JPS6442243A - Density correction in optical scan recording - Google Patents

Abstract

PURPOSE:To prepare a suitable conversion table by accurately measuring a density, by a method wherein an output signal level of a photodetector when measuring light emitted from a light source is irradiated and the output signal level when the light source is not lighted are obtained, and whether both are respectively not less than a specific level or not more than the specific level is determined. CONSTITUTION:An operation circuit 51 stores an output level L1 when a light source 29 is lighted and an output level L2 when the light source 29 is put out, and whether the output level is not more than a specific value or not is judged. When 'NG' indication is shown, performances of the light source and a photodetector 30 are examined, and when deteriorated, they are replaced by normal ones. When a shading member 50 is failured, it is repaired, and the light source 29 is again lighted and put out. An indication of an indication part 52 at that time is observed. When this indication shows 'OK' or the like, density measurement of density patterns PT1-PTn becomes under a state capable of being correctly performed under an enough dynamic range. Therefore, sensitizing materials 16 having recorded the density patterns PT1-PTn are appropriately hereinafter sent to a density measuring part 28, and an operation that a conversion table T is prepared, is carried out.