Research On Automatic Detection Device Of Optical Scanning System Of Laser Printer

The optical scanning system is the core component of the laser printer.It completes the photoelectric information conversion by emitting the laser beam,which directly affects the printing effect of the printer.The system is composed of a lens group.The optical design,manufacturing and installation errors will affect the imaging quality of the system,thereby changing the shape of the spot of the outgoing laser beam and affecting the printing quality.Therefore,the detection of the outgoing laser beam spot can directly reflect the error of the optical scanning system of the laser printer,and become a technical means of its quality monitoring.At present,the detection of the optical scanning system adopts the method based on surface detection and optical image quality evaluation,which cannot directly reflect the imaging quality,and relies on manual operation,which reduces the detection efficiency and accuracy.How to realize the high-efficiency and high-precision automatic detection of the outgoing laser beam spot,and determine the imaging quality of the system through the detection results,so as to improve the detection efficiency and ensure product quality,this research is of great significance to the development of laser printers.This subject takes the automatic detection device of the optical scanning system of the laser printer as the research object.First,based on the analysis of the optical principle of the lens group of the optical scanning system,the detection method is determined and the control parameters are established;the image sensor is used to realize the acquisition and processing of the spot image;A motion control platform is built to realize the automatic detection process with the help of a high-precision control system.The main research contents of the paper are as follows:1.Imaging features and detection methods of optical scanning systems.According to the consistency of the image spot and the characteristics of the image plane,the spot size at the key position on the image plane is determined as the basis for judging the imaging quality of the system.According to the principle of linear imaging,the corresponding position of the rotating mirror rotation angle and the camera acquisition point is determined by Zemax multi-structure simulation.relationship,which provides the basis for the parameters of the motion control system;2.A light spot test device was built.According to the detection requirements and technical indicators,the overall design scheme is proposed,and the device construction is completed,including the design of the beam deflection structure,the beam receiving structure and the hardware selection.The actual experiment shows that the positioning accuracy of the beam deflection structure is 0.03°,and the positioning accuracy of the beam receiving structure is 0.01 mm,which can realize the accurate collection of the light spot;3.The processing method of the spot image.According to the characteristics of spot image imaging,the common spot centroid detection and spot size calculation methods are analyzed,and the target spot diameter is achieved by using bilateral filtering,threshold segmentation,spot centroid least squares circle fitting method detection,second-order moment method and other algorithms.detection;4.Control strategy and algorithm of the control system.According to the principle of optical path propagation,the parallel synchronous control strategy is adopted,and the S-shaped acceleration and deceleration curve is used to realize the optimization of the motor motion state.In view of the inaccurate positioning caused by the mechanical structure of the ball screw slide table,a fully closed-loop control method is used to compensate for the error.High-precision automatic detection is realized.