Tube pump, liquid ejecting apparatus, and method of driving tube pump

A tube pump comprising:

• a portion of a tube made of a flexible material;
• a pressing member capable of generating a negative pressure in the portion of tube by sequentially pressing the portion of the tube as the pressing member moves from an upstream portion of the tube to a downstream portion of the tube during a pump operating process;
• a rotating member which includes a cam surface which the pressing member comes into sliding contact with when the pressing member moves between a pump operating position where a negative pressure is generated in the upstream portion of the tube and a pump non-operating position where a negative pressure is not generated in the upstream portion of the tube;
• and
• a rack member corresponding to the cam surface which includes a plurality of teeth,
• wherein the pressing member is provided with a pinion member which is capable of engaging with the rack member, when the pressing member rotatably moves between the pump non-operating position and the pump operating position.