JP2936744B2 - Inkjet printer distortion correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A distortion correction device for an ink jet printer of this type uses a charge signal correction coefficient for reducing print distortion (a print position is deviated from a target position) as disclosed in Japanese Patent Application Laid-Open No. 1-97659. The correction coefficients are set to be different depending on the vertical dot position information and the thinning information.

[0003]

However, in this prior art, a huge amount of data is required if the correction coefficients are determined for all the vertical dots. Also, if the number of vertical dots is set to be equal to or more than a certain number of vertical dots, the correction becomes rough, and fine grain correction cannot be performed.

[0004] It is an object of the present invention to enable fine grain correction with minimum data.

[0005]

The present invention focuses on the relationship between the vertical dot configuration and print distortion (print position shift), and
Since the upper dot and lower dot of one character are easily distorted, the correction coefficient for these easily distorted dots and the correction coefficient for the other dots are set separately, and in the case of multi-stage printing in which multiple lines are printed at the same time, In particular, since the dots in the space between the rows between rows are easily distorted, the correction coefficients for the dots are set separately.

[0006]

In order to charge the ink particles, step-like data is generated, and the step-like data is corrected by a correction coefficient in advance and used for printing. When creating staircase waveform data, the position of the target dot is always counted, and if it is determined in advance that the dot position is liable to be distorted, correction is performed using a predetermined correction coefficient.

By setting an independent correction coefficient in a place where distortion is likely to occur, fine distortion correction can be performed with minimum data.

[0008]

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

FIG. 1 is a block diagram of the control device. Reference numeral 1 denotes a CPU (Central Processing Unit) that controls the entire system.
It reads and interprets programs, data, and the like stored in an M (read only memory) 2 to perform various control processes. 3 is a RAM (random access memory),
This is a readable and writable storage device used as a temporary storage register, a data register, and the like when a program proceeds. C
The PU 1 sends and receives various information via the bus 6. 5 is a first-in first-out register (hereinafter FI)
Abbreviated as FO. ) Mediates the transmission of print dot matrix data used for printing. A selector 8 converts parallel data output from the FIFO 5 into serial data. Reference numeral 10 denotes a shift register for shifting data converted into a serial signal by the selector 8. Reference numeral 4 denotes a PIA (Peripheral Interface Adapter) having a parallel output port. 7 is a total dot counter (the number of vertical dots in the matrix) +
(The number of play dots) is counted.

Reference numeral 11 denotes a transmission circuit which generates various timing signals in addition to the clock signal of the CPU 1. A dot counter 13 is a counter for counting vertical dots. Reference numeral 14 denotes a video RAM, which stores staircase wave signals (output terminals D0 to D7). Reference numeral 15 denotes a control RAM, which outputs signals for controlling various devices (the FIFO 5, the selector 8, and the like).

The AND gate 16 gates the staircase signal output from the video RAM 14. Reference numeral 17 denotes a D / A converter, which converts a digital value into an analog value and supplies the analog value to a video amplifier 18. The video amplifier 18 amplifies the video signal and generates a charging signal to the charging electrode 20. Pressurized ink is ejected from the nozzle 19, and an excitation signal amplified by an excitation amplifier 27 is applied to the nozzle 19. As a result, the ejected ink is regularly turned into particles (ink particles 25) inside the charging electrode 20, and charged. The ink particles 25 are formed on the deflection electrode 21,
While flying in the electrostatic field formed by the high voltage source 22 and the high voltage source 23, the light is deflected according to the amount of charge and adheres to the printing surface. And
Ink particles not used for printing are collected by the gutter 24 and accumulated for reuse. Reference numeral 28 denotes a PIA, which interfaces with an external device. Reference numeral 29 denotes a print start sensor which detects the arrival of an object to be printed and generates a print start command. An input / output terminal 30 is used for setting various data. The printing object 26 is printed on its printing surface while moving in the direction of the arrow.

Next, an example of distortion and an outline of correction will be described with reference to FIGS. FIG. 2A shows a character shape when ideal printing without distortion is performed. In this example, two-stage printing is performed, and the distortion that is often seen is the distortion as shown in FIG. If this distortion is classified by the position of the vertical dot, it can be classified into Condition 1 to Condition 7. That is, the condition 1 indicates the uppermost dot at the top.

Condition 2 indicates the second dot from the top in the uppermost row.

Condition 3 indicates the second dot from the bottom in the uppermost row.

Condition 4 indicates the lowest dot at the top.

Condition 5 indicates the second dot from the bottom in the lowermost row.

Condition 6 indicates the lowest dot at the bottom.

Condition 7 indicates dots other than conditions 1 to 6.

FIG. 3 shows conditions for three-stage printing.
The second dot from the bottom of the middle row has condition 3, and the first dot from the bottom of the middle row has condition 4.

FIG. 4 shows the conditions when the number of vertical dots is 16 in one-stage printing. In the case of one-stage printing, conditions 3 and 4 are eliminated.

FIG. 5 shows front and rear dots to be considered under each condition. a indicates that it is before the front, b is the front, c is the rear, and d is that of the dot after the rear.

FIG. 6 shows a list of correction coefficients under the conditions 1 to 7. When creating a staircase wave, it is checked which condition corresponds, and the calculation is performed according to the calculation procedure of FIG.

Next, returning to FIG. 1, the operation of this embodiment will be described. First, print contents are input in advance using the input / output terminal 30. This content is stored in the RAM 3 by the CPU 1 via the PIA 28. In addition, the print format, that is, the character height, the number of printing steps (one of one-step printing to four-step printing), the size of the matrix to be used (horizontal × vertical 5 × 7 dots or 12 × 16 dots) Is set using the input / output terminal 30. When a staircase wave is created based on this setting, the calculation is sequentially performed according to the calculation procedure of FIG. 6 while determining which of the conditions 1 to 7 the current step corresponds to. CP
U1 sends the result to the video RAM 14 via the bus 6.
Write to

Next, when a print start command is input from the print start sensor 29, the process proceeds to a printing process. The CPU 1 searches for the desired print dot matrix data based on the print data that has already been input, and fills the FIFO 5 in the order of printing. In the case of the present embodiment, the bit width of the FIFO 5 is 8 bits. The data output to the output port through FIFO5 is
The data is sequentially converted into serial data by the selector 8. Outputs C0, C1, and C2 of the FIFO 5 are output terminals of a select signal for extracting one bit from 8-bit data. The shift register 10 has a parallel output (Q
A to QD), of which the output QC is used as bit data for printing. That is, shift register 1
An output QC of 0 is a terminal for outputting print matrix data to be printed. Other outputs QA, QB, QD, Q
E is used as a select signal of the video RAM 14.
The corrected staircase wave data is written in the video RAM 14 in advance, and is read out by the dot counter 13 in ascending order of steps of the staircase wave. At this time, the outputs QA, QB, QD,
A staircase wave corrected by QE is output.

The total dot counter 7 counts all the dots in one row, and clears the dot counter 13 at the end of deflection scanning for one row. All the counters used in the present embodiment operate in synchronization with the clock signal CK from the transmission circuit 11.

The video RAM 14 stores dot counts in the vertical direction and outputs QA, QB, QD, and Q of the shift register 10.
The staircase wave data corresponding to the address signal from E
The signal is output to the D gate 16. In this way,
A digital video signal is output from the AND gate 16,
It is converted into an analog signal by the D / A converter 17, amplified by the video amplifier 18, generates a charging signal to be applied to the charging electrode 20, and charges the ink particles 25. The charged ink particles 25 are deflected by an electrostatic field generated by the deflection electrodes 21 and 22, and perform printing on the printing surface of the printing object 26.

[0027]

According to the present invention, the tendency of occurrence of distortion is classified for each dot position in the vertical direction of printing, and when the tendency of appearance of distortion is similar, the coefficients are integrated and arranged to set the optimum. With the configuration in which the correction coefficient is selected to correct the charge amount, the printing distortion can be reduced by performing the optimum correction with a small amount of correction coefficient data.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control device according to the present invention.

FIG. 2 is an explanatory diagram of printing dots in a case where there is a character distortion in two-stage printing and in a case where there is no character distortion.

FIG. 3 is an explanatory diagram of conditions for three-stage printing.

FIG. 4 is an explanatory diagram of conditions when the number of vertical dots is 16 in one-stage printing.

FIG. 5 is an explanatory diagram of dots before and after to be considered in each condition.

FIG. 6 is an explanatory diagram of a correction coefficient under conditions 1 to 7;

[Explanation of symbols]

1 CPU, 2 ROM, 3 RAM, 4 PIA, 5
.. FIFO, 7 total dot counter, 8 selector, 10 shift register, 3 dot counter, 14
... Video RAM, 15 ... Control RAM, 19 ... Nozzle, 20 ... Charging electrode, 21 ... Deflecting electrode, 22 ... Deflecting electrode, 23 ... High voltage source, 25 ... Ink particles, 26 ... Printed object, 29 ... Print start sensor, 30 ... I / O terminal.

Claims (2)

(57) [Claims] An ink jetting nozzle for jetting pressurized ink is vibrated at a constant frequency, the ink jetting from the nozzle is turned into particles at a constant period, and a stepwise charging signal is applied to a charging electrode to charge the ink particles. To cause the charged ink particles to fly in a deflecting electric field, thereby deflecting in the y-direction, and relatively moving the object to be printed substantially at right angles to the deflection in the y-direction. The tendency of distortion occurrence is classified for each dot position in the vertical direction of printing, and when the tendency of distortion is similar, the coefficients are integrated and arranged to set the type of correction coefficient, and the type of correction coefficient is set according to the correction coefficient. A distortion correction device for an ink jet printer, wherein a charge signal is generated. 2. An ink jet printer according to claim 1, wherein a plurality of lines are printed by one nozzle, the recognition of the dot position is performed for each dot position in the line, and the tendency of distortion generation is classified. A distortion correction apparatus for an ink-jet printer, wherein coefficients having similar tendencies are integrated and arranged, and a type of correction coefficient is set.