US 4,254,439 A · Facsimile mid-page restart

Abstract

The method and apparatus shown herein provide for restarting a facsimile operation after a mid-page interrupt without overlapping or splitting the image. Furthermore, this is accomplished in a facsimile system that does not have a one-to-one synchronous relationship between synchronized mechanisms in the system. In operation, a print carriage is synchronized to a false once-around signal related to the motion of a print drum. There is a predetermined cyclic relationship between the false once-around and the real once-around for the drum. If a mid-page interrupt occurs, the line position at the time of interrupt is remembered, and the particular relationship existing between the false once-around and the real once-around at the time of interrupt is remembered. The carriage is backed up to a point prior to the mid-page interrupt and rests until restart. Upon restart, the carriage is accelerated up to speed and resynchronized to the false once-around before it reaches the point of interrupt. The once-around to which the carriage is resynchronized has the same relationship to the real once-around as stored at the time of interrupt. When the carriage reaches the interrupt point, that position is detected, and the facsimile system resumes printing on the next line without splitting or overlapping the image.

Claims23

Dependent claims

In a facsimile system, apparatus for restarting a scanning carriage in the middle of scanning an image without overlapping or splitting the image when the scan operation is interrupted and restarted, said apparatus comprising:

means for generating false, line reference signals having a fixed frequency relationship to the actual line reference signals for the image being scanned;
means for synchronizing the movement of the carriage to the false, line reference signals;
means for storing the synchronization conditions existing at the time of the interrupt;
and
means connected to said storing means for resynchronizing the carriage upon restart to the synchronization conditions stored by said storing means at the time of interrupt.

2 more elements

In a facsimile system having a linearly moving print head and a rotary print drum resynchronization apparatus for the print head drive to restore the print head, after an interrupt, to the same operative conditions with the print drum at the next print position occurring after the position last printed when the interrupt occurred, said apparatus comprising:

means for generating a fake once-around signal having a fixed frequency relationship to the real once-around for the print drum;
means for dividing the read once-around into an integer number of reference positions within each real once-around;
means for synchronizing said print head drive to said fake once-around signal so that the movement of the head has a known relationship to the real once-around;
means connected to said dividing means for storing the relationship between the fake once-around signal and the real once-around at the time of interrupt;
and
said synchronizing means connected to said storing means for synchronizing upon restart, said print drive to a reset fake once-around signal, said reset fake once-around signal has the same relationship to the real once-around that existed between the fake once-around signal and the real once-around during the interrupt whereby the print head returns to the same operating condition for restart that existed at the time of interruption.

3 more elements

Dependencies are inferred from the claim text.

Facsimile mid-page restart

Life of this patent

Facsimile mid-page restart

Life of this patent

Abstract

Claims23