Abstract: Errors in regard to toner materials which may or may not correspond to toner materials installed in a developer unit of a print engine are avoided by providing storage of data concerning the toner in the printer rather than the dedicated processor. A feedback link is thus developed which extends from the developer unit or print engine through the dedicated processor to the supporting processors. Confidence levels in the correspondence of the information and the installed toner are increased by use of a simple switch position associated with the location of a developer unit. The feedback arrangement for avoidance of printing errors is also fully compatible with a customer changeable developer feature while allowing the printer to be operated in accordance with operating parameters specific to a special purpose toner such as MICR or a color toner.

Abstract: In a computer controlled printing system including a dedicated processor for routing print jobs from supporting processors to printers or print engines thereof, errors in regard to toner materials which may or nay not correspond to toner materials installed in a developer unit of a print engine are avoided by providing storage of data concerning the toner in the printer rather than the dedicated processor. A feedback link is thus developed which extends from the developer unit or print engine through the dedicated processor to the supporting processors. Confidence levels in the correspondence of the information and the installed toner are increased by use of a simple switch positional associated with the location of a developer unit. The feedback arrangement for avoidance or printing errors is also fully compatible with a customer changeable developer feature while allowing the printer to be operated in accordance with operating parameters specific to a special purpose toner such as MICR or a color toner.

Abstract: Sheet feeder having adaptive mechanism for assuring dependable automatic operation when the stack of sheets to be fed consists of sheets having varying thicknesses and weights. In a sheet feeder having pickers to move a document from the top of a stack of sheets supported by a moveable table to a feed-in position, the latter possibly including a vacuum belt for moving the document, sensors supply signals to indicate a sheet has been picked. After moving the pickers and table to initial positions, the controller moves the picker to a predetermined reference position. If a sheet is picked above or below the predetermined initial position, the position of the table is adjusted accordingly.

Abstract: A method for producing duplex copies from a duplex original wherein only one copy of the odd or even sides of the original documents is made during the first circulation of the originals to and from the exposure platen. During each subsequent circulation of the original documents, excluding the last circulation, two copies of the odd or even sides of the original are produced and either stored in a buffer tray if one side of the copy sheet is blank or transported to an exit tray if duplex copying has been completed on the copy sheet. Only one copy of the odd or even sides of the original documents are made during the last circulation and transfered to the blank sides of the copy sheets in the buffer tray to complete a duplex copy.

Abstract: Photoconductor panels are automatically replaced in an electrophotographic copier or printer after it is determined that the panels require replacement and the machine has entered into a run-out mode. The run-out mode is defined as the time period at the end of a copy processing operation between the transfer of the last image to a copy sheet and the final processing of that copy sheet by the machine. The photoconductor panel is completely replaced without interrupting machine operation and in a manner transparent to the user. A control circuit or process interprets the machine states to determine presence of the run-out mode.