JPH04334454A - Method for driving ink jet printing head - Google Patents

Abstract

PURPOSE:To perform high density printing even when a low density line type ink jet printing head is used by controlling the driving of an ink jet printing head so as to perform printing at the interval 1/N of the dot interval of the line type ink jet printing head. CONSTITUTION:A line type ink jet printing head 1 having a large number of nozzle orifices arranged thereto in a line form at a definite interval is provided. Further, a page memory 3 connected to a CPU 2 controlling printing operation to store the dot data to be printed corresponding to one page and a line register 4 storing the dot data of one line read from the memory 3 are provided. The dot data are read from the dot memory cells of the memory 3 on every N-th cell to perform printing and, at each time when printing is completed, the head 1 is moved by one line with respect to paper. Further, the dot data are read from the dot memory cells on every N-th cell of the memory 3 at every line to perform printing and, after the completion of printing, the head 1 is shifted by 1/N of the interval between nozzle orifices.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving an inkjet printhead that enables high-density printing using a relatively low-density line-type inkjet printhead.

0002

[Prior Art] Conventional inkjet printheads have only been developed as serial type with a small number of dots.
It has been commercialized, but the high-density line type has not been commercialized.

0003

[Problems to be Solved by the Invention] The reason why a high-density line type inkjet print head has not been commercialized is that (1) it is difficult to manufacture because it has multiple nozzles. ■Since there are many nozzles and the ink path becomes narrower, clogging is more likely to occur, making it difficult to ensure reliability. ■Inkjet print heads become expensive. (2) When the density becomes high, when using an electrostrictive element with good energy efficiency, it is difficult to secure enough displacement of the electrostrictive element to obtain a volume change for ejecting ink. etc.

[0004] For this reason, conventional inkjet printheads are only of the serial type, which has the problem of slow printing speed. This invention was made in view of the above-mentioned problems, and an object of the present invention is to provide an inkjet printhead driving method that enables high-density printing even with a relatively low-density line-type inkjet printhead. There is.

[0005]

Means for Solving the Problems and Effects The method for manufacturing an inkjet printhead of the present invention provides a line-type inkjet printhead in which a large number of inkjet discharge nozzle holes are arranged in a line at regular intervals;
A memory is provided that stores at least one page of dot information to be printed in a matrix, and the number of dot storage cells for one row is N times the number of dot holes of the line-type inkjet print head, and the memory stores every N dots from this memory. Dot information is read from the cell and printed using the line-type inkjet print head, and each time one line of printing is completed, the inkjet print head is moved relative to the paper by one line, and each line is read from the memory. Each time, dot information is read from every N dot memory cells,
When printing is completed with the inkjet print head, the inkjet print head is shifted by 1/N of the nozzle hole interval, and N dot storage cells are shifted from the memory by one cell. Dot information is read out from the dot memory cells every other time, and while printing a line, the inkjet print head is moved in this manner by one page relative to the paper while printing the line, and the dot holes of the inkjet print head are printed. A shift of 1/N of the interval is executed N times to print one page of the memory.

[0006] In this inkjet print head driving method, printing is performed at an interval of 1/N of the dot interval of the head, so even if a low density line type inkjet print head of, for example, 2 dots/mm is used. , N=4, it is possible to print at 8 dots/mm.

[0007]

[Examples] The present invention will be explained in more detail with reference to Examples below. FIG. 2 is a perspective view of a line type inkjet print head used in an embodiment of the present invention. In this line type inkjet printhead 1, a plurality of inkjet printheads 11 are arranged in line on one support plate 12, and a circuit board 13 is also mounted on the support plate 12. The circuit board 13 includes a driver IC 14 for driving each electrostrictive element of the inkjet print head 11, respectively. The circuit board 13 includes a driver IC 14 and
Although individual electrodes for driving each inkjet print head 11 are connected by pattern connection and wire bonding, detailed illustration is omitted. Other driver I
The same is true for C14, . . . , 14. Note that 15 is a connector for electrostrictive drive. Note that the driver IC 14 has a built-in shift register, and arbitrarily drives the individual electrodes of each ingjet print head 11, 11. This line type inkjet print head has a relatively low density of about 2 dots/mm.

FIG. 1 is a block diagram showing the circuit configuration of a printer in which the present invention is implemented. This printer includes the above-described inkjet printhead 1 and a CPU that controls the printing operation of this inkjet printhead 1.
2, a page memory 3 that stores dot information to be printed for one page, and 1 read from this page memory 3.
A line register 4 that stores dot information for a line, a motor 5 for paper feeding, a drive circuit 6 that drives the motor 5 for paper feeding in accordance with a command from the CPU 2, and a direction perpendicular to the paper feeding direction for moving the head 1. a motor 7 for the head to shift the head to
A drive circuit 8 for driving the.

As shown in FIG. 4, the page memory 3 has rows x
It has memory cells of 1600×2240 columns and stores one page worth of dot information. Next, the printing operation of the inkjet printer of the above embodiment will be explained with reference to the flowchart shown in FIG. It is assumed that at the start of printing, the leftmost ink nozzle hole 10-1 of the line type inkjet print head 1 is located at point A on the recording paper 9 shown in FIG. When the operation starts, the dot information in the first row of the page memory 3 is read out from the leftmost memory cell in the order of every fourth one. That is, the dot information of cells 1, 5, 9, . . . , 1597 is read out and stored in the row register 4 [step ST (hereinafter abbreviated as ST) 1]. Then, the dot information stored in this row register 4 is input to the inkjet print head 1, and each ink nozzle hole 10-1, 10-2, . . . , 10 of the inkjet print head 1
-400 (see FIG. 4), printing processing for one line is executed all at once (ST2). Then, it is determined whether the print line is the last line of the page memory 3 (ST3), and since this determination is naturally NO at the beginning of printing, the process moves to ST4, and the drive circuit 6
, drives the motor 5 to feed the recording paper 9 by one row (0.125 mm) of the page memory 3, and feeds the recording paper 9 by one row (0.125 mm) of the page memory 3, starting from the leftmost cell in the second row of the page memory 3, every fourth cell, that is, one
, 5, 9, . . . , 1597 are read out and stored in the row register 4 (ST5). and,
This print dot information, that is, the extracted print dot information every fourth on the second line of the page memory 3, is input to the inkjet print head 1, and each ink nozzle 10-
1, . . . , 10-2, . . . , 10-400, the printing process is executed all at once (ST2).

As described above, the processes of ST2 to ST5 are repeated until the last line of print dot information stored in the page memory 3 is read out. When the printing process ends on the last line, the determination in step ST3 becomes YES and the process moves to ST6. At this point, the leftmost ink nozzle 10-1 of the inkjet print head 1 has reached point B in FIG. 1st column, 5th column,
This means that the 7th column, . . . , the 1597th column have been printed.

At ST6, the head motor 8 is activated by the drive circuit 7.
is driven, and the inkjet print head 1 moves to the right by 1/4 of the dot interval (0.125 mm) (ST
6) The leftmost ink nozzle hole 10-1 comes to the position of point C in FIG. Then, in the last row of page memory 3, from the second cell from the leftmost side, every fourth cell, that is, 2, 6, 10
,..., the printed dot information of cells 1598 is read out,
This print dot information is stored in the line register 4, and is input to the inkjet print head 1, where each ink nozzle hole 10-1, 10-2, . . . , 10-400 simultaneously executes the printing process for one line. (ST8). Then, it is determined whether the print line is the first line of the page memory 3 (ST9).
, at first, this judgment is NO, so the process moves to ST10, and the recording paper 9 is reversely fed by one line, that is, 0.125 mm, and the paper 9 is moved backward by one line, that is, 0.125 mm, and the paper 9 is moved one line before the last line of the page memory 3, and is also at the leftmost edge. every fourth from the second, that is, 2,
Print dot information of cells 6, 10, . . . , 1598 is read out and stored in the row register 4 (ST11). Then, this print dot information, that is, the print dot information extracted from every fourth cell in the row before the last row of the page memory 3, is input to the inkjet print head 1.
Each ink nozzle hole 10-1, 10-2,...10-400
The printing process is executed all at once (ST8).

In this way, the processes of ST8 to ST11 are repeated until the first line of the print dot information stored in the page memory 3 is read out. When the printing process is completed up to the first line, the determination in step ST9 is YES.
Then, the process moves to ST12. At this point, the leftmost ink nozzle hole 10-1 of the inkjet print head 1 has reached point D in FIG. This means that every fourth column from the top, that is, the second column, the sixth column, the tenth column, . . . , the 1597th column has been printed. This means that half of the print dot information in the page memory 3 has been printed.

In ST12, the ink jet print head 1 is shifted to the right by 1/4 dot interval, that is, 0.125 mm, and the leftmost ink nozzle hole 10-1 is moved to E in FIG.
Reach the point. Thereafter, although not shown in the flowchart, the printed dot information of every fourth cell from the leftmost end of the page memory 3, that is, cells 3, 7, 11, . . . ~ Repeat the same process as ST5, and set the leftmost ink nozzle hole 10-1 to E.
The third column is printed by moving from point to point F. At this time, the ink nozzles 10-2, . . . , 10-400 print in the 7th column, 11th column, . Then, when the inkjet print head 1 reaches the last row of the recording paper 9, that is, when the position of the leftmost ink nozzle 10-1 reaches point F, the ink print head 1 is further shifted to the right by 1/4 dot interval. .

[0014] This time, from the leftmost end of the page memory 3, every fourth page sequentially, that is, 4, 8, 12, . . . , 160.
Read out the printed dot information of cell 0 and perform the above ST
8 to ST11 are repeated, and the leftmost ink nozzle hole 10-1 is moved from point G to point H to perform printing on the fourth column. At this time, the ink nozzle 10-2
,... 8th column, 12th column,..., 1st column by 10-400
600 columns are printed. Now ink nozzle 10-
1, printing has been performed from point A to point H in FIG.
Since printing for each four columns is completed up to -400, printing for one page is completed.

[0015] With this embodiment printer, for example, A4
Assuming that the size (280 mm) is to be printed, the time required to print one page is 0.5 times the print cycle of the head.
msec, {0.5msec×8 dots/mm}×280(m
m)}×4=4.48 (sec), and printing can be performed in about 5 seconds/sheet.

[0016]

By carrying out the driving method of the present invention, it is possible to use a low-density line-type inkjet print head that is easy to manufacture and inexpensive, even though it prints at high density. Furthermore, by using the line type, it is possible to print at a printing speed of 10 pages or more per minute. Furthermore, by using an energy-efficient electrostrictive element as the drive source of the inkjet print head, a printer that can print at high speed but consumes less power can be constructed, and there are advantages that it can be easily driven by batteries.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of a line type inkjet printer according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a line-type inkjet print head used in the same inkjet printer.

FIG. 3 is a flow diagram for explaining the printing operation of the inkjet printer.

FIG. 4 is an explanatory diagram showing the relationship between the ink nozzle holes of the inkjet print head of the inkjet printer and the page memory.

FIG. 5 is a diagram illustrating a movement locus of an inkjet print head of the same inkjet printer.

[Explanation of symbols]

1 Inkjet print head 2 CPU 3 Page memory

Claims (1)

[Claims] 1. A line-type inkjet print head in which a large number of nozzle holes for ejecting inkjet are arranged in a line at regular intervals, and at least one page or more of dot information to be printed is stored in a matrix, comprising a memory whose dot storage cells are N times the number of dot holes of the line-type inkjet print head, reading dot information from every N dot storage cells from the memory and printing with the line-type inkjet printhead;
Each time one line of printing is completed, the inkjet print head is moved relative to the paper by one line, and dot information is read from the memory from every N dot storage cells for each line, and the After printing with the inkjet print head and printing lines for one page, next move the inkjet print head to 1/1 of the nozzle hole spacing.
By shifting the dot storage cells by one cell from the memory, the dot information is read from every N dot storage cells, and in this manner, the inkjet print head is moved relative to the paper while printing lines. The inkjet print head is characterized by performing line printing while moving by one page, and by shifting the dot hole interval of the inkjet print head by 1/N N times, printing one page of the memory. How to drive an inkjet print head.