JP2006232516A - Sheet material carrying device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material carrying device and an image forming apparatus, capable of highly accurately detecting positional dislocation of a sheet material with a simple constitution. <P>SOLUTION: This device has a resist part 5 for sending out the sheet material in response to the image forming timing by temporarily stopping the carried sheet material, a voltage impressing means 23 for impressing voltage on the resist part 5, and an electric current detecting means 25 for detecting an output electric current when impressing the voltage. The resist part 5 has an upper roller 20 and a lower roller 30. The upper roller 20 or the lower roller 30 has two divided parts 21 and 22. The voltage is impressed on the respective divided parts 21 and 22 by the voltage impressing means 23, and the positional dislocation of the sheet material is detected from an electric current value outputted from the respective divided parts 21 and 22 detected by the electric current detecting means 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet material conveying apparatus and an image forming apparatus.

  Patent Document 1 includes a registration roller that temporarily stops a conveyed sheet material and sends the sheet material in accordance with the timing of image formation, and a detection sensor that detects the position of the end of the sheet material in the conveyance direction. A technique is disclosed in which a sensor is moved in the axial direction of a roller to detect a positional deviation of an end portion in the conveyance direction of a sheet material.

JP 2003-128337 A

  However, since the conventional technique described in Patent Document 1 described above detects the sheet material by moving the detection sensor in the axial direction of the roller, it is necessary to provide drive means for driving the detection sensor, and the configuration is complicated. There is a problem of becoming. Further, since the position of the end portion of the sheet material is read from a position away from the sheet material, there is a problem that it is difficult to detect the end portion position of the sheet material with high accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet material conveying apparatus and an image forming apparatus that have a simple configuration and can detect a positional deviation of a sheet material with high accuracy.

  In order to solve the above-mentioned problem, the invention described in claim 1 suspends a conveyed sheet material and applies a voltage to the resist portion, and a resist portion that sends out the sheet material in accordance with the timing of image formation. A voltage application unit and a current detection unit for detecting an output current when a voltage is applied, the registration unit includes an upper roller and a lower roller, and the upper roller or the lower roller includes two divided portions, A voltage is applied to each divided portion by the applying means, and a positional deviation of the sheet material is detected from a current value output from each divided portion detected by the current detecting means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the registration unit is a width direction driving unit that drives the upper roller or the lower roller in the width direction, and a drive control unit that controls the width direction driving unit. The drive control means moves the roller in the width direction in accordance with the difference in output current value from each divided portion detected by the current detection means.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the registration unit includes a conveyance direction driving unit that drives the upper roller or the lower roller in the conveyance direction of the sheet material, and a conveyance direction driving unit. A drive control means for controlling the sheet material, and when correcting the positional deviation of the sheet material, the conveyance speed of the sheet material by the conveying direction driving means is adjusted until the correction of the positional deviation of the sheet material is completed. It is characterized in that the speed is lower than when the deviation is not corrected.

  According to a fourth aspect of the present invention, there is provided the current value storing means for storing the output current value of each divided portion detected by the current detecting means in the invention according to any one of the first to third aspects. When the sheet material is continuously conveyed, only the first sheet material that is continuously conveyed is detected by the current detection means, and the output current value is stored in the current value storage means. The positional deviation correction of the sheet material conveyed after the first is performed based on the output current value stored in the current value storage means.

  The invention described in claim 5 includes the sheet material conveying device according to any one of claims 1 to 4.

  According to a sixth aspect of the invention, in the fifth aspect of the invention, a plurality of paper feeding units that store sheet materials of different sizes, and a replenishment detecting unit that detects the replenishment of the sheet material to the paper feeding unit. The detection of the positional deviation of the sheet material is performed only for the sheet material transported first after the replenishment detecting means detects the replenishment of the sheet material to the paper feeding unit, and the current value storage means The output current value is stored, and the positional deviation correction of the sheet material conveyed after the second is performed based on the output current value stored in the current value storage means.

  According to a seventh aspect of the present invention, in the fifth aspect of the present invention, the image forming apparatus includes an operation unit that sets a sheet size of the sheet material, and detection of a positional deviation of the sheet material is performed by the operation unit. After changing the paper size of the sheet material, only the sheet material conveyed first is stored and the output current value is stored in the current value storage means, and the positional deviation of the sheet material conveyed second and later is corrected. Is performed based on the output current value stored in the current value storage means.

  According to an eighth aspect of the present invention, in the invention according to the fifth aspect, the image forming apparatus has a double-sided printing mode for printing both sides of the sheet material. The sheet material stored in the current value storage means is used only when the sheet material is conveyed and the output current value is stored in the current value storage means, and correction of the positional deviation of the sheet material when the back surface of the sheet material is conveyed. This is performed based on the output current value on the surface of the substrate.

  The invention described in claim 9 includes, in the invention described in claim 7, a correction mode that corrects the positional deviation of the sheet material and a non-correction mode that does not correct the positional deviation of the sheet material. The non-correction mode can be selected on the operation unit.

  According to the present invention, a voltage is applied to each of divided portions (one roller and the other roller) of at least one of the upper roller and the lower roller, and the positional deviation of the sheet material is determined from the difference in the output current value. Since the detection is performed, for example, a driving means for driving the detection sensor as in the prior art is not required, and the configuration is simple. In addition, since the sheet material can be detected from the difference between the output current values by applying a voltage to each roller, it can be detected with high accuracy unlikely to be affected by the mounting accuracy like a detection sensor.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front view showing a resist portion of the image forming apparatus of the present invention, FIG. 2 is a perspective view showing the resist portion of the image forming apparatus of the present invention, and FIG. 3 is a control block diagram of the image forming apparatus according to the present invention. 4 is an overall schematic view showing an image forming apparatus of the present invention.

  As shown in FIG. 3, the color image forming apparatus 1 according to the present embodiment includes a paper feeding unit (paper feeding cassettes 3 and 4) provided at the lower part of the apparatus main body, and an image forming unit provided at the upper part thereof. 10 and a paper discharge section (paper discharge tray 8) provided on the upper surface of the apparatus. In the figure, a broken line indicates a sheet (sheet material) conveyance path. The image formed by the image forming unit 10 is transferred to the sheet fed from the sheet feeding units 3 and 4, and the transferred image is fixed by the fixing unit 7. Then, the paper is discharged to the paper discharge tray 8. In addition, a registration unit 5 is provided in the conveyance path to temporarily stop the sheet fed and conveyed from the sheet feeding units 3 and 4 and send the sheet to the image forming unit 10 at the timing of image formation. .

  The image forming unit 10 is provided with a transfer unit 6 that is disposed so as to be inclined so that the paper feed side is on the bottom and the discharge side is on the top. Four image forming units 1M, 1C, and 1Y of magenta (M), cyan (C), yellow (Y), and black (B) in order from the lower side along the upper traveling side of the transfer conveyance belt of the transfer unit 6. 1K are arranged side by side. Each of the image forming units 1M, 1C, 1Y, and 1K includes photosensitive drums 11M, 11C, 11Y, and 11K as image carriers and a developing unit. Further, the image forming apparatus 1 includes an optical writing unit 2 that irradiates the surface of each of the photosensitive drums 11M, 11C, 11Y, and 11K while scanning the laser beam based on the image data.

  The registration unit 5 includes an upper roller 20 that drives and conveys a sheet in the conveyance direction, and a lower roller 30 that contacts and rotates the upper roller 20. The upper roller 20 is divided in a direction perpendicular to the conveying direction (one roller 21 and the other roller 22), a voltage applying device (voltage applying means) 23 for applying a voltage to each of the rollers 21 and 22, and a voltage A current detection device (current detection means) 25 for detecting an output current output when the roller is applied, a worm portion 28 provided at the end of the roller shaft of the upper roller 20, and the conveyance direction of the upper roller 20 And a transport drive motor (transport direction drive means) 26 for driving the motor. Voltage application terminals 23a and 23b and current detection terminals 25a and 25b are provided at ends of the lead wires connected to the voltage application device 23 and the current detection device 25, respectively. One voltage application terminal 23 a and one current detection terminal 25 a are in contact with the end of one roller 21, and the other voltage application terminal 23 b and the other current detection terminal 25 b are connected to the other roller 22. Touching the edge. The voltage application terminals 23a and 23b and the current detection terminals 25a and 25b are attached to the bracket 27, respectively.

  The lower roller 30 is provided with a width direction driving means 40 for driving the roller in the width direction. The width direction driving means 40 is fixed to a rotator 33 that is rotated by driving of the reciprocating drive motor 32 of the lower roller 30, an arm portion 35 attached to the rotator 33, and one end of the lower roller 30. The reciprocating drive motor 32 drives the rotator 33 so that the movement assisting member 31 attached to the arm portion 35 moves, and the lower roller 30 moves in the axial direction. It has become. Further, the rotational movement amount of the rotator 33 is controlled by the control unit 60, and the movement amount of the lower roller 30 is changed according to the difference in the output current value detected by the current detection device 25. Yes.

  Next, operations and effects of the image forming apparatus according to the present embodiment will be described. When a copy start button is pressed on the operation panel (operation unit) 90 of the image forming apparatus 1, a sheet having a specified size is fed from the sheet feeding cassettes 3 and 4 one by one. The fed paper is transported in the direction of the image forming unit 10 by the transport roller, and abuts against the registration unit 5 provided in the transport path and stops.

  When the sheet hits the registration unit 5 and stops, a voltage is applied from the voltage application device 23 to one roller 21 and the other roller 22 of the upper roller 20. On the other hand, the current detection device 25 outputs current from one roller 21 and the other roller 22. The current values output from one roller 21 and the other roller 22 are sent to the control unit 60. The controller 60 compares the current value output from one roller 21 with the current value output from the other roller 22. Data indicating the relationship between the difference between the output current values and the positional deviation of the paper is input into the control unit 60, and the positional deviation amount of the paper is calculated based on the data. When the paper misregistration amount is calculated, the calculated value is sent to a driver that drives and controls the rotator 35 of the width direction driving unit 40, and corresponds to the paper misregistration amount calculated by the control unit 60. The rotator 35 rotates by a predetermined angle, and the lower roller 30 moves in the axial direction by a predetermined amount. When the lower roller 30 moves in the axial direction, the paper also moves in conjunction with the movement of the lower roller 30, and the positional deviation of the paper is corrected. When the correction of the positional deviation of the paper is completed, the upper roller 20 is driven to rotate, and the paper is sent into the image forming unit 10.

  According to the present invention, a voltage can be applied to one roller 21 and the other roller 22 that are the upper rollers 20 of the registration unit 5 to detect the deviation of the sheet from the difference in the output current value. A driving means for driving the detection sensor as in the technology is not required separately, and the configuration is simple. In addition, since a voltage can be applied to each of the rollers and the deviation of the sheet can be detected from the difference in the output current value, it can be detected with higher accuracy than the detection sensor.

  Next, other embodiments will be described. In the following description, parts having the same functions and effects as those of the first embodiment described above are denoted by the same reference numerals, and detailed description of the parts is given. In the following description, differences from the first embodiment will be mainly described.

  In the second embodiment, when correcting the paper misalignment, the paper transport speed is lower than when the normal misalignment is not corrected until the correction of the paper misalignment is completed. Like to do. That is, when correcting the misalignment of the sheet, the lower roller 30 is moved in the horizontal direction by the reciprocating drive motor 32. During this time, the conveyance drive motor 26 is driven to convey the sheet toward the image forming unit 10. ing.

  As described above, since the paper is being transported toward the image forming unit 10 before the correction of the paper misregistration is completed, it is necessary to keep waiting in the registration unit 5 for the time for correcting the misalignment of the paper. Therefore, it is possible to shorten the time from the end of the correction of the sheet misalignment to the start of image formation, and to prevent a decrease in image formation speed.

  Next, a third embodiment will be described. In the third embodiment, a current value storage unit (current value storage means) 70 that stores the output current value detected by the current detection device 25 is provided. When the paper is continuously conveyed, the detection of the positional deviation of the paper by the current detection device 25 is performed only for the first paper that is continuously conveyed, and the output current value is stored in the current value storage unit 70. . When the second and subsequent sheets are conveyed to the registration unit 5, registration correction is performed based on the output current value stored in the current value storage unit 70.

  As described above, when the sheets are continuously conveyed, with respect to the second and subsequent sheets, the detection result of the positional deviation performed on the first sheet (the output current stored in the current value storage unit 70). Since the registration correction is performed based on the (value), it is not necessary to detect misregistration every time the sheet is conveyed, and a reduction in image formation productivity can be prevented.

  Next, a fourth embodiment will be described. In the fourth embodiment, when the paper replenishment detection sensor 80 provided in the paper feed unit (paper feed cassettes 3 and 4) detects that a new paper is set in the paper feed units 3 and 4, the detection is performed. The positional deviation detection is performed on the first sheet conveyed at the start of the first job after being performed, and the output current value is stored in the current value storage unit 70. For the second and subsequent sheets of paper, the positional deviation of the paper is corrected based on the output current value stored in the current value storage unit 70.

  When a new sheet is set in the sheet feeding units 3 and 4, the positional deviation detection is performed only for the first sheet conveyed at the start of the first job after the detection, and the second sheet For subsequent sheets, the registration correction is performed based on the output current value stored in the current value storage unit 70, so that it is not necessary to detect misregistration for each conveyed sheet, and the productivity of image formation is improved. Decline can be prevented.

  Next, a fifth embodiment will be described. In the fifth embodiment, when the sheet size to be fed is changed on the operation panel (operation unit) 90, the first sheet conveyed at the start of the first job after the change is changed. The position shift is detected, and the output current value is stored in the current value storage unit 70. For the second and subsequent sheets of paper, the positional deviation of the paper is corrected based on the output current value stored in the current value storage unit 70.

  When the paper size is changed, the positional deviation detection is performed only for the first sheet conveyed after the size is changed. Therefore, it is necessary to detect the positional deviation for each second and subsequent sheets conveyed. Therefore, a decrease in image formation productivity can be prevented.

  Next, a sixth embodiment will be described. In the sixth embodiment, when double-sided printing is performed, misregistration detection is performed only on one side of the first transported paper, and the output current value is stored in the current value storage unit 70. When the opposite surface of the sheet is conveyed or for the second and subsequent sheets, the output current value stored in the current value storage unit 70 is fed back to correct the misalignment of the sheet. Done.

  In this way, when duplex printing is performed, sheet misregistration detection is performed only on one side of the first conveyed sheet. Therefore, the position misalignment is performed on the back side of the sheet or for each sheet conveyed after the second. It is not necessary to perform detection, and a reduction in image formation productivity can be prevented.

  Next, a seventh embodiment will be described. In the seventh embodiment, on the user setting mode screen on the operation panel 90, the presence / absence of a correction mode for correcting the positional deviation of the paper can be selected. In this way, since the presence / absence of the correction mode can be selected, the difference between the image quality and the productivity in each mode is compared and considered (for example, when the image quality is regarded as important, the correction mode is selected and the productivity is regarded as important). Can be set to the preferred mode.)

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. In the above-described embodiment, the upper roller 20 includes two divided portions, but the lower roller 30 may include two divided portions.

It is a front view showing a resist part of the image forming apparatus of the present invention. It is a perspective view showing a resist part of the image forming apparatus of the present invention. FIG. 3 is a control block diagram of the image forming apparatus according to the present invention. 1 is an overall schematic diagram illustrating an image forming apparatus of the present invention.

Explanation of symbols

1 Image forming device 3, 4 Paper feed unit (paper feed unit)
5 Registration part 20 Upper roller 21 One roller (divided part)
22 The other roller (divided part)
23 Voltage application device (voltage application means)
25 Current detection device (current detection means)
30 Lower Roller 40 Width Direction Driving Unit 60 Control Unit 70 Current Value Storage Unit 80 Paper Supply Detection Sensor (Paper Supply Detection Unit)
90 Operation panel (operation unit)

Claims (9)

  A resist unit that temporarily stops the conveyed sheet material and sends the sheet material in accordance with the timing of image formation, a voltage applying unit that applies a voltage to the resist unit, and a current detection that detects an output current when the voltage is applied The registration unit has an upper roller and a lower roller, and the upper roller or the lower roller has two divided parts, and a voltage is applied to each divided part by the voltage applying means, and the current detecting means A sheet material conveying apparatus that detects a positional deviation of a sheet material from a current value output from each detected divided portion.   The registration unit includes a width direction driving unit that drives the upper roller or the lower roller in the width direction, and a drive control unit that controls the width direction driving unit. The drive control unit is configured to detect each divided portion detected by the current detection unit. The sheet material conveying apparatus according to claim 1, wherein the roller is moved in the width direction in accordance with a difference between the output current values.   The registration unit includes a conveyance direction drive unit that drives the upper roller or the lower roller in the conveyance direction of the sheet material, and a drive control unit that controls the conveyance direction drive unit. 3. The sheet conveying speed by the conveying direction driving means is set to be lower than when the sheet material positional deviation is not corrected until correction of the positional deviation of the material is completed. The sheet material conveying apparatus as described.   Current value storage means for storing the output current value of each divided portion detected by the current detection means is provided, and when the sheet material is continuously conveyed, the detection of the positional deviation of the sheet material by the current detection means is continuously conveyed. The current value storage means stores only the first sheet material and the output current value is stored in the current value storage means. The correction of the positional deviation of the sheet material conveyed after the second is corrected to the output current value stored in the current value storage means. The sheet material conveying apparatus according to claim 1, wherein the sheet material conveying apparatus is performed based on the sheet material.   An image forming apparatus comprising the sheet material conveying device according to claim 1.   A plurality of sheet feeding units that store sheet materials of different sizes, and a replenishment detection unit that detects the replenishment of the sheet material to the sheet feeding unit. After detecting the replenishment to the paper section, only the sheet material conveyed first is stored and the output current value is stored in the current value storage means. 6. The image forming apparatus according to claim 5, wherein the deviation correction is performed based on the output current value stored in the current value storage means.   The image forming apparatus includes an operation unit for setting the sheet size of the sheet material, and the detection of the sheet material misalignment is performed only on the first sheet material conveyed after the operation unit changes the sheet size of the sheet material. And the output current value is stored in the current value storage means, and the positional deviation correction of the sheet material conveyed after the second is performed based on the output current value stored in the current value storage means. The image forming apparatus according to claim 5.   The image forming apparatus has a double-sided printing mode for printing both sides of a sheet material. Detection of positional deviation of the sheet material is performed only when one side of the sheet material is conveyed, and the output current value is stored in the current value storage means. 6. The positional deviation correction of the sheet material when the back surface of the sheet material is conveyed is performed based on the output current value on the surface of the sheet material stored in the current value storage means. Image forming apparatus. 8. A correction mode for correcting misalignment of the sheet material and a non-correction mode that does not correct misalignment of the sheet material, wherein the correction mode and the non-correction mode can be selected by an operation unit. The image forming apparatus described in 1.

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