1
James A Parnell, John C Venthem, Charles D Zinsmeyer: Ribbon cassette storage and transfer apparatus for a printer. Summagraphics Corporation, Rosen Dainow & Jacobs, December 7, 1993: US05267802 (18 worldwide citation)

Apparatus is disclosed for use with printers (or plotters) for storing and transferring ink-containing ribbon cassettes between a print head and a storage location. The printers (or plotters) are of the type which include a print head that is not as wide as the width of the medium to be printed on s ...


2
John C Venthem: Belt-drive tensioning system which uses a pivoting member. Summagraphics Corporation, Rosen Dainow & Jacobs, May 25, 1993: US05214448 (9 worldwide citation)

A belt drive tensioning system for a motor drive positioning system, especially for X-Y digital plotters. The tensioning system employs spring-loading involving pivoting motion of a motor-mounted plate relative to a fixed plate to accurately preset and maintain constant the desired belt tension. A p ...


3
John C Venthem, James A Parnell, Mark Hill, Dan R Poole: Pen tip position detector. Ametek, Amster Rothstein & Ebenstein, December 19, 1989: US04888710 (6 worldwide citation)

Apparatus, for use in conjunction with a digital plotter incorporating controlled multiple markers to create displays, for determining the position of the markers along axes of movement, comprises a detector assembly disposed at a fixed axial position relative to the plotter, and a driver for moving ...


4
John C Venthem, Marlan L Schmidt, James A Parnell: Sheet medium transport system, particularly for printers and plotters. Summagraphics Corporation, Rosen Dainow & Jacobs, April 11, 1995: US05405205 (4 worldwide citation)

The invention disclosed herein provides a method and apparatus for counteracting the effects of a localized drag on a sheet medium as it is being moved by a drive system, for example, in a printer or plotter to prevent misregistration of the sheet medium with the X-axis drive system as the sheet med ...


5
John C Venthem, James A Parnell: Apparatus for raising and lowering plotter marking devices. Summagraphics Corporation, Rosen Dainow & Jacobs, July 26, 1994: US05333005 (1 worldwide citation)

Apparatus especially X-Y plotters having a marking device for marking a surface. A support is provided for supporting the marking device. The support is movable along an axis of the housing while the marking device can be selectively raised and lowered relative to the surface. The raising and loweri ...