JP5417313B2 - Power supply device, image forming apparatus - Google Patents

Description

  The present invention relates to a power supply device and an image forming apparatus.

  There are various apparatuses such as an image forming apparatus that have a sleep mode that suppresses power consumption of the apparatus and a normal mode that does not suppress power consumption of the apparatus.

  As this type of device, for example, devices in Patent Documents 1 to 3 exist.

  In the apparatus in Patent Document 1, in the energy saving mode for suppressing the power consumption of the main body, a main power source used in an operation mode in which the power consumption of the main body is not suppressed, and a commercial power source for inputting commercial AC power to the main power source. By turning off the relay circuit arranged between the AC power supply, the commercial AC power input to the main power supply is shut off.

  In the device in Patent Document 2, in the standby mode in which the power consumption of the main body is suppressed, the switching frequency of the switching power supply is set lower than that in the normal operation in which the power consumption of the main body is not suppressed.

  In addition, the apparatus in Patent Document 3 intermittently operates the switching power supply with the on-duty of the energy-saving pulse in the sleep mode in which the power consumption of the image forming apparatus is reduced.

JP 2002-10492 A JP 2000-1116027 A JP 2006-287429 A

  By the way, in the device in Patent Document 1, when the commercial AC power input to the main power source is interrupted in the sleep mode, the loss in the main power source is eliminated, so that the power consumption of the entire device can be suitably suppressed.

  However, in order to cut off the input of commercial AC power to the main power supply, a relay circuit or triac that cuts off the input of commercial AC power to the main power supply may be arranged between the commercial AC power supply and the main power supply. Necessary.

  In this case, since a large amount of commercial AC power is input to the relay circuit or triac, it is necessary to use a relay circuit or triac having a high withstand voltage, which increases costs.

  In the sleep mode, the operation of the switching power supply disposed in the main power supply may be stopped in order to cut off the supply of the operation power supply voltage from the main power supply.

  In this case, in the main power supply, current continues to flow through the noise filter provided in the previous stage of the switching power supply, resulting in loss. Therefore, compared with the case where the commercial AC power input to the main power supply is cut off, the overall power consumption Electric power increases.

  SUMMARY An advantage of some aspects of the invention is that it provides a power supply apparatus and an image forming apparatus capable of suitably reducing cost and power consumption of the entire apparatus.

A power supply apparatus according to an aspect of the present invention is a power supply apparatus that supplies an operation power supply voltage to an apparatus having a sleep mode that suppresses power consumption and a normal mode that does not suppress power consumption. A sleep power supply unit that supplies an operation power supply voltage to the device; a normal power supply unit that supplies the operation power supply voltage to the device in the normal mode; and a control unit. A noise filter for removing power noise, the line capacitor connected to a power supply line to which the commercial AC power is input, a discharge resistor connected in parallel to the line capacitor, and the discharge resistor a noise filter and a first switching unit connected between the power supply line, the quotient of the noise by the noise filter is removed Includes a power supply voltage generation unit for generating the operating power supply voltage based on the AC power, wherein the power supply voltage generation unit comprises: a diode bridge for rectifying the noise the commercial AC power has been removed by the noise filter, the A smoothing capacitor for smoothing commercial AC power rectified by a diode bridge and converting it to DC power, a transformer for transforming the DC power to a predetermined voltage value, and intermittently passing the DC power to the first primary winding of the transformer A switching element that outputs to
A normal control unit for controlling a duty ratio of a pulse signal output to the switching element so that the operating power supply voltage becomes the predetermined voltage value; a second primary winding of the transformer; and the second primary winding. A second switching unit connected in series to the power supply circuit, and a power supply circuit for generating a power supply voltage for operation of the normal control unit, wherein the control unit turns on the first switching unit in the normal mode In addition, the second switching unit is turned on, and the power supply voltage generation unit generates the operation power supply voltage. In the sleep mode, the first switching unit is turned off, and the second switching unit is turned on. It is turned off, and the generation of the operation power supply voltage by the power supply voltage generation unit is stopped.

  A discharge resistor connected in parallel to the line capacitor in the noise filter discharges the charge accumulated in the line capacitor. And since a discharge resistance becomes an actual load with respect to an input voltage, the power consumption of a discharge resistance is large compared with the other element in a noise filter.

According to this configuration, in the sleep mode in which the power consumption of the device is suppressed, the control unit turns off the first switching unit in the normal power supply unit to cut off the connection between the discharge resistor in the noise filter and the power supply line. At the same time, the generation of the operation power supply voltage by the power supply voltage generation unit is stopped.

  As a result, in the normal power supply unit, commercial AC power is no longer input to the discharge resistor, so there is no loss in the discharge resistor with the largest power consumption in the noise filter, and generation of the operation power supply voltage by the power supply voltage generation unit Is stopped, the loss in the power supply voltage generator is eliminated.

  For this reason, it is possible to suitably suppress power consumption without using a relay circuit or triac having a high withstand voltage. As a result, it is possible to suitably reduce cost and power consumption.

The said structure WHEREIN: It is preferable that the said 1st switching part is connected between the parallel circuit of the said line capacitor and the said discharge resistance, and the said power supply line.

According to this configuration, since the first switching unit is connected between the parallel circuit of the line capacitor and the discharge resistor and the power supply line, when the first switching unit is turned off in the sleep mode, The connection between the parallel circuit of the intermediate capacitor and the discharge resistor and the power supply line is cut off.

  Thereby, in the sleep mode, not only the discharge resistor but also the line capacitor is disconnected from the power supply line, so that the loss in the discharge resistor and the line capacitor is eliminated. As a result, it is possible to more appropriately reduce power consumption.

  Also, in the sleep mode, if the discharge resistor is disconnected from the line capacitor while the line capacitor and the power line are connected, the charging voltage of the line capacitor appears at the external input terminal of the power supply device. Absent.

  However, according to this configuration, since the parallel circuit of the line capacitor and the discharge resistor is separated from the power supply line, the charge accumulated in the line capacitor is discharged by the discharge resistor in the parallel circuit. Thereby, the charging voltage of the line capacitor does not appear at the external input terminal of the power supply device, which is preferable for safety.

  In addition, an image forming apparatus according to another aspect of the present invention includes the above-described power supply device, an image reading unit that reads image data of a document, and image formation that forms image data read by the image reading unit on a recording sheet. And a section.

  According to this configuration, since the power supply device described above is provided, it is possible to suitably reduce costs and power consumption of the entire device.

  According to the present invention, it is possible to suitably reduce costs and power consumption of the entire apparatus.

1 is a longitudinal sectional view schematically showing an example of a configuration of an image forming apparatus according to an embodiment of the present invention. It is the block diagram which showed an example of the functional module of the power supply device which concerns on one Embodiment of this invention. It is the flowchart which showed an example of the outline | summary of the basic operation | movement of a power supply device.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view schematically showing an example of the configuration of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus A in FIG. 1 includes the power supply device 1 (see FIG. 2) according to an embodiment of the present invention.

  The image forming apparatus A includes an image reading unit 200 and an image forming main body unit 3. The image reading unit 200 includes a document feeding unit 210, a scanner main body 220, a CIS 231, a user interface unit I disposed so as to be exposed on the front surface of the scanner main body 220, and a reversing mechanism described later.

  The document feeder 210 includes an ADF (Automatic Document Feeder), and includes a document tray 211, a pickup roller 212, a platen 213, a paper discharge roller 214, and a paper discharge tray 215.

  A document to be read is placed on the document tray 211. Documents placed on the document tray 211 are picked up one by one by the pickup roller 212 and sequentially conveyed to the platen 213 through the gap. Documents that have passed through the platen 213 are sequentially discharged to the discharge tray 215 by the discharge rollers 214.

  Of the positions facing the peripheral surface of the platen 213, a timing sensor (not shown) for detecting paper is installed at a predetermined position before the reading position P in the document transport direction. The document transport timing to the reading position P is achieved based on the output request. The timing sensor is configured by, for example, a photo interrupter.

  The scanner main body 220 optically reads image data of a document and generates image data. The scanner main body 220 includes a glass 221, a light source 222, a first mirror 223, a second mirror 224, a third mirror 225, a first carriage 226, a second carriage 227, an imaging lens 228, and a line sensor 229.

  In the scanner main body 220, the light emitted from the light source 222 is reflected by the original on the glass 221 to become reflected light, and this reflected light is used as the first mirror 223, the second mirror 224, the third mirror 225, and the first carriage. 226, the second carriage 227, and the imaging lens 228 are guided to the line sensor 229.

  The light guided to the line sensor 229 is converted by the line sensor 229 into charges representing image data.

  On the glass 221, a document is manually placed by the user when reading the document without using the document feeder 210. The light source 222 and the first mirror 223 are supported by the first carriage 226, and the second mirror 224 and the third mirror 225 are supported by the second carriage 227.

  As the document reading method of the image reading unit 200, the scanner body 220 reads a document placed on the glass 221 and the document is read by the document feeder 210 (ADF). There is an ADF reading mode for reading.

  In the flatbed reading mode, the light source 222 irradiates a document placed on the glass 221, and reflected light for one line in the main scanning direction is reflected in the order of the first mirror 223, the second mirror 224, and the third mirror 225. Then, the light enters the imaging lens 228. The light incident on the imaging lens 228 is imaged on the light receiving surface of the line sensor 229.

  The line sensor 229 is a one-dimensional image sensor, and processes the image data of one line of document in an overlapping manner. The first carriage 226 and the second carriage 227 are configured to be movable in a direction orthogonal to the main scanning direction (sub-scanning direction Y). When reading of one line is completed, the first carriage 226 is moved in the sub-scanning direction. Then, the second carriage 227 moves and the next line is read.

  In the ADF reading mode, the document feeder 210 takes in the documents placed on the document tray 211 one by one by the pickup roller 212. At this time, the first carriage 226 and the second carriage 227 are disposed below a predetermined reading position P positioned below the reading window 230.

  When the document is transported by the document feeder 210, when the document passes over the reading window 230 provided in the transport path from the platen 213 to the paper discharge tray 215, the light source 222 irradiates the document, and the main scanning one line. The reflected light is reflected in the order of the first mirror 223, the second mirror 224, and the third mirror 225 and enters the imaging lens 228. The light incident on the imaging lens 228 is imaged on the light receiving surface of the line sensor 229. Subsequently, the document is conveyed by the document feeder 210 and the next line is read.

  Further, the document feeder 210 has a reversing mechanism including a switching guide 216, a reversing roller 217, and a reversing conveyance path 218. The reversing mechanism reverses the front and back of the original whose surface has been read by the first ADF reading and transports it again to the reading window 230, so that the line sensor 229 reads the back side again.

  This reversing mechanism operates only when reading both sides and does not operate when reading one side. After reading the back side during single-sided reading and double-sided reading, the switching guide 216 is switched to the upper side, and the document that has passed through the platen 213 is discharged to the discharge tray 215 by the discharge roller 214.

  After the front side reading at the time of double-sided reading, the switching guide 216 is switched to the lower side, and the document that has passed through the platen 213 is transported to the reverse transport path 218 by the reverse roller 217. Thereafter, the switching guide 216 is switched upward, and the reverse roller 217 rotates in the reverse direction to re-feed the document to the platen 213. Hereinafter, a mode in which both sides of a document are read using a reversing mechanism is referred to as a double-sided reversal reading mode.

  Further, in the ADF reading mode, the image reading unit 200 according to the present embodiment substantially overlaps when the line sensor 229 (scanner body 220) reads the surface of the document during the conveyance of the document as described above ( It is possible to read the back side of the document by the CIS 231 (substantially in parallel). In this case, the document conveyed from the document tray 211 by the document feeder 210 is read by the line sensor 229 when passing over the reading window 230 and further read by the back side when passing through the location where the CIS 231 is disposed. It is done. In CIS231, RGB three-color LEDs or the like are used as light sources.

  By using the line sensor 229 and the CIS 231 in this way, it is possible to read both the front and back sides of a document by a single document transport operation (one pass) from the document tray 211 to the paper discharge tray 215 by the document feeding unit 210.

  The image forming apparatus A includes an image forming main body 3 and a stack tray 6 disposed on the left side of the image forming main body 3. The image forming main body 3 has been transported from a plurality of paper feed cassettes 461, a paper feed roller 462 for feeding recording sheets from the paper feed cassette 461 one by one to the image forming unit 40, and a paper feed cassette 461. And an image forming unit 40 that forms image data on recording paper. In addition, the image forming main body 3 includes a paper feed tray 471 and a feeding roller 472 that feeds the originals placed on the paper feed tray 471 one by one toward the image forming unit 40.

  The image forming unit 40 removes the residual charge from the surface of the photosensitive drum 43, the charging device 422 that charges the surface of the photosensitive drum 43 after static elimination, and the image data acquired by the scanner main body 220. Based on the electrostatic latent image, an exposure device 423 that outputs a laser beam to expose the surface of the photosensitive drum 43 to form an electrostatic latent image on the surface of the photosensitive drum 43. Above, developing devices 44K, 44Y, 44M, and 44C that form toner images of cyan (C), magenta (M), yellow (Y), and black (K), and various colors formed on the photosensitive drum 43. A transfer drum 49 on which the toner image data is transferred and superimposed, a transfer device 41 for transferring the toner image on the transfer drum 49 to the paper, and heating the paper on which the toner image is transferred. And a fixing device 45 for fixing the toner image to the sheet.

  The cyan, magenta, yellow, and black colors are supplied from a toner cartridge (not shown). Further, conveyance rollers 463 and 464 that convey the recording paper that has passed through the image forming unit 40 to the stack tray 6 or the discharge tray 48 are provided.

  When forming image data on both sides of the recording paper, the image forming unit 40 forms image data on one side of the recording paper, and then the recording paper is nipped by the conveyance roller 463 on the discharge tray 48 side. To do. In this state, the conveyance roller 463 is reversed to switch back the recording paper, and the recording paper is sent to the paper conveyance path L and is conveyed again to the upstream area of the image forming unit 40. Then, the recording paper is discharged to the stack tray 6 or the discharge tray 48.

  The user interface unit I includes a display unit 5 and an operation unit 18. The operation unit 18 includes a power button (not shown), and, for example, a bi-directional power switch 19 shown in FIG. 2 is turned on / off in response to an on / off operation of the power button. When the power switch 19 is on, the power supply device 1 supplies the operation power supply voltage for the image forming apparatus A. When the power switch is off, the power supply device 1 stops supplying the operation power supply voltage.

  FIG. 2 is a block diagram showing an example of a functional module of the power supply device according to the embodiment of the present invention.

  The power supply device 1 includes a control unit 10, a sleep power supply unit 11, a normal power supply unit 12, and a power switch 19.

  The control unit 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The control unit 10 is realized when the CPU executes a predetermined control program.

  The control unit 10 operates by receiving an operation power supply voltage having a voltage value V3 from the sleep power supply unit 11. The control unit 10 has a sleep mode in which the power consumption of the image forming apparatus A is suppressed and a normal mode in which the power consumption of the image forming apparatus A is not suppressed.

  Here, the sleep power supply unit 11 specifically includes a noise filter 14, a diode bridge DB1, a smoothing capacitor C6, a transformer TR1, a switching element Q1, a diode D2, a smoothing capacitor C8, a sleep control unit 13, a detection circuit 15, and a diode. D1, a smoothing capacitor C7, and an external output terminal T3 connected to a connection point between the smoothing capacitor C8 and the diode D2.

  The normal power supply unit 12 includes a noise filter 17 having a switch SW1, a diode bridge DB2, a smoothing capacitor C14, a transformer TR2, a switching element Q2, a diode D4, a smoothing capacitor C16, a normal control unit (power supply voltage generation unit) 16, and a detection. An external output terminal having a circuit 18 and a switch SW2 and connected to a connection point between a power supply circuit B that generates an operation power supply voltage for the normal control unit 16, a DC-DC converter 20, a smoothing capacitor C16, and a diode D4 T1 and an external output terminal T2 connected to the voltage output terminal of the DC-DC converter 20 are provided.

  The control unit 10 performs on / off control of the switches SW1 and SW2. The controller 10 turns off the switches SW1 and SW2 in the sleep mode, and turns on the switches SW1 and SW2 in the normal mode.

  In both the normal mode and the sleep mode, the sleep power supply unit 11 supplies an operation power supply voltage having a voltage value V3 (for example, 5 V) to a portion of the image forming apparatus A that operates using the voltage value V3 as a power supply voltage.

  Here, the portion to which the operation power supply voltage of the voltage value V3 is to be supplied by the sleep power supply unit 11 needs to operate in both the normal mode and the sleep mode, and the operation power supply voltage is large enough to operate. For example, the control unit 10 and the network interface can be mentioned.

  In the normal mode, the normal power supply unit 12 supplies an operation power supply voltage having a voltage value V1 (for example, 24V) to a portion of the image forming apparatus A that operates using the voltage value V1 as a power supply voltage. Further, in the normal mode, the normal power supply unit 12 supplies an operation power supply voltage having a voltage value V2 (for example, 5 V) smaller than the voltage value V1 to a portion that operates using the voltage value V2 as a power supply voltage.

  Here, the part to which the normal power supply unit 12 is to be supplied with the operation power supply voltage having the voltage value V1 does not need to operate in the sleep mode, but requires an operation power supply voltage larger than the voltage value V2 to operate. For example, a motor.

  The portion to which the operation power supply voltage of the voltage value V2 is to be supplied from the normal power supply unit 12 does not need to operate in the sleep mode, but does not require an operation power supply voltage as large as the voltage value V1 to operate. For example, a print control unit that controls image forming processing in the image forming apparatus A can be used.

  The power switch 19 is a switch for turning on / off the input of commercial AC power from the commercial AC power source to the normal power source unit 11 and the sleep power source unit 12. Specifically, the power switch 19 is on a power line L to which commercial AC power is input, and is a double-sided switch disposed between the commercial AC power AC and the normal power source 11 and the sleep power source 12. It consists of

  In the sleep power supply unit 11, the noise filter 14 removes noise of commercial AC power input from the commercial AC power supply AC through the power supply line L. The diode bridge DB1 rectifies commercial AC power from which noise has been removed by the noise filter 14.

  The smoothing capacitor C6 is made of an electrolytic capacitor, and smoothes commercial AC power rectified by the diode bridge DB1. The transformer TR1 transforms the voltage of the commercial AC power smoothed by the smoothing capacitor C6 to a predetermined voltage value. Switching element Q1 causes commercial AC power smoothed by smoothing capacitor C6 to be input to primary side winding W1 of transformer TR1 at a predetermined period.

  The diode D2 rectifies commercial AC power whose voltage value is transformed by the transformer TR1 and output through the secondary winding W3. The smoothing capacitor C8 is made of an electrolytic capacitor and smoothes commercial AC power rectified by the diode D2.

  The sleep control unit 13 controls the sleep power supply unit 11. The detection circuit 15 detects the voltage across the smoothing capacitor C8. The diode D1 and the smoothing capacitor C7 are arranged to generate a power supply voltage for operation of the sleep control unit 13.

  In the sleep power supply unit 11, two primary windings W1 and W2 are wound on the primary side of the transformer TR1, and one secondary winding W3 is wound on the secondary side. .

  The commercial AC power smoothed by the smoothing capacitor C6 is intermittently input to the primary winding W1 by PWM control of the switching element Q1, and the voltage of the commercial AC power intermittently input to the primary winding W1. Is transformed by the transformer TR1, and the transformed voltage appears in the secondary winding W3.

  As a result, the voltage transformed by the transformer TR1 appears intermittently in the secondary side winding W3, and the voltage intermittently appearing in the secondary side winding W3 is separated from the primary side winding W2 by the transformer TR1. The voltage is transformed according to the turn ratio with the secondary winding W3, and the transformed voltage appears in the primary winding W2.

  As a result, the transformed voltage appears intermittently in the primary winding W2, so that the voltage intermittently appearing in the primary winding W2 is rectified by the diode D1 and then smoothed by the smoothing capacitor C7. The As a result, the operating power supply voltage Vcc for the sleep control unit 13 is generated and input to the sleep control unit 13. Thereby, the sleep control unit 13 operates.

  The sleep control unit 13 includes a CPU, a RAM, a ROM, and the like. The sleep control unit 13 is realized by the CPU executing a predetermined control program.

  The sleep controller 13 controls the switching element Q1 by PWM (Pulse Width Modulation). The sleep control unit 13 refers to the voltage across the smoothing capacitor C8 detected by the detection circuit 15 as the reference voltage Vref, and outputs it to the switching element Q1 so that the voltage value of the reference voltage Vref becomes the voltage value V3. Controls the duty ratio of the pulse signal.

  As a result, since the operation power supply voltage having the voltage value V3 is output to the external output terminal T3 of the sleep power supply unit 11, the sleep power supply unit 11 supplies the operation power supply voltage having the voltage value V3 through the external output terminal T3. Supply.

  In the sleep power supply unit 11, the noise filter 14 can be configured by using a known noise filter.

  Specifically, the noise filter 14 is connected in parallel to the line capacitor C1 connected between the two power supply lines L and the line capacitor C1 and discharges the electric charge accumulated in the line capacitor C1. A series circuit of line bypass capacitors C2 and C3 arranged between the resistor R1 and the two power supply lines L, and arranged between the line capacitor C1 and the discharge resistor R1, and the power supply line L to connect the line bypass A common mode choke coil CC1 disposed downstream of the capacitors C2 and C3 and a series circuit of line bypass capacitors C4 and C5 disposed between the two power supply lines L and disposed downstream of the common mode choke coil CC1; .

  The connection point between the line bypass capacitors C2 and C3 and the connection point between the line bypass capacitors C4 and C5 are grounded.

  In the noise filter 14, the line capacitor C <b> 1 is a so-called X capacitor and suppresses normal mode noise of commercial AC power input to the power supply line L. Further, the discharge resistor R1 prevents the charge voltage of the line capacitor C1 from appearing at the external input terminal of the power supply device 1 when, for example, the power switch 19 is turned off by discharging the charge of the line capacitor C1. Functions as a bleeder resistor.

  Furthermore, the line bypass capacitors C2 to C5 are so-called Y capacitors and suppress common mode noise of commercial AC power input to the power supply line L. Furthermore, the common mode choke coil CC1 suppresses common mode noise of commercial AC power input to the power supply line L.

  In the sleep power supply unit 11 having this configuration, the noise is removed from the commercial AC power supplied through the power line L by the noise filter 14, and the commercial AC power after the noise is rectified by the diode bridge DB1, and the commercial AC after rectification The electric power is smoothed by the smoothing capacitor C6. Thereby, commercial AC power is converted into DC power.

  The DC power obtained by the diode bridge DB1 and the smoothing capacitor C6 is intermittently output to the primary winding W1 of the transformer TR1 at the timing when the switching element Q1 is turned on.

  Here, the on-duty of the pulse signal output to the switching element Q1 is controlled by the sleep control unit 13 so that the voltage value of the operation power supply voltage supplied from the sleep power supply unit 11 becomes the voltage value V3. Yes.

  The DC power intermittently output to the primary side winding W1 of the transformer TR1 is used for the turn ratio of the primary side winding W1 and the secondary side winding W3 of the transformer TR1, the on-duty of the switching element Q1, etc. Accordingly, the transformed DC power is output from the secondary winding W3 of the transformer TR1. Thereby, the transformed DC power is intermittently output from the secondary side of the transformer TR1.

  Then, the DC power intermittently output from the secondary side of the transformer TR1 is rectified by the diode D2, the rectified power is smoothed by the smoothing capacitor C8, and the operating power source having the voltage value V3 is obtained by the smoothed power. The voltage appears at the external output terminal T3 of the sleep power supply unit 11. As a result, the operation power supply voltage having the voltage value V3 is supplied.

  On the other hand, in the normal power supply unit 12, the functions of the switch SW1, the power supply circuit B, the normal control unit 16, and the DC-DC converter 20 are as follows.

  The normal control unit 12 is the same as the sleep power supply unit 11 except for the switch SW1, the power supply circuit B, the normal control unit 16, and the DC-DC converter 20, and a description thereof will be omitted.

  The switch SW1 is arranged between the parallel circuit of the line capacitor C9 and the discharge resistor R2 and the power supply line L, and turns on and off the input of commercial AC power to the parallel circuit. The switch SW1 is on / off controlled by the control unit 10. The control unit 10 turns off the switch SW1 in the sleep mode, and turns on the switch SW1 in the normal mode.

  The power supply circuit B is a power supply circuit that generates a power supply voltage for operation of the normal control unit 16. In the power supply circuit B, the primary side winding W2, the diode D3, and the switch SW2 of the transformer TR2 are connected in series. A smoothing capacitor C15 is connected in parallel with the series circuit of the primary side winding W2 of the transformer TR2 and the diode D3, and the power supply circuit B is configured.

  The voltage across the smoothing capacitor C15 is supplied as the power supply voltage Vcc to the normal control unit 16 via the switch SW2.

  The switch SW2 is ON / OFF controlled by the control unit 10, and the control unit 10 turns off the switch SW2 in the sleep mode and turns on the switch SW2 in the normal mode.

  The normal control unit 16 includes a CPU, a RAM, a ROM, and the like. The normal control unit 16 is realized by the CPU executing a predetermined control program.

  The normal control unit 16 detects the pulse signal output to the switching element Q2 so that the voltage value detected by the detection circuit 18, that is, the voltage value output from the external output terminal T1 becomes the voltage value V1. Control the duty ratio. As a result, the operating power supply voltage having the voltage value V1 is supplied from the external output terminal T1 of the normal power supply unit 12 to each unit of the image forming apparatus A that should operate in the normal mode.

  The DC-DC converter 20 steps down the voltage across the smoothing capacitor C16 to the voltage value V2, and outputs the voltage value V2 to the external output terminal T2. As a result, an operating power supply voltage having a voltage value V2 different from the voltage value V1 is supplied from the external output terminal T2 of the normal power supply unit 12 to each part of the image forming apparatus A that should operate in the normal mode.

  In the normal power supply unit 12 having such a configuration, when the control unit 10 is in the normal mode, the switch SW1 is on, so that commercial AC power is input to the line capacitor C9, and the normal mode noise of the commercial AC power is input by the line capacitor C9. Is suppressed.

  Further, since the switch SW2 is on, the normal control unit 16 operates, and the normal control unit 16 controls on / off of the switching element Q1 so that the output voltage from the external output terminal T1 becomes the voltage value V1.

  As a result, the operation power supply voltage having the voltage value V1 is output from the external output terminal T1, and the operation power supply voltage having the voltage value V2 is output from the external output terminal T2.

  Accordingly, the operation power supply voltage having the voltage value V1 and the operation power supply voltage having the voltage value V2 are supplied to each unit of the image forming apparatus A.

  On the other hand, when the control unit 10 is in the sleep mode, since the switch SW1 is off, commercial AC power is not input to the parallel circuit of the line capacitor C9 and the discharge resistor R2 in the noise filter 17.

  Here, since the discharge resistor R2 becomes an actual load with respect to the input voltage, the power consumption of the discharge resistor R2 is larger than the other elements in the noise filter 17. In the sleep mode, commercial AC power is not input to the parallel circuit of the line capacitor C9 and the discharge resistor R2, so that the loss in the discharge resistor having the largest power consumption in the noise filter 17 is eliminated.

  Further, when the control unit 10 is in the sleep mode, the switch SW2 is off, so that the supply of the operation power supply voltage to the normal control unit 16 is interrupted. As a result, the operation of the normal control unit 16 stops, and the supply of the operation power supply voltage to the image forming apparatus A by the normal power supply unit 12 is cut off. As a result, the operation of each part of the image forming apparatus A that has been operating in the normal mode is stopped, so that the power consumption of the image forming apparatus A is smaller than the power consumption in the normal mode.

  Furthermore, since the operation of the normal control unit 16 is stopped when the control unit 10 is in the sleep mode, the loss in the normal control unit 16 is eliminated.

  Therefore, the power consumption in the sleep mode can be suitably suppressed without using a relay circuit or triac having a high withstand voltage for cutting off the primary side input voltage to the normal power supply unit 12. As a result, it is possible to suitably reduce cost and power consumption.

  Furthermore, in the sleep mode, commercial AC power is not input not only to the discharge resistor R2 but also to the line capacitor C9, so that there is no loss in the discharge resistor R2 and the line capacitor C9. As a result, it is possible to more appropriately reduce power consumption.

  Furthermore, in the sleep mode, the parallel circuit of the line capacitor C9 and the discharge resistor R2 is disconnected from the power supply line L. Therefore, in the parallel circuit, the charge accumulated in the line capacitor C9 is discharged by the discharge resistor R2. Thereby, since the charging voltage of the line capacitor C9 does not appear at the external input terminal of the power supply device 1, it is preferable for safety.

  In this embodiment, the switch SW1 and the parallel circuit of the line capacitor C9 and the discharge resistor R2 are connected in series between the two power lines L. However, the present invention is not limited to this example. A line capacitor C9 may be connected between the two power supply lines L, and a series circuit of the switch SW1 and the discharge resistor R2 may be connected next to the line capacitor C9 in parallel with the line capacitor C9. .

  FIG. 3 is a flowchart showing an example of an outline of the basic operation of the power supply apparatus. As a premise for the following processing, it is assumed that the mode of the control unit 10 is the normal mode.

  When it is time to shift to the sleep mode (YES in step S1), the control unit 10 shifts to the sleep mode (step S2). In addition, as a timing which should transfer to sleep mode, the time when the operation part 18 of the user interface part I was not operated for a predetermined time is mentioned, for example.

  When shifting to the sleep mode, the control unit 10 turns off the switches SW1 and SW2 (step S3). Thereby, the supply of the operation power supply voltage having the voltage value V1 and the operation power supply voltage having the voltage value V2 by the normal power supply unit 12 is stopped.

  And when the timing which should transfer to normal mode comes (YES of step S4), the control part 10 transfers to normal mode (step S5). In addition, as a timing which should transfer to normal mode, the time when the operation part 18 of the user interface part I is operated is mentioned, for example.

  When the control unit 10 shifts to the normal mode, the control unit 10 turns on the switches SW1 and SW2 (step S6). As a result, supply of the operation power supply voltage having the voltage value V1 and the operation power supply voltage having the voltage value V2 by the normal power supply unit 12 is started. Thereafter, the control unit 10 returns to Step S1.

A Image forming apparatus 1 Power supply apparatus 10 Control section 11 Sleep power supply section 12 Normal power supply section 16 Normal control section 17 Noise filter C9 Line capacitor R2 Discharge resistance SW1, SW2 switch L Power supply line 40 Image forming section 200 Image reading section

Claims (3)

A power supply device that supplies a power supply voltage for operation to a device having a sleep mode that suppresses power consumption and a normal mode that does not suppress power consumption,
A sleep power supply for supplying the operation power supply voltage to the device in the sleep mode;
A normal power supply for supplying the operating power supply voltage to the device in the normal mode;
A control unit,
The normal power supply unit is
A noise filter for removing noise of commercial AC power, the line capacitor connected to a power supply line to which the commercial AC power is input, the discharge resistor connected in parallel to the line capacitor, and the discharge A noise filter comprising a first switching unit connected between a resistor and the power line;
A power supply voltage generation unit that generates the operation power supply voltage based on the commercial AC power from which the noise has been removed by the noise filter,
The power supply voltage generator is
A diode bridge that rectifies the commercial AC power from which the noise has been removed by the noise filter;
A smoothing capacitor that smoothes commercial AC power rectified by the diode bridge and converts it into DC power;
A transformer for transforming the DC power to a predetermined voltage value;
A switching element that intermittently outputs the DC power to the first primary winding of the transformer;
A normal control unit for controlling a duty ratio of a pulse signal output to the switching element so that the operation power supply voltage becomes the predetermined voltage value;
A power supply circuit including a second primary winding of the transformer and a second switching unit connected in series to the second primary winding, and generating a voltage for operating the normal control unit,
The controller is
In the normal mode, the first switching unit is turned on, the second switching unit is turned on, and the operation power supply voltage is generated by the power supply voltage generation unit. In the sleep mode, the first switching unit is turned on . A power supply apparatus that turns off the switching unit and turns off the second switching unit to stop the generation of the operation power supply voltage by the power supply voltage generation unit. The power supply device according to claim 1, wherein the first switching unit is connected between a parallel circuit of the line capacitor and the discharge resistor and the power supply line. The power supply device according to claim 1 or 2,
An image reading unit for reading image data of a document;
An image forming unit for forming image data read by the image reading unit on a recording sheet;
An image forming apparatus comprising:

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