JP2006239861A - Inkjet printer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer device which uniforms the volume variation in ink droplets depending on a discharge frequency owned by an inkjet head, and by which a uniform printing density can be obtained even if the variation in the discharge frequency, i.e., the variation in the moving speed of a printing object occurs. <P>SOLUTION: For this inkjet printer device, the inkjet head 101, a discharge trigger pulse generating device 20, a frequency counting circuit 102 which counts a discharge trigger pulse, a control circuit 103, a frequency couple driving voltage table 104 which is referred from the control circuit, and a variable voltage power source circuit 105 which is controlled by the control circuit are provided. In this case, the discharge trigger pulse generating device 20 generates the discharge trigger pulse of a specified number conforming to a moving distance of the printing object. When the discharge frequency has changed resulting from the change in the moving speed of the printing object, a head driving voltage 10d compensated in response to the change in the discharge frequency is fed to the inkjet head, and the uniform printing density is obtained even when the moving speed of the printing object has changed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for controlling a piezoelectric drive type ink jet head, and an ink jet printer apparatus using the control method.

  As a prior art in the technical field of the present invention, for example, there is an ink jet printer apparatus as shown in FIG.

In FIG. 4, an inkjet head 101 is a piezoelectric drive type inkjet head, and ink is supplied from the ink storage container 30 to the inkjet head 101 through the ink supply path 10f.
The print data generation circuit 40 generates a print data signal 10e to be printed on the print object 60 and outputs it to the inkjet head 101.
The discharge trigger pulse generator 20 is a sensor that generates a predetermined electric pulse according to, for example, the rotation angle, generates a predetermined number of discharge trigger pulses 10 a according to the moving distance of the print object 60, and outputs it to the inkjet head 101. To do.

  The ink jet head 101 discharges ink droplets 50 at a discharge pattern synchronized with the discharge trigger pulse 10a based on the input print data signal 10e, and prints a predetermined image on the print object 60.

  The power supply circuit 115 is a drive voltage source that drives a piezoelectric element built in the inkjet head 101, and outputs a head drive voltage 10 d to the inkjet head 101.

In such an ink jet printer apparatus, as an example of a method for keeping the discharge characteristics stable and uniform, the above-described power supply circuit 115 is used as a variable voltage source, and the drive voltage 10d is changed in accordance with a change in the ambient environmental temperature to change the discharge characteristics. An apparatus configured to perform correction is disclosed in Patent Document 1.
Japanese Patent Application Laid-Open No. 07-148920 (page 11, FIG. 5)

  In the conventional inkjet printer described above, when the moving speed of the printing object changes during printing and the ejection frequency changes, the volume of the ink droplets ejected by the inkjet head varies according to the ejection frequency. As a result, there is a problem that the print density is uneven and the print quality is lowered.

  An object of the present invention is to uniformize the volume variation of the ink droplets depending on the ejection frequency of such a conventional inkjet head, and to maintain a uniform print density even if the ejection frequency changes, that is, the movement speed of the printing object changes Is to provide an inkjet printer apparatus.

In order to achieve the above object, the present invention provides an inkjet head, a discharge trigger pulse generator for generating a discharge trigger pulse having a predetermined frequency according to the moving distance of a printing object, a frequency counting circuit for counting the discharge trigger pulse, and a control A circuit, a frequency vs. drive voltage table referenced from the control circuit, and a variable voltage power supply circuit controlled by the control circuit,
The ejection trigger pulse generator outputs ejection trigger pulses to the inkjet head and the frequency counting circuit, and the frequency counting circuit counts the frequency of ejection trigger pulses input from the ejection trigger pulse generator and controls the control circuit. The discharge trigger frequency data is output to the control circuit, and the control circuit refers to the drive voltage corresponding to the discharge trigger pulse frequency data input from the frequency counting circuit from the frequency-to-drive voltage table and supplies the drive voltage to the variable voltage power supply circuit. A control signal is output, and the variable voltage power supply circuit outputs a head drive voltage to the inkjet head based on the drive voltage control signal.

  According to such a configuration, when the moving speed of the print object changes and the discharge frequency changes, the head drive voltage corrected according to the change of the discharge frequency is supplied to the inkjet head, and the moving speed of the print object Even when the value changes, a uniform print density can be obtained.

  As described above, the present invention makes the ink droplet volume variation dependent on the ejection frequency of the inkjet head uniform, and a uniform print density can be obtained even when the ejection frequency changes, that is, the movement speed of the print object changes. This has the effect that an ink jet printer apparatus can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
In FIG. 1, an ink jet head 101 is a piezoelectric drive type ink jet head, and ink is supplied from the ink reservoir 30 to the ink jet head 101 through the ink supply path 10f.
The print data generation circuit 40 generates a print data signal 10e and outputs it to the inkjet head 101.
The discharge trigger pulse generator 20 generates a discharge trigger pulse 10 a and outputs it to the inkjet head 101 and the frequency counting circuit 102.
The frequency counting circuit 102 counts the ejection trigger pulse 10 a output from the ejection trigger pulse generator 20 and outputs ejection trigger frequency data 10 b to the control circuit 103.
The control circuit 103 refers to the frequency versus drive voltage table 104 based on the ejection trigger frequency data 10 b and outputs a drive voltage control signal 10 c to the variable voltage power supply circuit 105.
The variable voltage power supply circuit 105 outputs a head drive voltage 10d to the inkjet head 101 in accordance with the drive voltage control signal 10c.
The ink jet head 101 discharges ink droplets 50 at a discharge pattern synchronized with the print pattern based on the input print data signal 10e, the ink droplet volume based on the head drive voltage 10d, and the discharge trigger pulse 10a, and onto the print object 60. Print a predetermined image.

An embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, a discharge trigger pulse generation device 20 is a pulse generation device such as a rotary encoder, for example, and is mechanically coupled to a conveyance device 70 to generate discharge trigger pulses 10a at predetermined intervals according to the moving distance of a print object 60. . Since the ink-jet head 101 ejects the ink droplet 50 in accordance with the ejection trigger pulse 10a, the printing dot interval is kept constant even when the moving speed of the printing object 60 changes, so that a normal print image can always be obtained. It has become.

  On the other hand, the ejection trigger pulse 10a is also input to the frequency counting circuit 102 at the same time. For example, the frequency every 0.1 second is sampled and output to the control circuit 103 as ejection pulse frequency data 10b. The control circuit 103 refers to the corrected head drive voltage 10d corresponding to the ejection pulse frequency data 10b from the frequency-to-drive voltage table 104 and outputs it to the variable voltage power supply circuit 105 as the drive voltage control signal 10c. The variable voltage power supply circuit 105 outputs a head drive voltage 10d based on the drive voltage control signal 10c to the inkjet head 101.

Here, the frequency versus drive voltage table 104 will be described with reference to FIGS.
FIG. 2 is a graph showing an example of a change in the volume of the ink droplet with respect to the ejection frequency of the inkjet head 101. FIG. It is the correction | amendment drive voltage graph calculated | required by these.
In FIG. 2, when the ejection frequency is changed by, for example, Δf from f1 to f2 while the driving voltage of the inkjet head is kept constant, the volume of the ejected ink droplets is from m1 to m2.
And Δm changes.
On the other hand, using the corrected drive voltage graph of FIG. 3, for example, the drive voltage v1 is applied to the head at the discharge frequency f1, and the drive voltage v2 is applied to the head at the discharge frequency f2. In this way, it is possible to control the ink droplet volume to be a predetermined value with respect to the fluctuation of the ejection frequency. The correction drive voltage graph as shown in FIG. 3 is stored in a storage device such as a memory as drive voltage values for every 0.1 kHz, for example, and is referred to as the frequency versus drive voltage table 104 from the control circuit 103.

1 is a configuration diagram of an ink jet printer apparatus according to the present invention. Graph showing an example of frequency characteristics of an inkjet head The graph which shows an example of the frequency versus drive voltage table which concerns on this invention Configuration diagram of a conventional inkjet printer device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet printer apparatus 101 of this invention Inkjet head 102 Frequency counting circuit 103 Control circuit 104 Frequency vs. drive voltage table 105 Variable voltage power supply circuit 115 Power supply circuit 10a Discharge trigger pulse 10b Discharge trigger frequency data 10c Drive voltage control signal 10d Head drive voltage 10e Print data signal 10f Ink supply path 20 Discharge trigger pulse generator 30 Ink storage container 40 Print data generator circuit 50 Ink droplet 60 Print object 70 Conveyance device

Claims (2)

  An ink jet comprising: an ink jet head for recording on a recording medium; an ejection trigger pulse generating device for generating a predetermined number of ejection trigger pulses according to a moving distance of the recording medium; and a variable voltage power supply circuit for driving the ink jet head. In the printer apparatus, a head drive voltage correction unit is provided that corrects the head drive voltage output from the variable voltage power supply circuit in accordance with the frequency of the discharge trigger pulse output from the discharge trigger pulse generator. Inkjet printer device Inkjet head for recording on a recording medium, an ejection trigger pulse generator for generating a predetermined number of ejection trigger pulses according to the moving distance of the recording medium, a frequency counting circuit for counting the ejection trigger pulse, and the inkjet head A variable voltage power supply circuit for driving, a control circuit for controlling the variable voltage power supply circuit, and a frequency vs. drive voltage table referenced from the control circuit,
The ejection trigger pulse generator outputs ejection trigger pulses to the inkjet head and the frequency counting circuit, and the frequency counting circuit counts the frequency of the ejection trigger pulse input from the ejection trigger pulse generator and performs the control. The discharge trigger frequency data is output to the circuit, and the control circuit refers to the drive voltage corresponding to the discharge trigger pulse frequency data input from the frequency counting circuit from the frequency versus drive voltage table and to the variable voltage power supply circuit. An inkjet printer apparatus that outputs a drive voltage control signal.

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