Embodiments described herein relate generally to an image forming apparatus and a sheet handling mechanism.
An image forming apparatus is provided with a sheet feed unit such as a manual sheet feed. The sheet feed unit includes an elevating plate that pushes up the sheet placed on the sheet tray from below to the position of the pickup roller. The elevating plate is ascended and descended by a movable portion such as a cam. Since the movable portion is exposed when the sheet feed unit is in use, it is necessary to prevent the user's finger from entering the exposed portion of the movable portion. For this reason, the image forming apparatus is required to reduce the opening around the movable portion.
In general, according to one embodiment, an image forming apparatus includes an image forming unit, a sheet feed unit, a sheet tray, an elevating plate, a moving member, and a shielding member. The image forming unit forms an image on a sheet. The sheet feed unit supplies the sheet to the image forming unit. The sheet tray is provided in the sheet feed unit. The sheet is placed on the sheet tray. The elevating plate is arranged on the sheet tray. The elevating plate can be ascended and descended between the descended position where the sheet is set and the ascending position higher than the descended position. The moving member can move between a first position where the elevating plate is arranged in the descended position and a second position where the elevating plate can move to the ascending position. The shielding member is interlocked with the ascending and descending operation of the elevating plate. The shielding member shields the moving member when the elevating plate is located at the descended position.
Hereinafter, an image forming apparatus of a first embodiment will be described with reference to the drawings.
As shown in
Hereinafter, when referring to the relative position in the image forming apparatus 100, an XA direction, an XB direction, a YA direction, a YB direction, a ZA direction, and a ZB direction shown in the drawings may be used. The XA direction is a direction from left to right when standing in front of the image forming apparatus 100 (front side of the paper surface of
Hereinafter, a plane having a normal in the X direction is referred to as a YZ plane, a plane having a normal in the Y direction is referred to as a ZX plane, and a plane having a normal in the Z direction is referred to as an XY plane. The ZX plane is a plane parallel to the conveyance direction of a sheet S described later in the image forming apparatus 100. The XY plane is a horizontal plane.
The control panel 1 operates the image forming apparatus 100 by the user's operation.
The scanner unit 2 reads the image information of the object to be copied based on brightness and darkness of light. The scanner unit 2 outputs the read image information to the printer unit 3.
The printer unit 3 forms an image on the sheet S based on the image information from the scanner unit 2 or the outside.
The printer unit 3 forms an output image (toner image) with 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 onto the sheet S.
The sheet supply unit 4 supplies sheets S one by one to the printer unit 3 at the timing when the printer unit 3 forms the toner image.
The sheet supply unit 4 includes sheet feed cassettes 201, 202, and 203 and a plurality of cassette sheet feed units 21.
The sheet feed cassettes 201, 202, and 203 store sheets S of various sizes.
The plurality of cassette sheet feed units 21 are arranged above the end portions of the sheet feed cassettes 201, 202, and 203 in the XA direction, respectively. Each cassette sheet feed unit 21 includes a pickup roller 221 and a sheet feed roller 222, and a separation roller 36.
Each pickup roller 221 conveys the sheet S necessary for image formation from the sheet feed cassettes 201, 202, and 203 to the nip portion between the sheet feed roller 222 and the separation roller 36.
Each sheet feed roller 222 conveys the sheet S conveyed to the nip portion to the conveyance unit 5.
Each separation roller 36 separates one sheet S when a plurality of sheets S are conveyed.
The conveyance unit 5 includes conveyance rollers 23 and registration rollers 24. The conveyance unit 5 conveys the sheet S supplied from the sheet supply unit 4 to the registration rollers 24.
The registration rollers 24 convey the sheet S according to the timing at which the printer unit 3 transfers the toner image to the sheet S.
The conveyance rollers 23 abut the tip of the sheet S in the conveyance direction against the nip N of the registration rollers 24. The conveyance rollers 23 adjust the position of the tip of the sheet S in the conveyance direction by bending the sheet S.
The registration rollers 24 align the tip of the sheet S sent out from the conveyance rollers 23 with the nip N. Further, the registration rollers 24 convey the sheet S to a transfer unit 28 side, which will be described later.
The conveyance unit 5 includes conveyance paths 301, 302, and 303. The conveyance paths 301, 302, and 303 will be described after explaining the other configurations of the printer unit 3.
The printer unit 3 includes image forming units 251, 252, 253, and 254, an exposure unit 26, an intermediate transfer belt 27, the transfer unit 28, a fixing device 29, and a transfer belt cleaning unit 35.
The image forming units 251, 252, 253, and 254 are arranged in this order in the XA direction. Each of the image forming units 251, 252, 253, and 254 forms a toner image to be transferred to the sheet S on the intermediate transfer belt 27. The image forming units 251, 252, 253, and 254 each include a photoconductor drum 7. The image forming units 251, 252, 253, and 254 form yellow, magenta, cyan, and black toner images on the respective photoconductor drums 7.
A charger, a developing device 8, a primary transfer roller, a cleaning unit, and a static eliminator are arranged around each photoconductor drum 7. The primary transfer roller faces the photoconductor drum 7. The intermediate transfer belt 27 is sandwiched between the primary transfer roller and the photoconductor drum 7. The exposure unit 26 is arranged below the charger and the developing device 8.
Toner cartridges 331, 332, 333, and 334 are arranged above the image forming units 251, 252, 253, and 254. The toner cartridges 331, 332, 333, and 334 contain yellow, magenta, cyan, and black toners, respectively.
The toners of the toner cartridges 331, 332, 333, and 334 are supplied to the image forming units 251, 252, 253, and 254 by a toner supply pipe (not shown).
The exposure unit 26 irradiates the surface of each charged photoconductor drum 7 with a laser beam. The laser beam is controlled to emit light based on the image information. The exposure unit 26 can also adopt a configuration that emits LED light instead of laser light. In the example shown in
The intermediate transfer belt 27 is formed by an endless belt. Tension is applied to the intermediate transfer belt 27 by a plurality of rollers that are in contact with the inner peripheral surface. The intermediate transfer belt 27 is stretched flat along the X direction. The inner peripheral surface of the intermediate transfer belt 27 abuts on a support roller 281 at the most distant position in the XA direction in the tensioning direction. The inner peripheral surface of the intermediate transfer belt 27 abuts on a transfer belt roller 32 at the most distant position in the XB direction in the tensioning direction.
The support roller 281 constitutes a part of the transfer unit 28 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 the cleaning position.
The image forming units 251, 252, 253, and 254 excluding the primary transfer roller are arranged in this order in the XA direction on the depicted lower surface side of the intermediate transfer belt 27. The image forming units 251, 252, 253, and 254 are arranged at intervals from each other in the region between the transfer belt roller 32 and the support roller 281.
A transfer bias is applied to the respective primary transfer rollers of the image forming units 251, 252, 253, and 254 when the toner image reaches the primary transfer position. Each primary transfer roller transfers (primary transfer) the toner image on the surface of each photoconductor drum 7 onto the intermediate transfer belt 27.
In the intermediate transfer belt 27, the transfer unit 28 is arranged at a position adjacent to the image forming unit 254.
The transfer unit 28 includes the support roller 281 and a secondary transfer roller 282. The secondary transfer roller 282 and the support roller 281 sandwich the intermediate transfer belt 27. The position where the secondary transfer roller 282 and the 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 to the sheet S by the transfer bias.
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 heat and pressure. The fixing device 29 is arranged above the transfer unit 28.
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 the toner on the surface of the intermediate transfer belt 27.
The conveyance paths 301 and 302 that convey the sheet S from the bottom to upward are formed in this order between the registration rollers 24 and the transfer unit 28 and between the transfer unit 28 and the fixing device 29, respectively.
Each of the conveyance paths 301, 302, and 303 includes a conveyance guide unit that faces each other with the sheet S sandwiched therebetween, and a conveyance roller that is provided as needed.
The manual feed unit 10 supplies the sheet S on which the image is formed to the printer unit 3. The manual feed unit 10 includes a manual sheet feed unit 11, a manual feed tray 13 (sheet tray), and an elevating mechanism 40.
The manual feed tray 13 can rotate about an axis extending in the Y direction. When the manual feed tray 13 is used, the manual feed tray 13 is opened by being rotated clockwise as shown by a solid line. Sheets S of various sizes can be placed on the opened manual feed tray 13.
When the manual feed tray 13 is not used, the manual feed tray 13 is rotated counterclockwise as shown by the two-dot chain line and is housed in the side portion of the printer unit 3 in the XA direction.
The manual sheet feed unit 11 separately feeds the sheet S placed on the manual feed tray 13 and conveys the sheet toward the registration rollers 24. The manual sheet feed unit 11 includes a pickup roller 121, a sheet feed roller 122, and the separation roller 36.
The pickup roller 121 and the sheet feed roller 122 in the manual sheet feed unit 11 have the same configurations as the pickup roller 221 and the sheet feed roller 222 in the cassette sheet feed unit 21.
The separation roller 36 in the manual sheet feed unit 11 has the same configuration as the separation roller 36 in the cassette sheet feed unit 21 except that the separation roller 36 comes into contact with the sheet feed roller 122.
Next, the detailed configuration of the manual feed tray 13 will be described.
As shown in
A sheet feed opening 182 through which the sheet S can pass is formed in the lower portion of the tray storage unit 181. The pickup roller 121 projects in the XA direction at the center of the upper portion of the sheet feed opening 182 in the Y direction.
At the lower end portion of the tray storage unit 181, a rotary support shaft 37 projects from each inner surface of the tray storage unit 181 in the Y direction from the apparatus main body covered with the side cover 18. However,
Each rotary support shaft 37 extends coaxially with an axis extending in the Y direction. Each rotary support shaft 37 is fitted to a bearing portion 130 (see
Each inner wall of the side cover 18 in the Y direction is provided with a guide groove 183 extending in the Z direction. However,
Each link 17 holds the manual feed tray 13 at a predetermined angle with respect to the horizontal plane (XY plane) in a state where the manual feed tray 13 is opened outward from the tray storage unit 181. Each link 17 connects each side surface of the manual feed tray 13 in the Y direction with each guide groove 183. Each link 17 includes a connecting hole 171 and a connecting pin 172 at both ends in the longitudinal direction.
The connecting hole 171 connects a mounting protrusion 135, which will be described later, of the manual feed tray 13.
The connecting pin 172 is movably connected to each guide groove 183 in the Z direction.
With such a configuration, the manual feed tray 13 can rotate between the closed state and the open state. The closed state is a state in which the manual feed tray 13 is stored inside the tray storage unit 181 in a posture along the vertical plane. The open state is a state in which the manual feed tray 13 is opened toward the outside of the tray storage unit 181 in the XA direction at an angle defined by the link 17 with respect to the horizontal plane.
Hereinafter, unless otherwise specified, the manual feed tray 13 in the open state will be described.
As shown in
The bottom plate 131 forms the lower surface in the open state. The bottom plate 131 is substantially flush with the side cover 18 outside the tray storage unit 181 in the closed state. In the closed state, the bottom plate 131, together with the side cover 18, forms a part of the right side surface of the image forming apparatus 100.
The front side plate 132 projects upward from the end portion of the bottom plate 131 in the YA direction. The front side plate 132 includes the bearing portion 130, a mounting protrusion 135, and a rotary support shaft 136.
The bearing portion 130 supports the rotary support shaft 37 (see
The mounting protrusion 135 is engaged with the connecting hole 171 (see
The rotary support shaft 136 rotatably supports the elevating plate 14, which will be described later, around a central axis C of the rotary support shaft 136. The rotary support shaft 136 projects from the front side plate 132 in the YB direction.
The rear side plate 133 projects upward from the end portion of the bottom plate 131 in the YB direction. The rear side plate 133 has a shape plane-symmetrical with the front side plate 132, with the ZX plane including the central axis in the Y direction of the bottom plate 131 as a symmetrical plane. Therefore, although not visible in
The upper plate 134 covers the bottom plate 131 located in the XA direction from each rotary support shaft 136 from above. The upper plate 134 is arranged at the same height as the upper ends of the front side plate 132 and the rear side plate 133.
The elevating plate 14 and the upper plate 134 form a mounting surface on which the sheet S (not shown) is mounted. The elevating plate 14 is arranged inside the front side plate 132 and the rear side plate 133 in the Y direction from the tip of the upper plate 134 in the XB direction to the tip of the bottom plate 131 in the XB direction. The outer shape of the elevating plate 14 seen from above is substantially rectangular.
A flat tip mounting surface 141 long in the Y direction is formed at the tip portion of the elevating plate 14 in the XB direction. A friction pad 142 that increases the frictional force with the sheet S is arranged at the center of the tip mounting surface 141 in the longitudinal direction. The friction pad 142 is provided at a position capable of coming into contact with the pickup roller 121. The friction pad 142 suppresses double feeding of the lowest sheet S placed on the manual feed tray 13.
The end portion of the elevating plate 14 in the XA direction is rotatably supported by each rotary support shaft 136. In the elevating plate 14, the biasing member 16 is arranged between the back side of the tip mounting surface 141 and the bottom plate 131.
The configuration of the biasing member 16 pushes up the elevating plate 14 in the direction in which the elevating plate 14 is separated from the bottom plate 131. Examples of the biasing member 16 include a spring and an elastic member.
In this embodiment, a compression coil spring is provided as the biasing member 16. The biasing member 16 is arranged near both ends in the Y direction below the tip mounting surface 141. The biasing force of the biasing member 16 has a magnitude such that when the loadable sheet S is set on the elevating plate 14, the uppermost sheet S comes into contact with the pickup roller 121 and a frictional force capable of feeding the uppermost sheet S between the uppermost sheet S and the pickup roller 121 is generated.
A pair of guide fences 15 are provided in the region of the elevating plate 14 adjacent to the tip mounting surface 141 in the XA direction. The pair of guide fences 15 align the direction of the sheet S in the X direction with both end portions of the sheet S placed on the elevating plate 14 in the Y direction sandwiched therebetween.
Each of the pair of guide fences 15 includes a protrusion extending in the X direction above the elevating plate 14. The height of each guide fence 15 is higher than the total thickness of the number of sheets S that can be loaded on the manual feed tray 13. Each guide fence 15 is supported by the elevating plate 14 so as to be movable in the Y direction. The distance between the protrusions of each guide fence 15 in the Y direction can be changed by the user.
In the elevating plate 14, cam contact surfaces 143 are formed at both end portions in the Y direction at the tip portion in the XB direction. A cam plate portion 411 (see
In the present embodiment, a plate-shaped protrusion 144 is provided between each cam contact surface 143 and the tip mounting surface 141, respectively. Each plate-shaped protrusion 144 has a plate shape parallel to the front side plate 132 and the rear side plate 133. Each plate-shaped protrusion 144 projects in a chevron shape above the elevating plate 14. In the X direction, each plate-shaped protrusion 144 extends from the tip portion of the elevating plate 14 in the XB direction to the range extending to the tip portion of the guide fence 15 in the XB direction.
With such a configuration, in the manual feed tray 13 alone, the tip portion of the elevating plate 14 biased by the biasing member 16 in the XB direction projects upward from the upper ends of the front side plate 132 and the rear side plate 133. When an external force toward the bottom plate 131 acts on each cam contact surface 143, the elevating plate 14 descends toward the bottom plate 131. At the lowest position of the elevating plate 14, the upper surface of the elevating plate 14 is flush with the upper plate 134.
The arrangement of the elevating plate 14 lowered to the lowest position is hereinafter referred to as a descended position.
The arrangement in which the XB direction end portion of the elevating plate 14 is higher than the descended position with respect to the bottom plate 131 is referred to as an ascending position. In the manual feed tray 13 alone shown in
In the manual feed tray 13 in the open state, the elevating plate 14 is usually arranged at the descended position by the elevating mechanism 40 (see
As shown in
As shown in
The pressing member 41 comes into contact with each cam contact surface 143 (see
The front pressing member 41 and the rear pressing member 41 have shapes that are plane-symmetric with respect to the ZX plane at the center of their respective arrangement positions. Therefore, in the following, an example of the rear pressing member 41 will be described. Regarding the shape of the front pressing member 41, the YB direction may be read as the YA direction in the following description of the rear pressing member 41.
As shown in
The gear portion 412 receives a driving force from the drive transmission unit 45 described later. For example, the gear portion 412 is a spur gear. A bearing portion 413 penetrates the central portion of the gear portion 412 in the Y direction.
A rotary support shaft 44 shown in
As shown in
The cam plate portion 411 extends outward in the radial direction from the central portion of the gear portion 412, and the tip thereof projects outward in the radial direction. The cam plate portion 411 is formed in a fan-shaped range including the bearing portion 413 inside the gear portion 412 in the radial direction. The bearing portion 413 penetrates the cam plate portion 411 in the plate thickness direction.
The end surface of the radially outwardly protruding portion of the gear portion 412 in the cam plate portion 411 is the cam surface 416. The shape of the cam surface 416 seen from the YB direction is a curved surface represented by a curve ra, rb, rc, rd, re, rf, rg, rh, ri (hereinafter referred to as a curve [ra-ri]). The points ra, rb, . . . , ri on the curve [ra-ri] are arranged in this order counterclockwise with respect to the central axis O when viewed from the YB direction. The curve [ra-ri] is not particularly limited to a line-symmetrical shape. However, in the present embodiment, the curve [ra-ri] is line-symmetric with respect to the straight line passing through the central axis O and the point re (the bisector of the cam).
The distance (radius) from the central axis O to the cam surface 416 on a plane orthogonal to the central axis O and passing through the cam surface 416 is referred to as a cam radius CR. In the following, an example of the shape of the curve [ra-ri] will be described based on the change in the cam radius CR when advancing counterclockwise at an equal angle when viewed from the YB direction (hereinafter, simply referred to as “to advance”).
The cam radius CR is substantially equal to the outer radius of the gear portion 412 at the point ra and the point ri. The cam radius CR increases steeply as advancing from the point ra to the point rb. The increase rate of the cam radius CR gradually decreases as advancing from the point rb to the point rc. The increase rate of the cam radius CR gradually decreases as advancing from the point rc to the point rd. The cam radius CR is constant as advancing from the point rd to the point rf. In this case, the curve rd, re, rf is an arc centered on the central axis O. The central angle (∠rdOrf) of this arc is about 55 degrees. The change of the cam surface 416 from the point rf to the point ri is the same as the change when advancing clockwise from the point ri to the point rf at an equal angle.
However, the cam radius CR may gradually increase as advances from the point rd to the point re and may gradually decrease as advancing from the point re to the point rf. Here, the point re is a point that bisects the cam surface 416 between the point rd and the point rf.
In the present embodiment, the cam surface 416 is smoothly curved and continuous at the points ra, . . . , ri.
Due to the shape of the cam surface 416, the outer shape of the cam plate portion 411 when viewed from the YB direction is a fan shape that bulges outward in the radial direction from the gear portion 412 as a whole. However, rounded corners are formed at both end portions (points rb to rd and points rf to rh) of the cam plate portion 411 protruding from the gear portion 412 in the circumferential direction.
The cam radius CR is the maximum at least at the point re.
As shown in
The drive motor 46 and the drive transmission unit 45 are used to swing the pressing member 41. The drive motor 46 is communicably connected to the control unit 6.
The type of the drive motor 46 is not particularly limited as long as each pressing member 41 can swing in cooperation with the drive transmission unit 45. For example, the drive transmission unit 45 may or may not include a swing mechanism that converts the rotation of the motor shaft 461 into a swing motion. The swing mechanism can be formed, for example, by a cam, a link, or a combination thereof.
Below, as shown in
However, when the drive transmission unit 45 includes a swing mechanism, the rotation direction of the drive motor 46 may be one direction.
The drive transmission unit 45 transmits the rotation of the motor shaft 461 to the pressing member 41. The configuration of the drive transmission unit 45 is not particularly limited as long as the rotation can be transmitted. In the example shown in
The drive transmission unit 45 includes a first gear 451, a second gear 452, a rotary shaft 43, a third gear 453, and a fourth gear 454.
The first gear 451 is a worm gear fixed to the motor shaft 461.
The second gear 452 is a worm wheel that meshes with the first gear 451. The second gear 452 is rotatable about an axis extending in the Y direction.
The rotary shaft 43 extends in the Y direction. The rotary shaft 43 is a rotary shaft that transmits the rotation of the second gear 452. The rotary shaft 43 has a length that penetrates the front side plate (not shown, the same applies hereinafter) and the rear side plate (not shown, the same applies hereinafter) facing in the Y direction. The rotary shaft 43 is rotatably supported by bearings 455 arranged on the front side plate and the rear side plate of the apparatus main body of the printer unit 3, respectively.
The third gear 453 and the fourth gear 454 transmit the rotation of the rotary shaft 43 to the front pressing member 41 and the rear pressing member 41. Therefore, as the third gears 453 and the fourth gears 454, a third gear 453 and a fourth gear 454 on the rear side (YB direction side) of the front side plate and a third gear 453 and a fourth gear 454 on the front side (YA direction side) of the rear side plate are arranged.
The number of teeth and modules of each third gear 453 are equal to each other. The number of teeth and modules of each fourth gear 454 are equal to each other. Hereinafter, when it is necessary to distinguish each third gear 453, the third gear 453 on the rear side (YB direction side) of the front side plate is referred to as the front third gear 453, and the third gear 453 on the front side (YA direction side) of the rear side plate is referred to as the rear third gear 453. When it is necessary to distinguish each fourth gear 454, the fourth gear 454 on the rear side (YB direction side) of the front side plate is referred to as the front fourth gear 454 and the fourth gear 454 on the front side (YA direction side) of the rear side plate is referred to as the rear fourth gear 454.
The rear third gear 453 is fixed to the front side of the rear side plate at the rear end portion of the rotary shaft 43. The front third gear 453 is fixed to the rear side of the front side plate at the front end portion of the rotary shaft 43. Therefore, the rear third gear 453 and the front third gear 453 rotate in the same direction as the rotary shaft 43.
The rear fourth gear 454 is an idler gear provided in the transmission path between the rear third gear 453 and the gear portion 412 of the rear pressing member 41. The rear fourth gear 454 is rotatably attached to a rotary support shaft 456 protruding from the rear side plate in the YA direction.
The front fourth gear 454 is an idler gear provided in the transmission path between the front third gear 453 and the gear portion 412 of the front pressing member 41. The front fourth gear 454 is rotatably attached to the rotary support shaft 456 protruding from the front side plate in the YB direction.
According to the drive transmission unit 45 having such a configuration, when the drive motor 46 rotates, the pressing members 41 rotate in synchronization with each other in the same direction. Therefore, the pressing member 41 swings around the central axis O in response to the forward and reverse rotation of the drive motor 46. That is, the central axis O is a swing axis that extends in the Y direction in the horizontal direction and swings the cam plate portion 411 of the pressing member 41.
The elevating mechanism 40 includes a position detection sensor 60 that detects the swing position of the pressing member 41. For example, the position detection sensor 60 detects the most clockwise swing position and the most counterclockwise swing position of the pressing member 41 when viewed from the YB direction and sends the detected signal to the control unit 6 described later.
The most clockwise swing position is the position where the cam plate portion 411 faces downward and the elevating plate 14 is pushed down to the descended position (see
The most counterclockwise swing position is the position where the cam plate portion 411 faces upward and is separated from the most raised elevating plate 14 (see
As shown in
For example, the control unit 6 sends a control signal to the drive motor 46 (see
As the device configuration of the control unit 6, for example, a processor such as a central processing unit (CPU) may be used.
Next, the operation of the image forming apparatus 100 will be described focusing on the ascending and descending operation of the elevating plate 14 and the swinging operation of the pressing member 41 in the manual feed tray 13.
First, the image forming operation of the image forming apparatus 100 will be briefly described.
In the image forming apparatus 100 shown in
When an operation input for image formation is made from the control panel 1, the control unit 6 controls to start sheet feeding and image formation from the sheet supply unit 4.
The image forming units 251, 252, 253, and 254 form an electrostatic latent image on each photoconductor drum 7 based on the image information corresponding to each color. Each electrostatic latent image is developed by the developing device 8. Therefore, a toner image corresponding to the electrostatic latent image is formed on the surface of each photoconductor drum 7.
Each toner image is primarily transferred to the intermediate transfer belt 27 by each transfer roller. As the intermediate transfer belt 27 moves, the toner images are sequentially superposed without causing color shift and sent to the transfer unit 28.
The sheet S is fed from the registration rollers 24 to the transfer unit 28. The toner image that reached the transfer unit 28 is secondarily transferred to the sheet S. The secondary transferred toner image is fixed to the sheet S by the fixing device 29. As a result, an image is formed on the sheet S.
Next, the operation of the manual feed tray 13 will be described in detail.
In order to place the sheet S on the manual feed tray 13, as shown in
As shown in
In such a descended position of the elevating plate 14, the cam surface 416 at the first position has a substantially central portion in the circumferential direction in contact with each cam contact surface 143.
In the drawing shown in
On the other hand, in order to raise the elevating plate 14 to a position where a sheet can be fed, as shown in
The elevating plate 14 is raised to a position where the sheet S (not shown) can come into contact with the pickup roller 121 (see
The elevating plate 14 shown in
Here, the appearance of the side cover 18 at the descended position of the elevating plate 14 will be described.
As shown in
Next, the appearance of the side cover 18 will be described with reference to the vicinity of the end portion of the sheet feed opening 182 in the YB direction.
As shown in
The inner cover portion 185 is a plate-shaped portion that covers the periphery of the rotary support shaft 44 and extends along the ZX plane. The inner cover portion 185 covers a part of the rear pressing member 41 at the cam-up position from the YA direction side. Specifically, the inner cover portion 185 covers the cam plate portion 411 at the cam-up position as a whole from the YA direction side. A gap that opens in the Y direction is formed below the inner cover portion 185. A part of the gear portion 412 at the cam-up position is exposed from the gap. This gap is large enough that a user's finger cannot enter, for example. For example, the size of the gap is about 2 mm or less.
As shown in
The above-mentioned inner cover portion 185 is similarly provided at the end portion of the side cover portion 184 in the YA direction. The inner cover portion 185 in the YA direction similarly covers the front pressing member 41 (see
Next, the shutter will be described.
The shutters 50 are arranged adjacent to each other on the outside (front side and rear side) of the elevating plate 14 in the Y direction. The shutter 50 is arranged between the plate-shaped protrusion 144 of the elevating plate 14 and the pressing member 41 in the Y direction.
The front shutter 50 and the rear shutter 50 have shapes that are plane-symmetric with respect to the ZX plane at the center of their respective arrangement positions. Therefore, in the following, an example of the rear shutter 50 will be described. As for the shape of the front shutter 50, the YB direction of the following description regarding the rear shutter 50 may be read as the YA direction.
As shown in
The rear shutter 50 is rotatably provided about an axis P extending in the Y direction in the horizontal direction. The axis P is a swing axis that swings between a position where the rear shutter 50 shields a part of the rear pressing member 41 (see
The rear shutter 50 and the manual feed tray 13 include rotary support members 71 and 72 that are rotatably supported by each other. In the example shown in
However, such a mode of the rotation support member is an example. For example, the rotation support member is not limited to the above example and may be a protrusion provided on the rear side plate 133 of the manual feed tray 13 and a through hole provided on the rear shutter 50. The protrusion is not limited to a columnar convex portion and may have a pair of arc-shaped portions along the inner diameter of the through hole 72. Further, the portion into which the protrusion is inserted is not limited to the through hole and may be a recess. The mode of the rotation support member can be changed according to the required specifications.
The arm portion 52 is formed in a plate shape along the ZX plane. In the state of
The shielding portion 51 is formed in a plate shape along the ZX plane at a position offset in the Y direction with respect to the arm portion 52. The shielding portion 51 extends bifurcated from a portion (step portion 53) opposite to the portion overlapping the axis P in the direction in which the arm portion 52 extends. In the state of
The elevating plate 14 and the rear shutter 50 include engaging members 81 and 82 that engage with each other in the ascending and descending operation of the elevating plate 14. In the example of
The protrusion 81 projects in the YB direction from the surface of the plate-shaped protrusion 144 of the elevating plate 14 on the YB direction side. The protrusion 81 is formed in a columnar shape extending in the Y direction.
The rail 82 includes two walls 83 and 84 sandwiching the protrusion 81. The two walls 83 and 84 are arranged at intervals substantially the same as the outer diameter of the protrusion 81, respectively. The two walls 83 and 84 extend linearly in parallel with each other when viewed from the Y direction. In the state where the protrusion 81 is arranged in the rail 82, the protrusion 81 can move along the rail 82.
The rail 82 includes two contact portions 85 and 86 to which the protrusion 81 can come into contact. The two contact portions 85 and 86 are a first contact portion 85 provided on the open end side of the rail 82 and a second contact portion 86 provided on the rail 82 near the arm portion 52 (step portion 53).
The first contact portion 85 is a portion where the protrusion 81 abuts at the ascending position (see
The second contact portion 86 is a portion where the protrusion 81 abuts at the descended position (see
For example, when the elevating plate 14 moves from the ascending position to the descended position (when moving from the position shown in
On the other hand, when the elevating plate 14 moves from the descended position to the ascending position (when moving from the position shown in
Next, the operations of the pressing member 41 and the shutter 50 will be described with an example of the rear pressing member 41 and the rear shutter 50. The operations of the front pressing member 41 and the front shutter 50 are the same as those of the rear pressing member 41 and the rear shutter 50, although not particularly illustrated.
As shown in
Although not shown, when the elevating plate 14 is located in the descended position, the cam plate portion 411 of the rear pressing member 41 faces downward in the cam-down position, and thus, most of the opening 19 is closed by the cam plate portion 411. On the other hand, when the elevating plate 14 is located in the descended position, the cam plate portion 411 of the rear pressing member 41 faces upward at the cam-up position (the gear portion 412 of the rear pressing member 41 faces downward), and thus, the opening 19 is closed by the gear portion 412. However, when the elevating plate 14 is located in the descended position, the opening 19 cannot be completely closed by the rear pressing member 41 at the cam-up position and a gap is partially formed (see
In this embodiment, as shown in
The arrangement of the shielding portion 51 arranged in this way is referred to as a shielding position because the shielding portion 51 overlaps with the region in the height direction occupied by the gear portion 412 of the rear pressing member 41 at the second position when viewed from the YB direction.
As shown in
In the present embodiment, the swing direction in which the cam plate portion 411 moves from the first position to the second position (the direction in which the cam plate portion 411 swings from the position shown in
Such a descended position of the elevating plate 14 is automatically formed by the control of the control unit 6 when the manual feed tray 13 is opened. That is, when the control unit 6 detects that the manual feed tray 13 is opened, the control unit 6 refers to the detection signal of the position detection sensor 60 (see
When the elevating plate 14 moves to the descended position, the user can place the sheet S on the upper surface of the manual feed tray 13.
When the image formation start signal is generated by the operation of the control panel 1 or an external signal, the control unit 6 sends a control signal for rotating the pressing member 41 upward to the drive motor 46.
For example, as shown in
For example, in the example shown in
For example, when the rear pressing member 41 reaches the most counterclockwise swing position, the position detection sensor 60 (see
As shown in
Meanwhile, the user can push down the elevating plate 14 with the user's finger from the state of
As shown in
As shown in
In this way, when the elevating plate 14 moves to the ascending position, the sheet S is fed and image formation is performed. When the sheet feeding required for image formation is completed, the control unit 6 moves the elevating plate 14 to the descended position.
The movement of the elevating plate 14 from the ascending position to the descended position is performed in the reverse order of the above by the control unit 6 reversing the drive motor 46.
When the rear pressing member 41 rotates clockwise and the elevating plate 14 moves to the descended position, as shown in
As described above, the image forming apparatus 100 of the present embodiment includes the image forming units 251 to 254, the sheet feed unit 10, the sheet tray 13, the elevating plate 14, the pressing member 41, and the shutter 50. The image forming units 251 to 254 form an image on the sheet S. The sheet feed unit 10 supplies the sheet S to the image forming units 251 to 254. The sheet tray 13 is provided in the sheet feed unit 10. The sheet S is placed on the sheet tray 13. The elevating plate 14 is arranged on the sheet tray 13. The elevating plate 14 can be ascended and descended between the descended position in which the sheet S is set and the ascending position higher than the descended position. The pressing member 41 is movable between the first position in which the elevating plate 14 is arranged in the descended position and the second position in which the elevating plate 14 can be moved to the ascending position. The shutter 50 is interlocked with the ascending and descending operation of the elevating plate 14. The shutter 50 shields the pressing member 41 when the elevating plate 14 is in the descended position.
According to the image forming apparatus 100 of the present embodiment, the shutter 50 shields the pressing member 41 at the descended position of the elevating plate 14. Therefore, it is possible to provide the image forming apparatus 100 capable of reducing the opening 19 around the pressing member 41.
In the meantime, the user can push down the elevating plate 14 with the user's finger from the state of
In particular, in the present embodiment, since the shutter 50 rotates in conjunction with the ascending and descending operation of the elevating plate 14, it is not necessary to provide a dedicated drive mechanism for rotating the shutter 50. Therefore, the opening 19 around the pressing member 41 can be reduced with a simple structure.
The elevating plate 14 has the following effects by shielding the pressing member 41 when the elevating plate 14 is located in the ascending position.
Since the elevating plate 14 shields the pressing member 41 at the ascending position of the elevating plate 14, the opening 19 around the pressing member 41 can be reduced. As a result, the shutter 50 shields the pressing member 41 at the descended position of the elevating plate 14 and the elevating plate 14 itself shields the pressing member 41 at the ascending position of the elevating plate 14, and thus, when the elevating plate 14 is raised and lowered (that is, when the elevating plate 14 is raised and when the elevating plate 14 is lowered, respectively), the opening 19 around the pressing member 41 can be reduced.
The shutter 50 has the following effects by not shielding the pressing member 41 when the elevating plate 14 is in the ascending position.
Since the shutter 50 is retracted from the opening 19 around the pressing member 41 at the ascending position of the elevating plate 14, for example, the elevating plate 14 or the like can advance into the opening 19 around the pressing member 41.
The shutter 50 is provided so as to be rotatable around the axis P extending horizontally and thus has the following effects.
In order to rotate the shutter 50 in conjunction with the ascending and descending operation of the elevating plate 14, it is not necessary to provide a dedicated rotation switching mechanism for switching the rotation direction of the shutter 50. Therefore, with a simple configuration, the shutter 50 can be rotated in conjunction with the ascending and descending operation of the elevating plate 14.
The elevating plate 14 and the shutter 50 have the following effects by including engaging members 81 and 82 that engage with each other in the ascending and descending operation of the elevating plate 14.
As compared with the case where the engaging members 81 and 82 are provided separately from the elevating plate 14 and the shutter 50, the shutter 50 can be rotated in conjunction with the ascending and descending operation of the elevating plate 14 with a simple structure.
The engaging members 81 and 82 have the following effects by including the protrusion 81 provided on the elevating plate 14 and the rail 82 provided on the shutter 50 and including two walls 83 and 84 sandwiching the protrusion 81.
When the protrusion 81 moves in the rail 82 in the ascending and descending operation of the elevating plate 14, the shutter 50 moves according to the ascending and descending operation of the elevating plate 14. Therefore, the shutter 50 can be interlocked with the ascending and descending operation of the elevating plate 14 with a simple configuration.
The protrusion 81 is formed in a columnar shape. The two walls 83 and 84 extend parallel to each other. With the above configuration, the following effects are obtained.
Since the protrusion 81 moves smoothly in the rail 82 in the ascending and descending operation of the elevating plate 14, the shutter 50 can be smoothly interlocked with the ascending and descending operation of the elevating plate 14.
Since the sheet tray 13 is a manual feed tray, the following effects are obtained.
It is possible to provide the image forming apparatus 100 capable of reducing the opening 19 around the pressing member 41 when the elevating plate 14 is raised and lowered in manual sheet feeding.
Next, a second embodiment will be described with reference to
As shown in
As shown in
According to the second embodiment, the following effects are obtained by connecting the portions on the side of the pressing member 41 to each other in the two walls 83 and 84.
In the descended position of the elevating plate 14, as compared with the case where the portions on the side of the pressing member 41 are separated from each other in the two walls 83 and 84 (see
The shutter 2050 has the following effects by entirely shielding the pressing member 41 when the elevating plate 14 is in the descended position.
Since the shutter 2050 entirely shields the pressing member 41 at the descended position of the elevating plate 14, the opening 19 around the pressing member 41 can be reduced as much as possible.
Next, a modification of the embodiment will be described.
The elevating plate is not limited to shielding the pressing member when the elevating plate is located in the ascending position. For example, the elevating plate may not shield the pressing member when the elevating plate is located in the ascending position. For example, the mode of the arrangement of the elevating plate with respect to the pressing member can be changed according to the required specifications.
The shutter is not limited to not shielding the pressing member when the elevating plate is in the ascending position. For example, the shutter may shield the pressing member when the elevating plate is in the ascending position. For example, the mode of arrangement of the shutter with respect to the pressing member can be changed according to the required specifications.
The shutter is not limited to being provided so as to be rotatable around an axis extending horizontally. For example, the shutter may be rotatably provided about an axis extending in a direction intersecting the horizontal direction. For example, the mode of the rotation axis (swing axis) of the shutter can be changed according to the required specifications.
The elevating plate and the shutter are not limited to including engaging members that engage with each other in the ascending and descending operation of the elevating plate. For example, the engaging member may be provided separately from the elevating plate and the shutter. For example, the mode of the engaging member can be changed according to the required specifications.
The engaging member is not limited to including a protrusion provided on the elevating plate and a rail provided on the shutter and including two walls sandwiching the protrusion. For example, the engaging member may be a protrusion provided on the shutter and a rail provided on the elevating plate. For example, the mode of the arrangement of the protrusion and the rail can be changed according to the required specifications.
The protrusion is not limited to being formed in a columnar shape. For example, the protrusion may have a pair of arcuate portions. Also, the two walls are not limited to extending parallel to each other. For example, the two walls may extend in a direction intersecting each other. Further, the portion (inside the rail) into which the protrusion is inserted is not limited to the through hole but may be a recess. The mode of the engaging member can be changed according to the required specifications.
The sheet tray is not limited to the manual feed tray. For example, the sheet tray may be a tray other than the manual feed tray. For example, the mode of the sheet tray can be changed according to the required specifications.
According to at least one embodiment described above, the image forming apparatus 100 includes the image forming units 251 to 254, the sheet feed unit 10, the sheet tray 13, the elevating plate 14, the pressing member 41, and the shutter 50. The image forming units 251 to 254 form an image on the sheet S. The sheet feed unit 10 supplies the sheet S to the image forming units 251 to 254. The sheet tray 13 is provided in the sheet feed unit 10. The sheet S is arranged on the sheet tray 13. The elevating plate 14 is arranged on the sheet tray 13. The elevating plate 14 can be ascended and lowered between the descended position in which the sheet S is set and the ascending position higher than the descended position. The pressing member 41 is movable between the first position in which the elevating plate 14 is arranged in the descended position and the second position in which the elevating plate 14 can be moved to the ascending position. The shutter 50 is interlocked with the ascending and descending operation of the elevating plate 14. The shutter 50 shields the pressing member 41 when the elevating plate 14 is in the descended position.
According to the image forming apparatus 100 of the embodiment, the shutter 50 shields the pressing member 41 at the descended position of the elevating plate 14. Therefore, it is possible to provide the image forming apparatus 100 capable of reducing the opening 19 around the pressing member 41.
While certain embodiments have been described these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms: furthermore various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.