Power supply device and image processing device

Abstract

To provide a power supply device and an image processing device capable of easily simplifying a configuration and control.SOLUTION: A power supply device 3 includes a signal generation unit 31, a voltage generation unit 32 and a correction unit 33. The signal generation unit 31 generates a PWM signal Si2. The voltage generation unit 32 adjusts an output voltage value according to the PWM signal Si2. The correction unit 33 obtains a correction value of a duty ratio according to a frequency or a cycle of the PWM signals Si2, and corrects the duty ratio of the PWM signal Si2 based on the correction value.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a power supply device and an image processing device. [Background technology]

[0002] As a related art, there is known an image processing device (image forming device) that incorporates components such as a developing roller that require a high voltage, and that is configured such that a high voltage output circuit of a power supply device (high voltage board) applies a predetermined high voltage to such components (see, for example, Patent Document 1). In the power supply device of the related art, a voltage generating unit (high voltage output circuit) generates a high voltage that corresponds to the duty ratio of a PWM signal (rectangular signal) input from a signal generating unit (control board).

[0003] In the above related technology, the signal generating unit includes a controller that outputs a rectangular control signal, and a driver circuit that generates a PWM signal in response to a level change of the rectangular control signal and outputs the PWM signal to the voltage generating unit. The controller measures the duty of the PWM signal, identifies the difference between the duty of the rectangular control signal and the duty of the PWM signal, and corrects the duty of the rectangular control signal based on the identified difference. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-32730 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the power supply device according to the above related art requires a circuit for measuring the duty cycle of the PWM signal, making it difficult to simplify the configuration and control of the power supply device.

[0006] An object of the present invention is to provide a power supply device and an image processing device that can easily be simplified in configuration and control. [Means for solving the problem]

[0007] A power supply device according to one aspect of the present invention includes a signal generating unit, a voltage generating unit, and a correction unit. The signal generating unit generates a PWM signal. The voltage generating unit adjusts an output voltage value in response to the PWM signal. The correction unit obtains a correction value for a duty ratio in response to a frequency or period of the PWM signal, and corrects the duty ratio of the PWM signal based on the correction value.

[0008] An image processing device according to another aspect of the present invention includes the power supply device described above and a main body having an image processing function. Effect of the Invention

[0009] According to the present invention, it is possible to provide a power supply device and an image processing device that can easily simplify the configuration and control. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic block diagram of an image processing device according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the appearance of the image processing device according to the first embodiment. [Diagram 3] FIG. 3 is an explanatory diagram showing the relationship between the output voltage value and the duty ratio of the PWM signal in the power supply device of the image processing apparatus according to the first embodiment. [Figure 4] FIG. 4 is a schematic circuit diagram illustrating an example of a power supply device of the image processing apparatus according to the first embodiment. [Diagram 5] FIG. 5 is an explanatory diagram showing the relationship between the drive signal and the PWM signal in the power supply device of the image processing device according to the first embodiment. [Figure 6] FIG. 6 is a schematic circuit diagram illustrating an example of a power supply device of the image processing device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0012] (Embodiment 1) [1] Overall configuration of image processing device First, the overall configuration of an image processing device 10 according to this embodiment will be described with reference to FIGS.

[0013] The image processing device 10 according to the present embodiment is, for example, a multifunction device having multiple functions such as a scanning function for acquiring image data from an original, a printing function for forming an image based on image data, a facsimile function, and a copy function. The image processing device 10 only needs to have an image processing function including at least one of a function for forming an image and a function for acquiring image data, and may be a printer, a scanner, a facsimile machine, a copy machine, or the like.

[0014] As shown in Fig. 1, the image processing device 10 includes an automatic document feeder 11, an image reading unit 12, an image forming unit 13, a developing unit 17, a paper feed unit 14, an operation display unit 15, a main body control unit 16, and a power supply unit 3. The automatic document feeder 11 is an ADF (Auto Document Feeder), and is therefore written as "ADF" in Fig. 1 and will also be referred to as "ADF 11" in the following description. In this embodiment, as shown in Fig. 2, the image processing device 10 includes a housing 101. The ADF 11, the image reading unit 12, the image forming unit 13, the developing unit 17, the paper feed unit 14, the operation display unit 15, the main body control unit 16, and the power supply unit 3 are provided in the housing 101.

[0015] The image processing device 10 includes a main body 1 having an image processing function. The main body 1 includes an ADF 11, an image reading unit 12, an image forming unit 13, a developing device 17, a paper feed unit 14, an operation display unit 15, and a main body control unit 16. In other words, the image processing device 10 includes the main body 1 having an image processing function and a power supply unit 3.

[0016] The ADF 11 transports an original document whose image is to be read by the image reading unit 12. The ADF 11 includes an original document setting unit, a plurality of transport rollers, an original document pressing unit, and a paper ejection unit.

[0017] The image reading unit 12 reads an image from a document and outputs image data corresponding to the read image. The image reading unit 12 includes a document table, a light source, a plurality of mirrors, an optical lens, a CCD (Charge Coupled Device), and the like.

[0018] The image forming unit 13 forms an image on a sheet by electrophotography based on image data output from the image reading unit 12. The image forming unit 13 also forms an image on a sheet based on image data input from an information processing device external to the image processing device 10, such as a personal computer.

[0019] The image forming section 13 has four image forming units corresponding to the four colors of C (cyan), M (magenta), Y (yellow) and K (black), an optical scanning device, an intermediate transfer belt, a secondary transfer roller, a fixing device, etc. Each image forming unit has a photosensitive drum, a charging roller, a primary transfer roller, a drum cleaning unit, etc. The image forming section 13 may be configured to form an image on a sheet by an image forming method other than the electrophotographic method, such as an inkjet method.

[0020] The image forming unit 13 forms an image on a sheet using toner as a developer. When the image forming unit 13 forms an image by an inkjet method, ink (another example of a developer) is supplied instead of toner. Examples of toner supplied to the image forming unit 13 include toner of multiple colors, such as C (cyan), M (magenta), Y (yellow), and K (black). After the image is formed in the image forming unit 13, the sheet is discharged (supplied) to an extension device or the like for post-processing.

[0021] The developing device 17 executes a developing process to develop the electrostatic latent image formed on the surface of the photoconductor drum of the image forming section 13. In particular, in this embodiment, the developing device 17 performs development using a two-component developer containing toner and carrier. The developing device 17 has four developing units corresponding to the four image forming units. Each developing unit has a developing roller, a magnet roller, and the like.

[0022] The paper feed unit 14 supplies a sheet to the image forming unit 13. The paper feed unit 14 has a paper feed cassette, a manual feed tray, a sheet transport path, a plurality of transport rollers, etc. The image forming unit 13 forms an image on the sheet supplied from the paper feed unit 14. The sheet supplied to the image forming unit 13 is paper as an example, but is not limited to paper and may be, for example, a resin film, etc.

[0023] The operation display unit 15 is a user interface in the image processing device 10. The operation display unit 15 has a display unit such as a liquid crystal display that displays various information in response to control instructions from the control unit of the main body, and an operation unit such as a switch or a touch panel that inputs various information to the control unit of the main body in response to user operations. Furthermore, the image processing device 10 may be provided with, for example, a voice output unit and a voice input unit, in addition to or instead of the operation display unit 15, as a user interface.

[0024] The main body control unit 16 mainly comprises a computer system having one or more processors and one or more memories, and performs overall control of the image processing device 10. In the image processing device 10, the one or more processors execute programs to realize the functions of the main body control unit 16. In this embodiment, as an example, the main body control unit 16 includes a CPU (Central Processing Unit).

[0025] The power supply device 3 applies a relatively high voltage (high voltage) independently to high voltage driving parts, such as the developing roller of the developing device 17 and the charging roller and transfer roller of the image forming unit 13. In other words, the power supply device 3 is a device that outputs power for the operation of the high voltage driving parts of the image processing device 10. In this embodiment, the power supply device 3 includes a signal generating unit 31 and a voltage generating unit 32.

[0026] The signal generating unit 31 generates a PWM signal Si2 (see FIG. 4). The "PWM signal" here is a rectangular wave signal used for pulse width modulation (PWM) control. In other words, the PWM signal Si2 is a rectangular signal that alternates between an H (High) level and an L (Low) level, and the sum of the time width T21 (see FIG. 5) of the H level and the time width of the L level is one period T20 (see FIG. 5).

[0027] The PWM signal Si2 enables PWM control by adjusting its duty ratio. The "duty ratio" here means the ratio of the H level period in the PWM signal Si2, and is expressed by dividing the H level time width T21 by the cycle T20 (=T21 / T20).

[0028] The voltage generating unit 32 generates a desired output voltage V1 (see FIG. 4). The output voltage V1 (high voltage) generated by the voltage generating unit 32 is applied independently to high-voltage driving parts such as the developing roller, the charging roller, and the transfer roller. Here, the voltage generating unit 32 can adjust the output voltage value (the magnitude of the output voltage V1) according to the PWM signal Si2 generated by the signal generating unit 31.

[0029] In this way, the power supply device 3 according to this embodiment constitutes the image processing device 10 together with the main body 1 of the image processing device 10. In other words, the image processing device 10 according to this embodiment includes the power supply device 3 and the main body 1 having an image processing function.

[0030] The image processing device 10 further includes a storage unit and a communication unit, etc. The storage unit includes one or more non-volatile memories, and stores information such as control programs for causing the main body control unit 16 to execute various processes in advance. The communication unit is an interface that executes data communication between the image processing device 10 and an external device connected via a communication network such as the Internet or a LAN (Local Area Network).

[0031] Incidentally, as a related technique for this type of image processing device 10, there is known an image processing device (image forming device) that incorporates a component such as a developing roller that requires a high voltage, and that is configured such that a high voltage output circuit of a power supply device (high voltage board) applies a predetermined high voltage to such a component. In the power supply device of the related technique, a voltage generating unit (high voltage output circuit) generates a high voltage that corresponds to the duty ratio of a PWM signal (rectangular signal) input from a signal generating unit (control board).

[0032] In the above related technology, the signal generating unit includes a controller that outputs a rectangular control signal, and a driver circuit that generates a PWM signal in response to a level change of the rectangular control signal and outputs the PWM signal to the voltage generating unit. The controller measures the duty of the PWM signal, identifies the difference between the duty of the rectangular control signal and the duty of the PWM signal, and corrects the duty of the rectangular control signal based on the identified difference.

[0033] However, the power supply device according to the above related art requires a circuit for measuring the duty cycle of the PWM signal, making it difficult to simplify the configuration and control of the power supply device.

[0034] In contrast, in this embodiment, a power supply device 3 and an image processing device 10 that can easily be simplified in configuration and control are provided by using the configuration described below.

[0035] [2] Power supply details Next, with reference to FIG. 1 and FIGS. 3 to 5, the configuration of the power supply device 3 that applies an output voltage V1 independently to each of the high voltage driving parts (such as the developing roller, charging roller, and transfer roller) will be described in more detail.

[0036] 1, the power supply device 3 according to this embodiment includes a correction unit 33 in addition to a signal generation unit 31 and a voltage generation unit 32. That is, the power supply device 3 includes the signal generation unit 31, the voltage generation unit 32, and the correction unit 33.

[0037] The voltage generating unit 32 of the power supply device 3 is configured to be able to adjust the output voltage value (the magnitude of the output voltage V1) according to the PWM signal Si2 generated by the signal generating unit 31, so that a change in the PWM signal Si2 changes the magnitude of the output voltage V1 of the power supply device 3. In other words, the magnitude of the output voltage V1 of the power supply device 3 is not constant but is variable according to the duty ratio of the PWM signal Si2 generated by the signal generating unit 31.

[0038] For example, as shown in Fig. 3, as the duty ratio increases (approaching 100%), the output voltage value increases. In the example of Fig. 3, the output voltage value increases approximately in proportion to the duty ratio, with an upper limit of 1500V peak-to-peak. In the example of Fig. 3, the target duty ratio is expressed by the following formula 1 using the target output voltage value v1, the slope a and the intercept b of the graph in Fig. 3 (duty ratio when the output voltage value is 0). Duty ratio [%] = v1 × a + b (Formula 1)

[0039] Specifically, in this embodiment, signal generating unit 31 and voltage generating unit 32 are provided separately on control board 310 and high voltage board 320, as shown in Fig. 4. That is, signal generating unit 31 is provided on control board 310, and voltage generating unit 32 is provided on high voltage board 320. Control board 310 and high voltage board 320 are electrically connected. In other words, power supply device 3 includes control board 310 including signal generating unit 31, and high voltage board 320 including voltage generating unit 32.

[0040] The signal generating unit 31 of the control board 310 includes, for example, a control unit 311 and a switch circuit 312. The switch circuit 312 is a circuit that can be controlled by an H-level or L-level digital signal input to a control terminal, and for example is a resistor-embedded transistor (a so-called digital transistor) that includes a switching element Tr1 made of a transistor, and resistors R1 and R2.

[0041] The control unit 311 includes a processor such as a CPU, and outputs a rectangular wave drive signal Si1 for driving the switch circuit 312. The drive signal Si1 is a rectangular signal that alternately repeats H level and L level, similar to the PWM signal Si2, and the sum of the time width of the H level and the time width T11 (see FIG. 5) of the L level is one period T10 (see FIG. 5). An output terminal of the drive signal Si1 in the control unit 311 is electrically connected to the switch circuit 312.

[0042] In the switch circuit 312, the base of the switching element Tr1 is electrically connected to the output terminal of the drive signal Si1 in the control unit 311 via a resistor R1. Furthermore, a resistor R2 is electrically connected between the base and emitter of the switching element Tr1. The emitter of the switching element Tr1 is connected to the circuit ground, and the collector of the switching element Tr1 is electrically connected to the high-voltage substrate 320.

[0043] The high voltage board 320 includes, for example, a voltage generating unit 32, a constant voltage source Vcc1, and a resistor R3. The constant voltage source Vcc1 is a voltage source that generates a predetermined DC voltage.

[0044] A PWM signal Si2 is input to the voltage generating unit 32. That is, the collector of the switching element Tr1 is electrically connected to the input terminal of the PWM signal Si2 in the voltage generating unit 32. Furthermore, a constant voltage source Vcc1 is electrically connected to the input terminal of the PWM signal Si2 in the voltage generating unit 32 via a resistor R3.

[0045] As a result, while (the switching element Tr1 of) the switch circuit 312 is off, an H-level PWM signal Si2 is input to the voltage generating unit 32, and while (the switching element Tr1 of) the switch circuit 312 is on, an L-level PWM signal Si2 is input to the voltage generating unit 32. Here, the switch circuit 312 is turned on and off by the drive signal Si1 from the control unit 311, and is turned on when the drive signal Si1 is at an H level and turned off when the drive signal Si1 is at an L level.

[0046] Therefore, according to the signal generating unit 31 configured as above, the PWM signal Si2, which is basically the inverse of the drive signal Si1 in terms of H level and L level, is input to the voltage generating unit 32. That is, as shown in Fig. 5, when the drive signal Si1 is at H level, the PWM signal Si2 is at L level, and when the drive signal Si1 is at H level, the PWM signal Si2 is at L level.

[0047] Therefore, the duty ratio (=T11 / T10) of the drive signal Si1, which is expressed by dividing the time width T11 of the L level of the drive signal Si1 by the period T10, actually corresponds to the duty ratio (=T21 / T20) of the PWM signal Si2, as shown in Fig. 5. The voltage generating unit 32 generates and outputs the output voltage V1, the magnitude of which (output voltage value) changes according to the duty ratio of the PWM signal Si2.

[0048] However, since the voltage values ​​used by the control board 310 and the high voltage board 320 are different, as described above, the signal generating unit 31 in the control board 310 performs open collector output. Furthermore, the switch circuit 312 such as a digital transistor has a characteristic that generates a delay time when it transitions from on to off (when it is turned off) due to its resistance component. As a result, the drive signal Si1 and the PWM signal Si2 are not completely synchronized, and a deviation may occur in the duty ratio between them.

[0049] 5, when the drive signal Si1 switches from H level to L level, the rising edge of the PWM signal Si2 (switching from L level to H level) is delayed by delay time T3 due to the effect of the delay time associated with turning off the switch circuit 312. As a result, the H level time width T21 of the PWM signal Si2 is shorter than the L level time width T11 of the drive signal Si1 by the delay time T3, and the duty ratio of the PWM signal Si2 (=T21 / T20) is slightly lower than the duty ratio of the drive signal Si1 (=T11 / T10).

[0050] As a result of the deviation in the duty ratio between the drive signal Si1 and the PWM signal Si2, a deviation may also occur in the value of the output voltage V1 (output voltage value) output from the voltage generating unit 32. In other words, if the duty ratio of the drive signal Si1 is set according to a target output voltage value, the duty ratio of the PWM signal Si2 at that time will be lower than the target duty ratio, and the value of the output voltage V1 output from the voltage generating unit 32 will also be lower by that amount.

[0051] Therefore, the duty ratio of the drive signal Si1 is set to a value taking into account the delay time of the switch circuit 312 (i.e., a value slightly higher than the target duty ratio), so that the duty ratio of the PWM signal Si2 is set to the target value.

[0052] As an example, assume that the frequency of the PWM signal Si2 is 10 kHz and the delay time T3 of the switch circuit 312 is 2.5 μs. In this case, the rising edge of the PWM signal Si2 is delayed by the delay time T3 with respect to one period T20 (=100 μs) of the PWM signal Si2, so the duty ratio of the PWM signal Si2 is 2.5% lower than the duty ratio of the drive signal Si1.

[0053] In this situation, to make the duty ratio of the PWM signal Si2 match the target value, the control unit 311 sets the duty ratio of the drive signal Si1 to a value obtained by adding a deviation value of 2.5% to the target value. This makes it possible to set the duty ratio of the PWM signal Si2 to the target value, and to make the output voltage value of the voltage generating unit 32 match the target value.

[0054] However, not only the duty ratio but also the frequency of the PWM signal Si2 may change. In this case, the period T20 of the PWM signal Si2 also changes, so the duty ratio of the PWM signal Si2 may deviate from the target value if the duty ratio of the drive signal Si1 is simply set to a value obtained by adding a predetermined deviation value to the target value.

[0055] Therefore, the correction unit 33 is configured to be able to correct the duty ratio of the PWM signal Si2. That is, the PWM signal Si2 generated by the signal generation unit 31 and output to the voltage generation unit 32 can have its duty ratio corrected by the correction unit 33. Here, the correction unit 33 obtains a correction value of the duty ratio according to the frequency or period T20 of the PWM signal Si2. The correction unit 33 corrects the duty ratio of the PWM signal Si2 based on the obtained correction value. The "frequency" of the PWM signal Si2 here is represented by the reciprocal (1 / T20) of the period T20 of the PWM signal Si2. In this embodiment, the control unit 311 is an example of the correction unit 33.

[0056] According to this configuration, the PWM signal Si2 is corrected taking into consideration the change in the frequency (or period T20) of the PWM signal Si2, so that even if the frequency of the PWM signal Si2 changes, it is possible to set the duty ratio of the PWM signal Si2 to the target value. As a result, it is possible to make the output voltage value of the voltage generating unit 32 to the target value. Moreover, this configuration does not require a circuit for measuring the duty ratio of the PWM signal Si2, which has the advantage of making it easier to simplify the configuration and control compared to the related art.

[0057] More specifically, the correction unit 33 obtains a correction value for the duty ratio based on the frequency of the PWM signal Si2 and the delay time T3 of the switch circuit 312. For example, the correction value A1 [%] is expressed by the following formula 2 based on the frequency F1 [Hz] of the PWM signal Si2 and the delay time T3 [s] of the switch circuit 312. A1=F1×T3×100 (Formula 2)

[0058] The correction unit 33 adds the correction value A1 calculated by the above formula 2 to the target value to obtain the duty ratio of the drive signal Si1. As a result, the duty ratio of the PWM signal Si2 is corrected to the target value.

[0059] As an example, assume that the frequency of the PWM signal Si2 changes from 10 kHz to 20 kHz when the delay time T3 of the switch circuit 312 is 2.5 μs as described above. In this case, the rising edge of the PWM signal Si2 is delayed by the delay time T3 with respect to one period T20 (=50 μs) of the PWM signal Si2, so the duty ratio of the PWM signal Si2 is 5% lower than the duty ratio of the drive signal Si1. In this situation, the correction unit 33 calculates the correction value A1 to be 5% (=10000×0.000005×100) using the above formula 2.

[0060] The correction unit 33 adds the correction value A1 (5%) calculated in this way to the target value to determine the duty ratio of the drive signal Si1. That is, the deviation in the duty ratio caused by the delay time T3 can be offset by the correction value A1, so that the duty ratio of the PWM signal Si2 is corrected to the target value.

[0061] As described above, in this embodiment, the correction unit 33 (control unit 311) obtains the correction value A1 according to the delay time T3 occurring in the switching element Tr1 of the signal generation unit 31. Therefore, when a deviation in the duty ratio occurs due to the delay time T3 inherent to the switching element Tr1 of the signal generation unit 31 that generates the PWM signal Si2, the correction unit 33 can make a correction taking this deviation into consideration.

[0062] Incidentally, the delay time T3 used when calculating the correction value A1 by the above formula 2 is not necessarily a constant value. That is, if the temperature of the switching element Tr1 changes due to the temperature characteristics of the switching element Tr1 or the like, the delay time T3 of the switch circuit 312 may also change.

[0063] Therefore, the correction unit 33 (control unit 311) uses a value for the delay time T3 that varies depending on the temperature of the switching element Tr1. That is, the correction unit 33 calculates the correction value A1 according to the above formula 2 using the delay time T3 corresponding to the temperature of the switching element Tr1. This makes it possible to obtain a more appropriate correction value A1 taking into account the temperature of the switching element Tr1, thereby improving the accuracy of the duty ratio correction.

[0064] Specifically, as shown in FIG. 6, the control board 310 is further provided with a storage unit 313, a constant voltage source Vcc2, a resistor R4, and a temperature sensor S1.

[0065] The storage unit 313 prestores information on the correspondence between the delay time T3 and the temperature of the switching element Tr1. For example, the information is written in the storage unit 313 by measuring the delay time T3 of the switching element Tr1 under various temperature environments and associating the measurement results with each temperature. For example, the information is stored in a table format, and when a certain temperature is specified, the control unit 311 can read out the corresponding delay time T3 from the storage unit 313.

[0066] The temperature sensor S1 is, for example, a thermistor. The temperature sensor S1 is electrically connected to a constant voltage source Vcc2 via a resistor R4, and is configured so that the voltage across the temperature sensor S1 is input to the control unit 311. The temperature sensor S1 is mounted in the vicinity of the switching element Tr1 on the control board 310 in a state where it is thermally coupled to the switching element Tr1 so as to be able to detect the temperature of the switching element Tr1.

[0067] This allows the control unit 311 to detect the temperature of the switching element Tr1 from the output (voltage across both ends) of the temperature sensor S1. The control unit 311 reads out the delay time T3 corresponding to the temperature of the switching element Tr1 indicated by the output of the temperature sensor S1 from the storage unit 313. The control unit 311 calculates the correction value A1 by the above formula 2 using the delay time T3 read out from the storage unit 313.

[0068] In short, the correction unit (control unit 311) obtains the delay time T3 using a pre-stored correspondence relationship between the delay time T3 and the temperature of the switching element Tr1, and the output of the temperature sensor S1 that detects the temperature of the switching element Tr1. This makes it possible to easily obtain the delay time T3 that reflects the temperature of the switching element Tr1.

[0069] Here, the temperature sensor S1 for detecting the temperature of the switching element Tr1 is not limited to a configuration that directly detects the temperature of the switching element Tr1. For example, when there is no large difference between the ambient temperature of the switching element Tr1 and the outside air temperature around the main body 1, the temperature sensor S1 may detect the temperature of the switching element Tr1 by detecting the outside air temperature. In this case, the memory unit 313 stores the correspondence relationship between the delay time T3 and the outside air temperature as the correspondence relationship between the delay time T3 and the temperature of the switching element Tr1.

[0070] [3] Variations The multiple components included in the power supply device 3 may be distributed across multiple housings. For example, at least one of the signal generating unit 31, the voltage generating unit 32, and the correcting unit 33 may be provided separately.

[0071] 4 and 6, the specific configuration of the power supply device 3 is not limited to the configuration shown in Fig. 4 and 6, and can be modified as appropriate as long as the same functions can be realized. For example, the control board 310 and the high voltage board 320 may be integrated into a single board. [Explanation of symbols]

[0072] 1 Main unit 3 Power supply 10 Image processing device 31 Signal Generation Unit 32 Voltage generation unit 33 Correction section 311 Control unit (correction unit) S1 Temperature Sensor Si2 PWM signal T3 delay time Tr1 switching element

Claims

1. A signal generating unit that generates a PWM signal; a voltage generating unit whose output voltage value is adjusted in response to the PWM signal; a correction unit that obtains a correction value of a duty ratio corresponding to a frequency or a period of the PWM signal and corrects the duty ratio of the PWM signal based on the correction value. power supply.

2. The correction unit determines the correction value according to a delay time caused by a switching element of the signal generation unit.

2. The power supply device of claim 1.

3. The correction unit uses a value that varies depending on a temperature of the switching element as the delay time.

3. The power supply device of claim 2.

4. The correction unit calculates the delay time by using a correspondence relationship between the delay time and the temperature of the switching element that is stored in advance and an output of a temperature sensor that detects the temperature of the switching element.

4. The power supply device of claim 3.

5. A power supply device according to any one of claims 1 to 4, A main body having an image processing function. Image processing device.

Images