Patent GB-801481-A (GB)
Title: Improvements in or relating to typographical photocomposing machines
IPC: B41B27/00
Filed: 1955-01-11
Abstract: 801,481. Photographic type-composing machines. MERGENTHALER LINOTYPE CO. Jan. 11, 1955 [March 26, 1954], No. 792/55. Class 40 (3). [Also in Group XX] In a tape-controlled photographic typecomposing machine, code marks on the tape represent the character designations, their widths and the widths of interword spaces to give a justified line, signals controlled by the tape causing the selection of a desired character and determining the instant of exposure of photographic material between which and an optical projecting arrangement there is continuous relative movement. The tape also controls a number of other functions such as the selection of point size, omission of matts wrongly set up, composition without justification &c. General. A character on a preselected one of a number of font plates 54a ... 54e, Fig. 1, is selected by moving selections from two groups of shutters 57 and projected via an optical system, which provides for a number of different magnifications, to give different point sizes, and a mirror 65 and projection head 66 on a travelling carriage on to a film 67. During the composition of a line, the carriage travels continuously and the instant of exposure is determined jointly by signals from a perforated tape on which the character and justification and other signals are coded and signals from a photo-cell 73 which looks at graduations on a plate moving with the carriage for indicating its position at any instant. The controlling tape passes in succession through two reading heads at 210, 211, respectively, Fig. 17. The former; referred to hereinafter as the " scan " head, is concerned with word-space signals to give a justified line and with various control signals, e.g. to indicate that a particular line is not to be justified or contains an error and is not to be photographed, or that the point size is to be changed, or the composing operation stopped for some other reason. The latter or " read " head identifies the character to be photographed and determines the letterspacing and the word-spacing for an unjustified line. After the composition of each line, the tape is given ten steps automatically at the " read " head, to give time for the restoration of the carriage &c. before the first character signal for the next line is reached. Font plate construction, Fig. 2. The font plate 53, is friction driven by a motor 56 to bring any one of five detachable fonts 54a ... 54e into operative position and is there held by engagement of a member 83a ... 83e with a spring-urged latch 74. During the initial part of the movement, the latch is disengaged and held off by an electromagnet 90. The preliminary adjustment of the font plate in relation to the optical system is done with set-screws. Rotatable with the font plate is a contact-drum which connects a circuit corresponding to the particular font in use to a common circuit. Character-selecting shutters, Figs. 6, 8. There are eight of these each with two positions, four being movable vertically by electromagnets III, with rotary armatures, and the other four horizontally by electromagnets 113. Perforations are arranged so that for any setting of the shutters there is only one light-path through the shutters. Movement is guided by slotted blocks 102, 102a. Selecting size of projected image. Six sizes are provided for and selection is effected by moving the rear component 62, Figs. 1, 10, of a pair of lenses by a rack and pinion to one of six positively located positions and selecting the forward member of the pair from six turretmounted lenses 63a ... 63f. Projection carriage, Figs. 10, 11. This travels on ball-bearings formed by balls 150 in cages 151 co-operating with V-section channels in the base 117 and the carriage and is driven continuously backwards and forwards by a rack and pinion gear 172, 186. 176 coupled to a constantly running motor by clutches controlled by limit switches, the forward speed being adjustable. It is held to the base by spring-pressed rollers 154a . . . 154d at each corner. The driving rack moves in a guide and is coupled to the carriage by a universal joint 175. Optical system, Fig. 16. Light from a source passes via a condenser, the selected character and an individual collimating lenslet to an imaging lens and thence via a pair of lenses arranged like an eyepiece and governing the magnification to a mirror and projection lens system on the movable carriage. Since the exit pupil of the imaging system cannot coincide with the principal plane of the projecting system in all positions of the carriage it is made to do so in the mid-position. Tape-reading arrangements, Figs. 17, 19. The tape on grooved drums is driven past two reading heads by separate step-by-step motors. The perforations cause normally-open switches 232, 233 to be closed by a spring 234 by permitting teeth 236 of a wheel 255 on a pivoted arm 230 to penetrate to the corresponding groove in the drum. The tape, guided by arcuate members 240 is driven by teeth at the sides of the drums. Preliminary operations. The beginning of the tape is punched with two " end of line " signals separated by ten blanks. With a tape in position, S1 is closed and when the power is switched on, relays SSA, SSAX, Fig. 24, pull up and interact with the " scan " head stepping- magnet SHSS until the second " end of line " signal is in the reading position, relays 1Q, 2Q and 4Q then pull up and energize relay SEL which holds SSA to suspend the stepping action and releases a normally energized relay V1. On the operation of push-button S2, relay RRA and " read " head stepping-magnet RHSS interact until the first "end of line signal " is in reading position, whereupon relays 1RFD, 2RFD and 4RFD, Fig. 22, pull up and energize relay REL to open the driving circuit. With REL and SEL both operated, magnet L9 is operated to step the film on one line. Homing circuits are made, if necessary, for switches QSS, QRSS, the settings of which during line composition determine the word spacing for a justified line, and when both have reached normal, relay SE pulls up and locks and releases SSA which is followed by SSAX and (reverse-drive) stepping magnet SHSS. The tape at the " scan " head is thus advanced by one step, releasing the Q relays. SE also releases REL, SEL. With Jl back and none of the relays Q, QR operated, circuits exist for QQR, QRS and QS, Fig. 25, and SE is unlocked. JI re-operates, releasing QS, QRS. Capacitor Q1. which was charged on the operation of SE, now discharges through relay I which gives an impulse to a forward drive (ten-point) switch ISSS. The latter on moving'off normal changes over contacts ISSS3, whereupon relay ISS pulls up and continues to interact with ISSS until the latter reaches its home position and contacts ISS2 are restored. At each step, an impulse is sent to magnet RHSS to step on the tape at the "read " head. After the steps, ISSS is again in its normal position and the second " end of line " signal is in position at the " read " head. Meanwhile, as a result of the relapse of SE and SSA, SSAX and SHSS interact to bring the third "end of line" signal into reading position at the "scan" head. Registering justification signal. With REL, SEL operated, SE pulls up as before, to cause one step of the tape at the " scan " head by the release of SSA. The justification signal now in position energizes a selection of relays 1Q ... 4Q and 1QR . . . 5QR and these mark terminals in the banks of switches QSS, QRSS which, with SE operated, proceed by selfinterruption until they reach the marked terminals over which the driving magnets are short-circuited. QS, QRS operate over the marking circuit and as before, SE is unlocked; JI releases QS, QRS, switch ISSS is stepped round sending driving impulses to RHSS and simultaneously SHSS steps the tape at the " scan " head until the next " end of line " signal energizes SEL. In its set position, Q circuits representing in binary notation the required width of each space if the additional space units available are divisible without remainder by the number of spaces in a line, i.e. the normal space of 3 units + the appropriate fraction of the additional space. Where, however, there is a remainder, the position of QSS represents 3 units + the quotient + 1 unit and QRSS is set to a position short of its last terminals by the value of the remainder. Each space signal, during the composition of a line, operates relay 2RFD, Fig. 22, only and on the operation of MF, Fig. 29, which takes place at the same time as the pressing of the preceding character; QRA is operated to energize the stepping magnet QRSS momentarily and cause the switch to step on. When it reaches its home position, capacitor QQSU is disconnected from a charging circuit and connected to relay QSU which gives an impulse to the stepping magnet of QSS. In the new position, QSS registers a number one less than that previously registered and this number determines the remaining space widths. Control by character signals; justification. When ISSS reaches normal after the registration of the justification signal the first " character " code marking is in position on the " read head. Push-button S38, Fig. 26, having been operated, relay ST is locked energized and clutch FC is operated to drive the projection carriage in the forward direction. The first photo-electric impulse causes an electronic counter (not described) to trigger a pair of flip-flop circuits TSHD, TSHE, Fig. 29. These circuits have different time constants so that anode relay SHD which releases any operated shutter-control relays SSH, Fig. 22, falls back in time to allow a momentary circuit to be made for these relays via tape-operated contacts s3 . . . s10 and front contacts of SHE. The relays SSH lock up and operate the appropriate shutters L1 . . . L8. When TSHE returns to its stable state, a further flip-flop circuit TRHA is triggered to give a momentary operatio