The present invention claims priority under 35 U.S.C. § 119 to Japanese Application No. 2019-122958 filed Jul. 1, 2019, the entire content of which is incorporated herein by reference.

BACKGROUND

Technological Field

The present invention relates to an inkjet image forming apparatus and an image forming condition changing method.

Description of the Related Art

In recent years, as an apparatus that records a high-definition image on various recording media such as paper and cloth, an image forming apparatus by an inkjet method of forming an image on a recording medium by discharging an ink droplet from an inkjet head (hereinafter, referred to as an “inkjet image forming apparatus”) is widely used.

In an inkjet image forming apparatus, there is proposed an intermediate transfer type in which an ink droplet discharged from an inkjet head is formed as an image on an intermediate transfer body such as an intermediate transfer belt, and the formed image is transferred to a recording medium at a transfer nip (for example, see P 2012-96546 A). With this intermediate transfer type, an amount of the ink droplet can be suppressed in advance, and the ink droplet can be crushed by the transfer pressure of the transfer nip and expanded to a desired size (diameter). In other words, an image with high image coverage can be formed with a small amount of the ink droplet.

An inkjet image forming apparatus of an intermediate transfer type has, for example, a configuration using ink that is cured (thickened) by an active energy ray (for example, an ultraviolet ray) and using a transfer body having active energy ray transmissivity in order to ensure the transferability of an image to a recording medium. In this configuration, an image (ink droplet) clamped and pressed (nipped) at a transfer nip is irradiated with an active energy ray to adjust the viscosity of the ink droplet.

Incidentally, in a case where the surface energy of the ink used for image formation is low (that is, the viscosity is high), the temperature of a position where the ink droplet has landed on the intermediate transfer body is different from target temperature, and as a result, a deviation in a spread (diameter) of the ink droplet occurs. In addition, in a case where unevenness in a moving speed of the intermediate transfer body on which an image is formed occurs, a deviation occurs between the position where the ink droplet has landed on the intermediate transfer body and a target landing position. There is a problem that when these deviations occur, the quality of the image formed on the intermediate transfer body deteriorates, and then the quality of the image finally transferred to the recording medium at the transfer nip deteriorates.

SUMMARY

An object of the present invention is to provide an inkjet image forming apparatus and an image forming condition changing method capable of suppressing deterioration in the quality of an image formed on a transfer body.

To achieve the abovementioned object, according to an aspect of the present invention, an inkjet image forming apparatus reflecting one aspect of the present invention comprises: an image former that forms an image on a transfer body by discharging an ink droplet from an inkjet head; and a hardware processor that detects a landing state of the ink droplet that has been discharged and landed on the transfer body and changes an image forming condition when the image is formed so that a detected landing state approaches a target landing state.

