Sheet discharging device

Abstract

To achieve excellent discharged paper alignment of paper stacked on a paper discharge base without providing a large-scale mechanism for operating a paper discharge part to the right and left.SOLUTION: The paper discharge device is provided with a paper discharge conveyance part 4 for conveying and discharging the paper PA, a paper discharge table 51 on which the paper discharged by the paper discharge conveyance part 4 is stacked, a pair of wings 4a and 4b provided in the paper discharge conveyance part 4 for lifting both end parts in the width direction of the paper discharged by the paper discharge conveyance part 4 to curve the paper, a lifting mechanism 4 for independently lifting and lowering the pair of wings 4a and 4b, a suction fan 4 for sucking and conveying the paper under the paper discharge conveyance part 4, a paper sensor 4 for detecting the position of the paper in the width direction conveyed by the paper discharge conveyance part 4, and a control part 6 for controlling the lifting mechanism 4 and the suction fan 4 based on the detected position of the paper in the width direction conveyed by the paper discharge conveyance part 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a paper delivery device that achieves good alignment of paper sheets stacked on a paper delivery tray without providing a large-scale mechanism for moving a paper delivery section left and right. [Background technology]

[0002] 2. Description of the Related Art Paper delivery devices are known that are provided in printing devices and that deliver and stack printed sheets of paper. Paper delivery devices are required to align the delivered sheets well.

[0003] Patent document 1 discloses a technology relating to a paper discharge device that changes the angle of multiple jump ramps relative to each side edge of a paper sheet on which an image has been formed and / or the position at which the multiple jump ramps abut and guide each side edge of a paper sheet on which an image has been formed, depending on parameters that affect paper discharge alignment other than paper type, paper size, image formation speed, and ambient temperature and humidity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-297194 Summary of the Invention [Problem to be solved by the invention]

[0005] When paper is fed through a printing device, various factors can cause the center of the paper ejection wing and the center of the paper to become misaligned in the width direction of the paper as the paper is transported from feeding to ejection. When the paper is misaligned, the heights of the edges of the paper in the width direction differ, and when the paper is ejected in this state, the flying posture becomes unstable, causing problems such as poor paper alignment or the paper flying off the ejection tray.

[0006] The technology in Patent Document 1 only changes the left and right angles of the paper discharge wings, but does not change the starting point for changing the angle relative to the paper discharge center, making it difficult to properly align the paper discharge if the center position is shifted.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a paper discharge device that achieves good paper discharge alignment for papers stacked on the paper discharge tray without providing a large-scale mechanism that moves the paper discharge section left and right. [Means for solving the problem]

[0008] In order to achieve the above object, a first feature of the paper discharge device according to the present invention is: a paper discharge conveyance unit that conveys and discharges paper; a paper discharge tray on which the paper discharged by the paper discharge conveyance unit is stacked; a pair of wings provided in the discharge conveyance section, the wings lifting up both ends in the width direction of the paper discharged by the discharge conveyance section to curve the paper; a lifting mechanism that independently lifts and lowers each of the pair of wings; a suction conveying means provided below the paper discharge conveying section for suction conveying the paper; a detection unit for detecting a position in a width direction of the paper conveyed by the paper discharge conveyance unit; a control unit that controls the lifting mechanism and the suction conveying unit based on the detected position in the width direction of the paper conveyed by the paper discharge conveying unit; The reason is that it is equipped with the following. [Effects of the Invention]

[0009] According to the paper discharge device of the present invention, it is possible to achieve good alignment of paper sheets stacked on the paper discharge tray without providing a large-scale mechanism for moving the paper discharge unit left and right. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of an inkjet printing apparatus according to a first embodiment of the present invention. [Figure 2] 1 is a plan view of a paper discharge transport unit provided in an inkjet printing apparatus according to a first embodiment of the present invention. [Figure 3] 3 is an explanatory diagram illustrating the positional relationship between a wing of a paper discharge transport unit provided in the inkjet printing apparatus according to the first embodiment of the present invention and a paper sheet. FIG. [Figure 4] 1A and 1B are explanatory diagrams illustrating the operation of the inkjet printing device according to the first embodiment of the present invention, in which (a) shows a state in which paper is properly transported without misalignment, (b) shows a state in which misalignment occurs in the paper, and (c) shows a state in which the wings are raised and lowered by the lifting mechanism. [Figure 5] 10A and 10B are explanatory diagrams illustrating the operation of an inkjet printing device according to a second embodiment of the present invention, in which (a) shows a state in which paper is properly transported without misalignment, (b) shows a state in which misalignment occurs in the paper, and (c) shows a state in which the wing is raised and lowered by the lifting mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings. However, it should be noted that the drawings are schematic and may differ from the actual product. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0012] Furthermore, the embodiments shown below are merely examples of devices that embody the technical concept of the present invention, and the technical concept of the present invention does not limit the arrangement of each component to that shown below. Various modifications can be made to the technical concept of the present invention within the scope of the claims.

[0013] Example 1 An embodiment of an inkjet printing apparatus 1 to which an image forming apparatus according to the present invention is applied will be described in detail below with reference to the accompanying drawings.

[0014] FIG. 1 is a schematic diagram of an inkjet printing apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view of a paper discharge conveying section provided in the inkjet printing apparatus according to the first embodiment of the present invention, and FIG. 3 is an explanatory diagram illustrating the positional relationship between the wings of the paper discharge conveying section provided in the inkjet printing apparatus according to the first embodiment of the present invention and the paper.

[0015] In the following description, the front side of the paper in FIG. 1 where the user is positioned is referred to as the right side, and the back side of the paper is referred to as the left side. Also, in FIG. 1, the up and down directions as seen from the user are referred to as the up and down directions. The transport direction of the paper PA is referred to as the front and back directions. In the following description, upstream means the front direction, and downstream means the back direction.

[0016] As shown in FIG. 1, the inkjet printing apparatus 1 includes a paper feed unit 2, an image forming unit 3, a paper discharge unit 5, and a control unit 6.

[0017] The paper feed unit 2 picks up the paper PA stacked on a paper feed tray (not shown) one by one from the top, and feeds the paper to the image forming unit 3.

[0018] The image forming unit 3 forms an image by ejecting black (K), cyan (C), magenta (M), and yellow (Y) inks from the nozzles of the inkjet head while transporting the paper PA at a predetermined transport speed. The nozzles form a nozzle row arranged linearly in the left-right direction (main scanning direction).

[0019] The paper discharge unit 5 includes the paper discharge transport unit 4 and a paper discharge tray 51 .

[0020] The paper discharge conveyance unit 4 discharges the paper PA, which has been conveyed from the image forming unit 3 at a predetermined conveyance speed, onto a paper discharge tray 51. The paper discharge conveyance unit 4 has a conveyor belt 41, a pair of conveyor rollers 42, a suction fan 43, a wing 44, a lifting mechanism 45, and a paper sensor 46.

[0021] The conveyor belt 41 is an endless belt looped around a pair of conveyor rollers 42. The conveyor belt 41 has air intake holes, which are through holes for attracting and holding the paper sheets PA, formed at predetermined intervals along the conveying direction of the conveyor belt 41. The conveyor belt 41 attracts and holds the paper sheets PA on the conveyor belt 41 by a negative pressure (adsorption force) generated in the air intake holes by driving the suction fan 43.

[0022] 1 by the rotational drive of the pair of transport rollers 42. As a result, the transport belt 41 moves endlessly to transport the paper PA backward.

[0023] The wings 44 have a pair of wings 44a and 44b in the width direction (left and right direction) of the paper sheet PA being transported, and lift up both ends of the paper sheet PA in the paper width direction, curving the paper sheet PA into a U-shape. This gives stiffness to the paper sheet PA being transported by the transport belt 41, and the paper is discharged onto the paper discharge tray 51.

[0024] The lifting mechanism 45 lifts and lowers the pair of wings 44a and 44b independently.

[0025] The paper sensor 46 is provided on the upstream side (front side) of the wing 44. The paper sensor 46 is made up of a CIS (Contact Image Sensor) which is a line sensor, and detects the paper position in the left-right direction of the paper PA transported by the image forming unit 3.

[0026] The paper ejection tray 51 is configured to hold the paper PA conveyed by the paper ejection conveyance section 4.

[0027] An end fence 52 is provided on the paper receiving tray 51 so as to be slidable in the front-rear direction, and a side fence 53 is provided so as to be slidable in the left-right direction.

[0028] Here, as shown in Figure 3, during the process of transporting paper PA by the paper feed unit 2, image forming unit 3, and paper discharge unit 5, various factors may cause a positional shift, such as the center position C2 of paper PA2 (PA), relative to the center position C1 (the center position of wings 44a, 44b in the paper width direction (left and right direction)) of paper PA1 (PA) when it is transported properly.

[0029] If such a misalignment occurs, the height of the edges of the paper PA in the paper width direction (left and right direction) will differ, and if the paper is discharged in this state, the flying posture will become unstable, which may result in problems such as poor paper discharge alignment or the paper flying off the paper discharge tray 51.

[0030] Therefore, the control unit 6 controls the lifting mechanism 45 and the suction fan 43 based on the position in the width direction of the paper PA conveyed by the paper discharge conveyance unit 4, which is detected by the paper sensor .

[0031] 4A and 4B are explanatory diagrams illustrating the operation of the inkjet printing apparatus 1 according to the first embodiment of the present invention. (a) is a diagram illustrating a state in which the paper PA is properly conveyed without misalignment, (b) is a diagram illustrating a state in which the paper PA is misaligned, and (c) is a diagram illustrating a state in which the wings 44a and 44b are raised and lowered by the lifting mechanism 45.

[0032] As shown in Figure 4(a), when the paper PA is transported properly without misalignment, the height d1 of the left and right ends of the paper PA in the paper width direction (left and right direction) becomes the same, and the flying posture of the paper PA becomes stable, resulting in good paper alignment on the paper output tray 51.

[0033] 4(b), if the sheet PA is misaligned, the heights of the left and right edges of the sheet PA in the sheet width direction (left-right direction) will be different. Specifically, the height of the edge of the sheet PA on the wing 44a side (left side) will be d21, and the height of the edge of the sheet PA on the wing 44b side (right side) will be d22, and d21 and d22 are different heights. If the sheet PA is discharged in this state, the flight posture of the sheet PA may become unstable, resulting in poor sheet alignment or the sheet PA flying off the sheet discharge tray 51.

[0034] 4(c), the control unit 6 controls the lifting mechanism 45 to raise and lower the wings 44a and 44b so that the heights of the left and right ends in the width direction of the sheet of paper PA are the same, based on the position in the width direction of the sheet of paper PA conveyed by the sheet discharge conveyance unit 4 detected by the sheet sensor 46. Here, the control unit 6 controls the lifting mechanism 45 to raise and lower the wing 44a and lower the wing 44b. As a result, the height d3 of the left and right ends in the width direction of the sheet of paper PA is the same, so when the sheet of paper PA is discharged by the sheet discharge conveyance unit 4, the flying posture of the sheet of paper PA is stable, and good sheet alignment can be achieved on the sheet discharge tray 51.

[0035] Furthermore, if the sheet PA is significantly deviated from its center position C1 when properly transported, it is necessary to significantly raise and lower the wings 44a, 44b using the lifting mechanism 45. When there is a difference in height between the wings 44a, 44b, the sheet PA experiences greater resistance on the side with the higher wing height when the sheet PA forms a U-shape as it is discharged, and the difference in resistance between the left and right sides of the sheet PA may cause the sheet PA to skew.

[0036] Therefore, based on the detection result of the paper sensor 46, if the paper PA being transported is significantly deviated from the center position C1 that would be obtained if the paper PA were transported properly, the control unit 6 controls the suction fan 43 to increase the suction air to firmly hold the paper PA without causing it to skew.

[0037] The reason why the suction airflow from suction fan 43 is not kept strong all the time is to avoid increasing power consumption and noise, and the airflow volume is increased only when necessary. Therefore, if the transported sheet PA is significantly deviated from the center position C1 that would be achieved if the sheet PA were transported properly, control unit 6 controls the suction airflow from suction fan 43 to be strong so that the sheet PA is held firmly without skewing.

[0038] Furthermore, if the paper PA is thin paper, there is a concern that strong suction may cause wrinkles or paper ejection problems due to wrinkles if the paper PA has contact resistance, so the control conditions of the control unit 6 may be divided into tables according to the paper type to provide appropriate suction air.

[0039] The control unit 6 may also change the height of the edge of the discharged paper PA by moving the left and right independent wings 44a, 44b to obtain parameters suitable for paper discharge based on pre-printing information such as image ratio, paper type, paper size, image formation speed, and environmental temperature and humidity.Even during printing, feedback control of the height of the left and right wings 44a, 44b and the paper discharge suction air volume by the suction fan 43 can be performed according to the paper edge position detected by the paper sensor 46, thereby continuously preventing the paper from flying off the paper discharge tray 51 and further improving the alignment of the discharged paper.

[0040] <Example 2> In Example 1, a paper sensor 46, which is a line sensor CIS (Contact Image Sensor), is used to output a signal to detect the paper position in the left-right direction (main scanning direction) of the paper PA transported by the image forming unit 3, but this is not limited to this.

[0041] In the second embodiment, a sheet sensor 47, which is a reflective sensor, is used to output a signal for detecting the position of the sheet PA conveyed by the image forming unit 3 in the left-right direction (main scanning direction).

[0042] 5A and 5B are explanatory diagrams illustrating the operation of the inkjet printing apparatus 1 according to the second embodiment of the present invention. (a) is a diagram illustrating a state in which the paper PA is properly conveyed without misalignment, (b) is a diagram illustrating a state in which the paper PA is misaligned, and (c) is a diagram illustrating a state in which the wings 44a and 44b are raised and lowered by the lifting mechanism 45.

[0043] As shown in Fig. 5(a), the paper sensor 47 is a reflective sensor and is provided above the conveyor belt 41. The paper sensor 47 emits detection light in the width direction (left-right direction) of the paper PA and detects the paper position in the left-right direction of the paper PA by receiving the reflected light.

[0044] As shown in Figure 5(a), when the paper PA is transported properly without misalignment, the end height d1 of the paper PA in the paper width direction (left and right direction) becomes the same, and the flying posture of the paper PA becomes stable, so that good paper alignment can be achieved on the paper output tray 51.

[0045] 5(b), if the detection result of paper sensor 47 indicates that the sheet PA is misaligned, the heights of the edges of the sheet PA in the sheet width direction (left-right direction) will differ. Specifically, the height of the edge of the sheet PA on the wing 44a side (left side) will be d21, and the height of the edge of the sheet PA on the wing 44b side (right side) will be d22, and d21 and d22 are different heights. If the sheet PA is discharged in this state, the flight posture of the sheet PA may become unstable, resulting in poor sheet alignment or the sheet PA flying off the sheet discharge tray 51.

[0046] 5(c), the control unit 6 controls the lifting mechanism 45 to raise and lower the wings 44a and 44b so that the heights of the widthwise ends of the sheet of paper PA are the same, based on the widthwise position of the sheet of paper PA being conveyed by the sheet discharge conveyance unit 4 detected by the sheet sensor 47. Here, the control unit 6 controls the lifting mechanism 45 to raise and lower the wing 44a and lower the wing 44b. As a result, the height d3 of the widthwise ends of the sheet of paper PA is the same on the left and right, so that when the sheet of paper PA is discharged by the sheet discharge conveyance unit 4, the flying posture of the sheet of paper PA is stable, and good sheet alignment can be achieved on the sheet discharge tray 51.

[0047] In the first and second embodiments of the present invention, an embodiment of an inkjet printing device 1 to which the image forming device according to the present invention is applied has been described in detail, but the image forming device is not limited to this, and it goes without saying that the image forming device can be applied to various types of printing devices such as laser printers and stencil printing devices. (Addendum)

[0048] The present application discloses the following inventions.

[0049] (Appendix 1) a paper discharge conveyance unit that conveys and discharges paper; a paper discharge tray on which the paper discharged by the paper discharge conveyance unit is stacked; a pair of wings provided in the discharge conveyance section, the wings lifting up both ends in the width direction of the paper discharged by the discharge conveyance section to curve the paper; a lifting mechanism that independently lifts and lowers each of the pair of wings; a suction conveying means provided below the paper discharge conveying section for suction conveying the paper; a detection unit for detecting a position in a width direction of the paper conveyed by the paper discharge conveyance unit; a control unit that controls the lifting mechanism and the suction conveying unit based on the detected position in the width direction of the paper conveyed by the paper discharge conveying unit; A paper discharge device comprising:

[0050] This makes the height of the left and right edges of the paper in the width direction the same, so when the paper is discharged by the paper discharge transport unit, the paper's flight posture is stable, and good paper discharge alignment can be achieved on the paper discharge tray. Therefore, good paper discharge alignment can be achieved for the paper stacked on the paper discharge tray without providing a large-scale mechanism that moves the paper discharge unit left and right. [Explanation of symbols]

[0051] 1. Inkjet printing device 2 Paper feed section 3 Image forming unit 4 Paper ejection transport section 5 Paper output section 6 Control Unit 41 Conveyor belt 42 Conveyor roller 43 Suction fan 44 Wing 44a Wing 44b Wing 45 Lifting mechanism 46 Paper sensor 47 Paper sensor 51 Paper receiving tray 52 End Fence 53 Side Fence

Claims

[Claim 1] a paper discharge conveyance unit that conveys and discharges paper; a paper discharge tray on which the paper discharged by the paper discharge conveyance unit is stacked; a pair of wings provided in the discharge conveyance section, the wings lifting up both ends in the width direction of the paper discharged by the discharge conveyance section to curve the paper; a lifting mechanism that independently lifts and lowers each of the pair of wings; a suction conveying means provided below the paper discharge conveying section for suction conveying the paper; a detection unit for detecting a position in a width direction of the paper conveyed by the paper discharge conveyance unit; a control unit that controls the lifting mechanism and the suction conveying unit based on the detected position in the width direction of the paper conveyed by the paper discharge conveying unit; A paper discharge device comprising:

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