In modern copiers and scanners, the ability to automatically detect the size of a document greatly enhances office efficiency. This feature allows the device to automatically adjust the scanning or copying settings to match the size of the document once it's detected in the scanning area. But how is this achieved?
How to determine the size of the original on the manuscript table?
In general, the original size is determined by the manuscript reading unit (CIS or CCD) + sensor method. Depending on the model, the components used will also be different. In Konica Minolta equipment, the original FD direction size detection uses a fixed original size sensor in the optical compartment.
Like this:
This:
And this:
The CD direction will trigger detection twice
- Detection when the angle sensor is activated
- Detection is performed again when the original cover sensor is activated
Angle sensors generally use a photoelectric sensor + a spring-loaded arm, like this:
The original cover sensor has different parts depending on the model. There are currently two types: photoelectric sensor and magnetic sensor. Activate twice, light the exposure light twice to illuminate the original, and reflect the light onto the CCD board to determine the size of the original in the CD direction. With CD and FD, the original size can be determined!
Whenever you see a magnet (magnet) on the original cover or document feeder, it means that it uses a magnetic sensor as the original cover sensor!
Note:
If there is a problem with the angle sensor activation angle or the original cover sensor activation timing, it will affect the determination of the original size, and the actual size will be inconsistent with the panel display. In this case, you can adjust the activation arm spring and the document feeder position appropriately for correction (personal experience)
How to determine the original size on the document feeder?
Compared with the draft table, the principle of the draft feeder's original size detection is relatively simple. The FD direction size uses a photoelectric document length sensor, and the CD direction size uses a document width sensor (the low-speed machine draft feeder generally uses a group of photoelectric sensors, and the medium- and high-speed machine draft feeder uses a VR variable resistor)
Knowledge supplement:
CIS: A contact photoelectric conversion device, which uses a row of built-in LED light-emitting diodes for illumination and directly contacts the surface of the original to read image data. Scanners using CIS technology have no additional optical components, and the moving parts are light and small, so the entire scanner can be made very light and thin. The resolution is 300 to 600.
CCD: A semiconductor chip. Scanners that use CCD as a photosensitive element need to transmit images to the CCD chip through an optical system composed of a series of lenses, reflectors, etc., so the volume is generally large. The resolution can reach 300 to 1200 or higher.
Difference: CCD is large in size and high in cost, but has high resolution and a large scanning range; CIS is small in size and relatively low in cost, but has low resolution
Conclusion
The automatic detection of document size in modern copiers and scanners, especially those from Konica Minolta, relies on a combination of advanced sensors such as CIS, CCD, and magnetic sensors. These technologies work together to determine the exact dimensions of the original document, ensuring accurate scanning and copying. Proper maintenance, including the adjustment of sensors, is crucial to keep this system functioning effectively.