Image reading apparatus and image forming apparatus

An image reading apparatus comprising:

• a conveyance unit configured to convey a sheet;
• a reading unit configured to read an image of the sheet being conveyed by the conveyance unit to obtain image data;
• a white reference member which is to be read by the reading unit;
• and
• one or more processors configured to perform operations including:
• receiving an instruction to start a reading job to read, by the reading unit, the image of the sheet conveyed by the conveyance unit,
• generating a shading correction value to be used for shading correction based on a result of the reading unit reading the white reference member in the reading job, and
• executing the shading correction on the image data which is obtained in the reading job, using the shading correction value,
• wherein a first period is a period from a first timing when the instruction is received to a second timing which is a timing after the first timing in the reading job and the reading unit is configured to read the white reference member with the first time interval in the first period in the reading job, and
• wherein a second time interval is longer than the first time interval and the reading unit is configured to read the white reference member with the second time interval after the second timing in the reading job.

An image reading apparatus comprising:

• a conveyance unit configured to convey a sheet;
• a reading unit configured to read an image of the sheet being conveyed by the conveyance unit to obtain image data;
• a white reference member which is to be read by the reading unit;
• and
• one or more processors configured to perform operations including:
• receiving an instruction to start a reading job to read, by the reading unit, the image of the sheet conveyed by the conveyance unit,
• generating a shading correction value to be used for shading correction based on a result of the reading unit reading the white reference member in the reading job, and
• executing the shading correction on the image data which is obtained in the reading job, using the shading correction value,
• wherein, in a case where the number of times in which processes of reading the white reference member has been performed in the reading job is less than a predetermined number of times, the reading unit reads the white reference member every time the reading unit reads a first number of sheets in the reading job, and
• wherein, in a case where the number of times in which processes of reading the white reference member has been performed in the reading job is more than the predetermined number of times, the reading unit reads the white reference member every time the reading unit reads a second number of sheets which is more than the first number of sheets in the reading job.

An image reading apparatus comprising:

• a conveyance unit configured to convey a sheet;
• a reading unit configured to read an image of the sheet being conveyed by the conveyance unit to obtain image data;
• a white reference member which is to be read by the reading unit;
• and
• one or more processors configured to perform operations including:
• receiving an instruction to start a reading job to read, by the reading unit, the image of the sheet conveyed by the conveyance unit,
• generating a shading correction value to be used for shading correction based on a result of the reading unit reading the white reference member in the reading job, and
• executing the shading correction on the image data which is obtained in the reading job, using the shading correction value,
• wherein a first period is a period from a first timing when the instruction is received to a second timing which is a timing after the first timing in the reading job and the reading unit reads the white reference member every time the reading unit reads a first number of sheets in the first period in the reading job, and
• wherein a second number of sheets is more than the first number of sheets and the reading unit reads the white reference member every time the reading unit reads the second number of sheets after the second timing in the reading job.