JPS6032670Y2 - Image forming device temperature detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a temperature detection device suitable for an image forming apparatus applying electrophotography, and specifically relates to a temperature detection device suitable for an image forming apparatus that applies an electrophotographic method.
The present invention relates to a device for detecting the temperature of a cylindrical member such as an illumination lamp.

Conventionally, the temperature of a heated member heated by a heating means such as a nichrome wire heater, an infrared heater, or a halogen lamp has been detected by contacting the surface of the heated member, or by detecting a temperature of about 1 to 2 rrvn from the surface of the heated member. There is a method of arranging temperature detection means at separate locations.

The former method has high detection accuracy, but when damage to the surface of the member to be detected is considered, there are restrictions on the material of the surface of the member to be heated.

On the other hand, in the latter case, since it is non-contact, there is no damage to the detected member, but there is a drawback that the detection accuracy deteriorates because the sensing element is placed at a distance from the detected member. become.

An object of the present invention is to solve the problems of the conventional temperature sensing device described above and to provide an accurate temperature sensing device with a simple configuration.

The present invention, which achieves the above object, includes a cylindrical body heated or warmed by a heat generating means, a cylindrical body that is heated by a heat generating means, a cylindrical body that receives the heat of the cylindrical body in proximity to the circumferential surface of the cylindrical body, and forms a trough. A temperature detection device for an image forming apparatus is characterized in that it has a heat receiving member and a heat detecting means located in a valley of the heat receiving member to detect the temperature of the heat receiving member.

Specific examples of this cylindrical body include embodiments in which the cylindrical body is a rotating fusing roller and the heat receiving member is disposed close to the upper surface of the fusing roller, or an embodiment in which the cylindrical body is a rotating photosensitive drum and the heat receiving member An embodiment in which the member is a shield plate of a corona discharger, a further embodiment in which the cylindrical body is a lamp for illuminating a document, etc., and the heat receiving member is a reflection plate are assumed.

In the present invention, since the heat detecting means measures the temperature of the heat receiving member made of a good heat conductor extending in the axial direction of the cylindrical body, there is no need for this heat detecting means to come into contact with the cylindrical body.

Therefore, the material of the surface of the cylindrical body is not limited in any way, and the mounting position does not have to be limited to the end, making it possible to have a degree of freedom in the configuration.

Furthermore, even though the temperature sensing device of the present invention is non-contact, the temperature of the cylindrical body to be heated or warmed is correctly replaced by the heat receiving member, so that more accurate temperature sensing is possible.

In the present invention, the closer the heat detection means is to the heat-receiving member, the more effective it is, and it is preferable to provide a hole in the heat-receiving member and use this hole to detect both temperatures of the cylindrical body at the same time.

Also, since the temperature of the heat-receiving member will be constant at any position, it may be placed anywhere on the heat-detecting member, but for more accurate detection, the heat-receiving member may be placed anywhere in the surroundings. It is preferable to set

Here, specific examples of heat-detecting members include well-known elements such as sensors that utilize heat conduction or temperature changes in inductance due to the cue point, and heat-receiving members such as brass, copper, aluminum, etc. It is also possible to use metal, ceramic, or other heater pipes that have good thermal conductivity.

In FIG. 1, reference numeral 1 shows a cross section of a heat roller fixing device, which is composed of a heat roller 2 and a backup roller 3 facing thereto.

This heating roller 2 is heated by a heater 4 inside thereof.

Above the heating roller 2, there are 1 to 2 parallel to the roller circumferential surface.
Heat receiving plates 5 are arranged at a distance.

The heat receiving plate 5 has approximately the same length as the axial length of the heating roller 2, and is heated by the heating roller 2 in a short time.

A heat detecting means 6 is fixed to the central portion of the heat receiving plate 5 on the side opposite to the heating roller 2.

According to the conventional detection device, only the heat detection means is placed opposite the heating roller, so it is easily affected by the environment such as air flow around the roller, so accurate detection could not be achieved. However, with the configuration of the present invention, For example, the heat receiving plate 5 can directly receive the heat rising from the heating roller 2 and accumulate it there, and since the heat can be received over a wide area, an averaged temperature can be detected. Highly accurate detection is possible because it does not directly affect the detection element.

Note that when the heat receiving plate is placed beside or below the heating roller, the heat receiving plate is heated by radiant heat from the roller, and it is expected that the heating efficiency will be lower than in the above case.

FIG. 2 shows another comparative example of the device described above.

In this comparative example, an open lower a is formed on the heat receiving plate 7, and the detection means 6
is made to protrude somewhat toward the heating roller 2 side from this opening lower a, or is placed on the same surface as the heat receiving plate 7.

Open lower a is IN from the outer diameter of the detection means 6! An opening approximately 1 inch larger is formed.

In this configuration, the space 8 formed by the heating roller 2 and the heat-receiving plate 7 has a chamber shape, and in particular, the central portion where the open lower door a is located is almost certainly insulated from the outside air.

Therefore, temperature can be detected in a manner similar to a direct measurement method without being affected by environmental conditions.

Examples of the present invention will be described below.

FIG. 3 shows a part of a part where a latent image is formed on a photoreceptor of a copying machine using an electrophotographic method, where 9 is a photosensitive drum having a conductive layer, a photoconductive layer, and a surface insulating layer; It is heated by an internal heater.

Reference numeral 10 indicates a primary discharger for applying a positive charge to the photosensitive drum, and reference numeral 11 indicates a secondary discharger for performing image exposure 12 and providing positive charge by the charger.

13 is a heat receiving plate, a part of which also serves as the shield plate 13a of the primary discharger 10, while the other part also serves as the shield plate 13b of the secondary discharger 11.

The effect of using the heat receiving plate also as a shield plate is that the area of the heat receiving plate can be increased and the functions of the parts can be made multifunctional, thereby making the main body of the device cheaper and more compact.

In the figure, the heat detection means 14 is fixed on a surface 13c of a heat receiving plate parallel to the photosensitive drum.

The heat receiving plate 13 has a length approximately equal to the length of the photosensitive drum 9 in the rotational axis direction.

FIG. 4 shows a hole 13d that is about ITIvn wider than the diameter of the heat detection means 14, which has a circular or rectangular cross section as in FIG. 2 above.
is provided on the heat receiving plate 13 which also serves as a shield plate, and the tip of the heat detecting means is configured to protrude 1 mm from the same plane as the hole or toward the circumferential surface of the photosensitive drum.

In the configurations shown in FIGS. 3 and 4, the heat detection means is located in the trough of the heat receiving plate having a V-shaped cross section, so that it is not affected by the airflow within the apparatus.

As mentioned above, the present invention is characterized by the use of heat-receiving members, and the closer the heat-receiving members are to the circumferential surface of the cylindrical body to be heated or warmed, the wider the facing area, and the thinner the thickness of the heat-receiving members. It becomes possible to accurately read the temperature of the cylindrical body itself to be measured.

Furthermore, the upper part of the cylindrical body is preferable for the arrangement location from the viewpoint of thermal properties.

Of course, the placement location is not limited to the upper part, but may be anywhere near the periphery.

In addition, by configuring the heat receiving member in a shape that extends in the axial direction of the cylinder, it is possible to prevent erroneous measurements caused by temperature unevenness in the circumferential direction of the cylinder, especially if the cylinder rotates, and the entire cylinder It becomes possible to measure.

The heat receiving member of the present invention may be provided along the circumferential direction of the cylindrical body as long as it has a uniform temperature at any position.
In determining the circumferential length and axial width of the heat-receiving member in that case, the circumferential length may be 1/4 to 274 turns, and the axial direction may be approximately equal to the length of the heater, etc.

5 and 6 show perspective views when the heat receiving member is provided in the circumferential direction of the cylindrical body, FIG. 5 shows the case where the cylindrical body is a heating roller of a fixing device, and FIG. indicates the case of a photosensitive drum.

In FIG. 5, 15 is a heating roller, 16 is a backup roller, 17 is a heat receiving plate, and 18 is a heat detection means.

Further, in FIG. 6, reference numeral 19 indicates a photosensitive drum heated by an internal heater, 20 indicates a heat receiving plate, and 21 indicates a heat detection means.

Note that when the heat receiving plate is provided only in the circumferential direction, it is preferable to extend it in the axial direction as much as possible in order to eliminate measurement errors due to temperature differences in the axial direction and to improve response.

[Brief explanation of drawings]

Figures 1 and 2 are comparative examples of the present invention, and are cross-sectional views when applied to a fixing device using a heating roller, and Figures 3 and 4 are cross-sectional views when the present invention is applied to a photosensitive drum. shows. FIG. 5 and FIG. 6 show perspective views when heat receiving plates are provided in the circumferential direction. In the figure, 2 is a heating roller, 5 is a heat receiving plate, 6 is a heat detection means,
9 is a drum-shaped photoreceptor, 13 is a heat receiving plate, 14 is a heat detection means, 15 is a heating roller, 17 and 20 are heat receiving plates, 18.2
1 indicates a heat detection means.

Claims (4)

[Scope of utility model registration request] (1) A cylindrical body that is heated or warmed by a heat generating means, a heat receiving member that is close to the circumferential surface of the cylindrical body and receives the heat of the cylindrical body and forms a valley, and a heat receiving member that is close to the circumferential surface of the cylinder and forms a valley, and 1. A temperature detection device for an image forming apparatus, comprising: a heat detection device positioned to detect the temperature of the heat receiving member. (2) The cylindrical body is a rotating photosensitive drum, the heat receiving member also serves as a shield plate of a corona discharger, and the trough is between two corona dischargers.Claim 1 of the Utility Model Registration Claim A temperature sensing device for the image forming apparatus described above. (3) The image according to claim 1 or 2, wherein the heat receiving member has a shape extending in the axial direction of the cylindrical body, and the heat detecting means is provided in an opening of the heat receiving member. Temperature detection device for forming equipment. (4) The heat receiving member has a shape extending in the axial direction of the cylindrical body, and the heat detecting means is brought into contact with the heat receiving member, as set forth in claim 1 or 2 of the utility model registration claim. Temperature detection device for image forming equipment.