KR19990038516A - Printing method of multicolor image forming apparatus - Google Patents

Abstract

If image data of any one color among the image data for each color is received by sequentially receiving image data for each color transmitted from an external device, an independent print command is generated for the image data of any one color for printing. When the print job is completed, the same process is repeated for image data of another color.

Therefore, by storing and printing the image data of one color, and storing and printing the image data of the next color, it is possible to obtain a high quality printed matter by using a memory having a minimum capacity capable of storing the image data of one color.

Description

Printing method of multicolor image forming apparatus

The present invention relates to a printing method of a multicolor image forming apparatus, and more particularly, to a printing method of a multicolor image forming apparatus capable of outputting a high quality printed product with a small size memory.

The present invention also relates to a printing method of a multicolor image forming apparatus that enables printing of high quality printed matter with a smaller size memory.

The present invention also relates to a printing method of a multicolor image forming apparatus that enables to print a high quality printed matter more quickly with a smaller size memory.

In general, a multicolor image forming apparatus using an electrophotographic developing method, for example, a color copier, a color printer, etc., is a photosensitive device having a high pressure while the charging roller rotates. The photosensitive member applied on the outer circumferential surface of is evenly charged.

The charged photosensitive member forms an electrostatic latent image by light rays output from an exposure apparatus (for example, a light source such as a laser diode) that converts a digital signal into laser light.

At this time, the electrostatic latent image formed on the photosensitive device is developed by the toner as it passes through the developing machine to change into a visible image, and the visible image is transferred to the recording paper which is transported and fed by the pickup roller, thereby forming an image on the recording paper. Then, after repeating this process for each color, and the image forming operation is completed for all colors, the image of each color transferred to the recording paper is discharged after it is fixed on the recording paper by the heat and pressure of the fixing apparatus.

When power is supplied to the multi-color image forming apparatus, warm-up is performed for a predetermined time according to the characteristics of the apparatus, and when warm-up is completed, an on-line mode for executing a print command is performed. . When the print command is not received for a predetermined time in the ready mode, the process returns to the standby mode. When the print command is received in the standby mode, the printing is performed through a warm-up process.

At present, the printing method of the multicolor image forming apparatus using the electrophotographic developing method can be roughly divided into two types.

(1) A high quality mode that allows a normal multicolor image forming apparatus to obtain a print of the highest print quality that can be output.

(2) High speed mode that speeds up the printing process even if print quality is somewhat reduced.

At this time, the high quality mode processes the image data to be printed at the highest resolution and printing gradation that the multicolor image forming apparatus can output to maintain the output quality at the highest level. Therefore, when the high quality mode is used, the amount of data to be transmitted from an external device takes a lot of time for image forming work, and as the amount of image data to be transmitted increases, a large capacity memory must be installed. Weighted.

On the other hand, in the high speed mode, the amount of image data received is reduced by using a lower resolution and a smaller gray scale value than the resolution and gray scale value that can be output from the multicolor image forming apparatus. Accordingly, the time required for the image forming operation is shortened, and the amount of image data to be transmitted is small, so that a small amount of memory may be used, so that the user may obtain economic satisfaction. However, such a high speed mode is poor in image quality, and thus it is difficult to apply it in the case of demanding accurate and clear printed matter.

As described above, the high quality mode and the high speed mode are distinguished by the difference in the transmission speed. Since the transmission speed of the transmission line connected between the external device and the multicolor imager is slower than the speed of printing the output of the multicolor imager, the high quality mode is used. In order to satisfy this problem, the capacity of the memory must be increased, and the quality of printed matter cannot be guaranteed in the high speed mode. For example, in the case of a multi-color image forming apparatus having a printing speed of 3 [ppm], in order to process A4 standard image data having a resolution of 300 [dpi] in real time, a transmission speed of image data transmitted from a computer is at least 10 [Mbit]. / sec] or greater. However, the printing speed of the recently commercially available multicolor image forming apparatus is designed to have a performance of 8 [ppm] or 16 [ppm]. Mbit / sec] requires a transmission speed of at least three to six times.

Also, in general, a transmission line for transmitting image data to be transmitted from a computer to a multi-color image forming apparatus is 'RS232C Serial Port', 'IEEE 1284 Parallel Port' or 'Apple Talk Port'. Recently, in order to improve the transmission speed, a LAN cable using a SCSI port or TCP / IP, and a universal serial bus (USB) are also used. However, these transmission lines currently do not provide transmission rates of more than 10 [Mbit / sec].

In addition, since the current transmission line does not provide the desired transmission speed, storage of image data according to the speed difference is an important problem. In general, in a multicolor image forming apparatus, the transmitted image data is compressed using a banding technique or a rendering technique to reduce the occupied amount of the stored memory when storing the image data.

By the way, such a conventional multicolor image forming apparatus produces the following problems.

(1) Since the size of the memory installed in a general multi-color image forming apparatus is about 20 [Mbytes], when a large amount of image data is printed in order to obtain a high quality printed material, there is a fear that a 'Memory Full' may occur. high. Therefore, errors in the printing operation frequently occur.

(2) When a large capacity memory is installed in order to prevent errors in a print job, the price of the multicolor image forming apparatus increases and the price competitiveness falls.

Accordingly, the present invention is to solve the above problems, the first object of the present invention is to sequentially receive the image data created by the external device and to sequentially print by dividing the image data for each color in the order in which the image data is stored in the memory The present invention provides a printing method of a multicolor image forming apparatus that can realize a high quality print mode with a small memory.

In addition, the second object of the present invention is to receive and store the image data of any color of the image data created by the external device, and then perform a print job, the available area of a predetermined size or more occurs in the memory as the print job is performed. The present invention provides a printing method of a multi-color image forming apparatus that can receive and store image data of a different color, thereby realizing a high quality print mode with a smaller memory.

In addition, a third object of the present invention is to receive and store the image data of any color of the image data created by the external device to perform a printing operation, and before the printing operation for the image data of one color is completed another color Multi-color printing enables high quality print mode at high speed with smaller memory size by eliminating the time loss from the transmission of the stored image data until the actual print job is executed by generating the print command for the image data. A printing method of an image forming apparatus is provided.

1 is a schematic block diagram showing the overall structure of a color printer as an example of a multicolor image forming apparatus applied to the present invention.

2 is a schematic structural diagram of a part of a printer engine mounted in a color printer, as an example of the multicolor image forming apparatus applied to the present invention;

3 is a detailed structural diagram of the transfer apparatus shown in FIG.

4 is a flowchart illustrating an operation of the multicolor image forming method according to the first embodiment of the present invention.

5 is an operation waveform diagram of each component according to the operation flowchart of FIG. 4,

6 is an operational flowchart illustrating a process of performing the multicolor image forming method according to the second embodiment of the present invention.

7 is an operation waveform diagram of each component according to the operation flowchart of FIG. 6,

8 is a flowchart illustrating an operation of the multicolor image forming method according to the third embodiment of the present invention.

9 is an operation waveform diagram of each component according to the operation flowchart of FIG. 8.

<Description of the code | symbol about the principal part of drawing>

1: color printer 2: central processing unit

3: rom 4: ram

5: serial / parallel interface unit 6: computer

7: Engine interface section 8: Printer engine

9: image memory 18: photosensitive device

19: charging device 20: exposure device

21: Developer 21a to 21d: Developer

23: transfer device 24: transfer drum

25: transfer barrel 26: dielectric sheet

27: Record Sheet 29: Eliminator

31: adsorption charge roller 32: fixing device

33: hot roller 34: pressing roller

35: developer support

In order to achieve the above objects, the present invention sequentially stores image data for each color continuously transmitted from an external device in an image memory, and image data of any one color among image data for each color is stored in the image memory. If the ratio is over the set value, the print job is started.If the print job for the image data of one color is completed, the print job is stopped.If the ratio of the image data of one color is stored in the image memory, the print job is started. It starts.

In the present invention, the setting value may include a ratio in a state in which image data of any one color is all stored, and image data of any one color from a storage rate in which all of image data of any one color is stored. It may also include a ratio obtained by subtracting a storage rate corresponding to a time interval up to a point at which a print job is performed.

On the other hand, the present invention stores the image data of any one color transmitted from an external device, and if the image data of any one color is stored, the printing operation for the image data of any one color stored, and print job If the progress rate of is greater than or equal to a predetermined value, the transmission job for the image data of one color is started, and when the printing job for the image data of any one color is finished, the printing job is stopped, and all the image data of the other color is stored. When the printing operation for the image data of another color is started.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a printing method of a multicolor image forming apparatus according to the present invention will be described in detail.

FIG. 1 is a schematic block diagram showing the overall structure of a color printer 1 as an example of the multicolor image forming apparatus applied to the present invention.

The central processing unit 2 generally controls the multicolor image forming apparatus according to a predetermined control program stored in a read only memory (ROM) 3, and the random access memory (RAM) 4 performs central processing. It provides a working area of the device (2).

The serial / parallel interface unit 5 is interfaced so that the color printer 1 can communicate with an external device such as a computer 6, and the engine interface unit 7 is provided with image data provided to the printer engine 8. And various types of information generated from the printer engine 8.

The image memory 9 stores image data transmitted from the computer 6, and the video signal generator 10 carries out signal processing of image data to be printed under the control of the central processing unit 2 to internally print the printer engine 8. Supplies an electrical signal to an exposure apparatus (not shown), and the character generator 11 generates a character pattern that matches the character code of the text data transmitted from the computer 6 in the form of a character code. The pattern generator 12 mixes and develops the character pattern generated by the character generator 11 and the image data transmitted from the computer 6 and stored in the image memory 9.

In addition, the color printer 1 includes an operation panel 13 in which a plurality of function keys are arranged so that a user can select various functions of the color printer 1, and an operation signal operated by the user is a panel interface unit ( Interfaced by 14 to the central processing unit 2.

The compander 15 compresses and expands the image data stored in the image memory 9 according to the request of the central processing unit 2, and the data converter 16 stores the image data stored in the image memory 9. Convert to dither processed data or binarized data. The H / V processor 17 then rotates the signal processed image data at a predetermined angle.

Here, the serial / parallel interface unit 5 receives image data from the computer 6 through a parallel interface unit (eg, 'Centronics Interface') or through a serial interface unit (eg, 'RS232C Interface'). . In general, the serial interface and the parallel interface are each independently connected to the computer 6.

2 shows a schematic structural diagram of the printer engine 8 shown in FIG.

As shown in FIG. 2, the printer engine 8 includes a photosensitive device 18 supported by a rotating body (not shown) and coated with a photosensitive member having a thin surface layer on a conductive substrate. Is rotated by a drive (not shown).

A charging device 19 is mounted around the photosensitive device 18 to charge the surface of the photosensitive device 18 to a constant potential. The exposure apparatus 20 is composed of light generating means such as a laser diode to scan the surface of the photosensitive device 18 to form an electrostatic latent image.

The developing apparatus 21 repeatedly forms four color toner images (visual images) sequentially in an electrostatic latent image formed on the surface of the photosensitive apparatus 18 while rotating in contact with the photosensitive apparatus 18 at a uniform pressure. The cleaning device 22 removes the residual toner on the surface of the photosensitive device 18 after the toner image (visual image) forming process is performed.

The transfer device 23 includes a transfer drum supported by the rotating body, and rotates while contacting the photosensitive device 18 at a constant pressure. As shown in FIG. 3, the transfer drum 24 used in the transfer apparatus 23 includes a cylindrical transfer cylinder 25, and a dielectric sheet 26 such as PET or PVDF is formed on the surface of the transfer cylinder 25. ) Is attached.

The transfer material, i.e., recording paper 27, is electrostatically or mechanically adsorbed on the surface of the transfer device 23, and a transfer charging voltage is applied to the transfer barrel 25 of the transfer device 23, so that the photosensitive member of the photosensitive device 18 is applied. The toner image formed on the sheet is transferred to the recording sheet 27. Then, a paper separator 28 is installed on the upper portion of the transfer device 23. When the transfer operation is completed, the tip of the paper separator 28 contacts the surface of the transfer device 23 to transfer the recording paper 27 to the transfer device ( 23). In addition, the static eliminator 29 is installed at an opposite position of the transfer apparatus 23, and the static eliminator 29 discharges the transfer apparatus 23 after the transfer operation is completed.

The cleaning roller 30 is provided at an opposite point of the transfer apparatus 23, and is configured to clean the surface of the transfer apparatus 23 after the transfer operation is completed. An adsorption charge roller 31 is provided at an opposite point from the transfer device 23, and as the adsorption charge voltage is supplied to the adsorption charge roller 31, the recording paper 27 is absorbed and transferred to the transfer device 23. After the transfer operation is finished, when the recording paper 27 separated from the transfer device 23 passes between the heat roller 33 and the pressing roller 34 of the fixing device 32, the toner image transferred to the recording paper 27 The paper is fixed to the recording paper 27 by the heat and pressure of the fixing device 32.

On the other hand, the above-described developing apparatus 21 is a multi-color toner (for example, 'Yellow toner', 'Magenta toner', 'Cyan toner', 'Black' in a rotary turret (Black) toner '), each of which includes four developing devices 21a to 21d, and these four developing devices 21a to 21d each have a cylindrical developer support supported by a rotating body (not shown). It is stored in 35. When the turret of the rotary developing device 21 rotates in a predetermined direction to move the developing devices 21a to 21d to a position facing the surface of the photosensitive device 18, the electrostatic latent image formed on the surface of the photosensitive device 18 is formed. Toners of each color stacked in the developing units 21a to 21d are sequentially applied to form a toner image (visible image) in the photosensitive apparatus 18. Therefore, as the developer support 35 rotates once, the above four colors are developed in sequence, so that images of four colors are formed on the recording paper 27.

Further, below the developing device 21, a toner remaining amount detecting device 36 for detecting the remaining toner amount remaining in each of the developing devices 21a to 21d of the developing device 21 is configured. At this time, the toner remaining amount detecting device 36 receives a light emitting device that scans light at a predetermined angle into the developing object to be measured, and receives light reflected from the light emitting device and reflected by the developing object into an electrical signal corresponding to the amount of light. And a holder for supporting the light emitting element and the light receiving element.

An operation according to the first embodiment of the present invention having such a configuration will be described below with reference to FIGS. 4 and 5.

First, a print job is started by transferring image data to be printed from the computer 6 to the color printer 1 via the serial / parallel interface unit 5. At this time, when a print command is input by the user (S1), the computer 6 separates the image data (Yellow, Magenta, Cyan, Black, etc.) of each color by color. (S2), the separated image data for each color are successively transferred to the color printer 1 (S3) (see Fig. 5A).

Accordingly, the central processing unit 2 of the color printer 1 is configured to display the image data of any one color among the image data of each color input through the serial / parallel interface unit 5, Interpret according to transmission type. Further, the character code data is converted into a matching character pattern through the character generator 11, and synthesized and expanded by combining the converted character pattern and image data for any of the colors interpreted by the central processing unit 2. The synthesized and developed image data is converted into dither processing data or binarized data in accordance with the mode designated by the computer 6 through the data converter 16 or the mode specified through the operation panel 13. The converted image data is compressed by the compensator 15 and sequentially stored in the image memory 9 (S4). Here, the image memory 9 stores all of the image data of one color, prints the image data of one color, and at the same time stores image data of another color continuously transmitted from the computer 6. It should be set to a larger capacity than color image data.

Thereafter, the central processing unit 2 checks whether all the image data of one color is stored in the image memory 9 (S5), and if all the image data of one color is stored in the image memory 9, the central processing unit (2), after transmitting the stored image data of one color to the printer engine (8) (S6), the printing start signal (as shown in Figure 5b) to the printer engine (8) ) Prints the print job (S7). Here, the printing start signal shown in Figure 5b ( ) Indicates the print operation section for each color, and the printing start signal ( Each section of) may be represented by a plurality.

Printing start signal from the central processing unit (2) Is applied at the reference position of the transfer device 23. For each line generated based on the signal (see FIG. 5C) and the BD signal (see FIG. 1) detected from the exposure apparatus 20. A signal (see FIG. 5D) is output to the engine interface unit 7. Central processing unit (2) from the engine interface (7) Signal and In response to the signal, the signal stored in the image memory 9 is extended to the compensator 15 according to the signal, and then output to the video signal generator 10. The video signal generator 10 outputs a VD [7.0] signal (see FIG. 5E), which is video data for driving the exposure apparatus 20.

The process of performing the printing operation thereafter will be described in detail. First, the recording paper 27 fed by the pickup roller of the paper feeding device (not shown) is transferred to the transfer device 23 by the adsorption charging voltage of the adsorption charging roller 31. Is adsorbed on the surface of the dielectric sheet 26 of At this time, the charging device 19 charges the surface of the rotating photosensitive device 18 to a constant potential, and the exposure device 20 such as a laser diode or the like is based on image information of any one color (for example, 'yellow'). When one light is scanned at a predetermined time period, an electrostatic latent image of any one color is formed on the photosensitive member of the photosensitive device 18. At this time, since the plurality of developing units 21a to 21d are sequentially conveyed by the turret of the developing apparatus 21 at the position facing the surface of the photosensitive apparatus 18, the electrostatic latent image formed on the surface of the photosensitive apparatus 18 is developed. It is developed and visualized by the toner layer (any one of 21a to 21d).

The toner image visualized by the developing apparatuses 21a to 21d is rotated to a position opposite to the transfer drum 24 of the transfer apparatus 23, i.e., to the developing position, with the rotation of the photosensitive device 18. FIG. The toner image rotated to the position opposite to the transfer drum 24 is transferred to the recording paper 27 adsorbed to the dielectric sheet 26 of the transfer drum 24 by the transfer voltage applied to the cylindrical transfer cylinder 25. .

On the other hand, the toner remaining on the surface of the photosensitive device 18 is removed by the cleaning device 22, and the photosensitive device 18 finishes the printing job of one color, and switches to the ready state for printing the next color image data. do.

Thereafter, the central processing unit 2 checks whether the printing operation for the image data of one color is completed (S8), and stops the printing operation if the printing operation for the image data of one color is completed (S9). It is checked whether a print job for image data of all colors is completed (S10). If the printing operation for the image data of all colors is not completed in step 10 (S10), the process returns to step 5 (S5) above and repeats all the processes after step 5 (S5).

That is, in the case of printing the image data of the next color, when the image data of the next color is completed to be stored in the image memory 9, the central processing unit 2 sends a printing start signal to the printer engine 8 ( ), And the same signal flow as the printing process of one color described above occurs.

Accordingly, when the electrostatic latent image of any other color (for example, 'magenta') is formed on the surface of the photosensitive device 18, the turret of the developing device 21 rotates to move the next developing device 21a to 21d. It is conveyed to the position which opposes the surface of the photosensitive device 18. Accordingly, the electrostatic latent image formed on the surface of the photosensitive device 18 is visible by a toner layer of any other color, that is, a magenta toner layer, formed in the developing units 21a to 21d by the above-described process. The toner image of any other color is transferred again to the surface of the recording paper 27 on which the toner image of any one color has already been transferred by the transfer voltage of the transfer barrel 25.

This process applies equally to any other color (eg 'cyan' and 'black').

When the toner images of all colors are transferred to the surface of the recording sheet 27 in this manner, the paper separator 28 contacts the surface of the transfer apparatus 23 to separate the recording sheet 27 from the transfer apparatus 23.

The respective toner images for the above four colors are transferred, and the image of the recording paper 27 separated from the transfer apparatus 23 by the paper separator 28 is generated in the heat roller 33 of the fixing apparatus 32. The printing process is completed by being fixed to the recording sheet 27 by a predetermined temperature and the pressing force of the pressing roller 34 and discharged to the recording sheet discharge port (not shown).

On the other hand, if it is determined in step 10 (S10) that the print job is completed for the image data of all colors, the print job is terminated.

That is, the essential point of the first embodiment is to continuously transmit image data of each color from the computer 6 to the printer engine 8 in order to print the image data, and the image data of the first color is all transferred to the image. When stored in the memory 9, the printer engine 8 performs a print job on the image data of the first color. Subsequently, when the printing operation for the image data of the first color is completed, the apparatus waits until all of the image data of the second color is stored in the image memory 9, and then the image data of the second color is all stored in the image memory 9. When stored, the printing operation is performed on the image data of the second color, and this process is repeated for each color until the printing operation on the image data of all the colors is completed.

Therefore, a high quality printed matter can be obtained using a small memory.

Meanwhile, the operation according to the second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

As described above with reference to FIG. 4, the print job is started by transferring the image data to be printed from the computer 6 to the color printer 1 via the serial / parallel interface unit 5. At this time, when a print command is input by the user (S11), the computer 6 separates the image data (Yellow, Magenta, Cyan, Black, etc.) of each color by color. (S12), and transfers the image data of any color among the separated image data for each color to the color printer 1 (S13) (see Fig. 7A).

Accordingly, the central processing unit 2 of the color printer 1 is configured to display the image data of any one color among the image data of each color input through the serial / parallel interface unit 5, Interpret according to transmission type. Further, the character code data is converted into a matching character pattern through the character generator 11, and synthesized and expanded by combining the converted character pattern and image data for any of the colors interpreted by the central processing unit 2. The synthesized and developed image data is converted into dither processing data or binarized data in accordance with the mode designated by the computer 6 through the data converter 16 or the mode specified through the operation panel 13. The converted image data is compressed by the compensator 15 and stored in the image memory 9 (S14). Here, the image memory 9 may be set to the same capacity as the image data of one color so that only image data of one color can be stored.

Thereafter, the central processing unit 2 checks whether all the image data of one color is stored in the image memory 9 (S15), and when all the image data of one color is stored in the image memory 9, the central processing unit (2) outputs a control signal to the computer 6 to suspend the transmission operation of the image data (S16), transfer the stored image data of one color to the printer engine 8 (S17), and then print the printer engine ( 8, a printing start signal (as shown in FIG. 7B) And prints the print job (S18).

Printing start signal from the central processing unit (2) Is applied at the reference position of the transfer device 23. For each line generated based on the signal (see FIG. 7C) and the BD signal (see FIG. 1) detected from the exposure apparatus 20. A signal (see FIG. 7D) is output to the engine interface unit 7. Central processing unit (2) from the engine interface (7) Signal and In response to the signal, the signal stored in the image memory 9 is extended to the compensator 15 according to the signal, and then output to the video signal generator 10. The video signal generator 10 outputs a VD [7.0] signal (see FIG. 7E), which is video data for driving the exposure apparatus 20.

The subsequent process of performing the print job is the same as the operation in FIG.

On the other hand, the central processing unit 2 checks whether the usable area of the image memory 9 is equal to or larger than a predetermined value before the printing operation for image data of one color is finished (S19), and the image memory 9 If it is determined that the usable area of the &lt; RTI ID = 0.0 &gt;) is more than a predetermined value, &lt; / RTI &gt; Here, if there is image data of another color waiting to be transmitted, this means that the transmission operation for the image data of all colors is not finished, so that the CPU 2 outputs a control signal to the computer 6 for transmission. A request is made to transmit image data of another color that is waiting, and accordingly, the computer 6 transmits image data of another color that is waiting to be transmitted to the color printer 1 (S21).

If it is determined in step 20 (S20) above that there is no image data of one color waiting to be transmitted from the computer 6, this means that the transmission operation for the image data of all colors has been completed. Instead of performing step 21 (S21), the process proceeds directly to step 22 (S22), which will be described later.

Thereafter, the central processing unit 2 checks whether the printing operation for the image data of one color is completed (S22), and stops the printing operation if the printing operation for the image data of one color is completed (S23). It is checked whether or not the printing operation for the image data of all colors is completed (S24). If the printing operation for the image data of all colors is not completed in this step 24 (S24), the process returns to the above step 15 (S15) and repeats all the processes after the step 15 (S15).

On the other hand, if it is determined in step 24 (S24) that the print job is completed for the image data of all colors, the print job is terminated.

That is, the essential point of the second embodiment is to transfer the image data of any color of the image data of each color from the computer 6 to the printer engine 8 in order to print the image data, and the image data of the first color. Are all transferred and stored in the image memory 9, the central processing unit 2 requests the computer 6 to stop the image data transfer operation, and then the printer engine 8 prints the image data of the first color. Do this. At this time, as a print job is performed on the image data of the first color, an available area is generated in the image memory 9, and when the available area is larger than or equal to a predetermined size, the image data of the second color is transmitted. Ask the computer 6. Subsequently, when the printing operation for the image data of the first color is completed, the apparatus waits until all of the image data of the second color is stored in the image memory 9, and then the image data of the second color is all stored in the image memory 9. When stored, the printing operation is performed on the image data of the second color, and this process is repeated for each color until the printing operation on the image data of all the colors is completed.

Therefore, high quality printed matter can be obtained using a smaller memory capacity.

Meanwhile, the operation according to the third embodiment of the present invention will be described with reference to FIGS. 8 and 9.

As described above with reference to FIGS. 4 and 6, the print job is started by transferring the image data to be printed from the computer 6 to the color printer 1 via the serial / parallel interface unit 5. At this time, if a print command is input by the user (S25), the computer 6 separates the image data (Yellow, Magenta, Cyan, Black, etc.) of each color by color. (S26), the separated image data for each color are successively transmitted to the color printer 1 (S27) (see Fig. 9A).

Accordingly, the central processing unit 2 of the color printer 1 is configured to display the image data of any one color among the image data of each color input through the serial / parallel interface unit 5, Interpret according to transmission type. Further, the character code data is converted into a matching character pattern through the character generator 11, and synthesized and expanded by combining the converted character pattern and image data for any of the colors interpreted by the central processing unit 2. The synthesized and developed image data is converted into dither processing data or binarized data in accordance with the mode designated by the computer 6 through the data converter 16 or the mode specified through the operation panel 13. The converted image data is compressed by the compensator 15 and continuously stored in the image memory 9 (S28). Here, the image memory 9 can be set to a smaller capacity than image data of one color.

Thereafter, the central processing unit 2 checks whether the storage rate of one color of image data stored in the image memory 9 is equal to or greater than the preset value (S29), and the preset storage value of one color of image data is set. If abnormal, the stored image data of one color is transmitted to the printer engine 8 (S30), and then the printing start signal (shown in FIG. 9B) to the printer engine 8 ( And prints the print job (S31). Here, since the image data of one color stored in the image memory 9 is transmitted from the printer engine 8, it takes a predetermined time until the actual print job is performed, so that the image data of one color is transferred to the printer engine 8 The printing start signal from the time point at which the image data is stored as much as the time interval between the time point at which the actual print job is performed. ).

Printing start signal from the central processing unit (2) Is applied at the reference position of the transfer device 23. Of each line generated based on the signal (see FIG. 9C) and the BD signal (see FIG. 1) detected from the exposure apparatus 20. A signal (see FIG. 9D) is output to the engine interface unit 7. Central processing unit (2) from the engine interface (7) Signal and In response to the signal, the signal stored in the image memory 9 is extended to the compensator 15 according to the signal, and then output to the video signal generator 10. The video signal generator 10 outputs a VD [7.0] signal (see FIG. 9E) which is video data for driving the exposure apparatus 20.

The subsequent process of performing the print job is the same as the operation in Figures 4 and 6 mentioned above.

On the other hand, the central processing unit (2) checks whether the printing operation for the image data of one color is finished (S32), and if the printing operation for the image data of the corresponding color is completed (S33) after pausing the printing operation (S33). In step S34, it is checked whether printing of all color image data is completed. Here, if it is determined that the printing operation for the image data of all colors is not completed, the central processing unit 2 returns to the aforementioned step 29 (S29) and repeats all the processes after the step 29 (S29), If it is determined in step 34 (S34) that the print job for all the color image data has been completed, the print job is terminated.

That is, the essential point of the third embodiment is a point in time at which image data of each color is continuously transmitted from the computer 6 to the printer engine 8 in order to print the image data, and all of the image data of the first color is transferred. A printing start signal at a time point earlier than a predetermined time from (when the storage rate at which the image data is stored in the image memory 9 is equal to or larger than a preset value). Is to start a print job.

Therefore, high quality printed matter can be obtained more quickly by using a smaller memory capacity.

As a result, according to the printing method of the multicolor image forming apparatus according to the present invention, the following advantages occur.

(1) High-quality printed matter using a small-capacity image memory capable of storing image data of one color by receiving image data of all colors continuously and performing a print job when all image data of one color is stored. Can be obtained.

(2) After all the image data of one color is stored and the printing operation is performed, if the usable area of the image memory is greater than or equal to the predetermined value, the image data of the other color even during printing of the image data of one color is performed. By receiving the, high quality printed matter can be obtained using a smaller capacity image memory.

(3) If image data of all colors is continuously transmitted and before all the image data of one color is stored, that is, if the storage rate of the image data stored in the image memory is equal to or greater than a preset value, a print job of the corresponding color is performed. Thus, a high quality printed matter can be obtained more quickly by using a smaller capacity image memory.

(4) Printing errors due to 'memory pool' can be prevented by sequentially processing the multicolor image data for each color using a 20 [Mbyte] size memory mounted in a conventional multicolor image forming apparatus.

(5) By outputting high-quality printed matter using a small memory, it is possible to manufacture and supply a low-cost multicolor image forming apparatus, thereby improving the price competitiveness.

Claims (8)

A printing method of a multicolor image forming apparatus for receiving multicolor image data from an external device and printing the multicolor image data: Dividing the multi-color image data for each color by the external device and continuously transmitting the image data for each color; Sequentially storing the image data for each color; The image data of any one color stored is waited until the ratio in which the image data of any one color among the image data for each color is stored is greater than or equal to a set value, and the image data of any one color is more than the set value. Performing a printing operation on the; Stopping a print mode when a print job for the image data of any one color is completed; And repeating the interruption step from the transmission step until all the print jobs for the image data for each color are finished. The method of claim 1, wherein the multi-color image data, A printing method of a multicolor image forming apparatus including yellow, magenta, cyan, and black. The method of claim 1, wherein in the printing step, The printing operation is performed by generating one printing start signal with respect to the image data of one color and the other printing starting signal is generated with respect to the image data of one color to perform the printing operation. A method of printing a multicolor image forming apparatus in which a signal is repeatedly generated for each color. The method of claim 1, wherein the set value, And a ratio in a state where all of the image data of any one color is stored. The method of claim 1, wherein the set value, A multi-color including a ratio obtained by subtracting a storage rate corresponding to a time interval from a storage rate in which the image data of any one color is all stored to a time point at which a print job for the image data of any one color is performed; A printing method of an image forming apparatus. A printing method of a multicolor image forming apparatus for receiving multicolor image data from an external device and printing the multicolor image data: Dividing the multi-color image data by each color in the external device and transmitting image data of any one color among the image data for each color; Storing image data of any one color; Waiting until all of the image data of any one color is stored and performing a printing operation on the image data of any one color stored when all of the image data of any one color are stored; Stopping a print mode when a print job for the image data of any one color is completed; And repeating the interruption step from the transmission step until all the print jobs for the image data for each color are finished. The method of claim 6, wherein the multi-color image data, A printing method of a multicolor image forming apparatus including yellow, magenta, cyan, and black. The method of claim 7, wherein in the printing step, The printing operation is performed by generating one printing start signal with respect to the image data of one color and the other printing starting signal is generated with respect to the image data of one color to perform the printing operation. A method of printing a multicolor image forming apparatus in which a signal is repeatedly generated for each color.