Image printing apparatus and method for calibrating image printing apparatus

An image printing apparatus comprising:

• a printing section that performs printing on a print target medium;
• a moving section that can move in a predetermined main scan direction;
• an edge-detecting section that is mounted on the moving section and outputs, by utilizing photoelectric conversion, a voltage that changes across each edge of the print target medium;
• a position-detecting section that detects a position of the moving section;
• a reference stage that has an edge at predetermined reference position, the reference stage being formed in such a manner that the edge-detecting section outputs a voltage that changes across the edge of the reference stage;
• and
• a calibrating section that commands the moving section to move in such a manner that the edge-detecting section passes through the one edge and the another edge of the reference stage, commands the position-detecting section to detect the position of the moving section at a point at which a voltage outputted by the edge-detecting section changes during movement of the moving section at a measured position, and calibrates the edge-detecting section based on the measured position and the reference position;
• wherein the reference stage has two edges one of which is provided at a predetermined first reference position whereas another thereof is provided at a predetermined second reference position;
• the calibrating section commands the position-detecting section to detect, as a first measured position, the position of the moving section at a point at which a voltage outputted by the edge-detecting section changes during the movement of the moving section in which, as the moving section moves, the edge-detecting section moves from a surface area of the reference stage so as to pass through the one edge of the reference stage, and thereafter, the calibrating section commands the position-detecting section to detect, as a second measured position, the position of the moving section at a point at which a voltage outputted by the edge-detecting section changes during the movement of the moving section in which, as the moving section moves, the edge-detecting section moves from the surface area of the reference stage so as to pass through the another edge of the reference stage;
• the calibrating section calculates a first calibration value in proportion to a difference between the first measured position and the first reference position and a second calibration value;
• and
• the calibrating section performs calibration by subtracting the first calibration value from a position of one edge of the print target medium detected by the edge-detecting section, which corresponds to the first reference position, and by adding the second calibration value to a position of another edge of the print target medium detected by the edge-detecting section, which corresponds to the second reference position.

An image printing apparatus comprising:

• a printing mechanism that performs printing on a print target medium;
• a carriage that can move in a predetermined main scan direction;
• an paper-width detection device that is mounted on the carriage and outputs, by utilizing photoelectric conversion, a voltage that changes across each edge of the print target medium;
• a linear encoder that detects a position of the carriage;
• a reference stage that has one edge and another edge in such a manner that the reference stage has a predetermined reference width therebetween, the reference stage being formed in such a manner that the paper-width detection device outputs a voltage that changes across each edge of the reference stage;
• and
• a central processing unit that commands the carriage to move in such a manner that the paper-width detection device passes through the one edge and the another edge of the reference stage, commands the linear encoder to detect the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during movement of the carriage at each measured position, calculates a measured width based on each measured position, and calibrates the paper-width detection device based on the measured width and the reference width;
• wherein the central processing unit commands the linear encoder to detect, as a first measured position, the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during the movement of the carriage in which, as the carriage moves, the paper-width detection device moves from a surface area of the reference stage so as to pass through the one edge of the reference stage, and thereafter, the central processing unit commands the linear encoder to detect, as a second measured position, the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during the movement of the carriage in which, as the carriage moves, the paper-width detection device moves from the surface area of the reference stage so as to pass through the another edge of the reference stage;
• the central processing unit calculates a calibration value in proportion to a difference between the measured width and the reference width;
• and
• the central processing unit performs calibration by subtracting the calibration value from a position of one edge of the print target medium detected by the paper-width detection device and by adding the calibration value to a position of another edge of the print target medium detected by the paper-width detection device.

An image printing apparatus comprising:

• a printing mechanism that performs printing on a print target medium;
• a carriage that can move in a predetermined main scan direction;
• an paper-width detection device that is mounted on the carriage and outputs, by utilizing photoelectric conversion, a voltage that changes across each edge of the print target medium;
• a linear encoder that detects a position of the carriage;
• a reference stage that has an edge at a predetermined reference position, the reference stage being formed in such a manner that the paper-width detection device outputs a voltage that changes across the edge of the reference stage;
• and
• a central processing unit that commands the carriage to move in such a manner that the paper-width detection device passes through the one edge and the another edge of the reference stage, commands the linear encoder to detect the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during movement of the carriage at a measured position, and calibrates the paper-width detection device based on the measured position and the reference position;
• wherein the reference stage has two edges one of which is provided at a predetermined first reference position whereas another thereof is provided at a predetermined second reference position;
• the central processing unit commands the linear encoder to detect, as a first measured position, the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during the movement of the carriage in which, as the carriage moves, the paper-width detection device moves from a surface area of the reference stage so as to pass through the one edge of the reference stage, and thereafter, the central processing unit commands the linear encoder to detect, as a second measured position, the position of the carriage at a point at which a voltage outputted by the paper-width detection device changes during the movement of the carriage in which, as the carriage moves, the paper-width detection device moves from the surface area of the reference stage so as to pass through the another edge of the reference stage;
• the central processing unit calculates a first calibration value in proportion to a difference between the first measured position and the first reference position and a second calibration value;
• and
• the central processing unit performs calibration by subtracting the first calibration value from a position of one edge of the print target medium detected by the paper-width detection device, which corresponds to the first reference position, and by adding the second calibration value to a position of another edge of the print target medium detected by the paper-width detection device, which corresponds to the second reference position.