JPH1120171A - Apparatus for correcting printing distortion of ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve print quality by recognizing characters, marks, etc., printed to an object by an image pickup apparatus, measuring a position of printed dots, obtaining a misregistration amount from a predetermined position, and reflecting to character signals. SOLUTION: A charged ink particle 25 flies in an electrostatic field formed by deflection electrodes 16, 17 and a deflection voltage power source 18 and is deflected thereby printing a moving object 20 to be printed. A character, mark or the like printed to the object 20 is picked up by a camera 24 after printed. A position of every dot of the printed character, mark or the like is obtained by a CPU 1 via a PIA 21 and a bus. The CPU 1 takes via the bus a reference dot position stored in a RAM 3, compares the position with the position of the printed dot, and obtains the amount of a distortion. A character signal correction voltage is obtained from the amount, and a character signal written to a video RAM 11 is corrected via the bus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing a printing distortion of an ink jet printer of a charge control system.

[0002]

2. Description of the Related Art As described in Japanese Patent Application No. Hei 7-9496, a conventional apparatus is designed to reduce a printing distortion caused by electrostatic repulsion acting on charged particles and reduce the distortion before and after the particles to be charged. The character signal is reflected by the combination of the presence or absence of the charged particles.

Further, as in Japanese Patent Application No. 5-133161, the distance from the tip of the nozzle to the printing object is measured, and the character signal and the deflection electric field intensity are controlled based on the printing distance and the height of the character to be printed.

[0004]

The above prior art is an effective technique for preventing charged particles from reducing the charge amount of the particles that are about to be charged. Controlling the character signal and the deflection electric field strength from the printing distance and the height of the character to be printed is an effective technique for reducing the printing distortion by making the height of the character to be printed uniform. However, it has not been possible to reduce the printing distortion caused by changing the use conditions such as the printing distance and the temperature.

[0005]

The gist of the present invention to solve the above-mentioned problems is that a pressurized ink is ejected from a nozzle, the nozzle is excited at a constant frequency, the ink is turned into particles at a constant cycle, and a step-like wave is formed. The ink particles give a charge by giving a character signal, deflect the charged particles by flying in a deflecting electrolysis, and form a character or a mark by moving an object to be printed almost at right angles to the direction of the deflection. An ink-jet printer characterized in that a photographing device recognizes a character or a mark printed on an object to be printed, measures a printed dot position, finds a deviation amount from a predetermined position, and reflects the deviation amount on a character signal. Printing distortion correction device.

[0006] Basic characters, marks, and the like are printed in advance, photographed by a photographing device, and dot positions are determined and stored. After printing on the print target, the image is taken by the imaging device to determine the dot position, the amount of deviation from the stored basic dot position is determined, and characters and marks to be printed from the next according to the amount of deviation. To be reflected in the character signal.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One 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, a CPU (Central Processing Unit) 1 controls overall control, and a ROM (Read Only Memory) 2
The program reads and interprets programs, data, and the like stored in the CPU and performs various processes. RAM (random access
Memory) 3 is a temporary storage register when the program proceeds,
It is a readable and writable storage device used as a data register or the like.

The CPU 1 exchanges various information via the bus 4. Reference numeral 5 denotes a first-in first-out register (hereinafter abbreviated as FIFO) for passing print dot matrix data used for printing. The selector 6 converts parallel data from the FIFO 5 into serial data. Control R
AM7 is for various devices (FIFO5, selector 6, etc.)
And outputs a signal for controlling. The transmitting circuit 8 has a CP
The clock of U1 or the timing of other various signals is generated.

The excitation amplifier 9 converts the clock generated by the transmission circuit 8 into an ink particle generation cycle and amplifies the clock. The shift register 10 shifts the data converted into a serial signal by the selector 6. The video RAM 11 is a RAM that stores a step-like character signal. The D / A converter 12 converts the video RA
It converts the digital value of the M11 output into an analog value. The video amplifier 13 amplifies the signal converted by the D / A converter 12 into an analog value. The charging electrode 15 is an electrode for applying the character signal amplified by the video amplifier 13 to the ink particles to charge them.

[0010] Pressurized ink is ejected from the nozzle 14, and an excitation signal amplified by the excitation amplifier 9 is applied.
The deflection electrodes 16 and 17 form an electrostatic field with the deflection voltage power supply 18. The ink particles are deflected by flying there. Thereby, the ink particles charged by the charging electrode 15 are deflected according to the amount of charge.

The particles not used for printing are collected in the gutter 19 and reused. Reference numeral 21 denotes a PIA, which interfaces with an external device, and 23, a sensor for detecting an object to be printed, which gives a print start command to an ink jet printer.

An input / output terminal (hereinafter abbreviated as a keyboard) 22 is used for setting various data. Printed object 2
0 indicates that printing is performed while moving in the direction of the illustrated arrow. The camera 24 is for photographing characters, marks, and the like printed on an object to be printed. Hereinafter, the operation will be described.

The keyboard 22 is used to preliminarily input the print content and print format, that is, the character height, the number of printing steps, the dot configuration (horizontal × vertical) of the character to be used, thinning, and the like. This content is transmitted to the CPU 1 via the PIA 21 and the bus 4.
Is stored in the RAM 3.

When a character signal is created based on this setting, the CPU 1 takes out a correction coefficient from the ROM 2 via the bus 4 and calculates the character signal, and the CPU 1 transfers the result to the video RAM 11 via the bus 4. 5 is written as before the correction. The correction coefficient here reduces print distortion due to a decrease in the amount of charge due to charged particles, electrostatic repulsion acting between ink particles, and a decrease in flight speed due to air resistance received during flight of the ink particles.

Next, a print start command is input from the print start sensor 23 and the printing process is started. The CPU 1 searches for desired print dot matrix data based on the print data that has been input first, and packs the data into the FIFO 5 in the order of printing.

The data output to the output port through the FIFO 5 is sequentially converted into serial data by the selector 6, and is converted into data in consideration of the presence or absence of particles used for printing before and after by the shift register 10. RAM
It is output as an address signal of the character signal data of No. 11.

The video RAM 11 outputs a corresponding character signal as a digital signal to the D / A converter 12 based on the address, is converted into an analog signal by the D / A converter 12, is amplified by the video amplifier 13, and is charged as a charging signal. It is applied to the electrode 15 to charge the ink particles 25. The charged ink particles 25 fly and deflect during the electrostatic solution formed by the deflecting electrodes 16 and 17 and the deflecting voltage power supply 18, and can print on the moving print target 20.

The characters and marks printed on the printing object 20 are photographed by the camera 24 after printing, and the dot positions of all the dots of the printed characters and marks are obtained by the CPU 1 via the PIA 21 and the bus 4. . Further, the CPU 1 retrieves a reference dot position as shown in FIG. 2 stored in the RAM 3 via the bus 4 and compares it with the dot position of the printed result to obtain a distortion amount as shown in FIG. A character signal correction voltage as shown in FIG. 3 is obtained from the amount, and the character signal written to the video RAM 11 via the bus 4 is corrected as shown in FIG.

As a result, the printing distortion as shown in FIG. 4 which is different depending on the use condition is corrected, and the printing as shown in FIG. 5 in which the print distortion is reduced under any use condition becomes possible from the next printing. The above-mentioned reference dot position as shown in FIG. 2 is printed in advance, photographed by the camera 24, and the CPU 1 obtains the dot pitch via the PIA 24 and the bus 4 and stores it in the RAM 3.

[0020]

According to the present invention, printing in which print distortion that differs depending on the use conditions has occurred can be corrected in accordance with the use conditions, thereby enabling printing with reduced print distortion. That is, high print quality can be realized under any use conditions.

[Brief description of the drawings]

FIG. 1 is a control block diagram.

FIG. 2 shows a position measurement of a basic pattern.

FIG. 3 shows a distortion amount and a character signal.

FIG. 4 is a printing example before correction.

FIG. 5 is a character signal applied to ink particles.

FIG. 6 is a printing example after correction.

[Explanation of symbols]

1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... Bus, 5 ...
FIFO, 6 ... selector, 7 ... control RAM, 8
... Transmission circuit, 9 ... Excitation amplifier, 10 ... Shift register,
11 ... Video RAM, 12 ... D / A converter, 13 ...
Video amplifier, 14 ... nozzle, 15 ... charged electrode, 16,
17: deflection electrode, 18: deflection voltage power supply, 19: gutter,
Reference numeral 20: print substrate, 21: PIA, 22: keyboard, 2
3: print start sensor, 24: camera, 25: ink particles.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor: Etsio Niimi 1-1-1, Higashitagacho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division

Claims (3)

[Claims] 1. A method according to claim 1, wherein the pressurized ink is ejected from a nozzle, the nozzle is excited at a constant frequency, the ink is granulated at a constant cycle, and a stepwise wave-like character signal is applied to the ink particle to impart a charge. In an ink jet printer that forms charged characters and marks by moving charged particles in a direction substantially perpendicular to the direction of deflection, the charged particles are deflected by flying the charged particles during deflection electrolysis. A print distortion correction device for an ink jet printer, comprising means for recognizing the position and measuring the position of a printed dot. 2. A printing method according to claim 1, wherein a printing position is stored in advance, and a shift amount from a printed dot position is calculated, and is reflected on a character signal such as a character or a mark to be printed next according to the calculated amount. A print distortion correction device for an ink jet printer that reduces print distortion by causing the print distortion to be reduced. 3. A print distortion correcting apparatus for an ink jet printer according to claim 1, wherein a character signal set for each print condition is updated in accordance with use conditions to reduce print distortion.