Hewlett-packard Company

Brent W Richtsmeier

Todd R Medin

Todd L Russell

Kevin L Glassett

Raymond M Cundiff

Mark S Hickman

William D Meyer

Stephen William Bauer

Shelley I Moore

Damon W Broder

Alpha N Doan

Stephen B Witte

Richard A Becker

Ronald J Selensky

William H Schwiebert

Robert R Giles

W Wistar Rhoads

Jason R Arbeiter

Abdolreza Movaghar

Richard M Kemplin

Aneesa R Scandalis

John Thomas

Brad Nakano

Methods of printing a desired color image on a printing medium by construction from individual ink drops deposited in pixel arrays includes passing a multiple-nozzle ink-discharging pen or an odd number of staggered pen cartridges across the medium multiple times, each pass creating a portion of a respective segment of the image, and periodically advancing the medium so that portions of successively different segments are created by the pen(s). During each pass, the &ldquo;portion-creating&rdquo; function includes discharging from the pen(s) an odd submultiple of the full density of ink desired in the segment of the desired image that is being created, so that printing full density in each segment requires an odd number of passes. The medium is advanced by an odd submultiple of the height of the segment being created in each pass and is preferably advanced after each pass of the pen(s). The portion-creating includes creation by the pen(s) of a multiplicity of spaced-apart diagonal lines. Preferably in each passing step after a first one, the diagonal lines are created in positions such as to at least partially fill in unprinted spaces between previously created diagonal lines. Preferably the diagonal lines are all at a substantially common angle (ideally forty-five degrees) to a pen-scanning direction.

Odd number of passes, odd number of advances, and separated-diagonal-line masking, in liquid-ink printers

A method of printing a desired color image on a printing medium by construction from individual ink drops deposited in pixel arrays includes passing a multiple-nozzle ink-discharging pen across the medium multiple times, each pass creating a portion of a respective segment of the image, and periodically advancing the medium so that the pen creates portions of successively different segments. During each pass, the 'portion-creating' function includes discharging from the pen an odd submultiple of the full density of ink desired in the segment of the desired image that is being created, so that printing full density in each segment requires an odd number of passes, preferably three. The medium is advanced by an odd submultiple of the height of the segment being created in each pass and is preferably advanced after each pass of the pen. For the preferred three passes, the odd submultiple of the height of the segment is preferably one-third. The portion-creating includes creation by the pen of a multiplicity of spaced-apart diagonal lines. Preferably in each passing step after a first one, the diagonal lines are created in positions such as to at least partially fill in unprinted spaces between previously created diagonal lines. Preferably the diagonal lines are all at a substantially common angle (ideally forty-five degrees) to a pen-scanning direction.

Odd number of passes, odd number of advances, and

A color ink-jet printer having a heating blower system for evaporating ink carriers from the print medium after ink-jet printing. A preheat drive roller engages the medium and draws it to a print zone. The drive roller is heated and preheats the medium before it reaches the print zone. At the print zone, a print heater heats the underside of the medium via radiant and convective heat transfer through an opening pattern formed in a print zone heater screen. The amount of heat energy is variable, depending on the type of the print medium. A crossflow fan at the exit side of the print zone direct an airflow at the print zone in order to cause turbulence at the medium surface being printed and further accelerate evaporation of the ink carriers from the medium. An exhaust fan and duct system exhausts air and ink carrier vapor away from the print zone and out of the printer housing.

Heater blower system in a color ink-jet printer

An inkjet printer whereby high density graphics images can be printed without smearing and without either a reduction of print speed or a degradation of print quality is disclosed. Previous methods of inducing drying on inkjet output in printers with heaters did not use print density to adjust heater output. Heater output was simply adjusted based on the type of media so destruction of the media did not take place. The media was given enough time to dry by either lowering the print speed of the printer or utilizing special multi-pass print modes. As a result, the throughput of the printer was reduced. The disclosed inkjet printer allows for greater heater drying to be applied to output printed with greater densities of ink. The inkjet printer comprises a carriage mounted inkjet printing mechanism for applying liquid ink to a print medium as successive columns of dots contained within horizontal swaths to thereby form a portion of the image of an image to be printed on a sheet of print media. The printer and method comprises the steps determining a maximum density of dots in a first horizontal swath, applying a variable quantity of heat to the media based upon the maximum density of said dots and the nature of the print media, and moving a plurality of inkjet nozzles across the print medium and applying a specified amount of liquid ink from specified inkjet nozzles onto the print medium as successive columns of dots contained within a first swath of the image. The maximum print density can be calculated by counting drops of ink in each of several overlapping grids. Thus, the inkjet printer utilizes information about the print density to control the heater output level rather than controlling the print speed of the inkjet printer, or using multi-pass print modes which reduce printer throughput. Similarly, this invention can be applied to print devices that control air flow or fan speed or any other device that provides direct drying of printed media based on the analysis of the ink density of the printing being performed.

Use of densitometer for adaptive control of printer heater output to

An ink-jet printer having a dual drying system. A print heater is disposed at the print zone for heating a portion of the print medium during printing operations to dry ink ejected onto the medium. The printer has means for drying the print medium at a drying location before the medium reaches the print zone to prevent uneven shrinkage of a cellulose-based print medium due to heating the medium at the print zone. The print heater can be controlled to provide a higher temperature at the print zone than the drying means provides at the drying location. The printer provides the capability of independent control of said drying means and said print heater. A method is described for detecting a transparent medium being advanced to a print zone of an ink-jet printer capable of supporting printing operations on a transparent medium as well as an opaque medium, including: providing a sheet of transparent print medium having an opaque strip extending along a leading edge thereof, wherein a reflectivity of the strip is substantially higher than a reflectivity of the transparent print medium; advancing an opaque or transparent print medium along a medium path toward the print zone; and determining whether a print medium being advanced to the print zone is an opaque type or a transparent type by sensing the presence of the opaque strip on said transparent medium.

Ink-jet printer having dual drying system

A color ink jet printer including a print carriage movable along a carriage scan axis, a plurality of non-black color printing ink jet printheads supported by the print carriage and offset relative to each other so that their nozzle arrays are non-overlapping along the media scan axis, and a black printing ink jet printhead having a nozzle array that overlaps along the media axis with one of the nozzle arrays of the non-black color printing ink jet printheads, whereby as the carriage is scanned along the carriage scan axis the nozzle arrays of the non-black color printing ink jet printheads traverse non-overlapping print regions and the nozzle array of the black printing printhead traverses a print region that overlaps one of the non-overlapping print regions traversed by the nozzle arrays of the non-black color printing ink jet printheads.

Ink jet painter having staggered nozzle array for color printing

An inkjet printer applies ink from one or more printheads to media which is supported by a screen platen. The screen platen allows transfer of heat by radiation and convection from a heat generator unit to pre-printing portion of the print zone, an ink-applying portion of the print zone, and a post-printing portion of the print zone.

Method of multiple zone heating of inkjet media using screen platen

To prevent rubbing of the printing mechanism against still wet ink on a buckled or curled sheet of an absorbent print medium after an inkjet printer has printed one swath of a high density image, printing of the next swath is delayed as a function of the maximum density of the ink drops deposited on the print medium for the printed swath(s). The required delay in printing the next swath is dependent on print mode and preferably uses a formula with empirically derived constants to allow sufficient time for the solvent in the ink to evaporate or otherwise disperse and to permit any buckling or curling of the print medium to stabilize. In one preferred embodiment, a maximum density is calculated by counting drops of ink in each of several overlapping grids, and the magnitude and location of the maximum density grid on a prior page is also used to limit the throughput of a next page until a sufficient delay has elapsed to ensure that ink on the prior page will not be smeared when it comes into contact with the next page.

Densitometer for adaptive control of ink drying time for inkjet printer

A color ink-jet printer having a heating and air evacuation system for evaporating ink carriers from the print medium after ink-jet printing. A medium advancement system advances the print medium from an input tray to the print zone. At the print zone, a print heater whose position is fixed in relation to the printer body heats the medium to cause accelerated drying of the ink deposited on the medium. An exhaust fan and duct system exhausts air and ink carrier vapor away from the print zone and out of the printer housing. The duct system includes an elongated inlet opening fixed in position relative to the printer body and disposed along the extent of the printer housing. The air and ink carrier vapors are drawn into the inlet opening and away from the print zone.

Air evacuation system for ink-jet printer

An ink-jet printer having improved print quality and full color printing capability on plain paper media. A radiant print heater heats the medium at the print area to increase the ink carrier evaporation rate. The heater includes a wire heating element placed in a reflectorized cavity beneath the printing area, and radiant heat energy is directed onto the lower surface of the print medium through a grill. The heating element is energized by a low voltage signal. The print heater heats the portion of the medium disposed at the print area during print operations to cause accelerated drying of ink deposited on the medium.

Print area radiant heater for ink-jet printer

Ink-jet printer with print heater having variable heat energy for

A pinch wheel is mounted to be spring-loaded against an exit drive roller in close proximity to a print zone, with the pinch wheel formed by a dual starwheel having two spaced-apart sets of teeth for contacting a newly-printed media surface without puncturing or damaging the media.

Growing community of inventors

San Diego, CA, United States of America

Brent W Richtsmeier