JPH08328410A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device for preventing heat discharged from a heating body for a fixing means from being diffused in a device main body without increasing the rotating speed of a fan. CONSTITUTION: This device is provided with a fixing device 15 for making a paper P with a toner image formed by an image forming means K pass through, heating and pressing the paper P so as to fix the toner image on the paper P, a cover 19 for covering the outer peripheral part of a heat roller 21 for the fixing device 15 and also provided with an introducing port for the paper P, placed opposite to an upper housing with leaving a space 32 between the upper housing and the cover, a partition member 33 for partitioning the space 32 installed on the introducing port of the cover 19 so as to project toward the outside, and a guide part 34 installed on the partitioning member 33 and guiding the paper P to the introducing port along the guide surface 34a.

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 applied as an electrophotographic apparatus, for example.

[0002]

2. Description of the Related Art FIG. 1 shows a part of the internal structure of an electrophotographic apparatus. Reference numeral 101 in the drawing denotes a photoconductor as an image carrier. A charging charger 102, an exposure unit 103, a developing device 104, a transfer charger 105, and a peeling charger 1 are provided around the photosensitive member 101 along the rotation direction thereof.
06 and the cleaning device 107 are sequentially arranged.

During image formation, the laser beam is scanned by the rotation of the polygon mirror 108, and is irradiated onto the surface of the photoconductor 101 through an optical system. The surface of the photoconductor 101 is charged by the charging charger 102, and the charged surface is irradiated with the above-mentioned light to form an electrostatic latent image corresponding to the original image. This electrostatic latent image is sent to the developing device 104 by the rotation of the photoconductor 101, and visualized by the toner supplied from the developing device 104.

On the other hand, at this time, paper is supplied from a paper feed cassette (not shown), and this paper is sent to the image transfer portion between the photoconductor 101 and the transfer charger 105,
By the action of the transfer charger 105, the photoconductor 101
The upper toner image is transferred. The paper P on which the toner image is transferred is operated by the peeling charger 105 to cause the photosensitive member 1
After being peeled off from 01, the image is sent to the fixing device 110 to fix the image, and the image is discharged to the outside of the main body of the device.

FIG. 6 shows a fixing device 110. The fixing device 110 has a heat roller 111 which is heated to about 200 ° C. to fix the toner to the paper P and a press roller which is in pressure contact with the heat roller 111. It consists of 112.

The sheet P on which the toner image has been transferred at the image transfer section is conveyed by the traveling of the conveyor belt 113 and is sent between the heat roller 102 and the press roller 103 to heat the image. It is pressed and fixed.

By the way, the fixing device 110 when the copying machine is used
The outline of the flow of heat around is as shown by the arrow in FIG. 1, but the heat radiation from the heat roller 111 is a major factor, and the photoconductor is a cylindrical metal for copying the characters of the original with toner. There is a possibility that the surface temperature of 101 may rise above the standard and deteriorate the performance.

In order to prevent this, the heat roller 111
The outer peripheral portion of is covered with a plastic cover 115. Further, the heat is dissipated to the outside by the rotation of the fan 114 for sucking the paper, which is provided on the lower side of the transport belt 115 for transporting the paper P to the fixing device 101.

[0009]

However, the method of releasing the heat by rotating the fan 114 is the fan 114.
If the number of rotations is increased, the paper is violated on the conveyor belt 113, so that the number of rotations cannot be increased so much, and there is a disadvantage that the cooling function is limited.

Further, as shown in FIG. 6, when a type of paper having a large upward curl (the property that the paper is bent) is used, the leading edge of the paper is introduced into the paper introducing port 116 of the cover 115 with respect to the conveying direction. However, there is the inconvenience that the phenomenon of paper jam cannot be prevented because it faces in the opposite direction and breaks when entering.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus in which the heat emitted from the heating body of the fixing unit is not diffused into the apparatus body without increasing the rotation speed of the fan. To do.

[0012]

In order to solve the above-mentioned problems, the present invention provides a device main body comprising an upper and lower housing which can be opened and closed, and a medium provided in the device main body. An image forming means for forming a developer image on the lower body, a heating body provided in the lower housing, and a pressing body rollingly contacting the heating body, and the image forming means between the heating body and the pressing body. Fixing means for heating and pressurizing the medium by passing the medium on which the developer image is formed by the fixing means for fixing the developer image on the medium, and covering the outer peripheral portion of the heating body of the fixing means and A cover that faces the upper housing with a gap and has an inlet port for the medium, a partition member protruding outward from the inlet port of the cover to partition the gap, and the partition member. It is provided on the member, and the medium is guided along the guide surface. Formed by and a guide portion for guiding the inlet portion Te.

According to a second aspect of the present invention, there is provided an apparatus main body including upper and lower casings which can be freely opened and closed, an image forming means for forming a developer image on a medium provided in the apparatus main body, and the lower casing. A heating body and a pressure body that is in contact with the heating body, and the medium on which the developer image is formed by the image forming means is passed between the heating body and the pressure body. The fixing means for heating and pressing the developer image to fix the developer image on the medium, and the heating means of the fixing means to cover the outer peripheral portion of the fixing means and to face the medium with a gap therebetween. A cover having an introduction port portion, and a partition member having a low heat emissivity, which is provided at the introduction port portion of the cover so as to project outward and partition the gap, and the partition member is provided with the medium along the guide surface. And a guide part that guides the inside of the inlet. Equipped and composed.

According to a third aspect of the present invention, there is provided an apparatus main body including upper and lower housings which can be freely opened and closed, an image forming means for forming a developer image on a medium provided in the apparatus main body, and the lower housing. A heating body and a pressure body that is in contact with the heating body, and the medium on which the developer image is formed by the image forming means is passed between the heating body and the pressure body. The fixing means for heating and pressing the developer image to fix the developer image on the medium, and the heating means of the fixing means to cover the outer peripheral portion of the fixing means and to face the medium with a gap therebetween. A cover having an introduction port portion, a partition member that projects outwardly at the introduction port portion of the cover to partition the gap, and is provided on one surface side of the partition member, the medium along the guide surface. A guide portion that guides the inside of the inlet, Formed by and a provided on the other side insulation cutting member.

According to a fourth aspect of the present invention, there is provided an apparatus main body composed of upper and lower casings which can be opened and closed, an image forming means for forming a developer image on a medium provided in the apparatus main body, and the lower casing. A heating body and a pressure body that is in contact with the heating body, and the medium on which the developer image is formed by the image forming means is passed between the heating body and the pressure body. The fixing means for heating and pressing the developer image to fix the developer image on the medium, and the heating means of the fixing means to cover the outer peripheral portion of the fixing means and to face the medium with a gap therebetween. A cover having an introduction port portion, a partition member protruding outward at the introduction port portion of the cover to partition the gap, and a guide surface provided on this partition member and having an arc-shaped guide surface for the tip portion of the medium. Guide downwards along the inlet Formed by and a guide portion for guiding the

[0016]

According to the present invention, the gap between the cover of the fixing means and the upper casing is partitioned by the partition member, and the medium is guided into the paper introduction port by the guide portion of the partition member. Thus, the heat released from the cover of the fixing unit to the gap can be blocked to prevent the heat from widely flowing into the main body of the apparatus, and the medium can be prevented from being jammed in the paper inlet.

According to the second aspect of the present invention, the partition member is made of a metal material having a low heat radiation property, so that the heat radiated from the fixing means can be blocked more reliably.

According to the third aspect of the present invention, by providing the partition member with a heat insulating material, the heat radiated from the fixing means can be blocked more reliably. According to a fourth aspect of the present invention, an arcuate guide surface is formed on the guide portion of the partition member, and the guide surface guides the leading end portion of the medium downward and guides it into the introduction port portion. The medium can be introduced into the introduction port.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS. FIG. 2 shows an image forming apparatus such as a printer or a copying machine. In the figure, 1 is an apparatus main body. The device body 1 is of a clamshell type and is composed of upper and lower housings 1A and 1B that can be opened and closed.

FIG. 3 shows a part of the internal structure of the image forming apparatus. In the figure, 2 is a rotatable photosensitive drum as an image carrier. Around the periphery of the photosensitive drum 2, along the rotation direction thereof, the charging charger 3, the exposure unit 4,
Developing device 5, transfer charger 6, peeling charger 7
And the cleaning device 8 is sequentially arranged.

A laser optical system 9 is provided on the upper side of the apparatus body 1. The laser optical system 9 includes a rotatable polygon mirror 10 for scanning laser light sent from a semiconductor laser (not shown), an optical lens 11 for passing laser light scanned by rotation of the polygon mirror 10, and an optical lens The reflection mirrors 12 and 13 reflect the laser light that has passed through the lens 11 and guide it to the photosensitive drum 2.

A sheet conveying path 14 is provided on the lower side of the apparatus main body 1, and the transfer charger 6, the peeling charger 7, and the conveying belt are sequentially provided in the conveying path 14 in the sheet conveying direction. 16 and the fixing device 15 are provided.

A fan 1 is provided below the conveyor belt 16.
8 is provided, and the rotation of the fan 18 sucks the paper onto the conveyor belt 16. Then, at the time of image formation, laser light is emitted from the semiconductor laser to the polygon mirror 10, and the laser light is scanned by the rotation of the polygon mirror 10. The scanned laser light is imaged on the surface of the photosensitive drum 2 via the optical lens 11 and the reflection mirrors 12 and 13. The surface of the photosensitive drum 2 is charged by the charging charger 3, and the charged surface is irradiated with the above-mentioned light, whereby an electrostatic latent image corresponding to the original image is formed. This electrostatic latent image is sent to the developing device 5 by the rotation of the photosensitive drum 2 and visualized by the toner supplied from the developing device.

On the other hand, at this time, a sheet is supplied from a sheet feeding cassette (not shown), the sheet is sent to an image transfer portion between the photoconductor drum 2 and the transfer charger 6, and by the action of the transfer charger 6. The toner image on the photosensitive drum 2 is transferred. The sheet on which the toner image is transferred is peeled off from the photoconductor drum 2 by the action of the peeling charger 7, and then sent to the fixing device 15 to fix the image and is discharged to the outside of the apparatus main body 1.

FIG. 1 shows the fixing device 15. The fixing device 15 is a heat roller 21 (temperature is controlled to about 200 ° C.) as a heating body for melting the toner transferred on the paper P as a medium by heat.
And a press roller 22 as a pressurizing member for rolling contact with the heat roller 21 and applying a load to the toner melted by the heat roller 21 to fix the toner on the paper. An upper entrance guide 23 and a lower entrance guide 24 for accurately guiding the paper P are provided on the paper introduction side of the heat roller 21 and the press roller 22. The heat roller 21 is covered with a plastic cover 19 in order to reduce heat radiation from the heat roller 21 and for safety to the human body. A paper inlet port 19a is formed in the cover 19, and the paper is introduced into the interior through the inlet port 19a. The upper surface side of the cover 19 and the upper housing 1
A gap 32 is formed between the duct 31 on the bottom side of A so that the heat emitted from the cover 19 is not directly transmitted to the duct 31.

By the way, a partition member 33 made of a metal plate having a body heat radiating property is projectingly provided in the paper introducing port portion 19a of the cover 10 so as to project outward, and the partition member 33 partitions the gap 32. ing. A guide member 34 is attached to the lower surface side of the partition member 33, and an arc-shaped guide surface 34a is formed on the guide member 34. The guide member 34 is located on an extension line of the guide member 23 on the inner side, and can guide the paper P toward the guide member 23.

A heat insulating material 35 may be attached to the upper surface of the partition member 33. As the heat insulating material 35, for example, glass wool on which an aluminum foil having a small thermal emissivity is attached is used.

If the leading edge of the paper P conveyed by the conveyor belt 16 is curled, the curled portion is guided along the arcuate guide surface 34a of the guide member 34 and the cover 19 The sheet is guided to the guide body 23 through the sheet introduction port portion 19 a and is sent between the heat roller 21 and the press roller 22. When the paper P passes through the heat roller 21 and the press roller 22, the paper is heated and pressed to fix the toner image.

At the time of this fixing, the heat roller 21
The heat is radiated from the through the cover 19 to the gap 32. Although this heat flows as shown by the arrow, it is shielded by the heat insulating material 35 of the partition member 34 and does not diffuse into the apparatus main body 1 in the middle thereof.

Therefore, the cleaning device 8 and the photosensitive drum 2 are not thermally adversely affected. Sheets P1, P2, P3 in FIG. 1 indicate the progress of the sheets with respect to time.

As described above, an arcuate guide surface 34a is formed on the guide member 34 in the portion where the conveyed paper P is in contact, and the paper P is guided so that curl in the opposite direction, that is, downward curl occurs. As a result, unlike the conventional case, the curl portion of the sheet P is not caught by the inner guide body 23 in the sheet introduction port portion 19a, so that a jam or the like does not occur.

Further, even when the paper P passes without passing along the guide surface 34a, it is repelled by the straight line portion 34b immediately after the end of the guide surface 34a, and as a reaction thereof, the leading end of the paper is directed downward and the paper jam occurs. The rate can be reduced.

Further, by attaching a material having a small thermal emissivity such as an aluminum foil on a heat insulating material such as glass wool, and further affixing it to the partition member 33, the effect of blocking the heat flow is further enhanced. Can be large.

[0034]

As described above, the present invention provides claim 1.
According to the fourth aspect, the gap between the cover of the fixing means and the upper housing is partitioned by the partition member, and the medium is guided into the paper introducing port by the guide portion of the partition member. The heat released to the gap can be blocked to prevent the heat from widely flowing into the main body of the apparatus, and the medium is not clogged in the paper inlet.

Therefore, the heat radiated from the fixing means does not adversely affect the other image forming members in the main body of the apparatus, and the medium is securely connected between the heating body and the pressure body. The effect that it can be fixed well by leading to.

According to the second aspect of the present invention, since the partition member is made of a metal material having low heat radiation, it is possible to more reliably block the heat emitted from the fixing means. According to the third aspect, since the partition member is provided with the heat insulating material,
The heat emitted from the fixing means can be blocked more reliably.

According to a fourth aspect of the present invention, an arcuate guide surface is formed on the guide portion of the partition member, and by this guide surface,
Since the leading end of the medium is guided downward and guided to the introduction port of the cover, the medium can be introduced into the introduction port more reliably, and the clogging can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a fixing device that is an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a main body of an image forming apparatus including the fixing device of FIG. 1 is opened.

3 is a diagram showing a part of an internal configuration of the image forming apparatus of FIG.

4 is a perspective view showing a sheet guide member provided in the fixing device of FIG.

FIG. 5 is a configuration diagram showing a part of an internal configuration of a conventional image forming apparatus.

6 is a configuration diagram showing a fixing device provided in the image forming apparatus of FIG.

[Explanation of symbols]

 1A, 1B ... Upper and lower casings 1 ... Device body, P ... Medium K ... Image forming means 15 ... Fixing means 19a ... Introducing part 19 ... Cover 21 ... Heat roller (heating body) 22 ... Press roller (pressurizing body) ) 33 ... Partition member 34 ... Guide part

Claims (4)

[Claims] 1. An apparatus main body comprising upper and lower housings which can be opened and closed, an image forming means for forming a developer image on a medium provided in the apparatus main body, and a heating member provided in the lower housing. And a pressurizing member that is brought into contact with the heating member, and the medium on which the developer image is formed by the image forming means is passed between the heating member and the pressing member to heat and pressurize the medium. And a fixing means for fixing the developer image onto the medium by means of the fixing means, and an introduction port for the medium which covers the outer peripheral portion of the heating body of the fixing means and faces the upper casing with a gap therebetween. A cover, a partition member that projects outward from the inlet of the cover to partition the gap, and a guide portion that is provided on the partition and guides the medium into the inlet along a guide surface. It is characterized by comprising: Image forming device. 2. An apparatus main body composed of upper and lower housings which can be opened and closed, an image forming means for forming a developer image on a medium provided in the apparatus main body, and a heating body provided in the lower housing. And a pressurizing member that is brought into contact with the heating member, and the medium on which the developer image is formed by the image forming means is passed between the heating member and the pressing member to heat and pressurize the medium. And a fixing means for fixing the developer image onto the medium by means of the fixing means, and an introduction port for the medium which covers the outer peripheral portion of the heating body of the fixing means and faces the upper casing with a gap therebetween. A cover, a partition member that projects outwardly at the inlet of the cover to partition the gap, and has a low heat radiation partitioning member, and the partitioning member that is provided on the partitioning member to guide the medium into the inlet along the guide surface. It has a guide part to guide And an image forming apparatus. 3. An apparatus main body comprising upper and lower housings that can be opened and closed, image forming means for forming a developer image on a medium provided in the apparatus main body, and a heating body provided in the lower housing. And a pressurizing member that is brought into contact with the heating member, and the medium on which the developer image is formed by the image forming means is passed between the heating member and the pressing member to heat and pressurize the medium. And a fixing means for fixing the developer image onto the medium by means of the fixing means, and an introduction port for the medium which covers the outer peripheral portion of the heating body of the fixing means and faces the upper casing with a gap therebetween. A cover, a partition member protruding outward from the inlet of the cover to partition the gap, and provided on one surface side of the partition member to guide the medium into the inlet along the guide surface. The guide portion and the other surface side of the partition member An image forming apparatus comprising: a heat insulating material provided on the. 4. An apparatus main body comprising upper and lower housings which can be opened and closed, image forming means for forming a developer image on a medium provided in the apparatus main body, and a heating body provided in the lower housing. And a pressurizing member that is brought into contact with the heating member, and the medium on which the developer image is formed by the image forming means is passed between the heating member and the pressing member to heat and pressurize the medium. And a fixing means for fixing the developer image onto the medium by means of the fixing means, and an introduction port for the medium which covers the outer peripheral portion of the heating body of the fixing means and faces the upper casing with a gap therebetween. A cover, a partition member that projects outward at the inlet of the cover and partitions the gap, and the partition member is provided on the partition member and guides the leading end of the medium downward along an arc-shaped guide surface. And a guide part that leads into the inlet part An image forming apparatus characterized by being provided with a.