JP2010017981A - Inkjet recording apparatus - Google Patents

Abstract

To provide an ink jet recording apparatus capable of easily determining an optimum nozzle driving voltage for forming ink particles without requiring skill.
The control unit does not energize the deflection electrode until the ink particles enter the gutter after the ink particles are charged from the charging electrode, and arbitrarily sets the nozzle driving voltage a plurality of times. Charge is applied to the particles at an arbitrary charging voltage, and the amount of charge applied to the ink particles is detected by a charge amount sensor. If the charging voltage and the charge amount of the ink particles are in a proportional relationship, it is determined to be normal. Is set as the nozzle driving voltage used for printing.
[Selection] Figure 3

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus including a nozzle that forms ink particles with an optimum nozzle driving voltage.

  In general, in an ink jet recording apparatus of a charge control type, ink is ejected from the nozzles as ink particles due to nozzle resonance caused by the nozzle drive voltage (see, for example, Patent Document 1). At this time, the ink particles ejected from the nozzles are visually observed with a magnifying glass while changing the nozzle driving voltage, and the nozzle driving voltage when the ink particle shape is suitable for printing is determined as the optimum nozzle driving voltage, or There is a method in which characters are actually printed while changing the nozzle drive voltage, and a human determines that the median value of the nozzle drive voltage range in which good printing has been performed is the optimum nozzle drive voltage.

JP2007-136839

  However, according to the above method, the ink particles ejected from the nozzles are visually observed with a magnifying glass, and it is necessary to be an expert to accurately determine the shape of ink particles suitable for printing. There is a problem of making a difference. Further, when printing is actually performed, there is a problem that a workpiece is wasted, or that a human being visually determines a printing result, thereby causing individual differences.

  An object of the present invention is to provide an ink jet recording apparatus capable of easily determining an optimum nozzle driving voltage for forming ink particles without requiring skill.

  To achieve the above object, a nozzle drive circuit that applies a nozzle drive voltage to a nozzle that ejects ink particles, a charging electrode that charges a character signal to the ejected ink particles, and ink charged by the charging electrode Controls a deflection electrode that deflects the flying direction of particles, a charge amount sensor that measures the amount of charge of ink particles charged by the charging electrode, a nozzle drive circuit, a charging electrode, a charging electrode, a deflection electrode, and a charge amount sensor In the continuous ink jet recording apparatus provided with the control unit, the control unit does not energize the deflection electrode until the ink particles enter the gutter after the ink particles are charged from the charging electrode. The nozzle driving voltage is arbitrarily set a plurality of times, the ink particles are charged with an arbitrary charging voltage, and the charge amount given to the ink particles is set to the charge amount sensor. Detected by the sub, the charge amount of the charge voltage and the ink particles in the case of proportional judged to be normal, is set as the nozzle drive voltage used for printing the median of nozzle drive voltage range determined to be normal.

  As described above, according to the present invention, it is possible for a beginner to easily determine an optimum nozzle driving voltage without requiring skill, and stable printing can be performed.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the illustrated example.

  FIG. 1 is a configuration diagram of an ink jet recording apparatus 100. A main ink container 1 is provided in the ink jet recording apparatus 100, and the main tank container 1a is filled with ink 2a. The main ink container 1 includes a supply valve 3, a supply pump 4, The main filter 5, the pressure regulating valve 6, the ejection valve 7, and the nozzle 8 are connected to the ink supply pipe 9. A charging electrode 23 and a deflection electrode 24 are arranged in the traveling direction of the ink particles 10 ejected from the nozzle 8, and the ink particles 10 used for printing are charged with a voltage corresponding to the character signal by the charging electrode 23. Then, it flies in the electric field created by the deflection electrode 24, is deflected according to the amount of charge, reaches the substrate 26, and forms characters, symbols, and the like. A gutter 11 for collecting the ink particles 10 that are not used for printing is disposed in the traveling direction of the ink particles 10 that are not used for printing among the ink particles 10 ejected from the nozzles 8.

  The gutter 11 is connected to the charge amount sensor 25 that measures the charge amount of the charged ink particles 10 via the ink recovery tube 13, the recovery pump 12, and the main tank container 1. When the ink particles 10 are collected by the gutter 11, the ink particles 10 and the surrounding air are simultaneously taken in and transported to the main ink container 1. The air conveyed to the main ink container 1 passes through the external exhaust pipe 22 connected to the main ink container 1 from the exhaust port (not shown) provided in the ink jet recording apparatus 100 to the outside of the ink jet recording apparatus 100. It is supposed to be discharged.

  The ink jet recording apparatus 100 includes a sub ink container 14, and the sub ink container 14 is filled with ink 2b. The sub ink container 14 is connected to the replenishing valve 3 and the supply pump 4 via the ink supply pipe 16.

  Further, the ink jet recording apparatus 100 is provided with an intensifying liquid container 17, and the intensifying liquid container 17 is supplemented with the intensifying liquid 18. The intensifying fluid container 17 is connected to the intensifying pump 19 and the intensifying valve 20 through the intensifying fluid refilling pipe 21.

  As shown in FIG. 14, the inkjet recording apparatus 100 includes an MPU 32 (microprocessing unit) that controls each part inside the inkjet recording apparatus 100 via a bus 200. The MPU 32 includes an inkjet recording apparatus. RAM 30 (random access memory) that temporarily stores data in 100, ROM 29 (read only memory) that stores programs in advance, video RAM 31 that stores video data to be charged to ink particles 10, and charging signals for video data The charge signal generation circuit 27, the charge amount sensor 25, the charge amount amplification circuit 28 that amplifies the signal of the charge amount sensor 25, and the nozzle drive circuit 33 for driving the nozzle 8 are connected. It comes to control.

  In addition, the MPU 32 is connected to the supply valve 3, the nozzle 8, the supply pump 4, the recovery pump 12, the booster fluid pump 19, the supply valve 3, the pressure regulating valve 6, the ejection valve 7, the supply valve 15, the auxiliary valve 15 through the bus 200. The force valve 20, the charging electrode 23, the deflection electrode 24, and the operation display unit 300 are connected, and the MPU 32 controls these operations.

  Next, the operation when printing is described. When performing printing, the supply pump 4, the recovery pump 12, and the intensifying fluid pump 19 are operated according to the signal input from the operation display unit 300, and the supply valve 3 and the ejection valve 7 are opened, and the pressure regulating valve 6 Regulated to an arbitrary pressure.

  Then, a nozzle drive voltage is applied to the nozzle 8 from the nozzle drive circuit 33, and ink is ejected from the nozzle 8. A charging voltage is applied to the charging electrode 23 from the charging signal generation circuit 27 to the ink particles 10 ejected from the nozzle 8, and the ink particles 10 are charged by the charging electrode 23. The charged ink particles 10 are deflected in the flight direction by the electric field generated by the deflection electrode 24, and land on the work for printing. Fly in the direction of ink particles 10 that are not used for printing. The ink particles 10 captured by the gutter 11 are sucked by the collection pump 12 and collected in the main container 1 through the collection pipe 13.

  Here, the ink is atomized by the ink pressure pulsation in the nozzle 8 by the nozzle driving voltage and the surface tension of the ejected ink. Here, the shape of the ink particles 10 is influenced by the magnitude of the nozzle drive voltage, and affects the print quality.

  Hereinafter, a process for determining an optimum nozzle driving voltage will be described with reference to the flowchart of FIG.

  First, the voltage of the deflection electrode is set to “0V” (step S1). This is to prevent a situation in which the charged ink particles 10 are not collected by the gutter 11 from when the ink particles 10 are charged until the ink particles 10 enter the gutter 11. Next, the count number in which the nozzle drive voltage applied to the nozzle 8 is set by the nozzle drive circuit 33 is confirmed (step S2). Next, a nozzle drive voltage is set according to the number of times the nozzle drive voltage is set (step S3). Specifically, taking FIG. 13 as an example, the minimum drive voltage of 20V is set for the first time. Then, the drive voltage is set so that the nozzle drive voltage is increased by 2V according to the number of times, such as 22V for the second time. Thereafter, the drive voltage set by the nozzle drive circuit 33 is applied to the nozzle 8 to cause the ink particles 10 to be ejected, and the ink particles 10 ejected from the nozzle 8 are particles for one vertical printing (8 in this embodiment). A charge is applied to each of them in the order of discharge from the nozzle 8 as shown in FIG. 4 (step S4).

  Next, the charge amount of each ink particle 10 is measured by the charge amount detection sensor 25 (step S5), the signal of the measurement result is amplified by the charge amount amplification circuit 28, and each ink particle 10 is charged based on the amplified signal. The relationship between the voltage and the charge amount is stored in a table in the RAM 30 (step S6). This table is, for example, a table 1 as shown in FIG. 12, and stores the charge amount measured from the ink particles 10 with respect to the charging voltage applied to the ink particles 10 by the charging electrode 23.

  Here, when the ink particles 10 are normally charged, the charging voltage and the charge amount of the ink particles 10 have a proportional relationship as shown in FIG. When the applied charging voltage and the output result of the charge amount sensor 25 are in a proportional relationship, the output of the charge amount sensor 25 becomes larger for the ink particles 10 to be discharged later. Since it increases with a certain size, a straight line (hereinafter referred to as an ideal printing straight line) as shown in FIG. 6 is formed. The ideal proportional relationship between the charging voltage and the charge amount in this embodiment is that the measurement result of each ink particle 10 falls within the range corresponding to the ideal print line ± 1 dot pitch, as shown in FIG. 6, for example. State. This is because when the measurement result falls within the range corresponding to the ideal print line ± 1 dot pitch, there is little possibility that the actually printed characters are misread. Note that the dotted line above the ideal print line shown in FIG. 6 is the upper limit value of the allowable range, and the dotted line below the ideal print line is the lower limit value of the allowable range. This also applies to FIGS. 8 and 9 described later.

  FIG. 7 shows the printing position when the measurement result of each ink particle 10 is within the range corresponding to the ideal printing straight line ± 1 dot pitch as shown in FIG. The black circle on the solid line is an ideal printing position, and the range from 1 pitch upward to 1 pitch downward is the allowable range when printing is actually performed.

  When the charging voltage and the charge amount are not in a proportional relationship, even one of the measurement results of the ink particles 10 falls outside the range corresponding to the ideal print line ± 1 dot pitch, for example, as shown in FIG. Since printing in this case is out of the allowable range, as shown in FIG. 10, the result of printing is out of the ideal print position ± 1 dot bit range, which is the allowable range of the print position, and there is a risk of misreading. .

  The charging voltage stored in the table 1 in the RAM 30 and the charge amount are proportional to each other, that is, all the measurement results of the ink particles 10 by the charge amount sensor 25 are shown by the upper dotted line and the lower dotted line shown in FIG. Is determined (step S7), and the determination result is stored in the table 2 shown in FIG. The table 12 stores a result for each charging voltage for charging each ink particle 10 with the charging electrode 23 (step S8). That is, when the measurement result is within the range between the upper dotted line and the lower dotted line shown in FIG. 6, that is, when the measurement result is normal, “◯”, and the measurement result is within the range between the upper dotted line and the lower dotted line shown in FIG. If not, that is, if abnormal, “x” is stored in the table 12 in the RAM 30.

  Next, it is determined whether or not the current determination result is “×” (step S9). If the determination result is “◯” (NO), the process returns to step S2. When the determination result is “×” (YES), it is determined whether or not the determination result of “◯” has been continued twice or more immediately before the result of the current determination (step S10). If it is determined that it is not continuous twice or more (NO), the process returns to step S2. If it is determined that it is continuous twice or more (YES), the median value of the nozzle drive voltage value of the determination result of “◯”, that is, 30V is determined as the optimum drive voltage by taking FIG. 13 as an example ( Step S11), and then printing is started. When the determination of “◯” continues only twice, the average value of the drive voltages determined as “◯” is set as the nozzle drive voltage.

  It should be noted that the measurement may be continued even when “X” is determined after “O” is continuously determined. As such, if measurement is continued and “O” is determined after “X” after continuous “O” is determined, measurement is continued until “X” is determined again. . This is because the measurement accuracy of the charge amount sensor 25 may vary. The nozzle drive voltage used for printing in this case is an average value of the nozzle drive voltage first determined to be “◯” and the last nozzle drive voltage determined to be “◯”.

  As described above, according to the invention according to the present embodiment, an optimum nozzle driving voltage is automatically determined, so that even a beginner can easily work. Also, stable characters and the like can be printed by automatically determining the optimum nozzle drive voltage.

  If the charging voltage is high, normal charges are not applied to the ink particles 10 as shown in FIG. 9, and the actual printing range does not fall within the allowable range as shown in FIG. Therefore, a predetermined charge is applied to the ink particles 10 only at the maximum value of the charging voltage or at one or more charging voltages near the maximum value, and the charge amount is measured to be normal (the charge amount corresponding to the charging voltage). If it is normal, X may be stored in table example 2 if not normal.

It is a schematic block diagram of the inkjet recording device concerning a present Example. 1 is a functional block diagram of an ink jet recording apparatus according to an embodiment. It is a flowchart for determining the nozzle drive voltage of the invention concerning a present Example. It is an example of the charging voltage signal in a present Example. It is a figure showing the relationship between the normal charging voltage and the charge amount sensor output. Charge amount detection signal when the device of the present invention is normal Printing position of the device of the present invention It is an example of the charge amount detection signal at the time of abnormality. It is an example of the charge amount detection signal at the time of abnormality. It is a printing result in the case of FIG. FIG. 10 is a printing result in the case of FIG. 9. It is an example of the table in which a measurement result is stored. It is an example of the table in which the determination result is stored.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main ink container, 2 ... Ink, 3 ... Supply valve, 4 ... Supply pump, 5 ... Main filter, 6 ... Pressure regulating valve, 7 ... Injection valve, 8 ... Nozzle, 9 ... Supply pipe, 10 ... Ink particle, 11 DESCRIPTION OF SYMBOLS ... Gutter, 12 ... Collection pump, 13 ... Collection pipe, 14 ... Sub ink container, 15 ... Supply valve, 16 ... Supply pipe, 17 ... Reinforcement liquid container, 18 ... Reinforcement liquid, 19 ... Reinforcement liquid pump, 20 ... Reinforcement valve, 21 ... Reinforcement supply pipe, 22 ... Exhaust tube, 23 ... Charging electrode, 24 ... Deflection electrode, 25 ... Charge amount sensor, 26 ... Printed object, 27 ... Charge signal generation circuit, 28 ... Charge amount amplification Circuit, 29 ... ROM, 30 ... RAM, 31 ... Video RAM, 32 ... MPU, 33 ... Nozzle drive circuit, 100 ... Inkjet recording apparatus, 200 ... Bus

Claims (2)

A nozzle driving circuit for applying a nozzle driving voltage to a nozzle for ejecting ink particles; a charging electrode for charging a character signal to the ejected ink particles; and a deflection electrode for deflecting the flying direction of the ink particles charged by the charging electrode. A continuous-type inkjet comprising: a charge amount sensor that measures the amount of charge of the ink particles charged by the charging electrode; and a controller that controls the nozzle drive circuit, the charging electrode, the charging electrode, the deflection electrode, and the charge amount sensor. In the recording device,
The controller does not energize the deflection electrode until the ink particles enter the gutter after charging the ink particles from the charging electrode, and arbitrarily sets the nozzle driving voltage a plurality of times. Charge is applied to the particles at an arbitrary charging voltage, and the amount of charge applied to the ink particles is detected by the charge amount sensor.If the charging voltage and the amount of charge of the ink particles are in a proportional relationship, it is determined as normal. An ink jet recording apparatus, wherein a median value of nozzle drive voltages in a range determined to be present is set as a nozzle drive voltage used for printing.   The ink jet recording apparatus according to claim 1, wherein the control unit sets a nozzle driving voltage used for printing when the determination that the measurement result by the charge amount sensor is normal continues.

Images