JP3345448B2 - 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, and more particularly, to an electrostatic type using a laser beam, such as a laser beam printer (LBP) used as an output device of a computer system or a digital color copier. A color image forming apparatus.

[0002]

2. Description of the Related Art In the field of printers, with the progress of computer graphics and the like, the demand for printing high-definition color images by advanced image processing has increased. In the field of color copiers, high-precision gradation reproduction,
It is required to realize a clear copy in accordance with the characteristics of various copy targets such as a halftone image.

In the field where these high-quality images are required, an electrostatic latent image is generally formed by scanning a photosensitive member with a laser beam, and Y (yellow), M (magenta), C (cyan), An image is formed by developing using a color toner such as BK (black) to form a superimposed image of the color toner, and transferring the superimposed image to transfer paper at a time. Then, in order to satisfy the above-mentioned various requirements, a device such as adopting a unique method for image processing has been devised.

[0004]

(1) With the spread of OA equipment, there is an increasing demand to use a high-quality printer or the like even in a small office or the like.
The improvement of the performance of the device such as high definition is inconsistent with the convenience of the user such as low price and small size, and it is quite difficult to satisfy all of them.

For example, it is easy to perform a uniform image writing process with standard settings, which is suitable for lowering the price.
Since the control according to the individuality and characteristics of various images (or copy objects) is not performed, the color tone of the entire image becomes unsatisfactory, the color tone changes at the end of the image, or a sharp image or an oblique line is generated. The sharpness of the outline cannot be reproduced, the moiré increases in the reproduction of halftone dots, and the image quality decreases due to lack of resolution in the reproduction of small characters of 5.5 points or less. Not suitable.

On the other hand, if the image quality is to be improved only by image processing, a mechanism capable of responding to changes in various processing conditions at high speed is required, and an increase in sophisticated signal processing circuits, optical control mechanisms, and the like is required. This causes problems such as cost increase.

(2) In order to overcome the problems described above and realize a low-cost, high-quality multicolor printer, the present inventor has set the dot size and dot position within one pixel to the standard position. We studied the technology to change dynamically. According to the study by the present inventor, in the case of a single color, the dynamic dot size and dot position changing processing (hereinafter, referred to as smoothing processing) has important effects such as improvement of resolution and smoothing of an image. I understand.

However, when a color image is formed by superposing toner amounts of two colors, such as Y, M, C, etc., a change in dot size and position may hinder the alignment of the first color and the second color. It has been found that when such a change process is performed on the superimposed image, the image quality is deteriorated as compared with the case of a single color.

(3) In addition to the above-mentioned studies, the present inventor has made various studies in order to realize a low-cost, high-quality multi-color printer. It has been found that formation of a color image that requires superimposition involves problems such as consistency of colors to be superimposed, and it is difficult to improve the image quality.

Therefore, a first object of the present invention is to improve the quality of a color image, which is particularly necessary in an image forming apparatus, by a simplified configuration, and to reduce the cost (small size).
Another object of the present invention is to provide an image forming technique that achieves high image quality.

A second object of the present invention is to effectively use a technique for dynamically changing a dot size and a dot position within one pixel when an image is formed by overlapping toners (developers) of different colors. To improve the image quality of a multi-color image.

A third object of the present invention is to achieve the maximum improvement in image quality for both monochrome and color images.

[0013]

A typical structure of a color image forming apparatus according to the present invention is as follows.

(1) When a dot of one pixel is written on a photoreceptor with a laser beam, the center of the laser beam can be deviated from a standard position in the pixel. The laser beam diameter can also be changed (because it has an important effect of smoothing an image, such a process of dynamically changing the dot writing position and the dot size is hereinafter referred to as a smoothing process.
3). A semiconductor laser diode is used as a writing light source.
(Pulse width modulation) Drives with a pulse width signal. (In normal writing, the position where the pulse width signal is generated is specified in one pixel, and the pulse width is controlled based on the position. To control the irradiation energy). The above-described smoothing process is performed by controlling the generation timing of the pulse width signal and the pulse width thereof using a correction signal different from the standard (FIGS. 13A to 13C). In this case, the writing position can be changed only in the main scanning direction of the beam, but if it is necessary to change the writing position in the sub-scanning direction, the angle of the reflection surface of the polygon mirror must be changed. This is performed by changing the optical path using a lens or a lens (FIG. 13D).

(2) An image for which the smoothing process is particularly effective is determined in advance, and at least the portion is subjected to the smoothing process. Examples of where the smoothing process is effective include edge portions (including isolated dots in addition to image edges), sharp figures, oblique lines,
There are halftone images, grayscale images, and small characters (characters with 5.5 points or less). Among them, particularly, the edge portion in the case of mono color is easy to recognize, and the effect of smoothing the screen is great.

(3) In addition to the smoothing process, a hue correction process is performed, and two types of processes having different concepts are selectively used. The hue correction process is a correction for realizing a desired hue by controlling the ratio of the toner amount of each color to a predetermined ratio when the colors need to be superimposed. Usually, the latent image of the first color is superimposed. Performed during formation. This hue correction is essentially different from the smoothing process of changing the recording position and dot size by focusing on the shape of the image and the like. , Pulse width signal generation processing). In this case, when the two corrections conflict, the smoothing process is prioritized, and the hue correction is performed for a dot for which no smoothing process instruction is given. Such proper use is performed, for example, as follows. That is, the input image signal is matched with a template pattern (which is basically composed of a plurality of high-speed comparators), and if the conditions of this pattern are met, a smoothing process is performed on the dot to correct the color tone. Is ignored. If the smoothing process is not performed without matching the predetermined pattern, it is next determined whether or not the dot is a dot formed by superimposing toner images of different colors. , For the first color.

This situation is shown in FIG. FIGS. 11A to 11C are views for explaining the features of dot formation according to the present invention, taking as an example a case where a diagonal line of red (R = Y + M) is printed. (A) shows a dot forming method in the case where only the hue correction is performed without performing the smoothing process, and (b) shows the case in which both the smoothing process and the hue correction are performed (in addition, the smoothing process dots are also used). The following describes a dot forming method of performing color correction). (C) shows a case where the smoothing process and the hue correction are performed alternatively. In the drawing, the hatched dots are the smoothing-processed dots.
Y = M for this dot, and no consideration is given to color correction. On the other hand, for the dots that are not subjected to the smoothing process, it is determined whether or not they are isolated dots or edge dots. For the dots that are determined as such, the first color is compared with the dots that are not determined as such. Intensify the image exposure to increase the Y toner adhesion amount.

(4) When forming a color image, it is necessary to superimpose toners of different colors (for example, the first
Color toner and the second color toner).
When the first color toner is subjected to the smoothing process, the second color toner is also subjected to the smoothing process.

In such processing, for example, first, a dot to be subjected to smoothing processing is selected by matching with a template, and then, for the dot, the presence / absence of color superposition is checked from the information in the frame memory. Further calculations are performed on the dots to determine the final dot diameter and dot placement.

FIG. 11B shows a red (R) image using this method.
= Y + M) is shown. In the case of (b), the hue correction for slightly increasing the Y of the first color is also performed for the smoothed dots. In this case, the degree of hue correction is appropriately adjusted according to the dot size.

(5) The hue correction is performed as shown in FIG.
It includes color correction for the entire image (left side in FIG. 2) and color correction at the edge portion (right side in FIG. 2).
In the color correction for the entire image, as shown on the left side of FIG. 2, the first color toner reduces the exposure power of the second color reaching the photoconductor, and the second color toner amount is reduced. In this correction, the amount of the first color toner is reduced, the reduction in the exposure power of the second color is reduced, and the ratio of each color is optimized. As shown in the right side of FIG. 2, when the edge position is shifted due to the difference between the pulse widths of the first color and the second color, as shown on the right side of FIG.
Since a state where the first color and the second color do not overlap occurs and the color of the edge changes, the correction is performed by adjusting the pulse width to align the edge positions of the respective colors.

(6) Adding a color tone correction process to the smoothing process, and further changing the content of the color tone correction process according to the level of the dot size of the smoothing process so as to ensure consistency between the first color and the second color. And at each level of the smoothing process, an equivalent desired color tone is realized.

(7) More specifically, in the process of performing the smoothing process, the dots which are the isolated and the edge are determined at the same time. As the dot diameter is reduced by the smoothing process, the ratio of the toner adhesion amounts of the first color and the second color is adjusted so that the ratio of the toner adhesion amount of the first color to the toner adhesion amount of the second color increases. hand,
The edge color correction processing is executed.

(8) In the case of a single color (mono color) mode,
A technique (smoothing processing) for dynamically changing the dot size and the dot position within one pixel is preferentially performed to improve the resolution and smooth the image. On the other hand, in the case of the color mode, for the color dots formed by superimposing the first color and the second color, and for the dots constituting the isolated dots or the edges, the edge color correction for exposing the first color more strongly than the standard. And give priority to
Achieve the desired shade.

(9) When one print is executed by selecting the color mode, a single-color image area and a color image area formed by superimposing colors are discriminated in the one image image, and For the color image area,
Discriminate between isolated or edge dots and solid dots,
For monochrome image areas, smoothing processing is performed with priority,
For the color image area, the edge tone correction is performed with priority.

[0026]

[Function] Means for solving the problem (1)-
The operation of (5) will be described below with reference to FIG.

(1) According to the study of the present inventor, it has been found that the smoothing process (the process of changing the dot position and the dot size within one pixel) has the following effects. This has the effect of increasing the apparent resolution. For example, 5.5
Even characters with small points can be reproduced in detail. Also, the edges of the character become clearly visible as after edge emphasis. When used for a halftone image, each dot of the original halftone dot is reproduced. As a result, moire is relatively inconspicuous. Even when used for an image having a gradual change in density such as a photograph, there is not much change (that is, there is no adverse effect). Since the amount and position of toner adhesion can be controlled, the color tone and image roughness can be controlled, and the image quality can be improved. That is, a plurality of effects leading to an improvement in image quality can be obtained by a simple electrical operation of controlling the timing and period of the pulse width modulation signal.

(2) The execution / non-execution of the smoothing process is performed by, for example, matching with a template pattern. In this case, it is easy to make a determination by narrowing down the target to be processed to a certain extent without making the target wider. That is, there are an edge portion (including an isolated dot in addition to the edge of the image), a sharp figure, an oblique line, a halftone image, a gray image, and minute characters (characters of 5.5 points or less). In particular, since the edge portion in the case of mono color is easy to recognize and the effect of smoothing the screen is great, the priority of the smoothing process is increased.

(3) In addition to the smoothing processing, color correction is performed, and by properly using them, the color reproduction function can be enhanced in addition to the apparent resolution increase and the effect of sharp shape reproduction. . In this case, as described above, first, the necessity of the smoothing process by matching with the template pattern is determined, and if necessary, the smoothing process is prioritized. For the dots having overlapping colors, the procedure for correcting the hue is performed by performing an operation for the hue correction. This method has an advantage that hardware and an algorithm (software) required for processing are simple. In addition, since both means for realizing both corrections are the same electrical operation of controlling the timing and period of the pulse width modulation signal, the optical unit and the like are not complicated. In addition, since the image pattern and color information necessary for judging the proper use of these corrections are commonly used for both the smoothing process and the color tone correction, a special information collecting step for independent correction is unnecessary. It is.

(4) When the first color dot of the color image is subjected to the smoothing process, the second color and subsequent dots superimposed thereon are also smoothed. As a result, matching of dot overlap is maintained, and a desired color can be reproduced while obtaining the effect of the smoothing process described in (1). Also,
By performing the hue correction, a desired hue can be realized. According to this method, both the complete hue correction and the smoothing of the image can be realized.

(5) The color reproduction function can be enhanced by including both the correction of the entire image (the center of the image) and the correction of the edge portion as the hue correction. FIG. 3 summarizes the above operations (effects).
That is, the correction mode of the image forming apparatus of the present invention includes a mode of only color correction (mode A), a mode in which smoothing processing is performed only on monocolor dots, and a color correction is performed on other dots (mode B). A mode in which smoothing processing is performed on all dots (including multi-color) that require smoothing processing, and a hue correction is performed on dots that are not subjected to smoothing processing (mode C), and all dots that require smoothing processing (mode C) There is a mode (mode D) in which a smoothing process is performed on the multi-color (including multi-color), and the hue correction is performed on all of the dots having the overlapping colors including the smoothed dots.

FIG. 11 (a) shows the results of the processing of mode A and mode B for the dots having the superimposed colors, and FIG. 11 (b) shows the results of the processing of mode C and mode D, respectively. b) and (c).

In the case of mode C, as shown on the right side of FIG. 3, smoothing and edge (contour) by smoothing processing are performed.
The effect of emphasis and the appropriate color reproduction effect by hue correction
Obtained together. In the case of the mode D, a perfect color tone can be realized for the smoothing dot. In the color correction, the edge A and the edge B are selectively used in FIG. 3, and the edge A is an edge for which the color correction is performed, and the edge B is a background of the first developed color (background by a solid image). ) Is the boundary of the superimposed image of the second color when creating the superimposition of the second color (in order to correct the phenomenon that the toner does not easily adhere to the boundary of the image of the second color, It is used to strongly expose the second color).

Next, the operation of (6) and (7) in the section for solving the problem will be described with reference to FIG.

(6) In the smoothing process, as shown in the column (4) (rightmost column) in FIG.
This is performed when realizing a sharp outline of the image, and basically, each dot subjected to the smoothing process is an isolated dot or a dot that forms an edge (contour of a figure). Unlike isolated dots and solid dots (dots that collectively constitute a solid figure and another dot is present next to the dots), the light beam is continuous during the formation of an electrostatic latent image. Therefore, when the pulse width of the driving pulse of the light source (semiconductor laser) is reduced without the interaction of the light beams, the average light intensity of the light beam rapidly decreases. That is, since the isolated dots and the edge dots are formed by a single light beam, there is a characteristic that the change rate of the light intensity with respect to the pulse width is large.

Accordingly, for a dot (multi-color dot) formed by superimposing colors, a pulse signal for driving a semiconductor laser is dynamically changed by smoothing processing to change the dot size of the first color and the second color. When the pulse width is successively changed, the light intensity of the light beam changes non-linearly in relation to the size level of the dot to be formed, and the effect is that the first color and the second color do not match. And appear remarkably.

That is, as shown in the upper right of column (4) in FIG. 12, when the duty of the signal of the pulse width is changed from 0 to Full, the dot size of the isolated dot (the size of the light beam) becomes As shown by the solid line, the area where the duty is small shows a steep change, and the area where the duty is large shows a gentle characteristic and has non-linear characteristics. Therefore, the duty ratio of the first color and the second color is uniform. Once fixed (for example,
1: 2), when the dot size is reduced, the first
As for the color, the amount of toner attached to the first color is actually reduced due to the extreme decrease in the light amount due to the duty reduction, and the color tone is changed as compared with the case where the dot size is large. That is, if the duty ratio of the first and second colors is fixed uniformly,
When the dynamic control of the size of the multi-color dot is performed, the color tone is slightly different depending on the size level, and it is difficult to form a sharp color image with a blurred hue and accurate color tone.

Therefore, when performing smoothing processing on isolated and edge dots, the duty of the first color and the duty of the second color
The duty ratio is changed according to the dot size without fixing, and the same color tone is realized for all sizes by making the effects of the first color and the second color equal.

(7) More specifically, as the dot size becomes smaller, the tendency for the light quantity of the first color to decrease becomes stronger. To correct this, the first color is exposed more strongly. That is, as the dot size decreases, the ratio of the exposure duty of the first color to the second color increases. For example, as shown in the table shown at the bottom of the column (4) in FIG. 12, the dot sizes of the edge (isolated) dots are set to (a), (b), (c), (d), Full
When divided into five stages, the duty ratio of the first color and the second color is
"1", "0.75", "0.67", "0.62", "0.5". Exposure of the first and second colors due to such a duty is similarly shown in the upper left column of column (4), and when these are superimposed, an image of a tapered line without color disturbance is formed. (Upper center of column (4)).

As described above, countermeasures and the like associated with a change in dot size have been described for edge (isolated) dots. For solid dots (dots that collectively form a solid image), the footprint of the light beam for forming each dot is determined. The parts overlap each other, and the power to form a uniform light intensity distribution is strong,
Since the influence of the duty change of each dot (particularly, the reduction of the duty) does not immediately lead to a sharp decrease in the light amount, the necessity of the first color stronger exposure as in the case of an isolated dot is reduced.

Therefore, when compared with full-size dots, solid dots can narrow down the duty of the first color closer to the theoretical value as shown in columns (2) and (3) of FIG. it can. That is, in the case of solid dots, the duty ratio of the first and second colors is 30: 100, and the duty of the first color is smaller than that in the case of isolated dots (50: 100).

As shown in the column (1), even if the theoretical value has the same duty as the first color and the second color, the solid dot, the
In both the edge dots, the duty of the first color is smaller than that of the second color. This is because the toner image of the first color interferes with the exposure beam of the second color and the actual hue does not match the theory. (This is referred to as hue correction).

An image forming apparatus (such as a printer) that performs dynamic color correction when performing such smoothing processing on edge (isolated) dots requires a toner adhesion amount of the first color and a toner adhesion amount of the second color. A toner adhering amount adjusting means for adjusting the adhering amount, a smoothing processing means for dynamically controlling a diameter of the toner dot in one pixel to improve an apparent resolution, and a dot to be formed is an isolated dot Alternatively, the image processing apparatus includes an edge determination unit that determines whether or not the dot is a dot constituting an edge.

The edge judging means may be, for example, a dot condition signal (for example, image information is developed into a bitmap, the bitmap data is matched with a template, and each dot is a dot to be smoothed, Means for detecting in real time in the print execution stage that the dot is an edge or an isolated dot, based on a plurality of bits indicating the result when it is determined that the dot constitutes an edge beyond the edge It is.

The toner adhering amount adjusting means and the smoothing processing means execute processing having different concepts. For example, the realization is achieved by driving a writing light source (such as a semiconductor laser) for forming an electrostatic latent image. This can be realized in common by controlling the generation of the PWM signal. That is, the control of the toner non-adhesion amount can be realized by controlling the pulse width to increase or decrease the light intensity.

The smoothing process (dynamic change of dot placement and dot size within one pixel) can be realized by controlling the generation timing and pulse width of the pulse width signal. That is, in the normal writing, the position where the pulse width signal is generated is specified in one pixel, and the pulse width is controlled based on the position to control the trading company energy. The signal generation timing and its pulse width are controlled by a correction signal different from the standard. The control by the PWM signal
Since it is high-speed, accurate, and has a simplified configuration, it contributes to the cost reduction of the image forming apparatus.

Next, the operation of the means (8) and (9) for solving the problems will be described.

(8) According to the study of the present inventor, in the case of a single color, the dynamic dot size and dot position changing process (smoothing process) reproduces a sharp outline such as an oblique line or a tapered line. As a result, it has been found that it has important effects such as improvement in apparent resolution and smoothing of images.
However, when a color image is formed by superimposing two color toner layers such as Y, M, C, etc., a change in dot size and position is a factor that hinders the alignment between the first color and the second color. Performing the processing on the superimposed images has proven difficult.

Therefore, the smoothing process is performed only in the monochromatic mode, and in the color mode, the edge tint is corrected in place of the smoothing process to prevent the color tone from being disturbed at the edge (isolated) portion. Reproduce the contours of natural color images. Thereby, the image quality of both the monochrome image and the color image is improved.

(9) A single color image / color image is discriminated from one image in the color mode, and the smoothing process is preferentially performed on the single color image.
Edge color correction is performed with priority. In this case, a smoothing process can be executed for each of the first color and the second color for a color image that particularly requires sharp outline enhancement or the like.

[0051]

Next, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing the overall configuration of an embodiment (a seven-color multi-color page printer) of an image forming apparatus according to the present invention. This embodiment includes a printer controller 3 (including an operation board 4) and a printer main body 5.

The printer controller 3 decodes image information (mainly a page description language) from the host computer 2 and develops it into bitmap data, and sends it to the video interface 100 in the printer main body 5. And sends a command to the host 2, the operation board 4, and the video interface 100. Usually, the printer controller 3 is integrated with the main body.

The components include a high-speed CPU 6, a plane memory 9 (9a to 9c) for holding data of one page that has been bit-mapped, a RAM 10, a dot condition determination circuit 11, and the like. Plain memory 9a, 9
b and 9c store dot data of each color of Y, M and C, respectively, and when the data of these three memories are all "1", it means BK (Y + M + C). The dot condition determination circuit 11 outputs, for example, 6 × 6 dots of dot data of each pixel output from the plane memories 9a to 9c.
A small area of 6 pixels is extracted, and the necessity of smoothing processing is determined from the positional relationship and the like within the small area. If it is determined that it is necessary, whether or not it corresponds to the dot printing position, dot size designation information, or an edge is determined. Is output (information used in the above-described smoothing process).

The printer body 5 includes a CPU, a mechanical control 16
A video interface (which controls charging, exposure, transfer, fixing, etc.) and image data processing (which generates timing for reading and writing image data, processes image data, selects command data, etc.) It comprises a one-chip gate array) 100, a timing generation circuit 15, an optical control unit 17, and a printing unit 18. The video interface 100 has an input conversion circuit 12, a condition determination processing circuit 13, and a print condition storage register group 14.

The timing of all the operations is performed in dot units with reference to an index signal IND (a signal indicating that the beam has reached a predetermined position near the leading end of the image on the photosensitive member) obtained from the printing unit 18. That is, the index signal IND is supplied to the timing generation circuit 15,
On the basis of this, a high-speed clock (5 MHz) in units of dots whose phases are synchronized is generated, and this high-speed clock is sent to the printer controller 3 and the like, and dot data is transferred in synchronism with this and signal processing is performed in real time. Then, printing is executed.

FIG. 4 shows the details of the embodiment of FIG. 1 in more concrete form. 1 is substantially the same as the configuration of the device in FIG. 1, but differs in that the timing circuit 15 is incorporated in the video interface 100 in consideration of measures against radiation noise and the like. In FIG. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals. FIGS. 5 to 10 are diagrams for explaining the features of the configuration of FIG.

[Structure] As shown in FIG. 4, the video interface 100 in charge of the image signal processing includes, in addition to the input conversion circuit 12, a mode conversion circuit 64 for switching the mode shown in FIG. , A test pattern generator (TP) 51, a selector 52, and a single color detection circuit (M
O) 54, an edge detection circuit (EG) 55, a video control circuit 56, a smoothing processing control circuit (SO) 57, register groups RG1 to RG28 (14), and an OR circuit 60.
And a laser control circuit 62 and a control circuit 63 (which outputs control signals CL1 to CLn to each circuit while transmitting and receiving information to and from the CPU and the mechanical control 16) for controlling the operation of these circuits.

The input conversion circuit 12 converts the video signal from the printer controller 3 into Y, M,
The signal is converted into a 4-bit signal of C and BK. The test pattern generator (TP) 51 is a ROM for outputting a fixed test pattern without a controller. The selector 52 selectively passes the test pattern and the normal video input signal. The single-color detection circuit 54 detects a single-color dot from the video signal, and notifies the mode conversion circuit 64 if it is a single-color dot.

The edge detection circuit (EG) 55 decodes the 5-bit control signal AN for smoothing processing from the printer controller 3 and notifies the mode conversion circuit 64 when data indicating an edge is sent. . Mode conversion circuit 6
4 generates an output corresponding to the modes A and B shown in FIG.

When there is a command to change the dot (beam) position and dot size, the smoothing processing control circuit (SO) 57 activates the disable terminal E of the video control circuit 56 to prioritize the smoothing processing, and Any of the registers RG1 to RG28 storing the various conditions is accessed, and the stored data is output. The video control circuit 56 operates when the smoothing process is not performed, and stores the necessary condition in accordance with the video signal.
Access any one of G1 to RG28,
The stored data is output. The data driver 61 transmits the code to the optical control unit 17.

The optical control unit 17 includes a data decoder 70
, A PWM modulation circuit 71, a laser on / off signal generator 72, a laser driver 73, a writing laser diode D1, a monitoring photodiode D2, and an index signal receiving photosensor SE. The printing unit 18 includes a photosensitive drum 80, a charger 81, and a developing device 82 for four colors. The rotation of the photosensitive drum 80 is controlled by a stepping motor 83, and the number of rotations is synchronized with the index signal.
If more precise control is required, the rotation is detected by the encoder, and the CPU and the mechanical controller 16 perform closed loop control.

[Operation Timing Control] FIG. 5 is a timing chart for explaining the operation timing of the printer shown in FIG. An operation clock of 5 MHz is generated by the timing circuit 15 with reference to the index signal (IND), and processing for every dot is performed in synchronization with this clock. When the index signal is counted 3,700, the photosensitive drum 80 makes one rotation, and the development of the first color of the image for one page is completed. Further, after the development of the first color is completed, the intensity of the laser light is adjusted in a non-image period of the period until the start of the development of the second color.

[Input of Video (Dot) Data] As shown in FIG. 6, in order to reproduce a multi-color image of seven colors,
Data of development surfaces of four colors of Y, M, C, and BK are required. In the present embodiment, as shown in FIG. 7, frame memories 9a, 9b and 9c corresponding to respective colors of Y, M and C are provided.
The dot data f1, f2, and f3 for each color are output to the input conversion circuit 12. The input conversion circuit 12 includes f1, f2, f
Then, the meaning of the input information (shown on the right side of FIG. 7) is determined from the CPU 3 and the information CSEL indicating the current development color provided from the mechanical controller 16, and information indicating the superposition of colors is output.

[Content of Information AN for Specifying Dot Printing Position and Dot Size and Information of Whether or Not Corresponds to Edge] Information AN used for the smoothing process is as shown in FIG. 4 (FIG. 1). The dot condition determination circuit 11 in the printer controller 3 outputs the data as 5-bit data. The dot position (Placement), dot size (Size), and whether or not an edge corresponds to the code are shown in FIG. It has become. Here, Full represents a dot for which the smoothing process is not performed. The video interface circuit 100 determines the code based on the promise, and determines whether or not the smoothing process is performed and whether or not the edge process is performed.

[Selection of correction conditions etc. by register designation]
In the printer of the present embodiment, high-speed processing is required because it is necessary to determine correction conditions and the like in real time and send them to the optical control unit. On the other hand, the dot size and position can be finely controlled, and there are many correction conditions, so that signal processing may be delayed. Therefore, as shown in FIG. 4 (FIG. 1), a register is provided for each correction condition,
The direct output of correction conditions and the like was stopped, and an indirect output method by specifying a register number was adopted. As a result, correction conditions and the like can all be managed by register numbers, and together with high-speed processing,
Management becomes easy. The change of the data stored in the registers RG1 to RG28 is performed by operating the keyboard of the operation board 4.
Easy to do. The condition stored in each register (0 to 28) (that is, the meaning of the stored data) is, for example,
As shown in FIG.

[Simplification of Write Beam Control Mechanism] In the apparatus of this embodiment, in addition to real-time signal processing,
Although accurate scanning of the laser beam according to the M modulation wave is required, the configuration tends to be complicated. Therefore,
As shown in FIG. 10, the relationship between the signal processing system A and the system B that scans a laser beam by receiving a signal from A is devised, and the configuration of the system B that scans a laser beam is simplified as much as possible. . That is, as shown in the upper part (form 1) of FIG. 10, all the processes up to the selection of the printing condition are performed by the video interface A1, and only the encode signal is sent to the configuration B1, so that the B1 side Other than the laser driver,
Only the PWM modulation circuit is sufficient, and the configuration is simplified. Also, the amount of transmission data between A1 and B1 can be small. On the lower side of FIG. 10 (mode 2), all the signal processing is performed in the configuration A2, and in the configuration B2, only the laser is turned on. A2 and B2 are low-loss transmission lines LN1.
And the distortion of the driving pulse is reduced.

[Function for Performing Dynamic Tone Correction Accompanying Smoothing of Printer] As described in the section of operation, the printer of this embodiment has a smoothing function as shown in section (4) of FIG. Edge tint correction is performed simultaneously with the conversion process, and the content of the edge tint correction (P color of the first and second colors)
It has a function of appropriately changing the duty ratio of the WM according to the level of the smoothing process (the level of the dot size). The smoothing process changes the dot size and the dot position within one pixel, and performs a pulse width signal (PWM).
The pulse is generated by controlling the generation timing and the pulse width of the pulse with a correction signal different from the standard.

The dot position and size within one pixel can be changed as shown in FIGS. In this case, the writing position can be changed only in the main scanning direction of the beam, but if it is necessary to change the writing position in the sub-scanning direction, the angle of the reflecting surface of the polygon mirror should be changed. This is performed by changing the optical path using a lens or a lens (FIG. 13D). By performing the smoothing process, the image quality of a sharp image or the like can be improved.

[Outline of Configuration for Performing Multicolor, Smoothing Processing, and Dynamic Edge Tint Correction] FIG.
FIG. 3 is a diagram extracting and showing an internal configuration of the condition determination circuit 13 (particularly, a portion that realizes a function shown in a column (4) of FIG. 12) from the configuration of FIG. Condition determination circuit 13
Are a single color detection circuit (MO) 54 and an edge detection circuit (E
G) 55, a mode conversion circuit 64, a video control circuit (VO) 56, and a smoothing processing control circuit (SO) 57.

The mode conversion circuit 64 switches modes as shown in FIG. 3, and is controlled by control signals CL8 and CL9 from the mechanical controller and the CPU 16. In the case of mode A in FIG. 3, the control signal CL8 is set to the high level, and in the case of mode B, the control signal CL9 is set to the high level.

The smoothing process control circuit (SO) 57 switches between the mode C in FIG. 3 and the other modes by the control signal CL10.
The correction operation is performed, and in the other modes, no operation is performed, and the register (REG1) is operated in accordance with the code shown in FIG.
To REG28). For example, if AN is Full in FIG.
In this case, an enable signal is sent to the video control circuit 56 without performing the smoothing process.

The video control circuit 56 selects a register for color tone correction (edge portion and whole) from the CSEL signal indicating the current development color, the video signal, and the edge signal from the edge detection circuit (EG) 55, and smoothes the register. The data (superimposition, developed color) for mode C correction is sent to the conversion control circuit (SO) 57.

By the above processing, the modes A to D shown in FIG. 3 are switched by a command from the mechanical controller and the CPU 16, and the optimum register for each dot is determined from the video data, AN signal and CSEL data by the register group (REG).
1 to REG28) to output stored data preset in each register.

According to the output data, the optical control unit 17
The PWM control circuit operates to drive the semiconductor laser (light source). For multicolor and edge dots, the exposure amounts of the first and second colors are controlled as shown in column (4) of FIG. 12 so that an electrostatic latent image is formed on the photosensitive drum 80. It has become.

In the above embodiment, both the means for adjusting the amount of toner adhered and the smoothing means are realized by controlling the pulse width signal for driving the light source. However, the present invention is not limited to this. Rather, regarding the means for adjusting the amount of toner adhesion, the adjustment of the light source (laser) power
It can be used alone or in combination with pulse width control. Further, when used together with the uniform adjustment of the amount of applied toner on the entire screen, for example, the adjustment of the developing bias, the adjustment of the number of rotations of the sleeve, the adjustment of the toner density, etc., the density adjustment of the entire screen can be performed at the same time. It is possible to realize better isolation of the toner image or better reproduction of the edge portion.

[Other Embodiments] Another embodiment will be described with reference to FIGS. As described above, the modes include the color mode and the multi-color mode, and can be switched by an input from the host 2 or the operation board 4.

When the multi-color mode is designated, development or transfer is repeated a plurality of times on an image carrier or a transfer material to form an image to be superimposed. In this case, dots composed of only a single color toner and dots composed of a plurality of toners may be mixed. The mono color mode does not have the above-mentioned superposition process.

FIG. 15 is a diagram showing a configuration of an embodiment for performing switching in consideration of each mode of mono-color and multi-color. FIG. 15A shows smoothing (smoothing processing) when a mono-color mode is designated. (B) shows a mode in which only color correction is performed in the multi-color mode. In (b), the color correction is performed so that the color tone of the hunted dot and the other dots in the edge and isolated dots is changed by changing the pulse widths of the first color and the second color depending on the pattern. FIG. 16 shows a processing example when a color image in which a monochrome image and a multi-color image are mixed is processed.

First, the area A is a case where the edge portion of the monocolor image is processed. When performing PWM control of the semiconductor laser at the time of image exposure, the pulse width signal is controlled at the edge portion of the black circle to control the dot size and / or dot size. This is an example in which the dot position is changed in dot units and writing is performed so as to be attached to dots other than the edge portion of the white circle. By doing so, a diagonal line or a tip portion of the edge portion of the monocolor image is reproduced as a high-resolution image in which the edge portion is smoothed.

A region B is a case where isolated dots and edge dots of a multi-color image are processed, and shows an example in which only color correction is performed. At the time of image exposure and PWM control of the semiconductor laser, the hatched dots are controlled to control the pulse width signal of the first color and / or the second color so that the color tone is reproduced in the same color tone as that of the white dot. . Specifically, the ratio between the pulse widths of the first color and the second color is determined according to the size of the dot or the color tone to be reproduced.

For a multicolor image, as shown in a region C, both color correction and smoothing may be performed. In this case, not only the ratio of the pulse width of the first color to the pulse width of the second color is controlled on a dot-by-dot basis with respect to multi-color edge dots or isolated dots, but also the dot position is controlled so that dots other than the white circle edge portions Write so that it is adjacent to. In this case, the color tone is reproduced more vividly. In addition, a smoothing effect appears, and a high-quality color image can be obtained.

Next, the color image forming process will be specifically described.

FIG. 18 is a diagram showing a configuration of a main part of a printer adopting a process of forming a superimposed toner image by rotating a photosensitive drum a plurality of times when a color image is formed.

In this embodiment, a band electrode 202, an exposing unit 203, and a developing unit 204 are mounted on a photosensitive drum 201 as an image carrier.
, A first image forming unit and a band electrode 205, an exposing unit 206, a developing unit 207, a second image forming unit, a band electrode 208, an exposing unit 209, and a developing unit 210.
Is provided as a set, and a yellow color toner is applied to the developing unit 204, a magenta color toner is applied to the developing unit 207, and a cyan color toner is applied to the developing unit 210 of the first image forming unit. Inject color toners respectively. Then, after a charge is applied to the photosensitive drum 201 by the band electrode 202, the exposure unit 203 applies D
Then, light control is performed based on the uty, and then the developing unit 204 develops the yellow color toner. In the next stage, the photosensitive drum 201 and the yellow color toner are immediately charged,
Exposure means 209 performs the charge erasure control by the pulse width control, and the developing section 207 develops the magenta color toner. Alternatively, the image is superposed and developed using cyan color toner of the third image forming means. This method is a method in which the photosensitive drum 201 can process the image by one rotation of image formation. The color image is transferred to the recording paper P by the transfer pole 211 and the color toner conveyed between the heat fixing roller 212 and the pressure roller 213 is recorded on the recording paper Fix to P.

FIG. 19 is a diagram showing the main configuration of an apparatus employing a so-called belt transfer type process. This embodiment is an image forming apparatus using the color image forming process of the present invention as described above, in which a first image in which a band electrode 310, an exposure unit 311 and a developing unit 312 are provided on a photosensitive drum 309 as an image carrier. A second image forming unit provided with a band electrode 306, an exposing unit 307, and a developing unit 308 for a photosensitive drum 305; and a band electrode 302, an exposing unit 303, and a developing unit 304 for a photosensitive drum 301. A recording paper transport belt 313 which is in common contact with the photosensitive drums 309, 305, 301 of the first, second, and third image forming means; The transfer poles 314, 315, and 3 are located at positions facing 309, 305, and 301 via the recording paper transport belt.
The developing unit 312 is provided with yellow, the developing unit 308 is provided with magenta, and the developing unit 304 is provided with cyan color toner. Utilizing the color image forming process of the present invention of the present apparatus, first, the photosensitive drum 309 to which the charge is applied by the band electrode 310 is exposed by the exposure unit 311 which performs the light control by the duty, and the developing device 312
After the development, the recording paper P is conveyed by the recording paper conveyance belt 313 and the transfer pole 3
The yellow image is transferred to 14. Next, the photosensitive drum 305 charged with the band electrode 306 is subjected to light control using Duty to superimpose the second toner on the recording paper P, and then the magenta color toner is developed by the developing device 308. The transfer electrode 315 is developed such that the magenta color toner formed on the photosensitive drum is superimposed on the yellow color toner formed on the recording paper P.
Transfer with. 18 and 19, the two color toners are configured to use the image forming process of the present invention so as to uniformly transfer the amount of the color toner by superimposing the two colors. In the above embodiment, only the three primary color toners have been illustrated, but a developing device using a black toner may be added.

Although not shown in this embodiment, a method of forming a three- or four-color color toner image on the photosensitive drum and then transferring the color image to recording paper via a transfer drum is used. You may.

By using the above values, the difference in the tone between the line in the dot image portion and the tone in the solid image portion was almost eliminated in any color tone.

This adjustment is performed by a knob on the operation panel or a signal from the host 100. Although the above example has been described as a three-method step, it may be changed continuously.

Further, a color image can be formed in a desired color by using the above-described adjustment method.

Next, the configuration of a printer using the process of the image forming apparatus will be described with reference to FIG.

In FIG. 17, reference numeral 1 denotes a lower frame of the image forming apparatus, in which a half-moon-shaped paper feed roller 2 for feeding recording paper P as a transfer member is provided. Are provided in the lower frame 1 in a detachable manner. A spring 5 is provided in the paper cassette 3.
A push-up plate 4 is provided, which is pushed up by the recording paper P. The recording paper P is placed thereon, and a separation claw 6 rotatably provided on a part of the paper feed cassette 3 is locked to the top end of the recording paper P. I do. Reference numeral 7 denotes a guide plate for guiding both sides of the recording paper P, which is provided so as to be adjustable depending on the size of the recording paper. The above configuration is provided in the paper feed cassette 3. Reference numeral 8 denotes a conveyance roller for the recording paper P provided on the lower frame 1, and is provided between a guide plate 9 for guiding the leading end of the recording paper P fed by the paper feed roller 2 and a reversing guide plate 10. .

Reference numeral 11 denotes a guide plate for guiding the recording paper P to the registration roller 12 after reversely feeding the recording paper P. The guide plate 11 guides the recording paper P to the registration roller 12. 13 ON the sensor S ₁ for detecting the recording sheet P at the position of the resist roller 12, a swing member which turned OFF. Reference numeral 14 denotes a guide plate for guiding the recording paper P, which has passed through the registration rollers 12, toward the transfer belt 15. The transfer belt 15 is suspended by a transfer roller 16, a roller 17, and a drive roller 18. Reference numeral 15a denotes cleaning means for cleaning the surface of the transfer belt 15. Reference numeral 19 denotes a fixing device for fixing an image transferred onto the recording paper P, which comprises a heating roller 20 for fixing and a pressure roller 21. A cleaning roller 20a is pressed against the heating roller 20 for fixing, and cleaning is performed according to rotation. I do. 22 is a discharge roller for discharging the recording paper P from the fixing device 19, ON the sensor S ₂ for confirming sheet discharge of the recording paper P, is operated by the recording paper swing member 23 to OFF when the paper discharge. The discharged recording paper P is fed to the upper frame 1 by a recording paper guide member 24, a guide passage 25 formed in the upper frame 1c, and guide conveyance rollers 26 and 27.
c, the recording paper P
Is configured to be discharged. Next, an image carrier 29 (hereinafter, referred to as a photosensitive drum 29) for image formation is provided at a substantially central portion of the upper frame 1c, and four developing devices 30 are provided along the surface of the photosensitive drum 29 from above. , 31, 32, and 33 are provided, respectively, in the developing device frame 30a.
Reference numeral 34 denotes a polygon mirror which passes laser light emitted from a laser light source (not shown) through an fθ lens 35 and is reflected by reflection mirrors 36, 37 and 38 to expose the photosensitive drum 29. 39 is the Boligon mirror 34, the reflection mirror 3
6, 37, 38, etc., are integrated into the uppermost frame 1c of the upper frame 1c.

Reference numeral 40 denotes a band electrode for charging the entire surface of the photosensitive drum 29, which is provided on a part of the upper frame 1c. Reference numeral 41 denotes a cleaning blade for transferring the image from the photosensitive drum 29 to the recording paper P and then cleaning the residual developer adhering to the surface of the photosensitive drum 29. The cleaning blade receives the cleaned developer and discharges it outside the cleaning unit. And a developer receiving member 42 for efficiently sending the developer scraped off by the cleaning blade to the transport device 43 is provided below the cleaning blade 41. The developer conveyed to the outside by the conveying device 43 is conveyed to the container 44 by the conveyor 45 so that a proper amount of the developer can be accumulated in the container 44 and can be removed and discarded. 46 is the developing device 30, 31, 32, 3
3 is a developer container for supplying the developer respectively, and the illustrated developer container is only one set, but four sets are provided side by side;
For example, cyan,
Magenta, yellow, and black color developers are supplied to perform color development. Reference numeral 47 denotes a manual feeder that can manually supply the recording paper P. The lower frame 1 and the upper frame 1c are assembled so that the conveyance path of the recording paper P can be released centering on the support shaft 1b. At least when the fixing device 19 is not reached, the upper frame 1c is released around the support shaft 1b, and the recording paper P can be taken out. Further, the recording paper P provided on the lower frame 1 is fed to another paper feeding device (not shown).
The guide plate 1a which can be supplied more is made.

The photosensitive drum 29 is provided on a frame 41a provided with the cleaning blade 41 via a support shaft 29a, and the support shaft 29a is supported by the upper frame 1c.

Using the above-described image forming apparatus, the photosensitive drum 29 was primary charged by the band electrode 40 by outputting an image signal for modulating the laser light source 35 from the host via a printer controller. Photoconductor drum 2
Image exposure is performed on nine surfaces.

Next, as a first color, the yellow color toner is developed by the developing device 30 and recharged by the band electrode 40.
After the second color image exposure is performed by the laser light source, the developing device 31 superimposes and develops the magenta color toner.

Thereafter, similarly, a cyan color toner as the third color and a black toner as the fourth color are sequentially superimposed and recharged image exposure and development are performed, thereby forming a four-color color toner image on the surface of the photosensitive drum 29. .

The gap between the photosensitive member and the developer carrier (hereinafter referred to as DS)
D) is 0.2 mm to 0.8 mm, and the developer is a two-component developer composed of a mixture of a carrier which is magnetic particles and a toner which is non-magnetic particles.

The weight average particle size of the carrier is
It is 15 to 80 microns, preferably 20 to 50 microns, and the weight average particle size of the toner is 5 to 20 microns. The developer is regulated on the developer carrier to a desired layer pressure by a layer pressure regulating means. It is desirable that the layer pressure is slightly smaller than the gap between the photosensitive member and the developer carrying member. The developer carrier is made of a conductor or a conductor having an insulating layer on the surface, and a DC or alternating (AC) electric field is applied between the developer carrier and the photoreceptor as a developing bias.

The toner image formed into an accurate color image by exposure control is sequentially charged, image-exposed, and developed on the surface of the rotating photosensitive drum 29 as described above. The toner image is transferred on the transfer belt 15 and fixed on the recording paper by the fixing device 19.

[0102]

As described above, according to the present invention, the following effects can be obtained. (1) With a simplified configuration, the quality of a color image can be improved. This makes it possible to provide a color image forming apparatus that achieves high image quality at low cost (small size). (2) In particular, by adopting a smoothing process for dynamically changing the position and size of a dot within one pixel, an improvement in apparent resolution, edge emphasis, contour emphasis, a moire reduction effect of halftone dots, and the like can be obtained. Image quality can be improved. (3) Further, the color reproducibility can be improved by employing the hue correction. (4) In the case where an image is formed by superimposing toners (developers) of different colors, a technique (smoothing processing) for dynamically changing the dot size and the dot position within one pixel with respect to the standard position is used. Effectively, it is possible to obtain effects such as improvement in apparent resolution, edge enhancement, contour enhancement, and reduction of halftone moire, and at the same time, accurate color tone reproduction in that case can be guaranteed. (5) The configuration can be simplified by employing the PWM control method. (6) By maximizing the image quality of both the monochrome image and the color image by utilizing the functions of the image forming apparatus by switching and executing the correction according to the special color of the monochrome image / color image. Can be. (7) Thus, it is possible to provide an image forming apparatus which is low cost, small in size, and achieves high image quality.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing the details of color correction used in the apparatus of FIG. 1;

FIG. 3 is a diagram showing the contents of a smoothing process (and a hue correction process) employed in the apparatus of FIG. 1;

FIG. 4 is a more detailed view of the embodiment of FIG. 1;

FIG. 5 is a timing chart for explaining the operation timing of the device of FIG. 4;

FIG. 6 is a diagram for explaining a combination of colors necessary to realize a seven-color multicolor image.

7 is a diagram showing a mechanism for inputting video (dot) data from the printer controller 3 to the printer main body 5 in the apparatus shown in FIG. 4 (FIG. 1).

FIG. 8 is a diagram showing the designation information of the dot printing position and dot size in FIG. 4 (FIG. 1) and the content of information AN indicating whether or not the edge corresponds to an edge.

FIG. 9 is a diagram showing an example of data stored in a register in FIG. 4 (FIG. 1).

FIG. 10 is a diagram showing an example of simplification of a write beam control mechanism.

FIGS. 11A and 11B are diagrams for explaining the characteristics of dot formation according to the present invention, in which a diagonal line of red (R = Y + M) is printed as an example. FIG. (B) shows a dot forming method for performing color tone correction on all dots with overlapping colors, including smoothing-processed dots, and (c) shows a smoothing process and color tone correcting process. The following shows a dot forming method for selectively using.

FIG. 12 is a diagram for explaining feature points in the case of dynamically changing the contents of hue correction in accordance with the level of the smoothing process, by summarizing the table format.

FIG. 13 is a diagram for explaining the contents of a smoothing process.

FIG. 14 is a diagram showing an internal configuration of the condition determination circuit 13 (particularly, a portion that realizes a function shown in a column (4) of FIG. 12) extracted from the configuration of FIG. 1;

FIGS. 15A and 15B are diagrams for explaining the contents of an example in which a smoothing process and an edge tint correction process are selectively used according to a single color mode and a color mode.

FIG. 16 is a diagram showing the contents of an example in which a smoothing process, an edge tint correction process, and a process in which the smoothing process and the edge tint correction process are combined are selectively used in one screen.

FIG. 17 is a diagram illustrating an example of the overall configuration of a color image forming apparatus (printer).

FIG. 18 is a diagram illustrating a configuration example of a main part of an apparatus (printer) that employs a process of forming a superimposed toner image by rotating a photosensitive drum a plurality of times during color image formation.

FIG. 19 is a diagram illustrating a configuration example of a main part of an apparatus that employs a belt transfer type color image forming process.

[Explanation of symbols]

 1 display 2 host computer 3 printer controller 4 operation board 5 printer body

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H04N 1/23 103 B41J 3/00 B // G03G 15/00 303 M (72) Inventor Masakazu Fukuchi Ishikawacho, Hachioji-shi, Tokyo 2970 Address Konica Corporation (72) Inventor Kiyoshi Kimura 2970 Address Ishikawacho, Hachioji-shi, Tokyo Tokyo (72) Inventor Hiroyuki Maruyama 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Yamaguchi Yasuhiko 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Kenji Taki 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Masaji Akamatsu 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Takao Kurohata 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (56) References JP-A-63 55570 (JP, A) JP flat 4-160869 (JP, A) JP flat 5-107861 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) H04N 1/40 - 1 / 409 H04N 1/23-1/23 103 G03G 13/01 G03G 15/01-15/01 117 B41J 2/44

Claims (9)

(57) [Claims] An electrophotographic color image forming apparatus for forming a color image on a recording medium by repeating a process of forming a toner image by charging, image exposure, and development with a color toner a plurality of times, comprising: Toner adhesion amount adjusting means for adjusting at least one of the toner adhesion amount of the color and the toner adhesion amount of the second color; and controlling at least one of the dot diameter and the dot position within one pixel. and, Ru improve apparent resolution flat
Comprising a smoothing processing means, the dots to be shape formed is, and determining the edge determination means whether the dots constituting the isolated dot or an edge, the toner adhesion amount adjusting means, the edge determination means The at least one of the first color toner image and the second color toner image using at least one of the result of the isolation or edge determination by the control unit and the control result of the smoothing processing unit. Color correction processing by adjusting the amount of adhesion
Performed, the color image forming apparatus characterized by. Wherein said toner adhesion amount adjusting means, the result of isolated or edge determination by the edge determination means, said flat
2. The color image forming apparatus according to claim 1, wherein at least one toner adhesion amount of the first color toner image and the second color toner image is adjusted using a control result of the smoothing processing unit as a parameter. apparatus. 3. The toner adhering amount adjusting means according to claim 1, wherein the result of the isolation or edge judgment by said edge judging means is smoothed.
2. The method according to claim 1, wherein the control unit adjusts at least one of the toner image of the first color and the toner image of the second color in preference to the result of the control of the conversion processing unit.
The color image forming apparatus as described in the above. 4. The smoothing means according to claim 1, wherein
The control result by the processing means is prioritized over the result of the isolation or edge judgment by the edge judgment means, and the toner adhesion amount of at least one of the first color toner image and the second color toner image is adjusted. The color image forming apparatus according to claim 1, wherein 5. An apparatus according to claim 1, further comprising a selection unit for selecting at least one of said edge determination unit and said smoothing processing unit.
The toner adhering amount adjusting unit calculates a toner adhering amount of at least one of the first color toner image and the second color toner image using a result obtained by the unit selected by the selecting unit. 2. The method of claim 1, wherein the adjusting is performed.
The color image forming apparatus as described in the above. 6. The smoothing processing means according to claim 1, wherein the first color toner image and the second color toner image have the same diameter. 2. The color image forming apparatus according to claim 1, wherein at least one of the devices is controlled. 7. The toner adhering amount adjusting means determines that the dot to be formed is an isolated dot or an edge dot by the edge determining means, and dynamically controls the diameter of the toner dot by the smoothing processing means for the dot. Is performed, the toner adhesion amounts of the first color and the second color increase in a direction in which the ratio of the toner adhesion amount of the first color to the toner adhesion amount of the second color increases as the dot diameter by the dynamic control decreases. 2. The color image forming apparatus according to claim 1, wherein the ratio is controlled. 8. An electrophotographic color image forming apparatus having a function of forming a color image on a recording medium by repeating a process of forming a toner image by charging, image exposure, and development with a color toner a plurality of times. Mode designation means for designating a single color mode / color mode; toner adhesion amount adjustment means for adjusting at least one of the first and second color toner adhesion amounts; and a toner dot within one pixel. And dynamic control of the diameter of the image to improve the apparent resolution, and edge determining means for determining whether the dot to be formed is an isolated dot or a dot constituting an edge. When the monochrome mode is designated by the mode designating means, smoothing is performed by the smoothing processing means, and the mode designation is performed. When the color mode is designated by the step, the toner image of the first color is used by using at least one of the result of the isolation or edge determination by the edge determination means and the result of the smoothing processing by the smoothing processing means. And performing a color correction process by adjusting at least one toner adhesion amount of the second color toner image. 9. An electrophotographic color image forming apparatus having a function of forming a color image on a recording medium by repeating a process of forming a toner image by charging, image exposure, and development with a color toner a plurality of times. A mode designating unit for designating a single color / color mode; a toner adhering amount adjusting unit for adjusting at least one of a first color adhering amount and a second color toner adhering amount; and one pixel Within, the smoothing processing means for dynamically controlling the diameter of the toner dots and improving the apparent resolution, and the edge judgment for judging whether or not the dots to be formed are isolated dots or dots constituting edges Means, when a single color mode is designated by the mode designation means, performs a smoothing process by the smoothing processing means,
Further, when the color mode is designated by the mode designating means, the smoothing process is not performed, and the result of the edge determination is used to select between the first color toner image and the second color toner image. A color image forming apparatus wherein at least one toner adhesion amount is adjusted.