BACKGROUND

Field

The present disclosure relates to an image forming apparatus and a method of controlling the image forming apparatus.

Description of the Related Art

In calibration discussed in Japanese Patent Application Laid-Open No. 2009-239357, a document is read by a front-surface reading unit and a rear-surface reading unit, and in a case where color values acquired by the respective units are different from each other, the difference is corrected. According to Japanese Patent Application Laid-Open No. 2009-239357, a chart document to be used for correction of the difference is output by a printer, the output chart document is read by the front-surface reading unit and the rear-surface reading unit to calculate the difference, and calculates a correction value.

SUMMARY

It has now been determined that a rear-surface reading unit, low in use frequency, may have a reduced performance for cost reduction. More specifically, a reading unit having resolution of 600 dots per inch (dpi) is used for a front surface reading unit, whereas a reading unit having resolution of 300 dpi is used for a rear surface reading unit.

Meanwhile, in some cases, image printing resolution of an image forming apparatus is set higher than reading resolution of the reading units, for high definition image printing.

When an image processing apparatus including the above-described reading units reads a chart document of, for example, 190 lines per inch (lpi), moiré occurs on the image read by the reading unit having the reading resolution half the value of which is lower than the resolution of the chart document.

Consequently, if the setting of resolution of an image to be printed in printing of a chart document is used unchanged, the difference between the color value by the front-surface reading unit and the color value by the rear-surface reading unit cannot be accurately determined, which may deteriorate correction accuracy.

In consideration of the above, the present disclosure features reducing or preventing deterioration of correction accuracy in an image forming apparatus that reads a chart document by a plurality of reading units and corrects a difference between acquired color values.

According to an aspect of the present disclosure, an image forming apparatus includes a first reading unit configured to read a first image on a first surface of a document, a second reading unit configured to read a second image on a second surface of the document, the second surface different from the first surface, a printing unit configured to print a third image on a sheet, and a setting unit configured to set resolution of the third image printed by the printing unit, wherein the printing unit prints the third image on the sheet with the resolution set by the setting unit, and wherein the printing unit prints a fourth image with resolution lower than or equal to a threshold, without using the set resolution, the fourth image used for correction of at least a color value obtained by reading the second image using the second reading unit.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

