JP2014024637A - Paper jam detection device and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper jam detection device in which paper jam is less likely to occur even if a thin recording medium is used, without increasing the size of the device, and to provide an image forming apparatus.SOLUTION: A paper jam detection device and an image forming apparatus comprise: a first conveyance guide 5 arranged in a medium conveyance path 7 of a medium 2; a second conveyance guide 6 arranged opposite to the first conveyance guide across the medium conveyance path; a medium conveying part which conveys a medium; a recess 15 which is provided to the second conveyance guide and is oriented perpendicular to the direction of medium conveyance; a sensor 16 which is arranged in the recess and detects a medium which has entered the recess; and a movable piece 18 which goes into and out of the recess and the medium conveyance path.

Description

  Embodiments described herein relate generally to a paper jam detection device and an image forming apparatus using the paper jam detection device.

  In a conveyance device that conveys a medium such as paper, a paper jam may occur in the middle of conveyance. When a paper jam occurs, the device including the transport device does not operate normally. For example, when a paper jam occurs, an image forming apparatus such as a printer needs to quickly detect the paper jam and notify a repair person.

  In a printer installed in an automatic teller machine such as a bank, a customer may block a recording medium discharge port by hand, and the recording medium may be jammed in a conveyance path, and a paper jam may occur.

  Conventionally, since the recording medium used in a printer is sufficiently thick, the conveyance force of the recording medium is kept low so that the recording medium is not bent and clogged in a portion where the recording medium conveyance path is narrow. . However, in recent years, the thickness of recording media used for printers is becoming thinner for the purpose of environmental measures and the like. For this reason, even if the conveyance force of the recording medium is kept low, the sheet is easily bent and jammed in a portion where the recording medium conveyance path is narrow.

  In this regard, when the recording medium is not discharged from the recording medium discharge port, a paper receiving means for storing the recording medium to be conveyed is provided, and a transmission type sensor that is shielded by the recording medium is provided in the paper receiving means. A technique for determining a paper jam based on the output of a sensor has been proposed.

Japanese Patent Laid-Open No. 11-21001

  However, according to this technology, the apparatus becomes larger by providing the sheet receiving means, and the manufacturing cost is increased.

  It is also conceivable to provide a sensor for detecting a recording medium that has entered a concave portion provided in a direction perpendicular to the recording medium conveyance direction in a part of the opposed medium conveyance guide. In this case, since the receiving unit is not provided, it is possible to avoid an increase in the size of the apparatus. However, there is a possibility that the leading end of the thin recording medium is clogged by bending the sheet into the recess.

  Accordingly, there is a need for a paper jam detection device and an image forming apparatus that do not cause paper jams even on thin recording media without increasing the size of the device.

  One embodiment of the present invention includes a first conveyance guide disposed in a recording medium conveyance path of a recording medium, and a second conveyance guide disposed opposite to the first conveyance guide across the recording medium conveyance path. A concave portion provided in a direction perpendicular to the recording medium conveyance direction and the inside of the concave portion in the recording medium conveyance unit for conveying the recording medium, the image forming unit for forming an image on the recording medium, and the first recording conveyance guide. An image forming apparatus is provided that includes a sensor that detects a recording medium that has entered the recess, and a movable piece that advances and retreats in the recess and in the medium transport path.

It is a side view of an image forming apparatus including a jam detection device. 1 is a block diagram including a configuration of an image forming apparatus. It is a principal part block diagram of a jam detection apparatus. It is a downward perspective view of the principal part of a jam detection apparatus. It is a perspective view near the recessed part of the 2nd conveyance guide. It is a side view near the recessed part of the 2nd conveyance guide. It is the figure which showed the curled recording medium and movable piece in a jam detection apparatus. It is the figure which showed the state which blocked the discharge port in a jam detection apparatus. FIG. 6 is a diagram illustrating a state where the recording medium is conveyed after the discharge port in the jam detection device is blocked. It is a figure when the obstruction | occlusion of the discharge port in a jam detection apparatus is removed. It is the figure which showed the position of the 2nd conveyance guide and a movable piece. It is the upper surface which showed the position of several medium and a movable piece.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a side view of an image forming apparatus 1 including a paper jam detection device according to the present embodiment. In the image forming apparatus 1, the recording medium 2 is conveyed from the left side to the right side in the figure. Therefore, in the following description, the left side in the figure is the upstream side and the right side is the downstream side. In the figure, reference numeral 2 denotes roll paper wound around the winding shaft 3, and the winding shaft 3 is rotatably supported by the image forming apparatus 1. An idler roller 4 is rotatably supported on the downstream side of the recording medium 2.

  Further, the image forming apparatus is provided with a first conveyance guide 5 that is a conveyance guide for the recording medium 2, and a second conveyance guide 6 with the first conveyance guide 5 and the sheet conveyance path 7 interposed therebetween.

  Further, a platen roller 9 that can be rotated by a motor (not shown) and a thermal print head 8 that is disposed opposite to the platen roller 9 with the paper transport path 7 interposed therebetween are disposed in the paper transport path 7. The platen roller 9 and the thermal printing head 8 constitute a printing mechanism 19. The thermal print head 8 prints line by line in accordance with the conveyance of the recording medium 2 when the recording medium 2 is conveyed downstream on the paper conveyance path 7. The thermal print head 8 is pressed by the platen roller 9 so that the recording medium 2 is sent to the downstream side by friction between the thermal print head 8 and the platen roller 9. That is, the thermal head 8 and the platen roller 9 constitute an image forming unit and a recording medium conveying unit.

  The cutter 10 is disposed downstream of the printing mechanism 19 in the printing conveyance direction. The image forming apparatus 1 cuts the recording medium 2 inserted in a slit (not shown) provided in the cutter 10.

  The recording medium 2 cut by the cutter 10 is discharged out of the image forming apparatus 1 through a discharge port 13 provided on the most downstream side of the sheet conveyance path 7.

  The paper transport path 7 is provided with a transport roller 11 that can be rotated by a motor (not shown), and an idler roller 12 that faces the transport roller 11 with the paper transport path 7 interposed therebetween. The recording medium 2 is sent to the downstream side by sandwiching the transport roller 11 and idler roller 12. That is, the transport roller 11 and idler roller 12 constitute a recording medium transport unit. Note that there is no problem whether the transport roller 11 and the idler roller 12 are provided as a pair or a plurality of pairs on the paper transport path 7.

  Further, the second transport guide 6 is provided with a recess 15 in the vicinity of the discharge port 13 in a direction perpendicular to the transport direction of the recording medium 2, and a reflective sensor 16 is provided inside the recess 15. .

  Of the pair of transport roller 11 and idler roller 12, a movable piece centered on the shaft 17 of the transport roller 11 in the pair of transport roller 11 and idler roller 12 provided on the most downstream side in the transport direction of the recording medium 2. 18 is provided. Here, the shaft 17 of the conveyance roller 11 at the most downstream side in the conveyance direction of the recording medium 2 in the pair of the conveyance roller 11 and the idler roller 12 is set as the rotation center, but it is not necessarily at the most downstream side but near the concave portion 15. That's fine. Further, although the shaft 17 of the transport roller 11 is the center of rotation, the shaft (not shown) of the idler roller 12 may be the center of rotation.

  FIG. 2 shows the control unit 50 of the image forming apparatus 1 described above. The control unit 50 includes means for controlling each of paper conveyance, printing, paper cutting, paper jam detection, and display.

  When data to be printed is sent from the host computer 61 to the image forming apparatus 1, the control unit 50 in the image forming apparatus 1 links with the host computer 61 and executes various controls. It is configured. A central processing unit (MPU) 51 of the control unit 50 performs various controls and operations such as paper conveyance control, printing control, paper cutting control, paper jam detection, and display according to a program. The MPU 51 also includes a timer 52 as means for performing time setting and time control.

  A ROM 53 and a RAM 54 are installed as main storage means for storing a control program executed by the MPU 51 and data during control or calculation. The ROM 53 is a read-only memory having a control program, a table, and the like, and the RAM 54 is an occasional write memory for storing data in the middle of calculation.

  Further, the control unit 50 is provided with an input / output unit (I / O) 55 for taking in various input data from the host computer 61 and taking out the control output of the control unit 50 to the host computer 61. Yes. The I / O 55 is linked to the MPU 51, the ROM 53, and the RAM 54 through a bus.

  The I / O 55 is connected with first, second, third, fourth and fifth drivers 56, 57, 58, 59 and 60 as means for taking out the control output. The driver 56 supplies necessary drive output to the printing mechanism 19. The driver 57 supplies a necessary drive output to the transport roller 11. The driver 58 supplies the necessary drive output to the cutter 10. The driver 59 supplies a necessary drive output to the sensor 16. The driver 60 supplies a display drive output that causes the display unit 20 to perform various displays.

  The printing mechanism 19 includes the thermal print head 8 and the platen roller 9 described with reference to FIG. The platen roller 9 is driven to rotate in synchronization with a printing operation by a motor (not shown) based on a control output as a printing command means of the MPU 51. The thermal print head 8 prints on the recording medium 2 based on print data from the host computer 61.

  The MPU 51 of the control unit 50 rotates and stops the transport roller 23 via the driver 57.

  Further, the MPU 51 of the control unit 50 drives the cutter 10 via the driver 58 to cut the recording medium 2.

  Further, the MPU 51 of the control unit 50 drives the sensor 16 via the driver 59 to detect the presence / absence of the recording medium 2.

  Further, the MPU 51 of the control unit 50 displays various states of the image forming apparatus 1, error contents, and the like on the display unit 20 via the driver 60.

  Hereinafter, the operation of the image forming apparatus 1 will be described with reference to FIGS. 1 and 3 to 10.

  The recording medium 2 wound around the winding shaft 3 is wound around the idler roller 12 and then conveyed toward the downstream side through the sheet conveyance path 7 between the first conveyance guide 5 and the second conveyance guide 6. . In the conveyance, the idler roller 12 and the idler roller 12 are conveyed in cooperation with the conveyance roller 11 disposed so as to face the idler roller 12 with the sheet conveyance path 7 interposed therebetween.

  A thermal print head 8 is provided in the paper conveyance path 7 of the image forming apparatus 1, and print data sent from the host computer 61 is printed on the print surface 14 on which the heat sensitive layer of the recording medium 2 is provided. I do. A platen roller 9 is disposed opposite the thermal printing head 8 with the paper conveyance path 7 interposed therebetween, and the recording medium 2 is also conveyed by friction between the thermal printing head 8 and the platen roller 9.

  A cutter 10 is provided on the downstream side of the thermal print head 8 in the transport direction, and the printed recording medium 2 is inserted into a slit (not shown) provided in the cutter 10 and is subsequently transported downstream in the transport direction. The

  Thereafter, the recording medium 2 continues to be transported downstream in the transport direction, and eventually the leading end of the recording medium 2 reaches the recess 15 provided in the second transport guide 6.

  As shown in FIG. 3, the recess 15 provided in the second transport guide 6 includes a sensor 16 that detects the recording medium 2 that has entered the recess 15, and the recess 15 and the sheet transport path 7. A movable piece 18 that advances and retreats is provided, and the movable piece 18 is provided on the most downstream side in the conveyance direction of the recording medium 2 in the pair of the conveyance roller 11 and the idler roller 12. The shaft 17 of the conveyance roller 11 in the pair is provided with the rotation center.

  Note that it is desirable that the rotation center be provided on the upstream side in the medium conveyance direction with respect to the recess 15 because it is difficult to cause a conveyance load when the recording medium 2 abuts.

  The sensor 16 provided in the recessed part 15 is demonstrated in detail using FIG. 5 and FIG. The sensor 16 includes a light emitting element 16a and a light receiving element 16b. The light emitting element 16a emits light toward the recording medium 2 that has entered the recess 15, and the light receiving element 16b is reflected by the recording medium 2 that has entered the recess 15. Receive the received light. The depth D1 of the recess 15 is set deeper than the length of the sensor 22 that can detect the reflected light. With this setting, the sensor 16 detects the recording medium 2 passing above the extended surface X (see FIG. 3) of the second conveyance guide 6 excluding the recess 15 (see FIG. 3). Absent.

  As shown in FIG. 4, the movable piece 18 is provided at the center of rotation below the X plane. The movable piece 18 passes through the slit 24 provided in the recess 15 and is provided from below to the recess 15. ing. One end of a lever spring 22 is attached to the movable piece 18, and the other end of the lever spring 22 is attached to a spring shaft 23 fixed to a frame (not shown) of the image forming apparatus 1. . As shown in FIG. 3, the lever spring 22 applies a rotational force to the movable piece 18 in the Y direction (see FIG. 1) with the shaft 17 as the center of rotation. At this time, the upstream end portion of the slit 24 in the conveying direction and the movable piece 18 are in contact with each other to regulate the tip position of the movable piece 18. At this time, the tip portion 21 of the movable piece 18 is substantially the same as the extension surface X. It is set to be high.

  Further, as shown in FIG. 11, even if the conveyance surface X of the second conveyance guide 6 and the upper surface F of the movable piece 18 are set to have substantially the same height, the conveyance during the conveyance is not adversely affected.

  FIG. 6 shows a state where the recording medium 2 in the winding direction shown in FIG. 1 has been conveyed to the recess 15. A recording medium 2 having a curl as shown in FIG. 7 is conveyed, but the front end of the recording medium 2 is not moved into the concave portion 15 by the movable piece 18 that has advanced with respect to the concave portion 15 and is directly downstream. Then, the sheet is cut to a required length by the cutter 10 and discharged from the discharge port 13 to the outside of the image forming apparatus 1. At this time, the lever spring 22 is set to have such a strength that the movable piece 18 does not rotate in the Z direction (see FIG. 1) due to the frictional force during conveyance between the recording medium 2 and the movable piece 18 (A condition).

  Further, as shown in FIG. 11, when the width H on the rotation center side and the width I on the front end side of the movable piece 18 are compared, it is desirable that H> I. Thereby, it becomes possible to rotate with a weak spring compared to H <I or the like.

  FIG. 8 shows a state in which the discharge port 13 is blocked by an obstacle 25 such as a human hand and the conveyance of the recording medium 2 is hindered. This state is an initial state of paper jam. Thus, even when the discharge port 13 is blocked by an obstacle 25 such as a human hand, the sensor 16 still does not detect the recording medium 2. Therefore, the recording medium transport unit continues to transport the recording medium 2 downstream in the transport direction. At this time, the strength of the lever spring 22 depends on the conveyance of the recording medium 2 by the cooperation of the conveyance roller 11 and the idler roller 12 or the cooperation of the thermal print head 8 and the platen roller 9 with the discharge port 13 being blocked. The movable piece 18 is strong enough to retract from the concave portion 15 so as not to prevent the recording medium 2 from following the shape of the concave portion 15 during conveyance of the recording medium 2 (condition B). That is, the lever spring 22 is set to satisfy both the A condition and the B condition.

  For this reason, the recording medium 2 follows the shape of the recess 15 as shown in FIG. 9, but in the process, the sensor 16 detects the recording medium 2 and outputs a signal to the control unit 50 that a paper jam has occurred. When recognizing this paper jam signal, the control unit 50 stops the drive of the recording medium transport unit via the driver 56 and driver 57 and clearly indicates the paper jam on the display unit 20 via the driver 60.

  Here, when the sensor 16 outputs a paper jam signal, a timer 52 provided in the MPU 51 starts. When the recording medium 2 is jammed, the movable piece 18 rotates in the Y direction as shown in FIG. 10 by removing the obstacle 25 such as the hand of the person blocking the discharge port 13, and the leading end of the recording medium 2 is discharged. There is a case where it is pushed out of the image forming apparatus 1 from the outlet 13. When the leading edge of the recording medium 2 is pushed out of the image forming apparatus 1 through the discharge port 13, the sensor 16 does not output a signal indicating that the paper is jammed to the control unit 50. The ROM 53 checks the stored control program for how long the paper jam signal has been continuously received. If the paper jam signal stops within the set time, the paper jam is cleared. The operation of the image forming apparatus 1 is permitted again, and the image forming apparatus 1 can be returned to use without a repair person nearby.

  As described above, the image forming apparatus 1 according to the present embodiment is opposed to the first conveyance guide 5 disposed in the sheet conveyance path 7 of the recording medium 2 and the first conveyance guide 5 across the sheet conveyance path 7. The second conveyance guide 6 arranged in this manner, the sheet conveyance path 7 for conveying the recording medium 2, the printing mechanism 19 for forming an image on the recording medium 2, and the first recording conveyance guide 5 are connected to the recording medium conveyance direction. Are provided in a direction perpendicular to the concave portion 15 and a sensor 16 that detects the recording medium 2 that has entered the concave portion 15 and moves in and out of the concave portion 15 and the paper conveyance path 7. And a piece 18.

  Accordingly, there is an effect that paper jam is unlikely to occur without increasing the size of the apparatus and even with a thin recording medium. It also has a paper jam continuation time measurement unit that measures the time during which paper jams occur continuously. If the paper jam is resolved within a predetermined time, the image forming apparatus can continue to operate. When the obstacles that existed in the printer are removed, the image forming apparatus can be operated again without the person in charge of the paper jam eliminating the paper jam error.

(Second Embodiment)
FIG. 12 is a top view showing the positions of the medium and the movable piece in another embodiment of the image forming apparatus 1 including the paper jam detecting device according to the present embodiment.

  When using the recording medium 2 having a plurality of types of media width when using the image forming apparatus 1, the movable piece 18 has a narrow width among the wide recording medium 2-2 and the narrow recording medium 2-3. The movable piece 18 was provided on the recording medium width direction center C side from the recording medium width direction end W1 of 2-3. Here, the two types of the recording medium 2-2 having a wide width and the recording medium 2-3 having a narrow width have been described. However, in the case of three or more kinds, the minimum width of the recording medium in the recording medium width direction is selected. May be provided on the center side in the recording medium width direction from the portion. When the movable piece 18 is provided on the left side in FIG. 12 from the central side C in the recording medium width direction, the movable piece 18 may be provided on the central side C in the recording medium width direction from the end W2 in the recording medium width direction.

  As a result, the recording medium 2 comes into contact with the movable piece 18 regardless of the width of the recording medium, and adverse effects on conveyance due to the recording medium 2 entering the recesses directly can be prevented.

  Although several embodiments of the present invention have been described, they are presented as the above-described embodiments, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1. Image forming apparatus 2. Recording medium 5. First conveyance guide 6. Second conveyance guide 7. Paper conveyance path 8. Thermal print head 9. Platen roller 10. Cutter 11・ Conveying roller 12 ・ ・ Idler roller 15 ・ ・ Concavity 16 ・ ・ Sensor 18 ・ ・ Moving piece 50 ・ ・ Control unit

Claims (17)

A first conveyance guide disposed in a medium conveyance path of the medium;
A second transport guide disposed opposite to the first transport guide across the medium transport path;
A medium transport unit for transporting the medium;
A recess provided in the second transport guide in a direction perpendicular to the medium transport direction;
A sensor that is provided inside the recess and detects the medium that has entered the recess;
A movable piece that is urged in a direction to enter the concave portion, and is provided in the concave portion so as to enter or retract from the bottom through a slit;
A paper jam detection device. The medium includes a roll portion wound in a roll shape,
The first conveyance guide is disposed in a medium conveyance path on a valley side of the curl of the medium,
The paper jam detection device according to claim 1, wherein the second conveyance guide is disposed in a medium conveyance path on a curl crest side of the medium.   The medium is a plurality of types of media having different media widths, and the movable piece is arranged in the direction orthogonal to the medium transport path from the widthwise end of the minimum width of the plurality of types of media in the center of the minimum width medium. The paper jam detection device according to claim 1 provided on the side.   The first transport guide and the second transport guide have a transport surface for transporting a medium, and the movable piece is the same as the transport surface of the second transport guide in a state where the upper surface has advanced into the recess. And is provided so as to guide the medium having its front end conveyed into the concave portion in the direction of the discharge port, and when a portion in front of the front end portion of the medium enters the concave portion, the medium is retracted from the concave portion. The paper jam detection device according to claim 1, wherein the paper jam detection device is biased to perform the operation.   The paper jam detection device according to claim 1, wherein the movable piece is rotatably provided on a rotation shaft provided at a lower portion of the conveyance path upstream of the concave portion.   The paper jam detection device according to claim 1, wherein the movable piece has a width on a rotation center side longer than a width of a tip portion.   The paper jam detection device according to claim 1, wherein the sensor is a reflective sensor. The sensor is
The paper jam detection device according to claim 1, wherein an end of a detectable region is provided closer to the sensor than a medium conveyance surface of the second conveyance guide. A first conveyance guide disposed in a medium conveyance path of the medium;
A second transport guide disposed opposite to the first transport guide across the medium transport path;
A medium transport unit for transporting the medium;
An image forming unit that forms an image on the medium;
A cutter for cutting the medium;
A recess provided in the second transport guide in a direction perpendicular to the medium transport direction;
A sensor that is provided inside the recess and detects the medium that has entered the recess;
A movable piece that is urged in a direction to enter the concave portion, and is provided in the concave portion so as to enter or retract from the bottom through a slit;
An image forming apparatus comprising: The medium includes a roll portion wound in a roll shape,
The first conveyance guide is disposed in a medium conveyance path on a valley side of the curl of the medium,
The image forming apparatus according to claim 9, wherein the second conveyance guide is disposed in a medium conveyance path on a curl crest side of the medium.   When the image forming apparatus receives a signal from a sensor that detects the medium that has entered the recess and a signal from the sensor that detects the medium that has entered the recess, the image forming apparatus displays on the display unit. The image forming apparatus according to claim 9, further comprising a control unit that instructs, wherein the display content of the display unit is changed when the signal is interrupted within a predetermined time.   The medium is a plurality of types of media having different media widths, and the movable piece is arranged in the direction orthogonal to the medium transport path from the widthwise end of the minimum width of the plurality of types of media in the center of the minimum width medium. The image forming apparatus according to claim 9 provided on the side.   The first transport guide and the second transport guide have a transport surface for transporting a medium, and the movable piece is the same as the transport surface of the second transport guide in a state where the upper surface has advanced into the recess. And is provided so as to guide the medium having its front end conveyed into the concave portion in the direction of the discharge port, and when a portion in front of the front end portion of the medium enters the concave portion, the medium is retracted from the concave portion. The image forming apparatus according to claim 9, wherein the image forming apparatus is urged to do so.   The image forming apparatus according to claim 9, wherein the movable piece is rotatably provided on a rotation shaft provided at a lower portion of the conveyance path upstream of the concave portion.   The image forming apparatus according to claim 9, wherein the movable piece has a width on the rotation center side longer than a width of the tip end portion.   The image forming apparatus according to claim 9, wherein the sensor is a reflective sensor. The sensor is
17. The image forming apparatus according to claim 16, wherein a detectable region end is located closer to the sensor than a medium conveyance surface of the second conveyance guide.

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