PURPOSE: To permit printing of 1:1 reverse characters and boldfaced characters without using a ND filter by changing over the quantity of light of a non- electrode lamp for printing so as to change the quantity of the light in the case of bringing an original and photosensitive material into tight contact with each other and printing said material and in the case of holding a spacer in place between the original and the photosensitive material and printing the photosensitive material.

CONSTITUTION: The quantity of light of the non-electrode lamp for printing is changed over so as to be changed in the case of bringing the original and the photosensitive material into tight contact with each other and printing said material and in the case of holding the spacer in place between the original and the photosensitive material and printing the photosensitive material. More pacifically, the supply electric power is decreased in the case of executing the 1:1 reverse. The supply of the electric power is increased to change the quantity of light of the non-electrode lamp 20 for printing in the case of forming the boldfaced characters. The adequate printing of the 1:1 reverse and boldface characters is thereby executed by changing the quantity of the light without using the neutral density filter (ND filter).