JP2505866Y2 - Temperature detector for photoconductor drum - Google Patents

Description

[Detailed description of the device]

[0001]

[Industrial application] The present invention is applied to electrophotographic copying machines and lasers.
Printer such as a photoconductor drum used in
It is used together with a heater on a structure with a curved surface.
The temperature detector used has a particularly excellent thermal response.
Has been devised so that accurate temperature detection can be performed.
Regarding things.

[0002]

2. Description of the Related Art In an electrophotographic copying machine or a laser printer, a photosensitive drum having a photosensitive layer on its surface is used.
The photosensitive drum is rotated while being charged by the main charging unit and then exposed to form an electrostatic latent image on the photosensitive layer, and the electrostatic latent image is transferred to the transfer paper at the transfer unit. Generally, such a photosensitive drum is very susceptible to the influence of the ambient temperature and humidity. For example, when dew condensation occurs on the photosensitive member at a low temperature, the sensitivity of the photosensitive member gradually decreases and a stable electrostatic latent image is generated. The image cannot be maintained, which causes image blurring. Therefore, conventionally, a heater for heating and retaining the temperature of the photosensitive drum and a temperature detector for detecting the surface temperature of the drum are mounted on the photosensitive drum to keep the temperature of the photosensitive drum at an appropriate temperature, thereby stabilizing the temperature. I was trying to get an image.

[0003] Figure 6 is a perspective view showing an example of the photoreceptor drum heater has been conventionally used for the photoreceptor drum of an electrophotographic copying machine, the photoreceptor de with heater 7 6
It is a perspective view showing an example of a temperature detector for photoconductor drums mounted on a ram . As shown in FIG. 6, this heater 101
Has elasticity, a welding sheet on one side, a double-sided adhesive tape,
A cord-shaped heater 104 as a heating element is sandwiched between a metal plate 102 such as stainless steel provided with a heat-welding layer such as an adhesive and a fixing sheet 103 formed of woven cloth, cotton cloth, or the like. , A temperature detector 2 to be described later in the central portion
An opening 105 for fitting 01 (shown in FIG. 7) is provided. The heater 101 is used by being attached to the inside of a photosensitive drum (not shown) while being bent in a substantially cylindrical shape.

As shown in FIG. 7, a temperature detector 201 has a thermistor 203, which is a temperature detecting element, mounted on the central portion of the upper surface of a holder 202 made of a heat-resistant silicone rubber sponge, and the entire surface of the thermistor mounting surface. It has a structure covered with a heat resistant insulating film 204 such as a polyimide film. The temperature detector 201 is configured such that the upper surface of the holder 202 (mounting surface of the thermistor 203) is in contact with the inner peripheral surface of the photosensitive drum via the heat resistant insulating film 204 with a predetermined pressure. It is fitted into the opening 105 of the heater 101 and fixed with a holder etc. while appropriately adjusting the distance.
To be done. The holder 202 made of the heat-resistant silicone rubber sponge has a function of pressing the thermistor 203 toward the photosensitive drum, prevents heat on the drum surface from being transferred to the rear of the thermistor 203, and heat of the heater is transmitted to the thermistor. It has a heat insulating function to prevent transmission to 203. Further, the heat resistant insulating film 204 has a function of fixing the thermistor 203 to the holding body 202.

[0005]

However, the above-mentioned conventional configuration has the following problems. First, in the conventional temperature detector, the temperature detection depends on a slight heat-sensitive portion (element portion) of the thermistor, which is a temperature detection element, and a heat-resistant insulating film is interposed between the thermistor and the drum surface. Therefore, there is a drawback that good heat collection is not performed and the thermal response is poor (response time is slow).
It was

Further, the holder for holding the temperature detecting element is made of low hardness silicone rubber sponge ,
Since it is very soft, it is possible to control the pressure on the photosensitive drum.
Therefore, do not carefully adjust the distance using a complicated holder.
The temperature detector must be attached to the photoconductor drum heater.
I had to do it. If you make a mistake in the distance adjustment,
If the temperature sensor is not pressed apart and the temperature sensor is pressed strongly against the photoconductor drum, the silicone rubber sponge will be subject to permanent compression strain in the shape along the curved surface of the photoconductor drum. There is a drawback in that the detection element is sunk into the sponge and is in the same state as when it is brought into contact with the sponge without applying pressure, so that accurate temperature detection cannot be performed.

The present invention has been made to eliminate the above-mentioned conventional drawbacks, and its purpose is to:
A holder for pressure control and complicated distance adjustment are saved.
Accurate temperature detection without sacrificing excellent thermal response
Knowledge, especially in photoconductors of electrophotographic copiers.
Suitable for use on structures with curved surfaces, such as rams
It is to provide a suitable temperature detector.

[0008]

In order to achieve the above-mentioned object, a temperature detector for a photosensitive drum according to the present invention is molded from silicone rubber having elasticity and heat insulation and has an open top surface.
Holding body having a recessed embedded portion and a protruding portion, and a pair of power sources
Structure from the connected temperature sensing element and the supply leads, and Atsumarinetsutai molded with silicone rubber having a high thermal conductivity
And the heat collector is brought into contact with the inner peripheral surface of the photosensitive drum to generate heat.
Sensing to detect the temperature of the photoconductor drum by combining them
A temperature detector for an optical drum, comprising:
Heat-resistant adhesion by accommodating in the recessed embedded part provided in the holder
Fix it in place by filling it with the agent and then
The heat collecting body is arranged on the surface .

[0009]

[Function] The temperature detection for the photosensitive drum of the present invention having the above structure
Intellectual detector has both the element part of the temperature sensing element and the lead wire part
Through a heat collector molded of silicone rubber with excellent conductivity
To make good thermal connection with the photoconductor drum being measured.
To efficiently collect the temperature (heat) of the photoconductor drum.
Can be. Also, the holder that holds the temperature sensing element is excellent.
It has elasticity and the concave shape provided on the holding body
A temperature-sensitive element is attached at a predetermined position in the embedded part with a heat-resistant adhesive.
The temperature sensor is not positioned because it is securely fixed.
May occur, or if it is strongly pressed onto the photosensitive drum,
Even if they come into contact with each other, the holder may be subject to permanent compression strain.
Disappear. Furthermore, the holder that holds the temperature sensing element is
The central part with the embedded part and the continuous shape
It is composed of a protrusion formed by
Since it functions as a topper, it is a heater for the photosensitive drum.
When mounting on the photosensitive drum,
Installation is extremely easy by simply fitting it into the opening
You can carry out the work. Therefore, it is conventionally required
Complicated pressure control, that is, using a special holder
Surface of the photoconductor drum without adjusting the distance
Capable of accurately detecting temperature with excellent thermal response
Become Noh.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
I will tell. The temperature detector for the photoconductor drum according to this embodiment is shown in FIG.
The structure is as shown in FIGS. First code 2
Has a length of 28 mm, a width of 10 mm, a thickness of 3 mm and a hardness of 50.
This is a holding body made of a silicone rubber molded body having a length of 22 mm, a width of 4 mm, and a depth of 2 mm, and a concave embedded portion 2a having a length of 8 mm, a width of 10 mm, and a thickness.
A pair of protrusions 2b, 2b 'formed to a thickness of 1.5 mm
I have it. Reference numeral 3 is a diode type thermistor as a temperature detecting element housed in the recessed embedded portion 2a ,
The lead wires at both ends of the thermistor 3 have caulked terminals 4,
Power supply lead wires 5 and 5'are respectively connected via 4 ' . The power supply lead wires 5 and 5 ′ are led out to the outside through a hole portion 6 having a length of 2 mm and a width of 4 mm provided on the bottom surface of the recessed embedded portion 2a . Reference numeral 7 is 28 m long
m, width 10 mm, thickness 0.4 mm, thermal conductivity 2 × 10
^A heat collector made of a silicone rubber molded product of ⁻³ cal / cm · sec · ° C., which is arranged in close contact with the peripheral portion of the holder 2 and the upper surface of the thermistor 3 . The heat collector 7 made of this silicone rubber molded product achieves high thermal conductivity characteristics by blending silicone rubber with alumina, silica, zinc oxide, a small amount of boron nitride and the like. Incidentally, reference numeral 8
Is the a silicone-based heat-resistant adhesive filled in the concave embedding portion 2a, the thermistor 3 is concave embedding unit 2 with the vulcanization of the adhesive 8 (30 minutes heat curing at 120 ° C.)
While being held and fixed at a predetermined position in a, the peripheral portion of the holder 2 and the heat collector 7 are firmly bonded and fixed.

Here, the response time of the temperature detector 1 according to this embodiment and the conventional temperature detector 201 shown in FIG. 7 was measured, and it was 63.2% from 25 ° C. to 100 ° C.
The response time was 12.9 seconds in this example, whereas the conventional example was 20.3 seconds, demonstrating the excellent thermal response of the temperature detector according to this example.

Next, the above two types of temperature detectors are brought into contact with the surface of an aluminum tube having a diameter of 100 mm whose temperature is precisely adjusted to 100 ° C. to convert the resistance value of the thermistor when the pressure is increased for a while. The temperature change of the obtained aluminum tube was investigated. As a result, a graph as shown in FIG. 4 was obtained. Graph A
Is according to the present embodiment, graph B is according to the conventional example, and the measured value is a value measured 10 minutes after changing the pressing force.

According to this, in the conventional temperature detector, when the pressure is small, the thermistor does not properly contact the surface of the aluminum tube which is the temperature detection surface, and when the pressure is large, the thermistor is placed in the silicone rubber sponge. It will be understood that accurate temperature detection cannot be performed unless proper pressure (about 200 g) is applied, because it will go under. On the other hand, in the case of the temperature detector according to the present embodiment, since the thermistor that is the temperature detecting element is securely held and fixed by the silicone heat resistant adhesive in the recessed embedded portion provided in the holder,
It can be seen that the thermistor does not go under as in the conventional example, and the temperature detection performance is not impaired by the amount of pressing.

In the present embodiment, the temperature detector having the above construction is further provided.
1 and the conventional temperature detector 201 are shown in FIG.
Incorporated into the ram heater 101 and actually used as a photosensitive drum
I decided to compare them with the temperature detection performance. Real
The temperature detector 1 of the embodiment is a heater for the photoconductor drum, which is manufactured by the following procedure.
Built into the data 101. First, the cord-shaped heater 104 is provided in a predetermined shape on the metal plate 102 provided with the heat-welding layer, and the opening 10 provided in the metal plate 102 is provided.
5 is the central part of the holder 2 (the part where the concave embedding part is provided)
Are fitted with the protrusions 2b and 2b ′ placed on the metal plate 102, and then the fixing sheet 1 is attached to the upper surface of these.
03 was placed by hot pressing . On the other hand, conventional temperature detection
The container 201 is the opening 10 of the heater 101 for the photosensitive drum.
The upper surface of the holder 202 (mounting surface of the thermistor 203)
The side was fitted and fixed with a holder.

In this way, the temperature sensor incorporated in the two
A type of photoconductor drum heater is installed inside the photoconductor drum having an inner diameter of 90 mm, and the surface temperature of the photoconductor drum is set to 4
I tried to control the temperature to get to 5 ° C. The pressure of the temperature detector on the photosensitive drum was adjusted to 200 g. As a result, a graph as shown in FIG. 5 was obtained. Graph C is according to this embodiment , and graph D is according to the conventional example.

According to this, in the conventional temperature detector, the temperature is detected only in a small heat-sensitive portion of the thermistor (thermistor element).
Part) , the response time is slow, the overshoot is large, and the control temperature is high. On the other hand, in the case of the temperature detector according to the present embodiment, the silicone rubber collector having a high thermal conductivity collects good heat, so that the response time is shortened, the overshoot can be reduced, and the control temperature can be further reduced. Is close to the control point.

The present invention is not limited to the above embodiment . For example, in the above-mentioned embodiment , a recessed embedded portion for accommodating the temperature detecting element is formed on the upper surface of the holding body, and a lead wire for power supply is derived from the portion by vertically penetrating part of the embedded portion. It is also possible to form a shape in which the entire recessed embedded portion is vertically penetrated.

[0018]

As described in detail above, the temperature detector of the present invention
Both the element part of the temperature sensing element and the lead wire part conduct heat.
Through a heat collector molded of silicone rubber with excellent properties
To ensure good thermal coupling to the photoconductor drum being measured
Since it is configured, the temperature (heat) of the photoconductor drum can be efficiently maintained.
It can collect heat. Also, hold the temperature sensing element.
The holder has excellent elasticity and
A temperature sensing element is installed at a predetermined position in the recessed embedded part
Since it is firmly fixed with a thermal adhesive, temperature detection
The intelligent element may be misaligned, or if it is pressed hard
Even if it comes into contact with the photoconductor drum, the holder is subject to permanent compression strain.
It disappears. In addition, hold the temperature sensing element
The holding body consists of a central part with concave recesses and both
It is composed of a protrusion formed continuously on the edge,
Since this protrusion functions as a stopper,
When mounting to the body drum heater, the central part is exposed
You only have to fit it into the opening of the body drum heater,
Can be easily installed. Accordingly
The complicated pressure management that was previously required, that is, the special
You can feel the distance without using a separate holder.
Accurately detects the temperature of the optical drum with excellent thermal response
It becomes possible to do.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention and is an exploded perspective view of a temperature detector for a photosensitive drum .

FIG. 2 is a view showing an embodiment of the present invention and is a sectional view of a temperature detector for a photosensitive drum .

FIG. 3 is a diagram showing an embodiment of the present invention for a photosensitive drum.
It is a perspective view of a temperature detector.

[Fig. 4] Pressing of the temperature detector of the embodiment of the present invention and the conventional example
A graph for explaining the relationship between the detected temperature and the change
is there.

FIG. 5: The temperature detectors of the embodiment of the present invention and the conventional example are exposed.
It is a graph which shows the temperature detection performance in the state attached to the body drum .

FIG. 6 is a perspective view of a heater for a photosensitive drum of an electrophotographic copying machine.

FIG. 7 is a view showing a conventional example and is a perspective view of a temperature detector for a photosensitive drum .

[Explanation of symbols]

 1 Temperature detector 2 Holder2a Recessed embedded part 2b protrusion 2b 'protrusion 3 Diode type thermistor (temperature detection element) 4 Crimp terminal 4'clamping terminal 5 Lead wire for power supply 5'power supply lead wire 6 holes 7 Heat collector 8 Silicone heat resistant adhesive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-77731 (JP, A) Actual Kaihei 3-109031 (JP, U) Actual Kaihei 3-130525 (JP, U) Actual Kaihei 1- 137439 (JP, U) Actual flat 3-55540 (JP, U) Actual flat 3-95935 (JP, U) Actual flat 4-3325 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A recessed embedding portion having a top surface opened and a protrusion portion, which is molded from silicone rubber having elasticity and heat insulation.
A holding member was example, is composed of a temperature sensing element connected to a pair of power supply leads, and Atsumarinetsutai molded with silicone rubber having a high thermal conductivity, the photoconductor said heat collecting member
The photoconductor is abutted against the inner peripheral surface of the drum and thermally coupled.
A temperature detector for the photoconductor drum that detects the temperature of the drum.
The temperature detecting element is formed in the concave shape provided in the holding body.
It is housed in the embedded part and placed in place by filling with heat-resistant adhesive.
Fix it and place the heat collector on the top surface.
And a temperature detector for a photosensitive drum .