JP4321091B2 - Image forming apparatus and fan control method for image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a printer, a copying machine, and a facsimile machine, and more particularly to a technique for controlling driving of a fan provided in the apparatus.
[0002]
[Prior art]
In general, an electrophotographic image forming apparatus such as a printer, a copying machine, and a facsimile apparatus is provided with a cooling fan for cooling the inside of the apparatus. The cooling fan can be switched to high speed driving or low speed driving if it can be driven on / off or the driving speed can be switched. When the cooling fan is driven, there is a problem that noise is generated by wind noise and vibration, and power consumption is increased. In particular, when the cooling fan is driven at a high speed, although the cooling capacity is improved, the above-described problems are increased. Therefore, conventionally, driving of the cooling fan (or high speed driving) is performed only when necessary (see, for example, Patent Documents 1 and 2). The apparatus described in Patent Document 1 is configured to start driving the cooling fan when the number of formed images or the image forming time exceeds a predetermined value. In the apparatus described in Patent Document 2, the cooling fan that is being driven at a high speed is switched to a low speed drive after a lapse of time corresponding to the number of continuous prints. That is, as the number of continuous prints increases, the high-speed drive time after the end of printing is lengthened.
[0003]
[Patent Document 1]
JP-A-9-26745 (paragraph [0005])
[Patent Document 2]
JP-A-9-311613 (paragraph [0068])
[0004]
[Problems to be solved by the invention]
However, depending on the configuration of the image forming apparatus and the cooling target of the cooling fan, the cooling fan does not operate until the number of images to be formed and the image forming time reach a predetermined value, or the cooling fan is simply driven at high speed when printing is started. Therefore, there is a possibility that the temperature rise cannot be sufficiently suppressed. Therefore, it is desired to suitably control the driving of the cooling fan in accordance with the operation status of the apparatus.
[0005]
The present invention has been made in view of the above problems, and provides an image forming apparatus and a fan control method for an image forming apparatus that can suitably control the driving of a cooling fan in accordance with the operation status of the apparatus. Objective.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to the present invention forms an electrostatic latent image on a rotating photoconductor, visualizes the electrostatic latent image, and forms a toner image. A plurality of motors for driving each part of the apparatus, a power supply circuit for supplying power to the plurality of motors, a power cooling fan that can be switched to at least two stages of high-speed driving and low-speed driving, and cools the power supply circuit; And a fan control means for switching the driving speed of the power cooling fan from the low speed driving to the high speed driving in accordance with an increase in the number of motors in the operating state.
[0007]
In order to achieve the above object, the fan control method of the image forming apparatus according to the present invention forms an electrostatic latent image on a rotating photosensitive member, and visualizes the electrostatic latent image to form a toner image. In the image forming apparatus, the power supply circuit that supplies power to a plurality of motors that drive each part of the apparatus is cooled, and the power cooling fan that can switch the driving speed in at least two stages of high speed driving and low speed driving The speed is switched from low speed driving to high speed driving in accordance with an increase in the number of motors in an operating state.
[0008]
According to these configurations, the driving speed of the cooling fan that can be switched to at least two stages of high-speed driving and low-speed driving is switched according to the operation status of the plurality of motors, for example, depending on the operation status of the plurality of motors. When the temperature rises greatly, switching to high speed driving can suppress the temperature rise. For example, when the temperature does not increase so much due to the operating conditions of multiple motors, switching to low speed driving can suppress noise and reduce power consumption. Reduction can be achieved. Thereby, the cooling fan can be driven efficiently. A plurality of motors for driving each part of the apparatus include a motor for rotating the photosensitive member, a motor for forming an electrostatic latent image, for example, a motor for driving an exposure unit, and developing the electrostatic latent image to form a toner image. For example, a motor for driving the developing unit can be used. Further, in the case where the toner image is transferred onto the transfer paper and provided with a transport means for transporting the transfer paper, a motor for driving the transport means may be used.
[0009]
In addition, since the degree of increase in the temperature of the power supply circuit changes according to the operation status of the plurality of motors, by switching the driving speed of the power cooling fan according to the operation status of the plurality of motors, The temperature rise can be suppressed efficiently.
[0010]
In addition, it further comprises a high speed condition determination means for determining whether or not a predetermined high speed switching condition is satisfied, and the high speed condition determination means satisfies a motor condition in which at least one of the plurality of motors is in an operating state, The fan control means determines that the high-speed switching condition is satisfied, and the fan control means switches the power supply cooling fan to high-speed driving when the high-speed condition determination means determines that the high-speed switching condition is satisfied. Good.
[0011]
If at least one of the plurality of motors is in the operating state, the temperature of the power supply circuit will increase greatly. According to this configuration, if at least one of the plurality of motors satisfies the motor condition in the operating state, Since it is determined that the high-speed switching condition is satisfied, and it is determined that the high-speed switching condition is satisfied, the power supply cooling fan is switched to high-speed driving, so that the temperature increase of the power supply circuit can be suitably suppressed.
[0012]
The apparatus further comprises temperature detecting means for detecting an atmospheric temperature in the apparatus, and the high speed condition determining means satisfies the motor condition and satisfies a temperature condition in which a temperature detected by the temperature detecting means is equal to or higher than a predetermined value. It may be determined that the high-speed switching condition is satisfied.
[0013]
When the detected temperature of the temperature detecting means is less than the predetermined value, it is considered that there is little need to drive the power supply cooling fan at high speed. According to this configuration, at least one of the plurality of motors is in an operating state. If the temperature condition that satisfies the conditions and the temperature detected by the temperature detection means is equal to or higher than the specified value, it is determined that the high-speed switching condition is satisfied. It is possible to switch to driving, thereby suppressing an increase in power consumption.
[0014]
Further, it further comprises a low speed condition determining means for determining whether or not a predetermined low speed switching condition is satisfied, and the low speed condition determining means determines that the low speed switching condition is satisfied when all of the plurality of motors stop operating. The fan control means switches the power cooling fan to low speed driving when the low speed condition determining means determines that the low speed switching condition is satisfied during high speed driving of the power cooling fan. It is good.
[0015]
If all of the plurality of motors stop operating, the temperature increase degree of the power supply circuit is considered to decrease, but according to this configuration, when all of the plurality of motors stop operating during the high-speed driving of the power cooling fan. Since it is determined that the low-speed switching condition is satisfied and the power-supply cooling fan is switched to low-speed driving, noise suppression and power consumption reduction can be achieved. Can continue.
[0016]
And a fixing cooling fan that cools a fixing unit that fixes the toner image transferred onto the transfer paper to the transfer paper and that can be switched to at least two stages of high speed driving and low speed driving. Switching control of the driving speed of the fixing cooling fan may be performed according to the operation status of the fixing unit.
[0017]
If the temperature rise is left unattended, it will cause a failure of the apparatus. According to this configuration, the power supply cooling fan and the fixing cooling fan for suppressing the temperature rise are at least operated at high speed and low speed. It is possible to switch between two stages, control the switching of the driving speed of the power cooling fan according to the operating status of the plurality of motors, and control the switching of the driving speed of the fixing cooling fan according to the operating status of the fixing means. Thus, the power supply cooling fan and the fixing cooling fan can be driven as necessary, and the control efficiency and power efficiency can be improved.
[0018]
In addition, a non-cooling fan that operates at a constant driving speed may be further provided, and the fan control unit may drive the non-cooling fan during a specific operation in an image forming operation. According to this configuration, the non-cooling fan that is not for suppressing the temperature rise that causes the failure of the apparatus is driven at a specific operation in the image forming operation as operating at a constant driving speed. The control configuration of the non-cooling fan can be simplified. The specific operation means an operation that requires driving of the non-cooling fan. For example, when the non-cooling fan is a fan for sucking ozone generated in the vicinity of the photoconductor, When the operation of generating ozone near the body is a specific operation, for example, when the non-cooling fan forms a toner image, for example, a fan for sucking the toner scattered from the developing unit, the toner is discharged from the developing unit. The scattered operation is a specific operation.
[0019]
In addition, according to this configuration, a cooling fan for suppressing a temperature rise that causes a failure of the apparatus, and a plurality of fans of a non-cooling fan that is not for suppressing the temperature rise, The cooling fan can be switched to at least two stages of high-speed driving and low-speed driving, and the non-cooling fan is operated at a constant driving speed. The control efficiency and power efficiency of the entire apparatus can be improved.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing an embodiment of an image forming apparatus according to the present invention. This apparatus forms a full color image by superposing four color toners of yellow (Y), cyan (C), magenta (M), and black (K), or monochrome using only black (K) toner. An image forming apparatus for forming an image. In this image forming apparatus, when a print command signal including an image signal is supplied from an external device such as a host computer to a controller (CPU) 160 (see FIG. 2), the image forming apparatus is provided in the apparatus main body 1 in accordance with the command from the CPU 160. The engine unit EG executes a predetermined image forming operation to form an image corresponding to the image signal on the sheet S.
[0021]
In the engine unit EG, the photosensitive member 22 is provided so as to be rotatable in an arrow direction D1 in FIG. Further, a charging unit 23, a rotary developing unit 4 and a cleaning unit 25 are arranged around the photosensitive member 22 along the rotation direction D1. The charging unit 23 is applied with a predetermined charging bias, and uniformly charges the outer peripheral surface of the photoconductor 22 to a predetermined surface potential. Further, the photosensitive member 22, the charging unit 23, and the cleaning unit 25 integrally constitute the photosensitive member cartridge 2, and the photosensitive member cartridge 2 is integrally detachable from the apparatus main body 1.
[0022]
Then, the light beam L is irradiated from the exposure unit 6 toward the outer peripheral surface of the photosensitive member 22 charged by the charging unit 23. The exposure unit 6 exposes the surface of the photoconductor 22 with a light beam L corresponding to an image signal given from an external device, and forms an electrostatic latent image corresponding to the image signal.
[0023]
The electrostatic latent image thus formed is developed with toner by the developing unit 4. That is, the developing unit 4 is configured as a support frame 40 that is rotatably provided around a rotation shaft 4a, and a cartridge that can be attached to and detached from the support frame 40, and that is, a yellow developer that contains toner of each color. 4Y, a developing unit 4C for cyan, a developing unit 4M for magenta, and a developing unit 4K for black. The developing unit 4 is controlled by the CPU 160. Based on the control command from the CPU 160, the developing unit 4 is driven to rotate, and the developing units 4Y, 4C, 4M, and 4K are selectively brought into contact with the photosensitive member 22 or separated by a predetermined gap. When the developing unit 4 is positioned at a predetermined developing position facing each other, a developing roller (developing roller 41Y in FIG. 1) is provided in the developing unit (developing unit 4Y in FIG. 1) and carries toner of a selected color. ) To apply toner to the surface of the photosensitive member 22. As a result, the electrostatic latent image on the photosensitive member 22 is visualized with the selected toner color.
[0024]
The toner image developed by the developing unit 4 as described above is primarily transferred onto the intermediate transfer belt 71 of the transfer unit 7 in the primary transfer region TR1. The intermediate transfer belt 71 is stretched around a plurality of rollers 72 to 75, and the roller 73 is driven to rotate by a photosensitive member driving motor 92 (see FIG. 2) so as to rotate in a predetermined rotation direction D2. It is configured. When a color image is transferred to the sheet S, each color toner image formed on the photosensitive member 22 is superimposed on the intermediate transfer belt 71 to form a color image and taken out from the cassette 8 one by one. Then, the color image is secondarily transferred onto the sheet S conveyed along the conveyance path F to the secondary transfer region TR2.
[0025]
At this time, in order to correctly transfer the image on the intermediate transfer belt 71 to a predetermined position on the sheet S, the timing of feeding the sheet S to the secondary transfer region TR2 is managed. Specifically, a gate roller 81 is provided on the transport path F on the front side of the secondary transfer region TR2, and the gate roller 81 rotates in accordance with the timing of the circumferential movement of the intermediate transfer belt 71. S is sent to the secondary transfer region TR2 at a predetermined timing.
[0026]
Further, the sheet S on which the color image is transferred in this way is fixed by the color image on the sheet S while being conveyed by the fixing unit 9, and further on the upper surface portion of the apparatus main body 1 via the pre-discharge roller 82 and the discharge roller 83. It is conveyed to the provided discharge tray unit 89. Further, when images are formed on both sides of the sheet S, when the rear end portion of the sheet S on which the image is formed on one side as described above is conveyed to the reversal position PR behind the pre-discharge roller 82. The rotation direction of the discharge roller 83 is reversed, whereby the sheet S is conveyed in the direction of the arrow D3 along the reverse conveyance path FR. Then, the sheet is again placed on the transport path F before the gate roller 81. At this time, the image is transferred first on the surface of the sheet S on which the image is transferred by contacting the intermediate transfer belt 71 in the secondary transfer region TR2. It is the opposite surface. In this way, images can be formed on both sides of the sheet S. Thus, in this embodiment, the sheet S corresponds to “transfer paper” of the present invention, and the fixing unit 9 corresponds to “fixing means” of the present invention.
[0027]
Further, as shown in FIG. 1, in the vicinity of the exposure unit 6, a power supply board 62 on which a power supply circuit 61 (see FIG. 2) and a motor drive circuit 95 (see FIG. 2) described later are mounted, and this power supply board. The above-mentioned circuits 61 and 95 on 62 and a cooling fan 101 for cooling the scanner motor 91 (see FIG. 2) of the exposure unit 6 are arranged. Further, a cooling fan 102 for cooling the fixing unit 9 is disposed in the vicinity of the fixing unit 9. Further, an ozone suction fan 103 that sucks ozone generated by the high-voltage charging unit 23 toward an ozone filter (not shown) is disposed in the vicinity of the primary transfer region TR1. Further, on the left side of the developing unit 4, an ozone suction fan 104 that sucks ozone toward an ozone filter (not shown) and a toner suction that sucks toner scattered from the developing unit 4 toward a toner filter (not shown). A fan 105 is provided. Further, a temperature sensor 63 is disposed in the vicinity of the gate roller 81 and at a position facing the conveyance path F of the sheet S. The temperature sensor 63 detects the ambient temperature, and the detected temperature is used to determine the transfer bias of the transfer unit 7 and is used to control the cooling fan 101 as will be described later. Thus, in this embodiment, the cooling fan 101 corresponds to the “power supply cooling fan” of the present invention, the cooling fan 102 corresponds to the “fixing cooling fan” of the present invention, and the ozone suction fan 103, 104 and the toner suction fan 105 correspond to the “non-cooling fan” of the present invention, and the temperature sensor 63 corresponds to the “temperature detecting means” of the present invention.
[0028]
FIG. 2 is a diagram showing an electrical configuration of the image forming apparatus. As shown in FIG. 2, the image forming apparatus is provided with a controller (CPU) 160 that controls the operation of each unit, and is connected to a main body memory 161 and the like. The main body memory 161 includes a ROM section that stores a control program for the CPU 160 and a RAM section that temporarily stores image signals and other data sent from an external device, and preferably a nonvolatile memory is used. As such a nonvolatile memory, for example, an EEPROM such as a flash memory, a ferroelectric memory (Ferroelectric RAM), or the like can be employed.
[0029]
The scanner motor 91 rotates the polygon mirror of the exposure unit 6 at a high speed at a preset rotation speed, for example, 30,000 rpm (rotation / minute). For example, a DC servo motor is used. The photoconductor drive motor 92 rotates the photoconductor 22 and the intermediate transfer belt 71 at substantially the same peripheral speed. For example, a stepping motor is used. The conveyance system drive motor 93 is configured to rotate the gate roller 81, the pre-discharge roller 82, the discharge roller 83, the heating roller of the fixing unit 9 and the like to convey the sheet S at a predetermined speed. For example, a DC servo motor is used. . The development system drive motor 94 rotationally drives the development unit 4 and also rotationally drives a development roller (for example, the development roller 41Y in FIG. 1) positioned at the development position. For example, a stepping motor is used.
[0030]
The power supply circuit 61 generates a power supply for supplying power to the motors 91 to 94, and generates a predetermined DC voltage (for example, DC 24V) from a commercial power supply of AC 100V, for example. Then, the CPU 160 outputs a control command to the motor drive circuit 95, and the motor drive circuit 95 outputs the voltage generated by the power supply circuit 61 to each of the motors 91 to 94 in accordance with this control command. A drive signal corresponding to the motors 91 to 94 (for example, a drive pulse signal having a predetermined number of pulses) is output.
[0031]
The fan motors 111 to 115 rotate the fans 101 to 105, respectively. For example, a DC motor is used. Among them, the fan motors 111 and 112 that drive the cooling fans 101 and 102 are configured so that the driving speed can be switched between two stages of high speed driving and low speed driving, and the fan motor 113 that drives the suction fans 103 to 105. ˜115 can be driven only at a constant driving speed.
[0032]
The CPU 160 controls on / off of driving of the fan motors 111 and 112 and performs switching control between high speed driving and low speed driving by switching the voltage level output from the motor driving circuit 116 to the fan motors 111 and 112. As a result, the driving of the cooling fans 101 and 102 is controlled. Further, the CPU 160 controls on / off of driving of the fan motors 113 to 115 via the motor driving circuit 117. As a result, the driving of the suction fans 103 to 105 is controlled.
[0033]
Further, the developing device operation unit 150 is provided so as to be exposed when, for example, an external cover (not shown) of the apparatus main body 1 is opened. In this image forming apparatus, when the user operates the developing device operation unit 150, the rotary developing unit 4 is moved to the attaching / detaching position, so that the developing device can be attached / detached for the first time. Specifically, when the user presses the button corresponding to the toner color desired to be replaced among the developer operation buttons 151Y, 151C, 151M, 151K provided in the developer operation unit 150, the development unit 4 rotates by a predetermined amount. The developer is driven and positioned at the attachment / detachment position, and the developer corresponding to the selected toner color appears in a developer opening (not shown) exposed when the external cover is opened, for example.
[0034]
The CPU 160 has a function as a mode control unit that controls the operation mode of the image forming apparatus. For example, a predetermined initial process is executed when the power is turned on. After the initial process is executed, if the print command signal is not input from the external device, the process shifts to the standby mode. When a print command signal is input from an external device, the image forming mode is entered. Further, when the external cover is opened, the operation mode shifts to the standby mode. When any of the developing device operation buttons 151Y, 151C, 151M, 151K is pressed in this standby mode, the operation mode shifts to the cartridge replacement mode.
[0035]
Then, the CPU 160 controls the operation of each unit according to the operation mode. For example, the developing unit 4 is positioned at a predetermined home position in the standby mode, positioned at the developing position in the image forming mode, and positioned at the attachment / detachment position in the cartridge replacement mode. For example, the fixing unit 9 is maintained at a predetermined fixing temperature (for example, 180 ° C.) in the image forming mode, and is maintained at a standby temperature (for example, 160 ° C.) lower than the fixing temperature in the standby mode and the cartridge replacement mode. Further, for example, the driving speed of the cooling fan 102 (fan motor 112) is switched according to the operation status of the fixing unit 9. That is, for example, when the fixing unit 9 exceeds the fixing temperature, it is driven at a high speed, and when it is lower than the standby temperature, it is driven at a low speed.
[0036]
Further, the CPU 160 drives, for example, the ozone suction fans 103 and 104 (fan motors 113 and 114) in the image forming mode in which the charging unit 23 operates, and stops in the standby mode and the cartridge replacement mode. Further, for example, the toner suction fan 105 (fan motor 115) is driven in the image forming mode and the cartridge replacement mode in which the developing unit 4 is driven to rotate, and is stopped in the standby mode. Thus, in this embodiment, in the case of the ozone suction fans 103 and 104, the image forming mode corresponds to the “specific operation” of the present invention, and in the case of the toner suction fan 105, the image forming mode and the cartridge replacement mode are set. This corresponds to the “specific operation” of the present invention.
[0037]
Here, drive control of the cooling fan 101 (fan motor 111) by the CPU 160 will be described. As described above, the cooling fan 101 cools the power supply circuit 61 and the motor drive circuit 95 mounted on the power supply board 62. For this reason, it is desirable that the cooling fan 101 is driven according to the operation status of the motors 91 to 94, not whether or not the operation mode is the image forming mode.
[0038]
Therefore, the CPU 160 determines whether or not a predetermined high-speed switching condition is satisfied. If the CPU 160 determines that the high-speed switching condition is satisfied, the CPU 160 switches the fan motor 111 to high-speed driving. In this embodiment, the CPU 160 determines whether or not a motor condition in which at least one of the motors 91 to 94 is in an operating state is satisfied, and the temperature detected by the temperature sensor 63 is equal to or higher than a predetermined value (for example, 45 ° C.). It is determined whether or not the temperature condition is satisfied. CPU 160 determines that the high-speed switching condition is satisfied when the motor condition is satisfied and the temperature condition is satisfied.
[0039]
Further, the CPU 160 determines whether or not a predetermined low speed switching condition is satisfied, and when it is determined that the low speed switching condition is satisfied during the high speed driving of the fan motor 111, the fan motor 111 is switched to the low speed driving. In this embodiment, the CPU 160 determines that the low speed switching condition is satisfied when all of the motors 91 to 94 stop operating. Furthermore, when all the motors 91 to 94 are stopped for a predetermined time, the CPU 160 outputs a pause instruction signal and stops driving the fan motor 111.
[0040]
Here, “the motor is in an operating state” includes a hold state in which the motor is not rotationally driven. That is, the operation state of the motors 91 to 94 means a state in which power is supplied from the power supply circuit 61 to the motors 91 to 94 via the motor drive circuit 95. Thus, in this embodiment, the power supply circuit 61 and the motor drive circuit 95 correspond to the “power supply circuit” of the present invention, and the CPU 160 performs the “fan control means”, “high speed condition determination means” and “low speed” of the present invention. It corresponds to “condition determination means”. Hereinafter, an example of the control procedure of the fan motor 111 will be described.
[0041]
FIG. 3 is a flowchart showing an example of the control procedure of the fan motor 111. The CPU 160 executes the operation of FIG. 3 at a predetermined cycle (for example, 30 msec). In FIG. 3, it is first determined whether or not there is a pause instruction (# 10). If there is no pause instruction (NO in # 10), it is determined whether or not the fan motor 111 is stopped (# 12). If not stopped (NO in # 12), the process proceeds to the next step # 16. If stopped (YES in # 12), the fan motor 111 is driven at a low speed because there is no pause instruction (# 14). ), Go to next Step # 16.
[0042]
In step # 16, it is determined whether or not the fan motor 111 is currently driven at a low speed. If the fan motor 111 is currently driven at a low speed (YES in # 16), it is determined whether or not the high speed switching condition is satisfied ( # 18) If the high speed switching condition is satisfied (YES in # 18), the fan motor 111 is switched to high speed driving (# 20), and the process proceeds to the next step # 22. On the other hand, if NO at steps # 16 and # 18, the process proceeds to the next step # 22.
[0043]
In step # 22, it is determined whether or not the fan motor 111 is currently being driven at high speed. If it is being driven at high speed (YES in # 22), it is determined whether or not the low speed switching condition is satisfied ( # 24) If the low speed switching condition is satisfied (YES in # 24), the fan motor 111 is switched to low speed driving (# 26), and this routine is terminated. On the other hand, if NO at steps # 22 and # 24, this routine is ended as it is.
[0044]
If there is a pause instruction signal in the first step # 10 (YES in # 10), the driving of the fan motor 111 is stopped (# 28), and the process proceeds to step # 16. At this time, step # 16 is NO and step # 22 is NO, so this routine is terminated as it is.
[0045]
As described above, according to this embodiment, when the motor condition in which at least one of the motors 91 to 94 is in the operating state is satisfied and the temperature condition of the temperature sensor 63 is equal to or higher than the predetermined value is satisfied, the high-speed switching is performed. Since it is determined that the condition is satisfied and the fan motor 111 (that is, the cooling fan 101) is driven at high speed, overheating of the power supply circuit 61 and the motor drive circuit 95 can be prevented in advance. At this time, since the existing temperature sensor 63 that determines the transfer condition is used, it is not necessary to provide a separate temperature sensor for driving control of the cooling fan 101.
[0046]
Further, according to this embodiment, during the high speed driving of the fan motor 111, when all of the motors 91 to 94 are stopped, it is determined that the low speed switching condition is satisfied, and the high speed driving is switched to the low speed driving. It is possible to avoid driving the cooling fan 101 at a higher speed than necessary, thereby suppressing noise and reducing power consumption.
[0047]
Further, if the temperature rise is left unattended, it causes a failure of the apparatus. According to this embodiment, only the cooling fans 101 and 102 for suppressing such a temperature rise are driven at high speed and low speed. Therefore, the necessary cooling capacity can be obtained with certainty. Further, since the non-cooling suction fans 103 to 105 can be driven only at a constant driving speed, the control configuration can be simplified, and the control efficiency and the power efficiency can be improved.
[0048]
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the invention. For example, in the above embodiment, the temperature condition is added to the determination of the high-speed switching condition. That is, the CPU 160 determines that the high-speed switching condition is satisfied when the motor condition in which at least one of the motors 91 to 94 is in the operating state is satisfied and the temperature condition that the temperature sensor 63 detects is equal to or higher than the predetermined value. ing. However, the present invention is not limited to this. For example, the temperature condition may be removed, and the CPU 160 may determine that the high-speed switching condition is satisfied when the motor condition in which at least one of the motors 91 to 94 is in an operating state is satisfied, and drive the cooling fan 101 at a high speed. . Even in this case, the effect of driving the cooling fan 101 in accordance with the operation status of the motors 91 to 94 can be achieved. However, when the temperature detected by the temperature sensor 63 is lower than the predetermined value, it is considered that the necessity for driving the cooling fan 101 at a high speed is low, so the above embodiment is preferable from the viewpoint of noise and power consumption.
[0049]
In the above embodiment, the cooling fans 101 and 102 (fan motors 111 and 112) can be switched between two stages of high speed driving and low speed driving. However, the present invention is not limited to this. In short, it is sufficient if the drive speed can be switched.
[0050]
Further, the above embodiment includes a rotary developing unit that can be equipped with four developing devices corresponding to four colors of yellow, cyan, magenta, and black, and an image on both sides of the sheet S by including a reversal conveyance path FR. It is an apparatus that can form. The present invention is not limited to this. For example, the present invention can also be applied to an apparatus including a developing unit that can be equipped with a different number of developing devices, and an apparatus that forms an image only on one side of the sheet S. It is. In particular, the present invention is effective when applied to an image forming apparatus having various operation modes in which a motor is driven in addition to the image forming mode.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a diagram showing an electrical configuration of the image forming apparatus.
FIG. 3 is a flowchart of an operation example of a fan motor for power supply cooling.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 9 ... Fixing unit (fixing means), 22 ... Photoconductor, 61 ... Power supply circuit (power supply circuit), 63 ... Temperature sensor (temperature detection means), 91-94 ... Motor, 95 ... Motor drive circuit (power supply circuit) DESCRIPTION OF SYMBOLS 101 ... Cooling fan (power supply cooling fan) 102 ... Cooling fan (fixing cooling fan) 103-105 ... Suction fan (non-cooling fan), 160 ... CPU (fan control means, high speed condition determination means) , Low speed condition determining means), S ... sheet (transfer paper)

Claims (7)

In an image forming apparatus that forms an electrostatic latent image on a rotating photoreceptor and visualizes the electrostatic latent image to form a toner image.
A plurality of motors for driving each part of the device;
A power supply circuit for supplying power to the plurality of motors;
A power cooling fan that can be switched to at least two stages of high speed driving and low speed driving, and that cools the power supply circuit;
An image forming apparatus comprising: fan control means for switching the driving speed of the power cooling fan from the low speed driving to the high speed driving according to an increase in the number of the motors in an operating state. When at least one of the plurality of motors is in an operating state, it further comprises a high speed condition determining means that determines that a high speed switching condition is satisfied,
The image forming apparatus according to claim 1, wherein the fan control unit switches the power supply cooling fan to a high-speed drive when the high-speed condition determination unit determines that the high-speed switching condition is satisfied. Temperature detecting means for detecting the ambient temperature in the apparatus;
High-speed condition determination means for determining that a high-speed switching condition is satisfied when at least one of the plurality of motors is in an operating state and the temperature detected by the temperature detection means is equal to or higher than a predetermined value;
The image forming apparatus according to claim 1, wherein the fan control unit switches the power supply cooling fan to a high-speed drive when the high-speed condition determination unit determines that the high-speed switching condition is satisfied. When all of the plurality of motors stop operating, further comprising a low speed condition determining means for determining that the low speed switching condition is satisfied,
4. The fan control means switches the power cooling fan to low speed driving when the low speed condition determining means determines that the low speed switching condition is satisfied during high speed driving of the power cooling fan. The image forming apparatus described in 1. A fixing cooling fan that cools a fixing unit that fixes the toner image transferred onto the transfer paper to the transfer paper, and that can be switched between at least two stages of high speed driving and low speed driving;
The image forming apparatus according to claim 2, wherein the fan control unit performs switching control of a driving speed of the fixing cooling fan in accordance with an operation state of the fixing unit. It further includes a non-cooling fan that operates at a constant driving speed,
The image forming apparatus according to claim 1, wherein the fan control unit drives the non-cooling fan during a specific operation in an image forming operation. In an image forming apparatus that forms an electrostatic latent image on a rotating photoreceptor and visualizes the electrostatic latent image to form a toner image.
To cool the power supply circuit for supplying power to a plurality of motors for driving the respective units of the apparatus, the driving speed of the switchable power cooling fan drive speed at least two stages of high-speed driving and low speed driving, operation A fan control method for an image forming apparatus, wherein the low speed drive is switched to the high speed drive in accordance with an increase in the number of motors in a state.

Images