JPH04318567A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent temperature rise and the continuation of a high temperature from transiently occuring after disconnecting a main power source in an image forming device which is provided with an image forming means having a heat source which generates heat when the main power source is turned on inside and where an air blowing fan for cooling is operated at the same time. CONSTITUTION:A time constant circuit consisting of a resistance 2 and a capacitor 3 is provided, and when the main DC power source 10 is inputted, the capacitor 3 is charged and an FET switch 6 is connected, then a cold air fan 1 is rotated to cool the inside of the image forming device. When the main DC power source 10 is disconnected, the time constant circuit works and the FET switch 6 is connected for a fixed time, so that the fan 1 is rotated for the fixed time by a battery 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus that cools the apparatus by forcibly generating air flow.

0002

2. Description of the Related Art An image recording apparatus using a light beam 41 shown in FIG. After forming a latent image on the latent image 40, toner is supplied to the developing device 43 to form a visible image, and the visible image is transferred to the paper sheet S conveyed from the paper feed section 44 to the transfer charger 45. It is sent to the fuser 46 and heated by the fuser 46.
It is fixed by pressing it with a roller. Conventionally, in an image forming apparatus having such a configuration, the amount of heat generated by heating the fixing device 46 is large, and the primary charger 42 and the transfer charger 4
Since 5 often uses a corona discharger, a cooling fan 1 is installed to prevent the generated heat and ozone from accumulating inside the device, and when the device is in operation, the air inside is removed. or outside air into the inside of the device.

0003

However, in the conventional example described above, the cooling fan is rotated only when the image forming apparatus is in operation, that is, when the main switch of the apparatus is connected. If it occurs only when the device is operating, there is little problem, but if a member with a large heat capacity, such as a fuser, is heated, the high temperature state will persist for a while even after the device has finished operating. The heat generated during this time ends up being trapped inside the device, and the temperature of some of the other components of the device that are being cooled by the cooling fan increases transiently, or the high temperature persists and causes damage to that component. It will have a negative impact on. Furthermore, when performing maintenance on the device, there is a drawback that it takes a long time to wait until the internal temperature drops.

0004

[Means for Solving the Problems] According to the present invention, by rotating a cooling fan for a certain period of time after the main switch of an image forming apparatus is turned off, the apparatus can be cooled quickly, thereby improving maintenance and reliability of the apparatus. It is designed to improve the

The present invention has an image forming means inside which is equipped with a heat source that generates heat when the main power is turned on, and a cooling fan that is operated to cool the inside of the apparatus when the main power is turned on. The image forming apparatus is characterized in that the image forming apparatus includes a device that rotates the cooling fan for a certain period of time after the main power source is cut off.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is one of the embodiments that best represents the present invention. The blower fan 1 shown in FIG. 4 is a fan driven by a DC motor in this embodiment. The resistor 2 together with the capacitor 3 determines the rotation duration of the fan 1 after the main switch is disconnected. The diode 4 prevents the charge accumulated in the capacitor 3 from flowing to anything other than the resistor 2. Each current limiting resistor 5 prevents too much current from flowing from the power source. The FET switch 6 is a switch that controls ON/OFF of the blower fan 1. Regulator 7 is main DC power supply 10
Create the desired voltage from The storage battery 8 becomes a power source for the blower fan 1 after the main switch is turned off. The charger 9 is provided for charging the storage battery 8 while the main switch is connected. capacitor 1
1 is for noise removal. The backflow prevention diodes 12 and 14 are elements for preventing the output from the storage battery 8 from flowing toward the main power source after the main switch is disconnected. The backflow prevention diode 13 is connected to the main DC when the main switch is connected.
This is provided to prevent the output from the power source 10 from flowing into the storage battery 8.

Now assume a steady state in which the master switch is connected. At this time, one of the currents flowing from the main DC power supply 10 passes through the regulator 7 and the backflow prevention diode 4, and accumulates charge in the capacitor 3. Then, the FET switch 6 is brought into a connected state. The other side further passes through the backflow prevention diode 12 to rotate the blower fan 1, and at the same time supplies electricity to the charger 9 to put the storage battery 9 in a charged state through the backflow prevention diode 14.

Next, consider the case when the main switch is disconnected. The voltage from the main DC power supply 10 becomes approximately 0V, and the charger 9 also stops. Then, when the surrounding potential drops below the storage battery 8, a closed circuit is formed with the storage battery 8 → backflow prevention diode 13 → blower fan 1 → FET switch 6 → storage battery 8, and the blower fan 1 comes to be driven by the storage battery 8. . At the same time, the output of the regulator 7 also disappears, so the charge that has been stored in the capacitor 3 is discharged through the resistor 2. At the same time, the gate voltage of the FET switch 6 also decreases and when it becomes below the cutoff voltage, the FET switch is turned off and the blower fan 1 is stopped.

[0009]

[Other Embodiments] FIG. 2 shows a second embodiment in which a blower fan 1 for cooling an image forming apparatus is fixed to a fan shaft 21. The motor 22 rotates the cooling fan 1. A clutch 20 connected to a fan shaft 21 is also provided within the motor frame. Since the rotor of the motor 22 is directly attached to the cooling fan shaft 21, air flow is forcibly generated according to the rotation of the motor. The fan shaft 21 and the flywheel shaft 23 are connected via a clutch 20. The flywheel shaft 23 is coaxial with the fan shaft 21, is rotatably supported by a bearing (not shown), and has a flywheel 24 fixed to its end.

Next, the clutch 20 will be explained. Figure 3
A ratchet wheel 33 as shown in FIG. 1 is fixed to the fan shaft 21. The ratchet wheel 33 does not engage clockwise, but is tilted counterclockwise. A cylindrical outer shaft 30 is disposed coaxially with the ratchet wheel 33 and spaced apart in the radial direction. The outer shaft 30 is fixed to the flywheel shaft 23. A fin 31 is pivotally attached to the inner periphery of the outer shaft 30. The fins 31 are elastically attached to the outer shaft 30 so as to maintain the position shown in the figure, or the base side of the fins 31 is made of a flexible material and is rigidly connected to the outer shaft 30, and the fins 31 are fixed in the direction of arrow A in the figure. When the tip is displaced toward the center, it engages with the ratchet wheel 33. A fan shaft 21 is inserted into one end plate of a sealed case 35 that houses an outer shaft 30, fins 31, and a ratchet wheel 33, and a flywheel shaft 23 is inserted into the other end of the closed case 35 in a sealed manner. It is desirable that the distance between both end plates of the case 35 and the axial widths of the outer shaft 30, the fins 31, and the ratchet wheel 33 be equal. Case 3
5 is filled with a viscous liquid energy transmission medium 34.

In this clutch 20, the clockwise rotational force from the motor 22 is transferred to a medium 34 in the gap between the ratchet wheel 33 and the outer shaft 30.
is transmitted to the flywheel 24 via the motor 2.
2 becomes slower than the flywheel 24, the outer shaft 30 at the tip of the flywheel shaft 23 rotates clockwise relative to the ratchet wheel 33, causing the fins 31 to move toward the shaft center due to the fluid resistance of the liquid medium. It has a structure in which it rotates and is caught on the ratchet wheel 33, and directly transmits the rotational force of the flywheel 24 to the motor 22. Assuming that the main switch is connected now, initially the flywheel 2 will
Since the mass of flywheel 4 is heavy, inertia acts and the flywheel 24 does not try to rotate, and the clutch 20 absorbs the difference in rotation with the motor 22. However, due to the viscosity of the medium 34, the flywheel 24 eventually begins to rotate and gradually approaches the rotational speed of the motor 22, and the flywheel 24 rotates at a rotational speed slower than the fan shaft 21 due to the inherent slippage of the clutch 20. Subsequently, when the main switch of the device is turned off, the motor 22 that was driving the blower fan 1 loses its driving force and gradually attempts to reduce its rotational speed. However, since the flywheel 24 tends to continue rotating with large inertia, its rotational force is transmitted to the blower fan 1 via the fan shaft 21 by the action of the clutch 20. In this way, the cooling fan 1 can be rotated for a certain period of time even after the main switch of the device is turned off.

0012

[Effects of the Invention] As explained above, even after the main switch of the device is disconnected, the heat source is stopped by rotating the blower fan, so it is possible to efficiently prevent heat buildup, and even after the main switch is disconnected, the heat source is stopped. Temperature rises or sustained high temperatures are eliminated, improving the reliability of the equipment. Furthermore, the waiting time for maintenance, which requires waiting for the equipment to cool down before starting maintenance after turning off the main switch during maintenance, is shortened, improving maintainability. can also be improved.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram when the present invention is implemented.

FIG. 2 is a side view showing another embodiment.

FIG. 3 is an axis-perpendicular cross-sectional view of the clutch portion.

FIG. 4 is a longitudinal cross-sectional view of the image recording device.

[Explanation of symbols]

1　Blower fan 2 Resistor for determining time constant 3 Capacitor for time constant determination 6 FET switch 8 Storage battery 9 Charger 10 Main DC power supply 20 Clutch 24 Flywheel

Claims (1)

[Claims] Claim 1: An image forming device having an internal image forming means equipped with a heat source that generates heat when the main power source is turned on, and a cooling fan that is operated to cool the inside of the device when the main power source is turned on. An image forming apparatus characterized in that the image forming apparatus includes a device that rotates the cooling fan for a certain period of time after the main power source is cut off.