JP5444775B2 - Curl correction device and image forming apparatus - Google Patents

Description

  The present invention relates to a curl correction apparatus and an image forming apparatus including the same.

  Patent Document 1 describes a curl correction apparatus that conveys a sheet member while correcting the curl of the sheet member (recording medium).

  Specifically, the curl correcting device includes two rolls, a belt wound around the two rolls, and a pressing roll that rotates following the belt.

  Then, the sheet member is nipped and conveyed by the pressing roll and the belt, and the position of the driven roll is changed according to the degree of curvature generated in the sheet member.

  That is, by changing the position of the pressing roll according to the curl degree of curl, correction is made according to the degree of curl produced in the sheet member.

JP-A-6-144678

  An object of the present invention is to effectively correct curls having different degrees of curvature that occur in a recording medium.

The curl correction device according to claim 1 of the present invention is arranged to be rotationally driven and elastically deformable drive members and a plurality of adjacent drive members along the conveyance path of the recording medium, elastically deform the drive members, Curvature application of the curvature application roll group based on at least one of the information on the paper type of the recording medium conveyed along the conveyance path and the information on the degree of curl of the curl. And a variable means for moving the roll separately and changing the curvature of the outer peripheral surface of the drive member by elastically deforming the drive member.

  The curl correction apparatus according to a second aspect of the present invention is the curl correction device according to the first aspect, wherein the variable means includes a support member that supports an end portion of the curvature applying roll, an end portion fixed to the support member, and the conveyance A shaft member extending in a direction intersecting the path; and a movable member configured to move the shaft member in an extending direction of the shaft member and change a curvature of an outer peripheral surface of the drive member.

  The curl correction apparatus according to a third aspect of the present invention is characterized in that, in the first or second aspect, a plurality of the curvature imparting roll groups are provided in a direction intersecting the transport path.

  The curl correction apparatus according to a fourth aspect of the present invention is the curl correction device according to the second or third aspect, wherein the movable member is capable of being transmitted to the gear member for transmitting a movable force for moving the shaft member to the shaft member. And a stepping motor for applying power.

  An image forming apparatus according to a fifth aspect of the present invention is provided with a fixing device that fixes a toner image transferred to a recording medium to a recording medium by a heat fixing method, and a downstream of the fixing device in a recording medium conveyance direction, 5. A curl amount detection unit that detects a curl amount of a recording medium; a curl correction device according to claim 1 provided downstream of the curl amount detection unit in a recording medium conveyance direction; and the curl. Control means for operating the variable means to move the curvature applying roll based on the curl amount of the recording medium detected by the quantity detection means, and changing the curvature of the outer peripheral surface of the drive member. And

  According to the curl correcting apparatus of the first aspect of the present invention, it is possible to give various curvatures to the recording medium for each part along the transport direction as compared with the case where the present configuration is not provided.

  According to the curl straightening device of the second aspect of the present invention, the curvature applying roll can be moved with a simple configuration as compared with the case without this configuration.

  According to the curl correcting apparatus of the third aspect of the present invention, curling in the direction intersecting the transport path can be corrected effectively as compared with the case without this configuration.

  According to the curl straightening device of the fourth aspect of the present invention, the curvature applying roll can be stopped with higher accuracy than when the stepping motor is not used.

  According to the image forming apparatus of the fifth aspect of the present invention, it is possible to effectively correct the curl having a different degree of curvature generated in the recording medium as compared with the case where this configuration is not provided.

It is the side view which showed the curl correction apparatus which concerns on 1st Embodiment of this invention, and its peripheral member. It is the side view which showed the curl correction apparatus which concerns on 1st Embodiment of this invention. (A) (B) It is the side view which showed the curl correction apparatus which concerns on 1st Embodiment of this invention. It is the perspective view which showed the curl correction apparatus which concerns on 1st Embodiment of this invention. 1 is a schematic configuration diagram illustrating an image forming apparatus in which a curl correction apparatus according to a first embodiment of the present invention is employed. It is the perspective view which showed the curl correction apparatus which concerns on 2nd Embodiment of this invention. (A) (B) It is the front view which showed the curl correction apparatus which concerns on 2nd Embodiment of this invention. It is the expansion perspective view which showed the curl correction apparatus which concerns on 2nd Embodiment of this invention.

  An image forming apparatus employing an example of a curl correction apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

(overall structure)
As shown in FIG. 5, the image forming apparatus 10 includes a housing 12 as a casing, and a developing device 24Y that forms a yellow toner image in the housing 12, a developing device 24M that forms a magenta toner image, and cyan. A developing device 24C for forming the toner image and a developing device 24K for forming the black toner image are arranged in the vertical direction in order from the top. In addition, when it is necessary to distinguish YMCK, it demonstrates by attaching | subjecting any of Y, M, C, K after a code | symbol, and when it is not necessary to distinguish YMCK, YMCK is abbreviate | omitted.

  On the other hand, the photosensitive member cartridge 18 disposed above the developing unit 24 includes a drum-shaped photosensitive member 22 and a charging roll 26 that charges the surface of the photosensitive member 22. Further, an optical scanning device 14 corresponding to each color for exposing the surface of the photoconductor 22 to form an electrostatic latent image is disposed adjacent to the photoconductor cartridge 18.

  Further, the developing rolls 20 provided in the developing devices 24Y, 24M, 24C, and 24K convert the electrostatic latent image on the photosensitive member 22 to yellow (Y), magenta (M), cyan (C), and black (K), respectively. Visualize by developing with toner.

  Further, a transfer roll 30 for transferring the toner image on the photosensitive member 22 to the sheet member P is disposed to face the photosensitive member 22, and constitutes an image forming unit 44.

  On the other hand, a paper feed cassette 16 that accommodates a sheet member P as a recording medium is provided at a lower portion in the housing 12. The paper feed cassette 16 is provided with a feed roll 32 that feeds the sheet member P at a predetermined timing, and a conveyance path 28 of the sheet member P located between the feed roll 32 and the developing device 24K has a nip. A conveyance roll 34 is provided, and an optical sheet member passage sensor 36 is disposed downstream of the nip conveyance roll 34 in the sheet member conveyance direction. The sheet member passage sensor 36 detects the leading end of the sheet member P, and the timing of writing the electrostatic latent image of each optical scanning device 14 is controlled based on the detection timing.

  Further, a fixing device 38 for fixing the toner image to the sheet member P by heating and press-bonding is provided in the transport path 28 located on the downstream side of the developing device 24Y. Inside the housing of the fixing device 38, a fixing device 38 is provided. Are provided with a heating roll 38A having a built-in heater and a pressure roll 38B for pressing the sheet member P against the heating roll 38A.

  A guide member 48 for guiding the sheet member P in the discharge direction is provided on the downstream side of the fixing device 38, and further, the sheet member P curled in a curved shape by the fixing device 38 is corrected downstream of the guide member 48. A curl correction device 50 is provided. Further, a discharge roll 40 for discharge is provided on the downstream side of the curl correction device 50, and the sheet member P on which the toner image is fixed is guided to the discharge roll 40 and formed on the upper surface of the housing 12. It is discharged to the tray 42. The details of the curl correction apparatus 50 will be described later.

  In the image forming apparatus 10 configured as described above, an image is formed as follows.

  First, the charging roll 26 to which a voltage is applied uniformly negatively charges the surface of the photosensitive member 22 with a predetermined charged portion potential.

  Subsequently, exposure is performed by the optical scanning device 14 so that an image portion on the charged photosensitive member 22 has a predetermined exposure portion potential, and an electrostatic latent image is formed.

  That is, an electrostatic latent image corresponding to the image information is formed on the photosensitive member 22 by turning on and off the laser emitted from the optical scanning device 14 based on image information supplied from a control device (not shown).

  A developing bias set in advance for each color is applied to the developing roll 20 of the developing unit 24, and the electrostatic latent image is developed with toner when passing through the position of the developing roll 20, and visualized as a toner image. The

  Therefore, the sheet member P passes through the image forming unit 44 between the photoreceptor 22 and the transfer roll 30, and the toner image is transferred to the sheet member P. The transferred toner image is heat-pressed and fixed on the sheet member P by being nipped and conveyed between a heating roll 38A and a pressure roll 38B provided in the fixing device 38.

  Further, the sheet member P on which the toner image is fixed is guided by the guide member 48, conveyed by the curl correction device 50 and the discharge roll 40, and discharged to the discharge tray 42 formed on the upper surface of the housing 12.

(Main part configuration)
Next, the curl correction apparatus 50 will be described.

  As shown in FIGS. 2 and 4, the curl straightening device 50 is provided with a drive roll 52 as a drive member that rotates and conveys the sheet member P. The drive roll 52 of the present embodiment has a diameter of 26 mm and is formed of an elastic member such as a rubber member so as to be elastically deformable. The diameter of the drive roll 52 is appropriately selected according to the size of the entire apparatus.

  Specifically, the drive roll 52 is rotatably supported by a frame member (not shown), and is rotated by a rotational force of a motor (not shown) being transmitted.

  Furthermore, the sheet member P is provided so as to be driven to rotate with the driving roll 52, and the sheet member P is sandwiched and conveyed between the driving roll 52, thereby curling the sheet member P (the sheet member P is rounded during or after printing). A curvature imparting roll group 55 is provided to correct the phenomenon.

  Specifically, the curvature imparting roll group 55 includes four curvature imparting rolls 54 provided adjacent to each other along the conveying direction of the sheet member P, and the curvature imparting roll 54 has a diameter of 2 mm. However, it is not limited to this, and may be 8 mm or less.

  Further, both ends of the curvature applying roll 54 are rotatably supported by a bracket 56, and one end of a cylindrical shaft member 60 is fixed to one end of the bracket 56 (the upper end shown in FIGS. 2 and 4). The shaft member 60 extends in a direction intersecting the conveyance path 28 that conveys the sheet member P (in the present embodiment, upward in FIGS. 2 and 4).

  A thick plate-like frame member 58 that supports the shaft member 60 is provided on the other end side of the shaft member 60 so that the shaft member 60 can move in the extending direction. Further, a helical screw portion 60A is formed on the outer peripheral surface of the shaft member 60, and a gear member 62 having a screw portion 62A that engages with the screw portion 60A is provided on the outer periphery. A rotating shaft 68 of a stepping motor 66 fixed to a flat frame plate 64 is fixed at the center of the gear member 62.

  With this configuration, by applying a predetermined pulse voltage to each stepping motor 66, the rotation shaft 68 and the gear member 62 of the stepping motor 66 are rotated by a predetermined angle. As a result, the shaft member 60 moves by a predetermined amount in the extending direction of the shaft member 60, and the outer surface 70 of the drive roll 52 is determined by elastically deforming the drive roll 52 as shown in FIG. Change to curvature.

  On the other hand, as shown in FIG. 1, a curl detection member 80 as a curl detection means such as a photosensor is provided downstream of the fixing device 38 (see FIG. 5). Specifically, the curl detecting member 80 measures the position of the leading end portion of the sheet member P on which the toner image is fixed by the fixing device 38, and detects the degree of curl generated on the sheet member P. ing.

  Further, the image forming apparatus 10 has each stepping motor 66 in accordance with the curl degree detected by the curl detection member 80 and the type of the sheet member P (plain paper, cardboard, etc.) set by the user. A control unit 78 is provided that applies a pulse voltage, rotates the gear member 62, and moves the shaft member 60 in the extending direction.

(Function)
As shown in FIG. 5, the sheet member P on which the toner image is formed on the surface through the image forming unit 44 between the photosensitive member 22 and the transfer roll 30 is conveyed to the fixing device 38. In the fixing device 38, the sheet member P is nipped and conveyed between the heating roll 38 </ b> A and the pressure roll 38 </ b> B, and the toner image is heat-pressed and fixed on the sheet member P.

  Here, the sheet member P may be deformed (curled) into a curved shape due to evaporation of moisture contained in the sheet member P due to the heat of the heating roll 38A.

  As shown in FIG. 1, the curl detection member 80 detects the degree of curl generated in the sheet member P sent out from the fixing device 38 and transmits this information to the control unit 78.

  Further, the controller 78 applies a pulse voltage to the stepping motor 66 according to the curl degree transmitted from the curl detection member 80 and the type of the sheet member P (plain paper, cardboard, etc.) set by the user, The gear member 62 is rotated and the shaft member 60 is moved in the extending direction.

  For example, when the degree of curl of plain paper is small (curvature is small), as shown in FIG. 3A, the four shaft members 60 are moved in the stretching direction. Then, the driving roll 52 is elastically deformed by the curvature applying rolls 54 respectively provided at the lower ends of the four shaft members 60, and the curvature of the outer surface 70 of the driving roll 52 is reduced to weaken the curl correction ability.

  In this state, by curling the sheet member P deformed into a curved shape along the conveyance path 28 formed between the curvature applying roll 54 and the drive roll 52, the curl with a small degree of curvature generated in the sheet member P is corrected. Is done.

  On the other hand, when the curl degree of curl is large (large curvature) in the thick paper, the four shaft members 60 are moved in the stretching direction as shown in FIG. Then, only the curvature imparting roll 54 (in the present embodiment, the second curvature imparting roll 54 from the right shown on the paper surface) provided at the lower end of one shaft member 60 is pressed so as to bite into the drive roll 52. By pressing only one curvature imparting roll 54 into the drive roll 52, the drive roll 52 is elastically deformed locally, and the curvature of the outer surface 70 of the drive roll 52 is increased to enhance the curl correction ability. .

  In this state, by curling the sheet member P deformed into a curved shape along the conveyance path 28 formed between the curvature applying roll 54 and the driving roll 52, the curl with a large degree of curvature generated in the sheet member P is corrected. Is done.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is clear to the contractor. For example, in the above-described embodiment, the curl generated in the sheet member P is corrected using the four curvature imparting rolls 54 provided in the curvature imparting roll group 55, but is not particularly limited to four, Two or three may be sufficient, and five or more may be sufficient.

  In the above-described embodiment, the control unit 78 changes the curvature of the outer surface 70 based on the curl degree of the sheet member P and whether the sheet member P is plain paper or cardboard. The curvature of the sheet member conveyance surface may be changed based on the basis weight of the sheet member P and the like.

  In the above-described embodiment, the curl correction apparatus 50 is used for the image forming apparatus 10. However, any other apparatus may be used as long as the apparatus can convey a sheet member, and the present invention is not particularly limited to the image forming apparatus.

  In the above embodiment, the stepping motor 66 is used to move the shaft member 60 in the extending direction. However, the stepping motor 66 is not particularly limited, and the moving force can be transmitted to the shaft member 60. Anything is possible.

  Next, an image forming apparatus employing an example of a curl correction apparatus according to a second embodiment of the present invention will be described with reference to FIGS.

  In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 6, in the second embodiment, unlike the first embodiment, there are four curvature imparting rolls 102 provided in the curvature imparting roll group 101 of the curl correcting device 100 along the conveyance path of the sheet member P. Three are provided in a direction intersecting the conveyance path (a direction orthogonal in the present embodiment).

  As shown in FIG. 8, both ends of the curvature imparting roll 102 are rotatably supported by a U-shaped bracket 104 having an open bottom, and one end of the bracket 104 (upper end shown in FIG. 8) One end of the cylindrical shaft member 106 is fixed, and this shaft member 106 extends in a direction intersecting with the conveyance path for conveying the sheet member P (upper direction shown in FIG. 8 in this embodiment).

  Further, on the other end side of the shaft member 106, a thick plate-like frame member 118 that supports the shaft member 106 is provided so that the shaft member 106 can move in the extending direction. Further, a helical screw portion 106A is formed on the outer peripheral surface of the shaft member 106, and a gear member 108 having a screw portion 108A that engages with the screw portion 106A is provided on the outer periphery.

  In addition, a rotation shaft 114 of a stepping motor 112 fixed to a flat frame plate 110 is fixed to the center portion of the gear member 108.

  With this configuration, as shown in FIG. 7, when curling occurs in the direction intersecting the conveyance path of the sheet member P, the curvature applying roll 102 disposed in the center portion as viewed from the sheet member conveyance direction is provided. Pressing the drive roll 52 so as to bite into the drive roll 52 (see FIG. 7A), or pressing the curvature imparting rolls 102 disposed at both ends as seen from the sheet member conveying direction into the drive roll 52 (see FIG. 7). (B)), the curl generated in the direction intersecting the conveyance path of the sheet member P is corrected.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is clear to the contractor. For example, in the above-described embodiment, three rows of the curvature imparting rolls 102 are provided in the direction intersecting the conveyance path. However, the number is not particularly limited to three rows, and may be two rows, or four or more rows. It may be.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 28 Conveyance path 38 Fixing apparatus 50 Curl correction apparatus 52 Drive roll (drive member)
54 Curvature imparting roll 55 Curvature imparting roll group 56 Bracket (supporting member)
60 Shaft member 62 Gear member 66 Stepping motor 70 Outer surface 78 Control unit 80 Curl detection member (curl detection means)
DESCRIPTION OF SYMBOLS 100 Curl correction apparatus 101 Curvature provision roll group 102 Curvature provision roll 104 Bracket (support member)
106 Shaft member 108 Gear member 112 Stepping motor

Claims (5)

A drive member that is rotationally driven and elastically deformable;
A plurality of adjacently disposed recording media along the conveyance path of the recording medium, elastically deforming the drive member, and a group of curvature imparting rolls that rotate following the drive member;
Based on at least one of the information on the paper type of the recording medium conveyed along the conveyance path and the information on the degree of curl of the curl, the curvature imparting rolls of the curvature imparting roll group are individually moved, and the drive member is elastically operated. Variable means for changing the curvature of the outer peripheral surface of the drive member by deforming,
A curl straightening device. The variable means is
A support member for supporting an end of the curvature applying roll;
A shaft member having an end fixed to the support member and extending in a direction intersecting the transport path;
A movable member that moves the shaft member in the extending direction of the shaft member and changes the curvature of the outer peripheral surface of the drive member;
The curl correction apparatus according to claim 1.   The curl correction apparatus according to claim 1, wherein a plurality of the curvature imparting roll groups are provided in a direction intersecting the transport path. The movable member is
A gear member for transmitting a movable force for moving the shaft member to the shaft member;
A stepping motor that applies a movable force to the gear member;
The curl correction apparatus according to claim 2 or 3. A fixing device for fixing the toner image transferred to the recording medium to the recording medium by a heat fixing method;
A curl amount detection means provided downstream of the fixing device in the recording medium conveyance direction for detecting the curl amount of the recording medium;
The curl correction apparatus according to any one of claims 1 to 4, which is provided downstream of the curl amount detection unit in a recording medium conveyance direction;
Based on the curl amount of the recording medium detected by the curl amount detection means, the control means for operating the variable means to move the curvature applying roll and changing the curvature of the outer peripheral surface of the drive member;
An image forming apparatus comprising:

Images