An ink-jet printer has a frame, a carriage, a waste ink collecting box and waste ink spreading device. The paper feeder is mounted to one side of the frame, while a discharge device is mounted to the other side of the frame. The carriage is provided with at least one ink cartridge and is transversely reciprocated between a printing area and a service area along a guide rod that is horizontally mounted to the frame. The waste ink collecting box is for collecting waste ink discharged from the ink cartridge in the service area. The waste ink spreading device uniformly spreads the waste ink heaped in the waste ink collecting box. The waste ink spreading device may have a waste ink spreader. The waste ink spreader may have a hinge portion rotatably mounted to the waste ink collecting box, a spreader arm extended from one side of the hinge portion, the spreader arm spreading heaped waste ink uniformly in the waste ink collecting box, and a spreader head extended from the opposite end of the hinge portion, the spreader head being actuated for rotation of the spreader arm.

An ink set for jet-printing is disclosed. The ink set comprises an ink liquid containing a colorant and a substantially colorless liquid composition containing an anionic metal oxide colloid, which are to be mixed with the ink liquid after jetted, wherein a viscosity A cp of the ink liquid, a viscosity B cp of the liquid composition and a viscosity C cp of a mixture of equal amount of the ink liquid and the liquid composition satisfy the following relations; .vertline.A-B.vertline..ltoreq.5, 1<A<10, 1<B<10, and C/A>5.

When different liquids are charged in a plurality of nozzles, the liquids are drawn by suction or pushed out reliably from the nozzles, so that the liquids collected by suction or pushing out can be reused. For this purpose, a removing unit, which has a cap that operates to cover nozzle discharge ports and to come into tight contact with a head, is provided. Suction is performed from each nozzle separately. Different collection tubes and collection tanks are provided for the removing unit. A liquid having the same liquid composition is accumulated in one collection tank for the same liquid composition via the collection tube of a liquid channel for the same liquid composition.

Upon performing printing using a dye ink and a pigment ink and in addition a treatment liquid making those inks insoluble, two kinds of inks consisted of the pigment ink and the dye ink are used. After applying the pigment ink on a printing medium, the dye ink is applied overlaying with the pigment ink. After mixing these inks on the printing medium, the treatment liquid which makes the inks insoluble, is applied. In the alternative, a mixed ink in which a pigment ink not requiring a dispersant and the dye, is used. After application of this mixed ink on the printing medium, the treatment liquid which makes the ink insoluble, is applied. Therefore, problem of "crack", "soaking out", "overflow" or lowering of OD value which can be caused upon reaction of the pigment ink and the dye ink or the mixed ink with the treatment liquid, can be solved to achieve high quality printing.

Upon performing printing using a dye ink and a pigment ink and in addition a treatment liquid making those inks insoluble, two kinds of inks consisted of the pigment ink and the dye ink are used. After applying the pigment ink on a printing medium, the dye ink is applied overlaying with the pigment ink. After mixing these inks on the printing medium, the treatment liquid which makes the inks insoluble, is applied. In the alternative, a mixed ink in which a pigment ink not requiring a dispersant and the dye, is used. After application of this mixed ink on the printing medium, the treatment liquid which makes the ink insoluble, is applied. Therefore, problem of "crack", "soaking out", "overflow" or lowering of OD value which can be caused upon reaction of the pigment ink and the dye ink or the mixed ink with the treatment liquid, can be solved to achieve high quality printing.