Automatic masking device

A masking device for covering, when an image of an original is to be exposed on a photosensitive material, an area which is not to be exposed of said photosensitive material, comprising:

• a light transmitting plate having a pair of end portions in a first direction and a pair of end portions in a second direction intersecting said first direction provided on said original;
• a pair of first light intercepting means, each said first light intercepting means having one end thereof fixed near an end portion of said first direction of said plate for covering said plate from both sides in said first direction,
• each one of said first light intercepting means including a first cover for covering said plate and means for determining an end portion of said first cover in the first direction,
• each of said means for determining an end portion in the first direction including a first cover holding means for holding said end portion of the corresponding first cover, and means for defining an opening portion in the first direction arranged close to said plate,
• a first space existing between said first cover holding means and the associated means for defining an opening portion in said first direction;
• and
• a pair of second light intercepting means, each of said second light intercepting means having one end fixed near an end portion thereof in said direction of said plate, for covering said plate from both sides in said second direction,
• each one of said second light intercepting means including a second cover for covering said plate and means for defining an end portion of said second cover in said second direction,
• said means for defining an end portion in the second direction including a second cover holding means for holding said end portion of said cover and means for defining an opening portion in the second direction,
• at least part of said means for defining an end portion in the second direction being near said means for defining an opening portion in said first direction located in said first space.