JP4919541B2 - Power supply method, power supply device, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply method, a power supply apparatus, and an image forming apparatus that receive power from an AC power supply and supply adjusted power to a load. Specifically, for example, in an image forming apparatus such as a printer, a copier, a facsimile, or an original image reading apparatus, the power from an AC power source is supplied to a relatively high power consumption load, and control is performed. The present invention relates to a composite power supply that simultaneously supplies power to a load with relatively low power consumption such as a system circuit or an electronic device.
[0002]
[Prior art]
For example, in a power supply device that supplies power to several types of loads having different operating voltages, such as a power supply device of an image forming apparatus, a lower limit voltage when supply power fluctuates due to voltage fluctuation of an AC power supply, and the like. Each load current value in the apparatus is set so that the input current to the apparatus is less than or equal to a predetermined upper limit value under any of the conditions where the option is connected and the power consumption in the apparatus is maximized.
[0003]
For this reason, when the AC power supply is at a standard voltage or when no option is connected to the device, the input current to the device is much lower than a predetermined value. This is a usage with a so-called margin.
[0004]
For DC loads, the input AC voltage is rectified and smoothed, and if necessary, the voltage value is adjusted (transformed) by a DC / DC converter and then supplied directly, or pulsed by PWM control via a switching circuit. . In the case of energizing the AC load, the energization power to the AC load is controlled by conduction phase control using a triac.
[0005]
When there is a rectifying and smoothing circuit that converts input AC voltage to DC voltage, if the load current is low, the capacitor of the rectifying and smoothing circuit is charged with the input AC current only near the peak value of the input AC voltage. Collapses from the sine wave to generate a harmonic component, which not only lowers the power factor of the AC power (increases power loss) but also causes power supply noise. Even in the AC energization based on the conduction phase control using the triac, if the required load current is low, the conduction (on trigger) phase angle increases and the collapse of the input AC current waveform increases.
[0006]
[Problems to be solved by the invention]
The first object of the present invention is to reduce the waveform distortion of the AC input current. In addition, the second object is to make the power supply to the load suitable when the power supply environment for one load is favorable, such as when the voltage of the AC power supply is high or the number of simultaneous power supply loads is small. The third object is to reduce the waveform distortion of the AC input current of the image forming apparatus, and image formation is possible when the image forming apparatus returns from the sleep mode for energy saving to the operation mode for image formation or preparation. The fourth purpose is to shorten the delay time until the image becomes, specifically, the temperature of the fixing heater of the image forming apparatus is increased as quickly as possible while reducing the waveform distortion of the AC input current. The fifth object is to increase the temperature stability.
[0007]
[Means for Solving the Problems]
(1) In a method of receiving AC power and supplying adjusted power to a load (123C),
AC input instantaneous voltage (V0) , Instantaneous current value (I0) And peak voltage Detect value (Vp)
Above Peak voltage For value (Vp) AC input is rated voltage (Vs) And rated current (Is) The peak voltage that is the peak voltage value at Ratio of reference value (Vps) (Kv ) And the rated voltage Against Said rating Current ratio (Ki) The To the instantaneous voltage value (VO) Multiplied Instantaneous current Goal Generate a value (TIO)
The instantaneous current value (IO) of AC input is the instantaneous current Goal A power supply method characterized by controlling power supply to a load (123C) so as to match a value (TIO).
[0008]
In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the corresponding matter of the Example shown in drawing and mentioned later in parenthesis was added for reference. The same applies to the following.
[0009]
here, Peak voltage when AC input is rated voltage Vs and rated current Is value The peak voltage Standard Value V When expressed as ps, the actual AC instantaneous voltage is V0, peak When the value is Vp, the alternating instantaneous current I0 is assumed to be the next instantaneous current. Goal Value TI0,
TI0 = (Is / Vs) · V0 · (Vps / Vp) (1)
= Ki ・ Vps ・ V0 / Vp (2)
= K ・ V0 / Vp (3)
= Ki / Kv / V0 (4)
Ki = Is / Vs (5)
K = Ki ・ Vps (6)
Kv = Vps / Vp (7)
If adjusted to match the AC instantaneous current I0 is Rated current Since it coincides with the value Is and is proportional to the AC instantaneous voltage V0, if the AC instantaneous voltage V0 indicates a change in sine wave, the AC instantaneous current I0 indicates a change in sine wave.
[0010]
In the present invention, the AC instantaneous current I0 is the instantaneous current according to the above equation (4). Goal Since the power supplied to the load (123C) is controlled so that the value TI0 = Ki · Kv · V0, the waveform distortion of the AC input current is reduced. AC power supply peak Voltage value When the power supply environment for one load (123C) is favorable, such as when (Vp) is high or the number of simultaneous power supply loads is small, the power supply current value for the load (123C) automatically increases. For example, when the load is a fixing heater (123C), the temperature rises quickly, and the delay time until image formation is possible when returning from the sleep mode for energy saving to the operation mode for image formation or preparation is short. In addition, during the constant temperature control, the temperature rise during energization is fast, so that the stability of the fixing temperature is increased.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(2) Peak following time series change of instantaneous voltage value (VO) of AC input Voltage Value (Vp) put out The power feeding method according to (1) above.
According to this, with a relatively simple process, Peak voltage The value (Vp) can be determined.
[0012]
(3) In the power supply device (80) that receives AC power and supplies the adjusted power to the load (123C),
Means for detecting instantaneous voltage value (V0) of AC input (R2,85);
Means (ISEN0, 85) for detecting the instantaneous current value (I0) of the AC input;
AC input voltage Peak voltage Means (R2,85) for detecting the value (Vp);
Above Peak voltage For value (Vp) AC input is rated voltage (Vs) And rated current (Is) The peak voltage that is the peak voltage value at Ratio of reference value (Vps) (Kv ) And the rated voltage Against Said rating Current ratio (Ki) The To the instantaneous voltage value (VO) Multiplied Instantaneous current Goal Means (85) for generating a value (TIO); and
The instantaneous current value (IO) of the AC input is the instantaneous current. Goal Power supply control means (85) for controlling the power supplied to the load (123C) so as to match the value (TIO);
A power supply apparatus comprising:
[0013]
According to this, the AC instantaneous current I0 is the instantaneous current according to the above equation (4). Goal Since the power supply control means (85) controls the power supply to the load (123C) so that the value (TI0) is obtained, the waveform distortion of the AC input current is reduced. AC power supply peak Voltage value When the power supply environment for one load (123C) is favorable, such as when (Vp) is high or the number of simultaneous power supply loads is small, the power supply current value for the load (123C) automatically increases. For example, when the load is a fixing heater (123C), the temperature rises quickly, and the delay time until image formation is possible when returning from the sleep mode for energy saving to the operation mode for image formation or preparation is short. In addition, during the constant temperature control, the temperature rise during energization is fast, so that the stability of the fixing temperature is increased.
[0014]
(4) of the AC input voltage Peak voltage The means (R2, 85) for detecting the value (Vp) detects the peak voltages of the positive and negative polarities during one period (T) of the AC input, and calculates the average value thereof. Peak voltage Value (Vp); The power supply device according to (3) above. According to this, the representative value (Vp) can be detected with high accuracy even in an environment where the power supply situation is not good, such as private power generation, in which the fluctuation of the AC power supply is large.
[0015]
(5) A visible image forming apparatus (100) having means (20) and control means (50, 60) for inputting instructions from an operator, and forming a visible image corresponding to an image signal on a sheet; An energization adjusting means (Q) for adjusting the power supplied to the electrical load of the forming apparatus (100); and the power supply apparatus according to (3) above,
The power supply control means (85) of the power supply device supplies a power supply control signal (PWM3) to the power supply adjustment means (Q), and the instantaneous current value (IO) of the AC input is the instantaneous current. Goal Change to match the value (TIO);
Image forming apparatus.
[0016]
According to this, the function and effect described in the above (3) can be similarly obtained in the image forming apparatus.
[0017]
(6) The power supply control signal is a PWM pulse (PWM3), and the energization adjusting means to which it is supplied is a switching means (Q) for energizing the fixing heater (123C);
The power supply control means (85) outputs the power supply control signal to the instantaneous current. Goal Corresponding to the deviation (TIO-IO) of the instantaneous current value (IO) with respect to the value (TIO), the deviation is reduced and the temperature sensor (TH) of the visible image forming apparatus (100) is changed. When the fixing temperature (THM) detected by the printer is below the set value (180 ° C), the duty of the PWM pulse (PWM3) is changed to one that reduces the deviation (TI0-I0), and the fixing temperature (THM) When the set value (180 ° C) is exceeded, the energizing current value of the fixing heater (123C) is limited to a low value including zero;
The image forming apparatus according to (5) above.
[0018]
According to this, the AC instantaneous current I0 is the instantaneous current according to the above equation (4). Goal Since the PWM pulse (PWM3) given to the switching means (Q) by the power supply control means (85) is changed so that the value (TI0) is obtained, the waveform distortion of the AC input current of the image forming apparatus is reduced. The number of simultaneous power supply loads, such as when the AC power supply voltage (Vp) is high, immediately after the image forming apparatus is turned on, or when warming up when returning from the sleep mode for energy saving to the operation mode for image formation or preparation When there is little, the current supplied to the fixing heater (123C) is high, the temperature rises quickly, and the warm-up time is short. Become .
[0019]
When the fixing temperature (THM) reaches a set value (180 ° C. or lower, such as 170 ° C.), image formation can be started. When power is supplied to many other loads for image formation, the AC input current value increases, so the power supply current value to the fixing heater (123C) automatically decreases. When the number of energized loads decreases due to the end of image formation or the like, a high current flows through the fixing heater (123C) when the fixing temperature (THM) is lower than the set value (180 ° C.). In this way, rational distribution of the current value to the fixing heater (123C) and other loads is automatically performed.
[0020]
(7) Instantaneous current Goal The means (85) for generating the value (TIO) presets the target value of the input current at each voltage value within the half cycle of the AC power source, and detects the detected peak voltage. value Vp Rupi Voltage Standard value According to the ratio Kv = Vps / Vp with Vps, the target value of the input current I0 at each voltage value V0 within the half cycle of the AC power supply is corrected (TI0 = Ki · Kv · V0). Power supply.
[0021]
According to this, even in an environment where the power supply situation is not good, it is possible to accurately control the current input to the power supply device.
[0022]
(8) The means (R2,85) for detecting the instantaneous voltage value (VO) and the means (ISEN0,85) for detecting the instantaneous current value (IO) are respectively connected to the voltage V0 and the input current I0 input from the AC power source. The power supply control means (85, PWM3, Q) performs PWM control of the load current so that the input current I0 of the AC power supply becomes equal to the target value TI0; 3) Power supply device.
[0023]
According to this, the waveform of the input current can be made sinusoidal, and the AC power supply can be used efficiently. Harmonic current can be reduced.
[0024]
(9) The power supply control means (85, PWM3, Q) performs PWM control on the load current supplied to the fixing device (123C) in the device (100) so that the input current I0 becomes equal to the target value TI0 (PWM3 In addition, when the temperature (THM) of the fixing device (123C) is detected and the detected temperature is higher than a predetermined temperature (180 ° C.), the fixing device (123C) has priority over the control of the input current I0. ) To limit the load current (PWM3 = 0); the image forming apparatus of (5) above.
[0025]
According to this, it is possible to shorten the rise time from the standby state of the apparatus (100) until image formation is possible, and to further improve the stability of the fixing temperature.
[0026]
(10) The image forming apparatus according to (9), wherein an energization duty to the fixing device (123C) by PWM control (PWM3) is between 0% and 100%.
[0027]
According to this, the input current I0 to the apparatus (100) can be finely controlled, and an energy-saving image forming apparatus can be provided.
[0028]
Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
[0029]
【Example】
FIG. 1 shows the external appearance of a multifunction copying machine incorporating a power supply apparatus according to an embodiment of the present invention. This multi-function copier is roughly an automatic document feeder [ADF] 30, an operation unit 20, a color scanner 10, a color printer 100, a relay unit 32, a stapler and a large amount of imaged paper. The stacker includes a finisher 34 with a shift tray, a duplex reversing unit 33, a paper feed bank 35, a large-capacity paper feed tray 36, and a 1-bin paper discharge tray 31.
[0030]
FIG. 2 shows the configuration of the color printer 100. Reference numeral 101 denotes a flexible photosensitive belt serving as a belt-shaped image carrier. The photosensitive belt 101 is installed between the rotating rollers 102 and 3, and is rotated in the direction indicated by an arrow A (clockwise) in FIG. Direction). In the figure, reference numeral 104 denotes a charging charger that uniformly charges the surface of the photosensitive belt 101, and reference numeral 105 denotes a laser exposure apparatus that is an image writing unit. In the figure, 106 is a color developing device, 106a is magenta, 106b is cyan, 106c is yellow, and 106d is a black developing unit.
[0031]
Further, reference numeral 109 in the figure denotes an intermediate transfer belt as an image carrier and an intermediate transfer medium. The intermediate transfer belt 109 is installed on a rotating roller 110-112, and is driven in the direction indicated by an arrow B in FIG. (Counterclockwise) The photosensitive belt 101 and the intermediate transfer belt 109 are in contact with each other by a symbolless rotating roller portion of the photosensitive belt 101. On the intermediate transfer belt 109 side of the contact portion, a conductive bias roller 113 is in contact with the back surface of the intermediate transfer belt 110 under predetermined conditions.
[0032]
The photosensitive belt 101 is uniformly charged by a charging charger 104 and then exposed by scanning with a laser beam modulated by an image recording signal by a laser exposure device 105. As a result, an electrostatic latent image is formed on the photosensitive belt 101. Here, the image recording signal for modulating the laser beam is for each color (single color) obtained by decomposing a desired full color image into magenta, cyan, yellow, and black (Bk) color information. The formation of the electrostatic latent image and the development by the color in the developing devices 106a to 106d are repeated for the number of colors (for example, magenta, cyan, yellow, and black, a total of four times). The developed images (toner images) appearing by development are transferred onto the intermediate transfer belt 9 in a superimposed manner.
[0033]
That is, each single-color image (toner image) formed on the photosensitive belt 1 rotating in the direction of arrow A in the figure is synchronized with the photosensitive belt 101 on the intermediate transfer belt 109 rotating in the direction of arrow B in the figure. , Magenta, cyan, yellow, and black are sequentially superimposed and transferred by a predetermined transfer bias applied to the bias roller 113. The magenta, cyan, yellow, and black images superimposed on the intermediate transfer belt 109 are fed from the paper feed cassette 116a of the paper feed tray 116 to the paper feed roller 117, the transport roller pair 118a and 118b, and the registration roller pair 119a and 119b. After that, the images are collectively transferred onto the transfer paper conveyed to the transfer roller 114. After the transfer is completed, the toner image on the transfer paper is fixed (heat-pressed) on the transfer paper by the fixing device 120. As a result, a full-color image is completed, and the transfer paper is discharged to the paper discharge stack section 122 through the paper discharge roller pair 121a and 121b.
[0034]
In the figure, reference numeral 107 denotes a cleaning blade that always contacts the photosensitive belt 101 and wipes off the toner on the photosensitive belt 101. Reference numeral 115 denotes a cleaning device for the intermediate transfer belt 109, and the cleaning brush for the cleaning device 115. 115a is held at a position separated from the surface of the intermediate transfer belt 110 during the image forming operation, and a formed image is transferred onto the transfer paper described above and then brought into contact with the surface of the intermediate transfer belt 110.
[0035]
Further, the photosensitive belt 101, the charging charger 104, the intermediate transfer belt 109, and the cleaning devices 107 and 115 are integrally assembled into a process cartridge to form a unit.
[0036]
Reference numeral 108 denotes a toner adhesion amount sensor for detecting the toner adhesion amount on the photosensitive belt 101. The toner adhesion amount sensor 108 used this time generates and outputs a voltage, that is, a detection signal corresponding to the amount of light received by the photodiode, in which the light emitting portion is an infrared light emitting diode and the diffuse reflection light receiving portion is a photodiode. A toner concentration sensor for measuring the amount of diffusely reflected light.
[0037]
Inside the fixing roller of the fixing device 120 is a fixing heater (halogen lamp) 123C. The third power circuit PC3 (FIG. 4) is energized to the fixing heater 123C, whereby the fixing heater 123C generates heat and infrared rays. And the fixing roller is heated.
[0038]
FIG. 3 shows an outline of the electric system of the copying machine shown in FIG. One MPU 51 on the main control plate 50 and one CPU 12 on the scanner control plate 11 are used as a copier mechanical control unit, that is, a main part of image reading and image forming process control. The MPU 51 performs image-related sequence and fixing control and system-related control, and the CPU 12 performs scanner-related control. The MPU 51 and the CPU 12 are connected by an image data interface and a serial interface.
[0039]
In FIG. 3, 20 is an operation unit, 70 is an I / O control board equipped with an input / output electric circuit, 92 is an LD control board for controlling laser light for image exposure, 41 is a paper feed control board, 13 is A reading control board on which a CCD is mounted, 80 is a DC power supply, and 90 is a motherboard.
[0040]
A printer controller (board) 60 controls a printer function for printing a document of a host such as a personal computer or a word processor, and a combined operation mode of a copy, facsimile, and printer. Reference numeral 91 denotes an application expansion unit for realizing a composite function, which is a facsimile control unit equipped with a FAX function. Reference numeral 80 denotes a DC power source / AC control board.
[0041]
FIG. 4 shows an outline of a power supply circuit on the DC power supply device 80 and an outline of an electric load fed by the power supply circuit. The DC power supply 80 includes a circuit breaker CB, an arrester AR, and a filter 81 that removes AC AC noise, an AC current detection circuit ISEN0 that detects an AC AC input current instantaneous value, and a main power switch SWap (AC input switch). ) Is fed (closed) to rectify and smooth an AC voltage, and first and second power supply circuits (DC / DC converters) that are supplied with output DC and generate DC voltages 5 V and 24 V, respectively. ) There is a third power supply circuit PC3 that converts AC voltage to 100V DC, which is fed by closing (ON) of PC1, PC2 and power relay RA2. The third power supply circuit PC3 includes a rectifying / smoothing circuit that rectifies and smoothes an AC voltage, and applies a DC voltage of 100 V, which is an output DC, to the fixing heater 123C via the switching transistor Q (FIG. 5).
[0042]
The digital controller 85 gives the PWM pulses PWM1 to PWM3 respectively to the conduction of the switching FETs 1 and 2 (FIG. 5) of the first and second power supply circuits PC1 and PC2 and the switching transistor Q of the third power supply circuit PC3. ,Control. In this embodiment, a digital signal processor DSP is used for the digital controller 85. Hereinafter, it is expressed as a DSP.
[0043]
When the main power switch SWap is switched from open (OFF) to closed (ON) and the AC power supply AC is applied and a DC voltage appears in the rectifying / smoothing circuit 82, the switch circuit (SW) 83 is thereby turned on and the battery 84 is turned on. Is applied to the DSP 85. When the DSP 85 energizes the relay driver, the control relay RA3 is turned on to supply power to the power relay RA2, and the power relay RA2 is turned on to supply an AC voltage to the third power supply circuit PC3.
[0044]
First and second power supply circuits PC1 and PC2 of 5V and 24V are connected to loads such as a scanner motor and an ADF (automatic document feeder), and supply necessary voltages to the loads. The third power supply circuit PC3 that outputs a 100V DC voltage outputs 100V to the fixing heater 123C.
[0045]
The DSP 85 communicates with the printer controller 60 mounted on the mother board 90 by UART (Universal Asynchronous Receiver Transmitter: serial communication). Although not shown, the printer controller 60 is a computer system including a CPU, a nonvolatile memory, a ROM, a RAM, and an image memory.
[0046]
FIG. 5 shows the configuration of the switch circuit 83 shown in FIG. 4, the first power supply circuit PC1 generating 5V, and the third power supply circuit PC3 generating 100V. A 100 V commercial AC voltage is applied to the rectifying and smoothing circuit 82 through the noise filter 81 when the main power switch SWap is turned on.
[0047]
The noise filter 81 is an input filter that blocks high-frequency noise of the 100V commercial AC line from entering the switching power supply, that is, the power supply circuits PC1 to PC3, and prevents high-frequency noise generated by the switching power supply from leaking to the commercial AC line. It is. The AC voltage is applied through this input filter 81 to a rectifying / smoothing circuit 82 including a full-wave rectifying diode bridge and a smoothing capacitor and a full-wave rectifying circuit of the third power supply circuit PC3.
[0048]
The output voltage of the rectifying / smoothing circuit 82 is also applied to a starting circuit composed of a resistor and a relay RA1. When the output voltage of the rectifying / smoothing circuit 82 is applied, the relay contact of the relay RA1 between the diode D4 of the switch circuit (SW) 83 and the operating voltage input terminal Vcc of the DSP 85 is closed by the relay contact RA1. Since the diode D4 is connected to the battery 84, the battery voltage is applied to the DSP 85, whereby the DSP 85 is activated and outputs the first PWM pulse PWM1 to the switching driver DRIVE1 of the first power supply circuit PC1 that generates 5V.
[0049]
As a result, the first power supply circuit PC1 that generates 5V enters an operating state and generates a 5V DC voltage. The output DC voltage of the rectifying / smoothing circuit 82 is applied to the primary winding of the transformer TR1 in the first power supply circuit PC1. When the switching element FET1 is turned on, a current flows from the rectifying / smoothing circuit 82 to the primary side ground via the primary winding, the switching element FET1 and the current value detection circuit ISEN1.
[0050]
The switching driver DRIV1 is connected to a PWM output port that outputs a first PWM pulse PWM1 that is a switching ON / OFF signal of the DSP 85. The primary side switching circuit is constituted by DRIV1, transformer TR1 and switching element FET1, and the output voltage of rectifying and smoothing circuit 82 is chopped by switching in response to the PWM pulse, and the primary winding of transformer TR1 is pulse-energized.
[0051]
On the secondary side of the transformer TR1, there is an output circuit that converts a pulse voltage induced in the secondary winding into a direct current and outputs it. The output circuit includes diodes D1 and D2, a choke coil CH1, an output voltage detection circuit VSEN1, and a smoothing capacitor.
[0052]
The same is true for the configuration and operation of the second power supply circuit PC2 that generates 24V, and the control operation of the DSP 85 for them (giving PWM2). However, in the second power supply circuit PC2 that generates 24V, in which the power capacity of the generation circuit is large, a plurality of switching elements FET are used in parallel connection.
[0053]
The third power supply circuit PC3 that generates 100V DC that energizes the fixing heater 123C includes a current detection circuit ISEN3 and a voltage detection circuit VSEN3 that detect a load current value and an output voltage, and detects a fixing temperature around the fixing heater 123C. The thermistor TH is connected.
[0054]
The CPU and MPU that monitor inputs even in the energy saving standby mode and the circuit that generates an external input signal in the energy saving standby mode of the printer controller 60, the I / O control board 70, and the main control board 50 include a first power supply circuit PC1. Supply power.
[0055]
FIG. 6 shows the configuration of the DSP 85. In this example, an event manager is used for the PWM pulse generator 85e. This includes a plurality of PWM pulse output ports, and the CPU 85a loads the data defining the PWM pulse and the pulse duty addressed to each output port into a pulse generation control register in the PWM pulse generator 85e. When this load is present, the PWM pulse generator 85e generates a PWM pulse defined by the register data and outputs it from the PWM pulse output port. In this embodiment, from the three PWM pulse output ports PWM1, PWM2 and PWM3 to the switching drivers DRIVE1, DRIVE2 and DRIVE3 of the first power supply circuit PC1, second power supply circuit PC2 and third power supply circuit PC3, each PWM pulse PWM1, PWM2 and PWM3 are output. The data defining the period and duty (energization duty) of each PWM pulse is set by the CPU 85a in the pulse generator 85e.
[0056]
The input channel No. of the A / D converter 85i in the DSP 85 is set. Each of 0 to 8 includes the output voltage V1 and output current I1 of the first power supply circuit PC1, the output voltage V2 and output current I2 of the second power supply circuit PC2, and the output voltage V3 and output current I3 of the third power supply circuit PC3. A voltage (analog signal) representing each of the AC input instantaneous current I0, the AC input instantaneous voltage V0, and the fixing temperature HM, that is, a detection signal is applied.
[0057]
The A / D converter 85i converts the detection signal (feedback signal) applied to the designated input channel into digital data under the control (instruction) of the CPU 85a via the interface 85h and outputs its own output. Latch in register and generate conversion complete signal.
[0058]
In response to the conversion completion signal, the CPU 85a reads digital data (A / D conversion data), that is, detection data (feedback data), and sets the output voltages of the first and second power supply circuits PC1 and PC2 to the set voltage (5V, 24V) to calculate PWM1, 2 pulse duty, write the data defining it to the pulse generator 85e, make the AC input current waveform similar to the AC input voltage waveform, and make the AC input current constant current To calculate the PWM3 pulse duty to the third power supply circuit PC3, write the data defining it to the pulse generator 85e, and output voltage abnormality and output of the first to third power supply circuits PC1 to PC3 Checks for current abnormality and stops PWM pulse output when there is abnormality.
[0059]
A program for performing the above-described operation or processing of the CPU 85a is written in the EEPROM 7b. The RAM 85c is used for temporary storage or storage of data.
[0060]
FIG. 7A shows a start-up operation of the power supply device 80 when the main power switch SWap is switched from open (off) to closed (on). When the main power switch SWap is turned on (step 1), a current flows through the relay RA1 of the starting circuit, and the contact piece RA1 is turned on (step 2). In the following description, the word “step” is omitted in parentheses, and step no. Write numbers only. When the relay contact RA1 is turned on, a voltage is supplied from the battery 84 to the power supply terminal Vcc of the DSP 85 via the diode D4, and the DSP 85 is activated (3). When the DSP 85 is activated, the DSP 85 activates the first power supply circuit PC1 that is a DC / DC converter that generates a 5V DC voltage. That is, the PWM control for adjusting the duty of the first PWM pulse so that it becomes the target value 5V with reference to the output of the first PWM pulse PWM1 and its output voltage ("5V in FIG. 8"). "Voltage control" (72) and "5V current abnormality control" (74)) are started (4). When the first power supply circuit PC1 is activated, the 5V direct current is supplied to the printer controller 60 of the motherboard 90 and the MPU 51 (FIG. 3) of the main control board 50 and to the circuit unit required for state monitoring and control by them, and engine control means (CPU and MPU 51 of controller 60) are activated (5). When the controller 60 completes the start-up, the DSP 85 instructs the DSP 85 to turn on the power relay RA2 (energization of the relay coil of the control relay RA3), and the DSP 85 activates the relay driver accordingly, thereby turning on the control relay RA3. As a result, the power relay RA2 is turned on (6).
[0061]
Next, the controller 60 instructs the DSP 85 to heat up the fixing, and in response to this, the DSP 85 starts the output of the PWM 3 that switches the output transistor Q of the third power supply circuit PC5 for the fixing heater (7). This is started at an earlier timing than the second power supply circuit PC2 that supplies power to the power system because the heat capacity of the fixing roller incorporating the fixing heater 123C is large and it takes time to rise in temperature. When the temperature of the fixing heater 123C reaches a predetermined value (reload temperature: 170 ° C.), the start-up process is terminated and the temperature control is switched to the fixing target temperature (180 ° C.). When this switching is finished, the second power supply circuit PC2 which is a DC / DC converter is started (8). When the output voltages of these power supply circuits PC1, PC2 and PC3 all exceed a predetermined value, the DSP 85 notifies the power supply ready to the CPU of the controller 60 by UART communication, and the CPU of the controller 60 responds to this via the MPU 51. Then, homing is performed (9).
[0062]
In this homing, the CPU of the printer controller 60 instructs each part of the copying machine to execute a homing operation for adjusting a homing position such as a scanner position and a FIN (finisher) tray position.
[0063]
When the homing operation is completed, the CPU of the printer controller 60 thereafter performs normal processing of the copying machine. As is well known in this normal processing, the CPU of the printer controller 60 sets the power saving mode when there is no copy or print instruction and there is no operation on the operation unit 20 and the set time has elapsed. In this embodiment, the DSP 85 is instructed to stop the DC voltage generation of the second and third power supply circuits PC2 and PC3. In response to this, the DSP 85 stops the voltage generation control of the second and third power supply circuits PC2 and PC3.
[0064]
That is, the copying machine of this embodiment has a “pause mode” that is a power saving mode. In this mode, when the copying machine is not used for a long time, only the 5V voltage of the first power supply circuit PC1 that generates 5V is left, and the output of other DC voltages is turned off to realize a low power consumption state. The “pause mode” is automatically shifted when the operation of the copying machine is not performed for a preset time. Alternatively, when the power subkey on the operation unit 20 is pressed for a few seconds, the process proceeds. To cancel the power saving mode, press the power subkey for a few seconds.
[0065]
FIG. 7B shows the power supply mode switching control by the CPU of the printer controller 60. From the end of the homing operation described above, the CPU of the printer controller 60 checks whether the power saving function is set. If it is set, whether the condition for shifting to the power saving “pause mode” is satisfied. If it is established (11, 12), if it is established, the DSP 85 is configured to stop the second power supply circuit PC2 that generates 24V and the third power supply circuit PC3 that supplies power to the fixing heater, and to turn off the power relay RA2. (13, 14). In response to this, the DSP 85 stops the voltage generation control of the circuits PC2 and PC3. This opens the PWM pulse output ports to these power supply circuits PC2 and PC3 to the off instruction level for FETs and transistors, and stops the PWM pulse outputs PWM2 and PWM3 to them (set the duty to 0). And by turning off the control relay RA3. Thereby, the power consumption inside the generation units PC2 and PC3 is substantially eliminated.
[0066]
For example, when the set time elapses without using the copying machine or when there is an instruction to shift to the “pause mode” by the power subkey, the CPU of the printer controller 60 sets the “pause mode” and generates 5 V in the DSP 85. Commands to stop DC voltage generation (PC2, PC3) other than the part PC1. In response to this, the DSP 85 stops the output of the second and third PWM pulses PWM2 and PWM3 to the second and third power supply circuits PC2 and PC3 and turns off the power relay RA2.
[0067]
While the “pause mode” is set, if the power sub key is pressed for a few seconds, or if there is an operator's operation on the copying machine or a print command from the host (personal computer), the CPU of the printer controller 60 Is released and the DSP 85 is instructed to return to the power source, that is, to set the “operation mode” (11, 20, 21, 22). In response to this, the DSP 85 starts to turn on the power relay RA2 and output the PWM pulse PWM3 to the third power supply circuit PC3, and refers to the detected temperature of the thermistor TH, which is less than the reload temperature 170 ° C. If there is, the temperature rises, and if the temperature of the fixing heater 123C is equal to or higher than the reload temperature 170 ° C. or becomes 170 ° C. or higher, the DSP 85 starts outputting the PWM pulse PWM2 to the second power supply circuit PC2. When the output voltage of the second power supply circuit PC2 exceeds a predetermined value, the DSP 85 notifies the CPU of the controller 60 of the power supply ready by UART communication.
[0068]
Even when the “operation mode” is set, for example, when the set number of sheets printing process is completed, the output of the PWM pulse PWM3 to the third power supply circuit PC3 is stopped (16, 17). On the contrary, when the output of PWM3 is stopped, if a printing process is required, output of PWM pulse PWM3 to the third power supply circuit PC3 is started (15, 18, 19).
[0069]
FIG. 8 shows an outline of power output control of the CPU 85a of the DSP 85. When the voltage of the battery 84 is applied to the DSP 85 by closing the relay contact RA1, an operating voltage is applied to the CPU 85a (61). This activates the CPU 85a, initializes its input / output ports, internal timers and registers, sets them to the assigned state during standby, and sets other elements of the DSP 85 to the initial state (62).
[0070]
Next, the CPU 85a starts a timer of Ts time limit for determining the reading cycle (sampling cycle) Ts of the AC instantaneous voltage V0 using the A / D converter 85i (63), and executes it in response to the time over. The timer interrupt to be performed is permitted (64). In this embodiment, Ts is 50 μsec. Therefore, when the frequency of the input AC voltage is 50 Hz (half cycle is 1000 × 1000/100 = 10000 μsec.), 200 timer interruptions are performed during the half-wave period of the input AC voltage. Processing (FIG. 9) is executed.
[0071]
When the timer interrupt is permitted, the CPU 85a starts oscillation of the PWM pulse PWM1 with the reference value duty assigned to the PWM1, and outputs it to the FET driver DRIV1 of the first power supply circuit PC1 (65). Then, the communication interruption in response to the transmission from the printer controller 60 is permitted (66a).
[0072]
The above is the initial operation of the DSP 85 corresponding to the start-up operations 1 to 4 of the DC power supply device 80 shown in FIG. 7A, whereby the first power supply circuit PC1 generates a voltage, The CPU or MPU of the control board 50 and the printer controller 60 is activated ((a) in FIG. 7). As a result, the CPU of the printer controller 60 gives a command to the CPU 85a of the DSP 85 by communication, and activates steps 6 to 9 in FIG. The task of the CPU 85a of the DSP 85 corresponding to this is shown as “activation” (66b) in FIG.
[0073]
When “start-up” (66b) starts, the CPU 85a of the DSP 85 controls the 5V and 24V output voltage control of the first and second power supply circuits, the output abnormality, and the third power supply circuit PC3 in steps 67 to 82 of FIG. Execute output error control. This control is collectively referred to as “overall control”. Even during this “overall control”, when the timer Ts expires, a timer Ts interrupt (TSI in FIG. 9) is executed. In “overall control” (steps 67 to 82 in FIG. 8), the data of the register CAR which is cleared to 0 in the last step 48 of the timer Ts interrupt (TSI in FIG. 9) is referred to (67). If it is “0” (the “total control” has not been completed since the timer Ts interrupt was completed), the “total control” execution count CNR is incremented by 1 (68), and the count value CNR is 6 Is initialized to 0 (69, 70), and "5V voltage control" (72) is executed when CNR = 0, corresponding to the count value CNR. When CNR = 1, 2, 3, 4 or 5, “5V current abnormality control” (74), “24V voltage control” (76), “24V current abnormality control” (78), “100V voltage abnormality control”, respectively. (80) or “100V current abnormality control” (82). However, the control other than the 5V system is a case where the output of PWM2 and PWM3 is instructed to the DSP 85 as a result of the switching control of the power supply mode shown in FIG. When the output stop is instructed, the corresponding control is bypassed. That is, it is not executed (75-73, 77-73, 79-73, 81-73). In any case, when “overall control” is passed once, 1 is written in the register CAR (after completion of “overall control”, the timer Ts interrupt is not executed).
[0074]
Since the data of the register CAR is manipulated as 0 and 1 as described above and it is determined in step 67 whether or not to proceed to “overall control”, when the timer Ts interrupt is completed, the above “ It is necessary to start one of the six types of control in “Overall Control”, complete it, and then complete a single timer Ts interrupt. It does not initiate another control. Accordingly, each of the six types of control in the “overall control” described above is repeatedly executed at a cycle of 6 Ts or more. As a result, Ts is set to a short time for sampling the instantaneous value of the AC input voltage and current, but the timer Ts interrupt process (TSI) is correctly repeated at the cycle Ts. The contents of the timer Ts interrupt process (TSI) will be described later with reference to FIG.
[0075]
When proceeding to “5V voltage control” (72) in FIG. 8, the CPU 85a determines the channel number of the A / D converter 85i. 0, the output voltage V1 of the first power supply circuit PC1 is A / D converted and read, and whether it is equal to or higher than the set value Rf5VU (abnormal overvoltage) or lower than the set value Rf5VL (abnormal undervoltage) To check. If it is less than the set value Rf5VU and exceeds Rf5VL, that is, within the appropriate range, the error amount for 5V of the output voltage data read this time is calculated, and the error amount is converted into a PWM pulse duty. The prescribed PWM1 data is calculated, updated and written in the PWM1 register set in the CPU 85a or RAM 85c, and the data in the PWM1 register is written in the PWM1 pulse generation control register of the pulse generator 85e. As a result, the PWM pulse output from the pulse generator 85e to the pulse output port PWM1 changes to a duty for reducing the error amount of the output voltage to zero. This is feedback control of the output voltage of the first power supply circuit PC1.
[0076]
When the output voltage of the first power supply circuit PC1 is the set value Rf5VU or more or Rf5VL or less, that is, when the voltage is abnormal, the CPU 85a writes the data of the PWM duty 0% to the PWM1 register, the PWM2 register, and the PWM3 register. As a result, all the pulse outputs (PWM1 to PWM3) of the pulse generator 85e are stopped, and the FET1, the FET2 of the second power supply circuit PC2, and the switching transistor Q of the third power supply circuit PC3 are all turned off. Next, the CPU 85a prohibits all interrupts permitted to itself. As a result, the DSP 85 stops operating until the AC voltage (switch SWap) is turned off once and turned on again, and the first power circuit PC1, the second power circuit PC2, and the third power circuit PC3 are stopped. However, there is no output.
[0077]
When proceeding to “5V current abnormality control” (74) in FIG. 8, the CPU 85a determines the channel No. of the A / D converter 85i. The output current I1 of one first power supply circuit PC1 is read, and it is checked whether it is equal to or higher than a set value Rf5ViU (overcurrent abnormality) or Rf5ViL (low current abnormality). If so, then the CPU 85a writes the data of the PWM duty 0% into the PWM1 register, the PWM2 register and the PWM3 register. As a result, all the pulse outputs (PWM 1 to 3) of the pulse generator 85e are stopped, and the FET 1 of the first power circuit PC1, the FET 2 of the second power circuit PC2, and the switching transistor Q of the third power circuit PC3 are turned off. Next, the CPU 85a prohibits all interrupts permitted to itself.
[0078]
The content of “24V voltage control” (76) in FIG. 8 is the same as that of the “5V voltage control” (72) described above, and the CPU 85a determines the channel number of the A / D converter 85i. The output voltage V2 of the second second power supply circuit PC2 is read, and the duty of the PWM2 pulse applied to the driver FET2 of the second power supply circuit PC2 is similarly feedback-controlled so that it is set to the set value 24V. If the output voltage V2 of the second power supply circuit PC2 is an overvoltage abnormality (output voltage is Rf24VU or more) or a low voltage abnormality (Rf24VL or less), the CPU 85 of the DSP 85 sets the PWM2 data to 0 (energization duty 0: energization stop). The driving of the second power supply circuit PC2 is stopped.
[0079]
The contents of “24V current abnormality control” (78) in FIG. 8 are substantially the same as the above-mentioned “5V current abnormality control” (74). In the “24V current abnormality control” (78), the CPU 85a sets the channel number of the A / D converter 85i. When the output current I2 of the second power supply circuit PC2 of No. 3 is read and it is an overcurrent abnormality (output current is Rf24iU or more) or a low current abnormality (Rf24iL or less), the PWM2 data is set to zero. That is, the driving of the second power supply circuit PC2 is stopped.
[0080]
In “100V voltage abnormality control” (80) in FIG. 8, the CPU 85a sets the channel number of the A / D converter 85i. The output voltage V3 of the third power supply circuit PC3 is read, and if it is an overvoltage abnormality (output voltage is Rf100VU or more) or a low voltage abnormality (Rf100VL or less), the PWM3 data is set to zero. That is, the driving of the third power supply circuit PC3 is stopped.
[0081]
In “100V current abnormality control” (82) in FIG. 8, the CPU 85a determines the channel number of the A / D converter 85i. The output current I3 of the third power supply circuit PC3 is read, and if it is an overcurrent abnormality (output current is Rf100iU or more) or a low current abnormality (Rf100iL or less), the PWM3 data is set to zero. That is, the driving of the third power supply circuit PC3 is stopped.
[0082]
Please refer to FIG. In response to the timer Ts time-over, the CPU 85a of the DSP 85 proceeds to the “timer interrupt” (TSI) shown in FIG. 9, and first restarts the timer Ts to determine the time until the next timer Ts interrupt ( 30). Next, the CPU 85a sends an input channel No. to the A / D converter 85i. 7 is input, the digital data converted by the A / D converter 85i, and the instantaneous voltage value data V0 of the AC input voltage at this time are read and saved in the register RV0 (31). The register refers to one area of the internal memory of the CPU 85a.
[0083]
Next, the CPU 85a checks whether the output of PWM3 is instructed to the DSP 85 (PWM3 output required) as a result of the switching control of the power supply mode shown in FIG. If so, “constant current control” (33) is executed. The content of “constant current control” (33) is shown in FIG. 10 and will be described later.
[0084]
If the output of PWM3 is unnecessary, or if "constant current control" (33) is executed, the CPU 85a next processes the instantaneous voltage value data V0 read this time in the previous process (here, TSI before 50 μsec.). Compared with the instantaneous voltage value data PV0 detected in step S34 and stored in the register RPV0 (34), if it is larger than the previous value PV0, the current value V0 is stored in the register RPeV0 as the peak voltage PeV0 (35). Next, in order to determine whether the peak voltage value PeV0 is a true peak voltage, the cumulative AiV0 of the increment V0-PV0 from the previous value PV0 is calculated to update the cumulative AiV0 (36). Next, the current value V0 is stored in the register RPV0 as the previous value PV0 (37), the register CAR is cleared (48), and the current interrupt process is terminated.
[0085]
On the other hand, if the current value V0 is smaller than the previous value PV0, the cumulative ArV0 of the decrease PV0-V0 which is the difference is calculated and the cumulative ArV0 is updated (38). Next, the current value V0 is stored in the register RPV0 as the previous value PV0 (39). Thereafter, in order to determine whether the data PeV0 stored as the detected value of the peak voltage is a true peak, it is determined whether the input voltage is detected within a period in which the input voltage is decreased by 100 V or more and increased by 50 V or more. (40, 41) If it does not conform to this, it is determined that the data PeV0 is not a true peak voltage, the register CAR is cleared (48), and the current interrupt process is terminated.
[0086]
However, if it matches, the data PeV0 is determined as the true peak voltage, and the peak value Vp of the register RVp, which is the peak voltage detected in the previous half cycle, is moved to the register RPVp as the previous peak value PVp (42), The peak value PeV0 detected this time is stored in the register RVp as the peak value Vp of the current half cycle (43). Next, an average value Vp of positive and negative peak voltages PVp (data of the register RPVp) and Vp (data of the register RPe), which is one cycle of the AC power supply, is calculated (44). Next, a ratio of a reference peak voltage value Vps (this is a value at the rated voltage of the AC power supply, and here, it is 100 Vrms, 141 V = 100 Vrms × √2) to the average value Vp, Kv = Vps / Vp is calculated (45). This ratio Kv is used to generate a target instantaneous value of the current corresponding to the input voltage instantaneous value V0 in “constant current control” (33) described later. Next, the CPU 85a resets the cumulative AiV0 for the increase and the cumulative ArV0 for the decrease (46, 46), clears the register CAR (48), and ends the current interrupt process.
[0087]
Next, the contents of “constant current control” (33) will be described with reference to FIG. Here, the CPU 85a first inputs an input channel No. to the A / D converter 85i. 8 is input, digital data converted by the A / D converter 85i, and fixing temperature data THM representing the temperature detected by the fixing temperature sensor TH at this time are read and saved in the register RTH (51 ). Next, the CPU 85a checks whether or not the fixing temperature THM is equal to or lower than a predetermined value (here, 180 ° C.) (52), and if it exceeds, the duty of the PWM pulse PWM3 is designated as 0% (53), and the PWM pulse The output of PWM3 from the generator 85e is stopped. As a result, the switching transistor Q of the third power supply circuit PC3 is kept off, and the energization to the fixing heater 123C is stopped.
[0088]
When the fixing temperature THM is equal to or lower than a predetermined value (here, 180 ° C.), the fixing heater 123C is energized so that the AC input current of the DC power supply device 80 becomes the AC rated current (effective value 15A) of the device 80. Therefore, the detected instantaneous voltage value V0 is calibrated to the rated instantaneous voltage value Vs equivalent value AV0 = Kv × V0 in the same phase (54), and the rated instantaneous current value Is equivalent value TI0 = AV0 × of the input current at that voltage. Ki is calculated and used as an instantaneous current target value (55).
[0089]
In this embodiment, since the rated voltage of the AC input of the DC power supply 80 is 100 V (effective value) and the rated current is 15 A, the load resistance (Vs / Is) at that time is 100 / 15≈6.7Ω, and its reciprocal number. Ki = Is / Vs = 15/100 = 0.15.
[0090]
Next, the CPU 85a determines the channel number of the A / D converter 85i. 6, the detection signal of the current detection circuit ISEN0 representing the instantaneous value I0 of the AC input current is A / D converted and read and stored in the register RI0 (56). Then, a deviation TI0-I0 of the detected value I0 with respect to the instantaneous current target value TI0 is calculated, and a duty correction amount G · (TI0-I0) of the PWM pulse PWM3 for setting this to 0 is calculated. The correction is added to the currently set duty,
Duty after correction = duty of current PWM3 + G · (TI0-I0)
Is designated as the duty of PWM3 (58). As a result, the PWM3 output from the PWM pulse generator 85e to the switching transistor Q of the third power supply circuit PC3 is the rated instantaneous current value Is at the rated instantaneous voltage value Vs corresponding to the instantaneous voltage value V0 (ie AV0 = Kv × V0). (Ie, TI0 = AV0 × Ki = Ki × Kv × V0) is a PWM duty that matches the input AC current instantaneous value I0, and I0 = Ki · V0. That is, the input alternating current (I0) has a rated current value (15A) similar to the waveform of the input alternating voltage (V0).
[0091]
As described above, the CPU 85a of the DSP 85 controls the load current supplied to the fixing heater 123C in order to keep the fixing temperature at a predetermined value of 180 ° C. This control includes controlling the load current (here, the fixing heater) so that the input current from the AC power source to the DC power source device 80 is within the allowable rated current (here, effective value 15 A). It is out.
[0092]
In this embodiment, in order to mainly improve the temperature responsiveness of the fixing heater 123C, the maximum load current is supplied in the range of the input current allowed to the DC power supply device 80. Since this load current fluctuates depending on the energization state of the load other than the fixing heater 123C (for example, during printing or during printing standby), the input current I0 is detected and the load current is controlled within the range. Yes. The AC power supply is generally a sine wave, but the instantaneous value V0 of the power supply voltage is detected so that the input current I0 is similar to the waveform of the power supply voltage, and a constant current is set so as to obtain a current value corresponding to the voltage. Control is performed. Further, the power supply voltage V0 of the AC power supply also varies depending on the presence or absence of other devices connected to the AC power supply, so that the rated current is set regardless of this variation.
[0093]
FIG. 11 shows a control sequence by the CPU 85a of the DSP 85 drawn in correspondence with the waveform of the AC power supply. The power supply voltage shown in FIG. 11 is an input voltage waveform from the AC power supply to the DC power supply device 80, and the voltage is 100 V (effective value). The detection voltage is a waveform of a voltage appearing at the voltage dividing resistor R2 of the third power supply circuit PC3. When power relay RA2 is turned on, a detection voltage is generated. When the CPU 85a of the DSP 85 is instructed to output PWM3 from the printer controller 60, the CPU 85a enters the aforementioned "constant current control" (33), and only when the fixing temperature THM is equal to or lower than a predetermined value (180 ° C). Load current value control in which the AC input current I0 is the rated current value Is, that is, energization of the fixing heater 123C is performed.
[0094]
The detection of the peak voltage Pe is detected in order to allow the rated current to flow despite the deviation of the detection voltage V0 from the rated voltage Vs, that is, the fluctuation of the input AC voltage, and when the peak voltage Pe (input AC voltage) is low, Accordingly, the detection voltage V0 is corrected to be higher (AV0 = Kv · V0). Therefore, in the timer Ts interrupt (TSI), first, the positive / negative of the AC voltage within one cycle (here, phase 0 to 360 degrees) from the detection voltage V0 that is full-wave rectified at the peak voltage detection: n. Polarity peak voltages Vp: 1p and Vp: 1m are detected, respectively, and the average value is determined as the peak voltage of the cycle. Based on this, the constant current control: n is executed in the next half cycle (here, the phase is 360 degrees to 540 degrees), and one constant current control is completed.
[0095]
Next, the remaining half period (here, phase 540 degrees to 720 degrees) is the peak voltage Vp detected in parallel with the data Vp: 1 m after the previously detected peak voltage and constant current control: n. : The average value of 2P is determined as the peak voltage of the previous cycle (phase 180 to 540 degrees), and constant current control: n + 1 is executed. Thereafter, the peak voltage Pe is determined by repeating this process.
[0096]
FIG. 12 schematically shows the sampling timing of the constant current control within the half cycle described in FIG. The target input current represents the rated current as an absolute value. The frequency of the AC power supply is 50 Hz. The constant current control is repeatedly executed at a cycle of Ts = 50 μS (20 KHz). In this process, a target value (instantaneous current target value TI0) of the input current corresponding to the input voltage (AC instantaneous voltage V0) at that time is calculated, and the input instantaneous current value I0 becomes the target value. The load current supplied to the fixing heater 123C is controlled by PWM control (pulse width modulation control) of the switching transistor Q.
[0097]
The target value TI0 is calculated based on the input instantaneous voltage V0. However, since the input instantaneous voltage V0 may fluctuate, the ratio of the peak voltage Vps of the rated voltage to the peak voltage Vp detected in the previous one cycle. Correction (normalization of input voltage) is performed using Kv.
[0098]
FIG. 13 shows the sampling timing of FIG. 12 with the time axis further enlarged. In the PWM control, the cycle is fixed to Ts and the transistor on-time is controlled, and the duty (energization duty) that is the ratio of the on-time to the PWM cycle Ts is varied from 0 to 100%. That is, the pulse duty [high-level H interval width / pulse period Ts] × 100% of the PWM3 signal shown in FIG. 13 is varied from 0 to 100%. The PWM3 signal is generated by the PWM pulse generator 85e and is supplied to the drive circuit DRIV3 of the third power supply circuit PC3. The drive circuit DRIV3 turns on the switching transistor Q in the high level H section of the PWM3 signal, and the low level L Turn off at intervals. Therefore, a pulse current flows through the fixing heater 123C, and the time series average value is proportional to the duty.
[0099]
【Effect of the invention】
If the AC instantaneous voltage V0 indicates a change in sine wave, the AC instantaneous current I0 indicates a change in sine wave, and the waveform distortion of the AC input current is reduced. When the power supply environment for one load (123C) is favorable, such as when the voltage of the AC power supply (Vp) is high or the number of simultaneous power supply loads is small, the power supply current value for the load (123C) automatically increases. For example, when the load is a fixing heater (123C), the temperature rises quickly, and the delay time until image formation is possible when returning from the sleep mode for energy saving to the operation mode for image formation or preparation is short. In addition, during the constant temperature control, the temperature rise during energization is fast, so that the stability of the fixing temperature is increased.
[Brief description of the drawings]
FIG. 1 is a front view showing an external appearance of a multifunction copying machine including a printer 100 equipped with a power supply device 80 according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an outline of an image forming mechanism of the printer 100 shown in FIG.
3 is a block diagram showing a system configuration of an electric system of the copying machine shown in FIG.
4 is a block diagram showing an outline of a power supply circuit on the DC power supply device 80 shown in FIG. 3. FIG.
FIG. 5 is an electric circuit diagram showing a partial circuit configuration of first to third power supply circuits PC1 to PC3 shown in FIG. 4;
6 is a block diagram showing an electrical system of the DSP 85 shown in FIG.
7A is a flowchart showing an outline of processing for starting the copier immediately after the main power switch SWap of the DC power supply device 80 and the printer controller 60 shown in FIG. 4 is turned on; FIG. ) Is a flowchart showing on / off control of the power output of the printer controller 60 after the start-up is completed.
8 is a flowchart showing the contents of power supply circuit control of the CPU 85a of the DSP 85 shown in FIG.
9 is a flowchart showing the contents of an interrupt process in response to the time-out of the Ts time timer of the CPU 85a of the DSP 85 shown in FIG.
FIG. 10 is a flowchart showing the contents of “constant current control” (33) shown in FIG. 9;
11 is a time chart showing the AC voltage supplied to DC power supply device 80 shown in FIG. 4, the voltage detected without device 80, and the timing of peak voltage detection and constant current control by CPU 85a. FIG.
12 is a time chart showing AC voltage and target current supplied to DC power supply device 80 shown in FIG. 4, and sampling timing of voltage and current. FIG.
13 is a pulse signal PWM3 given to the third power supply circuit PC3 by the DSP 85 shown in FIG. 6, and the heater current output from the third power supply circuit PC3 in response to this, and the AC input current due to the outflow of the heater current. It is a time chart which shows a change.
[Explanation of symbols]
101: Photoconductor belt 102, 103: Rotating roller
104: Charging charger 105: Laser exposure apparatus
106: Color developing device 107: Cleaning blade
109: Intermediate transfer belt 110-112: Rotating roller
113: Bias roller 114: Transfer roller
115: Cleaning device 116: Paper feed stand
117: Paper feed roller 118a, 118b: Pair of transport rollers
119a, 119b: registration roller pair
120: fixing device 121a, 121b: pair of paper discharge rollers
122: Paper discharge stack

Claims (6)

In a method of receiving AC power and supplying adjusted power to a load,
Detects the instantaneous voltage value , instantaneous current value and peak voltage value of AC input,
With respect to the peak voltage value, the ratio of the peak voltage reference value is the peak voltage value when the AC input voltage rating and current rating, and the instantaneous obtained by multiplying the ratio of the rated current for the rated voltage, to the instantaneous voltage value Generate current target value,
A power feeding method characterized by controlling power feeding to a load so that an instantaneous current value of an AC input matches the instantaneous current target value. That issues detects the peak voltage value step by time-series change in the instantaneous voltage value of the AC input, power supply method according to claim 1. In a power supply device that receives AC power and supplies power adjusted to a load,
Means for detecting the instantaneous voltage value of the AC input;
Means for detecting an instantaneous current value of the AC input;
Means for detecting a peak voltage value of the AC input voltage;
With respect to the peak voltage value, the ratio of the peak voltage reference value is the peak voltage value when the AC input voltage rating and current rating, and the instantaneous obtained by multiplying the ratio of the rated current for the rated voltage, to the instantaneous voltage value Means for generating a current target value; and
Power supply control means for controlling the power supplied to the load so that the instantaneous current value of the AC input matches the instantaneous current target value;
A power supply apparatus comprising: 4. The power supply device according to claim 3, wherein the means for detecting the peak voltage value of the AC input voltage detects the positive and negative peak voltages during one cycle of the AC input, and uses the average value as the peak voltage value. A visible image forming apparatus having a means for inputting an operator instruction and a control means, and forming a visible image corresponding to an image signal on a sheet; an energization adjustment for adjusting power supplied to an electrical load of the visible image forming apparatus; Means; and a power supply device according to claim 3,
The power supply control means of the power supply device changes the power supply control signal supplied to the power supply adjusting means so that the instantaneous current value of the AC input matches the instantaneous current target value;
Image forming apparatus. The power supply control signal is a PWM pulse, and the energization adjusting means to which it is applied is a switching means for energizing the fixing heater;
The power supply control means changes the power supply control signal to a value that reduces the deviation corresponding to the deviation of the instantaneous current value with respect to the instantaneous current target value, and the temperature sensor of the visible image forming apparatus When the detected fixing temperature is equal to or lower than the set value, the duty of the PWM pulse is changed to one that reduces the deviation, and when the fixing temperature exceeds the set value, the energizing current value of the fixing heater is set to a low value including zero. Restrict;
The image forming apparatus according to claim 5.

Images