Apparatus with beam shifting assembly means controlled to increase recording resolution

A recording apparatus comprising:

• a light sensitive recording medium;
• means for moving said recording medium in a first direction relative to a row of individually energizable light-emitting recording elements, said first direction being transverse to said row;
• a dot matrix printer including a plurality of said individually energizable light-emitting recording elements arranged in said row and generally uniformly spaced at a density of N recording elements per inch;
• means for energizing selected ones of said recording elements for generating exposure causing light emissions during each of consecutive in time line recording time periods;
• a beam shifter assembly means located within an optical path between said recording medium and said recording elements for shifting light from the selected recording elements, said beam shifter assembly means being operable in a first mode with passing of the light from the selected recording elements without substantial lateral shifting of the light for exposure of said recording medium to record pixels with the light emitted during one of said line recording time periods and for operating in a second mode with the substantial positional shifting of light in at least a lateral direction having a directional component parallel to the row of recording elements for exposure of said recording medium to record pixels with light emitted during a second of said line recording time periods that is consecutive in time to said one of said line recording time periods,
• said beam shifter assembly means including a linear polarizer means for polarizing light from the recording elements to generate beams of polarized light and electro-optic modulator means, including a PLZT modulator and a quartz layer having an optical axis oriented relative to the row of recording elements, for allowing said polarized light from the recording elements to pass through said electro-optic modulator means undeviated in said first mode and to divert said polarized light in said second mode for positional shifting in said lateral direction, said beam shifter assembly means shifting pixels recorded during one of said line recording time periods into a pixel row recorded during a different one of said line recording time periods;
• and
• control means for controlling said beam shifter assembly means to enable operation of said beam shifter assembly means in said first mode and said second mode on alternating ones of the line recording time periods of exposure to increase recording resolution of said dot matrix printer.