JPH0477260A - Drive circuit of ink jet printer - Google Patents

Abstract

PURPOSE:To reduce the number of drive elements by driving a piezoelectric element in the time divided drive mode. CONSTITUTION:First a serial data signal 1 which is a print signal is entered in shift registers 3a,3b,3c... and then is shifted by a shift clock 2. If 'k' sets of data are shifted to their specified positions respectively and are stored in latch circuits 4a,4b,4c... by a latch signal 5. Next, a selector signal 7 is entered using a control circuit to set only a switching transistor 9a to 'ON' position and the remaining switching transistors 9b,9c... to 'OFF' position. Under this state, the switching transistors 8a,8b,8c... are turned ON or OFF based on print data retained in the latch circuits 4a,4b,4c...

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an inkjet printer that records characters, images, etc. on a recording medium.

[Prior art l] A conventional inkjet print head applies a print signal to a piezoelectric element to extend the piezoelectric element, and the dynamic pressure of the ink generated at this time causes ink droplets to fly out of the nozzle and onto the printing paper. It forms dots.

[Problems to be Solved by the Invention] However, in order to drive the piezoelectric element, the same number of drive elements as the piezoelectric elements are required, and the drive circuit becomes expensive.

The problem to be solved by the present invention is to provide an inkjet printer that can print using an inexpensive drive circuit with a reduced number of drive elements.

[Means for Solving the Problems] In order to solve the above problems, the present invention includes m drive elements for driving the piezoelectric elements, n diodes, n resistors, and k resistors. The piezoelectric element is characterized in that it includes a switch for selecting the piezoelectric element, and drives the piezoelectric element in a time division manner.

[Embodiment] FIG. 1 shows an embodiment of an inkjet printer according to the present invention. In Figure 1, 1 is a serial data signal, 2
are shift clocks, 3a, 3b, 3c, ... are m shift registers, 4a, 4b, 4c, ... are the same number of latch circuits as shift registers 3 that hold the outputs of the shift registers, and 5 is a latch circuit. 4 is a latch signal, 6 is a reset signal for latch circuit 4, 7 is a selector signal, 8a,
8b, 8C5... and 9a, 9b, 9C1 are m and 2 switching transistors, 10a, 10b,
10c,... and lla, 11b, llc,... and 12a, 12b, 12C... are n piezoelectric elements, 2
0a, 20b, 20cm=- and 21a, 21b, 21
c, and 2'2 a, 22b, 22c, ... are n resistors, 30a, 30b, 30c, ... and 31a,
31b, 31c, ..., and 32a, 32b, 32c
, ... are n diodes.

FIG. 2 is a time chart of FIG. 1 according to the embodiment of the present invention. The embodiment shown in FIG. 1 will be explained along with FIG. 2. First, serial data signal 1, which is a print signal, is sent to shift register 3.
a, 3b, 3C1, . . . and shifted by shift clock 2.

After the k pieces of data have been shifted to their respective predetermined positions, the latch signal 5 causes the latch circuits 4a, 4b, 4C
2... is stored. In other words, a, b shown in Figure 2
= Print signal at position c, ... (in this case, high
The h level shall be printed, and the OW level shall not be printed. ) are latch circuits 4a, 4b, 4c, respectively.
...is stored in...

Next, the selector signal 7 is inputted by a control circuit (not shown), and only the switching transistor 9a is turned on.
The remaining switching transistors 9b, 9c, . . .
is turned off. In this state, the switching transistors 8a, 8b, 8C1...
・ is turned on or off. To explain using the example of the time chart in FIG. 2, since the print data signals a and C held in the latch circuits 4a and 4C are for printing, the switching transistors 8a and 8C are turned on. At this time, the selector circuit 6 selects only the switching transistor 9a.
Since they are in the n state, it is the piezoelectric elements 10a and 12a that are charged and displaced (hereinafter referred to as driven).

Here, an example of a portion of the print head arranged in FIG. 3 is shown. The piezoelectric element 101 is displaced in the direction of the nozzle plate 102, and an ink droplet 105 is ejected from the nozzle 103 to be printed on the recording medium 104. With this print head, the piezoelectric element 1
Printing is performed at the positions where 0a and 12a are arranged.

Also, at this time, the print data signal is a signal that does not print, so
Switching transistor 8b is turned off and piezoelectric element 10b is not driven. Next, as shown in FIG. 2, the switching transistors 8a and 8C are turned on, and after a certain period of time, the reset signal 6 is input to reset the latch circuit 4. By resetting the latch circuit 4, the switching transistors 8a and 8C are turned off. Accordingly, the piezoelectric elements 10a and 12a are connected to the resistors 20a and 22a connected in parallel and the diode 3 connected in series.
It is discharged through 0a and 32a and returns to the state before being charged. At the same time as this piezoelectric element is driven, the next print data is stored in the shift registers 3a, 3b, 3C1, as described above. After the piezoelectric elements 10a and 12a are discharged, the latch signal 5 causes the shift register 3a to
The print data signals stored in 3b, 3C1, . . . are stored in latch circuits 4a, 4b, 4C1, . At the same time, only the switching register 9b is turned on by the select signal 7. Then, in the same way as described above, the switching register 8 is
a, 8b, 8C1... are turned on, and this time piezoelectric element 1
0b, llb, llc, . . . are driven. Thereafter, similar operations are performed sequentially to perform time-division driving twice.

Although the present invention does not show the relationship between the print data and the arrangement of the nozzles facing the piezoelectric element, it is possible to print at any position where the nozzles are arranged by determining the transfer order of the print data with respect to the nozzle arrangement. It's obvious.

Next, another example will be shown. FIG. 4 shows another embodiment of the invention. 40a, 40b, 40c.

are m analog switches, and 50 is a voltage supply terminal. In this embodiment, the print data signal is stored as described in the previous embodiment, and analog switches 40a, 40b, 40C1, . . .
Put it in n state. Next, by inputting a pulsed voltage to the voltage supply terminal 50 from a power supply (not shown), the piezoelectric element group is charged and printing is performed. In this case, the discharge occurs when the pulsed voltage applied to the voltage supply terminal 50 becomes a low potential, and the analog switches 40a, 40b, 40C1...
It is done through. Thereafter, similar operations are performed sequentially to perform time-division driving twice.

〔Effect of the invention〕

As explained above, by performing time-division driving, the number of drive elements required to drive the piezoelectric element can be reduced, and the cost of the drive circuit can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an inkjet printer of the present invention. FIG. 2 is a time chart diagram of the inkjet printer of the present invention. FIG. 3 is a diagram showing an example of a print head of an inkjet printer. FIG. 4 is a diagram showing another embodiment of the inkjet printer of the present invention. 8a, 8b, 8C...Switching transistor 9'a, 9b, 9.C...Switching transistor 10a, 10b, 10c, lla, 11b, llc, 1
2a, 12b, 12c ・Piezoelectric elements 20a, 20b, 20c, 21a, 21b, 21c, 2
2a, 22b, 22c ・Resistors 30a, 30b, 30c, 31a, 31b, 31c, 3
2a, 32b, 32c ・Diode or more

Claims (1)

[Claims] In order to print individual dots, nozzles are arranged in one row or in multiple rows, and n nozzles (n
is a natural number, n≧4) piezoelectric elements are arranged, the piezoelectric elements are driven by a driving element, and the printing liquid is discharged to the outside from the nozzle and recorded on a recording medium arranged in front of the exit opening of the nozzle. in an inkjet printer for driving the piezoelectric elements (m is a natural number, m≧2)
a driving element, a diode individually connected in series to the piezoelectric element, a resistor individually connected in parallel to the piezoelectric element, and k selection switches (k is a natural number, k≧2). 1. A drive circuit for an inkjet printer, comprising: driving the piezoelectric element in a time division manner.