JP3346812B2 - Color image forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus such as a digital color copying machine and a color printer.

[0002]

2. Description of the Related Art As shown in FIG. 28, for example, a test pattern of a conventional color image forming apparatus has a pattern of each color overlapping the same portion. Are overlapped in the image synthesizing section (photoconductor, intermediate transfer belt). That is, a pattern in which the patterns are on the same line and the patterns of the respective colors are overlapped is generated.

Another conventional test pattern is a parallel pattern in which patterns of respective colors are arranged on the same line (FIG. 27). That is, the patterns are not on the same line,
It is on a parallel line.

[0004]

However, according to the prior art, in the former case, as described above, when there is no positional shift, images of different colors are formed overlapping in the image combining section. However, at this time, there is a drawback that the color formation of each other is blurred due to the color overlap in the image forming process, so that it is difficult to confirm the degree of overlap of the test patterns.

In the latter case, the test pattern is a parallel pattern in which the patterns of the respective colors are arranged on the same line. In this case, it is necessary to measure the pattern interval for the amount of positional deviation, which makes it difficult to check the pattern. is there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color image forming apparatus capable of reducing the time and cost for adjusting the positional deviation.

[0007]

To achieve the above object, the present invention provides a color image forming apparatus for forming a color image by synthesizing images of different colors obtained by a plurality of image forming steps. a memory storing different patterns for each color, the so as not different color patterns stored in the memory not overlap on the same straight line, and each color endpoint of
And a control means for performing control so as to be close to each other.

[0008]

According to the above-mentioned means, in an image generating apparatus for forming a color image (including two colors and full colors) by combining images of different colors obtained in a plurality of image forming steps, the alignment of each color is adjusted. A test pattern is formed for each monitor color in a test pattern generator for monitoring, and the positional deviation (main scanning direction, sub-scanning direction, parallelism) of each color is confirmed and corrected based on the result of synthesizing the test patterns. A test pattern formed at the time of adjusting a plurality of writing positions is easy to recognize without bleeding, and a position shift can be visually confirmed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory view showing a schematic configuration of a color image forming apparatus according to the present invention, FIG. 2 is an explanatory view showing an enlarged view of a photosensitive member and an intermediate transfer belt, and FIG. 3 is a block diagram of the first embodiment. 4 is a block diagram of a pattern generator of the first embodiment, FIG. 5 is a block diagram of an LD driver circuit, FIG. 6 is an explanatory diagram showing font data stored in a font ROM 74, and FIG. 7 shows the contents of a text ROM. FIG. 8 is an explanatory diagram showing the output result of the text ROM, FIG. 9 is an explanatory diagram showing the contents of the text ROM, FIG. 10 is an explanatory diagram showing the output result of the text ROM, FIG.
FIG. 4 is an explanatory diagram showing a time chart of this method.

An example of a color image forming apparatus for forming a color image by synthesizing images of different colors obtained by a plurality of image forming steps will be described with reference materials.

The image generating method of the color image generating apparatus of the present invention is roughly classified into two types.

The first embodiment is a first system in which the image forming process for a plurality of colors is performed after the image forming process for the first color is completed, and then the image forming process for the next color is performed. The second embodiment is the second system, in which the second color image is formed at the timing when only the distance difference between the writing positions is delayed during the first color image forming process.

The first embodiment describes a full-color copying machine for synthesizing an image on an intermediate transfer belt, and each color co-formation uses a scanning optical system using the same LD (laser diode).

FIG. 1 is an explanatory diagram showing a schematic configuration of a color image forming apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing an enlarged view around a photosensitive member and an intermediate transfer belt.

A color image reading apparatus (hereinafter, referred to as a color scanner) 101 forms an image of an original 103 on a color sensor 107 via an illumination lamp 104, a mirror group 105, and a lens 106, and outputs a color image of the original. The image information is read, for example, for each color separation of blue, green, and red, and is converted into an electric image signal.

In this example, the color sensor 107 is B,
It is composed of G and R color separation means and a photoelectric conversion element such as a CCD, and performs simultaneous reading of three colors.

Based on the B, G, and R color separation image signal intensity levels obtained by the color scanner 101, a color conversion process is performed by an image processing unit (not shown).
k (hereinafter referred to as Bk), Cyan (same as above, C), Magenta
(Same, M) and Yellow (same, Y) color image data are obtained.

This is converted into a color image by a color image recording apparatus (hereinafter, referred to as a color printer) 102 described below.
Visualization of k, C, M, and Y is performed to obtain a final color copy.

The operation of the color scanner 101 for obtaining the image data of Bk, C, M, and Y is as shown in FIG. The mirror optical system scans the original in the direction of the left arrow, and obtains one color image data for each scan.

By repeating this operation a total of four times, sequential four-color image data is obtained. Each time, the color printer 102 sequentially superimposes the images and superimposes them to form a four-color full-color image.

Next, an outline of the color printer 102 will be described. The writing optical unit 108 converts the color image data from the color scanner 101 into an optical signal, performs optical writing corresponding to the original image, and forms an electrostatic replacement image on the photosensitive drum 109. The unit 108
Laser 108-1 and its light emission drive control unit (not shown),
Polygon mirror 108-2 and its rotation motor 108-3,
It is composed of an f / θ lens 108-4, a reflection mirror 108-5, and the like.

The photosensitive drum 109 rotates in the counterclockwise direction as shown by the arrow. Around the photosensitive drum 109, a photosensitive member cleaning unit (including a pre-cleaning neutralizer) 110, a neutralizing lamp 111, a charger 112, and a potential sensor 113 are provided. , B
k developing device 114, C developing device 115, M developing device 116, Y
A developing device 117, a development density pattern detector 118, an intermediate transfer belt 119, and the like are provided.

Each of the developing units rotates a developing sleeve (114-1, 115-1, 116-1, 117-117) which rotates by contacting a spike of developer with the surface of the photoreceptor 109 in order to develop an electrostatic replacement image.
1) and a developing paddle (114-2, 115-2, 116-2, 117-) rotating to pump up and agitate the developer.
2) and a toner concentration detection sensor (114-
3, 115-3, 116-3, 117-3).

Now, in the standby state, all four developing units
The agent on the developing sleeve is in the state of cutting off (development inoperative), but the order of the developing operation (color image forming order)
An example of Bk, C, M, and Y will be described below (however, the image forming order is not limited to this).

When the copying operation is started, reading of Bk image data is started at a predetermined timing by the color scanner 101, and light writing / latent image formation by laser light is started based on the image data (hereinafter referred to as Bk image data). Is referred to as a Bk latent image, and the same applies to C, M, and Y).

In order to enable development from the front end of the Bk latent image, before the front end of the latent image reaches the developing position of the Bk developing unit 114, the developing sleeve 114-1 is started to rotate and the spike of the agent is started. Then, the Bk latent image is developed with Bk toner.

Thereafter, the developing operation of the Bk latent image area is continued, but when the rear end of the latent image passes the Bk developing position,
The cutting of the agent on the Bk developing sleeve 114-1 is promptly performed, and the developing operation is stopped. This is at least the following C
This is completed before the leading end of the C latent image based on the image data arrives.

The rotation is performed by switching the rotation direction of the ear-cut developing sleeve 114-1 in a direction opposite to that during the developing operation.

The Bk toner image formed on the photosensitive member 109 is transferred onto the surface of the intermediate transfer belt 119 driven at a constant speed with the photosensitive member 109 (hereinafter, the toner image is transferred from the photosensitive member 109 to the intermediate transfer belt 119). Transfer is called belt transfer). This belt transfer is performed while the photoconductor 109 and the intermediate transfer belt 119 are in contact with each other.
This is performed by applying a predetermined bias voltage to 0.

On the intermediate transfer belt 119, Bk, C, M, and Y toner images sequentially formed on the photosensitive member 109 are formed.
A four-color superimposed belt transfer image is formed by sequentially aligning the belt on the same surface, and thereafter, batch transfer is performed on transfer paper. The configuration and operation of the intermediate transfer belt unit will be described later.

On the photosensitive member 109 side, the process proceeds to the step C after the step Bk. At a predetermined timing, the reading of the C image data by the color scanner 101 starts, and the formation of the C latent image is performed by writing the laser light based on the image data. Do.

The C developing device 115 moves its developing position to
After passing at the rear end of the previous Bk latent image and before the leading end of the C latent image arrives, the rotation of the developing sleeve 115-1 is started to spike the agent, and the C latent image is developed with the C toner. I do. Since then
The development of the C latent image area is continued, but when the rear end of the latent image has passed, the C developing sleeve 1
15-1. This is also completed before the leading end of the next M latent image arrives.

In the steps M and Y, the operations of reading image data, forming a latent image, and developing are the same as those in the above-described steps Bk and C, and thus the description thereof is omitted.

Next, the intermediate transfer belt unit will be described. The intermediate transfer belt 119 includes a driving roller 121,
It is stretched around the belt transfer bias roller 120 and the driven roller group, and is driven and controlled by a drive motor (not shown) as described later.

The belt cleaning unit 122 includes a brush roller 122-1, a rubber blade 122-2, a mechanism 122-3 for contacting and separating from the belt, and the like.
After the Bk image of the color is transferred to the belt, the belt is separated from the belt surface by the contact / separation mechanism 122-3 during the belt transfer of the second, third, and fourth colors.

The paper transfer unit 123 includes a paper transfer bias roller 123-1 and a roller cleaning blade 123.
-2 and a mechanism 123-3 for contacting and separating from the belt.

The bias roller 123-1 is normally separated from the surface of the belt 119.
When the superimposed images of the four colors formed on the nine sides are collectively transferred to the transfer paper 124, they are pressed by the contact / separation mechanism 123-3 in a timely manner, and a predetermined bias voltage is applied to the rollers 123-1 so that the paper 12 Transfer to

Note that the transfer paper 124 is
5. The leading end of the four-color superimposed image on the surface of the intermediate transfer belt is fed by the registration roller 126 at the timing of reaching the paper transfer position.

Now, the manner of movement of the intermediate transfer belt 119 is as follows.
After the belt transfer of the Bk toner image of the first color has been completed to the rear end, the following three operation methods are conceivable. ) Operate by a combination of efficient methods.

1) Constant speed dwelling method After the Bk toner image is transferred to the belt, the dwelling is continued at a constant speed.

When the front end position of the Bk image on the surface of the belt 119 reaches the belt transfer position at the contact portion with the photoconductor 109 again, the front end portion of the next C toner image is just on the photoconductor 109 side. The image is formed in a timely manner so that

As a result, the C image is transferred onto the intermediate transfer belt 119 in a state of being accurately aligned with the Bk image.

Thereafter, by the same operation, the process proceeds to the M and Y image processes, and a belt transfer image of four-color superposition is obtained.

Following the fourth color Y toner image belt transfer step, the fourth color superimposed toner image on the belt surface is collectively transferred onto the transfer paper 124 as described above, while moving.

2) Skip dwelling method When the belt transfer of the Bk toner image is completed, the photosensitive member 10
The belt 119 is separated from the nine surfaces, skipped at high speed in the forward movement direction, and returned to the original forward movement speed after moving a predetermined amount.

Thereafter, the belt 1 is again attached to the photosensitive member 109.
19 is contacted.

When the front end position of the Bk image on the belt 119 reaches the belt transfer position again, the photosensitive member 1
On the 09 side, an image is formed at a timing such that the leading end of the next C toner image is exactly at that position.

As a result, the C image is transferred to the Bk image while being accurately aligned with and superposed on the Bk image.

Thereafter, by the same operation, the process proceeds to the M and Y image processes, and a belt transfer image of four-color superposition is obtained.

Following the step of transferring the Y toner image belt for the fourth color, the four-color image on the belt 119 surface is
The color superimposed toner image is collectively transferred to the transfer paper 124.

3) Home return (quick turn) method When the belt transfer of the Bk image is completed, the belt 119 is separated from the surface of the photoreceptor 109, and the forward movement is stopped, and at the same time, the belt 119 is turned at a high speed in the reverse direction.

In the return, the front end position of the Bk image on the surface of the belt 119 passes through a position equivalent to the belt transfer in the reverse direction, and after moving a predetermined distance, stops and enters a standby state.

Next, when the leading end of the C toner image on the photosensitive member 109 reaches a predetermined position before the belt transfer position, the intermediate transfer belt 119 is started again in the dwelling direction.

Further, the belt 119 is brought into contact with the surface of the photosensitive member 109 again.

Also in this case, the C image is transferred to the belt 119 under the condition that the C image accurately overlaps the Bk image on the belt 119 surface.

Thereafter, by the same operation, the process proceeds to the M and Y image processes, and a belt transfer image of four-color superposition is obtained.

Subsequent to the belt transfer process of the fourth color Y toner image, the toner is moved at the same speed without returning,
The four-color superimposed toner image on the belt 119 is collectively transferred to the transfer paper 124.

The transfer paper 124 on which the four-color superposed toner image has been collectively transferred from the intermediate transfer belt surface is transferred to the paper transport unit 1.
The fixing roller 128-1 and the pressure roller 128-2 conveyed to the fixing device 128 at 27 and controlled to a predetermined temperature.
Then, the toner image is fused and fixed, and is carried out to the copy tray 129 to obtain a full-color copy.

The photoreceptor 109 after the belt transfer is removed from the cleaning unit 110 (the pre-cleaning static eliminator 11).
0-1, brush roller 110-2, rubber blade 110-3)
Then, the surface is cleaned, and the charge is uniformly removed by the charge removing lamp 111.

The intermediate transfer belt 119 after the transfer of the toner image onto the transfer paper 124 is
22 is pressed again by the contact / separation mechanism 122-3 to clean the surface.

At the time of repeat copying, the color scanner 1
The operation 01 and the image formation on the photoconductor 109 proceed to the second sheet Bk (first color) image process at a predetermined timing following the first sheet Y (fourth color) image step. Further, in the intermediate transfer belt 119, the second Bk toner image is transferred to the area whose surface is cleaned by the cleaning unit 122, following the batch transfer process of the first four-color superimposed image onto the transfer paper. Be transferred. Thereafter, the operation is the same as that of the first sheet.

The transfer paper cassettes 130, 131, 1
32, 133, transfer papers of various sizes are stored, and the registration rollers 1 are set in a timely manner from a storage cassette of the size paper designated by an operation panel (not shown).
Paper is fed and transported in 26 directions. Reference numeral 134 denotes a manual paper feed tray for OHP paper and thick paper.

The above is the description of the copy mode for obtaining four full colors. In the case of the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. become. In the case of the single-color copy mode, the developing operation (spring) of the color is set until the predetermined number of sheets is completed, and the intermediate transfer belt 119 is set.
Is driven at a constant speed in the forward movement direction while being in contact with the surface of the photoconductor 109, and the belt cleaner 122 is also driven by the belt 119.
The copying operation is performed while keeping the contact with.

FIG. 3 is a block diagram of the first embodiment. 3, reference numeral 60 denotes a reading scanner, 61 denotes an image processing unit, 62 denotes an LD driving unit, 63 denotes a frame memory (1), 64 denotes a frame memory (2), and 65 denotes a frame memory (3).

At the time of normal copying, image data from the reading scanner 60 is sent to the LD driving section 62 through the image processing section 61 to modulate and write the LD. At the time of confirming the positional deviation, the image processing section 61 cuts the image data from the reading scanner 60 and stores the frame memories (1), (2), (3) 63, 64, 6 made of ROM in which the test patterns are written.
From 5, the image data is sequentially read and sent to the LD drive unit 62 for writing.

Next, the operation of the first embodiment will be described.

FIG. 4 is a block diagram showing a pattern generator according to the present invention.

In FIG. 4, 90 is a counter, 91 is a text ROM, and 92 is a font ROM.

The font ROM 92 stores font data of 8 dots × 8 dots shown in FIG.

The text ROM 91 stores data for selecting a pattern from the font ROM 92 for each image position and creating a test pattern. Text ROM 91
7 and 9 show the contents of the ROMs (1) 91 and (2) 91, respectively, and FIG.
As shown in FIG. 7 and 9 are text RO
15 shows a pattern of M91. In this method, the first image formation (black)
Is completed, a second image forming step (red) is performed, and these are superimposed to output an image in which black and red overlap as shown in FIG. FIG. 5 shows an LD driver circuit of this system.
When forming black and red images, the same driver (LD drive controller 93) is used. FIG. 11 shows a time chart of this method.

Next, a second embodiment will be described. FIG. 12 is an explanatory view showing the outline of the overall configuration of the copying apparatus according to the second embodiment, FIG. 13 is an explanatory view showing a line type exposure means of the copying apparatus according to the second embodiment, and FIG. 14 is a second embodiment. FIG. 15 is a block diagram of a pattern generator, FIG. 16 is a block diagram showing a drive circuit of a writing element (LD and LED array), and FIG.
7 is an explanatory diagram showing the contents of the text ROM 73, FIG. 18 is an explanatory diagram showing an output image of black and red data, and FIG.
A time chart showing the write timing of the D array 79,
FIG. 20 is a block diagram of a copying machine according to a second embodiment, FIG. 21 is an explanatory diagram showing an example of a test pattern according to the first embodiment of the present invention, and FIG. 22 is an explanatory diagram showing a pattern further enlarged from FIG. FIG. 23 is an explanatory view showing the state of positional deviation and parallelism deviation when a pattern is used.

This second embodiment is an explanation of a two-color color copying machine for synthesizing an image on a photosensitive member. The first image is formed by using a scanning writing system using an LD, and the second image is formed. Are those using an LED array. In any case, it is necessary to match the positions of the images of the respective colors, and it is necessary to generate a test pattern for confirming the positional deviation.

In FIGS. 12 and 13, reference numeral 1 denotes a main body of the digital copying machine, and an upper portion of the main body 1 is provided with an original reading device 3 for reading an image of the original supplied by the automatic original supply device 2. . The original reading device 3 illuminates the original supplied on the contact glass 4 by the automatic original feeder 2 with a light source 5 and sequentially reflects reflected images of the original by a plurality of mirrors 6, 7, 8. Then, a CCD image sensor (solid-state imaging device) 1 is formed by an imaging lens 9.
An image is formed at 0. This CCD image sensor 1
“0” converts the original image color-separated by a filter (not shown) into an electric signal corresponding to each color.

The photosensitive member 1 is provided below the original reading device 3.
1 is provided rotatably. Around the photoconductor 11, a first charger 12 as a charging unit, a deflection scanning type exposure unit 13, a first developing unit 14, a second charger 15 as a charging unit, and a line A mold exposure unit 16, a second developing unit 17, a transfer unit 18, and a cleaning unit 19 are provided. The main body 1 of the digital copying machine has a paper feed roller 21 for feeding out a paper 20 on a paper feed tray (not shown) mounted on one side of a lower portion of the main body 1.
A plurality of transport rollers 22, a registration roller 23,
A transfer belt 24 and a fixing unit 25 are provided.

The deflection scanning type exposure means 13 converges beam light emitted from a beam light emitting element (not shown) such as a laser diode in the sub-scanning direction by a cylindrical lens 28, and condenses the condensed beam light. Is deflected by a polygon mirror 27 driven by a motor 26, and the deflected beam light is reflected by the photoreceptor 11 via mirrors 29, 30, and 31.
Is irradiated.

As shown in FIG. 13, the line type exposure means 16 includes an IC drive circuit 33 and an LE
It is formed by housing a substrate 35 holding the D array chip 34 and a rod lens array 36 facing the LED array chip 34. The LED array chip 34 is formed by arranging a number of LEDs along the axial direction of the photoconductor 11, and these LEDs are
It is connected to the C drive circuit 33 by wire bonding.

In such a configuration, the original reading device 3
The image data read by the CCD, that is, the image data converted into electric signals by the CCD image sensor 10 in accordance with the respective colors, is sent to an image processing unit (not shown).
Then, image data of a specific color (for example, black) is output to the deflection scanning type exposure means 13, and image data of another color (for example, red) is temporarily stored in a memory (not shown). Thereafter, the image data is output to the line type exposure means 16 at a timing later than the image data of the specific color. On the other hand, the photoconductor 11 is driven clockwise, and is charged by the first charger 12 and the second charger 15 that discharge at a predetermined timing. An electrostatic latent image is formed on the charged portion by the deflection scanning type exposure unit 13 and the line type exposure unit 16. These electrostatic latent images are developed by the first developing means 14 or the second developing means 17, respectively. Then, the paper feed roller 21
When the paper 20 supplied by the feed roller 22 is conveyed to the outer periphery of the lower portion of the photoconductor 11 by the registration roller 23 that rotates in synchronization with the operation of the photoconductor 11, the photoconductor 11
The upper developed image is transferred onto the sheet 20 by the transfer unit 18. Since the paper 20 receives heat and pressure by the fixing unit 25, the transferred image is fixed.

In such a two-color digital copying machine, a black-and-white image is considered to be the main, and a high-resolution image is formed by the deflection scanning type exposure means 13 having a high pixel density. For images of other colors, such as red, which are considered to be printed less frequently, by forming an image with the line type exposure unit 16 having a short optical path length and a simple structure based on the idea of lowering the image quality level, Facilitates the arrangement of components around the photoconductor 11,
The toner containers of the first and second developing units 14 and 17 can be made large, and the size of the main body 1 can be reduced.

Further, by making the number of gradations per dot of the image formed by the line type exposure means 16 smaller than the number of gradations per dot of the image formed by the deflection scanning type exposure means 13, The content of the memory for storing the image data can be reduced, and the capacity of the memory for storing the image data can be reduced by using the line type exposure means 16 whose pixel density is coarser than the pixel density of the deflection scanning type exposure means 13. Can be reduced and therefore
Cost can be reduced.

In the above embodiment, the line type exposure means 16 having the LED array chip 34 as a main component is used. However, the line type exposure means having a fluorescent tube dot array as a main component may be used. The same purpose can be achieved by using a line-type exposure unit combining a light source and a liquid crystal shutter array or a PLZT shutter array.

As shown in FIG. 14, L-shaped support pieces 38 are fixed to a pair of left and right side plates 37 which rotatably support both ends of the photoreceptor 11, and are erected on these support pieces 38. The pins 39 hold both sides of the housing 32 of the line type exposure means 16 slidably. Housing 3
2 has rollers 40 on both sides, and the distance from the photoconductor 11 is determined by bringing the rollers 40 into contact with the outer periphery of both ends of the photoconductor 11 by the pressure of a spring 41.
An image position changing means 42 for changing the image position of the line type exposure means 16 in the main scanning direction is provided.
The image position changing means 42 includes a spring 43 for pressing the housing 32 to one side, and a housing 32 which is screwed to one side plate 37 and resists the urging force of the spring 43.
And an adjusting screw 44 for pressing the pressure. In such a configuration, by turning the adjustment screw 44, the entire line type exposure unit 16 is moved in the axial direction of the photoconductor 11, and the line type exposure unit 16 is moved in the main scanning direction of an image to be formed on the photoconductor 11 in the main scanning direction. The position can be changed.

The image transferred to the sheet S is in a state in which the image A formed by the deflection scanning type exposure means 13 and the image B formed by the line type exposure means 16 coincide with each other (a). Or deflection scanning type exposure means 13
Exposure means 16 for image A formed by
Is formed in the state (b) shifted in the main scanning direction. When this state (b) occurs,
By turning the adjusting screw 44, the line type exposure unit 16 is
By displacing along the first axial direction, the displacement of the images A and B in the main scanning direction can be prevented, and a printing state without color displacement can be obtained.

Further, as shown in FIG.
An inclination angle adjusting mechanism 45 for displacing the line type exposure means 16 in a direction inclined with respect to the axis of is provided. The tilt angle adjusting mechanism 45 has an L-shaped bracket 46 slidably provided on one side of the housing 32, a head rotatably held by the housing 32, and an intermediate portion screwed to the bracket 46. An adjusting screw 47 and a fixing screw 48 for pressing the bracket 46 against one side of the housing 32 are provided. One of the rollers 40 is supported by the bracket 46.

FIG. 20 is a block diagram of a copying machine according to the second embodiment.

In FIG. 20, reference numeral 60 denotes a reading scanner,
61 is an image processing unit, 62 is an LD driving unit, 66 is a font generator (1), 67 is a text memory, 68 is a font generator (2), 69 is a text memory, 70 is a line memory, and 71 is an LEDA driving unit. .

At the time of normal copying, image data from the reading scanner 60 is sent to the LD driving unit 62 through the image processing unit 61, and the LEDA driving unit 71 is connected via the line memory 70 for the second writing (LEDA writing). Send to This line memory 70 is for delaying writing. At the time of confirming the positional deviation, the image processing section 61 cuts the image data from the reading scanner 60, and the font generator 6 comprising a ROM in which a font pattern is written.
6, a test pattern is read from the text memory 67 for selecting the font, and the LD driving unit 62 and the LED
Send to A drive unit 71.

FIG. 21 is an explanatory diagram showing an example of a test pattern according to this embodiment. This embodiment is an example of a two-color image of black + red. A black test pattern, a red test pattern, and a composite image thereof are shown. When there is no displacement, each pattern is on the same straight line, does not overlap, and the patterns of different colors are close to each other.

FIG. 22 is an explanatory diagram showing a further enlarged pattern of FIG. 21. There are combinations of line segments, combinations of line segments and dots, combinations of dots, and the like.

FIG. 23A is an explanatory diagram showing a positional shift when the pattern of this embodiment is used, and FIG. 23B is an explanatory diagram showing a state of a parallelism shift.

In the pattern of the present embodiment, when the positions are matched, there is no overlap of the images, there is no bleeding of the pattern, and the displacement can be confirmed by visual observation, which facilitates the displacement displacement adjusting operation.

Adjustment of the positional deviation is performed by adjusting the other main-scanning write timing and sub-scanning direction write timing so as to match one of the writing positions, and adjusting the parallelism deviation by adjusting the one-side writing to the other side. Correction of the attachment position of writing of the number, etc. can be considered.

Next, the operation of the second embodiment will be described. FIG. 15 shows a block diagram of the pattern generator. In FIG. 15, reference numeral 72 denotes a counter, 73 denotes a text ROM, 74 denotes a font ROM, and 75 denotes a selector. The font ROM 74 stores the font data of 8 dots × 8 dots shown in FIG. 6 (the same as the method of the first embodiment). Text ROM
Reference numeral 73 stores data for creating a test pattern by selecting a pattern from the font ROM 74 for each image position. The text ROM 73 also stores selection data for writing in black or red in addition to font selection data. The contents of the text ROM 73 are shown in FIG.

FIG. 16 shows a write element (LD and LED array).
FIG. 3 is a block diagram showing the drive circuit of FIG. In FIG. 16, reference numeral 76 denotes an LD controller; 77, a line memory;
8 is an LED array controller, 79 is an LED array,
80 is an LD. The black image is LD80 and the red image is LE
Written in D array 79. The black and red data output from the circuit shown in FIG. 15 is corrected by a line memory 77, 77,.
Is delayed. FIG. 18 shows an output image, and FIG. 19 shows this time chart.

The present invention is also applicable to a copying apparatus of the type shown in the third embodiment. FIG. 24 is an explanatory view showing the vicinity of the photoreceptor of the copying apparatus according to the third embodiment of the present invention, and FIG. 25 is a perspective view showing an outline of the vicinity of the photoreceptor of FIG.

In these figures, reference numeral 220 denotes the photosensitive member, 2
21 is a static eliminator, 222 is a first charger, 223 is a second charger, 224 is a first deflection scanning type exposure unit, 225 is a second deflection scanning type exposure unit, and 226 is a first developing unit. ,
227 is a second developing means, 228 is a transfer unit, 229 is a cleaning unit, 230 is a fixing unit, 231 is a laser, 232 is a lens, 233 is a polygon mirror, 234
Denotes a motor, 235 denotes a lens, and 236 and 237 denote mirrors.

FIG. 26 is an explanatory view showing a modification of the third embodiment.

In the figure, 241, 242, 243, 2
44, 245 and 246 are mirrors.

[0098]

As described above, according to the present invention,
The different colors of the pattern so that it does not become heavy on the same straight line,
In addition, by using a test pattern formed so that the end points of each color are close to each other, the test pattern formed at the time of adjusting a plurality of writing positions is easy to recognize without bleeding, and it is easy to visually confirm the positional deviation. Therefore, it is possible to reduce the time and cost for adjusting the positional deviation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a color image forming apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing the periphery of a photoconductor and an intermediate transfer belt in an enlarged manner.

FIG. 3 is a block diagram of a first embodiment according to the present invention.

FIG. 4 is a block diagram of a pattern generator according to the first embodiment of the present invention.

FIG. 5 is a block diagram of an LD driver circuit.

FIG. 6 is an explanatory diagram showing font data stored in a font ROM.

FIG. 7 is an explanatory diagram showing the contents of a text ROM (1).

FIG. 8 is an explanatory diagram showing an output result of a text ROM (1).

FIG. 9 is an explanatory diagram showing the contents of a text ROM (2).

FIG. 10 is an explanatory diagram showing an output result of a text ROM (2).

FIG. 11 is a time chart of the present method.

FIG. 12 is an explanatory diagram showing an outline of an overall configuration of a copying apparatus according to a second embodiment of the present invention.

FIG. 13 is an explanatory view showing a line type exposure unit of a copying apparatus according to a second embodiment of the present invention.

FIG. 14 is an explanatory view of a copying apparatus according to a second embodiment of the present invention, showing the vicinity of a photoconductor in a cross-sectional view;

FIG. 15 is a block diagram of a pattern generator.

FIG. 16 is a block diagram showing a drive circuit of a write element (LD and LED array).

FIG. 17 is an explanatory diagram showing the contents of a text ROM.

FIG. 18 is an explanatory diagram showing an output image of black and red data.

FIG. 19 is a time chart showing the write timing of the LED array.

FIG. 20 is a block diagram of a copying machine according to a second embodiment of the present invention.

FIG. 21 is an explanatory diagram showing an example of a test pattern according to the second embodiment of the present invention.

FIG. 22 is an explanatory diagram showing a further enlarged pattern of FIG. 21;

FIG. 23 is an explanatory diagram showing a state of displacement and parallelism displacement when a pattern is used.

FIG. 24 is an explanatory view of a copying machine according to a third embodiment of the present invention, which shows a vicinity of a photoconductor in a longitudinal section.

FIG. 25 is a perspective view showing an outline around the photoconductor of FIG. 24;

FIG. 26 is an explanatory view showing a modification of the third embodiment.

FIG. 27 is an explanatory diagram showing a test pattern of a conventional color image forming apparatus.

FIG. 28 is an explanatory diagram showing a test pattern of a conventional color image forming apparatus.

[Explanation of symbols]

 Reference Signs List 60 scanner 61 image processing unit 62 LD driving unit 66 font generator (1) 67 text memory 68 font generator (2) 69 text memory 70 line memory 71 LEDA driving unit 72 counter 73 text ROM 74 font ROM 75 selector unit 76 LD controller 77 Line memory 78 LED array controller 79 LED array 80 LD

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/525 G03G 15/01 H04N 1/00 106 H04N 1/46

Claims (1)

(57) [Claims] 1. A color image forming apparatus for forming a color image by combining images of different colors obtained by a plurality of image forming steps, a memory storing a different pattern for each color, and different as non-overlapping color patterns on the same straight line, and such that each color endpoints of adjacent
Color image forming apparatus characterized by comprising a control means for controlling to form the.