JP2013244699A - Multifunctional printer apparatus and method for controlling power supply thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunctional printer apparatus equipped with a switching power supply circuit which switches a control mode of a switching power supply between an operation mode and a standby mode in particular and thus further improves power saving at the time of the standby mode, regarding power saving of the apparatus.SOLUTION: A control signal is supplied to a switching power supply circuit, according to a state of an operation mode making one of a printer function, a scanner function and a copy function of a multifunctional printer apparatus operate or a standby mode wherein these functions do not operate. Next, in some states of the operation mode and the standby mode, the operation of the switching power supply circuit is switched over to a feedback control of an electric current mode by the control signal to make a control to supply power to the power of each part of the apparatus. In some state of the standby mode, in another way, the operation of the switching power supply circuit is switched over to an open loop control or a feedback control of a voltage mode by the control signal to make a control to stop part of power supply to a display unit.

Description

  The present invention relates to a multifunction printer apparatus and a voltage generation method thereof, and more particularly to a multifunction printer apparatus that records an image on a recording medium using, for example, an inkjet recording head, and a power supply control method thereof.

  In recent years, inkjet printers, which are computer peripherals, have evolved into multifunction printers that include scanner functions, copy functions, and even facsimile functions. Due to their high cost-performance ratio, their penetration into the market has been increasing year by year. It is deepening.

  On the other hand, global environmental conservation activities in recent years, the US Energy Star Program, the EU Ecolabel, the German Blue Angel, and various energy conservation regulations represented by the Energy Conservation Law in Japan are spreading. For this reason, energy saving standards for electronic devices are becoming stricter year by year regardless of whether they are office equipment or home appliances.

  In general, switching power supplies are used as power supplies for inkjet printers, and dropper power supplies that operate at conventional commercial frequencies (50/60 Hz) are inferior in terms of weight, power conversion efficiency, heat generation, etc. Is decreasing.

  Switching power supplies are classified into several types based on the switching method, but the flyback method is most frequently used from the viewpoint of the simplicity and cost of its circuit configuration. Recently, many dedicated control ICs for such a flyback system have been provided by manufacturers, and it has become possible to design a circuit having high reliability relatively easily.

  FIG. 15 is a circuit diagram showing an example of a conventional switching power supply using a flyback method. In this example, IC1 is a commercially available PWM control IC and realizes feedback control in the current mode. The outline of the operation of the circuit shown in FIG. 15 will be described below.

  An input voltage having a commercial frequency of 50 Hz or 60 Hz is rectified by the bridge diode BD1, and then smoothed by the electrolytic capacitor C1 to generate a DC voltage Vin (DC). This DC voltage Vin (DC) is about 140V in Japan and about 320V in 230V regions such as Europe. This DC voltage Vin (DC) is supplied to the transformer T1 and is subjected to switching control by the transistor Q1, and as a result, the energy stored in the primary winding 11 of the transformer T1 is transmitted to the secondary winding 12, A DC output voltage Vo is generated.

  More specifically, in the flyback method, energy is stored in the primary winding 11 of the transformer during the turn-on period of the transistor Q1 in FIG. 15, and the stored energy is stored in the secondary winding during the OFF period of the transistor Q1. 12 is transmitted. The energy transmitted to the secondary winding 12 in this way is rectified and smoothed by the diode D2 and the electrolytic capacitor C4, and a DC output voltage Vo is generated. The output voltage Vo is divided by resistors R6 and R7, and the divided voltage is input to a reference terminal Vref1 of a constant voltage regulator, so-called shunt regulator IC3. The shunt regulator IC3 is a kind of so-called inverting error amplifier. In this example, the output voltage Vk is controlled so that the reference voltage Vref1 of the reference terminal of the IC3 is always DC2.5V, and feedback control is achieved.

  For example, when the output voltage Vo increases and as a result the input voltage Vref1 of the shunt regulator IC3 increases, the output Vk of the shunt regulator IC3 decreases conversely. As a result, the current flowing through the resistor R9 and the LED 15 of the optical coupling element (photocoupler) IC2 increases. Then, the collector current flowing through the phototransistor 16 of the photocoupler IC2 increases, and the potential of the feedback terminal FB of the control IC1 decreases. Then, the pulse width of the PWM signal that is finally output from the DRV terminal of IC1, in other words, the on-duty is reduced, and as a result, the turn-on time of the transistor Q1 is shortened (conversely, the turn-off time is increased). As a result, the energy stored in the primary side winding 11 of the transformer is reduced, whereby the energy transmitted to the secondary side winding 12 is also reduced, and the output voltage Vo is finally lowered.

  In this way, when the output voltage Vo rises, feedback control acts so as to cancel it. On the other hand, when the output voltage Vo decreases, the feedback control acts so as to increase it, so that a stable DC output voltage Vo can be obtained. More specifically, the circuit surrounded by the broken line 14 in FIG. 15 is responsible for gain adjustment and phase adjustment for such feedback control, and plays the role of stably operating the entire system. Specifically, the resistor R8 and the capacitor C5 within the broken line 14 correspond to such gain / phase adjustment parameters.

  Continuing with reference to FIG. 15, the transformer T1 is provided with an auxiliary winding 13, which is used to generate a power supply voltage Vcc for the control IC1. More specifically, the voltage generated by the auxiliary winding 13 is rectified and smoothed by the diode D1 and the electrolytic capacitor C3, and further stepped down by the transistor Q2 and the Zener diode ZD1 to generate the power supply voltage Vcc of the control IC1. . In the example of FIG. 15, Vcc = 15V, and therefore the Zener diode ZD1 also has the 15V specification.

  Next, details of the operation of the switching power supply circuit shown in FIG. 15 will be described with reference to waveforms of respective parts.

  FIG. 16 shows the drain-source voltage Vds of the transistor Q1, the drain current Id, the current flowing through the transformer secondary winding 12, the current Is flowing through the rectifier diode D2, and the output current Io in the switching power supply. It is a signal waveform diagram.

  FIG. 16 shows a waveform of the current discontinuous mode as a representative example even in the flyback method. As will be apparent to those skilled in the art, when the load power is increased and the PWM on-duty is 50% or more, the current discontinuous mode transitions to the current continuous mode, which is directly related to the gist of the present invention. Since it is not a thing, the description is omitted.

In FIG. 16, the basic period T of the switching operation is, for example, 16.7 μsec when the operating frequency is 60 KHz. During this time, there is a period Ton in which the transistor Q1 is turned on and a turn-off period Toff. Furthermore, in the Toff period, energy is released from the secondary winding 12 of the transformer 12 through the diode D2 and the electrolytic capacitor C4, and a waiting period Toff2 until the emission is completed and the transistor Q1 is turned on again after the emission is completed. And are included. During the period Toff2, it can be seen that the drain-source voltage of the transistor Q1 resonates as shown. This is generally a phenomenon caused by a resonance system formed by the inductance value L ₁ and leakage inductance value Lleak of the primary winding 11 of the transformer and the total capacitance value Clump between the drain and source of the transistor Q1. However, since this phenomenon is not directly related to the gist of the present invention, detailed description is omitted here.

In FIG. 16, in the current discontinuous mode as illustrated, the energy given by the equation (1) is accumulated in the primary winding 11 of the transformer during the Ton period. That is,
P ₁ = 1/2 * L ₁ * Ip ² (1)
It is. Here, L ₁ is the inductance value of the primary winding 11, and Ip is the peak value of the current flowing in the primary winding 11 during the Ton period, as shown in FIG.

Next, the energy generated by the transformer per unit time is expressed by Equation (2). That is,
P ₂ = 1/2 * L ₁ * Ip ² * f * η (2)
It is. Here, f indicates the switching frequency, η indicates the energy conversion efficiency of the transformer, and a value obtained by multiplying the energy amount P ₁ generated on the primary side of the transformer by the efficiency η is actually transmitted to the secondary side of the transformer. Energy amount. For example, f is 60 KHz or 100 KHz, and η is 0.95.

  That is, about 95% of the energy generated on the primary side of the transformer is transmitted to the secondary side, and the remaining about 5% is lost as heat by the core and windings of the transformer. As a reference, the overall efficiency of a flyback switching power supply with an output of several tens of watts is approximately 85%. In addition to the above-described loss of the transformer alone, the loss due to the EMI filter circuit (not shown) of the input section, the loss due to the switching element Q1, the loss due to the rectifying element D2 in the secondary side circuit, and the like, in the circuit of FIG. Loss due to the resistance element.

Referring to FIG. 16 again, in equation (1), energy P ₁ accumulated in the Ton period is transmitted to the secondary winding 12 of the transformer in the Toff1 period. This switching control method is called a flyback method. On the other hand, there is a system in which energy is transmitted from the primary side to the secondary side of the transformer in both the Ton period and the Toff period of the transistor Q1, and this is referred to as a forward system. For details, refer to technical books.

  Now, there are current mode control and voltage mode control in the flyback system. Here, referring to FIG. 17, the reason why the circuit of FIG. 15 is called the current mode control system will be briefly described. .

  FIG. 17 is a diagram showing in detail the main part of the control IC 1 of FIG. In FIG. 17, the same elements as those in FIG. 15 are denoted by the same reference numerals.

  In FIG. 17, a detected value 24 obtained by detecting the drain current Id flowing through the transistor Q1 by the resistor R3 is input to one input terminal of the comparator 27 (shown as 24A), and the reference voltage 23 input to the other input terminal. As a result, the PWM signal 28 is generated. Here, the reference voltage 23 is a value Vfb ′ obtained by dividing the FB signal, which is the output of the photocoupler IC2, into one third inside the control IC1.

  In this way, the reference voltage 23 and the current component 24A of the switching operation are compared to achieve feedback control, which is referred to as current mode control.

  On the other hand, when the object to be compared with the reference voltage is, for example, a voltage component such as an output voltage, it is called voltage control. As a feature of the present invention, in the standby mode, the feedback control is switched from the current mode to the voltage mode, which will be described later together with an embodiment.

  Referring to FIG. 17 in further detail, the collector of the phototransistor 16 of the photocoupler IC2 is connected to the FB terminal 35 of the control IC1. The FB terminal 35 is pulled up by the resistor 21 inside the IC 1, and as a result, the collector current of the phototransistor 16 is controlled according to the increase / decrease of the current flowing through the LED 15 of the photocoupler IC 2.

  Specifically, as the current flowing through the LED 15 increases, the current flowing through the phototransistor 16 also increases, thereby increasing the voltage drop across the resistor 21 and lowering the voltage at the FB terminal 35. The FB voltage is then reduced to a third value by the voltage divider circuit. Then, the divided voltage value Vfb′23 is input to one input terminal (−input) of the comparator 27. On the other hand, the detected value 24 of the drain current Id of the transistor Q1, that is, the value Vcs obtained by detecting the drain current Id with the resistor R3 is input to the other input terminal (+ input) of the comparator 27 via the LEB circuit 26. Is done.

  LEB is an abbreviation for Leading Edge Blanking circuit, and is provided for the purpose of ignoring the noise component immediately after the transistor Q1 is turned on and avoiding false detection. For example, the LEB masks the Vcs signal for 150 nsec immediately after the transistor Q1 is turned on. do. Further, a triangular wave-shaped correction current 25 synchronized with the switching period is injected into the CS pin 36, and the sense voltage Vcs is corrected through the resistor R4. The correction current 25 is injected in order to prevent abnormal oscillation called a subharmonic phenomenon in the above-described continuous current mode with a duty of 50% or more. However, the correction current 25 is not directly related to the gist of the present invention, and thus the description thereof is omitted. .

  As described above, the voltage Vfb ′ as the reference voltage 23 and the drain current Vcs (24A) of the transistor Q1 are compared by the comparator 27, and the PWM signal 28 is generated. As shown, the PWM signal 32 is generated by a flip-flop 31. Specifically, the PWM signal 32 is set by the output signal 30 (Clock) of the oscillator 29 that provides the source oscillation of the switching control and is reset by the PWM signal 28. The PWM signal thus generated is output to the output terminal (DRV) 34 through the current drive gate 33. This output signal (DRV signal) is input to the gate of the transistor Q1 (FIG. 15) via the resistor R2, and the transistor Q1 is subjected to switching control.

  FIG. 18 is a time chart of the PWM signal 32 and the output signal 30 (Clock) of the oscillator 29. In FIG. 18, a PWM signal 32 is generated by two inputs to the comparator 27, that is, a reference voltage Vfb'23, a voltage Vcs24A corresponding to the drain current of the transistor Q1, and an output signal 30 (Clock). The situation is shown. As illustrated, for example, when the reference voltage 23 (Vfb ′) gradually increases, it can be seen that the turn-on period Ton of the PWM signal gradually increases.

  The flyback method current mode control has been described above with reference to FIGS. 15 to 18. Next, conventional energy saving control in this method will be described with reference to FIG.

  FIG. 19 is a diagram illustrating a state in which the intermittent power supply operation is performed due to excessive power supply in the continuous switching operation as a result of considerably reducing the load power in the circuit of FIG.

Specifically, the FB terminal voltage V _FB of the control IC 1 in FIG. 17 is compared with the _skip threshold voltage V _skip indicated by the broken line in FIG. Only during the period when V _FB exceeds the V _skip level, the switching operation is executed at the basic switching frequency (for example, 60 KHz). As a result, the switching operation is intermittent oscillation as shown.

Here, the skip threshold voltage V _skip is determined according to the specification of the control IC1, and in one example, as shown in FIG. 20, the control mode of the control IC 1 is determined corresponding to the voltage _VFB . In the example shown in FIG. 20, the skip threshold voltage V _skip is set to 1V. Accordingly, when V _FB ≦ 1V, the skip operation in FIG. 19 is executed, while when V _FB > 3V, it is regarded as an overload state (overload), and a protective operation such as shutdown works. Therefore, a PWM operation based on the basic switching frequency is executed when 1V <V _FB ≦ 3V. For details of the above-described skip operation, see, for example, Patent Documents 1 and 2.

  On the other hand, as another energy saving technique for the switching power supply, a technique for reducing the switching frequency as the load power decreases is also known.

  FIG. 21 is a diagram showing an example of a technique for reducing the switching frequency in accordance with the reduction in load power, and this figure shows the relationship between the feedback voltage (FB) and the switching frequency (Freq) of the circuit of FIG.

  As described above, when the load power increases, the feedback voltage (FB) itself also increases. As is apparent from FIG. 21, when the feedback voltage is Vfb2 ≦ FB <Vfb3, PWM control is executed at a fundamental frequency, for example, 60 KHz. On the other hand, when Vfb1 ≦ FB <Vfb2, the switching frequency gradually changes. Such control is called PFM (pulse frequency modulation). As shown in the figure, when FB = Vfb1, the switching frequency is the lowest frequency f (min), which is preferably set to, for example, the upper limit value 15 KHz of a human audible sound range. In the region of FB ≦ Vfb, PWM control is executed at the lowest frequency.

  In this region, the skip operation described with reference to FIG. 19 is executed at the lowest frequency. For PFM control, see, for example, Patent Documents 3 to 6.

  Nowadays, inkjet printers have become popular in the market as color printers and generally form color images using recording heads that eject at least four colors of cyan, magenta, yellow, and black. To do. Further, some high-end machines, for example, perform recording by ejecting cyan and magenta dark and light inks, or perform recording using inks of special colors such as pink and orange.

  In order to form a high-quality image with such a recording head, it is necessary to control the voltage for driving the recording head with high precision. For this reason, the switching power supply is a DC voltage with high precision, for example, 1% precision. (For example, DC24V) must be output.

  In order to achieve such a high-accuracy output voltage, a normal switching power supply always detects the output voltage generated by the secondary side circuit and feeds back the result to the primary side circuit, thereby turning on / off the switching element. Duty must be controlled. Such a feedback system is generally called closed loop control.

  On the other hand, there is a control referred to as an open loop, which controls the switching element based on some algorithm or idea without detecting the output voltage generated by the secondary side circuit. These open loop features have the following advantages: That is, the circuit configuration is simpler than the closed loop (no feedback circuit is required) and the cost is low. Further, as will be described below, the standby power will be set to a very strict standard in the future (for example, 0.2 Since it can be cleared even in watts or less, it is excellent in terms of energy saving. On the other hand, since the switching element is controlled without detecting the output voltage, the output voltage accuracy is lowered.

  By the way, as described above, the ink jet printer has to control the recording head with a high precision voltage during the recording operation, while the recording head does not operate during standby, and the drive motors do not operate. Accordingly, at least a highly accurate recording head voltage is not required. In general, only control logic including a CPU, an ASIC, a memory, and the like operates during standby. These control logics require a low voltage such as, for example, DC5V, DC3.3V, or DC1.5V. For reference, for example, DC5V is used for various sensors, switches, etc., DC3.3V is used for USB interface control system, ASIC input / output unit or memory device, and DC1.5V is the core part of ASIC and CPU. Used for etc.

  Generally, these various low voltages are generated from one output of the switching power supply via a DC-DC converter, or generated in a step-down manner by a constant voltage regulator device.

  In particular, recently, the energy star program mentioned above requires PC peripheral devices such as inkjet printers to consume less than 1 watt during standby, and the standard will be strengthened to about 0.5 watts in the future. There are also predictions. However, in recent inkjet printers, as the apparatus has become multifunctional as described above, it is necessary to store given information even during standby, and for maintenance and management of the recording head, There is a need to measure the elapsed time by the CPU. In other words, even during standby, power supply for operating some memories and power supply for operating the ASIC or CPU are required.

  In order to satisfy these strong energy-saving requirements while at the same time satisfying the above-mentioned functions required during standby, in an example, at the time of standby, only the minimum necessary DC output is generated and unnecessary ones are generated. There is an example to avoid (see, for example, Patent Document 7).

  Specifically, only the DC-DC converter related to the generation of the necessary voltage is operated, and others are stopped, or the input of the constant voltage regulator corresponding to the unnecessary voltage is cut off. As a result, at the time of standby, in order to operate only the ASIC, the CPU, or a part of the memory, for example, only 1.5V DC can be generated and other outputs can be stopped. As for the operating clock of the ASIC or CPU, the clock frequency is reduced to one-several tens or hundreds of times in the standby mode as compared with the operation mode, and control for reducing power consumption is widely implemented. ing.

US Pat. No. 6,385,061 JP 2008-245419 A JP 2003-319645 A JP 2004-096982 A JP 2006-149067 A JP 2008-187813 A JP 2001-353930 A

  A switching power supply used in a conventional ink jet printer is generally a flyback method, and more specifically, a feedback method called a current mode that is excellent in transient response to a load change is adopted.

  However, since the current mode feedback method normally consumes several tens of mW of power in the feedback circuit as described above, the energy saving standard during standby is, for example, under extremely severe conditions such as 0.2 W or less. Adopting is inconvenient. In addition, under such extremely small power consumption requirements, the power conversion efficiency of the power supply itself is also small, generally about 50% at most.

  Therefore, assuming a power conversion efficiency of 50%, for example, in order to satisfy the energy saving standard of 0.2 W in the input power, the power consumption in the secondary circuit must be suppressed to about 0.1 W. As described above, in the recent trend toward higher functionality of inkjet printers, how to achieve power saving during standby has become a major issue.

  For example, in the feedback circuit surrounded by the broken line 14 in FIG. 15, the current flowing through the LED 15 of the photocoupler IC2 is large when the load is light, such as in the energy saving mode, and thereby the collector current of the phototransistor 16 is large. As a result, the feedback voltage of the control IC decreases. On the other hand, when the load is heavy, the current flowing through the LED 15 of the photocoupler IC2 decreases, the collector current of the phototransistor 16 also decreases, and the feedback voltage increases. Therefore, the power consumed by the IC 2 in the energy saving mode becomes larger than that in the steady load, which is an undesirable result.

  The present invention has been made in view of the above-described conventional example. A multi-function capable of generating a highly accurate output voltage during a recording operation while ensuring a minimum necessary operation during a standby operation and saving power. It is an object of the present invention to provide a printer apparatus and its power supply control method.

  In order to achieve the above object, the multi-function printer of the present invention has the following configuration.

  That is, a printer function that scans a recording head by a motor and conveys the recording medium to perform recording on the recording medium, a scanner function that scans a scanner and reads an image original, and a scanner that reads the image original by the scanner A multi-function printer that executes a copy function for copying the read image to the recording medium, the printer function, the scanner function, and display means for displaying an operation status related to the copy function; and A switching power supply circuit for supplying power to the motor, the recording head, the scanner, and the display means; an operation mode for operating any one of the printer function, the scanner function, and the copy function; and the printer function , The scanner function, and the standby mode in which the copy function is not operating Therefore, a control signal is supplied to the switching power supply circuit, and control means for controlling the supply of electric power supplied from the switching power supply circuit to each part of the device is provided, the switching power supply circuit according to the control signal, The operation of the switching power supply circuit is switched between open-loop control or voltage-mode feedback control and current-mode feedback control. The operation of the switching power supply circuit is switched to feedback control in the current mode by a control signal, and is controlled so as to be supplied to the power of each part of the device. In some states of the standby mode, the control signal The operation of the switching power supply circuit is controlled by the open loop control or It is switched to the feedback control of the pressure mode, and controls so as to stop the portion of the power supply to the display means.

  According to another aspect of the present invention, a printer function that scans a recording head with a motor to convey a recording medium and records on the recording medium, a scanner function that scans a scanner and reads an image original, and the image A power supply control method for a multi-function printer that performs a copy function of reading a document by the scanner and copying the image read by the recording head onto the recording medium, wherein the multi-function printer includes the printer function, The method comprising: display means for displaying an operation status related to the scanner function and the copy function; and a switching power supply circuit for supplying power to the motor, the recording head, the scanner, and the display means. Is an operation mode for operating any one of the printer function, the scanner function, and the copy function. And supplying a control signal to the switching power supply circuit in accordance with a standby mode state in which the printer function, the scanner function, and the copy function are not operating, and a part of the operation mode and the standby mode. In the state, the operation of the switching power supply circuit is switched to the current mode feedback control by the control signal and controlled to be supplied to the power of each part of the device, and in a part of the standby mode, And switching the operation of the switching power supply circuit to open loop control or voltage mode feedback control according to the control signal, and controlling to stop a part of the power supply to the display means. A power supply control method is provided.

  Therefore, according to the present invention, voltage mode feedback control or open loop control is executed instead of the current mode feedback control used in the operation mode in a part of the standby mode. As a result, it is possible to achieve power supply at a higher accuracy voltage in the operation mode while achieving a further power saving effect in a part of the standby mode.

1 is an external perspective view showing an outline of the configuration of a multifunction printer apparatus (MFP apparatus) that is a typical embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of the MFP apparatus illustrated in FIG. 1. 2 is a block diagram showing a configuration of a power supply unit of MFP apparatus 100. FIG. 2 is a diagram illustrating a configuration of an operation unit 91 of the MFP apparatus 100. FIG. 1 is a circuit diagram showing a configuration of a switching power supply according to Embodiment 1. FIG. It is a figure which shows the principal part of control IC1A of FIG. 5 in detail. It is a figure which shows the relationship of each factor related to the open loop control shown in FIG. It is a figure which shows the PWM waveform produced | generated by the open loop control part 40A. It is a figure which shows the relationship between PWM parameters as a table | surface form. It is a figure which shows the example of a PWM waveform when input voltage is Vac = 100V and Vac = 200V. 3 is a diagram illustrating a relationship between an operation sequence of the MFP apparatus 100 and a state of a display or a control signal. FIG. FIG. 6 is a diagram showing a configuration of a switching power supply circuit according to a second embodiment. It is a circuit diagram which shows the detail of control IC1B of FIG. It is a time chart which shows the mode of operation | movement of the voltage mode control part 50 of the circuit shown in FIG. It is a circuit diagram which shows the example of the switching power supply by the conventional flyback system. FIG. 16 is a signal waveform diagram showing voltage and current waveforms of each part of the switching power supply circuit shown in FIG. 15. It is a figure which shows the principal part of control IC1 of FIG. 15 in detail. It is a time chart of a PWM signal and an output signal of an oscillator. FIG. 16 is a diagram illustrating a state in which intermittent oscillation operation is performed in the circuit of FIG. 15. It is a figure which shows a mode that the control mode of control IC1 is determined corresponding to the feedback voltage _VFB . It is a figure which shows an example of the technique which reduces a switching frequency according to the fall of load electric power.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (hereinafter also referred to as “printing”) is not only for forming significant information such as characters and figures, but also for images on a wide range of recording media, regardless of significance. A case where a pattern, a pattern, or the like is formed or a medium is processed is also expressed. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  The term “ink” should be broadly interpreted in the same way as the definition of “recording”. When applied to a recording medium, the “ink” forms an image, a pattern, a pattern, or the like, or processes the recording medium. It represents a liquid that can be subjected to the treatment. Examples of the ink treatment include solidification or insolubilization of the colorant in the ink applied to the recording medium.

  Furthermore, unless otherwise specified, the “recording element” collectively refers to an ejection port or a liquid path communicating with the ejection port and an element that generates energy used for ink ejection.

  First, the configuration of a multifunction printer apparatus (multifunction printer apparatus) (hereinafter referred to as MFP apparatus) used as a common embodiment will be described.

<MFP device>
FIG. 1 is a schematic perspective view of an MFP apparatus 100 according to a typical embodiment of the present invention.

  In addition to recording an image on a recording medium such as recording paper based on image data from a connected host (not shown), the MFP apparatus records and image originals based on image data stored in a memory card or the like. Can be read and copied.

  In FIG. 1, (a) shows a state in which the document cover 3 is closed, and (b) shows a state in which the loading tray 1, the paper discharge tray 2, and the document cover 3 of the recording medium are opened. Yes. A reading unit 72 including a contact image sensor (CIS) unit reads an image original and outputs analog luminance signals of R component, G component, and B component. For example, the card interface 9 is used to insert a memory card or the like on which an image file recorded by a digital still camera (not shown) is recorded, and read image data from the memory card according to a predetermined operation of the operation unit 91. used. The MFP apparatus 100 is provided with a display unit such as an LCD 92. The LCD 92 is used for display of setting contents by the operation unit 91 and display of a function selection menu.

  FIG. 2 is a block diagram illustrating a functional configuration of the MFP apparatus 100.

  As described above, recent ink jet recording apparatuses (hereinafter referred to as recording apparatuses) tend to be multifunctional, and have an image reading function as a scanner, a recording function as a printer, and a copying function as a copier. .

  In order to achieve these functions, as shown in FIG. 2, the MFP apparatus 100 is functionally roughly divided into a reading unit 72, a printing unit 73, and a control unit 74. When used as a scanner, read data 76 is transferred from the reading unit 72 to the external PC 75 via the control unit 74. On the other hand, when used as a printer, print data 77 is transferred from the PC 75 to the print unit 73 via the control unit 74. Further, when used as a copier, the data read by the reading unit 72 is transferred to the printing unit 73 via the control unit 74. Note that the detailed processing of such data does not correspond to the gist of the present invention, and thus the description thereof is omitted here.

  FIG. 3 is a block diagram illustrating a configuration of the power supply unit of the MFP apparatus 100.

  The power supply 82 is a universal power supply compatible with an input voltage of 100 V to 240 V via a power plug 81. The power supply unit 82 generates a DC output voltage indicated as Vo (DC24V). Here, Vo is an output with high accuracy, for example, ± 1% accuracy used for driving the ink jet recording head 83, and at the same time, a carriage such as a DC motor 86 or a stepping motor 87 is scanned to convey a recording medium. Also used for drive trains.

  Further, the output voltage Vo is also supplied to the DC-DC converter 85 and used to generate a plurality of logic system voltages. Such logic system voltages include, for example, DC 1.5V used as a core voltage of a CPU or ASIC, DC 3.3V supplied to an ASIC input / output unit (I / O) or a memory device, sensors, a display, etc. DC5V supplied to the power supply is included.

  In addition, when the MFP apparatus 100 is in the standby mode, the power supply unit 82 receives the energy saving control signal 88 to sufficiently reduce the standby power. As will be described later, the standby mode includes a state in which indicators such as an LCD and an LED lamp are lit (standby state), a state in which only some of the indicators are lit and the rest are turned off (sleep state), Furthermore, there is a state where all the indicators are turned off (power off state).

  Next, the standby mode will be described with reference to FIG.

  FIG. 4 is a diagram illustrating a configuration of the operation unit 91 of the MFP apparatus 100.

  The operation unit 91 includes an LCD 92. When a function such as a scanner function, a printer function, or a copy function is selected by the function selection buttons 93 to 95, various information and operation states corresponding to the function are displayed. Is displayed. Such information includes, for example, an illustration depicting each selected function, a number display set by the copy number setting button 96 when the copy function is selected, and the current MFP apparatus. 100 includes information on the size of the recording paper loaded in 100.

  The operation unit 91 further includes a clear button 97 for resetting the set copy number, a start button 98 for instructing to start a copy operation or a scanner operation, and a stop button 99 for stopping the copy operation or the scanner operation halfway. Also included are a power button 102 for instructing power on / off and a power lamp 101 that is turned on when the power is turned on and turned off when the power is turned off.

  In the MFP apparatus 100, both the LCD 92 and the power lamp 101 are lit when any of the operation modes of the scanner function, the printer function, or the copy function is being executed, and both the indicators are lit even in the standby state. . In the operation mode and standby state, a CPU, an ASIC (not shown), and the like are also operated at a steady speed in order to control the LCD.

  On the other hand, in the sleep state described above, the LCD 92 is turned off and only the power lamp 101 is turned on. In the power off state, both the LCD 92 and the power lamp 101 are turned off. Therefore, in the sleep state and the power-off state, it is possible to save energy by reducing the clock speed of the CPU or ASIC.

  As a result, the power consumption of the MFP apparatus 100 is several tens of watts during the operation mode in which power is supplied to each part of the apparatus, each state in the standby mode, that is, 2 to 5 W in the standby state, and about 1 W in the sleep state. When off, it is about 0.5W. An object of the present invention is to further reduce power consumption particularly in the standby mode, particularly in the above-described sleep state and power-off state.

  Next, an embodiment of a switching power supply circuit that supplies power to each unit of the recording apparatus having the above configuration will be described.

  FIG. 5 is a circuit diagram showing the configuration of the switching power supply circuit. Note that. In FIG. 5, the same components (for example, the switching element Q1) and signals as those described in the above-described conventional switching power supply of FIG. 15 are denoted by the same reference numerals and the same reference symbols, and the description thereof is omitted.

  As can be seen by comparing FIG. 5 and FIG. 15, the difference from the conventional circuit shown in FIG. 15 is as follows.

  That is, the switching power supply of this embodiment includes an energy saving circuit 17A that operates in the energy saving mode, that is, in the sleep state and the power off state. 5 is the same as the conventional circuit shown in FIG. 15 except for the energy saving circuit 17A. However, the control IC 1A has a separate function for processing the mode signal (MODE) 21, which will be described in detail with reference to FIG.

  When the MFP apparatus 100 is executing in the operation mode or in the standby state, in the energy saving circuit 17A, the energy saving control signal (Cont) 20 becomes high level, the transistor Q4 is turned on, and as a result, the transistor Q3 is also turned on, and the IC 2 operates. It becomes possible. Thereby, the feedback circuit 14 becomes effective. Further, the photocoupler IC4 is also turned on, the phototransistor 19 is turned on, the mode signal (MODE) 21 becomes low level, and the control IC 1A recognizes the execution instruction of the current mode control described above. The energy saving control signal (Cont) 20 is the energy saving control signal 88 described with reference to FIG. 3 and is supplied from the CPU of the control unit 74 of the MFP apparatus 100.

  On the other hand, when the energy saving control signal (Cont) 20 is at a low level, the transistor Q4 is turned off. As a result, the transistor Q3 is also turned off, the feedback circuit 14 is disabled, and the power consumption in this portion becomes zero. Instead, the photocoupler IC4 is turned off, the mode signal (MODE) 21 becomes high level, and the control IC 1A recognizes the energy saving mode. As a result, as described later, the operation mode is switched from the current mode feedback control to the open loop control.

  Next, open loop control according to this embodiment will be described with reference to FIG.

  FIG. 6 is a diagram showing in detail a main part of the control IC 1A of FIG. In FIG. 6, the same elements as those in FIGS. 5 and 15 are denoted by the same reference numerals. In FIG. 6, a portion added in connection with the open loop control is shown within a broken line 40.

  First, an outline of the circuit shown in FIG. 6 will be described.

  Based on the mode signal (MODE) 21, the control IC 1A selects either the current mode control output or the open loop control output as its output. That is, when the mode signal (MODE) 21 is at a low level, the output (PWM output 32 by current mode control) of the PWM circuit 20 (see FIG. 17) that performs PWM control is selected by the inverter 42 and the AND gate 41. Then, the signal is output to the output terminal (DRV) 34 through the OR gate 47 and the current drive gate 33. On the other hand, when the mode signal (MODE) 21 is at a high level, the PWM output 48A generated by the open loop control unit 40A is output to the output terminal (DRV) via the AND gate 43, the OR gate 47, and the current drive gate 33. 34.

  Next, the open loop control unit 40A will be described.

  As shown in FIG. 6, the open loop control unit 40 </ b> A includes three blocks including a Vin detection unit 46, a PWM parameter setting unit 47 </ b> A, and a PWM generation unit 48. In the standby mode, particularly in the sleep state and the power-off state, since the load fluctuation is generally smaller than that in the operation mode, the output voltage can be stabilized with a certain degree of accuracy even in the open loop control.

  FIG. 7 is a diagram showing the relationship of each factor related to the open loop control shown in FIG.

These factors include the input voltage Vac, the voltage Vin after rectification and smoothing, the inductance L ₁ (see FIG. 15) of the primary winding 11 of the transformer, and the PWM output turn-on time Ton. These factors are related by the following relational expression. That is,
Ip = (Vin / L ₁ ) * Ton (3)
It is.

When the above equation (3) is substituted into the above equation (2), the energy P ₂ generated per unit time by the transformer is obtained as follows. That is,
P ₂ = 1/2 * L ₁ * (Vin * Ton) ² * f * η (4)
It is.

By the way, in order to keep the output voltage Vo constant under a specific load condition, it is necessary to keep the energy P ₂ constant. Here, L ₁ is a fixed value depending on the transformer specification, and assuming that the frequency f is constant, the product of Vin and Ton may be kept constant in order to keep the energy P ₂ constant. I understand.

  From the above, as shown in FIG. 7, for example, if the PWM turn-on time when the input voltage Vac = 100V is Tref, the PWM turn-on time when the input voltage Vac = 200V is half of that, 0 .5 * Tref. Incidentally, as will be apparent to those skilled in the art, Vin is a value of √ (2) times the input voltage Vac.

  As apparent from the above, if the power consumption in the standby mode is known in advance, Ton is uniquely determined in accordance with the specific Vin value using the above equation (4). In order to realize this in a circuit, as shown by an open loop control unit 40A in FIG. 6, a PWM detection unit 46 and a PWM parameter setting unit 47A for determining PWM parameters, that is, Ton and Toff based on the Vin value, and a PWM The generation unit 48 is required. Ton is a turn-on time, Toff is a turn-off time, and Ton and Toff are duty ratios.

These blocks 46 to 48 generate a PWM waveform as shown in FIG. In FIG. 8, a waveform 132 is a PWM waveform when the input voltage Vac = 100V, and a waveform 133 is a PWM waveform when the input voltage Vac = 240V. As can be seen from FIG. 8, the Ton time when the input voltage Vac = 240V is 0.41 times that when the input voltage Vac = 100V. As apparent from the equation (4), since the energy P ₂ is proportional to the frequency f, the frequency of the PWM waveform in the standby mode may be lower than the frequency in the operation mode, for example, 60 KHz. However, in order to avoid an audible sound range, it is preferable to set to 20 to 30 KHz, for example.

Furthermore, the open loop control unit 40A of FIG. 6, in particular the PWM parameter setting unit 47A, is also possible by controlling another parameter related to PWM as shown in FIG. In Expression (4), when Ton is a fixed value, Expression (4) can be expressed as follows. That is,
P ₂ = 1/2 * L ₁ * Vin ² * Ton ² * f * η
= (1/2 * L ₁ * Von ² * η) * Vin ² * f
= C * Vin ² * f
= C * Vin ² * (1 / T) (5)
It is.

Here, C is a constant indicating (1/2 * L ₁ * Von ² * η). From equation (5), the energy P ₂ increases in proportion to the square of Vin and the frequency f. Therefore, in order to keep P ₂ constant, it is necessary to keep Vin ² * f constant.

  For example, when Vin doubles, the frequency f must be reduced by a factor of four. In other words, since the frequency f and the period T are in a reciprocal relationship, the period T is quadrupled.

  The relationship between the PWM parameters described above is shown in the table shown in FIG. 9, and examples of PWM waveforms when the input voltages are Vac = 100V and Vac = 200V are shown in FIG.

As is apparent from FIG. 10, paying attention to both cycles, the PWM cycle T ₂₀₀ when the input voltage Vac = 200V is four times the cycle T ₁₀₀ when the input voltage Vac = 100V. As a method of generating the waveform shown in FIG. 10, for example, a counter that counts the period T and a counter that counts the Ton time are prepared, or a counter that counts each of the time Ton and the time Toff is prepared. Possible methods.

  FIG. 11 is a diagram showing the relationship between the operation sequence of the MFP apparatus 100 and the states of the display and control signals described above with reference to FIGS. The control signal includes an energy saving control signal (Cont) 20 and a mode signal (MODE) 21 (see FIG. 5), and the state of the feedback circuit 14 (see FIG. 5) controlled by the energy saving control signal is also shown. On the other hand, the display includes a power lamp 101 and an LCD 92 (see FIG. 4).

  According to the embodiment described above, in the standby state and the operation mode, these indicators are in the active state, and the current mode feedback control is executed. On the other hand, in the power-off state and the sleep state, at least the LCD 92 (see FIG. 4) is inactive, and the control by the open loop is executed. In this way, it is possible to perform a certain output voltage with a certain degree of accuracy while achieving further power saving in the power-off state and the sleep state of the standby mode, and to control the output voltage with higher accuracy in the operation mode. be able to. Thereby, in any mode, it is possible to realize power supply control that satisfies the requirements in each mode.

  The configuration of the switching power supply circuit is not limited to the embodiment described above. In this embodiment, closed-loop voltage mode control will be described.

  FIG. 12 is a diagram illustrating a configuration of a switching power supply circuit according to the second embodiment. The feature of the circuit according to this embodiment is that an energy saving circuit 17B is provided instead of the energy saving circuit 17A, and an AUX signal 22 is further provided in the control IC 1B, as compared with the embodiment 1 in FIG. In FIG. 12, the same components as those in the switching power supply circuit shown in FIG. 5 already described are denoted by the same reference symbols or the same reference numerals, and the description thereof is omitted.

  Referring to FIG. 12, the AUX signal 22 is a signal obtained by dividing the rectified output voltage (auxiliary voltage) Vaux from the auxiliary winding 13 of the transformer T1 by the resistor R14 and the resistor R15. When the energy saving control signal (Cont) 20 is at a low level, the feedback circuit 14 is inactive, the photocoupler IC 4 is turned off, and the mode signal (MODE) 21 is at a high level. It is the same.

  FIG. 13 is a circuit diagram showing details of the control IC 1B of FIG. 12, and a closed loop voltage mode control unit, which is a feature of this embodiment, is indicated by a broken line 50. FIG. The other components are the same as those described in FIG. 6 of the first embodiment, and these are denoted by the same reference numerals.

  Here, the operation of the voltage mode control unit 50 will be described.

  In the standby mode, particularly in the sleep state and the power off state, the AUX signal 22 obtained by dividing the rectified output voltage Vaux is compared with the reference voltage 55 in the error amplifier 56. Here, the gain A of the error amplifier 56 is determined by the resistor 53 and the resistor 54 as gain A = R54 / R53. Next, the output 57 of the error amplifier 56 is compared with the reference signal 52 output from the reference signal generator (generation circuit) 51 by the comparator 58, and the PWM signal 58A is generated. The PWM signal 58A is then transmitted to the output terminal (DRV) 34 via the AND gate 43, the OR gate 47 and the current drive gate 33, as in the case of the circuit shown in FIG. Thus, feedback control is executed so that the voltage of the AUX signal 22 becomes equal to the reference voltage 55.

  As described above, the control shown in FIG. 13 compares the voltage Vaux generated by the auxiliary winding 13 of the transformer T1 shown in FIG. 12 with the reference voltage 55 and keeps the voltage Vaux at a constant voltage. Therefore, such control is called voltage mode feedback control. In a state where the load power fluctuation is small as in the standby mode, the voltage Vaux generated by the auxiliary winding 13 which is the primary winding of the transformer is controlled to be constant so that the voltage is generated by the secondary winding 12. It is possible to control the output voltage Vo with a certain degree of accuracy.

  FIG. 14 is a time chart showing how the voltage mode control unit 50 of the circuit shown in FIG. 13 operates.

  FIG. 14A shows the change over time of the voltage of the AUX signal 22 shown in FIGS. FIG. 14A shows the voltage state of the AUX signal at times t = t1, t2, and t3. FIG. 14B shows a state where the PWM signal 58A is generated by the voltage mode control unit 50 shown in FIG. Specifically, the reference signal 52 generated by the reference signal generator 51 and the voltage of the AUX signal 22 are compared by the comparator 58. Corresponding to each time, an output 192 of PWM (t1) is generated at time t = t1, and since the voltage of the AUX signal 22 increased at time t = t2, the ton time is shortened and PWM ( An output 193 of t2) is generated. Thereafter, at time t = t3, the voltage of the AUX signal 22 returns to the same level as at time t = t1, and the PWM output becomes the same as at time t = t1.

  In FIG. 14, the frequency of the reference signal 52 is preferably 20 to 30 KHz as in the first embodiment.

  Therefore, according to the embodiment described above, the output voltage Vo can be controlled with a certain degree of accuracy by the feedback control in the voltage mode in a state where the load power fluctuation is small as in the standby mode.

Claims (7)

A printer function for scanning a recording head by a motor to convey a recording medium and recording on the recording medium; a scanner function for scanning an image by reading a scanner; and reading the image original by the scanner; A multi-function printer that executes a copy function of copying a read image onto the recording medium,
Display means for displaying operation statuses related to the printer function, the scanner function, and the copy function;
A switching power supply circuit for supplying power to the motor, the recording head, the scanner, and the display means;
In accordance with an operation mode in which any one of the printer function, the scanner function, and the copy function is operated, and a standby mode in which the printer function, the scanner function, and the copy function are not operated, a control signal is transmitted. Control means for supplying power to the switching power supply circuit and controlling supply of power supplied from the switching power supply circuit to each unit of the device,
The switching power supply circuit is
According to the control signal, the operation of the switching power supply circuit is switched between open loop control or voltage mode feedback control and current mode feedback control,
The control means includes
In some states of the operation mode and the standby mode, the operation of the switching power supply circuit is switched to the feedback control of the current mode by the control signal, and is controlled to be supplied to the power of each part of the device,
In a part of the standby mode, the operation of the switching power supply circuit is switched to the open loop control or the feedback control of the voltage mode by the control signal to stop a part of the power supply to the display means. A multi-function printer apparatus, characterized in that In the standby mode state,
The display unit includes a state in which the display unit is turned on, a state in which only a part of the display unit is turned on and a remaining part is turned off, and a state in which all of the display unit is turned off. The multi-function printer apparatus according to 1. The switching power supply circuit is configured by a switching power supply that performs PWM control of the switching element,
The switching power supply circuit, for the open loop control,
Means for determining a PWM parameter for controlling the switching element from the value of the input voltage;
3. The multi-function printer according to claim 1, further comprising a unit that controls the switching element based on the PWM parameter determined by the determination unit.   4. The multifunction printer apparatus according to claim 3, wherein the PWM parameter is a turn-on time of a PWM signal or a duty ratio between the turn-on time and the turn-off time.   The multifunction printer apparatus according to claim 3, wherein the PWM parameter is a frequency or a period of a PWM signal. For the feedback control of the voltage mode, the switching power supply circuit
A transformer that generates an auxiliary voltage by the auxiliary winding of the primary winding;
A generating circuit for generating a reference voltage;
3. The multi-function printer according to claim 1, further comprising means for detecting the auxiliary voltage and performing feedback control so that the voltage is controlled to the reference voltage. A printer function for scanning a recording head by a motor to convey a recording medium and recording on the recording medium; a scanner function for scanning an image by reading a scanner; and reading the image original by the scanner; A power supply control method for a multi-function printer that executes a copy function of copying a read image onto the recording medium,
The multifunction printer device includes:
Display means for displaying operation statuses related to the printer function, the scanner function, and the copy function;
A switching power supply circuit that supplies power to the motor, the recording head, the scanner, and the display means;
The method
In accordance with an operation mode in which any one of the printer function, the scanner function, and the copy function is operated, and a standby mode in which the printer function, the scanner function, and the copy function are not operated, a control signal is transmitted. Supplying the switching power supply circuit;
In some states of the operation mode and the standby mode, a step of switching the operation of the switching power supply circuit to current mode feedback control by the control signal so as to be supplied to the power of each part of the device; ,
In some states of the standby mode, the operation of the switching power supply circuit is switched to open loop control or voltage mode feedback control by the control signal, and a part of power supply to the display means is stopped. A power supply control method comprising a step of controlling.

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