JP2006300701A - Temperature detector, and fixing device with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dust and refuse such as toner and paper powder from being deposited onto a temperature detecting part by flying thereof, and to properly detect a temperature, in a noncontact type temperature detector for detecting a surface temperature of a member. <P>SOLUTION: The temperature detector 10 is provided in an upper side of a thermal roller 2 for a fixing member of a fixing device 1. The temperature detector 10 is provided with a temperature sensor 11, a blowing means 12, and a guide member 13. The temperature sensor 11 is provided with a temperature detecting part 11a for detecting an infrared ray on a bottom face, and is arranged to have a prescribed clearance in the upper side of the thermal roller 2. The blowing means 12 is arranged in an upper part of the temperature sensor 11, and the guide roller 13 is extended from a portion on a bottom face of the blowing means 12 up to the vicinity of a surface of the thermal roller 2, in a form of covering the temperature sensor 11 entirely in its inside. The dust and the refuse such as the toner and the paper powder are thereby prevented from flying into the portion of the temperature detecting part 11a by an air flow from the blowing means 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a temperature detection device that detects the surface temperature of a member, and more particularly to a non-contact temperature detection device. The present invention also relates to a fixing device equipped with this temperature detection device for temperature control of the fixing member and / or the pressure member.

  In an electrophotographic image forming apparatus typified by a copying machine or a printer, a thermal fixing method is widely used as a method for fixing an unfixed toner image transferred onto a sheet by a transfer unit. In this heat fixing method, two rotating members composed of rollers and belts are pressed against each other to form a nip, and a heating means is arranged near one or both of these rotating members to rotate. By heating the member and inserting a paper carrying an unfixed toner image in the nip, the toner is fixed on the paper.

  As a heat fixing type fixing device, a roller that directly contacts an unfixed toner image on a sheet of two rollers constituting a pair of rollers that are in pressure contact with each other is a heat roller (fixing member). A built-in heating means such as a halogen lamp is generally used. In order to obtain a stable fixing property, the surface temperature of the heat roller is monitored by a temperature detection device equipped with a temperature sensor such as a thermistor, and the amount of heat generated by a heating means such as a halogen lamp is controlled to control the surface temperature of the heat roller. Is maintained at an appropriate temperature.

Conventionally, the surface temperature of the heat roller has been detected by a contact-type temperature detecting device that contacts the surface. That is, a temperature sensor such as a thermistor is brought into contact with the non-sheet passing area of the surface of the heat roller, and the temperature control of the heat roller by the heating means is performed based on the surface temperature of the non-sheet passing area. However, when the temperature sensor is brought into contact with the surface of the heat roller, the surface of the heat roller is damaged, or toner or paper dust remaining around the temperature detection device adheres to the temperature detection part of the sensor, so that an appropriate temperature detection is possible. There was a problem that could not be done. Therefore, in order to solve such a problem, a temperature detection device provided with a non-contact type temperature sensor that is provided at a position slightly away from the surface of the heat roller and detects the surface temperature is proposed. 1 can be seen.
JP-A-6-194994 (page 3-5, Fig. 1-3)

  Here, in the vicinity of the surface of the heat roller, it is known that a slight air flow is generated in the circumferential direction by the rotation of the heat roller. Then, the toner and paper powder remaining around the temperature detection device may be scattered by the air flow and reach the temperature detection unit of the temperature detection device. There is a concern that dust or dirt such as toner or paper dust may adhere to the temperature detection unit, which may be an obstacle to obtaining thermal energy from the surface of the heat roller and may adversely affect the temperature detection of the surface of the heat roller. .

  In the fixing device described in Patent Document 1, a thermistor cover is provided in the temperature detection device, and a roller that contacts the surface of the heat roller is attached to the thermistor cover to maintain a predetermined gap with the surface of the heat roller. However, it cannot be denied that toner or paper dust may enter the thermistor (temperature sensor) inside the cover from the gap between the thermistor cover and the surface of the heat roller. Furthermore, there is a possibility that toner or paper dust adheres to the roller and accumulates, so that the gap between the thermistor cover and the surface of the heat roller is widened, and the toner and paper dust can easily enter the thermistor cover. It is done. Accordingly, there is a need for a temperature detection device that actively prevents toner and paper powder remaining around the temperature detection device from being scattered and attached to a temperature detection portion such as the thermistor.

  The present invention has been made in view of the above points, and in contrast to a non-contact type temperature detection device that detects the surface temperature of a member, dust such as toner and paper dust remaining around the temperature detection device in the fixing device. Another object of the present invention is to provide a temperature detection device capable of preventing the dust and dust from scattering and adhering to the temperature detection unit and performing appropriate temperature detection. It is another object of the present invention to provide a fixing device equipped with such a temperature detection device.

  In order to solve the above-described problems, the present invention provides a non-contact type temperature detection device that detects a surface temperature of a member, a blowing unit, and a guide member that guides an air flow obtained by the blowing unit to a temperature detection unit. It was decided to prepare.

  In the present invention, the temperature detection device is mounted on the fixing device in order to detect the surface temperature of the fixing member and / or the pressure member.

  In the fixing device having the above-described configuration, the temperature detection device is disposed above the fixing member and / or the pressure member.

  In the fixing device having the above-described configuration, the air flow is directed downstream in the rotation direction of the fixing member or the pressure member as the guide member of the temperature detection device approaches the fixing member or the pressure member. It was decided to make the shape which becomes.

  Further, in the fixing device having the above-described configuration, the air blowing unit of the temperature detection device is driven when the fixing member or the pressure member rotates.

  According to the structure of this invention, in the non-contact-type temperature detection apparatus which detects the surface temperature of a member, it is provided with a ventilation means and a guide member which guides the airflow obtained by this ventilation means to a temperature detection part. Therefore, it is possible to prevent dust and debris from being scattered at the location of the temperature detection unit due to the air flow from the blowing means. Thereby, the thermal energy of the member surface required in order to detect the surface temperature of a member reaches | attains a temperature detection part, without receiving to the influence of dust and dirt. Therefore, it is possible to obtain a temperature detection device that can perform more appropriate temperature detection.

  In the present invention, since the temperature detection device is mounted on the fixing device in order to detect the surface temperature of the fixing member and / or the pressure member, dust and dust such as toner and paper dust are scattered. Therefore, it is possible to obtain a high-performance fixing device including a temperature detection device that can prevent the adhesion to the temperature detection unit and can perform appropriate temperature detection.

  Further, in the fixing device having the above-described configuration, the temperature detection device is disposed above the fixing member and / or the pressure member. Therefore, the toner and paper dust remaining around the temperature detection device are removed from the air from the blowing unit. In addition to the flow, their own weight acts, and it becomes difficult to reach the temperature detection unit. As a result, the accuracy of temperature detection by the temperature detection device can be improved, so that more accurate temperature control can be performed in the fixing device.

  In the fixing device configured as described above, the guide member of the temperature detection device has a shape in which the air flow is directed downstream in the rotation direction of the fixing member or the pressure member as it approaches the fixing member or the pressure member. As a result, the air flow can be sent out from the blowing means without countering the slight air flow in the circumferential direction in the vicinity of the surface caused by the rotation of these members. As a result, the toner and paper dust remaining around the temperature detection device are moved away from the temperature detection device without being disturbed and approaching the temperature detection unit.

  Further, in the fixing device having the above configuration, the air blowing means of the temperature detection device is driven when the fixing member or the pressure member rotates, so that toner and paper dust are scattered by the air flow generated by the rotation of these members. It can suppress becoming easy. In this way, by driving the air blowing means only when the toner or paper dust is likely to be scattered, the temperature detection accuracy can be increased, and in addition, the power consumption of the fixing device can be reduced. Become.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  First, a detailed configuration of the fixing device equipped with the temperature detection device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of a fixing device equipped with a temperature detection device. In the figure, solid arrows indicate the rotation direction of the heat roller and pressure roller, and white arrows indicate the direction of air movement.

  As shown in FIG. 1, the fixing device 1 includes a heat roller 2 as a fixing member and a pressure roller 3 as a pressure member. The heat roller 2 and the pressure roller 3 are pressed against each other with a predetermined pressure to form a fixing nip having a predetermined width in the sheet conveyance direction. A sheet carrying an unfixed toner image passes through the fixing nip. The heat roller 2 is in direct contact with the unfixed toner image on the paper.

  The heat roller 2 is driven to rotate by driving means (not shown). The pressure roller 3 rotates according to the rotation of the heat roller 2 by being in contact with the heat roller 2. In a normal fixing operation, the heat roller 2 rotates in the clockwise direction and the pressure roller 3 rotates in the counterclockwise direction so as to fix the unfixed toner on the surface of the sheet while conveying the sheet from below to above in FIG. .

  The heat roller 2 has a diameter of 40 mm and includes an elastic member layer on the surface of a core material such as an aluminum tube. The elastic member layer is made of silicon rubber and has a thickness of 2 mm. A release layer is provided in close contact with the surface of the elastic member layer to improve smoothness and toner release properties. For the release layer, a fluorine-based resin such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is used, and the layer is provided by applying a paint or covering the tube. A PFA tube has a thickness of 60 μm, and a fluororesin paint has a thickness of 25 μm.

  The pressure roller 3 is provided with sponge silicon rubber constituting an elastic member layer on the outside of a cored bar made of stainless steel.

  Inside the heat roller 2, as shown in FIG. 1, a halogen lamp 4 as a heating means is disposed. The halogen lamp 4 as a heating means heats the heat roller 2 from the inside. The halogen lamp 4 has a rod shape extending in the axial direction of the heat roller 2, and two halogen lamps 4 are provided. The heat generated from the halogen lamp 4 is transmitted through the core material and the elastic member layer of the heat roller 2 to reach the surface, and the heat of the surface of the heat roller 2 melts the unfixed toner carried on the paper.

  As shown in FIG. 1, a temperature detection device 10 is provided above the heat roller 2. The temperature detection device 10 is a non-contact type temperature detection device that detects the surface temperature of the heat roller 2, and is disposed at a substantially central portion in the axial direction of the heat roller 2. The temperature detection device 10 includes a temperature sensor 11, a blower 12, and a guide member 13.

  The temperature sensor 11 is disposed above the heat roller 2 with a predetermined gap. The temperature sensor 11 is composed of a thermistor or the like, and detects the temperature by obtaining infrared rays or the like emitted from the surface of the heat roller 2 as heat energy. The temperature detection unit 11 a that actually detects the temperature is provided on the bottom surface of the temperature sensor 11.

  The air blowing means 12 is disposed further above the temperature sensor 11. And the ventilation means 12 is comprised with the fan, and is attached so that the airflow which goes to the temperature sensor 11 provided in the downward direction may generate | occur | produce. The blowing means 12 is driven when the heat roller 2 rotates, that is, when a fixing operation is being performed.

  The guide member 13 is disposed below the blower unit 12. The guide member 13 has a cylindrical shape whose upper end is in close contact with the bottom surface of the air blowing means 12 and whose lower end extends to the vicinity of the surface of the heat roller 2. And the temperature sensor 11 is arrange | positioned in the form covered completely inside the guide member 13. FIG. As a result, the air flow obtained by the air blowing means 12 is guided to the position below the temperature sensor 11, that is, to the location of the temperature detection unit 11 a provided on the bottom surface of the temperature sensor 11. Note that the lower end of the upstream side wall portion 13a corresponding to the upstream side in the rotation direction of the heat roller 2 of the guide member 13 extends to the vicinity of the surface of the heat roller 2, and the downstream side wall portion 13b upstream of the gap with the heat roller 2 at the lower end. It is larger than the side wall portion 13a. Therefore, the air flow traveling downward by the blowing means 12 passes through the location of the temperature sensor 11 and flows downstream in the rotation direction of the heat roller 2 in the vicinity of the surface of the heat roller 2.

  In this way, in the non-contact type temperature detecting device 10 that detects the surface temperature of the member, the air blowing means 12 and the guide member that guides the air flow obtained by the air blowing means 12 to the temperature detecting portion 11 a of the temperature sensor 11. 13, it is possible to prevent dust and debris from being scattered at the location of the temperature detection unit 11 a due to the air flow from the air blowing means 12. As a result, the thermal energy of the member surface necessary for detecting the surface temperature of the member reaches the temperature detection unit 11a without being affected by dust and dirt. Therefore, it is possible to obtain the temperature detection device 10 that can perform more appropriate temperature detection.

  In the present invention, since the temperature detecting device 10 is mounted on the fixing device 1 in order to detect the surface temperature of the heat roller 2 as a fixing member, dust and dust such as toner and paper dust are scattered and the temperature is increased. It is possible to obtain a high-performance fixing device 2 that includes the temperature detection device 10 that can prevent adhesion to the detection unit and can perform appropriate temperature detection.

  In the fixing device 1 configured as described above, since the temperature detection device 10 is disposed above the heat roller 2, the toner and paper dust remaining around the temperature detection device 10 are added to the air flow from the blowing unit 12. Their own weights act, and it becomes difficult to reach the temperature detection unit 11a. As a result, the accuracy of temperature detection by the temperature detection device 10 can be improved, so that more accurate temperature control can be performed in the fixing device 1.

  Further, in the fixing device 1 configured as described above, since the air blowing means 12 of the temperature detection device 10 is driven when the heat roller 2 rotates, toner and paper dust are scattered by the air flow generated near the surface by the rotation of the heat roller 2. It can suppress becoming easy to do. In this way, by driving the air blowing means 12 only when the toner and paper dust are likely to be scattered, the accuracy of temperature detection can be increased, and the power consumption of the fixing device 1 can be reduced. It becomes possible.

  Next, a detailed configuration of the fixing device equipped with the temperature detection device according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic vertical sectional front view of a fixing device equipped with a temperature detection device. In the figure, solid arrows indicate the rotation direction of the heat roller and pressure roller, and white arrows indicate the direction of air movement. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIG. 1, the same reference numerals are assigned to the same components as those of the first embodiment. The description will be omitted.

  In the second embodiment, as shown in FIG. 2, the guide member 14 of the temperature detection device 10 causes the air flow passing through the inside by the blower 12 as the heat roller 2 that is a fixing member approaches the heat roller 2. The shape will be directed downstream in the rotation direction. That is, in FIG. 2, the guide member 14 that is located above the heat roller 2 and extends downward from the location of the air blowing means 12 provided above the temperature sensor 11 moves to the right as it approaches the heat roller 2 that rotates clockwise. Is curved.

  In this manner, the guide member 14 of the temperature detection device 10 has a shape in which the air flow is directed downstream in the rotation direction of the heat roller 2 as it approaches the heat roller 2. The air flow can be sent out from the air blowing means 12 without countering the slight circumferential air flow near the surface. As a result, the toner and paper dust remaining around the temperature detection device 10 are moved away from the temperature detection device 10 without being disturbed and approaching the temperature detection unit 11a.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the object whose temperature is detected by the temperature detection device 10 is not limited to the heat roller 2 that is a fixing member, but may be the pressure roller 3 that is a pressure member. Moreover, you may provide the temperature detection apparatus 10 one each with respect to these both members. Further, the target member that performs temperature detection by the temperature detection device 10 is not limited to the member that constitutes the fixing device 1 as in the present embodiment, and may be a component member of another device.

  INDUSTRIAL APPLICABILITY The present invention can be used in general non-contact temperature detecting devices that detect the surface temperature of members.

1 is a schematic vertical sectional front view of a fixing device equipped with a temperature detecting device according to a first embodiment of the present invention. FIG. 6 is a schematic vertical sectional front view of a fixing device equipped with a temperature detection device according to a second embodiment of the present invention.

Explanation of symbols

1 Fixing device 2 Heat roller (fixing member)
3 Pressure roller (Pressure member)
4 Halogen lamp 10 Temperature detection device 11 Temperature sensor 11a Temperature detection unit 12 Blowing means 13, 14 Guide member

Claims (5)

In a non-contact type temperature detection device that detects the surface temperature of a member,
A temperature detection apparatus comprising: a blowing unit; and a guide member for guiding an air flow obtained by the blowing unit to a temperature detection unit.   A fixing device comprising the temperature detecting device according to claim 1 mounted to detect a surface temperature of a fixing member and / or a pressure member.   The fixing device according to claim 2, wherein the temperature detection device is disposed above the fixing member and / or the pressure member.   The guide member of the temperature detection device has a shape in which the air flow is directed downstream in the rotation direction of the fixing member or the pressure member as it approaches the fixing member or the pressure member. The fixing device according to claim 2 or 3.   5. The fixing device according to claim 2, wherein the blowing unit of the temperature detection device is driven when the fixing member or the pressure member rotates.

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