JPH0532367A - Device for correcting curl of paper sheet - Google Patents

Abstract

PURPOSE:To guide a paper sheet to a curl correcting device without being engaged with a guide gate member even if the paper sheet ejected from a fixing device generates lateral curls in an image forming device using an electronic photographic system. CONSTITUTION:In an image forming device, a curl correcting device 1 is disposed between a fixing device 5 and postprocessing device and has two curl correcting members 2, 3 and a guide means for distributing paper sheets with a guide gate member 10 disposed in the upstream section. The guide gate member 10 is constituted to have the front touching surface 11 inclined by a predetermined angle to a surface orthogonal to the transfer direction of the paper sheet so that when the front end of the paper sheet touches the front touching surface of the guide gate member it touches the paper sheet only in one portion and the tip of the paper sheet is guided along the front touching surface to guide the paper sheet along upper and lower guide surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curl correction device disposed between a copy discharge portion of an image forming apparatus such as an electronic copying machine and a post-processing device such as a sorter, and more particularly to a curl correction device. The present invention relates to a device that can correct the curl of a paper depending on the direction of the curl.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system such as an electronic copying machine, a toner image formed on a photosensitive drum is transferred onto a sheet, and the sheet carrying the toner image is fixed through a fixing device. , A means for discharging as a copy is used. Further, a post-processing device such as a sorter is arranged with respect to the image forming apparatus to sort the copies and store them in a tray of the sorter so that the post-processing of the copies can be easily performed. . In the image forming apparatus as described above, as a general fixing device, a heating roller type device is often used. In the fixing device, a heating roller that contacts a toner image bearing surface of a sheet is used. And a pressure roller that presses the back surface of the paper against the heating roller are opposed to each other.

A copy fixed through the heating roller type fixing device generally tends to be curved toward the side corresponding to the heating roller, and is ejected in a state where curl occurs in the sheet conveying direction. Often. However, even with general copy paper, the direction of curl generated in a copy (hereinafter referred to as paper) may differ depending on the water content of the paper, and the direction of curl generated in the paper may differ depending on the quality of the paper. . When the sheets are stored in the sorter or the like, if the sheets are curled, a trouble may occur when the sheets are conveyed, or the number of sheets stored in the tray of the sorter may decrease. The problem occurs.

In order to solve the above-described problem of paper curl, it is considered that a curl correction device as disclosed in, for example, Japanese Utility Model Laid-Open No. 61-28754 is used in combination with an electronic copying machine. There is. In the curl correction device shown in the conventional example, the curl correction device having different curl correction directions is arranged in the paper path for ejecting the paper from the fixing device via the distribution gate member. Then, the curl of the paper is guided to a curl correction device having a correction performance according to the curl direction of the paper, the curl of the paper is curved in the opposite direction, the curl of the paper is eliminated, and the paper is sent toward the post-processing device. I am trying.

However, in the above-described curl correcting device, the gate member cannot be accurately operated unless the curl direction of the paper discharged from the fixing device can be known in advance by some means. There's a problem. Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 63-180668, a means for detecting the direction of the curl is arranged upstream of the curl correcting device, and the curl direction is detected by the curl detecting means. The gate member is swung to guide the paper. Then, in the above-mentioned conventional example, the curl of the paper is curved in the opposite direction, and the curl of the paper can be discharged to the post-processing device in a state where the curl is eliminated.

[0006]

However, as disclosed in Japanese Patent Laid-Open No. 63-180668, a switching gate is arranged upstream of the curl correcting device to detect the curl direction of the paper. In the case where the sheet is provided, since the detection unit and the switching gate are arranged, there arises a problem that the configuration of the sheet discharge unit becomes complicated. Further, since the number of members constituting the curl correction device and the number of operation members are increased, maintenance of those devices becomes troublesome, and in the case of a failure or the like, the operator's burden is increased. Therefore, for example, as disclosed in Japanese Unexamined Patent Publication No. 61-174060, the driving member for the switching gate and the like is omitted, and sorting according to the curl direction of the paper is performed to facilitate the curl correction operation. It is also conceivable to use a method that makes it possible.

The curl correction device disclosed in Japanese Patent Laid-Open No. 61-174060 is constructed as shown in FIG. 7, and the upstream roller device and the upstream roller device are provided at the upstream portion and the downstream portion of the curl correction device 20, respectively. 21 and a downstream roller device 22 are respectively arranged, and a curl correcting portion is provided above and below a portion between the two roller devices 21 and 22 in a state of being covered by the guide plates 23 and 24. In the curl correction unit, an upper guide member 25 and a lower guide member 26 are arranged between the upper and lower guide plates, and the upper guide plate 23 and the upper guide member 25 are provided and two guide members 25, 26 are provided.
And a portion between the lower guide member 26 and the lower guide plate 24 are configured as paper guide paths. The upper guide member 25 and the lower guide member 2
The reference numeral 6 is a substantially triangular member, in which the central portion corresponding to the guide path is formed as a flat surface, and the corner portion is projected to the other side.

Then, the sheet fed from the upstream roller device 21 toward the curl correcting section is made to pass through the upper and lower sheet guide paths according to the direction of the curl, and the uncurled sheet is It is adapted to pass through a guide path between two guide members. Further, in the curl correction device 20, the paper conveyance speed by the downstream roller device 22 is set to be higher than that of the upstream roller device 21, and the paper nipped by both rollers is
The curl is slid in a state of being pressed against the corner portion of the upper guide member 25 or the lower guide member 26, and the action of correcting the curl of the sheet is performed. Therefore, for example, when the paper is curled downward (the front end of the paper is warped upward), the paper is inserted into the upper guide path and squeezed at the corners of the upper guide member 25 to eliminate the curl. To be done.

In the case of using the curl correcting device as shown in the conventional example, when the paper is curled in the length direction, the action of guiding the paper by the upper guide member or the lower guide member is exerted. It can be done relatively accurately.
However, the distribution of water content of the paper, the paper quality,
The paper may curl in the width direction depending on conditions such as the temperature distribution in the fixing device. For example, as shown in FIG. 8, when the paper Pc that has been curled in the width direction is fed into the curl correcting device, it may come into contact with the leading end of the upper guide member or the like at two locations at the same time.
In the example shown in FIG. 8, only one guide gate member 10 is shown, but the explanation is given assuming that it corresponds to one of the two guide members in FIG. 7. When the paper Pc as described above is locked by the two contact portions Pb with respect to the leading end contact surface 11 of the guide member 10, the paper Pc is guided above and below the guide gate member. There is a problem that it is not possible to follow along, and a jam occurs. It is relatively frequent in a general electronic copying machine or the like that the paper is stopped by being locked by the guide gate member as described above.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional curl correcting device, simplifies the structure of the curl correcting device, and reduces the curl in the width direction. However, it is an object of the present invention to provide a device capable of performing the guiding action in the curl correcting device in a good state.

[0011]

SUMMARY OF THE INVENTION According to the present invention, in a downstream portion of a fixing device, a curl correcting device is divided into two upper and lower sheet paths via a guide gate member, and the upper and lower sheet paths have different curl correcting directions. A curl correcting device is configured by arranging the respective means, and the guide gate member is provided with a wedge-shaped distribution surface facing in the moving direction of the sheet, and the distribution surface is
Configured by inclining with respect to the plane perpendicular to the paper transport direction,
A paper guide surface is provided above and below the tip contact surface to form a paper curl correction device. Further, in the present invention, the tip contact surface of the guide gate member is linear,
It may be configured to have a curved shape or a shape to be distributed to both sides, and any portion of the leading end abutting surface may be configured to have an angle within a range of 0 ° <θ <90 ° with respect to a surface perpendicular to the sheet conveying direction. it can. Further, in the curl correcting device of the present invention, the two curl correcting members are arranged in combination with a large-diameter roller composed of an elastic roller and a small-diameter roller composed of a roller member having rigidity. The curl can be corrected by imparting a curving action to the small diameter roller side with respect to the sheet passing through the sheet.

By using the curl correcting device constructed as described above, even if the paper introduced into the curl correcting device is curled in the width direction, the leading end portion of the paper is not covered by the guide gate member. Since only one position contacts the leading end contact surface, the sheet can be moved along the upper and lower guide surfaces of the guide gate member. Therefore, it is possible to prevent the paper from being caught by the guide gate member and causing a jam. Further, since the curl correcting device of the present invention does not require a drive mechanism or the like to be provided in the portion for guiding the paper, the mechanism of the device can be simplified.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet curl correcting device of the present invention will be described with reference to the illustrated example. As shown in FIG. 1, the curl correcting device 1 of the present invention is arranged between an insertion path 17 for guiding the paper from the fixing device 5 and a carry-out path 18 connected to a post-processing device such as a sorter. There is. A conveyance roller device 6 is arranged in the paper introducing portion of the curl correcting device 1, and the paper sent from the fixing device 5 is introduced into the curl correcting device 1. Further, an upper guide plate 7 and a lower guide plate 8 are arranged at upper and lower portions of the curl correction device 1, a guide gate member 10 is arranged between the upper and lower guide plates, and the guide gate member 10 and the upper and lower guide plates are arranged. A paper guide path is formed between the board and the board. Then, the upward curl correcting mechanism 2 and the downward curl correcting mechanism 3 are arranged with respect to the upper and lower guide paths,
The curl correction member eliminates the curl of the paper.

The upward curl correcting mechanism 2 and the downward curl correcting mechanism 3 have large-diameter rollers 2a and 3a, respectively.
The small diameter rollers 2b and 3b are provided so as to face each other, the large diameter roller is configured as an elastic roller, and the small diameter roller is configured as a roller having rigidity. It is provided so as to cut into the roller. The upward curl correcting mechanism acts to curl the sheet curled upward in a direction opposite to the curl direction to eliminate the curl. Then, a curl correcting action opposite to the upward curl correcting mechanism is provided.

In the curl correcting device 1, a guide gate member 10 for guiding a curled sheet.
Are configured as shown in FIG. The guide gate member 10 shown in FIG. 2 is provided with a knife-edge-shaped linear guide surface 11 facing the paper path 17 side, and the linear guide surface 11 is perpendicular to the paper conveyance direction. It is configured to be inclined to the one side by an angle θ with respect to the line.
The inclination angle θ of the linear guide surface is 0 ° <θ <9.
Although it can be arbitrarily set within the range of 0 °, the angle θ can be arbitrarily set according to the paper used in the image forming apparatus. Further, with the straight guide surface 11 as a boundary, an upper guide surface 15 and a lower guide surface 16 are provided above and below the linear guide surface 11.
And are arranged as inclined surfaces so that the paper can be distributed vertically.

Apart from the guide gate member shown in FIG. 2, the curl correcting device of the present invention may use a guide gate member 10a as shown in FIG.
The guide gate member 10a has a tip contact surface as a curved guide surface 12, and the inclination angle θ of any portion of the curved surface of the curved guide surface 12 is 0 ° <θ <9.
It is set in the range of 0 °. The guide surfaces 15 and 16 arranged above and below the curved guide surface 12 are
The guide gate member 10 has the same structure.

Further, as the guide gate member of the present invention,
It is also possible to configure the guide gate member 10b as shown in FIG. In the guide gate member 10b,
A mountain-shaped guide surface 13 whose tip contact surface is mountain-shaped in a plan view is provided, and a protrusion 13 at the center of the mountain-shaped guide surface 13 is provided.
From c, the two slopes 13a, 1
3b is arranged. Further, the angles θ1 and θ2 of the inclined surfaces provided on the guide gate member 13 are set to 90 ° or less as in the embodiments of the two guide gate members, but if the angles of both inclined surfaces are made different. Therefore, it is possible to favorably perform the action of guiding the sheet.

As described above, the tip abutting surface is provided so as to be inclined with respect to the direction perpendicular to the sheet conveying direction, and two guide surfaces are provided downstream of the tip abutting surface as a boundary. When the guide gate member is formed by forming the guide gate member, the tip end portion of the tip contact surface is provided with an arc R having a small diameter as shown in FIG. In the present invention, the circular arc R is set to about 0.5 mm, so that when the leading edge of the sheet abuts, the sheet is brought into contact with the leading edge abutting surface as in the case of a perfect knife edge. It is possible to prevent the cut-in, and it is possible to favorably perform the function of guiding the paper.

Further, as described above, since the leading end abutting surface is inclined, in the guide gate member of the present invention, as shown in FIG. 6, the sheet Pc contacts the leading end of the guide gate member 10. When the sheet abuts on the contact surface 11, the leading end portion of the sheet comes into contact only at one contact point Pa.
Then, since the leading end of the sheet moves sequentially along the leading end contact surface of the guide gate member, the guide gate member is moved in accordance with the curl direction of the sheet with respect to the first contact point Pa. It will move toward the upper and lower guide surfaces.

The operation of guiding the paper when the curl correcting device 1 is constructed by using the guide gate member of the present invention constructed as described above will be described. In the curl correcting device shown in FIG. 1, the paper as the paper discharged from the fixing device 5 is fed by the conveying roller device 6 to the paper path 1.
The inside of 7 is conveyed toward the sorting part by the guide gate member 10. Then, the sheet is guided by the tip contact surface of the guide gate member 10 in accordance with the curling direction of the sheet.
The sheet with the upward curl is guided toward the upward curl correction mechanism 2, and the sheet with the downward curl is guided toward the downward curl correction mechanism 3. In the upward curl correction mechanism or the downward curl correction mechanism, the action of strongly curving the paper in the direction opposite to the curl direction is added, and the action of eliminating the curl generated in each paper is imparted. Therefore, the sheet sent to the post-processing device through the curl correction device 1 is in a state in which the curl is eliminated, and therefore, even when stored in the tray of the sorter, the influence of the curl does not occur. It should be noted that, in the case of a sheet having a curl in the lateral direction, the curl is automatically eliminated even after passing through any correction member. Therefore, in the present invention, only the curl in the length direction is curled. All that is required is to provide a means for solving it.

In the curl correcting device constructed as described above, as the curl correcting member, a large-diameter roller and a small-diameter roller are arranged opposite to each other as shown in the figure, and other Any conventionally known curl correction mechanism can be used. Further, even when two roller members are used as the curl correcting member, the diameter and material of the roller members may be any material and roller diameter depending on the quality of the paper used in the image forming apparatus. Can be used. Further, the curl correcting device of the present invention can be provided not only between the fixing device and the post-processing device, but also in an automatic double-sided copying machine, at any position in the conveying path of the one-side copied sheet. is there.

[0022]

Since the paper curl correcting device of the present invention is constructed as described above, the structure of the paper guide member of the curl correcting member can be simplified and the paper guiding action can be improved. It can be done well. Also,
By using the guide gate member configured as described above, even if the paper introduced into the curl correction device is curled in the width direction, the leading end of the paper is abutted against the leading end of the guide gate member. Since only one position abuts on the surface, the sheet can be moved along the upper and lower guide surfaces of the guide gate member. Therefore, it is possible to prevent the paper from being caught by the guide gate member and causing a jam. Further, since the curl correcting device of the present invention does not require a drive mechanism or the like to be provided in the portion for guiding the paper, the mechanism of the device can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a curl correction device of the present invention.

FIG. 2 is a perspective view of a guide gate member used in the curl correcting device of the present invention.

FIG. 3 is a perspective view of another embodiment of the guide gate member.

FIG. 4 is a perspective view of another embodiment of the guide gate member.

FIG. 5 is a cross-sectional view showing the shape of the tip of the tip contact surface in the guide gate member of the present invention.

FIG. 6 is an explanatory diagram of a guide function for a sheet that is laterally curled by a guide gate member.

FIG. 7 is an explanatory diagram showing a configuration of a conventional curl correction device.

FIG. 8 is an explanatory view of a paper guide action by a conventional guide member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Curl correction device, 2 Upward curl correction mechanism, 3 Downward curl correction mechanism, 5 Fixing device, 10 Guide gate member, 11-13 Tip contact surface, 15 Upper guide surface, 16 Lower guide surface, 20 Conventional curl correction apparatus.

Claims (2)

[Claims] 1. A curl correction device is provided at a downstream portion of a fixing device, which is divided into two upper and lower paper paths through a guide gate member, and curl correction means having different curl correction directions are respectively arranged in the upper and lower paper paths. A device is provided, wherein the guide gate member is provided with a wedge-shaped distribution surface facing in the moving direction of the paper, and the distribution surface is formed by inclining with respect to a surface perpendicular to the paper transport direction, A curl correction device for paper, characterized in that paper guide surfaces are provided above and below the tip contact surface. 2. The leading end contact surface of the guide gate member is formed in a linear shape, a curved shape, or a shape that is distributed to both sides, and any part of the leading end contact surface is a surface perpendicular to the sheet conveying direction. On the other hand, the curl correction device for a sheet according to claim 1, wherein the curl correction device is configured to have an angle in a range of 0 ° <θ <90 °.