JP2005345923A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the harsh noise which is generated from an image forming apparatus and is sensed by a user. <P>SOLUTION: The image forming apparatus comprises a microphone 21 for detecting the magnitude of the noise on the outside of an image forming apparatus body and a person detecting means for detecting the presence or absence of surrounding persons by a plurality of filters and a pyroelectric element for detecting the IR rays transmitted through the same, and a speaker 25 for generating the addition sound to be added to the noise, and controls the addition sound generated from the speaker 25 and added to the noise, based on the detection result of the microphone 21 and the person detecting means. The harsh noise is reduced by the controlled addition sound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  An object of the present invention is to provide an image forming apparatus that reduces noise perceived by a user.

  In offices, image forming apparatuses such as printers, copiers, and facsimiles are used as OA (Office Automation) devices.

  The image forming apparatus develops an electrostatic latent image formed on a photosensitive drum (image carrier) with a main body of an image forming apparatus (hereinafter referred to as “apparatus main body” as appropriate) as a toner image, and this toner image is recorded on a recording material ( For example, the image is transferred onto paper or a transparent film and then fixed on a recording material to form an image. Further, the image forming system may be used by combining the apparatus main body and peripheral devices. For example, the copying machine may use only a copying machine main body for copying, or may be used as a copying system by arbitrarily combining peripheral devices such as an automatic document feeder, sorter, and stapler with the copying machine main body.

  By the way, in recent years, interest in noise in offices has increased. It is regarded as a problem that operating sounds such as motor driving sounds generated by operating OA equipment and operating sounds of the respective parts driven by the motors become noise.

  The OA equipment is mainly composed of members formed of various materials such as metal and plastic. In addition, the OA device includes a drive source such as a motor in order to drive each unit in the device. For this reason, during the operation of the OA device, a driving sound such as a driving sound of the motor and an operating sound of each part driven by the motor is generated.

  In an image forming apparatus such as a copying machine, resonance and vibration accompanying rotation of a motor that is a driving source, sound generated from paper and a conveyance roller during paper feeding, a rotating body such as a photosensitive drum and a developing sleeve, and a document surface There is a source of mechanical vibration, such as a scanning scanner drive mechanism.

  Recently, the sound generated by such mechanical vibration tends to increase more and more with the high-speed rotation of the drive system including the motor in order to process a large amount of copies at high speed.

  In addition, in the peripheral device, the noise accompanying the rotation of the motor of the drive source and the resonance of the device casing become noise in the automatic document feeder, and in the sorter, the noise of the paper and the transport roller and the operation sound when aligning the copy paper In the stapler, the main noise is the operation sound of pinning when stapling the paper. These noises are emitted to the outside through the paper entrance / exit and the opening for heat dissipation.

  Further, since the copying machine is compatible with various types of paper, the torque of the drive motor tends to increase, and this also causes a problem of generating noise. In a copying machine, in order to transfer a charged developer to a recording material through an image forming process such as charging, transferring, and separating, a high-voltage and high-frequency potential is applied in charging, transferring, and separating. In order to improve image quality, the number of cases using a high frequency band is increasing recently. On the other hand, there is a problem that makes people uncomfortable.

  As described above, various noises generated from the copying machine have reduced the work efficiency of the clerk working in the office room and hindered conversation.

  Copiers are generally installed in offices, laboratories, and conference areas. The background noise in the office and the laboratory is 35 to 40 dB, and the noise generated by the image forming apparatus such as a copying machine is 45 to 60 dB in the vicinity of 1 m in the vicinity. When the image forming apparatus is in operation, the noise is usually increased by 10 to 20 dB compared to the standby state.

  Therefore, the user is provided with partitions and the like in the office room and laboratory to reduce the noise in the work area.

  On the other hand, various techniques have been proposed for copying machines in order to reduce noise.

  In the image forming apparatus, the gear is changed from a spur gear to a helical gear, a special low friction coefficient material is used for the sliding portion, a sound absorbing material is mounted, a sound insulating material or a damping material is used. It has been used to reduce noise and sound.

  In Patent Document 1, Patent Document 2, and Patent Document 3, vibration is detected by a sensor attached to a rotating body or a plate-like body, and the detected signal is Fourier-transformed to obtain the vibration level of the natural vibration frequency of the rotating body. Techniques have been disclosed for checking and displaying device abnormalities and applying anti-phase vibrations to suppress vibrations.

  Patent Document 4 discloses that noise is measured and silenced.

  Patent Document 5 includes a sounding body 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 body. There has been disclosed a noise masking device that reduces discomfort due to noise by making noise inconspicuous by masking sound generated from a sounding body by control.

  Patent Document 6 proposes a technique for controlling the motor torque according to the paper type. When thick paper is selected as the image formation target paper by the operation unit, the drive current value is set to a setting value that can output a sufficient torque for feeding and transporting the thick paper, and normal paper is selected as the image formation target paper by the operation unit. An image forming apparatus having a CPU that performs control to set a driving current value to a setting value that can output a torque sufficient for feeding and transporting normal paper when selected is disclosed.

  In Patent Document 7, in order to provide an image forming apparatus in which noise is reduced and power consumption is reduced as much as possible, a plurality of cooling fans, and the cooling fan according to use conditions of the image forming apparatus are provided. A configuration is disclosed that includes a controller that controls activation, deactivation, or the state of the wind caused by the cooling fan.

  In Patent Literature 8, external noise data detected by a microphone is averaged, and the sum of the noise values in the copying operation noise data table read from the ROM is calculated, which is smaller than the noise regulation value read from the RAM. An image forming apparatus is disclosed that selects a value CPM, drives a main motor and a scanner motor in accordance with the CPM, and controls the potentials of the charging charger and transfer / separation charger to appropriate values.

  As described above, there are various conventional techniques, but noise is felt differently depending on the person.

  Patent Document 9 discloses an image forming apparatus and a sound quality improvement method that can alleviate psychological discomfort caused by sound generated from a device with respect to a person around the device based on an objective evaluation criterion. Techniques aimed at obtaining are disclosed.

  The configuration is acquired based on the loudness value A and the sharpness value B of the operating sound generated from the apparatus main body measured at a position 1 m away from the apparatus main body during exposure scanning on the image carrier by the exposure scanning apparatus. The discomfort index S of the operating sound is set within a range of S = 0.01024269 × A2 + 0.3099744 × B−2.1386517. Therefore, it is possible to evaluate the sound quality of the sound generated during operation of the apparatus based on the physical quantity.

  In addition, a technique has been proposed in which noise is silenced or reduced, and noise is controlled according to the presence or absence of a user.

  When there is a person around the copier, it is necessary to reduce the noise in order not to feel uncomfortable.

  Some conventional image reading apparatuses include a sensor (hereinafter referred to as a “human detection sensor”) that detects that a user has approached the apparatus. For example, in a copying machine, when the user does not approach the apparatus for a predetermined time or longer, the preheating mode is automatically set, and when the user approaches the apparatus when the apparatus is in the preheating mode, the preheating mode is canceled. I have control.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that is capable of detecting the document size and detecting the approach of the user without incurring complexity and cost increase of the apparatus. Instead of the mirror, a prism may be arranged, and the human path may be detected by switching the optical path obliquely above the pressure plate.

Japanese Patent Laid-Open No. 3-144663 JP-A-3-219266 Japanese Patent Laid-Open No. 4-9968 Japanese Patent Laid-Open No. 05-249983 JP-A-9-193506 JP 2001-322734 A JP-A-9-281877 JP-A-6-202402 JP 2002-131684 A JP-A-7-110534

  What was indicated by the above-mentioned patent documents 1-10 had the following faults.

  Traditionally, emphasis has been placed on reducing noise. However, depending on the user and even the same user, depending on the usage environment, it may be assumed that priority is given to productivity, high image quality, etc. rather than noise.

  For example, when a motor torque is detected and a certain value is exceeded, a system for notifying the user or stopping the control has been adopted, but depending on the user or the usage environment, the user who considers productivity rather than noise On the other hand, there is a problem of giving discomfort.

  The output value of the transfer device or developing device having a high-frequency high-voltage circuit is controlled according to the result detected by the noise detection means. However, depending on the user or the usage environment, priority is given to high image quality rather than noise. There is a drawback that the user feels uncomfortable.

  Further, when noise is generated, extra power may be consumed to suppress the noise.

  Further, with regard to detection of the presence or absence of a person, the detection means using a microphone has a drawback that noise is generated depending on the surrounding environment of the user, and the presence or absence of a person cannot be accurately detected.

  On the other hand, human detection by laser cannot accurately detect noise because it cannot detect the surrounding environment, especially the partition, the situation of stationary people, the situation of moving people, the speed of movement, etc. There is a drawback. In addition, if the user does not approach the copying machine to a certain distance, human detection cannot be performed, and the human detection possible range is somewhat narrowed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which the noise of the image forming apparatus is reduced in accordance with the presence and noise of a person around the image forming apparatus main body.

  The present invention is an image forming apparatus that forms an image on a recording material, and detects the magnitude of noise outside the image forming apparatus main body in an image forming apparatus having a noise generating source in the main body of the image forming apparatus. Noise detection means; human detection means for detecting presence / absence of a person around the image forming apparatus main body by a plurality of filters and an infrared detection member for detecting infrared rays transmitted through the plurality of filters; and an additional sound added to the noise Additional sound generating means for generating sound, and control means for controlling the additional sound generating means based on detection results of the noise detecting means and the human detecting means.

  According to the present invention, the presence or absence of a person around the image forming apparatus main body can be accurately detected by the plurality of filters and the infrared detection member. Further, since the additional sound is generated from the additional sound generating means based on the detection result to mute the noise, it is possible to perform a suitable mute according to the actual situation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but the present invention is not limited to these embodiments. In addition, what attached | subjected the same code | symbol in each drawing has the same structure or effect | action, The duplication description about these was abbreviate | omitted suitably.

<Embodiment 1>
Human hearing reacts more sensitively to sounds that change, such as sounds that occur intermittently than sounds that occur continuously. For example, when the rotational speed of a polygon mirror used in the image forming apparatus exceeds 2000 rpm, driving sound of a polygon motor (driving motor that rotates the polygon mirror at a high speed) and wind noise of the polygon mirror are remarkably generated. For this reason, unlike the conventional digital copying machine, it does not occur while waiting for the image forming operation, but the driving sound of the polygon motor and the wind noise of the polygon mirror that are generated only during the image forming operation are not generated. A person who is in the vicinity of the device (including the surroundings and wider than this, the same shall apply hereinafter) is given a stronger discomfort than when similar sounds are continuously generated.

  Here, one of the causes of “sound” heard by human ears as “noise” is the sound power level. The sound power level is represented by a value 10 times the common logarithm of the value obtained by dividing the total sound power radiated from the sound source by the 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 excessively 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, “sound” that can be heard by human ears can be heard as “noise”.

  Conventionally, sound quality, unlike physical quantities, has been evaluated by human senses that sense “sound”. For this reason, even when improvements are made to “sound” that feels like noise, the evaluation can only be expressed as “slightly improved”, “substantially improved”, etc. Evaluation could not be performed.

In contrast, in recent years, psychoacoustic parameters have been devised as physical quantities for evaluating sound quality. Typical psychoacoustic parameters are listed below.
● Sound: The volume of hearing,
Sharpness (acum): relative distribution of high frequency components, tonality (tu) articulation, content of pure tone components,
● Asper: Roughness of sound,
All psychoacoustic parameters are said to increase in discomfort to humans as the value increases.

  Among psychoacoustic parameters, loudness is standardized by ISO532B. Psychoacoustic parameters other than loudness have different calculation methods and programs to be executed based on each manufacturer, so even when measuring the sound generated from the same sound source with the same distance to the same sound source. At present, the measured values are slightly different.

  In order to objectively evaluate sound, it is necessary to capture sound as a physical quantity. By treating the sound as a physical quantity, it is possible to predict the degree of discomfort conventionally quantitatively evaluated by human subjectivity based on the physical quantity.

  In general, it has been found that the discomfort index depends on the loudness value and the sharpness value. For example, since the sharpness value particularly indicates the content of high frequency components of 4000 Hz or higher, the discomfort index can be reduced in practice by reducing the content of high frequency components of 4000 Hz or higher.

  By reducing the high frequency component, the acoustic energy is also reduced and the volume of hearing is reduced, so that the loudness value is also reduced.

  FIG. 1 schematically shows a schematic configuration of an image forming apparatus to which the present invention can be applied.

  The image forming apparatus shown in the figure is an electrophotographic image forming apparatus, and includes an electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) as an image carrier. The photosensitive drum 1 is rotationally driven at a predetermined process speed (circumferential speed) in the direction of the arrow R1 by a driving unit (not shown). Around the photosensitive drum 1, a primary charger 2 that uniformly charges the surface of the photosensitive drum 1 approximately in order along the rotation direction, and the surface of the photosensitive drum 1 after charging is exposed to form an electrostatic latent image. The exposure device 3, the developing device 4 that attaches toner to the electrostatic latent image and develops it as a toner image, the transfer device 5 that transfers the toner image onto the recording material P, and the surface of the photosensitive drum 1 after the toner image transfer is cleaned. A cleaning device 6 is provided.

  The recording material P that has been stored in the paper feed cassette 7 is conveyed to the registration roller 10 via the paper supply roller 8, the conveyance roller 9, etc., and the toner on the photosensitive drum 1 is conveyed by the registration roller 9. It was supplied so as to match the timing with the image.

  The recording material P after the transfer of the toner image is transported to the fixing device 12 by the transport belt 11, where it is heated and pressurized to fix the toner image on the surface. The recording material P after the toner image is fixed is discharged onto a paper discharge tray 15 by a paper discharge roller 14. Thereby, the image formation (copying) for one recording material P is completed. Note that an opening (discharge port) 18 for discharging the recording material P is provided in the vicinity of the discharge roller 14 in FIG.

  In the image forming apparatus described above, image information read by an image reading unit (not shown) is converted into an image signal by an image processing unit (not shown). The above-described exposure apparatus 3 includes a laser scanner (not shown) that generates laser light in accordance with the image signal and irradiates (exposes) the charged surface of the photosensitive drum 1 with the laser light. This laser scanner has a polygon mirror (not shown) and a polygon motor (not shown) that rotates the mirror at high speed. Since this polygon motor rotates at high speed, it becomes a noise generation source. The polygon mirror also becomes a wind noise (noise source). The noise will be described by taking a polygon mirror and a polygon motor as an example.

  Although not shown in particular, it has been experimentally known that the sound source of a high-frequency component of 4000 Hz or higher that is uncomfortable is the driving sound of a polygon motor or the wind noise of a polygon mirror.

  For example, a polygon motor is a rotating member such as a rotating member composed of one of a sleeve and a shaft that are fitted to each other, a fixing member composed of the other, and a dynamic pressure air bearing or a ball bearing that supports the rotation of the rotating member. And a permanent magnet attached to the rotating member, and a magnetic circuit configured by winding an electromagnetic coil around an annular iron core installed on the fixed member, thereby generating a polygonal torque. In addition, it has a magnetic circuit which has the function of the magnetic bearing which hold | maintains a rotary body to an axial direction.

  Since the polygon motor is configured as described above, noise is generated when the polygon motor is started. A description will now be given of the noise generated with the change in the rotational speed of the polygon motor in this case.

  As shown in FIG. 2, noise is generated and changed due to a change in the rotational speed of the polygon motor.

  The timing chart of FIG. 2 shows an example of noise generated in a process from when the image forming apparatus is turned on until a series of image formation is completed. The horizontal axis represents time (the rotational distance of the drive motor), and the vertical axis represents the noise level dB.

  This change in the amount of noise is substantially the same as the change in the rotational speed of the drive motor that is the main component of the drive mechanism. That is, a change in the rotation speed of a single drive motor will be described as shown in FIG. In FIG. 3, the horizontal axis is time, and the vertical axis is not the amount of noise (dB) but the rotational speed f (Hz) of the drive motor. The noise amount dB value itself (sound volume) hardly changes depending on the rotational speed of the drive motor, and the change in the frequency (tone color) of noise generated by the change in the rotational speed can be heard.

  In order to increase productivity in the image forming apparatus, the polygon motor is configured to be used at a higher rotational speed than a general drive motor. The number of rotations is 5000 rotations or more, and in some cases is 10,000 rotations or more. In this case, since a large current flows through the polygon motor at the time of start-up and the rotational speed is rapidly increased, a very large noise is generated at this time. This noise is a fluctuating sound that is linked to fluctuations in the number of rotations, and is an unpleasant sound that is very worrisome to the human ear and is a sound that gives an unpleasant feeling.

  The noise is a fluctuating sound that is linked to the rotational speed, but humans are sensitive to changes in the sound, so they notice the fluctuation.

  By analyzing the frequency spectrum of the fluctuating sound, it can be seen that it has a gentle distribution in a wide frequency band and sharp peaks protruding from the base spectrum in several frequency bands, and the sharp peaks fluctuate.

  The main component frequency with a large sound pressure level in a sharp peak is several hundred Hz to several kHz, and human hearing is sensitive to sounds in this frequency band, giving a great discomfort. It has become a sound.

  In other words, this sound is a fluctuating sound of a high frequency sound that is felt to be high, and if it is noticed and listened to that sound, it will be recognized as a sound that is very uncomfortable because it is high.

  FIG. 4 shows the result of monitoring the discomfort level felt by the user (user, operator) with respect to the noise of the image forming apparatus. Ten monitors (Mr. A to J) evaluated the noise from the low frequency band to the high frequency band generated when the image forming apparatus was stopped, operated, and turned on. As a result, the rate of discomfort (evaluation of 4 or higher) in the high frequency band is 6 out of 10 people and is quite sensitive. Furthermore, the discomfort of each frequency band differs depending on the monitor. For example, Mr. D shows discomfort in the low frequency band, but does not feel so uncomfortable in the high frequency band. Mr. A, Mr. B, etc. feel uncomfortable in the high frequency band. On the other hand, Mr. J feels uncomfortable in both the low frequency band and the high frequency band. Thus, the sensitivity to noise differs depending on the user.

  Next, human detection means for detecting a person around the apparatus main body (image forming apparatus main body) will be described.

  As a method for detecting an obstacle (object) in the surrounding environment, there are an ultrasonic method, an infrared method, a laser irradiation method, and the like. When detecting the presence or absence of a person, an infrared method is generally used. The infrared method is a method of detecting the presence (presence / absence) of a person by detecting the heat of an obstacle and detecting that the obstacle has moved. The infrared system is used for lighting and extinguishing lights and opening / closing doors in general buildings. As the human detection means by the image forming apparatus, the laser method described in the above prior art is used.

  In general, an infrared ray or a heat ray sensor using a pyroelectric element is widely used as a person detecting means in an office room or a home appliance. A pyroelectric element is a thermoelectric conversion element that once converts heat into an increase in the temperature of the element and uses a change in temperature as a variable amount of charge. If the change in charge does not occur, it cannot be extracted as a signal. It is necessary to effectively generate the heat input change.

  In addition, as a sensor using a pyroelectric element for detecting an object to be detected, there is a sensor using a polyhedral concave mirror and a pyroelectric element in the vicinity of the focal point, but the housing for housing is large.

  Further, in order to detect a stationary object to be detected, there is a method in which a motor is used to chop an infrared ray incident on the pyroelectric element with a shutter in order to make the movement of the detected object equivalently.

  In the present invention, a slit is provided in front of the detection surface of the pyroelectric element, a predetermined pattern is generated in the slit, the type of this pattern is selected according to the detection status of the detected object, and the selected pattern is moved. I did it. Thereby, the mechanical chopping process of the conventional sensor can be digitized, and a human detection sensor that can reduce the size and cost of the apparatus can be configured.

  5A and 5B are diagrams for explaining the operation of the human detection means of the present invention. FIG. 6 is a block diagram of the human detection means. The human body as the body to be detected emits infrared rays or heat rays depending on its body temperature. The human detection means includes a human detection filter (filter) 32, a pyroelectric element 31 as an infrared detection element (infrared detection member), a signal processing circuit 33, a controller B34, and the like.

  The human detection filter 32 is disposed in front of the detection surface 31 a of the pyroelectric element 31. The human detection filter 32 can display a plurality of patterns such as a vertical stripe pattern A and a diagonal stripe pattern B as shown in FIGS. 7A and 7B by the output of the controller B34. The human detection filter 32 is controlled by transmitting a signal from the controller B34 to the human detection filter drive driver 36 and the human detection filter drive motor 35, and the shape of the slit 32a changes from a vertical stripe pattern A to a diagonal stripe pattern. Switching is performed sequentially in the order of B. Note that pattern switching is appropriately referred to as filter switching.

  The signal processing circuit 33 converts the amount of charge generated in the pyroelectric element 31 into a voltage, and performs processing such as amplification, noise removal, and conversion to a signal form suitable for the controller B34. The controller B34 processes the change pattern of the detection signal processed by the signal processing circuit 33 according to a predetermined flowchart, determines the presence / absence and state of the human body as the detection target, outputs a switching signal of the human detection filter 32, and The human detection filter 32 is moved and the signal processing circuit 33 is controlled.

  Next, an outline of the operation of the system including the human detection unit shown in FIG. 6 will be described as an example when applied to an image forming apparatus. Infrared rays or heat rays emitted from the human body of the user pass through the human detection filter 32. FIG. 7 shows an example of the pattern of the slits 32 a generated in the human detection filter 32 arranged in front of the detection surface 31 a of the pyroelectric element 31. By disposing the human detection filter 32 in front of the detection surface 31a of the pyroelectric element 31, an image of the human body M in FIG. 5 is obtained as shown in FIGS. 5 (a) and 5 (b). The number of slits 32a based on the human detection filter 32 is imaged on the detection surface 31a.

  When the human detection filter 32 and the pyroelectric element 31 are in a positional relationship as shown in FIG. 5A, if the human body M is stationary, a stationary image is obtained on the detection surface 31a of the pyroelectric element 31. . If the human body M moves from the position shown in FIG. 5A to the position shown in FIG. 5B, a moving image is obtained. Furthermore, even if the human body M is stationary, if the pattern of the human detection filter 32 moves in a predetermined direction, the plurality of images also move.

  Therefore, by continuously moving the pattern of the human detection filter 32 arranged on the front surface of the detection surface 31a of the pyroelectric element 31 in a predetermined direction, the pyroelectric element 31 is in a state where the human body M is stationary. Since the charge induced in the light changes, the human body can be detected.

  The pyroelectric element 31 is sensitive to a specific infrared wavelength region and induces a charge corresponding to the amount of incident infrared rays.

  The human detection filter 32 has the above-described operation, and the controller B34 generates a pattern as illustrated in FIGS. 7A and 7B. Driven to move at speed.

  The detection sensitivity can be switched by widening the interval between the slits 32a and 32a when the amount of movement of the human body M that is the detected body is large, and narrowing the interval between the slits 32a and 32a when there is little movement. Further, although this detection sensitivity varies depending on the direction of movement, the absolute detection sensitivity is proportional to the relative change amount of the amount of infrared light incident on the detection surface 31a of the pyroelectric element 31, and therefore the pattern generated in the human detection filter 32 It is desirable to increase the aperture ratio.

  However, if the pattern aperture ratio fluctuates, the total input amount of incident infrared rays will fluctuate. Therefore, it is necessary to maintain the aperture ratio constant even when the pattern of the human detection filter 32 is switched.

  The controller B3 sends a signal to the human detection filter drive driver 36, detects the change pattern of the detection signal of the pyroelectric element 31, processes it according to a predetermined flowchart shown in FIG. 8 to be described later, and performs human detection based on the determination result. The filter 32 is instructed to be switched, and the human detection filter 32 is driven so that the pattern is moved by the human detection filter driving motor 35 at an appropriate speed.

  Each process described above is repeated, and a status detection signal is output from the controller B34 according to the determination result based on the flowchart of FIG. When it is determined that there is a person around the apparatus main body, the operation proceeds to various operations.

  Next, the above-described functions realized by the controller B34 will be described with reference to the flowchart of FIG.

  When the human detection unit is turned on and started (step S1 in FIG. 8: hereinafter abbreviated as “S1”), first, a standard pattern among a plurality of patterns formed in the human detection filter 32 is used. A pattern is formed (S2).

  When the pattern of the human detection filter 32 is the above-mentioned standard pattern, it is determined whether or not a detection signal is output from the pyroelectric element 31, and if there is a detection signal output (Yes in S3), the appearance of the detection signal is a pattern. Sampling for the first time for a predetermined time (S6).

  Next, the appearance of the detection signal after the predetermined time is sampled for the second time for the predetermined time in the same manner as the first sampling. It is determined that the first sampling and the second sampling have been completed, and if not completed, the above sampling is repeated.

  If the sampling is completed, the first and second sampling results are compared, and it is determined whether or not the difference between the patterns of the two sampling results is within a predetermined threshold range (S7). If it is equal to or greater than the threshold, it is determined that the human body is active, that is, dynamic (S8, S9), and if it is not equal to or greater than the threshold, it is determined that the human body exists but is still (S10).

  Further, the number of persons can be accurately grasped by the absolute value of the sampled signal value (S11 to S14). However, when the users are close to each other, the accuracy may be reduced.

  If the difference between the first time sampling pattern and the second time sampling pattern is outside the predetermined range, the state of the human body is not judged when the behavior change of the human body is large by performing pattern sampling again.

  In S3 described above, when the standard pattern A is generated by the human detection filter 32, if there is no detection signal output (No in S3), the human detection filter 32 is switched to another pattern B (S4). It is determined whether or not all the plural types of patterns have been switched (S5). If all the plural types of patterns have not been switched (No in S5), the presence / absence of the detection signal is determined again (S3).

  If all of the plural types of patterns are switched and there is no remaining person detection filter 32 (Yes in S5), it is determined that the pattern is absent (S16), and the process ends.

  With such a flowchart, it is possible to accurately recognize the presence or absence of a stationary person and the presence or absence of a moving person around the apparatus main body.

  The human detection means is attached to the apparatus main body and detects the presence / absence of movement of surrounding obstacles at certain time intervals. For example, the human detection means is attached to each of the front, left and right sides, and back of the apparatus main body, calculates the amount of movement of the human body M based on each detection, and predicts the human density around the apparatus main body.

  Here, the human density is the number of movements, the movement distance, and the stationary time of a person within a certain period. The density when stationary is the human stationary density, and the density when moving and entering the image forming apparatus area is the human operating density.

  When the above-described human detection filter method is used, it is possible to estimate static human density and dynamic human density. For example, the number of persons can be determined based on the absolute value of the signal value input to the controller B34 and the distribution of the input signal. Furthermore, it is possible to estimate the number of persons with dynamic density and the moving speed from the amount of change in signal value and the distribution of signals.

  On the other hand, there is also a method in which the user sets the human density without using the above-described human detection method. For example, when there is a partition around the apparatus main body, a representative user or a service person detects the human density for each time zone detected by the operation application from the operation panel 17 (see FIG. 6) of the apparatus main body, for example, You may make it input a human density for every classification of morning, morning, noon, afternoon, evening, and midnight. Note that the time period to be detected may be determined by the user. Furthermore, it becomes possible to apply to each user by finely classifying at the end of the month, the end of the year, etc.

  As the detection distance increases, the detection accuracy tends to decrease and the cost tends to increase. There are various environments in which the image forming apparatus is installed, such as a dedicated room, a side of a desk, or a corridor. Therefore, when there is no person around the apparatus main body at all times, it may be detected within a range of about 1 to 2 m on the front side of the apparatus main body on the user operation side. However, when there are many people in the vicinity, it is preferable to detect in all directions around the apparatus main body, for example, in a range of 2 m.

  Next, noise detection will be described.

  In the image forming apparatus, due to its structure, the image forming apparatus has an opening serving as a recording material inlet / outlet (opening and discharging opening) and an opening for radiating heat from the radiating fan (dissipating opening). In many cases, noise is radiated from these openings to the surroundings.

  Therefore, for example, a microphone 21 (noise detection means) is attached in the vicinity of the paper discharge outlet 18 (see FIG. 1), which is one of the openings, and the microphone 21 observes noise as a noise source signal and converts it into an electrical signal. There is a method.

  Another cause of noise is vibration of a motor or the like. The vibration of the motor or the like is observed with a vibration pickup. For example, the vibration of the main motor is observed with the vibration pickup and converted into an electric signal. Note that both the microphone 21 and the vibration pickup described above may be provided, or only one of them may be provided.

  As shown in FIG. 9, the noise source signal from the microphone 21 is subjected to appropriate signal processing in the controller A 24 which is a signal processing circuit, converted into sound waves by a speaker (additional sound generating means) 25 and output. The speaker 25 is arranged on the operation position of the user (the front surface of the apparatus main body) or the operation panel 17 with respect to the apparatus main body, and emits sound waves near the user's head.

  The signal processing circuit including the controller A24 is configured as shown in the block diagram of FIG.

  A noise source signal from the microphone 21 is A / D converted by an analog / digital (A / D) conversion circuit 23 through a noise removal filter 22. The output signal W of the A / D conversion circuit 23 is D / A converted by the digital / analog (D / A) conversion circuit 27 through the controller A 24, amplified by the power amplifier 76 through the noise removal filter 22. The sound is converted into sound waves by the speaker 25. At this time, it is necessary to design the controller A24 so that the control sounds generated from the noise generated in the apparatus main body and transmitted to the area to be silenced cancel each other.

  There are various places where there are users who use the image forming apparatus.

  For example, the area that moves when the user operates the image forming apparatus may not vary so much, or the movement area of the user may differ slightly depending on the system configuration including peripheral devices.

  In such a case, one or a plurality of microphones 21 should be installed in consideration of the user's moving area when the image forming apparatus is installed or when the power is turned on.

  The output signal of the controller A24 is determined by the output signal of the microphone 21.

  In this embodiment, as an example, a case where one microphone 21 and one mute speaker are used will be described.

  As shown in FIG. 9 described above, a noise removal filter 22, an A / D conversion circuit 23, a controller A 24, a D / A conversion circuit 27, and a power amplifier 26 are provided between the microphone 21 and the speaker 25. .

  Noise at the installation position of the microphone 21 is observed by the microphone 21, transmitted through the noise removal filter 22 and the A / D conversion circuit 23 with the transfer function A, and passes through the controller with the transfer function W.

  The output signal S of the controller A24 is transmitted through the D / A conversion circuit 27 as a transfer function, amplified by the power amplifier 26, and then converted into sound waves by the speaker 25. The sound wave is transmitted by the transfer function D to the outside world and transmitted to the silence area where the microphone 21 is installed, and is transmitted to the silence area where the microphone 21 is installed by transmitting the outside world by the transfer function D. The

  Next, the relationship between time change and frequency will be described for the additional sound generated to mute the noise.

  As described above, the types of sounds generated from the vicinity of the drive motor are generally the electromagnetic noise generated from the electromagnetic coil and the iron core when switching the current flowing to the drive motor, the wind noise caused by the friction between the rotary polygon mirror and the air, and There are three types of bearing sound due to mechanical contact between the shaft and the bearing.

  The electromagnetic sound here is a sound close to a pure sound having a sharp peak in a narrow frequency band, and the wind noise is a fluid noise having a gentle peak in a wide frequency band. Also, the bearing sound is a sound close to a pure tone with many sharp peaks depending on the shape and dimensions when using ball bearings, and is not seen with air bearings, and the frequency of these sounds is the rotation of the drive motor. It is known to be proportional to the number.

  When the band-limited noise is expressed in terms of frequency on the horizontal axis and the intensity of the noise component on the vertical axis, the noise has a frequency distribution (frequency probability distribution) as shown in FIG. In the figure, the main component frequency generated when the drive motor shown by the solid line rises fluctuates from frequency f0 to f1.

  At this time, the principal component frequency cannot be discriminated from the band-limited noise addition sound, so that fluctuations in the principal component frequency are not easily detected audibly. In addition, since the noise added here is band-limited, there is almost no increase in the volume of the noise, and so the so-called “noisy” is hardly detected audibly.

  Further, as shown in FIGS. 11A and 11B, the band-limited noise that is an additional sound has a distribution form in which the intensity of the noise component is inversely proportional to the frequency. As a result, due to the effect of “(1 / f) fluctuation”, an increase in noise is less likely to be detected audibly and can be heard comfortably.

  This is because, in general, those having a distribution form in which the fluctuation strength is inversely proportional to the fluctuation frequency, that is, those having a so-called “(1 / f) fluctuation” tend to feel comfortable to humans. However, it has been clarified in many studies, and this effect as “(1 / f) fluctuation” is utilized.

  In the present embodiment, a signal for setting the amplitude of the additional sound is sent from the operation panel 17 to the controller A24 so as to suit the preference. That is, the user sets an amplitude from the operation panel 17 to suit his / her preference, and an appropriate signal is sent from this to the controller A24.

  This signal is changed by the controller A24 and generated from the speaker 25 as an additional sound wave. As a result, the band-limited noise is added so that the sound is audibly wider than the main component frequency of the noise.

  The user adjusts the degree of noise recognition by setting the amplitude so that the user and surrounding people do not recognize the sound of the main component frequency. For this reason, the discomfort suitable for each person can be suppressed.

  FIG. 12 shows a flowchart of the mute method for optimizing the noise level according to the noise detection and human detection results described above.

  The user selects the noise level and the energy saving priority by using an operation panel installed on the front surface of the apparatus main body, for example, an operation panel having a numeric keypad and a liquid crystal screen (S21, S22, S23). When the productivity priority is not selected, that is, when the noise priority is high (when noise is to be suppressed), noise reduction is performed (S24). On the other hand, if productivity priority is selected, that is, if the noise priority is low, the presence / absence of automatic noise control is selected (S25, S26).

If there is a request for automatic noise control (S26), the process proceeds to a human detection flow (S27), and if there is no request, the process proceeds to a mute control flow (S37).
In the human detection flow (S27), first, a signal is sent from the main controller to the controller B, and the presence / absence of a person is confirmed and the values of static human density and dynamic human density are detected (S28). As a result, when the person cannot be confirmed, the absence is recognized and the noise of the image forming apparatus is not reduced (S29). If the presence of a person is confirmed, first, the static human density is counted (S30). As a result, when the density is high (S36), for example, when there are three or more people, it is determined that noise should be reduced as much as possible, and the flow proceeds to the mute control flow (S37). Conversely, if the static human density is low, the dynamic human density is then counted (S31). If the dynamic density is high, it is determined that the movement of the person is active (S32), and the mute control is not performed (S33). Further, when the dynamic human density is low, for example, about 2 people per 5 minutes, since there are few users passing through the periphery of the apparatus body (S34), the sound is temporarily muted (S35).

  FIG. 13 shows the direction of mute control by a combination of static density and dynamic density. When the dynamic human density is high and the static human density is high, it is determined that the amount of movement of the person is large, and the mute level is lowered. When the dynamic human density is high and the static human density is low, the silencing control is not performed because most people are moving around the apparatus main body. In addition, when the dynamic human density is low and the static human density is high, since most people do not move, noise reduction control is performed as much as possible. When the dynamic human density is low and the static human density is also small, no unpleasantness is given to the user. Therefore, mute control is not performed from the viewpoint of energy saving.

  Next, the mute control flow will be described. The user sets the frequency and amplitude to be muted from the operation panel 17 (S38, S39 in FIG. 12). This time, it is selected whether to remove only the high frequency that gives the most discomfort or all the frequencies (S40, S45). If it is all frequencies (S45), a signal for removing all frequencies is transmitted from the controller A (S46), and the sound source is silenced. On the other hand, if it is only a high frequency (40), first, the frequency and magnitude of noise, that is, sharpness and loudness are detected by the microphone. As a result, it is compared with a certain threshold value (S41), and if it is smaller than the threshold value, it is not changed (S42). On the other hand, if it is larger than the threshold value, the output frequency band and amplitude are determined (S43), and the sound is muted (S44). As an example, FIGS. 11A and 11B show a full-frequency silencer and a high-frequency silencer.

  According to the experimental results, according to the present embodiment, in the evaluation item “Is it suitable for the user's needs?”, 1.5 times as many people as before are judged to be effective, and “discomfort” and “can” In the “height” evaluation item, an improvement effect of about 1.21 times as compared with the conventional case was observed. From this result, it is possible to reduce discomfort to the user without unnecessarily reducing productivity by controlling the noise level according to the results of human detection and noise detection, and further according to the user's needs. .

<Embodiment 2>
In the second embodiment, as a result of human detection and noise detection, mute, polygon motor rotation speed, drive motor current, suction fan rotation, and the like are controlled in accordance with user input.

  As described in the first embodiment, the human detection means can accurately detect the static human density and the dynamic human density around the apparatus main body. Further, the muffling can be efficiently controlled by the noise detection means using the microphone.

  In the second embodiment, the number of rotations of the polygon motor, which is also a sound source of the noise, the number of rotations of the drive motor, and the like are further determined according to the above-described two control units (human detection unit and noise detection unit) and the user's request. An embodiment to be controlled will be described.

  As described above, in order to improve the productivity of the image forming apparatus, it is necessary to increase the rotation speed of the polygon motor. On the other hand, when the number of rotations is increased, a high frequency that gives discomfort is generated. In addition, it is clear that the noise increases as the rotational speed of a rotating body such as a photosensitive drum, a paper transport roller, and a developing roller is increased in order to improve productivity.

  There are other noise sources. The noise of the image reading unit and the fan will be described.

  The image reading unit of the image forming apparatus includes an illuminating unit that applies light to the original, a mirror and a lens for guiding reflected light from the original to the photosensitive drum, and the like. This type of image reading unit transmits an image of a document to a photosensitive drum by moving a carriage (moving unit) holding an illumination unit and a mirror along the document.

  An annoying noise from the image reading unit, especially the carriage, is caused by the torque of the stepping motor, the magnitude of the motor winding current, the weight of the carriage, the friction between the carriage and the rail, the wire between the carriage and the stepping motor, or This is particularly noticeable when the stepping motor falls into an overload state due to complicated influences such as belt tension, and conversely, when the driving force of the stepping motor is too large.

  Further, the image forming apparatus is provided with a heat radiating fan for releasing the heat in the apparatus main body to the outside and a suction fan for removing dust and dirt in the apparatus main body.

  Increasing the output of the heat dissipating fan to reduce the heat of the image forming apparatus increases the noise. In the image forming apparatus, paper dust and toner from the recording material, discharge products by corona band electricity, wear powder, and the like are suspended. When these foreign substances adhere to the photosensitive drum, white streaks may occur on the image. If the situation further deteriorates, the life of each component may be reduced. For this reason, it is very important to remove the suspended matter in the apparatus body by the suction fan. On the other hand, there is a case where noise from the fan makes the user uncomfortable.

  FIG. 14 shows a control block diagram of each motor by the main controller 16. In accordance with a signal from the main controller 16, the polygon motor drive circuit 45 is controlled using the controller C42 for driving the polygon motor 50 as an interface. The output value is transmitted to the polygon motor 50, and is driven at the designated rotational speed. The stepping motor A47, the stepping motor B48, and the stepping motor C49 are driven by converting a signal from the controller E41 as an interface into a driving signal by the stepping motor driving circuit 144. In the apparatus main body, for example, a fan A51 such as a suction fan of a primary charger, a fixing exhaust heat fan, and a developer suction fan, and a fan B52, a signal from a controller D43 as an interface is converted into a drive signal by a fan motor drive circuit 46. Convert and drive.

  In the flowcharts of FIGS. 15 and 16, when detecting human noise, detecting noise, or muting the sound by controlling a polygon motor, a stepping motor, a suction fan, or the like according to the user's request. Show the flow. FIGS. 15 and 16 are a series of flowcharts, but are divided for the sake of convenience.

  First, the user inputs the productivity priority from the operation panel (S51, S52, S53, S54, S55). Next, the priority of noise is input (S56). If it is desired to maintain the current noise (S57) or automatically adjust the noise (S58), human detection is started (S61). If there is no person around the apparatus main body (S63, S64), there is no discomfort due to noise, so productivity is improved. In this embodiment, as an example, the outputs of the polygon motor, drive motor, and fan are all doubled. As a result, productivity is doubled, that is, the number of copies that can be copied per unit time is doubled.

  Next, when there are people in the vicinity, the static human density and the dynamic human density are detected as in the first embodiment. The mute control is performed according to each number of people (S65, S67). In addition, when there is latitude in silence, it is possible to improve productivity and raise the silence control level. In this embodiment, first, when the static human density is low (S65) and the dynamic human density is high (S67, S68), in order to increase productivity (S69), the polygon motor output, the drive motor rotation speed, the fan All outputs are increased by a factor of 1.5 (S70). As a result, productivity is also improved by 1.5 times.

  When the dynamic human density is low (S67, S71), the noise is temporarily reduced (S72), and the mute control is started (S73). The mute level improves the productivity (S76, S77) according to the output result of the microphone and the target value, or the user's selection, or generates a specific frequency (S75), muffles the amplitude, or mute all frequencies (S81). ) Is selected. Further, considering the priority of productivity (S79, S82, S80, S83), the productivity is classified into 2 times (S84), 1.5 times (S85), and 1.2 times (S86). .

  According to the second embodiment, compared to the first embodiment, productivity and noise can be controlled according to human detection, noise detection, and user needs. In particular, for users who want to reduce noise but also increase productivity, there is a great merit that both noise and productivity can be achieved according to the density of people in the surrounding environment.

<Embodiment 3>
FIG. 17 is a block diagram of a control circuit that controls high-voltage signals for charging, developing, and transfer separation of the image forming apparatus. Signals are transmitted from the main controller 16 to a controller F61 that controls high voltage, sequence, and the like, and each high voltage substrate control circuit, that is, a charged substrate control circuit 63, a development high voltage substrate control circuit 64, and a transfer separation high voltage substrate control via an interface 62. A signal is transmitted to the circuit 65. Each circuit branches to an alternating current (AC) voltage 66, 68, 70 voltage and a direct current (DC) voltage 67, 69, 71, which are high voltage components, and outputs each voltage.

  As described above, the higher the high-pressure frequency, the greater the discomfort to the person. In particular, when the frequency is 4000 Hz or higher, sharpness increases, and a user may complain. On the other hand, the frequency in image formation has a very large meaning. In particular, when the developer is allowed to fly on a charged photosensitive drum, high image quality can be obtained by applying a high voltage having a certain frequency or higher.

  18 and 19 are flowcharts of the third embodiment. FIG. 18 and FIG. 19 are a series of flowcharts, but are divided for convenience in consideration of space.

  Human detection, noise detection, motor control, and the like are the same as those in FIGS. 15 and 16 of the second embodiment. That is, S91 to S126 in FIG. 18 and FIG. 19 correspond to S51 to S86 in FIG. 15 and FIG.

  In the third embodiment, after performing the mute control and the productivity control, the user selects an image quality mode from the operation panel 17 (S127 in FIG. 19). According to the result, a high image quality mode (S128), a normal mode (S129), and a noise response mode (S130) are provided.

  In the high image quality mode, by setting the frequency higher, the granularity of the image and the isolated dot reproducibility are remarkably improved compared to the normal mode. On the other hand, there is a drawback of outputting a high frequency. However, although not shown, it is also possible to mute a newly generated frequency band for compatibility with the mute control.

  In the noise countermeasure mode, the charging, developing, and transfer separation frequencies are lowered compared to the normal mode. As a result, although the image quality is lowered, there is an advantage that a high frequency to be worried is not output. Furthermore, although not shown in the figure, if productivity is given priority over image quality, but noise is a concern, it is possible to reduce the noise as much as possible by increasing the productivity several times and setting the mute control to the maximum output. is there.

  According to the present embodiment, as compared with the second embodiment, image quality setting and noise setting can be appropriately performed according to the user's needs by performing high-pressure control.

  The block diagram shown in FIG. 20 is a block diagram showing the relationship between the main controller 16 and the controllers A24, B34, C42, D43, E41, and F61 in the first to third embodiments.

It is a figure which shows typically the longitudinal cross section seen from the front side of the image forming apparatus which can apply this invention. It is a figure which shows the relationship between the time from the rotation start of a drive motor, and a noise. It is a figure which shows the relationship between the time from the rotation start of a drive motor, and the rotation speed of a drive motor. It is a figure which shows the discomfort degree evaluation with respect to noise by 10 monitors. (A) is a figure which shows how a human detection means detects a stationary person. (B) is a figure which shows how a person detection means detects the person of a movement state. It is a block diagram which shows the structure of a person detection means. (A) is a figure which shows the vertical stripe-like pattern A of a human detection filter. (B) is a figure which shows the diagonal stripe-like pattern B of a human detection filter. It is a flowchart which shows the flow of a person detection. It is a block diagram which shows the flow of mute. It is a figure which shows the output frequency at the time of rotation of a drive motor. (A), (b) is a figure which shows the silencing area | region of an additional sound. It is a flowchart which shows the flow which optimizes a noise level according to a noise detection and a person detection result. It is a figure which shows the directionality of the muffling control by the combination of a static human density and a dynamic human density. It is a block diagram which shows control of each motor by a main controller. It is a flowchart which shows the flow at the time of sound-extinguishing or controlling an unpleasant sound according to a person detection, noise detection, and a user's hope. FIG. 16 is a flowchart illustrating a flow when sound detection or noise control is performed according to human detection, noise detection, or user's request (continuation of FIG. 15). 3 is a block diagram of a control circuit that controls high-voltage signals for charging, developing, and transfer separation of the image forming apparatus. FIG. It is a flowchart which shows the flow at the time of sound-extinguishing or controlling an unpleasant sound according to a person detection, noise detection, and a user's hope. FIG. 19 is a flowchart illustrating a flow when sound detection or noise control is performed according to human detection, noise detection, or user's request (continuation of FIG. 18). It is a block diagram which shows the relationship between a main controller and each controller.

Explanation of symbols

1 Photosensitive drum (photoconductor)
2 Primary charger 3 Exposure device 4 Development device 5 Transfer device 6 Cleaning device 12 Fixing device 21 Microphone (noise detection means)
24 Controller A (control means)
25 Speaker (Additional sound generation means)
31 Pyroelectric element (infrared detector)
32 Person detection filter (filter)
34 Controller B (control means)
50 Polygon motor (noise source)
P Recording material

Claims (5)

An image forming apparatus that forms an image on a recording material, the image forming apparatus having a noise generation source in the image forming apparatus main body,
Noise detecting means for detecting the magnitude of noise outside the image forming apparatus main body;
Human detection means for detecting the presence or absence of a person around the image forming apparatus main body by means of a plurality of filters and an infrared detection member that detects infrared rays that pass through the plurality of filters;
An additional sound generating means for generating an additional sound to be added to the noise;
Control means for controlling the additional sound generation means based on detection results of the noise detection means and the human detection means,
An image forming apparatus. Controlling the noise source based on the detection results of the noise detection means and the human detection means;
The image forming apparatus according to claim 1. The noise generated from the noise source is an operating sound of the movable part or a wind noise of the movable part.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control means reduces noise by suppressing the operation of the movable part,
The image forming apparatus according to claim 3. The additional sound generating means irradiates the generated additional sound toward a user's head located at a predetermined position when operating the image forming apparatus;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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