JP2005231283A - Cleaning method of ink-jet head for ink containing metal particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean an ink-jet head using an ink containing metal particles without damaging a nozzle with metal particles adhering on the nozzle surface. <P>SOLUTION: A nozzle washing tank 3 serving as a flushing pad for the ink-jet head 1 is provided, and the metal particles adhering on a nozzle 11 are removed by flushing the nozzle surface 10 with water. The nozzle surface is prevented from being damaged and an abnormal discharge from the nozzle can be avoided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for cleaning an inkjet head that discharges ink containing metal particles.

  Conventionally, inkjet printers have been widely used as household and industrial printers. Printers based on this ink jet method include a thermal jet method that ejects ink droplets by generating bubbles due to heat, and a piezo method that ejects ink droplets by deformation of the piezo. This printer is an on-demand system that ejects ink as necessary at a required location, and is free of noise, simple in structure, and can be miniaturized. However, since a liquid called ink is ejected, there is a drawback that nozzle clogging easily occurs, and a mechanism for preventing clogging is necessary (hereinafter referred to as a cleaning mechanism).

  For example, a conventional inkjet printer cleaning mechanism includes a wiper for scraping the dirt adhering to the periphery of the nozzle of the inkjet head downward, a mechanism for sucking bubbles or high-viscosity ink in the nozzle from the nozzle side, or a supply The configuration is a combination with a mechanism for pushing out ink from the side.

As prior art document information relating to this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 3-99857

  However, in the conventional cleaning method, when dye ink is used, when the wiper rubs around the nozzle, there is a possibility that air bubbles or dust may be pushed into the nozzle. However, since it is considered that the nozzle can be returned to a normal state by flowing ink thereafter, the ink in the ink jet head is sucked out or pushed out after the wiper operation is completed. However, in reality, dust and the like adhering to the periphery of the nozzle are firmly attached, so that the wiper rubs the nozzle surface fairly strongly. On the other hand, when ink containing metal particles was used, the metal particles attached to the nozzle surface damaged the ink jet head by the operation of the wiper, and had a problem that the water repellent treatment part on the nozzle surface was peeled off.

  The present invention is intended to solve the above-mentioned problems, and provides a cleaning method that prevents the water-repellent treatment part of the ink-jet head from being consumed and does not damage the ink-jet head in an ink-jet using ink containing metal particles. It is intended.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided an ink jet head cleaning method in which a nozzle surface of an ink jet head that ejects ink from a nozzle is scraped off by a wiper. The operation is performed. As an action, the nozzle surface after priming is attached to the liquid to remove the metal particles attached to the nozzle surface to clean the nozzle surface, and thereafter, the water droplets attached to the nozzle surface are wiped off with a wiper to perform cleaning. For this reason, the effect which can prevent the damage to the inkjet head by a wiper operation | movement is acquired.

  According to the second aspect of the present invention, in the above-described cleaning method, not only the nozzle surface is attached to the cleaning liquid, but also the cleaning effect can be improved by the liquid discharged toward the nozzle surface.

  At this time, by making an angle with respect to the nozzle surface, it is possible to prevent the liquid from entering the nozzle as much as possible.

  According to a third aspect of the present invention, in the above cleaning method, the cleaning tank has a two-tank structure including a cleaning liquid tank and an ink discharge tank, thereby saving space and discharging excess ink. This is used for both cleaning and cleaning, and after discharging the extra ink, a new liquid is supplied from below to discharge the extra ink, and the next cleaning is performed with a clean liquid.

  In the invention according to claim 4 of the present invention, when the ink component and the liquid to be cleaned are close to each other in the cleaning method described above, the cleaning liquid is mixed into the ink in the head, and thus the ink is discharged for a while after cleaning. The mixed liquid is excluded.

  According to a fifth aspect of the present invention, in the above cleaning method, when the cleaning liquid is discharged to clean the nozzle surface, the cleaning liquid enters the nozzle so that the cleaning liquid does not enter the nozzle with the force of discharge. In order to prevent the ink from entering, pressure is applied to the ink in advance to prevent the ink from entering the nozzle due to the momentum of ejection.

  According to the inkjet head cleaning method of removing dirt from the nozzle surface of the inkjet head in the present invention, the nozzle discharge surface is not damaged even if the nozzle surface is scraped off with a wiper, and the nozzle discharge abnormality is prevented from occurring. Have.

  The invention according to the first to fifth aspects of the present invention will be described below with reference to the first embodiment.

  FIG. 1 is a schematic diagram of a cleaning method according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of the inkjet head, and FIG. 3 is a schematic diagram showing a configuration of liquid cleaning.

  In FIG. 1, reference numeral 1 denotes an ink jet head, which is a pressure type ink jet head, and has a number of nozzles 11 and an ink chamber 12 connected to the nozzle surface 10. Ink is supplied from an ink tank 8 described later. Reference numeral 2 denotes an ink collection tank, which is a tank for collecting dirty liquid after washing and excess ink. Reference numeral 3 denotes a nozzle cleaning tank that cleans the nozzle surface 10 of the inkjet head 1 and contains a liquid that cleans the nozzle surface 10. A wiper 4 wipes the nozzle surface 10 after cleaning. In FIG. 2, reference numeral 10 denotes a nozzle surface of the ink jet head 1, and this surface is usually provided with a water repellent film. Reference numeral 11 denotes a nozzle of the inkjet head 1, and ink is ejected through the nozzle. An ink chamber 12 is supplied with ink from an ink tank 8 described later. In FIG. 3, reference numeral 5 denotes a tube for supplying ink from an ink tank 8 described later to the inkjet head. Reference numeral 6 denotes a pump for supplying ink to the inkjet head 1. Reference numeral 7 denotes a circulation valve, which is closed to pressurize ink by the above-described pump 6 to prime the inkjet head 1. Reference numeral 8 denotes an ink tank which stores ink guided to the inkjet head 1 using the pump 6 described above. Reference numeral 9 denotes a front / rear cylinder, which wipes the nozzle surface 10 by moving the wiper 4.

  Next, an operation according to an embodiment of the present invention will be described. During normal printing, the ink chamber 12 of the ink jet head 1 forms a meniscus in the ink jet head nozzle portion due to negative pressure, and the ink jet head 1 faces the ink chamber 12 by an ink jet head drive signal from the control unit (not shown). The piezoelectric element is driven to eject ink. The cleaning works as follows.

  (1) Upon receiving the cleaning command, the control unit raises the inkjet head 1 to the cleaning position by NC.

  (2) When the inkjet head 1 has moved to the cleaning position, the nozzle cleaning tank 3 is moved laterally directly below the inkjet head 1 by the front and rear cylinders 9.

  (3) The pump 6 is stopped and the ink-jet head 1 is moved up and down to the water-washing position with the ink circulation stopped to perform water-washing.

  (4) When the inkjet head 1 is washed with water, the pump 6 is driven by raising the cleaning position to drive the circulation valve 7 and applying the ink pressure to the inkjet head 1 to remove the dirt and air in the nozzle. Priming is effective for spitting out.

  (5) After the priming is completed, the circulation cylinder is released and the pressure is released to the inkjet head 1. Since the ink after priming is accumulated in the nozzle cleaning tank 3, sewage is poured into the ink recovery tank 2 by washing with water. Then, the water in the nozzle cleaning tank 3 is cleaned.

  (6) After cleaning the water in the nozzle cleaning tank 3, the inkjet head 1 is moved up and down to the water cleaning position to perform water cleaning. At this time, the metal powder and dust attached to the nozzle surface 10 are removed.

  (7) When the metal powder and dust attached to the nozzle surface 10 are removed, the inkjet head 1 moves up to the cleaning position. After the ink-jet head 1 completes the upward movement to the cleaning position, the front and rear cylinders 9 move forward, and the wiper 4 rubs the ink-jet head 1 and drops excess water droplets on the ink-jet head 1.

  As described above, according to the ink jet head cleaning method for removing dirt from the nozzle surface 10 of the ink jet head 1 according to the present invention, even if the nozzle surface 10 is scraped off with the wiper 4, the nozzle surface 10 is not damaged, and the nozzle ejection abnormality occurs. It has the effect of preventing the occurrence.

  The inkjet head cleaning method of the present invention has the effect of preventing the occurrence of nozzle ejection abnormalities without damaging the nozzle surface even if the nozzle surface is scraped off with a wiper, and ejecting ink containing metal particles. This is useful for cleaning an inkjet head.

Schematic diagram of the cleaning method in the present invention Enlarged view of the inkjet head of the present invention Schematic diagram showing the configuration of the liquid cleaning of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Ink collection tank 3 Nozzle washing tank 4 Wiper 5 Tube 6 Pump 7 Circulation valve 8 Ink tank 9 Front and rear cylinders

Claims (5)

Ink-jet head cleaning for cleaning ink remaining on nozzle surface after priming operation in a cleaning method in which the nozzle of the inkjet head that discharges ink containing metal particles is wiped off with a wiper Method. 2. The method for cleaning an ink jet head of ink containing metal particles according to claim 1, wherein the cleaning of the nozzle surface is performed by discharging a cleaning liquid toward the nozzle surface to clean the nozzle surface. 2. The metal particle according to claim 1, wherein the cleaning tank has a two-tank structure that serves both as a cleaning liquid tank and an ink discharge tank. A method for cleaning an ink jet head of ink containing the ink. 2. The method for cleaning an ink jet head of ink containing metal particles according to claim 1, wherein the cleaning liquid in the nozzle of the ink jet head is discharged for a while after the cleaning so that the cleaning liquid is not mixed with the ink component, and the mixed liquid is removed. 2. The method for cleaning an ink jet head of ink containing metal particles according to claim 1, wherein, in the cleaning of the nozzle of the ink jet head, the liquid is prevented from entering the nozzle by pressurizing the ink in advance.

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