Accurate master positioning for graphic copier - using electron elements at correct height for focussing and thus avoiding parallax errors

摘要

The positioning arrangement can be used in multiple colour systems requiring successive masters for different colours to be used. This is achieved with reduced cost and greater convenience than with conventional systems. A number of adjustment lenses (3) mounted on a rail or rod (1) can be moved in their longitudinal direction between erection elements (2) on the rod or rail ends. The height of the erection elements is chosen to ensure that the necessary lens focussing arrangement can be achieved in each adjustment position. A T- section or crossed section rail or rod may be used. This enables positioning points to be fixed in each plane through the adjustment lenses.