JP2004010192A - Sheet feeding device performing a feeding retry operation and image forming apparatus provided with the device - Google Patents

Abstract

When a tooth tip of a drive gear and a toothless gear abut against each other and supply of a transfer material cannot be performed, the abutment is released.
A sheet feeding device includes a feeding gear for rotating a supply roller for feeding a transfer material stacked on the tray from the tray, an input gear engaged with the feeding gear, and a sheet feeding device for rotating the input gear. A motor 115b, a rotation preventing unit 122 for preventing rotation of the feeding gear when the toothless portion faces the input gear, and a rotation force applied to the feeding gear when the rotation preventing unit releases rotation of the feeding gear. The rotation urging means for applying the feed gear to the input gear and the drive control means are configured to release the transfer material by a predetermined amount even after a lapse of a predetermined time after canceling the rotation prevention of the feed gear by the rotation prevention unit. And a control unit for temporarily stopping the sheet feeding motor and restarting the sheet feeding motor when it does not reach the position.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet supply device for supplying a sheet, and an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, and a multifunction machine including the sheet supply device in an apparatus main body.
[0002]
[Prior art]
The sheet supply device is provided, for example, as one of the components of the image forming apparatus in the apparatus main body of the image forming apparatus, and forms a transfer material from a transfer material loading unit on which the transfer material is loaded, and forms an image on the transfer material. It may be used as a transfer material supply device for sending out to the image forming section. Further, the sheet feeding device is provided, for example, as one of the components of the image forming apparatus in the apparatus main body of the image forming apparatus, and feeds the document from the document stacking portion on which the document is stacked toward the document reading position. It may be used as a supply device.
[0003]
A sheet supply device provided in the apparatus main body of the image forming apparatus for use in supplying the transfer material will be described. In this case, the sheet feeding device includes a feeding roller for feeding the transfer material, a driving source for rotating the feeding roller, a driving force transmitting device for transmitting the rotational force of the driving source to the feeding roller, and the like. ing.
[0004]
This driving force transmission device transmits or cuts off the driving force of the driving source to the feeding roller at a predetermined timing so that an image is formed at an appropriate position of the transfer material in the image forming unit, The transfer material can be supplied intermittently. The driving force transmission device includes an input gear that is a drive gear that is rotated by a drive source, and a feed gear that is a toothless gear that meshes with the input gear and rotates a feed roller. When the feeding roller receives the rotational force from the feeding gear of the driving force transmission device at all times, it continues to rotate and feeds the transfer material without interruption. However, as described above, the driving force transmission device needs to rotate the feed roller ON / OFF at a certain timing so that an image is formed at an appropriate position on the transfer material in the image forming unit.
[0005]
When the rotational force is transmitted to the feed gear by a gear train that constantly transmits rotational force, a clutch mechanism may be provided in the driving force transmitting device to rotate the feed roller ON / OFF. The clutch mechanism is roughly classified into a mechanism using an electromagnetic clutch, a one-turn clutch mechanism using a toothless gear and a solenoid, and the like.
[0006]
The mechanism for attaching the electromagnetic clutch to the feed gear requires a relatively small installation space, but has the disadvantage of significantly increasing the cost. For this reason, in one-rotation control of the feed roller, a clutch mechanism using a solenoid and a toothless gear is mainly used.
[0007]
The driving force transmission device has, for example, a configuration as shown in FIGS. 2 and 3 are diagrams of the embodiment of the present invention, but since the configuration of the mechanical part is substantially the same, they will be described with reference to the convenience of explanation.
[0008]
FIG. 2 shows a standby state of the feeding roller 203b serving as a pickup roller. The feeding gear 402 as a toothless gear provided with the cam 403 having the control claw portion 404 is stationary because the flapper 405 of the solenoid 407b is engaged with the control claw portion 404. In this state, even if the drive is transmitted to the input gear 401, the drive is not transmitted to the feed gear 402 because the missing tooth portion 402 a of the feed gear 402 faces the input gear 401. Has become.
[0009]
Next, the operation of the one-rotation clutch mechanism when feeding the transfer material will be described in detail.
[0010]
First, the solenoid 407b is excited to suck the flapper 405, and the locking claw 405a of the flapper 405 is removed from the control claw 404. The feed gear 402 is rotated in the direction of the arrow in FIG. 2 by the pulling force of the feed gear biasing spring 409, and when the feed gear 402 rotates by the number of missing teeth, the meshing start tooth 402 b of the feed gear 402 meshes with the feed gear 402. I do. The meshing start teeth 402b are elastically deformed in the radial direction so that the feeding gear 402 can smoothly mesh with the input gear 401. As a result, the drive of the input gear 401 is transmitted to the feed gear 402.
[0011]
Here, the solenoid 407b only needs to temporarily release the lock between the flapper 405 and the control claw portion 404, so that the solenoid 407b is in a non-excited state during one rotation of the feeding gear 402. The flapper 405 of the solenoid 407 b in a non-excited state is pulled by the flapper regulating spring 406 toward the feed gear 402. Therefore, the locking claw 405 a comes into contact with the outer periphery of the cam 403, and is in a state capable of engaging with the control claw portion 404 of the feeding gear 402. When the locking claw 405a faces the control claw 404 of the feeding gear 402 and engages with the control claw 404, the missing tooth portion 402a faces the input gear 401, so that the input gear 401 The motor stops when torque is no longer transmitted.
[0012]
As described above, the one-rotation clutch mechanism can perform one-rotation control of the feed roller 203b by exciting the solenoid 407b at a desired timing.
[0013]
[Problems to be solved by the invention]
However, depending on the timing of exciting the solenoid 407b, the one-rotation clutch mechanism in the driving force transmitting device may cause the tooth tips to abut and bite each other when the feeding gear 402 and the input gear 401 mesh as shown in FIG. The rotation of the input gear 401 and the feed gear 402 may stop.
[0014]
In this case, when the rotation of the feeding gear 402 stops, the rotation of the feeding roller 203b also stops, and the transfer material is not fed. For this reason, the control unit of the image forming apparatus including the sheet feeding device erroneously determines that a jam has occurred in the transfer material, and stops the operation of the image forming apparatus.
[0015]
Further, even if the transfer of the transfer material is performed again, the transfer of the transfer material may be retried in the image forming apparatus. However, when the input gear 401 and the feed gear 402 stop rotating due to abutment between the teeth. However, since the locking claw 405a of the flapper 405 is disengaged from the control claw portion 404, even if the solenoid 407b is re-excited, the contact between the tooth tips cannot be eliminated. Also in this case, similarly, the control unit of the image forming apparatus erroneously determines that a jam has occurred, and stops the operation of the image forming apparatus.
[0016]
It should be noted that the conventional sheet supply device has a similar problem even when used as a document supply device.
[0017]
The present invention provides a sheet feeding device that automatically performs a supply retry operation when a tooth tip of a drive gear and a toothless gear abut against each other and cannot supply a sheet, thereby canceling the abutment between tooth tips, With this device, when the sheet is not supplied because the teeth of the drive gear and the toothless gear of the sheet feeding device abut against each other, the image forming operation can be continued without erroneously determining that a jam has occurred. It is intended to provide a device.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, a sheet feeding device according to the present invention includes a sheet feeding rotating body that feeds a sheet stacked on a sheet stacking means from the sheet stacking means, and a sheet feeding rotating body having a toothless portion. A missing gear, a drive gear meshing with the missing gear, a drive source for rotating the drive gear, and preventing rotation of the missing gear when the missing tooth portion of the missing gear faces the drive gear. And a rotation urging means for applying a rotational force to the toothless gear when the rotation prevention means cancels the rotation prevention of the toothless gear so that the toothless gear meshes with the drive gear. And drive control means for controlling the drive source, wherein the drive control means keeps the seat at a predetermined position even after a predetermined time has elapsed after the rotation prevention of rotation of the toothless gear by the rotation prevention means is released. Does not reach After temporarily stopping the driving source, which is a supply retry operation to be restarted as to the driving source.
[0019]
In order to achieve the above object, a sheet feeding device according to the present invention includes a sheet feeding rotating body that feeds a sheet stacked on a sheet stacking means from the sheet stacking means, and a sheet feeding rotating body having a toothless portion. A missing gear, a drive gear meshing with the missing gear, a drive source for rotating the drive gear, and preventing rotation of the missing gear when the missing tooth portion of the missing gear faces the drive gear. And a rotation urging means for applying a rotational force to the toothless gear when the rotation prevention means cancels the rotation prevention of the toothless gear so that the toothless gear meshes with the drive gear. And drive control means for controlling the drive source, wherein the drive control means keeps the seat at a predetermined position even after a predetermined time has elapsed after the rotation prevention of rotation of the toothless gear by the rotation prevention means is released. Does not reach After temporarily reversed the drive source, which is a supply retry operation to normal rotation so as to to the driving source.
[0020]
The sheet feeding device according to the present invention is configured to notify the user of an abnormal state when the sheet does not reach a predetermined position even after a predetermined time has elapsed after the drive control unit causes the drive source to perform a supply retry operation. Means.
[0021]
The sheet supply device of the present invention includes a sheet detection unit that is installed at the predetermined position and detects the sheet.
[0022]
The driving source in the sheet feeding device of the present invention is a stepping motor.
[0023]
In order to achieve the above object, an image forming apparatus according to the present invention includes a sheet stacking unit on which sheets are stacked, a sheet feeding device that supplies the sheets from the sheet stacking unit, and the sheet fed by the sheet feeding device. Image forming means for forming an image on the sheet supply device, wherein the sheet supply device is a sheet supply device that performs any one of the supply retry operations described above.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
A sheet supply apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet supply apparatus in an apparatus main body, for example, a color printer will be described with reference to the drawings.
[0025]
Note that the sheet supply device of the present embodiment can be incorporated into the image forming apparatus as one of the components of the image forming apparatus. The image forming apparatus forms an image on a transfer material. The image forming apparatus includes a printer, a copier, a facsimile, and a multifunction peripheral thereof. Although the sheet feeding apparatus according to the present embodiment is incorporated as one of the components of the color printer in the main body of the color printer, it can be incorporated as one of the components in a copying machine, a facsimile, and the like. Therefore, the device to be incorporated is not limited to the color printer.
[0026]
The sheet supply device of the present embodiment is provided in a color printer and is used as a transfer material supply device that supplies a sheet, for example, a transfer material to an image forming unit. When the sheet supply device of the present embodiment is provided in an image forming apparatus having a document reading function, the sheet supply device can also be used as a document supply device that supplies a sheet, for example, a document to a document reading position. . Therefore, the sheet supply device of the present embodiment is not limited to being used only as a transfer material supply device.
[0027]
(Color printer)
FIG. 1 is a cross-sectional view of a color printer, which is an image forming apparatus, cut along a conveying direction of a sheet, for example, a transfer material.
[0028]
The color printer 100 includes a cassette sheet supply unit 202b for accommodating the transfer material Pb, a multi-sheet supply tray 202a into which the transfer material Pa is manually fed by the user, and a cassette sheet supply unit 202b for the transfer material Pa and Pb. And a sheet supply unit 219 to be supplied from the multi-sheet supply tray 202a, an image forming unit 218 for performing image processing, for example, an image forming unit 218, a fixing unit 214, and the like.
[0029]
The color pudding main body 101 can open and close the inside of the color printer 100 with an upper cover 212a and a lower cover 212b so that maintenance and inspection can be performed. The opening / closing of the cover is detected by a cover opening / closing detection sensor 109.
[0030]
The image forming unit 218 includes four photosensitive drums 215a, 215b, 215c, and 215d corresponding to respective colors of magenta, cyan, yellow, and black (hereinafter, the reference numeral “215” is used when collectively referring to the photosensitive drums). A charger 217a, 217b, 217c, 217d for uniformly charging the surface of each photoreceptor drum (hereinafter, the symbol "217" is used when collectively referring to the chargers); Optical units 117 a, 117 b, 117 c, and 117 d as exposure means for forming an electrostatic latent image on the photosensitive drum 215 (hereinafter, the optical units are collectively referred to as “117”) and an electrostatic latent image Developing units 216a, 216b, 216c and 216d for adhering toner to visualize as a toner image (hereinafter, reference numeral "216" is used when developing units are collectively referred to). Is performed), and transfer rollers 208a, 208b, 208c, and 208d as transfer means for transferring the toner image on the photosensitive drum 215 onto the transfer materials Pa and Pb (hereinafter, the transfer roller is generally referred to as "208"). ) Etc. The charger 217 and the developing device 216 are arranged around the photosensitive drum 215 in order according to the rotation direction of the photosensitive drum 215.
[0031]
Here, each of the photosensitive drums 215, the charger 217, and the developing unit 216 are integrally formed as a cartridge, and the process cartridges 206a, 206b, 206c, and 206d (hereinafter, the process cartridges are collectively referred to by reference numeral "206"). To form).
[0032]
The transfer materials Pa and Pb supplied by the sheet supply unit 219 are transported from the lower side in FIG. 1 (upstream in the transport direction of the transfer material) to the upper side (downstream side) in FIG. During this time, the transfer materials Pa and Pb are appropriately detected by the registration sensor 110, the pre-fixing sensor 111, and the paper discharge sensor 112 provided in the transport path. In synchronization with the timing at which the sensors 110, 111, and 112 detect the transfer materials Pa and Pb, the control unit 102, which will be described later, controls the operation of each image forming process of the image forming unit 218, and is transferred by the process cartridge 206 by the process cartridge 206. A color image is formed by sequentially superimposing and transferring toner images of each color on the materials Pa and Pb in the order of magenta, cyan, yellow, and black.
[0033]
The color toner images superimposed and transferred on the transfer materials Pa and Pb are fused and fixed on the surfaces of the transfer materials Pa and Pb by heating and pressing the transfer materials Pa and Pb by the fixing device 214. After that, the transfer materials Pa and Pb are discharged to the discharge tray 210.
[0034]
When an image is also formed on the other surface of the transfer materials Pa and Pb, the control unit 102 controls the discharge roller pair 209 to synchronize with the timing at which the paper discharge sensor 112 detects the rear ends of the transfer materials Pa and Pb. The flapper 119 is inverted to guide the transfer materials Pa and Pb to the inversion path 123. The transfer materials Pa and Pb guided to the reversing path 123 are conveyed in the conveying path 201 by the pair of reversing conveying rollers 211a, 211b and 211c, and conveyed to the image forming unit 218 again.
[0035]
The image forming unit 218 also forms a color toner image on the surface opposite to the transfer materials Pa and Pb. Then, the fixing device 214 melts and fixes the color toner image on the transfer materials Pa and Pb. Finally, the discharge roller pair 209 discharges the transfer materials Pa and Pb to the discharge tray 210 and stacks them.
[0036]
(Sheet feeding device)
FIG. 2 is a schematic configuration diagram of the one-rotation clutch mechanism 121 in the sheet feeding device 120 that feeds and rotates the sheet feeding roller 203b of the sheet feeding unit 219 of the color printer 100.
[0037]
First, the sheet supply device 120 will be schematically described. The sheet supply device 120 is used as a device for supplying the transfer material Pb of the cassette sheet supply tray 202b.
[0038]
The sheet supply device 120 is a sheet supply rotating body that feeds out, for example, a transfer material Pb, which is a sheet stacked unit, for example, a sheet loaded on a cassette sheet supply tray 202b shown in FIG. 1 from the cassette sheet supply tray 202b. The feeding roller 203b shown, a missing gear for rotating the feeding roller 203b, for example, a feeding gear 402, a driving gear meshing with the feeding gear 402, for example, an input gear 401, and a drive for rotating the input gear 401 For example, a paper feed motor 115b which is a source and a rotation preventing means which prevents rotation of the feeding gear 402 when a missing tooth portion 402a which is a missing tooth portion of the feeding gear 402 faces the input gear 401. When the rotation preventing portion 122 releases the rotation inhibition of the feeding gear 402, the rotation of the feeding gear 402 For example, a feed-gear urging spring 409, which is a rotation urging unit that meshes the feed gear 402 with the input gear 401, and a drive control unit that controls the paper feed motor 115b, for example, a control shown in FIG. And a unit 102. The rotation prevention unit 122 includes a cassette paper feeding solenoid 407b, a flapper 405, a flapper regulating spring 406, and the like.
[0039]
When the transfer material Pb does not reach a predetermined position even after a lapse of a predetermined time after the rotation prevention unit 122 releases the rotation prevention of the feeding gear 402, the sheet feeding device 120 controls the sheet feeding by the control unit 102. After the motor 115b is stopped once, it is restarted so that the sheet feeding motor 115b performs a supply retry operation. As a result, the sheet feeding device 120 can automatically cancel the abutting state between the teeth of the input gear 401 and the sheet feeding gear 402 as shown in FIG.
[0040]
Next, the sheet feeding device 120 will be described in detail. FIG. 2 shows a standby state of the feeding roller 203b serving as a pip-up roller. The feeding gear 402, which is a toothless gear provided with the cam 403 having the control claw 404, is stationary with the locking claw 405a of the flapper 405 of the cassette paper feeding solenoid 407b locked to the control claw 404.
[0041]
In this state, even if the rotational force of the paper feed motor 115 b is transmitted to the input gear 401, the rotational force is applied to the feed gear 402 because the toothless portion 402 a of the feed gear 402 faces the input gear 401. It is not transmitted. However, the input gear 401 continues to rotate by the paper feed motor 115b. In the present embodiment, a stepping motor is used as the sheet feeding motor 115b, but the invention is not limited to the stepping motor. The paper feed motor 115b is configured to rotate by being supplied with an excitation pulse by the paper feed control unit 107 shown in FIG.
[0042]
Next, the operation of the one-rotation clutch mechanism 121 when feeding the transfer material will be described in detail.
[0043]
First, the control unit 102 shown in FIG. 4 causes the sheet feeding control unit 107 to excite the cassette sheet feeding solenoid 407b. The cassette sheet feeding solenoid 407b sucks the flapper 405 and removes the locking claw 405a from the control claw 404. The feed gear 402 rotates in the direction of the arrow in FIG. 2 by the pulling force of the feed gear biasing spring 409.
[0044]
Then, the teeth of the engagement start portion 402b of the feeding gear 402 mesh with the input gear 401, and the feeding gear 402 starts rotating. Since the engagement start portion 402b has elasticity, it is smoothly engaged with the input gear 401. Here, the feeding gear 402 is rotated by the traction force of the feeding gear urging spring 409 and the rotating force of the input gear 401 after the rotation prevention state by the flapper 405 is released, and therefore, the cassette paper feeding solenoid 407b is Only the operation of removing the locking claw 405a from the control claw portion 404 may be performed, and the non-excitation state may be maintained during one rotation of the feeding gear 402.
[0045]
Since the cassette paper feeding solenoid 407b is in the non-excited state, the flapper 405 is pulled by the flapper regulating spring 406, and the locking claw 405a can be locked to the control claw portion 404 at any time. When the toothless portion 402a faces the input gear 401, the feeding gear 402 continues to rotate by the input gear 401, and receives no rotational force from the input gear 401, but is pulled by the feeding gear urging spring 409. The rotation is continued, and the rotation is stopped by the locking claw 405a being locked to the control claw portion 404. The stopped feeding gear 402 is stopped with the toothless portion 402a facing the input gear 401 and receiving the traction force in the direction of the arrow by the feeding gear biasing spring 409, so that the locking claw 405a is controlled by the control claw. When removed from the portion 404, it rotates immediately and can mesh with the input gear 401.
[0046]
In the above operation, while the feeding gear 402 makes one rotation, the feeding roller 203b integrated with the feeding gear 402 also makes one rotation. Since the feed roller 203b is formed in a half-moon shape, the transfer material Pb is sent out from the cassette sheet supply tray 202b by the arc portion 203ba during one rotation, and is sent to the sheet feed roller pair 204b. The cutout portion 203bb, which is a cutout flat portion, is stopped facing the transfer material. The transfer material sent to the pair of paper feed / conveyance rollers 204b is pulled out of the cassette sheet supply tray 202b by the pair of paper feed / conveyance rollers 204b, and sent to the image forming unit 218.
[0047]
As described above, since the sheet feeding device 120 can control the single rotation of the feeding roller 203b by exciting the cassette feeding solenoid 407b, by exciting the cassette feeding solenoid 407b at a desired timing, One transfer material can be fed.
[0048]
The sheet supply device described above is a sheet supply device for a cassette sheet supply tray that controls the rotation of the supply roller 203b of the cassette sheet supply tray 202b. For example, the sheet supply device 120 for a multi-sheet supply tray that controls the rotation of the rotating member, for example, the supply roller 203a, has the same configuration and the same operation. The feed roller 203a is configured to rotate by receiving a rotational force of, for example, a feed motor 115a, which is a drive source shown in FIG.
[0049]
It is not always necessary to provide a sheet feeding device for the multi-sheet feeding tray. The transfer material Pa may be directly fed to the pair of paper feed rollers 204a manually. Also, the sheet feeding motor 115a and the multi-tray sheet feeding solenoid 407a shown in FIG. 4 constitute a sheet feeding device for a multi-sheet feeding tray.
[0050]
(Control block of color printer)
FIG. 4 is a control block diagram of the color printer of the present embodiment.
[0051]
The color printer main body 101 is connected to the host computer 104 directly or via a network. The print data created by the host computer 104 is received by the controller 103 and converted into an image signal. The controller 103 inquires of the control unit 102 about the status, confirms that the printer is in a printable state, and then issues a print start instruction to the control unit 102. Upon receiving the print start instruction, the control unit 102 connects to the transport control unit 105, the fixing device drive control unit 106, and the optical units 117a, 117b, 117c, and 117d (hereinafter, the optical units are collectively referred to as " 117 ”), the photosensitive drum drive control unit 108 and the paper feed control unit 107 are controlled, and printing preparation such as activation of each load is started.
[0052]
The transport control unit 105 drives the transport motor 113 to rotate the transfer rollers 208a, 208b, 208c, 208d and the pair of reverse transport rollers 211a, 211b. The fixing device drive control unit 106 drives the fixing motor 114 to rotate the fixing device 214 and the discharge roller pair 209.
[0053]
The paper supply control unit 107 drives the paper supply motors 115a and 115b, the cassette paper supply solenoid 407b, and the multi-tray paper supply solenoid 407a to supply paper feed rollers 203a and 203b serving as pickup rollers, and paper supply conveyance rollers. The driving of the pair 204a, 204b and the registration roller pair 205 is controlled.
[0054]
The photosensitive drum drive control unit 108 controls the drive of the process cartridges 206a, 206b, 206c, 206d by driving the photosensitive drum motors 116a, 116b, 116c, 116d.
[0055]
When the preparation for printing is completed, the control unit 102 issues a sheet feeding instruction to the sheet feeding control unit 107 and starts feeding the transfer materials Pa and Pb from the sheet feeding unit 219.
[0056]
At this time, the control unit 102 transitions to the printing state, and notifies the controller 103 of the transition to the printing state. When the leading end of the supplied transfer material Pb is detected by, for example, a registration sensor 110 which is a sheet detection unit, the control unit 102 sends a print start signal to the controller 103 after a predetermined time. The controller 103 that has received the print start signal outputs an image signal in synchronization with the print start signal. The image signal output by the controller 103 is modulated by the optical unit 117 into a laser beam on / off signal, and is exposed on the photosensitive drum 215 by the laser beams 207a, 207b, 207c, 207d from the optical unit 117.
[0057]
As the transfer material Pb is transported along the transport path, the image forming unit 218 is controlled to form a color image on the transfer material Pb. When the image forming process is normally completed and the trailing end of the transfer material Pb is detected by the paper discharge sensor 112, the control unit 102 determines that the printing has been completed normally, and returns to the printable state. To the controller 103. On the other hand, during printing, the control unit 102 detects a jam using the registration sensor 110, the pre-fixing sensor 111, and the paper ejection sensor 112.
[0058]
Hereinafter, as an example of the jam detection, a procedure of the detection of the paper feed delay jam and the supply retry operation will be described. The supply retry operation includes a supply retry operation according to two embodiments described below. Even if the feeding retry operation is different, the configuration of the sheet feeding apparatus itself is substantially the same as the above-described configuration, and thus the description of the configuration is omitted.
[0059]
(Supply Retry Operation of First Embodiment)
FIG. 5 is a flowchart showing a procedure for detecting a paper feed delay jam and retrying the paper feed (supply retry operation).
[0060]
The paper feed start (S301) is performed by the control unit 102 exciting the cassette paper feed solenoid 407b to be in a non-excited state after a predetermined time t1. The predetermined time t1 may be a time shorter than the time during which the feeding gear 402 makes one rotation.
[0061]
The control unit 102 monitors the registration sensor 110 for a predetermined time t2 after the start of sheet feeding. The predetermined time t2 may be a time longer than the designed maximum value of the time that the leading end of the transfer material Pb reaches the registration sensor 110 after the start of sheet feeding.
[0062]
When the registration sensor 110 detects the leading end of the transfer material Pb before the predetermined time t2 elapses, the control unit 102 determines that the transfer material Pb has been normally fed (S308), and continues the image forming operation. I do. If the registration sensor 110 does not detect the leading end of the transfer material Pb by the elapse of the predetermined time t2, the control unit 102 determines that paper feeding has failed for some reason and shifts to paper feeding retry. (S304). Some causes include abutting between the teeth of the feeding gear 402 and the input gear 401 as shown in FIG.
[0063]
FIG. 6 is a flowchart showing the operation of the sheet feeding apparatus of the present embodiment for the sheet feeding retry (supply retry operation, S304) shown in FIG.
[0064]
In the paper feed retry, the control unit 102 temporarily stops the paper feed motor 115b (S601), restarts it after a predetermined time t3 (S603), and excites the cassette paper feed solenoid 407b (S604), and This is performed by setting the state to the non-excitation state after t1 (S606). During the predetermined time t3, when the paper feeding motor 115 is stopped, the mesh between the input gear 401 and the feeding gear 402 is temporarily released due to the backlash of the gear train in which the driving force is transmitted from the paper feeding motor 115 to the input gear 401. A short period of time is sufficient.
[0065]
The control unit 102 monitors the registration sensor 110 for a predetermined time t2 after the paper feed retry. If the registration sensor 110 detects the leading end of the transfer material Pb before the predetermined time t2 has elapsed, the control unit 102 releases the state in which the teeth of the feeding gear 402 and the input gear 401 are in contact with each other, It is determined that the transfer material Pb has been normally fed (S308), and the image forming operation is continued.
[0066]
If the registration sensor 110 does not detect the leading end of the transfer material Pb before the predetermined time t2 elapses, the control unit 102 determines that the transfer material Pb Determines that a paper jam has occurred inside the sheet supply unit 219, and determines that a paper feed delay has occurred (S307). When the control unit 102 determines that a paper feed delay jam has occurred, the control unit 102 stops all the loads on the color printer 100 to stop the image forming operation, and notifies the controller 103 of the occurrence of the jam. The controller 103 notifies the occurrence of a jam through the display panel 118 on the color printer main body 101.
[0067]
The sheet feeding apparatus excites the cassette sheet feeding solenoid 407b without temporarily stopping the sheet feeding motor 115b at the time of sheet feeding retry, for example, when the sheet feeding is delayed due to a separation failure of the transfer material Pb during sheet feeding. In many cases, normal feeding can be performed by performing a supply retry operation only with the use of a single sheet.
[0068]
However, when the first paper feed is performed, as shown in FIG. 3, both the feed gear 402 and the input gear 401 may stop due to the tooth tips of the feed gear 402 and the input gear 401 abutting and biting. is there. In such a state, the lock of the flapper 405 of the cassette paper feeding solenoid 407b with the control claw 404 of the cam 403 is released, and the cassette flapper 405 rides on the cam 403. At the time of the above-described paper feed retry, by temporarily stopping the paper feed motor 115b, the torque applied to the input gear 401 is released. As a result, the input gear 401 rotates slightly in the reverse direction due to the backlash of the gear train from the paper feed motor 115b to the input gear 401, and the abutting state between the input gear 401 and the feed gear 402 is released.
[0069]
On the other hand, since the feeding gear 402 is urged by the sheet feeding gear urging spring 409, rotation of the feeding gear 402 starts again in the direction of the arrow (clockwise) shown in FIG. Thereafter, the input gear 401 also starts rotating by restarting the paper feed motor 115b. However, at this time, the positional relationship between the feed gear 402 and the input gear 401 is different from that at the time of the end of the contact, so that the feed gear 402 and the input gear 401 do not come into contact with each other and operate normally. And the paper feeding operation is performed.
[0070]
Accordingly, when the rotation of the gear stops due to the abutment between the teeth of the feeding gear 402 and the input gear 401 and the transfer material cannot be supplied, the sheet feeding device 120 stops the sheet feeding motor 115b at the sheet feeding retry. The paper feed retry (supply retry operation) is automatically performed to release the end contact state, and the transfer material can be quickly supplied.
[0071]
Further, the color printer 100 including the sheet supply device 120 can continue the image forming operation without erroneously determining that a jam has occurred when the transfer material is not supplied, thereby reducing the frequency of stopping the printer. Thus, the image forming efficiency is not reduced. In addition, it is convenient for the user.
[0072]
(Supply Retry Operation of Second Embodiment)
The supply retry operation according to the second embodiment is performed by temporarily rotating the sheet feeding motor 115b in the reverse direction.
[0073]
FIG. 5 is a flowchart showing a procedure for detecting a paper feed delay jam and retrying the paper feed.
[0074]
The paper feed start (S301) is performed by the control unit 102 exciting the cassette paper feed solenoid 407b to be in a non-excited state after a predetermined time t1. The predetermined time t1 may be a time shorter than the time during which the feeding gear 402 makes one rotation.
[0075]
The control unit 102 monitors the registration sensor 110 for a predetermined time t2 after the start of sheet feeding. The predetermined time t2 may be a time longer than the designed maximum value of the time that the leading end of the transfer material Pb reaches the registration sensor 110 after the start of sheet feeding.
[0076]
When the registration sensor 110 detects the leading end of the transfer material Pb before the predetermined time t2 elapses, the control unit 102 determines that the transfer material Pb has been normally fed (S308), and continues the image forming operation. I do. If the registration sensor 110 does not detect the leading end of the transfer material Pb by the elapse of the predetermined time t2, the control unit 102 determines that paper feeding has failed for some reason and shifts to paper feeding retry. (S304).
[0077]
FIG. 7 is a detailed flowchart of the paper feed retry according to the present embodiment.
[0078]
In the paper feed retry, the control unit 102 temporarily stops the paper feed motor 115b (S701), rotates the paper feed motor 115b in the reverse direction by a predetermined step s1, and then restarts the paper feed motor 115b in the normal rotation (S704). This is performed by exciting the sheet feeding solenoid 407b (S705) and setting it to a non-excited state after a predetermined time t1 (S707). The predetermined step s1 may be any number of steps to the extent that the engagement between the feeding gear 402 and the input gear 401 is released.
[0079]
The control unit 102 monitors the registration sensor 110 for a predetermined time t2 after the paper feed retry. If the registration sensor 110 detects the leading end of the transfer material Pb before the predetermined time t2 elapses, it is determined that the transfer material Pb has been normally fed (S308), and the image forming operation is continued.
[0080]
If the registration sensor 110 does not detect the leading end of the transfer material Pb before the predetermined time t2 has elapsed, the control unit 102 determines that the transfer material Pb has a paper jam inside the sheet supply unit 219, A paper feed jam is set (S307). When the control unit 102 determines that a paper feed delay jam has occurred, the control unit 102 stops all the loads on the color printer 100 to stop the image forming operation, and notifies the controller 103 of the occurrence of the jam. The controller 103 notifies the occurrence of a jam through the display panel 118 on the color printer main body 101.
[0081]
Note that the motor may be reversed for a time corresponding to the predetermined step without using a stepping motor.
[0082]
Therefore, when the rotation of the gear stops due to the abutment between the teeth of the feeding gear 402 and the input gear 401 and the transfer material cannot be supplied, the sheet feeding device 120 sets the sheet feeding motor 115b to the sheet feeding retry for a predetermined time. By automatically performing a paper feed retry (supply retry operation) for reversing only the step or a time corresponding to the predetermined step, the hit state can be more reliably released, and the transfer material can be supplied promptly.
[0083]
Further, the color printer 100 including the sheet supply device 120 can continue the image forming operation without erroneously determining that a jam has occurred when the transfer material is not supplied, thereby reducing the frequency of stopping the printer. Thus, the image forming efficiency is not reduced. In addition, it is convenient for the user.
[0084]
The supply retry operation described above is for the sheet supply device for the cassette sheet supply tray that controls the rotation of the supply roller 203b of the cassette sheet supply tray 202b, but the rotation control of the supply roller 203a of the multi-sheet supply tray 202a is performed. The supply retry operation of the sheet supply device 120 for the multi-sheet supply tray can be performed in the same manner.
[0085]
The forward rotation, stop, and reverse rotation of the toothless gear 401 are performed by the forward rotation, stoppage, and reverse rotation of the motors 115a and 115b. It may be performed by operating a rotational force transmission mechanism provided therebetween.
[0086]
【The invention's effect】
The sheet feeding apparatus of the present invention temporarily stops the sheet feeding motor during the sheet feeding retry operation and releases the end of the tooth gap between the toothless gear and the driving gear, thereby reducing the frequency of occurrence of sheet feeding failure. And the sheet can be supplied reliably.
[0087]
In the sheet feeding apparatus of the present invention, the sheet feeding motor is once rotated reversely during the sheet feeding retry operation to release the end of the tooth gap between the toothless gear and the drive gear, thereby reducing the frequency of occurrence of sheet feeding failure. And the sheet can be supplied reliably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a color printer, which is an image forming apparatus according to an embodiment of the present invention, taken along a conveying direction of a sheet, for example, a transfer material.
FIG. 2 is a diagram illustrating a standby state of a feeding roller in the sheet feeding apparatus according to the exemplary embodiment of the present invention.
3 is a diagram illustrating a state in which teeth of a feeding gear and an input gear abut on each other in the sheet feeding device of FIG. 2;
FIG. 4 is a schematic control block diagram of the printer according to the embodiment of the present invention.
FIG. 5 is a flowchart for schematically explaining a jam detection and a feed retry operation in the sheet feeding apparatus of the present invention.
FIG. 6 is a flowchart illustrating a supply retry operation according to the first embodiment of the present invention.
FIG. 7 is a flowchart illustrating a supply retry operation according to a second embodiment of the present invention.
[Explanation of symbols]
Pa transfer material
Pb transfer material (sheet)
100 color printer (image forming device)
101 Color Printer
102 control unit (drive control means)
107 Paper feed control unit
110 registration sensor (sheet detection means)
115a Paper feed motor (drive source)
115b Paper feed motor (drive source)
118 Display panel
120 sheet feeding device
121 One-turn clutch mechanism
122 Rotation blocking part (rotation blocking means)
202a Multi-sheet supply tray (sheet stacking means)
202b Cassette sheet supply tray (sheet stacking means)
203a, 203b feeding roller (rotating body for sheet feeding)
203ba arc
203bb notch
204a, 204b paper feed roller pair
215a, 215b, 215c, 215d Photoconductor drum
218 Image forming unit (image forming unit)
401 Input gear (drive gear)
402 Feeding gear (missing gear)
402a Missing part (missing part)
402b meshing start tooth
403 cam
404 control claw
405 Flapper
405a locking claw
406 Flapper control spring
407a Multi-tray paper feed solenoid
407b Cassette feed solenoid
409 Feeding gear biasing spring (rotation biasing means)

Claims (6)

A sheet supply rotating body that sends out the sheets stacked on the sheet stacking unit from the sheet stacking unit,
A toothless gear having a toothless portion for rotating the sheet supply rotating body,
A drive gear that meshes with the toothless gear;
A drive source for rotating the drive gear;
Rotation prevention means for preventing rotation of the toothless gear when the toothless portion of the toothless gear faces the drive gear;
When the rotation preventing unit releases the rotation prevention of the toothless gear, a rotation urging unit that applies a rotational force to the toothless gear and meshes the toothless gear with the drive gear,
Drive control means for controlling the drive source,
The drive control means, after releasing the rotation prevention of the toothless gear by the rotation prevention means, once the sheet does not reach a predetermined position even after a predetermined time has elapsed, after temporarily stopping the drive source, A sheet supply apparatus for performing a supply retry operation, wherein the drive source is configured to perform a supply retry operation for restarting. A sheet supply rotating body that sends out the sheets stacked on the sheet stacking unit from the sheet stacking unit,
A toothless gear having a toothless portion for rotating the sheet supply rotating body,
A drive gear that meshes with the toothless gear;
A drive source for rotating the drive gear;
Rotation prevention means for preventing rotation of the toothless gear when the toothless portion of the toothless gear faces the drive gear;
When the rotation preventing unit releases the rotation prevention of the toothless gear, a rotation urging unit that applies a rotational force to the toothless gear and meshes the toothless gear with the drive gear,
Drive control means for controlling the drive source,
The drive control means, after releasing the rotation prevention of the toothless gear by the rotation prevention means, when the sheet does not reach a predetermined position even after a predetermined time has elapsed, after the drive source is once reversely rotated, A sheet supply apparatus for performing a supply retry operation, wherein the drive source is configured to perform a supply retry operation for normal rotation. After the drive control unit causes the drive source to perform a supply retry operation, when the sheet does not reach a predetermined position even if a predetermined time has elapsed, a notification unit that notifies a user of an abnormal state is provided. 3. The sheet feeding apparatus according to claim 1, wherein the sheet retry operation is performed. 4. The sheet feeding apparatus according to claim 1, further comprising a sheet detecting unit installed at the predetermined position to detect the sheet. 5. 4. The sheet feeding apparatus according to claim 1, wherein the driving source is a stepping motor. 5. Sheet loading means on which sheets are loaded,
A sheet supply device that supplies the sheet from the sheet stacking unit,
Image forming means for forming an image on the sheet supplied by the sheet supply device,
The image forming apparatus according to claim 1, wherein the sheet supply device performs the supply retry operation according to claim 1.

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