International Business Machines Corporation

Francis J Perry

Anthony Vesci

Richard Curtis Alt

Robert K Evans

Warren L Chocholaty

Richard H Darling

Electronic lead determining circuitry operates to advantage with nonlinear relative movement between a paper record medium and an ink drop projector carrier of ink drop printing apparatus. Electronic lead determining circuitry is arranged for calculating the proper lead times for displacing the normal print enabling signals by factors dependent on the actual carrier positions and the lead for projecting ink drops at the desired positions. Ink drop printing apparatus of the type having a carrier bearing an ink drop projector across a record medium at a velocity relative to the record medium which may be varying substantially--either by design or unintentionally--, and bearing print position location detecting elements, and bearing ink drop projection controlling elements is perfected by controlling electronic circuitry for calculating lead time at a given print position for enabling printing at a predetermined designated print position precisely at the predetermined desired location on the paper. Preferably, a velocity-time profile for the apparatus is chosen for low g-force loading of the moving components, and printing is effective over most of the profile in contradistinction to conventional printing over linear portions only of conventional profiles. Phase locked oscillator loop circuitry is used for tracking the carrier position and adjusting phase, while several alternate lead calculating circuits are arranged in cooperation therewith. Print position and carrier travel direction data are updated in real time as the apparatus operates under data processing control.

Circuitry for perfecting ink drop printing at varying carrier velocity

Apparatus and method for detecting and correcting for evaporation from recirculated unused ink drops in an ink jet printer. The specific gravity of the recirculating ink is compared with that of a standard by measuring the time of fall of heavy floats through reservoirs of circulated and uncirculated fluid. A significant difference in fall times is compensated by the replenishment of fluid in the recirculating ink supply.

Ink maintenance sensor

A high pressure fluid source is connected to a primary orifice and a valved orifice of a binarily activated pressure regulator. The primary orifice alone supplies the fluid at a pressure below the minimum desired, and both orifices together supply the fluid at a pressure greater than the maximum desired. A sensor at the output is adjusted to open the binary valve when the minimum pressure is reached, and close the valve when the maximum pressure is reached, thus cycling between the two conditions.

Digital flow pressure regulator

An ink jet printer employs a wire mesh gutter electrode assembly and a wire mesh high voltage electrode, each having angled or skewed configurations geometrically related for providing a relatively narrow constricted path for ink droplets, so that charged and partially charged droplets, which are not used for imprinting, traverse a short path and are effectively captured and collected for recirculation and use in the ink recording process.

Ink collector in ink jet printer

Ink supply system and sequencing for purge, startup, operation, and shutoff of pressurized ink jet systems. Employing an ink jet head having an inlet, startup is accomplished by filling the head with ink, closing an inlet valve, building pressure behind the valve to a level significantly greater than required for operation, and opening the valve. The system includes an inlet valve connecting a pump from a reservoir to the ink jet head, and an outlet valve connecting an outlet from the head to the reservoir and a vacuum source. At shutoff, the inlet valve is closed with the outlet valve open to create a negative pressure in the head.

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Morgan Hill, CA, United States of America

Francis J Perry