JP3450393B2 - Multiple output power supply - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for obtaining a plurality of outputs from one power supply transformer by feedback control.
The present invention relates to a recording apparatus using this power supply apparatus and a recording apparatus having a power supply for a control system, a drive system, and the like, and particularly to energy saving of these apparatuses. 2. Description of the Related Art (1) A recording apparatus has a control system power supply output for controlling a recording operation and a drive system power supply output for operating a power load such as a motor. When a plurality of outputs are performed using one power transformer, a technique of adding the voltage information of the plurality of outputs and performing feedback control on the current-on time on the primary side of the power transformer is used in order to guarantee voltage accuracy. ing. Hereinafter, this conventional example is referred to as Conventional Example 1. (2) In a recording apparatus such as a laser printer, a plurality of DC power supply outputs are supplied to a control system DC power supply (for example, +5 V) supplied to a control unit composed of a microprocessor (MPU) or the like. A drive system DC power supply (for example, +
24V). The operating state of this type of apparatus is roughly classified into two states, a recording operation state and a non-recording operation state. [0005] The recording operation state is a state in which an image is recorded by driving a motor or the like to convey a recording sheet in accordance with a recording command from an external device such as a personal computer. The non-recording operation state is a state in which the motor or the like is not driven and a recording command from an external device is awaited. Hereinafter, this conventional example is referred to as conventional example 2. (1) In a printing apparatus, when a printing operation is not performed, a load of a driving system power supply output is extremely small, and a voltage value accuracy is not required. However, in the conventional example 1, since a plurality of output voltages are fed back to the primary side of one power transformer for control, one of the power transformers is controlled so that the drive system power output always has a specified voltage value. The ON time of the secondary current is controlled. In the state where the recording operation is not performed, the primary current of the power supply transformer flows so that the drive system power supply output also becomes the specified voltage although the control system power supply output only needs to be the specified voltage. Iron loss and copper loss of the power transformer have increased, and the power efficiency of the recording apparatus has been extremely reduced. (2) Further, in the conventional example 2, a plurality of low-voltage DC power supplies are output regardless of the recording operation state and the non-recording operation state. However, in the non-recording operation state, there is no need to drive a motor or the like, so there is no need to output a drive system power supply. Therefore, the power consumed by the circuit for outputting the drive system DC power supply (within the low-voltage power supply) and the power consumed by unnecessary loads during the non-recording operation connected to the drive system DC power supply are wasted. Was. (3) The present invention has been made in such a situation, and an object of the present invention is to provide a multiple output power supply device and a recording device capable of preventing useless power consumption during a non-recording operation or the like. It is assumed that. [0011] To achieve the above object, according to an aspect of the multiple-output power supply unit according to the present invention to configure as the follows (1). (1) A power supply device used for a recording apparatus, which supplies power to a drive system circuit using one power supply transformer.
To be supplied to the first DC output V1 to be controlled and the control system circuit.
In multiple-output power supply device for obtaining a second DC output V2 to be a rectifier circuit for rectifying an AC power source, a switching means for turning on / off the application of the rectified output from the rectifier circuit to the primary side of the power transformer , The power transformer
Rectifies the output of the first secondary winding of the first DC output V
And a second rectifying means for generating a first
Rectifies the secondary winding output to generate the second DC output V2.
Second rectifying means, and the first and second DC outputs V
1, V2 and a feedback control means for performing feedback control by controlling said switching means based on, the feedback control means, on the basis of the both the first and second DC output V1, V2 A mode for controlling switching means, and a non-recording operation of the recording apparatus, wherein the first output is separated from a feedback control loop, so that the first output is not based on the first output, but based on the second output. A multiple output power supply device comprising switching means for switching between a mode for controlling the switching means and a mode for controlling the switching means. Hereinafter, the present invention will be described in more detail with reference to Examples. (Embodiment 1) FIG. 1 is a power supply circuit diagram of a "recording apparatus" of Embodiment 1. As a practical circuit, a filter circuit, a snubber circuit, and the like must be added, but are omitted here because they are not directly related to the present invention. In the figure, D1 is a diode bridge for full-wave rectification of an AC power supply. C1 is a smoothing capacitor. T1 is a transformer, and the number of turns of the primary winding is np, and the number of turns of the two secondary windings is n1 and n2, respectively. D2 and D3 are rectifier diodes that rectify the output of the n1 winding. L1 is a choke coil, and C2 is a smoothing capacitor. D4 and D5 are rectifier diodes, and n2
Rectify the output of the winding. L2 is a choke coil, C3
Is a smoothing capacitor. Q1 is a switching transistor which controls the current of the primary winding of the transformer T1 for power supply I
It is turned on / off by the output b of C · IC1. R1 and R2 are output voltage detecting resistors.
IC2 is a regulator IC, and the voltage across the resistor R3 is V
A current is caused to flow through the diode of the photocoupler PC1 so as to be ref, and the power supply control IC / IC1 controls the ON time of the transistor Q1 to keep the outputs V1 and V2 constant. Transistors Q2, Q3, resistors R4, R5, R6
R7 is a main part of the embodiment. The resistor R8 is a photocoupler P
This is the current limiting resistance of the diode C1. The operation of the circuit will be described. In the steady operation state, the energy saving mode signal S is at the low level, the transistor Q2 is turned on, and the transistor Q3 is turned on.
Is off. The loads of the outputs V1 and V2 have such values that the currents of the choke coils L1 and L2 satisfy the continuous condition. ## EQU1 ## The following relationship holds. T _ON is the time when the transistor Q1 is on, and T _OFF is the time when the transistor Q1 is on.
Is the time that is off. ## EQU2 ## The following holds. V _CE2 is the emitter-collector voltage of transistor Q2. The feedback control circuit for the outputs V1 and V2 comprises resistors R1, R2, R3,
It comprises a regulator IC / IC2, a photocoupler PC1, and a power supply control IC / IC1. Resistance R1, R2
Thus, the voltage values of the outputs V1 and V2 are added and fed back. The resistors R1 and R2 act as weights given to the feedback control of each output. That is, each output V1, V2
The degree of influence of the small fluctuation of the resistance on the feedback loop depends on the values of the resistors R1 and R2. Now, assuming that R1 / R2 = α, when α <1, the fluctuation of the output V1 mainly affects the feedback control. Output V when α> 1
2 mainly affects the feedback control. The value of α is determined by the accuracy of each output and the load fluctuation range. As shown in FIG. 2, an output V1 is a power supply output of a drive system circuit such as a motor, and V2 is a power supply of a control system circuit such as a CPU. Assume that the recording device has entered an energy saving mode state. The energy saving mode refers to a state in which the recording device is not accessed for a specified time or longer, and the load current is extremely reduced without refreshing, for example, a memory or the like of the control system circuit. In this case, the current continuous condition of the choke coils L1 and L2 is not satisfied. In this state, the energy saving mode control signal S is at a high level. Transistor Q
2 is turned off, and the transistor Q3 is turned on. When the transistor Q2 is turned off, the feedback loop of the output V1 is disconnected, and the voltage control loop becomes only the output V2 system. [Equation 3] Is established. Here, V _CE3 is the emitter-collector voltage of the transistor Q3. By selecting the value of R4 in the equation so as to be equal to the value of V2 in the equation, voltage feedback control of only the output V2 is established. At this time, when the load current of the output V2 is extremely reduced, the primary current of the transformer T1 decreases. That is, the ON time of the transistor Q1 becomes extremely short. At this time, the current of the choke coil L2 is not continuous, but the output V2 is kept constant by the capacitor C3. When the exciting current of the transformer T1 is extremely reduced, iron loss and copper loss are reduced, and the efficiency of the power supply circuit is significantly improved. In recent years, CPUs operating at a low voltage have become mainstream. When the control system power supply output voltage is 5 V, 3
When a CPU that can operate at V to 5 V is used, the CPU needs to operate at a high speed during the recording operation. The power supply voltage is 5 V, and the power supply voltage is 3 V in the energy saving mode (generally called sleep mode). By doing so, the power consumption of the power supply circuit can be further reduced. This function can be easily realized by selecting an appropriate value of R4 in the circuit diagram of FIG. As described above, in the recording apparatus, when the recording operation is not performed, the load of the driving system power supply output is extremely small and the voltage accuracy is not required. In the multiple output power supply, the constant voltage feedback control loop of the drive system power supply output was cut off, and only the control system power supply output was controlled at a constant voltage, and the excitation current of the power transformer could be extremely reduced to achieve energy saving. Become. (Embodiment 2) FIG. 3 is a power supply circuit diagram in a "recording apparatus" which is Embodiment 2. The overall configuration is Example 1
As shown in FIG. The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. OP1,
OP2 is an operational amplifier. For simplicity of description, the offset voltage of the operational amplifiers OP1 and OP2 is OV, and the emitter-collector voltage V _CE2 when the transistor Q2 is on is also OV. During the recording operation or in the steady state, the energy saving mode signal V _S is at the low level. At this time, The following holds. In the energy saving mode, the energy saving mode signal V _S becomes high level, and the following equation is established. (Equation 5) The voltage V2 determined by the equation:
In the first embodiment, the constants are selected so that the relationship with the voltage V2 'determined by
In the same manner as described above, power consumption can be reduced. (Embodiment 3) FIG. 4 is a sectional view for explaining the structure of a "laser printer" according to Embodiment 3. Hereinafter, the configuration and operation will be described. The laser printer main body 1 (hereinafter referred to as main body 1) has a cassette 2 for storing recording paper S, a cassette paper presence / absence sensor 3 for detecting the presence or absence of the recording paper S in the cassette 2, and a recording paper for the cassette 2. A cassette size sensor 4 (comprised of a plurality of micro switches) for detecting the size of S, and a paper feed roller 5 for feeding out recording paper S from the cassette 2
Etc. are provided. The recording paper S is located downstream of the paper feed roller 5.
Are provided synchronously.
An image forming unit 8 that forms a toner image on the recording paper S based on the laser beam from the laser scanner unit 7 is provided downstream of the registration roller pair 6. Further, a fixing unit 9 for thermally fixing the toner image formed on the recording sheet S is provided downstream of the image forming unit 8, and a sheet conveying state of a sheet discharging unit is provided downstream of the fixing unit 9. Sensor 10 for detecting paper discharge rollers 1 for discharging recording paper
1. Loading tray 12 for loading recording paper S on which recording has been completed
Is provided. Further, the laser scanner unit 7 outputs an image signal (image signal VD) sent from an external device 28 described later.
O), a laser unit 13 that emits a laser beam modulated based on O, a polygon motor 14 for scanning the laser beam from the laser unit 13 onto a photosensitive drum 17 described later, and a laser beam position in the scanning direction is detected. It comprises a beam detector 29, an imaging lens group 15, a folding mirror 16, and the like. The image forming section 8 includes a photosensitive drum 17, a pre-exposure lamp 18, a primary charger 19, a developing device 20, a transfer charger 21,
It is composed of a cleaner 22 and the like. The fixing unit 9 includes a heat roller 9a, a pressure roller 9b, a halogen heater 9c provided inside the heat roller, and a thermistor 9d for detecting the surface temperature of the heat roller. The main motor 23 is connected to the paper feed roller 5.
To the registration roller pair 6 via a registration roller clutch 25, and further to each unit of the image forming unit 8 including the photosensitive drum 17, the fixing unit 9, and the discharge unit. A driving force is also applied to the paper roller 11. Reference numeral 26 denotes a printer control device for controlling the main body 1, and includes a timer 26a, a ROM 26b,
It comprises an MPU (microcomputer) 26d having an AM 26c and the like, various input / output control circuits, and the like. Further, the printer control device 26 is communicably connected to an external device 28 via an interface 27. FIG. 5 shows the laser printer 1 shown in FIG.
3 is a block diagram showing details of the printer control device 26 in particular. FIG. In FIG. 5, when power is supplied from the commercial AC power supply 30 to the low-voltage power supply 31 in the printer control unit 26, the AC power supply is applied to the diode bridge 33 via the noise filter 32 and subjected to full-wave rectification. , Condenser 3
DC-D which is smoothed by 4 and outputs DC + 24V power
C converter 35, and DC for outputting DC + 5V power supply
Applied to the DC converter 36; The DC-DC converter 35 is a forward type converter, and monitors the DC output voltage to control the switching of the MOS-FET 35b, the transformer 35c, the diodes 35d, 35
e, a choke coil 35f, a capacitor 35g, etc., and output a stabilized DC + 24V. On the other hand, the DC-DC converter 36
The converter is a forward type converter. The stabilized DC + 5V composed of an oscillation control circuit 36a, a transformer 36c, diodes 36d and 36e, diodes 36d and 36e, a choke coil 36f, a capacitor 36g and the like which monitors the DC output voltage of the MOS-FET 36b and controls the switching is used. Output. The oscillation control circuit 35a in the DC-DC converter 35 has the RE output from the MPU 26d.
Mote signal is input and this signal is FALSE
, The switching control is forcibly stopped and DC + 2
The output of 4V is stopped. The +24 V output from the low-voltage power supply is supplied to the drive system load, the main motor 23 via the motor driver 37, the polygon motor 14 via the motor driver 38, the paper feed clutch 24 via the driver 39,
The registration clutch 25 via the driver 40, the pre-exposure lamp 18 via the driver 41, and the high voltage control circuit 42
Is supplied to The high voltage control circuit 42 supplies various high voltage power supplies to the primary charger 19, the developing device 20, the transfer charger 21.
To supply. On the other hand, the + 5V power supply includes a load other than the drive system, that is, the MPU 26d, a laser driver 43 for supplying a predetermined current to the laser unit 13, a beam detection circuit 44 for converting the current output of the beam detector 29 into a voltage, Input circuit 45 of paper ejection sensor 10, input circuit 4 of paper presence sensor 3
6, input circuit 47 of paper size sensor 4, drive circuit of halogen heater 9c in fixing unit 9, thermistor 9d
And a fixing circuit control circuit 48 including a safety circuit for preventing runaway of the halogen heater 9c. Further, the fixing device control circuit 48 is supplied with AC power for supplying to the halogen heater 9 c via the noise filter 32 in the low-voltage power supply 31. Here, all the loads are controlled by the MPU 26d. The printing operation in the configuration shown in FIGS. 4 and 5 will be described. Upon receiving a print command from the external device 28 via the interface 27, the MPU 26d drives the main motor 23 and the polygon motor 14, drives the paper feed clutch 24, and feeds out the recording paper S from the cassette 2. The fed recording paper S temporarily stops at the registration roller pair 6. On the other hand, the photosensitive drum 17 is also driven to rotate, is uniformly charged by the primary charger 19, and then is statically modulated by laser light from the laser scanner unit 7 (modulated based on image information from the external device 28). An electrostatic latent image is formed. This electrostatic latent image is converted into a visible image, that is, a toner image by the developing device 20, and is conveyed to a transfer area. In the transfer area, the toner image on the photosensitive drum 17 is transferred to the transfer charger 21.
Is transferred to the recording paper S by the action of. The recording paper S is conveyed by the registration roller pair 6 in synchronization with the toner image. When the transfer is completed, the recording paper S is conveyed to the fixing device 9, where the toner image is fixed, discharged to the stacking tray 12, and printing is completed. The photosensitive drum 17
The attached matter such as the residual toner on the upper surface is cleaned by a cleaner 22, and the photosensitive drum 17
In step 8, static elimination and initialization are performed, and the next image is formed (printed)
The process is ready to run. Next, according to the flowchart of FIG.
Control of the EMOTE signal will be described. First, it is determined whether or not there is a print instruction from the external device 28 (step S1). If there is a print instruction, a standby timer described later is stopped (step S2), and the REMOTE signal is set to TRUE (DC + 2).
(Output 4V power supply) (Step S3) The control is terminated. If there is no print instruction from the external device 28, RE
It is determined whether or not the Mote signal is TRUE (step S
4) If not TRUE, end the control. If TRUE, determine whether or not the standby timer (timer that counts up data in a predetermined area of the RAM 26c by using the timer 26a of the MPU 26d) is operating. (Step S5) If not in operation, the timer starts counting (Step S6). If in operation, it is determined whether or not the standby timer has timed out (the count value has reached a predetermined time). (Step S7),
If the time is not up, the control is terminated. If the time is up, the count of the standby timer is stopped (step S8), and the REMOTE signal is set to FALSE (DC + 24V output is stopped) to terminate the control. This control is always performed repeatedly. According to the above-described control, when the print instruction from the external device 28 is not given for a predetermined time or more, that is, when the standby state is continued for a predetermined time or more, the output of the DC + 24V power supply is stopped by setting the REMOTE signal to FALSE. , And the power consumed by the DC-DC converter 35 generating DC + 24 can be reduced to almost zero. As described above, in an image recording apparatus having a low-voltage power supply for obtaining a plurality of DC power supplies from a commercial AC power supply, during non-recording operation, the plurality of D
By providing a means for stopping a specific DC power output among C outputs, that is, a drive system DC power output for supplying electric power to a motor, a clutch, and the like not used during a non-recording operation,
This embodiment has the effect of preventing wasteful power consumption during non-recording operation (Embodiment 4). This embodiment has the same hardware configuration as Embodiment 3, and the external device 28 is connected to the M via the interface 27.
A "sleep state instruction" can be issued to the PU 26d. When the external device 28 determines that the print instruction is not required for a long time, the “sleep state instruction” is issued.
I do. FIG. 7 is a flowchart showing the control according to the "sleep state instruction". The MPU 26d determines whether or not there is a “sleep state instruction” from the external device 28 (step S1).
0), if there is no instruction of the sleep state, the REMOTE signal is set to TRUE (DC + 24V power is output) (step S11), and the temperature control of the fixing unit is started or continued (step S12), and the control is ended. Note that the temperature control of the fixing device is to control the fixing device to a predetermined temperature so that the printing operation can be performed immediately when a print instruction is issued. "Sleep state instruction" from external device 28
If there is, set the REMOTE signal to FALSE (D
The output of the C + 24V power supply is stopped (step S13),
The temperature control of the fixing device is stopped (step S14), and the control is ended. This control is always performed repeatedly. According to the above-described control, when printing is not performed according to an instruction from the external device 28, the power required for controlling the temperature of the fixing device and the power consumed by the driving system load such as the motor driver 37 are consumed. , And the power consumed by the DC-DC converter 35 generating DC + 24V can be reduced to almost zero. As described above, according to the present invention,
In a non-recording operation or the like, useless power consumption can be prevented.

[Brief description of the drawings] FIG. 1 is a circuit diagram of a power supply circuit according to a first embodiment. FIG. 2 is an electrical block diagram of the first embodiment. FIG. 3 is a circuit diagram of a power supply circuit according to a second embodiment. FIG. 4 is a sectional view of a third embodiment. FIG. 5 is a block diagram of a third embodiment; FIG. 6 is a flowchart illustrating the operation of the third embodiment. FIG. 7 is a flowchart showing the operation of the fourth embodiment.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hidenobu Suzuki               3-30-2 Shimomaruko, Ota-ku, Tokyo               Inside Canon Inc. (72) Inventor Tomoko Nambu               3-30-2 Shimomaruko, Ota-ku, Tokyo               Inside Canon Inc. (72) Inventor Yasumasa Nashida               3-30-2 Shimomaruko, Ota-ku, Tokyo               Inside Canon Inc. (72) Inventor Hiroshi Takazawa               3-30-2 Shimomaruko, Ota-ku, Tokyo               Inside Canon Inc. (72) Inventor Hiroshi Hashimoto               3-30-2 Shimomaruko, Ota-ku, Tokyo               Inside Canon Inc.                (56) References JP-A-1-269948 (JP, A)                 JP-A-2-101965 (JP, A)                 JP-A-62-178981 (JP, A)                 4-16 (JP, U)                 62-152683 (JP, U)

Claims (1)

(57) [Claim 1] A power supply device used for a recording apparatus, wherein a first DC output V1 to be supplied to a drive system circuit and a control using a single power supply transformer. In a multiple output power supply apparatus for obtaining a second DC output V2 to be supplied to a system circuit, a rectifier circuit for rectifying an AC power supply, and applying a rectified output from the rectifier circuit to a primary side of the power transformer. Switching means for turning off; first rectifying means for rectifying a first secondary winding output of the power transformer to generate the first DC output V1; and a second secondary winding output of the power transformer. Rectifying means for rectifying the second DC output V2, and feedback control for performing feedback control by controlling the switching means based on the first and second DC outputs V1 and V2. Means for controlling the switching means based on both the first and second DC outputs V1 and V2; and Is separated from the feedback control loop, without being based on the first output,
A multiple output power supply device, comprising: switching means for switching between a mode in which the switching means is controlled based on the second output.