JP2007076805A - Paper delivery device for image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper delivery device capable of delivering a paper having small size while preventing disorder of attitude and preventing a paper having large size from being pushed out of a paper delivery tray. <P>SOLUTION: This paper delivery device has a pair of paper delivery rollers 20 for delivering a paper on which image is formed in an image forming part 3a toward the paper delivery tray 11. The pair of paper delivery rollers 20 is composed of a driving roller 21 and a driven roller 22. The driven roller 22 is constituted to turn around a shaft 21a of the driving roller 21 and change the direction of paper delivery for the paper delivery tray 11 vertically. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper discharge device of an image forming apparatus (printer, facsimile, copier, etc.).

2. Description of the Related Art Conventionally, a sheet discharge roller pair that discharges a sheet (sheet-like recording material) on which an image is formed in an image forming unit to a sheet discharge tray is provided. The sheet discharge roller pair includes a drive roller and a drive roller. 2. Description of the Related Art A paper discharge device for an image forming apparatus that includes a driven roller that is in contact with and driven by a roller is known (see, for example, Patent Document 1).
In the conventional paper discharge device, the paper discharge direction (the paper discharge direction and the paper discharge angle with respect to the paper discharge tray as viewed from the axial direction of the roller) by the contact portion (nip portion) between the driving roller and the driven roller is constant. Met.
JP 2004-323137 A

In the above-described conventional paper discharge device of the image forming apparatus, the paper discharge direction by the contact portion between the driving roller and the driven roller is constant, causing the following problems.
For example, as shown in FIG. 8B, when the paper discharge direction F1 ′ by the paper discharge roller pair 1 is directed upward, when the paper S is a small size (for example, a postcard), it is shown in FIG. Thus, the posture of the paper S discharged onto the paper discharge tray 2 is likely to be disturbed. This is because the time until the paper trailing edge leaves the paper discharge roller pair 1 and falls on the paper discharge tray 2 increases.
Such a problem can be solved by, for example, directing the paper discharge direction F2 ′ by the paper discharge roller pair 1 downward as compared to the paper discharge direction F1 ′ as shown in FIG. 8C.
However, when the paper discharge direction F2 ′ by the paper discharge roller pair 1 is directed downward, when the paper S is a large size (for example, A3 size), as shown in FIG. Another problem arises in that the paper S1 that is subsequently discharged is strongly pressed against the paper S1 that has been discharged first, and the previous paper S1 is easily pushed out from the paper discharge tray 2.
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper discharge device for an image forming apparatus that solves the above-described problems and discharges small-sized paper with little disturbance in posture and prevents large-size paper from being pushed out of a paper discharge tray. There is.

In order to achieve the above object, the paper discharge device of the image forming apparatus of the present invention has a pair of paper discharge rollers for discharging the paper on which an image has been formed in the image forming unit toward the paper discharge tray. A pair of rollers is a paper discharge device of an image forming apparatus composed of a driving roller and a driven roller that is driven in contact with the driving roller;
The driven roller is configured to be rotatable about the axis of the driving roller, and the discharge direction with respect to the discharge tray is configured to be variable up and down.
According to such a configuration, when the paper to be discharged is a small size, the driven roller is rotated downward around the axis of the driving roller to direct the paper discharge direction to the paper discharge tray downward. Thus, a small-size sheet can be discharged with less posture disturbance.
On the other hand, when the paper to be discharged is large, the driven roller is rotated upward around the axis of the driving roller so that the paper discharge direction with respect to the paper discharge tray is directed upward. This can reduce the pushing force of the paper discharged after the paper discharged earlier.
Therefore, it is difficult for the previous paper to be pushed out from the paper discharge tray.
As described above, according to the present invention, it is possible to discharge a small size sheet with little disturbance in posture, and it is possible to prevent a large size sheet from being pushed out of the discharge tray.

Embodiments of a paper discharge device of an image forming apparatus according to the present invention will be described below with reference to the drawings.
1A is a schematic front view showing an embodiment of a paper discharge device of an image forming apparatus according to the present invention, and FIG. 1B is a diagram showing only a pair of paper discharge rollers in FIG. 2 is a schematic front view showing a state when discharging a large-size sheet, FIG. 3 is a view showing a state when discharging a large-size sheet, and (a) is a partially enlarged view of FIG. ) Is a perspective view of the main part, FIG. 4 is a schematic front view showing a state when a small-size sheet is discharged, FIG. 5 is a view showing a state when a small-size sheet is discharged, and FIG. FIG. 4 is a partially enlarged view of FIG. 4, and FIG.

  As shown in these drawings (mainly FIG. 1 and FIG. 3), the paper discharge device 10 is provided in a paper discharge portion of the image forming device 3, and an image is formed by the image forming portion 3 a of the image forming device 3. The sheet discharge roller pair 20 discharges the sheet on which the sheet is formed toward the sheet discharge tray 11, and the sheet discharge roller pair 20 is in contact with the drive roller 21 and the driven roller 22 driven by the drive roller 21. It consists of and.

  As shown in FIG. 3, the drive roller 21 is composed of a shaft 21a rotatably supported by a frame (not shown) and four rubber rollers 21b fixed to the shaft 21a. The image forming apparatus is driven to rotate in the paper discharge direction (clockwise in FIG. 1) by being driven to rotate through the gear train G (see FIG. 6).

As shown by a solid line and a virtual line in FIG. 1, the driven roller 22 is configured to be rotatable around the shaft 21 a of the driving roller 21, and is configured to be capable of vertically changing the discharge direction with respect to the discharge tray 11. Yes. This will be described in detail below.
As shown in FIG. 3, the driven roller 22 is rotatably provided on the shaft 22a.
Both ends of the shaft 22a are supported by levers 23 (only one is shown in FIG. 3). The lever 23 is provided so as to be rotatable around the shaft 21 a of the driving roller 21, and one lever 23 is provided with a knob 23 a for operation. The other lever 23 (not shown) is not provided with this knob 23a.
Therefore, when the lever 23 is rotated about the axis 21 a of the drive roller 21, the driven roller 22 is rotated about the axis 21 a of the drive roller 21.
The driven roller 22 is a synthetic resin roller, is rotatably supported by the shaft 22a, and is pressed against the driving roller 21 by the elasticity of the shaft 22a so as to be in contact with the driving roller 21. (Nip part) is constituted, and is driven by the driving roller 21 to rotate.

Between the lever 23 and the frame 3f of the image forming apparatus, there is provided a restricting portion (not shown) for restricting the rotation range of the lever 23 with a click feeling. The user holds the lever 23 with the knob 23a, and the lever 23 is shown by a solid line in FIG. 2 and 3, when the lever 23 is rotated in the clockwise direction, the lever 23 is fixed to the first position with a click feeling by the restricting portion, so that the driven roller 22 also has a solid line in FIG. It is fixed at the first position shown in FIGS.
When the driven roller 22 is in the first position, the sheet discharge direction of the sheet with respect to the sheet discharge tray 11 by the contact portion (nip portion) N1 (see FIG. 3) between the drive roller 21 and the driven roller 22 is the upward direction F1. (See FIG. 2).

Further, when the user holds the knob 23a and rotates the lever 23 counterclockwise as shown in the phantom line of FIG. 1 and FIGS. 4 and 5, the lever 23 is clicked to the second position by the restricting portion. As a result, the driven roller 22 is also fixed at the phantom line in FIG. 1 and at the second position shown in FIGS.
When the driven roller 22 is in this second position, the paper discharge direction of the paper with respect to the paper discharge tray 11 by the contact portion (nip portion) N2 (see FIG. 5) between the drive roller 21 and the driven roller 22 is the above-described paper discharge. Compared to the direction F1, the downward direction F2 (see FIG. 4).

  In other words, as shown in FIG. 1B, the horizontal line passing through the rotation center of the drive roller 21 is H, the normal line at the nip portion N1 is N1 ′, the normal line at the nip portion N2 is N2 ′, and the horizontal line H And θ1> θ2, where θ1 is the angle formed by the normal line N1 ′ and θ1 is the angle formed by the horizontal line H2 and the normal line N2 ′.

The paper discharge device 10 of the image forming apparatus as described above includes a paper discharge roller pair 20 that discharges the paper on which an image is formed in the image forming unit toward the paper discharge tray 11. Is composed of a driving roller 21 and a driven roller 22 driven in contact with the driving roller 21, and the driven roller 22 is configured to be rotatable around the shaft 21 a of the driving roller 21. Since the paper discharge direction with respect to 11 is variable up and down, when the paper to be discharged is a small size, the driven roller 22 is rotated downward around the shaft 21a of the drive roller 21 to discharge the paper. By directing the paper discharge direction with respect to the tray 11 to the lower side F2, it is possible to discharge a small-sized sheet with less posture disturbance.
On the other hand, when the paper to be discharged is a large size, the driven roller 22 is rotated upward about the shaft 21a of the driving roller 21 so that the paper discharge direction with respect to the paper discharge tray 11 is directed upward F1. Thus, it is possible to reduce the pushing force of the sheet discharged on the sheet discharge tray 11 first with respect to the sheet discharged first.
Therefore, it is difficult for the previous paper to be pushed out from the paper discharge tray.
As described above, according to this embodiment, it is possible to discharge a small size sheet with little disturbance in posture, and it is possible to prevent a large size sheet from being pushed out from the discharge tray.

  Further, depending on the type of paper (for example, thickness), curling may become tight when the paper passes through the fixing roller pair 3b and is discharged onto the paper discharge tray 11. In such a case, Regardless of the paper size, it is possible to prevent the paper from curling on the paper discharge tray 11 by directing the paper discharge direction downward F2.

<Other embodiments>
6 and 7 are diagrams showing the main part of another embodiment, in which (a) is a front view and (b) is a perspective view.
FIG. 6 is a diagram illustrating a state in which a large-size sheet is discharged, and FIG. 7 is a diagram illustrating a state in which a small-size sheet is discharged.
This embodiment differs from the above-described embodiment in that the driven roller 22 is rotated around the shaft 21a of the driving roller 21 by a dedicated motor instead of the rotation operation of the lever 23 by the user. The other points are the same.

6 and 7, M is a dedicated motor, and this motor M is fixed to a frame (not shown).
Both ends of the shaft 22a of the driven roller 22 are supported by levers 24 (only one is shown in FIGS. 6 and 7). The lever 24 is provided so as to be rotatable around the shaft 21 a of the drive roller 21. A gear 24 g is fixed to one lever 24, and the gear 24 g meshes with the output gear Mg of the motor M. . The other lever 24 (not shown) is not provided with a gear 24g.
At both ends of the shaft 22a of the driven roller 22, a pair of frames 25 (only one is shown in FIGS. 6 and 7) are provided. The frame 25 is provided with an arc-shaped elongated hole 25a centering on the shaft 21a of the drive roller 21, and the shaft 22a of the driven roller 22 is inserted through the elongated hole 24a.

  Accordingly, when the output gear Mg of the motor M is rotated counterclockwise in FIG. 6 and the lever 24 is rotated clockwise around the shaft 21a of the driving roller 21, the driven roller 22 is driven within the range of the long hole 25a. The roller 21 rotates clockwise around the shaft 21a, and the driven roller 22 moves to the first position described above, and the sheet is discharged by the contact portion (nip portion) N1 between the driving roller 21 and the driven roller 22. The paper discharge direction with respect to the tray 11 is an upward direction F1.

  Further, as shown in FIG. 7, when the output gear Mg of the motor M is rotated clockwise and the lever 24 is rotated counterclockwise around the shaft 21a of the driving roller 21, it is driven within the range of the long hole 25a. The roller 22 rotates counterclockwise around the shaft 21a of the driving roller 21, and the driven roller 22 moves to the second position described above, so that the contact portion (nip portion) N2 between the driving roller 21 and the driven roller 22 is reached. The sheet discharge direction of the sheet with respect to the sheet discharge tray 11 is the downward direction F2.

The operation of the motor M as described above is controlled by a control unit (not shown) provided in the image forming apparatus.
That is, the control unit controls the motor M when the large-size sheet is selected by the user in the operation panel provided in the image forming apparatus or the printer driver incorporated in the personal computer to which the image forming apparatus is connected. The driven roller 22 is moved to the first position, and when the user selects a small size paper on the operation panel or printer driver, the motor M is operated as described above to drive the driven roller 22. Is moved to the second position.
Alternatively, the control unit normally moves the driven roller 22 to the first position, and after the paper detection sensor (for example, the sensor 3s in FIG. 1A) provided in the image forming apparatus is turned on until it is turned off. Is the time corresponding to the small size paper, the motor M is operated as described above to move the driven roller 22 to the second position.
According to this embodiment, in addition to the operational effects of the above-described embodiment, the effect that the first and second positions of the driven roller 22 are automatically selected is obtained.

The gear train G shown in FIGS. 6 and 7 also constitutes drive gear trains for the fixing roller pair 3b and the post-fixing roller pair 3c shown in FIG.
In FIG. 1, 3d is a secondary transfer belt on which a plurality of color toner images are superimposed, 3e is a secondary transfer roller, and 3h is to switch back a sheet of paper on which an image is formed on one side to form an image on the other side. A return path 3i for returning to the image forming unit 3a again is a return roller pair.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the gist of the present invention.
For example, in the above embodiment, the variable position of the driven roller 22 is the first and second positions, but may be three or more.
In the other embodiments, the motor M is used as the operating means for moving the position of the driven roller 22, but a solenoid may be used.

1A and 1B are diagrams illustrating an embodiment of a paper discharge device of an image forming apparatus according to the present invention, in which FIG. 1A is a schematic front view, and FIG. FIG. 3 is a schematic front view illustrating a state when discharging a large-sized sheet. FIG. 4 is a diagram illustrating a state in which large-size paper is discharged, in which (a) is a partially enlarged view of FIG. 2 and (b) is a perspective view of the main part. FIG. 3 is a schematic front view illustrating a state when a small-size sheet is discharged. FIG. 5 is a diagram illustrating a state where small-size paper is discharged, in which (a) is a partially enlarged view of FIG. 4 and (b) is a perspective view of the main part. 4A and 4B are diagrams illustrating a main part of another embodiment in the case of discharging a large size sheet, in which FIG. The figure which shows the principal part of other embodiment same as the above in the case of discharging small size paper, (a) is a front view, (b) is a perspective view. (A) (b) (c) is explanatory drawing of a subject.

Explanation of symbols

  3: image forming apparatus, 3a: image forming unit, 10: paper discharge device, 11 paper discharge tray, 20 paper discharge roller pair, 21: drive roller, 22: driven roller, 22b: driven roller located at the center, 22a : Driven rollers located on both outer sides, N1, N2: contact portion, F1, F2: paper discharge direction.

Claims (1)

A pair of paper discharge rollers for discharging the paper on which an image has been formed in the image forming unit to a paper discharge tray. The paper discharge roller pair is driven by a driving roller and a driven roller that is in contact with the driving roller. A paper discharge device of the image forming apparatus configured by
A paper discharge device for an image forming apparatus, wherein the driven roller is configured to be rotatable about an axis of the drive roller, and a paper discharge direction with respect to the paper discharge tray is variable up and down.

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