Receiver clamping arrangement for thermal printers

Claim 1

In a thermal printer apparatus in which dye is transferred from a dye-carrier to a receiver sheet by heat applied from a print head which forms a nip by pressing the carrier against the receiver sheet, the receiver sheet being mounted on a rotatable drum having a platen surface and end surfaces and wherein said drum is rotatable in a first direction during image transfer and in a second direction for sheet ejection, sheet clamping apparatus comprising: (a) said drum defining a recess extending across its width; (b) a clamp mechanism including a pivotably mounted member mounted on an end surface of said drum, a clamping lever disposed in said recess and connected to said pivotably mounted member, and spring means fixed to said drum and said pivotably mounted member to urge said pivotably mounted member to move to a position which causes said clamping lever to move from an open sheet receiving or ejecting position to a closed sheet clamping position; (c) spaced first and fixed spaced cam members each having interior and exterior camming surfaces; and (d) a link pivotably mounted on said end surface and including a portion engageable with said pivotably mounted member and a follower engageable with said interior and exterior camming surfaces of said cam member so that as said drum rotates in said first direction said follower engages said interior camming surfaces and said lever is in the closed sheet clamping position and when said drum rotates in said second direction said follower moves between said cam members onto the exterior camming surface of one of such cam member until it reaches a position where said link moves said pivotably mounted member to cause said clamping lever to move to the open position for sheet ejection.