Image forming apparatus and control method of an image forming apparatus having an ordinary reading mode and a quiet reading mode

An image forming apparatus comprising:

• a printing section which prints on paper while transporting the paper;
• and
• a document reading section, including a document transport portion which automatically transports, sheet by sheet, a document placed thereon,
• the document reading section being operable
• in an ordinary reading mode in which the document reading section reads the document at a previously determined ordinary speed and
• in a quiet reading mode in which the document reading section reads the document at a quiet speed lower than the ordinary speed,
• in a copying job in which the printing section prints based on image data obtained by reading the document transported by the document transport portion, the document reading section
• generating the image data by reading the document in the quiet reading mode until the printing section starts to print based on the image data obtained by document reading and
• generating the image data by reading the document in the ordinary reading mode after the printing section starts to print based on the image data obtained by document reading.