GB1147363A - Improved method and apparatus for handling freshly-printed sheets - Google Patents

Abstract

1,147,363. Finishing printed paper; sheet delivery. MILLER PRINTING MACHINERY CO. 5 Oct., 1966 [8 Oct., 1965(2)], No. 44443/66. Headings B6C and B6H. A method of conditioning sheets freshly printed with ink comprises first applying heat and then cooling and humidifying the sheets during their continuous transfer from a printing unit to a delivery unit. Figs. 1a, 1b and 1c taken together constitute a side elevational view of apparatus according to the invention; sheets -printed between the impression cylinder 3 and the blanket cylinder 5 of an offset press are taken by transfer cylinder 6 and are then gripped by the gripper bars of a sprocket chain 11 which is trained about sprockets 12 and 13 and guided by guides 14, 15 and 16. The sheets are carried by the composite endless element 11a, comprising the chain 11 and the grippers, between an infra-red dryer 17 and reflector 18 to promote setting of the ink and volatilize any volatile constituents of the ink: the paper then passes upwards through a gas dryer 19 in which flames 19a, directed against the faces of the paper, set the ink and burn the remaining volatile constituents, any residue being removed by air knives 20. The endless element 11a then carries the paper around chill roller 8; the element is cooled by spraying with water in a chamber 21a, and then dried by air jets 21c. The paper is carried in turn about parts of further chill rollers 22, 23 equipped with grippers for the sheet and moistened by conventional damping apparatus including fountains 24. Individual sheets may be removed for inspection along shoot 59 (Fig. 8, not shown) Sheet delivery.-Suckers 63 connected to a vacuum line 65 in rotating arms 157 take sheets from the chill roller 23 and transfer them to one of a series of reciprocating suckers 66. Mounted in the supporting structure for continuous movement are a number of endless sprocket chains 89 carrying gripper assemblies 96a, the chain being guided by channels 94 and 95. Each gripper assembly 96a grips the leading edge of a sheet held by reciprocating suckers 66, the suction is then cut off. and the sheet is transferred and is swung into generally face-to-face relationship with the next sheet before being carried by chain 89 through a chamber 110 in which humidifying or, if necessary, dehumidifying is carried out. The grippers then release the sheets which fall in turn on to a pile support 111. Each gripper assembly 96a is illustrated in Fig. 3; rollers 101 and 105 are controlled by cam grooves 108 and 120 and thus orientate the grippers correctly for receiving sheets from suckers 66; outside the field of these grooves, the weight of the assembly causes them to assume positions B and C indicated in Fig. 1a. with the gripper 98 and the gripper pad 103 extending straight downwards and generally kept in contact with each other by coil spring 106 except when roller 101 rides up on cam 109 (Fig. 1b) which opens the jaws (i.e. parts 98 and 103) of the assembly and allows a sheet to come between them.