Image forming apparatus and threshold setting method
AssigneeRicoh Company, Ltd.
InventorToshihide Inaba
Life of this patent
Estimating the term…
Abstract
A moving unit causes a relative movement of a web and a mark detecting unit for detecting a ground color of the web and a mark color in a predetermined direction. A measuring unit measures a measurement value corresponding to a moving amount of the mark detecting unit with respect to the web in a time from when a detected color is switched from the ground color to the mark color till when a detected color is back to the ground color. A setting unit sets a threshold used for determining whether the color detected is the ground color or the mark color on the basis of the mark color detected by the mark detecting unit at the time when the mark detecting unit is moved in a reverse direction for a distance of half the measurement value since the color detected is back to the ground color.
Claims9
An image forming apparatus that forms an image on a web with reference to a position of a positioning mark on the web, the image forming apparatus comprising:
- a moving unit that causes a relative movement of the web and a mark detecting unit in a predetermined direction, the mark detecting unit detecting a ground color of the web and a mark color which is a color of the positioning mark;
- and
- a control device that measures a measurement value corresponding to a moving amount of the mark detecting unit with respect to the web in a forward direction in a time from when a color detected by the mark detecting unit is switched from the ground color to the mark color till when a color detected by the mark detecting unit is switched back to the ground color,
- wherein the control device causes the moving unit to relatively move the web and the mark detecting unit in a reverse direction for a distance of half the measurement value from when the color detected is switched back to the ground color and measures a mark detection signal that is detected by the mark detecting unit at this distance, and
- wherein the control device sets a threshold used for determining whether the color detected is the ground color or the mark color on the basis of the measured mark detection signal.
A threshold setting method executed in an image forming apparatus for forming an image on a web with reference to a position of a positioning mark on the web, the threshold setting method comprising:
- causing, by a moving unit, a relative movement of the web and a mark detecting unit, which detects a ground color of the web and a mark color that is a color of the positioning mark, in a predetermined direction;
- measuring, by a control device, a measurement value corresponding to a moving amount of the mark detecting unit with respect to the web in a forward direction in a time from when a color detected by the mark detecting unit is switched from the ground color to the mark color till when a color detected by the mark detecting unit is switched back to the ground color;
- causing, by the control device, the moving unit to relatively move the web and the mark detecting unit in a reverse direction for a distance of half the measurement value from when the color detected is switched back to the ground color and measuring, by the control device, a mark detection signal that is detected by the mark detecting unit at this distance, and
- setting, by the control device, a threshold used for determining whether the color detected is the ground color or the mark color on the basis of the measured mark detection signal.
Dependencies are inferred from the claim text.