JP4027260B2 - Paper discharge device, image forming device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper discharge device including a paper discharge sensor that detects a paper discharge state when a paper is discharged from the inside of the image forming device to a paper receiving portion outside the device, and an image forming device including the paper discharge device. is there.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in an image forming apparatus such as a front access type copying machine that reduces the area occupied by the apparatus, a printing paper feeding unit disposed at the lower part of the apparatus, and a document reading unit disposed at the upper part of the apparatus, A type has been developed in which the printed paper is discharged to a paper receiving portion (paper discharge portion) disposed between the two. In such an image forming apparatus, the sheet stacking height of the sheet receiving unit is greatly limited, and the number of sheets that can be discharged is relatively small.
For this reason, the paper discharge device provided in such an image forming apparatus is provided with a paper discharge sensor in the vicinity of the paper discharge port, thereby detecting the completion of paper discharge or the number of paper discharged to the paper receiving portion. The function to detect the paper discharge (stacking) state on the paper receiving part by notifying the user and notifying the user when the paper receiving part is full (upper limit stack number) is provided. It has been.
5A and 5B are schematic cross-sectional views of a conventional paper discharge device A, FIG. 5A shows a state after completion of paper discharge, and FIG. 5B shows a state during paper discharge.
A conventional paper discharge device A includes a pair of upper and lower paper discharge rollers 41 (a paper discharge driven roller 41b and a paper discharge drive roller 41a) that are paper discharge means for discharging paper from the image forming apparatus to a paper receiving portion outside the apparatus. , A displacement lever 51 (displacement member) that displaces (rotates) by contact with the paper being discharged, and a photosensor 52 that detects a displacement state (rotation state) of the displacement lever 51.
The displacement lever 51 is positioned at a position P0 (hereinafter referred to as a reference position) shown in FIG. 5A due to its own weight in a normal state (a state where the paper S is not being discharged), and the paper S by the paper discharge roller 41. During the sheet discharge, the sheet is displaced by contacting the sheet S being discharged as shown in FIG. By detecting the displacement state of the displacement lever 51 at this time by the photo sensor 52, it is detected that the sheet S is being discharged and the discharge of the sheet has been completed (the displacement lever 51 and the above-mentioned displacement sensor 51). The photo sensor 52 constitutes a paper discharge sensor).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 02-270762
[Problems to be solved by the invention]
However, in the image forming apparatus of the type described above, the sheet is moved along a substantially U-shaped curved conveyance path which is discharged in a substantially horizontal direction after being directed substantially vertically upward from a substantially horizontal state in the sheet feeding unit. Since the paper is conveyed, it is often discharged in a curled state (curved state). In particular, when the water content of the paper is large, curling is more likely to occur because the amount of evaporated water on the image surface side is large when the image on the paper is heated and fixed.
When the paper is discharged in a curled state in this way, as shown in FIG. 6A, the curled portion of the paper after completion of paper discharge is brought into contact with the displacement lever 51 (displacement member) to be displaced (push up). Therefore, there is a problem in that the completion of paper discharge cannot be detected and it is erroneously detected that a paper jam (JAM) has occurred. Further, as shown in FIG. 6B, the curled portion of the paper comes into contact with the lower paper discharge roller (in the example shown in FIG. 6, the paper discharge roller 52a), and the discharged paper is caught in the apparatus. There was also a problem of being.
On the other hand, in Patent Document 1, when curled paper is discharged to a paper discharge tray (paper receiving portion), the curled portion of the paper pushes up (in contact with) the detection lever, and the paper to the paper discharge tray. A discharge overflow detection method for preventing erroneous detection of a full sheet before the number of stacked sheets reaches a predetermined set number is shown.
However, the detection lever for detecting the height of the paper stacked on the paper receiving portion is a relatively large member, and such a paper full (overflow) detection means is provided along with the paper discharge sensor. In an image forming apparatus that is required to be downsized, there is a problem that it cannot be adopted in terms of space.
Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an output for detecting a discharged state even when curled paper is discharged to a paper receiving portion. Provided are a paper discharge device that prevents a paper discharge sensor from erroneously detecting contact with a paper sensor and that a discharged paper is caught in the device by a paper discharge roller, and an image forming apparatus including the paper discharge device. There is.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a pair of upper and lower discharge rollers for discharging a sheet from the image forming apparatus to a sheet receiving section outside the apparatus, and a nip portion between the discharged sheet and the discharge roller pair. A paper discharge sensor that detects a paper discharge state based on a displacement state of a displacement member that is displaced by contact at a position after passing; a discharge device that is below a nip portion of the discharge roller pair. A convex curved surface is formed in the direction of the paper receiving portion and a notch portion is formed through which the displacing displacement member is passed. And a cover member that blocks the sheet discharged to the sheet receiving portion from coming into contact with the displacement member and the lower roller. What is done A.
Thus, even when the curled paper is discharged, it is possible to prevent the curled portion (paper trailing edge) of the paper from coming into contact with the displacement member and displacing it, and the paper discharge sensor Detection (malfunction) can be prevented.
[0006]
Further, the cover member is, the provided below the nip of the discharge roller pair, the one in which the curved surface of the projection in the direction of the paper receiving portion is formed, the cover member is a discharge of the paper In addition, the rear end portion of the discharged paper (the end portion on the downstream side in the discharge direction) slides smoothly on the curved surface and falls onto the paper receiving portion.
[0007]
Also, before Symbol cover member, the so sheet to receiver sheet discharge by the paper intercepts also be in contact with the lower roller of the discharge roller pair, the sheet after sheet ejection device by the lower roller It can prevent being caught in.
Further, the cover member, the one in which notches for passing the displacement member which is displaced is formed in one (integral) said cover member, in a predetermined range across the displacement direction on both sides of the displacement member The contact of the sheet with the displacement member can be blocked.
Further, the present invention may be an image forming apparatus provided with the paper discharge device.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus including a paper discharge device X according to an embodiment of the present invention. FIG. 2 is a perspective view of the paper discharge device X according to the embodiment of the present invention. FIG. 3 is a perspective view showing a structure in which a cover member constituting the paper discharge device X according to the embodiment of the present invention is attached to and detached from the shaft of the paper discharge roller, and FIG. 4 is a paper discharge device according to the embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a conventional paper discharge device A, and FIG. 6 is a cross-sectional view showing a state when curled paper is discharged by the conventional paper discharge device A.
[0009]
First, the image forming apparatus 1 including the paper discharge device X according to the embodiment of the present invention will be described using the cross-sectional view of FIG.
The image forming apparatus 1 has a copier mode (copying mode), a printer mode, and a FAX mode as print modes. An operation input from an operation unit (not shown) or a print job from an external host device such as a personal computer. Is selected by a control unit (not shown).
As shown in FIG. 1, the image forming apparatus 1 is roughly divided into a document reading unit 10 (document reading unit), a paper feeding unit 20 (paper feeding unit), a printing unit 30 (printing unit), and a paper discharge unit 40. The document reading unit 10 is disposed above the paper feeding unit 20, and the paper discharge unit 40 is disposed at an intermediate portion between the document reading unit 10 and the paper feeding unit 20.
Hereinafter, the copier mode will be described from the above processing modes.
After the original is placed on the platen glass 11 of the original reading unit 10 (scanner unit), the user mounts the paper in the paper feeding cassette 21 of the paper feeding unit 20 and is arranged on the front surface of the exterior of the apparatus. After inputting the condition input keys (not shown) (number of printed sheets / printing magnification, etc.), the copy operation is started when the start key on the operation panel is operated.
When the start key is operated, a main drive motor (not shown) starts and each drive gear rotates. Thereafter, the paper feed roller 22 rotates to feed the paper, and the fed paper reaches the registration roller 31. The registration roller 31 temporarily stops the paper so as to synchronize with the leading edge (image formation start portion) of the image formed on the photosensitive drum 32, and the leading edge of the paper is uniformly pressed against the registration roller 31. Thus, the leading edge position of the paper is corrected.
On the other hand, in the document reading unit 10, the copy lamp 12a (light source) is turned on, and the exposure starts when the copy lamp unit 12 moves in the direction of the arrow. Irradiation light applied to the document by the copy lamp 12a becomes reflected light (reflected light from the document) including image information of the document, and the reflected light is transmitted from the first mirror 12b provided in the copy lamp unit 12 to the second light. Reading is performed by inputting to the CCD 16 from the mirror 13, the third mirror 14, and the optical lens 15.
The image information read in this way is converted into an electrical signal by a CCD circuit provided in a control unit (not shown), and the image information signal is subjected to image processing under a set condition. , And sent to the LSU unit 33 as print data.
On the other hand, the entire photosensitive drum 32 is charged to a predetermined charging potential by the charging unit 34. Laser light from the LSU unit 33 is irradiated to the photosensitive drum 32 through a polygon mirror and various lenses (not shown), and an electrostatic latent image is formed on the photosensitive drum 32. Thereafter, the toner on the MG roller 35 s in the developing tank 35 is attracted onto the surface of the photosensitive drum 32, and the electrostatic latent image is visualized by the toner according to the potential gap on the photosensitive drum 32.
In addition, paper (sheet material) to be imaged is conveyed in the direction of the photosensitive drum 32 by the registration roller 31 in time, and the toner on the photosensitive drum 32 is transferred to the paper by the transfer unit 36 (corona charger). Is done. The toner remaining on the photosensitive drum 32 is scraped off by the cleaning blade 37 a of the drum unit and collected by the cleaner unit 37.
On the other hand, the paper on which the toner has been transferred passes through the upper heat roller 38a and the lower heat roller 38b of the fixing device 38 (fixing process), and heat and pressure are applied, so that the unfixed toner on the paper is melted into the paper. Affixed and discharged to a discharge tray 42 by a discharge roller 41 constituting the discharge device X.
[0010]
FIG. 2 is a perspective view illustrating the configuration of the paper discharge device X. FIG.
The paper discharge device X according to the embodiment of the present invention, like the conventional paper discharge device A (see FIG. 5), discharges paper from the image forming apparatus 1 to a paper discharge tray 42 (paper receiving portion) outside the device. A pair of upper and lower paper discharge rollers 41 (paper discharge driven roller 41b and paper discharge driving roller 41a) which are paper discharge means for discharging, and a displacement lever 51 (displacement member) which is displaced (rotated) by contacting the paper being discharged. ) And a photo sensor 52 for detecting the displacement state (rotation state) of the displacement lever 51. The paper discharge driven roller 41b is elastically biased by a spring with respect to the paper discharge drive roller 41a in order to discharge the paper with the paper discharge drive roller 41a interposed therebetween.
The present paper discharge device X is different from the conventional one in that a cover member 53 is provided to block the paper discharged to the paper discharge tray 42 from coming into contact with the displacement lever 51.
The cover member 53 is provided below the paper discharge position (the nip portion 41d of the roller pair) by the paper discharge roller 41, and is disposed so as not to prevent paper discharge. Here, as shown in FIG. 3, the cover member 53 is configured to be detachable by a snap-fastening mechanism with respect to the rotating shaft 41c of the discharge driving roller 41a. As a result, the assembly of the apparatus is easy, and the maintenance work can be facilitated because it can be easily removed during maintenance.
The cover member 53 is formed with a notch 53b through which the displacement lever 51 passes so as not to hinder the displacement operation (rotation operation) of the displacement lever 51. Here, the single cover member 53 is configured to block the discharged paper from contacting the displacement lever 51 in a certain range on both sides of the displacement path of the displacement lever 51. The notch portion 53b is provided in the cover member 53 over the certain range. For example, individual cover members (a plurality of cover members (displacement of the paper after discharge) are provided on both sides of the displacement lever 51 in the displacement direction). A configuration in which a cover member that blocks contact with the lever 51 is provided is also conceivable. In addition, a certain effect can be obtained only by providing a cover member on one side of the displacement lever 51. Further, the cover member 53 has a curved surface 53a that is convex in the direction of the paper discharge tray 42 (not shown in FIG. 2).
[0011]
FIG. 4 is a schematic cross-sectional view of the paper discharge device X.
The cover member 53 protrudes toward the paper discharge tray 42 with respect to the displacement lever 51 and the paper discharge roller 41, so that the paper discharged to the paper discharge tray 42 is transferred to the displacement lever 51 and the paper discharge tray 42. It is configured to block contact with the paper discharge drive roller 41a (lower roller).
For this reason, even when the curled paper is discharged to the paper discharge tray 42, the discharged paper comes into contact with the displacement lever 51 (lifts) and it is erroneously detected that JAM has occurred, or the paper is discharged. It is possible to prevent the discharged paper from being caught in the apparatus by the paper discharge driving roller 41a.
Further, since the curved surface 53a is formed, the curved surface 53a serves as a paper guide, and the rear end portion of the discharged paper (the downstream end portion in the paper discharge direction) is curved. Since the paper 53 slides smoothly onto the paper discharge tray 42 side, paper jams are less likely to occur.
[0012]
【The invention's effect】
As described above, according to the present invention, in the paper discharge device including the paper discharge sensor that detects the paper discharge state when the paper is discharged to the paper receiving portion, the paper discharged to the paper receiving portion. Since a cover member is provided to prevent the paper from contacting the displacement member of the paper discharge sensor, even if the curled paper is discharged to the paper receiving portion, the discharged paper will contact the displacement member and cause the paper discharge sensor to malfunction. It is possible to prevent detection and realize stable paper discharge detection. Furthermore, since the cover member also blocks the discharged paper from coming into contact with the paper discharge roller, the discharged paper can be prevented from being caught in the apparatus by the paper discharge roller.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus including a paper discharge device X according to an embodiment of the present invention.
FIG. 2 is a perspective view of a paper discharge device X according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a structure for attaching and detaching a cover member constituting the paper discharge device X according to the embodiment of the present invention to a shaft of a paper discharge roller.
FIG. 4 is a schematic cross-sectional view of a paper discharge device X according to an embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of a conventional paper discharge device A.
FIG. 6 is a cross-sectional view illustrating a state where curled paper is discharged by a conventional paper discharge device A.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10 ... Image reading part 20 ... Paper feed part 30 ... Printing part 31 ... Registration roller 32 ... Photosensitive drum 34 ... Charging unit 35 ... Developing tank 36 ... Transfer unit 38 ... Fixing apparatus 40 ... Paper discharge part 41 ... Discharge roller (paper discharge means)
41a: paper discharge driving roller (lower roller)
41b: paper discharge driven roller 41c: rotation shaft 42 of paper discharge driving roller ... paper discharge tray (paper receiving portion)
51 ... Displacement lever (displacement member)
52. Photo sensor (paper discharge sensor)
53 ... Cover member 53a ... Curved surface 53b of the cover member ... Notch portion of the cover member

Claims (2)

Displacement occurs when a pair of upper and lower paper discharge rollers that discharges the paper from the inside of the image forming apparatus to a paper receiving portion outside the apparatus, and the paper being discharged and the nip portion of the paper discharge roller pair at a position after passing. A paper discharge device comprising: a paper discharge sensor that detects a paper discharge state based on a displacement state of the displacement member;
Below the nip portion of the paper discharge roller pair, it is detachably attached to the rotation shaft of the lower roller of the paper discharge roller pair, and a convex curved surface is formed and displaced in the direction of the paper receiving portion. A cover member configured to block a sheet discharged to the sheet receiving portion from contacting the displacement member and the lower roller. A paper discharge device. An image forming apparatus comprising the paper discharge device according to claim 1 .

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