JP6638611B2 - Decal device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a decurling apparatus for removing a curl of a sheet-like recording medium such as a sheet of paper, and an image forming apparatus having the same.

  2. Description of the Related Art Conventionally, in an electrophotographic or ink-jet recording type image forming apparatus such as a copying machine or a printer, a sheet may be curled. The main causes of such curling are shrinkage due to thermal fixing of a resin component contained in toner in an electrophotographic image forming apparatus, expansion of paper due to ink penetration in an ink jet type image forming apparatus, or temperature and humidity conditions. Examples include a paper humidity control function.

  Further, the degree of curling of the paper differs depending on conditions such as the thickness of the paper, basis weight (weight per unit area), print density (print ratio), and temperature and humidity. For example, in the ink jet recording method, the curl amount of thick paper is generally small and the curl amount of thin paper is large. Therefore, if the curl is corrected (decurled) at a constant rate, the amount of decurl becomes excessive for thick paper and the amount of decurl becomes insufficient for thin paper.

  Therefore, for example, Patent Document 1 discloses a decal including a hard roller having a hard peripheral surface, a soft roller pressed against the hard roller, and nip pressure switching means for switching a nip pressure between the hard roller and the soft roller. An apparatus is disclosed.

JP 2006-36489 A

  However, in the decurling device of Patent Literature 1 in which the sheet is passed through the nip portion of the pair of rollers to perform decurling, even if the nip pressure is adjusted, the decurling amount cannot be finely adjusted according to the conditions.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a decurling apparatus having a simple configuration capable of appropriately finely adjusting the decurling amount of a recording medium, and an image forming apparatus including the same.

  In order to achieve the above object, a first configuration of the present invention has a decurling belt, a decurling roller, a pressing mechanism, and a decurling amount adjusting mechanism, and a sheet-shaped nip portion between the decal belt and the decurling roller. This is a decurling device for correcting the curl of the recording medium by inserting the recording medium. The decal belt is endless, is wound around a driving roller and a driven roller, and comes into contact with the non-image forming surface of the recording medium. The decal roller contacts the outer peripheral surface of the decal belt to form a nip portion, and contacts the image forming surface of the recording medium. The pressing mechanism urges the driven roller in the direction of pressing the decal belt against the decal roller. The decurling amount adjusting mechanism adjusts the nip width of the nip by changing the position of the driven roller about the rotation axis of the decurling roller.

  According to the first configuration of the present invention, it is possible to set an appropriate decal amount according to the thickness, basis weight (basis weight), print density (print ratio), temperature and humidity of the recording medium with a simple configuration, Excess or deficiency of the decal amount can be effectively suppressed. Further, since the position of the driven roller is changed around the rotation axis of the decal roller, the positional relationship between the drive roller and the decal roller does not change. Therefore, the winding angle of the decal belt with respect to the decal roller can be changed while the contact state between the decal belt and the decal roller is always maintained.

FIG. 2 is a diagram illustrating an internal configuration of an inkjet recording type printer 100, which is an example of an image forming apparatus including the decurling device 14 of the present invention. External perspective view of a decurling device 14 according to an embodiment of the present invention. FIG. 2 is a perspective view showing the internal structure of the decurling device 14 of the present embodiment. Side sectional view of the decal device 14 of the present embodiment. FIG. 2 is a block diagram illustrating a driving mechanism of the decurling device 14 according to the present embodiment. FIG. 2 is an external perspective view of the decurling device 14 of the present embodiment and a transport guide portion 12 disposed upstream of the decurling device 14 in the sheet transport direction. FIG. 4 is a side view of the decurling device 14 of the present embodiment and the transport guide unit 12 disposed upstream of the decurling device 14 in the paper transport direction. FIG. 7 is a side view showing a change in the winding angle of the decal belt 23 with respect to the decur roller 25 as the driven roller 21 moves. Cross-sectional side view of the decurling device 14 of the present embodiment and the conveyance guide portion 12 disposed upstream of the decurling device 14 in the paper conveyance direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of an ink jet recording type printer 100 which is an example of an image forming apparatus provided with the decurling device 14 of the present invention.

  As shown in FIG. 1, the printer 100 includes a paper feed cassette 2 a serving as a paper storage unit disposed below the inside of the printer main body 1, and a manual paper feed tray 2 b provided outside the right side of the printer main body 1. ing. A sheet feeding device 3a is disposed downstream of the sheet feeding cassette 2a in the sheet conveying direction, that is, above the right side of the sheet feeding cassette 2a in FIG. Further, a sheet feeding device 3b is disposed downstream of the manual sheet feeding tray 2b in the sheet conveyance direction, that is, on the left side of the manual sheet feeding tray 2b in FIG. The paper P is separated and sent out one by one by the paper feeding devices 3a and 3b.

  Further, a first paper transport path 4a is provided inside the printer 100. The first paper transport path 4a is located to the upper right with respect to the paper feed cassette 2a, and to the left with respect to the manual paper feed tray 2b. The paper P sent from the paper feed cassette 2a passes through the first paper feed path 4a and moves vertically upward along the side surface of the printer body 1, and the paper sent from the manual feed tray 2b passes through the first paper feed path 4a. And is transported substantially horizontally to the left.

  A registration roller pair 13 is provided at the downstream end of the first paper transport path 4a in the paper transport direction. Further, a belt transport unit 5 and an ink jet recording unit 9 are disposed immediately downstream of the registration roller pair 13. The registration roller pair 13 corrects the oblique feeding of the sheet P, measures the timing with the ink discharge operation performed by the inkjet recording unit 9, and sends the sheet P toward the belt transport unit 5.

  The belt transport unit 5 includes an endless transport belt wound around a driving roller and a driven roller. The transport belt is rotated counterclockwise in FIG. 2 by the drive roller.

  The ink jet recording unit 9 is supported at a height such that a predetermined interval (for example, 1 mm) is formed with respect to the conveyance surface (upper surface) of the belt conveyance unit 5 and has a recording area equal to or larger than the width of the paper P. are doing. The ink jet recording unit 9 applies ink of each color corresponding to the information of the image data received from an external computer or the like to the paper P conveyed while being sucked and held on the conveyance surface of the belt conveyance unit 5, and the ink corresponding to the printing position. Discharge is performed from a discharge nozzle (not shown).

  A transport guide section 12 is arranged downstream (left side in FIG. 1) of the belt transport section 5 with respect to the paper transport direction. The paper P on which the ink image has been recorded in the inkjet recording unit 9 is sent to the transport guide unit 12, and the ink discharged to the surface of the paper P while passing through the transport guide unit 12 is dried.

  A decurling device 14 is provided downstream of the conveyance guide section 12 in the sheet conveyance direction and near the left side surface of the printer body 1. The paper P on which the ink has been dried in the transport guide unit 12 is sent to the decurling device 14, where the curl of the paper P is corrected (decurled).

  A second paper transport path 4b is provided downstream of the decurling device 14 in the paper transport direction (upward in FIG. 1). When the double-sided recording is not performed, the sheet P that has passed through the decurling device 14 is discharged from the second sheet conveying path 4b to a sheet discharge tray 15 provided outside the left side of the printer 100 via a pair of discharge rollers.

  Further, a maintenance unit 19 is arranged below the transport guide section 12. The maintenance unit 19 moves below the ink jet recording unit 9 and wipes ink that is forcibly ejected (purged) from the ink ejection nozzles in order to prevent clogging of the ink ejection nozzles of the recording head, and removes the wiped ink. to recover.

  Further, in the printer 100, a control unit (CPU) 50 for controlling operations of the above-described belt transport unit 5, the ink jet recording unit 9, the registration roller pair 13, the decurling device 14, the maintenance unit 19 and the like is arranged.

  FIG. 2 is an external perspective view of the decurling device 14 according to one embodiment of the present invention, FIG. 3 is a perspective view showing the internal structure of the decurling device 14 of this embodiment, and FIG. 4 is a decurling device 41 of this embodiment. FIG. 5 is a block diagram showing a driving mechanism of the decurling device 14 of the present embodiment. 3 and 4 show a state in which the frame 14a of the decurling device 14 has been removed. The decurling device 14 rotates around the driving roller 20 and the driven roller 21, rotates, and contacts a decurling belt 23 that contacts the back surface (non-image forming surface) of the paper P, and is pressed against the decurling belt 23 to contact the front surface of the paper P. It has a decurling roller 25 that comes into contact with the (image forming surface) and a pressing mechanism 27.

  In order to enhance the curl correcting effect of the decurling device 14, it is necessary to use a hard roller having a diameter as small as possible as the decurling roller 25. As the decal roller 25, for example, a metal roller having a diameter of 8 mm or less is used. On the other hand, a non-stretchable resin belt is used as the decal belt 23.

  The rotation shaft 20a of the drive roller 20 and the decal roller 25 are rotatably supported on the frame 14a via bearings (not shown). The rotating shaft 21a of the driven roller 21 is rotatably supported by the frame 14a, and is urged by the coil spring 28 of the pressing mechanism 27 in the direction in which the decal belt 23 winds around the decurling roller 25 (to the right in FIG. 4). I have. With this configuration, a nip portion N is formed by the decurling belt 23 and the decurling roller 25. The rotation shaft 21a of the driven roller 21 is supported movably along an arc trajectory around the decal roller 25 by the rotation of a link member 35 (see FIG. 6) to which the rotation shaft 21a is connected. The pressing mechanism 27 is swingably supported by the frame 14a with the support shaft 27a as a fulcrum.

  A roller drive motor 29 that rotationally drives the decal roller 25 is disposed on the frame 14a. A drive input gear 30 is fixed to a rotation shaft 20 a of the drive roller 20. The drive input gear 30 is connected to a belt drive motor 28 (see FIG. 5) that drives the drive roller 20 to rotate. That is, the decurling belt 23 and the decurling roller 25 rotate independently.

  6 and 7 are an external perspective view and a side view, respectively, of the decurling device 14 of the present embodiment and the transport guide portion 12 disposed upstream of the decurling device 14 in the sheet transport direction. The transport guide section 12 includes an upper guide plate 40 and a lower guide plate 41, and is disposed adjacent to the paper transport direction (the white arrow direction in FIGS. 6 and 7) on the upstream side of the decurling device 14. I have.

  The upper guide plate 40 is formed with a plurality of ribs 40a protruding toward the lower guide plate 41 along the paper transport direction and a plurality of slits 40b extending along the paper transport direction. The ribs 40a and the slits 40b reduce contact between the printing surface of the paper P and the upper guide plate 40. The lower guide plate 41 is formed longer in the transport direction than the upper guide plate 40, and the paper P on which the ink image is recorded in the inkjet recording unit 9 is transported along the lower guide plate 41. Thereafter, when the leading end of the paper P reaches the upper guide plate 40, the paper P is directed toward the nip portion N (see FIG. 4) of the decurling device 14 while being guided from above and below by the upper guide plate 40 and the lower guide plate 41. Conveyed.

  A first link pulley 31a is rotatably supported at one end of the rotation shaft 25a of the decal roller 25. The first link pulley 31a is rotatable independently of the decurling roller 25. A second link pulley 31b is rotatably supported below one end of the decal roller 25 in the axial direction (an end on the side where the first link pulley 31a is supported). A drive belt 33 is wound around the first link pulley 31a and the second link pulley 31b. A link drive motor 32 (see FIG. 5) is connected to the second link pulley 31b. One end of a link member 35 is fixed to the first link pulley 31a. The other end of the link member 35 is rotatably connected to the rotation shaft 21 a of the driven roller 21. The first link pulley 31a, the second link pulley 31b, the link drive motor 32, the drive belt 33, the link member 35, and the control unit 50 adjust the decurl amount by changing the position of the driven roller 21. 37.

  When the second link pulley 31b is rotationally driven in the counterclockwise direction in FIG. 7 by the link drive motor 32, a driving force is transmitted to the first link pulley 31a via the drive belt 33, and the first link pulley 31a is also counterclockwise. Rotate around. As a result, the link member 35 also rotates counterclockwise about the first link pulley 31a, and the rotation shaft 21a of the driven roller 21 connected to the rotation end of the link member 35 is centered on the decurling roller 25. Move counterclockwise on the circular orbit. At this time, the pressing mechanism 27 that presses the rotating shaft 21a also swings counterclockwise in FIG. 4 about the support shaft 27a following the movement of the rotating shaft 21a.

  FIG. 8 is a side view showing a change in the winding angle of the decal belt 23 with respect to the decur roller 25 as the driven roller 21 moves. 8, the position of the decurling belt 23 after the movement of the driven roller 21 is indicated by a broken line. When the driven roller 21 is moved counterclockwise around the decal roller 25, the winding angle of the decal belt 23 with respect to the decal roller 25 (nip width of the nip portion N) increases. On the other hand, when the driven roller 21 is moved clockwise, the winding angle of the decal belt 23 around the decurling roller 25 becomes smaller.

  Here, the fluctuation amount of the winding angle of the decal belt 23 is equal to the rotation angle θ of the straight line L passing through the rotation center of the decurling roller 25 and the driven roller 21. The decurling effect increases as the winding angle of the decal belt 23 around the decal roller 25 increases, and the decurling effect decreases as the winding angle of the decal belt 23 decreases.

  In the present embodiment, the wrap angle of the decal belt 23 around the decal roller 25 can be changed by changing the position of the driven roller 21 that stretches the decal belt 23 by the decurl amount adjustment mechanism 37.

  The nip width between the decurling belt 23 and the decurling roller 25 required for the curl correction varies depending on conditions such as the thickness of the sheet P, basis weight (basis weight), printing density (printing rate), and temperature and humidity. Therefore, in the control unit 50 (see FIG. 1), information on the thickness and basis weight (weight per unit area) of the paper P input from a higher-level device such as a personal computer or an operation panel (not shown) is acquired in the printer 100. It is preferable to set an appropriate wrap angle (nip width) of the decal belt 23 with respect to the decal roller 25 based on information on the print density (print ratio) and the temperature and humidity inside the apparatus. Specifically, a control signal based on the above information is transmitted from the control unit 50 to the link drive motor 32, and the control signal is transmitted so that the winding angle of the decal belt 23 with respect to the decurling roller 25 becomes a set value corresponding to the thickness of the sheet P. The position of the rotating shaft 21a of the driven roller 21 is adjusted by rotating the two-link pulley 31b by a predetermined amount.

  Thus, with a simple configuration without changing the roller diameters of the decal roller 25 and the driven roller 21, an appropriate decal amount according to the thickness, basis weight (basis weight), print density (print ratio), and temperature and humidity of the paper P can be obtained. It is possible to effectively suppress the problem that the amount of decurl is excessive when the paper P is thick paper and wrinkles are generated, and the decurl amount is insufficient when the paper P is thin paper. . Further, since the position of the driven roller 21 is changed around the rotation axis of the decurling roller 25, the positional relationship between the driving roller 20 and the decurling roller 25 does not change. Therefore, even when the non-stretchable decal belt 23 is used, the winding angle of the decal belt 23 with respect to the decal roller 25 can be changed while the contact state between the decal belt 23 and the decal roller 25 is always maintained.

  Next, a description will be given of a change in the posture of the transport guide unit 12 accompanying a change in the nip width of the decurling device 14. FIG. 9 is a side cross-sectional view of the decurling device 14 of the present embodiment and the transport guide portion 12 disposed upstream of the decurling device 14 in the sheet transport direction. The second link pulley 31b (see FIG. 6) is fixed to a guide elevating shaft 43, and a guide elevating plate 45 is fixed to the guide elevating shaft 43. The guide elevating shaft 43 also serves as a rotation shaft of the second link pulley 31b. The guide elevating shaft 43 and the guide elevating plate 45 constitute an angle adjusting mechanism 47 for adjusting the attitude (angle) of the upper guide plate 40 and the lower guide plate 41.

  When the second link pulley 31b is driven to rotate counterclockwise, the guide lifting shaft 43 and the guide lifting plate 45 also rotate counterclockwise. As a result, the guide elevating plate 45 pushes up the lower surface of the lower guide plate 41 so that the lower guide plate 41 and the upper guide plate 40 fixed to the lower guide plate 41 rotate clockwise about the guide plate swing shaft 49 as a fulcrum. Rocks. That is, the downstream end portions of the upper guide plate 40 and the lower guide plate 41 move upward with respect to the sheet transport direction.

  As shown in FIG. 8, when the winding angle of the decal belt 23 around the decurling roller 25 is increased, the driven roller 21 moves upward. Then, as the driven roller 21 moves, the path of the sheet P entering the nip portion N also moves upward. In the present embodiment, the downstream ends of the upper guide plate 40 and the lower guide plate 41 also move upward with the movement of the driven roller 21. Therefore, since the angle of the conveyance guide portion 12 is adjusted according to a change in the path of the sheet P entering the nip portion N due to the change in the decurling amount, it is possible to smoothly guide the sheet P to the nip portion N of the decurling device 14. Can be.

  In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the drive belt 33 is stretched by the first link pulley 31a and the second link pulley 31b, but the drive belt 33 may be stretched by three or more link pulleys. Further, in the above embodiment, the guide elevating shaft 43 is also used as the rotation shaft of the second link pulley 31b, but the guide elevating shaft 43 may be connected to the second link pulley 31b via a gear.

  In the above-described embodiment, the drive belt 33 is used as a drive force transmitting member that transmits the rotational drive force of the second link pulley 31b to the first link pulley 31a. A gear train that connects the pulley 31a and the second link pulley 31b may be used.

  Further, in the above-described embodiment, the inkjet recording type printer 100 including the decurling device 14 has been described as an example. However, the decal device of the present invention is not limited to the inkjet recording type, and may be an electrophotographic copying machine. The present invention can be applied to other image forming apparatuses such as a printer, a multifunction peripheral, a facsimile, and the like.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a decurling device that corrects curl by inserting a sheet-shaped recording medium through a nip between a decal roller and a belt. By using the present invention, it is possible to provide a decurling apparatus having a simple configuration capable of appropriately finely adjusting the decurling amount, and an image forming apparatus including the decurling apparatus.

9 Inkjet recording unit (image forming unit)
Reference Signs List 12 transport guide section 14 decurling device 14a frame 20 drive roller 20a rotating shaft (drive roller)
21 driven roller 21a rotating shaft (driven roller)
23 Decal belt 25 Decal roller 25a Rotary axis (Decal roller)
27 Pressing mechanism 27a Support shaft 28 Belt drive motor 29 Roller drive motor 31a First link pulley 31b Second link pulley 32 Link drive motor (link drive unit)
33 drive belt (drive force transmission member)
35 Link member 37 Decal amount adjusting mechanism 40 Upper guide plate 41 Lower guide plate 43 Guide elevating shaft 45 Guide elevating plate 47 Angle adjusting mechanism 50 Control unit 100 Printer (image forming apparatus)
P paper (recording medium)

Claims (7)

An endless decal belt that is wrapped around a drive roller and a driven roller and contacts a non-image forming surface of a recording medium;
A decal roller that contacts the outer peripheral surface of the decal belt to form a nip portion and contacts an image forming surface of a recording medium;
And a pressing mechanism for urging the driven roller in a direction to press the decal belt against the decal roller,
In a decurling device that corrects curl of a recording medium by inserting a sheet-shaped recording medium through the nip portion,
A decurling device comprising a decurling amount adjusting mechanism for adjusting a nip width of the nip portion by changing a position of the driven roller about a rotation axis of the decurling roller. The decal amount adjustment mechanism,
A pair of link pulleys including a first link pulley provided coaxially with the decal roller and rotatable independently of the decal roller, and a second link pulley to which a rotational driving force is input;
A driving force transmitting member that transmits a rotational driving force from the second link pulley to the first link pulley;
A link member having one end fixed to the first link pulley and the other end rotatably connected to a rotation shaft of the driven roller;
A link driving unit that inputs a rotational driving force to the second link pulley;
A control unit that controls driving of the link driving unit;
Has,
The control unit rotates the first link pulley by a predetermined amount via the second link pulley and the driving force transmitting member by the link driving unit, thereby centering the first link pulley via the link member. The decurling apparatus according to claim 1, wherein the driven roller is moved by a predetermined amount along a circular orbit.   The pressing mechanism is supported swingably around a spindle provided on the upstream side in the biasing direction of the driven roller, and the driven roller moves on an arc track centered on the decal roller. The decurling device according to claim 2, wherein the pressing mechanism swings. A decurling device according to any one of claims 1 to 3,
A transport guide unit configured by an upper guide plate and a lower guide plate disposed on the upstream side of the decurling device with respect to the transport direction of the recording medium, and guiding the recording medium to the nip portion,
An image forming unit that is provided on the upstream side of the conveyance guide unit with respect to the conveyance direction of the recording medium and forms an image on the recording medium;
Has,
The upper guide plate and the lower guide plate are fixed at a predetermined distance, and the downstream end can swing up and down around a guide plate rotation shaft provided on the upstream side in the conveyance direction of the recording medium. An image forming apparatus, wherein the image forming apparatus is supported by an image forming apparatus.   The image forming apparatus according to claim 4, further comprising an angle adjustment mechanism that adjusts an angle between the upper guide plate and the lower guide plate in accordance with movement of the driven roller by the decurl amount adjustment mechanism. A decurling device according to claim 2 or claim 3,
A transport guide unit configured by an upper guide plate and a lower guide plate disposed on the upstream side of the decurling device with respect to the transport direction of the recording medium, and guiding the recording medium to the nip portion,
An image forming unit that is provided on the upstream side of the conveyance guide unit with respect to the conveyance direction of the recording medium and forms an image on the recording medium;
Has,
The upper guide plate and the lower guide plate are fixed at a predetermined distance, and the downstream end can swing up and down around a guide plate rotation shaft provided on the upstream side in the conveyance direction of the recording medium. Supported by
Providing an angle adjustment mechanism for adjusting the angle of the upper guide plate and the lower guide plate in accordance with the movement of the driven roller by the decurl amount adjustment mechanism,
The angle adjustment mechanism,
A guide elevating shaft fixed to the second link pulley or connected via a gear train;
A guide elevating plate fixed to the guide elevating shaft,
In images forming device characterized in that it is configured.   The image forming apparatus according to claim 4, wherein the image forming unit is an ink jet recording unit that forms an image by ejecting a liquid ink on a recording medium.

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