Impact line printer

Claim 2

In a printer for printing characters on a flexible sheet having means for intermittently advancing said flexible sheet as characters are printed thereon, each of said characters being formed by printing a plurality of small dots at desired intersections of a discrete number of columns and rows, the improvement comprising: a frame; a plurality of hammers each carrying a striking means for printing a dot and aligned with each other and mounted on a hammer support; means movably securing said hammer support to said frame with said hammers adjacent said flexible sheet; a stationary platen positioned opposite said hammers and on the opposite side of said flexible sheet; stepping means connected to said hammer support to step said support and hammers a discrete number of step positions across said flexible sheet for aligning each hammer with one of said columns, said discrete number of step positions being equal to the number of columns used to form one of said characters; a plurality of electromagnets immovably secured to said frame, each positioned to actuate, when energized, only a respective one of said hammers when said respective hammer is in any of said step positions; and means for selectively energizing said electromagnets.

Claim 3

The combination set forth in claim 1, wherein said stepping means is reversible to step said support and hammers a discrete number of step positions back and forth across said flexible sheet.

Claim 4

The combination set forth in claim 1, wherein said stepping means comprises a rotatable stepping motor having one end of a semi-flexible strap secured to the motor shaft and another end secured to said hammer support.

Claim 5

The combination set forth in claim 1, wherein said hammers are drawn toward said electromagnets and are released to strike said sheet upon energization and de-energization respectively of said electromagnets.

Claim 6

The combination set forth in claim 1, including a plurality of two-dimensionally, semi-flexible straps secured to said frame and to said hammer support, each of said plurality of straps positioned to flex and to permit horizontal movement of said hammer support and to prevent vertical movement of said hammer support.

Claim 7

A printer for printing characters on a flexible sheet having sheet stepping means for vertically advancing said flexible sheet as characters are formed thereon, each of said characters being formed by printing a plurality of small dots at desired intersections of a discrete number of columns and rows, comprising: a frame; a plurality of hammers each carrying a striking means for printing a dot and aligned with each other and mounted adjacent said sheet on a hammer support; a stationary platen positioned opposite said hammers and on the opposite side of said flexible sheet; each of said hammers, when actuated, forming a dot on said sheet by striking said sheet; means movably securing said hammer support to said frame, said support being horizontally movable with respect to said sheet; hammer stepping means connected to said hammer support for horizontally stepping said support in one direction to a predetermined number of step positions for aligning each hammer with one of said columns, said discrete number of step positions being equal to the number of columns used to form one of said characters; said hammer stepping means being reversible when said sheet stepping means has vertically advanced said sheet to step said hammer support in an opposite direction to said predetermined number of step positions; a plurality of electromagnets immovably secured to said frame, each positioned to actuate, when energized, only a respective one of said hammers when said respective hammer is in any of said step positions; and means for selectively energizing said electromagnets.

Claim 8

A printer for printing characters on a flexible sheet having sheet stepping means for vertically advancing said flexible sheet as characters are formed thereon, each of said characters being formed by printing a plurality of small dots at desired intersections of a discrete number of columns and rows, comprising: a frame; a plurality of hammers each carrying a striking means for printing a dot and aligned with each other and mounted adjacent said sheet on a hammer support; a stationary platen positioned opposite said hammers and on the opposite side of said flexible sheet; each of said hammers, when actuated, forming a dot on said sheet by striking said sheet; means movably securing said hammer support to said frame, said support being horizontally movable with respect to said sheet; hammer stepping means connected to said hammer support for horizontally stepping said support in one direction to a predetermined number of step positions for aligning each hammer with one of said columns, said discrete number of step positions being equal to the number of columns used to form one of said characters; said hammer stepping means being reversible when said sheet stepping means has vertically advanced said sheet to step said hammer support in an opposite direction to said predetermined number of step positions; a plurality of electromagnets immovably secured to said frame, each positioned to actuate, when energized, only a respective one of said hammers when said respective hammer is in any of said step positions; and means for selectively energizing said electromagnets.

Claim 9

The combination set forth in claim 6, wherein said stepping means comprises a rotatable stepping motor having one end of a semi-flexible strap secured to the motor shaft and another end secured to said hammer support.

Claim 10

The combination set forth in claim 6, wherein said hammers are drawn toward said electromagnets and are released to strike said sheet upon energization and de-energization respectively of said electromagnets.

Claim 11

The combination set forth in claim 6, wherein the striking means of each of said hammers comprises an edge extending in a predetermined direction, said hammers positioned on one side of said flexible sheet; said stationary platen having a striking surface comprising an edge extending perpendicular to said predetermined direction; said hammer striking surface and said platen striking surface positioned relative to each other to form a dot on said sheet at an intersection of their respective striking surfaces when they are forced together with said sheet therebetween.

Claim 12

The combination set forth in claim 9, wherein the striking surfaces of said hammers are vertically extending rectilinear edges.

Claim 13

The combination set forth in claim 10, wherein the striking surface of said platen comprises a horizontally extending rectilinear edge.