CN1160876A - Device for preventing fixing unit from being overheated for use in apparatus using electrophotographic system - Google Patents

Abstract

The invention relates to an overheating protection device, which can shorten the required time of hot-melting part cut-off when fixation mechanism is overheated, the overheating protection device comprises a hot roller arranged above the pressure roller of the fixation mechanism, a heating clamp is arranged inside the hot roller; a bracket for supporting one bearing of the hot roller, one side of the bracket is thin; a hot melting part arranged at one side of the bracket toward the pressure direction that pressure roller is functioned on the hot roller, the hot melting part is also provided with a power cord connection part; and a thermostat arranged at one side of the bracket that contacts with one side of the hot roller, thereby shortening the distance between the hot roller and the hot melting part, so as to shorten the power cut-off time when fixation mechanism is overheated.

Description

In the equipment that adopts electrophotographic system, prevent the device that fixing mechanism is overheated

The present invention relates to a kind of overheated device of hot cylinder that in the equipment (for example laser printer, duplicating machine, facsimile recorder etc.) that adopts electrophotographic system, prevents fixing mechanism.

Referring to Fig. 1, the course of work of the equipment that adopts electrophotographic system once is discussed.

Charger 30 forms uniform charge layer by corona discharge on the outside surface of photosensitive drum 31.Its charged outside surface was subjected to the irradiation of light when photosensitive drum 31 rotated, so form electrostatic latent image on the outside surface of exposure.Electrostatic latent image in photosensitive drum 31 rotating process when the developing mechanism 33 with toner development, thereby on the outside surface of photosensitive drum 31, form appreciable image.Then, paper-feed roll 34 is presented after the recording chart 35, and visual image just is transferred on the recording chart by transfer means 36.

Recording chart 35 tightly sticks on the photosensitive drum 31 by means of electrostatic force, thereby will have separation vessel 37 that recording chart 35 and photosensitive drum are separated.

After so separating, recording chart 35, make the image on the recording chart 35 can be by means of the heat and the pressure photographic fixing of fixing mechanism by between the hot cylinder 38 and pressure roller of fixing mechanism.

On the other hand, clean device 40 and latent image are eliminated lamp bank 41 and are removed photosensitive drum 31 surfaces respectively and go up residual toner and latent images after the transfer printings.

In the equipment of above-mentioned employing electrophotographic system, with image fixing mechanism of photographic fixing on recording chart of transfer printing that type that to be thermostat can contact or separate with hot melt part and hot cylinder.Thermostat is in order to keeping and the suitable temperature of control photographic fixing, and hot melt part then is out of order because of temperature regulator in order to fixing mechanism or the power supply of heating lamp is cut off in maloperation when overheated.

Shown in Figure 2 preventing in the overheated general device of fixing mechanism, overheated prevent mean has a hot cylinder 3 and a hot melt part 7 usually, hot cylinder 3 be located at fixing mechanism pressure roller above, there is heating lamp 2 the inside, hot melt part 7 is located at the side of framework 5 of bearing 4 usefulness of stationary heat cylinder 3, and there is power supply wiring facility 6 its both sides.Hot melt part 7 is connected with the power pack of device and the current circuit of heating lamp 2 in its wiring facility 6, and body plan must make and self do not contact hot cylinder 3 surfaces.

In the general device of Fig. 2, the effect of heating lamp 2 is to produce heat by means of the electric current that device power supply branch provides, and makes the inside surface of this heat radiation to hot cylinder 3.This radiation heat passes to hot cylinder 3 outside surfaces, and outside surface is heated.Overheated or its temperature rises to more than the predetermined temperature if hot cylinder 3 is because of the temperature regulator maloperation, and hot melt part 7 just is cut off, and prepares to be added to the isolated from power of heating lamp 2 and opens so will receive hot melt part 7, thereby prevent that hot cylinder 3 is overheated.

Because general fixing mechanism overheat protection device is placed in the side frame of hot cylinder, and is far away from hot melt part, even thereby framework because of the overheated fusion of hot cylinder, also to just can make hot melt part fusing for a long time.Device is damaged.

Therefore, the purpose of this invention is to provide a kind of overheat protection device that can when fixing mechanism is overheated, shorten the hot melt part fusing time.

For reaching above-mentioned purpose of the present invention, the overheat protection device that the present invention is used for fixing mechanism is such one type: hot melt part is placed in framework affacts the pressure direction of hot cylinder in face of pressure roller a side, so just shortened the distance between hot melt part and the hot cylinder, and the support of stationary heat roller bearings is made with the material that can soften or melt when overheated.

Be understood that above-mentioned and other characteristics of the present invention referring to the detailed description of doing below in conjunction with accompanying drawing.In the accompanying drawing:

Fig. 1 is the synoptic diagram of electronic photographic processor;

Fig. 2 illustrates the structure that prior art prevents the device that fixing mechanism is overheated;

Fig. 3 illustrates the structure that the present invention prevents the device that fixing member is overheated;

Fig. 4 is the cut-open view along the A direction intercepting of Fig. 3;

Fig. 5 is the cut-open view of Fig. 3 B part.

Among all each figure, act on identical parts and all use same numbering to represent.

Referring to Fig. 3 to Fig. 5.The inventive system comprises: hot cylinder 12, be located at above the pressure roller 10 of fixing mechanism, heating lamp 11 is equipped with in the inside; Support 14, bearing 13 usefulness for stationary heat cylinder 12 Yi Bian it is very thin, easily melt when overheated; Hot melt part 16 is arranged on support affacts the pressure direction of hot cylinder 12 in face of pressure roller 10 a side, and there is a wiring facility 15 its both sides; With thermostat 17, be located on the support, contact with the surface of hot-fluid tube 12 1 sides, thereby control the temperature of hot cylinder.The wiring facility 15 of hot melt part 16 is hinged with the power unit put and the current circuit of heating lamp 11 respectively.Hot melt part 16 is located at support affacts the pressure direction of hot cylinder 12 in face of pressure roller 10 a side.The material that support 14 can soften or melt when overheated is made.

Heating lamp 11 produces heat by means of the electric current that the power supply unit branch from device provides, and these heat radiations are to the inside surface of hot cylinder 12.This radiation heat passes to hot cylinder surface, should the surface heating.The temperature of hot cylinder 12 rises when surpassing predeterminated level, and thermostat 17 senses the overheat condition of hot cylinder 12, controls heating-up temperature by making heating lamp 11 stop heating, thereby makes the surface temperature of hot cylinder 12 remain on predeterminated level.Thermostat 17 and temperature regulator maloperation or when ging wrong, hot cylinder 12 keeps the state of being heated, so it is softening to support the support 14 of hot cylinder 12, thus fusing.In the case, hot cylinder 12 promotes support 14 under the effect of pressure roller 10 pressure, convergence hot melt part 16 or contact simultaneously with hot melt part 16, so hot melt part 16 fuses because of the heat that transmits, cut off the power supply of the heating lamp 11 that is connected with hot melt part 16 simultaneously, thereby again hot cylinder 12 is given in not heat supply.So just can prevent because of the overheated device that damages.

In the invention described above, hot melt part is located at support and rolls in heat in face of the pressure roller pressure-acting One side of the pressure direction of tube, thereby the distance between shortening and the hot melt part. Its benefit is: heat When cylinder was overheated, hot melt part fused soon, thereby avoided because of overheated damage device.

Claims (1)

1. one kind prevents the device that fixing mechanism is overheated in the equipment that adopts electrophotographic system, it is characterized in that described device comprises:

A hot cylinder is located on the pressure roller of described fixing mechanism, and heating lamp is equipped with in the inside;

A support, for a bearing usefulness that supports described hot cylinder, the one side of support is thin;

A hot melt part is located at support affacts the direction of the pressure on the hot cylinder in face of described pressure roller a side, and power supply wiring parts are arranged; With

A thermostat is located at the side that described support contacts with the surface of described hot cylinder one side, thereby controls the temperature of described hot cylinder;

Like this, shorten the distance between described hot cylinder and the hot melt part, thereby shortened the time of cutting off the electricity supply of hot cylinder when overheated.

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