JP2007153556A - Sheet material skew correcting device and sheet material processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a skew of a sheet material and image failure caused by the skew of the sheet material, by properly correcting the skew, even when slipping is caused much between a paper feeding roller and the sheet material. <P>SOLUTION: When the slipping is much between the paper feeding roller 7 and the sheet material S, driving of a paper sending roller is started after driving the paper feeding roller 7 by changing the synchronous driving timing of the paper sending roller 4 and the paper feeding roller 7. That is, the skew is corrected by sufficiently forming a loop of the sheet material S by rotatingly driving the paper feeding roller 7 apparently more than ordinary driving δ with respect to the paper sending roller 4 of a stopped state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet material skew correction device provided in a sheet material processing apparatus that performs a predetermined process on sheet materials fed one by one.

  The sheet material processing apparatus referred to here includes, for example, an image forming apparatus (printer, copying machine, facsimile, etc.) that forms an image on a recording material (sheet material) fed one by one. There is a document image reading device that reads an image of a document (sheet material) fed sheet by sheet.

2. Description of the Related Art Conventionally, in a sheet material skew feeding correction device equipped in an image forming apparatus such as an ink jet method, a sheet feeding roller and a pinch roller on the downstream side in the conveying direction of a sheet material fed and conveyed from an automatic separation and feeding unit The sheet material is fed by the paper feed roller for a certain period of time after the leading edge of the sheet material comes into contact with the nipping portion of the paper feed roller and the pinch roller, and the sheet material is bent (making a loop). Some have corrected the skew of the sheet material. (For example, see Patent Document 1.)
For example, as shown in FIG. 5, the pulse motor 101 is rotationally driven, and the paper feed roller 102 connected to the pulse motor 101 is rotationally driven in the clockwise direction of FIG. At this time, the urging means 104 on the paper feed stacker 103 presses the sheet material S on the paper feed stacker 103 against the paper feed roller 102. As a result, a frictional force is generated between the outer peripheral surface of the paper feed roller 102 and the sheet material S, and the sheet material S on the paper feed stacker 103 is conveyed in the rotational direction of the paper feed roller 102 by the frictional force. The conveyed sheet material S is separated into one uppermost sheet by a separating means (not shown), and the separated sheet material S is further conveyed.

  The sheet material S is transported by the rotation of the sheet feed roller 102 and passes through the sheet material detection means 106 (consisting of a photo interrupter 106-1 and a detection lever 106-2). At this time, the pinch roller 109 provided at a position facing the sheet feeding roller 108 on the upstream side of the print head (image forming unit) 107 across the sheet material conveyance path is held in a rotation stopped state. The sheet material S is further conveyed and abuts against a nipping portion (nip portion) N between the paper feeding roller 108 and the pinch roller 109. Here, the leading edge of the sheet material S is received by the nipping portion N between the paper feeding roller 108 and the pinch roller 109 in a rotation stopped state. Thereafter, the paper feed roller 102 continues to be rotated by a predetermined amount (a fixed time). As a result, a predetermined deflection (loop) is formed on the leading edge side of the sheet material S, and the deflection reaction force causes the leading edge of the sheet material S to be parallel to the sandwiching portion N between the paper feeding roller 108 and the pinch roller 109. Is corrected.

  Thereafter, the sheet feeding roller 102 and the sheet feeding roller 108 start to rotate in synchronization, convey the sheet material S to a predetermined printing start position, and the sheet material S is completely fed.

  Here, in order to appropriately correct the skew of the sheet material S, an appropriate amount of loops must be formed. For this reason, the loop amount is managed here using the sheet material detection means 106. This method will be described with reference to FIG.

Since the distance X between the sheet material detecting means 106, the paper feeding roller 108, and the pinching roller 109 is determined in advance, the sheet feeding roller 102 is moved after the leading edge of the sheet material S has passed the detecting means 106. The sheet material S can be fed by being rotated by an amount corresponding to the distance X, and the leading end of the sheet material S can be brought into contact with the nipping portion N between the paper feeding roller 108 and the pinch roller 109. From this state, a predetermined amount of loops can be formed on the sheet material S by further rotating the sheet feeding roller 102 by an amount δ corresponding to the loop amount. According to this, since the detection means normally used in the image forming apparatus can be used, the loop amount can be controlled easily and inexpensively.
JP-A-4-53973

  However, since the loop amount of the sheet material S is always set to a constant amount in the conventional example, there are the following drawbacks.

  A paper feed roller for feeding and transporting the sheet material S stacked on the paper feed stacker in a transport mechanism of an image forming apparatus such as a printer simplifies the mechanism such as a drive gear train and drive switching timing, and costs For the purpose of providing a sheet feeding mechanism in which the operator can easily load the sheet material S into the sheet feeding stacker, the cross section of the sheet feeding roller 102 shown in FIG. A D-shaped shape consisting of an arc-shaped portion for conveyance and a chord portion for separating (FIG. 6) from the stacked sheet material S (a shape obtained by cutting a part of a circular shape into a flat shape) ). The paper feed roller 102 is generally used in a small ink jet printer or the like. The arc length of the arc portion of the sheet feeding roller 102 is determined for each apparatus. Usually, the distance Y from the leading end of the stacked sheet material S to the detecting means 106 on the downstream side in the conveying direction, and the detecting means 106 to the roller pair. The distance X is set to be equal to the distance obtained by adding the distance X to the sandwiching portion N of 108 and 109, the loop amount δ created in the sheet material S to correct skew, and a certain distance margin α.

  Further, a material having a high friction coefficient such as EPDM rubber, non-solex rubber, foamed urethane rubber, or the like is provided on the outer peripheral surface (paper contact surface) of the paper feed roller 102, and the paper feed roller 102 is driven to rotate. Thus, a frictional force is generated between the outer peripheral surface of the sheet feeding roller and the sheet material S urged to the sheet feeding roller 102 by the urging means 104, and the sheet material S is rotated in the rotation direction of the sheet feeding roller 102 by the frictional force. To be sent to.

  At this time, the usage environment such as the temperature and humidity outside the apparatus, the state of the rubber surface on the outer periphery of the paper feed roller (attachment of paper dust, rubber scraps, etc.) and the type of sheet material S to be fed (sheet) The sheet is fed by the frictional force between the sheet feeding roller 102 and the sheet feeding roller 102 that are driven to rotate due to the influence of the friction coefficient of the material surface, the conveyance resistance due to the waist of the sheet material S, and the surface condition of the sheet material S. Sliding may occur between the sheet material S.

  For this reason, since the loop amount of the sheet material S is always set to a constant amount in the conventional method, if a large slip occurs between the D-shaped sheet feeding roller 102 and the sheet material S, the sheet material S is not provided. A fixed amount loop was formed, and proper skew correction could not be performed, causing problems such as image defects due to skew.

  The present invention has been proposed in view of such problems, and even when a large slip occurs suddenly between the D-shaped paper feeding roller and the sheet material, an appropriate amount of loop is formed in the sheet material. An object of the present invention is to provide a sheet material skew correction device capable of effectively correcting material skew and effectively preventing sheet material skew and image defects caused by sheet material skew. To do.

  In order to achieve the above object, the present invention provides a sheet feed roller that feeds a sheet material in contact with the stacked sheet material, a pulse motor that drives the sheet feed roller, and the sheet feed roller. Nipping and conveying means for nipping and conveying the fed sheet material; and sheet material detecting means for detecting the leading edge of the sheet material fed between the paper feed roller and the nipping and conveying means. The sheet material fed by the sheet feeding roller is conveyed by a predetermined amount by the nipping and conveying unit, and then the driving of the sheet feeding roller and the nipping and conveying unit is temporarily stopped, and then the nipping and conveying unit is moved in the sheet material conveying direction. The present invention relates to a sheet material skew correction device that is driven in the opposite direction to send the leading end of the sheet material to the upstream side of the nipping and conveying means to form a predetermined amount of loop in the sheet material.

  In order to achieve the above object, the present invention provides a pulse number counting unit that counts the number of pulses of the pulse motor, and the paper feed roller after forming a loop based on information from the sheet material detecting unit, The simultaneous drive timing of the nipping and conveying means is controlled.

  Here, the nipping and conveying means is a roller pair.

  Also, the sheet material skew correction device of the present invention is a sheet material processing device that performs a predetermined process (for example, forms an image on the sheet material) on the sheet material fed one by one. This is used as means for correcting the skew of the fed sheet material.

  According to the present invention, even when there is a lot of slippage between the sheet feeding roller and the sheet material, the driving of the sheet feeding roller and the sheet feeding roller is controlled to adjust the loop amount to be formed on the sheet material, so that Thus, it is possible to effectively prevent image defects caused by sheet material skew or sheet material skew.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show the configuration of a sheet material skew correction device 100A according to the first embodiment of the present invention. 1 is a perspective view, and FIG. 2 is a side view.

  The image forming means 1 uses an ink jet system, and a carriage 2 is pivotally supported by a guide means 3 and is driven by a motor (not shown) in the direction perpendicular to the paper surface (FIG. 2), that is, the width direction of the sheet material S (main scanning direction). An ink jet recording head 1 that discharges ink in accordance with an image signal is mounted on the carriage 2. Accordingly, the carriage 2 is moved in the main scanning direction, and ink is ejected from the recording head 1 to perform image recording on the sheet material S.

  The paper feed roller 4 is a roller for carrying the sheet material S, and is rotatably supported by a chassis (not shown) on the upstream side in the carrying direction of the recording head 1. The surface of the roller 4 is provided with rubber that increases the friction coefficient. In recent years, in order to improve the conveyance accuracy of the sheet material S, Al, SUS, SUM materials have been ground and the surface has a coefficient of friction to increase the friction coefficient of the sheet material or urethane applied resin. Some have particles such as alumina and ceramic attached. The paper feed roller 4 is connected to a pulse motor (not shown) and is driven to rotate. A plurality of rotatable pinch rollers 5 are provided in the sheet width direction at positions facing the sheet feeding roller 4 across the sheet material conveyance path. The pinch roller 5 is pressed against the paper feeding roller 4 by pressing means (not shown).

  On the upstream side in the transport direction of the paper feed roller 4, a paper feed roller 7 that is rotatably supported by a chassis (not shown) and is connected to a pulse motor 6 to be driven to rotate is provided. The sheet feeding roller 7 is a roller for picking up the sheet material S and conveying the sheet material S to the sheet feeding roller 4, and a rubber for increasing the friction coefficient is provided on the surface. In addition, the paper feed roller 7 can simplify the mechanism such as the drive gear train and the drive switching timing to reduce the cost, and provide a paper feed mechanism that allows the operator to easily load the sheet material S into the paper feed stacker 8. The cross section has a D-shaped shape including an arc-shaped portion for feeding and conveying the sheet material and a string portion for separating from the stacked sheet material S.

  The paper feed stacker 8 has a function of stacking automatically fed sheet materials S. On the paper feed stacker 8, an urging means 9 for urging the sheet material S to the opposing paper feed rollers 7 is provided. .

  A sheet material detection unit 10 is provided on the upstream side in the transport direction of the paper feed roller 4 and on the downstream side in the transport direction of the paper feed roller 7. This sheet material detection means 10 comprises a photo interrupter 10-1 and a detection lever 10-2. The sheet material detection means 10 is a means for detecting the end of the conveyed sheet material.

  FIG. 4 shows the configuration of the control system of the sheet material skew correction device 100A.

  This control system is mainly composed of a control means (CPU) 13 for controlling the driving of the pulse motor 6. The control means 13 is supplied with a count signal from the pulse number counting means 14 for counting the number of pulses of the pulse motor 6 and a detection signal from the sheet material detecting means 10 for detecting the sheet material S. The control means 13 controls the drive of the pulse motor 6 based on these information.

  Next, the sheet feeding / conveyance and skew correction of the sheet material S will be described in detail with reference to FIGS.

(Feeding and transporting)
When the apparatus is in a standby state, as shown in FIG. 2, the urging means 9 on the paper feed stacker 8 is in a state of being retracted from the paper feed roller 7, and the paper feed roller 7 has a D-shaped string portion. It is in a state of being horizontally oriented toward the biasing means 9 side.

  When the apparatus receives a paper feed command, the pulse motor 6 is rotationally driven, and the paper feed roller 7 connected to the pulse motor 6 is rotationally driven in the clockwise direction of FIG. At this time, the biasing means 9 on the paper feed stacker 8 presses the sheet material S on the paper feed stacker 8 against the paper feed roller 7. Thus, a frictional force is generated between the arcuate outer peripheral surface of the sheet feeding roller 7 that is rotationally driven and the sheet material S, and the sheet material S on the sheet feeding stacker 8 is rotated in the rotational direction of the sheet feeding roller 7 by the frictional force. It is conveyed to. The conveyed sheet material S is separated into one uppermost sheet material by a separating means (not shown), and the separated sheet material S is further conveyed.

(Skew correction)
When the sheet material S is conveyed by the distance Y by the rotation of the sheet feeding roller 7, the leading edge of the sheet material S passes through the sheet material detection means 10. Further, the sheet material S is conveyed by a predetermined amount by the roller pairs 4 and 5, and the conveyance of the sheet material S is stopped by temporarily stopping the driving of the paper feed roller 7 and the roller pairs 4 and 5. At this time, the number of driving pulses of the pulse motor 6 from when the sheet feeding roller 7 is driven to rotation until the sheet material S passes through the sheet material detecting means 10 is counted by the pulse number counting means 14, and the count signal is sent to the control means 13. Sent. Thereafter, the roller pairs 4 and 5 holding the sheet material S are driven in a direction opposite to the sheet material conveying direction, and the leading end of the sheet material S is conveyed by a predetermined amount upstream from the holding portion of the roller pairs 4 and 5. To do. At this time, the paper feed roller 7 is not driven, and a loop is formed in the sheet material S.

  Further, the paper feeding roller 4 and the paper feeding roller 7 start to rotate synchronously, and the sheet material S is sandwiched between the paper feeding roller 4 and the pinch roller 5 and sent to a predetermined printing start position. The carriage 2 is moved in the main scanning direction for each row, and ink is ejected from the recording head 1 to record an image on the sheet material S.

  Here, when the signal (number of pulses of the pulse motor 6) sent to the control means 13 is in the range of α shown in FIG. 3, the frictional force between the sheet feeding roller 7 and the sheet feeding roller 7 that are driven to rotate is used. It is determined that there is little slip between the sheet material S being fed. The sheet material S is conveyed by a distance X + δ by a paper feed roller 7 and roller pairs 4 and 5. Further, when the sheet feeding roller 4 and the pinch roller 5 are reversed, the sheet material S is returned by the distance δ, and a predetermined amount of deflection (loop) is formed at the leading end of the sheet material S. Then, the leading edge of the sheet material S is parallel to the nipping portion N between the paper feeding roller 4 and the pinch roller 5 and the skew correction of the sheet material S is performed. As described above, when the slip between the sheet feeding roller 7 and the sheet material S is small, a loop of a predetermined amount δ is formed in the sheet material S and skew correction is performed.

  Further, when the signal (number of pulses of the pulse motor 6) sent to the control means 13 exceeds the range of α shown in FIG. 3, there is a lot of slip that occurs between the paper feed roller 7 and the sheet material S. to decide. The sheet material S is conveyed by a distance X + δ by a paper feed roller 7 and roller pairs 4 and 5. Further, when the sheet feeding roller 4 and the pinch roller 5 are reversed, the sheet material S is returned by the distance δ, and a predetermined amount of deflection (loop) is formed at the leading end of the sheet material S. However, in actuality, the loop amount does not reach δ, which is insufficient, and there are many slips that occur between the paper feed roller 7 and the sheet material S, so that proper skew correction may not be performed. If there is a lot of slippage between the sheet feeding roller 7 and the sheet material S, the synchronization timing of the sheet feeding roller 4 and the sheet feeding roller 7 is changed to drive the sheet feeding roller 4 after driving the sheet feeding roller 7. Start. That is, by apparently rotating the paper feed roller 7 with respect to the stopped paper feed roller 4 more than the normal δ, a loop of the sheet material S is sufficiently formed and skew correction is performed.

  Thereafter, the sheet material S is sandwiched between the paper feeding roller 4 and the pinch roller 5 and fed to a predetermined printing start position, and the carriage 2 is moved in the main scanning direction for each line of the paper feeding roller 4 and the recording head 1 is also moved. Then, ink is discharged from the sheet material and image recording is performed on the sheet material S.

  As described above, in the present embodiment, even when there is a lot of slippage between the sheet feeding roller 7 and the sheet material S, the pulse of the pulse motor 6 when the leading edge of the sheet material passes through the sheet material detection means 10. In this case, skew correction is performed by adjusting the amount of loop formed in the sheet material S, and the deterioration of image quality due to the skew of the sheet material S is effectively prevented. Can do.

1 is a perspective view showing a configuration of a sheet material skew correction device according to an embodiment of the present invention. The side view which shows the structure of the sheet material skew feeding correction | amendment apparatus by embodiment of this invention. The side view explaining the method of control of the sheet material skew feeding correction device by an embodiment of the invention. The block circuit diagram which shows the structure of the control system of the sheet | seat material skew correction apparatus by embodiment of this invention. The side view which shows the structure of the sheet material skew feeding correction apparatus of a prior art example. The side view explaining the control method of the sheet material skew feeding correction apparatus of a prior art example.

Explanation of symbols

1. Inkjet recording head (image forming means)
4 Paper feeding roller (Nipping and conveying means)
5 Pinch roller (Nipping and conveying means)
6 Pulse motor 7 Paper feed roller 10 Sheet material detection means S Sheet material

Claims (4)

A sheet feed roller that feeds the sheet material in contact with the stacked sheet material, a pulse motor that drives the sheet feed roller, and the sheet material fed by the sheet feed roller is nipped and conveyed And a sheet material detecting means for detecting a leading end of the sheet material fed between the sheet feeding roller and the nipping and conveying means, and the sheet fed by the sheet feeding roller After the material is conveyed by a predetermined amount by the nipping and conveying means, the driving of the paper feed roller and the nipping and conveying means is temporarily stopped, and then the nipping and conveying means is driven in a direction opposite to the sheet material conveying direction to In the sheet material skew correction device for feeding the leading end of the material to the upstream side of the holding and conveying means to form a loop in the sheet material,
Based on the information from the pulse number counting means for counting the number of pulses of the pulse motor and the sheet material detecting means, the simultaneous drive timing of the paper feed roller and the nipping and conveying means is controlled after forming a loop. Sheet material skew feeding correction device.   2. The sheet material skew correction device according to claim 1, wherein the nipping and conveying means is a pair of rollers.   In a sheet material processing apparatus that performs a predetermined process on a sheet material fed one by one, a sheet material skew correction device is provided as means for correcting the skew of the sheet material fed one by one. 2. The sheet material processing apparatus according to claim 1, wherein:   4. The sheet material processing apparatus according to claim 3, further comprising image forming means for forming an image on the sheet material as means for performing the predetermined processing.

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