Xerox Corporation

Stephen P Wilczek

John W Daughton

Anthony M Federico

Ernest L Legg

Edward L Steiner

Frank M Nelson

Kenneth Gillett

Kenneth W Laskowski

Gerald A Gray, Jr

Richard T Ziehm

Phillip J Batchelor

Raymond R Husted

James M Donohue

Keith G Bunker

George E Mager

Robert E Markle

Robert L Traister

George E Baker

Glen A Dumas

Henry E Mannella

George H Place, Jr

James J Petery

Hari K Prasad

Curtis B Downing

Michael E Edmunds

The present invention is a multiprocessor machine control having at least one processor for performing input and output operations and communicating with a master processor over a communication channel. Common synchronizing signals are conveyed to both the input/output processor and the master processor independent of the communication channel. This provides the input/output processor with immediate access to timing and synchronizing information for prompt response to general control information from the master processor. The master processor downloads instructions or provides general instructions to the input/output processor. These downloaded instructions are given priority and timely executed without further communication with the master processor. At completion of the operation the master processor is informed that the particular operation has been performed.

Multiprocessor control synchronization and instruction downloading

The present invention is a multiprocessor machine control system in which the failure of one of the processors to reset can be ignored by the rest of the control system. In particular, a software crash or other abnormality on one of the processors will generate a reset procedure. If the processor cannot be reset, this will indicate a processor board failure such as a hardware failure. If the processor and its controlled elements are not crucial to the machine operation, then the control wll ignore the failed processor as though it were not in the control system, and continue with machine operation.

Remote processor crash recovery

The present invention includes a plurality of input/output processors communicating with a master processor. Each of the input/output processors has a filtering mechanism to filter the inputs before transmission to the master over the communication channel precluding the necessity of filtering at the master. More importantly, the shared communications system is not loaded down with every change of an input. Because of this feature, only meaningful changes are put on the communication line, thus substantially reducing its load which makes its effective response time stay high. The inputs when received at the master can be immediately handled to improve the central processor response time. Two types of filtering are provided, in particular, transition and debounce filtering to respond to switch and sensor inputs. Also, there is provided a means to programmably select the type of filter and the time period of filtering.

Filtered inputs

A copy reproduction machine is subdivided into discrete operating modules and coupled together by a shared communication line over which operating messages from and to the modules are transmitted. Each module includes a receiver for intercepting and capturing messages bearing the module's address and a transmitter for transmitting messages from the module and addressed to other modules over the shared communication line.

Message transmitting system for reproduction machines and copiers

The present invention is a multiprocessor control system that allows full job recovery after a machine power down or after a malfunction or software crash or temporary power outage. In particular, essential variables such as the state and status of the machine and the programmed job at the time of the malfunction are maintained in nonvolatile memory. This information is continually updated in nonvolatile memory. Once the control system has reset and reinitialized all the control elements after a malfunction, the control restores or downloads all the relevant variables in the nonvolatile memory to the various control elements to maintain status. In another embodiment, the essential variables are maintained in RAM locations in a master processor and saved for downloading to the control elements.

Control system job recovery after a malfunction

A data communication system having a master unit, an interface, and one or more remote units. The master unit includes a programmable controller having a data processor, memory storage for storing programs and command and data bytes, and address and data buses. The interface is connected to the master unit via the address and data buses, and includes a memory connected to the data bus for temporarily storing command and output data bytes from the master unit pending transmittal thereof to the remote units and for storing input data bytes from the remote units pending transfer thereof to the master unit. A first communication path, along which command and data bytes from the interface memory are transmitted to the remote units, couples the interface with the remote units. A second communication path, along which input data bytes from the remote units to the interface memory are transmitted, couples the remote units with the interface.

Serial data communication system having simplex/duplex interface

An electrostatographic type copying or reproduction machine incorporating a programmable controller to operate the various machine components in an integrated manner to produce copies is disclosed. The controller carries a master program bearing machine operating parameters from which an operating program for the specific copy run desired is formed and used to operate the machine components to produce the copies programmed. A multiple prioritized interrupt system is employed to distribute the operating program to the machine. Self check routines check the operational integrity of the controller prior to start-up of the machine and periodically while the machine is processing copies.

Copy reproduction machine with controller self check system

A reproduction machine for making either single sided or duplex copies, and incorporating automatic document handler and sorter for handling original documents being copied and copies made. To enable copy quality to be checked, either when the machine is stopped or in the midst of a copy run, a sample copy is provided for. Where the sample copy is selected during a copy run, an accommodation in copy billing rate is made.

Sample copy system for xerographic reproduction machine

A data communication system for an electrophotographic type reproduction machine or copier having a master unit, an interface, and one or more remote units. The master unit includes a programmable controller having a data processor, memory storage for storing programs and command and data bytes, and address and data buses. The interface is connected to the master unit via the address and data buses, and includes a memory connected to the data bus for temporarily storing command and output data bytes from the master unit pending transmittal thereof to the remote units and for storing input data bytes from the remote units pending transfer thereof to the master unit. A first communication path, along which command and data bytes from the interface memory are transmitted to the remote units, couples the interface with the remote units. A second communication path, along which input data bytes from the remote units to the interface memory are transmitted, couples the remote units with the interface.

Serial data communication system for a reproduction machine

An electrostatographic type copying or reproduction machine for making duplex as well as simplex copies. To enable offset margins on the original documents being copied to be matched on both sides of a duplex copy, a control is provided which when actuated moves the second side image into alignment with the first side image.

Reproduction machine with duplex image shift

A reproduction machine for making two-sided or duplex copies. When there is an odd number of simplex original documents to be copied in the duplex mode, the last copy sheet bears an image only on one side. The present invention provides a control system for operating various machine components in response to such an occurrence in order to optimize the throughput capability of the machine.

Growing community of inventors

Fairport, NY, United States of America

Stephen P Wilczek