Registration adjustment method for image forming apparatus and image forming apparatus

A registration adjustment method for an image forming apparatus,

• the image forming apparatus including:
• an imaging process unit that forms a color visible image by writing a latent image on each of a plurality of image carriers with laser light from an optical scanning device, developing the latent images on the image carriers to form visible images of respective colors on the image carriers, and superimposing and transferring the visible images of respective colors on the image carriers onto a recording medium;
• and a registration correction unit that detects displacement of test patterns of each color in the color visible image as a registration adjustment value and corrects positions of the superimposed and transferred visible images of respective colors based on the registration adjustment values,
• the registration adjustment method comprising:
• a registration step of measuring and determining the registration adjustment value for each color;
• and
• a printing step of correcting the registration adjustment value for each color determined in the registration step so as to print the color visible image,
• wherein the registration step and the printing step include:
• a first temperature detecting step of detecting, by using a first temperature detecting unit, a temperature near a polygon mirror that reflects and scans the laser light in the optical scanning device;
• and
• a second temperature detecting step of detecting, by using a second temperature detecting unit, an internal ambient temperature of the image forming apparatus at a location that is outside the optical scanning device and that is farther away from the polygon mirror than the first temperature detecting unit is;
• wherein, during the printing step,
• a difference between the temperature detected by the first temperature detecting unit in the registration step and the temperature detected by the first temperature detecting unit in the printing step is obtained;
• and
• a difference between the temperature detected by the second temperature detecting unit in the registration step and the temperature detected by the second temperature detecting unit in the printing step is obtained, and
• wherein a registration correction operation step of correcting the registration adjustment values is executed based on a change in the temperature detected by the first temperature detecting unit and a change in the temperature detected by the second temperature detecting unit.