Patent GB-832650-A (GB)
Title: Automatic silk-screen ceramic printing machine
IPC: B41F15/08
Filed: 1957-10-29
Abstract: 832,650. Stencilling apparatus; printing on curved surfaces; inking-apparatus. FERNANDEZ, J. V. Oct. 29, 1957 [Dec. 31, 1956], No. 33719/57. Class 100(2) An automatic silk-screen printing-machine for decorating ceramics comprises a squeegee operable over the stencil for forcing ink therethrough on to a transfer belt movable on rollers at opposite ends of a belt support assembly, a work-holder on a reciprocable carrier moving it to and from printing position below the lower run of the belt, means for intermittently moving the belt to bring a previously-applied ink design into position above the work, air pressure means to force the belt into the work-holder and against the work for printing, and automatic power means for effecting in sequence movement of the work-holder to printing position, forcing of the belt against the work, retraction of the work-holder, advancing of the belt, and operation of the squeegee to prepare the belt for the next cycle. The screen 167, Fig. 7, is carried on a frame 166, Figs. 7 and 16, bolted to Z-section support members 155, 159 connected at opposite ends to brackets 156, 161, the former hinged to the machine frame and the latter releasably secured to the frame by hand-screws 163, so that the screen frame can be swung up for removal of the screen or access to the transfer belt 68. Mounted on the members 155, 159 by spring bolt assemblies 175, 176 is a pressure bar 172. The belt 68 runs over rollers 66, 67 mounted by shafts 96, 100 on the frame. A belt support assembly comprises perforated plates 71, 76, vacuum and pressure chambers 72, 77 and removable end members 81, 82. A squeegee assembly 177 comprises an inverted channel member 178, squeegees 187, 188 urged downwards by springs, and end plates having holes to receive rods secured to chains 214. Ink is supplied directly to the chamber formed by the squeegees and end plates. The squeegee is driven by a reversible electric motor 55 through gears 230, 227, which are engaged when the screen frame is in operative position. The workholder 106 is secured to a carriage plate 105 operatively connected to a piston rod 139, and comprises a base plate 112, a flexible diaphragm 114, a ring 115 thereon, and a flanged member 117 supporting a resilient cushion plate 120, which together with resilient rod members 128 supports a dish 119. The plate 105 carries a rack 145 for driving the roller 67 through gears 146, 152 and a one-way clutch 153, so that the belt 68 is driven only on the rightward retracting movement of the work-holder. In operation, on depressing a foot-pedal 265 to actuate a valve 266, air is admitted to the right of a cylinder 46 to move the work-holder to printing position, and the plate 105 actuates a valve 53, whereby air is passed first through a pipe 121 to elevate the member 117 and the dish firmly against the plate 76, and then through a pipe 282 for a predetermined period to force the belt 68 down into the holder and against the dish, to transfer thereto the ink image previously formed on the belt by means of the stencil screen and squeegees. On releasing the pedal, air is admitted to the left of the cylinder 46 to retract the workholder and advance the belt, the carriage plate 105 actuating a valve 283 to release vacuum from beneath the dish and release the latter for removal. The plate 105 also actuates a valve 284 to apply vacuum below the plate 71 and hold the belt and screen firmly thereon and a switch 286 to operate the motor 55 and drive the squeegee assembly in one direction and prepare the belt for the next cycle of operations. In the following cycle, the squeegee assembly is driven in the opposite direction. Inking apparatus. To remove surplus ink from the belt 68, a roller 238 immersed in a container 236 applies a solvent to the belt. The solvent and ink is then removed by a wiping element 248, falling into a removable receptacle 249. The element 248 and roller 238 are spring-urged against. the belt.