Sheet conveying device

Abstract

To provide a sheet conveyance device which enables miniaturization.SOLUTION: A sheet conveyance device comprises a tray, a pickup roller, a lifting mechanism, a holder, a biasing part, and a detection mechanism. The lifting mechanism causes the tray to ascend and descend to a lifted position and a lowered position. The lifted position is a position where a sheet is in contact with the pickup roller. The holder holds the pickup roller, so as to be displaceable by pushing up the sheet. The biasing part adds a biasing force in a direction in which the pickup roller is pushed down to the holder. The detection mechanism detects that the sheet has pushed up the pickup roller. The detection mechanism comprises a detection part and a sensor. The detection part can switch between a reference position and a detection position, by a displacement of the holder with lifting / lowering of the tray. The sensor detects that the detection part has arrived at the detection position. The biasing part adds the biasing force to the holder at the position overlapping with the pickup roller when viewed from the direction of the biasing force.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a sheet transport device. [Background technology]

[0002] Image processing devices have a sheet transport device. The sheet transport device has a tray on which multiple sheets are stacked, a pickup roller, and a lifting mechanism that raises part of the tray. The sheet transport device may use a detection mechanism that detects when the tray is raised and the sheet reaches the pickup roller. There is a demand for miniaturization of the sheet transport device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-220972 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a sheet transport device that can be made compact. [Means for solving the problem]

[0005] A sheet conveying device according to an embodiment includes a tray, a pickup roller, a lifting mechanism, a holder, an urging unit, and a detection mechanism. The tray holds multiple sheets. The pickup roller conveys the sheets on the tray. The lifting mechanism raises and lowers the tray to an elevated position and a lowered position. The elevated position is a position where the sheet contacts the pickup roller. The lowered position is a position lower than the elevated position. The holder holds the pickup roller so that it can be displaced by the sheet pushing it up. The urging unit applies a urging force to the holder in a direction that presses down the pickup roller. The detection mechanism detects when the sheet pushes up the pickup roller. The detection mechanism includes a detection unit and a sensor. The detection unit is capable of switching between a reference position and a detection position based on the displacement of the holder accompanying the elevation of the tray. The sensor detects when the detection unit reaches the detection position. The biasing portion applies the biasing force to the holder at a position overlapping the pickup roller when viewed from the direction of the biasing force. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of an image processing apparatus using a sheet conveying apparatus according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a sheet conveying device according to a first embodiment. [Figure 3] FIG. 2 is a perspective view of a portion of the sheet conveying device according to the first embodiment. [Figure 4] FIG. 2 is a perspective view of a portion of the sheet conveying device according to the first embodiment. [Figure 5] FIG. 2 is a perspective view of a portion of the sheet conveying device according to the first embodiment. [Figure 6] FIG. 2 is an enlarged perspective view of a portion of the sheet conveying device according to the first embodiment. [Figure 7] 5A to 5C are diagrams illustrating the operation of the sheet conveying device according to the first embodiment. [Figure 8] FIG. 2 is a perspective view of a main body of the image processing apparatus to which a biasing unit is attached. [Figure 9]FIG. 2 is a perspective view of the main body of the image processing apparatus from which the urging unit is removed. [Figure 10] FIG. 10 is a perspective view of a portion of a sheet conveying device according to a second embodiment. [Figure 11] 10A to 10C are diagrams illustrating the operation of a sheet conveying device according to a second embodiment. [Figure 12] FIG. 10 is a perspective view of a portion of a sheet conveying device according to a third embodiment. [Figure 13] 10A to 10C are diagrams illustrating the operation of a sheet conveying device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a sheet conveying device according to an embodiment will be described with reference to the drawings. In the following drawings, unless otherwise specified, the same or corresponding components are designated by the same reference numerals.

[0008] (First embodiment) A sheet conveying device according to a first embodiment will be described. FIG. 1 is a schematic diagram showing an example of the configuration of an image processing apparatus using a sheet conveying device according to the first embodiment.

[0009] As shown in FIG. 1, the image processing apparatus 100 includes a control panel 1, a scanner unit 2, a printer unit 3, a sheet supply unit 4, a conveying unit 5, a manual feed unit 10 (sheet conveying device), and a control circuit 60.

[0010] Hereinafter, when referring to relative positions in the image processing device 100, the Xp direction, Xm direction, Yp direction, Ym direction, Zp direction, and Zm direction shown in the figures may be used. The Xp direction is the direction from left to right when standing in front of the image processing device 100 (the front side of the paper in FIG. 1). The Xm direction is the opposite direction to the Xp direction. The Yp direction is the direction from the back to the front of the image processing device 100. The Ym direction is the opposite direction to the Yp direction. The Zp direction is the vertically upward direction. The Zm direction is the vertically downward direction. When the orientation of the Xp (Yp, Zp) direction and the Xm (Ym, Zm) direction does not matter or when both directions are included, they will simply be referred to as the X (Y, Z) direction. Hereinafter, a plane having a normal in the X direction will be referred to as a YZ plane, a plane having a normal in the Y direction as a ZX plane, and a plane having a normal in the Z direction as an XY plane. The ZX plane is parallel to the conveyance direction of a sheet S, which will be described later, in the image processing device 100. The XY plane is a horizontal plane.

[0011] The control panel 1 operates the image processing device 100 in response to user operations. The scanner unit 2 reads image information of an object to be copied as light and dark, and outputs the read image information to the printer unit 3.

[0012] The printer unit 3 forms an image on the sheet S based on image information from the scanner unit 2 or from an external source. The printer unit 3 forms an output image (toner image) using a developer containing toner. The printer unit 3 transfers the toner image onto the surface of the sheet S. The printer unit 3 applies heat and pressure to the toner image on the surface of the sheet S to fix the toner image to the sheet S.

[0013] The sheet supply unit 4 supplies the sheets S to the printer unit 3 one by one in accordance with the timing when the printer unit 3 forms a toner image. The sheet supply unit 4 has a plurality of paper feed cassettes 20 and a plurality of cassette paper feed units 21. The plurality of paper feed cassettes 20 accommodate sheets S of various sizes. In the example shown in Fig. 1, the plurality of paper feed cassettes 20 are provided in three stages. The cassette paper feed units 21 are arranged above the ends in the Xp direction of the respective paper feed cassettes 20. Each cassette paper feed unit 21 has a pickup roller 212 (conveyance roller), a paper feed roller 211, and a separation roller 213.

[0014] The pickup roller 212 conveys the sheets S required for image formation from the paper feed cassette 20 to a nip portion between the paper feed roller 211 and the separation roller 213. The pickup roller 212 is an example of a conveying roller that conveys the multiple sheets S from the upper side in the stacking direction in the conveying direction. The sheet feed roller 211 conveys the sheet S conveyed to the nip portion to the conveying portion 5. The separation roller 213 separates one sheet S from the other when a plurality of sheets S are conveyed.

[0015] The conveying section 5 has a conveying roller 23 and a registration roller 24. The conveying section 5 conveys the sheet S supplied from the sheet supplying section 4 to the registration roller 24. The registration rollers 24 transport the sheet S in accordance with the timing at which the printer unit 3 transfers the toner image onto the sheet S.

[0016] The conveying roller 23 abuts the leading edge of the sheet S in the conveying direction against the nip N of the registration roller 24. The conveying roller 23 bends the sheet S to adjust the position of the leading edge of the sheet S in the conveying direction. The registration rollers 24 align the leading edge of the sheet S sent out from the conveyance rollers 23 at the nip N. Furthermore, the registration rollers 24 convey the sheet S to a transfer unit 28 side, which will be described later. The transport unit 5 has transport paths 301, 302, 303, and 304. The transport paths 301, 302, 303, and 304 will be explained after the other components of the printer unit 3 have been explained.

[0017] The printer section 3 has a plurality of image forming sections 25, a plurality of exposure sections 26, an intermediate transfer belt 27, a transfer section 28, a fixing unit 29, and a transfer belt cleaning unit 35.

[0018] The plurality of image forming units 25 are arranged in a four-unit array in the Xp direction. Each of the plurality of image forming units 25 forms a toner image to be transferred onto the sheet S on the intermediate transfer belt 27. Each of the plurality of image forming units 25 has a photosensitive drum 7. The plurality of image forming units 25 form yellow, magenta, cyan, and black toner images on the respective photosensitive drums 7. A charger, a developing unit 8, a primary transfer roller, a cleaning unit, and a static eliminator are arranged around each photosensitive drum 7. The primary transfer roller faces the photosensitive drum 7. An intermediate transfer belt 27 is sandwiched between the primary transfer roller and the photosensitive drum 7. An exposure unit 26 is arranged below the charger and the developing unit 8.

[0019] A toner cartridge 33 is disposed above each image forming unit 25. Each toner cartridge 33 contains a different color of toner. The four toner cartridges 33 contain yellow, magenta, cyan, and black toner, respectively. The toner in each toner cartridge 33 is supplied to the image forming unit 25 below it through a toner supply pipe (not shown).

[0020] The exposure unit 26 irradiates the charged surface of each photosensitive drum 7 with laser light. The laser light is controlled based on image information. The exposure unit 26 may also be configured to irradiate LED light instead of laser light. In the example shown in FIG. 1, the exposure unit 26 is disposed below the multiple image forming units 25. The exposure section 26 is supplied with image information corresponding to yellow, magenta, cyan, and black, respectively. The exposure unit 26 forms an electrostatic latent image on the surface of each photosensitive drum 7 based on image information.

[0021] The intermediate transfer belt 27 is an endless belt. Tension is applied to the intermediate transfer belt 27 by multiple rollers that are in contact with the inner circumferential surface. The intermediate transfer belt 27 is stretched flat. The inner circumferential surface of the intermediate transfer belt 27 abuts against the support roller 281 at the furthest position in the Xp direction in the tensioning direction. The inner circumferential surface of the intermediate transfer belt 27 abuts against the transfer belt roller 32 at the furthest position in the Xm direction in the tensioning direction. The support roller 281 forms part of the transfer unit 28, which will be described later. The support roller 281 guides the intermediate transfer belt 27 to the secondary transfer position. The transfer belt roller 32 guides the intermediate transfer belt 27 to a cleaning position.

[0022] The image forming units 25, excluding the primary transfer roller, are arranged in the Xp direction on the lower surface side of the intermediate transfer belt 27. The image forming units 25 are arranged at intervals in the region between the transfer belt roller 32 and the support roller 281. When the toner image reaches the primary transfer position, a transfer bias is applied to the primary transfer roller of each image forming unit 25. Each primary transfer roller transfers the toner image on the surface of each photosensitive drum 7 onto the intermediate transfer belt 27 (primary transfer).

[0023] On the intermediate transfer belt 27, a transfer unit 28 is disposed at a position closest to the image forming unit 25 in the Xp direction. Transfer unit 28 has a support roller 281 and a secondary transfer roller 282. Secondary transfer roller 282 and support roller 281 sandwich intermediate transfer belt 27. The position where secondary transfer roller 282 and intermediate transfer belt 27 come into contact with each other is the secondary transfer position. The transfer unit 28 transfers the charged toner image on the intermediate transfer belt 27 onto the surface of the sheet S at the secondary transfer position. The transfer unit 28 applies a transfer bias to the secondary transfer position. The transfer unit 28 transfers the toner image on the intermediate transfer belt 27 onto the sheet S by the transfer bias.

[0024] The fixing device 29 applies heat and pressure to the sheet S. The fixing device 29 fixes the toner image transferred to the sheet S by the heat and pressure. The fixing device 29 is disposed above the transfer unit . The transfer belt cleaning unit 35 faces the transfer belt roller 32. The transfer belt cleaning unit 35 sandwiches the intermediate transfer belt 27. The transfer belt cleaning unit 35 scrapes off toner on the surface of the intermediate transfer belt 27.

[0025] Conveyance paths 301 and 302 for conveying the sheet S from below upward are formed between the registration rollers 24 and the transfer unit 28, and between the transfer unit 28 and the fixing unit 29, in this order. A conveyance path 303 for discharging the sheet S in the horizontal direction is formed between the fixing unit 29 and the paper discharge outlet. Above the fixing device 29, a conveying direction switching unit 31 that switches the conveying direction of the sheet S is provided. Inside the printer unit 3, on the Xp direction side of the conveying paths 301 and 302, a conveying path 304 is formed to convey the sheet S from the conveying direction switching unit 31 on the fixing unit 29 to the registration rollers 24. The conveying path 304 is used, for example, when performing double-sided printing, to turn over the sheet S with an image formed on its front side and feed it to the registration rollers 24. The conveying paths 301, 302, 303, and 304 each have a conveying guide portion that faces each other with the sheet S sandwiched therebetween, and a conveying roller that is provided as needed.

[0026] The manual feed unit 10 supplies a sheet S on which an image is to be formed to the printer section 3. The manual feed unit 10 is an example of a sheet conveying device. The manual feed unit 10 has a manual paper feed section 11, a manual feed tray 12, a lifting mechanism 40, a holder 114 (see FIG. 2), a biasing section 115 (see FIG. 2), and a tray-up detection mechanism 116 (see FIG. 2).

[0027] The manual paper feed unit 11 has a pickup roller 112 (conveying roller), a paper feed roller 111, and a separation roller 113. The manual paper feed unit 11 separates and feeds the sheet S placed on the manual tray 12, and conveys the sheet S toward the registration rollers 24.

[0028] The pickup roller 112 has a configuration similar to that of the pickup roller 212 in the cassette paper feed unit 21. The paper feed roller 111 has a configuration similar to that of the paper feed roller 211 in the cassette paper feed unit 21. The separation roller 113 has a configuration similar to that of the separation roller 213 in the cassette paper feed unit 21. The pickup roller 112 is an example of a conveying roller that conveys the sheet S from the upper side in the stacking direction in the conveying direction.

[0029] The manual feed tray 12 can rotate about an axis along the Y direction. When using the manual feed tray 12, the manual feed tray 12 is opened by rotating it clockwise in FIG. 1 as shown by the solid line. Sheets S of various sizes can be placed on the open manual feed tray 12. When the manual feed tray 12 is not in use, the manual feed tray 12 is rotated counterclockwise in FIG. 1 as indicated by the two-dot chain line and accommodated in the side of the printer unit 3 in the Xp direction.

[0030] Fig. 2 is a perspective view of the manual feed unit 10. Fig. 3 is a perspective view of a portion of the manual feed unit 10. Fig. 4 is a perspective view of a portion of the manual feed unit 10. Fig. 5 is a perspective view of a portion of the manual feed unit 10. Fig. 6 is an enlarged perspective view of a portion of the manual feed unit 10.

[0031] As shown in FIG. 2, the manual tray 12 has a main body 121, a lift plate 13 (tray), and a biasing member . The main body 121 is formed in a plate shape. The lift plate 13 is provided on the main body 121. The upper surface of the lift plate 13 is a placement surface on which the sheets S are placed. The lift plate 13 is an example of a tray on which a plurality of sheets S are stacked.

[0032] The main body 121 is provided with a support portion 123 that rotatably supports the lift plate 13. The support portion 123 is disposed on an axis C1. The axis C1 is parallel to the Y direction. The lift plate 13 is rotatably engaged with the support portion 123. The lift plate 13 is rotatable around the axis C1.

[0033] As shown in FIG. 1, the lifting mechanism 40 is provided in the main body of the printer unit 3. The lifting mechanism 40 raises and lowers the lifting plate 13 about the axis C1 in the open manual tray 12 between an elevated position and a lowered position (see FIG. 2). The elevated position is the position where the tip of the lifting plate 13 is farthest from the main body 121. In the elevated position, the sheet on the lifting plate 13 comes into contact with or close to the pickup roller 112. The lowered position is the position where the tip of the lifting plate 13 is closest to the main body 121. The lowered position is a position lower than the elevated position. The lifting mechanism 40 can raise and lower the lifting plate 13 by, for example, a drive motor.

[0034] As shown in FIG. 3, holder 114 rotatably holds pickup roller 112. Holder 114 includes an upper plate 114a, a first end plate 114b, and a second end plate 114c. Upper plate 114a is rectangular when viewed in the Z direction. A protrusion 114d that protrudes in the Zp direction is formed on the upper surface of upper plate 114a. The tip of pressing body 131 can abut against protrusion 114d. Holder 114 is pressed downward by pressing body 131 at protrusion 114d.

[0035] The portion (protrusion 114d) where the tip of pressing body 131 contacts holder 114 is on the ZX plane including pickup roller 112, and overlaps pickup roller 112 when viewed from the direction of the biasing force (Z direction). It is preferable that at least a portion of the contact portion of pressing body 131 is on the ZX plane including pickup roller 112. It is even more preferable that the contact portion of pressing body 131 overlaps pickup roller 112 when viewed from the Z direction.

[0036] The first end plate 114b hangs down from the Yp-direction end of the upper plate 114a. The second end plate 114c hangs down from the Ym-direction end of the upper plate 114a. The first end plate 114b and the second end plate 114c are aligned along the ZX plane.

[0037] First end plate 114b and second end plate 114c are formed with bearings 114e that rotatably support rotation shaft 112A of pickup roller 112. Rotation shaft 112A of pickup roller 112 extends along the Y direction.

[0038] The holder 114 is supported on the device body of the printer unit 3 by a holder shaft 120 that extends along the Y direction. The holder 114 is rotatable around an axis C2 of the holder shaft 120 (see FIG. 4). When viewed from the Y direction, the holder shaft 120 is located away from the rotation axis 112A of the pickup roller 112. The holder 114 can displace the pickup roller 112 by rotating around the axis C2 of the holder shaft 120. The holder 114 can change the height position of the pickup roller 112 by rotating around the axis C2 (see FIGS. 7(A) and 7(B)).

[0039] As shown in FIGS. 4 and 5, biasing portion 115 applies a force to holder 114 in a direction that presses pickup roller 112 downward. The biasing portion 115 includes a pressing body 131 , a biasing member 132 , and a support portion 133 . 5, the pressing body 131 includes a main body portion 131a and a flange portion 131b. The pressing body 131 is displaceable in the longitudinal direction of the main body portion 131a. The main body portion 131a is formed in a rod shape having a length in the Z direction. The main body portion 131a is inserted into the biasing member 132.

[0040] The flange portion 131b protrudes radially outward from the main body portion 131a at a longitudinal intermediate portion of the main body portion 131a. The flange portion 131b has a plate shape that is perpendicular to the longitudinal direction of the main body portion 131a. The lower end of the biasing member 132 can be locked to the flange portion 131b.

[0041] The biasing member 132 is fitted onto the main body portion 131a. The lower end of the biasing member 132 engages with the upper surface of the flange portion 131b. The biasing member 132 is, for example, a coil spring. The biasing member 132 applies a force to the flange portion 131b in a direction approaching the holder 114. The pressing body 131 is biased in a direction approaching the holder 114.

[0042] 4, the support portion 133 includes a base plate 133a, a first locking portion 133b, and a second locking portion 133c. The base plate 133a is plate-shaped and extends along the YZ plane. The first locking portion 133b is plate-shaped and extends along the XY plane. The flange portion 131b of the pressing body 131 can be locked to the upper surface of the first locking portion 133b.

[0043] The second locking portion 133c is located at a position separated from the first locking portion 133b in the Zp direction. The second locking portion 133c is plate-shaped and extends along the XY plane. The upper end of the biasing member 132 can be engaged with the lower surface of the second locking portion 133c. The biasing member 132 applies a force to the flange portion 131b in a direction toward the holder 114, taking a reaction force from the second locking portion 133c.

[0044] 5, the tray-up detection mechanism 116 includes an operation unit 141, an actuator 142, a detection unit 143, and a sensor 144. The tray-up detection mechanism 116 is an example of a "detection mechanism." The tray-up detection mechanism 116 detects that the sheet S has pushed up the pickup roller 112.

[0045] The operating portion 141 extends in the Yp direction from the outer surface (the surface in the Yp direction) of the first end plate 114b. The operating portion 141 has a long plate shape having a length in the Yp direction. For example, the operating portion 141 is curved around the axis C2 of the holder shaft 120 (see FIG. 4).

[0046] 6, the actuator 142 includes a shaft portion 142a and a cam plate portion 142b. The shaft portion 142a has a length in the Y direction. The actuator 142 is rotatable around an axis C3 of the shaft portion 142a. The cam plate portion 142b protrudes radially outward from the outer peripheral surface of the shaft portion 142a. The cam plate portion 142b is shaped like a plate that is perpendicular to the longitudinal direction of the shaft portion 142a. The outer surface of the cam plate portion 142b is a cam surface 142c.

[0047] 5, the detection unit 143 protrudes radially outward from the outer circumferential surface of the shaft 142a. The detection unit 143 is shaped like a plate that is perpendicular to the longitudinal direction of the shaft 142a. The detection unit 143 rotates in the same direction as the actuator 142 in conjunction with the actuator 142. By rotating in conjunction with the actuator 142, the detection unit 143 can switch between a reference position and a detection position.

[0048] For example, a photointerrupter is used as sensor 144. Sensor 144 has a light-emitting portion 144a and a light-receiving portion 144b. Light-emitting portion 144a and light-receiving portion 144b face each other. When detecting portion 143 is in the reference position, detecting portion 143 does not block the detection light of sensor 144. When detecting portion 143 rotates together with actuator 142 and reaches the detection position, detecting portion 143 blocks the detection light. When the detection light is blocked, sensor 144 sends a detection signal to control circuit 60 (see FIG. 1).

[0049] Next, a description will be given of the operation of the image processing device 100. First, a printing operation will be described. As shown in FIG. 1, in the image processing device 100, conditions such as the type of sheet S on which an image is to be formed and the number of prints are set based on the operation of a control panel 1 or an external signal. Image formation is started by a print start signal. Image information is read by a scanner unit 2 from an object to be copied and sent to a printer unit 3, or is sent to the printer unit 3 from an external source. The printer unit 3 supplies a sheet S from a sheet supply unit 4 or a sheet S from a manual feed unit 10 to registration rollers 24 based on a control signal generated by a control circuit 60 in response to the condition setting and receipt of the print start signal. The following describes an example in which a sheet S is supplied from the manual feed unit 10. Setting of a sheet S in the manual feed unit 10 will be described later. Upon receiving the print start signal, the control circuit 60 performs control to start paper feeding from the manual feed unit 10 and image formation.

[0050] Each image forming unit 25 forms an electrostatic latent image on each photosensitive drum 7 based on image information corresponding to each color. Each electrostatic latent image is developed by a corresponding developing device 8. As a result, a toner image corresponding to the electrostatic latent image is formed on the surface of each photosensitive drum 7. Each toner image is primarily transferred by each transfer roller onto intermediate transfer belt 27. As intermediate transfer belt 27 moves, each toner image is superimposed in order without color misregistration, and is sent to transfer unit . The sheet S is fed from the registration rollers 24 to the transfer unit 28. The toner image that has reached the transfer unit 28 is secondarily transferred onto the sheet S. The secondarily transferred toner image is fixed onto the sheet S by a fixing device 29. An image is formed on the sheet S.

[0051] Next, the operation of the manual feeding unit 10 will be described. The user places the required number of sheets S on the lift plate 13 (see FIG. 2) of the manual feed tray 12 (see FIG. 1). When the lift plate 13 (see FIG. 2) reaches the raised position, the sheet S comes into contact with the pickup roller 112 (see FIG. 3), and a force is applied to the pickup roller 112 in the pushing up direction.

[0052] 7(A) and 7(B), when pickup roller 112 (see FIG. 5) is pushed up, holder 114 rotates around axis C2 of holder shaft 120, and protrusion 114d pushes up pressing body 131. When pressing body 131 is pushed up, urging member 132 is compressed. Pressing body 131 applies a force to holder 114 in a downward direction due to the elastic force of urging member 132.

[0053] As shown in Fig. 5, when the holder 114 rotates around the axis C2 of the holder shaft 120, the operating part 141 also rotates around the axis C2. As shown in Fig. 6, the operating part 141 abuts against the cam surface 142c of the cam plate part 142b, causing the actuator 142 to rotate around the axis C3. The detector 143 rotates together with the actuator 142 and moves from the reference position to the detection position.

[0054] When the detection unit 143 reaches the detection position, it blocks the detection light of the sensor 144. The sensor 144 detects that the detection unit 143 has reached the detection position. The sensor 144 sends a detection signal to the control circuit 60 (see FIG. 1). As shown in FIG. 1, the control circuit 60 sends a control signal to each component of the image processing device 100 to transport the sheet S from the manual feed tray 12 to the transport unit 5 and perform the above-mentioned printing operation.

[0055] Fig. 8 is a perspective view of the device main body 100a of the image processing device 100 to which the urging unit 115 is attached. Fig. 9 is a perspective view of the device main body 100a from which the urging unit 115 has been removed. As shown in Fig. 8, the urging unit 115 can be attached to the device main body 100a. As shown in Fig. 9, the urging unit 115 is preferably detachable from the device main body 100a. If the urging unit 115 is detachable from the device main body 100a, maintenance becomes easier. If the urging unit 115 is detachable from the device main body 100a, it becomes easy to change the specifications of the manual feeding unit 10 by replacing the urging member 132, etc.

[0056] In manual feed unit 10, urging unit 115 applies a urging force to holder 114 on the ZX plane including pickup roller 112, so the structure of manual feed unit 10 can be simplified compared to when the urging unit and pickup roller are far apart. Also, because urging unit 115 applies a urging force to holder 114 at a position that overlaps with pickup roller 112 when viewed from the direction of the urging force (Z direction), the structure of manual feed unit 10 can be simplified compared to when the urging unit and pickup roller are far apart. Because manual feed unit 10 has a simple structure, it is advantageous in terms of size and space savings.

[0057] Since biasing unit 115 applies a biasing force to holder 114 on the ZX plane including pickup roller 112, the biasing force of pressing body 131 is efficiently transmitted to pickup roller 112. In addition, since the biasing force is applied to holder 114 at a position overlapping with pickup roller 112 when viewed from the direction of the biasing force (Z direction), the biasing force of pressing body 131 is efficiently transmitted to pickup roller 112.

[0058] The tray-up detection mechanism 116 includes an operation unit 141 and an actuator 142. The actuator 142 can switch between a reference position and a detection position of the detection unit 143. The detection unit 143 can be switched between the reference position and the detection position by the operation of the actuator 142, so that the detection unit 143 can be operated reliably and malfunctions can be suppressed.

[0059] Since the detector 143 is provided on the shaft 142a of the actuator 142, the detector 143 can be reliably operated.

[0060] The biasing portion 115 includes a pressing body 131, a biasing member 132, and a support portion 133. The biasing portion 115 has a simple structure, and therefore can be made smaller.

[0061] (Second embodiment) A sheet conveying device according to a second embodiment will be described. FIG. 10 is a perspective view of a part of the sheet conveying device of the second embodiment.

[0062] As shown in FIG. 10, the manual feeding unit 210 has a tray-up detection mechanism 216 instead of the tray-up detection mechanism 116 . The tray-up detection mechanism 216 includes a detection unit 243 and a sensor 244. The tray-up detection mechanism 216 is an example of a "detection mechanism."

[0063] The detector 243 has the same configuration as the operation unit 141 (see FIG. 3) in the manual feed unit 10 of the first embodiment. When the holder 114 rotates around the axis C2, the detector 243 also rotates around the axis C2. For example, the sensor 244 is a photointerrupter having a light emitting portion 144a and a light receiving portion 144b.

[0064] 11(A) and 11(B), when pickup roller 112 (see FIG. 10) is pushed up, holder 114 rotates around axis C2 of holder shaft 120, and protrusion 114d pushes up pressing body 131. Pressing body 131 applies a force to holder 114 in a downward direction by biasing member 132.

[0065] As the holder 114 rotates around the axis C2, the detection unit 243 also rotates around the axis C2. The detection unit 243 moves from the reference position to the detection position. When the detection unit 243 reaches the detection position, it blocks the detection light of the sensor 244. The sensor 244 sends a detection signal to the control circuit 60 (see FIG. 1). As shown in FIG. 1, the control circuit 60 sends a control signal to each component of the image processing device 100 to transport the sheet S from the manual feed tray 12 to the transport unit 5 and perform the above-mentioned printing operation.

[0066] The manual feeding unit 210 has a simple structure with fewer components for the tray-up detection mechanism 216. The manual feeding unit 210 has an advantage in terms of size and space saving because of its simple structure.

[0067] (Third embodiment) A sheet conveying device according to a third embodiment will be described. FIG. 12 is a perspective view of a part of the sheet conveying device of the second embodiment.

[0068] As shown in FIG. 12, the manual feeding unit 310 has a tray-up detection mechanism 316 instead of the tray-up detection mechanism 116 . The tray-up detection mechanism 316 includes a detection unit 343 and a sensor 344. The tray-up detection mechanism 316 is an example of a "detection mechanism."

[0069] The detection portion 343 is provided at the upper end of the pressing body 131. The detection portion 343 is plate-shaped and extends along the ZX plane. The detection portion 343 protrudes radially outward from the outer circumferential surface of the main body 131a. The detection portion 343 moves up and down together with the pressing body 131. For example, the sensor 344 is a photointerrupter having a light emitting portion 144a and a light receiving portion 144b.

[0070] 13(A) and 13(B), when pickup roller 112 is pushed up, holder 114 rotates around axis C2 of holder shaft 120, and protrusion 114d pushes up pressing body 131. Pressing body 131 applies a force to holder 114 in a downward direction by biasing member 132.

[0071] As the pressing body 131 rises, the detection unit 343 moves from the reference position to the detection position. When the detection unit 343 reaches the detection position, it blocks the detection light of the sensor 344. The sensor 344 sends a detection signal to the control circuit 60 (see FIG. 1). As shown in FIG. 1, the control circuit 60 sends a control signal to each component of the image processing device 100 to transport the sheet S from the manual feed tray 12 to the transport unit 5 and perform the above-mentioned printing operation.

[0072] In manual feed unit 310, since detection unit 343 and sensor 344 are located close to holder 114, manual feed unit 310 can be made smaller.

[0073] According to at least one embodiment described above, the biasing unit applies a biasing force to the holder on a plane that is parallel to the direction of the biasing force and includes the pickup roller, thereby simplifying the structure of the sheet conveying device. The simple structure of the sheet conveying device is advantageous in terms of miniaturization and space-saving. Furthermore, according to at least one embodiment described above, the biasing unit applies a biasing force to the holder at a position that overlaps with the pickup roller when viewed from the direction of the biasing force, thereby simplifying the structure of the sheet conveying device. The simple structure of the sheet conveying device is advantageous in terms of miniaturization and space-saving.

[0074] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0075] 10, 210, 310... manual feeding unit (sheet conveying device), 13... lifting plate (tray), 100... image processing device, 100a... device main body, 112... pickup roller, 114... holder, 115... urging section, 116, 216, 316... tray up detection mechanism (detection mechanism), 131... pressing body, 132... urging member, 133... support section, 141... operation section, 142... actuator, 142a... shaft section, 143, 243, 343... detection section, 144, 244, 344... sensor, S... sheet

Claims

1. a tray on which a plurality of sheets are stacked; a pickup roller for conveying the sheet on the tray; a lifting mechanism that lifts and lowers the tray to an elevated position where the sheet contacts the pickup roller and a lowered position that is lower than the elevated position; a holder that holds the pickup roller so that the pickup roller can be displaced by being pushed up by the sheet; a biasing section that applies a biasing force to the holder in a direction that presses down the pickup roller; and a detection mechanism that detects that the sheet has pressed up the pickup roller. Equipped with The detection mechanism includes: a detection unit that can switch between a reference position and a detection position in response to displacement of the holder caused by lifting and lowering of the tray; a sensor that detects that the detection unit has reached the detection position; Equipped with the biasing portion applies the biasing force to the holder at a position overlapping the pickup roller when viewed from the direction of the biasing force; The detection mechanism includes an operation portion protruding from the holder; an actuator having the detection unit; Furthermore, the actuator is operated by movement of the operation unit accompanying displacement of the holder, and switches the detection unit between the reference position and the detection position; the actuator includes a shaft portion that is rotatable about an axis; The detection portion is formed to protrude from the outer circumferential surface of the shaft portion. Sheet transport device.

2. The biasing portion includes a pressing body that applies the biasing force to the holder; a biasing member that biases the pressing body in a direction toward the holder; a support portion that supports the pressing body and the biasing member, The sheet transport device according to claim 1 .

3. the biasing unit is detachable from the main body of the image processing device; 3. The sheet conveying device according to claim 1.

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