US 4,843,338 A · Ink-set printhead-to-paper referencing system

Abstract

Several problems of alignment associated with ink-jet printers are alleviated by four aspects. In the first, a reverse bow (B) in the paper (12) is created for printing on single sheets of paper. The reverse bow, which in the transverse axis of the paper, forces the paper flat against the platen (14) by using the paper's own stiffness. In the second aspect, the paper and the carriage (30) are referenced to the same part (the carriage guide (10)). In this configuration, the paper is urged against the underside of the carriage guide off of drive rollers (18), through the reverse bow, and onto the platen, where it is printed. The carriage is referenced to the carriage guide through a slider bump by means of a carriage shaft and gravity. The carraige guide comprises stiff thin sheet metal, which is closely-toleranced and has well-controlled dimensions. Thus, this part is good to reference to, rather than molded-in parts, which are not stiff enough at the required thickness. Straightness is also difficult to achieve at the required thickness with plastic parts. In the third aspect, the platen is allowed to move substantially perpendicular to the plane of the paper to accommodate thicker print media. In the fourth aspect, the platen is maintained a minimum fixed distance from the carriage guide by bumps (38) to ensure that the paper is not pinched between the carriage guide and the platen.

Claims25

Dependent claims

An improved ink-jet printer including a print cartridge (28) having a printhead (34) thereon and secured in a carriage (30), said printer further including a carriage guide (10), a platen (14, for supporting a print medium (12) at least through a print zone (A), and means (15) for moving said print medium beneath said carriage guide and onto said platen, the improvement comprising:

(a) said carriage guide including means for creating a reverse bow (B) in said print medium, parallel to the direction of printing, which causes said print medium to lie substantially flat on said platen;
(b) said means for moving (15) and said carriage (30) having means (36,18) for referencing said carriage and said print medium to said carriage guide;
and
(c) said platen including means (39) for permitting said platen to move to accommodate varying thicknesses of said print medium.

1 more element

Dependencies are inferred from the claim text.

Ink-set printhead-to-paper referencing system

Life of this patent

Ink-set printhead-to-paper referencing system

Life of this patent

Abstract

Claims25