GB1263031A - Photocopying machine - Google Patents

Abstract

1,263,031. Photo-copying machines. OC•- VAN DER GRINTEN N.V. June 24, 1970 [June 24, 1969], No.30598/70. Heading G2A. In a photo-copying machine in which the copy material is conveyed continuously through the exposure station at a speed which can be varied, and is exposed to a printing light whose intensity can also be varied, a single control member is provided which can adjust either variable (speed or intensity) while the other remains constant. As shown, the single control member is a spindle 2 with an operating knob 1, which spindle carries the sliding arms 3, 4 of respective potentiometers 5, 6. Half of potentiometer 5, which controls the speed of movement of the copy material, is short circuited by a connection 15, and the opposite half of potentiometer 6, which controls the intensity of the light, is short circuited by a connection 16. Initially, spindle 2 is rotated anti-clockwise as far as it will go, and this is the starting position. When spindle 2 is now turned clockwise, the output voltage from potentiometer 5 gradually increases as arm 3 moves from terminal 8 to terminal 10, while the output voltage from potentiometer 6 remains constant as arm 4 moves over the short circuited part from terminal 12 to terminal 14. Thus the speed of movement of the copy material is increased from a minimum to a maximum value while the light intensity remains constant. With further clockwise rotation of spindle 2, the speed remains at this maximum value while the light intensity is reduced from its maximum value to zero. In the embodiment of Fig. 3 (not shown) the same result is obtained by a mechanical arrangement, in which a central shaft (25) is connected by gearing alternately to one or the other of two adjacent shafts (30, 31) which are connected to means for varying speed and intensity respectively.