Abstract: An ink composition is provided which can realize printing with excellent fixation even on a coated paper having a smooth surface. Further, an ink composition is also provided which, when used in ink jet printing, causes neither clogging nor creation of a precipitate. A copolymer of butyl acrylate, methyl methacrylate, and acrylic acid is added to an ink composition.

Abstract: The raceway groove width (W) of the inner ring 2 and the length (L) of the tapered roller 3 are finished within predetermined dimensional tolerances. The retaining rib face 2b of the inner ring 2 is machined such that it is a surface parallel to the small end faces 3b of the tapered rollers 3. The clearances .delta. which are defined when the tapered rollers 3 are disposed on the raceway surface 2a of the inner ring 2 and are contacted at the large end faces 3a thereof with the cone back face rib face 2c is secured to be within the dimensional range, .delta..ltoreq.0.4 mm.

Abstract: An agglomerated pigment comprises (1) an organic pigment compound, (2) either a sulfonated organic pigment compound obtained by incorporating at least one sulfonic group into the organic pigment compound or a sulfonated organic pigment derivative obtained by incorporating at least one sulfonic group into a derivative of the organic pigment compound, (3) univalent inorganic counter ions bonded to sulfonic groups of component (2), and (4) bivalent or higher inorganic counter ions which are bonded to sulfonic groups of component (2) and wherein each such group has an at least univalent positive charge, the surface of the agglomerated organic pigment as a whole being positively charged. An aqueous pigment dispersion and a water-based ink composition both having excellent storage stability, an agglomerated pigment for use as a raw material for the dispersion, and a process for producing the pigment are provided.

Abstract: A self-propelled vehicle capable of all directional movement over a floor surface and adapted to be guided along a path such as a semiconductor processing line. The vehicle is provided with at least three wheels having a construction enabling rotational movement in a rotational plane of the wheel and in a direction orthogonal thereto. When at least four wheels are provided, the vehicle is provided with a suspension mechanism for mounting the wheels and a mechanism for maintaining a parallel relationship of the suspension mechanism and a chassis of the vehicle so that slanting of the vehicle body during travel is avoided. Also, the vehicle is provided with a vibration preventing base interposed between the vehicle and a substance mounting base for controlling the proper vibration frequency of the vibration presenting base to be lower than 1/.sqroot.2 of the proper vibration frequency of the vehicle.