JP6387691B2 - Sheet conveying apparatus, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that continuously conveys sheets, an image reading apparatus including the sheet conveying apparatus, and an image forming apparatus.

  In an image reading apparatus used in an image forming apparatus such as a scanner, a facsimile machine, a copying machine, etc., an automatic document conveying device, which is a sheet conveying device, is provided for continuously reading an original from a bundle of originals into an image reading unit. It has been. Some automatic document feeders include a cover member that can be rotated and opened for jamming and maintenance of documents.

  Such a rotatable cover member provided in the sheet conveying apparatus is not a simple exterior cover, but is often provided with various guides, rollers, sensors and the like inside the exterior cover. That is, the cover member includes a conveyance guide serving as a conveyance surface on one side in the paper conveyance path, a driven roller (hereinafter referred to as a driven roller) in a pair of conveyance rollers required in the paper conveyance path, and a coil spring for pressurizing the driven roller. And the like, a sensor for detecting the position of the paper during paper conveyance, a support member for supporting the driven roller, the elastic member, the sensor, and the like, or a reinforcing member for the conveyance guide.

  When each of these parts and members has a metal part, static electricity is generated due to friction between the sheet and the conveyance guide during conveyance of the sheet, friction between the driven roller shaft and the bearing, and the like. And, due to this static electricity, electromagnetic noise is generated from the metal part, and there is a risk of affecting surrounding electronic devices and human bodies. In order to cope with this, it is necessary to connect a component having a metal part to the ground and ground it (ground floating metal).

  In most cases, the equipment ground is set on the body frame, so screw the ground wire at both ends from the metal part located inside the rotatable cover to the nearest body frame at both ends. Often fixed and connected.

  In Patent Document 1, since the floating metal on the rotatable cover side is grounded with a simple configuration without twisting the ground wire, the cover member can be opened and closed in correspondence with the opening of the image forming apparatus. A magnet catch that is a magnetic force adsorbing member disposed in the opening and a means for adsorbing the magnet to the cover member are provided to constitute a fixed holding means, and the main body frame is covered with the fixed holding means. A grounding device is described in which the conductive state of both members is set with the members fixed.

  In this installation, a magnet provided at a fixed position and a retractable yoke member are arranged with respect to the holding member provided on the magnet catch, and the yoke member is disposed in a protruding direction via a conductive elastic member. The bracket disposed on the cover member in correspondence with the magnet catch is configured as a member that conducts with the cover member.

  However, since the ground wire must pass between the main body frame and the rotatable cover that can move with respect to the main body frame, either the tension is applied to the ground wire due to the rotation of the cover, or one of the scooping routes There is a concern that the part may be rubbed or broken or broken. In order to cope with this, when a protective member is provided on the ground wire or a metal member that is grounded on the main body frame is provided as a separate member, the number of components is increased, resulting in a complicated structure and an increase in product cost.

  Further, Patent Document 1 also has a large number of components and is complicated, resulting in an increase in cost. Furthermore, since the yoke member is urged in the protruding direction via the elastic member having conductivity, it is excellent that the accuracy of the alignment of the landing portion is unnecessary, but on the other hand, the position in the urging direction is It becomes unstable. That is, the outer surface of the cover having such a configuration does not match another cover outer surface, a step is generated, and the appearance quality is deteriorated. Furthermore, when the paper conveyance guide surface or one side of the conveyance roller pair is provided inside, the desired position of the conveyance guide surface and the desired pressure of the conveyance roller pressure cannot be obtained, and the desired conveyance quality cannot be obtained. Or when the outer surface of the cover is pushed in or pulled outward, the elastic member moves by the biasing force, and the quality of operation is deteriorated.

  Therefore, the present invention provides a simple structure that reliably grounds the floating metal in the cover without reducing the holding position accuracy and without fear of the ground wire being damaged or cut. Objective.

A sheet conveying apparatus according to the present invention includes a body frame, and a cover unit which is releasably arranged movable relative to the body frame, provided in the cover unit, the magnet member and the yoke member, the body frame to a magnetic lifting member that holds the closed state of the cover unit are adsorbed by magnetic force, in contact with the yoke member, it includes a conductive member which conducts the arranged metal member within the cover unit, wherein In the sheet conveying apparatus in which the metal member in the cover unit is in conduction with the main body frame when the cover unit is in a closed state, a protrusion is formed on one of the cover unit and the yoke member, and a hole is formed on the other. The yoke member is directly fixed to the cover unit by fitting the protrusion into the hole.

  According to the present invention, the floating metal in the cover can be securely grounded with a simple configuration without damaging or cutting the ground wire without deteriorating the holding position accuracy of the rotatable cover. .

1 is a diagram illustrating a schematic configuration of an image forming apparatus to which the present invention is applied. Sectional view of a sheet conveying apparatus to which the present invention is applied Block diagram showing the main part of the control system of the sheet conveying apparatus The block diagram which shows the principal part of the electric circuit of the 2nd reading part of the sheet conveying apparatus Sectional drawing which shows the opening-and-closing state of the paper feed cover unit in the sheet conveying apparatus The figure which shows the structure of the magnet catch which concerns on Embodiment 1 and Embodiment 2 of the sheet conveying apparatus The figure which shows the attachment state of the magnet catch The figure which shows the magnet catch which concerns on Embodiment 3 of the same sheet conveying apparatus. The figure which shows the magnet catch which concerns on Embodiment 4 of the same sheet conveying apparatus. The figure which shows the attachment state of the magnet catch

  Hereinafter, a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus according to embodiments for carrying out the present invention will be described. First, a basic configuration of the image forming apparatus according to the embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus to which the present invention is applied. The image forming apparatus 300 according to the embodiment is a copying machine including an image reading apparatus that automatically conveys the document 1 and reads the document 1. The image forming apparatus 300 includes an image forming unit 310 as an image forming unit, a transfer paper feeding device 340, and an image reading unit 350. An image reading unit 350 as an image reading apparatus includes a scanner unit 370 fixed on the image forming unit 310, and an automatic document conveying device 400 as a sheet conveying device arranged on the scanner unit 370. It is configured.

  The transfer paper feeding device 340 separates the transferred transfer paper from the two transfer paper feeding cassettes 342 and 342 arranged in the paper feeding unit 341 and feeds the transfer paper as a recording medium. A transfer paper separation roller 345 that supplies the transfer paper to the transfer paper feed path 344 is provided. The transfer paper feeding device 340 feeds the transfer paper in the transfer paper feed cassette 342 into the main body side transfer paper feed path 337 in the image forming unit 310.

  The image forming unit 310 includes an optical writing device 302, four process units 303K, 303Y, 303M, and 303C, a transfer unit 324, a paper transport unit 328, a positioning roller pair (registration roller pair) 333, a fixing device 334, and the like. The image forming unit 310 also includes a switchback device 336 and a main body side transfer paper feed path 337. The process units 303K, 303Y, 303M, and 303C include photoconductors 304K, 304Y, 304M, and 304C, respectively. The process units 303K, 303Y, 303M, and 303C respectively create black (K), yellow (Y), M (magenta), and C (cyan) toner images.

  The optical writing device 302 drives a light source such as a laser diode (not shown) or an LED (Light Emitting Diode) disposed inside to irradiate the four photosensitive members 304K, 304Y, 304M, and 304C with laser light. . The optical writing device 302 controls the laser light applied to each of the photoconductors 304K, 304Y, 304M, and 304C based on the image data of the document 1 read by the image reading unit 350. By this irradiation, electrostatic latent images are formed on the surfaces of the photoreceptors 304K, 304Y, 304M, and 304C, and the latent images are developed into toner images via a predetermined development process, and are written on both sides of the document 1. The copied image is copied onto the transfer paper.

  The process units 303K, 303Y, 303M, and 303C are configured by supporting the photoconductors 304K, 304Y, 304M, and 304C and various devices disposed around the process units as a single unit on a common support. . These can be attached to and detached from the image forming unit 310 of the image forming apparatus main body. The process units 303K, 303Y, 303M, and 303C are configured by arranging a charging device, a developing device, a drum cleaning device, a static elimination lamp, and the like around the photoreceptors 304K, 304Y, 304M, and 304C. The image forming apparatus 300 has a so-called tandem type configuration in which four process units 303K, 303Y, 303M, and 303C are arranged so as to face the intermediate transfer belt 325 along the endless movement direction.

  A transfer unit 324 is disposed below the process units 303K, 303Y, 303M, and 303C. The transfer unit 324 moves the intermediate transfer belt 325 stretched by a plurality of rollers endlessly in the clockwise direction in the drawing while contacting the photoreceptors 304K, 304Y, 304M, and 304C. As a result, primary transfer nips for K, Y, M, and C in which the photoconductors 304K, 304Y, 304M, and 304C contact the intermediate transfer belt 325 are formed. In the vicinity of the primary transfer nips for K, Y, M, and C, the intermediate transfer belt 325 is pressed toward the photoconductors 304K, 304Y, 304M, and 304C by a primary transfer roller disposed inside the belt loop.

  A primary transfer bias is applied to these primary transfer rollers by a power source (not shown). As a result, a primary transfer electric field for electrostatically moving the toner images on the photoconductors 304K, 304Y, 304M, and 304C toward the intermediate transfer belt 325 is formed in the primary transfer nips for K, Y, M, and C. Yes. In the drawing, toner images are sequentially transferred from the primary transfer nip to the front surface of the intermediate transfer belt 325 that sequentially passes through the primary transfer nips for K, Y, M, and C along with the endless movement in the clockwise direction. Overlaid and primary transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) is formed on the front surface of the intermediate transfer belt 325.

  A paper transport unit 328 including a paper transport belt 329 is provided below the transfer unit 324 in the drawing. As a result, a secondary transfer nip is formed in which the front surface of the intermediate transfer belt 325 and the front surface of the paper transport belt 329 are in contact with each other.

  A positioning roller pair 333 is disposed on the right side of the secondary transfer nip in the drawing. A sensor (not shown) is disposed near the entrance of the nip portion of the positioning roller pair 333. The transfer paper conveyed from the transfer paper feeding device 340 toward the positioning roller pair 333 is temporarily stopped after a predetermined time when the leading edge of the transfer paper is detected by a sensor (not shown), and the nip between the positioning roller pair 333 is detected. Put the tip against the part. As a result, the posture of the transfer paper is corrected, and preparations for synchronization with image formation are completed.

  When the transfer paper prior application hits the nip portion, the positioning roller pair 333 resumes roller rotation driving at a timing at which the transfer paper can be synchronized with the four-color toner image on the intermediate transfer belt 325, and the transfer paper is transferred to the secondary. Send to transfer nip. In the secondary transfer nip, the four-color toner image on the intermediate transfer belt 325 is secondarily transferred onto the transfer paper under the influence of the secondary transfer electric field and the nip pressure, and becomes a full color image combined with the white color of the transfer paper. The transfer paper that has passed through the secondary transfer nip is separated from the intermediate transfer belt 325 and is conveyed to the fixing device 334 along with its endless movement while being held on the front surface of the paper conveyance belt 329.

  The transfer paper conveyed to the fixing device 334 is fixed to a full color image by pressure or heating in the fixing device 334 and then sent from the fixing device 334 to the paper discharge roller pair 335, and then a paper discharge tray outside the apparatus. It is discharged to 301.

  In FIG. 1, a switchback device 336 that is a transfer paper reversing device is disposed below the paper transport unit 328 and the fixing device 334. Thereby, the images on both sides of the document 1 read by the image reading unit 350 can be printed on both sides of the transfer paper. When performing double-sided printing, the transfer path of the transfer paper that has undergone image fixing processing on one side is switched to the switchback device 336 side by the switching claw, where the transfer paper is reversed and enters the secondary transfer nip again. . Then, the second transfer process and the fixing process of the image are also performed on the other side of the transfer sheet, and then the sheet is discharged onto the discharge tray 301.

  An image reading unit 350 including a scanner unit 370 on the image forming unit 310 and an automatic document feeder 400 on the scanner unit 370 includes a first reading unit 20 and a second reading unit 25 which are fixed reading units to be described later, A fixed reading unit and a moving reading unit 372 are provided. The movable reading unit 372 is disposed immediately below the second contact glass 371 fixed to the upper wall of the casing of the image reading unit 350 so as to come into contact with the document 1, and illustrates an optical system including a light source, a reflection mirror, and the like. It can be moved in the middle / left / right direction. Then, in the process of moving the optical system from the left side to the right side in the drawing, the light emitted from the light source is reflected by the lower surface of the document 1 disposed on the second contact glass 371 and then passes through a plurality of reflecting mirrors. Then, the light is received by the image reading sensor 373 fixed to the image reading unit 350.

  On the other hand, the image reading unit 350 includes a first reading unit 20 disposed in the scanner unit 370 and a second reading unit 25 disposed in the automatic document feeder 400 as fixed reading units. The first reading unit 20, which is an image reading unit having a light source, a reading sensor such as a CIS, is disposed directly below the first contact glass 123 fixed to the upper wall of the casing of the scanner unit 370 so as to contact the document 1. ing. Then, when the document 1 transported by the automatic document transport device 400 passes through the first contact glass 123, the image is read by reflection of light emitted from the light source on the first surface of the document 1. The second reading unit 25 that is an image reading unit reads the second surface of the document 1 after passing through the first reading unit 20.

  Hereinafter, the sheet conveying apparatus will be described. The sheet conveying apparatus according to the present invention includes a magnet catch on the rotatable cover unit side when the cover that can rotate with respect to the main body frame is held by a magnet catch that is a magnetic adsorption member. Then, the magnet catch is directly fixed to the cover unit, and the floating metal in the cover unit is electrically connected to the magnet catch inside the cover.

  Next, the sheet conveying apparatus will be described. FIG. 2 is a sectional view of a sheet conveying apparatus to which the present invention is applied, and FIG. 3 is a block diagram showing a main part of a control system of the sheet conveying apparatus.

  An automatic document conveying device 400, which is a sheet conveying device, includes an original setting unit A, a separation conveying unit B, a positioning unit C, a turn unit D, a first reading conveying unit E, a second reading conveying unit F, a paper discharging unit G, and A stack portion H is provided. In the document setting portion A, a read document bundle that is a bundle of sheets is set. The separation conveyance unit B separates and conveys the originals one by one from the original bundle set in the original setting unit A. The positioning unit C performs the primary abutting alignment of the conveyed document 1 and pulls out and conveys the aligned document. The turn part D turns the document 1 being conveyed and conveys the document surface toward the reading side (downward). The first reading conveyance unit E causes the surface image of the document 1 to be read from below the first contact glass 123. The second reading conveyance unit F reads the back image of the original 1 after reading. The paper discharge unit G discharges the original 1 whose front and back have been read out of the apparatus. The stack unit H stacks and holds the document 1 after the reading is completed. In addition, the automatic document feeder 400 includes drive units described later that drive these transport operations, and a controller unit 100 that controls a series of operations.

  As shown in FIG. 3, the controller unit 100 is connected to a main body control unit 111 that controls the entire image forming apparatus 300, and a main body operation unit 108 is connected to the main body control unit 111. The controller unit 100 includes a set sensor 5, a bottom home position sensor 6, an appropriate position sensor 8, an abutment sensor 11, a document width sensor 13, a reading entrance sensor 15, a positioning sensor 17, a paper discharge sensor 24, and a second reading. The unit 25 and document length detection sensors 30, 31, and 32 are connected. Further, the controller 100 is connected to the pickup lifting / lowering motor 101, the paper feeding motor 102, the reading motor 103, the paper discharging motor 104, the bottom plate raising motor 105, the pull-out motor 113, and the reading inlet motor 114 as the driving units described above.

  First, the document setting unit A will be described. A bundle of documents 1 to be read is set on a document table 2 including a movable table 3. The document 1 is set with the document surface facing upward. Further, the document 1 is positioned in a direction perpendicular to the conveyance direction by a side guide (not shown). The set document 1 is detected by the set filler 4 and the set sensor 5, and the fact is transmitted to the main body control unit 111 by the I / F circuit 107 described later. Further, an outline of the length in the document transport direction is determined by the document length detection sensors 30 and 31 provided on the surface of the document table 2. Here, as the document length detection sensors 30 and 31, a reflection type sensor or an actuator type sensor that can detect even one document is used. Further, the document length detection sensors 30 and 31 are arranged so as to be able to determine at least whether the document size is vertical or horizontal.

  The movable table 3 is moved up and down by the bottom plate raising motor 105 in the directions a and b shown in the drawing. When the set filler 4 and the set sensor 5 detect that the original 1 is set, the bottom plate raising motor 105 is rotated forward, and the movable table 3 is raised so that the uppermost surface of the original bundle contacts the pickup roller 7.

  The proper position sensor 8 detects that the bottom plate is raised too much and detects that the upper surface of the document bundle is maintained at an appropriate paper feed height. When the appropriate position sensor 8 is turned on, the ascent of the movable table 3 is stopped. When the upper surface position of the original document is lowered by repeating this paper feeding and the proper paper feed position sensor is turned off, the control is repeated so that the movable table 3 is raised and the proper position sensor 8 is turned on again. Is maintained at a height suitable for paper feeding.

  When all the set documents are fed, the movable table 3 is lowered to the home position so that the bottom plate raising motor 105 can be reversed to set the next bundle of documents.

  The pickup roller 7 is operated by the pickup lifting / lowering motor 101 in the c and d directions in FIG. 2 via the cam mechanism, and the movable table 3 is lifted and pushed by the upper surface of the document on the movable table 3 to be raised in the c direction. The upper limit can be detected by the appropriate position sensor 8. When the main body operation unit 108 designates the duplex mode or the single side mode by pressing a key and then the print key is pressed, a document feed signal is transmitted from the main body control unit 111 to the controller unit 100 via the I / F circuit 107. Is done. Then, the roller of the pickup roller 7 is rotated by the forward rotation of the paper feed motor 102 to pick up several (ideally one) originals on the original table 2. The rotation direction is a direction in which the uppermost document is conveyed to the sheet feeding port.

  Here, when setting the duplex mode or the simplex mode, the same setting may be made for all documents set on the document table 2, or (first sheet, second sheet,... N). Different settings may be made for each of the originals (out of all 10 originals, the first and tenth sheets are in the duplex mode, the others are in the simplex mode, etc.).

  In the separation conveyance unit B, the paper feeding belt 9 is driven in the paper feeding direction by the normal rotation of the paper feeding motor 102, and the reverse roller 10 is driven to rotate in the reverse direction to the paper feeding by the normal rotation of 102, By separating the original below it, only the uppermost original can be fed. That is, the reverse roller 10 contacts the paper feed belt 9 with a predetermined pressure and operates as follows. When the reverse roller 10 is in direct contact with the paper feed belt 9 or is in contact with one original, the reverse roller 10 rotates counterclockwise as the paper feed belt 9 rotates. On the other hand, when two or more documents enter between the paper feeding belt 9 and the reverse roller 10, the turning force is set to be lower than the torque of the torque limiter. The reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess document, thereby preventing double feeding.

  The document separated into one sheet by the action of the sheet feeding belt 9 and the reverse roller 10 is sent to the positioning unit C by the sheet feeding belt 9, the leading edge is detected by the abutting sensor 11, and the pull-out roller further stops. It hits twelve. After that, the sheet feeding motor 102 is stopped in a state where it is sent by a predetermined distance by the detection of the abutting sensor 11 and is pressed against the pull-out roller 12 with a predetermined amount of deflection. As a result, the driving of the paper feed belt 9 is stopped. At this time, by rotating the pickup lifting / lowering motor 101, the pickup roller 7 is retracted from the upper surface of the document, and the document is sent only by the conveying force of the paper feed belt 9. As a result, the leading edge of the document enters the nip of the pair of upper and lower rollers of the pull-out roller 12, and the leading edge is aligned (skew correction).

  The pull-out roller 12 is a roller that has the skew correction function and transports the skew-corrected document after separation to the intermediate roller 14. The pull-out roller 12 is driven by the reverse rotation of the paper feed motor 102. At this time, that is, when the paper feed motor 102 is reverse, the pull-out roller 12 and the intermediate roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven.

  A plurality of document width sensors 13 are arranged in the depth direction, and detect the size in the width direction perpendicular to the transport direction of the document transported by the pull-out roller 12. The length of the document in the conveyance direction is detected from the motor pulse by reading the leading and trailing edges of the document with the butting sensor 11.

  When the document is conveyed from the positioning unit C to the turn unit D by driving the pull-out roller 12 and the intermediate roller 14, the conveyance speed at the positioning unit C is set to be higher than the conveyance speed at the first reading conveyance unit E. Thus, the processing time for sending the document to the reading unit is shortened.

  When the leading edge of the document is detected by the reading entrance sensor 15, before the leading edge of the document enters the nip between the pair of upper and lower rollers of the reading entrance roller 16, deceleration is started in order to make the document transportation speed the same as the scanning transportation speed. At the same time, the reading motor 103 is driven forward to drive the reading inlet roller 16, the reading outlet roller 23, and the CIS outlet roller 27. When the registration sensor 17 detects the leading edge of the document, the document sensor decelerates over a predetermined conveyance distance, temporarily stops before the first reading unit 20 in the first reading conveyance unit E, and sends an I / O to the main body control unit 111. A positioning stop signal is transmitted via the F circuit 107.

  Subsequently, when a reading start signal is received from the main body control unit 111, the document whose positioning has been stopped is transported at an increased speed so as to rise to a predetermined transport speed before the leading end of the document reaches the scanning position. At the timing when the leading edge of the document detected by the pulse count of the reading motor reaches the reading unit, a gate signal indicating an effective image area in the sub-scanning direction on the first surface is sent to the main body control unit 111 and the first reading unit 20 is scanned. Sent until the trailing edge is removed.

  In the case of single-sided document reading, the document that has passed through the first reading conveyance unit E is conveyed to the paper discharge unit G through the second reading unit 25. At this time, when the leading edge of the original is detected by the paper discharge sensor 24, the paper discharge motor 104 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise. The discharge motor drive speed is reduced immediately before the trailing edge of the document comes out of the nip between the upper and lower roller pairs of the discharge roller 28 by the discharge motor pulse count from the detection of the leading edge of the document by the discharge sensor 24. Control is performed so that the document discharged onto the tray 29 does not jump out.

  In the case of double-sided document reading, the second reading conveyance unit F detects the leading edge of the document by the paper discharge sensor 24 and then the second reading conveyance unit F at the timing when the leading edge of the document reaches the second reading unit 25. 2 A gate signal indicating an effective image area in the sub-scanning direction is transmitted from the controller unit 100 to the reading unit 25 until the trailing edge of the document passes through the reading unit. The second reading roller 26 serves as a reference white part for obtaining shading data in the second reading unit as well as suppressing the floating of the document in the second reading unit 25.

  FIG. 4 is a block diagram illustrating a main part of an electric circuit of a second reading unit of the sheet conveying apparatus. The second reading unit 25 has a light source unit 200 made of an LED array, a fluorescent lamp, a cold cathode tube, or the like. In addition, a plurality of sensor chips 201 arranged in the main scanning direction (direction corresponding to the document width direction), a plurality of OP amplifier circuits 202 individually connected to each sensor chip 201, and individually connected to each OP amplifier circuit 202 are connected. A plurality of A / D converters 203 are also provided. Further, it includes an image processing unit 204, a frame memory 205, an output control circuit 206, an I / F circuit 207, and the like.

  The sensor chip 201 includes a photoelectric conversion element called a 1 × contact image sensor and a condenser lens. A lighting ON signal is sent from the controller unit 100 to the light source unit 200 before a document (not shown) enters the reading position by the second reading unit 25. As a result, the light source unit 200 is turned on and irradiates the light toward the second surface of the document (not shown). The reflected light reflected from the second surface of the document is condensed on the photoelectric conversion element by the condensing lens and read as image information in the plurality of sensor chips 201.

  Image information read by each sensor chip 201 is amplified by an OP amplifier circuit 202 and then converted into digital image information by an A / D converter 203. The digital image information is input to the image processing unit 204 and subjected to shading correction and the like, and then temporarily stored in the frame memory 205. Thereafter, the data is converted into a data format acceptable by the main body control unit 111 by the output control circuit 206 and then output to the main body control unit 111 via the I / F circuit 107.

  It should be noted that a timing signal for notifying the timing at which the leading edge of the document reaches the reading position by the second reading unit 25 (image data after that timing is treated as valid data), a light source lighting signal, a power source, etc. Etc. are output.

  Hereinafter, the configuration of the sheet conveying apparatus according to the present embodiment will be described. First, the configuration of the paper feed cover unit 50 that is a cover unit will be described. 5A and 5B are cross-sectional views showing the open / close state of the sheet conveying apparatus. FIG. 5A shows the automatic document conveying apparatus 400 with the cover unit closed, and FIG. 5B shows the automatic document conveying apparatus with the cover unit opened. 400 is shown. The paper feed cover unit 50 is pivotable about the pivot point 401 at the lower left in the figure and can be opened. In the paper feed cover unit 50, a pull-out driven roller 52 having a metal shaft and a metal plate bracket 53 supporting the pull-out driven roller 52 are disposed. These need to be grounded and grounded.

  As shown in FIG. 5, in the automatic document feeder 400, when the paper feed cover unit 50 is changed from an open state (FIG. 5B) to a closed state (FIG. 5A), the apparatus utilizes magnetic force. The main body frame 54 of the main body is fixed. That is, a magnet catch 71 that is a magnetic attraction member is provided near M in the drawing of the automatic document feeder 400. When the paper feed cover unit 50 is closed, the magnet catch 71 is attracted to the main body frame 54 of the automatic document feeder 400, and the paper feed cover unit 50 is held in the closed state. Here, the main body frame 54 is, for example, steel, to which a magnet is attracted.

  The bracket 53 of the pull-out driven roller 52 is connected to the magnet catch 71 by a conducting wire 81, and the magnet catch 71 is electrically connected in a state of being attracted to the main body frame 54. Note that the metal member disposed in the paper feed cover unit 50 is electrically connected to the magnet catch 71 and grounded as necessary.

  Hereinafter, a magnet catch 71 used in the sheet conveying apparatus according to the present invention will be described.

<Embodiment 1>
FIGS. 6A to 6F are views showing a magnet catch according to the first embodiment of the sheet conveying apparatus, and FIG. 7 is a view showing an attached state of the magnet catch. The magnet catch 71 includes a magnet 72 that is a magnet member and two yoke members 73 and 73. As shown in FIG. 6A, a magnet 72 is arranged between the yoke members 73. The yoke members 73 and 73 are made of electromagnetic steel plates, and the magnet 72 is made of a ferrite self-magnet or the like. In this example, as shown in FIG. 6B, the yoke member 73 has holes 73a and 73a.

  On the other hand, as shown in FIGS. 6C and 6D, a box-shaped magnet catch mounting portion 55 is formed on the paper feed cover 51. As for this magnet catch attaching part 55, wall part 55a, 55b, 55c, 55d is standingly arranged by 4 directions. Further, the two opposing wall portions 55a and 55b are formed with projections 56 and 56 that fit into the hole portions 73a and 73a of the yoke members 73 and 73 when the magnet catch 71 is disposed. Further, the wall portion 55 c of the magnet catch mounting portion 55 is provided with a slit 57 for arranging the conducting member 60 on the upper side surface side of the magnet catch mounting portion 55.

  The conductive member 60 is formed by bending a metal leaf spring, which is an elastic member, and a ground wire 61 connected to the bracket 53 and the like is disposed. In order to arrange the magnet catch 71 in the magnet catch mounting portion 55, as shown in FIGS. 7A and 7B, the conducting member 60 is inserted from the slit 57 of the magnet catch mounting portion 55. Thereafter, the magnet catch 71 is inserted into the magnet catch mounting portion 55. Then, the projections 56 and 56 of the magnet catch mounting portion 55 are fitted in the holes 73 a and 73 a of the yoke members 73 and 73, and the magnet catch 71 is fixed in the magnet catch mounting portion 55 by the elastic force of the magnet catch mounting portion 55. The The conducting member 60 elastically contacts the yoke members 73 and 73, and the yoke members 73 and 73 and the metal member in the paper feed cover unit 50 to which the ground wire 61 is connected are electrically conductive. It becomes.

  In the first embodiment, when the paper feed cover unit 50 is in the closed state, as shown in FIGS. 7C and 7D, the magnet 72 is attached to the main body frame during sheet conveyance with the paper feed cover unit 50 in the closed state. 54 is brought into conduction. For this reason, the metal member in the paper feed cover unit 50 is grounded to the main body frame 54 via the ground wire 61, the conducting member 60, and the magnet catch 71. Further, the paper feed cover unit 50 is attracted to the main body frame 54 by a magnetic catch 71 by a magnetic force and does not rattle.

  In the present embodiment, since the magnet catch 71 is directly positioned and fixed with respect to the paper feed cover unit 50, the closed state of the paper feed cover unit 50 can be stabilized, and the contact between the magnet catch and the conducting member is possible. Can also be stabilized.

<Embodiment 2>
The magnet catch 71 according to the second embodiment is a magnet member made of a conductive material. In this example, as shown in FIGS. 6 (g) and 6 (h), a hole 72 a that fits into the protrusions 56 of the magnet catch mounting portion 55 is formed in the magnet 72. In the present embodiment, since the yoke is not necessary, the configuration can be simplified correspondingly. The paper feed cover 51 is made of resin, and the magnet catch can be attached as shown in FIG. 5.5 using the elasticity of the resin.

<Embodiment 3>
In Embodiment 3, the conducting member is made of a material that is attracted to the magnet. FIG. 8 is a view showing a magnet catch according to Embodiment 3 of the sheet conveying apparatus. As shown in FIGS. 8A and 8B, in this embodiment, the conducting member 62 is made of, for example, a steel plate. The conducting member 62 is connected to the ground wire 61. In the present embodiment, as shown in FIGS. 8C and 8D, after the conducting member 62 is inserted from the slit 57, the magnet catch 71 is attached to the magnet catch attachment portion 55. Thereby, the conducting member 62 is attracted to the yoke members 73 and 73 of the magnet catch 71 by a magnetic force, and the conducting member 62 and the magnet catch 71 are more surely connected to each other.

<Embodiment 4>
In the fourth embodiment, the magnet catch is disposed on the magnet catch mounting portion by fastening the screw member, and the ground wire is attached to the magnet catch with the same screw member. FIG. 9 is a view showing a magnet catch according to Embodiment 4 of the sheet conveying apparatus, and FIG. 10 is a view showing an attached state of the magnet catch.

  In the fourth embodiment, as shown in FIG. 10, the magnet catch 71 </ b> A is fixed to the paper feed cover 51 using a screw member 70. At this time, the ground wire 61 is provided with a washer 61 a, and this washer 61 a can be connected to the magnet catch 71 by the screw member 70. For this reason, among the wall portions 58a, 58b, 58c and 58d constituting the magnet catch attachment portion 58, a screw insertion hole 59a is formed in the wall portion 58a, and a screw attachment hole 59 in which a female screw is formed in the wall portion 58b. The magnet 72 and the yoke member 73 constituting the magnet catch 71A are formed with a hole 72a through which the screw member passes and holes 73a and 73a. In the present embodiment, since the conductive member is not used, the configuration can be further simplified.

20: First reading unit 25: Second reading unit 50: Paper feed cover unit (cover unit)
51: Paper feed cover 54: Main body frame 55: Magnet catch mounting portion 55a, 55b: Wall portion 56, 56: Projection 60: Conducting member 61: Ground wire 71: Magnet catch (magnetic force adsorbing member)
72: Magnet (Magnet member)
73, 73: Yoke members 73a, 73a: Hole 300: Image forming apparatus 350: Image reading unit (image reading apparatus)
400: Automatic document feeder (sheet feeder)

JP-A-6-325806

Claims (7)

Body frame,
A cover unit that is movable and openable with respect to the main body frame;
Provided in the cover unit, and the magnetic attraction member that holds with a magnet member and the yoke member, the closed state of the cover unit adsorbed magnetically to the body frame,
A conductive member that contacts the yoke member and is electrically connected to a metal member disposed in the cover unit;
In the sheet conveying apparatus that makes the metal member in the cover unit conductive with the main body frame when the cover unit is in a closed state,
Protrusion on one of the cover unit and the yoke member, a hole in the other, and the yoke member fixed directly to the cover unit by fitting the protrusion into the hole;
A sheet conveying apparatus characterized by the above.   The sheet conveying apparatus according to claim 1, wherein the conducting member that contacts the yoke member is an elastic member.   The sheet conveying apparatus according to claim 1, wherein the conductive member is formed of a material that is attracted to the magnet member. Body frame,
A cover unit that is movable and openable with respect to the main body frame;
A magnetic force adsorbing member comprising a magnet member provided in the cover unit and adhering to the main body frame by a magnetic force to hold the cover unit in a closed state;
A contact member that contacts the magnet member and is electrically connected to the metal member disposed in the cover unit;
In the sheet conveying apparatus that makes the metal member in the cover unit conductive with the main body frame when the cover unit is in a closed state,
The sheet conveying apparatus, wherein the cover unit is provided with a protrusion, the magnet member is provided with a hole, and the protrusion is fitted into the hole so that the magnet member is directly fixed to the cover unit . An image reading apparatus comprising: the sheet conveying apparatus according to claim 1; and an image reading unit that reads an image of a sheet conveyed by the sheet conveying apparatus. An image forming apparatus comprising the sheet conveying device according to claim 1. An image forming apparatus comprising the image reading apparatus according to claim 5 .