JP2008189447A - Sheet conveying apparatus and sheet processing apparatus provided with the same - Google Patents

Abstract

To provide a sheet conveying apparatus and a sheet processing apparatus capable of suppressing the occurrence of a sheet conveyance failure related to a special sheet without providing a new conveyance path.
A sheet conveyance mechanism includes a conveyance roller 220, a shape information acquisition unit 350, and a CPU 300. The conveyance roller 220 includes a plurality of driven rollers 222 </ b> A to 222 </ b> C that apply a conveyance force to the sheet at mutually different positions in the width direction orthogonal to the sheet conveyance direction. The shape information acquisition unit 350 acquires the shape information of the sheet conveyed by the conveyance roller 220. The CPU 300 sets the force acting on the sheet from the driven rollers 222A to 222C in the conveyance roller 220 based on the sheet shape information acquired by the shape information acquisition unit 350, respectively.
[Selection] Figure 4

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and a sheet processing apparatus including the sheet conveying apparatus.

  Many sheet conveying apparatuses used in scanners, printers, copiers and the like include an automatic conveyance mechanism and a manual conveyance mechanism. The automatic conveyance mechanism automatically and sequentially supplies a plurality of regular sheets stored in the sheet storage unit to the sheet processing unit. The manual feed mechanism supplies an irregular sheet such as cardboard or tab paper to the sheet processing unit. By using this manual feed mechanism, it is possible to process more types of sheets.

Further, some conventional sheet conveying apparatuses are capable of conveying a recording medium such as a CD-R. For example, in the prior art, there is a sheet conveyance mechanism that enables the conveyance of a CD-R while appropriately conveying the sheet (see, for example, Patent Document 1). In a recording apparatus adopting this sheet conveying mechanism, a notch corresponding to the width of the CD-R tray is provided in the switching flapper in order to secure a conveyance path for CD-R. By such a device, it is possible to appropriately perform sheet feeding by the automatic sheet feeding mechanism, sheet feeding from the manual feed tray, and CD-R transport and supply.
JP 2006-110938 A

  In recent years, the types of sheets conveyed by the manual conveyance mechanism are increasing. As the number of types of conveyed sheets increases, the risk of sheet conveyance failure increases, and countermeasures against this need to be taken. For example, when a part of the sheet is configured to have a thickness different from that of the other part, it is necessary to prevent the sheet conveyance failure from occurring due to the part having the different thickness.

  From the viewpoint of preventing occurrence of sheet conveyance failure, it is possible to provide a dedicated conveyance path for a special sheet having a special shape, as the recording apparatus according to Patent Document 1 separately provides a CD-R conveyance path. This is desirable.

  However, it is almost impossible to predict all the shapes of special sheets that are considered to be conveyed in the future by the manual conveyance mechanism. Even if it can be predicted, it is not practical to provide a dedicated conveyance path for every predicted special sheet.

  An object of the present invention is to provide a sheet conveying apparatus and a sheet processing apparatus capable of suppressing the occurrence of a sheet conveyance defect related to a special sheet without providing a new conveyance path.

  The sheet conveying apparatus according to the present invention includes conveying means, shape information acquiring means, and conveying control means. The conveying unit includes a plurality of conveying units that apply a conveying force to the sheet at different positions in the width direction orthogonal to the sheet conveying direction. A representative example of the conveying means is a plurality of conveying rollers arranged in the width direction.

  The shape information acquisition unit is configured to acquire shape information of the sheet conveyed by the conveyance unit. As an example of the sheet shape information, there is information indicating the position of the first portion having a uniform thickness in the sheet and the position of the second portion having a thickness different from that of the first portion. Further, as an example of a method for acquiring sheet shape information, acquiring sheet shape information based on an image of a sheet read by a scanner can be cited. Other examples of the acquisition method include accepting input of sheet shape information by the user, and providing a sensor for detecting the shape of the sheet before or during conveyance, and acquiring the sheet shape information from this sensor. It is done.

  The conveyance control unit controls the force acting on the sheet from each conveyance unit in the conveyance unit based on the sheet shape information acquired by the shape information acquisition unit. Examples of techniques for controlling the force acting on the sheet from each conveyance unit include setting a contact force between each conveyance unit and the sheet, or preventing any conveyance unit from contacting the sheet. .

  With the above-described configuration, it is possible to apply an optimum conveying force to different positions in the width direction on the sheet. As a result, even when a cut-out hole or notch is formed, or even when a surface coating or a seal is applied to a part of the sheet, the conveying force acting on the processed part is appropriately adjusted. it can.

  Furthermore, the above-described technical idea can be applied to movement control of a sheet detection sensor configured to be movable in the width direction for detecting a sheet. For example, on the basis of the sheet shape information acquired by the shape information acquisition unit, the sheet detection sensor may be moved so as to avoid a portion processed so as to have a different thickness from other portions. As a result, it is possible for the sheet detection sensor to collide with a portion that is processed to have a thickness different from other portions, or to detect a notch portion in the sheet, thereby causing erroneous detection of the sheet conveyance timing. Become.

  According to the present invention, it is possible to suppress the occurrence of sheet conveyance failure related to a special sheet without providing a new conveyance path.

  FIG. 1 is a schematic diagram illustrating an overall configuration of an image forming apparatus to which an embodiment of a sheet conveying apparatus of the present invention is applied. As will be described in detail later, the sheet conveying apparatus of the present embodiment is applied to a document conveying unit (ADF) 101 of an image forming apparatus, and a plurality of documents placed on a document tray 11 are reliably received at regular intervals. Pull out and transport.

  The image forming apparatus 100 acquires image data read from a document, or acquires image data received from the outside, and forms a monochrome image indicated by the image data on a recording sheet. Are roughly divided into a document conveying unit (ADF) 101, an image reading unit 102, a printing unit 103, a recording paper conveying unit 104, and a paper feeding unit 105.

  When at least one document is set on the document tray 11 in the document conveying unit 101, the document is pulled out and conveyed one by one from the document tray 11, and the document is guided to the document reading window 102 </ b> A of the image reading unit 102. The original is discharged and discharged to the paper discharge tray 12.

  A CIS (Contact Image Sensor) 13 is disposed above the document reading window 102A. When the document passes through the document reading window 102A, the CIS 13 repeatedly reads the image on the back side of the document in the main scanning direction and outputs image data indicating the image on the back side of the document.

  The details of the document conveying unit 101 will be described later with reference to FIG.

  Further, the image reading unit 102 exposes the document surface by the lamp of the first scanning unit 15 when the document passes through the document reading window 102A, and the mirror of the first and second scanning units 15 and 16 from the document surface. The reflected light is guided to the imaging lens 17, and an image of the document surface is formed on a CCD (Charge Coupled Device) 18 by the imaging lens 17. The CCD 18 repeatedly reads an image on the document surface in the main scanning direction and outputs image data indicating the image on the document surface.

  Further, when the document is placed on the platen glass on the upper surface of the image reading unit 102, the first and second scanning units 15 and 16 are moved while maintaining a predetermined speed relationship with each other. The document surface on the platen glass is exposed, the reflected light from the document surface is guided to the imaging lens 17 by the first and second scanning units 15 and 16, and the image on the document surface is connected to the CCD 18 by the imaging lens 17. Image.

  The image data output from the CIS 13 or the CCD 18 is subjected to various image processing by a control circuit such as a microcomputer and then output to the printing unit 103.

  The printing unit 103 records a document indicated by image data on a sheet, and includes a photosensitive drum 21, a charger 22, an optical writing unit 23, a developing unit 24, a transfer unit 25, a cleaning unit 26, and a fixing unit. 27 etc.

  The photosensitive drum 21 rotates in one direction, and after the surface is cleaned by the cleaning unit 26, the surface is uniformly charged by the charger 22. The charger 22 may be of a charger type or of a roller type or a brush type that contacts the photosensitive drum 21.

  The optical writing unit 23 is a laser scanning unit (LSU) including two laser irradiation units 28A and 28B and two mirror groups 29A and 29B. In this optical writing unit 23, image data is input, laser light corresponding to this image data is emitted from each laser irradiation section 28A, 28B, and these laser lights are respectively passed through mirror groups 29A, 29B. The drum 21 is irradiated to expose the uniformly charged surface of the photosensitive drum 21 to form an electrostatic latent image on the surface of the photosensitive drum 21.

  The optical writing unit 23 employs a two-beam system including two laser irradiation units 28A and 28B in order to cope with high-speed printing processing, thereby reducing the burden associated with increasing the irradiation timing.

  As the optical writing unit 23, an EL writing head or an LED writing head in which light emitting elements are arranged in an array can be used instead of the laser scanning unit.

  The developing device 24 supplies toner to the surface of the photosensitive drum 21 to develop the electrostatic latent image, and forms a toner image on the surface of the photosensitive drum 21. The transfer unit 25 transfers the toner image on the surface of the photosensitive drum 21 onto the recording paper conveyed by the paper conveyance unit 104. The fixing unit 27 heats and pressurizes the recording paper to fix the toner image on the recording paper. Thereafter, the recording sheet is further conveyed to the sheet discharge tray 47 by the sheet conveying unit 104 and discharged. The cleaning unit 26 removes and collects the toner remaining on the surface of the photosensitive drum 21 after development and transfer.

  Here, the transfer unit 25 includes a transfer belt 31, a drive roller 32, a driven roller 33, an elastic conductive roller 34, and the like, and the transfer belt 31 is stretched between the rollers 32 to 34 and other rollers. Rotating. The transfer belt 31 has a predetermined resistance value (for example, 1 × 10 9 to 1 × 10 13 Ω / cm), and conveys the recording paper placed on the surface thereof. The elastic conductive roller 34 is pressed against the surface of the photosensitive drum 21 via the transfer belt 31, and presses the recording paper on the transfer belt 31 against the surface of the photosensitive drum 21. An electric field having a polarity opposite to the charge of the toner image on the surface of the photosensitive drum 21 is applied to the elastic conductive roller 34, and the toner image on the surface of the photosensitive drum 21 is transferred onto the transfer belt 31 by the electric field having the opposite polarity. Is transferred onto the recording paper. For example, when the toner image has a charge of (−) polarity, the polarity of the electric field applied to the elastic conductive roller 34 is set to (+) polarity.

  The fixing unit 27 includes a heating roller 35 and a pressure roller 36. A heat source for setting the surface of the heating roller 35 to a predetermined temperature (fixing temperature: approximately 160 to 200 ° C.) is provided inside the heating roller 35. In addition, pressure members (not shown) are arranged at both ends of the pressure roller 36 so that the pressure roller 36 is pressed against the heating roller 35 with a predetermined pressure. When the recording paper is conveyed to a pressure contact portion (referred to as a fixing nip portion) between the heating roller 35 and the pressure roller 36, the recording paper is conveyed by the rollers 35 and 36 and is not fixed on the recording paper. The toner image is heated and melted and pressed to fix the toner image on the recording paper.

  The paper transport unit 104 includes a plurality of pairs of transport rollers 41, a pair of registration rollers 42, a transport path 43, a reverse transport path 44, a plurality of branching claws 45, a pair of paper discharge rollers 46, and the like for transporting recording paper. I have.

  In the conveyance path 43, the recording paper is received from the paper supply unit 105, and the recording paper is conveyed until the leading edge of the recording paper reaches the registration roller 42. At this time, since the registration roller 42 is temporarily stopped, the leading edge of the recording paper reaches and contacts the registration roller 42, and the recording paper is bent. The leading edge of the recording sheet is aligned parallel to the registration roller 42 by the elastic force of the bent recording sheet. Thereafter, the rotation of the registration roller 42 is started, the recording paper is conveyed to the transfer unit 25 of the printing unit 103 by the registration roller 42, and the recording paper is further conveyed to the paper discharge tray 47 by the paper discharge roller 46.

  The registration roller 42 is stopped and rotated by switching on and off the clutch between the registration roller 42 and the drive shaft, or by switching on and off the motor that is the drive source of the registration roller 42.

  When recording an image on the back side of the recording paper, the plurality of branching claws 45 are rotated to switch the branch path between the transport path 43 and the reverse transport path 44, and the reverse side of the recording paper is reversed by the reverse transport path 44. After that, the recording sheet is returned to the registration roller 42 in the conveyance path 43 through the reverse conveyance path 44. As a result, an image is also recorded on the back surface of the recording paper.

  In the transport path 43 and the reverse transport path 44, sensors for detecting the position of the recording paper and the like are arranged in various places, and the transport roller and the registration roller are driven and controlled based on the position of the recording paper detected by each sensor. The recording paper is conveyed and positioned.

  The paper feed unit 105 includes a plurality of paper feed cassettes 51. Each paper feed cassette 51 is for storing recording paper, and is provided below the image forming apparatus 100. Each paper feed cassette 51 includes a pickup roller or the like for pulling out the recording sheets one by one, and sends out the pulled recording sheets to the transport path 43 of the sheet transport unit 104.

  Since the image forming apparatus 100 of the present embodiment is intended for high-speed printing processing, each paper feed cassette 51 has a capacity capable of storing 500 to 1500 standard size recording sheets.

  Further, on the side surface of the image forming apparatus 100, a large-capacity paper feed cassette (LCC) 52 capable of storing a large amount of a plurality of types of recording papers and a manual feed tray 53 for mainly supplying irregular-size recording papers are provided. ing.

  The paper discharge tray 47 is disposed on the side surface opposite to the manual feed tray 53. In place of the paper discharge tray 47, a post-processing device for paper discharge (such as stapling and punching) and a plurality of paper discharge trays can be arranged as options.

  Next, the document conveying unit 101 to which the sheet conveying apparatus of this embodiment is applied will be described. FIG. 2 is a schematic diagram illustrating the configuration of the document conveying unit 101. FIG. 3 is a side view showing the vicinity of the pickup roller 61 in the document conveying unit 101.

  As shown in FIG. 2, the document transport unit 101 separates the document tray 11 on which the document bundle is placed, the pickup roller 61 that pulls out the document from the document tray 11, and the document that has been sent out one by one. The paper feeding roller 62 and the separating roller 63 for conveying the original to the original conveying path S1, the plural pairs of conveying rollers 64 for conveying the original along the paper conveying path S1, and the original to the original reading window 102A at a predetermined timing. A pair of registration rollers 65 for feeding the paper, a pair of paper discharge rollers 66 for discharging the document whose image has been read to the paper discharge tray 12, and a CIS 13 which is disposed above the document reading window 102A and reads the image on the back side of the document. And is composed mainly of.

  As shown in FIG. 3, the pickup roller 61 is supported so as to be rotatable around the drive shaft of the paper feed roller 62, and is rotated downward around the drive shaft of the paper feed roller 62 to The document is pressed against the uppermost document in the document bundle or rotated upward and separated from the document tray 11. The rotational movement of the pickup 61 is performed by a motor and a power transmission mechanism (not shown).

  In the standby state, the pickup roller 61 is rotated upward and separated from the document tray 11.

  When the user requests printing and a paper sensor (not shown) on the document tray 11 detects the document, the pickup roller 61 is rotated downward and pressed against the uppermost document on the document tray 11. In this state, the pickup roller 61 sends the document bundle from the uppermost document to the sheet conveyance path S1.

  The drive shaft of the paper feed roller 62 is rotationally driven by a motor and a power transmission mechanism (not shown), the paper feed roller 62 is rotationally driven, and the separating roller 63 pressed against the paper feed roller 62 is driven to rotate. To do.

  An endless belt 75 is stretched between the pulley 73 on the pickup roller 61 side and the pulley 74 on the paper feed roller 62 side, and a clutch 76 is interposed between the shaft of the pickup roller 61 and the pulley 73. A drive shaft 62 and a pulley 74 are directly connected and fixed.

  When the paper feed roller 62 is driven to rotate, the pulley 74 fixed to the drive shaft of the paper feed roller 62 rotates, and the rotation of the pulley 74 is transmitted to the pulley 73 on the pickup roller 61 side through the endless belt 75. Thus, the pulley 73 is rotationally driven. At this time, when the shaft of the pickup roller 61 and the pulley 73 are connected via the clutch 76, the pickup roller 61 rotates together with the pulley 73, and when the shaft of the pickup roller 61 and the pulley 73 are disconnected, only the pulley 73 is provided. Rotates, the rotational driving force of the pulley 73 is not transmitted to the pickup roller 61, and the pickup roller 61 becomes rotatable.

  Here, when the pickup roller 61 is pressed against the uppermost document of the document bundle on the document tray 11, the paper feed roller 62 is driven to rotate, and the clutch 76 is controlled to contact and the pickup roller 61 is driven to rotate. The pickup roller 61 pulls out the uppermost document, and the leading edge of the document is conveyed and guided between the paper feeding roller 62 and the separating roller 63, and the document is further fed out to the paper conveying path S1 by the paper feeding roller 62. .

  Then, after the leading edge of the uppermost document passes between the paper feed roller 62 and the separating roller 63, the clutch 76 is controlled to be disengaged so that the pickup roller 61 is rotatable. 62 is driven to rotate on the uppermost document conveyed by 62.

  Further, when the rear end of the uppermost document passes through the portion of the pickup roller 61, the pickup roller 61 is placed on the next document below the uppermost document, and the next document is stationary. The rotation of the roller 61 stops. For this reason, the uppermost original and the next original are not continuously drawn out and conveyed by the pickup roller 61, and two originals are not double-fed.

  When the trailing edge of the uppermost document passes between the paper feed roller 62 and the separating roller 63, the clutch 76 is controlled to rotate, the pickup roller 61 is driven to rotate, and the drawing of the document by the pickup roller 61 is resumed. As a result, the pickup roller 61 pulls out the next original, and the leading end of the original is conveyed and guided between the paper feeding roller 62 and the separating roller 63, and the original is further guided to the paper conveying path S1 by the paper feeding roller 62. Sent out.

  Thereafter, similarly, the contact control and disconnection control of the clutch 76 are performed, and the documents on the document tray 11 are intermittently pulled out one by one by the pickup roller 61 and conveyed to the sheet conveyance path S1.

  In the paper conveyance path S1, the original is conveyed while the registration roller 65 is temporarily stopped until the leading edge of the original contacts the registration roller 65, and the original is bent. Then, after the leading edge of the original is aligned parallel to the registration roller 65 due to the elastic force of the bent original, the registration roller 65 starts to rotate, and the original is re-conveyed by the registration roller 65. The paper is guided to the original reading window 102A of the image reading unit 102 and passed, and the original is discharged to the paper discharge tray 12 by the paper discharge roller 66.

  The registration roller 65 is stopped and rotated by switching on and off the clutch between the registration roller 65 and the drive shaft, or by switching on and off the motor that is the drive source of the registration roller 65.

  FIG. 3A to FIG. 3C show configuration examples of special sheets. The special sheet shown in FIG. 3A includes a base portion 210 formed to have a uniform thickness, and a coating portion 212 attached to the base portion 210. The special sheet shown in FIG. 3B includes a base portion 210 and a window portion 214 formed in the base portion 210. The special sheet shown in FIG. 3C includes a base portion 210 and a slit 216 formed in the base portion 210. In this embodiment, the base part 210 constitutes the first part of the present invention. Moreover, the coating part 212, the window part 214, and the slit 216 each comprise the 2nd part of this invention.

  FIG. 4 shows a schematic configuration of the sheet conveying mechanism according to the present embodiment. This sheet transport mechanism can be applied to transport of recording paper fed from the manual feed tray 53 and transport of original fed from the document tray 11.

  The sheet conveyance mechanism includes a conveyance roller 220 corresponding to the conveyance unit of the present invention. The conveying roller 220 includes a driving roller 224 and a plurality of driven rollers 222A to 222C facing the driving roller. The driven rollers 222 </ b> A to 222 </ b> C apply a conveying force to the sheet at different positions in the width direction orthogonal to the sheet conveying direction. In this embodiment, each of the driven rollers 222A to 222C corresponds to the transport unit of the present invention.

  Each of the driven rollers 222 </ b> A to 222 </ b> C is movably supported by the roller support portion 250. The roller support portion 250 is configured so that the positions of the driven rollers 222A to 222C can be set separately.

  The configuration of the roller support mechanism 250 will be described with reference to FIG. Here, the portion of the roller support mechanism 250 that supports the driven roller 222A will be described as a representative, and the description of the portions that support the driven rollers 222B and 222C will be omitted.

  As shown in FIG. 5, the driven roller 222 </ b> A has a bearing 252 attached to its shaft. The bearing 252 is passed through the long hole 255 and is disposed so that the end of the bearing 252 fits in the groove of the cam 254 that is rotatable. The cam 254 is connected to a drive unit (not shown) via a transmission mechanism including a bevel gear 256. The bearing 252 is applied with a force in the direction of the driving roller 224 by a spring 258. As the cam 254 rotates, the bearing moves through the long hole 255, and the driven roller 222A approaches or separates from the driving roller 224. Here, the driven roller 222A is moved using a groove cam mechanism, but a solenoid may be used instead of the groove cam mechanism.

  FIG. 6 is a block diagram showing an outline of the configuration of the sheet support mechanism. As shown in the figure, the sheet transport mechanism includes a roller support unit 250, a roller drive unit 280, a shape information acquisition unit 350, a ROM 302, a RAM 304, a display unit 306, an operation unit 308, and a CPU 300.

  The roller driving unit 280 drives the driving roller 224 and other driving rollers based on a signal from the CPU 300. The shape information acquisition unit 350 corresponds to the shape information acquisition unit of the present invention and is configured to acquire the shape information of the sheet conveyed by the conveyance roller 220.

  As an example of the sheet shape information, there is information indicating the position of the first portion having a uniform thickness in the sheet and the position of the second portion having a thickness different from that of the first portion. For example, as shown in FIG. 7A, information indicating which position the second part is included in may be used by dividing the sheet into nine parts. Further, as shown in FIG. 7B, the sheet can be divided into three in the width direction, and information indicating where the second portion is included can be used.

  In the present embodiment, the shape information acquisition unit 350 acquires sheet shape information based on the sheet image read by the image reading unit 102. However, the method of acquiring sheet shape information is not limited to this. For example, information related to the shape of the sheet from the user input via the operation unit 308 can be acquired. Further, the sheet shape information may be acquired based on a detection result of a line sensor provided in the conveyance path or an area sensor provided on the document tray 11 or the manual feed tray.

  The ROM 302 stores a plurality of programs necessary for the operation of the CPU 300. The RAM 304 temporarily holds data. The display unit 306 is configured to display information to be notified by the user. The operation unit 308 receives an input operation from the user. The CPU 300 controls each part of the sheet conveying mechanism.

  In the present embodiment, the CPU 300 corresponds to the transport control means of the present invention. The CPU 300 controls the force acting on the sheet from each of the driven rollers 222 </ b> A to 222 </ b> C in the conveyance roller 220 based on the sheet shape information acquired by the shape information acquisition unit 350. Specifically, the CPU 300 controls the roller support unit 250 to set the contact force between the driven rollers 222A to 222C and the sheet, or to move any of the driven rollers 222A to 222C from the sheet. Or leave them apart.

  8A and 8B show a state in which the driven roller 222A and the driving roller 224 are in contact with each other. When the CPU 300 controls the roller support portion 250 in this state, the driven roller 222A moves away from the drive roller 224 as shown in FIGS. 8C and 8D. By appropriately adjusting the distance between the driven roller 222A and the driving roller 224, the pressure contact force between them can be adjusted.

  FIG. 9 is a flowchart illustrating an operation procedure of the CPU 300 during the conveyance control process. The CPU 300 causes the image reading unit 102 to read the image of the sheet set by the user (S1). Subsequently, the CPU 300 acquires sheet shape information based on the read image of the image reading unit 102 (S2). Subsequently, the CPU 300 controls the roller support portion 250 and sets the positions of the driven rollers 222A to 222C (S3). When the setting of the positions of the driven rollers 222A to 222C is completed, the CPU 300 causes the display unit 306 to display READY (S4).

  The CPU 300 arranges the driven rollers 222A to 222C that apply the conveying force to the first portion of the sheet and the rollers that apply the conveying force to the second portion of the sheet at different positions. The reason is that different conveying forces act on the first portion and the second portion of the sheet. In the present embodiment, the CPU 300 controls the roller support portion 250 so that the conveyance force acting on the second portion of the sheet is smaller than the conveyance force acting on the first portion. However, the control method of the roller support portion 250 by the CPU 300 is not limited to this, and any method can be appropriately selected.

  With the above configuration, it is possible to apply an optimum conveying force to different positions in the width direction of the sheet. As a result, even when the special sheet is conveyed as shown in FIGS. 3A to 3C, the conveying force acting on the coating part 212, the window part 214, or the slit 216 is appropriately adjusted. This facilitates the proper conveyance of the sheet. That is, even when the special sheet is conveyed, problems such as oblique feeding, conveyance deviation, and jam are less likely to occur.

  Another example of the sheet conveying mechanism will be described with reference to FIGS. Here, movement control of the sheet detection sensor when a special sheet is conveyed will be described.

  As shown in FIG. 10, the sheet transport mechanism includes a sheet detection sensor 410 for detecting a sheet. The sheet detection sensor 410 is supported by a sheet support unit 420 described later so as to be movable in the width direction of the sheet.

  FIG. 11 shows a schematic configuration of a sheet support unit 420 that supports the sheet detection sensor 410. The sheet support unit 420 includes an endless belt 422 stretched around a plurality of rollers, and a rotation driving unit 424 that applies a rotational force to the endless belt 422. The sheet detection sensor 410 is attached to the endless belt 422 and moves in the width direction as the endless belt 422 rotates.

  FIG. 12 is a block diagram illustrating a schematic configuration of the sheet conveying mechanism. The same components as those in FIG. 6 are given the same reference numerals, and the description thereof is omitted. Here, the CPU 300 corresponds to the sensor control means of the present invention. Based on the sheet shape information acquired by the shape information acquisition unit 350, the CPU 300 moves the sheet detection sensor 410 so as to avoid the window 214 or the slit 216.

  As a result, even when special sheets are conveyed as shown in FIGS. 3A to 3C, the sheet detection sensor 410 collides with the coating part 212, the window part 214, or the slit. By detecting 216 and outputting a detection result indicating that there is no sheet, it is possible to erroneously detect the sheet conveyance timing.

  FIG. 13 is a flowchart illustrating an operation procedure of the CPU 300 during the conveyance control process. The CPU 300 causes the image reading unit 102 to read the image of the sheet set by the user (S11). Subsequently, the CPU 300 acquires sheet shape information based on the read image of the image reading unit 102 (S12). Subsequently, the CPU 300 controls the sensor support unit 420 and sets the position of the sheet detection sensor 410 (S13). When the setting of the position of the sheet detection sensor 410 is completed, the CPU 300 causes the display unit 306 to display READY (S14).

  In the above-described embodiment, a roller is cited as a member that applies a conveyance force to the sheet. However, the present invention can be properly implemented even when a conveyance belt is used instead of the roller.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

1 is a diagram illustrating a schematic configuration of an image forming apparatus. FIG. 3 is a diagram illustrating a configuration of a document conveying unit. It is a figure which shows the structural example of a special sheet. 1 shows a schematic configuration of a sheet conveying mechanism according to an embodiment. It is a figure which shows schematic structure of a roller support part. 6 is a block diagram illustrating a configuration example of a sheet conveying mechanism. FIG. It is a figure which shows the example of shape information. It is a figure which shows operation | movement of a roller support part. It is a flowchart which shows the operation | movement procedure of CPU at the time of a conveyance control process. It is a figure which shows the other example of a structure of a sheet conveyance mechanism. It is a figure which shows schematic structure of a sensor support part. It is a block diagram which shows the other example of a structure of a sheet conveyance mechanism. It is a flowchart which shows the operation | movement procedure of CPU at the time of a sensor movement control process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100- Image forming apparatus 101- Document conveyance part 220- Conveyance roller 250- Roller support part 222A-222C- Driven roller 300-CPU
350-shape information acquisition unit 450-sheet detection sensor

Claims (8)

A sheet conveying device for conveying a sheet,
A conveying unit having a plurality of conveying units that apply a conveying force to the sheet at different positions in the width direction orthogonal to the conveying direction of the sheet;
Shape information acquisition means for acquiring shape information of a sheet conveyed by the conveyance means;
Based on the shape information of the sheet acquired by the shape information acquisition unit, a conveyance control unit that controls the force acting on the sheet from each conveyance unit in the conveyance unit;
A sheet conveying apparatus comprising: The shape information acquisition means acquires a position of a first portion having a uniform thickness in the sheet and a second portion having a thickness different from the first portion,
The said conveyance control means controls the said conveyance means so that different conveyance force each acts on the said 1st part and the said 2nd part of a sheet | seat from each conveyance part, The Claim 1 characterized by the above-mentioned. Sheet transport device.   The conveyance control means controls the conveyance means so that a pressure contact force between the conveyance unit and the second part is smaller than a pressure contact force between the conveyance part and the first part. The sheet conveying apparatus according to claim 2.   The sheet conveyance apparatus according to claim 2, wherein the conveyance control unit separates a conveyance unit that contacts the second portion from the sheet.   The sheet conveying apparatus according to claim 1, wherein the conveying unit is a roller or a belt configured to apply a conveying force to the sheet. A sheet conveying device for conveying a sheet,
A sheet detection sensor for detecting a sheet configured to be movable in a width direction orthogonal to the sheet conveyance direction;
Shape information acquisition means for acquiring shape information of a sheet conveyed by the conveyance means;
Sensor control means for moving the sheet detection sensor based on the shape information of the sheet acquired by the shape information acquisition means;
A sheet conveying apparatus comprising: The shape information acquisition means acquires a position of a first portion having a uniform thickness in the sheet and a second portion having a thickness different from the first portion,
The sheet conveying apparatus according to claim 1, wherein the sensor control unit moves the sheet detection sensor so that the sheet detection sensor does not detect the second portion of the sheet. A sheet conveying device according to any one of claims 1 to 7,
An image reading unit that reads an image of a sheet conveyed by the sheet conveying device;
With
The shape information acquisition unit is configured to determine a position of a first portion having a uniform thickness on the sheet and a second portion having a thickness different from the first portion based on an image of the sheet read by the image reading unit. A sheet processing apparatus that acquires the sheet processing apparatus.

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