Paper feeder and image forming apparatus

A paper feeder comprising:

• a tray in which a sheet can be placed;
• a delivery roller that delivers the sheet placed in the tray;
• a paper feed roller that feeds the delivered sheet to a conveyance path;
• a guide member that guides the delivered sheet from the tray toward the paper feed roller and is provided to be inclined upward toward the paper feed roller;
• a lifting/lowering mechanism capable of changing a height of the tray;
• and
• a controller that executes paper feed processing to feed the delivered sheet from the tray to the conveyance path by causing the paper feed roller to rotate, wherein
• the controller has:
• a setting device that accepts job settings including settings related to plural types of sheets, the plural types of sheets including a first sheet and a second sheet that is thicker than the first sheet;
• and a lifting/lowering controller that controls the lifting/lowering mechanism such that, in the case where the second sheet is set, before initiation of the paper feed processing, a height of the tray with respect to the guide member becomes higher by a first predetermined magnitude than that in the case where the first sheet is set.