Controlling vacuum flow for ink-jet hard copy apparatus

A vacuum platen system for transporting print media through a printing zone, comprising:

• an ink-jet printer platen having channels and ports permitting airflow therethrough at predetermined positions of a surface thereof;
• a vacuum device associated with the platen and inducing the airflow;
• and
• a transport belt superjacent the surface, having an array of belt perforations such that the perforations through the belt have a diameter less than associated port diameters, said channels having a cross-dimension in the direction of travel of the belt thereacross that is less than or equal to a distance separating the belt perforations in the direction of travel of the belt.

A vacuum platen system for transporting print media through a printing zone, comprising:

• an ink-jet printer platen having channels and ports permitting airflow therethrough at predetermined positions of a surface thereof;
• a vacuum device associated with the platen and inducing the airflow;
• and
• a transport belt superjacent the surface, having an array of belt perforations such that the perforations through the belt have a diameter less than associated port diameters, wherein each of the vacuum ports is of a size and dimension large enough such that the ports do not clog with ink or paper dust and such that if one or more of said channels are partially open relatively low airflow is pulled through the open portion such that there is substantially no loss of vacuum pressure on sheet media edges superjacent the one or more channels.

A method for transporting print media across a vacuum platen associated with a vacuum inducing mechanism in a printing zone of an ink-jet hard copy apparatus, the method comprising:

• drawing by said vacuum inducing mechanism an airflow through a plurality of vacuum ports distributed across the platen;
• transporting ink-jet print media across the platen in a predetermined direction by a perforated belt associated by face-to-face contact relationship with the platen so as to restrict substantially only said airflow through said belt by a combined construct comprising the platen and the belt by providing a predetermined net porosity of said platen and said perforated belt in combination such that said airflow is a substantially uniform airflow established for holding an ink-jet print media on said belt;
• and
• fluidically coupling the vacuum ports to channels oriented across the platen substantially perpendicularly to the predetermined direction.

An ink-jet hard copy apparatus comprising:

• an ink-jet writing instrument associated with a printing zone within the apparatus;
• an endless loop vacuum belt system for transporting print media to and from the printing zone;
• and
• a vacuum platen system located proximate the printing zone, the vacuum platen system having a platen, having a plurality of vacuum ports therethrough, a vacuum chamber, and a vacuum device for maintaining a negative pressure within the chamber such that an airflow is established through the vacuum ports into the chamber, wherein the vacuum belt system has a belt having perforations, each of said perforations being of a smaller size than each of said ports such that a uniform vacuum holding pressure is exerted on a sheet of print media carried by the belt across the platen and the airflow superjacent the belt in the printing zone is less than an airflow that affects ink drop flight trajectories while a substantially uniform airflow is established for holding an ink-jet print media on said belt, wherein a pressure drop through the platen is approximately four percent of a pressure drop through the belt.

An ink-jet hard copy apparatus comprising:

• an ink-jet writing instrument associated with a printing zone within the apparatus;
• an endless loop vacuum belt system for transporting print media to and from the printing zone;
• and
• a vacuum platen system located proximate the printing zone, the vacuum platen system having a platen, having a plurality of vacuum ports therethrough, a vacuum chamber, and a vacuum device for maintaining a negative pressure within the chamber such that an airflow is established through the vacuum ports into the chamber, wherein the vacuum belt system has a belt having perforations, each of said perforations being of a smaller size than each of said ports such that a uniform vacuum holding pressure is exerted on a sheet of print media carried by the belt across the platen and the airflow superjacent the belt in the printing zone is less than an airflow that affects ink drop flight trajectories while a substantially uniform airflow is established for holding an ink-jet print media on said belt, wherein cross-sectional diameter of each of said ports is approximately five times cross-sectional diameter of each of said perforations.