Technique for measuring color of measurement image

摘要

A test chart on which measurement images are formed is conveyed in one direction. When the measurement images pass a color sensor, they undergo pre-scanning. A color sensor accumulation time is determined for each measurement image according to the pre-scanning. The test chart is subsequently conveyed in the one direction, whereupon the conveyance direction is changed. In this way, after the color sensor has completed pre-scanning for all of the measurement images, the test chart is once again conveyed toward the color sensor. When the test chart passes the color sensor again, main scanning of the measurement images is executed.

主权项

1. An image forming apparatus comprising:
an image forming unit configured to form a measurement image on a sheet; a conveyance unit configured to convey the sheet; a measurement unit configured to measure the measurement image by accumulating reflected light from the measurement image on the sheet conveyed by the conveyance unit; a control unit configured to control the image forming unit to form the measurement image on the sheet, control the conveyance unit to convey the sheet on which the measurement image is formed toward the measurement unit, control the measurement unit to execute a first scan during which the measurement unit measures the measurement image formed on the sheet, control the conveyance unit to convey the sheet on which the measurement image is formed toward the measurement unit again, and control the measurement unit to execute a second scan during which the measurement unit measures the measurement image formed on the sheet; and a determination unit configured, based on a measurement result of the measurement unit in the first scan, to determine a reflected light accumulation time during which the measurement unit accumulates reflected light from the measurement image in the second scan, wherein the control unit executes the first scan using one reflected light accumulation time among a plurality of different reflected light accumulation times provided in advance, and the determination unit estimates another measurement result corresponding to another reflected light accumulation time based on a linearity relation between the reflected light accumulation time and the measurement result, the predetermined reflected light accumulation time, and the measurement result obtained using the predetermined reflected light accumulation time in the first scan, and identifies a highest measurement result in a range in which saturation does not occur from among the plurality of measurement results, and determine the reflected light accumulation time corresponding to the identified measurement result to be the reflected light accumulation time for the second scan, wherein each of a plurality of measurement results corresponds to a different one of the reflected light accumulation time.