Patent ID: 7547154

Claim:
A sheet material cutting unit comprising: a fixed blade; a movable blade mounted to undergo reciprocation with respect to the fixed blade between a first direction toward the fixed blade for cutting a sheet material and a second direction away from the fixed blade, the fixed blade and the movable blade being disposed opposite to each other with a sheet material transfer path therebetween; a movable blade holder integrally connected to an upper surface of the movable blade for reciprocation therewith; sheet material retaining means for retaining the sheet material on the sheet material transfer path during cutting of the sheet material, the sheet material retaining means comprising a fixed sheet material holding portion and a movable sheet material holding portion disposed opposite to the fixed sheet material holding portion with the sheet material transfer path therebetween, the movable sheet material holding portion being mounted on the movable blade holder for reciprocation therewith; transmitting means for transmitting reciprocal movement of the movable blade to the movable sheet material holding portion for maintaining the sheet material in a sandwiched state between the movable sheet material holding portion and the fixed sheet material holding portion during cutting of the sheet material, and for releasing the sheet material from the sandwiched state when the movable blade undergoes reciprocal movement in the second direction, the transmitting means comprising a notch portion formed in the movable blade holder, a biasing member disposed in the notch portion, and a protrusion of the movable sheet material holding portion extending into the notch portion and contacting the biasing member so that during movement of the movable blade in the first direction toward the fixed blade, the movement of the movable blade is transmitted to the movable sheet material holding portion; and a cover member covering the movable blade, the movable blade holder, and the movable sheet material holding portion, the cover member having side wall portions on opposite sides thereof for guiding the movable blade, the movable blade holder, and the movable sheet material holding portion during reciprocation thereof.