JPH0481779A - image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a copying machine equipped with a fixing device that heats and fuses an unfixed image made of a heat-meltable resin on a recording material via a heat-resistant fixing film. The invention relates to image forming apparatuses such as devices and laser beam printers.

[Prior Art] Image forming apparatuses have conventionally used heat-melting resin (
A fixing device that uses a heat roller is generally used as a means for fixing an unfixed image made of toner.
There are disadvantages such as increased power consumption and a longer time required to reach a temperature that allows fixing.

On the other hand, in order to improve the above drawbacks, for example,
A fixing method using a heat-resistant fixing film has been proposed as described in Japanese Patent Application Laid-Open No. 63-313182.

[Problems to be Solved by the Invention] However, even in a fixing device using the above-mentioned heat roller fixing method or the proposed fixing method, an increase in temperature inside the image forming apparatus due to the fixing device is unavoidable. Due to the trend toward miniaturization and simplification of forming devices, the fixing device has become close to other process units, such as a developing device that visualizes a static TM image using toner, a photoreceptor drum that creates an electrostatic latent image, etc. There has been a problem that the temperature increase caused by the fixing device has an adverse effect on the toner in the developing device and the photosensitive drum, resulting in problems such as improper image density. In addition, in the fixing device itself, if the temperature rises rapidly, it is necessary to use heat-resistant materials for parts such as the pressure roller that presses the recording material against the heating body through the fixing film and the bearing that supports the pressure roller. However, there was a problem in that it led to an increase in the manufacturing cost of the fixing device. Furthermore, with the miniaturization of image forming devices, the cover that forms the exterior surface and the housing that holds the internal parts and units are integrated and made of synthetic resin, eliminating unnecessary space and Many methods have been taken to reduce manufacturing costs by integrating the fuser unit into the housing, and of course the fixing device is also installed in this housing, and the rise in temperature of the fuser unit has a large effect on the housing as well. ABC of materials (acrylic, butadiene, styrene copolymer) and ppo
(Polyphenylene oxide) resin has a heat resistance temperature of 80
The temperature is usually around 100℃, or these materials cannot be used, and expensive heat-resistant materials such as pps (polyphenylene sulfide), PBT (polybutylene terephthalate), unsaturated polyesterel, etc. are used, or the fixing device Since the image forming apparatus was constructed with sufficient space in the housing, there was a problem in that the image forming apparatus became large.

The present invention aims to solve the above problems. That is, an object of the present invention is to provide an image forming apparatus that can suppress temperature rise, can be made smaller and cheaper, and can obtain good images. be.

[Means for Solving the Problems] In order to achieve the above object, the present invention fixes an unfixed image made of a heat-meltable resin on a recording material by heating it through a heat-resistant fixing film. The image forming apparatus includes a fixing device, and an opening communicating with the outside of the image forming device is provided below the fixing device.

[Function] According to the present invention, since the fixing device is provided with an opening communicating with the outside of the image forming device below, temperature rise inside the device can be suppressed, and the device can be made smaller and cheaper. This makes it possible to obtain good images.

[Embodiment] FIGS. 1 and 2 show a first embodiment of the present invention, in which FIG. 1 is a side sectional view of the image forming apparatus near the fixing device, and FIG. It is a top view seen from arrow line AA of a figure.

In FIG. 1, 1 is a heating element, and 2 is a fixing film. The fixing film 2 is made of a heat-resistant resin such as polyimide or polyetherimide and has a thickness of about 20 μm, and one side of the film is coated with a release layer such as PTFE (tetrafluoroethylene resin). The total thickness of the fixing film 2 is generally preferably 50 μm or less. Reference numeral 3 denotes a driving roller, and a coating layer of silicone rubber or the like is provided on the surface of a core metal such as iron. A driven roller 8 is made of steel or the like. The fixing film 2 has a drive roller 3 and a driven roller 8.
A hook is passed between them and holds the heating element 1. In addition, together with the holder 6 made of heat-resistant resin, a film transport path is formed. The fixing film 2 is under tension by a biasing means (not shown) so as not to sag. Further, the drive roller 3 is rotated in the direction of arrow B by a drive means (not shown), and the pressure roller 5 whose surface is covered with heat-resistant rubber such as silicone rubber is also rotated in response. The recording material P to be fixed is fed from a paper feeding means (not shown), and the toner image developed by the developing device 12 is transferred onto the photoreceptor drum 10 by the transfer section 13, and the toner image is transferred to the fixing population guide 4.
The toner image transferred onto the recording material P is guided to the fixing section 17 and is fixed as a permanently fixed image.
, and is discharged to the outside of the machine by a pair of paper discharge rollers 16.

On the other hand, the toner remaining on the surface of the photoreceptor drum 10 after the transfer is scraped off by the cleaning unit 11 and collected.

The fixing device is fixed to a general-purpose synthetic resin housing 9 whose outer surface is the exterior surface, and the distance between the fixing section 17 and the transfer section 13 is set to be less than the size of the smallest recording material such as a business card. ,
The configuration does not require any special recording material conveying means between the transfer section 13 and the fixing section 17. This is effective in reducing the size of the device and the cost of the device. However, the fixing unit 17, which is a heat source, and the photosensitive drum 1, which is necessary for image formation,
The cleaning unit 11 that stores zero and toner and the developing device 12 that visualizes the electrostatic latent image are located close to each other.

The housing 9 has an opening 9b near the fixing device, and an exhaust fan 14 above the fixing device. Therefore, as shown by the arrow C, when the outside air passes through the opening 9b, it cools the casing 9, passes near the pressure roller 5 and the fixing film 2, and is cooled, thereby causing the fixing device and the cleaning unit 11 to be cooled. It passes through the space and is discharged to the outside by the exhaust fan 14,
Cooling of the fixing device and heat influence on the cleaning unit 11 are prevented. At this point, perhaps a part of the fuser is cooled, or in the case of the wood-type fuser, the heating element 1 is connected to the fixing film 2.
Since the method directly heats and fixes the toner on the recording material P via the fixing system, problems with fixing performance such as insufficient fixing do not occur.

The opening 9b of the housing shown in FIG. 2 has a larger aperture ratio at the ends than at the center. This is done in consideration of cooling since the recording material is passed with the center as the reference, so when a small recording material is passed, the temperature will rise at both ends.

FIG. 3 corresponds to FIG. 2 and shows a second embodiment of the invention, and FIG. 4 similarly shows a third embodiment of the invention.

In the second embodiment, the openings 9b at both ends are made larger than the opening 9b at the center, and in the second embodiment, the recording material is passed from one side to the other. Since the upper end is used as a reference, the aperture ratio of the opening 9b at the lower end is increased.

[Effects of the Invention] As described above, according to the present invention, an opening communicating with the outside of the image forming apparatus is provided below the fixing device that heats and fixes toner on a recording material via a heat-resistant fixing film. This makes it possible to properly cool the inside of the device with outside air, eliminating thermal effects on the photoreceptor drum and toner, producing good images with appropriate density, and making it possible to downsize the device. Become. Further, the temperature rise of the fixing device itself is suppressed, and the material of the bearing portion and the like can be made of a material with relatively low heat resistance, making it possible to reduce the cost of the device. Furthermore, the temperature rise in the vicinity of the fixing device of the housing is suppressed, it becomes possible to use a general-purpose synthetic resin material, and a low-cost device can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view showing the first embodiment of the present invention;
The figure is a plan view as seen from the arrow line A-A in FIG. 1, FIG. 3 is a plan view showing the second embodiment of the present invention, and FIG.
FIG. 2 is a plan view showing an example. 1... Heating body 2... Fixing film 3.
... Drive roller 5 ... Pressure roller 8 ... Followed roller 9 ... Housing 9b ... Opening
10... Photosensitive tram 11... Cleaning unit 12... Developing device 13... Transfer section 14...
・・Exhaust fan 17・Fixing section and 4 other people

Claims (1)

[Scope of Claims] 1. In an image forming apparatus equipped with a fixing device that heats and melts an unfixed image made of a heat-meltable resin on a recording material through a heat-resistant fixing film, An image forming apparatus characterized by comprising an opening at the bottom that communicates with the outside of the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the aperture ratio of the aperture is larger at at least one end in a direction perpendicular to the recording material passing direction than at the center. 3. The image forming apparatus according to claim 1 or 2, further comprising an exhaust fan above the fixing device. 4. The image forming apparatus according to claim 1, 2 or 3, wherein an opening is provided in the synthetic resin member, a part of which is an exterior surface.