JP2021001962A - Heater drive device, compound machine and heater drive method - Google Patents

Abstract

To provide a heater drive device capable of appropriately selecting a drive method according to the type of a light source sharing a compound machine and a power supply.SOLUTION: A heater drive device comprises: light source determination means of determining the type of a light source that shares a compound machine and an AC power supply; drive method selection means of selecting a method for driving a heater used in a heating and fixing device of the compound machine based on the type of the light source determined by the light source determination means; and heater drive means of driving the heater by the method selected by the drive method selection means.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heater drive device, a multifunction device, and a heater drive method, in particular, a heater drive device for driving a fixing heater included in a fixing portion provided in the multifunction device, a multifunction device including such a fixing heater, and the like. The present invention relates to a heater driving method for driving such a fixing heater.

Multifunction devices including electrophotographic image forming devices are often installed in offices of companies and the like, and share an AC power supply with a lighting device in the office room.

By the way, the electrophotographic image forming apparatus includes a fixing portion for fixing a toner image transferred to a recording medium such as paper to the recording medium. In the fixing portion, when the recording medium passes through the pinch portion composed of the heating roller and the pressure roller which are arranged facing each other and rotate in opposite directions, the toner image transferred to the recording medium is transferred to the fixing portion. It is fixed to the recording medium by heat and pressure.

Japanese Unexamined Patent Publication No. 63-48349

Here, the heating roller needs to be heated to a predetermined temperature, and a heating heater (for example, a heating heater lamp) is used for that purpose.

In order to maintain the heating roller at a predetermined temperature, the heating heater is turned on / off by a predetermined method.

Since the heater consumes a certain amount of electric power, the power supply voltage drops to some extent when the heater is on. Therefore, by controlling the on / off of the heater, the power supply voltage of the lighting device that shares the power supply with the multifunction device also fluctuates, and the illuminance of the lighting is linked to the on / off of the heater. Will fluctuate.

Conventionally, fluorescent lamps are often used as lighting, and a heater on / off control method has been adopted in accordance with this. That is, the light of the fluorescent lamp has flicker at the frequency of the AC power supply (50 Hz or 60 Hz), but when the heater is turned on / off by the AC phase control method, the fluorescent lamp by this on / off control Even if fluctuations in light intensity are superimposed, humans do not know much, so the heater was turned on / off by an AC phase control method.

However, lighting devices that use LEDs as the light source are gradually becoming widespread, but when this LED lighting device is used, if the heater is still turned on / off by the AC phase control method, the drive voltage will fluctuate. Since the light source intensity of the LED fluctuates with high followability in time, the intensity of the LED light fluctuates in synchronization with the on / off of the heater in the AC phase control method. Such fluctuations in the intensity of the LED light may be unpleasant for humans.

Therefore, in accordance with the case where a lighting device that uses LEDs as a light source is used, if on / off control is performed so that the heater is turned on / off in a long cycle without using the AC phase control method, a fluorescent lamp is used as the light source. When the lighting device is used, the intensity of the light of the fluorescent lamp according to the cycle will fluctuate in the cycle. Such fluctuations in the light intensity of fluorescent lamps can also be unpleasant for humans.

Therefore, the present invention provides a heater drive device capable of appropriately selecting a drive method according to the type of light source that shares a power source with the multifunction device, a multifunction device provided with the heater drive system, and such a heater drive method. With the goal.

According to the present invention
A light source discriminating means for discriminating the type of light source that shares an AC power supply with the multifunction device,
A drive method selection means for selecting a method for driving a heater used in the heating and fixing device of the multifunction device based on the type of the light source determined by the light source determination means.
A heater driving means for driving the heater by the method selected by the driving method selecting means,
A heater drive device comprising the above is provided.

Further, according to the present invention, there is provided a multifunction device including the above-mentioned heater driving device.

Further, according to the present invention
A light source determination step that determines the type of light source that shares AC power with the multifunction device,
A drive method selection step for selecting a method for driving a heater used in the heating and fixing device of the multifunction device based on the type of the light source determined by the light source determination step.
A heater drive hand step that drives the heater by the method selected by the drive method selection step,
A heater driving method is provided.

The drive system can be appropriately selected according to the type of light source that shares the power supply with the multifunction device.

It is a functional block diagram which shows the structure including the multifunction device by 1st Embodiment of this invention. It is a figure which shows the type of the lighting apparatus and a light source shown in FIG. It is a figure which shows the frequency spectrum of the wavelength of the LED light source. It is a figure which shows the frequency spectrum of the wavelength of the fluorescent lamp light source. It is a circuit diagram of a heater drive circuit by an AC phase control system. (A) shows the waveform of the drive signal of the heater drive circuit by the AC phase control system according to the embodiment of the present invention, and (b) is the heater drive circuit by the DC on / off control system according to the embodiment of the present invention. The waveform of is shown. It is a circuit diagram of the heater drive circuit by the DC on / off control system by embodiment of this invention. (A) shows the waveform of the drive signal of the heater drive circuit by the AC phase control method according to the embodiment of the present invention, and (b) varies depending on the heater drive circuit by the AC phase control method according to the embodiment of the present invention. The waveform of the AC power supply is shown. (A) shows the waveform of the drive signal of the heater drive circuit by the DC on / off control method according to the embodiment of the present invention, and (b) shows the heater by the DC on / off control method according to the embodiment of the present invention. The waveform of the AC power supply fluctuating by the drive circuit is shown, and (c) shows the LED drive power supply acquired by rectifying the AC power supply fluctuating by the heater drive circuit by the DC on / off control method according to the embodiment of the present invention. The waveform is shown. It is a figure which shows the frequency spectrum of the drive signal by the AC phase control system by embodiment of this invention. It is a figure which shows the frequency spectrum of the drive signal by the DC on / off control system by embodiment of this invention. It is a functional block diagram which shows the structure including the multifunction device by the 2nd Embodiment of this invention. It is a functional block diagram which shows the structure including the multifunction device by the 3rd Embodiment of this invention. It is a conceptual sectional view of the multifunction device according to the 7th Embodiment of this invention. It is a functional block diagram of the multifunction device according to the 7th Embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 shows a configuration including a multifunction device according to the first embodiment of the present invention.

Referring to FIG. 1, the lighting device 403 and the multifunction device 800 receive an AC power supply from a common power supply 401. Here, the lighting device 403 is, for example, as shown in FIG. 2, a fluorescent lamp lighting device 403A having a fluorescent lamp 405A as a light source 405 or an LED lighting device 403B having an LED 405B as a light source, but the present invention is not limited to this. In addition, for example, an incandescent lamp lighting device having an incandescent lamp as a light source may be used.

The multifunction device 800 includes an image forming device 30, a document reading device 820, a light source discriminating unit 303, a drive method selection unit 305, a heater drive unit A 307A, a heater drive unit B 307B, and a switch 309.

The image forming apparatus 30 includes a fixing portion 34. Other components of the image forming apparatus 30 are not shown in FIG. These will be described later.

As described above, the fixing portion 34 includes a heating roller 34a and a pressure roller 34b that are arranged so as to face each other and rotate in opposite directions, and also includes a fixing heater 311. The fixing heater 311 heats the heating roller 34a.

The document reading device 820 includes an RGB image sensor 301 for reading an image from the scanned document. In the present embodiment, the image sensor 301 is used as a light receiving element for receiving the light from the light source 405. The document reading device 820 includes a document automatic feeding unit 824 and a reading device main body 820, as will be described later. Normally, the automatic document feeding unit 824 covers the glass document table 826 of the reading device main body 822, but by opening this to the rear opening, for example, the document is not placed on the document table 826. The light from the light source 405 passes through the platen 826 and reaches the RGB image sensor 301.

The light source discrimination unit 303 determines whether or not the light source is an LED based on the ratio of the RGB components of the light received by the image sensor 301.

FIG. 3 shows the wavelength distribution of the LED light source, and FIG. 4 shows the wavelength distribution of the fluorescent light source. In this embodiment, the light in the wavelength range of 450-495 nm is the light corresponding to B (blue), the light in the range of 495-570 nm is the light corresponding to G (green), and the light in the range of 620-750 nm is R ( Treat as light corresponding to red).

In the case of LED, as shown in FIG. 3, the peak value of the energy in the wavelength range of 450-495 nm corresponding to B (blue) and the peak value of the energy in the range of 495-570 nm corresponding to G (green) are set. By comparison, the former is larger. Further, the peak value of the energy in the range of 620-750 nm corresponding to R (red) is smaller than these peak values.

In the case of a fluorescent lamp, as shown in FIG. 4, the peak of energy in the wavelength range of 450-495 nm corresponding to B (blue) and the energy in the range of 495-570 nm corresponding to G (green). Comparing the peak values, the former is smaller. Further, the peak value of the energy in the range of 620-750 nm corresponding to R (red) is larger than the peak value of the energy in the range of 450-495 nm corresponding to B (blue).

From these features, it is possible to determine whether the light source is an LED or a fluorescent lamp. For example, it can be discriminated only by comparing the peak value of the energy in the wavelength range of 450-495 nm corresponding to B (blue) and the peak value of the energy in the range of 495-570 nm corresponding to G (green). Further, it may be added as a condition for determining that the light source is an LED that the peak value of the energy in the range of 620 to 750 nm corresponding to R (red) is smaller than these peak values. Further, the color intensity distribution may be stored for each type of light source, and at the same time, the actual type of light source may be estimated by comparing with the measured value.

The heater drive unit A 307A is a heater drive unit according to the method when the light source is a fluorescent lamp. On the other hand, the heater drive unit B 307B is a heater drive unit according to the method when the light source is an LED.

The drive method selection unit 305 selects the heater drive unit A 307A or the heater drive unit B 307B as the heater drive unit using the discrimination result by the light source discrimination unit 303, and switches so that it drives the fixing heater 311. Switch 309.

The heater drive unit A 307A is a heater drive circuit based on an AC phase control method. FIG. 5 shows the circuit. FIG. 6A shows the waveform of the drive signal by the heater drive unit A 307A.

Referring to FIG. 5, the heater drive unit A 307A, which is a heater drive circuit based on the AC phase control method, includes a control circuit 501, a light emitting diode D2, thyristors T3, T4, and a current detector CT. The control circuit 501 controls the on / off of the light emitting diode D2 so that the temperature of the fixing heater HTR becomes the set temperature based on the voltage of the AC power supply AC and the current detected by the current detector CT. The on / off period of the thyristors T3 and T4 is controlled via the above.

The heater drive unit B 307B is a heater drive circuit based on a DC power supply on / off control method. FIG. 7 shows the circuit. FIG. 6B shows the waveform of the drive signal by the heater drive unit B 307B.

Referring to FIG. 7, the heater drive unit B 307B, which is a heater drive circuit based on the DC power on / off control method, includes a rectifier circuit 511, a switch 513, and a switch control unit 515. The rectifier circuit 511 converts the AC power supply AC into a DC power supply. The switch control unit 515 controls the switch 513 on / off so that the temperature of the fixing heater HTR becomes the set temperature at the set temperature based on the current detected by the current detector CT.

In both the heater drive unit A 307A and the heater drive unit B 307B, the temperature of the fixing heater HTR can be estimated based on the current detected by the current detector CT, but the fixing heater can be estimated by the temperature measuring means. The temperature of the HTR may be measured.

Next, the reason why both the heater drive unit A 307A and the heater drive unit B 307B are provided will be described.

In the AC phase control by the heater drive unit A 307A, the heater is driven by the signal as shown in FIG. 6A or FIG. 8A. In this case, the AC power supply is used. It fluctuates as shown in FIG. 8B under the influence of AC phase control. That is, the amplitude in the ON period is smaller than the amplitude in the OFF period. Therefore, the fluorescent lamp 405A attached to the conventional fluorescent lamp illuminating device 403A is driven by an AC signal having a waveform as shown in FIG. 8B. Then, the flicker synchronized with the AC power supply of the fluorescent lamp 405A is modulated by the influence of the modulation signal in the AC phase control. However, such modulation is not offensive to humans.

On the other hand, the LED 405B attached to the simple LED lighting device 403B is driven on / off by a DC power supply obtained from an AC power supply by a simple rectification method such as half-wave rectification or full-wave rectification. There is.

When the AC power supply fluctuates as shown in FIG. 8B under the influence of the AC phase control, the DC power supply is obtained from such an AC power supply. Then, the frequency fluctuation of the modulated signal in the AC phase control will occur in the DC power supply. The light intensity of the LED driven by the DC power source modulated in this way also fluctuates. This can be offensive to humans.

However, if the frequency of fluctuations in the intensity of LED light is low, such fluctuations will not be very unpleasant for humans. Therefore, for example, the modulation frequency is set to 0. It may be sufficient to just drop it to a few hertz to a few hertz. However, the band of the AC phase-modulated AC signal is only distributed in the vicinity of 50 Hz or 60 Hz, which is the frequency at the time of no modulation. Therefore, simply lowering the frequency of the modulated signal while using the AC phase control method remains unpleasant for humans.

Next, in the DC on / off control by the heater drive unit B 307B, the heater is driven by the signal as shown in FIG. 6 (b) or FIG. 9 (a). In this case, the fixing heater HTR is driven. The AC power supply fluctuates as shown in FIG. 9B under the influence of DC on / off control. That is, the amplitude of the envelope of the AC power supply fluctuates according to the DC on / off control, but the AC continues continuously. As described above, the simple LED lighting device 403B rectifies such alternating current to generate a DC power supply whose voltage fluctuates as shown in FIG. 9C, thereby driving the LED 405B. At this time, the intensity of the LED light emitted from the LED 405B fluctuates as shown in FIG. 9 (c). Therefore, by lowering the fundamental frequency of the DC on / off control, it becomes possible to lower the frequency of fluctuations in the intensity of the LED light, and at this time, there is no discomfort for humans. For example, if the main fraction of on / off is set to 0.06 hertz, the fluctuation cycle of the intensity of the LED light can be set to about 15 seconds, and at this time, humans are not uncomfortable.

FIG. 10 shows the frequency spectrum distribution of the AC power supply affected by the fixing heater drive signal when the heater drive unit A 307A is used. The power supply frequency spectrum has a frequency band spread W due to phase modulation centered on 50 Hz or 60 Hz on both the high frequency side and the low frequency side. This corresponds to the waveform shown in FIG. 8 (b). Since a light source (fluorescent lamp) other than an LED is used without converting such a power source into direct current, the frequency spectrum of the power source for the light source is also the same.

FIG. 11A shows the frequency spectrum distribution of the AC power supply affected by the fixing heater drive signal when the heater drive unit B 307B is used. This corresponds to the waveform shown in FIG. 9B.

FIG. 11 (c) is a DC waveform obtained by circular bevel detection of the AC power supply shown in FIG. 9 (b). FIG. 11B shows the frequency spectrum distribution of this.

It is good that the drive system is always selected according to the type of lighting, but the type of light source can be measured only when the automatic document feeding unit 824 is opened. Therefore, for example, the measurement and the switching of the drive method of the fixing heater may be performed each time the document automatic feeding unit 824 is opened, and the document automatic feeding unit 824 may be maintained until the next opening. Considering the case where the automatic document feeding unit 824 is not opened for a long time, for example, the light source for each time zone may be learned over several weeks, and the drive system may be switched using the learning result. Further, a window may be provided in the main body, and the window may be opened when necessary so that light is incident on the image sensor 301 from the outside. Further, a mirror may be provided between the window and the image sensor 301 so that the arrangement of the image sensor 301 can be maintained.

When the R component is not relatively weaker than the B and G components, the external light may be determined to be natural light and the heater drive unit A 307A may be used.

[Second Embodiment]
FIG. 12 shows a configuration including a multifunction device according to the second embodiment of the present invention.

In the first embodiment, the image sensor 301 of the document reading device 820 is used, but in the second embodiment, the image sensor 323 of the internal dedicated imaging device 321 is used instead. A window may be provided in the housing of the multifunction device 800 so that the image sensor 323 of the internal dedicated image pickup device 321 can constantly measure light, and light may be incident on the internal dedicated image pickup device 321 from here.

[Third Embodiment]
FIG. 13 shows a configuration including a multifunction device according to a third embodiment of the present invention.

In the first embodiment, the image sensor 301 of the document reading device 820 is used, but in the third embodiment, the image sensor 327 of the external dedicated image pickup device 325 is used instead. Thereby, for example, it is possible to cope with the case where the multifunction device 800 is installed in a place where the light of the illumination is hard to reach.

[Fourth Embodiment]
In the fourth embodiment, a sensor for measuring the amount of light from the light source is used.

Then, for example, as a result of determining the wavelength spectrum for each color according to the first embodiment, even if it is determined that the light source is a light source other than the LED and the heater is driven by the AC phase control method, the fourth If a flicker of a predetermined amount or more is detected by the light amount sensor according to the embodiment, the light source may actually be an LED, so the drive method is switched to a long-cycle on / off control method of the DC power supply.

On the contrary, for example, as a result of determining the wavelength spectrum for each color according to the first embodiment, it is determined that the light source is an LED light source, and the DC power supply is driven by a long-period on / off control method. However, if a flicker of a predetermined amount or more is detected by the light amount sensor according to the fourth embodiment, the light source may actually be other than the LED, so the drive method is switched to the AC phase control method.

[Fifth Embodiment]
When it can be determined from the wavelength spectrum that the LED and the light source other than the LED are mixed, for example, the heater is driven by a driving method suitable for the light source having the higher illuminance.

Even when it can be determined from the wavelength spectrum that sunlight is also mixed, the drive method of the heater may be controlled in the same manner as when sunlight is not mixed.

[Sixth Embodiment]
When the light source is an incandescent lamp, it may be treated in the same manner as an LED if it has good followability to power fluctuations, or it may be treated in the same way as a fluorescent lamp if it has poor followability to power fluctuations. Good.

[7th Embodiment]
A seventh embodiment relates to a multifunction device 800 including a document reader according to the first to sixth embodiments. 14 and 15 show the configuration of the multifunction device 800 and the like.

As shown in FIGS. 14 and 15, the multifunction device 800 includes a document reading device 820 that reads an image of a document, a multifunction device main body (image forming unit main body) 830 that forms an image on a sheet, and a document reading device 820 and a composite. It includes an operation panel unit 843 for operating the machine main body 830, and an arithmetic processing unit 841 that controls the document reading device 820 and the multifunction device main body 830 based on the operation by the operation panel unit 843.

In addition to using the document reading device 820 as a single unit for image reading and using the multifunction device main body 830 as a single unit for image formation, these can also be linked to copy an image. Further, the multifunction device 800 may include a storage device and a facsimile machine (not shown). The storage device can store the image read by the document reading device 820 and the image received by the facsimile machine. The facsimile machine can transmit the image read by the document reading device 820 and the image stored in the storage device, and can receive the image from the outside. Further, the multifunction device 800 may include an interface for connecting to a personal computer via a network. The personal computer connected to the multifunction device 800 can use the function of the multifunction device for the data that can be managed by the personal computer.

The document reading device 820 includes a document automatic feeding unit SPF (Single Pass Feeder) 824 for automatically feeding the document, and a scanning device main body 822 for reading the image of the document. In addition to the components shown in FIG. 15, the document reading device 820 also includes components not shown in FIG. 15 but shown in FIG. Further, as shown in FIG. 14, the reading device main body 822 is provided with a document base 826.

The multifunction device main body 830 is formed on a sheet feeding unit 10 for feeding a sheet, a manual feeding unit 20 capable of manually feeding a sheet, and a sheet fed by the sheet feeding unit 10 or the manual feeding unit 20. An image forming unit 30 for forming an image is provided.

The sheet feeding unit 10 includes a sheet loading unit 11 for loading sheets and a separate feeding unit 12 for separately feeding the sheets loaded on the sheet loading unit 11 one by one. The seat loading portion 11 includes a middle plate 14 that rotates about a rotation shaft 13, and the middle plate 14 rotates when feeding the seat to lift the seat upward. The separate feeding unit 12 includes a pickup roller 15 that feeds the sheet lifted by the middle plate 14, and a separation roller pair 16 that separates the sheets fed by the pickup roller 15 one by one. ..

The manual feed feeding unit 20 includes a manual feed tray 21 capable of loading sheets and a separate feeding unit 22 for separately feeding the sheets loaded on the manual feed tray 21 one by one. The manual feed tray 21 is rotatably supported by the main body 830 of the multifunction device, and when manually feeding and feeding, the sheet can be loaded by fixing the manual feed tray 21 at a predetermined angle. The separation feeding unit 22 includes a pickup roller 23 that feeds the sheets loaded on the manual feed tray 21, a separation roller 24 and a separation pad 25 that separate the sheets fed by the pickup roller 23 one by one. I have.

The image forming unit 30 includes four process cartridges 31Y to 31K for forming images of yellow (Y), magenta (M), cyan (C), and black (K), and photoconductor drums 740Y to 740K described later. 32, a transfer unit (transfer means) 33 for transferring the toner image formed on the surface of the photoconductor drums 740Y to 740K to the sheet, and a fixing unit 34 for fixing the transferred toner image to the sheet. And have. The alphabet (Y, M, C, K) attached to the end of the code indicates each color (yellow, magenta, cyan, black).

Each of the four process cartridges 31Y to 31K is configured to be removable from the main body 830 of the multifunction device and can be replaced. Since the four process cartridges 31Y to 31K have the same configuration except that the colors of the images to be formed are different, only the configuration of the process cartridge 31Y that forms the yellow (Y) image will be described, and the process cartridge 31M will be described. The description of ~ 31K will be omitted.

The process cartridge 31Y includes a photoconductor drum 740Y as an image carrier, a charger 741Y for charging the photoconductor drum 740Y, a developing device 742Y for developing an electrostatic latent image formed on the photoconductor drum 740Y, and photosensitivity. It includes a drum cleaner 743Y that removes toner remaining on the surface of the body drum 740Y. The developing device 742Y includes a developing device main body (not shown in detail) for developing the photoconductor drum 740Y, and a toner cartridge (not shown in detail) for supplying toner to the developing device main body. The toner cartridge is configured to be removable from the developing device main body, and when the stored toner is exhausted, the toner cartridge can be removed from the developing device main body and replaced.

The exposure apparatus 32 includes a light source for irradiating the laser beam (not shown), a plurality of mirrors (not shown) for guiding the laser beam to the photoconductor drums 740Y to 740K, and the like. The transfer unit 33 is an intermediate transfer belt 35 that carries a toner image formed on the photoconductor drums 740Y to 740K, and a primary transfer roller that first transfers the toner image formed on the photoconductor drums 740Y to 740K to the intermediate transfer belt 35. It includes 36Y to 36K, a secondary transfer roller 37 that secondarily transfers the toner image transferred to the intermediate transfer belt 35 to the sheet, and a belt cleaner 38 that removes the toner remaining on the intermediate transfer belt 35. The intermediate transfer belt 35 is hung on the driving roller 39a and the driven roller 39b, and is pressed against the photoconductor drums 740Y to 740K by the primary transfer rollers 36Y to 36K. The secondary transfer roller 37 nips (sandwiches) the intermediate transfer belt 35 with the drive roller 39a, and transfers the toner image carried by the intermediate transfer belt 35 to the sheet at the nip portion N. The fixing portion 34 includes a heating roller 34a for heating the sheet and a pressurizing roller 34b for pressure contacting the heating roller 34a. Here, the heating roller 34a is heated by the heater described above.

The operation panel unit 843 includes a display unit 845 that displays predetermined information, and an input unit 847 that allows the user to input instructions to the document reading device 820 and the multifunction device main body 830. In the present embodiment, the operation panel unit 843 is arranged on the front side of the reading device main body 822. The front side corresponds to the front side of the paper surface of FIG. 14, and the back side corresponds to the back side of FIG.

As shown in FIG. 15, the arithmetic processing unit 841 includes a CPU 841a that drives and controls a sheet feeding unit 10, a manual feeding unit 20, an image forming unit 30, and a document reading device 820, and various programs for operating the CPU 841a. It includes a memory 841b for storing various information and the like used by the CPU 841a. The arithmetic processing unit 841 integrates and controls the operations of the sheet feeding unit 10, the manual feeding feeding unit 20, the image forming unit 30, and the document reading device 820 based on the operation of the operation panel unit 843 by the user. Let the sheet form an image.

Next, an image forming operation (image forming control by the arithmetic processing unit 841) by the multifunction device 800 configured as described above will be described. In the present embodiment, the image forming unit 30 forms the image of the scanned document fed by the document automatic feeding unit 824 and read by the reading device main body 822 on the sheet fed by the sheet feeding unit 10. An image forming operation will be described as an example.

When the image formation start signal is transmitted by the input to the input unit 847 of the operation panel unit 843 by the user, the scanned document placed on the document automatic feeding unit 824 by the user is automatically directed toward the document reading position. The image is fed and the image is read by the reading device main body 822 at the document reading position.

When the image of the original document is read by the scanning apparatus main body 822, the exposure apparatus 32 irradiates the photoconductor drums 740Y to 740K with a plurality of corresponding laser beams based on the image information of the scanned document. At this time, the photoconductor drums 740Y to 740K are precharged by the chargers 741Y to 741K, respectively, and the corresponding electrostatic latent laser beams are irradiated on the photoconductor drums 740Y to 740K. An image is formed. After that, the electrostatic latent images formed on the photoconductor drums 740Y to 740K are developed by the developing devices 742Y to 742K, and yellow (Y), magenta (M), and cyan (C) are developed on the photoconductor drums 740Y to 740K. ) And black (K) toner images are formed. The toner images of each color formed on the photoconductor drums 740Y to 740K are superimposed and transferred to the intermediate transfer belt 35 by the primary transfer rollers 36Y to 36K, and the superimposed transferred toner image (full-color toner image) is the intermediate transfer belt. It is conveyed to the nip portion N while being carried on the 35.

In parallel with the image forming operation described above, the sheets loaded on the sheet loading unit 11 are fed to the sheet transport path 26 by the pickup roller 15 while being separated one by one by the separate feeding unit 12. Then, the resist roller pair 27 located upstream in the sheet transport direction of the nip portion N corrects the skew and transports the nip portion N to the nip portion N at a predetermined transport timing. A full-color toner image carried by the intermediate transfer belt 35 is transferred to the sheet conveyed to the nip portion N by the secondary transfer roller 37.

The sheet on which the toner image is transferred is heated and pressurized by the fixing unit 34 to melt and fix the toner image, and is discharged to the outside of the device by the discharge roller pair 18. The sheet discharged to the outside of the device is loaded on the discharge sheet loading unit 19.

When images are formed on both sides (first surface and second surface) of the sheet, the discharge roller pair 18 is rotated in the reverse direction before the sheet on which the image is formed on the first surface is discharged to the outside of the apparatus. Then, the image is conveyed to the double-sided transfer path 17, and is retransmitted to the image forming unit 30 via the double-sided transfer path 17. Then, as with the first surface, an image is formed on the second surface and discharged to the outside of the device. The sheet discharged to the outside of the device is loaded on the discharge sheet loading unit 19.

The present invention can be practiced in various other forms without departing from its spirit or key features. Therefore, each of the above embodiments is merely an example and should not be construed in a limited manner. The scope of the present invention is shown by the scope of claims and is not bound by the text of the specification. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

The present invention can be used to drive a fixing heater.

303 Light source discrimination unit 305 Drive method selection unit 307A Heater drive unit A
307B Heater drive unit B
309 Switch 311 Fixing heater 34a Heating roller 34b Pressurizing roller 800 Multifunction device 820 Document reader

Claims (11)

A light source discriminating means for discriminating the type of light source that shares an AC power supply with the multifunction device,
A drive method selection means for selecting a method for driving a heater used in the heating and fixing device of the multifunction device based on the type of the light source determined by the light source determination means.
A heater driving means for driving the heater by the method selected by the driving method selecting means,
A heater drive device characterized by being provided with. The heater drive device according to claim 1.
The heater driving means
At least, a fluorescent lamp-compatible heater driving means corresponding to the case where the light source is a fluorescent lamp, and
At least an LED-compatible heater driving means corresponding to the case where the light source is an LED light source,
With
The drive method selection means
When the light source determining means determines that the light source is a fluorescent lamp, the fluorescent lamp compatible heater drive method is selected as the method for driving the heater.
A heater driving device, characterized in that, when the light source is determined to be an LED by the light source determining means, the LED-compatible heater driving method is selected as the method for driving the heater. The heater drive device according to claim 2.
The drive method selection means
A heater driving device, characterized in that, when it is determined that the light source is neither a fluorescent lamp nor an LED, the fluorescent lamp compatible heater driving method is selected as the method for driving the heater. The heater drive device according to claim 2.
The drive method selection means
A heater driving device, characterized in that, when it is determined that the light source is neither a fluorescent lamp nor an LED, the LED-compatible heater driving method is selected as the method for driving the heater. The heater drive device according to any one of claims 2 to 4.
The heater driving means corresponding to a fluorescent lamp is a heater driving device characterized by being a phase control driving means for driving the heater by an AC phase control method. The heater drive device according to any one of claims 2 to 5.
The LED-compatible heater driving means is a heater driving device that drives the heater with an amplitude-modulated AC power supply. The heater drive device according to any one of claims 1 to 6.
The light source discriminating means is a heater driving device for determining whether or not the light source is an LED based on the intensity ratio of the red component, the blue component, and the green component of the light source. The heater drive device according to any one of claims 1 to 7.
The image sensor included in the image reader included in the multifunction device receives the light from the light source,
The light source discriminating means is a heater driving device characterized in that the type of the light source is discriminated based on the light received by the image pickup device. The heater drive device according to any one of claims 1 to 7.
The image pickup element of the dedicated image pickup device provided in the multifunction device or the image pickup element of the image pickup device provided separately from the multifunction device receives the light from the light source.
The light source discriminating means is a heater driving device characterized in that the type of the light source is discriminated based on the light received by the image pickup device. A multifunction device including the heater driving device according to any one of claims 1 to 9. A light source determination step that determines the type of light source that shares AC power with the multifunction device,
A drive method selection step for selecting a method for driving a heater used in the heating and fixing device of the multifunction device based on the type of the light source determined by the light source determination step.
A heater drive hand step that drives the heater by the method selected by the drive method selection step,
A heater driving method characterized by having.

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