JP2010039197A - Printing method of color shift check chart and auxiliary detection lines - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily check the color shifts even when they are narrower than a pixel. <P>SOLUTION: The m auxiliary base lines (c) of a pixel width (h) are printed almost in parallel with the reference breakdown color between adjacent base lines (a). The m auxiliary detection lines (d) of a pixel width are printed almost in parallel with the detected breakdown color between adjacent detection lines (b). The auxiliary detection lines adjoining the k-th line obtained by counting the non-standard detection lines (b2) and the auxiliary detection lines (d) to the standard detection line (b1) are shifted from the auxiliary base lines adjoining the k-th line obtained by counting the non-standard base lines (a2) and the auxiliary base lines c to the standard base line (a1) in a certain direction by the distance k/(m+1) times the pixel width (h) when printing the standard base lines (a1) and the standard detection lines (b1) by arranging them almost in a straight line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention scans the image carrier with a laser beam along the rotation axis direction at a substantially constant scanning pitch along the rotation direction, and forms an electrostatic latent image corresponding to each of a plurality of separation colors, A specific reference of the plurality of separation colors in an image forming apparatus configured to print a color image on which a toner image for each separation color formed based on the electrostatic latent image is superimposed on a recording medium In order to confirm the color shift amount of the toner image for each remaining separation color with respect to the separation-color toner image, the reference separation color, the width of one pixel, an integer multiple of the width of one pixel, etc. A reference line pattern having a plurality of reference lines composed of a single standard reference line and a plurality of non-standard reference lines printed substantially parallel to each other at a pitch, and a detected separation color other than the reference separation color, and The width of the one pixel is equal to each other at an equal pitch that is an integral multiple of the width of the one pixel. And a plurality of non-standard detection lines and a plurality of non-standard detection lines, and the standard reference lines and the standard detection lines are printed in a substantially straight line. Each of the nth non-standard detection lines adjacent to the standard detection line has a width of one pixel with respect to the non-standard reference line nth adjacent to the standard reference line. A detection line pattern printed at a position shifted in a predetermined direction by a distance of n times is adjacent to the longitudinal direction of the reference line, and a color misregistration amount confirmation chart and auxiliary detection printed on a recording medium by the image forming apparatus The present invention relates to a line printing method.

The color misregistration amount confirmation chart is printed on a recording medium by reading the printing data from a memory provided in the image forming apparatus.
When the standard reference line and the standard detection line are printed in a substantially straight line, the image forming apparatus on which the color misregistration amount confirmation chart is printed corresponds to the print color of the standard detection line for the toner image of the reference separation color. It can be confirmed that there is no color shift of the separation color toner image.
When the non-standard reference line and the non-standard detection line are printed in a substantially straight line, the number of the non-standard reference line adjacent to the standard reference line, or the non-standard detection line is the standard detection line. In the image forming apparatus on which the color misregistration amount confirmation chart is printed, for example, in the case of the nth adjacent, the nonstandard detection line is compared with the nonstandard reference line. It can be easily confirmed that color misregistration has occurred in a direction opposite to the shifted direction by a distance n times the width of one pixel.
When it is confirmed that the color misregistration has occurred, the image forming apparatus is adjusted based on the color misregistration amount so as not to cause the color misregistration.
The conventional color misregistration amount confirmation chart is configured so that the color misregistration amount can be confirmed in a unit of width for one pixel (for example, see Patent Document 1).

JP-A-8-262829

Therefore, in actuality, color misregistration occurs in a width narrower than the width of one pixel, or a width obtained by adding a width that is an integral multiple of the width of one pixel and a width that is narrower than the width of one pixel. Even if color misregistration occurs, the image forming apparatus must be adjusted based on the color misregistration amount confirmed in units of width for one pixel.
As a result, since the color misalignment having a width smaller than the width of one pixel cannot be eliminated, there is a drawback that the image forming apparatus cannot be adjusted with high accuracy so that a high-quality color image with little color misregistration can be formed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to easily confirm even a color shift having a width narrower than the width of one pixel.

The first feature of the present invention is that the image carrier is scanned with a laser beam at a substantially constant scanning pitch along the rotation direction along the rotation axis direction, and an electrostatic latent image corresponding to each of a plurality of separation colors is obtained. An image forming apparatus configured to print a color image on a recording medium, wherein an image is formed and a toner image for each separation color formed based on the electrostatic latent image is superimposed. In order to check the color shift amount of the toner image for each remaining separation color with respect to the toner image of the specific reference separation color, the width of the one pixel with the reference separation color and the width of one pixel A reference line pattern having a plurality of reference lines composed of a single standard reference line and a plurality of non-standard reference lines that are printed substantially in parallel with each other at an equal pitch of an integral multiple of the detection, and detection other than the reference separation color The separation color and the width of the one pixel, which is an integer multiple of the width of the one pixel It has a plurality of detection lines consisting of a single standard detection line and a plurality of non-standard detection lines that are printed substantially parallel to each other at an equal pitch, and the standard reference line and the standard detection line are substantially in a straight line. When printed side by side, each of the nth non-standard detection lines adjacent to the standard detection line corresponds to one pixel with respect to the nth non-standard reference line adjacent to the standard reference line. A detection line pattern printed at a position shifted in a predetermined direction by a distance n times the width of the reference line is adjacent to the longitudinal direction of the reference line and is printed on a recording medium by the image forming apparatus. Because
Each of the adjacent reference lines is provided with m auxiliary reference lines that are printed in parallel with the reference separation color and the width of the one pixel, and the adjacent detection lines. M auxiliary detection lines that are printed in substantially parallel with the detection separation color and the width corresponding to the one pixel are provided between each of the two, and the non-standard detection is performed with respect to the standard detection line. The standard reference line is printed when the standard reference line and the standard detection line are printed with the standard reference line and the standard detection line arranged substantially in line with each of the kth adjacent auxiliary detection lines including the line and the auxiliary detection line. With respect to the auxiliary reference line adjacent to the kth, including the non-standard reference line and the auxiliary reference line, in a fixed direction by a distance of k / (m + 1) times the width of one pixel. It is in the point arranged so that it may be printed in the shifted position.

[Action and effect]
That is, as illustrated in FIG. 3, m auxiliary reference lines c that are printed in parallel with a reference separation color and a width h of one pixel are provided between adjacent reference lines a. M auxiliary detection lines (one in FIG. 3) that are provided and are printed in parallel between each detection line b with a detection separation color and a width h of one pixel. d is provided.
Each of the kth auxiliary detection lines d including the non-standard detection line b2 and the auxiliary detection line d with respect to the standard detection line b1 is substantially aligned with the standard reference line a1 and the standard detection line b1. When printed side by side, the standard reference line a1 including the non-standard reference line a2 and the auxiliary reference line c is counted, and the auxiliary reference line c adjacent to the k-th has a width h of one pixel. It is arranged so that it is printed at a position shifted in a certain direction by a distance of k / (m + 1) times.
Therefore, as illustrated in FIG. 3, when the standard reference line a1 and the standard detection line b1 are printed in a substantially straight line, the reference separation color toner is printed in the image forming apparatus on which the color misregistration amount confirmation chart is printed. It can be confirmed that there is no color shift of the separated color toner image corresponding to the print color of the standard detection line b1 with respect to the image.
Then, when the non-standard reference line a2 and the non-standard detection line b2 are printed in a substantially straight line, the number of the non-standard reference line a2 adjacent to the standard reference line a1 or the non-standard reference line a1. By knowing what position the detection line b2 is adjacent to the standard detection line b1, for example, when the detection line b2 is adjacent to the standard detection line b1, in the image forming apparatus on which the color misregistration amount confirmation chart is printed, It can be easily confirmed that color misregistration has occurred by a distance n times the width of one pixel in the direction opposite to the direction in which b2 is shifted with respect to the non-standard reference line a1.
Further, as illustrated in FIG. 4, the auxiliary reference line c adjacent to the standard reference line a1, including the non-standard reference line a2 and the auxiliary reference line c, and the standard detection line b1. When the non-standard detection line b2 and the auxiliary detection line d and the auxiliary detection line d adjacent to the kth are printed in a substantially straight line, the image forming apparatus on which the color misregistration amount confirmation chart is printed is printed. In addition, it is easy to confirm that color misregistration has occurred by a distance of k / (m + 1) times the width h of one pixel in the direction opposite to the direction in which the auxiliary detection line d is shifted from the auxiliary reference line c. can do.
Therefore, when the auxiliary reference line and the auxiliary detection line are printed in a substantially straight line, the auxiliary detection line is counted from the standard detection line, including the non-standard detection line and the auxiliary detection line. Or the auxiliary reference line is counted by including the non-standard reference line and the auxiliary reference line with respect to the standard reference line. The amount of color misregistration can be confirmed in units of / (m + 1), and even a color misregistration having a width smaller than the width of one pixel can be easily confirmed.

A second characteristic configuration of the present invention is an auxiliary detection line printing method for confirming a color misregistration amount along the sub-scanning direction in the color misregistration amount confirmation chart according to claim 1,
In order to print the auxiliary detection lines by scanning the image carrier with a laser beam having a smaller amount of light than when forming an electrostatic latent image for normal printing at every scanning pitch adjacent in the rotation direction of the image carrier. Is formed as a combined electrostatic latent image obtained by combining two electrostatic latent images formed at adjacent scanning pitches in the rotation direction of the image carrier, and the toner of the combined electrostatic latent image The point is that the image is printed on the recording paper.

[Action and effect]
When printing each auxiliary detection line at a position shifted in a fixed direction in units of 1/2 of the width of one pixel with respect to the auxiliary reference line, a color shift along the main scanning direction (laser light scanning direction). The auxiliary detection lines printed for confirming the amount can be easily printed by adjusting the irradiation timing of the laser beam on the image carrier.
However, in the conventional image forming apparatus, the auxiliary reference line and the auxiliary detection line for confirming the amount of color misregistration along the sub-scanning direction (direction orthogonal to the laser beam scanning direction) have a width corresponding to one pixel, and Since the toner image of the electrostatic latent image formed by the laser beam scanned along the rotation axis direction at a constant scanning pitch of one pixel width is printed, the auxiliary detection line is set to 1 with respect to the auxiliary reference line. There is a problem that printing cannot be performed by shifting the position by 1/2 unit of the width of the pixel.
Therefore, for each scanning pitch adjacent in the rotation direction of the image carrier set in accordance with the resolution of the image forming apparatus, the image carrier is made with a laser beam having a smaller amount of light than when forming an electrostatic latent image for normal printing. A combined electrostatic latent image obtained by combining two electrostatic latent images formed at every scanning pitch adjacent in the rotation direction of the image carrier into an electrostatic latent image for printing auxiliary detection lines. And the toner image of the combined electrostatic latent image is printed on a recording sheet.
Therefore, regardless of the width of one pixel set according to the resolution of the image forming apparatus, the auxiliary detection line whose position is shifted by about ½ unit of the width of one pixel with respect to the auxiliary reference line. Can be printed.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 illustrates an image forming apparatus configured to print a full color image in which toner images for each of a plurality of separation colors (four separation colors of yellow, magenta, cyan, and black) are superimposed on a recording sheet 1 as a recording medium. An electrophotographic copying machine 2 is shown.

The copying machine 2 includes a main body unit 3, an operation unit 4, a document reading unit 5, a document feeding unit 6, and the like.
The image data of the document read by the document reading unit 5 is decomposed into image data for each of four separation colors and output to the main body unit 3.

  The main body 3 includes a plurality of paper feed cassettes 7, a transfer roller 8, a photosensitive drum 9 as an image carrier, an exposure device 10, a developing device 11, a fixing roller 12, a paper discharge tray 13, a recording paper transport unit 14, and the like. I have.

  The photosensitive drum 9 is uniformly charged by a charging device (not shown) while rotating in the direction of the arrow. The exposure apparatus 10 scans the photosensitive drum 9 with a substantially constant scanning pitch along the rotation direction, that is, a width h of one pixel, with laser light output based on image data for each of the four separated colors. An electrostatic latent image corresponding to each separation color is formed on the photosensitive drum 9 by scanning along the rotation axis direction at a pitch.

  The developing device 11 supplies a developer for each separated color to the photosensitive drum 9 to form a toner image for each separated color.

  The recording paper transport unit 14 transports the recording paper 1 drawn from the paper feed cassette 7 by the paper feed roller 7 a toward the transfer roller 8, then transports it toward the fixing roller 12, and discharges it to the paper discharge tray 13. To do.

  The transfer roller 8 transfers the color toner image formed by superimposing the toner images for the respective separation colors formed on the photosensitive drum 9 onto the recording paper 1. The color toner image transferred to the recording paper 1 is printed on the recording paper 1 as a full-color image by being heated and fixed by the fixing roller 12.

2 and 3 show the copying machine 2 in order to confirm the color misregistration amount of the remaining three separation colors with respect to the black toner image as a specific reference separation color among the four separation colors. 2 is a color misregistration amount confirmation chart printed on the recording paper 1 according to the present invention.
The image data of the color misregistration amount confirmation chart is stored in advance in a memory provided in the copying machine 2 or the like.

  The color misregistration amount confirmation chart is printed with a reference line pattern 15 printed with black as a reference separation color and the detected separation colors of yellow, magenta, and cyan, which are separation colors other than black. The detection line pattern 16 is combined.

  The detection line pattern 16 is printed on the recording paper 1 adjacent to the longitudinal direction of the reference line a in the reference line pattern 15 as a color misregistration check chart 17 for each separation color combined with the reference line pattern 15 for each detected separation color. Is done.

  Therefore, the color misregistration amount confirmation chart is composed of three separation color-specific color misregistration amount confirmation charts 17 printed corresponding to yellow, magenta, and cyan, respectively. In FIG. 2, for example, only the color misregistration amount confirmation chart 17 for each separation color corresponding to yellow is illustrated in FIG.

  In FIG. 2, the separation-color-specific color misregistration amount confirmation chart denoted by reference numeral 17a is a chart printed for confirming color misregistration in the sub-scanning direction, that is, in a direction orthogonal to the laser light scanning direction. The separation-color-specific color misregistration amount confirmation chart 17b is a chart printed for confirming color misregistration in the main scanning direction, that is, in the laser light scanning direction.

  FIG. 3 shows an enlarged view of the color misregistration amount confirmation chart 17a for each separated color. The color misregistration amount confirmation chart 17b for each separated color is rotated at an angle of 90 degrees with respect to the color misregistration amount confirmation chart 17a for each separated color. Since it differs only in that it is printed in the posture, its enlarged view is omitted.

The reference line pattern 15 has a width h for one pixel, and a single standard reference line that is printed substantially in parallel with each other at an equal pitch Pa that is an integer multiple of the width h for one pixel (30 times in this embodiment). There are a plurality (eight in this embodiment) of reference lines a composed of a1 and a plurality of (in this embodiment, seven) non-standard reference lines a2.
Note that the width h for one pixel is a width corresponding to the outer diameter of the beam spot on the drum surface of the laser light irradiated on the photosensitive drum 9.

A number “0” is attached to the standard reference line a1, and the four non-standard reference lines a2 arranged on one side across the standard reference line a1 are in order from the closest to the standard reference line a1. Numbers of “+1.0”, “+2.0”, “+3.0”, “+4.0” are attached, and three non-standard reference lines arranged on the other side across the standard reference line a1 The numbers “−1.0”, “−2.0”, and “−3.0” are attached to a2 in order from the one closest to the standard reference line a1.

  The detection line pattern 16 has a width h for one pixel and is a single standard detection line that is printed substantially in parallel with each other at an equal pitch Pb that is an integral multiple (31 times in this embodiment) of the width h for one pixel. It has a plurality (eight in this embodiment) of detection lines b composed of b1 and a plurality (seven in this embodiment) of non-standard detection lines b2.

The number “0” is attached to the standard detection line b1, and the four non-standard detection lines b2 arranged on one side across the standard detection line b1 are in order from the closest to the standard detection line b1. Numbers of “+1.0”, “+2.0”, “+3.0”, “+4.0” are attached, and three non-standard detection lines arranged on the other side across the standard detection line b1 The numbers “−1.0”, “−2.0”, and “−3.0” are attached to b2 in order from the closest to the standard detection line b1.

  Each of the n-th non-standard detection lines b2 adjacent to the standard detection line b1 is printed when the standard reference line a1 and the standard detection line b1 are arranged substantially in a straight line, that is, when no color misregistration occurs. The non-standard reference line a2 adjacent to the standard reference line a1 is printed at a position shifted in a fixed direction by a distance n times the width h of one pixel.

Therefore, when the non-standard reference line a2 and the non-standard detection line b2 having the same numbers are printed in a substantially straight line, the detected separation color image is one pixel worth of the reference separation color image. It can be confirmed that the distance h is shifted by a distance corresponding to the product of the width h and the attached number.
When the value of the product of the width h for one pixel and the number attached thereto is positive, the color misregistration amount confirmation chart for each separation color in the direction of the arrow D1 in the color misregistration amount confirmation chart 17a for each separation color. In 17b, each shifts in the direction of the arrow E1, and when the product value is negative, in the color separation amount confirmation chart 17a for each separated color, in the direction of the arrow D2, in the color deviation amount confirmation chart 17b for each separated color. It can be confirmed that they are shifted in the direction of the arrow E2.

  The reference line pattern 15 includes an integer multiple of the width h of one pixel with a reference separation color and a width h of one pixel between the adjacent reference lines a (15 in this embodiment). (M) (one in this embodiment) auxiliary reference lines c are provided which are printed substantially in parallel with each other at an equal pitch Pc.

  In the detection line pattern 16, m lines (books) are printed between the adjacent detection lines b with detection separation color and with a width h of one pixel and in parallel with each other at intervals. In the embodiment, one auxiliary detection line d is provided at an equal pitch Pd that is 15.5 times the width h of one pixel.

  Accordingly, each of the kth auxiliary detection lines d including the non-standard detection line b2 and the auxiliary detection line d with respect to the standard detection line b1 is substantially the same as the standard reference line a1 and the standard detection line b1. When printed in a straight line, that is, when there is no color misregistration, the auxiliary reference line adjacent to the standard reference line a1 including the non-standard reference line a2 and the auxiliary reference line c is adjacent to the kth. It is arranged so that it is printed at a position shifted in a certain direction by a distance k / (m + 1) times (k / 2 in this embodiment) times the width h of one pixel with respect to c.

  The four auxiliary reference lines c arranged on one side across the standard reference line a1 are “+0.5”, “+1.5”, “+2.5”, “ +3.5 "is attached, and the four auxiliary reference lines c arranged on the other side across the standard reference line a1 are" -0.5 "in order from the closest to the standard reference line a1. , “−1.5”, “−2.5”, “−3.5”.

  The four auxiliary detection lines d arranged on one side with the standard detection line b1 interposed therebetween are “+0.5”, “+1.5”, “+2.5”, “+” in order from the closest to the standard detection line b1. The number of the four auxiliary detection lines d arranged on the other side of the standard detection line b1 is “−0.5” in order from the closest to the standard detection line b1. , “−1.5”, “−2.5”, “−3.5”.

  Therefore, when the auxiliary reference line c and the auxiliary detection line d having the same numbers are printed in a substantially straight line, the detected separation color image is one pixel wide with respect to the reference separation color image. When the product value is positive, the distance corresponding to the product of h and the number attached is shifted in the direction of the arrow D1, and when the product value is negative, it is shifted in the direction of the arrow D2. I can confirm that.

FIG. 4 exemplifies a color misregistration amount confirmation chart 17a for each separation color printed on the recording paper 1 to confirm color misregistration in the sub-scanning direction, for example, the detected separation color is yellow.
As shown in the figure, the auxiliary reference line c with “+1.5” and the auxiliary detection line d with “+1.5” are printed in a substantially straight line.
Therefore, it can be confirmed that the detected separation color image is shifted in the direction of the arrow D1 by a distance of 1.5 times the width h of one pixel with respect to the reference separation color image.

  The auxiliary detection line d for confirming the color misregistration amount along the sub-scanning direction in the color misregistration amount confirmation chart 17a is normally printed at every scanning pitch of the width h for one pixel adjacent in the rotation direction of the photosensitive drum 9. The photosensitive drum 9 is scanned with a laser beam having a light amount smaller than that for forming an electrostatic latent image for use, that is, a laser beam having a resolution of 1/2 pixel with respect to the machine specification by applying pulse width modulation, and assisting. Forming an electrostatic latent image for printing the detection line d as a combined electrostatic latent image in which two electrostatic latent images formed at every scanning pitch adjacent in the rotation direction of the photosensitive drum 9 are combined; The toner image of the combined electrostatic latent image is printed on the recording paper 1.

For example, when the auxiliary detection line d with the number “0.5” is printed at a position shifted from the standard detection line b1 by a distance of 15.5 times the width h of one pixel, the photosensitive drum 9 On the other hand, a pulse width shorter than normal, for example, normal, at a position shifted by 15 pixels in the sub-scanning direction and a position shifted by 16 pixels from the position where the laser beam corresponding to the standard detection line b1 is scanned. The laser beam is scanned with a pulse width of 25% of the pulse width.
Then, the electrostatic latent image for printing the auxiliary detection line is statically generated by these two laser beams at a position shifted by 15.5 pixels in the sub-scanning direction from the position where the laser beam corresponding to the standard detection line b1 is scanned. The electrostatic latent image is formed as a combined electrostatic latent image.

[Other Embodiments]
1. The color misregistration amount confirmation chart according to the present invention may be printed in advance on a sheet such as paper when confirming the color misregistration amount in the copying machine.
That is, the color misregistration amount in the copying machine can be confirmed by copying the color misregistration amount confirmation chart printed on the sheet and printing it on the recording paper.
2. The color misregistration amount confirmation chart according to the present invention may be printed for confirming the color misregistration amount in an image forming apparatus provided with a photosensitive belt as an image carrier.
3. The color misregistration amount confirmation chart according to the present invention may be printed to confirm the color misregistration amount in an electrophotographic printer or fax machine as an image forming apparatus.

Schematic side view showing inside of image forming apparatus Plan view of color misregistration amount confirmation chart Main part enlarged plan view of color misregistration amount confirmation chart Main part enlarged plan view of color misregistration amount confirmation chart printed on recording medium

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording medium 2 Image forming apparatus 9 Image carrier 15 Reference line pattern 16 Detection line pattern a Reference line a1 Standard reference line a2 Non-standard reference line b Detection line b1 Standard detection line b2 Non-standard detection line c Auxiliary reference line d Auxiliary detection Line h 1 pixel width (scanning pitch)

Claims (2)

The image carrier is scanned with the laser beam along the rotation axis direction at a substantially constant scanning pitch along the rotation direction to form an electrostatic latent image corresponding to each of a plurality of separation colors. A toner having a specific reference separation color among the plurality of separation colors in an image forming apparatus configured to print a color image on which a toner image of each separation color formed based on an image is superimposed on a recording medium In order to confirm the color shift amount of the toner image for each remaining separation color with respect to the image,
One standard reference line and a plurality of non-standard reference lines that are printed in substantially parallel to each other at the same separation pitch and at an equal pitch that is an integral multiple of the width of one pixel. A reference line pattern having a plurality of reference lines comprising:
One standard detection line and a plurality of detection detection colors other than the reference separation color, which are printed in parallel with each other at an equal pitch that is an integral multiple of the width of one pixel, with a width of one pixel. And having a plurality of detection lines consisting of non-standard detection lines of
When the standard reference line and the standard detection line are printed in a substantially straight line, each of the n-th non-standard detection lines adjacent to the standard detection line is nth relative to the standard reference line. A detection line pattern printed at a position shifted in a certain direction by a distance n times the width of one pixel with respect to a non-standard reference line adjacent to
A color misregistration amount confirmation chart printed on a recording medium by the image forming apparatus adjacent to the longitudinal direction of the reference line,
M auxiliary reference lines that are printed in substantially parallel with the reference separation color and the width of the one pixel are provided between the adjacent reference lines, and
M auxiliary detection lines that are printed in substantially parallel with the detection separation color and the width of the one pixel are provided between the adjacent detection lines, respectively.
Each of the auxiliary detection lines adjacent to the standard detection line, including the non-standard detection line and the auxiliary detection line, that are adjacent to the kth,
When the standard reference line and the standard detection line are printed in a substantially straight line, the k-th adjoining the standard reference line including the non-standard reference line and the auxiliary reference line is included. 7 is a color misregistration amount confirmation chart arranged so as to be printed at a position shifted in a certain direction by a distance of k / (m + 1) times the width of one pixel with respect to the auxiliary reference line. An auxiliary detection line printing method for confirming a color misregistration amount along the sub-scanning direction in the color misregistration amount confirmation chart according to claim 1,
In order to print the auxiliary detection lines by scanning the image carrier with a laser beam having a smaller amount of light than when forming an electrostatic latent image for normal printing at every scanning pitch adjacent in the rotation direction of the image carrier. Are formed as a combined electrostatic latent image obtained by combining two electrostatic latent images formed at adjacent scanning pitches in the rotation direction of the image carrier,
A method of printing auxiliary detection lines for printing a toner image of the combined electrostatic latent image on a recording sheet.

Images