JPS60179768A - Heat insulating device of copying machine with thermal fixing device - Google Patents

Abstract

PURPOSE:To prevent temperature rising due to the radiant heat of a thermal fixing device in a photosensitive body, by providing an adiabatic member between the fixing device and photosensitive body. CONSTITUTION:A heat insulating member 3 is provided between fixing rolles 21 and 22 and a photosensitive body 1 to block the radiant heat from the fixing rollers 21 and 22 so as to protect the photosensitive body 1 from the heat. The heat insulating member 3 blocks the heat at the position shown by the solid line in the figure when the photosensitive body 1 is stopped, but the member 3 moves to the position shown by the dotted line when the photosensitive body 1 is operated so that the member 3 does not interfere with transfer papers being carried at a separating and carrying section. Even though the radiant heat blocking effect of the heat insulating member is slightly lost when the member is moved to the position shown by the dotted line, the majority of the effect is still maintained.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a copying machine having a photoreceptor and a heat fixing device, and particularly relates to a heat insulating device that blocks heat radiated or radiated from the heat fixing device. It is.

(Prior Art) Conventionally, in a copying machine having a heat fixing device, it is known that the heat fixing device is covered with a cover. The first purpose of this fixing cover is to ensure safety. That is,
This is to avoid the risk of the fist directly touching the heat generating part, such as the fixing roller, when removing the jammed paper in the event of a jam.

This cover also had an additional effect of shielding thermal radiation 'f:m from the generating section. However, 1) For the purpose of not interfering with paper conveyance or for the purpose of making it easier to remove jammed paper, the opening needs to have a certain width. Radiant heat is emitted from here.

(2) Since most of the heat generating part is covered, the cover also receives a lot of heat from the heat generating part, and the temperature of the cover also becomes high, causing secondary heat radiation and heat conduction from the cover.

For the above reasons, this cover could not be expected to have a significant heat insulating effect.

However, even with the above-mentioned cover, in the conventional example, there was no problem from the viewpoint of heat radiation to the photoreceptor, but due to the need for miniaturization of the entire device and the copying process. In the case of a structure in which the fixing section and the photoreceptor are close to each other, this thermal radiation becomes a problem.

In addition, a conventional cover with a configuration and structure alone has become insufficient in terms of heat radiation.

In other words, especially in wet-type copying machines, the time required for the process from transfer to fixation tends to affect the image quality of copies, and it is necessary to shorten the distance between the transfer and fixing devices in order to improve image quality. In this case, when the radiant heat from the fixing device hits the surface of the photoreceptor and increases the temperature of the photoreceptor, the photoreceptor has temperature dependence, so it will be affected favorably. Therefore, in such a wet type copying machine, it is necessary to efficiently prevent the temperature rise of the photoreceptor.

(Purpose) The present invention has been developed in view of the background of such conventional examples, and an object of the present invention is to eliminate the drawbacks of the conventional examples described above and prevent the temperature rise of a photoconductor due to radiant heat from heat fixing and fogging. This is the purpose.

(composition) The configuration of the present invention will be explained below based on the illustrated embodiments.

FIG. 1 is a diagram showing the configuration of the main parts of the transfer type electronic copying machine, particularly those related to the present invention.

In FIG. 1, the transfer paper 8 is fed through registration rollers 75 and 76, an image is transferred from the photoreceptor 1 at the position of the transfer corona discharger 6, and the separation claw 5 transfers the image to the fixing roller 21. ．．
It is conveyed to a heat fixing device consisting of 22.

The transfer paper 8 that has passed through the fixing device is further passed through paper ejection rollers 91, 92.
The paper is stored in the paper discharge tray 93 via the paper.

Here, the photoreceptor 1 is driven by the main motor and rotates during the copying operation, but does not perform the copying operation.
During so-called standby, it is stationary.

On the other hand, the temperature of the thermal fuser is not only controlled for the quality of the copied image, but also for the purpose of eliminating or reducing the waiting time until the temperature of the fuser becomes appropriate when copying is started from standby. During standby, the temperature is maintained at a constant temperature by supplying electricity in the same way as during copying, or the temperature is controlled to be maintained within a different temperature range than during copying. In other words, even during standby, the temperature is controlled to be constant.

Therefore, if the structure is such that the radiant heat from the heat fixing section hits the photoconductor surface, only a part of the photoconductor 1 will always receive the radiant heat because the photoconductor 1 is stopped during standby, and the photoconductor 1 pot will Causes body and local temperature rise.

Furthermore, during this waiting period, the cooling fan may also stop or
Furthermore, in the case of a wet-type copying machine, since the supply of the developer and cleaning liquid is also stopped, the cooling effect of the liquid is also reduced, which further increases the temperature of the photoreceptor 1.

In general, many photoreceptors are temperature dependent;
As described above, if there is a temperature rise in whole or in part due to the heat from the fixing device, it will lead to a decrease in copy image quality and is undesirable. However, in the present invention, as shown in the figure, . This heat insulating member 3 is at the position shown by the solid line to block radiant heat when the photoreceptor 1 is stopped, and moves to the position shown by the dotted line when the photoreceptor 1 is rotating.

This is to prevent it from interfering with the conveyance of the transfer paper in the separation conveyance section. However, even at the position indicated by the dotted line, although there is still a slight decrease, the radiant heat shielding effect is not lost. In order to prevent the heat from the heat insulating member 3 from warming the photoreceptor 1, consideration must be given to the material, shape, surface treatment, cooling, mounting structure, etc. of the heat insulating member 3, but any known heat insulating material may be used. Even if this is selected, a sufficient heat insulating effect on the photoreceptor 1 can be expected.

FIG. 2 shows an example of a position variable mechanism for the heat insulating member 3. The structure is such that it rotates around a fulcrum 31. During standby, the solenoid 37 is OFF, so the fixed point 33
The heat insulating member 3 is pulled by a spring 34 fixed to the main body, and is located at the position where it hits the stopper 38 and stops, that is, the position indicated by the solid line in the figure.

During copying, that is, when the main motor is turned on and the photoreceptor 1 is rotated, the solenoid 37 is also turned on, so the armature 36 is turned on.
, one end of the heat insulating member 3 is pulled toward the solenoid 3 via the connecting bar 35t, and rotates about the fulcrum to the position indicated by the dotted line in the figure.

In Figures 1 and 2, the line position 3 of the insulation member and the dotted line position 3'
correspond to each other.

FIG. 3 shows an example of a control circuit for this copying machine.

Portions not shown are the same as those in the known example.

The micro CPU 100K drives the main motor 111 for rotating the photoconductor via the main motor driver 101.
The solenoid driver 102 is controlled by the same signal as the main motor drive, and the heat insulating member solenoid 37 is controlled.

FIG. 4 is a time chart showing the relationship between the main motor 111 (r) ONloFF and the ON10FF of the heat insulating member solenoid 37, and surprisingly, both are synchronized.

FIG. 5 shows a modified embodiment, in which the heat insulating member 3 is adapted to change its position in the direction of arrow B.

FIG. 6 is an example showing a block diagram different from the control block diagram shown in FIG. 3. The solenoid 37 for insulating and heating members does not necessarily need to be synchronized with the main motor 111, and for example, whether transfer paper is being conveyed or not Solenoid 3 for insulation material according to
7 can also be controlled ON10FF.

(Effects) Since the heat insulating member according to the present invention is concerned with the temperature of the fixing section, it has a greater degree of freedom in shape, material, surface treatment, etc. compared to conventional covers that are restricted from easy cooling.

Furthermore, heat radiation from the opening of the cover poses a problem, but since the heat insulating member is placed between the fixing section and the photoreceptor, it can be effectively blocked. Therefore, it is possible to completely close the distance between the transfer section and the fixing section.

[Brief explanation of drawings]

FIG. 1 is a simplified diagram showing the internal configuration of a copying machine according to an embodiment of the present invention, FIG. 2 is a side view showing an embodiment of the operating mechanism of a heat insulating member, FIG. 3 is a control block diagram, and FIG. The figure is a timing chart thereof, FIG. 5 is a simplified diagram of main parts according to a modified embodiment, and FIG. 6 is a block diagram showing another configuration of the control circuit. 1...Photoreceptor, 3...Insulating member, 21
．． 22...Fixing roller that constitutes a heat fixing device. Figure 1 674 Figure 2

Claims (2)

[Claims] (1) A copying machine equipped with a heat fixing device characterized in that, in a transfer type electronic copying machine having a photoconductor and a heat fixing device, a heat insulating member is provided between the photoconductor and the heat fixing device. insulation device. (2) A heat insulating device for a copying machine equipped with a heat fixing device according to claim (1), wherein the position of the heat insulating member is variable.