Patent GB-488726-A (GB)
Title: Improvements in or relating to series printing machines
IPC: B41L47/58
Filed: 1937-01-27
Abstract: 488,726. Photo-electric control of printing-machines. JACKSON, L. MELLERSH-. (Addressograph- Multigraph Corporation) Jan. 27, 1937, No. 2422. [Class 40 (iii)] [Also in Group XVI] Relates to printing-machines in which printing devices are moved successively through a guideway, and each device is provided with identifying or classifying means, located in predetermined positions, to effect selective control of the machine through the agency of a light beam acting on a light-sensitive device. According to the invention, means having a permanent predetermined formation are arranged in the machine to co-operate with the classifying means on the printing devices, to permit or intercept the passage of light to the light-sensitive means influencing the operation of the machine. Two particular applications of the invention are described and illustrated. The invention is shown in Figs. 2, 3, and 5 as applied to an address-printing machine for the purpose of enabling selected printing plates to be skipped (i.e. to be inoperative). The plates D are fed intermittently from a magazine M into printing position under a platen P, Fig. 2, by means of chains 31 engaging with sprockets 29. One of the sprockets is driven by a pawl 26 carried by a rocker 25 which is operated by a shaft 20 through an eccentric 21 and connecting rod 23, Fig. 3. The platen is carried by an arm 32 of a rocker 33 pivoted at 34, the rocker 33 having arms 35, 36 with rollers engaging cams 39, 40 fast on a sleeve 41 surrounding the shaft 20. Connection between the sleeve and the shaft is made, when the platen is to operate, by a clutch comprising a disc 42 on the shaft, carrying a spring-actuated pawl 43 coacting with a lug 46 on the sleeve 41. The sleeve is disconnected from the shaft when an arm 47 engages the tail of the pawl. Before reaching the printing position, each printing plate D is brought under a casing 82 containing an optical system which projects a beam of light on to a photo-electric cell 84. Each plate is provided with classifying means which, when the plate is below the casing 82, is adapted to co-operate with a device 80 of fixed predetermined formation, located at the bottom of the casing, to control the passage of light to the cell. As shown, the classifying means consist of tabs T, Fig. 5, projecting from selected positions on the plate D, and the device 80 consists of an opaque strip having apertures formed therein in selected positions corresponding to certain positions which the tabs T may occupy. When a plate D is below the casing 82, and has no tabs thereon below the openings in the device 80, light passes to the cell 84. The cell is so connected to a gridcontrolled discharge tube, in circuit with a relay, that when light falls on the cell the relay causes a magnet 77 to be energized. The armature 76 of the magnet thereby operates mechanism which positions the arm 47 in the path of the pawl 43, so that the sleeve 41 does not turn with the shaft 20 when the plate D that has just been tested moves into printing position, and the platen P is not operated. Thus, only the plates which are tabbed to correspond with the formation of the device 80 are used for printing and the rest are " skipped." Alternatively, the opposite effect may be produced. This may be done mechanically, by adjustment by means of an eccentrically-mounted knob 71, Fig. 3, of the position of a segment 65 which controls the clutch-actuating arm 47, or it may be effected by means of a switch which changes the connections between the photo-electric cell and the glow discharge tube. In each cycle of the machine during which printing normally occurs, a rod 56 is moved upwardly by the connecting rod 23, and restores the arm 47, when necessary, to the position in which it allows the clutch to operate the platen. The lamp L in the photo - electric device may be lit only at the time when a printing plate is being tested, or the current supply to the cell and discharge-tube may be controlled by a timing switch which closes the circuit only when required. This switch may consist of contacts 113, Fig. 3, operated by a lug 114 on the rocker 25. Fig. 8 shows means for applying the invention to the control of a device such as is shown in U.S.A. Specification 1,299,437, for separating the printing plates, after use, into selected receptacles, so that all the printing plates that are to be used again are separated from the others. In this arrangement, the plates pass from the anvil A into a shoot 160 provided with a pivoted gate 161 which, according to its position in the shoot, directs the printing plates either down a branch 162 into a tray 163 or down a branch 160<1> into a tray 164. The gate is operated by mechanism including a cam which is coupled to a rotating shaft by a clutch under the control of an electromagnet. Normally, when a printing plate reaches the shoot 160, the gate 161 lies in the position shown, and the plate passes into the tray 163. If, however, the magnet has been energized as a result of the control of the light beam in the detector by a tab in a predetermined position on the printing plate, the gate 161 is swung over to the right, and the plate passes down to the tray 164. Fingers 166, 168 on a pivoted frame 165, operated in timed relationship with the delivery of the printing plates, pack the plates together in the trays. British Specifications 372,337, 375,113, 377,868, and 453,535, [all in Group XVI], also are referred to.