Medium supply device

Abstract

To provide a medium supply device which accurately performs skew correction, and which suppresses conveyance failure of a medium.SOLUTION: A medium supply device (paper feeding device 1) includes: a loading table 10 on which a plurality of media (sheet P) is loaded; a conveyance mechanism 20 for conveying an uppermost medium (sheet P1) out of the plurality of media loaded on the loading table 10; a suction mechanism 30 for allowing the conveyance medium 20 to adsorb the uppermost medium by sucking air (suction air A1); a skew correction roller (first resister roller pair 41 and second resister roller pair 42) which receives a medium from the conveyance mechanism 20, and which corrects the skew of the medium; and a control part 71 for controlling the suction mechanism 30 so as to cut off at least part of the suction of air, in a state where the medium is positioned across the conveyance mechanism 20 and the skew correction roller, in the case where at least the skew correction roller corrects the skew of the medium.SELECTED DRAWING: Figure 6C

Description

[Technical field]

[0001] The present invention relates to a media supply device. [Background technology]

[0002] Conventionally, a method is known in which a sheet is abutted against a pair of registration rollers to form slack and thereby correct the skew of the sheet. Also, a sheet transport device has been proposed in which, when a sheet is abutted against the pair of registration rollers to correct the skew, the nip of an upstream roller pair located upstream of the pair of registration rollers in the transport direction is opened (for example, see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-035766 A [Patent Document 2] JP 2014-061957 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, by opening the nip of the upstream roller pair when correcting skew, it is possible to prevent wrinkles from occurring due to twisting of the paper in thin paper, and to prevent the paper orientation from becoming unable to be changed in thick paper, compared to when the nip is not opened when correcting skew.

[0005] However, when the nip of the upstream roller pair is released during skew correction, the nip pressure of the paper becomes unstable during the nip release and re-nip operation due to the elasticity of the upstream roller pair and the backlash and springiness of the mechanism that drives the upstream roller pair. Also, when correcting skew of paper handed over from the paper feed roller of the paper feeder, the nip pressure of the paper becomes unstable due to variations in the height of the topmost paper stacked in the paper feeder. If the nip pressure of the paper is not stable, transport defects such as fluctuations in the transport amount and transport position deviations due to slippage are likely to occur, especially when the paper is transported at high speed.

[0006] An object of the present invention is to provide a medium supplying device that can accurately correct skew and suppress medium transport failure. [Means for solving the problem]

[0007] In one aspect, a medium supplying device includes a loading platform on which multiple media are loaded, a transport mechanism that transports the topmost medium of the multiple media loaded on the loading platform, a suction mechanism that adsorbs the topmost medium to the transport mechanism by sucking in air, a skew correction roller that receives the medium from the transport mechanism and corrects skew of the medium, and a control unit that controls the suction mechanism to block suction of at least some of the air when the medium is positioned between the transport mechanism and the skew correction roller, at least when the skew correction roller corrects skew of the medium. Effect of the Invention

[0008] According to this aspect, it is possible to accurately correct skew and prevent medium transport failure. [Brief description of the drawings]

[0009] [Figure 1] 1 is a front view showing an internal configuration of an image forming system including a paper feed device according to an embodiment; [Diagram 2] FIG. 4 is a diagram illustrating a control configuration of a paper feed device according to an embodiment. [Diagram 3] 4 is a plan view showing a configuration around a first registration roller pair and a second registration roller pair in the embodiment. FIG. [Figure 4A] FIG. 1 is a first plan view showing a blocking section of a suction mechanism according to an embodiment. [Figure 4B] FIG. 2 is a second plan view showing the blocking portion of the suction mechanism according to the embodiment. [Diagram 5] 4 is a timing chart for explaining the operation of each unit in one embodiment. [Figure 6A] FIG. 1 is a front view (part 1) for explaining a paper feeding operation in one embodiment. [Figure 6B] FIG. 11 is a front view (part 2) for explaining a paper feeding operation in the embodiment. [Figure 6C] FIG. 11 is a front view (part 3) for explaining a paper feeding operation in the embodiment. [Figure 6D] FIG. 4 is a front view (part 4) for explaining a paper feeding operation in one embodiment. [Figure 7] FIG. 11 is a plan view for explaining skew correction in one embodiment. [Figure 8] 11 is a table showing an example of the opening degree of a shutter of a suction mechanism according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a medium feeding device according to an embodiment of the present invention will be described with reference to the drawings, taking a paper feeding device 1 as an example.

[0011] FIG. 1 is a front view showing the internal configuration of an image forming system 100 including a paper feeder 1 according to an embodiment.

[0012] FIG. 2 is a diagram showing a control configuration of the sheet feeding device 1. As shown in FIG.

[0013] FIG. 3 is a plan view showing the configuration of the first registration roller pair 41 and the second registration roller pair 42 and their surroundings.

[0014] Note that the up-down, front-back, left-right directions shown in Figures 1 and 3, and Figures 4A, 4B, 6A to 6D, and 7 described below, are vertical directions, and the front-back and left-right directions are horizontal directions, although the orientation of the conveying direction D can be changed as appropriate depending on the configuration of the paper feeding device 1, etc.

[0015] The paper feeder 1 shown in FIG. 1 is disposed integrally with the image forming apparatus 101, and supplies paper P to the image forming section 110 of the image forming apparatus 101. However, the paper feeder 1 may be disposed separately from the image forming apparatus 101. The target to which the paper feeder 1 feeds paper P is not limited to the image forming apparatus 101, and may be other devices such as a conveying device or a processing device (for example, an inspection device or a post-processing device after printing). The paper P is an example of a medium, and the medium may be other media such as a film. A plurality of paper feeders 1 may be disposed, for example, vertically aligned, and the plurality of paper feeders 1 may feed paper P to a single device (for example, the image forming apparatus 101).

[0016] As shown in FIG. 1, the paper feeding device 1 includes a loading platform 10, a conveying mechanism 20, a suction mechanism 30, a first registration roller pair 41 and a second registration roller pair 42 which are examples of skew correction rollers, a floating air blowing mechanism 50, a separation air blowing mechanism 60, a first detection sensor S1 and a second detection sensor S2.

[0017] As shown in FIG. 2, the paper feeding device 1 further includes a control unit 71, a memory unit 72, an interface unit 73, a loading tray drive unit 81, a conveying mechanism drive unit 82, a first registration roller pair drive unit 83, and a second registration roller pair drive unit 84.

[0018] A plurality of sheets of paper P are loaded on the loading platform 10 shown in Fig. 1. The loading platform 10 is raised and lowered by driving a loading platform drive unit 81 shown in Fig. 2. As an example, the control unit 71 controls the loading platform drive unit 81 to raise the loading platform 10 when light emitted horizontally by a light emitting unit of a loading surface detection sensor (not shown) at a predetermined loading surface height is no longer blocked by the sheets of paper P and is received by a light receiving unit of the loading surface detection sensor. As a result, the height of the uppermost sheet of paper P1 among the plurality of sheets of paper P loaded on the loading platform 10 is maintained at the specified loading surface height.

[0019] The conveying mechanism 20 has a conveying belt 21 and pulleys 22, 23 around which the conveying belt 21 is stretched. One of the pulleys 22, 23 is a driving pulley, and the other is a driven pulley. The driving pulley rotates by being driven by a conveying mechanism driving unit 82 shown in FIG. 2, thereby rotating the conveying belt 21. As a result, the conveying mechanism 20 conveys the uppermost sheet P1 of the multiple sheets P stacked on the stacking tray 10 in the conveying direction D (right side in FIG. 1) and delivers it to the first registration roller pair 41 and the second registration roller pair 42.

[0020] 3, only one transport mechanism 20 is disposed in the center of the width direction W perpendicular to the transport direction D of the paper P. However, a plurality of transport mechanisms 20 may be disposed side by side in the width direction W. In this case, it is preferable that each transport mechanism 20 is provided with one suction mechanism 30, which will be described later.

[0021] The conveyor belt 21 has a plurality of through holes (not shown) for passing suction air A1, which is air sucked by a suction mechanism 30 described later. Note that the conveyor mechanism 20 may have another conveyor member such as a roller conveyor instead of the conveyor belt 21 as a conveyor member for conveying the paper P. However, since the conveyor belt 21 can adsorb and convey the paper P while making surface contact with the paper P, it is preferable that the conveyor mechanism 20 has the conveyor belt 21 as a conveyor member.

[0022] The suction mechanism 30 is disposed, for example, in an area surrounded by the conveyor belt 21 of the conveyor mechanism 20. The suction mechanism 30 causes the uppermost sheet P1 of the multiple sheets P loaded on the stacking table 10 to be adsorbed to the conveyor mechanism 20 by a suction source (for example, a suction fan) (not shown) sucking suction air A1 through multiple through holes provided in the conveyor belt 21.

[0023] The suction mechanism 30 has a blocking unit 31 that blocks the suction of the suction air A1. The blocking unit 31 is an example of a suction blocking means that blocks the suction of at least a portion of the air. The blocking unit 31 is disposed, for example, on the bottom surface inside the suction mechanism 30 (inside the chamber). Note that the blocking unit 31 may also be disposed in another portion, such as the bottom surface outside the suction mechanism 30 (outside the chamber).

[0024] 4A and 4B are plan views showing the blocking section 31 of the suction mechanism 30. FIG.

[0025] As shown in FIG. 4A, the blocking unit 31 has a shutter 31a, an opening member 31b, and a rotating shaft member 31c.

[0026] The shutter 31a is driven by a shutter drive unit (eg, an actuator such as a motor) (not shown) to swing (rotate) in both clockwise and counterclockwise directions within a range of, for example, 45 degrees around a rotary shaft member 31c as a central axis of rotation.

[0027] The shutter 31a has, for example, four blades 31a-1. The four blades 31a-1 are provided at equal intervals (for example, at 90 degree intervals) in the rotation direction of the shutter 31a.

[0028] The opening member 31b is, for example, a disk-shaped plate material. The opening member 31b has, for example, four through holes 31b-1 for passing the suction air A1. The four through holes 31b-1 are provided at equal intervals (for example, 90 degree intervals) in the rotation direction of the shutter 31a, similar to the blade portion 31a-1.

[0029] The shutter 31a swings (moves) between a retracted position (1) in which the blade portion 31a-1 does not cover the through hole 31b-1 and thus does not block the suction of the suction air A1, as shown in FIG. 4A, and a blocking position (2) in which the blade portion 31a-1 covers the through hole 31b-1 and thus blocks the suction of the suction air A1 shown in FIG. 3, as shown in FIG. 4B.

[0030] When the shutter 31a moves between a retracted position that covers a through hole provided in the bottom surface of the suction mechanism 30 and a blocking position, the opening member 31b having the through hole 31b-1 can be omitted.

[0031] Furthermore, to block the suction of the suction air A1, instead of using the blocking unit 31 with the rotating shutter 31a, a blocking unit having a sliding shutter that moves linearly in a direction to open and close the flow path of the suction air A1 may be used. To block the suction of the suction air A1, the suction force of the suction source (e.g., a suction fan) of the suction mechanism 30 may be adjusted, or when multiple suction sources are arranged in the suction mechanism 30, the operation of some or all of the suction sources may be stopped. In this way, the method of blocking the suction of at least a portion of the suction air A1 is not particularly limited.

[0032] As shown in FIG. 3, the first registration roller pair 41 and the second registration roller pair 42 are disposed at the same position in the conveying direction D of the paper P, and on one side and the other side in the width direction W of the paper P. The first registration roller pair 41 and the second registration roller pair 42 receive the paper P from the conveying mechanism 20 and correct the skew of the received paper P. The first registration roller pair 41 and the second registration roller pair 42 are conveying members (conveying means for conveying the paper P) that nip the paper P and are closest to the conveying mechanism 20 on the downstream side in the conveying direction D of the conveying mechanism 20. In other words, no conveying member that nips the paper P is disposed between the conveying mechanism 20 and the first registration roller pair 41 and the second registration roller pair 42. In this way, the conveying mechanism 20 delivers the paper P to the first registration roller pair 41 and the second registration roller pair 42 without a conveying member that nips the paper P.

[0033] The first registration roller pair 41 rotates by being driven by the first registration roller pair drive unit 83, and the second registration roller pair 42 rotates by being driven by the second registration roller pair drive unit 84. Therefore, the first registration roller pair 41 and the second registration roller pair 42 can transport the paper P with different driving forces (transport forces). Therefore, by adjusting the driving forces of the first registration roller pair 41 and the second registration roller pair 42, the transport amount of the paper P can be adjusted on one side and the other side in the width direction W perpendicular to the transport direction D of the paper P, and the skew of the paper P can be corrected. Note that, in order to adjust the transport amount of the paper P on one side and the other side in the width direction W of the paper P, other configurations such as a configuration in which the paper P is transported while the skew correction roller is tilted in a horizontal plane may be adopted.

[0034] As shown in FIG. 3, the first detection sensor S1 and the second detection sensor S2 are disposed at the same position in the transport direction D of the paper P, and on one side and the other side in the width direction W of the paper P.

[0035] The first detection sensor S1 and the second detection sensor S2 are, for example, reflection sensors or transmission sensors, and detect the presence or absence of the paper P. The control unit 71, which will be described later, can determine whether the paper P is skewed based on the difference between the time when the first detection sensor S1 detects the paper P and the time when the second detection sensor S2 detects the paper P.

[0036] The first detection sensor S1 and the second detection sensor S2 are disposed downstream of the first registration roller pair 41 and the second registration roller pair 42 in the conveying direction D and upstream of the conveying roller pair 166, 167 of the image forming device 101. However, the first detection sensor S1 and the second detection sensor S2 may be disposed upstream of the first registration roller pair 41 and the second registration roller pair 42 in the conveying direction D. Also, the first detection sensor S1 and the second detection sensor S2 may be disposed as a part of the image forming device 101, and the control unit 71 of the sheet feeding device 1 may obtain detection signals from the first detection sensor S1 and the second detection sensor S2. Also, the first detection sensor S1 and the second detection sensor S2 are merely an example of a skew detection sensor, and the skew detection sensor may be a single sensor such as a line sensor.

[0037] 1 is disposed downstream in the transport direction D of the multiple sheets of paper P stacked on the stacking table 10, and blows out floating air A2 for floating multiple sheets of paper P (for example, around 10 sheets) including the topmost sheet of paper P1, for example, by operating a fan. Note that the floating air blowing mechanism 50 is not limited to being disposed downstream in the transport direction D of the multiple sheets of paper P stacked on the stacking table 10, and may be disposed on both sides of the width direction W of the sheets of paper P.

[0038] The floating air blowing mechanism 50 has a blocking section 51 that blocks the blowing of at least a portion of the floating air A2. This blocking section 51 can be configured, for example, similar to the blocking section 31 of the suction mechanism 30 that has a shutter 31a or the like. The blocking section 51 of the floating air blowing mechanism 50 is an example of a floating blocking means that blocks the blowing of at least a portion of the air. The blocking section 51 is disposed, for example, at the blowing port of the floating air A2 in the floating air blowing mechanism 50, but may also be disposed in another location, such as near a supply fan (air supply source) not shown.

[0039] The separation air blowing mechanism 60 is disposed downstream in the transport direction D of the multiple sheets of paper P stacked on the stacking table 10, and blows out separation air A3 for separating the uppermost sheet P1 from the second sheet P2 located below it by operating a fan, for example. Note that the separation air blowing mechanism 60 is not limited to being disposed downstream in the transport direction D of the multiple sheets of paper P stacked on the stacking table 10, and may be disposed on both sides of the width direction W of the paper P.

[0040] 2 has a processor (e.g., CPU: Central Processing Unit) that functions as an arithmetic processing device that controls the operation of the entire sheet feeding device 1, and reads and executes a predetermined program, for example, from storage unit 72 or from a storage medium (non-transient computer-readable recording medium) that is detachable from sheet feeding device 1. Control unit 71 controls the operation of each part of sheet feeding device 1 by executing this program. Note that in cases where sheet feeding device 1 is provided integrally with image forming device 101, the control unit of image forming device 101 may also serve as control unit 71 of sheet feeding device 1.

[0041] The storage unit 72 has memories such as a ROM (Read Only Memory), which is a read-only semiconductor memory in which a specific control program is pre-recorded, and a RAM (Random Access Memory), which is a semiconductor memory that can be written to and read at any time and is used as a working memory area as needed when the processor executes various control programs.

[0042] Interface unit 73 transmits and receives various types of information to and from devices such as image forming apparatus 101. For example, interface unit 73 receives information such as a paper feed request or a paper feed stop request from a control unit of image forming apparatus 101, and control unit 71 controls the operation of each unit of paper feeder 1 based on this information.

[0043] The loading platform driving unit 81 has a motor (an example of an actuator) that raises and lowers the loading platform 10.

[0044] The transport mechanism drive unit 82 has a motor (an example of an actuator) that rotates a drive pulley, which is one of the pulleys 22 and 23 of the transport mechanism 20.

[0045] The first registration roller pair drive unit 83 has a motor (an example of an actuator) that rotates the first registration roller pair 41, and the second registration roller pair drive unit 84 has a motor (an example of an actuator) that rotates the second registration roller pair 42.

[0046] Next, the image forming apparatus 101 shown in FIG. 1 will be described.

[0047] Image forming apparatus 101 includes image forming section 110, conveying section 120, first paper feed section 130, second paper feed section 140, third paper feed section 150, and conveying roller pairs 161-167. In Fig. 1, a conveying path continuing from paper feeder 1, first paper feed section 130, second paper feed section 140, and third paper feed section 150 to image forming section 110 is shown by a thick solid line. In this conveying path, paper P may be guided by a pair of upper and lower plate-shaped conveying guides (not shown) except for the portions where roller pairs, sensors, etc. are arranged.

[0048] The image forming unit 110 has, for example, a line-head type inkjet head (not shown) for each color used for printing. The printing method of the image forming unit 110 may be any printing method other than the inkjet printing method.

[0049] The conveying section 120 is disposed so as to face the image forming section 110. The conveying section 120 conveys the paper P, for example, by a conveyor belt while adsorbing the paper P.

[0050] The first paper feed section 130, the second paper feed section 140, and the third paper feed section 150 each include paper feed trays 131, 141, and 151, and paper feed rollers 132, 133, 142, 143, 152, and 153.

[0051] A plurality of sheets of paper P are stacked on the paper feed trays 131, 141, and 151.

[0052] The paper feed rollers 132, 133, 142, 143, 152, and 153 are pairs of feed rollers that feed and transport the uppermost paper P among the multiple sheets of paper P stacked on the paper feed trays 131, 141, and 151.

[0053] The transport roller pairs 161 to 165 are disposed on the transport path between the first paper feed section 130, the second paper feed section 140, and the third paper feed section 150 and the first registration roller pair 41 and the second registration roller pair .

[0054] The pair of conveying rollers 166, 167 are disposed downstream of the first detection sensor S1 and the second detection sensor S2 in the conveying direction D. As shown in Fig. 3, the pair of conveying rollers 166, 167 are disposed side by side in the width direction W perpendicular to the conveying direction D of the paper P so that the positions of the pair of conveying rollers 166, 167 in the conveying direction D of the paper P are the same.

[0055] In the above-described image forming apparatus 101, the paper P printed by the image forming unit 110 is transported to a paper output tray (not shown) and stacked on the paper output tray. When double-sided printing is performed on the paper P, the paper P printed on one side by the image forming unit 110 is transported again to the pair of transport rollers 166, 167 via a circulation path (not shown), and printing is performed again by the image forming unit 110.

[0056] Hereinafter, the paper feeding operation of paper feeding device 1 will be described with reference to FIG. 5, FIG. 6A to FIG. 6D, and FIG.

[0057] First, the explanation begins after the topmost sheet P1 of multiple sheets P stacked on the stacking platform 10 has been adsorbed onto the conveying belt 21 while the suction mechanism 30 is sucking in the suction air A1, the floating air blowing mechanism 50 is blowing in the floating air A2, and the separation air blowing mechanism 60 is blowing in the separation air A3.

[0058] As shown in Fig. 6A, when the topmost sheet P1 is adsorbed to the conveyor belt 21, the control unit 71 stops blowing the floating air A2 from the floating air blowing mechanism 50. The state in which the floating air A2 has stopped is shown by the dashed arrow in Fig. 6A for the floating air blowing mechanism 50. As the blowing of the floating air A2 stops, the second sheet P2 that is not adsorbed to the conveyor mechanism 20 and the sheets P below it fall as shown in Fig. 6A and return to the state where they are stacked on the stacking table 10.

[0059] Furthermore, the control unit 71 controls the drive of the transport mechanism drive unit 82 to start transport of the uppermost sheet P1 by the transport mechanism 20 at transport speed V1 (time t1 in FIG. 5). At this time t1, the control unit 71 controls the first registration roller pair drive unit 83 and the second registration roller pair drive unit 84 to drive the first registration roller pair 41 and the second registration roller pair 42 at the transport speed V1. Also, at time t1, a control unit (not shown) of the image forming apparatus 101 controls the drive units (not shown) to drive the transport roller pairs 166 and 167 at the transport speed V1.

[0060] Then, as shown in FIG. 6B, after the transport of the topmost sheet P1 has begun, the control unit 71 causes the floating air blowing mechanism 50 to resume blowing floating air A2 in order to adsorb the next sheet P (the second sheet P2) to the transport mechanism 20.

[0061] Thereafter, as shown in FIG. 5, if there is a time difference between time t2 when the second detection sensor S2 detects the paper P and time t3 when the first detection sensor S1 detects the paper P, the control unit 71 can determine that the paper P is skewed (the rear side of the paper feeding device 1 is ahead).

[0062] When the control unit 71 determines that the paper P is skewed in this way, for example, at time t3 when the first detection sensor S1 on the front side of the paper feeder 1 detects the paper P later, the control unit 71 drives the second registration roller pair drive unit 84 to reduce the conveying speed V1 of the second registration roller pair 42 on the rear side, where the paper P reaches first, to the conveying speed Va. That is, the control unit 71 adjusts the conveying amount of the paper P by the second registration roller pair 42 on the rear side of the paper feeder 1 to be less than the conveying amount of the paper P by the first registration roller pair 41 on the front side of the paper feeder 1 (the conveying amount is represented by the length of the arrow in FIG. 7), and controls the first registration roller pair 41 and the second registration roller pair 42 (the first registration roller pair drive unit 83 and the second registration roller pair drive unit 84) to correct the skew of the paper P by the first registration roller pair 41 and the second registration roller pair 42. The timing to reduce the conveying speed V1 of the second registration roller pair 42 to the conveying speed Va, i.e., the timing to start the skew correction, is not limited to the detection timing (time t3) of the first detection sensor S1 or the second detection sensor S2 which detects the paper P later, but may be any timing after the timing (time t2) which detects the paper P earlier, or the timing when the control unit 71 determines that the detection is earlier or later than the scheduled detection time of the paper P. In addition, the skew correction of the paper P is preferably performed in a state where the paper P is nipped only by the first registration roller pair 41 and the second registration roller pair 42 before the paper P reaches the conveying roller pairs 166 and 167. In addition, instead of the control to reduce the conveying speed V1 to the conveying speed Va, the skew of the paper P may be corrected by the control to increase the conveying speed V1.

[0063] Then, as shown in FIG. 6C, the control unit 71 controls the blocking unit 31 (suction mechanism 30) to block the suction of the suction air A1 (close the shutter 31a) in a state where the paper P is located between the conveying mechanism 20 and the first and second registration roller pairs 41 and 42 (time t4 in FIG. 5). The state where the suction air A1 is stopped is shown by a dashed arrow in the suction mechanism 30 in FIG. 6C. It is preferable that at least a part of the period (times t4 to t6) during which the suction of the suction air A1 is blocked overlaps with the time when the second registration roller pair 42 is reduced to the conveying speed Va (during skew correction). In addition, after the conveying of the paper P starts, the control unit 71 restarts the blowing of the floating air A2 by the floating air blowing mechanism 50 as shown in FIG. 6C, so that the second paper P2 is attracted to the conveying mechanism 20 immediately after the uppermost paper P1 is conveyed from the conveying mechanism 20.

[0064] In addition, the time t4 at which the suction of the suction air A1 begins to be shut off may be a time after a first specified period (time tA) has elapsed from time t1 at which the conveying mechanism 20, the first registration roller pair 41, the second registration roller pair 42, and the conveying roller pairs 166, 167 start to be driven, or a time after a second specified period (time tB) has elapsed from time t2 at which one of the first detection sensor S1 and the second detection sensor S2 detects the paper P first, or a time after a third specified period (time tC) has elapsed from time t3 at which the other of the first detection sensor S1 and the second detection sensor S2 detects the paper P later, and is not particularly limited.

[0065] Also, as shown in FIG. 6D, the time t6 at which the suction mechanism 30 resumes suction of the suction air A1 is after the time t5 at which the first registration roller pair 41, the second registration roller pair 42, and the conveying roller pairs 166, 167 stop being driven, but may be prior to this drive stop time t5.

[0066] In addition, the suction of the suction air A1 may be cut off (from time t4 to time t6) for all sheets P being transported, or may be cut off only when the first registration roller pair 41 and the second registration roller pair 42 correct the skew of the sheet P (for example, when the detection time difference between the detection time t2 of the first detection sensor S1 and the detection time t3 of the second detection sensor S2 exceeds a threshold value).

[0067] In the above example, the shutter 31a is closed to completely block the suction of the suction air A1 in order to reduce the back tension on the paper P caused by the suction of the suction air A1. However, the amount of blocking of the suction of the suction air A1 may be adjusted, for example, according to the thickness of the paper P. For example, the opening degree of the shutter 31a shown in Fig. 4A and Fig. 4B may be rotated to 60% for thick paper, 40% for standard paper, and 20% for thin paper, as shown in Fig. 8, so that the amount of blocking of the suction air A1 is reduced as the paper P becomes thicker. In this way, by reducing the amount of blocking of the suction air A1 for the thick paper P, which is heavy and easily released from the suction mechanism 30, the blocking can be immediately released and the suction of the next second sheet of paper P2 can be started.

[0068] The amount of suction cutoff of the suction air A1 may be adjusted based on other paper information (one example of medium information) such as the size, material, and surface irregularities, not limited to the thickness of the paper P (medium), or may be adjusted based on environmental information such as temperature, humidity, and airflow detected by a sensor (not shown), or the transport speed of the paper P. That is, the amount of suction cutoff of the suction air A1 may be adjusted based on at least one of the paper information, environmental information, and transport speed. Also, whether or not to cut off the suction of the suction air A1 may be adjusted based on at least one of the paper information, environmental information, and transport speed. Also, the amount of suction cutoff of the suction air A1 may be reduced, for example, as the adsorption of the paper P to the transport mechanism 20 is more easily released (for example, as the weight of the paper P increases or as the paper P becomes uneven).

[0069] In the present embodiment described above, the paper feeder 1, which is an example of a medium supplying device, includes a stacking table 10, a transport mechanism 20, a suction mechanism 30, a first registration roller pair 41 and a second registration roller pair 42, which are an example of skew correction rollers, and a control unit 71. A plurality of sheets of paper P, which are an example of a plurality of media, are stacked on the stacking table 10. The transport mechanism 20 transports the uppermost sheet P1 of the plurality of sheets P stacked on the stacking table 10. The suction mechanism 30 adsorbs the uppermost sheet P1 to the transport mechanism 20 by sucking air (suction air A1). The first registration roller pair 41 and the second registration roller pair 42 receive the sheet P from the transport mechanism 20 and correct the skew of the sheet P. The control unit 71 controls the suction mechanism 30 to cut off suction of at least a portion of the suction air A1 when the paper P is positioned between the conveying mechanism 20 and the first and second registration roller pairs 41 and 42 when at least the first and second registration roller pairs 41 and 42 correct the skew of the paper P.

[0070] In this way, by blocking at least a part of the suction air A1 during skew correction of the paper P, it is possible to suppress the occurrence of wrinkles due to twisting of the paper P in the case of thin paper P, and to suppress the inability to change the orientation of the paper P in the case of thick paper P. Therefore, in this embodiment, skew correction can be performed accurately. In addition, since the paper P is transported while being adsorbed to the transport mechanism 20, a problem that occurs in a mode in which the paper P is nipped and transported by the nip pressure of the roller pair, which is a mode in which adsorption and transport are not performed differently from this embodiment, that is, a problem that the nip pressure of the paper P becomes unstable due to the elasticity of the roller pair or the backlash or springiness of the mechanism that drives the roller pair before and after the nip pressure is released instead of blocking the suction, can be avoided. Therefore, in this embodiment, it is also possible to suppress transport defects such as fluctuations in the transport amount and transport position deviation due to slippage, especially when the paper P is transported at high speed. In addition, in this embodiment, the first registration roller pair 41 and the second registration roller pair 42 correct the skew of the paper P handed over from the transport mechanism 20 that adsorbs and transports the paper P, and therefore transport defects can be suppressed by being less susceptible to the effect of variations in the height of the topmost paper P1 stacked on the stacking table 10. Therefore, according to this embodiment, skew correction can be performed accurately and transport defects of the paper P (medium) can be suppressed.

[0071] In addition, in this embodiment, the control unit 71 controls the first registration roller pair 41 and the second registration roller pair 42 to adjust the transport amount of the paper P on one side and the other side in the width direction W perpendicular to the transport direction D of the paper P.

[0072] However, unlike the present embodiment, in an aspect using a skew correction roller that corrects skew of paper P by being abutted against it, if the suction of the suction air A1 is cut off, the slack caused by the abutment of the paper P cannot be sufficiently formed, and skew correction cannot be performed reliably. On the other hand, in the present embodiment, skew correction can be performed more reliably by adjusting the transport amount of the paper P on one side and the other side in the width direction W. Also, in the present embodiment, transport stop due to the abutment of the paper P can be avoided, and transport efficiency can be improved.

[0073] Furthermore, in this embodiment, the control unit 71 controls the suction mechanism 30 based on paper information of the paper P (an example of medium information) so as to adjust the amount of suction blocking of at least a portion of the suction air A1.

[0074] As a result, for heavy paper P or other paper P that is easily released from the transport mechanism 20, the amount of suction blocking is reduced, and the state is set so that the blocking can be released immediately, so that the next sheet of paper P can be immediately attracted to the transport mechanism 20. Therefore, the transport efficiency can be improved.

[0075] The present invention is not limited to the above-described embodiment as it is, and the components can be modified and embodied without departing from the gist of the invention in the implementation stage. In addition, various inventions can be formed by appropriate combinations of the multiple components disclosed in the above-described embodiment. For example, all the components shown in the embodiment may be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention. The invention described in the claims at the time of filing of this application is appended below.

[0076] [Appendix 1] a loading platform on which a plurality of media are loaded; a transport mechanism that transports a topmost medium among the plurality of media stacked on the stacking platform; a suction mechanism that sucks air to adsorb the topmost medium to the transport mechanism; a skew correction roller that receives the medium from the transport mechanism and corrects skew of the medium; a control unit that controls the suction mechanism to cut off suction of at least a portion of air in a state in which the medium is positioned between the transport mechanism and the skew correction roller when the skew correction roller corrects skew of the medium; A medium supplying device comprising:

[0077] [Appendix 2] The control unit controls the skew correction roller to adjust the transport amount of the medium on one side and the other side in a width direction perpendicular to a transport direction of the medium. 2. A medium supplying device according to claim 1.

[0078] [Appendix 3] The control unit controls the suction mechanism to adjust an amount of blocking of suction of the at least a portion of the air based on medium information of the medium. 3. A medium supplying device according to claim 1 or 2. [Explanation of symbols]

[0079] 1 Paper feeder 10 Loading platform 20 Conveyor mechanism 21 Conveyor belt 22,23 Pulley 30 Suction mechanism 31 Breaking section 31a Shutter 31a-1 Blade section 31b Opening material 31b-1 Through hole 31c Rotating shaft member 41 first registration roller pair 42 Second registration roller pair 50 Floating air blowing mechanism 51 Breaking section 60 Separation air blowing mechanism 71 Control Unit 72 Memory section 73 Interface section 81 Loading platform drive unit 82 Transport mechanism drive unit 83 First registration roller pair driving section 84 Second registration roller pair driving section 100 Image forming system 101 Image forming device 110 Image forming section 120 Conveyor 130 1st paper feed section 140 2nd paper feed section 150 3rd paper feed section 131,141,151 Paper Tray 132,133,142,143,152,153 Paper feed roller 161~167 Transport roller pair A1 Suction air A2 Floating Air A3 Separation Air D Conveying direction P paper S1 First detection sensor S2 Second detection sensor W Width direction

Claims

1. a loading platform on which a plurality of media are loaded; a transport mechanism that transports a topmost medium among the plurality of media stacked on the stacking platform; a suction mechanism that sucks air to adsorb the topmost medium to the transport mechanism; a skew correction roller that receives the medium from the transport mechanism and corrects skew of the medium; a control unit that controls the suction mechanism to cut off suction of at least a portion of air in a state in which the medium is positioned between the transport mechanism and the skew correction roller when the skew correction roller corrects skew of the medium; A medium supplying device comprising:

2. The control unit controls the skew correction roller to adjust the transport amount of the medium on one side and the other side in a width direction perpendicular to a transport direction of the medium.

2. The medium supply device according to claim 1.

3. The control unit controls the suction mechanism to adjust an amount of blocking of suction of the at least a portion of the air based on medium information of the medium.

3. The medium supply device according to claim 1 or 2.

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