JP2006096564A - Paper feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder and an image forming device having a drive transmission mechanism without using an electric clutch, and capable of preventing feed of accompanied paper. <P>SOLUTION: The paper feeders 11, 12, 13 and 14 have a paper feeding unit 30 having a motor 31 and the drive transmission mechanism, and its paper feeding unit 30 synchronously drives a separation roller 22 and a carrier roller 24. Thus, the separation roller is surely driven when carrying paper, and can prevent duplicate feed and accompanied feed of the paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper feeding device and an image forming apparatus used for a copying machine, a printer, a facsimile, a printing machine, and the like.

  In the paper feeding device, various separation methods have been proposed for feeding sheets one by one, and a representative one is a friction separation method. A paper feeding device that employs this frictional separation (hereinafter referred to as FRR) system includes a feed roller that rotates in the paper feeding direction, and a torque limiter that is pressed against the feed roller and rotated in the direction opposite to the paper feeding direction. When one sheet is sandwiched between the two rollers, the separation roller is rotated by a torque limiter. When two or more sheets are sandwiched, the separation roller rotates in the direction opposite to the sheet feeding direction. Thus, the sheet feeding device can separate and convey the sheets one by one.

  In the image forming apparatus in which the FRR sheet feeding devices described above are arranged in multiple stages, when driven by independent sheet feeding units owned by each sheet feeding device, the feed roller, separation roller, and conveyance roller are driven by separate driving sources. There are problems in terms of cost, space, etc. Therefore, a single driving source is used to drive the feed roller, separation roller, and transport roller by disconnecting them with an electric clutch such as switching with an electromagnetic clutch or solenoid. The clutch has a possibility that a continuous disconnection time variation or a continuous disconnection failure due to slippage may occur depending on the size of the continuous drive load, and as a result, a jam or the like is generated, which adversely affects the sheet conveyance.

JP-A-8-59000

  Patent Document 1 discloses a paper feeding device that hardly causes such a problem. The paper feeders provided in multiple stages each have an independent paper feed unit, which feeds using a one-way clutch, which is a mechanical clutch, by switching between forward and reverse rotation by one forward / reverse rotation motor. A roller, a separation roller, and a conveyance roller are driven. Specifically, the feed roller, the separation roller, and the transport roller are driven by normal rotation of the motor, and only the transport roller is driven at high speed when switching to reverse rotation.

  However, in the paper feeding device described in Patent Document 1, when the motor is switched from normal rotation to reverse rotation, the drive of the separation roller together with the feed roller is stopped. If they are in close contact with each other, there is a problem that the following paper is fed at the same time, and it is impossible to prevent the feeding paper feeding.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding device and an image forming apparatus that can solve the above-described conventional problems, have a drive transmission mechanism that does not use an electric clutch, and can prevent the feeding paper feeding. It is said.

  In order to solve the above problems, the present invention provides a paper feed tray for storing stacked paper, a feed roller that is driven to rotate in the direction of feeding the paper, and a pressure limiter that is in pressure contact with the feed roller at least during paper feeding. A feed roller, a separation roller that is rotationally driven in a direction to return the paper via a paper feed, and a transport member provided downstream of the feed roller in the paper feed direction, the feed roller, the separation roller, and the transport member; A paper feeding device is provided which includes a paper feeding unit having a driving source for driving them, and the paper feeding unit includes a drive transmission mechanism for interlocking the separation roller and the conveying member.

In the sheet feeding device of the present invention, it is effective that the drive source of the sheet feeding unit is a single motor capable of switching the rotation direction.
Further, in the sheet feeding device of the present invention, the drive transmission mechanism includes a first transmission path for transmitting the drive to the separation roller when the drive source is rotated to one side, and the drive source is rotated to the other side. It is effective to have a second transmission path that transmits the drive to the separation roller.

  Furthermore, in the sheet feeding device of the present invention, the drive transmission mechanism transmits the drive source to the one side by rotating the drive source to one side, and transmits the drive source to the other side. It is effective to transmit the drive to drive the separation roller and the conveying member without transmitting the drive to the feed roller by rotating to.

  Furthermore, in the paper feeding device according to the present invention, it is effective that the driving of the separation roller and the conveying member by the paper feeding unit is continued from the paper feeding start to the paper feeding end by the driving source. is there.

  Furthermore, in the sheet feeding device of the present invention, it is effective that the rotation direction of the drive source is switched from one to the other while the sheet is held between the feed roller and the separation roller. .

  Furthermore, in the paper feeding device of the present invention, it is effective that the drive transmission mechanism is composed of a mechanical member including a drive transmission member such as a gear and a belt and a one-way clutch.

  Furthermore, in the paper feeding device of the present invention, the first transmission path transmits the drive of the drive source to the feed roller, and the drive transmitted to the feed roller is transmitted to the separation roller through a gear, The second transmission path is effective when the drive of the drive source is directly transmitted to the separation roller.

  Furthermore, in the sheet feeding device of the present invention, the first transmission path and the second transmission path transmit the drive of the drive source to the separation roller by drive transmission by a gear, and at that time, the gear of the first transmission path It is effective when the number is an odd number greater than the gears of the second transmission path.

Furthermore, in the paper feeding device of the present invention, it is effective that the paper feeding unit can be attached to and detached from the paper feeding device body.
In order to solve the above problems, the present invention is a paper feed tray for storing stacked paper, a feed roller that is rotationally driven in the direction of feeding out the paper, and the pressure contact with the feed roller at least during paper feeding. A plurality of sheet feeding devices having a separation roller that is rotationally driven in a direction to return the sheet via a torque limiter and a conveying member provided downstream of the feed roller in the sheet feeding direction are arranged in multiple stages in the vertical direction. In the image forming apparatus, a sheet fed from a sheet feeding apparatus other than the uppermost sheet is conveyed toward the image forming unit via a conveying member of the sheet feeding apparatus arranged at an upper level than the sheet feeding apparatus. An image forming apparatus characterized by the above is proposed.

  In the image forming apparatus according to the aspect of the invention, the paper feeding device includes the feed roller, the separation roller, and the conveying member, and a paper feeding unit having a drive source for driving them, and the paper feeding device is an upper stage paper feeding device. It is effective if the paper feed units of adjacent paper feed devices are drive-coupled so that the drive is not transmitted to the paper feed unit of the paper device, but is transmitted to the paper feed unit of the lower paper feed device. Is.

  Further, in the image forming apparatus of the present invention, the uppermost sheet feeding apparatus and the sheet feeding apparatus that performs sheet feeding are driven in conjunction with the separation roller and the transport member, and do not perform other sheet feeding. The apparatus is effective when only the conveying member is driven without driving the separation roller.

  Furthermore, in the image forming apparatus of the present invention, the paper feeding device includes the feed roller, the separation roller, and the conveying member, and a paper feeding unit having a drive source for driving them, and each of the paper feeding devices. The paper feeding units are independent of each other, and the paper feeding unit of the paper feeding device that performs paper feeding is driven with a predetermined power, and the paper feeding device of the upper stage is higher than the paper feeding device that performs paper feeding. It is effective when the paper unit is driven with power smaller than the predetermined power.

  Furthermore, in the image forming apparatus of the present invention, it is effective if the power supply to the paper feeding unit of the paper feeding device below the paper feeding device that performs the paper feeding is stopped.

  Furthermore, in the image forming apparatus of the present invention, the paper feeding device has contact / separation means for bringing the separation roller into contact with and separating from the feed roller, and the contact / separation means is used when the paper feeding device performs paper feeding. Only when the separating roller is actuated to contact the feed roller, it is effective.

  According to the configuration of claim 1, the sheet feeding device includes the sheet feeding unit including the drive source and the drive transmission mechanism, and the sheet feeding unit drives the separation roller and the conveyance member in conjunction with each other. During the conveyance of the paper, the separation roller is always driven, so that the double feeding and the feeding of the paper can be prevented.

  According to the configuration of the second aspect, the sheet feeding unit can be driven by one motor whose driving source is rotationally driven in two directions, and a space-saving sheet feeding device can be provided at low cost.

  According to the configuration of the third aspect, the drive transmission mechanism of the paper feed unit separates the first transmission path for transmitting the drive to the separation roller by rotation to one of the drive sources and the drive by the rotation of the drive source to the other. Since the second transmission path for transmitting to the roller is provided, the drive can be transmitted to the separation roller regardless of the rotation direction of the drive source.

According to the fourth aspect of the present invention, the driving of the feed roller can be controlled by switching the rotation direction of the driving source, and the separation roller and the conveying member can always be driven.
According to the configuration of the fifth aspect, since the driving of the separation roller is continued from the start of the paper feed to the end of the paper feed, it is possible to reliably prevent the double feed and the accompanying feed.

  According to the configuration of the sixth aspect, since the rotation direction of the drive source is switched while the sheet is sandwiched between the feed roller and the separation roller, it is possible to prevent the next sheet from being fed. it can.

  According to the configuration of the seventh aspect, since the drive transmission mechanism transmits the drive with a mechanical member composed of a drive transmission member such as a gear and a belt and a one-way clutch and does not use an electric clutch, It is possible to prevent the continuous disconnection failure due to the variation or slippage.

  According to the configuration of claim 8, the first transmission path transmits the drive of the drive source to the feed roller, the drive transmitted to the feed roller is transmitted to the separation roller via the gear, and the second transmission path is driven. Since the drive of the source is directly transmitted to the separation roller, the drive transmission loss can be suppressed with a minimum drive system, and the drive source can be minimized and inexpensively configured.

  According to the configuration of the ninth aspect, the first transmission path and the second transmission path transmit the drive of the driving source to the separation roller by drive transmission by gears, and the number of gears of the first transmission path is the second transmission path. Therefore, the separation roller drive shaft can be reliably rotated in a predetermined direction by a drive source capable of switching the rotation direction.

According to the configuration of the tenth aspect, since the paper feeding unit can be attached to and detached from the paper feeding device main body, maintenance, inspection, and the like can be easily performed.
According to the configuration of the eleventh aspect, the sheet feeding devices are arranged in parallel in the vertical direction, and the sheet fed from the sheet feeding unit is fed to the image forming unit via the transport member of the sheet feeding unit above the sheet feeding unit. Can be conveyed.

  According to the structure of the twelfth aspect, the paper feeding units of the paper feeding device are drivingly connected to each other, and the driving of each paper feeding unit is not transmitted to the upper paper feeding unit, but is transmitted to the lower paper feeding unit. Therefore, paper can be transported by feeding the paper from the lower paper feed unit by driving the paper feed unit and the uppermost paper feed unit.

  According to the configuration of the thirteenth aspect, the separation roller driving shaft and the conveying member are driven so that the conveying member is driven by the rotational driving of the separating roller driving shaft, and the separating roller driving shaft is not driven by the rotational driving of the conveying member. Since they are connected, it is possible to drive only the conveying member by driving the upper sheet feeding unit and to avoid wasteful driving.

  According to the configuration of the fourteenth aspect, the sheet feeding units of the sheet feeding unit are independent from each other, and the sheet feeding unit of the sheet feeding unit that feeds the sheet is driven by the set predetermined power, and The paper feed unit in the upper stage from the paper unit can be driven with a power smaller than a predetermined power, and power consumption can be saved.

  According to the configuration of the fifteenth aspect, the lower sheet feeding device than the device that performs the sheet feeding stops the power supply itself to the sheet feeding unit, so that the power consumption can be further saved.

  According to the configuration of the sixteenth aspect, the sheet feeder has contact / separation means for bringing the separation roller into contact with and separating from the feed roller, and the contact / separation means feeds the separation roller only when the sheet feeder performs sheet feeding. Since the roller is operated so as to contact the roller, it is possible to reduce a driving load in the sheet feeding device that performs only the conveyance without feeding.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic explanatory diagram of an image forming apparatus including a paper feeding device according to the present invention.
In FIG. 1, reference numeral 1 denotes an image forming apparatus main body, and an upper portion in the apparatus main body has a photosensitive drum 3 as an image carrier, and forms an image based on a known electrophotographic process. Part 2 is provided. Below the image forming unit 2, a sheet feeding unit 10 including multi-stage, in this example, four-stage sheet feeding devices 11, 12, 13, and 14 is provided. A sheet is fed from one of the apparatuses 11, 12, 13, and 14 toward the image forming unit. The image forming apparatus main body 1 of this example is provided with a manual sheet feeding device 4 and a reversing unit 5 for both sides.

  In the image forming apparatus described above, a sheet fed from the sheet feeding unit 10 or the manual sheet feeding unit 4 is sent to the registration roller 6 and is formed on the surface of the photosensitive drum 3 by the image forming unit 2 by the registration roller 6. The toner image is fed to the transfer unit at the same timing. The transfer belt 7 is provided in the transfer section, and the unfixed toner image is transferred to the paper sent to the transfer section, and is transported by the travel of the transfer belt 7 and transported to the fixing device 8. The sheet conveyed to the fixing device 8 is fixed as an unfixed toner image as a permanent image by the action of, for example, heating and pressing. After fixing, the sheet is selected and conveyed to either the paper discharge unit 9 or the reversing unit 5. The

FIG. 2 is an explanatory diagram showing an enlarged main part of the paper feeding device according to the present invention, and FIG. 3 is an explanatory diagram showing an expanded drive system of the paper feeding unit of the paper feeding device.
2 and 3, the paper feeding devices 11 to 14 adopt the FRR method, and have a paper feeding tray 20 for stacking and storing paper P and a paper feeding unit 30 for feeding the stacked paper one by one. . The paper feeding unit 30 is rotationally driven in a direction to return the paper via a torque limiter 25 (shown in FIG. 3), and a feed roller 21 that is rotationally driven in the direction of feeding out the paper P. A separation roller 22, a pickup roller 23 that feeds stacked sheets, and a conveyance roller 24 as a conveyance member that conveys the sheet P fed by the feed roller 21 are provided. When the paper feeding operation is started, the paper feeding devices 11 to 14 feed the paper P in the direction of arrow A by the pickup roller 23 to which the driving of the feed roller 21 is transmitted, and the nip between the feed roller 21 and the separation roller 22. Sandwiched between. At this time, if one sheet is fed, the separation roller 22 is rotated by the conveying force of the feed roller 21, the sheet is fed as it is, and is conveyed to the registration roller 7 by the conveying roller 24. Even if a plurality of sheets are fed, since the separation roller 22 is given a predetermined torque in the return direction, the separation roller 22 rotates in the return direction to return the sheet in contact with the uppermost sheet. Only the paper is separated and fed by the feed roller 21. Reference numerals 27 and 28 denote transport driven rollers that are in contact with the transport roller 24.

  The paper feeding unit 30 of the paper feeding devices 11 to 14 includes a motor 31 as a drive source, and a stepping motor that can rotate in two directions is used as the motor. The drive of the motor 31 is transmitted to the feed roller 21, the separation roller 22, and the transport roller 24 through a drive transmission mechanism. The feed roller 21, the separation roller 22, the transport roller 24, and the drive transmission mechanism are supported by a unit machine frame 29 of the paper feed unit 30.

Next, the drive transmission mechanism described above will be described in detail.
As shown in FIG. 3, a timing pulley 35 is fixed to the output shaft 32 of the motor 31, a timing pulley 36 with a gear 39 is provided on the drive shaft 33 of the feed roller 21, and a timing is provided on the drive shaft 34 of the separation roller 22. A pulley 37 is fixed, and a timing belt 38 is wound around the timing pulleys 35, 36, and 37. At this time, the timing belt wound around the timing pulleys 35, 36 and 37 has a triangular shape as shown in FIG.

  The motor 31 is driven from the timing pulley 35 via the timing belt 38 and the geared timing pulley 36 to the drive shaft 33 of the feed roller 21, and from the timing pulley 35 via the timing belt 38 and the timing pulley 37. Each is transmitted to the shaft 34. The geared timing pulley 36 and the timing pulley 37 to which the drive is transmitted are provided with one-way clutches 36a and 37a, respectively, and the drive shaft 34 of the separation roller 22 is engaged with the gear 39 of the geared pulley 36. 40, and the gear 40 is also provided with a one-way clutch 40a. A one-way clutch 36a provided in the geared timing pulley 36 locks the rotation direction of the timing belt 38 when the motor 31 rotates in one direction (hereinafter referred to as the forward rotation direction) and transmits the rotation. However, the same direction is a direction in which the one-way clutch 37a provided in the timing pulley 37 does not transmit driving. Further, in the one-way clutch 40a provided in the gear 40, the direction in which the motor 31 is driven in the forward rotation direction and the drive shaft 33 of the feed roller 21 rotates is the direction in which the drive is transmitted. For this reason, when the motor 31 is rotationally driven in the forward rotation direction, the drive of the motor 31 is rotationally driven via the output shaft 32, the timing belt 38, and the geared timing pulley 36, The drive is transmitted to the drive shaft 34 of the separation roller 22 via the geared timing pulley 36 and the gear 40. During the forward rotation, the one-way clutch 37a rotates in the idle direction, so that the drive via the timing pulley 37 is not transmitted to the drive shaft 34 of the separation roller 22. Accordingly, both the feed roller 21 and the separation roller 22 are rotationally driven when the motor 31 is driven forward. A path for transmitting the drive to the drive shaft 34 of the separation roller 22 via the timing belt 38, the geared timing pulley 36, and the gear 40 is the first drive transmission path of the present embodiment.

  Further, when the motor 31 is rotationally driven in the other direction (hereinafter referred to as the reverse direction), the direction in which the timing belt 38 travels at this time is the direction in which the one-way clutch 36a does not transmit the rotation as described above. The drive shaft 33 of the feed roller 21 is not driven to rotate. On the other hand, since the drive shaft 34 of the separation roller 22 is in a direction in which the one-way clutch 37a transmits the drive, the motor 31 is driven via the timing belt 38 and the timing pulley 37 which are the second drive transmission path. The shaft 34 is rotationally driven. Note that the one-way clutch 40a is in a direction that does not transmit rotation with respect to the rotation of the drive shaft 34 of the separation roller 22, and therefore the gear 40 does not rotate. No transmission is made to the drive shaft 33 of the feed roller 21 via the timing pulley 36 with gear.

  Thus, the drive shaft 33 of the feed roller 21 is configured to rotate only when the motor 31 rotates in the forward direction, and the drive shaft 34 of the separation roller 22 is driven to rotate regardless of whether the motor 31 rotates in the forward direction or the reverse direction. It is configured to be. The drive shaft 34 of the separation roller 22 is provided with a gear 41, and the gear 41 meshes with a gear 42 provided on the driven shaft 43 of the separation roller 22 to which the separation roller 22 is attached. Thus, the separation roller 22 can be adjusted by the tooth surface pressure of the gears 41 and 42 by providing the separation roller 22 via the driven shaft 43 instead of being directly provided on the drive shaft 34.

  The drive shaft 34 of the separation roller 22 is provided with a timing pulley 44, while the roller shaft 45 of the transport roller 24 is provided with a gear 48 that meshes with the gear 47 of the geared timing pulley 46. A timing belt 49 is wound around the timing pulley 44 and the geared timing pulley 46. With this configuration, when the drive shaft 34 of the separation roller 22 is rotationally driven, the transport roller 24 is also rotationally driven. Therefore, when the separation roller 22 is driven, the transport roller 24 is rotationally driven.

  In the sheet feeding devices 11 to 14 having the sheet feeding unit 30 configured as described above, when a sheet feeding command is issued, the motor 31 is rotated forward, whereby the feed roller 21, the separation roller 22, and the conveying roller 24 are respectively turned on. It is rotationally driven in a predetermined direction. Since the pickup roller 23 is drivingly connected to the drive shaft 33 of the feed roller 21 via an idle gear (not shown), the pickup roller 23 is also driven to rotate in a predetermined direction by the forward rotation of the motor 31.

  The paper fed out by the drive of the pickup roller 23 is sandwiched between the feed roller 21 and the separation roller 22 and then sandwiched between the transport rollers 24. When the paper is fed up to this point, the feed roller 21 is not driven to rotate. The paper can be fed even if it is in the state of being rotated. Further, the rotation of the feed roller 21 needs to be turned off while the paper to be fed is sandwiched between the feed roller 21 and the separation roller 22. Therefore, in the present embodiment, as shown in FIG. 2, a sensor 26 is provided on the downstream side in the paper conveyance direction of the conveyance roller 24 and in the vicinity thereof, and when the sensor 26 detects the leading edge of the paper, the motor 31 is adjusted correctly. Switching from reverse to reverse.

  When the motor 31 is driven in reverse, as described above, the feed roller 21 is not rotationally driven, but the separation roller 22 and the conveying roller 24 are continuously driven. As described above, since the separation roller 22 and the transport roller 24 are rotationally driven during the paper feeding operation, even if the subsequent paper is in close contact with a part of the paper to be transported due to static electricity or the like, Since the paper is returned by the separation roller 22, it is possible to prevent the feeding paper. Note that driving the separation roller 22 and the transport roller 24 together can be driven by different driving sources (motors). However, if the driving is performed by one driving source as in the above embodiment, the cost, This is advantageous in terms of space. The gear 48 is provided with a one-way clutch 48, and the direction in which the rotation of the gear 48 is transmitted to the shaft 45 of the conveying roller 24 is the locking direction. Therefore, even if the transport roller 24 rotates through the transported paper, the rotation is not transmitted to the gear 48.

Next, the paper feeding unit 30 of this embodiment is configured to be detachable from the paper feeding device body, and an example thereof will be described with reference to FIG.
In FIG. 5, the unit machine casing 29 of the paper feeding unit 30 includes a front plate portion 29a and a rear plate portion 29b. An L-shaped mounting bracket 70 is fixed to the front plate portion 29a, and two pins 71 and 72 extending in the axial direction of the feed roller 21 are fixed to the rear plate portion 29b. On the other hand, a rear plate 75 indicated by a chain line and an elongated plate-like front fixing plate 76 extending in the vertical direction are provided in the sheet feeder main body, and holes 77 and 78 into which the pins 71 and 72 are inserted are provided in the rear plate 75. Is formed. In this case, the hole 82 is formed in a long hole shape extending in the horizontal direction. A screw hole 73 is formed in the mounting bracket 70, and a screw hole (not shown) is formed in the front fixing plate 76 at a position corresponding to the screw hole 73.

  In the sheet feeding device configured as described above, pins 71 and 72 are inserted into the holes 77 and 78 on the back side in the depth direction of the image forming apparatus in the sheet feeding unit 30 and supported by the rear plate 75, and the front side is The bolt 74 is inserted into the screw hole 73 of the mounting bracket 70 and the screw hole of the front fixing plate 76 and fixed. Therefore, when removing the paper feeding unit 30 from the paper feeding device, if the bolt 74 is removed and the paper feeding unit 30 is moved in the direction of arrow B, the unit rotates about the position of the pin 72 as a fulcrum. After moving to a position where it does not hit the front fixing plate 76, the paper feeding unit 30 can be removed from the paper feeding device by being pulled out in the direction of arrow C. Note that the hole 82 is formed in a long hole shape so that the paper feeding unit 30 can be easily rotated in the direction of arrow B in the above detaching operation.

  Thus, since the paper feeding unit 30 is detachably attached to the paper feeding devices 11 to 14, the paper feeding unit 30 can be completely taken out from the paper feeding device for inspection, cleaning, and part replacement. it can. Note that the paper feeding unit 30 may be attached in the reverse order of the above detaching operation.

  By the way, in the image forming apparatus shown in FIG. 1, the paper feeding devices 11 to 14 are provided in multiple stages in the vertical direction, and when the paper is fed from the lower paper feeding device, the transport roller 24 of the upper paper feeding device is moved. Without driving, the sheet cannot be conveyed to the image forming unit 2. In this case, the upper sheet feeder than the apparatus that performs the sheet feeding needs only to rotate the conveyance roller 24 and the separation roller 22 is not affected, but the pickup roller 23 and the feed roller 21 are not rotated. Must be.

  In the image forming apparatus, the paper feeding units 30 of the paper feeding devices 11 to 14 are independent from each other. Therefore, when paper feeding is performed from the lowermost paper feeding device 14, all the paper feeding devices 11 to 14 are driven. To do. At that time, only the lowermost sheet feeding device 14 switches the motor 31 from the normal forward rotation to the reverse rotation driving in the middle, but the other three-stage sheet feeding devices drive the motor 31 in the reverse rotation from the beginning. Thus, by controlling the motor 31 of each of the paper feeding devices 11 to 14, the paper fed from the lowermost paper feeding unit can be fed to the image forming unit 2. At this time, it is possible to save energy if the paper can be transported without being driven by the power of the predetermined power similar to the device that feeds the motor 31 to the paper feeding device that drives the transport roller 24 but does not feed paper. It is advantageous.

  Therefore, the sheet feeding devices 11 to 14 used in the image forming apparatus are provided with contact / separation means for moving the separation roller 22 in the direction of arrow D to contact and separate from the feed roller 21 as shown in FIG. Next, an example of contact / separation means will be described with reference to FIG.

  In FIG. 7, the contact / separation means applies a pressure lever 80 and a pressure lever 80 to urge the separation roller 22 in a direction in which it is pressed against the feed roller 21 by the pulling force of the pressure spring 81. And a release lever 90 for releasing the applied pressure. As shown in FIGS. 7 and 8, the pressure lever 80 is rotatably attached to a unit machine frame (not shown) via a support shaft 82, and a push-up portion 83 that pushes up the separation roller 22 to the pressure lever 80. And a push-down portion 84 that pushes down the separation roller 22 is formed. Further, the pressure spring 81 urges the pressure lever 80 in the clockwise direction in FIG. The pressurizing lever 80 urges the pressing force by the push-up portion 83 coming into contact with the roller 43 a fixed to the driven shaft 43 of the separation roller 22.

  The release lever 90 is rotatably mounted on a unit machine frame (not shown) via a support shaft 91, and the release lever 90 is rotated counterclockwise in FIG. Power is energized. A plunger 96 of a solenoid 95 is rotatably connected to one end of the release lever 90 via a pin 97, and the other end of the release lever 90 is connected to the pressure lever 80 as shown in FIG. It is made to contact | abut to the formed contact part 85. FIG.

  In the contact / separation means having such a configuration, when the solenoid 95 is in the OFF state, the release lever 90 pushes the contact portion 85 of the pressure lever 80 by the elastic action of the release spring 92, and the pressure lever 80 is separated from the push-down portion 84. The roller 22 contacts the driven shaft 43, and the separation roller 22 is held away from the feed roller 21 against the action of the pressure spring 81. When the solenoid 95 is switched from the off state to the on state, the plunger 96 is pulled in the direction of arrow E in FIG. 7 and the release lever 90 is shown by an arrow F centering on the support shaft 91 against the action of the release spring 92. It is rotated clockwise. The rotation direction of the release lever 90 is a direction away from the contact portion 85, so that the pressure lever 80 is rotated clockwise by the action of the pressure spring 81, and the separation roller 22 is moved via the push-up portion 83. The separation roller 22 is pushed up and pressed against the feed roller 21.

  The contact / separation means can contact / separate the separation roller 22 to / from the feed roller 21 by turning on / off the solenoid 95 as described above. By providing the contact / separation means with such a configuration in the paper feeding device, the paper feeding device that does not feed paper can drive the separation roller 22 and the transport roller 24 by separating the separation roller 22 from the feed roller 21. Unnecessary load on the separation roller 22 is eliminated, and the separation roller 22 can be driven with less power than a device that performs sheet feeding. Specifically, when the predetermined power supplied to the paper feeding device that performs paper feeding is 1.3 A / phase at maximum with respect to the stepping motor 31 (hereinafter referred to as high power), the maximum smaller than the predetermined power. Even if the mode is switched to 0.9 A / phase (hereinafter referred to as low power), the sheet can be conveyed without any trouble. In FIG. 9, the sheet feeders 11 to 14 have four stages, and when the sheets are fed from the respective sheet feeders, a device driven with high power indicated by “H” and a low power indicated by “L”. It is a table | surface which shows the apparatus to drive. In FIG. 9, the lower apparatus than the sheet feeding apparatus that performs sheet feeding is indicated by “x”, and this sheet feeding apparatus stops power supplied to the sheet feeding unit 30, thereby providing a more advantageous power saving effect. can get.

The image forming apparatus configured as described above can save power consumption when the lower paper feed units 12 to 14 are selected.
FIG. 10 is an explanatory diagram showing a configuration of a paper feeding unit according to another embodiment of the present invention, and FIG. 11 is an explanatory diagram showing a paper feeding unit of each of the paper feeding units 11-14. In addition, the same code | symbol is attached | subjected to the same member as the said embodiment. In this embodiment, since the mechanism from the motor 31 to the drive shaft 34 of the separation roller 22 is the same as that of the above embodiment, the description thereof is omitted.

  A geared timing pulley 50 is disposed below the geared timing pulley 46, and the timing belt 49 is wound around three pulleys: a timing pulley 44, a geared timing pulley 46, and a geared timing pulley 50. Yes. The lower relay gear 52 meshes with the gear 51 of the geared timing pulley 50. Further, a gear 54 is provided on the roller shaft 45 of the transport roller 24 so as to substantially overlap the gear 48, and the gear 54 meshes with the upper relay gear 53. Further, the lower relay gear 52 in the upper paper feed unit is engaged with the upper relay gear 53 in the lower paper feed unit. The gear 54 is provided on the roller shaft 45 of the transport roller 24 via a one-way clutch 54a. The one-way clutch 54a has a direction when the gear 47 of the geared timing pulley 46 and the upper relay gear 53 rotate. Since the driving direction is transmitted, the conveying roller 24 rotates. However, since the rotation of the roller shaft 45 itself of the transport roller 24 is in a direction in which the one-way clutch 54 a is not transmitted to the upper relay gear 53 or the gear 47, the upper relay gear 53 is rotationally driven by the rotation of the transport roller 24. Absent.

  In the sheet feeding device configured as described above, when the upper relay gear 53 is rotated by receiving a drive from the lower relay gear 52 of the upper sheet feeding unit, the transport roller 24 is rotated. When the gear 48 of the roller shaft 45 rotates, the geared timing pulley 46 having the gear 47 engaged therewith rotates, and the timing belt 49 travels in the clockwise direction. Therefore, since the geared timing pulley 50 rotates, the lower relay pulley 52 that meshes with the gear 51 of the geared timing pulley 50 also rotates. The driving by the travel of the timing belt 49 is also transmitted to the drive shaft 34 of the separation roller 22, but the one-way direction in which the travel of the timing belt 49 in the clockwise direction is not transmitted to the drive shaft 34 of the separation roller 22. By providing the clutch 44a, the drive shaft 34 is not rotated.

  As described above, when the lower relay gear 52 of the upper paper feed unit is rotated, the transport roller 24 in the lower paper feed unit can be rotationally driven. For example, when paper is fed from the lowermost paper feed unit 14, the uppermost and lowermost paper feed units 11, 14 are driven, and the intermediate paper feed units 12, 13 are not driven. The conveyance rollers 24 of the units 12 and 13 are rotated by receiving the drive of the uppermost sheet feeding unit 11. Accordingly, as shown in the table of FIG. 12, since the sheet can be fed only by driving only the uppermost sheet feeding unit 11 and the selected sheet feeding unit, the effect can be expected as the number of sheet feeding stages increases. . In the uppermost sheet feeding unit 11, the motor 31 only rotates in the reverse direction unless the sheet feeding unit is selected.

  In the above embodiment, the motor 30 is driven to rotate the feed roller 21 and the separation roller 22 by using a belt, but this can also be performed by a gear. FIG. 13 shows the configuration of the paper feed unit 30 driven by a gear.

  In FIG. 13, a gear 60 is provided on the output shaft 32 of the motor 31, and the gear 60 meshes with the drive shaft 34 of the separation roller 22 and the gear 61 via a one-way clutch 61a. The gear 61 is engaged with a small-diameter gear 63b of a two-stage gear provided with a drive shaft 33 of the feed roller 21 via an idler gear 62 and via a one-way clutch 63a. The large-diameter gear 63c, which is a two-stage gear, meshes with the gear 40 via the one-way clutch 40a on the drive shaft 34. In this case, the one-way clutch 61a is a direction in which the rotation of the gear 61 due to the reverse rotation of the motor 31 is locked to transmit the rotation, and is idle in the forward rotation direction. In the one-way clutch 63a, the direction in which the motor 31 is driven in the forward rotation direction and the drive shaft 33 of the feed roller 21 rotates is the direction in which the drive is transmitted. Further, in the one-way clutch 40a, the direction in which the gear 40 is driven via the two-stage gear is set to be locked.

  When the sheet feeding unit 30 configured in this way is rotated in the forward direction of the motor 31, the sheet feeding unit 30 is formed via the gear 61, the idler gear 62 and the two-stage gear, so that the drive shaft 33 of the feed roller 21 is rotationally driven. Further, the gear 40 meshing with the two-stage gear rotates to drive the drive shaft 34 of the separation roller 22 to rotate. When the motor 31 is rotated in the reverse rotation direction, the drive shaft 34 of the separation roller 22 is rotationally driven from the gear 61, but the drive shaft 33 of the feed roller 21 is driven by a one-way clutch 63a provided in the two-stage gear. The direction is not transmitted, so it is not rotated.

  Also in this embodiment, the same effect as the above-described embodiment can be obtained. In the present embodiment, the downstream side in the drive transmission direction from the drive shaft 34 of the separation roller 22 is the same as that in the above embodiment, and thus detailed description thereof is omitted.

1 is a schematic diagram illustrating an example of an image forming apparatus including a sheet feeding device according to the present invention. It is explanatory drawing which expands and shows the principal part of the paper feeder which concerns on this invention. FIG. 3 is an explanatory diagram showing a drive system of a paper feeding unit of a paper feeding device in an expanded manner. It is front explanatory drawing of the paper feed unit shown in FIG. FIG. 4 is a perspective view illustrating a configuration example in which a paper feeding unit can be attached to and detached from a paper feeding device body. It is explanatory drawing which shows the contact / separation operation | movement of a separation roller. It is a perspective view which shows an example of the contacting / separating means which a separation roller contacts / separates. It is explanatory drawing which shows the action | operation of the contacting / separating means of FIG. It is a table | surface figure which shows the example of a switching of the drive current in a multistage paper feed unit. It is explanatory drawing which shows the structure of the paper feed unit in other embodiment of this invention. It is front explanatory drawing of the paper feed unit of FIG. It is a table | surface figure which shows the example of drive on / off in a multistage paper feed unit. It is explanatory drawing which shows the structure of the paper feed unit in further another embodiment of this invention.

Explanation of symbols

2 Image forming unit 10 Paper feeding unit 11, 12, 13, 14 Paper feeding device 21 Feed roller 22 Separating roller 24 Conveying roller 30 Paper feeding unit 31 Motor

Claims (16)

A paper feed tray for storing stacked paper, a feed roller that is driven to rotate in the direction of feeding out the paper, and a pressure roller that is in pressure contact with the feed roller at least during paper feeding, and is driven to rotate in a direction to return the paper via a torque limiter. A sheet feeding device having a separating roller and a conveying member provided downstream of the feed roller in the sheet feeding direction,
A feed unit having a feed roller, a separation roller, a transport member, and a drive source for driving the feed roller, the feed unit, and a drive transmission mechanism for interlocking the separation roller and the transport member; Characteristic paper feeder.   2. The paper feeding device according to claim 1, wherein the drive source of the paper feeding unit is a single motor capable of switching a rotation direction.   3. The sheet feeding device according to claim 2, wherein when the drive source is rotated to one side, the drive transmission mechanism has a first transmission path that transmits the drive to the separation roller, and the drive source is rotated to the other side. And a second transmission path for transmitting the drive to the separation roller.   4. The sheet feeding device according to claim 2, wherein the drive transmission mechanism transmits the drive source so as to drive the feed roller, the separation roller, and the conveying member by rotating the drive source in one direction. The sheet feeding device transmits the drive to the feed roller so as to drive the separation roller and the conveying member without rotating the feed to the other.   3. The sheet feeding device according to claim 1, wherein the driving of the separation roller and the conveying member by the sheet feeding unit is continued from the start of feeding to the end of feeding by the driving source. A paper feeder.   6. The sheet feeding device according to claim 2, wherein the switching of the rotation direction from one of the driving sources to the other is performed while the sheet is sandwiched between the feed roller and the separation roller. A paper feeding device characterized by that.   5. The paper feeding device according to claim 1, wherein the drive transmission mechanism is constituted by a mechanical member including a drive transmission member such as a gear and a belt and a one-way clutch. .   4. The sheet feeding device according to claim 3, wherein the first transmission path transmits the drive of the drive source to the feed roller, and the drive transmitted to the feed roller is transmitted to the separation roller through a gear, The sheet feeding device, wherein the second transmission path transmits the drive of the driving source directly to the separation roller.   9. The sheet feeding device according to claim 3, wherein the first transmission path and the second transmission path transmit driving of the driving source to the separation roller by drive transmission by a gear, and the first transmission path at that time The number of gears is an odd number greater than the number of gears in the second transmission path.   The paper feeding device according to claim 1, wherein the paper feeding unit is attachable to and detachable from a paper feeding device main body. A paper feed tray for storing stacked paper, a feed roller that is driven to rotate in the direction of feeding out the paper, and a pressure roller that is in pressure contact with the feed roller at least during paper feeding, and is driven to rotate in a direction to return the paper via a torque limiter. In an image forming apparatus in which a plurality of sheet feeding devices having a separating roller and a conveying member provided downstream of the feed roller in the sheet feeding direction are arranged in multiple stages in the vertical direction,
Image formation in which a sheet fed from a sheet feeding device other than the topmost sheet is conveyed toward an image forming unit via a conveyance member of a sheet feeding device arranged at an upper level than the sheet feeding device. apparatus.   12. The image forming apparatus according to claim 11, wherein the paper feeding device includes the feed roller, the separation roller, and a conveying member, and a paper feeding unit having a drive source for driving them, the paper feeding device being an upper stage. The paper feed units of adjacent paper feed devices are drive-coupled so that the drive is not transmitted to the paper feed unit of the paper feed device, and the drive is transmitted to the paper feed unit of the lower paper feed device. An image forming apparatus.   13. The image forming apparatus according to claim 12, wherein the uppermost sheet feeding apparatus and the sheet feeding apparatus that performs sheet feeding are driven in conjunction with the separation roller and the transport member, and do not perform other sheet feeding. The image forming apparatus according to claim 1, wherein only the conveying member is driven without driving the separation roller.   12. The image forming apparatus according to claim 11, wherein the paper feeding device includes the feed roller, the separation roller, and a conveying member, and a paper feeding unit having a drive source for driving them, and each of the paper feeding devices. The paper feeding units are independent of each other, and the paper feeding unit of the paper feeding device that performs paper feeding is driven with a predetermined power, and the paper feeding device of the upper stage is higher than the paper feeding device that performs paper feeding. The image forming apparatus, wherein the paper unit is driven with power smaller than the predetermined power.   The image forming apparatus according to claim 14, wherein the power supply to the paper feeding unit of the paper feeding device lower than the paper feeding device that performs the paper feeding is stopped.   16. The image forming apparatus according to claim 14, wherein the paper feeding device has contact / separation means for contacting / separating the separation roller with the feed roller, and the contact / separation means performs paper feeding by the paper feeding device. An image forming apparatus, wherein the separation roller is operated so as to abut against the feed roller only during

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