Abstract: A dust containment cap for use in a printing device to be supplied with finely pulverized toner which is susceptible of becoming airborne and contaminating surrounding areas employs two brushes arranged in the toner supply opening such that they completely fill the opening but permit the insertion of the neck of a toner bottle to be inserted through them for depositing new toner. Toner that becomes airborne below the brushes is impeded by the brushes from escaping from the opening. The brushes may be installed at downward angles so that together they form a "V"; toner inadvertently spilled on the tops of the brushes gravitates to the bottom of the "V" whence it may be dropped through by agitating the bristles.

Abstract: A data printer has the ability to print machine-readable information and, further instream, the ability to read and analyze such information. Results of that analysis are reporated back to a job control processor which, according to the analysis, monitors print quality, instructs the print engines to adjust print contrast, causes unacceptable pages to be invalidated, rejected and reprinted, and advises the operator regarding corrective actions to improve print quality or to reconcile print jobs.

Abstract: Motor control apparatus is described that is used in a printer that prints on a paper web coming from a roll of paper and has two-sided printing capability using two print mechanisms. The motor control apparatus controls power to several DC motors that either move the paper web from a roll through the printer or provide back tension to the paper web. The control circuits sense paper travel speed and motor loading and thereby sense the effects on paper tension caused by others of the control circuits. The interaction of motor torques provided by the control circuits maintains constant tension on the paper web throughout the printer and thereby assures that there is front to back printing registration on each two-sided printed sheet, and also assures that there is top to bottom centering registration of printing on each sheet of paper when the paper web is cut into individual sheets of paper.

Abstract: A printer apparatus having two-sided printing capability is taught. Two printing mechanisms are provided that can simultaneously print both sides of roll paper. The printing mechanisms are physically oriented with respect to each other and to a simple paper handling/routing mechanism comprised of rollers so that when only one printing mechanism is installed to provide only one-sided printing, the paper handling mechanism need not be modified but the roll paper is merley routed differently around the rollers. Retroactively, a second printing mechanism may simply be installed in the printer for two-sided printing and the roll paper is routed around the rollers differently to route the roll paper to and from the second printing mechanism.