JP2007217156A - 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 loading properties of a sheet to be delivered irrespective of the type of a sheet used in the formation of image, and to provide an image forming device equipped with it. <P>SOLUTION: This sheet delivery mechanism is composed of a pair of delivery rollers 14, a sheet delivery port 15, a sheet pressing member 17, and a pressing force adjusting member 18. The rear surface of the sheet pressing member 17 is abutted on an abutting part 18b of the pressing force adjusting member 18 so that the pressing force adjusting member 18 slides in the vertical direction to adjust the bending of a pressing part 17a in the direction of sheet delivery. <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 2 that rotates clockwise in the drawing is uniformly charged by a charging unit 3, and an exposure unit (laser scanning unit) based on document image data. Etc.) An electrostatic latent image is formed on the photosensitive drum 2 by the laser beam from 4, and a developer (hereinafter referred to as toner) is attached to the electrostatic latent image by the developing unit 5 to form a toner image.

  The toner is supplied to the developing unit 5 from the toner container 6. 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 2 is provided on the downstream side of the cleaning device 7.

  A sheet is conveyed from the sheet feeding cassette 8 through the sheet supply path 9 and the registration roller pair 10 toward the photosensitive drum 2 on which the toner image is formed as described above, and is transferred by the transfer roller 11 (image transfer unit). The toner image formed on the surface of the photosensitive drum 2 is transferred to the sheet. The sheet onto which the toner image has been transferred is separated from the photosensitive drum 2 and conveyed to the fixing unit 12 having the fixing roller pair 12a to fix the toner image. The sheet that has passed through the fixing unit 12 is conveyed to the upper part of the apparatus by the sheet conveying path 13 and is discharged onto the discharge tray 16 from the sheet discharge port 15 via the discharge roller 14.

  In such an image forming apparatus, the sheet heated and pressed by the fixing unit 12 may be largely curled (rolled) depending on conditions. FIG. 7A is a perspective view showing a state in which the sheets S are stacked on the discharge tray (see FIG. 6), and FIG. 7B is a view as seen from the direction of the arrow B. . FIG. 7 shows a state in which the left and right side portions S1 of the sheet S 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 S changes depending on the roller pressure of the pressure roller of the fixing unit, the curl height h of the left and right side portions S1 is about 30 mm when it is large. When the sheet S is locally curled in this manner, the sheet discharge port 15 is blocked, the alignment and stackability of the sheet S discharged onto the discharge tray 16 are remarkably impaired, and the previously stacked sheet S is discharged. There was also a risk of being pushed out in the direction and falling from the discharge tray 16.

  Therefore, as disclosed in Patent Documents 1 and 2, conventionally, a sheet pressing member 17 is extended from the upper part of the sheet discharge port 15 substantially vertically downward with respect to the sheet conveying direction, and the curled sheet is pressed. Sheet alignment and stackability were improved. As shown in FIG. 8, the sheet pressing member 17 is arranged at two left and right positions of the sheet discharge port 15, and is configured to press both left and right end portions of the sheet S that is particularly likely to be curled.

  FIG. 9 is an enlarged cross-sectional view of the vicinity of the sheet pressing member 17 shown in FIG. The left and right ends of the sheet S that has been transported through the sheet transport path 13 composed of the transport guides 13 a and 13 b are directed toward the discharge tray 16 by a sheet pressing member 17 that extends substantially vertically downward when passing through the sheet discharge port 15. This improves the alignment and stackability on the discharge tray 16.

By the way, in recent years, various sheets have been used for image formation, and it is necessary to adjust the pressing force of the sheet pressing member as described above according to the type of sheet used. For example, if a thick sheet is used, or if the moisture content is high and the curl is large, it is necessary to increase the pressing force. If a thin sheet is used, jamming may occur if the pressing force is too strong. Therefore, it is necessary to weaken the pressing force.
Japanese Patent Laid-Open No. 10-265113 JP 2003-81514 A

  However, in the configuration of the pressing member as in Patent Document 1, the pressing force applied to the sheet passing through the discharge port by the sheet pressing member is always constant, and cannot be applied to various sheets. Further, in the configuration of the pressing member as in Patent Document 2, since the sheet pressing member can be attached to and detached from the apparatus main body, it can be replaced with a sheet pressing member having a different pressing force, but the replacement work is complicated. is there.

  In the present invention, in view of the above problems, the pressing force of the sheet pressing member can be easily adjusted, and the stackability of discharged sheets can be improved regardless of the type of sheet used for image formation. An object of the present invention is to provide a sheet discharge mechanism and an image forming apparatus including the sheet discharge mechanism easily and at low cost.

  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. And a pressing force adjusting member that adjusts the pressing force applied to the sheet passing through the sheet discharge port by adjusting the amount of deflection of the sheet pressing member in the sheet discharging direction. .

  According to the present invention, the pressing force adjusting member is attached to a back surface of the sheet pressing member so as to be slidable in a vertical direction, and projects from the mounting portion in a substantially horizontal direction to protrude from the back surface of the sheet pressing member. The amount of bending of the sheet pressing member in the sheet discharge direction can be adjusted by moving the contact position between the contact portion and the sheet pressing member in the vertical direction. It is characterized by that.

  According to the present invention, there is provided a locking piece that is selectively disposed at a locking position that restricts sliding of the pressing force adjusting member and a sliding position that enables the pressing force adjusting member to slide. It is said.

  According to the present invention, in the sheet discharge mechanism configured as described above, the sheet pressing member includes a pressing portion that contacts the sheet and presses the sheet downward, and a mounting portion that is fixed to an upper end of the sheet discharge port is substantially vertical. It is characterized in that it is integrally formed.

  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 bending of the sheet pressing member formed of a flexible film in the sheet discharge direction due to the pressing force of the sheet passing through the sheet discharge port is adjusted by the pressing force adjusting member. Since the pressing force applied to the sheet can be adjusted, the optimal pressing force can be adjusted according to the type of paper used. Can be improved.

  Further, according to the second configuration of the present invention, in the sheet discharge mechanism of the first configuration, the deflection of the sheet pressing member can be adjusted only by sliding the pressing force adjusting member in the vertical direction. It is possible to easily adjust the pressing force applied to the sheet.

  Further, according to the third configuration of the present invention, in the sheet discharge mechanism of the second configuration, the locking piece provided on the pressing force adjusting member is provided with a plurality of locking holes provided on the mounting surface. Since the position of the pressing force adjusting member is determined by inserting it into one of them, if the pressing force of the sheet pressing member obtained for each locking hole is determined, by selecting a predetermined locking hole Since it can be adjusted to the target pressing force, it can be easily adjusted.

  According to the fourth configuration of the present invention, in the sheet discharge mechanism having any one of the first to third configurations, the pressing portion that contacts the left and right ends of the sheet and presses the sheet downward, and the sheet discharge mechanism. Since the attachment portion fixed to the upper end of the outlet 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.

  Further, according to the fifth configuration of the present invention, by mounting the sheet discharge mechanism having any one of the first to fourth configurations, the discharge tray can be mounted regardless of the type of paper used for image formation. The present invention provides an easy-to-use image forming apparatus that improves the stackability of discharged sheets.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing the configuration of an image forming apparatus provided with a sheet discharge mechanism according to the present invention. FIG. 2 is an exploded perspective view of the sheet discharge mechanism of the present invention. 1 and 2, the same reference numerals are given to the portions common to FIG. 8 of the conventional example, and the description is omitted.

  As shown in FIGS. 1 and 2, the sheet discharge mechanism includes a discharge roller pair 14, a sheet discharge port 15, a sheet pressing member 17, and a pressing force adjusting member 18. One sheet pressing member 17 is disposed on each of the left and right sides of the sheet discharge port 15, and a pressing force adjusting member 18 is provided for each sheet pressing member 17.

  FIG. 3 is a perspective view of the sheet pressing member 17. FIG. 3 shows only the sheet pressing member 17 disposed on the right side toward the sheet discharge port 15, but this also has the same configuration for the sheet pressing member 17 disposed on the left side. . The sheet pressing member 17 is in contact with the left and right side portions S1 (see FIG. 7) of the sheet S discharged from the sheet discharge port 15 (see FIG. 1) and presses down, and a double-sided adhesive tape 19 is interposed therebetween. A mounting portion 17b fixed to the upper end of the sheet discharge port 15 is integrally formed.

  As shown in FIG. 2, the sheet pressing member 17 is fixed to the back surface of the exterior cover 1 a constituting the upper surface of the sheet discharge port by the double-sided adhesive tape 19. The pressing portion 17a and the mounting portion 17b are in a substantially vertical positional relationship, and the pressing force of the sheet S conveyed from the discharge roller pair 14 is parallel to the mounting portion 17b, that is, with the peeling direction of the mounting portion 17b. Acts in a substantially vertical direction. For this reason, peeling of the sheet pressing member 17 due to the pressing force of the sheet S hardly occurs.

  The material of the sheet pressing member 17 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 curling of the sheet S 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 17 are not particularly limited, and may be set as appropriate depending on the size of the sheet discharge port 15, 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.

  FIG. 4 is a perspective view of the pressing force adjusting member 18. 4 illustrates only the pressing force adjusting member 18 disposed on the right side toward the sheet discharge port 15 and does not illustrate the pressing force adjusting member 18 disposed on the left side. The configuration is the same except that they are arranged symmetrically. The pressing force adjusting member 18 includes a mounting portion 18a that is a rectangular plate member that is engaged with the upper vertical surface 15a of the sheet discharge port 15, and a contact portion 18b that contacts the sheet pressing member 17 and tilts the mounting portion 18a. The contact portion 18b is integrally formed in an L shape so as to form a right angle at the lower end edge portion on the surface side of the attachment portion 18a.

  Further, on the back side of the mounting portion 18a, engagement pieces 18c are provided on both left and right edges, and the engagement pieces 18c are inserted into a sliding groove 15b formed on the vertical surface 15a and extending in the vertical direction. Thus, the pressing force adjusting member 18 is engaged with the vertical surface 15a so as to be slidable in the vertical direction. Note that a hooking claw (not shown) is formed at the tip of the engagement piece 18c so that it does not come off the vertical surface 15a even if the pressing force adjusting member 18 slides.

  Further, a locking piece 20 is disposed at the right end of the contact portion 18b. The locking piece 20 is formed in an L shape, and one end of the locking piece 20 is rotatably supported by the contact portion 18b by the rotation shaft 20a, and the other end is a locking hole 15c provided in the vertical surface 15a. A locking position (a position indicated by a solid line in FIG. 4) and a sliding position (a position indicated by a dotted line in FIG. 4) extracted from the locking hole 15c can be taken. Here, a plurality of the locking holes 15c are provided in parallel with the sliding groove 15b, and after the pressing force adjusting member 18 is slid, the locking piece 20 is rotated to enter any of the locking holes 15c. By inserting, the pressing force adjusting member 18 can be fixed at that position.

  When the exterior cover 1a to which the sheet pressing member 17 is fixed is attached to the main body of the image forming apparatus 1, the sheet pressing member 17 is engaged with the upper vertical surface 15a of the sheet discharge port 15, as shown in FIG. The pressing force adjusting member 18 is positioned so as to cover the lower surface of the sheet pressing member 17 and the abutting portion 18b of the pressing force adjusting member 18, and the pressing force adjusting member 18 is slid in the vertical direction. By making it move, the bending of the sheet pressing member 17 in the sheet discharge direction can be adjusted.

  Adjustment of the pressing force of the sheet pressing member 17 using the pressing force adjusting member 18 in the sheet discharge mechanism configured as described above will be described with reference to FIG. 5 is an enlarged cross-sectional view of the periphery of the sheet pressing member 17 shown in FIG. 1, in which (a) shows a state in which the pressing force adjusting member 18 is slid downward, and (b) is a pressing force adjusting member. A state in which 18 is slid upward is illustrated. In (a) and (b), the broken line indicates the position of the sheet pressing member 17 when the sheet S passes through the sheet discharge port 15.

  First, a case where the pressing force adjusting member 18 is slid downward is described. When the pressing force adjusting member 18 is slid downward, as shown in FIG. 5A, the contact position with the sheet pressing member 17 is positioned at the lowest position, and the sheet discharge direction of the pressing portion 17a (in the drawing) The rightward deflection is the smallest. When the sheet passes through the sheet discharge port 15 in this state, the pressing portion 17a is bent in the sheet discharge direction by the bending amount C by the pressing force of the passing sheet. Here, since the pressing force applied to the passing sheet is the repulsive force (elastic force) of the pressing portion 17a, the pressing force corresponding to the deflection amount C is applied to the sheet.

  Next, when the pressing force adjusting member 18 is slid to the uppermost position, as shown in FIG. 5 (b), the contact position with the sheet pressing member 17 is positioned at the uppermost position, and the sheet discharging direction of the pressing portion 17a. The deflection to the largest is the largest. When the sheet passes through the sheet discharge port 15 in this state, the pressing portion 17a is bent in the sheet discharge direction by the pressing force of the passing sheet, but is bent in advance by the pressing force adjusting member 18. Therefore, the amount of deflection is smaller than C, and the amount of deflection due to the pressing force of the sheet is D. Therefore, the pressing force applied to the passing sheet is weakened by the difference between the deflection amount C and the deflection amount D.

  As described above, by bending the sheet pressing member 17 in the sheet discharging direction in advance by the pressing force adjusting member 18, the amount of bending of the sheet pressing member 17 due to the pressing force of the sheet passing through the sheet discharge port 15 can be reduced. Since it can be adjusted and the repulsive force (elastic force) of the sheet pressing member 17 can be adjusted, the pressing force applied to the sheet passing through the sheet discharge port can be adjusted.

  In addition, this invention is not limited to said each embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the method of fixing the sheet pressing member 17 is not limited to the double-sided adhesive tape 19, and an adhesive or adhesive may be applied to the pressing portion 17a, or may be fixed using screws, rivets, etc. The shape is not limited to a rectangular shape. For example, the front end may have an angle with respect to the discharge tray, and a slit that divides the front end of the sheet pressing member into a plurality of portions may be provided.

  In addition, the shape and size of the pressing force adjusting member 18 can be changed as appropriate, and the locking method can also be changed. Furthermore, in the above embodiment, the pressing force adjusting member 18 is provided for each sheet pressing member 17, but this can simultaneously adjust the pressing force of the plurality of sheet pressing members 17 by one pressing force adjusting member 18. You may do it. 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 can be used for 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.

FIG. 3 is a perspective view of an image forming apparatus equipped with the sheet discharge mechanism of the present invention. These are exploded perspective views of the sheet discharge mechanism of the present invention. FIG. 3 is a perspective view of a sheet pressing member. FIG. 3 is a perspective view of a pressing force adjusting member. FIG. 4 is an enlarged cross-sectional view showing a configuration around a sheet discharge port in the image forming apparatus of the present invention, where (a) illustrates a state in which the pressing force adjusting member is slid downward, and (b) illustrates pressing force adjustment A state in which the member is slid upward is illustrated. 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 1a Exterior cover 13 Sheet conveyance path 13a, 13b Conveyance guide 14 Discharge roller pair 15 Sheet discharge port 15a Vertical surface 15b Sliding groove 15c Locking hole 16 Discharge tray 17 Sheet pressing member 17a Holding part 17b Mounting part 18 Pushing Pressure adjusting member 18a Mounting portion 18b Abutting portion 18c Engagement piece 19 Double-sided adhesive tape 20 Locking piece 20a Rotating shaft S Sheet S1 Left and right side portions

Claims (5)

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 the pressing force applied to the sheet passing through the sheet discharge port is adjusted by adjusting the amount of bending of the sheet pressing member in the sheet discharging direction. A sheet discharge mechanism provided with a pressing force adjusting member.   The pressing force adjusting member is attached to a back surface of the sheet pressing member so as to be slidable in the vertical direction, and abutting to protrude from the mounting portion in a substantially horizontal direction to contact the back surface of the sheet pressing member. The amount of bending of the sheet pressing member in the sheet discharge direction can be adjusted by moving the contact position between the contact portion and the sheet pressing member in the vertical direction. The sheet discharge mechanism according to claim 1.   3. A locking piece that is selectively disposed at a locking position that restricts sliding of the pressing force adjusting member and a sliding position that enables the pressing force adjusting member to slide. The image forming apparatus described in 1.   2. The sheet pressing member according to claim 1, wherein a pressing portion that contacts the sheet and presses the sheet downward and a mounting portion that is fixed to an upper end of the sheet discharge port are integrally formed substantially vertically. The sheet discharge mechanism according to any one of claims 1 to 3.   An image forming apparatus comprising the sheet discharge mechanism according to claim 1.

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