JP2008044128A - Inkjet printer, and inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly prevent moisture condensation on the nozzle surface of an inkjet head from occurring. <P>SOLUTION: This inkjet printer 10 performs printing by an inkjet method. The inkjet printer 10 is equipped with the inkjet head 12 which jets ink droplets to a medium, and a heater 14 which heats the ink droplets which have been jetted to the medium 30. The inkjet head 12 has a conductive nozzle plate in which a nozzle for jetting the ink droplets is formed, and an induction heating section which heats the nozzle plate by electromagnetic induction heating. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inkjet printer and an inkjet head.

In an ink jet printer, a printing unit under an ink jet head may be overheated by a platen heater or the like for the purpose of drying and fixing ink. However, in this case, for example, when printing is performed at a high density, the volatile component of the warmed ink solvent may evaporate and condensation may occur on the head nozzle surface. When such dew condensation occurs, the condition of the nozzles of the ink jet head is deteriorated, and ejection disturbance occurs, which may adversely affect the printing quality of printing. In order to solve such a problem, conventionally, an ink jet printer provided with a temperature raising means for raising the temperature of the ink jet head has been proposed (for example, see Patent Document 1).
JP 2005-199434 A

  In Patent Document 1, an electric heater, a hot air circulation pipe, a hot water circulation pipe, or the like wound around the inkjet head is used as the temperature raising means. However, when such a temperature raising means is used, the nozzle plate itself cannot be directly heated, and the entire inkjet head is heated. As a result, power consumption may increase. Further, when the nozzle plate is heated to a necessary temperature, the temperature of the portion of the inkjet head that is in direct contact with the heating means may be excessively increased. Further, when the entire inkjet head is heated, the ink before jetting is heated more than necessary, and the quality may be deteriorated. Further, when a hot air circulation pipe, a hot water circulation pipe, or the like is used, the configuration of the ink jet printer becomes complicated, which may increase the cost.

  Accordingly, an object of the present invention is to provide an ink jet printer and an ink jet head that can solve the above-described problems.

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) An inkjet printer that performs printing by an inkjet method, including an inkjet head that ejects ink droplets onto a medium, and an ink heating unit that heats the ink droplets ejected onto the medium. A conductive nozzle plate on which nozzles for jetting the nozzle are formed, and an induction heating unit for heating the nozzle plate by electromagnetic induction heating. The induction heating unit includes, for example, an induction coil wound around the nozzle plate and a current supply unit that supplies a high-frequency current to the induction coil.

  If comprised in this way, the dew condensation of the nozzle surface of an inkjet head can be prevented appropriately by the heating of a nozzle plate. Also, when condensation occurs, the condensed solvent and the like can be appropriately evaporated. Therefore, it is possible to suppress ink ejection disturbance and prevent adverse effects on printing plotting quality.

  Moreover, when comprised in this way, the nozzle plate which comprises the nozzle surface of an inkjet head can be heated directly, Therefore Other parts are not heated more than necessary. Therefore, the ink before ejection is not heated more than necessary. In addition, power consumption can be suppressed. Furthermore, since the inkjet head can be heated with a simple configuration, the cost does not increase significantly.

  Note that the induction heating unit automatically starts energization to heat the nozzle plate when, for example, a preset dew condensation condition is detected. If comprised in this way, dew condensation can be prevented appropriately. The dew condensation condition is, for example, a condition such as a temperature difference between the nozzle surface temperature of the inkjet head and the platen temperature, and is set in advance based on, for example, experimental results. Further, the dew condensation condition is set based on, for example, a measurement result of a relationship between the application time of the high frequency current to the induction coil and the temperature rise of the nozzle plate.

  (Configuration 2) The nozzle plate is made of stainless steel. If comprised in this way, the nozzle plate which can be heated by electromagnetic induction heating can be formed appropriately.

  (Configuration 3) A platen that supports a medium on which ink droplets are ejected, a platen temperature measurement unit that measures the temperature of the platen heated by the ink heating unit, and a plate temperature measurement unit that measures the temperature of the nozzle plate are further provided. The induction heating unit heats the nozzle plate so that the difference between the temperature of the platen measured by the platen temperature measuring unit and the temperature of the nozzle plate measured by the plate temperature measuring unit falls within a preset range. . If comprised in this way, the temperature of a nozzle plate can be controlled appropriately. Thereby, dew condensation can be prevented appropriately.

  (Arrangement 4) An inkjet head used in an inkjet printing apparatus, having a conductive nozzle plate on which nozzles for ejecting ink droplets are formed, and an induction heating unit for heating the nozzle plate by electromagnetic induction heating With. If comprised in this way, the effect similar to the structure 1 can be acquired.

  According to the present invention, it is possible to appropriately prevent condensation on the nozzle surface of the inkjet head.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of an inkjet printer 10 according to an embodiment of the present invention. The inkjet printer 10 is a printing apparatus that performs printing on a medium 30 by an inkjet method. The inkjet head 12, the platen 16, the pinch roller 22, the feed roller 24, the heater 14, the platen temperature measuring unit 18, and the plate A temperature measurement unit 20 is provided.

  The inkjet head 12 performs printing by ejecting ink droplets onto the conveyed medium 30. The platen 16 supports a medium 30 on which ink droplets are ejected by the inkjet head 12. The pinch roller 22 and the feed roller 24 convey the medium 30 in a predetermined conveyance direction by rotating with the medium 30 supported by the platen 16 interposed therebetween.

  The heater 14 is an example of an ink heating unit, and heats ink droplets ejected onto the medium 30 to dry and fix the ink. The platen temperature measuring unit 18 is a thermometer having, for example, a thermistor embedded in the platen 16, and measures the temperature of the platen 16 heated by the heater 14 based on the resistance value of the thermistor.

  The plate temperature measuring unit 20 is, for example, a thermometer having a thermistor, and measures the temperature of the nozzle plate based on the resistance value of the thermistor. The plate temperature measuring unit 20 is disposed, for example, on the base of the ink jet head or around the ink jet head. If comprised in this way, the temperature of the nozzle surface of the inkjet head 12 can be obtained appropriately with sufficient accuracy to prevent condensation.

  FIG. 2 shows an example of the configuration of the inkjet head 12. FIG. 2A is a side view illustrating the outline of the configuration of the inkjet head 12. FIG. 2B is a bottom view of the inkjet head 12. FIG. 2C shows an example of the configuration of the nozzle plate 102 of the inkjet head 12. In this example, the inkjet head 12 includes a nozzle plate 102, a plate holding unit 104, and an induction heating unit 106. The inkjet head 12 may further include a housing that accommodates the plate holding unit 104, the induction heating unit 106, and the like.

  The nozzle plate 102 is a plate-like member made of a conductive material that can be heated by electromagnetic induction heating, and is made of, for example, stainless steel (SUS). A plurality of nozzles 206 for ejecting ink droplets are formed in the nozzle plate 102 side by side. The plate holding unit 104 holds the nozzle plate 102 on the surface facing the medium 30 in the inkjet head 12 so that the ejection direction of the nozzle 206 is directed toward the medium 30. As a result, the inkjet head 12 ejects ink droplets onto the medium 30 as indicated by the dotted arrow 304. In addition, it is preferable that the housing | casing of the plate holding | maintenance part 104 and the inkjet head 12 is formed with the raw material which is not heated by electromagnetic induction heating.

  The induction heating unit 106 is a heater that heats the nozzle plate 102 by electromagnetic induction heating, and includes an induction coil 202 and a current supply unit 204. The induction coil 202 is wound so as to surround the periphery of the nozzle plate 102, and generates an alternating magnetic field as indicated by an arrow 302 according to the high-frequency current received from the current supply unit 204.

  The current supply unit 204 is a current supply circuit that supplies a high-frequency alternating current to the induction coil 202. In this example, the induction coil 202 detects the dew condensation condition of the nozzle plate 102 based on the temperature of the platen 16 (see FIG. 1) and the nozzle plate 102 measured by the platen temperature measuring unit 18 and the plate temperature measuring unit 20. When the dew condensation condition is detected, the current supply unit 204 automatically starts energization and supplies an alternating current to the induction coil 202.

  With the above configuration, the induction heating unit 106 generates an eddy current as indicated by an arrow 306 in the nozzle plate 102 and heats the nozzle plate 102 by electromagnetic induction heating. The induction heating unit 106 heats the nozzle plate 102 so that, for example, the difference between the temperature of the platen 16 and the temperature of the nozzle plate 102 falls within a preset range. According to this example, condensation on the nozzle surface can be appropriately prevented. Also, when condensation occurs, the condensed solvent and the like can be appropriately evaporated. Therefore, it is possible to suppress ink ejection disturbance and prevent adverse effects on printing plotting quality.

  The dew condensation condition detected by the current supply unit 204 is a condition where dew condensation is expected to occur on the nozzle surface, and is set in advance by, for example, an experiment. For example, the induction heating unit 106 heats the nozzle plate 102 so that the temperature of the nozzle plate 102 is lower than the temperature of the platen 16 and the difference from the temperature of the platen 16 is within 20 ° C. The induction heating unit 106 preferably heats the nozzle plate 102 to, for example, about 40 ° C. (for example, about 30 to 50 ° C., more preferably about 35 to 45 ° C.).

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably used for an inkjet printer, for example.

1 is a diagram illustrating an example of a configuration of an inkjet printer 10 according to an embodiment of the present invention. 2 is a diagram illustrating an example of a configuration of an inkjet head 12. FIG. FIG. 2A is a side view illustrating the outline of the configuration of the inkjet head 12. FIG. 2B is a bottom view of the inkjet head 12. FIG. 2C shows an example of the configuration of the nozzle plate 102 of the inkjet head 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet printer, 12 ... Inkjet head, 14 ... Heater (ink heating part), 16 ... Platen, 18 ... Platen temperature measurement part, 20 ... Plate temperature measurement part, 22 ... Pinch roller, 24 ... Feed roller, 30 ... Media, 102 ... Nozzle plate, 104 ... Plate holding part, 106 ... Induction heating part, 202 ... Induction coil, 204 ... Current supply unit, 206 ... Nozzle

Claims (4)

An inkjet printer that performs printing by an inkjet method,
An inkjet head that ejects ink droplets onto a medium;
An ink heating unit that heats the ink droplets ejected onto the medium,
The inkjet head is
A conductive nozzle plate on which nozzles for ejecting ink droplets are formed;
An ink jet printer comprising: an induction heating unit that heats the nozzle plate by electromagnetic induction heating.   The ink jet printer according to claim 1, wherein the nozzle plate is made of stainless steel. A platen that supports the medium on which the ink droplets are ejected;
A platen temperature measuring unit for measuring the temperature of the platen heated by the ink heating unit;
A plate temperature measuring unit for measuring the temperature of the nozzle plate,
The induction heating unit includes the nozzle so that a difference between the temperature of the platen measured by the platen temperature measuring unit and the temperature of the nozzle plate measured by the plate temperature measuring unit is within a preset range. The inkjet printer according to claim 1 or 2, wherein the plate is heated. An inkjet head used in an inkjet printing apparatus,
A conductive nozzle plate on which nozzles for ejecting ink droplets are formed;
An inkjet head comprising: an induction heating unit that heats the nozzle plate by electromagnetic induction heating.

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