JP2008265914A - Paper feeder and image forming device provided with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of attaining miniaturization by space-saving, reduction of the number of parts and reduction of cost by simplifying a drive system. <P>SOLUTION: In the paper feeder for feeding the paper by a cassette paper feed roller 13a or a manual paper feed roller 5 rotated/driven by a motor (drive source) 33, a clutch 31 and an idle gear 32 are provided on a cassette paper feed roller shaft for rotating/driving the cassette paper feed roller 13a, the drive force from the motor 33 is selectively transmitted to the cassette paper feed roller 13a through the clutch 31, and it is transmitted to the manual paper feed roller 5 through the idle gear 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet feeding device for feeding a sheet as a recording material to an image forming unit, and an image forming apparatus including the sheet feeding device.

  In an image forming apparatus such as a copying machine or a printer that employs an electrophotographic system, a sheet is fed to an image forming unit, and a toner image formed on an image carrier in the image forming unit is transferred onto the sheet. An image is formed through a process of fixing the toner image onto a sheet. As a method of feeding a sheet to an image forming unit, a plurality of sheets are stacked and accommodated in a sheet cassette in advance. From the cassette feeding to pick up the paper one by one and feed it to the image forming unit, and the manual feeding to feed the paper set one by one on the manual tray to the image forming unit You can choose.

Conventionally, the cassette feeding roller used for cassette feeding and the manual feeding roller used for manual feeding have a configuration in which driving force from a driving source such as a motor is transmitted by independent driving systems. It was adopted.
Japanese Unexamined Patent Publication No. 7-117787 JP 2000-281226 A JP 2005-126173 A

  However, in the conventional configuration in which the driving force from the driving source is transmitted to the cassette paper feeding roller and the manual paper feeding roller by the independent driving systems to rotate them, the space for installing the driving system becomes large, and the paper feeding device In addition, the image forming apparatus is increased in size, and the number of parts such as gears constituting the drive system is increased, resulting in an increase in cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet feeding device capable of simplifying the drive system to reduce the size, reduce the number of parts, and reduce the cost by saving space. Another object of the present invention is to provide an image forming apparatus.

  In order to achieve the above object, according to a first aspect of the present invention, in the paper feeding device for feeding paper by a cassette paper feeding roller or a manual paper feeding roller that is rotationally driven by a driving source, the cassette paper feeding roller is rotationally driven. A clutch and an idle gear are provided on the cassette paper feed roller shaft to selectively transmit the driving force from the drive source to the cassette paper feed roller via the clutch and the manual feed via the idle gear. It is configured to transmit to a paper roller.

  According to a second aspect of the present invention, in the first aspect of the present invention, a missing gear that selectively meshes with a drive gear that rotationally drives the manual paper feed roller, and biases the missing gear in one rotation direction. An urging means, an input gear that selectively engages with the toothless gear and returns the toothless gear to the initial position against the urging force of the urging means, and holds / holds the toothless gear at the initial position. Contact / separation means for releasing is provided, and the input gear meshes with the idle gear.

  According to a third aspect of the present invention, the paper is fed to the image forming unit by the paper feeding means, and after the toner image formed on the image carrier in the image forming unit is transferred onto the paper, the toner image is applied to the paper. In the image forming apparatus to be fixed, the sheet feeding unit is constituted by the sheet feeding apparatus according to claim 1.

  According to the present invention, the driving force transmitted from the driving source to the cassette sheet feeding roller shaft is selectively transmitted to the cassette sheet feeding roller via the clutch, and is also transmitted to the manual sheet feeding roller via the idle gear. Since the drive power transmission system to the cassette paper feed roller and the manual paper feed roller is one system, the drive system is simplified and space saving is achieved, the number of parts is reduced, and the size and cost are reduced. Figured.

  Further, according to the present invention, since the idle gear is arranged on the cassette paper feed roller shaft, the driving force can be transmitted from the idler gear to the manual paper feed roller without being affected by ON / OFF of the clutch.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[Image forming apparatus]
FIG. 1 is a side sectional view of a laser beam printer as an embodiment of an image forming apparatus according to the present invention.

  In the illustrated laser beam printer 1, an inclined concave discharge tray 3 is provided at the center of the upper surface of a box-shaped main body (housing) 2. An openable and closable manual feed tray 4 is provided at the upper part of the front surface of the main body 2 (the right side in FIG. 1 is the front), and the manual feed paper that is rotatably provided in the manual feed tray 4 and the main body 2 at the back thereof. The roller 5 constitutes a manual sheet feeding unit 6. The details of the manual sheet feeder 6 will be described later.

  Thus, the laser beam printer 1 conveys an image on a sheet based on image data transmitted from a terminal (not shown) while conveying a sheet as a recording material along a conveyance path L provided in the main body 2. The conveyance path L is substantially L-shaped in a side view and extends to the paper discharge tray 3.

  The laser beam printer 1 includes a cassette paper feeding unit 7 provided at a lower portion of the main body 2, an image forming unit 8 provided at a substantially central portion in the main body 2 above the cassette paper feeding unit 7, A fixing unit 9 disposed behind the image forming unit 8 and a concave paper discharge unit 10 provided on the upper surface of the main body 2 above the fixing unit 9 are provided.

  The cassette sheet feeding unit 7 stacks and stores a plurality of sheets in a rectangular box-shaped sheet feeding cassette 11 having an open top surface, and picks a roller 12 that takes out the sheets in the sheet feeding cassette 11 one by one. A cassette paper feed roller 13a and a separation roller 13b for separating the taken out sheets one by one and feeding them to the transport path L are provided. The transport path L has a predetermined timing after temporarily waiting for the fed paper. A registration roller 14 for supplying the image to the image forming unit 8 is provided.

  The image forming unit 8 forms an image on a sheet supplied from the manual sheet feeding unit 6 or the cassette sheet feeding unit 7, and is an image carrier disposed rotatably at a substantially central portion in the main body 2. As a photosensitive drum 15, a primary charger 16 disposed around the photosensitive drum 15, a developing device 17 as a developing unit, a transfer roller 18 and a cleaning device 19 as a transferring unit, and a laser scanner unit (above them) LSU) 20, a toner hopper 21 and the like.

  The fixing unit 9 is for fixing the toner image transferred to the sheet in the image forming unit 8 to the sheet, and includes a fixing roller 22 and a pressure roller 23 that are pressed against each other and rotated. Yes.

  Further, the paper discharge unit 10 is for discharging the paper on which the toner image is fixed in the fixing unit 9 to the outside of the main body 2, and a pair of paper discharge rollers 24 provided at the end of the conveyance path L. And a plurality of conveying guide ribs 25 in the form of longitudinal ribs for guiding the sheet conveyed through the conveying path L to the sheet discharge roller 24 and the sheet discharge tray 3 for stacking sheets discharged to the outside of the main body 2. I have.

  Next, an image forming operation of the laser beam printer 1 having the above configuration will be described.

  For example, when a print start signal is transmitted to the laser beam printer 1 from a terminal such as a personal computer (personal computer), the photosensitive drum 15 is moved in the direction of the arrow (clockwise) in FIG. ) And the surface thereof is uniformly charged to a predetermined potential by the primary charger 16. When a laser beam based on the image data transmitted from the terminal is output from the laser scanner unit 20 and irradiated onto the photosensitive drum 15, an electrostatic latent image is formed on the photosensitive drum 15. The electrostatic latent image formed on the photosensitive drum 15 is developed by the developing device 17 using toner as a developer to be visualized as a toner image.

  By the way, when cassette feeding is performed, the sheets stored in the sheet feeding cassette 11 of the cassette sheet feeding unit 7 are picked up one by one from the uppermost one by the pick roller 12, and the cassette is rotated while the direction of 180 ° is reversed. The paper is conveyed to the registration roller 14 by the paper feed roller 13a.

  In the registration roller 14, the sheet is temporarily put into a standby state and then supplied to the image forming unit 8 at a predetermined timing synchronized with the toner image on the photosensitive drum 15.

  In the image forming unit 8, the sheet supplied to the transfer nip between the photosensitive drum 15 and the transfer roller 18 is conveyed while being pressed against the photosensitive drum 15 by the transfer roller 18, thereby its surface (transfer surface). ) Is transferred to the toner image on the photosensitive drum 15. The sheet onto which the toner image has been transferred is conveyed to the fixing unit 9, and is heated and pressed in the process of being sandwiched and conveyed by the fixing roller 22 and the pressure roller 23 in the fixing unit 9. Get fixed. The toner remaining on the surface of the photosensitive drum 15 (transfer residual toner) after the transfer of the toner image onto the paper is removed by the cleaning device 19.

  Thus, the sheet on which the toner image is fixed on the surface by the fixing unit 9 is conveyed upward along the conveyance path L, guided to the sheet discharge roller 24 along the conveyance guide rib 25, and is discharged by the sheet discharge roller 24. The paper is discharged and stacked on the paper discharge tray 3 at the top of the main body 2, and a series of image forming operations is completed.

When the user manually feeds the paper, the paper set on the manual tray 4 of the manual paper feeder 6 is supplied to the registration roller 14 by the cassette paper feed roller 5, and thereafter the same process as described above. Then, an image is formed on the paper.
[Paper Feeder]
Next, the configuration of the drive system of the manual paper feed unit 6 and the cassette paper feed unit 7 constituting the paper feed device according to the present invention will be described.

  2 is a plan view of the drive system of the paper feeding device according to the present invention, FIG. 3 is a view in the direction of arrow X in FIG. 2, FIG. 4 is a perspective view of the main part of the drive system of the paper feed device, and FIG. FIG. 6 is a side view showing the operation of the manual paper feed unit, and FIG. 7 is a cross-sectional side view of the same.

  As shown in FIGS. 2 and 3, a cassette paper feed roller shaft 26 and a manual paper feed roller shaft 27 are arranged in parallel and rotatable with each other, and one cassette paper feed roller 13a is disposed on the cassette paper feed roller shaft 26. , And the rotation of the cassette paper feed roller shaft 26 is transmitted to the pick roller 12 through gears 28, 29 and 30. A clutch 31 and an idle gear 32 are provided at the axial end of the cassette paper feed roller shaft 26. The driving force from the motor 33 as a driving source is transmitted to the idle gear 32 through the gear train G.

  Therefore, when paper is fed from the cassette paper feeding unit 7, the clutch 31 is turned on, and the driving force from the motor 33 is transmitted to the idle gear 32 via the gear train G, and is transmitted from the idle gear 32 via the clutch 31. The cassette paper feed roller shaft 26 and the cassette paper feed roller 13a attached to the cassette paper feed roller shaft 26 are rotationally driven, and the rotation of the cassette paper feed roller shaft 26 is rotated by gears 28 and 29. , 30 is transmitted to the pick roller 12, and the pick roller 12 is rotationally driven, and the paper in the cassette 11 shown in FIG. 1 is fed to the registration roller 14 (see FIG. 1) by the cassette paper feed roller 13a. .

  On the other hand, the manual paper feed roller 5 is bound to the manual paper feed roller shaft 27, and a drive gear 34 is bound to one axial end of the manual paper feed roller shaft 27. Under the drive gear 34, a missing gear 35 that selectively meshes with the drive gear 34 is disposed. As shown in detail in FIG. 4, the input gear 36 is selected for the missing gear 35. The input gear 36 is meshed with the idle gear 32.

  Here, the configuration and operation of the manual sheet feeder 6 will be described with reference to FIGS.

  As shown in FIG. 5, a bottom plate 37 is provided below the manual feed roller 5 so as to be movable up and down. One end of the bottom plate 37 in the width direction (the end on the side where the drive gear 34 is provided ( A lift arm 38 and a bottom bracket 39 are attached to the left end in FIG.

  A drive shaft 40 is disposed below the drive gear 34 in parallel with the manual paper feed roller shaft 27. The drive shaft 40 is connected to a toothless gear 35 and a control cylinder 41 for driving. A cam 42 that engages with the lower surface of the lift arm 38 is attached to the end of the shaft 40.

  In the outer peripheral portion of the toothless gear 35, toothless portions 35a and 35b are formed in two rows in the width direction, and the drive gear 34 and the input gear 36 are selected for the toothless gear 35, respectively. Mesh. Note that a locking claw 41 a protrudes from a part of the outer periphery of the control cylinder 41.

  A solenoid 43 as contact / separation means is disposed below the control cylinder 41, and a distal end portion of the actuator 44 of the solenoid 43 bent in an L shape is a locking claw 41 a of the control cylinder 41. Disengage against. Here, the actuator 44 is energized by the spring 45, and the non-energized character to which the solenoid 43 is not energized has a distal end portion of the actuator 44 as shown in FIG. 5 and FIG. The control cylinder 41, the toothless gear 35 and the cam 42 are stopped at the illustrated position by engaging with 41a.

  As shown in FIG. 4, a spring 46 as an urging means is stretched on the back surface of the cam 42, and the cam 42, the toothless gear 35, and the control cylinder 41 are held by the spring 46 in FIGS. 6 and 7. Is biased in the direction of arrow A (clockwise).

  Thus, since the driving force from the motor 33 is transmitted to the input gear 36 via the gear train G and the idle gear 32, the input gear 36 is always driven to rotate. When the gear 41 and the cam 42 are stopped at the initial positions shown in FIGS. 5 and 6, the missing gear portion 35 b of the missing gear 35 faces the input gear 36, so that the input gear 36 is moved to the missing gear 35. Without meshing, the input gear 36 rotates idly and does not transmit rotation to the toothless gear 35. In the state where the toothless gear 35, the control cylinder 41 and the cam 42 are stopped at the initial positions as shown in FIGS. 5 and 6, rotational energy is accumulated in the spring 46, and the toothless gear 35 and The control cylinder 41 and the cam 42 are urged in the direction of arrow A in FIG.

  When the user manually feeds paper from the manual paper feed unit 6 configured as described above, when the paper is set on the manual feed tray 4 shown in FIG. The actuator 44 operates against the urging force of the spring 45, and its distal end is detached from the locking claw 41 a of the control cylinder 41. Then, since the rotational energy accumulated in the spring 46 is released, the toothless gear 35, the control cylinder 41, and the cam 42 are integrally rotated in the direction of arrow A in FIG.

  When the cam 42 rotates in the direction of arrow A in FIG. 7, the lift arm 38 engaged therewith pushes up the bottom plate 37, so that the paper placed on the bottom plate 37 is pressed by the manual feed roller 5. . In this state, when the drive gear 34 meshes with the toothless gear 35, the rotation of the toothless gear 35 is transmitted to the manual paper feed roller shaft 27 through the drive gear 34, and is connected to the manual paper feed roller shaft 27. The attached manual paper feed roller 5 rotates, and the paper on the bottom plate 37 is nipped between the bottom plate 37 and the manual paper feed roller 5 and fed to the registration roller 14 shown in FIG. Since the clutch 31 is OFF when manual feeding is being performed, the driving force from the motor 33 is not transmitted to the cassette paper feed roller shaft 26, and the cassette paper feed roller shaft 26 and the pick roller 12 and the cassette paper feed roller 13a do not rotate.

  When manual feeding of one sheet of paper is completed as described above, the missing gear 35 meshes with the input gear 36, so that the missing gear 35 resists the biasing force of the spring 46 together with the control cylinder 41 and the cam 42. Then, it is rotated in the counter arrow A direction (counterclockwise in FIGS. 6 and 7) and returned to the initial position shown in FIGS. 5 and 6, and the actuator 44 of the solenoid 43 is engaged with the locking claw 41a of the control cylinder 41. The tip end portion engages and rotation of the toothless gear 35, the control cylinder 41, and the cam 42 is stopped, and rotational energy is accumulated in the spring 46 again. Thereafter, the same operation is repeated, and the sheet is manually fed from the manual sheet feeder 6.

  Thus, according to the present embodiment, the driving force transmitted from the motor 33 to the cassette paper feed roller shaft 26 via the gear train G and the idle gear 32 is selectively applied to the cassette paper feed roller 13a via the clutch 31. In addition, the drive power transmission system to the pick roller 12, the cassette paper feed roller 13a, and the manual paper feed roller 5 is a single system. The drive system is simplified and space saving is realized, the number of parts is reduced, and the size and cost are reduced.

  Further, according to the present embodiment, since the idle gear 32 is arranged on the cassette paper feed roller shaft 26, the driving force from the idle gear 32 to the manual paper feed roller 5 is not affected by ON / OFF of the clutch 31. Can communicate.

  In the above description, the present invention has been described with respect to a laser beam printer and a paper feeding device provided in the laser beam printer. However, the present invention is not limited to a printer, and other arbitrary image formation such as a copying machine or a facsimile machine. Of course, the present invention can be similarly applied to the apparatus and the paper feeding apparatus provided therein.

1 is a side sectional view of an image forming apparatus (laser beam printer) according to the present invention. It is a top view of the drive system of the paper feeder concerning this invention. It is a figure of the arrow X direction of FIG. It is a perspective view of the drive system principal part of the paper feeder concerning this invention. FIG. 3 is a perspective view of a manual sheet feeding unit of the sheet feeding device according to the present invention. It is a side view showing an operation of a manual sheet feeder of the sheet feeder according to the present invention. It is a sectional side view showing an operation of a manual sheet feeding portion of the sheet feeding device according to the present invention.

Explanation of symbols

1 Laser beam printer (image forming device)
2 Printer body 3 Paper discharge tray 4 Manual feed tray 5 Manual paper feed roller 6 Manual paper feed unit 7 Cassette paper feed unit 8 Image forming unit 9 Fixing unit 10 Paper discharge unit 11 Paper feed cassette 12 Pick roller 13a Cassette paper feed roller 13b Separation Roller 14 Registration roller 15 Photosensitive drum 16 Primary charger 17 Developing device 18 Transfer roller 19 Cleaning device 20 Laser scanner unit (LSU)
DESCRIPTION OF SYMBOLS 11 Toner hopper 22 Fixing roller 23 Pressure roller 24 Paper discharge roller 25 Conveying guide rib 26 Cassette paper feed roller shaft 27 Manual paper feed roller shaft 28-30 Gear 31 Clutch 32 Idle gear 33 Motor (drive source)
34 drive gear 35 missing tooth gear 35a, 35b missing tooth portion 36 missing gear 36 input gear 37 bottom plate 38 lift arm 39 bottom bracket 40 drive shaft 41 control cylinder 41a control cylinder locking claw 42 cam 43 solenoid (contact / separation means)
44 Solenoid actuator 45, 46 Spring (biasing means)
G Gear train L Transport path

Claims (3)

In a paper feeding device that feeds paper by a cassette paper feeding roller or a manual paper feeding roller that is rotationally driven by a drive source,
A clutch and an idle gear are provided on a cassette paper feed roller shaft for rotationally driving the cassette paper feed roller, and a driving force from the drive source is selectively transmitted to the cassette paper feed roller via the clutch, and A sheet feeding device configured to transmit to the manual sheet feeding roller via an idle gear.   A toothless gear that selectively meshes with a drive gear that rotationally drives the manual feed roller, a biasing means that biases the missing gear in one rotation direction, and a gear that selectively meshes with the missing gear. An input gear for returning the toothless gear to the initial position against the biasing force of the biasing means and contact / separation means for holding / releasing the toothless gear at the initial position are provided, and the input gear is connected to the idle gear. The sheet feeding device according to claim 1, wherein the sheet feeding device is engaged. In an image forming apparatus that feeds a sheet to an image forming unit by a sheet feeding unit, transfers a toner image formed on an image carrier in the image forming unit onto the sheet, and fixes the toner image on the sheet.
3. An image forming apparatus, wherein the paper feeding means is constituted by a paper feeding device according to claim 1.

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