JPH09281830A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool a paper sheet after passing through a heating place by providing a paper cooling roller coming into contact with the paper after passing through the heating place and having a large number of holes for blowing cooling air on the paper. SOLUTION: The paper cooling roller 1 can be rotated according to the paper 4 and further, arranged just after a heating roller 5 and a pressure roller 6. Air outside an electrophotographic printer for consecutive sheets is blown into the paper cooling roller 1 through a hose 3 by the sucking or blowing of a blower 2, etc. The fed outside air blows off from a large number of holes 1a made in the cooling roller 1. Since the cooling roller 1 is made of a material excellent in heat conductivity, when the roller is deprived of heat inside, the outer peripheral temp. of the cooling roller 1 is lowered as well. Thus, the paper 4 can be cooled without flapping and degrading foldability. Further, the paper 4 is cooled just after fixing, so that the cooling efficiency of the paper can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device that conveys a sheet bearing a toner image to a heating field and fixes the toner image on the sheet.

[0002]

2. Description of the Related Art As a fixing device for an electrophotographic apparatus, there is a method of fixing a toner image on a sheet while holding the sheet holding the toner image between a heating roll and a pressure roll which are in pressure contact with each other. There is something.

By the way, in a fixing device of this type which uses at least a thermal action when fixing a toner image on a sheet, if the sheet that has not cooled down is sent to a discharge section after the fixing step, the toner on the sheet will be removed. If it cools and solidifies while it is in contact with other paper, or if you use continuous paper as the paper and fix the toner image on the continuous paper, then eject it while folding the continuous paper, or perform double-sided printing. In some cases, the so-called “toner stick phenomenon” occurs in which the toner on the sheet is combined with the toner formed on another sheet, and the combined state cools and solidifies.

Therefore, conventionally, in order to cool the hot paper after fixing, air is blown to the paper by a blower or the like inside the stacker to cool it.

[0005]

However, in the prior art, when the air volume of the cooling air is increased, the paper flutters and the foldability is deteriorated. Therefore, the flow rate of the blown air cannot be increased so much and the cooling capacity is limited. was there.

Since the ambient temperature inside the stacker device installed behind the fixing device is higher than the normal temperature, it is difficult to obtain the effect of cooling the paper even if air is blown to the paper. Further, even if outside air is blown onto the paper, the air stagnates inside the stacker, and it is difficult to obtain the effect of cooling the paper.

An object of the present invention is to provide a fixing device which can efficiently cool a sheet that has passed through a heating field.

[0008]

SUMMARY OF THE INVENTION The above-mentioned object is to fix a toner image on a sheet by conveying the sheet holding the toner image to the heating field and fixing the toner image on the sheet. This is achieved by providing a paper cooling roll having a large number of holes for blowing cooling air.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

The sheet cooling roller 1 can rotate following the sheet 4, and also has a heating roller 5 and a pressure roller 6.
Is placed immediately after The air outside the continuous paper electrophotographic printing apparatus is passed through the hose 3 inside the paper cooling roller 1 by suction or discharge of the blower 2 or the like.

The external air sent in is cooled by the cooling roller 1.
Is blown out from a large number of holes 1a formed in the. Further, since the sheet cooling roller 1 is formed of a material having good thermal conductivity,
When heat is taken inside the roller, the outer peripheral temperature of the sheet cooling roller 1 also decreases.

With the above configuration, the sheet 4 does not flap,
It is possible to realize sheet cooling without deteriorating the foldability. Further, since the paper 4 is cooled immediately after fixing, the paper cooling efficiency is improved. Further, a cooling device 7 is mounted between the blower 2 and the paper cooling roller 1,
By cooling the cooling fluid 8, the cooling capacity is improved.

[0013]

According to the present invention, it is possible to provide a fixing device capable of efficiently cooling a sheet that has passed through a heating field.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a fixing device of the present invention.

FIG. 2 is a sectional side view of a main part of the fixing device according to the present invention.

[Explanation of symbols]

1 ... Paper cooling roller, 1a ... Hole, 2 blower, 3 ... Hose, 4 ... Paper, 5 ... Heating roller, 6 ... Pressure roller, 7 ...
Cooling device, 8 ... Cooling fluid.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuuo Nakajima 1060 Takeda, Hitachinaka City, Hitachi, Ibaraki Hitachi Koki Co., Ltd. (72) Hiroshi Shirada 1060 Takeda, Hitachinaka, Ibaraki Hitachi Koki Co., Ltd.

Claims (1)

[Claims] 1. A fixing device for transporting a sheet carrying a toner image to a heating field and fixing the toner image on the sheet,
A fixing device, characterized in that a sheet cooling roll is provided, which is provided with a large number of holes that come into contact with the sheet that has passed through the heating field and blow cooling air onto the sheet.