Synchronizing signal generating system for laser scanner

A synchronizing signal generating system for a laser scanner, said synchronizing signal generating system comprising:

• first means for emitting a first laser beam for scanning and a second laser beam for synchronization of scans by said first laser beam;
• second means for scanning a medium by said first laser beam;
• third means for scanning a grating by said second laser beam, said grating having bright portions and dark portions alternately arranged along a scanning direction of said second laser beam;
• a converging optical system for converging said second laser beam transmitted through said grating;
• a light receiving system for receiving said second laser beam converged by said converting optical system and for generating a synchronizing signal;
• and
• fourth means for controlling said first means responsive to said synchronizing signal so as to synchronize a scan timing of said first laser beam,
• said converging optical system comprising a mirror array made up of a plurality of concave mirrors, said mirror array being provided for a length corresponding to a scan length of said second laser beam on said grating,
• a ratio Pm/Pg between a pitch Pm of said concave mirrors and a pitch Pg of the bright and dark portions of said grating being set to an integer, so that said second laser beam transmitted through said grating is prevented from scanning a junction portion between two mutually adjacent concave mirrors of said mirror array.

A synchronizing signal generating system for a laser scanner, said synchronizing signal generating system comprising:

• first means for emitting a first laser beam for scanning and a second laser beam for synchronization of scans by said first laser beam;
• second means for scanning a medium by said first laser beam;
• third means for scanning a grating by said second laser beam, said grating having bright portions and dark portions alternately arranged along a scanning direction of said second laser beam;
• a converging optical system for converging said second laser beam transmitted through said grating;
• a light receiving system for receiving said second laser beam converged by said converting optical system and for generating a synchronizing signal;
• and
• fourth means for controlling said first means responsive to said synchronizing signal so as to synchronize a scan timing of said first laser beam,
• said converging optical system comprising a mirror array made up of a plurality of concave mirrors, said mirror array being provided for a length corresponding to a scan length of said second laser beam on said grating,
• a ratio Pm/Pg between a pitch Pm of said concave mirrors and a pitch of the bright and dark portions of said grating being slightly greater than an integer, so that said second laser beam transmitted through said grating is prevented from scanning a junction portion between two mutually adjacent concave mirrors of said mirror array.

A synchronizing signal generating system for a laser scanner, said synchronizing signal generating system comprising:

• first means for emitting a first laser beam for scanning and a second laser beam for synchronization of scans by said first laser beam;
• second means for scanning a medium by said first laser beam;
• third means for scanning a grating by said second laser beam, said grating having bright portions and dark portions alternately arranged along a scanning direction of said second laser beam;
• a converging optical system for converging said second laser beam transmitted through said grating;
• a light receiving system for receiving said second laser beam converged by said converting optical system and for generating a synchronizing signal;
• fourth means for controlling said first means responsive to said synchronizing signal so as to synchronize a scan timing of said first laser beam;
• and
• signal generating means for generating a pseudo synchronizing signal,
• said converging optical system comprising a mirror array made up of a plurality of concave mirrors, said mirror array being provided for a length corresponding to a scan length of said second laser beam on said grating,
• said fourth means comprising a phase locked loop circuit for generating an image clock signal responsive to said synchronizing signal, said image clock signal having a frequency higher than that of said synchronizing signal, and driving means for driving said first means in synchronism with said image clock signal depending on input information data.

A synchronizing signal generating system for a laser scanner, said synchronizing signal generating system comprising:

• first means for emitting a first laser beam for scanning and a second laser beam for synchronization of scans by said first laser beam;
• second means for scanning a medium by said first laser beam;
• third means for scanning a grating by said second laser beam, said grating having bright portions and dark portions alternately arranged along a scanning direction of said second laser beam;
• a converging optical system for converging said second laser beam transmitted through said grating;
• a light receiving system for receiving said second laser beam converged by said converting optical system and for generating a synchronizing signal;
• fourth means for controlling said first means responsive to said synchronizing signal so as to synchronize a scan timing of said first laser beam;
• and
• correcting means for correcting a duty cycle of said synchronizing signal and for outputting a corrected synchronizing signal,
• said converging optical system comprising a mirror array made up of a plurality of concave mirrors, said mirror array being provided for a length corresponding to a scan length of said second laser beam on said grating,
• said fourth means comprising a phase locked loop circuit for generating an image clock signal responsive to said corrected synchronizing signal, said image clock signal having a frequency higher than that of said synchronizing signal, and driving means for driving said first means in synchronism with said image clock signal depending on input information data.

A synchronizing signal generating system or a laser scanner, said synchronizing signal generating system comprising:

• first means for emitting a first laser beam for scanning and a second laser beam for synchronization of scans by said first laser beam;
• second means for scanning a medium by said first laser beam;
• third means for scanning a grating by said second laser beam, said grating having bright portions and dark portions alternately arranged along a scanning direction of said second laser beam;
• a converging optical system for converging said second laser beam transmitted through said grating;
• a light receiving system for receiving said second laser beam converged by said converting optical system and for generating a synchronizing signal;
• fourth means for controlling said first means responsive to said synchronizing signal so as to synchronize a scan timing of said first laser beam;
• signal generating means for generating a pseudo synchronizing signal;
• and
• selector means for selectively outputting one of said synchronizing signal and said pseudo synchronizing signal so as to output a continuous synchronizing signal,
• said converging optical system comprising a mirror array made up of a plurality of concave mirrors, said mirror array being provided for a length corresponding to a scan length of said second laser beam on said grating,
• said fourth means comprising a phase locked loop circuit for generating an image clock signal responsive to said continuous synchronizing signal, said image clock signal having a frequency higher than that of said synchronizing signal, and driving means for driving said first means in synchronism with said image clock signal depending on input information data,
• said synchronizing signal being generated during a scan duration in which said medium scanned by said first laser beam and no synchronizing signal being generated during a non-scan duration in which no scan of said medium is made by said first laser beam,
• said signal generating means generating said pseudo synchronizing signal during said non-scan duration, said pseudo synchronizing signal having a predetermined frequency identical to that of said synchronizing signal.