JP4478273B2 - Sheet conveying apparatus and image processing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus that reduces operating noise particularly in an image forming apparatus such as a scanner, a copying machine, and a facsimile machine that reads an image on a sheet, and an image forming apparatus such as a printer.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various sheet conveying apparatuses that are provided in an image processing apparatus such as a scanner or a copying machine and automatically convey a sheet have been proposed. An example of a sheet conveying apparatus used in a conventional image reading apparatus will be described with reference to FIG. A sheet conveying apparatus 501 shown in the figure is installed on the upper part of the image reading apparatus 500 and conveys a plurality of originals P as sheet materials stacked on an original tray 502 to the reading unit 500a of the image reading apparatus 500, and The upper image is read.
[0003]
The documents P stacked on the document tray 502 are fed by the pickup roller 503 and separated one by one by the separation roller 504 and the separation pad 505 of the separation unit, and then placed above the reading unit 500a by the conveyance roller pair 506. The large roller 507 is conveyed. Pressure rollers 508, 509, and 510 are pressurized and driven by the large roller 507, and the document P is nipped and conveyed to the reading unit 500a. The image reading apparatus 500 reads an image on the document being conveyed from the reading unit 500a in the reading unit 500a.
[0004]
On the downstream side of the large roller 507, there are provided a discharge roller 511 and a discharge roller 512 configured to be detachable from the discharge roller 511, and are configured to sandwich and convey the document P. The discharge roller 511 has a large roller 507 and a drive source, and is configured to be able to rotate forward and backward. The discharge roller 511 discharges the document P to the discharge tray 513 by forward rotation and reverses the document P by reverse rotation. is there.
[0005]
The document P shown in FIG. 17 shows a state where the image reading on the front surface is finished and the image reading on the back surface (opposite surface) is performed after the switchback reversal operation. The discharge roller 512 is driven by a solenoid (not shown) to come in contact with and is provided with a mechanism that pressurizes the discharge roller 511 when the solenoid is turned on and separates it when the solenoid is turned off. The discharge roller 512 is separated from the discharge roller 511 during image reading, and pressurizes and discharges and switches back after the reading is finished. However, as shown in FIG. It is controlled to be separated.
[0006]
[Problems to be solved by the invention]
However, in the sheet conveying apparatus having the above-described configuration, the discharge roller 512 is pressed against or separated from the discharge roller 511 every time the sheet is conveyed and particularly when the discharge and switchback are performed. There has been a problem that the operation noise of the apparatus is increased because the drive mechanism and the drive source solenoid are operated many times. Specifically, the contact / separation operation generated abrupt sounds, such as a housing contact sound when the plunger of the solenoid was attracted, a contact sound caused by backlash between the drive mechanisms, and a contact sound when the roller was pressed. .
[0007]
For example, in the single-sided reading mode, the operation is performed twice in total, once for pressurization for discharging one original and once for separation at the end of the job. Therefore, when the number of originals is N, the operation is performed N × 2. Also, in the double-sided reading mode, one press is applied for switching back after scanning the front side of each original, once separated for passing before scanning the back side, and once again for switching back after scanning the back side, Therefore, since the second separation is performed, the third pressurization is performed for discharging, and the third separation is performed at the end of the job, a total of six operations are performed. Note that the second switchback is an idling conveyance performed in order to adjust the page order of the documents stacked on the discharge tray 513.
[0008]
SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus in which the operation noise of the apparatus is reduced and an image reading apparatus including the sheet conveying apparatus.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a typical configuration of a sheet conveying apparatus according to the present invention is arranged on a downstream side of a conveying unit that conveys a sheet to an image reading unit or an image forming unit, A discharge reversing unit that rotates forward and backward to discharge the sheet or re-feed the sheet to the conveying unit;
A sheet nipping unit that can be pressed and separated from the discharge reversing unit; and a size detection unit that detects a length in the conveyance direction of the sheet. , In the mode in which the sheet is re-fed by the discharge reversing unit, at least the length of the sheet in the conveying direction is the same as that of the leading edge of the sheet and the rear of the sheet when the sheet is re-fed. When the length of the end passes each other, The discharge reversing means pressurizes the sheet sandwiching means to convey the sheet in the discharge direction between the discharge reversing means and the sheet sandwiching means, and then re-feeds the sheet in the discharge reversing means and the sheet. After the sheet is conveyed by the nipping means, the sheet nipping means is separated from the discharge reversing means, and after the leading edge of the sheet conveyed in the refeeding direction reaches the discharge reversing means and the trailing edge of the sheet After the section has passed through the discharge reversing means, the sheet reversing means pressurizes the sheet sandwiching means, the sheet is conveyed by the discharge reversing means and the sheet sandwiching means, and the sheet is re-fed by the discharge reversing means. In this mode, when the length of the sheet in the transport direction is such that when the sheet is fed again, the discharge reversing means does not pass the leading edge and trailing edge of one sheet. It said sheet clamping means during preparative conveyed without separating from the discharge reversal unit, In the mode in which the sheet is discharged without refeeding by the discharge reversing unit, when the length of the sheet detected by the size detection unit is a predetermined value or more, The discharge reversing means is pressed against the discharge reversing means so as to hold the sheet conveyed with the sheet holding means spaced from the discharge reversing means, and after the sheet is discharged, the sheet holding means is discharged. Away from the reversing means, When the length of the sheet detected by the size detection means is shorter than a predetermined value Is The sheet holding means is always pressurized to the discharge reversing means during sheet conveyance.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a sheet conveying apparatus and an image reading apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a sheet conveying device according to the present embodiment, FIG. 2 is a diagram illustrating a configuration of an image reading device according to the present embodiment, and FIG. 3 is a diagram illustrating a drive system of the sheet conveying device. 4 is a diagram for explaining the configuration of the evacuation unit, FIG. 5 is a block diagram for explaining the circuit configuration of the control device, FIGS. 6 to 11 are diagrams for explaining the document reading operation, and FIG. 12 is a mode selection for image reading. FIG. 13 to FIG. 16 are flowcharts for explaining the document reading operation.
[0011]
(overall structure)
The image reading apparatus shown in FIG. 2 is a copying machine, and has an image input unit 1 at the top of the apparatus and an image output unit 2 at the bottom of the apparatus. Furthermore, a sheet conveying device described later is provided above the image input unit 1. In the following description, the sheet conveying apparatus is simply referred to as ADF5 (Auto Document Feeder).
[0012]
(Image output part)
First, the image output unit 2 will be described with reference to FIG. In the image output unit 2, sheet-like recording materials are stacked and stored in the upper cassette 10, the lower cassette 11, and the deck 12, and are separated one by one by a separation claw and a feeding roller 13 (not shown). Be fed. Further, the image output unit 2 is provided with a manual feed guide 14 so that the recording material can be individually fed.
[0013]
The photosensitive drum 16 as an image carrier is uniformly charged by a primary charging unit 17 and is irradiated with light by an optical unit (not shown) to form an electrostatic latent image. The electrostatic latent image is developed by a developing unit 18. A toner image is formed by developing the image. The registration roller pair 15 conveys the recording material in synchronization with the photosensitive drum 16, and after the toner image on the photosensitive drum 16 is transferred to the recording material by the transfer charger 19, the recording material is peeled off from the photosensitive drum by the separation charger 20. Let The transfer residual toner remaining on the photosensitive drum 16 is removed by the cleaner 21, and the photosensitive drum 16 is used for the next image formation. The recording material to which the toner image has been transferred is conveyed to the fixing device 23 by the conveying belt 22, and the image is fixed by applying heat and pressure. The recording material on which the image is fixed is selectively conveyed by the diverter 24 to the post-processing device 3 or the reconveying path 4.
[0014]
The post-processing device 3 is a sorter, and has a non-sort tray 3a, a sort bin tray 3b, a non-sort tray discharge roller 3c, and a sort bin tray discharge roller 3d. Divide the materials one by one. In some cases, a discharge tray is mounted instead of the sorter. In the case of duplex copying and multiple copying, the recording material after fixing is guided to the transport roller 25 of the re-transport path 4 by the diverter 24. In the case of double-sided copying, the recording material passes through the transport belts 27 and 29, the reverse path 30, and the discharge roller 31. Are discharged to the intermediate tray 26. In the case of multiple copying, the recording material is discharged from the conveying belt 27 to the intermediate tray 26 by the diverter 28. The recording material discharged to the intermediate tray 26 is fed again by the half-moon rollers 32 and 33, separated one by one by the separation roller pair 34, and conveyed again to the registration roller pair 15.
[0015]
(Image input part)
An image input unit 1 shown in FIG. 1 is a well-known image reading means, which optically reads image information recorded on a document as a sheet, photoelectrically converts it, and inputs it as image data. The image input unit 1 has a flow reading platen 36 and a book platen 37 on the upper surface. Further, a scanner unit 38 having a lamp 39 and a mirror 40, mirrors 41 and 42, a lens 43, an image sensor 44, and the like are provided inside the apparatus.
[0016]
When reading a document of ADF 5 described below, the scanner unit 38 is flown and fixed to the image reading unit 45 of the reading platen 36, and image reading is performed on the conveyed document. When reading a document placed on the book platen 37, the image is read while moving the scanner unit 38 along the book platen 37. At this time, the mirrors 41 and 42 move at a predetermined ratio as the scanner unit 38 moves so that the optical path length is constant.
[0017]
(Sheet conveying device)
As shown in FIG. 1, an ADF 5 that is a sheet conveying apparatus according to the present invention is provided on the upper portion of the image input unit 1. The ADF 5 continuously conveys the original to the flow reading platen 36 of the image input unit 1 and has a function of pressing the original on the book platen 37 by opening and closing the whole. Note that the present invention may be an image reading apparatus in which the image input unit 1 and the ADF 5 are integrally configured.
[0018]
A document tray 50 is disposed above the ADF 5, and sheets for reading images are stacked. The document tray 50 is provided with a pair of width direction regulating plates 51 slidable in the document width direction. By regulating the width direction of the documents stacked on the document tray 50 by the width direction regulating plate 51, it is possible to ensure the conveyance stability at the time of feeding. A swinging stopper 52 is disposed at the end of the document tray 50, and the document loaded on the document tray 50 is regulated by the stopper 52 protruding into the conveyance path so as not to advance downstream. .
[0019]
An arm 54 is pivotally supported above the document tray 50 so as to be swingable about the separation conveyance roller 55 as a rotation center, and a feeding roller 53 is provided at the tip of the arm 54. The feeding roller is normally retracted upward (solid line position in FIG. 1) as an initial position so as not to obstruct the document stacking operation. When the feeding operation is started, the arm 54, together with the stopper 52, swings to the dotted line position in the drawing, and the feeding roller 53 is pressed against the uppermost paper sheet so that feeding can be performed. The feeding roller 53 rotates in conjunction with the rotation driving of the separation conveying roller 55 and picks up a document. A separation pad 56 is disposed on the opposite side of the separation conveyance roller 55 and is pressed against the separation conveyance roller 55. The separation pad 56 is formed of a rubber material or the like whose friction is slightly smaller than that of the separation conveyance roller 55, and separates the documents fed by the feeding roller 53 one by one and conveys them to the registration roller pair 57. The registration roller pair 57 aligns the leading edge of the document fed in the separation unit, and stops the document by stopping the rotation to abut the leading edge of the document to correct skew.
[0020]
The large roller 58 is located above the flow-reading platen 36 and grips the document by forming the outer periphery with rubber. Further, pressure rollers A 59, 60, 61 are pressed on the large roller 58, and the document is nipped and conveyed while being wound around the large roller 58 by being driven by the large roller 58. The pressure rollers A59 and 60 are made of a resin having high slidability such as polyacetal. The pressure roller C61 is formed by forming the core material with a resin having high slidability such as polyacetal and winding the outer periphery back with urethane rubber so that the leading edge of the document can be easily guided to the nip portion with the large roller 58. Yes.
[0021]
A white plate 62 facing the flow reading platen 36 is disposed between the pressure rollers B60 and 61, and the image reading unit 45 reads an image while the white plate 62 is conveyed. Since the white plate 62 is arranged, the background is white even when the original is thinly transparent and does not affect the image. Further, immediately after the flow reading platen 36 of the image input unit 1, a jump table 46 for scooping up the original from the flow reading platen 36 is provided.
[0022]
The document guided from the large roller 58 passes through the deflection guide 63 and is guided to the nip of the discharge roller 64 which is a discharge reversing unit and the discharge roller 65 which is a sheet clamping unit which can be separated from and attached to the discharge roller 64. The deflection guide 63 guides the document to the switchback path 91 when the document is switched back by the discharge roller 64 after the trailing edge of the document has passed. The discharge roller 64 can be rotated forward and backward by driving means described later, and the document is discharged to the discharge tray 67 by forward rotation (counterclockwise in the figure), and the document is switched back by reverse rotation, via a switchback path 91. Then re-feed to the large roller 58. When the discharge roller 65 is pressed against the discharge roller 64, the discharge roller 65 is driven to rotate and pinch and convey the original, and when separated, the conveyance roller 65 does not interfere with the conveyance.
[0023]
(Drive system)
FIG. 3 is a diagram for explaining a drive system such as a motor and a solenoid for driving each roller. The separation solenoid 68 drives the swing of the arm 54 and the stopper 52. The separation solenoid 68 normally lifts the arm 54 and the stopper 52 upward (solid line position in FIG. 1) as an initial position and holds it at a position that does not hinder the document stacking operation. When the feeding operation is started, the holding of the separation solenoid 68 is released, and the feeding roller is swung to the dotted line position in the figure by the urging force of the tension spring 69, and the feeding roller is placed on the uppermost sheet of the documents stacked on the document tray 50. While pressing 53, the stopper 52 is lowered to enable paper feeding.
[0024]
The separation motor 70 is a stepping motor that can rotate forward and backward, and rotationally drives the feeding roller 53 and the separation transport roller 55 in the transport direction during normal rotation, and rotationally drives the registration roller pair 57 in the transport direction during reverse rotation. The separation motor 70 and the registration roller pair 57 are drivingly connected via a one-way gear (not shown) so that the registration roller pair 57 does not rotate during normal rotation of the separation motor 70. Similarly, the separation conveying roller 55 is also connected by driving through a one-way gear so that the drive is not transmitted when the separation motor 70 is rotated in reverse.
[0025]
The read motor 71 is a stepping motor that drives the large roller 58, and rotates the large roller 58 at a speed at which an image of a conveyed document is read.
[0026]
The reject motor 72 is a stepping motor capable of rotating forward and reverse to drive the reject roller. At the time of normal rotation, the original is rotated in a direction for discharging it to the discharge tray 67, and at the time of reverse rotation, it is rotated in a direction for re-feeding the large roller 58 via the switchback path 91. That is, reverse rotation is performed at the time of switchback in the double-sided mode described later.
[0027]
The discharge solenoid 73 is a solenoid for pressing or separating the discharge roller 65 toward the discharge roller 64. As shown in FIG. 4, a hook-like link 74 that pivotally supports a discharge roller 65 at one end is pivotally supported by a center 74a. Usually, the discharge roller 65 is moved by a tension spring 75 to a discharge roller. It is made to wait in the position away from 64 (solid line position in FIG. 4). When the discharge solenoid 73 is energized and the plunger 73a is sucked until the stopper 73b comes into contact with the housing 73c, the link 74 swings in conjunction with this and presses the discharge roller 65 against the discharge roller 64. When the energization of the discharge solenoid 73 is released, the discharge roller 65 returns to the position away from the discharge roller 64 again by the urging force of the tension spring 75.
[0028]
(Detection means)
Next, detection means provided in the ADF 5 will be described. On the document tray 50, a tray sensor 76 is arranged as a size detection means for detecting the length in the conveyance direction of the stacked documents. Since the tray sensor 76 is arranged at a predetermined value that is OFF when the document is a small size and ON when the document is a large size, the tray sensor 76 can determine whether the document is a small size or a large size.
[0029]
In the present embodiment, the predetermined value for the small size is set to 300 mm or less in the document conveyance direction length, and 300 mm or more is referred to as the large size. Accordingly, the tray sensor 76 is disposed at a position 300 mm from the document setting position. The length of the small size is a length that prevents the document from passing by the discharge roller 64 in the double-side mode described later.
[0030]
The discrimination between the small size and the large size is not limited to the method performed by the tray sensor 76, and a timing signal of a sheet detection sensor being conveyed, for example, a separation sensor may be used. In addition, the predetermined value is not limited to 300 mm, and in the duplex mode, a document having a length that passes by the discharge roller 64 may be a large size, and a document having a length that does not pass may be a small size. In addition, if it is a standard size, A4 size (210 mm) or LTR size (215.9 mm, 8.5 inches), which is frequently used, may be used as a standard, and smaller sizes may be used as a small size. For example, LTR, STMT, A4, B5, A5, and A6 are set as small sizes, and LDR, LGL, LTR length, A3, B4, A4 length, and B5 length are set as large sizes.
[0031]
Further, instead of providing the tray sensor 76, an operation unit (input means) (not shown) is provided as an input means on the outer surface of the apparatus, and the user manually inputs the size of the document, and based on the value, whether the document is a small size or a large size. It can also be configured to determine
[0032]
A width detection sensor 77 that detects the length in the width direction of the documents stacked on the document tray 50 by detecting the position of the width direction regulating plate 51 is provided below the document tray 50. Further, in the vicinity of the upstream portion of the stopper 52, there is provided a document stacking detection sensor 78 which is a transmission type optical sensor that detects that a document bundle is stacked. Similarly, a separation sensor 79, which is a transmission type optical sensor for detecting a document, is provided between the separation conveyance roller 55 and the registration roller pair 57, and detects the leading edge of the separated and fed document to the registration roller pair 57. The timing to control the amount of bumping is detected.
[0033]
A lead sensor 80, which is a sheet reflection type optical sensor for detecting a document, is provided on the upstream side of the pressure roller B60, and detects the image reading timing when the document enters the image reading unit 45. A discharge sensor 81, which is a transmissive optical sensor for detecting a document, is provided on the upstream side of the discharge roller 64, and detects a document discharge timing, a switchback start timing, and the like.
[0034]
(Control circuit)
The circuit configuration of the control device for the ADF 5 according to the present embodiment will be described with reference to FIG. The control circuit is mainly configured by a CPU 82 (microprocessor), and a drive circuit for various loads and the sensors 76 to 81 are connected to an input / output port of the CPU 82. The control circuit includes a RAM 83 that is backed up by a battery (not shown) and a ROM 84 that stores control sequence software. The CPU 82 is connected to the copying machine main body through an IC 85.
[0035]
The separation motor 70 and the lead motor 71 are driven by each stepping motor driver. Each driver receives a phase excitation signal and a motor current control signal from the CPU 82. The separation solenoid 68 and the discharge solenoid 73 are driven by a solenoid driver, and their operations are controlled by signals sent from the input / output port of the CPU 82.
[0036]
Various sensors such as a tray sensor 76, a width detection sensor 77, a document stacking detection sensor 78, a separation sensor 79, a read sensor 80, and a discharge sensor 81 are connected to the input port of the CPU 82, and the behavior of the document in the apparatus and the movable load Used to monitor the behavior of
[0037]
(Operation)
A document feeding operation in the sheet conveying apparatus having the above configuration will be described. First, when a copy condition is input from an operation unit (not shown) and the start key is pressed, the presence of a document is confirmed by a document stack detection sensor 78 on the document tray 50 (M1) as shown in FIG. The width detection sensor 77 detects the document size (M2). Then, in the case of the small size (M3) and the case of the large size (M7), it is determined whether the input copying conditions are one side or both sides (M4, M8), the small size one side mode (M5), One of the size double-side mode (M6), the large size single-side mode (M9), and the large size double-side mode (M10) is selected.
[0038]
The small size single-sided mode (M5) will be described with reference to the flowcharts of FIG. 6 and FIG. First, the discharge solenoid 73 is turned on (SS1), and the discharge roller 65 presses the discharge roller 64 to form a nip. The original bundle on the original tray 50 is fed from the uppermost sheet by the feeding roller 53, and is separated and conveyed one by one to the feeding path 86 by the separation conveyance roller 55 and the separation pad 56 (separation operation: SS2).
[0039]
After the document P that has passed through the separating section is abutted against the registration roller pair 57 and skewing is corrected, the registration roller pair 57 is conveyed to the large roller 58 via the conveyance path 87 in synchronization with the large roller 58. When sandwiched between the large roller 58 and the pressure roller A59, the driving of the registration roller pair 57 is cut off and conveyed only by the large roller 58. The registration roller pair 57 is driven by a one-way gear (not shown), and is driven to rotate by the original P even when the drive is cut off (feed operation: SS3).
[0040]
The document P is conveyed along the large roller 58 and is conveyed from the reverse path 88 to the reading path 89. The leading edge of the document P passes through the read sensor 80, and reading of an image is started at the timing when the leading edge of the document reaches the image reading unit 45 based on the detection signal. The original P enters the discharge path 90 while the image is read. FIG. 6 shows a state during image reading (image reading operation: SS4). When the image reading is completed, it is determined whether or not it is the final document (SS5). If there is a next document, the document P is discharged onto the discharge tray 67 by the discharge roller 64 and stacked (discharge operation: SS8). The separation operation and feeding operation are performed in the same way (SS2 to SS5). Here, when there is a next document, the separation operation (SS2) may be performed on the next document during image reading, and the feeding operation (SS3) may be waited. If the document is final (SS5), the discharge solenoid (73) is turned OFF (SS7) after the discharge operation (SS6), and the discharge roller 65 is separated from the discharge roller 64.
[0041]
Thus, in the small size single-sided mode, once the discharge solenoid 73 is turned on, it is not turned off until all the documents are discharged. For this reason, it has been possible to suppress the ON / OFF operation of the discharge solenoid 73 every time a document is discharged, but only one ON / OFF operation when processing a plurality of documents. The operating noise can be reduced. In the above operation, the discharge solenoid 73 may be turned on (SS1) after image reading (SS4) of the first document, and turned off after all the documents are ejected.
[0042]
The large size single-sided mode (M9) will be described with reference to the flowcharts of FIGS. In this case as well, the separation operation (LS1), feeding operation (LS2), and image reading operation (LS3) are performed in the same manner as described above, but the discharge solenoid 73 is turned ON (LS4) after the image reading is completed, and then the discharge tray It differs in that it discharges to 67. Specifically, it is determined whether or not the document is the final document after the discharge solenoid is turned on (LS4) (LS5). If there is a next document, the discharge solenoid 73 is turned off after the discharge operation (LS8) (LS9). In preparation for the next image reading. In the case of the final document, the discharge solenoid (LS6) is turned off after the discharge operation (LS6) is performed (LS7), and the series of image reading operations is completed.
[0043]
That is, as shown in FIG. 7, the discharge roller 65 is separated from the discharge roller 64 during image reading. Since the discharge roller 64 is different in driving source from the large roller 58, a slight difference in peripheral speed occurs. In addition, since the transport distance is long in the large size, if the discharge roller 65 is constantly pressurized, there is a problem that the document is bent or stretched between the large roller 58 and the discharge roller 64 during transport due to the difference in peripheral speed. Resulting in. For this reason, in a large-size document, it is necessary to separate the discharge roller 65 during image reading so as to eliminate the influence. As in the conventional case, one pressurization for discharging each document and one separation after discharging are performed. It is necessary to operate twice.
[0044]
The small size double-side mode (M6) will be described with reference to the flowcharts of FIGS. First, the discharge solenoid 73 is turned on (SD1) and the discharge roller 65 is pressed against the discharge roller 64 to form a nip. In the same manner as described above, the separation operation (SD2), the feeding operation (SD3), and the image reading operation (SD4) are performed. As shown in FIG. 8, the original P passes through the nip between the discharge roller 64 and the discharge roller 65 along with the image reading, and enters the discharge tray 67.
[0045]
When the trailing edge of the document passes through the deflection guide 63 and is detected by the discharge sensor 81, the discharge roller 64 temporarily stops rotating based on this detection signal, and rotates in the reverse direction to reverse the document in the switchback direction. (Switchback operation: SD5). Then, as shown in FIG. 9, the document enters the switchback path 91 and is fed again to the large roller 58 (refeed operation: SD6). Then, image reading is performed on the back side while conveying the document again (back side reading operation: SD7).
[0046]
When the image reading operation on the back side is completed, the switchback operation (SD8) and the refeed operation (SD9) are performed again to determine whether or not the document is the final document (SD10). Are discharged and stacked on the discharge tray 67 by the discharge roller 64 (discharge operation: SD13), and then the separation operation and the feeding operation are sequentially performed in the same manner (SD2 to SD10). When the document is final, after the discharge operation (SD11) is performed, the discharge solenoid 73 is turned off (SD12), and the discharge roller 65 is separated from the discharge roller 64. Note that the second switchback is an idling conveyance performed in order to adjust the page order of the documents stacked on the discharge tray 513 without performing the image reading operation.
[0047]
As described above, in the small size double-side mode, once the discharge solenoid 73 is turned on, it is not turned off until all documents are discharged. For this reason, it has been possible to suppress the ON / OFF operation of the discharge solenoid 73 every time a document is discharged, but only one ON / OFF operation when processing a plurality of documents. The operating noise can be reduced. In the above operation, the discharge solenoid 73 may be turned on (SD1) after image reading (SD4) of the first document, and turned off after all the documents are ejected.
[0048]
The large size double-sided mode (M10) will be described with reference to the flowcharts of FIGS. 10, 11, and 16. FIG. In the same manner as described above, the separation operation (LD1), the feeding operation (LD2), and the image reading operation (LD3) are performed. Then, as shown in FIG. 10, when the trailing edge of the document is detected by the discharge sensor 81, the discharge solenoid 73 is turned on (LD4) to clamp the document, and the discharge roller 64 is reversed to perform the switchback operation (LD5). I do.
[0049]
Further, when the document is sandwiched between the pressure rollers A59, the discharge solenoid 73 is turned off (LD6), the refeed operation (LD7) is performed, and the image is read on the back side of the document (LD8). At this time, in the case of a large-size document, the document passes by the discharge roller 64 as shown in FIG. 11, but the passing operation can be smoothly performed by turning off the discharge solenoid 73.
[0050]
When the back side image reading operation is completed, the discharge solenoid 73 is turned on (LD9), the switchback operation (LD10) is performed again, the discharge solenoid 73 is turned off (LD11), and the refeed operation is performed again (LD12). I do. This re-feeding operation is an idling conveyance performed in order to adjust the page order of the originals stacked on the discharge tray 513. Then, after the discharge solenoid 73 is turned on (LD13), it is determined whether or not it is the last document (LD14). If there is a next document, the discharge solenoid 73 is turned off after the discharge operation (LD17) (LD18). In preparation for the next image reading. In the case of the final document, the discharge solenoid 73 is turned off after performing the discharge operation (LD15) (LD16), and the series of image reading operations is completed.
[0051]
When a large-size document is conveyed in this way, the conveyance error is caused by the fact that the document passes by the discharge roller 64 as shown in FIG. 11 and the peripheral speed difference between the large roller 58 and the discharge roller 64 as described above. Therefore, it is necessary to keep the discharge roller 65 apart except when discharging or switching back. For this reason, as in the prior art, one press for switching back per document, one separation for passing before reading the back side, and a second pressing for switching back again after reading the back side, for passing. It is necessary to operate a total of six times: the second separation, the third pressurization for discharge, and the third separation at the end of the job.
[0052]
In the above embodiment, the sheet conveying apparatus according to this embodiment is applied to the image input unit of the copying machine. However, the image reading apparatus such as a scanner or a facsimile, and the image forming apparatus using an ink jet system or an electrophotographic system. It is also possible to apply to.
[0053]
【The invention's effect】
As described above, in the present invention, a sheet having a discharge reversing unit that rotates forward and backward to the downstream side of the conveying unit that conveys the sheet to the image reading unit or the image forming unit and re-feeds the sheet to the conveying unit. In the conveying apparatus, when the length of the sheet in the conveyance direction is shorter than a predetermined value, the sheet holding unit is always pressed against the discharge reversing unit, so that the length of the sheet in the conveyance direction is shorter than the predetermined value. The number of operations of the sheet clamping means can be remarkably reduced, and the operating noise of the apparatus can be reduced.
[0054]
In particular, by setting the predetermined value to the size of a frequently used sheet, the frequency at which the effect of reducing operating noise can be obtained is increased.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a sheet conveying apparatus according to an embodiment.
FIG. 2 is a diagram illustrating a configuration of an image processing apparatus according to the present embodiment.
FIG. 3 is a diagram illustrating a drive system of the sheet conveying apparatus.
FIG. 4 is a diagram for explaining a configuration of a discharge portion.
FIG. 5 is a block diagram illustrating a circuit configuration of a control device.
FIG. 6 is a diagram illustrating a document reading operation in a small size single-sided mode.
FIG. 7 is a diagram illustrating a document reading operation in a large size single-sided mode.
FIG. 8 is a diagram for explaining a document reading operation in a small size double-side mode.
FIG. 9 is a diagram illustrating a document reading operation in a small size double-side mode.
FIG. 10 is a diagram for explaining a document reading operation in a large size double-side mode.
FIG. 11 is a diagram illustrating a document reading operation in a large size double-side mode.
FIG. 12 is a flowchart illustrating image reading mode selection.
FIG. 13 is a flowchart illustrating an original reading operation in a small size single-sided mode.
FIG. 14 is a flowchart illustrating an original reading operation in a large size single-sided mode.
FIG. 15 is a flowchart illustrating an original reading operation in a small size double-side mode.
FIG. 16 is a flowchart for explaining a document reading operation in a large size double-side mode.
FIG. 17 is a diagram illustrating a conventional sheet conveying apparatus.
[Explanation of symbols]
P: Manuscript
1 ... Image input part
2 Image output unit
3 ... Post-processing device
3a ... Non-sort tray
3b ... Sort bin tray
3c ... Non-sort tray discharge roller
3d ... sort bin tray discharge roller
4 ... Re-transport path
5 ... ADF
10… Upper cassette
11… Lower cassette
12… deck
13 ... Feed roller
14… Bypass guide
15… Registration roller pair
16… Photosensitive drum
17… Primary charging means
18… Developing means
19… Transfer charger
20… Separate charger
21… cleaner
22… Conveyor belt
23… Fixer
24… Diverter
25… Conveying roller
26… Intermediate tray
27… Conveyor belt
28… Diverter
29… Conveyor belt
30 ... Reverse path
31… discharge roller
32… Half Moon Roller
33… Half Moon Roller
34… Separation roller pair
35… Conveying roller
36… Sinking platen
37… Book Platen
38… Scanner unit
39… Ramp
40 Mirror
41 Mirror
42 Mirror
43… Lens
44… Image sensor
45 Image reading unit
46… Jump stand
50 ... Document tray
51… Width direction regulating plate
52… Stopper
53… feed roller
54… Arm
55… Separation transport roller
56… Separation pad
57… Registration roller pair
58… Large roller
59… Pressure roller A
60… Pressure roller B
61… Pressure roller C
62 ... White plate
63 ... Deflection guide
64… Retraction roller
65… Exhaust roller
67… discharge tray
68… Solenoid solenoid
69… Tension spring
70… separation motor
71… Lead motor
72… Waste motor
73… Exhaust solenoid
73a… Plunger
73b Stopper
73c ... Housing
74 Link
74a ... center
75… Tension spring
76… Tray sensor
77… Width detection sensor
78 ... Document stacking detection sensor
79… Separate sensor
80… Lead sensor
81… discharge sensor
82 ... CPU
83 ... RAM
84… ROM
85 ... IC
86… Feeding pass
87… Conveyance path
88… Reverse path
89… Reading path
90… discharge path
91… Switchback path

Claims (6)

A conveying unit that conveys the sheet to the image reading unit or the image forming unit;
A discharge reversing unit disposed downstream of the conveying unit and rotating forward and reverse to discharge the sheet or refeed the sheet;
A sheet clamping means that is capable of being pressed and spaced apart from the discharge reversing means;
Size detection means for detecting the length in the conveyance direction of the sheet,
In the mode in which the sheet is re-fed by the discharge reversing unit, at least the length of the sheet in the conveying direction is the same as that of the leading edge of the sheet and the rear of the sheet when the sheet is re-fed. In the case where the end portions pass each other, the discharge reversing unit pressurizes the sheet clamping unit to convey the sheet in the discharge direction by the discharge reversing unit and the sheet clamping unit, and then re-feeds the sheet. After the sheet is conveyed by the discharge reversing means and the sheet sandwiching means, the sheet sandwiching means is separated from the discharge reversing means, and the leading end of the sheet conveyed in the refeeding direction becomes the discharge reversing means. After reaching and after the trailing edge of the sheet has passed through the discharge reversing means, the discharge reversing means pressurizes the sheet clamping means, and the discharge reversing means and the sheet clamping means Conveying the door,
In the mode in which the sheet is re-fed by the discharge reversing unit, the length of the sheet in the conveying direction is such that when the sheet is re-fed, the leading end and the rear end of one sheet pass in the discharge reversing unit. When the length is not different, the sheet clamping means is not separated from the discharge reversing means during sheet conveyance,
In a mode in which the sheet is discharged without being re-fed by the discharge reversing unit, when the length of the sheet detected by the size detecting unit is a predetermined value or more, the sheet holding unit is separated from the discharge reversing unit. The discharge reversing means presses the sheet holding means so as to hold the sheet conveyed in the state, and after discharging the sheet, the sheet holding means is separated from the discharge reversing means, and is detected by the size detection means. When the length of the sheet is shorter than a predetermined value, the sheet nipping unit always pressurizes the discharge reversing unit during sheet conveyance. A conveying unit that conveys the sheet to the image reading unit or the image forming unit;
A discharge reversing unit disposed downstream of the conveying unit and rotating forward and reverse to discharge the sheet or refeed the sheet;
A sheet clamping means that is capable of being pressed and spaced apart from the discharge reversing means;
Input means for inputting a length in the conveyance direction of the sheet,
In the mode in which the sheet is re-fed by the discharge reversing unit, at least the length of the sheet in the conveying direction is the same as that of the leading edge of the sheet and the rear of the sheet when the sheet is re-fed. In the case where the end portions pass each other, the discharge reversing unit pressurizes the sheet clamping unit to convey the sheet in the discharge direction by the discharge reversing unit and the sheet clamping unit, and then re-feeds the sheet. After the sheet is conveyed by the discharge reversing means and the sheet sandwiching means, the sheet sandwiching means is separated from the discharge reversing means, and the leading end of the sheet conveyed in the refeeding direction becomes the discharge reversing means. After reaching and after the trailing edge of the sheet has passed through the discharge reversing means, the discharge reversing means pressurizes the sheet clamping means, and the discharge reversing means and the sheet clamping means Conveying the door,
In the mode in which the sheet is re-fed by the discharge reversing unit, the length of the sheet in the conveying direction is such that when the sheet is re-fed, the leading end and the rear end of one sheet pass in the discharge reversing unit. When the length is not different, the sheet clamping means is not separated from the discharge reversing means during sheet conveyance,
In a mode in which the sheet is discharged without being re-fed by the discharge reversing unit, when the length of the sheet input by the input unit is a predetermined value or more, the sheet holding unit is separated from the discharge reversing unit The sheet reversing unit pressurizes the sheet nipping unit so as to nipping the sheet conveyed by the sheet, and after discharging the sheet, the sheet nipping unit is separated from the discharge reversing unit, and the sheet input by the input unit When the length of the sheet is shorter than a predetermined value, the sheet nipping means always pressurizes the discharge reversing means during sheet conveyance. An image processing apparatus comprising: the sheet conveying apparatus according to claim 1 ; and an image reading unit that reads an image of the sheet. In the mode in which the sheet is discharged without being re-fed by the discharge reversing unit, when the length of the sheet detected by the size detection unit is equal to or greater than the predetermined value, the image reading unit reads the sheet image. Sometimes, the sheet holding means is separated from the discharge reversing means, and after the reading of the image of the sheet by the image reading means is finished, the sheet holding means is pressed against the discharge reversing means to discharge the sheet. The image processing apparatus according to claim 3. An image processing apparatus comprising: the sheet conveying apparatus according to claim 2; and an image reading unit that reads an image of the sheet. In a mode in which the sheet is discharged without being re-fed by the discharge reversing unit, when the length of the sheet input by the input unit is equal to or greater than the predetermined value, and when the image of the sheet is read by the image reading unit The sheet holding means is separated from the discharge reversing means, and after the reading of the image of the sheet by the image reading means is completed, the sheet holding means is pressed against the discharge reversing means to discharge the sheet. The image processing apparatus according to claim 5.

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