Transmission of encoded facsimile signals at variable intervals commensurate with recording time

Claim 1

A facsimile communication system including, at a transmitter station, means for successively scanning along each of a plurality of line paths within a document to generate a binary signal waveform comprising binary digits at one of first and second binary levels corresponding to the light levels of said document, means for coding the run-length of each binary digit in said waveform into a corresponding digital code for transmission to a receiver station, and at said receiver station, means for decoding the digital codes to recover the original binary signal waveform, and a plurality of energy transfer elements for transferring electrical energy to the surface of a recording medium, said elements being successively arranged along a line path and equally divided into a plurality of groups, the elements of each group being electrically connected together so as to be energizable for simultaneous transfer of energy within a predetermined period of time, said system comprising, at said transmitter station: means for equally dividing said binary signal waveform into a plurality of data blocks equal in number to said groups of elements to detect significant data blocks in each of which at least one binary digit at said first binary level occurs; means responsive to the start of transmission of said digital codes for measuring data blocks by needed for recording said significant data blocks by multiplying said predetermined energizable period by the number of said detected significant data blocks to cause said scanning means to proceed to the next line path at the end of said measured time interval; and at said receiver station, means for equally dividing the recovered binary signal waveform into a plurality of data blocks identical to the data blocks at said transmitter station to detect said significant data blocks; and means for selectively simultaneously energizing a group of said energy transfer elements with the binary digits of said detected significant data block so that groups of said energy transfer elements corresponding to insignificant data blocks in which binary digits are entirely at said second binary level are skipped without loss of time.