JP2006219207A - Paper guide device of image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper guide device, removing toner adhering to be deposited on the surface of a guide rib for guiding paper by simple constitution, thereby restraining the occurrence of an image defect such as a linear scratch. <P>SOLUTION: A paper guide device 30 on the downstream side in the paper carrying direction of a fixing part 20 switches the carrying direction of paper P to sort the paper to two paper carrying passages on the downstream. Sorting of the paper P is performed by a rotatable movable guide 31 provided with a plurality of guide ribs 33 for guiding the paper. An outer carrying guide 42, which is a fixed guide of a paper carrying passage 40 for delivery, is provided with upper rib cleaning members 35 corresponding to the respective guide ribs 33 of the movable guide 31. In the process of switching the attitude of the movable guide 31 for sending the paper to the paper P carrying passage 40 for delivery to the attitude for sending the paper P to a paper carrying passage for reversing, the downstream part 33b, which is a paper contact part of the upper surface of the guide rib 33, is caused to rub the upper rib cleaning member 35 to clear away adhering toner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet guide device for an image forming apparatus represented by a copying machine or a printer.

  In an image forming apparatus such as a copying machine or a printer, elements such as a paper feed unit, a transfer unit, a fixing unit, a double-sided printing paper reversing unit, and a discharge unit are arranged, and a paper conveyance path is formed between them. ing. The paper transport path includes a guide member that configures the transport path, guide ribs that directly contact the paper and guide the paper, a transport roller that feeds the paper, and the like.

In the paper transport path, the paper is frequently transported, so that the paper comes into contact with the guide member, the guide rib, and the transport roller, and these members are contaminated with toner or paper dust adheres. Has occurred. Various countermeasures have been proposed in the past for the problem of the contamination of the paper conveyance path. Of these, one example relating to preventing the accumulation of paper dust on the conveyance path is shown in Patent Document 1. Can do. In the sheet conveying apparatus described in Patent Document 1, an opening and an opening / closing mechanism thereof are provided in a sheet guide (guide member), and before the paper dust accumulates on the sheet guide, the paper dust is placed outside the sheet guide by the opening / closing mechanism. I try to drop it.
Japanese Patent Laying-Open No. 2004-161482 (page 4-9, FIG. 3)

  Here, as a member that is easily soiled by toner or paper dust adhering to the paper, a guide rib can be cited in addition to the guide member. The guide ribs of the paper transport path are normally formed in a flat plate shape extending in the paper transport direction, and are attached so as to be substantially perpendicular to the guide members constituting the transport path. As a result, the guide rib guides the sheet by contacting the end thereof substantially perpendicular to the sheet surface of the sheet on the conveyance path. Therefore, the guide ribs are in direct contact with the paper, and are particularly easily contaminated with toner. Further, since the toner is easily fused between the toners, there is a possibility that the toner gradually accumulates on the surface of the guide rib due to contact with the paper and grows into an acute nail shape. As a result, there is a high possibility that image defects will occur due to, for example, leaving linear scratches on the paper surface.

  Moreover, in the sheet conveying apparatus described in Patent Document 1, a method for treating paper dust that has fallen on the surface of a sheet guide (guide member) has been proposed. On the other hand, the guide ribs are in direct contact with the paper, and the toner deposited on the surface tends to adversely affect the paper as described above. Therefore, it is more desirable to take the first countermeasure against the contamination on the surface of the guide rib with respect to the paper conveyance path.

  The present invention has been made in view of the above points, and with respect to the guide rib for guiding the paper on the paper conveyance path, the toner adhering to and accumulating on the surface thereof is removed with a simple configuration, and image defects such as linear scratches are removed. An object of the present invention is to provide a sheet guide device for an image forming apparatus that can suppress the occurrence of the above.

  In order to solve the above-mentioned problems, the present invention comprises a guide that is provided with guide ribs for guiding a sheet, the angle of which can be changed to distribute the sheet to two sheet conveyance paths, and the sheet conveyance path. It is provided with a rib cleaning member that is provided at a location corresponding to the guide rib of the movable guide of the fixed guide, and that contacts the paper contact location of the guide rib as the angle of the movable guide changes.

  Further, the rib cleaning member is in contact with the downstream portion of the guide rib in the sheet conveyance direction at the sheet contact portion.

  The rib cleaning member is made of a member having a predetermined elasticity.

  According to the configuration of the present invention, the guide rib for guiding the paper is provided, and the movable guide that can change the angle for distributing the paper to the two paper transport paths and the fixed guide that constitutes the paper transport path are movable. It is provided at a location corresponding to the guide rib of the guide, and it is provided with a rib cleaning member that contacts the paper contact location of the guide rib as well as changing the angle of the movable guide, so that the movable guide and the periphery of the guide rib have a complicated configuration Without this, the surface of the guide rib can be automatically cleaned by changing the angle of the movable guide in the normal sheet conveyance process. Therefore, it is possible to remove the toner adhering to and accumulating on the surface of the guide rib with a simple configuration and to suppress the occurrence of image defects such as linear scratches.

  In addition, since the rib cleaning member is in contact with the downstream portion of the guide rib in the paper conveyance direction of the paper contact portion, the paper is transported on the surface of the guide rib where the toner easily adheres when the paper continuously rubs the surface of the guide rib. A direction downstream part can be cleaned with a rib cleaning member. Therefore, it is possible to prevent the toner from being deposited so as to overlap and grow into an acute nail shape at a location where such toner is likely to adhere.

  Further, since the rib cleaning member is made of a member having a predetermined elasticity, even if the toner adheres to the surface of the guide rib and becomes hardened, it can be easily removed. . Further, even if the rib cleaning member directly contacts the guide rib, it is possible to prevent the guide rib from being damaged.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, a tandem color printer will be described as an example of the image forming apparatus.

  First, an image output operation of a printer, which is an image forming apparatus provided with the paper guide device of the present invention, will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of a printer.

  As shown in FIG. 1, a paper cassette 3 is disposed below the inside of the main body 2 of the image forming apparatus 1. Inside the paper cassette 3, paper P such as cut paper before printing is stacked and accommodated. Then, the sheets P are separated and sent one by one toward the upper right of the sheet cassette 3 in FIG. The paper cassette 3 can be pulled out horizontally from the front side of the main body 2.

  On the downstream side of the paper cassette 3 in the paper conveyance direction, a paper feeding paper conveyance path 4 is provided. The paper P sent out from the paper cassette 3 is transported vertically upward along the right side surface of the main body 2 by the paper feed paper transport path 4 and reaches the registration roller 5.

  On the other hand, a sheet conveying belt 6 configured in an endless belt shape is provided in a substantially central portion of the image forming apparatus 1. The paper transport belt 6 is wound around and supported by a plurality of rollers, and is rotated counterclockwise in FIG. 1 by a driving means (not shown).

  Four image forming units 7 are provided above the sheet conveying belt 6. The four image forming units 7 are arranged in series from the upstream side to the downstream side in the rotation direction of the paper transport belt 6. The four image forming units 7 are, in order from the upstream side, a magenta image forming unit 7M, a cyan image forming unit 7C, a yellow image forming unit 7Y, and a black image forming unit 7B. To supplement the image forming units 7 with toner, toner supply containers 8M, 8C, 8Y, and 8B corresponding to the image forming units 7M, 7C, 7Y, and 7B are provided above the image forming units 7 and are not shown. The toner is replenished by the means. Each image forming unit 7 creates an electrostatic latent image of the original image based on the original image data from the external computer, and forms a toner image from the electrostatic latent image.

  The paper P that has reached the registration roller 5 is sent out onto the paper transport belt 6 in synchronism with each image forming section 7. Then, as the paper transport belt 6 rotates, the toner images of the image forming units 7 are sequentially transferred onto the paper P on the belt at a predetermined timing. As a result, a color toner image is formed on the surface of the paper P by superimposing four color toner images of magenta, cyan, yellow, and black.

  A fixing unit 20 is provided on the downstream side of the sheet conveying belt 6. The paper P carrying the unfixed toner image on the paper transport belt 6 is sent to the fixing unit 20, and the toner image is heated and pressed by the fixing roller and the pressure roller to be fixed.

  A paper guide device 30 is provided on the downstream side of the fixing unit 20. The sheet guiding device 30 switches the conveying direction of the sheet P, whereby the sheet P is transferred to the discharge sheet conveying path 40 provided above the sheet guiding apparatus 30 and the reversing sheet conveying path 50 provided below. Distribute. When duplex printing is not performed, the paper P discharged from the fixing unit 20 is switched in the transport direction toward the discharge paper transport path 40 by the paper guide device 30, and the paper discharge tray provided on the upper surface of the main body 2. 9 is discharged.

  When performing duplex printing, the paper guiding device 30 switches the transport direction of the paper P downward. A paper reversing unit 60 for double-sided printing is provided at the tip of the reversing paper transport path 50 below the paper guiding device 30. The paper P that has entered the reversing paper transport path 50 enters the intermediate tray 61 provided in the double-sided printing paper reversing unit 60 from the left to the right in FIG. 1 and is temporarily stored. Then, the transport direction of the paper P is switched to the left, passes through the double-sided printing paper transport path 62, joins the paper feed paper transport path 4, and is sent to the registration roller 5 again.

  Next, a detailed configuration of the sheet guiding apparatus 30 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a partially enlarged schematic vertical section showing the periphery of the sheet guide device and the fixing unit. A solid line arrow in the figure indicates a sheet conveyance path.

  As shown in FIG. 2, the fixing unit 20 includes a fixing roller 21 and a pressure roller 22. The fixing roller 21 is rotated by a motor (not shown) so that the peripheral speed thereof is the same as the paper conveyance speed. Inside the fixing roller 21, a halogen heater 23 as a heat source is disposed. The pressure roller 22 is pressed against the fixing roller 21 to form a nip through which the paper P is inserted. The pressure roller 22 is rotated in accordance with the rotation of the fixing roller 21 by being in pressure contact with the fixing roller 21. A fixing downstream transport roller 24 is provided immediately downstream of the fixing roller 21 and the pressure roller 22.

  A sheet guide device 30 is provided on the downstream side of the fixing downstream portion conveyance roller 24. The sheet guide device 30 is provided with a movable guide 31. The movable guide 31 distributes the paper P to the two paper transport paths continuing from the paper guide device 30. On the downstream side of the paper guide device 30, a discharge paper conveyance path 40 that continues to the paper discharge tray 9 and a reversal paper conveyance path 50 that continues to the double-sided printing paper reversing unit 60 are provided. The movable guide 31 is rotatably provided and can be changed in angle by a solenoid or the like (not shown). Details of the movable guide 31 will be described later.

  The discharge paper transport path 40 above the paper guide device 30 is provided with an inner transport guide 41, an outer transport guide 42, and a discharge transport roller 43. The inner conveyance guide 41 and the outer conveyance guide 42 are fixed guides, and are formed so as to protrude outwardly toward the sheet discharge tray 9 existing above in FIG. Therefore, when the sheet P passes through the discharge sheet conveyance path 40, the printing surface of the sheet P fixed by the immediately preceding fixing unit 20 faces the inner conveyance guide 41. The discharge transport roller 43 is for sending the paper P toward the paper discharge tray 9 and is rotated by a driving means (not shown).

  The reversing paper transport path 50 below the paper guiding device 30 is provided with an inner transport guide 51, an outer transport guide 52, and a reversing transport roller 53. The inner conveyance guide 51 and the outer conveyance guide 52 are fixed guides, and are formed so as to protrude outward toward the double-sided printing paper reversing portion 60 existing below in FIG. Therefore, when the sheet P passes through the reversing sheet conveyance path 50, the printing surface of the sheet P fixed by the immediately preceding fixing unit 20 faces the outer conveyance guide 52. The reversing conveyance roller 53 is for feeding the paper P to the double-sided printing paper reversing unit 60, and is rotated by a driving means (not shown).

  Next, a detailed configuration of the movable guide 31 of the paper guide device 30 will be described with reference to FIGS. FIG. 3 is a partial perspective view of the movable guide provided in the paper guide device, and FIG. 4 is an enlarged schematic vertical cross-sectional view of the movable guide, showing a state in which the movable guide is in a posture to feed the paper to the discharge paper conveyance path. FIG. 5 is a schematic vertical cross-sectional enlarged view of the movable guide, and shows a state in which the movable guide is in a posture to feed the sheet to the sheet conveyance path for reversal.

  As shown in FIGS. 3 and 4, the movable guide 31 includes a base portion 32 and a plurality of guide ribs 33. The base portion 32 has substantially the same length as the discharge paper transport path 40 and the reverse paper transport path 50 in the paper width direction perpendicular to the paper transport direction. A shaft portion 34 is provided at both ends of the base portion 32, and the movable guide 31 is supported by the main body 2 so that the angle can be changed by the shaft portion 34. The movable guide 31 is disposed so that the upstream end 33 a of the guide rib 33 faces the fixing downstream conveyance roller 24 of the fixing unit 20. The angle of the movable guide 31 is changed by swinging the upstream end 33a up and down. The entire movable guide 31 is produced by molding with synthetic resin.

  The plurality of guide ribs 33 are arranged on the base portion 32 at a predetermined interval along the paper width direction of the base portion 32. The guide rib 33 has a flat plate shape extending in the paper transport direction, and guides the paper P in contact with the paper surface of the paper on the transport path at a substantially right angle. The periphery of the guide rib 33 where it contacts with the paper P is finished with a curved surface so that the conveyance resistance with the paper P is as small as possible (see FIG. 3). The guide rib 33 has a wedge shape in cross section perpendicular to the paper width direction of the base portion 32 in order to facilitate the sorting of the paper P.

  An upper rib cleaning member 35 is provided at a position corresponding to each guide rib 33 of the movable guide 31 in the outer conveyance guide 42 which is a fixed guide of the discharge paper conveyance path 40. Similarly, a lower rib cleaning member 36 is provided at a position corresponding to each guide rib of the movable guide 31 in the outer conveyance guide 52 which is a fixed guide of the reversing paper conveyance path 50. Each of the rib cleaning members 35 and 36 is made of a polyethylene terephthalate (PET) film having a predetermined elasticity, and a cross-sectional shape perpendicular to the paper width direction is L-shaped.

  The upper rib cleaning member 35 is configured such that when the movable guide 31 changes the angle to send the sheet P to the reversing sheet conveyance path 50, the sheet conveyance direction downstream portion 33b that is the sheet contact portion on the upper surface of the guide rib 33 is It arrange | positions so that one surface may be contacted (refer FIG. 5). That is, in the process of changing the angle of the movable guide 31 from the posture of sending the paper P to the discharge paper transport path 40 (see FIG. 4) to the posture of sending the paper P to the reversing paper transport path 50 (see FIG. 5). The downstream portion 33b of the upper surface of the guide rib 33 comes into contact with the upper rib cleaning member 35 so as to be rubbed.

  Here, in the normal printing operation, when the paper P discharged from the fixing unit 20 is sent to the discharge paper conveyance path 40, the paper surface opposite to the paper surface on which the toner image is fixed by the immediately preceding fixing unit 20, that is, In FIG. 4, the lower paper surface contacts the upper surface of the guide rib 33. Therefore, when using a new paper P that has not been used for printing on both the front and back sides, there is no problem of toner adhesion and accumulation in the paper conveyance direction downstream portion 33b that is the paper contact portion on the upper surface of the guide rib 33. . However, in recent years, resource saving has been promoted, and reuse of paper P on which one side has already been printed and double-sided printing are frequently performed. As a result, the toner on the paper surface opposite to the paper surface on which the toner image is fixed by the fixing unit 20 immediately before the paper guiding device 30, that is, the toner on the lower paper surface in FIG. There is concern about the possibility of adhering to and depositing on the downstream portion 33b of the upper surface of 33. On the other hand, in the sheet guide device 30 of the present invention, the angle of the movable rib 31 can be changed and the downstream portion 33b of the upper surface of the guide rib 33 can be rubbed against the upper rib cleaning member 35 for cleaning.

  On the other hand, when the angle of the lower rib cleaning member 36 is changed to the posture in which the movable guide 31 sends the paper P to the discharge paper transport path 40, the lower rib cleaning member 36 is downstream in the transport direction in the paper transport direction, which is the paper contact location on the lower surface of the guide rib 33 The part 33c is disposed so as to contact the one surface (see FIG. 4). That is, in the process in which the movable guide 31 changes the angle from the posture of sending the paper P to the reversing paper transport path 50 (see FIG. 5) to the posture of sending the paper P to the discharge paper transport path 40 (see FIG. 4). The downstream portion 33c of the lower surface of the guide rib 33 comes into contact with the lower rib cleaning member 36.

  When the paper P discharged from the fixing unit 20 is sent to the reversing paper conveyance path 50, the downstream surface 33c of the lower surface of the guide rib 33 is always the paper surface on which the toner image is fixed by the immediately preceding fixing unit 20, that is, the paper surface. In FIG. 5, the upper paper surface comes into contact. Therefore, if double-sided printing is frequently performed, the toner tends to adhere and accumulate on the downstream portion 33c of the lower surface of the guide rib 33. On the other hand, in the paper guide device 30 according to the present invention, the downstream portion 33c of the lower surface of the guide rib 33 can be rubbed against the lower rib cleaning member 36 and cleaned together with the change of the angle of the movable rib 31.

  In this way, the guide rib 33 for guiding the paper P is provided, and the movable guide 31 capable of changing the angle to distribute the paper P to the two paper transport paths, and the fixed guide constituting the paper transport path. Since the outer conveyance guides 42 and 52 are provided at locations corresponding to the guide ribs 33 of the movable guide 31 and include rib cleaning members 35 and 36 that come into contact with the sheet contact locations of the guide rib 33 as the angle of the movable guide 31 changes. The surface of the guide rib 33 can be automatically cleaned by changing the angle of the movable guide 31 in the normal sheet conveyance process without making the periphery of the movable guide 31 and the guide rib 33 complicated. Therefore, it is possible to remove the toner adhering to and accumulating on the surface of the guide rib 33 with a simple configuration and to suppress the occurrence of image defects such as linear scratches.

  Further, since the rib cleaning members 35 and 36 are in contact with the paper conveyance direction downstream portions 33b and 33c of the paper contact portion of the guide rib 33, the toner easily adheres when the paper P continuously rubs the surface of the guide rib 33. The downstream portions 33b and 33c in the sheet conveyance direction on the surface of the guide rib 33 can be cleaned by the rib cleaning members 35 and 36. Therefore, it is possible to prevent the toner from being deposited so as to overlap and grow into an acute nail shape at a location where such toner is likely to adhere.

  Since the rib cleaning members 35 and 36 are formed of a member having a predetermined elasticity such as a PET film, even if the toner adheres to the surface of the guide rib 33 and becomes hardened, it can be easily removed. Can be removed. Even if the rib cleaning members 35 and 36 are in direct contact with the guide rib 33, the guide rib 33 can be prevented from being damaged.

  In the above embodiment of the present invention, the rib cleaning member is provided at two locations on the upper side and the lower side of the guide rib. However, only one of the rib cleaning members may be provided. The rib cleaning member is not limited to a PET film, and may be a thin stainless film or the like as long as it has elasticity instead of the PET film. Furthermore, the rib cleaning member does not have to be plate-shaped like a film, and may be brush-shaped.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in all image forming apparatuses that use a movable guide to perform an operation of distributing a sheet to a plurality of sheet conveyance paths.

1 is a schematic vertical sectional front view of a printer which is an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a partially enlarged schematic vertical cross-sectional view illustrating the periphery of a sheet guide device and a fixing unit in FIG. 1. It is a fragmentary perspective view of the movable guide shown in FIG. FIG. 3 is an enlarged schematic vertical cross-sectional view of the movable guide shown in FIG. 2 and shows a state in which the movable guide is in a posture to feed a sheet to a discharge sheet conveyance path. FIG. 3 is an enlarged schematic vertical sectional view of the movable guide shown in FIG. 2 and shows a state in which the movable guide is in a posture to feed the paper to the reversing paper conveyance path.

Explanation of symbols

1 Printer (image forming device)
2 Main body 20 Fixing unit 30 Paper guide device 31 Movable guide 33 Guide ribs 33b and 33c Downstream portion in paper conveyance direction 35 Upper rib cleaning member 36 Lower rib cleaning member 40 Ejecting paper conveyance path 50 Reversing paper conveyance path

Claims (3)

  A guide rib for guiding the paper is provided, and a movable guide capable of changing the angle to distribute the paper into two paper transport paths and a fixed guide constituting the paper transport path correspond to the guide ribs of the movable guide. A sheet guide device for an image forming apparatus, comprising: a rib cleaning member that is provided at a position where the movable guide is angled and contacts a sheet contact position of the guide rib along with a change in the angle of the movable guide.   The paper guide device for an image forming apparatus according to claim 1, wherein the rib cleaning member is in contact with a downstream portion in a paper transport direction of a paper contact portion of the guide rib.   The sheet guide device for an image forming apparatus according to claim 1, wherein the rib cleaning member is a member having a predetermined elasticity.

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