Recently, with copiers and printers becoming faster and image quality increasing,higher rigidity has been required of the frame structure, and square pipe members with excellent rigidity in torsional. moment compared to cohventional channel members are being used for some models. For the square pipe members,our company has developed a method to make sheet metal into a rectangular form through press working and fastening the joints of the ends of the sheet metal through the protrusions of male and female portions. The dimensional setting of the male/female protrusion of the fastening is optimized using the quality engineering method. The main objective of this fastening is to improve torsional rigidity, and we evaluated it on the basis of the shearing strength of the fastened portion in consideration of the actual use of square pipe members. This enabled evaluation with simple test pieces. The basic function was varied against load, and the error factor was made for an increase or a decrease of load to obtain the ideal function required for the fastening. The control factors were all dimensional values of the male/female protrusion. In the first experiment, the reproducibility of sensitivity was low because of the method of taking factors and level, but by conducting the experiment again while changing factors and level, good results were obtained. Using the quality engineering method made it possible to simplify the test and reduce the development time,

In the manufacturing field, demand is rising for the construction of a new quality control mechanism that can assure product quality more reliably and efficiently than conventional mechanisms. To achieve this, we collsidered that it would be effective to use on-line quality engineering (On-QE). On the basis of research results obtained using the existing line as a model process reported in the previous two papers, we reviewed radically the conventional inspection system by means of process capability indexes and OK/NG binary judgment, and comprehensively introduced a quality control system using On-QE based on a loss function. We incorporated the idea of On-QE in "setting cycle time/measuring place" at the stage of line design, and developed and introduced a "total management system" to realize fast adjustment and reflection of the optimum measuring cycle required by On-QE. As a result, we achieved a manufacturing line with the loss function L, which was overwhelmingly smaller than the conventional one, at the start of mass-production. We proved that On-QE promotion activities to reduce social loss resulted in reducing faults in our company.

In motor sports, telemetering is often used to evaluate a racing car's condition by monitoring various characteristics. Especially in an endurance race, accurate judgments of conditions are required because an error by technical personnel can lead to retirement from a race. It is, therefore, considered that constructing a vehicle abnormality detection system is effective for enhancing the accuracy of judgments made by technical personnel and competitiveness. In constructing the system to detect abnormalities in a vehicle during a race, we investigated the possibility of applying MT system for data obtained in the 1999 Le Mans 24-Hour Race and Le Mans Fuji 1000 km Race. As a result, we were able to verify the utility of the vehicle abnormality detection system using data from actual races, and show that application of the MT system in the motor sports field would be useful for improving competitiveness. For the analysis, which is also useful in other fields, it is effective to divide a unit space by characteristic values, and it is possible to incrementally increase the unit spaces in accordance with race progress as the number of laps increases. In response to the problem that dispersion becomes zero with in a unit space, we set the allowable fluctuation range from characteristic values and measuring accuracy, and changed the data within that range, thus making it possible to use all of the characteristic values.

The developing process in the electrophotographic system used for copiers and printers attaches toner electrostatically to a latent image written on a photoreceptor;however, we tried to analyze the basic functions of the developing process in the electrophotographic system by combining a newly developed simulator of toner particle dynamics and a quality engineering method. We considered two basic functions: fidelity reproducibility to the latent image and distribution fluctuation of toner in the developing process. For the latter, we calculated the S/N ratio on the cumulative frequency axis of the distribution for selective developing properties of toner having a particle size distribution. With the simulator of toner particle dynamics, we allocated multiple parameters as factors to the L18 orthogonal array, and simultaneously analyzed the above two basic functions through a numerical calculation using the simulator. To verify the reliability of the numerical calculation, we measured factors that had major effects using the experiment bench. As a result, it was clarified that the same trend is shown by the numerical calculation result and the measurement result. As shown in this case, we consider that we can proceed with technological development efficiently by combining both methods.

The process of press stamping provides excellent stamping efficiency and is indispensable for reducing cost through mass-production. Although it is a simple process for stamping work using punches and dies, it involves acomplicated mechanism because it is accompanied by the destruction of materials and plastic deformation. For this reason, a theoretical analysis is difficult, and in many cases, the stamping conditions are determined through research centering on qualitative methods and experience of field engineers. In this study, therefore,we investigated the possibility of applying quality engineering in press stamping and optimizing stamping conditions. As a result, it was clarified that quality engineering could be applied and the punch material and the plate holding force had major effects on the S/N ratio, and we could determine the optimum stamping conditions. We could also improve the heights of burrs, a quality characteristic.

As part of our company's attempts to improve the Development (Design) Division, we have promoted the introduction and the dissemination of Quality Engineering (QE). In this study, we introduce the actual situation of QE introduction,and describe our thinking on the importance of the commitment and the role of top management toward using and promoting QE on the basis of our experlence.

Based on the results of studies at Fuji Xerox Co., Ltd., we verified the effectiveness of the success factors (KFS8 items) of QE promotion, and made new discoveries through a long process of trial and error toward the use and the progress of quality engineering.