JP7059815B2 - Image forming device - Google Patents

Description

The present disclosure relates to an image forming apparatus.

A first output unit (for example, a main converter) that outputs a first voltage, and a second output unit (for example, a second output unit) that outputs a voltage from the first output unit and outputs a second voltage lower than the first voltage. , DCDC converter) and an image forming apparatus have been proposed. In Patent Document 1, this second output unit has a switch unit, and by continuously executing on / off (switching) of the switch unit, the voltage from the first output unit is converted into a second voltage. Is disclosed to be output. Further, the image forming apparatus of Patent Document 1 is controlled to a power saving state. The power saving state is a state in which the switch unit is not turned on and off by setting the voltage from the first output unit to a voltage lower than the second voltage.

Japanese Patent No. 5268615

However, in the image forming apparatus described in Patent Document 1, no consideration has been given to the control of the voltage value of the voltage output from the second output unit in the power saving state. Therefore, during the power saving state, the second output unit could not output a voltage having an appropriate voltage value.

The present disclosure has been conceived in view of such circumstances, and an object thereof relates to an image forming apparatus that outputs a voltage having an appropriate voltage value from a second output unit during a power saving state.

According to a certain aspect of the present disclosure, the voltage is smaller than the first voltage and the first output is obtained by having a first output unit for outputting the first voltage and a switch unit and performing switching control of the switch unit. It is equipped with a second output unit that outputs the second voltage from the unit and a state control unit that controls the power saving state, and the second output unit measures the maximum voltage among the voltages at which the switching control of the switch unit is stopped. , An image forming apparatus is provided that outputs a second voltage when controlled to a power saving state.

Preferably, the switching control is performed when the first adjusting unit increases the second voltage by one step each time a predetermined period elapses during the power saving state, and when the second voltage is increased by one step by the first adjusting unit. It is equipped with a first judgment unit that determines whether or not it has been stopped, and the first adjustment unit further increases the second voltage by one step when the first determination unit determines that switching control has been stopped. When the first determination unit determines that the switching control has not been stopped, the second voltage is further reduced by one step, and the second output section reduces the second voltage by one step by the first adjustment section. It is output as a new second voltage.

Preferably, a period changing unit for changing a predetermined period is further provided according to a predetermined factor.
Preferably, the predetermined factor includes the temperature in the image forming apparatus.

Preferably, during the power saving state, the second output unit drives the load, and predetermined factors include the start of the load drive and the end of the load drive.

Preferably, when the second determination unit for determining whether or not the switching control is stopped and the second determination unit for determining whether the switching control is not stopped, the second voltage is reduced by one step. The second adjusting unit includes an adjusting unit, and the second adjusting unit reduces the second voltage output from the second output unit by one step until the second determining unit determines that the switching control has been stopped. , The second output unit outputs the second voltage when the second determination unit determines that the switching control of the switch unit has been stopped as a new second voltage.

Preferably, the state control unit controls the detection state to detect the maximum voltage, and the processing of the second adjustment unit and the processing of the second determination unit are executed during the detection state.

Preferably, the processing of the second adjusting unit and the processing of the second determination unit are executed when the power saving state is controlled.

According to the present disclosure, a voltage having an appropriate voltage value is output from the second output unit during the power saving state.

It is a figure which shows the whole structure of an image forming apparatus. It is a figure which shows the hardware composition of the image forming apparatus. It is a figure which shows the structure of the power supply device of this embodiment. It is a figure which shows the correspondence between a power supply device and a load. It is a figure which shows the structure of the power supply device of the comparative example. It is a figure which shows the output voltage from the 1st output part of the comparative example. It is a figure which shows the output voltage from the 1st output part of this embodiment. It is a flowchart of power saving state control processing. It is a flowchart of power saving transition control processing. It is a flowchart of a detection mode. It is a figure which shows the relationship between the temperature in an image forming apparatus, and a reset interval. It is a figure which shows the relationship between the current output to a load, and a reset interval.

The image forming apparatus according to the embodiment based on the present invention will be described below with reference to the drawings. When the number, quantity, etc. are referred to in the embodiments described below, the scope of the present invention is not necessarily limited to the number, quantity, etc., unless otherwise specified. The same reference number may be assigned to the same part or equivalent part, and duplicate explanations may not be repeated. In addition, it is planned from the beginning to use the configurations in each embodiment in appropriate combinations.

[First Embodiment]
A schematic configuration of the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a diagram showing an internal configuration of the image forming apparatus 100.

FIG. 1 shows an image forming apparatus 100 as a color printer. Hereinafter, the image forming apparatus 100 as a color printer will be described, but the image forming apparatus 100 is not limited to the color printer. For example, the image forming apparatus 100 may be a monochrome printer, or may be a monochrome printer, a color printer, and a multifunction device (MPB: Multi-Functional Peripheral).

The image forming apparatus 100 includes image forming units 1A to 1D as forming portions, an intermediate transfer belt 11, a primary transfer roller 12, a secondary transfer roller 13, a cleaning portion 15, a paper ejection tray 16, and a cassette 17. A control unit 18, an exposure control unit 19, a fixing device 30 as a fixing unit, a paper ejection roller 36, an inverting transfer path 38, a power supply device 110, and the like are included. In addition, in FIG. 1, for convenience, the power supply device 110 is described as being installed inside the image forming device 100. However, the power supply device 110 may be installed outside the image forming apparatus 100, for example, on the back surface of the image forming apparatus 100.

The image forming unit 1A forms a yellow (Y) toner image. The image forming unit 1B forms a toner image of magenta (M). The image forming unit 1C forms a toner image of cyan (C). The image forming unit 1D forms a black (BK) toner image.

The intermediate transfer belt 11 is an endless belt, and is driven in the direction of the arrow 21 by rotating at least one of the plurality of support rollers. The image forming units 1A to 1D are arranged in order along the driving direction of the intermediate transfer belt 11, respectively.

The image forming units 1A to 1D include a photoconductor 2, a charging unit 3, a developing unit 4, a photoconductor cleaning unit 5, and an exposure unit 9, respectively. The photoconductor 2 is an image carrier that supports a toner image. As an example, as the photoconductor 2, a photoconductor drum having a photosensitive layer formed on the surface thereof is used. The photoconductor 2 rotates in a direction corresponding to the driving direction of the intermediate transfer belt 11.

The charging unit 3 uniformly charges the surface of the photoconductor 2. The exposure unit 9 irradiates the photoconductor 2 with a laser beam in response to a control signal from the exposure control unit 19, and exposes the surface of the photoconductor 2 according to a designated image pattern. As a result, an electrostatic latent image corresponding to the designated image pattern is formed on the photoconductor 2.

The developing unit 4 develops an electrostatic latent image formed on the photoconductor 2 as a toner image. As an example, the developing unit 4 develops an electrostatic latent image using a two-component developer composed of toner and a carrier.

The toner image formed on the surface of the photoconductor 2 is transferred to the intermediate transfer belt 11 by the primary transfer roller 12. At this time, the yellow (Y) toner image, the magenta (M) toner image, the cyan (C) toner image, and the black (BK) toner image are superimposed in this order and transferred to the intermediate transfer belt 11. As a result, a color toner image is formed on the intermediate transfer belt 11.

The photoconductor cleaning unit 5 includes a cleaning blade. The cleaning blade is pressed against the photoconductor 2 and collects the toner remaining on the photoconductor 2 after the transfer of the toner image.

The primary transfer roller 12 transfers the toner image developed on the photoconductor 2 to the intermediate transfer belt 11. The photoconductor 2 and the intermediate transfer belt 11 are in contact with each other at a portion where the primary transfer roller 12 is provided. A predetermined transfer bias (voltage) is applied to this contact portion, and the toner image on the photoconductor 2 is transferred to the intermediate transfer belt 11 by this transfer bias.

The cassette 17 is provided in the lower part of the image forming apparatus 100. Paper 14 such as paper is set in the cassette 17. The paper 14 is sent from the cassette 17 to the secondary transfer roller 13 one by one. By synchronizing the timing of feeding and transporting the paper 14 with the position of the toner image on the intermediate transfer belt 11, the toner image is transferred to an appropriate position on the paper 14. After that, the paper 14 is sent to the fixing device 30.

The fuser 30 melts the toner image (unfixed toner image) transferred to the paper 14 by heat, and fixes the toner image on the paper 14. The fuser 30 sandwiches the fixing roller 32 as a heating member heated by the heating heater 32h as a heating device and the paper 14 on which the unfixed image is formed on the surface together with the fixing roller 32, and is between the fixing roller 32. A pressure roller 31 as a pressure member for fixing an unfixed image on the paper 14 while passing through the paper 14 and a fixing temperature detecting unit 33 are provided. The fixing temperature is controlled by the control unit 18 based on the detection result of the fixing temperature detecting unit 33.

Further, the image forming apparatus 100 can receive the user's input from the operation unit 50. The job includes, for example, a single-sided printing job (a job for single-sided printing), a double-sided printing job (a job for double-sided printing), a scan job (a job for scanning), and the like.

When a single-sided printing job is input by the user, the paper 14 is discharged to the paper ejection tray 16 by the paper ejection roller 36 after the fixing process by the fixing device 30. When a double-sided printing job is input by the user, the paper 14 is sent to the reverse transfer path 38 by the reverse rotation of the paper ejection roller 36 after the fixing process by the fixing device 30. After that, the paper is sent to the secondary transfer roller 13 so that the toner image is transferred to the back surface (second side) of the paper. The secondary transfer roller 13 transfers the toner image to an appropriate position on the back surface of the paper 14. After that, it is sent to the fixing device 30 again, and the fixing device 30 fixes the toner image on the back surface of the paper. In this way, when a double-sided printing job is input by the user, it is possible to print on both sides.

The cleaning unit 15 includes a cleaning blade. The cleaning blade is pressed against the intermediate transfer belt 11 and collects the toner particles remaining on the intermediate transfer belt 11 after the toner image is transferred. The toner particles are transported by a transport screw (not shown) and collected in a waste toner container (not shown).

The control unit 18 controls the image forming process of the image forming apparatus 100. The control unit 18 controls the image forming units 1A to 1D, the secondary transfer roller 13, the fuser 30 (temperature control of the heater 32h, the rotation speed of the pressurizing roller 31, etc.), the exposure control unit 19, and the like.

Further, a cooler 55 is provided downstream of the fuser 30. The cooler 55 includes a cooling roller 52 (cooling portion) and an opposing roller 51 (opposing portion). The cooler 55 is controlled by the control unit 18. The facing roller 51 faces the cooling roller 52, and the facing roller 51 and the cooling roller 52 hold the paper.

In this way, the facing roller 51 and the cooling roller 52 hold the paper and cool the paper, so that the paper can be cooled stably.

Further, the power supply device 110 outputs (supplys) a voltage (electric power) to each part (each load) in the image forming apparatus 100.

[Hardware configuration]
FIG. 2 is a diagram showing a hardware configuration of the image forming apparatus 100. With reference to FIG. 2, the image forming apparatus 100 includes a CPU (Central Processing Unit) 101 for executing a program, a ROM (Read Only Memory) 102 for storing data non-volatilely, and a RAM for storing data volatilely. (Random Access Memory) 103, flash memory 104, speaker 106, communication IF (Interface) 108, IC (Integrated Circuit) card reader / writer 109, power supply device 110, control system load 202, and drive system load. It is equipped with 204.

The flash memory 104 is a non-volatile semiconductor memory. The flash memory 104 stores an operating system executed by the CPU 101, various programs, various contents, and data. Further, the flash memory 104 volatilely stores various data such as data generated by the image forming apparatus 100 and data acquired from an external device of the image forming apparatus 100.

The speaker 106 generates sound in response to a command from the CPU 101. The communication IF 108 is an interface used for communicating with other devices. The communication IF 108 performs processing for transmitting data wirelessly and / or by wire.

The control system load 202 is a load (part) that controls each part of the image forming apparatus 100. The control system load 202 includes, for example, an operation unit 50, a control unit 18 (see FIG. 1) that controls image formation processing, a memory (ROM 102, etc.), a communication port (for example, communication IF 108, etc.), and the like. .. The operation unit is composed of a display as a display device and a touch panel as an input device. Specifically, the operation unit is realized by positioning and fixing the touch panel on the display (for example, a liquid crystal display). The touch screen is also referred to as a touch panel display, a display with a touch panel, or a touch panel monitor. In the operation unit 50, for example, a resistance film method or a capacitance method can be used as the touch position detection method.

The touch panel is an input device that accepts input (touch input) by a user's finger, a stylus pen, or the like. The CPU 101 specifies an input position based on the output from the touch panel, and displays a screen based on the specified input position.

The drive system load 204 is, for example, a load (part) driven by the control system load 202. The drive system load 204 includes an image forming unit 1A to 1D, a motor for driving a feeding unit (not shown) for feeding paper from the cassette 17 to the image forming units 1A to 1D, a clutch, and the like. In FIG. 2, for convenience, the ROM 102 and the communication IF 108 and the control system load 202 are shown separately.

The processing in the image forming apparatus 100 is realized by each hardware and software executed by the CPU 101. Such software may be stored in the flash memory 104 in advance. Further, the software may be stored in a memory card 1091 or other storage medium and distributed as a program product. Alternatively, the software may be provided as a downloadable program product by an information provider connected to the so-called Internet. Such software is read from the storage medium by an IC card reader / writer 109 or other reading device, or downloaded via a communication IF, and then temporarily stored in the flash memory 104. The software is read from the flash memory 104 by the CPU 101 and further stored in the flash memory 104 in the form of an executable program. The CPU 101 executes the program.

It can be said that the software used in the image forming apparatus 100 is software stored in a flash memory 104, a memory card 1091 or other storage medium, or software that can be downloaded via a network.

The storage medium is not limited to DVD-ROM, CD-ROM, FD (Flexible Disk), and hard disk, but also magnetic tape, cassette tape, optical disc (MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital). Versatile Disc))), optical cards, mask ROMs, EPROMs (Electronically Programmable Read-Only Memory), EEPROMs (Electronically Erasable Programmable Read-Only Memory), flash ROMs, and other semiconductor memories that carry programs in a fixed manner may be used. .. Further, the recording medium is a non-temporary medium in which the program or the like can be read by a computer.

The program referred to here includes not only a program that can be directly executed by the CPU, but also a source program format program, a compressed program, an encrypted program, and the like.

[Configuration of power supply device 110]
Next, an example of the configuration of the power supply device 110 will be described. FIG. 3 is a diagram showing an example of the configuration of the power supply device 110. The power supply device 110 is controlled by a main converter (hereinafter referred to as "first output unit 112"), a DC (Direct Current) DC converter (hereinafter referred to as "second output unit 114"), and a switch unit 116. The unit 120 and the like are included.

The first output unit 112 can output either a voltage of 24 V (first voltage) or a voltage of 5 V (second voltage) to the drive system load. The second output unit 114 (second output unit) outputs 5V (second voltage) to the control system load.

The switch unit 116 can be switched on and off by the control of the control unit 120. When the switch unit 116 is on, the voltage is output from the first output unit 112. When the switch unit 116 is off, the voltage is not output from the first output unit 112.

The control unit 120 includes a first adjustment unit 122, a first determination unit 124, a second adjustment unit 126, a second determination unit 128, a state control unit 130, a temperature detection unit 132, and an interval changing unit 134. including. The temperature detection unit 132 and the interval changing unit 134 will be described with reference to the third embodiment and the fourth embodiment. The state control unit 130 controls the image forming apparatus 100 to one of a plurality of states (states). The plurality of states include an operating state, a standby state, and a power saving state (power saving state).

The operating state is a state in which the image forming apparatus 100 is operating (operating). The operating state includes, for example, a state in which the image forming apparatus 100 is executing an image forming process (also referred to as a print process). The standby state is a state in which the image forming apparatus 100 is not executing any processing. That is, it is controlled to the standby state from the time when the operating state ends. During the operating state and the standby state, the first output unit 112 outputs a first voltage of 24V. Further, the second output unit 114 outputs a second voltage of 5 V during the operating state and the standby state.

Further, when the standby state is controlled for a predetermined period (for example, 5 minutes), the power saving state is controlled. The power saving state is a state that is established when a predetermined power saving condition is satisfied. The power saving state is established when the first condition is satisfied when the time reaches a predetermined time (for example, the time at midnight) and when the user inputs a predetermined power saving operation to the operation unit 50. The second condition is included.

Next, the configurations of the first output unit 112 and the second output unit 114 will be described. The first output unit 112 is connected to the commercial power supply 10. The first output unit 112 includes a rectifier 1124, a smoothing capacitor 1126, a transformer 1128, a feedback unit 1130, a control IC 1132 (Integrated Circuit), and the like.

When an AC voltage (AC voltage) is applied from the commercial power supply 10, the smoothing capacitor 1126 is charged by the voltage rectified by the rectifier 1124. The commutator 1124 and the smoothing capacitor 1126 function as a rectifying smoothing circuit that rectifies and smoothes the AC voltage from the AC power supply. The rectified and smoothed voltage is supplied to transformer 1128. Further, the feedback unit 1130 stabilizes the output voltage from the first output unit 112 by executing feedback control corresponding to the voltage output of 24 V to the control IC 1132.

The second output unit 114 is connected to the first output unit 112. The second output unit 114 includes a FET 1142 (Field effect transistor), a control IC 1144, and a feedback unit 1146. If the FET 1142 has a switching function, another member may be used. For example, a bipolar transistor may be used instead of the FET 1142.

In order to output a voltage of 5V, the second output unit 114 continuously drives the FET 1142 (repeated on / off) by the feedback control of the feedback unit 1146. The FET 1142 is also referred to as a switch unit. By this continuous drive, the voltage of 24V from the first output unit 112 is converted (generated) to 5V. This continuous drive is also called switching control or on / off control. By switching control, the second output unit 114 outputs a voltage of 5V. In the operating state and the standby state, a voltage of 24V is output from the first output unit 112, and a voltage of 5V is output from the second output unit 114.

Further, when the switching control is executed, the FET 1142 transmits a switching pulse as a detection signal to the control unit 120. When the ON / OFF control is executed once, the FET 1142 transmits a switch pulse, which is one pulse, to the control unit 120 as a detection signal.

If the voltage supplied from the first output unit 112 to the second output unit 114 is 5 V or more, for example, the control unit 120 causes the FET 1142 to execute switching control. By the switching control, the voltage of 5V or more from the first output unit 112 is lowered, and the second output unit 114 outputs a voltage of 5V.

If the voltage supplied from the first output unit 112 to the second output unit 114 is less than 5V, for example, the control unit 120 keeps the FET 1142 in the ON state without causing the FET 1142 to execute switching control. By continuing the ON state of the FET 1142, the second output unit 114 outputs a voltage of less than 5 V from the first output unit 112.

The processing of the first adjustment unit 122, the first determination unit 124, the second adjustment unit 126, and the second determination unit 128 will be described later.

The control unit 120 outputs a voltage variable signal to the feedback unit 1130. The voltage variable signal is, for example, a PWM (Pulse Width Modulation) signal. The PWM signal contains, for example, information indicating a duty ratio. The feedback unit 1130 can output a voltage corresponding to the duty ratio from the second voltage. FIG. 4 is a diagram showing a load to which a voltage is output. As shown in FIG. 4, a voltage of 24V is output from the first output unit 112 to the drive system load 204 (24V load) via the switch unit 116. The drive system load 204 is, for example, a motor, a clutch, or the like. Further, a voltage of 5V is output from the second output unit 114 to the control system load 202 (5V load). The control system load 202 is, for example, an image formation control unit that controls image formation processing, an operation unit 50, a communication IF 108, and the like.

[Image forming apparatus of comparative example]
FIG. 5 is a diagram showing a power supply device of the image forming apparatus of the comparative example. As for the reference code of the power supply device of the comparative example of FIG. 5, "A" is added to the reference code of each component described in FIG. Further, FIG. 6 shows the output voltage and the like from the first output unit 112A in the power supply device of the image forming apparatus of the comparative example. FIG. 6A shows the output of the voltage switching signal (see FIG. 5). While the voltage switching signal is transmitted to the first output unit 112A, the first output unit 112A outputs the first voltage. When the transmission of the voltage switching signal to the first output unit 112A is stopped, the first output unit 112A starts the control to reduce the output voltage.

FIG. 6B shows the output voltage from the first output unit 112A. FIG. 6C shows the output voltage from the second output unit 114A. FIG. 6D shows the state of FET 1142A. One vertical line in FIG. 6D indicates that the FET 1142A has performed switching control once. In other words, one vertical line in FIG. 6D indicates a switchon pulse for switching control of the FET 1142A. From timing T0 to timing T1, vertical lines are densely packed, indicating that the FET 1142A frequently performs switching control. The horizontal axis indicates time T.

In the example of FIG. 6, in the standby state (timing T0 to T1), the first output unit 112A outputs a voltage of 24V (first voltage), and the second output unit 114A outputs a voltage of 5V. There is. Further, it is assumed that the power saving condition is satisfied at the timing T1 in the standby state. In this case, as shown in FIG. 5A, at the timing T1, the control unit 120A stops the transmission of the voltage signal switching signal to the feedback unit 1130A.

When the control unit 120A stops transmitting the voltage signal switching signal to the feedback unit 1130A, the feedback control is executed for the control IC 1132A. This feedback control is a control for outputting a voltage of "5-α" (referred to as "third voltage" in the example of FIG. 6) from the second output unit 114A. However, it is assumed that 0 <α <5.

In FIG. 6, the period in which the voltage drops from 24V to the third voltage (5-α) is the transition period (the period from timing T1 to timing T2). Since the output voltage from the second output unit 114A drops during this transition period, the execution frequency of the switching control of the FET 1142A is lower than the execution frequency in the standby state (FIG. 6). The number of vertical lines in (D) is decreasing). It is assumed that the output voltage from the first output unit 112A reaches "5-α" at the timing T2.

Here, as shown in FIG. 6, the FET 1142A is used from the timing T2 at which the control to the power saving state is started, that is, the timing T2 at which the output voltage from the first output unit 112A reaches "5-α". Switching control is stopped. That is, the FET 1142A is in a state of total conduction of the FET. In this way, it is considered that the efficiency of electric power in the power saving state can be improved by becoming the fully conductive state.

However, when the value of α is small, that is, when the potential difference between the second voltage and the third voltage is small, the stopped switching control may be executed. The reason why the switching control that has been stopped is executed is the temperature fluctuation of the parts related to the voltage setting (voltage stabilization). The component related to the voltage setting is, for example, a component in the feedback unit 1130A. This component is, for example, a feedback resistor included in the feedback unit 1130A, a reference voltage reduction, an error amplifier (operational amplifier), and the like. The execution of switching control is also due to the component constants related to the voltage setting (voltage stabilization). The component constant is a constant associated with each of the components.

On the other hand, when the value of α is large, that is, when the potential difference between the second voltage and the third voltage is large, the voltage value from the second output unit 114A sets the lower limit of the allowable voltage range (tolerance) of 5V. It may fall below. Here, the lower limit of the allowable voltage range of 5V is, for example, "4.85V" obtained by subtracting "0.15V", which is a value of 3% of 5V, from 5V. If the voltage value from the second output unit 114A falls below the lower limit of the allowable voltage range of 5V, the control parts corresponding to the second output unit 114A malfunction, and the system operation is stopped or the parts are damaged. Etc. may occur. In the example of FIG. 4, the control component corresponding to the second output unit 114A is an image formation control unit or the like, which is a control load. As described above, in the image forming apparatus 100A of the comparative example, the second output unit 114A cannot output a voltage having an appropriate voltage value during the power saving control.

[Image forming apparatus of this embodiment]
FIG. 7 shows the output voltage and the like from the first output unit 112 in the power supply device 110 of the image forming apparatus of the present embodiment. FIG. 7A shows the output of the voltage variable signal.

FIG. 7B shows the output voltage from the first output unit 112. FIG. 7C shows the output voltage from the second output unit 114. FIG. 7D shows the state of the detection signal (switching pulse signal) from the FET 1142. One vertical line in FIG. 7D indicates that the FET 1142A has performed switching control once. For example, since the vertical lines are densely packed from timing T0 to timing T11, the FET 1142 frequently performs switching control, and frequently transmits a detection signal (switching pulse signal) to the control unit 120. It shows that there is.

During the period from timing T11 to timing T12, the first output unit 112 lowers the first voltage, which is 24V, to the second voltage, which is 5V. The state control unit 130 controls the power saving state from the timing T12. In the present embodiment, the time α from the timing T11 to the timing T12, that is, the time α until the output voltage of the first output unit 112 drops from 24V to 5V is measured in advance by a developer or the like. Then, when the time α elapses from the timing T11 at which the standby mode ends, the state control unit 130 controls the power saving state. According to such a configuration, a measuring unit for measuring the voltage value of the voltage output from the first output unit 112 is not required. Therefore, the number of parts can be reduced.

Here, at the timing T12, since the voltage value of the voltage from the first output unit 112 is lowered, the switching control by the FET 1142 may be executed. Therefore, in the present embodiment, the output voltage from the first output unit 112 is controlled so that the switching control by the FET 1142 is not executed.

An example of this control will be described. When controlled to the power saving state, the second determination unit 128 of the control unit 120 determines whether or not the switching control of the FET 1142 (switch unit) has been stopped. When the detection signal from the FET 1124 is received, the second determination unit 128 determines that the switching control of the FET 1142 has not been stopped (the switching control is being executed). On the other hand, the second determination unit 128 determines that the switching control of the FET 1142 is stopped when the detection signal from the FET 1124 is not received.

The second adjusting unit 126 of the control unit 120 determines the second voltage output from the second output unit 114 when the second determination unit 128 determines that the switching control of the FET 1142 (switch unit) has not been stopped. Decrease to the maximum voltage. Here, the maximum voltage means the maximum voltage among the voltages equal to or lower than the stop voltage at which the switching control of the FET 1142 is stopped. This maximum voltage is also referred to as a "switching stop voltage" (see step S26 in FIG. 9).

Further, it can be said that the "second voltage output from the second output unit 114", which is the target of the increase of the second adjustment unit 126, is the voltage from the first output unit 112. Therefore, it can be said that the target of the increase of the second adjusting unit 126 is the “voltage output from the first output unit 112 (second voltage)”.

In the power saving state, when the second output unit 114 outputs the maximum voltage as the second voltage, the switching control of the FET 1142 is not executed. Therefore, "the switching control of the FET 1142 is performed during the power saving state. The efficiency of the power saving state can be improved as compared with the "executed image forming apparatus". In addition, since the voltage does not fall below the lower limit of the allowable voltage range of 5V, which is "4.85V", the control component (see FIG. 4) corresponding to the second output unit 114 malfunctions, causing the system operation to stop. It is possible to reduce the occurrence of damage to parts.

Hereinafter, the processing of the second adjusting unit 126 and the second determination unit 128 will be further described. When the second determination unit 128 determines that the switching control of the FET 1142 is not stopped, the second adjustment unit 126 reduces the second voltage step by step until the maximum voltage (switching stop voltage) is reached.

The "one step" is the minimum value of the voltage that can be increased by the second adjusting unit 126. This minimum value (one-step value) is determined based on, for example, the resolution of the control unit 120 or the like. For example, if the resolution of the control unit 120 or the like is high, this minimum value can be reduced and the second voltage can be finely increased. On the other hand, if the resolution of the control unit 120 or the like is low, this minimum value becomes large.

Further, to be described in detail, the second adjusting unit 126 lowers the second voltage by one step when the second determining unit 128 determines that the switching control of the FET 1142 is not stopped. The second determination unit 128 determines whether or not the switching control of the FET 1142 is stopped after the second adjustment unit 126 lowers the second voltage by one step. When it is determined that the switching control of the FET 1142 has been stopped, the control unit 120 sets the second voltage when the second determination unit 128 determines that the switching control of the FET 1142 has been stopped to a new second voltage (that is, the maximum). (Switching stop voltage)) is output from the second output unit 114 (the voltage from the second output unit 114 is reset).

On the other hand, when it is determined that the switching control of the FET 1142 is not stopped, the second adjusting unit 126 further lowers the second voltage by one step. Then, the process of determining whether or not the switching control of the FET 1142 is stopped and the process of lowering the second voltage by one step are repeated. The control unit 120 repeats the determination process and the lowering process until the second determination unit 128 determines that the switching control of the FET 1142 has been stopped. That is, the second adjusting unit reduces the second voltage step by step until the second determining unit 128 determines that the switching control of the FET 1142 has been stopped. When the second determination unit 128 determines that the switching control of the FET 1142 has been stopped, the control unit 120 uses the second voltage at the time of the determination as a new second voltage (that is, the maximum voltage) as the second voltage. It is output from the output unit 114.

Next, the control during the power saving state will be described. The first adjusting unit 122 increases the second voltage by one step every predetermined period. Here, the predetermined period means the resetting interval shown in FIG. 7 (D). The first adjusting unit 122 increases the second voltage by one step at the timing for each resetting interval (timing T13, T14, T15, T16 ... In FIG. 7). Next, the first determination unit 124 determines whether or not the switching control is stopped when the second voltage is increased by one step by the first adjustment unit 122. This determination is performed using the detection signal transmitted from the FET 1142, similarly to the second determination unit 128.

Further, the first adjusting unit 122 further increases the second voltage by one step when the first determining unit 124 determines that the switching control is stopped. The first adjusting unit 122 increases the second voltage step by step until the first determining unit 124 determines that the switching control has not been stopped.

After that, when the first determination unit 124 determines that the switching control has not been stopped, the first adjustment unit 122 further reduces the second voltage by one step. The second output unit outputs the second voltage reduced by one step by the first adjusting unit 122 as a new second voltage.

[Flow chart of image forming apparatus 100]
8 and 9 show a flowchart when the image forming apparatus 100 controls the power saving state. A flowchart when the power is controlled to a power saving state will be described with reference to FIGS. 8 and 9.

First, in step S2 of FIG. 8, the control unit 120 executes the power saving transition control. This power saving transition control is a process executed in the vicinity of the timing T12 in FIG.

FIG. 9 is a diagram showing a flowchart of power saving transition control. In step S22, the second determination unit 128 determines whether or not the switching control has been stopped. As described above, the second determination unit 128 determines whether or not the switching control has been stopped based on the presence or absence of the detection signal from the FET 1142.

If NO is determined in step S22, that is, if the second determination unit 128 determines that the switching control of the FET 1142 has not been stopped, the process proceeds to step S24.

In step S24, the second adjusting unit 126 reduces the second voltage by one step. After that, the process returns to step S22. The processes of steps S22 and S24 are repeated until YES is determined in step S22, that is, until the second determination unit 128 determines that the switching control of the FET 1142 has been stopped. If YES is determined in step S22, the process proceeds to step S26.

In step S26, the control unit 120 outputs the switching stop voltage, which is the voltage at the time when YES is determined in S22, from the second output unit 114 as a new second voltage.

The explanation is returned to FIG. When the processing of S2 is completed, the process proceeds to S4. In S4, the control unit 120 executes the second output unit drive confirmation control. The second output unit drive confirmation control is the same as the process of FIG. The process of S4 is a process executed at a timing other than the timing for each resetting interval (timing T13, T14, T15, T16 ... In FIG. 7) during the power saving state.

In S6, the control unit 120 determines whether or not the resetting interval has elapsed. This process is, for example, a process of determining whether or not the timings T13, T14, T15, T16 ... Of FIG. 7 have been reached. If NO is determined in S6, that is, if it is determined that the timings T13, T14, T15, T16 ... In FIG. 7 have not been reached, the process returns to S4.

On the other hand, if YES is determined in S6, that is, if it is determined that the timings T13, T14, T15, T16 ... In FIG. 7 have been reached, the process proceeds to step S8.

In step S8, the first adjusting unit 122 increases the second voltage by one step. After that, in step S10, the first determination unit 124 determines whether or not the switching control of the FET 1142 is stopped. If YES is determined in step S10, the process returns to step S8. If NO is determined in step S10, the process proceeds to step S12.

In step S12, the first adjusting unit 122 further reduces the second voltage by one step. In step S14, the control unit 120 outputs the switching stop voltage, which is the voltage reduced by one step in S12, from the second output unit 114 as a new second voltage.

Further, in FIG. 7, a plurality of vertical lines are described at the timings T13, T14, T15, T16 ... When the reset interval is reached (switching control is executed a plurality of times). This is based on the fact that the second voltage is intentionally increased until the switching control is executed (until it is determined to be NO in S10), as described in S8 to S12.

In step S14, the control unit 120 determines whether or not the power saving state is in effect. If it is determined in step S14 that the power saving state has not ended, the process returns to step S6. As a modification, if it is determined that the power saving state has not ended, the process may return to step S4. If it is determined in step S14 that the power saving state has ended, the power saving state control of FIG. 8 ends.

Further, the voltage output from the second output unit 114 during the power saving state may be referred to as a "third voltage".

[Effects of the image forming apparatus of this embodiment]
The effects of the image forming apparatus 100 of the present embodiment will be described below.

(1) The image forming apparatus 100 of the present embodiment adjusts the second voltage so that the second voltage is output as the switching stop voltage (maximum voltage) when controlled to the power saving state. The switching stop voltage is a voltage at which the switching control of the FET 1142 is stopped. In other words, the second voltage in the power saving state can be said to be the voltage immediately before the switching control is executed. Therefore, the image forming apparatus 100 can make the second voltage output from the second output unit 114 substantially the same in the operating state, the standby state, and the power saving state. In other words, the image forming apparatus 100 can make the second voltage and the third voltage substantially the same.

Therefore, the image forming apparatus 100 has the first effect that the efficiency of the power saving state can be improved. Further, the switching stop voltage is also a voltage that does not fall below the lower limit value (4.85V) of the voltage output from the second output unit 114. Therefore, it is possible to reduce the possibility that the control component corresponding to the second output unit 114 malfunctions and the system operation is stopped or the component is damaged, which is the second effect.

Further, in order to add a means for exerting the first effect and the second effect to the conventional image forming apparatus, for example, as a component related to voltage setting (feedback control), high accuracy and high accuracy. It is necessary to use parts with good temperature characteristics. Further, the producer of the image forming apparatus needs an adjustment process on the production line. Then, the manufacturing cost of the image forming apparatus increases.

However, in the image forming apparatus of the present embodiment, it is not necessary to use parts having high accuracy and good temperature characteristics, and the producer of the image forming apparatus does not need an adjustment step on the production line. Therefore, it is possible to prevent the manufacturing cost of the image forming apparatus from increasing.

(2) Further, in the vicinity of the timing T12 of FIG. 7, the process of S2 of FIG. 8 is executed. Therefore, the image forming apparatus 100 exerts the first effect and the second effect even in the vicinity of the start timing of the control to the power saving state.

(3) Further, the process of step S4 in FIG. 8 is executed at a timing other than the timing for each resetting interval (timing T13, T14, T15, T16 ... In FIG. 7). Therefore, the image forming apparatus 100 can stop the switching control even if the switching control by the FET 1142 is suddenly executed in the power saving state. Therefore, the image forming apparatus 100 has the first effect.

(4) At the timing for each resetting interval (timing T13, T14, T15, T16 ... In FIG. 7), the control unit 120 executes the processes of steps S8 to S16 in FIG. Therefore, the switching stop voltage is newly set at the timing of each resetting interval. For example, in the power saving state, the voltage at which the switching control by the FET 1142 is executed may fluctuate due to the temperature fluctuation of the component related to the voltage setting. Even in this case, since the switching stop voltage is newly set at the timing of each resetting interval, it is difficult to execute the switching control by the FET 1142 at a timing other than the timing of each resetting interval.

(5) Both the process of increasing the second voltage by one step and the process of increasing the second voltage by one step are executed by using the PWM signal. Therefore, the image forming apparatus 100 can appropriately execute the process of increasing the second voltage by one step and the process of increasing the second voltage by one step. The process of increasing the second voltage by one step and the process of increasing the second voltage by one step are executed, for example, by changing the duty ratio in the PWM signal.

As a modification, the image forming apparatus may use an analog signal for both the process of increasing the second voltage by one step and the process of increasing the second voltage by one step. Here, the analog signal is, for example, a signal whose voltage can be specified. By receiving the analog signal, the feedback unit 1130 identifies the voltage indicated by the analog signal. The feedback unit 1130 outputs the specified voltage from the first output unit 112. That is, when the second voltage is increased by one step, the control unit 120 transmits an analog signal indicating the voltage value of the second voltage increased by one step to the feedback unit 1130. By receiving the analog signal, the feedback unit 1130 outputs the "second voltage increased by one step" indicated by the analog signal from the first output unit 112. As a result, the image forming apparatus 100 can appropriately execute the process of increasing the second voltage by one step.

Further, when the second voltage is reduced by one step, the control unit 120 transmits an analog signal indicating the voltage value of the second voltage reduced by one step to the feedback unit 1130. By receiving the analog signal, the feedback unit 1130 outputs the "second voltage reduced by one step" indicated by the analog signal from the first output unit 112. Thereby, the image forming apparatus 100 can appropriately execute the process of reducing the second voltage by one step.

(6) The determination by the control unit 120 whether or not the FET 1142 is executing the switching control is executed based on the detection signal transmitted from the FET 1142. Therefore, as compared with the configuration in which a member different from the FET 1142 transmits a detection signal to the control unit 120, the image forming apparatus 100 of the present embodiment does not need to include the other member, and therefore has a number of parts. Can be reduced.

[Second Embodiment]
Next, the second embodiment will be described. The image forming apparatus of the first embodiment has been described as controlling the processing of S2 (that is, the processing of FIG. 9) to a power saving state. In the image forming apparatus of the second embodiment, for example, the process of FIG. 9 is executed before the image forming apparatus is shipped from the factory to the market, and the switching stop voltage is determined in advance. When determining the switching stop voltage, for example, the mode of the image forming apparatus is controlled to the detection mode (detection state) and then executed. The image forming apparatus of the present embodiment shifts to the detection mode when the transition operation for shifting to the detection mode is executed for the operation unit 50 by the operation unit 50.

FIG. 10 shows a flowchart in the detection mode. Since steps S22 to S26 in FIG. 10 are the same as steps S22 to S26 in FIG. 9, the description will not be repeated. In FIG. 10, after the end of step S26, the process proceeds to step S28.

In step S28, the image forming apparatus stores the value of the switching stop voltage determined in step S26 in the non-volatile memory. The non-volatile memory is, for example, ROM 102. In step S2 of the power saving state, the image forming apparatus reduces the second voltage from 24V to the value of the switching stop voltage stored in the ROM 102.

According to the image forming apparatus of the second embodiment, it is not necessary to execute step S2 of FIG. Therefore, the processing amount of the power saving state control in FIG. 8 can be reduced.

Further, the process of FIG. 10 may be executed even after the image forming apparatus is shipped to the market. For example, it is assumed that a serviceman of the image forming apparatus replaces a part of the image forming apparatus due to a failure of the image forming apparatus. In this case, the characteristics related to the switching stop voltage may change. In this case, the serviceman shifts to the detection mode and causes the image forming apparatus to execute the process of FIG. 10 to determine the switching stop voltage again. Therefore, even if the characteristics related to the switching stop voltage change, the value of the switching stop voltage can be appropriately determined.

[Third Embodiment]
Next, the third embodiment will be described. In the above-described embodiment, the resetting interval (see, for example, S6 in FIG. 8) has been described as being constant. In the third embodiment, an example will be described in which the image forming apparatus 100 has the function of the interval changing unit 134 for changing the resetting interval (predetermined period) according to a predetermined factor. In the third embodiment, the predetermined factor includes the temperature in the image forming apparatus 100. In this embodiment, a temperature sensor (not shown) is installed in the image forming apparatus. The control unit 120 has a function of a temperature detection unit 132 that detects the temperature in the image forming apparatus. The temperature detection unit 132 can detect the temperature inside the image forming apparatus by the detection signal from the temperature sensor.

FIG. 11 is a diagram showing the relationship between the temperature in the image forming apparatus and the resetting interval. FIG. 11A shows a state of the image forming apparatus 100 and the like. FIG. 11B shows the temperature (temperature change) in the image forming apparatus 100. FIG. 11C shows the resetting interval changed by the interval changing unit 134.

As shown in FIG. 11, the interval changing unit 134 of the third embodiment shortens the resetting interval as the temperature inside the image forming apparatus 100 increases. This is based on the phenomenon that the higher the temperature in the image forming apparatus 100, the higher the temperature of the parts related to the voltage setting (voltage stabilization) and the unstable switching stop voltage (more likely to fluctuate).

Therefore, the interval changing unit 134 of the present embodiment shortens the processing interval (that is, the resetting interval) for detecting the switching stop voltage as the temperature in the image forming apparatus increases. That is, when the temperature inside the image forming apparatus 100 is high, in other words, when the switching stop voltage is likely to fluctuate, the control unit 120 frequently performs a process of detecting the switching stop voltage. As a result, the image forming apparatus 100 can follow the switching stop voltage that tends to fluctuate.

In the example of FIG. 11, in the period of timing T31 to T32, that is, in the transition period from the standby state to the power saving state, the temperature (35 ° C. to 37 ° C.) in the image forming apparatus 100 is compared with other periods. Is relatively high. Therefore, the interval changing unit 134 sets the resetting interval to 1 ms, which is a short interval, during the period from timing T31 to T32.

Immediately after being controlled to the power saving state, that is, the period from timing T32 to T33 is a period in which the temperature in the image forming apparatus is lower than the period from timing T31 to T32. Therefore, the interval changing unit 134 sets the reset interval to 10 ms, which is longer than 1 ms, in the period from timing T32 to T33.

The period from timing T33 to T34, that is, the period controlled to the power saving state is a period in which the temperature in the image forming apparatus 100 is lower than the temperature in the period from timing T31 to T33. Therefore, the interval changing unit 134 sets the reset interval to 1000 ms, which is longer than 10 ms, during the period from timing T33 to T34 (during the power saving state).

Further, in the period from timing T34 to T35, that is, in the transition period from the power saving state to the standby state, the temperature inside the image forming apparatus 100 becomes high. Therefore, the interval changing unit 134 sets the reset interval to 1 ms during the period from timing T34 to T35 (during the standby state).

According to the image forming apparatus of the present embodiment, the interval changing unit 134 sets the resetting interval to a short interval during the period when the temperature inside the image forming apparatus 100 is high, that is, during the period when the switching stop voltage is liable to fluctuate. do. Therefore, the image forming apparatus 100 can follow the switching stop voltage that is likely to fluctuate even during the period in which the switching stop voltage is likely to fluctuate. Therefore, the image forming apparatus 100 can appropriately detect the switching stop voltage. On the other hand, if the temperature in the image forming apparatus 100 is low, that is, the fluctuation of the switching stop voltage is low as compared with the period in which the temperature in the image forming apparatus 100 is high, the interval changing unit 134 is reset. Set the interval to a long interval. Therefore, the image forming apparatus 100 can reduce the frequency of the process of detecting the switching stop voltage. Therefore, the image forming apparatus 100 can reduce the burden of the process of detecting the switching stop voltage.

[Fourth Embodiment]
Next, the fourth embodiment will be described. In the fourth embodiment, for example, the control system load may be driven during the power saving state. During the power saving state, for example, the operation unit 50 may be driven as a control system load, or a USB memory (not particularly shown) connected to the image forming apparatus 100 may be driven. For example, the operation unit 50 is driven to determine whether or not an operation from the user exists for the operation unit 50 during the power saving state. Further, for example, the USB memory is driven in order to determine whether or not the USB memory is properly connected during the power state.

Further, when these loads are driven during the power saving state, a current is output as a drive signal. This current may be output by the second output unit 114. Further, this current may be output from another location, for example, the control unit 120. Further, it is assumed that the control unit 120 (interval changing unit 134) of the image forming apparatus recognizes the timing at which the current is output to the load during the power saving state.

Further, in the present embodiment, when the current is output to the load, the interval changing unit 134 sets the reset period short. This is based on the fact that the switching stop voltage tends to fluctuate when the current is output to the load (when the current value output to the load fluctuates), that is, when the load fluctuates. Further, in the present embodiment, the above-mentioned predetermined factors include the start of the load drive and the end of the load drive.

FIG. 12 is a diagram showing the relationship between the current value output to the load and the resetting interval. FIG. 12A shows a state of the image forming apparatus 100 and the like. FIG. 12B shows a driving state of “load A” as a load for the operation unit 50. FIG. 12C shows a driving state of “load B” as a load for the USB memory. FIG. 12D shows the current values of the currents output to the load A and the load B. FIG. 12E shows the resetting interval changed by the interval changing unit 134. As shown in FIG. 12, during the power saving state, a predetermined amount of current (0.2 A in the example of FIG. 12) is applied to the control system load even when neither the load A nor the load B is driven. Is output.

During the transition period from timing T41 to T42, the interval changing unit 134 sets the reset interval to 1 ms. From the timing T42 when the control to the power saving state is started, the interval changing unit 134 sets the reset interval to 1000 ms. Further, the interval changing unit 134 sets the reset interval to 10 ms at the timing T43 before the specific period before the timing T44 for driving the load A (current is output to the load A). do. This specific period is a predetermined period.

At the subsequent timing T44, the load A is driven by the control unit 120. From the timing T44 to the timing 45 when the specific period has elapsed, the interval changing unit 134 maintains 10 ms as the resetting interval. In the timings T45 to T46 during which the load A is driven, the interval changing unit 134 sets the reset interval to 1000 ms. During the period in which the load A is driven, the output current value is constant, so that the switching stop voltage does not fluctuate much. Therefore, in the period from timing T45 to T46, the interval changing unit 134 is set to a longer reset interval.

After that, at the timing T46 before the specific period before the timing T47 for stopping the drive to the load A (stopping the output of the current to the load A), the interval changing unit 134 sets the reset interval to 10 ms. ..

After that, at the timing T47, the control unit 120 stops driving to the load A. From the timing T47 to the timing T48 when a specific period elapses, the interval changing unit 134 maintains 10 ms as the resetting interval. The interval changing unit 134 sets the resetting interval to 1000 ms at the timing T48.

After that, at the timing T49 before the specific period before the timing T50 in which the control unit 120 drives the load B (current is output to the load B), the interval changing unit 134 sets the reset interval to 100 ms. ..

At the subsequent timing T50, the load B is driven by the control unit 120. From the timing T50 to the timing 51 when the specific period has elapsed, the interval changing unit 134 maintains 100 ms as the reset interval. In the timings T51 to T52 during which the load B is driven, the interval changing unit 134 sets the reset interval to 1000 ms. During the period in which the load B is driven, the output current value is constant, so that the switching stop voltage does not fluctuate much. Therefore, in the period from timing T51 to T52, the interval changing unit 134 is set to a longer interval.

After that, at the timing T52 before the specific period before the timing T53 for stopping the drive to the load B (stopping the output of the current to the load B), the interval changing unit 134 sets the reset interval to 100 ms. ..

After that, at the timing T53, the control unit 120 stops driving to the load B. From the timing T53 to the timing T54 when a predetermined time elapses, the interval changing unit 134 maintains 100 ms as the resetting interval. The interval changing unit 134 sets the resetting interval to 1000 ms at the timing T54.

After that, the control unit 120 maintains the reset interval at 1000 ms until the timing T55 when the transition period starts. From the timing T55 when the transition period starts, the interval changing unit 134 sets the reset interval to 1 ms. After that, the control unit 120 maintains 1 ms as the reset interval until the timing T56 when the standby state is started.

As described above, the interval changing unit 134 of the present embodiment shortens the resetting interval at the timing (for example, T43 and T49) before the specific period from the timing of driving the load in the power saving state. After that, the shortened reset interval is maintained from the timing of driving the load to the timing after a specific period (for example, T45 and T51).

In this way, in the period before and after the timing to drive the load (that is, the period from timing T43 to T45 and the period from timing T49 to T51), the current value output to the load fluctuates. be. This period is a period in which the switching stop voltage is likely to fluctuate.

Further, the interval changing unit 134 of the present embodiment shortens the resetting interval at a timing (for example, T46 and T52) before a specific period from the timing at which the load drive is stopped. After that, the shortened reset interval is maintained from the timing at which the load drive is stopped to the timing after a specific period (for example, T48 and T55).

In this way, the current value output to the load fluctuates in the period before and after the timing when the load drive is stopped (that is, the period from timing T46 to T48 and the period from timing T52 to T54). It is a period. This period is a period in which the switching stop voltage is likely to fluctuate.

In this way, the image forming apparatus sets the resetting interval to a short interval during the period in which the switching stop voltage is likely to fluctuate. Therefore, the image forming apparatus can follow the switching stop voltage that is likely to fluctuate even during the period in which the switching stop voltage is likely to fluctuate. Therefore, the image forming apparatus can appropriately detect the switching stop voltage.

Further, the interval changing unit 134 of the present embodiment sets the resetting interval according to the driven load, that is, according to the current value output to the driven load. In the present embodiment, the larger the current value output to the driven load, the shorter the resetting interval is set. In the example of FIG. 12, the interval changing unit 134 sets 10 ms as the reset interval for the load A driven by outputting a current of 0.8 A. Further, the interval changing unit 134 sets 100 ms as the reset interval for the load B driven by outputting the current of 0.6 A. In general, the larger the current value output to the driven load, the more frequently the switching stop voltage tends to fluctuate. That is, it can be said that the resetting interval is a period of the load A (first load) and the load B (second load) according to the load to which the current is output during the power saving state. Therefore, even if the current value output to the driven load increases and the frequency of fluctuations in the switching stop voltage increases, the switching stop voltage can be appropriately detected by shortening the reset interval.

It should be considered that each embodiment disclosed this time is exemplary in all respects and is not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. Further, the inventions described in the embodiments and the modifications thereof are intended to be carried out alone or in combination as much as possible.

100 Image forming device, 122 1st adjustment unit, 124 1st judgment unit, 126 2nd adjustment unit, 128 2nd judgment unit, 130 state control unit, 132 temperature detection unit, 134 interval change unit, 202 control system load, 204 Drivetrain load.

Claims (8)

The first output unit that outputs the first voltage and
A second output unit having a switch unit and performing switching control of the switch unit to output a second voltage from the first output unit and having a voltage smaller than the first voltage unit.
Equipped with a state control unit that controls the power saving state,
The second output unit is an image forming apparatus that outputs the maximum voltage among the voltages at which the switching control of the switch unit is stopped as the second voltage when controlled to the power saving state. A first adjusting unit that increases the second voltage by one step each time a predetermined period elapses during the power saving state.
A first determination unit for determining whether or not the switching control is stopped when the second voltage is increased by one step by the first adjustment unit is provided.
The first adjusting unit is
When the first determination unit determines that the switching control has been stopped, the second voltage is further increased by one step.
When the first determination unit determines that the switching control has not been stopped, the second voltage is further reduced by one step.
The image forming apparatus according to claim 1, wherein the second output unit outputs the second voltage reduced by one step by the first adjusting unit as a new second voltage. The image forming apparatus according to claim 2, further comprising a period changing unit for changing the predetermined period according to a predetermined factor. The image forming apparatus according to claim 3, wherein the predetermined factor includes a temperature inside the image forming apparatus. During the power saving state, the second output unit drives a load.
The image forming apparatus according to claim 3 or 4, wherein the predetermined factor includes the start of driving the load and the end of driving the load. A second determination unit that determines whether or not the switching control is stopped, and
A second adjusting unit for reducing the second voltage by one step when the second determining unit determines that the switching control has not been stopped is provided.
The second adjusting unit reduces the second voltage output from the second output unit by one step until the second determining unit determines that the switching control has been stopped. ,
Claims 1 to 5 that the second output unit outputs the second voltage when the second determination unit determines that the switching control of the switch unit has been stopped as a new second voltage. The image forming apparatus according to any one of the following items. The state control unit controls the detection state to detect the maximum voltage, and controls the state.
The image forming apparatus according to claim 6, wherein the processing of the second adjusting unit and the processing of the second determining unit are executed during the detection state. The image forming apparatus according to claim 6 or 7, wherein the processing of the second adjusting unit and the processing of the second determination unit are executed when the power saving state is controlled.

Images