Printing apparatus

• US 6,607,317 B2
• Filed: 01/10/2002
• Issued: 08/19/2003
• Est. Priority Date: 01/22/2001
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yamazaki, Atsushi, Suyama, Kiyoshi, Otsuka, Nobutoshi, Morozumi, Kazuaki
• Primary Examiner(s): Nolan, Jr., Charles H.
• Application Number:
  US10/045,950
• Publication Number:
  US 20020114652A1
• Time in Patent Office: 586 Days
• Field of Search: 400/82, 400/61, 400/70, 400/76
• US Class Current: 400/82
• CPC Class Codes: B41J 11/001 Handling wide copy materials
• CPC Class Codes: B41J 2/2103 Features not dealing with the colouring process per se, e.g. construction of printers or heads, driving circuit adaptations
• CPC Class Codes: B41J 2/51 serial printer type
• CPC Class Codes: G06K 15/105 Multipass or interlaced printing
• CPC Class Codes: G06K 2215/0094 Colour printing

Abstract

There is provided a printing apparatus which is capable of increasing the printing speed by employing a multi-head structure while maintaining or enhancing print quality. The printing apparatus prints on a print medium by using N print heads, where N is an integer equal to or larger than 2, assuming that two axes orthogonal to each other on a two-dimensional rectangular coordinate system are set to an X axis and a Y axis, each of the print heads being capable of printing M dots in a direction along the Y axis simultaneously, where M is an integer equal to or larger than 3, and at the same capable of printing M dot lines each extending in a direction along the X axis, by relative scan on the print medium in the direction along the X axis, the M dot lines being arranged side by side in the direction along the Y axis. At least two print heads of the N print heads are arranged in a manner such that selected ones of the M dot lines that can be printed by one of the at least two print heads overlap selected ones of the M dot lines that can be printed by another of the at least two print heads.

Claims

1. A printing apparatus for printing on a print medium by using N print heads, where N is an integer equal to or larger than 2, assuming that two axes orthogonal to each other on a two-dimensional rectangular coordinate system are set to an X axis and a Y axis, each of the print heads being capable of simultaneously printing M dots in a direction along the Y axis, where M is an integer equal to or larger than 3, and also being capable of printing M dot lines each extending in a direction along the X axis, by relative scan on the print medium in the direction along the X axis, the M dot lines being arranged side by side in the direction along the Y axis, at least two print heads among the N print heads being disposed such that selected ones of a first set of M dot lines printable by one of the at least two print heads overlap selected ones among a second set of M dot lines printable by another of the at least two print heads,

wherein L dot lines of the first set of M dot lines overlap L dot lines of the second set of M dot lines, where L is a natural number satisfying the relationship of L<

M; and

wherein said apparatus comprises control means for inhibiting at least one of the print heads from printing J dot line at a counterpart print head side end, where J is a natural number satisfying the relationship of J<

M/2.

2. A printing apparatus according to claim 1, wherein at least two print heads are arranged in a manner such that L+2J dot lines of the first set of M dot lines overlap L+2J dot lines of the second set of M dot lines, where L is a natural number satisfying the relationship of L≦

M−

2J.

3. A printing apparatus according to claim 1, wherein at least two print heads are arranged in a manner such that L+J dot lines of the first set of M dot lines overlap L+J dot lines of the second set of M dot lines, where L is a natural number satisfying the relationship of L≦

M−

J, and J is a natural number satisfying the relationship of J<

M.

4. A printing apparatus according to claim 3, wherein said control means controls such that the at least two print heads alternatively print each of dots of the L dot lines each extending along the X axis.

5. A printing apparatus according to claim 4, wherein said control means controls such that the at least two print heads print the dots of the L dot lines in a predetermined order.

6. A printing apparatus according to claim 5, wherein said control means controls such that the at least two print heads alternately print each of the dots of the L dot lines.

7. A printing apparatus according to claim 6, wherein the L is a plural number, and

wherein said control means controls such that each of the at least two print heads print the dots of the L dot lines in a staggered arrangement.

8. A printing apparatus according to claim 4, wherein said control means controls such that the at least two print heads print the dots of the L dot lines in a random order.

9. A printing apparatus according to claim 4, wherein the at least two print heads perform printing based on print data representing the M dot lines to be printed thereby, and

wherein each item of the print data based on which a corresponding one of the at least two print heads performs printing contains information concerning each dot as to whether the dot should be printed by the corresponding one of the at least two print heads.

10. A printing apparatus according to claim 9, wherein the at least two print heads comprise a first print head and a second print head, and

wherein the printing apparatus further comprises:

allocation pattern-determining means for determining an allocation pattern which defines a manner of allocation of the dots of the L dot lines to the at least two print heads by a pattern,

first print data-storing means for storing first print data representing M dot lines to be printed by the first print head, based on the allocation pattern, and

second print data-storing means for storing second print data representing M dot lines to be printed by the second print head, based on the allocation pattern.

11. A printing apparatus according to claim 10, wherein the first print data-storing means comprises:

pseudo first print data-storing means for storing pseudo first print data representing M dot lines to be printed by the first print head assuming the L dot lines to be printed by the first print head do not overlap the L dot lines to be printed by the second print head,

first mask pattern-forming means for forming a first mask pattern indicative of part to be printed by the first print head based on the allocation pattern, and

first print data-forming means for converting the pseudo first print data to the first print data by carrying out masking of data of the L dot lines out of the pseudo first print data based on the first mask pattern.

12. A printing apparatus according to claim 10, wherein the first print data-storing means comprises:

first individual print data-storing means for storing first individual print data representing, out of the M dot lines to be printed by the first print head, M−

L dot lines which dot not overlap the L dot lines to be printed by the second print head,

first common print data-storing means for storing first common print data representing, out of the M dot lines to be printed by the first print head, the L dot lines which overlap the L dot lines to be printed by the second print head,

and wherein the second print data-storing means comprises;

second individual print data-storing means for storing second individual print data representing, out of the M dot lines to be printed by the second print head, M−

L dot lines which dot not overlap the L dot lines to be printed by the first print head,

second common print data-storing means for storing second common print data representing, out of the M dot lines to be printed by the second print head, the L dot lines which overlap the L dot lines to be printed by the first print head, and

wherein the printing apparatus further comprises;

basic common print data-storing means for storing basic common print data representing the L dot lines in which the allocation of the dots of the L dot lines to the first print head and the second print head has not been reflected, and

common print data-allocation means for allocating the basic common print data to the first common print data and the second common print data based on the allocation pattern.

13. A printing apparatus according to claim 1, wherein the N print heads are each formed by an ink jet print head having at least M nozzles each for ejecting ink, the ink jet print head being capable of printing the M dots simultaneously by ink ejected from the M nozzles.

14. A printing apparatus according to claim 1, including print image data-storing means for storing print image data representing a print image to be printed on the print medium, and

wherein the print image data contains binary data representing execution and inhibition of printing of each dot by binary expression.

15. A printing apparatus according to claim 14, wherein the print image is a color image, and

wherein the print image data contains binary data representing each color of the color image.

16. A printing apparatus according to claim 1, wherein the print medium is in a continuous form, and mounted in the printing apparatus such that a direction along length of the print medium coincides with the direction along the X axis.