JP4850335B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and the like, and more particularly to belt deviation regulation of an image forming apparatus using a belt body such as an intermediate transfer belt.
[0002]
[Prior art]
An image forming system using an intermediate transfer member is often employed in, for example, an image forming apparatus having a full color or multiple image forming function.
[0003]
In this method, a toner image corresponding to a target full-color image or a color component image of a multicolor image is applied to a first image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric by an appropriate image forming process means. Then, the toner images of the respective colors are primarily transferred onto an intermediate transfer member as a second image carrier and sequentially superimposed to form a composite toner image corresponding to the target color image on the intermediate transfer member. To do. Next, the toner image on the intermediate transfer member is secondarily transferred to a transfer material at once, and the transfer material onto which the toner image has been transferred is introduced into a fixing device and fixed, whereby a color permanent image is formed on the transfer material. To get.
[0004]
An image forming apparatus employing a belt member as an intermediate transfer member will be described with reference to FIG. Although the image forming apparatus includes a plurality of image forming units along the intermediate transfer belt 103 of the intermediate transfer unit 100, only the image carrier and the transfer charger of one image forming unit are shown in the drawing.
[0005]
The intermediate transfer unit 100 includes an intermediate transfer belt 103, a driving roller 104 that suspends the intermediate transfer belt 103, a secondary transfer counter roller 105, a tension roller 106, and a primary transfer roller 102, and is detachable from the apparatus main body. Is installed. The tension roller 106 can swing in the vertical direction, and the tension of the intermediate transfer belt 103 is kept constant by pressing the bearing 107 of the tension roller 106 toward the outside of the intermediate transfer belt 103 with a compression spring 108. Is held in. A cleaning unit 120 for the intermediate transfer belt 103 is provided on the upstream side of the tension roller 106.
[0006]
To form an image, a toner image corresponding to the color component image of the target full-color image is formed on the photosensitive drum 101 of the image forming unit by charging, exposing and developing processes, and the toner image is transferred by the transfer roller 102 Primary transfer is performed on the intermediate transfer belt 103 at the primary transfer portion T1. This is performed in each of the plurality of image forming units to obtain a full-color image in which a plurality of color toner images are superimposed on the intermediate transfer belt 103 as a composite image corresponding to the target full-color image. This full-color image on the intermediate transfer belt 103 is secondarily transferred collectively to the transfer material P as a recording material conveyed to the intermediate transfer belt 103 by the secondary transfer roller 118 at the secondary transfer portion T2, and is not shown. If a full-color image is fixed on the transfer material P with a container, a full-color permanent image is obtained on the transfer material P.
[0007]
Untransferred toner remaining on the intermediate transfer belt 103 without being transferred by the secondary transfer is removed by the cleaning unit 120. In the cleaning unit 120, a cleaning blade 121 is held in a cleaner container 122. The blade 121 abuts against the surface of the intermediate transfer belt 103 to remove residual toner, and the transfer with the cleaner container 122 removed. Accommodates remaining toner. In the cleaner container 122, seal members 123 that prevent leakage of the removed toner to the outside of the cleaner container 122 are provided in the vicinity of both ends of the cleaning blade 121. Further, a backup roller 111 is disposed inside the intermediate transfer belt 103 at a portion facing the cleaning blade 121. The cleaning unit 120 and the backup roller 111 are fixed to the apparatus main body or the intermediate transfer unit 100.
[0008]
[Problems to be solved by the invention]
By the way, the intermediate transfer belt 103 is provided with a deviation regulating means for regulating movement (deviation) in the width direction perpendicular to the traveling direction of the intermediate transfer belt 103. As shown in FIG. 17, this deviation regulating means includes guide ribs 109 made of rubber or the like provided on both edges of the back surface side (inner side) of the intermediate transfer belt 103, and suspension rollers of the intermediate transfer belt 103. In the present example, at least one flange 110 has inclined flanges 110 provided at both ends of the tension roller 106.
[0009]
If the alignment of the three rollers 104 to 106 that suspend the intermediate transfer belt 103 is out of alignment, the accuracy of the intermediate transfer unit frame (not shown) that supports the rollers is low, or if twisting occurs, the intermediate transfer belt 103 may be displaced. As the force in the direction increases, the intermediate transfer belt 103 tends to move in the width direction, but one guide rib 109 of the intermediate transfer belt 103 hits the corresponding flange 110 of the tension roller 106 and the intermediate transfer belt 103 The shift is regulated.
[0010]
However, when the shifting force becomes extremely large, the guide rib 109 climbs up and climbs up the inclination of the flange 110 as shown in FIG. For this reason, there is a problem that the running of the intermediate transfer belt 103 meanders, the transfer position of each color toner image is shifted, and the quality of the color image is deteriorated.
[0011]
The above problem of misregistration occurs even in a monochrome image such as black and white although the influence is not as great as that of a color image. Furthermore, the same occurs when an image is directly formed on the photosensitive belt or when an image on the photosensitive drum is transferred to a transfer material on the transfer belt.
[0012]
Accordingly, an object of the present invention is to form an image with a simple structure and low cost, which can surely prevent a belt body such as an intermediate transfer belt from being displaced, and can obtain a high-quality image such as a color image without misalignment. Is to provide a device.
[0013]
[Means for Solving the Problems]
  The above object is achieved by the image forming apparatus according to the present invention..
[0015]
  In summary, the present invention provides a plurality of rollers, an endless belt body suspended on the plurality of rollers, and the back surface of the belt body.Provided inThe belt body is restricted from moving in the width direction by contacting the end of a predetermined roller.forA belt unit comprising a regulating member;
  A cleaning blade that contacts the surface of the belt body and scrapes off the toner adhering to the surface of the belt body;
In an image forming apparatus having
  The cleaning blade is opposed to the predetermined roller via the belt body, and the entire width direction of the cleaning blade is within the width of the predetermined roller.
  Abuts against the widthwise end of the cleaning bladeOuter in the width direction than the width direction end of the cleaning bladesoA pressing member that presses the belt body surface;
  While the pressing member is in contact with the widthwise end of the cleaning blade,When one end of the regulating member comes into contact with the predetermined roller due to the movement of the belt body in the width directionThrough the belt bodyOne end of the regulating member in contact with the predetermined rollerTheThe position of the regulating member by pressingTheRegulationDoAn image forming apparatus characterized by the above.
[0016]
  According to the present invention, a plurality of the restricting members are provided on the back surface of the belt body so as to be able to come into contact with both end portions of the predetermined roller. The pressing member is outside in the width direction than both ends in the width direction of the cleaning blade.The position where the cleaning blade comes into contact with both ends in the width directionAre provided respectively. The predetermined roller includes a flange at an end, and the restricting member can contact the flange. The predetermined roller is provided with flanges at both ends, and a plurality of the regulating members are provided so as to abut against the flanges. The pressing member is outside in the width direction than both ends in the width direction of the cleaning blade.The position where the cleaning blade comes into contact with both ends in the width directionAre provided respectively. In the width direction of the belt body, the width of the roller main body not including each flange of the predetermined roller is L, the width of each flange up to the position where the restricting member abuts is F, and the width of each restricting member is G When the total width of each pressing member and the cleaning blade is B,
L + 2F ≦ B ≦ L + 2F + 2G
The relationship holds. The flange was inclined so as to have a small diameter toward the outside. The flange has substantially the same diameter as the roller body. The flange is made of resin. The restriction member is formed of a viscoelastic body.
[0017]
  tonerAn image bearing member for carrying an image, and the image on the image bearing member is transferred to the belt member;tonerThe image is transferred to a transfer material. A plurality of image carriers, and a plurality of colors on the plurality of image carrierstonerThe image is sequentially transferred onto the belt body, and a plurality of colors on the belt body are transferred.tonerThe image is transferred to a transfer material. The belt body is a photoconductor. The belt body has a plurality of colors.tonerImages are formed in sequence.tonerHaving an image carrier for carrying an image, on the image carriertonerThe image is transferred to a transfer material carried on the belt body. A plurality of image carriers, and a plurality of colors on the plurality of image carrierstonerThe image is sequentially transferred onto the transfer material carried on the belt body.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.
[0019]
Example 1
FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention.
[0020]
The image forming apparatus is configured as a color laser printer which is one form of a color image forming apparatus. First, the overall configuration of the color laser printer will be described with reference to FIG.
[0021]
The color laser printer includes four color image forming units of yellow (Y), magenta (M), cyan (C), and black (K) installed along the intermediate transfer belt 18, and each image forming unit forms the color laser printer. The toner images of the respective colors are multiplex-transferred onto the intermediate transfer belt 18 and then transferred onto the transfer material in a batch to fix the transfer material onto which the four color toner images have been transferred, thereby obtaining a full-color permanent image on the transfer material. is there.
[0022]
The intermediate transfer belt 18 is suspended and installed on three rollers, that is, a drive roller 14, a secondary transfer counter roller 15, and a tension roller 16, and constitutes an intermediate transfer unit 13 together with the drive roller 14 and the like. The intermediate transfer belt 18 is driven to rotate in the direction of the arrow in the figure by driving by the driving roller 14.
[0023]
Each image forming unit includes a drum-type electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 1 (1Y, 1M, 1C, 1K), a surrounding charging roller 5 (5K, 5M, 5C, 5K), a developing device. 4 (4Y, 4M, 4C, 4K), and a drum cleaner (not shown), a laser scanner 6 (6Y, 6M, 6C, 6K) is provided above each photosensitive drum 1, and below each photosensitive drum 1. A primary transfer charger (not shown) facing the photosensitive drum 1 across the intermediate transfer belt 18 is disposed. Among these, the photosensitive drum 1, the charging roller 5, the developing device 4, and the drum cleaner are integrated in the holder container 3 (3Y to 3K) and are detachably installed in the printer main body. The process unit is replaceable.
[0024]
The photosensitive drum 1 has an organic photoconductor layer coated on the outside of an aluminum cylinder. The photosensitive drum 1 is rotatably supported by the holder container 3 and is driven to rotate counterclockwise in the drawing by transmitting a driving force from a driving motor (not shown) at one end at the rear of the drawing at the time of image formation. . The charging roller 5 is a contact-type charging unit, and applies a voltage to the charging roller 5 in contact with the surface of the photosensitive drum 1 to uniformly charge the surface of the photosensitive drum 1 to a predetermined polarity and potential.
[0025]
The laser scanner 6 as exposure means includes a laser diode (not shown), a polygon mirror 6a (6Ya, 6Ma, 6Ca, 6Ka), an imaging lens (6Yb, 6Mb, 6Cb, 6Kb) and the like. When an image signal is applied to the laser diode, the laser diode irradiates the polygon mirror 6a with image light corresponding to the image signal, and the polygon mirror 6a that rotates at high speed by the scanner motor reflects the image light and rotates at a constant speed. The surface of the drum 1 is selectively exposed through the imaging lens 6b, and an electrostatic latent image is formed on the surface of the photosensitive drum 1 by image light.
[0026]
The developing device 4 has a sleeve 4S (4YS, 4MS, 4CS, 4KS) disposed at a position facing the photosensitive drum 1 with a minute interval, and yellow (Y), magenta (M), cyan (C), respectively. ), A black (K) developer, in this example, a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed. Each developing device 4 feeds the stored developer to the sleeve 4S by a feed mechanism, coats the developer on the surface of the sleeve 4S rotating in the clockwise direction in the figure, and the coated developer is applied to the photosensitive drum 1 by the sleeve 4S. The electrostatic latent image formed on the photosensitive drum 1 is developed with a corresponding color developer and visualized as a toner image.
[0027]
The toner images of the respective colors on the photosensitive drum 1 are transferred while being superimposed on the intermediate transfer belt 18. In this embodiment, the intermediate transfer belt 18 is a seamless resin belt having a circumferential length of about 1000 mm. The intermediate transfer belt 18 is supported by the printer main body with the driving roller 14 as a fulcrum, and transmits the driving force of a driving motor (not shown) at one end on the rear side of the driving roller 14 in the drawing, so that the photosensitive drum 1 is subjected to an image forming operation. In synchronization with the peripheral speed, the intermediate transfer belt 18 is rotated clockwise in the figure. Further, the intermediate transfer belt 18 can be easily attached to and detached from the unit 13 in the right direction in the drawing.
[0028]
Below the intermediate transfer belt 18, a cassette 7 containing a plurality of transfer materials P is installed. This cassette 7, the paper feed roller 8, the feed roller 9, the double feed prevention retard roller 10, the paper feed The guide plate 11, the conveyance roller 61, and the registration roller pair 12 constitute a paper feeding unit. At the time of image formation, the paper feed roller 8 is driven and rotated in accordance with the image forming operation, and the transfer material P in the cassette 7 is separated and fed one by one. It reaches the registration roller pair 12 via the roller 61 and the like. During the image forming operation, the registration roller pair 12 performs a non-rotation operation for causing the transfer material P to stand still and a rotation operation for conveying the transfer material P toward the intermediate transfer belt 18 in a predetermined sequence. The image and the transfer material P at the time of the transfer process are aligned.
[0029]
A swingable transfer roller 60 is installed on the surface side of the intermediate transfer belt 18 at the location of the secondary transfer counter roller 15 to form a secondary transfer portion T2. The transfer roller 60 is formed by winding a metal shaft with a medium resistance foamed elastic body, can swing up and down in the figure, and is rotationally driven by a driving force to the metal shaft. As shown by the dotted line in the figure, the toner image on the intermediate transfer belt 18 is not disturbed until the toner image on the intermediate transfer belt 18 reaches the secondary transfer portion T2 while the four-color toner image is formed on the intermediate transfer belt 18. The transfer roller 60 is positioned below and is separated from the intermediate transfer belt 18. Thereafter, the transfer roller 60 is moved to an upper position indicated by a solid line in the drawing by a cam member (not shown) in accordance with the timing at which the color image is transferred to the transfer material P, and is transferred to the intermediate transfer belt 18 via the transfer material P. It is pressed with the pressure of
[0030]
At the same time, a bias is applied to the transfer roller 60, and the toner image on the intermediate transfer belt 18 is transferred to the transfer material P. Since the intermediate transfer belt 18 and the transfer roller 60 are respectively driven, the transfer material P sandwiched between the two is conveyed at a predetermined speed in the left direction in the drawing at the same time as the next process. It is sent toward the fixing device 50.
[0031]
The fixing device 50 fixes the toner image transferred onto the transfer material P. As shown in FIG. 1, the fixing device 51 applies heat to the transfer material P, and the transfer material P is pressed against the fixing roller 51. A pressure roller 52 for rotating the rollers 51 and 52. Each of the rollers 51 and 52 is formed hollow and has a heater (not shown) inside. The transfer material P to which the toner image has been transferred is nipped and conveyed by the fixing roller 51 and the pressure roller 52, and the toner image is fixed to the transfer material P by applying heat and pressure therebetween.
[0032]
Further, the intermediate transfer belt 18 is provided with a tension applying mechanism using a compression spring 21 at the tension roller 16, whereby the circumference of the intermediate transfer belt 18 is changed due to temperature and humidity changes in the printer main body and time. Even if the length changes, the tension of the intermediate transfer belt 18 is kept constant.
[0033]
As shown in FIG. 2, the tension applying mechanism compresses between the end surface 22b of the tension bearing 22 in which the shaft 16a of the tension roller 16 is rotatably fitted and the wall surface 23b of the frame 23 of the intermediate transfer unit 13. The spring 21 is attached with a predetermined pressure. The shaft 16 a of the tension roller 16 is further supported by a tensioner 17. A conductive polyacetal resin is used as the material of the tension bearing 22, and the tension roller 16 is electrically grounded. Although the tension roller shaft 16a and the tensioner 17 rotate and slide, the load applied to the inner wall of the bearing portion of the tensioner 17 is reduced, and the wear on the inner wall becomes almost zero.
[0034]
On the other hand, the inner wall 22a of the tension bearing 22 and the tension roller shaft 16a are worn, but there is no change in the positional relationship between the tensioner 17 and the tension roller 16, and the tension roller 16 and the blade 31 of the cleaning unit 30 in FIG. The relative positional relationship does not change. Further, although the mounting dimensions of the compression spring 21 slightly change due to wear of the tension bearing inner wall 22a and the tension roller shaft 16a, the intermediate transfer belt 18 does not slip due to a pressure drop due to the change.
[0035]
In this embodiment, the conductive polyacetal resin is used for the tension bearing 22, but the same effect can be obtained even when, for example, an iron-based or copper-based oil-impregnated sintered material is used.
[0036]
Further, in order to restrict the movement in the width direction, that is, the deviation, the intermediate transfer belt 18 is provided with a deviation regulating means similar to the conventional one. This deviation regulating means is, as shown in FIG. The rubber guide ribs 19 are provided over the entire circumference at both edges of the back surface 18 and the flanges 20 are formed of resin at both ends of the tension roller 16 and have an inclination. The guide ribs 19 were attached to both edges on the back side of the intermediate transfer belt 18 with an adhesive. When the shifting force of the intermediate transfer belt 18 increases and the intermediate transfer belt 18 tries to move in the width direction, one guide rib 19 of the intermediate transfer belt 18 hits the corresponding flange 20 of the tension roller 16 and the intermediate transfer belt 18 is moved. The deviation of the belt 18 is restricted.
[0037]
  A cleaning unit 30 is installed on the intermediate transfer belt 18. This cleaningunitAs shown in FIG. 3, 30 includes a cleaning blade 31, a pressure spring 36 that presses the blade 31 against the intermediate transfer belt 18, and a cleaner container 34 that holds them.
[0038]
The toner scraped off by the cleaning blade 31 is collected as a waste toner in a cleaner container 34 and sent by a screw 35 installed at the bottom of the cleaner container 34 to be a waste toner box 40 installed separately in the apparatus main body. Is housed in. The screw 35 is rotated in a direction in which waste toner is conveyed by transmitting a driving force of a driving motor (not shown) at one end at the rear of the drawing. In order to simplify the structure by reducing the number of motors, the driving source of the screw 35 uses the driving source of the fixing device.
[0039]
Further, a squeeze sheet 38 that is in contact with the intermediate transfer belt 18 is installed in parallel with the blade 31 on the upstream side of the cleaning blade 31 of the cleaner container 34. The squeeze sheet 38 is affixed to the sheet metal 39 with double-sided tape, and the sheet metal 39 is affixed to the cleaner container 34 with double-sided tape.
[0040]
The cleaning unit 30 will be further described later.
[0041]
An operation when image formation is performed by the printer configured as described above will be described.
[0042]
First, the sheet feeding roller 8 shown in FIG. 1 is rotated to separate one transfer material P in the sheet feeding cassette 1 and conveyed to the registration roller pair 12. On the other hand, the photosensitive drum 1 and the intermediate transfer belt 18 are each rotated at a predetermined peripheral speed V (same speed as the process speed) in the direction of the arrow in the figure.
[0043]
Next, when an arbitrary point in the circumferential direction of the intermediate transfer belt 18 comes to the position S (S1, S2, S3, S4) in the figure, the photosensitive drum 1 whose surface is uniformly charged becomes E (EY) in the figure. , EM, EC, EK) is subjected to laser exposure, and image formation is started. The distance from the exposure position E (image writing start position) of the photosensitive drum 1 to the contact portion (primary transfer portion) T1 (T1Y, T1M, T1C, T1K) with the intermediate transfer belt 18 counterclockwise, and the intermediate transfer The distances from S to T1 of the belt 18 are equal. Therefore, when the image writing start point E on the photosensitive drum 1 reaches the position T1, the point S on the intermediate transfer belt 18 reaches the position T1, and at that position. Match. By transferring the toner image from the photosensitive drum 1 to the intermediate transfer belt 18, an image is formed on the intermediate transfer belt 18 in the downstream direction with the S point as a leading end.
[0044]
The image is formed in the order of yellow, magenta, cyan, and black.
[0045]
First, a yellow image laser is irradiated by the scanner 6Y to form a yellow latent image on the photosensitive drum 1Y. At the same time as the latent image formation, the yellow developing device 4Y is driven, and the charging polarity of the photosensitive drum 1Y is approximately the same. A voltage of the same potential is applied to the sleeve 4YS of the developing device 4Y, yellow toner is attached to the latent image on the photosensitive drum 1Y and developed, and visualized as a yellow toner image. Subsequently, the yellow toner image on the photosensitive drum 1Y is primarily transferred onto the surface of the intermediate transfer belt 18 at the primary transfer portion T1Y slightly downstream of the developing portion. At this time, the intermediate transfer belt 18 is subjected to primary transfer by applying a voltage opposite to that of yellow toner through a primary transfer charger (not shown).
[0046]
When the image to be formed is A3 size, the length is 420 mm. The image of A3 is formed from the point S1 of the intermediate transfer belt 18 in the downstream direction to the point L1.
[0047]
Next, when the point S1 (the leading edge of the yellow image) on the intermediate transfer belt 18 reaches the position S2 in the figure, similarly to the case of yellow, the photosensitive drum 1M is irradiated with laser by the scanner 6M to form a latent image of the magenta image. The latent image is developed by the magenta developing device 4M to be visualized as a magenta toner image, and the magenta toner image is transferred onto the intermediate transfer belt 18 by superimposing the yellow toner image on the intermediate transfer belt T1M.
[0048]
Similarly, when S1 (the leading edge of yellow and magenta image) on the intermediate transfer belt 18 reaches the position of S3 in the figure, the scanner 6C irradiates the photosensitive drum 1M with a laser beam of a cyan image to form a latent image. The latent image is developed by the cyan developing device 4C to form a cyan toner image, and transferred to the yellow and magenta toner images on the intermediate transfer belt 18 by the primary transfer portion T1C.
[0049]
Similarly, when S1 (the leading edge of the yellow, magenta, and cyan images) on the intermediate transfer belt 18 reaches the position of S4 in the figure, the scanner 6K irradiates the photosensitive drum 1K with laser light of a black image to form a latent image. The latent image is developed by the black developing device 4K to form a black toner image, and is transferred onto the intermediate transfer belt 18 by superimposing the yellow, magenta, and cyan toner images on the primary transfer portion T1K.
[0050]
  As described above, latent image formation, development, and primary transfer are performed in the order of yellow, magenta, cyan, and black, and yellow, magenta are formed on the surface of the intermediate transfer belt 18.TheA full-color image in which toner images of four colors of cyan and black are superimposed is formed.
[0051]
Before the transfer of the four-color black toner image to the intermediate transfer belt 18 is completed, the leading edge of the four-color superimposed toner image on the intermediate transfer belt 18 (at the position S1 of the intermediate transfer belt) is 2 Along with reaching the next transfer portion T2, the transfer material P that has been kept on standby by the registration roller pair 12 is conveyed to the transfer portion T2 at a predetermined timing. At the same time, the transfer roller 60 that is separated from the intermediate transfer belt 18 and is waiting below is moved upward by the cam mechanism, and the transfer roller 60 is moved to the intermediate transfer belt 18 at the transfer portion T2 with the transfer material P interposed therebetween. Simultaneously with the press contact, a bias having a reverse characteristic to the toner is applied to the transfer roller 60, and the four color toner images on the intermediate transfer belt 18 are secondarily transferred onto the transfer material P all at once.
[0052]
The transfer material P onto which the four color toner images have been transferred through the secondary transfer portion T2 is peeled off from the intermediate transfer belt 18 and conveyed to the fixing device 50, where the toner images are fixed to form a full-color permanent image. Thereafter, the sheet is discharged onto the discharge tray 65 at the upper part of the apparatus main body through the three discharge roller pairs 62, 63, 64, and the image forming operation is completed.
[0053]
Untransferred toner remaining on the intermediate transfer belt 18 without being transferred in the secondary transfer is removed by the blade 31 of the cleaning unit 30 in contact with the surface of the intermediate transfer belt 18, and the removed transfer residual toner is removed from the cleaner. Housed in a container 34.
[0054]
In the present invention, in order to realize reliable prevention of the shift of the intermediate transfer belt 18 with a simple configuration and at low cost, the guide ribs 19 on both edges of the back surface of the intermediate transfer belt 18 and both ends of the tension roller 16 are provided. In addition to the deviation restricting means by the flange 20, the cleaning unit 30 is installed at a position facing the tension roller 16, and the cleaning unit 30 has an auxiliary function for regulating the deviation. This will be described below.
[0055]
As described above, the cleaning unit 30 includes the cleaning blade 31, the pressure spring 36 that presses the blade 31 against the intermediate transfer belt 18, and the cleaner container 34 that holds them. In the present invention, the cleaning unit 30 is installed at a position facing the tension roller 16 with the intermediate transfer belt 18 sandwiched therebetween as described above.
[0056]
The cleaning blade 31 is made of urethane rubber formed on a metal plate 33 in a plate shape, and is pressed against the intermediate transfer belt 18 by a pressurizing spring 36 at a predetermined angle with a shaft 32 held in a cleaner container 34 as a rotation center. By being applied, the intermediate transfer belt 18 is uniformly contacted. The tension roller 16 is positioned on the opposite portion of the cleaning blade 31 to serve as a backup roller, and allows the cleaning blade 31 to contact the intermediate transfer belt 18 with a predetermined contact pressure. The transfer residual toner on the intermediate transfer belt 18 is scraped off at the point where the cleaning blade 31 comes into contact, and the intermediate transfer belt 18 is cleaned.
[0057]
The toner scraped off by the cleaning blade 31 is collected as a waste toner in the cleaner container 34 and then sent by a screw 35 installed at the bottom of the cleaner container 34 to be separately disposed in the apparatus main body. The box 40 is housed as described above.
[0058]
A major feature of the present invention is that, in order to prevent the guide rib 19 from climbing onto the flange 20 when a biasing force is generated on the intermediate transfer belt 18, as shown in FIGS. That is, end pressing members (pressing members) 37 located outside both ends are installed.
[0059]
The end pressing member 37 is formed of an elastic body such as sponge, and in this embodiment, the end pressing member 37 is formed in a form in which a PTFE fiber pile is bonded onto malt plane. The end pressing member 37 was installed in the cleaner container 34 so as to have the above arrangement.
[0060]
The presser member 37 also serves as an end seal member of the cleaning blade 31, closes a gap between the cleaner container 34 outside the both ends of the cleaning blade 31 and the intermediate transfer belt 18, and is scraped off by the blade 31. This also serves to prevent the waste toner from scattering or leaking out of the cleaning unit 30 and to more reliably collect the toner in the cleaner container 34.
[0061]
When the life of the cleaning unit 30 does not match the life of the intermediate transfer belt 18, it is inefficient to replace both the intermediate transfer unit 13 and the cleaning unit 30 at the same time. Has been.
[0062]
First, a method for setting the cleaning unit 30 to the intermediate transfer unit 13 will be described.
[0063]
As shown in FIG. 4, the intermediate transfer unit 13 is provided with two bosses 24 and 24 ′ for positioning the cleaning unit 30. The bosses 24 and 24 'are formed integrally with the tensioners 17 and 17' at both ends of the tension roller 16. Even if the tension roller 16 moves, the axis 0 of the tension roller shaft 16a and the bosses 24 at both ends The line 0 ′ connecting the 24 ′ axes is always kept parallel. One of the tensioners 17 and 17 'on the rear side of the figure is provided with a round slot 25 into which the screw drive input portion 41 of the cleaning unit 30 is fitted, and serves as a detent when the cleaning unit 30 is set. Fulfill.
[0064]
Further, the cleaning unit 30 has a front detent member 42 in the figure, and this detent member 42 is positioned on one of the tensioners 17 at the front of the figure. As shown in FIG. 5, the cleaning unit 30 is provided with positioning grooves 43 and 43 ′. The positioning grooves 43 and 43 ′ are fitted into the bosses 24 and 24 ′. The cleaning unit 30 can be positioned on the intermediate transfer unit 13 by hooking 24, 24 ′.
[0065]
First, as shown in FIGS. 4 and 6, the cleaning unit 30 is inserted into the intermediate transfer unit 13 from the front of FIG. Push until it hits the part (not shown). Next, in the pushed state, as shown in FIGS. 7 and 8, the lever 46 provided in the cleaning unit 30 is held and rotated around the axis of the waste toner conveying screw 35 and latched to the bosses 24 and 24 ′. The cleaning unit 30 is set in the intermediate transfer unit 13 by pushing up until 44 and 44 ′ are caught.
[0066]
On the contrary, when the cleaning unit 30 is taken out, the latches 44 and 44 ′ are released by the lever 46 that also serves to release the latch, the cleaning unit 30 is separated from the intermediate transfer unit 13, and is pulled out forward in the drawing.
[0067]
The operation of the end pressing member 37 will be described. FIG. 9 shows the positional relationship between the guide rib 19, the end pressing member 37, and the flange 20 when the cleaning unit 30 is set in the intermediate transfer unit 13.
[0068]
In FIG. 9, the width of the roller main body portion not including the flange 20 of the tension roller 16 is L, the linear length of the flange 20 up to the position where the guide rib 19 abuts by movement in the width direction is F, and the width of the guide rib 19 is G. Let B be the length between the outer end surfaces of the end pressing members 37 at both ends of the blade 31.
[0069]
In the present invention, the end pressing member 37 is caught on the guide rib 19 in a state where the guide rib 19 hits the flange 20 by the movement in the width direction on the intermediate transfer belt 18, but the end pressing member 37 does not protrude from the guide rib 19. Of condition
L + 2F ≦ B ≦ L + 2F + 2G
Each member was arranged so that the above relationship was established.
[0070]
According to this, the end pressing members 37 disposed at both ends of the cleaning blade 31 are disposed at a position straddling the guide rib 19 and the flange 20 at both ends of the tension roller 16 with the intermediate transfer belt 18 interposed therebetween. As shown in FIG. 4, even if the intermediate transfer belt 18 moves to the right in the direction toward the left side and the left guide rib 19 hits the flange 20 and tries to ride on the flange 20, the end presser member 37 holds the guide rib 19 on the foot. Is included. Therefore, the deviation control of the intermediate transfer belt 18 by the guide rib 19 and the flange 20 can be reliably performed.
[0071]
When the above condition is not satisfied and B> L + 2F + 2G, as shown in FIG. 11, the end pressing member 37 protrudes from the guide rib 19 that abuts against the flange 20, and the end pressing member 37 causes the intermediate transfer belt 18. The movement in the shift direction is restricted, the intermediate transfer belt is difficult to return in the reverse direction, and the shift regulation is difficult to function. Further, since stress is applied to the guide rib 19, problems such as peeling of the guide rib 19 from the intermediate transfer belt 18 occur as the use proceeds.
[0072]
Further, in the case of B <L + 2F, as shown in FIG. 12, the end pressing member 37 does not engage with the guide rib 19 that has come into contact with the flange 20, so that the riding of the guide rib 19 cannot be pressed.
[0073]
As described above, in this embodiment, since the end pressing members 37 positioned at both ends of the cleaning blade 31 are provided in the cleaning unit 30 of the intermediate transfer belt 18, they are provided at both edges on the back side of the intermediate transfer belt 18. Even if the guide rib 19 tries to ride on the flange 20 at both ends of the tension roller 16 due to the movement of the intermediate transfer belt 18 in the shifting direction, the guide rib 19 that rides on the flange 20 is pushed down by the end pressing member 37 and is pushed up. Can be prevented. Therefore, the shift regulation by the shift regulation means between the guide rib 19 and the flange 20 can be assisted so that the shift of the intermediate transfer belt 18 can be reliably controlled, meandering accompanying the shift of the intermediate transfer belt 18 can be prevented, and each color can be prevented. The toner image transfer position shift is eliminated, and a high-quality color image can be obtained. The configuration of the deviation restricting means including the auxiliary means by the end pressing member 37 is simple and low-cost, and the end pressing member 37 also serves to prevent the leakage of waste toner. There is no need to add parts or change the configuration, which is also low cost.
[0074]
In the above, the flange 20 is formed of resin at both ends of the tension roller 16, but both ends of the tension roller 16 may be processed into the same shape as the flange. In this case, a separate flange is manufactured. Since it does not need to be attached, the cost is reduced accordingly.
[0075]
Further, as shown in FIG. 13, the flange 20 may be flat without being inclined, and the end pressing member 37 and the like may be provided so that the relational expression of the above-described member arrangement: L + 2F ≦ B ≦ L + 2F + 2G is satisfied. By arranging, the same effect can be obtained.
[0076]
In the above-described embodiment, the case where the opposing roller of the cleaning blade is a tension roller has been described. However, the present invention is not limited to this. For example, a driving roller may be used. Needless to say, the opposed roller of the cleaning blade has a function of striking against the rib and regulating the deviation of the belt. That is, it is possible to prevent the rib from riding on the opposing roller at the cleaning position by the cleaning blade. Therefore, it is possible to prevent the occurrence of a cleaning failure in which the intermediate transfer belt is lifted and a gap is formed between the intermediate transfer belt and the cleaning blade, and the toner on the intermediate transfer belt passes through without being removed by the cleaning blade. can do.
[0077]
Example 2
FIG. 14 is an overall configuration diagram showing another embodiment of the image forming apparatus of the present invention.
[0078]
The image forming apparatus of this embodiment is configured as a full-color image forming apparatus using a photosensitive belt instead of a photosensitive drum. The object of shift regulation in the present invention is not limited to the intermediate transfer belt, and the present invention can also be applied to a photosensitive belt.
[0079]
In FIG. 14, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted unless necessary.
[0080]
As shown in FIG. 14, the image forming apparatus includes a photosensitive belt unit 80 in which a photosensitive belt 81 is suspended from a driving roller 14, a transfer facing roller 82, and a tension roller 16. (K), cyan (C), magenta (M), and yellow (Y) four-color image forming units are provided. Each image forming unit includes a charger 5 (5K, 5C, 5M, 5Y) and a developing unit 4. (4K, 4C, 4M, 4Y), and the charger 5 and the developer 4 are integrally assembled by a holder 3 (3K, 3c, 3M, 3Y), and are detachable from the apparatus main body. Configured into units. The photosensitive belt 81 is given tension by applying pressure to the tension roller 16 with the compression spring 21.
[0081]
In each image forming unit, the photosensitive belt 81 is charged by the charger 5, exposed by the laser scanner 6, and developed by the developing device 4, and a four-color toner image is formed on the photosensitive belt 81 so as to overlap. The image is collectively transferred by the transfer roller 60 to the transfer material P conveyed from the cassette 7 to the transfer portion T1, and then fixed by the fixing device 50, so that a full-color permanent image is obtained on the transfer material P.
[0082]
Also in this embodiment, the deviation regulating means is constituted by the guide ribs 19 provided at both edge portions on the back surface side of the photosensitive belt 81 and the flanges 20 having the inclined ends of the tension roller 16 and / or flat, and the intermediate transfer belt 18. It regulates the shift. Further, the cleaning unit 30 for the photosensitive belt 81 is installed at a position opposed to the tension roller 16, and end pressing members 37 are arranged at both ends of the cleaning blade 31.
[0083]
Therefore, also in this embodiment, as in the first embodiment, the guide rib 19 is pressed by the end pressing member 37 to prevent it from climbing onto the flange 20, and the photosensitive belt 81 is provided by means for restricting the deviation between the guide rib 19 and the flange 20. The shift regulation can be surely performed, the meandering accompanying the shift of the photosensitive belt 81 can be prevented, and the formation position shift of the toner image of each color can be eliminated, and a high-quality color image can be obtained. Can do.
[0084]
Example 3
FIG. 15 is a sectional view showing still another embodiment of the image forming apparatus of the present invention.
[0085]
This embodiment was applied to a color image forming apparatus having a transfer belt that carries a transfer material and conveys it to each image forming unit. In FIG. 15, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted unless necessary.
[0086]
As shown in FIG. 15, the image forming apparatus includes a transfer belt unit 90 in which a transfer belt 91 is suspended from a drive roller 14, a support roller 92, and a tension roller 16, and black ( K), cyan (C), magenta (M), and yellow (Y) image forming units, each of which includes a photosensitive drum 1 (1K, 1C, 1M, 1Y) and a charging roller 5 ( 5K, 5C, 5M, 5Y), a developing device 4 (4K, 4C, 4M, 4Y) and a drum cleaner (not shown). The photosensitive drum 1, the charging roller 5, the developing device 4, and the drum cleaner are provided in a holder container 3 (3Y). ˜3K) are integrated into a process unit that is detachable from the printer body. The transfer belt 91 is given tension by applying pressure to the tension roller 16 with the compression spring 21.
[0087]
In each image forming unit, the photosensitive drum 1 is charged by the charger 5, exposed by the laser scanner 6, and developed by the developing device 4 to form toner images of respective colors superimposed on the photosensitive drum 1. The image is transferred onto the transfer material P carried on each transfer portion T1 (T1K, T1C, T1M, T1Y) by the transfer roller 60 (60K, 60C, 60M, 60Y). And a full-color permanent image is obtained on the transfer material P.
[0088]
Also in this embodiment, the deviation regulating means is constituted by the guide ribs 19 provided at both edges on the back surface side of the transfer belt 91 and the flanges 20 having inclinations at both ends of the tension roller 16 and / or flat, and Regulates close. In addition, the cleaning unit 30 for the transfer belt 91 is installed at a position opposite to the tension roller 16, and end pressing members 37 are disposed at both ends of the cleaning blade 31.
[0089]
Accordingly, in this embodiment as well, as in the first embodiment, the guide rib 19 is pressed by the end pressing member 37 to prevent it from climbing onto the flange 20, and the transfer belt 91 by the deviation regulating means between the guide rib 19 and the flange 20 is used. The shift regulation can be surely performed, the meandering accompanying the shift of the transfer belt 91 is prevented, the transfer position deviation of the toner images of the respective colors onto the transfer material P is eliminated, and the high quality is achieved. A color image can be obtained.
[0090]
In each of the above-described embodiments, an image forming apparatus that forms a color image of a plurality of colors has been described. However, the present invention is not limited to this, and a monochrome image using a belt body such as an intermediate transfer belt. The present invention can also be applied to an image forming apparatus that forms the image.
[0091]
【The invention's effect】
As described above, according to the present invention, the deviation regulating means is configured by the guide ribs provided on both edges of the back surface side of the belt body such as the intermediate transfer belt, and the flanges at both ends of the tension roller of the belt body. When regulating the deviation of the belt body, the belt body cleaning device is installed at the position opposite to the tension roller, and the cleaning device is provided with end pressing members positioned at both ends of the cleaning member so as to press the guide rib. As a result, the movement of the belt body in the shift direction can prevent the guide rib from riding on the flange, and the belt body shift regulation can be performed reliably. Accordingly, it is possible to obtain a high-quality image such as a color image in which the meandering of the belt body is prevented and a shift in the transfer position of each color toner image is eliminated. Also, the configuration of the deviation regulating means including the end pressing member is simple and low cost.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention.
2 is a perspective view showing a tension applying mechanism of an intermediate transfer belt installed in the image forming apparatus of FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing installation of a deviation regulating means and a cleaning unit to the intermediate transfer belt in the present invention.
FIG. 4 is a perspective view showing a relationship between an intermediate transfer belt unit and a cleaning unit in the present invention.
5 is a plan view showing the cleaning unit of FIG. 4. FIG.
6 is a cross-sectional view showing a method for attaching and detaching the cleaning unit of FIG. 4;
7 is a cross-sectional view showing a continuation of the method for attaching and detaching the cleaning unit of FIG. 4;
8 is a cross-sectional view showing a continuation of the method for attaching and detaching the cleaning unit of FIG.
FIG. 9 is a cross-sectional view showing a positional relationship among a guide rib of an intermediate transfer belt, an end pressing member of a cleaning unit, and a flange of a tension roller in the present invention.
10 is a cross-sectional view showing a state in which the guide rib of FIG. 9 is in contact with a flange.
11 is a cross-sectional view showing a state in which the end pressing member and the like shown in FIG. 9 are improperly arranged and the end pressing member protrudes from the intermediate transfer belt. FIG.
12 is a cross-sectional view showing a state in which the end pressing member and the like shown in FIG. 9 are improperly arranged and the end pressing member cannot press the riding on the flange of the guide rib.
FIG. 13 is a cross-sectional view showing a tension roller having an inclined flange that can be used in the present invention.
FIG. 14 is an overall configuration diagram showing another embodiment of the image forming apparatus of the present invention.
FIG. 15 is an overall configuration diagram showing still another embodiment of the image forming apparatus of the present invention.
FIG. 16 is a cross-sectional view illustrating installation of an intermediate transfer belt shift regulating unit and a cleaning unit in a conventional image forming apparatus.
17 is a cross-sectional view showing a state in which the guide rib of the shift regulating means in FIG. 16 has come into contact with the flange of the tension roller.
18 is a cross-sectional view showing a state where the guide rib of FIG. 17 rides on the flange.
[Explanation of symbols]
13 Intermediate transfer unit
14 Drive roller
16 Tension roller
17 Tensioner
18 Intermediate transfer belt
19 Guide rib
20 Flange
30 Cleaning unit
31 Cleaning blade
34 Cleaner container
37 End holding member

Claims (17)

A plurality of rollers, an endless belt body suspended from the plurality of rollers, and provided on the back surface of the belt body, the movement of the belt body in the width direction is regulated by contacting an end portion of a predetermined roller. A belt unit comprising a regulating member for
A cleaning blade that contacts the surface of the belt body and scrapes off the toner adhering to the surface of the belt body;
In an image forming apparatus having
The cleaning blade is opposed to the predetermined roller via the belt body, and the entire width direction of the cleaning blade is within the width of the predetermined roller.
A pressing member that comes into contact with the widthwise end of the cleaning blade and presses the surface of the belt body on the outer side in the widthwise direction than the widthwise end of the cleaning blade;
The pressing member is in contact with the end portion in the width direction of the cleaning blade, and when the one end of the regulating member comes into contact with the predetermined roller by the movement in the width direction of the belt body, the belt member is interposed through the belt body. image forming apparatus characterized by regulating the position of the regulating member by pressing one end of the regulating member in contact with the predetermined roller.   2. The image forming apparatus according to claim 1, wherein a plurality of the regulating members are provided on the back surface of the belt body so as to be able to come into contact with both end portions of the predetermined roller. 3. The pressing member according to claim 2, wherein the pressing member is provided at a position in contact with both ends in the width direction of the cleaning blade on the outer side in the width direction than both ends in the width direction of the cleaning blade . Image forming apparatus.   4. The image forming apparatus according to claim 1, wherein the predetermined roller includes a flange at an end portion, and the restriction member is capable of contacting the flange. 5.   The image forming apparatus according to claim 1, wherein the predetermined roller includes flanges at both ends, and a plurality of the regulating members are provided so as to abut each of the flanges. The said pressing member is each provided in the position which contact | abuts the width direction both ends of the said cleaning blade on the outer side in the said width direction rather than the width direction both ends of the said cleaning blade , respectively. Image forming apparatus. In the width direction of the belt body, the width of the roller main body not including each flange of the predetermined roller is L, the width of each flange up to the position where the restricting member abuts is F, and the width of each restricting member is G When the total width of each pressing member and the cleaning blade is B,
L + 2F ≦ B ≦ L + 2F + 2G
The image forming apparatus according to claim 6, wherein:   The image forming apparatus according to claim 5, wherein the flange is inclined so as to have a small diameter toward the outside.   The image forming apparatus according to claim 5, wherein the flange has substantially the same diameter as the roller main body.   The image forming apparatus according to claim 4, wherein the flange is made of resin.   The image forming apparatus according to claim 1, wherein the restricting member is formed of a viscoelastic body.   2. An image carrier that carries a toner image, wherein the image on the image carrier is transferred to the belt member, and the toner image on the belt member is transferred to a transfer material. The image forming apparatus according to claim 11.   A plurality of image carriers, and a plurality of color toner images on the plurality of image carriers are sequentially transferred to the belt member, and a plurality of toner images on the belt member are transferred to a transfer material; The image forming apparatus according to claim 13.   The image forming apparatus according to claim 1, wherein the belt member is a photosensitive member.   The image forming apparatus according to claim 14, wherein toner images of a plurality of colors are sequentially stacked on the belt body.   12. The image bearing member for carrying a toner image, wherein the toner image on the image carrier is transferred to a transfer material carried on the belt member. 12. 2. The image forming apparatus according to item 1.   17. The toner image according to claim 16, comprising a plurality of the image bearing members, and the toner images of a plurality of colors on the plurality of image bearing members are sequentially superimposed and transferred onto a transfer material carried on the belt member. Image forming apparatus.

Images