1. Field of the Invention
The present invention relates to a recording head cleaning apparatus, an image recording apparatus and a recording head cleaning method, and more particularly to a recording head maintenance system in an image recording apparatus which employs a drum conveyance system to convey a recording medium.
2. Description of the Related Art
As a general image recording apparatus, it is suitable to use an inkjet recording apparatus, which forms a desired image on a recording medium by ejecting and depositing colored inks from a plurality of nozzles provided in an inkjet head. If the inkjet head is operated for a long period of time, adhering matter such as solidified ink or paper dust from the recording medium, and the like, adhere to the nozzle surface. In particular, if adhering matter becomes attached to the vicinity of the nozzles and the nozzle apertures, this gives rise to deflection of the ejection direction of the ink ejected from the nozzles, or reduction in the ejection volume, and so on, and therefore an inkjet recording apparatus is composed in such a manner that cleaning of the nozzle surface is carried out appropriately.
Japanese Patent Application Publication No. 2000-094703 discloses a cleaning apparatus which applies a cleaning liquid in a non-contact fashion to an inkjet head which is horizontally installed, by rotating an application roller having a cylindrical shape which is immersed in the cleaning liquid. However, the nozzle surface of an inkjet head that records an image on a recording sheet held on the outer circumferential surface of a cylindrical conveyance roller has a prescribed inclination with respect to the horizontal, in order to maintain a uniform distance with respect to the recording sheet. When carrying out cleaning of the inkjet head thus disposed in the inclined state, using an application roller having cleaning liquid held on the surface thereof, it is necessary to incline the application roller in such a manner that the application roller is parallel to the nozzle surface.
If an application roller 200 in a cleaning apparatus 202 shown in FIG. 8 is inclined in accordance with the inclination of a nozzle surface 204A of an inkjet head 204, then the state depicted in FIG. 9 is obtained. In the cleaning apparatus 202 depicted in FIG. 9, a liquid surface 212 of a cleaning liquid 210 accommodated in a case 208 is inclined with respect to a rotational axle 216 of the cleaning roller 200, and therefore it is almost impossible to create a coating layer (liquid pool) 214 of the cleaning liquid in an upper portion 200B of an inclined surface 200A of the application roller 200, and hence the coating layer 214 of the cleaning liquid assumes a non-uniform shape and collects in a lower portion 200C of the inclined surface 200A. In the coating layer 214 having an instable shape of this kind, it is difficult to achieve stable application of the cleaning liquid to the nozzle surface 204A of the inkjet head 204.