JPH1138808A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently eliminate radiant heat originated from a fixing unit, in an electrophotographic device of compact type transporting transfer material in the approximately vertical direction, by arranging the fixing unit on the upper part of an image forming unit. SOLUTION: This device is constituted by mounting a ventilating device consisting of an intake duct 11 and the exhaust duct 13 between the image forming unit and the fixing unit 7. The intake duct 11 and the exhaust duct 13 is respectively arranged on a photoreceptor 2 side with respect to a transporting route 8 of the transfer material, and an air curtain C is formed between the image forming unit and the fixing unit 7 in the process that air coming out from an inside intake port 11a of the intake duct 11 is discharged from the inside discharge port 13a of the exhaust duct 13. The radiant heat of the fixing unit 7 is efficiently eliminated by this air curtain C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a copying machine and a printer, and more particularly to a compact type electrophotographic apparatus in which a fixing device is arranged above an image forming unit and a transfer material (paper) is conveyed substantially vertically. The present invention relates to a heat radiation technique in an electrophotographic apparatus.

[0002]

2. Description of the Related Art In an electrophotographic apparatus, charging, exposure (light writing), transfer / separation, cleaning,
It is equipped with electrophotographic process equipment such as static elimination. Also,
The paper feeding and conveying system includes a large number of transfer material conveying rollers, and a fixing device that heats and fixes unfixed toner on the transfer material between the paper discharge unit and the transfer unit. In addition, a plurality of motors for driving each of the above-described devices and a power supply thereof are installed in the apparatus main body. As described above, the electrophotographic apparatus has a heat source such as a power supply, a motor, and a fixing device. When the apparatus is in operation, the internal temperature increases. In addition, when operated continuously for a long time, the temperature rise is more severe. When the temperature rise is remarkable, problems such as failure of components and generation of abnormal images have been caused.

Conventionally, this problem has been dealt with by providing a plurality of fans or ducts near the place where heat is to be removed and flowing air. For example, Japanese Patent Application Laid-Open No. 4-511
No. 79 proposes a technique in which air is blown from the upstream side or the downstream side of the fixing device to the non-sheet passing portion of the fixing roller. Japanese Patent Application Laid-Open No. 4-337750 proposes a technique in which air is taken between an image forming unit and a fixing device by two fans and a duct.

[0004]

By the way, the size of the machine has recently been reduced due to market requirements. As described above, the fixing device is arranged above the image forming unit, and the transfer material (paper) is substantially reduced. A compact type electrophotographic apparatus that transports vertically is commercially available. In such an electrophotographic apparatus, each unit is small, and a space between them is also narrow. The space between the image forming unit and the fixing device is no exception. For this reason, the radiant heat generated in the fixing device heats the image forming unit, causing problems such as abnormal images and toner blocking.

In order to prevent such abnormalities due to heat, it is necessary to efficiently remove radiant heat from the fixing device. that time,
It is difficult to secure the air flow path and the space for installing the fan in a narrow space.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and in a compact type electrophotographic apparatus in which a fixing device is disposed above an image forming unit and which conveys a transfer material in a substantially vertical direction, a fixing device is used. The purpose is to efficiently remove radiant heat.

[0007]

According to a first aspect of the present invention, a fixing device is provided above an image forming unit including a photoreceptor and an electrophotographic process device disposed around the photoreceptor. In an electrophotographic apparatus in which the transfer material is transported substantially vertically, between the image forming unit and the fixing device,
An intake duct with an internal intake port at the downstream end in the suction direction and an exhaust duct with an internal exhaust port at the upstream end in the exhaust direction open on the side facing the toner image of the transfer material. It is characterized in that the lower side and the inner side of the exhaust duct are stacked so that the inner outlet of the exhaust duct is on the upper side.

According to a second aspect of the present invention, in the first aspect, the internal intake port of the intake duct and the internal exhaust port of the exhaust duct have a width substantially equal to the axial width of the fixing device. It is characterized by being formed in.

According to a third aspect of the present invention, a fixing device is provided above an image forming unit including a photoreceptor and an electrophotographic process device disposed around the photoreceptor, and the transfer material is transported substantially vertically. In an electrophotographic apparatus, between an image forming unit and a fixing device, an intake duct having an internal intake port at a downstream end in an adsorption direction opened on a side facing a toner image of a transfer material, and an internal exhaust port also at an upstream end in an exhaust direction. Are provided so that the internal intake port and the internal exhaust port are arranged in parallel in the axial direction of the fixing device.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the internal intake port having a width of about half the axial width of the fixing device and a width substantially the same as the internal intake port are provided. The internal discharge ports are provided in parallel.

According to a fifth aspect of the present invention, in the third aspect, one of the internal intake port and the internal discharge port is divided into a central portion in the axial direction of the fixing device, and the other is divided into a plurality of parts. It is characterized by being provided in parallel so as to surround it.

According to a sixth aspect of the present invention, in the first and third aspects of the invention, a branch duct is provided in the middle of the intake duct.

According to a seventh aspect of the present invention, in the first and third aspects of the present invention, the pressure loss of the exhaust duct is set to be smaller than the pressure loss of the intake duct.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a layout diagram of an image forming unit and a fixing device of an electrophotographic apparatus according to the present invention. The image forming unit 1 includes a photoreceptor 2 and electrophotographic process devices such as a charging roller 3, a developing device 4, a transfer roller 5, and a cleaning device 6 disposed around the photoreceptor 2. A fixing device 7 that heats and fixes an unfixed toner image on a transfer material by heating and fixing is arranged near the upper portion of the image forming unit 1. The transfer material transfer path 8 is substantially vertical.

The transfer material is conveyed from below through the conveyance path 8 and comes into contact with the photoreceptor 2 at the transfer portion, and the toner image formed on the photoreceptor 2 is transferred by the action of the transfer roller 5.
Thereafter, the transfer material is passed through a fixing device 7 where an unfixed toner image is fixed.

In the present invention, a ventilation device including an intake duct and an exhaust duct is installed between the image forming unit 1 and the fixing unit 7 shown in FIG. 1, and an air curtain is formed between the image forming unit 1 and the fixing unit 7. By doing so, the radiant heat of the fixing device 7 is prevented from being transmitted to the image forming unit 1.

FIG. 2 is a front view of the installation state of the ventilation device according to the first embodiment. The image forming unit 1 and the fixing device 7 include an intake duct 11 having an intake fan 12 provided at an outer opening and an exhaust duct 13 having an exhaust fan 14 provided at an outer opening.
Installed between Specifically, the intake duct 11 is on the lower side,
The two are stacked so that the exhaust duct 13 is on the upper side, and the downstream end of the intake duct 11 (the intake fan 1
On the internal intake port 11a at the end opposite to the end at which the exhaust fan 2 is attached), the upstream end of the exhaust duct 13 in the exhaust direction (the end opposite to the end at which the exhaust fan 14 is attached) is placed. The internal outlets 13a are overlapped.

Here, when the exhaust duct 13 is superimposed on the intake duct 11, the internal exhaust port 13a of the exhaust duct 13 usually overlaps the internal intake port 11a of the intake duct 11, but this will be described later. As shown in the embodiment, the internal intake port 11a and the internal exhaust port 13a may be arranged in parallel in the axial direction while the exhaust duct 13 is placed above the intake duct 11, so that the internal intake port 11a may be distinguished from the internal intake port 11a. And the positional relationship between the internal discharge port 13a.

The stacked internal intake port 11a and internal discharge port 13a face the toner image on the transfer material.
In other words, the intake duct 11 and the exhaust duct 13 are provided on the same side as the photoconductor 2 with respect to the transport path 8. In addition, both the intake fan 12 and the exhaust fan 14
It may be in the middle of steps 1 and 13. In addition, both fans 12,
14 may have the same size or different sizes.

In such a configuration, the intake fan 12
Rotates, the outside air flows through the intake duct 11 with an arrow A
It flows in the direction and is sprayed between the image forming unit 1 and the fixing device 7 from the internal intake port 11a. Then, it turns into the exhaust duct 13 through the internal exhaust port 13a, is transported in the direction of arrow B by the action of the exhaust fan 14, and is exhausted to the outside. In this series of air flows, an air curtain indicated by an arrow C is formed between (the cleaning device 6 of) the image forming unit 1 and the fixing device 7, and thereby the fixing device 7 is formed.
The radiant heat generated in the above can be removed.

FIG. 3 is a perspective view showing an installation state of the ventilation device according to the second embodiment. In the first embodiment shown in FIG. 2, the outside openings of the intake duct 11 and the exhaust duct 13 are overlapped with each other, but they may be turned at right angles to each other as shown in FIG. In short, the intake fan 12
It is sufficient that the air taken into the intake duct 11 forms an air curtain C and is exhausted to the outside by the exhaust fan 14.

FIG. 4 is a perspective view showing a state of installation of a ventilating apparatus according to a third embodiment, FIG. 5 is a perspective view of an exhaust duct, FIG. 6 is a perspective view of a paper feed duct, and FIG. It is a figure which shows the flow of air.

In the third embodiment, the internal intake port 11a of the intake duct 11 and the internal exhaust port 1 of the exhaust duct 13
Reference numerals 3a each have a width substantially the same as the width of the fixing device 7 in the axial direction. By doing so, there is no temperature unevenness in the axial direction, and heat can be uniformly removed from the entire space between the fixing device 7 and the cleaning device 6. In this case, air is taken in from the lower intake duct 11 and
However, the intake and exhaust may be upside down. Further, the internal intake port 11a and the internal discharge port 13a do not need to be aligned on the same plane, and may have a slight angle between them as shown in FIG.

FIG. 8 is a perspective view of a ventilation device according to a fourth embodiment in an installed state, FIG. 9 is a perspective view of the ventilation device alone,
FIG. 10 is a perspective view of the intake duct, and FIG. 11 is a perspective view of the exhaust duct.

In the fourth embodiment, while the exhaust duct 13 is placed on the intake duct 11,
a and the internal discharge port 13a are made horizontal in the axial direction of the fixing device 7. More specifically, as shown in FIGS. 8, 9 and 10, the intake duct 11 is divided into two parts inward, and two internal intake ports 11a, 11a are provided at distant positions.
8 and 9, as shown in FIGS.
The internal discharge port 13a is located between them.
With this configuration, as shown in FIG. 9, air flows horizontally from the intake duct 11 to the exhaust duct 13, and an air curtain C is formed between the fixing device 7 and the photoconductor 2. The generated radiant heat can be cut off. In this case,
Since the internal intake port 11a and the internal discharge port 13a are horizontal, even when the distance between the fixing device 7 and the photosensitive member 2 is extremely narrow, the internal intake port 11a and the internal exhaust port 13a You can get in between.

FIG. 12 is a perspective view of a ventilation device alone showing a modification of the fourth embodiment. In this example, the internal intake port 11a of the intake duct 11 is set so that the air flow from the intake duct 11 to the exhaust duct 13 becomes smoother.
Are provided at an angle θ at the corners of.

FIG. 13 is a perspective view of a ventilating apparatus according to a fifth embodiment. In the fifth embodiment, the intake duct 11 and the exhaust duct 13 are provided not in the vertical direction but in parallel in the horizontal direction, and the internal intake port 11a and the internal exhaust port 13a are provided.
Are also provided horizontally. Also in this case, the intake duct 1
Air flows horizontally from 1 to the exhaust duct 13 to form an air curtain C. The advantage that no space is required in the height direction is the same as that of the fourth embodiment.

FIG. 14 is a perspective view of an intake duct of a ventilation device according to a sixth embodiment. In the sixth embodiment, a branch portion 11b is provided in the middle of the intake duct 11 to reduce the flow rate on the intake side. At this time, the air flowing to the branching side can be used for cooling a heat source other than the fixing device 7 such as a power supply and a motor.

In addition, by forming the intake duct 11 with a shape having a large pressure loss and the exhaust duct 13 with a shape having a small pressure loss, the flow rate of the exhaust gas can be made larger than the flow rate of the intake air. Further, the pressure loss can be increased by using a filter or the like. Further, the size of the fan may be small for intake and large for exhaust, so that the flow rate of exhaust is larger than the flow rate of intake, or the rotation speed of the fan may be small on the intake side and large on the exhaust side.

In the embodiment of the present invention, the image forming unit 1
A ventilation device including an intake duct 11 and an exhaust duct 13 is installed between the fixing device 7 and the fixing device 7. The intake duct 11 and the exhaust duct 13 are provided on the photoconductor 2 side with respect to the transfer path 8 of the transfer material, and the air that has exited from the internal intake port 11 a of the intake duct 11 is exhausted from the internal exhaust port 13 a of the exhaust duct 13. During the process, an air curtain C is formed between the image forming unit 1 and the fixing device 7. The fixing device 7 is controlled by the air curtain C.
Radiant heat is efficiently removed.

[0031]

According to the first and third aspects of the present invention, the photosensitive member is prevented from being heated by the radiant heat of the fixing device by forming an air curtain between the fixing device and the image forming unit. can do.

According to the second aspect of the present invention, heat can be evenly removed from the entire portion between the fixing device and the image forming unit.

According to the third, fourth, and fifth aspects of the present invention, even when the space between the fixing device and the image forming unit is narrow, the installation space for the internal intake port and the internal discharge port is ensured, and the fixing device is provided. Air can flow between and the imaging unit.

According to the sixth and seventh aspects of the present invention, the air taken in between the fixing device and the image forming unit can be smoothly discharged without stagnating at that portion. Further, it is possible to prevent high-temperature air between the fixing device and the image forming unit from leaking to other portions.

[Brief description of the drawings]

FIG. 1 is a layout diagram of an image forming unit and a fixing device of an electrophotographic apparatus according to the present invention.

FIG. 2 is a front view of an installation state of the ventilation device according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing an installation state of a ventilation device according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing an installation state of a ventilation device according to a third embodiment of the present invention.

FIG. 5 is a perspective view of the exhaust duct.

FIG. 6 is a perspective view of the intake duct.

FIG. 7 is a diagram showing a flow of air.

FIG. 8 is a perspective view illustrating a state in which a ventilation device according to a fourth embodiment of the present invention is installed.

FIG. 9 is a perspective view of the ventilation device alone.

FIG. 10 is a perspective view of the intake duct.

FIG. 11 is a perspective view of the exhaust duct.

FIG. 12 is a perspective view of a ventilator alone showing a modification of the fourth embodiment of the present invention.

FIG. 13 is a perspective view of a ventilator alone showing a fifth embodiment of the present invention.

FIG. 14 is a perspective view of an intake duct of a ventilation device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Photoreceptor 3 Charging roller 4 Developing device 5 Transfer roller 6 Cleaning device 7 Fixing device 8 Transport path 11 Intake duct 11a Internal intake port 11b Branch 12 Intake fan 13 Exhaust duct 13a Internal exhaust port 14 Exhaust fan A Intake Flow of air taken into duct 11 B Flow of air exhausted from exhaust duct 13 C Air curtain

Claims (7)

[Claims] 1. An electrophotographic apparatus having a fixing unit above an image forming unit including a photoreceptor and an electrophotographic process device disposed around the photoreceptor, wherein a transfer material is transported substantially vertically. Between the unit and the fixing device, an intake duct in which the internal intake port at the downstream end in the suction direction opens on the side facing the toner image of the transfer material, and an exhaust duct in which the internal exhaust port also opens at the upstream end in the exhaust direction, An electrophotographic apparatus, wherein an internal intake of an intake duct is provided on a lower side, and an internal exhaust of an exhaust duct is provided on an upper side. 2. The apparatus according to claim 1, wherein the internal intake of the intake duct and the internal exhaust of the exhaust duct are formed to have a width substantially equal to the axial width of the fixing device. Electrophotographic equipment. 3. An electrophotographic apparatus having a fixing device above an image forming unit including a photoreceptor and an electrophotographic process device disposed around the photoreceptor, and in which a transfer material is transported substantially vertically. Between the unit and the fixing device, an intake duct in which the internal intake port at the downstream end in the suction direction opens on the side facing the toner image of the transfer material, and an exhaust duct in which the internal exhaust port also opens at the upstream end in the exhaust direction, An electrophotographic apparatus, wherein an internal intake port and an internal discharge port are provided so as to be arranged in parallel in the axial direction of the fixing device. 4. The fixing device according to claim 3, wherein an internal intake having a width of about half the axial width of the fixing device and an internal exhaust having substantially the same width as the internal intake are provided in parallel. An electrophotographic apparatus, characterized in that: 5. The fixing device according to claim 3, wherein one of the internal intake port and the internal discharge port is provided in a central portion in the axial direction of the fixing device, and the other is divided into a plurality and provided in parallel so as to surround the same. An electrophotographic apparatus characterized by the following. 6. The electrophotographic apparatus according to claim 1, wherein a branch duct is provided in the middle of the intake duct. 7. The electrophotographic apparatus according to claim 1, wherein the pressure loss of the exhaust duct is set to be smaller than the pressure loss of the intake duct.