JP2007181959A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder capable of retaining good printing quality by improving performance of an ink particle, reducing a charging voltage and reducing a flying distance. <P>SOLUTION: This inkjet recorder includes a deflection electrode having a slit section capable of avoiding collision of an ink particle to the deflection electrode corresponding to the deflection amount of the ink particle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs high-quality printing by ejecting ink particles continuously with a deflection electrode having a high deflection capability.

  In order to achieve high-quality printing as an inkjet recording device that continuously ejects ink particles onto a printed object to be conveyed, in order to reduce the influence of the Coulomb repulsive force on the printing, It is necessary to reduce the distance between the ink particles, that is, to increase the flight trajectory of the ink particles. Further, in order to reduce the influence of air resistance on printing, it is indispensable to shorten the flight distance.

Japanese Patent Laid-Open No. 2000-962

  In order to achieve high print quality, it is necessary to reduce the charge amount of ink particles, shorten the flight distance, and increase the flight trajectory of particles. First, regarding the reduction in the amount of charge of ink particles, it is necessary to reduce the charging voltage applied in order to reduce the Coulomb repulsive force generated between the ink particles. However, since the deflection amount of the ink particles is proportional to the charging voltage, if the charging voltage applied to the ink particles is reduced, the deflection amount of the ink particles is reduced, and the dot matrix-like character is formed at the lowest position. In order for the dots to be discharged, that is, the ink particles having the lowest charging voltage, not to jump over the gutter and jump over the gutter with a low charging voltage, it is necessary to keep the position of the gutter away from the deflection electrode. By moving the position of the gutter away, the flight distance of the ink particles increases, and even if the Coulomb repulsive force can be reduced, the print quality is affected by the increase in air resistance. Further, in order to reduce the influence of the air resistance on the printing quality, the flight distance must be shortened by bringing the position of the gutter closer to the deflection electrode. However, as the position of the gutter approaches, the top particle will not be able to jump over the gutter unless the charging voltage is increased, and this will increase the effect on printing due to the increase in the charging voltage even if the effect of air resistance can be reduced. End up. To reduce the charging voltage and shorten the flight distance, increase the deflection electrode length, increase the ink particle deflection capability, print low charge ink particles at short flight distance, and high deflection It is required to expand the flight trajectory between particles by ability. However, if the deflection ability of the ink particles is increased, the deflection amount of the topmost particle, that is, the ink particle having the highest charge, in forming the dot matrix character is further increased, and the positive deflection electrode is formed. The problem of collision will arise. In order to improve the print quality, there is a problem that the length of the deflection electrode cannot be increased due to the high deflection capability.

  The present invention has been made in view of the above problems, and provides an ink jet recording apparatus that ensures the print quality by improving the ability of ink particles, reducing the charging voltage, and shortening the flight distance. It is aimed.

  The above problem can be solved by adopting a structure in which the ink particles do not collide with the plus deflection electrode even if the deflection ability of the ink particles is improved.

  According to the present invention, it is possible to use even low-charged ink particles for printing by a deflection electrode having a high deflection capability, and provide an inkjet recording apparatus that performs high-quality printing by shortening the flight distance. can do.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating the shape of a deflection electrode in the ink jet recording apparatus according to the present embodiment, and FIG. 2 is an overview diagram illustrating the overall configuration of the ink jet recording apparatus according to the present embodiment.

  First, the configuration of this embodiment will be described with reference to FIG. 1 is an MPU (microprocessing unit) that controls the entire inkjet recording apparatus, 2 is a RAM (random access memory) that temporarily stores data in the inkjet recording apparatus, and 3 is a ROM (read) that stores programs in advance. (Only memory) 4 is a display device for displaying contents to be printed, 5 is a panel interface, and 6 is a panel for inputting character information to be printed. 7 is a print object detection circuit, 8 is a print control circuit for controlling the printing operation of the ink jet storage device, 9 is a video RAM for storing video data for charging ink particles, and 10 is a character for using the video data as a charging signal. A signal generating circuit, 11 is a nozzle that ejects ink, 12 is a charging electrode that makes ink ejected from the nozzle into particles, and charges the ink particles, 13 is a plus deflection electrode, 14 is a minus deflection electrode, and plus deflection electrode 13 The minus deflection electrode 14 forms an electric field. 15 is a gutter that collects ink that is not used for printing, 16 is a pump that supplies the ink collected from the gutter to the nozzles again, 17 is a sensor that detects the printing object, 18 is a conveyor that conveys the printing object, and 19 is A substrate to be printed, 20 is a bus line for sending data and the like.

  Next, printing will be described. First, when information such as the contents to be printed on 6 panels is input via the 5 panel interface, the MPU 1 creates video data to be charged to the ink particles according to the print information by the program stored in the ROM 3, and the bus. It is stored in the video RAM 9 via the line 20. When the printing object sensor 17 detects the printing object 19, a print start command reaches the MPU 1 through the printing object detection circuit 7. The MPU 1 sends the video data stored in the video RAM 9 to the character signal generation circuit 10 via the bus line 20. The character signal generation circuit 10 changes the received video data to a charging signal.

  The print control circuit 8 controls the timing of sending this charging signal to the charging electrode 12 via the bus line 20. The ink ejected from the nozzle 11 is converted into particles in the charging electrode 12, receives electric charges, is deflected by flying through the electric field formed by the plus deflection electrode 13 and the minus deflection electrode 14, and is then applied to the printing material 19. Flies, adheres, and is printed. At that time, the deflection is performed according to the charge amount of the ink particles. The deflection amount of ink particles having a large charge amount is large, and the deflection amount of particles having a small charge amount is small. Ink that has not been used for printing, that is, ink particles that have not been charged, is collected from the gutter 15 and supplied again to the nozzle 11 by the pump 16.

  Next, the print quality will be described with reference to FIG. In an ink jet storage device, the amount of charge applied to each ink particle is determined according to character information to form a dot matrix character. A lower charge is applied to the lowest particle located at the lowest position, and a higher charge is applied to the highest particle located at the highest position. The charged ink particles pass between the deflection electrodes and are deflected in proportion to the amount of charge. A dot matrix-like character is formed by the difference in the amount of charge applied to each particle. In order to realize high quality printing, it is necessary to reduce the influence on the print quality due to the Coulomb repulsive force generated between the ink particles. To reduce the influence of the Coulomb repulsive force, the amount of charge applied to the ink particles must be reduced. It is necessary to reduce and widen the flight trajectory between ink particles. In addition, shortening the flight distance is indispensable to reduce the influence of the air resistance on the print quality. In order to minimize the influence on the print quality, it is necessary to increase the deflection ability of the ink particles and print even a low charge ink particle at a short flight distance.

  Next, a conventional deflection electrode will be described with reference to FIGS. First, a method of a deflection electrode in which the plus deflection electrode and the minus deflection electrode shown in FIG. 3 are parallel will be described. In this method, the plus deflection electrode and the minus deflection electrode are parallel to each other, and a strong electric field is formed with a short distance between the plus deflection electrode and the minus deflection electrode. However, if the length of the plus deflection electrode and minus deflection electrode is increased to improve the deflection capability of the ink particles, the deflection of the ink particles having the largest charge amount in forming the top particle, that is, the dot matrix character. The amount becomes large and collides with the plus deflection electrode. In practice, the length of the plus deflection electrode is suppressed so that the uppermost ink particles do not collide with the plus deflection electrode. In this method, even if a strong electric field can be formed, the length of the deflection electrode is limited, so that the time during which the ink particles are deflected is shortened and the ability to deflect the ink particles is poor. In print quality, it is necessary to reduce the charge amount in order to reduce the coulomb repulsive force. However, in this method with a small deflection capacity, if the charge amount of the lowest particle is reduced, the lowest particle can jump over the gutter. It disappears and collides with gutter. Also, in order to avoid this collision, the position of the gutter must be kept away from the deflection electrode. However, even if the Coulomb repulsive force can be reduced by reducing the amount of charged charges, the flight distance becomes long and the air resistance is increased so that the print quality is not improved. On the other hand, if the printing distance is to be shortened, the position of the gutter approaches the deflection electrode, and unless the amount of charged charge is increased, the lowermost particle cannot jump over the gutter. In this case, even if the influence of the air resistance due to the shortening of the print head can be reduced, the influence on the printing due to the increase in the amount of charged charges becomes large. For this reason, the deflection capacity of the deflection electrode of this system is weak, and it is impossible to reduce the charging voltage and the flight distance. The ability to deflect ink particles is required to obtain high print quality.

  Next, the conventional deflection method shown in FIG. 4 will be described. In order to further enhance the deflection capability of the method shown in FIG. 3, a bent portion is provided in the parallel portion of the deflection electrode of FIG. 3 as shown in FIG. 4, and the ink particles are deflected for a longer time than in FIG. 3 while avoiding collision of the ink particles. It is a feature that can be done. However, in this method, the bending time is increased by providing the bending portion, but the distance between the bending portion of the plus deflection electrode and the minus deflection electrode is larger than that of the parallel portion, and the electric field strength of the bending portion is larger than that of the parallel portion. It turns out that it is remarkably weak. Therefore, in this method, even if the deflection time is long, the electric field strength at the bent portion is weak, so that the ability to deflect ink particles is not significantly changed compared to the method in FIG.

  Next, the plus deflection electrode of the present invention will be described. 1 and 5 show the deflection electrode of the present invention. First, the plus deflection electrode of FIG. 1 will be described. FIG. 1A shows the shape of the plus deflection electrode of the present invention. FIG. 1B shows an image for printing with the plus deflection electrode of the present invention. As shown in FIG. 1, the plus deflection electrode of the present invention has a slit portion that can avoid collision of ink particles, and the plus deflection electrode and the minus deflection electrode are in parallel to form a strong electric field. Also, by providing this slit part, even if the length of the parallel plus and minus deflection electrodes is increased and the deflection amount of the ink particles is increased, the top particle passes through the plus deflection electrode slit part and collides. It is possible to reach the printing object without doing so. By using this method, the amount of deflection of the lowest particle can be increased, and even if the charging voltage of the lowest particle is reduced, the gutter can be overcome, and the flight trajectory between ink particles can be widened by a strong electric field. It becomes possible, and it becomes possible to reduce the influence on the printing by the coulomb repulsive force. Further, since the deflection capability can be improved, the position of the gutter can be brought close to the deflection electrode, and the flight distance can be shortened, and the influence on the printing due to the air resistance can be reduced. As for the position of the slit provided in the plus deflection electrode, the locus of the most significant particle changes depending on the nozzle diameter, the ink ejection pressure, and the charging voltage. Therefore, the slit should be formed from the position where the most significant particle does not collide with the plus deflection electrode.

  Next, the plus deflection electrode shown in FIG. 5 will be described. FIG. 5A shows the shape of the plus deflection electrode of the present invention. FIG. 5B shows an image for printing with the plus deflection electrode of the present invention. As shown in FIG. 5, the system of the present invention has two plus deflection electrodes and the same voltage is applied. The two plus deflection electrodes and the minus deflection electrode are parallel to each other, and the plus deflection electrode and the minus deflection electrode are arranged so that ink particles can pass between the two plus deflection electrodes. A strong electric field is formed between the two. By making the deflection electrode longer, a strong electric field can be applied to the ink particles for a long time, and the ability to deflect the ink particles is improved. Even if the length of the deflection electrode is increased and the deflection amount of the ink particles is increased, the uppermost particles can pass between the plus deflection electrodes, and printing can be performed without colliding with the plus deflection electrodes. In addition, for the lowest particles, this method can be used to jump over the gutter even with a low charge, and it is possible to widen the flight trajectory between ink particles by improving the deflection capability, reducing the influence on printing due to coulomb repulsion. It becomes possible to make it. Further, the position of the gutter can be brought close to the deflection electrode, so that the flight distance can be shortened, and the influence on the printing due to the air resistance can be reduced.

  In this way, by making the structure that avoids the collision of the uppermost particles used for printing with the plus deflection electrode, it becomes possible to increase the length of the plus deflection electrode and increase the deflection capability of the ink particles. The influence on printing due to repulsion and air resistance can be reduced. As a result, the print quality can be improved.

  According to each of the embodiments described above, it is possible to provide an ink jet recording apparatus that performs high-quality printing.

Schematic which shows the shape of the plus deflection electrode provided with the slit part in this invention. An overview diagram showing the overall configuration. Schematic which shows the shape of the conventional parallel deflection electrode. Schematic which shows the shape of the plus deflection electrode which has the conventional bending part. FIG. 2 is a schematic view showing the characteristics of an ink jet recording apparatus provided with two plus deflection electrodes in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... MPU, 2 ... RAM, 3 ... ROM, 4 ... Display apparatus, 5 ... Panel interface, 6 ... Panel, 7 ... Printed object detection circuit, 8 ... Print control circuit, 9 ... Video RAM, 10 ... Character signal generation Circuit 11, Nozzle 12, Charged Electrode 13, Positive Deflection Electrode 14, Negative Deflection Electrode 15, Gutter 16, Pump 17, Print Object Detection Sensor 18, Conveyor 19, Print Object 20 ... Bus line.

Claims (4)

Pressurized ink is ejected from the nozzles, and the nozzles are vibrated at a constant period, whereby the ink is atomized at a constant period, and a charging signal synchronized with the particle formation period is applied to the charging electrode based on the character information to be printed. By applying the ink, a charge is given to the ink particles corresponding to the dots to be printed out of the ink particles, and the charged ink particles pass through the electric field formed by the plus deflection electrode and the minus deflection electrode. The ink particles corresponding to the dots that are deflected and not printed are not charged but collected in the gutter, and the printed material is moved relative to the nozzles to form characters in a dot matrix on the printed material. A recording device,
An ink jet recording apparatus having a deflection electrode provided with a slit portion that avoids collision of the ink particles with the deflection electrode according to the deflection amount of the ink particles. Pressurized ink is ejected from the nozzles, and the nozzles are vibrated at a constant period, whereby the ink is atomized at a constant period, and a charging signal synchronized with the particle formation period is applied to the charging electrode based on the character information to be printed. By applying the ink, a charge is given to the ink particles corresponding to the dots to be printed out of the ink particles, and the charged ink particles pass through the electric field formed by the plus deflection electrode and the minus deflection electrode. The ink particles corresponding to the dots that are deflected and not printed are not charged but collected in the gutter, and the printed material is moved relative to the nozzles to form characters in a dot matrix on the printed material. A recording device,
An ink jet recording apparatus in which two plus deflection electrodes to which the same voltage is applied are provided, and an interval is provided so that the deflected ink particles can pass between the two plus deflection electrodes.   2. The ink jet recording apparatus according to claim 1, wherein the length of the slit portion of the plus deflection electrode extends to the upper surface of the gutter. The ink jet recording apparatus according to claim 2, wherein two plus deflection electrodes are provided up to the upper surface of the gutter.

Images