JP2008050145A - Paper post-treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper post-treating device capable of accurately detecting the paper discharged from an image forming device and properly correcting the curl. <P>SOLUTION: This paper post-treating device conveys the paper S discharged from the image forming device through a predetermined path and applies a post-treating to the paper S. The paper post-treating device comprises distance measuring sensors 42a, 42b, 42c for detecting the curled amount of the paper S and paper passage guide plates 23, 24 installed near the sensors. The paper passage guide plates 23, 24 are disposed oppositely to the front and rear surfaces of the paper S, respectively. The center portions 23a, 24a thereof are formed in flat surface shapes. Both portions 23b, 24b thereof orthogonal to the conveying direction A are so diverged that the both side portions 23b, 24b are separated from each other and the downstream side portions 23c, 24c in the conveying direction A are separated from each other. The sensors 42a, 42b, 42c detect the curled amount of the paper S at the portion where the paper passage guide plates 23, 24 are diverged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet post-processing apparatus, and more particularly to a sheet post-processing apparatus that performs post-processing such as sorting and stapling on a sheet on which an image is formed.

  In general, an image forming apparatus such as an electrophotographic copying machine or a printer is often connected to a sheet post-processing apparatus that performs post-processing such as sorting or stapling on a sheet on which an image is formed. By the way, in an image forming apparatus using electrophotography, a transferred toner image is fixed on a sheet by heat and pressure, and the sheet that is fixed and discharged from the image forming apparatus main body may be largely curled. The size and direction of curl varies depending on the paper type and production lot, and is not constant.

  When a large curled sheet is carried into the post-processing apparatus, problems such as a shift occur when the sheets are stacked and aligned, and a discharge failure occurs when the sheets are discharged onto the tray.

  Therefore, Patent Document 1 describes that a curl amount of a sheet is detected by an optical sensor, a curl correction roller is deformed according to the detection result, and a curl amount is changed by changing a winding amount around the roller. . Patent Document 2 describes that a curl amount of a sheet is detected by a distance measurement sensor, and the curling is corrected by changing the rotation direction of the large roller according to the detection result (curl direction).

When curl is detected, the paper is required to be as free as possible. However, in both Patent Documents 1 and 2, the paper is not in a necessary free state at the time of curl detection, but is in a state of being restricted by the paper passing guide member, and a large curl is restricted by the guide member and detected. It was impossible. Further, since any of the curl correcting means uses a roller member, only curl in a plane parallel to and perpendicular to the conveying direction can be corrected.
JP 2002-326754 A Japanese Patent Laid-Open No. 11-124269

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a paper post-processing device that can detect the curl amount of paper discharged from an image forming apparatus as accurately as possible.

  Another object of the present invention is to provide a paper post-processing apparatus that can achieve the above-mentioned object and can appropriately correct the curl of the paper.

In order to achieve the above object, the present invention provides:
In a paper post-processing apparatus that transports paper discharged from the image forming apparatus through a predetermined path and performs post-processing on the paper.
A paper alignment section for stacking and aligning paper,
A curl amount detecting means for detecting a curl amount of the paper disposed on the upstream side of the paper aligning unit;
A paper passing guide member installed in the vicinity of the curl amount detecting means,
The sheet passing guide member is disposed to face the front side and the back side of the sheet to be transported, each of which has a planar shape in the center, and both side portions orthogonal to the transport direction spread in directions away from each other, And the upstream part of the transport direction spreads away from each other,
The curl amount detecting means detects a curl amount of the paper at a portion where the sheet passing guide member is widened;
It is characterized by.

  In the sheet post-processing apparatus according to the present invention, the pair of sheet passing guide members are spread in the direction in which both the side portions and the upstream portion are separated from each other with respect to the sheet conveying direction. The curled part is conveyed in a free state, and the curl amount is detected in this state. That is, since the sheet passing guide member does not regulate the curled portion of the sheet, the curl amount can be detected as accurately as possible in any direction.

  In the sheet post-processing apparatus according to the present invention, it is preferable that the planar shape portion of the sheet passing guide member has a width dimension smaller than a minimum sheet width dimension that can be conveyed. It is possible to detect the curl of the minimum size paper as accurately as possible in a free state.

  The curl amount detecting means preferably includes a plurality of distance measuring sensors for measuring the distance from the front surface side or the back surface side of the paper to the paper at regular time intervals in a direction orthogonal to the transport direction. By measuring the distance to the paper at regular intervals, the exact curl shape of the paper can be detected during conveyance.

  Further, the paper post-processing apparatus according to the present invention is provided with a curl correcting means for correcting the curl of the paper according to the detection result of the curl amount detecting means. Accordingly, it is possible to appropriately correct the paper in which the curl in any direction is detected, and it is possible to prevent the paper from being poorly aligned and discharged.

  It is preferable that the curl correcting unit includes a humidifying member for humidifying the sheet, and the humidifying member is controlled in a humidifying position and / or a humidifying amount according to a detection result of the curl amount detecting unit. Furthermore, a humidity detecting means for detecting the environmental humidity or an input means for the detected environmental humidity is provided, and the humidifying position and / or the humidifying amount of the humidifying member is controlled according to the detection result of the curl amount detecting means and the environmental humidity. Is preferred. By optimally humidifying the paper, the paper curl can be corrected without adversely affecting the post-processing operation.

  Embodiments of a sheet post-processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

  1 and 2 schematically show the overall configuration of a sheet post-processing apparatus according to the present invention. The paper post-processing apparatus 1 includes transport rollers 11, 12, 13, and 14, paper passing guide plates 21 to 26, a humidifying unit 30, a paper alignment tray 35, and a post-processing mechanism (not shown). . The post-processing mechanism is a well-known mechanism such as a staple unit that drives staples on the sheets S aligned on the alignment tray 35, or a punch unit that opens punch holes in a sheet in the middle of conveyance. The rollers 11 to 14 and the paper passing guide plates 21, 22, 25, and 26 are not shown in FIG. 1 for the sake of simplicity.

  A measurement unit 41 that measures environmental humidity is provided inside the sheet post-processing apparatus 1 or inside the image forming apparatus 100. Further, a detecting means 42 for detecting the curl amount of the paper S discharged from the image forming apparatus 100 is provided on the entrance side of the paper passing guide plates 23 and 24. The curl amount detection means 42 will be described in detail later.

  The paper S discharged from the electrophotographic image forming apparatus 100 such as a copying machine or a printer may be partially or wholly curled due to heating or pressurization by the toner fixing unit. Trouble occurs in processing. Therefore, in this embodiment, the curling amount of the paper S is detected by the detection unit 42 with respect to the paper S immediately before the transport roller 12, and the detected curl amount and the environmental humidity measured by the humidity measuring unit 41 are used. Thus, the humidifying unit 30 is controlled so that the curl of the sheet S is appropriately corrected immediately before the alignment tray 35. Therefore, detection signals and measurement signals from the curl amount detection means 42 and the humidity measuring unit 41 are input to the CPU 50, and the CPU 50 calculates the humidification position and the humidification amount for the paper S and controls the humidification unit 30.

  As shown in FIG. 3, the curl amount detection unit 42 includes distance measurement sensors 42 a, 42 b, 42 c that measure the distance from the back side of the paper S to the paper S in a direction orthogonal to the transport direction A. . The sensors 42a, 42b, and 42c measure the distance to the back surface of the paper S at regular time intervals according to the conveyance of the paper S, and detect the curl amount.

  In order to convey the paper S as much as possible when the curl amount is detected, the pair of upper and lower sheet passing guide plates 23 and 24 have both center portions 23a and 24a having a planar shape and both side portions orthogonal to the conveyance direction A. 23b and 24b are inclined and spread in a direction away from each other (vertical direction), and upstream portions 23c and 24c in the transport direction A are also inclined and spread in a direction away from each other (vertical direction). The conveying roller 12 is disposed in the central portions 23a and 24a that form the planar shape of the sheet passing guide plates 23 and 24.

  In the present embodiment, since the sheet passing guide plates 23 and 24 are spread in the vertical direction, even if both side portions in the transport direction A of the paper S or upstream and downstream portions in the transport direction A are greatly curled, The curl amount can be accurately detected without the paper passing guide plates 23 and 24 interfering with the curl.

More specifically, in order to be able to detect the curl of the smallest size paper S that can be transported, if the maximum curl height that can be detected on the minimum size paper S is a and the maximum curl width is b, a planar shape is formed. The width L of the central portions 23a and 24a is set to L ≦ (minimum sheet width−2b). Further, the inclination angle θ of the upper and lower paper passing guide plates 23 and 24 is set to θ ≧ tan ^{−1 (a / b)} in order to correspond to the maximum curl. By setting the sheet passing guide plates 23 and 24 as described above, the curled portion of the sheet S is sent to the sheet passing guide plates 23 and 24 in a free state regardless of the direction in which the sheet S is curled. This makes it possible to accurately detect the curl amount.

  The curl state of the paper S differs depending on the type of the paper S, the production lot, and the like. For example, as shown in FIG. 4A, the curl is curled upward or downward on both sides in the transport direction A, or FIG. As shown in FIG. 4, it curls upward or downward at the upstream portion or downstream portion in the conveyance direction A, or curls upward or downward at the corner portion (on the diagonal line) as shown in FIG. .

  The distance measurement sensors 42a, 42b, and 42c are arranged in a direction orthogonal to the transport direction A, and measure the distance to the paper S at regular time intervals when the paper S passes over the sensors 42a, 42b, and 42c. The curl amount is detected based on the detection signal. The distance measurement sensors 42a, 42b, and 42c are orthogonal to the transport direction A in accordance with the width of the paper S, for example, as shown in FIG. Move in the direction you want. That is, FIG. 5A shows the set position when the narrow paper S passes, and as shown in FIG. 5B, when the wide paper S passes, it is moved in the direction of arrow B. To measure the distance to the sheet S.

  As a second example, six sensors 42a to 42f are arranged as shown in FIGS. 6A and 6B, and the sensors 42a to 42f to be used are selected according to the width of the sheet S to be conveyed. Also good.

  On the other hand, the curl amount detection timing is the distance measurement sensors 42a, 42b, and 42c from the sensor 43 from the time when the leading edge of the paper S is detected by the sensor 43 (see FIG. 2) provided in the discharge unit of the image forming apparatus 100. The curl detection is started from the time when the time calculated by the distance up to and the paper conveyance speed has elapsed, and is detected until the trailing edge of the paper S passes through the sensors 42a, 42b, and 42c at regular intervals.

  Since the distance data measured by the sensors 42a, 42b, and 42c varies depending on the curl state of the paper S, by analyzing the distance data of the three sensors 42a, 42b, and 42c, the shape and curl of the curl are analyzed. The amount can be detected.

  As shown in FIG. 7, when the paper S is curled on both sides in the transport direction A, the measured distance data obtained by the sensors 42a, 42b, and 42c are shown in FIGS. 8A, 8B, and 8C, respectively. ), The measurement distance differs for each of the sensors 42a, 42b, and 42c, but the change due to the measurement time is small. As shown in FIG. 9, when the sheet S is curled in the upstream portion or the downstream portion in the transport direction A, the measurement distance data obtained by the sensors 42a, 42b, and 42c is shown in FIGS. As shown in B) and (C), the measurement distance is small for each of the sensors 42a, 42b, and 42c, and changes greatly depending on the measurement time. Also, as shown in FIG. 11, when the paper S is curled at the corners, the measured distance data by the sensors 42a, 42b, and 42c are shown in FIGS. 12A, 12B, and 12C, respectively. As shown, the measurement distance varies greatly for each of the sensors 42a, 42b, and 42c, and the change due to the measurement time is also large.

  In response to detection of the above curl amounts by the sensors 42a, 42b, and 42c, the humidification unit 30 performs humidification for correcting the curl on the paper S. As shown in FIGS. 13 and 14, the humidifying unit 30 has matrix-like nozzles 31 formed in the transport direction A and orthogonal directions toward the paper S, and moisture is supplied from the respective nozzles 31 toward the paper S. Correct the curl by blowing out.

  Although not shown, the humidifying unit 30 is provided with a mechanism for selecting an operating nozzle 31 and a mechanism for determining an operation timing, and releases moisture from the nozzle 31 at a timing necessary for curl correction. FIG. 13 shows a correction state when the sheet S is curled on both sides in the transport direction A. FIG. 14 shows a correction state when the sheet S is curled in the upstream portion or the downstream portion in the transport direction A.

  The operation control of the humidifying unit 30 is calculated by the CPU 50 based on the curl detection results by the sensors 42a, 42b, and 42c. In the calculation of the operation control of the humidifying unit 30 by the CPU 50, the environmental humidity data measured by the humidity measuring unit 41 is also taken into consideration, and the amount of moisture ejected from the nozzle is also adjusted. For example, the moisture content is increased when the humidity is low, and the moisture content is decreased when the humidity is high. Such control of the amount of water makes the curl correction more precise.

  By the curl correction process, it is possible to eliminate adverse effects such as the alignment of the paper S on the alignment tray 35 being disturbed or the punch position being shifted by the punch hole forming process.

(Other examples)
The sheet post-processing apparatus according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist.

  For example, the configuration of the sheet passing path, the detailed structure and shape of the sheet passing guide plate and the humidifying unit are arbitrary. Further, the number of installed distance measuring sensors, the arrangement position, etc. are also arbitrary. In the above embodiment, the curl amount of the paper is detected on the upstream side in the transport direction of the paper guide plate. However, the downstream portion in the transport direction of the paper guide plate is expanded in the vertical direction. The curl amount may be detected.

1 is a perspective view showing a schematic configuration of a sheet post-processing apparatus according to the present invention. FIG. 4 is a cross-sectional view showing a paper conveyance path of the paper post-processing apparatus. (A) is a perspective view which shows the principal part of the said paper post-processing apparatus, (B) is XX sectional drawing of (A). It is a perspective view which shows the various curl shapes in a paper. It is explanatory drawing which shows the 1st example of a distance measurement sensor. It is explanatory drawing which shows the 2nd example of a distance measurement sensor. It is a perspective view which shows the distance measurement state by the 1st shape of a curl and a sensor. It is a graph which shows the measurement data of the 1st shape shown in FIG. It is a perspective view which shows the distance measurement state by the 2nd shape of a curl and a sensor. It is a graph which shows the measurement data of the 2nd shape shown in FIG. It is a perspective view which shows the distance measurement state by the 3rd shape of a curl and a sensor. It is a graph which shows the measurement data of the 3rd shape shown in FIG. It is a perspective view which shows the 1st example of the curl correction state by a humidification unit. It is a perspective view which shows the 2nd example of the curl correction state by a humidification unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Paper post-processing apparatus 23, 24 ... Paper passing guide board 30 ... Humidification unit 35 ... Matching tray 42a-42f ... Distance measuring sensor 100 ... Image forming apparatus A ... Conveying direction S ... Paper

Claims (7)

In a paper post-processing apparatus that transports paper discharged from the image forming apparatus through a predetermined path and performs post-processing on the paper.
A paper alignment section for stacking and aligning paper,
A curl amount detecting means for detecting a curl amount of the paper disposed on the upstream side of the paper aligning unit;
A paper passing guide member installed in the vicinity of the curl amount detecting means,
The sheet passing guide member is disposed to face the front side and the back side of the sheet to be transported, each of which has a planar shape in the center, and both side portions orthogonal to the transport direction spread in directions away from each other, And the upstream part of the transport direction spreads away from each other,
The curl amount detecting means detects a curl amount of the paper at a portion where the sheet passing guide member is widened;
A paper post-processing apparatus characterized by the above.   The sheet post-processing apparatus according to claim 1, wherein the planar shape portion of the sheet passing guide member has a width dimension smaller than a minimum sheet width dimension that can be conveyed.   The curl amount detecting means is configured by arranging a plurality of distance measuring sensors for measuring the distance from the front side or the back side of the paper to the paper at regular time intervals in a direction perpendicular to the transport direction. The sheet post-processing apparatus according to claim 1 or 2.   The sheet post-processing apparatus according to claim 3, wherein the distance measuring sensor is movable in a direction orthogonal to the transport direction according to a sheet size.   5. The sheet post-processing apparatus according to claim 1, further comprising a curl correcting unit that corrects a curl of the sheet according to a detection result of the curl amount detecting unit.   6. The curl correcting unit includes a humidifying member for humidifying a sheet, and the humidifying member is controlled in a humidifying position and / or a humidifying amount according to a detection result of the curl amount detecting unit. Paper post-processing equipment.   Furthermore, a humidity detection means for detecting environmental humidity or an input means for the detected environmental humidity is provided, and the humidification position and / or the humidification amount of the humidification member is controlled according to the detection result of the curl amount detection means and the environmental humidity. The sheet post-processing apparatus according to claim 6.

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