JPH07315657A - Thermal fixing device - Google Patents

Abstract

PURPOSE:To simplify a structure of a thermal fixing device and obtain operation effect at a low cost so as to prevent dew condensation by providing an impeller at an end of a shaft of one paper discharge roller of a pair of paper discharge rollers which are positioned on more downstream than a thermal fixing section. CONSTITUTION:An impeller 16 is fixed at one end in the axial direction of one paper discharge roller 15a of a pair of paper discharge rollers 15 which are provided downstream of a thermal fixing device 13. A paper 11 on which toner image is fixed by a thermal fixing device 13 is discharged onto a paper discharge tray 17 by the pair of paper discharge rollers 15. At this time, the impeller 16 rotates due to the rotation of the pair of paper discharge rollers 15, air current is generated in the axial direction of the pair of paper discharge rollers 15, and air in the downstream of the thermal fixing device 13 is stirred. For this reason, water vapor generated from the paper 11 after it passes the thermal fixing device 13 is blown off by the air current, even if water vapor tends to be condensated on guide plates 14a, 14b, so that dew condensation is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device for heating and fixing a toner image transferred on a sheet in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art In a conventional heat fixing device using a heat roll or the like, a dew condensation phenomenon often occurs near a paper exit. The causes are (1) a temperature difference between the copy paper and the ambient air, which is rapidly raised when the copy paper passes. (2) Due to the temperature rise of the copy paper, the water contained in the copy paper becomes water vapor and exists near the surface of the copy paper,
It occurs by touching the cold paper guide plate. And so on.

As a conventional technique for preventing the occurrence of the dew condensation phenomenon, the one disclosed in Japanese Patent Application Laid-Open No. 58-154867 is provided with a fan device for generating an air flow in the vicinity of the copy paper outlet, and copying is performed. The effect obtained by stirring the air near the exit of the paper, that is, the effect of eliminating the existence of an air layer with a temperature difference and the effect of removing the water vapor near the surface of the copy paper, prevents dew condensation and prevents the paper jam. We try to prevent problems such as copy quality deterioration.

[0004]

However, the above-mentioned conventional technique has a problem that the structure becomes complicated and the cost becomes high because the fan device is provided in addition to the copy paper feeding mechanism.

The present invention has been considered to have cancer as described above. By incorporating an impeller into a ready-made structure, the structure can be simplified, and at the same time, the same effect as the conventional technique can be obtained at a low cost. It is an object of the present invention to provide a heat fixing device that can be used.

[0006]

In order to achieve the above object, a heat fixing device according to the present invention has an impeller at the shaft end of one roll of a pair of discharge rolls located downstream of the heat fixing part. Is provided. The downstream side of the heat fixing unit is composed of a pair of paper discharge rolls and a paper guide plate.

[0007]

[Operation] By rotating the pair of paper discharge rolls along with the thermal fixing operation, the impeller rotates and the air downstream of the thermal fixing section is agitated.

[0008]

EXAMPLES Examples of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic structure of an electrophotographic copying machine. A charger 2 for charging the surface of the photoconductor 1 with a uniform electric potential and an exposure unit for exposing an optical image of a document are shown around the photoconductor 1. 3,
A developing device 4 for developing an electrostatic latent image formed by exposure in the exposure unit 3 into a toner image, a transfer charger 5, a peeling charger 6, a peeling claw 7, a cleaner 8, and a slow-charge exposure device 9. Are sequentially arranged in the rotation direction of the photoconductor 1.

The toner image developed by the developing device 4 on the photoconductor 1 is fed to the paper 1 supplied from the paper feeding device 10.
The image is transferred to the No. 1 by the transfer charger 5. The sheet 11 on which the toner image is transferred is peeled from the photoconductor 1 by the peeling charger 6 and the peeling claw 7, passes through the conveyor belt 12, and then the heat fixing device 1 is formed.
It is sent to No. 3, where it is heat-fixed. Downstream of the heat fixing device 13, a pair of upper and lower guide plates 14a, 1
4b and a paper discharge roll pair 15 are provided.

One roll 15 of the pair of paper discharge rolls 15
The impeller 16 is fixed to one axial end of a. As shown in FIG. 2, the impeller 16 is configured to send air in the axial direction to the paper discharge roll pair 15 side by rotating.

In the above structure, the photoconductor 1 is used in the copying process.
The above-mentioned members are rotated and discharged in synchronization with the above-mentioned members. Then, the toner image is fixed by the thermal fixing device 13, and the paper 11 is ejected to the paper ejection tray 17 by the paper ejection roll pair 15.

At this time, the impeller 17 is rotated by the rotation of the paper discharge roll pair 15 to generate an air flow in the axial direction of the paper discharge roll pair 15, whereby the air on the downstream side of the heat fixing device 13 is above-mentioned. It is agitated by the air flow from the impeller 16.

Therefore, even if the water vapor generated from the paper 11 after passing through the heat fixing device 13 is condensed on the guide plates 14a and 14b, it is blown off by the air flow, so that the condensation is prevented.

In the above embodiment, the paper discharge roll pair 15 is rotated in conjunction with the copy operation. However, the paper discharge roll pair 15 is rotationally driven before the copy operation to perform the copy operation. Prior to this, an airflow is generated by the impeller 16 on the downstream side of the heat fixing device 13, so that the guide plates 15a and 15b are warmed before the sheet 11 passes therethrough to prevent dew condensation at this portion. Good.

[0015]

According to the present invention, since the impeller 16 is simply attached to the discharge roll pair 15 which is a ready-made component, the structure can be simplified and the conventional technique can be manufactured at a low cost. Thermal fixing device 1 having the same effect as
The air on the downstream side of No. 4 can be agitated to prevent dew condensation at this portion.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view of a copying machine using an apparatus of the present invention.

FIG. 2 is a structural explanatory view of a main part of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoconductor, 2 ... Charger, 3 ... Exposure part, 4 ... Developing device,
5 ... Transfer charger, 6 ... Peeling charger, 7 ... Peeling nail, 8
... cleaner, 9 ... exposure exposure device, 10 ... paper feeder, 11
... Paper, 12 ... Conveyor belt, 13 ... Thermal fixing device, 14
a, 14b ... Guide plate, 15 ... Paper discharge roll pair, 15a ... Roll, 16 ... Impeller, 17 ... Paper discharge tray.

Claims (2)

[Claims] 1. A heat fixing device, wherein an impeller is provided at an axial end portion of one roll of a pair of paper discharge rolls located downstream of the heat fixing unit. 2. A thermal fixing device characterized in that a downstream side of the thermal fixing section is composed of a pair of paper discharge rolls and a paper guide plate.