Printing apparatus and control method thereof

Patent metadata

Field	Value
Publication number	US-9016820-B2
Application number	US-201213565156-A
Country	US
Kind code	B2
Filing date	Aug 2, 2012
Priority date	Aug 24, 2011
Publication date	Apr 28, 2015
Grant date	Apr 28, 2015

Abstract

A printing apparatus includes a printhead having a first nozzle array and a second nozzle array for discharging ink, a reading unit, a first obtaining unit configured to obtain first information about a shift amount between printing positions for the first and second nozzle arrays, a print control unit configured to print first and second distance detection patterns with the first and second nozzle arrays, a second obtaining unit configured to obtain second information about a distance between printing positions of the first and second distance detection patterns in accordance with a result of the first and second distance detection patterns, and a determination unit configured to determine an ink discharge timing in accordance with the first and second information.

First claim

What is claimed is:

1. A printing apparatus comprising:
a printhead provided with a first nozzle array and a second nozzle array for discharging ink onto a printing medium, wherein the first nozzle array and the second nozzle array are arranged in a predetermined direction;
a scanning unit configured to scan the printhead in the predetermined direction;
a first obtaining unit configured to obtain, for each of a plurality of positions on the printing medium in the predetermined direction, first information about a shift amount, in the predetermined direction, between a printing position of ink discharged from the first nozzle array and a printing position of ink discharged from the second nozzle array;
a print control unit configured to cause the printhead to print a first distance detection pattern on the printing medium by discharging ink from the first nozzle array and to print a second distance detection pattern at a position spaced apart from the first distance detection pattern in the predetermined direction by discharging ink from the second nozzle array;
a second obtaining unit configured to obtain, based on the first distance detection pattern and the second distance detection pattern, second information about a distance between a printing position of the first distance detection pattern and a printing position of the second distance detection pattern; and
a determination unit configured to determine, based on the first information obtained by the first obtaining unit and the second information obtained by the second obtaining unit, a relative ink discharge timing between the first nozzle array and the second nozzle array in the scanning by the scanning unit, by correcting the distance between the printing position of the first distance detection pattern and the printing position of the second distance detection pattern which is indicated by the second information obtained by the second obtaining unit using the first information obtained by the first obtaining unit.

2. The apparatus according to claim 1 , wherein the first information contains one of:
variation information of a distance between the printhead and the printing medium in the predetermined direction,
variation information of an orientation of the printhead in the predetermined direction, and
variation information of a surface state of the printing medium in the predetermined direction upon printing with ink on the printing medium.

3. A printing apparatus comprising:
a printhead provided with a first nozzle array and a second nozzle array for discharging ink onto a printing medium, wherein the first nozzle array and the second nozzle array are arranged in a predetermined direction;
a scanning unit configured to scan the printhead in the predetermined direction;
a print control unit configured to cause the printhead:
to perform first print control of printing a first distance detection pattern on the printing medium by discharging ink from the first nozzle array and to print a second distance detection pattern at a different position in a direction intersecting the predetermined direction with respect to a printing position of the first distance detection pattern by discharging ink from the second nozzle array, and
to perform second print control of printing a first density detection pattern by discharging ink from the first nozzle array and to print a second density detection pattern by discharging ink from the second nozzle array, at printing positions different from the printing positions of the first distance detection pattern and the second distance detection pattern;
a reading control unit configured to perform first reading control of reading the first distance detection pattern and the second distance detection pattern, and second reading control of reading the first density detection pattern and the second density detection pattern;
an obtaining unit configured to obtain a discharge timing of the second nozzle array in the second print control based on a result of reading in the first reading control; and
a determination unit configured to determine a relative ink discharge timing between the first nozzle array and the second nozzle array in the scanning by the scanning unit, by correcting a distance between the printing positions of the first distance detection pattern and the second distance detection pattern using a result of reading in the second reading control.

4. The apparatus according to claim 3 , wherein in the second print control, a plurality of first density detection patterns and a plurality of second density detection patterns are printed in the predetermined direction to change an overlapping amount between dots of the first density detection pattern and dots of the second density detection pattern.

5. A method of controlling a printing apparatus, the printing apparatus including a printhead provided with a first nozzle array and a second nozzle array for discharging ink onto a printing medium, wherein the first nozzle array and the second nozzle array are arranged in a predetermined direction, and a scanning unit configured to scan the printhead in the predetermined direction, the control method comprising:
obtaining, for each of a plurality of positions on the printing medium in the predetermined direction, first information about a shift amount, in the predetermined direction, between a printing position of ink discharged from the first nozzle array and a printing position of ink discharged from the second nozzle array;
causing the printhead to print a first distance detection pattern on the printing medium by discharging ink from the first nozzle array, and printing a second distance detection pattern at a printing position different from a printing position of the first distance detection pattern in the predetermined direction by discharging ink from the second nozzle array;
obtaining, based on the first distance detection pattern and the second distance detection pattern, second information about a distance between the printing position of the first distance detection pattern and the printing position of the second distance detection pattern; and
determining, based on the first information and the second information, a relative ink discharge timing between the first nozzle array and the second nozzle array in the scanning by the scanning unit, by correcting the distance between the printing position of the first distance detection pattern and the printing position of the second distance detection pattern using the first information.

6. The apparatus according to claim 1 , further comprising a reading unit configured to measure a distance between the printhead and the printing medium for each of the plurality of positions,
wherein the first obtaining unit obtains information relating to the distance between the printhead and the printing medium for each of the plurality of positions as the first information based on the measurement result by the reading unit.

7. The apparatus according to claim 1 , wherein the first nozzle array and the second nozzle array discharge ink dots whose colors are different from each other.

8. The apparatus according to claim 3 , further comprising a reading unit configured to measure a distance between the printhead and the printing medium for each of a plurality of printing positions,
wherein the result of reading in the first reading control includes the distance between the printhead and the printing medium for each of the plurality of printing positions.

9. The apparatus according to claim 3 , wherein the first nozzle array and the second nozzle array discharge ink dots whose colors are different from each other.

10. The apparatus according to claim 1 , wherein the firs

Assignees

• Uchida Naoki
• Canon Kk

Inventors

• Uchida Naoki

Classifications

• B41J29/38 Primary

  Drives, motors, controls or automatic cut-off devices for the entire printing mechanism · CPC title

• B41J2/2139

  Compensation for malfunctioning nozzles creating dot place or dot size errors (generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045) · CPC title