I. Core Technical Principles Halogen cycle mechanism: By the high-temperature luminescence of the tungsten filament (with a color temperature of approximately 3000K), it reacts with halogen gases such as iodine and bromine, forming a dynamic equilibrium halogen cycle. This inhibits the evaporation of the tungsten filament and extends the lifespan of the lamp tube to 2000-4000 hours. Halogen lamps specifically designed for copiers (such as bromine tungsten lamps/chlorine tungsten lamps) are made of fine-tube quartz glass with uniform tube wall temperature and are compatible with selenium-tellurium alloy photoconductors (with a sensitivity of 400-550nm), ensuring spectral matching. Segmented light emission design: The filaments are arranged non-uniformly (such as dense at both ends and sparse in the middle), matching the characteristics of the optical system, compensating for the attenuation of light transmittance at the edge of the lens, and achieving uniform illuminance of the original document. For instance, although the Canon NP-9030 uses a laser light source, most copiers still rely on halogen lamps for slit exposure.
Ii. Key Technical Parameters and Performance Indicators Power and size: Power range 350W-850W, voltage compatible with 107V-240V, diameter approximately 0.3cm, length compatible with A3/A4 specifications. Single-tube, double-tube and triple-tube structures support different format requirements, with a lifespan of up to 250,000 sheets (approximately 2,000 to 4,000 hours). Spectral characteristics: Color rendering index Ra>95, close to the daylight spectrum, suitable for precise color matching. The proportion of infrared radiation is high. It is necessary to combine reflectors and filters to optimize the light efficiency and reduce the impact of thermal radiation on the glass of the draft table. Energy efficiency and lifespan: The luminous efficiency is approximately 15-20 lumens per watt. Although it is lower than that of LED, it has a significant cost advantage. Metal halide lamps can achieve multi-peak spectra (such as 403nm+417nm ultraviolet light) by adding halides like iron/gallium, and support UV curing scenarios (such as automotive interior printing).
Iii. Safety Regulations and Key Operating Points Installation and maintenance Power must be cut off before operation to avoid electric shock. When replacing, wait for the lamp tube to cool down and wear gloves to prevent oil stains from affecting the uniformity of light emission. Regularly clean the lamp tubes, reflectors and filters to ensure the unobstructed heat dissipation channels. The machine is equipped with a fan for forced heat dissipation, keeping the temperature ≤50℃. The reflector adopts an elliptical cross-section design, with the filament placed on the focus line, optimizing beam convergence and enhancing the uniformity of illuminance. Electrical safety: Complies with IEC 60598 standard, insulation resistance ≥2MΩ, withstand voltage test ≥1.5kV. Goggles must be worn during operation to prevent damage from strong light.
