JPH0645244B2 - Inkjet printer printing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printer provided with, for example, a mode for performing high-speed printing by reducing the number of dots by thinning it out in addition to a mode for performing normal printing. Regarding printing method.

2. Description of the Related Art Conventionally, an ink jet printer having an operation mode, that is, a so-called draft mode, in which dots constituting print contents are thinned out and ink is ejected to every other dot position, for example, has been put into practical use.

In such a draft mode of the ink jet printer, the printing contents are rough, but printing can be performed at high speed. Therefore, it is convenient to print in a draft mode for printing contents that do not require high resolution, because the waiting time is shortened.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-described conventional technique, in the draft mode, the number of dots is reduced as compared with the normal mode for printing, so that the amount of ink ejected per unit area of the recording paper is also reduced. It As a result, the background color of the recording paper or the like is exposed, and the overall print density is reduced. Especially when an image or the like is printed, the print result in the normal mode and the print result in the draft mode may give a completely different impression.

An object of the present invention is to provide a printing method for an inkjet printer, which solves the above problems and improves the printing quality when printing is performed with a reduced number of dots.

Means for Solving the Problems The present invention relates to a printing method for an inkjet printer that ejects ink in dots to perform printing. In the inkjet printer, a first mode in which printing contents are printed without thinning out the number of dots, and It is possible to select a second mode in which the number of dots is thinned out to make the print content rough and to print at a higher speed than the first mode. In the second mode, the amount of ink ejected for each dot can be set in the first mode. The print density of each print content,
A printing method for an ink jet printer, which is characterized in that the printing density is not reduced as compared with the printing density in the first mode.

Operation According to the present invention, the inkjet printer prints the print content without thinning the number of dots in the first mode such as a fine mode, and thins the number of dots to print the print content roughly and at a higher speed than the first mode. It is possible to selectively operate a second mode such as a draft mode in which the print content of the same size as that of the first mode, for example, is rough, that is, the number of dots is reduced to perform high-speed printing. When performing, if the amount of ink per dot is the same as that of normal printing, the total amount of ink ejected as a whole is reduced, and the print density is reduced. According to the present invention, when printing is performed with the number of dots reduced, the amount of ejected ink is increased. Therefore, high-speed printing with a reduced number of dots can be performed without reducing the print density of the print content.

Embodiment FIG. 1 is a block diagram showing a simplified configuration of an inkjet printer 1 which is an embodiment of the present invention. The inkjet printer 1 includes a mode changeover switch 8, a main control circuit 2, a drive power supply circuit 3, a drive control circuit 4,
The drive circuit 5 and the piezoelectric element 6 are included.

The mode changeover switch 8 is connected to the main control circuit 2, and according to the switching mode of the mode changeover switch 8, the main control circuit 2 performs normal mode (hereinafter referred to as fine mode) control and draft mode control. Switch and perform.

The main control circuit 2 performs drive control of a pulse motor or the like, input / output control of print data in the storage circuit 7, control of drive pulse signals of the drive control circuit 4, control of the drive power supply circuit 3, and the like. The drive power source circuit 3, the drive power source, the drive pulse signal from the drive control circuit 4, and the print data from the storage circuit 7 are supplied to the drive circuit 5, respectively.
The piezoelectric element 6 is driven by the output signal of the drive circuit 5, pressurizes the ink and ejects it from a nozzle (not shown),
Print.

FIG. 2 is a block diagram showing the configuration of the drive control circuit 4. The drive control circuit 4 includes an output circuit 11 and a counter 1.
2 and the like, and changes the pulse width of the drive pulse signal in accordance with the control signal from the main control circuit 2.

Control signals that are different between the fine mode and the draft mode are given from the main control circuit 2 to the output circuit 11. The output circuit 11 outputs, for example, 4-bit parallel signals P0 to P3 to the counter 12 according to the control signal. The counter 12 increases the count value n by the clock signal, with the value n0 represented by the parallel signals P0 to P3 as an initial value when the trigger signal Tr falls.

Signal RCO derived from counter 12 to drive circuit 5
Becomes low level from the fall of the trigger signal Tr until the count value n of the counter 12 becomes "15". Further, the signal RCO is sent to the terminal E of the counter 12 via the inverter 13.
It is also input to P. The counter 12 stops the counting operation when the terminal EP becomes high level, and holds the count value n at this time. The drive circuit 5 drives the piezoelectric element 6 while the signal RCO is at a low level.

FIG. 3 is a waveform diagram for explaining the operation of the drive control circuit 4. A case where the value n0 represented by the parallel signals P0 to P3 is, for example, "10" in the fine mode and is "4" in the draft mode will be described.

In FIG. 3, the operation in the fine mode is shown by a virtual line. When the trigger signal Tr shown in FIG. 2B falls, the counter 12 starts counting with the value n0 (FIG. 1A) represented by the parallel signals P0 to P3 as an initial value (FIG. 3C). . N in fine mode
Since 0 = 10, counting is performed until the count value n changes from “10” to “15”, that is, for the period T1.
During this period, the signal RCO becomes low level ((4) in the same figure).
FIG. 5 (5) is a diagram showing a mode of the piezoelectric element 6, and the piezoelectric element 6 is driven in the period T1 to eject ink.

Since n0 = 4 in the draft mode, counting is performed until the count value n changes from "4" to "15", that is, for the period T2, and the signal RCO becomes low level during this period ((4) in the figure). ). Therefore, the piezoelectric element 6 is driven in the period T2 longer than the period T1 ((5) in the figure), and a larger amount of ink is ejected than in the fine mode.

In this way, in this embodiment, the number of dots is reduced in the draft mode, compared to in the fine mode, for example, ink is ejected to every other dot position. However, as described above, one of the piezoelectric elements 6
Since the amount of ink ejected by each drive is increased, it is possible to prevent the print density from decreasing in the draft mode and improve the print quality.

FIG. 4 shows a driving power supply circuit 3 of the inkjet printer 1.
3 is a block diagram showing the configuration of FIG. The drive power supply circuit 3 includes, for example, a switching circuit 21, a differential amplifier 22, and a transistor 24.

The switching circuit 21 has two different levels of voltages V1 and V2.
Is supplied to the switching circuit 21 by the control signal from the main control circuit 2, for example, in the fine mode.
In the draft mode, the voltage V2 is switched to lead to the non-inverting input terminal of the differential amplifier 22. Differential amplifier 2
Negative feedback is applied to No. 2, which has a large internal impedance on the input side and functions as a buffer. The output of the differential amplifier 22 is given to the transistor 24 via the resistor 23,
Transistor 24 to which power supply voltage VD is applied to the collector
The power is amplified and output to the drive circuit 5.

The voltage V that is switched and output in the switching circuit 21
Since the electric power output to the drive circuit 5 is different corresponding to 1 and V2, the voltage level of the signal output from the drive circuit 5 changes. For example, if V1 <V2, the displacement amount of the piezoelectric element 6 in the draft mode becomes larger than that in the fine mode, and the ejected ink amount can be increased.

In this way, the print quality can be improved in the draft mode as in the case described above.

In the inkjet printer 1, the method of changing the pulse width of the drive pulse signal by the drive control circuit 4 and the method of changing the pulse voltage level of the drive pulse signal by the drive power supply circuit 3 have been described. Sufficient effect can be obtained with only one of them,
Both methods may be used. The amount of ink ejected may be controlled by another method.

Effect According to the present invention, when the inkjet printer performs the printing operation in the second mode, it prints the same printing content by, for example, thinning out the number of dots, as compared with printing the printing content in the first mode. Coarse printing is performed, and further, printing is performed at a higher speed than in the first mode by thinning out the number of dots. In the second mode, the amount of ink ejected for each dot is increased compared to that in the first mode. Even if the number is reduced, the total amount of ink ejected when printing the same print contents in the first and second modes is hardly reduced, and it is possible to prevent a decrease in print density and thus improve print quality. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a simplified configuration of an inkjet printer 1 according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a drive control circuit 4 of the inkjet printer 1, and FIG. 3 is a drive control. FIG. 4 is a waveform diagram for explaining the operation of the circuit 4, and FIG. 4 is a block diagram showing the configuration of the drive power supply circuit 3 of the inkjet printer 1. 2 ... Main control circuit, 3 ... Drive power supply circuit, 4 ... Drive control circuit, 5 ... Drive circuit, 6 ... Piezoelectric element

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Claims (1)

[Claims] 1. A printing method of an ink jet printer for ejecting ink in a dot shape for printing, wherein the ink jet printer prints a print content without thinning out the number of dots, and the printing by thinning out the number of dots. It is possible to select a second mode in which the contents are rough and print at a higher speed than the first mode. In the second mode, the amount of ink ejected for each dot is increased compared to that in the first mode, Print density of print content
A printing method for an ink jet printer, which is characterized in that the printing density is not lower than the printing density in the first mode.