US20210292116A1 - Conveyance device and image forming apparatus - Google Patents
Conveyance device and image forming apparatus Download PDFInfo
- Publication number
- US20210292116A1 US20210292116A1 US17/191,854 US202117191854A US2021292116A1 US 20210292116 A1 US20210292116 A1 US 20210292116A1 US 202117191854 A US202117191854 A US 202117191854A US 2021292116 A1 US2021292116 A1 US 2021292116A1
- Authority
- US
- United States
- Prior art keywords
- sheet
- roller
- separation
- conveyance
- drive source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000926 separation method Methods 0.000 claims abstract description 198
- 238000001514 detection method Methods 0.000 claims description 9
- 230000001965 increasing effect Effects 0.000 claims description 8
- 238000012546 transfer Methods 0.000 description 36
- 238000010586 diagram Methods 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 9
- 230000008859 change Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 230000002265 prevention Effects 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000012840 feeding operation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007645 offset printing Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H3/00—Separating articles from piles
- B65H3/02—Separating articles from piles using friction forces between articles and separator
- B65H3/06—Rollers or like rotary separators
- B65H3/0669—Driving devices therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H3/00—Separating articles from piles
- B65H3/46—Supplementary devices or measures to assist separation or prevent double feed
- B65H3/52—Friction retainers acting on under or rear side of article being separated
- B65H3/5246—Driven retainers, i.e. the motion thereof being provided by a dedicated drive
- B65H3/5253—Driven retainers, i.e. the motion thereof being provided by a dedicated drive the retainers positioned under articles separated from the top of the pile
- B65H3/5261—Retainers of the roller type, e.g. rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H7/00—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles
- B65H7/02—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors
- B65H7/06—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed
- B65H7/12—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed responsive to double feed or separation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/10—Rollers
- B65H2404/14—Roller pairs
- B65H2404/145—Roller pairs other
- B65H2404/1451—Pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/10—Rollers
- B65H2404/14—Roller pairs
- B65H2404/147—Roller pairs both nip rollers being driven
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
- B65H2511/40—Identification
- B65H2511/416—Identification of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2513/00—Dynamic entities; Timing aspects
- B65H2513/10—Speed
- B65H2513/11—Speed angular
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2513/00—Dynamic entities; Timing aspects
- B65H2513/50—Timing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2513/00—Dynamic entities; Timing aspects
- B65H2513/50—Timing
- B65H2513/512—Starting; Stopping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2515/00—Physical entities not provided for in groups B65H2511/00 or B65H2513/00
- B65H2515/30—Forces; Stresses
- B65H2515/32—Torque e.g. braking torque
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2515/00—Physical entities not provided for in groups B65H2511/00 or B65H2513/00
- B65H2515/70—Electrical or magnetic properties, e.g. electric power or current
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2557/00—Means for control not provided for in groups B65H2551/00 - B65H2555/00
- B65H2557/20—Calculating means; Controlling methods
- B65H2557/264—Calculating means; Controlling methods with key characteristics based on closed loop control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2801/00—Application field
- B65H2801/03—Image reproduction devices
- B65H2801/06—Office-type machines, e.g. photocopiers
Definitions
- Exemplary aspects of the present disclosure relate to a conveyance device and an image forming apparatus.
- Cut-sheet feeding devices including a multi-sheet feed prevention mechanism and capable of not only prolonging the lifespan of a feed roller but also reducing stress to be applied to a cut sheet are known.
- Such a cut-sheet feeding device includes a device for detecting a friction coefficient between sheets, a device for detecting the frequency of feeding of a cut sheet with feeding of another sheet, a device for detecting a cut-sheet conveyance speed in the course of sheet feeding, and a controller.
- the controller changes and controls sheet handling capability in the multi-sheet feed prevention system based on a combination of detection results provided by the three detection devices.
- sheet feeding devices that separate and feed sheets one by one are known. Such a sheet feeding device is provided to reliably prevent multi-sheet feeding and non-feeding. In addition, the sheet feeding device is provided to determine multi-sheet feeding or a thick sheet.
- a sheet feeding device includes a separator, a thickness detector, and a controller.
- the separator includes a feed roller that conveys a sheet in a conveyance direction and a reverse roller disposed opposite the feed roller to separate sheets conveyed between the feed roller and the reverse roller one by one.
- the thickness detector detects a thickness of the sheets to be separated by the separator.
- the controller controls a push-back force of the reverse roller based on detection information about the sheet thickness detected by the thickness detector.
- an improved conveyance device that includes a sheet stacker, a pickup roller, a feed roller, a first drive source, a first encoder, a first drive controller, a separation roller, a second drive source, a second encoder, a second drive controller, a separation pressure provider, and a torque estimation device.
- the sheet stacker is a stacker on which sheets are stacked.
- the pickup roller contacts a top sheet of the sheets stacked on the sheet stacker, and rotates in a sheet conveyance direction.
- the feed roller rotates to feed the sheet in the sheet conveyance direction.
- the first drive source rotates the pickup roller and the feed roller.
- the first encoder detects a rotation amount of the first drive source.
- the first drive controller controls a speed or a position of the first drive source based on the rotation amount detected by the first encoder.
- the separation roller nips a sheet with the feed roller.
- the second drive source rotates the separation roller.
- the second encoder detects a rotation amount of the second drive source.
- the second drive controller performs torque control of the second drive source. The torque control performed by the second drive controller rotates the separation roller with rotation of the feed roller in a sheet conveyance direction when a force having a predetermined value or more is applied to the separation roller from the feed roller in direct contact with the separation roller or nipping a sheet with the separation roller.
- the torque control performed by the second drive controller rotates the separation roller in a direction opposite the sheet conveyance direction when a force having a value less than the predetermined value is applied from the feed roller to the separation roller. Such torque control returns an excess sheet to the sheet stacker if sheets are multi-fed.
- the separation pressure provider provides a pressure by which the separation roller is pressed against the feed roller.
- the torque estimation device estimates a torque of the second drive source with an applied voltage to the second drive source from the second drive controller after calculating a turning angle speed from the rotation amount of the second drive source detected by the second encoder based on a relational expression between a motor rotation speed and an applied voltage that are measured beforehand for the second drive source and a torque of the second drive source.
- FIG. 1 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to an embodiment of the present disclosure
- FIG. 2 is a block diagram illustrating a control system of a separation motor of the sheet conveyance device
- FIG. 3 is a diagram illustrating an example of a reaction force estimation observer
- FIG. 4 is a diagram illustrating an example of a configuration in which a multi-sheet feed detector that detects multi-sheet feeding is disposed in the sheet conveyance device;
- FIG. 5 is a diagram illustrating times at which the multi-sheet feed detector illustrated in FIG. 4 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in rotation speed of a separation motor;
- FIG. 6 is a schematic diagram illustrating one example of the sheet conveyance device in which a target torque of the separation motor is increased if the multi-sheet feed detector illustrated in FIG. 4 monitors a torque estimation value of the separation motor and determines that sheet separation is to be started as sheets are multi-fed;
- FIG. 7 is a diagram illustrating times at which the sheet conveyance device illustrated in FIG. 6 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in torque estimation value;
- FIGS. 8A and 8B are diagrams illustrating leading end positions of a first sheet and a multi-fed sheet if a sheet feed motor is not stopped and is stopped, respectively, according to one embodiment of the present disclosure
- FIG. 9 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to one embodiment of the present disclosure.
- FIG. 10 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to the embodiment (if a single controller is disposed);
- FIG. 11 is a sectional view illustrating a schematic configuration of the sheet conveyance device according to the embodiment (if the single controller is disposed);
- FIG. 12 is a diagram illustrating an example of a sheet type input device according to the embodiment.
- FIG. 13 is a sectional view illustrating an image forming apparatus according to one embodiment of the present disclosure.
- the present disclosure relates to a sheet supplying device (also referred to as a conveyance device) that separates and feeds sheets one by one from a tray on which the sheets (recording media such as paper) are stacked, and to an image forming apparatus including the sheet supplying device.
- the image forming apparatus is, for example, a copier, a printer, a facsimile machine, a multifunction peripheral having two or more copying, printing, and facsimile functions, and an offset printing machine.
- the sheet supplying device as a conveyance device includes a feed roller that is rotated to feed a sheet in a sheet conveyance direction, and a separation roller that nips the sheet with a feed roller against which the separation roller is pressed.
- the separation roller is driven by torque control.
- the separation roller is rotated in the sheet conveyance direction with rotation of the feed roller when a force having a predetermined amount or more is applied from the feed roller in direct contact with the separation roller or nipping the sheet with the separation roller.
- the separation roller is rotated in a direction opposite the sheet conveyance direction when a force having a predetermined amount or less is applied.
- the sheet supplying device and the image forming apparatus have the following characteristics. Based on a relational expression between a motor rotation speed and an applied voltage that are measured beforehand for a direct current (DC) motor as a separation motor and a torque of the DC motor, a torque is estimated from a detection result of the motor rotation speed and an output (a motor drive voltage) of a controller, and a determination is made on control based on the estimated torque to set a target value. Thus, torque control is performed without an electric current detector (a sensor).
- DC direct current
- FIG. 1 is a sectional view illustrating a schematic configuration of a sheet conveyance device 1201 as a conveyance device according to an embodiment.
- the sheet conveyance device 1201 includes a sheet feed roller C 2 as a feed roller, a separation roller C 1 , a sheet feed motor M 2 , and a separation motor M 1 that form a sheet conveyance mechanism.
- the sheet conveyance mechanism causes a sheet to be nipped between the sheet feed roller C 2 and the separation roller C 1 , and rotates the sheet feed roller C 2 to convey the sheet.
- the sheet conveyance device 1201 also includes a sheet stacking tray T on which sheets are stacked, a sheet raising plate that raises the sheet stacked on the sheet stacking tray T toward a pickup roller C 3 , a timing belt that transmits rotation of the sheet feed motor M 2 to the pickup roller C 3 , and the separation motor M 1 .
- the separation motor M 1 rotates the separation roller C 1 in a direction opposite a sheet conveyance direction D 1 .
- the sheet conveyance device 1201 includes a sensor that detects a sheet conveyed in a sheet conveyance direction D 1 , and a separation roller urging member 103 that urges the separation roller C 1 toward the sheet feed roller C 2 .
- the sensor is disposed directly below a shaft of the sheet feed roller C 2 or slightly downstream from the sheet feed roller C 2 in the sheet conveyance direction.
- the sheet conveyance device 1201 raises the sheet raising plate disposed inside the sheet stacking tray T to raise the sheets stacked on the sheet stacking tray T, so that the top sheet of the stack is pressed against the pickup roller C 3 .
- the raising of the sheet raising plate stops when the top sheet is pressed against the pickup roller C 3 with a pressure within a predetermined range.
- a sensor is disposed to detect that the top sheet is pressed against the pickup roller C 3 .
- the sheet conveyance device 1201 rotates the pickup roller C 3 in the sheet conveyance direction D 1 with the top sheet pressed against the pickup roller C 3 , a sheet is fed from the sheet stacking tray T.
- Rotation of the sheet feed motor M 2 as a drive source of the sheet feed roller C 2 is transmitted to the pickup roller C 3 via the timing belt, so that the pickup roller C 3 is rotated.
- the sheet fed from the sheet stacking tray T enters a portion (a nip portion) in which the sheet feed roller C 2 and the separation roller C 1 are pressed against each other.
- the sheet feed roller C 2 is rotated by the sheet feed motor M 2 such that the sheet is fed in the sheet conveyance direction D 1 .
- the sheet feed roller C 2 and the separation roller C 1 pressed against each other nip the sheet.
- a controller 102 controls a position or a speed of the sheet feed motor M 2 .
- the separation roller C 1 is driven by the separation motor M 1 via a predetermined driving force transmitter.
- a controller 101 controls a return force to control the separation roller C 1 via the separation motor M 1 for the separation roller C 1 without arraignment of a torque limiter as a predetermined driving force transmitter on a separation roller shaft.
- the separation motor M 1 rotates the separation roller C 1 in a direction opposite the sheet conveyance direction.
- the controller 101 controls the separation motor M 1 by using torque to rotate the separation roller C 1 in the sheet conveyance direction (a direction D 2 illustrated in FIG. 1 while applying a return force).
- the controller 101 controls the separation motor M 1 by using torque to stop or rotate the separation roller C 1 in an opposite direction (a direction D 3 illustrated in FIG. 1 ).
- the sheet conveyance mechanism feeds the sheets one by one.
- a drive source for the separation roller C 1 can be shared with the sheet feed motor M 2 , instead of arranging a drive source as the separation motor M 1 dedicated to the separation roller C 1 .
- the present embodiment has been described using one example (a spring) of the separation roller urging member 103 as a device that gives a pressure (a separation pressure) by which the separation roller C 1 as a reverse roller is pressed to the sheet feed roller C 2 .
- a mechanism that causes a gear attached to a separation roller shaft to sprig up by a gear connected to a drive source may be used, or a configuration similar to a configuration of a conventional sheet conveyance device may be employed, instead of the spring.
- the sheet conveyance device 1201 includes the sheet stacking tray T, the pickup roller C 3 , the sheet feed roller C 2 , the sheet feed motor M 2 , a first encoder, the controller 102 , the separation roller C 1 , the separation motor M 1 , a second encoder, the controller 101 , and the separation roller urging member 103 .
- the sheet stacking tray T serves as a sheet stacker on which sheets are stacked.
- the pickup roller C 3 contacts the top sheet of the stack on the sheet stacker, and is rotated in the sheet conveyance direction D 1 .
- the sheet feed roller C 2 as a feed roller is rotated to feed a sheet in the sheet conveyance direction D 1 .
- the sheet feed motor M 2 as a first drive source rotates the pickup roller C 3 and the sheet feed roller C 2 , and the first encoder detects a rotation amount of the sheet feed motor M 2 .
- the controller 102 as a first drive controller controls a speed or a position of the first drive source based on the rotation amount detected by the first encoder.
- the separation roller C 1 nips a sheet with the sheet feed roller C 2 against which the separation roller C 1 is pressed.
- the separation motor M 1 as a second drive source rotates the separation roller C 1 , and the second encoder detects a rotation amount of the separation motor M 1 .
- the controller 101 as a second drive controller performs torque control of the separation motor M 1 , and the separation roller urging member 103 as a separation pressure provider provides a pressure (a separation pressure) by which the separation roller C 1 is pressed against the sheet feed roller C 2 .
- the torque control performed by the second drive controller controls a torque (a return force) such that the separation roller C 1 is rotated with rotation of the sheet feed roller C 2 in the direction D 2 which is the same direction as the sheet conveyance direction D 1 when a force having a predetermined value or more is applied from the sheet feed roller C 2 in direct contact with the separation roller C 1 or nipping a sheet with the separation roller C 1 .
- the torque control performed by the second drive controller controls a torque (a return force) such that the separation roller C 1 is rotated in a direction D 3 opposite the sheet conveyance direction D 1 when a force having a value less than the predetermined value is applied.
- a torque a return force
- the separation motor M 1 as the second drive source is a DC motor.
- a reaction force estimation observer 201 (described below) as a torque estimation device calculates a turning angle speed from a rotation amount of the separation motor M 1 detected by the second encoder, and then estimates a torque of the DC motor with an applied voltage to the DC motor from the controller 101 as the second drive controller.
- a reaction force estimation observer 201 as a torque estimation device calculates a turning angle speed from a rotation amount of the separation motor M 1 detected by the second encoder, and then estimates a torque of the DC motor with an applied voltage to the DC motor from the controller 101 as the second drive controller.
- FIG. 2 is a block diagram illustrating a control system of the separation motor M 1 of the sheet conveyance device 1201 .
- the sheet conveyance device 1201 does not use an electric current detector (a sensor) to detect an electric current of a motor.
- the sheet conveyance device 1201 inputs an output (a motor applied voltage) of the controller 101 and a motor shaft rotation speed measured by a sensor to the reaction force estimation observer 201 to calculate an estimation value of a return force to a sheet as a reaction force estimation value, and performs feedback control.
- a plant C 10 includes the separation motor M 1 and a drive module such as the separation roller C 1 .
- An example of the reaction force estimation observer 201 may have a known configuration as illustrated in FIG. 3 . In the example illustrated in FIG. 3 , a motor applied voltage and a motor shaft rotation speed are input to output an estimation value of a reaction force (torque).
- the sheet conveyance device 1201 can include a multi-sheet feed detector 401 that detects multi-sheet feeding.
- the multi-sheet feed detector 401 monitors a rotation speed of the separation motor M 1 to determine whether sheet separation is to be started as sheets are multi-fed. If the multi-sheet feed detector 401 determines that sheet separation is to be started, a target torque of the separation motor M 1 is increased. In FIG. 4 , the multi-sheet feed detector 401 receives a rotation speed from the separation motor M 1 . If the rotation speed is a predetermined threshold value or greater and remains unchanged for a certain time period, the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, and instructs the controller 101 to change a target torque.
- the sheet conveyance device 1201 illustrated FIG. 1 includes the multi-sheet feed detector 401 which monitors a rotation amount (a rotation speed) of the separation motor M 1 as the second drive source during sheet feeding. If the rotation speed falls below a predetermined value, the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed. If sheet separation is to be started as sheets are multi-fed, the multi-sheet feed detector 401 controls the controller 101 as the second drive controller to increase a target torque for torque control. Such control enables multi-sheet feeding to be detected without arrangement of a dedicated multi-sheet feed detection sensor. Moreover, since a return force is increased when only sheets are multi-fed, unnecessary return force is not applied during single-sheet feeding in which sheets are not multi-fed. Thus, a rubbing amount of a separation roller against a sheet can be reduced, and the lifetime of a component of the separation roller can be extended.
- a rotation amount a rotation speed
- FIG. 5 is a diagram illustrating times at which the multi-sheet feed detector illustrated in FIG. 4 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in rotation speed of the separation motor.
- a rotation speed of the separation motor M 1 exceeds a threshold value V 1 , and the multi-sheet feed detector 401 starts monitoring the rotation speed of the separation motor M 1 at a time T 0 .
- the rotation speed of the separation motor M 1 may remain constant for a certain time period.
- the multi-sheet feed detector 401 determines that sheets are multi-fed and instructs the controller 101 to change a target torque. Accordingly, the controller 101 changes the target torque such that the separation motor M 1 is rotated in reverse for a certain time period.
- the multi-sheet feed detector 401 increases the rotation speed of the separation motor M 1 as similar to the situation prior to the time T 1 .
- the rotation speed of the separation motor M 1 exceeds a threshold value V 2 that is used for determination of completion of the sheet separation
- the multi-sheet feed detector 401 determines that the sheet separation is completed at a time T 2 at which the rotation speed exceeds the threshold value V 2 , and conveyance of the sheet continues.
- a threshold value (V 1 ) to be used for determination of the start of sheet separation as sheets are multi-fed and a threshold value (V 2 ) to be used for determination of completion of the sheet separation can be same value or different values.
- the separation motor M 1 intends to rotate the separation roller C 1 in a direction opposite the sheet conveyance direction.
- the separation roller C 1 is decelerated and rotated in reverse.
- the separation roller C 1 is rotated in the sheet conveyance direction.
- FIG. 6 is a schematic diagram illustrating one example of the sheet conveyance device 1201 in which the multi-sheet feed detector 401 illustrated in FIG. 4 monitors a torque estimation value of the separation motor M 1 to increase a target torque of the separation motor M 1 if the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed.
- the multi-sheet feed detector 401 receives a torque estimation value of the separation motor M 1 from the controller 101 . If the torque estimation value is a predetermined threshold value or greater and remains unchanged for a certain time period, the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, and instructs the controller 101 to change a target torque.
- the sheet conveyance device 1201 illustrated FIG. 6 includes the multi-sheet feed detector 401 .
- the multi-sheet feed detector 401 monitors torque (an estimation value provided by the reaction force estimation observer 201 as a torque estimator) of the separation motor M 1 as the second drive source during sheet feeding.
- the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, if the toque estimation value falls below a predetermined value. If the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, a target torque for torque control to be performed by the controller 101 as the second drive controller is increased.
- multi-sheet feeding can be detected by a method different from the method described with reference to FIG. 4 without a dedicated multi-sheet feed detection sensor.
- a return force is increased when only sheets are multi-fed, unnecessary return force is not applied during single-sheet feeding in which sheets are not multi-fed.
- a rubbing amount of a separation roller against a sheet can be reduced, and the lifetime of a component of the separation roller can be extended.
- FIG. 7 is a diagram illustrating times at which the sheet conveyance device 1201 illustrated in FIG. 6 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in torque estimation value.
- a torque estimation value of the separation motor M 1 exceeds the threshold value V 1 , and the multi-sheet feed detector 401 starts monitoring the torque estimation value of the separation motor M 1 at a time T 0 .
- the torque estimation value of the separation motor M 1 may remain constant for a certain time period without increasing.
- the multi-sheet feed detector 401 determines that sheets are multi-fed at a time T 3 at which the certain time has elapsed, and instructs the controller 101 to change a target torque. Accordingly, the controller 101 changes the target torque such that the separation motor M 1 is rotated in reverse for a certain time period. Subsequently, the multi-sheet feed detector 401 increases the torque estimation value of the separation motor M 1 , as similar to the situation prior to the time T 3 .
- the multi-sheet feed detector 401 determines that the sheet separation is completed at a time T 4 at which the torque estimation value exceeds the threshold value V 2 , and conveyance of the sheet continues. If a torque estimation value of the separation motor M 1 is constant without increasing, the multi-sheet feed detector 401 can make a determination based on the presume that a slip of a lower sheet of multi-fed sheets with respect to an upper sheet by a return force from the separation roller C 1 reduces a reaction force estimated by the reaction force estimation observer 201 .
- a time at which such a determination is made can be determined as a time T 3 at which sheet separation is started as sheets are multi-fed.
- a threshold value (V 1 ) to be used for determination of the start of sheet separation as sheets are multi-fed and a threshold value (V 2 ) for determination of completion of the sheet separation can be same value or different values.
- the multi-sheet feed detector 401 can perform control such that a target torque remains large until a sheet being conveyed passes. When such control can return the multi-fed sheet to the tray side, the separation roller C 1 is rotated with a sheet in a sheet conveyance direction D 1 . In the sheet conveyance device 1201 illustrated in FIGS. 4 and 6 , if a rotation speed or a torque estimation value exceeds a predetermined value again, a target torque level is controlled to return to an initial value.
- a target torque level is controlled not to return to an initial value.
- a return operation can be performed promptly, even if sheets are multi-fed again.
- the multi-sheet feed detector 401 after determining that sheet separation is to be started as sheets are multi-fed, the multi-sheet feed detector 401 continue to monitor a rotation amount (a rotation speed) of the separation motor M 1 as the second drive source, or torque (an estimation amount provided by the torque estimation device) of the separation motor M 1 as the second drive source. If the rotation amount (the rotation speed) of the second drive source or the torque (the estimation amount provided by the torque estimation device) of the second drive source exceeds a predetermined value, the multi-sheet feed detector 401 determines that the sheet separation is completed.
- the controller 102 as a first drive controller stops the driving of the sheet feed motor M 2 as the first drive source if the multi-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed.
- the controller 102 resumes driving of the first drive source if the multi-sheet feed detector 401 determines that the sheet separation is completed.
- the controller 102 as the first drive controller can reduce driving of the sheet feed motor M 2 as the first drive source to a predetermined speed if the multi-sheet feed detector 401 determines that separation of sheets has been started as the sheets are multi-fed.
- the controller 102 can control a speed of the first drive source to return to a normal speed if the multi-sheet feed detector 401 determines that the sheet separation is completed.
- FIG. 8A is diagram illustrating leading end positions 801 and 802 of a first sheet and a multi-fed sheet if the sheet feed motor M 2 is not stopped
- FIG. 8B is a diagram illustrating leading end positions 803 and 804 of a first sheet and a multi-fed sheet if the sheet feed motor M 2 is stopped according to one embodiment of the present disclosure.
- the controller 101 stops the sheet feed motor M 2 if multi-sheet feeding is detected from a position (P 2 ) of a sheet feed separation portion as a nip portion formed by the separation roller C 1 and the sheet feed roller C 2 to a position (P 1 ) of a conveyance roller disposed downstream in a conveyance direction.
- P 2 a position of a sheet feed separation portion as a nip portion formed by the separation roller C 1 and the sheet feed roller C 2
- the leading end position 801 of the first sheet moves with time to the position (P 1 ) of the conveyance roller disposed downstream in the conveyance direction.
- the leading end position 802 of a lower sheet that is prevented by the separation roller C 1 from being multi-fed after the leading end position 802 intends to move to the position (P 1 ) of the conveyance roller disposed downstream in the conveyance direction with the first sheet, the leading end position 802 remains unchanged even after a certain time period has elapsed.
- the leading end position 804 of a lower sheet does not intend to move to the position (P 1 ) of the conveyance roller disposed downstream in the conveyance direction, and is not changed even after the certain time period has elapsed. That is, the sheet feed motor M 2 is stopped, so that a multi-fed sheet is prevented from moving excessively, and a possibility that the multi-fed sheet may reach a downstream roller pair (a conveyance roller pair) can be reduced even more.
- FIG. 9 is a sectional view illustrating a schematic configuration of the sheet conveyance device 1201 according to one embodiment of the present disclosure.
- the sheet conveyance device 1201 includes a conveyance-roller-pair sheet nipping determiner 903 in addition to the configuration illustrated in FIG. 4 .
- the conveyance-roller-pair sheet nipping determiner 903 determines whether a conveyance roller pair has nipped a sheet.
- the sheet conveyance device 1201 includes a conveyance roller pair (a conveyance roller R 1 and a counter roller R 2 ), a conveyance motor M 3 as a third drive source, a third encoder, a controller 902 as a third drive controller, and the conveyance-roller-pair sheet nipping determiner 903 that are disposed downstream of the sheet conveyance device 1201 in the sheet conveyance direction D 1 illustrated in FIG. 1 .
- the conveyance roller pair is pressed against each other to nip a sheet fed from the sheet conveyance device 1201 .
- the conveyance motor M 3 rotates the conveyance roller pair (or the conveyance roller R 1 ).
- the third encoder detects a rotation amount of the conveyance motor M 3 .
- the controller 902 controls a position or a speed of the conveyance motor M 3 .
- the conveyance-roller-pair sheet nipping determiner 903 uses a sheet detector 901 such as a sensor to determine whether the conveyance roller pair has nipped a sheet.
- the sheet detector 901 detects the presence or absence of a sheet in a position of the conveyance roller pair or a position slightly downstream of the conveyance roller pair. In the sheet conveyance device 1201 illustrated in FIG.
- the controller 902 stops the driving of the sheet feed motor M 2 . If the multi-sheet feed detector 401 determines that the sheet separation is completed, the controller 902 resumes the driving of the conveyance motor M 3 .
- Such control enables effects similar to FIGS. 4 and 6 to be obtained even when a second sheet or subsequent sheets enter a portion in which the sheet feed roller C 2 and the separation roller C 1 forming a sheet feed separation portion are in contact with each other after a first sheet reaches the conveyance roller pair.
- the controller 902 reduces the driving of the conveyance motor M 3 to a predetermined speed. If the multi-sheet feed detector 401 determines that the sheet separation is completed, the controller 902 returns the speed of the conveyance motor M 3 to a normal speed. Such control enables effects similar to FIGS. 4 and 6 to be obtained, even if a second sheet or subsequent sheets enter a portion in which the sheet feed roller C 2 and the separation roller C 1 forming a sheet feed separation portion are in contact with each other after a first sheet reaches the conveyance roller pair.
- the controller 102 as the first drive controller can stop the driving of the sheet feed motor M 2 as the first drive source.
- a function of the controller 102 can be included in the controller 101 , so that the sheet conveyance device 1201 can include a single controller. With such arrangement, the sheet conveyance device 1201 can be made more compact
- FIG. 12 is a diagram illustrating an example of a sheet type input portion 1202 according to the present embodiment.
- the sheet conveyance device 1201 includes a sheet stacking tray 1203 , a sheet ejection port tray 1204 to which a sheet is ejected, and a sheet type input device including the sheet type input portion 1202 .
- the sheet type input portion 1202 is used to input (select) a sheet type.
- the sheet conveyance device 1201 which has been described with reference to the drawings can include the sheet type input device including the sheet type input portion 1202 to which a sheet type can be input by a user. At least one of a predetermined value of rotation speed or torque estimation value, a target torque, and a value of target torque at the time of multi-sheet feeding can be changed depending on the sheet type input from the sheet type input device.
- a suitable return force to be set according to a sheet type (characteristic), so that multi-sheet feed prevention performance (separability) can be enhanced, and a rubbing amount of a separation roller against a sheet can be reduced.
- FIG. 13 is a sectional view illustrating an image forming apparatus 1000 according to one embodiment.
- the image forming apparatus 1000 illustrated in FIG. 13 is an electrophotographic tandem-type indirect-transfer color copier (hereinafter simply referred to as a copier), and a schematic configuration illustrated in FIG. 13 is one example of an internal mechanical part of the copier.
- the image forming apparatus 1000 includes a copier body 100 as an image forming apparatus body, a sheet conveyance device 200 on which the copier body 100 is placed, a scanner 300 that is attached on the copier body 100 , and an automatic document feeder (ADF) 400 that is attached on the scanner 300 .
- ADF automatic document feeder
- an intermediate transfer body 10 of an endless belt is stretched by a drive roller 14 and two driven rollers 15 and 16 , and is rotatable clockwise in FIG. 13 .
- the intermediate transfer body 10 may be stretched by four or more rollers including a roller that adjusts deviation of the intermediate transfer body 10 .
- the intermediate transfer body 10 is stretched in a substantially horizontal manner.
- the intermediate transfer body 10 may be diagonally stretched, instead of being horizontally stretched.
- the copier body 100 also includes a belt cleaning device 17 on the left side of the driven roller 15 which is one of the driven rollers.
- the belt cleaning device 17 removes residual toner remaining on the intermediate transfer body 10 subsequent to transfer of an image.
- a tandem image formation device 20 is disposed on the intermediate transfer body 10 which is horizontally stretched between the drive roller 14 and the driven roller 15 .
- the tandem image formation device 20 includes four single-color image formation devices 18 Y, 18 C, 18 M, and 18 K for yellow, cyan, magenta, and black that are aligned along a direction of movement of the intermediate transfer body 10 .
- an exposure device 21 is disposed above the tandem image formation device 20 .
- a secondary transfer device 22 is disposed below an area in which the intermediate transfer body 10 is stretched.
- the secondary transfer device 22 includes a secondary transfer belt 24 of an endless belt that is stretched between two rollers 23 and is pressed against the driven roller 16 to transfer an image on the intermediate transfer body 10 to a recording medium.
- a fixing device 25 that fixes the transferred image on the recording medium is disposed beside the secondary transfer device 22 .
- the fixing device 25 is configured to press a pressure roller 27 against a fixing belt 26 of an endless belt.
- one portion of the fixing device 25 is (the entire portion of the fixing device 25 can be) arranged below the area in which intermediate transfer body 10 is stretched.
- the secondary transfer device 22 also has a recording medium conveyance function of conveying the recording medium with the transferred image to the fixing device 25 .
- a non-contact charger may be disposed as the secondary transfer device 22 . In such a case, however, the non-contact charger as the secondary transfer device 22 has a difficulty in having such a recording medium conveyance function.
- a recording medium reverse device 28 is disposed below the secondary transfer device 22 and the fixing device 25 .
- the recording medium reverse device 28 is disposed parallel to a direction in which the intermediate transfer body 10 is stretched.
- the recording medium reverse device 28 reverses a recording medium to form images on two sides of the recording medium.
- a document is set on a document tray 30 of the ADF 400 or the ADF 400 is opened to directly set a document on an exposure glass 32 , and the ADF 400 is closed to hold the document with the ADF 400 . Subsequently, a start switch is pressed. If the document is set on the ADF 400 , the document is conveyed and moved to the exposure glass 32 , and then the scanner 300 is driven to read the contents of the document. If the document is directly set on the exposure glass 32 , the content of the document is read by the scanner 300 without conveyance of the document.
- the drive roller 14 is rotated by a drive motor and the driven rollers 15 and 16 are rotated by rotation of the drive roller 14 to rotate the intermediate transfer body 10 .
- image bearers 40 Y, 40 C, 40 M and 40 K are respectively rotated to form single color images of respective colors (yellow, cyan, magenta, and black) on the image bearers 40 Y, 40 C, 40 M and 40 K.
- the single-color images are primarily transferred and sequentially overlapped with movement of the intermediate transfer body 10 , so that combined color images are formed on the intermediate transfer body 10 .
- one of pickup rollers 42 of the sheet conveyance device 200 is selected and rotated at an appropriate time after the start switch is pressed. Then, recording media are fed from one of a plurality of sheet stacking trays 44 in a sheet bank 43 . The recording media are separated one by one by a separation roller 45 and enter separately a sheet conveyance path 46 . The recording medium is then conveyed by a conveyance roller 47 and is guided to a sheet feed path 48 inside the copier body 100 . When the recording medium contacts a registration roller 49 , the conveyance of the recording medium stops. If recording media are manually fed, the recording media set on a manual feed tray 51 that is opened with rotation of a sheet feed roller 50 are fed. Then, the recording media are separated one by one by a separation roller 52 and enter separately a manual feed sheet conveyance path 53 . As similar to the above, the recording medium contacts the registration roller 49 , and the conveyance of the recording medium stops.
- the registration roller 49 is rotated to time with the combined color images on the intermediate transfer body 10 , and the recording medium is fed between the intermediate transfer body 10 and the secondary transfer device 22 .
- the secondary transfer device 22 secondarily transfers the combined color images on the intermediate transfer body 10 to the recording medium in a collective manner to form a color image on the recording medium.
- the recording medium with the transferred image is conveyed by the secondary transfer device 22 to the fixing device 25 .
- a conveyance direction of the recording medium is switched by a switching pawl 55 and the recording medium is ejected by an ejection roller 56 .
- the ejected recording medium is stacked on an ejection tray 57 . If images are to be formed on two sides of the recording medium, a conveyance direction of the recording medium is switched by the switching pawl 55 and the recording medium enters the recording medium reverse device 28 .
- the recording medium is reversed in the recording medium reverse device 28 .
- the reversed recording medium is guided to a transfer position again, and an image is formed on the back surface of the recording medium. Subsequently, the recording medium is ejected by the ejection roller 56 to the ejection tray 57 .
- the belt cleaning device 17 removes a residual toner remaining on the intermediate transfer body 10 after the image is transferred, and the intermediate transfer body 10 becomes ready again for image formation to be performed by the tandem image formation device 20 .
- a device that supplies sheet-type recording media such as paper is disposed.
- the sheet conveyance device 1201 according to the embodiment can be applied to such a device for supplying recording media.
- the application of the sheet conveyance device 1201 can provide an image forming apparatus that reduces a degree of degradation of a separation roller at lower cost while maintaining or enhancing multi-sheet feed prevention performance (separability).
- Processing circuitry includes a programmed processor, as a processor includes circuitry.
- a processing circuit also includes devices such as an application specific integrated circuit (ASIC), digital signal processor (DSP), field programmable gate array (FPGA), and conventional circuit components arranged to perform the recited functions.
- ASIC application specific integrated circuit
- DSP digital signal processor
- FPGA field programmable gate array
- Program codes executed by the image processing apparatus to achieve the functions of the described embodiments may be provided in files in an installable format or an executable format that are recorded on computer-readable recording media such as a CD-ROM, a flexible disk (FD), a CD-R, and a digital versatile disk (DVD).
- the program codes executed by the image processing apparatus may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network, or be provided or distributed via a network such as the Internet.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sheets, Magazines, And Separation Thereof (AREA)
- Paper Feeding For Electrophotography (AREA)
- Controlling Sheets Or Webs (AREA)
Abstract
Description
- This patent application is based on and claims priority pursuant to 35 U.S.C. § 119 to Japanese Patent Application No. 2020-051103, filed on Mar. 23, 2020, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
- Exemplary aspects of the present disclosure relate to a conveyance device and an image forming apparatus.
- Cut-sheet feeding devices including a multi-sheet feed prevention mechanism and capable of not only prolonging the lifespan of a feed roller but also reducing stress to be applied to a cut sheet are known. Such a cut-sheet feeding device includes a device for detecting a friction coefficient between sheets, a device for detecting the frequency of feeding of a cut sheet with feeding of another sheet, a device for detecting a cut-sheet conveyance speed in the course of sheet feeding, and a controller. The controller changes and controls sheet handling capability in the multi-sheet feed prevention system based on a combination of detection results provided by the three detection devices.
- In addition, sheet feeding devices that separate and feed sheets one by one are known. Such a sheet feeding device is provided to reliably prevent multi-sheet feeding and non-feeding. In addition, the sheet feeding device is provided to determine multi-sheet feeding or a thick sheet. Such a sheet feeding device includes a separator, a thickness detector, and a controller. The separator includes a feed roller that conveys a sheet in a conveyance direction and a reverse roller disposed opposite the feed roller to separate sheets conveyed between the feed roller and the reverse roller one by one. The thickness detector detects a thickness of the sheets to be separated by the separator. The controller controls a push-back force of the reverse roller based on detection information about the sheet thickness detected by the thickness detector.
- In at least one embodiment of this disclosure, there is described an improved conveyance device that includes a sheet stacker, a pickup roller, a feed roller, a first drive source, a first encoder, a first drive controller, a separation roller, a second drive source, a second encoder, a second drive controller, a separation pressure provider, and a torque estimation device. The sheet stacker is a stacker on which sheets are stacked. The pickup roller contacts a top sheet of the sheets stacked on the sheet stacker, and rotates in a sheet conveyance direction. The feed roller rotates to feed the sheet in the sheet conveyance direction. The first drive source rotates the pickup roller and the feed roller. The first encoder detects a rotation amount of the first drive source. The first drive controller controls a speed or a position of the first drive source based on the rotation amount detected by the first encoder. The separation roller nips a sheet with the feed roller. The second drive source rotates the separation roller. The second encoder detects a rotation amount of the second drive source. The second drive controller performs torque control of the second drive source. The torque control performed by the second drive controller rotates the separation roller with rotation of the feed roller in a sheet conveyance direction when a force having a predetermined value or more is applied to the separation roller from the feed roller in direct contact with the separation roller or nipping a sheet with the separation roller. The torque control performed by the second drive controller rotates the separation roller in a direction opposite the sheet conveyance direction when a force having a value less than the predetermined value is applied from the feed roller to the separation roller. Such torque control returns an excess sheet to the sheet stacker if sheets are multi-fed. The separation pressure provider provides a pressure by which the separation roller is pressed against the feed roller. The torque estimation device estimates a torque of the second drive source with an applied voltage to the second drive source from the second drive controller after calculating a turning angle speed from the rotation amount of the second drive source detected by the second encoder based on a relational expression between a motor rotation speed and an applied voltage that are measured beforehand for the second drive source and a torque of the second drive source.
- Further described is an improved image forming apparatus that includes the conveyance device described above.
- The aforementioned and other aspects, features, and advantages of the present disclosure are better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
-
FIG. 1 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to an embodiment of the present disclosure; -
FIG. 2 is a block diagram illustrating a control system of a separation motor of the sheet conveyance device; -
FIG. 3 is a diagram illustrating an example of a reaction force estimation observer; -
FIG. 4 is a diagram illustrating an example of a configuration in which a multi-sheet feed detector that detects multi-sheet feeding is disposed in the sheet conveyance device; -
FIG. 5 is a diagram illustrating times at which the multi-sheet feed detector illustrated inFIG. 4 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in rotation speed of a separation motor; -
FIG. 6 is a schematic diagram illustrating one example of the sheet conveyance device in which a target torque of the separation motor is increased if the multi-sheet feed detector illustrated inFIG. 4 monitors a torque estimation value of the separation motor and determines that sheet separation is to be started as sheets are multi-fed; -
FIG. 7 is a diagram illustrating times at which the sheet conveyance device illustrated inFIG. 6 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in torque estimation value; -
FIGS. 8A and 8B are diagrams illustrating leading end positions of a first sheet and a multi-fed sheet if a sheet feed motor is not stopped and is stopped, respectively, according to one embodiment of the present disclosure; -
FIG. 9 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to one embodiment of the present disclosure; -
FIG. 10 is a sectional view illustrating a schematic configuration of a sheet conveyance device according to the embodiment (if a single controller is disposed); -
FIG. 11 is a sectional view illustrating a schematic configuration of the sheet conveyance device according to the embodiment (if the single controller is disposed); -
FIG. 12 is a diagram illustrating an example of a sheet type input device according to the embodiment; and -
FIG. 13 is a sectional view illustrating an image forming apparatus according to one embodiment of the present disclosure. - The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted.
- In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have the same function, operate in a similar manner and achieve similar results.
- Referring now to the drawings, embodiments of the present disclosure are described below. In the drawings for explaining the following embodiments, the same reference codes are allocated to elements (members or components) having the same function or shape and redundant descriptions thereof are omitted below.
- Hereinafter, exemplary embodiments of the present disclosure are described. The present disclosure relates to a sheet supplying device (also referred to as a conveyance device) that separates and feeds sheets one by one from a tray on which the sheets (recording media such as paper) are stacked, and to an image forming apparatus including the sheet supplying device. The image forming apparatus is, for example, a copier, a printer, a facsimile machine, a multifunction peripheral having two or more copying, printing, and facsimile functions, and an offset printing machine. Particularly, the sheet supplying device as a conveyance device includes a feed roller that is rotated to feed a sheet in a sheet conveyance direction, and a separation roller that nips the sheet with a feed roller against which the separation roller is pressed. The separation roller is driven by torque control. The separation roller is rotated in the sheet conveyance direction with rotation of the feed roller when a force having a predetermined amount or more is applied from the feed roller in direct contact with the separation roller or nipping the sheet with the separation roller. The separation roller is rotated in a direction opposite the sheet conveyance direction when a force having a predetermined amount or less is applied. Accordingly, if a plurality of sheets is fed from the tray with the sheets overlapped, a sheet that is excessively fed is returned to the sheet stacker, so that the sheets are separated and fed one by one. The sheet supplying device and the image forming apparatus have the following characteristics. Based on a relational expression between a motor rotation speed and an applied voltage that are measured beforehand for a direct current (DC) motor as a separation motor and a torque of the DC motor, a torque is estimated from a detection result of the motor rotation speed and an output (a motor drive voltage) of a controller, and a determination is made on control based on the estimated torque to set a target value. Thus, torque control is performed without an electric current detector (a sensor). In addition, not only the separation motor is controlled, but also control of a feed motor is adjusted depending on the presence or absence of multi-feed sheeting, so that multi-sheet feeding can be prevented more easily. Hence, enhancement of sheet separability of the sheet supplying device and reduction of characteristic degradation of a component (reverse-roller abrasion) can be achieved at lower cost. Such characteristics of the present disclosure are hereinafter described in detail with reference to the drawings.
-
FIG. 1 is a sectional view illustrating a schematic configuration of asheet conveyance device 1201 as a conveyance device according to an embodiment. Thesheet conveyance device 1201 includes a sheet feed roller C2 as a feed roller, a separation roller C1, a sheet feed motor M2, and a separation motor M1 that form a sheet conveyance mechanism. The sheet conveyance mechanism causes a sheet to be nipped between the sheet feed roller C2 and the separation roller C1, and rotates the sheet feed roller C2 to convey the sheet. Thesheet conveyance device 1201 also includes a sheet stacking tray T on which sheets are stacked, a sheet raising plate that raises the sheet stacked on the sheet stacking tray T toward a pickup roller C3, a timing belt that transmits rotation of the sheet feed motor M2 to the pickup roller C3, and the separation motor M1. The separation motor M1 rotates the separation roller C1 in a direction opposite a sheet conveyance direction D1. In addition, thesheet conveyance device 1201 includes a sensor that detects a sheet conveyed in a sheet conveyance direction D1, and a separationroller urging member 103 that urges the separation roller C1 toward the sheet feed roller C2. The sensor is disposed directly below a shaft of the sheet feed roller C2 or slightly downstream from the sheet feed roller C2 in the sheet conveyance direction. - With such a configuration, when a sheet is to be supplied, the
sheet conveyance device 1201 raises the sheet raising plate disposed inside the sheet stacking tray T to raise the sheets stacked on the sheet stacking tray T, so that the top sheet of the stack is pressed against the pickup roller C3. Herein, the raising of the sheet raising plate stops when the top sheet is pressed against the pickup roller C3 with a pressure within a predetermined range. A sensor is disposed to detect that the top sheet is pressed against the pickup roller C3. When a sheet is not to be supplied, the sheet raising plate can be lowered. - When the
sheet conveyance device 1201 rotates the pickup roller C3 in the sheet conveyance direction D1 with the top sheet pressed against the pickup roller C3, a sheet is fed from the sheet stacking tray T. Rotation of the sheet feed motor M2 as a drive source of the sheet feed roller C2 is transmitted to the pickup roller C3 via the timing belt, so that the pickup roller C3 is rotated. The sheet fed from the sheet stacking tray T enters a portion (a nip portion) in which the sheet feed roller C2 and the separation roller C1 are pressed against each other. The sheet feed roller C2 is rotated by the sheet feed motor M2 such that the sheet is fed in the sheet conveyance direction D1. The sheet feed roller C2 and the separation roller C1 pressed against each other nip the sheet. Acontroller 102 controls a position or a speed of the sheet feed motor M2. - The separation roller C1 is driven by the separation motor M1 via a predetermined driving force transmitter. In the present embodiment, a
controller 101 controls a return force to control the separation roller C1 via the separation motor M1 for the separation roller C1 without arraignment of a torque limiter as a predetermined driving force transmitter on a separation roller shaft. The separation motor M1 rotates the separation roller C1 in a direction opposite the sheet conveyance direction. However, when a single sheet is fed, thecontroller 101 controls the separation motor M1 by using torque to rotate the separation roller C1 in the sheet conveyance direction (a direction D2 illustrated inFIG. 1 while applying a return force). When two or more sheets are fed to the nip portion, thecontroller 101 controls the separation motor M1 by using torque to stop or rotate the separation roller C1 in an opposite direction (a direction D3 illustrated inFIG. 1 ). - If a plurality of sheets is fed from the pickup roller C3 with the sheets overlapped, rotation of the separation roller C1 in the direction D3 functions to return an excess sheet to the sheet stacking tray T since a friction between sheets is smaller than a friction between the separation roller C1 and a sheet. Accordingly, the sheet conveyance mechanism feeds the sheets one by one. A drive source for the separation roller C1 can be shared with the sheet feed motor M2, instead of arranging a drive source as the separation motor M1 dedicated to the separation roller C1.
- The present embodiment has been described using one example (a spring) of the separation
roller urging member 103 as a device that gives a pressure (a separation pressure) by which the separation roller C1 as a reverse roller is pressed to the sheet feed roller C2. However, as for such a device, a mechanism that causes a gear attached to a separation roller shaft to sprig up by a gear connected to a drive source may be used, or a configuration similar to a configuration of a conventional sheet conveyance device may be employed, instead of the spring. - In the configuration illustrated in
FIG. 1 , thesheet conveyance device 1201 includes the sheet stacking tray T, the pickup roller C3, the sheet feed roller C2, the sheet feed motor M2, a first encoder, thecontroller 102, the separation roller C1, the separation motor M1, a second encoder, thecontroller 101, and the separationroller urging member 103. The sheet stacking tray T serves as a sheet stacker on which sheets are stacked. The pickup roller C3 contacts the top sheet of the stack on the sheet stacker, and is rotated in the sheet conveyance direction D1. The sheet feed roller C2 as a feed roller is rotated to feed a sheet in the sheet conveyance direction D1. The sheet feed motor M2 as a first drive source rotates the pickup roller C3 and the sheet feed roller C2, and the first encoder detects a rotation amount of the sheet feed motor M2. Thecontroller 102 as a first drive controller controls a speed or a position of the first drive source based on the rotation amount detected by the first encoder. The separation roller C1 nips a sheet with the sheet feed roller C2 against which the separation roller C1 is pressed. The separation motor M1 as a second drive source rotates the separation roller C1, and the second encoder detects a rotation amount of the separation motor M1. Thecontroller 101 as a second drive controller performs torque control of the separation motor M1, and the separationroller urging member 103 as a separation pressure provider provides a pressure (a separation pressure) by which the separation roller C1 is pressed against the sheet feed roller C2. The torque control performed by the second drive controller controls a torque (a return force) such that the separation roller C1 is rotated with rotation of the sheet feed roller C2 in the direction D2 which is the same direction as the sheet conveyance direction D1 when a force having a predetermined value or more is applied from the sheet feed roller C2 in direct contact with the separation roller C1 or nipping a sheet with the separation roller C1. Moreover, the torque control performed by the second drive controller controls a torque (a return force) such that the separation roller C1 is rotated in a direction D3 opposite the sheet conveyance direction D1 when a force having a value less than the predetermined value is applied. With such control, a sheet that has been excessively fed is returned to the sheet stacking tray T as a sheet stacker if sheets are multi-fed. Thus, sheets are separated and fed one by one. In such a configuration, the separation motor M1 as the second drive source is a DC motor. Based on a relational expression between a motor rotation speed and an applied voltage that are measured beforehand for the DC motor and a torque of the DC motor, a reaction force estimation observer 201 (described below) as a torque estimation device calculates a turning angle speed from a rotation amount of the separation motor M1 detected by the second encoder, and then estimates a torque of the DC motor with an applied voltage to the DC motor from thecontroller 101 as the second drive controller. Such a configuration enables detection of multi-sheet feeding and control of multi-fed sheet separation to be performed in sheet conveyance (paper feeding) based on a torque of a motor that drives one roller contributed to the sheet conveyance. Thus, torque control is performed without an electric current detector (a sensor), and torque control of a reverse motor can be performed at lower cost than a conventional manner. -
FIG. 2 is a block diagram illustrating a control system of the separation motor M1 of thesheet conveyance device 1201. Thesheet conveyance device 1201 does not use an electric current detector (a sensor) to detect an electric current of a motor. Thesheet conveyance device 1201 inputs an output (a motor applied voltage) of thecontroller 101 and a motor shaft rotation speed measured by a sensor to the reactionforce estimation observer 201 to calculate an estimation value of a return force to a sheet as a reaction force estimation value, and performs feedback control. A plant C10 includes the separation motor M1 and a drive module such as the separation roller C1. An example of the reactionforce estimation observer 201 may have a known configuration as illustrated inFIG. 3 . In the example illustrated inFIG. 3 , a motor applied voltage and a motor shaft rotation speed are input to output an estimation value of a reaction force (torque). - In addition, as illustrated in
FIG. 4 , thesheet conveyance device 1201 can include amulti-sheet feed detector 401 that detects multi-sheet feeding. Themulti-sheet feed detector 401 monitors a rotation speed of the separation motor M1 to determine whether sheet separation is to be started as sheets are multi-fed. If themulti-sheet feed detector 401 determines that sheet separation is to be started, a target torque of the separation motor M1 is increased. InFIG. 4 , themulti-sheet feed detector 401 receives a rotation speed from the separation motor M1. If the rotation speed is a predetermined threshold value or greater and remains unchanged for a certain time period, themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, and instructs thecontroller 101 to change a target torque. - Accordingly, the
sheet conveyance device 1201 illustratedFIG. 1 includes themulti-sheet feed detector 401 which monitors a rotation amount (a rotation speed) of the separation motor M1 as the second drive source during sheet feeding. If the rotation speed falls below a predetermined value, themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed. If sheet separation is to be started as sheets are multi-fed, themulti-sheet feed detector 401 controls thecontroller 101 as the second drive controller to increase a target torque for torque control. Such control enables multi-sheet feeding to be detected without arrangement of a dedicated multi-sheet feed detection sensor. Moreover, since a return force is increased when only sheets are multi-fed, unnecessary return force is not applied during single-sheet feeding in which sheets are not multi-fed. Thus, a rubbing amount of a separation roller against a sheet can be reduced, and the lifetime of a component of the separation roller can be extended. -
FIG. 5 is a diagram illustrating times at which the multi-sheet feed detector illustrated inFIG. 4 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in rotation speed of the separation motor. - As illustrated in
FIG. 5 , in thesheet conveyance device 1201, after activation of the separation motor M1 is completed, a rotation speed of the separation motor M1 exceeds a threshold value V1, and themulti-sheet feed detector 401 starts monitoring the rotation speed of the separation motor M1 at a time T0. Subsequently, the rotation speed of the separation motor M1 may remain constant for a certain time period. In such a case, at a time T1, themulti-sheet feed detector 401 determines that sheets are multi-fed and instructs thecontroller 101 to change a target torque. Accordingly, thecontroller 101 changes the target torque such that the separation motor M1 is rotated in reverse for a certain time period. Then, themulti-sheet feed detector 401 increases the rotation speed of the separation motor M1 as similar to the situation prior to the time T1. When the rotation speed of the separation motor M1 exceeds a threshold value V2 that is used for determination of completion of the sheet separation, themulti-sheet feed detector 401 determines that the sheet separation is completed at a time T2 at which the rotation speed exceeds the threshold value V2, and conveyance of the sheet continues. - A threshold value (V1) to be used for determination of the start of sheet separation as sheets are multi-fed and a threshold value (V2) to be used for determination of completion of the sheet separation can be same value or different values. In
FIG. 5 , the separation motor M1 intends to rotate the separation roller C1 in a direction opposite the sheet conveyance direction. Thus, when separation of sheets is started as the sheets are multi-fed, the separation roller C1 is decelerated and rotated in reverse. When the separation is completed and the separation roller C1 is again rotated with a first sheet (the top layer sheet), the separation roller C1 is rotated in the sheet conveyance direction. -
FIG. 6 is a schematic diagram illustrating one example of thesheet conveyance device 1201 in which themulti-sheet feed detector 401 illustrated inFIG. 4 monitors a torque estimation value of the separation motor M1 to increase a target torque of the separation motor M1 if themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed. InFIG. 6 , themulti-sheet feed detector 401 receives a torque estimation value of the separation motor M1 from thecontroller 101. If the torque estimation value is a predetermined threshold value or greater and remains unchanged for a certain time period, themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, and instructs thecontroller 101 to change a target torque. - Accordingly, the
sheet conveyance device 1201 illustratedFIG. 6 includes themulti-sheet feed detector 401. Themulti-sheet feed detector 401 monitors torque (an estimation value provided by the reactionforce estimation observer 201 as a torque estimator) of the separation motor M1 as the second drive source during sheet feeding. Themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, if the toque estimation value falls below a predetermined value. If themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed, a target torque for torque control to be performed by thecontroller 101 as the second drive controller is increased. Hence, with such amulti-sheet feed detector 401, multi-sheet feeding can be detected by a method different from the method described with reference toFIG. 4 without a dedicated multi-sheet feed detection sensor. Moreover, since a return force is increased when only sheets are multi-fed, unnecessary return force is not applied during single-sheet feeding in which sheets are not multi-fed. Thus, a rubbing amount of a separation roller against a sheet can be reduced, and the lifetime of a component of the separation roller can be extended. -
FIG. 7 is a diagram illustrating times at which thesheet conveyance device 1201 illustrated inFIG. 6 determines that sheet separation is to be started as sheets are multi-fed and the sheet separation is completed from a change in torque estimation value. As illustrated inFIG. 7 , in thesheet conveyance device 1201, after activation of the separation motor M1 is completed, a torque estimation value of the separation motor M1 exceeds the threshold value V1, and themulti-sheet feed detector 401 starts monitoring the torque estimation value of the separation motor M1 at a time T0. Afterward, the torque estimation value of the separation motor M1 may remain constant for a certain time period without increasing. In such a case, themulti-sheet feed detector 401 determines that sheets are multi-fed at a time T3 at which the certain time has elapsed, and instructs thecontroller 101 to change a target torque. Accordingly, thecontroller 101 changes the target torque such that the separation motor M1 is rotated in reverse for a certain time period. Subsequently, themulti-sheet feed detector 401 increases the torque estimation value of the separation motor M1, as similar to the situation prior to the time T3. When the torque estimation value of the separation motor M1 exceeds a threshold value V2 that is used for determination of completion of the sheet separation, themulti-sheet feed detector 401 determines that the sheet separation is completed at a time T4 at which the torque estimation value exceeds the threshold value V2, and conveyance of the sheet continues. If a torque estimation value of the separation motor M1 is constant without increasing, themulti-sheet feed detector 401 can make a determination based on the presume that a slip of a lower sheet of multi-fed sheets with respect to an upper sheet by a return force from the separation roller C1 reduces a reaction force estimated by the reactionforce estimation observer 201. Accordingly, a time at which such a determination is made can be determined as a time T3 at which sheet separation is started as sheets are multi-fed. A threshold value (V1) to be used for determination of the start of sheet separation as sheets are multi-fed and a threshold value (V2) for determination of completion of the sheet separation can be same value or different values. - In the
sheet conveyance device 1201 illustrated in each ofFIGS. 4 and 6 , if determining that sheet separation is to be started as sheets are multi-fed, themulti-sheet feed detector 401 can perform control such that a target torque remains large until a sheet being conveyed passes. When such control can return the multi-fed sheet to the tray side, the separation roller C1 is rotated with a sheet in a sheet conveyance direction D1. In thesheet conveyance device 1201 illustrated inFIGS. 4 and 6 , if a rotation speed or a torque estimation value exceeds a predetermined value again, a target torque level is controlled to return to an initial value. However, in one embodiment of the present disclosure, even if a rotation speed or a torque estimation value exceeds a predetermined value again, a target torque level is controlled not to return to an initial value. Thus, a return operation can be performed promptly, even if sheets are multi-fed again. - In the
sheet conveyance device 1201 according to one embodiment of the present disclosure, as illustrated inFIG. 5 or 7 , after determining that sheet separation is to be started as sheets are multi-fed, themulti-sheet feed detector 401 continue to monitor a rotation amount (a rotation speed) of the separation motor M1 as the second drive source, or torque (an estimation amount provided by the torque estimation device) of the separation motor M1 as the second drive source. If the rotation amount (the rotation speed) of the second drive source or the torque (the estimation amount provided by the torque estimation device) of the second drive source exceeds a predetermined value, themulti-sheet feed detector 401 determines that the sheet separation is completed. Thecontroller 102 as a first drive controller stops the driving of the sheet feed motor M2 as the first drive source if themulti-sheet feed detector 401 determines that sheet separation is to be started as sheets are multi-fed. Thecontroller 102 resumes driving of the first drive source if themulti-sheet feed detector 401 determines that the sheet separation is completed. - In the
sheet conveyance device 1201 according to one embodiment of the present disclosure, as illustrated in each ofFIGS. 5 and 7 , thecontroller 102 as the first drive controller can reduce driving of the sheet feed motor M2 as the first drive source to a predetermined speed if themulti-sheet feed detector 401 determines that separation of sheets has been started as the sheets are multi-fed. Thecontroller 102 can control a speed of the first drive source to return to a normal speed if themulti-sheet feed detector 401 determines that the sheet separation is completed. Although such control provides lower multi-sheet feeding prevention effects than a configuration illustrated in each ofFIGS. 4 and 6 , a delay of sheet feeding operation when multi-sheet feeding prevention operation is performed can be reduced, and influence on a latter system can be reduced. -
FIG. 8A is diagram illustrating leading end positions 801 and 802 of a first sheet and a multi-fed sheet if the sheet feed motor M2 is not stopped, andFIG. 8B is a diagram illustrating leading end positions 803 and 804 of a first sheet and a multi-fed sheet if the sheet feed motor M2 is stopped according to one embodiment of the present disclosure. As illustrated inFIGS. 8A and 8B , thecontroller 101 stops the sheet feed motor M2 if multi-sheet feeding is detected from a position (P2) of a sheet feed separation portion as a nip portion formed by the separation roller C1 and the sheet feed roller C2 to a position (P1) of a conveyance roller disposed downstream in a conveyance direction. As illustrated inFIG. 8A , if the sheet feed motor M2 is not stopped, the leading end position 801 of the first sheet moves with time to the position (P1) of the conveyance roller disposed downstream in the conveyance direction. Meanwhile, as for the leading end position 802 of a lower sheet that is prevented by the separation roller C1 from being multi-fed, after the leading end position 802 intends to move to the position (P1) of the conveyance roller disposed downstream in the conveyance direction with the first sheet, the leading end position 802 remains unchanged even after a certain time period has elapsed. On the other hand, as illustrated inFIG. 8B , if the sheet feed motor M2 is stopped for a certain time period (TT), the leading end position 804 of a lower sheet does not intend to move to the position (P1) of the conveyance roller disposed downstream in the conveyance direction, and is not changed even after the certain time period has elapsed. That is, the sheet feed motor M2 is stopped, so that a multi-fed sheet is prevented from moving excessively, and a possibility that the multi-fed sheet may reach a downstream roller pair (a conveyance roller pair) can be reduced even more. -
FIG. 9 is a sectional view illustrating a schematic configuration of thesheet conveyance device 1201 according to one embodiment of the present disclosure. InFIG. 9 , thesheet conveyance device 1201 includes a conveyance-roller-pairsheet nipping determiner 903 in addition to the configuration illustrated inFIG. 4 . The conveyance-roller-pairsheet nipping determiner 903 determines whether a conveyance roller pair has nipped a sheet. InFIG. 9 , thesheet conveyance device 1201 includes a conveyance roller pair (a conveyance roller R1 and a counter roller R2), a conveyance motor M3 as a third drive source, a third encoder, acontroller 902 as a third drive controller, and the conveyance-roller-pairsheet nipping determiner 903 that are disposed downstream of thesheet conveyance device 1201 in the sheet conveyance direction D1 illustrated inFIG. 1 . The conveyance roller pair is pressed against each other to nip a sheet fed from thesheet conveyance device 1201. The conveyance motor M3 rotates the conveyance roller pair (or the conveyance roller R1). The third encoder detects a rotation amount of the conveyance motor M3. Thecontroller 902 controls a position or a speed of the conveyance motor M3. The conveyance-roller-pairsheet nipping determiner 903 uses asheet detector 901 such as a sensor to determine whether the conveyance roller pair has nipped a sheet. Thesheet detector 901 detects the presence or absence of a sheet in a position of the conveyance roller pair or a position slightly downstream of the conveyance roller pair. In thesheet conveyance device 1201 illustrated inFIG. 9 , if themulti-sheet feed detector 401 determines that a time at which sheet separation is to be started as sheets are multi-fed has come after the conveyance-roller-pairsheet nipping determiner 903 determines that the conveyance roller pair has nipped a sheet, thecontroller 902 stops the driving of the sheet feed motor M2. If themulti-sheet feed detector 401 determines that the sheet separation is completed, thecontroller 902 resumes the driving of the conveyance motor M3. Such control enables effects similar toFIGS. 4 and 6 to be obtained even when a second sheet or subsequent sheets enter a portion in which the sheet feed roller C2 and the separation roller C1 forming a sheet feed separation portion are in contact with each other after a first sheet reaches the conveyance roller pair. - In the
sheet conveyance device 1201 illustrated inFIG. 9 , as one embodiment of the present disclosure, if themulti-sheet feed detector 401 determines that separation of sheets has been started as the sheets are multi-fed after the conveyance-roller-pairsheet nipping determiner 903 determines that the conveyance roller pair has nipped a sheet, thecontroller 902 reduces the driving of the conveyance motor M3 to a predetermined speed. If themulti-sheet feed detector 401 determines that the sheet separation is completed, thecontroller 902 returns the speed of the conveyance motor M3 to a normal speed. Such control enables effects similar toFIGS. 4 and 6 to be obtained, even if a second sheet or subsequent sheets enter a portion in which the sheet feed roller C2 and the separation roller C1 forming a sheet feed separation portion are in contact with each other after a first sheet reaches the conveyance roller pair. - Moreover, in the
sheet conveyance device 1201 illustrated inFIG. 9 , as one embodiment of the present disclosure, if the conveyance-roller-pairsheet nipping determiner 903 determines that the conveyance roller pair has nipped a sheet, thecontroller 102 as the first drive controller can stop the driving of the sheet feed motor M2 as the first drive source. Such control enables a sheet to be conveyed by only the conveyance roller pair, so that energy saving effect can be obtained. As illustrated inFIGS. 10 and 11 , a function of thecontroller 102 can be included in thecontroller 101, so that thesheet conveyance device 1201 can include a single controller. With such arrangement, thesheet conveyance device 1201 can be made more compact -
FIG. 12 is a diagram illustrating an example of a sheettype input portion 1202 according to the present embodiment. Thesheet conveyance device 1201 includes asheet stacking tray 1203, a sheetejection port tray 1204 to which a sheet is ejected, and a sheet type input device including the sheettype input portion 1202. The sheettype input portion 1202 is used to input (select) a sheet type. - The
sheet conveyance device 1201 which has been described with reference to the drawings can include the sheet type input device including the sheettype input portion 1202 to which a sheet type can be input by a user. At least one of a predetermined value of rotation speed or torque estimation value, a target torque, and a value of target torque at the time of multi-sheet feeding can be changed depending on the sheet type input from the sheet type input device. Such a configuration enables a suitable return force to be set according to a sheet type (characteristic), so that multi-sheet feed prevention performance (separability) can be enhanced, and a rubbing amount of a separation roller against a sheet can be reduced. -
FIG. 13 is a sectional view illustrating animage forming apparatus 1000 according to one embodiment. Theimage forming apparatus 1000 illustrated inFIG. 13 is an electrophotographic tandem-type indirect-transfer color copier (hereinafter simply referred to as a copier), and a schematic configuration illustrated inFIG. 13 is one example of an internal mechanical part of the copier. Theimage forming apparatus 1000 includes acopier body 100 as an image forming apparatus body, asheet conveyance device 200 on which thecopier body 100 is placed, ascanner 300 that is attached on thecopier body 100, and an automatic document feeder (ADF) 400 that is attached on thescanner 300. - In a middle portion of the
copier body 100, anintermediate transfer body 10 of an endless belt is stretched by adrive roller 14 and two drivenrollers FIG. 13 . Theintermediate transfer body 10 may be stretched by four or more rollers including a roller that adjusts deviation of theintermediate transfer body 10. In the example illustrated inFIG. 13 , theintermediate transfer body 10 is stretched in a substantially horizontal manner. However, theintermediate transfer body 10 may be diagonally stretched, instead of being horizontally stretched. - In the example illustrated in
FIG. 13 , thecopier body 100 also includes abelt cleaning device 17 on the left side of the drivenroller 15 which is one of the driven rollers. Thebelt cleaning device 17 removes residual toner remaining on theintermediate transfer body 10 subsequent to transfer of an image. - A tandem
image formation device 20 is disposed on theintermediate transfer body 10 which is horizontally stretched between thedrive roller 14 and the drivenroller 15. The tandemimage formation device 20 includes four single-colorimage formation devices intermediate transfer body 10. In addition, anexposure device 21 is disposed above the tandemimage formation device 20. - A
secondary transfer device 22 is disposed below an area in which theintermediate transfer body 10 is stretched. In the example illustrated inFIG. 13 , thesecondary transfer device 22 includes asecondary transfer belt 24 of an endless belt that is stretched between tworollers 23 and is pressed against the drivenroller 16 to transfer an image on theintermediate transfer body 10 to a recording medium. - A fixing
device 25 that fixes the transferred image on the recording medium is disposed beside thesecondary transfer device 22. The fixingdevice 25 is configured to press apressure roller 27 against a fixingbelt 26 of an endless belt. In the example illustrated inFIG. 13 , one portion of the fixingdevice 25 is (the entire portion of the fixingdevice 25 can be) arranged below the area in whichintermediate transfer body 10 is stretched. Thesecondary transfer device 22 also has a recording medium conveyance function of conveying the recording medium with the transferred image to the fixingdevice 25. Alternatively, a non-contact charger may be disposed as thesecondary transfer device 22. In such a case, however, the non-contact charger as thesecondary transfer device 22 has a difficulty in having such a recording medium conveyance function. - A recording
medium reverse device 28 is disposed below thesecondary transfer device 22 and the fixingdevice 25. The recordingmedium reverse device 28 is disposed parallel to a direction in which theintermediate transfer body 10 is stretched. The recordingmedium reverse device 28 reverses a recording medium to form images on two sides of the recording medium. - When such a copier is used to make a copy, a document is set on a
document tray 30 of theADF 400 or theADF 400 is opened to directly set a document on anexposure glass 32, and theADF 400 is closed to hold the document with theADF 400. Subsequently, a start switch is pressed. If the document is set on theADF 400, the document is conveyed and moved to theexposure glass 32, and then thescanner 300 is driven to read the contents of the document. If the document is directly set on theexposure glass 32, the content of the document is read by thescanner 300 without conveyance of the document. - Moreover, when the start switch is pressed, the
drive roller 14 is rotated by a drive motor and the drivenrollers drive roller 14 to rotate theintermediate transfer body 10. At the same time, in the single-colorimage formation devices image bearers image bearers intermediate transfer body 10, so that combined color images are formed on theintermediate transfer body 10. - Meanwhile, one of
pickup rollers 42 of thesheet conveyance device 200 is selected and rotated at an appropriate time after the start switch is pressed. Then, recording media are fed from one of a plurality ofsheet stacking trays 44 in asheet bank 43. The recording media are separated one by one by aseparation roller 45 and enter separately asheet conveyance path 46. The recording medium is then conveyed by aconveyance roller 47 and is guided to asheet feed path 48 inside thecopier body 100. When the recording medium contacts aregistration roller 49, the conveyance of the recording medium stops. If recording media are manually fed, the recording media set on amanual feed tray 51 that is opened with rotation of asheet feed roller 50 are fed. Then, the recording media are separated one by one by aseparation roller 52 and enter separately a manual feedsheet conveyance path 53. As similar to the above, the recording medium contacts theregistration roller 49, and the conveyance of the recording medium stops. - The
registration roller 49 is rotated to time with the combined color images on theintermediate transfer body 10, and the recording medium is fed between theintermediate transfer body 10 and thesecondary transfer device 22. Thesecondary transfer device 22 secondarily transfers the combined color images on theintermediate transfer body 10 to the recording medium in a collective manner to form a color image on the recording medium. - The recording medium with the transferred image is conveyed by the
secondary transfer device 22 to the fixingdevice 25. After the fixingdevice 25 applies heat and pressure to the recording medium to fix the transferred image, a conveyance direction of the recording medium is switched by a switchingpawl 55 and the recording medium is ejected by anejection roller 56. The ejected recording medium is stacked on anejection tray 57. If images are to be formed on two sides of the recording medium, a conveyance direction of the recording medium is switched by the switchingpawl 55 and the recording medium enters the recordingmedium reverse device 28. The recording medium is reversed in the recordingmedium reverse device 28. The reversed recording medium is guided to a transfer position again, and an image is formed on the back surface of the recording medium. Subsequently, the recording medium is ejected by theejection roller 56 to theejection tray 57. - The
belt cleaning device 17 removes a residual toner remaining on theintermediate transfer body 10 after the image is transferred, and theintermediate transfer body 10 becomes ready again for image formation to be performed by the tandemimage formation device 20. - In such an
image forming apparatus 1000, a device that supplies sheet-type recording media such as paper is disposed. Thesheet conveyance device 1201 according to the embodiment can be applied to such a device for supplying recording media. The application of thesheet conveyance device 1201 can provide an image forming apparatus that reduces a degree of degradation of a separation roller at lower cost while maintaining or enhancing multi-sheet feed prevention performance (separability). - The present disclosure has been described above with reference to specific embodiments but is not limited thereto. Various modifications and enhancements are possible without departing from scope of the disclosure. It is therefore to be understood that the present disclosure may be practiced otherwise than as specifically described herein. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present disclosure.
- Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
- Each of the functions of the described embodiments may be implemented by one or more processing circuits or circuitry. Processing circuitry includes a programmed processor, as a processor includes circuitry. A processing circuit also includes devices such as an application specific integrated circuit (ASIC), digital signal processor (DSP), field programmable gate array (FPGA), and conventional circuit components arranged to perform the recited functions.
- Program codes executed by the image processing apparatus to achieve the functions of the described embodiments may be provided in files in an installable format or an executable format that are recorded on computer-readable recording media such as a CD-ROM, a flexible disk (FD), a CD-R, and a digital versatile disk (DVD). The program codes executed by the image processing apparatus may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network, or be provided or distributed via a network such as the Internet.
Claims (13)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020051103A JP7456222B2 (en) | 2020-03-23 | 2020-03-23 | Conveyance device and image forming device |
JP2020-051103 | 2020-03-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20210292116A1 true US20210292116A1 (en) | 2021-09-23 |
Family
ID=77747544
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/191,854 Abandoned US20210292116A1 (en) | 2020-03-23 | 2021-03-04 | Conveyance device and image forming apparatus |
Country Status (2)
Country | Link |
---|---|
US (1) | US20210292116A1 (en) |
JP (1) | JP7456222B2 (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7455286B2 (en) * | 2005-06-28 | 2008-11-25 | Hewlett-Packard Development Company, L.P. | Sheet separation using two torque motors |
US7658374B2 (en) * | 2005-02-07 | 2010-02-09 | Pfu Limited | Sheet feeder |
US20200174415A1 (en) * | 2018-11-30 | 2020-06-04 | Ricoh Company, Ltd. | Sheet conveying device and image forming apparatus incorporating the sheet conveying device |
US10807818B2 (en) * | 2017-10-24 | 2020-10-20 | Canon Kabushiki Kaisha | Sheet feeding apparatus and image forming apparatus |
US20200361731A1 (en) * | 2019-05-17 | 2020-11-19 | Lexmark International, Inc. | Automatic Document Feeder Multi-Feed Corrector |
US20210284472A1 (en) * | 2020-03-16 | 2021-09-16 | Ricoh Company, Ltd. | Sheet feeding device, image forming apparatus, and control method |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4184904B2 (en) | 2003-09-03 | 2008-11-19 | 株式会社東芝 | Paper sheet separating and conveying device |
JP2009051590A (en) | 2007-08-24 | 2009-03-12 | Fuji Xerox Co Ltd | Paper feeding device and image forming device using the same |
JP2014196194A (en) | 2013-03-05 | 2014-10-16 | 株式会社リコー | Sheet feeder and image formation apparatus |
JP2015080398A (en) | 2013-09-13 | 2015-04-23 | 株式会社リコー | Load torque estimation device, image formation device, load torque estimation method, and program |
JP6977451B2 (en) | 2017-09-28 | 2021-12-08 | セイコーエプソン株式会社 | Media feeder, image reader, recording device |
-
2020
- 2020-03-23 JP JP2020051103A patent/JP7456222B2/en active Active
-
2021
- 2021-03-04 US US17/191,854 patent/US20210292116A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7658374B2 (en) * | 2005-02-07 | 2010-02-09 | Pfu Limited | Sheet feeder |
US7455286B2 (en) * | 2005-06-28 | 2008-11-25 | Hewlett-Packard Development Company, L.P. | Sheet separation using two torque motors |
US10807818B2 (en) * | 2017-10-24 | 2020-10-20 | Canon Kabushiki Kaisha | Sheet feeding apparatus and image forming apparatus |
US20200174415A1 (en) * | 2018-11-30 | 2020-06-04 | Ricoh Company, Ltd. | Sheet conveying device and image forming apparatus incorporating the sheet conveying device |
US11126127B2 (en) * | 2018-11-30 | 2021-09-21 | Ricoh Company, Ltd. | Sheet conveying device and image forming apparatus incorporating the sheet conveying device |
US20200361731A1 (en) * | 2019-05-17 | 2020-11-19 | Lexmark International, Inc. | Automatic Document Feeder Multi-Feed Corrector |
US20210284472A1 (en) * | 2020-03-16 | 2021-09-16 | Ricoh Company, Ltd. | Sheet feeding device, image forming apparatus, and control method |
Also Published As
Publication number | Publication date |
---|---|
JP2021147220A (en) | 2021-09-27 |
JP7456222B2 (en) | 2024-03-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9517905B2 (en) | Separation conveyance device, image forming apparatus, method for controlling separation conveyance device, and computer-readable recording medium | |
US7392980B2 (en) | Sheet feed device and image forming apparatus | |
US10800624B2 (en) | Image forming apparatus | |
US8322718B2 (en) | Recording medium conveyer capable of effectively conveying recording medium of various types | |
US11102375B2 (en) | Sheet reading apparatus for detecting the shadow of a conveyed sheet to determine an inclination | |
US9873576B2 (en) | Sheet feeding apparatus and image forming apparatus | |
US9387999B2 (en) | Sheet feeding device and image forming apparatus | |
US8454011B2 (en) | Sheet feeder and image forming apparatus incorporating same | |
US8827258B2 (en) | Recording medium transport device, and image forming apparatus | |
US8678382B2 (en) | Sheet conveyance apparatus and image forming apparatus | |
US9296576B2 (en) | Medium conveying device and image forming apparatus | |
JP2020075820A (en) | Sheet feeder | |
US9860403B2 (en) | Sheet feeding apparatus, and reading apparatus and image forming apparatus using the same | |
US20130264767A1 (en) | Skew correction apparatus and image forming apparatus | |
US20160060071A1 (en) | Sheet discharging device and image forming apparatus provided with same | |
US20210292116A1 (en) | Conveyance device and image forming apparatus | |
JP7321805B2 (en) | Sheet feeding device, image reading device and image forming device | |
US10906760B2 (en) | Sheet feeding apparatus and image forming apparatus | |
US20200174415A1 (en) | Sheet conveying device and image forming apparatus incorporating the sheet conveying device | |
US10775730B2 (en) | Sheet feeding apparatus and image forming apparatus | |
JP6669989B2 (en) | Paper feeder and image forming apparatus | |
US20240051775A1 (en) | Sheet feeding device and image forming apparatus incorporating the sheet feeding device | |
JP2004210488A (en) | Reader | |
JP3717465B2 (en) | Sheet separating and feeding apparatus, and image reading apparatus and image forming apparatus provided with the apparatus | |
JP2011073844A (en) | Paper feeding device and image forming device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: RICOH COMPANY, LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAKAYAMA, HIDEYUKI;REEL/FRAME:055490/0715 Effective date: 20210302 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |