JP2010181567A - Fixing heater control device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing heater control device that normally exerts the control of the supply of power to a fixing heater even if a power source frequency frequently changes, and to provide image forming apparatus. <P>SOLUTION: After the power source is turned on, the power source frequency of an AC power received from an external power source is repeatedly detected and the detected power source frequency is stored. Then, when the supply of power to the fixing heater is started, the control device exerts a through-up control such that the time for which power is supplied is gradually increased for each period of the AC power. In this case, each time the power source voltage has a zero level, the control device refers to the power source frequency and a standby time number (S802, S803) and reads a standby time (S804) with reference to a standby time table. Thus, a power supply time is determined according to the power source frequency and, therefore, the through-up control is normally exerted even if the power source frequency changes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing heater control device and an image forming apparatus, and more particularly, to a technique for controlling the amount of current supplied to a fixing heater in accordance with fluctuations in power supply frequency.

  In an image forming apparatus that performs heat fixing using a heater lamp, an inrush current generated when the heater lamp is turned on affects other loads in the same power supply system, such as flickering of a fluorescent lamp, or a transistor for driving the heater lamp In order to prevent a switching element such as a triac or the like from being destroyed, through-up control for gradually increasing the amount of current at the start of energization and through-down control for gradually decreasing the amount of current at the end of energization are performed.

FIG. 11 is a waveform diagram showing the relationship between the power supply voltage received by the image forming apparatus, the zero cross signal, the heater lighting signal, and the heater current. The zero cross signal is a signal that becomes L level when it is detected that the power supply voltage has reached zero level.
The heater lighting signal is a signal that becomes L level after a predetermined standby time (T1 to T40) has elapsed from the time of falling of the zero cross signal, and returns to H level at the next falling of the zero cross signal. The heater current is supplied to the heater lamp during the period when the heater lighting signal is at the L level.

Now, as shown in FIG. 11, the standby time is preset so as to gradually decrease from T1 to T40, and both are shorter than the half cycle of the power supply voltage. During the through-up period, the energization time and energization voltage to the heater lamp gradually increase by gradually decreasing the standby time.
In the through-down period, the energizing time and energizing voltage for the heater lamp are gradually decreased by gradually increasing the waiting time from T40 to T1. In this way, problems due to large currents entering the heater lamp are avoided.

However, the frequency of the power supply voltage (hereinafter referred to as “power supply frequency”) may fluctuate for some reason, and such fluctuation may prevent accurate execution of the through-up control and the through-down control. FIG. 12 is a waveform diagram showing the power supply voltage, the zero cross signal, and the heater lighting signal before and after the power supply frequency is increased.
As shown in FIG. 12, consider a case where AC power having a frequency (solid line) higher than a frequency (broken line) where the power supply frequency is assumed is supplied. For example, this corresponds to a case where an image forming apparatus assumed to be used in an area where the power supply frequency is 50 Hz is used in an area where the power supply frequency is 60 Hz.

Since the cycle of the power supply voltage is shortened, the fall of the next zero cross signal occurs before the standby time T1 elapses from the fall of the zero cross signal. Then, the waiting time T1 is set again in the timer and no timeout occurs, so the heater lighting signal is held at the H level.
If the state where the power supply frequency is high continues, the heater lighting signal does not switch to the L level and the heater current is not supplied to the heater lamp. However, if power is supplied to the heater lamp after detecting the power supply frequency, the warm-up time of the fixing device becomes long, and it takes time to start image formation.

  For this reason, for example, a technique has been proposed in which the power supply frequency detected at the time of starting the image forming apparatus is recorded in a nonvolatile memory and through-up control is performed using the power supply frequency recorded at the next start-up. In this way, even when the image forming apparatus is used in an area of a power supply frequency different from the assumed power supply frequency, the through-up control can be correctly performed at the second and subsequent startups.

JP 2004-146366 A JP 2007-47211 A JP 2005-91965 A

However, the through-up control and the through-down control are performed at times other than when the image forming apparatus is activated or when the power is turned off. For example, in the case of having the energy saving mode, the through-down control is performed at the time of transition to the energy saving mode, and the through-up control is performed at the time of returning from the energy saving mode.
For this reason, when the power supply frequency is unstable and tends to deviate from the rating, the through-up control and the through-down control may not be performed correctly at the transition between the normal mode and the energy saving mode. In other words, if the power supply frequency deviates from the value detected when the image forming apparatus is activated, there is a possibility that energization of the heater lamp cannot be started or cannot be ended.

Such a problem may occur even in an image forming apparatus using a fixing heater other than the heater lamp when the heater consumes a large current.
The present invention has been made in view of the above problems, and a fixing heater control device and an image that can normally execute energization control to the fixing heater even when the power supply frequency fluctuates frequently. An object is to provide a forming apparatus.

  In order to achieve the above object, the fixing heater control device according to the present invention gradually receives the AC power from the external power source and gradually increases the energizing time every half cycle of the AC power when starting the power supply to the fixing heater. A fixing heater control device that performs at least one of through-up control and through-down control that gradually reduces the energization time for each cycle of the AC power when stopping the power supply to the fixing heater, A frequency detection means for repeatedly detecting the power supply frequency; and at least a newly detected power supply frequency, when the detected power supply frequency fluctuates from the power supply frequency detected immediately before, a frequency storage means for storing the newly detected power supply frequency; Energization time determining means for determining the energization time using a power frequency stored after the last detected power frequency fluctuates. I am characterized in.

  In this way, since the power supply frequency is repeatedly detected and the energization time is determined according to the detected power supply frequency, through-up control and through-down control can be normally executed even if the power supply frequency varies. . Therefore, since it is possible to eliminate the extension of the warm-up time due to the fact that the through-up control is not normally executed, the down time can be reduced.

Even if the power supply frequency is slightly deviated from the rated value, the through-up control and the through-down control can be executed normally, so that problems caused by fluctuations in the power supply frequency can be reduced. Further, it can operate normally regardless of the installation area of the fixing heater control device.
In this case, if the frequency storage means stores the power supply frequency in a non-volatile memory, the power supply detected last time when the through-up control is performed after the power is turned on until a new power supply frequency is detected. Since the frequency can be used, the through-up control can be performed more reliably.

In addition, an energization time storage unit that stores the energization time in association with a power supply frequency is provided, and the energization time determination unit is stored in the frequency storage unit among the energization times stored in the energization time storage unit. The energization time may be determined by referring to the energization time associated with the power frequency. In this way, the energization time can be easily determined.
Alternatively, the energization time determination means may calculate the energization time using the power supply frequency stored in the frequency storage means. In particular, the energization time determination means is stored in the frequency storage means. It is preferable to calculate the energization time by dividing the predetermined value by the power frequency. In this way, a more appropriate energization time can be determined according to the power supply frequency.

In addition, the storage unit for storing the installation area of the own device, and a specifying unit for specifying the power supply frequency from the installation region, the energization time determination unit, until the power supply frequency is detected after turning on the power, The energization time is determined using a power supply frequency specified from an installation area.
Since the rated value of the power supply frequency can be determined from the installation location of the fixing heater device, the fixing heater device can be used in this way when through-up control is performed after the power is turned on until the power supply frequency is detected. An appropriate energization time can be determined according to the installation location.

In this case, a receiving unit for receiving designation of the installation area of the own device from a user is provided, and the storage unit may store the installation area received by the receiving unit. In particular, the receiving unit receives the designation. It is preferable that an operation panel is provided or that the accepting unit accepts the designation from another device via a network.
The image forming apparatus according to the present invention includes the fixing heater control device according to the present invention. In this way, an image forming apparatus having the effects as described above can be obtained.

1 is a diagram illustrating a main configuration of an image forming apparatus according to an embodiment. 3 is a block diagram illustrating a main configuration of a control unit 101. FIG. 2 is a circuit diagram illustrating a main configuration of a zero-cross signal generation circuit 200. FIG. It is a flowchart which shows the main steps of the detection process of a power supply frequency. It is a figure which shows the data structure which records the detected power supply frequency and frequency state in the non-volatile memory. 4 is a flowchart showing main steps of frequency control executed by a printer unit 210. It is a flowchart which shows the main steps of a through-up control process. It is a flowchart which shows the main steps of the interruption processing program for performing through-up control and through-down control. It is an example of a waiting time table. It is a flowchart which shows the main steps of a timer interruption processing program. FIG. 4 is a waveform diagram showing a relationship between a power supply voltage received by the image forming apparatus, a zero cross signal, a heater lighting signal, and a heater current. It is a wave form diagram which shows the power supply voltage before and behind a power supply frequency becoming high, a zero cross signal, and a heater lighting signal.

Embodiments of a fixing heater control device and an image forming apparatus according to the present invention will be described below with reference to the drawings.
[1] Configuration of Image Forming Apparatus First, the configuration of the image forming apparatus according to the present embodiment will be described.
FIG. 1 is a diagram illustrating a main configuration of an image forming apparatus according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 is a tandem color image forming apparatus, and includes a power supply device 100, a control unit 101, an image reading unit 110, an image forming unit 120, a sheet storage unit 130, and a sheet conveyance unit. Part 140 is provided.

The power supply device 100 receives supply of AC power from the external power supply 150 and supplies power into the apparatus. The control unit 101 controls the overall operation of the image forming apparatus 1.
The image reading unit 110 includes a loading table 111, a conveying unit 112, a document table glass 113, a scanner 114, and a discharging table 115, and a document placed on the loading table 111 is read by the conveying unit 112 according to a user instruction. Each sheet is taken out and conveyed onto the platen glass 113.

The document on the document table glass 113 is read by the scanner 114 and discharged onto the discharge table 115. The scanner 114 includes three rows of CCD (Charge Coupled Device) line sensors corresponding to the three primary colors, and reads an original to generate image data of each color.
The scanner 114 may be a sheet-through system that reads a document by passing paper while the CCD line sensor is stationary. In addition, an original placed on the original platen glass 113 is exposed using an exposure lamp and a reflection mirror that move in parallel with the original platen glass 113, and the reflected light is sent to the CCD line sensor by a plurality of reflection mirrors. Image data may be generated by guiding the image data.

The image forming unit 120 includes an intermediate transfer belt 121, rollers 122 to 124, image forming units 125Y to 125K, primary transfer rollers 126Y to 126K, a cleaning device 127, a fixing device 128, and a paper discharge tray 129.
The intermediate transfer belt 121 is stretched around rollers 122 to 124. The image forming units 125Y to 125K are arranged in the order of yellow (Y), M (magenta), C (cyan), and black (K) along the intermediate transfer belt 121, and are based on image data generated by the scanner 114. YMCK color toner images are formed.

The toner images formed by the image forming units 125Y to 125K are electrostatically transferred so as to overlap on the intermediate transfer belt 121 at the timings of the primary transfer rollers 126Y to 126K, respectively. Thereby, a color image is formed.
The paper storage unit 130 includes a paper feed cassette 131. A recording sheet is stored in the paper feed cassette 131. The paper storage unit 130 may include a plurality of paper feed cassettes having different sizes of recording sheets to be stored, and may feed recording sheets having a size specified by the user.

The paper transport unit 140 includes rollers 141 to 144. The roller 141 is a so-called pickup roller, and takes out recording sheets stored in the sheet feeding cassette 131 one by one. The taken out recording sheet is further conveyed by a roller 142.
The roller 143 is a so-called secondary transfer roller, and electrostatically transfers the toner image on the intermediate transfer belt 121 onto the recording sheet. Thereafter, the toner remaining on the intermediate transfer belt 121 is scraped off by the cleaning device 127 and discarded.

  The fixing device 128 melts a toner image on a recording sheet by a heating roller, a pressure roller, and a heater lamp (not shown) and fuses the toner image to the recording sheet. The roller 144 is a so-called paper discharge roller, and discharges the recording sheet on which the toner image is fixed onto the paper discharge tray 129. Note that the control unit 101 performs through-up control and through-down control when the power supply apparatus 100 supplies power to the fixing device 128.

[2] Configuration of Control Unit 101 Next, the configuration of the control unit 101 will be described.
FIG. 2 is a block diagram illustrating a main configuration of the control unit 101. As shown in FIG. 2, the control unit 101 includes a printer unit 210, a system controller unit 220, and an operation panel unit 221.

The printer unit 210 includes a CPU (Central Processing Unit) 211, a ROM (Read Only Memory) 212, a RAM (Random Access Memory) 213, a nonvolatile memory 214, a timer 215, and an input / output interface 216. Supervises image forming operations.
The operation panel unit 221 includes a touch panel and hard keys, and displays information and receives instruction inputs to the user. The system controller unit 220 controls the printer unit 210 and the operation panel unit 221.

The CPU 211 reads a program for controlling the image forming operation from the ROM 212 and operates using the RAM 213 as a work area. The CPU 211 controls the power supply device 100, the image forming units 125Y to 125K, the fixing device 128, and the like via the input / output interface 216, and acquires information from these devices.
The power supply apparatus 100 includes a zero-cross signal generation circuit 200 that detects a zero-cross point of AC power supplied from the external power supply 150, and the CPU 211 detects a power supply frequency using the zero-cross signal. Further, the CPU 211 performs through-up control and through-down control by setting a predetermined time in the timer 215 and outputting a trigger pulse together with the timeout.

[3] Zero-cross signal generation circuit 200
The zero cross signal generation circuit 200 will be described.
FIG. 3 is a circuit diagram illustrating the main configuration of the zero-cross signal generation circuit 200. As shown in FIG. 3, the zero-cross signal generation circuit 200 includes resistors R301 to R304, a capacitor C311, a diode bridge BR321, a photocoupler PC331, and a hysteresis inverter IC341.

The resistors R301 and R302 and the capacitor C311 constitute a low-pass filter and receive AC power from the external power supply 150. This circuit also has a current limiting function. The AC power is subjected to full-wave rectification by the diode bridge BR321 after passing through a low-pass filter.
The photocoupler PC331 transmits the input signal and the output signal in an electrically insulated state. The output signal of the photocoupler PC331 is input to the hysteresis inverter IC341, and a rectangular wave (zero cross signal) is generated. Resistors R303 and R304 are pull-up resistors for applying a positive voltage. The generated zero cross signal is input to the two interrupt terminals of the CPU 211. One interrupt terminal (hereinafter referred to as “detection terminal”) is used to detect the power supply frequency, and the other interrupt terminal (hereinafter referred to as “control terminal”) is through-up control or through-down control. Used for.

[4] Power Frequency Detection Processing Next, the printer unit 210 periodically executes the following processing to detect the power frequency.
FIG. 4 is a flowchart showing the main steps of the power supply frequency detection process. As shown in FIG. 4, the printer unit 210 first clears the interrupt counter as the power frequency detection process (S401). In the present embodiment, the interrupt counter refers to a predetermined area on the RAM 213 and indicates a positive integer value. The interrupt counter value is initialized to zero by the process of step S401.

Next, a predetermined time (500 milliseconds in the present embodiment) is set in the timer (S402). In this embodiment, the power supply frequency is detected by counting the number of zero cross points in 500 milliseconds.
Next, the interrupt mask of the detection terminal is canceled (S403). This interrupt mask masks an interrupt generated by the falling timing of the zero cross signal input to the detection terminal. By canceling this mask, an interrupt processing program corresponding to the detection terminal is started every time the zero cross signal falls.

The interrupt processing program activated at the falling timing of the zero cross signal increments the interrupt counter by 1 each time it is activated. Since the power supply voltage reaches the zero level twice during one cycle, the number of interruptions for 500 milliseconds directly indicates the frequency of the power supply voltage.
Thereafter, when a timeout occurs (S404: YES), the interrupt is masked (S405) and the interrupt counter is referred to. When the value of the interrupt counter is less than 45 or exceeds 64, it is determined that the power supply frequency is abnormal because the power supply frequency is less than 45 Hz or exceeds 64 Hz, otherwise it is determined to be normal. To do.

When it is determined that the detected power supply frequency is normal (S406: NO), the value of the interrupt counter is recorded in the nonvolatile memory 214, and the fact that the power supply frequency is normal is also recorded in the nonvolatile memory 214. (S407), the process ends.
FIG. 5 is a diagram showing a data structure for recording the detected power supply frequency and frequency state in the nonvolatile memory 214. As shown in FIG. 5, in the present embodiment, in the 16-bit area, the power supply frequency is recorded in 8 bits, and the frequency state is recorded in the next 1 bit. If the stored value is 1, the frequency state indicates that it is normal, and if it is 0, it indicates that it is abnormal.

The reason why 2 bits are assigned as the control flag is to specify whether to perform through-up control or through-down control as interrupt processing, as will be described later. In the present embodiment, as shown in FIG. 5, when the value of the control flag is 1, through-up control is executed, and when it is 0, through-down control is executed.
If it is determined that the detected power frequency is abnormal (S406: YES), the fact that the power frequency is abnormal is recorded in the nonvolatile memory 214 (S408), but the power frequency is not changed and is left as it is. The process ends. This is because if an abnormal power supply frequency is recorded, the next through-up control or through-down control cannot be executed normally.

[5] Frequency control of heater current Next, frequency control of heater current, that is, through-up control and through-down control will be described.
FIG. 6 is a flowchart showing main steps of frequency control executed by the printer unit 210. As shown in FIG. 6, the printer unit 210 first refers to the frequency state recorded in the nonvolatile memory 214 (S601).

If the frequency state is abnormal (S602: YES), the operation panel unit 221 is notified of this (S607), and the process is terminated.
If the frequency state is normal (S602: NO) and energization of the heat lamp is started (S603: YES), a through-up control process is executed (S604). Further, when energization of the heat lamp is stopped (S605: YES), a through-down control process is executed (S606). When the process of step S604 or step S606 is completed, the process proceeds to step S601 and the above process is repeated.

[6] Through-up Control Process and Through-Down Control Process Next, the through-up control process (S604) and the through-down control process (S606) will be described.
The printer unit 210 performs through-up control using an interrupt processing program that is activated when the zero-cross signal input to the control terminal falls and an interrupt processing program that is activated when the timer times out. Through-down control is performed. For this reason, in the through-up control process (S604) and the through-down control process (S606), only the processes necessary for starting the interrupt processing program are performed.

  FIG. 7 is a flowchart showing the main steps of the through-up control process. As shown in FIG. 7, in the through-up control process, the printer unit 210 first sets a value 1 indicating that the through-up control is performed in the control flag (S701), and initializes the standby time number to 1. After that (S702), the mask of the terminal is released (S703). As a result, the through-up control program is activated every time the zero cross signal falls, and through-up control is executed.

The through-down control process (S060) is substantially the same except that the value set in the control flag is 0 and the initial value of the waiting time number is 40.
FIG. 8 is a flowchart showing the main steps of an interrupt processing program for performing through-up control and through-down control. As shown in FIG. 8, when an interrupt is input to the control terminal, first, the heater lighting signal is set to H level (S801). As a result, power supply to the heater lamp is stopped. The heater lighting signal is controlled by sending a control signal to the power supply apparatus 100 via the input / output interface 216 by the CPU 211.

Next, the power frequency and the standby time number recorded in the nonvolatile memory 214 are referred to (S802, S803). Similarly, the standby time corresponding to the power supply frequency and the standby time number is read from the standby time table on the nonvolatile memory 214 (S804). FIG. 9 illustrates a standby time table.
As shown in FIG. 9, standby times assigned with standby time numbers from 1 to 40 are recorded corresponding to two power supply frequencies of 50 Hz and 60 Hz. In the present embodiment, when the power supply frequency is in the range of 45 Hz to 54 Hz, the standby time in the column of 50 Hz is used, and when in the range of 55 Hz to 64 Hz, the standby time in the column of 60 Hz is used. It is done.

When the standby time is determined, the standby time is set in the timer (S805), and the interrupt process is terminated. As a result, after the waiting time has elapsed, the corresponding interrupt processing program is started by a timer interrupt, and the following processing is executed.
FIG. 10 is a flowchart showing the main steps of the timer interrupt processing program. As shown in FIG. 10, when the timer interrupt processing program is started, first, the heater lighting signal is set to L level (S1001). As a result, power supply to the heater lamp is started.

Next, referring to the control flag on the non-volatile memory 214 (S1002), if the value is 1 (S1003: YES), since it is through-up control, the standby time number is increased by 1 (S1004), and the next Reduce the waiting time to be set in the timer.
When the updated waiting time number exceeds 40 (S1005: YES), the control terminal interrupt is masked to end the through-up control (S1006).

If the value of the control flag is 0 (S1003: NO), since it is through-down control, the waiting time number is decreased by 1 (S1007), and the waiting time to be set next in the timer is increased. If the waiting time number is less than 1 (S1008: YES), the control terminal interrupt is masked to end the through-down control (S1006).
[7] Summary As described above, the image forming apparatus according to the present embodiment periodically detects the power supply frequency, records the power supply frequency in the nonvolatile memory, and sets the power supply frequency read from the nonvolatile memory. Accordingly, the through-up control and the through-down control are performed, so that the through-up control and the through-down control can be appropriately performed even when the power supply frequency fluctuates frequently.

[8] Modifications While the present invention has been described based on the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and the following modifications can be implemented. .
(1) In the above embodiment, the case where the power supply frequency is detected exclusively by counting the zero cross points has been described. However, it goes without saying that the present invention is not limited to this, and in addition, as follows. Also good.

In other words, in Japan, the rated value of the power supply frequency is different between the east and west regions, and the initial value of the power supply frequency is determined according to the area where the image forming apparatus is installed. The power supply frequency detected by counting may be used.
The installation area of the image forming apparatus may be determined using GPS (Global Positioning System) every time the power is turned on, or input to the user through the operation panel unit 221 every time the installation location is changed. The installed area may be recorded in the nonvolatile memory 214. Further, the installation area of the image forming apparatus may be input to the user using another apparatus connected to the image forming apparatus via a network.

Then, a table for associating the installation area with the power supply frequency may be recorded in advance on the nonvolatile memory 214, and an initial value of the power supply frequency may be determined from the specified installation area.
In this way, since the warming up of the fixing device can be started sooner after the image forming apparatus is turned on, the waiting time for the user can be reduced and the convenience thereof can be improved.

(2) Although not particularly mentioned in the above embodiment, the period for periodically detecting the power supply frequency may be, for example, every hour or every 10 minutes. Further, it may be performed immediately before starting the through-up control or the through-down control, or may be executed periodically such as every 10 seconds after the start of these controls.
In particular, if the power supply frequency is detected immediately before starting through-up control or the like, these controls can be executed with high accuracy. If the power supply frequency is detected periodically after the start, control of the power supply frequency during the execution of these controls is possible. Even if fluctuates, through-up control or the like can be normally executed following the fluctuation.

The through-up control is started at a power saving mode in which the fixing temperature is lowered, a return from a sleep mode in which the fixing temperature is not maintained, a power on, or the like. Therefore, in such a case, the power supply frequency may be detected prior to starting the through-up control.
(3) In the above embodiment, the case has been described where the detected power supply frequency is less than 45 Hz, or when the detected power supply frequency is abnormal when it exceeds 64 Hz, but the present invention is not limited to this. Needless to say, the same effect can be obtained even if the range of the power supply frequency determined to be abnormal is different.

Further, if the power supply frequency is less than 30 Hz or exceeds 125 Hz, etc., and it may deviate greatly from the rated value, and the image forming apparatus may be destroyed, it should be judged as abnormal.
(4) In the above-described embodiment, the case where the power supply frequency is detected by counting the number of zero cross points during a period of 500 milliseconds has been described. Needless to say, the present invention is not limited to this. The zero cross point during the period of the length may be counted, or the power supply frequency may be detected by a method other than counting the zero cross point. Regardless of the method of detecting the power supply frequency, the present invention can be effective.

(5) In the above embodiment, the case of using a table that defines the standby time for each power supply frequency has been described. Needless to say, the present invention is not limited to this, and the following may be used instead. good.
For example, in FIG. 9, for each standby time number, the value obtained by multiplying the power supply frequency and the corresponding standby time is substantially equal regardless of the power supply frequency. Therefore, a table indicating values obtained by multiplying the power supply frequency and the corresponding standby time for each standby time number is recorded on the nonvolatile memory 214, and the multiplication value is divided by the detected power supply frequency. The waiting time may be determined accordingly.

Also, if the power supply frequency fluctuates after the start of through-up control, etc., the standby time is determined so that the energization time before and after the change, that is, the time obtained by subtracting the standby time from the cycle of the power supply frequency is approximately equal. May be. Further, the standby time may be determined so that the amount of electric power supplied to the heater lamp becomes substantially equal instead of the energization time.
In this way, fluctuations in the amount of supply current caused by fluctuations in the power supply frequency can be suppressed, so various problems caused by fluctuations in the supply current amount, that is, effects on other loads that share the same power supply system, , Damage to the machine parts can be suppressed.

  (6) In the above embodiment, the case where both the through-up control and the through-down control are executed with reference to the detected power supply frequency has been described, but it goes without saying that the present invention is not limited to this. Only one of the through-up control and the through-down control may be executed with reference to the power supply frequency. If it does in this way, the effect of the present invention can be acquired about the control performed with reference to the power supply frequency concerned.

(7) In the above embodiment, the image forming apparatus that performs the fixing process using the heater lamp has been described as an example. However, the present invention is not limited to this, and a heat source other than the heater lamp may be used. In the case of using a heat source that requires a large current, the effect can be obtained by applying the present invention.
(8) In the above embodiment, the case where the printer unit 210 controls the power supply device 100 to detect the power supply frequency or perform the through-up control has been described. Needless to say, the power supply apparatus 100 itself may perform these processes, or the fixing device 128 may perform the processes. Moreover, these apparatuses may share the processing.

  (9) In the above embodiment, the case where the power supply frequency is detected by counting the number of zero cross points within a fixed time has been described. Needless to say, the present invention is not limited to this. The power supply frequency may be detected by a method other than counting. As such a method, for example, the time required for one cycle of the power supply frequency may be obtained.

(10) In the above embodiment, the case where only the last detected power supply frequency is recorded in the nonvolatile memory 214 each time the power supply frequency is detected has been described, but it goes without saying that the present invention is not limited to this. For example, it may be as follows.
That is, the latest plurality of detected power supply frequencies may be recorded as history information. Further, it may be recorded in the non-volatile memory 214 only when the newly detected power supply frequency is different from the previously detected power supply frequency, or the latest plurality of new power supply frequencies different from the previously detected power supply frequency. May be recorded. In either case, the effect of the present invention is the same.

  The fixing heater control apparatus and the image forming apparatus according to the present invention are useful as an apparatus that can normally execute energization control to the fixing heater even when the power supply frequency fluctuates frequently.

1 ……………………… Image forming apparatus 100 ………………… Power supply device 101 ………………… Control unit 110 …………………… Image reading unit 120 …………… …… Image forming unit 128 …………………… Fixer 130 …………………… Paper storage unit 140 …………………… Paper transport unit 150 ……………… External power source 200 …… ... ………… Zero cross signal generation circuit 210 ………………… Printer 220 ………………… System controller 221 ………………… Operation panel 214 ………………… Non-volatile Memory 215 …………………… Timer 216 …………………… I / O interface

Claims (10)

When receiving AC power from an external power source and starting the power supply to the fixing heater, through-up control that gradually increases the energization time every half cycle of the AC power, and the AC when stopping the power supply to the fixing heater A fixing heater control device that performs at least one of through-down control that gradually decreases energization time for each cycle of power,
Frequency detection means for repeatedly detecting the power supply frequency after turning on the power;
When at least the newly detected power supply frequency fluctuates from the power supply frequency detected immediately before, frequency storage means for storing the newly detected power supply frequency;
A fixing heater control device comprising: energization time determining means for determining the energization time using a power frequency stored after the detected power frequency has changed last. The fixing heater control device according to claim 1, wherein the frequency storage unit stores a power supply frequency in a nonvolatile memory. An energization time storage means for storing the energization time in association with a power supply frequency;
The energization time determining means determines the energization time by referring to the energization time associated with the power supply frequency stored in the frequency storage means among the energization times stored in the energization time storage means. The fixing heater control device according to claim 1. The fixing heater control apparatus according to claim 1, wherein the energization time determination unit calculates an energization time using the power supply frequency stored in the frequency storage unit. 5. The fixing heater control device according to claim 4, wherein the energization time determination unit calculates the energization time by dividing a predetermined value by the power supply frequency stored in the frequency storage unit. Storage means for storing the installation area of the aircraft;
And a specifying means for specifying the power supply frequency from the installation area,
2. The fixing according to claim 1, wherein the energization time determination unit determines the energization time using a power supply frequency specified from the installation area until a power supply frequency is detected after power is turned on. Heater control device. It has a reception means that accepts designation of the installation area from the user,
The fixing heater control apparatus according to claim 6, wherein the storage unit stores an installation area received by the reception unit. The fixing heater control apparatus according to claim 7, wherein the reception unit includes an operation panel that receives the designation. The fixing heater control device according to claim 7, wherein the reception unit receives the designation from another device via a network. An image forming apparatus comprising the fixing heater control device according to claim 1.

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