JP3666927B2 - Electrophotographic recording apparatus and facsimile apparatus using the same - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electrophotographic recording apparatus and a facsimile apparatus using the same.
[0002]
[Prior art]
Laser printers record on plain paper through four processes: charging, exposure, transfer, and fixing. Charging charges the surface of the photoreceptor with a positive charge or a negative charge. A positive charge is called forward development, and a negative charge is called reverse development. The exposure is performed by removing the charge with laser light. In the case of forward rotation development, the charge at the white pixel position is removed. In the case of reversal development, the charge at the position that becomes the black pixel is removed. In the transfer, the toner is attached to the position of the black pixel, and the toner is attached to the remaining positive charge that is not removed by the forward development to represent the black pixel, and in the reverse development, the toner is removed by the irradiation. Toner adheres to represent black pixels. Transfer is a process of attaching toner representing black pixels to plain paper, and fixing is a process of heating and fixing the adhered toner. In the following description, the case of reversal development will be described, but it can also be applied to normal rotation development.
[0003]
The black area ratio is defined as representing the state of toner adhesion to black pixels. This is a value indicating the ratio of toner adhering to the black pixel area of one dot, and is 100% if all the toner adheres to one dot, and 50% if the toner adheres to half the area of one dot. . In the reversal development, since the charge in the range irradiated with the laser is removed and the toner adheres thereto, the laser irradiation rate is equal to the black area rate. A laser irradiation rate is a value which shows the ratio of the area actually irradiated with respect to the irradiation area of 1 dot.
[0004]
Printing includes a character image portion (including a pattern portion) and a solid black image portion. In the solid black image portion, the black area ratio is approximately 100%. This is because, in the case of solid black, it stands out when the white part is mixed. On the other hand, the character image portion can obtain a relatively clear print result even when the black area ratio is 100% or less, for example, 40 to 60%.
[0005]
[Problems to be solved by the invention]
Conventionally, when toner is attached to a black pixel, the toner is uniformly attached to the area of the black pixel without distinguishing between a character image and a solid black image. That is, the black area ratio was set to 100%. For this reason, the toner consumption is large.
The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the toner consumption by reducing the black area ratio to 100% or less for character image portions and the like.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided identification means for identifying the type of page unit data to be recorded, and the black area of the page unit black pixel data in accordance with the type of page unit data identified by the identification means. A first control means for setting a rate; a discrimination means for discriminating the number of black pixels of the predetermined surrounding data for each page unit black pixel data; and a target according to the number of black pixels of the predetermined ambient data determined by the discrimination means And second control means for setting the black area ratio of the page unit black pixel data set by the first control means for each black pixel data to a predetermined black area ratio .
[0007]
According to a second aspect of the present invention, in the first aspect of the invention, the identifying means determines whether the page unit data is at least received data, binary or halftone read data, or a report list indicating a management state of the apparatus. The first control means sets the black area ratio in the case of binary read data or report list to be smaller than the black area ratio in the case of received data or halftone read data, and the second control means The black area ratio when the surrounding data is not all black pixels is set to be smaller than the black area ratio when the predetermined surrounding data is all black pixels .
[0014]
[Action]
According to the first aspect of the invention, the type of page unit data to be recorded is identified, and the black area ratio of page unit black pixel data to be recorded is set according to the type of page unit data. As a result, the sharpness varies depending on the type of page unit data, so the consumption of toner to be recorded for each page unit data can be reduced by changing the black area ratio of black pixels so as to have substantially the same sharpness. it can. Further, the black area ratio of the page unit black pixel data is set to a predetermined black area ratio for each target black pixel data in accordance with the number of black pixels of the predetermined surrounding data for each black pixel data. Thereby, even if the black area ratio is set according to the image determined by the number of black pixels of the predetermined surrounding data for each black pixel data, the consumption of the toner to be recorded can be reduced without reducing the sharpness of the image. it can.
[0015]
According to the invention of claim 2, the black area ratio when the page unit data is binary read data or report list is set to be smaller than the black area ratio when received data or halftone read data. As a result, the sharpness differs between the binary read data or report list and the received data or halftone read data. Therefore, the black area ratio of the black pixels is changed so that the same sharpness is obtained for each page unit data. It is possible to reduce the consumption of toner to be recorded. Further, the black area ratio when the predetermined surrounding data is not all black pixels is set smaller than the black area ratio when the predetermined surrounding data is all black pixels. As a result, the consumption of toner to be recorded without reducing the sharpness of the image even if the black area ratio of the image judged by the number of black pixels of the predetermined surrounding data for each black pixel data is reduced for the character image portion, etc. Can be reduced.
[0022]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of this embodiment, and shows a case where it is provided in a facsimile apparatus. The transmission control unit 1 is connected to a line and controls transmission of data to be transmitted / received. The codec processing unit 2 decodes the received data to obtain the original data, and encodes the data to be transmitted. The document reading unit 3 reads a document with a scanner and outputs it as image data. When the data read by the document reading unit 3 is recorded by the recording unit 8 or stored in the memory 6 and sent to the codec processing unit 2 and sent to the line, the switch 4 keeps the received data encoded. When the data is once stored in the memory 6 and recorded, it is switched from the memory 6 to the codec processing unit 2 for decoding and printing by the recording unit 8, and the control unit 5 controls the switching of the switch 4. . The recording I / F processing unit 7 controls the black area ratio of black pixels input to the recording unit 8. The recording unit 8 prints the received data and the read data.
[0023]
FIG. 2 is a block diagram showing a configuration of the recording I / F processing unit 7.
The data input unit 11 inputs read data from the document reading unit 3 and decrypted data from the codec processing unit 2. The data processing unit 12 outputs the black pixel generation timing of the input data. The register 13 is a register for setting the black area ratio of black pixels. The irradiation rate timing generator 14 generates the timing set by the register 13. The AND gate 15 takes the logical product of the outputs of the data processing unit 12 and the irradiation rate timing generation unit 14 and outputs the logical product as timing data of the laser irradiation rate from the data output unit 16 to the recording unit 8.
[0024]
FIG. 3 shows output waveforms of the data processor 12, the irradiation rate timing generator 14, and the AND gate 15. Waveform A represents the black pixel generation timing, waveform B represents the timing for achieving the set black area ratio, and C represents the logical product of A and B. The black area ratio can be set to an arbitrary value by changing the setting value of the register 13. FIG. 3 shows a case where the black area ratio is set to 50%.
[0025]
In FIG. 4, the sharpness differs between the data received from the outside and the read data generated from the inside. Fig. 4 shows a flow diagram for reducing consumption. When there is a recording request (S1), it is checked whether the data to be recorded is reception data or halftone with read data (S2). If the reception data or read data is halftone data, the laser irradiation rate is set to m. %, For example, 60% is set (S3). The setting is made in the register 13 of FIG. 3 with a black area ratio of 60%. If the read data is read by the original reading unit 3 instead of the received data and is read as binary image data (S4), the laser irradiation rate is set to n%, for example, 40% (S6). In the case of a report list indicating the management status of the facsimile machine (S5), the laser irradiation rate is set to n% (S6). In this way, the laser irradiation rate is set and one page is recorded (S7). Note that n <m is set. Since the black area ratio is set according to the type of data to be printed in this way, the toner consumption can be reduced.
[0026]
FIG. 5 is a diagram showing a method of setting the black area ratio of a black pixel by white pixels of predetermined surrounding pixels of the black pixel. Each square area represents a pixel, a pixel with a black circle represents a black pixel, and a pixel without a black circle represents a white pixel. The hatched area excluding the center is a predetermined peripheral pixel, and the center pixel is the pixel for setting the black area ratio. (A) is a case where the surrounding pixels are all solid black pixels. In this case, the black area ratio of the pixels is, for example, 100%. (B) and (C) include white pixels in the surrounding pixels. The right side of the pixels is a black pixel, and the black area ratio is, for example, 60%. (D) is a case where the right side of the pixel is a white pixel, and the black area ratio of the pixel is, for example, 40%. When the pixel on the right side of the pixel is a white pixel, the black area ratio is decreased because the black pixel ends at the position of the pixel and moves to the white pixel. This is because there is little decrease in sharpness. Note that main scanning is performed from left to right.
[0027]
FIG. 6 is a flowchart for determining the black area ratio shown in FIG.
The recording process is started (S10), and the pixel that is a black pixel and the surrounding eight pixels are detected (S11). Whether all the surrounding pixels are black pixels is checked (S12). If all the surrounding pixels are black pixels, the laser irradiation rate is set to L%, for example, 100%. If the surrounding pixels include a white pixel but the right side of the pixel is a black pixel (S14), the laser irradiation rate is set to M%, for example, 60% (S15). When the right side is a white pixel (S14), the laser irradiation rate is set to N%, for example, 40% (S16). Recording is started at the laser irradiation rate thus set (S17). As a result, the black pixel area ratio is 100%, but the black pixel area ratio is 60% or 40%, which is less than this, so the toner consumption is reduced. When the surrounding pixels are all solid black, the laser irradiation rate is set to 100%, but even if it is set to 90%, the sharpness is not affected so much. As a result, toner consumption can be reduced. When the black area ratio is 0%, the black pixel can be a white pixel, and the inventions of claims 5 and 6 can be easily implemented.
[0028]
Next, processing when black pixels to be exposed are continuously arranged in the main scanning direction will be described. FIG. 7 shows processing when there are three black pixels in the main scanning direction. FIG. 7A shows a case where three black pixels are continuous in the main scanning direction, and FIG. 7B shows a case where the right black pixel is white and the number of black pixels is two. In this case, the left black pixel may be white. FIG. 8 shows a process when there are four or more black pixels continuously in the main scanning direction. FIG. 8A shows a case where five black pixels are continuous in the main scanning direction, and FIG. 8B shows a case where the black pixels at both ends are white. In this case, only one of the left and right may be white. By performing such processing, the amount of toner used can be reduced without degrading the definition. Note that the method of determining the black area ratio of the black pixels described in FIG. 5 by the surrounding pixels and the method shown in FIGS. 7 and 8 may be performed by selecting only one of the processes. If both compete for the same target, the method of FIG. 5 may be preferentially performed.
[0029]
A flowchart of this process will be described with reference to FIG.
[0030]
As shown in FIG. 5, the surrounding pixels for the target pixel are particularly viewed using a 3 × 3 matrix (S21). At this time, it is determined whether or not surrounding pixels other than the main scanning direction are white pixels (S22). When it is confirmed that all the pixels are white pixels, the number of continuous black pixels in the main scanning direction is counted (S23). Whether the counted number is two or less, three, four or more is determined (S24, S25, S26), and if it is two or less, nothing is done and the processing described in FIG. 5 is continued (S36). If it is three, it is confirmed whether surrounding pixels other than the main scanning direction at both ends are white pixels (S32). If the surrounding pixels other than the main scanning direction at both ends are black pixels, no processing is performed. If one of the surrounding pixels is a white pixel, its end is set as a white pixel (S33, S34, S31). If peripheral pixels other than the main scanning direction at both ends are white pixels, an arbitrary end is set as a white pixel (S34, S35).
[0031]
If the number of consecutive pixels is 4 or more in S26, it is confirmed whether surrounding pixels other than the main scanning direction at both ends are white (S27), and surrounding pixels other than the main scanning direction at both ends are black pixels. Then, no processing is performed, and if one of the surrounding pixels other than the main scanning direction is a white pixel, the end thereof is set as a white pixel (S28, S29, S31). If surrounding pixels other than the main scanning direction at both ends are white pixels, both ends are set as white pixels (S30).
[0032]
In this way, on the condition that peripheral pixels other than the main scanning direction at both ends of the continuous black pixels are white pixels, the pixels at either one end are set as white pixels. When the surrounding pixels other than the main scanning direction of the black pixels at both ends are not white pixels, processing for setting the white pixels is not performed. For this reason, two types of image processing can be performed without disturbing the image, and toner consumption can be suppressed.
[0033]
【The invention's effect】
As is apparent from the above description, the present invention identifies the type of page unit data to be recorded and sets the black area ratio of page unit black pixel data to be recorded according to the type of page unit data. As a result, the sharpness varies depending on the type of page unit data, so that the black area ratio of black pixels is changed to reduce the consumption of toner to be recorded for each page unit data so as to obtain substantially the same sharpness. it can. Further, the black area ratio of the page unit black pixel data is set to a predetermined black area ratio for each target black pixel data in accordance with the number of black pixels of the predetermined surrounding data for each black pixel data. As a result, even if the black area ratio is set according to the image determined by the number of black pixels of the predetermined surrounding data for each black pixel data, the consumption of toner to be recorded can be reduced without reducing the sharpness of the image. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment. FIG. 2 is a block diagram showing a configuration of a recording I / F processing unit. FIG. 3 is a timing chart of the recording I / F processing unit. Flow diagram for determining the laser irradiation rate [FIG. 5] Explanatory diagram for setting the black area ratio by the surrounding pixels of the pixel. FIG. 6: Operation flow chart for setting the black area ratio by the surrounding pixels of the pixel. FIG. 8 is a diagram for explaining processing when three pixels are continuously arranged in the main scanning direction. FIG. 8 is a diagram for explaining processing when four or more black pixels are continuously arranged in the main scanning direction. Flow diagram when multiple black pixels continue in the main scanning direction [Explanation of symbols]
2 Codec processing unit 3 Document reading unit 6 Memory 7 Recording I / F processing unit 8 Recording unit

Claims (2)

Identifying means for identifying the type of page unit data to be recorded; first control means for setting a black area ratio of page unit black pixel data in accordance with the type of page unit data identified by the identifying means; Setting means for determining the number of black pixels of the predetermined surrounding data for each black pixel data, and setting by the first control means for each target black pixel data according to the number of black pixels of the predetermined surrounding data determined by the determining means An electrophotographic recording apparatus comprising: a second control unit that sets a black area ratio of the page unit black pixel data to a predetermined black area ratio . The identification means determines whether the page unit data is at least received data, binary or halftone read data, or a report list indicating the management status of the apparatus, and the first control means is binary read data or report The black area ratio in the case of the list is set smaller than the black area ratio in the case of the received data or the halftone read data, and the second control means sets the black area ratio when the predetermined peripheral data is not all black pixels to the predetermined peripheral area. 2. The electrophotographic recording apparatus according to claim 1, wherein the data is set to be smaller than a black area ratio when all data is black pixels .

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