JP2019034808A - Sheet conveyance device, image reading device and image formation device - Google Patents

Abstract

To provide a sheet conveyance device capable of suppressing mis-detection due to adhesion of foreign matters to position detection means.SOLUTION: Provided is an automatic document conveyance device 310 that is a sheet conveyance device comprising: a pick-up roller 301 that is a transport member adding conveyance force to a document as a sheet; a filler 2 that is a movable member that moves when the conveyed document contacts; a light transmission sensor 4 that is position detection means for detecting a position of the filler 2; and a cushion 11 that functions as cleaning means for cleaning the fille 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus.

2. Description of the Related Art Conventionally, a sheet conveying apparatus is known that includes a conveying member that applies a conveying force to a sheet, a movable member that rotates when the conveyed sheet comes into contact, and a position detection unit that detects the position of the movable member. . In this type of sheet conveying apparatus, the presence or absence of a sheet at the detection position where the movable member is arranged is detected based on the detection result of the position detection means.
Patent Document 1 includes a light transmission type photosensor including a light emitting unit and a light receiving unit as position detection means, and whether or not the light emitted from the light emitting unit is blocked by an actuator that is a movable member, A configuration for detecting the presence or absence of a sheet at a detection position is described.

  In the conventional sheet conveying apparatus, foreign matter may adhere to the position detection unit, and erroneous detection of the presence or absence of a sheet may occur.

  In order to solve the above-described problems, the present invention provides a conveying member that imparts a conveying force to a sheet, a movable member that moves when the conveyed sheet contacts, and a position detection unit that detects the position of the movable member. The sheet conveying apparatus includes a cleaning unit that cleans the movable member.

  According to the present invention, there is an excellent effect that it is possible to suppress false detection caused by foreign matter adhering to the position detection means.

FIG. 3 is an enlarged cross-sectional view of the vicinity of a document detection mechanism in an automatic document feeder. 1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 3 is a cross-sectional view of the image reading apparatus. Sectional drawing of the upper part of an automatic document feeder. FIG. 3 is a perspective sectional view of the vicinity of a document detection mechanism in the automatic document feeder. Sectional drawing of the upper part of the automatic document feeder of the state which the filler rotated. 1 is a schematic explanatory diagram of an image reading apparatus in a state before a document is set. FIG. 1 is a schematic explanatory diagram of an image reading apparatus in a state before a document is set and picked up. FIG. Explanatory explanatory drawing of the original document detection mechanism which has a filler. 1 is a schematic explanatory diagram of an image reading apparatus in which an opening / closing cover is rotated in an opening direction. Explanatory drawing which shows the behavior of a filler when an opening-and-closing cover is rotated in the open direction.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 2 is a schematic configuration diagram showing a copying machine 100 as an example of the configuration of an image forming apparatus provided with a sheet conveying apparatus according to an embodiment of the present invention. The copying machine 100 is an electrophotographic image forming apparatus, and includes a printer unit 200 that is an image forming unit and an image reading device 300. In this embodiment, a configuration including the electrophotographic printer unit 200 will be described. However, the image forming method in the image forming apparatus such as the copying machine 100 may be another method such as an ink jet method.

  The printer unit 200 is a sheet as a recording medium supplied from a paper feeding device 210 as a sheet supply unit based on image data of an image read by the image reading device 300 or image data sent from an external device. A toner image is formed on a certain sheet (recording sheet) P.

  The image reading apparatus 300 includes an automatic document feeder (ADF) 310 as a sheet conveying device and a scanner unit 320. The automatic document feeder 310 sends out a document MS that is a sheet as an image reading target set by a user, and the scanner unit 320 reads an image of the document MS sent out from the automatic document feeder 310.

  The thickness of the sheet P or the document MS to be conveyed is, for example, 50 [μm] to 500 [μm]. Sheets such as paper P and original MS, which are generally called high-quality paper and have a thickness of about 100 [μm] (for example, 100 [μm] ± 10 [μm]), are also transported.

  The printer unit 200 includes four image forming units 6 (Y, M, C, K) for forming toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). I have. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached. Each of the image forming units 6 (Y, M, C, K) includes a drum-shaped photosensitive member 1 (Y, M, C, K) as a latent image carrier, a drum cleaning device as a photosensitive member cleaning unit, and a static eliminator. A charging device, a developing device, and the like. These image forming units 6 can be attached to and detached from the printer unit 200 so that consumable parts can be replaced at a time.

  In FIG. 2, an optical writing unit 7 is disposed below the image forming unit 6 (Y, M, C, K). The optical writing unit 7 serving as a latent image forming unit emits a laser beam L emitted based on image information to each of the photoreceptors 1 (Y, M, C) in the image forming unit 6 (Y, M, C, K). , K) for exposure. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the surface of each photoreceptor 1 (Y, M, C, and K). The optical writing unit 7 sensitizes the laser light emitted from the light source through a plurality of optical lenses and mirrors while deflecting the laser light emitted from the light source in the main scanning direction (photosensitive member axial direction) by a polygon mirror that is rotationally driven by a motor. It irradiates the body.

  Below the optical writing unit 7, a sheet feeding device 210 as a sheet feeding device having a sheet storage cassette 26 and a sheet feeding separation mechanism 27 incorporated therein is disposed. The sheet storage cassette 26 stores a sheet bundle in which a plurality of sheets P are stacked. The paper feed separation mechanism 27 forms a paper feed separation nip with a paper feed feed roller 27a that can be driven to rotate and a paper feed separation pad 27b that abuts on the paper feed feed roller 27a.

  The uppermost sheet P in the sheet bundle in the sheet storage cassette 26 is in contact with the sheet feed roller 27 a of the sheet feed separation mechanism 27. The paper feed roller 27a feeds the paper P into the paper feed separation nip by its own rotational drive. When a plurality of sheets P are fed into the sheet feed separation nip, the sheet feed roller 27a contacts only the uppermost sheet P among the sheets. The uppermost sheet P follows the surface movement of the sheet feed roller 27a and moves in the sheet feeding separation nip in the feeding direction. On the other hand, the lower side paper P excluding the uppermost paper P is given load resistance by the paper feed separation pad 27b that does not move on the surface. As a result, the lower sheet P cannot move in the feeding direction following the uppermost sheet P, but remains in the sheet feed separation nip. In this way, the sheet feeding / separating mechanism 27 separates only the uppermost sheet P out of the plurality of sheets P sent out from the sheet storage cassette 26 into one sheet and feeds the first sheet from the sheet feeding / separating nip. The paper is sent out toward a paper feed path 251 which is a transport path.

  Near the intermediate point in the length direction of the paper feed path 251, a pair of transport rollers 28 is disposed as a transport unit. The conveying roller pair 28 is configured such that two rollers are brought into contact with each other to form a conveying nip, and one of the rollers is rotationally driven by a driving unit.

  In addition, a registration roller pair 29 as an abutting conveyance unit is disposed near the end in the length direction of the paper feed path 251. The registration roller pair 29 abuts two registration rollers to form a registration nip as an abutment conveyance nip. One of the two registration rollers is driven to rotate by a driving means.

  The conveyance drive roller, which is a roller that is driven to rotate the conveyance roller pair 28, is rotated almost simultaneously with the start of the rotation drive of the paper feed roller 27a of the paper feed separation mechanism 27 or with a slight time lag. Driving is started. The leading end portion of the paper P sent out from the paper feed separation nip of the paper feed separation mechanism 27 to the paper feed path 251 is eventually sandwiched between the transport nips of the transport roller pair 28. Since the transport driving roller is driven to rotate at a higher linear speed than the paper feed roller 27a, at this time, the paper P is stretched with a strong tension between the paper feed separation nip and the transport nip. When a strong torque is applied to the paper feed roller 27a, the torque limiter is activated and the paper feed roller 27a rotates around the paper P.

  Thereafter, the sheet P is sent out from the conveyance nip toward the registration roller pair 29 by the rotation drive of the conveyance driving roller, and then the leading end abuts against the registration nip of the registration roller pair 29. At this time, since the rotational driving of the registration roller pair 29 is stopped, the paper P cannot enter the registration nip and gradually bends. The skew of the paper P is corrected by this bending.

  After the sheet P starts to be fed out from the conveyance nip of the conveyance roller pair 28, when a predetermined timing comes, the rotation of the sheet feed roller 27a of the sheet separation mechanism 27 and the rotation of the conveyance roller pair 28 are performed. Stopped. Accordingly, the conveyance of the paper P is temporarily stopped in a state where the leading end is bent.

  Above the image forming unit 6 (Y, M, C, K) in FIG. 2, an intermediate transfer unit 15 that moves endlessly while stretching an intermediate transfer belt 8 as an intermediate transfer member is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 includes four primary transfer bias rollers 9 (Y, M, C, K), a belt cleaning device 10, and the like. A secondary transfer backup roller 12, a cleaning backup roller 13 and a tension roller 14 are also provided.

  The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in FIG. 2 by being driven by rotation of at least one of the rollers while being stretched around three rollers inside the loop. The primary transfer bias roller 9 (Y, M, C, K) sandwiches the intermediate transfer belt 8 thus moved endlessly between the photoreceptors (Y, M, C, K) and sets the primary transfer nip. Forming. In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All the rollers except the primary transfer bias roller 9 (Y, M, C, K) are electrically grounded. The intermediate transfer belt 8 passes through the primary transfer nips for Y, M, C, and K sequentially along with the endless movement thereof, and Y, M on the photoreceptor 1 (Y, M, C, K). , C, K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

  The secondary transfer backup roller 12 disposed on the inner side of the belt loop sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 disposed on the outer side of the belt loop to form a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the paper P at the secondary transfer nip. Untransferred toner that has not been transferred to the paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the belt cleaning device 10.

  After the rotational driving of the paper feed roller 27a and the transport roller pair 28 is temporarily stopped, when the timing at which the paper P can be synchronized with the four-color toner image on the intermediate transfer belt 8 in the secondary transfer nip comes, The rotational driving of the feed roller 27a and the conveyance roller pair 28 is resumed. Further, the rotational driving of the registration roller pair 29 is started. As a result, the sheet P is sandwiched between the registration nips of the registration roller pair 29 and then sent out from the registration nip toward the secondary transfer nip. In the secondary transfer nip, the toner image is superimposed on the four-color toner image on the intermediate transfer belt 8.

  The fixing device 20 is disposed above the secondary transfer nip, and the sheet P sent out from the secondary transfer nip is heated and pressed by the heat and pressure when passing between the fixing roller pair 230 of the fixing device 20. The four-color toner image transferred on the surface is fixed. Thereafter, the paper P is discharged out of the apparatus through the rollers of the paper discharge roller pair 30. A stack unit 31 is formed on the upper surface of the printer unit 200, and the sheets P discharged to the outside by the discharge roller pair 30 are sequentially stacked on the stack unit 31.

  A bottle container 33 is disposed between the intermediate transfer unit 15 and the stack portion 31 located above the intermediate transfer unit 15. The bottle container 33 contains toner bottles 32 (Y, M, C, K) as a replenishing toner container for storing Y, M, C, and K toners. The toner bottles 32 (Y, M, C, K) are installed on the bottle container 33 so as to be placed from the top for each toner color. The Y, M, C, and K toners in the toner bottle 32 (Y, M, C, and K) are respectively developed by the image forming unit 6 (Y, M, C, and K) by a toner replenishing device as a toner conveying unit. The device is replenished as appropriate. These toner bottles 32 (Y, M, C, K) can be attached to and detached from the printer unit 200 independently of the image forming unit 6 (Y, M, C, K).

  A switchback device is disposed in the vicinity of the fixing device 20. In the double-sided printing mode in which images are formed on both sides of the paper P, the paper P that has passed through the fixing device 20 after a toner image is formed on only one side thereof is turned upside down by the switchback device. The vertically inverted paper P is retransmitted toward the registration nip of the registration roller pair 29 via the fourth paper conveyance path 254 and the reverse path 255. Then, the toner image is sent from the registration nip to the secondary transfer nip to form a toner image on the other surface, and then the fixing device 20 performs fixing processing on the toner image on the other surface. 30 is stacked on the stack unit 31 via 30.

  As shown in FIG. 2, an image reading device 300 including an automatic document feeder 310 and a scanner unit 320 is disposed on the printer unit 200. The image reading apparatus 300 is fixed on a frame supported by two legs fixed to the back surface of the printer unit 200, and a large space is provided between the stack unit 31 of the printer unit 200 and the frame. Is intervening. The sheets P stacked on the stack unit 31 are located in the space.

  The scanner unit 320 of the image reading apparatus 300 includes a fixed reading unit 321 and a moving reading unit 322. The movable reading unit 322 is disposed directly below the second contact glass fixed to the upper wall of the casing of the scanner unit 320 so as to come into contact with the document MS, and an optical system including a light source, a reflection mirror, and the like is illustrated in FIG. It can be moved in the horizontal direction. Then, in the process of moving the optical system from the left side to the right side in FIG. 2, the light emitted from the light source is reflected by the surface of the document placed on the second contact glass, and then a plurality of reflection mirrors are provided. The light is received by the image reading sensor 323 fixed to the scanner body.

  On the other hand, the fixed reading unit 321 includes an image reading sensor such as a light source, a reflection mirror, and a CCD, and is directly below the first contact glass fixed to the upper wall of the casing of the scanner unit 320 so as to contact the document MS. It is arranged. Then, when the document MS transported by the automatic document transport device 310 passes over the first contact glass, the image reading sensor passes through the plurality of reflecting mirrors while sequentially reflecting the light emitted from the light source on the document surface. Receive light at. Thus, the first surface of the document MS is optically scanned without moving an optical system including a light source, a reflection mirror, and the like. The automatic document feeder 310 includes a second surface fixed reading unit that optically scans the second surface of the document MS.

  When a document bundle in which a plurality of documents MS are stacked is set on the automatic document feeder 310, the documents MS can be automatically conveyed one by one. Then, the image of the document MS automatically conveyed one by one can be sequentially read by the fixed reading unit 321 in the scanner unit 320 or the second surface fixed reading unit in the automatic document conveying device 310. In this case, after the original bundle is set on the original placement table 311, the copy start button is pressed. Then, the automatic document feeder 310 carries the document MS of the document bundle placed on the document placing table 311 in order from the top. In the course of this conveyance, immediately after the document MS is reversed, the original MS is passed directly above the fixed reading unit 321 of the scanner unit 320. At this time, the image on the first surface of the document MS is read by the fixed reading unit 321 of the scanner unit 320.

  The printer unit 200 of the copying machine 100 having the above-described configuration includes first to fifth sheet conveyance paths (reference numerals “251” to “255”) as sheet conveyance paths for conveying the sheet P.

  In the paper feeding path 251, the paper P supplied one by one from the paper feeding device 210 is conveyed. The paper P stored in the sheet storage cassette 26 is sent out by a paper feed roller 27a, and the secondary transfer backup roller 12 and the secondary transfer roller 19 face each other through a pair of conveyance rollers 28 and a pair of registration rollers 29. To the secondary transfer nip. In the secondary transfer nip, the toner image formed on the intermediate transfer belt 8 is transferred onto the paper P. The presence or absence of the sheet P on the sheet storage cassette 26 that stores the sheet P to be conveyed in the sheet feed path 251 is detected by a cassette sheet sensor 220 serving as a sheet detection device.

  In the second paper conveyance path 252, the paper P on which the toner image has been transferred at the secondary transfer nip passes through the nip portion of the fixing roller pair 230 of the fixing device 20 and is then conveyed toward the paper discharge roller pair 30. .

  In the third sheet conveyance path 253, the fixed sheet P is conveyed so as to be discharged onto the stack unit 31 via the discharge roller pair 30 during the single-sided image forming operation. In the third sheet conveyance path 253, the sheet P on which the toner image is formed on the front surface at the image forming position is conveyed toward the paper discharge roller pair 30 during the double-sided image forming operation. Then, the paper discharge roller pair 30 rotates in reverse at a predetermined timing when the rear end of the paper P approaches the paper discharge roller pair 30, whereby the paper P is conveyed toward the fourth paper conveyance path 254. The rear end of the paper P in the third paper transport path 253 is detected by an exit paper sensor 280 as a sheet detection device.

  In the fourth paper transport path 254, the paper P transported from the third paper transport path 253 to form an image on the back surface of the paper P during the double-sided image forming operation is further the fifth paper transport path. It is conveyed toward the reverse path 255.

  In the reverse path 255, the sheet P conveyed from the fourth sheet conveyance path 254 passes through the registration roller pair 29, and the secondary transfer nip where the secondary transfer backup roller 12 and the secondary transfer roller 19 face each other. It is conveyed to. In the secondary transfer nip, the toner image formed on the intermediate transfer belt 8 is transferred to the back surface of the paper P. The paper P in the reversing path 255 is detected by a reversing paper sensor 290 as a sheet detecting device.

  The image reading apparatus 300 includes a document conveyance path 330 as a sheet conveyance path for conveying the document MS. The document transport path 330 is formed by a transport guide member 340 having a curved guide surface with which the transported document MS contacts. In the document conveyance path 330, the document MS conveyed by the automatic document conveyance device 310 is conveyed to the image reading position of the fixed reading unit 321. Presence / absence of the document MS on the document table 311 of the automatic document feeder 310 is detected by a document detection mechanism 350 as a sheet detection device.

FIG. 3 is a cross-sectional view of the image reading apparatus 300. A conveyance path of the document MS inside the automatic document conveyance device 310 is indicated by an alternate long and short dash line arrow “A” in FIG.
The automatic document feeder 310 includes a pickup roller 301 and a document separation mechanism 40. The pickup roller 301 is a conveyance roller for taking in the document MS set on the document table 311 into the apparatus. The document separation mechanism 40 transports the uppermost one of the documents MS taken in by the pickup roller 301 toward the downstream side of the document transport path 306 by the document feed roller 302. Further, when a plurality of originals MS are captured, the uppermost original MS is separated from the other originals MS.

  When picking up the document MS, the pickup roller 301 moves downward from the position indicated by the broken line in FIG. 3 as indicated by the arrow “B” in FIG. 3 and descends to the position indicated by the solid line. Abuts on top surface of MS bundle. By rotating the pickup roller 301 in contact with the document MS in the clockwise direction in FIG. 3, the document MS in contact with the pickup roller 301 is drawn into the apparatus. When the reading operation of the bundle of documents MS is completed, the pickup roller 301 is moved upward to enter a standby state in which the document MS is separated from the document table 311 by a predetermined distance. As a result, the user can set the next bundle of documents MS on the document table 311.

The pickup roller 301 is rotatably held by a pickup holder 301a, and the pickup holder 301a swings up and down via a bidirectional torque limiter provided on the rotation shaft of the document feed roller 302.
When the document transport motor, which is a driving source for driving the pickup roller 301 and the document feed roller 302, is rotating in the forward direction, the pickup holder 301a moves in the direction in which the end on the side holding the pickup roller 301 descends (in FIG. 3). In the direction of arrow “B”). When the pickup roller 301 comes into contact with the upper surface of the document MS, the rotation of the pickup holder 301a is stopped by the action of the bidirectional torque limiter.
On the other hand, when the document transport motor is rotated in the reverse direction, the pickup holder 301a rotates in the direction in which the end on the side holding the pickup roller 301 rises (the direction opposite to the arrow “B” direction in FIG. 3). Then, the pickup holder 301a comes into contact with the opening / closing cover 360, and the rotation of the pickup holder 301a is stopped by the action of the bidirectional torque limiter.

  The document MS separated into one sheet by the document separation mechanism 40 is transported toward the reading unit 331 by the first document transport roller pair 303 and the second document transport roller pair 304. Then, based on the detection result of the original registration sensor 332, the original is read by matching the timing of reading by the fixed reading unit 321 with the leading edge of the original MS. The document MS whose image has been read by the reading unit 331 is discharged to the document discharge tray 313 by the document discharge roller 305.

  4 is a cross-sectional view of the upper portion of the automatic document feeder 310, and FIG. 1 is an enlarged sectional view of the vicinity of the document detection mechanism 350 in the automatic document feeder 310 shown in FIG. FIG. 5 is a perspective sectional view of the vicinity of the document detection mechanism 350 in the automatic document feeder 310.

  The automatic document feeder 310 of the present embodiment includes a pickup roller 301 as a conveyance member that applies a conveyance force to the document MS that is a sheet. The document detection mechanism 350 is a filler 2 that is a rotation member that rotates around the filler rotation shaft 2a when the conveyed document MS comes into contact with it, and a position detection unit that detects the rotation position of the filler 2. A light transmission sensor 4 is provided. The light transmission sensor 4 includes a light emitting part and a light receiving part on the front side and the back side in FIG. 1 with the light shielding part 2b in the filler 2 interposed therebetween, and is based on a light reception signal of the light receiving part when the light emitting part emits light. Thus, it is detected whether or not the light shielding part 2b is present in the detection area between the light emitting part and the light receiving part. Based on the detection result, the presence / absence of a document at a position to which the conveying force is applied by the pickup roller 301 is detected.

  The filler 2 has a filler rotation shaft 2a which is a holding shaft at one end thereof, and is held by the open / close cover 360 in a state where the filler 2 can only rotate about the filler rotation shaft 2a. The other end of the filler 2 is provided with a light shielding portion 2b, and has a document contact surface 2d on the filler rotating shaft 2a side with respect to the light shielding portion 2b, and when there is no document MS at a predetermined detection position, The detection area of the light transmission sensor 4 attached to the side is shielded.

  When the document MS is inserted into the document transport path 306, the leading edge of the document MS comes into contact with the document contact surface 2d of the filler 2 and the posture of the filler 2 is displaced. It will be in the state which is not shielded. When the document MS is further transported downstream and passes through a range where it contacts the filler 2, the filler 2 moves again to a position where the detection area of the light transmission sensor 4 is shielded by its own weight. When there is no document MS in the area in contact with the filler 2, the filler 2 comes to rest with a part of the document contact surface 2 d in contact with the cushion 11 disposed on the transport frame 5. Then, by opening and closing the opening / closing cover 360, the light shielding portion lower surface 2 c and the document contact surface 2 d of the filler 2 slide with the cushion 11.

  The filler 2 has a bent portion at the tip of a portion extending linearly from the filler rotating shaft 2a, and the light shielding portion 2b is located on the tip side of the bent portion. The lower surface of the portion of the filler 2 that is closer to the base than the bent portion is a document contact surface 2d that can contact the leading edge of the document MS when the document MS is set.

  FIG. 6 shows an upper portion of the automatic document feeder 310 in a state where the filler 2 is rotated in the clockwise direction in FIGS. 1 and 4 around the filler rotation shaft 2a from the state shown in FIGS. It is sectional drawing. The document MS set at a position to which the conveying force is applied by the pickup roller 301 to the filler 2 in the state shown in FIGS. 1, 4, and 5 comes into contact with the document contact surface 2 d of the filler 2 to fill the filler 2. The state shown in FIG. 6 is obtained by pushing up.

  FIG. 7 is a schematic explanatory view schematically showing the image reading apparatus 300 in the state shown in FIGS. 1, 4, and 5, and shows a state before the document MS is set on the document placement table 311. . FIG. 8 is a schematic explanatory view schematically showing the image reading apparatus 300 in the state shown in FIG. 6, and shows a state before the document MS is set on the document table 311 and picked up.

The automatic document feeder 310 in the image reading apparatus 300 includes an open / close cover 360 that is pivotally attached to the carrier frame 5 that constitutes the apparatus main body about a cover rotation shaft 360a. A document conveyance path 306 through which the document MS conveyed between the opening / closing cover 360 and the conveyance frame 5 passes is formed.
The automatic document feeder 310 shown in FIG. 7 is in a state in which the open / close cover 360 is closed, and from this state, the open / close cover 360 is rotated in the direction of the arrow “D” in FIG. 7 around the cover rotation shaft 360a. A part of the document conveyance path 306 is exposed.
A cushion 11 that is an elastic member is provided at a portion of the transport frame 5 where the filler 2 abuts before the document MS is set.

  In the state before the document MS shown in FIG. 7 is set, the filler 2 is in contact with the cushion 11 and the light shielding portion 2b is in a position where the light from the light transmission sensor 4 is shielded. In a state before the document MS shown in FIG. 8 is set and picked up, the filler 2 is pushed up by the leading edge of the document MS, and the light of the light transmission sensor 4 is not blocked by the filler 2, and the light transmission sensor 4 is Detects that MS is present.

FIG. 9 is an enlarged explanatory view of the document detection mechanism 350 having the filler 2.
The filler 2 is assembled to the opening / closing cover 360 so as to be rotatable about the filler rotation shaft 2a as indicated by an arrow “E” in FIG. The filler 2 is disposed so as to straddle the document conveyance path 306 that is a sheet passing path in a state before the document MS is set. Further, the document contact surface 2 d is disposed so that a part of the document contact surface 2 d comes into contact with the cushion 11 disposed on the conveyance frame 5 located on the opposite side of the opening / closing cover 360 across the document conveyance path 306. By being arranged in this way, the light shielding part 2 b of the filler 2 is positioned between the light emitting part and the light receiving part of the light transmission sensor 4.

  When the document MS is set, the leading edge of the document MS comes into contact with the document contact surface 2d of the filler 2, and the filler 2 is pushed up and displaced. When the set original MS is conveyed to the pickup roller 301 and the contact between the filler 2 and the original MS is lost, the filler 2 returns to the position where it abuts against the cushion 11 by its own weight.

  10 shows an image reading apparatus in a state in which the opening / closing cover 360 is rotated counterclockwise in FIG. 7 (in the direction of arrow “D” in FIG. 10) around the cover rotation shaft 360a from the state shown in FIG. 3 is a schematic explanatory diagram schematically showing 300. FIG. FIG. 11 is an explanatory diagram showing the behavior of the filler 2 when the opening / closing cover 360 is rotated from the state shown in FIG. 7 to the state shown in FIG.

  As shown in FIG. 10, when the opening / closing cover 360 rotates around the cover rotation shaft 360a, the filler 2 rotates about the filler rotation shaft 2a with respect to the opening / closing cover 360 by its own weight as shown in FIG. To do.

  At this time, until the center of gravity of the filler 2 reaches below the filler rotating shaft 2a vertically or the distance from the filler rotating shaft 2a to the cushion 11 becomes longer than the length from the filler rotating shaft 2a to the filler 2. The filler 2 and the cushion 11 are kept in contact with each other. Although the distance from the filler rotating shaft 2a to the cushion 11 changes with the rotation of the opening / closing cover 360 while continuing to contact in this way, the position of the filler 2 in contact with the cushion 11 is displaced, and the filler 2 is cushioned. 11 to slide. By this sliding, the deposits of the filler 2 move to the cushion 11, and the cushion 11 functions as a cleaning means for the filler 2. Thereby, the number of parts can be reduced.

  The filler 2 in a state in which the open / close cover 360 is closed is located at a position indicated by a broken line in FIG. 11, and the leading end side of the document contact surface 2 d contacts the cushion 11. From this state, the document contact surface in the filler 2 is rotated until the filler 2 reaches the position indicated by the solid line in FIG. 11 by rotating in the direction in which the opening / closing cover 360 is released (direction of arrow “D” in FIG. 11). The front end side of 2d rubs against the cushion 11. In FIG. 11, the corner of the bent portion of the filler 2 is in contact with the cushion 11, and when the opening / closing cover 360 is further rotated in this direction, the light shielding portion lower surface 2 c, which is the lower surface of the light shielding portion 2 b, slides on the cushion 11. Rub. In other words, the document contact surface 2 d and the light-shielding portion lower surface 2 c of the filler 2 rub against the cushion 11 in conjunction with the opening / closing operation of the opening / closing cover 360.

  The document contact surface 2d of the filler 2 is easy to adhere paper dust because the document MS rubs, but the document contact surface 2d rubs against the cushion 11 in conjunction with the opening / closing operation of the opening / closing cover 360 and is cleaned. Therefore, foreign matter such as paper dust attached to the original contact surface 2d can be removed.

  The light-shielding portion lower surface 2c of the filler 2 is a detection region of the light transmission sensor 4 due to a push-up operation when the original MS is set and a rotation operation of the filler 2 due to the movement of the filler 2 due to its own weight when the original MS is lost. It moves between the light emitting part and the light receiving part. If foreign matter adheres to the light shielding unit lower surface 2c, when the light shielding unit lower surface 2c moves between the light emitting unit and the light receiving unit by the rotation of the filler 2, the surface of the light emitting unit or the light receiving unit There is a possibility that foreign matter may move to the detection surface of the light transmission sensor 4 such as the surface. When the foreign matter moves and adheres to the detection surface, light is blocked by the foreign matter, and the filler 2 is positioned in the detection region even though the filler 2 is pushed up by the original MS and is out of the detection region. There is a risk of false detection.

On the other hand, since the light shielding portion lower surface 2c is cleaned by sliding against the cushion 11 in conjunction with the opening / closing operation of the opening / closing cover 360, foreign matter adhering to the light shielding portion lower surface 2c can be removed. It is possible to prevent foreign matters from moving from 2c to the detection surface of the light transmission sensor 4. As a result, it is possible to prevent erroneous detection caused by the foreign matter remaining in the detection area such as the detection surface of the light transmission sensor 4.
The filler 2 slides against the cushion 11 in conjunction with the opening / closing operation of the opening / closing cover 360, so that the filler can be opened and closed every time the opening / closing cover 360 is opened without performing an operation only for cleaning the filler 2. 2 cleaning can be performed.

The automatic document conveyance device 310 as the sheet conveyance device of the present embodiment uses the filler 2 that is a rotation member and the light transmission sensor 4 that is a rotation position detection unit as a method of determining the presence or absence of the document MS.
In this type of sheet conveying apparatus, erroneous detection occurs in the rotational position detecting means due to malfunction of the rotating member, operation sound is generated when the rotating member rotates, or the sheet is conveyed. Therefore, there has been a problem that paper dust, dust, and the like are accumulated on the rotating member.

As a malfunction of the rotation member, when the rotation member rotated by contact with the sheet rotates in the reverse direction to return to the original position after passing through the sheet, it bounces at a member that restricts the rotation range. There is chattering.
In the automatic document feeder 310 of the present embodiment, the document MS comes into contact with the filler 2 in the state shown in FIG. 1 and the filler 2 rotates, and after passing through the document MS, returns to the state shown in FIG. When it rotates, it strikes against the cushion 11 that regulates the rotation range. The cushion 11 is made of a sponge or the like, and has a function as a buffering means for reducing an impact at the time of contact with the filler 2. For this reason, it is possible to prevent erroneous detection in the light transmission sensor 4 due to malfunction of the filler 2 by suppressing the filler 2 from bouncing after passing through the document MS and preventing chattering. Thereby, the presence or absence of the document MS can be detected with high accuracy.

In addition, the cushion 11 reduces the impact sound between the filler 2 and the member that regulates the rotation range when the filler 2 returns to the original position after passing through the document MS in order to reduce the impact at the time of contact with the filler 2. It is possible to suppress the noise during conveyance of the document MS.
Since the filler 2 is rubbed against the conveyed document MS, paper dust generated from the document MS and foreign matter attached to the document MS are likely to adhere. On the other hand, a cushion 11 having a function as a cleaning means for cleaning the filler 2 is provided, and foreign matters such as paper dust attached to the filler 2 can be removed. Thereby, it is possible to prevent paper powder, dust, and the like from accumulating in the filler 2.

  The automatic document feeder 310 sets the document MS so that the document contact surface 2d of the filler 2 is pushed up by the document MS, so that the filler 2 is positioned between the light emitting unit and the light receiving unit, which are detection areas of the light transmission sensor 4. Move to a position outside of When the document MS disappears from the position of the filler 2, the filler 2 moves to the collision position in the transport frame 5 due to its own weight. A sponge-like cushion 11 is disposed at the collision position. The cushion 11 is disposed at a position where the document contact surface 2d and the light shielding portion lower surface 2c of the filler 2 can slide by the opening / closing operation of the opening / closing cover 360. In the automatic document feeder 310, the collision of the filler 2 with the apparatus main body is buffered and the bounce is eliminated, so that erroneous detection of the light transmission sensor 4 can be prevented and the operation sound is reduced by eliminating the collision sound. Further, since the light shielding portion lower surface 2c of the filler 2 comes into contact with the cushion 11 in conjunction with the opening / closing operation of the opening / closing cover 360, paper dust and dirt accumulated on the filler 2 can be cleaned by passing paper.

The filler 2 is located at a different position from the light shielding portion 2b that is a portion that enters the detection region of the light transmission sensor 4 and a portion that has the document contact surface 2d that is a portion that contacts the document MS. As shown in FIG. 1, the filler 2 has a bent portion in the vicinity of the tip, and the portion having the document contact surface 2d that can be contacted by the document MS is a portion closer to the root than the bent portion. On the other hand, the light shielding portion 2b is located at a portion where the leading edge of the document MS on the leading end side with respect to the bent portion does not contact.
The movement of the paper dust and foreign matter from the original MS is different because the position of the original contact surface 2d where the movement of the paper dust and foreign matters from the original MS is likely to occur and the light shielding portion 2b entering the detection area of the light transmission sensor 4 are different. It is possible to prevent a portion that is likely to occur from entering the detection region of the light transmission sensor 4. Thereby, it can suppress that a detection area | region becomes dirty with paper dust and a foreign material, and can prevent the fall of detection accuracy.

  When the rear end of the document MS passes through a range where it contacts the filler 2, the document MS may also contact the light shielding portion lower surface 2c of the light shielding portion 2b. Due to this contact, paper dust and dirt accumulated on the lower surface 2 c of the light shielding part may enter the detection region of the light transmission sensor 4. By positively accumulating the paper dust and dust accumulated on the document contact surface 2d on the cushion 11 made of a foaming elastic member, foreign matter can be prevented from entering the detection region of the light transmission sensor 4. The cushion 11 is a foaming material and can prevent foreign matters such as paper dust from clogging the cushion 11 and diffusing to the outside.

  Since the foreign matter does not diffuse outside, the foreign matter can be prevented from staying on the document contact surface 2d and the light shielding portion lower surface 2c, and the bound shock absorbing performance and cleaning performance of the filler 2 by the cushion 11 can be maintained.

  In the above-described embodiment, when the document MS that is a sheet comes into contact, the filler 2 that is a movable member rotates, and the light transmission sensor 4 that is a position detection unit detects the rotation position of the filler 2. . The movable member is not limited to a member that rotates by contact of the sheet, but may be any member that moves by contact of the sheet. For example, it may be a member that moves in parallel with the contact of the sheet. Further, the position detecting means is not limited to a light transmission type sensor, and any means capable of detecting a change in the position of the movable member due to contact with the sheet may be used.

In the above-described embodiment, the case where the sheet conveying apparatus including the separating unit that conveys the multi-fed sheets as one sheet is the automatic document conveying apparatus (ADF) as the document conveying unit that conveys the document has been described. The sheet conveying device including the separating unit is not limited to the automatic document feeder, and any sheet conveying device including the separating unit is applicable. For example, the present invention can also be applied to a paper feeding device 210 that transports the paper P stored in the sheet storage cassette 26 toward the printer unit 200.
Further, the configuration similar to the document detection mechanism 350 including the rotation member that detects the presence or absence of the sheet and the rotation position detection means is not limited to the configuration that is arranged at the upstream end portion in the conveyance direction in the sheet conveyance path. It can be used for a detection mechanism for detecting the passage of a conveyed sheet, such as “280” and “290” in FIG.

  Sheets conveyed by the sheet conveying apparatus according to the present invention include plain paper, cardboard, postcard, envelope, thin paper, coated paper (coated paper, art paper, etc.), label paper, OHP sheet, fabric, recording sheet, film, and the like. Means a medium to which a developer or ink can be attached. Also included are recording media, recording media, recording paper, recording paper, and the like.

  In the present exemplary embodiment, the case where the image forming apparatus including the sheet conveying device according to the present invention is a copying machine including an electrophotographic image forming unit has been described. The image forming apparatus according to the present invention is not limited to this, and any image forming apparatus having a mechanism for conveying a sheet, such as a facsimile, a printer, a printing machine, and an ink jet recording apparatus, can be applied.

An “image forming apparatus” to which the present invention can be applied means image formation by attaching a developer or ink to a medium such as paper, an OHP sheet, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. Means a device that performs
“Image formation” not only means that an image having a meaning such as a character or a figure is given to the medium but also an image having no meaning such as a pattern is given to the medium.

  What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.

(Aspect A)
A conveying member such as a pick-up roller 301 that applies a conveying force to a sheet such as the document MS, a movable member such as a filler 2 that moves when the conveyed sheet contacts, a light transmission sensor 4 that detects the position of the movable member, and the like. In a sheet conveying apparatus such as an automatic document conveying apparatus 310 provided with a position detecting means, a cleaning means such as a cushion 11 for cleaning the movable member is provided.
According to this, as described in the above embodiment, foreign matters such as paper dust attached to the movable member from the sheet by contact with the sheet can be removed by the cleaning unit, and the foreign matter adheres to the position detecting unit from the movable member. Can be prevented. For this reason, it is possible to suppress erroneous detection due to foreign matter adhering to the position detection means.

(Aspect B)
In the aspect A, the cleaning means such as the cushion 11 cleans a portion (original contact surface 2d) where a sheet such as the original MS contacts in a movable member such as the filler 2.
According to this, as described in the above-described embodiment, it is possible to clean a portion where the sheet contacts in the movable member to which foreign matters such as paper dust easily adhere because the sheet rubs. For this reason, it is possible to prevent foreign matter from accumulating at the portion of the movable member that contacts the sheet, to prevent the accumulated foreign matter from adhering to the position detection means such as the light transmission sensor 4, and to prevent the foreign matter from entering the position detection means. It is possible to suppress erroneous detection due to adhesion.

(Aspect C)
In the aspect A or B, the position detection means such as the light transmission sensor 4 is such that the detected part such as the light shielding part 2b in the movable member such as the filler 2 is present in a detection region such as between the light emitting part and the light receiving part. It is the structure which detects whether or not.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the position detection unit detects the position of the movable member.

(Aspect D)
In aspect C, the cleaning means such as the cushion 11 cleans a portion (such as the light shielding portion lower surface 2c) that enters the detection region such as between the light emitting portion and the light receiving portion in the movable member such as the filler 2. .
According to this, as described in the above embodiment, it is possible to prevent erroneous detection due to foreign matter remaining in the detection region such as the detection surface of the light transmission sensor 4.

(Aspect E)
In Aspect C or D, the position where the portion (such as the light shielding portion 2b) that enters the detection region such as between the light emitting portion and the light receiving portion of the movable member such as the filler 2 is different from the portion where the sheet such as the document MS contacts It is characterized by being.
According to this, as described in the above-described embodiment, it is possible to prevent a portion where the movement of the foreign matter from the sheet is likely to enter the detection area of the position detection unit such as the light transmission sensor 4. Thereby, it can suppress that a detection area | region is contaminated with foreign materials, such as paper dust, and can prevent the fall of detection accuracy.
Further, when the foreign matter accumulated in the portion of the movable member that comes into contact with the sheet is cleaned by the cleaning means such as the cushion 11, it can be prevented from moving to the portion of the movable member that enters the detection region.

(Aspect F)
In any one of the aspects A to E, an opening / closing member such as an opening / closing cover 360 that moves from the closed state to the released state is provided, and the cleaning means such as the cushion 11 is linked to the opening / closing operation of the opening / closing member, and the filler 2 etc. The movable member is cleaned.
According to this, as described in the above embodiment, the movable member can be cleaned each time the opening and closing member is opened and closed.

(Aspect G)
In any one of the aspects A to F, the movable member such as the filler 2 is a rotating member that rotates by contacting a sheet such as the document MS being conveyed.
According to this, as described in the above embodiment, foreign substances such as paper dust that has moved from the sheet and adhered to the rotating member by contact with the sheet can be removed by the cleaning means, and the position from the rotating member can be reduced. It is possible to suppress erroneous detection caused by foreign matter adhering to the detection means.

(Aspect H)
In aspect F, the movable member such as the filler 2 is a rotating member that rotates when the sheet such as the document MS being conveyed contacts, and the rotation shaft such as the filler rotation shaft 2a of the rotating member is an opening / closing cover. It is provided in an opening / closing member such as 360.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the rotating shaft is moved by the opening / closing operation of the opening / closing member and the movable member is cleaned in conjunction with the opening / closing operation of the opening / closing member.

(Aspect I)
In any of the aspects A to H, the movable range regulating member such as the cushion 11 that regulates the movable range by contacting the movable member such as the filler 2 is provided, and the movable range regulating member has a function of a cleaning unit. Features.
According to this, as described in the above embodiment, the number of parts can be reduced.

(Aspect J)
In the aspect I, the movable range restricting member such as the cushion 11 has a function as a buffering means for reducing the impact at the time of contact with the movable member such as the filler 2.
According to this, as described in the above embodiment, it is possible to suppress the bounce of the movable member after the passage of the sheet such as the document MS and to prevent the occurrence of chattering, thereby preventing the light caused by the malfunction of the movable member. It is possible to prevent erroneous detection by the position detection means that is the transmission sensor 4. Thereby, the presence or absence of the sheet can be detected with high accuracy.

(Aspect K)
In any one of the aspects A to J, the cleaning means such as the cushion 11 is a porous body such as a foaming sponge.
According to this, as described in the embodiment, it is possible to prevent foreign matters such as paper dust from clogging the porous body and diffusing outside.

(Aspect L)
In an image reading apparatus such as an image reading apparatus 300 including a sheet conveying unit that conveys a sheet such as a document MS and an image reading unit such as a scanner unit 320 that reads an image on the surface of the sheet conveyed by the sheet conveying unit. The sheet conveying unit includes a sheet conveying apparatus such as the automatic document conveying apparatus 310 according to any one of aspects A to K.
According to this, it is possible to realize an image reading apparatus capable of accurately detecting the presence or absence of a sheet and performing appropriate image reading.

(Aspect M)
In an image forming apparatus such as a copying machine 100 including an image reading unit and an image forming unit such as the printer unit 200 that forms an image based on a read image read by the image reading unit. An image reading device such as an automatic document feeder 310 is provided.
According to this, it is possible to realize an image forming apparatus capable of performing appropriate image formation by performing appropriate image reading with the image reading apparatus.

(Aspect N)
In an image forming apparatus such as a copying machine 100, which includes a sheet conveying unit that conveys a sheet such as an original MS, and an image forming unit such as a printer unit 200 that forms an image on the sheet conveyed by the sheet conveying unit. As an example, an image reading apparatus 300 that is a sheet conveying apparatus according to any one of aspects A to K is provided.
According to this, it is possible to realize an image forming apparatus capable of accurately detecting the presence or absence of a sheet and performing appropriate image formation.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Original contact surface 2 Filler 2a Filler rotation shaft 2b Light shielding part 2c Light shielding part lower surface 2d Original contact surface 4 Light transmission sensor 5 Carrying frame 6 Image forming unit 7 Optical writing unit 8 Intermediate transfer belt 9 Primary transfer bias roller DESCRIPTION OF SYMBOLS 10 Belt cleaning apparatus 11 Cushion 12 Secondary transfer backup roller 13 Cleaning backup roller 14 Tension roller 15 Intermediate transfer unit 19 Secondary transfer roller 20 Fixing device 26 Sheet storage cassette 27 Paper feed separation mechanism 27a Paper feed roller 27b Paper feed separation pad 28 Transport roller pair 29 Registration roller pair 30 Paper discharge roller pair 31 Stack unit 32 Toner bottle 33 Bottle container 40 Document separation mechanism 100 Copier 200 Printer unit 210 Paper feed device 220 Cassette paper sensor 230 Fixing roller pair 25 1 Paper feed path 252 Second paper transport path 253 Third paper transport path 254 Fourth paper transport path 255 Reverse path 280 Exit paper sensor 290 Reverse paper sensor 300 Image reading device 301 Pickup roller 301a Pickup holder 302 Document feed roller 303 First Document transport roller pair 304 Document transport roller pair 305 Document discharge roller 306 Document transport path 310 Automatic document transport device 311 Document stacking table 313 Document discharge tray 320 Scanner unit 321 Fixed reading unit 322 Moving reading unit 323 Image reading sensor 330 Document transport path 331 Reading unit 332 Document registration sensor 340 Transport guide member 350 Document detection mechanism 360 Open / close cover 360a Cover rotation shaft

JP 2015-16922 A

Claims (14)

A conveying member that imparts conveying force to the sheet;
A movable member that moves in contact with the conveyed sheet;
In a sheet conveying apparatus provided with a position detecting means for detecting the position of the movable member,
A sheet conveying apparatus comprising: a cleaning unit that cleans the movable member. In the sheet conveying apparatus according to claim 1,
The sheet conveying apparatus, wherein the cleaning unit cleans a portion of the movable member that contacts the sheet. In the sheet conveying apparatus according to claim 1 or 2,
The sheet conveying apparatus according to claim 1, wherein the position detecting unit is configured to detect whether or not the detected portion of the movable member is in a detection area. In the sheet conveying apparatus according to claim 3,
The cleaning means cleans a portion of the movable member that enters the detection area. In the sheet conveying apparatus according to claim 3 or 4,
The sheet conveying apparatus, wherein a portion of the movable member that enters the detection region is different from a portion that contacts the sheet. In the sheet conveying apparatus according to any one of claims 1 to 5,
An opening / closing member that moves from a closed state to a released state,
The sheet conveying apparatus, wherein the cleaning unit cleans the movable member in conjunction with an opening / closing operation of the opening / closing member. In the sheet conveying apparatus according to any one of claims 1 to 6,
The sheet conveying apparatus according to claim 1, wherein the movable member is a rotating member that rotates in contact with the conveyed sheet. In the sheet conveying apparatus according to claim 6,
The movable member is a rotating member that rotates when the conveyed sheet comes into contact therewith,
A sheet conveying apparatus, wherein a rotation shaft of the rotation member is provided on the opening / closing member. In the sheet conveying apparatus according to any one of claims 1 to 8,
A sheet conveying apparatus comprising: a movable range regulating member that contacts the movable member to regulate a movable range, wherein the movable range regulating member has a function of the cleaning unit. The sheet conveying apparatus according to claim 9,
The sheet conveying apparatus according to claim 1, wherein the movable range restricting member has a function as a buffer means for reducing an impact at the time of contact with the movable member. In the sheet conveying apparatus according to any one of claims 1 to 10,
The sheet conveying apparatus, wherein the cleaning means is a porous body. Sheet conveying means for conveying the sheet;
In an image reading apparatus comprising image reading means for reading an image on the surface of the sheet conveyed by the sheet conveying means,
An image reading apparatus comprising the sheet conveying apparatus according to claim 1 as the sheet conveying unit. Image reading means;
An image forming apparatus comprising: an image forming unit that forms an image based on a read image read by the image reading unit;
An image forming apparatus comprising the image reading apparatus according to claim 12 as the image reading unit. Sheet conveying means for conveying the sheet;
An image forming apparatus comprising: an image forming unit that forms an image on the sheet conveyed by the sheet conveying unit;
An image forming apparatus comprising the sheet conveying device according to claim 1 as the sheet conveying unit.

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