Contact printing method and apparatus

In a contact printing method wherein an original and a light-sensitive material are placed in superposition in a vacuum chamber, the improvement which comprises:

• (a) defining the vacuum chamber between a light-transmitting plate and a diaphragm, at least the diaphragm being elastic, the original and light-sensitive material being placed in the vacuum chamber with the original disposed closer to the light-transmitting plate;
• (b) providing a second vacuum chamber disposed opposite to the first recited vacuum chamber across the diaphragm;
• (c) providing a third vacuum chamber disposed opposite to the first vacuum chamber across the light-transmitting plate;
• (d) evacuating the first, the second and the third vacuum chambers simultaneously;
• (e) causing the light-transmitting plate and the diaphragm to press the original and the light-sensitive material into close, uniform contact with each other by introducing atmospheric pressure into the second and the third vacuum chambers;
• and
• (f) exposing the light-sensitive material to light through the light-transmitting plate and the original.

In a continuous contact-printing method wherein a vacuum chamber is formed between a light-transmitting plate and an elastic diaphragm, and wherein an original is attached to the inside surface of the light-transmitting plate, the improvement which comprises:

• (a) providing a second vacuum chamber disposed opposite to the first recited vacuum chamber across the diaphragm;
• (b) stretching a continuous strip of light-sensitive material through the first vacuum chamber;
• (c) evacuating the first and the second vacuum chambers simultaneously;
• (d) causing the diaphragm to press the light-sensitive material into close, uniform contact with the original on the inside surface of the light-transmitting plate by introducing atmospheric pressure into the second vacuum chamber;
• (e) exposing the light-sensitive material to light through the light-transmitting plate and the original;
• (f) causing the diaphragm to release the light-sensitive material by introducing atmospheric pressure into the first vacuum chamber;
• (g) feeding a fresh length of the light-sensitive material into the first vacuum chamber;
• and
• (h) repeating the cycle of steps (c) to (g).

In a contact printing apparatus of the type having a vacuum chamber formed between a light-transmitting plate and an elastic diaphragm for accomodating an original and a light-sensitive material in superposition, the improvement comprising:

• (a) means for defining a second vacuum chamber disposed opposite to the first recited vacuum chamber across the diaphragm;
• (b) means for evacuating the first and second vacuum chambers simultaneously;
• and
• (c) means for introducing thereafter atmospheric pressure into the second vacuum chamber, whereby the original and light-sensitive material in the first vacuum chamber can be urged into close, uniform contact with each other by first simultaneously evacuating the first and second vacuum chambers and then by introducing atmospheric pressure into the second vacuum chamber.

In a continuous contact-printing apparatus of the type having a vacuum chamber formed between a light transmitting plate and an elastic diaphragm, with an original attached to the inside surface of the light transmitting plate, the improvement comprising:

• (a) means for defining a second vacuum chamber opposed to the first recited vacuum chamber across the diaphragm;
• (b) means for defining a hermetically sealed payoff chamber and takeup chamber on the opposite sides of and in constant communication with the first vacuum chamber;
• (c) means for feeding a continuous strip of light-sensitive material from the payoff chamber to the takeup chamber through the first vacuum chamber;
• and
• (d) means for evacuating the first and the second vacuum chambers.