Clamping device and printer

Abstract

A sheet 3 is caught between a clamper 15 and a platen drum 10 at its sheet front end portion. The clamper 15 is provided with a pressing member 32 with elasticity, and the pressing member 32 has two projections 32 b. During conveyance, a pressing surface 32 a tightly comes into contact with the front end portion of the sheet 3, while each projection 32 b is elastically deformed and compressed. When correcting skew of the sheet 3, the clamper 15 is turned, while only the projections 32 b press the front end portion of the sheet 3.

1 . A clamping device comprising:
 a clamper having a pressing member with elasticity, for catching a part of a lenticular sheet between said pressing member and a support member for supporting at least a part of said lenticular sheet;   a clamper shifting mechanism for shifting said damper among a retracted position, a first catching position, and a second catching position, said pressing member being away from said support member in said retracted position, said pressing member pressing said part of said lenticular sheet so as to prevent a slip of said lenticular sheet from said pressing member and said support member in said first catching position, said pressing member pressing said part of said lenticular sheet so as to prevent a slip of said lenticular sheet from said pressing member and allow a slip of said lenticular sheet from said support member in said second catching position;   a clamper turning mechanism for turning said clamper around a turning axis orthogonal to said lenticular sheet; and   a controller, wherein
 when turning said lenticular sheet being caught, said controller controls said clamper shifting mechanism and said clamper turning mechanism so as to set said clamper in said second catching position and turn said clamper; 
 when fixing said lenticular sheet on said support member, said controller controls said clamper shifting mechanism so as to set said clamper in said first catching position. 
   
     
     
         2 . The clamping device as recited in  claim 1 , wherein
 said pressing member has a plurality of projections formed in a pressing surface faced to said support member;   said first catching position denotes a position in which said pressing surface is pressed against said part of said lenticular sheet while compressing each of said projections, to catch said part of said lenticular sheet between said pressing surface and said support member; and   said second catching position denotes a position in which each of said projections is pressed against said part of said lenticular sheet with a compression value of each of said projections lower than that of said first catching position, to catch said part of said lenticular sheet between each of said projections and said support member.   
     
     
         3 . The clamping device as recited in  claim 2 , wherein a size of said projection is in accordance with a distance from said turning axis, and in said second catching position, an area at which said projection contacts with said lenticular sheet differs in accordance with said distance from said turning axis. 
     
     
         4 . The clamping device as recited in  claim 2 , wherein out of a surface area of said support member, at least an area faced to said projection plus a movable area of said projection by said clamper turning mechanism are allocated to a non-formation area, and a remaining area is allocated to a formation area, and an elastic layer having elasticity is formed in said formation area to make a coefficient of friction in said non-formation area smaller than that in said formation area. 
     
     
         5 . The clamping device as recited in  claim 4 , wherein said formation area includes a portion of said support member faced to said pressing surface, such that said part of said lenticular sheet is caught between said pressing surface and said elastic layer when said damper is in said first catching position. 
     
     
         6 . A printer having a printing section that conveys in a sub scan direction a lenticular sheet having a plurality of lenses formed in a front surface of said lenticular sheet, and sequentially prints on a back surface of said lenticular sheet a plurality of stripe images parallel to a main scan direction orthogonal to said sub scan direction, said printer comprising:
 a platen for supporting said lenticular sheet and moving said lenticular sheet in said sub scan direction;   a clamper having a pressing member with elasticity, for pressing a sheet end portion of said lenticular sheet against said platen to catch said sheet end portion between said clamper itself and said platen;   a clamper shifting mechanism for shifting said clamper among a retracted position, a first catching position, and a second catching position, said pressing member being away from said platen in said retracted position, said pressing member pressing said sheet end portion so as to prevent a slip of said lenticular sheet from said pressing member and said platen in said first catching position, said pressing member pressing said sheet end portion so as to prevent a slip of said lenticular sheet from said pressing member and allow a slip of said lenticular sheet from said platen in said second catching position;   a skew detection section for detecting skew of said lenticular sheet;   a damper turning mechanism for turning said clamper around a turning axis orthogonal to said lenticular sheet; and   a controller, wherein
 when correcting said skew of said lenticular sheet with respect to said main scan direction, said controller controls said damper shifting mechanism and said clamper turning mechanism to set said clamper in said second catching position and turn said clamper based on a detection result of said skew detection section; and 
 when conveying said lenticular sheet in said sub scan direction, said controller controls said clamper shifting mechanism to set said clamper in said first catching position while said platen is moved in said sub scan direction. 
   
     
     
         7 . The printer as recited in  claim 6 , wherein
 said pressing member has a plurality of projections formed in a pressing surface faced to said platen;   said first catching position denotes a position in which said pressing surface is pressed against said sheet end portion while compressing each of said projections, to catch said sheet end portion between said pressing surface and said platen: and   said second catching position denotes a position in which each of said projections is pressed against said sheet end portion with a compression value of each of said projections lower than that of said first catching position, to catch said sheet end portion between each of said projections and said platen.   
     
     
         8 . The printer as recited in  claim 7 , wherein a size of said projection is in accordance with a distance from said turning axis, and in said second catching position, an area at which said projection contacts with said sheet end portion differs in accordance with said distance from said turning axis. 
     
     
         9 . The printer as recited in  claim 7 , wherein out of a surface area of said platen, at least an area faced to said projection plus a movable area of said projection by said clamper turning mechanism are allocated to a non-formation area, and a remaining area is allocated to a formation area, and an elastic layer having elasticity is formed in said formation area, and a coefficient of friction is smaller in said non-formation area than that in said formation area. 
     
     
         10 . The printer as recited in  claim 9 , wherein said formation area includes a portion of said platen faced to said pressing surface, such that said sheet end portion is caught between said pressing surface and said elastic layer when said clamper is in said first catching position. 
     
     
         11 . The printer as recited in  claim 6 , wherein said platen comprises a rotatable platen drum on which said lenticular sheet is wound. 
     
     
         12 . The printer as recited in  claim 6 , wherein a sheet front end portion of said lenticular sheet is caught between said clamper and said platen. 
     
     
         13 . The clamping device as recited in  claim 3 , wherein out of a surface area of said support member, at least an area faced to said projection plus a movable area of said projection by said clamper turning mechanism are allocated to a non-formation area, and a remaining area is allocated to a formation area, and an elastic layer having elasticity is formed in said formation area to make a coefficient of friction in said non-formation area smaller than that in said formation area. 
     
     
         14 . The printer as recited in  claim 8 , wherein out of a surface area of said platen, at least an area faced to said projection plus a movable area of said projection by said damper turning mechanism are allocated to a non-formation area, and a remaining area is allocated to a formation area, and an elastic layer having elasticity is formed in said formation area, and a coefficient of friction is smaller in said non-formation area than that in said formation area. 
     
     
         15 . The printer as recited in  claim 7 . wherein said platen comprises a rotatable platen drum on which said lenticular sheet is wound. 
     
     
         16 . The printer as recited in  claim 8 , wherein said platen comprises a rotatable platen drum on which said lenticular sheet is wound. 
     
     
         17 . The printer as recited in  claim 9 , wherein said platen comprises a rotatable platen drum on which said lenticular sheet is wound. 
     
     
         18 . The printer as recited in  claim 10 , wherein said platen comprises a rotatable platen drum on which said lenticular sheet is wound. 
     
     
         19 . The printer as recited in  claim 2 , wherein a sheet front end portion of said lenticular sheet is caught between said clamper and said platen. 
     
     
         20 . The printer as recited in  claim 3 , wherein a sheet front end portion of said lenticular sheet is caught between said clamper and said platen.