JP2011195240A - Carrying unit and image forming device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrying unit constructed to suppress the deformation of a resin-molded guide face and the accumulation of static electricity, and to provide an image forming device equipped therewith.SOLUTION: The carrying unit includes a frame body including a first face in which an introduction port is formed to introduce sheets, and a second face on the opposite side to the first face, in which a discharge port is formed to discharge the sheets, a guide part having the resin guide face for guiding the sheets from the introduction port toward the discharge port, and a reinforcing face on the opposite side to the guide face, a reinforcing plate connected to the reinforcing face and extending in the cross direction of the sheets, and a conducting structure for conducting static electricity in the frame body.

Description

  The present invention relates to a conveyance unit for conveying a sheet and an image forming apparatus including the conveyance unit.

  An image forming apparatus such as a copier, a printer, a facsimile machine, or a multifunction machine having these functions generally forms a toner image while conveying a sheet in a housing. In many cases, the sheet is guided by a guide member (for example, Patent Document 1).

  Ribs for reducing the frictional force with the sheet may be formed on the guide surface of the guide member for guiding the sheet. For this reason, the guide member often has a relatively complicated shape, and is generally manufactured by resin molding.

JP 2004-352380 A

  A guide surface molded from a resin has a relatively low mechanical strength. For this reason, it may be deformed by external force, heat, or deterioration with time. The deformed guide surface cannot properly guide the sheet, and as a result, a conveyance failure or a defect in a predetermined process executed in a downstream process occurs.

  Another drawback of the guide surface molded from resin is that static electricity due to friction with the sheet is likely to accumulate. Accumulation of static electricity causes, for example, poor conveyance and malfunction of the image forming apparatus.

  The conveyance unit of Patent Document 1 has a guide surface for guiding a sheet being conveyed. A plurality of ribs along the sheet conveyance direction are formed on the guide surface, but these ribs cannot sufficiently supplement the mechanical strength of the guide surface. For example, these ribs hardly contribute to the rigidity against the bending of the guide surface in the direction away from the sheet or in the direction close to the sheet.

  The transport unit of Patent Document 1 is used by stacking transport devices. Static electricity generated by rubbing between the guide surface of the lower transport device and the sheet is accumulated in the frame of the transport device, causing the sheet being transported to stick to the guide surface and causing a transport failure. Or, the accumulated static electricity discharge causes the device to malfunction.

  The present invention has been made to solve the above-described problem, and includes a transport unit having a structure for suppressing deformation of a guide surface molded from a resin and accumulation of static electricity, and an image forming apparatus including the transport unit. The purpose is to provide.

  A conveyance unit according to one aspect of the present invention includes a first conveyance device and a second conveyance device that are formed to convey sheets and are stacked on each other, and the first conveyance device and the second conveyance device include: A frame including a first surface formed with an introduction port through which a sheet is introduced, and a second surface formed with a discharge port through which the sheet is discharged and opposite to the first surface; A guide portion having a resin guide surface that guides the sheet from the introduction port to the discharge port, and a reinforcing surface opposite to the guide surface, and a width direction of the sheet connected to the reinforcing surface And a conductive structure for conducting static electricity in the frame body, wherein the reinforcing plate includes a first conductive portion exposed on the first surface, and the conductive structure includes the second conductive structure. A second conductive part exposed on the surface, and the first conductive part A third conductive portion connecting to the second conductive portion, wherein the second transport device is adjacent to the second surface of the first transport device and the first surface of the second transport device. The discharge port of the first transfer device and the introduction port of the second transfer device communicate with each other, and the second conductive portion of the first transfer device is connected to the second transfer device of the second transfer device. It is electrically connected to one conductive part (claim 1).

  According to the said structure, a sheet | seat is conveyed from the inlet formed in the 1st surface of a frame to the discharge port formed in the 2nd surface on the opposite side to a 1st surface. The sheet heading from the introduction port to the discharge port is guided by a guide unit having a resin guide surface. A reinforcing plate extending in the width direction of the sheet is connected to the reinforcing surface on the opposite side of the guide surface. Thus, deformation of the guide surface is suppressed. In addition, the second device is disposed so that the second surface of the second transport device is adjacent to the first surface of the first transport device. Since the discharge port of the first conveying device communicates with the inlet of the second conveying device, the sheet is suitably conveyed from the first conveying device to the second conveying device. In addition, static electricity in the frame of the first transport device is transmitted to the first conductive portion of the second transport device through the second conductive portion of the first transport device. Thus, a conductive path is established between the first transfer device and the second transfer device, and accumulation of static electricity within the frame is preferably avoided.

  In the above configuration, the apparatus further includes a conveyance roller that conveys the sheet guided by the guide surface toward the discharge port, and a conductive shaft that supports the conveyance roller, and the conductive structure includes the shaft and the shaft. It is preferable to include a fourth conductive portion that electrically connects the second conductive portion.

  According to the above configuration, the static electricity generated on the guide surface or the transport roller is sent to the conductive path established between the first transport device and the second transport device through the conductive shaft.

  An image forming apparatus according to another aspect of the present invention is formed to form an image on a sheet, a housing that houses the image forming unit, and a sheet that is conveyed into the housing. A first transport device and a second transport device stacked on top of each other, the second transport device being disposed between the housing and the first transport device, the first transport device and the second transport device The second conveying device includes a first surface on which an introduction port for introducing a sheet is formed, and a second surface on which the discharge port for discharging the sheet is formed and opposite to the first surface. A guide part having a frame, a resin guide surface for guiding the sheet from the introduction port to the discharge port, and a reinforcement surface opposite to the guide surface, and connected to the reinforcement surface A reinforcing plate extending in the width direction of the sheet and the static electricity in the frame body. The reinforcing plate includes a first conductive portion exposed on the first surface, and the conductive structure includes a second conductive portion exposed on the second surface, and the first conductive portion. A third conductive part connecting the conductive part and the second conductive part, wherein the second transport device is disposed on the second surface of the first transport device and the first surface of the second transport device. Are arranged adjacent to each other, and the discharge port of the first transfer device and the introduction port of the second transfer device communicate with each other, and the second conductive portion of the first transfer device is connected to the second transfer device. The casing is electrically connected to the first conductive portion of the apparatus, and the casing is electrically connected to the fifth conductive portion, and the fifth conductive portion is electrically connected to the second conductive portion of the second transport device. And a ground wire connected to the terminal (claim 3).

  According to the above configuration, the first transport device and the second transport device transport the sheet in the housing that houses the image forming unit that forms an image on the sheet. The sheet is conveyed from the introduction port formed on the first surface of the frame to the discharge port formed on the second surface opposite to the first surface. The sheet heading from the introduction port to the discharge port is guided by a guide unit having a resin guide surface. A reinforcing plate extending in the width direction of the sheet is connected to the reinforcing surface on the opposite side of the guide surface. Thus, deformation of the guide surface is suppressed. The second conveying device is disposed between the housing of the image forming apparatus and the first conveying device. Since the discharge port of the first conveyance device communicates with the introduction port of the second conveyance device, the sheet is suitably conveyed from the first conveyance device to the second conveyance device. Further, the sheet is conveyed into the housing through the second conveying device. Therefore, the sheet is suitably conveyed between the first conveying apparatus, the second conveying apparatus, and the image forming apparatus. In addition, static electricity in the frame of the first transport device is transmitted to the first conductive portion of the second transport device through the second conductive portion of the first transport device. The static electricity transmitted to the second transport device is transmitted to the second conductive portion through the third conductive portion. The second conductive part is electrically connected to the fifth conductive part of the housing. The fifth conductive portion is electrically connected to the ground wire. Thus, accumulation of static electricity is preferably avoided.

  As described above, the present invention can suitably suppress the deformation of the guide surface molded from resin and the accumulation of static electricity.

1 is a diagram schematically showing an internal structure of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a transport unit of the image forming apparatus illustrated in FIG. 1. It is a perspective view which shows the conveyance unit from which the top plate was removed. It is a perspective view which shows the guide part of the conveyance unit shown by FIG. It is a schematic diagram which shows the electroconductive structure of the conveyance unit shown by FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that terms used in the following description, such as “up”, “down”, “left”, “right” and the like, are merely for the purpose of clarifying the explanation and do not limit the present invention. Not what you want. In the following description, the term “sheet” means copy paper, coated paper, OHP sheet, cardboard, postcard, tracing paper, and other sheet materials that are subjected to image forming processing. The term “sheet leading edge” means the edge of the sheet positioned at the leading edge in the sheet conveyance direction. The terms “upstream”, “downstream” and similar terms used in the following description mean “upstream”, “downstream” and similar concepts in the sheet conveyance direction.

  FIG. 1 schematically shows the internal structure of the image forming apparatus. The image forming apparatus shown in FIG. 1 is a printer. However, in another embodiment, an arbitrary apparatus for forming an image such as a copier, a facsimile machine, or a multifunction machine having these functions is used as the image forming apparatus. May be.

  The image forming apparatus 1 is disposed under various apparatuses (for example, an image forming unit 410 described later) for forming an image on a sheet, a housing 2 that houses these devices, and a lower portion of the housing 2. A transfer device 600. In the present embodiment, two transport devices 600 are disposed below the housing 2, but three or more transport devices 600 may be disposed below the housing 2. In the present embodiment, the lowermost transport device 600 is referred to as a first transport device 610 for convenience, and is transported between the housing 2 and the first transport device 610. The apparatus 600 is referred to as a second transport apparatus 620. Therefore, in this embodiment, the 1st conveying apparatus 610 and the 2nd conveying apparatus 620 which were mutually stacked | stacked comprise a conveyance unit.

  The image forming apparatus 1 receives a control signal related to the image forming process from an external device (for example, a personal computer (not shown)), and performs various operations necessary for the image forming process based on the control signal. The image forming apparatus 1 includes a first cassette 631 that is removably accommodated in the first transport device 610, a second cassette 632 that is removably accommodated in the second transport device 620, and a lower portion of the housing 2. It includes a third cassette 633 that is removably accommodated. For example, when the sheets accommodated in the first cassette 631, the second cassette 632, and the third cassette 633 have different dimensions, the image forming apparatus 1 determines whether the sheets are specified by the control signal. Cassettes 631, 632, and 633 serving as sheet supply sources are selected. The image forming apparatus 1 further includes a tray 510. The tray 510 can be rotated up and down with respect to the housing 2. The user may rotate the tray 510 downward and place the sheet on the tray 510. If the control signal from the external device designates the tray 510 as a sheet supply source, the sheet on the tray 510 is pulled into the housing 2.

  An inlet 641 for introducing a sheet is formed on the lower surface of the conveying device 600. Further, a discharge port 642 through which the sheet is discharged is formed on the upper surface of the conveying device 600. In the present embodiment, the lower surface of the transfer device 600 is referred to as a first surface 643 for convenience. Further, the upper surface (that is, the surface opposite to the first surface 643) of the transfer device 600 is referred to as a second surface 644 for convenience. A connection conveyance path 645 extending between the introduction port 641 and the discharge port 642 is formed in the conveyance device 600. The first surface 643 of the second transport device 620 is adjacent to the second surface 644 of the first transport device 610. Further, the discharge port 642 of the first transport device 610 communicates with the introduction port 641 of the second transport device 620. Thus, the connection conveyance path 645 formed in the first conveyance apparatus 610 and the connection conveyance path 645 formed in the second conveyance apparatus 620 are continuously connected.

  Each of the cassettes 631, 632, 633 includes a lift plate 634 for pushing up the leading edge of the sheets stored in the cassettes 631, 632, 633. The conveyance device 600 includes a pickup roller 646 disposed above the downstream end (the right end in FIG. 1) of the lift plate 634. The pickup roller 646 contacts the leading edge of the sheet pushed up by the lift plate 634. By the rotation of the pickup roller 646, the sheet is taken out from the cassettes 631 and 632 and conveyed downstream.

  The conveyance device 600 includes a paper feed roller 647 and a retard roller 648 disposed to face the paper feed roller 647. The pickup roller 646 feeds the sheet between the paper feed roller 647 and the retard roller 648. The paper feed roller 647 rotates to send the sheet further downstream. The rotation of the retard roller 648 is controlled by a torque limiter (not shown). When the pickup roller 646 feeds two or more sheets between the paper feed roller 647 and the retard roller 648, the torque limiter is activated, and the retard roller 648 is made non-rotatable. As a result, the retard roller 648 provides a frictional force that resists the conveyance of a sheet other than the uppermost sheet (a sheet that is in direct contact with the sheet feeding roller 647). When the pickup roller 646 feeds one sheet between the sheet feeding roller 647 and the retard roller 648, the torque limiter does not operate, and the retard roller 648 rotates according to the conveyance of the sheet. As a result, the sheets are sent downstream one by one.

  The conveyance device 600 includes a conveyance roller pair 649 attached to the discharge port 642. The pair of conveyance rollers 649 of the first conveyance device 610 sends the sheet fed by the paper feed roller 647 of the first conveyance device 610 to the introduction port 641 of the second conveyance device 620 through the discharge port 642. The conveyance roller pair 649 of the second conveyance device 620 is configured so that the sheet fed by the paper feed roller 647 of the second conveyance device 620 or the sheet fed by the conveyance roller pair 649 of the first conveyance device 610 is outside the second conveyance device 620. To discharge.

  An introduction port 650 is formed on the lower surface of the housing 2. In addition, an introduction conveyance path 651 extending upward from the introduction port 650 as a base end is formed inside the housing 2. The sheet fed by the pair of conveyance rollers 649 of the second conveyance device 620 is introduced into the introduction conveyance path 651 through the introduction port 650 of the housing 2. Thus, the conveyance device 600 can suitably convey the sheet into the housing 2.

  The image forming apparatus 1 includes a pickup roller 311 disposed above the downstream end (right end in FIG. 1) of the lift plate 634 of the third cassette 633. The pickup roller 311 comes into contact with the leading edge of the sheet pushed up by the lift plate 634. By the rotation of the pickup roller 311, the sheet is taken out from the third cassette 633 and conveyed downstream.

  The image forming apparatus 1 includes a paper feed roller 312 and a retard roller 313 disposed to face the paper feed roller 312. The pickup roller 311 sends the sheet between the paper feed roller 312 and the retard roller 313. The paper feed roller 312 rotates to send the sheet further downstream. The rotation of the retard roller 313 is controlled by a torque limiter (not shown). When the pickup roller 311 feeds two or more sheets between the paper feed roller 312 and the retard roller 313, the torque limiter is activated to make the retard roller 313 non-rotatable. As a result, the retard roller 313 gives a frictional force that resists the conveyance of a sheet other than the uppermost sheet (a sheet that is in direct contact with the paper feed roller 312). When the pickup roller 311 feeds one sheet between the paper feed roller 312 and the retard roller 313, the torque limiter does not operate and the retard roller 313 rotates according to the conveyance of the sheet. Therefore, as a result, the sheets are sent downstream one by one.

  The image forming apparatus 1 includes a registration roller pair 320. The registration roller pair 320 sends the sheet to the image forming unit 410 in synchronization with the image forming process executed by the image forming unit 410. In the housing 2, a first paper feed conveyance path 310 that guides the sheet fed by the paper feed roller 312 to the registration roller pair 320 is formed. Between the registration roller pair 320 and the paper feed roller 312, a transport roller pair 315 for transporting a sheet passing through the first paper feed transport path 310 is disposed. The sheet introduced into the introduction conveyance path 651 or the sheet sent out from the third cassette 633 is conveyed to the registration roller pair 320 by the conveyance roller pair 315.

  The image forming apparatus 1 includes a sheet feeding structure 520 that pulls a sheet on the tray 510 into the housing 2. The sheet feeding structure 520 is disposed so as to be able to come into contact with the lift plate 521 that pushes up the leading edge of the sheet on the tray 510 that is inclined downward toward the housing 2, and the leading edge of the sheet pushed up by the lift plate 521. A sheet feeding roller 522 and a separation pad 523 disposed below the sheet feeding roller 522. When the sheet feed roller 522 rotates, the sheet passes between the sheet feed roller 522 and the separation pad 523. The separation pad 523 gives a frictional force to the sheet passing between the paper feed roller 522 and the separation pad 523. Therefore, when the paper feed roller 522 tries to draw a plurality of sheets into the housing 2, the separation pad 523 is transported to a sheet other than the uppermost sheet (a sheet that directly contacts the paper feed roller 522). A frictional force acting in the opposite direction is applied to prevent the frictional force from being pulled into the housing 2. As a result, the sheets are fed into the housing 2 one by one.

  A second paper feed conveyance path 530 for guiding sheets from the tray 510 is formed in the housing 2. The second paper feed conveyance path 530 extends toward the back wall 24 of the housing 2 above the third cassette 633, and then gradually curves upward and toward the registration roller pair 320. The second paper feed path 530 joins the first paper feed path 310 upstream of the registration roller pair 320. Three conveyance roller pairs 360 are arranged in a substantially straight section of the second paper feed conveyance path 530 before bending upward. The transport roller pair 360 transports the sheet in the second paper feed transport path 530 toward the registration roller pair 320.

  In the housing 2, there are a section from the registration roller pair 320 to the fixing unit 430, a main conveyance path 330 that guides the sheet, a section from the fixing unit 430 to the discharge unit 450, and a discharge conveyance path 340 that guides the sheet. It is formed. The sheet that has reached the registration roller pair 320 is subjected to an image forming process by the image forming unit 410 and a toner image fixing process by the fixing unit 430 while passing through the main conveyance path 330 and the discharge conveyance path 340. Thereafter, if the user causes the image forming apparatus 1 to perform single-sided printing, the sheet is discharged onto the discharge tray 23 that forms a part of the upper surface of the housing 2 through the discharge portion 450 provided in the discharge conveyance path 340. Is done. The discharged sheets are stacked on the paper discharge tray 23.

  When the user causes the image forming apparatus 1 to perform double-sided printing, the discharge unit 450 sends the sheet sent from the fixing unit 430 to the discharge conveyance path 340 out of the case 2 by a predetermined amount, and then enters the case 2. Perform a switchback operation to pull back. The conveyance path further includes a return conveyance path 350 for guiding the sheet pulled back by the discharge unit 450. The return conveyance path 350 extends from the discharge portion 450 toward the back wall 24 of the housing 2 and then extends downward. Thereafter, the return transport path 350 extends toward the first paper feed transport path 310 and joins the first paper feed transport path 310 upstream of the transport roller pair 360. At appropriate positions on the return conveyance path 350, a conveyance roller pair 360 for conveying the sheet guided by these conveyance paths is disposed.

  The image forming unit 410 includes a yellow toner container 900Y, a magenta toner container 900M, a cyan toner container 900C, and a black toner container 900K. Below these containers, developing devices 10Y, 10M, 10C, and 10K corresponding to the respective colors of YMCK are disposed. The image forming unit 410 forms an image on a sheet using toner stored in the toner containers 900Y, 900M, 900C, and 900K.

  The image forming unit 410 includes a photoconductor drum 17 (a photoconductor on which a latent image is formed by an electrophotographic method) that carries a toner image of each color. As the photosensitive drum 17, a photosensitive drum using an amorphous silicon (a-Si) material can be used. The photosensitive drums 17 are supplied with yellow, magenta, cyan, and black toners from the toner containers 900Y, 900M, 900C, and 900K, respectively.

  Around the photosensitive drum 17, a charger 16, a developing device 10 (10Y, 10M, 10C, 10K), a transfer device (transfer roller) 19 and a cleaning device 18 are arranged. The charger 16 uniformly charges the surface of the photosensitive drum 17. The surface of the photosensitive drum 17 after charging is exposed by the exposure unit 94 to form an electrostatic latent image. For example, the exposure unit 94 irradiates a laser beam based on an image signal (a signal including image information) from an external device. The developing devices 10Y, 10M, 10C, and 10K develop the electrostatic latent images formed on the respective photosensitive drums 17 using the toners of the respective colors supplied from the toner containers 900Y, 900M, 900C, and 900K, respectively ( Visualization). The transfer roller 19 forms a nip portion with the photosensitive drum 17 across the intermediate transfer belt 921, and primarily transfers the toner image on the photosensitive drum 17 onto the intermediate transfer belt 921. The cleaning device 18 cleans the peripheral surface of the photosensitive drum 17 after the toner image is transferred.

  Each developing device 10Y, 10M, 10C, 10K includes a developing case 20. A two-component developer having a magnetic carrier and toner is accommodated in the developing case 20. Further, in the developing case 20, two stirring rollers 11 and 12 (developer stirring members) are rotatably arranged in parallel near the bottom of the developing case 20 with the longitudinal direction as an axial direction.

  A developer circulation path is set on the inner bottom surface of the developing case 20, and the stirring rollers 11 and 12 are disposed in the circulation path. A partition wall 201 erected from the bottom of the developing case 20 is provided in the axial direction between the stirring rollers 11 and 12. The partition wall 201 divides the circulation path. A circulation path is formed so as to circulate around the partition wall 201. The two-component developer is charged while being stirred and conveyed on the circulation path by the stirring rollers 11 and 12.

  The two-component developer circulates in the developing case 20 while being stirred by the stirring rollers 11 and 12, and the toner is charged. The two-component developer on the stirring roller 11 is attracted and conveyed by the magnetic roller 14 located on the upper side. The sucked two-component developer forms a magnetic brush (not shown) on the magnetic roller 14. The layer thickness of the magnetic brush is regulated by the doctor blade 13. The toner layer on the developing roller 15 is formed by a potential difference between the magnetic roller 14 and the developing roller 15. The electrostatic latent image on the photosensitive drum 17 is developed by the toner layer.

  The exposure unit 94 includes various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror. Light based on an image signal is provided on the peripheral surface of the photosensitive drum 17 provided in each of the image forming units 410. To form an electrostatic latent image.

  The intermediate transfer unit 92 includes an intermediate transfer belt 921, a driving roller 922, and a driven roller 923. On the intermediate transfer belt 921, toner images are overcoated from a plurality of photosensitive drums 17 (primary transfer). The overcoated toner image is secondarily transferred to a sheet supplied from the cassettes 631, 632, 633 or the tray 510 by the secondary transfer unit 98. A driving roller 922 and a driven roller 923 that rotate the intermediate transfer belt 921 are rotatably supported by the housing 2.

  The sheet fed from the registration roller pair 320 is supplied between the intermediate transfer belt 921 and the transfer roller 981 constituting the secondary transfer unit 98. Thereafter, the sheet is sent to the fixing unit 430 while carrying the toner image transferred by the secondary transfer unit 98.

  The fixing unit 430 includes a heating roller 432 including a heater 431 and a pressure roller 433 pressed against the heating roller 432. The sheet sent out from the secondary transfer unit 98 is sent between the heating roller 432 and the pressure roller 433. The toner on the sheet is melted by receiving heat energy from the heating roller 432 and is fixed to the sheet by receiving pressure from the pressure roller 433. After fixing the toner on the sheet, the fixing unit 430 sends the sheet to the discharge unit 450 via the discharge conveyance path 340.

  The discharge unit 450 includes a discharge roller pair 451. The discharge roller pair 451 is formed so as to be capable of normal rotation and reverse rotation. Thereby, the above-described switchback operation is achieved.

  FIG. 2 shows the transfer device 600. FIG. 2A is a plan view of the transfer device 600. FIG. 2B is a perspective view of the transfer device 600. The conveyance apparatus 600 will be described with reference to FIG. 1 in conjunction with FIG. 2.

  The conveyance device 600 includes a frame body 660 having a substantially rectangular tube shape. The frame 660 includes a third surface 661 that is continuous with the front wall 25 of the housing 2 of the image forming apparatus 1, a fourth surface 662 that is continuous with the back wall 24 of the housing 2 of the image forming apparatus 1, a third surface 661, and A pair of side walls 663 extending between both ends of each of the fourth surfaces 662. The third surfaces 661 of the first transfer device 610 and the second transfer device 620 are used to insert the first cassette 631 and the second cassette 632, respectively.

  The conveyance device 600 includes a first cover 670 for removing a sheet jammed in the connection conveyance path 645 formed in the frame 660. The first cover 670 is rotatably connected to the fourth surface 662 of the frame body 660. A handle portion 671 is formed on the outer surface of the first cover 670 and is recessed so that the user's finger can be inserted. The user can insert a finger into the handle portion 671 and rotate the first cover 670 up and down around the lower edge of the first cover 670.

  The conveyance device 600 includes a first top plate 681, a second top plate 682, a third top plate 683, and a fourth top plate 684 that partially close an opening formed on the upper surface of the frame body 660. The first top plate 681, the second top plate 682, the third top plate 683, and the fourth top plate 684 form the second surface 644 of the transfer device 600 described with reference to FIG. The first top plate 681 extends between the upper edges of each of the pair of side walls 663, and the edge of the first top plate 681 forms a discharge port 642. On the lower surface of the first top plate 681, the pickup roller 646, the paper feed roller 647, the driving roller 732 forming the conveying roller pair 649, and the driving device for driving them (not shown) are described. Connected). A second conductive portion 692 of a conductive structure 690 described later is attached to the upper surface of the first top plate 681. Thus, the second conductive portion 692 is exposed on the second surface 644 of the transfer device 600. The second conductive portion 692 is an elongated plate made of a conductive material, and extends between the pair of side walls 663 on the upper surface of the first top plate 681.

  The second top plate 682 is disposed between the first top plate 681 and the upper edge of the third surface 661. The lower surface of the second top plate 682 of each of the first transport device 610 and the second transport device 620 includes a fan 685 for sending air current into the first cassette 631 and the second cassette 632. The airflow from the fan 685 reduces the suction force between the sheets in the first cassette 631 and the second cassette 632 and suppresses the double feeding of the sheets. Each of the third top plate 683 and the fourth top plate 684 is disposed so as to close a region surrounded by the upper edges of the first top plate, the second top plate 682, and the pair of side walls 663.

  FIG. 3 is a perspective view of the transfer device 600 with the first top plate 681 and the second top plate 682 removed. 3A and 3B are drawn from different angles. The conveyance device 600 will be further described with reference to FIGS. 1 and 2 in conjunction with FIG. 3.

  Openings 664 into which the first cassette 631 and the second cassette 632 are inserted are formed in the third surfaces 661 of the first transport device 610 and the second transport device 620, respectively. In addition, a space for accommodating the first cassette 631 and the second cassette 632 is formed in the frame 660 of the first transport device 610 and the second transport device 620. The user can insert the first cassette 631 and the second cassette 632 into the first transport device 610 and the second transport device 620 through the opening 664, respectively.

  A fan 686 is attached to the inner surface of the side wall 663. The fan 686 sends airflow into the first cassette 631 and the second cassette 632 in the same manner as the fan 685 attached to the second top plate 682 described with reference to FIG. The airflow from the fan 686 reduces the suction force between the sheets in the first cassette 631 and the second cassette 632, and suppresses the double feeding of the sheets.

  The transfer device 600 includes a guide unit 700 disposed in the frame 660. The guide part 700 extends between the inner surfaces of the pair of side walls 663. The guide unit 700 includes a first guide plate 710 that forms a first guide surface 711 that forms a connection conveyance path 645. The first guide surface 711 guides the sheet from the introduction port 641 toward the discharge port 642 as described with reference to FIG. The guide portions 700 of the first transport device 610 and the second transport device 620 further form a second guide surface 721 for guiding the sheet taken out from the first cassette 631 and the second cassette 632 by the pickup roller 646. A guide plate 720 is included. The second guide plate 720 of each of the first conveyance device 610 and the second conveyance device 620 guides the sheet fed from the first cassette 631 and the second cassette 632 toward the discharge port 642. Since the first guide plate 710 and the second guide plate 720 include ribs extending along the sheet conveyance direction and have a relatively complicated shape, the first guide plate 710 and the second guide plate 720 are preferably molded from resin.

  A second cover 730 is disposed between the first cover 670 and the first guide plate 710. Similar to the guide portion 700, the second cover 730 extends between the inner surfaces of the pair of side walls 663. The second cover 730 rotates up and down in conjunction with the first cover 670. Therefore, when the user inserts a finger into the handle portion 671 of the first cover 670 and rotates the first cover 670, the second cover 730 also rotates about the lower edge of the second cover 730. . Thus, the first guide surface 711 is exposed to the outside, and the sheet jammed in the connection conveyance path 645 is suitably removed.

  The introduction port 641 described with reference to FIG. 1 is formed between the lower edge of the second cover 730 and the lower edge of the guide portion 700. The discharge port 642 described with reference to FIGS. 1 and 2 is formed between the upper edge of the second cover 730 and the upper edge of the guide portion 700.

  The conveyance device 600 includes a shaft 731 supported on the upper portion of the second cover 730 and a pair of driven rollers 733 supported on the shaft 731. The driven roller 733 is pressed against the driving roller 732 of the conveying roller pair 649 and rotates together with the driving roller 732. Therefore, the driving roller 732 and the driven roller 733 are used as a conveyance roller that conveys the sheet guided by the first guide surface 711 toward the discharge port 642. The shaft 731 is formed of a conductive material, and transmits static electricity generated on the transport roller 732 and the first guide surface 711 to a conductive structure 690 described later.

  The conveying device 600 includes a reinforcing plate 740 extending in the sheet width direction between the pair of side walls 663. The cross section of the reinforcing plate 740 is substantially L-shaped. The reinforcing plate 740 includes a connection portion 741 connected to the guide portion 700 and a first conductive portion 742 exposed on the lower surface of the frame body 660 (that is, the first surface 643 of the transfer device 600). The reinforcing plate 740 is preferably formed from a conductive metal material in order to achieve both an increase in mechanical strength of the guide portion 700 and a conductive function.

  The first conductive portion 742 of the second transfer device 620 contacts the second conductive portion 692 of the first transfer device 610. Thus, electrical connection between the first conductive unit 742 and the second conductive unit 692 is established, and conduction from the first transfer device 610 to the second transfer device 620 is achieved.

  FIG. 4 is a perspective view of the guide unit 700. 4A and 4B are drawn from different angles. The guide unit 700 will be described with reference to FIG. 1 in conjunction with FIG. 4.

  As described above, the guide unit 700 includes the first guide plate 710 and the second guide plate 720. As described above, the first guide plate 710 includes the first guide surface 711 that forms the connection conveyance path 645 and the reinforcing surface 712 opposite to the first guide surface 711. A connecting portion 741 of the reinforcing plate 740 is connected to the reinforcing surface 712. Thus, deformation of the first guide plate 710 is suppressed. The first guide plate 710 includes a plurality of ribs 713 protruding from the first guide surface 711. The rib 713 extends along the sheet conveyance direction in the connection conveyance path 645.

  The lower surface of the second guide plate 720 is connected to the rib 713. The second guide plate 720 is gently curved upward. The retard roller 648 described with reference to FIG. 1 and the torque limiter 481 for controlling the rotation of the retard roller 648 are embedded in a recess formed in the center of the second guide plate 720.

  FIG. 5 is a schematic diagram of the conductive structure 690. The conductive structure 690 will be described with reference to FIGS. 1 to 3 in conjunction with FIG.

  In addition to the second conductive portion 692 described with reference to FIG. 2, the conductive structure 690 includes a third conductive portion 743 that electrically connects the second conductive portion 692 and the first conductive portion 742 of the reinforcing plate 740. And a fourth conductive portion 744 that electrically connects the shaft 731 and the second conductive portion 692. Static electricity generated by friction between the first guide plate 710 and / or the driven roller 733 of the first transport device 610 and the sheet is sent to the second conductive portion 692 through the shaft 731 and the fourth conductive portion 744. As described with reference to FIG. 3, the second conductive portion 692 of the first transport device 610 and the first conductive portion 742 of the second transport device 620 are electrically connected, and thus the first transport device 610. The second transfer device 620 is preferably electrically conductive. Electricity that has reached the first conductive portion 742 of the second transport device 620 is transmitted to the second conductive portion 692 through the third conductive portion 743. In another embodiment, the fourth conductive portion may be connected to a conductive shaft that supports the driving roller 732 that transmits the driving force to the driven roller 733 instead of or in addition to the shaft 731. Good.

  A fifth conductive portion 745 is attached to the lower surface of the housing 2 of the image forming apparatus 1. The fifth conductive unit 745 is in contact with the second conductive unit 692 of the second transport device 620. Thus, the electricity reaching the second conductive portion 692 of the second transport device 620 reaches the fifth conductive portion 745 attached to the housing 2. The fifth conductive portion 745 is electrically connected to the ground wire 746. The ground wire 746 is properly grounded.

  As shown in FIG. 5, the fourth conductive portion 744 may be formed of a metal coil spring, for example. One end of the fourth conductive portion 744 is connected to the shaft 731 via a metal bracket 737 that slidably contacts the rotating shaft 731. The other end of the fourth conductive portion 744 is engaged with a hole 738 formed in the second conductive portion 692. The fourth conductive portion 744 extends between the second conductive portion 692 and the shaft 731. Thus, during the rotation of the shaft 731, the fourth conductive portion 744 stably maintains the electrical connection between the shaft 731 and the second conductive portion 692.

  A metal wire 739 bent into a mountain shape is connected to the upper end portion of the third conductive portion 743 connected to the second conductive portion 692. The third conductive portion 743 is formed of, for example, a metal coil spring, similarly to the fourth conductive portion 744. Thus, the third conductive portion 743 elastically holds the metal wire 739. The metal wire 739 protrudes with respect to the upper surface (that is, the second surface) of the second conductive portion 692. A groove 747 that is complementary to the bent portion of the metal wire 739 is formed in the first conductive portion 742 of the reinforcing plate 740. The metal wire 739 is inserted into the groove portion 747 and is electrically connected between the first transport device 610 and the second transport device 620 or between the second transport device 620 and the housing 2 of the image forming apparatus 1. The connection is preferably carried out. Further, as described above, since the metal wire 739 is elastically supported by the third conductive portion 743, damage to the metal wire 739 can be suppressed even when the metal wire 739 is not properly fitted in the groove portion 747. It becomes.

  The present invention can be applied to a printer, a copier, a facsimile machine, a multifunction machine having these functions, and various apparatuses for forming an image on a sheet.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Housing | casing 410 ... Image forming part 600 ... Conveying apparatus 610 ... 1st conveying apparatus 620 ... 2nd conveying apparatus 641 ... Inlet port 642 ... Discharge port 643 ... first surface 644 ... second surface 690 ... conductive structure 692 ... second conductive portion 700 ... guide portion 711 ... first guide surface (Guidance surface)
712 ... Reinforcing surface 731 ... Shaft 733 ... Follower roller (conveyance roller)
740 ... Reinforcing plate 742 ... 1st conductive part 743 ... 3rd conductive part 744 ... 4th conductive part 745 ... 5th conductive part 746 ... Ground wire

Claims (3)

A first conveying device and a second conveying device which are formed to convey sheets and are stacked on each other;
The first transport device and the second transport device are:
A frame including a first surface on which an introduction port into which a sheet is introduced is formed, and a second surface on which the discharge port from which the sheet is discharged is formed and opposite to the first surface;
A guide portion having a resin-made guide surface for guiding the sheet from the introduction port toward the discharge port, and a reinforcing surface opposite to the guide surface;
A reinforcing plate connected to the reinforcing surface and extending in the width direction of the sheet;
A conductive structure for conducting static electricity in the frame body,
The reinforcing plate includes a first conductive part exposed on the first surface,
The conductive structure includes a second conductive portion exposed on the second surface, and a third conductive portion connecting the first conductive portion and the second conductive portion,
The second transport device is disposed so that the first surface of the second transport device is adjacent to the second surface of the first transport device, and the discharge port of the first transport device and the second surface 2 communicate with the introduction port of the transport device,
The transport unit, wherein the second conductive portion of the first transport device is electrically connected to the first conductive portion of the second transport device. A transport roller for transporting the sheet guided by the guide surface toward the discharge port;
A conductive shaft that supports the transport roller, and
The transport unit according to claim 1, wherein the conductive structure includes a fourth conductive portion that electrically connects the shaft and the second conductive portion. An image forming unit for forming an image on a sheet;
A housing that houses the image forming unit;
A first conveying device and a second conveying device formed to convey the sheet in the housing and stacked on each other;
The second transport device is disposed between the housing and the first transport device,
The first transport device and the second transport device are:
A frame including a first surface on which an introduction port into which a sheet is introduced is formed, and a second surface on which the discharge port from which the sheet is discharged is formed and opposite to the first surface;
A guide portion having a resin-made guide surface for guiding the sheet from the introduction port toward the discharge port, and a reinforcing surface opposite to the guide surface;
A reinforcing plate connected to the reinforcing surface and extending in the width direction of the sheet;
A conductive structure for conducting static electricity in the frame body,
The reinforcing plate includes a first conductive part exposed on the first surface,
The conductive structure includes a second conductive portion exposed on the second surface, and a third conductive portion connecting the first conductive portion and the second conductive portion,
The second transport device is disposed so that the first surface of the second transport device is adjacent to the second surface of the first transport device, and the discharge port of the first transport device and the second surface 2 communicate with the introduction port of the transport device,
The second conductive portion of the first transport device is electrically connected to the first conductive portion of the second transport device;
The housing includes a fifth conductive part electrically connected to the second conductive part of the second transfer device, and a ground wire electrically connected to the fifth conductive part. An image forming apparatus.

Images