JP2015150850A - Image formation control device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manage laser beam deviation.SOLUTION: An image formation device comprises: an image carrier on which an image is formed with a light beam; a scan part which scans the light beam reflected with a rotary polygon mirror in a second direction while driving the image carrier in a first direction to irradiate the image carrier with the light beam; a transfer part which transfers the image on the image carrier to a sheet; and a control part which controls light emission while controlling scanning, generates an image of a j-th adjustment pattern which repeats the presence and absence of light emission in the second direction with a j-th reflection surface of the rotary polygon mirror and an image of a k-th adjustment pattern which repeats the presence and absence of light emission in the second direction with a k-th reflection surface of the rotary polygon mirror at the same light emission timing in the second direction, obtains the characteristic curve of a light receiving signal level, the light receiving element pitch of a reading part, the number of light receiving elements of the reading part corresponding to one period of the characteristic curve, the number of repetition of the adjustment pattern corresponding to one period of the characteristic curve, the number of light receiving elements corresponding to the phase difference, and the phase difference between the characteristic curves of the j-th adjustment pattern and the k-th adjustment pattern obtained by reading the images of the j-th/k-th adjustment patterns, and calculates the positional deviation in the second direction of the images of the j-th/k-th adjustment patterns.

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and a control apparatus therefor, and more particularly to control of an image forming apparatus having a function of scanning a laser beam from a light source and writing it on a recording medium such as a photoconductor.

  As an image forming apparatus, one or more lines in a second direction (main scanning direction) corresponding to image data while driving an image carrier such as a photosensitive drum or a photosensitive belt in the first direction (sub-scanning direction) A device that performs two-dimensional (one page) image formation by repeatedly performing image formation for each image is known.

  As an example, in an electrophotographic image forming apparatus, a laser beam modulated according to image data is scanned in the main scanning direction, and at the same time, an image carrier (photosensitive drum or An image is formed on the photosensitive belt by the laser beam. In this case, the laser beam is modulated with image data on the basis of a clock signal (pixel clock) called a dot clock.

In order to realize such main scanning of the laser beam, a rotating polygon mirror having a plurality of rotating reflecting surfaces is used.
In this case, it is formed by a laser beam scanned on each surface of the rotating polygon mirror due to the influence of uneven rotation of the polygon motor driving the rotating polygon mirror and the difference in surface accuracy of each reflecting surface of the rotating polygon mirror. There arises a problem that the position of each pixel in the main scanning direction is shifted.

  Here, FIG. 12 schematically shows the deviation in the main scanning direction of each reflecting surface of the six-sided rotary polygon mirror. In this case, as shown in FIG. 12, the end in the main scanning direction formed on the image carrier by the reflecting surfaces # 1 to # 6 of the rotary polygon mirror is at a different position.

  In FIG. 13, the main scanning direction deviation of each reflecting surface of the same six-sided rotary polygon mirror as in FIG. 12 is converted into the vertical axis direction, and how the deviation state changes according to each position in the main scanning direction. It is explanatory drawing which shows such a profile typically. The characteristic of the inclination of the deviation state in FIG. 13 represents the difference in flatness of each reflecting surface. That is, as shown in FIG. 13, misregistration can occur at the intermediate positions in the main scanning direction with respect to the dots at the respective positions in the main scanning direction formed by the reflecting surfaces # 1 to # 6 of the rotary polygon mirror. Become.

  For example, in FIGS. 12 and 13, the first reflection surface (# 1) and the third reflection surface (# 3) of the rotary polygon mirror have substantially the same end deviation in the main scanning direction. However, the profiles in the middle of the main scanning direction are different. For this reason, when # 1 and # 3 are uniformly reduced, the pixel positions at the start and end of the main scanning direction are aligned, but the pixel positions are not aligned near the middle in the main scanning direction.

  FIG. 14 schematically shows a state in which an image is formed using image data for forming dots at equal intervals using the rotating polygon mirror as shown in FIG. Here, the pixel positions at the start and end of the main scanning direction are aligned.

  In this case, depending on the type of image, there may be a phenomenon that the image looks like moire or a vertical line (a line or dot arrangement in the sub-scanning direction orthogonal to the main scanning direction) is distorted. In addition, there may be a difference in shading that a group of dots closer to the original looks darker and a group of dots more discrete than the original looks thinner.

  Various adjustments in the case of forming an image by scanning with a laser beam are described in Patent Document 1 below.

JP 2002-182139 A JP 2005-208323 A

  In each of the above patent documents, it is proposed that sensors are provided on the start side and the end side outside the image area, the length in the main scanning direction is obtained from the passage timing of the laser beam, and the length in the main scanning direction is corrected. . In this case, the start and end positions can be aligned, but the alignment cannot be performed at the intermediate portion. In addition, when a paper smaller than the image carrier is used, even the start and end of the actual image do not match.

  It has also been proposed to measure and correct dot position deviations not only at the start and end points but also at the intermediate part by using a dedicated jig at the manufacturing stage. However, it cannot be dealt with when the measurement is troublesome, the problem that the displacement cannot be completely eliminated due to the difference in position between the measurement jig and the actual image carrier, or when the customer replaces the rotating polygon mirror during use. Various problems such as problems exist.

  The present invention has been made to solve the above-described problems, and realizes an image forming control apparatus and an image forming apparatus capable of appropriately managing a positional deviation of a laser beam scanned by a rotating polygon mirror. The purpose is to do.

  (1) In one aspect of the image forming control apparatus and the image forming apparatus reflecting one aspect of the present invention, the light beam scanned in the second direction orthogonal to the first direction while being driven in the first direction. An image carrier that forms an image on the surface by receiving the light, a light emitting unit that generates the light beam, a first scanning unit that drives the image carrier in the first direction, and a plurality of polygons included in the rotary polygon mirror A second scanning unit that irradiates the image carrier while scanning the light beam in the second direction by reflecting the light beam on the reflection surface, and an image formed by irradiating the light beam on the image carrier And controlling the scanning of the first scanning unit and the scanning of the second scanning unit when controlling an image forming apparatus having a transfer unit that converts the visible image onto a sheet. A control unit for controlling the light emission timing of the light emitting unit, The control unit uses the jth reflective surface when any of the reflective surfaces included in the rotary polygon mirror is the jth reflective surface and any of the reflective surfaces different from the jth reflective surface is the kth reflective surface. An image of a jth adjustment pattern that alternately repeats light emission and no light emission in the second direction, and an image of a kth adjustment pattern that alternately repeats light emission and light emission in the second direction by the kth reflection surface. The characteristic curve of the received light signal level obtained by controlling the light emitting unit to generate the same light emission timing in the second direction and reading the image of the jth adjustment pattern and the image of the kth adjustment pattern by the reading unit. , The light receiving element pitch of the reading unit, the number of light receiving elements in the reading unit corresponding to one period of the characteristic curve, the number of repetitions of the adjustment pattern corresponding to one period of the characteristic curve, and the light receiving element corresponding to the phase difference Number, said obtaining a phase difference between characteristic curves of the j adjustment pattern and the kth adjustment pattern, and calculating a positional deviation in the second direction between the image of the jth adjustment pattern and the image of the kth adjustment pattern. Features.

  (2) In the above (1), the control unit controls to generate the jth adjustment pattern and the kth adjustment pattern at least on the scanning end side in the second direction.

  (3) In the above (1) to (2), the control unit controls to generate the jth adjustment pattern and the kth adjustment pattern in correspondence with each other in a plurality of regions in the second direction. It is characterized by that.

  (4) In the above (1) to (3), the control unit includes at least one of the scanning start end side and the scanning end side in the second direction of the paper to be used as the plurality of regions in the second direction. As described above, control is performed such that the jth adjustment pattern and the kth adjustment pattern are generated in correspondence with each other.

  (5) In the above (1) to (4), the control unit controls the light emitting unit so as to generate an image of an adjustment pattern that alternately repeats the presence of light emission and the absence of light emission in the second direction, and When the pitch of the light receiving elements included in the reading unit is controlled to be p, and the pitch between the presence and absence of light emission in the adjustment pattern is p + δp, where δp <p, this corresponds to one period of the characteristic curve. The number of light receiving elements in the reading unit is determined as X ′, the number of repetitions of the adjustment pattern corresponding to one period of the characteristic curve is determined as X, and the number of light receiving elements corresponding to the phase difference is determined as Y. The deviation Z is calculated as Z = (((X′−X) · Y) / X) p.

  (6) In the above (1) to (5), the characteristic curve includes an odd characteristic curve connecting light reception signal values of odd-numbered light receiving elements and an even characteristic curve connecting light reception signal values of even-numbered light receiving elements. It is characterized by.

  (7) In the above (1) to (6), when the number of reflecting surfaces included in the rotary polygon mirror is M, the control unit performs the first direction of the image carrier by the first scanning unit. Is changed to 1 / M of the normal time, and the image of the j-th adjustment pattern and the image of the k-th adjustment pattern are each generated repeatedly in the first direction as a continuous state. It is characterized by that.

  (8) In the above (1) to (7), the control unit performs control so as to generate the jth adjustment pattern and the kth adjustment pattern corresponding to one period of the characteristic curve in the second direction. It is characterized by that.

(9) In the above (1) to (8), the control unit adjusts the light emission timing of the light emitting unit for each reflection surface so as to eliminate the calculated positional deviation. .
(10) In the above (1) to (9), the control unit calculates the positional deviation for each of the adjacent reflecting surfaces included in the rotary polygon mirror, and calculates the position for each of the adjacent reflecting surfaces. The light emission timing of the light emitting unit for each of the reflection surfaces is adjusted so as to eliminate the positional deviation.

  (11) In the image forming apparatus according to (1) to (10), the image forming apparatus includes a reading unit that reads an image of the jth adjustment pattern and an image of the kth adjustment pattern.

  (1) In one aspect of the image forming control apparatus and the image forming apparatus in which one aspect of the present invention is reflected, first, any of the reflecting surfaces included in the rotary polygon mirror is different from the jth reflecting surface and the jth reflecting surface. When any one of the reflection surfaces is the kth reflection surface, an image of the jth adjustment pattern that alternately repeats light emission and no light emission in the second direction by the jth reflection surface, and the second direction by the kth reflection surface. The light emitting unit is controlled so as to generate an image of the kth adjustment pattern that alternately repeats light emission and no light emission at the same light emission timing in the second direction. Then, from the light receiving signal obtained by reading the image of the jth adjustment pattern and the image of the kth adjustment pattern by the reading unit, the reading corresponding to the characteristic curve of the light receiving signal level, the light receiving element pitch of the reading unit, and one cycle of the characteristic curve. Obtaining the number of light receiving elements in the unit, the number of repetitions of the adjustment pattern corresponding to one period of the characteristic curve, the number of light receiving elements corresponding to the phase difference, and the phase difference between the characteristic curves of the jth adjustment pattern and the kth adjustment pattern, From these, the displacement in the second direction between the image of the jth adjustment pattern and the image of the kth adjustment pattern is calculated.

  The positional deviation in the second direction between the jth adjustment pattern and the kth adjustment pattern calculated in this way corresponds to the positional deviation of the laser beam scanned by the rotary polygon mirror. Accordingly, it is possible to appropriately manage the positional deviation of the laser beam scanned by the rotary polygon mirror.

  (2) In the above (1), by generating the j-th adjustment pattern and the k-th adjustment pattern at least on the scanning end side in the second direction, the positional deviation of the laser beam scanned by the rotary polygon mirror is at least It is possible to appropriately manage at the position on the end side in the main scanning direction.

  (3) In the above (1) to (2), the j-th adjustment pattern and the k-th adjustment pattern are generated in correspondence with each other in the plurality of regions in the second direction, so that the laser beam scanned by the rotary polygon mirror Can be properly managed at a plurality of positions in the main scanning direction.

  (4) In the above (1) to (3), the j-th adjustment pattern is such that the plurality of regions in the second direction include at least one of the scanning start end side and the scanning end side in the second direction of the paper to be used. And the k-th adjustment pattern are generated in correspondence with each other so that the positional deviation of the laser beam scanned by the rotary polygon mirror is at least one of the scanning start side and the scanning end side in the main scanning direction of the paper to be used. Can be managed appropriately. That is, it is possible to appropriately manage the positional deviation of the laser beam scanned by the rotary polygon mirror at at least one position on the scanning start end side or scanning end side of the actually used paper.

  (5) In the above (1) to (4), the pitch of the light receiving elements included in the reading unit is set to p, and the pitch between the presence and absence of light emission in the adjustment pattern is p + δp, where δp <p. In this case, the number of light receiving elements in the reading unit corresponding to one period of the characteristic curve is X ′, the number of adjustment pattern repetitions corresponding to one period of the characteristic curve is X, and the number of light receiving elements corresponding to the phase difference is Y. The positional deviation Z in the second direction is calculated as Z = (((X′−X) · Y) / X) p. As a result, the positional deviation of the laser beam scanned by the rotating polygon mirror can be accurately calculated by calculation, and can be appropriately grasped.

  (6) In the above (1) to (5), the characteristic curve is composed of an odd characteristic curve connecting light reception signal values of odd-numbered light receiving elements and an even characteristic curve connecting light reception signal values of even-numbered light receiving elements. Therefore, it is possible to easily detect the period and phase difference of the characteristic curve.

  (7) In the above (1) to (6), when the number of reflecting surfaces included in the rotary polygon mirror is M, the driving speed in the first direction of the image carrier by the first scanning unit is set to 1 / of the normal time. By changing to M and controlling the image of the jth adjustment pattern and the image of the kth adjustment pattern to be generated as a continuous state repeated a plurality of times in the first direction, the adjustment pattern is a line that is continuous in the first direction. Thus, reading by the reading unit is facilitated.

  (8) In the above (1) to (7), scanning is performed by the rotary polygon mirror by controlling to generate the jth adjustment pattern and the kth adjustment pattern corresponding to one period of the characteristic curve in the second direction. Therefore, it is possible to accurately calculate the position deviation of the laser beam with no waste by calculation, and to grasp it appropriately.

  (9) In (1) to (8) above, the light emission timing of the light emitting unit for each reflecting surface is adjusted so as to eliminate the calculated positional deviation. As a result, the positional deviation of the laser beam scanned by the rotating polygon mirror can be accurately eliminated by calculation. Further, since the light emission timing is adjusted based on the calculated positional deviation, it is not necessary to repeat the fine adjustment a plurality of times, and appropriate adjustment can be performed simply.

  (10) In the above (1) to (9), the reflection surface is calculated so that the positional deviation is calculated for each adjacent reflection surface included in the rotary polygon mirror, and the positional deviation calculated for each adjacent reflection surface is eliminated. The light emission timing of each light emitting unit is adjusted. As a result, the positional deviation between the adjacent reflecting surfaces of the laser beam scanned by the rotating polygon mirror can be accurately eliminated by calculation.

  (11) In the image forming apparatus according to (1) to (10), the position of the laser beam scanned by the rotary polygon mirror is provided by including a reading unit that reads the image of the jth adjustment pattern and the image of the kth adjustment pattern. The deviation can be accurately read and eliminated by calculation.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. It is explanatory drawing of the adjustment pattern used by one Embodiment of this invention. It is explanatory drawing of the adjustment pattern used by one Embodiment of this invention. It is explanatory drawing of the adjustment pattern used by one Embodiment of this invention. It is explanatory drawing of the adjustment pattern used by one Embodiment of this invention. 6 is a flowchart illustrating an operation of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows operation | movement of the image forming apparatus of one Embodiment of this invention. It is explanatory drawing which shows operation | movement of the image forming apparatus of one Embodiment of this invention. It is explanatory drawing which shows operation | movement of the image forming apparatus of one Embodiment of this invention. It is explanatory drawing which shows the mode of the dot position shift by each reflective surface of a rotary polygon mirror. It is explanatory drawing which shows the mode of the dot position shift by each reflective surface of a rotary polygon mirror. It is explanatory drawing which shows the mode of the dot position shift by each reflective surface of a rotary polygon mirror.

The best mode (embodiment) for carrying out the present invention will be described below in detail with reference to the drawings.
[First configuration]
Hereinafter, the configuration of the image forming apparatus 100 according to the present exemplary embodiment will be described in detail with reference to FIGS. 1 and 2. 1 is a block diagram showing the overall configuration of the image forming apparatus 100, and FIG. 2 is a perspective view showing the vicinity of the optical system 170. Note that constituent elements that are common as the image forming apparatus 100 and are well-known are omitted.

  An image forming apparatus 100 shown in FIG. 1 is composed of a CPU or the like for controlling each part of the image forming apparatus 100, and an overall control unit 101 that controls laser emission according to image data or predetermined command data. The storage unit 103 as a storage unit for storing various parameters such as various programs such as an image forming program and an adjustment program and adjustment pattern data, and an operation input signal corresponding to the operation input by the operator to the overall control unit 101 An operation unit 105 serving as an operation display unit for notifying and displaying various information according to instructions from the overall control unit 101, a reading unit 110 serving as a reading unit for reading an image of a document and generating image data, and an overall control unit Based on an instruction from 101, image data input from the outside or generated by reading by the reading unit 110 An image processing unit 120 that performs image processing necessary for image formation on the image data, a laser control unit 130 that controls light emission driving of the light source according to the image data based on the control of the overall control unit 101, and image formation A print engine 140 as an image forming unit to be performed, a print head 150 that emits and scans a laser beam in the print engine 140, a laser drive circuit 160 that drives a laser diode as a light source, and a laser beam from the laser diode And an optical system 170 composed of optical components for scanning the photosensitive member, and a process unit 180 that receives a laser beam scan from the print head 150 to form a toner image. .

  In addition, when an image of an adjustment pattern that repeats light emission and light emission alternately in the main scanning direction is formed by the print engine 140, rotation is performed from adjustment pattern image data obtained by reading a predetermined adjustment pattern by the reading unit 110. A light emission positional deviation control unit 190 that calculates the positional deviation of the laser beam reflected by each surface of the polygon mirror is configured. Here, the overall control unit 101, the laser control unit 130, and the light emission position deviation control unit 190 can be combined and handled as a control unit.

  1 illustrates a state in which the reading unit 110 and the light emission position deviation control unit 190 are included in the image forming apparatus 100, the present invention is not limited to this. For example, the reading unit 110 may be a sensor that reads an adjustment pattern on an image carrier or a sheet after transfer, in addition to the reading unit 110 that reads an original in the image forming apparatus 100, or may be a sensor external to the image forming apparatus 100. It may be a scanner.

  In the adjustment mode of the image forming apparatus 100, the light emission position deviation control unit 190 generates an image of an adjustment pattern that alternately repeats light emission and light emission in the main scanning direction when controlling the light emission timing of the light emission unit. As described above, the laser controller 130 and the print engine 140 are controlled in accordance with each reflection surface of the rotary polygon mirror based on the laser beam positional deviation calculated by the light emission positional deviation control unit 190 from the read result of the image of the adjustment pattern. And control to determine the light emission timing of the light emitting unit.

  In FIG. 2, an optical system 170 included in the print head 150 includes a laser diode 171 as a light source including a light emitting unit, a collimator lens 172 and a cylindrical lens 173 for optically correcting various laser beams, and a laser beam as a main component. A rotating polygon mirror 174 that scans in the scanning direction, an fθ lens 175 that optically corrects a scanning angle, a cylindrical lens 176 that optically corrects, a mirror 177 for detecting a horizontal synchronizing signal, and a mirror 177 for detecting a horizontal synchronizing signal And a horizontal synchronization sensor 178.

  Then, on the photosensitive drum 181 as an image carrier, the photosensitive drum 181 is rotated as scanning in the sub-scanning direction (first direction), and the direction parallel to the central axis of the cylindrical photosensitive drum 181 is mainly set. When the laser beam scans in the scanning direction (second direction), a latent image corresponding to the laser beam is formed on the surface of the photosensitive drum 181.

  2 may be configured to generate a plurality of laser beams in the sub-scanning direction (first direction) orthogonal to the main scanning direction (second direction). It may be configured to generate a single laser beam. In the case of a plurality of laser beams, a state where four lines of laser beams are generated is shown, but the present invention is not limited to the illustrated four lines.

  In the above configuration, when performing parallel exposure with the laser diode 171 having a plurality of light emitting units, the image processing unit 120 outputs image data for each line in parallel, or the laser control unit 130 The image data for a plurality of lines may be accumulated and the laser diode 171 may be driven in parallel for the plurality of lines.

[Second configuration]
Hereinafter, the relationship between the image forming control apparatus 300 and the image forming apparatus 100 of the present embodiment is shown in FIG. In the image forming apparatus 100, the same components as those in FIG.

  This image formation control device 300 is a function of the light emission position deviation control unit 190 included in the image forming apparatus 100 of FIG. 1 (based on each reflection surface of the rotary polygon mirror based on the calculated position deviation of the laser beam). A function of controlling to determine the light emission timing). Regarding the reading of the adjustment pattern, the reading unit 110 in the image forming apparatus 100 or the external reading apparatus 200 may be used.

  Note that the image forming apparatus 100, the reading apparatus 200, and the image forming control apparatus 300 are connected via the network 10. The network 10 may be various networks, or may be a simple wired or wireless direct connection.

[Adjustment pattern layout]
Hereinafter, a basic portion of the adjustment pattern controlled by the image forming apparatus 100 and the image forming control apparatus 300 according to the present embodiment will be described with reference to FIG.

  Here, the overall control unit 101, the laser control unit 130, and the light emission position deviation control unit 190 are configured so that any one of the reflection surfaces included in the rotary polygon mirror 174 is different from the jth reflection surface and the jth reflection surface. Is the kth reflection surface, and the jth adjustment surface repeats light emission with and without light emission in the main scanning direction by the jth reflection surface, and light emission with and without light emission in the main scanning direction by the kth reflection surface. Each unit is controlled so that an image of the kth adjustment pattern that alternately repeats nothing is generated at the same light emission timing in the main scanning direction.

Here, the case where the rotary polygon mirror 174 has six surfaces is taken as a specific example, but the number of other surfaces may be used, and the total number of reflection surfaces is M.
Therefore, in practice, if the number M of reflection surfaces is 6, the first adjustment pattern generated using only the first reflection surface of the rotary polygon mirror 174 and the second adjustment pattern generated using only the second reflection surface. A third adjustment pattern generated using only the third reflection surface, a fourth adjustment pattern generated using only the fourth reflection surface, a fifth adjustment pattern generated using only the fifth reflection surface, and a sixth reflection surface Each unit is controlled so that the image of the sixth adjustment pattern generated using only the same is generated at the same light emission timing in the main scanning direction.

  FIG. 4 shows either the state where the surface of the photosensitive drum 181 on which the adjustment pattern is formed is developed or the state where the adjustment pattern is transferred from the photosensitive drum 181 to a sheet.

  Here, for this adjustment pattern, the j-th adjustment pattern and the k-th adjustment pattern are generated at the same emission timing in the main scanning direction at least on the scanning end side in the main scanning direction (second direction). It is desirable to control such that This is to eliminate the accumulated positional deviation (see FIG. 12) on the end side in the main scanning direction.

  In the example of FIG. 4, the first adjustment pattern (Pt # 1R) formed on the end side in the main scanning direction (right side in the main scanning direction in FIG. 4) using only the first reflecting surface, the second reflecting surface. A second adjustment pattern (Pt # 2R) formed on the end side in the main scanning direction using only the third adjustment pattern (Pt # 3R) formed on the end side in the main scanning direction using only the third reflecting surface, A fourth adjustment pattern (Pt # 4R) formed on the end side in the main scanning direction using only the fourth reflecting surface, and a fifth adjustment pattern (Pt) formed on the end side in the main scanning direction using only the fifth reflecting surface. # 5R), a sixth adjustment pattern (Pt # 6R) formed on the end side in the main scanning direction using only the sixth reflecting surface.

  In addition, it is desirable to perform control so that the jth adjustment pattern and the kth adjustment pattern are generated in correspondence with each other in a plurality of regions in the main scanning direction. This is to eliminate misalignment (see FIGS. 13 and 14) occurring at each position in the main scanning direction.

  In the example of FIG. 5, the first adjustment pattern (Pt # 1L) formed on the start side in the main scanning direction (left side in the main scanning direction in FIG. 5) using only the first to sixth reflecting surfaces. To a sixth adjustment pattern (Pt # 6L), and a first adjustment pattern (center side in the main scanning direction in FIG. 5) formed using only the first reflection surface to the sixth reflection surface. Pt # 1C) to the sixth adjustment pattern (Pt # 6C) and only the first reflection surface to the sixth reflection surface are used to form the terminal side in the main scanning direction (the right side in the main scanning direction in FIG. 5). The first adjustment pattern (Pt # 1R) to the sixth adjustment pattern (Pt # 6R) are shown.

  In FIG. 5, the adjustment pattern is formed in the three regions on the start side, the center, and the end side in the main scanning direction, but the present invention is not limited to this. In other words, the adjustment pattern may be provided in five regions in the main scanning direction: the start end, the middle between the start end and the center, the center, the middle between the center and the end, and the end. Further, any of two regions, four regions, six regions or more in the main scanning direction may be used.

  In addition, with respect to this adjustment pattern, the j-th adjustment pattern and the k-th adjustment pattern are defined as a plurality of regions in the main scanning direction of at least the paper size actually used or in the main scanning direction of the paper size actually used. It is desirable to control so that these are generated in correspondence with each other. This is to eliminate the positional deviation that occurs at each position in the main scanning direction in the paper size that is actually used regardless of the size of the photosensitive drum 181. This is particularly effective when a sheet having a size smaller than the size of the photosensitive drum 181 is used.

  In the above case, if the paper is the minimum size, an adjustment pattern is generated on the end side in the main scanning direction of the paper size. If the paper is a medium size, the adjustment pattern is generated on the start side and the end side of the paper size. It is also desirable to generate an adjustment pattern and generate a variable number of adjustment patterns, such as generating an adjustment pattern on the start side, center, and end side of the paper size for the largest size paper.

[Details of adjustment pattern]
FIG. 6 is an enlarged view of a start portion of the adjustment pattern in the main scanning direction, and FIG. 7 shows an entire area having about one cycle in the main scanning direction of the adjustment pattern. Here, as described above, the sub-scanning direction in image formation is defined as the first direction, and the main scanning direction is defined as the second direction.

  FIG. 6A shows a state in which an image of an adjustment pattern that alternately repeats light emission and light emission alternately in the main scanning direction is formed in the sub-scanning direction. That is, an adjustment pattern is formed in which black lines and blank lines with the sub-scanning direction as the longitudinal direction are alternately repeated in the main scanning direction.

  In the printing field, a black line and a blank line are generally handled as one pair, and the number of black line lines (line pairs) is generally counted. However, in this embodiment, considering the correspondence between the vertical line formed by the adjustment pattern and the element number of the light receiving element, the black line (black line) and the blank line (white line) are counted as two lines. An explanation will be given with an example of calculation by a method according to so-called TV resolution.

  In addition, when counting with a line pair in which a black line and a blank line are one pair, the number of lines in the description to be described later may be halved, so that the processing contents and calculation results change fundamentally. There is no change in the effect obtained.

  Here, the adjustment pattern in FIG. 6A is read by the reading unit 110 in FIG. In the state of FIG. 6, the light receiving elements included in the reading unit 110 are numbered # 1 to # 14. Then, the pitch of the light receiving elements included in the reading unit 110 (adjacent light receiving element spacing) is controlled to be p, and the pitch between the presence and absence of light emission in the adjustment pattern is p + δp, where δp <p.

  In addition, when the pitch p1 of the adjustment pattern generated by repeating the presence of light emission and the absence of light emission with one dot is significantly smaller than the light receiving element pitch p, and does not satisfy the relationship between p and p + δp described above, The overall control unit 101, the laser control unit 130, and the light emission position deviation control unit 190 control such that a plurality of dots are emitted in the main scanning direction and a plurality of dots are not emitted in the main scanning direction.

  When the light receiving element # 1 is positioned so that the black line of the adjustment pattern coincides with the light receiving element # 1, the light receiving element # 1 reads the black line, so that the light receiving signal value becomes a minimum value near zero. Since the black line is gradually shifted from the odd-numbered light receiving element # 3 and the light receiving element # 5 due to the difference between the adjustment pattern pitch p + δp and the light receiving element pitch p, the light receiving signal gradually enters. The value increases (FIG. 6 (c)). When the odd-numbered light reception signal values are connected, a smooth characteristic curve (odd characteristic curve) is obtained.

  On the other hand, the light receiving element # 2 is in a state matching the blank line of the adjustment pattern, and the light receiving element # 2 reads the blank line, so that the received light signal value is near the maximum value. Then, due to the difference between the adjustment pattern pitch p + δp and the light receiving element pitch p, the black lines gradually enter the even-numbered light receiving elements # 4 and # 6 and the blank lines. The value decreases (FIG. 6 (c)). When the even-numbered light receiving signal values are connected, a smooth characteristic curve (even characteristic curve) is obtained.

In the present embodiment, the “characteristic curve” means a curve generated by connecting either odd-numbered or even-numbered signal values.
In addition, the phenomenon in which the positional relationship between the adjustment pattern and the light receiving element gradually shifts in this way is similar to the principle of “moire” that occurs when shades of different pitches overlap.

When the characteristics of the adjustment pattern, the light receiving element, and the light receiving signal value shown in FIG. 6 are further extended in the main scanning direction, the state shown in FIG. 7 is obtained.
In FIG. 7, it can be read that the light receiving element # 1 and the light receiving element # 43 are in a state in which the black line coincides with the position of the light receiving element (light receiving signal value = lowest). That is, it can be seen that 40 lines (40 (p + δp)) of black lines and blank lines in the adjustment pattern coincide with 42 light receiving elements (42p) as one period λ of the characteristic curve.

  In this case, since 40 (p + δp) = 42p, δp = 0.05p. That is, with respect to the light receiving element pitch p, the pitch (p + δp) between the presence and absence of light emission in the adjustment pattern is found to be 1.05p.

  Even if the light receiving element # 1 and the black line of the adjustment pattern do not coincide with each other, the odd characteristic curve and the even characteristic curve described above result in a state at any position included in FIG. Only the phase in the main scanning direction is shifted, and no problem occurs.

  4 and FIG. 5, as shown in FIG. 7 described above, the overall control unit 101 is set so that an adjustment pattern corresponding to one period of the characteristic curve is generated in the main scanning direction. It is desirable that the laser control unit 130 and the light emission position deviation control unit 190 perform control.

[Operation of Embodiment]
The operation of the image forming apparatus 100 of the present embodiment or the image forming control apparatus 300 of the present embodiment will be described below with reference to the flowchart of FIG. 8 and the adjustment pattern reading state explanatory diagrams of FIGS. 9 to 11.

In the following description, the operation of the image forming apparatus 100 will be mainly described, and a duplicate description when the image forming control apparatus 300 executes similar control will be omitted.
The overall control unit 101 monitors the state of the image forming apparatus 100, an input from the operation unit 105, an instruction from an external device (not shown), and the like, and determines an operation mode of the image forming apparatus 100 based on these. When an adjustment instruction is input, the overall control unit 101 causes the image forming apparatus 100 to operate in the adjustment mode.

In this adjustment mode, the overall control unit 101 delegates the authority to control each unit of the image forming apparatus 100 to the light emission position deviation control unit 190.
In this adjustment mode, the light emission position deviation control unit 190 controls the sub-scanning direction speed, that is, the rotational speed of the photosensitive drum 181 and the paper transport speed to be 1 / M during normal image formation. M is the number of reflecting surfaces of the rotary polygon mirror 174. Here, since the rotary polygon mirror 174 having 6 reflecting surfaces is used, the sub-scanning direction speed is controlled to 1/6 of the normal time (step S101 in FIG. 8).

Then, the light emission position deviation control unit 190 sets the initial value to 1 for the variable i that defines the i-th reflection surface and the i-th adjustment pattern (step S102 in FIG. 8).
Here, the light emission position deviation control unit 190 reflects the laser beam from the laser diode 171 using only the first reflection surface, and has a first adjustment pattern that repeats light emission and light emission alternately in the main scanning direction. The laser controller 130 and the print head 150 are driven and controlled so that an image is repeatedly generated by a predetermined number of lines in the sub-scanning direction (step S103 in FIG. 8).

  Then, the light emission position deviation control unit 190 sets i = i + 1 for the variable i (step S104 in FIG. 8), until the set i reaches M (NO in step S105 in FIG. 8). The laser control unit 130 and the print head 150 are driven and controlled so that an image of the i-th adjustment pattern using only the reflective surface is repeatedly generated by a predetermined number of lines in the sub-scanning direction (step S103 in FIG. 8). .

  That is, the control of the light emission position deviation control unit 190 controls the drive of the laser control unit 130 and the print head 150 so as to generate the first adjustment pattern to the sixth adjustment pattern (steps S103 to S105 in FIG. 8). .

  Note that, as illustrated in FIGS. 4 and 5, the light emission position deviation control unit 190 performs control so that the first adjustment pattern to the sixth adjustment pattern are generated in association with each other in at least one region in the main scanning direction.

Then, the reading unit 110 reads the adjustment pattern corresponding to each reflection surface formed as described above based on an instruction from the light emission position deviation control unit 190 (step S106 in FIG. 8).
The reading unit 110 reads the toner image on the surface of the photosensitive drum 181, reads the paper transferred from the photosensitive drum 181 (during conveyance), and reads the paper output from the image forming apparatus 100. Reading in a state of being set in the section may be performed.
Further, the light emission position deviation control unit 190 can use the result of receiving the result of reading the paper by the reading device 200.

  Reading of the adjustment pattern formed in this way and detection of deviation will be described with reference to FIGS. FIG. 9 is an enlarged view of the portion (starting portion) of FIG. FIG. 11 is an explanatory diagram in which explanations are added to the respective regions in FIG.

  9 to 10, (a1) shows a first adjustment pattern in which the laser diode 171 is controlled so as to alternately repeat light emission and no light emission. Note that a state in which the image of the first adjustment pattern is repeated for a predetermined line in the sub-scanning direction is shown. Here, since the light emission position deviation control unit 190 sets the sub-scanning direction speed to 1 / (the number of reflecting surfaces of the rotary polygon mirror 174), the adjustment pattern (black line, blank line) is a continuous line in the sub-scanning direction. Thus, reading by the reading unit 110 is facilitated.

  9 to 10, (a2) shows a second adjustment pattern in which the laser diode 171 is controlled to alternately repeat light emission and no light emission at the same timing as (a1) described above in the main scanning direction. Yes. Similarly, a state in which the image of the second adjustment pattern is repeated for a predetermined line in the sub-scanning direction is shown. Here, since the light emission position deviation control unit 190 sets the sub-scanning direction speed to 1 / (the number of reflecting surfaces of the rotary polygon mirror 174), the adjustment pattern (black line, blank line) is a continuous line in the sub-scanning direction. Thus, reading by the reading unit 110 is facilitated.

  As already described, the reflecting surfaces of the rotary polygon mirror 174 are not completely uniform. For this reason, it is assumed that the first adjustment pattern and the second adjustment pattern have a Z misalignment in the main scanning direction as shown in FIG.

  9 to 10, the light emission position deviation control unit 190 is obtained from the results obtained by reading (a1) and (a2) with the reading unit 110 in the same manner as described with reference to FIGS. 6 and 7. An odd characteristic curve based on the light reception signal value of the odd number light receiving element and an even characteristic curve based on the light reception signal value of the even number light receiving element are created.

  9C to 10C, the thin solid line is the characteristic curve “first odd characteristic curve” of the odd-numbered received light signal value obtained by reading the first adjustment pattern (a1), and the thick solid line is the first solid line. A characteristic curve “first even characteristic curve” of even-numbered light reception signal values obtained by reading one adjustment pattern (a1), and a thin broken line indicates odd-numbered light reception signal values obtained by reading the second adjustment pattern (a2). The characteristic curve is the “second odd characteristic curve”, and the thick broken line is the characteristic curve “second even characteristic curve” of the even-numbered received light signal value obtained by reading the second adjustment pattern (a2).

  In addition, the “first odd characteristic curve” and the “first even characteristic curve” related to the first adjustment pattern are collectively referred to as “first characteristic curve”, and the “second odd characteristic” related to the second adjustment pattern. The “curve” and the “second even characteristic curve” are collectively referred to as a “second characteristic curve”. Further, the “first characteristic curve” and the “second characteristic curve” are collectively referred to as “characteristic curve”. Note that the i-th characteristic curve, the i-th odd-number characteristic curve, and the i-th even-number characteristic curve may be read as necessary in relation to the i-th adjustment pattern corresponding to the i-th reflection surface.

  Then, the light emission position deviation control unit 190 detects how many lines of the adjustment pattern correspond to one line λ of the characteristic curve period and how many elements of the light receiving element correspond to the above characteristic curve. Similarly, the light emission position deviation control unit 190 detects how many light receiving elements the phase difference Pdif between the first characteristic curve and the second characteristic curve corresponds to from the above characteristic curves (step in FIG. 8). S107). This detection is realized by image processing inside the light emitting element position deviation control unit 190.

  In FIG. 10, in the first odd-number characteristic curve, it can be seen that the light receiving element # 1 and the light receiving element # 43 are in a state where the black line coincides with the position of the light receiving element (light receiving signal value = lowest). That is, it can be seen that 40 lines (40 (p + δp)) of black lines and blank lines in the adjustment pattern coincide with 42 light receiving elements (42p) as one period λ of the characteristic curve.

  Here, let X be the number of adjustment pattern lines corresponding to one cycle λ of the characteristic curve (= the number of adjustment pattern repetitions, hereinafter “number of one cycle line”). In the specific example of this embodiment, X = 40.

  Further, the number of light receiving elements corresponding to one cycle λ of the characteristic curve (hereinafter, “the number of light receiving elements per cycle”) is assumed to be X ′. In the specific example of this embodiment, X ′ = 42. Further, X′−X = δx, where δx = 2. Note that X is a value inversely proportional to the difference δp between the light receiving element pitch and the adjustment pattern pitch.

  Further, in FIG. 10, the intersection of the first odd characteristic curve and the first even characteristic curve (hereinafter referred to as the first intersection) and the intersection of the second odd characteristic curve and the second even characteristic curve, the first intersection point. It can be read that the phase difference Pdif from the intersection of the same phase (hereinafter referred to as the second intersection) is 8 light receiving elements (8p).

  The phase difference from the maximum value (or minimum value) of the first odd characteristic curve (or first even characteristic curve) and the maximum value (or minimum value) of the second odd characteristic curve (or second even characteristic curve). Pdif can also be obtained. Here, the number of light receiving elements (number of characteristic curve phase difference light receiving elements) corresponding to the phase difference Pdif of the characteristic curve is defined as Y. In the specific example of this embodiment, Y = 8. Y is a value proportional to the positional deviation Z of the adjustment pattern and the characteristic curve 1 period λ described above.

  Then, the light emission position deviation control unit 190 calculates the first adjustment pattern from the one-cycle line number X, the one-cycle light receiving element number X ′, the characteristic curve phase difference light receiving element number Y, and the light receiving element pitch p obtained as described above. A positional deviation Z in the main scanning direction between (a1) and the second adjustment pattern (a2) is calculated (step S108 in FIG. 8).

Reference is now made to FIG. 11, which is a drawing showing the same state as FIG. In FIG. 11, the adjustment pattern lines are also counted sequentially from the light receiving element # 1 side.
In the first adjustment pattern (a1), the first black line coincides with the light receiving element # 1. On the other hand, in the second adjustment pattern (a2) having the phase difference Pdif (= Yp = 8p), the fifth black line (the 9th line if the black line and the blank line are each 1 line (2 lines in total)). Corresponds to the light receiving element # 9.

In this state, in the first adjustment pattern (a1), the distance between the ends (starting end to end of the main scanning direction) of the four black lines and the four blank lines (total of 8 lines) is 8 (p + δp). .
In this state, if the first black line of the second adjustment pattern (a1) is changed to the fifth black line of the adjustment pattern (a2) (one black line and one blank line each (2 lines in total)), 9 lines The distance between both ends (the start line to the end line in the main scanning direction) of the eye line is Yp.

  Further, the fifth black line (black line) of the fifth adjustment pattern (a1) and the fifth black line (black line if the black line and the blank line are each one line) and the fifth black line (black line) of the second adjustment pattern (a2). And the blank line is one line each, the distance between the ninth line) is the main scanning direction positional deviation Z.

Therefore, when the above formulas are arranged, as is clear from FIG.
λ = X (p + δp) = X′p = (X + δx) p.

By transforming this equation,
Let δp = (δx / X) p.
In addition, regarding the characteristic curve phase difference light receiving element number Y,
Y (p + δp) = Yp + Z.

Also, if this equation is transformed,
Z = Yδp.
Therefore, in the above Z = Yδp,
Substituting δp = (δx / X) p described above,
Z = ((δx · Y) / X) p or
Z = (((X′−X) · Y) / X) p.

  That is, the positional deviation Z in the main scanning direction between the first adjustment pattern (a1) and the second adjustment pattern (a2) is represented by one cycle line number X, one cycle light receiving element number X ′, and characteristic curve phase difference light receiving element number Y. , From the light receiving element pitch p.

  For example, when the reading unit 110 is composed of a light receiving element array of 600 dpi, the light receiving element pitch p = 42.3 μm. Here, when an image forming apparatus of 1200 dpi is used, a repetitive adjustment pattern of two black lines and two blank lines is created.

At this time, it is assumed that the number of one-cycle lines X = 100, the number of one-cycle light receiving elements X ′ = 102, and the number of characteristic curve phase difference light-receiving elements Y = 10.
In this case, the displacement Z in the main scanning direction between the first adjustment pattern (a1) and the second adjustment pattern (a2) is Z = ((δx · Y) / X)) p = (2 · 10/100). × 42.3 μm = 8.5 μm.

  In this case, the light receiving element pitch p of the reading unit 110 can obtain an accurate value from the manufacturer as the characteristic of the sensor of the reading unit 110. In addition, since the characteristic curve is obtained from the light receiving signal value of each light receiving element, the number of one period line X, the number of one period light receiving element X ′, and the characteristic curve phase difference light receiving element number Y are sufficiently accurate values. Become.

Further, since Z is projected onto X and Y that are sufficiently larger than Z confidence, the influence of the error becomes extremely small.
Further, since the specific received light signal value itself is not used and the value of δp, which is the pitch difference, is not directly used for the final calculation, the influence of the error is extremely small.

  Furthermore, in this embodiment, since Z is calculated as an absolute value by calculation, a series of processes of adjustment pattern formation, reading, Z calculation, and adjustment value determination need only be performed once. In other words, it is not necessary to perform a process for repeating the relative adjustment to converge the error. Therefore, the adjustment can be completed in a very short time.

  The light emission position deviation control unit 190 is necessary to eliminate this Z from the position deviation Z in the main scanning direction of the first adjustment pattern (a1) and the second adjustment pattern (a2) obtained as described above. A light emission timing adjustment value is calculated and notified to the laser controller 130 (step S109 in FIG. 8). The adjustment value can be obtained by calculation from the calculated positional deviation Z and the scanning speed of the laser beam on the photosensitive drum 181.

  Although not shown in the flowchart, when the calculated misalignment Z exceeds a predetermined reference value, the light emission misalignment control unit 190 does not calculate the adjustment value with respect to the operation unit 105. An error display may be performed to prompt the replacement of the rotary polygon mirror 174.

  In addition, although the part which calculates the position shift between the first adjustment pattern and the second adjustment pattern and sets the adjustment value has been described, the third adjustment is similarly performed between the second adjustment pattern and the third adjustment pattern. An adjustment value is set by calculating a positional deviation between the pattern and the fourth adjustment pattern, between the fourth adjustment pattern and the fifth adjustment pattern, and between the fifth adjustment pattern and the sixth adjustment pattern. Thereby, the dot position shift in each reflective surface of the rotary polygon mirror 174 is eliminated.

  Further, as shown in FIG. 5, in a plurality of regions in the main scanning direction, between the first adjustment pattern and the second adjustment pattern, between the second adjustment pattern and the third adjustment pattern, and the third adjustment pattern, An adjustment value is set by calculating a positional deviation between the fourth adjustment pattern, between the fourth adjustment pattern and the fifth adjustment pattern, and between the fifth adjustment pattern and the sixth adjustment pattern. Thereby, the dot position shift on each reflecting surface of the rotary polygon mirror 174 is eliminated in a plurality of regions in the main scanning direction.

  The light emission position deviation control unit 190 notifies the overall control unit 101 of the completion of adjustment after notifying the laser control unit 130 of the adjustment value of the light emission timing. Thereby, the overall control unit 101 controls each unit of the image forming apparatus 100 to return to the normal operation (adjustment end in FIG. 8).

  At the time of image formation in the normal mode, the laser control unit 130 adjusts the light emission timing of the laser diode 171 in consideration of the notified adjustment value, so that each reflection of the rotary polygon mirror 174 shown in FIGS. It is possible to eliminate a dot position shift on the surface and form a good image.

[Other Embodiments]
In the above description, between the first adjustment pattern and the second adjustment pattern, between the second adjustment pattern and the third adjustment pattern, between the third adjustment pattern and the fourth adjustment pattern, and between the fourth adjustment pattern and the second adjustment pattern. The adjustment value is set by calculating the positional deviation between the fifth adjustment pattern and between the fifth adjustment pattern and the sixth adjustment pattern, but the present invention is not limited to this. For example, on the basis of the first adjustment pattern, between the first adjustment pattern and the second adjustment pattern, between the first adjustment pattern and the third adjustment pattern, between the first adjustment pattern and the fourth adjustment pattern, An adjustment value may be set by calculating a positional deviation between the first adjustment pattern and the fifth adjustment pattern, and between the first adjustment pattern and the sixth adjustment pattern.

Note that the function of the light emission position deviation control unit 190 in the above description can be incorporated in the overall control unit 101.
Further, the function of the light emission position deviation control unit 190 in the above description can be realized by the image forming control device 300 outside the image forming device 100. In this case, the image forming control device 300 may calculate the positional deviation of the adjustment pattern and set the adjustment value for the image forming device 100.

  In order to achieve high resolution and high productivity of image formation, the laser diode 171 may be configured to include a plurality of light emitting units that are inclined with respect to the sub-scanning direction. In this case, the laser control unit 130 adjusts the light emission timing according to the inclination of the light emitting unit (difference in position in the main scanning direction). In this case, the adjustment value from the light emission position deviation control unit 190 of this embodiment may be added to the light emission timing adjustment for this inclination.

In the case of a color image forming apparatus that superimposes images of a plurality of colors, it is desirable to perform the above adjustment for each color.
Further, the above embodiment is preferably used for an electrophotographic image forming apparatus using a laser beam, but in addition to this, there are various types such as a laser imager that exposes photographic paper using a laser beam. Each of the embodiments of the present invention can be applied to the image forming apparatus, and good results can be obtained.

  Further, the present invention can be applied even when a light source other than the laser diode (LD) is used as the light source.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Overall control part 103 Storage part 105 Operation part 110 Reading part 120 Image processing part 130 Laser control part 140 Print engine 150 Print head 160 Laser drive circuit 170 Optical system 180 Process unit 190 Light emission position shift control part 300 Image formation Control device

Claims (12)

An image carrier on which an image is formed on the surface by receiving a light beam scanned in a second direction orthogonal to the first direction in a state driven in the first direction;
A light emitting unit for generating the light beam;
A first scanning unit for driving the image carrier in the first direction;
A second scanning unit that irradiates the image carrier while scanning the light beam in the second direction by reflecting the light beam with a plurality of reflecting surfaces included in the rotary polygon mirror;
A transfer unit that converts an image formed by irradiating the light beam onto the image carrier into a visible image and transfers the visible image to paper;
An image forming control apparatus for controlling an image forming apparatus having
A control unit that controls the scanning of the first scanning unit and the scanning of the second scanning unit and also controls the light emission timing of the light emitting unit,
The controller is
When any one of the reflection surfaces included in the rotary polygon mirror is a jth reflection surface, and any one of the reflection surfaces different from the jth reflection surface is a kth reflection surface,
An image of the jth adjustment pattern that alternately repeats light emission and no light emission in the second direction by the jth reflective surface, and kth image that alternately repeats light emission and light emission in the second direction by the kth reflective surface. Controlling the light emitting unit to generate an image of the adjustment pattern at the same light emission timing in the second direction;
The reading unit corresponding to a characteristic curve of a received light signal level obtained by reading an image of the jth adjustment pattern and an image of the kth adjustment pattern by a reading unit, a light receiving element pitch of the reading unit, and one cycle of the characteristic curve. , The number of repetitions of the adjustment pattern corresponding to one period of the characteristic curve, the number of light reception elements corresponding to the phase difference, and the phase difference between the characteristic curves of the jth adjustment pattern and the kth adjustment pattern Seeking,
Calculating a positional deviation in the second direction between the image of the jth adjustment pattern and the image of the kth adjustment pattern;
An image formation control apparatus characterized by that. The control unit controls to generate the j-th adjustment pattern and the k-th adjustment pattern at least on the scanning end side in the second direction;
The image forming control apparatus according to claim 1. The controller controls to generate the j-th adjustment pattern and the k-th adjustment pattern in correspondence with each other in a plurality of regions in the second direction;
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The control unit includes the j-th adjustment pattern and the k-th adjustment so that the plurality of regions in the second direction include at least one of a scanning start end side and a scanning end side of the paper to be used in the second direction. Control to generate corresponding patterns,
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The controller is
The light emitting unit is controlled so as to generate an image of an adjustment pattern that alternately repeats light emission and light emission in the second direction, and the pitch of the light receiving elements included in the reading unit is p, and light emission in the adjustment pattern is present. And the pitch of no light emission is controlled to be p + δp, where δp <p.
X ′ represents the number of light receiving elements in the reading unit corresponding to one period of the characteristic curve, X represents the number of repetitions of the adjustment pattern corresponding to one period of the characteristic curve, and Y represents the number of light receiving elements corresponding to the phase difference. As sought
The displacement Z in the second direction is calculated as Z = (((X′−X) · Y) / X) p.
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The characteristic curve includes an odd characteristic curve connecting light reception signal values of odd-numbered light receiving elements and an even characteristic curve connecting light reception signal values of even-numbered light receiving elements.
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The controller is
When the number of reflecting surfaces included in the rotary polygon mirror is M,
Changing the driving speed of the image carrier in the first direction by the first scanning unit to 1 / M of normal time;
Controlling the image of the j-th adjustment pattern and the image of the k-th adjustment pattern to be generated as a continuous state by repeating a plurality of times in the first direction, respectively.
The image formation control apparatus according to claim 1, wherein The control unit controls to generate the j-th adjustment pattern and the k-th adjustment pattern corresponding to one period of the characteristic curve in the second direction;
The image forming control apparatus according to claim 1, wherein The control unit adjusts the light emission timing of the light emitting unit for each of the reflection surfaces so as to eliminate the calculated displacement.
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The control unit calculates the positional deviation for each of the adjacent reflecting surfaces included in the rotary polygon mirror, and cancels the positional deviation calculated for each of the adjacent reflecting surfaces. Adjusting the light emission timing of the light emitting unit,
The image formation control apparatus according to claim 1, wherein the image formation control apparatus is an image formation control apparatus. The control unit according to any one of claims 1 to 10,
An image carrier on which an image is formed on the surface by receiving a light beam scanned in a second direction orthogonal to the first direction in a state driven in the first direction;
A light emitting unit for generating the light beam;
A first scanning unit for driving the image carrier in the first direction;
A second scanning unit that irradiates the image carrier while scanning the light beam in the second direction by reflecting the light beam with a plurality of reflecting surfaces included in the rotary polygon mirror;
A transfer unit that converts an image formed by irradiating the light beam onto the image carrier into a visible image and transfers the visible image to paper;
An image forming apparatus comprising: The image forming apparatus according to claim 11, further comprising a reading unit that reads an image of the jth adjustment pattern and an image of the kth adjustment pattern.