JP2019123574A - Image processing apparatus - Google Patents

Abstract

To provide an image processing apparatus capable of conveying a recording medium in a reduced time while positional deviation of the recording medium can be adjusted.SOLUTION: A light emitting element of a line sensor is on during a period from time T0 to time T1. A paper stop roller pair moves a recording material P by CPU rotating a shift motor. A light receiving element of the line sensor accumulates a light receiving amount during the period. During a period from time T1 to time T2, the CPU reads from each light receiving element an accumulated amount of a light receiving amount during the period from time T0 to time T1. During a period from time T2 to time T3, the CPU determines a position of an end portion of the recording material P using the light receiving amount read from each light receiving element, and determines a deviation amount of the position of the end portion from a reference position. The CPU rotates the shift motor in order to eliminate in a period from time T3 to time T4 the deviation of the recording material P.SELECTED DRAWING: Figure 8

Description

  The present disclosure relates to adjustment of misalignment of a recording medium conveyed in an image processing apparatus.

  Conventionally, in order to realize reading of an original with high accuracy and / or formation of an image in an image processing apparatus, from an appropriate position in a direction intersecting the transport direction on a recording medium (original and / or paper) Technology has been proposed to more accurately recognize the For example, Japanese Patent Application Laid-Open No. 2003-219117 (Patent Document 1) discloses an original document both-end detection device that uses a black-and-white opposing plate in the document conveyance path. The apparatus scans all pixels of the document while moving the black portion of the black and white opposing plate to the focal position, and then moves the white portion of the black and white opposing plate to the focal position and scans all pixels of the document . Then, the apparatus calculates the position of the document using data of all pixels obtained at two timings.

JP 2003-219117 A

  However, according to the technology described in Patent Document 1, it is necessary to acquire data of all pixels of the recording medium (original or paper) at each of the two timings as described above. As a result, the time required to transport the recording medium including the adjustment of the position may be long, and the time required to generate data of an original or to form an image on the recording medium may be long.

  The present disclosure has been conceived in view of the above circumstances, and an object thereof is to provide an image processing apparatus capable of conveying a recording medium in a shorter time while adjusting the positional deviation of the recording medium. It is.

  According to one aspect of the present disclosure, a recording medium conveyance path, a sensor disposed to face at least a part of the recording medium on the conveyance path, and a sensor facing the sensor across the recording medium on the conveyance path Image processing apparatus, comprising: an opposing plate disposed on the transport path; and driving means configured to relatively move the recording medium on the transport path and the opposing plate in a first direction intersecting the transport direction in the transport path Is provided. The opposing plate contains a plurality of colored lines. The sensor detects the amount of light reflected from the opposing plate side. The plurality of color lines are arranged to be adjacent in the first direction. The driving means relatively moves the recording medium on the transport path and the opposing plate in the first direction in a predetermined period. The processor further includes a processor configured to determine the position of the end of the recording medium in the first direction on the transport path using the detection output of the sensor corresponding to the predetermined period.

  The sensor is configured to receive light emitted by the light emitting element and a light emitting element configured to emit light toward the recording medium on the conveyance path for a predetermined period, and to be adjacent to each other in the conveyance direction. A plurality of light receiving elements may be included. The processor may be configured to use, as the detection output, an integrated value of the light reception amount of each of the plurality of light receiving elements of the period.

  Each of the plurality of color lines may have a predetermined length in the first direction. The driving means may be configured to move the recording medium on the transport path relative to the counter plate over a predetermined length for a predetermined period.

  Each of the plurality of color lines may have a predetermined length in the first direction. The predetermined length is an integral multiple of the pixel of the light receiving element of the sensor in the first direction, and is longer than the length of a foreign substance expected to be attached to the opposing plate, and the driving means The recording medium on the transport path and the opposing plate may be moved relative to each other by a predetermined multiple of a predetermined length.

  The drive means may include a motor. The processor drives the motor to cancel the operation in the predetermined period after the predetermined period has elapsed, and further drives the motor to ensure that the motor shaft of the motor and the gear mesh with each other. May be

  The lines of multiple colors may be composed of colored lines and white lines alternating with one another. Each of the plurality of color lines may have a predetermined length in the first direction. The processor detects a first detection output which is a detection output of the sensor when there is no recording medium between the sensor and the opposing plate, and a second detection output which is a detection output of the sensor corresponding to a predetermined period. The result of the comparison may be used.

  The processor detects the second detection output as the first detection when the second detection output changes relative to the first detection output in a portion corresponding to the innermost position in the first direction of the coloring line. The position moved in the first direction by the distance of relative movement from the outermost position changed with respect to the output is configured to be determined as the position of the end in the first direction with respect to the white recording medium. May be

  The processor detects, on the white recording medium, the innermost position at which the second detection output changes in a predetermined period in the outermost colored line in which the second detection output changes with respect to the first detection output. It may be configured to be determined as the position of the end of the first direction.

  The processor detects that the second detection output is the first detection when the second detection output changes relative to the first detection output in a portion corresponding to the innermost position in the first direction of the white line. The position moved in the first direction by the distance of relative movement from the outermost position changed with respect to the output is configured to be determined as the position of the end in the first direction with respect to the colored recording medium It may be done.

  The processor records, in the outermost white line in which the second detection output has changed relative to the first detection output, a colored recording of the innermost position where the second detection output has changed in a predetermined period. It may be configured to determine the position of the end in the first direction of the medium.

  The image processing apparatus may further include an image processing unit that processes an image formed on a recording medium. The image processing unit may be configured to adjust the position in the first direction of the image formed on the recording medium based on the position of the end of the recording medium in the first direction.

  The processor may be configured to cause the driving means to adjust the position of the recording medium in the first direction based on the position of the end of the recording medium in the first direction.

  The image forming apparatus may further include a registration roller for controlling conveyance of the recording sheet on the conveyance path. The driving means moves the first recording medium in the first direction by moving the resist roller to one side in the first direction during a predetermined period with respect to the first recording medium, and the first recording medium Is configured to move the second recording medium in the first direction by moving the resist roller to one side in the first direction during a predetermined period with respect to the second recording medium conveyed next to the It may be

  The processor determines, based on the detection output of the sensor, whether or not foreign matter is present on the transport path, and if it is determined that foreign matter is present on the transport path, in the first direction, no foreign matter is present. Also, the size may be longer than the size of the foreign matter, and the recording medium and the counter plate may be relatively moved.

  When the foreign matter is located at the end of the line first direction, the processor moves the recording medium relative to the opposing plate relatively longer than the size of the foreign matter than when there is no foreign matter, and the foreign matter is a line When not positioned at the end in the first direction, the recording medium and the opposing plate may be moved relative to each other by the same dimension as in the case where there is no foreign matter.

  According to the present disclosure, the driving means relatively moves the recording medium and the counter plate in the predetermined period, and the processor uses the output of the sensor detected in the predetermined period to detect the end of the recording medium. Determine the position. Accordingly, it is an object of the present invention to provide a technique for detecting the positional deviation of the recording medium in the direction intersecting the conveying direction without requiring a long time for conveying the recording medium.

FIG. 1 is an overall configuration diagram of an image processing apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a mechanism for vibrating a recording medium in the image processing apparatus 100. FIG. 2 shows a partial hardware configuration of an image processing apparatus 100. It is a figure for demonstrating the structure of the opposing board 200. FIG. FIG. 6 schematically shows detection outputs of light receiving elements of the line sensor 25 when the recording material P is located at a position facing the line sensor 25. FIG. 6 schematically shows detection outputs of light receiving elements of the line sensor 25 when the recording material P is located at a position facing the line sensor 25. FIG. 6 is a diagram for explaining a detection mode of the end portion of the recording material in the present embodiment. FIG. 6 is a diagram for explaining a detection mode of the end portion of the recording material in the present embodiment. (A) and (B) are figures for demonstrating the detection aspect of the edge part of the recording material in this Embodiment. (A) and (B) are figures for demonstrating the other example of a change of the integrated value of the light reception amount of a light receiving element by a recording material being shaken. (A) and (B) are figures for demonstrating the further another example of a change of the integrated value of the light reception amount of a light receiving element by a recording material being shaken. FIG. 7 is a view showing a specific example of the method of determining the end portion of the recording material P. FIG. 7 is a view showing a specific example of the method of determining the end portion of the recording material P. FIG. 7 is a view showing a specific example of the method of determining the end portion of the recording material P. FIG. 7 is a view showing a specific example of the method of determining the end portion of the recording material P. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 6 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the facing plate 200. FIG. 7 is a diagram showing an example of a sequence of control of peristalsis for two continuous recording materials P. It is a figure which shows an example of the control sequence of a comparative example.

  Hereinafter, embodiments of an image processing apparatus will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, these descriptions will not be repeated.

[1. Basic Configuration of Image Processing Device]
FIG. 1 is an overall configuration diagram of an image processing apparatus according to the present embodiment. The image processing apparatus 100 includes an image output unit 1P, a reader unit 4, and an operation unit 5. The reader unit 4 and the operation unit 5 are provided on the image output unit 1P. The operation unit 5 is integrally configured with a display unit such as a display in addition to buttons operated by the user, and also functions as a touch panel. The user can use the operation unit 5 to set various settings of the image forming process, for example, the paper type of the recording material P used for image formation.

  In the present embodiment, the recording material P is an example of a recording medium conveyed in the image processing apparatus. In the present specification, conveyance of the recording material P will be mainly described as conveyance of the recording medium, but the recording medium may be a document sheet conveyed in the image processing apparatus.

  The reader unit 4 functions as a scanner for reading an original image. The reader unit 4 reads an original image according to an instruction from the operation unit 5, generates image data of the read original image, and transmits the image data to the image output unit 1P. The image output unit 1P performs an image forming process in accordance with the instruction from the operation unit 5 and the image data transmitted from the reader unit 4.

  The image output unit 1P roughly includes an image forming unit 10, a sheet feeding unit 20, an intermediate transfer unit 30, a fixing unit 40, a reverse double-sided unit 50, a double-sided conveyance unit 60, a paper discharge unit 70, and a control unit 80. The image forming unit 10 includes four stations having the same configuration.

  The image forming unit 10 includes photosensitive drums 11a to 11d, which are image carriers that are rotationally driven in the direction of the arrow in the drawing. Primary chargers 12a to 12d, optical systems 13a to 13d, and developing units 14a to 14d are disposed at positions facing the outer peripheral surfaces of the photosensitive drums 11a to 11d, in the rotational direction of the photosensitive drums 11a to 11d. Ru. Hereinafter, when the photosensitive drums 11a to 11d, the primary chargers 12a to 12d, the optical systems 13a to 13d, and the developing devices 14a to 14d are not distinguished, the photosensitive drum 11, the primary charger 12, the optical system 13, the developing device Write 14

  The primary charger 12 uniformly charges the surface of the photosensitive drum 11. The optical system 13 forms an electrostatic latent image on the photosensitive drum 11 by irradiating the charged photosensitive drum 11 with a light beam such as a laser beam modulated according to image data. A yellow electrostatic latent image is formed on the photosensitive drum 11d according to yellow image data. A cyan electrostatic latent image is formed on the photosensitive drum 11c in accordance with cyan image data. A magenta electrostatic latent image is formed on the photosensitive drum 11b in accordance with the magenta image data. A black electrostatic latent image is formed on the photosensitive drum 11a in accordance with the black image data.

  The electrostatic latent image formed on the photosensitive drum 11 is developed by the toner stored in the developing unit 14. As a result, a toner image is formed on the photosensitive drum 11. The electrostatic latent image formed on the photosensitive drum 11d is supplied with yellow toner from the developing device 14d, and is visualized as a yellow toner image. The electrostatic latent image formed on the photosensitive drum 11c is supplied with cyan toner from the developing device 14c and is visualized as a cyan toner image. The electrostatic latent image formed on the photosensitive drum 11b is supplied with magenta toner from the developing device 14b, and is visualized as a magenta toner image. The electrostatic latent image formed on the photosensitive drum 11a is supplied with black toner from the developing device 14a and is visualized as a black toner image. A cleaner 15 for cleaning the surface of the photosensitive drum 11 is disposed downstream of the photosensitive drum 11 in the rotational direction.

  The sheet feeding unit 20 includes a sheet feeding cassette 21 for storing a recording material P such as a sheet on which an image is formed. As the recording material P, plain paper or OHT (Overhead Transparency) sheet can be used. The recording material P stored in the sheet feeding cassette 21 is conveyed toward the intermediate transfer unit 30. For that purpose, the sheet feeding unit 20 picks up the recording material P from the sheet feeding cassette 21 sheet by sheet, and a plurality of conveyance roller pairs for conveying the recording material P picked up by the pickup roller pair 22 to the registration roller pair 26 And a conveyance guide 24. In the present embodiment, the transport guide 24 is an example of a transport path.

  In the conveyance path on the upstream side of the recording material P conveyance direction of the registration roller pair 26, the recording material P in the direction (width direction of the recording material) orthogonal to the conveyance direction of the recording material P and its end (lateral end) A line sensor 25 for detecting the position is provided. The registration roller pair 26 shifts the recording material P to a predetermined position in the width direction by shifting in the width direction of the recording material P detected by the line sensor 25 in a state in which the recording material P is sandwiched. The resist roller pair 26 sends the recording material P to the intermediate transfer unit 30 in accordance with the timing of image formation in the image forming unit 10.

In the present specification, shifting the recording material P in the width direction is also referred to as "perfusion".
A registration front roller pair 27 is disposed on the upstream side of the registration roller pair 26 in the conveyance direction of the recording material P. The pre-registration roller pair 27 can be controlled to a state in which the recording material P is nipped and a state in which the nipping is released.

  A sheet sensor 28 for determining the presence or absence of the recording material P on the conveyance guide 24 is disposed at a position facing the conveyance guide 24 with the line sensor 25 interposed therebetween.

  The image processing apparatus 100 further includes an opposing plate 200. The opposing plate 200 and the line sensor 25 oppose each other with the conveyance guide 24 interposed therebetween. In the counter plate 200, white lines and black lines are alternately arranged. The detailed configuration of the counter plate 200 will be described later with reference to FIG.

  A conveyance sensor 29 a that detects the recording material P on the conveyance guide 24 is provided on the conveyance path downstream of the registration roller pair 26 in the conveyance direction of the recording material P. At a position opposite to the conveyance sensor 29a with the conveyance guide 24 interposed therebetween, a prism 29b for returning the irradiation light from the conveyance sensor 29a is provided. The sheet sensor 28, the resist roller pair 26, the line sensor 25, and the conveyance sensor 29a are collectively referred to as a "resist portion".

  The intermediate transfer unit 30 includes an intermediate transfer belt 31 as an intermediate transfer member. The intermediate transfer belt 31 is wound around a drive roller 32, a tension roller 33 biased by an elastic member (not shown) to apply appropriate tension to the intermediate transfer belt 31, and a secondary transfer roller 34. The drive roller 32 rotationally drives the intermediate transfer belt 31.

  Primary transfer rollers 35a to 35d forming primary transfer areas Ta, Tb, Tc, and Td in pairs with the photosensitive drums 11a to 11d at positions facing the photosensitive drums 11a to 11d with the intermediate transfer belt 31 interposed therebetween. Be placed. At a position facing the secondary transfer roller 34 with the intermediate transfer belt 31 interposed therebetween, a secondary transfer roller 36 that forms a secondary transfer area Te in a pair with the secondary transfer roller 34 is disposed. A cleaner 37 for cleaning the image forming surface of the intermediate transfer belt 31 is disposed on the downstream side of the rotation direction of the intermediate transfer belt 31 in the secondary transfer area Te.

  The fixing unit 40 guides the recording material P to a fixing roller 41a having a heat source such as a halogen heater inside, a pressure roller 41b pressurized by the fixing roller 41a, and a nip portion between the fixing roller 41a and the pressure roller 41b. A pre-fixing roller pair 42 and a pre-fixing guide 43 are provided. The pressure roller 41b may be configured to include the same heat source as the fixing roller 41a.

  The discharge unit 70 includes an inner discharge roller pair 71 for conveying the recording material P heat-fixed by the fixing unit 40, an outer discharge roller pair 72 for discharging the recording material P to the outside, and the reverse surface 50 and the outside of the recording material P. A flapper 73 leading to either of the discharge roller pair 72 is provided. The reversing duplex portion 50 includes a plurality of reverse reversing double-sided roller pairs 51 and reverse reversing double-sided guides 52 that can rotate in forward and reverse directions. Further, the reverse duplexing unit 50 guides the recording material P reversed by the reverse duplexing guide 52 to the outer discharge roller pair 72 at the time of reverse discharge, and both sides which guide the recording material P to the duplex transport unit 60 at the time of duplex printing. A flapper 54 is provided. The double-sided conveyance unit 60 includes a plurality of double-sided conveyance roller pairs 61 for conveying the recording material P from the reverse double-sided unit 50 to the paper supply unit 20 and a double-sided conveyance guide 62 for guiding the recording material P. The control unit 80 controls operations of the above-described units (the image forming unit 10, the sheet feeding unit 20, the intermediate transfer unit 30, the fixing unit 40, the reverse double-sided unit 50, the double-sided conveyance unit 60, and the paper discharge unit 70). , CPU (Central Processing Unit) and motor drive board.

  In the image processing apparatus 100 having such a configuration, when an instruction for image formation is input from the operation unit 5, the pickup roller pair 22 takes out the recording material P one by one from the sheet feeding cassette 21. The taken-out recording material P is conveyed by the plurality of conveyance roller pairs 23 to the registration roller pair 26 through the pre-registration roller pair 27. At this time, the resist roller pair 26 is stopped. In this state, the recording material P is abutted against the registration roller pair 26 to form a loop of the recording material P, thereby correcting the skew of the recording material P. Thereafter, in accordance with the timing of image formation of the image forming unit 10, the registration roller pair 26 starts to rotate.

  In the image forming unit 10, a toner image is formed on the photosensitive drum 11d most upstream in the rotational direction of the intermediate transfer belt 31 according to the process described above in response to an instruction for image formation from the operation unit 5. The toner image formed on the photosensitive drum 11d is transferred to the intermediate transfer belt 31 in the primary transfer area Td by the primary transfer roller 35d to which a high voltage is applied. The toner image transferred onto the intermediate transfer belt 31 is conveyed to the next primary transfer area Tc. A toner image is formed on the photosensitive drum 11c at the timing when the toner image transferred onto the intermediate transfer belt 31 in the primary transfer area Tc is conveyed. In the primary transfer area Tc, the toner image formed on the photosensitive drum 11c is transferred onto the toner image transferred in the primary transfer area Td. Thereafter, similarly, transfer is performed in the primary transfer areas Tb and Ta, whereby a full-color toner image is formed on the intermediate transfer belt 31.

  The recording material P conveyed by the rotation of the registration roller pair 26 passes on the conveyance sensor 29a. The conveyance sensor 29a detects the recording material P passing through. In accordance with the detection timing, the rotational speed of the pair of resist rollers 26 is adjusted so that the toner image transferred onto the intermediate transfer belt 31 and the image forming position on the recording material P coincide with each other in the secondary transfer area Te. Ru.

  When a full color toner image is formed on the intermediate transfer belt 31, the recording material P is conveyed to the secondary transfer area Te. When the recording material P enters the secondary transfer region T2 and contacts the intermediate transfer belt 31, a high voltage is applied to the secondary transfer roller 36 in accordance with the passage timing of the recording material P. Thus, a full color toner image on the intermediate transfer belt 31 is transferred to the recording material P.

  The recording material P on which the toner image has been transferred is guided by the pre-fixing guide 43 to the nip portion between the fixing roller 41 a and the pressure roller 41 b of the fixing unit 40. The toner image is fixed on the surface of the recording material P by the heat and the pressure of the nip by the fixing roller 41 a and the pressure roller 41 b of the fixing unit 40. The recording material P on which the toner image is fixed is conveyed by the inner discharge roller pair 71, and is conveyed toward the reverse both-side portion 50 by the flapper 73 at the time of reverse discharge and reverse printing at the time of double-sided printing. The recording material P on which the toner image is fixed is conveyed by the flapper 73 in the direction of the outer discharge roller pair 72 after printing on the back side in single-sided printing or double-sided printing. The outer discharge roller pair 72 discharges the recording material P to the outside of the image output unit 1P.

  The recording material P conveyed to the reverse both-side portion 50 is pulled into the back of the reverse double-sided guide 52 by the plurality of reverse double-sided roller pairs 51 and is stopped. Thereafter, the plurality of reverse double-sided roller pairs 51 are reversely rotated, and the recording material P is guided by the double-sided flapper 54 to the outer discharge roller pair 72 in the case of reverse sheet discharge, and to the double-sided conveyance unit 60 in double-sided printing. In the case of reverse sheet ejection, the recording material P is guided to the outer discharge roller pair 72 by the sheet discharge flapper 53 after passing through the double-sided flapper 54, and is discharged to the outside of the image output unit 1P by the outer discharge roller pair 72. During double-sided printing, the recording material P is conveyed by a plurality of double-sided conveyance roller pairs 61, guided by the double-sided conveyance guide 62, and merged with the conveyance guide 24 of the paper feeding unit 20. Thereafter, the recording material P is discharged to the outside of the image output unit 1P by the outer discharge roller pair 72 through the same process as the surface printing.

[2. Mechanism for vibrating recording medium]
FIG. 2 is a view showing an example of a mechanism for swinging the recording medium in the image processing apparatus 100. As shown in FIG. FIG. 2 schematically shows a cross section of the mechanism.

  In FIG. 2, the transport guide 24 is omitted. As shown in FIG. 2, the recording material P is transported between the line sensor 25 and the counter plate 200. An arrow C represents the transport direction of the recording material P. In the following description, the direction represented by the arrow C is also referred to as the “transport direction C”.

  In the image processing apparatus 100, the tip of the recording material P is nipped by the registration roller pair 26 when the tip of the recording material P passes a position facing the line sensor 25. The rotation of the resist roller pair 26 in the arrow R direction is driven by the registration drive motor 305. For example, the control unit 80 rotates the registration drive motor 305 to rotate the registration roller pair 26, thereby conveying the recording material P. The control unit 80 stops the rotation of the registration roller pair 26 by stopping the rotation of the registration drive motor 305, for example, and thereby causes the registration roller pair 26 to sandwich the recording material P.

  In the image processing apparatus 100, the shift motor 306 moves the registration roller pair 26 in the depth direction in FIG. The control unit 80 causes the registration roller pair 26 to swing the recording material P in the depth direction (width direction) in FIG. 2 by appropriately controlling the registration drive motor 305 and the shift motor 306.

[3. Partial Hardware Configuration of Image Processing Device]
FIG. 3 is a diagram showing a partial hardware configuration of the image processing apparatus 100. As shown in FIG. The portion shown in FIG. 3 includes at least a part of the hardware configuration regarding the peristalsis of the recording material P. The operation of the unit involved in the skew correction and the lateral registration correction will be described with reference to FIG.

  The CPU 301 is included in the control unit 80 (FIG. 1). The CPU 301 obtains an instruction from the input device of the operation unit 5, and displays information on the display device of the operation unit 5. The CPU 301 acquires size information indicating the size of the recording material P (eg, A4, A4R, postcard, name card, specific length in the conveyance direction and width direction, etc.) from the operation unit 5 or the size sensor 314.

  The size sensor 314 is provided on the conveyance path or the sheet feeding cassette 21 and detects the size of the recording material P. When the sheet sensor 28 outputs a detection signal, the CPU 301 recognizes that the leading end of the recording material P has reached the sheet sensor 28. The CPU 301 stops the rotation of the pre-registration drive motor 307 on the basis of the timing when the leading end of the recording material P reaches the sheet sensor 28, and starts the skew correction and the lateral registration correction.

  The CPU 301 controls, via the motor control unit 330, a pre-registration drive motor 307 for rotating the pre-registration roller pair 27 and an open / close motor 308 for opening the pre-registration roller pair 27 when shifting the registration roller pair 26. . The CPU 301 determines the shift amount (distance α) in the lateral registration correction, and restarts the rotation of the registration driving motor 305 via the motor control unit 330 when the rotation restart timing of the registration roller pair 26 is reached. Further, the CPU 301 drives the shift motor 306 via the motor control unit 330 so that the recording material P moves in the lateral direction by the distance α.

  The CPU 301 uses the LED 315 as a light source and the line sensor 25 to determine the lateral end position of the recording material P. That is, the CPU 301 functions as a position detection unit that detects the lateral end position of the sheet.

  When driving the line sensor 25, the CPU 301 outputs a trigger signal TRG to the line sensor control unit 302. When the trigger signal TRG is input, the line sensor control unit 302 outputs a control signal necessary to drive the line sensor 25 to the line sensor 25. As the control signal, there are a clock signal CLK, a start pulse SP, an LED control signal LED_CONT for lighting the LED 315 attached to the line sensor and adjusting the light amount. When the clock signal CLK and the start pulse SP are input, the line sensor 25 sequentially reads out the signals output from the respective pixels of the line sensor 25 and outputs a time-series output signal OUT. The output signal OUT is an analog signal and is input to the analog processor 303 and the comparator 310.

  The analog processor 303 converts the output signal OUT from an analog signal to a digital signal and outputs the digital signal to the CPU 301. The CPU 301 determines the area of the read pixel of the line sensor 25 that performs the light amount adjustment of the LED 315 based on the size information of the width direction of the sheet acquired from the size sensor 314 or the operation unit 5. That is, the CPU 301 functions as a light amount adjustment area determination unit. An output signal OUT from the line sensor 25 is input to the analog processor 303, converted into a digital signal, and input to the CPU 301. The line sensor control unit 302 drives the LED 315 with a plurality of predetermined light amounts (drive currents), and based on the level of the reflected light amount at each drive current, an output signal output from the pixel of the previously determined area The light quantity of the LED 315 is adjusted so that the maximum value of the light quantity becomes a predetermined value. That is, the line sensor control unit 302 functions as a light amount adjustment unit. The function of the line sensor control unit 302 may be provided in the CPU 301.

  After the light amount adjustment is completed, the CPU 301 compares the levels of the output signals from the line sensor 25 to determine the maximum value Vh and the minimum value Vl, and determines an intermediate value between the maximum value and the minimum value as the threshold value Vth. Do. The maximum value Vh is an output from the read pixel facing the sheet, and the minimum value Vl is an output from the read pixel not facing the sheet. The CPU 301 outputs the threshold value Vth to the D / A converter 309. That is, the CPU 301 functions as a threshold determination unit. The D / A converter 309 outputs a voltage corresponding to the threshold value Vth to the comparator 310. The comparator 310 performs binarization by comparing the threshold value Vth with the output signal OUT.

  As described above, the comparator 310 functions as a binarizing unit that binarizes the signal by comparing the signals output from the plurality of pixels of the line sensor 25 with the determined threshold value. If the output signal OUT exceeds the threshold value Vth, the comparator 310 outputs a high level signal. If the output signal OUT does not exceed the threshold value Vth, the comparator 310 outputs a low level signal. The counter 311 is operated by the clock signal CLK output from the line sensor control unit 302. The counter 311 counts the time during which the binarized signal is at high level in accordance with the clock signal CLK, and outputs the count value to the CPU 301. The CPU 301 determines the lateral end position of the recording material P based on the count value.

  The image processing apparatus 100 may be configured such that each light receiving element of the line sensor 25 can detect the amount of received light at a plurality of levels. That is, the light receiving element may be configured to output a signal according to the length of time when light having a predetermined amount or more is received. In one example, each light receiving element outputs a signal corresponding to the length of time of receiving the reflected light from the recording material P or the white line within 5 ms.

  Furthermore, the CPU 301 calculates the amount and direction of deviation of the lateral end position with respect to the target position. The CPU 301 converts the shift amount into the number of pulses of the shift motor 306, and outputs data of the number of pulses and the driving direction for driving the shift motor 306 to the motor control unit 330. The motor control unit 330 drives the shift motor 306 according to the drive direction and the number of pulses.

[4. Configuration of opposing plate]
FIG. 4 is a diagram for explaining the configuration of the counter plate 200. As shown in FIG. Referring to FIG. 4, the opposing plate 200 is fitted in the transport guide 24. The line sensor 25 is disposed to face the opposing plate 200. The recording material P is transported so as to pass near the center of the transport guide 24 in one example. Thus, in the recording material P, the end on one side of the recording material P in the direction intersecting the transport direction C (the direction represented by the arrow X in FIG. 4. Hereinafter, also referred to as “width direction X”) Pass through. The line sensor 25 covers the one end of the recording material P in the width direction X.

  In FIG. 4, the position PO represents the outermost position in the width direction X, and the position PI represents the center in the width direction X.

  White lines and black lines are alternately drawn on the surface of the opposite plate 200 facing the recording material P. In FIG. 4, two of the plurality of white lines are shown as white lines 202 and 204. Two of the plurality of black lines are shown as black lines 201 and 203.

  Black lines are an example of coloring lines. The coloring line may be colored in a color different from that of the white line. For example, the color to be colored may be other than black as long as the amount of light received by reflection is differentiated with respect to the white line.

  Each of the white line and the black line has a predetermined length in the width direction X. The predetermined length is, for example, an integral multiple of the pixel of the light receiving element of the line sensor 25. It is preferable that the distance of the relative movement between the facing plate 200 and the recording material P in the width direction X in the above-mentioned “perturbation” is equal to or more than the above-mentioned predetermined length. Note that the distance of relative movement between the facing plate 200 and the recording material P in the width direction X in the above “perfusion” is an integral multiple of the dimension in the width direction X of the white line (or black line). Is preferred.

  The line sensor 25 includes a plurality of sets of light emitting elements and light receiving elements corresponding to the white and black lines of the counter plate 200, respectively. Each light receiving element detects the amount of light (amount of light received) of the reflected light from the opposing plate 200 side. Thereby, the respective positions of the white line and the black line adjacent to each other are distinguished by the detection output of each light receiving element. In one example, 10 sets of light emitting elements and light receiving elements are arranged for one line in the counter plate 200. However, the number of sets is merely an example.

[5. Description of line sensor output]
The line sensor 25 includes a plurality of light emitting elements aligned in the width direction X and a plurality of light receiving elements aligned in the width direction X. 5 and 6 schematically show detection outputs of the respective light receiving elements of the line sensor 25 when the recording material P is located at a position facing the line sensor 25. FIG. FIG. 5 shows the detection output when the recording material P is a white sheet and the end of the recording material P does not include an image colored in black or the like. FIG. 6 shows the detection output when the recording material P is a white sheet and the end of the recording material P includes an image colored in black or the like.

  In FIG. 5, the item “line sensor output” represents the detection output of the light receiving element at the position corresponding to each line on the counter plate 200. The H signal is a signal corresponding to a white surface. The L signal is a signal corresponding to a black surface (or a colored surface). In the example of FIG. 5, a part of the black line 203 is covered by the recording material P. Thus, in the detection output corresponding to the black line 203, the value of the signal corresponding to the portion not covered by the recording material P is L, and the value of the signal corresponding to the portion covered by the recording material P is It is H.

  In the example of FIG. 5, the portions facing the white line 202 and the black line 201 are covered by the recording material P. Thus, the value of the signal corresponding to the entire area of the white line 202 and the black line 201 is H.

  A reference signal is stored in the storage device 320 (FIG. 3). The reference signal is a signal of the light receiving element when the recording material P is not present at a position facing the line sensor 25.

  The comparison signal represents the result of comparing the line sensor output with the reference signal. If the line sensor output and the reference signal have the same value, the value of the comparison signal is L. If the line sensor output and the reference signal have different values, the value of the comparison signal is H. In the image processing apparatus 100, the CPU 301 determines the position of the end of the recording material P by determining the portion where the value of the comparison signal is H.

  In the example of FIG. 5, the position in the width direction corresponding to the comparison signal is shown. The position PO represents a position corresponding to the outermost part in the width direction X of the transport guide 24. The CPU 301 determines the position of the end of the sheet using the position where the value of the comparison signal indicates H and is the outermost (closer to the position PO) position. In the example of FIG. 5, the position x1 at which the value of the comparison signal indicates H and the outermost position is determined as the end of the recording material P.

  In the example of FIG. 6, the image IM is disposed on the recording material P. The image IM is colored in a color other than white. Thereby, in the white recording material P, the light reflectance of the portion where the image IM is formed is lower than the portion where the image IM is not formed. It is located at one end of the recording material P. Thus, although the end of the recording material P is positioned at the center of the black line 203, the value of the line sensor output is L over the entire area of the black line 203. Although the actual position of the end of the recording material P is the position x1, the position x2 may be determined as the position of the end.

[6. Detection mode of the present embodiment]
7 to 9 are diagrams for explaining the detection mode of the end portion of the recording material P in the present embodiment. In the present embodiment, the CPU 301 drives the shift motor 306 during a single light reception period (for example, 5 ms (from time T0 to time T1 in FIG. 8)) of the light receiving element of the line sensor 25. Thereby, the resist roller pair 26 moves the recording material P in the width direction X during the light reception period. That is, the recording material P moves in the width direction X while the light receiving element detects the light receiving amount.

  The moving distance of the recording material P is equal to or greater than the width of each line on the counter plate 200. As a result, even if the end of the recording material P is colored and the portion (such as the image IM in FIG. 6) is located on the black line, the portion is moved on the white line by the movement during the light reception period. Move to Thereby, the end is detected in the comparison signal.

  In FIG. 7, a recording material P1 represents a state before movement (perspiration), and a recording material P2 represents a state after movement (perspiration). In the image processing apparatus 100, the recording material P and the counter plate 200 may be moved relative to each other during the light reception period. Therefore, instead of the recording material P, the opposing plate 200 may be moved in the width direction X. The recording material P may be moved to one side in the width direction X, and the opposing plate 200 may be moved to the other side in the width direction X.

  In FIG. 7, the item “integrated value” represents an integrated value of the light receiving amount of each light receiving element in the light receiving period in a state where the recording material P is located at a position facing the line sensor 25. The item “reference signal” represents the integrated value of the light receiving amount of each light receiving element in a period of the same length as the above period when the recording material P is not at the position facing the line sensor 25.

  The integrated value “V10” is a value when the light receiving element continues to receive the reflected light from the white line or the white recording material P in the light receiving period. The integrated value being 0 (zero) means that the light receiving element continued to face the black line or the colored image in the light receiving period.

  In FIG. 7, the item “reference signal” represents the integrated value of the light receiving amount of each light receiving element with no recording material P and having the same length of time as the light receiving period.

  In FIG. 7, the item “comparison signal” represents the result of comparison of the item “integrated value” and the item “reference signal” for each light receiving element. In the item "comparison signal", the value "H" indicates that there is a difference in value between the item "integrated value" and the item "reference signal". The value "L" indicates that there is no difference in value between the item "integrated value" and the item "reference signal".

  In the example of FIG. 7, the end of the recording material P is determined using the position closest to the position PO (the outer edge of the conveyance guide 24) among the portions indicating the value H of the comparison signal. The position x1 is a position where the value of the comparison signal is H and is the position closest to the position PO. The position x0 is a position moved from the position x1 to the position PI side by the length in which the recording material P is oscillated. The position x0 is determined as the position of the end of the recording material P.

  FIG. 8 shows a timing chart in control for detecting the end of the recording material P. In the timing chart, the item “LED lighting” relates to the lighting state of the light emitting element of the line sensor 25 (for example, LED (Light Emitting Diode). H signal represents lighting of the light emitting element. L signal represents the light emitting element). Indicates the light off.

  The item “reception of light reception amount” relates to reading of the light reception amount (detection output) of the light receiving element of the line sensor 25. The H signal indicates that a read is being performed. An L signal indicates that a read has not been performed.

  The item “CPU calculation” relates to a calculation for determining the position of the end of the recording material P (or the shift amount of the position from the reference position to the end) using the detection output of the light receiving element by the CPU 301. The H signal indicates that the operation is being performed. The L signal indicates that the operation is not being performed (or that the CPU 301 is performing another operation).

  The item “perturbation direction” relates to the direction of peristalsis of the recording material P by the registration roller pair 26, that is, the rotation direction of the shift motor 306. The direction of rotation is switched, for example, by the CPU 301 switching the gear of the shift motor 306. The -direction represents one direction in the width direction X (for example, the direction in which the recording material P is moved outward in the conveyance guide 24). The + direction indicates the other direction in the width direction X (for example, the direction in which the recording material P is moved to the central portion in the conveyance guide 24).

  The item “shift motor” relates to whether or not the shift motor 306 is driven. The ON signal indicates that the shift motor 306 is rotationally driven. The OFF signal indicates that the shift motor 306 is stopped.

  In the example of FIG. 8, the light emitting element of the line sensor 25 is lit in a period (5 ms) from time T0 to time T1. Further, when the CPU 301 rotates the shift motor 306, the registration roller pair 26 moves the recording material P in the width direction X by a predetermined distance (a distance D1 described later). The light receiving element of the line sensor 25 accumulates the amount of light received during the period. That is, in a state where the recording material P is continuously moved in the width direction X during a period from time T0 to time T1, the light receiving element of the line sensor 25 continuously accumulates the light reception amount.

  During a period from time T1 to time T2 (5 ms), the CPU 301 reads the accumulated amount of light reception in the period from time T0 to time T1 from each light receiving element.

  During the period from time T2 to time T3 (1 ms), the CPU 301 determines the position of the end portion of the recording material P using the light reception amount read from each light receiving element, and the deviation amount of the position of the end portion from the reference position decide.

  The CPU 301 eliminates the deviation of the recording material P in the period from time T3 to time T4. More specifically, the CPU 301 sets the peristaltic direction as necessary, and rotates the shift motor 306 for a necessary time. In one example, the CPU 301 determines the position of the end of the recording material P in the width direction X using the detection output of the light receiving element of the line sensor 25 and determines the amount of deviation of the recording material P in the width direction X . Furthermore, the CPU 301 determines the peristaltic direction and the movement amount to eliminate the deviation amount. Then, at time T3, the CPU 301 sets the rotational direction of the shift motor 306 to rotate in the determined peristaltic direction (item "peripheral direction"), and shifts the shift motor 306 for a time corresponding to the determined movement amount. Rotate. Thus, the registration roller pair 26 moves in the width direction X by an amount that cancels the deviation in a state in which the recording material P is sandwiched.

  (A) of FIG. 9 and (B) of FIG. 9 are diagrams for explaining an example of the change of the integrated value of the light receiving amount of the light receiving element due to the recording material P being shaken. (A) of FIG. 9 represents the state 0.5 ms after time T0. (B) of FIG. 9 represents the state 1.0 ms after time T0. In (A) in FIG. 9 and (B) in FIG.

  In FIG. 9A, the item “amount of light received” represents the amount of light received by each light receiving element. The item "integrated value of light reception amount" represents an integrated value of the light reception amount of each light receiving element. In the example of FIG. 9A, the end of the recording material P is positioned on the black line 203.

  More specifically, ten light receiving elements are arranged to correspond to the black line 203. The ten light receiving elements include first to tenth light receiving elements as shown below.

First light receiving element: detects light at positions x10 to x11 in width direction X second light receiving element: detects light at positions x11 to x12 in width direction X third light receiving element: positions x12 in width direction X Fourth light receiving element: detects light at positions x13 to x14 in the width direction X fifth light receiving element: detects light at positions x14 to x15 in the width direction X Sixth light receiving element : Detects light at positions x15 to x16 in the width direction X seventh light receiving element: detects light at positions x16 to x17 in the width direction X eighth light receiving element: lights at positions x17 to x18 in the width direction X 9th light receiving element to detect: detect light at positions x18 to x19 in the width direction X tenth light receiving element to detect light at positions x19 to x20 in the width direction X In FIG. The recording material P covers from the position x 10 to the position x 15 on the black line 203. The recording material P is a white sheet of paper, and no image is formed on the portion of the recording material P located on the black line 203. Thereby, in the line sensor 25, light from the recording material P is reflected to the first to fifth light receiving elements. The amount of light received by the first to fifth light receiving elements is V1. On the other hand, the light receiving amounts of the sixth to tenth light receiving elements are zero. The integrated value of the light receiving amounts of the first to fifth light receiving elements is also V1. Further, the integrated value of the light receiving amounts of the sixth to tenth light receiving elements is also zero.

  In (B) of FIG. 9, the recording material P is moved in the width direction X as compared with (A) of FIG. 9. The amount of movement is a distance (that is, two pixels) corresponding to the detection region of the two light receiving elements. The recording material P covers from the position x 10 to the position x 17 on the black line 203. Thereby, in the line sensor 25, light from the recording material P is reflected to the first to seventh light receiving elements. The amount of light received by the first to seventh light receiving elements is V1. On the other hand, the black line 203 does not reflect light. Therefore, the light receiving amounts of the eighth to tenth light receiving elements are zero. Taking into consideration (A) of FIG. 9 and (B) of FIG. 9, the integrated value of the light receiving amounts of the first to fifth light receiving elements is V2 (twice the value V1). The integrated value of the light receiving amounts of the sixth to seventh light receiving elements is V1. The integrated value of the light receiving amounts of the eighth to tenth light receiving elements is zero.

  The integrated value of the light reception amount of each of the first to tenth light receiving elements changes depending on from which position the end of the recording material P moves. Based on this principle, the CPU 301 can determine the end portion of the recording material P before moving.

  (A) of FIG. 10 and (B) of FIG. 10 are diagrams for explaining another example of the change of the integrated value of the light receiving amount of the light receiving element due to the recording material P being shaken. A peristalsis of the recording material P for 5 ms (a period from time T0 to time T1 in FIG. 8) is shown in (A) of FIG. 10 and (B) of FIG.

  During the period from time T0 to time T1, the recording material P moves from the position shown in FIG. 10A to the position shown in FIG. Based on the movement of the recording material P, at time T1 ((B) in FIG. 10), the integrated values of the light reception amounts of the plurality of light receiving elements in the area corresponding to the black line 203 are different from each other. The longer the time when the black line 203 is covered by the recording material P, the larger the integrated value.

  (A) of FIG. 11 and (B) of FIG. 11 are diagrams for explaining still another example of the change of the integrated value of the light receiving amount of the light receiving element due to the recording material P being shaken. The peristalsis of the recording material P for 5 ms (period from time T0 to time T1 in FIG. 8) is shown in (A) of FIG. 11 and (B) of FIG. In (A) of FIG. 11 and (B) of FIG. 11, the colored end of the recording material P moves on the white line 202.

  During the period from time T0 to time T1, the recording material P moves from the position shown in FIG. 11A to the position shown in FIG. Based on the movement of the recording material P, at time T1 ((B) in FIG. 11), the integrated values of the light reception amounts of the plurality of light receiving elements in the area corresponding to the white line 202 are different from each other. The longer the time when the white line 202 is covered by the recording material P, the smaller the integrated value.

[7. Specific example of edge determination]
Each of FIGS. 12 to 15 is a view showing a specific example of the method of determining the end portion of the recording material P. FIG. In each of FIGS. 12 to 15, the recording material P1 represents the position of the recording material P before the peristalsis, and the recording material P2 represents the position of the recording material P before the peristalsis. The item “reference signal” represents the integrated value of the light reception amount in the same period as the peristaltic period (or the light reception period) when the line sensor 25 does not face the recording material P. The item “integrated value” represents an integrated value of the light reception amount in a peristaltic period when the line sensor 25 is facing the recording material P. Hereinafter, examples of each of FIGS. 12 to 15 will be described. In the upper part of each figure, the numerical values “0” to “9” attached to each of the black line 201, the white line 202, and the black line 203 indicate the 10 light receiving elements disposed in the region corresponding to each line. It represents each detection area. The meaning of the numerical values “0” to “9” is the same as in each of FIGS. 16 to 20 and 22.

・ Figure 12
In the example of FIG. 12, the recording material P is white, and an image is not formed at the end. During the peristaltic period, the recording material P moves in the width direction X from the position represented as the recording material P1 to the position represented as the recording material P2. During the peristaltic period, basically, the sheet does not move in the transport direction.

  In the example of FIG. 12, the integrated value exhibits a value different from that of the reference signal in a portion (position xa) corresponding to the innermost position (closer to the position PI) in the width direction X of the black line 203. In this case, the CPU 301 moves a position (position x0) moved in the width direction X by a relative movement distance (distance D1) from the outermost position (position x1) at which the integrated value changes with respect to the reference signal. The position of the end portion of the recording material P is determined.

・ Figure 13
In the example of FIG. 13, the recording material P is white, and an image is not formed at the end. During the peristaltic period, the recording material P moves in the width direction X from the position represented as the recording material P1 to the position represented as the recording material P2.

  In the example of FIG. 13, in the white line 202 and the black line 203, the integrated value matches the reference signal. On the other hand, in the example of FIG. 13, the black line having a difference from the reference signal at the outermost side of the conveyance guide 24 is the black line 201. In the portion corresponding to the black line 201, the CPU 301 detects a position (position x0) at the innermost side (closer to the position PI) in the width direction X among the portions in which the integrated value in the peristaltic period changes. Determined as the position of the end in the width direction X with respect to P.

・ Figure 14
In the example of FIG. 14, the recording material P is colored (that is, a sheet of a color other than white). During the peristaltic period, the recording material P moves in the width direction X from the position represented as the recording material P1 to the position represented as the recording material P2.

  In the example of FIG. 14, the integrated value changes with respect to the reference signal in the portion corresponding to the innermost position (position xb) in the width direction X of the white line 202. In this case, the CPU 301 colors the position (position x0) moved in the width direction X by the relative movement distance (distance D1) from the outermost position (position x1) at which the integrated value changes with respect to the reference signal. The position of the end of the recording material P in the width direction X is determined.

・ Figure 15
In the example of FIG. 15, the recording material P is colored (that is, a sheet of a color other than white). During the peristaltic period, the recording material P moves in the width direction X from the position represented as the recording material P1 to the position represented as the recording material P2.

  In the example of FIG. 15, in the black line 203, the integrated value matches the reference signal. In the example of FIG. 15, in the white line 202, the integrated value does not match the reference signal. The CPU 301 sets the position (position x0) at the innermost side (closer to the position PI) of the portion of the white line 202 in which the integrated value has changed in the peristaltic period with respect to the colored recording material P Determined as the position of the end in the width direction X of

  The image processing apparatus 100 indicates that the recording material P to be conveyed is a white recording material or a colored recording material (or a recording material including an image colored at the end). You may receive input of information. The CPU 301 selects whether to determine the position of the end portion of the recording material P according to the aspect shown in FIG. 12 and FIG. 13 or the aspect shown in FIG. 14 or FIG. May be

[8. Specific Example of End Determination when Foreign Matter Exists on Opposite Plate 200]
Each of FIG. 16 to FIG. 22 is a view showing a specific example of the method of determining the end portion of the recording material P when there is a foreign matter on the counter plate 200. In each of FIGS. 16 to 22, the recording material P1 represents the position of the recording material P before the peristalsis, and the recording material P2 represents the position of the recording material P before the peristalsis. Further, the item “reference signal” is a light reception when the line sensor 25 does not face the recording material P and the same period as the peristaltic period in a state in which no foreign matter is guaranteed on the conveyance guide 24 Represents the integrated value of the quantity. In one example, data representing the item “reference signal” is stored in the storage device 320 when the image processing apparatus 100 is shipped. In another example, data representing the item “reference signal” is stored in the storage device 320 by being input from the user.

  The item “prior signal” represents the integrated value of the light reception amount in the same period as the peristaltic period when the line sensor 25 does not face the recording material P in the image processing apparatus 100 in use. The data representing the item “prior signal” is acquired and updated each time the image processing apparatus 100 performs image formation on a predetermined number of recording materials P, for example. The item “integrated value” represents an integrated value of the light reception amount in a peristaltic period when the line sensor 25 is facing the recording material P. Hereinafter, examples of each of FIGS. 16 to 19 will be described.

・ Figures 16 and 17
In the example of FIG. 16, the white paper dust DS adheres on the counter plate 200. Thereby, in the portion corresponding to the paper dust DS, the values of the reference signal and the prior signal are different. That is, when the acquired prior signal includes a portion different from the reference signal, the CPU 301 recognizes that the paper dust DS adheres on the counter plate 200. Paper dust DS is an example of a foreign object.

  When the CPU 301 recognizes that the paper dust DS is attached on the counter plate 200, the display of the operation unit 5 may display a message prompting cleaning.

  When the CPU 301 recognizes that the paper dust DS adheres on the counter plate 200, the peristalsis period (or the time period during which the CPU 301 does not recognize that the paper dust DS adheres on the counter plate 200) In the light reception period, the distance for vibrating the recording material P may be set long. As a result, the position of the leading end of the recording material P is reliably detected either before or after the peristalsis.

  In addition, it is preferable that the moving distance of the recording material P in the width direction X in the above-mentioned "perfusion" is longer than the dimension in the width direction X of an object which is expected to be attached as a foreign substance. In one example, the dimension in the width direction X of the foreign substance assumed in the image processing apparatus 100 is about 0.08 to 1.12 mm. The dimension in the width direction X of one pixel of the light receiving element is about 42.33 μm at 600 dpi. Therefore, it is preferable that the recording material P is moved by about 5 to 10 pixels in the above-mentioned "perfusion".

  The CPU 301 measures the size of the paper dust DS in the width direction X, and lengthens the peristalsis distance by the measured size or more.

  In the example of FIG. 16, the CPU 301 shakes the recording material P by the distance D2 in the peristaltic period. The distance D2 is longer by the distance DX than the distance D1 described with reference to FIG.

  The distance DX is, for example, a distance obtained by adding the distance corresponding to the pixel of one light receiving element of the line sensor 25 to the size of the paper dust DS in the width direction X.

  In one embodiment, the distance D1 is a distance corresponding to 10 pixels. The size of the paper dust DS is a distance corresponding to two pixels. The distance DX is a distance corresponding to one pixel. Thus, the distance D2 is a distance corresponding to 13 pixels.

  In the example of FIG. 16, the position x4 is the position closest to the position PO (outside in the width direction X; see FIG. 4 and the like) in the portion where the reference signal and the integrated value of the light reception amount are different. The CPU 301 determines the position (position x0) moved from the position x4 by the distance D2 as the end portion of the recording material P.

  In the example of FIG. 16, the paper dust DS is located at an end of “outside (closer to the position PO)” of the conveyance guide 24 among the ends of the black line 201. In the example of FIG. 17, the paper dust DS is located at an end of the black line 203 at the “inner side (the side farther from the position PO)” of the conveyance guide 24. Also in the example of FIG. 17, the CPU 301 sets the moving distance of the recording material P in the peristaltic period longer than when the paper dust DS is not detected, as in the example of FIG.

・ Figures 18 and 19
In the example of FIG. 18, the colored stain WP adheres on the counter plate 200. As a result, in the portion corresponding to the dirt WP, the values of the reference signal and the prior signal are different. That is, when the acquired prior signal includes a portion different from the reference signal, the CPU 301 recognizes that the dirt WP adheres on the counter plate 200. The dirt WP is an example of a foreign object.

  When the CPU 301 recognizes that the dirt WP is attached on the counter plate 200, the display of the operation unit 5 may display a message prompting cleaning.

  When the CPU 301 recognizes that the dirt WP is attached on the opposing plate 200, the peristaltic period (or light reception) than when not recognizing that the dirt WP is attached on the opposing plate 200 In the period, the distance for swinging the recording material P may be set long. As a result, the position of the leading end of the recording material P is reliably detected either before or after the peristalsis.

  The CPU 301 measures the dimension of the dirt WP in the width direction X, and lengthens the peristalsis distance by the measured dimension or more.

  In the example of FIG. 18, the CPU 301 vibrates the recording material P by the distance D2 in the peristaltic period. The distance D2 is longer than the distance D1 described with reference to FIG. 12 and the like by the distance DY.

  The distance DY is, for example, a distance obtained by adding the distance corresponding to the pixel of one light receiving element of the line sensor 25 to the dimension of the dirt WP in the width direction X.

  In one embodiment, the distance D1 is a distance corresponding to 10 pixels. The dimension of the dirt WP is a distance corresponding to two pixels. The distance DX is a distance corresponding to one pixel. Thus, the distance D2 is a distance corresponding to 13 pixels.

  In the example of FIG. 18, the position x5 is the position closest to the position PO (outside in the width direction X; see FIG. 4 and the like) in the portion where the reference signal and the integrated value of the light reception amount are different. The CPU 301 determines the position (position x0) moved from the position x5 by the distance D2 as the end portion of the recording material P.

  In the example of FIG. 18, the dirt WP is located at the “outside (closer to the position PO)” end of the transport guide 24 in the white line 202. In the example of FIG. 19, the dirt WP is located at the “inside (the side far from the position PO)” end of the transport guide 24 in the white line 204. Also in the example of FIG. 19, the CPU 301 sets the moving distance of the recording material P in the peristaltic period longer than when the dirt WP is not detected, as in the example of FIG. 18.

・ Fig. 20, Fig. 22
FIGS. 20 and 22 show an example in which no foreign matter is located at the end of the line on the counter plate 200. In such a case, the CPU 301 does not extend the movement distance in the peristaltic period as described with reference to FIGS. 16 to 19.

  More specifically, in the example of FIG. 20, the paper dust DS is located near the center of the black line 201. The paper dust DS is not located at the end of the black line 201 in the width direction X. However, the paper dust DS is located at a position in contact with the end of the recording material P before peristalsis.

  In the case of FIG. 20, the position of the end portion of the recording material P is determined using the aspect of the change of the outermost portion in the width direction X, which is a portion where the light reception amount is changing with respect to the comparison signal. . In the example of FIG. 20, the change of the light reception amount in the region corresponding to the black line 201 with respect to the comparison signal is the change of the outermost part in the width direction X. More specifically, in the region corresponding to the black line 201, the light reception amount is different from the comparison signal in the light reception regions represented as "7" to "9".

  In such a case, the CPU 301 estimates the position of the end portion of the recording material P by using the change in the amount of received light in the light receiving areas “7” to “9”. In one example, as shown in FIG. 21, the CPU 301 estimates the position at which the integrated value of the light reception amount reaches V10, using the inclination of the change in the light reception amount in the light reception regions “7” to “9”. In the example of FIG. 21, the line L21 representing the inclination reaches the value "V10" at the position corresponding to the light receiving area "5". In this case, the CPU 301 determines that the position corresponding to the light receiving area “5” is the position (position x0) of the end of the recording material P.

  In the example of FIG. 22, the paper dust DS is located near the center of the black line 201. The paper dust DS is not located at the end of the black line 201 in the width direction X. The paper dust DS is separated from the end of the recording material P before peristalsis.

  In the case of FIG. 22, the CPU 301 determines the position (position x0) of the end of the recording material P using the position x1 in the same manner as described with reference to FIG.

[9. Specific example of control for continuous recording material]
The image processing apparatus 100 may be configured to shake each of the recording materials P in the same direction during each peristaltic period. FIG. 23 is a diagram showing an example of a sequence of the control of peristalsis for two continuous recording materials P.

  In the example shown in FIG. 23, the period from time T0 to time T4 corresponds to the adjustment of the deviation in the width direction X with respect to the (N−1) th recording material P. The period from time T8 to time T12 corresponds to the adjustment of the deviation in the width direction X with respect to the Nth recording material P. The period from time T4 to time T8 corresponds to the adjustment of the biting of the shift motor.

  Compared to the example shown in FIG. 8, in the example of FIG. 23, the N-1th recording material P is further conveyed in the conveyance direction C after the deviation in the width direction X is corrected at time T4. Be done. As a result, at time T5, the (N−1) th recording material P passes a position facing the line sensor 25.

At time T8, the N-th recording material P reaches a position facing the line sensor 25.
From time T5 to time T6, the CPU 301 has the same length as the time from time T3 to time T4 in the opposite direction to that from time T3 to time T4 (that the value of "perfusion direction" is opposite). The shift motor 306 is rotated for a period. As a result, the pair of registration rollers 26 moved in the width direction X for the purpose of eliminating the deviation of the recording material P returns to the original position.

  After that, the CPU 301 further rotates the shift motor 306 in the same direction as that from time T5 to time T6 from time T6 to time T7. Thus, at time T8, the shift motor 306 can start driving with the motor shaft and the gear reliably engaged.

[10. Comparative example]
FIG. 24 is a diagram illustrating an example of a control sequence of the comparative example. In the example of FIG. 24, the CPU 301 needs two detection outputs of the line sensor 25 for one recording material P. In FIG. 24, the period from time T0 to time T13 relates to the first detection output. The period from time T13 to time T17 relates to the second detection output.

  More specifically, the CPU 301 turns on the light emitting element of the line sensor 25 from time T0 to time T11. The CPU 301 reads the amount of light received from time T0 to time T11 from the light receiving element of the line sensor 25 from time T11 to time T12. The CPU 301 stores the amount of light received by each light receiving element in the storage device 320 from time T12 to time T13.

  The CPU 301 drives the shift motor 306 to swing the recording material P in the width direction X from time T13 to time T14. The CPU 301 turns on the light emitting element of the line sensor 25 from time T14 to time T15. The CPU 301 reads the amount of light received from time T14 to time T15 from the light receiving element of the line sensor 25 from time T15 to time T16.

  From time T16 to time T17, the CPU 301 determines the difference between the reference signal and the integration amount for each light receiving element. Then, the CPU 301 determines the amount of deviation of the recording material P in the width direction X using the difference. The integrated value is the sum of the light reception amount from time T0 to time T11 and the light reception amount from time T14 to time T15.

  In the example of FIG. 24, the light reception amount from the light receiving element is read twice (time T11 to T12, time T15 to T16). In addition, the recording material P is shaken between the two readings (time T13 to T14). As a result, it takes 77 ms to correct the amount of deviation.

  On the other hand, in the example of FIG. 8, the light receiving amount from the light receiving element is read out only once (time T1 to T2). The peristalsis of the recording material P is performed simultaneously with the reading. Thus, the time required to correct the amount of deviation is 61 ms. That is, as compared with the example of FIG. 24, the example of FIG. 8 shortens the time required to correct the amount of deviation of one recording material P by 16 ms.

  In the embodiment described above, the relative movement between the facing plate 200 and the recording material P is realized by the movement of the pair of registration rollers 26 sandwiching the recording material P. The image processing apparatus 100 includes a mechanism (for example, a motor) for moving the opposing plate 200, and the recording material P is relative to the opposing plate 200 by moving the opposing plate 200 in the width direction X by the mechanism. You may move it.

  When the position of the end portion of the recording material P is determined, if the position deviates from the ideal position, the CPU 301 further moves the resist roller pair 26 to eliminate the positional deviation of the recording material P. (Time T3 to time T4 etc. in FIG. 8). The CPU 301 may eliminate the deviation by shifting the position of the image formed on the recording material P. That is, after determining the position of the end portion of the recording material P, the CPU 301 calculates the amount of deviation of the position from the ideal position. Then, the CPU 301 corrects the image data of the recording material P so that the print position of the image cancels the shift amount, in order to eliminate the calculated shift amount. As a result, an image is formed on the recording material P having a positional deviation at a position adapted to the positional deviation.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In addition, the invention described in the embodiment and each modification is intended to be implemented as much as possible, alone or in combination.

  1P image output unit, 4 reader unit, 5 operation unit, 10 image forming unit, 21 sheet feeding cassette, 22 pickup roller pair, 23 conveyance roller pair, 24 conveyance guide, 25 line sensor, 26 registration roller pair, 27, 42 front Roller pair, 28 sheet sensor, 29a conveyance sensor, 29b prism, 30 intermediate transfer portion, 31 intermediate transfer belt, 32 drive roller, 33 tension roller, 34, 36 secondary transfer roller, 35a, 35d primary transfer roller, 40 fixing portion , 80 control unit, 100 image processing apparatus, 200 counter plate, 201, 203 black line, 202, 204 white line, 302 line sensor control unit, 303 analog processor, 305 registration drive motor, 306 shift motor, 307 front drive mode Chromatography, 308 opening and closing motor, 309 converter, 310 a comparator, 311 a counter, 314 size sensor, 320 memory unit, 330 a motor control unit.

Claims (11)

A transport path of the recording medium,
A sensor disposed to face at least a portion of the recording medium on the transport path;
An opposing plate disposed to face the sensor across the recording medium on the transport path;
A driving unit configured to relatively move the recording medium on the transport path and the counter plate in a first direction intersecting the transport direction on the transport path;
The opposing plate includes a plurality of color lines,
The sensor detects the amount of light reflected from the opposing plate side,
The plurality of color lines are arranged adjacent to each other in the first direction,
The driving means relatively moves the recording medium on the transport path and the opposing plate in the first direction in a predetermined period.
An image processing apparatus, further comprising: a processor configured to determine a position of an end of the recording medium on the transport path in the first direction using a detection output of the sensor corresponding to the predetermined period. . The sensor is
A light emitting element configured to emit light toward the recording medium on the transport path for the predetermined period;
A plurality of light receiving elements configured to receive light emitted by the light emitting elements, and arranged to be adjacent in a direction intersecting the transport direction;
The image processing apparatus according to claim 1, wherein the processor is configured to use, as the detection output, an integrated value of light reception amounts of the plurality of light receiving elements in the period. Each of the plurality of color lines has a predetermined length in the first direction,
3. The apparatus according to claim 1, wherein the driving means is configured to relatively move the recording medium on the transport path and the opposing plate for the predetermined length or more during the predetermined period. The image processing apparatus according to claim 1. Each of the plurality of color lines has a predetermined length in the first direction,
The predetermined length is
An integer multiple of a pixel of the light receiving element of the sensor in the first direction, and
Longer than the length of foreign matter expected to adhere to the opposite plate,
The driving unit is configured to move the recording medium on the transport path and the opposing plate relative to each other by a predetermined multiple of the predetermined length in the predetermined period. The image processing apparatus according to any one of claims 1 to 3. The driving means includes a motor
The processor drives the motor to cancel the operation in the predetermined period after the predetermined period has elapsed, and further to ensure that the motor shaft of the motor and the gear are engaged. The image processing apparatus according to any one of claims 1 to 4, wherein the motor is driven. The plurality of color lines are composed of colored lines and white lines alternately arranged with each other,
Each of the plurality of color lines has a predetermined length in the first direction,
The processor is
A first detection output which is a detection output of the sensor when there is no recording medium between the sensor and the opposing plate, and a second detection output which is a detection output of the sensor corresponding to the predetermined period Using the result of comparison with
The processor is
When the second detection output changes with respect to the first detection output in a portion corresponding to the innermost position in the first direction of the coloring line, the second detection output is the second detection output. The position moved in the first direction by the distance of the relative movement from the outermost position changed with respect to the detected output of 1 is determined as the position of the end in the first direction with respect to the white recording medium And
In the outermost colored line in which the second detection output changes with respect to the first detection output, the innermost position where the second detection output changes in the predetermined period is a white recording medium Determined as the position of the end in the first direction for
When the second detection output changes relative to the first detection output in a portion corresponding to the innermost position in the first direction of the white line, the second detection output is the second detection output. The position of the end in the first direction with respect to the colored recording medium, the position moved in the first direction by the distance of the relative movement from the outermost position changed with respect to the detection output of 1. Decided as
In the outermost white line in which the second detection output changes with respect to the first detection output, the innermost position where the second detection output changes in the predetermined period is colored. Determined as the position of the end in the first direction with respect to the recording medium,
The image processing apparatus according to any one of claims 1 to 5, which is configured as follows. The image processing apparatus further includes an image processing unit that processes an image formed on the recording medium,
The image processing unit is configured to adjust the position in the first direction of the image formed on the recording medium based on the position of the end of the recording medium in the first direction. An image processing apparatus according to any one of claims 1 to 6.   The processor is configured to cause the driving means to adjust the position of the recording medium in the first direction based on the position of the end of the recording medium in the first direction. The image processing apparatus according to claim 6. It further comprises a registration roller for controlling the conveyance of the recording sheet on the conveyance path,
The driving means is
Moving the first recording medium in the first direction by moving the resist roller to one side of the first direction during the predetermined period with respect to the first recording medium;
The second recording medium is moved by moving the resist roller to the one side in the first direction during the predetermined period with respect to the second recording medium conveyed next to the first recording medium. The image processing apparatus according to claim 1, wherein the image processing apparatus is configured to move in the first direction. The processor is
Based on the detection output of the sensor, it is determined whether or not foreign matter is present on the transport path,
When it is determined that a foreign matter is present on the transport path, the recording medium and the opposing plate are moved relative to each other in the first direction by a size longer than the size of the foreign matter than in the absence of the foreign matter. ,
The image processing apparatus according to any one of claims 1 to 9, which is configured as follows. The processor is
When the foreign matter is located at the end of the line in the first direction, the size of the foreign matter is longer than that in the absence of the foreign matter, and the recording medium and the opposing plate are relatively moved. Let
When the foreign matter is not located at the end of the line in the first direction, the recording medium and the opposing plate are moved relative to each other by the same dimension as in the case where the foreign matter is absent.
The image processing apparatus according to claim 10, wherein the image processing apparatus is configured as follows.