JP2015219465A - Cleaning device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent failure of contact between a cleaning blade and an image carrier due to formation of a protrusion part resulting from frictional resistance between the cleaning blade and image carrier.SOLUTION: A cleaning device of the application of the present invention includes: an image carrier 6; a cleaning blade 41 that is in contact with the image carrier 6 on the downstream side with respect to a transfer position to scrape off a residual material RE on the image carrier 6; and a pressing member 43 that presses a portion of the surface of the image carrier 6 on the upstream side with respect to a contact part with the cleaning blade 41.

Description

  The present invention relates to a cleaning device that removes and collects residual toner on an image carrier, and an image forming apparatus including the same. The image forming apparatus includes various apparatuses such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions in a complex manner.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a toner image formed on an image carrier (such as a photoreceptor or an intermediate transfer belt) is transferred to a recording material. When the toner image is transferred, a part of the toner may remain on the image carrier due to a mirror image force of the toner, a variation in transfer electric field, or the like. For this reason, a cleaning member is arranged on the downstream side of the transfer position on the image carrier, and residues such as residual toner and paper dust on the image carrier are removed by the cleaning member (see, for example, Patent Documents 1 and 2). . As a cleaning member, for example, a plate-like cleaning blade (hereinafter simply referred to as a blade) having elasticity such as urethane rubber is known. In this case, the residue on the image carrier is scraped off by bringing the tip end of the blade into contact with the surface of the rotating image carrier.

  By the way, for example, if the hardness of the surface of the intermediate transfer belt as an image carrier is lower than the hardness of the blade, the surface of the intermediate transfer belt is recessed by the contact pressure of the blade, and the tip corner (tip contact portion) of the blade is recessed in the recess. The phenomenon of blade turning is likely to occur when the blade is caught and the contact posture of the blade changes. In this regard, in Patent Documents 1 and 2, etc., the hardness of the surface of the intermediate transfer belt is set to be higher than the hardness of the blade, and the dent on the surface of the intermediate transfer belt due to the contact pressure of the blade is eliminated, thereby preventing the blade from turning. ing.

JP 2003-248379 A JP 2009-282175 A

  However, even if the dent on the surface of the intermediate transfer belt due to the contact pressure of the blade is eliminated, if the resistance due to friction between the blade tip corner and the surface of the intermediate transfer belt increases, the intermediate transfer belt cannot move smoothly, A portion of the transfer belt on the upstream side of the contact portion with the blade bends and rises up (is raised). If the intermediate transfer belt continues to circulate while the bulge portion is formed, the bulge portion may cause poor contact with the blade, resulting in blade turning and residue residue. .

  For example, when the blade is arranged in a counter manner with respect to the intermediate transfer belt (when the blade is laid down along the circumferential direction of the intermediate transfer belt), if the intermediate transfer belt continues to circulate with the bulge portion formed, The leading edge of the blade is lifted by the raised portion, and the contact angle between the intermediate transfer belt and the blade is increased more than usual. Then, the tip corner of the blade is pulled downstream in the circumferential direction by the surface of the intermediate transfer belt, and the blade is turned up.

In addition, for example, when the blade is arranged in a with-type manner with respect to the intermediate transfer belt (when the blade is placed so as to intersect the circumferential direction of the intermediate transfer belt), the intermediate transfer belt is circulated while the bulge portion is formed If this is continued, the leading edge of the blade is lifted by the raised portion, and this time, the contact angle between the intermediate transfer belt and the blade becomes smaller than usual. Then, the contact pressure of the blade against the intermediate transfer belt is reduced, and as a result, the residue on the intermediate transfer belt is scraped off.

  The problem caused by the formation of the above-described bulging portion does not occur only in the case of the intermediate transfer belt but can also occur in the belt-type photosensitive member.

  An object of the present invention is to provide a cleaning apparatus and an image forming apparatus that have been improved by examining the above-described present situation.

  The invention according to claim 1 relates to a cleaning device, an image carrier, a cleaning blade that contacts the downstream side of the transfer position on the image carrier and scrapes off residues on the image carrier, and the surface of the image carrier. And a pressing member that presses a portion upstream of the contact portion with the cleaning blade.

  According to a second aspect of the present invention, in the cleaning device according to the first aspect, the pressing member is at least in a sheet passing width direction in a portion of the surface of the image carrier upstream of a contact portion with the cleaning blade. It is configured to press both ends.

  A third aspect of the present invention is the cleaning apparatus according to the first or second aspect, wherein the pressing member is attached to the cleaning blade.

  According to a fourth aspect of the present invention, in the cleaning device according to the first or second aspect, the pressing member is attached to a rotation shaft of the image carrier.

  A fifth aspect of the present invention relates to an image forming apparatus, wherein the cleaning apparatus according to any one of the first to fourth aspects is provided.

  According to the present invention, the presence of the pressing member that presses the portion upstream of the contact portion with the cleaning blade on the surface of the image carrier can suppress the formation of the raised portion due to the frictional resistance. For this reason, it is possible to reliably prevent the occurrence of problems such as turning over of the blade and scraping of the residue, regardless of the arrangement form of the cleaning blade (either of the counter type or the width type).

It is a schematic explanatory drawing of a printer. It is explanatory drawing of the transfer belt cleaner in 1st Embodiment, (a) is front sectional drawing of a transfer belt cleaner, (b) is an enlarged front view of a cleaning blade and a press member. It is a side view which shows the relationship between the cleaning blade and press member in 1st Embodiment. It is front sectional drawing of the transfer belt cleaner in 2nd Embodiment. It is a side view which shows the relationship between the cleaning blade and press member in 2nd Embodiment. It is a side view which shows the relationship between the cleaning blade and press member in 3rd Embodiment. It is a side view which shows the relationship between the cleaning blade and press member in 4th Embodiment. It is front sectional drawing of the transfer belt cleaner in 5th Embodiment. It is a side view which shows the relationship between the cleaning blade and press member in 5th Embodiment. It is a side view which shows the relationship between the cleaning blade and press member in 6th Embodiment.

  Hereinafter, an embodiment in which the present invention is applied to a tandem color digital printer (hereinafter referred to as a printer), which is an example of an image forming apparatus, will be described with reference to the drawings. In addition, in the following description, when using a term indicating a specific direction or position (for example, “left / right”, “up / down”, etc.) as necessary, the direction orthogonal to the paper surface in FIG. ing. These terms are used for convenience of explanation, and do not limit the technical scope of the present invention.

(1). Overview of Printer First, an overview of the printer 1 will be described with reference to FIG. As shown in FIG. 1, the printer 1 includes an image process device 3, a paper feeding device 4, a fixing device 5, and the like in a housing 2. Although not shown in detail, the printer 1 is connected to a network such as a LAN, and is configured to execute printing based on the command when receiving a print command from an external terminal (not shown). Yes.

  The paper feeding device 4 located at the lower part in the housing 2 includes a paper feeding cassette 21 that accommodates the recording material P, a pickup roller 22 that feeds the recording material P in the paper feeding cassette 21 from the uppermost layer, and a fed recording material P. A separation roller pair 23 that separates the sheets one by one and a timing roller pair 24 that conveys the recording material P separated into one sheet to the image processing apparatus 3 at a predetermined timing are provided. The recording material P in each paper feed cassette 21 is sent out one by one from the uppermost layer to the conveyance path 30 by the rotation of the pickup roller 22 and the separation roller 23. The conveyance path 30 passes from the paper feeding cassette 21 of the paper feeding device 4 to the upper portion of the housing 2 through the nip portion of the timing roller pair 24, the secondary transfer nip portion of the image processing device 3, and the fixing nip portion of the fixing device 5. To the discharge roller pair 26 at

  The recording material P in the paper feed cassette 21 is set to a center reference that is conveyed in the direction of arrow S toward the conveyance path 30 with the center of the sheet passing width (width dimension orthogonal to the conveyance direction S) as a reference. In the embodiment, the paper feed cassette 21 is provided with a pair of side regulating plates 25 that bring the recording material P before being fed into the center reference. The pair of side portion regulating plates 25 are configured to move in close proximity to each other in the sheet passing width direction (direction perpendicular to the transport direction S). By sandwiching the recording material P in the paper feed cassette 21 from both sides in the sheet passing width direction by the pair of side portion regulating plates 25, the recording material P in the paper feed cassette 21 is set to the center reference regardless of the standard. . Therefore, the transfer process in the image processing apparatus 3 and the fixing process in the fixing apparatus 5 are also executed on the basis of the center.

The image processing device 3 positioned above the paper feeding device 4 plays a role of transferring a toner image formed on a photosensitive drum 13 which is an example of an image carrier to a recording material P, and an intermediate transfer belt. 6 and a total of four image forming sections 7 corresponding to the respective colors of yellow (Y), magenta (M), cyan (C) and black (K). The intermediate transfer belt 6 is also an example of an image carrier, and is wound around a driving roller 8 located on the right side of the central part in the housing 2 and a driven roller 9 located on the left side of the central part. A secondary transfer roller 10 is disposed outside the portion of the intermediate transfer belt 6 that is wound around the drive roller 8. A contact portion between the intermediate transfer belt 6 and the secondary transfer roller 10 is a secondary transfer nip portion which is a secondary transfer region. The intermediate transfer belt 6 rotates in the counterclockwise direction in FIG. 1 by rotating the driving roller 8 counterclockwise in FIG. 1 with the rotational power of a main motor (not shown). A transfer belt cleaner 12 that removes untransferred toner on the intermediate transfer belt 6 is disposed outside the portion of the intermediate transfer belt 6 that is wound around the driven roller 9. A control unit 28 that performs overall control of the printer 1 is disposed between the image processing apparatus 3 and the sheet feeding apparatus 4 in the housing 2.

  The four image forming units 7 are arranged along the intermediate transfer belt 6 in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the left in FIG. They are arranged side by side. In FIG. 1, for convenience of explanation, symbols Y, M, C, and K are attached to the image forming units 7 according to the reproduction colors. Each image forming unit 7 includes a photosensitive drum 13. Around the photosensitive drum 13, a charger 14, an exposure unit 19, a developing unit 15, a primary transfer roller 16, and a photosensitive cleaner 17 are arranged in this order along the clockwise rotation direction in FIG. 1. A contact portion between the photosensitive drum 13 and the intermediate transfer belt 6 is a primary transfer nip portion which is a primary transfer region.

  In each image forming unit 7, when a laser beam is projected from the exposure unit 19 onto the photosensitive drum 13 charged by the charger 14, an electrostatic latent image is formed. The electrostatic latent image is reversely developed with toner supplied from the developing unit 15 to be a toner image of each color, and is transferred from the photosensitive drum 13 in the order of yellow, magenta, cyan, and black in the primary transfer nip portion. Primary transfer is performed on the outer peripheral surface of the belt 6 and overlapped. Untransferred toner remaining on the photosensitive drum 13 is scraped off by the photosensitive cleaner 17 and removed from the photosensitive drum 13. Then, when the recording material P passes through the secondary transfer nip portion, the superimposed four color toner images are secondarily transferred onto the recording material P all at once. Residues RE such as untransferred toner and paper dust remaining on the intermediate transfer belt 6 are scraped off by the transfer belt cleaner 12 and removed from the intermediate transfer belt 6.

  Note that a lubricant is added to the toner supplied from the developing unit 15, and when a toner image is formed on the photosensitive drum 13, the lubricant is also supplied to the surface of the photosensitive drum 13 together with the toner. Then, the lubricant on the photosensitive drum 13 is leveled and thinned when scraped off by the photosensitive cleaner 17.

  The fixing device 5 positioned above the secondary transfer roller 10 in the image processing apparatus 3 includes a fixing roller 31 incorporating a heat source such as a halogen lamp heater and a pressure roller 32 facing the fixing roller 31. A contact portion between the fixing roller 31 and the pressure roller 32 is a fixing nip portion which is a fixing region. The recording material P on which the unfixed toner image is passed through the secondary transfer nip portion is heated and pressurized when passing through the fixing nip portion between the fixing roller 31 and the pressure roller 32, and the recording material P An unfixed toner image is fixed thereon. Thereafter, the recording material P is discharged onto the paper discharge tray 27 by the rotation of the pair of discharge rollers 26.

(2). First Embodiment of Transfer Belt Cleaner Next, a first embodiment of a transfer belt cleaner 12 as an example of a cleaning device will be described with reference to FIGS. 2 and 3. As described above, a transfer belt cleaner as a cleaning device that removes and collects a residue RE such as untransferred toner on the intermediate transfer belt 6 outside the portion of the intermediate transfer belt 6 wound around the driven roller 9. 12 is arranged. The transfer belt cleaner 12 contacts the downstream side of the secondary transfer nip portion 11 (transfer position) of the intermediate transfer belt 6 in the housing 40 that accommodates the residue RE, and scrapes the residue RE on the intermediate transfer belt 6. A cleaning blade 41 is provided, and a recovery screw 42 that recovers the scraped residue RE.

The cleaning blade 41 is a plate having elasticity such as urethane rubber, for example, abuts on the downstream side of the secondary transfer nip portion 11 in the intermediate transfer belt 6, and intermediate transfer is performed by the rotation of the intermediate transfer belt 6. The residue RE on the belt 6 is scraped off. In the first embodiment, the tip corner of the cleaning blade 41 is in contact with the surface of the intermediate transfer belt 6. The cleaning blade 41 and the driven roller 9 are in a positional relationship such that the intermediate transfer belt 6 is sandwiched between both the rollers 41 and 9. The cleaning blade 41 of the first embodiment is arranged in a counter manner with respect to the intermediate transfer belt 6. That is, the cleaning blade 41 is laid down on the intermediate transfer belt 6 along the circumferential direction of the intermediate transfer belt 6.

  The length of the cleaning blade 41 in the sheet passing width direction is shorter than the length of the intermediate transfer belt 6 in the sheet passing width direction (length in the axial direction), and the maximum sheet passing width of the intermediate transfer belt 6 (the maximum printable image length). Is set to be longer than significantly). Further, the intermediate transfer belt 6 is constituted by a laminated body composed of a plurality of layers, and at least one layer is an elastic layer. The Young's modulus on the surface of the intermediate transfer belt 6 may be 300 to 2000 MPa. Furthermore, the thing of 500-1200 MPa is more preferable.

  The collection screw 42 collects the residue RE scraped off from the intermediate transfer belt 6 by the cleaning blade 41 and conveys it to, for example, a waste toner case (not shown) outside the housing 40. It is pivotally supported by the housing 40 so as to extend. A spiral screw blade is provided on the outer periphery of the recovery screw 42. The recovery screw 42 is rotated by the rotational power of a screw drive motor (not shown), and the residue RE scraped off from the intermediate transfer belt 6 is conveyed outside the housing 40.

  The transfer belt cleaner 12 further includes a cylindrical pressing roller 43 that extends in the sheet passing width direction as a pressing member that presses a portion upstream of the contact portion with the cleaning blade 41 on the surface of the intermediate transfer belt 6. The pressing roller 43 extends in parallel with the driven roller 9. The pressing roller 43 according to the first embodiment is located in the vicinity of the tip of the cleaning blade 41 (the portion facing the intermediate transfer belt 6). Both end portions of the pressing roller 43 in the longitudinal direction of the roller shaft 44 are rotatably supported on the front end side (upper end side) of the hanger rod 45 positioned on the front and rear sides of the cleaning blade 41. The base end side (lower end side) of each hanger rod 45 penetrates the boss body 46 fixed to the front and rear side surfaces of the cleaning blade 41 so as to be slidable. A rise restricting pin 47 is attached to the proximal end portion of the hanger rod 45 (a portion closer to the proximal end than the boss body 46). In the hanger rod 45, a pair of upper and lower seat plates 48 and 49 are fitted on the tip side of the boss body 46 so as to be slidable in the longitudinal direction of the hanger rod 45. A compression spring 50 is fitted in the middle part of the hanger rod 45 so as to be positioned between the upper and lower seat plates 48 and 49. A lowering restriction pin 51 is attached to the front end side of the hanger rod 45 (between the pressing roller 43 and the upper seat plate 48). The compression spring 50 always urges the pressing roller 43 toward the surface of the intermediate transfer belt 6.

  The pressing roller 43 may be made of metal or resin. A metal that is less likely to cause uneven pressure distribution in the sheet-passing width direction is preferable because it can be expected to suppress the formation of a raised portion due to frictional resistance between the cleaning blade 41 and the intermediate transfer belt 6. The pressing roller 43 according to the first embodiment has a cylindrical shape and comes into line contact with the surface of the intermediate transfer belt 6, but may have a polygonal cross section. If the shape is in surface contact with the surface of the intermediate transfer belt 6, it is understood that the effect of suppressing the formation of the raised portion of the intermediate transfer belt 6 is high. If the pressing roller 43 is close to a columnar shape, the surface of the intermediate transfer belt 6 is hardly roughened, and an increase in the friction coefficient of the surface of the intermediate transfer belt 6 can be suppressed.

Since the pressing roller 43 of the first embodiment is pressed and biased toward the surface of the intermediate transfer belt 6 by a pair of compression springs 50, the position of the pressing roller 43 is changed by elastic deformation of both compression springs 50. It is possible to absorb and level the formation of the raised portion of the intermediate transfer belt 6. Of course, the pressing roller 43 may be provided in a fixed position with respect to the cleaning blade 41.

  The pressing roller 43 of the first embodiment is attached to the cleaning blade 41 via a pair of hanger rods 45 (the cleaning blade 41 supports the pressing roller 43). For this reason, even if the arrangement of the cleaning blade 41 with respect to the intermediate transfer belt 6 varies slightly, the pressing roller 43 is surely located near the tip of the cleaning blade 41 (near the contact portion between the intermediate transfer belt 6 and the cleaning blade 41). Can be located.

  Further, the starting point of the formation of the raised portion due to the frictional resistance between the cleaning blade 41 and the intermediate transfer belt 6 is the contact portion between the intermediate transfer belt 6 and the cleaning blade 41. For this reason, if the pressing roller 43 is positioned in the vicinity of the front end portion of the cleaning blade 41 (near the contact portion between the intermediate transfer belt 6 and the cleaning blade 41), the rising portion immediately after the start of formation is surely secured by the pressing roller 43. Can be suppressed. In particular, as shown in FIG. 2A, when the cleaning blade 41 is arranged in a counter manner, it extends toward the intermediate transfer belt 6 from an end surface of the cleaning blade 41 opposite to the contact portion in a side view. It is desirable to arrange the pressing roller 43 (pressing member) in a region surrounded by the extension line L and the contact portion. By doing so, it is possible to reliably prevent the rising portion from becoming large until it winds around the cleaning blade 41. Furthermore, since the pressing roller 43 has a long shape along the sheet passing width direction, it is possible to minimize the formation of the raised portion on the intermediate transfer belt 6.

  As is apparent from the above description, according to the first embodiment, the presence of the pressing roller 43 that presses the upstream portion of the surface of the intermediate transfer belt 6 with respect to the contact portion with the cleaning blade 41 is caused by the frictional resistance. The formation of the raised portion can be suppressed, and the occurrence of blade turning can be reliably prevented.

(3). Second Embodiment of Transfer Belt Cleaner Next, a second embodiment of the transfer belt cleaner 12 will be described with reference to FIGS. 4 and 5. In the second embodiment, a pressing roller 53 as a pressing member is attached to the rotating shaft of the image carrier (in this case, the rotating shaft 9a of the driven roller 9 around which the intermediate transfer belt 6 is wound). That is, the annular support collar 52 is fitted to both ends of the driven roller 9 in the longitudinal direction of the rotating shaft 9a so as to be relatively rotatable and not displaceable in the longitudinal direction of the rotating shaft 9a. Each support collar 52 is provided with a cylindrical boss body 56 protruding outward. The base end side of the hanger rod 55 is slidably inserted into each boss body 56. The both ends of the roller shaft 54 in the longitudinal direction of the pressing roller 53 are rotatably supported on the front end side (projecting end side) of each hanger rod 55. The pressing roller 53 of the second embodiment is also located in the vicinity of the tip of the cleaning blade 41 as in the first embodiment. The hanger rod 55 and the boss body 56 are provided with locking portions 57 and 58, respectively. A tension spring 60 is stretched over both the locking portions 57 and 58. The tension spring 60 always pulls the hanger rod 55 into the boss body 56 and urges the pressing roller 53 toward the surface of the intermediate transfer belt 6. Other configurations are the same as those of the first embodiment. Also when comprised in this way, the effect similar to 1st Embodiment is acquired. It goes without saying that various aspects (variations) described in the first embodiment can also be adopted in the second embodiment.

(4). Another embodiment of transfer belt cleaner (pressing member) (third to sixth embodiments)
In the first and second embodiments, the pressing rollers 43 and 53 that are long in the sheet passing width direction are employed as the pressing member, but the present invention is not limited to this. For example, the third embodiment shown in FIG. 6 is a modification of the first embodiment. In the third embodiment, one pressing roller 63 is provided for one hanger rod 45, and in the upstream portion of the surface of the intermediate transfer belt 6 with respect to the contact portion with the cleaning blade 41, in the sheet passing width direction. Both ends are configured to be pressed by both pressing rollers 63. Other configurations are the same as those of the first embodiment. Thus, the frictional resistance between the cleaning blade 41 and the intermediate transfer belt 6 can be achieved by pressing at least both ends of the intermediate transfer belt 6 upstream of the contact portion with the cleaning blade 41 in the sheet passing width direction. It is possible to suppress the formation of the raised portion due to the above.

  The fourth embodiment shown in FIG. 7 is a modification of the second embodiment, and is technically similar to the third embodiment. That is, one pressing roller 73 is provided for one hanger rod 55, and both end portions in the sheet passing width direction of both portions of the surface of the intermediate transfer belt 6 upstream of the contact portion with the cleaning blade 41 are disposed. The pressure roller 73 is configured to press. Also in this case, similarly to the third embodiment, it is possible to suppress the formation of the bulge portion due to the frictional resistance between the cleaning blade 41 and the intermediate transfer belt 6.

  The fifth embodiment shown in FIGS. 8 and 9 is a modification of the first embodiment, but has a structure in which the number of parts is further reduced. That is, as the pressing member, a pressing bar 83 having a rectangular cross section and long in the sheet passing width direction is fixed to the tip surface of the cleaning blade 41. The pressing bar 83 and the tip corner of the cleaning blade 41 are in contact with the surface of the intermediate transfer belt 6. The sixth embodiment shown in FIG. 10 is a modification of the fifth embodiment, but is technically based on the third and fourth embodiments. That is, the pressing bar 93 having a rectangular cross section is fixed to at least both ends in the sheet passing width direction on the front end surface of the cleaning blade 41. Even with a very simple configuration as in the fifth and sixth embodiments, it is possible to suppress the formation of a raised portion due to the frictional resistance between the cleaning blade 41 and the intermediate transfer belt 6.

(5). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, a printer has been described as an example of the image forming apparatus. In each embodiment, the cleaning blade 41 is arranged in a counter manner with respect to the image carrier. However, in any embodiment, the cleaning blade 41 is arranged with the cleaning blade standing so as to intersect the rotation direction of the image carrier. The formula can be adopted. If the present invention is applied to a cleaning blade arranged in a wiz manner, the formation of a raised portion in the image carrier can be suppressed, and the residue can be reliably prevented from being left behind. The image carrier is not limited to the intermediate transfer belt 6 but may be a belt type photoreceptor. That is, the present invention can also be applied to a cleaning device for a belt-type photoreceptor. In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

1 Printer (image forming device)
3 Image processing device 6 Intermediate transfer belt 8 Drive roller 9 Driven roller 12 Transfer belt cleaner 41 Cleaning blade 42 Recovery screw 43, 53, 63, 73 Press roller (press member)
83, 93 Press bar (press member)

Claims (5)

An image carrier;
A cleaning blade that contacts the downstream side of the transfer position on the image carrier and scrapes the residue on the image carrier;
A pressing member that presses a portion upstream of the contact portion with the cleaning blade on the surface of the image carrier.
Cleaning device.   2. The pressing member according to claim 1, wherein the pressing member is configured to press at least both ends in the sheet passing width direction of a portion of the surface of the image carrier upstream of the contact portion with the cleaning blade. Cleaning device. The pressing member is attached to the cleaning blade,
The cleaning device according to claim 1 or 2. The pressing member is attached to the rotation shaft of the image carrier.
The cleaning device according to claim 1 or 2. The cleaning device according to claim 1 is provided.
Image forming apparatus.

Images