Post-processing device and image forming device equipped with the same

Abstract

To provide a post-processing device capable of improving stacking performance regardless of paper size.SOLUTION: A post-processing device 12 provided in an image forming device has a first paper discharge port 13, and the first paper discharge port 13 is provided with two pairs of paper discharge rollers including a discharge roller 28b and a pressure roller 30b, and a discharge roller 28c and a pressure roller 30c, and includes speed change means for changing the speed of the paper discharge roller pairs depending on the size of a paper, and swing means for swinging a vertical surface 20 in a height direction of the paper discharge roller pairs and the paper discharge tray on which the paper is stacked.SELECTED DRAWING: Figure 5B

Description

Technical Field

[0001] The present disclosure relates to a post-processing device and an image forming apparatus including the same.

Background Art

[0002] Conventionally, there has been provided a post-processing device provided in an image forming apparatus that improves the sheet alignment property (stacking property) by providing a swingable member on a paper discharge tray and changing the shape of the paper discharge tray so as to displace the stacked sheet position. For example, it is disclosed in Japanese Patent Application Laid-Open No. 2008-105782.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional post-processing devices provided in image forming apparatuses for improving the sheet alignment property were configured as described above. On the other hand, there is also provided a post-processing device that detects a high-humidity environment with a temperature and humidity sensor and controls to make the landing position of the sheet discharged onto the paper discharge tray farther than the normal speed of the paper discharge roller according to the environmental correction corresponding value. Such a post-processing device discharges the paper at a paper discharge speed as shown in Table 1 according to the environment.

[0005]

Table 1

[0006] However, depending on the size and brand of the paper, there has been a problem that the paper jumps out in the transport direction from the paper discharge tray.

[0007] The present disclosure has been made to solve the above-described problems, and an object thereof is to provide a post-processing device provided in an image forming apparatus that can improve the stacking performance (loadability) of sheets regardless of the size of the sheets, and an image forming apparatus having the same. **Means for Solving the Problems**

[0008] The post-processing device provided in the image forming apparatus according to the present disclosure has a sheet discharge port for discharging sheets, and a pair of discharge rollers and a discharge tray for stacking sheets are provided at the sheet discharge port. The post-processing device includes speed changing means for changing the speed of the pair of discharge rollers according to the size of the sheet, the pair of discharge rollers, and swinging means for swinging a vertical surface provided in the height direction of the discharge tray.

[0009] Preferably, the swinging operation of the swinging means is interlocked with the rotational drive of the pair of discharge rollers.

[0010] More preferably, the swinging means includes a cam and a spring that swing the vertical surface in the left-right direction.

[0011] The swinging means may further include a power transmission mechanism that converts a plurality of rotations of the pair of discharge rollers into one rotation of the cam.

[0012] In another aspect of the present disclosure, the image forming apparatus includes a control unit that controls speed changing means for changing the speed of the pair of discharge rollers according to the size of the sheet, and the above-described post-processing device. **Advantages of the Invention**

[0013] According to the present disclosure, at the sheet discharge port of the post-processing device provided in the image forming apparatus, there are provided speed changing means for changing the speed of the pair of discharge rollers according to the size of the sheet, the pair of discharge rollers, and swinging means for swinging a vertical surface provided in the height direction of the discharge tray. Since the speed of the pair of discharge rollers is changed according to the size of the sheet, the sheet is discharged onto the discharge tray at a speed corresponding to the size of the sheet, and since the vertical surface is swung by the swinging means, the sheet is properly stacked.

[0014] As a result, it is possible to provide a post-processing device provided in an image forming apparatus that can improve the stacking performance of sheets regardless of the size of the sheets.

[0015] The above object, other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments with reference to the drawings.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a front view showing an image forming apparatus according to an embodiment of the present disclosure and a post-processing apparatus provided in the image forming apparatus. Referring to FIG. 1, in the present disclosure, a post-processing apparatus 12 as a post-processing apparatus is provided on the left side of the image forming apparatus 10. The image forming apparatus 10 includes an apparatus main body 51, an image forming unit (not shown) provided in the apparatus main body 51, paper feed cassettes 52a to 52d that supply sheets of different sizes to the image forming unit, and an image reading device 53 provided above the apparatus main body 51. Here, for example, A4-sized paper is accommodated in the paper feed cassette 52a, A3-sized paper is accommodated in the paper feed cassette 52b, A5-sized paper is accommodated in the paper feed cassette 52c, and B5-sized paper is accommodated in the paper feed cassette 52d.

[0018] The post-processing apparatus 12 is provided with two paper discharge ports, a first paper discharge port 13 and a second paper discharge port 14.

[0019] FIG. 2 is a perspective view showing the first paper discharge port 13 provided in the post-processing apparatus 12. FIG. 3 is a side view showing the first paper discharge port 13 and the second paper discharge port 14 (see FIG. 1) provided in the post-processing apparatus 12, and the configuration of a conveyance portion that conveys paper to each of the paper discharge ports 13 and 14. FIG. 4 is a view showing a portion indicated by arrow 4-4 in FIG. 3.

[0020] The paper on which an image is formed by the image forming apparatus 10 is sent to the post-processing apparatus 12 provided on the left side of the image forming apparatus 10, and perforation, stapling, etc. of the paper are performed. Here, the post-processing apparatus 12 is provided with two paper discharge ports, a first paper discharge port 13 and a second paper discharge port 14, and paper is discharged and stacked at each of them. Here, the first discharge tray 16 of the first paper discharge port 13 will be specifically described, but the second discharge tray 18 of the second paper discharge port 14 is basically the same.

[0021] Referring to FIGS. 3 and 4, the paper on which an image is formed is conveyed to and stacked on the first paper discharge tray 16 through two sets of paper discharge roller pairs, which are composed of four paper discharge rollers 28a to 28d, the paper discharge rollers 28b and 28c arranged in the center, and the pressing rollers 30b and 30c provided on the paper discharge rollers 28b and 28c. Note that, at the right end of the first paper discharge tray 16 shown in FIG. 3, a vertical surface 20 for stacking paper is provided, and at the back of the vertical surface 20, a full paper detection sensor 24 for detecting that the first paper discharge tray 16 is full of stacked paper is provided. In addition, cams 32 are provided near the paper discharge rollers 28a and 28d, which will be described later.

[0022] Next, the paper discharge speed based on an environmental sensor (not shown) in this embodiment will be described. Table 2 is a table showing the paper discharge speed for each paper size in this embodiment, corresponding to the conventional Table 1. As shown in Table 2, an appropriate paper discharge speed is determined for each paper size. A control unit (not shown) of the image forming apparatus determines the paper discharge speed shown in Table 2 based on the environmental sensor and instructs the post-processing apparatus 12 of the paper discharge speed.

[0023]

Table 2

[0024] Here, the large size refers to the case where the paper size is A3, the medium size refers to the case where the paper size is A4, and the small size refers to the case where the paper size is A5 or B5.

[0025] As shown in FIG. 4, both ends in the width direction of the first paper discharge tray 16 are surrounded by frames 40a and 40b, and the paper 27 on which an image is formed is conveyed as a paper passing width 44 at the central portion. The vertical surface 20 is provided so as to cover a range wider than the paper passing width 44, and the four paper discharge rollers 28a to 28d provided at the central portion are attached to a single shaft 29, and the shaft 29 is rotated by being driven by a motor 36 via a gear 38.

[0026] At this time, the gear 38 operates as a speed changing means to change the speed of the paper discharge roller pair composed of the paper discharge rollers 28b and 28c and the pressing rollers 30b and 30c that contact them according to the paper size as shown in Table 2.

[0027] That is, the paper discharge rollers 28b and 28c and the pressing rollers 30b and 30c that contact them constitute two paper discharge roller pairs. The pressing rollers 30b and 30c are supported by a common shaft 31.

[0028] FIG. 4 also shows the full - cup detection sensor 24 (see FIG. 3), the detection holes 21 provided at the center of the vertical surface 20, and the cams 32a and 32b provided at both ends of the shaft 29 and rotated by the rotation of the shaft 29. Further, the outer surfaces 42a and 42b of the post - processing device 12 are connected to the extension portions of the frames 40a and 40b.

[0029] Next, the configuration in the direction intersecting the vertical surface 20 shown in FIG. 4 will be described. FIG. 5A is a cross - sectional view in the vicinity of the direction intersecting the vertical surface 20 at the center of the first paper discharge tray 16 shown in FIG. 4, and FIG. 5B is a view showing the state in which the paper 27 is loaded in FIG. 5A. In FIGS. 5A and 5B, only one of the paper discharge roller pairs (the paper discharge roller 28b and the pressing roller 30b) is shown, and since the cams 32a and 32b have the same movement, they are shown as cam 32.

[0030] Referring to FIGS. 5A and 5B, the vertical surface 20 is provided near the lowermost end of the inclined portion of the first paper discharge tray 16 such that the lower portion of the vertical surface 20 is rotatable about the rotation shaft 22. The paper 27 is loaded by the inclined portion of the first paper discharge tray 16 and the vertical surface 20. The vertical surface 20 is supported from the right side by springs 26a and 26b (see FIG. 4), and is configured to swing by a cam 32 provided coaxially with the paper discharge rollers 28a to 28d.

[0031] FIG. 5B is a diagram showing a state in which the rear ends of a plurality of sheets 27 discharged onto the first paper discharge tray 16 are caught by the vertical surface 20, and a part of the sheets 27 is stacked without landing on the first paper discharge tray 16, so that the rear ends of the plurality of sheets 27 are curled. When the plurality of sheets 27 are stacked in a curled state like this, a problem occurs in that the full-sheet detection sensor 24 (see FIG. 5A) operates even though there are few sheets 27.

[0032] [First Embodiment] Therefore, in this embodiment, in order not to be in such a state, the vertical surface 20 is swung in the left-right direction as shown by the solid line and the dotted line indicated by the arrow in the figure by the cam 32 and the spring 26 (26a in FIG. 5A) to prevent the stacking of the curled portions of the sheets 27. In this way, the cam 32 and the spring 26 operate as swinging means for swinging the vertical surface 20 in the height direction of the first paper discharge tray 16. Here, the swinging range is set to 2 mm.

[0033] Next, the cam 32 will be described. FIG. 6 is a diagram showing the movement of the vertical surface 20 swung by the rotation of the cam 32. As shown in FIGS. 4 and 6, the cams 32a and 32b are provided at both end portions of the shaft 29 that is rotationally driven by the motor 36 via the gear 38.

[0034] [Second Embodiment] As shown in FIG. 6, the vertical surface 20 swings from the left side to the right side in order. Here, the shape of the shaft 29 to which the cam 32 is attached and the shape of the hole attached to the shaft 29 of the cam 32 are indicated by circles, but the actual shapes will be described later. Also, here, the positional relationship between the shaft 29 and the hole attached to the shaft 29 of the cam 32 is also shown schematically, and the springs 26a and 26b (see FIG. 5A) provided on the back surface of the vertical surface 20 are also omitted from the illustration.

[0035] First, referring to the leftmost figure, when the vertical surface 20 is not in contact with the cam 32, the vertical surface 20 stands upright in the upward direction of the rotation axis 22. Next, as shown in the right figure, the cam 32 rotates to the left around the axis 29. Along with this, the vertical surface 20 is pushed by the cam 32 and tilts to the right. Next, as shown in the third figure from the left, the cam 32 rotates to the lowest position. Along with this, the vertical surface 20 is further pushed by the cam 32 and tilts to the far right. Next, as shown in the fourth figure from the left, the cam 32 rotates upward and to the right. Along with this, the vertical surface 20 moves away from the cam 32 and returns slightly to the left. Next, as shown in the rightmost figure, the cam 32 returns to the state shown at the left end where the initial vertical surface 20 stands upright in the upward direction.

[0036] As described above, the rocking motion of the paper discharge roller pair (the paper discharge rollers 28b, 28c and the pressing rollers 30b, 30c in contact therewith, see FIG. 4) and the vertical surface 20 is linked to the rotational drive of the paper discharge roller pair.

[0037] In the embodiment of FIG. 6, in order to make the rocking motion easier to understand, a form is shown in which every time the roller 30b makes one rotation, the cam 32 that shares the roller 28 and the axis 29 also makes one rotation. However, since the vertical surface 20 makes one round trip with one rotation of the roller 28, it may cause vibrations in the post-processing device and factors that cause noise associated with the vibrations. The rocking of the vertical surface 20 may occur every time a plurality of sheets of paper 27 are stacked. For example, the rocking period may be one round trip every 30 seconds. In this case, the cam 32 may not share the roller 28 and the axis 29, and may be configured to pass through a gear having a ratio that makes the cam 32 make one rotation for a plurality of rotations of the axis 29. Also, the gear may be a power transmission mechanism composed of a plurality of gears.

[0038] FIG. 7 is a diagram showing the shape of the cam 32. In order to enable the rocking of the vertical surface 20 as shown in FIG. 6, the cam 32 has an eccentric D-cut hole 34 as shown in FIG. 7, and it is attached to a predetermined position of the axis 29. Here, the cam 32 is circular with a diameter of 20 mm, and the D-cut hole 34 is provided at a position shifted 2 mm from the center of a 20-mm diameter circle.

[0039] In FIGS. 5A to 5B and FIG. 6, although the shapes of the shaft 29 and the like are all indicated by circles, the portion of the shaft 29 where the cams 32a and 32b are provided is D-shaped so that the D-cut hole 34 can be inserted.

[0040] In the above embodiment, the case where two pairs of paper discharge rollers composed of a pair of a paper discharge roller and a pressing roller are provided has been described. However, the present invention is not limited to this, and pressing rollers may be provided for all four paper discharge rollers, and all the paper discharge rollers may be used as a pair of paper discharge rollers.

[0041] The present disclosure can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely examples and should not be construed in a limited manner. Modifications and changes belonging to the equivalent scope of the claims of the present disclosure are all within the scope of the present disclosure.

Industrial Applicability

[0042] According to the present disclosure, since it is possible to provide a post-processing device provided in an image forming apparatus that can improve the stacking performance of sheets regardless of the size of the sheets, it is useful as a post-processing device provided in an image forming apparatus.

Explanation of Reference Numerals

[0043] 10 Image forming apparatus 12 Post-processing device 13 First paper discharge port 14 Second paper discharge port 16 First paper discharge tray 18 Second paper discharge tray 20 Vertical surface 21 Detection hole 22 Rotation shaft 24 Full detection sensor 26a, 26b Spring 27 Sheet 28a to 28d Paper discharge roller 29, 31 Shaft 30b, 30c Pressing roller 32a, 32b Cam 34 D-cut hole 36 Motor 38 Gear 40a, 40b Frame 42a, 42b Exterior surface 44 Paper feed width 51 Apparatus main body 52a~52d Paper feed cassette 53 Image reading device

Claims

1. having a paper discharge port for discharging paper, wherein the paper discharge port is provided with a pair of discharge rollers and a paper discharge tray for stacking the paper, speed changing means for changing the speed of the pair of discharge rollers according to the size of the paper, and a post-processing device provided in an image forming apparatus, the post-processing device including the pair of discharge rollers and swinging means for swinging a vertical surface provided in the height direction of the paper discharge tray.

2. The post-processing device provided in the image forming apparatus according to claim 1, wherein the swinging operation of the swinging means is interlocked with the rotational drive of the pair of discharge rollers.

3. The post-processing device provided in the image forming apparatus according to claim 1, wherein the swinging means includes a cam and a spring for swinging the vertical surface in the left-right direction.

4. The post-processing device provided in the image forming apparatus according to claim 3, wherein the swinging means further includes a power transmission mechanism for converting a plurality of rotations of the pair of discharge rollers into one rotation of the cam.

5. An image forming apparatus comprising: a control unit that controls speed changing means for changing the speed of a pair of discharge rollers according to the size of the paper; and the post-processing device according to any one of claims 1 to 4.

Images