JP2018189798A - Image forming system and method for controlling image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming system that can quickly correct meander of a roll sheet and stably maintain conveyance of the roll sheet, and a method for controlling the image forming system.SOLUTION: The image forming system comprises: a meander correction part that corrects a conveyance direction of a recording medium; and a first position detection part and a second position detection part that detect the position of the recording medium. The image forming system controls the meander correction part to correct the conveyance direction of the recording medium on the basis of a result of detection performed by the first position detection part, and subsequently controls the meander correction part or an image forming part according to a result of determination as to the necessity of control of the meander correction part or the image forming part on the basis of a result of detection performed by the second position detection part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming system and an image forming system control method.

  An electrophotographic system in which a toner image formed on a photoreceptor is transferred to a recording medium such as paper, and the recording medium on which the toner image has been transferred is heated and pressed in a high-temperature fixing unit to fix the toner image on the recording medium. Image forming apparatuses are widely used. An electrophotographic image forming apparatus is applied to a copying machine, a printer apparatus, a facsimile apparatus, a printing machine, a multifunction machine, and the like.

  In this type of image forming apparatus, when the recording medium is a roll of paper (hereinafter referred to as roll paper), the roll paper snakes in the paper conveyance direction when the roll paper is conveyed to the image forming unit. It is necessary to carry so as not to.

  On the other hand, conventionally, in a printing apparatus that forms an image on a web (roll paper), a configuration in which the web meandering is detected by a web meandering sensor and the meandering correction is disclosed (Patent Document 1). FIG. 13 is a schematic configuration diagram of a printing apparatus 100 having a meandering correction mechanism in Patent Document 1.

  As shown in FIG. 13, a printing apparatus 100 described in Patent Document 1 (hereinafter referred to as a conventional printing apparatus) includes a first conveyance mechanism unit 101 via a first conveyance mechanism unit 101 and a buffer mechanism 107. And a second transport mechanism 102 provided on the downstream side in the web transport direction. Further, the printing apparatus 100 includes a first meandering detection sensor 103 and a second meandering detection sensor 104 provided between the first transport mechanism unit 101 and the buffer mechanism 107.

  The first transport mechanism unit 101 includes a transfer unit 105 that transfers an image, and the second transport mechanism unit 102 includes a fixing unit 106 that also serves as a meandering correction mechanism. The first meandering detection sensor 103 is provided on the upstream side of the buffer mechanism 107 in the transport direction of the roll paper S, and the second meandering detection sensor 104 is provided on the buffer mechanism 107 in the transport direction of the roll paper S. It is provided on the downstream side.

  In the printing apparatus 100 shown in FIG. 13, the detection result of the first meander detection sensor 103 installed at a position farther from the fixing unit 106 that also serves as a meander correction mechanism is given priority over the detection result of the second meander detection sensor 104. It is configured to perform meandering correction. With such a configuration, in the printing apparatus 100 of FIG. 13, the thermal contraction of the roll paper S caused by the heating mechanism of the fixing unit 106 is prevented from affecting the meandering correction control.

JP 2008-44750 A

  As described above, in the conventional printing apparatus 100, the detection result of the first meandering detection sensor 103 disposed at a position away from the meandering correction mechanism is preferentially used, so that it is affected by the thermal contraction of the roll paper S. A configuration for detecting the position of the roll paper S that is not accurate is employed.

  However, in the meandering correction of the roll paper S, when the meandering correction of the roll paper is performed using the detection result of the first meandering detection sensor 103 located away from the meandering correction mechanism, at the position of the second meandering detection sensor 104, The effect of meander correction appears with a delay. For this reason, when the meandering correction is performed based on the information of the first meandering detection sensor 103 as in the conventional printing apparatus 100, the time required for the meandering to stabilize at the position of the second meandering detection sensor 104 increases, and wasted paper There is a problem of increasing (paper waste).

  SUMMARY An advantage of some aspects of the invention is to provide an image forming system that can quickly correct meandering of roll paper and stably maintain the conveyance of the roll paper, and a control method for the image forming system.

  In order to solve the above problems and achieve the object of the present invention, an image forming system of the present invention is an image forming system for conveying a recording medium wound in a roll shape and forming an image on the recording medium. A forming unit, a transfer unit, and a meandering correction unit are provided. In addition, the image forming system of the present invention includes a first position detection unit, a second position detection unit, and a control unit that controls the image forming unit and the meandering correction unit. The image forming unit forms a toner image on the image carrier. The transfer unit transfers the toner image formed by the image forming unit to a recording medium. The meandering correction unit is provided on the upstream side of the image forming unit in the conveyance direction of the recording medium, and corrects the conveyance direction of the recording medium. The first position detection unit is provided on the downstream side of the meandering correction unit in the conveyance direction of the recording medium, and detects the position of the recording medium. The second position detection unit is provided downstream of the first position detection unit and upstream or downstream of the image forming unit in the conveyance direction of the recording medium, and detects the position of the recording medium. The control unit controls the meandering correction unit so as to correct the conveyance direction of the recording medium based on the detection result of the first position detection unit, and then controls the meandering correction unit or image formation based on the detection result of the second position detection unit. Control part.

  According to the control method of the image forming system of the present invention, in the image forming system, after the meander correcting unit is controlled to correct the conveyance direction of the recording medium based on the detection result of the first position detecting unit, the second method is performed. The meandering correction unit or the image forming unit is controlled based on the detection result of the position detection unit.

  According to the present invention, it is possible to quickly correct the meandering of the roll paper and stably hold the roll paper.

1 is a schematic diagram illustrating an overall configuration of an image forming system according to an embodiment of the present invention. 1 is a configuration diagram when an image forming system according to an embodiment of the present invention is viewed from above. FIG. 1 is an enlarged view of a meandering correction device of an image forming system according to an embodiment of the present invention. It is a control block diagram concerning meandering correction control of the image forming system concerning one embodiment of the present invention. 6 is a flowchart according to sheet conveyance control of the image forming system according to the embodiment of the present disclosure. 6 is a flowchart according to meandering correction control of the image forming system according to the embodiment of the present invention. 7 is a graph showing a deviation amount d2 from the target value x2 of the roll paper edge at the position of the second position detection unit when deviation amount d2 ≦ threshold value 2A in step S13 of FIG. In step S13 in FIG. 6, the deviation amount d2> the threshold value 2A, and in step S14 in FIG. 6, the target value x2 of the roll paper edge at the position of the second position detection unit when the deviation amount d2 ≦ the threshold value 2B. It is a graph which shows deviation | shift amount d2 from. 7 is a graph showing a deviation amount d2 of the end of the roll paper S at the position of the second position detection unit when deviation amount d2> threshold value 2B in step S14 of FIG. 12 is a graph showing a deviation d2 of the roll paper edge at the position of the second position detection unit when the meander correction is performed by the meander correction control process according to Comparative Example 1; 10 is a graph showing a deviation d2 of the roll paper edge at the position of the second position detection unit when the meander correction is performed by the meander correction control process according to Comparative Example 2. 14 is a graph showing a deviation d2 of the roll paper edge at the position of the second position detection unit when the meander correction is performed by the meander correction control process according to Comparative Example 3. It is a schematic block diagram which shows an example of the conventional image forming system.

Hereinafter, an example of an image forming system and an image forming system control method according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following examples. In each drawing described below, common members are denoted by the same reference numerals. The description will be given in the following order.
1. 1. Overall configuration of image forming system 2. Configuration of control system Image forming system control method

1. Overall Configuration of Image Forming System FIG. 1 is a schematic diagram showing the overall configuration of an image forming system 1 according to an embodiment of the present invention. FIG. 2 is a configuration diagram when the image forming system 1 of the present embodiment is viewed from above. As shown in FIGS. 1 and 2, the image forming system 1 of this embodiment includes a paper feeding device 2, a meandering correction device 3, an image forming device 4, and a paper discharge device 5. The image forming system 1 according to the present embodiment applies a print medium such as paper wound in a roll or a resin film as a recording medium. In the following description, a roll-shaped recording medium is referred to as “roll paper S”. It describes as.

[Paper Feeder]
The paper feeding device 2 includes a roll paper installation unit 25. In the roll paper installation unit 25, a desired roll paper main body 6 is wound around a support shaft and is installed rotatably. In addition, the paper feeding device 2 includes a paper conveyance unit (not shown) including a plurality of conveyance rollers (for example, a feeding roller, a paper supply roller, etc.) closer to the meandering correction device 3 than the roll paper installation unit 25. Have. In the paper feeding device 2, the roll paper S installed in the roll paper installation unit 25 is conveyed to the meandering correction device 3 side by the paper conveyance unit. The paper feeding operation in the paper feeding device 2 is controlled by, for example, a control unit 60 (see FIG. 4) provided in the image forming apparatus 4.

[Meander correction device]
The meandering correction device 3 is disposed on the downstream side of the paper feeding device 2 in the conveyance direction of the roll paper S and on the upstream side of the image forming device 4. FIG. 3 shows an enlarged view of the meandering correction device 3.

  As shown in FIG. 3, the meandering correction device 3 includes a first auxiliary roller 7, a meandering correction unit 27, a second auxiliary roller 10, and a first position detection unit 11. The meandering correction unit 27 includes a first meandering correction roller 8, a second meandering correction roller 9, a rotation support unit 28 that supports the first meandering correction roller 8 and the second meandering correction roller 9, and a rotation driving unit 26. With.

  The first auxiliary roller 7, the second auxiliary roller 10, the first meandering correction roller 8, and the second meandering correction roller 9 are each composed of a roller member whose length in the axial direction is longer than the length in the width direction of the roll paper S. Has been. In the present embodiment, the first auxiliary roller 7, the first meandering correction roller 8, the second meandering correction roller 9, and the second auxiliary roller 10 are arranged in this order from the upstream side to the downstream side in the conveyance direction of the roll paper S. They are arranged so that their axial directions are parallel to each other.

  Further, the first auxiliary roller 7 and the second auxiliary roller 10 are arranged at the same height (first height) in the transport direction of the roll paper S. Further, the first meandering correction roller 8 and the second meandering correction roller 9 constituting the meandering correction unit 27 are rotatably supported by the rotation support unit 28, and the height in the transport direction of the roll paper S is the same. It is arranged at a height (second height).

  Here, the second height is set to a position higher in the vertical direction than the first height. Then, the lower side of the first auxiliary roller 7, the first meandering correction roller 8, and the lower side of the first auxiliary roller 7 so that the shape of the paper conveyance path in the meandering correction device 3 becomes a U-shape that is upside down when viewed from the width direction of the roll paper S Roll paper S is wound around the upper side of the second meandering correction roller 9 and the lower side of the second auxiliary roller 10.

  In the meandering correction device 3, a conveyance unit (not shown) including a plurality of conveyance rollers is provided on the downstream side of the second auxiliary roller 10 in the conveyance direction of the roll paper S. Then, when the roll paper S is conveyed by the conveyance unit, the first auxiliary roller 7, the first meandering correction roller 8, the second meandering correction roller 9, and the second auxiliary roller 10 rotate.

  The rotation support unit 28 rotatably supports the roller support unit 13 with a roller support unit 13 that supports the first meandering correction roller 8 and the second meandering correction roller 9 and a surface parallel to the surface of the roll paper S. It comprises a support shaft 12. The roller support unit 13 includes a bottom portion 13c provided along the conveyance direction of the roll paper S, and side wall portions 13a and 13b erected at positions facing each other across the bottom portion 13c. The cross section is constituted by a U-shaped member. The roller support portion 13 rotatably supports the first meandering correction roller 8 and the second meandering correction roller 9 so as to be parallel to each other between the side wall portions 13a and 13b facing each other.

  The support shaft 12 is a surface of the bottom portion 13c constituting the roller support portion 13 on the side opposite to the surface on which the first meandering correction roller 8 and the second meandering correction roller 9 are provided. It is fixed at the axial center position on the side where it is provided. The support shaft 12 is connected to the rotation drive unit 26. When the rotation drive unit 26 is driven, the support shaft 12 rotates, and accordingly, the roller support unit 13 fixed to the support shaft 12 is a surface parallel to the paper surface of the roll paper S with the support shaft 12 as a rotation axis. Rotate. As the rotation support unit 28 rotates, the axial directions of the first meandering correction roller 8 and the second meandering correction roller 9 change. Thereby, the conveyance direction of the roll paper S wound around the 1st meander correction roller 8 and the 2nd meander correction roller 9 can be changed as shown by the arrow a of FIG.1 and FIG.2.

  In the present embodiment, the first auxiliary roller 7 and the second auxiliary roller 10 are provided on the upstream side and the downstream side of the meandering correction unit 27 in the conveyance direction of the roll paper S. It is pressed downward in the direction. Accordingly, a frictional force is generated between the first and second meandering correction rollers 8 and 9 in the meandering correction unit 27 and the roll paper S conveyed on the upper surface thereof. For this reason, when the rotation support unit 28 is rotated, the roll paper S rotates following the rotation of the first meandering correction roller 8 and the second meandering correction roller 9. Can be changed.

  The first position detection unit 11 is disposed downstream of the second meandering correction roller 9 and upstream of the second auxiliary roller 10 in the conveyance direction of the roll paper S. The first position detection unit 11 includes, for example, a mechanism such as an optical sensor or a mechanical switch, and detects the position of the end of the roll paper S in the paper width direction. The value detected by the first position detection unit 11 is sent to the calculation unit 29 (see FIG. 4), and the calculation unit 29 calculates the amount of deviation from the appropriate position of the roll paper S.

  In the present embodiment, the rotation drive unit 26 is driven and controlled according to the detection results of the first position detection unit 11 and the second position detection unit 15 to be described later, and the meandering correction is performed by changing the transport direction of the roll paper S. It is characterized by performing control. The meandering correction apparatus 3 is controlled by a control unit 60 (see FIG. 4) provided in the image forming apparatus 4, for example. This meandering correction control will be described in detail later.

[Image forming apparatus]
The image forming apparatus 4 employs an electrophotographic system in which an image is formed on the roll paper S using static electricity. Yellow (Y), magenta (M), cyan (C), and black (Bk) 4 This is a tandem type color image forming apparatus for superimposing color toners. The image forming apparatus 4 includes an image forming unit 31, a second position detecting unit 15, an intermediate transfer belt 18, a secondary transfer unit 20 (transfer unit of the present invention), a fixing unit 21, and a control unit 60 (FIG. 4).

  The image forming unit 31 has a configuration in which toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (Bk) are formed on the respective photoreceptors 14 that are image carriers. Although not shown, in addition to the photoreceptor 14, a charging unit, an exposure unit, a developing unit, and the like are provided.

  The photoconductor 14 rotates counterclockwise under the drive of a drive motor (not shown). The surface of the photoreceptor 14 is uniformly charged by the charging unit. The exposure unit performs an exposure operation on the surface of the photoconductor 14 based on image data transmitted from the outside, so that an electrostatic latent image is formed on the photoconductor 14. In each photoconductor 14, toner of each corresponding color is attached to the electrostatic latent image formed on the photoconductor 14 by the developing unit. As a result, toner images corresponding to the respective colors are formed on the respective photoreceptors 14.

  The toner adhered on each photoconductor 14 is transferred to the intermediate transfer belt 18. The toner remaining on the surface of the photoreceptor 14 after the toner is transferred to the intermediate transfer belt 18 is removed by the cleaning unit.

  The intermediate transfer belt 18 is formed in an endless shape and is stretched around a plurality of rollers 16 and 17 (two in FIG. 1). The intermediate transfer belt 18 rotates in a clockwise direction opposite to the rotation direction of the photoconductor 14 under the driving of a driving motor (not shown). A primary transfer portion (not shown) is provided at a position of the intermediate transfer belt 18 facing each photoconductor 14 in the image forming portion 31. In the primary transfer unit, a toner image formed on the photoreceptor 14 is transferred to the intermediate transfer belt 18 by applying a voltage having a polarity opposite to that of the toner to the intermediate transfer belt 18.

  As the intermediate transfer belt 18 rotates, the toner images formed on the four photoconductors 14 are sequentially transferred onto the surface of the intermediate transfer belt 18. As a result, a color image is formed on the intermediate transfer belt 18 by overlapping the yellow, magenta, cyan, and black toner images.

  The secondary transfer unit 20 is provided in the vicinity of the intermediate transfer belt 18 and at a position where the conveyed roll paper S faces the intermediate transfer belt 18. The secondary transfer unit 20 is configured by a transfer roller pair including a transfer upper roller 17 on which an intermediate transfer belt 18 is stretched and a transfer lower roller 19 pressed against the transfer upper roller 17 with the intermediate transfer belt 18 interposed therebetween. ing.

  In the secondary transfer unit 20, the roll paper S conveyed from the meandering correction device 3 side is pressed to the intermediate transfer belt 18 side by the lower transfer roller 19. The secondary transfer unit 20 transfers the color toner image formed on the intermediate transfer belt 18 onto the upper surface of the roll paper S.

  The fixing unit 21 is provided on the discharge side of the roll paper S in the secondary transfer unit 20. The fixing unit 21 includes a fixing roller 23 having a heating mechanism (not shown) and a pressure roller 22 provided at a position facing the fixing roller 23. The fixing roller 23 is heated to a predetermined temperature by a heating mechanism and rotates clockwise.

  The pressure roller 22 is provided in pressure contact with the fixing roller 23 by a pressure mechanism (not shown). The pressure roller 22 rotates in conjunction with the rotation of the fixing roller 23. A nip portion of the fixing portion 21 is formed at a portion where the fixing roller 23 and the pressure roller 22 are in contact with each other. Then, when the roll paper S carrying the toner image passes through the nip portion of the fixing unit 21, the toner is melted by heating by the fixing roller 23 and the pressure roller 22 controlled to a predetermined temperature, and the roll paper S To settle. Thereby, a desired image is formed on the roll paper S.

  In the present embodiment, the fixing roller 23 is heated by the heating mechanism. However, the present invention is not limited to this. For example, the fixing belt may be stretched around a heating roller having a fixing roller and a heating mechanism. In this case, the pressure roller is configured to come into pressure contact with the fixing belt heated to a predetermined temperature by the heating roller. In addition, the pressure roller may be a drive roller. Moreover, it can also be set as the structure which provides a heating mechanism in a pressure roller.

  The second position detection unit 15 is provided on the upstream side of the secondary transfer unit 20 in the transport direction of the roll paper S, and is disposed closer to the secondary transfer unit 20. Here, the vicinity of the secondary transfer unit 20 may be a position closer to the secondary transfer unit 20 in the image forming apparatus 4 within a range where it does not contact other rollers or components. For example, the second position detection unit 15 is preferably at a position closer to the secondary transfer unit 20 than at least an intermediate position between the supply port of the roll paper S and the secondary transfer unit 20 in the image forming apparatus 4.

  The second position detection unit 15 is configured by a mechanism such as an optical sensor or a mechanical switch, for example, and detects the position of the end of the roll paper S in the paper width direction. The value detected by the second position detection unit 15 is sent to the calculation unit 29 (see FIG. 4), and the calculation unit 29 calculates the amount of deviation from the appropriate position of the roll paper S. And the deviation | shift amount detected by the 2nd position detection part 15 is required for the meandering correction | amendment control mentioned later with the deviation | shift amount detected by the 1st position detection part 11 mentioned above.

  The control unit 60 controls each unit of the image forming apparatus 4 and the image forming system 1 in accordance with instructions from an operation display unit (not shown) or an external device (personal computer (PC) 120 shown in FIG. 4). . Details thereof will be described later.

[Paper delivery device]
The paper discharge device 5 is disposed on the downstream side of the image forming apparatus 4 in the transport direction of the roll paper S, and includes a winding unit 24 that winds up the roll paper S discharged from the image forming apparatus 4 side. . In addition, the paper discharge device 5 has a paper transport unit (not shown) that includes a plurality of transport rollers on the image forming device 4 side of the winding unit 24. The roll paper S discharged from the image forming apparatus 4 side is conveyed to the winding unit 24 side by the paper conveyance unit, and the winding unit 24 winds the conveyed roll paper S into a roll shape as needed. The paper discharge operation in the paper discharge device 5 is controlled by, for example, a control unit 60 (see FIG. 4) provided in the image forming apparatus 4.

2. Next, a control system according to the image forming system 1 of the present embodiment will be described. FIG. 4 is a block diagram showing a control system of the image forming system 1 of the present embodiment.

  As illustrated in FIG. 4, the image forming system 1 according to the present exemplary embodiment includes a paper feeding device 2, a meandering correction device 3, an image forming device 4, and a paper discharge device 5. The image forming apparatus 4 includes a control unit 60, an HDD 64, an image forming unit 31, a secondary transfer unit 20, a fixing unit 21, a second position detection unit 15, a calculation unit 29, and a comparison unit 30. With. In the present embodiment, each unit constituting the control system is connected to, for example, a PC 120 that is an external device via a system bus 121, and the control unit 60 provided in the image forming apparatus 4 includes the sheet feeding device 2 and the meander correction. Each unit of the apparatus 3, the image forming apparatus 4, and the paper discharge apparatus 5 is controlled.

  The control unit 60 includes a CPU (Central Processing Unit) 61, a ROM (Read Only Memory) 62 for storing programs executed by the CPU 61, and a RAM (Random Access Memory) 63 used as a work area of the CPU 61. Have As the ROM 62, a programmable ROM that is normally electrically erasable is used.

  In the meandering correction device 3, the position of the end of the roll paper S is detected by the first position detection unit 11 under the control of the control unit 60, and the detected data is transmitted to the calculation unit 29. Then, the calculation unit 29 calculates the deviation amount of the roll paper S at the position of the first position detection unit 11 under the control of the control unit 60.

  In the image forming apparatus 4, an image is formed on the intermediate transfer belt 18 by the image forming unit 31 based on image data transmitted from the PC 120 under the control of the control unit 60, and the secondary transfer unit 20 and the fixing unit 21. Thus, a desired image is formed on the surface of the roll paper S. Furthermore, in the image forming apparatus 4, the position of the end of the roll paper S is detected by the second position detection unit 15 under the control of the control unit 60, and the detected data is transmitted to the calculation unit 29. Then, the calculation unit 29 calculates the deviation amount of the roll paper S at the position of the second position detection unit 15.

  Under the control of the control unit 60, the comparison unit 30 compares the deviation amount of the roll paper S at the position of the first position detection unit 11 with a predetermined threshold value set in advance, and the second position detection unit 15. The amount of deviation of the roll paper S at the position is compared with a predetermined threshold value set in advance. Note that the data relating to the threshold is stored in the ROM 62 in advance. The control unit 60 drives and controls the rotation driving unit 26 in the meandering correction device 3 according to the shift amount of the roll paper S in the first position detection unit 11.

  In the present embodiment, under the control of the control unit 60, first, meandering correction is performed based on the data detected by the first position detection unit 11, and the data detected by the second position detection unit 15 after a predetermined time has elapsed. Based on the above, the necessity of meandering correction or image forming position correction is determined. Then, the meandering correction or the image forming position correction is performed according to the determination result.

  The meandering correction process control will be described in detail below.

3. Image forming system control method (meander correction control processing)
FIG. 5 is a flowchart relating to paper conveyance control of the image forming system 1 according to the present embodiment.

  In the paper conveyance control, when an instruction to start a job is received from the operation display unit (not shown) of the image forming apparatus 4 or the PC 120, the conveyance of the roll paper S is started under the control of the control unit 60 (step S1). . Here, the time when the pressure roller 22 is pressed against the fixing roller 23 side of the fixing unit 21 and the roll paper S is nipped in the nip portion is defined as the conveyance start of the roll paper S. After nipping the roll paper S by the fixing unit 21, the conveyance of the roll paper S from the paper supply device 2 side to the paper discharge device 5 side is started under the control of the control unit 60.

  Next, after the conveyance of the roll paper S from the paper supply device 2 side to the paper discharge device 5 side is started, meandering correction control is performed under the control of the control unit 60 (step S2). This meandering correction control will be described later with reference to FIG.

  Next, printing is started (step S3). At the start of printing, for example, a toner image is formed on the intermediate transfer belt 18 by the image forming unit 31 based on an image signal input from the external device 120. The toner image formed on the intermediate transfer belt 18 is transferred onto the roll paper S by the secondary transfer unit 20, and fixed on the roll paper S at the fixing unit 21.

  Next, a meandering correction control loop is started (step S4). Here, for example, the meandering correction control is performed every time the roll paper S advances by 2 m (step S5). When the predetermined printing distance is reached, the meandering correction control is terminated (step S6). The meandering correction control in step S5 is similar to the meandering correction control in step S2, and will be described in detail later.

  When the meandering correction control is completed, under the control of the control unit 60, the image formation in the image forming unit 31 is stopped and the printing is finished (step S7).

  Thereafter, under the control of the control unit 60, the pressure roller 22 is separated from the fixing roller 23 in the fixing unit 21, and the conveyance of the roll paper S is stopped by stopping the conveyance of the roll paper S (step S8). . As a result, the job ends.

  Next, the meandering correction control in step S2 and step S5 in FIG. 5 will be described. FIG. 6 is a flowchart relating to meandering correction control of the image forming system 1 according to the present embodiment. Table 1 below is a table showing a list of threshold values used in the flowchart of FIG. Each threshold in Table 1 is an absolute value. Further, the threshold value 1 in Table 1 corresponds to the “first threshold value” of the present invention, the threshold value 2A corresponds to the “second threshold value” of the present invention, and the threshold value 2B corresponds to the “third threshold value” of the present invention. It corresponds to “threshold”.

  Table 2 shows a table of waiting time t (s) with respect to the thickness of the roll paper S and the conveyance speed used in the flowchart of FIG. Table 2 shows the waiting time t (s) when the distance from the meandering correction unit 27 to the second position detection unit 15 is 600 mm.

  The tables shown in Tables 1 and 2 are stored in the ROM 62 in advance and are referred to as necessary.

  The meandering correction control is started when a meandering correction control instruction is issued in step S2 or step S5 of FIG. In the meandering correction control, first, meandering correction is performed according to the shift amount d1 of the roll paper S at the position of the first position detection unit 11 (step S10).

  In step S <b> 1, first, the position of the end portion of the roll paper S is detected by the first position detection unit 11 under the control of the control unit 60. Next, under the control of the control unit 60, the position information detected by the first position detection unit 11 is sent to the calculation unit 29, which calculates the end of the roll paper S at the position of the first position detection unit 11. Is calculated with respect to a target position (hereinafter, target value x1). Here, the target value x1 is set to a position where the end of the roll paper S passes at the position of the first position detection unit 11 when the roll paper S is conveyed without meandering.

  After that, under the control of the control unit 60, the rotation support unit 28 is rotated by drivingly controlling the rotation drive unit 26 according to the shift amount d1 of the roll paper S at the position of the first position detection unit 11. Then, the conveyance direction of the roll paper S is corrected. At this time, the rotation drive unit 26 rotates the rotation support unit 28 so that the shift amount d1 becomes 0 under the control of the control unit 60.

  Next, it is determined whether or not the shift amount d1 of the roll paper S at the position of the first position detector 11 is equal to or less than a threshold value (step S11). In step S <b> 11, first, the position of the end of the roll paper S is detected by the first position detection unit 11 again under the control of the control unit 60, and the detected position information is sent to the calculation unit 29. Then, under the control of the control unit 60, the calculation unit 29 calculates a shift amount d1 of the end portion of the roll paper S at the position of the first position detection unit 11 with respect to the target value x1. Thereafter, under the control of the control unit 60, the comparison unit 30 determines whether or not the shift amount d1 of the roll paper S at the position of the first position detection unit 11 is equal to or less than the threshold value 1 in Table 1.

  If it is determined as “NO” in step S11, that is, if it is determined that the shift amount d1 of the roll paper S at the position of the first position detection unit 11 is larger than the threshold value 1 in Table 1, again, Return to step S10. That is, in step S11, the process in step S10 is repeated until it is determined that the amount of deviation d1 of the roll paper S at the position of the first position detection unit 11 is equal to or less than the threshold value 1.

  On the other hand, when it is determined “YES” in step S11, that is, when it is determined that the shift amount d1 of the roll paper S at the position of the first position detection unit 11 is equal to or less than the threshold 1 in Table 1, The controller 60 waits for a predetermined waiting time t (s) shown in Table 2 until the next processing (step S12). The waiting time t (s) indicates the time until the roll paper S that has passed through the position of the first position detection unit 11 reaches the position of the second position detection unit 15 at the timing of step S11. As shown in Table 2, the waiting time t (s) varies depending on the paper type of the roll paper S and the conveyance speed. For example, the paper type of the roll paper S is changed by the PC 120 or the like before starting the job. It can be set by setting. During the waiting time t (s), the roll paper S is continuously conveyed.

  Next, it is determined whether or not the shift amount d1 of the roll paper S at the position of the second position detection unit 15 is equal to or less than the threshold value 2A (step S13). In step S <b> 13, under the control of the control unit 60, the position of the end portion of the roll paper S is detected by the second position detection unit 15, and the detected position information is sent to the calculation unit 29. Then, under the control of the control unit 60, the calculation unit 29 calculates a deviation amount d2 of the end portion of the roll paper S at the position of the second position detection unit 15 with respect to the target position (hereinafter, target value x2). Here, the target value x2 is the second position detection when the roll paper S is conveyed without meandering so that the image forming position in the secondary transfer unit 20 falls within a predetermined image forming range. The position of the section 15 is set to a position where the end of the roll paper S passes.

  After calculating the deviation amount d2, under the control of the control unit 60, the comparison unit 30 determines whether the deviation amount d2 of the roll paper at the position of the second position detection unit 15 is equal to or less than the threshold value 2A in Table 1. To do. Here, in this embodiment, the threshold value 2A = 0.1 mm, but the threshold value 2A is set according to the amount of deviation of the roll paper S allowed in the secondary transfer unit 20, that is, It is appropriately set depending on the required image forming position accuracy.

  When it is determined “YES” in step S13, that is, when it is determined that the deviation d2 of the roll paper S at the position of the second position detection unit 15 is equal to or less than the threshold 2A, the meander correction process is performed. End control.

  On the other hand, if “NO” is determined in the step S13, that is, if it is determined that the deviation amount of the roll paper at the position of the second position detection unit is larger than the threshold 2A, the second position detection unit 15 It is determined whether or not the shift amount d2 of the roll paper S at the position is equal to or less than the threshold value 2B (step S14).

  In step S14, under the control of the control unit 60, the comparison unit 30 determines whether or not the shift amount d2 of the roll paper S at the position of the second position detection unit 15 acquired in step S13 is equal to or less than the threshold value 2B in Table 2. Determine whether. In this embodiment, the threshold value 2B is set to 0.5 mm, but the threshold value 2B is set to the maximum value of the deviation amount of the roll paper S allowed in the secondary transfer unit 20.

  For example, when a label tack paper in which glue is applied to the end of the roll paper S is used as the roll paper S, if the end of the roll paper S enters the image forming range, the glue that comes out of the end of the roll paper S is used. May cause image defects in other jobs. Therefore, the threshold value 2B is such that, at the position of the secondary transfer unit 20, the end of the roll paper S does not enter the image forming range, and a margin with a predetermined interval is formed between the end of the roll paper S and the image forming range. Is preferably set within a range.

  First, the case where it is determined as “YES” in step S14, that is, the case where it is determined that the shift amount d2 of the roll paper S at the position of the second position detection unit 15 is equal to or less than the threshold 2B will be described. The condition set as “YES” in step S14 is a case where the required image forming position accuracy is not satisfied, but the shift amount d2 of the roll paper S in the secondary transfer unit 20 is within an allowable range. In this case, the image writing position is corrected according to the shift amount d2 of the roll paper S at the position of the second position detector 15 (step S15). The correction of the image writing position can be performed by correcting the formation position of the toner image written on the photoreceptor 14 in the image forming unit 31.

  That is, in step S14, the shift amount d2 from the target value x2 of the roll paper S at the position of the second position detection unit 15 is corrected by shifting the formation position of the image formed on the roll paper S, and the original roll paper A desired image is formed at the S image forming position. Then, the meandering correction control ends.

  On the other hand, a case where “NO” is determined in step S14, that is, a case where it is determined that the roll paper S deviation amount d2 in the second position detection unit 15 is larger than the threshold 2B will be described. The condition of “NO” in step S14 is a case where the required image forming position accuracy is not satisfied and the amount of deviation d2 of the roll paper S in the secondary transfer unit 20 is not within the allowable range. In this case, the target value x1 at the position of the first position detector 11 is corrected according to the shift amount d2 of the roll paper S at the position of the second position detector 15.

  In step S14, for example, the target value x1 in the first position detector 11 is corrected so that the shift amount d2 of the roll paper S at the position of the second position detector 15 is equal to or less than the threshold 2A in step S13. A new target value x1 is set, and the control in step S10 is performed. That is, after the target value x1 itself in the first position detection unit 11 is set as a new target value x1, the deviation d1 from the new target value x1 of the roll paper S at the position of the first position detection unit 11 is again set. Based on this, the meandering correction unit 27 is rotated to perform meandering correction.

  Thereafter, in the same manner as described above, the meandering correction control is terminated by the control processing after step S11. Then, as shown in FIG. 5, for example, by performing the meandering correction control every time the roll paper S advances by 2 m, it is possible to always correct the meandering and image forming position of the roll paper S during the printing period. it can.

  7 to 9 are graphs showing a deviation d2 from the target value x2 at the end of the roll paper S at the position of the second position detection unit 15 when the meandering correction control is performed in the present embodiment. 7 to 9, the horizontal axis represents the elapsed time, and the vertical axis represents the deviation d2 from the target value x2 at the end of the roll paper S at the position of the second position detection unit 15.

  7 to 9, “conveyance start” indicates a point in time when the pressure roller 22 and the fixing roller 23 are pressed against each other in the fixing unit 21, and “conveyance end” indicates the pressure roller 22 and the fixing roller 23 in the fixing unit 21. Indicates the point of time when the pressure contact is released. 7 to 9, “print start” indicates a time point at which image formation is started in the image forming unit 31, and “print end” indicates a time point at which image formation is ended in the image forming unit 31.

  In general, in the fixing unit 21, the position of the roll paper S is shifted before and after the press contact between the pressure roller 22 and the fixing roller 23. The amount of deviation of the roll paper S caused by pressing the pressure roller 22 and the fixing roller 23 in the fixing unit 21 is slightly different depending on each device. In the image forming system 1, the transport position of the roll paper S is set in consideration of the shift amount of the roll paper S due to the pressure contact in the fixing unit 21.

  In the present embodiment, the end portion of the roll paper S at the time when the pressure roller 22 and the fixing roller 23 are not in pressure contact with each other in the fixing unit 21 is at a position of the second position detection unit 15 from the target value x2 to −2 mm. It shall be arranged at a position. For this reason, in FIGS. 7 to 9, the shift amount d <b> 2 is −2 mm before the start of transport and after the start of transport.

  FIG. 7 is a graph showing the amount of deviation d2 from the target value x2 at the end of the roll paper S at the position of the second position detector 15 when the amount of deviation d2 ≦ threshold 2A in step S13 of FIG. is there.

  As shown in FIG. 7, in step S <b> 13, when deviation amount d <b> 2 ≦ threshold 2 </ b> A, the meander correction is sufficiently performed by the meander correction according to the detection result of the first position detection unit 11 in step S <b> 10. . Accordingly, the position of the end of the roll paper S at the position of the second position detection unit 15 reaches the target value x2 about 10 seconds after the start of conveyance, and the roll paper S is supplied to the secondary transfer unit 20 without meandering. Is done.

  FIG. 8 shows the roll paper S at the position of the second position detector 15 when the deviation amount d2> the threshold value 2A in step S13 of FIG. 6 and the deviation amount d2 ≦ the threshold value 2B in step S14 of FIG. It is a graph which shows deviation | shift amount d2 from the target value x2 of an edge part.

  As shown in FIG. 8, when the deviation amount d2> the threshold value 2A in step S13 in FIG. 6 and the deviation amount d2 ≦ the threshold value 2B in step S14 in FIG. 6, the meandering itself converges, but the roll paper The sheet S is conveyed to the secondary transfer unit 20 in a state of being shifted by a shift amount d2. However, in this case, in step S15 in FIG. 6, the image writing position in the image forming unit 31 is corrected according to the shift amount d2 in the position of the second position detecting unit 15. As a result, the amount of deviation d2 in FIG. 8 can be corrected at the image forming position, so that an image can be formed at a desired position on the roll paper S.

  FIG. 9 is a graph showing the shift amount d2 of the end portion of the roll paper S at the position of the second position detection unit 15 when the shift amount d2> the threshold value 2B in step S14.

  As shown in FIG. 9, when the deviation amount d2> threshold value 2B in step S14, the target value x1 of the position of the end of the roll paper S at the position of the first position detection unit 11 is corrected, and the correction is performed. The processing after step S10 in FIG. 6 is performed on the new target value x1. Thereby, the position of the end of the roll paper S at the position of the second position detection unit 15 reaches the target value x2, and the roll paper S is supplied to the secondary transfer unit 20 without being displaced.

  7 to 9, the print start time is 15 seconds after the start of the job. For example, when the meandering of the roll paper S is corrected at a timing earlier than 15 seconds as shown in FIG. Can also be set to advance the print start time.

  As shown in FIGS. 7 to 9, in the meandering correction control of the present embodiment, the meandering correction is performed using the detection result detected by the first position detection unit 11, and then detected by the second position detection unit 15. The necessity of the meander correction is determined using the detected result, and the meander correction is performed according to the determination result. Thereby, the conveyance position of the roll paper S is corrected to a more accurate position as compared with the case where the meandering correction is performed using the detection result of only the first position detection unit 11 or the second position detection unit 15. Can do. Further, depending on the transport position of the roll paper S, it is possible to form an image at a more accurate position of the roll paper S by correcting the image formation position in the image forming unit 31.

  By the way, when there is a meandering detection sensor downstream of the transfer unit 105 in the conveyance direction of the roll paper S as in the conventional printing apparatus 100, the conveyance position of the roll paper at the position of the transfer unit 105 is unknown. The deviation of the roll paper S cannot be corrected by correcting the image forming position.

  On the other hand, in the present embodiment, by providing the second position detection unit 15 in the vicinity of the secondary transfer unit 20 in the conveyance direction of the roll paper S, when the deviation amount of the roll paper S is fine, The image position can be corrected.

  10 to 12 are graphs showing the deviation amount of the roll paper end portion of the image forming system according to Comparative Examples 1 to 3. FIG. 10 to 12, similarly to FIGS. 7 to 9, the shift amount d <b> 2 is measured from the target value x <b> 2 at the end of the roll paper S at the position of the second position detection unit 15 in the present embodiment.

[Comparative Example 1]
FIG. 10 shows the second position detection unit 15 when the meandering correction is performed by a method in which the regulating member is directly brought into contact with the end portion in the width direction of the roll paper S without using the meandering correction device 3 of the present embodiment. It is a graph which shows deviation | shift amount d2 from the target value x2 of the roll paper S edge part in a position. As shown in FIG. 10, when the meandering correction device 3 is not used, the roll paper S may meander from the start of printing to the end of printing.

[Comparative Example 2]
FIG. 11 is a graph showing the amount of deviation d2 from the target value x2 of the end of the roll paper S at the position of the second position detection unit 15 when only the meandering correction based on the detection result of the first position detection unit 11 is performed. It is. That is, FIG. 11 is an example in which the meandering correction control is terminated in step S11 of FIG. 6 and the correction based on the detection result of the second position detection unit 15 is not performed.

  As shown in FIG. 11, when only the meandering correction based on the detection result of the first position detection unit 11 is performed, the position of the end of the roll paper S from the target value x2 at the position of the second position detection unit 15. It may deviate greatly. This is because the first position detection unit 11 is arranged at a position away from the secondary transfer unit 20, and the meandering correction is performed based on the detection result of the first position detection unit 11 arranged at that position. Because of that. And since this deviation | shift amount d2 changes with paper types and paper width | variety, it cannot set so that only a fixed amount may shift | deviate beforehand.

  Further, the conveyance position of the roll paper S at the position of the secondary transfer unit 20 is changed by changing the conveyance force of the conveyance roller during printing or by gradually moving the winding position in the paper discharge device 5 in the front-rear direction. It may move over time. Therefore, even if the shift amount at the position of the first position detection unit 11 is suppressed, the shift amount of the roll paper S in the secondary transfer unit 20 cannot be suppressed.

[Comparative Example 3]
FIG. 12 is a graph showing the amount of deviation d2 from the target value x2 at the end of the roll paper S at the position of the second position detection unit 15 when only the meandering correction based on the detection result of the second position detection unit 15 is performed. It is. That is, FIG. 11 ends the meandering correction control by controlling the meandering correction unit 27 so that the deviation d2 from the target value x2 of the end of the roll paper S at the position of the second position detection unit 15 is equal to or less than the threshold value. In this example, meandering correction based on the detection result in the first position detector 11 is not performed.

  As shown in FIG. 12, when only the meandering correction based on the detection result of the second position detection unit 15 is performed, the second position detection unit 15 is arranged at a position away from the meandering correction unit 27. The correction at the position of the correction unit 27 takes effect with a delay. For this reason, there is a problem that it takes time until the meandering of the roll paper S converges, and the meandering correction is not in time for the print start timing.

  In the image forming system 1 of the present embodiment, first, meander correction is performed using the detection result of the first position detection unit 11 provided in the vicinity of the meander correction unit 27. Next, if necessary, the image forming position is corrected or the meandering is corrected based on the detection result of the second position detection unit provided in the vicinity of the secondary transfer unit 20. Thereby, the meandering of the roll paper S can be stabilized more quickly than in Comparative Examples 1 to 3. As described above, in the present embodiment, the time until the meander correction is completed can be shortened as compared with Comparative Examples 1 to 3, so that an increase in the amount of scraped paper can be suppressed and the start of printing can be accelerated. .

  Further, in the present embodiment, the second position detection unit 15 is provided in the vicinity of the secondary transfer unit 20. For this reason, when the amount of deviation d2 from the target value x2 at the end of the roll paper S at the position of the second position detector 15 is within a certain threshold, the roll paper S can be accurately detected by changing the image forming position. An image can be formed at the position.

  In the present embodiment, the second position detection unit 15 is provided on the upstream side of the secondary transfer unit 20 in the transport direction of the roll paper S, but may be provided on the downstream side. Even when the second position detection unit 15 is provided on the downstream side of the secondary transfer unit 20 in the transport direction of the roll paper S, it is preferable to arrange the second position detection unit 15 closer to the secondary transfer unit 20, for example, secondary transfer It is preferable to arrange in a section between the part 20 and the fixing part 21.

  In the present embodiment, the first position detection unit 11 is disposed downstream of the meandering correction unit 27 and upstream of the second auxiliary roller 10 in the conveyance direction of the roll paper S. The present invention is not limited to this, and it may be arranged between the meandering correction unit 27 and the image forming unit 31.

  Further, in the present embodiment, in step S14 in the meandering correction control of FIG. 6, when the deviation amount d2 ≦ the threshold value 2B, the writing position in the image forming unit 31 is corrected. However, the present invention is not limited to this. For example, when the shift amount d2> the threshold value 2A in step S13, all of the steps may be shifted to step S16 without performing step S14.

  The above-described exemplary embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. For example, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Moreover, it is possible to add / delete / replace other configurations for a part of the configurations of the embodiments.

  DESCRIPTION OF SYMBOLS 1 ... Image forming system, 2 ... Paper feeding apparatus, 3 ... Meandering correction apparatus, 4 ... Image forming apparatus, 5 ... Paper discharge apparatus, 6 ... Roll paper main body, 7 ... 1st auxiliary roller, 8 ... 1st serpentine correction roller , 9 ... second meandering correction roller, 10 ... second auxiliary roller, 11 ... first position detection unit, 12 ... support shaft, 13 ... roller support part, 13a ... side wall part, 13c ... bottom part, 14 ... photoconductor, 15 2nd position detection unit, 18 ... intermediate transfer belt, 20 ... secondary transfer unit, 21 ... fixing unit, 24 ... winding unit, 25 ... roll paper installation unit, 25 ... image forming unit, 27 ... meandering correction unit, 28: Rotation support unit, 29: Calculation unit, 30 ... Comparison unit, 31 ... Image forming unit

Claims (8)

An image forming system for conveying a recording medium wound in a roll and forming an image on the recording medium,
An image forming unit for forming a toner image on the image carrier;
A transfer unit that transfers the toner image formed by the image forming unit to the recording medium;
A meandering correction unit that is provided upstream of the image forming unit in the conveyance direction of the recording medium and corrects the conveyance direction of the recording medium;
A first position detection unit that is provided downstream of the meandering correction unit in the conveyance direction of the recording medium and detects the position of the recording medium;
A second position detection unit that is provided downstream of the first position detection unit and upstream or downstream of the image forming unit in the conveyance direction of the recording medium, and detects the position of the recording medium;
After controlling the meandering correction unit to correct the conveyance direction of the recording medium based on the detection result of the first position detection unit, the meandering correction unit or the based on the detection result of the second position detection unit An image forming system comprising: a control unit that controls the image forming unit. The control unit, based on the detection result of the first position detection unit, the transfer position of the recording medium at the position of the first position detection unit, and the target transfer position at the position of the first position detection unit, The image forming system according to claim 1, wherein the meandering correction unit is corrected to correct the conveyance direction of the recording medium until a deviation amount of the recording medium becomes equal to or less than a first threshold value. The control unit, based on the detection result of the second position detection unit, the transfer position of the recording medium at the position of the second position detection unit, and the target transfer position at the position of the second position detection unit, The image forming system according to claim 2, wherein the meandering correction control is terminated when the amount of deviation is equal to or less than the second threshold value. The control unit, based on the detection result of the second position detection unit, the transfer position of the recording medium at the position of the second position detection unit, and the target transfer position at the position of the second position detection unit, 3. The image forming system according to claim 2, wherein the image forming position in the image forming unit is corrected when the amount of deviation is larger than the second threshold and equal to or smaller than the third threshold. The control unit, based on the detection result of the second position detection unit, the transfer position of the recording medium at the position of the second position detection unit, and the target transfer position at the position of the second position detection unit, When the deviation amount is larger than the second threshold and larger than the third threshold, after correcting the target transport position at the position of the first position detection unit,
Based on the detection result of the first position detector, the amount of deviation between the transport position of the recording medium at the position of the first position detector and the target transport position at the position of the first position detector is The image forming system according to claim 2, wherein the meandering correction unit is corrected until the first threshold value becomes the following. The image forming system according to claim 1, wherein the second position detection unit is provided between the meandering correction unit and the transfer unit. The image forming system according to claim 1, wherein the second position detection unit is provided on the downstream side of the transfer unit in the conveyance direction of the recording medium. An image forming unit for forming a toner image on the image carrier;
A transfer unit that transfers the toner image formed by the image forming unit to a recording medium;
A meandering correction unit that is provided upstream of the image forming unit in the conveyance direction of the recording medium and corrects the conveyance direction of the recording medium;
A first position detection unit that is provided downstream of the meandering correction unit in the conveyance direction of the recording medium and detects the position of the recording medium;
A second position detection unit that is provided downstream of the first position detection unit and upstream or downstream of the image forming unit in the conveyance direction of the recording medium, and detects the position of the recording medium;
A control unit for controlling the image forming unit and the meandering correction unit,
A control method of an image forming system for conveying a recording medium wound in a roll and forming an image on the recording medium,
The control unit controls the meandering correction unit to correct the conveyance direction of the recording medium based on the detection result of the first position detection unit, and then based on the detection result of the second position detection unit. A control method of an image forming system for controlling a meandering correction unit or the image forming unit.

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