Ac output control element cooling device, and image formation device
Patent Information
- Application Number
- JP2023129929
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-08-09
- Publication Date
- 2025-02-21
Smart Images
Figure 2025025288000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a cooling device for an AC output control element and an image forming apparatus. [Background technology]
[0002] In electrophotographic image forming apparatuses, power is supplied to the heater in the fixing unit via an AC output control element (e.g., a triac) for controlling power. To prevent damage to the element (triac) due to heat generation, a cooling fan is provided and the fan's rotation speed is known to be variably controlled, and there is technology to control the rotation speed by fluctuations in the input voltage.
[0003] Patent Document 1 discloses a configuration in which the airflow rate of a fan is increased when the input voltage falls below a lower limit, in order to prevent a shortened life span or breakdown of an AC output control element for heater control due to thermal stress. In more detail, when the input voltage level (detection voltage) drops, the output from the second voltage comparator is corrected to increase the switching frequency of the switching semiconductor Q1 above normal. This discloses a configuration in which the voltage applied to the fan 17 is increased, and the airflow rate of the fan 17 is instantly increased by the ratio of the drop in the input voltage.
[0004] However, in conventional image forming apparatuses, when the voltage drops, the fan flow rate is increased to protect the AC output control element from being cooled, but this causes problems such as fan noise and increased current consumption.
[0005] Patent Document 1 discloses controlling the operation of a fan using an input voltage. However, Patent Document 1 does not solve the problems of fan noise and increased current consumption. Summary of the Invention [Problem to be solved by the invention]
[0006] SUMMARY OF THE PRESENT EMBODIMENT An embodiment of the present invention has been made in view of the above, and has an object to reduce the noise of the blower and the current consumption by controlling the drive start time of the blower. [Means for solving the problem]
[0007] In order to solve the above problem, the invention described in claim 1 is a cooling device for an AC output control element, comprising: a heating unit; a temperature control unit that controls the heating temperature by controlling the power supplied from an AC power source to the heating unit using an AC output control element; a blower that suppresses a rise in temperature of the AC output control element; and a drive unit that drives the blower, wherein the cooling control unit controls on and off of the drive unit to maintain the temperature of the AC output control element within an allowable temperature range; a temperature sensor that measures the temperature of the heating unit; a temperature rise rate calculation unit that calculates a temperature rise rate in a predetermined period based on the temperature of the heating unit; and an input voltage estimation unit that estimates an input voltage estimate value related to the input voltage of the AC power source based on the temperature rise rate, and the cooling control unit determines a drive start time of the blower based on the input voltage estimate value. Effect of the Invention
[0008] According to the present invention, by controlling the time when the blower starts to be driven, it is possible to reduce the noise of the blower and to reduce the current consumption. [Brief description of the drawings]
[0009] [Figure 1] 1 is a cross-sectional view showing a schematic mechanical configuration of an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] 1 is a circuit diagram for explaining a configuration of a power supply device mounted on an image forming apparatus according to a first embodiment of the present invention. [Diagram 3] 1 is a functional block diagram showing functions of an image forming apparatus according to a first embodiment of the present invention. [Figure 4]5 is a timing chart showing an overview of fan drive time control by AC power supply voltage in the image forming apparatus according to the first embodiment of the present invention. [Diagram 5] 1A is a graph (part 1) showing an example of the temperature of the AC output control element and elapsed time when the input voltage estimated value of the AC power supply in the image forming apparatus according to the first embodiment of the present invention is different, and FIG. 1B is a diagram (part 1) showing a control table storing an example of the relationship between the input voltage estimated value, the temperature of the AC output control element, and time in the image forming apparatus according to the first embodiment of the present invention. [Figure 6] 4 is a flowchart (part 1) for explaining the operation of the image forming apparatus according to the first embodiment of the present invention. [Figure 7] 5 is a flowchart of a subroutine for explaining the operation of the image forming apparatus according to the first embodiment of the present invention. [Figure 8] 4 is a diagram illustrating a conversion table that stores an example of the relationship between the temperature rise rate of the fixing heater and the input voltage estimated value in the image forming apparatus according to the first embodiment of the present invention. [Figure 9] 10 is a timing chart showing an overview of fan drive time control based on a print-OFF time in an image forming apparatus according to a second embodiment of the present invention. [Figure 10] 1A is a graph (part 2) showing an example of the temperature of the AC output control element when the print OFF time is different in an image forming apparatus according to a second embodiment of the present invention, (b) is a diagram (part 2) showing a control table storing an example of the relationship between the temperature of the AC output control element and time in an image forming apparatus according to a second embodiment of the present invention, and (c) is a diagram (part 3) showing a control table storing an example of the relationship between the print OFF time and the temperature of the AC output control element in an image forming apparatus according to a second embodiment of the present invention. [Figure 11] 10 is a second flowchart illustrating the operation of the image forming apparatus according to the second embodiment of the present invention. [Figure 12]1A is a graph (part 3) showing an example of the temperature of the output control element when the environmental temperature is different in an image forming apparatus according to a third embodiment of the present invention, and FIG. 1B is a diagram (part 4) showing a control table storing an example of the time t for the temperature to rise from the environmental temperature Tk to the upper limit temperature Ttop in an image forming apparatus according to a third embodiment of the present invention. [Figure 13] 13 is a flowchart (part 3) for explaining the operation of the image forming apparatus according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. The present invention has the following configuration in order to reduce the noise of the blower and reduce current consumption by controlling the drive start time of the blower. That is, the cooling device for an AC output control element of the present invention is a cooling device for an AC output control element comprising a heating unit, a temperature control unit that controls the heating temperature by controlling the power supplied from the AC power source to the heating unit using the AC output control element, a blower that suppresses a rise in temperature of the AC output control element, and a drive unit that drives the blower, and is characterized in that it comprises a cooling control unit that controls the drive unit on and off to maintain the temperature of the AC output control element within an allowable temperature range, a temperature sensor that measures the temperature of the heating unit, a temperature rise rate calculation unit that calculates a temperature rise rate in a specified period based on the temperature of the heating unit, and an input voltage estimation unit that estimates an input voltage estimate value related to the input voltage of the AC power source based on the temperature rise rate, and the cooling control unit determines the drive start time of the blower based on the input voltage estimate value. With the above configuration, the blower drive start time can be controlled to reduce the noise of the blower and reduce current consumption. The features of the present invention described above will be described in detail with reference to the following drawings. However, unless otherwise specified, the components, types, combinations, shapes, relative arrangements, etc. described in the embodiments are merely illustrative examples and do not intend to limit the scope of the present invention. The above-mentioned features of the present invention will be described in detail below with reference to the drawings.
[0011] First Embodiment <Image forming device> FIG. 1 is a cross-sectional view showing a schematic mechanical configuration of an image forming apparatus according to a first embodiment of the present invention. As an example of the image forming apparatus according to the first embodiment of the present invention, an image forming apparatus 1 shown in FIG. 1 is adopted. 1 is a digital multifunction machine having a copy function, a printer function, a facsimile function, etc. The application switching key of the operation unit 2a allows the user to select the copy function, the printer function, and the facsimile function by switching between them in sequence. When the copy function is selected, the mode becomes copy mode, when the printer function is selected, the mode becomes printer mode, and when the facsimile mode is selected, the mode becomes facsimile mode. Here, when the user performs a selection operation on a key for selecting a copy function displayed on the operation unit 2a, the image forming apparatus 1 performs the following operation.
[0012] <Copy mode> Referring to FIG. 1, a copy mode will be briefly described as an example of the flow of image formation in image forming apparatus 1. In the copy mode, documents are fed one by one from a stack of documents set in an automatic document feeder (ADF) 2 to an image reading unit 3, and image information of the documents is read by the image reading unit 3. The read image information is then converted into optical information by a writing unit 4 via an image processing means, and a photoconductor drum 6 is uniformly charged by a charger and then exposed to the optical information from the writing unit 4, forming an electrostatic latent image. The image forming unit 5 is a print engine that forms an image on a print sheet. In the image forming unit 5, the electrostatic latent image on the photoconductor drum 6 is developed by the developing unit 7 into a toner image. This toner image is transferred to the transfer paper by the conveyor belt 8. The toner image is fixed on the transfer paper by the fixing unit 9, and the transfer paper is discharged.
[0013] The image forming apparatus 1 is provided with a power supply device 10, which converts power supplied from an AC power supply 12, which is an external power supply, into DC power and supplies the DC power to the loads of the above-mentioned components. In addition, the cooling device for the AC output control element according to the present invention can be applied to appliances other than the image forming apparatus 1, such as microwave ovens, electric water heaters, rice cookers, cooking appliances, washer-dryers, hair dryers, electric stoves, etc.
[0014] <Power supply> FIG. 2 is a circuit diagram for explaining the configuration of a power supply device mounted on the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 includes a power supply device 10, a control board 14, and a halogen heater 25 as its main components. The power supply device 10 includes a DC voltage generating unit 35, which will be described later, and a triac 26 that controls the flow of AC power supplied to the fixing unit. The power supply device 10 generates a DC voltage (24 V, 5 V) from an AC power supply 12, which is a commercial AC power supply, and supplies the generated DC voltage to a control board 14. The power supply device 10 also supplies the AC voltage of the AC power supply 12 to a halogen heater 25 via a triac 26 provided in the power supply device 10. The control board 14 includes a CPU 15a, a ROM 15b, a RAM 15c, and a timer 15d. The CPU 15a includes A / D1, A / D2, A / D3, and A / D4, each of which converts an input analog voltage into digital data.
[0015] The DC voltage generating unit 35 provided in the power supply device 10 is composed of a noise filter 16 that removes noise components from the AC supplied from the AC power supply 12, a diode bridge 17 that full-wave rectifies the AC, an aluminum electrolytic capacitor 18 that smoothes the pulsating component during full-wave rectification, a transformer 19 having primary to tertiary windings, an FET 20 used for switching, an IC 21 that controls the switching timing of the FET 20 based on a signal from the tertiary winding, a diode 22 that rectifies the low-voltage AC induced in the secondary winding of the transformer 19, an aluminum electrolytic capacitor 23 that smoothes the pulsating component, and a switching regulator 24 consisting of a DC / DC converter that generates 5 V from 24 V, and generates DC voltages of 24 V and 5 V from the AC voltage. The CPU 15a controls the supply / cut-off of AC voltage to the halogen heater 25 by providing a TRIAC control signal 27, which is an ON / OFF signal, to the triac . The CPU 15a controls the operations of the various components constituting the image forming apparatus 1 (FIG. 3).
[0016] A temperature sensor 38 is disposed near the triac 26, and a voltage signal proportional to the heat generation temperature of the triac 26 detected by the temperature sensor 38 is input to the A / D2 port. A blower 37 for cooling the triac 26 is disposed near the triac 26, with a power supply terminal of the blower 37 connected to a 24 V power supply and one GND terminal connected to the collector terminal of the transistor 36. The emitter terminal of the transistor 36 is connected to GND, and the base terminal of the transistor 36 is connected to the output port of the CPU 15a.
[0017] When the AC voltage detection circuit 28 shown in FIG. 2 is adopted, it is necessary to convert an AC voltage with a frequency of several tens of Hz into a low voltage that can be detected by the A / D1 port using a transformer 29, a diode bridge 30, and a capacitor 31, so that the transformer becomes large in size in terms of the component configuration. A temperature sensor 38 is disposed near the triac 26, and a voltage signal proportional to the heat generation temperature of the triac 26 detected by the temperature sensor 38 is input to the A / D2 port. The temperature sensor 39a is provided on the side surface of the image forming apparatus 1, and a voltage signal proportional to the environmental temperature Tk detected by the temperature sensor 39a is input to the A / D3 port. A temperature sensor 40 is disposed near the halogen heater 25, and a voltage signal proportional to the heat temperature of the halogen heater 25 detected by the temperature sensor 40 is input to the A / D4 port. A cooling fan 37 for cooling the triac 26 is disposed near the triac 26, and a power supply terminal of the cooling fan 37 is connected to a 24 V power supply, and one GND terminal is connected to the collector terminal of the transistor 36. The emitter terminal of the transistor 36 is connected to GND, and the base terminal of the transistor 36 is connected to the output port of the CPU 15a.
[0018] <Function block diagram> FIG. 3 is a functional block diagram showing functions of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 includes a fixing heater 25a, an AC output control element 26a, a temperature control unit 31a, a blower 37a, a drive unit 36a, a DC power supply 35a, a cooling control unit 50a, and a temperature sensor 38a. The fixing heater 25a (heating unit) is, for example, a halogen heater that can be supplied with AC power from an external power source. A halogen heater has a resistance characteristic in which the lower the temperature, the lower the resistance. Due to this resistance characteristic, an inrush current occurs when the current starts to flow, causing a voltage drop in the external power source. The AC output control element 26a is constituted by a triac 26, and is a switching element for controlling the on / off of the power supplied from the AC power source 12 to the fixing heater 25a. The temperature control unit 31a controls the power supplied from the AC power source 12 to the fixing heater 25a (heating unit) by the AC output control element 26a, thereby controlling the heater temperature. The blower 37a suppresses an increase in the temperature Ts of the AC output control element 26a. The driving unit 36a is constituted by a transistor 36, and drives a blower 37a by supplying power from a DC power supply 35a to the blower 37a.
[0019] The DC power supply 35a is constituted by a DC voltage generating unit 35, and converts the power of the AC power supply 12 into DC power to supply voltages of 24V and 5V. The cooling control unit 50a controls the driving unit 36a to turn on and off in response to fluctuations in the level of the input voltage estimate value Veac in order to maintain the temperature Ts of the AC output control element 26a within an allowable temperature range. The cooling control unit 50a is configured to off Based on this, the time to start driving the blower 37a is determined. The cooling control unit 50a is configured to off Based on this, the time to start driving the blower 37a is determined. The temperature sensor 38a is constituted by the temperature sensor 38, and is disposed in the vicinity of the AC output control element 26a to measure the temperature Ts of the AC output control element 26a. The temperature sensor 39a is constituted by the temperature sensor 39, and is provided on the side surface of the image forming apparatus 1 to measure the environmental temperature Tk. The temperature sensor 40a is constituted by the temperature sensor 40, and is disposed in the vicinity of the fixing heater 25a (heating unit) to measure the temperature of the fixing heater 25a. The print-off time measurement unit 50b measures the print-off time t off Time the following. The temperature rise rate calculation unit 50c calculates the temperature rise rate ΔT (° C. / sec) in a predetermined period based on the temperature of the fixing heater 25a (heating unit). The input voltage estimation unit 50d estimates an input voltage estimate value Veac relating to the input voltage of the AC power supply 12, based on the temperature rise rate ΔT.
[0020] <Fan operation time control> FIG. 4 is a timing chart showing an overview of fan drive time control by AC power supply voltage in the image forming apparatus according to the first embodiment of the present invention. The method of calculating the input voltage estimate value Veac of the AC power supply 12 will be described later with reference to a flowchart of a subroutine shown in FIG. In FIG. 4, the printing time is t 11 ~t 1fe The fan operation time is set to time t 1fs ~t 1fe Let us assume that. When the input voltage estimate value Veac of the AC power supply 12 is low, the current increases to ensure power for the fixing heater 25a (heating unit). Since the current flowing through the AC output control element 26a that controls the supply to the fixing heater 25a increases, the temperature Ts of the AC output control element 26a increases. Conversely, when the input voltage estimate value Veac of the AC power supply 12 is high, the current flowing through the AC output control element 26a is small, and the temperature Ts of the AC output control element 26a is lower than when the voltage is low. When the input voltage estimate value Veac of the AC power source 12 is low, the temperature Ts of the AC output control element 26a becomes high, so the drive start time (t 1fs ) is advanced to prevent a temperature rise, and when the input voltage estimate value Veac of the AC power supply 12 is high, the temperature rise of the AC output control element 26a is small, so the drive start time (t 1fs ) to delay.
[0021] <Graph (part 1)> FIG. 5(a) is a graph (part 1) showing an example of the temperature of the AC output control element and the elapsed time when the input voltage estimated value of the AC power supply in the image forming apparatus according to the first embodiment of the present invention is different. That is, FIG. 5(a) shows an example of the temperature Ts of the AC output control element and the elapsed time t when the input voltage estimate value Veac of the AC power supply is different. The cooling control unit 50a determines whether the temperature Ts of the AC output control element 26a when the input voltage estimate value Veac of the AC power source 12 during printing of the image forming apparatus 1 is changed to, for example, 150° C. (T top ) and the time t until the AC output control element 26a reaches a temperature at which it is not affected by heat is obtained and recorded as a control table 55 in the RAM 15c.
[0022] <Control table> FIG. 5(b) is a diagram (part 1) showing a control table storing an example of the relationship between the input voltage estimated value, the temperature of the AC output control element, and time in the image forming apparatus according to the first embodiment of the present invention. In the control table 55 shown in FIG. 5(b), the input voltage estimate Veac, the temperature Ts, and the time t are stored in association with each other. Here, the input voltage estimate Veac is the upper limit temperature 150°C (T top ) is an estimated input voltage value of the AC power source 12 during printing, temperature Ts is the temperature of the AC output control element 26a, and time t is the time it takes for the AC output control element 26a to reach a temperature at which it is not affected by heat.
[0023] <Operation of the cooling control unit> (1) The cooling control unit 50a acquires the input voltage estimate value Veac of the AC power supply 12. (2) The cooling control unit 50a obtains from the control table 55 the time t corresponding to the input voltage estimate Veac. (3) The cooling control unit 50a sets the acquired time t as a start time in the timer 15d, and operates the blower 37a when the time set in the timer 15d arrives. Even if the input voltage estimate value Veac of the AC power source 12 is low and the temperature of the AC output control element 26a rises quickly, the blower 37a starts to drive at a time (t 12 ) to delay. On the other hand, when the input voltage estimate value Veac is high and the temperature rise of the AC output control element 26a is slow, the fan start time (t 13 ) can be further delayed. This shortens the time during which noise is generated by the rotation of the blower 37a, and also reduces the power consumption of the blower 37a because the fan operation time is shortened.
[0024] <Flowchart (part 1)> FIG. 6 is a flowchart (part 1) for explaining the operation of the image forming apparatus according to the first embodiment of the present invention. When a print start signal is received from the print engine, the cooling control unit 50a starts operation. In step S10, the cooling control unit 50a 11 ) calls a flowchart of a subroutine for the input voltage estimated value calculation process of step S1000. When the process returns from the input voltage estimated value calculation process of step S1000, the input voltage estimated value Veac is stored in the register of the CPU 15a. In step S20, the cooling control unit 50a determines whether the input voltage estimate value Veac is in a steady state (100V±α (eg, α=5V)). If the input voltage estimate Veac is in a steady state (100 V±α (for example, α=5 V)), the process proceeds to step S30, where the cooling control unit 50a determines the fan start time to be time A, sets the timer 15d to time A, and starts the timer 15d. Here, when the timer 15d has timed the time t=A, it generates an interrupt signal INT and outputs it to the CPU 15a.
[0025] In step S70, when the cooling control unit 50a receives the interrupt signal INT from the timer 15d, it outputs a drive signal (1) to the drive unit 36a. When the drive signal (1) is input, the drive unit 36a applies a high-level signal to the base terminal of the transistor 36 to turn on the collector-emitter, and applies DC 24V to the blower 37a. This operation starts the printing start (t 11 ) the blower 37a is driven with a delay of time A. In step S80, the cooling control unit 50a determines whether or not a print end signal has been received from the print engine, and repeats the process in step S80 until the print end signal is received. When a print end signal is received from the print engine, in step S90, the cooling control unit 50a outputs a stop signal (0) to the drive unit 36a. When the stop signal (0) is input, the drive unit 36a applies a low level signal to the base terminal of the transistor 36 to turn off the collector-emitter and stop the rotation of the blower 37a. This operation stops the blower 37a.
[0026] If the input voltage estimate Veac is not in a steady state (100V±α (for example, α=5V)), the process proceeds to step S40, where the cooling control unit 50a determines whether the input voltage estimate Veac is lower than the steady state (Veac<100V-α). If the input voltage estimate Veac is lower than that in the steady state (Veac<100V-α), in step S50, the cooling control unit 50a advances the fan start time (t=AB) from that in the steady state because the temperature rise of the AC output control element 26a is fast. That is, the cooling control unit 50a determines the fan start time to be time (t=AB), sets the time AB in the timer 15d, starts the timer 15d, and proceeds to step S70. Thereafter, the operation proceeds according to steps S70 to S90. Note that A and B are positive values. When the input voltage estimate value Veac is lower than that in the steady state, the temperature rise of the AC output control element becomes faster, so that the fan start time can be advanced by (t=AB) to operate the blower 37a.
[0027] If the input voltage estimate Veac is not lower than the steady state (Veac<100V-α), i.e., if the input voltage estimate Veac is higher than the steady state, in step S60, the cooling control unit 50a delays the fan start time (t=A+C) from the steady state because the temperature rise of the element 26a becomes gentler. That is, the cooling control unit 50a determines the fan start time to be time (t=A+C), sets the time t=A+C in the timer 15d, starts the timer 15d, and proceeds to step S70. Thereafter, the operation follows steps S70 to S90. Note that A and C are positive values. In this way, when the input voltage estimate Veac is higher than in the steady state, the temperature rise of the AC output control element becomes gradual, so the fan start time can be delayed by (t=A+C) accordingly to operate the blower 37a. This makes it possible to reduce the noise of the blower and the current consumption by controlling the blower drive start time.
[0028] <Subroutine flow chart> FIG. 7 is a flowchart of a subroutine for explaining the operation of the image forming apparatus according to the first embodiment of the present invention. When step S10 of the flowchart shown in FIG. 6 is executed, the cooling control unit 50a calls a flowchart of a subroutine for the input voltage estimated value calculation process of step S1000. When the input voltage estimated value calculation process of step S1000 is called, the process proceeds to step S1010. In step S1010, the cooling control unit 50a acquires the temperature Th0 of the fixing heater 25a (heating unit) from the temperature sensor 40a. In step S1020, the temperature control unit 31a turns on the AC output control element 26a to supply power from the AC power source 12 to the fixing heater 25a via the AC output control element 26a. In step S1030, the temperature rise rate calculation unit 50c sets the timer 15d to 0.1 sec and starts counting down. When an interrupt occurs from the timer 15d 0.1 sec later, the temperature rise rate calculation unit 50c acquires the temperature Th1 of the fixing heater 25a from the temperature sensor 40a. Furthermore, the temperature rise rate calculation unit 50c calculates the temperature rise rate ΔT of the fixing heater 25a = (Th1 - Th0) / 0.1. In step S1040, the cooling control unit 50a estimates an input voltage estimate value Veac related to the input voltage of the AC power supply 12 based on the temperature rise rate ΔT of the fixing heater 25a. Here, the cooling control unit 50a uses the temperature rise rate ΔT of the fixing heater 25a as a key to extract the input voltage estimate value Veac corresponding to the temperature rise rate ΔT from the conversion table 54. The cooling control unit 50a stores the input voltage estimate value Veac in a register of the CPU 15a. As a result, when the process returns from the input voltage estimated value calculation process in step S1000, the input voltage estimated value Veac is stored in the register of the CPU 15a.
[0029] <Conversion table> FIG. 8 is a diagram showing a conversion table that stores an example of the relationship between the temperature rise rate of the fixing heater and the input voltage estimated value in the image forming apparatus according to the first embodiment of the present invention. 8 stores the temperature rise rate ΔT in a predetermined period of time in association with the input voltage estimate value Veac. The conversion table 54 is recorded in the ROM 15b. Here, the temperature rise rate ΔT is the result of dividing the difference between the temperature Th0 of the fixing heater 25a when no power is supplied to the fixing heater 25a and the temperature Th1 of the fixing heater 25a when power is supplied to the fixing heater 25a for a predetermined period of time by a predetermined period of time, for example 0.1 sec. The magnitude of the AC voltage supplied to the primary winding of the transformer 29 depends on the magnitude of the AC voltage, and the input voltage to the A / D1 port fluctuates accordingly. Therefore, the CPU 15a can detect the fluctuation of the AC voltage of the AC power supply 12 from the voltage input to the A / D1 port. The input voltage estimate value Veac is a voltage input from the AC voltage detection circuit 28 to the A / D1 port of the CPU 15a. When creating the conversion table 54, when the AC voltage is increased from 90 V to 110 V in increments of, for example, 0.1 V as a range of AC voltage beyond the steady state, each input voltage input to the A / D1 port is associated with the input voltage estimate value Veac and the temperature rise rate ΔT at that time, and stored in the ROM 15 b as the conversion table 54.
[0030] <Second embodiment> FIG. 9 is a timing chart showing an overview of fan drive time control based on print-OFF time in an image forming apparatus according to a second embodiment of the present invention. In FIG. 9, the previous printing end time is time t 1fe Let the current printing time be time t 21 ~t 2fe The fan operation time is set to time t 2fs ~t 2fe At time t 1fe From time t 21 Print OFF time t off (Print off time). The previous print job ended (time t 1fe ), the supply of power to the fixing heater 25a (heating unit) is terminated, so that no current flows through the AC output control element 26a and the temperature of the element drops. off ) is long, the temperature of the AC output control element 26a drops sufficiently and drops to near room temperature. On the other hand, the previous print end (t 1fe ) to start printing (t 21 ) until the print is turned off (t off When the period is short, the temperature of the AC output control element 26a does not drop completely and remains between room temperature and the upper limit temperature. Last print end (t 1fe ) to start printing (t 21 ) until the print-OFF time t off) is long, the time t at which the temperature of the AC output control element 26a reaches the upper limit in the current printing is off Since the time when the blower 37a for cooling the AC output control element 26a starts to operate (t 2fs ) slows down. On the other hand, the print-off time t off If t is short, the time to reach the upper limit temperature is short, so the fan start time (t 2fs ) to speed up the process.
[0031] <Graph (part 2)> FIG. 10A is a graph (part 2) illustrating an example of the temperature of the AC output control element when the print-OFF time is different in the image forming apparatus according to the second embodiment of the present invention. That is, FIG. 10(a) shows an example of the temperature of the AC output control element when the print-OFF time is different. The cooling control unit 50a controls the temperature Ts of the AC output control element 26a of the image forming apparatus 1 to be lower than a certain temperature (for example, 25° C.) and the upper limit temperature 150° C. (T top ) (for example, 80% of the upper limit temperature of the AC output control element 26a) is grasped and recorded as a control table 56 in the RAM 15c. <Control table (part 2)> FIG. 10(b) is a diagram (part 2) showing a control table storing an example of the relationship between the temperature and time of the AC output control element in the image forming apparatus according to the second embodiment of the present invention. In the control table 56 shown in FIG. 10(b), the temperature T and the time t are stored in association with each other. Here, the temperature Ts is the temperature of the AC output control element 26a, and the time t is the time when the temperature Ts changes from, for example, 25° C. to the upper limit temperature 150° C. (T top ) (for example, 80% of the upper limit temperature of the AC output control element 26a).
[0032] <Control table (part 3)> FIG. 10C is a diagram (part 3) showing a control table that stores an example of the relationship between the print-OFF time and the temperature of the AC output control element in the image forming apparatus according to the second embodiment of the present invention. The cooling control unit 50a is configured to 1fe ) to start printing (t 21 ) until the print is turned off (t off )) and the temperature drop characteristics due to the print OFF time (t off ) is associated with the temperature Ts of the AC output control element 26a and recorded as a control table 57 in the RAM 15c.
[0033] The control table 57 shown in FIG. 10(c) includes the print-OFF time (t off ), and temperature T are stored in association with each other. off ) is the end of the previous print (t 1fe ) to start printing (t 21 ) and temperature Ts is the temperature of AC output control element 26a.
[0034] <Operation of the cooling control unit> (1) When starting printing, the print-off time measurement unit 50b measures the time from the end of the previous print (t 2fe ) to start printing (t 21 ) until the print is turned off (t off )) is measured. (2) The cooling control unit 50a determines the printing OFF time (t off ) is obtained from the control table 57 and estimated. (3) Furthermore, the cooling control unit 50a calculates the upper limit temperature 150° C. (T top ) is obtained from the control table 56 and estimated, and the drive start time (t 2fs ) to delay.
[0035] <Flowchart (part 2)> FIG. 11 is a flowchart (part 2) for explaining the operation of the image forming apparatus according to the second embodiment of the present invention. In the first embodiment, control is performed to set the fan start time by determining whether the input voltage estimate value Veac is in a steady state (100 V±α (for example, α=5 V)). In addition, a feature of the second embodiment is that it measures the print OFF time and determines whether the print OFF time is equal to or longer than t1, thereby controlling to set the fan start time. In addition, since S10, S20, and S70 to S90 in the flowchart shown in FIG. 11 are similar to those in the flowchart shown in FIG. 6, detailed description thereof will be omitted.
[0036] In step S20, the cooling control unit 50a determines whether the input voltage estimate value Veac is in a steady state (100V±α (eg, α=5V)). If the input voltage estimate Veac is in a steady state (100V±α (eg, α=5V)), the process proceeds to step S121, where the cooling control unit 50a determines whether the print-OFF time is equal to or longer than t1. If the print-OFF time is equal to or longer than t1, that is, if the print-OFF time is sufficiently long (equal to or longer than t1) and the element temperature Ts has dropped sufficiently, the process proceeds to step S122, where the cooling control unit 50a determines the fan start time to be time A, sets the timer 15d to time A, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A is a positive value.
[0037] If the print-OFF time is not t1 or more, that is, if the print-OFF time is not long enough (less than t1) and the element temperature Ts has not dropped sufficiently, the process proceeds to step S123, where the cooling control unit 50a determines the fan start time to be time AD, sets the timer 15d to time AD, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and D are positive values.
[0038] If the input voltage estimate Veac is not in a steady state (100V±α (for example, α=5V)), the process proceeds to step S140, where the cooling control unit 50a determines whether the input voltage estimate Veac is lower than the steady state (Veac<100V-α). If the input voltage estimate value Veac is lower than that in the steady state (Veac<100V-α), the process proceeds to step S141, where the cooling control unit 50a determines whether the print-OFF time is equal to or longer than t1. If the print-OFF time is t1 or more, that is, if the print-OFF time is sufficiently long (t1 or more) and the element temperature Ts has dropped sufficiently, the process proceeds to step S142, where the cooling control unit 50a determines the fan start time to be time (t=AB), sets the timer 15d to time (t=AB), starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and B are positive values.
[0039] If the print-OFF time is not t1 or more, that is, if the print-OFF time is not long enough (less than t1) and the element temperature Ts has not dropped sufficiently, the process proceeds to step S143, where the cooling control unit 50a determines the fan start time to be time (t=ABD), sets the timer 15d to time (t=ABD), starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, C, and D are positive values.
[0040] If the input voltage estimate value Veac is higher than that in the steady state (Veac>100V-α), the process proceeds to step S160, where the cooling control unit 50a determines whether the print-OFF time is equal to or longer than t1. If the print-OFF time is equal to or longer than t1, that is, if the print-OFF time is sufficiently long (equal to or longer than t1) and the element temperature Ts has dropped sufficiently, the process proceeds to step S161, where the cooling control unit 50a determines the fan start time to be time (t=A+C), sets the timer 15d to time (t=A+C), starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds according to steps S70 to S90. Note that A and C are positive values. In this way, when the input voltage estimate Veac is higher than the steady state, the printing OFF time is long enough (t1 or more) and the element temperature Ts has dropped sufficiently, the temperature rise of the AC output control element becomes gradual, so the fan start time can be delayed by (t=A+C) accordingly to operate the blower 37a. This makes it possible to reduce the noise of the blower and the current consumption by controlling the blower drive start time.
[0041] If the print-OFF time is not longer than t1, that is, if the print-OFF time is not long enough (less than t1) and the element temperature Ts has not dropped sufficiently, the process proceeds to step S162, where the cooling control unit 50a determines the fan start time to be time (t=A+CD), sets the timer 15d to time (t=A+CD), starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, C, and D are positive values. In this way, when the input voltage estimate Veac is higher than the steady state, the print-off time is not long enough (less than t1) and the element temperature Ts has not dropped sufficiently, the fan start time can be delayed by (t=A+CD) to operate the blower 37a. This makes it possible to reduce the noise of the blower and the current consumption by controlling the blower drive start time.
[0042] <Third embodiment> <Graph (part 3)> FIG. 12A is a graph (part 3) illustrating an example of the temperature of the output control element when the environmental temperature is different in the image forming apparatus according to the third embodiment of the present invention. A temperature sensor 39a for measuring the environmental temperature Tk is provided on the side of the image forming apparatus 1. FIG. 12(a) shows the temperature sensor 39a for measuring the environmental temperature Tk when the apparatus is first started or when the apparatus is left in a sleep / standby state for a long enough period and the temperature of the apparatus drops to the environmental temperature Tk. top ) is grasped and recorded in the RAM 15c as a control table 58.
[0043] <Control table (part 4)> FIG. 12B shows the change in temperature from the environmental temperature Tk to the upper limit temperature T top 13 is a fourth diagram showing a control table storing an example of a time t for the temperature to rise to In the control table 58 shown in FIG. 12B, when the temperature of the image forming apparatus 1 drops to the environmental temperature Tk after the initial startup or after the image forming apparatus 1 has been in a sleep / standby state for a long enough period of time, the temperature T of the AC output control element 26a drops from the environmental temperature Tk to the upper limit temperature 150° C. (T top ) is stored.
[0044] <Operation of the cooling control unit> (1) When starting printing, the cooling control unit 50a obtains the environmental temperature Tk from the temperature sensor 39a. (2) The cooling control unit 50a obtains the temperature Ts of the AC output control element 26a from the temperature sensor 38a. (3) The cooling control unit 50a determines whether or not the temperature Ts of the body (AC output control element 26a) of the image forming apparatus 1 has dropped to the environmental temperature Tk due to a sufficient period of time during initial startup or sleep / standby state. (4) When it is determined that the temperature Ts has dropped to the environmental temperature Tk, the cooling control unit 50a top ) is obtained from the control table 58 and estimated. (5) The cooling control unit 50a adjusts the blower 37a drive start time (t 2fs ) to delay. Thereby, when the temperature Ts of the AC output control element 26a is lower than the environmental temperature Tk, the cooling control unit 50a can further delay the drive start time of the blower 37a.
[0045] <Flowchart (part 3)> FIG. 13 is a flowchart (part 3) for explaining the operation of the image forming apparatus according to the third embodiment of the present invention. In the first embodiment, the fan start time is controlled by determining whether the input voltage estimate value Veac is in a steady state (100 V±α (for example, α=5 V)). In addition, the third embodiment is characterized in that it includes a temperature sensor 39a that measures the environmental temperature, and the cooling control unit 50a further delays the drive start time of the blower 37a when the environmental temperature measured by the temperature sensor 39a is lower than the steady state temperature Tk. In addition, since S10, S20, and S70 to S90 in the flowchart shown in FIG. 13 are similar to those in the flowchart shown in FIG. 6, detailed description thereof will be omitted.
[0046] In step S20, the cooling control unit 50a determines whether the input voltage estimate value Veac is in a steady state (100V±α (eg, α=5V)). If the input voltage estimate Veac is in a steady state (100V±α (eg, α=5V)), the process proceeds to step S221, where the cooling control unit 50a determines whether the environmental temperature Tk is within 25±α (eg, α=5° C.). If the environmental temperature Tk is within 25±α, the process proceeds to step S222, where the cooling control unit 50a determines the fan start time to be time A, sets the timer 15d to time A, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A is a positive value.
[0047] If the environmental temperature Tk is not within 25±α, that is, if the environmental temperature Tk is 25-α or more, the process proceeds to step S223, where the cooling control unit 50a judges whether the environmental temperature Tk is 25-α or less. If the environmental temperature Tk is 25-α or less, the process proceeds to step S224, where the cooling control unit 50a determines the fan start time to be time A+E, sets the timer 15d to time A+E, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and E are positive values. When the environmental temperature Tk is low (25° C.-α° C. or lower), the temperature rise time of the AC output control element 26a becomes long, so that the fan start time can be delayed by time E before the fan is operated.
[0048] If the environmental temperature Tk is not equal to or lower than 25-α, the process proceeds to step S225, where the cooling control unit 50a determines the fan start time to be time AF, sets the timer 15d to time AF, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and F are positive values. When the environmental temperature Tk is high, the time it takes for the element to reach the set temperature is shortened, so that the fan can be operated earlier by the time F.
[0049] If the input voltage estimate Veac is not in the steady state (100V±α (e.g., α=5V)), that is, if the input voltage estimate Veac is outside the range of the steady state (100V±α (e.g., α=5V)), the process proceeds to step S240, and the cooling control unit 50a determines whether the input voltage estimate Veac is lower than the steady state (Veac<100V-α). If the input voltage estimate Veac is lower than that in the steady state (Veac<100V-α), the process proceeds to step S241, where the cooling control unit 50a determines whether the environmental temperature Tk is within 25±α (eg, α=5° C.). If the environmental temperature Tk is within 25±α, the process proceeds to step S242, where the cooling control unit 50a determines the fan start time to be time AB, sets the time AB in the timer 15d, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and B are positive values.
[0050] If the environmental temperature Tk is not within 25±α, the process proceeds to step S243, where the cooling control unit 50a judges whether the environmental temperature Tk is 25-α or less. If the environmental temperature Tk is 25-α or less, the process proceeds to step S244, where the cooling control unit 50a determines the fan start time to be time A-B+E, sets the timer 15d to time A-B+E, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, B, and E are positive values. When the environmental temperature Tk is low (25° C.-α° C. or lower), the temperature rise time of the AC output control element 26a becomes long, so that the fan start time can be delayed by time E before the fan is operated.
[0051] If the environmental temperature Tk is not equal to or less than 25-α, that is, if the environmental temperature Tk is equal to or greater than 25-α, the process proceeds to step S245, where the cooling control unit 50a determines the fan start time to be time ABF, sets the timer 15d to time ABF, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, B, and F are positive values. When the environmental temperature Tk is high, the time it takes for the element to reach the set temperature is shortened, so that the fan can be operated earlier by the time F.
[0052] If the input voltage estimate Veac is not lower than the steady state (Veac<100V-α), that is, if the input voltage estimate Veac is higher than the steady state (Veac>100V-α), the process proceeds to step S260, and the cooling control unit 50a determines whether the environmental temperature Tk is within 25±α (for example, α=5°C). If the environmental temperature Tk is within 25±α, the process proceeds to step S261, where the cooling control unit 50a determines the fan start time to be time A+C, sets the timer 15d to time A+C, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A and B are positive values.
[0053] If the environmental temperature Tk is not within 25±α, the process proceeds to step S262, where the cooling control unit 50a determines whether the environmental temperature Tk is equal to or lower than 25−α. If the environmental temperature Tk is equal to or lower than 25-α, the process proceeds to step S263, where the cooling control unit 50a determines the fan start time to be time A+C+E, sets the timer 15d to time A+C+E, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, C, and E are positive values. When the environmental temperature Tk is low (25°C-α°C or less), it takes a long time for the AC output control element 26a to rise to temperature, so the fan start time can be delayed by the time E to operate the fan. This makes it possible to reduce the noise of the blower and the current consumption by controlling the blower drive start time.
[0054] If the environmental temperature Tk is not equal to or less than 25-α, that is, if the environmental temperature Tk is equal to or greater than 25-α, the process proceeds to step S264, where the cooling control unit 50a determines the fan start time to be time A+CF, sets the timer 15d to time A+CF, starts the timer 15d, and proceeds to step S70. Thereafter, the process proceeds to steps S70 to S90. Note that A, C, and F are positive values. When the environmental temperature Tk is high, the time it takes for the element to reach the set temperature is shortened, so that the fan can be operated earlier by the time F.
[0055] <Summary of the functions and effects of the embodiment> <First aspect> The cooling device for an AC output control element of this embodiment is a cooling device for an AC output control element 26a including a heating unit, a temperature control unit 51a that controls the heating temperature by controlling the power supplied from the AC power source 12 to the heating unit using the AC output control element 26a, a blower 37a that suppresses a rise in temperature of the AC output control element 26a, and a drive unit 36a that drives the blower 37a, and is characterized in that the cooling control unit 50a includes an on / off control of the drive unit 36a to maintain the temperature of the AC output control element 26a within an allowable temperature range, a temperature sensor 38a that measures the temperature of the heating unit, a temperature rise rate calculation unit 50c that calculates a temperature rise rate ΔT in a predetermined period based on the temperature of the heating unit, and an input voltage estimation unit 50d that estimates an input voltage estimate value Veac related to the input voltage of the AC power source 12 based on the temperature rise rate ΔT, and the cooling control unit 50a determines a drive start time of the blower 37a based on the input voltage estimate value Veac. According to this embodiment, the cooling control unit 50a determines the drive start time t of the blower 37a based on the input voltage estimate value Veac of the AC power supply 12. 1fs By determining the time when the blower starts to operate, the noise of the blower can be reduced and the current consumption can be reduced.
[0056] <Second aspect> The cooling control unit 50a of this embodiment is characterized in that, when the input voltage estimate value Veac of the AC power supply 12 is higher than that in the steady state, the driving start time of the blower 37a is delayed. According to this embodiment, when the input voltage estimated value Veac of the AC power supply 12 is higher than that in the steady state, the cooling control unit 50a delays the drive start time of the blower 37a by (t=A+C), thereby making it possible to reduce the noise of the blower 37a and the current consumption.
[0057] <Third aspect> In the image forming apparatus 1 of this embodiment, the printing off time t off The cooling control unit 50a is provided with a printing-off time measurement unit 50b that measures the printing-off time t off The time to start driving the blower 37a is determined based on the above. According to this embodiment, the cooling control unit 50a controls the printing off time t off By determining the drive start time of the blower 37a based on the above, the drive start time of the blower 37a can be controlled to reduce the noise of the blower 37a and the current consumption. For example, the print-off time t off Even if the time is short and preheating remains, the blower 37a can be operated at the optimum start timing, reducing noise and current consumption.
[0058] <Fourth aspect> The image forming apparatus 1 of this embodiment is equipped with a temperature sensor 39a that measures the environmental temperature Tk, and the cooling control unit 50a is characterized in that when the environmental temperature Tk measured by the temperature sensor 39a is lower than the steady-state temperature, the cooling control unit 50a further delays the start time of driving the blower 37a. According to this embodiment, when the environmental temperature Tk measured by the temperature sensor 39a is lower than the temperature in the steady state, the cooling control unit 50a can further delay the drive start time of the blower 37a.
[0059] <Fifth aspect> The image forming apparatus 1 of this embodiment is equipped with a temperature sensor 38a that measures the temperature Ts of the AC output control element 26a and a temperature sensor 39a that measures the external environmental temperature Tk, and is characterized in that the cooling control unit 50a further delays the start time of driving the blower 37a when the temperature Ts of the AC output control element 26a is lower than the environmental temperature Tk. According to this embodiment, when the temperature Ts of the AC output control element 26a is lower than the environmental temperature Tk, the cooling control unit 50a can further delay the drive start time of the blower 37a.
[0060] <Sixth aspect> The image forming apparatus 1 of this embodiment is characterized in that it includes the cooling device for the AC output control element according to any one of the first to fifth embodiments, and the heating section is a fixing heater 25a. According to this embodiment, the cooling control unit 50a determines the drive start time t of the blower 37a based on the input voltage estimate value Veac of the AC power supply 12. 1fsBy determining the time when the blower starts to operate, the noise of the blower can be reduced and the current consumption can be reduced. [Explanation of symbols]
[0061] 5...image forming section, 6...photosensitive drum, 7...developing section, 8...conveyor belt, 9...fixing section, 12...AC power supply, 14...control board, 15a...CPU, 15b...ROM, 15c...RAM, 15d...timer, 25...halogen heater, 25a...fixing heater (heating section), 26...TRIAC, 26a...AC output control element, 27...TRIAC control signal, 31a...temperature control section, 35a...DC power supply, 36a...driving section, 37a...blower, 38a...temperature sensor, 39a...temperature sensor, 40a...temperature sensor, 50a...cooling control section, 50b...print off time measuring section, 50c...temperature rise rate calculation section, 50d...input voltage estimation section, 51a...temperature control section, 55...control table, 56...control table, 57...control table, 58...control table [Prior art documents] [Patent documents]
[0062] [Patent Document 1] JP 2009-180909 A
Claims
1. A heating unit; a temperature control unit that controls the power supplied from an AC power source to the heating unit using an AC output control element to control the heating temperature; a blower for suppressing an increase in temperature of the AC output control element; A cooling device for an AC output control element comprising: a cooling control unit that controls the driving unit to be turned on and off in order to maintain the temperature of the AC output control element within an allowable temperature range; A temperature sensor for measuring a temperature of the heating unit; a temperature rise rate calculation unit that calculates a temperature rise rate in a predetermined period based on the temperature of the heating unit; an input voltage estimation unit that estimates an input voltage estimation value related to an input voltage of the AC power supply based on the temperature rise rate, The cooling device for an AC output control element, wherein the cooling control unit determines a drive start time of the blower based on the input voltage estimate value.
2. 2. The cooling device for an AC output control element according to claim 1, wherein the cooling control unit delays the drive start time of the blower when the input voltage estimate value of the AC power supply is higher than that in a steady state.
3. a print-off time measuring unit for measuring a print-off time from the end of a previous print to the start of a current print, 2. The cooling device for an AC output control element according to claim 1, wherein the cooling control unit determines the drive start time of the blower based on the printing off time.
4. An environmental temperature sensor that measures an external environmental temperature; 2. The cooling device for an AC output control element according to claim 1, wherein the cooling control unit further delays the drive start time of the blower when the environmental temperature is lower than a steady-state temperature.
5. a temperature sensor for measuring a temperature of the AC output control element; An environmental temperature sensor that measures an external environmental temperature; 2. The cooling device for an AC output control element according to claim 1, wherein the cooling control unit further delays the drive start time of the blower when the temperature of the AC output control element is lower than the environmental temperature.
6. A cooling device for an AC output control element according to any one of claims 1 to 5, The image forming apparatus according to claim 1, wherein the heating section is a fixing heater.
Citation Information
Patent Citations
Image forming device
JP2009180909A