Test chart used for calibration in image forming apparatus
First Claim
Patent Images
1. An image forming apparatus comprising:
- an image forming station configured to form an image on a sheet;
conveyance rollers configured to convey the sheet on which the image is formed;
a sensor configured to measure, based on an accumulation time, reflected light from a measurement image that is formed on a sheet conveyed by the conveyance rollers; and
a processor configured to cause execution of tasks including;
an image forming task that controls the image forming stations to form a plurality of measurement images on a sheet, wherein the plurality of measurement images includes a first measurement image and a second measurement image, anda measurement task that controls the sensor to measure the first measurement image based on a first accumulation time, and measure the second measurement image based on a second accumulation time, wherein the second accumulation time is longer than the first accumulation time,wherein the conveyance rollers are configured to reverse the conveyance direction of the sheet,wherein the processor is further configured to execute the measurement task after reversal of the conveyance direction of the sheet on which the plurality of measurement images is formed, andwherein a length of the first measurement image in a conveyance direction in which the conveyance rollers convey the sheet is shorter than a length of the second measurement image in the conveyance direction.
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Abstract
Multiple measurement images are formed in a test chart. Reflected light from the test patterns is received by light receiving elements of a color sensor for an accumulation time that is determined for the respective test patterns. The lengths of the test patterns in the conveyance direction of the test chart are determined according to the lengths of the accumulation times for the respective test patterns.
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Citations
18 Claims
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1. An image forming apparatus comprising:
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an image forming station configured to form an image on a sheet; conveyance rollers configured to convey the sheet on which the image is formed; a sensor configured to measure, based on an accumulation time, reflected light from a measurement image that is formed on a sheet conveyed by the conveyance rollers; and a processor configured to cause execution of tasks including; an image forming task that controls the image forming stations to form a plurality of measurement images on a sheet, wherein the plurality of measurement images includes a first measurement image and a second measurement image, and a measurement task that controls the sensor to measure the first measurement image based on a first accumulation time, and measure the second measurement image based on a second accumulation time, wherein the second accumulation time is longer than the first accumulation time, wherein the conveyance rollers are configured to reverse the conveyance direction of the sheet, wherein the processor is further configured to execute the measurement task after reversal of the conveyance direction of the sheet on which the plurality of measurement images is formed, and wherein a length of the first measurement image in a conveyance direction in which the conveyance rollers convey the sheet is shorter than a length of the second measurement image in the conveyance direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An image forming apparatus comprising:
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an image forming station configured to form an image on a sheet; conveyance rollers configured to convey the sheet on which the image is formed; a sensor configured to measure, based on an accumulation time, reflected light from a measurement image that is formed on a sheet conveyed by the conveyance rollers; and a processor configured to; control the image forming stations to form a plurality of measurement images on a test sheet, the plurality of measurement images includes a first measurement image and a second measurement image, control the conveyance rollers to convey the test sheet to the sensor, execute a first scan in which the sensor measures reflected light from the plurality of measurement images, and control the conveyance rollers to convey the test sheet to the sensor again, and configured to execute a second scan in which the sensor measures reflected light from the plurality of measurement images; wherein the processor determines a first accumulation time for the first measurement image in the second scan based on a measurement result of the first measurement image in the first scan, wherein the processor determines a second accumulation time for the second measurement image in the second scan based on a measurement result of the second measurement image in the first scan, wherein the sensor measures, based on a first predetermined accumulation time, reflected light from the first measurement image in the first scan, wherein the sensor measures, based on a second predetermined accumulation time, reflected light from the second measurement image in the first scan, wherein the second predetermined accumulation time is longer than the first predetermined accumulation time, and wherein a length of the first measurement image in a conveyance direction in which the conveyance rollers convey the test sheet is shorter than a length of the second measurement image in the conveyance direction. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification