Recording material characteristic detecting device and image forming device

A recording material characteristic detecting device that irradiates a first light having a first characteristic and a second light having a second characteristic to a sheet type recording material carried along a predetermined carrying path and detects a transmitted light generated when the first light transmits through the recording material and a reflection light generated when the second light is reflected by the recording material, and detects a characteristic of the recording material, the recording material characteristic detecting device comprises:

• a reflection light source that irradiates the second light toward the carrying path;
• a transmitted light source that irradiates the first light toward the carrying path;
• a reference plate for reflection light arranged oppositely to the reflection light source across the carrying path to reflect the second light;
• and
• a light detector arranged oppositely to the reference plate for reflection light across the carrying path to detect at least a reflection light generated in response to reflection of the second light, wherein
• the reference plate for reflection light has a higher reflectivity for light having the second characteristic than for light having the first characteristic, and the reference plate is arranged such that light from the reflection light source that is reflected by the reference plate is reflected to the light detector.