JP6248541B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that detects the occurrence of winding of a recording medium.

  In an electrophotographic image forming apparatus, it is necessary to detect a paper jam that occurs when a paper is passed through, stop the operation of the device, and remove the paper jam. At this time, as a means for detecting a paper jam at the position of the pair of transport rollers, there is a method of using a conductive material for the transport rollers.

  However, because of the friction coefficient, a rubber transport roller is usually used, so a structure using rubber added with a conductive material is used, and the paper sandwiched between the transport roller pair is not detected. Means for providing a sensor in the vicinity of the roller to detect the presence or absence of paper is already known.

  In Patent Document 1, for the purpose of directly detecting a sheet on a pair of conveyance rollers, a roller member having a conductive surface, a power supply member in contact with the surface of the roller member, and a voltage is applied to the power supply member. A power supply unit; a sheet separation unit made of a conductive member that is in contact with the surface of the roller member and disposed in a sheet passing area of the roller member; and a voltage detection unit that detects a voltage of the sheet separation unit. A detection device is disclosed.

  In Patent Document 2, a predetermined bias voltage is applied between two conductive sheet conveying members provided along the sheet conveying direction in the sheet conveying path, and a resistance value between these sheet conveying members is set. A sheet edge detection method for detecting an edge of a sheet conveyed through a sheet conveyance path by measurement is disclosed.

  When two sheet conveying members provided along the sheet conveying direction are made conductive and a bias voltage is applied between these sheet conveying members, the sheet is conveyed in a state straddling the two sheet conveying members. Current flows through the sheet only during the period. On the other hand, in a state other than this, that is, a state where the sheet has not reached any of the two sheet conveying members, and a state where the sheet has reached only one of the two sheet conveying members, Since there is no connection between the sheet conveying members, no current flows.

  However, in conventional electrophotographic image forming apparatuses, when detecting a paper jam that occurs when a paper is passed, the material of the transport roller is used as a means for detecting a paper jam at the position of the pair of transport rollers. Although there is a method of using a conductive material, since a rubber conveyance roller is usually used because of a friction coefficient, rubber with a conductive material is expensive.

  Further, in the means for detecting the presence or absence of paper by providing a sensor in the vicinity of the conveying roller disclosed in Patent Document 1, when an operator unfamiliar with the operation of the image forming apparatus removes jammed paper, it is installed in the device. Pulling the paper sandwiched between the transport roller pair and providing a piece of paper remaining on the roller pair near the transport roller without noticing the presence of a knob that manually rotates the roller and a release lever for providing a gap between the roller pair There has been a problem that the sensor remains in a place where it cannot be detected.

  In the technique disclosed in Patent Document 2, it is necessary to select a material having a friction coefficient sufficient to convey a sheet and having conductivity as a material of the conveying member. Two or two of the conveying members are made of rubber, and the rubber has no conductivity. When this is made conductive, there is a rubber in which conductive materials are mixed. However, the rubber having conductivity compared with the rubber having no conductivity is a special one, and the problem of high cost for it is not solved.

  The present invention is for solving the above-mentioned problems, and the object of the present invention is as a means for detecting a paper jam at the position of the pair of transport rollers while transporting the material of the transport rollers made of non-conductive rubber. An object of the present invention is to provide an image forming apparatus capable of detecting a sheet sandwiched between a pair of rollers on a conveying roller.

  In order to achieve this object, the present invention has the following features.

The image forming apparatus according to the present invention is an image forming apparatus having a conveying roller in which the position of a conveying roller pair for driving and conveying a sheet is vertically arranged, and a non-conductive upper side constituting the conveying roller pair A conductive circular plate attached to a drive shaft of the lower roller, a roller and a lower roller, and a conductive ring movably provided within a range in which the drive shaft of the upper roller enters the inside of the ring and Jo plate, attached to the drive shaft of the upper roller, the ring-shaped plate, said at conveying roller pair stopped in contact with the circular plate, the circular plate at the time of the conveyance roller pair rotates A moving means for moving them in a non-contact manner, a mechanism that uses the rotational driving force of the transport roller, and an electronic control device that detects contact and non-contact between the ring-shaped plate and the circular plate, , have a, The electronic control device detects that the ring-shaped plate and the circular plate are not in contact with each other, so that no current flows through the ring-shaped plate when the pair of conveying rollers stops, and the upper roller and the lower roller are detected. The presence of the sheet between the side rollers is detected .

  According to the present invention, as means for detecting a paper jam at the position of the transport roller pair, the paper sandwiched between the transport roller pair can be detected on the transport roller while the material of the transport roller is made of non-conductive rubber. it can.

1 is a schematic diagram illustrating an overall configuration of a stencil printing apparatus according to the present embodiment. It is a front view of the conveyance roller pair which concerns on this embodiment. It is a side view of the conveyance roller pair which concerns on this embodiment. It is a figure which shows that a conveyance roller rotates in a paper passing direction. FIG. 6 is a diagram illustrating a case where a paper jam occurs on a conveyance roller. FIG. 6 is a diagram illustrating a state where a sheet sandwiched between a pair of conveyance rollers is torn.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an overall configuration of a stencil printing apparatus 1 according to the present embodiment. An outline of the overall configuration of the stencil printing apparatus 1 will be described with reference to FIG.
A pair of conveying rollers is provided in all image forming apparatuses, but some of them may need to be made of rubber (elastic body) with conductivity added for reasons such as toner fixation. A mechanism of a stencil printing apparatus having a conveyance roller that does not need to be rubber (elastic body) will be described.

  The printing unit 2 is provided in the center of the printing apparatus main body, and the printing unit 2 includes a plate cylinder 10, a clamper 10a, a support shaft 11, an ink supply unit 12, a printing pressure roller 16, and the like. The plate cylinder 10 is composed of a porous cylindrical metal thin plate and a mesh screen wound around the outer periphery thereof, and has a clamper 10a for locking the leading end of the stencil sheet at a part of the outer periphery.

  The plate cylinder 10 is rotatably supported by a support shaft 11 that also serves as an ink supply pipe, and is driven to rotate in the direction of the arrow by a driving means (not shown). Inside the plate cylinder 10, an ink supply means 12 including an ink roller 13 and a doctor roller 14 is disposed. The ink supplied from the support shaft 11 forms an ink reservoir 15 in the vicinity of the ink roller 13 and the doctor roller 14, and the ink in the ink reservoir 15 passes through the proximity of the ink roller 13 and the doctor roller 14 to form the ink. A layer is supplied to the peripheral surface of the roller 13.

  The printing roller 16 is controlled by a printing pressure driving means (not shown) in time with a predetermined area of the plate cylinder 10 so that the ink roller 13 contacts the inner peripheral surface of the plate cylinder 10. As a result, ink is supplied to the inner peripheral surface of the plate cylinder 10 and oozes out from the opening of the plate cylinder 10 and is transferred onto the paper.

  A plate making unit 3 is provided on the upper right side of the printing unit 2, and the plate making unit P3 includes a stencil sheet roll 20, a platen roller 22, a thermal head 23, a cutter 24, a plate feed roller pair 25, and the like. The stencil sheet 21 of the rolled stencil sheet roll 20 is pressed against the thermal head 23 by the platen roller 22 to be heated and perforated, and is fed and conveyed toward the outer peripheral surface of the plate cylinder 10 by the pair of feed rollers 25. The plate-making stencil sheet is wound around the outer periphery of the plate cylinder 10 by the tip of the clamper 10a being clamped, and is cut by a cutter 24 to the length of one plate.

  A sheet feeding unit 4 is provided below the plate making unit 3, and the sheet feeding unit 4 includes a sheet feeding tray 30, a sheet feeding roller 31, a separation roller 32, a separation pad 33, a registration roller pair 34, and the like. The paper feed tray 30 is attached to the inside of the casing side plate (not shown) so as to be movable in the vertical direction perpendicular to the paper transport direction, and a pair of side fences 35 for aligning the paper P in the width direction are synchronized with each other. It is configured to be movable.

  Above the paper feed tray 30, paper feed rollers 31 and 32 having high frictional resistance members on their respective surfaces are arranged and driven to rotate by a driving means (not shown). When the paper feed tray 30 is raised, the paper P is pressed against the paper P with a predetermined pressure by the paper feed roller 31, and the paper is separated one by one by the separation roller 32 and the separation pad 33 and conveyed to the registration roller pair 34.

  The registration roller pair 34 is rotationally driven at a predetermined timing by driving force means (not shown), and conveys the sheet between the plate cylinder 10 and the printing pressure roller 16. A plate discharging unit 5 is provided on the upper left side of the printing unit 2. The plate discharge box 41 includes a compression plate 44 that compresses a used master 43 conveyed into the plate discharge box 41 by a plate discharge roller pair 42, and a compression plate 44 that is substantially orthogonal to the master discharge path. A support shaft 44a that supports the end portion and rotates the compression plate 44 within the plate discharging box 41 is provided.

  By rotating the compression plate 44 at least 90 ° or more about the support shaft 44a as a rotation center, the used master 43 conveyed into the plate discharging box 41 is compressed and accommodated in the plate discharging box 41. .

  A paper discharge unit 6 is provided below the plate discharge unit 5, and the paper discharge unit 6 includes a peeling claw 50, a paper discharge transport unit 51, a paper discharge storage unit 52, and the like. The printed paper is peeled from the outer peripheral surface of the plate cylinder 10 by the peeling claw 50. The peeling claw 50 is swingably supported on the side plate of the printing apparatus main body by a support shaft, and is moved by the rotation of the plate cylinder 10 at a position where the tip thereof is close to the outer peripheral surface of the plate cylinder 10 by a swing means (not shown). Is selectively swung to a position where it does not interfere with the clamper 10a and the like.

  The paper discharge conveyance unit 51 includes a driving roller 53, a driven roller 54, an endless belt 55, and a suction fan 56. The driving roller 53 and the driven roller 54 are rotatably supported by a unit side plate (not shown), and the driving roller 53 is rotationally driven by a driving means (not shown). An endless belt 55 having a plurality of apertures is stretched between the driving roller 53 and the driven roller 54. The driving roller 53 is driven by the driving means, and the printed paper is fed by the suction fan 56 below the endless belt. The sheet is conveyed to the paper discharge storage unit 52 while being sucked upward.

  The paper discharge storage unit 52 includes a paper discharge tray 57 on which printed paper conveyed by the paper discharge conveyance unit 51 is stacked, a side fence 58 for aligning printed paper, and a pair of end fences 59. . The side fence 58 is configured to be movable toward and away from the sheet width direction, and the end fence 59 is configured to be movable in the sheet conveyance direction.

  An operation panel and an image reading unit 7 are provided on the upper part of the casing constituting the exterior of the stencil printing apparatus 1. The image reading unit 7 includes a contact glass 60 on which a document is placed, a pressure plate 61 provided so as to be able to come in contact with and away from the contact glass 60, reflection mirrors 62, 63, 64, 65 for scanning and reading a document image, and fluorescence. A lamp 66, a converging lens 67 for converging the scanned image, an image sensor 68 such as a CCD for processing the converging image, a plurality of document size detection sensors 69 for detecting the size of the document, and the read image And an image memory 70 for storing data.

  Next, the configuration of the conveying roller pair will be described by taking the registration roller pair 34 as an example. FIG. 2 is a front view of the conveying roller pair according to the present embodiment. FIG. 3 is a side view of the conveying roller pair according to the present embodiment.

  The conveying roller pair includes a roller 101 and a roller 102, and the roller 101 and the roller 102 are elastic bodies having no conductivity, and are made of rubber in this embodiment. Depending on the transport conditions, a non-conductive material such as resin may be used, and the material is not limited to an elastic body.

  As shown in FIG. 2, the mechanism 100 according to the present embodiment is disposed at both ends of the roller 101, but the mechanism 100 a and the mechanism 100 b according to the present embodiment are symmetrical with respect to the roller 101. This will be described with reference to 100a.

  The roller 101 is disposed on the drive shaft 103 and the roller 102 is disposed on the drive shaft 104. In FIG. 3, the roller 101 and the roller 102 are stopped. The circumference of the metal plate 105 in the form of a ring is a circular metal plate arranged coaxially with the drive shaft 104 while the inner side of the ring enters the drive shaft 103 and is held by the shaft 106 inserted into the drive shaft 103. It is in contact with the circumference of 107.

  The specific metal material of the circular metal plate 107 is not particularly limited because it is conductive if it is a metal, but generally speaking, from the viewpoint of being inexpensive and commercially available in the market, Aluminum is used.

  The metal plate 105 is connected to the conductive line 125, the metal plate 107 is connected to the conductive line 126, and when the metal plate 105 and the metal plate 107 are in contact with each other, the electronic control unit 127 is turned on. While the rollers 101 and 102 are stopped, it is detected that there is no transport paper between the metal plate 105 and the metal plate 107 and there is no paper between the roller 101 and the roller 102, and it is determined that there is no paper jam. The metal plate 105 and the shaft 106 are prevented from falling off the shaft 106 by holding plates 121 and 122 held by the shaft 106.

  FIG. 4 is a diagram illustrating that the conveyance roller rotates in the sheet passing direction. The drive shaft 103 rotates and the shaft 106 also rotates together. The shaft 106 has a function of a torque limiter. The torque limiter is known and will not be described.

  A projection 108 is provided on the shaft 106, and the projection 108 hits the stopper 109. When a predetermined torque is reached, the shaft 106 idles and the projection 108 maintains the state shown in FIG. The inside of the metal plate 105 is held by the protrusion 108 and moves from the position of FIG. 3 to the position of FIG. 4 in accordance with the rotation of the protrusion 108. The sheet 110 passes through the roller 101 and the roller 102.

  Next, a case where a paper jam occurs on the transport roller will be described. FIG. 5 is a diagram illustrating a case where a paper jam has occurred in the transport roller. When a paper jam occurs on the transport roller, current does not flow through the metal plate 105 and the metal plate 107, and the transport roller stops.

  As described with reference to FIG. 4, the shaft 106 has the function of a torque limiter and at the same time the function of a one-way clutch. The one-way clutch is known and will not be described.

  The shaft 106 is rotated to the position shown in FIG. The protrusion 108 does not hold the metal plate 105. The metal plate 105 falls down and hits the jammed paper 111 and stops. Since the metal plate 105 and the metal plate 107 are not in contact with the roller 101 and the roller 102 being stopped, it is detected that there is a sheet between the roller 101 and the roller 102 and it is determined that there is a paper jam.

  FIG. 6 is a diagram illustrating a state where the sheet sandwiched between the pair of transport rollers is torn. Even if the sheet sandwiched between the conveyance roller pair is forcibly pulled and broken, even a small piece 112 of the sheet can be detected. A piece of paper 112 remaining between the conveyance rollers occurs at a portion sandwiched between the conveyance rollers. Therefore, if the mechanisms 100a and 100b of this embodiment are arranged at both ends of the conveyance roller, the piece of paper 112 can be detected. Is possible.

  There is no upper limit on the number of rollers 101 arranged on the drive shaft 103. Considering that the position where the cut edge 112 of the paper is generated increases depending on the size of the paper to be passed, the number of places where it is desired to detect the residual paper between the transport rollers is increased. If desired, the number of rollers may be increased. With regard to the configuration of the roller 102 and the metal plate 107, the roller 102 may be made of metal and the metal plate 107 may be removed depending on the conveyance conditions.

  Although the recording sheet to be conveyed is described as a sheet as an embodiment, the material of the sheet is not limited to paper and may be non-conductive. In the present embodiment, the positional relationship between the pair of transport rollers is a position where the center of rotation of the roller pair is vertical, but may not be vertical as long as the mechanism of the present embodiment can be maintained.

  The remaining jammed paper detected by this mechanism is displayed on the operation unit of the main body of the apparatus. However, a light emitting means and an audio output means (not shown) are provided in the vicinity of the conveying roller, and the jamming sheet having the mechanism of the present embodiment is provided. Before closing the open / close cover, the operator may be notified of the presence or absence of jammed paper.

  According to the present embodiment, a ring-shaped metal is provided on the same axis as the pair of conveyance rubber rollers, so that the rotation of the rubber roller during conveyance of the paper does not contact the pair of ring-shaped metals, and the pair of ring-shaped metals when stopped. Since the metal contacts, as a means of detecting paper jam at the location of the transport roller pair, the paper sandwiched between the transport roller pair can be detected on the transport roller while the material of the transport roller is made of non-conductive rubber. it can.

  The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. is there.

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 34 Registration roller pair 100 Mechanism 101 Roller 103 Drive shaft 105 Metal plate 106 Shaft 108 Protrusion 109 Stopper 110 Paper 111 Jam paper 112 Paper piece

JP2003-081523A Japanese Patent No. 3980393

Claims (6)

An image forming apparatus having conveyance rollers in which the positions of a conveyance roller pair that drives and conveys a sheet are arranged above and below,
A non-conductive upper roller and a lower roller constituting the conveying roller pair;
A conductive circular plate attached to the drive shaft of the lower roller;
A conductive ring-shaped plate provided movably within a range in which the drive shaft of the upper roller enters the inside of the ring ;
The ring-shaped plate attached to the drive shaft of the upper roller is brought into contact with the circular plate when the conveying roller pair is stopped, and is not in contact with the circular plate when the conveying roller pair is rotated . moving means for moving so,
A mechanism that uses the rotational driving force of the transport roller;
Have a, and an electronic control unit for detecting contact and non-contact and with the ring-shaped plate and the circular plate,
The electronic control unit detects that the ring-shaped plate and the circular plate are not in contact with each other, so that no current flows through the ring-shaped plate when the pair of conveying rollers is stopped, and the upper roller and the lower roller are detected. An image forming apparatus that detects the presence of the sheet between the side rollers . The moving means is
A protrusion for moving the ring-shaped plate upward from the circular plate to a non-contact position ;
The projection is provided, the image forming apparatus according to claim 1, wherein a, a shaft that rotates in accordance with the said drive shaft of said upper roller. The moving means is
The image forming apparatus according to claim 2, further comprising a stopper that contacts a tip of the protrusion at a position facing upward. It said shaft which rotates in conjunction with the drive shaft of the upper roller, when the tip of the protrusion is in contact with the stopper, the image forming apparatus according to claim 3, wherein the blocking torque transmission. Shaft that rotates in accordance with the said drive shaft of the upper roller, wherein when the drive shaft is stopped the upper roller, projecting Kiga by the weight of the projection to the ring-shaped plate is in contact with said circular plate The image forming apparatus according to claim 2, wherein the image forming apparatus idles in a direction facing downward.   The roller width of the conveying roller pair is narrower than the width of the sheet.
  The circular plate is provided on both sides of the lower roller in the sheet width direction,
  6. The image forming apparatus according to claim 1, wherein the ring-shaped plate and the moving unit are provided on both sides of the upper roller in the sheet width direction.

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