Abstract: According to a first aspect of this invention, it is assumed that the recording is carried out on the recording medium by a non-catalyst-containing recording agent and a liquid-state catalyst is coated on the recording medium at the time of erasing processing and subsequently the heating and irradiation of near infrared rays are carried out as the erasing processing. Also, according to a second aspect of this invention, it is assumed that the recording is carried out on the recording medium by a catalyst-containing recording agent and, at the erasing processing time, the heating and irradiation of the recording agent are simultaneously carried out using a thermal emission and near IR irradiation source such as a halogen lamp.

Abstract: A water-based pigment-type ink containing at least water, a pigment and a dispersant, the pigment particles having an average particle diameter of not larger than 0.1 .mu.m, the weight ratio of the pigment to the dispersant being from 1.2 to 5. The water-based pigment-type ink exhibits more excellent color tone and chroma, by adding the fluorescent pigment in an amount of from 0.1% by weight to 3% by weight with respect to the amount of the ink. Furthermore, the water-based pigment-type ink comprises at least a pigment, a high-molecular dispersant, a surfactant and water, the pigment particles having an average particle diameter of not larger than 80 nm, a maximum particle diameter not being larger than 0.1 .mu.m, the high-molecular dispersant being added in an amount of from 3% by weight to 20% by weight with respect to the amount of the ink, and the surfactant being added in an amount of from 2% by weight to 4% by weight with respect to the amount of the ink.

Abstract: An ink ribbon cassette is pivotably mounted to a printer. Ink ribbon is accommodated in the ink ribbon cassette and is caused to travel by a ribbon feed roller driven by a drive shaft provided in the printer. Printing operation is carried out at the cassette end arm portion by a printing head, while the cassette end arm portion is reciprocatingly moved in the widthwise direction of the ink ribbon relative to the fixed printing head by an actuating mechanism so that a printing region of the ink ribbon is diffused and becomes wider than a printing width of the printing head. The actuating mechanism includes a small gear integral with the ribbon feed roller, a cam driven by the small gear, and a lever engaging with the cam.

Abstract: One of a ribbon feed roller (32) and a pressure roller (34) for making an endless ink ribbon (30) run is displaceable relative to the other roller thereof for facilitation of replacement of the ink ribbon, and can be locked at a withdrawn position thereof. In a state where one roller is locked at the withdrawn position, mounting of the ink ribbon cassette on a printer is obstructed. Also, a running direction and an orientation of the endless ink ribbon are defined so that damage to the bonded portion of the endless ink ribbon is delayed as much as possible.

Abstract: An inked ribbon cassette comprising an ink supply felt, a first gear arranged in contact with the felt and a second gear in engagement with the first gear. An ink ribbon is pinched between the first and the second gears and driven by the first and the second gears upon rotation thereof. Accordingly, ink is transferred from the felt to the first gear, and in turn, from the first gear to the ink ribbon. There are grooves in the first gear for containing ink therein ink is excessively transferred from the ink supply felt to the first gear. The grooves are preferably provided in bottom lands of the first gear by increasing the whole depth of the first gear.