Image forming apparatus and method of arranging sheet detector

A method of arranging a detector in an image forming apparatus, the method comprising the steps of:

• forming a toner image onto a recording medium under a prescribed image forming condition;
• fixing the toner image borne on the recording medium thereonto by heating the recording medium based on target fixing temperature;
• detecting the type of recording medium, the type being used in setting at least one of the image forming condition and the target fixing temperature;
• conveying the recording medium at a prescribed process line speed at least until the tip of the recording medium reaches a fixing device after the tip of the recording medium reaches a detector;
• and
• arranging the detector to establish Tb >Ta,
• where Ta represents a time period needed for a fixing device to reach a setting of fixing temperature allocated to the recording medium with its tip detected by the detector after detection of the tip and Tb represents a time period needed by the recording medium to reach the fixing device after detection of the tip.

A method of arranging a detector in an image forming apparatus, the method comprising the step of:

• forming a toner image onto a recording medium under a prescribed image forming condition;
• fixing the toner image borne on the recording medium thereonto by heating the recording medium based on target fixing temperature;
• detecting a smoothness of the surface of the recording medium by detecting an quantity of regular light emitted to the recording medium from a light source and reflected in a specular direction therefrom;
• conveying the recording medium at a prescribed process line speed at least until the tip of the recording medium reaches a fixing device after the tip of the recording medium reaches a detector;
• and
• arranging the detector to establish Td >Tc,
• wherein Tc represents a time after a tip of the recording medium is detected by the smoothness detector until the detected value is fixed and Td represents a time until the image forming device starts image forming operation based on the image forming condition allocated to the recording medium after detection of the tip.

An image forming apparatus, comprising:

• an image forming device to form a toner image on a recording medium under a prescribed image forming condition;
• a fixing device to fix the toner image borne on the recording medium thereonto by heating the recording medium based on a target fixing temperature;
• and
• a detector to detect the type of recording medium, the type being used in setting at least one of the image forming condition and the target fixing temperature,
• wherein the detector is a smoothness detector configured to detect a smoothness of the surface of the recording medium by detecting a quantity of regular light emitted to the recording medium from a light source and reflected in a specular direction therefrom,
• wherein the target fixing temperature is based on an average of the detected values detected by the smoothness detector multiple times within a prescribed time period, and
• wherein Tb >Ta,
• where Ta represents a time period needed to reach a setting of fixing temperature allocated to the recording medium with its tip detected by the detector after detection of the tip and Tb represents a time period needed for the recording medium with its tip detected by the detector to reach the fixing device after detection of the tip.