Patent ID: 7997197

Claim:
In combination with a printing machine or unit having a roll rotatable about an axis having a radially outwardly directed roll surface, an ink cartridge comprising: a housing having a movable side wall, a fixed side wall, and a pair of end walls bridging the fixed and movable side walls and defining therewith a downwardly open mouth juxtaposed with the roll surface, the movable side wall being shiftable between an outer position defining with the fixed side wall and end walls a first volume and an inner position defining with the fixed side wall and end walls a second volume; respective movable and fixed doctor blades supported on the housing flanking the mouth and having outer edges resiliently engageable at the mouth with the surface, whereby a body of ink can be held between the blades and engage the surface between the outer edges of the blades, the movable doctor blade being attached to the movable side wall and shiftable therewith on the housing between an open position with its outer edge spaced from the outer edge of the fixed doctor blade and a closed position with the outer edges engaging each other and the blades closing the mouth; and means connected to the movable side wall and to the movable doctor blade for shifting the movable doctor blade between the open position and the closed position and for generally simultaneously shifting the movable side wall between the inner position and the outer position by pivoting an upper portion of the movable wall outward away from the fixed wall while pivoting a lower portion of the movable side wall inward toward the fixed side wall such that, as the movable doctor blade moves, a depth of the body of ink in the cartridge remains generally constant.