Abstract: An apparatus for ink-jet recording includes: (a) ink tanks installed removably in the apparatus, and configured to store ink; (b) a reservoir tank configured to temporarily store waste ink generated by a printing head for jetting ink supplied from the ink tanks onto the printing paper; (c) waste ink tanks formed in one piece with the ink tanks, and configured to store waste ink; (d) a discharging unit configured to discharge waste ink from the reservoir tank into the waste ink tanks; and (e) a control unit configured to discriminate whether or not the waste ink tanks are empty, and to control the discharging unit to discharge waste ink of a predetermined quantity stored in the reservoir tank into the empty waste ink tank.

Abstract: An apparatus for ink-jet recording includes: (a) ink tanks installed removably in the apparatus, and configured to store ink; (b) a reservoir tank configured to temporarily store waste ink generated by a printing head for jetting ink supplied from the ink tanks onto the printing paper; (c) waste ink tanks formed in one piece with the ink tanks, and configured to store waste ink; (d) a discharging unit configured to discharge waste ink from the reservoir tank into the waste ink tanks; and (e) a control unit configured to discriminate whether or not the waste ink tanks are empty, and to control the discharging unit to discharge waste ink of a predetermined quantity stored in the reservoir tank into the empty waste ink tank.

Abstract: A printing sheet which prevents setoff while transferring a sufficient quantity of ink and maintains necessary dot uniformity can be obtained by ensuring characteristics that the centerline average roughness showing the larger value is 1.0-3.5 &mgr;m and the ratio of centerline average obtained by dividing the larger value by the smaller value is less than 1.15 where said values are chosen at the point where the difference between the centerline average roughness in a certain direction and the centerline average roughness at right angles to said direction is maximal. Further, the abovementioned quality is further improved by appropriately ensuring that the oil absorbability is more than 4 mg/cm2 and less than 7 mg/cm2 when the contact time between the oil component having a surface tension of 27-30 mN/m at 20° C. and the printing sheet is 5 seconds and/or that the median pore diameter is 1.7-3.5 &mgr;m, in addition to the abovementioned characteristics.

Abstract: A printing sheet which prevents setoff while transferring a sufficient quantity of ink and maintains necessary dot uniformity can be obtained by ensuring characteristics that the centerline average roughness showing the larger value is 1.0-3.5 &mgr;m and the ratio of centerline average obtained by dividing the larger value by the smaller value is less than 1.15 where said values are chosen at the point where the difference between the centerline average roughness in a certain direction and the centerline average roughness at right angles to said direction is maximal. Further, the abovementioned quality is further improved by appropriately ensuring that the oil absorbability is more than 4 mg/cm2 and less than 7 mg/cm2 when the contact time between the oil component having a surface tension of 27-30 mN/m at 20° C. and the printing sheet is 5 seconds and/or that the median pore diameter is 1.7-3.5 &mgr;m, in addition to the abovementioned characteristics.

Abstract: The disclosed stencil printing method can produce prints having high glossiness by inhibiting the uneven transfer of ink caused by operation of separation of stencil. A stencil printing apparatus is disclosed. The stencil printing method includes superposing one upon another a master stencil sheet (3) and a printing material (1) (a material to be printed) and pressing an ink supply element (2) to the master stencil sheet from the side opposite to the printing material, in the direction toward the printing material, thereby passing a printing ink through the master stencil sheet to transfer the ink to the printing material, wherein ink-passing porous member (4) is disposed between the ink supply element and the printing material to transfer the printing ink to the printing material through the porous member. The ink supply element is separated from the porous member while the porous member is left on the printing material, and then the porous member is separated from the printing material.

Abstract: A method for cleaning a thermal printing head, particularly in use for perforating stencil sheets, is provided, which does not require a special stencil sheet nor damage the thermal printing head, but makes it possible to remove deposits as required. The method is a method for cleaning a thermal printing head having a plurality of heating elements arranged transversely to a direction in which an article to be recorded is conveyed, which comprises heating and softening deposits appearing in the vicinity of said heating elements, and conveying a sheet in the above direction while said sheet is kept in contact with said heating elements so that said softened deposits are moved downwardly in the above direction. Said sheet may be a stencil sheet, and preferably the heating elements are all turned on to heat and soften deposits, so as to make perforations for solid printing in said stencil sheet.

Abstract: A W/O emulsion ink, which is superior in emulsion stability, causes no softening or separation even after stored for a long time, and can always provide prints of uniform quality, is provided. The emulsion ink has an oil phase and a water phase, in which said water phase has a pH of 6.0 to 12.0, preferably 7.0 to 9.0 at 23.degree. C. The emulsion ink may contain a water-insoluble colorant in the water phase and/or the oil phase. Preferably, the water phase has a pH buffer action.