Apparatus and method for measuring recording medium thickness, apparatus and method for detecting multi-feed of recording medium and apparatus and method for forming image

A recording medium thickness measuring apparatus comprising:

• an output value detection unit that detects an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• an output value storage unit that stores the output value detected by the output value detection unit while the recording medium is passing through the predetermined position of the transport path;
• and
• a calculation unit that calculates the thickness of the recording medium based on the output value stored in the output value storage unit and the output value detected by the output value detection unit while the recording medium is passing through the predetermined position of the transport path.

A recording medium thickness measuring apparatus comprising:

• an output value detection unit that detects an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• a second output value storage unit that stores a second output value detected by the output value detection unit while the recording medium is passing through the predetermined position of the transport path;
• and
• a calculation unit that determines whether or not the output value detected by the output value detection unit is influenced by a factor different from the thickness of the recording medium, and when the output value is not influenced by the factor different from the thickness of the recording medium, calculates the thickness of the recording medium based on a first output value detected by the output value detection unit before passage of the recording medium and after passage of an immediately preceding recording medium in the predetermined position of the transport path and the second output value detected by the output value detection unit while the recording medium is passing through the predetermined position, while when the output value is influenced by the factor different from the thickness of the recording medium, calculates the thickness of the recording medium based on the second output value stored in the second output value storage unit and the second output value detected by the output value detection unit while the recording medium is passing through the predetermined position of the transport path.

An image forming apparatus comprising:

• an output value detection unit that detects an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• and
• a multi-feed determination unit that determines occurrence/nonoccurrence of multi-feed by calculating the thickness of the recording medium based on a first output value detected by the output value detection unit before passage of the recording medium and after passage of an immediately preceding recording medium in the predetermined position of the transport path, and a second output value detected by the output value detection unit while the recording medium is passing through the predetermined position,
• when the multi-feed determination unit determines that multi-feed has occurred, processing different from processing upon determination of nonoccurrence of multi-feed being performed.

A method for measuring recording medium thickness comprising:

• detecting an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• storing the output value detected while the recording medium is passing through the predetermined position of the transport path;
• and
• calculating the thickness of the recording medium based on the stored output value and the output value detected while the recording medium is passing through the predetermined position of the transport path.

A method for measuring recording medium thickness comprising:

• detecting an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• storing a second output value detected while the recording medium is passing through the predetermined position of the transport path;
• and
• determining whether or not the detected output value is influenced by a factor different from the thickness of the recording medium, and when the output value is not influenced by the factor different from the thickness of the recording medium, calculates the thickness of the recording medium based on a first output value detected before passage of the recording medium and after passage of an immediately preceding recording medium in the predetermined position of the transport path and the second output value detected while the recording medium is passing through the predetermined position, while when the output value is influenced by the factor different from the thickness of the recording medium, calculates the thickness of the recording medium based on the stored second output value and the second output value detected while the recording medium is passing through the predetermined position of the transport path.

A method for forming image comprising:

• detecting an output value which fluctuates in accordance with thickness of a recording medium passing through a predetermined position of a transport path;
• and
• determining occurrence/nonoccurrence of multi-feed by calculating the thickness of the recording medium based on a first output value detected before passage of the recording medium and after passage of an immediately preceding recording medium in the predetermined position of the transport path, and a second output value detected while the recording medium is passing through the predetermined position,
• when it is determined that multi-feed has occurred, processing different from processing upon determination of nonoccurrence of multi-feed being performed.