Method of obtaining correction value of optical sensor and recording apparatus

• US 20070055724A1
• Filed: 09/07/2006
• Published: 03/08/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Hashii, Kazuhiro, Nakata, Satoshi, Harada, Kazumasa, Adachi, Hirohisa
• Granted Patent: US 7,830,564 B2
• Time in Patent Office: Days
• US Class Current: 708/800
• CPC Class Codes: B41J 11/0095 Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end
• CPC Class Codes: B41J 11/46 by marks or formations on the paper being fed

Abstract

A method of obtaining a correction value of an optical sensor detecting an edge of the medium so as to generate detection information, includes: acquiring edge information on an edge position of one of opposite edges of the medium based on the detection information; forming on the medium a correction value obtainment pattern including lines that are arranged at a fixed interval in a first direction and parallel to a second direction perpendicular to the first direction so as to form a step shape and that include a reference line spaced a first distance from the edge position in the first direction and parallel to the second direction, based on the edge information; specifying a line spaced the first distance from the edge position in the first direction and corresponding to one of the lines of the correction value obtainment pattern, by means of actual measurement performed by an operator; obtaining a second distance in the first direction between the specified line and the reference line, based on line information on the specified line; and determining the second distance as an absolute value of the correction value.

Claims

1. A method of obtaining a correction value used for correcting a detection error in an optical sensor opposing a transport path in which a medium is transported and operable to detect a change in optical reflectance of the transport path to thereby detect an edge of the medium so as to generate detection information, the method comprising:

acquiring edge information on an edge position of one of opposite edges of the medium based on the detection information;

forming on the medium a correction value obtainment pattern including lines that are arranged at a fixed interval in a first direction and parallel to a second direction perpendicular to the first direction so as to form a step shape and that include a reference line which is located at a position spaced a first distance from the edge position in the first direction and which is parallel to the second direction, based on the edge information;

specifying a line which is located at a position spaced the first distance from the edge position in the first direction and which corresponds to one of the lines of the correction value obtainment pattern, by means of actual measurement performed by an operator;

obtaining a second distance in the first direction between the specified line and the reference line, based on line information on the specified line; and

determining the second distance as an absolute value of the correction value.

2. The method according to claim 1, wherein

the first direction is a main scanning direction,

the second direction is a sub scanning direction, and

the opposite edges of the medium are opposite edges of the medium in the second direction.

3. The method according to claim 1, wherein

the first direction is a sub scanning direction,

the second direction is a main scanning direction, and

the opposite edges of the medium are a leading edge and a trailing edge of the medium in the first direction.

4. The method according to claim 3, wherein

in the acquiring process of the edge information, the edge position includes two edge points spaced at a predetermined interval from each other in the second direction,

the method further comprising:

obtaining an inclination angle between a line connecting the two edge points and a line parallel to the second direction based on the edge information; and

obtaining an inclination error caused by inclination of the medium with respect to the line parallel to the second direction, based on the inclination angle, and

in the determining process, a sum of the second distance and the inclination error is determined as the absolute value of the correction value.

5. The method according to claim 4, further comprising:

obtaining an intermediate point between the two edge points, and

obtaining a third distance in the second direction between an intermediate point of the specified line and the intermediate point between the two edge points,

wherein the inclination error is defined as Hb, the third distance is defined as W, and the inclination angle is defined as θ

, such that the following equation is satisfied,

Hb=W×

tan θ

.

6. The method according to claim 4, further comprising:

obtaining an intermediate point between the two edge points,

wherein an intermediate point of the reference line corresponds to the intermediate point between the two edge points in the first direction.

7. A recording apparatus comprising:

a transporter, operable to transport a recording medium in a transport path;

an optical sensor, opposing the transport path, and operable to detect a change in optical reflectance of the transport path to thereby detect an edge of the recording medium so as to generate detection information;

a controller, operable to acquire edge information on an edge position of one of opposite edges of the recording medium based on the detection information;

a recording head, operable to form on the recording medium a correction value obtainment pattern including lines that are arranged at a fixed interval in a first direction and parallel to a second direction perpendicular to the first direction so as to form a step shape and that include a reference line which is located at a position spaced a first distance from the edge position in the first direction and which is parallel to the second direction, based on the edge information; and

an ejector, operable to eject the recording medium on which the correction value obtainment pattern has been formed, wherein

an operator specifies a line which is located at a position spaced the first distance from the edge position in the first direction and which corresponds to one of the lines of the correction value obtainment pattern by means of actual measurement, and inputs line information on the specified line to the controller, and

the controller obtains a second distance in the first direction between the specified line and the reference line based on the line information, and determines the second distance as an absolute value of the correction value.

8. The recording apparatus according to claim 7, wherein

the first direction is a main scanning direction,

the second direction is a sub scanning direction, and

the opposite edges of the recording medium are opposite edges of the recording medium in the second direction.

9. The recording apparatus according to claim 7, wherein

the first direction is a sub scanning direction,

the second direction is a main scanning direction, and

the opposite edges of the recording medium are a leading edge and a trailing edge of the recording medium in the first direction.

10. The recording apparatus according to claim 9, wherein

the edge position includes two edge points spaced at a predetermined interval from each other in the second direction,

the controller obtains an inclination angle between a line connecting the two edge points and a line parallel to the second direction based on the edge information,

the controller obtains an inclination error caused by inclination of the recording medium with respect to the line parallel to the second direction based on the inclination angle, and

the controller determines a sum of the second distance and the inclination error as the absolute value of the correction value.

11. The recording apparatus according to claim 10, wherein

the controller obtains an intermediate point between the two edge points,

the controller obtains a third distance in the second direction between an intermediate point of the specified line and the intermediate point between the two edge points, and

the inclination error is defined as Hb, the third distance is defined as W, and the inclination angle is defined as θ

, such that the following equation is satisfied,

Hb=W×

tan θ

.

12. The recording apparatus according to claim 10, wherein

the controller obtains an intermediate point between the two edge points, and

an intermediate point of the reference line corresponds to the intermediate point between the two edge points in the first direction.