JPH10336429A - Electronic photographic recorder and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in gradation reproducibility resulting from development of non-development dots between development dots at a density higher than an expected density due to the effect of proximity development dots with respect to a gradation image print by the dither method. SOLUTION: The recorder is provided with a driver 2 that divides received print data into data for a non-image area and data for an image area, a character binarization processing section 5 that binarizes the data for the non-image area, a comparator 7 that divides the data for the image area into data with a high density and data with a low density, a dither processing means 8 that binarizes the data with the high density, a dither processing means 9 that binarizes the data with the low density based on a dither matrix consisting of half tone cells whose size is smaller than those of the dither processing means 8, a frame buffer 6 that overlaps and stores the data outputted from the dither processing means 8,9, and a print section 3 that prints out an image based on the stored data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus, and more particularly, to an electrophotographic recording apparatus and method for binarizing a halftone image using a dither method.

[0002]

2. Description of the Related Art A conventional electrophotographic recording apparatus of this type is used for binarizing a halftone image to reproduce a gradation and for printing.

A conventional electrophotographic recording apparatus uses a printer driver that converts print data input from an application into a format that can be analyzed by a printer, and converts print data input from the printer driver into conditions such as the resolution of the printing unit and the data format. It has a controller that also converts and outputs the data, and a printing unit that prints an image based on print data output from the controller. The print data including the halftone image data input from the application is processed by the printer driver and the controller by the dither method.
A plurality of dots, for example, binarized with reference to a predetermined dither matrix composed of halftone cells composed of 12 dots, and by determining the development number to be developed among the dots constituting the halftone cell, for example, 13
The gradation of the gradation was reproduced. In this case, a pattern in which dots are close to each other may occur in an image to be printed.

[0004]

A first problem of the prior art is that if the dots determined to be developed by the dither method are close to each other, the non-developed dot portion between the developed dots is destroyed. If there is such a pattern portion in an image to be printed, the portion may be developed at a higher density than expected.

The reason will be described below with reference to the drawings.

FIG. 2 is a plan view showing a pattern for exposing the surface of the photoconductor, and FIG. 3 is a diagram showing an ideal electrostatic latent image on the line aa of the surface of the photoconductor exposed as shown in FIG. FIG. 4 is a graph showing the a-value of the photoreceptor surface exposed as shown in FIG.
FIG. 5 is a diagram illustrating an actual electrostatic latent image on the line a. Also,
FIG. 5 is a diagram showing an ideal printing result corresponding to the electrostatic latent image of FIG. 3, and FIG. 6 is a diagram showing an actual printing result corresponding to the electrostatic latent image of FIG.

If the distance between the two exposed portions is large, the amount of potential rise in the non-exposed portion between the two exposed portions is small and causes no problem. However, when the distance is one dot as shown in FIG. It is ideal that the photoconductor surface potential is high only in the exposed portion 34 and the exposed portion 35 as shown, and the photoconductor surface potential is ideally 0 in the non-exposed portion 36, but is actually adjacent as shown in FIG. Due to the characteristics of the photoconductor under the influence of the exposed part,
The potential of the non-exposed portion 39 also rises to some extent. As a result, ideally, the non-exposed portion is not developed as shown in FIG. 5 and the dots are ideally separated. However, as shown in FIG. 6, the non-exposed portion is also developed.

As a result, in a portion of the image to be printed where there is a pattern in which dots are close to each other as shown in FIG. 2, the dots between the dots to be developed are also developed, so that the density is higher than expected.

A second problem of the prior art is that in a low density area where the number of dots to be developed is small, a print result with a granular feeling is obtained.

[0010] The reason is that, in the low density area, a dot pattern is generally printed in each halftone cell, so that the dots are spaced apart from each other by the size of the halftone cell. This is because the print pattern is printed in a dotted manner.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tone control type electrophotographic printing which ensures high-precision tone reproducibility without undeveloped dots being crushed and developed at a density higher than expected. It is to provide a device.

It is another object of the present invention to provide a gradation control type electrophotographic printing apparatus which realizes a high quality printing result without graininess.

[0013]

According to the present invention, there is provided an electrophotographic recording apparatus comprising: an area dividing means (2 in FIG. 1) for dividing input print data into a non-image area and an image area; A character binarization processing unit (5 in FIG. 1) for binarizing the data in the non-image area output from 1) 2);
A data dividing means (7 in FIG. 1) for dividing the data of the image area output from the area dividing means (2 in FIG. 1) into data of a high density part and data of a low density part, and a data dividing means (FIG. 1) 7), the first dither processing means (8 in FIG. 1) for binarizing the data of the high density portion, and a halftone cell smaller in size than the first dither processing means (8 in FIG. 1). A second dither processing means (9 in FIG. 1) for binarizing the data of the low density portion output from the data dividing means (7 in FIG. 1) based on the dither matrix constituted by
A frame buffer (6 in FIG. 1) that stores the data output from the first dither processing means (8 in FIG. 1) and the data output from the second dither processing means (9 in FIG. 1) in an overlapping manner. ) And printing means (FIG. 1) for outputting an image based on the data stored in the frame buffer (6 in FIG. 1).
And 3).

With this configuration, the high density portion of the image area of the image to be printed is binarized based on a dither matrix composed of large halftone cells,
An image with good tone reproducibility can be obtained by increasing the number of expressible tones, and the low-density part is binarized based on a dither matrix composed of small halftone cells. Thus, an image without graininess can be obtained.

Further, the electrophotographic recording apparatus of the present invention has an area dividing means (FIG. 8-2) for dividing input print data into a non-image area and an image area, and an area dividing means (FIG. 8-2). A binarization processing unit (5 in FIG. 8) for binarizing the data in the non-image area output from the image processing unit, and data in the image area output from the area dividing unit (2 in FIG. 8). A data dividing means (7 in FIG. 8) for dividing the data into data and low density part data, and a first dither processing for binarizing the high density part data outputted from the data dividing means (7 in FIG. 8) 8 (FIG. 8) and data dividing means (FIG. 8) based on a dither matrix composed of halftone cells smaller than the first dither processing means (8 in FIG. 8).
7), the second dither processing means (9 in FIG. 8) for binarizing the data of the low density portion, the data output from the character binarization processing section (5 in FIG. 8), A first frame buffer (6 in FIG. 8) for storing the data output from the first dither processing means (8 in FIG. 8) in an overlapping manner, and an output from the second dither processing means (9 in FIG. 8). A second frame buffer (11 in FIG. 8) for storing the extracted data, and a printing means (FIG. 8) for separately developing images based on the data stored in the first and second frame buffers and then superimposing and outputting the images. 8-13), the first developing condition when the printing means (13 in FIG. 8) develops the data stored in the first frame buffer (6 in FIG. 8), and the printing means is the second frame buffer. Set the second development condition when developing the data stored in And having a developing condition setting unit for.

With this configuration, the optimum development conditions can be set in the low-density part in the printing of the low-density part without being influenced by the developing conditions optimally set in the printing of the high-density part in the image area of the image. Even if a halftone cell is used, it is possible to set such that it is hard to be crushed, and it is possible to obtain an image with good gradation reproducibility.

Further, the electrophotographic recording apparatus of the present invention has an area dividing means (FIG. 13-2) for dividing input print data into a non-image area and an image area, and an area dividing means (FIG. 13-2). A character binarization processing unit (5 in FIG. 13) for binarizing the data in the non-image area output from the image processing unit, and the image data in the image area output from the area dividing unit (2 in FIG. 13). A data dividing means (7 in FIG. 13) for dividing the data into low-density data, and a first dither processing for binarizing the high-density data output from the data dividing means (7 in FIG. 13) 13 (8 in FIG. 13) and data output from the data dividing means (7 in FIG. 13) based on a dither matrix composed of halftone cells smaller in size than the first dither processing means (8 in FIG. 13). Binary low density data Second dither processing means (13
9), and an arrangement control unit (25 in FIG. 13) that divides adjacent dots into two data and outputs the two data by the second dither processing means (9 in FIG. 13).
And the data output from the character binarization processing unit (5 in FIG. 13), the data output from the first dither processing means (8 in FIG. 13), and the data divided by the arrangement control unit (25 in FIG. 13). A first frame buffer (6 in FIG. 13) that stores the other data in an overlapping manner, and an arrangement control unit (6 in FIG. 13).
25), and a second frame buffer (11 in FIG. 13) for storing the other one of the data and an image based on the data stored in the first and second frame buffers are separately developed. It is characterized by having a printing means (13 in FIG. 13) for superimposing and outputting later.

With this configuration, even when a small halftone cell is used, there are no adjacent dots in the image data to be printed, so that the exposure potential is close to the ideal state, and an image with good tone reproducibility can be obtained. Can be.

[0019]

Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.

In a first embodiment of the present invention, a driver 2 for processing print data sent from an application 1
A printing unit 3 for printing, and a controller 4 for binarizing the print data sent from the driver 2 according to the resolution of the printing unit 3.

The print data sent from the application 1 is divided by the driver 2 into a non-image area and an image area. At this time, the image area is output by the driver 2 with 8 bits per pixel.

The divided print data is individually processed by the controller 4. The non-image area is binarized by the character binarization processing unit 5 in the controller 4, and then the binarized data is stored in the frame buffer 6 in the controller 4. The print data of the image area is classified into a high density part and a low density part by referring to 8-bit data for each pixel by a comparator 7 arranged in the controller 4.

Next, an operation of classifying print data into a high density portion and a low density portion by the comparator 7 will be described.

The comparator 7 reads the print data from the driver 2 for each pixel. In the print data, each pixel is 8-bit data. Next, the comparator 7
The threshold value of the low density part and the high density part is set to, for example, “1,000,000”.
0 ”= 128, and this is compared with the data read from the driver 2. If the numerical value is equal to or more than the threshold value, it is determined that the density is high, and if the value is less than the threshold, it is determined that the density is low. The configuration can be changed by referring to the value.Specifically, the following digital processing is performed: the read data is replaced with predetermined mask data “10000000”. Then, an AND process is performed on each bit, and then an OR process is performed on the 8-bit data after the AND process, wherein the OR process is performed if any one of the 8 bits is “1”.
The R processing result is “1”, and when all 8 bits are “0”, the OR processing result is “0”.

Then, it is determined whether the OR processing result is "1". If "1", the pixel is determined to be a high density portion, and the print data of the pixel is output to the high density portion data dither processing section 8. If it is not "1", the pixel is determined to be a low-density part, and the dither processing unit 9 for low-density part data
To output the print data of the pixel.

The data of the high-density portion and the low-density portion classified by the above operation are respectively provided by the dedicated dither processing unit 8,
9 is binarized individually. Here, each dither processing unit compares the threshold value of the dither halftone cell with the data bit, and outputs the comparison result as a binary signal. It is assumed that the size of the halftone cell in each dither processing unit is different, that the high density data is large and the low density data is small.

FIG. 7 is a diagram showing an example of a halftone cell used in the dither processing section 8 for high density part data. In FIG. 7, the halftone cell 14 is composed of 32 dots, and a threshold is set for each of these dots as shown in the figure. The 8-bit value of each dot of each pixel of the print data is compared with the corresponding threshold value of the halftone cell 14, and if the value is larger than the threshold value, the pixel is developed,
If the value is equal to or less than the threshold value, the number of dots to be developed is determined by not developing. Therefore, if the image area is binarized based on a dither pattern formed by repeatedly arranging the halftone cells 14, it is possible to reproduce 33 tones.

The threshold value is small at the center of the halftone cell 14 and large at the periphery thereof.
The image to be developed is often one dot print for one halftone cell. Therefore, if the halfton cell is made large, the interval between the dot prints to be printed becomes large, and the graininess deteriorates. On the other hand, a large halftone cell means that the number of dots constituting the halftone cell is large, so that the tone reproduction capability is enhanced. Conversely, if the halfton cell is made smaller, the interval between the dot prints to be printed becomes smaller, and a print result with less graininess can be obtained.

FIG. 8 is a diagram showing an example of a halftone cell used in the dither processing section 9 for low density part data. In FIG. 8, the halftone cell 15 is composed of twelve dots, the interval of one dot print for one halftone cell is reduced, and a print result with less graininess is obtained. Further, by determining the number of developments of these dots to be developed according to the threshold value set for each dot, it is possible to reproduce 13 gradations. The halftone cell is not limited to the one shown in the figure. Depending on the characteristics of the printing part, the halftone cell is set to a smaller one if the granularity of the printed image is strong, and conversely, it is large if there is a feeling that the number of gradation reproduction stages is insufficient. Can also be set.

The print data of the image area binarized by the dedicated dither processing sections 8 and 9 and the print data of the non-image area binarized by the character binarization processing section are superimposed in the frame buffer 6. Is stored. Finally, the printing unit 3 prints out an image based on the binarized data stored in the frame buffer 6.

With the above arrangement, the high density portion is formed as a large halftone cell so that the dots which are not developed are hardly broken, and an image having good tone reproducibility can be obtained by increasing the number of expressible tones. Can be done, and
The low-density portion can be an image without graininess by using a small halftone cell.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 9 is a block diagram of a second embodiment of the present invention. The second embodiment differs from the first embodiment in that a frame buffer 11 and a development condition setting unit 12 are added to the configuration in the controller 10. In FIG. 9, the data of the high density portion binarized by the dither processing section 8 is stored in the frame buffer 6. On the other hand, the data of the low density portion binarized by the dither processing section 9 is separately stored in the frame buffer 11. Further, a development condition setting unit 12 for setting development conditions of the printing unit 13 is added. Development condition setting unit 12
Each time one page of the binarized data stored in the frame buffer 6 or 11 is developed, the printing conditions and
For example, the developing bias is changed.

Further, in the second embodiment, the printing unit 13 forms an image of the binarized data stored in the frame buffer 6 and then converts the binarized data stored in the frame buffer 11 into an image. The third embodiment is also different from the first embodiment in that an image is formed by overlapping. FIG.
0 is a configuration diagram illustrating a configuration of the printing unit 13 according to the second embodiment of this invention.

In the printing unit 13 shown in FIG. 10, the exposure, development, and transfer processes are performed twice for printing one page, corresponding to the two frame buffers 6 and 11, respectively.

First, a latent image is formed on the photoreceptor 17 by exposing only the binarized data stored in the frame buffer 6 by the optical unit 20 and is developed by the developing roller 16. The toner image based on the binarized data of the frame buffer 6 developed on the surface of the photoconductor 17 is once transferred onto the intermediate transfer body 18. The toner image transferred onto the intermediate transfer body 18 is not immediately transferred to the paper 21 but is held on the intermediate transfer body 18.

Subsequently, a latent image is formed on the photosensitive member 17 by exposure to the binary data stored in the frame buffer 11 by the optical unit 20 in the same manner, and development is performed by the developing roller 16. At this time, the developing condition setting unit 12 sets the developing bias different from that when the binarized data stored in the frame buffer 6 is developed, and performs the developing. The toner image based on the binarized data of the frame buffer 11 developed on the surface of the photoreceptor 17 is transferred onto the intermediate transfer member 18 and superimposed. And
The superimposed toner image is transferred from the intermediate transfer member 18 to the sheet 21.
And a print output is obtained.

FIG. 11 is a configuration diagram showing another configuration of the printing unit 13 according to the second embodiment of the present invention. FIG.
As shown in FIG. 7, this embodiment has two exposure, development, and transfer processes, and has no intermediate transfer member. In this configuration, first, data in the frame buffer 7 is exposed, developed, and transferred by the printing unit 22. The data in the frame buffer 11 is exposed, developed, and transferred by the unit 23 with a delay of the paper traveling time, and the two images are superimposed on the paper. By adopting this form, there is no time to hold data until the image of one page is completely formed on the intermediate transfer member 18, so that there is an effect that the printing can be speeded up.

FIGS. 12 and 13 show changes in the printing state by changing the developing bias. FIG.
FIG. 13 is a diagram showing a developing bias potential when the printing result of FIG. 6 is obtained with respect to the electrostatic latent image of FIG. 4, and FIG. 13 is a diagram showing a developing bias potential when dot collapse is improved with respect to FIG. It is.

In FIG. 12, since the potential has risen to a level equal to or higher than the developing bias in the portion where the potential interference has occurred, an electric field is generated between the photosensitive member and the developing roller, so that the toner is developed. As shown in FIG. 1, dot collapse occurred.
By increasing as in 3, the generated electric field is eliminated, the toner is not developed in the portion where the potential interference has occurred, the dots are not broken, and therefore the density does not increase even in such a print pattern. .
Further, since the potential difference between the exposed portion and the developing bias is reduced, the amount of toner to be developed is reduced, and there is an effect that the resolving power is increased.

With the above configuration, the developing bias can be set in accordance with the interval between the halftone cells, so that the dots do not collapse and the density does not increase.

Next, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 14 is a block diagram of a third embodiment of the present invention. The third embodiment is different from the second embodiment in that an arrangement control unit 25 is added to the configuration in the controller 24.

In FIG. 14, the data of the high-density portion binarized by the dither processing section 8 is stored in the frame buffer 6.
On the other hand, the low-density data binarized by the dither processing unit 9 is further divided by the arrangement control unit 25 and separately stored in the frame buffer 6 and the frame buffer 11. The arrangement control unit 25 performs a process of dividing binarized data of dots that are likely to crush non-developed dots by interfering with each other into separate frame buffers.

FIGS. 15 to 18 are explanatory diagrams showing the operation of dividing the binarized data of dots which may possibly destroy non-developed dots by interfering with each other in the arrangement control unit 25 into separate frame buffers. .

In the arrangement controller 25, a filter 26 as shown in FIG. 16 is set. Filter 26
For example, data “0” is set with 2 × 2 dots as one block.
Alternatively, it is assumed that the blocks of “1” are arranged in a checkered pattern. The binarized image data generated by the dither processing unit 9 is, for example, image data 27 shown in FIG. First, the arrangement control unit 25 performs an AND process on the image data 27 with the filter 26 to obtain image data 28 as shown in FIG. The obtained image data 28 is stored in one frame buffer, for example, the frame buffer 6. Next, from the original image data 27 to the image data 2
8 is subtracted to obtain image data 29 as shown in FIG. The obtained image data 29 is stored in the frame buffer 11 different from the previous image data. In this manner, in the image data, the dots that may interfere with each other and destroy the non-developed dots are divided and stored in different frame buffers. Note that the filter 26 is connected to the printing unit 13.
It is preferable to set the optimum value in consideration of the resolution of the halftone cell and the shape of the halftone cell.

The print data divided and stored in the frame buffers 6 and 11 as described above are developed as separate images by the printing unit 13 and are superimposed.

Therefore, in the print data of the low density portion in the frame buffer 11, since the data of the adjacent dots is stored in the frame buffer 6 by the above-described procedure, the potential interference on the surface of the photosensitive member 17 occurs. Without this, ideal development can be realized.

Next, a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 19 is a block diagram of a fourth embodiment of the present invention. The fourth embodiment is different from the second embodiment in that the configuration in the controller 30 does not include the comparator 7, the dither processing unit 8, and the developing condition setting unit 12.

In FIG. 19, the print data of the image area input from the driver 2 to the controller 30 is not classified into a high density part and a low density part, and is binarized by the dither processing unit 9. The binarized data by the dither processing unit 9 is stored by the arrangement control unit 25 in such a manner that the binarized data of dots that may interfere with each other and crush non-developed dots are divided into separate frame buffers. You.

With this configuration, compared with the third embodiment, the process of dividing the high-density portion and the low-density portion and binarizing them by separate dither processing can be omitted, and the configuration is simple.
Without causing potential interference on the surface of the photoreceptor 17;
Development with excellent gradation can be realized.

In the above description, the print data of the image area is divided into two parts. However, the print data may be divided into three or more parts.

The halftone cells and filters are not limited to the examples shown in the description.
Any filter that functions as a filter may be used.

The printing apparatus for separately developing and superimposing two or more images is not limited to the configuration shown in the description, but may be any apparatus which separately develops and superimposes two or more images. Any printing device may be used.

As described above, the data of the image area of the input print data is divided into high density part data and low density part data and binarized. The high-density portion can be binarized based on a dither matrix having a smaller halftone cell than the density portion and the data obtained by superimposing the binarized values is printed.
Since the halftone cell is large, the dots that are not developed are not easily destroyed, the number of expressible gradations is large, and an image with good tone reproducibility can be obtained. An image without graininess can be obtained.

Further, the image is developed separately according to the interval between the halftone cells, and the developed toner images are superposed and output. Further, each image is developed under different developing conditions. With this configuration, it is possible to prevent the dot from being collapsed and to prevent the density from increasing.

Further, the print data of the low-density portion is further divided so that the data of the adjacent dots are stored in different frame buffers, and the respective data are separately developed, and the developed toner images are superposed. With this configuration, potential interference on the photoreceptor surface does not occur, and ideal development can be achieved for each one dot without being affected by the printing state of surrounding dots. Can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a pattern for exposing a charged photosensitive member surface when two dots are developed at an interval of one dot.

FIG. 3 is a view showing an ideal electrostatic latent image on the line AA of the surface of the photoconductor exposed as shown in FIG. 2;

FIG. 4 is a view showing an actual electrostatic latent image on the line AA of the surface of the photoconductor exposed as shown in FIG. 2;

FIG. 5 is a diagram illustrating an ideal printing result corresponding to the electrostatic latent image of FIG. 3;

FIG. 6 is a diagram illustrating an actual printing result corresponding to the electrostatic latent image of FIG. 4;

FIG. 7 is a diagram illustrating an example of a halftone cell used in a high-density part data dither processing unit 8;

FIG. 8 is a diagram showing an example of a halftone cell used in a dither processing unit 9 for low density part data.

FIG. 9 is a block diagram of a second embodiment of the present invention.

FIG. 10 is a configuration diagram illustrating a configuration of a printing unit 13 according to the second embodiment of this invention.

FIG. 11 is a configuration diagram illustrating another configuration of the printing unit 13 according to the second embodiment of this invention.

12 is a diagram illustrating a developing bias potential when the printing result of FIG. 6 is obtained for the electrostatic latent image of FIG. 4;

FIG. 13 is a diagram illustrating a developing bias potential in the case where dot collapse is improved with respect to FIG.

FIG. 14 is a block diagram of a third embodiment of the present invention.

FIG. 15 is a diagram illustrating an example of image data input to the arrangement control unit 25 of FIG. 14;

FIG. 16 is a diagram illustrating an example of a filter set in the arrangement control unit 25 of FIG. 14;

17 is a diagram illustrating one image data obtained by dividing the image data of FIG. 15 into two pieces in the arrangement control unit 25 of FIG. 14;

18 is a diagram illustrating another image data obtained by dividing the image data of FIG. 15 into two by the arrangement control unit 25 of FIG. 14;

FIG. 19 is a block diagram of a fourth embodiment of the present invention.

[Explanation of symbols]

 1 application 2 driver 3,13 printing unit 4,10,24 controller 5 character binarization processing unit 6,11 frame buffer 7 comparator 8,9 dither processing unit 25 placement control unit 26 filter 27,28,29 image data

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/403 H04N 1/40 103A

Claims (9)

[Claims] 1. An area dividing means for dividing input print data into a non-image area and an image area, and a binarization processing unit for binarizing data of the non-image area output from the area dividing means. Data dividing means for dividing the data of the image area output from the area dividing means into data of a high density part and data of a low density part, and converting the data of the high density part outputted from the data dividing means into binary data. Binarizing the data of the low density part output from the data dividing unit based on a first dither processing unit to be converted and a dither matrix composed of halftone cells smaller in size than the first dither processing unit; The second dither processing means, and the data output from the first dither processing means and the data output from the second dither processing means are stored in an overlapping manner. A frame buffer, electrophotographic recording apparatus characterized by having a printing means for outputting an image based on the stored in the frame buffer data. 2. An area dividing means for dividing input print data into a non-image area and an image area, and a binarizing processing unit for binarizing data of the non-image area output from the area dividing means. Data dividing means for dividing the data of the image area output from the area dividing means into data of a high density part and data of a low density part, and converting the data of the high density part outputted from the data dividing means into binary data. First dither processing means for converting the data of the low density portion output from the data dividing means based on a dither matrix composed of halftone cells smaller than the first dither processing means. Two dither processing means;
A first frame buffer for storing data output from the value processing unit and data output from the first dither processing unit in an overlapping manner, and storing data output from the second dither processing unit. A second frame buffer, a printing unit that superimposes and outputs the first and second images based on the data stored in the first and second frame buffers after separately developing the printing unit, A developing condition setting unit that sets a first developing condition when developing the first image and a second developing condition when the printing unit develops the second image, respectively. Electrophotographic recording device. 3. An area dividing means for dividing input print data into a non-image area and an image area, and a binarization processing unit for binarizing data of the non-image area output from the area dividing means. Data dividing means for dividing the data of the image area output from the area dividing means into data of a high density part and data of a low density part, and converting the data of the high density part outputted from the data dividing means into binary data. Binarizing the data of the low-density portion output from the data dividing unit based on a first dither processing unit to be converted and a dither matrix composed of halftone cells smaller in size than the first dither processing unit; A second dither processing means for dividing the data binarized by the second dither processing means into two data so that adjacent dots are separately processed. A first unit that stores the data output from the control unit and the binarization processing unit, the data output from the first dither processing unit, and one of the data divided by the arrangement control unit in an overlapping manner; A frame buffer, a second frame buffer storing the other one of the data divided by the arrangement control unit, and separately developing images based on the data stored in the first and second frame buffers. An electrophotographic recording apparatus, comprising: a printing unit that outputs an image after being superimposed later. 4. An area dividing means for dividing input print data into a non-image area and an image area, and a binarizing processing section for binarizing the data of the non-image area output from the area dividing means. Dither processing means for binarizing the data of the image area output from the area dividing means,
An arrangement control unit that divides adjacent dots into two data and outputs the data output from the dither processing unit, and data output from the binarization processing unit and one of the data divided by the arrangement control unit And a second frame buffer for storing the other data divided by the arrangement control unit, and an image based on the data of the first and second frame buffers. An electrophotographic recording apparatus, comprising: printing means for developing and developing the image and superimposing and outputting the resultant image. 5. A printing device comprising: a photosensitive member; a developing device for forming a toner image on the photosensitive member; an intermediate transfer member for holding the toner image; and an intermediate transfer member for transferring the toner image from the photosensitive member. A first transfer unit that transfers the toner image from the intermediate transfer body to a sheet, and a control unit that controls these units, and is stored in the first frame buffer. The toner image formed on the photoreceptor surface by the developing unit based on the data is transferred and held on the intermediate transfer body, and the developing unit based on the data stored in the second frame buffer. The toner image formed on the photoreceptor surface is transferred onto the intermediate transfer member holding the toner image, the toner images are superimposed, and the superimposed toner image is transferred from the intermediate transfer member to paper and output. mark 5. An electrophotographic recording apparatus according to claim 2, wherein said electrophotographic recording apparatus is printing means. 6. A developing condition setting unit for setting a developing condition of the printing unit, wherein the developing condition setting unit is configured to develop a first condition for developing the data stored in the first frame buffer by the printing unit. 6. The electrophotographic apparatus according to claim 3, wherein a developing condition and a second developing condition in which the printing unit develops data stored in the second frame buffer are set to different developing conditions. Recording device. 7. An area dividing step of dividing input print data into a non-image area and an image area; a binarizing step of binarizing data of the non-image area output from the area dividing step; A data dividing step of dividing the data of the image area output from the area dividing step into data of a high density part and data of a low density part, and binarizing the data of the high density part output from the data dividing step Binarizing the low-density portion data output from the data dividing step based on a first dithering step and a dither matrix composed of halftone cells smaller in size than the first dithering step. A second dithering step;
A combining step of superimposing data output from the first dithering step and data output from the second dithering step, and printing to output an image based on the data output from the combining step And an electrophotographic recording method. 8. An area dividing step of dividing input print data into a non-image area and an image area; a binarizing step of binarizing data of the non-image area output from the area dividing step; A data dividing step of dividing the data of the image area output from the area dividing step into data of a high density part and data of a low density part, and binarizing the data of the high density part output from the data dividing means A first dithering step, and a second step of binarizing the low-density data output from the data dividing step based on a dither matrix composed of halftone cells smaller than the first dithering step. A dithering step, a first combining step of superimposing data output from the binarizing step and data output from the first dithering step, A printing step of separately developing and outputting a first image based on the data output from the combining step and a second image based on the data output from the second dither processing step, and outputting A developing condition setting step of setting a first developing condition when developing the first image in a process and a second developing condition when developing the second image in the printing process. An electrophotographic recording method comprising: 9. An area dividing step of dividing input print data into a non-image area and an image area; a binarizing step of binarizing data of the non-image area output from the area dividing step; A data dividing step of dividing the data of the image area output from the area dividing step into data of a high density part and data of a low density part, and binarizing the data of the high density part output from the data dividing means Binarizing the low-density portion data output from the data dividing step based on a first dithering step and a dither matrix composed of halftone cells smaller in size than the first dithering step. A second dithering step;
An arrangement control step of dividing the data binarized by the second dither processing step into two data so that adjacent dots are separately processed; and A combining step of superimposing data output from one dither processing step and one of the data divided by the placement control step, and a first image and the placement control step based on the data output from the combining step A printing step of separately developing and superimposing and outputting the second image based on the other one of the data divided by the second image.