Hewlett-packard Company

Anthony W Ebersole

Robert Warren Beauchamp

Chuong C Ta

John A Underwood

Todd R Medin

Todd L Russell

A dust shield for preventing paper dust from fouling a printer and printhead mechanism is disclosed. In a sprocket-wheel paper drive printer, the sprockets are at least partially encased as they enter and exit the holes in the paper. Paper particles are trapped and then channelled away from mechanisms, such as a thermal ink jet cartridge printhead, whose operation may be detrimentally affected by such dust.

Dust shield for a printer

An automatic sheet feed alignment system is described for feeding sheets of print media such as paper to print mechanism in alignment with the print mechanism. A single motor drives a main sheet advance roller, and is also coupled to a sheet pick roller through a non-reversing clutch. An idler roller is disposed adjacent the drive roller. To feed a sheet into the print position, the motor drives the main drive roller and sheet pick roller in a sheet advancing direction, until the sheet leading edge is advanced into and past the nip between the main drive and idler rollers. The motor direction is then reversed so that the main roller retracts the sheet. Because the sheet pick roller is not driven in the reverse direction, a buckle is formed in the sheet between the sheet pick roller and the nip, tending to align the leading sheet edge with the nip. The motor direction is then reversed to drive the sheet forward to the print position, its leading edge having been aligned.

Sheet alignment using reverse advance roll and stationary pick roll

A belt tensioner for a belt and pulley system is disclosed. The tensioner has a camming surface upon which a pulley axle rides, maintaining substantially uniform tension in the belt despite competing forces of the belt tension and a tensioner holding spring. The camming surface profile is generated, for example, when using a spring holding mechanism, by differentiating Hooke's Law.

Belt tensioner

A printhead cartridge and carriage assembly (10) for use with ink-jet printers is disclosed. The assembly is provided with means (56) for ensuring that an ink-jet cartridge (20) is securely locked in place in a cartridge carrier (12), means (78, 78a, 80, 80a, 82, 82a) for ensuring that cartridge is registered in a given, fixed, repeatable position each time, means (128) for ensuring that the cartridge is spaced from the printing medium (40) a minimum, fixed distance, means (100) on the carriage for maintaining this fixed distance, and interconnect means (84) for connecting a printhead assembly (34) on the cartridge with a microprocessor for controlling the pattern of ink drop ejection. The assembly further includes a preloader assembly (106) for preventing backward rotational pivoting of the carriage about a slider rod (44) associated with a platen (46) of the printer and for urging the carriage toward the medium on the platen. Finally, a dust barrier (132) protects the interconnect means at the contact to the printhead assembly.

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Poway, CA, United States of America

Anthony W Ebersole