Abstract: Disclosed herein is a photosensitive solder resist ink capable of development with a dilute alkaline solution. It has a wide pre-curing latitude. It permits the pre-cured board to be stored for a long period of time. It is superior in resolution, sensitivity, and solder resistance. Disclosed also herein is a printed circuit board having good adhesion, chemical resistance, electrical properties, gold plating resistance, solder heat resistance, and electrocorrosion resistance. Disclosed also herein is a process for producing said printed circuit board by using said solder resist ink.The photosensitive solder resist ink comprises (A) an ultraviolet-curable resin containing 0-20 wt % of aromatic ring moiety which is obtained by reacting a polymer composed of (a) 40-100 mol % of ethylenically unsaturated monomer having an epoxy group and (b) 0-60 mol % of ethylenically unsaturated monomer capable of copolymerization therewith, with (meth)acrylic acid in an amount of 0.7-1.

Abstract: A resist ink composition developable with a diluted, alkaline solution, which exhibits high dispersion stability itself, can form a pattern with excellent resolution, even in the case of a low exposure amount, and can produce a cured resist film excellent in solvent resistance for high-performance printed circuits and which comprises an ultraviolet-curable resin obtained by copolymerizing (a) from 5 to 50% by weight of an ethylenically unsaturated monomer of a general formula: ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group; R.sub.2 represents a hydrogen atom or an alkyl group; n represent an integer of from 1 to 4, and/or glycerol mono(meth)acrylate, (b) from 10 to 90% by weight or glycidyl (meth)acrylate and (c) from 0 to 80% by weight of other ethylenically unsaturated monomers capable of copolymerizing with these (a) and (b), followed by reacting the resulting copolymer with from 0.7 to 1.

Abstract: Each of first and second contact blocks includes a substantially rectangular insulating member, a pair of stationary contact members projecting inward from the insulating member and supported with a predetermined interval therebetween, a movable contact member arranged between the pair of stationary contact members and supported by the insulating member, and first, second, and third terminals for electrically extracting the pair of stationary contact members and the movable contact member, respectively, and projecting from a base portion of the insulating member with predetermined intervals therebetween. An electromagnet includes a movable member for commonly acting on the movable contact members of the first and second contact blocks to move each movable contact member toward one of the pair of stationary contact members of each of the first and second contact blocks.

Abstract: A dial device houses switches which have functions related to the dial device. An opening is formed at the front end of the dial knob. Switch operating parts for these switches housed in the dial device are exposed through the opening. The switches are attached to a member such as the shaft by which the dial knob is supported, and these switches and their operating parts are left not turned even when the dial knob is turned.

Abstract: An aqueous acrylamide polymer solution is stabilized by causing it to contain in combination a 2-mercaptobenzimidazole compound and a phenolic antioxidant compound.