JP2002128316A - Image forming device and method of improving tone quality - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax a psychological uncomfortable feeling caused by a sound generated from a device relating to a person in its periphery, based on an objective valuation standard. SOLUTION: In this image forming device, provided in a paper guide path 22 guiding paper to a prescribed route via an image forming part formed with an image on the paper so as to convey the paper by a conveying mechanism 23, in case of conveying the paper by the conveying mechanism 23, a discomfort index S of an operating sound acquired to be based on a loudness value A and sharpness value B of the operating sound generated from a device main unit measured in a position 1 m distant therefrom is set into a range obtaining S=0.01024269×A2+0.30996744×B-2.1386517.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus and a method for improving the sound quality of operation sound generated from the image forming apparatus.

[0002]

2. Description of the Related Art In an office, a large number of OAs (Official
e Automation) We handle equipment. Examples of the OA equipment include an image forming apparatus such as a copy machine and a facsimile machine.

[0003] Such OA equipment is composed of various members formed of various materials such as metal and plastic. In addition, the OA device includes a drive source such as a motor for driving each unit in the device. For this reason, O
At the time of the operation of the device A, operation sounds such as a driving sound of the motor and an operation sound of each unit driven by the motor are generated.

[0004] In recent years, there has been an increasing interest in noise in offices, and operating noises such as driving noise of motors generated by operating OA equipment and operating noises of various parts driven by motors are noise. Has been regarded as a problem.

In particular, in an image forming apparatus for forming an image on a sheet, a sliding noise is generated due to sliding of each member constituting the OA equipment and the sheet, so that the noise problem in the office is promptly dealt with. There is a need to.

Japanese Unexamined Patent Application Publication No. 9-193506 discloses a sound-emitting device that generates a masking sound for noise generated from a laser beam printer, a copying machine, and the like, and a masking sound control unit that controls the sounding device. There has been disclosed a noise masking apparatus in which a masking sound generated from a sounding body under control of a masking sound control unit at the time of occurrence makes noise less noticeable, thereby reducing discomfort caused by the noise.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No.
According to the technology disclosed in Japanese Patent Application Publication No. 193506, noise is made inconspicuous by generating a masking sound from a sounding body, so that only noise of a specific frequency is reduced from being extremely noticeable. The generated noise increases, and depending on the listener, there is a concern that the noise may be rather annoying. In addition, there is a problem that the overall sound power level increases. Furthermore, a sounding body for generating a masking sound and a control device for generating a masking sound only during the generation time of the sound to be masked are required, and an extra space is required in the layout of the machine. There is a disadvantage that the cost is greatly increased.

Furthermore, human hearing reacts more sensitively to sounds that change, such as intermittent sounds, than continuous sounds. For this reason, Japanese Unexamined Patent Application Publication No.
In the technology disclosed in Japanese Patent Publication No. 506, a masking sound is generated by overlapping a sound that changes, such as a sound that occurs intermittently, so that the sound change is emphasized. This allows
There is a concern that it may cause discomfort.

In addition, in addition to the loudness of the sound, the sound may be heard as "noise" depending on the sound quality. Conventionally, the evaluation of the sound quality largely depends on the sense of the person who perceives it, and the sound is evaluated as "noise". Even when improvements are made to sound, the evaluation can only be expressed as "slightly improved", "improved considerably", etc., and an objective evaluation of sound quality can be made. Did not.

[0010] The present invention is based on objective evaluation criteria,
An object of the present invention is to provide an image forming apparatus and a sound quality improving method that can alleviate psychological discomfort caused by a sound generated from a device to a person around the device.

[0011]

According to an aspect of the present invention, there is provided an image forming apparatus, comprising: an image forming unit for forming an image on a sheet; and a sheet for guiding the sheet to a predetermined path via the image forming unit. In an image forming apparatus including a guide path and a transport mechanism that transports the paper in the paper guide path, when the transport mechanism transports the paper in the paper guide path, at a position separated from the apparatus main body by 1 m. The discomfort index S of the operation sound obtained based on the loudness value A and the sharpness value B of the operation sound generated from the apparatus main body is S = 0.01024269 × A ² + 0.30996744 × B−2.138.
It is set within the range of 6517.

Therefore, it is possible to evaluate the sound quality of the operating sound generated when the apparatus is operating, based on the physical quantity.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the discomfort index S is S <-0.3555.
It is set within the range.

Therefore, it is possible to evaluate the sound quality of the operation sound generated when the apparatus is operated, based on the physical quantity defined in more detail.

According to a third aspect of the present invention, in the image forming apparatus of the first aspect, the discomfort index S is S <-0.6296.
It is set within the range.

Therefore, it is possible to evaluate the sound quality of the operation sound generated when the apparatus is operated based on the physical quantity defined in more detail.

According to a fourth aspect of the present invention, in the image forming apparatus of the first, second or third aspect, the paper guide path is
A sliding noise reduction device is provided that includes a guide member that regulates a guide path of the sheet and that reduces a sliding noise between the sheet conveyed in the sheet guide path and the guide member.

Here, according to human hearing, a sound generated intermittently is more unpleasant than a sound continuously generated from a sound source.

Therefore, by reducing the sliding noise between the sheet and the guide member, it is possible to more effectively reduce the psychological discomfort in practical use.

According to a fifth aspect of the present invention, in the image forming apparatus of the fourth aspect, the sliding noise reduction device contacts the paper conveyed in the paper guide path at a position different from an end surface. This is a flexible sheet-shaped member.

Therefore, with a practically simple configuration,
The operation of the invention described in claim 4 can be realized.

The invention according to claim 6 is the first or second invention.
6. The image forming apparatus according to 3, 4, or 5, wherein the loudness value A and the sharpness value B are set such that the A4 size paper whose longitudinal direction is orthogonal to the paper guide path is 230 mm / s by the transport mechanism. ~ 362m
This is the value when the paper is conveyed at a speed of m / s.

Therefore, it is possible to provide a highly versatile image forming apparatus by defining the paper size, the paper transport direction, and the transport speed which are assumed to be frequently used.

According to a seventh aspect of the present invention, there is provided a sound quality improving method, comprising: an image forming section for forming an image on a sheet; a sheet guide path for guiding the sheet to a predetermined path via the image forming section;
Generated from an image forming apparatus including a transport mechanism that transports the paper in the paper guide path, and a guide member that is provided in the paper guide path and regulates a transport path of the paper that is transported by the transport mechanism. In the method for improving the sound quality of the operation sound, by adjusting a sliding sound between the sheet and the guide member when the sheet is conveyed by the conveyance mechanism, the operation sound measured at a position 1 m away from the apparatus main body is adjusted. The discomfort index S of the operation sound obtained based on the loudness value A and the sharpness value B is expressed as S = 0.010242
69 × A ² + 0.30996744 × B−2.1386517.

Therefore, it is possible to improve the sound quality of the operation sound generated when the apparatus is operated based on the value defined by the physical quantity.

According to an eighth aspect of the present invention, in the sound quality improving method of the seventh aspect, the discomfort index S is set to S <-0.3555.
Is set within the range.

Therefore, it is possible to evaluate the sound quality of the operation sound generated when the apparatus is operated based on the physical quantity defined in more detail.

According to a ninth aspect of the present invention, in the sound quality improving method of the seventh aspect, the discomfort index S is set to S <-0.6296.
Is set within the range.

Therefore, it is possible to evaluate the sound quality of the operation sound generated during operation of the apparatus based on the physical quantity defined in more detail.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is described below.
A description will be given based on FIGS. 1 to 7. In this embodiment,
This is an example of application to a digital copying machine as an image forming apparatus.

FIG. 1 is a vertical sectional front view showing a schematic configuration of a digital copying machine according to an embodiment of the present invention. The digital copying machine 1 includes an image reading unit 2 that reads an image of a document, and an image forming unit 3 that forms an image based on image data of the document read by the image reading unit 2 by an electrophotographic method.

Although not particularly shown, the digital copying machine 1
An operation unit having a plurality of operation keys for receiving a predetermined key operation by an operator and a display unit for displaying various information is provided.

The image reading unit 2 includes a reading device 4 and an automatic document feeder (ADF) 5.

The reading device 4 has a contact glass 6 on which an original is placed. Below the contact glass 6, a first carriage 9 on which an exposure lamp 7 and a mirror 8 are mounted, and a second carriage 12 on which mirrors 10 and 11 are mounted are provided. When reading the image of the document, the first carriage 9 and the second carriage 12 are caused to travel at a speed ratio of 2: 1 by a scanner drive motor (not shown), and the reflected light from the mirror 11 is transmitted through the lens 13 to the CC.
The image on the document is optically read by forming an image on the D image sensor 14. The optically read document image is converted into an electric signal by the CCD image sensor 14,
It is subjected to predetermined image processing.

The automatic document feeder 5 feeds the sheet-like documents set on the document table 5a one by one into a contact glass 6.
It is a device that feeds automatically to the top. Set 5a on the platen
The fed document is conveyed into the automatic document feeder 5 by the feed roller 15, and when passing at a constant speed above a document reading sensor (not shown), an image on a surface facing the document reading sensor is read. . The document from which the image has been read is discharged to the discharge stacker 16.

In the image forming unit 3, a sheet feeding unit 17, a sheet feed switching unit 18 (see FIG. 2), an image forming unit 1
9, a paper guide path 22 extending to the paper discharge tray 21 via the fixing device 20 and the like is formed. In the paper guide path 22,
A plurality of transport rollers 23 are provided as a transport mechanism for transporting the paper fed from the paper feed unit 17 in a predetermined direction.

The paper feed unit 17 includes a paper feed tray 24 for holding and stacking paper, and a paper feed mechanism 25 provided on each paper feed tray 24 for separating and feeding the stacked paper.

In the image forming section 19, a photoreceptor 26 is disposed. Around the photosensitive member 26, a charger 27 for uniformly charging the surface of the photosensitive member 26, an exposure unit 28 for forming a latent image by exposing and scanning the surface of the photosensitive member 26 with a laser beam, A developing unit 29 for forming a toner image by attaching toner to the transfer unit 3 and a transfer unit 3 for transferring the toner image to a sheet fed from the sheet feeding unit 17.
0, a transport belt 32 wound around the transfer unit 30 and the rollers 31 to transport the sheet in a predetermined direction, and a cleaner (not shown) for removing toner remaining on the surface of the photoreceptor 26 are provided.

The fixing device 20 presses and heats the sheet on which the toner image has been transferred when passing through the image forming section 19. As a result, the toner image is fixed on the sheet.

When an image is formed on both sides of the sheet, the sheet on which the image is formed on one side is conveyed to the reversing unit 34 without being guided to the sheet discharge tray 21 by switching a switching claw (not shown).

The reversing unit 34 includes a reversing path 35 branching from the sheet guide path 22 on the downstream side of the image forming section 19 in the sheet conveying direction, and a reversing mechanism 36 for switching back the sheet conveyed to the reversing path 35. Have. Reversing mechanism 3
The sheet inverted in 6 is conveyed to the sheet feed switching unit 18 via the sheet re-feeding path 37.

FIG. 2 is an enlarged view showing the paper feed switching unit 18. The paper feed switching unit 18 includes a paper guide path 22 whose path is regulated by a pair of plates 38 (38a, 38b) as guide members, and a pair of plates 39 (39a, 39b).
The re-feeding path 37 whose path is regulated by the sheet feeding path 37 is provided at a junction 40 where the sheet is conveyed.
And a first switching roller 41 disposed so as to face the paper feed path 37. The first switching roller 41 is in contact with the second switching roller 42 via the paper guide path 22 and the third switching roller 43 via the re-feeding path 37.

By the way, the sheet on which the image is formed by the image forming section 19 is heated when passing through the fixing device 20, and thus has a curl to curl downward in FIG. When this sheet is conveyed to the reversing unit 34 to form an image on both sides of the sheet, a sheet having a curl habit opposite to the bending direction of the re-feed path 37 is conveyed to the re-feed path 37. Will be. As a result, the sheet conveyed to the junction 40 bends at the leading end toward the paper feed unit 17 while receiving the conveyance force in the direction of the image forming unit. Is done.

Therefore, in the present embodiment, the junction 40
In order to prevent the occurrence of jams in the
8 (38a, 38b), one end of a guide sheet 44 as a sliding noise reduction device extending in the sheet transport direction is attached to the plate 38a on the re-feeding path 37 side. The guide sheet 44 is a flexible sheet-like member, extends to the other plate 38b side so as to cross the paper guide path 22, and is bent substantially parallel to the paper guide path 22 at a bending portion 44a in the middle. ing. By providing the bent portion 44a, the guide sheet 44 comes closest to the other plate 38b at the bent portion 44a. The dimension of the guide sheet 44 in the direction orthogonal to the sheet transport direction is set to be larger than the dimension of the sheet transported in the sheet guide path 22 in the direction orthogonal to the sheet transport direction.

The shape of one end of the guide sheet 44 attached to the plate 38a may be a shape as shown in FIG. 3 (a) or a shape as shown in FIG. 3 (b). You may.

The guide sheet 44 is made of a material having a good smoothness so as not to hinder the advance of the sheet even when the surface of the guide sheet 44 and the sheet conveyed in the sheet guide path 22 come into contact with each other. Is formed. Also,
The guide sheet 44 is formed of a material having good workability such that the surface of the guide sheet 44 at the bent portion 44a is not lost even when the bent portion 44a is formed.

The flexibility of the guide sheet 44 of the present embodiment is such that the position of the leading end can be slightly displaced by the stiffness of the sheet conveyed in the sheet guide path 22. I have.

With this configuration, the sheet conveyed from the sheet feeding unit 17 to the junction 40 advances while bypassing the bent portion 44 a while contacting the guide sheet 44. At this time, since the position closest to the plate 38b is the bent portion 44a, the sheet advances while contacting the bent portion 44a of the guide sheet 44.

FIG. 4 illustrates a conventional paper feed switching unit. As shown in FIG. 4, there is a conventional digital copier in which a guide sheet 45 is provided at a junction 40. However, in general, since the guide sheet 45 as shown in FIG. 2 is formed by shearing a large-sized sheet material, burrs are generated at the sheared portion. For this reason, the occurrence of jam at the junction 40 can be suppressed by the guide sheet 45.
7 is conveyed to the junction 40 by the guide sheet 45.
When the paper advances so as to bypass the leading edge of the sheet, irregularities on the surface of the sheet and burrs on the end face of the guide sheet 45 vibrate, and the vibration generates sound.

FIG. 5 is a graph showing the result of analyzing the frequency of a sound generated from a conventional digital copying machine having the guide sheet 45 as shown in FIG. Here, the result of analyzing the frequency of the sound generated from the digital copying machine is shown for each operation mode of the paper-passing copy mode and the free-run mode. The pass-through copy mode is an operation mode in which the image forming unit 19 forms a predetermined image on the paper fed from the paper feed unit, and the free-run mode is a state in which paper is not fed from the paper feed unit. This is an operation mode in which the drive is performed in the same manner as the paper passing copy mode. According to FIG. 5, it can be seen that the generated sound is louder in the paper feed copy mode than in the free run mode.

By the way, human hearing reacts more sensitively to a sound that changes, such as an intermittent sound, than a sound that occurs continuously. For this reason, the irregularities on the surface of the sheet and the guide sheet 45 which do not occur while the image forming operation is on standby, but occur only when the sheet is being conveyed during the image forming operation.
The sound caused by the vibration of the burrs on the end face gives a greater discomfort to the people around the digital copying machine than when the sound caused by the vibration is continuously generated.

FIG. 6 is a graph showing the difference between the sound pressure levels in the paper-passing copy mode and the free-run mode based on FIG. 5 (hereinafter referred to as a difference sound pressure level). The difference between the pass-through copy mode and the free-run mode is the presence or absence of paper feed from the paper feed unit.
This can be said to be the frequency distribution of the sound generated due to the paper conveyance. According to FIG. 6, a difference sound pressure level of 3 dB or more at which a difference of more than twice occurs in acoustic energy between a band of 200 to 250 Hz and a band of 315 Hz or more. In particular, the differential sound pressure level in the band of 1250 to 1600 Hz is remarkably 7 dB or more.

The sound source of the sound at each frequency is 200 to 2
The frequency in the band of 50 Hz is caused by the sound generated by the collision between the sheet and the conveyance roller 23, and the frequency in the band of 315 Hz or more is defined by It was confirmed by experiments that it was caused by the sliding noise of the paper caused by the contact.

By the way, the "sound" heard by human ears is
One of the causes of being heard as "noise" is the sound power level. The sound power level is represented by a value which is 10 times a common logarithm of a value obtained by dividing a total sound power radiated from the sound source by a reference sound power (1 pW). That is, the sound power level is a value that can be expressed as a physical quantity. If the sound power level is too high,
Humans may feel the "sound" as noise.

However, even when the sound power level is low, “sound” may be heard as “noise”. In such a case, another factor that causes the “sound” heard by the human ear to be heard as “noise” is sound quality.

Conventionally, sound quality is different from physical quantity,
It was evaluated by the human sense of feeling. For this reason, the evaluation was "slightly improved" and "improved considerably" even when improvements were made to the "sound" that felt noise.
And so on, and no objective evaluation of sound quality could be made.

On the other hand, in recent years, psychoacoustic parameters have been devised as physical quantities for evaluating sound quality. Representative psychoacoustic parameters are listed below.・ Loudness (sone): The size of the sound ・ Sharpness (acum): The relative distribution of high frequency components ・ Tonality (tu) articulation, pure tone content ・ Roughness (asper): Sound roughness ・ Fract Tuture strength (vacil): fluctuating strength, humming ・ Impulsiveness (lu): impact

It is said that the greater the value of any of the psychoacoustic parameters, the greater the discomfort to humans.

Of the psychoacoustic parameters, the loudness is standardized by ISO532B. Psychoacoustic parameters other than loudness are different for each manufacturer because the calculation method and the program to be executed based on the calculation method are different, so even if the sound generated from the same sound source is measured by making the distance to the same sound source equal. At present, the measured values are slightly different.

In order to objectively evaluate a sound, it is necessary to take the sound as a physical quantity. By taking the sound as a physical quantity, it is possible to predict the degree of discomfort that has been quantitatively evaluated by human subjectiveness based on the physical quantity. The degree of discomfort quantitatively evaluated by human subjectivity is defined as a subjective evaluation value α,
The degree of discomfort predicted based on the physical quantity is defined as the discomfort index S.

In the present embodiment, a sound quality evaluation formula is obtained by a method described below in order to represent the correlation between the subjective evaluation value α and the discomfort index S. (1) Sound collection (2) Processing of collected sound (3) Acquisition of psychoacoustic parameters (4) Subjective evaluation (5) Multiple regression analysis

The above (1) to (5) will be described in detail below.

(1) Sampling of Sound In the above-described digital copying machine 1, the speed at which a sheet is conveyed is 362 mm / s (hereinafter referred to as speed A), 330 mm
/ S (hereinafter referred to as speed B), 305 mm / s (hereinafter referred to as speed C), 275 mm / s (hereinafter referred to as speed D),
The sound generated at each of the speeds A to E in the normal copy mode is sampled as a test sound, with five stages of 230 mm / s (hereinafter referred to as speed E). The test sound was collected in a semi-anechoic chamber, and a binaural head head was used with a dummy head HMSIII manufactured by Head Acoustics, which was set at a height of 1.2 m and a floor distance from the subject of 1 m. Recording is performed on digital audio tape (hereinafter, referred to as DAT) in the (binaural) mode.

Thus, at the time of reproducing the sound recorded in the DAT, it is possible to reproduce the same feeling as when a human hears the sound actually generated.

(2) Processing of Collected Sounds Among the test sounds collected in (1), the sounds collected at the speed A are converted from the sounds using an acoustic analyzer BAS manufactured by Head Acoustics Co., Ltd. The frequency of the portion related to the sound source on the frequency axis or the time axis is removed or the sound pressure level is adjusted, and processed into nine types of test sounds.

(3) Acquisition of Psychoacoustic Parameters Using the acoustic analyzer BAS manufactured by Head Acoustics Co., Ltd., each of the collected sounds A, B, and C collected when the paper is conveyed at speeds A, B, C, D, and E. A processing sound A1 obtained by processing a collection sound A collected when a sheet is conveyed at a speed A in C, D, and E.
Psychoacoustic parameters are obtained for each of the test sounds A to A8 (see Table 1).

(4) Subjective Evaluation Next, a subjective evaluation value for discomfort is obtained by the Scheffe pairwise comparison method. In the present embodiment, specifically, a group in which two test sounds are combined is created from the above test sounds, and which test sound is unpleasant for each group is determined by N
Evaluated by human subjects. In the evaluation, the test sound i is compared with the test sound j, and when the test sound i is evaluated as being more unpleasant than the test sound j, the evaluation of the test sound i is +1; Also, when the test sound j is evaluated to be unpleasant, the evaluation of the test sound i is set to −1, and statistical processing is performed based on the evaluation results of all the combinations to give an uncomfortable feeling to the subject's hearing. Is obtained. Subjective evaluation value α
Represents how different the reference 0 is,
The possible value of the subjective evaluation value α is −1 ≦ α ≦ 1. The subjective evaluation value α is a more unpleasant value as the numerical value is larger. Table 1
It shows the results of the experiment.

[Table 1]

(5) Multiple Regression Analysis Multiple regression analysis is performed based on each value in Table 1 to derive a mathematical expression for predicting the subjective evaluation value using psychoacoustic parameters. As a result of the multiple regression analysis, the following formula was derived. S = 0.01024269 × (loudness value) ² + 0.30996744 × (sharpness value) −2.1386517 ・ ・ ・

Since the mathematical expression is derived based on the subject's subjective evaluation value α for the generated sound, the subjective evaluation value α can be predicted in advance based on the physical quantity based on this mathematical expression. That is, the value S predicted by the formula is the discomfort index S for predicting the degree of discomfort based on the physical quantity, and the formula is obtained as a sound quality evaluation formula. If the loudness value is A and the sharpness value is B,
The sound quality evaluation formula is the following formula. S indicates an index, and there is no unit. S = 0.01024269 × A ² + 0.30996744 × B−2.1386517

From the above sound quality evaluation formula, it can be seen that the discomfort index S depends on the loudness value and the sharpness value.

FIG. 7 is a graph showing the correlation between the discomfort index S predicted by the sound quality evaluation formula and the subjective evaluation value α obtained by actual comparison evaluation. The contribution rate representing the accuracy of the sound quality evaluation formula obtained from FIG. 7 is 0.89. Thus, it can be said that the loudness value A and the sharpness value B account for 89% of the factors that make the sound uncomfortable.

Further, when various sounds were actually evaluated based on the above sound quality evaluation formula, the correlation between the evaluation result of the subject and the discomfort index S was found to be statistically 95% significant. It was found by experiment.

Since an experiment was conducted on an image forming apparatus that conveys a sheet at a speed of 230 to 362 mm / s,
The expression can be said to be effective for an image forming apparatus that conveys a sheet at a speed of 230 to 362 mm / s.

Since the sharpness value B particularly indicates the content of high frequency components of 4000 Hz or more, in practice, it is 40
The discomfort index S can be reduced by reducing the content of the high frequency component of 00 Hz or more. By reducing the high-frequency component, the acoustic energy is reduced and the size of the sound is reduced, so that the loudness value is also reduced.

By the way, as described above, it has been found by experiments that the sound source of the high frequency component sound of 4000 Hz or more that is unpleasant is the sliding sound between the paper and the guide sheet 44 at the junction 40.

In the present embodiment, the paper conveyed from the paper feed unit 17 to the junction 40 advances while bypassing the bent portion 44 a while contacting the guide sheet 44. There is no contact of the burrs at the end, no vibration due to the contact between the unevenness of the paper surface and the burrs on the end surface of the guide sheet 44, and no vibration noise.

The dimension of the guide sheet 44 in the direction perpendicular to the sheet transport direction is set to be larger than the dimension of the sheet transported in the sheet guide path 22 in the direction orthogonal to the sheet transport direction. Since the end surface of the sheet 44 in the direction perpendicular to the sheet conveyance direction of the sheet does not contact the sheet, vibration due to contact between the unevenness of the sheet surface and the burr of the end surface of the guide sheet 44 does not occur. In addition, generation of vibration noise can be suppressed.

Further, the guide sheet 44 is
By forming a sheet-like member provided with the same, it can be formed by shearing as in the conventional case, so that productivity is not reduced.

Furthermore, even when the bent portion 44a is formed, the guide sheet 44 maintains good smoothness at the bent portion 44a, so that the generation of vibration can be more effectively prevented.

[Table 2]

Table 2 shows the collected sounds A, B, C, D, and E.
Sampling sound A by subdividing the conditions more than when used for the evaluation of (4)
The correlation between the discomfort index S and the subject's subjective evaluation is shown for each of the test sounds A1 to A16 obtained by processing. The subjective evaluation is A, B,
The evaluation was made on a three-point scale designated as C. In Table 2, AA, C
As for C, all subjects who participated in the experiment performed the same evaluation.

According to Table 1, it is found that by setting the loudness value A and the sharpness value B to satisfy S <-0.3555, the discomfort is alleviated. According to this, it is understood that the discomfort is more effectively alleviated by setting the loudness value A and the sharpness value B that satisfy S <-0.6296.

In the present embodiment, the bent portion 44a is provided at the tip of the guide sheet 44 for preventing the occurrence of jam at the junction 40 due to the curl habit.
Although the noise generated at the junction 40 is prevented from being suppressed, the present invention is not limited to this.
Similarly, the noise suppressing effect can also be obtained by setting the contact position between the sheet and the part where the end has burrs due to shearing processing or the like as the bent portion 44a.

[0083]

According to the image forming apparatus of the present invention, an image forming section for forming an image on a sheet, and a sheet guide path for guiding the sheet to a predetermined path via the image forming section. And a transport mechanism for transporting the paper in the paper guide path, wherein when the transport mechanism transports the paper in the paper guide path, the paper is measured at a position 1 m away from the apparatus main body. The discomfort index S of the operation sound obtained based on the loudness value A and the sharpness value B of the operation sound generated from the apparatus main body,
By setting S = 0.01024269 × A ² + 0.30996744 × B−2.1386517, it becomes possible to evaluate the sound quality of the operation sound generated during operation of the device based on the physical quantity. Based on an objective evaluation criterion, it is possible to alleviate the psychological discomfort caused by the sound generated from the device to a person around the device.

According to the second aspect of the present invention, in the image forming apparatus according to the first aspect, the discomfort index S is set as S <−.
By setting it within the range of 0.3555, it becomes possible to evaluate the sound quality of the sound generated during operation of the device based on the physical quantity defined in more detail, so that an objective evaluation standard Based on the above, psychological discomfort caused by the sound generated from the device can be more effectively alleviated for a person around the device.

According to the third aspect of the present invention, in the image forming apparatus according to the first aspect, the discomfort index S is set to satisfy S <-.
By setting the value within the range of 0.6296, it is possible to evaluate the sound quality of the operation sound generated during operation of the device based on the physical quantity defined in more detail, so that an objective evaluation standard Based on the above, psychological discomfort caused by the sound generated from the device can be more effectively alleviated for a person around the device.

According to the invention set forth in claim 4, according to claim 1,
4. The image forming apparatus according to claim 2, further comprising a guide member that regulates a guide path of the sheet, and a sliding noise reduction device that reduces a sliding sound between the sheet conveyed in the sheet guide path and the guide member. By reducing the sliding noise between the paper and the guide member, which is perceived as a more unpleasant sound by human hearing because the sound is generated intermittently from the sound source, the Discomfort can be alleviated.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the sliding noise reduction device is provided at a position different from an end surface of the sheet conveyed in the sheet guide path. By using a flexible sheet-like member that comes into contact with the above, the effect of the invention described in claim 4 can be realized with a practically simple configuration.

According to the invention described in claim 6, according to claim 1,
6. The image forming apparatus according to 2, 3, 4, or 5, wherein the loudness value A and the sharpness value B are set such that a longitudinal direction of the A4 size paper is set to 230 mm by the transport mechanism. / S ~ 36
By providing a value when the paper is conveyed at a speed of 2 mm / s, a paper size, a paper conveyance direction and a conveyance speed which are estimated to be frequently used are defined, and a highly versatile image forming apparatus is provided. Can be.

According to the sound quality improving method of the present invention, an image forming section for forming an image on a sheet, a sheet guide path for guiding the sheet to a predetermined path via the image forming section, Generated from an image forming apparatus including a transport mechanism that transports the paper in the paper guide path, and a guide member that is provided in the paper guide path and regulates a transport path of the paper that is transported by the transport mechanism. In the method for improving the sound quality of the operation sound, by adjusting a sliding sound between the sheet and the guide member when the sheet is conveyed by the conveyance mechanism, the operation sound measured at a position 1 m away from the apparatus main body is adjusted. The discomfort index S of the operation sound obtained based on the loudness value A and the sharpness value B is defined as S = 0.
By setting the value within the range of 01024269 × A ² + 0.30996744 × B−2.1386517, it is possible to improve the sound quality of the operation sound generated during operation of the device based on the value defined by the physical quantity. Therefore, based on an objective evaluation criterion, it is possible to alleviate the psychological discomfort caused by the sound generated from the device with respect to the people around the device.

According to the eighth aspect of the present invention, in the sound quality improving method according to the seventh aspect, the discomfort index S is set to S <-.
By setting it within the range of 0.3555, it becomes possible to evaluate the sound quality of the sound generated during operation of the device based on the physical quantity defined in more detail, so that an objective evaluation standard Based on the above, psychological discomfort caused by the sound generated from the device can be more effectively alleviated for a person around the device.

According to the ninth aspect of the present invention, in the sound quality improving method of the seventh aspect, the discomfort index S is set to S <-.
By setting the value within the range of 0.6296, it is possible to evaluate the sound quality of the operation sound generated during operation of the device based on the physical quantity defined in more detail, so that an objective evaluation standard Based on the above, psychological discomfort caused by the operation sound generated from the device can be more effectively alleviated for a person around the device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a schematic configuration of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a paper feed switching unit.

FIG. 3 is a perspective view showing a guide sheet.

FIG. 4 is an enlarged view showing a conventional guide sheet.

FIG. 5 is a graph showing a result of analyzing a frequency of a sound generated from the digital copying machine.

FIG. 6 is a graph showing a difference sound pressure level of a sound between a paper passing copy mode and a free run mode.

FIG. 7 is a graph showing a correlation between a discomfort index and a subjective evaluation value.

[Explanation of symbols]

 19 Image Forming Section 22 Paper Guide Path 23 Conveying Mechanism 38 Guide Member 44 Sliding Sound Reduction Device

Continued on the front page F term (reference) 2C061 AP03 AP04 AQ06 AR03 AS02 DF03 DF12 DF17 3F101 FA01 FA03 FB02 FC07 FD04 FE08 FE19 LA02 LA05 LB03

Claims (9)

[Claims] 1. An image forming section for forming an image on a sheet, a sheet guide path for guiding the sheet to a predetermined path via the image forming section, and a conveyance for conveying the sheet in the sheet guide path And a loudness value A of an operation sound generated from the apparatus main body measured at a position 1 m away from the apparatus main body when the paper is conveyed in the paper guide path by the conveying mechanism. An image forming apparatus, wherein an unpleasant index S of the operation sound obtained based on a sharpness value B is set within a range of S = 0.01024269 × A ² + 0.30996744 × B−2.1386517. 2. The image forming apparatus according to claim 1, wherein the discomfort index S is set within a range of S <−0.3555. 3. The image forming apparatus according to claim 1, wherein the discomfort index S is set in a range where S <−0.6296. 4. The paper guide path includes a guide member that regulates a guide path of the paper, and a sliding noise that reduces a sliding noise between the paper conveyed in the paper guide path and the guide member. 4. The image forming apparatus according to claim 1, further comprising a reduction device. 5. The apparatus according to claim 1, wherein the sliding noise reduction device is a flexible sheet-shaped member that contacts the paper conveyed in the paper guide path at a position different from an end surface. The image forming apparatus according to claim 4. 6. The loudness value A and the sharpness value B are set such that the A4 size paper whose longitudinal direction is orthogonal to the paper guide path is obtained by the transport mechanism.
6. The image forming apparatus according to claim 1, wherein the value is obtained when the sheet is conveyed at a speed of 30 mm / s to 362 mm / s. 7. An image forming section for forming an image on a sheet, a sheet guide path for guiding the sheet to a predetermined path via the image forming section, and a conveyance for conveying the sheet in the sheet guide path. A method of improving the sound quality of an operation sound generated from an image forming apparatus including a mechanism, and a guide member provided in the paper guide path and regulating a transport path of the sheet transported by the transport mechanism. By adjusting the sliding noise between the paper and the guide member when the paper is conveyed, the sliding noise is obtained based on the loudness value A and the sharpness value B of the operation sound measured at a position 1 m away from the apparatus main body. The discomfort index S of the operating sound is set within a range of S = 0.01024269 × A ² + 0.30996744 × B−2.1386517. 8. The sound quality improving method according to claim 7, wherein said discomfort index S is set within a range of S <−0.3555. 9. The sound quality improving method according to claim 7, wherein said discomfort index S is set within a range of S <−0.6296.