Image forming device and image forming method

An image forming device provided with an image carrier that carries a developed image obtained by developing an electrostatic latent image based on image data with a developing agent, and a transfer unit that performs a transfer process to transfer the developed image to a paper sheet, in which the transfer process is capable of being performed on the paper sheet a plurality of times, the image forming device comprising:

• a measurement unit provided with at least one light source, configured to illuminate the paper sheet with light, receive the light reflected from the paper sheet, and measure intensity of the light;
• a setter configured to, before each of the plurality of times of the transfer processes, calculate a moisture content on a surface of the paper sheet from the light intensity measured by the measurement unit, and set a transfer condition of the transfer unit in accordance with the moisture content on the surface of the paper sheet;
• a paper feed cassette configured to contain the paper sheet;
• a feed roller configured to take up the paper sheet contained in the paper feed cassette;
• and
• a stop roller configured to temporarily stop the paper sheet before performing the transfer process on the paper sheet, wherein:
• the measurement unit includes a first measurement unit and a second measurement unit;
• the first measurement unit performs measurement about the paper sheet taken out of the paper feed cassette by the feed roller and temporarily stopped by the feed roller;
• the second measurement unit performs measurement about the paper sheet stopped by the stop roller;
• and
• the setter sets the transfer condition in a first transfer process among the plurality of transfer processes by using the light intensity measured by the first measurement unit, and sets the transfer condition in a second or subsequent transfer process among the plurality of transfer process by using the light intensity measured by the second measurement unit.

An image forming method in an image forming device provided with an image carrier that carries a developed image obtained by developing an electrostatic latent image based on image data with a developing agent, and a transfer unit that performs a transfer process to transfer the developed image to a paper sheet, in which the transfer process is capable of being performed on the paper sheet a plurality of times, the image forming method comprising:

• first measuring intensity of received light by illuminating the paper sheet contained in a paper feed cassette with light from at least one light source and receiving the light reflected from the paper sheet;
• second measuring intensity of received light by illuminating the paper sheet stopped by a stop roller configured to temporarily stop the paper sheet before performing the transfer process on the paper sheet;
• and
• before each of the plurality of times of the transfer processes, setting a transfer condition of the transfer unit in accordance with a calculated moisture content on a surface of the paper sheet by calculating the moisture content on the surface of the paper sheet from the intensity of the received light measured in the measuring,
• wherein the transfer condition in a first transfer process among the plurality of transfer processes is set by using the light intensity measured by the first measuring, and the transfer condition in a second or subsequent transfer process among the plurality of transfer processes is set by using the light intensity measured by the second measuring.