JP6558236B2 - Sheet correction apparatus and image forming system - Google Patents

Description

  The present invention relates to a sheet correction apparatus and an image forming system.

  2. Description of the Related Art Conventionally, a paper correction device that corrects paper curl is known. In this paper correction device, for example, the paper curl is corrected by using a paper conveyance path curved in the direction opposite to the curl direction (the direction in which the curled paper protrudes). Specifically, a sheet correction mechanism is formed by a conveying belt that contacts one surface of the sheet and a circular shaft member that contacts the other surface of the sheet and extends in the width direction of the conveying belt, and the circular shaft member is difficult to convey. The curved path for correcting the sheet is formed by moving the sheet so as to be embedded (see, for example, Patent Documents 1 and 2).

  In addition, the above-described sheet correction apparatus cools the sheet when correcting the sheet. That is, the sheet correction device cools the circular shaft member in advance by blowing cooling air to the circular shaft member of the sheet correction mechanism, for example. Thus, the sheet is cooled by the circular shaft member when passing through the curved path.

JP 2003-137467 A JP 2007-22756 A

  Here, in the paper correction apparatuses described in Patent Documents 1 and 2, as the curl amount of the paper (the protruding amount of the curled paper) increases, the circular shaft member is inserted into the transport belt more and forms a curved path. . In the greatly curved path, the contact area of the circular shaft member with the conveyance belt is large, and the sheet is in long contact with the circular shaft member when conveyed on the curved path, so that the cooling effect is enhanced. On the other hand, in the small curved path, the contact area of the circular shaft member with respect to the conveyance belt is small, and the sheet is not so in contact with the circular shaft member when being conveyed through the curved path, so that the cooling effect is low. As described above, in the sheet correction device, the cooling capacity changes according to the contact area where the circular shaft member contacts the conveyance belt.

  Therefore, when the sheet correction mechanism is provided so that the bending direction is different between the upstream side and the downstream side of the sheet conveyance path as in Patent Document 1, the degree of bending is different between the upstream side and the downstream side. Therefore, the cooling capacity of the front and back of the paper is different. That is, a temperature difference occurs between the front and back of the paper. Such a temperature difference between the front and back of the paper results in a color error due to a thermochromism phenomenon after the paper is curled.

  The present invention has been made to solve such a problem, and the object of the present invention is to provide a sheet correction device that can suppress a temperature difference between the front and back of a sheet and suppress a color error due to a thermochromism phenomenon. And providing an image forming system.

  In order to achieve the above object, a sheet correction apparatus according to the present invention includes a curl sensor for detecting a curl direction and a curl amount of a sheet to be conveyed, and a sheet of a sheet to be conveyed that is provided on the downstream side of the curl sensor. It can be pressed against the transport belt by contacting the transport belt that contacts one side and the other side of the transported paper and moving in a direction that intersects the paper transport direction by the transport belt. A circular shaft member extending in the width direction, and a first sheet correction unit capable of adjusting a contact area of the circular shaft member with the conveyance belt, and cooling air for the circular shaft member of the first sheet correction unit A first air blowing means for blowing air, a conveyance belt provided on the downstream side of conveyance from the first sheet correction unit and contacting the other side of the conveyed sheet, and a surface of the conveyed sheet when contacting one side. A circular shaft member that can be pressed against the conveyance belt by moving in a direction crossing the paper conveyance direction by the conveyance belt and extends in the width direction of the conveyance belt, and the circular shaft member with respect to the conveyance belt A second sheet correction unit capable of adjusting the contact area of the sheet, a second blowing unit for blowing cooling air to the circular shaft member of the second sheet correction unit, and a curl direction and a curl amount detected through the curl sensor. And adjusting the contact area of the circular shaft member with respect to the conveyance belt of the first paper correction unit and the contact area of the circular shaft member with respect to the conveyance belt of the second paper correction unit, and adjusting the first paper correction Depending on the contact area of the circular shaft member with respect to the conveyor belt of the second portion and the contact area of the circular shaft member with respect to the conveyor belt of the second sheet correcting portion. Characterized in that it comprises control means for controlling at least one of blowing amount of air means.

  According to the paper straightening device of the present invention, in order to control the blown amount of at least one of the first and second blower means in accordance with the contact area of the circular shaft member with the conveyance belt of the first and second paper straightening units. Even if the contact area of the circular shaft member with respect to the conveyor belt is different, the difference in cooling capacity between the front and back surfaces can be suppressed by adjusting the air flow rate. This suppresses the temperature difference between the front and back of the paper. Therefore, the temperature difference between the front and back sides of the sheet can be suppressed, and the color error due to the thermochromism phenomenon can be suppressed.

  Further, in the paper correction device according to the present invention, the curl direction and the curl amount of the paper, the contact area of the circular shaft member with respect to the conveyance belt of the first and second paper correction parts, and the first and second air blowing means The apparatus further comprises storage means for storing a data table in which the air flow rate is associated, and the control means is based on a curl direction and a curl amount detected through the curl sensor and a data table stored by the storage means. It is preferable to control the contact area of the circular shaft member with respect to the conveyor belt of the first and second paper correction sections and the air flow rate of at least one of the first and second air blowing means.

  According to this paper correction device, a data table in which the curl direction and the curl amount of the paper, the contact area of the circular shaft member, and the air blowing amount are associated with each other is stored, and control is performed based on the data table. By simply applying the curl direction and curl amount to the data table, it is possible to determine the control contents and reduce the processing load.

  Further, in the paper correction device according to the present invention, the first and second air blowing means are installed so as to blow air to the respective circular shaft members from the opposite side of the paper contact side of the respective circular shaft members. Preferably it is.

  According to this paper straightening device, the first and second air blowing means are installed so as to blow air to each circular shaft member from the side opposite to the paper contact side of each circular shaft member. And the cooling air from a 2nd ventilation means will be sent toward a circular shaft member, without being interrupted by a conveyance belt. Therefore, it can contribute to the improvement of the cooling capacity.

  Further, in the sheet correction device according to the present invention, the control unit increases the amount of air blown by the first blowing unit as the contact area of the circular shaft member with respect to the conveyance belt of the first sheet correction unit decreases. The smaller the contact area of the circular shaft member with the transport belt of the second paper correction unit, the larger the amount of air blown by the second air blowing means.

  According to this paper straightening device, the smaller the contact area of the circular shaft member with respect to the transport belt of the first and second paper straightening sections, the larger the blowing amount of the first and second blower means, so the contact area becomes smaller. However, the air flow rate can be increased to prevent the cooling capacity from being lowered. Also, by controlling the air flow rate of both the air blowing means, compared to the case where the air flow rate of one air blowing means is controlled, the load can be suppressed for that one air blowing means, and the possibility of failure is reduced. be able to.

  In the paper correction device according to the present invention, when the control unit determines that there is no need for paper correction based on the curl direction and the curl amount detected through the curl sensor, the first and second papers. It is preferable to control the contact area of the circular shaft member with respect to the conveying belt of the correction unit to the maximum value and to control the blowing amount of the first and second blowing means to the maximum.

  According to this paper correction device, when it is determined that there is no need for paper correction, the contact area of the circular shaft member with respect to the transport belt of the first and second paper correction portions is controlled to the maximum value, and the first and second The air volume of the air blowing means is controlled to the maximum. For this reason, when there is no need to correct the sheet, the sheet can be efficiently cooled by performing control specialized for cooling with emphasis on cooling of the sheet.

  According to another aspect of the present invention, there is provided an image forming system comprising: the sheet correcting apparatus according to any one of the above; and an image forming apparatus that forms an image on the sheet and supplies the sheet to the sheet correcting apparatus. Features.

  According to the image forming system of the present invention, it is possible to provide an image forming system that can suppress a temperature difference between the front and back sides of a sheet and suppress a color error due to a thermochromism phenomenon.

  According to the present invention, it is possible to provide a sheet correction apparatus and an image forming system capable of suppressing a temperature difference between the front and back of a sheet and suppressing a color error due to a thermochromism phenomenon.

1 is a schematic configuration diagram illustrating an image forming system including a sheet correction apparatus according to an embodiment. It is a block diagram which shows the detail of the paper correction | amendment mechanism part shown in FIG. FIG. 2 is a configuration diagram illustrating details of an image reading mechanism unit illustrated in FIG. 1. It is a conceptual diagram which shows the mechanism which a temperature difference generate | occur | produces in the front and back of a paper. It is a conceptual diagram which shows the mode of the ventilation volume control of the control part shown in FIG. It is a conceptual diagram which shows an example of the data table memorize | stored by the control part shown in FIG. It is a flowchart which shows the control method of the paper correction apparatus which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

  FIG. 1 is a schematic configuration diagram illustrating an image forming system including a sheet correction device according to the present embodiment. An image forming system 1 illustrated in FIG. 1 includes an image forming apparatus A and a post-processing apparatus B that performs post-processing on a sheet S on which an image is formed by the image forming apparatus A.

  The image forming apparatus A is a tandem color type that forms a full-color image on the paper S by arranging a plurality of photoconductors facing a single intermediate transfer belt in the vertical direction, 1 includes an image reading device 2 including an automatic document feeder and a scanning exposure device, and includes an image forming unit 3 and a plurality of paper feed trays 4 at a lower portion.

  The image reading device 2 transports a document placed on a document tray of an automatic document transport device by a transport unit, scans and exposes an image on one or both sides of the document, and reads image information. The image reading device 2 is also configured to read image information of a document placed on the contact glass.

  The image forming unit 3 receives the supply of paper S from a plurality of paper feed trays 4 and is based on image information read by the image reading device 2 or image information transmitted from a PC (personal computer) or the like. Thus, an image is formed on the paper S.

  The image forming unit 3 includes an image transfer unit 3a and a fixing unit 3b. The image transfer unit 3a forms a toner image on the photosensitive member by an electrophotographic process that performs charging, exposure, and development, and transfers the image to the paper S. In the present embodiment, the image transfer unit 3a is of a type having an intermediate transfer belt, toner images on a plurality of photoconductors are transferred to the intermediate transfer belt, and toner images on the intermediate transfer belt are transferred to the paper S. The

  The fixing unit 3b forms a nip portion that transports the paper S with a heating roller and a pressure roller, melts the toner by heating and pressurizing while transporting the paper S, and transfers the toner onto the paper S by the image transfer unit 3a. The printed image is fixed on the paper S.

  Further, the image forming apparatus A includes a reversing path 5 that leads from the downstream side of the fixing unit 3b to the upstream side of the image transfer unit 3a. The reverse path 5 is a path for re-transporting the paper S to the image transfer unit 3a after reversing the front and back of the paper S. By this reversal path 5, front and back images can be formed on the paper S.

  The post-processing apparatus B performs cutting (including punching), humidifying, folding, stapling, curl correction, and the like on the paper S. The post-processing apparatus B includes various paths R1 to R3, a paper discharge tray Tr, a paper correction mechanism C, an image reading mechanism D, and a control unit (control unit, storage unit) 90. The first path R1 is a path for receiving the image-formed sheet S and transporting it to the sheet correction mechanism C, and the second path R2 is for the sheet S that has passed through the sheet correction mechanism C to the image reading mechanism D. It is a route to carry. The third path R3 is a path for transporting the paper S that has passed through the image reading mechanism D to the paper discharge tray Tr. The sheet correction mechanism C and the control unit 90 constitute a sheet correction apparatus according to this embodiment.

  In the present embodiment, the third path R3 guides the paper S to the paper discharge tray Tr, but a folding mechanism, a stapling mechanism, or the like may be provided on the third path R3. In addition, other mechanisms such as a cutting mechanism and a humidifying mechanism may be provided in the first and second paths R1 and R2.

  FIG. 2 is a configuration diagram showing details of the sheet correction mechanism C shown in FIG. The paper correction mechanism C shown in FIG. 2 includes a curl sensor 10, a first paper correction unit 20, a first fan (first air blower) 30, a second paper correction unit 40, and a second fan (second fan). Air blowing means) 50. Such a sheet correction mechanism C is provided in the order of the curl sensor 10, the first sheet correction unit 20 and the first fan 30, and the second sheet correction unit 40 and the second fan 50 from the upstream side in the sheet conveyance direction. ing.

  The curl sensor 10 is, for example, an optical sensor provided on the upstream side of the first paper correction unit 20 and has a function of irradiating light to the conveyed paper S and a function of receiving reflected light. . Irradiation of light from the curl sensor 10 is performed based on a control signal from the control unit 90. Further, when receiving the reflected light, the curl sensor 10 transmits information to that effect to the curl sensor 10. Accordingly, the control unit 90 detects the curl direction and the curl amount of the paper S based on the time from when the light is irradiated until the reflected light returns.

  The first sheet correction unit 20 performs decurling to correct the curl of the sheet S, and includes a decurling belt (conveying belt) 21, a plurality (three) of rollers 22 to 24, and a hollow pipe (circular shaft member). 25.

  The decurling belt 21 is an endless belt that contacts the one surface side of the conveyed paper S and conveys the paper S. The decal belt 21 is wound around a plurality of rollers 22-24. Any one of the plurality of rollers 22 to 24 is a driving roller, which rotates the decal belt 21, and the other is a driven roller.

  The hollow pipe 25 is a metal pipe (for example, shaft diameter φ6) that extends in the width direction of the decurling belt 21 in contact with the other side of the sheet S to be conveyed. The hollow pipe 25 may be supported to be rotatable or may be supported to be non-rotatable. Further, the hollow pipe 25 is configured to be movable in a direction intersecting with the sheet conveying direction by the decurling belt 21 (more specifically, a direction perpendicular to the belt surface of the decurling belt 21 that is not curved). The hollow pipe 25 can be pressed against the decal belt 21 by this movement (see broken line). That is, the first sheet correction unit 20 can adjust the degree of curvature of the conveyance path and the contact area of the hollow pipe 25 with the decurling belt 21 by controlling the amount of movement of the hollow pipe 25 to the decurling belt 21. ing.

  The first fan 30 blows cooling air to the hollow pipe 25 of the first sheet correction unit 20. The first fan 30 is located on the opposite side to the contact side of the paper S in the hollow pipe 25, and blows air to the hollow pipe 25 from this position. Thereby, the hollow pipe 25 is efficiently cooled without the cooling air being blocked by the decal belt 21.

  The second paper correction unit 40 performs decurling to correct the curl of the paper S, and performs decurling in the opposite direction to the first paper correction unit 20. Such a second sheet correction unit 40 includes a decurling belt (conveying belt) 41, a plurality (three) of rollers 42 to 44, and a hollow pipe (circular shaft member) 45. These are the same as those of the first sheet correction unit 20, but a part of the arrangement relationship is different from that of the first sheet correction unit 20 because the curve direction of the path is opposite.

  First, the decurling belt 41 is in contact with the other surface side of the conveyed paper S and is wound around a plurality of rollers 42 to 44. Any one of the plurality of rollers 42 to 44 is a driving roller, and the other is a driven roller.

  The hollow pipe 45 has the same size and the same shape as the first paper correction unit 20, and is a metal pipe that contacts the one surface side of the conveyed paper S and extends in the width direction of the decal belt 41. The hollow pipe 45 can be pressed against the decal belt 41 by moving in the vertical direction described above. Therefore, the second sheet correction unit 40 can adjust the degree of curvature of the conveyance path and the contact area of the hollow pipe 45 with respect to the decurling belt 41 by controlling the amount of movement of the hollow pipe 45 to the decurling belt 41. ing.

  The second fan 50 is the same as the first fan 30 and blows cooling air to the hollow pipe 45 of the second paper correction unit 40. The second fan 50 is located on the opposite side of the hollow pipe 45 from the contact side of the paper S, and blows air to the hollow pipe 45 from this position.

  Reference is again made to FIG. The image reading mechanism D reads an image formed on the paper S and calibrates it. FIG. 3 is a configuration diagram showing details of the image reading mechanism D shown in FIG. As shown in FIG. 3, the image reading mechanism unit D includes a first image reading unit 60, a second image reading unit 70, and a spectrocolorimeter 80.

  The first and second image reading units 60 and 70 are scanner devices such as a color CCD (Charge-Coupled Device) line sensor that scans an image formed on the paper S. Among these, the first image reading unit 60 is provided on the upstream side of the second image reading unit 70, and reads image information formed on the other side of the paper S. On the other hand, the second image reading unit 70 is provided on the downstream side of the first image reading unit 60 and reads image information formed on one surface of the paper S. The spectrocolorimeter 80 is a kind of photometer, and determines the color of an image formed on the paper S by measuring the intensity for each color (more precisely, for each wavelength of light). It is. The spectrocolorimeter 80 measures the intensity of each color of the image formed on one side of the paper S.

  Here, in the prior art, for example, since the air flow of the first and second fans 30 and 50 is constant, a temperature difference may occur between the front and back of the sheet S that has passed through the sheet correction mechanism C, and this temperature difference. May be affected by the phenomenon of thermochromism.

  FIG. 4 is a conceptual diagram showing a mechanism for generating a temperature difference between the front and back sides of the paper S. As shown in FIG. 4, for example, it is assumed that the sheet S is curved so as to be convex toward the other side. In this case, the first sheet correction unit 20 performs decurling by forming a strong curved path. On the other hand, the second sheet correction unit 40 performs decurling by forming a weak curved path.

  For this reason, the first sheet correction unit 20 and the second sheet correction unit 40 have different contact areas of the hollow pipes 25 and 45 with respect to the decurling belts 21 and 41, and the sheet S with respect to the hollow pipes 25 and 45 during conveyance of the sheet S. The contact area (contact time) will also be different. Therefore, the first sheet correction unit 20 and the second sheet correction unit 40 have different cooling capacities. In particular, the first sheet correction unit 20 preferentially cools the other side because the hollow pipe 25 is positioned on the other side of the sheet S, and the second sheet correction unit 40 has the hollow pipe 45 on one side of the sheet S. Since one side is located, one side is cooled preferentially. Therefore, the other side of the sheet S is greatly cooled in the first sheet correction unit 20, but the one side of the sheet S is not significantly cooled in the second sheet correction unit 40, and a temperature difference occurs between the front and back sides of the sheet S. .

  Specifically, the temperature will be described. First, it is assumed that the temperature of one side and the other side of the sheet S is 80 ° C. In this case, after the sheet S passes through the first sheet correction unit 20, for example, the temperature on one side becomes 70 ° C. and the temperature on the other side becomes 60 ° C. That is, the other surface is greatly cooled. However, after the sheet S passes through the second sheet correcting unit 40, for example, the temperature on one side becomes 66 ° C and the temperature on the other side becomes 58 ° C. That is, the second sheet correction unit 40 does not cool the surface of the sheet S as much as the first sheet correction unit 20. Therefore, a temperature difference of, for example, 8 ° C. occurs between one side of the sheet S and the other side.

  When such a temperature difference occurs, even if images are formed with the same color on the front and back sides of the paper S, the first and second image reading units 60 and 70 are scanned as slightly different colors. Even when calibration is performed based on the color measurement result of the spectrocolorimeter 80, the scanned image information is calibrated based on the color measurement result on one side, so that one side is appropriately calibrated. However, it is hard to say that the other side is properly calibrated.

  In the present embodiment, the control unit 90 has two major functions. In particular, the control unit 90 according to the present embodiment controls the air volume of the first fan 30 and the second fan 50 as a second function, and suppresses the temperature difference between the front and back of the paper S. Details will be described below.

  First, as a first function, the control unit 90 has a contact area of the hollow pipe 25 with respect to the decurling belt 21 of the first sheet correction unit 20 according to the curl direction and the curl amount detected through the curl sensor 10, and The contact area of the hollow pipe 45 with respect to the decurling belt 41 of the second paper correction unit 40 is adjusted. This function is the same as that described with reference to FIG.

  Furthermore, as a second function, the control unit 90 controls the air flow rate of the first fan 30 according to the contact area of the hollow pipe 25 of the first paper correction unit 20 and the second paper correction unit 40. The air flow rate of the second fan 50 is controlled according to the contact area of the hollow pipe 45.

  FIG. 5 is a conceptual diagram showing a state of air flow control by the control unit 90 shown in FIG. The controller 90 increases the air flow rate of the first fan 30 as the contact area of the hollow pipe 25 of the first paper correction unit 20 decreases, and decreases the contact area of the hollow pipe 45 of the second paper correction unit 40. The air flow rate of the second fan 50 is increased.

  More specifically, for example, it is assumed that the sheet S is curved so as to be convex toward the other side. In this case, the first sheet correction unit 20 performs decurling by forming a strong curved path. On the other hand, the second sheet correction unit 40 performs decurling by forming a weak curved path. At this time, the control unit 90 decreases the air volume of the first fan 30 and increases the air volume of the second fan 50. Thereby, the occurrence of a temperature difference due to a difference in contact area is suppressed.

  For example, the front and back temperatures of the paper S are as follows, for example. First, it is assumed that the temperature of one side and the other side of the paper S is 80 ° C. In this case, after the sheet S passes through the first sheet correction unit 20, the contact area of the hollow pipe 25 with the decurling belt 21 is large, so that, for example, the temperature on one side becomes 70 ° C and the temperature on the other side becomes 65 ° C. It becomes. Then, after the sheet S passes through the second sheet correction unit 40, since the amount of air blown by the second fan 50 is large, for example, the temperature on one side becomes 60 ° C and the temperature on the other side becomes 60 ° C. In this way, the amount of air blown from the first and second fans 30 and 50 is adjusted according to the difference in the contact area between the hollow pipes 25 and 45, and the temperature difference between one side of the sheet S and the other side is suppressed.

  Note that the control unit 90 controls the air flow rate of the first and second fans 30 and 50 as a second function, but is not limited thereto, and the air flow rate of the first fan 30 is fixed and the second fan is fixed. One air flow rate may be controlled, such as controlling the air flow rate of 50. This is also because the temperature difference between the front and back of the paper S can be suppressed.

  Here, the control unit 90 according to the present embodiment preferably stores a data table for performing the above control. FIG. 6 is a conceptual diagram showing an example of a data table stored by the control unit 90 shown in FIG. As shown in FIG. 6, the control unit 90 includes a curl direction and a curl amount of the paper S, a contact area of the hollow pipes 25 and 45 with respect to the decurling belts 21 and 41 of the first and second paper correction units 20 and 40, The data table which matched the ventilation volume of the 1st and 2nd fans 30 and 50 is memorized.

  Specifically, when the curl of the sheet S is greatly convex toward the other side in the data table (in the first state), the control unit 90 moves toward the decurling belt 21 side of the hollow pipe 25 of the first sheet correcting unit 20. Is stored as “large” (ie, the contact area is stored as “large”), and the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 is stored as “small”. (Ie, the contact area is stored as “small”). In addition, the air volume of the first fan 30 is stored as “small”, and the air volume of the second fan 50 is stored as “large”.

  Further, when the curl of the sheet S is convex to some extent on the other side in the data table (when it is in the second state), the control unit 90 of the hollow pipe 25 of the first sheet correction unit 20 The amount of movement toward the decal belt 21 is stored as “medium” (that is, the contact area is stored as “medium”), and the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 is stored as “small”. (Ie, the contact area is stored as “small”). Further, the air volume of the first fan 30 is stored as “medium”, and the air volume of the second fan 50 is stored as “large”.

  In addition, when the sheet S is not curled or small (in the third state) in the data table, the control unit 90 sets the amount of movement of the hollow pipe 25 of the first sheet correcting unit 20 toward the decurling belt 21 to “medium”. ”(That is, the contact area is stored as“ medium ”), and the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 is stored as“ medium ”(that is, the contact area is stored as the contact area). I remember “medium”). In addition, the air volume of the first fan 30 is stored as “small”, and the air volume of the second fan 50 is stored as “small”.

  Further, when the curl of the sheet S is convex to a certain extent on the one side in the data table (in the fourth state), the control unit 90 decals the hollow pipe 25 of the first sheet correction unit 20. The amount of movement toward the belt 21 is stored as “small” (that is, the contact area is stored as “small”), and the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 is stored as “medium”. (That is, the contact area is memorized as “medium”). In addition, the air flow rate of the first fan 30 is stored as “large”, and the air flow rate of the second fan 50 is stored as “medium”.

  In addition, when the curl of the sheet S is greatly convex on one side in the data table (in the fifth state), the control unit 90 moves the hollow pipe 25 of the first sheet correction unit 20 to the decurling belt 21 side. The amount of movement is stored as “small” (that is, the contact area is stored as “small”), and the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 is stored as “large”. (In other words, the contact area is memorized as “large”). In addition, the air flow rate of the first fan 30 is stored as “large”, and the air flow rate of the second fan 50 is stored as “small”.

  Since such a data table is stored, the control unit 90 has the hollows of the first and second sheet correction units 20 and 40 based on the curl direction and the curl amount detected by the curl sensor 10 and the data table. The contact area of the pipes 25 and 45 and the air volume of the first and second fans 30 and 50 are controlled. That is, when the curl sensor 10 detects the curl direction and the curl amount, the control unit 90 compares the curl amount with a plurality of predetermined threshold values, and enters any one of the first to fifth states of the data table. Determine if it applies. The control unit 90 controls the first and second sheet correction units 20 and 40 and the first and second fans 30 and 50 based on the determination result and the contents of the data table.

  Here, the control unit 90 determines that there is no need for paper correction based on the curl direction and the curl amount detected by the curl sensor 10 (when the data table is in the third state), It is preferable to control the contact area of the hollow pipes 25 and 45 of the second paper correction units 20 and 40 to the maximum value and to control the air flow rate of the first and second fans 30 and 50 to the maximum. This is because control with an emphasis on cooling of the paper S can be performed when there is no need for paper correction.

  In this case, in the data table, the amount of movement of the hollow pipe 25 of the first sheet correction unit 20 toward the decal belt 21 side, the amount of movement of the hollow pipe 45 of the second sheet correction unit 40 toward the decal belt 41 side, What is necessary is just to memorize | store "large" in all the ventilation volume of the 1st fan 30, and the ventilation volume of the 2nd fan 50.

  Next, a method for controlling the sheet correction apparatus according to the present embodiment will be described. FIG. 7 is a flowchart showing a control method of the sheet correction apparatus according to the present embodiment. As shown in FIG. 7, first, the control unit 90 determines the curl direction and the curl amount based on the signal from the curl sensor 10, and determines which of the first to fifth states corresponds to the data table ( S1).

  Next, the control unit 90 controls the amount of movement of the hollow pipe 25 in the first sheet correction unit 20 and the amount of air blown from the first fan 30 based on the state determined in step S1 and the data table. (S2). Next, the control unit 90 controls the amount of movement of the hollow pipe 45 in the second sheet correction unit 40 and the amount of air blown from the second fan 50 based on the state determined in step S1 and the data table. (S3).

  Thereafter, the process shown in FIG. 7 ends. Note that the processing shown in FIG. 7 is repeatedly executed, for example, every time the paper S is transported or every time a predetermined number of sheets are transported.

  Thus, according to the sheet correction apparatus and the image forming system 1 according to the present embodiment, according to the contact area of the hollow pipes 25 and 45 with the decal belts 21 and 41 of the first and second sheet correction units 20 and 40. Even if the contact areas of the hollow pipes 25 and 45 with respect to the decal belts 21 and 41 are different in order to control the amount of air flow of at least one of the first and second fans 30 and 50, Adjustment can suppress the difference in cooling capacity between the front and back sides. Thereby, the temperature difference between the front and back of the paper S is suppressed. Therefore, the temperature difference between the front and back sides of the sheet can be suppressed, and the color error due to the thermochromism phenomenon can be suppressed.

  Further, a data table in which the curl direction and the curl amount of the paper S, the contact area of the hollow pipes 25 and 45, and the air blowing amount are stored and controlled based on the data table is detected by the curl sensor 10. By simply applying the curl direction and the curl amount of the paper S to the data table, the control content can be determined and the processing load can be reduced.

  Further, since the first and second fans 30 and 50 are installed so as to blow air to the respective hollow pipes 25 and 45 from the side opposite to the paper contact side of the respective hollow pipes 25 and 45, the first and second fans 30 and 50 The cooling air from the second fans 30 and 50 is sent to the hollow pipes 25 and 45 without being blocked by the decal belts 21 and 41. Therefore, it can contribute to the improvement of the cooling capacity.

  Further, the smaller the contact area of the hollow pipes 25 and 45 with the decurling belts 21 and 41 of the first and second paper correction sections 20 and 40, the larger the blowing amount of the first and second fans 30 and 50. Even if the area is reduced, the air flow rate can be increased to prevent the cooling capacity from being lowered. Further, by controlling the air flow rate of both fans 30 and 50, compared to the case of controlling the air flow rate of one fan, the load can be suppressed for that one fan, and the possibility of failure is reduced. be able to.

  Further, when it is determined that the sheet correction is not necessary, the contact areas of the hollow pipes 25 and 45 with respect to the decal belts 21 and 41 of the first and second sheet correction portions 20 and 40 are controlled to the maximum value, and the first and The air flow rate of the second fans 30 and 50 is controlled to the maximum. For this reason, when there is no need for sheet correction, the sheet S can be efficiently cooled by performing control specialized for cooling with emphasis on the cooling of the sheet S.

  As described above, the sheet correction apparatus and the image forming system according to the present invention have been described based on the embodiments. However, the present invention is not limited thereto, and modifications may be made without departing from the spirit of the present invention. Alternatively, if possible, a known technique or the like may be combined with the technique described in the embodiment.

  For example, in this embodiment, the hollow pipes 25 and 45 are used, but a solid cylindrical member may be used. The hollow pipes 25 and 45 are configured to be movable in the vertical direction described above. However, the hollow pipes 25 and 45 are not limited to the vertical direction. If the hollow pipes 25 and 45 can be brought into contact with the decal belts 21 and 41, the hollow pipes 25 and 45 move slightly in the diagonal direction. It may be possible.

  Further, in the above embodiment, the sheet correction mechanism C is incorporated in the post-processing device B connected to the subsequent stage of the image forming apparatus A. However, the present invention is not limited thereto, and is not connected to the image forming apparatus A and after image formation. This may be applied to an off-line finisher that performs post-processing on the paper S alone. In this case, the offline finisher may be provided with means for acquiring the curl direction and the curl amount of the paper S.

1: Image forming system 2: Image reading device 3: Image forming unit 3a: Image transfer unit 3b: Fixing unit 4: Paper feed tray 5: Reverse path 10: Curl sensor 20: First paper correction unit 21: Decal belt (conveyance) belt)
25: Hollow pipe (circular shaft member)
30: 1st fan (1st ventilation means)
40: 2nd paper correction part 41: Decal belt (conveyance belt)
45: Hollow pipe (circular shaft member)
50: 2nd fan (2nd ventilation means)
60: 1st image reading part 70: 2nd image reading part 80: Spectral colorimeter 90: Control part (control means, storage means)
A: Image forming apparatus B: Post-processing apparatus C: Paper correction mechanism part D: Image reading mechanism part S: Paper Tr: Paper discharge tray

Claims (6)

A curl sensor for detecting the curl direction and the curl amount of the conveyed paper;
A conveyance belt provided on the downstream side of the curl sensor and in contact with one side of the conveyed paper, and in contact with the other side of the conveyed paper and moving in a direction intersecting the paper conveyance direction by the conveyance belt. A circular shaft member that can be pressed against the transport belt and extends in the width direction of the transport belt, and a first sheet correction unit that can adjust a contact area of the circular shaft member with the transport belt,
First air blowing means for blowing cooling air to the circular shaft member of the first paper correction section;
A conveyance belt that is provided on the downstream side of conveyance from the first sheet correction unit and that contacts the other side of the sheet to be conveyed, and that contacts one side of the sheet to be conveyed and intersects the sheet conveyance direction by the conveyance belt. And a circular shaft member that can be pressed against the transport belt by moving in the direction of movement and that extends in the width direction of the transport belt, and is capable of adjusting a contact area of the circular shaft member with respect to the transport belt. A paper correction section;
Second air blowing means for blowing cooling air to the circular shaft member of the second paper correction section;
The contact area of the circular shaft member with the conveyance belt of the first paper correction unit and the contact of the circular shaft member with the conveyance belt of the second paper correction unit according to the curl direction and the curl amount detected through the curl sensor. The first blower is adjusted in accordance with the contact area of the circular shaft member with the conveyance belt of the first paper correction unit and the contact area of the circular shaft member with the conveyance belt of the second paper correction unit. Control means for controlling the air blowing amount of at least one of the means and the second air blowing means;
A sheet correction apparatus comprising: A data table is stored in which the curl direction and the curl amount of the paper, the contact area of the circular shaft member with respect to the conveyance belt of the first and second paper correction units, and the air flow rate of the first and second air blowing means are associated with each other. And further storing means for
The control unit is configured to control a circular shaft member with respect to the conveyance belt of the first and second paper correction units based on a curl direction and a curl amount detected through the curl sensor and a data table stored by the storage unit. The sheet correction apparatus according to claim 1, wherein a contact area and a blowing amount of at least one of the first and second blowing units are controlled. The said 1st and 2nd ventilation means is installed so that it may blow with respect to each said circular shaft member from the paper contact side of each circular shaft member from the opposite side. Item 3. The sheet correction apparatus according to any one of Items 2 to 3. The control means increases the amount of air blown by the first blower means as the contact area of the circular shaft member with the transport belt of the first paper correction section decreases, and the circular shaft of the second paper correction section with respect to the transport belt. The paper straightening device according to any one of claims 1 to 3, wherein an amount of air blown by the second air blowing unit is increased as a contact area of the member is reduced. When the control means determines that there is no need for paper correction based on the curl direction and the curl amount detected through the curl sensor, the circular shaft member contacts the conveyance belts of the first and second paper correction units. The sheet correction apparatus according to claim 4, wherein the area is controlled to a maximum value, and the air blowing amount of the first and second air blowing units is controlled to the maximum. The sheet correction device according to any one of claims 1 to 5,
An image forming apparatus that forms an image on a sheet and supplies the sheet to the sheet correction apparatus;
An image forming system comprising:

Images