Paper feeding device and image forming apparatus

Abstract

It detects the loaded paper regardless of the paper's characteristics or the number of sheets. [Solution] A paper feeder comprising a stopping part that stops the leading edge of the supplied paper to regulate the paper transport start position, a restricting member whose stopping part moves in the paper transport direction, and a detection unit that detects the presence or absence of paper at the position where the paper is returned by the restricting member.

Description

Technical Field

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

Background Art

[0002] In Patent Document 1, there is disclosed a paper feeding device including a placement part on which a recording material can be placed, a roller member that feeds out the recording materials placed on the placement part one by one, a pair of side regulating members that regulate the width direction position of the recording material placed on the placement part and at least one of which is movable in the width direction, and a detection means that is disposed in the vicinity of the nip part between the recording material and the roller member, moves together with the side regulating members, and detects the presence or absence of the recording material based on the presence or absence of contact with the recording material on the placement part. Further, in Patent Document 2, there is disclosed an image forming apparatus including a manually insertable tray that can be opened and closed and a manual paper feeding device that feeds paper from the manually insertable tray, the manual paper feeding device including a manual tray on which paper is stacked, a pickup roller that feeds out the stacked paper, a feed roller and a retard roller that separate the fed-out paper into single sheets, and a detection means that detects the leading edge position of the set paper, the detection means checking the detection state immediately after a paper feeding command, and when the set position of the paper is not appropriate, not performing a paper feeding operation and prompting re-setting of the paper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The paper feeder is equipped with a regulating member that restricts the position of the leading edge of the paper in the direction of transport. In this paper feeder, the leading edge of the loaded paper is brought into contact with the regulating member, and the presence or absence of paper is detected. However, when loading paper, if the paper size is small, the number of sheets is small, or the paper is flimsy, the leading edge of the paper may be pushed back by the regulating mechanism during loading, potentially leading to a false detection of whether or not paper is present.

[0005] The present invention aims to detect loaded paper without being affected by the paper's characteristics or the number of sheets. [Means for solving the problem]

[0006] The invention described in claim 1 is a paper feeding device comprising: a stopping portion that abuts the leading edge of the supplied paper to regulate the paper transport start position, the stopping portion moving in the paper transport direction; and a detection portion that detects the presence or absence of paper at the position where the paper is returned by the regulating member. The invention described in claim 2 is a paper feeding device according to claim 1, characterized in that the detection unit detects the presence or absence of paper upstream of the regulating member in the transport direction from the regulating member when the leading edge of the paper hits the stopper and the paper transport start position is reached. The invention described in claim 3 is a paper feeding device according to claim 2, characterized in that the regulating member is rotatably provided around a rotation axis that is in a direction intersecting the transport direction and extending in the width direction of the paper, and the detection unit detects the presence or absence of paper upstream of the regulating member in the transport direction, with respect to the regulating member, where the stopper portion moves upstream in the transport direction due to the weight of the regulating member. The invention described in claim 4 is a paper feeding device according to claim 1, characterized in that the area in which the detection unit detects the paper is located upstream in the transport direction from the area in which the stopper unit moves in the transport direction. The invention described in claim 5 is a paper feeder according to claim 4, further comprising a transport member for transporting the supplied paper downstream in the transport direction, wherein the transport member is positioned upstream in the transport direction from the area for detecting the paper. The invention described in claim 6 is an image forming apparatus comprising the paper feeding device described in claims 1 to 5. [Effects of the Invention]

[0007] According to the invention of claim 1, the loaded paper can be detected without being affected by the characteristics or number of sheets of paper. According to the invention of claim 2, the presence or absence of paper can be detected using the abutment position against the regulating member as a downstream reference. According to the invention of claim 3, it is possible to detect paper that has been pushed back by the regulating member. According to the invention of claim 4, the paper can be detected without depending on the movement of the regulating member. According to the invention of claim 5, the paper that has been pushed back by the regulating member can be transported. According to the invention of claim 6, an image forming apparatus can be provided that detects the set paper without being affected by the characteristics or number of sheets of paper. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the image forming apparatus according to this embodiment. [Figure 2] This is a perspective view of the manual paper feed device as seen from the direction of arrow II in Figure 1. [Figure 3] This is a view of the manual paper feed device from the front of the paper in Figure 1. [Figure 4] This is an explanatory diagram illustrating the manual paper feed device with paper supplied to the tray. [Figure 5] This is an explanatory diagram illustrating a manual paper feed device in a state where the paper supplied to the tray has been pushed back. [Figure 6]These are explanatory diagrams to illustrate the positional relationship between the opening and closing of the manual feed tray and the feed roll. Figure 6(a) shows the tray in the open state, Figure 6(b) shows the process of the tray being closed, and Figure 6(c) shows the tray in the closed state. [Modes for carrying out the invention]

[0009] This embodiment will be described in detail below with reference to the attached drawings. <Configuration of an image forming apparatus> Figure 1 shows an image forming apparatus 1 in this embodiment. The image forming apparatus 1 is an example of a paper feeding device. The image forming apparatus 1 comprises an image forming unit 10 that forms a toner image on paper, and a fixing unit 20 that heats and pressurizes the toner image formed on the paper by the image forming unit 10. The image forming apparatus 1 also includes a paper feed tray 31 that supplies pre-sized paper, such as A4 or B4 size, to the image forming unit 10. Furthermore, the image forming apparatus 1 includes a manual feed device 50 that supplies specific paper, such as envelopes or cardboard, to the image forming unit 10. The image forming apparatus 1 also includes a control unit 500 that controls various operations of the image forming apparatus 1. The control unit 500 controls the image forming operation, for example, based on the detection result of the presence or absence of paper.

[0010] The image forming unit 10 comprises an image holder 11, a charging device 12, an exposure device 13, a developing device 14, a transfer device 15, and a cleaning device 16.

[0011] The image holder 11 has a photosensitive layer on its outer surface and rotates in the direction of arrow A shown in Figure 1. The charging device 12 charges the rotating image holder 11 to a predetermined potential. The exposure device 13 selectively exposes the image holder 11, which has been charged by the charging device 12, to form an electrostatic latent image on the image holder 11.

[0012] The developing device 14 develops the electrostatic latent image formed on the image carrier 11 with toner to form a toner image on the image carrier 11. The transfer device 15 forms an electric field between the transfer device 15 and the image carrier 11 to transfer the toner image on the image carrier 11 onto the paper. The cleaning device 16 removes toner and the like remaining on the image carrier 11 after transfer. Hereinafter, in this specification, the position where the toner image on the image carrier 11 is transferred onto the paper is referred to as the transfer portion Tp.

[0013] The image forming apparatus 1 includes a plurality of paper feed trays 31 inside the housing 1A thereof. Each of the paper feed trays 31 has a feed roll 32 that contacts the uppermost sheet among the plurality of stacked sheets and feeds the uppermost sheet into the paper path. Further, each of the paper feed trays 31 has a sorting mechanism 33 that sorts the sheets fed by the feed roll 32 one by one and feeds them to the downstream side. The sorting mechanism 33 is composed of a feed roll that is rotatably disposed and a retard roll whose rotation is restricted.

[0014] On the other hand, the manual paper feed device 50 is used when the user desires to print on a paper of a size not set in the paper feed tray 31, an envelope, thin paper, film paper, or the like. In the present embodiment, the manual paper feed device 50 is attached to the housing 1A so as to be rotatable and openable. Details of the manual paper feed device 50 will be described later.

[0015] When an instruction for image formation is given, the paper from the paper feed tray 31 or the manual paper feed device 50 is conveyed to the image forming unit 10 by the conveyance rollers provided in the paper path. In the paper path, a registration roller for supplying the paper conveyed from the paper feed tray 31 or the manual paper feed device 50 to the transfer unit Tp is attached. The registration roller stops when the paper is conveyed from the upstream side, and temporarily stops the conveyance of the paper. The registration roller starts rotating at a predetermined timing and supplies the paper to the transfer unit Tp. The paper on which the image has been transferred at the transfer unit Tp is subjected to heat and pressure treatment by the fixing unit 20, and the image is fixed. Thereafter, it is discharged to a discharge tray (not shown) by the conveyance roller.

[0016] <Manual paper feed device> Next, the details of the manual paper feed device 50 in the present embodiment will be described with reference to FIGS. 2 and FIGS. 3. FIG. 2 is a perspective view of the manual paper feed device 50 as viewed from the direction of arrow II in FIG. 1. FIG. 3 is a view of the manual paper feed device 50 as viewed from the front side of the paper surface of FIG. 1. FIGS. 2 and FIGS. 3 show a state where no paper is supplied to the manual paper feed device 50. The manual paper feed device 50 is an example of a paper feed device when it becomes an independent transaction target as an exchange part or a part to be separately attached.

[0017] As shown in FIG. 2, the manual paper feed device 50 includes a tray 51 that serves as a conveyance path for the paper or the stack of papers to be conveyed. The manual paper feed device 50 also includes a delivery roll 52 that sends out the paper supplied to the tray 51 to the downstream side. The delivery roll 52 is an example of a conveyance member. The manual paper feed device 50 also includes a sorting unit 56 that sorts the papers sent out by the delivery roll 52 one by one and sends them to the downstream side (see FIG. 3). The sorting unit 56 is composed of a feed roll 53 that is rotatably arranged and a retard roll 54 whose rotation is restricted. The manual paper feed device 50 also includes a cover member 90 that covers the upper part of the delivery roll 52 and the like.

[0018] Furthermore, the manual feed device 50 is equipped with a restricting member 60 on the tray 51, which serves as the paper transport path, to restrict the position of the leading edge of the paper in the transport direction (hereinafter also referred to as the "transport start position"). The manual feed device 50 is also equipped with a stopper mechanism 100 that restricts the movement of the restricting member 60 to a certain range. Furthermore, the manual feed device 50 is equipped with a detection member 70 used to detect the presence or absence of paper.

[0019] Furthermore, the manual paper feed device 50 is equipped with a detection sensor 55 that detects the presence or absence of paper based on the position and movement of the detection member 70. In this embodiment, the detection sensor 55 is composed of, for example, a non-contact sensor such as an optical sensor. Examples of optical sensors include light-shielding sensors and transmissive sensors. In this embodiment, as an example, a light-shielding sensor having a light-emitting part E and a light-receiving part is used as the detection sensor 55 to detect the presence or absence of paper. However, the detection sensor 55 is not limited to the above as long as it can detect the position of the detection member 70. The processing unit 56 may also be provided on the housing 1A side of the image forming apparatus 1.

[0020] The tray 51 has the function of holding paper and also serving as a transport path for paper transport, and is formed in a plate shape. The tray 51 is provided with a support surface (hereinafter referred to as the "paper support surface 51C") that supports the paper from below. The paper support surface 51C of the tray 51 has a first through hole 51D and a second through hole 51E that allow the tray 51 to pass through from above and below.

[0021] In this embodiment, the manual feed device 50 is provided with a rotating shaft 75, which is a first rod-shaped member extending in a direction perpendicular to the paper transport direction and parallel to the paper support surface 51C of the tray 51. This rotating shaft 75 is installed so as to be able to move up and down relative to the paper support surface 51C of the tray 51. This rotating shaft 75 is also the rotating shaft of the feed roll 52 and supports the regulating member 60. The rotating shaft 75 moves up and down, positioning the feed roll 52 upward when waiting before paper transport and downward when paper is being transported. As shown in Figure 3, when paper is being transported, the feed roll 52 moves downward as the rotating shaft 75 moves downward, until it reaches a position where it contacts the stack of paper.

[0022] The restricting member 60 has a support portion 61, an arm 62 extending from the support portion 61, and a stopper surface 63 that functions as a stopper against which the paper abuts. In this embodiment, the restricting member 60 is provided above the through hole 51D formed in the tray 51, and the arm 62 of the restricting member 60 is formed to protrude downward from the through hole 51D with the tray 51 in between.

[0023] The support portion 61 supports the restricting member 60 so that it can rotate relative to the rotation axis 75. As a result, the support portion 61 swings about the rotation axis 75. A protrusion 66 is formed on the support portion 61. This protrusion 66 is used to restrict the movement of the restricting member 60, which swings about the rotation axis 75, to a certain range. More specifically, it defines the movement of the restricting member 60 between the state in which there is no paper on the tray 51 and the state in which there is paper on the tray 51 and the paper is pushed to the transport start position.

[0024] The arm 62 facilitates the oscillation of the regulating member 60, which moves under its own weight. The abutment surface 63 is formed on the arm 62, and the shape of the arm 62 plays a role in determining the abutment position of the paper. In this embodiment, the arm 62 is formed to extend in an L-shape from the support portion 61, and the abutment surface 63 is formed on the inside of the L-shape. This configuration allows the abutment surface 63 to be in a shape favorable for transporting the paper P, such as being approximately perpendicular to the paper support surface 51C when the leading edge of the paper is abutted against it.

[0025] Furthermore, the abutment surface 63 is oriented perpendicular to the paper transport direction and has a constant thickness relative to the paper's width. This ensures that the paper being abutted is supported by a surface, stabilizing the abutment. Additionally, the abutment surface 63 is formed to have a constant height relative to the paper support surface 51C. This allows for the abutment position of a predetermined number of paper stacks to be set. In other words, even when multiple sheets of paper are supplied to the tray 51, the top and bottom sheets are supported at approximately the same angle to the abutment surface 63, reducing misalignment of the paper during setup. Thus, the regulating member 60 is formed into a predetermined shape and has a certain weight in order to achieve a stable paper abutment function.

[0026] In this embodiment, the manual paper feed device 50 is provided with a stopper mechanism 100 that restricts the movement of the swinging regulating member 60 to a certain range, including the area where the support portion 61 above the regulating member 60 is formed. The stopper mechanism 100 has a protrusion 66 formed on the support portion 61, and a first abutment wall 101 and a second abutment wall 102 that contact this protrusion 66. The second abutment wall 102 retracts to a position that does not obstruct the movement of the regulating member 60 when paper is being transported.

[0027] The protrusion 66 has a first surface 66a that contacts the first abutment wall 101 and a second surface 66b that contacts the second abutment wall 102. The position of the regulating member 60 before the paper is set is determined by the first surface 66a of the protrusion 66 contacting the first abutment wall 101. The position of the regulating member 60 after the paper is set is determined by the second surface 66b of the protrusion 66 contacting the second abutment wall 102.

[0028] Furthermore, as shown in Figure 2, the manual feed device 50 in this embodiment is provided with a second rod-shaped shaft member 80 that extends in a direction perpendicular to the paper transport direction and parallel to the paper support surface 51C of the tray 51. This shaft member 80 supports the detection member 70 above the through hole 51E formed on the tray 51.

[0029] As shown in Figure 3, the detection member 70 has a support portion 71 and an arm 72 extending from the support portion 71. The detection member 70 also has a contact surface 73 against which the paper abuts and a detection area 74 which is the area detected by the detection sensor 55.

[0030] The support portion 71 of the detection member 70 supports the detection member 70 so that it can rotate relative to the shaft member 80. As a result, the support portion 71 swings around the shaft member 80. When no paper is set, the detection member 70 stops in a position where it is stable due to its own weight.

[0031] The arm 72 of the detection member 70 promotes the oscillation of the detection member 70, which moves under its own weight. The abutment surface 73 of the detection member 70 is formed on the arm 72, and the leading edge of the paper abuts against this abutment surface 73.

[0032] The detection area 74 is the area to be detected by the detection sensor 55, and in this embodiment, it is located below the arm 72. In this embodiment, the detection member 70 has a stopper surface 73 formed above the through hole 51E formed on the tray 51, and the detection area 74 is formed below the through hole 51E. In other words, the stopper surface 73 of the detection member 70 is formed in the transport path, and the detection area 74 is formed on the opposite side of the tray 51 from the stopper surface 73. Furthermore, in this embodiment, the detection member 70 is positioned such that the detection area 74, at the location where it is positioned by its own weight, blocks the light emitted from the light-emitting part E of the detection sensor 55.

[0033] In this embodiment, the detection sensor 55 is positioned so as not to obstruct paper transport. More specifically, the detection sensor 55 is located below the tray 51, which functions as a paper transport path. Furthermore, in this embodiment, the detection sensor 55 is positioned upstream of the regulating member 60 in the paper transport direction.

[0034] <Movement of regulating and detecting members> Figure 4 is an explanatory diagram illustrating the manual feed device 50 in the state where paper has been supplied to tray 51. Figure 5 is an explanatory diagram illustrating the manual feed device 50 in the state where the paper supplied to tray 51 has been pushed back. The movements of the regulating member 60 and the detection member 70 will be explained using Figures 3 to 5.

[0035] As shown in Figure 3, in the pre-paper-loading state where no paper is supplied to the tray 51, the regulating member 60 moves by its own weight in the clockwise direction R1 shown in Figure 3 after the previous sheet of paper has been transported, and waits in the position shown in Figure 3. At this time, the first surface 66a of the protrusion 66 of the regulating member 60 is in contact with the first stop wall 101. This determines the stopping position of the regulating member 60 by its own weight. Also, at this time, the stop surface 63 of the regulating member 60 is in the pre-paper-loading position where the user can load paper.

[0036] Furthermore, in the pre-paper-loading state where no paper is supplied to tray 51, the detection member 70 moves by its own weight in the clockwise direction R1 shown in Figure 3 after the previous sheet of paper has been transported, and is in the position shown in Figure 3.

[0037] As shown in Figure 4, when paper is supplied to the tray 51, the regulating member 60 moves counterclockwise in the R2 direction from the state shown in Figure 3 as the abutment surface 63 of the inserted paper is pressed against it. At this time, if the paper size is not small, or if there are many sheets or the paper is stiff, the regulating member 60 does not push the paper back, but the second surface 66b of the protrusion 66 hits the second abutment wall 102 and stops moving. As a result, the abutment surface 63 of the regulating member 60 is set to the paper transport start position.

[0038] Furthermore, when paper is supplied to the tray 51, the detection member 70 moves in the counterclockwise direction R2 from the state shown in Figure 3, as the abutting surface 73 of the inserted paper is pressed against it. The detection member 70 then stops moving together with the regulating member 60 at the position where the regulating member 60 stops moving in the paper transport direction.

[0039] At this time, the detection member 70 is moving downstream in the paper transport direction, so that the light emitted from the light-emitting unit E is not blocked by the detection area 74. The detection sensor 55 detects the presence of paper when the light emitted from the light-emitting unit E is not blocked by the detection area 74.

[0040] Here, we consider, for example, cases where the paper size and weight of the paper to be placed in tray 51 are small, or where the number of sheets of paper is small, or where the paper is soft and lacks stiffness. In this case, even though paper is placed in tray 51, the leading edge of the paper may be pushed back by the weight of the restricting member 60 and the detection member 70. More specifically, as shown in Figure 5, for example, when there are few sheets of paper on tray 51, the force pushing the paper upstream by the weight of the restricting member 60 and the detection member 70 may become dominant. In this case, the restricting member 60 and the detection member 70 move in the clockwise direction R1, pushing the paper placed in tray 51 back upstream in the paper transport direction. In particular, the regulating member 60, which has a certain weight, pushes the paper set in the tray 51 back to the upstream side.

[0041] In this embodiment, the detection sensor 55 is positioned upstream of the regulating member 60 in the paper transport direction. More specifically, it is positioned upstream of the range in which the regulating member 60 swings, that is, the region in which the regulating member 60 moves in the paper transport direction. Therefore, in this embodiment, when the regulating member 60 moves to a position where it stops due to its own weight, the detection member 70 moves with the movement of the regulating member 60, but does not return to the position shown in Figure 3, but remains at the position shown in Figure 5. At this position shown in Figure 5, the light emitted from the light-emitting unit E is not blocked by the detection area 74 of the detection member 70. As a result, the detection sensor 55 can detect the presence of paper even when the paper is pushed back by the regulating member 60.

[0042] In this embodiment, the detection sensor 55 detects the presence of paper upstream of the regulating member 60 in the paper transport direction when the leading edge of the paper abuts against the abutting surface 63 of the regulating member 60 and the regulating member 60 stops at the paper transport start position. On the other hand, the detection sensor 55 also detects the presence of paper upstream of the regulating member 60 in the paper transport direction when the regulating member 60 moves upstream in the paper transport direction due to its own weight. In other words, in this embodiment, even when the paper is returned to the upstream side in the paper transport direction by the regulating member 60, the presence or absence of paper is detected at the position where the paper was returned.

[0043] Next, Figure 5 will be used to explain the position of the feed roll 52 during paper transport. When a paper transport command is issued for the paper supplied to tray 51, the rotating shaft 75 moves downward. As the rotating shaft 75 moves downward, the feed roll 52, which is located coaxially with the rotating shaft 75, also moves downward and comes into contact with the paper supplied to tray 51.

[0044] Then, the paper is transported by the rotational drive of the feed roll 52. At this time, the regulating member 60 is allowed to rotate counterclockwise, and the paper moves by pushing against the abutting surface 63 of the regulating member 60, and moves to the paper separation unit 56. After that, the paper, separated one sheet at a time by the paper separation unit 56, moves to the downstream side of the paper transport path.

[0045] In the manual paper feed device 50 of this embodiment, the following positions are arranged in order from the upstream side in the paper transport direction: position X where the feed roll 52 and the paper come into contact, position Y where the detection sensor 55 detects the paper, and position Z where the regulating member 60 stops due to its own weight. In other words, the position X where the feed roll 52 and the paper come into contact in this embodiment is located upstream in the paper transport direction from the position Z where the regulating member 60 stops due to its own weight. Furthermore, the position X where the feed roll 52 and the paper come into contact in this embodiment is located upstream in the paper transport direction from the position Y where the detection sensor 55 detects the paper. Therefore, the manual feed device 50 in this embodiment has a mechanism that allows the paper to be detected even when it is pushed back by the restricting member 60, and can then be transported downstream by the feed roll 52.

[0046] Figure 6 is an explanatory diagram illustrating the positional relationship between the opening and closing of the tray 51 of the manual feed device 50 and the feed roll 52. Figure 6(a) shows the tray 51 in the open state, Figure 6(b) shows the process of the tray 51 being closed, and Figure 6(c) shows the tray 51 in the closed state. In this embodiment, the manual paper feed device 50 is housed in the image forming apparatus 1 by opening and closing and rotating relative to the housing 1A.

[0047] More specifically, when the manual feed device 50 is opened as shown in Figure 6(a), and the tray 51 is closed, the cover member 90 and the tray 51 each rotate in the clockwise directions 6A and 6B as shown in Figure 6(b). When the manual feed device 50 is closed, the cover member 90 and the tray 51 are stored so as to be perpendicular to the horizontal direction of the housing 1A, as shown in Figure 6(c). At this time, the feed roll 52 located below the cover member 90 also moves in an arc clockwise direction 6A together with the cover member 90 and is stored in the housing 1A. In this embodiment, by enabling the manual feed device 50 to rotate in and out relative to the housing 1A, the machine width of the image forming apparatus 1 is reduced, and the feed roll 52 can be positioned further away from the housing 1A when in the open state.

[0048] The position of the feed roll 52 in the open state shown in Figure 6(a) protrudes significantly from the housing 1A side of the image forming apparatus 1 compared to the position of the feed roll 52 in the closed state shown in Figure 6(c). This enables the positional relationship of the manual feed device 50 shown in Figure 3, allowing the paper that has been pushed back by the regulating member 60 to be transported.

[0049] Although embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above embodiments. Embodiments of the present invention are not limited to manual paper feed devices, but can also be applied to, for example, an automatic document feeder that automatically feeds supplied paper one sheet at a time to the image reading unit. Furthermore, various modifications and substitutions of configurations that do not depart from the technical concept of the present invention are included in the present invention.

[0050] <Note> (((1))) A paper feeder comprising: a stopping portion that abuts the leading edge of the supplied paper to regulate the starting position of paper transport, the stopping portion moving in the paper transport direction, and a detection portion that detects the presence or absence of paper at the position where the paper is returned by the regulating member. (((2))) The paper feeding device according to (((1))), characterized in that the detection unit detects the presence or absence of paper upstream of the regulating member in the transport direction from the regulating member when the leading edge of the paper hits the stopper and the paper transport start position is stopped. (((3))) The paper feeding device according to (((1))) or (((2))), wherein the restricting member is provided so as to be rotatable about a rotation axis that is in a direction intersecting the transport direction and extending in the width direction of the paper, and the detection unit detects the presence or absence of paper upstream of the restricting member in the transport direction with respect to the restricting member, where the abutment portion moves upstream in the transport direction due to the weight of the restricting member. (((4))) The paper feeding device according to any one of (((1))) to (((3))), characterized in that the area where the detection unit detects the paper is located upstream in the transport direction from the area where the stopper unit moves in the transport direction. (((5))) A paper feeder according to any one of (((1))) to (((4))), further comprising a transport member for transporting the supplied paper downstream in the transport direction, wherein the transport member is positioned upstream in the transport direction from the area for detecting the paper. (((6))) An image forming apparatus equipped with a paper feeding device as described in any one of items (((1))) to (((5))).

[0051] According to the invention of (((1))), it is possible to detect the paper that has been set in place without being affected by the characteristics or number of sheets of paper. According to the invention of (((2))), the presence or absence of paper can be detected using the abutment position against the regulating member as a downstream reference. According to the invention of (((3))), it is possible to detect paper that has been pushed back by the regulating member. According to the invention of (((4))), the paper can be detected without depending on the movement of the regulating member. According to the invention of (((5))), the paper that has been pushed back by the regulating member can be transported. According to the invention of (((6))), an image forming apparatus can be provided that can detect the set paper without being affected by the characteristics or number of sheets of paper. [Explanation of symbols]

[0052] 1…Image forming apparatus, 10…Image forming unit, 11…Image holder, 12…Charging device, 13…Exposure device, 14…Developing device, 15…Transfer device, 16…Cleaning device, 20…Fixing unit, 31…Paper feed tray, 50…Manual feed device, 51…Tray, 52…Feed roll, 53…Feed roll, 54…Retard roll, 55…Detection sensor, 56…Screwing unit, 60…Regulating member, 61…Support unit, 62…Arm, 63…Butt surface, 70…Detection member, 74…Detection area, 75…Rotation axis, 80…Axis member, 100…Stopping mechanism

Claims

1. A restricting member having a stopper portion that abuts the leading edge of the supplied paper to regulate the paper transport start position, and the stopper portion moves in the paper transport direction, When the paper is returned by the aforementioned restricting member, a detection unit detects the presence or absence of paper at the position where the paper was returned, A paper feeder equipped with a paper feeder.

2. The detection unit detects the presence or absence of paper upstream of the regulating member in the transport direction when the leading edge of the paper hits the stopper and the paper transport start position is reached. The paper feeding device according to feature 1.

3. The regulating member is rotatably mounted around a rotation axis that is in a direction intersecting the transport direction and extending in the width direction of the paper, The detection unit detects the presence or absence of paper upstream of the regulating member in the transport direction, based on the regulating member's own weight causing the abutment portion to move upstream in the transport direction. The paper feeding device according to feature 2.

4. The area where the detection unit detects the paper is located upstream in the transport direction from the area where the stopper unit moves in the transport direction. The paper feeding device according to feature 1.

5. The system further comprises a transport member that transports the supplied paper downstream in the transport direction, The transport member is positioned upstream in the transport direction from the area that detects the paper. The paper feeding device according to feature 4.

6. An image forming apparatus comprising the paper feeding device according to claims 1 to 5.

Images