| 摘要 |
PROBLEM TO BE SOLVED: To obtain an image forming device capable of excellently performing the maximum density control of an image based on the measurement of the gray level of a gray level patch and gradation control based on the measurement of the gray level of a gradation pattern even when light is leaked from the outside by opening/closing the upper cover of a device in a serviceman mode. SOLUTION: This device is provided with either or both of a maximum gray level control means deciding the maximum density characteristic of a gray level control means based on relation between the gray level of the gray level patch formed on a transfer drum 5 and the detected gray level by an optical sensor 10 for gray level control and a halftone control means deciding the gradation correction characteristic of a gradation correction means based on relation between the density of the formed gradation pattern and the detected gray level by the sensor 10. An optical sensor 25 for detecting leakage light is set inside the device. In the case of detecting the leakage light, the controlled result by the maximum gray level control means or the gradation correction means is neglected, and either or both of the maximum gray level control characteristic or the gradation correction characteristic previously set are selected. |
