JP2000033717A - Color printer and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To handle this printer as a regular printer and to dispense with an exclusive printer driver. SOLUTION: Image data received from a standard printer driver is transmitted to a print head via a raster buffer 15 having a first developing area 17 and a save area 18. The image data is shifted to the save area 18 so as to cancel an offset of nozzle groups in the print head 9. The image data read out to the first developing area 17 is moved to the save area 18, then the developing area 17 can be used by the next reading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a color printer for printing a color image by an ink jet print head and a control method thereof.

[0002]

2. Description of the Related Art In an ink jet printer, printing is performed so that a plurality of printing dots are arranged in a line on a printing paper. For example, in an ink jet serial printer for color printing, a print head in which nozzle groups for printing dots of each color of cyan, magenta, yellow, and black are arranged vertically and horizontally is used. When an image signal of each color component is supplied to the print head and the print head is moved at a constant speed in the sub-scanning direction, a color image is printed on paper. The color image signal is converted into image data for each color component by a printer driver in advance, and is supplied to the print head of each color.

[0003]

However, the above-mentioned prior art has the following problems to be solved. Of the nozzle groups for each color component that make up the print head,
There is a print head having a structure in which a nozzle group for black printing is offset by one raster when viewed in the main scanning direction from other nozzle groups. When this print head is used, the image data generated on the printer driver side needs to be processed in consideration of the offset amount of the data for black printing. However, this requires the design of a printer driver dedicated to the printer, and is not versatile. Another problem is that a printer driver that is provided as a standard feature in an operating system (OS) of a personal computer cannot be used.

[0004]

The present invention employs the following structure to solve the above problems. <Structure 1> A print head having a structure in which a nozzle group of some color components is offset in the sub-scanning direction from a nozzle group of another color component among a plurality of color component nozzle groups, A raster buffer for temporarily holding the image data transferred to the print head; and a control unit for controlling the transfer of image data from the raster buffer to the print head. A first development area for holding the image data to be supplied to the nozzle groups of the color components in raster units and a second development area for holding the image data to be supplied to the nozzle groups of the other color components in raster units are provided. A save area for storing image data of the number of rasters corresponding to the offset is added to the first development area. The operation of sequentially reading the image data of the number of rasters that the nozzle group of the color component can print in one pass from the second development area is repeated to supply the image data to the nozzle group of another color component. After reading the image data of the number of rasters that the nozzle group of some color components can print in one pass from the save area and the first development area, the offset left unread in the first development area Is transferred to the save area, and again,
The image data of the number of rasters at which the nozzle groups of some of the color components can be printed in one pass is stored in the save area and the first area.
Repeat the operation of reading from the development area of
A color printer that controls the supply of the image data to the nozzle groups of the partial color components.

<Structure 2> For a print head having a structure in which some of the nozzle groups of the color components are offset in the sub-scanning direction from the nozzle groups of the other color components among the plurality of color component nozzle groups. When supplying the image data, the image data transferred from the printer driver to the print head is temporarily held in a raster buffer, and the image data is read out from the raster buffer for the nozzle groups of some of the color components. And controlling the readout range so as to cancel the offset amount.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The printer of the present invention transfers image data received from a standard printer driver to a print head via a raster buffer so that the image data from the raster buffer is offset so as to cancel the nozzle group offset. Controls data reading. Therefore, the printer can be handled in the same manner as a general printer, and does not require a dedicated printer driver.

Hereinafter, embodiments of the present invention will be described with reference to specific examples. <Specific Example> FIG. 1 is a block diagram showing a specific example of the color printer of the present invention. A receiving circuit 2 is connected to a cable 1 connected to a higher-level device (not shown), and the print data received here is configured to be input to a control unit 3. The control unit 3 includes an I / O control circuit 4, a CGROM (character generator read only memory) 5, a ROM (read only memory) 6, an RA
M (random access memory) 7 is connected.

A print head 9 is connected to the I / O control circuit 4 via a print head control circuit 8. Further, a space motor 11 is connected via a space motor control circuit 10, and a line feed motor 13 is connected via a line feed motor control circuit 12. The overall hardware configuration is no different from a conventional printer. RAM
7, a storage area corresponding to the raster buffer 15 and the column buffer 16 is set. The print head 9 includes a plurality of color component nozzle groups.

FIG. 2 is a structural explanatory view of the print head. As shown, the print head has a cyan nozzle group 2
1, a magenta nozzle group 22, a yellow nozzle group 23, and black nozzle groups 24 and 25 are provided. Each nozzle group includes nozzles 20 arranged in a line at equal intervals in the sub-scanning direction as shown in the drawing. The interval between the nozzles 20 is 1/150 inch as shown in the figure. Although the number of nozzles in each nozzle group is four in this figure, an actual head described later has 56 nozzles per color. Of these nozzle groups,
Some of the color components, that is, the black nozzle group 24 here is offset by one raster in the sub-scanning direction from the nozzle groups of the other color components.

When the head scans for one pass in the main scanning direction and performs printing, it moves by 1/300 inch in the sub-scanning direction and performs printing for the next one pass again. Therefore, the density of the printed dots is 1/300 in the sub-scanning direction.
It becomes an inch interval. The offset amount of the nozzle group 24 is 30
It is 1/0 inch, which is called one raster. A pair of nozzle groups 24 and 25 are provided for printing black,
The two are arranged so as to be shifted from each other by one raster in order to speed up the printing operation in black printing. That is, at the time of black printing, odd-numbered raster data is supplied to the nozzle group 24, and even-numbered raster data is supplied to the nozzle group 25, and data for eight rasters is printed at one time in one pass.

On the other hand, in the case of color printing, the nozzle group 2
1, 22, 23 and 24 are used. The operation and problems when color printing is performed using these nozzle groups will be described below.

FIG. 3 is an explanatory diagram of the printing position shift operation. The figure shows a comparison between a case where the character “I (English character eye)” is printed in cyan and a case where it is printed in black. Each of white circles, black circles, and gray circles represents one dot printed by one nozzle. Assuming that the cyan data is received by the printer and stored in the raster buffer, the state is as shown in the upper left of FIG. Gray circle dots correspond to cyan dots to be printed. White circle dots are not printed. Each raster has C1,
C2, C3, C4 and C5 are displayed. In the data on the right side, black circles are black dots. For black data,
B1, B2, B3, B4, and B5 are displayed on each raster. The raster spacing is 1/300 inch.

As shown in FIG. 2, when printing is performed by nozzle groups having a nozzle interval of 1/150 inch as viewed in the sub-scanning direction, first, odd-numbered raster data is transferred to these nozzle groups. The first scan is performed by scanning the print head in the main scanning direction. C of the cyan data shown in FIG.
Rasters 1, 1 and 3 are printed in the first pass.
Thereafter, the print head is shifted by 1/300 inch in the sub-scanning direction, and printing is performed on even-numbered rasters C2 and C4. By such an operation, a print result as shown in the lower left of FIG. 3 is obtained. The same applies to printing of black data.

However, if the black nozzle group 24 is offset by one raster in the sub-scanning direction, as shown in FIG. And printing is performed, the printing result is as shown in the lower part of FIG. The characters "I" of cyan and black, which should be printed at the same position on the left and right, are printed shifted from each other by one raster in the sub-scanning direction. When a standard printer driver is used, image data having such contents is received through the receiving circuit 2 shown in FIG. To handle this on the printer side and eliminate the effects of offset,
The printer of the present invention has the following structure.

Returning again to FIG. 1, the raster buffer 15
Temporarily holds image data transferred from the printer driver of the host device (not shown) to the print head 9. The control unit 3 controls the transfer of image data from the raster buffer 7 to the print head 9. The raster buffer 15 stores the first development area 1 described later with reference to FIG.
7 and a second development area 19. The first development area 17 holds image data to be supplied to the black nozzle group in raster units.

The second development area 19 holds image data to be supplied to nozzle groups of color components other than black in raster units. Further, a save area 18 for storing image data for one raster corresponding to the offset is added to the first development area.

FIG. 4A is a diagram illustrating the configuration of a raster buffer. As shown in FIG.
Has a first development area 17, a save area 18, and a second development area 19. Assuming that the nozzle group of each color is composed of, for example, 56 nozzles, both the first development area 17 and the second development area 19 are set so that 224 raster image data can be stored. Therefore, in each case, two rows of image data can be stored in two passes.

The second development area 19 is provided for each of cyan C, magenta M, and yellow Y. The second development area 19 is used as usual.
On the other hand, as shown in FIG.
A save area 18 for the raster is added.

FIG. 2B is an explanatory diagram of a raster buffer format. Generally, image data is serially input in the main scanning direction. This is expanded in raster units one byte at a time,
Are stored in the raster buffer in the order of 1 byte, 2 bytes, 3 bytes, and so on. On the other hand, as shown in FIG.
In this example, 56 nozzles of image data are supplied to the nozzle group of the print head in the sub-scanning direction. Therefore, the image data developed in the raster buffer is cut out in the sub-scanning direction and transferred. Such a process is called raster column conversion, and as shown in FIG.
Data is transferred one byte at a time in the order of 2 bytes, 3 bytes. The data transfer control from the raster buffer to the column buffer is the same as the conventional technique, and a detailed description is omitted.

FIG. 5 is an explanatory diagram for explaining the operation principle of the present invention. FIG. 7A is a diagram illustrating a specific image data transfer operation. (B) is an explanatory view of the operation principle. The control unit 3 shown in FIG. 1 executes an image data transfer operation as shown in FIG. First, the input print image data is held in the first development area 17. Next, the control unit 3 reads image data of the number of rasters that can be printed by the nozzle group of the black color component in one pass from the save area 18 and the first development area 17. next,
The raster image data corresponding to the offset left unread in the first development area 17 is transferred to the save area 18.

For example, if image data for 224 rasters is held in the first development area, the save area 1
The image data of 56 rasters is converted into a raster column by combining image data of one raster No. 8 and 55 rasters corresponding to the even-numbered rasters in the first development area, and is transferred to the column buffer. At first, it is assumed that the save area 18 holds data of one blank raster. Thereafter, this data is transferred to the black nozzle group.

When the image data of the even-numbered raster is transferred, the image data of the odd-numbered 56 rasters is read from the first development area 17 next. As a result, data of 111 rasters out of data of 112 rasters in the first development area is read. Therefore, the image data of the 112th raster for 113 rasters is left unread.

Next, reading of the remaining 112 rasters of image data newly held in the first development area 17 is started. At this time, image data for 56 rasters corresponding to the even-numbered rasters is read from the data of the 112th raster left unread, and transferred to the black nozzles. Further, the image data for 56 rasters among the image data for the remaining 57 rasters is transferred to the black nozzle group for odd-numbered rasters. Then, the last remaining image data for one raster is transferred to the save area 18 again and held therein, and new image data for 224 rasters is received.

By repeating such operations, reading from the raster buffer is controlled. The control for reading image data from the second development area 19 shown in FIG. 4 is exactly the same as the procedure described with reference to FIG.

Even if the area of the development area is widened, the same operation as described above is performed. When the development area is large, only the intermediate repetition processing is different. The same part is used for first using the data in the save area and transferring the last raster data to the save area for the next processing. Hereinafter, a specific operation example will be described. (1) When there is an area for 224 rasters in the development area, the data of the save area 18 and the development area even-numbered (2
(Raster to 110 raster) data is converted into a raster column. The odd-numbered data (1st raster to 111 rasters) of the development area is subjected to raster column conversion. Raster column conversion is performed on the even-numbered data (112 to 222) of the development area. The odd-numbered data (113 to 223) of the development area is subjected to raster column conversion. Save area 1 in the raster area 224 raster data
Transfer to 8.

(2) When there is an area for 336 rasters in the development area The data of the save area 18 and the even-numbered (2
(Raster to 110 raster) data is converted into a raster column. The odd-numbered data (1st raster to 111 rasters) of the development area is subjected to raster column conversion. Raster column conversion is performed on the even-numbered data (112 to 222) of the development area. The odd-numbered data (113 to 223) of the development area is subjected to raster column conversion. Raster column conversion is performed on the even-numbered data (224 to 334) of the development area. The odd-numbered (225 to 335) data in the development area is subjected to raster column conversion. Save area 336 raster data to save area 1
Transfer to 8.

Next, the operation principle of the above control will be described with reference to FIG. As shown in this figure, image data for L rasters are transferred from the host device to the raster buffer 15 for printing, for example, one line of characters.
When this is supplied to the black nozzle group as it is and printing is performed,
The printing position shift as described with reference to FIG. 3 occurs. Therefore, as shown in FIG. 5B, using the save area 18, image data for the offset L rasters is extracted as an output. Thereafter, the offset is kept as it is, and printing is performed to the end. As a result, the printed data is shifted in the sub-scanning direction by one raster.

If the save area 18 is not provided, the same read control as in the prior art is performed. Read control from the first development area does not become complicated control simply by shifting by one raster or several rasters.
Moreover, this allows the image just printed to be shifted in the sub-scanning direction by the width of the save area 18, thereby offsetting the offset.

FIG. 6 is a flowchart showing the overall operation of the above-described color printer. First, step S
In 1, the image data transferred from the printer driver of the host device is developed in the first development area 17 and the second development area 19 of the raster buffer 15. next,
In step S2, a raster column conversion process is performed for black and other colors under different controls.

Next, in step S3, the column buffer data is printed. Thus, printing of one line, in the above example, two passes is completed. Next, step S
In step 4, the data of the last raster line left unread in the first development area is moved to the save area 18. Then, in step S5, it is determined whether printing of one page has been completed. If not completed, the operations of steps S1 to S4 are repeated.

When printing of one page is completed, the process proceeds to step S6, and it is determined whether or not all save area data is invalid. That is, it is determined whether or not all printing has been completed. If valid data remains, this requires printing, so the process proceeds to step S7 for only one raster worth of data in the save area to perform raster column conversion processing. Then, the flow advances to step S8 to print the column buffer data. Finally, in step S9, the printing paper is discharged and printing is completed.

Note that the offset amount and the offset direction of some of the nozzle groups as described above are arbitrary, and the nozzle groups that are offset need not necessarily be those for black.
That is, the nozzle groups of two or more colors may be offset.

[0033]

As described above, when a print head having a structure in which the nozzle groups of some color components are offset is used, a save area capable of holding image data corresponding to the offset amount is provided in the buffer memory. By controlling the readout of image data from the save area and the raster buffer so as to offset the offset amount, the corresponding nozzle group can be printed using a versatile printer driver. Become. As a result, the special processing load on the printer driver side is reduced, so that the print control becomes more efficient and the printing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a color printer of the present invention.

FIG. 2 is a diagram illustrating the structure of a print head.

FIG. 3 is an explanatory diagram of a printing position shift operation.

FIG. 4A is a diagram illustrating the configuration of a raster buffer, and FIG.
FIG. 3 is an explanatory diagram of a raster buffer data format, and FIG. 3C is an explanatory diagram of a column buffer data format.

5A is an explanatory diagram of a transfer operation, and FIG. 5B is an explanatory diagram of an operation principle.

FIG. 6 is an operation flowchart of the color printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable 2 Receiving circuit 3 Control part 4 I / O control circuit 5 CGROM 6 ROM 7 RAM 15 Raster buffer 16 Column buffer 17 First development area 18 Save area 19 Second development area

Claims (2)

[Claims] 1. A print head having a configuration in which a nozzle group of a part of color components among nozzle groups of a plurality of color components is offset in a sub-scanning direction from a nozzle group of another color component. A raster buffer for temporarily holding image data transferred from the raster buffer to the print head; and a control unit for controlling the transfer of image data from the raster buffer to the print head. A first development area that holds image data supplied to the nozzle group of the color component in a raster unit and a second development area that holds image data supplied to the nozzle group of the other color component in a raster unit. Provided, the first
In the development area, a save area for storing image data of the number of rasters corresponding to the offset is added, and the control unit converts the image data of the number of rasters that the nozzle group of the other color component can print in one pass. The operation of sequentially reading out from the second development area is repeated to supply the image data to the nozzle groups of other color components, and the number of raster images that the nozzle groups of some color components can print in one pass. Data is stored in the save area and the first
After the image data is read from the development area, the image data of the number of rasters corresponding to the offset left unread in the first development area is transferred to the save area, and the nozzles of the partial color components are again transferred. The operation of reading out image data of the number of rasters that can be printed by the group in one pass from the save area and the first development area is repeated to supply the image data to the nozzle groups of the partial color components. A color printer characterized by controlling. 2. A print head having a configuration in which a nozzle group of a part of color components among nozzle groups of a plurality of color components is offset in a sub-scanning direction from a nozzle group of another color component.
When supplying image data, temporarily storing the image data transferred from the printer driver to the print head in a raster buffer, and reading out the image data from the raster buffer for the nozzle groups of some of the color components And controlling the readout range so as to cancel the offset amount.