JP2014189345A - Conveying apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveying apparatus and an image forming apparatus capable of suppressing occurrence of noise associated with conveyance.SOLUTION: An image forming apparatus has: a resist roller 700 which conveys a paper P; a feed roller 710 which feeds the paper P toward the resist roller 700; and at least one of a first nip pressure adjustment mechanism 810 and a second nip pressure adjustment mechanism 820 which adjusts at least one of speed at which the resist roller 700 conveys the paper P and speed at which the feed roller 710 feeds the paper P such that flexure created in the paper P between the resist roller 700 and the feed roller 710 is eliminated at the point where a rear end of the paper P passes the feed roller 710.

Description

  The present invention relates to a conveyance device and an image forming apparatus.

  Patent Document 1 describes a sheet conveying apparatus including the following structural requirements (A01) to (A03). (A01) A registration roll for conveying a recording sheet to an image recording area where an image is recorded, (A02) a pre-registration roll arranged upstream of the registration roll in the sheet conveyance direction, and the recording sheet is stopped on the registration roll (A03) A pre-registration roll drive device that rotationally drives the pre-registration roll at a sheet conveyance speed less than the sheet conveyance speed of the registration roll.

  In Patent Document 2, a pair of conveyance rollers having a nip portion arranged on a conveyance path of a sheet material, and a front end portion of the sheet material about to enter the nip portion, the sheet material is moved with a predetermined stopping force. And a shutter unit having a contact portion that is retracted from the conveyance path by the conveyance force of the abutted sheet material, and a conveyance unit that conveys the sheet material toward the conveyance roller pair. The sheet material conveying speed of the conveying means is the same as or smaller than the sheet material conveying speed of the conveying roller pair, and the conveying roller pair and the conveying means until the rear end portion of the sheet material passes the conveying means. The sheet material conveying apparatus is characterized in that it is set to a speed at which the loop of the sheet material formed during the period can be maintained.

JP 2006-56658 A JP-A-11-139626

  SUMMARY An advantage of some aspects of the invention is that it provides a conveyance device and an image forming apparatus that can suppress generation of sound accompanying conveyance.

  The present invention according to claim 1 is arranged on the upstream side of the transport member in the transport direction of the transport target and the transport member, and supplies the transport target toward the transport member. The supply member, and the bend formed on the transfer object between the supply member and the transfer member is eliminated when the rear end of the transfer object passes through the supply member. An adjustment unit that adjusts at least one of a speed at which the conveyance object is conveyed and a speed at which the supply member supplies the conveyance object.

  The present invention according to claim 2 is arranged so as to sandwich the conveyance object between the first contact member and the supply member which are arranged so as to sandwich the conveyance object between the conveyance member. At least one of the second contact members, and the adjusting means presses the force against which the first contact member and the transport member are pressed, and the second contact member and the supply member press against each other. The conveying device according to claim 1, wherein at least one of the applied forces is adjusted.

  The present invention according to claim 3 is characterized in that the adjusting means is at least one of a speed at which the transport member transports the transport target object and a speed at which the supply member supplies the transport target object according to the thickness of the transport target object. It is a conveying apparatus of Claim 1 or 2 which adjusts one side.

  According to a fourth aspect of the present invention, the adjusting means includes: a speed at which the conveyance member conveys the conveyance object according to a length of the conveyance object in a direction in which the conveyance object is conveyed; It is a conveying apparatus in any one of Claims 1 thru | or 3 which adjusts at least any one of the speed | rates which supply a thing.

  The present invention according to claim 5 is characterized in that the adjusting means is at least one of a speed at which the conveying member conveys the object to be conveyed and a speed at which the supply member supplies the object to be conveyed according to the number of objects to be conveyed. It is a conveying apparatus in any one of Claims 1 thru | or 4 which adjusts any one.

  According to a sixth aspect of the present invention, there is provided an image forming unit that forms an image on a recording medium, a conveying member that conveys an object to be conveyed toward the image forming unit, and an upstream side of the conveying member in the conveying direction of the recording medium. And a supply member that supplies the recording medium toward the conveying member, and a flexure formed in the recording medium between the supply member and the conveying member is a trailing end of the recording medium. An adjusting unit that adjusts at least one of a speed at which the transport member transports the recording medium and a speed at which the supply member supplies the recording medium so as to be eliminated at the time of passing the recording medium. is there.

  According to the first aspect of the present invention, it is possible to provide a transport device that can suppress the generation of sound associated with the transport of the transport object as compared with the case where the present configuration is not provided.

  According to the second aspect of the present invention, it is possible to provide a transport apparatus that can suppress the generation of sound associated with the transport of the transport object with a simple structure as compared with the case where the present structure is not provided.

  According to this invention which concerns on Claim 3, even if the thickness of a conveyance target object changes, the conveying apparatus which can suppress generation | occurrence | production of the sound accompanying conveyance of a conveyance target object can be provided.

  According to this invention which concerns on Claim 4, even if the length of a conveyance target object changes, the conveying apparatus which can suppress generation | occurrence | production of the sound accompanying conveyance of a conveyance target object can be provided.

  According to this invention which concerns on Claim 5, even if the number of the conveyed conveyance object changes, the conveying apparatus which can suppress generation | occurrence | production of the sound accompanying conveyance of a conveyance object can be provided.

  According to the sixth aspect of the present invention, it is possible to provide an image forming apparatus capable of suppressing the generation of sound accompanying the conveyance of the recording medium, as compared with the case where the present configuration is not provided.

1 is a diagram illustrating a cross section viewed from the front side of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a cross section viewed from the front side of an image forming unit included in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram illustrating configurations of a conveyance member, a supply member, a first contact member, and a second contact member included in the image forming apparatus illustrated in FIG. 1 and configurations in the vicinity of these members. FIG. 4 is a diagram illustrating a driving mechanism that drives a conveyance member and a supply member included in the image forming apparatus illustrated in FIG. 1 from the direction of an arrow AA illustrated in FIG. 3. FIG. 4 is a diagram illustrating a configuration of an adjustment unit included in the image forming apparatus illustrated in FIG. 1 from the direction of arrow BB illustrated in FIG. 3. 2 is a graph showing the relationship between the type of paper used in the image forming apparatus shown in FIG. 1 and the amount of loop formed between a supply member and a conveyance member. 3 is a graph showing a relationship between a nip pressure between a supply member and a second contact member in the image forming apparatus shown in FIG. 1 and a speed at which a sheet is supplied. FIG. 2 is a block diagram illustrating a controller included in the image forming apparatus illustrated in FIG. 1. 3 is a flowchart for explaining the operation of the image forming apparatus shown in FIG. 1. FIG. 10A is a first diagram illustrating a state of a sheet in an image forming apparatus according to a comparative example of the present invention, and FIG. 10A is a time point when a rear end portion of the sheet passes through a contact portion between a supply member and a driven member. FIG. 10B is a diagram illustrating the state of the sheet after a predetermined time has elapsed from the time illustrated in FIG. 10A. FIG. 11A is a second diagram illustrating a state of a sheet in an image forming apparatus according to a comparative example of the present invention, and FIG. 11A is a time point when a rear end portion of the sheet passes through a contact portion between a supply member and a driven member. FIG. 11B is a diagram showing the state of the paper after a predetermined time has elapsed from the time shown in FIG. 11A. FIG. 12A is a third diagram illustrating the state of the sheet in the image forming apparatus according to the comparative example of the present invention, and FIG. 12A illustrates the trailing end of the sheet passing through the contact portion between the supply member and the second driven member. FIG. 11B is a diagram illustrating the state of the sheet immediately after the trailing end of the sheet passes through the contact portion between the supply member and the second driven member.

Next, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, and the controller 20, the communication device 22, the image forming unit 100, the optical scanning device 260, and the paper feeding used as a control unit are included in the image forming apparatus main body 12. A device 400 is arranged. An original reading apparatus 500 and an operation panel 30 used as an operation unit are mounted on the upper part of the image forming apparatus main body 12, and image formation is completed on the right side surface of the image forming apparatus main body 12. A discharge hole 14 for discharging the paper P to the outside of the image forming apparatus main body 12 is formed. Here, the paper P is used as a transport object that is a transport target, and is also used as a recording medium on which an image is recorded.

  Further, a discharge tray 16 on which the paper P discharged from the image forming apparatus main body 12 through the discharge holes 14 is mounted is mounted on the right side surface of the image forming apparatus main body 12. In addition, a conveyance path 600 that is a conveyance path for conveying the paper P is formed in the image forming apparatus main body 12. The image forming apparatus 10 has a printer function for printing image data received from a computer terminal or the like connected via a network or the like, and also functions as a scanner, a copier, and a facsimile. It is what has.

  The operation panel 30 is used for inputting, for example, the number of sheets P to be output and the types of sheets P for forming images such as plain paper and thick paper.

  The document reader 500 is placed on a glass plate 502 on which a document D on which an image to be read is written is placed, a cover member 504 that presses the document D against the glass plate 502, and the glass plate 502. And a reading optical unit 510 that reads an image written on the document D. The reading optical unit 510 is configured to illuminate a document D placed on the glass plate 502 with a light source 512 and read a reflected light image from the document D with an image reading element 514 through a mirror group and a lens. Yes. Image data read by the document reading apparatus 500 is output to the controller 20.

  The controller 20 determines in advance such as shading correction, document position shift correction, gamma correction, frame erasing, color / movement editing, and the like for image data read by the document reading device 500 or image data received from a computer terminal or the like. The obtained image processing is performed. Further, the controller 20 counts the number of sheets P on which an image has been formed since the start of use of the image forming apparatus 10 based on, for example, the number of times image data is input, and this value is illustrated in FIG. Is stored in the storage unit, and the value stored in the storage unit can be read.

  The communication device 22 receives image data from, for example, a computer terminal and outputs the received image data to the controller 20.

  The image forming unit 100 forms an image based on the image data output from the controller 20, and includes, for example, four image forming units 110Y, an image forming unit 110M, an image forming unit 110C, and an image forming unit 110K. Furthermore, a transfer device 300 is provided. The image forming unit 110M, the image forming unit 110C, and the image forming unit 110K are each used for forming a yellow image, used for forming a magenta image, and used for forming a cyan image. , Used to form a black image. Further, the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K each include a photoconductive drum 112Y, a photoconductive drum 112M, a photoconductive drum 112C, and a photoconductive drum 112K.

  Each of the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K is used as an image holding body that holds a toner image. Details of the image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K will be described later.

  The optical scanning device 260 is a device that scans light based on image data output from the controller 20, and includes, for example, four optical scanning units 262Y, an optical scanning unit 262M, an optical scanning unit 262C, and an optical scanning unit 262K. . The optical scanning unit 262Y, the optical scanning unit 262M, the optical scanning unit 262C, and the optical scanning unit 262K irradiate light to the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, respectively. And used as a latent image forming apparatus for forming an electrostatic latent image.

  The transfer device 300 includes an intermediate transfer belt 302. The intermediate transfer belt 302 is in contact with the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, and the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K, for example. The toner images are transferred from the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K while moving with a difference in peripheral speed.

  The intermediate transfer belt 302 is band-shaped and endless, and is formed, for example, by forming a flexible synthetic resin film such as polyimide in a band shape and connecting both ends of the formed synthetic resin film by welding or the like. Can be used.

  Further, the intermediate transfer belt 302 is wound around the support roller 310, the support roller 312, the support roller 314, the support roller 316, the support roller 318, and the support roller 320, which are, for example, six support rollers. Is supported. At least one of the six support rollers is used as a drive transmission member that transmits drive to the intermediate transfer belt 302. In this embodiment, the support roller 310 is used as a drive transmission member, and the intermediate transfer belt is moved in the direction of arrow a by rotating the support roller 310 in response to drive transmission from a drive motor (not shown). Driven to rotate.

  In addition, the transfer device 300 includes, for example, four primary transfer rollers 330Y, a primary transfer roller 330M, a primary transfer roller 330C, and a primary transfer roller 330K, which are primary transfer rollers. The primary transfer roller 330Y, the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K are respectively an intermediate transfer belt from the photosensitive drum 112Y, the photosensitive drum 112M, the photosensitive drum 112C, and the photosensitive drum 112K. It is used as a transfer member (primary transfer member) to which a transfer voltage for transferring a toner image is applied to 302.

  The transfer device 300 includes a secondary transfer roller 390. The secondary transfer roller 390 is used as a transfer member (secondary transfer member) for transferring a toner image from the intermediate transfer belt 302 to the paper P, and is pressed against the support roller 318 via the intermediate transfer belt 302. It has been.

  In addition, the transfer device 300 includes a cleaning device 394. The cleaning device 394 cleans the intermediate transfer belt 302 by removing toner remaining on the surface of the intermediate transfer belt 302 after the toner image is transferred onto the paper P by the secondary transfer roller 390.

  The paper feeding device 400 is a device that supplies the paper P to the conveyance path 600, and includes a storage container 402 that stores the paper P so as to be stacked, and a paper P that is stacked on the storage container 402. And a delivery roller 404 that feeds the uppermost sheet P to the conveyance path 600.

  The storage container 402 can be taken out from the image forming apparatus main body 12. A plurality of storage containers 402 are prepared, and each storage container 402 stores, for example, paper P having different thicknesses and a plurality of types of paper P having different sizes. Therefore, by replacing the storage container 402 attached to the image forming apparatus main body 12, a desired paper P can be selected from a plurality of types of paper P having different thicknesses and sizes, for example, and an image can be formed. Instead of preparing a plurality of storage containers 402 storing a plurality of different types of paper P, or preparing a plurality of storage containers 402 storing a plurality of types of paper P, A plurality of storage containers 402 storing different types of paper P may be attached to the image forming apparatus main body 12.

  A container sensor 410 that detects which storage container 402 of the plurality of storage containers 402 is mounted on the image forming apparatus main body 12 is provided in the vicinity of the storage container 402 in the image forming apparatus main body 12. The output from the container sensor 410 is input to the controller 20, and the controller 20 determines the thickness and size of the paper P on which an image is formed.

  The transport path 600 is a transport path for transporting the paper P from the paper feeding device 400 to the discharge tray 16, and the above-described delivery roller 404 and the above-described transport rollers 600 in order from the upstream side in the transport direction of the paper P along the transport path 600. The transfer roller 610, the transfer roller 612, the supply roller 710 and the second driven roller 730, the registration roller 700 and the first driven roller 720, the support roller 318 and the secondary transfer roller 390, and the transfer device 620. A conveying device 630 and a fixing device 180 are disposed.

  In the present embodiment, the supply roller 710 is disposed upstream of the registration roller 700 in the conveyance direction of the paper P, and is used as a supply member that supplies the paper P toward the registration roller 700. The second driven roller 730 is used as a second contact member that contacts the supply roller 710 and is disposed so as to sandwich the paper P between itself and the supply roller 710, and is driven by the rotation of the supply roller 710. It is designed to rotate as you do.

  In this embodiment, the registration roller 700 is used as a conveying member that conveys the paper P toward the image forming unit 100. Further, in a stopped state, the registration roller 700 temporarily stops the movement of the leading end portion of the paper P that is being sent toward the downstream side in the transport direction by the supply roller 710, and the image forming unit 110Y and the image forming unit A toner image formed by the unit 110M, the image forming unit 110C, and the image forming unit 110K and transferred to the intermediate transfer belt 302 by the primary transfer roller 330Y, the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K. The sheet P is conveyed so that the movement of the leading end of the sheet P is resumed so as to coincide with the timing when the toner reaches the contact portion between the secondary transfer roller 390 and the intermediate transfer belt 302.

  The first driven roller 720 is in contact with the registration roller 700 and is used as a first contact member that sandwiches the paper P between itself and the registration roller 700, and rotates so as to follow the rotation of the registration roller 700. It has become. Details of the registration roller 700, the supply roller 710, the first driven roller 720, and the second driven roller 730 will be described later.

  A sheet sensor in the vicinity of the conveyance path 600 and upstream of the supply roller 710 and the second driven roller 730 in the conveyance direction of the sheet P, instead of the container sensor 410 described above or in combination with the container sensor 410 described above. 640 may be provided. The paper sensor 640 is a sensor that detects the thickness of the paper P being transported through the transport path 600 and the length of the paper P being transported through the transport path 600 in the paper transport direction. The output from the paper sensor 640 is input to the controller 20, and the controller 20 determines the thickness of the paper P on which the image is formed and the size of the paper.

  The transport device 620 and the transport device 630 are configured to transfer the paper P in a state where the toner image is transferred to the upper surface in the gravity direction and the unfixed toner image is placed on the upper surface in the gravity direction on the lower side in the gravity direction. Then, the toner is conveyed toward the fixing device 180 while being supported. The fixing device 180 fixes the toner image placed on the upper surface of the paper P to the upward surface of the paper P using, for example, heat and pressure.

  FIG. 2 shows an image forming unit 110Y, an image forming unit 110M, an image forming unit 110C, and an image forming unit 110K. The image forming unit 110Y, the image forming unit 110M, the image forming unit 110C, and the image forming unit 110K have the same configuration although the color of the toner to be used and the color of the toner image to be formed are different. Therefore, these image forming units will be collectively referred to as the image forming unit 110 below. 2 shows a primary transfer roller 330Y, a primary transfer roller 330M, a primary transfer roller 330C, and a primary transfer roller 330K. Since the primary transfer roller 330M, the primary transfer roller 330C, and the primary transfer roller 330K have the same configuration, these primary transfer rollers will be collectively referred to as the primary transfer roller 330 below.

  As shown in FIG. 2, the image forming unit 110 makes the surface of the photosensitive drum 112 uniform before forming the latent image on the photosensitive drum 112 by the optical drum 260 and the optical drum 260 described above. A charging device 120 for charging the toner and a toner image forming unit for forming a toner image on the photosensitive drum 112. The latent image formed on the surface of the photosensitive drum 112 by the optical scanning device 260 is used with toner. The developing device 130 for developing and the surface of the photosensitive drum 112 are cleaned, and the toner remaining on the surface of the photosensitive drum 112 after the transfer of the toner image onto the intermediate transfer belt 302 by the primary transfer roller 330 is completed is removed. Device 140.

  FIG. 3 shows a registration roller 700, a supply roller 710, a first driven roller 720, and a second driven roller 730. The material of at least the surface portion of the registration roller 700 is an elastic body such as rubber. Therefore, when the first driven roller 720 is pressed against the registration roller 700, at least the position where the registration roller 700 is in contact with the first driven roller 720 is elastically deformed. Further, the supply roller 710 is made of an elastic body such as rubber at least on the surface portion. Therefore, when the second driven roller 730 is pressed against the supply roller 710, at least the position where the supply roller 710 is in contact with the second driven roller 730 is elastically deformed.

  As shown in FIG. 3, a motor 740 used as a drive source is connected to the registration roller 700 and the supply roller 710 via a drive transmission mechanism 742. When the drive from the motor 740 is transmitted by the drive transmission mechanism 742, the registration roller 700 and the supply roller 710 rotate in the directions indicated by the arrows in FIG. Further, the first driven roller 720 rotates in the direction indicated by the arrow in FIG. 3 by following the registration roller 700, and the second driven roller 730 is indicated by the arrow in FIG. 3 by following the supply roller 710. Rotate in the direction that is being done. The details of the drive transmission mechanism 742 will be described later.

  The first driven roller 720 is provided with a first nip pressure adjusting mechanism 810. The first nip pressure adjustment mechanism 810 adjusts the force with which the first driven roller 720 and the registration roller 700 are pressed, and adjusts the pressure at the nip portion N1 formed between the first driven roller 720 and the registration roller 700. To do. The second driven roller 730 is provided with a second nip pressure adjusting mechanism 820. The second nip pressure adjusting mechanism 820 adjusts the force with which the second driven roller 730 and the supply roller 710 are pressed, and adjusts the pressure at the nip portion N2 formed between the second driven roller 730 and the supply roller 710. To do.

  The first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820 are a speed at which the registration roller 700 conveys and moves the paper P, and a speed at which the supply roller 710 conveys the paper P, and the supply roller 710 It is used as an adjusting means for adjusting at least one of the speed at which P is supplied to the registration roller 700. Since the image forming apparatus 10 includes the first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820, the force by which the first driven roller 720 and the registration roller 700 are pressed, the second driven roller 730, the supply roller 710, and the like. It is possible to adjust at least one of the forces with which the is pressed. Details of the first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820 will be described later.

  As described above, the registration roller 700 once stops the movement of the leading end of the paper P that is being fed toward the downstream side in the transport direction by the supply roller 710. For this reason, as shown in FIG. 3, the sheet P is bent (looped), for example, downward at a position between the supply roller 710 and the driven roller 730 and the registration roller 700 and the first driven roller 720. The

  FIG. 4 shows a registration roller 700, a supply roller 710, and a drive transmission mechanism 742. The drive transmission mechanism 742 has a speed reducer 744. The reduction device 744 includes, for example, a gear train having a plurality of gears, and transmits the drive from the motor 740 to the registration roller 700 and the supply roller 710 while reducing the drive at a predetermined reduction ratio. For example, the gear ratio is set so that the peripheral speed of the registration roller 700 is larger than the peripheral speed of the supply roller 710 as the reduction ratio for transmitting the drive to the registration roller 700 and the transmission ratio of the drive for transmitting the drive to the supply roller 710. It is determined by doing.

  The drive transmission mechanism 742 includes a first clutch device 752 and a second clutch device 754. The first clutch device 752 uses, for example, an electromagnetic clutch, and is controlled by an output from the controller 20 (see FIG. 1) to transmit the drive from the motor 740 to the registration roller 700, and from the motor 740 to the registration roller. The drive transmission to 700 is cut off. The second clutch device 754 uses, for example, an electromagnetic clutch, similarly to the first clutch device 752, and is controlled by the output from the controller 20 to transmit the drive from the motor 740 to the supply roller 710. The transmission of drive from 740 to the supply roller 710 is cut off.

  In this image forming apparatus 10, the timing at which the first clutch device 752 is turned on / off, the timing at which the second clutch device 752 is turned on / off, the reduction ratio of the drive transmitted to the registration roller 700, and the drive transmitted to the supply roller 710. The reduction ratio is the deflection formed on the sheet P when the registration roller 700 starts rotating when the sheet P having the size and thickness most frequently used in the image forming apparatus 10 is used (see FIG. 3). (Refer to paper P) is determined to be eliminated just when the trailing edge of the paper P passes through the nip portion N2.

  FIG. 5 shows a supply roller 710, a second driven roller 730, and a second nip pressure adjusting mechanism 820. As shown in FIG. 5, the shaft portion of the supply roller 710 has a bearing 712 a near the front end (left side in FIG. 5) and a bearing 712 b near the rear end (right side in FIG. 5). It is installed. Then, the bearing 712a is fixed to the side plate 12a forming a part of the image forming apparatus main body 12, and the bearing 712b is fixed to the side plate 12b forming a part of the image forming apparatus main body 12, whereby the supply roller 710 is connected to the image forming apparatus main body 12. The main body 12 is mounted so as to be able to rotate.

  The shaft portion of the second driven roller 730 is provided with a bearing 732a at the front end and a bearing 732b at the rear end. The side plate 12a has a long hole 12c extending in the vertical direction, for example, and the side plate 12b has a long hole 12d extending in the vertical direction, for example. Then, the bearing 732a is inserted into the long hole 12c and the bearing 732b is inserted into the long hole 12d so that the second driven roller 730 is in the longitudinal direction of the long hole 12c and the long hole 12d with respect to the image forming apparatus main body 12. Is supported so that it can be moved to. Here, the long hole 12 c and the long hole 12 d are formed in a direction in which the second driven roller 730 can approach the supply roller 710 and the second driven roller 730 can move away from the supply roller 710.

  The second nip pressure adjustment mechanism 820 includes a motor 822 and a cam mechanism 824. As shown in FIG. 5, the cam mechanism 824 has a shaft member 826, and a bearing 828 a is mounted on the front end side of the shaft member 826, and the rear end side of the shaft member 826 Is mounted with a bearing 828b. The shaft member 826 is mounted so as to be rotatable with respect to the image forming apparatus main body 12 by mounting the bearing 828a on the side plate 12a and mounting the bearing 828b on the side plate 12b. Further, a motor 822 is connected to the shaft member 826, and the shaft member 826 rotates in response to drive transmission from the motor 822.

  The motor 822 is controlled by the output from the controller 20.

  Further, the cam member 830a is mounted on the shaft member 826 on the front end side so as to face the bearing 732a, and the cam member 830b is mounted on the rear end side so as to face the bearing 732b. ing. In the cam mechanism 824, when the shaft member 826 rotates, the distance between the bearing 732a end of the cam member 830a and the bearing 732a, and the distance between the bearing 732b end of the cam member 830b and the bearing 732b change. .

  The cam mechanism 824 includes, for example, an elastic member 832a made of a coil spring or the like, and an elastic member 832b also made of a coil spring or the like. One end of the elastic member 832a is fixed to the bearing 732a, and the other end of the elastic member 832a is in contact with the cam member 830a. One end of the elastic member 832b is fixed to one end of the bearing 732b, and the other end of the elastic member 832b is in contact with the cam member 830b.

  In the second nip pressure adjusting mechanism 820, when the shaft member 826 is rotated by receiving the drive transmission from the motor 822, the bearing 732a is guided to the long hole 12c, and the bearing 732b is guided to the long hole 12d. The elastic member 832a, the elastic member 832b, the bearing 732a, the bearing 732b, and the second driven roller 730 move in the vertical direction. Then, as the driven roller 730 moves up and down, the distance between the second driven roller 730 and the supply roller 710 changes. Then, by changing and adjusting the distance between the second driven roller 730 and the supply roller 710, the second nip pressure adjusting mechanism 820 adjusts the force with which the second driven roller 730 and the supply roller 710 are pressed, 2 The pressure in the nip portion N2 formed between the driven roller 730 and the supply roller 710 is adjusted.

  The first nip pressure adjusting mechanism 810 (see FIG. 3) has the same configuration as the second nip pressure adjusting mechanism 820 described above. That is, in the same manner as the second driven roller 730 is moved in the second nip pressure adjusting mechanism 820, the first driven roller 720 is moved in the first nip pressure adjusting mechanism 810 so that the first driven roller 720 and the registration are moved. The force with which the roller 700 is pressed is adjusted, and the pressure at the nip portion N1 formed between the first driven roller 720 and the registration roller 700 is adjusted.

  FIG. 6 shows the relationship between the thickness of the paper P used in the image forming apparatus 10 and the loop amount (amount of deflection) formed on the paper P between the supply roller 710 and the registration roller 700. . Here, the loop amount formed on the paper P between the supply roller 710 and the registration roller 700 is the length in the transport direction of the paper P located between the nip portion N1 and the nip portion N2, and the nip portion. The length obtained by subtracting the linear distance between N1 and the nip portion N2 is used.

  As shown in FIG. 6, it can be seen that the loop amount when thick paper is used as the paper P is smaller than that when plain paper is used as the paper P, and the loop amount becomes smaller as the paper P is thicker. The thicker the paper P is, the smaller the loop amount is because the rigidity of the paper (paper stiffness) is larger as the paper is thicker, so that the front end of the paper P passes through the nip portion N2 and the front end of the paper P is registered. This is because the amount by which the paper P hangs down in the direction of gravity before contacting the roller 700 or the driven roller 720 is small.

  FIG. 7 shows the relationship between the pressure (nip pressure) at the nip portion N2 formed by the supply roller 710 and the second driven roller 730 in the image forming apparatus 10 and the speed at which the paper P is conveyed. . Here, the angular velocity of the supply roller 710 that rotates in response to drive transmission from the motor 740 is constant regardless of the nip pressure. As shown in FIG. 7, it can be seen that the speed at which the paper P is transported increases as the nip pressure increases, and the speed at which the paper P transports decreases as the nip pressure decreases. This is because the larger the nip pressure, the larger the distortion of the supply roller 710 due to elastic deformation so that the surface of the supply roller 710 is crushed, and the peripheral length of the supply roller 710 is locally at the position where the nip portion N2 is formed. This is because it becomes longer.

  Similar to the relationship between the nip pressure at the nip portion N2 and the speed at which the paper P is conveyed shown in FIG. 7, the speed at which the paper P is conveyed increases at the nip portion N1 as the nip pressure is increased. The smaller the speed, the slower the speed at which the paper P is conveyed.

  FIG. 8 is a block diagram showing the controller 20. As shown in FIG. 8, the controller 20 receives an output from the container sensor 410, an output from the paper sensor 640, and an output from the operation panel 30. In addition, the first clutch device 752, the second clutch device 754, the first nip pressure adjusting mechanism 810, and the second nip pressure adjusting mechanism 820 are controlled by the output from the controller 20.

  FIG. 9 is a flowchart for explaining the operation of the image forming apparatus 10. When the motor 740 starts rotating and a series of controls for conveying the paper P as shown in FIG. 9 is started, in step S10, the controller 20 detects the nip pressure and nip of the nip portion N1. Whether at least one of the speed at which the supply roller 710 supplies the paper P and the speed at which the registration roller 700 transports the paper P needs to be adjusted by adjusting at least one of the nip pressures of the portion N2. Is determined.

  In other words, the controller 20 determines that the paper P transported one sheet before and the paper P transported from now on are based on the output from any of the container sensor 410, the paper sensor 640, and the operation panel 30. If these sheets P are the same type of sheet, the controller 20 determines that the adjustment of the nip pressure is unnecessary. On the other hand, if the type of the paper P transported one sheet before and the paper P to be transported are different and the thickness of the paper P is different, the controller 20 needs to adjust the nip pressure. Determine. For example, when the sheet P transported one sheet before is plain paper and the sheet P transported from now on is a thick sheet, the thickness of the sheet P transported from now on is different from that of the sheet P transported from now on. In this case, the controller 20 determines that the nip pressure needs to be adjusted.

  If the controller 20 determines that nip pressure adjustment is necessary, the process proceeds to step S20. If the controller 20 determines that nip pressure adjustment is not necessary, the process proceeds to step S30.

  In step S20, the controller 20 controls at least one of the first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820, and the speed at which the supply roller 710 supplies the paper P and the registration roller 700 the paper P At least one of the speeds at which the sheet is conveyed. For example, the paper P transported one sheet before and the paper P to be transported from now on have the same size, but the paper P transported one sheet before is plain paper and is about to be transported from now on. When the paper P is a thick paper, the controller 20 causes the first nip pressure adjusting mechanism 810 to reduce the pressure at the nip portion N1, and slows the speed at which the registration roller 700 conveys the paper P. Further, instead of decreasing the pressure at the nip portion N1 to the first nip pressure adjusting mechanism 810 and reducing the speed at which the registration roller 700 conveys the paper P, the pressure at the nip portion N1 is changed to the first nip pressure adjusting mechanism 810. The speed at which the supply roller 710 supplies the paper P by increasing the pressure at the nip portion N2 to the second nip pressure adjusting mechanism 820 in conjunction with reducing the speed at which the registration roller 700 conveys the paper P. May be made faster.

  In the control described as an example here, when the plain paper which is the previous sheet P is conveyed, the loop of the sheet P formed between the nip portion N2 and the nip portion N1 is The speed at which the registration roller 700 conveys the paper P is adjusted by adjusting the pressure at the nip portion N1, so that the pressure at the nip portion N2 is adjusted so that the rear end portion of the P passes through the nip portion N2. Is adjusted, the speed at which the supply roller 710 supplies the paper P is set. Therefore, if the thick paper is to be transported in this state, the loop formed on the thick paper is smaller than the loop formed on the plain paper, so that the thick paper does not pass before the rear end of the thick paper passes through the nip portion N2. It will be in the state where the loop was canceled.

  For this reason, in step S10, the controller 20 determines that at least one of the speed at which the supply roller 710 supplies the paper P and the speed at which the registration roller 700 transports the paper P as described above, Adjustment is made so that the loop formed on the cardboard is eliminated when it passes N2.

  Further, for example, the paper P transported one sheet before and the paper P to be transported from now on have the same size, but the paper P transported one sheet before is a thick paper, and is going to be transported from now on. When the sheet P is plain paper, the controller 20 causes the first nip pressure adjustment mechanism 810 to increase the pressure at the nip portion N1 and increase the speed at which the registration roller 700 conveys the sheet P. Further, instead of increasing the pressure at the nip portion N1 to the first nip pressure adjusting mechanism 810 to increase the speed at which the registration roller 700 conveys the paper P, the pressure at the nip portion N1 is applied to the first nip pressure adjusting mechanism 810. In addition to increasing the speed at which the registration roller 700 conveys the paper P by increasing the pressure, the speed at which the supply roller 710 supplies the paper P by causing the second nip pressure adjusting mechanism 820 to reduce the pressure at the nip portion N2. May be delayed.

  In the control described as an example here, when a thick sheet, which is the previous sheet P, is transported, a loop of the sheet P formed between the nip portion N2 and the nip portion N1 is formed by the sheet P. The speed at which the registration roller 700 conveys the paper P is adjusted by adjusting the pressure in the nip portion N1, so that the pressure at the nip portion N2 is adjusted so that the pressure at the nip portion N2 is adjusted so that the rear end portion just disappears. By adjusting, the speed at which the supply roller 710 supplies the paper P is set. Therefore, if the plain paper is conveyed in this state, the loop formed on the plain paper is larger than the loop formed on the thick paper, and the plain paper is passed when the trailing edge of the plain paper passes through the nip portion N2. In this state, the loop formed in (2) is not eliminated, and the trailing edge of the plain paper passes through the nip portion N2 while the rope is still formed.

  For this reason, in step S10, as described above, the controller 20 forms at least one of the speed at which the supply roller 710 supplies the paper P and the speed at which the registration roller 700 transports the paper P on the plain paper. The loop is adjusted so as to be eliminated when the trailing edge of the plain paper passes through the nip portion N2.

  In step S30, the controller 20 controls the second clutch device 754 to drive the supply roller 710 at a predetermined timing, and to start supplying the paper P to the supply roller 710 at a predetermined timing.

  In step S40, the controller 20 controls the first clutch device 752, drives the registration roller 700 at a predetermined timing, and causes the registration roller 700 to start conveying the paper P at a predetermined timing.

  In the above description, the control when the size of the paper P transported one sheet before and the paper P to be transported is the same has been described, but the paper P transported one sheet before. When the length of the paper P in the transport direction of the paper P is different between the paper P to be transported and the paper P to be transported from now on, when the trailing edge of the paper P passes through the nip portion N2 according to the size of the paper P. The controller 20 controls at least one of the first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820 so that the loop formed on the paper P is eliminated, and the supply roller 710 At least one of the feeding speed and the speed at which the registration roller 700 transports the paper P is adjusted.

  Further, at least one of the first nip pressure adjusting mechanism 810 and the second nip pressure adjusting mechanism 820 is controlled and supplied in accordance with the number of sheets P transported since the start of use of the image forming apparatus 10. Control may be performed so that at least one of the speed at which the roller 710 supplies the paper P and the speed at which the registration roller 700 transports the paper P is adjusted. Accordingly, even if the speed at which the supply roller 710 supplies the paper P changes due to the deterioration of the supply roller 710 or the speed at which the registration roller 700 conveys the paper P changes due to the deterioration of the registration roller 700, the paper P It is possible to control so that the loop formed on the paper P is eliminated when the rear end of the paper passes the nip portion N2.

  FIG. 10 is a first diagram for explaining the state of the paper P in the image forming apparatus according to the comparative example of the present invention. FIG. 10A shows the contact between the supply roller and the driven roller at the rear end of the paper P. FIG. FIG. 10B shows the state of the paper P after a predetermined time has elapsed from the time shown in FIG. 10A.

  In the image forming apparatus 10 according to the embodiment of the present invention, as described above, control is performed so that the loop formed on the paper P is eliminated when the trailing end of the paper P passes through the nip portion N2. It was. On the other hand, in the image forming apparatus according to this comparative example, control is not performed so that the loop formed on the paper P is eliminated when the rear end portion of the paper P passes through the nip portion N2. . For this reason, as shown in FIG. 10A, when the rear end portion of the paper P passes through the nip portion N2, there may occur a situation where the loop has not yet been eliminated.

  In this case, the rear end portion of the sheet P that has passed through the nip portion N2 is not separated from the second driven roller 730 and is attracted to the second driven roller 730. As the second driven roller 730 rotates, for example, FIG. There is a possibility that the rear end of the paper P moves to the position indicated by the solid line in FIG. When the trailing end of the sheet P is separated from the second driven roller 730 at the position indicated by the solid line in FIG. 10A, the sheet P is, for example, illustrated in FIG. ) To the position indicated by the two-dot chain line, and then to the position indicated by the solid line in FIG. Then, when the paper P moves to the position indicated by the solid line in FIG. 10B, the rear end portion of the paper P collides with the second driven roller 730, and a sound is generated at the time of the collision.

  FIG. 11 is a second view for explaining the state of the paper P in the image forming apparatus according to the comparative example of the present invention. FIG. 11A shows a state when the rear end portion of the paper P passes through the nip portion N2. The state of the paper P is shown, and FIG. 11B shows the state of the paper P after a certain time has elapsed from the time shown in FIG.

  In the image forming apparatus 10 according to this comparative example, the rear end portion of the paper P that has passed through the nip portion N2 is not separated from the second driven roller 730 and is attracted to the second driven roller 730, and the second driven roller With the rotation of 730, for example, the rear end of the paper P may move to the position indicated by the solid line in FIG.

  When the suction between the second driven roller 730 and the rear end of the paper P is released by the rigidity of the paper P (the stiffness of the paper P) at the position indicated by the solid line in FIG. Thus, the sheet P moves so as to slide on the surface of the second driven roller 730 from, for example, a position indicated by a two-dot chain line in FIG. 11B to a position indicated by a solid line in FIG. When the paper P moves to the position indicated by the solid line in FIG. 11B, the rear end portion of the paper P collides with the supply roller 710, and a sound is generated at the time of the collision.

  FIG. 12 is a third diagram for explaining the state of the paper P in the image forming apparatus according to the comparative example of the present invention. FIG. 12A shows the state immediately before the trailing edge of the paper P passes through the nip portion N2. The state of the paper P at the time is shown, and FIG. 12B shows the state of the paper P immediately after the rear end of the paper P passes through the nip portion N2.

  In the image forming apparatus according to this comparative example, the loop of the paper P is eliminated before the rear end portion of the paper P passes through the nip portion N2, and the rear end of the paper P passes through the nip portion N2. At this time, as shown in FIG. 12A, the sheet P may be pulled between the nip portion N2 and the nip portion N1 in the transport direction front side and the transport direction rear side.

  In this case, when the loop is canceled before the rear end portion of the paper P passes through the nip portion N2, the paper P is pulled, and a so-called loop canceling sound is generated when the paper P is pulled. Here, it seems that the above-described loop canceling sound can be canceled by providing a one-way clutch on the second driven roller 730, for example. However, since the second driven roller 730 has inertia, even if a one-way clutch is provided on the second driven roller 730, the paper P may be pulled when the loop is eliminated. There is a possibility that sound is generated by being pulled.

  As described above, the present invention can be used for an image forming apparatus such as a copying machine, a facsimile apparatus, and a printer, and for example, a conveyance device used in these image forming apparatuses.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 12 ... Image forming apparatus main body 20 ... Controller 30 ... Operation panel 100 ... Image forming part 410 ... Container sensor 640 ... Paper sensor 700 ... Resist Roller 710 ... Supply roller 720 ... First driven roller 730 ... Second driven roller 740 ... Motor 742 ... Drive transmission mechanism 810 ... First nip pressure adjusting mechanism 820 ... First 2 Nip pressure adjustment mechanism 822 ... Motor 824 ... Cam mechanism

Claims (6)

A transport member for transporting a transport object;
A supply member that is disposed upstream of the transport member in the transport direction of the transport object and that supplies the transport object toward the transport member;
The conveyance member conveys the conveyance object so that the bending formed in the conveyance object between the supply member and the conveyance member is eliminated when the rear end of the conveyance object passes through the supply member. Adjusting means for adjusting at least one of a speed to perform and a speed at which the supply member supplies the conveyance object;
Conveying device having At least one of a first contact member disposed so as to sandwich a conveyance object between the conveyance member and a second contact member disposed so as to sandwich a conveyance object between the supply member. One of them,
2. The transport according to claim 1, wherein the adjusting unit adjusts at least one of a force by which the first contact member and the transport member are pressed and a force by which the second contact member and the supply member are pressed. apparatus.   The said adjustment means adjusts at least any one of the speed at which the said conveyance member conveys a conveyance object, and the speed at which the said supply member supplies a conveyance object according to the thickness of a conveyance object. The conveying apparatus as described.   The adjusting means is at least one of a speed at which the transport member transports the transport target object and a speed at which the supply member supplies the transport target object according to the length of the transport target object in the direction in which the transport target object is transported. The conveying apparatus according to any one of claims 1 to 3, wherein one side is adjusted.   The adjusting means adjusts at least one of a speed at which the transport member transports the transport target object and a speed at which the supply member supplies the transport target object according to the number of transport target objects transported. The conveying apparatus in any one of thru | or 4. An image forming unit for forming an image on a recording medium;
A transport member that transports a transport target toward the image forming unit;
A supply member that is disposed upstream of the transport member in the transport direction of the recording medium and that supplies the recording medium toward the transport member;
A speed at which the conveying member conveys the recording medium so that the bending formed in the recording medium between the supply member and the conveying member is eliminated when the trailing edge of the recording medium passes through the supplying member; Adjusting means for adjusting at least one of the speeds at which the supply member supplies the recording medium;
An image forming apparatus.

Images