JPS58154867A - Heat fixing device - Google Patents

Abstract

PURPOSE:To prevent copying paper after fixation from being wetted owing to dew condensation, by providing a fan device which generates an air flow near the copying paper exit of a heat fixing device. CONSTITUTION:The axial flow fan 14 which generates an air flow from below is provided near the copying paper exit between the guide plate 11 and paper discharging roller 13 of the fixing device 7. Without said fan 14, upper high- temperature air Ha and lower low-temperature air La are stirred abruptly when the rear end of copying paper comes out and vapor in the air becomes dew to wet the copying paper, but this fan 14 eliminate air layers having the temperature difference between the parts above and below the copying paper to prevent the condensation, thus preventing the copying paper from getting wet.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat fixing device for copying machines, facsimile machines, and the like.

Conventionally, in a thermal fixing device that performs fixing by heat using a heat roller or the like, there is an air layer inside the fixing device that rises to a high temperature, a low-temperature air layer surrounding the fixing device, and a copy paper that rises rapidly when the copy paper passes through. Due to the temperature difference between the paper and
Condensation often occurs, resulting in wet copies. Figure 1 shows one of the processes in which such a dew condensation phenomenon occurs. (
3) In the state of fixing by K, the air near the copy paper exit of the fixing device (4) is high temperature air H4, Lower II (
The pressure roller (3) side) becomes low-temperature air La. In addition,(
5) is a paper ejection roller. This condition continues in the case where the fixing is finished (but when the copy paper (1) is released, the figure < 4
), at that moment the high temperature air H, and the low temperature air are rapidly stirred, causing the water vapor in the air to condense (
6) and adheres to the copy paper (1), causing water wetting.

Such water-wetting of the copy paper can be a serious defect in terms of copy quality, and may even lead to trouble in the conveyance of the plotter system, and should be avoided as much as possible.

The present invention has been made in consideration of these points, and an object of the present invention is to provide a thermal fixing device that can prevent copy paper from getting wet due to dew condensation after fixing.

By providing a fan device that generates airflow near the copy paper outlet, the present invention eliminates the existence of an air layer with a temperature difference, and is configured to prevent dew condensation caused by rapid surface agitation. This is what I did.

A first embodiment of the present invention will be explained based on FIG.
First, a heat roller (8) and a pressure roller (
9) are provided in pairs, and guide plates a1αchin are provided at the front and rear. Then, heat roller (8) and pressure roller (
9) The copy paper (6) is fixed and conveyed between the
A paper ejection roller α3 is provided on the ejection side.

Therefore, near the copy paper exit, that is, the guide plate αη
- A trickle fan Q4 is provided which is a fan device that generates air tIL from below in the vicinity between the paper discharge rollers (2).

In such a configuration, if we look at the state of the air layer near the copy paper outlet, regardless of the presence or absence of copy paper (b),
The air is constantly stirred by the airflow from below caused by the axial fan α◆, eliminating the existence of air layers with temperature differences. Therefore, as shown in FIG. 1 (4), when the trailing edge of the copy paper (2) has finished coming out, there is no condensation phenomenon due to rapid stirring of the air layer with a temperature difference, and the copy paper (2) does not become wet with water. There are many things that can be prevented. in this case.

The actual amount of airflow needed to generate airflow is relatively small;
As in this embodiment, a small axial fan 04 can be used.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a cage-shaped cross-flow fan (G) is used as a fan device, and is rotated in conjunction with an existing drive motor αQ.

In these embodiments, the airflow is generated from below in the vicinity of the copy paper outlet, but the airflow may be from above, from the side, or from behind.

As described above, the present invention is provided with a fan device that generates air near the copy paper outlet, so that the air layer with temperature difference near the copy paper outlet is eliminated and averaged, and therefore dew condensation occurs. First, it can prevent copy paper from getting wet.

[Brief explanation of the drawing]

Fig. 1(a) (Tsukasa is a side view showing the conventional example, Fig. 2 is a front view showing the first embodiment of the present invention, and Fig. 3 is a side view showing the second embodiment of the present invention. 14... Axial flow fan (fan device), 15... Cross flow fan (fan device)

Claims (1)

[Claims] A heat fixing device equipped with a fan device that generates airflow near the copy paper outlet.