Paper feeder and image forming device

Abstract

To simplify sheet detection in an image forming device.SOLUTION: A paper feeder 10 comprises an operation member 50 brought into contact with a sheet to be displaced, and takes a first attitude when no sheet is placed on a tray, a second attitude when a sheet is placed on the tray but not conveyed, and a third attitude during sheet conveyance. A detection piece rotated along with a rotary shaft 60 of the operation member 50 is configured such that the operation member 50 is different in rotation position between the first attitude and the second attitude and between the second attitude and the third attitude.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a paper feeding device and an image forming apparatus including the paper feeding device.

Background Art

[0002] In an image forming apparatus, a paper is detected by a paper detection sensor to grasp the paper position, and based on detection results such as that the next paper does not come within a predetermined time or that a paper is continuously detected for a predetermined time or more, there is a configuration that is configured to detect a paper jam. For example, in Patent Document 1, when the discharge detection sensor that detects the discharge of the paper does not pass within a predetermined time after the rear end of the paper has passed through the paper detection sensor, it is determined that a jam has occurred and the paper conveyance is stopped. A configuration is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, the demand for miniaturization of image forming apparatuses has been increasing even more, and it has been required to provide various members constituting the image forming apparatus in a space-saving manner. Considering such circumstances, it is desirable to be able to grasp the paper position without arranging a plurality of detection sensors on the paper conveyance path, and to enable paper detection in a space-saving manner.

[0005] Therefore, an object of the present disclosure is to enable paper detection with a simpler configuration.

Means for Solving the Problems

[0006] The paper feeding device of the present disclosure includes a tray on which paper is placed, an operating member displaceable by contact with the paper, a rotating shaft that supports the operating member displaceably and rotates as the operating member displaces, a detection piece supported by the rotating shaft and rotating with the rotating shaft, and a detection sensor having a detection region overlapping the rotation locus of the detection piece. In the paper feeding device, the operating member assumes a first posture when no paper is placed on the tray, a second posture when paper is placed on the tray and not being conveyed, and a third posture during paper conveyance. The rotation position of the detection piece is different between when the operating member is in the first posture and when it is in the second posture, and the rotation position of the detection piece is different between when the operating member is in the second posture and when it is in the third posture.

[0007] In the paper feeding device, when the operating member is in the second posture, it is preferable that the rotation position of the detection piece is configured to overlap the detection region.

[0008] Also, in the paper feeding device, when the operating member is in the first posture and the third posture, it is preferable that the rotation position of the detection piece is outside the detection region.

[0009] Also, in the paper feeding device, the detection piece is preferably provided adjacent to the detection sensor and blocks or opens an optical path formed in the detection region.

[0010] Also, in the paper feeding device, the operating member is connected to a biasing member, and it is preferable that the operating member is displaced to the third posture against the biasing force of the biasing member and returns from the third posture under the action of the biasing force.

[0011] Also, in the paper feeding device, the operating member preferably includes a contact portion that contacts the leading edge of the paper on the tray in the second posture and is in sliding contact with the paper being conveyed in the third posture.

[0012] Also, in the paper feeding device, the operating member is preferably provided at the upstream end of a conveyance path continuous with the tray.

[0013] Also, an image forming apparatus including the sheet feeding device having the above configuration is also within the scope of the technical idea of the present disclosure.

Effects of the Invention

[0014] According to the present disclosure, in an image forming apparatus, it becomes possible to detect a sheet with a simpler configuration.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] An image forming apparatus 1 according to an embodiment of the present disclosure and a sheet feeding device 10 provided in the image forming apparatus 1 will be described with reference to the drawings.

[0017] (Image Forming Apparatus) FIG. 1 is an explanatory diagram showing a schematic configuration of an image forming apparatus 1 according to an embodiment. The image forming apparatus 1 has a copying function of reading a document and printing it on a sheet.

[0018] The image forming apparatus 1 includes a paper feeding apparatus 10, an image reading unit 12, a document conveying unit 13, an image forming unit 14, etc. The image forming unit 14 and the paper feeding apparatus 10 are provided in the apparatus main body 11. The image reading unit 12 and the document conveying unit 13 are mounted on the upper part of the apparatus main body 11.

[0019] The document conveying unit 13 conveys the document to the image reading unit 12. In the image reading unit 12, light is irradiated onto the document, and image data corresponding to the image of the document is generated from the reflected light. The image reading unit 12 has a scanner optical system accommodated below a document table on which a transparent glass is disposed. In the scanner optical system, light is irradiated onto the document on the document table, and an electrical signal corresponding to the reflected light from the document is generated as an image signal.

[0020] The image forming unit 14 includes a primary transfer unit 15, a secondary transfer unit 16, a belt cleaning unit 17, a fixing unit 18, etc., forms a visible image based on the image data, and forms an image on a sheet such as a predetermined recording sheet. The image data handled in the image forming apparatus 1 corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (for example, black). The image forming unit 14 is provided with four photosensitive drums 21 that act as image carriers, and each is equipped with a charging device, an exposure device, a developing device, and a photosensitive cleaning device (not shown) to form four types of toner images corresponding to each color of black, cyan, magenta, and yellow.

[0021] The primary transfer unit 15 has four photosensitive drums 21 and an intermediate transfer belt 22 that abuts on the photosensitive drums 21. The intermediate transfer belt 22 is an image carrier on which a toner image is formed, and is stretched between a transfer driving roller 23 and a transfer driven roller 24 and moves in a circular motion. By transferring and overlapping the toner images of each color formed on the surface of the photosensitive drum 21, a color toner image is formed on the surface of the intermediate transfer belt 22.

[0022] The transfer roller 25 provided in the secondary transfer unit 16 forms a nip portion with the intermediate transfer belt 22, and sandwiches and conveys the paper conveyed through the conveyance path 201 in the nip portion. When the paper passes through the nip portion, the toner image on the surface of the intermediate transfer belt 22 is transferred to the paper.

[0023] Toner and the like remaining on the intermediate transfer belt 22 are collected by the belt cleaning unit 17. In the fixing unit 18, the paper with the unfixed toner image transferred thereon is sandwiched between the heating roller 26 and the pressure roller 27 and conveyed while being heated and pressurized to thermally fix the unfixed toner image on the paper.

[0024] The paper feeding device 10 supplies paper to the image forming unit 14 one sheet at a time with either the paper feed cassette 29 or the manual feed tray 30 as the paper feed source. The paper feed cassette 29 is provided below the image forming unit 14. The paper feed cassette 29 stores the paper used for image formation. The paper is pulled out from the paper feed cassette 29 by the pickup roller 41, conveyed through the conveyance path 201, and carried out to the discharge tray 28 via the secondary transfer unit 16 and the fixing unit 18.

[0025] The manual feed tray 30 is provided on the side surface of the apparatus main body 11 so as to be openable and closable, and is a tray on which the paper used for image formation can be placed. The paper placed on the manual feed tray 30 is pulled out by the paper feed roller 31, guided to the conveyance path 201 via the horizontal conveyance path 202, and conveyed to the image forming unit 14.

[0026] On the conveyance path 201, roller pairs such as the registration roller 42, the conveyance roller 43, and the paper discharge roller 44 are arranged. The registration roller 42 temporarily stops the paper, aligns the leading edges of the paper, and then starts the conveyance of the paper in accordance with the transfer timing at the nip portion between the intermediate transfer belt 22 and the transfer roller 25. The conveyance roller 43 and the paper discharge roller 44 promote the conveyance of the paper.

[0027] When performing image formation not only on the front surface but also on the back surface of the sheet, the sheet is conveyed from the paper discharge roller 44 to the reverse conveyance path 203, the front and back of the sheet are reversed, and the sheet is guided to the resist roller 42, and image formation is performed on the back surface in the same manner as on the front surface.

[0028] (Paper feeding device) As an embodiment of the paper feeding device according to the present disclosure, the paper feeding device 10 applied to the manual feed tray 30 will be described in detail. FIG. 2 is a partial cross-sectional view showing the paper feeding device 10. The paper feeding device 10 supplies the paper placed on the manual feed tray 30 to the image forming unit 14 via the horizontal conveyance path 202, which is a conveyance path continuous with the manual feed tray 30.

[0029] As shown in FIG. 2, the paper feeding device 10 according to the exemplary embodiment includes a manual feed tray 30 on which sheets are stacked, a paper feed roller 31 provided at the upstream end of the horizontal conveyance path 202 at the connection end (front end) with the manual feed tray 30, and a separation roller 32 pressed against the paper feed roller 31. Note that, for convenience of explanation, the conveyance path continuous with the manual feed tray 30 is referred to as the horizontal conveyance path 202 separately from the conveyance path 201, but such a conveyance path is not limited to being provided horizontally in the apparatus main body 11 and may be provided as any path.

[0030] The paper feeding device 10 guides the paper from the manual feed tray 30 to the nip portion between the paper feed roller 31 and the separation roller 32 by the rotation of the paper feed roller 31. The sheets are separated one by one from the manual feed tray 30 and sent out to the horizontal conveyance path 202, and are conveyed in the conveyance direction B.

[0031] The manual feed tray 30 includes a placement surface 301 on which sheets are placed. When the manual feed tray 30 is in an open state with respect to the side surface of the apparatus main body 11, its rear end is located above the shaft fulcrum of the front end, and the entire manual feed tray 30 is arranged to incline at a predetermined inclination angle toward the downstream side in the paper feeding direction A. The placement surface 301 is arranged to face obliquely upward. When a sheet is placed on the placement surface 301, the sheet can move downstream in the paper feeding direction A by its own weight.

[0032] At the front end of the manual feed tray 30, as a sheet detection means, an operating member 50 and a rotation shaft 60 that rotatably supports the operating member 50 are provided. The operating member 50 is disposed below the paper feed roller 31 (in a direction intersecting the paper feed direction A), and is provided at the upstream end of the horizontal conveyance path 202 that is continuous with the front end of the manual feed tray 30. The axial direction X of the rotation shaft 60 that supports the operating member 50 is provided in parallel with the axial direction of the rotation shaft 311 of the paper feed roller 31.

[0033] FIG. 3 is a partial cross-sectional view of the paper feeding device 10. FIG. 3 shows a portion on the front side in the axial direction of the rotation shaft 60 shown in FIG. 2 where the detection piece 70 is provided. At the front end of the manual feed tray 30, as a sheet detection means, a detection piece 70 that rotates together with the rotation shaft 60 and a detection sensor 80 are further provided.

[0034] Returning to FIG. 2, the lower end of the operating member 50 is supported by the rotation shaft 60. The operating member 50 extends upward from the lower end, and the upper end extends in a direction away from the rotation shaft 60. In the illustrated embodiment, the operating member 50 has a shape integrally including a contact portion 51 located near the front end of the manual feed tray 30, a locking portion 52 extending from the contact portion 51 toward the downstream side in the paper feed direction A, and a connecting portion 53 extending from the locking portion 52 toward the rotation shaft 60. The operating member 50 is provided so as to be able to open and close the paper feed port 33 between the front end of the manual feed tray 30 and the horizontal conveyance path 202.

[0035] The contact portion 51 and the locking portion 52 of the operating member 50 extend in directions intersecting each other. In the state of FIG. 2, the contact portion 51 extends in the vertical direction and closes the paper feed port 33. The contact portion 51 and the locking portion 52 are formed in a bent shape. The locking portion 52 can lock at the corner with the contact portion 51 on the placement surface 301 of the manual feed tray 30.

[0036] The connecting portion 53 of the operating member 50 also extends in a direction intersecting the locking portion 52, and the corner between the locking portion 52 and the connecting portion 53 is formed in a bent shape. The operating member 50 has a bent shape with two corners as a whole, and the cross-sectional shape as viewed in the axial direction of the rotation shaft 60 is formed in a substantially Z shape or a substantially S shape.

[0037] The actuating member 50 is coupled to the rotating shaft 60 at the connecting portion 53 and is supported by the rotating shaft 60. The actuating member 50 is supported by the rotating shaft 60 and is provided so as to be displaceable about the axis of the rotating shaft 60.

[0038] The rotating shaft 60 is arranged with the axial direction X being a direction orthogonal to the paper feeding direction A and orthogonal to the horizontal conveyance path 202. The axial direction X of the rotating shaft 60 is made parallel to the axial direction of the paper feeding roller 31. The rotating shaft 60 is provided to support the actuating member 50 displaceably and to rotate freely about its axis in conjunction with the displacement of the actuating member 50.

[0039] The detection piece 70 is provided near the end in the axial direction X of the rotating shaft 60. As shown in FIG. 3, the detection piece 70 is supported by the rotating shaft 60 and is provided so as to be rotatable together with the rotating shaft 60. In the illustrated embodiment, the detection piece 70 has a strip-shaped or substantially fan-shaped shape extending from the rotating shaft 60 in the radial direction orthogonal to the axial direction X of the rotating shaft 60. The detection piece 70 is arranged upward with respect to the rotating shaft 60.

[0040] The detection sensor 80 is arranged near the end of the rotating shaft 60 and adjacent to the detection piece 70. In the illustrated embodiment, the detection sensor 80 is provided above the rotating shaft 60. The detection sensor 80 is, for example, a photosensor having a light emitting portion and a light receiving portion facing each other with a predetermined interval therebetween, and an optical path extending from the light emitting portion toward the light receiving portion is formed in the detection region 81. This detection sensor 80 is arranged so that the rotation locus of the detection piece 70 overlaps with the detection region 81. In the detection region 81, when the optical path is blocked or opened by the detection piece 70, the ON / OFF of the detection sensor 80 is switched and a signal is output.

[0041] Figures 4 and 5 are partial cross-sectional views of the paper feeding device 10, showing the manual tray 30 with paper placed thereon. In the state shown in Figure 2, no paper is placed on the manual tray 30, and the placement surface 301 is exposed. At this time, the operating member 50 is in a first posture where the locking portion 52 is locked to the placement surface 301, and the abutting portion 51 is in a position closing the paper feed port 33.

[0042] Next, as shown in Figure 4, when the paper P is placed on the placement surface 301 of the manual tray 30, the abutting portion 51 of the operating member 50 abuts against the leading edge (the downstream end in the paper feed direction A) of the paper P. The operating member 50 receives the pressing force in the downstream direction of the paper feed direction A due to the self-weight of the paper P and rotates and displaces about the rotation shaft 60. As a result, the operating member 50 assumes a second posture. The abutting portion 51 is disposed in a direction substantially perpendicular to the placement surface 301. At this time, the conveyance of the paper P has not been started.

[0043] Next, when the paper feed roller 31 is driven to rotate and the conveyance of the uppermost paper P placed on the manual tray 30 is started, as shown in Figure 5, the paper P slides on the tip of the abutting portion 51 of the operating member 50 and is conveyed in the conveyance direction B. The operating member 50 receives the pressing force of the conveyed paper P and rotates from the second posture to the third posture.

[0044] In this way, the operating member 50 is displaced from the first posture to the second posture when the paper P is placed on the manual tray 30, and is displaced from the second posture to the third posture when the conveyance of the paper P on the manual tray 30 is started. Also, the operating member 50 is connected to a biasing member (not shown), and is displaced from the first posture to the second posture and from the second posture to the third posture against the biasing force of the biasing member. When the conveyance of the paper P is completed, it returns from the third posture to the second posture under the biasing force. In the second posture, the paper P on the manual tray 30 abuts against the abutting portion 51 of the operating member 50. The biasing member may be, for example, a kick spring externally mounted on the rotation shaft 60, or a coil spring shrink-fitted between the operating member 50 and the apparatus main body 11.

[0045] Figures 6 and 7 are partial cross-sectional views of the paper feeding device 10, showing the states of the detection piece 70 respectively. FIG. 6 shows the case when the operating member 50 is in the second posture, and FIG. 7 shows the case when the operating member 50 is in the third posture.

[0046] The rotational position of the detection piece 70 is different between when the operating member 50 is in the first posture and when it is in the second posture. Also, the rotational position of the detection piece 70 is different between when the operating member 50 is in the second posture and when it is in the third posture. Accordingly, the output signal of the detection sensor 80 is configured to change.

[0047] That is, as shown in FIG. 2, when the operating member 50 is in the first posture, as shown in FIG. 3, the detection piece 70 tilts toward the manual feed tray 30, deviates from the detection area 81 of the detection sensor 80, and remains stationary without reaching the detection area 81. The optical path of the detection area 81 is open. The detection sensor 80 outputs a signal indicating OFF.

[0048] As shown in FIG. 4, when the paper P is placed on the manual feed tray 30, the operating member 50 assumes the second posture. Along with the displacement of the operating member 50 to the second posture and the rotation of the rotation shaft 60, the detection piece 70 rotates about the rotation shaft 60. As shown in FIG. 6, the detection piece 70 reaches a position overlapping the detection area 81 of the detection sensor 80. The optical path of the detection area 81 is blocked by the detection piece 70. The detection sensor 80 outputs a signal indicating ON.

[0049] As shown in FIG. 5, during the conveyance of the paper P placed on the manual feed tray 30, the operating member 50 assumes the third posture. As the operating member 50 is displaced from the second posture to the third posture and the rotation shaft 60 rotates, the detection piece 70 further rotates. As shown in FIG. 7, the detection piece 70 passes through the detection area 81 and deviates from the detection area 81, tilting to the side opposite to the manual feed tray 30. The optical path of the detection area 81 is open, and the detection sensor 80 outputs a signal indicating OFF.

[0050] As the trailing edge of the sheet P passes through the nip between the paper feed roller 31 and the separation roller 32 and is conveyed to the horizontal conveyance path 202, the sheet P separates from the contact portion 51 of the operating member 50. The operating member 50 returns from the third posture to the second posture shown in FIG. 4 by the biasing force of the biasing member. Along with the displacement of the operating member 50 to the second posture and the rotation of the rotation shaft 60, the detection piece 70 also rotates and returns to the state shown in FIG. 6. The detection piece 70 reaches a position overlapping the detection area 81 of the detection sensor 80. The optical path of the detection area 81 is blocked by the detection piece 70, and the output signal of the detection sensor 80 switches from OFF to ON.

[0051] Therefore, when the operating member 50 is displaced among the first posture, the second posture, and the third posture and returns to the second posture again, the detection piece 70 opens, blocks, opens, and then blocks the optical path. At this time, the output signal of the detection sensor 80 changes as OFF, ON, OFF, and then ON.

[0052] When the output signal of the detection sensor 80 changes from ON to OFF, the start of conveyance of the sheet P can be grasped, and by subsequently changing from OFF to ON again, the passage of the trailing edge of the sheet P can be grasped. When image formation is completed and the sheet P on the manual feed tray 30 runs out, the operating member 50 returns to the first posture.

[0053] The blocking time of the optical path in the detection sensor 80 is equal to or less than a certain time (for example, the paper feed time of one sheet from the manual feed tray 30). In the image forming apparatus 1, based on the detection result of the paper detection means configured in this way and the size and conveyance speed of the sheet P applied to image formation, it is possible to grasp the position of the sheet on the conveyance path 201. In this case, since it is possible to grasp the sheet position with one detection sensor 80 provided in the paper feed device 10 and perform conveyance control, the number of detection sensors can be reduced compared to conventional devices that required the installation of a plurality of detection sensors. Therefore, in the image forming apparatus 1 including the paper feed device 10, the sheet can be detected with a simple configuration, and the apparatus can be miniaturized and the cost can be reduced.

[0054] In the above-described embodiment, the paper feeding device 10 has been described as an example provided in the manual feed tray 30 of the image forming apparatus 1. However, the present disclosure is not limited thereto, and can be applied to the entire apparatus that feeds a sheet such as paper. The image forming apparatus 1 including such a paper feeding device 10 may be a monochrome image forming apparatus or a color image forming apparatus (for example, a tandem type color image forming apparatus). The image forming apparatus 1 may be a multifunction machine having a printer function, a scanner function, a facsimile function, etc. in addition to a copying function.

[0055] The present disclosure is not limited to the above-described embodiment, and various modifications are possible. That is, embodiments obtained by appropriately combining technical means modified within the scope not departing from the gist of the present disclosure are also included in the technical scope of the present disclosure.

Explanation of Reference Numerals

[0056] 1 Image forming apparatus 10 Paper feeding device 11 Apparatus main body 29 Paper feed cassette 30 Manual feed tray 31 Paper feed roller 32 Separation roller 50 Actuating member 51 Contact portion 52 Locking portion 53 Connection portion 60 Rotation shaft 70 Detection piece 80 Detection sensor 81 Detection area

Claims

1. A tray on which paper is placed, An actuating member displaceable by contact with the paper, A rotating shaft that supports the actuating member so as to be displaceable and rotates as the actuating member displaces, A detection piece supported by the rotating shaft and rotating together with the rotating shaft, A paper feeding device comprising a detection sensor having a detection area overlapping the rotation locus of the detection piece, wherein The actuating member assumes a first posture when no paper is placed on the tray, a second posture when paper is placed on the tray and not being conveyed, and a third posture during paper conveyance, A paper feeding device, characterized in that the rotation position of the detection piece is different between when the actuating member is in the first posture and when it is in the second posture, and the rotation position of the detection piece is different between when the actuating member is in the second posture and when it is in the third posture.

2. In the paper feeding device according to Claim 1, A paper feeding device, characterized in that when the actuating member is in the second posture, the rotation position of the detection piece overlaps the detection area.

3. In the paper feeding device according to Claim 2, A paper feeding device, characterized in that when the actuating member is in the first posture and the third posture, the rotation position of the detection piece is outside the detection area.

4. In the paper feeding device according to Claim 1, A paper feeding device, characterized in that the detection piece is provided adjacent to the detection sensor and blocks or opens an optical path formed in the detection area.

5. In the paper feeding device according to Claim 1, A paper feeding device, characterized in that the actuating member is connected to a biasing member, displaces to the third posture against the biasing force of the biasing member, and returns from the third posture under the action of the biasing force.

6. In the paper feeding device according to Claim 1, A paper feeding device, characterized in that the actuating member has a contact portion that contacts the leading edge of the paper on the tray in the second posture and slidably contacts the paper being conveyed in the third posture.

7. In the paper feeding device according to Claim 1, A paper feeding device, characterized in that the actuating member is provided at the upstream end of a conveyance path continuous with the tray.

8. An image forming apparatus, characterized by comprising the paper feeding device according to any one of Claims 1 to 7.

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