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US 6,172,741 B2Granted
Vacuum surface for wet dye hard copy apparatus
AssigneeHewlett-Packard Company
InventorsGeoff Wotton, Angela Chen, Steve O. Rasmussen, John D Rhodes
Life of this patent
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Abstract
A platen surface structure construct, particularly useful in a hard copy apparatus for a vacuum holddown, is configured by dimensioning print media platen surface structure channels and ports in order to ensure print media leading edge and trailing edge holddown. Moreover, the vacuum is distributed across the platen surface in accordance with predetermined dye flow characteristics based upon known dye composition and known print medium composition and such that print artifacts are not created by vacuum pulling wet dye through the capillaries of the medium.
Claims20
A platen surface structure for a vacuum holddown of a hard copy means for printing with wet dye on print media, the hard copy means having a vacuum generating means for producing a predetermined vacuum force, the structure comprising:
- the vacuum holddown having a platen;
- the platen having a first surface for receiving print media thereon, the first surface having predetermined width dimension in a predetermined first axis of symmetry, and the first surface having a plurality of vacuum channels distributively arranged in parallel wherein each of the channels is substantially parallel to the first axis of symmetry, adjacent channels having substantially identical predetermined channel shape and channel dimensions;
- each of the channels has at least one vacuum port associated therewith, fluidically coupling each of the channels, respectively, to the vacuum generating means, each of the channels are separated from adjacent channels thereto by platen surface structure ribs, wherein each of the ribs is substantially parallel to the first axis of symmetry, such that the ribs form a print media receiving surface;
- and
- the ribs having predetermined rib shape and rib dimensions and the channels have the predetermined channel shape and channel dimensions such that the vacuum force is distributed through the channels and imparted to regions of print media received on the ribs and spanning the channels to hold the print media to the platen first surface, wherein the first surface provides leading and trailing edge holddown on the platen.
2 more elements
A vacuum platen device for an ink-jet apparatus having a means for producing a vacuum Fv, the device comprising:
- a platen having an outer platen surface and an inner platen surface wherein print media sheets are sequentially delivered to the outer platen surface from a predetermined media delivery direction, the platen having a first axis perpendicular to the predetermined media delivery direction and a second axis parallel to the predetermined media delivery direction;
- the outer platen surface having an outer platen surface structure having a repeated pattern of vacuum channels in the outer platen surface wherein each of the channels has a channel major axis substantially parallel to the first axis and a channel minor axis substantially parallel to the second axis;
- the outer platen surface structure having platen surface structure ribs, each of the ribs separating a pair of the vacuum channels, the ribs having a rib major axis substantially parallel to the first axis and a rib minor axis substantially parallel to the second axis;
- and
- each of the vacuum channels having a least one vacuum port from the outer platen surface to the inner platen surface, fluidically coupling each of the vacuum channels to the means for producing a vacuum, respectively, and wherein the ribs have a predetermined rib shape and rib dimensions and the channels have a predetermined channel shape and channel dimensions such that the vacuum force is distributed through the channels and imparted to regions of the print media received on the ribs and spanning the channels to hold the print media to the outer platen surface, and wherein the platen further provides print media leading edge and print media trailing edge holddown.
2 more elements
An ink-jet hard copy apparatus having a means for generating a predetermined vacuum force Fv, comprising:
- a housing;
- mounted to the housing, means for ink-jet printing;
- mounted to the housing, means for holding cut-sheet print media;
- mounted within the housing and associated with the means for holding cut-sheet print media, vacuum drum means for sequentially transporting individual sheets of print media from the means for holding to a printing station adjacent the means for ink-jet printing;
- and
- the vacuum drum means, having a predetermined longitudinal spin axis and a predetermined axial length and including an inner surface forming a vacuum chamber fluidically coupled to the means for generating a vacuum force, an outer surface positioned adjacently to the means for holding cut-sheet print media, forming a cylindrical platen for sequentially receiving individual sheets of media from the means for holding, the outer surface including a plurality of vacuum channels across the outer surface, each of the channels having at least one vacuum port extending from an interior of a respective channel to the inner surface such that the predetermined vacuum force is coupled to each of the channels and distributed thereby across the platen, each of the channels having a predetermined channel length parallel to the spin axis and a predetermined circumferential channel width wherein the channel length is approximately equal to or less than the predetermined axial length of the vacuum drum means and the circumferential channel width is less than a predetermined dimension wherein the vacuum force distributed by respective channels provides leading edge and trailing edge holddown of the print media.
3 more elements
A method for using a known vacuum force for holding print media during a wet dye printing operation, comprising the steps of:
- providing a platen having print media platen surface structure having vacuum channels oriented, shaped, and dimensioned across the platen in accordance with a predetermined geometry for ensuring leading edge and trailing edge holddown of the print media;
- delivering the print media to the platen;
- and
- holding the print media to the platen with the vacuum force distributed through the channels during printing, wherein the predetermined geometry is a function of dye flow characteristics based upon known dye composition and known print medium composition such that print artifacts are not created by the known vacuum force pulling wet dye through capillaries of the medium.
1 more element
Dependencies are inferred from the claim text.