JP2003182079A - Ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an inexpensive ink jet printer having a nozzle array arranged obliquely by suppressing increase of print data control circuits even if the number of nozzles is increased. <P>SOLUTION: In the ink jet printer comprising a head having an array of a plurality of nozzles for ejecting ink drops, piezoelectric elements for ejecting ink from the nozzles, and a circuit for driving the piezoelectric elements selectively wherein the nozzle array is arranged obliquely and printing is performed by ejecting ink from the nozzles toward a sheet, a print data control circuit for shifting print data transferred from a host unit to the nozzle array arranged obliquely is a combination of a shift register having a width of a plurality of bits constituted of an RAM, and a shift register constituted of a logical circuit having a different length for each nozzle. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus having a head having a plurality of nozzles for ejecting ink droplets and ejecting ink from the nozzles for printing.

[0002]

2. Description of the Related Art FIG. 5 shows a nozzle arrangement of an ink jet printing apparatus. 12 nozzles at √5 / 300 inch intervals
Eight nozzles are arranged on a straight line. The nozzle rows are attached at an angle of 1/300 inch in the horizontal direction and 2/300 inch in the vertical direction with respect to the paper transport direction. Ink is ejected from the nozzle every time the paper moves 1/300 inch, and printing is performed with a dot density of 300 dpi in both the vertical and horizontal directions.

FIG. 3 shows a print data control circuit of a conventional ink jet printing apparatus. A print data control circuit of a conventional inkjet printing apparatus uses a logic circuit to configure a shift register 240 having a 1-bit width for each nozzle with respect to a nozzle array arranged obliquely with respect to a sheet conveyance direction. The number of shifts of 240 is adjusted to the number of dots according to the distance in the vertical direction from the first nozzle of the nozzle row to that nozzle. In the initial state, the shift register 240 is cleared to "0" so as not to perform extra printing.

Print data is transferred line by line from the upper layer device 100 in the horizontal direction. This print data is stored in the shift register 2 corresponding to each nozzle of the print data control circuit.
40 is input. At this time, the data in the shift register 240 is shifted by 1, and the output data is latched in the piezoelectric element drive circuit 150. Piezoelectric element drive circuit 150
Is the piezoelectric element 1 when the latched data is "1".
60 is driven and ink is ejected from the corresponding nozzle,
When it is "0", the piezoelectric element 160 is not driven, so that no ink is ejected. When the printing of one dot line is completed, the paper not shown is moved by 1/300 inch and the above is repeated. In this way, by shifting the print data by the shift register 240 having different lengths for each nozzle, when the nozzle rows are arranged obliquely with respect to the paper transport direction, the print data of the print data is printed so as to be printed at the correct position. We are in control.

[0005]

In the print data control circuit of the conventional ink jet printing apparatus, the print data control circuit needs a shift register having a different length for each nozzle. Therefore, the number of nozzles of the printing apparatus is increased. A longer shift register is required as the length of the increased nozzle row in the paper feed direction increases. Therefore, for example, when the length of the nozzle array is doubled, the circuit amount of the shift register is quadrupled, and the circuit amount increases due to the increase in the number of nozzles, which leads to an increase in device cost.

According to the present invention, in the printing apparatus in which the nozzle rows are arranged obliquely with respect to the sheet conveying direction, even if the number of nozzles in the printing apparatus increases and the length of the nozzle rows in the sheet feeding direction increases, the cost increase is small. The purpose is to obtain an inexpensive print data control circuit.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a print data control circuit for shifting print data transferred from a higher-level device to a nozzle array arranged diagonally is provided with a shift register having a plurality of bit widths formed by using a RAM. It is characterized in that the print data control circuit is a combination of shift registers configured by using logic circuits having different lengths for each nozzle.

Further, by changing the shift length of the shift register according to the distance from the nozzle,
A circuit in which a plurality of bits of shift registers each having a different length for each bit, which is configured by using the logic circuit, is combined,
It is characterized by using the same circuit.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a block diagram of a print data control circuit of an inkjet printing apparatus according to an embodiment of the present invention.
In FIG. 1, reference numeral 100 is a host device, 110 is a print control circuit, 120 is a RAM, 130RAM control circuit, 140 is a shift register, 150 is a piezoelectric element drive circuit, and 160 is a piezoelectric element.

FIG. 5 shows the nozzle arrangement of the ink jet printing apparatus. Nozzles are 128 at √5 / 300 inch intervals
The nozzles are arranged on a straight line. This nozzle row is 1 in the horizontal direction with respect to the paper transport direction.
/ 300 inches, and the vertical direction is installed so as to be inclined at intervals of 2/300 inches. Printing is performed at a dot density of 300 dpi in both the vertical and horizontal directions by ejecting ink from the nozzle every time the paper moves by 1/300 inch.

FIG. 2 shows shift of print data according to the embodiment of the present invention. RAM shift register No. in FIG.
Numerals 1 to 32 are 4-bit width, lengths 4, 12, 20, ... 252b configured by the RAM 120 and the RAM control circuit 130.
32 shift registers of it.

The shift registers No. 1 to 32 are shift registers 140 each having a width of 4 bits and a length of 2, 4, 6, 8 bits which are composed of logic circuits. The print data transferred from the host device 100 is input to the RAM 120 having a 4-bit width corresponding to each nozzle of the print data control circuit. RA
M120 is initialized to "0" so as not to perform extra printing. The RAM control circuit 130 shifts the data in the RAM 120 by 1 each time the paper moves by 1/300 inch. The data output from the RAM 120 is input to the shift register 140, and at the same time, the print data is output from the shift register 140 to the piezoelectric element drive circuit 150.
This print data is latched by the piezoelectric element drive circuit 150, and when the print data is "1", the piezoelectric element 160 is driven and ink is ejected from the corresponding nozzle. When the latched print data is "0", the piezoelectric element 160 is not driven, so ink is not ejected.

After printing one dot, the data in the RAM 120 and the shift register 140 are shifted by one. Next, the paper is moved again by 1/300 inch, and the above is repeated to perform continuous printing. In this way, a 4-bit width RAM 120 and 1
A shift register 140 having a different 2-bit length for each nozzle
By shifting the print data by combining the above, it becomes possible to print the print data at the correct position even if the nozzle rows are arranged obliquely with respect to the paper transport direction.

In the RAM shift registers Nos. 1 to 32 with the 4-bit width RAM 120, the shift length of the shift register 140 by the logic circuit is all increased for each group of 4 nozzles by increasing the shift length by 8 bits each time the nozzle No. increases by 4. Since it can be the same, the circuit configuration is simple,
Design becomes easy.

[0015]

As described above, according to the present invention, a shift register configured by using a RAM for each plurality of nozzles and a shift register configured by using a logic circuit and having different lengths for each nozzle are combined, By using the print data control circuit that shifts the print data, most of the shift register can be configured by the RAM even when the number of nozzle rows increases, so an inexpensive printing device that suppresses the increase of the print data control circuit can be provided. It is possible to obtain.

Further, the shift length of the shift register formed by using the RAM is changed according to the distance from the nozzle, so that the shift register having a different length for each nozzle formed by using the logic circuit can be used. It is possible to use the same circuit for each nozzle group.

[Brief description of drawings]

FIG. 1 is a diagram showing a print data control circuit of an inkjet printing apparatus of the present invention.

FIG. 2 is a diagram showing a shift of print data in the inkjet printing apparatus of the present invention.

FIG. 3 is a diagram showing a print data control circuit of a conventional inkjet printing apparatus.

FIG. 4 is a diagram showing a shift of print data in a conventional inkjet printing apparatus.

FIG. 5 is a diagram showing a nozzle arrangement of an inkjet printing apparatus.

[Explanation of symbols]

Reference numeral 100 is a host device, 110 is a print control circuit, and 120 is R.
AM, 130 RAM control circuit, 140 shift register, 150 piezoelectric element control circuit, 160 piezoelectric element, 2
10 is a print control circuit, 240 is a shift register, 300
Is the head.

Claims (2)

[Claims] 1. A head having a nozzle row composed of a plurality of nozzles for ejecting ink droplets, a piezoelectric element for ejecting ink from the nozzle, and a piezoelectric element drive circuit for selectively driving the piezoelectric element. In the ink jet printing apparatus that has the nozzle rows obliquely arranged with respect to the paper conveyance direction and ejects ink from the nozzles to the paper to perform printing, the nozzles in which print data transferred from a higher-level device is obliquely arranged. The print data control circuit for shifting to the column is
A shift register having a plurality of bit widths configured by using M,
An inkjet printing apparatus comprising a print data control circuit in which a shift register configured by using logic circuits having different lengths for each nozzle is combined. 2. The shift length of the shift register is changed according to the distance from the nozzle to combine a plurality of shift registers having different lengths for each 1 bit configured by using the logic circuit. The inkjet printing apparatus according to claim 1, wherein the circuits are the same circuit.