Abstract: An inkjet printer includes a printhead for ejecting ink onto a print medium. The printhead includes electrical and mechanical structure for controlling the ejection of the ink. The printhead includes an ink ejector chip having at least one active device, such as a transistor and the like. A guard ring substantially surrounds select active devices included on the chip. The guard ring tends to prevent latch-up when the chip operates to energize the ink. The chip is manufactured using a substrate devoid of an overlying epitaxial layer which tends to reduce the cost of manufacturing the chip.

Abstract: In a two piece toner cartridge assembly, as typically used in a computer and/or facsimile printing device, comprising separable photoconductor and developer units a unique coupling device is provided whereby the cartridge assembly may be removed from the printing device without the photoconductor unit separating from the developer unit for paper jam clearance or unit replacement. However, if desired the developer unit may be separately removed from the printing device for servicing or replacement without removal of the photoconductor unit.

Abstract: An image scanning apparatus and a torsion oscillator are capable of operating across a dynamic range of possible operating frequencies. The image scanning apparatus uses a light source to produce a light bean, and the oscillator scans the light beam through a scanning pattern. The oscillator includes a plate member having a non-rectangular shape. At least one magnet is disposed on the plate. A surface of the plate member includes a reflective surface for reflecting a light beam. A frame is disposed in a spaced apart relation to a lower surface of the plate member. The fame includes at least one coil configured to induce an electromagnetic force on the at least one magnet to thereby oscillate the reflective surface to a rotational angle of oscillation at an oscillation frequency. The system also includes an imaging surface disposed in the path of the scanning pattern so that the light beam scans across the imaging surface, and a mechanical drive to move the imaging surface.

Abstract: A torsion oscillator (FIG. 1) is stabilized in operation by determining the current resonant frequency (62); in a first procedure, observing the oscillator for change in resonant frequency (64), and then restoring the amplitude and median offset (66) without changing the drive frequency. In an alternative procedure, after determining the resonant frequency (62); setting the drive frequency close to but offset from the current resonant frequency (74), observing the oscillator for change in resonant frequency (76), and the restoring the close offset to the changed resonant frequency (78). By operating slightly off peak, the direction of resonant change is immediately known. The first procedure has less difficulties in implementation, but requires more power.

Abstract: The invention provides an ink jet pen including a cartridge body having a printhead and a replaceable ink cartridge removably positionable on the cartridge body. At least one cooperating elongate recess and at least one projection are located on the mutually facing surfaces of the ink cartridge and the cartridge body. The projection and recess are engageable with one another for guidably positioning the ink cartridge to a desired position relative to the cartridge body.

Abstract: An ink jet heater chip having improved thermal. The chip includes a semiconductor substrate, a first metal resistive, a second metal conductive layer on a first portion of the resistive layer and on a second portion of the resistive layer defining a heater resistor element. A passivation layer having a thickness defined by a deposition process is deposited on the second metal conductive layer and heater resistor element. A cavitation layer is deposited on the passivation layer and etched. A dielectric layer is deposited and etched to provide a dielectric layer overlying the first portion of the resistive layer. An electrical conduit via is etched in the dielectric layer. A third metal conductive layer is deposited in the via for electrical contact with the second metal conductive layer. Separately deposited dielectric and passivation layers enable independent control of the thickness of the dielectric and passivation layers.