JPS60175068A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent softening of an adhesive resin used for a guide roller, and to eliminate danger of producing unusual odor by forming a means for recovering heat conducted from a heated fixing plate to the guide roller and releasing the heat toward the fixing plate. CONSTITUTION:A heat releasing device 9 installed in a fixing device recovers heat conducted from a heated fixing plate 3 to a guide roller 6 and releases the heat toward the plate 3. The device 9 is provided with 2 legs 11a, 11b, a heat- conducting plate 12, and plural fins 13. The heat conducted from the plate 3 to the guide roller 6 is transmitted through the legs 11a, 11b and the plate 12 to the fins 13, and further given to air sent from a blower 14 and passed through the fins 13, and the heat is again returned to the fixing plate 3 with the heated air, thus permitting softening of a resin and generation of unusual odor, etc., to be prevented even if an adhesive resin is used for the guide roller 6.

Description

Detailed Description of the Invention Technical Field The present invention relates to a fixing plate that is placed along the conveyance path of copy paper carrying an unfixed image and is heated; The present invention relates to a fixing device including a guide roller that guides moving copy paper.

The fixing device described in "Prior Art" 2 is called a so-called hot plate fixing system, and is mainly used in a wet developing system copying machine. Another known fixing method is a fixing method using a heated roller, but this method poses a problem with the so-called offset phenomenon, so the above-mentioned hot plate fixing method has become the mainstream, especially in wet-type copying machines. There is.

Generally, in a hot plate fixing type device, a heater heats a fixing plate placed along the copy paper conveyance path, and while the copy paper is conveyed on the heated fixing plate, images are formed on the copy paper. Heat fix the unfixed image. At this time, a technique is already known in which the adhesion between the fixing plate and the copy paper is increased by using a guide roller disposed at a slight interval between the edges of the fixing plate, thereby achieving efficient fixing.

However, in this device, the heat from the fixing plate is transmitted to the outside through the guide rollers, so the capacity of the heater must be increased accordingly.Moreover, the dissipated heat just wastes time on various parts of the device. It's just heating up and it's wasted. It is extremely uneconomical.

In order to improve image quality or to ensure so-called paper-free properties, which means that good images can be obtained on any type of copying paper, such as thick paper or thin paper, it is often done to increase the amount of toner deposited during development. However, even in this case, in order to ensure good fixing performance, the temperature of the fixing plate must be set to a high temperature, for example, about 210 to 2200, to ensure sufficient drying. When the fixing plate is heated to a high temperature in this manner, the amount of heat transmitted to the guide roller increases accordingly, and the above-mentioned uneconomical effects become significant.

Purpose In view of the above points, it is an object of the present invention to enable effective use of heat from a fixing plate in a hot plate fixing type fixing device.

Configuration The present invention will be described below based on drawings showing embodiments thereof.

FIG. 1 is a side view of an embodiment of a fixing device according to the present invention. In the figure, the copy paper 2 having an unfixed toner image sent by the entrance side conveyance roller 1at1b passes over the fixing plate 3 and is delivered to the paper discharge roller 4a.

4b and discharged by these rollers.

The fixing plate 8 is provided with two heaters 5a and 5b on its lower surface, and is heated in advance by these heaters.

The heating temperature is generally about 210 to 220C as mentioned above. When the copy paper 2 passes over the heated fixing plate 3, the copy paper 2 is dried by the heat from the fixing plate 8, and the toner image is fixed on the copy paper. ' The guide roller 6 disposed opposite the fixing plate 3 pushes the copy paper 2 passing over the fixing plate 3 in the direction of the fixing plate, and as a result, the copy paper 2 and the fixing plate 3 are brought into close contact. This improves the quality of the product and improves its retention. As the guide roller 6, a metal roller whose surface is knurled as shown in FIG. 2 can be used. During the fixing operation, the plotter roller 7 disposed between the guide roller 6 and the conveying roller 1a cleans the guide roller 6. A cleaning roller 8 arranged above the paper discharge roller 4a cleans the paper discharge roller 4a.

By providing the guide roller 6 as described above, the fixing performance to the copy paper 2 is improved. However, due to the presence of the guide roller 6, the heat of the fixing plate 3 is transmitted to the guide roller 6, and furthermore, the heat is wasted from the guide roller 6 toward other members. It is extremely uneconomical. In order to improve this problem, it is effective to make it possible to radiate the heat transmitted to the guide roller 6 toward the fixing plate 3 again, and to reuse the heat for the fixing operation. Any means may be used to radiate heat from the guide roller 6 toward the fixing plate 3, but in this embodiment, a heat radiator shown by reference numeral 9 in the figure is used.

This device includes two leg members 11a and llb that contact the shafts 6a and 6b (FIG. 2) of the guide roller 6 but do not inhibit the rotation of these shafts, and the upper ends of the legs. A heat conductive plate 12 that is connected and extends to the right side of the guide roller 6 (in FIG. 1), a plurality of fins 13 that are attached to the lower surface of the heat conductive plate 12 and hang down toward the fixing plate 3 at appropriate intervals, and a heat conductive plate. A blower 14 is provided above the heat conductive plate 12 and can send air to the upper surface of the heat conductive plate 12. Note that a blower 14 is installed at an appropriate position on the heat conductive plate 12.
A hole (not shown) is provided through which air can pass, and the air that passes through the hole travels downward along the fins 13 and reaches the fixing plate 3. Further, each element except the blower 14 is desirably made of a material with good thermal conductivity.

Since the heat dissipation device 9 having the above-mentioned configuration is attached to the guide roller 6, the heat transmitted from the fixing plate 3 to the guide roller 6 is further transmitted from the foot member 11a
, 1 lb and is transmitted to the heat conductive plate 12.

The heat that has reached the heat conductive plate 12 and diffused within the heat conductive plate rides on the wind from the blower 14 and is sent to the fixing plate 3 through between the fins. Therefore, the copy paper 2 conveyed over the fixing plate 3 receives heat from the fixing plate 3 and the heat from the plurality of fins 13 mentioned above, whereby the fusing operation is performed. Since heat other than the above is also used, reliable fixing can be performed. Furthermore, this heat is originally generated from the fixing plate 3 and was wasted in the past, so it is extremely efficient and economical. The plurality of fins 13 can not only blow air toward the fixing plate 3 but also pick up radiant heat from the guide roller 6.

Generally, in a fixing device that does not use a heat dissipation device as described above,
When the fixing plate 3 is heated to about 210 to 220C, the temperature of the guide roller 6 rises to about 140 to 160C.

However, if heat is reused using the heat radiating device 9 as in this embodiment, the temperature of the guide roller 6 can be lowered to an appropriate temperature as a result. This brings about the following advantages.

As explained in connection with FIG. 2, in this embodiment, a knurled metal roller can be used as the guide roller 6, and in this case, the tip width a(
(Fig. 3) is about ioo to 400μ. The purpose of knurling the surface of the guide roller 6 in this way is to prevent offset of the surface of the guide roller. However, even with such knurling, it is difficult to make the tip width a finer than 100 μm with current processing technology, and therefore, as shown in Figure 3, toner particles 1.
It is possible to avoid the adhesion of 5, but it is not possible to completely prevent offset.

In order to improve this, as shown in FIG. 4, a large number of particles 16 with sharp tips, such as molten aluminum powder, are fixed onto the belt 18 with an adhesive resin layer 17, and the bare L/to 18 is Techniques are known in which the particles 16 are wound around the outer peripheral surface of the guide roller 6 or directly applied to the roller surface. In this way, it is possible to effectively prevent toner from adhering to the tip of the outer circumferential surface of the guide roller 6, that is, from generating offset. As the adhesive resin layer 17, phenolic, epoxy, polyurethane, acrylic, or other resins are generally used.

However, such guide rollers are excellent in both high temperature and fixing properties.

Effects As described above, according to the present invention, the heat transmitted from the fixing plate (3) to the guide roller (6) can be radiated back to the fixing plate, so that the heat transmitted on the fixing plate can be radiated. The copy paper (2) can be subjected to an extremely efficient fixing operation.

[Brief explanation of drawings]

FIG. 1 is a side view of a fixing device that is an embodiment of the present invention, FIG. 2 is a front view taken along line ■-n in FIG. 1, and FIG. 3 is an example of the outer peripheral surface of a guide roller. 4 are diagrams showing other examples of the outer circumferential surface of the guide roller. 2...Copy paper 3...Fixing plate 6...Guide roller 9...Representative of heat dissipation device Patent attorney

Claims (1)

[Claims] The fixing plate is arranged along the conveyance path of copy paper carrying an unfixed image and is heated, and the guide roller is arranged opposite to the fixing plate and guides the copy paper moving on the fixing plate. A fixing device characterized in that the fixing device is provided with means for collecting heat transmitted from a heated fixing plate to a guide roller and radiating the heat toward the fixing plate.