JP2020112742A - Image forming apparatus and method for controlling the same - Google Patents

Abstract

To provide a technology that deals with a change in a zero-cross signal in every operation mode.SOLUTION: An image forming apparatus 100 comprises: a power supply unit 207 that supplies an alternating current from an alternating current power supply 214 to an image forming apparatus 100; a fixing unit 108 that has a heater 213 built therein; a zero-cross signal generation unit 208 that generates a zero-cross signal based on the alternating current; a trigger signal generation unit 209 that generates a trigger signal based on rising of the zero-cross signal; a delay control unit 210 that delays rising of the trigger signal; and a control unit 201. The zero-cross signal generation unit 208 generates the zero-cross signal in every operation mode of the image forming apparatus 100; the trigger signal generation unit 209 generates the trigger signal based on the zero-cross signal in every operation mode; the delay control unit 210 delays the rising of the trigger signal in every operation mode; the control unit 201 supplies the alternating current to the fixing unit 108 based on the delay in the rising of the trigger signal in every operation mode.SELECTED DRAWING: Figure 12

Description

The present disclosure relates to control of fixing devices, and more particularly to zero-cross control of trigger signals.

In an electrophotographic image forming apparatus, toner forms an image on a transfer image carrier such as a photosensitive drum. Then, the charger transfers the toner on the transfer image carrier onto a transfer medium such as paper. After the transfer of the toner to the transfer medium, the toner fixing unit having a heat generating mechanism heats the transfer medium on which the toner has been transferred, and fixes the toner on the transfer medium.

Usually, the toner fixing unit has a built-in heater and the like, and an alternating current of a commercial power source is used for heating the heater. The alternating current supplied to the toner fixing unit is phase-controlled, and further, a zero-cross signal corresponding to the zero-cross point of the voltage of the commercial power supply is used for the phase control.

Regarding the zero-cross control, for example, Japanese Unexamined Patent Application Publication No. 2014-149388 (Patent Document 1) "shows an ON state when a pulsating flow obtained by rectifying a supply voltage from an AC power source is lower than a predetermined threshold voltage. A pulse signal is generated, and a trigger signal for driving the load is generated in synchronization with the rising edge of the pulse signal.Next, the trigger signal is delayed every half cycle of the supply voltage, and the load is driven by the delayed trigger signal. At the same time, the current value of the AC power supply is detected at the driving timing, and the detected current value is compared with a predetermined threshold value. By delaying, a trigger signal having a different degree of delay is generated, the current value is further detected, and the detection current value is repeatedly controlled so as to be compared with a predetermined threshold value. A zero-cross point detection method is disclosed if the timing at which the current value is detected is determined to be a zero-cross point if it is equal to or greater than a predetermined threshold (see [Summary]).

JP, 2014-149388, A

According to the technique disclosed in Patent Document 1, it is impossible to deal with the change of the zero-cross signal for each different operation mode. Therefore, there is a need for a technique that responds to changes in the zero-cross signal for each operation mode.

The present disclosure has been made in view of the background as described above, and an object of an aspect is to provide a technique that responds to a change in a zero-cross signal for each operation mode.

An image forming apparatus according to an embodiment generates a zero-cross signal on the basis of an AC power source that supplies AC from an AC power source to the image forming apparatus, a fixing unit that incorporates a heater, and fixes toner on paper. A zero-cross signal generation unit that generates a trigger signal based on the rising edge of the zero-cross signal, a delay control unit that delays the rising edge of the trigger signal, and a control unit that controls the image forming apparatus. The zero-cross signal generation unit generates a zero-cross signal in each operation mode of the image forming apparatus, the trigger signal generation unit generates a trigger signal based on the zero-cross signal of each operation mode, and the delay control unit performs each operation. The rising of the mode trigger signal is delayed, and the control unit supplies alternating current to the fixing unit based on the delay of the rising of the trigger signal of each operation mode.

In one aspect, the image forming apparatus further includes a current measuring unit that measures a current supplied to the fixing unit. Delaying the trigger signal means that the current measuring unit measures the current supplied to the fixing unit, and the control unit starts the AC supply to the fixing unit based on the measured current and then the AC Until the next zero cross point occurs, the amount of power supplied to the fixing unit is calculated, and the delay control unit delays the trigger signal based on the amount of power and the rising edge of the trigger signal is set to the zero cross point. To match the timing of occurrence of.

In one aspect, the image forming apparatus further includes a storage unit that stores the delay setting of the trigger signal in each operation mode. The control unit stores the setting of the delay of the rising edge of the trigger signal in each operation mode in the storage unit.

In a certain aspect, the control unit obtains the setting of the delay of the rising edge of the trigger signal in each operation mode and stores it in the storage unit at a constant cycle.

In one aspect, the control unit obtains the setting of the rising delay of the trigger signal in each operation mode for each printing process and stores the setting in the storage unit.

In one aspect, the control unit obtains the setting of the delay of the rising edge of the trigger signal in each operation mode and stores the setting in the storage unit each time the main power of the image forming apparatus is turned on.

In one aspect, the control unit obtains the setting of the delay of the rising edge of the trigger signal in each operation mode and saves the setting in the storage unit each time the device returns to sleep.

In a certain aspect, the control unit has a timer function, and for each constant count by the timer function, the control unit obtains the setting of the delay of the rising edge of the trigger signal in each operation mode and stores the setting in the storage unit.

In one aspect, the control unit obtains the setting of the delay of the rise of the trigger signal in each operation mode immediately after the start of lighting the heater and after a predetermined time has elapsed from the start of lighting the heater, and stores the setting in the storage unit.

In one aspect, the control unit obtains the setting of the delay of the rising edge of the trigger signal of each operation mode and stores the setting in the storage unit after a predetermined time elapses after turning off the heater.

In one aspect, the image forming apparatus further includes a communication unit that communicates with an external device. The control unit transmits the setting of the rising delay of the trigger signal to the external server via the communication unit, and acquires the setting of the rising delay of the trigger signal from the external server via the communication unit.

In one aspect, the control unit stores the setting of the rising delay of the trigger signal in the first operation mode as a reference in the storage unit, and sets the setting of the rising delay of the trigger signal in another operation mode as a difference from the reference. Is stored in the storage unit.

In one aspect, the control unit acquires from the storage unit the setting of the delay of the rising edge of the trigger signal according to the scheduled operation state of the image forming apparatus, and uses the setting for the delay control of the rising edge of the trigger signal.

In one aspect, the scheduled operation state of the image forming apparatus includes a standby state and a printing state.
According to another embodiment, a method of controlling an image forming apparatus is provided. In this control method, in each operation mode of the image forming apparatus, a step of generating a zero-cross signal based on an alternating current supplied from an alternating-current power source, and a trigger signal based on a rising edge of the zero-cross signal in each operation mode. Steps, delaying the rising edge of the trigger signal in each operation mode, and supplying alternating current to the fixing unit containing the heater based on the delaying the rising edge of the trigger signal in each operation mode.

In one aspect, the step of delaying the rising edge of the trigger signal includes the step of measuring the current supplied to the fixing unit and the step of measuring the current supplied to the fixing unit based on the measured current. Step of calculating the amount of electric power supplied to the fixing unit until the occurrence of the zero-cross point, and delaying the rising of the trigger signal based on the amount of electric power, and adjusting the rising of the trigger signal to the generation timing of the zero-cross point Including and

In certain aspects, the method further comprises storing the rising delay setting of the trigger signal for each operating mode.

In one aspect, the method finds and stores the setting of the rising delay of the trigger signal in each operation mode at regular intervals.

In one aspect, the method obtains and stores the setting of the rising delay of the trigger signal in each operation mode for each printing process.

In one aspect, the method obtains and stores the setting of the rising delay of the trigger signal in each operation mode every time the main power of the image forming apparatus is turned on.

According to the present technology, it is possible to detect zero-cross points in a plurality of operation modes.
The above as well as other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention which is understood in connection with the accompanying drawings.

1 is a diagram showing a configuration example of an image forming apparatus 100 according to an embodiment. FIG. 3 is a diagram showing an example of a circuit 200 of image forming apparatus 100 according to an embodiment. It is a figure which shows the 1st example of the waveform of the input voltage from the AC power supply according to one embodiment. FIG. 6 is a diagram showing a first example of a relationship between a trigger signal and an output voltage waveform to a heater according to an embodiment. It is a figure which shows the 2nd example of the waveform of the input voltage from the AC power supply according to one embodiment. It is a figure which shows the 2nd example of the relationship of the trigger signal and output voltage waveform to a heater according to a certain embodiment. It is a figure which shows the 3rd example of the relationship of the trigger signal and output voltage waveform to a heater according to a certain embodiment. It is a figure which shows the 3rd example of the waveform of the input voltage from the alternating current power supply according to one embodiment. It is a figure which shows the 4th example of the relationship of the trigger signal and output voltage waveform to a heater according to a certain embodiment. It is a figure which shows the 4th example of the waveform of the input voltage from the alternating current power supply according to one embodiment. It is a figure which shows the 5th example of the relationship of the trigger signal and output voltage waveform to a heater according to a certain embodiment. 7 is an example of a process of obtaining a setting of a delay time of a trigger signal according to an embodiment.

Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<A. Overview of equipment>
First, the configuration of image forming apparatus 100 according to the present embodiment will be described. As a typical example, an image forming apparatus 100 implemented as a multi-functional peripheral (MFP) will be described. The image forming apparatus 100 is, for example, a color image forming apparatus, but the application target of the technical idea according to the present embodiment is not limited to the color image forming apparatus, and the technical idea is applied to the monochrome image forming apparatus. Is also applicable.

FIG. 1 is a diagram showing a configuration example of an image forming apparatus 100 according to the present embodiment. Referring to FIG. 1, the image forming apparatus 100 includes a manual feed tray 101, a paper feed cassette 102, a paper feed roller 103, a registration roller 104, an imaging unit 105, an intermediate transfer belt 106, and a transfer roller 107. The fixing unit 108, the discharge tray 109, and the control unit 110 are included.

The imaging unit 105 includes a photoconductor, a charging section, an exposing section, and a developing section. The imaging unit 105 includes a plurality of imaging units for generating cyan (C), magenta (M), yellow (Y), and key plate (K) toner images, respectively.

The image forming apparatus 100 according to the present embodiment employs, as an example, a configuration in which the toner images generated by the respective imaging units 105 are transferred to the transfer target member via the intermediate transfer belt 106. In the present embodiment, the toner image is once transferred to the intermediate transfer belt 106 and then transferred to the transfer target member. However, the toner image on the photoconductor is directly transferred to the transfer target member. May be done.

The paper is placed on either the manual feed tray 101 or the paper feed cassette 102. The paper feed roller 103 conveys the paper placed on the manual feed tray 101 or the paper feed cassette 102 one by one to the paper conveyance path. The registration roller 104 conveys the paper conveyed by the paper feed roller 103 further downstream. The transfer roller 107 transfers the transfer image on the intermediate transfer belt 106 to the conveyed sheet. The fixing unit 108 melts the toner transferred onto the surface of the paper to fix the toner on the paper. The sheet that has been subjected to the fixing process is discharged to the discharge tray 109. The control unit 110 controls the overall operation of the image forming apparatus 100.

FIG. 2 is a diagram showing an example of the circuit 200 of the image forming apparatus 100 according to the present embodiment. Referring to FIG. 2, a circuit 200 includes a CPU (Central Processing Unit) 210, a storage unit 202, a user interface (hereinafter referred to as UI) 203, a display unit 204, an imaging unit 105, and a communication unit 205. A power supply unit 206, a heater control unit 207, a current sensor 211, a temperature sensor 212, and a heater 213. The heater controller 207 includes a zero-cross signal generator 208, a trigger signal generator 209, and a delay controller 210. The circuit 200 is built in the image forming apparatus 100, and mainly shows a configuration necessary for controlling the fixing unit 108 from the control unit 110. Note that the circuit 200 illustrated in FIG. 2 is an example and may include another structure.

The CPU 201 controls the entire image forming apparatus 100. In one aspect, a microcomputer chip, a SoM (System on Module), a SoC (System-on-a-Chip), and an FPGA (Field-Programmable Gate Array) may be used as the CPU 201.

The storage unit 202 stores various settings regarding the image forming apparatus 100 and information regarding operation modes. In an aspect, an SSD (Solid State Drive) and an eMMC (embedded Multi Media Card) may be used as the storage unit 202.

The UI 203 is provided in the housing of the image forming apparatus 100, receives a command from the user, and sends the acquired command to the CPU 110. In some aspects, a push button or a touch panel may be used as the UI 203. The display unit 204 displays various information such as settings and functions of the image forming apparatus 100 to the user. In some aspects, a liquid crystal monitor may be used as the display unit 204. In still another aspect, the display unit 204 may be realized by a tablet terminal or the like that is detachable from the main body of the image forming apparatus 100.

The communication unit 205 communicates with an external communication device. The communication unit 205 receives a print job, a firmware update command, or the like from an external communication device, and sends the received information to the CPU 201. In an aspect, a LAN (Local Area Network) port, a Wi-Fi (registered trademark) (Wireless Fidelity) transmitter/receiver, or the like may be used as the communication unit 205.

The power supply unit 206 supplies electric power from the AC power supply 214 to the entire image forming apparatus 100. The power supply unit 206 converts a part of electric power acquired from the AC power supply 214 into direct current and supplies the direct current to the control unit 110 and the like. The power supply unit 206 also supplies the alternating current acquired from the alternating-current power supply 214 to the heater control unit 207 and the heater 213.

The heater control unit 207 controls the heater 213 of the fixing unit 108 using the zero-cross signal generation unit 208, the trigger signal generation unit 209, and the delay control unit 210. The zero-cross signal generation unit 208 generates a zero-cross signal based on the alternating current of the alternating current power supply 214. The zero-cross signal is a pulse generated at the timing when the voltage becomes around 0V.

The trigger signal generation unit 209 generates a trigger signal for causing the CPU 201 to detect the timing of turning on the heater. The CPU 201 starts power supply to the heater 213 or increases power supplied to the heater 213 at the timing when the trigger signal is detected. The trigger signal is generated at the rising edge of the zero-cross signal.

The delay controller 210 delays the rising edge of the trigger signal. The rising edge of the zero-cross signal generated by the zero-cross signal generation unit 208 is deviated from the AC zero-cross point. Therefore, the delay control unit 210 delays the rising edge of the trigger signal to match the rising edge of the trigger signal with the AC zero-cross point.

The current sensor 211 measures the electric power supplied to the heater 213 and sends the measurement result to the control unit 110. The temperature sensor 212 measures the temperature of the heater 213 or the surface temperature of the fixing unit 108 and sends the measurement result to the control unit 110. The heater 213 heats the surface of the fixing unit 108 to fix the toner on the sheet.

<B. Trigger signal delay>
FIG. 3 is a diagram showing a first example of a waveform of an input voltage from the AC power supply according to the present embodiment. The example illustrated in FIG. 3 is the input voltage waveform 301 of the power supplied from the AC power supply 214 to the image forming apparatus 100 when the operation mode of the image forming apparatus 100 is “standby (when the fixing heater is off)”. .. The zero-cross point A is a point where the voltage of the input voltage waveform 301 becomes 0V.

FIG. 4 is a diagram showing a first example of the relationship between the trigger signal and the output voltage waveform to the heater according to the present embodiment. The rectified voltage waveform 401 is a waveform obtained by rectifying the input voltage waveform 301. The basic pulse generation threshold B is a threshold for generating a zero-cross signal. The zero-cross signal generation unit 208 generates the zero-cross signal 402 while the voltage of the rectified voltage waveform 401 is lower than the basic pulse generation threshold B.

The trigger signal generation unit 209 generates the trigger signal 403 according to the zero cross point A. Normally, the rising edge 405 of the trigger signal 403 has the same timing as the rising edge 404 of the zero-cross signal 402. In the example shown in FIG. 4, the delay control unit 210 delays the generation timing of the trigger signal 403 from the generation timing of the zero-cross signal 402 by the delay time t1, so that the generation timing of the trigger signal 403 is adjusted to the zero-cross point A. ..

By matching the rising edge 405 of the trigger signal 403 with the zero-cross point A, the electric power supplied to the heater 213 becomes the electric power 407. Since the voltage of the electric power 407 gradually rises from 0 V, it is possible to minimize the influence of rush current and noise on the circuits around the fixing unit 108.

The delay time t1 is calculated as follows. The CPU 110 sets, as the delay time t1, a delay time in which the electric power supplied to the heater 213 between the rising edge 405 and the generation point of the next zero cross point A becomes “a half cycle of the AC output voltage”. The specific procedure will be described below.

First, the CPU 110 generates the trigger signal 403 at the rising edge 404 of the zero-cross signal 402. In this case, the delay time is 0. Then, the CPU 110 obtains the electric power supplied to the heater 213 between the rising edge 405 and the generation point of the next zero cross point A. In this case, the electric power supplied to the heater 213 becomes the electric power 406 from the rising edge 405 to the generation point of the next zero cross point A. Since the power 406 is obviously smaller than the “half cycle of the AC input voltage”, it can be seen that the “rising edge 405” and the “zero cross point A” are offset from each other.

Next, the CPU 110 gradually increases the delay time and obtains the electric power supplied to the heater 213 between the repeated rising edge 405 and the generation point of the next zero cross point A. Then, the CPU 110 stores the delay time at the timing when the electric power supplied to the heater 213 becomes the electric power 407 in the storage unit 202 and uses it as the delay time t1 when the electric power is supplied to the heater from the next time onward. Note that the CPU 110 may use a predetermined threshold value to determine whether the electric power supplied to the heater 213 is smaller than the “half cycle of the AC input voltage”.

As described with reference to FIG. 4, the CPU 110 uses the delay control unit 210 to adjust the rising edge of the trigger signal to the zero-cross point A, thereby suppressing inrush current and noise generated in the circuit. However, the amplitude of the AC input voltage changes due to the change in the operation mode of the image forming apparatus 100. When the amplitude of the AC input voltage changes, the setting of the delay time of the trigger signal once obtained may become unusable. Hereinafter, a problem that occurs when the operation mode is changed will be described based on the examples of FIGS. 5 and 6.

FIG. 5 is a diagram showing a second example of the waveform of the input voltage from the AC power supply according to the present embodiment. In the example shown in FIG. 5, the input voltage waveform 501 of the electric power supplied from the AC power supply 214 to the image forming apparatus 100 when the operation mode of the image forming apparatus 100 is “printing operation (when the fixing heater is lit)”. is there. The zero-cross point A is a point where the voltage of the input voltage waveform 501 becomes 0V. The input voltage waveform 501 has no change in the frequency and the position of the zero-cross point A as compared with the input voltage waveform 301 in the “standby state (when the fixing heater is off)” of the image forming apparatus 100, but the amplitude is significantly small. You can see that it has become.

FIG. 6 is a diagram showing a second example of the relationship between the trigger signal and the output voltage waveform to the heater according to the present embodiment. The rectified voltage waveform 601 is a waveform obtained by rectifying the input voltage waveform 501. The basic pulse generation threshold B is a threshold for generating a zero-cross signal. The zero-cross signal generation unit 208 generates the zero-cross signal 602 while the voltage of the rectified voltage waveform 601 is lower than the basic pulse generation threshold B, as in FIG. 4.

Since the amplitude of the rectified voltage waveform 601 is smaller than the amplitude of the rectified voltage waveform 401 obtained by rectifying the input voltage waveform 301, it obviously takes a long time to fall below the basic pulse generation threshold value B. Therefore, the zero-cross signal 602 based on the rectified voltage waveform 601 has a longer voltage HIGH time than the zero-cross signal 402. This means that the interval from the rising edge 604 to the zero cross point A becomes long.

Even if the CPU 201 delays the trigger signal 603 by using the delay time t1 obtained in FIG. 4, it can be seen that the rising edge 605 of the trigger signal 603 does not coincide with the zero cross point A. In this case, the electric power supplied to the heater 213 becomes like the electric power 606, and there is a possibility that a rush current or a circuit noise is generated when the electric power supply to the heater 213 is started. Therefore, it is understood that the CPU 201 needs to obtain an appropriate delay time of the rising edge of the trigger signal for each operation mode of the image forming apparatus 100.

FIG. 7 is a diagram showing a third example of the relationship between the trigger signal and the output voltage waveform to the heater according to the present embodiment. In the example shown in FIG. 7, the CPU 201 newly adds a delay time t2 of “during printing (when the fixing heater is on)” without using the delay time t1 of “at the time of standby (when the fixing heater is off)”. I'm looking for it.

Since the CPU 201 calculates the delay time t2 in accordance with the rising edge 604 of the zero-cross signal 602, the rising edge 605 of the trigger signal 603 coincides with the zero-cross point A. Further, the electric power supplied to the heater 213 is the electric power 704. The method for obtaining the delay time t2 is the same as the method for obtaining the delay time t1. As described above, the CPU 201 can match the rising edge of the trigger signal with the zero-cross point in any operation mode by obtaining an appropriate delay time of the rising edge of the trigger signal for each operation mode. By doing so, the voltage of the electric power supplied to the heater 213 gradually rises from 0 V, so that the influence of rush current and noise on the circuits around the fixing unit 108 can be minimized.

Hereinafter, a change in the waveform of the input voltage from the AC power supply and a change in the delay time in each operation mode of the image forming apparatus 100 will be described with reference to FIGS. 8 to 11.

FIG. 8 is a diagram showing a third example of the waveform of the input voltage from the AC power supply according to the present embodiment. In the example shown in FIG. 8, an input voltage waveform 801 of the electric power supplied from the AC power supply 214 to the image forming apparatus 100 when the operation mode of the image forming apparatus 100 is “during printing operation (when the fixing heater is off)” is there. The zero-cross point A is a point where the voltage of the input voltage waveform 801 becomes 0V. The input voltage waveform 801 has no change in the frequency and the position of the zero-cross point A, but has a slightly smaller amplitude than the input voltage waveform 301 in the “standby state (when the fixing heater is off)” of the image forming apparatus 100. You can see that

FIG. 9 is a diagram showing a fourth example of the relationship between the trigger signal and the output voltage waveform to the heater according to the present embodiment. In the example shown in FIG. 9, similarly to FIG. 7, the delay time t3 “when the printing operation is performed (when the fixing heater is off)” is newly obtained and used.

The rectified voltage waveform 901 is a waveform obtained by rectifying the input voltage waveform 801. Since the CPU 201 calculates the delay time t3 in accordance with the rising edge 904 of the zero-cross signal 902, the rising edge 905 of the trigger signal 903 coincides with the zero-cross point A. Further, the electric power supplied to the heater 213 is the electric power 906. The method for obtaining the delay time t3 is the same as the method for obtaining the delay time t1.

FIG. 10 is a diagram showing a fourth example of the waveform of the input voltage from the AC power supply according to the present embodiment. The example shown in FIG. 10 is an input voltage waveform 1001 of the electric power supplied from the AC power supply 214 to the image forming apparatus 100 when the operation mode of the image forming apparatus 100 is “standby (when the fixing heater is on)”. .. The zero-cross point A is a point where the voltage of the input voltage waveform 1001 becomes 0V. The input voltage waveform 1001 has no change in the frequency and the position of the zero-cross point A, but has a significantly smaller amplitude than the input voltage waveform 301 of the image forming apparatus 100 in “standby (when the fixing heater is off)”. You can see that

FIG. 11 is a diagram showing a fifth example of the relationship between the trigger signal and the output voltage waveform to the heater according to the present embodiment. In the example shown in FIG. 11, similarly to FIG. 7, the delay time t4 “when the printing operation is performed (when the fixing heater is off)” is newly obtained and used.

The rectified voltage waveform 1101 is a waveform obtained by rectifying the input voltage waveform 1001. Since the CPU 201 calculates the delay time t4 in accordance with the rising edge 1104 of the zero-cross signal 1102, the rising edge 1105 of the trigger signal 1103 coincides with the zero-cross point A. Further, the electric power supplied to the heater 213 is the electric power 1106. The method for obtaining the delay time t4 is the same as the method for obtaining the delay time t1.

<C. Trigger signal delay setting flowchart>
FIG. 12 is an example of a process until the setting of the delay time of the trigger signal according to the present embodiment is obtained. With reference to FIG. 12, a procedure in which the process of obtaining the setting of the delay time of the trigger signal is executed will be described. In a certain aspect, the CPU 201 may read a program for performing the process of FIG. 12 from the storage unit 202 and execute the program.

In step S1210, the CPU 201 acquires a plurality of operation modes from the storage unit 202 and selects an operation mode for measuring the delay time. The operation modes here include, for example, "standby (when the fixing heater is off)", "standby (when the fixing heater is on)", "printing operation (when the fixing heater is off)", and " During printing operation (when the fixing heater is turned on)” and the like.

In step S1220, CPU 201 operates image forming apparatus 100 in the operation mode selected in step S1210. The CPU 201 also uses the zero-cross signal generation unit 208 to generate a zero-cross signal. Then, the CPU 201 uses the trigger signal generation unit 209 to generate a trigger signal (basic trigger signal) at the same timing as the rising edge of the zero-cross signal.

In step S1230, the CPU 201 uses the delay control unit 210 to delay the basic trigger signal by a predetermined time. The predetermined time here is, for example, several milliseconds or several microseconds, but is not limited thereto.

In step S1240, the CPU 201 uses the current sensor 211 to measure the electric power supplied to the heater 213 from the rising edge of the trigger signal to the next zero cross point. The CPU 201 determines whether the measured power exceeds a predetermined threshold value. Whether or not the measured power here exceeds a predetermined threshold means whether or not the rising edge of the trigger signal in the description of FIG. 4 matches the zero cross point.

When CPU 201 determines that the measured power exceeds the predetermined threshold value (YES in step S1240), control proceeds to step S1250. If not (NO in step S1240), CPU 201 shifts the control to step S1230, further increases the delay time, and executes the process of step S1230. It should be noted that the predetermined threshold here may be any value that can determine that the power measured by the current sensor 211 is the power from a certain zero-cross point to the next zero-cross point.

In step S1250, the CPU 201 stores the delay time obtained in step S1240 in the storage unit 202 as the delay setting of the rising edge of the trigger signal in the current operation mode. When operating the image forming apparatus 100 again in the current operation mode, the CPU 201 reads the delay setting of the rising edge of the trigger signal stored in the storage unit 202 and uses it for the control as the heater control unit 207.

In step S1260, the CPU 201 determines whether or not the delay time of the trigger signal has been measured in all the operation modes registered in the storage unit 202 in advance. CPU201 complete|finishes a process, when it determines with having measured the delay time of a trigger signal in all the operation modes previously registered into the memory|storage part 202 (it is YES at step S1260). If not (NO in step S1260), CPU 201 shifts the control to step S1210, switches the operation mode of image forming apparatus 100 to another operation mode, and repeats the measurement of the delay time of the trigger signal.

The processing of FIG. 12 may be executed by the CPU 201 at any timing. In a certain aspect, the CPU 201 may execute all or part of the processing in FIG. 12 at the timing of acquiring an instruction from the user via the UI 203, or may periodically execute all or part of the processing in FIG. You may do it. Further, the CPU 201 may execute all or part of the processing of FIG. 12 at set time intervals by using the built-in timer function.

Further, in a certain aspect, the CPU 201 may execute all or a part of the processing of FIG. 12 each time a print operation is performed, each time the main power is turned on, during standby time, and each time when returning from sleep. Further, in a certain aspect, the CPU 201 may perform all or a part of the processing in FIG. 12 immediately after the heater 213 is started to be turned on and after a predetermined time has elapsed since the heater 213 was turned on. Further, in a certain aspect, the CPU 201 may perform all or part of the processing in FIG. 12 after a predetermined time has elapsed after turning off the heater 213.

Further, in a certain aspect, the CPU 201 may transmit the delay setting of the trigger signal acquired in FIG. 12 to the external server via the communication unit 205. Further, the CPU 201 may acquire the delay setting of the trigger signal from the external server via the communication unit 205 as needed.

Further, in a certain aspect, the CPU 201 may store the delay setting of the trigger signal in the first operation mode in the storage unit 202 as a reference. In that case, the CPU 201 stores, in the storage unit 202, the difference information regarding the delay setting of the trigger signal of the other operation mode, with respect to the delay setting of the first operation mode. Further, the CPU 201 may use the above-described configurations and processing in combination.

As described above, the CPU 201 obtains an appropriate delay time of the trigger signal for each operation mode (by detecting the position of the zero-cross point based on the zero-cross signal), which operation mode Also in the above, the rising edge of the trigger signal can be aligned with the zero-cross point.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include all modifications within the meaning and range equivalent to the scope of the claims.

100 image forming apparatus, 101 manual feed tray, 102 paper feed cassette, 103 paper feed roller, 104 registration roller, 105 imaging unit, 106 intermediate transfer belt, 107 transfer roller, 108 fixing section, 109 discharge tray, 110 control section, 200 circuits , 201 CPU, 202 storage unit, 203 UI, 204 display unit, 205 communication unit, 206 power supply unit, 207 heater control unit, 208 zero cross signal generation unit, 209 trigger signal generation unit, 210 delay control unit, 211 current sensor, 212 Temperature sensor, 213 heater, 214 AC power supply, 301, 501, 801, 1001 input voltage waveform, 401, 601, 901, 1101 rectified voltage waveform, 402, 602, 902, 1102 zero cross signal, 403, 603, 903, 1103 trigger Signal, 404, 405, 604, 605, 904, 905, 1104, 1105 Rising edge, 406, 407, 606, 704, 906, 1106 Power.

Claims (20)

An image forming apparatus,
A power supply unit that supplies alternating current from an alternating current power supply to the image forming apparatus;
A fixing unit that has a built-in heater and fixes toner to paper,
A zero-cross signal generator that generates a zero-cross signal based on the alternating current,
Based on the rising edge of the zero-cross signal, a trigger signal generation unit that generates a trigger signal,
A delay control unit for delaying the rising of the trigger signal,
A control unit for controlling the image forming apparatus,
The zero-cross signal generation unit generates the zero-cross signal in each operation mode of the image forming apparatus,
The trigger signal generation unit generates the trigger signal based on the zero-cross signal of each operation mode,
The delay control unit delays the rising of the trigger signal in each of the operation modes,
The image forming apparatus, wherein the control unit supplies the alternating current to the fixing unit based on a delay in rising of the trigger signal in each of the operation modes. Further comprising a current measuring unit for measuring a current supplied to the fixing unit,
Delaying the trigger signal
The current measuring unit measures a current supplied to the fixing unit,
The control unit, based on the measured current, the amount of electric power supplied to the fixing unit between the start of the supply of the AC to the fixing unit and the occurrence of the next zero-cross point of the AC. To calculate
The image forming apparatus according to claim 1, wherein the delay control unit delays the trigger signal based on the power amount and matches a rising edge of the trigger signal with a generation timing of the zero-cross point. Further comprising a storage unit for storing the setting of the delay of the trigger signal in each of the operation modes,
The image forming apparatus according to claim 1, wherein the control unit stores, in the storage unit, a setting of a delay in rising of the trigger signal in each of the operation modes. The image forming apparatus according to claim 3, wherein the control unit obtains a setting of a rising delay of the trigger signal in each of the operation modes and stores the setting in the storage unit at a constant cycle. The image forming apparatus according to claim 3, wherein the control unit obtains a setting of a rising delay of the trigger signal in each of the operation modes and stores the setting in the storage unit for each printing process. The control unit obtains a setting of a delay in rising of the trigger signal in each of the operation modes and stores the setting in the storage unit every time the main power of the image forming apparatus is turned on. The image forming apparatus according to item 1. The image forming apparatus according to claim 3, wherein the control unit obtains a setting of a delay of a rising edge of the trigger signal in each of the operation modes and stores the setting in the storage unit each time the device returns from sleep. .. The control unit includes a timer function, and obtains a delay setting for the rising edge of the trigger signal in each of the operation modes and stores the delay setting in the storage unit for each constant count by the timer function. 2. The image forming apparatus according to item 1. The control unit obtains the setting of the delay of the rising edge of the trigger signal in each of the operation modes and stores the setting in the storage unit immediately after the heater starts lighting and after a predetermined time elapses from the start of the heater lighting. The image forming apparatus according to any one of claims 3 to 8. 10. The controller according to claim 3, wherein after a lapse of a predetermined time from turning off the heater, the controller obtains a setting for a delay in rising of the trigger signal in each of the operation modes and stores the setting in the storage. The image forming apparatus according to item 1. Further comprising a communication unit for communicating with an external device,
The control unit is
Via the communication unit, the setting of the rising delay of the trigger signal is transmitted to an external server,
The image forming apparatus according to claim 3, wherein the setting of the rising delay of the trigger signal is acquired from the external server via the communication unit. The control unit is
Save the setting of the rising delay of the trigger signal in the first operation mode as a reference in the storage unit,
The image forming apparatus according to claim 3, wherein the setting of the rising delay of the trigger signal in another operation mode is stored in the storage unit as a difference from the reference. 4. The control unit obtains, from the storage unit, a setting of a rising delay of the trigger signal according to a scheduled operation state of the image forming apparatus, and uses the setting for delay control of a rising edge of the trigger signal. 13. The image forming apparatus according to any one of 1 to 12. The image forming apparatus according to claim 13, wherein the scheduled operation state includes a standby state and a print state. A method for controlling an image forming apparatus, comprising:
In each operation mode of the image forming apparatus, a step of generating a zero-cross signal based on alternating current supplied from an alternating current power supply,
Generating a trigger signal based on the rising edge of the zero-cross signal in each of the operation modes;
Delaying the rising edge of the trigger signal in each of the operating modes;
Supplying the alternating current to a fixing unit including a heater based on a delay in rising of the trigger signal in each of the operation modes. Delaying the trigger signal comprises:
Measuring a current supplied to the fixing unit,
Calculating the amount of electric power supplied to the fixing unit from the start of the supply of the alternating current to the fixing unit to the occurrence of the next zero-cross point of the alternating current, based on the measured current. ,
16. The method according to claim 15, further comprising the step of delaying the trigger signal based on the power amount so that a rising edge of the trigger signal coincides with a generation timing of the zero-cross point. 17. The method of claim 15 or 16, further comprising the step of storing a rising delay setting of the trigger signal for each of the operating modes. The method according to any one of claims 15 to 17, wherein the setting of the rising delay of the trigger signal in each of the operation modes is obtained and stored at a constant cycle. The method according to any one of claims 15 to 18, wherein a setting of a delay in rising of the trigger signal in each of the operation modes is obtained and stored for each printing process. The method according to any one of claims 15 to 19, wherein the setting of the rising delay of the trigger signal in each of the operation modes is obtained and stored each time the main power of the image forming apparatus is turned on.

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