JP2007022756A - Paper correction device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper correction device reducing an installation space while having a cooling function, and also to provide an image formation device equipped with the paper correction device. <P>SOLUTION: This paper correction device is provided with: a circulating belt 151d moving on a predetermined circulation path and running together with paper on part of the circulation path; a press cylinder 151e having a hollow and cylindrical shape and pressing paper running together with the circulating belt 151d against the circulating belt 151d on the cylindrical peripheral face to flex the circulating belt 151d together with the paper; and a first blast part 151a sending cooling air from an end part of the press cylinder 151e to inside of the press cylinder 151e. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper straightening device that corrects warp deformation of a paper, and an image forming apparatus that includes such a paper straightening device.

  In recent years, electrophotographic image forming apparatuses that form a toner image on a sheet based on image data representing an image and fix the toner image on the sheet by pressurizing and heating the sheet have become widespread.

  In such an image forming apparatus, the paper may be warped in a direction in which the image side is concave due to heat applied to the paper when the toner image is fixed. Such deformed paper is unsightly and inconvenient to handle.

  In view of this, an image forming apparatus including a sheet correction device that corrects the warp deformation of the sheet after fixing the toner image has been proposed (see Patent Document 1).

  FIG. 7 is a diagram illustrating an example of a sheet correction device.

  A sheet correction apparatus 500 shown in FIG. 7 corrects a warp deformation that has occurred on a sheet during fixing of a toner image, and includes a correction mechanism 510 as follows.

  The correction mechanism 510 includes a circulation belt 501, two tension rolls 502 that move along a predetermined circulation path while stretching the circulation belt 501, and run along with the paper in a part of the circulation path, and the circulation belt. A push cylinder 503 is provided that presses the paper running along with the paper 501 against the circulation belt 501 and flexes the circulation belt 501 and the paper together. In the correction mechanism 510, as shown in FIG. 7, the sheet is corrected by being bent in the direction opposite to the warp deformation.

  Here, in the image forming apparatus, for example, as shown in FIG. 7, the warped paper sheet may be carried with the concave side up, or conversely, the concave side may be carried down. For this reason, the sheet correction apparatus 500 shown in FIG. 7 uses the correction mechanism 510 as described above with a mirror surface arrangement in which sheets parallel to the circulation belt 501 of each correction mechanism 510 are parallel to each other in the same direction. Has set. In the example of FIG. 7, the sheet P1 conveyed with the concave side up is guided to the upper correction mechanism 510, and the sheet P2 conveyed with the concave side down is corrected on the lower side. Guided to mechanism 510. As a result, the sheet is always bent by the push tube 503 in the direction opposite to the warp deformation, and the sheet is appropriately corrected.

  Here, as described above, in the image forming apparatus, the sheet is often warped at the time of fixing, and such a sheet is generally heated. For this reason, there is a high possibility that the paper is still heated even after the warp deformation is corrected. When such heated paper cools, the toner on the paper contracts, and the paper once warped and deformed may be warped again in a direction in which the image side is concave.

  In view of this, a paper straightening device including a blower that blows cooling air toward the paper during correction of warp deformation has been proposed (see Patent Document 2).

  FIG. 8 is a diagram illustrating an example of a paper correction device with a blower.

FIG. 8 shows a paper straightening device 600 with a blower provided with two sets of a straightening mechanism 610 with a blower having a blower 601 that blows cooling air from the push tube 503 side to the nip portion 504 of the straightening mechanism 510 same as FIG. It is shown. Cooling air is blown from the blower 601 to the paper P passing through the nip portion 504. As a result, the warp deformation is corrected and the paper is cooled, so that re-deformation after correction is prevented.
JP-A-4-338060 JP-A-5-341601

  Here, in the paper straightening device 600 with a blower shown in FIG. 8, even if the warped paper is carried to the paper straightening device 600 with a blower with the concave side up, it is carried with the concave side down. As in the paper straightening device 500 in FIG. 7, the two blower-equipped straightening mechanisms 610 are arranged on the mirror surface so as to appropriately correct the warp deformation. However, a large space is required to arrange the two correction mechanisms 610 with a blower so that the blowers 601 of the correction mechanisms 610 with each blower do not collide with each other, and an image including such a paper correction device 600 with a blower is provided. The size of the forming apparatus will be increased.

  In addition, heretofore, a sheet correction apparatus provided with two correction mechanisms that are arranged on the mirror surface of each other has been described. Here, some image forming apparatuses are of a type that forms and fixes a toner image on one side of a sheet, and outputs the sheet without changing the orientation of the toner image side. In such a type of image forming apparatus, since the direction of the concave side of the warped paper is limited to either the top or bottom, one correction mechanism can be used as the paper correction device. Thus, even when only one correction mechanism is provided, a large space is required to install the sheet correction apparatus in the image forming apparatus so that the blower included in the correction mechanism does not collide with surrounding components.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a sheet correction device that has a cooling function and has a small installation space, and an image forming apparatus that includes such a sheet correction device.

The paper straightening device of the present invention that achieves the above object is a paper straightening device that corrects warp deformation of paper.
A circulating belt that moves along a predetermined circulation path and runs along with the paper in a part of the circulation path;
A push cylinder that has a hollow round cylindrical shape and presses the paper running along with the circulation belt against the circulation belt to bend the circulation belt and the paper together on the cylindrical peripheral surface;
And a first air blowing section for feeding cooling air into the inside of the push cylinder from the end of the push cylinder.

  According to the paper correction device of the present invention, the push tube presses the paper against the circulation belt and bends the circulation belt and the paper together. For this reason, the warp deformation of the paper can be corrected by passing the warped paper between the push tube and the circulation belt so as to bend in a direction opposite to the warp deformation. At this time, the cooling air from the first air blower passes through the inside of the push tube and reaches the side of the paper to cool the paper. That is, in the sheet correction apparatus of the present invention, the first air blowing unit for cooling the sheet does not need to be in the vicinity of the sheet, and the degree of freedom in arrangement is high. That is, according to the sheet correction device of the present invention, the first air blowing section can be arranged at an appropriate position, and the installation space of the entire sheet correction device can be reduced.

  Here, in the paper straightening device of the present invention, the form that “the push tube has a plurality of holes through which the cooling air sent into the inside by the first blower part is opened” is preferable. It is a form.

  According to this preferred embodiment of the paper straightening device, the cooling air that has escaped from the plurality of holes formed in the push tube is directly blown onto the paper that passes between the push tube and the circulation belt. Thereby, the cooling effect with respect to a paper can be heightened.

Further, in the paper straightening device of the present invention, “the circulation belt has a plurality of holes,
A configuration in which a second air blowing section that blows cooling air from the opposite side of the push tube toward the circulation belt is provided is also a preferable mode.

  According to this preferred embodiment of the paper straightening device, the cooling air sent from the second blower passes through the hole formed in the circulation belt and passes between the push tube and the circulation belt. Be sprayed on. As a result, the paper is cooled not only from the push tube side but also from the opposite side, so the cooling effect on the paper is high.

In the sheet correction device of the present invention, “a set of the circulation belt, the push tube, and the first air blowing unit is a mirror surface object in which the sheets running along with the circulation belt of each set are parallel to each other in the same direction. With multiple sets, and
It is also preferable that the apparatus includes a guide unit that guides the paper to a set corresponding to the direction of warp deformation of the paper among the plurality of sets.

  According to this preferred embodiment of the paper straightening device, even if the warped paper is carried with the concave side up, or conversely, the paper is made concave by the guide portion. It is guided to the set according to the direction of the warp deformation that the side is facing up or down. As a result, even when the warped paper is carried in the concave side up or down, the warp deformation of the paper is appropriately corrected.

An image forming apparatus of the present invention that achieves the above object includes a toner image forming unit that forms a toner image on a sheet based on image data representing an image;
A fixing unit for fixing the toner image on the paper by pressurizing and heating the paper on which the toner image is formed by the toner image forming unit;
A circulation belt that moves along a predetermined circulation path and runs along with the paper that has passed through the fixing unit in a part of the circulation path;
A hollow cylinder having a hollow round cylindrical shape, and a cylindrical cylinder that presses the paper running along with the circulation belt against the circulation belt to bend the circulation belt and the paper together.
And a first air blowing section for sending cooling air into the inside of the push cylinder from the end of the push cylinder.

  According to the image forming apparatus of the present invention, the deformation of the sheet sent from the fixing unit is the same as that of the sheet correcting apparatus in which space saving is achieved, and the circulation belt, the push tube, and the first are described above. The sheet is corrected by being set with the blower unit 1, and the sheet is cooled during the correction to prevent re-deformation after the correction.

  Note that the image forming apparatus of the present invention is only shown in its basic form here, but this is only for avoiding duplication, and the image forming apparatus of the present invention includes the above-described sheet correction apparatus. Various forms corresponding to each form are included.

  As described above, according to the present invention, it is possible to provide a sheet straightening device having a cooling function and a small installation space, and an image forming apparatus including such a sheet straightening device.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a first embodiment of the present invention will be described.

  FIG. 1 is a diagram showing an image forming apparatus according to a first embodiment of the present invention on which the first embodiment of the sheet correction apparatus according to the present invention is mounted.

  The image forming apparatus 10 illustrated in FIG. 1 includes a paper feeding device 110, a developing device 120, a fixing device 130, a paper straightening device 150, a discharge roll 160, and a paper discharge unit 170. In addition, a plurality of transport rolls 180 are disposed between the elements, and the plurality of transport rolls 180 form a paper transport path. Here, the sheet correction apparatus 150 corresponds to the first embodiment of the sheet correction apparatus of the present invention. The developing device 120 and the fixing device 130 correspond to examples of the toner image forming portion and the fixing portion, respectively, according to the present invention.

  Hereinafter, an outline of image formation in the image forming apparatus 10 will be described.

  The paper feeding device 110 accommodates a plurality of papers P therein, and sends the papers P to the transport path appropriately one by one. A pickup roll 111, a feed roll 112, and a retard roll 113 are provided. I have. First, the pick-up roll 111 picks up the sheet P by applying a force to the sheet P stacked on the top of the plurality of sheets P so that the sheet P goes out of the sheet feeding device 110. The feed roll 112 and the retard roll 113 are arranged to face each other and rotate in opposite directions. The feed roll 112 rotates in a direction to send out the paper P picked up by the pickup roll 111 to the outside of the paper feeding device 110. The retard roll 113 rotates in a direction opposite to that of the feed roll 112, and when a plurality of sheets P are picked up due to friction between sheets or the like, a sheet feeding device supplies a sheet P other than the uppermost sheet P. It serves to push back into 110. With the feed roll 112 and the retard roll 113, only the uppermost sheet is fed out of the paper feeding device 110.

  The sheet fed out of the sheet feeding device 110 is transported to the developing device 120 by a plurality of transport rolls 180. In the developing device 120, a toner image is formed on the surface of the intermediate transfer roll 120a, and the toner image is transferred onto a sheet. The sheet on which the toner image has been transferred is sent to the fixing device 130 where it is pressurized and heated to fix the toner image on the sheet.

  Here, the image forming apparatus 10 shown in FIG. 1 has the following three modes for transporting the sheet through the fixing device 130. That is, a first transport mode in which a sheet with an image formed on one side is discharged with the image side facing up, and a sheet with the image formed on one side is reversed and discharged with the image side facing down. There are three modes: a conveyance mode and a third conveyance mode in which a sheet on which an image is formed on one side is reversed and sent to the developing device 120 again to form an image on the other side. The first transport mode is a mode used when outputting one or a plurality of sheets on which a single image is formed, and the second transport mode is a series of sheets on which images of a plurality of pages are formed. The third transport mode is a mode used for forming images on both sides of the sheet. In the image forming apparatus 10, one of the three transport modes is designated by the user, and the paper is transported in the designated transport mode.

  In the first transport mode, the sheet is conveyed along the arrow D1 after fixing, and is discharged to the sheet discharge unit 170 by the discharge roll 160 through the sheet correction device 150. In the second transport mode, the sheet is transported along the arrow D2 and then switched back and transported along the arrow D3. As a result, the paper is discharged with the back surface on which no image is formed facing upward. In the third transport mode, the sheet is transported along the arrow D2, and further transported along the arrow D4, then switched back and transported to the developing device 120 along the arrow D5. By being carried along such a path, the sheet is fed into the developing device 120 with the back surface on which no image is formed facing upward. Then, after the toner image is transferred by the developing device 120 and fixed by the fixing device 130, an image is formed on the back surface of the paper. Then, the paper is carried along the arrow D1, and the paper correction device 150 is moved. It is discharged after.

  Here, when the sheet passes through the fixing device 130, the sheet warps in a direction in which the image side becomes concave due to heat mainly applied by the fixing device 130. In addition, when images are formed on both sides of the paper, the surface on the side having the higher image density of the front and back surfaces warps in a concave direction.

  The sheet correction device 150 cools the sheet while correcting the warp deformation of the sheet. Hereinafter, details of the sheet correction apparatus 150 will be described.

  FIG. 2 is a side view showing the sheet correction apparatus shown in FIG.

  The sheet correction apparatus 150 includes two correction mechanisms 151 that correct the warp deformation of the sheet while cooling the sheet.

  As shown in FIG. 2, the two correction mechanisms 151 are arranged so as to be mirror targets. Here, the correction mechanism 151 disposed on the upper side in the drawing bends the paper upward, and the correction mechanism 151 disposed on the lower side in the drawing bends the paper downward. Each correction mechanism 151 includes first and second blowers 151a and 151b that play a role of cooling the sheet. Here, these 1st and 2nd air blowers 151a and 151b are equivalent to each example of the 1st and 2nd air blow parts referred to in the present invention, respectively.

  In addition, the sheet correction apparatus 150 includes a guide unit 152. The guide unit 152 guides the conveyed paper to either the upper or lower correction mechanism 151 in the drawing as will be described later. The guide 152 corresponds to an example of the guide according to the present invention.

  First, correction of paper in the paper correction device 150 will be described in detail.

  FIG. 3 is a diagram illustrating a state in which the deformation of the sheet is corrected by the sheet correction unit in FIG.

  In FIG. 3, the first and second blowers 151a and 151b shown in FIG. 2 are not shown so that it is easy to see how the deformation of the paper is corrected.

  The conveyed paper is guided to one of the two correction mechanisms 151 by the guide unit 152 rotating as indicated by the arrow D6. The warp deformation in the paper can be corrected by bending the paper in the opposite direction to the warp deformation.

  Here, the guide unit 152 guides the sheet according to the sheet conveyance mode. That is, in the first transport mode, the sheet is conveyed with the concave side up, and the guide unit 152 guides the sheet P1 to the upper correction mechanism 151 that bends the sheet upward. In the second transport mode, the sheet is carried with the concave side down, so that the guide unit 152 moves the sheet P2 to the lower correction mechanism 151 that bends the sheet downward. invite. In the case of the third transport mode, the sheet is transported with the surface on which the image is formed for the second time facing up. Also, the paper on which images are formed on both sides warps so that the surface with high image density is concave. Therefore, in this case, the density of the first image is compared with the density of the second image based on the image data representing the image formed on each side of the paper, and the density of the second image is determined. When the density of the first image is higher, the guide unit 152 guides the sheet to the upper correction mechanism 151. When the density of the first image is higher than the density of the second image, the guide unit 152 guides the sheet. The unit 152 guides the sheet to the lower correction mechanism 151.

  The straightening mechanism 151 is pressed against the two stretching rolls 151c and the circulation belt 151d that circulates and moves in the direction of the arrow D8 as the tension rolls 151c rotate in the direction of the arrow D7. A hollow push tube 151e that rotates in the direction of the arrow D9 following the circulation movement of the circulation belt 151d, a bearing 151f that supports the hollow push tube 151e and is movable in the direction of the arrow D10, and this bearing 151f is provided with a cam 151h that contacts the circumference and rotates in the direction of arrow D11 about the eccentric shaft 151g. Here, the circulation belt 151d and the push cylinder 151e correspond to examples of the circulation belt and the push cylinder according to the present invention, respectively.

  Hereinafter, the operation of the correction mechanism 151 will be described by taking as an example a case where a sheet is guided to the upper correction mechanism 151 by the guide unit 152.

  The sheet guided to the correction mechanism 151 (in this example, the sheet P1 conveyed with the concave side up) is circulated by the cam 151h rotating and pushing up the push cylinder 151e via the bearing 151f. A nip is formed between the belt 151d and the push cylinder 151e, and the belt 151d is bent together with the circulation belt 151d. At this time, the push cylinder 151e rotates following the circulation movement of the circulation belt 151d while pressing the paper P1 against the circulation belt. As a result, the sheet P1 is pushed in the direction of the arrow D12 while being bent upward. Thereby, the warp deformation of the paper P1 is corrected.

  Here, in this embodiment, the amount of rotation of the cam 151h is determined according to the type of paper to be corrected and the density of the image formed on the paper. The type of paper is related to how easily the paper is deformed, and the density of the image is related to how much deformation force is applied to the paper. In other words, in the present embodiment, the amount of deformation of the paper, that is, the amount of rotation of the cam 151h required to correct the predicted amount of deformation is determined based on these pieces of information. When the image is formed on one side of the paper, the density of the image is used to determine the rotation amount of the cam 151h. When the image is formed on both sides of the paper, The difference from the density of the back image is used to determine the rotation amount of the cam 151h.

  On the other hand, when the sheet P2 conveyed with the concave side down is guided by the guide unit 152 to the lower correction mechanism 151, the lower correction mechanism 151 performs the same operation and the sheet P2 Correct warping deformation. However, when the sheet is guided to the lower correction mechanism 151, the cam 151h rotates in the opposite direction to push down the push cylinder included in the lower correction mechanism 151 toward the circulation belt. It becomes.

  In the present embodiment, when the warp deformation of the paper is corrected as described above, the paper is simultaneously cooled by the first and second blowers 151a and 151b shown in FIG.

  Next, cooling by the first and second blowers 151a and 151b will be described.

  FIG. 4 is a side view and a top view showing the correction mechanism shown in FIG. 2 and FIG.

  Part (a) of FIG. 4 shows a side view of the correction mechanism 151, and part (b) of FIG. 4 shows a top view of the correction mechanism 151. Here, in the side view, the first blower 151a shown in FIG. 2 is omitted, and in the top view, the second blower 151b shown in FIG. 2 is omitted.

  As shown in part (b) of FIG. 4, the correction mechanism 151 according to the present embodiment includes three rows of circulation belts 151 d and stretching rolls 151 c in the depth direction. And, as shown in part (a) of FIG. 4, one second blower 151b is disposed above the circulation belt 151c in each row. Each circulation belt 151c has a plurality of holes 151d_1, and the cooling air sent out by the second blower 151b passes through the holes 151d_1 of the circulation belt 151c as shown in part (a) of FIG. And it sprays on the nip part of the circulation belt 151c and the pushing cylinder 151e. Thereby, the sheet passing through the nip portion is cooled from the circulation belt 151c side.

  Moreover, both ends of the push tube 151e provided in the correction mechanism 151 of the present embodiment are open, and as shown in part (b) of FIG. 4, the first blower 151a is attached to one end of the opening. . The cooling air sent out by the first blower 151a passes through the inside of the push tube 151e and escapes to the outside through the other opening. The sheet passing through the nip portion is cooled from the side of the pressing cylinder 151e by the cooling air passing through the inside of the pressing cylinder 151e.

  FIG. 5 is a diagram illustrating a state in which the sheet is cooled while the warp deformation is corrected.

  FIG. 5 shows a state where the sheet P1 is nipped by the pusher cylinder 151e pushed up via the bearing 151f by the rotation of the cam 151h and the circulation belt 151d. As a result, the sheet P1 bends in the opposite direction to the warp deformation, and the warp deformation is corrected. Here, as described above, the cooling air is sent into the push tube 151e by the first blower 151a. Thereby, the paper P1 passing through the nip portion is cooled from the push cylinder 151e side. Further, as described above, cooling air is blown from above the circulation belt 151d by the second blower 151b, and the cooling air from the second blower 151b is, of course, around the circulation belt 151b. The paper P1 passes through the plurality of holes 151b_1 and is sprayed on the paper P1 passing through the nip portion. As a result, the paper P1 is also cooled from the circulation belt 151b side.

  As described above, in the correction mechanism 151 of the present embodiment, the sheet P1 is not only corrected for warp deformation but also the heat remaining in the toner image is removed. As a result, it is possible to prevent the toner from contracting after the deformation is corrected once and the sheet from warping again.

  Further, in the correction mechanism 151 of the present embodiment, the amount of air blown by each of the blowers 151a and 151b is the same as the amount of rotation of the cam 151h, and the type of paper to be corrected and the density of the image formed on the paper. It is decided accordingly. That is, when the image density is high, the amount of heat accumulated in the toner image is expected to be large. Therefore, the cooling effect is increased by increasing the amount of air flow. When the image density is low, the heat accumulated in the toner image is increased. Since the amount of air is expected to be small, the amount of blown air can be reduced to save power consumption.

  Further, in the correction mechanism 151 of the present embodiment, when the first blower 151a for cooling is attached to the side of the opening of the push tube 151e and the two correction mechanisms 151 are arranged on the mirror surface, The first blowers 151a of each other do not collide with each other. As a result, the two correction mechanisms 151 can be arranged with a small interval therebetween, and the installation space in the image forming apparatus 10 can be suppressed.

  As described above, the image forming apparatus 10 that is the first embodiment of the image forming apparatus of the present invention has the cooling function and can reduce the installation space, and the sheet correcting apparatus according to the present invention can reduce the installation space. The sheet correction apparatus 150 according to the embodiment is mounted, and the warp deformation of the sheet generated in the image forming apparatus 10 can be corrected so as to prevent re-deformation after correction.

  Next, a second embodiment of the present invention will be described.

  Here, the second embodiment of the image forming apparatus of the present invention is the same as that of the first embodiment described above except that the mounted sheet correction apparatus is the second embodiment of the sheet correction apparatus of the present invention. The basic structure of the second embodiment of the paper straightening device of the present invention is the same as that of the first embodiment of the paper straightening device of the present invention, and the components corresponding to the above-described push cylinder 151e are the same. It is only different. Therefore, in the following description, this difference will be noted and described, and the common points of the second embodiment of the sheet correction apparatus with the first embodiment and the second embodiment of the image forming apparatus of the present invention will be redundantly described. Is omitted.

  FIG. 6 is a top view showing a correction mechanism provided in the sheet correction apparatus according to the second embodiment of the present invention. 6 has much in common with part (b) of FIG. 4, and in FIG. 6, components equivalent to those shown in part (b) of FIG. 4 are shown in part (b) of FIG. The same reference numerals are attached.

  In the correction mechanism 210 shown in FIG. 6, a push tube 211 that presses a sheet against the circulation belt 151d is different from that in the first embodiment. A plurality of holes 211a are opened on the peripheral surface of the push tube 211, and the cooling air sent into the inside by the first blower 151a can be removed to the outside through the holes 211a. As a result, the sheet passing through the nip portion between the push tube 211 and the circulation belt 151d is directly exposed to the cooling air from the push tube 211 side, and the cooling effect is improved.

  The second embodiment of the paper straightening device of the present invention provided with the straightening mechanism 210 described above can also reduce the installation space in the same manner as the first embodiment of the paper straightening device of the present invention, and is further effective. Thus, the sheet can be cooled.

  In the above, as the first and second embodiments of the sheet correction device of the present invention, the sheet correction device including two correction mechanisms is illustrated, but the present invention is not limited to this, and the present invention is not limited thereto. For example, the sheet correction apparatus may be one including one correction mechanism as a sheet correction apparatus.

  Further, in the above, as the first and second embodiments of the sheet correction apparatus of the present invention, the sheet correction apparatus in which two correction mechanisms are arranged on the mirror surface is illustrated, but the present invention is not limited to this. Instead, the sheet correction apparatus of the present invention may be, for example, one composed of two correction mechanisms arranged at arbitrary positions.

  In the above description, as the first and second embodiments of the sheet correction apparatus of the present invention, the sheet correction apparatus including the second blower for cooling the sheet from the circulation belt side is illustrated. Is not limited to this. The sheet correction apparatus according to the present invention includes, for example, a cylinder that is opposed to the second cylinder and sandwiches the push cylinder and the circulation belt, and the cooling air to be fed to the push cylinder is divided and sent into the cylinder. Thus, it may be one that cools the sheet from the circulation belt side through the tube, or one that has only the first blower that sends cooling air into the inside of the push tube.

  Moreover, in the above, as an example of each of the first and second air blowing units referred to in the present invention, the air flow rate is determined according to the type of paper to be corrected and the density of the image formed on the paper. Although the second blower is exemplified, the present invention is not limited to this. The first and second air blowers of the present invention may measure the amount of deformation of the paper directly with, for example, a sensor and the air flow rate may be determined according to the measurement result, or the The air volume may be fixedly determined, for example, to the maximum air flow.

  Moreover, in the above, the 1st air blower which is arrange | positioned beside the opening of the push cylinder which presses a sheet | seat against a circulation belt, and sends a cooling wind directly into the inside of a push cylinder as an example of the 1st ventilation part said to this invention was illustrated. However, the present invention is not limited to this. The 1st ventilation part of this invention may be arrange | positioned in the position away from the push cylinder, for example, and may send a cooling wind into the inside of a push cylinder via a predetermined | prescribed ventilation pipe | tube etc., for example.

  Moreover, in the above, although the 1st air blower which sends cooling air into the inside from one of the opening of the both ends of a push cylinder was illustrated as an example of the 1st ventilation part said to this invention, this invention is limited to this. It is not a thing. The 1st ventilation part of this invention may open the hole in the edge of the surrounding surface of a push cylinder, for example, and may send a cooling wind into the inside of a push cylinder from the hole.

  Moreover, in the above, although the push cylinder which rotates following the movement of a circulation belt was illustrated as an example of the push cylinder referred to in the present invention, the present invention is not limited to this. The push cylinder of the present invention may be, for example, one that is rotationally driven by a driving motor or the like, or may be one that simply presses the paper toward the circulation belt without rotating. . In the case of the latter form, the paper is transported by sliding on the peripheral surface of the pushing cylinder that is stationary without rotating.

1 is a diagram illustrating a first embodiment of an image forming apparatus according to the present invention on which a first embodiment of a sheet correction apparatus according to the present invention is mounted. FIG. It is a side view which shows the paper correction apparatus shown in FIG. It is a figure which shows a mode that the deformation | transformation of a paper is corrected in the paper correction part of FIG. It is the side view and top view which show the correction mechanism shown in FIG. 2 and FIG. It is a figure which shows a mode that a paper is cooled, correcting curvature deformation. It is a top view which shows the correction mechanism with which the paper correction apparatus of 2nd Embodiment of this invention is provided. It is a figure which shows an example of a paper correction apparatus. It is a figure which shows an example of the paper correction apparatus with an air blower.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 110 Paper supply apparatus 111 Pickup roll 112 Feed roll 113 Retard roll 120 Developing apparatus 120a Intermediate transfer roll 130 Fixing apparatus 150 Paper correction apparatus 151 Correction mechanism 151a First blower 151b Second blower 151c Stretch roll 151d Circulation Belt 151d_1 Hole 151e Push cylinder 151f Bearing 151g Eccentric shaft 151h Cam 152 Guide part 160 Discharge roll 170 Paper discharge part 180 Conveying roll 210 Correction mechanism 211 Push cylinder 211a Hole

Claims (5)

In a paper straightening device that corrects warp deformation of paper,
A circulation belt that moves along a predetermined circulation path and runs along with the paper in a part of the circulation path;
A push cylinder that has a hollow round cylindrical shape, and presses the paper running along with the circulation belt against the circulation belt to bend the circulation belt and the paper together on the cylindrical peripheral surface;
A paper straightening device comprising: a first air blowing unit that sends cooling air into the inside of the push tube from an end of the push tube.   2. The sheet correction apparatus according to claim 1, wherein the push tube has a plurality of holes opened in a peripheral surface through which cooling air sent into the inside by the first air blowing section is removed. The circulation belt has a plurality of holes,
The sheet correction apparatus according to claim 1, further comprising a second air blowing unit that blows cooling air toward the circulation belt from a side opposite to the push tube. A plurality of sets comprising the circulation belt, the push tube, and the first air blowing unit are provided in a mirror-surface arrangement such that the sheets running along with the circulation belt of each set are parallel to each other,
The sheet correction apparatus according to claim 1, further comprising a guide unit that guides the sheet to a set corresponding to a direction of warp deformation of the sheet among the plurality of sets. A toner image forming unit that forms a toner image on a sheet based on image data representing an image;
A fixing unit that fixes the toner image on the paper by pressurizing and heating the paper on which the toner image is formed by the toner image forming unit;
A circulation belt that travels along a predetermined circulation path and runs along with the paper that has passed through the fixing unit in a part of the circulation path;
A hollow cylinder having a round cylindrical shape, and a cylinder that presses the paper running along with the circulation belt against the circulation belt to bend the circulation belt and the paper together on the circumferential surface of the cylinder; and
An image forming apparatus comprising: a first air blowing unit that sends cooling air into an inside of the push tube from an end of the push tube.

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