JP2007313806A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein an organic solvent for ink is volatilized into the outside air while an inkjet recorder is stopped, and a resin component included in the ink is dried and fixed in a recovery pump, since a route from a gutter opening to the recovery pump is communicated with the outside air, and as a result, in the next recorder starting, the pump performance can not be provided. <P>SOLUTION: The inkjet recorder is provided with a closing mechanism which prevents the ink recovery pump 15 from communicating with the outside air, in the route between a gutter 13 in the print head 610 and the ink recovery pump. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that draws a print or a pattern on a printing material transported on a production line by ejected ink particles.

  Generally, a continuous ink jet recording apparatus is provided with an ink container for storing ink in a main body, and the ink in the ink container is supplied to a print head by a supply pump. The ink supplied to the print head is continuously ejected from the nozzles and converted into particles. Among the ink particles, the ink particles used for printing are charged and deflected to fly to a desired position, and the ink particles not used for printing are not charged and deflected and collected by a gutter and collected. Return to ink container by pump. As described above, ink is always circulated during operation of the apparatus. The ink used is a solution of dye and resin dissolved in a solvent, and requires quick drying so that the printed surface will not be rubbed due to material handling after printing, etc. In addition, a highly volatile organic solvent is frequently used as the solvent. Therefore, when stopping the device, if the ink remains in the nozzle, the ink will dry and adhere and clog the fine holes in the nozzle. Therefore, after the ink supply is stopped, the ink solvent is ejected instead. It is a mechanism that automatically cleans fine holes. As for the inside of the collection line, the collection pump is operated even after automatic cleaning of the nozzles, and the ink in the path is returned to the ink container and stopped.

  As a conventional ink jet recording apparatus, there is known an ink jet recording apparatus in which a diaphragm pump is installed in a print head as a recovery pump. In this configuration, the flow path between the gutter and the recovery pump is shortened and the pressure loss is reduced, so that the ink recovery from the gutter is improved. However, the recovery pump is connected to the outside air through the flow path communicating with the gutter. It has become.

JP 2000-6438 A

  As described in the background art, when the apparatus is stopped, the recovery pump is operated to return the ink in the path to the ink container even after the ejection of the ink and the solvent from the nozzle is completed. The inside of the interior can be prevented except for the wall surface.

  However, since the recovery pump itself has a complicated structure, the residual ink inside cannot be eliminated. In particular, it is difficult to completely remove the ink adhering to the seal surface of the reverse valve, which is essential for the diaphragm pump. On the other hand, since the path from the gutter opening to the recovery pump communicates with the outside air, the organic solvent that is the solvent of the ink volatilizes to the outside air during the stoppage, and the resin component contained in the ink is dried and fixed inside the recovery pump. To do. If the recovery pump is fixed, there will be a problem that the pump performance cannot be obtained and the recovery function cannot be satisfied satisfactorily at the next startup of the apparatus.

  The problem can be solved by providing a mechanism for closing a flow path between the gutter in the print head and the path of the ink recovery pump.

  By providing a closing mechanism, the recovery pump is shut off from the outside air and the solvent of the ink can be prevented from volatilizing. Therefore, the ink remaining in the recovery pump does not adhere while the apparatus is stopped, and the function of the recovery pump is not impaired. . Therefore, an ink jet recording apparatus capable of stable operation can be provided.

  Examples of the present invention will be described below.

  FIG. 2 shows the configuration of an ink jet recording apparatus according to an embodiment of the present invention.

  The ink jet recording apparatus includes a main body 600 containing a control system and a circulation system, a print head 610 having a nozzle for ejecting ink and creating ink particles, and a cable 620 connecting the circulation system and the control system of the main body 600 and the print head 610. It is configured with.

  The main body 600 is provided with a liquid crystal panel 630 on which a user can input print contents and print specifications, and display control contents and device operating conditions, and an operation control unit of a control system.

  The print head 610 is covered with a stainless steel cover, and a printing unit for creating ink particles and controlling the flying of the ink particles is housed in the print head 610. The hole 615 provided on the bottom surface of the cover is for the passage of ink particles.

  FIG. 1 shows an ink circulation path of an ink jet recording apparatus according to the present invention.

  The main body 600 has an ink container 2, an ink supply pump 3, a filter 4, and an ink pressure regulating valve 5 as a path for supplying the ink 1 to the nozzle 10, and is connected in order.

  Further, a cleaning liquid container 7 and a cleaning liquid supply pump 8 are provided as a path for supplying the cleaning liquid 6 to the nozzle 10 and are connected in order as in the ink supply path.

  Both paths are connected to the three-way switching electromagnetic valve 9 of the print head 610 through the cable 620. The three-way switching electromagnetic valve 9 functions to switch the supply liquid to the nozzle 10 to either the ink 1 or the cleaning liquid 6. During the operation of the apparatus, the three-way switching electromagnetic valve 9 is excited and the supply path side is opened, and the ink 1 is supplied to the nozzle 10 to become ejected ink particles 11. The ink particles 11 are selectively charged by the subsequent charging electrode 12, and the charged ink particles 11 are further subjected to a deflection force in the electrolysis formed by the subsequent deflection electrode 16, jumping over the gutter 13 and reaching the printed matter 17. . On the other hand, the ink particles 11 that have not been charged go straight, are collected by the gutter 13, returned to the ink container 2 of the main body 600 by the ink recovery pump 15, and ejected again.

  The difference of the present invention from the prior art is that a recovery electromagnetic valve 14 that has not been conventionally arranged is disposed between the gutter 13 and the ink recovery pump 15.

  In the continuous type ink jet recording apparatus, the ink 1 is always ejected and collected and re-ejected during the operation of the apparatus, so that the ink 1 is not dried and fixed at the nozzle 10 outlet. However, when the apparatus is stopped, no ink is ejected. If the apparatus is simply stopped, the residual ink 1 in the nozzle is dried and fixed, and the nozzle outlet is blocked.

  In particular, the ink for continuous ink jet recording devices is often made of non-absorptive materials such as metal and glass. The organic solvent is highly volatile as a solvent for dyes and resins so that it dries quickly after printing. Because it is used, it will dry and stick in a short time.

  Therefore, when the apparatus is stopped, the excitation of the three-way switching solenoid valve 9 is stopped, the liquid supplied to the nozzle 10 is switched to the cleaning liquid 6, and the ink is removed from the nozzle 10 by flowing the cleaning liquid, so that the ink 1 is dried and fixed, and the nozzle outlet It is the structure which prevents blocking up.

  Although this structure can prevent the ink 1 supply system from being dried and fixed, the problem is the ink recovery system.

  When the ink recovery pump 15 is simply arranged directly behind the gutter 13 in the print head 610 as in the prior art (the structure without the recovery electromagnetic valve 14), the ink recovery pump 15 is connected to the outside air through the opening of the gutter 13. Because of the communication, the solvent component of the residual ink inside the ink recovery pump 15 may volatilize and dry and adhere, and the pump performance may be impaired.

  This problem will be described in detail with reference to FIGS.

  As the ink recovery pump installed in the print head 610, suction in a gas-liquid mixed state is required, so a diaphragm pump, a bellows pump, or the like is applied, but any pump requires a reverse support valve for switching between suction and discharge And it has a built-in configuration. 3 and 4 show examples of the structure of the diaphragm pump. FIG. 3 shows a state during suction and FIG. 4 shows a state during discharge.

  In both figures, a diaphragm 23 is held by a lower housing 22 and an upper housing 21 in which a suction tube 27, a discharge tube 28, a suction reverse support valve 25, and a discharge reverse support valve 26 are incorporated, and the central portion of the diaphragm 23 is connected to a piston 24. It is fixed and held by adhesion or mechanical fastening.

  The suction reverse support valve 25 and the discharge reverse support valve 26 are made of rubber or the like, and have a structure in which the ink passage port 22b of the lower housing 22 is closed only by its own elastic force.

  In this structure, the volume of the chamber 22a of the lower housing 22 is changed by the vertical movement of the piston 24, and pressure reduction / pressurization is repeated. When the piston rises and is in a depressurized state (the state shown in FIG. 3), the outer periphery of the suction reverse support valve 25 is deformed and sucks ink into the chamber 22a as indicated by an arrow. On the contrary, when the piston descends and is in a pressurized state (the state shown in FIG. 4), the discharge reverse support valve 26 is deformed, and ink is sent from the chamber 22a to the discharge tube 28 as indicated by the arrow. The above operation is repeated at high speed to collect ink that enters the gutter 13 and return it to the ink container 2.

  As an actual operation when the ink jet recording apparatus is stopped, in addition to cleaning the nozzle as described above, the ejection of the cleaning liquid is stopped so that the opening of the gutter 13 is not blocked by the dry fixing of the residual ink in the recovery path. After that, the ink recovery pump 15 is operated for a certain period of time so that the ink in the recovery path is returned to the ink container 2.

  However, as shown in FIGS. 3 and 4, the ink recovery pump 15 has a complicated shape, and ink is applied to the corners of the chamber 22 a, the suction reverse support valve 25, the contact portions 25 a and 26 a between the discharge reverse support valve 26 and the lower housing 22. Therefore, when the apparatus is stopped, the suction reverse support valve 25 and the discharge reverse support valve 26 are not deformed in accordance with the pressure reduction / pressurization, and the pump performance cannot be obtained.

  In order to solve this problem, it is effective to prevent communication with the outside air so that the solvent component of the residual ink in the ink recovery pump 15 does not volatilize, and a flow path between the gutter 13 and the ink recovery pump 15 is provided. This can be solved by arranging a closing mechanism that closes.

  In FIG. 1, the recovery electromagnetic valve 14 is arranged as a closing mechanism. However, since it is sufficient if the flow path can be closed during the stop period, it is not necessary to stick to opening / closing by solenoid driving, and a manual valve may be used.

  A structural example of an actual closing mechanism will be described with reference to FIGS. 5, 6, 7, and 8. However, the structure of the closing mechanism is not limited to the present embodiment.

  5 and 6 are examples in which a flow path is formed by a structure and a closing mechanism is provided. FIG. 5 shows a closed state, and FIG. 6 shows an open state.

  In both figures, the lower body 31 is formed with an introduction flow path 31a, a discharge flow path 31b, and a valve seat 31c, and an introduction tube 35 and a discharge tube 36 are connected thereto. The lower body 31 and the upper body 32 sandwich and hold the seal member 33, and the central portion of the seal member 33 is fixed and held to the plunger 34 by adhesion or mechanical fastening. The plunge is not shown. It is a mechanism that moves up and down by solenoid on / off. In this structure, when the plunger 34 is lowered (the state shown in FIG. 5), the seal member 33 is pressed against the valve seat 31c of the lower body 31, the space between the introduction passage 31a and the discharge passage 31b is closed, and the plunger 34 is raised. In this state (the state of FIG. 6), the introduction channel 31a and the discharge channel 31b communicate with each other in the direction of the arrow. When the apparatus is stopped, the solenoid is turned off and the state shown in FIG. 5 is obtained. When the apparatus is stopped, ink remains on the seal member 33 and the valve seat 31c, and after that, the seal member is surely peeled off from the valve seat 31c by the movement of the plunger 34 when the apparatus is started next time. And the flow path is opened.

  7 and 8 show another example, in which the flow path is directly opened and closed. FIG. 7 shows a closed state, and FIG. 8 shows an open state.

  A part of the flow path is formed of an elastic tube 41 such as rubber, and an introduction tube 45 and a discharge tube 46 are connected to both ends. A part of the elastic tube 41 is fixedly held to the plunger 43 by adhesion or mechanical fastening. The plunger guide 42 guides the vertical movement of the plunger 43 and has an adhesive surface 42 a on the side opposite to the plunger of the elastic tube 41. In this structure, when the plunger 43 is lowered (FIG. 7), the elastic tube 41 is crushed and the flow path is closed. When the plunger 43 is raised (FIG. 8), the plunger 34 is raised, and one side of the tube outer wall is fixed to the plunger 42 and the other is fixed to the adhesive surface 42a. Open.

  Also in this case, the elastic tube 41 is reliably deformed by the vertical movement of the plunger 43, so that even if the residual ink in the closing portion 41a is dried and fixed, it can be reliably peeled off and the flow path can be opened and closed.

  In both cases, the plunger can be moved up and down by a solenoid or manually.

  By disposing the closing mechanism in the above example between the gutter 13 and the ink recovery pump 15, the ink recovery pump 15 does not communicate with the outside air during the stop, so that the residual ink is not dried and fixed.

  Therefore, the performance of the ink recovery pump 15 can be obtained at the time of restart, and the apparatus can be stably operated.

1 is a simplified diagram of an ink circulation path of an ink jet recording apparatus according to an embodiment of the present invention. 1 is an external view of an ink jet recording apparatus according to an embodiment of the present invention. Simplified view of ink recovery pump (suction state). Simplified view of ink recovery pump (discharge state). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified diagram (1) of a flow path closing mechanism according to an embodiment of the present invention. The simplification figure (2) of the flow-path closing mechanism concerning the Example of this invention. The simplification figure (3) of the flow-path closing mechanism concerning the Example of this invention. The simplification figure (4) of the flow-path closing mechanism concerning the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ink container, 2 ... Ink, 3 ... Ink supply pump, 4 ... Filter, 5 ... Ink pressure regulating valve, 6 ... Cleaning liquid, 7 ... Cleaning liquid container, 8 ... Cleaning liquid supply pump, 9 ... Three-way switching voltage valve, 10 ... Nozzle , 11 ... Ink particles, 12 ... Charging voltage, 13 ... Gutter, 14 ... Recovery solenoid valve, 15 ... Ink recovery pump, 16 ... Deflection electrode, 17 ... Printed matter, 21 ... Upper housing, 22 ... Lower housing, 23 ... Diaphragm 24 ... Piston, 25 ... Suction reverse support valve, 26 ... Discharge reverse support valve, 27 ... Suction tube, 28 ... Discharge, 22a ... Cambo, 22b ... Ink passage rod, 25a, 26a ... Contact part, 31 ... Main body 32 ... Main body, 33 ... Seal member, 34 ... Plunger, 35 ... Introducing tube, 36 ... Discharging tube, 31a ... Introducing passage, 31b ... Discharging passage, 31c ... Valve seat, 41 ... Elastic chew 42 ... plunger guide, 43 ... plunger, 45 ... introducing tube, 46 ... discharge tube, 42a ... adhesive surface, 600 ... main body, 610 ... print head, 615 ... hole, 620 ... cable, 630 ... liquid crystal panel.

Claims (3)

A main body provided with an ink container for storing ink, an ink supply pump for supplying the ink, and an operation control unit;
A nozzle that ejects ink supplied from the main body as ink particles, a charging electrode that charges the ink particles, a deflection electrode that deflects the charged ink particles, and a gutter that collects ink particles that have not been used for printing. A print head, and
An ink supply path for supplying the ink from the main body to the print head, an ink recovery path for returning ink particles collected by the gutter to the ink container, and various signal lines connecting the operation control unit and the print head. In an ink jet recording apparatus comprising a cable that is wound, and having an ink recovery pump for sucking ink particles collected from the gutter in the print head,
An ink jet recording apparatus comprising: a closing mechanism for preventing the ink recovery pump from communicating with the atmosphere in an ink path between the gutter and the ink recovery pump. The inkjet recording apparatus according to claim 1, wherein
The ink-jet recording apparatus according to claim 1, wherein the closing mechanism uses a manual valve or an electromagnetic valve that can directly open and close the closing portion. The inkjet recording apparatus according to claim 1 or 2,
An ink jet recording apparatus, wherein the closing portion also serves as an ink flow path.

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