JP2007106524A - Sheet delivery mechanism and image forming device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet delivery mechanism capable of improving aligning property and loading property of sheets to be delivered irrespective of degree of curling of sheet and to provide an image forming device equipped with it. <P>SOLUTION: This sheet delivery mechanism is composed of a pair of delivery rollers 16, a sheet delivery port 19, and a sheet pressing member 20. Tips of the sheet pressing members 20 provided on both left and right sides of the sheet delivery port 19 have predetermined angles for a horizontal face so that they approach an upper face of a delivery tray as they advance in the directions of both left and right ends. Consequently, since the sheet whose both left and right side parts are curled passes through the sheet delivery port 19 while coming into contact with an outer side part of a tip part of the sheet pressing member 20 much more, the sheet pressing member 20 is sufficiently bent in, in particular, both left and right side parts where curling is conspicuous to suppress curling of both left and right side parts effectively. Since both left and right ends of sheet come into contact with slope of the tip part, sheets are aligned in the direction crossing the direction of conveyance orthogonally. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet discharge mechanism for discharging a sheet-like paper or a document used in an image forming apparatus such as a digital copying machine or a laser printer, and an image forming apparatus including the same.

  The configuration of a conventional image forming apparatus is shown in FIG. In an image forming apparatus (for example, a printer) 1, when performing an image forming operation, a photosensitive drum 5 that rotates clockwise in the drawing is uniformly charged by a charging unit 4, and an exposure unit (laser scanning unit) based on document image data. Etc.) An electrostatic latent image is formed on the photosensitive drum 5 by the laser beam from 7, and a developer (hereinafter referred to as toner) is attached to the electrostatic latent image by the developing unit 8 to form a toner image.

  The toner is supplied to the developing unit 8 from the toner container 9. The image data is transmitted from a personal computer (not shown) or the like. Further, a static elimination device (not shown) for removing residual charges on the surface of the photosensitive drum 5 is provided on the downstream side of the cleaning device 18.

  A sheet is conveyed from the sheet feeding cassette 10 via the sheet conveyance path 11 and the registration roller pair 12 toward the photosensitive drum 5 on which the toner image is formed as described above, and is transferred by the transfer roller 13 (image transfer unit). The toner image formed on the surface of the photosensitive drum 5 is transferred to the sheet. The sheet onto which the toner image has been transferred is separated from the photosensitive drum 5 and conveyed to a fixing unit 14 having a fixing roller pair 14a to fix the toner image. The sheet that has passed through the fixing unit 14 is conveyed to the upper part of the apparatus by the sheet conveying path 15 and is discharged onto the discharge tray 17 from the discharge port 19 via the discharge roller pair 16.

  In such an image forming apparatus, the sheet heated and pressed by the fixing unit 14 may be largely curled (rolled) depending on conditions. 8A is a perspective view showing a state in which the sheets 2 are stacked on the discharge tray (see FIG. 7), and FIG. 8B is a view as viewed from the direction of the arrow B, showing one sheet 2. . FIG. 8 shows a state in which the left and right side portions 2a of the sheet 2 discharged along the sheet discharge direction (the direction of arrow A in the figure) are particularly curled.

  Since the degree of curling of the sheet 2 varies depending on the roller pressure of the pressure roller of the fixing unit, the curl height h of the left and right side portions 2a is about 30 mm when large. When the sheet is curled locally in this way, the discharge port is blocked, the alignment and stackability of the sheet discharged onto the discharge tray are remarkably impaired, and the previously stacked sheet is pushed out in the discharge direction and discharged. There was also a risk of falling from the tray.

  Therefore, conventionally, as disclosed in Patent Documents 1 and 2, the sheet pressing member 20 is extended from the upper portion of the discharge port 19 substantially vertically downward with respect to the sheet conveying direction, and the sheet is pressed by pressing the curled sheet. Alignment and loadability were improved. As shown in FIG. 9, the sheet pressing members 20 are arranged at two left and right positions of the discharge port 19, and are configured to press both left and right end portions of the sheet that are particularly likely to curl.

  FIG. 10 is an enlarged cross-sectional view around the sheet pressing member 20. Both ends of the sheet conveyed through the sheet conveyance path 15 including the conveyance guides 15a and 15b are pressed in the direction of the discharge tray 17 by the sheet pressing member 20 extending substantially vertically downward when passing through the discharge port 19. The alignment and loading on the discharge tray 17 are improved.

However, in the configuration of the pressing member as in Patent Documents 1 and 2, the pressing force by the sheet pressing member 20 may not be sufficiently applied to the sheet discharged onto the discharge tray 17. For this reason, when the left and right ends of the sheet are particularly curled, the curled portion comes into contact with the sheets sequentially discharged from the discharge port, and this is not a countermeasure for preventing sheet stacking disturbance or dropping from the discharge tray. It was enough.
Japanese Patent Laid-Open No. 10-265113 JP 2003-81514 A

  In view of the above problems, the present invention provides a sheet discharge mechanism that improves the alignment and stackability of discharged sheets regardless of the degree of curling of the sheets, and an image forming apparatus including the same, at a low cost. The purpose is to provide.

  In order to achieve the above object, the present invention extends a sheet discharge port, a pair of discharge rollers provided in the vicinity of the sheet discharge port, and substantially vertically downward with respect to the conveying direction at both left and right ends of the sheet discharge port. A sheet pressing member that presses both ends of the sheet passing through the sheet discharge port, and sequentially discharges and stacks the sheets on a discharge tray. The sheet pressing member is formed of a flexible film. The front end portion has a predetermined angle with respect to a horizontal plane so as to approach the upper surface of the discharge tray toward the left and right ends of the sheet discharge port.

  In the sheet discharge mechanism having the above-described configuration, the sheet pressing member includes a pressing portion that contacts the left and right ends of the sheet and presses the sheet downward, and an attachment portion that is fixed to an upper end of the sheet discharge port. Are integrally formed substantially vertically.

  According to the present invention, in the sheet discharge mechanism configured as described above, the sheet pressing member is formed by arranging rectangular flexible films at left and right ends of the sheet discharge port at a predetermined angle with respect to a horizontal plane. Yes.

  The present invention also provides an image forming apparatus including the sheet discharge mechanism having the above-described configuration.

  According to the first configuration of the present invention, the sheet with the left and right sides curled passes through the sheet discharge port while making more contact with the outer portion of the front end portion of the sheet pressing member. The sheet pressing member is sufficiently bent at the portion, and the curls at the left and right side portions can be effectively suppressed. In addition, since the left and right ends of the sheet are in contact with the inclination of the leading end, the sheets can be stacked while being aligned in a direction perpendicular to the conveyance direction.

  Further, according to the second configuration of the present invention, in the sheet discharge mechanism of the first configuration, the pressing portion that contacts the left and right ends of the sheet and presses the sheet downward is fixed to the upper end of the sheet discharge port. Since the attachment portion is integrally formed substantially vertically using a flexible film, the sheet pressing member can be produced easily and at low cost. Further, since the pressure of the sheet conveyed from the pair of discharge rollers acts in a direction substantially perpendicular to the peeling direction of the attachment portion, the sheet pressing member fixed to the sheet discharge port is difficult to come off.

  According to the third configuration of the present invention, in the sheet discharge mechanism according to the first configuration, a rectangular flexible film is disposed at both left and right ends of the sheet discharge port at a predetermined angle with respect to a horizontal plane. By using the pressing member, the angle of the leading end of the sheet pressing member can be arbitrarily set only by changing the arrangement angle of the flexible film, and thus the curling suppression force generated on the sheet can be varied.

  In addition, according to the fourth configuration of the present invention, by mounting the sheet discharge mechanism having any one of the first to third configurations, the alignment and stackability of the sheets discharged onto the discharge tray are improved. Provided is an easy-to-use image forming apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view illustrating a configuration of an image forming apparatus including a sheet discharge mechanism according to the first embodiment of the present invention. Portions common to FIG. 9 of the conventional example are denoted by the same reference numerals and description thereof is omitted. In FIG. 1, the sheet discharge mechanism is composed of a discharge roller pair 16, a sheet discharge port 19, and a sheet pressing member 20, and the front ends of the sheet pressing members 20 provided on the left and right sides of the sheet discharge port 19 are both left and right ends. It has a predetermined angle with respect to a horizontal plane so that it may approach the upper surface of a discharge tray, so that it goes to a direction.

  FIG. 2 is a perspective view of a sheet pressing member used in the sheet discharge mechanism of the first embodiment. The sheet pressing member 20 is in contact with the left and right side portions 2 a (see FIG. 8) of the sheet discharged from the sheet discharge port 19 (see FIG. 1) and presses downward, and a double-sided adhesive tape 21. A mounting portion 20b fixed to the upper end of the sheet discharge port 19 is integrally formed.

  The pressing portion 20a and the mounting portion 20b are in a substantially vertical positional relationship, and the pressing force of the sheet conveyed from the discharge roller pair 16 (see FIG. 1) is parallel to the mounting portion 20b, that is, the peeling of the mounting portion 20b. Acts in a direction substantially perpendicular to the direction. For this reason, peeling of the sheet pressing member 20 due to the pressing force of the sheet hardly occurs. The front end portion 22 of the pressing portion 20a is adjusted to have an angle a with respect to the horizontal plane when the attachment portion 20b is fixed.

  The angle a varies depending on the degree of curling of the sheet and the specification of the sheet pressing member 20, but is set to about 15 to 20 °, for example. Although the sheet pressing member 20 disposed on the left side toward the sheet discharge port 19 has been described with reference to FIG. 2, the sheet pressing member 20 disposed on the right side also has a configuration in which the tip portion 22 is inclined in the opposite direction. The configuration is exactly the same.

  The material of the sheet pressing member 20 is not particularly limited as long as it is a flexible synthetic resin film or the like, but a film having a strength that can suppress the curling of the sheet is preferable. As such a film, for example, a polyethylene terephthalate (PET) film (Lumirror film) is preferably used. Further, the size and thickness of the sheet pressing member 20 are not particularly limited, and may be set as appropriate depending on the size of the sheet discharge port 19, the size of the conveyed sheet, and the like. You need to have power. Therefore, for example, in the case of a PET film, the thickness of the film is preferably 0.1 mm or more.

  Next, the operation of the sheet discharge mechanism of the present invention will be described. FIG. 3 is a front cross-sectional view showing a state in which the sheet 2 (see FIG. 8) whose left and right side portions are curled is discharged from the sheet discharge port 19 (see FIG. 1). For convenience of explanation, only the sheet 2 and the sheet pressing member 20 are shown here. Since the angle a is provided at the front end portion 22 of the sheet pressing member 20 so as to approach the upper surface of the discharge tray 17 (see FIG. 1) as it goes outward, the sheet 2 with the left and right side portions 2a curled is The sheet pressing member 20 is passed while making more contact with the outer portion of the portion 22.

  As a result, the sheet pressing member 20 is sufficiently bent at both the left and right side portions 2a where the curl is particularly noticeable, so that the repulsive force (elastic force) of the sheet pressing member 20 is also increased, and as shown in FIG. The curl height h (see FIG. 8) can be held down to h ′ (h> h ′).

  As shown in FIG. 4, the front end portions 22 of the left and right sheet pressing members 20 each have an angle a with respect to the horizontal plane, so that the sheet 2 comes into contact with the inclination of the front end portion 22 when passing through the sheet pressing member 20. However, it is brought inward (arrow direction in the figure). That is, the sheet pressing member 20 also has an effect of aligning the sheets in a direction perpendicular to the conveyance direction.

  FIG. 5 is an external perspective view illustrating a configuration of an image forming apparatus including a sheet discharge mechanism according to the second embodiment of the present invention. Portions common to FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, rectangular sheet pressing members 20 on the left and right sides of the sheet discharge port 19 have a predetermined angle a with respect to the horizontal plane so that the leading end approaches the upper surface of the discharge tray as it goes in the left and right ends. Has been placed.

  With this configuration, it is possible to arbitrarily set the angle of the tip with respect to the horizontal plane simply by adjusting the mounting angle a of the rectangular sheet pressing member 20, so that the curling suppression force generated on the sheet can be freely varied. Can do. Further, since it is not necessary to bend the film to form the attachment portion, it is advantageous in terms of manufacturing cost of the sheet pressing member. Note that the curl suppressing action and the sheet aligning action when the sheet discharge mechanism of the present embodiment is used are the same as those in the first embodiment, and the description thereof is omitted.

  In the second embodiment, the rectangular sheet pressing member 20 is attached to the sheet discharge port 19 at an angle. However, like the sheet pressing member 20 used in the first embodiment, the pressing portion 20a and the mounting portion are attached. It is good also as a structure which consists of the part 20b. In this case, as in the first embodiment, the pressure of the discharged sheet acts in a direction substantially perpendicular to the peeling direction of the mounting portion 20 b, so that the sheet pressing member 20 is unlikely to come off from the sheet discharge port 19. The attachment portion 20b can be easily provided by bending the upper end of the rectangular sheet pressing member obliquely as shown in FIG. In addition, the angle a of the tip 22 can be arbitrarily set by adjusting the bending angle.

  In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the method of fixing the sheet pressing member 20 is not limited to the double-sided adhesive tape 21, and an adhesive or adhesive may be applied to the pressing portion 20a, or may be fixed using screws, rivets, or the like. good. The sheet discharge mechanism of the present invention can be applied to various image forming apparatuses such as analog and digital monochrome copying machines, color copying machines, facsimile machines, and printers.

  The present invention relates to a sheet discharge port, a pair of discharge rollers provided in the vicinity of the sheet discharge port, and a sheet that extends substantially vertically downward with respect to the conveyance direction at the left and right ends of the sheet discharge port and passes through the sheet discharge port. A sheet pressing mechanism that sequentially discharges and stacks sheets on a discharge tray. The sheet pressing member is formed of a flexible film, and the leading end of the sheet pressing member is a sheet discharge member. It has a predetermined angle with respect to a horizontal plane so that it may approach the upper surface of a discharge tray, so that it goes to the left-right both ends direction of an exit.

  As a result, the sheet pressing member can be sufficiently bent at both the left and right side portions of the sheet with particularly curling, and the left and right side curl portions can be effectively pressed. The sheets can be aligned in a direction perpendicular to the conveying direction. Therefore, it is possible to provide a sheet discharge mechanism with stable alignment and stackability to the discharge tray.

  In addition, if a pressing part that contacts the left and right ends of the sheet and presses the sheet downward and an attachment part that is fixed to the upper end of the sheet discharge port are integrally formed substantially vertically with a single film, The configuration of the sheet pressing member is simplified, contributing to cost reduction of the sheet discharge mechanism, and suppressing the sheet pressing member from being detached due to the pressure of the discharged sheet.

  In addition, by arranging a rectangular flexible film at a predetermined angle with respect to the horizontal plane to form a sheet pressing member, the angle of the front end of the sheet pressing member can be arbitrarily changed simply by changing the arrangement angle of the flexible film. Since it can be set, the curling suppression force generated on the sheet can be varied, and it is not necessary to bend the film, so that further cost reduction can be achieved.

  In addition, if the sheet discharge mechanism of the present invention is installed in an image forming apparatus such as a copying machine or a printer, sheets can be stacked and stacked on the discharge tray, and dropping of the sheet from the discharge tray can be suppressed. .

1 is a perspective view of an image forming apparatus equipped with a sheet discharge mechanism according to a first embodiment of the present invention. These are perspective views which show the structure of the sheet | seat pressing member used for the sheet | seat discharge mechanism of 1st Embodiment. These are sectional drawings explaining a mode that the curl of the both ends of a sheet | seat is pressed down by a sheet | seat pressing member. FIG. 6 is a front view illustrating a state in which sheets are aligned in a direction perpendicular to the conveyance direction by a sheet pressing member. These are perspective views of an image forming apparatus equipped with a sheet discharge mechanism of a second embodiment of the present invention. These are perspective views which show the other structure of the sheet | seat pressing member used for the sheet | seat discharge mechanism of 2nd Embodiment. FIG. 1 is a schematic cross-sectional view showing an overall configuration of a conventional image forming apparatus. These are the perspective view and side view which show the state which the left and right both ends of the sheet | seat curled. FIG. 3 is a perspective view of a conventional image forming apparatus. FIG. 9 is an enlarged cross-sectional view illustrating a configuration around a sheet discharge port in a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Sheet 2a Left and right both ends 16 Discharge roller pair 17 Discharge tray 19 Sheet discharge port 20 Sheet pressing member 20a Holding part 20b Mounting part 21 Double-sided adhesive tape 22 Tip part

Claims (4)

A sheet discharge port, a discharge roller pair provided in the vicinity of the sheet discharge port, and both ends of the sheet extending substantially vertically downward with respect to the conveying direction at the left and right ends of the sheet discharge port and passing through the sheet discharge port. A sheet pressing mechanism that presses, and sequentially discharges and stacks sheets on a discharge tray.
The sheet pressing member is formed of a flexible film, and a leading end portion of the sheet pressing member has a predetermined angle with respect to a horizontal plane so as to approach the upper surface of the discharge tray toward the left and right ends of the sheet discharge port. Characteristic sheet discharge mechanism.   The sheet pressing member is characterized in that a pressing portion that contacts the left and right ends of the sheet and presses the sheet downward and an attachment portion that is fixed to the upper end of the sheet discharge port are integrally formed substantially vertically. The sheet discharge mechanism according to claim 1.   The sheet discharge mechanism according to claim 1, wherein the sheet pressing member is formed by arranging rectangular flexible films at left and right ends of the sheet discharge port at a predetermined angle with respect to a horizontal plane.   An image forming apparatus comprising the sheet discharge mechanism according to claim 1.

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