1. Field of the Invention
This invention relates to a small-sized ink jet color recording apparatus adapted to fly ink to a recording medium by an ink jet method to form a color image.
2. Description of the Related Art
As shown in FIG. 11, the conventional ink jet color recording apparatus 80 is so constructed that a recording head 82 (hereinafter simply referred to as head 82) is reciprocated along a guide 84 and with recording paper P transported in the direction U intersecting perpendicularly to the reciprocating direction W of the head, dye ink is flown according to the image information to form an image.
As shown in FIG. 12, the head 82 is provided with a storing part 86B for storing black ink, a storing part 86C for storing color ink, a nozzle 88B for discharging black ink, and a nozzle 88C for discharging color ink.
As the nozzles 88B, 88C have a small diameter, ink is dried to easily cause clogging. Therefore, frequently the ink is jammed not to be flown so that a desired image cannot be formed. As a countermeasure, generally, a maintenance part 89 (see FIGS. 11 and 12) having a suction system is provided, whereby when the image quality is lowered, ink in the nozzles 88B, 88C is sucked and removed to recover the injection function of the nozzles 88B, 88C.
The inventors have, as shown in FIG. 13, invented an ink jet color recording apparatus 90 adapted to suck ink by one small-sized suction pump 92 and filed an application for it. The contents of the invention are disclosed in Japanese Published Unexamined Patent Application No. Hei 10-067121.
The apparatus 90 is provided with a cap member 94B corresponding to the nozzle 88B and a cap member 94C corresponding to the nozzle 88C. Hoses 96B, 96C as an ink suction path are respectively connected to the bottoms of the cap members 94B and 94C, and the other ends of the hoses 96B, 96C are respectively connected to a first suction port 98 and a second suction port 99 of the suction pump 92.
The ink jet color recording apparatus 90 is so constructed that suction of the nozzle 88B and suction of the nozzle 88c are individually performed by the small-sized suction pump 92.
Recently, however, ink (pigment ink) mainly including pigment ingredients has been used to strengthen the water resisting property of ink. The pigment ink is more liable to dry than the dye ink used heretofore. Consequently, it has a disadvantage in that ink is solidified in the cap members 94B, 94C, so ink in the nozzles 88B, 88C is not sufficiently removed. Further, in sucking, ink adheres to the inner wall or the like of the hoses 96B, 96C to become solid ink residue 100, which results in the disadvantage that the function of the maintenance part 89 is not exhibited sufficiently.
The present invention has been made in view of the above circumstances and provides an ink jet color recording apparatus capable of forming a favorable image by preventing solidification.
According to an aspect of the present invention, the ink jet color recording apparatus has plural ink tanks for respectively storing ink different in composition; plural recording heads each having a nozzle for injecting ink in the ink tanks; and a cap member for recovering ink in the nozzle, wherein the ink jet color recording apparatus comprises: a recovery step of recovering the injection function of the nozzle by recovering ink in the nozzle into the cap member; and the supply step of supplying ink different in composition from the ink in the nozzle to the same cap member after the recovery step.
The ink in the nozzle is recovered into the cap member by the recovery step. Then, ink different in composition from the ink is supplied to the same cap member by the supply step to mix the ink in the cap member.
Thus, the ink recovered in the cap member is made into the mixed ink hard to dry so that the ink is hard to be solidified.
According to another aspect of the invention, the ink jet color recording apparatus is characterized in that ink of different compositions is pigment ink and dye ink.
The pigment ink which is easy to dry so that it is liable to be solidified is mixed with the dye ink in the cap member so that the density is lowered. Thus, the ink is made into mixed ink hard to dry, that is, hard to be solidified.
According to another aspect of the invention, the ink jet color recording apparatus is characterized in that the recovery step is the step of sucking ink from the nozzle.
This suction is frequently performed when an abnormal image is formed.
The injection function of the nozzle can be surely recovered.
In the ink jet color recording apparatus of the invention, however, when the recovery step is performed, sometimes ink adheres to the inner wall of the suction system used in suction and such adhering ink (hereinafter referred to as adhering ink) is easy to dry. Accordingly, after the supply step, the suction step of sucking ink staying in the cap member is performed, whereby the staying ink and the adhering ink are mixed so that the composition of the adhering ink is made into mixed ink hard to dry so as to sufficiently secure the sucking force of the suction system.
According to another aspect of the invention, the ink jet color recording apparatus is characterized in that the recovery step is the step of blank-injecting ink from the nozzle.
This blank injection is often performed periodically.
After the supply step performed after the recovery step, the suction step of sucking ink staying in the cap member may be performed. Thus, the mixed ink staying in the cap member can be immediately removed.
According to another aspect of the invention, the method for recovering ink-jet recording head having the following steps: vacuuming a pigment-base liquid ink form a nozzle into a cap member having a ink guide tube (hose);and supplying a dye-base liquid ink into the ink guide tube through the cap member.
According to another aspect of the invention, the ink-jet recording apparatus having a recording head having a nozzle for injecting an pigment-base ink; a cap member for recovering the ink in the nozzle; an ink guide tube (hose) connected to the cap member; and an ink supplying device that supply a dye-base ink into the ink guide tube through the cap member.
The ink supplying device may be a second recording head having the dye-base ink.