Patent GB-1332481-A (GB)
Title: Microfilm printer
IPC: G06K15/12
Filed: 1970-10-06
Abstract: 1332481 Photographic type composing apparatus MEMOREX CORP 6 Oct 1970 [6 Oct 1969] 47497/70 Heading B6W [Also in Division G2] In apparatus for recording the output from a computer on a microfilm 40, there is provided means for advancing the film after each line of output has been recorded; a first optical system, formed by a scanning shutter wheel 34, a mirror 36 and lens 46, for imaging the output on to one side of the film; and a second optical system, formed by a lens 46, for imaging a form 24 on to the other side of the film, the second optical system being operated after a predetermined number of lines have been imaged on the microfilm. Character generation (Fig. 9).-A matrix of optical fibres 174 is connected to a character display line 176 and to a bank 178 of light emitting diodes, the fibres being arranged to give groups of thirty-five fibres in the line 176, the groups in turn being arranged in sets. Corresponding fibres in each set are connected to the same diode in the bank 178 so that every fourth character in the line 176 is the same. The shutter wheel 34 contains apertures 180, each corresponding in width to three groups. Thus as three groups of a set are being imaged on to the microfilm, the fourth group is altered, thereby building up the output line image. The slots 180 are spaced so that when one has just passed the line 176, the next slot is about to start scanning the line 176. After a whole line image has been formed on the microfilm, a signal is passed to microfilm advance mechanism to advance the film one line.  Line advance mechanism (Fig. 6).-The film is advanced a line at a time by an incremental drive capstan 50, the operation of which is controlled by two magnetic particle clutches, one acting as a brake 132 and the other as a clutch 148 selectively connecting the capstan shaft 120 to a drive belt 116. Initially, the current in the clutch assembly 148 is high enough to align the magnetic particles therein, but the driving force is lower than the braking force applied by the brake 132. In response to the above mentioned signal, the current to the brake 132 is shut off. so that the shaft 120 is driven. The brake current is increased again so that partial realignment of the magnetic particles takes place, and the brake is ready to operate as soon as current to the clutch is reduced. The line advance mechanism may be instructed to advance the film by an integral number of line spacings. The shaft 120 carries an apertured disc 156 which is arranged to transmit a pulse to a photodetector 160 which thereby acts as a line counter. After a predetermined number have been counted, the form 24 is imaged on to the microfilm, so that, after development, the film displays data ehtered in a form. Film transport mechanism (Fig. 1).-A supply capstan 48 and a take-up capstan 52 are provided in addition to the capstan 50, there being tension rollers to maintain the film under tension around the capstans 48, 52. Motors are provided to drive these two capstans and rotate shafts in film supply and take up magazines 56, 58. The motors are controlled by switches which operate to maintain, within predetermined limits, the quantities of film between capstans 48, 50 and between capstans 50, 52. The total footage of film passing through the apparatus may be counted.