surfaces. Is attached to the intermediate transfer belt 14 as described above.

  Further, the transfer device 40 includes a secondary transfer roller 44 that is a secondary transfer member that contacts the driving roller 41 via the intermediate transfer belt 14 and forms a secondary transfer position. The intermediate transfer belt 14 is moved endlessly in the same direction by the rotational force of the driving roller 41 that is driven to rotate counterclockwise in the figure by a driving means (not shown). As shown in the figure, the secondary transfer roller 44 is located upstream of the primary transfer roller 20K in the moving direction of the intermediate transfer belt 14.

  In such a transfer device 40, a belt support member is provided between the black (K) primary transfer roller 20K and the cyan (C) primary transfer roller 20C so as to be in contact with the intermediate transfer belt 14. An idle roller 45 is arranged. The idle roller 45 is disposed so that the belt loop of the intermediate transfer belt 14 spreads outward while in contact with the black (K) photoreceptor 16K via the intermediate transfer belt 14. By providing the idle roller 45 in this way, the amount of winding of the intermediate transfer belt 14 around the photosensitive member 16K increases. In other words, when the idle roller 45 acts on the intermediate transfer belt 14, the contact area of the intermediate transfer belt 14 with the photoconductor 16K can be increased.

  As described above, the idle roller 45 is provided between the black (K) photoconductor 16K and the cyan (C) photoconductor 16C so that the belt loop of the intermediate transfer belt 14 spreads outward. The winding amount of the intermediate transfer belt 14 is increased, and the adhesion between the intermediate transfer belt 14 and the photoconductor 16K is increased. For this reason, it is less susceptible to the impact on the intermediate transfer belt that occurs when the recording medium enters or exits the secondary transfer position, and further to the primary transfer position.

  In the above embodiment, the idle roller 45 is provided between the black (K) photoconductor 16K and the cyan (C) photoconductor 16C. However, the idle roller 45 is connected to the black (K) photoconductor 16K. You may provide between secondary transfer positions. Also in this case, the same effect as the above embodiment can be obtained.

  In the above-described embodiment, only the black (K) photoreceptor 16K that is closest to the secondary transfer position and is most susceptible to the impact at the secondary transfer position has a large amount of winding of the intermediate transfer belt 14. Although the idle roller is provided, the transfer belt is not limited to the black (K) photoconductor but also the yellow (Y), magenta (M), and cyan (C) photoconductors as in the K photoconductor. The idle roller 45 may be provided so that the winding amount of the 14 is increased.

  According to the above embodiment, the primary transfer position is firmly held by providing the idle roller so that the amount of the intermediate transfer belt wound around the photosensitive member is increased, and the recording medium enters and exits the secondary transfer position. It is possible to prevent image defects due to an impact generated when the image is generated.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.

  Hereinafter, the same reference numerals are used for the same parts as those of the first embodiment, and only the characteristic parts of the present embodiment will be described.

  In the image forming apparatus 1 of the present embodiment, a color printing mode for forming a color image on a recording medium, a monochrome printing mode for forming a monochrome image, and all the photosensitive members and the intermediate transfer belt during transportation. It has a switching mechanism for all separation modes for separation.

  In the color printing mode, the intermediate transfer belt 14 is brought into contact with the photosensitive members 16K, 16Y, 16M, and 16C of the respective colors, and the developer images of the respective colors are transferred from the photosensitive members to the intermediate transfer belt 14.

  In the monochrome printing mode, the intermediate transfer belt 14 is brought into contact only with the black (K) photosensitive member 16K, and the black (K) developer image is transferred from the photosensitive member to the intermediate transfer belt 14, and it is necessary to operate it. The other photoreceptors 16Y, 16M, and 16C of other colors are separated from the intermediate transfer belt 14 to reduce the friction between the yellow (Y), magenta (M), and cyan (C) photoreceptors and the intermediate transfer belt 14. Let

  FIG. 3 is a schematic configuration diagram when the transfer device is in the color printing mode.

  The transfer device 40 according to the present embodiment includes a switching unit 50 that switches between a color printing mode, a monochrome printing mode, and an all separation mode. The switching unit 50 (switching unit) includes a monochrome unit 52 including a black (K) primary transfer roller 20K, an idle roller 45, and a manual operation lever 51 attached to the eccentric cam 60, a yellow (Y), A color unit 53 including a magenta (M) and cyan (C) primary transfer roller, an eccentric cam 62 and a guide pin 64; The eccentric cam 62 is fitted in a recess at the top of the casing 55 of the color unit 53. A motor (not shown) is connected to the eccentric cam 62 of the color unit 53, and the eccentric cam 62 is rotated by this motor. Further, the guide pin 64 is fixed and fitted in a long hole 66 provided in the housing 55. The monochrome unit 52 and the color unit 53 are connected by a switching member 54.

  FIG. 4 is a schematic configuration diagram showing the transfer device in the monochrome printing mode. In the monochrome printing mode, the eccentric cam 62 of the color unit 53 is rotated by the motor. As the eccentric cam 62 rotates on the recess of the housing, the entire color unit 53 moves upward along the long hole 66 in which the guide pin 64 is fitted. In this manner, the yellow (Y), magenta (M), and cyan (C) photoreceptors and the intermediate transfer belt 14 are separated from each other.

  FIG. 5 is a schematic configuration diagram showing the transfer device in the all separation mode. To enter the full separation mode, the eccentric cam 60 of the monochrome unit 52 is rotated by further rotating the manual lever 51 90 degrees clockwise in the drawing in the monochrome printing mode. As the eccentric cam 60 rotates, the monochrome unit 52 moves upward. Thus, when the monochrome unit 52 moves upward, the black (K) photosensitive member 16K and the idle roller 45 are separated from the intermediate transfer belt.

  When this embodiment is used, when it is not necessary to bring the photosensitive member into contact with the intermediate transfer belt during transportation, the idle roller 45 is moved together with the photosensitive member, and the primary transfer position is firmly held only during printing. Is possible. Therefore, it is possible to prevent deterioration of the intermediate transfer belt 14 due to friction with the photosensitive member, compared to the case where the photosensitive member and the intermediate transfer belt are always brought into contact with each other.

  As in the first embodiment, in this embodiment, the idle roller 45 is provided only in the black (K) image forming unit. However, the idle roller 45 is also idle in yellow (Y), magenta (M), and cyan (C). A configuration may be adopted in which a roller is arranged so that the idle roller moves along with the movement of the color unit 53 and can be separated from the intermediate transfer belt.

  In this embodiment, the manual separation lever 51 is used to switch to the full separation mode, but the switching mechanism to each mode is not limited to this.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS.

  Hereinafter, the same reference numerals are used for the same parts as those in the first and second embodiments, and only the characteristic parts of the present embodiment will be described.

  The transfer apparatus according to the present embodiment also has a switching mechanism between a color print mode and a monochrome print mode, as in the second embodiment.

  FIG. 6 is a schematic configuration diagram of the transfer device in the state of the color printing mode in the present embodiment. The members of the transfer device and the method of moving the color unit are the same as in the second embodiment. In this embodiment, when the color print mode is taken, the idle roller 45 is not arranged so that the amount of winding of the intermediate transfer belt 14 around the black (K) photoconductor 16K is increased. The switching member 54 has a fulcrum 54a and rotates around the fulcrum 54a.

  FIG. 7 is a schematic configuration diagram of the transfer device in the monochrome printing mode in the present embodiment. When the color unit 53 moves upward so that the yellow (Y), magenta (M), and cyan (C) photoreceptors move away from the intermediate transfer belt 14, the switching member 54 rotates in the direction A shown in FIG. The monochrome unit 52 is pushed down by the switching member 54. Since the portion of the eccentric cam 60 of the monochrome unit 52 is fixed, the monochrome unit 52 is inclined. Then, the idle roller 45 moves so as to spread the belt loop of the intermediate transfer belt 14, and the amount of winding of the intermediate transfer belt 14 around the black (K) photoreceptor 16K increases.

  According to the present embodiment, the idle roller 45 can be arranged so that the amount of winding of the intermediate transfer belt 14 around the black (K) photoreceptor 16K increases only in the monochrome printing mode. In the color printing mode, the intermediate transfer belt 14 is sandwiched from four nip areas formed by four photosensitive members of yellow (Y), magenta (M), cyan (C), and black (K) and a transfer roller. ) And the monochrome printing mode having only one nip area by the photosensitive roller 16K and the transfer roller 20K, the recording medium is less affected when the recording medium enters and exits the secondary transfer position. Therefore, the winding amount of the intermediate transfer belt 14 around the photosensitive member 16K may be increased only in the monochrome printing mode. In such a case, it is effective to provide a mechanism for moving the idle roller 45 in conjunction with switching to the monochrome printing mode as in this embodiment.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming part 3 Paper supply part 4 Image reading part 8 Original placing table 9 Carriage 10 Exposure lamp 11 Reflecting mirror 12 Imaging lens 13 CCD
14 Transfer belts 15K, 15Y, 15M, 15C Image forming units 16K, 16Y, 16M, 16C Photoconductors 20K, 20Y, 20M, 20C Primary transfer roller 25 Secondary transfer roller 40 Transfer device 41 Drive roller 42 Driven roller 43 Tension roller 45 Idle roller 52 Monochrome unit 53 Color unit

JP 2007-199636 A

Claims (9)

An endless transfer belt that is rotatably provided across a pair of spaced support members;
A transfer member provided opposite to the image carrier via the transfer belt, and transferring the developed image formed on the image carrier to the transfer belt;
A belt support member disposed opposite to the image carrier via the transfer belt and acting on the transfer belt to increase the area in contact with the image carrier;
A transfer apparatus comprising:   The transfer device according to claim 1, wherein the belt support member is disposed so as to spread a belt loop of the transfer belt outward while in contact with the image carrier via the transfer belt.   The image forming apparatus further includes a secondary transfer member that contacts with one of the pair of support members via the transfer belt to form a secondary transfer position. The transfer device according to claim 1, wherein the transfer device transfers the ink to the transfer device.   4. The transfer apparatus according to claim 3, wherein a plurality of the image carriers are provided along the transfer belt, and the belt support member is provided for the image carrier closest to the secondary transfer position.   A switching unit that switches the image carrier and the transfer belt to a separated state, and the belt support member is moved away from the transfer belt as the image carrier and the transfer belt are separated by the switching unit. The transfer device according to claim 1, wherein the transfer device is separated. An endless transfer belt provided across a pair of spaced apart support members;
A color image carrier on which a color image is formed on the surface and a monochrome image carrier on which a monochrome image is formed on the surface are provided to face each other with the transfer belt interposed therebetween. A transfer member for transferring an image to be formed to the transfer belt;
A switching unit for switching between a color printing mode in which the color image carrier and the monochrome image carrier are in contact with the transfer belt and a monochrome printing mode in which only the monochrome image carrier is in contact;
It is arranged to face the monochrome image carrier pair via the transfer belt, and when it is switched to the monochrome print mode by the switching unit, it acts on the transfer belt to the monochrome image carrier of the transfer belt. A belt support member that increases the contact area;
A transfer apparatus comprising: A supply unit for supplying a recording medium;
An image forming unit that forms an original image on the image carrier as a developed image;
An endless transfer belt that is rotatably provided across a pair of spaced apart support members, and a developed image formed on the image carrier that is provided opposite the image carrier with the transfer belt interposed therebetween. A transfer member to be transferred to the transfer belt; a developed image transferred onto the transfer belt; a secondary transfer member to be transferred from the supply unit to the recording medium; and the image carrier through the transfer belt. And a belt support member that acts on the transfer belt and increases a region of the transfer belt that contacts the image carrier,
An image forming apparatus comprising:   A switching unit configured to switch the image carrier and the transfer belt to a separated state, and the belt support member is moved to the intermediate transfer unit as the image carrier and the intermediate transfer belt are separated by the switching unit. The image forming apparatus according to claim 7, wherein the image forming apparatus is separated from the belt. A supply unit for supplying a recording medium;
An image forming unit for forming a document image as a developed image on a color image carrier and a monochrome image carrier or a monochrome image carrier;
An endless transfer belt provided across a pair of spaced apart support rollers, a color image carrier on which a color image is formed across the transfer belt, and a monochrome image in which a monochrome image is formed on the surface A transfer member provided opposite to each of the carriers and transferring an image formed on each image carrier to the transfer belt, and a developed image transferred on the transfer belt from the supply unit. Switching between a secondary transfer member to be transferred to a recording medium, a color printing mode in which the color image carrier and the monochrome image carrier are in contact with the transfer belt, and a monochrome printing mode in which only the monochrome image carrier is in contact. A switching unit is disposed opposite to the monochrome image carrier via the transfer belt, and is switched to the monochrome printing mode by the switching unit. Acts on serial transfer belt, a transfer device having a belt supporting member to increase the area in contact with the monochrome image carrier of the transfer belt,
An image forming apparatus comprising:

Images