Compaq Computer Corporation, Inc.

James L Stortz

David B Wallace

Donald J Hayes

Ralph K Williamson

Power consumption of an audio system of a computer is controlled, in response to an audio power management event, by altering the operation of the audio system in a manner that changes the power consumption of the audio system.

Audio power management

A method for providing a video buffer includes reserving an incremental video buffer in system memory, and controlling the use of a dedicated video buffer and the incremental video buffer to provide a composite video buffer.

Composite video buffer including incremental video buffer

A single side interconnectable ink jet printhead. In one embodiment thereof, the ink jet printhead includes a lower body portion having a plurality of conductive sections mounted to a top side of the lower body portion and a corresponding plurality of conductive pins projecting from a bottom side of the lower body portion. Each of the conductive sections is electrically connected to the corresponding one of the conductive pins. A bottom side surface of each one of a plurality of generally parallel, longitudinally extending first intermediate body portions, each formed of an active piezoelectric material poled in a first direction parallel to the top side surface of the lower body portion is conductively mounted to a portion of the top side surface of the lower body portion. A bottom side surface of each one of a plurality of generally parallel, longitudinally extending second intermediate body portions, each formed of an active piezoelectric material poled in a second direction opposite to the first direction is conductively mounted to a top side surface of a corresponding one of the first intermediate body portions and a bottom side surface of an insulative upper body portion is conductively mounted to a top side surface of each of the plurality of second intermediate body portions.

Single side drive system interconnectable ink jet printhead

A spot size modulatable, drop-on-demand type ink jet printhead for producing grey-scale images on a substrate. The ink jet printhead includes a main body portion having an ink-carrying channel extending therethrough and a piezoelectric actuator coupled to the ink-carrying channel. A spot size for droplets to form when striking the substrate after ejection from the ink-carrying channel is selected and a look-up table translates the selected spot size into a time period during which a voltage pulse is to be applied to the piezoelectric actuator by an associated switching structure to cause the ejection of a droplet of ink capable of forming a spot having the desired size. An associated control circuit causes the switching structure to initiate application of the voltage waveform, determines whether the voltage waveform has been applied to the piezoelectric actuator for the time period and terminates application of the voltage waveform upon expiration of the time period. The control circuit includes a sequencer which selectively asserts or deasserts at least one control signal to the switching structure, a timer which instructs the sequencer to initiate application of the voltage waveform and determines time elapsed since initiating application, and a comparator which compares the time period produced by the look-up table and the elapsed time determined by the timer.

Spot size modulatable ink jet printhead

A digital driver for an ink jet printhead and an associated method for selectively applying voltage to a piezoelectric sidewall actuator of the ink jet printhead. The digital driver includes positive and negative voltage sources, a first switching element having a first control input, a first voltage supply input connected to the positive voltage source, and a first output, and a second switching element having a second control input, a second voltage supply input connected to the negative voltage source, and a second output connected to the first output to provide a single output connected to the piezoelectric sidewall actuator. By asserting the first control input for a first time period, the first switching element generates a positive voltage pulse at the single output to displace the sidewall actuator from a rest position to a first position. Next, by simultaneously deasserting the first control input and asserting the second control input, the second switching element generates a negative voltage pulse at the single output to displace the sidewall actuator from the first position, past the rest position, to a second position. Next, by deasserting the second control input, the sidewall actuator passively returns to the rest position. The return to the rest position may be assisted by discharging the printhead after deassertion of the second control input, by re-applying the first voltage for a second, shorter, time period to actively drive the sidewall actuator towards the rest position, or by both.

Dual element switched digital drive system for an ink jet printhead

An ink jet printhead and an associated method for operatively driving the ink jet printhead to cause the ejection of a volume modulatable droplet from an ink-carrying channel thereof partially defined by a piezoelectric sidewall actuator. The voltage applied across the sidewall actuator is raised from a rest voltage to a first voltage to deflect the sidewall actuator from a rest position to a first position and maintained at the first voltage for a first period of time. The voltage applied across the sidewall actuator is then dropped to a second voltage, lower than the rest voltage, to deflect the sidewall actuator from the first position, past the rest position, to a second position and maintained at the second voltage for a second period of time. The voltage applied across the sidewall actuator is then returned to the rest voltage to deflect the sidewall actuator back to the rest position. The first and second time periods are selected, relative to each other, to select a droplet volume for ink ejected from the ink-carrying channel. The voltage applied across the sidewall actuator is then returned to the rest voltage, thereby causing the ejection of a droplet of ink having the selected droplet volume.

Droplet volume modulation techniques for ink jet printheads

A differential drive system is used to actuate an ink jet printhead having a spaced, parallel series of internal ink receiving channels opening outwardly through ink discharge orifices formed in the printhead body. The channels are laterally bounded by a spaced series of piezoelectrically deflectable internal sidewall actuator sections of the printhead body interdigitated with the channels. The printhead body is specially configured to facilitate wiring access to spaced apart first and second electrical connection portions on each of the actuators. Electrical leads from a first controller are connected to the first actuator portions and are ganged in groups that are selectively connected to a driving voltage source, or to ground, by the first controller. A second controller has a first set of electrical leads similarly ganged in groups and connected to a first set of the second actuator portions, and a second set of unganged electrical leads individually connected to the rest of the second actuator portions. The second controller is operative to selectively connect any of its individual leads, or any of its ganged lead groups, to the driving voltage source or to ground. In conjunction with the dual controllers, this combination of ganged and individually addressable leads connected to the first and second actuator portions permits the actuators to be differentially driven in a manner digitally synthesizing a more complex bipolar drive system.

Differential drive system for an ink jet printhead

A single side interconnectable ink jet printhead and an associated method for manufacturing the same. The ink jet printhead includes a lower body portion having a plurality of conductive sections mounted to a top side of the lower body portion and a corresponding plurality of conductive pins projecting from a bottom side of the lower body portion. Each of the conductive sections is electrically connected to the corresponding one of the conductive pins. A bottom side surface of each one of a plurality of generally parallel, longitudinally extending first intermediate body portions, each formed of an active piezoelectric material poled in a first direction parallel to the top side surface of the lower body portion is conductively mounted to a portion of the top side surface of the lower body portion. A bottom side surface of each one of a plurality of generally parallel, longitudinally extending second intermediate body portions, each formed of an active piezoelectric material poled in a second direction opposite to the first direction is conductively mounted to a top side surface of a corresponding one of the first intermediate body portions and a bottom side surface of an insulative upper body portion is conductively mounted to a top side surface of each of the plurality of second intermediate body portions.

Method of manufacturing a single side drive system interconnectable ink

A switched digital drive system is used to actuate an ink jet printhead having a spaced, parallel series of internal ink receiving channels opening outwardly at front ends thereof through ink discharge orifices formed in the printhead body. The channels are laterally bounded by a spaced series of piezoelectrically deflectable internal sidewall sections of the printhead body interdigitated with the channels. The drive system includes a series of electrical actuation leads each connected to a different one of the sidewall sections, and dual transistor switch structures connected in the leads with each switch, in turn, connected to positive and negative DC voltage sources. To actuate a selected channel, the switches associated with its opposite bounding sidewall sections are operated in a manner sequentially (1) deflecting the sidewall sections outwardly away from initially undeflected positions thereof by imposing constant, opposite polarity voltages thereon, (2) reversing the polarities of the constant voltages to deflect the sidewall sections into the channel, and then (3) imposing a series of voltage pulses of sequentially opposite polarities on each of the inwardly deflected sidewall sections to controllably return them to their initial undeflected positions.

Switched digital drive system for an ink jet printhead

A drop on demand type ink jet printhead. The ink jet printhead includes a cover plate formed from an active material, a main body portion having an ink-carrying channel axially extending therein and a device for supplying a pressurized flow of ink to the ink-carrying channel. A rear side surface of the cover plate is mounted to a front side surface of the main body portion to block the ejection of pressurized ink therefrom. When an electric field is applied across the cover plate, the displacement of the cover plate caused thereby provides a path for the ejection of ink from the ink-carrying channel. Specifically, the cover plate includes an edge surface which extends from a front side surface thereof to the rear side surface such that, when the electric field is applied thereacross, an orifice defined by the edge surface and in communication with the ink-carrying channel is formed for the ejection of pressurized ink therefrom. The edge surface may be formed by respective side surfaces of first and second plate sections which lay flush with each other or first and second apertures formed in first and second plate sections which are mounted front to rear.

Ink jet printhead having a modulatable cover plate

A digital driver for an ink jet printhead and an associated method for selectively applying voltage to a piezoelectric sidewall actuator of the printhead. The digital driver includes positive, negative and neutral voltage sources, a first switching element having a first control input, a first voltage supply input connected to the positive voltage source and a first output, a second switching element having a second control input, a second voltage supply input connected to the negative voltage source and a second output, and a third switching element having a third control input, a third voltage supply input connected to the neutral voltage source and a third output. The first, second and third outputs are connected together to provide a common output for connection to the piezoelectric sidewall actuator. By asserting the first control input for a first time period, the first switching element generates a positive voltage pulse at the common output to displace the sidewall actuator from a rest position to a first position. Next, by simultaneously deasserting the first control input and asserting the second control input, the second switching element generates a negative voltage pulse at the common output to displace the sidewall actuator from the first position, past the rest position, to a second position. Finally, by deasserting the second control input and asserting the third control input, a path to ground potential is provided at the common output, thereby driving the return of the sidewall actuator to the rest position.

Three element switched digital drive system for an ink jet printhead

The body of a piezoelectrically operable ink jet printhead is mounted in an upper side surface groove formed in a mounting plate member. A rear bottom section of the printhead body has an exposed top side surface portion which is flush with the top side of the mounting plate member and terminates forwardly of its rear end. A high density parallel array of mutually spaced linear conductive traces is formed on this exposed top side surface portion of the printhead body, these traces being used to transmit electrical operating signals from a separate electronic driver to piezoelectrically drivable channel sidewall sections within the interior of the printhead body. A multi-tiered printed circuit board secured to the top side of the mounting plate member is used to connect the printhead to the electronic driver. The circuit board has a series of linear traces formed on its bottom side which register with and are soldered to the closely spaced printhead body traces, a spaced series of lower density spacing contact pads formed on its top side and releasably engageable with correspondingly spaced contact pads on the electronic driver, and internal crossover circuitry that operatively connects the high density underside linear traces of the circuit board to its lower density top side contact pads.

Growing community of inventors

Spring, TX, United States of America

James L Stortz