JPH03163430A - Display device for image reading position in image forming device - Google Patents

Abstract

PURPOSE:To check the deviation in the image signal reading position in a scanning direction by reading the image signal of a test original color-coded to two colors in a scanning direction over a prescribed range, respectively integrating the number of CCD picture elements which receive the respective colors and displaying the same on the device. CONSTITUTION:The program mode of a CPU 36 in the system is set at the mode for adjusting the reading position of the image signals and the test original GT color- coded to the two colors is imposed on the original tray by aligning the end Q to the reference line R0 of the original tray and aligning the boundary line LM of the colors to the center display M of a reference plate 4 to execute reading and scanning. The image signals read by the respective sensors of the CCD 12 are subjected to prescribed correction in a correcting circuit 33 and are put via an input selector 34 into the CPU 36 where the signals are converted to binarized data of black and white in a binarization circuit 37b. The data are respectively integrated by an integrator 37c and the results are displayed by the number of the picture elements of the CCD on the display device 40. The quantity and direction of the deviation of the reading position are checked by the difference in the number of the black and white picture elements and are thereby easily adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus such as a digital copying machine, and particularly to an image forming apparatus capable of displaying a deviation in the reading position of an image signal in the scanning direction. The present invention relates to a display device for displaying an image reading position.

[Conventional technology]

For example, in an image forming apparatus such as a digital copying machine, a reference plate is provided at the left end of a document table to display a document setting position so that the document is placed within a predetermined range according to the document size. This reference plate is used in the scanning direction of the optical system (
The function is to set the reference position for starting reading the image signal of a document in the sub-scanning direction (hereinafter referred to as the sub-scanning direction), and to specify the placement position of the document in the direction perpendicular to the scanning direction of the optical system (hereinafter referred to as the main-scanning direction). have.

Further, an optical system including the first and second optical systems is disposed at a predetermined position of the driving member, and a sensor such as a photointerrupter is disposed at a predetermined position within the movement range of the optical system, The first optical system that has moved to the predetermined position is detected and reading of image signals in the sub-scanning direction is started. Since the image signal of the original can be read accurately from the reference position of the document mounting table, the image at the reference position is read when replacing the COD board, photo interlayer, reference plate, etc. during product manufacturing or field maintenance. The mounting positions of the reference plate, the sensor such as the photointerrupter, and the first optical system are adjusted so that the first optical system is detected by the sensor at the timing when the light is incident on the COD. In addition, in order for the image of the document placed at the specified position on the reference plate to be accurately focused on the image reading range of the CCD, and the image signal to be read by the CCD, the center of the document in the main scanning direction is set on the reference plate. The mounting positions of the reference plate and COD are adjusted so that the center of the image reading range of the CCD coincides with the center of the image reading range of the CCD.

Conventionally, the above-mentioned adjustment of the reading position of image signals in the main scanning direction and the sub-scanning direction involves extracting an image signal for one line in the main scanning direction or the sub-scanning direction from an image signal obtained by reading a test document, and then adjusting each of the image signals. The waveform in the scanning direction is displayed on a measuring device such as a high-speed oscilloscope, a logic analyzer, or a D/A converter, and while monitoring the deviation of the reading position of the image signal, the reference plate, sensor, first optical system, and C
This is done by adjusting each mounting position of the OD.

[Problem to be solved by the invention]

By the way, since the above-mentioned high-speed oscilloscopes, logic analyzers, and other measuring instruments are expensive, the manufacturing department is unable to adjust the image signal reading position in the main scanning and sub-scanning directions using inexpensive and easy measuring instruments instead. It is hoped that

In addition, in the service department, it is difficult to transport the measuring equipment to the field due to the expansion of the field that requires maintenance and the limited number of the measuring equipment owned, so it is difficult to carry out the measuring equipment to the field. The reading position of image signals in the scanning direction is often adjusted. For this reason, although it is possible to replace the reference plate for setting the original, the COD board, etc., it is not possible to adjust their mounting positions accurately, making sufficient maintenance difficult.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image reading position display device in an image forming apparatus that can display the deviation of the reading position of an image signal of a document in the scanning direction. do.

[Means to solve the problem]

In order to solve the above problems, the present invention provides an image forming apparatus that generates image data for forming a latent image from an image signal of a document read by an imaging means, and outputs the image data to a photoreceptor to form an image. a binarizing means for binarizing each image signal of the test original read in a predetermined range in the scanning direction by the imaging means and divided into two colors in the scanning direction; , and a display means for displaying the data obtained based on the integration results.

[Effect]

In the image reading position display device of the image forming apparatus configured as described above, a test document that is color-coded in two colors in the scanning direction is read by the imaging means within a predetermined range in the scanning direction, and the image signal is Alternatively, after being binarized into a value of 1, the number of data for each value is accumulated. Then, display data obtained based on this integration result is displayed on the display means.

〔Example〕

An image reading position display device in an image forming apparatus according to the present invention will be described with reference to FIGS. 1 to 8.

FIG. 2 is a diagram showing the overall configuration of a digital copying machine (image formatting device) having an image reading start position display device according to the present invention. In the figure, a document mounting table is formed by a contact glass 2 on the upper surface of a copying machine main body 1, and a reference plate 4 for the original stacking position is provided at the left end thereof. Note that the lower part of the reference plate 4 and the portion 2a of the contact glass 2 of the copying machine main body are white. Further, a document presser 3 is provided for holding down the document G placed facing the contact glass 2. As shown in FIG. 3 (upper perspective view of the digital copying machine), the reference plate 4 is formed with an indication line 4a for the document placement position corresponding to the document size, and is attached to the copying machine body 1 by a screw 41 in the main scanning direction. It is attached to B so that its position can be adjusted. Further, the reference line Ro in the sub-scanning direction A defined by the reference plate 4 is the position at which the CCD 12 starts reading the image signal of the original G. Returning to FIG. 2, an image data reading section composed of a first optical system L1, a second optical system L2, a lens section 11, and a CCD 12 (image data reading device) is arranged in the upper part of the copying machine main body 1. has been done. The first optical system Ll mainly consists of a reflector 5, a halogen lamp 6 (light source), a reflector 7, etc., and the second optical system L2 mainly consists of a reflector 9.10. The second optical systems L1 and L2 are configured to reciprocate in the sub-scanning direction A along the document surface by a drive mechanism (not shown). In the above image data reading section, the halogen lamp 6
Light is irradiated onto the original G by the mirror 7, and the reflected light is reflected by the reflecting mirror 7.
9.10 to the lens section 11, and the lens section 1
An image signal of the document G imaged by the CCD 12 is read by the CCD 12 and stored in a storage device (not shown). The timing to start reading this image signal is determined by a detection signal of the first optical system L1 by the photointerrupter 13 disposed at a predetermined position in the main body 1 of the copying machine. In other words? The photointerchanger 13 is arranged at a position such that the detection signal of the first optical system L1 is output at the timing when the image of the document G on the reference line Ro is incident on the CCD 12. In addition, the first optical system L. A partition plate 8 is attached at a proper position, and when the optical path of the photointerrupter 13 is blocked by the partition plate 8, the first optical system L2 moving forward from the home position is detected. Reading of the image signal of the CCD 12 is started based on the detection signal.

Therefore, the first optical system L1 and the photo interlayer 13
If the respective mounting positions are suitable, reading of the image signal will be started from the reference line Ro based on the detection signal of the photo interrupter 13. Reference numeral 14 denotes a photo interrupter disposed at the stop position of the first optical system L2 on the upstream side (left side in the figure) of document scanning, that is, at the home position. When the first optical system L1 that has moved backward is detected by the photointerlarter 14, the drive of the optical system is stopped by the detection signal, and the first and second optical systems 1, 1, 1.2 are moved to a predetermined position. It is stopped at the home position.

A laser diode 15 is installed at a suitable location in the lower part of the copying machine body 1.
(Image data output device) An image data output section consisting of a polygon mirror 16 and a reflecting mirror 17 is provided. In the image data output section, image data generated by an image processing circuit, which will be described later, is modulated into a laser beam by a laser diode 15 and outputted to a polygon mirror 16, and is line-scanned by rotation of the polygon mirror 16. The light is guided to the photosensitive drum 18 side through the reflecting mirror 17.

An image forming means composed of a transfer mechanism, a paper feed mechanism, and a paper ejection mechanism is disposed at a suitable lower part of the copying machine main body 1. The transfer mechanism includes a photoreceptor drum 18 and a charging device 19.
, a developing device 20, a transfer device 21, a separating device 22, a cleaning device 23, and the like. Charging device 19
After the electrostatic latent image of the image data outputted from the image data output section is formed on the photosensitive drum 18 charged with electricity, the electrostatic latent image of the image data is developed by the developing device 2o. The image data visualized by the transfer device 21 is transferred onto a sheet of paper fed by a paper feeding mechanism. After the transfer paper is separated from the photoreceptor drum 18 by the separation device 22, the transfer paper is ejected to the paper ejection tray 31 via the paper ejection mechanism, and the photoreceptor drum 18 is removed from the surface of the drum by the cleaning device 23. Toner is removed. The paper feed mechanism includes a paper feed cassette 24, a paper feed roller 25, and a paper feed guide 26, which are placed at the bottom of the copying machine main body 1.
and a pair of transport rollers 27, the paper feed roller 2
The paper sent out from the paper feed cassette 24 by 5 is transferred to the photosensitive drum 1 by a paper feed guide 26 and a pair of transport rollers 27.
8. Further, the paper ejection mechanism includes a conveyor belt 28,
The transfer sheet, which is composed of a fixing IE 29 and a pair of paper ejection rollers 30, is separated from the photoreceptor drum 18 by the separating device 22, and is conveyed to a fixing section 29 by a conveying belt 28, and after being fixed in the fixing section 29, The paper is discharged onto a paper discharge tray 31 by a pair of paper discharge rollers 30 .

FIG. 1 shows a system configuration diagram regarding an image reading position display device according to the present invention in the digital copying machine. In this figure, the same members as those shown in FIG. 2 are given the same numbers. 32 is halogen lamp 6
This is an AVR unit that controls the amount of light emitted. The AVR unit 32 controls the amount of light emitted from the halogen lamp 6 so that the amount of light is set by a volume not shown. 33
is a correction circuit that corrects the image signal read by the CCD 12; for example, it corrects the image signal due to variations in the light receiving sensitivity of each pixel composing the CCD 12 or due to deviations in the brightness of the lens section 11. Corrects deviations, etc., and corrects errors in the amount of received light. Reference numeral 34 denotes an input selector for selecting a destination for receiving the image signal, and the image signal is transferred to a subsequent image processing circuit 35 or an image memory 37a in the CPU 36 according to a command signal from a microcomputer 36 (hereinafter referred to as CPU). selectively output.

35 is an image processing circuit that generates image data for forming an electrostatic latent image on the photosensitive drum 18 from the image signal input from the CCD 12. 36 is a CPU that centrally controls the copying operation of the copying machine, and the CCD 12
An image memory 37a1 that stores image signals input from
It has a built-in binarization circuit 37b that converts the image signal into rOJ or "1" binary data, and an integrator 37c that adds up the number of binarized rOJ or "1" image data. The CPU 36 controls the first and second
The optical systems 1, 1, 1, and 2 are caused to prescan, read the image signal of the document G, calculate image processing conditions from the image signal, and output the result to the image processing circuit 35. The image processing circuit 35 generates image data for forming an electrostatic latent image from an image signal manually inputted from the CCD 12 (an image signal obtained by regular scanning) based on the image processing conditions, and transmits the image data to the laser diode 15. Output to.

Furthermore, when the CPU 36 enters the image signal reading position adjustment mode (this mode is set according to instructions from the operator), it generates image data for displaying the image signal reading position in the scanning direction, which will be described later, and The display device 40
Output to. 38 and 39 are a ROM and a RAM, respectively; the ROM 38 stores the processing program of the CPU 36, and the RAM 39 stores the processing program and data calculated by the CPU 36. 4o is the LCD or L provided on the operation panel of the copying machine main body 1 (see Figure 3).
This is a display device consisting of an ED.

Next, the display operation of the image signal reading position in the main scanning direction of the digital copying machine according to the present invention will be described.

When displaying the reading position of the image signal in the main scanning direction, first set the program mode of the CPU 36 to the image signal reading position adjustment mode, and, for example, display the test document GT which is divided into two colors as shown in FIG. As shown in FIG. 5, align the document edge Q of the test document G with the reference line Ro of the document table (see FIG. 3), and align the color-coded boundary line LM of the test document GT with the reference plate 4. The document is placed on the document table in alignment with the center display M, and reading scanning is performed.

The test document GT shown in FIG.
A white area 42 and a black area 43 are provided. The color-coded areas may be reversed to those shown in the figure, and the two colors may be chromatic as long as there is a clear difference in brightness. Also,
The length of the test document GT in the sub-scanning direction is an appropriate length that sufficiently covers the position Pi (see FIG. 5) where the image signal is read in the main scanning direction.

When a reading scan is performed, the first and second optical systems Ll and L2 move a preset distance and stop, and move in the main scanning direction at a predetermined position Pe in the sub-scanning direction, for example in the reading range a-a'. An image signal for one line is read by the CCD 12. Note that the reading range a-a is set shorter than the length 2l of the test document GT in the main scanning direction.

The image signals read by each sensor constituting the CCD 12 are subjected to a predetermined correction in the above-mentioned correction circuit 33, and then taken into the CPU 36 via the input selector 34.
For example, the white image signal is converted to "1" by the binarization circuit 37b.
”, the black image signal is converted to binary data of “0”. Then, the number of binarized data for each color is integrated by the integrator 37c, and the integration result is displayed on the display device 40. Note that the accumulated numbers of white and black binary data are equal to the number of pixels that receive white light and the number of pixels that receive black light among the number of pixels that constitute the CCD 12, respectively.

FIG. 6 is an example of displaying the numbers of white and black binarized data calculated from the image signals read in the reading range aa' shown in FIG. 5. In Figure 5, the reading range a
-a' indicates that the CCD 12 is in the main scanning direction.
This is the reading range when the center of the pixel column No. 2 and the center M of the document placement position are set to match. Furthermore, in this embodiment, the total number of pixels making up the CCD 12 is 50.
The case of 00 dots is shown. Therefore, the image signals of the white area and black area of the same length in the main scanning direction are transmitted to the CCD 12.
Therefore, the number of white and black dots displayed in the display area 44 of the display device 40 is the same, 2500 dots. If the mounting position of the CCD 12 is shifted toward the front of the copying machine with respect to the original stacking position specified on the reference plate 4, the reading range of the image signal becomes, for example, the reading range b-b' in FIG. In the read image signal, the black area is longer than the white area. As a result, the number of white and black dots displayed on the display device 40 is such that the number of black dots is greater than the number of white dots. This makes it possible to check the state of deviation of the image signal reading position in the main scanning direction. In FIG. 5, the test document G may be placed with the black and white areas reversed. In this case, in the display content in the reading range bb', the number of white dots is naturally greater than the number of black dots.

FIG. 7 is a display example in which the difference between the number of black dots and the number of white dots is displayed vector-wise in a bar graph 45 in the display area 44. In the figure, rFJ and rRJ indicate the front side and rear side of the copying machine, respectively, and the length of the displayed bar graph 45 is the difference N (=
It shows the absolute value of the number of black dots minus the number of white dots.

Further, if N>0, the bar graph 45 is displayed on the F side, and if N<Q, the bar graph 45 is displayed on the R side.

In the figure, a bar graph 45 is displayed on the F side, indicating that the number of black dots is greater than the number of white dots.
This shows that the attachment position of No. 2 is shifted toward the front side of the copying machine with respect to the document placement position designated by the reference plate 4. In addition,
In the display example shown in FIG. 7, if the black and white area of the test document G is placed in reverse, the display direction of the bar graph 45 will be reversed, so the placement position of the test document GT must be aligned with the display direction of the bar graph 45. There is. In this display example, since the amount and direction of deviation of the image signal reading position in the main scanning direction can be seen at a glance, the image signal reading position can be easily adjusted.

Now, in the above embodiment, the deviation of the image signal reading position in the main scanning direction is displayed, but the same display can be made in the sub-scanning direction as well. in this case,
As shown in FIG. 8, the white portion of the test original GT is placed on the reference plate 4 side and read scanning is performed to read image signals in a predetermined range c-c' in the sub-scanning direction. This predetermined range C1C' is set to twice the length l of the white portion of the test document G in the sub-scanning direction.

Note that the test original GT is not limited to the test original GT shown in FIG. 4, but may be one that is divided into two colors in the sub-scanning direction.

When reading scanning is performed, the first optical system L1 that has moved from the home position is detected by the photointerrupter 13, and reading of the image signal is started at this detection timing. Then, the predetermined range c-c' (distance 2I)
The image signal of is read and stored in the image memory 37a. Next, from among the image signals stored in the image memory 37a, the CPU 36 extracts, for example, the image signals on the position Pl line in the main scanning direction shown in FIG. white and black 2
After being converted into digitized data, the numbers of white and black binary data are respectively accumulated by an integrator 37c. and,
The integration results are displayed on the display device 40 in the display format shown in FIG. 6 above. Note that the image signal on the Pl' line may be obtained by selectively capturing the corresponding pixel signal on the sensor array of the CCD 12 when reading the image signal. In this case, the image signal is temporarily transferred to the image memory 37m.
Since the data is not stored in the memory, the above calculation process can be performed quickly.

In FIG. 8, the reading start timing of the image signal is at the reference line R.
．． Therefore, the C end and the C' end of the predetermined range c-c' are the reference line R, respectively.

coincides with the end of the test document G7, and the image signal of the entire test document GT is read.

Therefore, since the white area and the black area read in the predetermined range c-c' are the same, the numbers of white and black dots displayed on the display device 40 are the same.

However, if the reading timing of the image signal is earlier than the reference line Ro, the 2a portion of the contact glass 2 (
In other words, since the lower part of the reference plate 4 is white, the white area is longer than the black area within the reading range C-C', and the display device 40 shows that the number of white dots is less than the number of black dots. be larger than the number. On the other hand, if the image signal reading timing is slower than the reference line Ro, the reading range @c
-C', the black area is longer than the white area, and the number of black dots displayed on the display device 40 is greater than the number of white dots.

Further, the display format may be as shown in FIG.

In this case, the display rFJ indicates that the reading timing of the image signal is set to the reference line R. This indicates a slower case, indicating that the reinstallation position of the photo interrupter 13 is shifted in the sub-scanning direction. In addition, the display rRJ indicates that the reading timing of the image signal is set to the reference line R. This indicates that the position of the photo interrupter 13 is shifted toward the home position.

By the way, in the above embodiment, the test original GT, which is divided into two colors (black and white) at the center in the main scanning direction as shown in FIG. The image signal was read for each of the 9th
A test document GT' shown in 50 can also be used. The test document G in Figure 9 is a document divided into four areas at the center in the main scanning direction and the center in the sub-scanning direction, and one area and the other three areas are divided into two colors. It is.

In the figure, the shaded areas indicate black areas, and the other areas indicate white areas.

Align the document edge Q' of this test document GT' with the reference line Ro (see Figure 3) on the document table, and align the color-coded boundary line LM' of the test document GT' with the center mark M of the reference plate 4. If you want to display the reading position of the image signal in the main scanning direction, for example, read the image signal on the P2 line, and display the reading position of the image signal in the sub-scanning direction, for example, If the image signal on the P2 line is read, it is possible to read the image signal in each of the main scanning direction and the sub-scanning direction without replacing the test original, which is convenient.

As explained above, the difference in the numbers of white and black dots displayed on the display device 40 makes it possible to confirm the misalignment of the image signal reading position in each scanning direction, so the numbers of white and black dots are the same. By adjusting the mounting positions of the reference plate 4, the first optical system, the photointerrupter 13, or the CCD 12 in this way, it is possible to adjust the deviation of the image signal reading position in each scanning direction.

The deviation of the reading position of the image signal in the sub-scanning direction is performed by adjusting the mounting position of the reference plate 4, the placement position of the photo interrupter 13, etc. in the sub-scanning direction. Further, the deviation of the reading position of the image signal in the main scanning direction is performed by adjusting the relative position between the mounting position of the reference plate 4 and the mounting position of the CCD 12 in the main scanning direction.

To adjust the position of the reference plate 4, use the screw 41 as shown in FIG.
This is done by adjusting the fixing position of the reference plate 4 in the main scanning direction. Note that the position of the reference plate 4 can also be finely adjusted in the sub-scanning direction. Further, the position of the CCD 12 in the main scanning direction (direction D in the figure) is adjusted by operating the eccentric roller 55 shown in FIG.

FIG. 10 shows the unitized lens section 11 and CCD.
It is a perspective view of I2. In the figure, the lens portion l1 is
A lens force bar 1lb in which a lens lla is housed is fixed to a base plate 48.

Further, the CCD 12 is fixed at a predetermined position on a CCD mounting plate 49 (not visible in the figure), and the COD mounting plate 49 is mounted at a predetermined position on a height adjustment plate 50. The height adjustment plate 50 is attached to the position adjustment member 5 by a screw member (not shown).
The position adjusting member 51 is attached to the base plate 48 with screws 53 so that its position can be adjusted in the main scanning direction. The base plate 48, to which the lens portion l1 and the CCD 12 are attached, is attached to the support base 47 with screws 54, 54' and screws not shown so that its position can be adjusted in the sub-scanning direction (direction E in the figure). There is. The positional adjustment in the sub-scanning direction is performed by a screw 56 that passes through a hole provided at a proper location in the support base 47 and is screwed into a nut portion 48a that protrudes at a proper location on the pace plate 48.

That is, by rotating the screw 56, the base plate 4
8 moves in the sub-scanning direction with respect to the support table 47, and the positions of the entire lens section 11 and CCD 12 mounted on the base plate 48 in the sub-scanning direction are adjusted.

The height of the height adjustment plate 50 is adjusted using screws 52, 52' and springs 5 provided at both ends of the height adjustment plate 50.
2 a. This is done by a height adjustment mechanism consisting of 5 2 a'. That is, by rotating the screw 52 or the screw 52', the heights of both ends of the height adjusting plate 50 are respectively adjusted. Further, the position adjustment of the position adjustment member 51 in the main scanning direction is performed by an eccentric roller 55.

By rotating the eccentric roller 55, the position adjustment member 51
moves in the D direction, that is, the main scanning direction, and the CCD 12
The position in the main scanning direction is adjusted.

〔Effect of the invention〕

As explained above, according to the present invention, the image signals of a test document divided into two colors are read in a predetermined range in the scanning direction, the number of COD pixels that have received each color from the image signals is integrated, and Since data based on the integration results is displayed on the display device installed in the copying machine, the deviation of the image signal reading position in the scanning direction can be confirmed, and the document placement position can be determined while checking the display contents. By adjusting the specified mounting position of the reference plate, COD mounting position, photo interrupter mounting position, etc., it is possible to easily and accurately adjust the image signal reading position in the main scanning direction and sub-scanning direction. . Further, since no special measuring equipment is required, the image signal reading position can be adjusted easily and in a short time after the above-mentioned members are replaced or repaired in the field.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of an image reading position display device in an image forming apparatus according to the present invention, and FIG. 2 is a diagram showing the overall configuration of an image forming apparatus having an image reading position display device according to the present invention. 3 is a top perspective view of the image forming apparatus according to the present invention, FIG. 4 is a diagram showing a test original, and FIG. 5 is a diagram showing a test original placed on a document mounting table when reading an image signal in the main scanning direction. 6 is a diagram showing a first display example displayed on a display device, FIG. 7 is a diagram showing a second display example displayed on a display device, and FIG. 8 is an image in the sub-scanning direction. FIG. 9 is a diagram showing a test document placed on a document table when reading a signal, FIG. 9 is a diagram showing another example of a test document, and FIG. 10 is a perspective view showing a unit to which a lens section and a CCD are attached. be. 1... Copying machine body, 4... Reference plate, 5... Reflector, 6... Halogen lamp (light source), 7.9.10...
・Reflector, 8... Partition plate, 11... Lens part, 12
...CCD (image data reading device), 13.14...
・Photo interlayer, 15... Laser diode (image data output device rI1), 33... Correction circuit, 3
4...Input selector, 36...CPU (microcomputer), 37a...image memory, 37b...
・Binarization circuit, 37c...Integrator, 38-ROM,
39-RAM, 40... Display device, 41... Screw,
44... Display area, 45... Bar graph, 47...
Support stand, 48...Base plate, 49...CCD mounting plate, 5o...Height adjustment plate, 5l...Position adjustment member, 5
5... Eccentric roller, G↑. GT: Test manuscript.

Claims (1)

[Claims] 1. In an image forming apparatus that generates image data for forming a latent image from an image signal of a document read by an imaging means and outputs the image data to a photoreceptor to form an image, the imaging means generates image data in a predetermined scanning direction. a binarizing means for binarizing each image signal of the test document whose range has been read and which is color-coded into two colors in the scanning direction;
An image reading position in an image forming apparatus, characterized in that the image forming apparatus comprises an integrating means for respectively integrating the number of data of the value and the number of data of the second value, and a display means for displaying the data obtained based on the integration result. display device.