Abstract: An ink composition giving erasable white ink patterns and containing water and sodium benzoate dissolved in the water in an amount of at least 5 parts by weight per 100 parts by weight of the water. A writing instrument having a pen tip and an ink tank which contains the above ink composition and which is in fluid communication with the pen tip.

Abstract: An ink containing a coloring agent dissolved in a mixed solvent including a first solvent which is liquid at 20° C. and which is polyalkylene glycol or an ethylene glycol monoether and a second solvent selected from monohydric alcohols, ketones, esters and halogenated hydrocarbons. An image of the ink formed on an ink permeable sheet penetrates through the sheet and is transferred to a surface of a desired object overlaid with the sheet.

Abstract: A method of making a design on a receiving surface of an object, including overlaying a surface bearing an original pattern with a transparent or translucent thin sheet capable of permeating an ink, and tracing the original pattern on the sheet with an ink containing an organic solvent in which a first, white coloring agent selected from salicylic acid and acetylsalicylic acid and a second coloring agent giving a color other than white are dissolved, thereby to form a copy pattern on the surface of the sheet. The copy pattern-bearing sheet is overlaid with the receiving surface and the assembly is heated while maintaining the receiving surface in pressure contact with the sheet, whereby the ink of the copy pattern penetrates through the sheet onto the receiving surface to form thereon the design having a white color attributed to the first coloring agent or a color attributed to the second coloring agent, depending upon the heating time.

Abstract: A substantially colorless, transparent ink composition which affords erasable, white ink images includes an organic solvent, an organic substance which is dissolved in the organic solvent, which has a molecular weight of less than 1,000 and which is a white or colorless solid at room temperature, and a polymer which is dissolved in the organic solvent and which has a molecular weight of at least 10,000.

Abstract: The object of the present invention is to provide a pressure sensitive reproducing material which allows reproduced letters or patterns to fade away automatically with the passage of time.The present invention accomplished the object by a pressure sensitive reproducing material composed of a colored material supported on a substrate, in which the colored material comprises a phthalein group indicator which is color-developed by an inorganic weakly basic substance jointly used with an organic amine and contains hygroscopic material or drying inhibitor.

Abstract: The object of the present invention is to provide a new ink composition and a reproducing material without using any pigment, capable of drawing or reproducing clear white colored letters or patterns on a sheet of black or dark colored paper, cloth, leather or the like, and the letters or patterns drawn or reproduced are easily erasable with the application of water when they become unnecessary. The ink composition of the present invention comprises a white colored water soluble aliphatic sulfate as a coloring matter. The white colored water soluble aliphatic sulfate which can be used in the present invention includes, alkali-salt of lauryl sulfate, myristil sulfate, cetyl sulfate, stearil sulfate and the like, of which alkali-salt includes sodium, potassium, lithium and the like. As the liquid ink composition, a powder of the white colored water soluble aliphatic sulfate is dispersed in a monohydric alcohol.

Abstract: An aqueous transparent ink composition affording white ink patterns which are erasable with weakly acidic or ammoniacal liquid, and including an aqueous medium, and an ammine complex salt of zinc dissolved in the aqueous medium.

Abstract: An aqueous ink composition useful as a writing ink, including a water-insoluble coloring agent, and a water-soluble polymeric material having a molecular weight of at least about 1.times.10.sup.5. Preferably, the polymeric material is a polyethylene oxide or an alginic acid derivative. Ink images drawn on paper using the ink composition may be easily erased by rubbing with a rubber eraser.

Abstract: An ink composition containing an indicator of phthalein series colored by the conjoint use of an inorganic weakly basic substance and an organic amine. This ink composition shows a clear tint and possesses good stability so that it is free of fading on storage. Images produced with this ink composition can be erased by wiping them with a wet cloth, paper or other fibrous materials or by drying.

Abstract: An ink composition which comprises a solution of cobalt thiocyanate or a mixture of a compound capable of producing a thiocyanate ion and a compound capable of producing a cobalt ion in a liquid vehicle, the solution having been incorporated with polyalkylene glycol. This ink composition can give vivid inking images of deep blue color, which images can be erased, if necessary, by wiping with cloth, paper, fibrous material or the like impregnated with water.

Abstract: A coloring composition for line- or pattern-drawing elements which comprises as a base material thereof one or more acidic sublimating substances such as benzoic acid, salicylic acid and phthalic acid. Lines and/or patterns drawn with the coloring composition are easily erased by heating.