摘要:
A developing roller including a mandrel, an elastic layer provided on the mandrel and containing a cured material of an addition curable-type dimethyl silicone rubber, and a surface layer containing a urethane resin that covers the circumferential surface of the elastic layer. The urethane resin has a structure represented by the following formula (1), and one or both structures selected from a structure represented by the following formula (2) and a structure represented by the following formula (3) between two adjacent urethane linkages.
摘要:
A method of rolling raw materials inclusive of slabs for the manufacture of beam blanks, and a roll to be used therefor, are disclosed. This method includes the steps of (a) subjecting a raw material, whose section consists of a web portion and a flange portion(s) having a width wider than the thickness of the web portion, to such a partial rolling that the web portion is partially rolled at regions inclusive of at least the joints of the flange portion(s), except the remaining central region, among a plurality of regions divided in the widthwise direction of the web portion, and (b) subjecting only the remaining central regions to a rolling. In the practice of this method, there is used a roll consisting of a single cylindrical drum including a first segment and a second segment arranged side by side to each other; the first segment having at least one relief of circumferential grooves facing the web portion; a plurality of rolling collars separated apart from each other through the relief in the axial direction, and serving for the partial rolling of the web portion, and a circumferential groove(s) dividing a side of the rolling collar for the web portion near the joint and enclosing the flange portion; and the second segment having a pair of reliefs each composed of a wider circumferential groove facing the flange portion, and a rolling drum extending between the reliefs and serving for the rolling of only the remaining central region of the web portion.
摘要:
A method of forming a beam blank, wherein:said method comprises:a process in which a plate-shaped slab is reduction-rolled in the widthwise direction by means of working rolls having box calibers each formed at the center thereof with a belly, whereby side spreadings are generated at opposite end portions in the widthwise direction of said slab to provide a blank of being a dog-bone shape in cross-section; anda process in which said blank is rolled by means of working rolls having beam blank calibers to provide a beam blank being of a predetermined shape in cross section; said process, in which the plate-shaped slab is reduction-rolled in the widthwise direction by means of the working rolls having the box calibers each formed at the center thereof with the belly, preferably comprising: a first step in which said plate-shaped slab is reduction-rolled in the widthwise direction by means of box calibers each formed at the center thereof with a belly to provide grooves for positioning in the centers at opposite end faces in the widthwise direction of the plate-shaped slab; a second step in which said plate-shaped slab is further successively reduction-rolled in the widthwise direction by means of respective box calibers successively larger in caliber width than those used in the preceding step and each formed at the center thereof with a belly fit in said groove; and a third step in which said plate-shaped slab is further reduction-rolled in the widthwise direction by means of working rolls with flat bottoms or working rolls having box calibers each formed with a belly low in height, whereby recesses formed by use of said bellies at opposite end faces in the widthwise direction of the slab are lessened in depth and the side spreadings are further facilitated.
摘要:
A developing roller used for formation of an electrophotographic image with high quality is provided in which even in storage and use under a high temperature and high humidity environment, peel-off of a surface layer from an elastic layer is suppressed, and a toner hardly adheres to the surface of the developing roller.The developing roller is a developing roller including a mandrel, an elastic layer provided on the mandrel and containing a cured material of an addition curable-type dimethyl silicone rubber, and a surface layer containing a urethane resin that covers the circumferential surface of the elastic layer, wherein the urethane resin has a structure represented by the following formula (1), and one or both structures selected from a structure represented by the following formula (2) and a structure represented by the following formula (3) between two adjacent urethane linkages.
摘要:
There is provided a process for producing a regenerated elastic roller which can be again used for the formation of high-quality electrophotographic images by sufficiently relaxing a compression set of the elastic roller having the compression set caused in an elastic layer in usage. The process for producing a regenerated elastic roller includes a step of heating an elastic roller having a conductive mandrel and an elastic layer and having a compression set caused in the elastic layer, in a cylindrical mold to thermally expand the elastic layer and to cause a surface of the elastic roller to contact an inner wall of the cylindrical mold.