The influence of paper thickness on photoelectric switches

The influence of paper thickness on photoelectric switches
Analysis of the correlation between paper thickness and photoelectric switch
The thickness of paper directly affects the detection performance of photoelectric switches by changing the transmission intensity of light signals. When the paper is thick, the light transmittance decreases and the light intensity received by the receiver weakens; On the contrary, when the paper is thin, the light intensity increases. This difference is recognized by the detection circuit of the photoelectric switch, which triggers the corresponding control logic, such as distinguishing between normal single sheet and abnormal double sheet states in double sheet detection
The working principle of photoelectric switch for detecting paper thickness
Optical signal modulation and reception: The emitter of the photoelectric switch (such as an infrared emitter tube) emits a light beam, and the paper acts as a barrier to affect the transmission of light. The receiver (such as a photodiode) outputs an electrical signal based on changes in light intensity, which is processed by a circuit to determine the thickness of the paper.
Threshold judgment mechanism: The detection circuit compares the received signal with the reference voltage to determine whether the paper thickness exceeds the set range. For example, thick paper weakens the received signal and triggers the corresponding relay action
Key factors affecting the detection accuracy of photoelectric switches
Characteristics of paper itself
Thickness uniformity: Uneven or fluctuating paper surfaces may cause unstable optical signals, affecting detection consistency.
Material and color: High gloss or dark paper may reflect or absorb light, interfering with accurate measurement of transmitted light intensity.
Parameters of photoelectric switch
Light source wavelength: The infrared wavelength has a significant difference in penetration ability for different types of paper, so it is necessary to choose an appropriate light source based on the type of paper.
Detection distance: If the distance between the transmitter and receiver is too large, it will reduce the intensity of the optical signal and needs to be calibrated to the detection range.
Environmental interference
External light source: Strong light or strobe light sources may be superimposed on the detection beam, leading to misjudgment.
Dust and water vapor: Surface contamination of optical components can weaken light transmittance and require regular cleaning and maintenance.
Practical application and optimization suggestions
Double sheet detection scenario: By utilizing the sensitivity of photoelectric switches to thickness changes, paper overlap (such as double or multiple sheets) can be quickly identified, which is widely used in automatic paper feeding control of printing and packaging machinery.
Sensor selection: For high-precision scenarios, laser ranging sensors (such as ZLDS100 series) are recommended, with a resolution of up to 0.001mm, suitable for detecting thin or coated paper.
Circuit calibration: Compensate for optical signal fluctuations caused by differences in paper material by adjusting the reference voltage or using an automatic gain control (AGC) circuit