Ink jet recording apparatus, method of discharging ink from capping unit incorporated in the apparatus, and ink composition used with the apparatus

• US 6,481,826 B1
• Filed: 09/07/2000
• Issued: 11/19/2002
• Est. Priority Date: 09/07/1999
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Hara, Kazuhiko, Hayakawa, Hitoshi
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): HSIEH, SHIH WEN
• Application Number:
  US09/657,654
• Time in Patent Office: 803 Days
• Field of Search: 347/29, 347/7, 347/100, 347/30, 347/31, 347/32, 347/33, 347/22, 347/23
• US Class Current: 347/29
• CPC Class Codes: B41J 2/16508 connected with the printer frame

Abstract

A recording head has a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data. A capping unit has an internal space communicated with a negative pressure generator, and an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator. An ink discharge port is formed on a bottom portion of the internal space of the capping unit. An ink leader is provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port.

Claims

1. An ink jet recording apparatus comprising:

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data;

a capping unit having an internal space communicated with a negative pressure generator, and having an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator;

an ink discharge port formed on a bottom portion of the internal space of the capping unit;

an ink leader provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port; and

a controller for causing the negative pressure generator to apply the negative pressure to the ink discharge port in order to;

(1) suck a first amount of ink from the nozzle orifices when the capping unit seals the nozzle formation face;

(2) suck ink remaining in the internal space when the capping unit is apart from the nozzle formation face;

(3) suck a second amount of ink, which is smaller than the first amount, from the nozzle orifices when the capping unit again seals the nozzle formation face.

2. The ink jet recording apparatus as set forth in claim 1, wherein the capping unit is separated from the nozzle formation face in an unparallel attitude with respect to the nozzle formation face in accordance with a predetermined movement of the recording head;

and

wherein the ink discharge port is placed at an end portion of the bottom portion of the internal space which is closer to the nozzle formation face when the capping unit starts to be separated from the nozzle formation face.

3. The ink jet recording apparatus as set forth in claim 1, wherein the capping unit is separated from the nozzle formation face in a parallel attitude with respect to the nozzle formation face in accordance with a predetermined movement of the recording head;

and

wherein a pair of ink discharge ports are placed at both end portions of the bottom portion of the internal space.

4. An ink jet recording apparatus comprising:

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data;

a capping unit having an internal space communicated with a negative pressure generator, and having an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator;

an ink discharge port formed on a bottom portion of the internal space of the capping unit;

an ink leader provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port; and

a projection for breaking bubbles appearing due to surface tension of an ink solvent.

5. The ink jet recording apparatus as set forth in claim 4, wherein the opening of the capping unit is formed into a rectangular shape;

wherein a pair of slopes are formed in the internal space so as to extend from the opening toward the bottom portion such that a valley line defined as an intersection of the slopes extends in a longitudinal direction of the rectangular opening; and

wherein the projection is formed on each of the slopes.

6. An ink jet recording apparatus comprising:

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data;

a capping unit having an internal space communicated with a negative pressure generator, and having an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator;

an ink discharge port formed on a bottom portion of the internal space of the capping unit; and

an ink leader provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port;

wherein a pair of slopes are formed in the internal space so as to extend from toward the bottom portion;

wherein the ink leader is provided as a valley line defined as an intersection of the slopes;

wherein the ink discharge port is formed on a part of the valley line; and

wherein a cross section of the slopes is curved.

7. An ink jet recording apparatus comprising:

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data;

a capping unit having an internal space communicated with a negative pressure generator, and having an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator;

an ink discharge port formed on a bottom portion of the internal space of the capping unit; and

an ink leader provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port,

wherein a surface roughness of the bottom portion of the internal space is 25 μ

m or less.

8. An ink jet recording apparatus comprising:

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted to print on a recording medium in accordance with print data;

a capping unit having an internal space communicated with a negative pressure generator, and having an opening for sealing the nozzle formation face and sucking ink from the nozzle orifices into the internal space by negative pressure generated by the negative pressure generator;

an ink discharge port formed on a bottom portion of the internal space of the capping unit; and

an ink leader provided in the capping unit so as to generate capillary action to lead the sucked ink toward the ink discharge port;

wherein the ink leader includes a slope continuously extending from the opening to the ink discharge port, and a liquid retainer formed on a communication path between the ink discharge port and the negative pressure generator.

9. The ink jet recording apparatus as set forth in claim 8, wherein the liquid retainer is provided as a plurality of ribs protruded from an inner face of the communication path.

10. The ink jet recording apparatus as set forth in claim 8, wherein the liquid retainer is provided as a plurality of grooves formed on an inner face of the communication path.

11. The ink jet recording apparatus as set forth in claim 8, wherein the liquid retainer is provided as a liquid absorbing member provided at a connecting portion of the ink discharge port and the communication path.

12. The ink jet recording apparatus as set forth in claim 8, wherein the liquid retainer is provided as a plurality of thin tubes formed in the communication path so as to extend therealong.

13. The ink jet recording apparatus as set forth in claim 8, wherein hydrophilic treatment is applied to the liquid retainer.

14. A method of discharging ink, comprising:

providing an ink jet recording apparatus including;

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted; and

a capping unit having an internal space communicated with a negative pressure generator and formed with an ink discharge port;

sealing the nozzle formation face with the capping unit;

driving the negative pressure generator to suck ink from the nozzle orifice into the internal space of the capping unit;

separating the capping unit from the nozzle formation face, and

driving the negative pressure generator to discharge the sucked ink from the ink discharge port such that a discharging speed is controlled to such an extent that no suction vortex appears in the sucked ink.

15. A method of discharging ink, comprising:

providing an ink jet recording apparatus including;

a recording head having a nozzle formation face provided with nozzle orifices from which ink drops are jetted; and

a capping unit having an internal space communicated with a negative pressure generator and formed with an ink discharge port;

sealing the nozzle formation face with the capping unit;

driving the negative pressure generator to suck a first amount of ink from the nozzle orifice into the internal space of the capping unit;

separating the capping unit from the nozzle formation face;

driving the negative pressure generator to discharge the sucked ink from the internal space of the capping unit;

sealing again the nozzle formation face with the capping unit; and

driving the negative pressure generator to suck a second amount of ink, which is smaller than the first amount, from the nozzle orifice in order to restore a meniscus of ink in each of the nozzle orifices.