Abstract: A cover is woven into a cylindrical shape with many warp yarns composed of a hydrophilic fiber and with one or several weft yarns composed of a hydrophilic fiber with a water shrinkage about 10 to 40%. This cover has a quality of rapid response for controlling the moisturizing condition of the printing surface which is designated by the difference in the weight of the cloth of the cover between a wetted condition in which the cover absorbs and stores enough water without dropping and a dry condition in which the cover is treated with a centrifugal dehydrator for 10 minutes after being wetted. The warp and weft yarns are of less than 220 denier and have a density of 20 threads per centimeter. The weight of the cloth of the cover is less than 200 g/m.sup.2 and the thickness is less than 0.5 mm.

Abstract: A sheet surface cleaing apparatus for cleaning the surface of a sheet on which painting or printing is to be conducted. The apparatus has a rotatable dust removing roll having a sticky surface capable of making rolling contact with the sheet surface to be cleaned. The apparatus also has a roll cleaning device mounted for movement parallel with the axis of rotation of the dust removing roll and capable of cleaning the surface of the dust removing roll. The dust removing roll is mounted for swinging movement between a position where it engages the roll cleaning device and a position where it engages the sheet surface. The surface of the roll cleaning device contactable with the dust removing roll is formed of a flexible porous cleaning pad which is mounted so as to be delivered in a direction perpendicular to the axis of rotation of the dust removing roll.

Abstract: A covering for a damping form roller prepared by knitting fabric into a cylindrical form consists of a pile yarn, a ground yarn and an elastic annex yarn. This elastic yarn knitted to straightly extend in a direction of a course, and to be caught and bound by base knit loop.The shrinking of a covering fabric of the invention which is inserted on the roller is more larger in the direction of circumference than in the direction of axis, and this shrinking in the direction of circumference sticks the inner surface of a covering fabric fast to the outer surface of roller, the shrinking in the direction of axis is very small. Thus the covering fabric sticks so fast to a roller without inequality that it is not necessary to bind both side ends of a covering fabric on the shaft of roller in mounting it on a roller, and can be supply water to the plate cylinder in a smooth and uniform manner, aiding in producing fine and beautiful prints continuously for a long period of time.