JP2005274623A - Image forming apparatus for continuous paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for continuous paper, which allows a transfer roller to be cleaned regardless of whether or not a paper exists. <P>SOLUTION: A transfer roller 30 can be moved to three positions of a transfer position (A in Figure) for image transfer, a cleaning position (B in Figure) for cleaning the transfer roller by a cleaning roller 32, and a retreat position (C in Figure) for non-transfer and non-cleaning, and two guide rollers 36 for guiding a continuous paper P to the transfer roller 30 can be moved to two positions of a guide position (A in Figure) for guiding the continuous paper P to the transfer roller 30 and a guide retreat position (C in Figure) for non-guiding of the continuous paper, so that the transfer roller 30 can be cleaned regardless of the existence of the continuous paper P between the transfer roller and a photosensitive drum 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus for continuous paper, and more particularly to an image forming apparatus for continuous paper that forms an image on continuous paper using an electrophotographic system.

  In an image forming apparatus using an electrophotographic system such as a copying machine or a printer, a latent image is formed by forming uniform charges on an image carrier such as a photosensitive drum and using light such as laser light modulated by an image signal. After forming the electrostatic latent image, the electrostatic latent image is developed with charged toner to form a visualized toner image. Then, the toner image is transferred to a sheet or the like and fixed, thereby forming an image on the sheet.

  As a transfer method in an image forming apparatus using such an electrophotographic method, a corona transfer method in which a toner image is electrostatically transferred onto a sheet using corona discharge or the like, an electrostatic transfer method using an electrostatic force, heating and There have been proposed a thermal transfer method using adhesion force under pressure particle melting by pressure, a pressure transfer method (transfer roller method) using adhesion force or adhesion force under pressure, and the like.

  In high-speed continuous printers, the corona transfer method has been generally used among the various transfer methods described above. However, use of poor paper, thin paper, etc., poor transfer due to paper flaws when multiple printers are connected and continuous printing, transfer failure of stepped media with credit cards etc. pasted on paper, etc. As a countermeasure for these, a transfer roller system is desired.

  The transfer roller method is a technology generally used in a cut paper printer, but there are several technical problems in adopting it in a high-speed continuous paper printer, and the transfer roller cleaning is an important one. .

  In the transfer roller system, the transfer roller is always in contact with the photoconductor during transfer, and an electric charge for attracting toner on the photoconductor is applied. For this reason, if there is a part with no paper (to cope with various paper widths), the toner on the drum in the part without paper moves onto the transfer roller, and then the paper becomes wider when the paper width becomes wider. There is a problem that the back surface of the toner is soiled with toner on the transfer roller.

  The conventional cleaning of the transfer roller is simplified due to the downsizing of the apparatus, and it is not necessary to provide a cleaning mechanism from the viewpoint of cost reduction. When the transfer roller is in contact with the photosensitive drum during non-printing (between sheets) Cleaning is performed in which a bias having a polarity opposite to that of the toner is applied to return the toner on the transfer roller to the photosensitive drum.

  As other methods for cleaning the transfer roller, for example, techniques described in Patent Document 1 and Patent Document 2 have been proposed.

  In the technique described in Patent Document 1, it is proposed that the presence or absence of a sheet is detected, the transfer roller and the photosensitive drum are separated from each other when there is no sheet, and cleaning is performed by bringing the transfer roller and the cleaning member into contact at that position. Yes.

In the technique described in Patent Document 2, it has been proposed that the photosensitive roller on the transfer roller is irradiated with light to be changed to conductivity, and the transfer roller is cleaned with the recovery roller.
JP-A-8-314297 Japanese Patent Laid-Open No. 6-186812

  However, the method of cleaning the transfer roller by returning the toner to the photosensitive drum has a problem that the high-speed continuous paper printer in which paper always exists between the transfer roller and the photosensitive drum cannot perform cleaning.

  Further, the technique described in Patent Document 1 has a problem that it cannot be used for a high-speed continuous paper printer because cleaning can be performed only when there is no paper.

  Furthermore, the technique described in Patent Document 2 has a problem that it is necessary to use a photoconductive toner.

  The present invention has been made to solve the above problem, and an object thereof is to provide a continuous paper image forming apparatus capable of cleaning a transfer roller regardless of the presence or absence of paper.

  In order to achieve the above object, the invention described in claim 1 includes a transfer roller for transferring an image to continuous paper, a guide roller for guiding the continuous paper to the transfer roller when the image is transferred by the transfer roller, An image forming apparatus for continuous paper that forms an image on continuous paper using an electrophotographic method, wherein the transfer roller transfers an image by the transfer roller. A transfer position for cleaning, a cleaning position for cleaning by the cleaning roller, and a retracted position for non-transfer and non-cleaning, and a guide position for the guide roller to guide continuous paper, and a continuous position There are two guide retracting positions for non-guide the paper.

  According to the first aspect of the present invention, the image can be transferred onto the continuous paper by setting the position of the transfer roller as the transfer position and the position of the guide roller as the guide position.

  Further, by setting the position of the transfer roller as the cleaning position and the position of the guide roller as the guide position, for example, the transfer roller can be cleaned by the cleaning roller during continuous paper conveyance between pages.

  In addition, the transfer roller position is set as the cleaning position, and the guide roller position is set as the guide retraction position. The transfer roller can be cleaned.

  Further, by setting the position of the transfer roller as the retracted position and the position of the guide roller as the guide retracted position, it is possible to perform continuous paper conveyance without cleaning.

Therefore, the transfer roller can be cleaned regardless of the presence or absence of paper by providing three positions for the transfer roller and two positions for the guide roller. The invention according to claim 2 uses an electrophotographic system. An image forming apparatus for continuous paper that forms an image on continuous paper, comprising: a cleaning mechanism having a cleaning roller for cleaning a transfer roller for transferring an image to continuous paper; and the transfer roller for transferring an image A transfer mechanism that moves the transfer roller to three positions, a transfer position, a cleaning position for cleaning the transfer roller, and a retracted position for non-transfer and non-cleaning, and guides continuous paper conveyed through the transfer mechanism A guide position with a guide roller for guiding continuous paper and a guide retracting position for non-guided continuous paper And a guide mechanism for moving the guide roller at two positions.

  According to the second aspect of the present invention, the transfer mechanism moves the transfer roller position to the transfer position, the cleaning position, and the retracted position, and the guide mechanism moves the guide roller position to the guide position and the guide retracted position. To do.

  By providing the transfer mechanism and the guide mechanism in this manner, the transfer roller can be moved to three positions and the guide roller can be moved to two positions as in the first aspect of the invention. Therefore, by providing three positions of the transfer roller and two positions of the guide roller, the transfer roller can be cleaned regardless of the presence or absence of paper.

  For example, as described in the third aspect of the present invention, by further providing a control means for controlling the cleaning mechanism, the transfer mechanism, and the guide mechanism, various operations as described above can be realized by the control means. .

  Further, at this time, as in the invention described in claim 4, the control means performs cleaning of the transfer roller by the cleaning roller at the time of non-printing (for example, between pages or at initialization of the apparatus) regardless of the presence or absence of continuous paper. The cleaning mechanism, the transfer mechanism, and the guide mechanism may be controlled as described above, or the cleaning time may be set according to the printing amount of the continuous paper as in the invention described in claim 5, The cleaning mechanism, the transfer mechanism, and the guide mechanism may be controlled.

  Further, as in the invention described in claim 6, the control means may control the cleaning mechanism, the transfer mechanism, and the guide mechanism so that the transfer roller and the cleaning roller are always in contact with each other during printing. At this time, the control means determines the current value to be applied to the transfer roller and the cleaning roller so that the sum of the current values flowing through the transfer roller and the cleaning roller becomes the transfer current value. By controlling the current, the transfer roller can be simultaneously cleaned during image transfer without affecting the image transfer onto the continuous paper.

  The cleaning roller can be made of a photosensitive material that is charged with a polarity opposite to that of the toner.

  As described above, according to the present invention, the cleaning roller for cleaning the transfer roller is provided, the transfer roller is provided with the transfer position, the cleaning position, and the retracted position, and the guide roller guides the continuous paper to the transfer roller. By providing two positions, a guide position and a guide retract position, there is an effect that the transfer roller can be cleaned regardless of the presence or absence of paper.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to a continuous paper image forming apparatus capable of color printing.

  FIG. 1 is a diagram showing an overall configuration of an image forming apparatus for continuous paper according to an embodiment of the present invention.

  The continuous paper image forming apparatus 10 according to the embodiment of the present invention forms an image corresponding to each color of C (cyan), M (magenta), Y (yellow), and K (black) on the continuous paper P4. The image forming units 12C, 12M, 12Y, and 12K are included. Since the image forming units 12C, 12M, 12Y, and 12K have the same configuration for each color, the reference numerals (C, M, Y, and K) corresponding to the respective colors are shown in FIG. Unless otherwise distinguished, reference numerals corresponding to the respective colors are omitted.

  Each image forming unit 12 has a photosensitive drum 14 rotatably supported on the apparatus main body frame in the drawing, and around each photosensitive drum 14 is a drum rotating direction (clockwise direction in FIG. 1). ), The cleaner unit 16, the charger 18, the exposure unit 20, the developing unit 22, and the transfer unit 24 are arranged in this order.

  That is, after the toner remaining on the photosensitive drum 14 is removed by the cleaner unit 16, the toner is charged by the charger 18, and light is irradiated on the surface of the photosensitive drum 14 by the exposure unit 20 to form a latent image. The latent image formed by the exposure unit 20 is developed by the developing unit 22 to form a toner image, and is transferred onto the continuous paper P by the transfer roller 30 included in the transfer unit 24. At this time, a current is applied to the transfer roller 30 in a direction in which the toner is attracted to the transfer roller 30 toward the photosensitive drum 14, and the toner is easily transferred to the continuous paper P.

  Further, by repeating the above-described operation by each image forming unit 12, the images of the respective colors are superimposed on the continuous paper P and are fixed by the fixing unit 26 provided in the continuous paper transport direction, so that a color image is obtained. Is formed on the continuous paper P.

  By the way, the continuous paper image forming apparatus 10 according to the present exemplary embodiment includes a cleaning mechanism for cleaning the transfer roller 30 in the transfer unit 24.

  As shown in FIG. 2B, the cleaning mechanism has a cleaning roller 32 for cleaning the toner remaining on the transfer roller 30 in contact with the transfer roller 30, and the cleaning roller 32 collects the toner from the transfer roller 30. The toner is removed by the cleaning blade 34.

  The cleaning roller 32 is made of a photosensitive material that is charged with a polarity opposite to that of the toner. For example, the cleaning roller 32 can be made of a resin-based material such as amorphous resin or a fluorine-based resin such as a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (PFA). The transfer roller 30 is cleaned by attracting toner remaining on the transfer roller 30.

  In this embodiment, the transfer roller 30 transfers an image to the cleaning roller 32 (FIG. 2A), and the cleaning position for cleaning the transfer roller by the cleaning roller 32 (FIG. 2). 2 (B)) and a retracted position (FIG. 2C) for non-transfer and non-cleaning.

  Further, the continuous paper image forming apparatus 10 according to the present embodiment has two guide rollers 36 for guiding the continuous paper P to the transfer roller 30, and the guide roller 36 is connected to the transfer roller 30 by the continuous paper. It is possible to move to two positions: a guide position for guiding P (FIGS. 2A and 2B) and a guide retraction position for making continuous paper non-guided (FIG. 2C). .

  Here, a transfer roller moving mechanism for moving the transfer roller 30 in the transfer unit 24 to three positions as described above, and a guide roller moving mechanism for moving the guide roller 36 to two positions as described above will be described. To do.

  3 shows positions of the transfer roller 30 and guide roller 36 during printing (transfer position of the transfer roller 30 and guide position of the guide roller 36), and FIG. 4 shows positions when the transfer roller 30 and guide roller 36 are cleaned. FIG. 5 shows the standby position of the transfer roller 30 and the guide roller 36 (the retracted position of the transfer roller 30 and the guide retracted position of the cleaning roller 32). Indicates.

  The transfer unit 24 includes a transfer roller holding member 38 that rotatably supports a transfer roller 30 provided to face the photosensitive drum 14.

  The transfer roller holding member 38 is rotatably supported on the housing 40 of the transfer unit 24 by a rotation shaft 38A, and is rotatable in the direction of arrow A about the rotation shaft 38A. Further, the transfer roller holding member 38 is urged in the direction of arrow B by a spring 42 that is rotatably supported on one end side so that the transfer roller 30 is rotatable and the other end side is locked to the housing 40. .

  At a position facing the transfer roller holding member 38 on the side opposite to the photosensitive drum 14 and a position corresponding to the end of the transfer roller holding member 38 where the spring 42 is locked and the rotation shaft 38A, the housing 40 A cam 44 that is rotatably supported is provided. The cam 44 is an eccentric cam whose center is eccentric. By rotating the cam 44, the transfer roller holding member 38 can rotate in a direction opposite to the bias of the spring 42 in the arrow B direction. That is, the rotation of the cam 44 rotates the transfer roller holding member 38 as shown in FIGS. 3, 4, and 5, whereby the transfer roller 30 moves away from and approaches the photosensitive drum 14. The height of the cam 44 changes according to the rotational position of the cam 44, so that the position of the transfer roller 30 relative to the photosensitive drum 14 can be changed to three positions.

  A cleaning roller 32 is rotatably supported by the housing 40 at a position facing the transfer roller 30 on the opposite side of the photosensitive drum 14.

  On the other hand, guide rollers 36 are provided at positions upstream and downstream of the transfer roller 30 in the paper transport direction.

  The guide roller 36 is rotatably supported by the guide roller holding member 46 so as to guide the continuous paper P to the transfer position.

  The guide roller holding member 46 is provided with a slide groove 46A which is a long hole in a direction orthogonal to the paper transport direction. A boss 40A provided on the housing 40 engages with the slide groove 46A, and the boss 40A. On the other hand, the guide roller holding member 46 is movable in a direction orthogonal to the paper transport direction. The guide roller holding member 46 has one end locked to the other end of the spring 48 locked to the housing 40, and is separated from the photosensitive drum 14 in a direction perpendicular to the paper transport direction. Is biased in the direction.

  A cam 50 rotatably supported by the housing 40 is provided at a position facing the opposite side of the guide roller holding member 46 from the photosensitive drum 14. The cam 50 is an eccentric cam whose center is eccentric, and the guide roller holding member 46 moves in a direction against the bias of the spring 48 by rotating the cam 50. That is, the rotation of the cam 50 moves the guide roller holding member 46 as shown in FIGS. 3, 4, and 5, whereby the guide roller 36 moves away from and approaches the photosensitive drum 14. The height of the cam 50 changes according to the rotation of the cam 50, so that the position of the guide roller 36 relative to the photosensitive drum 14 can be changed to two positions.

  Next, the configuration of the control system for operating the cleaning mechanism when cleaning the transfer roller 30 in the continuous sheet image forming apparatus 10 configured as described above will be described.

  FIG. 6 is a block diagram showing the configuration of a control system for operating the cleaning mechanism of the continuous sheet image forming apparatus 10 according to the embodiment of the present invention.

  The continuous paper image forming apparatus 10 according to the present embodiment includes a control circuit 60 for controlling the cleaning mechanism of the transfer unit 24 as shown in FIG.

  The control circuit 60 is connected to a main control unit 62 for controlling the overall operation of the continuous sheet image forming apparatus 10, and controls to clean the transfer roller 30 in accordance with an instruction from the main control unit 62. As instructions input from the main control unit 62 to the control circuit 60, various instructions such as a print instruction, a cleaning instruction, and a standby instruction are input.

  A transfer roller moving cam rotation motor 64 and a guide roller moving cam rotation motor 66 for changing the position of the transfer roller 30 are connected to the control circuit 60. Each motor is controlled according to an instruction from the main control unit 62. The above-described drive control is performed, and the transfer rollers 30 and the guide roller 36 are controlled to move to the respective positions by rotating the cams 44 and 50 described above.

  Further, a transfer driving circuit 68 is connected to the control circuit 60, and the transfer driving circuit 68 performs drive control when transferring an image onto the continuous paper P, that is, when a print instruction is input from the main control unit 62. Then, an electric current is applied to the transfer roller 30 to transfer the image onto the continuous paper P.

  In addition to this, a cleaning drive circuit 70 is connected to the control circuit 60, and the cleaning drive circuit 70 is driven when the transfer roller 30 is cleaned, that is, when a cleaning instruction is input from the main control unit 62. The transfer roller 30 is cleaned by applying an electric current to the cleaning roller 32 so that the cleaning roller 32 has a polarity opposite to that of the toner.

  Next, the operation of the continuous sheet image forming apparatus 10 configured as described above will be described.

  When a continuous paper P supply is instructed from an operation unit (not shown) of the continuous paper image forming apparatus 10 and the continuous paper P is supplied to the continuous paper image forming apparatus 10, the control circuit 60 includes a guide roller moving cam rotation motor. 66, the position of the cam 50 is controlled to be as shown in FIG. 5, and the guide roller 36 moves as the cam 50 rotates and the guide roller holding member 46 moves away from the photosensitive drum 14. The state is separated from the continuous paper P. Further, the control circuit 60 controls the transfer roller moving cam rotation motor 64 so that the position of the cam 44 becomes the position shown in FIG. 5, and the cam 44 rotates and the transfer roller holding member 38 rotates. The transfer roller 30 enters a state where it does not contact the cleaning roller 32 and the photosensitive drum 14 (retracted state). In this state, the paper is conveyed and the continuous paper P is set.

  FIG. 7 is a flowchart showing an example of the operation flow of the continuous paper image forming apparatus 10 according to the embodiment of the present invention. FIG. 7 shows the flow of operation when the power is turned on with the continuous paper P being supplied as described above.

  When the power is turned on, first, in step 100, the apparatus is initialized. At this time, the transfer roller is simultaneously cleaned. That is, a cleaning instruction is output from the main control unit 62 to the control circuit 60, and the control circuit 60 receives the cleaning instruction to control the rotational drive of the transfer roller moving cam rotation motor 64 so that the position of the cam 44 is as shown in FIG. It is controlled to be a position. As a result, the cam 44 rotates and the transfer roller holding member 38 rotates in the direction of arrow A in FIG. 4 (the direction opposite to the biasing direction of the spring 42), so that the transfer roller 30 comes into contact with the cleaning roller 32. . Then, when the control circuit 60 outputs a drive instruction to the cleaning drive circuit 70, a current is applied to the cleaning roller 32 so as to have a reverse characteristic to that of the toner, and the rotation of the cleaning roller 32 is driven. The roller 30 is cleaned. At this time, if the continuous paper P is not set in the continuous paper image forming apparatus 10, the control circuit 60 controls the guide roller moving cam rotation motor 66 so that the cam 50 is positioned as shown in FIG. The guide roller 36 is separated from the continuous paper P by the cam 50 rotating and the guide roller holding member 46 moving in a direction away from the photosensitive drum 14. Good. As a result, the continuous paper P can be set simultaneously.

  Next, in step 102, it is determined by the main control unit 62 whether or not printing is started. This determination is mainly based on whether or not a print instruction is given from an operation unit (not shown) of the continuous paper image forming apparatus 10 or whether or not a print instruction is input to the continuous paper image forming apparatus 10 from an external computer or the like. The determination is made by the control unit 62, and the process waits until the determination is affirmed and the process proceeds to step 104.

  In step 104, a printing process is performed. That is, a printing instruction is input to the control circuit 60, the control circuit 60 controls the guide roller moving cam rotation motor 66, the position of the cam 50 is controlled to the position shown in FIG. 3, and the cam 50 rotates. The guide roller 36 comes into contact with the continuous paper P as the guide roller holding member 46 moves in a direction approaching the photosensitive drum 14. Further, the control circuit 60 controls the transfer roller moving cam rotation motor 64 so that the position of the cam 44 becomes the position shown in FIG. 3, and the cam 44 rotates to move the transfer roller holding member 38 in the direction of arrow A in FIG. By rotating in the direction in which the spring 42 is urged, the transfer roller 30 comes into contact with the photosensitive drum 14 via the continuous paper P.

  Then, each image forming unit 12 is driven and controlled by the main control unit 62, and the toner remaining on the photosensitive drum 14 is removed by the cleaner unit 16, the photosensitive drum 14 is charged by the charger 18, and the photosensitive drum by the exposure unit 20. 14 is irradiated with light, a latent image is formed on the photosensitive drum 14, a toner image is formed by development by the developing device 22, and an image is formed on the continuous paper P by transfer by the transfer roller 30. . The above-described operation is repeatedly performed by each image forming unit 12, and an image of each image forming unit 12 is transferred onto the continuous paper P to form a color image. Then, the fixing unit 26 fixes the image.

  Subsequently, in step 106, it is determined whether or not a predetermined page has been printed. The determination is made, for example, by determining from the number of pages of print data output from the main control unit 62 to the exposure unit 20, and if the determination is negative, the process proceeds to step 110, and the determination is affirmative. If YES, the process proceeds to step 108, and after the transfer roller is cleaned, the process proceeds to step 110. That is, a cleaning instruction is output from the main control unit 62 to the control circuit 60, and the control circuit 60 receives the cleaning instruction to control the rotational drive of the transfer roller moving cam rotation motor 64 so that the position of the cam 44 is as shown in FIG. It is controlled to be a position. As a result, the cam 44 rotates and the transfer roller holding member 38 rotates in the direction of arrow A in FIG. 4 (the direction opposite to the biasing direction of the spring 42), so that the transfer roller 30 comes into contact with the cleaning roller 32. . Then, when the control circuit 60 outputs a drive instruction to the cleaning drive circuit 70, a current is applied to the cleaning roller 32 so as to have a reverse characteristic to that of the toner, and the rotation of the cleaning roller 32 is driven. The roller 30 is cleaned. The cleaning operation at this time is performed in a non-image forming area between pages, and the guide roller 36 remains at the position at the time of printing. Further, step 106 and step 108 may be omitted.

  Next, at step 110, it is determined by the main control unit 62 whether or not printing is finished. If the determination is negative, the processing returns to step 102 and the above-described processing is repeated until the determination at step 110 is affirmed. .

  If the determination at step 110 is affirmative, the routine proceeds to step 112 where the last portion of the continuous paper P to which the image has been transferred by the transfer roller 30 is fixed by the fixing unit 26 and then printed. For this purpose, the continuous paper P is returned from the position of the fixing unit 26 to the position of the transfer roller 30. At this time, the transfer roller 30 is cleaned. That is, when a cleaning instruction is input to the control circuit 60, the control circuit 60 controls the transfer roller moving cam rotation motor 64, and the position of the cam 44 is controlled to the position shown in FIG. Then, the transfer roller holding member 38 rotates in the direction of arrow A in FIG. 4 (the direction opposite to the biasing direction of the spring 42), so that the transfer roller 30 comes into contact with the cleaning roller 32. Then, when the control circuit 60 outputs a drive instruction to the cleaning drive circuit 70, a current is applied to the cleaning roller 32 so as to have a reverse characteristic to that of the toner, and the rotation of the cleaning roller 32 is driven. The roller 30 is cleaned. In the case where the configuration in which Step 106 and Step 108 are omitted, when the transfer roller 30 is cleaned in Step 112, the control circuit 60 causes the main control unit 62 to print from the previous cleaning (for example, The number of print pages and the like may be acquired, and the time for driving the cleaning roller 32, that is, the cleaning time may be set according to the acquired print amount.

  As described above, when the transfer roller is cleaned in step 112, it is subsequently determined whether or not the power is turned off in step 114. If the determination is negative, the process returns to step 102 and the determination in step 114 is performed. The above-described processing is repeated until the result is affirmed. When the determination in step 114 is affirmed, the operation of the series of continuous sheet image forming apparatus 10 is terminated.

  When only the continuous paper P is transported, the control circuit 60 receives the continuous paper P transport instruction from the main control unit 62 and controls the guide roller moving cam rotation motor 66 so that the position of the cam 50 is determined. The guide roller 36 is separated from the continuous paper P when the cam 50 rotates and the guide roller holding member 46 moves in a direction away from the photosensitive drum 14. Further, the control circuit 60 controls the transfer roller moving cam rotation motor 64 so that the position of the cam 44 is controlled to the position shown in FIG. 5, and the transfer is performed by rotating the cam 44 and rotating the transfer roller holding member 38. The roller 30 comes into contact with the continuous paper P and the cleaning roller 32 so that the continuous paper P is conveyed.

  That is, in the continuous sheet image forming apparatus 10 according to the present embodiment, the cleaning roller 32 is provided so that the transfer roller 30 can be moved to three positions and the guide roller 36 can be moved to two positions. Even when there is continuous paper P between the transfer roller and the photosensitive drum 14 during non-printing, the transfer roller 30 can be cleaned.

  Next, a modification of the continuous paper image forming apparatus according to the embodiment of the present invention will be described. 8 and 9 are diagrams showing the configuration of the transfer unit in the continuous paper image forming apparatus according to the modification. Note that the same parts as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the above embodiment, the transfer roller 30 is not cleaned at the time of printing. However, in the modification, the transfer roller 30 is cleaned at the time of printing. That is, in the modified example, the transfer roller 30 can be always cleaned.

  In the modification, in order to clean the transfer roller 30 at the time of printing, a cleaning roller moving mechanism for bringing the cleaning roller 32 into contact with the transfer roller 30 at the time of printing is provided. As shown, the cleaning roller 32 is brought into contact with the transfer roller 30 during printing.

  Here, the moving mechanism of the cleaning roller 32 will be described.

  As shown in FIGS. 8 and 9, the cleaning roller 32 is rotatably supported by the cleaning roller holding member 72. Similarly to the guide roller holding member 46, the cleaning roller holding member 72 is provided with a slide groove 72A having a long hole in a direction orthogonal to the paper transport direction, and the boss 40B provided in the housing 40 slides. The cleaning roller holding member 72 engages with the groove 72A and can move in a direction perpendicular to the paper conveyance direction with respect to the boss 40B. Further, the cleaning roller holding member 72 has one end locked to the other end of the spring 74 locked to the housing 40, and is separated from the photosensitive drum 14 in a direction perpendicular to the paper transport direction. Is biased in the direction.

  Further, a cam 76 rotatably supported by the housing 40 is provided at a position facing the opposite side of the cleaning roller holding member 72 from the photosensitive drum 14. The cam 76 is an eccentric cam whose center is eccentric, and the cleaning roller holding member 72 moves in a direction opposite to the bias of the spring 74 by rotating the cam 76. That is, the rotation of the cam 76 moves the cleaning roller holding member 72 as shown in FIGS. 8 and 9, thereby moving the cleaning roller 32 away from and closer to the photosensitive drum 14. In addition, the height of the cam 76 changes according to the rotation of the cam 76, so that the cleaning roller 32 can be moved to a contact position with the transfer roller 30 or can be moved to a position away from the transfer roller 30. .

  In the modified example, since the transfer roller 30 and the cleaning roller 32 are in contact with each other at the time of printing, a current i2 applied to the cleaning roller 32 at the time of transfer is transferred via the transfer roller 30 to the photosensitive drum as shown in FIG. 14, the transfer current i changes, and the transfer current i2 is affected by the cleaning current i2.

  Therefore, the transfer current i applied to the photosensitive drum 14 when transferring the image to the continuous paper P is the sum of the cleaning current i2 applied to the cleaning roller 32 and the transfer current i2 applied to the transfer roller 30. And constant current control.

  FIG. 10B shows a case where the power supply voltage v2 is applied to the cleaning roller 32 and the cleaning roller 32, the transfer roller 30, and the photosensitive drum 14 are applied as an electric circuit when the power supply voltage v1 is applied to the transfer roller 30. It is an equivalent circuit. Here, the resistance value of the transfer roller 30 is indicated as R1, the resistance value of the cleaning roller 32 is indicated as R2, and the photosensitive drum 14 is indicated as a capacitor C.

  In the present embodiment, constant current control is performed so that the sum of the cleaning current i2 applied to the cleaning roller 32 and the transfer current i1 applied to the transfer roller 30 becomes a predetermined transfer current i (i = i1 + i2). Is called.

  As described above, the current value to be applied to the cleaning roller 32 and the transfer roller 30 is controlled at a constant current, and the moving mechanism of the cleaning roller 32 is provided for the above embodiment, so that the image transfer is not affected. The transfer roller 30 can be cleaned even during printing.

  In the above embodiment, the continuous paper image forming apparatus that prints a color image is applied. However, the present invention is not limited to this. For example, the image forming unit 12 is provided and monochrome printing is performed. The present invention may be applied to an image forming apparatus for continuous paper.

  In the above embodiment, the moving mechanism using the cam is applied as the moving mechanism of the transfer roller 30, the guide roller 36, and the cleaning roller 32 of the modification. However, the present invention is limited to the above embodiment. For example, a moving mechanism using an actuator, a motor, or the like as appropriate can be used.

  In the above-described embodiment, the transfer roller 30, the guide roller 36, and the cleaning roller 32 of the modified example are provided with moving mechanisms to move each roller, but the transfer unit 24 itself is moved with respect to the photosensitive drum 14. The guide roller 36 is fixed in the transfer unit 24 by providing a mechanism that moves to a position where the transfer roller 30 is separated and a position where the transfer is performed, and the transfer roller 30 is in contact with the cleaning roller 32 and a position where the guide roller 36 is separated. A mechanism for moving within the transfer unit 24 is provided, and the transfer roller 30 is moved to the third position and the guide roller 36 is moved to the second position by a combination of the movement of the transfer unit 24 and the movement of the transfer roller 30. Good.

1 is a diagram illustrating an overall configuration of an image forming apparatus for continuous paper according to an embodiment of the present invention. It is a figure which shows the state of a transfer roller, a cleaning roller, and a guide roller. It is a figure which shows the position at the time of printing of a transfer roller and a guide roller. It is a figure which shows the position at the time of the cleaning of a transfer roller and a guide roller. It is a figure which shows the position at the time of the standby of a transfer roller and a guide roller. FIG. 3 is a block diagram illustrating a configuration of a control system for operating a cleaning mechanism of the continuous sheet image forming apparatus according to the embodiment of the present invention. 6 is a flowchart showing an example of the operation flow of the continuous sheet image forming apparatus according to the embodiment of the present invention. It is a figure which shows the position at the time of printing of a transfer roller, a cleaning roller, and a guide roller. It is a figure which shows the position at the time of the standby of a transfer roller, a cleaning roller, and a guide roller. It is a figure for demonstrating the current control of the cleaning roller and the transfer roller in the modification of the image forming apparatus for continuous paper concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus for continuous paper 30 Transfer roller 32 Cleaning roller 34 Cleaning blade 36 Guide roller 38 Transfer roller holding member 42, 48, 74 Spring 44, 50, 76 Cam 46 Guide roller holding member 60 Control circuit 64 Transfer roller moving cam rotation Motor 66 Guide roller moving cam rotation motor 68 Transfer drive circuit 70 Cleaning drive circuit 72 Cleaning roller holding member P Continuous paper

Claims (8)

An electrophotographic apparatus, comprising: a transfer roller that transfers an image to continuous paper; a guide roller that guides the continuous paper to the transfer roller when the image is transferred by the transfer roller; and a cleaning roller that cleans the transfer roller. An image forming apparatus for continuous paper that forms an image on continuous paper using a method,
The guide roller has three positions: a transfer position for transferring an image by the transfer roller, a cleaning position for cleaning by the cleaning roller, and a retracted position for non-transfer and non-cleaning, and the guide roller Has a guide position for guiding continuous paper and a guide retracting position for non-guide the continuous paper. An image forming apparatus for continuous paper that forms an image on continuous paper using an electrophotographic method,
A cleaning mechanism having a cleaning roller for cleaning a transfer roller for transferring an image to continuous paper;
A transfer mechanism that includes the transfer roller and moves the transfer roller to three positions: a transfer position for transferring an image, a cleaning position for cleaning the transfer roller, and a retracted position for non-transfer and non-cleaning; ,
It has a guide roller for guiding the continuous paper conveyed through the transfer mechanism, and the guide roller is moved to two positions: a guide position for guiding the continuous paper and a guide retracting position for making the continuous paper non-guide. A guide mechanism;
An image forming apparatus for continuous paper, comprising:   The continuous sheet image forming apparatus according to claim 2, further comprising a control unit configured to control the cleaning mechanism, the transfer mechanism, and the guide mechanism.   The control unit controls the cleaning mechanism, the transfer mechanism, and the guide mechanism so that the transfer roller is cleaned by the cleaning roller during non-printing regardless of the presence or absence of continuous paper. Item 4. The continuous paper image forming apparatus according to Item 3.   The control unit controls the cleaning mechanism, the transfer mechanism, and the guide mechanism so as to perform cleaning by setting a cleaning time in accordance with a printing amount on continuous paper. The continuous paper image forming apparatus according to claim 4.   4. The continuous paper according to claim 3, wherein the control unit controls the cleaning mechanism, the transfer mechanism, and the guide mechanism so that the transfer roller and the cleaning roller are always in contact with each other during printing. Image forming apparatus.   The control means further controls a current value applied to the transfer roller and the cleaning roller so that a sum of current values flowing through the transfer roller and the cleaning roller becomes a transfer current value. 6. An image forming apparatus for continuous paper as described in 6.   The image forming apparatus for continuous paper according to any one of claims 1 to 7, wherein the cleaning roller is made of a photosensitive material that is charged to a polarity opposite to that of the toner.

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