Patent ID: 6224806
Filing Date: 2001-05-01
Classification: B29C,B41J

Abstract:
A method of molding a cavity plate of an ink jet printer head, said cavity plate being adapted to be attached to a piezoelectric element member and having walls prescribing a plurality of ink storing chambers and a plurality of ink discharge holes, said method comprising the processes of(I) assembling a plurality of pin members to a corniform block member as a mold,said corniform block member comprising (i) a plurality of corniform convex portions to mold the ink storing chambers, each having an opening portion on a side of an attachment surface of said cavity plate to be attached to the piezoelectric element member, and (ii) a plurality of corniform concave portions to mold partition walls of said cavity plate for partitioning each of the ink storing chambers, said corniform convex portions and said corniform concave portions being alternatively disposed,said pin members to mold the ink discharge holes, which are continuous to the ink storing chambers such that the ink discharge holes have straight tubular portions respectively from the ink storing chambers to ink discharge tip portions at an ink discharge surface of said cavity plate on an opposite side of the attachment surface, comprising:(A) U shaped column portions, a cross section of each of which is in a U letter shape, to mold connection portions between the ink storing chambers and the straight tubular portions respectively, each of said U shaped column portions comprising (i) a half-cylindrical portion a cross section of which is in a half-circle shape and (ii) a prism portion a cross section of which is in a rectangular shape, at least whose length of one side is equal to a diameter of said half-cylindrical portion, said half-cylindrical portion and said prism portion being integrally formed; and(B) cylindrical portions to mold the straight tubular portions respectively, said U shaped column portions and said cylindrical portions being respectively formed continuously and integrally,said prism portion having an edge surface which contact with an edge surface of respective one of said corniform convex portions at a position corresponding to the connection portions in a condition where said pin members are assembled to said corniform block member, and(II) injection molding a material of said cavity plate into said assembled mold.