JP2006111024A - Electric-charge control type inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric-charge control type inkjet printer capable of obtaining a stable and beautiful printing state by correcting the electric-charge amount of charged ink particles in a more precise and faster manner. <P>SOLUTION: The electric-charge control type inkjet printer is equipped with a charge-amount correcting means which reads the number of vertical dots and the character height of characters for printing through ink particles to be charged out of those ink particles enabled for landing and corrects an electric-charge amount from the electric-charge information of the charged ink particles based on corrected data which correspond to the number of the vertical dots and the character height of the characters previously stored in the memory means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a charge control type ink jet printer.

For example, as shown in FIG. 8, the charge control type ink jet printer includes a particle generating means 100 including a gun 101 and a nozzle 102, charging electrodes 200 and 200 as charging means, and deflection electrodes 300 and 300 as deflecting means. And a gutter 400, and a predetermined dot pattern is formed on the print target surface.
The particle generating means 100 generates ink particles having a predetermined particle diameter after ejection by applying a pulsation with a constant frequency to the ink flow ejected from the tip of the nozzle 102 by using a piezo element or the like. It is designed to fly in 400 directions.

The flying ink particles 500 include at least landable ink particles that land at a predetermined dot landing position by charging, and include thinned ink particles, which will be described later, as necessary.
The charging electrodes 200 and 200 are arranged for each landing possible ink particle of the printing information stored in the storage unit in advance while the landingable ink particle passes between the two charging electrodes 200 and 200 among the generated ink particles. The charged ink particles are charged to a charge amount according to the charging information.

  The deflection electrodes 300 and 300 are charged by an electrostatic field formed between the deflection electrodes 300 and 300 while passing between the deflection electrodes 300 and 300 provided to face the charged ink particles charged between the charging electrodes 200 and 200. Deflection is performed with a degree of deflection corresponding to the amount. That is, by changing the degree of deflection, the charged ink particles are landed on the corresponding landing positions on the print target surface to form a predetermined dot pattern on the print target surface.

Since the gutter 400 is not necessary for printing, it can receive the landable ink particles and the thinned ink particles that are not charged between the charging electrodes 200 and 200.
The ink received by the gutter 400 is collected by a collecting pump (not shown) and used for printing again, although not shown.

  The thinned ink particles improve the quality of printing by reducing the Coulomb force that works between charged ink particles and the difference in air resistance due to the density of charged ink particles flying forward toward the surface to be printed. Ink particles provided between the landable ink particles and the landable ink particles. In FIG. 8, reference numeral 600 denotes a detection electrode, which detects the charge of the charged ink particles charged between the charging electrodes 200 and 200 and is normally charged, or generates ink particles normally. It is inspected whether it is broken.

However, in the case of the method of reducing the difference in air resistance due to the coulomb force acting between the charged ink particles by the thinned ink particles as described above and the density of the charged ink particles flying forward toward the surface to be printed, it is sufficient. In order to exert the effect, it is only necessary to interpose as many thinned ink particles as possible between the charged ink particles and the charged ink particles. However, as the number of thinned ink particles increases, the more the ink is printed. Takes time and causes problems with printing speed.
Therefore, when the printing speed is taken into account, depending on the printing pattern, the charged ink particles may deviate from the target and land on the surface to be printed, which may result in poor printing.

For example, in the conventional charge control type ink jet printer shown in FIG. 9, first, characters of 3 vertical lines are printed with 32 dots, then characters of 2 vertical lines are printed with 16 dots along the way. In this example, in this example, among the dots constituting the character “0” in the arrow X portion in FIG. 9, the position of the dot located immediately above the vertical bar of the lower “K” character is: The lowermost dot of the vertical bar portion at the left end of “D” in the arrow Y portion is shifted downward from the horizontal dot.
The reason for the deviation of the character “0” is that the character “K” is printed below the character “0”. That is, as shown in FIG. 10A, the vertical bar portion of the character “K” is printed in the dot order of the lower D1 to D7, and then directly above the vertical bar portion of the character “0”. The dot D8 is printed. Therefore, in front of the charged ink particles for printing D8, seven charged ink particles for printing D1 to D7 are flying toward the surface to be printed, and the charged ink particles print the dots of D8. The air resistance applied to the ink particles is reduced, and as a result, the speed drop due to the air resistance of the charged ink particles for printing the dots of D8 is small. This is to land on the print target surface.

On the other hand, as shown in FIG. 10B, the cause of the deviation of the character “D” is that the vertical bar portion of “D” is printed in the order of D1 to D7. Since the charged ink particles for printing the dots D2 to D7 are successively flying toward the surface to be printed from the back of the ink, the charged ink particles for printing the dots of D1 by the Coulomb force received from the charged ink particles that follow the back Is pushed in the direction of the surface to be printed, and the flight speed is increased, and landing on the surface to be printed without being sufficiently deflected.
In addition, even when the number of vertical dots or the character height is changed, the Coulomb force or air resistance applied to the charged ink particles also changes due to the difference in the interval between the charged ink particles flying in the front and rear, and the landing position is shifted. This problem occurs.

Therefore, the voltage applied to the landable ink particles is corrected as much as possible by correcting the voltage applied to the landable ink particles from the charge amount (including the uncharged state) of the landable ink particles flying before and after the target landable ink particles. Such a method has already been proposed (see, for example, Patent Document 1).
However, when the above method is used, an accurate corrected charge amount cannot be obtained unless the charge amount of a large number of charged inks flying back and forth is searched and the corrected charge amount is calculated.

That is, in order to obtain an accurate correction charge amount, data calculation of a large number of charged ink particles must be performed, and there is a problem that the calculation takes too much time.
JP-A-10-86384

  In view of the above circumstances, an object of the present invention is to provide a charge control type ink jet printer that can stably obtain a clean printing state by correcting the charge amount of charged ink particles more accurately and at high speed.

  In order to achieve the above object, a charge control type ink jet printer according to the present invention comprises particle generation means for continuously ejecting ink particles including at least landable ink particles that land on a predetermined dot landing position by charging. Charging means for charging the landable ink particles ejected from the particle generating means to a charge amount according to the charging information for each landable ink particle of the printing information stored in the storage means in advance, and charged charging ink In an inkjet printer comprising a deflecting means for deflecting particles and forming a predetermined dot pattern on the surface to be printed, the number of vertical dots and characters of characters to be printed by the target ink particles to be charged among the landable ink particles The height is read from the printing information stored in the storage means, and the charging information of the target ink particles is stored in the memory. It is characterized in that it comprises a charging amount correction means for correcting the charging amount based on the correction data corresponding to the advance longitudinal dot number and character height of the stored character.

  In the charge control type ink jet printer of the present invention, the ink particles are composed of the landable ink particles and the thinned ink particles existing between the landable ink particles ejected before and after the ink particles. It is preferable to include a charge amount correction unit that corrects the charge amount of the charged ink particles based on correction data stored in advance in the storage unit according to the number.

  Since the charge control type ink jet printer according to the present invention is configured as described above, it is possible to stably obtain a clean printing state by correcting the charge amount of the charged ink particles more accurately and at high speed.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 shows a first embodiment of a charge control type ink jet printer according to the present invention.

As shown in FIG. 1, this charge control type ink jet printer (hereinafter referred to as “printer” only) 1c includes an ink particle generating means 2 comprising a gun 21 and nozzles 22 and a charging means as in the case of a conventional printer. The print head mechanism 6 including the charging electrodes 3 and 3, the detection electrodes 4 and 4, and the deflection electrodes 5 and 5, and the control unit 7 are provided.
The control unit 7 includes a main memory 71, a main CPU (central processing unit) 72, a print control CPU 73, a digital-analog conversion unit 74, and an amplification unit 75.

The main CPU 72 reads print data stored in the main memory 71, print dot number data of the print data, and print information such as character height setting data.
Then, the print control CPU 73 performs charging corresponding to each dot of each character on the basis of the charging voltage correction table T3 obtained empirically in advance according to the number of vertical dots and character height stored in advance in the print control CPU 73. Charged ink particles having a charge amount corrected by determining a charging voltage correction value for each ink particle and applying a voltage corrected according to the charging voltage correction value while the charging target ink particles P pass between the charging electrodes 3 and 3 It is supposed to be.

Specifically, the charging voltage correction table T3 is created in a multidimensional manner so that the correction amount for the air resistance and the Coulomb force is increased as the number of vertical dots is increased and is decreased as the character height is increased. It is like that.
As described above, the printer 1c determines the charge amount of each charged ink particle on the basis of the charge voltage correction table T3 that is empirically obtained in advance by setting the number of vertical dots and the character height. Therefore, the print quality can be improved by more appropriate correction.

FIG. 2 shows a second embodiment of the charge control type ink jet printer according to the present invention.
As shown in FIG. 2, this charge control type ink jet printer (hereinafter referred to as “printer” only) 1a is the same as the printer 1c except for the following configuration.

  That is, in the printer 1a, the main CPU 72 reads and reads the print data stored in the main memory 71 and the print information such as the vertical dot number data, thinning number data, and character height setting data of the print data. As shown in FIG. 3, the printing information is ejected immediately before ejecting the charging target ink particles P to be charged, and is set from the charging target ink particles P to the set reference number (8 in this embodiment). The number a of the landable ink particles A to be charged is 3 out of the number of the landable ink particles A and B that are at least three (in the case of FIG. 3A). 3 (b), and the non-charged non-charged particles existing between the charge target ink particles P and the landable ink particles A charged immediately before the charge target ink particles P. (0 in the case of FIG. 3 (a), in the case of FIG. 3 (b) 2 pieces) landable ink number of particles B b electrodeposition detecting a.

On the other hand, the print control CPU 73 sets a = 3 and b = 0 in the case of FIG. 3A based on the charging voltage correction table T1 which is obtained in advance and stored in advance in the print control CPU 73. In the case of the corresponding charging voltage correction value, FIG. 3B, the charging voltage correction value corresponding to a = 2 and b = 2 is determined, and the charging target ink particles P pass between the charging electrodes 3 and 3. In the meantime, charged ink particles having a corrected charge amount are applied by applying a voltage corrected in accordance with the charge voltage correction value.
In the charging voltage correction table T1, specifically, the correction corrects the shortage of the deflection amount. Therefore, the landing between the charging target ink particle and the landable ink particle A with respect to the reference charging voltage is performed. The smaller the number b of the possible ink particles B, that is, the smaller the interval between the chargeable ink particles and the landable ink particles A, the higher the charging voltage. Further, the increase ratio is created in a two-dimensional table so that the charging voltage is increased as the number a increases.

  As described above, the printer 1a corrects the charge amount of the charged ink particles using the predetermined charge voltage correction table T1 based on the two parameters of the number a and the number b. Correction can be made more accurately and at high speed so that the ink particles are landed at predetermined landing dot positions.

FIG. 4 shows a third embodiment of the charge control type ink jet printer according to the present invention.
As shown in FIG. 4, this charge control type ink jet printer (hereinafter referred to as “printer” only) 1b is the same as the printer 1a except for the following configuration.

  That is, in the printer 1b, the main CPU 72 reads and reads the print data stored in the main memory 71 and the print information such as the vertical dot number data, thinning number data, and character height setting data of the print data. From the printed information, as shown in FIG. 5, the set reference number ejected immediately after the charging target ink particles P to be charged out of the landable ink particles are ejected (in this embodiment, eight, but at least Among the landable ink particles C and D, which may be three or more), the number c of the landable ink particles C to be charged (7 in the case of FIG. 5A, in the case of FIG. 5B) 2) and the target ink particles P and the target ink particles C that are charged immediately after the target ink particles P. The number d (in the case of FIG. 5 (a) 0, in the case of FIG. 5 (b) 3 pieces) for detecting a.

Then, the print control CPU 73 sets c = 7 and d = 0 in the case of FIG. 5A based on the charging voltage correction table T2 which is obtained empirically in advance and stored in advance in the print control CPU 73. In the case of the corresponding charging voltage correction value, FIG. 5B, the charging voltage correction value corresponding to c = 2 and d = 3 is determined, and the charging target ink particles P pass between the charging electrodes 3 and 3. In the meantime, charged ink particles P having a corrected charge amount are applied by applying a voltage corrected in accordance with the charge voltage correction value.
In the charging voltage correction table T2, specifically, the correction corrects the shortage of the deflection amount. Therefore, the landing between the charging target ink particles and the landable ink particles C with respect to the reference charging voltage. The smaller the number d of possible ink particles D, that is, the smaller the distance between the chargeable ink particles and the landable ink particles C, the higher the charging voltage. Further, the increase ratio is created by a two-dimensional table so that the charging voltage is increased as the number c is increased.

  As described above, the printer 1b corrects the charge amount of the charged ink particles using the predetermined charging voltage correction table T2 based on the two parameters c and d. Therefore, the ink particles that can be landed can be corrected more accurately and at high speed so as to land at a predetermined landed dot position.

FIG. 6 shows a fourth embodiment of the charge control type ink jet printer according to the present invention.
As shown in FIG. 6, this charge control type ink jet printer (hereinafter referred to as “printer” only) 1d is the same as the printer 1a except for the following configuration.

  That is, in the printer 1d, the main CPU 72 reads and reads the print data stored in the main memory 71 and the print information such as the vertical dot number data, thinning number data, and character height setting data of the print data. As shown in FIG. 3, the printing information is ejected immediately before ejecting the charging target ink particles P to be charged, and is set from the charging target ink particles P to the set reference number (8 in this embodiment). The number a of the landable ink particles A to be charged is 3 out of the number of the landable ink particles A and B that are at least three (in the case of FIG. 3A). 3 (b), and the non-charged non-charged particles existing between the charge target ink particles P and the landable ink particles A charged immediately before the charge target ink particles P. In addition to detecting the number b (0 in the case of FIG. 3A, 2 in the case of FIG. 3B) of the number of ink particles B that can be landed with electricity, as shown in FIG. The number e of thinned ink particles E is detected between the particles A (B).

Then, the print control CPU 73 determines charging voltage correction values corresponding to the number a, the number b, and the number e based on the charging voltage correction table T4 that is obtained empirically in advance and stored in the printing control CPU 73 in advance. The charged ink particles having a corrected charge amount by applying a voltage corrected according to the charging voltage correction value while the charging target ink particles P pass between the charging electrodes 3 and 3 are used.
The charging voltage correction table T4 is created in a multidimensional manner so that the amount of correction for air resistance and Coulomb force decreases as the number of thinned ink particles E increases.

  As described above, the printer 1d previously creates a charging voltage correction table T4 in which the number e of thinned ink particles E is added as a parameter to the two parameters a and b, and the charging voltage correction table T4 is created. Since the charge amount of the corresponding charged ink particles is corrected by using the charged ink particles, it is possible to land the charged ink particles more accurately on the target landing position and obtain a clean printing state with no deviation.

The present invention is not limited to the above embodiment. For example, a multidimensional table may be created by combining all parameters.
In the above embodiment, the correction of the charge amount is processed by software by the print control CPU. However, a part or all of the correction may be performed by hardware.

1 is a schematic diagram schematically illustrating a first embodiment of a charge control type ink jet printer according to the present invention. FIG. 5 is a schematic diagram schematically showing a second embodiment of the charge control type ink jet printer according to the present invention. FIG. 3 is a schematic diagram schematically showing an example of a flight pattern at a deflection electrode portion of landable ink particles using the printer of FIG. 2. FIG. 6 is a schematic diagram schematically showing a third embodiment of the charge control type ink jet printer according to the present invention. FIG. 5 is a schematic diagram schematically showing an example of a flight pattern at a deflection electrode portion of landable ink particles using the printer of FIG. 4. FIG. 10 is a schematic diagram schematically illustrating a fourth embodiment of the charge control type ink jet printer according to the present invention. FIG. 4 is a schematic diagram schematically showing an example of a flight pattern of thinned ink particles. FIG. 10 is a schematic diagram schematically showing an example of a conventional charge control type ink jet printer. It is a figure showing an example of the printing pattern of the conventional charge control type inkjet printer. It is a figure explaining the shift | offset | difference of the dot of the printing pattern of FIG.

Explanation of symbols

1a, 1b, 1c, 1d Charge control type ink jet printer 2 Particle generation means 3 Charging electrode (charging means)
5 Deflection electrodes (deflection means)
7 Controllers A, C Chargeable ink particles B, D Uncharged landable ink particles P Ink particles to be charged

Claims (2)

Particle generating means for continuously ejecting ink particles including at least landingable ink particles that land at a predetermined dot landing position by charging, and the landing possible ink particles ejected from the particle generating means are stored in the storage means in advance. A charging means for charging to a charge amount according to the charging information for each landable ink particle of the printed information and a deflecting means for deflecting the charged charged ink particles, and a predetermined dot pattern is formed on the surface to be printed. In the inkjet printer to be formed,
The number of vertical dots and the character height of characters to be printed by the target ink particles to be charged among the landable ink particles are read from the print information stored in the storage means, and the charging information of the target ink particles is stored in the storage means. A charge control type ink jet printer comprising charge amount correction means for correcting a charge amount based on correction data corresponding to the number of vertical dots and character height stored in advance.   Correction data preliminarily stored in the storage means according to the number of thinned ink particles, the ink particles being composed of landable ink particles and thinned ink particles present between the landable ink particles ejected before and after the ink particles. The charge control type ink jet printer according to claim 1, further comprising a charge amount correcting unit that corrects a charge amount of the charged ink particles based on the charge amount.

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