JP6528554B2 - Image forming apparatus and image forming system - Google Patents

Description

  The present invention relates to an image forming apparatus for transferring and fixing a toner image on a long sheet to form an image, and an image forming system provided with the image forming apparatus.

  Conventionally, an electrophotographic image forming apparatus is known as a printer, a copying machine, and the like. In such an image forming apparatus, when conveying a sheet to form an image, the sensor detects the leading end, the trailing end, etc. of the sheet to adjust the sheet tension between the transfer portion and the fixing portion. To adjust the speed at the fixing unit.

  In the configuration for transporting a long sheet, there is known a technique for adjusting the load applied to the sheet feeding unit of the long sheet by adjusting the friction load applied to the long sheet manually (for example, Patent Document 1) reference).

Unexamined-Japanese-Patent No. 2003-81502

  In the configuration for transporting the long paper, a guide member for guiding the long paper is provided in the paper feeding unit, and the long paper is transported in a state of being in contact with the guide member. The tension is not constant and always fluctuates. In addition, depending on the type of long paper, the coefficient of friction and stiffness differ, and the optimum tension varies.

  In the configuration in which the tension of the long paper is manually adjusted, the tension can not be adjusted during the conveyance of the long paper, so that the fluctuation of the tension during the conveyance can not be followed, and the tension of the long paper is properly adjusted. It is difficult to adjust to a reasonable value. Further, even if a tension applying device called a dancer is provided, it is not possible to follow fluctuations in tension during conveyance, and it is difficult to adjust the tension of a long sheet to an appropriate value.

  Furthermore, since the long paper is conveyed in a tensioned state, the sensor for detecting the displacement of the position due to the bending of the long paper is used as a configuration for detecting the tension of the long paper. I can not

  In addition, if the linear velocity of the fixing unit is adjusted to adjust the tension of the long paper, a difference occurs in the linear velocity between the transfer unit and the fixing unit, and both the linear velocity difference and the tension change. It will be very difficult. In particular, if the linear velocity difference between the transfer portion and the fixing portion is dispersed, the long paper run-off and color registration become significantly unstable.

  As a result, it has been extremely difficult to adjust the linear speed at the fixing unit and to adjust the tension of the long sheet by manually adjusting the frictional load at the sheet feeding unit.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an image forming apparatus and an image forming system capable of controlling tension in accordance with fluctuations in tension accompanying conveyance of a long sheet. I assume.

In order to solve the problems described above, the invention according to claim 1 has a transfer means for transferring toner onto a long sheet, and an image is formed by the image forming means for forming an image on the long sheet, and the image forming means The fixing means for fixing the image on the long sheet of paper, the fixing and conveying means for conveying the long sheet by the fixing means, and the fixing and conveying means are driven to detect electricity flowing to the fixing and conveying means, and Control means for controlling the frictional load applied to the long paper by the tension applying means provided on the upstream side of the image forming means with respect to the transport path of the long paper based on the change of the state of electricity according to the applied load ; The fixing and conveying unit is an image forming apparatus that is a motor that drives a fixing and conveying member that conveys the long sheet in contact with the long sheet .

  According to the second aspect of the present invention, the control means sets the appropriate range of tension of the long sheet as the appropriate tension information and, based on the state of electricity flowing through the fixing and conveying means, the tension of the long sheet The image forming apparatus according to claim 1, wherein control information to be an appropriate range is set based on the tension information.

The invention according to claim 3, control means, current status of the electricity flowing through the motor that is driven to rotate, detected from the voltage value or resistance value, the current value of the electricity flowing through the motor, a voltage value or resistance The image forming apparatus according to claim 1 or 2, wherein the frictional load applied to the long sheet is controlled by the tension applying unit based on the value.

  In the invention according to claim 4, the control means sets the appropriate tension information corresponding to the sheet information for specifying the type of the long sheet, and the appropriate tension information is set by selection of the sheet information. An image forming apparatus according to claim 2 or claim 3.

  In the invention according to claim 5, the control means is configured to select appropriate tension information set corresponding to the sheet information for specifying the type of the long sheet. It is an image forming apparatus.

In the invention according to claim 6, the tension applying means controls the frictional load applied to the long paper by changing the winding amount of the long paper on the tension applying roller which rotates in contact with the long paper. The image forming apparatus according to any one of claims 1 to 5.

In the invention according to claim 7, the tension applying means controls the friction load applied to the long sheet by switching the rotation state and the stop state of the tension applying roller which is rotated following the conveyance of the long sheet. An image forming apparatus according to any one of claims 1 to 6.

In the invention according to claim 8, the tension applying means is provided with a resistance applying means which applies a load in the rotation direction of the tension applying roller which rotates following the conveyance of the long sheet and makes the load variable. The image forming apparatus according to any one of claims 1 to 5, wherein the frictional load applied to the sheet is controlled.

The invention according to claim 9, tensioning means, moves in a state of tension application roller rotated by the conveyance of the long paper, a load is applied to a linear direction orthogonal to the transport direction of the long paper The image forming apparatus according to any one of claims 1 to 5, wherein the frictional load applied to the long sheet is controlled by enabling the control.

According to a tenth aspect of the present invention, there is provided an image forming apparatus, a sheet feeding apparatus for storing a long sheet fed to the image forming apparatus, and a sheet feeding apparatus for feeding a long sheet from the sheet feeding apparatus to the image forming apparatus The image forming apparatus includes a device and a sheet collection device for storing a long sheet on which an image is formed by the image forming apparatus. The image forming apparatus includes transfer means for transferring toner to the long sheet, and the image is printed on the long sheet. By driving an image forming unit to be formed, a fixing unit to fix an image on a long sheet on which an image is formed by the image forming unit, a fixing and conveying unit to convey a long sheet by the fixing unit, and a fixing and conveying unit Control means for detecting the electricity flowing to the fixing and conveying means, and controlling the friction load applied to the long sheet by the tension applying means provided to the sheet feeding device based on the change of the state of electricity according to the load applied to the fixing and conveying means comprising a fixing conveying means, in contact with the long paper The image forming system is a motor that drives the fixing conveying member for conveying the continuous paper.

According to the present invention, by driving the fixing conveyance member for conveying the long sheet by the fixing means, the electricity flowing to the motor is detected, and the tensioning is applied based on the change of the state of electricity according to the load applied to the fixing conveyance member. By controlling the friction load applied to the long paper by the means, the tension of the long paper can be controlled to an appropriate value without changing the linear velocity in the fixing means.

FIG. 1 is a block diagram showing an example of an image forming apparatus of the present embodiment. FIG. 1 is a configuration diagram showing an example of an image forming system of the present embodiment. It is a block diagram which shows an example of the tension provision apparatus of this Embodiment. It is a block diagram which shows the other example of the tension provision apparatus of this Embodiment. FIG. 2 is a functional block diagram showing an example of control functions of the image forming apparatus and the image forming system of the present embodiment. 5 is a flowchart showing an example of the operation of the image forming apparatus and the image forming system of the present embodiment. It is explanatory drawing which shows the outline | summary of the appropriate range of the tension of a long paper.

  Hereinafter, embodiments of an image forming apparatus and an image forming system of the present invention will be described with reference to the drawings.

<Configuration Example of Image Forming Apparatus and Image Forming System According to Embodiment>
FIG. 1 is a block diagram showing an example of an image forming apparatus according to the present embodiment, and FIG. 2 is a block diagram showing an example of an image forming system according to the present embodiment.

  The image forming apparatus 1A of the present embodiment is an electrophotographic image forming apparatus such as a copying machine. In this example, a plurality of photosensitive members are arranged in the longitudinal direction so as to face one intermediate transfer belt. It is a so-called tandem type color image forming apparatus which forms a full color image by the above.

  The image forming system 110 according to the present embodiment is configured to form an image on a long sheet P1 by the image forming apparatus 1A. As shown in FIG. 2, the image forming system 110 includes an image forming apparatus 1A, a sheet feeding apparatus 120 in which a long sheet P1 fed to the image forming apparatus 1A is stored, and an image forming apparatus from the sheet feeding apparatus 120. The sheet feeding apparatus 130 is provided to feed the long sheet P1 to 1A. The image forming system 110 further includes a sheet collection device 140 in which the long sheet P1 on which the image is formed by the image forming apparatus 1A is stored.

  Here, the long paper P1 in the present embodiment is a label in which a label is attached to a paper, a film, or a release paper that is longer than the length of the conveyance path between the paper feed port and the discharge port in the image forming apparatus 1A. It is paper etc.

  In the sheet feeding device 120, a roll sheet P11 in a form in which a long sheet P1 is wound is supported by the shaft 121, and the long sheet P1 is accommodated so as to be able to be fed out by the rotation of the roll sheet P11.

  The sheet feeding device 130 includes a sheet feeding roller 131 that feeds out and conveys the long sheet P1 from the sheet feeding device 120, and a tension applying device 132 that applies tension to the long sheet P1 in cooperation with the image forming apparatus 1A.

  FIG. 3 is a block diagram showing an example of the tension applying device of the present embodiment. The tension applying device 132 is an example of a tension applying unit, and a first tension applying roller 132a in contact with the front surface of the long sheet P1 and a second contact in contact with the back surface of the long sheet P1. And a tension applying roller 132b.

  The tension applying device 132 moves the roller position to move either or both of the first tension applying roller 132 a and the second tension applying roller 132 b in a direction substantially orthogonal to the conveyance direction of the long sheet P 1 A device 133 is provided. Thus, the tension application device 132 is configured to be able to control the relative position of the first tension application roller 132a and the second tension application roller 132b in the direction substantially orthogonal to the conveyance direction of the long paper P1. Ru.

  The tension applying device 132 relatively moves the first tension applying roller 132 a and the second tension applying roller 132 b in a direction substantially orthogonal to the conveyance direction of the long paper P 1 to obtain the long paper P 1. Change the amount of wrapping.

  In the tension applying device 132, as shown by a solid line in FIG. 3, the first tension applying roller 132a and the second tension applying roller 132b are moved relative to each other in the direction in which the distance approaches each other. The winding amount L1 of the long paper P1 with respect to the tension applying roller 132a and the second tension applying roller 132b is reduced.

  In the tension application device 132, the frictional load on the long paper P1 is reduced by reducing the amount L1 of the long paper P1 to be wound on the first tension application roller 132a and the second tension application roller 132b, and the long operation is performed. The tension applied to the paper P1 is weakened.

  On the other hand, in the tension applying device 132, as shown by the alternate long and short dash line in FIG. 3, the first tension applying roller 132a and the second tension applying roller 132b are relatively moved in the direction in which the distance therebetween is separated. Thus, the amount L2 of winding of the long paper P1 with respect to the first tension applying roller 132a and the second tension applying roller 132b is increased.

  In the tension application device 132, the friction load on the long sheet P1 is increased by increasing the winding amount L2 of the long sheet P1 with respect to the first tension application roller 132a and the second tension application roller 132b. The tension applied to the paper P1 is intensified. Therefore, in the tension application device 132, the strength of tension applied to the long sheet P1 being conveyed is configured to be adjustable.

  FIG. 4 is a block diagram showing another example of the tension applying device of the present embodiment. As another configuration of the tension applying device 132, a braking device 134 that controls the rotation operation of the first tension applying roller 132a and / or the second tension applying roller 132b is provided.

  As a result, the tension application device 132 can rotate according to the conveyance of the long sheet P1 in at least one of the first tension application roller 132a and the second tension application roller 132b. It is configured to be able to control the switching of the stop state not following the conveyance of P1.

  In the tension application device 132, by setting at least one of the first tension application roller 132a and the second tension application roller 132b in rotation, the friction load on the long paper P1 is reduced, and the tension applied to the long paper P1. Is weakened.

  On the other hand, in the tension applying device 132, by setting at least one of the first tension applying roller 132a and the second tension applying roller 132b in a stopped state, the frictional load on the long paper P1 is increased, and the long paper is long. The tension on P1 is strengthened. Therefore, in the tension application device 132, the strength of tension applied to the long sheet P1 being conveyed is configured to be adjustable.

  Here, both the roller position moving device 133 and the braking device 134 are provided, and control of the winding amount of the long paper P1 with respect to the first tension applying roller 132a and the second tension applying roller 132b, and long paper The strength of tension applied to the long sheet P1 to be conveyed may be adjusted in both of the control of the rotational operation following the conveyance of P1.

  The tension applying device 132 is rotated by an urging means such as a spring when the roller is driven to rotate by at least one of the first tension applying roller 132a and the second tension applying roller 132b as a resistance applying means. The load may be applied in the direction, and a torque limiter may be provided to make the load variable. In addition, an oil damper may be provided which applies a load with oil pressure in the rotational direction and makes the load variable.

  The tension applying device 132 rotates the first tension applying roller 132a and the second tension applying roller 132a when the first tension applying roller 132a and the second tension applying roller 132b are driven by the conveyance of the long sheet P1. By reducing the load in the rotational direction of at least one of the application rollers 132b, the frictional load on the long paper P1 is reduced, and the tension applied to the long paper P1 is weakened.

  On the other hand, in the tension applying device 132, by increasing the load in the rotational direction, the frictional load on the long sheet P1 is increased, and the tension applied to the long sheet P1 is strengthened. Therefore, in the tension application device 132, the strength of tension applied to the long sheet P1 being conveyed is configured to be adjustable.

  Further, the tension applying device 132 can move one of the first tension applying roller 132a and the second tension applying roller 132b in a state in which a load is applied in a direction substantially orthogonal to the conveyance direction of the long paper P1. In the configuration referred to as a dancer roller, the load may be controlled to be variable.

  The tension applying device 132 is long by reducing the load applied when the first tension applying roller 132a or the second tension applying roller 132b moves in a direction substantially orthogonal to the conveyance direction of the long sheet P1. The frictional load on the sheet P1 is reduced, and the tension applied to the long sheet P1 is weakened.

  On the other hand, in the tension applying device 132, by making the load heavy, the frictional load on the long sheet P1 is increased, and the tension applied to the long sheet P1 is strengthened. Therefore, in the tension application device 132, the strength of tension applied to the long sheet P1 being conveyed is configured to be adjustable.

  The paper collection device 140 includes a shaft 141 that is rotationally driven, and rolls around the shaft 141 the long paper P1 discharged from the image forming apparatus 1A and collects it.

  The sheet feeding device 130 may be provided in the image forming apparatus 1A or may be provided in the sheet feeding device 120. Also, it may be configured as an independent device.

  Next, the configuration of the image forming apparatus 1A will be described with reference to FIG. As illustrated in FIG. 1, the image forming apparatus 1A includes a document reading unit 10, an image forming unit 11, a sheet conveyance unit 2, and a fixing unit 3.

  The document reading unit 10 scans and exposes an image of a document by an optical system of a scanning exposure apparatus, reads the reflected light by a line image sensor, and thereby obtains an image signal. The image forming apparatus 1A may be configured such that an automatic document feeder (not shown) for feeding a document is provided on the upper side.

  The image forming unit 11 is an example of an image forming unit, and forms an image forming unit 11Y that forms an image of yellow (Y), an image forming unit 11M that forms an image of magenta (M), and an image of cyan (C). And an image forming unit 11BK that forms an image of black (BK).

  The image forming unit 11Y includes a photosensitive drum Y and a charging unit 12Y disposed around the photosensitive drum Y, an optical writing unit 13Y, a developing device 14Y, and a drum cleaner 15Y. Similarly, the image forming units 11M, 11C, and 11BK include photosensitive drums M, C, and BK, and charging units 12M, 12C, and 12BK disposed around them, optical writing units 13M, 13C, and 13BK, and developing devices 14M and 14M, respectively. 14C, 14BK and drum cleaners 15M, 15C, 15BK.

  The surface of the photosensitive drum Y is uniformly charged by the charging unit 12Y, and a latent image is formed on the photosensitive drum Y by the scanning exposure by the optical writing unit 13Y. Further, the developing device 14Y develops the latent image on the photosensitive drum Y by developing with toner. Thereby, an image (toner image) of a predetermined color corresponding to yellow is formed on the photosensitive drum Y.

  Similarly, the surface of the photosensitive drum M is uniformly charged by the charging unit 12M, and a latent image is formed on the photosensitive drum M by the scanning exposure by the optical writing unit 13M. Further, the developing device 14M develops the latent image on the photosensitive drum M by developing with toner. As a result, on the photosensitive drum M, a toner image of a predetermined color corresponding to magenta is formed.

  The surface of the photosensitive drum C is uniformly charged by the charging unit 12C, and a latent image is formed on the photosensitive drum C by scanning exposure by the optical writing unit 13C. Further, the developing device 14C develops the latent image on the photosensitive drum C by developing with toner. As a result, a toner image of a predetermined color corresponding to cyan is formed on the photosensitive drum C.

  The surface of the photosensitive drum BK is uniformly charged by the charging unit 12BK, and a latent image is formed on the photosensitive drum BK by scanning exposure by the optical writing unit 13BK. Further, the developing device 14BK develops the latent image on the photosensitive drum BK by developing with toner. Thus, a toner image of a predetermined color corresponding to black is formed on the photosensitive drum BK.

  In the image formed on the photosensitive drums Y, M, C, and BK, the driving roller around which the intermediate transfer belt 16, which is a belt-like intermediate transfer member, is wound is rotationally driven, and the intermediate transfer belt 16 is in the arrow direction. By being driven, they are sequentially transferred to predetermined positions on the intermediate transfer belt 16 by the primary transfer rollers 17Y, 17M, 17C and 17BK.

  The image of each color transferred onto the intermediate transfer belt 16 is transferred by the secondary transfer unit 18 to the sheet P transported by the sheet transport unit 2 at a predetermined timing. The secondary transfer portion 18 is an example of a transfer unit, and the secondary transfer roller 18a is disposed in pressure contact with the intermediate transfer belt 16 to form a transfer nip portion 19, and the secondary transfer roller 18a and the intermediate transfer belt 16 The image is transferred onto the sheet P while being conveyed by being rotationally driven at a constant speed.

  In the secondary transfer portion 18, in order to transfer the toner image to the sheet P, a positive voltage is applied from the back side of the sheet P by the secondary transfer roller 18a. As a result, the sheet P having passed through the secondary transfer portion 18 is charged to the negative side on the image forming surface side to which the toner is transferred, and to the positive side on the back side.

  The sheet conveyance unit 2 includes a plurality of sheet feeding trays 21 in the present embodiment in which sheets P are stored, and a sheet feeding unit 21 a that feeds sheets P stored in the sheet feeding tray 21. Further, the sheet conveyance unit 2 includes a main conveyance path 23 in which the sheet P fed from the sheet feeding tray 21 is conveyed, and a reverse conveyance path 24 in which the sheet P is reversed.

  The main transport path 23 constitutes a transport path from the paper feed tray 21 and the paper feed port 22 to the paper discharge port 25. The conveyance path from the paper feed port 22 merges with the main conveyance path 23 on the upstream side of the joining point of the main conveyance path 23 and the reverse conveyance path 24. In the image forming system 110 shown in FIG. 2, the sheet feeding device 120 and the sheet feeding device 130 are connected to the sheet feeding port 22, and the sheet collecting device 140 is connected to the sheet discharging port 25.

  The sheet conveyance unit 2 corrects an inclination of the sheet P called a skew with respect to the sheet P conveyed on the main conveyance path 23 and a registration roller 26 that corrects the deviation of the position of the sheet P in the width direction orthogonal to the conveyance direction. Equipped with The sheet conveyance unit 2 also includes a loop roller 27 that abuts the sheet against the registration roller 26.

  The registration roller 26 is configured by a pair of rollers facing each other across the sheet P conveyed in the main conveyance path 23, has an axis orthogonal to the conveyance direction of the sheet P, and rotates along the conveyance direction of the sheet P Do.

  The loop roller 27 is configured by a pair of rollers facing each other across the sheet P conveyed in the main conveyance path 23, and is provided on the upstream side of the registration roller 26 with respect to the conveyance direction of the sheet P. The loop roller 27 has an axis orthogonal to the conveyance direction of the sheet P, and conveys the sheet P by rotating along the conveyance direction of the sheet P.

  In a state where the registration roller 26 is stopped, the sheet P is conveyed by the loop roller 27, and the leading end of the sheet P is abutted against the nip portion 26a formed by the contact portions of the pair of rollers. By conveying the sheet P until it is in the state, the inclination in the direction along the surface of the sheet P is corrected.

  After the inclination of the sheet P is corrected, the registration roller 26 is rotationally driven along the conveyance direction of the sheet P, whereby the sheet P is nipped and conveyed. Further, by moving the registration roller 26 in the width direction of the sheet P orthogonal to the conveyance direction of the sheet P, the position in the width direction of the sheet P is corrected. As described above, a series of sheet position correction operations for correcting the deviation of the position in the width direction while conveying the sheet P is referred to as resist oscillation.

  The reverse conveyance path 24 branches from the main conveyance path 23 at the downstream side of the fixing unit 3, and is provided with a switching gate 23 a at a branch point of the main conveyance path 23 and the reverse conveyance path 24. The reverse conveyance path 24 includes a first reverse conveyance path 24 a branched from the main conveyance path 23 and extending substantially horizontally below the main conveyance path 23. In the first reverse conveyance path 24a, the conveyance direction of the sheet P is reversed from the direction of arrow D1 to the direction of arrow D2.

  The reverse conveyance path 24 branches upward from the first reverse conveyance path 24 a in the conveyance direction indicated by the arrow D 2 and bends in a substantially U shape from the second reverse conveyance path 24 b and the second reverse conveyance path 24 b. , And a third reverse transport path 24c extending along the first reverse transport path 24a. Furthermore, the reverse conveyance path 24 includes a fourth reverse conveyance path 24 d that is bent in a substantially U shape from the third reverse conveyance path 24 c and merges with the main conveyance path 23.

  In the image forming apparatus 1A, the sheet P conveyed on the main conveyance path 23 and having passed through the transfer nip portion 19 and the fixing portion 3 forms an image on the surface facing upward. When forming an image on both sides of the sheet P, the sheet P having the image formed on one side facing upward is transported from the main transport path 23 to the first reverse transport path 24 a of the reverse transport path 24. , The image forming surface faces downward.

  The sheet P transported to the first reverse transport path 24 a is transported from the second reverse transport path 24 b to the third reverse transport path 24 c so that the image forming surface faces upward. Then, the sheet P conveyed to the third reverse conveyance path 24 c is conveyed from the fourth reverse conveyance path 24 d to the main conveyance path 23 so that the image forming surface faces downward. As a result, the sheet P is turned upside down, and an image can be formed on the other side facing upward.

  The fixing unit 3 is an example of a fixing unit, and performs a fixing process for fixing the image on the sheet P on which the image is transferred. The fixing unit 3 includes a fixing roller 31 and a fixing roller 32 which are rotationally driven as a pair of fixing conveyance members disposed in pressure contact with each other. In the fixing unit 3, a fixing nip portion 33 is formed by pressing the fixing roller 31 and the fixing roller 32.

  The fixing unit 3 further includes a fixing heater 34 that heats the fixing roller 31 as a heating unit that heats the fixing member. The fixing heater 34 is turned on by energization and, for example, a halogen lamp can be used. The fixing unit 3 conveys the sheet P by rotationally driving the fixing roller 31 and the fixing roller 32, and performs pressure fixing by the pair of fixing rollers 31 and 32, and heat fixing by the fixing heater 34. Is fixed on the sheet P.

<Example of Control Function of Image Forming Apparatus and Image Forming System According to Embodiment>
FIG. 5 is a functional block diagram showing an example of control functions of the image forming apparatus and the image forming system of the present embodiment. Here, in FIG. 5, the control function of maintaining the tension of the long paper P1 in the operation of forming the image on the long paper P1 will be described.

  The image forming apparatus 1A includes a control unit 100 that performs a series of control of feeding a sheet such as a long sheet P1, forming an image, and discharging the sheet. The control unit 100 is an example of a control unit, and includes a microprocessor called a CPU and an MPU, and memories such as a RAM and a ROM as storage units.

  The image forming apparatus 1A also includes a sheet information acquisition unit 101 that acquires sheet information such as the sheet type. The sheet information acquisition unit 101 is an example of a sheet information acquisition unit, and includes an operation unit 101 a and the like as an operation unit that selects the basis weight, sheet type, size, etc. of the sheet P.

  The operation of forming an image on a long sheet P1 by the image forming apparatus 1A will be described. The control unit 100 forms an image based on image data acquired from a document by the document reading unit 10 or image data acquired from the outside. While controlling the unit 11, the sheet conveyance unit 2 and the transfer motor 18M for conveying the long sheet P1 by the secondary transfer unit 18 are controlled to transfer the toner image to the long sheet P1. Further, the control unit 100 controls the fixing heater 34 and the fixing motor 30M for conveying the long sheet P1 by the fixing unit 3 and fixes the toner image on the sheet P.

  The control unit 100 detects the tension of the long paper P1 from the state of electricity flowing to the fixing motor 30M driving the fixing roller 31 etc., and controls the tension applying device 132 based on the state of electricity flowing to the fixing motor 30M. The load applied to the long sheet P1 is controlled so that the tension of the long sheet P1 falls within a predetermined range.

  That is, the load applied to the fixing roller 31 rotationally driven by the fixing motor 30M changes according to the level of the tension of the long sheet P1, and the state of electricity flowing through the fixing motor 30M changes.

  When the tension of the long paper P1 is high, the load applied to the fixing roller 31 rotationally driven by the fixing motor 30M increases, and the state of electricity flowing to the fixing motor 30M changes, for example, the current flowing to the fixing motor 30M The value is higher. On the other hand, when the tension of the long paper P1 is low, the load applied to the fixing roller 31 is reduced, and the current value flowing to the fixing motor 30M is reduced.

  Therefore, when the tension of the long paper P1 is in the appropriate range, the control unit 100 defines the range of the current value flowing to the fixing motor 30M as the appropriate tension information.

  Further, based on the value of the current flowing through the fixing motor 30M, the control unit 100 sets control information of the tension applying device 132 for setting the tension of the long sheet P1 to an appropriate range based on the appropriate tension information. The control information is composed of a program executed by the control unit 100, an operation table for obtaining the operation of the tension applying device 132 from the current value flowing to the fixing motor 30M, and the like.

<Operation Example of Image Forming Apparatus and Image Forming System According to Embodiment>
FIG. 6 is a flow chart showing an example of the operation of the image forming apparatus and the image forming system of the present embodiment. Referring to the respective drawings, the operation of the image forming apparatus and the image forming system of the present embodiment will be described below. explain.

  The control unit 100 controls the fixing motor 30M and the transfer motor 18M such that the linear speed of the secondary transfer roller 18a of the secondary transfer unit 18 and the linear speed of the fixing roller 31 of the fixing unit 3 are substantially the same. So that the conveyance speed of the long paper P1 is substantially the same in the secondary transfer unit 18 and the fixing unit 3

  In the operation of forming an image on the long paper P1, the control unit 100 measures the value of the current flowing through the fixing motor 30M in step SA1 of FIG. In step SA2 of FIG. 6, the control unit 100 determines whether the value of the current flowing through the fixing motor 30M is in the range defined by the appropriate tension information, that is, whether the tension of the long paper P1 is appropriate.

  If the controller 100 determines that the value of the current flowing through the fixing motor 30M is not within the range defined by the appropriate tension information, that is, the tension of the long paper P1 is not appropriate, the fixing motor 30M is selected in step SA3 of FIG. It is determined whether the current value flowing in the current exceeds or falls below the range defined by the appropriate tension information.

  When the control unit 100 determines that the current value flowing to the fixing motor 30M exceeds the range defined by the appropriate tension information, that is, the tension of the long paper P1 is higher than the appropriate range, the process in step SA4 of FIG. The tension application device 132 is controlled based on the value of the current flowing to the fixing motor 30M to reduce the load applied to the long paper P1 so that the tension of the long paper P1 is in the appropriate range.

  On the other hand, when the control unit 100 determines that the current value flowing to the fixing motor 30M falls below the range defined by the appropriate tension information, that is, the tension of the long paper P1 is lower than the appropriate range, FIG. In step SA5, the tension application device 132 is controlled based on the value of the current flowing through the fixing motor 30M to strengthen the load applied to the long sheet P1 so that the tension of the long sheet P1 falls within the appropriate range.

  In the configuration for controlling the tension application device 132 shown in FIG. 3, the control unit 100 causes the fixing motor 30M to move the relative movement amount of the first tension application roller 132a and the second tension application roller 132b as control information. It is set according to the flowing current value.

  When it is determined that the current value flowing to the fixing motor 30M exceeds the range defined by the appropriate tension information, the control unit 100 controls the roller position moving device 133 to set according to the current value flowing to the fixing motor 30M. The first tension applying roller 132a and the second tension applying roller 132b are relatively moved in the direction in which the distance between them approaches each other by the moved amount.

  As a result, the amount of friction L1 of the long paper P1 with respect to the first tension application roller 132a and the second tension application roller 132b is reduced, so that the frictional load on the long paper P1 flows to the fixing motor 30M. And the tension applied to the long paper P1 is weakened.

  When the controller 100 determines that the current value flowing to the fixing motor 30M falls below the range defined by the appropriate tension information, the control unit 100 controls the roller position moving device 133 to set according to the current value flowing to the fixing motor 30M. The first tension applying roller 132a and the second tension applying roller 132b are relatively moved in the direction in which the distance between the first tension applying roller 132a and the second tension applying roller 132b is increased.

  As a result, by increasing the winding amount L2 of the long paper P1 with respect to the first tension application roller 132a and the second tension application roller 132b, the frictional load for the long paper P1 is the current value flowing to the fixing motor 30M. And the tension applied to the long paper P1 is intensified.

  In the configuration for controlling the tension application device 132 shown in FIG. 4, the control unit 100 controls the switching between the rotation state and the stop state of the first tension application roller 132 a and the second tension application roller 132 b as control information. It is set according to the current value flowing to 30M.

  If the control unit 100 determines that the value of the current flowing through the fixing motor 30M exceeds the range defined by the appropriate tension information, the control unit 100 controls the braking device 134 to apply the first tension application roller 132a and the second tension application. The roller 132b is switched to the rotation state. As a result, the friction load on the long paper P1 is reduced, and the tension applied to the long paper P1 is weakened.

  If the control unit 100 determines that the current value flowing to the fixing motor 30M falls below the range defined by the appropriate tension information, it controls the braking device 134 to apply the first tension application roller 132a and the second tension application. The roller 132b is switched to the stop state. As a result, the frictional load on the long paper P1 is increased, and the tension applied to the long paper P1 is intensified.

<Example of Effects of Image Forming Apparatus and Image Forming System According to Embodiment>
In the configuration in which the long sheet P1 is transported to form an image, the long sheet is transported in a tensioned state, so the long sheet is bent as a configuration for detecting the tension of the long sheet. It is not possible to use a sensor that detects the displacement of the position due to the situation.

  Further, the sheet feeding device 120 is provided with a guide member for guiding the long sheet P1 to the sheet feeding device 130, and the long sheet P1 is conveyed in a state of being in contact with the guide member. The tension during transport is not constant and always fluctuates.

  In the configuration in which the tension of the long paper is manually adjusted, since the tension can not be adjusted during conveyance of the long paper P1, the fluctuation of the tension during conveyance can not be followed, and the tension of the long paper P1 is It is difficult to adjust the to an appropriate value.

  Furthermore, if the linear velocity of the fixing unit 3 is adjusted to adjust the tension of the long paper P1, a difference occurs in the linear velocity between the secondary transfer unit 18 and the fixing unit 3, and both the linear velocity difference and the tension are generated. Becomes very difficult to control. In particular, if the linear velocity difference between the secondary transfer portion 18 and the fixing portion 3 is dispersed, the long paper run-off and color registration become significantly unstable.

  On the other hand, in the image forming apparatus 1A and the image forming system 110 of the present embodiment, the tension of the long paper P1 is detected from the state of electricity flowing to the fixing motor 30M. The load applied to the fixing roller 31 changes due to the fluctuation of the tension of the long paper P1, and the state of electricity flowing to the fixing motor 30M changes.

  Therefore, the tension of the long paper P1 can be detected without using a sensor for detecting the position of the long paper P1, and even if the tension fluctuates with the conveyance of the long paper P1, the fluctuated tension can be detected. can do.

  Then, based on the detected tension, the tension application device 132 controls the friction load applied to the long paper P1 so that the tension of the long paper P1 is an appropriate value without changing the linear velocity of the fixing unit 3. Can be controlled.

  Thereby, in the present embodiment, since it is not necessary to manually adjust the tension of the long paper P1, it is possible to reduce the time and effort of the adjustment. In addition, it is possible to reduce the reduction in quality and the down time, which is referred to as waste paper, due to the erroneous adjustment of the tension.

  Furthermore, in the present embodiment, since the linear transfer speeds of the secondary transfer unit 18 and the fixing unit 3 can be kept substantially the same without changing the linear speed of the fixing unit 3, the meandering of the long sheet is suppressed. , Color registration can be stabilized.

  When the tension of the long sheet P1 is high between the secondary transfer portion 18 and the fixing portion 3, the color registration becomes unstable although the influence on the sheet winding is small. On the other hand, when the tension of the long paper P1 is low, the influence on the color registration is small, but the paper weight becomes unstable.

  In the present embodiment, since the tension of the long paper P1 can be controlled to a range that satisfies both of these conditions, meandering of the long paper can be suppressed and color registration can be stabilized.

<Modified Example of Image Forming Apparatus and Image Forming System According to Embodiment>
In the above example, the current value flowing to the fixing motor 30M is detected as the appropriate tension information. However, as the state of electricity flowing to the fixing motor 30M, a voltage value and a resistance value may be detected.

  FIG. 7 is an explanatory view showing an outline of a proper range of tension of the long paper. The proper range of the tension of the long paper P1 varies depending on the paper type, basis weight and the like, and the proper range of the current value flowing to the fixing motor 30M also varies depending on the paper type, basis weight and the like.

The range of appropriate tension differs between a certain paper type, long paper Pa having a basis weight and the other paper types, long paper Pb and Pc having a basis weight, for example, a range Ta ₁ of appropriate tension in long paper Pa On the other hand, the appropriate tension range Tb ₁ of the long paper Pb is high. Further, with respect to the range Ta ₁ proper tension in the long paper Pa, a low range Tc ₁ proper tension in the long paper Pc.

As a result, the range Ta _{2 of} tension determined to be unsuitable for color registration and the range Tc _{2 of} tension determined to be unsuitable for paper meandering differ depending on the paper type and basis weight of the long paper. .

For this reason, even if the tension range Ta ₂ is determined to be inappropriate for long paper Pa, color registration may be an appropriate tension range Tb ₁ for long paper Pb. The tension needs to be adjusted according to the basis weight and the like.

  Therefore, the control unit 100 defines appropriate tension information for each sheet type, basis weight, and the like of the long sheet P1 specified by the sheet information. Further, in the control unit 100, the operation of the tension applying device 132 based on the current value flowing to the fixing motor 30M and the sheet information of the long sheet P1 is set as control information.

  In the operation of forming an image on the long sheet P1, the sheet information such as the sheet type and basis weight of the long sheet P1 is set by the operation at the operation unit 101a, whereby the appropriate tension information corresponding to the sheet information is set. Be done.

  In this example, by setting the paper type, basis weight, and the like of the long paper P1, the appropriate tension information according to the type of the long paper P1 is set. On the other hand, the user or the like may be allowed to select the appropriate tension information by the operation at the operation unit 101a, and the user may select the appropriate tension information according to the type of the long paper P1 to be used.

  If the control unit 100 determines that the current value flowing to the fixing motor 30M exceeds the range defined by the appropriate tension information set based on the sheet information, the control unit 100 determines the tension applying device 132 based on the current value flowing to the fixing motor 30M. The load on the long paper P1 is reduced so that the tension of the long paper P1 falls within the appropriate range.

  In addition, when the control unit 100 determines that the current value flowing to the fixing motor 30M falls below the range defined by the appropriate tension information set based on the sheet information, the tension applying device based on the current value flowing to the fixing motor 30M By controlling 132, the load applied to the long paper P1 is strengthened so that the tension of the long paper P1 falls within the appropriate range.

  The present invention is applied to an image forming apparatus including an image forming apparatus for transferring and fixing a toner image on a long sheet to form an image, and an image forming system including an apparatus for feeding and collecting the long sheet to the image forming apparatus. Be done.

  1A: image forming apparatus 2: sheet conveying unit 3: transfer unit 100: control unit 110: image forming system 120: sheet supplying apparatus 130: 130 Paper feeding device 132: tension applying device 140: paper collecting device

Claims (10)

An image forming unit having a transfer unit for transferring toner onto a long sheet of paper and forming an image on the long sheet;
Fixing means for fixing the image on the long sheet on which the image is formed by the image forming means;
A fixing and conveying unit that conveys a long sheet by the fixing unit;
By driving the fixing and conveying means, electricity flowing to the fixing and conveying means is detected, and based on the change in the state of electricity according to the load applied to the fixing and conveying means, the image forming means is moved relative to the long paper conveyance path. and control means for controlling the frictional load applied to the long paper in the tension applying means provided on the upstream side,
The image forming apparatus , wherein the fixing and conveying unit is a motor for driving a fixing and conveying member that conveys the long sheet in contact with the long sheet . The control means sets the appropriate range of tension of the long paper as the proper tension information, and based on the state of electricity flowing to the fixing and conveying means, the tension of the long paper is proper based on the proper tension information. 2. The image forming apparatus according to claim 1, wherein control information to be set as a range is set. Before SL control means condition the current value of the electricity flowing to the motor that is driven to rotate, detected from the voltage value or resistance value, based on the current value of the electricity flowing to the motor, the voltage value, or resistance value, the The image forming apparatus according to claim 1, wherein the friction load applied to the long sheet is controlled by a tension applying unit. The control means is configured to set appropriate tension information corresponding to sheet information for specifying a type of long sheet, and to select appropriate tension information by selecting the sheet information. Or, the image forming apparatus according to claim 3. The image forming apparatus according to any one of claims 1 to 3, wherein the control means selects the appropriate tension information set corresponding to the sheet information specifying the long sheet type. apparatus. The above-mentioned tension application means controls the friction load applied to the long paper by changing the winding amount of the long paper around the tension application roller rotating in contact with the long paper. An image forming apparatus according to any one of claims 5 to 10. The said tension application means controls the friction load applied to the long sheet by switching the rotation state and the stop state of the tension application roller which is rotated following the conveyance of the long sheet. The image forming apparatus according to any one of claims 6 to 10. The tension applying means applies a load in the rotation direction of the tension applying roller which rotates following the conveyance of the long paper, and includes a resistance applying means which makes the load variable, whereby the friction load applied to the long paper is obtained. The image forming apparatus according to any one of claims 1 to 5, wherein the control is performed. Said tensioning means, by a movable state tensioning roller rotated by the conveyance of the long paper, a load is applied to a linear direction orthogonal to the transport direction of the long paper, long The image forming apparatus according to any one of claims 1 to 5, which controls a friction load applied to a sheet of paper. An image forming apparatus,
A sheet feeding device for storing a long sheet fed to the image forming apparatus;
A sheet feeding device for feeding a long sheet from the sheet feeding device to the image forming apparatus;
A sheet collection device for storing a long sheet on which an image is formed by the image forming apparatus;
The image forming apparatus is
An image forming unit having a transfer unit for transferring toner onto a long sheet of paper and forming an image on the long sheet;
Fixing means for fixing the image on the long sheet on which the image is formed by the image forming means;
A fixing and conveying unit that conveys a long sheet by the fixing unit;
By driving the fixing and conveying means, electricity flowing to the fixing and conveying means is detected, and based on a change in the state of electricity according to the load applied to the fixing and conveying means, the tension applying means provided in the sheet feeding device And control means for controlling the frictional load applied to the sheet ,
The image forming system according to claim 1, wherein the fixing and conveying unit is a motor that drives a fixing and conveying member that conveys the long sheet in contact with the long sheet .

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