JP2919879B2 - Focus state display device of image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to a focus state display apparatus of an image forming apparatus capable of monitoring a focus state using a read image signal of a document. .

[Conventional technology]

For example, in an image forming apparatus such as a copying machine, image information (image information for forming an electrostatic latent image on a photoreceptor) obtained by reflected light of light applied to a document surface is spread over the entire image forming area. In order to obtain under good focus,
2. Description of the Related Art At the time of product manufacture, repair, maintenance and inspection, optical and electrical adjustments of an optical system including a reflecting mirror and a lens unit and an image reading unit formed by a CCD or the like are performed. Conventionally, high-speed oscilloscopes, logic analyzers, D / A converters, etc. have been used for this type of optical and electrical adjustment. Adjustments have been made.

[Problems to be solved by the invention]

By the way, usually, in the manufacturing department, since the respective measuring instruments such as the high-speed oscilloscope and the logic analyzer are expensive, it is desired in the manufacturing department that the focus adjustment can be performed by using an inexpensive and simple measuring instrument instead of them. . In the field maintenance, it is not easy to carry out the measurement equipment due to the widening of the field, the limitation of the number of the measurement equipment, and the maintenance is often performed without using the measurement equipment. For this reason, even if the optical system mirror, lens, CCD board, etc. can be replaced, accurate focus re-adjustment cannot be performed, and sufficient maintenance is difficult.

The present invention has been made in view of the above problems, and has as its object to provide a focus state display device of an image forming apparatus that can easily monitor image information for focus adjustment.

[Means for solving the problem]

A focus state display device of an image forming apparatus according to the present invention is configured to generate image data for forming a latent image from an image signal of a document read by an imaging unit, and output the image data to a photoconductor to form an image. In the apparatus, an image signal of at least one scanning line is read from a test pattern original having a striped pattern by the imaging means, and an image signal of the same level is extracted from the read image signal. Means, integration means for integrating the number of image signals of the same level for each level, and display means for displaying the integration result in a histogram.

According to a second aspect of the present invention, the halftone level is extracted from the read image signal, the number of image signals of the halftone level is integrated for each reading area, and the integration result is displayed as a histogram for each reading area. I made it.

[Action]

In the focus state display device of the image forming apparatus configured as described above, the optical system is scanned, and at least one scanning line is read from the image signal of the test pattern original on which the predetermined pattern is drawn by the imaging unit. Image signals of the same level are extracted from the read image signals, and the same level and the number of image signals are integrated for each level. Then, the integrated result is displayed as a histogram.

According to the second aspect, a halftone level is extracted from the read image signal, and the extracted halftone level is integrated for each reading area. Then, the integrated result is displayed as a histogram.

Embodiment FIG. 2 is a side sectional view showing the overall configuration of a digital copying machine (image forming apparatus) having a focus state display function according to the present invention. An original mounting table is formed on the upper surface of the copying machine main body 1 by a contact glass 2, and an original presser 3 for pressing an original G placed opposite to the original mounting table is provided. An image data reading unit including a first optical system L ₁ , a second optical system L ₂ , a lens unit 9, and a CCD 10 (imaging device) is disposed in an upper part in the copying machine main body 1. The first optical system L ₁ is mainly reflector 4 consists halogen lamp 5 and a reflecting mirror 6, etc., the second optical system L ₂ is composed primarily reflector 7 and 8, the drive (not shown) The mechanism reciprocates along the document surface. In the image data reading unit, the original G is irradiated with light by the halogen lamp 5 and the reflected light is guided to the CCD 10 via the reflecting mirrors 6, 7, 8 and the lens unit 9 to form an image on the imaging surface of the CCD 10. The image data of the original, that is, the light / dark level of the reflected light is captured by the CCD 10 and stored in a storage device (not shown).

A laser diode 11 is placed in a proper place in the copying machine main body 1.
(Image data output device), polygon mirror 12 and reflecting mirror
An image data output unit 13 is provided.
In the image data output unit, image data generated by an image processing circuit described later is modulated into laser light by a laser diode 11 and output to a polygon mirror 12, and line scanning (main scanning) is performed by rotation of the polygon mirror 12. Thereafter, the light is guided to the photosensitive drum 14 via the reflecting mirror 13.

An image forming means including a transfer mechanism, a paper feed mechanism, and a paper discharge mechanism is disposed at a proper lower portion in the copying machine body 1. The transfer mechanism includes a photosensitive drum 14, a charging device 15, a phenomenon device 16, a transfer device 17, a separation device 18, a cleaning device 19, and the like. After the photosensitive drum 14 charged by the charging device 15 is formed with an electrostatic latent image of the image data output from the image data output unit, the image data is visualized by the developing device 16, The image data visualized by the transfer device 17 is transferred to a sheet. After the transfer, the photosensitive drum is separated by the separating device 18.
After the transfer paper is separated from 14, the cleaning device
19 removes the toner remaining on the drum surface. The paper feed mechanism includes a paper feed cassette 20, a paper feed roller 21, a paper feed guide 22, and a transport roller pair 23 provided at the bottom of the copying machine main body 1.
And a paper feed cassette 20 by the paper feed roller 21.
Paper fed from the paper feed guide 22,
The toner is fed to the photosensitive drum 14 by 23. The discharge mechanism includes a transport belt 24, a fixing unit 25, and a discharge roller pair 26. The sheet transferred by the transfer device 17 is transported from the transport belt 24 to the fixing unit 25, and is fixed by the fixing unit 25. After that, the sheet is discharged to a discharge tray 27 by a pair of discharge rollers 26.

FIG. 1 shows a system configuration diagram relating to a focus state display according to the present invention in the digital copying machine. 2, the same members as those shown in FIG. 2 are denoted by the same reference numerals. An AVR unit 28 controls the amount of light emitted from the halogen lamp 5. The AVR unit 28 controls the light emission amount of the halogen lamp 5 so that the light amount is set by a volume not shown. Reference numeral 29 denotes a correction circuit for correcting an image signal (image level) picked up by the CCD 10, for example, due to variations in image signals due to variations in light receiving sensitivity of each element constituting the CCD 10 and variations in brightness of the lens unit 9. A deviation of the image signal is corrected, and a light amount error is corrected. Reference numeral 30 denotes an input selector for selecting a capture destination of the image signal. The input selector 30 transfers the image signal to a subsequent image processing circuit 31 or an image memory in the CPU 32 according to a command signal from a microcomputer 32 (hereinafter, referred to as a CPU). Selectively output.

31 is a photosensitive drum 1 from an image signal input from the CCD 10
5 is an image processing circuit for generating image data for forming an electrostatic latent image. Reference numeral 32 denotes a CPU for centrally controlling the copying operation of the copying machine, and has a built-in image memory 32a for storing image signals input from the CCD 10. The CPU 32 pre-scans the first and second optical systems L ₁ and L ₂ during the copying operation, works on the image signal of the original, calculates the image processing conditions from the image signal, and outputs it to the image processing circuit 31. The image processing circuit 31 generates image data for forming an electrostatic latent image based on image processing conditions input from the CPU 32 by using an image signal input from the CCD 10 (image signal obtained by normal scanning), and outputs the image data. Is output to the laser diode 11. Further, when the CPU 32 enters the focus adjustment mode (this mode is set by an instruction from the operator), the CPU 32 generates image data for displaying a histogram described later and outputs the image data to the display unit 35.

33 and 34 are a ROM and a RAM, respectively.
The RAM 34 stores a processing program and data calculated by the CPU 32. 35 is an LCD or LED provided on the operation panel of the copying machine,
This is a panel-shaped display unit capable of displaying a histogram (see FIGS. 6 and 7) as described later. Reference numeral 36 denotes an external input device including a keyboard or the like, which is selected when shifting to a focus adjustment mode described later. When the focus adjustment mode is performed in the arrangement direction of the CCD 10, that is, in the main scanning direction, as described later, the main scanning is performed at a predetermined sub-scanning position. When scanning is performed in the moving direction of the optical systems L ₁ and L ₂ , that is, in the sub scanning direction, sub scanning is performed at a predetermined main scanning position (element at a predetermined position of the CCD 10). This keyboard 36 is provided on an operation panel of the copying machine main body.

The amount of data that can be read by the CCD 10 and the image memory 3
If the capacity of 2a and the number of pixels of the display unit 35 are different, CCD1
At the time of reading from 0 to the image memory 32a, or at the time of reading from the image memory 32a to the display unit 35, data editing, for example, data thinning processing is performed.

Next, an operation when the focus state of the image forming apparatus according to the present invention is displayed as a histogram will be described. In this embodiment, it is assumed that scanning in the focus adjustment mode is performed in the main scanning direction.

First, as shown in FIG. 3, for example, a Munsell value N9.5 (white) and a Munsell value in which horizontal stripes
An original having a brightness of N1.0 (black) (hereinafter, referred to as a text pattern original) is placed on an original mounting table of a copying machine, and a copy operation in a focus adjustment mode is started. The optical system stops after moving to the predetermined position in the sub-scanning direction as described above, and performs scanning in the main scanning direction at this position to read one line of the image signal of the test pattern document.
After the image signal captured by the CCD 10 is subjected to a predetermined correction by the above-described correction circuit 29, the signal is input via the input selector 30.
The image is stored in the image memory 32a in the CPU 32.

FIG. 4 and FIG. 5 show the contents of the image signal captured by the CCD 10, in which black and white levels corresponding to the horizontal stripe pattern of the test pattern document appear at predetermined intervals. In the figure, the horizontal axis represents one line in the main scanning direction, and the vertical axis represents the level of the image signal. FIG. 4 shows a state in which focus is not achieved, and FIG. 5 shows a state in which focus is achieved.

That is, in the case of FIG. 4 which is out of focus, since the image is out of focus, the test pattern document has a light intermediate color (halftone) in which a white portion is slightly mixed with black, and conversely, a black portion is slightly mixed in white. As a dark neutral state
Read by CCD10. For this reason, the image signal read by the CCD 10 is recognized as a stripe pattern composed of a light intermediate color and a dark intermediate color. On the other hand, in the case of FIG. 5 which is in focus, the test pattern document is read by the CCD 10 as being divided into a white portion and a black portion. For this reason, CCD10
Is read as a stripe pattern composed of white and black with few intermediate colors.

Subsequently, the CPU 32 sequentially scans each cell of the CCD 10 and
Are sequentially read from the first cell. Then, data of the same level is extracted from the level data, and the number of data is integrated for each level. Thereafter, a histogram having the horizontal axis as the level and the vertical axis as the number of data is displayed on the display unit 35.

6 and 7 are diagrams showing a histogram display form on the display unit 35. FIG. 6 shows a histogram when the subject is out of focus, and FIG. 7 shows a histogram when the subject is in focus. Is shown.

That is, in the case of FIG. 6 which is out of focus, as described above, since the image signal read by the CCD 10 is composed of a light intermediate color and a dark intermediate color, the level data read from each cell of the CCD 10 is represented by a histogram. They will gather near the middle. On the other hand, in the case of FIG. 7 in which the image is in focus, as described above, since the image signal is made up of white and black with few intermediate colors, the level data is collected at both ends of the histogram.

Therefore, the quality of the focus state in the main scanning direction can be determined based on the distribution state of the histogram display. That is, it is possible to easily adjust and confirm the focus in the main scanning direction.

Next, another embodiment of the focus state display of the image forming apparatus according to the present invention will be described with reference to FIG.

In this embodiment, the CPU 32 divides the cells of one line of the CCD 10 into, for example, three areas, and outputs the same intermediate color (halftone) from the level data taken into each cell of each area.
Are extracted, and the number of data is integrated for each area. Thereafter, the data is displayed on the histogram display unit 35 in which the horizontal axis represents the area and the vertical axis represents the number of data.

That is, it is possible to easily determine the focus shift in each area in the scanning direction (left-right direction) from the variation in the number of data in each area. Further, as described above, the larger the number of data of the intermediate color level, the more out of focus. Therefore, when the number of data in all areas is minimized,
You are in focus.

Next, another embodiment of the focus state display will be described.

In this embodiment, image data is obtained by scanning the optical system in the sub-scanning direction. That is, CCD10
The image signal is taken in the predetermined cell. As shown in FIG. 9, a test pattern original having a vertical stripe pattern (a horizontal stripe pattern can be used vertically) can be used. In this embodiment, the quality of the focus state in the sub-scanning direction can be determined based on the distribution state of the histogram display. That is, it is possible to easily adjust and confirm the focus in the sub-scanning direction.

Next, a mechanism related to focus adjustment of the image data reading unit will be described.

FIG. 10 is a perspective view showing an adjusting mechanism of each unit of the image data reading unit. 2, the same members as those shown in FIG. 2 are denoted by the same reference numerals. The xyz axis and the angle ψ are coordinates for indicating the adjustment direction of each member.

The focus state is determined by the relationship between the optical path length until the light reflected by the document reaches the lens unit 9 and the optical path length from the lens unit 9 to the CCD 10. Therefore, the adjustment of the focus state is performed by adjusting the mounting state of the first optical system L ₁ , the second optical system L ₂ , the lens unit 9 and the CCD 10.

41 The first movable frame member first optical system L ₁ is mounted, 42 is a second first moving frame optical system L ₂ is attached. First
The moving frame 41 and the second moving frame 42 are slidably mounted on guide rails (not shown), and reciprocate on the guide rails by winding the wires W, W 'stretched on both sides thereof. It has been made to be. The optical path length from the first optical system L ₁ to the second lens 9 parts through the optical system L ₂ is must always be maintained at a predetermined length, and both need to hold the main scanning direction and parallel state There is.

When the optical path length is set to a predetermined length, the mounting positions of the reflecting mirror 6 (see FIG. 2) and the reflecting mirrors 7 and 8 are adjusted. Adjustment of the mounting position of the first optical system L ₁ and the second optical system L ₂ for this purpose is performed by fixing the positions of the wires W and W ′ to which the fixing members 41 a and 41 a ′ of the first moving frame 41 are fixed. By adjusting the positions fixed to the copier body side by the members 40 and 40 ', respectively, and adjusting the wire length and tension between the first moving frame 41 and the second moving frame 42 of both wires. Done. Also,
Adjustment of the parallelism of the xy plane of the first optical system L ₁ and the second optical system L ₂ is fixed member 41a of the first moving frame 41, 41a 'wire is fixed to the W, W' position of This is performed by adjusting one of the position and the position fixed to the copying machine main body side by the fixing members 40 and 40 '.

Furthermore, since the first optical system L ₁ and the second optical system L ₂ changes the optical path length between the non-parallel with the xz plane first optical system L ₁ and the second optical system L ₂ is the location, from which May also need to be adjusted. This adjustment is performed by a height adjusting mechanism provided at one end of the second moving frame 42. That is, one end of the support base 42a of the second moving frame 42 is attached to the support member 42b by a screw 55 via a spring 55a so as to be adjustable in height, and the other end is directly mounted on the guide rail. It has a structure. Therefore, parallelism in the xz plane of the first optical system L ₁ and the second optical system L ₂ by adjusting the height of the one end of the support base 42a by the screw 55 (so-called, non-parallel by torsion) You can make adjustments.

The lens unit 9 is a lens cover fixed to the base plate 44
A lens 9a is configured to be position-adjustable in the y direction within 9b. That is, the arrangement position of the lens 9a is adjusted in the y direction by rotating the screw 48. Thereby, the focus and the same magnification of the image on the CCD 10 can be adjusted.

Further, the optical path length between the first optical system L ₁ and the lens portion 9 can be changed by adjusting the base table 44 to be described later.

Reference numeral 43 denotes a support base on which the lens unit 9 and the CCD 10 are mounted. The lens unit 9 and the CCD 10 are unitized by the support base 43, and are mounted at predetermined positions in the copying machine. Further, the lens unit 9 and the CCD 10 are mounted on a support 43 via a base plate 44. Base plate 44 is screw 5
A long hole in the y direction is formed at each screwing position of the screws 2, 52 'and a screw (not shown), and is attached to the support base 43 so that the position can be adjusted in the y direction. This position adjustment is performed by a screw 54 that is screwed into a nut portion 44a protruding from a proper position of the base plate 44 through a hole provided at a proper position of the support base 43. That is, by rotating the screw 54, the base plate 44 moves in the y direction with respect to the support table 43, and the position adjustment of the lens unit 9 and the CCD 10 mounted on the base plate 44 in the y direction is performed.

Mounting position and angle of CCD 10 with respect to lens unit 9
The adjustment is performed by the following mechanism.

46 and 47 are a position adjusting member and a height adjusting plate of the CCD 10, respectively. The CCD 10 is fixed at a predetermined position on a CCD mounting plate 45, and the CCD mounting plate 45 is mounted on a predetermined position on a height adjustment plate 46. The height adjusting plate 46 to which the CCD mounting plate 45 is attached is a position adjusting member using a screw member (not shown).
The height is adjustable to 47. This height adjustment is performed by screws 51, 5 provided at both ends of the upper part of the height adjustment plate 46.
This is performed by a height adjusting mechanism composed of 1 'and springs 51a, 51a'. That is, both upper ends of the height adjustment plate 46 are
It is screwed to the position adjusting member 47 by screws 51, 51 'via springs 51a, 51a'. By rotating the screw 51 or the screw 51 'and adjusting the height of both ends of the height adjusting plate 46, the inclination of the CCD 10 attached to the height adjusting plate 46 in the xz plane can be adjusted.

The position adjusting member 47 to which the CCD mounting plate 45 and the height adjusting plate 46 are mounted has an elongated hole in the x direction at a screwed portion,
It is attached to the base plate 44 by screws 53 so that the position can be adjusted in the x and ψ directions. These adjustments are
This is performed by an eccentric roller 49 for position adjustment in the x direction and an eccentric roller 50 for angle adjustment in the の direction provided on the position adjusting member 47. That is, by rotating the eccentric roller 49, the position adjusting member 47 moves in the x direction and the position of the CCD 10 in the x direction is adjusted, and by rotating the eccentric roller 50, the position adjusting member 47 is screwed by the screw 53. The center of the CCD 10 is moved in the ψ direction to adjust the position of the CCD 10 in the ψ direction.

When the focus is not good, the first and second optical systems L ₁ , L ₂ ,
The focus can be easily adjusted by adjusting the respective adjustment mechanisms of L ₂ , lens unit 9 and CCD 10.

In the above embodiment, an image signal for one line in the scanning direction is taken in. However, a plurality of scanning lines may be read and a plurality of histograms may be displayed. Alternatively, the above processing can be performed by editing signals of a plurality of scanning lines into signals of one scanning line.

〔The invention's effect〕

As described above, according to the present invention, the in-focus display device is provided in the copying machine main body, and the read image signals are integrated for each same level and displayed as a histogram.
Focus adjustment and confirmation can be easily performed without using a special measuring device. Further, since no measuring equipment is required, sufficient maintenance can be performed easily and in a short time even in the field.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of the present invention, FIG. 2 is a side sectional view showing the entire configuration of the present invention, FIG. 3 is a document (test pattern document) in which horizontal stripes are drawn at regular intervals, FIG. Fifth
FIGS. 6A and 6B are diagrams showing the contents of the image captured by the CCD. FIGS.
The figure shows another example of the histogram display mode, and FIG.
FIG. 10 is a perspective view showing a document on which a vertical stripe pattern is drawn, and FIG. 10 is a perspective view showing an adjusting mechanism of each unit of the image data reading unit. 1. Copy machine body, 4. Reflector umbrella, 5. Halogen lamp (light source), 6, 7, 8 Reflector mirror, 9 Lens part, 10
... CCD (image data reader), 11 ... Laser diode (image data output device), 29 ... Correction circuit, 30 ... Input selector, 32 ... CPU (microcomputer), 32a
…… Image memory, 33… ROM, 34… RAM, 35 …… Display unit, 36… Keyboard, L ₁ … First optical system, L ₂ …… Second
Optical system.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Uehira, 1-2-28 Tamazo, Chuo-ku, Osaka-shi, Osaka Prefecture Inside Mita Kogyo Co., Ltd. (72) Yoshiyuki Fujiwara 1-chome, Tamazuki, Chuo-ku, Osaka-shi, Osaka No. 28 No. 28 Mita Kogyo Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) H04N 1/00-1/00 108 H04N 1/04-1/207

Claims (2)

(57) [Claims] An image forming apparatus for generating image data for forming a latent image from an image signal of a document read by an image pickup means and outputting the image data to a photosensitive member to form an image.
Extracting means for reading an image signal of at least one scanning line from a test pattern original having a striped pattern by the imaging means, and extracting an image signal of the same level from the read image signals; A focus state display device for an image forming apparatus, comprising: an integrating means for integrating the number of image signals of the same level for each level; and a display means for displaying the integrated result in a histogram. 2. The method according to claim 2, wherein a halftone level is extracted from the read image signal, the number of the halftone level image signals is integrated for each reading area, and the integration result is displayed in a histogram for each reading area. 2. The focus state display device for an image forming apparatus according to claim 1, wherein: