1. Technical Field
The present invention relates to a liquid drop ejecting device and liquid drop ejecting method which eject liquid drops (droplets) onto a recording medium by a head having liquid drop ejectors which eject liquid drops, and to a controller which controls the liquid drop ejecting device, and to a storage medium which stores a program.
2. Related Art
Inkjet printers, which have a head at which a plurality of liquid drop ejectors ejecting liquid drops are lined-up and which carry out image recording by ejecting ink drops from the liquid drop ejectors, are coming into wide use. Further, in recent years, inkjet printers have employed a two-liquid reacting system for the purposes of improving image density, improving on blurring (feathering) of ink into the sheet, shortening the drying time, and the like. This two-liquid reacting system applies onto a sheet, in addition to the inks of the respective colors, a reaction liquid (also called processing liquid) which makes components of the inks cohere, thicken, or become insoluble.
However, because the spreading of the ink liquid drop in the lateral direction lessens due to the ejection of the reaction liquid, it is easy for stripe-like image defects to become conspicuous due to non-ejection or directional bending of liquid drop ejectors of the head.
PWA (Partial Width Array) inkjet printers, which carry out printing by moving a recording sheet in a subscanning direction while scanning a recording head in a main scanning direction, can employ a multipass recording method. Therefore, variation in the ejecting characteristics of the respective nozzles of the recording head can be dispersed, and deterioration in image quality can be prevented. A multipass recording method is a method in which, by moving the recording medium by minute amounts in the direction in which the nozzles of the recording head are lined-up and scanning the recording head plural times (multipass) in the direction orthogonal to the direction in which the nozzles are lined-up, a thinned-out image is complementarily recorded in the same region of the recording medium by different nozzles groups and the image is completed.
However, in a so-called FWA (Full Width Array) inkjet printer which has an elongated recording head having substantially the same width as the width of a recording sheet and which carries out recording while keeping the recording head fixed and conveying only the recording medium, basically, the head is fixed and the recording sheet is conveyed. Therefore, such multipass printing cannot be carried out, and defects in liquid drop ejectors become particularly great problems.