JP2005250047A - Transfer conveyance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer conveyance device in which toner sticking to a transfer conveyance belt is surely removed and cloud toner, which occurs at both ends of a cleaning member, is easily prevented from re-sticking to the transfer conveyance belt. <P>SOLUTION: The transfer conveyance device 1 includes the endless transfer conveyance belt 3 which holds and conveys a recording sheet P for the transfer of a toner image such that the recording sheet P is passed through the transfer position of an image carrier 2 rotating with the toner image T held on it. In the transfer conveyance device 1, the relation of Wc>Ws>Wi and Wb≥Ws are established, wherein Wc is the width of the cleaning member 5 perpendicular to the rotating direction B of the belt, Wb is the width of the transfer conveyance belt 3 perpendicular to the rotating direction B, and Ws is the width of a support member (4A) perpendicular to the rotating direction B of the belt, the support member (4A) being one of the support members 4 for the transfer conveyance belt 3 and disposed opposite the cleaning member 5 with the transfer conveyance belt 3 between them, and Wi is the width of the image holding effective area perpendicular to the rotating direction A of the image carrier 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transfer / conveying device applicable to an image forming apparatus such as a printer, a copying machine, a facsimile, or the like that requires an operation for transferring a toner image to a recording sheet at the time of image formation, or a complex machine that combines these functions. In particular, the present invention relates to a transfer conveyance device of a type using a transfer conveyance belt that conveys a recording sheet so as to pass through the transfer position.

  In an image forming apparatus such as a printer or a copying machine that employs an electrophotographic system, an electrostatic recording system, or the like, generally, a toner image (as a developer) formed on an image carrier such as a photoconductor that rotates based on image information. The image is formed by transferring a toner image) directly to a recording sheet or via an image carrier of an intermediate transfer member and fixing. Further, in such an image forming apparatus, as an apparatus for transferring the toner image to the recording sheet, an endless shape that conveys the recording sheet while holding the recording sheet so as to pass through the transfer position of the toner image on the image carrier. 2. Description of the Related Art A transfer transfer device using a transfer transfer belt is known (Patent Documents 1 and 2).

  Such a transfer / conveying device supports a transfer / conveying belt rotatably on a plurality of support rolls, and holds and conveys the recording sheet by the transfer / conveying belt so as to pass a transfer position of a rotating image carrier. Is configured to do. Then, a transfer electric field is formed by applying a transfer bias between the image carrier and a support roll at a position opposite to the image carrier, whereby a recording sheet on which the toner image on the image carrier is conveyed by a transfer conveyance belt It is a mechanism for electrostatic transfer.

  By the way, in this type of transfer / conveying device, fogging phenomenon or inter-image (region between image regions when sequentially formed with respect to the rotation direction of the image carrier) is present on the image carrier. Since unnecessary toner that is present may be transferred and adhered to the surface side of the transfer / conveying belt, a cleaning member for cleaning the surface of the transfer / conveying belt is provided in contact with the belt surface.

  A blade is generally used as the cleaning member (Patent Documents 1 and 2). In addition, the meandering or shifting of the transfer / conveying belt in the transfer / conveying device using a cleaning member such as a blade is suppressed, and the cleaning failure caused by abrasion of the blade tip due to friction with the belt is suppressed. For the purpose, the belt width (W) in the direction orthogonal to the stretching direction of the transfer conveying belt, the effective image area width (I) of the image carrier, and the cleaning means (blade) in the direction orthogonal to the stretching direction of the transfer conveying belt Technical means for setting the width (C) and the width (S) of the support means (roller) in the direction orthogonal to the stretching direction of the transfer / conveying belt to a relationship of “W> S> C ≧ I” are known. (Patent Document 2).

JP-A-2-110586 (FIG. 1 etc.) Japanese Patent No. 3403816 (Claim 1, FIG. 1, FIG. 4, etc.)

  However, in the conventional transfer / conveying device, the toner may adhere to the transfer / conveying belt even though the cleaning / conveying belt is provided on the transfer / conveying belt. However, there is a problem that the back surface of the recording sheet conveyed thereafter (surface on the side in contact with the transfer conveyance belt at the time of conveyance) is transferred and adhered, and the back surface of the sheet becomes dirty. In addition, at the time of double-sided image formation, the image formed on the first surface of the recording sheet is soiled by the toner on the transfer / conveying belt, and the image quality is deteriorated.

  In addition, since there is a situation in which the transfer conveyance belt is cleaned by the cleaning member at a position close to the recording sheet conveyance path, cloud toner generated during the cleaning operation (of the toner scraped by the cleaning member, various The toner that floats as if it fluctuates due to the above-mentioned factors) easily adheres electrostatically to the transfer conveyance belt charged due to the transfer history or the like, or directly attaches to the recording sheet. Such a phenomenon of cloud toner re-adhesion may be caused by a configuration in which the number of supporting members (rollers, etc.) supporting the transfer / conveying belt is reduced, or by reducing the recording sheet holding / conveying distance of the transfer / conveying belt. When trying to adopt a miniaturized configuration, the cleaning position by the cleaning member is closer to the recording sheet conveyance path, and this tends to occur more easily.

  Furthermore, when the relationship of “W> S> C ≧ I” is set as described above, the width (C) of the cleaning member is shorter than the width (W) of the transfer conveyance belt, and the support roller Since the relationship is shorter than the width (S), both ends of the cleaning member are in a state where both ends of the transfer conveyance belt supported by the opposing rolls protruding longer than the cleaning member are present. The cloud toner generated at both ends is easily reattached to both ends of the transfer conveyance belt in a state where it is supported by the opposing roller, and the toner adhering to the end of the belt causes the end of the recording sheet The side (as viewed from the conveying direction) is likely to become dirty.

  The present invention has been made in view of the above circumstances, and can reliably clean and remove the toner adhering to the transfer / conveying belt, and can also transfer and convey cloud toner generated at both ends of the cleaning member. It is an object of the present invention to provide a transfer / conveying device that can easily suppress reattachment to a belt.

  The transfer conveyance device of the present invention capable of solving the above-described problems is for transferring a toner image to a transfer position of an image carrier 2 that carries and rotates a toner image T as illustrated in FIGS. An endless transfer / conveying belt 3 that holds and conveys the recording sheet P, a plurality of support members 4A and 4B that rotatably support the transfer / conveying belt 3, and a plurality of supports And a cleaning member 5 that contacts and cleans the belt surface in a direction orthogonal to the belt rotation direction B within the region of the transfer conveyance belt 3 supported by any one of the members 4 (4A). The transfer conveying device 1 includes a width (Wc) in a direction perpendicular to the belt rotation direction B of the cleaning member 5, a width (Wb) in a direction perpendicular to the rotation direction B of the transfer conveyance belt 3, and the support member. 4 of the cleaning member 5 The width (Ws) of the support member (4A) opposed across the copying / conveying belt 3 in the direction perpendicular to the belt rotation direction B, and the width of the image carrying effective region in the direction perpendicular to the rotation direction A of the image carrier 2 (Wi) is set to have a relationship of Wc> Ws> Wi and Wb ≧ Ws.

  Here, the image carrier 2 may be any material as long as it can carry the toner image T and rotate it to the transfer position (TN). As such an image carrier 2, for example, a photoconductor that also forms the toner image T itself, or the toner image T is formed by another component (such as a photoconductor). An intermediate transfer member or the like that temporarily receives and conveys a toner image formed by the other components by transfer is used. Further, the image carrier 2 may be a drum shape in addition to the belt shape. As the toner image T forming means, a known image forming means utilizing an electrophotographic method, an electrostatic recording method or the like can be applied. The recording sheet P may be any sheet as long as it can transfer the toner image using the transfer / conveyance device 1, and the material, thickness, form, size, and the like are not particularly limited.

  The transfer conveyance belt 3 may be any belt that can hold at least the entire width of the recording sheet P in the feeding direction. As such a transfer / conveying belt 3, for example, a surface layer formed on a base material made of a rubber material or the like and adjusted so that the entire resistance value (volume resistivity) falls within a predetermined range is used. The

  The plurality of support members 4 are usually rotating rolls, but may be ones in which a part of the plurality of support members 4 is fixedly installed (cylindrical or plate-like ones). The number of support members 4 is not particularly limited, but two is preferable from the viewpoint of reducing the size of the apparatus. Also, one of the plurality of support members 4 may be used as a transfer member so as to form a transfer nip portion by pressing the transfer conveyance belt 3 against the transfer position of the image carrier 2. In this case, the support member 4 also serving as the transfer member is placed in a state in which the toner is easily adsorbed by static electricity due to the transfer electric field formed at the time of transfer. As described above, the width Wc of the cleaning member 5 is the support member 4. The width Wb of the transfer / conveying belt 3 is set to be wider than the width Ws of the support member 4, so that the cleaning member 5 is supported by the support member 4 and protrudes out at both ends. An end region of a certain belt 3 does not exist. For example, compared to the case where the width of the cleaning member 5 is set to be narrower than the width of the support member, the crut toner is present at the end portion of the belt 3. There is an advantage that there is little or no adhesion.

  The cleaning member 5 may be any member that can contact the transfer conveyance belt 3 (the outer peripheral surface thereof) and remove foreign matters such as toner adhering to the belt. A plurality of cleaning members 5 can be installed in the rotation direction of the transfer conveyance belt 3. Further, the cleaning member 5 may be provided with an auxiliary member for removing the toner or the like removed by the cleaning member 5 as necessary. As such a cleaning member 5, a blade can be generally used. However, due to the setting relationship of the respective widths, turning at the end of the cleaning member protruding from the end of the opposing support member 4 (A). From the viewpoint of preventing the occurrence of poor cleaning due to the phenomenon and the meandering of the transfer / conveyance belt, it is preferable to use a brush body that makes the bristles contact the transfer / conveyance belt. The brush body may be a fixed type, but is preferably a rotary type.

  About the setting regarding each said width | variety Wc, Wb, Ws, Wi, especially the width Wc of the cleaning member 5 is set to a value about 1.01 times-1.1 times larger than the width Ws of the supporting member 4 (A) which opposes. Good. In the case where a plurality of cleaning members 5 are installed, each of the cleaning members is set to a size that satisfies the above relationship in width (Wc).

  The widths Wc, Wb, Ws, and Wi may be set so as to further satisfy the relationship of Wb ≧ Wc> Ws> Wi. The reason why such a setting is preferable is as follows.

  First, in the basic setting relationship (Wc> Ws> Wi and Wb ≧ Ws), the width Wb of the transfer conveyance belt 3 may be smaller than the width Wc of the cleaning member 5 (Wc> Wb). Will be included. In other words, as illustrated in FIG. 2, both end portions 3a and 3b in the width direction of the transfer / conveying belt 3 are within the difference region (α, β) between the width Wc of the cleaning member 5 and the width Ws of the support member. May be a relationship. In this case, there is a possibility that cloud toner generated at both ends of the cleaning member 5 protruding from the (both) ends of the transfer conveyance belt 3 may reattach to both ends of the belt 3, and the generation of the cloud toner itself. In order to prevent this, for example, it is necessary to fix and install a brush body or the like that reaches both ends of the transfer conveyance belt 3 at both ends of the cleaning member 5 as a sealing material.

  However, when the fixed side seal material is installed, it may hinder the rotation operation of the transfer / conveyance belt 3, and the manufacturing tolerance of the thickness of the belt 3 and the opposing support member 4 (A). The transfer conveyance belt 3 may be likely to meander due to the pressure at the transfer nip portion being different at both ends in the belt width direction due to manufacturing tolerances, mounting tolerances, and the like. In particular, as the peripheral length of the transfer / conveying belt is shortened to make the entire transfer / conveying device smaller, meandering of the transfer belt tends to occur more easily.

  In this respect, when the width Wb of the transfer conveyance belt 3 is set to be larger than the width Wc of the cleaning member 5 (Wb ≧ Wc), that is, as illustrated in FIG. When the both end portions 3c and 3d of the knives have such a dimensional relationship as to protrude from the end portion of the cleaning member 5 in the width Wc direction, such a problem is avoided. That is, the cloud toner hardly adheres to both ends of the transfer / conveyance belt 3 as described above without the installation of the fixed type side seal material. Such a hindrance to the rotation operation of the transfer conveyance belt 3 and the occurrence of meandering can be avoided.

  According to the transfer / conveying apparatus 1 of the present invention, since the width (Wc) of the cleaning member is set to be greater than the width (Ws) of the opposing support member, the width (Ws) of the support member is greater. Of the transfer conveyance belt having the width (Wb), at least the belt region supported by the support member is reliably cleaned. Even if cloud toner is generated at both ends of the cleaning member during cleaning, both ends of the transfer / conveyance belt do not exist as if they protrude, or even if they exist, the belt end is supported by the support member. The cloud toner is transferred because it exists in a state separated from the cleaning member (bent to the inner peripheral surface because it is stretched and supported by the support member). Reattachment to both ends of the transport belt and the end of the recording sheet is almost eliminated. Thereby, it is possible to sufficiently prevent the back surface of the recording sheet conveyed by the transfer conveyance belt from being stained with toner.

  FIG. 3 is a schematic explanatory view showing the main part of the image forming apparatus to which the transfer conveying apparatus according to the first embodiment of the present invention is applied. FIG. 4 is a schematic explanatory view showing the transfer conveying apparatus in FIG. It is.

  The image forming apparatus 100 forms a toner image corresponding to predetermined image information in the image forming unit 120 and then supports the toner image on a plurality of support rolls 131 to 133 to rotate in an arrow direction A. The primary transfer is performed to 130, and is conveyed to a secondary transfer position facing the transfer conveyance device 10. On the other hand, the recording sheet in which the toner image is supplied at a predetermined timing from the sheet storage unit 140 between the intermediate transfer belt 130 and the transfer conveyance device 10 by a plurality of conveyance rolls 141 to 143 and the like in accordance with the image formation timing. Secondary transfer to P. Thereafter, the recording sheet P to which the toner image has been transferred is sent to the fixing device 160 by the conveying device 150 and the like, and the toner image is fixed to the recording sheet P, and then discharged outside the device. An image is formed. A one-dot chain line with an arrow in the figure indicates a conveyance path of the recording sheet P.

  Among these, the image forming unit 120 can form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K). In the first embodiment, the four photosensitive drums 121 are arranged in series at regular intervals along the rotation direction A of the intermediate transfer belt 130 so as to be rotatable, and a charging device (not shown) is provided around each photosensitive drum 121. , An exposure device and a developing device (accommodating any one of the four colors Y, M, C, and K toners and performing development with the toner of that color) are arranged in this order. The so-called tandem type color image forming unit is employed.

  In the tandem type color image forming unit 120, the above four colors (Y, M, C, K) are formed on each photosensitive drum 121 by executing the electrophotographic process of charging, exposure and development on each photosensitive drum 121. ) Toner image is distributed and formed. The toner images are electrostatically superimposed on the outer peripheral surface of the rotating intermediate transfer belt 130 by an electrostatic transfer device installed with the photosensitive drums 121 and the intermediate transfer belt 130 interposed therebetween. I try to make it transfer. The outer peripheral surface of each photosensitive drum 121 after the transfer is cleaned by a cleaning device (not shown).

As the intermediate transfer belt 130, a synthetic resin such as polyimide or polyamide and a conductive agent such as carbon black is applied and formed into an endless belt shape having a belt width of about 365 mm and a thickness of about 0.1 mm. (Volume resistivity: about 10 ¹⁰ to 10 ¹⁴ Ω · cm) is used. The intermediate transfer belt 130 is rotated in the arrow A direction at a predetermined speed by a support roll 131 that also serves as a drive roll. The support roll 133 is also used as a backup roll at the secondary transfer position, and a secondary transfer bias having the same polarity as the toner charging polarity is applied from a bias power source (not shown) via the power supply member 134 and the like. Yes. Further, the surface of the intermediate transfer belt 130 after the secondary transfer is cleaned by the cleaning device 138.

  The transfer conveyance device 10 holds and conveys the recording sheet P by the transfer conveyance belt 30 so as to pass through the secondary transfer position.

  In the first embodiment, the transfer conveying belt 30 is installed at a secondary transfer position so as to come into contact with the intermediate transfer belt 130 that is in contact with the backup roll 133, and the fixing device includes the first support roll 41. It is used that is stretched and supported rotatably on a second support roll 42 installed in parallel with a predetermined interval on the 150 side.

The transfer conveyance belt 30 is a surface layer in which a conductive material such as conductive carbon black is dispersed in a rubber material such as chloroprene or EPDM, and the surface of the substrate is coated with a PTFE-dispersed urethane emulsion or the like. Is an endless belt having a thickness of about 0.5 mm and a volume resistivity of about 10 ⁶ to 10 ¹² Ω · cm. The 1st support roll 41 consists of an electroconductive roll, and while being rotatably supported, it is earth | grounded. The second support roll 42 is made of a conductive roll and is rotatably supported. In order to reduce the size of the transfer / conveyance apparatus 10 in particular, a belt having an inner diameter of about 40 mm is used as the transfer / conveyance belt 30, a metal roll having a roll diameter of about 28 mm is used as the first support roll 41, and a second support roll. As 42, a metal roll having a roll diameter of about 15 mm is used. Further, the transfer / conveying belt 30 is stretched so as to have an extension ratio of about 2.2%, and is driven to rotate in the direction of arrow B with the first support roll 41 as a driving roll.

  In such a transfer conveyance device 10, the recording sheet P is supported by the backup roll 133 and supported by the intermediate transfer belt 130 rotating in the arrow A direction and the first support roll 41, and the transfer conveyance rotating in the arrow B direction. The belt is introduced into the belt TN (secondary transfer nip portion) TN and conveyed while being held by the transfer conveyance belt 30 so as to pass through the transfer position TN. At this time, since a transfer electric field is formed between the secondary transfer bias applied to the backup roll 133 and the first support roll 41, the toner image T on the intermediate transfer belt 130 is electrostatically transferred to the recording sheet P. Is transcribed. Then, the recording sheet P on which the toner image T has been transferred is peeled off from the transfer conveyance belt 30 portion which is bent and travels abruptly on the second support roll 42, and is sent to the conveyance device 150 side on the downstream side in the traveling direction. It is done.

  Further, the transfer / conveyance device 10 is provided with a cleaning device 50 for cleaning the outer peripheral surface of the transfer / conveyance belt 30. The cleaning device 50 includes a brush roll 51 that rotates in contact with an area supported by the first support roll 41 of the transfer conveyance belt, and a collection for collecting toner and the like adhering to the brush bristles of the brush roll 51. The roller 55 includes a scraper 56 that removes the toner image collected on the outer peripheral surface of the collecting roller 55, and a waste toner storage unit 59 that also serves as a housing of the cleaning device 50.

  The brush roll 51 includes a roll shaft (shaft) 52 made of a metal such as aluminum or stainless steel, and brush hairs 53 that are provided radially on the surface of the roll shaft 52. The brush bristles 53 are fixed so as to be woven at a predetermined density on one side of the belt-like cloth material. It was raised in a radial manner. As the bristle 53, synthetic fibers made of nylon, polypropylene, rayon, acrylic, or the like can be used. Further, the brush hair 53 may be provided with conductivity by adding a conductive agent such as carbon black to the synthetic fiber. The brush roll 51 is supported so that the tip of the bristles 53 can be rotated in a state in which the tip of the brush bristles has bitten into the transfer and conveyance belt 30, and the rotational power of the first support roll 41 is rotated. By being transmitted through the transmission mechanism, it is rotationally driven in an arrow direction shown in FIG. 2 (a direction opposite to the rotation direction B of the transfer conveyance belt 30 at the contact portion).

  Further, the collection roll 55 is made of a synthetic resin roll such as a phenol resin imparted with conductivity, and is rotatably supported so as to be in contact with the brush bristles 53 of the brush roll 51. Similarly to the case of the brush roll 51, this collection roll 55 is also transmitted in the direction of the arrow shown in FIG. 2 by transmitting the rotational power of the first support roll 41 via the rotation transmission mechanism (the brush roll 51 is at its contact portion). It is driven to rotate in the opposite direction. As the scraper 56, a plate material made of stainless steel or the like is pressed against the outer peripheral surface of the recovery roll 55 at a predetermined angle.

  Further, a predetermined bias was applied to the brush roll 51 and the collection roll 55 from a bias power source (not shown). As a result, the toner and the like can be attracted and removed by electrostatic action.

  In the cleaning device 50 in the transfer conveyance device 10, the width (Wb) in the direction orthogonal to the rotation direction B of the transfer conveyance belt 30, the width (Wc) in the direction orthogonal to the belt rotation direction B of the brush roll 51, brush The width (Ws) of the first support roll 41 installed at a position facing the roll 51 in the direction orthogonal to the belt rotation direction B, and the width of the image carrying effective area in the direction orthogonal to the rotation direction A of the intermediate transfer belt 130 (Wi) is set so that the relationship of Wb ≧ Wc> Ws> Wi is established.

  Specifically, the width Wb of the transfer conveyance belt 30 is 345 mm, the width of the brush roll 51 (strictly, the length between the ends of the brush bristles 53) Wc is 339 mm, the width Ws of the first support roll 41 is 332 mm, The width Wi of the image carrying effective area of the intermediate transfer belt 130 was 317 mm. As for the brush roll 51, brush hair 53 made of 2-denier conductive nylon is radially raised on a roll shaft 52 having a roll diameter of 6 mm at a density of 12,000 pieces / square inch and a height of 5.5 mm. A sample (brush outer diameter: 17 mm) was used and installed in a state where the amount of biting was 1.5 mm.

  Further, in the cleaning device 50, when the width of the opening (the length in the axial direction of the brush roll 51) facing the transfer conveyance belt 30 of the waste toner reservoir 59 is Wt, the opening of the waste toner reservoir 59 The width Wt is set to have a relationship of Wt ≧ Wc, preferably a relationship of Wt = Wc. Cloud toner is generated inside the waste toner storage portion 59, and a part of the cloud toner is a gap between a portion of the brush roll 51 without the brush hair 53 (exposed portion of the shaft 52) and the inner wall of the opening portion of the waste toner storage portion 59. The leakage may occur from (Wt−Wc). For this reason, it is desirable to reduce the gap portion from the viewpoint of suppressing the occurrence of such a cloud toner and thus preventing the toner from adhering to the end of the transfer / conveying belt 30, and the opening portion of the waste toner storage portion 59. The width Wt is preferably as close to the width Wc of the brush roll 51 as possible. Therefore, also in this embodiment, the value of Wt−Wc is set to fall within the range of 10 mm.

  In the transfer / conveyance device 10, by providing such a cleaning device 50, even if unnecessary toner adhering to the intermediate transfer belt 130 is transferred to the transfer / conveyance belt 30 during the secondary transfer or the like, it is applied. When the toner passes through the rotating brush roll 51 in the cleaning device 50, the toner is captured and removed by the brush bristles 53. The toner removed by the brush roll 51 is electrostatically attracted and collected by a collection roll 55 that rotates in contact with the brush roll 51, and then scraped off by a scraper 56. Finally, waste toner is stored. Part 59 is accommodated.

  Further, in this cleaning device 50, since the width Wc of the brush roll 51 is set to be larger than the width Ws of the first support roll 41, the width (Wb) equal to or greater than the width Ws of the first support roll 41. At least the belt region supported by the first support roll 41 in the transfer conveyance belt 30 having the above is reliably cleaned. In addition, even if cloud toner (including toner generated by rising from the inside of the collected toner storage unit 59) is generated at both ends of the brush roll 51, the transfer conveyance belt 30 is stretched between the two support rolls 41 and 42. As shown in FIG. 6, the belt end region 30a that protrudes from the end of each of the support rolls 41 and 42 is bent so as to hang down to the inner peripheral surface side of the belt because it is not supported by the support roll. Therefore, the cloud toner hardly adheres to the end portions of the recording sheet P as well as the both end regions 30a of the transfer / conveyance belt 30. As a result, the back surface of the recording sheet P conveyed by the transfer conveyance belt 30 and its end are hardly contaminated with toner.

  In the first embodiment, the case where the recovery roll 55 and the auxiliary member of the scraper 56 are installed with respect to the brush roll 51 of the cleaning device 50 in the transfer conveyance device 10 is illustrated. Instead of the auxiliary member, as shown in FIG. 7, a configuration may be applied in which a flip cover 57 for contacting the brush bristles 53 and shaking off the toner adhering to the bristles 53 is fixedly installed as an auxiliary member.

  In this case, the flip cover 57 may be made of an insulating or conductive plate member or the like. When a conductive material is used, it is grounded or a predetermined bias is applied. In the cleaning device 50 </ b> B provided with the flip cover 57, the toner that is removed from the transfer conveyance belt 30 by the rotating brush roll 51 and adheres to the brush bristle 53 is shaken off by the flip cover 57 that contacts the moving brush bristle 53. After that, the toner is collected in the toner collecting unit 59.

  Further, in the first embodiment, if necessary, the cleaning device 50 for the transfer conveyance belt 30 is not limited to the case where the cleaning device 50 is installed in the area of the transfer conveyance belt 30 supported by the first support roll 41. As indicated by a two-dot chain line, the cleaning device 50C can be installed in the region of the transfer conveyance belt 30 supported by the second support roll 42 instead of or in combination with the region. .

  Further, in the transfer conveyance device 10 of the first embodiment, as shown in FIG. 8, the width Wb of the transfer conveyance belt 30 is not less than the width Ws of the first support roll 41 and smaller than the width Wc of the brush roll 51. May be set.

  In this case, as shown in FIG. 8, the end of the brush roll 51 (actually the end 53a of the brush bristles 53) is long from the end of the first support roll 41 together with the end 30a of the transfer conveyance belt 30. It will be in the state protruded by e. However, when the brush roll 51 is used, at the end 51a where the first support roll 41 and the transfer / conveying belt 30 are not present, the end region 53a of the brush bristles 53 is opened as much as the biting amount disappears. Therefore, the state of the bristles 52 in the region where the first support roll 41 and the transfer conveyance belt 30 exist is not affected. As a result, in the transfer conveyance belt 30 region where the first support roll 41 is present, the brush roll 51 is satisfactorily exhibited as in the case of the first embodiment. Further, the end region 30a of the transfer conveyance belt 30 where the first support roll 41 does not exist is also covered with the brush bristles 53, so that the toner in the end region 30a can be removed and cloud toner can be removed. Reattachment can be effectively prevented.

  In the first embodiment, the tandem type color image forming unit is illustrated as the image forming unit 120 in the image forming apparatus 100. However, as the image forming unit 120, other types shown below are applied. Is also possible.

  For example, a 4-cycle type color image forming unit may be applied. The four-cycle type color image forming unit 120 uses a single photosensitive drum 121, a charging device, an exposure device, and the four colors (Y, M, C, K) around the photosensitive drum 121. A rotary type developing device in which four developing units each containing toner are arranged at equal intervals along the peripheral surface of the rotary support are sequentially installed, and then the four colors of the four colors are rotated while the photosensitive drum 121 is rotated four times. Toner images are sequentially formed. In this case, each toner image formed on the photosensitive drum 121 is sequentially primary-transferred and superimposed on the intermediate transfer belt 130 for each rotation.

  In addition, the image forming unit 120 of a single color type that forms one single color (particularly black) toner image is not limited to the one that forms a color toner image. In this case, normally, the single-color toner image is formed on one photosensitive drum, while the intermediate transfer system using the intermediate transfer belt 130 is not adopted, and the transfer conveying device 10 (specifically, the transfer position of the photosensitive drum). Specifically, the transfer conveyance belt 30) is directly installed.

It is explanatory drawing which shows the outline | summary of the transfer conveyance apparatus of this invention. It is explanatory drawing which shows the dimensional relationship between the specific components in the apparatus of FIG. FIG. 2 is a schematic explanatory diagram illustrating a main part of an image forming apparatus to which the transfer conveyance device according to the first embodiment is applied. FIG. 2 is an explanatory view showing, in an enlarged manner, a transfer conveyance device according to Embodiment 1 and its peripheral portion. It is explanatory drawing which shows the dimensional relationship between the specific components in the apparatus of FIG. It is explanatory drawing which expands and shows the state of the edge part of a transfer conveyance belt, and its peripheral part. It is explanatory drawing which shows other embodiment of a transfer conveyance apparatus (mainly the cleaning apparatus). It is explanatory drawing which shows the principal part of other embodiment of the cleaning apparatus in a transfer conveyance apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10 ... Transfer conveyance apparatus, 2 ... Image carrier, 3,30 ... Transfer conveyance belt, 4 ... Support member, 5 ... Cleaning member, 41A ... First support roll (support member), 41B ... Second support roll ( Support member), 50, 50b, 50C ... cleaning device, 51 ... brush roll (cleaning member, brush body), 121 ... photosensitive drum (image carrier), 130 ... intermediate transfer belt (image carrier), P ... recording sheet , T: toner image, A: rotation direction of intermediate transfer belt (image carrier), B: rotation direction of photosensitive drum (image carrier), TN: transfer position.

Claims (3)

An endless transfer conveyance belt that holds and conveys a recording sheet for transferring the toner image to a transfer position of an image carrier that carries and rotates the toner image; and
A plurality of support members for rotatably supporting the transfer conveyance belt;
A transfer conveyance provided with a cleaning member that contacts and cleans the belt surface in a region perpendicular to the belt rotation direction within the area of the transfer conveyance belt supported by any of the plurality of support members A device,
The width (Wc) of the cleaning member in the direction orthogonal to the belt rotation direction, the width (Wb) in the direction orthogonal to the rotation direction of the transfer / conveyance belt, and the support member facing the cleaning member and the transfer / conveyance belt. The width (Ws) of the support member in the direction perpendicular to the belt rotation direction, and the width (Wi) of the image carrying effective region in the direction perpendicular to the rotation direction of the image carrier,
Wc>Ws> Wi and Wb ≧ Ws
A transfer conveyance device characterized by being set in a relationship with   The transfer conveyance device according to claim 1, wherein the widths Wc, Wb, Ws, and Wi are set in a relationship of Wb ≧ Wc> Ws> Wi.   The transfer / conveying apparatus according to claim 1, wherein the cleaning member is a brush body that makes the brush hair contact the transfer / conveying belt.

Images