Abstract: A thermal ink jet printhead for a printer has a temperature sensor attached thereto for monitoring the operating temperature thereof. A maximum printhead operating temperature is stored in a memory of the printer's control circuitry and, if the printhead temperature sensed by the temperature sensor during a printing operation exceeds the maximum operating temperature stored is the memory, a signal is generated indicating that the printhead has stopped ejecting ink droplets and must be checked for depriming or a depleted ink supply.

Abstract: An ionographic imaging member containing a conductive layer and a uniform and continuous dielectric imaging layer free of voids, the imaging layer having a dielectric constant of from about 1.5 to about 40 and a thickness of at least about 45 micrometers, the thickness divided by the dielectric constant having a value of from about 30 to about 60 micrometers. This member may be used in an ionographic imaging process.

Abstract: An apparatus which develops an electrostatic image with marking particles. The apparatus includes a developer roller for transporting the marking particles to a position adjacent an electrostatic image for the purpose of developing the image. During deposition of the marking particles on the image, the apparatus senses the charge thereon and in response to the sensed charge, additional marking particles are dispensed into the developer roll housing for use by the developer roller. The apparatus further includes an impoved method for periodically determining the actual concentration of the marking particles within the developer housing in order to modify the rate at which the marking particles are replenished, thereby maintaining an equilibrium concentration of marking particles within the developer housing.

Abstract: A printer member adapted to be used in an ion printing device having a conductive coating positioned on a portion of the marking head near the charge receiver. The conductive coating is electrically connected to the housing in order to substantially equalize the voltage potential of the housing and marking member. The above arrangement enables the device to be set at a single operating state that would allow the device to operate very near its breakdown threshold at all humidity levels.

Abstract: An ionographic imaging member containing a conductive layer and a uniform and continuous dielectric imaging layer free of voids, the imaging layer having a dielectric constant of from about 1.5 to about 40 and a thickness of at least about 45 micrometers, the thickness divided by the dielectric constant having a value of from about 30 to about 60 micrometers. This member may be used in an ionographic imaging process.

Abstract: This invention is a transfer means in a electrographic printing apparatus having a charge retaining member with a relatively high background potential of a first polarity, a transfer corotron having a relatively high potential of a second polarity and providing a transfer region for a transfer of toner to copy sheets, and a pretransfer baffle disposed adjacent to the transfer corotron, the pretransfer baffle being charged to a potential approximately the same as the charged retaining member and having said first polarity, the pretransfer baffle and the charge retaining member forming a gap for the passage of copy sheets to the transfer region, and the copy sheet being in contact with the charge retaining member before reaching the transfer region.

Abstract: The adjustment of the strobe and data voltages to the array gates that drive each of the modulators in an ionographic printing device, in particular the lowering of the data voltage level below the strobe voltage level for each of the array gates. The lower limit on the data voltage level is the voltage level where the generated ions are not shut off completely at the modulating electrode.