Sheet conveyance apparatus, image reading apparatus and image forming apparatus

An image reading apparatus comprising:

• a supporting portion configured to support a sheet;
• a detection unit configured to detect a sheet supported on the supporting portion;
• a feeding unit disposed above the supporting portion and configured to feed a sheet supported on the supporting portion;
• a lifting unit configured to lift and lower the supporting portion between a first position to feed a sheet by the feeding unit and a second position below the first position;
• a control unit configured to control lifting and lowering of the supporting portion by the lifting unit;
• and
• a reading portion configured to read image information from a sheet fed by the feeding unit,
• wherein the control unit is capable of selectively executing a first mode and a second mode, the first mode being a mode in which a plurality of sheets supported on the supporting portion and having different sizes including a non-standard size are read by the reading portion, the second mode being a mode in which a plurality of sheets supported on the supporting portion and having different sizes including only standard sizes are read by the reading portion,
• wherein if the detection unit detects a sheet in a state where the supporting portion is located at the second position and the first mode is selected, the control unit waits for an instruction to start sheet reading without causing the lifting unit to lift the supporting portion to the first position, and causes the lifting unit to lift the supporting portion to the first position in response to the instruction to start sheet reading, and
• wherein if the detection unit detects a sheet in a state where the supporting portion is located at the second position and the second mode is selected, the control unit causes the lifting unit to lift the supporting portion to the first position and waits for the instruction to start sheet reading.

An image forming apparatus comprising:

• a supporting portion configured to support a sheet;
• a detection unit configured to detect a sheet supported on the supporting portion;
• a feeding unit disposed above the supporting portion and configured to feed a sheet supported on the supporting portion;
• a lifting unit configured to lift and lower the supporting portion between a first position to feed a sheet by the feeding unit and a second position below the first position;
• a control unit configured to control lifting and lowering of the supporting portion by the lifting unit;
• a reading portion configured to read image information from a sheet fed by the feeding unit;
• and
• an image forming portion configured to form an image on a recording material based on the image information read by the reading portion,
• wherein the control unit is capable of selectively executing a first mode and a second mode, the first mode being a mode in which a plurality of sheets supported on the supporting portion and having different sizes including a non-standard size are read by the reading portion, the second mode being a mode in which a plurality of sheets supported on the supporting portion and having different sizes including only standard sizes are read by the reading portion,
• wherein if the detection unit detects a sheet in a state where the supporting portion is located at the second position and the first mode is selected, the control unit waits for an instruction to start sheet reading without causing the lifting unit to lift the supporting portion to the first position, and causes the lifting unit to lift the supporting portion to the first position in response to the instruction to start sheet reading, and
• wherein if the detection unit detects a sheet in a state where the supporting portion is located at the second position and the second mode is selected, the control unit causes the lifting unit to lift the supporting portion to the first position and waits for the instruction to start sheet reading.