Abstract: The present invention relates to an ink-jet printing method using an apparatus including a printing means for ejecting a black ink to a printing substrate to print characters or images on the printing substrate, and a drying means disposed on a downstream side of a transportation direction of the printing substrate, in which the printing substrate is a label printing substrate; the black ink is a water-based composite black ink; the water-based composite black ink contains a composite black pigment containing carbon black, and a content of the carbon black in the composite black pigment is not more than 25% by mass; and the drying means is an infrared heater for heating the water-based composite black ink ejected onto the printing substrate to a temperature of not lower than 95° C. and not higher than 125° C.

Abstract: The present invention relates to an ink-jet printing method using an apparatus including a printing means for ejecting a black ink to a printing substrate to print characters or images on the printing substrate, and a drying means disposed on a downstream side of a transportation direction of the printing substrate, in which the printing substrate is a label printing substrate; the black ink is a water-based composite black ink; the water-based composite black ink contains a composite black pigment containing carbon black, and a content of the carbon black in the composite black pigment is not more than 25% by mass; and the drying means is an infrared heater for heating the water-based composite black ink ejected onto the printing substrate to a temperature of not lower than 95° C. and not higher than 125° C.

Abstract: A wet-type plate-making machine is disclosed in which the amount of a developer in a developing tank and the toner concentration of the developer are maintained constant. In accordance with the detection values of two liquid level detection switches mounted in the developing tank, the developer is supplied from a developer refill pump thereby to maintain a constant amount of developer. The toner concentration of the developer is maintained constant by supplying the toner from a toner refill pump when the detection value of a concentration detection unit of light-transmission type is low, and by supplying the developer from a developer refill pump when the detection value of the concentration detection unit is high. In the case where the developer concentration or the toner concentration fails to change in this control operation, an alarm signal is outputted indicating that the developer bottle or the toner bottle, as the case may be, is empty.