The main types of fork sensors are classified based on their detection principle and application. The most common types are photoelectric fork sensors, ultrasonic fork sensors, capacitive fork sensors, and label fork sensors (also called label gap sensors). Each type is designed for specific materials, object sizes, and working environments, but all share the same U-shaped design that combines the emitter and receiver in one compact housing for precise alignment and reliable detection.
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Photoelectric Fork Sensors – These are the most widely used type. They operate on a through-beam optical principle, where an infrared or visible light beam travels from the emitter to the receiver. When an object interrupts the beam, the sensor detects its presence. Photoelectric fork sensors are ideal for detecting small parts, wires, or edges in packaging, labeling, or assembly machines.
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Ultrasonic Fork Sensors – These sensors use sound waves instead of light to detect transparent or reflective materials that optical sensors might miss. They are perfect for label detection, transparent film, or plastic materials, where light-based sensors may struggle due to reflections.
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Capacitive Fork Sensors – These detect objects based on changes in capacitance when a material enters the fork gap. They can sense both metallic and non-metallic materials and are often used in liquid or granular level detection applications.
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Label Fork Sensors (Label Gap Sensors) – A specialized optical or ultrasonic type designed specifically for label dispensing systems. They detect the gap between labels on a backing tape to ensure accurate label application on packaging lines.
In simple terms, the main types of fork sensors are photoelectric, ultrasonic, capacitive, and label sensors — each chosen based on what material or object needs to be detected. All are compact, fast, and ideal for high-precision industrial automation tasks.
There are mainly three types of fork sensors used in industrial automation — optical fork sensors, ultrasonic fork sensors, and infrared fork sensors. Each type follows the same working structure, where a transmitter and receiver are placed opposite each other in a U-shaped frame. When an object passes through the slot, it interrupts the beam and the sensor detects it. This simple yet precise principle makes fork sensors ideal for label detection, counting, and edge positioning in packaging and printing machines.
The optical fork sensor is the most common type used in manufacturing industries. It works using a visible or infrared light beam. When the light is blocked by an object, the sensor sends a signal to indicate detection. These sensors are compact, easy to mount, and deliver accurate switching at high speeds. Optical fork sensors are perfect for applications like label detection, mark sensing, and component counting, where precision and fast response are required.
The ultrasonic fork sensor works on sound wave technology instead of light. It detects materials that are transparent, reflective, or uneven in texture. Because light sensors may fail to recognize such objects, ultrasonic types are preferred in packaging lines using transparent film, plastic sheets, or glass surfaces. They are also more stable in environments affected by light reflections or color variations.
Finally, infrared fork sensors are designed for dusty, humid, or outdoor industrial conditions. They are less affected by dirt buildup and maintain reliable performance even when exposed to contamination. Infrared sensors ensure strong detection where optical sensors might face interference. In short, all three types — optical, ultrasonic, and infrared — play vital roles in automation, helping industries achieve accurate detection, high speed, and long-term reliability.