Abstract: Method for measuring the bearing play in a highly dynamic mechanical transmission chain between a setting member and a functional member on which it acts, wherein a control unit actuates the setting member with a square-shaped desired signal of at least half a period and a measuring device is provided with a sensor for sensing the position of the functional element measures its distance from a reference point of the functional element, and the bearing play is determined from the comparison of the actual deflection with the command signal of the setting member.

Abstract: A photographic copying machine wherein copying light which issues from a light source and is directed toward an original is caused to pass through a light intensity weakening shutter of the venetian blind type. The shutter is adjusted to change the rate of passage of light therethrough in dependency on the intensity of signals which are generated by the exposure control system of the copying machine and denote the anticipated exposure times in the red, green and blue colors. If the anticipated exposure times are too short, the intensity of copying light which impinges upon the copying material is reduced by a stepwise adjustment of the venetian blind type shutter. Inversely, the shutter is caused to permit the passage of more light if the signals which are generated by the exposure control system denote a relatively long exposure times in the three colors.

Abstract: Apparatus for collecting webs of photographic paper issuing from a photographic copying machine has a magazine which is attachable to the copying machine and contains a wheel having a slotted periphery for introduction of the leader of a web by way of a channel defined by a guide which is pivotably mounted in the magazine. The channel extends radially of the wheel during introduction of the leader so that the latter can enter the interior of the wheel. The wheel is thereupon driven to convolute the web about it periphery and to automatically propel the guide to a position in which the channel is tangential to the wheel. The guide is then intercepted and held against pivotal movement in a direction to locate the channel radially of the wheel, and the guide has a roller which rests on the outermost convolution of the roll of paper which accumulates on the wheel.

Abstract: The variation in transparency along the surface of an original is detected and a corresponding transparency-indicating signal is generated. The spectral components of the transparency-indicating signal having frequencies above a predetermined frequency associated with sharp images are integrated to form an integration signal corresponding to the time integral of these higher-frequency spectral components. The determination of whether the original bears an image whose sharpness warrants copying of the original is made by comparing the integration signal against a reference signal.