Noise reduction of a laser printer using SEA and FEM

Office machines (printers, copy machines, fax, etc) are essential tools in both business and private scenes. The features required for these machines are high quality print images, high speed printing, small size, and low noise, etc. In recent years, the noise of office machines is especially undesirable. To reduce the noise of the office machines, many approaches have been used. Most of them are FEM and experimental modal analysis for vibration problems. Those approaches are effective, while they are difficult to be applied to the cases that connections among mechanical parts are weak and properties of parts are irregular. In this paper, SEA (statistical energy analysis) is applied for noise reduction of a laser beam printer. In our process using SEA, first, the laser printer was subdivided into some parts (SEA subsystems). Next, the experimental SEA(ESEA) was carried out to obtain the SEA parameters (CLFs and ILFs). After that, the acoustic contribution factor for each SEA subsystem was evaluated by using the sound measurement and the ESEA parameters. The factors indicate how vibration energy of each subsystem contributes to the sound power level at the evaluation positions. Then, the perturbation method was adopted in order to decide which SEA parameter should be changed to effectively reduce sound power level of the laser printer. By using this method, the CLFs between the two pairs of subsystems were extracted and it was shown that these CLFs should be reduced to smaller values. In order to verify the validity of the processing above, we modified some parts of the laser printer in order to reduce the values of the two CLFs extracted by the perturbation method. The experiment showed 4.1 dB reduction of sound power level at target peak in the frequency domain. In conclusion, we reached the result that the combination of the SEA approach and the perturbation method is effective for noise reduction of a laser printer. This combination can be also applicable for noise reduction of the other kinds of office machines. Then we also confin-ned the change of the CLFs due to the structural could be predicted by 'PAM-VA One'.