JP6788819B2 - Sheet transfer device and image formation system - Google Patents

Description

The present invention relates to a sheet transport device for transporting a sheet material and an image forming system including the same.

Conventionally, a sheet transport device having a transport path for transporting a sheet material and an exterior cover covering the transport path is known.

For example, the automatic document transfer device described in Patent Document 1 as a sheet transfer device has a transfer path for transporting a document sheet, which is a sheet material, and a paper feed cover as an exterior cover that covers the transfer path.

In an automatic document device having such a configuration, the tip of the document sheet is paired with a transfer roller in order to correct the rubbing noise between the guide plate constituting the transfer path and the document sheet being transferred and the skew of the document sheet in the transfer path. It may generate a bumping noise when hitting against the nip. If the rubbing noise or bumping noise is transmitted to the air outside the aircraft through the air inside the aircraft and the exterior cover, it may reach the user's ears as noise.

In order to solve the above-mentioned problems, the present invention relates to a sheet transport device having a pair of guide plates sandwiching a transport path for transporting a sheet material and an exterior cover covering the pair of guide plates. Has a structure in which a gap is formed between the inner member facing the pair of guide plates and the outer member in contact with the outside air, and one of the inner member and the outer member is provided with a hooking portion for being hooked on the other. A soft elastic member that is sandwiched between the inner member and the outer member and deforms by compression is provided in the gap, and the outer member is attached to the inner member by being caught by the hooked portion by the restoring force from the compression of the soft elastic member. It is characterized by being retained .

According to the present invention, there is an excellent effect that the noise caused by the rubbing noise and the bumping noise generated in the transport path can be reduced.

The schematic block diagram which shows the image formation system which concerns on embodiment. The block diagram which shows the image formation unit for Y in the image formation system. The perspective view which shows the scanner and ADF of the image formation system. The block diagram which shows the main part structure of the ADF together with the upper part of a scanner. The block diagram which shows the main part of the electric circuit of the ADF. The block diagram which shows the main part of the electric circuit of the 2nd surface reading sensor in the ADF together with the controller and the main body control part. The figure which shows the transport path and its surroundings immediately after a document is made into the abutting part. The figure which shows the transport path and its surroundings in a state where the transport of a document at a butt portion is temporarily stopped. The figure which shows the transport path immediately after resuming the transport of a document at the abutting part, and the periphery thereof. The figure which shows the transport path in a state which transports a document in a turn part, and the periphery thereof. The block diagram which shows the same ADF in the state which the feeding cover unit is opened. The figure which shows the outer cover of the paper feed cover in ADF of the image formation system which concerns on embodiment. The figure which shows the ADF.

Hereinafter, embodiments in which the present invention is applied to an electrophotographic printing unit and an image forming system including an image reading unit will be described.
First, the basic configuration of the image forming system according to the embodiment will be described. FIG. 1 is a schematic configuration diagram showing an image forming system according to an embodiment. In the figure, this image forming system includes a printing unit 100 as an image forming means and an image reading unit 200. The image reading unit 200 as an image reading device includes a scanner 201 which is an image reading means fixed on the printing unit 100 and an automatic document conveying device (hereinafter referred to as ADF) 251 which is a sheet conveying device supported by the scanner 201. Have.

The print unit 100 includes four image-forming units 6Y, 6M, 6C, and 6K for image-forming toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). .. These use Y, M, C, and K toners of different colors as the image forming substance, but have the same configuration other than that, and are replaced when the life is reached. Taking the image forming unit 6Y for forming a Y toner image as an example, this is a drum-shaped photoconductor 1Y, a drum cleaning device 2Y, a static eliminator, a charging device 4Y, a developing device 5Y, etc., as shown in FIG. Is equipped with. The image forming unit 6Y can be attached to and detached from the main body of the printing unit 100, and consumable parts can be replaced at once.

The charging device 4Y uniformly charges the surface of the photoconductor 1Y which is rotated clockwise in the drawing by the driving means. The surface of the uniformly charged photoconductor 1Y is exposed and scanned by a laser beam L emitted from an optical writing unit 7 as a latent image forming means to carry an electrostatic latent image for Y. This electrostatic latent image of Y is developed into a Y toner image by a developing device 5Y that uses Y toner. Then, the intermediate transfer is performed on the intermediate transfer belt 8. The drum cleaning device 2Y removes the toner remaining on the surface of the photoconductor 1Y after the intermediate transfer step. Further, the static eliminator removes the residual charge of the photoconductor 1Y after cleaning. By this static elimination, the surface of the photoconductor 1Y is initialized to prepare for the next image formation. Similarly, in the other image forming units 6M, C, K, M, C, K toner images are formed on the photoconductors 1M, C, K and intermediately transferred onto the intermediate transfer belt 8.

The developing apparatus 5Y develops a latent image using a two-component developer (hereinafter referred to as a developer) containing a magnetic carrier and a non-magnetic Y toner. The stirring unit that conveys the developer contained therein while stirring and supplies it to the developing roll 51Y, and the Y toner in the developing agent supported on the surface of the tubular developing sleeve provided in the developing roll 51Y. It has a developing unit 53Y for transferring to the photoconductor 1Y. The developing roll 51Y includes a developing sleeve made of a non-magnetic pipe and a magnet roller contained therein so as not to be carried around the developing roll 51Y. The developing agent is attracted to the developing sleep surface by the magnetic force generated by the magnet roller. Let me.

The stirring unit is provided at a position lower than the developing unit 53Y, and the supply unit 55Y that supplies the developer to the developing roll 51Y while stirring and transporting the developer and the supply unit 55Y that supplies the developer received from the supply unit 55Y while stirring. It has a circulation unit 54Y that circulates and conveys toward 55Y.

The supply unit 55Y conveys the developer along the longitudinal direction of the screw by rotationally driving the first stirring transfer screw 56Y arranged so as to be parallel to the developing roll 51Y. In this process, the developer is supplied to the developing sleeve of the developing roll 51Y. The developer conveyed to the vicinity of the longitudinal end of the first stirring transfer screw 56Y passes through the first communication port provided near the end in the partition wall separating the supply portion 55Y and the circulation portion 54Y. , Enter the circulation portion 54Y.

The circulation unit 54Y transfers the developer along the longitudinal direction of the screw by rotationally driving the second stirring transfer screw 57Y arranged so as to be in a posture parallel to the developing roll 51Y and the first stirring transfer screw 56Y. 1 Stirring transport Conveys in the opposite direction to the screw 56Y. The developer conveyed to the vicinity of the end portion in the longitudinal direction of the second stirring transfer screw 57Y returns to the inside of the supply unit 55Y through the second communication port provided near the end portion of the partition wall.

The developing unit 53Y has, in addition to the developing roll 51Y, a doctor blade 52Y whose tip is brought close to the developing sleeve of the developing roll 51Y. In the developing roll 51Y, the magnet roller included in the developing sleeve has a plurality of magnetic poles that are sequentially arranged in the direction of rotation of the sleeve from the position facing the doctor blade 52Y. Each of these magnetic poles exerts a magnetic force on the developer on the sleeve at a predetermined position in the rotational direction. As a result, the developer supplied from the supply unit 55Y is attracted to and supported on the surface of the developing sleeve, and a magnetic brush along the lines of magnetic force is formed on the surface of the sleeve.

The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 52Y as the developing sleeve rotates, and then is conveyed to the developing region facing the photoconductor 1Y. Then, the Y toner is transferred onto the electrostatic latent image by the potential difference between the development bias applied to the developing sleeve and the electrostatic latent image of the photoconductor 1Y, and contributes to the development. Further, it returns to the inside of the developing section 53Y again with the rotation of the developing sleeve, separates from the sleeve surface due to the influence of the repulsive magnetic field formed between the magnetic poles of the magnet roller, and then returns to the inside of the supply section 55Y.

An appropriate amount of toner is replenished to the circulation unit 54Y based on the detection result of the toner concentration sensor that detects the toner concentration of the developer in the circulation unit 54Y. As the developing apparatus 5Y, a developing device 5Y that uses a one-component developer that does not contain a magnetic carrier may be used instead of the one that uses a developing agent.

In FIG. 1, an optical writing unit 7 is arranged in the lower part of the image forming units 6Y, M, C, and K. The optical writing unit 7 as a latent image forming means irradiates and exposes the photoconductors in the image forming units 6Y, M, C, and K with the laser light L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoconductors 1Y, M, C, and K. In the optical writing unit 7, the laser beam L emitted from the light source is deflected in the main scanning direction (photoreceptor axis direction) by a polygon mirror rotationally driven by a motor, and the laser beam L is deflected through a plurality of optical lenses and mirrors. It irradiates the photoconductor.

Below the optical writing unit 7, a sheet accommodating cassette 26, a separation means 27 incorporated therein, and the like are arranged. The sheet accommodating cassette 26 stores a plurality of recording sheets P in a state of a stack of sheets. Further, the separation means 27 forms a separation nip by a feed roller 27a that can be driven to rotate and a separation pad 27b that abuts on the feed roller 27a.

The feed roller 27a of the separating means 27 is in contact with the top recording sheet P in the sheet bundle in the sheet accommodating cassette 26. The feed roller 27a feeds the recording sheet P into the separation nip by its own rotational drive. When a plurality of recording sheets P are fed into the separation nip in a state of being overlapped with each other, the feed roller 27a comes into contact with only the highest recording sheet P among the recording sheets P. The uppermost recording sheet P moves in the feed direction in the separation nip following the surface movement of the feed roller 27a. On the other hand, the lower recording sheet P excluding the uppermost recording sheet P is provided with a load resistance by the separation pad 27b that does not move on the surface. As a result, the lower recording sheet P cannot move in the feeding direction following the uppermost recording sheet P, and stays in the separation nip. In this way, the separation means 27 separates only the highest recording sheet P out of the plurality of recording sheets P sent out from the sheet accommodating cassette 26 into one and directs it from the separation nip to the paper feed path. And send it out.

A transport roller pair 28 as a transport means is arranged near an intermediate point in the length direction of the paper feed path. The transport roller pair 28 forms a transport nip by bringing the first transport roller 28a as a transport member and the second transport roller 28b as a transport member into contact with each other. Of the two transfer rollers, at least the first transfer roller 28a is rotationally driven by the drive means.

Further, a resist roller pair 29 as a butt-conveying means is arranged near the end in the length direction of the paper feed path. The resist roller pair 29 includes a first resist roller 29a as a butt transfer member and a second resist roller pair 29b that abuts on the resist roller pair 29 to form a resist nip as a butt transfer nip. Of the two resist roller pairs, at least the first resist roller 29a is rotationally driven by the driving means.

The first transfer roller 28a of the transfer roller pair 28 is started to rotate at about the same time as the rotation drive of the feed roller 27a of the separation means 27 is started, or with a slight time lag. The tip of the recording sheet P sent out from the separation nip of the separation means 27 to the paper feed path is eventually sandwiched between the transfer nips of the transfer rollers vs. 28. Since the first transfer roller 28a is rotationally driven at a linear speed faster than that of the feed roller 27a, the recording sheet P is stretched with a strong tension between the separation nip and the transfer nip at this time. Then, when a strong torque is applied to the feed roller, the torque limiter operates and the feed roller is brought around to the recording sheet P. At this time, the torque limiter operates irregularly, so that the back tension is irregularly applied to the recording sheet P. Then, the recording sheet P slips on the first transport roller 28a, thereby promoting the wear of the first transport roller 28a.

After that, the recording sheet P is fed out from the inside of the transfer nip toward the resist roller pair 29 by the rotational drive of the first transfer roller 28a, and then the tip of the recording sheet P abuts against the resist nip of the resist roller pair 29. At this time, since the rotational drive of the resist roller pair 29 is stopped, the recording sheet P cannot enter the resist nip and gradually bends. This deflection corrects the skew of the recording sheet P.

After the recording sheet P starts to be sent out from the transport nip of the transport roller pair 28, the rotary drive of the feed roller 27a of the separation means 27 and the rotary drive of the transport roller pair 28 are stopped when a predetermined timing arrives. .. As a result, the recording sheet P is temporarily stopped in a state where the tip portion is bent.

An intermediate transfer unit 15 that allows the intermediate transfer belt 8 as an intermediate transfer body to be moved endlessly while being stretched is arranged above the image forming units 6Y, M, C, and K in the drawing. The intermediate transfer unit 15 includes an intermediate transfer belt 8, four primary transfer bias rollers 9Y, M, C, K, a cleaning device 10, and the like. It also includes a secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14, and the like.

The intermediate transfer belt 8 is stretched on three rollers inside the loop, and is endlessly moved counterclockwise in the drawing by rotational drive of at least one of the rollers. The primary transfer bias rollers 9Y, M, C, and K each form a primary transfer nip by sandwiching the intermediate transfer belt 8 which is endlessly moved in this way between the photoconductors 1Y, M, C, and K. These are of a method in which a transfer bias having the opposite polarity (for example, plus) to the toner is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All rollers except the primary transfer bias rollers 9Y, M, C, and K are electrically grounded. The intermediate transfer belt 8 sequentially passes through the primary transfer nips for Y, M, C, and K as it moves endlessly, and Y, M, C, on the photoconductors 1Y, M, C, and K, The K toner images are superimposed and primary 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 arranged inside the belt loop sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 arranged outside 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 recording sheet P by the secondary transfer nip. The transfer residual toner that has not been transferred to the recording sheet P is attached to the intermediate transfer belt 8 after passing through the secondary transfer nip. It is cleaned by the belt cleaning device 10.

After the rotational drive of the feed roller 27a and the transfer roller pair 28 is suspended, when the timing at which the recording sheet P can be synchronized with the four-color toner image on the intermediate transfer belt 8 in the secondary transfer nip comes, the feed roller 27a And the rotary drive of the transfer roller pair 28 is restarted. Further, the rotary drive of the resist roller pair 28 starts. As a result, after the recording sheet P is sandwiched between the resist nip of the resist roller pair 29, it is sent out from the resist nip toward the secondary transfer nip. Then, in the secondary transfer nip, it is superimposed on the four-color toner image on the intermediate transfer belt 8.

When the recording sheet P sent out from the secondary transfer nip passes between the rollers of the fixing device 20, the four-color toner image transferred to the surface is fixed by heat and pressure. After that, the recording sheet P is discharged to the outside of the machine through the space between the paper ejection rollers and the rollers 30. A stack portion 31 is formed on the upper surface of the printer main body, and the recording sheets P discharged to the outside of the machine by the paper ejection roller pair 30 are sequentially stacked on the stack portion 31.

A bottle container 33 is arranged between the intermediate transfer unit 15 and the stack portion 31 above the intermediate transfer unit 15. The bottle container 33 accommodates the toner bottles 32Y, M, C, and K as a replenishment toner accommodating portion for accommodating Y, M, C, and K toners. The toner bottles 32Y, M, C, and K are installed on the bottle container 33 so as to be placed from above for each color of toner. The Y, M, C, and K toners in the toner bottles 32Y, M, C, and K are appropriately replenished to the developing devices of the image forming units 6Y, M, C, and K by a toner replenishing device as a toner transporting means described later. Will be done. These toner bottles 32Y, M, C, and K can be attached to and detached from the printing unit 100 main body independently of the image forming units 6Y, M, C, and K.

A switchback device is arranged in the vicinity of the fixing device 20. In the double-sided print mode in which an image is formed on both sides of the recording sheet P, the recording sheet P that has passed through the fixing device 20 after the toner image is formed on only one side is turned upside down by this switchback device while being turned upside down by the resist roller. It is resent toward the resist nip of 29. Then, after being sent from the resist nip to the secondary transfer nip to form a toner image on the other surface, the fixing device 20 performs a fixing process on the toner image on the other surface, and then the paper ejection roller. It is stacked on the stack unit 31 via pair 30.

In FIG. 1, the image forming system according to the embodiment is shown from the front side. An image reading unit 200 including a scanner 201 and an ADF 251 is arranged on the print unit 100. The image reading unit 200 is fixed on a pedestal 199 supported by two legs fixed to the back surface of the printed portion 100, and is between the stack portion 31 of the printed portion 100 and the pedestal 199. There is a large space in between. The recording sheet P stacked on the stack portion 31 is located in that space.

The scanner 201 of the image reading unit 200 has a fixed reading unit 202 and a moving reading unit 203. The mobile reading unit 203 is arranged directly under the second contact glass fixed to the upper wall of the casing of the scanner 201 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 arranged on the left and right in the figure. Can be moved in the direction. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected on the surface of the document placed on the second contact glass, and then passed through a plurality of reflection mirrors. Then, the image reading sensor 204 fixed to the scanner body receives light.

On the other hand, the fixed reading unit 202 has a light source, a reflection mirror, an image reading sensor such as a CCD, and the like, and is directly below the first contact glass fixed to the upper wall of the casing of the scanner 201 so as to come into contact with the document MS. It is arranged. Then, when the document MS conveyed by the ADF251, which will be described later, passes over the first contact glass, the light emitted from the light source is sequentially reflected on the document surface and received by the image reading sensor via a plurality of reflection mirrors. To do. As a result, the first surface of the document MS is lightly scanned without moving the optical system including the light source and the reflection mirror. The ADF251, which will be described later, includes a second surface reading sensor that lightly scans the second surface of the document MS.

As shown in FIG. 3, the ADF 251 disposed on the scanner 201 is supported by a hinge 249 fixed to the scanner 201 so as to be swingable in the vertical direction. Then, the swing causes the movement like an opening / closing door to expose the first contact glass 211 and the second contact glass 212 on the upper surface of the scanner 201 in the opened state.

In the case of a single-bound original such as a book in which one corner of a bundle of originals is bound, the originals cannot be separated one by one, so that the ADF251 cannot convey the originals. Therefore, in the case of a single-bound original, after opening the ADF251 as shown in FIG. 3, the single-bound original with the page to be read is spread face down and placed on the second contact glass 212, and then the ADF251 is placed. Close. Then, the moving reading unit (203) of the scanner 201 is made to read the image of the page.

On the other hand, in the case of a bundle of originals in which a plurality of original MSs independent of each other are simply stacked, the original MSs are automatically conveyed one by one by the ADF251, and the fixed reading unit (202) in the scanner 201 or the first in the ADF251. It is possible to have the two-sided fixed reading unit read sequentially. In this case, after setting the document bundle on the document loading table 253, the copy start button is pressed. Then, the ADF 251 conveys the document MS of the document bundle placed on the document mounting table 253 in order from the top. In the process of this transfer, immediately after the original MS is inverted, the original MS is passed directly above the surface fixed reading unit (202) of the scanner 201. At this time, the image on the first surface of the original MS is read by the fixed scanning unit (202) of the scanner 201.

FIG. 4 is a configuration diagram showing the main configuration of the ADF 251 together with the upper portion of the scanner 201. The ADF251 includes a document setting unit A, a separate feeding unit B, an abutting unit C, a turn unit D, a transport unit E, a first reading and transporting unit F, a second reading and transporting unit G, a paper ejection unit H, a stacking unit I, and the like. It has.

The document setting unit A has a document placing table 253 or the like on which a bundle of document MSs is set. Further, the separate feeding unit B separates and feeds the original MS one by one from the bundle of the set original MS. Further, the abutting portion C abuts the tip of the fed document MS against the nip to correct the skew of the document MS, and conveys the corrected document MS to the turn portion D on the downstream side. is there. Further, the turn portion D has a curved transport portion that is curved in a C shape, and the original MS is turned upside down while being folded back in the curved transport portion. Further, the transport unit E corrects the skew of the document MS and transports the document MS toward the first reading transport unit F on the downstream side. Further, the first reading / conveying unit F conveys the document MS on the first contact glass 211, and the document is transferred to the fixed reading unit (202) arranged inside the scanner below the first contact glass 211. The first surface of the MS is read. Further, the second reading and conveying unit G causes the second surface reading sensor 295 to read the second surface of the document MS while conveying the document MS under the second surface reading sensor 295. Further, the paper ejection unit H ejects the document MS from which the images on both sides have been read toward the stack portion I. Further, the stack portion I stacks the document MS on the stack base 255.

FIG. 5 is a block diagram showing a main part of the electric circuit of the ADF251. A resist sensor 277, a document set sensor 263, a paper ejection sensor 261, an abutting sensor 271, a document width sensor 273, a reading inlet sensor 267, and the like are electrically connected to the controller 299 that controls the ADF 251. In addition, the table rise detection sensor 268, the bottom plate home position sensor 260, the second side reading sensor 295, the pickup motor 392, the paper feed motor 393, the reading motor 394, the paper ejection motor 395, the bottom plate rising motor 396, etc. are also electrically connected. .. Further, the lever detection sensor 364, the first length sensor 257, the second length sensor 258, and the like are also electrically connected.

In the document MS, the tip of the document is placed on the movable document table 254 that can swing in the directions of arrows a and b in the drawing according to the thickness of the bundle of the document MS, and the rear end of the document is placed on the document mounting table 253. It is set while it is placed on top. At this time, the position in the width direction is adjusted by abutting the side guides on both ends in the width direction (direction orthogonal to the drawing surface) on the document mounting table 253. The document MS set in this way is detected by the document set sensor 263 and pushes up the lever member 280 oscillatingly arranged above the movable document table 254. At this time, the lever detection sensor 364 (see FIG. 6) detects the lever member 280. Then, the document set sensor 263 and the lever detection sensor 364 transmit the detection signal to the controller 299. Then, this detection signal is sent from the controller 299 to the reading control unit of the scanner via the I / F.

The document mounting table 253 holds a first length sensor 257 and a second length sensor 258 made of a reflective photo sensor that detects the length of the document MS in the transport direction. These length sensors detect the length of the document MS in the transport direction, and send a detection signal to the controller 299.

Above the bundle of document MS placed on the movable document table 254, a pickup roller 259 that is movably supported in the vertical direction (arrows c and d in the figure) by a cam mechanism is arranged. .. This cam mechanism moves the pickup roller 259 up and down by driving the pickup motor. When the pickup roller 259 moves upward, the movable document table 254 swings in the direction of arrow a in the drawing, and the pickup roller 259 comes into contact with the top document MS in the bundle of document MS. Further, when the movable document table 254 rises, the table rise detection sensor 268 detects the rise of the movable document table 254 up to the upper limit. Based on this detection signal, the controller 299 stops the pickup motor 392 to stop the ascending of the movable document table 254.

For the main body operation unit including the numeric keypad and the display, the operator performs a key operation for setting a reading mode indicating whether it is a double-sided reading mode or a single-sided reading mode, or a copy start key pressing operation. When the copy start key is pressed, the document feeding signal is transmitted from the main body control unit 49 to the controller 299 of the ADF251. Then, the pickup roller 259 is rotationally driven by the forward rotation of the paper feed motor 393, and the document MS on the movable document table 254 is sent out from the movable document table 254.

Regarding the setting of the double-sided scanning mode or the single-sided scanning mode, it is possible to collectively set the double-sided and single-sided settings for all the document MSs placed on the movable document table 254. Further, the 1st and 10th original MSs are set to the double-sided scanning mode, while the other original MSs are set to the single-sided scanning mode, and so on. It is also possible to set.

The document MS sent out by the pickup roller 259 as a sending member enters the separation and conveying section B and is sent to the contact position with the paper feed belt 284. The paper feed belt 284 is stretched by a drive roller 282, a driven roller 283, and the like, and is endlessly moved in the clockwise direction in the drawing by the rotation of the drive roller 282 accompanying the forward rotation of the paper feed motor. The separation roller 285, which is rotationally driven clockwise in the drawing by the forward rotation of the paper feed motor 393, is in contact with the lower tension surface of the paper feed belt 284. At the contact portion, the surface of the paper feed belt 284 moves in the paper feed direction. On the other hand, the separation roller 285 is in contact with the paper feed belt 284 at a predetermined pressure, and when it is in direct contact with the paper feed belt 284, or only one original document MS is sandwiched in the contact portion. In that case, take it to the belt or the manuscript MS. However, when a plurality of original MSs are sandwiched between the contact portions, the rotating force is lower than the torque of the torque limiter, so that the original MS is rotationally driven clockwise in the figure opposite to the rotating direction. As a result, the separation roller 285 applies a moving force in the direction opposite to the paper feeding to the document MS below the top, and only the top document MS is separated from several sheets.

The document MS separated into one sheet by the action of the paper feed belt 284 and the separation roller 285 enters the abutting portion C. In the abutting portion C, the document MS abuts on the pullout nip due to the contact between the pullout driven roller 286 and the pullout driving roller 287 immediately after the tip portion thereof is detected by the abutting sensor 271. At this time, since the pull-out driven roller 286 and the pull-out drive roller 287 have stopped rotational driving, the document MS cannot enter the pull-out nip. Therefore, it gradually bends with transportation. The skew of the original MS is corrected by the bending force.

After that, the controller 299 rotationally drives the pull-out drive roller 287 to send out the document MS from the pull-out nip and sends it to the turn portion D on the downstream side. Since the linear velocity of the pull-out drive roller 287 is faster than the linear velocity of the paper feed belt 284 on the upstream side, the document MS is stretched with a strong tension between the separation nip and the pull-out nip. Then, since a strong torque is applied to the paper feed belt 284, the torque limiter operates and the drive roller 282 driving the paper feed belt 284 is brought around to the document MS.

The document MS sent out from the transport nip toward the turn portion D passes directly under the document width sensor 273. The document width sensor 273 has a plurality of paper detection units (swing levers described later) arranged in a direction orthogonal to the paper surface in the figure, and these paper detection units are in the document width direction (direction orthogonal to the paper surface). Lined up in. The size of the original MS in the width direction is detected based on which paper detection unit detects the original MS.

The tip of the document MS whose size in the width direction is detected by the document width sensor 273 enters the turn portion D. The turn portion D as a transport portion forms a turn transport nip by contact between the first turn roller 266 and the second turn roller 273. The document MS sandwiched between the turn transfer nips is conveyed toward the downstream transfer unit E by the first turn roller 266 which is rotationally driven by the paper feed motor. At this time, the top and bottom are turned upside down by advancing along the curved portion of the transport path 315. Even on the surface of the first turn roller 266, the original MS slips due to the back tension, so that the wear of the first term roller 266 is promoted.

The document MS sent out from the turn transport nip toward the transport section E passes through the position facing the reading inlet sensor 267 and then reaches the transport section E. The transport unit E forms a transport nip by abutting the first transport roller 289 and the second transport roller 290. The document MS that has passed the position facing the reading inlet sensor 267 has its tip inserted into the transport nip immediately after being detected by the resist sensor 277. Then, the document MS that has passed through the transport nip passes through the first reading and transporting unit F while being pressed against the first contact glass 211 of the scanner 201 by the pressing roller 265. At this time, the image of the first surface (the surface facing downward in the drawing) of the document MS is read by the first fixed reading unit 202 of the scanner 201.

The tip of the document MS that has passed through the first reading and transporting unit F is detected by the paper ejection sensor 261 after passing through the reading outlet roller pair 292 described later. When the single-sided reading mode is set, it is not necessary to read the second side of the document MS by the second-sided reading sensor 295, which will be described later. Therefore, when the tip of the original MS is detected by the paper ejection sensor 261, the forward rotation drive of the paper ejection motor is started, and the paper ejection roller on the lower side in the drawing of the paper ejection roller pair 294 moves clockwise in the drawing. It is driven to rotate. The drive of the paper ejection motor is stopped at the timing when the rear end of the document MS comes out of the nip of the paper ejection roller vs. 294.

On the other hand, when the double-sided scanning mode is set, the timing from the detection of the tip of the document MS by the paper ejection sensor 261 to the arrival at the second surface scanning sensor 295 is based on the pulse count of the scanning motor. It is calculated. Then, at that timing, the controller 299 transmits a gate signal indicating an effective image region in the sub-scanning direction on the second surface of the document MS to the scanning control unit of the scanner 201. This transmission is continued until the rear end of the document MS exits the reading position by the second surface reading sensor 295, and the image of the second surface of the document MS is read by the second surface reading sensor 295.

The second surface reading sensor 295 comprises a close contact image sensor (CIS). A second reading roller 296 that supports the document MS from the non-reading surface side is arranged at a position facing the second surface reading sensor 295. The second scanning roller 296 serves to prevent the document MS from floating at the scanning position by the second surface scanning sensor 295 and to function as a reference white portion for acquiring shading data in the second surface scanning sensor 295. I am in charge.

FIG. 6 is a block diagram showing a main part of the electric circuit of the second surface reading sensor 295 together with the controller 299 and the main body control unit 49. In the figure, the second surface reading sensor 295 has a light source unit F01 including an LED array, a fluorescent lamp, a cold cathode tube, and the like. Further, a plurality of sensor chips F02 arranged in the main scanning direction (direction corresponding to the document width direction), a plurality of OP amplifier circuits F03 individually connected to each sensor chip F02, and individually connected to each OP amplifier circuit F03. It also has a plurality of A / D converters F04. Further, it also has an image processing unit F05, a frame memory F06, an output control circuit F07, an I / F circuit F08, and the like.

The sensor chip F02 includes a photoelectric conversion element called a 1x contact image sensor and a condenser lens. Prior to the document MS entering the reading position by the second surface reading sensor 295, the lighting ON signal is sent from the controller 299 to the light source unit F01. As a result, the light source unit F01 is turned on, and the light is directed toward the second surface of the document MS. The reflected light reflected by the second surface of the original MS is collected by the photoelectric conversion element by the condenser lens in the plurality of sensor chips F02 and read as image information. The image information read by each sensor chip F02 is amplified by the OP amplifier circuit F03 and then converted into digital image information by the A / D converter F04. These digital image information are input to the image processing unit F05, shading correction and the like are performed, and then temporarily stored in the frame memory F06. After that, it is converted into a data format that can be accepted by the main body control unit 49 by the output control circuit F07, and then output to the main body control unit 49 via the I / F circuit F08.

From the controller 299, a timing signal for notifying the timing when the tip of the document MS reaches the reading position by the second surface reading sensor 295 (image data after that timing is treated as valid data), a lighting signal of the light source, Power supply etc. is output.

Mode information for setting the copy operation mode to the normal mode or the silent mode can be input to the operation display unit 48 of the print unit 100. When the mode information is input to the operation display unit 48, the main body control unit 49 sets the copy operation mode to correspond to the input mode information, and transfers the mode information to the controller 299 of the ADF 51. When the mode information is transferred, the controller 299 sets the copy operation mode to the one corresponding to the input mode information.

When the copy operation mode is set to the normal mode, the main body control unit 49 sets the transport speed (process linear speed) of the recording sheet in the print unit 100 to a predetermined standard speed, and corresponds to the standard speed. Drives various motors at the driving speed. As a result, the printing unit 100 conveys the recording sheet at high speed. On the other hand, when the copy operation mode is set to the silent mode, the transport speed of the recording sheet in the printing unit 100 is set to a speed slower than the standard speed. As a result, in the silent mode, the recording sheet is conveyed at a speed slower than the standard speed, thereby suppressing the generation of noise.

When the copy operation mode is set to the normal mode, the controller 299 of the ADF 51 sets the transport speed of the document MS in the ADF 51 to a predetermined reference speed, and drives various motors at a drive speed corresponding to the reference speed. Drive. As a result, the document MS is conveyed at high speed in the ADF 51. On the other hand, when the copy operation mode is set to the silent mode, the transport speed of the document MS in the ADF 51 is set to a speed slower than the reference speed. As a result, in the silent mode, the original MS is conveyed at a low speed slower than the reference speed, thereby suppressing the generation of noise.

The separate feeding section B, the abutting section C, the turn section D, the transport section E, the first reading transport section F, the second reading transport section G, and the paper ejection section H are covered with the feed cover 298. In the feed cover 298, a transport path 315 for transporting the original MS (original sheet), which is a sheet material, is formed by a plurality of guide plates. The inlet side portion of the transport path 315 in the sheet transport direction is formed between the feed guide upper plate 300 and the feed guide lower plate 301. Further, the central portion of the transport path 315 in the sheet transport direction is formed between the side guide plate 302 and the metal guide plate 303. In the process of transporting the document MS in those transport paths 315, rubbing noise and bumping noise are generated.

FIG. 7 is a diagram showing the transport path 315 and its surroundings immediately after the document MS is brought into the abutting portion C. In the abutting portion C, as shown in the figure, in order to correct the skew of the document MS, the document being conveyed with respect to the pullout nip due to the contact between the pullout drive roller 287 that is not rotationally driven and the pullout driven roller 286. Hit the tip of the MS. At this time, a bumping sound is generated.

FIG. 8 is a diagram showing a transport path 315 and its surroundings in a state where the transport of the document MS at the abutting portion C is temporarily stopped. In the abutting portion C, in order to correct the skew of the original MS, the original MS is bent to some extent by continuing to convey the original MS in a state of being abutted against the pull-out nip, thereby bending the original MS as shown in the figure. At this time, by rubbing the bent document portion against the feeding guide lower plate 301, a rubbing noise is generated.

FIG. 9 is a diagram showing the transport path 315 and its surroundings immediately after resuming the transport of the document MS at the abutting portion C. A document width sensor 273 is arranged in the vicinity of the nip on the downstream side in the sheet transport direction from the pull-out nip. The document width sensor 273 includes a plurality of swing levers arranged in a direction orthogonal to the paper surface (corresponding to the document width direction) in the figure. In a state where the document MS does not exist on the downstream side in the sheet transport direction from the pull-out nip, the free end side of the swingable swing lever penetrates the transport path 315 from the upper side to the lower side. When the tip of the document MS being conveyed swings toward the free end side of the swing lever, the posture of the swing lever is changed by pushing the free end side in the sheet transport direction while advancing. By detecting this change in posture, the document MS is detected. The document MS changes the posture of the swing levers while contacting the number of swing levers corresponding to the size in the width direction of the plurality of swing levers. At the initial stage of this process, the tip of the document MS abuts on the swing lever as shown in the drawing, thereby generating a butt sound.

FIG. 10 is a diagram showing a transport path 315 and its surroundings in a state where the document MS is being transported in the turn portion D. As described above, the document MS is conveyed in the turn section D at a higher speed than the separate feeding section B. At this time, the document MS moves at high speed while rubbing against the feed guide upper plate 300 and the side guide plate 302 in a bent posture as shown in the drawing. At this time, a rubbing noise between the document MS and the guide plate is generated.

The bumping noise and the rubbing noise generated in the transport path 315 may be transmitted to the feed cover 298 as vibration and then reach the outside as noise.

FIG. 11 is a configuration diagram showing an ADF 51 in a state where the feed cover unit 390 is opened. In the figure, the paper feed cover unit 390 is composed of a feed guide upper plate 300, a reading inlet sensor 267, a first turn roller 266, a document width sensor 273, a pullout driven roller 286, a butt sensor 271, and the like. While these components are held by a common holding body, they are supported by the main body frame so as to swing around a swing shaft 389 provided on the metal main body frame. As shown in the figure, the feed cover unit 390 is moved counterclockwise in the drawing around the swing shaft 389, and the feed guide upper plate 300 is fixed to the main body frame side. The inside of the transport path 315 can be exposed at a large distance from the 301. This makes it possible to easily take out the jam original in the transport path 315.

Next, a characteristic configuration of the image forming system according to the embodiment will be described.
In FIG. 4, for convenience, the structure of the feed cover 298 is shown in a simplified manner, but the feed cover 298 is composed of a plurality of members as shown in FIG. The outer cover 298a, the claw 298b, the claw 298c, the inner cover 298d, and the like. The outer cover 298a is arranged on the outside so as to come into contact with the outside air, while the inner cover 298d is arranged on the inside so as to swing to the inside air. The paper feed cover 298 has a double structure in which a gap is formed between the outer cover 298a and the inner cover 298d.

The outer cover 298a is integrally formed with a claw 298b and a claw 298b as hooking portions to be hooked on the inner cover 298d. The outer cover 298a is held by the inner cover 298d by hooking the claws 298b and 298c on the inner cover 298d as shown in the drawing. In such a configuration, the outer cover 298a can be attached to and detached from the inner cover 298d without using a tool.

The double-structured paper feed cover 298, which forms a gap between the outer cover 298a and the inner cover 298d, has the same principle as the double sash, and has a sound generated inside as compared with the one having a single structure. It is possible to suppress transmission to the outside. Therefore, it is possible to reduce the noise caused by the rubbing noise and the bumping noise generated in the transport path 315.

Next, an example in which a more characteristic configuration is added to the image forming system according to the embodiment will be described. Unless otherwise specified below, the configuration of the image forming system according to the embodiment is the same as that of the embodiment.

A system in which the claw 298b or the claw 298c is hooked on the inner cover 298d and the outer cover 298a is attached to the inner cover 298d as in the image forming system according to the embodiment has the following merits. That is, the outer cover 298a can be attached to and detached from the inner cover 298d without using a tool, and the assembling property and maintainability can be improved. On the other hand, the vibration of a vibration source such as a motor may cause the outer cover 298a to rattle with respect to the inner cover 298d, causing noise due to rattling noise. In particular, in the configuration in which the feed cover unit 390 is oscillatingly held to remove jam documents as in the embodiment, the entire feed cover unit 390 tends to vibrate, so that noise due to rattling noise is generated. Easy to do.

FIG. 12 is a diagram showing an outer cover 298a of the paper feed cover 298 in the ADF251 of the image forming system according to the embodiment. A soft elastic member 298e is attached to the inner surface of the paper feed cover 298 with double-sided tape.

FIG. 13 is a diagram showing ADF251 of the image forming system according to the embodiment. As shown in the figure, the soft elastic member 298e attached to the inner surface of the outer cover 298a is sandwiched between the outer cover 298a and the inner cover 298d and is compressed and deformed. Then, the restoring force that tries to return to the original shape presses the claw 298b integrally formed on the outer cover 298a and the hooked portion of the claw 298c with respect to the inner cover 298d toward the inner cover 298d. By suppressing the rattling of the outer cover 298a by this pressing, the noise due to the rattling noise can be reduced.

As the soft elastic member 298e, a member made of a sponge which is a porous material is used. In such a configuration, the plurality of air bubbles provided in the soft elastic member 298e absorb the bumping sound and the rubbing sound generated in the transport path 315, so that the noise caused by them can be further reduced. The inner cover 298a is provided with a plurality of ribs extending in the left-right direction in the drawing in order to increase the mechanical strength. The inner surface of the inner cover 298a is partitioned by these ribs in the depth direction in the drawing, and a soft elastic member 298e is attached to each partition region. Therefore, the soft elastic member 298e is present in most of the gaps between the outer cover 298a and the inner cover 298d to enhance the sound absorbing effect.

Although an example in which the present invention is applied to the ADF 251 has been described so far, the present invention is applied to a printing unit 100 or a post-processing device (for example, a binding device) provided with a sheet transport device for transporting a recording sheet P which is a sheet material. You may.

What has been described above is an example, and has a unique effect in each of the following aspects.
[Aspect A]
Aspect A is a sheet transport device (for example, ADF251) having a transport path (for example, transport path 315) for transporting a sheet material (for example, document MS) and an exterior cover (for example, feed cover 298) for covering the transport path. The exterior cover is characterized in that a gap is formed between an inner member (for example, the inner cover 298d) that comes into contact with the internal air and an outer member (for example, the outer cover 298a) that comes into contact with the outside air. is there.

In the aspect A, in order for the rubbing noise and the bumping noise generated in the transport path in the exterior cover to reach the user's ear as noise, the inner member of the exterior cover, the air in the void, and the outer member of the exterior cover. It is necessary to transmit the air outside the aircraft in that order. In such sound transmission, the number of times the sound is transmitted is increased and the volume is attenuated due to the transmission, as compared with the conventional sheet transport device that is transmitted only to the one-piece exterior cover and the air outside the machine and reaches the user's ear. Since the number of times is increased, the volume when it finally reaches the user's ear is reduced. Therefore, it is possible to reduce the noise caused by the rubbing noise and the bumping noise generated in the transport path.

[Aspect B]
In aspect B, in aspect A, one of the inner member and the outer member is provided with a hooking portion (for example, claw 298b, claw 298c) to be hooked on the other, and the outer member is attached to the inner member by the hooking of the hooking portion. It is characterized by being retained. In such a configuration, the outer member can be attached to and detached from the inner member without using a tool, and the assembling property and maintainability of the outer member can be improved.

[Aspect C]
Aspect C is characterized in that, in aspect B, a soft elastic member (for example, a soft elastic member 298e) that is sandwiched between the inner member and the outer member and deforms by compression is provided in the gap. In such a configuration, the restoring force that tries to return to the original shape of the compression-deformed soft elastic member presses the outer member against the inner member to suppress the rattling of the outer member, so that the noise due to the rattling noise can be reduced. ..

[Aspect D]
Aspect D is characterized in that, in Aspect C, a material made of a porous material is used as the soft elastic member. In such a configuration, the plurality of air bubbles provided in the soft elastic member absorb the bumping sound and the rubbing sound generated in the transport path, so that the noise caused by them can be further reduced.

[Aspect E]
Aspect E is an image reading means (for example, scanner 201) for reading an image of a document (for example, document MS) and a sheet transporting means (for example, a sheet transporting means) for transporting a document sheet (for example, document MS) as a sheet material to an image reading position by the image reading means. For example, in an image forming system including an ADF251) and an image forming means (for example, a printing unit 100) for forming an image on a recording material (for example, a recording sheet P), any one of aspects A to D is used as the sheet conveying means. It is characterized by being there.

P: Recording sheet (sheet material)
MS: Manuscript (sheet material)
100: Printed portion (image forming means)
201: Scanner (image reading means)
251: ADF (Sheet Transfer Device)
298: Feeding cover (exterior cover)
298a: Outer cover (outer member)
298b: Claw (hook)
298c: Claw (hook)
298d: Inner cover (inner member)
298e: Soft elastic member 315: Transport path

Patent No. 4588665

Claims (3)

In a sheet transport device having a pair of guide plates that sandwich a transport path for transporting a sheet material and an exterior cover that covers the pair of guide plates.
The exterior cover has a structure in which a gap is formed between an inner member facing the pair of guide plates and an outer member in contact with the outside air .
One of the inner member and the outer member is provided with a hooking portion for being hooked on the other, and a soft elastic member that is sandwiched between the inner member and the outer member in the gap and is compressively deformed.
A sheet transporting device characterized in that the outer member is held by the inner member by being caught by the hooked portion by a restoring force from compression of the soft elastic member . In the sheet conveying apparatus請Motomeko 1,
A sheet transfer device characterized in that a material made of a porous material is used as the soft elastic member. In an image forming system including an image reading means for reading an image of a document, a sheet transporting means for transporting a document sheet as a sheet material to an image reading position by the image reading means, and an image forming means for forming an image on a recording material.
An image forming system characterized in that the sheet transport device according to claim 1 or 2 is used as the sheet transport means.

Images