Adapter for raster output scanning printer
First Claim
1. An adapter for interfacing a digital electronic image processor with a raster output scanning printer, said adapter having dedicated input and output connections for printer control and operation, said adapter comprising:
- means for receiving at a first dedicated input connection digital command data from said electronic image processor and for initiating control functions in response thereto;
means for receiving at a second dedicated input connection digital clock signals of a predetermined uniform frequency transmitted thereto by said electronic image processor and for distributing said clock signals throughout said adapter;
means for receiving in bit parallel format at a set of third dedicated input connections packets of video print information from said electronic image processor and for retiming said video information for transmission to said printer;
means for monitoring the transmission of video print information to said printer and for generating data request signals at a first dedicated output connection to said electronic image processor in order to thereby request additional packets of video print information from said electronic image processor;
means for monitoring the status of said adapter and said printer and for serializing status information and generating said status information at a second dedicated output connection for transmittal to said electronic image processor; and
said means for receiving command data and for initiating control functions in response thereto comprises sampling means responsive to command bits which occur at a frequency which is an integer quotient of the frequency of said digital clock pulses, said sampling means including means for detecting command bit polarity with the occurrence of consecutive ones of said digital clock pulses during command pulses, means for comparing the command bit polarities detected, and means for generating an error signal when said means for comparing registers an unequal comparison in order to abort the performance of control functions in response to command data including any data bit in which sampling and comparison as aforesaid produces an unequal comparison.
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Abstract
An adapter is provided as an interface between a raster output scanning printer and an electronic image processor which formats digital information for use by the printer in creating printed images. The adapter accepts digital pulses through a structured array of communication lines from the electronic image processor. Each line is dedicated to the provision of certain video or control information which may be utilized by any one of a number of different raster output scanning printers. The electronic image processor is indifferent to the identity of the type of printer to which information is provided as the adapter serves to manipulate the data provided by the electronic image processor in a manner suitable to control the particular printer employed. The adapter is sensitive to the scanning cycles of the printer and accommodates deviations in scan time to increase or decrease the rate of provision of video information in accordance with fluctuations in printer motor speed. A phase lock loop with the printer motor is provided for this purpose. The adapter also multiplexes status information of operating conditions generated internally and from the printer, and serially sends this status information to the electronic image processor.
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Citations
5 Claims
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1. An adapter for interfacing a digital electronic image processor with a raster output scanning printer, said adapter having dedicated input and output connections for printer control and operation, said adapter comprising:
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means for receiving at a first dedicated input connection digital command data from said electronic image processor and for initiating control functions in response thereto; means for receiving at a second dedicated input connection digital clock signals of a predetermined uniform frequency transmitted thereto by said electronic image processor and for distributing said clock signals throughout said adapter; means for receiving in bit parallel format at a set of third dedicated input connections packets of video print information from said electronic image processor and for retiming said video information for transmission to said printer; means for monitoring the transmission of video print information to said printer and for generating data request signals at a first dedicated output connection to said electronic image processor in order to thereby request additional packets of video print information from said electronic image processor; means for monitoring the status of said adapter and said printer and for serializing status information and generating said status information at a second dedicated output connection for transmittal to said electronic image processor; and said means for receiving command data and for initiating control functions in response thereto comprises sampling means responsive to command bits which occur at a frequency which is an integer quotient of the frequency of said digital clock pulses, said sampling means including means for detecting command bit polarity with the occurrence of consecutive ones of said digital clock pulses during command pulses, means for comparing the command bit polarities detected, and means for generating an error signal when said means for comparing registers an unequal comparison in order to abort the performance of control functions in response to command data including any data bit in which sampling and comparison as aforesaid produces an unequal comparison. - View Dependent Claims (2, 3, 4, 5)
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Specification