PAUL ROBERT ERICKSON
Pilots at Woodview Ct, Prior Lake, MN

5790150, Aug 4, 1998

Feb 17, 1994

8/197966

Steven L. Lidke - Brooklyn Park MN
Paul R. Erickson - Prior Lake MN
Jeff D. Pagel - Inver Grove Heights MN

Colorspan Corporation - Eden Prairie MN

B41J 215, B41J 2300, B41J 221

347 41

A printer controller for an ink jet printer controls a print head to selectively print only a portion of the print dots at pixels locations in a print swath during each pass of a print carriage across a print medium. At least four passes are made before the print medium is advanced to a new print swath. The portion of the pixel locations for each pass are chosen such that no pixel location to be printed on that pass is orthogonally or diagonally adjacent to any other pixel location to be printed in the same pass. To improve linear print speed, the print carriage is moved across the print medium at a speed that is greater than a maximum firing rate for the print head divided by a print dot density for the ink jet printer.

5969729, Oct 19, 1999

Apr 20, 1995

8/425107

Paul R. Erickson - Prior Lake MN
David H. Bennefeld - Ramsey MN
John P. Novotny - Burnsville MN

Colorspan Corporation - Eden Prairie MN

B41J 2938, B41J 29393

347 9

An ink on demand type ink jet head energization system is provided to drive ink out of a nozzle in the head. The head contains at least one nozzle for discharging ink. The power applied to the nozzle is modified to include a noise component. By providing a driving voltage which varies between firings, the head produces ink droplets which differ in size between firings. Preferably, the voltage is randomly or pseudo-randomly varied over a range of from 50 to 100% of maximum voltage, and a new voltage is provided for each successive firing of the head. This variation of drive voltage produces ink dots which randomly vary in size at a rate too dense to be perceived by a viewer, and successfully reduces perceived artifacts in the printed output.

5805183, Sep 8, 1998

Nov 10, 1994

8/337074

Steven L. Lidke - Chaska MN
Jeff D. Pagel - Inver Grove Heights MN
Paul R. Erickson - Prior Lake MN

LaserMaster Corporation - Eden Prairie MN

B41J 2145, B41J 2938

347 41

A scanning head ink jet printer utilizes variable paper advance interlacing. The printer includes a plurality of heads each having a plurality of rows of uniformly spaced ink jets which print different colors. A printing medium is advanced in a series of non-uniform distances (d. sub. 1, d. sub. 2, d. sub. 3, d. sub. 4) the sum of which is equal to the total number of uniformly-spaced ink jets (n) of one of the colors times the uniform spacing (s) of one pixel row from an adjacent pixel row. In a specific embodiment, a total advance of the printing medium is equal to the total number of uniformly-serial spaced ink jets of one color is 48, the spacing is four pixels, and the non-uniform distances include 49, 49, 45 and 49 pixels.

5367328, Nov 22, 1994

Apr 22, 1994

8/231275

Paul R. Erickson - Prior Lake MN

LaserMaster Corporation - Eden Prairie MN

B41J 2175

347 7

An ink refill system is provided for an ink jet printer having a print carriage that traverses across a print medium and is adapted to receive one or more ink jet cartridges. The ink refill system includes a disposable ink jet cartridge removably mountable in the print carriage and constructed as a self-contained unit that includes a print head and an ink supply container that stores a first quantity of liquid ink at a given subatmospheric pressure hydrodynamic condition. An ink reservoir external to the print carriage stores a second quantity of ink for replenishing the first quantity of ink in the ink supply container. Flexible supply tubing couples the ink reservoir to the ink supply container to supply ink from the second quantity of ink to the first quantity of ink during operation of the ink jet printer as the print carriage traverses across the print medium. A mechanism for refilling the ink supply container of the ink jet cartridge from the external ink reservoir during operation of the ink jet printer as the print carriage traverses across the print medium operates such that the refilling of the ink supply container is accomplished in a manner that preserves the negative pressure hydrodynamic condition of the ink jet cartridge.

5877793, Mar 2, 1999

Nov 18, 1997

8/972829

Paul R. Erickson - Prior Lake MN

ColorSpan Corporation - Eden Prairie MN

B41J 201

347 85

An ink refill system is provided for an ink jet printer having a print carriage that traverses across a print medium and is adapted to receive one or more ink jet cartridges. The ink refill system includes a disposable ink jet cartridge removably mountable in the print carriage and constructed as a selfcontained unit that includes a print head and an ink supply container that stores a first quantity of liquid ink at a given sub-atmospheric pressure hydrodynamic condition. An ink reservoir external to the print carriage stores a second quantity of ink for replenishing the first quantity of ink in the ink supply container. Flexible supply tubing couples the ink reservoir to the ink supply container to supply ink from the second quantity of ink to the first quantity of ink during operation of the ink jet printer as the print carriage traverses across the print medium. A mechanism for refilling the ink supply container of the ink jet cartridge from the external ink reservoir during operation of the ink jet printer as the print carriage traverses across the print medium operates such that the refilling of the ink supply container is accomplished in a manner that preserves the sub-atmospheric pressure hydrodynamic condition of the ink jet cartridge.

5369429, Nov 29, 1994

Oct 20, 1993

8/139576

Paul E. Erickson - Prior Lake MN

LaserMaster Corporation - Eden Prairie MN

B41J 2175

347 7

A continuous ink refill system for an ink jet printer that uses disposable ink jet cartridges having a first predetermined ink capacity includes an ink reservoir that is external to a print carriage on which the disposable ink jet cartridges are mounted. The ink reservoir contains a second predetermined ink capacity that continuously refills an ink container within the disposable ink jet cartridge by a passive pressure differential between the disposable ink jet cartridge and the ink reservoir. The disposable ink jet cartridge is removably mountable in the print carriage and is a self-contained unit having a print head and an ink supply container maintained at a sub-atmospheric pressure that supplies the first quantity of ink to the print head. The ink reservoir storing the second quantity of ink that replenishes the ink supply container is limited to some multiple of the first quantity of ink above which said print head does not reliably operate. Tubing connects the ink supply container to the ink reservoir for transporting ink between the two by means of capillary action.

5629727, May 13, 1997

Feb 21, 1996

8/604401

Paul E. Erickson - Prior Lake MN

B41J 2175

347 85

A continuous ink refill system for an ink jet printer that uses disposable ink jet cartridges having a first predetermined ink capacity includes an ink reservoir that is external to a print carriage on which the disposable ink jet cartridges are mounted. The ink reservoir contains a second predetermined ink capacity that continuously refills an ink container within the disposable ink jet cartridge by a passive pressure differential between the disposable ink jet cartridge and the ink reservoir. The disposable ink jet cartridge is removably mountable in the print carriage and is a self-contained unit having a print head and an ink supply container maintained at a negative pressure that supplies the first quantity of ink to the print head. The ink reservoir storing the second quantity of ink that replenishes the ink supply container is limited to some multiple of the first quantity of ink above which said print head does not reliably operate. Tubing connects the ink supply container to the ink reservoir for transporting ink between the two by means of capillary action.

5469201, Nov 21, 1995

Aug 30, 1994

8/298122

Paul R. Erickson - Prior Lake MN
Tim C. Schooler - Eden Prairie MN

LaserMaster Corporation - Eden Prairie MN

B41J 2175

347 85

An ink supply line support system (100) for a continuous ink refill system (10) for an ink jet printer (90) having a print carriage (91) that traverses across a print bed (96) and is adapted to receive one or more disposable ink jet cartridges (12). The ink supply line support system (100) includes an elongate guide structure (102) having a first end (104) operably connected to the ink jet printer (90) at a fixed location (106) and a second end (108) operably connected to the print carriage (91). The second end (108) is movable relative to the first end (104) in a first orientation along the direction in which the print carriage (91) traverses across the ink jet printer (90), but is substantially rigid relative to the first end in a second orientation that is transverse to the first orientation. An attachment mechanism (110) is positioned along an exposed surface (111) of the guide structure (100) for detachably securing at least a portion of at least one ink supply line (16) to the guide structure (102). The ink supply line support system (100) is particularly adapted for large format ink jet printers (90) that are capable of producing high quality, full ink coverage prints on print beds (96) greater than 61 cm (24 inches) wide.

5243391, Sep 7, 1993

May 1, 1992

7/876974

Tony Williams - St. Paul MN
Paul Erickson - Prior Lake MN
Stan Dorr - St. Paul MN

Printware, Inc. - St. Paul MN

G03G 1506, G03G 1510

355256

The separation between two plates or electrodes--between which plates a developer solution is applied to develop a latent electrostatic charge image on a photoconductive medium within an electrophotographic imager--is varied in proportion to a detected concentration of toner within the developer solution. Resultantly to this control of the separation of the two plates, the proximity of the medium's photoconductive surface to a one plate, and the strength of the electric field between that plate and the photoconductive surface, is also controlled. By the control the thickness and density of the applied toner film is maintained constant, and a high quality image is maintained, despite depletion of toner from the developer solution. The toner concentration is preferably sensed as electrical resistance. A control circuit responsive to this sensed resistance preferably includes an analog-digital converter, a microprocessor, a stepper motor driver/controller, and a stepper motor rotating a cam.