Continuous inkjet printer

• US 6,595,629 B2
• Filed: 12/07/2001
• Issued: 07/22/2003
• Est. Priority Date: 12/08/2000
• Status: Expired due to Fees

• Current Assignee: 658868 N.B. INC. (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: Shibaishi, Takashi, Tachibana, Yoshiaki
• Primary Examiner(s): Nguyen, Lamson
• Assistant Examiner(s): FEGGINS, KRISTAL J
• Application Number:
  US10/005,245
• Publication Number:
  US 20020071010A1
• Time in Patent Office: 592 Days
• Field of Search: 347/77, 347/73-74, 347/75-76, 347/82, 347/81, 347/53, 347/43, 347/80, 347/6, 438/21, 298/901
• US Class Current: 347/77
• CPC Class Codes: B41J 2/09 Deflection means

Abstract

Ink particles that start flying toward the printing medium P earlier than or later than the ink particles for the line central area are used as ink particles for the line ends. Accordingly, it is possible to compensate for the affects of electrical charges onto the flying path of the ink particles for the line end portions, reducing the amount of bending at the ends of the printed line such that the bend is not noticeable, thereby improving the quality of printing to satisfy consumer demands.

Claims

1. A continuous inkjet printer, comprising:

a continuous print head having a row of ejection nozzles, the row of ejection nozzles including a plurality of ejection nozzles which are arranged to be located at a plurality of nozzle positions defined along a first predetermined direction, the row of ejection nozzles being located at a predetermined position along a second predetermined direction that is substantially perpendicular to the first predetermined direction, each ejection nozzle ejecting successive ink particles continuously in a third predetermined direction that is substantially perpendicular to both of the first and second predetermined directions, thereby allowing the ejection nozzle row to eject successive rows of ink particles continuously in the third predetermined direction;

a conveying unit conveying a printing medium relative to the continuous print head in the second predetermined direction;

a deflecting unit receiving successive groups of control data, and selectively deflecting the ink particles in the successive ink particle rows, based on the received successive control data groups, thereby selectively preventing the ink particles from reaching the printing medium;

a judging unit receiving a print data group for one of the successive ink particle rows, and judging whether or not the print data group includes straight-line-end data indicative of an end portion of a straight-line that extends in the first predetermined direction; and

a control data producing unit producing, when the print data group is judged to include the straight-line-end data at some nozzle position, deflection control data for deflecting an ink particle at the subject nozzle position in the subject ink particle row and producing first non-deflection control data for failing to deflect a first ink particle at the subject nozzle position in a first ink particle row that is different from the subject ink particle row.

2. A continuous inkjet printer as claimed in claim 1,

wherein the print data group includes a plurality of sets of print data in correspondence with the plurality of nozzle positions, each paint data being either one of dot-print data and non-dot print data, the straight-line-end data being comprised from dot-print data, and

wherein the control data producing unit produces one group of control data based on the print data group, by producing the deflection control data based on the straight-line-end data, by producing non-deflection control data based on the dot-print data other than the straight-line-end data, and producing deflection control data based on the non-dot print data.

3. A continuous inkjet printer as claimed in claim 2,

wherein the judging unit includes:

a first determining unit determining whether dot-print data are arranged in the group of print data at three or more adjacent nozzle positions and whether non-dot print data is located at one or more nozzle position adjacent to the three or more adjacent nozzle positions; and

a second determining unit determining, as the straight-line-end data, dot-print data that is located in one of the three or more adjacent nozzle positions and that is located directly adjacent to the non-dot print data at the one or more nozzle position.

4. A continuous inkjet printer as claimed in claim 2,

wherein the control data producing unit includes:

a data receiving unit receiving the print data group;

a dummy data adding unit adding several duty groups of print data to the print data group, each dummy print data group being comprised of a plurality of non-dot print data in correspondence with the plurality of nozzle positions;

a data modifying unit modifying, when the print data group is judged to include the straight-line-end date at the some nozzle position, the straight-line-end data into non-dot print data, the data modifying unit further modifying non-dot print data, at the subject nozzle position in one of the several dummy print data groups, into dot-print data; and

a control data generating unit generating one control data group based on the print data group and several control data groups based on the several dummy print data groups, the control data generating unit outputting the one control data group and the several control data groups to the deflecting unit as the successive control data groups.

5. A continuous inkjet printer as claimed in claim 2,

wherein the deflecting unit includes a plurality of electrodes, which are located in correspondence with the plurality of nozzle positions and which are located in one side of the predetermined position with respect to the second predetermined direction, each electrode being applied with corresponding control data in the control data group, the deflection-control data in the control data group including a voltage signal of a predetermined polarity, the non-deflection control data in the control data group including a zero voltage signal, whereby the plurality of electrodes, upon receipt of the control data group, selectively electrically charge the ink particles in the corresponding ink particle row to a polarity opposite to the predetermined polarity, and electrostatically attracting the electrically-charged ink particles in a direction toward the plurality of electrodes.

6. A continuous inkjet printer as claimed in claim 5, wherein the deflecting unit further includes a collecting unit, located in the downstream side of the plurality of electrodes in the third predetermined direction, for receiving and collecting the electrically-charged ink particles attracted by the plurality of electrodes.

7. A continuous inkjet printer as claimed in claim 6, wherein the collecting unit is applied with an electric voltage of a polarity opposite to that of the electrically-charged ink particles, thereby electrostatically attracting the electrically-charged ink particles in a direction toward the collecting unit.

8. A continuous inkjet printer as clamed in claim 1, wherein the deflecting unit has a structure for deflecting, in response to the deflection-control data in the control data group, a corresponding ink particle in the corresponding ink particle row in a direction opposite to the second predetermined direction, the first ink particle row being ejected from the ejection nozzle row earlier than the subject ink particle row.

9. A continuous inkjet printer as claimed in claim 1, wherein the deflecting unit has a structure for deflecting, in response to the deflection-control data in the control data group, a corresponding ink particle in the corresponding ink particle row in a direction the same as the second predetermined direction, the first ink particle row being ejected from the ejection nozzle row later than the subject ink particle row.

10. A continuous inkjet printer as claimed in claim 1,

wherein the print data group, judged to include the straight-line-end print data, further includes next-to-end data in one next-to-end nozzle position that is directly adjacent to the subject nozzle position for the straight-line-end print data, the next-to-end data indicating a part of the straight line adjacent to the end portion, and

wherein the control data producing unit further produces deflection control data for deflecting another ink particle at the next-to-end nozzle position in the subject ink particle row and produces non-deflection control data for failing to deflect a second ink particle at the next-to-end nozzle position in a second ink particle row that is different from the subject ink particle row.

11. A continuous inkjet printer as claimed in claim 10, wherein the second ink particle row is different from the first ink particle row.

12. A continuous inkjet printer as claimed in claim 11, wherein the deflecting unit has a structure for deflecting, in response to the deflection-control data in the control data group, a corresponding ink particle in the corresponding ink particle row in a direction opposite to the second predetermined direction, the first ink particle row being ejected from the ejection nozzle row earlier than the second ink particle row, the second ink particle row being ejected from the ejection nozzle row earlier than the subject ink particle row.

13. A continuous inkjet printer as claimed in claim 11, wherein the deflecting unit has a structure for deflecting, in response to the deflection-control data in the control data group, a corresponding ink particle in the corresponding ink particle row in a direction the same as the second predetermined direction, the first ink particle row being ejected from the ejection nozzle row later than the second ink particle row, the second ink particle row being ejected from the ejection nozzle row later than the subject ink particle row.

14. A method of printing a straight line with a continuous inkjet printer, the continuous inkjet printer including a continuous print head, a conveying unit, and a deflecting unit, the continuous print head having a row of ejection nozzles, the row of election nozzles including a plurality of ejection nozzles which are arranged to be located at a plurality of nozzle positions defined along a first predetermined direction, the row of ejection nozzles being located at a predetermined position along a second predetermined direction that is substantially perpendicular to the first predetermined direction, each ejection nozzle ejecting successive ink particles continuously in a third predetermined direction that is substantially perpendicular to both of the first and second predetermined directions, thereby allowing the ejection nozzle row to eject successive rows of ink particles continuously in the third predetermined direction, the conveying unit conveying a printing medium relative to the continuous print head in the second predetermined direction, the deflecting unit receiving successive groups of control data, and selectively deflecting the ink particles in the successive ink particle rows, based on the received successive control data groups, thereby selectively preventing the ink particles from reaching the printing medium, the method comprising the steps of:

receiving a print data group for one of the successive ink particle rows;

judging whether or not the print data group includes straight-line-end data indicative of an end portion of a straight-line that extends in the first predetermined direction; and

producing, when the print data group is judged to include the straight-line-end data at some nozzle position, deflection control data for deflecting an ink particle at subject nozzle position in the subject ink particle row and producing first non-deflection control data for failing to deflect a first ink particle at the subject nozzle position in a first ink particle row that is different from the subject ink particle row.

15. A method as claimed in claim 14, wherein the print data group, judged to include the straight-line-end print data, further includes next-to-end data in one next-to-end nozzle position that is directly adjacent to the subject nozzle position for the straight-line-end print data, the next-to-end data indicating a part of the straight line adjacent to the end portion, and

further comprising the step of producing deflection control data for deflecting another ink particle at the next-to-end nozzle position in the subject ink particle row and produces non-deflection control data for failing to deflect a second ink particle at the next-to-end nozzle position in a second ink particle row that is different from the subject ink particle row.

16. A method as claimed in claim 15, wherein the second ink particle row is different from the first ink particle row.