JPS5821776A - Fixing device for toner image - Google Patents

Abstract

PURPOSE:To improve the utilization efficiency of heat and to make a device small in size and simple by sandwiching and feeding recording paper under pressure with a heating roller in contact with the surface of the recording paper stuck with toner images and a hot plate in contact with the opposite surface of the recording paper. CONSTITUTION:A heating roller 1 is in the position apart from a hot plate 2 and a surface plate 3 as shown by solid lines until recording paper P is fed to a fixing device. When the paper P stuck with toner images T is conveyed and the leading end thereof arrives at a means 6 for detecting the entrance of the recording paper, the roller 1 descends to sandwitch and feed the paper P under pressure between the plate 2 and the plate 3 at the point of the time when the leading end of the paper P arrives below the roller 1 in accordance with the signal for the entrance of the recording paper. The heat roller ascends at the point of the time when the trailing end of the paper P passes therethrough. Since the paper P is preheated upon arrival at the plate 2 and the plate 3, it is possible to lower the temp. of the roller 1 and the plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a toner image fixing device such as an electrophotographic copying machine.

As a conventional toner image fixing device, there is a 4DI opposing hot plate.
IKIF! A non-contact method in which paper is passed through, a non-contact method in which one and both of the above heating plates are replaced with infrared lamps, etc., a contact heating method in which the recording paper is held between a pair of heating plates and fed, and a pair of rigid rollers. A pressure fixing method is known in which the recording paper is fed by applying strong pressure. ζHere, the non-contact method refers to the fact that a heating source such as a hot plate does not come into contact with the toner-attached side of the recording paper, and the opposite side where the toner image to be fixed is not attached. This includes contact of the heating source with. Comparing the non-contact method and the contact heating method, we find that the non-contact method has the advantage that there is no need to worry about Off-Cera F of the toner image during fixing, but the energy usage efficiency is low. There are some problems, such as keeping the hot plate at a high temperature (9) and elongating the heating section. On the other hand, with the contact heating method, there is a risk of offset to the heating roller during fusing, but it generally has a high energy usage efficiency, and therefore has the advantage that the temperature of the heating roller does not need to be that high. be. However, this advantage cannot be fully exploited in the method of feeding the recording paper by holding it between a pair of heating rollers because heating is performed only at the contact line of the rollers. Certain offset problems can be solved without actually causing any trouble by providing an offset prevention layer such as tetrafluoroethylene rubber or silicon rubber on the heating roller.

In contrast to the above heating method, the pressure fixing method uses J7
-30#/C111 strong linear pressure (with a contact heating method, a clamping pressure of at most several kll/clI at 11t) VClk causes the fixed toner image to have a glaring luster and toner to become less soft. It has some drawbacks, such as requiring a certain amount of equipment.

The present invention relates to the improvement of the contact heating method, and the present invention is capable of making the most of the advantages of the contact heating method, and is small and simple.
The present invention provides a toner image fixing device that obtains 1I*L.

This is the real deal! The IO toner image fixing device is characterized in that the recording paper is pinched and fed between a heating roller that contacts the toner image-attached surface of the recording paper and a hot plate that contacts the opposite surface of the recording paper.

Hereinafter, the explanation will be given based on the illustrated example of the tube of the present invention.

1 and 1 are respectively schematic side views showing lf4 of the device of the present invention.

In 11, l is a heating roller, ko is a hot plate, and 3 is a hot plate 2.
0 is a surface plate provided to improve the slippage of the recording paper P on the surface, 3 is a separation claw to prevent the recording paper from wrapping, j is a reflective cover to improve thermal efficiency, and 1 company recording paper entry detection means . What is more, /a and /bd are each provided with a lamp heater and a resistance wire that heat the heating roller I, and the above-mentioned offset prevention layer is provided on the surface of the heating roller I. t and a are weights for restoring the detection means B.

Next, the operation of these devices will be explained.

The heating roller l and the hot plate are heated by turning on the main switch of the copying machine or turning on the copying start switch. Until the recording paper P is sent to the fixing device, the heating roller l is at a position away from one heating plate and the front plate 3, as shown by the solid line in FIG. Then, the recording paper P to which the toner image is attached by a known means of transfer force is conveyed by a feeding conveyance means (not shown) with the surface to which the toner image is attached as a heating roller, and the leading edge enters the recording paper. When the detecting means B is reached, the detecting means t operates, for example, a microswitch to generate a recording paper entry signal. Based on the signal, the heating roller 1 is lowered when the leading edge of the recording paper P reaches below the heating roller 1, and from then on, the heating roller 1 is moved down until the trailing edge of the recording paper P passes through the heating plate. The recording paper P is conveyed while being pinched between the front plate J and the front plate J. Then, at the time when the trailing edge of the recording paper PO passes, the heating roller I rises to its original remote position.

Before that, the leading edge of the recording paper P appears to be conveyed by a sand conveying means (not shown), so that the recording paper P passes through the fixing device without delay.

According to the fixing device of the present invention, the recording paper P is heated in advance from the time it reaches the heating plate 3 or the front plate 3, so that the heat utilization efficiency is significantly increased compared to the conventional contact heating method. As a result, the temperature of the heating roller l and hot plate can be lowered, and the size of the apparatus can also be simplified.

In addition, in the present invention, if a smooth surface is used for the heating plate, it is of course not necessary to separately provide the surface plate J, and the heat capacity of the heating roller I and the heating plate is By making the size as small as possible, the copying machine can be made ready for copying immediately after the main switch is turned on. Also, the recording paper entry detection means 4 in FIG. 1 indicates that the recording paper is in progress! 1
! Using a gear plate that rotates in contrast, the gear plate is combined with a rechargeable pulse signal generator, and the leading edge of the recording paper P is caused to touch the heating roller L by the pulse signal generated as the gear plate rotates. Find the point at which the heating roller reaches the bottom.
When the recording paper P is wrapped around the surface, the trailing edge of the recording paper P moves faster due to the layered windings, so it is detected that the pulse signal generation period becomes shorter. It is also possible to issue a winding warning or stop the copying machine.

Furthermore, a recording paper PO detection means is provided on the receiving and conveying means side, and occurrence of a jam between the two detection means is detected based on the recording paper entry detection means and the detection signal of the detection means, and a warning and a stop are issued. Of course it is possible.

[Brief explanation of drawings]

FIGS. 1 and 2 each show an apparatus according to the present invention. FIG. 2 is a schematic side view showing one example. l...heating roller, c-heating plate, 3...surface plate, cf. separation claw,! ...reflective cover,
6-・Note-Paper entry detection means. Patent applicant: Konishiroku Photo Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A toner image fixing device characterized in that a heating roller that contacts the donor image-attached surface of the recording paper and a heating plate that contacts the opposite side of the recording paper press and feed the recording paper.