Electrostatic attraction fluid ejecting method and apparatus

• US 20070195152A1
• Filed: 08/20/2004
• Published: 08/23/2007
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kawai, Hidetsugu, Nishio, Shigeru, Murata, Kazuhiro, Deguchi, Haruhiko, Kakiwaki, Shigeaki
• Granted Patent: US 7,922,295 B2
• Time in Patent Office: Days
• US Class Current: 347/112
• CPC Class Codes: B41J 2/06 by electric or magnetic field
• CPC Class Codes: B41J 2/095 electric field-control type
• CPC Class Codes: B41J 2/16511 Constructions for cap positioning B41J2/16547 takes precedence
• CPC Class Codes: B41J 2/185 Ink-collectors; Ink-catchers

Abstract

An ink jet apparatus electrifies ink (2) in a nozzle (4), and ejects the ink (2) from an ink ejecting hole (4b) onto a printing medium (8) by a first electric field generated between the nozzle (4) and the printing medium (8). The ink jet apparatus includes an ink catching device which includes an ink catching portion (14) provided at a position adjacent to the nozzle (4) and catches an ejected substance ejected from the nozzle (4). In addition, between the nozzle (4) and the ink catching portion (14), the ink jet apparatus applies a voltage for generating a second electric field which (i) causes the ejected substance, which is formed from the ink (2) or the ink (2) whose viscosity is changed, to be ejected from the nozzle (4) and (ii) causes the ink catching portion to attract the ejected substance. With this, in a configuration which utilizes an electrostatic force to eject fluid, it is possible to promptly remove a clogging of an ejection head at any position, and it is also possible to realize less initial ejection fluctuation and improve the reliability of ejection.

Claims

1. An electrostatic attraction fluid ejecting apparatus which electrifies fluid supplied in a nozzle, and ejects the fluid from a nozzle hole onto an ejection target member by a first electric field generated between the nozzle and the ejection target member, the electrostatic attraction fluid ejecting apparatus comprising:

catching means, provided at a position adjacent to the nozzle and including a conductive portion, for catching an ejected substance ejected from the nozzle; and

voltage applying means for applying a voltage between the nozzle and the conductive portion of said catching means, the voltage being for generating a second electric field which causes the ejected substance, which is formed from the fluid or the fluid whose viscosity is changed, to be ejected from the nozzle and causes the conductive portion to attract the ejected substance.

2. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein:

said catching means includes a catching portion which (i) is in the form of a container whose surface opposed to a top portion of the nozzle has an opening, and (ii) has the conductive portion, and

the catching portion is provided at a catching position for catching the ejected substance from the nozzle, that is, the catching portion is provided such that a normal line of a central point of a bottom surface of the catching portion passes through the top portion of the nozzle.

3. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein:

said catching means includes a catching portion which (i) is in the form of a container whose surface opposed to a top portion of the nozzle has an opening, and (ii) has the conductive portion; and

the conductive portion is provided at a bottom wall portion of the catching portion.

4. The electrostatic attraction fluid ejecting apparatus as set forth in claim 3, wherein, on or above the conductive portion in the catching portion, an absorber member capable of absorbing the fluid is provided.

5. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein:

said catching means includes a catching portion which (i) is in the form of a container whose surface opposed to a top portion of the nozzle has an opening, and (ii) has the conductive portion; and

the conductive portion is provided so as to project from a partial area of a bottom wall portion of the catching portion toward the opening.

6. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein said catching means includes:

a catching portion having the conductive portion;

a supporting portion which supports the catching portion so as to allow the catching portion to move; and

a moving portion which causes the catching portion to move to (i) a catching position for catching the ejected substance ejected from the nozzle and (ii) an escaped position which is further from the nozzle than the catching position.

7. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein:

said catching means includes a catching portion which (i) is in the form of a container whose surface opposed to a top portion of the nozzle has an opening, and (ii) has the conductive portion;

the catching portion has (i) a solution path whose one end opens at an external surface of the catching portion and whose another end opens at an internal surface of the catching portion and (ii) a discharging opening for discharging a solution from the catching portion; and

said one end of the solution path is connected with solution supplying means for supplying the solution for dissolving the ejected substance caught by the catching portion.

8. The electrostatic attraction fluid ejecting apparatus as set forth in claim 7, wherein:

said solution supplying means has a function of controlling the amount of solution supplied to the catching portion; and

the discharging opening is connected with collecting means for collecting the solution in the catching portion in accordance with an instruction from said solution supplying means.

9. The electrostatic attraction fluid ejecting apparatus as set forth in claim 8, wherein said catching means includes:

a catching portion having the conductive portion;

a supporting portion which supports the catching portion so as to allow the catching portion to move; and

a moving portion which causes the catching portion to move to (i) a catching position for catching the ejected substance ejected from the nozzle and (ii) an escaped position which is further from the nozzle than the catching position and at which a bottom surface of the catching portion is substantially in parallel with a surface of the solution supplied to the catching portion.

10. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, wherein said voltage applying means carries out such a voltage applying operation that the first electric field is higher in intensity than the second electric field.

11. The electrostatic attraction fluid ejecting apparatus as set forth in claim 1, comprising a counter electrode positioned at a back surface of the ejection target member, wherein:

said voltage applying means applies a voltage for generating the first electric field between the nozzle and the counter electrode; and

when generating the second electric field between the nozzle and the conductive portion of said catching means, a voltage applied to the counter electrode is set to have a same polarity as a voltage applied to the nozzle.

12. An electrostatic attraction fluid ejecting method which, as a regular ejection operation, electrifies fluid supplied in a nozzle, and ejects the fluid from a nozzle hole onto an ejection target member by a first electric field generated between the nozzle and the ejection target member, wherein

as a preliminary ejection operation or a maintenance operation, (i) catching means, including a conductive portion, for catching an ejected substance ejected from the nozzle is provided at a position adjacent to the nozzle, and (ii) a voltage for generating a second electric field which causes the ejected substance, which is formed from the fluid or the fluid whose viscosity is changed, to be ejected from the nozzle and causes the conductive portion to attract the ejected substance is applied between the nozzle and the conductive portion of said catching means.

13. An electrostatic attraction fluid ejecting method which, as a regular ejection operation, electrifies fluid supplied in a nozzle, and ejects the fluid from a nozzle hole onto an ejection target member by a first electric field generated between the nozzle and the ejection target member, wherein

before carrying out the regular ejection operation, as a preliminary ejection operation, (i) catching means, including a conductive portion, for catching an ejected substance ejected from the nozzle is provided at a position adjacent to the nozzle, and (ii) a voltage for generating a second electric field which causes the ejected substance, which is formed from the fluid, to be ejected from the nozzle and causes the conductive portion to attract the ejected substance is applied between the nozzle and the conductive portion of said catching means.

14. The electrostatic attraction fluid ejecting method as set forth in claim 13, wherein, before carrying out the preliminary ejection operation, as a maintenance operation, (i) said catching means, including the conductive portion, for catching the ejected substance ejected from the nozzle is provided at the position adjacent to the nozzle, and (ii) the voltage for generating the second electric field which causes the ejected substance, which is formed from the fluid whose viscosity is changed, to be ejected from the nozzle and causes the conductive portion to attract the ejected substance is applied between the nozzle and the conductive portion of said catching means.