Image processing apparatus and heat generating resistor circuit

Abstract

The invention relates to an image processing apparatus and a heat generating resistor circuit. There is provided an image processing apparatus including: a first DC power source configured to output a first voltage; a second DC power source configured to output a second voltage, the second voltage being higher than the first voltage; a resistor circuit portion including at least one heat generating resistor, the at least one heat generating resistor configured to heat an interior of the image processing apparatus; and a control unit configured to switch a power supply that supplies power to the resistor circuit portion between the first DC power supply and the second DC power supply.

Description

Technical Field

[0001] The present invention relates to an image processing device and a heating resistor circuit. Background Art

[0002] The following technology is known: when an image processing device such as a printer or scanner is expected to be installed in a low-temperature environment, a heater is installed in the device to manage the temperature within the device in order to prevent printing and operational defects caused by phenomena (e.g., condensation) resulting from a drop in temperature. Since such a device needs to keep the heater active when not performing its main operation, it is generally connected to an AC commercial power source to supply power to the heater.

[0003] Japanese Patent Laid-Open No. 2007-57779 discloses a technology for an image forming apparatus having a heater and a fan for temperature control, which converts AC voltage from a commercial power supply into DC voltage and uses the DC voltage to operate equipment within the apparatus. By adopting a configuration in which DC voltage, rather than AC voltage, is supplied to the equipment for temperature control, as in the technology disclosed in Japanese Patent Laid-Open No. 2007-57779, it is possible to promote size reduction and efficient heating of the apparatus. Summary of the Invention

[0004] Generally, the load in the image processing device includes a control system load such as a processor (e.g., a CPU) and a drive system load such as a motor. By providing a second power supply for feeding the drive system load separately from the first power supply for feeding the control system load, it is possible to cut off the power feed from the second power supply during a period when the drive system is not operating in order to reduce power consumption. Since the operating voltage required for the control system is lower than the driving voltage of the drive system, the first power supply is generally configured to output a voltage lower than the voltage output from the second power supply. However, in a case where the first power supply is used to feed a heater that needs to be constantly kept active for the purpose of preventing dew condensation, when the entire device is highly loaded, there is a possibility that sufficient power is not supplied from the first power supply to the heater. At the same time, in a case where the second power supply is used to feed the heater, the power feed from the second power supply cannot be cut off for power saving.

[0005] In view of the foregoing, the present invention aims to provide a mechanism that enables an image processing apparatus to supply sufficient power to a heater in order to prevent defects due to a drop in temperature while satisfying the demand for power saving.

[0006] According to a first aspect, an image processing device is provided, comprising: a first DC power supply, configured to output a first voltage; a second DC power supply, configured to output a second voltage, the second voltage being higher than the first voltage; a resistor circuit portion, the resistor circuit portion comprising at least one heating resistor, the at least one heating resistor being configured to heat the interior of the image processing device; and a control unit, configured to switch a power source for supplying power to the resistor circuit portion between the first DC power supply and the second DC power supply.

[0007] According to a second aspect, a heating resistor circuit for use in an image processing device is provided, comprising: at least one heating resistor; and two or more connecting terminals, the two or more connecting terminals being configured to receive power supplied to the at least one heating resistor, wherein a first voltage and a second voltage are selectively applied to the two or more connecting terminals, the second voltage being higher than the first voltage.

[0008] According to a third aspect, an image processing device is provided, comprising: a heating resistor circuit according to the second aspect; and a control unit configured to selectively switch the voltage of the power supplied to the at least one heating resistor of the heating resistor circuit between the first voltage and the second voltage.

[0009] Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic configuration diagram illustrating an example of a configuration of a multifunction peripheral according to an embodiment;

[0011] Figure 2 is a circuit diagram illustrating a first embodiment example of a configuration of a circuit related to power supply control;

[0012] Figure 3A is an explanatory diagram illustrating how resistors are connected in parallel in the first power supply mode;

[0013] Figure 3B is an explanatory diagram illustrating how resistors are connected in series in the second power supply mode;

[0014] Figure 4 is a flowchart illustrating an example of the flow of a mode switching process according to the embodiment;

[0015] Figure 5 is a circuit diagram illustrating a second embodiment example of a configuration of a circuit related to power supply control;

[0016] Figure 6A is an explanatory diagram illustrating how resistors are connected in the first power supply mode;

[0017] Figure 6B is an explanatory diagram illustrating how resistors are connected in the second power supply mode; and

[0018] Figure 7 is a circuit diagram illustrating a modified example of the configuration of a circuit related to power supply control. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. While various features are described in the embodiments, this does not limit the invention to one requiring all such features, and multiple such features may be appropriately combined. Furthermore, in the accompanying drawings, identical or similar configurations are given identical reference numerals, and their repeated descriptions are omitted.

[0020] <1. Configuration Example of Multi-Function Peripheral Device>

[0021] Figure 1 1 is a schematic configuration diagram illustrating an example of a configuration of a multifunction peripheral 1 according to an embodiment. Figure 1 The multifunction peripheral 1 includes a printer unit 10, a scanner unit 50, an operation unit 70, and a controller 80. Each of the multifunction peripheral 1, the printer unit 10, and the scanner unit 50 is an example of an image processing apparatus.

[0022] The printer unit 10 is an image forming device that forms an image on a sheet. The printer unit 10 includes a paper feed cassette 15 , an image forming unit 20 , a conveying unit 30 , a fixing unit 40 , and a discharge tray 45 .

[0023] The image forming unit 20 includes a process unit 25, an intermediate transfer belt 107, a secondary transfer unit 108, and a belt cleaner 109. For simplicity of description, Figure 1 The image forming unit 20 is shown as including one process unit 25. However, the image forming unit 20 may include four process units 25 corresponding to the four color components of yellow, magenta, cyan, and black. That is, the printer unit 10 may be a monochrome printer or a color printer. The process unit 25 includes a photosensitive drum 101, a charging roller 102, a laser unit 103, a developing device 104, a primary transfer roller 105, and a drum cleaner 106.

[0024] The photosensitive drum 101 is an image carrier and rotates in the direction indicated by the arrow A1 in the figure. The charging roller 102 charges the surface of the photosensitive drum 101 to a uniform potential. The laser unit 103 has a semiconductor laser as a light source and forms an electrostatic latent image on the surface of the photosensitive drum 101 by exposing the photosensitive drum 101 to laser light according to the input image data. The developing device 104 develops the electrostatic latent image on the surface of the photosensitive drum 101 by supplying toner to it to form a toner image. The primary transfer roller 105 is applied with a transfer voltage as a high voltage and transfers the toner image on the surface of the photosensitive drum 101 to the intermediate transfer belt 107. The intermediate transfer belt 107 conveys the transferred toner image to the position of the secondary transfer unit 108.

[0025] The paper feed cassette 15 is a container unit that accommodates a stack of sheets. The transport unit 30 includes transport paths 111, 112, and 113, a feed roller 114, and a plurality of transport rollers. The feed roller 114 picks up sheets (also referred to as recording materials) P one by one from the stack of sheets accommodated in the paper feed cassette 15 to feed them to the transport path 111. When the sheet P transported along the transport path 111 reaches the secondary transfer position, the secondary transfer unit 108 transfers the toner image on the intermediate transfer belt 107 to the sheet P using the secondary transfer roller to which a transfer voltage, which is a high voltage, is applied. The transfer voltage can be optimized depending on the type of sheet P. The transport unit 30 may have a correction mechanism (not shown) that corrects the skew of the sheet P on the transport path 111.

[0026] The drum cleaner 106 removes the toner remaining on the surface of the photosensitive drum 101 . The belt cleaner 109 removes the toner remaining on the intermediate transfer belt 107 .

[0027] The fixing unit 40 has a fixing roller pair, and fixes the toner image to the sheet P by heating and pressing the sheet P to which the toner image has been transferred. The sheet P having passed through the fixing unit 40 is discharged to a discharge tray 45 .

[0028] When duplex printing is performed, the sheet P is returned to the transport path 112 and then reverses its direction of travel to enter the duplex transport path 113. This sheet P is returned to the transport path 111 with its front and back sides reversed, and a toner image is transferred to the back side by the secondary transfer unit 108. The fixing unit 40 fixes the toner image to the sheet P again by applying heat and pressure to the sheet P. The sheet P is then discharged to the discharge tray 45.

[0029] The scanner unit 50 is a reading device that optically reads a document. The scanner unit 50 includes an automatic document feeder (ADF) 151, a platen 152, and an optical unit 153. The ADF 151 feeds the sheets constituting the document one by one to a conveying path (not shown) within the scanner unit 50. Instead of being fed by the ADF 152, the sheets can be placed on the platen 152. The optical unit 153 includes an optical system consisting of a plurality of lenses and mirrors, an image sensor, and a signal processing circuit. The optical unit 153 is movable along the arrow A2 in the figure. When the ADF 151 is used, the optical unit 153 optically reads the sheet that is conveyed along the conveying path and passes through the reading position to generate read image data. When the sheet is placed on the platen 152, the optical unit 153 optically reads the sheet while moving along the arrow A2 to generate read image data.

[0030] The operation unit 70 provides a user interface for interaction between the multifunction peripheral 1 and the user. For example, the operation unit 70 may include input devices such as a touch panel, buttons, switches, and a microphone, and output devices such as a display and a speaker.

[0031] The controller 80 includes a memory and a processor, and controls the overall operation of the multifunction peripheral 1 described above by executing a computer program stored in the memory. For example, when a print job is instructed, the controller 80 controls the printer unit 10 to form an image on a sheet based on input image data received from an external device. When a scan job is instructed, the controller 80 controls the scanner unit 50 to read a sheet and store the read image data in a storage device (not shown) or transmit it to a specified destination. When a copy job is instructed, the controller 80 controls the scanner unit 50 to read a sheet and controls the printer unit 10 to form an image on another sheet based on the read image data.

[0032] In the present embodiment, the multifunction peripheral 1 further includes one or more resistor circuit portions for heating the interior of the device (hereinafter, also simply referred to as a heater). Figure 1The diagram illustrates an example in which the multifunction peripheral 1 includes three heaters 200a, 200b, and 200c. However, the multifunction peripheral 1 may include fewer or more heaters. The heater 200a is a first resistor circuit portion for heating the paper feed cassette 15. The heater 200a heats the paper feed cassette 15 together with the stack of sheets therein, thereby preventing conveying defects caused by moisture on the sheets. The heater 200b is a second resistor circuit portion for heating the image forming unit 20. The heater 200b heats the image forming unit 20, thereby preventing image formation defects caused by condensation of dew in the image forming unit 20 (e.g., the photosensitive drum 101). The heater 200c is a third resistor circuit portion for heating the optical unit 153. The heater 200c heats the optical unit 153, thereby preventing reading defects caused by condensation of dew in the optical unit 153.

[0033] Note that in the following description, when it is unnecessary to distinguish the heaters 200a, 200b, and 200c from one another, they are collectively referred to as heater 200 by omitting the last characters of the reference numerals. The controller 80 controls the supply of power to the heaters as follows.

[0034] <2. First embodiment example>

[0035] <2-1. Circuit Configuration Related to Power Supply Control>

[0036] Figure 2 1 is a circuit diagram illustrating a first embodiment example of a configuration of a circuit related to power supply control. In the first embodiment example, the multifunction peripheral 1 includes a first switch 211, a second switch 212, a third switch 213, a power plug 220, a first direct current (DC) power supply 221, a second DC power supply 222, a relay 223, a drive unit 225, and a control unit 240.

[0037] The resistor circuit portion 200 is a heating resistor circuit arranged in the multifunction peripheral 1. The resistor circuit portion 200 is connected to a circuit using Figure 1 At least one of the described heaters 200a, 200b, and 200c corresponds to the resistor circuit portion 200. The resistor circuit portion 200 includes at least one heat generating resistor for heating the inside of the printer unit 10 or the scanner unit 50, and two or more connection terminals. Figure 2The diagram shows an example in which the resistor circuit portion 200 includes a first resistor 201 and a second resistor 202 and four nodes N1 to N4. Nodes N1 to N4 receive power to be supplied to the first resistor 201 and the second resistor 202. One end of the first resistor 201 is connected to the node N1, and the other end is connected to the node N2. One end of the second resistor 202 is connected to the node N3, and the other end is connected to the node N4.

[0038] The first switch 211, the second switch 212, and the third switch 213 are switching circuits for switching the connection state of the power supply path between 'ON' and 'OFF'. For example, each switching circuit may be a mechanical relay or an electrical switching element (e.g., a field effect transistor (FET)). Each switching circuit may also include a diode to prevent reverse current flow.

[0039] The first switch 211 opens and closes the power supply path between the first DC power source 221 and the nodes N1 and N3. One end of the first switch 211 is connected to the nodes N1 and N3, and the other end of the first switch 211 is connected to the output terminal of the first DC power source 221. The control unit 240 can switch the state of the first switch 211 by outputting a switching signal Sig_A to the first switch 211.

[0040] The second switch 212 opens and closes the power supply path between the second DC power source 222 and the node N4. One end of the second switch 212 is connected to the node N4, and the other end is connected to the output terminal of the second DC power source 222. The control unit 240 can switch the state of the second switch 212 by outputting a switching signal Sig_B to the second switch 212.

[0041] The third switch 213 opens and closes the ground path between the node N4 and the ground. One end of the third switch 213 is connected to the power supply path between the second switch 212 and the node N4, and the other end is connected to the ground path between the node N2 and the ground. The control unit 240 can switch the state of the third switch 213 by outputting a switching signal Sig_C to the third switch 213.

[0042] The power plug 220 is connected to a commercial power source as an alternating current (AC) power source. Electric power from the commercial power source is supplied to a first DC power source 221 and is supplied to a second DC power source 222 via a relay 223.

[0043] The first DC power supply 221 acts as a DC power supply by converting the AC voltage of the commercial power supply into a DC voltage to output a first voltage VA. The first voltage VA is mainly used as an operating voltage of the control system. Figure 2In the example of , the first voltage VA is output to the first switch 211 and the control unit 240. The second DC power supply 222 acts as a DC power supply by converting the AC voltage of the commercial power supply into a DC voltage to output the second voltage VB. The second voltage VB is mainly used as a driving voltage of the driving system. Figure 2 In the example, the second voltage VB is output to the second switch 212 and the driving unit 225.

[0044] Generally, the driving voltage for the drive system is higher than the operating voltage of the control system. Therefore, the second DC power supply 222 generates a second voltage VB that is higher than the first voltage VA. However, if the second DC power supply 222 also generates the second voltage VB during periods when the multifunction peripheral 1 is not operating, wasteful power consumption would occur. Therefore, a relay 223 is provided at the power supply path from the power plug 220 to the second DC power supply 222. The relay 223 connects or disconnects the power supply path to the second DC power supply 222 based on a relay control signal Sig_R input from the control unit 240.

[0045] The driving unit 225 generates a driving unit for driving the combined Figure 1 The driving force of the various components described. The driving unit 225 may include, for example, a motor that generates a rotational driving force and a solenoid that displaces the components. A driving voltage based on the second voltage VB from the second DC power supply 222 is applied to the driving unit 225.

[0046] The control unit 240 is a control circuit that controls the supply of power to the various units of the multifunction peripheral 1. An operating voltage based on the first voltage VA from the first DC power supply 221 is applied to the control unit 240. The control unit 240 may be, for example Figure 1 . Typically, the control unit 240 includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a non-volatile memory, and an input / output (I / O) port. The ROM pre-stores one or more computer programs for power supply control. The RAM provides a temporary storage area for calculations by the CPU. The CPU implements the power supply control function of the control unit 240 by executing the computer program loaded in the RAM. The non-volatile memory stores data related to the power supply control even in a period when the control unit 240 is not supplied with power. The I / O port includes an input port for receiving a signal input to the control unit 240 and an output port for sending a signal output from the control unit 240. For example, the control unit 240 can cause the printer unit 10 to form an image by operating the motor and solenoid constituting the drive system at appropriate timing based on a sensor signal from a sensor (not shown) that detects the position of the conveyed sheet.

[0047] <2-2. Switching Power Supply Mode>

[0048] As described above, the resistor circuit section 200 is a heater used to prevent condensation in the multifunction peripheral 1 or to maintain the temperature at or near a target temperature. Therefore, regardless of whether the drive system is operating, power must be continuously supplied to the resistor circuit section 200. Furthermore, if a configuration is employed in which power is continuously supplied to the resistor circuit section 200 from the first DC power supply 221, which is not shut off for power conservation purposes, there is a possibility that the output from the first DC power supply 221 will become unstable while the drive system is operating, and that the output will not be able to supply sufficient power to the resistor circuit section 200.

[0049] Therefore, in this embodiment, the control unit 240 selectively switches the power source used to supply power to the resistor circuit section 200 between the first DC power source 221 and the second DC power source 222. In other words, the control unit 240 selectively switches the voltage of the power supplied to the at least one heating resistor of the resistor circuit section 200 between a first voltage VA from the first DC power source 221 and a second voltage VB from the second DC power source 222. That is, the first voltage VA and the second voltage VB are selectively applied to the connection terminals of the resistor circuit section 200. The control unit 240 can switch the power source used to supply power to the resistor circuit section 200 depending on the operating state of the multifunction peripheral 1. For example, in the first power supply mode, the control unit 240 causes power to be supplied from the first DC power source 221 to the resistor circuit section 200. The first power supply mode can be a mode for saving power consumed by the multifunction peripheral 1. Typically, the first power supply mode can be selected during periods when the drive system is not operating to save power consumed by the drive unit 225. In the following description, the first power supply mode is referred to as the power saving mode. In the power saving mode, the control unit 240 controls the relay 223 to stop supplying power from the commercial power source to the second DC power source 222 .

[0050] The control unit 240 causes power to be supplied from the second DC power supply 222 to the resistor circuit portion 200 in the second power supply mode. The second power supply mode is a mode for the multi-function peripheral 1 to perform image processing (for example, one or both of image formation and document reading). Typically, the second power supply mode can be selected to cause the drive unit 225 to operate. The operation of the drive unit 225 in the second power supply mode may include the above-mentioned image forming operation and reading operation and preparatory operations for those operations. In the following description, the second power supply mode during the preparatory operation is also referred to as the standby mode, and the second power supply mode during the actual image forming operation and reading operation is also referred to as the drive mode. In the standby mode and the drive mode, the control unit 240 controls the relay 223 so that power is supplied from the commercial power supply to the second DC power supply 222.

[0051] Therefore, the second DC power supply 222 generates the second voltage VB based on the AC voltage of the commercial power supply only in the standby mode and the driving mode in which power is supplied from the second DC power supply 222 to the resistor circuit portion 200. On the other hand, regardless of the power supply mode, that is, regardless of which of the first DC power supply 221 and the second DC power supply 222 supplies power to the resistor circuit portion 200, the operating voltage based on the first voltage VA from the first DC power supply 221 is applied to the control unit 240.

[0052] Generally, the amount of heat generated by a heating resistor having a constant resistance value increases as the voltage applied to the heating resistor becomes higher. In this embodiment example, in order to suppress the influence of the power supply mode to achieve stable heating of the heated member by the resistor circuit part 200, a mode in which the effective resistance value of the resistor circuit part 200 is within the first resistance value R A With a resistance value higher than the first resistance R A The second resistance value R B Then, in the power saving mode, in addition to setting the effective resistance value of the resistor circuit part 200 to the first resistance value R A In addition, the control unit 240 causes power to be supplied from the first DC power source 221 to the resistor circuit portion 200 at the first voltage VA. On the other hand, in addition to setting the effective resistance value of the resistor circuit portion 200 to the second resistance value R B In addition, the control unit 240 causes power to be supplied from the second DC power source 222 to the resistor circuit portion 200 at the second voltage VB.

[0053] Specifically, in the present embodiment example, switching of the effective resistance value of the resistor circuit portion 200 is performed by switching the connection of the first resistor 201 and the second resistor 202 between parallel connection and serial connection.

[0054] Figure 3A The diagram shows how the first resistor 201 and the second resistor 202 are connected in parallel in the first power supply mode (power saving mode). In the first power supply mode, the control unit 240 turns on the first switch 211 and the third switch 213, and turns off the second switch 212. This results in the first resistor 201 and the second resistor 202 of the resistor circuit part 200 being connected in parallel to the first DC power supply 221. Figure 3A , the parallel power supply paths are indicated by diagonal shading. The current from the first DC power supply 221 passes through the first switch 211 and branches toward nodes N1 and N3. The current that has passed through node N1 causes the first resistor 201 to heat up and flows to the ground via node N2. At the same time, the current that has passed through node N3 causes the second resistor 202 to heat up and flows to the ground via node N4 and the third switch 213. When the resistance value of the first resistor 201 is represented by R1 and the resistance value of the second resistor 202 is represented by R2, the effective resistance value R of the resistor circuit portion 200 with such a parallel connection is A It can be expressed as the following equation:

[0055] [Mathematical formula 1]

[0056]

[0057] Figure 3B The diagram shows how the first resistor 201 and the second resistor 202 are connected in series in the second power supply mode (standby mode and driving mode). In the second power supply mode, the control unit 240 turns off the first switch 211 and the third switch 213, and turns on the second switch 212. This causes the first resistor 201 and the second resistor 202 of the resistor circuit part 200 to be connected in series to the second DC power supply 222. Figure 3B In FIG, the series power supply path is indicated by diagonal shading. The current from the second DC power supply 222 passes through the second switch 212 and flows to the node N4. The current that has passed through the node N4 passes through the second resistor 202, the node N3, the node N1, and the first resistor 201 in sequence, causing both resistors to heat up, and flows to the ground via the node N2. The effective resistance value R of the resistor circuit portion 200 with such a series connection is B It can be expressed as the following equation:

[0058] [Mathematical formula 2]

[0059] R B =R1+R2 (2)

[0060] The resistance value R1 of the first resistor 201 and the resistance value R2 of the second resistor are selected in consideration of the first voltage VA and the second voltage VB. For example, the resistance values ​​R1 and R2 may be selected to satisfy the following equation:

[0061] [Mathematical formula 3]

[0062]

[0063] The left side of equation (3) represents the power consumption in the resistor circuit portion 200 in the first power supply mode, and the right side of equation (3) represents the power consumption in the resistor circuit portion 200 in the second power supply mode. Equation (3) can be converted using the resistance values ​​R1 and R2 as follows:

[0064] [Formula 4]

[0065]

[0066] By selecting the resistance values ​​R1 and R2 so as to satisfy equation (4), the member to be heated can be heated equally with consistent control logic in both power supply modes. That is, the control unit 240 does not need to switch the control logic of temperature control depending on the selected power supply mode.

[0067] As an example, assume that the first voltage VA is equal to 12 volts (V) and the second voltage is equal to 24 V. In this case, the resistance value R1 can be equal to the resistance value R2. When R2=R1 is substituted into the left side of equation (4) and VB=2*VA is substituted into the right side, the left side will be (R1+R1) 2 / R1 2 =4, and the right side will be (2*VA / VA) 2 =4, which means that equation (4) holds.

[0068] Table 1 below summarizes the power supply source, effective resistance value and mode description of the heater for the three types of modes mentioned above. The power consumption of the entire device in the power saving mode, standby mode and driving mode represented by W1, W2 and W3 respectively meets W1 <W2<W3。

[0069] [Table 1]

[0070]

[0071] Table 1. Sources of power supplied to heaters for each operation mode of the multifunction peripheral

[0072] <2-3. Processing Flow>

[0073] Figure 42 is a flowchart illustrating an example of the flow of a mode switching process that can be performed by the control unit 240. In the following description, a processing step will be abbreviated as S (step).

[0074] First, at S101, when the multifunction peripheral 1 is powered on, the control unit 240 executes a startup sequence to activate the first DC power supply 221 and the second DC power supply 222, and also powers on the various units of the multifunction peripheral 1 to check their conditions. In response to the execution of the startup sequence, the multifunction peripheral 1 transitions to the standby mode.

[0075] In the standby mode, at S102, the control unit 240 sets the effective resistance value of the resistor circuit part 200 to the second resistance value R B , and also causes power to be supplied from the second DC power supply 222 to the resistor circuit portion 200 at the second voltage VB. The resistor circuit portion 200 generates heat using the power supplied from the second DC power supply 222 and heats the member to be heated. Here, the power consumption at the resistor circuit portion 200 will be (VB) 2 / R B .

[0076] During the standby mode period, at S103 the control unit 240 waits for a job (eg, a print job, a copy job, or a scan job). In response to receiving the job, the process proceeds to S104 where the multifunction peripheral 1 transitions to the driving mode.

[0077] In the driving mode, at S104, the control unit 240 keeps the effective resistance value of the resistor circuit portion 200 set to the second resistance value R B , and still have power supplied from the second DC power source 222 to the resistor circuit portion 200 at the second voltage VB. The resistor circuit portion 200 generates heat using the power supplied from the second DC power source 222 and heats the member to be heated. Here, the power consumption at the resistor circuit portion 200 will be (VB) 2 / R B Furthermore, at S105, the control unit 240 executes the received job by controlling one or both of the printer unit 10 and the scanner unit 50. Then, the process returns to S102, and the multifunction peripheral 1 returns to the standby mode.

[0078] During the standby mode period, the control unit 240 periodically determines at step S106 whether to transition to the power saving mode. For example, the control unit 240 may determine to transition to the power saving mode when no job has been received for a predefined period of time or when the operation unit 70 has instructed to transition to the power saving mode. If it is determined that the standby mode is to be maintained, the process returns to step S102.

[0079] In the case where it is determined at S106 that the mode is to be changed to the power saving mode, the control unit 240 performs a sequence for mode change to the power saving mode at S107. For example, the control unit 240 turns on the first switch 211 and the third switch 213 and turns off the second switch, whereby the first resistor 201 and the second resistor 202 of the resistor circuit portion 200 are connected in parallel to the first DC power supply 221. This results in the effective resistance value of the resistor circuit portion 200 being set to the first resistance value R A The control unit 240 also stops the operation of the drive system and controls the relay 223 to cut off the power supply path from the commercial power source to the second DC power source 222 .

[0080] In the power saving mode, at S108, the control unit 240 causes power to be supplied from the first DC power source 221 to the resistor circuit portion 200 at the first voltage VA. The resistor circuit portion 200 generates heat using the power supplied from the first DC power source 221 and heats the member to be heated. Here, the power consumption at the resistor circuit portion 200 will be (VA) 2 / R A If the resistance values ​​R1 and R2 have been appropriately selected in consideration of the first voltage VA and the second voltage VB, then (VA) 2 / R A =(VB) 2 / R B holds, and the power consumption at the resistor circuit portion 200 remains constant regardless of the mode.

[0081] During the power saving mode period, at S109, the control unit 240 periodically determines whether to transition to the standby mode. For example, when a user operation is detected in the operation unit 70, the control unit 240 may determine to transition to the standby mode. If it is determined to remain in the power saving mode, the process returns to S108.

[0082] In the case where it is determined at S109 that the mode is to be transitioned to the standby mode, the control unit 240 performs a sequence of mode transition to the standby mode at S110. For example, the control unit 240 turns off the first switch 211 and the third switch 213 and turns on the second switch, whereby the first resistor 201 and the second resistor 202 of the resistor circuit part 200 are connected in series to the second DC power supply 222. This results in the effective resistance value of the resistor circuit part 200 being set to the second resistance value R B The control unit 240 also controls the relay 223 to resume the supply of electric power from the commercial power source to the second DC power source 222. The process then returns to S102.

[0083] This embodiment example describes a configuration in which the connection state of two heating resistors to the selected power supply source is switched between parallel and serial connection, depending on which of two DC power supplies outputting different voltages is selected as the power supply source. By switching the connection state as described above, the effective (combined) resistance value of the heating resistors changes, thereby maintaining a constant power consumption for heating the heated component. This avoids complicating the control logic for temperature control and ensures stable heating of the heater.

[0084] <3. Second embodiment example>

[0085] <3-1. Circuit Configuration Related to Power Supply Control>

[0086] Figure 5 1 is a circuit diagram illustrating a second embodiment example of a configuration of a circuit related to power supply control. In the second embodiment example, the multifunction peripheral 1 includes a resistor circuit portion 200, a fourth switch 214, a fifth switch 215, a sixth switch 216, a power plug 220, a first DC power supply 221, a second DC power supply 222, a relay 223, a drive unit 225, a first diode 231, a second diode 232, and a control unit 250.

[0087] The resistor circuit portion 200 is a heating resistor circuit arranged in the multifunction peripheral 1. Also in this embodiment example, the resistor circuit portion 200 is connected to the multifunction peripheral 1 using a Figure 1 At least one of the described heaters 200a, 200b, and 200c corresponds to the resistor circuit portion 200. The resistor circuit portion 200 includes at least one heat generating resistor for heating the inside of the printer unit 10 or the scanner unit 50, and two or more connection terminals. Figure 5The diagram shows an example in which the resistor circuit portion 200 includes a third resistor 203 and a fourth resistor 204 and three nodes N5 to N7. Nodes N5 to N7 receive power to be supplied to the third resistor 203 and the fourth resistor 204. One end of the third resistor 203 is connected to the node N5, and the other end is connected to the node N6. One end of the fourth resistor 204 is connected to the node N5, and the other end is connected to the node N7. The resistance value of the third resistor 203 is equal to the first resistance value R described in conjunction with the first embodiment. A The resistance value of the fourth resistor 204 is equal to the second resistance value R described in conjunction with the first embodiment. B .

[0088] The fourth switch 214 , the fifth switch 215 , and the sixth switch 216 are switching circuits for switching the connection state of the power supply path between “ON” and “OFF.” For example, each switching circuit may be a mechanical relay or an electrical switching element.

[0089] The fourth switch 214 opens and closes the power supply path through the third resistor 203. One end of the fourth switch 214 is connected to the node N6, and the other end is connected to the ground. The control unit 250 can switch the state of the fourth switch 214 by outputting a switching signal Sig_D to the fourth switch 214.

[0090] The fifth switch 215 opens and closes the power supply path through the fourth resistor 204. One end of the fifth switch 215 is connected to the node N7, and the other end is connected to the ground. The control unit 250 can switch the state of the fifth switch 215 by outputting a switching signal Sig_E to the fifth switch 215.

[0091] The sixth switch 216 opens and closes the power supply path from the first DC power source 221. One end of the sixth switch 216 is connected to the node N5, and the other end is connected to the first diode 231. The control unit 250 can switch the state of the sixth switch 216 by outputting a switching signal Sig_F to the sixth switch 216.

[0092] Also in this embodiment example, the first voltage VA of the direct current output from the first DC power supply 221 is mainly used as an operating voltage of the control system. Figure 5 In the example of FIG, the first voltage VA is output to the first diode 231 and the control unit 250. The second voltage VB of the direct current output from the second DC power supply 222 is mainly used as a driving voltage of the driving system. Figure 5In the example, the second voltage VB is output to the second diode 232 and the driving unit 225. The relay 223 connects or disconnects the power supply path from the commercial power source to the second DC power source 222 according to the relay control signal Sig_R input from the control unit 250.

[0093] The first diode 231 prevents reverse current from flowing in the power supply path of the first DC power supply 221. The input of the first diode 231 is connected to the first DC power supply 221. The output of the first diode 231 is connected to the other end of the sixth switch 216 mentioned above. The second diode 232 prevents reverse current from flowing in the power supply path of the second DC power supply 222. The input of the second diode 232 is connected to the second DC power supply 222. The output of the second diode 232 is connected to one end of the sixth switch 216 and the node N5.

[0094] The control unit 250 is a control circuit that controls the supply of power to the various units of the multifunction peripheral 1. An operating voltage based on the first voltage VA from the first DC power supply 221 is applied to the control unit 250. Similar to the control unit 240 according to the first embodiment, the control unit 250 includes a CPU, ROM, RAM, nonvolatile memory, and an I / O port. For example, the control unit 250 can cause the printer unit 10 to form an image by operating the motor and solenoid constituting the drive system at appropriate timings based on sensor signals from a sensor (not shown) that detects the position of a conveyed sheet.

[0095] <3-2. Switching Power Supply Mode>

[0096] Also in this embodiment example, the control unit 250 selectively switches the power supply for supplying electric power to the resistor circuit portion 200 between the first DC power supply 221 and the second DC power supply 222. For example, the control unit 250 causes electric power to be supplied from the first DC power supply 221 to the resistor circuit portion 200 in the first power supply mode (power saving mode). In the power saving mode, the control unit 250 controls the relay 223 to stop the supply of electric power from the commercial power supply to the second DC power supply 222.

[0097] The control unit 250 supplies power from the second DC power supply 222 to the resistor circuit portion 200 in the second power supply mode (standby mode and drive mode). In the standby mode and drive mode, the control unit 250 controls the relay 223 so that power is supplied from the commercial power supply to the second DC power supply 222.

[0098] Furthermore, in the power saving mode, in addition to setting the effective resistance value of the resistor circuit portion 200 to the first resistance value R AIn addition, the control unit 250 causes power to be supplied from the first DC power supply 221 to the resistor circuit portion 200 at the first voltage VA. On the other hand, in the standby mode and the driving mode, in addition to setting the effective resistance value of the resistor circuit portion 200 to the second resistance value R B In addition, the control unit 250 causes power to be supplied from the second DC power source 222 to the resistor circuit portion 200 at the second voltage VB.

[0099] Specifically, in the present embodiment example, switching of the effective resistance value of the resistor circuit portion 200 is performed by opening one of the power supply path through the third resistor 203 and the power supply path through the fourth resistor 204 and closing the other.

[0100] Figure 6A The diagram shows how the third resistor 203 and the fourth resistor 204 are connected in the first power supply mode (power saving mode). In the first power supply mode, the control unit 250 turns on the fourth switch 214 and the sixth switch 216, and turns off the fifth switch 215. This causes the power supply path between the first DC power supply 221 and the ground through the third resistor 203 to be closed. In other words, current is transferred from the first DC power supply 221 to the ground via the third resistor 203. On the other hand, the power supply path through the fourth resistor 204 is opened. In other words, the current through the fourth resistor 204 is cut off. In Figure 6A , the power supply path through the third resistor 203 is indicated by diagonal hatching. The current from the first DC power supply 221 passes through the first diode 231, the sixth switch 216, the node N5, the third resistor 203, the node N6 and the fourth switch 214, and flows to the ground. In this case, the effective resistance value of the resistor circuit portion 200 is equal to the resistance value R of the third resistor 203. A .

[0101] Figure 6B The diagram shows how the third resistor 203 and the fourth resistor 204 are connected in the second power supply mode (standby mode and driving mode). In the second power supply mode, the control unit 250 turns off the fourth switch 214 and the sixth switch 216, and turns on the fifth switch 215. This results in the power supply path through the third resistor 203 being opened, while the power supply path between the second DC power supply 222 and the ground through the fourth resistor 204 is closed. Figure 6B , the power supply path through the fourth resistor 204 is indicated by diagonal hatching. The current from the second DC power supply 222 passes through the second diode 232, the node N5, the fourth resistor 204, the node N7 and the fifth switch 215, and flows to the ground. In this case, the effective resistance value of the resistor circuit portion 200 is equal to the resistance value R of the fourth resistor 204.B .

[0102] The resistance value R of the third resistor 203 may be selected in consideration of the first voltage VA and the second voltage VB. A and the resistance value of the fourth resistor R B , so that the above equation (3) is satisfied. In this way, the component to be heated can be heated equally with consistent control logic in both power supply modes. That is, the control unit 250 does not need to switch the control logic of the temperature control depending on the selected power supply mode.

[0103] As an example, assume that the first voltage VA is equal to 12 V and the second voltage is equal to 24 V. In this case, the resistance value R B It can be the resistance value R A When R is substituted into the right side of equation (3) B =4*R A When VB=2*VA, the right side will be (2*VA) 2 / 4*R A =VA 2 / R A , which is equal to the left side, which means that equation (3) holds.

[0104] <3-3. Processing Flow>

[0105] The process of the mode switching process that can be performed by the control unit 250 in this embodiment example can be similar to that of using Figure 4 However, according to this embodiment example, when transitioning to the power saving mode at S107, the control unit 250 sets the effective resistance value of the resistor circuit portion 200 to the first resistance value R by closing the power supply path from the first DC power supply 221 through the third resistor 203. A The operation of the drive system is stopped, and the power supply path from the commercial power supply to the second DC power supply 222 is cut off. In addition, when transitioning to the standby mode at S110, the control unit 240 sets the effective resistance value of the resistor circuit portion 200 to the second resistance value R by closing the power supply path from the second DC power supply 222 through the fourth resistor 204. B The operation of the drive system is enabled, and electric power is supplied to the second DC power supply 222 from the commercial power supply.

[0106] This embodiment describes a configuration in which the heating resistor's connection to the selected power supply source is switched between two heating resistors depending on which of two DC power supplies outputting different voltages is selected as the power supply source. By switching the connection state as described above, the power consumed to heat the heated component remains constant. This avoids complicating the temperature control logic and ensures stable heating by the heater.

[0107] <4. Modification Example>

[0108] Various modification examples can be conceived of the above-described embodiment examples.

[0109] For example, the first and second embodiment examples have been described using an example in which the power supply mode of the resistor circuit portion 200 is switched in coordination with the operating mode of the multifunction peripheral 1. However, the triggering of switching the power supply mode is not limited to such an example. In a first modified example, the switching of the power supply mode may be triggered based on a comparison between the amount of consumed current detected for a selected power supply source and a predefined threshold value, rather than being triggered in coordination with the operating mode of the multifunction peripheral 1. In this modified example, in a state in which power is supplied to the resistor circuit portion 200 from the first DC power supply 221, when the amount of current consumed in the first DC power supply 221 exceeds a first threshold value, the power supply source is switched from the first DC power supply 221 to the second DC power supply 222. Furthermore, in a state in which power is supplied to the resistor circuit portion 200 from the second DC power supply 222, when the amount of current consumed in the second DC power supply 222 decreases to below a second threshold value, the power supply source is switched from the second DC power supply 222 to the first DC power supply 221. Also in this modified example, the effective resistance value of the resistor circuit portion 200 can be set to one of two different values ​​depending on the selected power supply source (by switching between parallel connection and serial connection or by exclusive connection of either of the two heating resistors).

[0110] In the second modified example, the multifunction peripheral 1 may further include a temperature control function for enabling finer temperature control and an abnormality detection function for detecting an abnormality in the power supply path. Figure 7 An example of the configuration of a circuit according to a second modification example is illustrated. Figure 7 In the example, except Figure 2 The multifunction peripheral 1 includes a temperature sensor 291 and a detection circuit 292 in addition to the constituent elements according to the first embodiment example shown in FIG.

[0111] The temperature sensor 291 is a measuring unit configured to measure the temperature of a heated component. When the resistor circuit portion 200 corresponds to the heater 200a, the heated component may be the paper feed cassette 15 (or the sheet stack therein). When the resistor circuit portion 200 corresponds to the heater 200b, the heated component may be the image forming unit 20. When the resistor circuit portion 200 corresponds to the heater 200c, the heated component may be the optical unit 153. The temperature sensor 291 outputs a sensor signal Sig_T indicating the temperature of the heated component to the control unit 290.

[0112] Detection circuit 292 is a detection unit configured to detect the magnitude of the current flowing in resistor circuit portion 200. One end of detection circuit 292 is connected to node N2 and third switch 213, and the other end of detection circuit 292 is connected to ground. In the first power supply mode, detection circuit 292 detects the magnitude of the current that has been output from first DC power supply 221 and has passed through first resistor 201 and second resistor 202 in parallel. In the second power supply mode, detection circuit 292 detects the magnitude of the current that has been output from second DC power supply 222 and has passed through first resistor 201 and second resistor 202 in sequence. Detection circuit 292 outputs a detection signal Sig_I indicating the magnitude of the detected current to control unit 290.

[0113] Control unit 290 controls the supply of power to resistor circuit portion 200 based on the measured temperature of the heated component, as indicated by sensor signal Sig_T from temperature sensor 291, so that the temperature of the heated component is maintained at a target temperature. For example, control unit 290 can maintain the temperature of the heated component at or near the target temperature by opening and closing a switching element in the power supply path at a duty cycle determined by well-known feedback control. In this way, temperature control in multifunction peripheral 1 can be refined, and defects caused by temperature drops can be more effectively prevented.

[0114] Furthermore, the control unit 290 detects an abnormality in the power supply path in the multifunction peripheral 1 based on the selected power supply mode and the magnitude of the current (detected current value) indicated by the detection signal Sig_I from the detection circuit 292. The selected power supply mode can indicate which of the first DC power supply 221 and the second DC power supply 222 is being caused to supply power to the resistor circuit portion 200 at that point in time. Table 2 below indicates some examples of abnormality detection conditions based on the power supply mode and the detected current value.

[0115] [Table 2]

[0116]

[0117]

[0118] Table 2. Examples of abnormality detection conditions based on power supply mode and detected current value

[0119] According to the first entry of Table 2, when the current value detected in the first power supply mode is greater than a predetermined upper limit value, the control unit 290 can detect an abnormality caused by the deterioration of the heating resistor of the resistor circuit part 200. According to the second entry, when the current value detected in the first power supply mode is less than a predetermined lower limit value, the control unit 290 can detect an abnormality caused by the disconnection of the power supply path. According to the third entry, when the current value detected in the second power supply mode is greater than a predetermined upper limit value, the control unit 290 can detect an abnormality caused by the failure of any switch. The abnormality detection condition of the fourth entry is similar to the abnormality detection condition of the second entry, and when the current value detected in the second power supply mode is less than a predetermined lower limit value, the control unit 290 can detect an abnormality caused by the disconnection of the power supply path. However, the lower limit value to be compared with the current value may be different between the first power supply mode and the second power supply mode.

[0120] When the control unit 290 has detected an abnormality according to the abnormality detection conditions exemplified above, it may notify the user of the occurrence of the abnormality and the estimated cause of the abnormality via the operation unit 70 so as to promptly prompt the user to check the cause and take appropriate repair measures.

[0121] In another modified example, the multifunction peripheral 1 may include a constant current circuit in one or both of the power supply path from the first DC power supply 221 and the power supply path from the second DC power supply 222. The constant current circuit adjusts the amount of current so that it does not exceed the rated current. This allows further optimization of the power consumed to heat the heated member.

[0122] Although the first embodiment example and the second embodiment example have been described using an example in which the multifunction peripheral device 1 includes two DC power supplies, the technology according to the present disclosure is not limited to this example. In a modified example, the technology according to the present disclosure can be applied to an image processing device including a single power supply circuit (variable output power supply) capable of outputting a variable voltage. In this modified example, the power supply circuit is configured to supply power to the load of the control system (e.g., a processor) and the load of the drive system (e.g., a motor) of the image processing device. For example, the power supply circuit supplies power to the control system and the heater at a first voltage in a power saving mode (a first power supply mode). At this time, the supply of power to the drive system is cut off. On the other hand, the power supply circuit supplies power to the control system, the heater, and the drive system at a second voltage higher than the first voltage in a standby mode and a drive mode (a second power supply mode). In this way, even in a case where the image processing device includes only a single power supply circuit, it is possible to supply sufficient power to the heater while meeting the power saving requirements by selectively applying different voltages to the heater.

[0123] 5. Conclusion

[0124] So far, references have been Figures 1 to 7 Embodiments of the technology according to the present disclosure and various related embodiment examples and modification examples are described. In the above-mentioned embodiment, the image processing device includes a first DC power supply configured to output a first voltage, a second DC power supply configured to output a second voltage higher than the first voltage, and a resistor circuit portion including at least one heating resistor for heating the interior of the image processing device. The control unit of the image processing device is configured to selectively switch the power supply for supplying power to the resistor circuit portion between the first DC power supply and the second DC power supply. According to this configuration, in a situation where sufficient power capacity may be required, the second DC power supply can be activated to supply power from the second DC power supply to the heating resistor. In addition, in a situation where power saving may be required, the heated component can be heated by supplying power from the first DC power supply to the heating resistor while cutting off the supply of power from the second DC power supply to reduce power consumption. Thus, it is possible to prevent defects caused by a drop in temperature while meeting the requirements for power saving.

[0125] The above-described embodiment examples and modification examples can be combined with each other in any manner. Figure 7 One or more of the temperature control function, abnormality detection function, and constant current circuit described above can be combined with any one of the first embodiment example and the second embodiment example. Figure 1 It is described that some of the plurality of heaters are supplied with electric power while the other heaters are supplied with electric power as in the second embodiment example.

[0126] <6. Other embodiments>

[0127] The embodiments of the present invention can also be implemented by reading and executing computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which can also be more fully referred to as a 'non-transitory computer-readable storage medium') to perform one or more functions of the above-described embodiments and / or a computer of a system or device including one or more circuits (e.g., an application-specific integrated circuit (ASIC)) for performing one or more functions of the above-described embodiments, and by a method performed by a computer of the system or device by, for example, reading and executing computer-executable instructions from a storage medium to perform one or more functions of the above-described embodiments and / or controlling one or more circuits to perform one or more functions of the above-described embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of separate computers or separate processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)). TM ), one or more of a flash memory device, a memory card, etc.

[0128] The embodiments of the present invention can also be implemented by the following method, that is, software (including computer program products of computer programs / instructions) that perform the functions of the above-mentioned embodiments is provided to a system or device through a network or various storage media, and a computer (central processing unit (CPU), microprocessing unit (MPU)) of the system or device reads and executes the computer program / instructions.

[0129] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image processing device, comprising: a first DC power supply configured to output a first voltage; a second DC power supply, the second DC power supply being configured to output a second voltage, the second voltage being higher than the first voltage; a resistor circuit portion including at least one heat generating resistor configured to heat an interior of the image processing apparatus; as well as A control unit configured to switch a power source that supplies power to the resistor circuit portion between the first DC power source and the second DC power source.

2. The image processing apparatus according to claim 1, wherein The resistor circuit portion is configured to change an effective resistance value of the resistor circuit portion between a first resistance value and a second resistance value, the second resistance value being higher than the first resistance value, and The control unit is configured to: setting the effective resistance value of the resistor circuit portion to the first resistance value when the first DC power supply supplies power to the resistor circuit portion, and When the second DC power supply supplies power to the resistor circuit portion, the effective resistance value of the resistor circuit portion is set to the second resistance value.

3. The image processing apparatus according to claim 2, wherein The at least one heating resistor of the resistor circuit portion includes a first resistor and a second resistor, and The control unit is configured to: setting an effective resistance value of the resistor circuit portion to the first resistance value by connecting the first resistor and the second resistor in parallel to the first DC power supply when the first DC power supply supplies power to the resistor circuit portion, and When the second DC power supply supplies power to the resistor circuit portion, the effective resistance value of the resistor circuit portion is set to the second resistance value by connecting the first resistor and the second resistor in series to the second DC power supply.

4. The image processing apparatus according to claim 3, further comprising: A first switch, a second switch, and a third switch, each switch having a first terminal and a second terminal, wherein each of the first resistor and the second resistor has a first end and a second end, A first end of the first resistor and a first end of the second resistor are connected to a first end of the first switch, The second end of the first switch is connected to the first DC power supply, The second end of the second resistor is connected to the first end of the second switch, The second end of the second switch is connected to the second DC power supply, The second end of the first resistor is connected to the first end of the third switch and ground, The second end of the third switch is connected to the first end of the second switch, and The control unit is configured to: connecting the first resistor and the second resistor of the resistor circuit portion to the first DC power supply in parallel by turning on the first switch and the third switch and turning off the second switch, and The first resistor and the second resistor of the resistor circuit portion are connected in series to the second DC power supply by turning off the first switch and the third switch and turning on the second switch.

5. The image processing apparatus according to claim 2 , wherein the at least one heat generating resistor includes a third resistor and a fourth resistor, the third resistor having the first resistance value, the fourth resistor having the second resistance value, and The control unit is configured to: When the first DC power supply supplies power to the resistor circuit portion, the effective resistance value of the resistor circuit portion is set to the first resistance value by closing the power supply path from the first DC power supply through the third resistor, and When the second DC power supply supplies power to the resistor circuit portion, the effective resistance value of the resistor circuit portion is set to the second resistance value by closing a power supply path from the second DC power supply through the fourth resistor. The image processing apparatus according to claim 1 , wherein The at least one heating resistor of the resistor circuit portion includes a first resistor and a second resistor, and The control unit is configured to: connecting the first resistor and the second resistor in parallel to the first DC power supply when the first DC power supply supplies power to the resistor circuit portion, and The first resistor and the second resistor are connected in series to the second DC power supply when the second DC power supply supplies power to the resistor circuit portion.

7. The image processing apparatus according to claim 1, wherein The at least one heating resistor includes a third resistor and a fourth resistor, the third resistor having a first resistance value, the fourth resistor having a second resistance value higher than the first resistance value, and The control unit is configured to: When the first DC power supply supplies power to the resistor circuit portion, closing a power supply path from the first DC power supply through the third resistor, and When the second DC power supply supplies power to the resistor circuit portion, a power supply path from the second DC power supply through the fourth resistor is closed. The image processing apparatus according to claim 1 , wherein The first DC power supply is configured to convert an AC voltage of a commercial power supply into the first DC voltage to output the first voltage, and The second DC power supply is configured to convert the AC voltage of the commercial power supply into the second DC voltage to output the second voltage.

9. The image processing apparatus according to claim 1, further comprising: Drive unit, wherein an operating voltage based on the first voltage output from the first DC power supply is applied to the control unit, and A driving voltage based on the second voltage output from the second DC power supply is applied to the driving unit. 10 . The image processing apparatus according to claim 9 , wherein the operating voltage is applied to the control unit regardless of which of the first DC power source and the second DC power source supplies power to the resistor circuit portion. 11 . The image processing apparatus according to claim 10 , wherein the second DC power supply is configured to generate the second voltage only when power is supplied from the second DC power supply to the resistor circuit portion.

12. The image processing apparatus according to claim 9, wherein The control unit is configured to switch between the first DC power supply and the second DC power supply so that: In a first power supply mode for saving power consumed in the drive unit, the first DC power supply supplies power to the resistor circuit portion, and The second DC power supply supplies power to the resistor circuit portion in a second power supply mode for operating the drive unit.

13. The image processing apparatus according to claim 1, wherein the control unit is configured to switch a power source that supplies power to the resistor circuit portion between the first DC power source and the second DC power source depending on an operation state of the image processing apparatus.

14. The image processing apparatus according to claim 1, wherein The control unit is configured to switch between the first DC power supply and the second DC power supply so that: In a first power supply mode for saving consumed power, the first DC power supply supplies power to the resistor circuit portion, and The second DC power supply supplies power to the resistor circuit portion in a second power supply mode in which the image processing apparatus performs image processing.

15. The image processing apparatus according to claim 1, wherein the image processing apparatus comprises an image forming apparatus configured to form an image on a sheet, and The resistor circuit portion includes at least one of: a first resistor circuit portion for heating a container unit configured to accommodate a stack of sheets; and a second resistor circuit portion for heating an image forming unit.

16. The image processing apparatus according to claim 1, wherein the image processing apparatus comprises a reading device configured to optically read a document, and The resistor circuit portion includes a third resistor circuit portion for heating an optical system of the reading device.

17. The image processing apparatus according to claim 1, further comprising a measuring unit configured to measure a temperature of a heated member configured to be heated by the at least one heat generating resistor, and The control unit is configured to control power supplied to the resistor circuit portion based on the temperature measured by the measuring unit.

18. The image processing apparatus according to claim 1 , further comprising a detection unit configured to detect a magnitude of a current flowing in the resistor circuit portion, and The control unit is configured to detect an abnormality in a power supply path in the image processing apparatus based on which of the first and second DC power supplies is caused to supply power to the resistor circuit portion and the magnitude of the current detected by the detection unit.

19. A heating resistor circuit for use in an image processing device, comprising: at least one heating resistor; as well as two or more connection terminals configured to receive power supplied to the at least one heating resistor, A first voltage and a second voltage are selectively applied to the two or more connection terminals, the second voltage being higher than the first voltage.

20. An image processing device, comprising: The heating resistor circuit according to claim 19; as well as A control unit configured to selectively switch a voltage of power supplied to the at least one heating resistor of the heating resistor circuit between the first voltage and the second voltage.

Images