Abstract: A method of producing a glass blank with a high rate and high efficiency of deposition on a starting member is provided. A raw material powder including silica-glass-containing particles is transferred with a carrier gas and supplied into a flame, and the raw material powder and the flame are sprayed on a starting member to deposit the raw material powder on the starting member and form a porous body. The porous body is consolidated by heating.

Abstract: A dehydration and consolidation furnace and a dehydration and consolidation method in which gas in a chamber does not leak to a furnace body room and gas in a furnace body room does not leak into a chamber is provided. A furnace of one embodiment of this invention has first muffle tube 3 and second muffle tube 4. The second muffle tube 4 is arranged coaxially around the first muffle tube 3. An optical fiber preform is arranged in this furnace. During the dehydration and consolidation process the pressure of the intermediate room 10 is set lower than a pressure inside the first muffle tube and outside the second muffle tube, and a gas supply and exhaust of the intermediate room 10 are performed independent of the gas supply and exhaust of the first muffle tube and a furnace body room.

Abstract: A dehydration and consolidation furnace and a dehydration and consolidation method in which gas in a chamber does not leak to a furnace body room and gas in a furnace body room does not leak into a chamber is provided. A furnace of one embodiment of this invention has first muffle tube 3 and second muffle tube 4. The second muffle tube 4 is arranged coaxially around the first muffle tube 3. An optical fiber preform is arranged in this furnace. During the dehydration and consolidation process the pressure of the intermediate room 10 is set lower than a pressure inside the first muffle tube and outside the second muffle tube, and a gas supply and exhaust of the intermediate room 10 are performed independent of the gas supply and exhaust of the first muffle tube and a furnace body room.

Abstract: The object of the invention is to provide an apparatus for manufacturing a porous glass preform, which comprises a reaction vessel in which local stress concentration caused by expansion due to heat is prevented, and there is no fear of the occurrence of deformation or cracks. The apparatus of this invention manufactures the porous glass preform by depositing glass particles blown from a burner on the seed rod rotating around its axis, and this apparatus is characterized in that the reaction vessel is provided with a means for relieving concentration of stress due to thermal expansion of the reaction vessel.

Abstract: Lead-containing fluoride glass comprises 50-70 mol % of ZrF.sub.4, 3-5 mol % of LaF.sub.3, 0.1-3 mol % of YF.sub.3, and 2-15 mol % of NaF and/or LiF and/or CsF, where LaF.sub.3 +YF.sub.3 =4.5-6 mol %, and further comprises lead. An optical fiber comprises a core made of the lead-containing fluoride glass and a cladding surrounding the core. A process for producing an optical fiber comprises forming a base material for a core of the lead-containing fluoride glass, forming a base material for a cladding of fluoride glass containing 30-60 mol % of HfF.sub.4, and drawing the base materials into an optical fiber at a drawing temperature of 315-340 .degree. C.

Abstract: Ink is reserved in a cartridge case. On this cartridge case, there are fixed an ink jet head and an electric connecting member in a stacked state. The ink jet head is constructed to include: ink supply holes adapted to be supplied with the ink from the cartridge case; ink passages communicating with the ink supply holes; nozzles formed in the leading ends of the ink passages; and ink ejecting device such as piezoelectric elements disposed to correspond to the ink passages for ejecting the ink from the nozzles. These nozzles and the ink passages are substantially perpendicular. Moreover, the stacking direction, the ink supply direction from the cartridge case to the ink supply holes, and the ink ejecting direction from the nozzles are made substantially identical. The electric connecting member is made of a flexible frame or a metal lead frame. Thus, the ink jet head is assembled merely by stacking those individual components in the common direction.

Abstract: An ink jet head includes a nozzle plate having a nozzle through the nozzle plate in its thickness direction, a base plate laminated with the nozzle plate and having an ink supplying hole through the base plate in its thickness direction, a pressure chamber connected to the nozzle and the ink supplying hole in the substantially perpendicular manner and provided with a pressure means on the bonded surface of the nozzle plate and the base plate. The nozzle and the ink supplying hole are made narrower than the pressure chamber and the connecting channel. The plural nozzles, pressure chambers, connecting channels, and ink supplying holes are provided. A common ink chamber connecting to a plurality of the ink supplying holes are provided on the opposite surface to the nozzle plate laminated with the base plate in the perpendicular manner to the nozzle plate. A projection is formed in the nozzle plate and the nozzle is provided through the projection.

Abstract: Lead-containing fluoride glass comprises 50-70 mol % of ZrF.sub.4, 3-5 mol % of LaF.sub.3, 0.1-3 mol % of YF.sub.3, and 2-15 mol % of NaF and/or LiF and/or CsF, where LaF.sub.3 +YF.sub.3 =4.5-6 mol %, and further comprises lead. An optical fiber comprises a core made of the lead-containing fluoride glass and a cladding surrounding the core. A process for producing an optical fiber comprises forming a base material for a core of the lead-containing fluoride glass, forming a base material for a cladding of fluoride glass containing 30-60 mol % of HfF.sub.4, and drawing the base materials into an optical fiber at a drawing temperature of 315.degree.-340.degree. C.

Abstract: A dot printer includes: a platen and a printing head encased in a printer case in the vertical direction; a paper housing portion provided laterally of the platen; a feed roller disposed laterally of the printing head for feeding a paper taken out of a paper housing portion to the printing head; and a discharge roller disposed laterally of the printing head for discharging the paper outside of the case. With this construction, the printer can be made thin and can also be miniaturized.

Abstract: The invention relates to an optical fiber in which an optically functioning element is doped in at least the core, and the cladding is hermetically coated with carbon film and an optical fiber-type optically active device comprising: an optical fiber loop bundle constituted by a plurality of winds of an optical fiber hermetically coated with carbon and doped with an optionally functioning element; and beam introducing means for introducing a beam for pumping the optically functioning element into the optical fiber loop bundle.