Abstract: A double sheet detector includes a pair of rollers forming a nip through which a fed sheet passes, causing the rollers to separate. The amount of separation is transmitted to a transducer which generates a signal proportional to the sheet thickness. Signals from the transducer are frequently sensed and averaged over one or more full revolutions of the rollers, so that signal variations resulting from irregularities in the shape of the rollers are canceled out.

Abstract: A double sheet detector includes a pair of rollers forming a nip through which a fed sheet passes, causing the rollers to separate. The amount of separation is transmitted to a transducer which generates a signal proportional to the sheet thickness. Signals from the transducer are frequently sensed and averaged over one or more full revolutions of the rollers, so that signal variations resulting from irregularities in the shape of the rollers are canceled out.

Abstract: A feeder head includes suction belts to sequentially feed top sheets from a stack of sheets (e.g., paper). Before the belts receive suction and drive power, a suction cup raises the top sheet at a location between the belts to produce a corrugated shape in the top sheet which induce separation of a second sheet that might be adhered to the top sheet. A double sheet detector includes a pair of rollers forming a nip through which a fed sheet passes, causing the rollers to separate. The amount of separation is transmitted to a transducer which generates a signal proportional to the sheet thickness. Signals from the transducer are frequently sensed and averaged, so that signal variations resulting from irregularities in the shape of the rollers are canceled out.

Abstract: The identical printing of a stack of sheets (e.g., paper) is performed by vertically stacked inkjet printing units, each of which prints sheets at a printing speed. All sheets are fed from a stack along an infeed path at a feeding speed which is faster than the printing speed. The sheets are sequentially introduced into the respective printing heads, e.g., by the actuation of a gate mechanism disposed in the infeed path. After the sheets have been printed in the printing units at the slower printing speed, and after the print medium has been fixed, the sheets are discharged from the printing units and fed along a common outfeed path at the higher feeding speed. For variable-data printing, raster image processing is performed by assigned separate RIP computer units to process respective batches of the pages of the printing job.

Abstract: A feeder head includes suction belts to sequentially feed top sheets from a stack of sheets (e.g., paper). Before the belts receive suction and drive power, a suction cup raises the top sheet at a location between the belts to produce a corrugated shape in the top sheet which induce separation of a second sheet that might be adhered to the top sheet. A double sheet detector includes a pair of rollers forming a nip through which a fed sheet passes, causing the rollers to separate. The amount of separation is transmitted to a transducer which generates a signal proportional to the sheet thickness. Signals from the transducer are frequently sensed and averaged, so that signal variations resulting from irregularities in the shape of the rollers are canceled out.

Abstract: A sheet calendering method and apparatus including a calendering cylinder, a delivering cylinder, and a conveyor for transporting sheets between the calendering cylinder and the delivering cylinder; wherein the conveyor includes two flexible elongated members forming parallel endless loops around the calendering and delivering cylinders, a plurality of support members attached between the parallel loops, and a plurality of calendering plates each linked to an adjacent plate by the support members to form an endless belt.

Abstract: A sheet calendering method and apparatus including a calendering cylinder, a delivering cylinder, and a conveyor for transporting sheets between the calendering cylinder and the delivering cylinder; wherein the conveyor includes two flexible elongated members forming parallel endless loops around the calendering and delivering cylinders, a plurality of support members attached between the parallel loops, and a plurality of calendering plates each linked to an adjacent plate by the support members to form an endless belt.

Abstract: A convertible coating apparatus provides one or two side coating of a web having wet ink thereon to permit both printing and coating to be carried out prior to any drying operation. The apparatus includes a coating applicator roller in contact with a relatively hard back-up roller. The coating applicator roller is supplied with coating in both the one and two side operations while the back-up roller is supplied with coating only in the two side operation. Water is supplied to the back-up roller in the one side operation and the back-up roller has a hydrophilic surface which, when supplied with water, repels the wet ink on the web passing through the couple and prevents smudging and offset of the ink to the back-up roller. A method of carrying out the one and two side coating is also disclosed. A turning roller is also provided which guides the freshly inked web between inking operations without smudging the ink on the web.

Abstract: A convertible coating apparatus provides one or two side coating of a web having wet ink thereon to permit both printing and coating to be carried out prior to any drying operation. The apparatus includes a coating applicator roller in contact with a relatively hard back-up roller. The coating applicator roller is supplied with coating in both the one and two side operations while the back-up roller is supplied with coating only in the two side operation. Water is supplied to the back-up roller in the one side operation and the back-up roller has a hydrophilic surface which, when supplied with water, repels the wet ink on the web passing through the couple and prevents smudging and offset of the ink to the back-up roller. A method of carrying out the one and two side coating is also disclosed. A turning roller is also provided which guides the freshly inked web between inking operations without smudging the ink on the web.