Apparatus for holding a receiver sheet in a video printer

A color video printer for producing a full colored image on a dye-absorbing receiver sheet by thermally transferring three different colored dyes applied to a ribbon in response to video signals, comprising:

• a supply means (102) for supplying said receiver sheet;
• a discharge means (104) for discharging said receiver sheet;
• a platen drum (20) with two ends having central shafts (21) and made so as to rotate only in one direction, said receiver sheet being fixedly supported upon the peripheral surface of said platen drum;
• a pair of holder members (60) respectively mounted on both ends of said platen drum so as to be pivotally moved about said central shafts (21);
• a pair of holders (61) each attached to said pair of holder members (60) for clamping the leading end of said receiver sheet to the peripheral surface of said platen drum;
• a head member (40) having a first cam follower (41) at one end and a thermal print head at the other end for thermally transferring said dyes of said ribbon to said receiver sheet;
• a pair of link structures (50, 70, 80, 90) with a second cam follower (82) for operating said pair of holder members (60) so as to cause said pair of holders (61) to temporarily protrude from the peripheral surface of said platen drum to receive said leading end of said receiver sheet;
• and
• a cam gear (30) with a first cam groove (31) engaged by said first cam follower (41) of said head member and a second groove (32) engagedly said second cam follower (82) of said pair of link structures for respectively actuating said head member and said holder members,
• wherein said pair of holder members (60) are resiliently supported by means of a pair of springs (66) so as to cause said pair of holders (61) to normally press said peripheral surface of said platen drum near said both ends thereof, said pair of link structures (50, 70, 80, 90) are so made as to temporarily push said pair of holder members (60) by rotating said cam gear (30), so that, when starting supply of said receiver sheet, said pair of holders (61) protrude from said peripheral surface of said platen drum to hold and clamp said leading end of said receiver sheet to said peripheral surface, and when said platen drum starts a third rotation for the last third dye to be transferred to said receiver sheet to which two of said three different colored dyes of Y, M and C have been sequentially transferred one by one at each rotation of said platen drum, said leading end of said receiver sheet is released from said pair of holders (61) so as to move towards said discharge means (104), and
• further wherein said pair of link structures comprise a pair of sliders (50) each with a guide slot (51) for making a straight motion, said guide slot having a sloped portion and horizontal portion, first lever (80) with said second cam follower (82) for moving said pair of sliders (50) forwards and backwards within a given limit according to the rotation of said cam gear (30), a pair of second levers (90) each with a hinge (91) at one end and a guide pin (92) at the other end thereof, said pair of second levers being pivoted on said hinges, and a pair of third levers (70) for pushing said pair of holder members (60) by pivotal movement so as to cause said pair of holders (61) to protrude from said peripheral surface of said platen drum (20), said pair of third levers being pivoted by said second pair of levers when said pair of sliders move to the forward limit by pivotal movement of said first lever.