JP2018007319A - Image forming apparatus, power supply method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss inside an inverter device.SOLUTION: An image forming apparatus 1 comprises: a chargeable/dischargeable DC power supply battery 16 that is charged by a power supplied from a commercial power supply 11; an inverter device 17 that converts the power from the DC power supply batter into an AC power and outputs the AC power; a power supply device 22 that supplies the power supplied from the commercial power supply 11 or the power output from the inverter device 17 to loads 24 and a fixing heater 30; and a switching device 14 that switches a power supplied to the power supply device 22 to either one of the power supplied from the commercial power supply 11 or the power output from the inverter device 17. The inverter device 17 includes a plurality of capacitors (1)20a and (2)20b having different sizes of capacity components, and a switching circuit 20c that switches to either one of the plurality of capacitors (1)20a and (2)20b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, a power supply method, and a program.

  When a large-scale blackout occurs due to an earthquake disaster or the like, an image forming apparatus such as a digital multi-function peripheral (MFP) cannot be used. Thus, the need for a digital multifunction machine equipped with a storage battery that assumes a large-scale power outage has increased, and the need for a storage battery system compatible with an image forming apparatus equipped with a halogen heater has attracted attention. For example, a technique described in Japanese Patent Application Laid-Open No. 2001-253152 is known as a technique in which a storage battery system is mounted.

  This technology is designed to prevent a halogen heater from being turned off and execute a print command when power is supplied from the uninterruptible power supply in a multi-function machine having a thermal fixing printer function connected to the uninterruptible power supply. It is a feature. In this technology, when the multifunction device communicates with the storage battery and the multifunction device receives power supply from the power storage device, the multifunction device prohibits output processing such as a print mode that consumes a large amount of power. The purpose is to reduce and lengthen the retention time of the storage battery.

  However, in an image forming apparatus equipped with a halogen heater as a fixing heater as in the prior art, a large current flows when the halogen heater is turned on or at the start of printing. Therefore, an AC output inverter device built in the power storage system The output circuit required a large capacity capacitor. For this reason, a reactive current is generated by the output side capacitor, and there is a problem that a large power loss is always caused inside the power storage system.

  Therefore, the problem to be solved by the present invention is to reduce the power loss inside the inverter device.

  In order to solve the above-described problems, an embodiment of the present invention includes a chargeable / dischargeable battery that is charged by power supplied from the outside, an inverter device that converts the power of the battery into AC power, and outputs the power from the outside. A power supply device that supplies the supplied power or the power output from the inverter device to each load and the fixing heater, and the power supplied to the power supply device from the outside or the power output from the inverter device An image forming apparatus comprising: a first switching unit configured to switch to any one of a plurality of capacitors having different capacitance components; and a second switching unit configured to switch to one of the plurality of capacitors. It is characterized by including these.

  According to one embodiment of the present invention, power loss inside the inverter device can be reduced. Note that problems, configurations, and effects other than those described above will be clarified in the following description of embodiments.

1 is a block diagram showing a schematic configuration of an image forming apparatus according to Example 1 in an embodiment of the present invention. It is a block diagram which shows the structure of the conventional image forming apparatus incorporating the electrical storage apparatus. It is a figure which shows the relationship between the operation mode of a prior art, power consumption, and the capacitor | condenser used. It is a figure which shows the relationship between the operation mode of Example 1, power consumption, and the capacitor | condenser used. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment. FIG. 3 is a diagram illustrating an operation sequence of the image forming apparatus main body and the power storage device in Embodiment 1. 6 is a block diagram illustrating a configuration of an image forming apparatus according to a modified example 1-1 of Embodiment 1. FIG. 10 is a diagram illustrating an operation sequence of an image forming apparatus main body and a power storage device in Modification 1-1. FIG. 10 is a block diagram illustrating an internal configuration of a control unit of an image forming apparatus main body according to Modification 1-1. It is a figure which shows the sequence of the capacitor | condenser switching signal and operation mode in the modification 1-1. It is a figure shown about the operation mode in modified example 1-1, power consumption, and the capacitor | condenser used. 6 is a block diagram illustrating a configuration of an image forming apparatus according to Modification 1-2 of Example 1. FIG. It is a figure which shows the sequence of the capacitor | condenser switching signal and operation mode in the modification 1-2. It is a figure shown about the operation mode in modified example 1-2, power consumption, and the capacitor | condenser used. 6 is a block diagram illustrating a configuration of an image forming apparatus according to Modification 1-3 of Embodiment 1. FIG. It is a figure which shows the sequence of the energy-saving control signal and switching circuit in the modification 1-3. It is a figure shown about the operation mode in modified example 1-3, power consumption, and the capacitor | condenser used. 6 is a circuit diagram illustrating a configuration of a switching circuit according to Modification 1-4 of Example 1. FIG. It is a block diagram which shows schematic structure of the image forming apparatus which concerns on Example 2 in embodiment of this invention. It is a figure which shows the difference of the reactive current by the capacity | capacitance of the output capacitor | condenser in FIG. FIG. 9 is a diagram illustrating an AC output voltage waveform output from an inverter circuit input to the image forming apparatus main body according to the second embodiment. It is a figure which shows the influence on the zero cross detection by the magnitude | size of the output voltage distortion in Example 2. FIG. It is the figure which showed the timing which changes the switching frequency of the inverter circuit in FIG. It is a flowchart which shows the process sequence at the time of changing the switching frequency of the inverter circuit in FIG. It is a figure which shows schematic structure of the image forming apparatus which concerns on Example 3 in embodiment of this invention. It is a figure which shows the production | generation method of the inverter output waveform in Example 3. FIG. It is a figure which shows the inverter output waveform at the time of switching an output capacitor in Example 3. FIG. It is an enlarged view of the inverter output waveform shown in FIG. It is a flowchart which shows the process sequence of Example 3 which selects the capacity | capacitance of an output capacitor by the determination result of a zero cross necessity / unnecessity determination part. FIG. 10 is a diagram illustrating a schematic configuration of an image forming apparatus according to a modified example 3-1 of the third embodiment. It is a flowchart which shows the process sequence of the modification 3-1. FIG. 10 is a diagram illustrating a schematic configuration of an image forming apparatus according to a modification 3-2 of the third embodiment. It is a flowchart which shows the process sequence of modification 3-2. FIG. 10 is a diagram illustrating a schematic configuration of an image forming apparatus according to Modification 3-3 of Embodiment 3. It is a flowchart which shows the process sequence of the modification 3-3. FIG. 10 is a diagram illustrating a schematic configuration of an image forming apparatus according to a modified example 3-4 of the third embodiment. It is a flowchart which shows the process sequence of the modification 3-4.

  The present invention includes a switching means for switching between two or more types of capacitors instead of one type, and switches on a capacitor having a large capacity in an operation mode of an image forming apparatus in which a large current flows, which turns on a halogen heater as a fixing heater. In the image forming apparatus operation mode in which the halogen heater is not turned on, the capacitor is switched to a capacitor having a small capacity. As described above, when the halogen heater is not lit, the output capacitor is switched to one having a smaller capacity, thereby reducing useless power loss. As a result, it is possible to improve the energy saving performance of the power storage device including the inverter device, and thus the image forming apparatus. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a block diagram showing a configuration of a conventional image forming apparatus incorporating a power storage device (including an inverter device).

  In FIG. 1, the image forming apparatus 1 includes a power storage device 12 and an image forming apparatus main body 13. In the figure, the power storage device 12 and the image forming apparatus main body 13 are illustrated as separate bodies, but the power storage device 12 is built in the image forming apparatus main body 13. The power storage device 12 basically includes a switching device 14, a charger 15, a DC power supply battery 16, an inverter device 17, and a power failure detection circuit 28. The power storage device 12 is supplied with AC power from the commercial power supply 11, AC power is supplied as it is to the image forming apparatus main body 13 when there is no power failure, and the inverter device 17 AC converts the charge stored in the DC power supply battery 16 during power failure. AC power is supplied to the image forming apparatus main body 13. Power failure and non-power failure are detected by the power failure detection circuit 28 in the power storage device 12.

  The power failure detection circuit 28 monitors the alternating current waveform of the commercial power supply 11. When the alternating current waveform stops, the power failure detection circuit 28 determines that a power failure occurs and outputs a power failure signal to the power failure detection signal line 26. If a power failure is detected, a power failure signal is sent to the switching device 14 via the power failure detection signal line 26. The switching device 14 receives the power failure signal, and switches from the commercial power supply 11 to the supply from the AC power source obtained by AC conversion of the charge stored in the DC power supply battery 16. The DC power supply battery 16 in the power storage device 12 is charged by the charger 15.

  The inverter device 17 receives, for example, DC 48 V from the DC power supply battery 16, boosts it to DC 200 V by the DC booster 18, converts it to a sine wave AC 100 V by the inverter circuit 19 and the smoothing filter circuit 29, and outputs it. In addition, an output capacitor 20 is provided to stabilize the output voltage.

  The image forming apparatus main body 13 includes a power supply device 22. The AC / DC conversion unit 33 generates a DC power supply from the AC power supply, and supplies the AC power supply to the fixing heater 30. The fixing heater 30 is controlled by a heater control signal 32 from the control unit 25 of the image forming apparatus main body 13 and is turned on / off using a triac 31. A load 24 indicates a load in the image forming apparatus main body 13, and power is supplied from the power supply device 22. The control unit 25 of the image forming apparatus main body 13 controls the image forming apparatus main body 13 and grasps the operation state of the image forming apparatus main body 13. In addition, it communicates with the power storage device 12.

  A large capacitor 23 is provided on the input side of the power supply device 22, and the output of the power supply device 22 can be maintained even when the power supply to the image forming apparatus main body 13 is temporarily cut off by the stored charge. When there is no power failure, the image forming apparatus main body 13 is supplied from the commercial power supply 11, but in preparation for a power failure, the inverter device 17 is operating and reactive power is generated in the output capacitor 20. Extra power from the commercial power supply 11 to the power storage device 12 increases.

  FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus 1 according to the first embodiment of the invention. 2 is different from the conventional example shown in FIG. 2 only in a part of the inside of the power storage device 12, and a configuration different from the conventional example will be described.

  The first embodiment focuses on the fact that the capacity of the capacitor may be small in the operation mode in which power is not supplied from the power storage device 12 during a non-power failure. Therefore, two or more types of capacitors are provided instead of one type, and the type of the capacitor is switched. When there is no power failure, output is performed with the smaller capacitor capacity, and when power supply is required from the power storage device 12 to the image forming apparatus main body 13 when a power failure occurs, the output is switched to the larger capacitor capacity. Thus, in Example 1, the power loss of each part of a coil, a drive circuit, and a capacitor | condenser can be suppressed by changing the capacitor | condenser capacity | capacitance used according to the operation mode of non-power failure / power failure.

  Therefore, the output capacitor 20 in the first embodiment includes two types of capacitors, a small-capacitance capacitor (1) 20a and a large-capacitance capacitor (2) 20b, and further includes a switching circuit 20c that switches between the two types of capacitors. . Other configurations are the same as those of the conventional example shown in FIG.

  3A and 3B are diagrams showing the relationship between the conventional technology and the operation mode, power consumption, and capacitors used in the image forming apparatus 1 according to the first embodiment. FIG. 3A (a) shows a state during a non-power failure in the prior art, FIG. 3 (b) shows a state during a power outage according to the prior art, FIG. 3B (c) shows a state during a non-power outage in Example 1, and FIG. b) shows the state at the time of a power failure in Example 1, respectively. The operation modes are divided into power-off and power-on. When the power is turned on, warm-up, standby, printing, automatic document reading, standby, and energy saving modes are set. From the figure, it can be seen that power consumption increases during warm-up, printing, and automatic document reading.

  In the prior art, as can be seen from FIGS. 3A (a) and 3 (b), there is one type of capacitor to be used regardless of the operation mode of the image forming apparatus 1, and therefore the inside of the power storage device 12 (inside the inverter device 17) even during a non-power failure. ) Large power loss is always constant. On the other hand, in the first embodiment, as shown in FIG. 3B (c), in the operation mode in which power is not supplied from the power storage device 12 during a non-power failure, the output capacitor 20 is switched by the switching circuit 20c so that the small-capacitance capacitor (1). It can be seen that the internal loss corresponding to the reactive current of the inverter device 17 is suppressed. It can be seen that the power loss is very low when switched to the small capacitor (1) 20a.

  On the other hand, when a power failure occurs, the output capacitor 20 is switched to a large-capacitance capacitor (2) 20b in an operation mode in which power supply from the power storage device 12 to the image forming apparatus main body 13 is required. Therefore, the image forming apparatus main body 13 can be operated with the same power loss as before. In this way, by switching the capacity of the output capacitor 20 by the switching circuit 20c in accordance with the non-power failure / power failure operation mode, the type of capacitor to be used can be optimized, and the total power loss can be reduced.

  FIG. 4 is a diagram illustrating a schematic configuration of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 is a digital multi-function peripheral (MFP), and generally includes an automatic document feeder (ADF) 2, an image reading device 3, a writing unit 4, and a printer unit 5. The printer unit 5 further includes a photosensitive drum 6, a developing device 7, a conveyance belt 8, a fixing device 9, and the like.

  The digital multi-function peripheral as in the present embodiment has a copy function, a printer function, a facsimile function, and the like, and the copy function, the printer function, and the facsimile function can be sequentially switched and selected by an application switching key of the operation unit. It has become. The copy mode is selected when the copy function is selected, the printer mode is selected when the printer function is selected, and the facsimile mode is selected when the facsimile mode is selected.

  In the copy mode, the document bundle is sequentially fed to the image reading device 3 by the automatic document feeder 2, and the image information of the document is read by the image reading device 3. The read image information is converted into optical information by the writing unit 4 as writing means through the image processing means. The photosensitive drum 6 is uniformly charged by a charger (not shown) and then exposed with optical information from the writing unit 4, and an electrostatic latent image is formed on the surface of the photosensitive drum 6. The electrostatic latent image on the photosensitive drum 6 is developed by the developing device 7 to become a toner image. This toner image is transferred onto a transfer sheet by the conveyance belt 8, and the transfer sheet is discharged with the toner image fixed by a fixing device 9.

  In the description with reference to FIGS. 1 to 4, the outline of the configuration and operation of the image forming apparatus 1 according to the present embodiment has been described. This will be described in more detail below.

  FIG. 5 is a diagram illustrating an operation sequence of the image forming apparatus main body 13 and the power storage device 12 according to the first embodiment. The power failure or non-power failure shown in FIG. 4 is detected by the power failure detection circuit 28 in the power storage device 12. The power failure detection circuit 28 monitors the alternating current waveform of the commercial power supply 11. When the alternating current waveform stops, the power failure detection circuit 28 determines that a power failure occurs and outputs a power failure signal to the power failure detection signal line 26. The time from when the AC waveform stops to when a power failure is determined is about 5 ms. This numerical value is an example, and the detection time can be shortened when a high-performance circuit is used, and the detection takes a long time when an inexpensive circuit is used.

  If a power failure is detected, the switching device 14 switches from the power supply of the commercial power supply 11 to the AC power supply from the inverter device 17 that has AC-converted the charge stored in the DC power supply battery 16 via the power failure detection signal line 26. It takes about 15 ms until the switching device 14 receives the power failure signal and switches to the power output from the inverter device 17 of the power storage device 12. This 15 ms is the operation time of the switching device 14. At the same time, the switching circuit 20c of the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b. This also takes about 15ms. This 15 ms is the operation time of the switching circuit 20c. Here, 15 ms is an indefinite period.

  As can be seen from FIG. 5, it takes about 20 ms for the commercial power supply 11 to switch to the output from the power storage device 12 after a power failure. FIG. 5 shows an operation sequence of the commercial power supply 11, the output of the power failure detection circuit 28, the output of the switching device 14, and the input voltage of the power supply device 22. The indefinite periods 15 ms and 20 ms are also examples. As described above, when high-performance components and circuits are used, the time can be shortened, and when inexpensive circuits are used, switching takes a long time. Further, the indefinite period 20 ms is conceived to be a value obtained by adding the indefinite period 15 ms to 5 ms, which is the time from when the AC waveform stops until the power failure is determined.

  As shown in FIG. 3, the capacitor used at the time of non-power failure is a small-capacitance capacitor (1) 20a. Therefore, the power loss inside the power storage device 12 (inside the inverter device 17) is small at the time of non-power failure. Therefore, there is an effect of reducing power consumption at the time of non-power failure. Note that, when a power failure occurs, the capacitor (2) 20b is switched to a large-capacity capacitor (2) 20b with a large power loss. This is to stabilize the output voltage of the power storage device 12 even when a large amount of power is supplied, such as the printing mode of the image forming apparatus 1. It is.

  In addition, Example 1 demonstrated so far is related with the technique which reduces the power consumption at the time of a non-power failure, and is not considered to reduce the power loss in the electrical storage apparatus 12 at the time of a power failure. However, if the power loss at the time of a power failure is not reduced, consumption of the DC power supply battery 16 in the power storage device 12 is accelerated. Therefore, a configuration for extending the battery life during a power failure will be described as a first modification of the first embodiment.

[Modification 1-1]
FIG. 6 is a block diagram illustrating a configuration of the image forming apparatus 1 according to the modified example 1-1 of the first embodiment.

  In the first modification, an AND element 20d is arranged in front of the switching circuit 20c of the output capacitor 20 with respect to the first embodiment shown in FIG. 2, and the power failure signal of the power failure detection circuit 28 and the image forming apparatus main body are arranged in the AND element 20d. The control signal of 13 control units 25 is input, and either a High or Low signal is output from the AND element 20d to the switching circuit 20c. The other parts are the same as those in FIG.

  FIG. 7 is a diagram illustrating an operation sequence of the image forming apparatus main body 13 and the power storage device 12 in Modification 1-1. FIG. 7 shows a specific operation sequence in the commercial power supply 11, the output of the power failure detection circuit 28, the output of the control signal from the control unit 25, the state of the switching device 14, the state of the switching circuit 20c, and the input voltage of the power supply device 22. Is shown.

  As shown in FIG. 6, a power failure or non-power failure is detected by a power failure detection circuit 28 in the power storage device 12. The power failure detection circuit 28 monitors the alternating current waveform of the commercial power supply 11. When the alternating current waveform stops, the power failure detection circuit 28 determines that a power failure occurs and outputs a power failure signal to the power failure detection signal line 26. When a power failure is detected, the switching device 14 switches to the supply from the AC power source obtained by AC conversion of the charge stored in the DC power battery 16 from the commercial power source 11 via the power failure detection signal line 26. It takes about 15 ms for the switching device 14 to switch to the power storage device 12 after receiving the power failure signal. This 15 ms is the operation time of the switching device 14.

  Further, when the control signal of the control unit 25 also issues an instruction signal for selecting the large-capacitance capacitor (2) 20b, a high signal is output by the AND element 20d in the previous stage of the switching circuit 20c, and the switching circuit of the output capacitor 20 20c is switched to the large capacity capacitor (2) 20b side. It takes about 15 ms until the switching circuit 20c is switched. This 15 ms is the operation time of the switching circuit 20c. In the figure, 15 ms is expressed as an indefinite period. The indefinite periods 15 ms and 20 ms shown in FIG. 7 are also examples, and the time can be shortened when high-performance components and circuits are used, and switching takes a long time when inexpensive circuits are used.

  FIG. 8 is a block diagram illustrating an internal configuration of the control unit 25 of the image forming apparatus main body 13. In the figure, the control unit 25 includes a CPU 50, a memory 51, and a driver 52. The CPU 50 controls the image forming apparatus 1. The memory 51 includes ROM (Read Only Memory), RAM (Random Access Memory), NVRAM (Non Volatile RAM), and the like. The ROM is a read-only memory in which a program and setting values for operating the image forming apparatus 1 are stored, and table data in which an operation state and power consumption are paired is also stored. Thus, the CPU 50 can determine the amount of power consumption for each operation state by referring to the data table every time the operation state changes. The RAM is a writable and readable memory used as a work memory for developing programs and data.

  The large-capacitance capacitor (2) 20b is used to output a stable output voltage from the power storage device 12 even in an operation mode with large power consumption. Therefore, the control unit 25 switches the switching circuit 20c 15 ms earlier before shifting to the operation mode with large power consumption, and outputs a stable output voltage from the power storage device 12 even in the operation mode with large power consumption. The driver 52 receives a command signal output from the CPU 50 and drives a motor, a sensor, and the like of the image forming apparatus 1.

  FIG. 9 is a diagram showing a sequence of the capacitor switching signal and the operation mode in Modification 1-1. FIG. 9 shows an operation mode (power consumption: small and large), output of a control signal from the control unit 25, and an operation sequence of the switching circuit 20c. FIG. 9 shows a state in which the control unit 25 predicts an increase in power consumption and switches to the large capacity capacitor (2) 20b before a large current is actually required. By predicting in this way and outputting the control signal for switching to the capacitor (2) 20b first so as to clear the indefinite period, the operation mode is in accordance with the timing w at which the power consumption: large state is reached. The output capacitor 20 can be switched to a large-capacitance capacitor (2) 20b.

  FIG. 10 is a diagram illustrating an operation mode, power consumption, and a capacitor to be used in Modification 1-1. FIG. 4A shows a state at the time of non-power failure, and FIG. 4B shows a state at the time of power failure.

  Before the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is in a power OFF state. At this time, as shown in FIG. 10A, the capacitor switching signal (control signal) of the control unit 25 (FIG. 6) selects the capacitor (1) 20a having a small capacity. From the sequence diagram of FIG. 7, it can be seen that the capacitor type used is the capacitor (1) 20a when the control signal is OFF, and the capacitor type used is the capacitor (2) 20b when the control signal is ON.

  Also in FIG. 10, as shown in FIG. 3 of the first embodiment, the operation mode is divided into power OFF and power ON, and when the power is ON, warm-up, standby, printing, automatic document reading, standby and Energy saving mode is set. When the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is turned on. When the power is turned on, warm-up that is an initialization process inside the image forming apparatus 1 that consumes a large amount of power starts. Therefore, the control unit 25 of the image forming apparatus 1 turns on the control signal in advance as shown in FIG. The capacitor type to be used is capacitor (2) 20b. In the warm-up, the rotation of each motor of the image forming apparatus 1 and the temperature raising process of the fixing halogen heater that serves to fix the toner image are performed. It usually ends in 2-5 minutes.

  After the control unit 25 of the image forming apparatus 1 determines that the warm-up is finished, the control signal is turned off and the capacitor type is switched to the capacitor (1) 20a. Thereafter, the use of the capacitor (1) is continued. This continuation of use is continued until the next sheet transport or document transport mode, ie, the printing mode or document reading mode, which is the next operation mode with the highest power consumption, and during that time, the capacitor (1) 20a is used. When the state in which sheet conveyance or document conveyance is performed starts, the control signal is turned on before the image forming apparatus 1 performs conveyance, and the capacitor type to be used is the capacitor (2) 20b. By using the capacitor (2) 20b as the capacitor type used in this way, the image forming apparatus 1 is provided with an operation mode that consumes a large current so that a stable output voltage can be supplied from the power storage device 12.

  If the capacitor (1) 20a has been selected because the switching to the capacitor (2) 20b has failed in the operation mode in which the power consumption of the image forming apparatus 1 is large, the necessary power is supplied to the image forming apparatus 1. The power of the image forming apparatus 1 may be cut off.

  As described above, in the first modification, the control unit 25 of the image forming apparatus 1 manages the operation mode and controls the control signal.

 Comparing FIGS. 10A and 10B with FIGS. 3A and 3B, it can be seen that the internal loss corresponding to the reactive current of the inverter device 17 is also suppressed in the modified example 1-1. It can be seen from the figure that the power loss is very low when switching to the small capacitor (1) 20a.

[Modification 1-2]
In the first modification, the control unit 25 of the image forming apparatus main body 13 needs to manage the operation mode and control the control signal. Therefore, in the modified example 1-2, the image forming apparatus 1 is configured to use the control signal existing in the past to reduce the loss in the inverter device 17. With the configuration of the modified example 2, the control unit (software unit) 25 of the image forming apparatus 1 is not complicated. However, the capacitor (1) 20a having the smaller capacity must have a capacity corresponding to the power consumption in the document reading mode. Compared with the first modification, the loss inside the inverter is higher when the document reading mode is used. Increases and the battery of the power storage device is quickly consumed.

  FIG. 11 is a block diagram illustrating a configuration of an image forming apparatus according to Modification 1-2 of Embodiment 1.

  The modified example 1-2 is an example in which the fixing relay 36 is disposed before the power supply circuit to the triac 31 of the image forming apparatus main body 13 of the modified example 1. A fixing relay control signal 36 a is input to the fixing relay 36 from the control unit 25, and the fixing relay 36 is controlled by the control unit 25.

  The fixing relay 36 is used as a protective component that serves to reliably cut off the energization of the fixing heater 30 when an abnormality occurs in the image forming apparatus 1. The fixing relay control signal 36a is connected to the AND element 20d in the previous stage of the switching circuit 20c in the output capacitor 20. With this configuration, the switching circuit 20c selects the large-capacitance capacitor (2) 20b at the time of a power failure and when the fixing relay is ON. Since each other part is comprised similarly to the modification 1, the overlapping description is abbreviate | omitted.

  FIG. 12 is a diagram showing a sequence of the capacitor switching signal and the operation mode in Modification 1-2. FIG. 12 shows an output signal (power failure signal) of the power failure detection circuit 28, a control signal output from the control unit 25 to the fixing relay 36, and an operation sequence of the switching circuit 22c.

  As shown in FIG. 12, the capacitor (1) 20a having a small capacity is selected even when the fixing relay 36 is ON during a non-power failure. On the other hand, the switching circuit 20c selects the capacitor (2) 20b having a large capacity when a power failure occurs and the fixing relay 36 is ON. As described above, an indefinite period occurs when switching to the capacitor (2) 20b.

  FIG. 13 is a diagram illustrating an operation mode, power consumption, and a capacitor to be used in Modification 1-2. FIG. 4A shows a state at the time of non-power failure, and FIG. 4B shows a state at the time of power failure. Also in FIG. 13, as shown in FIG. 3 of the first embodiment, the operation mode is divided into power OFF and power ON. When the power is ON, warm-up, standby, printing, automatic document reading, standby and Energy mode is set.

  Before the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is in a power OFF state. Since the fixing relay 36 is also OFF when the power is OFF, the switching circuit 20c at this time selects the capacitor (1) 20a. From FIG. 12, when the fixing relay control signal 36a is OFF, the power supply is in the OFF state, and therefore the capacitor type to be used is the capacitor (1) 20a. When the fixing relay control signal 36a is ON, the capacitor type to be used is the capacitor (2) 20b.

  When the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is turned on. When the power is turned on, warm-up (procedure control), which is an initialization process inside the image forming apparatus 1 with high power consumption, is started. At the time of warm-up, the fixing relay 36 is also turned on because the temperature increasing process of the fixing (halogen) heater 30 for fixing the toner image is also performed. Therefore, the capacitor type is switched to the capacitor (2) 20b.

  When the warm-up is completed and the operation mode shifts to a standby mode in which the fixing (halogen) heater 30 does not need to be turned on, the fixing relay 36 is turned OFF, and the capacitor type is switched to the capacitor (1) 20a. Next, when the printing mode is executed, since the fixing relay 36 is turned on before that, the capacitor type is switched to the capacitor (2) 20b, and the printing mode is an operation mode that consumes a large current of the image forming apparatus main body 13. Is provided so that a stable voltage can be supplied from the power storage device 12.

 Comparing FIGS. 13A and 13B with FIGS. 3A and 3B, it can be seen that the internal loss corresponding to the reactive current of the inverter device 17 is also suppressed in the modified example 1-2. It is also understood that the power loss is very small when switching to the small capacitor (1) 20a.

[Modification 1-3]
In the image forming apparatus 1, the ratio of the time for each operation mode to the total operation time is mostly the power-off mode or the energy saving mode. If the standard working time of the office is 8 hours, the operation mode of the image forming apparatus 1 is in the power-off state or the energy saving mode for 16 hours (24 hours-8 hours). In view of this, an example in which the power loss during power-off and the energy saving mode can be minimized is Modification 1-3. The modified example 1-3 is an example in which the capacity of the small-capacitance capacitor (1) 20a is optimized with respect to the configurations of the modified examples 1-1 and 2.

  FIG. 14 is a block diagram illustrating a configuration of an image forming apparatus according to Modification 1-3 of Embodiment 1.

  The image forming apparatus 1 of Modification 1-3 is connected to the image forming apparatus 1 of Modification 1-1 such that an energy saving control signal 37 is transmitted from the control unit 25 to the power supply device 22 and the output capacitor 20. When the image forming apparatus 1 is powered off and in an energy saving mode such as a sleep mode, the energy saving control signal 37 is turned on. The power supply device 22 normally generates two or more types of DC voltage. When the energy saving control signal 37 is turned on, one type remains in the energy saving mode and the other outputs are turned off to save energy.

  Further, the energy saving control signal 37 is connected to the AND element 20e in the previous stage of the switching circuit 20c in the output capacitor 20. By doing so, the switching circuit 20c selects the large-capacity capacitor (2) at the time of a power failure and when the energy saving signal is OFF. The energy saving control signal 37 is inverted and input to the AND element 20e. The AND element 20e according to Modification 1-3 is different from the AND element 20d according to Modification 1-1 in that a control signal from the control unit 25 is inverted and input. The other parts are the same as those in Modification 1-1, and thus a duplicate description is omitted.

  FIG. 15 is a diagram illustrating a sequence of an energy saving control signal and a switching circuit in Modification 1-3. FIG. 15 shows an output signal (power failure signal) of the power failure detection circuit 28, an energy saving control signal output from the control unit 25 to the output capacitor 20, and an operation sequence of the switching circuit 22c.

  As shown in FIG. 15, a small-capacitance capacitor (1) 20a is selected during a non-power failure. The switching circuit 20c selects the capacitor (2) 20b at the time of power failure and energy saving OFF.

  FIG. 16 is a diagram illustrating an operation mode, power consumption, and a capacitor to be used in modification 1-3. FIG. 4A shows a state at the time of non-power failure, and FIG.

  Before the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is in a power OFF state. Since the energy saving control signal 37 is ON in the power OFF state, the switching circuit 20c in FIG. 16 at this time selects the capacitor (1) 20a. Further, as shown in FIG. 15, when the energy saving control signal 37 is OFF, the capacitor type to be used is the capacitor (1) 20a. When the energy saving control signal 37 is OFF and the power failure detection signal is ON, the capacitor type to be used is It shows that it is a capacitor (2) 20b.

  When the main power SW of the image forming apparatus main body 13 is pressed, the image forming apparatus 1 is turned on. When the power is turned on, the energy saving control signal 37 is switched off. Therefore, the capacitor (2) 20b is selected as the capacitor type. By switching in this way, a stable voltage can be supplied from the power storage device 12 even in an operation mode that consumes a large current of the image forming apparatus 1 such as warm-up or printing mode.

 16A and 16B are compared with FIGS. 3A and 3B, it can be seen that the internal loss corresponding to the reactive current of the inverter device 17 is also suppressed in the modified example 1-3. It is also understood that the power loss is very small when switching to the small capacitor (1) 20a.

[Modification 1-4]
FIG. 17 is a circuit diagram illustrating a configuration of a switching circuit according to Modification 1-4 of Embodiment 1. The base of the modification 1-4 is the output capacitor 20 of the modification 1-3.

  As shown in FIG. 17, the switching circuit 20c according to the modified example 1-4 is configured to use a transfer relay and be connected to either the capacitor (1) or the capacitor (2). In the modified example 1-4, when the control signal of the switching circuit 20c is OFF, that is, when the coil voltage of the switching circuit (= relay) 20c is OFF, it is connected to the capacitor (1) having the smaller capacitance component to reduce power loss. The feature is that the power consumption of the relay coil section is not consumed in the desired mode. When the control signal of the switching circuit 20c is ON, that is, when the coil voltage of the switching circuit (= relay) 20c is ON, it is connected to the capacitor (2) 20b having the larger capacitance component. The indefinite period during which the capacitor (1) is switched to the capacitor (2) is determined by the operation time of the relay contact. The time from when the relay coil voltage is switched from OFF to ON until the relay contact is actually turned on is 2 ms to 10 ms.

  Since each other part is comprised similarly to the modification 1-3, the overlapping description is abbreviate | omitted.

  In the first embodiment, two types of capacitors having a small capacity and a large capacity are mounted, and the two capacitors are switched to reduce useless power loss. However, when the capacity of the output capacitor is reduced and the reactive current is reduced to reduce the power loss, the AC output voltage waveform may be distorted. When the AC output voltage waveform is distorted, the zero cross signal shifts, and the digital multi-function peripheral (MFP) operates based on the shifted zero cross signal. Therefore, in the second embodiment, the AC output voltage waveform distortion accompanying the power consumption reduction due to the reduction of the inverter output side capacitance capacitance is corrected, and the MFP is operated without causing the false detection of the zero cross signal.

  FIG. 18 is a block diagram illustrating a schematic configuration of the image forming apparatus according to the second embodiment. The mechanical configuration of the image forming apparatus 1 itself is that shown in FIG.

  In the second embodiment, the power storage device 12 uses the output capacitor 20 of the power storage device 12 of the first embodiment shown in FIG. 2 as a small capacity capacitor (1) 20a and a large capacity capacitor (2) 20b, and a switching circuit 20c. Is provided in front of the output capacitor 20 as the second switching device 14b. Also in the second embodiment, AC power is supplied from the commercial power supply 11, AC power is supplied as it is to the image forming apparatus main body 13 when there is no power failure, and the electric charge stored in the DC power supply battery 16 is AC-converted by the inverter device 17 during power failure. The converted AC power is supplied to the image forming apparatus main body 13. A power failure or non-power failure is detected by a power failure detection circuit 28 in the power storage device 12.

  The power failure detection circuit 28 monitors the AC waveform of the commercial power supply 11, determines that a power failure occurs when the AC waveform stops, and outputs a power failure signal to the power failure detection signal line (switching signal line) 26. If a power failure is detected, the first switching device 14a switches from the commercial power supply 11 to the supply from the AC power source obtained by AC conversion of the charge stored in the DC power supply battery 16 via the power failure detection signal line 26. The DC power supply battery 16 in the power storage device 12 is charged by voltage supply from the charger 15. The first switching device 14a corresponds to the switching device 14 in the first embodiment.

  As in the first embodiment, the inverter device 17 receives, for example, DC 48 V from the DC power supply battery 16, boosts it to DC 200 V by the DC boosting unit 18, converts it to a sinusoidal AC 100 V by the inverter circuit 19 and the smoothing filter circuit 29, and outputs it. The In addition, an output capacitor 20 is provided to stabilize the output voltage.

  The image forming apparatus main body 13 is equipped with a power supply device 22. A DC power is generated from the commercial power supply 11 by a converter unit (AC / DC conversion unit) 33 and converted to a voltage required by the image forming apparatus main body 13. Further, AC power is supplied to the fixing heater 30. The heater control signal 32 output from the control unit 25 controls ON / OFF of the triac 31 and supplies power to the fixing heater 30.

  The load 24 is a load in the image forming apparatus main body 13, and the control unit 25 controls the image forming apparatus 1, grasps the operation state of the image forming apparatus main body 13, and connects the power storage device 12 with a signal line 27. The control unit 21 of the power storage device 12 communicates with each other, and is connected to the second switching device 14b through a signal line 27. A large capacitor 23 is connected to the input side of the power supply device 22 so that the output of the power supply device 22 can be maintained even if the power supply to the image forming apparatus main body 13 is temporarily cut off by the stored charge.

  When there is no power failure, power is supplied from the commercial power supply 11 to the image forming apparatus main body 13, but the inverter device 17 is also operating in preparation for a power failure. When a power failure occurs, if the power consumption of the image forming apparatus main body 13 is small (in standby / standby mode), the second switching device 14b has a path on the capacitor (1) side where the capacity of the output capacitor 20 is small. Switch to.

  Other parts not specifically described are configured in the same manner as the power storage device 12 and the image forming apparatus main body 13 of the first embodiment.

  FIG. 19 is a diagram showing a difference in reactive current depending on the capacitance of the output capacitor 20 in FIG. In the prior art, a large-capacity capacitor (output capacitor 20) is mounted on the output of the inverter device 17 so as to withstand the nonlinear current to the fixing heater 30. When the capacity of the output capacitor 20 is large, the reactive current flowing through the capacitor also increases. Therefore, useless power is consumed even in the standby / standby mode of the image forming apparatus main body 13 where the nonlinear current to the fixing heater 30 is small. Therefore, in the second embodiment, the capacity of the output capacitor 20 subsequent to the inverter circuit 19 is switched to the small capacity side by the second switching device 14b to reduce the reactive current, thereby realizing low power consumption.

  FIG. 20 is a diagram showing an AC output voltage waveform output from the inverter circuit 19 input to the image forming apparatus main body 13. FIG. 4A shows an example when voltage distortion is detected using the capacitance of the output capacitor as a parameter, and FIG. 4B shows an example when voltage distortion is detected using the switching frequency of the inverter as a parameter. In the conventional technique, since the capacity of the output capacitor 20 is large, the distortion of the AC output voltage waveform of the inverter circuit 19 is small (FIG. 20A, distortion: V1). On the other hand, when the second switching device 14b is connected to the small-capacitance capacitor 20b, the capacitance decreases, so that the distortion of the AC output voltage waveform of the inverter circuit 19 increases (FIG. 20 (a), distortion: V2).

  When the inverter is driven at the same switching frequency as in the prior art while being connected to the small-capacitance capacitor 20b by the second switching device 14b, the voltage distortion increases because the capacitor capacity is small (FIG. 20 (b), distortion: V2 ). In the second embodiment, the inverter is driven at a higher switching frequency than in the conventional technique. Thereby, even if the capacitor capacity is small, the voltage distortion can be kept small (FIG. 20B, distortion V3). In this embodiment, the voltage distortion is suppressed to be small by controlling the switching frequency so that the distortion V3 is the same as the distortion V1.

  FIG. 21 is a diagram illustrating the influence on zero-cross detection due to the magnitude of output voltage distortion. FIG. 4A is a diagram showing an example of a zero cross abnormality, and FIG. 4B is a diagram showing an example of no abnormality.

  If the output capacitor capacity is reduced to reduce the reactive current, the voltage distortion increases as shown in FIG. As a result, a zero cross point often occurs in addition to a normal zero cross point, and the abnormality detection frequency increases (FIG. 21A). Therefore, in the second embodiment, the output capacitor capacity is reduced and the switching frequency of the inverter circuit 19 is increased. Thereby, voltage distortion becomes small and a zero cross abnormality can be suppressed (FIG.21 (b)).

  FIG. 22 is a diagram showing timing for changing the switching frequency of the inverter circuit 19. As shown in FIG. 20, when the switching frequency of the inverter circuit 19 is constantly increased, the switching loss increases and the power consumption increases. This eliminates the meaning of reducing the capacity of the output capacitor 20. Therefore, an increase in switching loss is prevented by increasing the switching frequency of the inverter circuit 19 only in a period during which the zero-cross signal is output (period in which the zero-cross detection is performed).

The mechanism is shown below.
(1) Vth> input sine wave Since the zero cross signal is detected, the switching frequency of the inverter circuit 19 is increased to suppress the zero cross abnormality.
(2) Vth <input sine wave Since the zero cross signal is not detected, the switching frequency of the inverter circuit 19 is lowered to prevent an increase in switching loss.

  Note that the threshold value Vth is a value that is compared with the input sine wave in order to distinguish between a period in which the zero cross signal is detected and a period in which it is not detected. In FIG. 22, the period between both positive and negative Vths across the zero cross point is also referred to as the vicinity of the zero cross point.

  FIG. 23 is a flowchart showing a processing procedure when the switching frequency of the inverter circuit 19 is changed. This process is executed by each control function unit including the control unit 21 of the power storage device 12 based on the control signal of the control unit 25 of the image forming apparatus main body 13.

  First, it is checked whether or not a power failure has occurred in the power failure detection circuit 28 in the power storage device 12 (step S101: hereinafter simply indicated by S). In S101, until the occurrence of a power failure is detected (S101: No), the first switching device 14a is switched to the commercial power supply 11 side (S102). When the fixing heater 30 in the image forming apparatus main body 13 is turned on (S103: Yes), the second switching device 14b is switched to the large-capacitance capacitor (2) 20b to prepare for the nonlinear current of the fixing heater 30 (S104). . When the fixing heater 30 is not lit (S103: No), the second switching device 14b is switched to the capacitor (1) 20a on the small capacity side to reduce the reactive current (S105). This loop is repeated until a power failure occurs.

  On the other hand, when the power failure detection circuit 28 detects the occurrence of a power failure (S101: Yes), the first switching device 14a operates based on the detected output, and the power source is switched from the commercial power source 11 to the inverter device 17 side (S106). ). When the inverter circuit 19 always performs the high-frequency switching shown in FIG. 22, the switching loss increases, so the period for performing the high-frequency switching is limited. At that time, the power supply voltage of the commercial power supply 11 crosses the set threshold value Vth (S107). After crossing, the input voltage is compared with the threshold value Vth (S108), and the switching speed is determined from the magnitude relationship.

  That is, if the input voltage is equal to or lower than the threshold value Vth (S108: Yes), the switching frequency of the inverter circuit 19 is increased (S110), and the process returns to S101. If the input voltage is larger than the threshold value Vth (S108: No), the switching frequency of the inverter circuit 19 is lowered (S109), and the process returns to S101. The operations of S108, S109, S110 → S101 are repeated, and control is performed so that the power supply voltage of the commercial power supply 11 crosses the set threshold value Vth.

  As described above, the present embodiment switches the magnitude of the capacitance of the output capacitor (capacitor) 20 connected to the output side of the inverter device 17 in accordance with the operation mode (output load current) on the image forming apparatus main body 13 side. And a control means for increasing the switching frequency of the inverter circuit 19 when switching so as to decrease the capacity of the output capacitor 20. Thereby, the AC output voltage waveform distortion accompanying the power consumption reduction by the reduction of the inverter output side capacitance capacitance can be corrected. As a result, the digital multi-function peripheral (MFP) can be operated without causing erroneous detection of the zero cross signal.

  When distortion occurs in the AC input voltage waveform to the image forming apparatus 1, a malfunction of the fixing heater control occurs due to erroneous detection of the zero cross point. If a problem is caused, stable operation is impaired. At the time of controlling the fixing heater, it is necessary not to cause distortion in the AC input voltage waveform to the image forming apparatus 1. Therefore, in the third embodiment, the power loss of the power storage device 12 connected to the image forming apparatus 1 is reduced without impairing the stable operation of the image forming apparatus 1.

  FIG. 24 is a diagram showing a schematic configuration of the image forming apparatus 1 according to Example 3 in the embodiment of the present invention. The image forming apparatus 1 itself is the same as that shown in FIG. 4 of the first embodiment, and the internal configuration is basically the same as that shown in FIG. 1 of the first embodiment. This embodiment is also similar in that the capacitor capacity is changed by switching the small-capacitance capacitor (1) 20a and the large-capacitance capacitor (2) 20b by the switching circuit 20c during a non-power failure and during a power failure.

  In FIG. 24, the image forming apparatus 1 basically includes a power storage device 12, an image forming device main body 13, and a switching device 14. The power storage device 12 basically includes a charger (AC / DC unit) 15, a DC power supply battery 16, a DC boosting unit (DC / DC unit) 18, an inverter device 17, and a control unit 21. The inverter device 17 includes an inverter circuit (drive circuit) 19, a smoothing filter circuit 29, and an output capacitor 20. Output capacitor 20 further includes a small-capacitance capacitor (capacitor) (1) 20a, a large-capacity capacitor (capacitor) (2) 20b, and a switching circuit 20c.

  The image forming apparatus main body 13 includes a control unit 25 and a power supply device 22. The power supply device 22 further includes a zero cross detection unit 38 that detects a zero cross point. The zero-cross detection unit 38 is connected to the subsequent stage of the switching device 14 and outputs a zero-cross signal 39 indicating a zero-cross point to the control unit 25 based on the input power waveform. The control unit 25 includes a zero cross necessity / unnecessity determination unit 40, and outputs a switching signal 41 to the switching circuit 20 c of the output capacitor 20 based on the zero cross signal 39 detected by the zero cross detection unit 38.

  The control unit 21 in the power storage device 12 includes a zero-cross detection unit 21a, and when generating the output waveform of the inverter circuit 19, an FB (feedback) is performed so as not to make a difference with respect to a pre-stored reference sine wave. Switching control is performed while applying. Other parts not specifically described are configured in the same manner as in the first embodiment and function in the same manner.

  Also in the third embodiment, the switching device 14 is used to supply power from the AC commercial power source to the image forming apparatus main body 13 when there is no power outage, and the charge stored in the DC power source battery 16 is AC converted during the power outage. Switch to AC power supply. When it is determined from the operation mode of the image forming apparatus main body 13 that the zero cross point is used, the capacitor (2) 20b having a large capacity is switched. When it is determined that the zero cross point is not used, the capacitor (1) 20a having a small capacity is switched. In this way, the capacity of the output capacitor 20 is reduced only when distortion of the output waveform can be tolerated. Thereby, power saving can be realized without impairing the stable operation of the apparatus.

  FIG. 25 is a diagram illustrating a method of generating an inverter output waveform.

  The zero cross detector 21a performs comparison with the reference sine wave 21b by the AVR 21c, thereby switching the pulse ON until the voltage of the reference sine wave 21b is exceeded, and switching the pulse OFF when the voltage of the reference sine wave 21b is exceeded. By repeating the process at 21p, the inverter output waveform 21e is generated. Reference numeral 21d represents a switching frequency. The inverter output waveform 21e is an output voltage waveform.

  FIG. 26 is a diagram illustrating an inverter output waveform when the output capacitor 20 is switched.

  In particular, when the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a by the switching circuit 20c, the capacitance is determined from the L inductor capacity of the smoothing filter circuit 29 and the small-capacitance capacitor (1) in FIG. Since the ripple voltage increases, distortion of the inverter output waveform 21e appears significantly. As a result, a zero-cross false detection point occurs. If a zero-cross false detection point occurs at the timing when the soft start / stop control of the fixing heater 30 is performed, a malfunction of the system is caused.

  On the other hand, the occurrence of false detection of zero crossing at a timing at which there is no fear of causing a malfunction is acceptable. The soft start / stop control of the fixing heater 30 means that the lighting time is gradually increased at the start of lighting in order to suppress inrush current and voltage fluctuation at the time of lighting of the fixing heater 30 at the start, and the opposite control at the time of stop. It is a control method to perform.

  FIG. 27 is an enlarged view of the inverter output waveform 21e. In FIG. 27, the solid line is the inverter output waveform before switching the capacity of the output capacitor 20 to the small capacity capacitor (1) 20a, and the dotted line is the capacity switching of the output capacitor 20 to the small capacity capacitor (1) 20a. It is the inverter output waveform after a while. From FIG. 27, it can be seen that when the capacitance of the output capacitor 20 is switched to the capacitor (1) 20a having a small capacitance, the ripple voltage increases and the waveform distortion (deviation) with respect to the reference sine wave 21b increases.

  FIG. 28 is a flowchart illustrating the processing procedure of the third embodiment in which the capacitance of the output capacitor 20 is selected based on the determination result of the zero cross necessity / unnecessity determination unit 40.

  In FIG. 28, first, the output capacitor 20 is switched to a small-capacitance capacitor (1) 20a to reduce power loss (S201). Next, it is determined whether the image forming apparatus 1 is in a state of using the zero cross signal 39 (S202). If not used (S202: No), it waits until it is used. When the zero-cross signal 39 is used (S202: Yes), the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b so that the inverter output waveform distortion does not occur, so that stable operation is not impaired.

  In this state, the state (machine state) of the image forming apparatus main body 13 is monitored (S204), and it is determined whether the control unit 25 of the image forming apparatus main body 13 is using the zero cross signal 39 (S205). When used (S205: Yes), the process proceeds to S204 and the state of the image forming apparatus main body 13 (machine state), that is, whether or not a new control element is generated (using the zero-cross signal 39) is monitored. To do. When not used (S205: No), there is no problem even if the inverter output waveform distortion occurs, so the process proceeds to S201, and the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a.

  As described above, according to the third embodiment, when the zero cross is used, the output capacitor 20 is switched to the large capacity capacitor (2) 20b so that the inverter output waveform distortion does not occur. Loss can be suppressed and power loss can be reduced.

[Modification 3-1]
FIG. 29 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to Modification 1 (hereinafter referred to as Modification 3-1) in Embodiment 3. The modified example 3-1 is an example in which the output capacitor 20 is controlled to be switched to the large-capacitance capacitor (2) 20b only in the operation mode in which the soft start / soft stop control of the fixing heater 30 is performed.

  The image forming apparatus 1 according to Modification 3-1 is obtained by replacing the zero cross necessity / unnecessity determination unit 40 of the control unit 25 of the image forming apparatus 1 of Example 3 shown in FIG. 24 with a fixing soft start determination unit 42. is there. Since the other configuration is the same as that of the image forming apparatus 1 according to the third embodiment shown in FIG. 24, the same reference numerals are given to the same components, and redundant description is omitted.

  In Modification 3-1, when it is determined that the fixing heater soft start / stop control is to be executed from the operation mode of the image forming apparatus main body 13, the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b. On the other hand, when it is determined not to execute the fixing heater soft start / stop control, the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a. Thus, in the modified example 3-1, the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be allowed.

  FIG. 30 is a flowchart showing the processing procedure of the modified example 3-1, in which the capacity of the output capacitor 20 is selected based on the determination result of the fixing soft start determination unit 42.

  In FIG. 30, first, the output capacitor 20 is switched to the smaller capacitor (1) 20a to reduce power loss (S301). Next, it is determined whether or not the image forming apparatus 1 executes the fixing heater soft start control (S302). When not executing (S302: No), it waits until it executes. When it is executed (S302: Yes), the output capacitor 20 is switched to the capacitor (2) 20b having a large capacity so that the inverter output waveform distortion does not occur (S303), so that the stable operation is not impaired.

  In this state, the state (machine state) of the image forming apparatus main body 13 is monitored (S304), and the control unit 25 of the image forming apparatus main body 13 determines whether or not to execute fixing heater soft start control (S305). If it is to be executed (S305: Yes), the process proceeds to S304 and the state of the image forming apparatus main body 13 is directly monitored, that is, whether or not a new control element is generated (necessity of fixing soft start / stop control). . If it is not used (S305: No), there is no problem even if the inverter output waveform distortion occurs. Therefore, the process proceeds to S301, and the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a.

  As described above, according to the modified example 3-1, since the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be permitted, power saving can be realized without impairing the stable operation of the image forming apparatus 1. can do.

[Modification 3-2]
FIG. 31 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to Modification 2 (hereinafter referred to as Modification 3-2) in Embodiment 3. The modified example 3-2 is an example in which the control of switching the output capacitor 20 to the large-capacitance capacitor (2) 20b is performed by predicting in advance the timing of the fixing heater non-lighting state from the temperature state of the image forming apparatus main body 13.

  The image forming apparatus 1 according to Modification 3-2 is obtained by replacing the zero cross necessity / unnecessity determination unit 40 of the control unit 25 of the image forming apparatus 1 of Example 3 shown in FIG. . Since the other configuration is the same as that of the image forming apparatus 1 according to the third embodiment shown in FIG. 24, the same reference numerals are given to the same components, and redundant description is omitted.

  In the modified example 3-2, when it is determined that the fixing heater 30 is in a lighting state from the fixing temperature state of the image forming apparatus main body 13, the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b. On the other hand, when it is determined that the fixing heater 30 is not in a lighting state, the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a1. In Modification 3-2, the capacity of the output capacitor 20 is reduced only when distortion of the inverter output waveform can be tolerated. Thereby, power saving can be realized without impairing the stable operation of the image forming apparatus 1. The fixing temperature is continuously measured by a temperature sensor (not shown), and lighting control of the fixing heater 30 is performed while the control unit 25 monitors the fixing temperature. This lighting control is performed based on, for example, the heater control signal 32 shown in the first embodiment.

  FIG. 32 is a flowchart showing the processing procedure of the modified example 3-2 for selecting the capacity of the output capacitor 20 based on the determination result of the fixing lighting determining unit 43.

  In FIG. 32, first, the output capacitor 20 is switched to the smaller capacitor (1) 20a to reduce the power loss (S401). Next, it is determined from the temperature state whether the image forming apparatus 1 is in a state of turning on the fixing heater 30 (S402). When it is not in a lighting state (S402: No), it waits until it becomes a lighting state. When it is executed (S402: Yes), the output capacitor 20 is switched to the capacitor (2) 20b having a large capacity so as not to cause distortion of the inverter output waveform (S403) so as not to impair stable operation.

  In this state, the state (machine state) of the image forming apparatus main body 13 is monitored (S404), and the image forming apparatus main body 13 determines whether or not the fixing heater 30 is lit from the fixing temperature state (S405). When it is lit (S405: Yes), the process proceeds to S404 and the fixing temperature state (machine state) of the image forming apparatus main body 13 is monitored as it is. When it is not used (S405: No), the inverter output waveform distortion is detected. Since there is no problem even if it occurs, the process proceeds to S401, and the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a1.

  As described above, according to the modified example 3-2, the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be allowed. Therefore, power saving can be realized without impairing the stable operation of the image forming apparatus 1. can do.

[Modification 3-3]
FIG. 33 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to Modification 3 (hereinafter referred to as Modification 3-3) in Embodiment 3. In Modified Example 3-3, control is performed to switch the output capacitor 20 to the large-capacitance capacitor (2) 20b in synchronization with the ON / OFF signal of the fixing relay (FIG. 11: fixing relay 36) of the heater drive circuit of the power supply device 22. It is an example to do.

  In the image forming apparatus 1 according to the modified example 3-3, the zero cross necessity / unnecessity determination unit 40 of the control unit 25 of the image forming apparatus 1 according to the third embodiment illustrated in FIG. 24 is replaced with the fixing relay 0N / OFF determination unit 44. Is. Since the other configuration is the same as that of the image forming apparatus 1 according to the third embodiment shown in FIG. 24, the same reference numerals are given to the same components, and redundant description is omitted.

  In Modification 3-3, when it is determined from the operation mode of the image forming apparatus main body 13 that the fixing relay 36 is turned on, the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b. On the other hand, when it is determined that the fixing relay 36 is turned off, the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a. Thus, in Modification 3-3, the capacity of the output capacitor 20 is reduced only when distortion of the inverter output waveform can be allowed. Thereby, power saving can be realized without impairing the stable operation of the image forming apparatus 1.

  FIG. 34 is a flowchart showing a processing procedure of Modification 3-3 in which the capacity of the output capacitor 20 is selected based on the determination result of the fixing relay ON / OFF determination unit 44.

  In FIG. 34, first, the output capacitor 20 is switched to the smaller capacitor (1) 20a to reduce the power loss (S501). Next, it is determined whether the fixing heater relay of the image forming apparatus main body 13 is on or off (S502). When the relay is OFF (S502: No), it waits until the relay is turned ON. When the relay is ON (S502: Yes), the output capacitor 20 is switched to the capacitor (2) 20b having a large capacity so as not to cause the inverter output waveform distortion (S503) so as not to impair stable operation.

  In this state, the state (machine state) of the image forming apparatus main body 13 is monitored (S504), and it is determined whether the fixing relay 36 of the image forming apparatus main body 13 is ON / OFF (S505). When the fixing relay 36 is ON (S505: Yes), the process proceeds to S504 and the state of the image forming apparatus main body 13 (ON / OFF state of the fixing relay 36) is monitored as it is, and when the fixing relay 36 is OFF ( In S505: No), since there is no problem even if the inverter output waveform distortion occurs, the process proceeds to S501, and the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a1.

  As described above, according to the modified example 3-3, the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be allowed. Therefore, power saving can be realized without impairing the stable operation of the image forming apparatus 1. can do.

[Modification 3-4]
FIG. 35 is a diagram illustrating an outline of a main configuration of an image forming apparatus 1 according to Modification 4 (hereinafter referred to as Modification 3-4) in Embodiment 3. The modified example 3-4 includes means for switching the output capacitor 20 to the large-capacitance capacitor (2) 20b in synchronization with the transition signal to the energy saving mode (FIG. 14: energy saving control signal 37) of the image forming apparatus main body 13. It is an example.

  The image forming apparatus 1 according to Modification 3-4 is obtained by replacing the zero cross necessity / unnecessity determination unit 40 of the control unit 25 of the image forming apparatus 1 of Example 3 shown in FIG. is there. Since the other configuration is the same as that of the image forming apparatus 1 according to the third embodiment shown in FIG. 24, the same reference numerals are given to the same components, and redundant description is omitted.

  In Modification 3-4, the energy saving transition state of the image forming apparatus main body 13 is confirmed, and when it is determined that the image forming apparatus body 13 is not in the energy saving mode state, the output capacitor 20 is switched to the large-capacitance capacitor (2) 20b. On the other hand, when it is determined that the state is the energy saving mode, the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a. Whether or not it is in the energy saving mode state can be determined, for example, based on whether or not the energy saving control signal 37 described in Modification 1-3 with reference to FIG. Since the fixing heater control is not performed in the energy saving mode state, distortion of the inverter output waveform can be allowed. Thus, in Modification 3-4, the capacity of the output capacitor 20 is reduced only when distortion of the inverter output waveform can be tolerated. Thereby, power saving can be realized without impairing the stable operation of the image forming apparatus 1.

  FIG. 36 is a flowchart showing a processing procedure of Modified Example 3-4 for selecting the capacity of the output capacitor 20 based on the determination result of the energy saving mode state confirmation unit 45.

  In FIG. 36, first, the output capacitor 20 is switched to the smaller capacitor (1) 20a to reduce the power loss (S601). Next, it is determined whether the image forming apparatus main body 13 is in the energy saving mode (S602). When the energy saving mode is selected (S602: Yes), when the energy saving mode is not selected (S602: No), the output capacitor 20 is switched to the capacitor (2) 20b having a large capacity so that the inverter output waveform distortion does not occur (S603), and stable operation is performed. Do not damage.

  In this state, the state (machine state) of the image forming apparatus main body 13 is monitored (S604), and it is determined whether or not the image forming apparatus main body 13 is in the energy saving mode (S605). If it is not in the energy saving mode (S605: No), the process proceeds to S604 and the state of the image forming apparatus main body 13 (whether or not the energy saving mode is set) is monitored as it is. If it is in the energy saving mode (S605: Yes), there is no problem even if the inverter output waveform distortion occurs. Therefore, the process proceeds to S601, and the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a1.

  As described above, according to the modified example 3-4, the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be allowed. Therefore, power saving can be realized without impairing the stable operation of the image forming apparatus 1. can do.

  As described above, if the present invention is adapted to the present embodiment, the following effects can be obtained. In the following description, each component in the claims corresponds to each part of the present embodiment, and when the terms are different, the latter is shown in parentheses, and a corresponding reference symbol is attached. The relationship between the two was clarified.

  1. A chargeable / dischargeable battery (DC power supply battery 16) that is charged by power supplied from outside (commercial power supply 11), an inverter device 17 that converts the power of the battery into AC power and outputs it, and an external (commercial power supply) 11) or a power supply device 22 that supplies power supplied from the inverter device 17 to each load 24 and the fixing heater 30, and power supplied to the power supply device 22 from the outside (commercial power supply 11). In the image forming apparatus 1 including a first switching unit (switching device 14) that switches to either the supplied power or the power output from the inverter device 17, the inverter device 17 has a large or small capacity component. A plurality of capacitors (capacitor (1) 20a, capacitor (2) 20b) and According to the present embodiment including the second switching means (switching circuit 20c) for switching to any one of the sensors (1) 20a and (2) 20b), a capacitor having a small capacitance component is output during a non-power failure, When power supply is required from the battery (DC power supply battery 16) or the power storage device 12 to the image forming apparatus main body 13 when a power failure occurs, the capacitor can be switched to a capacitor having a large capacitance component. As described above, by changing the capacitor capacity to be used in accordance with the non-power failure / power failure operation mode, it is possible to reduce the power loss inside the inverter device 17, particularly the capacitor. In addition, about the magnitude of a capacity | capacitance component, it can implement by the capacity | capacitance ratio of about 10 to 1, for example.

  2. The second switching means (switching circuit 20 c) switches to a capacitor (capacitor (2) 20 b) having a larger capacitance component when supplying power from the inverter device 17 to the power supply device 22. When the power is directly supplied from the inverter device 17 to the power supply device 22 in the case of a power failure, the power supply device 22 is switched to the capacitor (capacitor (1) 20a having a smaller capacitance component). Is the same internal loss as before, but in the operation mode in which power is not supplied from the power storage device 12 during a non-power failure, the output capacitor 20 is switched to the small-capacitance capacitor (1) 20a. The internal loss corresponding to the reactive current is suppressed, and the power loss of the capacitor can be reduced.

  3. According to the present embodiment, the second switching means (switching circuit 20c) switches to a capacitor having a smaller capacitance component at the time of a power failure and in an operation mode with low power consumption. Since the output capacitor 20 is sometimes switched to the capacitor (1) 20a having a small capacity, the internal loss corresponding to the reactive current of the inverter device 17 is suppressed as compared with the conventional case, and the power loss of the capacitor can be reduced.

  4). According to the present embodiment including the frequency changing means (control unit 25) that changes the switching frequency of the inverter device 17 according to the operation mode of the image forming apparatus 1, the switching frequency is set according to the capacitance of the switched capacitor. Can be changed. For this reason, it becomes possible to suppress the voltage distortion of the inverter apparatus 17 small, and a zero cross abnormality can be eliminated.

  5. In the present embodiment, the frequency changing means (the control unit 25) changes the frequency to a high frequency switching frequency during a period in which the zero cross point of the reference sine wave 21b of the inverter device 17 is detected, and changes to a low frequency switching frequency in other periods. Accordingly, the switching frequency is increased during the period in which the zero-cross signal is detected to suppress the zero-crossing abnormality, and an increase in switching loss can be prevented without changing the switching frequency in the period in which the zero-cross signal is not detected.

  6). Detection means (zero-cross detection unit 38) for detecting the zero-cross point of the reference sine wave 21b of the inverter device 17 and determination means (zero-cross required / determined) for determining whether or not the zero-cross point is used for controlling the fixing heater 30. Unnecessary determination unit 40), and the second switching unit (switching circuit 20c) includes a plurality of capacitors (capacitor (1)) based on a determination result of the determination unit (zero cross necessity / unnecessity determination unit 40). According to the present embodiment, which is switched to either the capacitor 20a or the capacitor (2) 20b), when there is a possibility of causing a malfunction due to the zero-cross signal 39, the output capacitor 20 is a large-capacity capacitor so that the inverter output waveform distortion does not occur. (2) When there is no fear of causing malfunction by switching to 20b, the output capacitor 20 Is switched to the capacitor (1) of small capacity, to suppress the internal loss of the reactive current component of the inverter device 17, it is possible to reduce the power loss.

  7). In the present embodiment, the second switching means (switching circuit 20c) switches to the capacitor (capacitor (2) 20b) having the larger capacitance component only in the operation mode in which the soft start / soft stop control of the fixing heater 30 is performed. Accordingly, since the capacity of the output capacitor 20 is reduced only when distortion of the inverter output waveform can be allowed, power saving can be realized without impairing the stable operation of the image forming apparatus 1.

  8). The second switching means (switching circuit 20c) predicts in advance the timing of the fixing heater non-lighting state from the temperature state of the image forming apparatus 1, and the capacitor on the side having a larger capacitance component before the power consumption increases. According to this embodiment switched to (capacitor (2) 20b), the capacity of the output capacitor 20 is reduced only when the distortion of the inverter output waveform can be tolerated. Therefore, power saving can be achieved without impairing the stable operation of the image forming apparatus 1. Can be realized.

  9. A step of charging power supplied from the outside (commercial power supply 11) to a chargeable / dischargeable battery (DC power supply battery 16), and the inverter device 17 converts the power of the battery (DC power supply battery 16) into AC power. A step of outputting, a step of supplying power supplied from the outside (commercial power supply 11) or power output from the inverter device 17 from the power supply device 22 to each load 24 and the fixing heater 30, and supply to the power supply device 22 Switching the electric power to be supplied from the outside or the electric power output from the inverter device 17 by the first switching means (the switching device 14), and the electric power from the inverter device 17 to the power supply device 22 When supplying, switch to the capacitor with the larger capacitance component (capacitor (2) 20b) A step of switching to the capacitor (capacitor (1) 20a) having a smaller capacitance component by the second switching means (switching circuit 20c) when power is directly supplied from the power source 11) to the power supply device 22. According to the embodiment, the 1. The effect described in the above can be achieved. 9. Is 1. Are redefined in the method category, and the details of each step are described in the operation description of the apparatus.

  10. A procedure (for example, the DC power supply battery 16 in the power storage device 12) for charging the computer (CPU of the control unit 25) with electric power supplied from the outside (commercial power supply 11) to a chargeable / dischargeable battery (DC power supply battery 16) And a procedure for converting the power of the battery (DC power supply battery 16) to AC power by the inverter device 17 and outputting the AC power (for example, during a power failure, the battery is stored in the DC power supply battery 16). AC power converted into AC by the inverter device 17 is described as being supplied to the image forming apparatus main body 13) and power supplied from the outside (commercial power supply 11) or power output from the inverter device 17. Procedures for supplying each load 24 and fixing heater 30 from the power supply device 22 (for example, the power supply device 22 is provided and AC / DC (Changing unit 33 generates DC power from AC power and supplies AC power to fixing heater 30. Load 24 indicates the load in image forming apparatus main body 13, and power is supplied from power supply 22) And the first switching means (switching device 14) switches the power supplied to the power supply device 22 to either the power supplied from the outside (commercial power supply 11) or the power output from the inverter device 17. When power is supplied from the inverter device 17 to the power supply device 22 by the procedure (for example, S102 and S106) and the second switching means (switching circuit 20c), the capacitor (capacitor (2) 20b) having a larger capacitance component is supplied. When the power is directly supplied from the outside (commercial power supply 11) to the power supply device 22, the capacitance component is small. To switch the the capacitor (the capacitor (1) 20a) (e.g., S105) according to the program of the present embodiment for executing a, a, a 1. The effect described in the above can be achieved. 10. Is 9. This method is defined as a program for causing a computer to execute, and each procedure is described in detail corresponding to the operation description of the apparatus.

  In the above-described embodiment, the program executed by the CPU is described as being stored in advance in a ROM or the like. However, the present invention is not limited to this, and the program executed in the image forming apparatus 1 according to this embodiment can be installed. In a format or executable format, and recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk), etc. You can also.

  Further, the program executed by the image forming apparatus 1 according to the present embodiment can be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. In addition, the program executed by the image forming apparatus 1 according to the present embodiment can be configured to be provided or distributed via a network such as the Internet.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention, and all technical matters included in the technical idea described in the claims are included. The subject of the present invention. The above embodiment shows a preferable example, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in this specification, These are included in the technical scope described in the appended claims.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Commercial power supply 12 Electric power storage apparatus 13 Image forming apparatus main body 14 Switching apparatus (1st switching means)
16 DC power supply battery 17 Inverter device 20 Output capacitor 20a Capacitor (1)
20b Capacitor (2)
20c switching circuit (second switching means)
21b Reference sine wave 22 Power supply device 24 Load 25 Control unit (frequency changing means)
30 Fixing heater 38 Zero cross detection part (detection means)
39 Zero-cross signal 40 Zero-cross required / unnecessary determination unit (determination means)

JP 2001-253152 A

Claims (10)

A chargeable / dischargeable battery that is charged by externally supplied power;
An inverter device that converts the power of the battery into AC power and outputs the power; and a power supply device that supplies power supplied from the outside or power output from the inverter device to each load and the fixing heater;
First switching means for switching power supplied to the power supply device to either power supplied from the outside or power output from the inverter device;
In an image forming apparatus comprising:
The inverter device is
A plurality of capacitors having different capacitance components,
Second switching means for switching to any of the plurality of capacitors;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
The second switching means switches to a capacitor having a larger capacitance component when power is supplied from the inverter device to the power supply device, and when power is supplied directly from the outside to the power supply device, the second switching means has a smaller capacitance component side. An image forming apparatus characterized by switching to a capacitor. The image forming apparatus according to claim 1, wherein
The image forming apparatus according to claim 2, wherein the second switching unit switches to a capacitor having a smaller capacitance component during a power failure and in an operation mode with low power consumption. The image forming apparatus according to claim 1.
An image forming apparatus comprising frequency changing means for changing a switching frequency of the inverter device in accordance with an operation mode of the image forming apparatus. The image forming apparatus according to claim 4.
2. The image forming apparatus according to claim 1, wherein the frequency changing means changes the high frequency switching frequency in the vicinity of the zero cross point of the reference sine wave of the inverter device, and changes to the low frequency switching frequency during other periods. The image forming apparatus according to claim 1.
Detecting means for detecting a zero cross point of a reference sine wave of the inverter device;
Determination means for determining whether to use the zero cross point for controlling the fixing heater;
With
The image forming apparatus, wherein the second switching unit switches to one of the plurality of capacitors based on a determination result of the determination unit. The image forming apparatus according to claim 6.
The image forming apparatus according to claim 2, wherein the second switching unit switches to a capacitor having a larger capacitance component only in an operation mode in which soft start / soft stop control of the fixing heater is performed. The image forming apparatus according to claim 6.
The second switching unit predicts in advance the timing of the non-lighting state of the fixing heater from the temperature state of the image forming apparatus, and switches to a capacitor having a larger capacitance component before power consumption increases. An image forming apparatus. Charging a chargeable / dischargeable battery with power supplied from the outside;
Converting the power of the battery into AC power by an inverter device and outputting the power; and
Supplying power supplied from the outside or power output from the inverter device to each load and halogen heater from a power supply device;
A step of switching the power supplied to the power supply device to either the power supplied from the outside or the power output from the inverter device by a first switching means;
When power is supplied from the inverter device to the power supply device, the capacitor is switched to a capacitor having a larger capacitance component. When power is supplied directly from the outside to the power supply device, the capacitor having a smaller capacitance component is switched to the capacitor by the second switching means. Switching process;
A power supply method comprising: On the computer,
A procedure for charging power supplied from outside to a chargeable / dischargeable battery,
A procedure of converting the power of the battery into AC power by an inverter device and outputting the AC power;
A procedure of supplying power supplied from the outside or power output from the inverter device to each load and the fixing heater from a power supply device;
A procedure for switching the power supplied to the power supply device to one of the power supplied from the outside or the power output from the inverter device by the first switching means;
When power is supplied from the inverter device to the power supply device by the second switching means, the capacitor is switched to a capacitor having a larger capacitance component, and when power is supplied directly from the outside to the power supply device, the capacitor having a smaller capacitance component is switched. To switch to
A program for running