1. Technical Field
The present invention relates to a liquid ejection apparatus such as an inkjet printer, a capping device used in a liquid ejection apparatus, and an installation device for installing a liquid absorber in a cap.
2. Related Art
Typically, an inkjet printer (hereinafter, referred to as printer), which is a type of liquid ejection apparatus, performs printing by ejecting ink (liquid) onto a recording medium from a recording head (liquid ejection head) mounted on a carriage. The recording head has a great number of nozzles for ejection ink, and a piezoelectric element is provided in each of the nozzles. By activating some of the piezoelectric elements, specific ones of the nozzles are filled with ink, and the ink is ejected through the openings of the nozzles. The solvent of the ink in the nozzles is likely to evaporate from the nozzle openings. This increases the viscosity of the ink and can thus clog the nozzles. Also, atmospheric air can enter the interior of the nozzles through the openings, which causes air bubbles to stay in the ink. This results in printing problems such as missing dots.
To avoid such problems, printers as described above are equipped with a cleaning mechanism for a recording head. Such a cleaning mechanism includes a cap for sealing a nozzle-forming surface of the recording head and a suction pump for sucking air out of the cap. In this type of printer, flushing and cleaning are executed as necessary. Flushing refers to ejection of ink from the nozzles through excitement of the piezoelectric elements in response to a control signal unrelated to printing. Cleaning refers to suction of ink from the nozzles using vacuum, which is produced when the nozzle-forming surface is sealed with the cap and the suction pump is activated.
The cleaning mechanism is also capable of preventing the interior of the nozzles from drying by sealing the recording head with the cap when the printer is not performing printing. The cap has a box-like shape, and accommodates ink absorber (liquid absorber) for receiving and absorbing ink discharged from the nozzles during cleaning. Therefore, when the cap seals the recording head, ink solvent evaporated from the ink absorber maintains the moisture in the space surrounded by the cap and the recording head. This prevents the interior of the nozzles from drying.
JP-A-2000-62202 discloses a printer equipped with a capping member (cap) accommodating an ink absorber. The capping member of the printer disclosed in the publication is accommodated in a cap holder, and the ink absorber is accommodated in the capping member. Five pin portions are provided on the bottom in the cap holder. The pin portions are received by insertion holes formed in the capping member and through holes formed in the ink absorber. The distal end (upper end) of each pin portion protrudes upward from the upper surface of the ink absorber. A push plate is heat crimped to the distal ends of the pin portions, so that the push plate and the ink absorber are fixed in the capping member. The ink absorber is thus prevented from being raised off the interior of the cap.
The printer disclosed in JP-A-2000-62202 has a push plate above an ink absorber to prevent the ink absorber from being raised. Therefore, when the nozzle-forming surface of the recording head is sealed with the cap member, the push plate constitutes an impediment and increases the space between the upper surface of the ink absorber and the nozzle-forming surface. That is, even if the recording head is sealed with the cap when the printer is not performing printing, the size of the space defined by the cap and the recording head cannot be reduced. It is therefore impossible to increase the moisture retention of the space. As a result, the interior of the nozzles cannot be prevented from drying.
Also, in the case of JP-A-2000-62202, a push plate needs to be heat crimped to the distal ends of the pin portions, so that the ink absorber is fixed in the capping member. This complicates the installation of the ink absorber. Particularly, if a thin and small ink absorber is used, it tends to be deformed when being installed in the capping member. This further complicates the installation and hinders a heat crimping device from being inserted into the capping member.