Minute droplet forming method a minute droplet forming apparatus

• US 6,811,090 B2
• Filed: 01/29/2002
• Issued: 11/02/2004
• Est. Priority Date: 08/03/1999
• Status: Expired due to Fees

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Ishikawa, Mitsuru, Kawakami, Tomonori, Yogi, Osamu
• Primary Examiner(s): BRINSON, PATRICK F
• Application Number:
  US10/058,121
• Publication Number:
  US 20020063083A1
• Time in Patent Office: 1,008 Days
• Field of Search: 239/3, 239/4, 239/102.1, 239/102.2, 239/690, 239/690.1, 239/704, 239/706-708, 239/533.1, 239/589
• US Class Current: 239/4
• CPC Class Codes: B05B 17/04 operating with special methods
• CPC Class Codes: B05B 5/025 Discharge apparatus, e.g. electrostatic spray guns
• CPC Class Codes: B41J 2/06 by electric or magnetic field
• CPC Class Codes: B41J 2002/061 Ejection by electric field of ink or of toner particles contained in ink

Abstract

A minute droplet forming apparatus comprises a nozzle 1 for storing therewithin a liquid 2 for forming a droplet 3; a substrate 5, disposed so as to face the tip of the nozzle 1, for mounting the droplet 3 dropped from the tip of the nozzle 1; and a pulse power supply 10 for applying a pulse voltage between an electrode 12 arranged in the liquid 2 within the nozzle 1 and the substrate 5. After a liquid column 2a is formed by projecting the liquid from the nozzle tip by applying the pulse voltage between substrate 5 and the electrode 12, a nickel piece 7 disposed within the nozzle 1 is moved to the tip part of the nozzle 1 by an XYZ stage 9 by way of a magnet 8, so as to enhance the fluid resistance in the nozzle tip part, thereby causing a setback force for returning the liquid 2 into the nozzle 1, by which the droplet 3 is isolated from the liquid column 2a.

Claims

1. A minute droplet forming method of electrostatic attraction type for forming a minute droplet by attracting a liquid by applying a pulse voltage to a nozzle tip containing said liquid, said method comprising:

a step of applying said pulse voltage between a substrate arranged to face said nozzle tip with a predetermined space therebetween and said liquid within said nozzle so as to project said liquid from said nozzle tip and form a liquid column; and

a step of isolating said droplet by enhancing a fluid resistance within said nozzle so as to cause a setback force for returning said liquid into said nozzle to act on said formed liquid column,

wherein each of said forming and isolating of said droplet is carried out under a saturation vapor pressure of said liquid.

2. A minute droplet forming method according to claim 1, wherein a size of said droplet to be formed is adjusted by controlling said setback force.

3. A minute droplet forming method of electrostatic attraction type for forming a minute droplet by attracting a liquid by applying a pulse voltage to a nozzle tip containing said liquid, said method comprising:

a step of applying said pulse voltage between a substrate arranged to face said nozzle tip with a predetermined space therebetween and said liquid within said nozzle so as to project said liquid from said nozzle tip and form a liquid column; and

a step of isolating said droplet by enhancing a fluid resistance within said nozzle so as to cause a setback force for returning said liquid into said nozzle to act on said formed liquid column,

wherein said nozzle is a core nozzle having a core arranged therewithin.

6. A minute droplet forming method according to claim 3, wherein a size of said droplet to be formed is adjusted by controlling said setback force.

4. A minute droplet forming apparatus comprising:

a nozzle for storing therewithin a liquid for forming a droplet;

a substrate, arranged so as to face a tip of said nozzle, for mounting said droplet dropped from said nozzle tip;

a pulse power supply for applying a pulse voltage between said liquid within said nozzle and said substrate;

a fluid regulating unit adapted to change a fluid resistance within said nozzle; and

a control unit for controlling said pulse power supply and said fluid regulating unit,

further comprising an environment maintaining unit for causing surroundings of said tip of said nozzle and said substrate to keep a saturation vapor pressure environment of said liquid within said nozzle.

5. A minute droplet forming apparatus comprising:

a nozzle for storing therewithin a liquid for forming a droplet;

a substrate, arranged so as to face a tip of said nozzle, for mounting said droplet dropped from said nozzle tip;

a pulse power supply for applying a pulse voltage between said liquid within said nozzle and said substrate;

a fluid regulating unit adapted to change a fluid resistance within said nozzle; and

a control unit for controlling said pulse power supply and said fluid regulating unit,

wherein said nozzle is a core nozzle having a core arranged within said nozzle.