JPH0823454A - Image forming device - Google Patents

Abstract

PURPOSE:To attain substitute prints without stopping image processing even when a desired development agent is not available by converting print data of a development agent not available into print data of other development agent available and printing out data by the other development agent when at least one color development agent of plural colors is not available. CONSTITUTION:A print processing unit 12 provides an output of a print request signal PAGE to a printer controller 11. When print is enable, the controller 11 provides an output of a reply signal PAGAK to the processing unit 12 to inform that the print data are receptible. After the controller 11 outputs a vertical synchronizing signal VSYNC and a horizontal synchronizing signal HSYNC to each plane (print plane of each color), the processing unit 12 provides an output of print data VIDEO. When no yellow development agent is available, it is informed from the controller 11 to the processing unit 12 by serial communication 21. The processing unit 12 converts print data of the development agent not available into print data of other available development agent and printing is made by the other development agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a developing device for a plurality of colors and capable of printing a single color or a plurality of colors.

[0002]

2. Description of the Related Art In recent years, a laser beam printer as an image forming apparatus has been widely used as a printing apparatus, and such a laser beam printer is also being colorized. 2. Description of the Related Art Conventionally, a laser beam printer using an electronic process has a plurality of developers, and sequentially forms toner images from the first color, and then superimposes them to perform image recording of multicolor printing.

By the way, in the above laser beam printer, when an image is formed, if there is no developer of a designated color, the image forming operation is stopped. Therefore,
When there is no developer of the designated color, it is possible to print using a developer of another color. In addition, JP-A-62-1
As disclosed in Japanese Laid-Open Patent Publication No. 236254, when a developer of a designated color is not printed in printing of a plurality of colors, the dot size of another color is changed and printing is performed, so that the color designation and the other color There is one that can be distinguished from the print of.

[0004]

However, in the above-mentioned device, by changing the dot size, it is possible to perform the distinguishable printing from the printing requiring the color designation.
There is a problem that faithful halftone reproduction printing cannot be performed.

Although it is a color printer, monochrome monochromatic printing is considered to be frequently used for document creation and the like.
If printing is not possible because there is no developer of the specified color (black in this case), it causes a significant deterioration in function. However, black printing can be realized by using, for example, three colors of yellow, magenta, and cyan, and thus substitute printing is possible.

In the present invention, even if the developer of the designated color does not exist, the printing of the substitute color is performed at the same time as the printing of the intermediate color is replaced with the gradation printing of the single color so that the printing operation is not stopped. It is an object of the present invention to provide an image forming apparatus in which the substitute printing can be easily viewed.

[0007]

In order to solve the above-mentioned problems, an image forming apparatus according to a first aspect of the present invention has developers of a plurality of colors and has a plurality of colors based on print data for each color. In an image forming apparatus that performs printing by performing development using the other developer, when there is no developer of at least one color among a plurality of colors, printing data of another developer that does not exist is printed. A printing control unit for converting the data into data and printing with another developer is provided.

According to a second aspect of the present invention, in the image forming apparatus according to the second aspect, the developers of a plurality of colors are yellow, magenta, cyan and black, and at least one of the yellow, magenta and cyan developers is used. When there is no color developer, the print control means for converting the print data of yellow, magenta, and cyan into black print data and performing printing using only the black developer according to the converted print data is provided. .

An image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the first aspect, in which printing is represented by a plurality of dots, and the dot size of the converted print data is used as the print data. It is provided with a conversion means that changes according to the change, for example, a laser light intensity modulator or a pulse width modulator.

[0010]

According to the structure of claim 1, in an image forming apparatus having a plurality of color developers, and performing printing by developing with a plurality of color developers based on print data for each color. When the developer of at least one color out of the plurality of colors does not exist, the print control means converts the print data of the non-existent developer into the print data of the other existing developer, and the printing is performed by the other developer. Be done. Therefore, even when the developer of the desired color does not exist, the substitute printing with another color is performed without stopping the image forming operation.

According to the second aspect of the invention, the developers of plural colors are yellow, magenta, cyan and black, and at least one of the yellow, magenta and cyan developers is present. If not, the print control unit converts the print data of yellow, magenta, and cyan into black print data, and performs monochromatic substitute printing using the black developer.

According to the third aspect of the invention, when the halftone reproduction with a plurality of colors is performed, the dot size can be changed according to the halftone data of the non-existing colors of the constituent colors. Therefore, a halftone color is expressed by the change in the dot size, and the gradation can be excellently reproduced even with a single color.

[0013]

【Example】

[First Embodiment] The first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the color laser beam printer which is the image forming apparatus of the present invention is capable of color printing in yellow, magenta, cyan, and black, and 1Y and 1M corresponding to the respective colors. , 1
Four developer units C and 1K are arranged in the vicinity of the photosensitive drum 9 so as to surround the periphery thereof. Around the photosensitive drum 9, a charging unit 8 for charging the photosensitive drum 9 and a transfer drum 5 for transferring a toner image formed on the photosensitive drum to paper.
Further, a cleaning unit 7 for removing the toner remaining on the photoconductor 9 after the transfer is provided. further,
Above the photosensitive drum 9, an optical unit 10 for generating a laser signal according to print data, a fixing unit 6 for fixing the toner image transferred on the paper, and a discharge tray for discharging the paper after the fixing. 17 are provided. Further, a separation claw 16 for separating the paper from the transfer drum is provided between the transfer drum 5 and the fixing unit.

A paper feed tray 3 and a paper feed cassette 2 are provided below the laser printer. The paper from the paper feed tray 3 or the paper feed cassette 2 is transferred to the transfer drum 5 by the paper feed unit 4 and the conveyance roller 20. To be sent to.

The laser printer includes an external device 13
A print processing device 12 (print control means) and a printer control device 11 for reading the print data created by the above and converting it into a laser signal are provided.

Next, the printing process in the above color laser printer will be described.

First, the PDL created by the external device 13
The print data such as (page description language) is printed by the print processing device 1.
2 is input via the interface 14. The input print data is processed by the print processing device 12 and is sent to the printer control device 11 as the processed print data, here, as a VIDEO signal. The printer controller 11 uses the laser ON / O to send the sent print data.
It is converted into an FF signal and output to the optical unit 10 of the printer, and according to the laser signal 18 from the optical unit 10,
A latent image is formed on the photosensitive drum 9. The surface of the photoconductor drum 9 is previously charged by the charging unit 8. On the other hand, paper is supplied by the paper feeding unit 4 from the paper feeding cassette 2 or the paper feeding tray 3.

At this time, yellow, magenta, cyan,
In the case of monochrome printing of any one color of black, the developer of a desired color adheres to the photosensitive drum 9 according to the latent image on the photosensitive drum 9, and a toner image is formed. When the paper passes between the transfer drum 5 and the photoconductor drum 9, the image is transferred onto the paper, fixed by the fixing unit 6, and then output to the paper discharge tray 17 outside the main body to complete the printing. . The developer remaining on the photoconductor drum 9 is removed by the cleaning unit 7, and the process proceeds to the next process.

Next, in the case of mixed color printing of two or more colors of yellow, magenta, cyan and black, first the developer of the first color is attached onto the photosensitive drum 9, and the paper is transferred onto the transfer drum 5 and the photosensitive member. The image is transferred onto the paper as it passes through the drum 9. Then, the paper is adsorbed to the transfer drum 5, and the transfer process is performed again. In that case,
The developer of the second color is formed as an image on the photosensitive drum 9, and when the paper passes between the transfer drum 5 and the photosensitive drum 9, the image is transferred so as to be superimposed on the image of the first color on the paper. To be done. The same process is repeated for the third and subsequent colors, and when the development and transfer of all colors are completed, the paper is separated from the transfer drum 5 by the separation claw 16 and fixed by the fixing unit 6, and then the paper discharge tray 17 outside the main body. Is output to and printing ends.

Next, the timing of print data will be described with reference to FIGS.

As shown in FIG. 2, the print processing device 12 includes
First, a print request signal PAGE is output to the printer control device 11. On the other hand, when printing is possible, the printer control device 11 outputs a response signal PAGAK to the print processing device 12 to notify that print data can be received. After that, the printer control device 1
The vertical synchronizing signal VSYNC for each plane (printing surface for each color) from 1 is output to the print processing device 12, the top margin is counted based on the signal, and the left margin is also counted based on the horizontal synchronizing signal HSYNC. Then, the print processing device 12 outputs VI as print data.
The DEO signal is output.

As shown in FIG. 3, yellow, magenta,
VIDEO signals corresponding to cyan and black are sequentially output, and the above-described processes are performed accordingly.

Here, in the case of printing color data, the reproduction of the intermediate color is performed by being separated into the data of each color component, but at least one developer, for example, the yellow developer unit 1Y becomes empty. If the yellow developer does not exist due to the above reason, the printer controller 11 notifies the print processor 12 that there is no developer by the serial communication 21.

At this time, the following three types of processing can be considered as the processing performed by the print processing device 12. That is, an error message is issued, and printing is disabled until the error is canceled, such as replenishing the developer.
A component without a developer, here, yellow is output without printing. Based on the data (4 values) of each component, the gradation data of a single color, for example, black is replaced and printed.

This embodiment is a case where the above is selected,
This will be described next.

The print processing device 12 is, as shown in FIG.
Interface unit 22, central processing unit 23, memory 2
4, an internal storage device 25 and a print data output unit 26. The print data from the external device 13 is input to the interface unit 22 and then the central processing unit 23.
5 in the internal storage device 25.
It is developed as shown in (c). Incidentally, FIG. 5B shows a state of development when the above processing is performed, where Y, M, C, and K are image data of respective components of yellow, magenta, cyan, and black. Is represented.

The print data sent to the central processing unit 23 and processed is basically developed into four components as shown in FIG. 5 (a). Based on this 4-valued data, for example, 4
A basic grid of × 4 is set, and a table for conversion according to the ratio of each component is provided in advance. This example will be described below with reference to FIG.

For each color of yellow, cyan and magenta, black is considered as a reference at 16 levels, and weights of 4, 8 and 12 are given as shown in Tables 1 to 3 below. However, for this weighting, yellow,
Based on the relative density of each color of cyan and magenta with respect to the density of black, it is determined to an appropriate level according to the characteristics of the process device, such as the developer or the photoconductor (the density of each color is the density of black. The number of dots when replaced with), and the above value is used here for convenience.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

Next, according to the table, the number of dots per one grid after conversion is defined according to the number of dots existing in the 4 × 4 grid. An example is shown in FIG. Although the arrangement of dots after conversion is not specified, it is defined so that the dots are distributed almost uniformly. This table data is stored in the read-only memory 24 shown in FIG. Here, as described above, for each color of Y, C and M,
After weighting the levels of 4, 8, and 12 and then converting, as shown in FIG. 7, the respective data are superposed to leave at least a portion having at least one dot, resulting in a black dither pattern. Obtain data (black gradation data). The generated data is the print data output unit 2
It is output to the print control device 11 by 6.

The control flowchart of this embodiment will be described below with reference to FIGS.

First, when performing printing, the print processing apparatus 1
A print request signal PAGE is sent from 2 to the printer controller 11 (S1). If the print request signal PAGE is 0, it is determined that printing is performed, and the yellow process flag Y
The PF, the magenta process flag MPF, the cyan process flag CPF, and the black process flag KPF are set to 1, and the black single-color print flag KTF is set to 0.
(S2).

Next, it is judged whether or not the yellow developer is present (S3). If not, the process proceeds to the yellow developer-less process (S4) described below. If there is a yellow developer, the presence or absence of a magenta developer is determined (S5). If there is no magenta developer, the process proceeds to the magenta developer-less process (S6) described later.
If the magenta developer is present, it is determined whether or not the cyan developer is present (S7). If there is no cyan developer, the process proceeds to cyan developer-less processing (S8) described later. If you have a cyan developer,
The presence / absence of the black developer is determined (S9). If there is no black developer, the black developer-less process (S1
Move to 0). If there is a black developer, the printing process is performed (S11).

If there is no yellow developer in S3, as shown in FIG.
PF is set to 0 (S21), and the fact that there is no yellow developer is displayed on the LCD or the like (S22). After that, it is determined whether or not the printing is continued (S23). If the printing is not continued, the process returns to the start (S24), and if the printing is continued, it is determined whether or not the black monochromatic printing is performed (S25). When performing black monochromatic printing, the black monochromatic printing flag KTF
Is set to 1 (S26), conversion is performed as described above, and black gradation data and a dither pattern are obtained (S2).
7).

If there is no magenta developer in S5, as shown in FIG. 10, first, the magenta process flag MPF is set to 0 (S31), and the absence of magenta developer is displayed on the LCD or the like (S32). After that, it is determined whether or not to continue printing (S33), and if not continued, the process returns to the start (S34), and if continued, KTF is 1
It is determined whether or not is set (S35).

When KTF is set to 1, that is, when there is no yellow developer and it is instructed to perform black monochromatic printing, magenta data is unconditionally converted into black gradation data (S38). On the other hand, if KTF is not set to 1, it is determined whether or not black monochromatic printing is to be performed (S36). If black monochromatic printing is to be performed, the black monochromatic printing flag KTF is set to 1 (S37). The magenta data is converted into black gradation data (S38).

If there is no cyan developer in S7,
As shown in FIG. 11, no magenta data processing (S6)
The same processing (S41 to S48) is performed to obtain black gradation data.

In S9, when there is no black developer, as shown in FIG. 12, it is first judged whether KTF is 1 (S51), and if it is 1, it means that printing is impossible. It is displayed to inform the user (S52), and the printing operation is finished. On the other hand, if KTF is 0, the printing is normal, so KPF is set to 0 (S53) and the process returns.

In the printing process in S11, as shown in FIG. 13, it is first determined whether KTF is 1 (S6).
1). If it is 1, after the black gradation data obtained in the processing when there is no developer for each color is combined (S62), the black printing process is executed based on the obtained black gradation data (S70). Also, KTF
If is not 1, it is determined whether YPF is 0 (S6).
3).

If YPF is not 0, the aforementioned yellow color printing process is executed (S64), and if YPF is 0, then it is determined whether MPF is 0 or not (S65). MPF is 0
If not, the magenta color printing process described above is executed (S
66), if MPF is 0, it is further determined whether or not the next CPF is 0 (S67). If CPF is not 0, the cyan printing process described above is executed (S68). If CPF is 0, it is determined whether KPF is 0 (S69), and KP
If F is 0, the process returns to the original process, and if KPF is not 0, the black printing process is executed (S70).

As described above, when at least one developer does not exist when performing color printing, the color intermediate color is replaced by the gradation data of black by performing conversion using the data input in advance. Is possible.

In this embodiment, yellow, magenta,
We have shown the process to perform monochrome printing with black developer when there is no cyan developer. In addition, we perform monochrome printing with yellow, magenta or cyan developer when there is no black developer. You may do it. In this case, in the black developer-less processing S10, if KTF is 1 in S51, the above monochromatic printing is performed.

[Embodiment 2] The following description will discuss Embodiment 2 of the present invention with reference to FIGS. 1, 2, 4, 14, and 15. In order to simplify the explanation,
The members having the same functions as those in the above-mentioned embodiment are given the same member numbers, and the description thereof is omitted.

Each of the Y, M, C and K colors created based on the color data sent from the external device 13 has a certain halftone level. By combining each color according to the level, an intermediate color is generated. At this time, if there is no one-component developer,
Printing becomes impossible or a desired intermediate color cannot be obtained, which results in printing.

Therefore, in the present embodiment, printing is performed by substituting a single color, for example, a gradation level of black.
Gradation printing is performed by changing the dot size by adjusting the exposure time by intensity modulation or pulse modulation of a laser beam as a printing means.

The laser beam printer of this embodiment is shown in FIG.
4, a converter 27 for converting Y, M, and C color data having gradation levels into K gradation data, and a laser based on the data generated by the converter 27. A laser beam intensity modulator 28 for modulating the intensity of the beam is provided. The converter 27 is incorporated in the optical unit 10 and the printer control device 11 shown in FIG.

The converter 27 is designed to convert the data in consideration of the weight of each color so as to satisfy the following conversion formula.

K = f (Y, C, M) = 0.2Y + 0.3C + 0.5M (where 0 ≦ Y, M, C, K ≦ 1) Coefficients of Y, C and M 0.2, 0.3 and 0.5 are normalized so that K = 1 at 100% for each color. However, the respective values depend on the characteristics of the output process device, for example, the developer or the photosensitive drum. It is desirable to set the optimum value.

Assuming that Y = 70%, C = 40%, M = 30
%, The output of K is 41%. The size of the output dot is made variable by modulating in the laser beam intensity modulator 28 based on the black gradation level thus generated.

FIG. 15 shows an example of the laser beam intensity modulator 28. The multi-valued data output from the converter 27, here 8-bit (256 level) data, is converted into analog data by the D / A converter 29, and the intensity-modulated laser is output from the laser diode 30. Has become.

The printing process is described in the first embodiment.
The process is similar to.

In this embodiment, the laser beam intensity modulator 28 is used as the modulation means, but the invention is not limited to this, and a pulse width modulator may be used. In this case, the dot size is changed by changing the irradiation time of the laser beam.

[Embodiment 3] A third embodiment of the present invention is shown in FIG.
The following is a description with reference to 6 to 23. still,
The members having the same functions as those in the above-mentioned embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, it is limited to the case where there is no black developer. That is, when there is no black developer when printing black print data, the other three colors of yellow, magenta, and cyan are used for substitute printing.

As shown in FIG. 16, black data having a certain gradation is decomposed into Y, M and C components by a converter 31. In this case, for example, the following weighting is performed for decomposition.

Y = 5K (Y = 1 when Y ≧ 1) C = 3K (C = 1 when C ≧ 1) M = 2K (M = 1 when M ≧ 1) , 0 ≦ Y, M, C, K ≦ 1) Here, regarding the coefficients 5, 3, 2 of K in each color,
Although an appropriate value is set according to the characteristics of the process device, for example, the developer and the photoconductor drum, the above value is used for convenience.

The process up to printing of this embodiment will be described below.
This will be described with reference to FIGS.

First, as shown in FIG. 17, when printing is performed, the print processing device 12 sends a print request signal PAGE to the printer control device 11 (S71). If the print request signal PAGE is 0, it is determined to print, and the yellow process flag YPF, the magenta process flag MPF, the cyan process flag CPF, and the black process flag KPF are set to 1 (S72).

Next, it is judged whether or not the black developer is present (S
73) If there is a black developer, the normal data processing described later is performed (S74), while if there is no black developer, the presence or absence of a yellow developer is determined (S75). If there is no yellow developer, it is necessary to prepare other color developers in order to perform the substitute printing of the black developer, so a message indicating that there is no color developer is displayed to inform the user (S80), Return to start. If there is a yellow developer, it is next determined whether or not the magenta developer is present (S7).
6).

If there is no magenta developer, a message indicating no color developer is displayed to inform the user (S8).
0), return to the start. If you have magenta developer,
The presence / absence of the cyan developer is determined (S77). If there is no cyan developer, a message indicating no color developer is displayed to notify the user (S80), and the process returns to the start. If there is a cyan developer, a black developer-less process described later is performed (S78), and then the printing process is performed (S79).

In the black developer-free process in S78, as shown in FIG. 18, first, the black process flag is set to 0 (S81), then it is displayed that there is no black developer (S82), and printing is continued. It is determined whether or not (S83). If you do not want to continue printing, return to START.If you want to continue printing, use cyan,
Data of each color is created by separating into three colors of magenta and yellow (S84).

The normal data processing in S74 is shown in FIG.
First, the presence or absence of the yellow developer is checked (S91). If there is no yellow developer, the processing without yellow developer is performed (S92), and if there is yellow developer, the presence or absence of magenta developer is checked (S93). If there is no magenta developer, processing without magenta developer is carried out (S94), and if there is magenta developer, the presence or absence of cyan developer is checked (S95). If there is no cyan developer, processing without cyan developer is performed (S96).

In the process without a yellow developer in S92, as shown in FIG. 20, the user is informed that there is no yellow developer (S101), and it is determined whether or not to continue printing (S102). When the printing is not continued, the process returns to the start, and when the printing is continued, the yellow process flag is set to 0 (S103).

In the magenta developer-less process in S94, as shown in FIG. 21, the same process as in the case of yellow (S111 to S113) is performed. The cyan developer-free process in S96 also performs the same process (S121 to S123) as shown in FIG.

Further, in the print process execution process in S79, as shown in FIG. 23, the process flag of each color is checked (S131, S133, S135, S13).
7) If each process flag is 0, the printing process for each color is not executed. On the other hand, if the process flag is not 0, the printing process for each color is executed (S
132, S134, S136, S138). In the case of the present embodiment, instead of the black developer, the other three color developers are used for the substitute printing, so that YPF = 1, MPF = 1, C.
Since PF = 1 and KPF = 0, the printing process of yellow, magenta, and cyan is executed in the printing process shown in FIG. 23, and the black printing process is not executed. The printing process for each color is the same as the process described in the first embodiment.

As described above, when the black developer does not exist, the other three color developers can perform the substitute printing, and therefore, in the monochrome printing of a frequently used document or the like,
The application range of the device is expanded without degrading the function.

[0070]

As described above, in the image forming apparatus according to the first aspect of the present invention, when there is no developer of at least one color among a plurality of colors, there is another print data of the developer which does not exist. The print control unit converts the print data of the developer and prints with another developer.

Therefore, if there is no developer of the desired color,
Substantial printing of other colors can be obtained without stopping the image formation, and the application range of the apparatus is broadened. Further, since the monochrome printing is performed, it is possible to suppress the wasteful consumption of the developer, and at the same time, since the extra process is not performed, the printing time can be significantly shortened. Further, since the print data sent when there is no developer of a desired color is sequentially converted into a single color, there is an effect that the internal storage device can be saved.

As described above, in the image forming apparatus according to the second aspect, the developers of a plurality of colors are yellow, magenta, cyan and black, and at least one of the yellow, magenta and cyan developers is used. When the developer does not exist, it is provided with a print control means for converting the print data of yellow, magenta and cyan into black print data and performing printing using only the black developer by the converted print data. is there.

Therefore, in addition to the effect of the first aspect, since it is possible to perform color halftone (intermediate color) printing by gradation printing of a single black color, black halftone printing corresponding to the color halftone level. The effect is that it becomes possible.

As described above, the image forming apparatus according to a third aspect of the present invention is configured such that printing is represented by a plurality of dots and the dot size of the converted print data is changed according to the print data. Is.

Therefore, in addition to the effect of claim 1,
Higher resolution gradation expression is possible, and gradation reproducibility is improved when a color halftone level is expressed by a single color.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a configuration of a laser beam printer which is a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating an interface between an image processing apparatus and a printer control apparatus.

FIG. 3 is a timing chart of each signal shown in FIG.

FIG. 4 is a block diagram showing a configuration of an image processing apparatus.

FIG. 5 is an explanatory diagram showing a usage example of an internal storage device.

FIGS. 6A to 6D are explanatory diagrams showing conversion examples in the case of yellow. (E)-(h) is an explanatory view showing a conversion example in the case of cyan. (I)-(l) is an explanatory view showing a conversion example in the case of magenta.

7 is an explanatory diagram showing an example in which data of respective colors converted by the example of FIG. 6 are overlapped.

FIG. 8 is a flowchart showing a printing process of the present invention.

9 is a flowchart showing a yellow-free process of FIG.

10 is a flowchart showing a process without magenta in FIG.

11 is a flowchart showing a cyan-free process of FIG.

FIG. 12 is a flowchart showing the black-free processing of FIG.

13 is a flowchart showing a printing process in FIG.

FIG. 14 shows a second embodiment of the present invention,
It is explanatory drawing which shows the example of conversion from yellow, magenta, or cyan to black.

FIG. 15 is a circuit diagram showing a configuration of a laser beam intensity modulator.

FIG. 16 shows a third embodiment of the present invention,
It is explanatory drawing which shows the example of conversion from black to yellow, magenta, or cyan.

FIG. 17 is a flowchart showing a printing process.

FIG. 18 is a flowchart showing a black developer-less process of FIG.

19 is a flowchart showing the normal data processing of FIG.

FIG. 20 is a flow chart showing a process without yellow developer in FIG.

FIG. 21 is a flowchart showing a process without a magenta developer in FIG.

FIG. 22 is a flowchart showing the cyan developer-less process of FIG.

23 is a flowchart showing the printing process of FIG.

[Explanation of symbols]

 11 Printer Control Device 12 Print Processing Device (Print Control Unit) 23 Central Processing Unit 24 Memory 27 Converter 28 Laser Beam Intensity Modulator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03G 15/01 S H04N 1/23 101 C 1/46 H04N 1/46 Z

Claims (3)

[Claims] 1. An image forming apparatus having a plurality of color developing agents, wherein printing is performed by developing with a plurality of color developing agents on the basis of print data for each color. When a color developer does not exist, it is provided with a print control means for converting the print data of the non-existent developer into print data of another existing developer and performing printing with the other developer. Image forming apparatus. 2. The yellow, magenta, cyan, and black developers are yellow, magenta, and cyan, and at least one of the yellow, magenta, and cyan developers does not exist. 2. The image forming apparatus according to claim 1, further comprising a print control unit that converts cyan print data into black print data and performs printing using only the black developer based on the converted print data. . 3. The printing is represented by a plurality of dots, and a conversion means for changing the size of the dots of the converted print data according to the print data is provided.
The image forming apparatus described.