Electrophotography – Internal machine environment
Reexamination Certificate
2002-07-05
2004-02-24
Pendegrass, Joan (Department: 2852)
Electrophotography
Internal machine environment
C381S071100
Reexamination Certificate
active
06697584
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image formation apparatus and tone quality improving method of image formation apparatus.
BACKGROUND OF THE INVENTION
In Japanese Patent Application Laid-Open No. 9-193506, there is disclosed an invention relating to “Noise masking apparatus and noise masking method in image formation apparatus”. This invention relates to a noise masking apparatus for a laser beam printer, a copying machine or the like, which has a sound-producing object having a drive mechanism, being a source of noise at the time of operation and generating masking sound for masking this noise, and a masking sound control unit which controls this sound-producing object to generate masking sound of a frequency in the range of including the main component frequency of the noise, so as to reduce uncomfortable feeling due to the noise.
In Japanese Patent Application Laid-Open No. 10-232163, there is disclosed an invention relating to “Tone quality evaluation apparatus and tone quality evaluation method”. This is for enabling evaluation of only the roaring sound, which is a gloomy noise of low-frequency random noise generated by an air flow system, such as exhaust sound, from the noise constituted by the sound of various tones of the image formation apparatus, to make the correspondence with psychological annoyance easy.
Similarly, in Japanese Patent Application Laid-Open No. 10-253440, there are disclosed a tone quality evaluation apparatus and a tone quality evaluation method which extracts only creaking sound, which is recognized as offensive sound to the ear and is a persistent pure tone quality generated by a scanner motor or a charging device, from noise constituted of sound of various tones of the image formation apparatus and performs evaluation.
In Japanese Patent Application Laid-Open No.10-253442, there are disclosed a tone quality evaluation apparatus and a tone quality evaluation method which makes it possible to evaluate only “sha” sound, which is a high-frequency random noise due to rubbing of the sheet of paper, from the noise constituted of sound of various tones of the image formation apparatus.
In Japanese Patent Application Laid-Open No. 10-267742, there are disclosed a tone quality evaluation apparatus and a tone quality evaluation method which makes it possible to evaluate only the moaning sound consisting of pure sound having peaks in a plurality of adjacent frequencies especially due to beat of the drive system, from the noise constituted of sound of various tones of the image formation apparatus.
In Japanese Patent Application Laid 7Open No.10-267743, there are disclosed a tone quality evaluation apparatus and a tone quality evaluation method as described below. That is, in the noise constituted of sound of various tones of the image formation apparatus, if there is no pure sound or moan, that is, when there is no protruding component in the frequency wavelength, it is felt smooth. Based on this, when the annoyance felt by human is generally referred to smoothness, the apparatus and the method can-evaluate the smoothness of sound.
According to the invention described in Japanese Patent Application Laid-Open No. 9-193506, it is considered that the noise level is increased, by adding the masking sound to this generated noise, not by reducing the generated noise.
There is a disadvantage in that it requires a sound-producing object for generating the masking sound, and a control unit and a speaker for generating the masking sound only while the sound to be masked is generated, thereby increasing extra space in the layout of the machine and increasing the cost considerably.
In the series of inventions relating to the above-described tone quality evaluation apparatus and tone quality evaluation method, only the tone quality evaluation method is proposed, and a tone quality improving method of the actual product is not described.
Recently, from a viewpoint of softness to the environment, there is an increasing interest in the noise problem, and there is an increasing demand for solving the noise problem of the OA equipment in offices. Therefore, attempts have been made for quieting down the OA equipment, and considerably quiet environment has been achieved than before. Currently, as a method of evaluating the noise in the OA equipment, there are generally used a sound power level and a sound pressure level (ISO7779). However, these levels indicate values of acoustic energy generated by the office equipment such as a copying machine and a printer, and hence the correlation between these values and the human's subjective discomfort with respect to the noise may not be good.
For example, when sounds having the same value of the sound pressure level (equivalent noise level Leq: a value obtained by averaging the energy over the whole measuring time) are heard and compared, there may be a difference in the discomfort due to a difference in the sound frequency distribution or the existence of impulsive sound. Further, even if the value of the sound pressure level is small, but if a high-frequency component or a pure sound component is included, the sound may be felt uncomfortable.
Therefore, in order to improve the future office environment, not only the evaluation and reduction of the OA equipment by the sound power level and the sound pressure level, but also evaluation and improvement of the tone quality are both necessary. For the evaluation and improvement of the tone quality, it is necessary to carry out quantitative measurement of the tone quality for understanding the current situation, and to measure how much improvement has been achieved before and after the improvement. However, since the tone quality is not a physical quantity, quantitative measurement cannot be carried out. Hence, it is difficult to set a target value.
When the tone quality is to be evaluated by human, qualitative expression is obtained, such as “the tone quality has been improved a little”, or “the tone quality has been improved considerably”, etc. Further, since there is a difference between individuals, the evaluation is different depending on the person, or judgment may be difficult whether the obtained result can be generalized. It is impossible to perform objective evaluation relating to whether there is actually an effect by the measures taken, or how much effect can be obtained, unless the tone quality is quantitatively expressed by physical properties.
Therefore, it is necessary to carry out subjective evaluation tests, and to execute statistical processing, to thereby quantify the tone quality.
There are psychoacoustic parameters as physical quantities for evaluating the tone quality. The representative parameters are as described below (unit is shown in the bracket). (For example, see “Seventh Lecture of Design Engineering/System Section, Design for the 21st century, Aim at innovative progress of the system!”, The Japan Society of Mechanical Engineers, Nov. 10 and 11, 1997, “Sound and Vibration and Design Color and Design (1)” Section No. 089B.)
Loudness (sone):
Size of audibility
Sharpness (acum):
Relative distribution quantity of
high-frequency component
Tonality (tu):
Tunability, relative distribution
tity of pure sound component
Roughness (asper):
Rough feeling of the sound
Flunctuation strength (vacil):
Fluctuation strength,
beat feeling.
And, other than the above, there has been proposed an instrument capable of measuring the psychoacoustic parameters, such as:
Impulsiveness (iu):
Impact property
Relative approach:
Fluctuation feeling.
All the parameters have a tendency that with an increase of the value, the discomfort increases.
Among these, only the loudness is standardized by ISO532B. With regard to other parameters, the basic idea and definition are the same, but since the program and the calculation method are different due to individual research by measuring instrument manufacturers, it is natural that the measurement value differs in each manufacturer. Further, there are original parameters, such as impulsiveness and relative app
Hirono Motohisa
Tsunoda Koichi
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Pendegrass Joan
Ricoh & Company, Ltd.
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