JP2005076540A - Fan control device - Google Patents

Abstract

A 1 / f fluctuation characteristic ROM 3 instructs generation of a pulse train, and a fan drive pulse generator 5 outputs the pulse train based on an instruction of the fan 1 / f fluctuation characteristic ROM 3.
[Effect] 1 / f fluctuation characteristic The pulse interval of the fan drive signal 7a is controlled in accordance with the data obtained by converting the 1 / f fluctuation characteristic stored in the ROM 3 into a pulse interval, and thereby the air volume of the heat radiating fan 8 is reduced by 1 / f fluctuation. It can be controlled by characteristics. In addition, a predetermined DC voltage may be applied, and a multistage voltage control circuit is not necessary. Furthermore, since the entire fan control device can be configured with a digital circuit, it can be made into an ASIC (Application Specific IC), and the hardware configuration can be greatly reduced in cost.
[Selection] Figure 1

Description

  The present invention relates to a fan control device that prevents noise from being generated by a heat radiating fan such as a printing device.

  In an electrophotographic printing apparatus or the like, a toner image is formed on a photosensitive drum, the toner image is transferred onto a printing medium, the printing medium onto which the toner image has been transferred is fixed with a heat roller, and an output image is transferred. It has gained. In such a printing apparatus, accurate temperature control of the heat roller is required to improve image quality. For this reason, a heat dissipating fan for discharging heat generated inside the apparatus is arranged. Wind noise is generated from this heat radiating fan.

  This wind noise often becomes annoying noise. However, it is impossible to completely remove this wind noise. Therefore, in order to prevent the wind noise from becoming annoying noise, by controlling the voltage applied to the heat radiating fan with the periodic component of 1 / f fluctuation, the wind noise is reduced to 1 / f fluctuation so as not to become annoying noise. The invention to make is disclosed (for example, Patent Document 1).

  Here, 1 / f fluctuation is a natural occurrence such as a breeze, and is usually expressed as a change that does not have a regular period or a temporal fluctuation that exists around a certain value. ing. That is, this 1 / f fluctuation is considered to be a fluctuation in which many people feel comfortable like a breeze.

Japanese Patent Laid-Open No. 9-212044 (summary and paragraph 0016)

In the above conventional technique, in order to generate wind noise with 1 / f fluctuation, the voltage applied to the heat radiating fan is controlled with a periodic component of 1 / f fluctuation. For this reason, a multi-stage voltage control circuit is required, and the cost of hardware increases. Even when a plurality of control fans are arranged, it is difficult to maintain the temperature inside the apparatus at a predetermined temperature because the control is performed only with 1 / f fluctuation.
It is an object of the present invention to solve this problem and to obtain a low-cost and high-performance fan control device.

The present invention adopts the following configuration in order to solve the above points.
<Configuration 1>
A fan control device that changes an air volume with time according to a predetermined control characteristic, a pulse signal instruction unit that instructs generation of a pulse train that approximates the control characteristic, and the pulse train based on an instruction of the pulse signal instruction unit And a pulse signal output unit for outputting the fan control device.

<Configuration 2>
In the fan control device according to Configuration 1, the pulse signal instructing unit stores each pulse interval in the pulse train so as to approximate the control characteristic by a change in the pulse interval of the pulse train having the same pulse width. The pulse signal output unit includes data reading means for reading the pulse interval from the storage unit, and pulse generation means for generating the pulse train based on the pulse interval read by the data reading means. Features a fan control device.

<Configuration 3>
In the fan control device according to Configuration 1, the pulse signal instructing unit is configured to approximate the control characteristics with changes in pulse intervals of pulse trains having different pulse widths, and the individual pulse widths and individual pulses in the pulse train. A storage unit for storing an interval; and the pulse signal output unit is based on the data reading unit for reading the pulse width and the pulse interval from the storage unit, and the pulse width and the pulse interval read by the data reading unit. And a fan control device comprising on / off control means for generating the pulse train.

<Configuration 4>
In the fan control device according to Configuration 2, the internal temperature detection means for detecting the internal temperature, the correction value calculation means for calculating the air flow correction value based on the change in the internal temperature, and the data reading means And a correction value adding means for outputting a pulse interval obtained by adding the airflow correction value to the read pulse interval to the pulse width generating means.

<Configuration 5>
In the fan control device according to Configuration 2, the pulse signal output from the pulse signal output unit and a pulse train having the same pulse width and pulse interval are received, and the pulse signal is output from at least one output end of a plurality of output ends. The apparatus further comprises output selection means for outputting a pulse train output from the output section and outputting a pulse train having the same pulse width and pulse interval from the remaining output terminals, and supplying the output of the output selection means to a plurality of heat radiating fans. A fan control device.

<Configuration 6>
In the fan control device according to any one of Configurations 1 to 3, a plurality of power supply voltages having different voltage values to be supplied to the heat radiating fan are received, and a predetermined voltage value is selected to the heat radiating fan. A fan control device further comprising power supply voltage selection means for supply.

<Configuration 7>
7. The fan control device according to any one of configurations 1 to 6, wherein the control characteristic is air volume control based on a 1 / f fluctuation cycle component.

  By providing a pulse signal instruction unit that instructs generation of a pulse train that approximates a predetermined control characteristic, and a pulse signal output unit that outputs the pulse train based on an instruction from the pulse signal instruction unit, the entire fan control device is a digital circuit. The hardware configuration can be greatly reduced, and the hardware configuration can be greatly reduced. Furthermore, by making the predetermined control characteristic 1 / f fluctuation characteristic, there is an effect that discomfort can be eliminated from the wind noise of the heat radiating fan.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Configuration of Example 1>
FIG. 1 is a block diagram of the fan control device according to the first embodiment.
As shown in the figure, the fan control apparatus according to the first embodiment includes a main controller 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 3, a RAM 4, a fan drive pulse generator 5, a common bus 6, and a fan drive. Part 7.

The main control unit 1 is a CPU (Central Processing Control Unit) that is connected to the common bus 6 and controls the entire apparatus.
The control ROM 2 is a read-only memory that is connected to the common bus 6 and stores programs and data necessary for the main control unit 1 to control the entire apparatus.
The 1 / f fluctuation characteristic ROM 3 is connected to the common bus 6, and the 1 / f fluctuation characteristic, which is a control characteristic of the air flow control of the heat radiating fan 8, is approximated by pulse trains having equal pulse widths and different intervals. This read-only memory stores the interval data.
An address corresponding to each pulse is set in accordance with the order of the pulse train, and the pulse interval from the immediately preceding pulse is converted into the number of system clocks and stored in the address.

The RAM 4 is a random access memory that is connected to the common bus 6 and stores temporary data necessary for various controls by the main control unit 1.
The fan drive pulse generator 5 is connected to the common bus 6, reads the pulse train interval data stored in the 1 / f fluctuation characteristic ROM 3, generates a pulse train, and sends the voltage application command signal 5 d to the fan driver 7. This is the part to send to. It has an interval data read unit 5-1, a pulse interval counter 5-2, and a constant width pulse generation unit 5-3.

  The interval data read unit 5-1 sends the storage address 5a of the data to be read out to the 1 / f fluctuation characteristic ROM 3, and represents the interval of the pulses stored in the storage address 5a from the 1 / f fluctuation characteristic ROM 3. The interval data 5b is read and set in the pulse interval counter 5-2. The interval data 5b is represented by the number of system clocks (an example).

The pulse interval counter 5-2 is a timer counter that subtracts the number of set clocks (pulse interval) set by the interval data read unit 5-1 every elapse of the system clock cycle. The pulse interval is monitored based on the set number of clocks (count value), and when the count value becomes 0, the trigger signal 5c is sent to the interval data read unit 5-1 and the constant width pulse generation unit 5-3. Part.
When receiving the trigger signal 5 c, the constant width pulse generating unit 5-3 is a part that sends a pulse signal (voltage application command signal 5 d) having the same pulse width to the fan driving unit 7 in synchronization with the trigger signal 5 c.

The fan drive unit 7 is a part that drives the fan by sending the fan drive signal 7a to the heat dissipation fan 8 for a predetermined time based on the voltage application command signal 5d received from the fan drive pulse generation unit 5.
The common bus 6 is a signal line that connects the main control unit 1, the control ROM 2, the 1 / f fluctuation characteristic ROM 3, the RAM 4, and the fan drive pulse generation unit 5 to form a signal transmission path.

<Operation of Example 1>
FIG. 2 is an operation explanatory diagram of the first embodiment.
(A) is a figure which shows the air volume change of a thermal radiation fan, a vertical axis | shaft represents the air volume of a thermal radiation fan, and the horizontal axis represents time. The curve shown in this figure represents the air volume of the radiating fan based on the 1 / f fluctuation cycle component used in this embodiment. When the air volume of the heat dissipating fan is controlled as shown in this figure, the wind noise generated from the heat dissipating fan is similarly changed. Therefore, even if this wind noise is heard, no discomfort is felt.
(B) is the elements on larger scale of (a), (c) is a figure showing the control sequence of the pulse train (voltage application command signal 5d (FIG. 1)) for performing the air volume control shown in (b). is there.

The operation of the first embodiment will be described with reference to (c).
When the count value of the pulse interval counter 5-2 (FIG. 1) becomes 0 at time t1, the trigger signal 5c (FIG. 1) is changed to a constant width pulse generator 5-3 (FIG. 1) and an interval data read unit 5-1 (FIG. 1). 1).
When the constant width pulse generator 5-3 (FIG. 1) receives the trigger signal 5c, the fan generates an Nth pulse (voltage application command signal 5d (FIG. 1)) having the same pulse width in synchronization with the trigger signal 5c. It is sent to the drive unit 7 (FIG. 1). When the fan drive unit 7 (FIG. 1) accepts the Nth pulse, it sends a fan drive signal 7a (FIG. 1) to the heat dissipation fan 8 (FIG. 1) for a predetermined time to drive the heat dissipation fan 8 (FIG. 1). .

  When the interval data read unit 5-1 (FIG. 1) receives the trigger signal 5c (FIG. 1), data corresponding to the (N + 1) th pulse is stored toward the 1 / f fluctuation characteristic ROM 3 (FIG. 1). 1 represents the interval between pulses stored in the storage address 5a from the 1 / f fluctuation characteristic ROM 3 (FIG. 1) (interval between the Nth pulse and the N + 1th pulse). The interval data 5b (FIG. 1) is read. The pulse interval is set in the pulse interval counter 5-2 (FIG. 1) as a count value.

When the count value of the pulse interval counter 5-2 (FIG. 1) becomes 0 at time t2, the trigger signal 5c (FIG. 1) is changed to a constant width pulse generator 5-3 (FIG. 1) and an interval data read unit 5-1 (FIG. 1). 1).
When the constant width pulse generator 5-3 (FIG. 1) receives the trigger signal 5c, the N + 1-th pulse (voltage application command signal 5d (FIG. 1)) having the same pulse width is synchronized with the trigger signal 5c. It is sent to the drive unit 7 (FIG. 1). When the fan driving unit 7 (FIG. 1) receives the (N + 1) th pulse, the fan driving unit 7 (FIG. 1) sends a fan driving signal 7a (FIG. 1) for a predetermined time to drive the heat radiating fan 8 (FIG. 1). .

  When the interval data read unit 5-1 (FIG. 1) receives the trigger signal 5c, the interval data read unit 5-1 (FIG. 1) stores the data corresponding to the (N + 2) th pulse toward the 1 / f fluctuation characteristic ROM 3 (FIG. 1). (FIG. 1) is transmitted and represents the interval between pulses stored in the storage address 5a (FIG. 1) from the 1 / f fluctuation characteristic ROM 3 (FIG. 1) (interval between the (N + 1) th pulse and the (N + 2) th pulse). The interval data 5b (FIG. 1) is read. This pulse interval is set in the pulse interval counter 5-2 (FIG. 1) as a count value equal to the number of clocks.

When the count value of the pulse interval counter 5-2 (FIG. 1) becomes 0 at time t3, the trigger signal 5c (FIG. 1) is changed to a constant width pulse generator 5-3 (FIG. 1) and an interval data read unit 5-1 (FIG. 1). 1).
When the constant width pulse generator 5-3 (FIG. 1) receives the trigger signal 5c (FIG. 1), the N + 2th pulse (voltage application command signal 5d (FIG. 1) having the same pulse width is synchronized with the trigger signal 5c. )) Is sent to the fan drive unit 7 (FIG. 1). When the fan drive unit 7 (FIG. 1) accepts the (N + 2) th pulse, it sends a fan drive signal 7a (FIG. 1) to the heat dissipation fan 8 (FIG. 1) for a predetermined time to drive the heat dissipation fan 8 (FIG. 1). .

When the interval data read unit 5-1 (FIG. 1) receives the trigger signal 5c (FIG. 1), the data corresponding to the (N + 3) th pulse is stored toward the 1 / f fluctuation characteristic ROM 3 (FIG. 1). Storage address 5a (FIG. 1) is transmitted, and the interval between the pulses stored in the storage address 5a (FIG. 1) from the 1 / f fluctuation characteristic ROM 3 (FIG. 1) (N + 2 pulse and N + 3 pulse) The interval data 5b (Fig. 1) representing the interval) is read. The pulse interval is set in the pulse interval counter 5-2 (FIG. 1) as a count value.
Thereafter, the same operation is repeated.

The following points should be noted regarding the operation described above.
The fan drive unit 7 (FIG. 1) drives the heat radiating fan 8 (FIG. 1) for a predetermined time each time the pulse train (voltage application command signal 5d (FIG. 1)) in (c) is received. That is, if the interval between the pulse trains in (c) is shortened, the airflow of the heat dissipating fan is increased. Conversely, if the interval between the pulse trains is increased, the airflow of the heat dissipating fan is decreased. That is, by changing the pulse interval of the pulse train, the fan air volume can be approximated to a periodic component of 1 / f fluctuation.

In the above description, the 1 / f fluctuation characteristic ROM 3 (FIG. 1) corresponds to the pulse signal instruction section in the claims.
The fan drive pulse generator 5 (FIG. 1) corresponds to the pulse signal output unit in the claims.

<Effect of Example 1>
As described above, according to the present embodiment, the pulse interval of the fan drive signal 7a is controlled according to the data obtained by converting the 1 / f fluctuation characteristic stored in the 1 / f fluctuation characteristic ROM 3 (FIG. 1) into the pulse interval, Thereby, the air volume of the heat radiating fan 8 can be controlled by the 1 / f fluctuation characteristic. In this embodiment, a predetermined DC voltage may be applied, and a multistage voltage control circuit is not necessary. Furthermore, since the entire fan control device can be configured with a digital circuit, it can be made into an ASIC (Application Specific IC), and the hardware configuration can be greatly reduced in cost.

<Configuration of Example 2>
FIG. 3 is a block diagram of the fan control device according to the second embodiment.
As shown in the figure, the fan control device according to the second embodiment includes a main control unit 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 13, a RAM 4, a fan drive pulse generation unit 15, a common bus 6, and a fan drive. Part 7.

The 1 / f fluctuation characteristic ROM 13 is connected to the common bus 6 and is used for approximating the 1 / f fluctuation characteristic, which is a control characteristic of the air flow control of the heat radiating fan 8, with pulse widths and pulse intervals different from each other. This is a read-only memory for storing pulse train generation data.
One address corresponding to each time the pulse is turned on or off is set in the inside, and the interval until the next change is set every time the pulse is turned on or off in the address. 15b is stored as a value converted to the system clock.

  The fan drive pulse generator 15 is connected to the common bus 6 and reads the interval data in the pulse train stored in the 1 / f fluctuation characteristic ROM 13, generates a pulse train, and drives the fan as the voltage application command signal 15d. This is a part to be sent to the part 7. It includes an interval data read unit 15-1, a pulse interval counter 15-2, and an ON / OFF control unit 15-3.

  The interval data read unit 15-1 sends a storage address 15a of data to be read to the 1 / f fluctuation characteristic ROM 13, and reads the interval data 15b stored in the storage address 15a from the 1 / f fluctuation characteristic ROM 13. This is the part set in the pulse interval counter 15-2. The interval data 15b is represented by the number of system clocks (an example).

  The pulse interval counter 15-2 is a timer counter that subtracts the number of set clocks (pulse interval) set by the interval data read unit 15-1 every elapse of the system clock period. Based on the set number of clocks (count value), the interval of turning on or off in the pulse train is monitored, and when the count value becomes 0, the trigger signal 15c is sent to the interval data read unit 15-1 and the ON / OFF control unit. It is also a part sent to 15-3.

When the ON / OFF control unit 15-3 receives the trigger signal 15c, the ON / OFF control unit 15-3 generates a pulse train by changing the pulse to ON or OFF in synchronization with the trigger signal 15c. Further, this pulse train (voltage application command signal 15 d) is a part for sending out to the fan drive unit 7.
Other constituent elements are the same as those in the first embodiment, and the description thereof is omitted.

<Operation of Example 2>
FIG. 4 is an operation explanatory diagram of the second embodiment.
(A) is a figure which shows the air volume change of a thermal radiation fan, the vertical axis | shaft represents the air volume of a thermal radiation fan, and the horizontal axis represents time. The curve shown in this figure represents the air volume of the radiating fan based on the 1 / f fluctuation cycle component used in this embodiment. When the air volume of the heat dissipating fan is controlled as shown in this figure, the wind noise generated from the heat dissipating fan is similarly changed. Therefore, even if this wind noise is heard, no discomfort is felt.
(B) is the elements on larger scale of (a), (c) is a figure showing the control sequence of the pulse train (voltage application command signal 15d (FIG. 3)) for performing the air volume control shown in (b). is there.

The operation of the second embodiment will be described with reference to (c).
When the count value of the pulse interval counter 15-2 (FIG. 3) becomes 0 at time t1, the trigger signal 15c (FIG. 3) is turned on by the ON / OFF control unit 15-3 (FIG. 3) and the interval data read unit 15-1 (FIG. 3). 3).
Upon receiving the trigger signal 15c, the ON / OFF control unit 15-3 (FIG. 3) turns on the pulse in synchronization with the trigger signal 15c, and the voltage application command signal 15d (FIG. 3) turns from off to on. The change (“change N”) is sent to the fan drive unit 7 (FIG. 3). When the fan driving unit 7 (FIG. 3) receives “change N”, the fan driving unit 7 (FIG. 3) sends a fan driving signal 7a (FIG. 3) to start driving the heat radiating fan 8 (FIG. 3).

  When the interval data read unit 15-1 (FIG. 3) receives the trigger signal 15c (FIG. 3), data corresponding to “change N + 1” is stored toward the 1 / f fluctuation characteristic ROM 13 (FIG. 3). Interval data 15b (FIG. 3) representing the interval between “change N” and “change N + 1” stored in the storage address 15a (FIG. 3) from the 1 / f fluctuation characteristic ROM 13 (FIG. 3). 3) is read out. The interval between “change N” and “change N + 1” is set in the pulse interval counter 15-2 (FIG. 3) as a count value.

When the count value of the pulse interval counter 15-2 (FIG. 3) becomes 0 at time t2, the trigger signal 15c (FIG. 3) is changed to the ON / OFF control unit 15-3 (FIG. 3) and the interval data read unit 15-1 (FIG. 3). 3).
Upon receiving the trigger signal 15c (FIG. 3), the ON / OFF control unit 15-3 (FIG. 3) turns off the pulse in synchronization with the trigger signal 15c (FIG. 3), and applies the voltage application command signal 15d (FIG. 3). ) Is sent from the on state to the off state (“change N + 1”) to the fan drive unit 7 (FIG. 3). When the fan driving unit 7 (FIG. 3) receives “change N + 1”, the fan driving unit 7 (FIG. 3) stops sending the fan driving signal 7a to the heat radiating fan 8 (FIG. 3) and stops driving the heat radiating fan 8 (FIG. 3).

  When the interval data read unit 15-1 (FIG. 3) receives the trigger signal 15c (FIG. 3), data corresponding to “change N + 2” is stored toward the 1 / f fluctuation characteristic ROM 13 (FIG. 3). Interval indicating the interval between “change N + 1” and “change N + 2” stored in the storage address 15a (FIG. 3) from the 1 / f fluctuation characteristic ROM 13 (FIG. 3). Data 15b (FIG. 3) is read. The interval between this “change N + 1” and “change N + 2” is set in the pulse interval counter 15-2 (FIG. 3) as a count value.

When the count value of the pulse interval counter 15-2 (FIG. 3) becomes 0 at time t3, the trigger signal 15c (FIG. 3) is turned on by the ON / OFF control unit 15-3 (FIG. 3) and the interval data read unit 15-1 (FIG. 3). 3).
Upon receiving the trigger signal 15c (FIG. 3), the ON / OFF control unit 15-3 (FIG. 3) turns on the pulse in synchronization with the trigger signal 15c (FIG. 3), and the voltage application command signal 15d (FIG. 3). ) Is turned on from off ("change N + 2") is sent to the fan drive unit 7 (FIG. 3). When the fan drive unit 7 (FIG. 3) accepts “change N + 2”, it sends a fan drive signal 7a (FIG. 3) to the heat dissipation fan 8 (FIG. 3), and starts driving the heat dissipation fan 8 (FIG. 3).

When the interval data read unit 15-1 (FIG. 3) receives the trigger signal 15c (FIG. 3), data corresponding to “change N + 3” is stored toward the 1 / f fluctuation characteristic ROM 13 (FIG. 3). Interval indicating the interval between “change N + 2” and “change N + 3” stored in the storage address 15a (FIG. 3) from the 1 / f fluctuation characteristic ROM 13 (FIG. 3). Data 15b (FIG. 3) is read. The interval between this “change N + 2” and “change N + 3” is set in the pulse interval counter 15-2 (FIG. 3) as a count value.
Thereafter, the same operation is repeated.

The following points should be noted regarding the operation described above.
The fan drive unit 7 (FIG. 3) starts driving the heat radiating fan 8 (FIG. 3) every time it receives the ON / OFF change of the pulse in FIG. 3C (voltage application command signal 15d (FIG. 3)). Or stop. That is, in (c), when the ratio of the pulse-on time to the pulse-off time is large within a predetermined time, the airflow of the heat dissipating fan is large. Conversely, when the ratio is small, the airflow of the heat dissipating fan is Get smaller. That is, it can be approximated to a periodic component of 1 / f fluctuation by pulse trains having different pulse widths and intervals.

<Effect of Example 2>
As described above, since the 1 / f fluctuation periodic component is approximated not only by the pulse interval but also by the pulse width, in addition to the effects of the first embodiment, the data capacity of the 1 / f fluctuation characteristic ROM 13 is reduced. The effect that it can be obtained.

<Configuration of Example 3>
FIG. 5 is a block diagram of the fan control device according to the third embodiment.
As shown in the figure, the fan control device according to the third embodiment includes a main controller 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 23, a RAM 4, a fan drive pulse generator 25, a common bus 6, and a fan drive. Part 7.

  The 1 / f fluctuation characteristic ROM 23 is connected to the common bus 6 and is a pulse train generation data for approximating the 1 / f fluctuation characteristic, which is a control characteristic of the air flow control of the heat radiating fan 8, with pulse widths and intervals different from each other. Is a read-only memory in which is stored.

  Inside the address, one address is set every time the pulse is turned on or off, and within the address, the interval between “change N” and “change N + 1” (the number of system clocks obtained this time). Difference between “change N + 1” and “change N−1” and “change N” (the previous number of system clocks, and hereinafter referred to as “change N” count value) (Hereinafter referred to as a difference value of “change N + 1”) is stored as the interval data 25b.

  Therefore, the current set value (count value of “change N + 1”) is obtained by adding the interval data 25b (difference value of “change N + 1”) read this time to the previous set value (count value of “change N”). Will be obtained.

  The fan drive pulse generator 25 is connected to the common bus 6 and reads the pulse train interval data stored in the 1 / f fluctuation characteristic ROM 23 to generate a pulse train, which is used as the voltage application command signal 25d. The interval data read unit 25-1, the adder 25-2, the pulse interval register 25-3, the pulse interval counter 15-2, and the ON / OFF control unit 15-3 are included therein. And have.

  The interval data read unit 25-1 sends a storage address 25a of data to be read out to the 1 / f fluctuation characteristic ROM 23, and reads out the interval data 25b stored in the storage address 25a from the 1 / f fluctuation characteristic ROM 23. This is the part that is sent to the adder 25-2.

  The adder 25-2 adds the interval data 25b (difference value of “change N + 1”) read this time to the previous set value (count value of “change N”) set in the pulse interval register 25-3. Thus, the current set value (the count value of “change N + 1”) is obtained, and the value of the pulse interval register 25-3 is reset with the current set value.

The pulse interval register 25-3 is a register that receives the current set value from the adder 25-2, sets the count number in the pulse interval counter 15-2, and holds the count number.
The pulse interval counter 15-2 is a timer counter that subtracts the number of set clocks (pulse interval) set by the pulse interval register 25-3 every time the system clock period elapses. Also, the interval of ON or OFF change in the pulse train is monitored based on the set clock number (count value). When the count value becomes 0, the trigger signal 15c is turned ON / OFF with the interval data read unit 25-1. It is also a part sent out to the control unit 15-3.
The other components are the same as those in the first embodiment or the second embodiment, and thus the description thereof is omitted. The same components as those in the first embodiment or the second embodiment are denoted by the same reference numerals.

<Operation of Example 3>
FIG. 6 is an operation explanatory diagram of the third embodiment.
(A) is a figure which shows the air volume change of a thermal radiation fan, the vertical axis | shaft represents the air volume of a thermal radiation fan, and the horizontal axis represents time. The curve shown in this figure represents the air volume of the radiating fan based on the 1 / f fluctuation cycle component used in this embodiment. When the air volume of the heat dissipating fan is controlled as shown in this figure, the wind noise generated from the heat dissipating fan is similarly changed. Therefore, even if this wind noise is heard, no discomfort is felt.
(B) is the elements on larger scale of (a), (c) is a figure showing the control sequence of the pulse train (voltage application command signal 25d (FIG. 5)) for performing the air volume control shown in (b). is there.

The operation of the third embodiment will be described with reference to (c).
When the count value of the pulse interval counter 15-2 (FIG. 5) becomes 0 at time t1, the trigger signal 25c (FIG. 5) is turned on by the ON / OFF control unit 15-3 (FIG. 5) and the interval data read unit 25-1 (FIG. 5). 5).
When receiving the trigger signal 25c, the ON / OFF control unit 15-3 (FIG. 5) turns on the pulse in synchronization with the trigger signal 25c and turns on the voltage application command signal 25d (FIG. 5) from OFF (FIG. 5). “Change N”). When the fan driving unit 7 (FIG. 5) receives “change N”, the fan driving unit 7 (FIG. 5) sends a fan driving signal 7a (FIG. 3) to start driving the heat radiating fan 8 (FIG. 5).

  Upon receipt of the trigger signal 25c (FIG. 5), the interval data read unit 25-1 (FIG. 5) stores “change N + 1” data toward the 1 / f fluctuation characteristic ROM 23 (FIG. 5). The address 25a (FIG. 5) is transmitted, the interval data 25b (difference value of “change N + 1”) stored in the storage address 25a (FIG. 5) is read from the 1 / f fluctuation characteristic ROM 23 (FIG. 5), and the adder Send to 25-2. The adder 25-2 reads the previous count value (count value of “change N”) from the pulse interval register 25-3 (FIG. 5), and adds the interval data 25b (difference value of “change N + 1”). The current count value (the count value of “change N + 1”) is obtained, and the value of the pulse interval register 25-3 is reset. The pulse interval register 25-3 (FIG. 5) sets the current count value (the count value of “change N + 1”) in the pulse interval counter 15-2 (FIG. 5).

When the count value of the pulse interval counter 15-2 (FIG. 5) becomes 0 at time t2, the trigger signal 25c (FIG. 5) is turned on by the ON / OFF control unit 15-3 (FIG. 5) and the interval data read unit 25-1 (FIG. 5). 5).
When receiving the trigger signal 25c (FIG. 5), the ON / OFF control unit 15-3 (FIG. 5) turns off the pulse in synchronization with the trigger signal 25c (FIG. 5), and the voltage application command signal 25d (FIG. 5). 5) is turned off from on ("change N + 1"). When the fan driving unit 7 (FIG. 5) receives “change N + 1”, the fan driving unit 7 (FIG. 5) sends a fan driving signal 7a (FIG. 5) to stop the driving of the heat radiating fan 8 (FIG. 5).

  Upon receipt of the trigger signal 25c (FIG. 5), the interval data read unit 25-1 (FIG. 5) stores “change N + 2” data toward the 1 / f fluctuation characteristic ROM 23 (FIG. 5). The address 25a (FIG. 5) is transmitted, the interval data 25b (difference value of “change N + 2”) stored in the storage address 25a (FIG. 5) is read from the 1 / f fluctuation characteristic ROM 23 (FIG. 5), and the adder Send to 25-2. The adder 25-2 reads the previous count value (count value of “change N + 1”) from the pulse interval register 25-3 (FIG. 5), and adds the interval data 25b (difference value of “change N + 2”). The current count value (the count value of “change N + 2”) is obtained, and the value of the pulse interval register 25-3 (FIG. 5) is reset. The pulse interval register 25-3 (FIG. 5) sets the current count value (the count value of “change N + 2”) in the pulse interval counter 15-2 (FIG. 5).

When the count value of the pulse interval counter 15-2 (FIG. 5) becomes 0 at time t3, the trigger signal 25c (FIG. 5) is turned on by the ON / OFF control unit 15-3 (FIG. 5) and the interval data read unit 25-1 (FIG. 5). 5).
When the ON / OFF control unit 15-3 (FIG. 5) receives the trigger signal 25c (FIG. 5), it turns on the pulse in synchronization with the trigger signal 25c (FIG. 5), and the “change N + 2” voltage application command The signal 25d (FIG. 5) is turned on ("change N + 2"). When the fan driving unit 7 (FIG. 5) receives “change N + 2”, the fan driving unit 7 (FIG. 5) sends a fan driving signal 7a (FIG. 5) to start driving the heat radiating fan 8 (FIG. 5).

Upon receipt of the trigger signal 25c (FIG. 5), the interval data read unit 25-1 (FIG. 5) stores “change N + 3” data toward the 1 / f fluctuation characteristic ROM 23 (FIG. 5). The address 25a (FIG. 5) is transmitted, the interval data 25b (difference value of “change N + 3”) stored in the storage address 25a (FIG. 5) is read from the 1 / f fluctuation characteristic ROM 23 (FIG. 5), and the adder Send to 25-2 (FIG. 5). The adder 25-2 reads the previous count value (count value of “change N + 2”) from the pulse interval register 25-3 (FIG. 5), and adds the interval data 25b (difference value of “change N + 3”). The current count value (the count value of “change N + 2”) is obtained, and the value of the pulse interval register 25-3 (FIG. 5) is reset. The pulse interval register 25-3 (FIG. 5) sets the current count value (the count value of “change N + 3”) in the pulse interval counter 15-2.
Thereafter, the same operation is repeated.

The following points should be noted regarding the operation described above.
The fan drive unit 7 (FIG. 6) starts or stops driving the radiating fan 8 (FIG. 6) each time the pulse (voltage application command signal 15d (FIG. 6)) in (c) is received. That is, in (c), when the ratio of the pulse-on time to the pulse-off time is large within a predetermined time, the airflow of the heat dissipating fan is large. Conversely, when the ratio is small, the airflow of the heat dissipating fan is Get smaller. That is, the periodic component of 1 / f fluctuation can be approximated by pulse trains having different pulse widths and intervals.

<Effect of Example 3>
As described above, in the 1 / f fluctuation characteristic ROM 23, the difference between the current set value (count value of “change N + 1”) and the previous set value (count value of “change N”) is used as the interval data 25b. By storing the data, the data capacity of the 1 / f fluctuation characteristic ROM 23 can be further reduced as compared with the second embodiment.

<Configuration of Example 4>
FIG. 7 is a block diagram of the fan control device according to the fourth embodiment.
As shown in the figure, the fan control device according to the fourth embodiment includes a main control unit 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 3, a RAM 4, a fan drive pulse generation unit 35, and an in-device temperature detection unit 36. The common bus 6 and the fan drive unit 7 are provided.

  The fan drive pulse generation unit 35 is connected to the common bus 6 and reads the generation data of the pulse train stored in the 1 / f fluctuation characteristic ROM 3, and further generates a pulse train with a value obtained by correcting the generation data with the temperature in the apparatus. This is a part that is generated and sent to the fan drive unit 7 as the voltage application command signal 35d. It includes an interval data read unit 5-1, a pulse interval counter 5-2, a constant width pulse generation unit 5-3, a correction value calculation unit 35-1, and an adder 35-2.

  The correction value calculation unit 35-1 is a part that calculates a correction value for correcting the generation data of the pulse train read from the 1 / f fluctuation characteristic ROM 3 based on the internal temperature detected by the internal temperature detection unit 36. This correction value is represented by the number of system clocks.

The adder 35-2 adds the interval data 5b representing the interval of the pulses received from the interval data read unit 5-1, and the air volume correction value 35a based on the change in the apparatus temperature received from the correction value calculation unit 35-1. This is the part set in the pulse interval counter 5-2. A value obtained by adding the air volume correction value 35a and the interval data 5b is represented by the number of system clocks (an example).
The in-apparatus temperature detector 36 is a temperature sensor that detects the in-apparatus temperature.
Since other parts are the same as those in the first embodiment, description thereof is omitted.

<Operation of Example 4>
FIG. 8 is an operation explanatory diagram of the fourth embodiment.
(A) is the figure which expanded the figure which shows the air volume change of a thermal radiation fan, and is a figure applicable to FIG.2 (b) of Example 1. FIG. The vertical axis represents the air volume of the heat radiating fan, and the horizontal axis represents time. The curve shown in this figure represents the air volume of the radiating fan based on the 1 / f fluctuation cycle component used in this embodiment. When the air volume of the heat dissipating fan is controlled as shown in this figure, the wind noise generated from the heat dissipating fan is similarly changed. Therefore, even if this wind noise is heard, no discomfort is felt.
(B) is a figure showing the change of the apparatus internal temperature, (c) is a figure showing the air volume change of the heat radiating fan after temperature correction, and (d) is for performing the air volume control shown in (c). It is a figure showing the control sequence of the pulse train (voltage application command signal 35d (FIG. 7)).

The operation of the fourth embodiment will be described with reference to (c).
When the count value of the pulse interval counter 5-2 (FIG. 7) becomes 0 at time t1, the trigger signal 5c (FIG. 7) is changed to a constant width pulse generator 5-3 (FIG. 7) and an interval data read unit 5-1 (FIG. 7). 7).
When the constant width pulse generator 5-3 (FIG. 7) receives the trigger signal 5c (FIG. 7), it synchronizes with the trigger signal 5c (FIG. 7) and the Nth pulse (voltage application command signal having the same pulse width). 35d (FIG. 7)) is sent to the fan drive unit 7 (FIG. 7). When the fan drive unit 7 (FIG. 7) receives the Nth pulse, the fan drive unit 7 (FIG. 7) sends the fan drive signal 7a (FIG. 7) to drive the heat dissipation fan 8 (FIG. 7) for a predetermined time. .

  When receiving the trigger signal 5c (FIG. 7), the interval data read unit 5-1 (FIG. 7) stores the data of the (N + 1) th pulse toward the 1 / f fluctuation characteristic ROM 3 (FIG. 7). The address 5a (FIG. 7) is transmitted, and the interval between the pulses stored in the storage address 5a (FIG. 7) from the 1 / f fluctuation characteristic ROM 3 (FIG. 7) (the interval between the Nth pulse and the (N + 1) th pulse) Is read out and sent to the adder 35-2 (FIG. 7). At this time, the adder 35-2 (FIG. 7) adds the airflow correction value Nd + 1 based on the temperature in the apparatus at time t1 received from the correction value calculation unit 35-1 (FIG. 7), and adds the pulse interval counter 5- Set to 2.

When the count value of the pulse interval counter 5-2 (FIG. 7) becomes 0 at time t2, the trigger signal 5c (FIG. 7) is changed to a constant width pulse generator 5-3 (FIG. 7) and an interval data read unit 5-1 (FIG. 7). 7).
When the constant width pulse generator 5-3 (FIG. 7) receives the trigger signal 5c (FIG. 7), it synchronizes with the trigger signal 5c (FIG. 7), and the N + 1th pulse (voltage application command signal having the same pulse width). 35d (FIG. 7)) is sent to the fan drive unit 7 (FIG. 7). When the fan driving unit 7 (FIG. 7) receives the (N + 1) th pulse, the fan driving unit 7 (FIG. 7) sends the fan driving signal 7a (FIG. 7) to drive the heat radiating fan 8 (FIG. 7) for a predetermined time. .

  When the interval data read unit 5-1 (FIG. 7) receives the trigger signal 5c (FIG. 7), the N + 2th pulse data is stored in the 1 / f fluctuation characteristic ROM 3 (FIG. 7). The address 5a (FIG. 7) is transmitted, and the interval between the pulses stored in the storage address 5a (FIG. 7) from the 1 / f fluctuation characteristic ROM 3 (FIG. 7) (the interval between the (N + 1) th pulse and the (N + 2) th pulse) Is read out and sent to the adder 35-2 (FIG. 7). At this time, the adder 35-2 (FIG. 7) adds the airflow correction value Nd + 2 based on the temperature in the apparatus at time t2 received from the correction value calculation unit 35-1 (FIG. 7), and adds the pulse interval counter 5- 2 (FIG. 7).

When the count value of the pulse interval counter 5-2 (FIG. 7) becomes 0 at time t3, the trigger signal 5c (FIG. 7) is changed to a constant width pulse generator 5-3 (FIG. 7) and an interval data read unit 5-1 (FIG. 7). 7).
When the constant width pulse generator 5-3 (FIG. 7) receives the trigger signal 5c (FIG. 7), it synchronizes with the trigger signal 5c (FIG. 7), and the N + 2th pulse (voltage application command signal having the same pulse width). 35d (FIG. 7)) is sent to the fan drive unit 7 (FIG. 7). When the fan driving unit 7 (FIG. 7) accepts the (N + 2) th pulse, the fan driving unit 7 (FIG. 7) sends the fan driving signal 7a (FIG. 7) for a predetermined time to drive the heat radiating fan 8 (FIG. 7). .

When receiving the trigger signal 5c (FIG. 7), the interval data read unit 5-1 (FIG. 7) stores the data of the (N + 3) th pulse toward the 1 / f fluctuation characteristic ROM 3 (FIG. 7). The address 5a (FIG. 7) is transmitted, and the interval between the pulses stored in the storage address 5a (FIG. 7) from the 1 / f fluctuation characteristic ROM 3 (FIG. 7) (interval between the N + 2th pulse and the N + 3rd pulse) Is read out and sent to the adder 35-2 (FIG. 7). At this time, the adder 35-2 (FIG. 7) adds the airflow correction value Nd + 3 based on the temperature in the apparatus at time t3 received from the correction value calculation unit 35-1 (FIG. 7) to add the pulse interval counter 5- 2 (FIG. 7).
Thereafter, the same operation is repeated.

The following points should be noted regarding the operation described above.
The fan drive unit 7 (FIG. 1) drives the heat dissipation fan 8 (FIG. 1) for a predetermined time each time the pulse (voltage application command signal 5d (FIG. 1)) in (c) is received. That is, if the pulse interval of the pulse train in (c) is shortened, the airflow of the heat dissipating fan is increased, and conversely, if the interval of pulse trains (pulse interval) is increased, the airflow of the heat dissipating fan is decreased.

That is, it is possible to approximate the 1 / f fluctuation periodic component by changing the pulse interval of the pulse train. Further, although the pulse interval of the pulse train is changed by the air flow correction value 35a, the temperature in the apparatus does not change suddenly, so even if the pulse interval of the pulse train is changed by the air flow correction value 35a, the period of 1 / f fluctuations. It does not deviate significantly from the ingredients. Therefore, even if this wind noise is heard, there is no discomfort.
In the above description, when the airflow correction value 35a (FIG. 7) at a predetermined time is negative, the adder 35-2 (FIG. 7) determines the airflow correction value 35a from the interval data 5b (FIG. 7). Needless to say, the result is output after subtracting.

<Effect of Example 4>
As described above, in this embodiment, the fixing temperature can be properly maintained by adding the airflow correction value 35a (FIG. 7) for correcting the change in the apparatus temperature to the interval data 5b (FIG. 7). Therefore, in addition to the effect of the first embodiment, an effect that the image quality can be further improved is obtained.

<Configuration of Example 5>
FIG. 9 is a block diagram of the fan control device according to the fifth embodiment.
As shown in the figure, the fan control apparatus of the fifth embodiment includes a main control unit 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 3, a RAM 4, a fan drive pulse generation unit 5, a common bus 6, and a fan drive. Units 41-1 and 41-2, an operation input unit 42, and a selector 43.

  The fan drive units 41-1 and 41-2 send the fan drive signal 7a to the heat radiating fan 8 for a predetermined time based on the voltage application command signal 5d or the voltage application command signal 1a received from the selector 43, and the heat radiating fan. 8 is a part for driving. Although the number is limited to two here, it is not limited to this example, and three or more may be provided.

  The selector 43 receives a voltage application command signal 5d approximating the 1 / f fluctuation periodic component from the fan drive pulse generator 5 and a voltage application command signal having the same pulse width and pulse interval from the main controller 1 via the common bus 6. 1a is received, a voltage application command signal 5d is sent to at least one fan drive unit (for example, 41-1) selected based on the control of the operation input unit 42, and the remaining fan drive units (for example, 41-2) are sent. This is the part that sends out the voltage application command signal 1a.

The operation input unit 42 controls the selector 43 to select and send the voltage application command signal 5d or the voltage application command signal 1a to a plurality of fan drive units (in this case, 41-1 and 41-2). This is a control panel.
Other configurations are the same as those in the first embodiment, and thus the description thereof is omitted.

<Operation of Example 5>
The operator operates the operation input unit 42 to send the voltage application command signal 5d to the heat radiating fan selected from the plurality of heat radiating fans, and cause the remaining heat radiating fans to send the voltage application command signal 1a.
The heat radiating fan that has received the voltage application command signal 5d outputs an air volume approximated to the 1 / f fluctuation characteristic, and the heat radiating fan that has received the voltage application command signal 1a outputs a constant air volume that does not change with time. .

<Effect of Example 5>
As described above, in this embodiment, when a plurality of heat dissipation fans are individually controlled to approximate the 1 / f fluctuation characteristics, the plurality of voltage application command signals 5d are out of synchronization and output from the plurality of heat dissipation fans. The total air volume can be prevented from deviating from the 1 / f fluctuation characteristic, and the operator can select a fan that controls the 1 / f fluctuation characteristic, so by selecting the fan closest to the operator The effect that an unpleasant noise can be made hard to feel is obtained.

<Configuration of Example 6>
The fan control apparatus according to the sixth embodiment will be described below including the configuration and operation.
FIG. 10 is a block diagram of the fan control device according to the sixth embodiment.
As shown in the figure, the fan control device of Example 6 includes a main control unit 1, a control ROM 2, a 1 / f fluctuation characteristic ROM 3, a RAM 4, a fan drive pulse generation unit 5, a common bus 6, and a fan drive. Unit 7, heat dissipation fan power supply unit 51, operation input unit 52, and selector 53.

The radiating fan power supply unit 51 is a DC power supply that has a plurality of power supply voltages (V1, V2 as an example) having different voltage values, and applies a power supply voltage selected by the control of the selector 53 to the radiating fan 8. is there.
The operation input unit 52 is a control panel that allows the operator to select voltage values (V1, V2 as an example) to be applied to the heat dissipation fan 8.
The selector 53 is a selection circuit that applies a power supply voltage having a predetermined voltage value to the heat radiating fan 8 based on the selection of the operation input unit 52.
Since other components are the same as those of the first embodiment, description thereof is omitted.

  When an operator is aware of a temperature change inside the apparatus based on a slow factor of time change such as a room temperature change, the operator operates the operation input unit 52 to change the DC voltage V1 or V2 applied to the heat dissipation fan 8 as appropriate. .

<Effect of Example 6>
As described above, in the control circuit of the present embodiment, the DC voltage applied to the heat radiating fan 8 can be changed, so that the temperature change inside the apparatus based on a slow factor of time change such as room temperature change can be simplified. The effect that it can correct | amend easily with a structure is acquired.

1 is a block diagram of a fan control device according to Embodiment 1. FIG. FIG. 6 is an operation explanatory diagram of the first embodiment. It is a block diagram of the fan control apparatus of Example 2. FIG. 6 is an operation explanatory diagram of Embodiment 2. It is a block diagram of the fan control apparatus of Example 3. FIG. 9 is an operation explanatory diagram of Embodiment 3. It is a block diagram of the fan control apparatus of Example 4. FIG. 10 is an operation explanatory diagram of the fourth embodiment. FIG. 10 is a block diagram of a fan control device according to a fifth embodiment. FIG. 10 is a block diagram of a fan control device according to a sixth embodiment.

Explanation of symbols

1 Main control unit 2 Control ROM
3 1 / f fluctuation characteristic ROM
4 RAM
5 Fan Drive Pulse Generation Unit 5-1 Interval Data Read Unit 5-2 Pulse Interval Counter 5-3 Constant-Width Pulse Generation Unit 5a Storage Address 5b Interval Data 5c Trigger Signal 5d Voltage Application Command Signal 6 Common Bus 7 Fan Drive Unit (Pulse Signal output part)
7a Fan drive signal 8 Heat dissipation fan

Claims (7)

A fan control device that changes the air volume with time according to predetermined control characteristics,
A pulse signal instruction unit for instructing generation of a pulse train that approximates the control characteristics;
And a pulse signal output unit that outputs the pulse train based on an instruction from the pulse signal instruction unit. In the fan control device according to claim 1,
The pulse signal instruction unit
A storage unit for storing individual pulse intervals in the pulse train in order to approximate the control characteristic by a change in pulse interval of a pulse train having the same pulse width;
The pulse signal output unit is
Data reading means for reading the pulse interval from the storage unit;
A fan control device comprising pulse generation means for generating the pulse train based on the pulse interval read by the data reading means. In the fan control device according to claim 1,
The pulse signal instruction unit
A storage unit for storing individual pulse widths and individual pulse intervals in the pulse train in order to approximate the control characteristics by changes in pulse intervals of pulse trains having different pulse widths;
The pulse signal output unit is
Data reading means for reading out the pulse width and the pulse interval from the storage unit; and on / off control means for generating the pulse train based on the pulse width and the pulse interval read by the data reading means. Features a fan control device. In the fan control device according to claim 2,
In-apparatus temperature detection means for detecting the in-apparatus temperature;
Correction value calculating means for calculating an air flow correction value based on a change in the apparatus temperature;
A fan control device further comprising correction value adding means for outputting a pulse interval obtained by adding the airflow correction value to the pulse interval read by the data reading means to the pulse width generating means. In the fan control device according to claim 2,
Accepting a pulse train having the same pulse width and pulse interval as the pulse train output from the pulse signal output unit, and outputting the pulse train output from the pulse signal output unit from at least one output end of the plurality of output ends, Further comprising output selection means for outputting a pulse train having the same pulse width and pulse interval from the output end,
A fan control device characterized in that the output of the output selection means is supplied to a plurality of heat dissipating fans. In the fan control device according to any one of claims 1 to 3,
A fan control device further comprising power supply voltage selection means for receiving a plurality of power supply voltages having different voltage values supplied to the heat radiating fan, selecting a predetermined voltage value and supplying the selected voltage value to the heat radiating fan. In the fan control device according to any one of claims 1 to 6,
The control characteristic is
A fan control device characterized by air flow control based on a 1 / f fluctuation cycle component.

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