Abstract: The disclosed apparatus automatically retrieves desired information on an information bearing medium having information and marks. In the retrieving apparatus, the marks are detected and counted during the feed of the information bearing medium. In accordance with the number of the counted marks, the feeding of the data bearing medium is controlled to retrieve the desired data. The apparatus is provided with at least three mark-detecting means for successively detecting the mark and memory means for memorizing the detections of the mark by the respective mark-detecting means, and a mark counting signal is formed from the content in said memory means and the counting signal is counted in order to eliminate the possibility that one and same mark may erroneously be counted twice or more when the feeding speed of the information bearing medium is abruptly changed.

Abstract: An image forming apparatus has a reciprocatingly movable member for forming an image on a record medium. The reciprocatingly movable member is moved and set to a predetermined home position before a first image is formed. A sensor is associated with the moving and setting operation of the reciprocatingly movable member. An error is detected if the sensor does not sense within a predetermined time which is clocked in synchronism with a control means.

Abstract: The present invention provides a retrieving apparatus for retrieving desired information contained in a film making use of retrieval marks recorded on the film. The retrieving apparatus is useful for many different types of films having retrieval marks recorded in different marking modes. The retrieving apparatus comprises mark detector exchangeable according to the marking mode, a device for generating a coded signal corresponding to the exchange of mark detector and a display for making a display of the type of film usable in the apparatus in the present state of exchange of mark detector in response to the coded signal.

Abstract: A light quantity controller and an input device are disclosed. The light quantity controller comprises a light source, a photo-sensor to detect a light quantity of the light source, a signal source for generating a reference signal, a comparator for comparing the detected light amount with the reference signal, and control circuit to control a duty ratio of the energization to the light source in accordance with the compare result to maintain the light quantity of the light source at a constant level. The light quantity controller further comprises a comparator to compare the energization signal to the light source with a reference signal to detect the degradation of the light source. The input device has a key matrix including a plurality of input ports and a plurality of output ports of a control unit interconnected through switches. A signal source independent from the output ports of the key matrix is connected to at least one of the input ports through switches.

Abstract: One of several corona dischargers used in an electrophotographic apparatus is connected to a power source transformer so as to selectively operate these corona dischargers. The power source transformer is provided with a tertiary winding, to which a switching device is connected. When the switching device is turned on, a secondary output from the transformer becomes lower than a corona discharging limit voltage, whereby the corona discharging stops.