JP2003156990A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance profitability by reducing the numbers of air sending fans and air sending ducts in an image forming apparatus. SOLUTION: This image forming apparatus has a device main body, an image forming means having a photoreceptor provided at the inside of the device main body, an electrifying device to electrify the surface of the photoreceptor, an exposure unit to form an electrostatic latent image on the surface of the photoreceptor, a developing unit to form a toner image by developing the electrostatic latent image on the surface of the photoreceptor and a transfer unit to transfer the toner image on the surface of the photoreceptor to recording paper, the air sending fan provided at the inside of the device main body and to discharge air at the inside of the device main body to the outside of the device main body, the air sending duct to guide the air sent from the air sending fan to the outside of the device main body, a filter which is provided at the air sending duct and through which the air flowing through the air sending duct passes and a power source unit having a power source circuit element and a heat sink and provided at the inside of the device main body in a state in which the heat sink is projected to the inside of the air sending duct.

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.

[0002]

2. Description of the Related Art An image forming apparatus adopting an electrophotographic system forms an image on a recording sheet by an image forming means provided inside an apparatus main body. That is, the surface of the photoconductor drum is charged by the charger, the surface of the photoconductor drum is exposed by the exposure device to form an electrostatic latent image, and then the electrostatic latent image on the surface of the photoconductor drum is formed by the developing device. After development, a toner image is formed, then the toner image on the surface of the photosensitive drum is transferred to a recording paper by a transfer device, and the toner image transferred to the recording paper is fixed by a fixing device.

As the charging device, a charging device of the type which charges by corona discharge is generally used. In this type of charger, ozone is generated by the discharging action. This ozone is harmful and needs to be filtered out. Therefore, inside the device body, a blower fan that sends the air inside the device body to the outside, a blower duct that guides the air sent from the blower fan to the outside of the device body, and a blower duct provided on this blower duct are provided. And a filter through which the flowing air passes. Ozone contained in the air is removed by driving a blower fan to allow the air containing ozone inside the apparatus main body to pass through the filter, and then the air is sent to the outside of the apparatus main body through the blower duct.

Further, a power supply unit having a power supply circuit element such as a power transistor is independently provided inside the main body of the apparatus. Since the power supply circuit element generates heat in this power supply unit, it has a heat sink that dissipates this heat to the outside. In order to dissipate the heat dissipated by the heat sink from the main body of the device, a blower fan and a blower duct dedicated to the power supply unit are provided in the vicinity of the power supply unit, and the blower fan is driven to blow air near the power supply unit. The heat generated in the power supply unit is discharged to the outside of the main body of the apparatus by sending the heat to the outside of the main body of the apparatus.

[0005]

In such a conventional image forming apparatus, in order to remove the ozone in the air inside the apparatus main body and send it to the outside of the apparatus main body, and to discharge the heat of the power supply unit to the outside of the apparatus main body. Each has its own blower fan. Therefore, a large number of air-blowing fans are installed as an image forming apparatus, and a large number of air-blowing ducts are required to provide air-blowing ducts attached to each air-blowing fan, resulting in high facility cost and poor economy. There is.

According to the present invention, one blower fan discharges the air inside the apparatus body to the outside and the heat of the power supply unit is discharged to the outside of the apparatus body, and the number of blower fans and blower ducts is increased. It is an object of the present invention to provide an image forming apparatus with reduced cost and improved economy.

[0007]

According to another aspect of the present invention, there is provided an image forming apparatus, an apparatus main body, a photoconductor provided inside the apparatus main body, a charger for charging the surface of the photoconductor, and the photoconductor. An exposure device that exposes the surface to form an electrostatic latent image, a developing device that develops the electrostatic latent image on the surface of the photoconductor to form a toner image, and a toner image on the surface of the photoconductor is transferred to recording paper Image forming means having a transfer device, a blower fan provided inside the apparatus body for sending air inside the apparatus body to the outside of the apparatus body, and air sent from the blower fan for the apparatus body. A blower duct that leads to the outside, a power supply circuit element, and a heat sink that dissipates the heat generated by the power supply circuit element, and a power supply unit that is provided inside the apparatus body with the heat sink inserted inside the blower duct. Characterized by comprising.

According to the structure of the present invention, the air inside the main body of the apparatus is removed of ozone by the single blower fan and is sent to the outside, and the heat of the power supply unit is discharged to the outside of the main body of the apparatus to blow air. The number of fans and air ducts can be reduced.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the power supply unit projects to a unit case, a power supply circuit element provided inside the unit case, and the outside of the unit case. A heat sink is provided, and the unit case constitutes a part of a wall portion of the blower duct.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the blower duct is provided with a filter for removing ozone contained in the air flowing through the blower duct. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

This embodiment is intended for an in-body sheet discharging type image forming apparatus. FIG. 1 is a cross-sectional view schematically showing the image forming apparatus according to this embodiment, and FIG. 2 is an enlarged cross-sectional view showing a portion provided with a ventilation duct and a power supply unit of the image forming apparatus according to this embodiment.

In FIG. 1, reference numeral 1 denotes an apparatus main body of this image forming apparatus. An image reading section 2 is provided on an upper stage of the apparatus main body 1, and a cassette 3 for accommodating recording sheets P in a stacked manner is provided on a lower stage thereof. A paper discharge space 4 is provided in the middle section.

Inside the apparatus main body 1, means for forming an image on a recording paper is provided. That is, the photoconductor drum 11 inside the apparatus main body 1, a charger 12 that charges the surface of the photoconductor drum 11, an exposure device 13 that exposes the surface of the photoconductor drum 11 to form an electrostatic latent image, and a photoconductor. Drum 11
Developing device 14 that develops the electrostatic latent image on the surface of to form a toner image, transfer device 15 that transfers the toner image on the surface of photoconductor drum 11 onto recording paper, and the toner image transferred onto the recording paper is fixed. A fixing device 16 is provided. The charger 12 is of a type that charges by using corona discharge.

Then, the photoconductor drum 1 is charged by the charger 12.
The surface of 1 is charged, then the surface of the photosensitive drum 11 is exposed by the exposure device 13 to form an electrostatic latent image, and then the electrostatic latent image on the surface of the photosensitive drum 11 is developed by the developing device 14. Form a toner image. On the other hand, the recording paper P is delivered from the cassette 3 and is conveyed between the photoconductor drum 11 and the transfer device 12. Next, the transfer device 15 transfers the toner image on the surface of the photosensitive drum 11 onto the recording paper P, and the fixing device 16
Thus, the toner image transferred onto the recording paper P is fixed. The recording paper P on which the toner image is fixed is discharged to the paper discharge space 4 of the apparatus main body 1.

Inside the apparatus body 1, the apparatus body 1
A blower fan 21 for discharging the air inside the apparatus main body 1 to the outside, a blower duct 22 for guiding the air sent from the blower fan 21 to the outside of the apparatus main body 1, and this blower duct 2
2 is provided with a filter 23 through which the air flowing through the blower duct 22 passes. That is, the air duct 2
2 is horizontally provided between the blower fan 21 and an opening formed in, for example, a side surface of the apparatus body 1.

Since the charger 12 is of a type that charges by corona discharge, ozone is generated by the discharge action. This ozone is harmful. Therefore, by removing ozone from the air of the apparatus body 1 containing the ozone, the apparatus body 1
The blower fan 21, the blower duct 22 and the filter 23 are provided for discharging the air to the outside of the.

Further, a power supply unit 31 is provided inside the apparatus main body 1. The power supply unit 31 is attached to a unit case 32, a circuit board 33 provided inside the unit case 32, a heat sink 34 attached to the circuit board 33, a power transistor 35 attached to the heat sink 34, and a circuit board 33. The switching element 36 is provided. The power transistor 35 and the switching element 36 are power supply circuit elements.

The heat sink 34 is attached to the upper surface of the circuit board 33, penetrates the upper wall of the unit case 32, and projects to the outside of the unit case 32. The heat sink 34 absorbs the heat generated by the power transistor 35 and dissipates the absorbed heat to the outside of the unit case 32.

In the power supply unit 31, the unit case 32 constitutes a part of the wall portion of the blower duct 22, and the heat sink 3
4 are provided in a state of protruding inside the blower duct 22. That is, the opening 22 is formed in the lower wall of the blower duct 22.
a is formed. The power supply unit 31 is the air duct 2
2, the upper wall portion of the unit case 32 closes the opening 22a in the lower wall portion of the blower duct 22 from the outside. The unit case 32 is attached to the apparatus body 1 by a member (not shown), the unit case 32 is attached to the apparatus body 1 by a member (not shown), and the upper wall portion of the unit case 32 is the lower wall portion of the blower duct 22. And the blower duct 22 is fixed by, for example, bolts (not shown). As a result, the unit case 32 of the power supply unit 31 supports the blower duct 22 from the lower side, and the number of parts for supporting the blower duct 22 can be reduced accordingly.

The heat sink 34, which penetrates the upper wall portion of the unit case 32 and projects above the unit case 32, is formed by the blower duct 22.
Is located in the interior of the fan in a direction orthogonal to the airflow flowing through the blower duct 22. For this reason, the heat sink 34 is in a state in which the air sent by the rotational drive of the blower fan 21 and the air flowing through the blower duct 22 comes into contact.

In the image forming apparatus thus constructed, when the blower fan 21 is rotationally driven, the air inside the apparatus main body 1 passes through the filter 23, flows through the blower duct 22 and is sent out of the apparatus main body 1. It The air inside the apparatus main body 1 contains ozone generated by the corona discharge of the charger 12, but the ozone is adsorbed and removed when passing through the filter 23.

The air sent by the blower fan 21 and flowing through the blower duct 22 comes into contact with the heat sink 34 of the power supply unit 31 projecting into the blower duct 22 to remove heat from the heat sink 34 to remove the heat from the apparatus body 1. It is sent to the outside. Therefore, the heat that is dissipated by the heat sink 34 due to the air flowing through the blower duct 22 can be effectively discharged to the outside of the apparatus body 1. This is the same operation as that of the related art in which a dedicated blower fan is provided for radiating heat from the power supply unit, and air is blown by driving this blower fan to discharge the heat dissipated by the heat sink of the power supply unit to the outside of the apparatus main body 1. Therefore, the combination of one blower fan 21 and blower duct 22 removes the ozone contained in the air inside the device body 1 and sends it to the outside of the device body 1 and the heat generated by the power supply unit 31. Both can be discharged to the outside of the apparatus main body 1. Therefore, it is possible to eliminate the conventional fan provided for radiating the power supply unit and the air duct connected to the fan, which simplifies the configuration of the equipment installed in the image forming apparatus and reduces the equipment cost. it can.

Further, since the unit case 32 of the power supply unit 31 constitutes a part of the wall portion of the blower duct 22, the airflow flowing through the blower duct 22 touches the unit case 32 to remove the heat of the unit case 32 and remove the heat from the unit case 32. 32
Can be cooled. Therefore, the power supply unit 31
It is possible to more effectively discharge the heat generated from the outside of the apparatus main body 1.

The present invention is not limited to the above-described embodiments, but can be modified in various ways.

[0026]

According to the image forming apparatus of the first aspect of the present invention, the air inside the apparatus main body is sent to the outside by one blower fan, and the heat of the power supply unit is discharged to the outside of the apparatus main body. Both can be done to reduce the number of blast fans and blast ducts to improve economics.

According to the second aspect of the present invention, the heat generated from the power supply unit can be more effectively discharged to the outside of the apparatus main body.

According to the third aspect of the present invention, ozone generated inside the apparatus body can be removed when the air inside the apparatus body is sent to the outside.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a portion provided with a ventilation duct and a power supply unit of the image forming apparatus according to the embodiment.

[Explanation of symbols]

1 ... Device body 11 ... Photosensitive drum 21 ... Blower fan 22 ... Blower duct 23 ... Filter 31 ... Power supply unit 32 ... Unit case 33 ... Circuit board 34 ... Heat sink

Claims (3)

[Claims] 1. An apparatus main body, a photoconductor provided inside the apparatus main body, a charger for charging the surface of the photoconductor, an exposure device for exposing the surface of the photoconductor to form an electrostatic latent image, An image forming unit having a developing device for developing an electrostatic latent image on the surface of the photoconductor to form a toner image, a transfer device for transferring the toner image on the surface of the photoconductor to a recording sheet, and the inside of the apparatus main body. A blower fan for sending the air inside the device body to the outside of the device body, and a blower duct for guiding the air sent from the blower fan to the outside of the device body,
A power supply circuit element and a heat sink for dissipating heat generated by the power supply circuit element, and a power supply unit provided inside the apparatus main body in a state where the heat sink is inserted inside the blower duct. Image forming apparatus. 2. The power supply unit is a unit case,
The power supply circuit element provided inside the unit case and a heat sink protruding outside the unit case, and the unit case constitutes a part of a wall portion of the air duct. The image forming apparatus according to item 1. 3. The image forming apparatus according to claim 1, wherein the blower duct is provided with a filter for removing ozone contained in the air flowing through the blower duct.