JP2002351272A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device which can improve a noise source and relax discomfort psychologically by reducing the noise of paper feeding in an image forming device which operates at a relatively high speed. SOLUTION: The image forming device is characterized in that the discomfort index S of noise, which is obtained using the acoustic pressure level (A characteristic) and the sharpness value of a psychological acoustic parameter obtained by sound at a position 1 meter away from the end face of the image forming device, satisfies a condition, S=A×(an acoustic pressure level value)+B×(a sharpness value)-C<=-0.448, wherein 0.066<=A<=0.120, 0.342<=B<=0.709, -7.611<=C<=-4.776, the range of the acoustic pressure level value is 47.1 to 57.7 dB (A), and the range of the sharpness value is 1.80 to 3.15 (acum).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copying machine or a laser beam printer which generates noises such as a motor driving sound, an impact sound caused by the operation of clutches and solenoids, and a paper conveyance sound during operation. The improvement of discomfort sound in INDUSTRIAL APPLICABILITY The present invention is applicable to office equipment other than image forming apparatuses, printing machines, home electric appliances, and the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing interest in noise problems from the viewpoint of environmental friendliness, and office automation (hereinafter referred to as "OA") has been adopted in offices.
There are many demands for equipment to solve noise problems. for that reason,
The noise reduction of OA equipment has been advanced, and considerable noise reduction has been achieved as compared with before.

[0003] Japanese Patent Application Laid-open No.
There is one described in 193506. This relates to a noise masking device in an image forming apparatus such as a laser beam printer or a copying machine, which has a driving mechanism that is a source of noise during operation, and a sounding body that generates a masking sound for masking this noise. By providing a masking sound control means for controlling the sounding body and generating a masking sound having a frequency in a range including the main component frequency of the noise, discomfort of the noise is reduced.

The above-mentioned invention does not reduce the sound generated functionally from the original, but adds a masking sound to the generated sound. Therefore, there is a disadvantage that the noise level is increased and some listeners may feel noisy and uncomfortable. In addition, a sounding body for generating a masking sound is required, and a control device for generating a masking sound only while the sound to be masked is required. And the cost is significantly increased.

In addition to the technique described in the above publication, the following sound quality evaluation apparatus and sound quality evaluation method have been proposed. SUMMARY OF THE INVENTION The present invention relates to a sound quality evaluation device and a sound quality evaluation method, and a low-frequency random noise generated in an airflow system such as an exhaust sound from a noise composed of many sounds of an image forming apparatus. This makes it possible to evaluate only the "go sound", which is a heavy noise, and to easily deal with psychological annoyance.

[0006] Japanese Patent Application Laid-Open No. H10-253440 relates to a sound quality evaluation device and a sound quality evaluation method, in which a continuous pure tone emitted from a scanner motor or a charging device is generated from noise composed of many tones of an image forming apparatus. In this case, only the "Keen sound" which is recognized as a harsh sound is extracted and evaluated.

[0007] Japanese Patent Application Laid-Open No. 10-253442 relates to a sound quality evaluation device and a sound quality evaluation method. The noise is a high-frequency random noise caused by rubbing of paper, particularly from a noise composed of many tones of an image forming apparatus. It is possible to extract and evaluate only "sound".

[0008] Japanese Patent Application Laid-Open No. H10-267742 relates to a sound quality evaluation apparatus and a sound quality evaluation method. Only the "won-won sound" consisting of pure sounds having a peak at the point can be extracted and evaluated.

[0009] Japanese Patent Application Laid-Open No. 10-267743 relates to a sound quality evaluation device and a sound quality evaluation method. In a noise composed of sounds of many timbres of an image forming apparatus, there is no pure tone or beat, that is, a frequency waveform protrudes. If there is no such component, humans perceive the sound as a smooth sound, so the annoyance that humans perceive is collectively called `` smoothness '', it is possible to extract the smoothness of the sound and evaluate it It was done.

[0010] These series of prior arts are a sound quality evaluation device and a sound quality evaluation method.
No mention is made of a method or apparatus for improving the sound quality of an actual product.

[0011]

At present, in OA equipment,
As a method for evaluating noise, a sound power level and a sound pressure level (ISO7777) are generally used. However, since these are values of acoustic energy generated from office equipment such as copiers and printers, they may not correlate well with human subjective discomfort to noise. For example, the sound pressure level (equivalent noise level L
eq: a value obtained by averaging energy over the entire measurement time), when listening to sounds having the same value, there may be differences in discomfort depending on differences in the frequency distribution of the sounds and the presence or absence of impact sounds. In addition, even if the value of the sound pressure level is small, it may be uncomfortable when a high frequency component or a low frequency beat sound is included.

Therefore, in order to improve the office environment in the future, it is necessary not only to evaluate and reduce the sound power level and the sound pressure level of the OA equipment but also to evaluate and improve the sound quality at the same time. In order to evaluate and improve sound quality, it is necessary to quantitatively measure sound quality for grasping the current situation and to measure how much the sound quality has improved before and after the improvement. However,
Since sound quality is not a physical quantity, quantitative measurement cannot be performed. Therefore, it is difficult to set a target value.

In the case of sound quality evaluation by a human, there is no other way than to express qualitatively, such as "sound quality is slightly improved" or "significantly improved". Further, due to individual differences, evaluations differ from person to person, and it may be difficult to determine whether the obtained result is objective. Unless the sound quality is quantitatively expressed by physical characteristics, it is impossible to objectively evaluate whether the noise countermeasure or the sound quality improvement countermeasure was really effective and how much the effect was effective.

By the way, as a physical quantity for evaluating the sound quality,
There is a psychoacoustic parameter. The typical ones are as follows. Units in parentheses indicate units. For example, the Japan Society of Mechanical Engineers “7th Design Engineering and Systems Division Lecture Meeting” 21
Aiming for an innovative leap in design and systems for the 21st century! "" November 10, 1997, "Sound and Vibration and Design, Color and Design (1)", Division 089B. -Loudness (sone): the size of the hearing-Sharpness (acum): the relative distribution of high-frequency components-Tonality (tu): the content of articulatory and pure tone components-Roughness (asper): the roughness of the sound Devices that can measure psychoacoustic parameters such as "fraction strength (vacil): fluctuation intensity: beat" and "impulsiveness (iu): impact"-relative approach: fluctuation are also available. As the value of any parameter increases, discomfort increases.

Among them, only loudness is ISO532
B. Other parameters have the same basic concept and definition, but the measurement values are usually slightly different depending on the manufacturer because the programs and calculation methods differ depending on the original research of each measuring instrument manufacturer. There are also manufacturer-specific parameters. Efforts to reduce all of these psychoacoustic parameters will result in improved sound quality. However, it is laborious to take measures for all of them.

The noise generated from OA equipment such as a copying machine and a printer is composed of many timbres due to the complexity of the mechanism. For example, low-frequency heavy sound, high-frequency high-pitched sound, or sound generated by impact, etc.
It is generated while changing temporally from a plurality of sound sources such as paper and solenoids. Although humans judge these sounds comprehensively to determine whether they are unpleasant, it is considered that the determination is made by weighting which part of the sound is particularly related to discomfort. That is, there are psychoacoustic parameters that have a large effect on discomfort depending on the timbre of the noise generated by the machine, and psychoacoustic parameters that have a small effect on the discomfort.

For example, it is considered that a high-speed printer that generates a large number of impact sounds has the most unpleasant impact sound and the relation between impulsiveness and discomfort is large. Since the sound generation is small, the sound source that feels unpleasant differs depending on various conditions, such that the charging sound generated during AC charging is considered to be the most unpleasant and the relationship between tonality and discomfort is considered to be large. Therefore, the sound source for which the sound quality needs to be improved may differ between the low-speed machine and the high-speed machine. As a result, a sound source and a psychoacoustic parameter having a large improvement effect on the unpleasant sound are searched for, and the sound quality can be efficiently improved by lowering the psychoacoustic parameter value by taking measures against the sound source of the unpleasant sound and measures against the propagation path.

Therefore, by combining psychoacoustic parameters having a great improvement effect on unpleasant sounds, weighting the parameters, formulating a sound quality evaluation formula, and calculating a subjective evaluation value for the unpleasant sounds, objective evaluation of sound quality is performed. And sound quality can be improved. Furthermore, by determining the subjective evaluation value for unpleasant sound and determining the level of discomfort that disappears, and providing a device that improves sound quality so that it is less than that value, noise problems in the office can be solved. Will be done.

The present invention provides an image forming apparatus capable of relieving psychological discomfort by improving an uncomfortable sound source of an image forming apparatus that operates at a relatively high speed in order to solve the above-mentioned problem of unpleasant sound. The purpose is to provide. Another object of the present invention is to provide an image forming apparatus that can further reduce psychological discomfort. The present invention also provides
It is an object of the present invention to provide an image forming apparatus that can reduce paper conveyance noise and reduce discomfort.

[0020]

According to the first aspect of the present invention,
Using the sound pressure level (A characteristic) value obtained from the sound at a position 1 m away from the end face of the image forming apparatus and the sharpness value of the psychoacoustic parameter, the discomfort index S of the sound obtained by the following equation (a) is The condition (b) is satisfied. (A) S = A × (sound pressure level value) + B × (sharpness value) −C 0.066 ≦ A ≦ 0.120 0.342 ≦ B ≦ 0.709 −7.611 ≦ C ≦ −4.776 Range of sound pressure level value: 47.1 to 57.7 dB (A) Range of sharpness value: 1.80 to 3.15 (acu
m) (b) S ≦ −0.448

According to a second aspect of the present invention, the sound pressure level (A) obtained from the sound at a position 1 m away from the end face of the image forming apparatus.
The discomfort index S of the sound obtained by the following equation (a) using the characteristic) value and the sharpness value of the psychoacoustic parameter satisfies the following condition (b). (A) S = 0.093 × (sound pressure level value) +0.52
5 × (sharpness value) −6.194 Range of sound pressure level value: 47.1 to 57.7 dB (A) Range of sharpness value: 1.80 to 3.15 (acu
m) (b) S ≦ −0.448

The invention according to claim 3 is the invention according to claim 1 or 2
In the described invention, the obtained discomfort index S further satisfies the following condition (c). (C) S ≦ −0.672

According to a fourth aspect of the present invention, in the first, second or third aspect, a parameter obtained from a sound at a position 1 m away from an end face of the image forming apparatus satisfies the following condition. I do. Loudness is 9.00 (sone) or less Tonality is 0.08 (tu) or less Roughness is 1.65 (asper) or less Relative approach is 0.32 or less Impulsiveness is 0.48 (iu) or less

According to a fifth aspect of the present invention, in the first aspect, a loudness value, a sharpness value, a tonality value, a roughness value, a relative
The approach value and the impulsiveness value are values obtained by collecting sound generated from the image forming apparatus by an acoustic measuring device HMSIII manufactured by Head Acoustic Co., Ltd., and analyzing the sound with a sound analyzing device BAS or ArtemiS manufactured by Head Acoustic Co., Ltd. , Wherein the discomfort index S satisfies the following condition (b) or (c). (B) S ≦ −0.448 (c) S ≦ −0.672

According to a sixth aspect of the present invention, in accordance with the first aspect of the present invention, in order to satisfy the condition (b) or (c), the sound emitted from the paper-sheet conveying means is applied to the paper. And means for reducing the sliding noise of the sheet with the guide member.

According to a seventh aspect of the present invention, in the sixth aspect, the guide member for the sheet is a flexible sheet,
The flexible sheet is characterized in that the end portion of the flexible sheet that is in contact with the paper is bent.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a front view schematically showing a digital copying machine which is an example of an image forming apparatus. First, the overall configuration and operation of the image forming apparatus will be briefly described for understanding the present invention.

In FIG. 1, an image forming apparatus includes a main body 1.
And a paper feed bank unit 2 capable of two-stage paper feed. Since the main body 1 is provided with the two-stage paper feed tray, the function of the image forming apparatus can be exhibited only by the main body 1 without the paper feed bank unit 2. Further, instead of the paper feed bank unit 2, a cheap supply storage table (not shown) having the same outer shape can be attached.
The route indicated by the solid arrow in FIG.
This is a paper transport route during image formation when paper is fed from 0. 2nd tray 11 of main body 1, paper feed bank unit 2
When the paper is fed from the first tray 12 and the second tray 13, the paper transport route indicated by the broken line is used. To join.

Inside the main body 1, a charging roller 7, a writing system optical unit 4, a developing roller 8, a transfer roller 9 and the like are arranged around the photosensitive member 6 in the form of a drum. Reading system optical unit 3, registration roller pair 16, toner bottle 21, fixing device 1
7, a paper discharge roller pair 19 and the like are arranged.

The operation of the image forming apparatus will be described. First, data of a document is read by the reading system optical unit 3 and converted into a digital electric signal. This digital electric signal is subjected to image processing and sent to the writing system optical unit 4. The writing system optical unit 4 emits a light beam 5 based on the digital signal and irradiates the photosensitive member 6. The photoreceptor 6 is driven to rotate in the counterclockwise direction in FIG. 1 and the surface thereof is uniformly charged by the charging roller 7, and the original image is written on the charged surface by the writing system optical unit 4 as described above. As a result, an electrostatic latent image is formed on the photoconductor 6, and the latent image is visualized as a toner image by the developing roller 8. The toner is supplied from a toner bottle 21 to a developing unit including the developing roller 8.

On the other hand, a description will be given of an example in which the sheet is supplied from the first tray 10 of the main body 1. From the first tray 10 in which the sheets are stacked and stored, the sheet feeding roller 14
Separates only one sheet. The separated single sheet is turned tightly while being assisted by the transport assisting roller 15 and moves upward, and is abutted against the registration roller pair 16 to perform registration adjustment and timing adjustment.
Head to the imaging department.

The image formed by the toner on the photoconductor 6 is transferred to the paper when the paper passes between the photoconductor 6 and the transfer roller 9. Thereafter, the sheet is conveyed to the fixing device 17, the toner is fixed on the sheet by the fixing roller pair 18 of the fixing device 17, and is discharged to the sheet discharge tray 20 by the sheet discharge roller pair 19. The image forming speed of the image forming apparatus according to the above embodiment is, for example, about 122 mm / s, and it is possible to form 27 images per minute.

By the way, when objectively evaluating the degree of discomfort of mechanical sound, a measure for measuring discomfort is required. When evaluating the energy of sound, in the same way as measuring with a sound level meter, when evaluating discomfort, measure the physical quantity of sound and substitute the value into the sound quality evaluation formula. Will do. The sound quality evaluation formula is used to obtain a score of a sound by performing a subjective evaluation experiment (comparison of sounds) by a human, and to predict discomfort of the sound by using a plurality of psychoacoustic parameter values. A multiple regression analysis is performed on a combination of a plurality of psychoacoustic parameters for sound discomfort, and a sound quality evaluation formula is created. The parameters used in the sound quality evaluation formula are statistically 95%
It must be significant (meaningful). For the psychoacoustic parameters, for example, in the case of an analyzer manufactured by Head Acoustic, loudness, tonality, sharpness, roughness, relative approach, impulsiveness, and the like are prepared.

Here, an embodiment of the sound quality evaluation test of the unpleasant sound by the present inventors will be described. The flow of the experiment and the derivation of the sound quality evaluation formula are as follows. (1) Recording of the operation sound of the image forming apparatus by a dummy head (2) Processing of the operation sound and creation of a plurality of processing sounds (creation of test sound) (3) Psychoacoustic parameters and sound pressure level of the created test sound (4) Paired comparison experiment using test sounds ⇒ Subjective evaluation value for discomfort (that is, scored for sound) (5) Multiple regression analysis using subjective evaluation value for discomfort and psychoacoustic parameter measurement values ⇒ Derivation of sound quality evaluation formula (that is,
Using psychoacoustic parameters, make an equation to predict the score of the sound)

The above steps will be described more specifically. (1) Sampling of the operating sound of the image forming apparatus The operating sound on the front of the image forming apparatus is converted into a dummy head HMS (Head Measurement) manufactured by Head Acoustic.
ent System) III, and binaural (binaural) recording was performed on a hard disk. By recording binaural (binaural) sound and playing it back with dedicated headphones, it can be reproduced as if humans actually heard the sound of the machine. Measurement conditions • Recording environment: semi-anechoic room • Ear position of dummy head: height 1.2m, horizontal distance from the end of the device: 1m, width direction: center of the device • Recording mode: FF (free field ⇒ anechoic)・ HP filter: 22Hz

(2) Working sound processing and creation of a plurality of working sounds (preparation of test sounds) The collected working sounds were processed by the sound quality analysis software ArtemiS (Artemis) manufactured by Head Acoustic. The sound processing method is a method of attenuating or emphasizing the main sound source portion of the image forming apparatus on the frequency axis or the time axis from the recorded operation sound. The sound sources selected this time are four sound sources: paper feeding sound, metal impact sound, paper sliding sound, and main motor drive system sound. For each sound source, three levels (emphasized, original sound, attenuated) sound pressure levels were assigned, and nine combinations of different sound source levels were created based on the L9 orthogonal table.

(3) Calculation of Psychoacoustic Parameters and Sound Pressure Level of the Prepared Test Sound Psychoacoustic parameters of the operation sound of the image forming apparatus were calculated by sound quality analysis software ArtemiS manufactured by Head Acoustic.

(4) Scheffe's paired comparison method (Ura's modified method) experiment using test sounds ⇒ Calculation of subjective evaluation value for discomfort Subjects who are evaluated for test sounds are collected and paired with test sounds. They were asked to determine which one was unpleasant. "Urano's variant" of the pairwise comparison method is a pairwise comparison method as follows. Considering the order of comparison, one subject compares all combinations once. Specifically, two combinations are created from t materials, and N subjects compare all of the combinations (i, j) and (j, i). Thereby, the subjective evaluation value of each test sound was obtained and ranked. For example, when the test sound 1 and the test sound 2 were compared, calculation was made such that 1 point was obtained when the test sound 1 was unpleasant, and -1 point was obtained when the test sound 2 was unpleasant. As a result of totalizing the results and performing statistical processing, a subjective evaluation value α of each test sound was obtained. The larger the subjective evaluation value α is, the more unpleasant it is.

The results are as shown in Table 1. Sample sound 1
Is the original sound of the image forming apparatus. Table 1. Subjective evaluation value of test sound and measured value of psychoacoustic parameter

By the way, the sound pressure level and the sound power level are standardized by ISO7777, and the reference value (the value that must be observed) of the sound power level is determined by the German Blue Angel Mark, the Nordic Eco Label, the Japan Eco Mark Standard, and the like. Have been. However, in the psychoacoustic parameters, only loudness is standardized by ISO532B, but is not a reference value. Also,
For parameters other than loudness, the basic concept is the same, but since the programs and calculation methods differ depending on the original research of each measuring instrument manufacturer, the measured values usually differ slightly depending on the manufacturer. This experiment was conducted especially for the head acoustic dummy company HMSI.
II and Head Acoustic Acoustic Analyzer B
Experiments were performed using AS or ArtemiS.

(5) Multiple regression analysis based on subjective evaluation values for discomfort and measured values of psychoacoustic parameters Multiple regression analysis is performed using the subjective evaluation values and psychoacoustic parameters to derive an equation for predicting the subjective evaluation values with psychoacoustic parameters. As a result, it was found that the following equation (a) can be predicted most accurately as the subjective evaluation value α. Both the sound pressure level, the sharpness constant, and the intercept are statistically 95% significant.
Further, R ² (contribution ratio) representing the accuracy of the equation was 0.95. This means that the sound pressure level and the sharpness contribute 95% to the discomfort of the sound. The other 5% are uncomfortable due to other factors. The predicted value of the subjective evaluation value α is referred to as a discomfort index S. There is no unit for the S value. (A) S = A × (sound pressure level value) + B × (sharpness value) −C 0.066 ≦ A ≦ 0.120 0.342 ≦ B ≦ 0.709 −7.611 ≦ C ≦ −4.776

A, B, and C are multiple regression counts, and the average value in the above range is taken to represent the discomfort index S. (a) S = 0.093 × (sound pressure level value) +0.52
5.times. (Sharpness value) -6.194. As shown in Table 1, the range of the sound pressure level value is 47.
1 to 57.7 dB (A), and the range of the sharpness value is 1.
80 to 3.15 (acum).

Here, it was found that the discomfort of the image forming apparatus is represented by the sound pressure level (sound energy) and the sharpness (the content of high-frequency components, particularly, a frequency of 4 kHz or more). That is, if a sound source having a high correlation with these two parameters is taken, the discomfort is alleviated.

According to the equation (a), the parameters other than the sound pressure level and the sharpness have no relation to the discomfort or have a high correlation with the sound pressure level or the sharpness although they are related. It does not become a parameter. However, even in the case of an image forming apparatus in which psychoacoustic parameters that are not related to discomfort at present have larger values than the present situation, there is a possibility that discomfort may be affected.

Further, if the psychoacoustic parameter related to discomfort through the current sound pressure level and sharpness takes a value larger than the current value, the effects on the sound pressure level, sharpness and discomfort are reversed, and the most uncomfortable psychoacoustic May replace parameters. Therefore, from Table 1, it can be said that Expression (a) is satisfied within a range satisfying the following conditions. Loudness is 9.00 (sone) or less Tonality is 0.08 (tu) or less Roughness is 1.65 (asper) or less Relative approach is 0.32 or less Impulsiveness is 0.48 (iu) or less

Table 2 compares the sound quality of the test sounds 1 to 9 with respect to discomfort by arranging the subjective evaluation value α (actually measured value by experiment) and the discomfort index S (predicted value by formula) side by side. Table 2. Discomfort index S (predicted value by formula) and subjective evaluation value α
(Measured value by experiment)

FIG. 2 is a scatter plot in which the results of Table 2 are plotted. The subjective evaluation value α, which is the result of a human subjective evaluation experiment, and the S value have a good correlation, and by using the sound quality evaluation formula (a), it is possible to objectively evaluate discomfort in the future.

Table 3 summarizes the results of experiments on how much the discomfort index S becomes uncomfortable. Test sound 1 processed machine A for the subject 1
The participants listened to a total of 21 sounds from 17 and B to E aircraft, and evaluated their discomfort on a three-point scale. A is a good sound, C
Was evaluated as a bad sound, and B was evaluated as an intermediate sound. Among them, CC is a sound that everyone rated as C rank,
AA is a sound that everyone rated as A. According to this result, if S ≦ −0.448... Condition (b) is satisfied, the discomfort is alleviated. That is, by setting the loudness value and the sharpness value in the equation (a) so as to satisfy the condition (b), it is possible to provide an image forming apparatus in which discomfort is reduced.

Further, if the condition (c) is satisfied, it is possible to provide an image forming apparatus having a sound which hardly causes discomfort. Table 3. Absolute sound evaluation results

FIG. 3 shows an example of the result of frequency analysis (１ ／ octave band analysis) of noise of the image forming apparatus. This is a comparison between pass-through copying and free-run (a mode in which a copy operation is performed without passing a sheet). The difference in sound pressure level for each frequency bandwidth is a difference that occurs depending on whether paper is passed or not. That is, the frequency distribution of the sound caused by the paper conveyance.

According to FIG. 3, the distribution of the frequency of the noise caused by the paper conveyance is in the entire band, but especially the center frequency is 1 kHz.
It can be seen that there is much noise in the above band. Comparing the overall value, which is the sum of all frequency bands, 51.0 dB (A) at the time of paper copy and 4% at the time of free run
5.9 dB (A), which is a difference of 5.1 dB. In addition, acoustic analysis software Art manufactured by Head Acoustic Co., Ltd.
When the sharpness value was calculated using emiS, it was found that 2.4 (acum) when passing paper copy and 1.9 when free running.
(Acum). When the sound pressure level value and the sharpness value at the time of free running are substituted into the sound quality evaluation formula (a) and calculated, S = −0.922, and S ≦ −0.448... Condition (b) S ≦ − 0.672... Condition (c) is satisfied.

That is, the sound quality can be improved by reducing the noise related to the paper conveyance. Since the noise during the free-run is zero, the noise related to the paper conveyance is practically impossible to improve so far. However, the noise related to the paper conveyance is reduced so as to satisfy the conditions (b) and (c). It is possible to improve.

The following is an example for reducing noise related to paper conveyance. FIG. 4 is a cross-sectional view showing an example of a configuration from sheet feeding to registration in an image forming apparatus such as a copying machine. FIGS. 5, 6, and 7 are explanatory diagrams showing examples of the configuration around the transport auxiliary roller 15 and the mylars 24, 25, and 26 in the transport path.

First, the paper transport path will be described. In FIG. 4, the paper fed from the first tray 10 of the main body 1 by the paper feed roller 14 is transported by a transport guide member 23, a transport auxiliary roller 15, and flexible sheets (hereinafter, mylar) 24, 2.
The sheet is turned by the guides 5 and 26 and is conveyed to the registration roller pair 16 (arrow A). Also, the second tray 11
If the paper is fed from a tray below the paper, the paper is guided by
(Arrow B). Further, when a sheet is conveyed from a double-sided device, which is an external option (not shown), the sheet is guided by the mylar 26 in the direction of arrow C to the registration roller pair 16. These three paper transport paths are shown in FIGS. in this way,
Since the three paper transport paths merge, the mylars 24, 25, and 26 made of flexible sheets are frequently used as guides for smooth transport. However, when a mylar is used, the leading edge of the mylar often slides on the paper.

FIG. 8 shows a mylar 24 as a guide member.
This figure shows how the paper slides with the leading edges of the sheets 25 and 26. The surface of the paper has fiber irregularities. On the other hand, since the mylars 24, 25, and 26 made of flexible sheets are subjected to shearing, the edges are sharp and burrs may appear around them. As the unevenness of the fibers on the surface of the paper advances, the burrs on the edges of the mylar and the paper vibrate, generating loud noises and noise. In particular, paper has a large area so that sound is easily emitted.

Therefore, in the embodiment of the present invention, the following vibration is prevented from occurring. FIG. 9 shows an example in which a mylar having a thickness of half or less is used, and a folded mylar is used as a paper guide. The tip of the mylar 27 is rounded not by an edge but by folding. The surface of the mylar is extremely smooth, and its smoothness is not lost even at the folded part. Therefore, even if the irregularities of the fibers on the surface of the paper slide with the tip of the mylar 27, no noise is generated.

If there is no route indicated by arrow C, that is, a transfer route from the double-sided device which is an external option,
The mylar 26 does not need to be folded back, but may simply be bent toward the outside of the sheet transport path at an appropriate angle at an appropriate site near the end, as in the mylar 28 shown in FIG. Mylar 28 with a smooth curved surface
No noise is generated because the bent portion of the sheet slides on the paper surface.

FIG. 11 shows a view of the Mylar 2 as in the example of FIG.
8 is obtained by bending an appropriate part near the leading end toward the outside of the paper transport path at an appropriate angle, and when the paper is fed from the second tray 11 or a lower tray as shown by arrow B. , Mylar 28 and paper. Also in this case, the paper is in sliding contact with the bent portion of the mylar 28, and noise caused by sliding of the edge of the edge of the mylar 28 against the paper is not generated.

In the above, the sliding between the front end of the mylar and the surface of the paper has been described in the above embodiments. Dynamic noise can be reduced.

[0060]

According to the first and second aspects of the present invention,
When the discomfort index S of the sound obtained by the expression (a) satisfies the condition (b), the discomfort of the noise emitted from the image forming apparatus can be reduced. Claims 3 and 4
According to the invention described in the fifth aspect, by satisfying the conditions described in the respective claims, the discomfort of the noise generated from the image forming apparatus can be more effectively reduced.

According to the sixth or seventh aspect of the present invention, the noise that causes discomfort can be reduced by reducing the sliding noise between the paper and the paper guide member.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an example of an image forming apparatus to which the present invention can be applied.

FIG. 2 is a discomfort index S (predicted value by an equation) and a subjective evaluation value α.
6 is a graph showing the relationship of (measured value by experiment).

FIG. 3 is a graph showing a comparison between noise frequency distributions at the time of copying and at the time of free running.

FIG. 4 is a front view showing a main part of an embodiment of the image forming apparatus with improved sound quality according to the present invention.

FIG. 5 is a front view showing a configuration example from paper feeding to registration in the image forming apparatus.

FIG. 6 is a front view showing a configuration example from the sheet feeding to the registration in the image forming apparatus, and showing a case where the sheet transport path is different.

FIG. 7 is a front view showing a configuration example from paper feeding to registration in the image forming apparatus, showing a case where the paper transport path is further different.

FIG. 8 is a simplified front view showing an example of a case where a paper transport path is a noise generation source.

FIG. 9 is a simplified front view showing an example of a sheet transport path which has been eliminated as a noise source applicable to the image forming apparatus of the present invention.

FIG. 10 is a simplified front view showing another example of a sheet conveyance path which has been eliminated as a noise source applicable to the image forming apparatus of the present invention.

FIG. 11 is a front view illustrating an example of a sheet conveyance path applicable to the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2 Paper feed bank unit 4 Writing system optical unit 6 Photoconductor 8 Developing roller 9 Transfer roller 24 Mylar as a guide member 25 Mylar as a guide member 26 Mylar as a guide member 27 Mylar as a guide member 28 Guide Mylar as a component

Claims (7)

[Claims] An unpleasant sound obtained by the following equation (a) using a sound pressure level (A characteristic) value obtained from a sound at a position 1 m away from an end face of the image forming apparatus and a sharpness value of a psychoacoustic parameter. An image forming apparatus, wherein the index S satisfies the following condition (b). (A) S = A × (sound pressure level value) + B × (sharpness value) −C 0.066 ≦ A ≦ 0.120 0.342 ≦ B ≦ 0.709 −7.611 ≦ C ≦ −4.776 Range of sound pressure level value: 47.1 to 57.7 dB (A) Range of sharpness value: 1.80 to 3.15 (acu
m) (b) S ≦ −0.448 2. The sound discomfort obtained by the following equation (a) using a sound pressure level (A characteristic) value obtained from a sound at a position 1 m away from the end face of the image forming apparatus and a sharpness value of a psychoacoustic parameter. An image forming apparatus, wherein the index S satisfies the following condition (b). (A) S = 0.093 × (sound pressure level value) +0.52
5 × (sharpness value) −6.194 Range of sound pressure level value: 47.1 to 57.7 dB (A) Range of sharpness value: 1.80 to 3.15 (acu
m) (b) S ≦ −0.448 3. The image forming apparatus according to claim 1, wherein the obtained discomfort index S further satisfies the following condition (c). (C) S ≦ −0.672 4. The image forming apparatus according to claim 1, wherein a parameter obtained from a sound at a position 1 m away from an end face of the image forming apparatus satisfies the following condition. Loudness is 9.00 (sone) or less Tonality is 0.08 (tu) or less Roughness is 1.65 (asper) or less Relative approach is 0.32 or less Impulsiveness is 0.48 (iu) or less 5. An acoustic measuring device HMS manufactured by Head Acoustic Co., Ltd. for the loudness value, sharpness value, tonality value, roughness value, relative approach value, and impulseness value.
III, which is a value obtained by analyzing with an acoustic analyzer BAS or ArtemiS manufactured by Head Acoustic Corporation, wherein the discomfort index S satisfies the following condition (b) or (c). The image forming apparatus according to any one of 1 to 4. (B) S ≦ −0.448 (c) S ≦ −0.672 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to satisfy a condition (b) or (c) with respect to a sound emitted from a paper sheet conveying unit.
An image forming apparatus comprising means for reducing sliding noise between a sheet and a guide member for the sheet. 7. The image forming apparatus according to claim 6, wherein the guide member of the sheet is a flexible sheet, and a contact portion of the end of the flexible sheet with the sheet is bent. .