Abstract: A paper feed unit has a paper feed tray stacking sheets thereon, a primary paper feed roller and a secondary paper feed member, wherein an uppermost sheet among the sheets stacked on the paper feed tray is transferred toward the secondary paper feed member from the primary paper feed roller, a tip end of the sheet then contacts with the secondary paper feed member, and primary paper feed is then completed while the sheet is being bent. A counter rotation stop mechanism, which allows the primary paper feed roller to rotate in a paper feed direction but prevents the primary paper feed roller from rotating in a counter direction to the paper feed direction, and a rotation stop release mechanism, which releases a state in which the primary paper feed roller is prevented from rotating in the counter direction by the counter rotation stop mechanism, are also provided.

Abstract: The present invention is a polishing compound comprising a colloidal solution containing 1˜15 wt. % of silicon oxide particles of 8˜500 nanometer average diameter, wherein said colloidal solution is prepared as a buffer solution which has buffering action between pH 8.7˜10.6 by the addition of one combination selected from groups composed by weak acid and strong base, strong acid and weak base or weak acid and weak base, and logarithms of reciprocal number of acid dissociation constant at 25° C. of said weak acid and/or weak base is 8.0˜12.0.

Abstract: The present invention provides a polishing compound which does not make stain grow on the surface of work-piece comprising, the dispersion containing 1-30 wt. % of metal oxide particles having 8-500 nm average diameter, acid or alkali and salt, and whose pH is 7-12. Desirably said polishing compound is the compound in which water soluble organic solvent is contained. Further, present invention provides edge polishing method and surface polishing method by use of said polishing compound.

Abstract: The present invention is a polishing compound comprising a colloidal solution of silicon oxide to which an alkaline component and an acid component are added in order to have a buffering action, wherein said alkali component is a quaternary ammonium whose carbon number per one molecular is smaller than 12, and said acid component is at least one selected from the group composed by carbonic acid, boric acid and silicic acid.

Abstract: A slurry recycling system of a CMP apparatus, and a method of the same, which restores the state of agglomeration of the abrasive grains to the initial state to enable reuse of the slurry and thereby reduces the cost of the polishing work and improves the operating rate of the CMP apparatus. Slurry S used in the CMP apparatus 1 is sent to a dispersion chamber 31. A vibration element 40 of an ultrasonic dispersion apparatus 4 mounted in the dispersion chamber 31 is made to vibrate by a vibrator 41 to generate ultrasonic vibration energy, whereby the agglomerated particles in the slurry S are made to disperse. Suitably thereafter, the slurry S is returned to the slurry feed apparatus 300 to enable reuse of the slurry S.

Abstract: A slurry recycling system for a CMP apparatus includes a flow path through which a slurry used in the CMP apparatus flows. A first filter is disposed in the flow path for filtering out foreign matter of a particle size of more than 0.5 microns mixed in said slurry. A second filter is preferably disposed in the flow path at a location upstream of and away from the first filter for filtering out foreign matter of a particle size of more than 10 microns mixed in said slurry. Preferably, provisions are made for a concentration adjuster for adjusting the concentration of abrasives in said slurry to substantially an initial value before use, and a pH adjuster for adjusting the pH of said slurry to substantially an initial pH value before use.

Abstract: The direction of an optical axis of an excitation optical system is so set that the same intersects with an optical axis of a photoreceiving optical system on a cornea and an excitation light beam is not incident upon a crystalline lens through a pupil. The photoreceiving optical system comprises a one-dimensional solid-state image pickup device as a photodetector, and a slit is arranged on a light incidence side of the one-dimensional solid-state image pickup device for distinguishing measuring light generated from the cornea from that generated from other eyeball portions and introducing the same into the one-dimensional solid-state image pickup device. Raman scattered light or fluorescence generated from the cornea can be detected by that of photoelectric conversion elements of the one-dimensional solid-state image pickup device positioned on the optical axis of the photoreceiving optical system, so that an intraocular substance is obtained on the basis of its detected value.

Abstract: Relative directions of excitation and photoreceiving optical systems are so set that an angle formed by optical axes thereof in the air is 14.degree., and an eyeball is fixed in such a direction that its ocular axis divides the angle formed by the optical axes into two equal parts. On a light incidence side of a one-dimensional solid-state image pickup device of the photoreceiving optical system, a slit is arranged for inputting measuring light components generated from portions of the eyeball having different depth positions on an excitation light beam in photoelectric conversion elements of different positions of the image pickup device.

Abstract: A coating composition for thick coating prepared by adding an aggregate to a coating liquid containing 5 to 40% by weight as SiO.sub.2 of a coloidal silica and 3 to 40% by weight of disolved and/or finely dispersed organic polymer, having an SiO.sub.2 /M.sub.2 O mole ratio (in which M is a monovalent alkali metal atom) of at least 7, and having a viscosity lower than 100 c.p. at 20.degree. C. when kept in the sealed state at 50.degree. C. for 10 days.Said coating composition being especially suitable for coating of 1-20 kg/m.sup.2 in thickness and storable for a long period of time with an excellent stability, giving a cured coating having high water resistance, good weather resistance, high adhesive strength and no efflorescence in its surface.

Abstract: A process for preparing a mold by preparing a slurry of refractory powder in a binder solution comprising silica sol and monomethyl triethanol ammonium silicate or tetraethanol ammonium silicate at a mole ratio of SiO.sub.2 /M.sub.2 O of 10 to 22 and a mole ratio of SiO.sub.2 /NR of 9 to 28 wherein M represents Li or Na and NR represents monoethyl triethanol ammonium hydroxide or tetraethanol ammonium hydroxide, and repeating an overcoating of said slurry and a refractory powder by coating said slurry on a pattern, sanding said refractory powder on the coated pattern and drying it to form a green mold, separating said green mold from said pattern and calcining said green mold.

Abstract: A coating composition for building materials which comprises 100 parts by weight of a quaternary ammonium silicate having a silica content, calculated as SiO.sub.2, of 5 to 70% by weight, 2 to 200 parts by weight of a metal oxide and/or hydroxide capable of converting silica sol to silica gel and water in an amount sufficient to plasticize said composition.

Abstract: Calcium silicate monohydrate (2CaO.sup.. SiO.sub.2.sup.. H.sub.2 O) can be produced in a coating which has been formed by a coating material containing silica sol alone or silica sol and other additives such as aggregate, viscosity increasing agent, etc. by subjecting the coating to a chemical treatment such as heat-treatment, ultra-violet ray irradiation treatment, etc. in the presence of water and a calcium compound which may be present either in the coating material, or in the treating liquid, or in an object to be coated. The film which contains the calcium silicate monohydrate produced by said chemical treatment has remarkably high hardness and is excellent in water-resistance, water-imperviousness, weather-resistance, and heat-resistance.

Abstract: The surface of an inorganic substrate comprising cement, concrete, gypsum or mixtures thereof is treated with a silicate solution or a silica sol comprising a monovalent alkali metal containing component, an ammonium containing component and a silica containing component at a molar ratio of 1:1.about. 10:4.about.5000 corresponding to M.sub.2 O:[R.sub.1 R.sub.2 R.sub.3 R.sub.4 N].sub.2 O: SiO.sub.2 wherein M is Li, K or Na; and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represent a hydrocarbon group or an alkanol group. The underlying inorganic substrate thus has a modified surface layer thereon having a thickness of less than 50 mm, which functions to protect and prevent deterioration of the underlying surface of said inorganic substrate.

Abstract: A coating composition for thick coating prepared by adding an aggregate to a coating liquid containing 5 to 40% by weight as SiO.sub.2 of a coloidal silica and 3 to 40% by weight of dissolved and/or finely dispersed organic polymer, having an SiO.sub. 2 /M.sub.2 O mole ratio (in which M is a monovalent alkali metal atom) of at least 7, and having a viscosity lower than 100 c.p. at 20.degree. C when kept in the sealed state at 50.degree. C for 10 days.Said coating composition being especially suitable for coating of 1 - 20 kg/m.sup.2 in thickness and storable for a long period of time with an excellent stability, giving a cured coating having high water resistance, good weather resistance, high adhesive strength and no efflorescence in its surface.

Abstract: A refractory composition comprises a basic refractory raw material such as oxides or hydroxides of magnesium, calcium, chromium or maganese, quaternary ammonium hydroxide and silica sol and/or silicate. The composition is used to prepare unfired refractories having a high compression strength by merely molding and drying it without the necessity of firing. When fired, it manifests comparable compression strength. The composition can also be used as monolithic refractory, refractory mortar, refractory coating agent, mold release, etc.