JPH0197659A - Distortion correction device for ink-jet printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for correcting printing distortion of an inkjet printer using a charge deflection control method.

[Conventional technology]

As a conventional distortion correction means, for example, USP-3,562
, 757' and Japanese Patent Laid-Open No. 57-103852, one or more dummy particles used for printing are inserted between ink particles used for printing to prevent interference between particles. Many methods were used to prevent and prevent distortion.

[Problem that the invention seeks to solve]

Since the above-mentioned conventional technology has a structure in which dummy particles are unconditionally inserted between printing particles, there is a problem that the printing speed is extremely reduced.

An object of the present invention is to provide a distortion correction device for an inkjet printer that can prevent printing distortion, improve the utilization rate of ink particles, and increase printing speed.

[Means for solving problems]

The above object is to have a print dot matrix data group to be used for printing in an inkjet printer using a charge deflection control method, and when creating a print signal using the matrix data, each charged particle of a plurality of particles before and after a charged particle is A means for increasing/decreasing the charge amount of a charged particle by using the sum of the respective amounts multiplied by correction coefficients as a correction value, and a plurality of the above correction coefficients are prepared, and the vertical dot position information of the charged particle and a plurality of numbers before and after the charged particle are prepared. means for switching the correction coefficient according to the information on whether the particles are charged or not, and further according to the information on whether or not an operation for thinning out the particles by inserting uncharged particles between the printed dots is performed. This can be achieved by adopting a configuration that

[Effect]

When printing is performed by repeatedly scanning from bottom to top for each column in the vertical direction and then moving to the bottom of the next column, the influence of particles at the top of a character on the bottom of the next column, and the influence of particles in one column of characters. This is naturally different from the influence of the particles before and after near the center. Therefore, distortion can be reduced by determining the correction coefficient in consideration of both the position of the vertical dot and the charge status of the particles before and after the particle.

In addition, we focused on the fact that when printing one line, the ink particles that are deflected more, that is, the upper part of the vertical dots, are more distorted. If the value exceeds this value, the dot usage rate is reduced, that is, thinning is performed by inserting uncharged particles between printed dots to reduce distortion. At the same time, by determining the correction coefficient in consideration of this utilization rate, even higher quality printing can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a control block diagram of the embodiment. In Fig. 1, numeral 1 is a CPU (central processing unit), which is in charge of overall control, and a ROM (read-only memory) 2.
It reads and interprets programs, data, etc. stored in the computer, and performs various processes.

3 is a RAM (random access memory), which is a readable and writable storage device used as a temporary storage register, data register, etc. when a program is running. C
The PUI exchanges various information via the bus 6. 5
is a first-in first-out register (hereinafter abbreviated as FtFo), which is used to pass print dot matrix data used for printing. 8 is a selector that converts parallel data from F+Fo5 into serial data. A shift register 10 is used to shift data converted into a serial signal by the selector 8. 4 is PIA (peripheral interface adapter)
It is a parallel output port.

7 is a total dot counter that counts (number of vertical dots in the matrix) + (number of uncharged particles) + (number of idle dots). 9 is an uncharged particle counter that counts the number of dots during printing of one vertical column. This is to count how many uncharged particles have been used.

Reference numeral 12 denotes a comparator, which determines whether or not the uncharged particles in the drug used have reached the initial setting value.

A latch 31 is used to temporarily store the timing at which uncharged particles are required. AND gate 33 is for creating data to be given to latch 31, NOT
The gate 32 is for initializing counters and latches. Reference numeral 11 denotes an oscillation circuit that generates the timing of the clock of the CPU 1 and various other signals. A dot counter 13 is a counter for counting vertical dots.

14 is a video RAM, which receives a staircase wave signal (output terminal Do-0
7) and an uncharged particle presence/absence signal (output terminal D8). A controller RAM 15 outputs signals for controlling various devices (FIFO 5 + selector 8, etc.).

The AND gate 16 is for gating the staircase wave signal output from the video RAM 14.

A D/A converter 17 converts the digital value into an analog value and supplies it to the video AMP 18. Video AMP1
8 amplifies the video signal and applies a charging signal to the charging electrode 20. Pressurized ink is ejected from the nozzle 19, and an excitation signal amplified by the excitation AMP 27 is applied. As a result, the ink particles 25 are turned into particles inside the charging electrode 20 and charged. Deflection electrodes 21, 22 and high pressure source 2
The ink droplet is deflected while flying through the electrostatic field formed by the ink droplet and the ink droplet. Further, unused particles are collected in the gutter 24 and reused. 28 is a PIA, which interfaces with external equipment; 29 is a print start sensor, which gives a command to the inkjet printer to start printing. 30 is an input/output terminal, which is used when setting various data. Printing is performed while the printing object 26 is moving in the direction of the arrow shown.

Next, 1. Before entering into an explanation of the operation of the embodiment, an example of distortion and an outline of correction will be explained using FIGS. 2 to 4.

FIG. 2(a) shows an ideal character shape without distortion.

This example is two-stage printing, and the distortion that is usually seen is
As shown in FIG. 2(b), in the upper row of characters, dots are continuous in the vertical direction, and the dots tend to occur at the bottom O and the top 2 of the continuous dots. Also, in the lower row, distortion occurs at the ○ due to the influence of () and at the O due to the influence of ■. In two-stage printing, if both the upper and lower rows are printed using all dots without thinning, the actual situation is that the upper row does not produce characters and correction is hardly effective. Therefore, in this embodiment, all the dots are used in the lower row, and uncharged particles are inserted between the printed dots in the upper row to thin out the dots.

Furthermore, information on the presence or absence of charges of multiple particles before and after the charged particle,
The amount of charge of the charged particles is corrected using the optimum correction coefficient according to the longitudinal dot position information and the information on the presence or absence of thinning.

FIG. 3 shows an example of a correction coefficient in two-stage printing in this embodiment, and FIG. 4 shows a method of calculating all charging voltages.

In FIG. 3, the correction coefficients α and β are applied in order from the first dot in the lower row to the one with the largest deflection amount.

Indicates γ. α is a correction coefficient by which the charging voltage of the preceding particle should be multiplied, β is a correction coefficient by which the charging voltage of the preceding particle should be multiplied, and γ is a correction coefficient by which the charging voltage of the subsequent particle should be multiplied.

Same coefficient symbol in the figure.

means the same coefficient. Further, this coefficient can be freely set and changed, and it is not the case that only this combination can be used.

Among these, the following points are major features of this embodiment. That is, in the case of this example, the upper stage and the lower stage are divided into those with and without uncharged particles. Therefore, in the upper and lower rows,
The correction coefficients are significantly different. Further, the coefficient α0 of the first dot in the lower row is a different coefficient from the coefficient αl of the third dot. This means that α0 of the 1st dot in the lower row is the 6th dot in the upper row of the front row.
The coefficient to be multiplied by the dotted Vze is 3.
Since α1 of the dot is a coefficient to be multiplied by the VLl of the first dot in the lower row of the same column, it serves to reduce distortion due to discontinuous charging voltage. β0 and 2 of the first dot in the lower row
The reason why βl of the dotted line is a different coefficient is due to the same reason. With this correction, co and do in FIG. 2(b)
Can lift dots.

In the calculation shown in FIG. 4, as a matter of course, if there is no charged particle at the position α, the term α becomes zero, and the correction amount is not added. Coefficient β.

The same applies to γ.

Next, referring back to FIG. 1, the operation of this embodiment will be explained. First, the content to be printed is input in advance using the input/output terminal 30. This content is transferred to CP via PIA28.
It is stored in RAM3 by the UI. Next, a print start command is received from the print start sensor 29, and printing processing begins. C.P.U.I.
In this embodiment, the bit width of the FiFo is 8 bits. The data output to the output port through the selector 8 is sequentially converted into serial data. The terminal C3 of the FiFo5 is for reading instructions, and the terminals Co, C1, C2 of the selector 8 are for reading instructions.
This is a select signal terminal for extracting one bit from the bit data. The shift register 10 has parallel outputs (Q^ to Qo), of which QB is used as a printing bit. In other words, the Q of the shift register 10
B is where the print matrix data to be printed is output. Other Q^v Qc e Qo is video RAM
14 is used as a select signal. Eight types of staircase wave data are written in advance by the CPU in the video RAM 14, and are read out in order from the smallest step of the staircase wave by the dot counter 13. At this time, the Q^v Qc of the shift register 10 described above A staircase wave whose charge amount has been corrected by the QD is output. At the same time, the output terminal D8 of the video RAM 14 outputs information on whether or not to perform 1-thinning. When this terminal is "1", it indicates that there is thinning out, and when this terminal is "0", it indicates that there is no thinning out. The total dot counter 7 counts all the dots for one column, and the timing at which scanning for one column ends can be recognized from the carry output CA. 1
At the end of scanning the column, the uncharged particle counter 9. Latch 31.
All dot counters 13 are cleared. The uncharged particle counter 9 is a counter that counts only when uncharged particles are used. This counter 9 is enabled to count only when the terminal T input is II II II.

The condition for the terminal T input to be "1" is when the output of the AND gate 33 is "1". The comparator 12 compares the A input and B input, and when the surface inputs are equal, the A=B terminal is set to “
1'''. The Q^ ratio output of the latch 31 is normally "1". In this state, when the D8 output of the video RAM 14 becomes "1", that is, when an uncharged particle instruction is issued, the AND The output of the gate 33 becomes "1", which allows the uncharged particle counter 9 to count.

The latch 31 takes in the output of the AND gate 33 from the terminal A, and outputs it to the Q^ terminal after latching.

If the terminal A input is “1”, the Q^ terminal after latching is “1”.
The latches and counters used in this embodiment all operate in synchronization with the clock multiplier CK from the oscillation circuit 11.The A terminal of the comparator 12 has a P
The set value of the number of uncharged particles output from terminals PBO to PB3 of 4 is input to terminal I, while the number of uncharged particles used in one row of scanning is input to terminal B of uncharged particle counter 9. It is given from terminals Q^ to Qo. Uncharged particles can be inserted into a column until the surface inputs are equal. The Q^ ratio output of the latch 31 is input to the AND gate 16, and when this bit is "1", an uncharged particle is inserted. Furthermore, when an uncharged particle is inserted, the T input of the dot counter 13 also becomes "1", and this counter 13 does not advance.
Q.

The corresponding staircase wave data is AN by the address signal from
It is output to the D gate 16. In this way A
A digital video signal is output from the ND gate 16, converted to an analog signal by the D/A converter 17, amplified by the video AMP 18, and applied to the charged electrode 20.
The ink particles 25 are charged. Charged ink particles 25
is deflected by the electrostatic field created by the deflection electrodes 21 and 22.

Printing can be performed on the printing object 26.

〔Effect of the invention〕

According to the present invention, the amount of charge is corrected by selecting the optimum correction coefficient according to the charge state information of plural particles before and after the charged particle and the vertical dot position information, thereby eliminating the need of the prior art. Unlike the method of inserting dummy particles into the conditions, printing distortion can be reduced while maintaining high-speed operation. Furthermore, it is easy to configure the dot usage rate to be changed from a specific vertical dot position, and by providing a correction coefficient commensurate with this dot usage rate, printing distortion can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram of an embodiment of the present invention, and FIG. 2 (
a) and (b) are diagrams showing a comparison between cases without and with character distortion, Figure 3 is a diagram showing the relationship between vertical dots and correction coefficients in the example, and Figure 4 is a diagram showing the relationship between vertical dots and correction coefficients in the example, and Figure 4 shows charging using the correction coefficients. FIG. 3 is a diagram showing a voltage calculation method. 1...CPU, 2...ROM, 3...RAM, 4
, 28... PIA, 5... F+Fo, 7... Total dot counter, 8... Selector, 9... Uncharged particle counter, 10... Shift register, 12...
Comparator, 13... Dot counter, 14... Video RAM, 15... Control RAM, 19...
Nozzle, 20... Charging electrode, 21.22... Deflection electrode, 23... High pressure source, 25... Ink particle, 26...
...Printed object, 29...Print start sensor, 30...
Input/output terminal, 31...Latch. 2nd B (σ,) Positive candlelight i-2nd step a';
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x +l/// 1 /λVz6 ” Vzbs +
Vzt ・tAλ+ VB'13z + To7
．． trVzs= Vzss 10Vz3・tlz +
Vzt-1jz1,000l/zr・hvzt= vzismoV
22'mez + Vx31z + VzS・and IVzs
= Vt3s + Vzt, rlz -t Vzz゛ノz+1/2t-p(Vn = Vns'r Vtq
-tlz 士Vzt゛fiz ”r Vz3J+Vzt
:= V:zts -? Vtb-c12-t
Vt71z + Vlz-FtV/7・Vtri! ;＋
V/S-ku r-+V (6zo/10V21・tOVtb=
Vm + Vtt-tit −+ Vts・)37
10V/7・/. Vts = V15s + Vta-tt + Vta・I
B7 10V/6゛/”.

Claims (1)

[Claims] 1. A nozzle to which ink pressurized at a constant pressure is supplied is excited with an excitation voltage of a constant frequency, and the ink ejected from the nozzle is regularly atomized in synchronization with the frequency, and the ink is A charging signal is applied to a charging electrode placed along the path of the particles in accordance with the timing at which the ink particles are generated, giving the ink particles an electric charge proportional to the charging signal, and by controlling the deflection of the charged ink particles, a charge signal is applied to the recording paper. An inkjet printer that draws a print pattern consisting of a collection of print particles has a print dot matrix data group to be used for printing, and when creating a print signal using this matrix data, it is necessary to A means for increasing or decreasing the charge amount of a charged particle by using the sum of each charge amount multiplied by a correction coefficient as a correction value, and a plurality of correction coefficients are prepared, and the vertical dot position information of the charged particle and the charge amount of the charged particle are prepared. A distortion correction device for an inkjet printer, comprising means for switching the correction coefficient according to information on the presence or absence of charge of a plurality of particles before and after the particles. 2. The means for switching the correction coefficient is based on the vertical dot position information of the charged particle, information on the presence or absence of charge of multiple particles before and after the charged particle, and thinning by inserting uncharged particles between printed dots. 2. The distortion correction device for an inkjet printer according to claim 1, wherein the correction coefficient is switched depending on presence/absence information.