JP2008143081A - Pressure buffer and inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the buffer performance of a pressure buffer, to simplify a manufacturing process, and to stabilize quality. <P>SOLUTION: A pressure buffer continuously connected as a part of an ink channel of an inkjet head comprises: a pressure buffer body 201 having a recess formed on at least one surface; a pressure buffer membrane 20 with elasticity which is fixed to the edge of the pressure buffer body in such a manner as to cover the inside of the pressure buffer body in a sealed state, and an elastic member 204 which is arranged in such a manner that one end abuts on the inside bottom surface of the pressure buffer body 201 and that the other end abuts on the pressure buffer membrane 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure buffer used for an ink jet head applied to a printer, a fax machine or the like.

  A serial printing type ink jet recording apparatus as shown in FIG. 1 is reciprocated in a main scanning direction which is mounted on a carriage 2 and transported at least in a sub scanning direction (not shown) and is mounted on a carriage 2 and orthogonal to the sub scanning direction. The moving ink jet head 1 is provided, and an image is formed by ejecting ink droplets from the ink jet head 1 at a desired timing and landing on the surface of a recording medium based on print data.

  Particularly, in a large-sized ink jet recording apparatus that forms a large image on a relatively large recording medium, a large capacity main tank 5 is provided on the ink jet recording apparatus main body side as an ink supply source in order to consume a large amount of ink. Furthermore, a configuration is adopted in which a sub tank 9 is provided in the middle of an ink supply tube a7 connecting the main tank 5 and the inkjet head 1 to supply ink to the inkjet head 1.

  The main tank 5 serving as an ink supply source has a structure that can be attached to a main tank storage portion 6 provided at a predetermined position in the apparatus. The main tank 5 is equipped with an air shielding container 5a capable of storing ink sufficiently deaerated during the ink injection process. In this example, the air shielding container 5a is a gusset type formed of a flexible material. This is a bag-shaped ink pack, and a sufficient quality gas barrier property is secured by providing an aluminum foil layer on one layer of a flexible material.

  In addition, a rubber septum (not shown) is provided at the coupling end of the air shielding container 5a with the ink supply path, and the air shielding container is formed by the insertion coupling of the needle 6a provided in the main body main tank storage section 6. The main tank storage unit 6 is configured to be detachable without reducing the deaeration rate of the deaeration ink stored in 5a. The needle 6a provided in the main tank housing portion 6 is connected to an ink supply tube a7 made of a flexible tube, and one end of the ink supply tube a7 is extended from the ink inlet of the sub tank 9 by a flexible tube. It is connected to a coupling member (not shown) provided at the terminal end. A suction pump 8 for pumping the deaerated ink stored in the main tank 5 to the sub tank 9 is disposed in the middle of the ink supply tube a7.

  Further, a service station for cleaning the inkjet head 1 and the like is provided outside the non-printing area in the main scanning direction. The capping unit 3 for sealing the nozzle formation surface of the inkjet head 1 is disposed in this service station. Has been. A negative pressure can be applied to the capping unit 3 by the suction pump 4, and an air release valve is provided so that the negative pressure state of the capping unit 3 can be opened. By configuring in this way, it is possible to remove dust accumulated in the inkjet head 1 (cleaning operation) and to perform an initial ink filling operation into the apparatus.

When performing image formation, the carriage 2 reciprocates, so that a pressure wave is generated in the ink supply tube b10 due to the inertia of the ink in the ink supply tube b10 from the sub tank 9 to the inkjet head 1. The pressure wave of ink reaches the inkjet head 1 and affects ink ejection. Therefore, as shown in FIG. 2, by providing the inkjet head 1 with the pressure buffer 20, the pressure wave is reduced and the influence on the ink ejection is reduced. The pressure buffer 20 is configured by attaching a pressure buffer film made of a flexible plastic film to the pressure buffer body using thermal welding or ultrasonic welding (for example, Patent Document 1). The pressure buffer 20 reduces the pressure wave caused by changing the volume of the ink reservoir formed by the pressure buffer body and the pressure buffer film.
JP 2005-22229 A

  However, since the pressure buffer film is a plastic film, the volume of the ink reservoir cannot be effectively changed due to poor deformability. Also, when manufacturing the pressure buffer, when welding the pressure buffer film to the pressure buffer body, heat welding or ultrasonic welding is used, so the pressure buffer film or pressure buffer body may be deformed by welding. There is.

  An object of the present invention is to provide a pressure buffer that effectively changes the volume of an ink reservoir and an ink jet head using the pressure buffer.

  The pressure shock absorber of the present invention is a pressure shock absorber connected as a part of the ink flow path of the ink jet head, wherein the pressure shock absorber main body having a recess on at least one surface and the inside of the pressure shock absorber main body are sealed A pressure buffer film which is fixed to an edge of the pressure buffer body so as to cover and has elasticity, an ink storage part formed by joining the pressure buffer body and the pressure buffer film, and the pressure buffer body And an elastic member arranged so that one end abuts against the inner bottom surface and the other end abuts against the pressure buffer film.

  The pressure buffer film is made of a rubber material.

  The rubber material is made of ethylene propylene rubber or nitrile rubber.

  Furthermore, the pressure buffer film of the present invention can be formed in a bellows shape.

  The pressure buffer includes a pressure buffer film holding member having an area larger than a contact area between the elastic member and the pressure buffer film between the elastic member of the pressure buffer and the pressure buffer film. It is trivial.

  The pressure buffer film is fixed by a pressing member that presses the pressure buffer body.

  Further, the pressure buffer covers the pressure buffer film so as to be sandwiched between the pressure buffer body and a pressure regulation that forms a volume space similar to the ink reservoir between the pressure buffer film and the pressure buffer film. The pressure buffer film is fixed by a plate.

  In addition, an ink jet head according to the present invention includes the vitality buffer.

  By adopting the above structure, the deformability of the pressure buffer film is improved, and the volume of the ink reservoir can be greatly changed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram schematically showing a basic configuration relating to ink supply of the ink jet recording apparatus of the present invention. In FIG. 1, a carriage 2 is mounted with an inkjet head 1 and is supported on a recording medium (not shown) disposed below the inkjet head 1 so as to be able to reciprocate in a main scanning direction perpendicular to the conveyance direction of the recording medium. .

  The sub tank 9 is provided with a flexible ink bag, and an ink supply tube made of a flexible tube is connected to a connecting member provided at a terminal portion extended from the ink outlet of the sub tank 9 by a flexible tube. One end of b10 is connected, and the other end of the ink supply tube b10 is connected to the inkjet head 1 via the pressure buffer 20 on the carriage 2. In this embodiment, the sub-tank 9 is a sub-tank holder (not shown) that is easily disposed at a predetermined position of the main body by attaching and detaching the coupling member, the ink supply tube a7, and the ink supply tube b10 provided in the vicinity of the ink outlet. ), The sub-tank 9 can be mounted and removed.

  The main tank 5 serving as an ink supply source has a structure in which an ink reservoir is open to the atmosphere and new ink can be added when the amount of ink decreases. The main tank 5 communicates with an ink supply tube a7 made of a flexible tube, and one end of the ink supply tube a7 is provided at a terminal portion extended from the ink inlet of the sub tank 9 with a flexible tube. Connected to a coupling member (not shown). A suction pump 8 for pumping ink stored in the main tank 5 to the sub tank 9 is disposed in the middle of the ink supply tube a7.

  FIG. 2 is a configuration diagram of the inkjet head in the present embodiment. As described above, the ink jet head 1 is connected to the ink supply tube b10 and the pressure buffer 20 shown in FIG. When performing image formation, the carriage 2 reciprocates and ejects ink droplets at a designated timing. At this time, a pressure wave is generated in the ink supply tube b10 due to the inertia of the ink in the ink supply tube b10 extending from the sub tank 9 to the inkjet head 1. In addition, pressure drop occurs in the ink in the inkjet head 1 due to the ejection of ink droplets. The pressure buffer 20 reduces the pressure fluctuation wave in the ink supply tube b10 due to the movement of the carriage and the sudden pressure drop due to the ink ejection, and mitigates the influence on the ink ejection caused by the pressure fluctuation.

  FIG. 3 is a cross-sectional view schematically showing the pressure buffer 20 according to the first embodiment of the present invention. The cross section is the cross section AA shown in FIG. Moreover, the pressure buffer 20 of a prior art example is typically shown in FIG. The pressure buffer 20 shown in FIG. 9 includes a pressure buffer body 201 having a recess on at least one surface, a flexible film 208, and an ink reservoir 203 formed by the flexible film 208 and the pressure buffer body 201. Have. In contrast, the pressure buffer 20 shown in FIG. 3 includes a pressure buffer body 201 having a recess on at least one surface, a pressure buffer film 202 made of a rubber material having elasticity, and the pressure buffer film 202 and the pressure buffer. It has an ink reservoir 203 formed by the container body 201. The pressure buffering performance of the pressure buffer 20 depends on the volume change amount of the ink storage unit 203, and the buffer capacity is higher when the volume change amount is larger. That is, by giving the pressure buffer film 202 elasticity, the volume change amount can be improved and the pressure buffering capacity can be increased.

  The material of the pressure buffer film 202 in the present embodiment is changed according to the ink type, for example, ethylene propylene rubber when the ink used is a solvent ink, and nitrile rubber when the ink is used. Can do.

  FIG. 4 is a sectional view schematically showing a pressure buffer 20 according to the second embodiment of the present invention. In FIG. 4, in addition to the configuration of FIG. 3, an elastic member 204 is provided between the pressure buffer film 202 and the pressure buffer body 201. In the ink jet recording apparatus, the ink jet head 1 is generally disposed above the main tank 5. Thereby, a negative pressure due to a water head difference is applied to the ink jet head 1 and the ink leakage is prevented. In addition, by providing the elastic member 204, it is possible to mitigate a decrease in the volume of the ink storage unit 203 due to the negative pressure due to the above-described water head difference.

  FIG. 5 is a cross-sectional view schematically showing a pressure buffer 20 according to the third embodiment of the present invention. In FIG. 5, in addition to the configuration of FIG. 4, the shape of the pressure buffer film 202 is easily deformed. By changing the shape of the pressure buffer film 202, it is possible to further increase the volume change amount of the ink storage unit 203 and to secure the volume change amount even with a rubber material having poor stretchability. Thereby, the range of selection of the rubber material is expanded, and it becomes possible to cope with various ink types.

  FIG. 6 is a cross-sectional view schematically showing a pressure buffer 20 according to the fourth embodiment of the present invention. In FIG. 6, in addition to the configuration of FIG. 4, a pressure buffer film holding member 205 is provided between the elastic member 204 and the pressure buffer film 202. When the pressure buffer film 202 is supported by the elastic member 204, the pressure buffer film holding member 205 is provided to increase the contact area and prevent a partial pressing force from being applied. Thereby, damage to the pressure buffer film 202 can be prevented.

  FIG. 7 is a cross-sectional view schematically showing a pressure buffer 20 according to the fifth embodiment of the present invention. 7 includes a pressing member 206 that presses the pressure buffer film 202 against the pressure buffer body 201 in addition to the configuration of FIG. In the pressure buffer 20 of the conventional example, the pressure buffer main body 201 and the pressure buffer film 202 are made of the same material, and are joined without a gap by thermal welding, ultrasonic welding, or adhesion. In the conventional example, the bonding is such that it cannot be disassembled, and when the pressure buffer film 202 is damaged, there is nothing but to discard. Moreover, when joining by heat welding, the pressure buffer main body 201 was heated and warp was generated, resulting in deterioration of component dimensional accuracy. In this embodiment, by using a rubber material for the pressure buffer film 202, the pressure buffer body 202 and the pressure buffer film 202 are brought into close contact with each other by pressing the pressure buffer film 202 itself with the pressing member 206, and bonded without a gap. I can do it. As a pressing method, coupling with a screw or rivet, fixing with a clip, or the like is possible. In addition, since no bonding or welding is used for joining, disassembly is easy, and even when the pressure buffer film 202 is damaged, it can be replaced alone, so that parts can be reused. In addition, since there is no restriction that the material can be welded, the material selection range of the pressure shock absorber main body 201 is widened.

  FIG. 8 is a cross-sectional view schematically showing a pressure shock absorber 20 according to Embodiment 6 of the present invention. In FIG. 8, in addition to the configuration of FIG. 4, a pressure regulating plate 207 is provided outside the pressure buffer film 202. The pressure restricting plate 207 has a rigidity equal to or higher than that of the pressure buffer main body 201, and the pressure buffer film is provided on the side opposite to the ink reservoir 203 as viewed from the pressure buffer film 202 even when a positive pressure assumed at the time of printing is applied. A space having such a size that 202 does not come into contact with the pressure regulating plate 207 is formed. The pressure regulating plate 207 is a member formed by, for example, plastic injection molding or sheet metal drawing. Similar to the pressing member 206, the pressure regulating plate 207 is pressed and fixed with screws, rivets, clips, etc., and can also have the function of the pressing member 206. In this embodiment, by providing the pressure regulating plate 207, the pressure buffering film 202 is prevented from bulging more than necessary due to the positive pressure and causing damage or rupture. Therefore, not only suction filling when ink is filled into the inkjet head 1, but also pressure filling that applies high pressure to the ink is possible.

  Although the form of this figure demonstrated the structure containing the one inkjet head 1 corresponding to 1 color of printing in a serial type inkjet recording device, it is a flat bed type which moves a head fixed line type printer or a recording material. The same effect can be obtained also in the printer, and other embodiments are not excluded as long as they meet the gist of the present embodiment.

1 is a diagram schematically illustrating a basic configuration of an inkjet head according to an embodiment of the present invention. It is a block diagram of the inkjet head which concerns on embodiment of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 1 of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 2 of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 3 of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 4 of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 5 of this invention. It is sectional drawing which showed typically the pressure buffer which concerns on Example 6 of this invention. It is sectional drawing which showed the pressure buffer of the prior art example typically.

Explanation of symbols

1 Recording head (recording means)
2 Carriage 5 Main tank 7 Ink supply tube a
9 Sub tank 10 Ink supply tube b
20 Pressure buffer 201 Pressure buffer body 202 Pressure buffer film 203 Ink reservoir 204 Elastic member 205 Pressure buffer film holding member 206 Pressing member 207 Pressure regulating plate 208 Flexible film

Claims (9)

A pressure buffer connected as a part of the ink flow path of the inkjet head, the pressure buffer body having a recess on at least one surface;
A pressure buffer film fixed to an edge of the pressure buffer body so as to cover the inside of the pressure buffer body in a sealed state and having elasticity;
An ink reservoir formed by joining the pressure buffer body and the pressure buffer film;
An elastic member disposed so that one end abuts on the inner bottom surface of the pressure buffer body and the other end abuts on the pressure buffer film;
A pressure buffer comprising:   The pressure buffer according to claim 1, wherein the pressure buffer film is made of a rubber material.   The pressure buffer according to claim 1, wherein the rubber material is ethylene propylene rubber.   The pressure buffer according to claim 1, wherein the rubber material is nitrile rubber.   The pressure buffer according to claim 1, wherein the pressure buffer film is formed in a bellows shape.   The pressure buffer film holding member having an area larger than a contact area between the elastic member and the pressure buffer film is disposed between the elastic member and the pressure buffer film of the pressure buffer. The pressure buffer according to any one of claims 1 to 5.   The pressure buffer according to claim 1, wherein the pressure buffer film is fixed by a pressing member that presses the pressure buffer main body.   The pressure buffer film is covered by a pressure regulating plate that covers the pressure buffer film so as to be sandwiched between the pressure buffer body and forms a volume space similar to the ink reservoir between the pressure buffer film and the pressure buffer film. The pressure buffer according to claim 1, wherein the pressure buffer is fixed.   An ink jet head comprising the pressure buffer according to claim 1.

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