JP5021329B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine thereof, and a fixing device equipped therewith.

Conventionally, a copying machine, an image forming apparatus such as a printer, a fixing device short on-demand rise time, a fixing member using the endless film, and the pressure member, a heating means such as a ceramic heater Provided, and a heating means is installed inside the fixing member to contact the pressure member through the film-like fixing member to form a nip portion, and the fixing member is heated. In such a fixing device, when the toner image carried on the recording material conveyed toward the nip portion passes through the nip portion, the toner image is fixed on the recording material by applying heat and pressure. ing. Patent Document 1 is an example of a fixing device using a film-like fixing member.

JP 2002-6656 A

  In a fixing device using a film-like fixing member as in Patent Document 1, generally, a pressure member is rotationally driven by a driving unit, and the fixing member is driven and rotated by frictional force with the pressure member and frictional force with a recording material. Since the rotation behavior is difficult to stabilize and the start-up performance is good, the temperature at the nip is excessive if the fixing member stops rotating due to a drive system failure or frictional force. Therefore, there is a demand for detection of the behavior of the fixing member.

  An object of the present invention is to propose a fixing device and an image forming apparatus capable of detecting a behavior change factor of a fixing member that causes deformation or tearing of the fixing member.

  SUMMARY OF THE INVENTION An object of the present invention is to propose a fixing device and an image forming apparatus capable of preventing deformation and tearing of a fixing member and improving durability.

In order to achieve the above object, according to the first aspect of the present invention, a toner image on a recording material is heated and melted and a flexible fixing member is contacted with a pressure member via the fixing member to form a nip portion. For this purpose, the contact member provided inside the fixing member, the contact member is heated, the heating unit disposed above the contact member, and the radiant heat from the heating unit is reflected to the contact member. A reflecting member to be incident, a rotational behavior of the fixing member, and a behavior detecting means that is disposed substantially on the outer peripheral side of the fixing member and is located immediately above the nip portion, a rotating member that contacts the fixing member, and a rotating member The behavior detecting means is a protrusion detecting means for detecting the protrusion of the rotating member .

According to a sixth aspect of the present invention, in the fixing device according to any one of the first to fifth aspects, the fixing member is a cylindrical and thin endless film.

According to a seventh aspect of the present invention, in the fixing device according to any one of the first to sixth aspects, the fixing member has a fluorine surface layer.

According to an eighth aspect of the present invention, in the fixing device according to any one of the first to seventh aspects, the surface on which the fixing member and the contact member are in sliding contact is coated with fluorine.

According to a ninth aspect of the present invention, in the fixing device according to any one of the first to eighth aspects, the behavior detecting means is an optical detecting means for detecting the rotation of the rotating member.

According to a tenth aspect of the present invention, in the fixing device according to any one of the first to ninth aspects, the detecting device includes a reflection means for detection provided on the rotating member, and the behavior detection means is a reflection that detects the detection reflection means. It is a detection means.

According to a second aspect of the present invention, the toner image on the recording material is heated and melted, and the fixing member has flexibility, and the inside of the fixing member is in contact with the pressure member via the fixing member to form a nip portion. An abutting member provided on the abutting member, a heating means for heating the abutting member, a reflecting member for reflecting the radiant heat from the heating means to be incident on the abutting member, and fixing. Rotation behavior of the member is detected, and there is a behavior detection means that is located almost directly above the nip portion and close to the outer peripheral side of the fixing member, a rotating member that contacts the fixing member, and a protrusion provided on the rotating member. The behavior detecting means is a displacement detecting means for detecting the displacement of the rotating member in the contact direction with the fixing member.

According to an eleventh aspect of the present invention, there is provided the fixing device according to the second aspect, wherein the fixing member has a protrusion provided on the fixing member, and the displacement detecting means detects a displacement amount of the rotating member due to the protrusion.

According to a third aspect of the present invention, there is provided a fixing member which heats and melts a toner image on a recording material and has a flexibility and a pressing member via the fixing member to form a nip portion . and the abutment member provided therein, heating the contact member, and a heating means disposed above the contact member, and reflects radiant heat from the heating means, and the reflection member to be incident on the contact member , The rotation behavior of the fixing member is detected, and the behavior detection means that is located almost directly above the nip portion and close to the outer peripheral side of the fixing member, the rotating member that contacts the fixing member, and the fixing member The protrusion has a protrusion provided on the fixing member, and the behavior detecting means detects a pressure displacement before and after the rotating member is pushed up by the protrusion as a contact pressure fluctuation of the rotating member to the fixing member. It is the pressure detection means to do.

According to a fourth aspect of the present invention, a toner image on a recording material is heated and melted and a fixing member having flexibility and a pressure member via the fixing member to form a nip portion to form a nip portion. An abutting member provided on the abutting member, a heating means for heating the abutting member, a reflecting member for reflecting the radiant heat from the heating means and making it incident on the abutting member; The rotation behavior of the fixing member is detected, and a behavior detecting means that is disposed substantially on the outer peripheral side of the fixing member, substantially above the nip portion, a rotating member that contacts the fixing member, and a protrusion provided on the fixing member. The behavior detecting means is a rotational load detecting means for detecting a torsional torque of the shaft of the rotating member when the rotating member rides on the protrusion as a rotational load fluctuation of the rotating member.

The invention of claim 12, in the fixing device according to any one of claims 1 to 11, the rotary member is characterized in that it is disposed outside the fixing member.

According to the fifth aspect of the present invention, the toner image on the recording material is heated and melted, and the fixing member has flexibility, and the inside of the fixing member is in contact with the pressure member via the fixing member to form a nip portion. An abutting member provided on the abutting member, a heating means for heating the abutting member, a reflecting member for reflecting the radiant heat from the heating means to be incident on the abutting member, and fixing. Rotation behavior of the member is detected, and has a behavior detection means that is disposed substantially on the outer peripheral side of the fixing member, and a rotation member that comes into contact with the fixing member. The behavior is detected, and the rotating member is arranged inside the fixing member.

The invention of claim 1 3, in the fixing device according to any one of claims 1 to 12, the rotating member is characterized in that it is mounted within the fixed retention member fixing member .

Allowable invention of claim 1 4, in the fixing device according to any one of claims 1 to 1 3, the heating means includes a heating element which generates heat by being energized, the detection result by the behavior detecting means When it is out of the range, the power supply to the heating element is stopped.

The invention of claim 1 5, as a fixing device for fixing a recording material to heat and pressure to the toner image carried on the recording material is fed, according to any one of claims 1 to 1 4 It has a fixing device.

  According to the present invention, a toner image on a recording material is heated and melted, and a fixing member having flexibility and a pressure member through the fixing member to form a nip portion are formed inside the fixing member. Since it has a contact member provided, a heating means for heating the contact member, and a behavior detection means for detecting the rotation behavior of the fixing member, the behavior change factors of the fixing member that cause deformation and tearing of the fixing member are provided. Can be detected.

  According to the present invention, since the temperature detecting means for detecting the temperature change of the fixing member is provided, the behavior change factor of the fixing member causing the deformation or tearing of the fixing member is detected by the temperature of the fixing member. Therefore, the temperature rise of the fixing member can be accurately detected.

  According to the present invention, the rotating member that contacts the fixing member is provided, and the behavior of the rotating member is detected by the behavior detecting means. Therefore, the behavior can be detected without applying a load to the fixing member.

  According to the present invention, since the behavior detection unit is an optical detection unit that detects the rotation of the rotating member, the behavior can be detected without applying a load to the fixing member based on the rotation and rotation speed of the fixing member. .

  According to the present invention, the reflecting member is provided on the rotating member, and the reflecting member is detected by the reflecting detecting means serving as the behavior detecting means. Therefore, the fixing member and the rotating member are rotated and The rotational speed can be detected.

  According to the present invention, since the protrusion is provided on the rotating member, and the protrusion is detected by the protrusion detecting means serving as the behavior detecting means, the rotation of the fixing member is inexpensive and without applying a load to the fixing member and the rotating member. And the rotational speed can be detected.

  According to the present invention, since the behavior detecting unit is a displacement detecting unit that detects the displacement of the rotating member in the contact direction with the fixing member, it is possible to detect the rotation and eccentricity (blur) state of the fixing member.

  According to the present invention, since the behavior detecting means is a pressure detecting means for detecting the contact pressure fluctuation of the rotating member to the fixing member, the rotation and eccentricity (blur) states of the fixing member can be detected. The shape of the fixing member can be simplified as compared with the case where the protrusion is provided on the fixing member.

  According to the present invention, since the behavior detection unit is a rotation load detection unit that detects a rotation load variation of the rotation member, the rotation and rotation of the fixing member can be detected.

  According to the present invention, since the rotating member is arranged outside the fixing member, it is possible to detect a behavior change factor of the fixing member that causes deformation or breakage of the fixing member and to simplify the fixing device. Can do.

  According to the present invention, since the rotating member is disposed inside the fixing member, it is possible to detect a behavior change factor of the fixing member that causes deformation or breakage of the fixing member while reducing the influence from devices other than the fixing device. Thus, the detection accuracy can be improved and the apparatus can be downsized.

  According to the present invention, since the rotating member is mounted on the holding member fixed inside the fixing member, the detection accuracy can be improved while reducing the influence from devices other than the fixing device, and the fixing device can be improved. Can be simplified and the apparatus can be downsized.

  According to the present invention, when the detection result by the behavior detecting unit is out of the allowable range, the heating unit has or is energized, the energization to the heating element that generates heat is stopped. Since tearing can be prevented, the durability of the apparatus can be improved.

  According to the present invention, it is possible to detect the behavior of a fixing member of a fixing device that applies heat and pressure to a toner image carried on a recording material that has been passed through to fix the recording material. Can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description thereof will be simplified or omitted as appropriate.

  First, the overall configuration and operation of the image forming apparatus including the fixing device 20 which is a characteristic configuration of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an apparatus main body of a copying machine as an image forming apparatus, 2 denotes an original reading unit that optically reads image information of an original D, and 3 denotes exposure light based on image information read by the original reading unit 2. An exposure unit for irradiating L on the photosensitive drum 5 serving as an image bearing member, 4 an image forming unit for forming a toner image (image) on the photosensitive drum 5, and 7 a toner formed on the photosensitive drum 5. A transfer unit for transferring the image to the recording material P, 10 is a document conveying unit for conveying the set document D to the document reading unit 2, 12 to 14 are paper feeding units in which the recording material P such as transfer paper is stored, 20 Is a fixing device for fixing an unfixed toner image on the recording material P, 21 is a fixing film as a fixing member installed in the fixing device 20, and 31 is a pressure roller as a pressure member installed in the fixing device 20. Respectively.

  With reference to FIG. 1, an operation during normal image formation in the image forming apparatus will be described. The document D is transported from the document table in the direction of the arrow in the figure by the transport roller of the document transport unit 10 and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads the image information of the document D passing above.

  The optical image information read by the document reading unit 2 is converted into an electrical signal and then transmitted to the exposure unit 3 (writing unit). From the exposure unit 3, exposure light L such as laser light based on the image information of the electrical signal is emitted toward the photosensitive drum 5 of the image forming unit 4.

  In the image forming unit 4, the photosensitive drum 5 rotates in the clockwise direction in the drawing, and corresponds to image information on the photosensitive drum 5 through a predetermined image forming process (charging process, exposure process, development process). An image (toner image) is formed. The image formed on the photosensitive drum 5 is transferred onto the recording material P conveyed by a registration roller (not shown) in the transfer unit 7.

  The recording material P conveyed to the transfer unit 7 follows the following path. Of the plurality of paper feeding units 12, 13, and 14 of the image forming apparatus main body 1, one paper feeding unit is automatically or manually selected (for example, the uppermost paper feeding unit 12 is selected). ). Then, the uppermost sheet of the recording material P stored in the paper feeding unit 12 is transported toward the position of the transport path K. The transported recording material P passes through the transport path K and reaches the position of the registration roller. The recording material P that has reached the position of the registration roller is conveyed toward the transfer unit 7 at the same timing in order to align with the image formed on the photosensitive drum 5.

  The recording material P after the transfer process reaches the fixing device 20 through the conveyance path K after passing through the position of the transfer unit 7. The recording material P that has reached the fixing device 20 is conveyed between the fixing film 21 and a pressure roller 31 that is rotationally driven by a drive motor M1 serving as a driving means, and the pressure roller 31 (see FIG. 2) rotates. The unfixed toner image T is melted and fixed by the heat received from the fixing film 21 driven by the driving and the pressure received from both the members 21 and 31. The recording material P on which the image is fixed is delivered from a nip portion N formed between the fixing film 21 and the pressure roller 31 and then discharged from the image forming apparatus main body 1. Thus, a series of image forming processes is completed.

  Next, the configuration and operation of the fixing device 20 mounted on the image forming apparatus main body 1 will be described in detail. 2 and 3, the fixing device 20 includes a fixing film 21 as a fixing member extended in the width direction W of the recording material P, a heating plate 22 as a contact member, and a reflecting plate as a reflecting member. 23, a holding member 24, an infrared heater 25 as a heating means, a pressure roller 31 as a pressure member, and guide plates 35 and 37.

  As shown in FIG. 2, the pressure roller 31 is formed by forming an elastic layer 33 on a cored bar 32. The elastic layer 33 of the pressure roller 31 is formed of a material such as fluorine rubber, silicone rubber, or foamable silicone rubber. Note that a thin release layer (tube) made of PFA or the like may be provided on the surface layer of the elastic layer 33. The pressure roller 31 is in pressure contact with the fixing film 21 to form a desired nip portion N between both members. The pressure roller 31 is rotatably installed on a side plate (fixed position) (not shown) of the fixing device 20 via a bearing. The pressure roller 31 is configured to be rotationally driven by a drive motor 31 in an arrow direction (counterclockwise direction) in FIG.

  The fixing film 21 is a thin and flexible endless film, and rotates in the direction of an arrow (clockwise) in FIG. As a material of the fixing film 21, polyimide, polyamide, fluororesin, metal, or the like can be used. In order to ensure releasability (peelability) with respect to toner T (toner image), PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), polyimide, polyetherimide, PES is provided on the surface layer of the fixing film 21. A release layer made of (polyether sulfide) or the like can also be formed. By using the fixing film 21 having a low heat capacity as the fixing member, it is possible to provide the on-demand fixing device 20 having a very short rise time. The fixing film 21 is rotated in the direction of the arrow in FIG. 2 (driven rotation) by the frictional force with the pressure roller 31 that is driven to rotate.

  Inside the fixing film 21 (inner peripheral surface side), an infrared heater 25, a heating plate 22, a reflecting plate 23, a holding member 24, and the like are arranged. The fixing film 21 is pressed by the heating plate 22 to form a nip portion N between the fixing film 21 and the pressure roller 31.

  The heating plate 22 is a metal plate (or a plate made of ceramic or polyimide resin) having a thickness of about 0.1 mm, and is heated by radiant heat from the infrared heater 25 and is pressed through the fixing film 21. A desired nip portion N is formed in contact with the roller 31. As shown in FIG. 3, the heating plate 22 extends in the width direction W, and is supported and fixed to the holding member 24 so as to face the opening 24 </ b> A formed in the holding member 24.

  In the present embodiment, as shown in FIG. 2, the opposed surface 22A of the heating plate 22 (the surface facing the pressure roller 31) is formed in a planar shape. As a result, the shape of the nip portion is substantially parallel to the image surface of the recording material P, and the adhesion between the fixing film 21 and the recording material P is improved, so that the fixing property is improved and the nip portion N passes through. The problem of curling and wrinkling in the recording material P to be reduced is also reduced. Further, since the curvature of the fixing film 21 on the exit side of the nip portion N is increased, the recording material P sent out from the nip portion N can be easily separated from the fixing film 21. The heating plate 22 may be coated with a fluororesin on the surface where the fixing film 21 is in sliding contact. As a result, it is possible to reduce wear on the inner peripheral surface of the fixing film 21 that is in sliding contact with the heating plate 22 fixedly supported by the fixing device 20.

  An absorbing member that absorbs infrared rays may be provided on the opposing surface 22B (on the side facing the infrared heater 25) of the heating plate 22. Specifically, black coating can be applied to the facing surface 22B of the heating plate 22. Thereby, the infrared absorption rate in the heating plate 22 is improved, and the heating efficiency of the heating plate 22 is increased.

  The reflection plate 23 extends in the width direction W on the side opposite to the side facing the heating plate 22 with respect to the infrared heater 25 (above the infrared heater 25 in FIG. 2), and is separated from the infrared heater 25. Are arranged. That is, the reflection plate 23 is disposed at a position opposite to the heating plate 22 with the infrared heater 25 interposed therebetween. The reflection plate 23 is a mirror finish on aluminum and is configured / arranged to reflect infrared rays emitted from the infrared heater 25 toward the heating plate 22. For this reason, it is possible to prevent the radiant heat (infrared rays) from the infrared heater 25 from escaping to the side opposite to the heating plate 22. That is, since the radiant heat (infrared rays) from the infrared heater 25 toward the reflection plate 23 enters the heating plate 22 reflected by the reflection plate 23, the heating efficiency of the heating plate 22 is increased.

  In the present embodiment, the reflecting plate 23 is installed at a position separated from the infrared heater 25. However, a part of the glass tube constituting the infrared heater 25 (the side opposite to the side facing the heating plate 23) is plated with gold. A metal such as aluminum may be deposited. Also in this case, the heating efficiency of the heating plate 22 is increased because the gold plating or aluminum deposition portion applied to the glass functions as a reflective film (reflective member).

  3 and 4, the holding member 24 is long in the width direction W and is made of a heat-resistant resin material. Both ends of the holding member 24 penetrate the inner space of the fixing film 21 in the width direction W, and the fixing device 20 is not illustrated. It is supported by holders 27 and 27 as second holding members mounted on the side plates. The holding member 24 integrally holds the heating plate 22, the reflecting plate 23, and the infrared heater 25. In particular, the infrared heater 25 is held by the holding member 24 via holders 27 and 27 whose both ends 25A and 25B are arranged in the width direction W. Holders 27 and 27 are screwed to both ends of the holding member 24 in the width direction. Each holder 27 is provided with a hole that is gently inserted into the end portions 25 </ b> A and 25 </ b> B of the infrared heater 25. Each holder 27 is attached to a side plate (not shown). However, as shown in FIG. 5, the holding member 24 ( Only the infrared heater 25 can be detached from the fixing device 20).

  Compression springs 28 and 28 are provided at both ends of the holding member 24 in the width direction, respectively. Thereby, the heating plate 22 is urged toward the pressure roller 31 to form a desired nip portion N.

  As shown in FIG. 2, the holding member 24 is formed to guide the fixing film 21. That is, the holding member 24 has a circular outer peripheral surface so that the circular posture of the flexible fixing film 21 can be maintained to some extent. In the present embodiment, the holding member 24 has a cylindrical shape so that the heating plate 22, the reflection plate 23, and the infrared heater 25 are accommodated therein, and the outer peripheral surface thereof is circular. Thereby, deterioration and breakage due to deformation of the fixing film 21 can be reduced.

  A guide plate 35 that guides the recording material P conveyed toward the nip portion N is disposed on the entrance side of the nip portion N that is a contact portion between the fixing film 21 and the pressure roller 31. On the outlet side of the nip portion N, a guide plate 37 for guiding the recording material P fed from the nip portion N is disposed. Both guide plates 35 and 37 are fixed to the frame (housing) of the fixing device 20.

  As shown in FIG. 3, the infrared heater 25 is disposed inside the holding member 24, and is fixed to the holder 27 of the fixing device 20 via both end portions 25 </ b> A and 25 </ b> B. The infrared heater 25 includes a heating element 250 that generates heat when power controlled by a power source (not shown) of the image forming apparatus main body 1 is supplied, and a glass sealing tube 252 that encloses the heating element 250. The heating plate 22 is heated by the heat generated by the heating element 250. The fixing film 21 is heated by a heated heating plate 22, and heat is applied to the unfixed toner image T on the recording material P from the surface thereof. The infrared heater 25 is controlled to be energized so that the surface temperature of the fixing film 21 becomes the fixing temperature, and is also controlled to be de-energized when the recording material P is not passed.

  As the infrared heater, a halogen heater or a carbon heater can be used. In particular, when a carbon heater is used, the degree of freedom of on / off control is increased as compared to when a halogen heater is used. Specifically, even if the control for turning off the energization is repeated before the duty of the heater reaches 100%, the output decrease with time is reduced without disconnection. Further, when a carbon heater is used, its shape is optimized, and the amount of radiant heat generated in a direction facing the heating plate 22 reflecting plate 23 is a direction perpendicular to that direction (the left-right direction in FIG. 1). It is preferable to form so that it may become larger than the calorie | heat amount of the radiant heat emitted to. Thereby, since the heat generated from the infrared heater 25 can be concentrated on the heating plate 22, the heating efficiency of the heating plate 22 is increased. Further, in the case of a carbon heater, since the heat generation performance from energization to non-energization is faster than that of a halogen heater or the like, it is possible to improve start-up performance during on-demand.

  The fixing device 20 configured as described above operates as follows. When the power switch of the image forming apparatus main body 1 is turned on, power is supplied to the infrared heater 25, and the rotational driving of the pressure roller 31 in the direction of the arrow in FIG. Thereby, the fixing film 21 is also driven (rotated) in the direction of the arrow in FIG. 2 by the frictional force with the pressure roller 31. Thereafter, the recording material P is fed from the paper feeding units 12 to 14, and an unfixed toner image T is carried on the recording material P by the image forming unit 4. The recording material P carrying the toner image T is conveyed in the direction of the arrow Y10 in FIG. 2 while being guided by the guide plate 35, and is sent to the nip portion N of the fixing film 21 and the pressure roller 31 that are in a pressure contact state. Is done. The unfixed toner image T is fixed on the surface of the recording material P by the heating by the fixing film 21 heated by the heating plate 22 and the pressing force of the heating plate 22 (fixing film 21) and the pressure roller 31. . The recording paper P that has been fixed is sequentially sent out from the nip portion N and conveyed in the direction of the arrow Y11.

  Next, although the form concerning the characteristic part of the fixing device 20 of the present invention will be described later, the same reference numerals are given to the same members or parts having the same function in each form, and redundant explanation is saved.

(First embodiment)
As shown in FIG. 6A, the present embodiment includes a temperature detection unit 40 that detects a temperature change of the fixing film 21 as a behavior detection unit that detects the rotational behavior of the fixing film 21. The temperature detection means 40 is a known one such as a thermistor, and is configured to input temperature information as behavior detection information to the control means 100 to which the fixing power supply unit 101 is connected. The temperature detection means 40 is disposed on the opposite side of the heating body 22 with the infrared heater 25 in between. In this embodiment, since the heating plate 22 is disposed in the nip portion N below the infrared heater 25, the temperature detecting means 40 is positioned almost directly above the nip portion N in FIG. 21 are arranged close to each other from the outside.

  The control means 100 is connected to the heating element 250 of the infrared heater 25 via the power supply unit 101 and receives a drive signal from the drive motor M1. The control means 100 is constituted by a well-known computer, and a fixing temperature and a set temperature T1 as a behavior determination criterion are set in advance in a ROM (not shown). The set temperature T1 is set to a predetermined temperature corresponding to the position of the temperature detecting means 40.

  When the sheet passing information and the driving information are input, the control unit 100 controls the power supply unit 101 to control the energization of the infrared heater 25 so that the temperature of the fixing film 25 becomes the fixing temperature. If the detected temperature T from the temperature detecting means 40 is lower than the set temperature T1 when drive information is input, the power supply unit 101 is controlled to stop energization of the heating element 250.

  Here, the temperature change of the fixing film 21 will be described. When the heating plate 22 is heated by the radiant heat from the heating element 250, the fixing film 21 is heated in the vicinity of the nip portion. In FIG. 6A, since the fixing film 21 rotates in the clockwise direction, the temperature is higher in the nip portion N and in the vicinity of the downstream side in the recording material conveyance direction than the nip portion N, and the fixing film 21 rotates. The temperature decreases as it advances (away from the heating element 22), and the temperature on the upstream side in the recording material conveyance direction from the nip portion N becomes the lowest.

  Further, as shown in FIG. 6B, the temperature of the fixing film 21 rises at the initial stage of heating. However, if the amount of heat from the infrared heater 25 is constant, a constant temperature is obtained when the balance between heating and heat dissipation is balanced. It becomes. In other words, if the fixing film 21 is moving normally, if the temperature is detected at a certain position, the temperature becomes a constant value. However, when there is an abnormality in the behavior of the fixing film 21 such as when the fixing film 21 is stopped or the moving speed is slow, the detection temperature is lowered.

  The inventor has determined the behavior of the fixing film 21 from the temperature displacement of the fixing film 21. In other words, in this embodiment, a temperature that is constant at the installation position of the temperature detecting means 40 is obtained on a trial basis, the temperature is set as the set temperature Т1, and when the detected temperature T is lower than the set temperature T1, the fixing film It was determined that 21 was not moving normally, and power supply to the heating element 250 was stopped.

  By adopting such a configuration, a behavior detecting means for detecting a behavior change factor of the fixing film 21 that causes deformation and tearing of the fixing film 21 and a temperature detecting means 40 for detecting a temperature change of the fixing film 21 are provided. The temperature change of the fixing film 21 can be detected with high accuracy. Further, when the detected temperature T is lower than the set temperature T1, energization control for stopping energization of the heating element 250 is executed by the control means 100. For this reason, it is possible to prevent a temperature rise that ends the allowable limit at the nip portion N, and to prevent the fixing film 21 from being deformed or torn. Therefore, the durability of the apparatus can be improved while maintaining the rising performance of the fixing apparatus 20. Can do.

(Second Embodiment)
In this embodiment, as shown in FIG. 7A, the temperature detecting means 40 is disposed outside the fixing film 21 in the vicinity of the nip portion N that is downstream of the nip portion N in the recording material moving direction. In this case, the constant temperature detected by the temperature detection means 40 is higher than that in the first embodiment, so that the set temperature T2 set in the control means 100 as shown in FIG. <T2).

  As described above, when the temperature detecting means 40 is arranged on the downstream side of the nip portion N in the recording material moving direction, the temperature can be detected in a relatively high temperature region immediately after the heating, and the airflow in the apparatus as compared with the first embodiment. The detection accuracy can be improved.

(Third embodiment)
In this embodiment, as shown in FIG. 8A, the temperature detecting means 40 is arranged in the vicinity of the nip portion N that is upstream of the nip portion N in the recording material moving direction. In this case, the constant temperature detected by the temperature detection means 40 is lower than that in the first embodiment, and therefore, the set temperature T3 set in the control means 100 as shown in FIG. > T3).

  As described above, when the temperature detecting means 40 is arranged on the upstream side in the recording material moving direction of the nip portion N, detection in a relatively low temperature range can be performed, and the temperature detecting means 40 having a low temperature detection area can be used. The cost can be reduced and it is difficult to be affected by heat, so that the durability of the temperature detecting means 40 is improved and the durability of the apparatus is improved.

  Since the recording material P is conveyed from the upstream side of the nip portion N toward the nip portion N, an air flow may be generated between the recording material P upstream of the nip portion and the fixing film 21. Since the generation of such an air current causes a change in the detection environment of the temperature detection means 40, a guide plate 38 may be installed between the temperature detection means and the recording material P on the upstream side of the nip portion.

  By installing such a guide plate 38, the air flow from the recording material P to the temperature detection means 40 can be blocked, so that the detection environment is stabilized and the temperature detection accuracy can be increased.

(Fourth embodiment)
In this embodiment, as shown in FIG. 9A, the temperature detecting means 40 is disposed inside the fixing film 21 to detect the temperature of the fixing file 21. The temperature detecting means 40 may be attached to either the heating body 22 or the holding member 24 directly or via a bracket or the like and disposed close to the fixing film 21 inside the fixing file 21. When the temperature detection means 40 is arranged on the inner side of the fixing film 21, the constant temperature detected by the temperature detection means 40 is less affected by the airflow and is higher than that of the first embodiment, and therefore, FIG. As shown in (b), the set temperature T4 set in the control means 100 is (T1 <T4).

  As described above, when the temperature detection means 40 is arranged inside the fixing film 21, it is difficult to be affected by the airflow and heat from devices other than the fixing device 20, so that the detection environment is stabilized and the temperature detection accuracy can be improved.

  In the first embodiment to the fourth embodiment, the temperature detection unit 40 assumes that the fixing film 21 has a poor behavior when the temperature falls from the set temperature T1 to T4. For example, the set temperature T1 to T4. If the temperature rises more than that, it may be determined that the fixing film 21 has been heated excessively, and power supply to the heating element 250 may be immediately stopped.

(Fifth embodiment)
As shown in FIG. 10, this embodiment includes a roller 50 as a rotating member that comes into contact with the fixing film 21 from the outside, and an optical detection hand 60 as a behavior detecting unit that detects the rotation of the roller 50 as a behavior. The roller 50 is rotatably supported at the tip of an arm 52 that is swingably supported by a fulcrum 51 and is in contact with the surface of the fixing film 21 by the arm 51 and its own weight.

  Since the fixing film 21 also has a space between the fixing member 21 and the support member 24 except for the portion sandwiched and supported by the nip portion N, when the pressure roller 31 is driven and rotated, In parts other than the nip part N, it is rotating while vibrating so as to wave. In the present embodiment, this wave phenomenon (vibration) generated when the fixing film 21 is rotating is detected as a displacement of the roller 50 to determine whether or not the fixing film 21 is rotating normally. . For this reason, the roller 50 is disposed so as to contact the fixing film 21 at a place where there is no backup member that contacts the roller 5 from the inside of the fixing film 21 so that the wave of the fixing film 21 can be easily detected. ing.

  The optical detection means 60 is a reflection type optical sensor that irradiates the outer peripheral surface of the roller 50 with detection light, receives the reflected light, and detects the swing displacement amount of the roller 50, and is connected to the line control means 100A. Has been. The control unit 100 </ b> A is configured by a known computer, and a detection signal is input from the optical detection unit 60. Similar to the control unit 100, the control unit 100A is connected to the heating element 250 of the infrared heater 25 via the power supply unit 101, and receives a drive signal from the drive motor M1. In the ROM (not shown) of the control unit 100A, a fixing temperature and a reference displacement amount U1 serving as a behavior determination reference are set in advance.

  When the sheet passing information and the driving information are input, the control unit 100A controls the power supply unit 101 to control energization of the infrared heater 25 to the heating element 250. The control unit 100A detects the amount of displacement of the roller 52 from the detection signal from the optical detection unit 60 based on the intensity of light reflection. When the roller 50 is displaced when drive information is input, the fixing film 21 is detected. If the roller 50 is not displaced or the amount of displacement is small, it is determined that the fixing film 21 is not rotating or the rotation speed is extremely slow, and the heating element 250 is rotated. The power supply unit 101 is controlled so as to stop energization.

  Thus, the rotatable roller 50 is brought into contact with the fixing film 21 and the behavior of the roller 50 is detected by the optical detection means 60. Therefore, the behavior can be detected without applying a load to the fixing film 21. it can.

(Sixth embodiment)
In the present embodiment, as shown in FIG. 11, the position of the roller 50 </ b> A serving as a rotating member is fixed, and the rotation of the roller 50 </ b> A is detected by the optical detection means 61. In this embodiment, the roller 50 </ b> A is provided so as to be able to rotate integrally with a shaft 55 that is rotatably supported by a frame (not shown) of the fixing device, and is in contact with the outer peripheral surface of the fixing film 21. In this embodiment, the roller 50A is configured to rotate at a fixed position without swinging.

  The optical detection means 61 is a reflective optical sensor that irradiates the side surface of the roller 50A with detection light and receives the reflected light to detect the rotation of the roller 50A. A heating element 250 of the infrared heater 25 is connected to the control means 100A via the optical detection means 61 and the power supply unit 101, and a drive signal is input from the drive motor M1. In the ROM (not shown) of the control unit 100A, a fixing temperature and a reference rotational displacement amount R1 that is a behavior determination reference are set in advance.

  In this embodiment, the control unit 100A detects the presence or absence of rotation of the roller 50A from the detection signal from the optical detection unit 61, and when the driving information is input, if the roller 50A is rotating, the fixing film 21 is If it is determined that the roller 50A is not rotating or is rotating slowly, it is determined that the fixing film 21 is not rotating or its rotating speed is extremely slow, and the heating element 250 is energized. The power supply unit 101 is controlled to stop the operation.

  Even with this configuration, the presence or absence of rotation of the fixing film 21 detects the behavior of the roller 50 </ b> A by the optical detection means 61, so that the behavior can be detected without applying a load to the fixing film 21.

  In this embodiment, a reflective sensor is used as the optical detection means 61. However, a transmissive photosensor is used, and a known slit plate (not shown) is provided on the shaft 55 that rotates integrally with the roller 50A to detect the rotation of the roller 50. You may make it do.

(Seventh embodiment)
In this embodiment, as shown in FIGS. 13 and 14, the reflecting member 56 is provided on the side surface of the roller 50 </ b> A, and the optical detection means 61 is disposed at a position where the reflecting member 56 is detected. In this case, in the control unit 100A, a value when the reflection member 56 is detected by the optical detection unit 61 is set as a reference value R2 as a behavior determination reference. When the reference value R2 is not detected, the fixing film The power supply unit 101 may be controlled to stop energization of the heating element 250 by determining that the motor 21 is not rotating or the rotation speed thereof is extremely slow.

  With such a configuration, the behavior of the fixing film 21 can be detected at low cost and without applying a load to the fixing film 21 and the roller 50, and the durability of the fixing film 21 and the apparatus is good. Become.

(Eighth embodiment)
In this embodiment, FIG. 15 and FIG. 16 are provided with a protrusion 57 when extending in the axial direction on the side surface of the roller 50 instead of the reflecting member 56, and an optical detection means 61 is disposed at a position where the protrusion 57 is detected. To function as. In this case, in the control unit 100A, the value when the projection 57 is detected by the optical detection unit 61 is set as the reference value R3 as the behavior determination reference. If the reference value R3 is not detected, the fixing film 21 is set. May be determined to be not rotating, or the rotation speed thereof is extremely slow, and the power supply unit 101 may be controlled to stop energization of the heating element 250.

  With such a configuration, the behavior of the fixing film 21 can be detected at low cost and without applying a load to the fixing film 21 and the roller 50, and the durability of the fixing film 21 and the apparatus is good. Become.

(Ninth embodiment)
In this embodiment, as shown in FIGS. 17 and 18, a displacement detecting means 62 for detecting the displacement of the roller 50 in the contact direction with the fixing faffle 21 is provided as a behavior detecting means. In the fifth embodiment shown in FIG. 10, the corrugation of the fixing film 21 is directly received by the roller 50. However, when the wave width of the fixing film 21 is small, the reference displacement amount U <b> 1 serving as a behavior determination reference is narrowed. It must be set and a false detection is also assumed.

  Therefore, in this embodiment, the protrusion 58 is provided in the non-sheet passing region 210 on the end portion side of the fixing film 21, and the roller 50 is disposed at a position facing the protrusion 58. The displacement amount of the roller 50 is increased by pushing up the roller 50 when passing between the rollers.

  In this case, the displacement detection means 62 is connected to the control means 100A using a reflective optical sensor. In the control means 100A, a value when the optical detection means 62 detects the roller 50 that has run on the protrusion 58 is set as a reference value R4 as a behavior determination reference, and when the reference value R4 is not detected. The power supply unit 101 may be controlled to stop energization of the heating element 250 based on the determination that the fixing film 21 is not rotating or has a remarkably slow rotation speed.

  With such a configuration, it is possible to detect the rotation and wave state of the fixing film 21 more reliably, and the durability of the fixing film 21 and the apparatus is improved. Further, in this embodiment, since the roller 50 is configured to rotate, the frictional resistance against the rotation of the fixing film 21 can be reduced. The roller 50 applied to the present embodiment may be a form that abuts on the surface of the fixing film 21 instead of a rotating form. In this case, if the frictional resistance with the fixing film 21 is increased, good rotation of the fixing film 21 may be inhibited. Therefore, the contact surface of the roller is curved in a direction in line contact with the outer peripheral surface of the fixing film 21. It is preferably a curved surface. Alternatively, the material itself may be made of a low friction material, or the contact surface may be slippery and coated with a heat resistant material.

(Tenth embodiment)
In this embodiment, as shown in FIG. 19, a pressure detecting means 63 for detecting a contact pressure fluctuation of the roller 50 against the fixing film 21 is used as the behavior detecting means . In the case of this embodiment, the roller 50 is pressed against the outer peripheral surface of the fixing film 21 by the coil spring 59 serving as an elastic member, and a protrusion 58 is provided in the non-sheet passing region 210 on the end side of the fixing film 21. The pressure detector 63 detects the pressure displacement before and after the roller 50 is pushed up.

  A pressure detection unit 63 is connected to the control unit 100A, and a value when the pressure detection unit 63 detects the pressure at which the roller 50 rides on the protrusion 58 is set as a reference pressure R5 as a behavior determination criterion. If the reference pressure R5 is not detected, it is determined that the fixing film 21 is not rotating or its rotational speed is extremely slow, and the power supply unit 101 is controlled to stop energization of the heating element 250.

According to such a configuration, the rotation and wave state of the fixing film 21 can be reliably detected from the pressure displacement of the roller 50, and the durability of the fixing film 21 and the apparatus is improved. Further, in this embodiment, since the roller 50 is configured to rotate, the frictional resistance against the rotation of the fixing film 21 can be reduced. In the present embodiment, the fixing film 21 is provided and the roller 50 is pushed up by the protrusion 58, but the fixing film 21 having no roller 58 may be used. In this case, the shape of the fixing film 21 can be simplified as compared with the case where the protrusions 58 are provided.

(Eleventh embodiment)
In this embodiment, as shown in FIGS. 20 and 21, a rotational load detecting means 65 for detecting a rotational load fluctuation of the roller 50 is used as the behavior detecting means. The rotational load detection means 65 detects the torsion torque of the shaft 55 when the roller 50 rides on the protrusion 58, and is connected to the control means 100A.

  In the control unit 100A, when the reference torsional force R6 that is a behavior determination reference when the roller 50 rotates is set, and the reference torsional force R6 is not detected by the rotational load detection unit 65, the fixing film 21 rotates. The power supply unit 101 is controlled to stop energization of the heating element 250.

  By adopting such a configuration, it is possible to reliably detect the rotation and wave state of the fixing film 21 from the twisting torque of the roller 50, and the durability of the fixing film 21 and the apparatus is improved.

  In the above embodiment, the roller 50 is disposed outside the fixing film 21, but the roller 50 may be disposed inside the fixing film 21 as shown in FIGS. 22 and 23. In this case, the outer peripheral surface of the roller 50 is disposed so as to contact the inner peripheral surface of the fixing film 21.

  As described above, when the roller 50 is disposed inside the fixing film 21, it is possible to detect a behavior change factor that causes deformation or breakage of the fixing film 21 while reducing the influence from devices other than the fixing device 20. And the size of the apparatus can be reduced.

  When the roller 50 is disposed inside the fixing film 21, the shaft 55 may be supported by the stationary holding member 24 disposed inside the fixing film 21. In this case, it is not necessary to newly provide a member for supporting the shaft 55, so the number of parts is reduced. Therefore, a behavior change factor that causes deformation or breakage of the fixing film 21 is caused by a device other than the fixing device 20. It is possible to detect while reducing the influence and improve detection accuracy, and it is possible to promote downsizing and cost reduction of the apparatus.

  In the above embodiment, the present invention is applied to the fixing device 20 using the pressure roller 31 as the pressure member. However, the present invention is also applied to a fixing device using a pressure belt or a pressure pad as the pressure member. can do. In this case, the same effect as that of the first embodiment can be obtained.

  In each of the above embodiments, the control means 100, 100A detects the presence / absence (behavior) of rotation of the fixing film 21 from the output detected by the behavior detecting means, but the fixing film 21 does not have a driving source. The rotation of the roller 31 and the operation failure of the drive motor M1 also affect the rotation. For this reason, from the rotation failure information of the fixing film 21, it may be determined that the pressure roller 31 and the drive motor M <b> 1 associated with the operation are defective, and the power supply to the heating element 250 may be stopped.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. FIG. 2 is a configuration diagram illustrating a configuration of a main part of a fixing device mounted on the image forming apparatus of FIG. 1. FIG. 3 is a perspective view illustrating a configuration of a main part of the fixing device. FIG. 3 is a view of a part of the fixing device of FIG. 2 as viewed from a recording material conveyance direction. It is a figure which shows the state by which a heating means is inserted / removed. (A) is a side view showing the configuration of the main part of the first embodiment of the fixing device of the present invention, (b) is a diagram showing the temperature characteristics by the temperature detection means in the first embodiment. (A) is a side view showing the configuration of the main part of the second embodiment of the fixing device of the present invention, (b) is a diagram showing the temperature characteristics by the temperature detection means in the second embodiment. (A) is a side view showing the configuration of the main part of the third embodiment of the fixing device of the present invention, (b) is a diagram showing the temperature characteristics by the temperature detection means in the third embodiment. (A) is a side view showing the configuration of the main part of the fourth embodiment of the fixing device of the present invention, (b) is a diagram showing the temperature characteristics by the temperature detection means in the fourth embodiment. It is a side view which shows the structure of the principal part of 5th Embodiment of the fixing device of this invention. It is a side view which shows the structure of the principal part of 6th Embodiment of the fixing device of this invention. FIG. 10 is a partial enlarged view showing a configuration of a main part of a sixth embodiment of the fixing device of the present invention. It is a side view which shows the structure of the principal part of 7th Embodiment of the fixing device of this invention. FIG. 10 is a partial enlarged view showing a configuration of a main part of a seventh embodiment of the fixing device of the present invention. It is a side view which shows the structure of the principal part of 8th Embodiment of the fixing device of this invention. FIG. 10 is a partial enlarged view showing a configuration of a main part of an eighth embodiment of a fixing device of the present invention. It is a side view which shows the structure of the principal part of 9th Embodiment of the fixing device of this invention. FIG. 10 is a partial enlarged view showing a configuration of a main part of a ninth embodiment of the fixing device of the present invention. It is a side view which shows the structure of the principal part of 10th Embodiment of the fixing device of this invention. It is a side view which shows the structure of the principal part of 11th Embodiment of the fixing device of this invention. It is a partial enlarged view showing a configuration of a main part of an eleventh embodiment of the fixing device of the present invention. FIG. 3 is a side view illustrating a configuration of a main part of a fixing device in which a rotating member is disposed inside the fixing member. FIG. 24 is a partial enlarged view showing a configuration of a main part of an eleventh embodiment of the fixing device shown in FIG. 23. FIG. 3 is a side view showing a configuration of a main part of a fixing device in which a rotating member is mounted on a holding member and arranged inside the fixing member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Fixing device 21 Fixing member 22 Contact member 23 Reflecting member 24 Holding member 25 Heating means 40 Temperature detection means (behavior detection means)
50 Rotating member 56 Reflecting member 57 Protrusion 60 Optical detecting means (behavior detecting means)
61 Reflection detection means, protrusion detection means (behavior detection means)
62 Displacement detection means (behavior detection means)
63 Pressure detecting means 65 Rotating load detecting means 250 Heating element N Nip portion P Recording material T Toner image

Claims (15)

A fixing member that heats and melts the toner image on the recording material and has flexibility;
A contact member provided inside the fixing member for forming a nip portion by contacting the pressure member via the fixing member;
Heating means disposed on the contact member for heating the contact member;
A reflective member that reflects radiant heat from the heating means and enters the contact member;
Detecting a rotational behavior of the fixing member, and a behavior detecting means disposed substantially on the outer peripheral side of the fixing member and substantially directly above the nip portion ;
A rotating member that contacts the fixing member;
Having a protrusion provided on the rotating member ;
The fixing device according to claim 1, wherein the behavior detection unit is a projection detection unit that detects a projection of the rotating member . A fixing member that heats and melts the toner image on the recording material and has flexibility;
A contact member provided inside the fixing member for forming a nip portion by contacting the pressure member via the fixing member;
Heating means disposed on the contact member for heating the contact member;
A reflective member that reflects radiant heat from the heating means and enters the contact member;
Detecting a rotational behavior of the fixing member, and a behavior detecting means disposed substantially on the outer peripheral side of the fixing member and substantially directly above the nip portion;
A rotating member that contacts the fixing member;
Having a protrusion provided on the rotating member ;
The fixing device according to claim 1, wherein the behavior detecting unit is a displacement detecting unit that detects a displacement of the rotating member in a contact direction with the fixing member . A fixing member that heats and melts the toner image on the recording material and has flexibility;
A contact member provided inside the fixing member for forming a nip portion by contacting the pressure member via the fixing member;
Heating means disposed on the contact member for heating the contact member;
A reflective member that reflects radiant heat from the heating means and enters the contact member;
Detecting a rotational behavior of the fixing member, and a behavior detecting means disposed substantially on the outer peripheral side of the fixing member and substantially directly above the nip portion;
A rotating member that contacts the fixing member;
Having a protrusion provided on the fixing member;
The behavior detecting means is a pressure detecting means for detecting a pressure displacement before and after the rotating member is pushed up by the protrusion as a variation in a contact pressure of the rotating member to the fixing member. apparatus. A fixing member that heats and melts the toner image on the recording material and has flexibility;
A contact member provided inside the fixing member for forming a nip portion by contacting the pressure member via the fixing member;
Heating means disposed on the contact member for heating the contact member;
A reflective member that reflects radiant heat from the heating means and enters the contact member;
Detecting a rotational behavior of the fixing member, and a behavior detecting means disposed substantially on the outer peripheral side of the fixing member and substantially directly above the nip portion;
A rotating member that contacts the fixing member ;
Having a protrusion provided on the fixing member;
The behavior detecting means is a rotational load detecting means for detecting a torsion torque of the shaft of the rotating member when the rotating member rides on the protrusion as a rotational load fluctuation of the rotating member. . A fixing member that heats and melts the toner image on the recording material and has flexibility;
A contact member provided inside the fixing member for forming a nip portion by contacting the pressure member via the fixing member;
Heating means disposed on the contact member for heating the contact member;
A reflective member that reflects radiant heat from the heating means and enters the contact member;
Detecting a rotational behavior of the fixing member, and a behavior detecting means disposed substantially on the outer peripheral side of the fixing member and substantially directly above the nip portion;
A rotating member that contacts the fixing member;
The behavior detecting means detects the behavior of the rotating member,
The fixing device, wherein the rotating member is disposed inside the fixing member. The fixing member is a fixing device according to any one of claims 1 to 5, characterized in that an endless film and thin cylindrical. The fixing member is a fixing device according to any one of claims 1 to 6, characterized in that it has a surface layer of fluorine. The fixing device according to any one of claims 1 to 7, wherein the fixing member and the abutment member is fluorine coated on sliding contact surface. The behavior detecting means, the fixing device according to any one of claims 1 to 8, characterized in that an optical detection means for detecting the rotation of said rotary member. Having a reflecting means for detection provided on the rotating member ;
The behavior detecting means, the fixing device according to any one of claims 1 to 8 characterized in that it is a reflection detecting means for detecting said detection reflection means. Having a protrusion provided on the fixing member;
The fixing device according to claim 2 , wherein the displacement detection unit detects a displacement amount of the rotating member due to the protrusion. The rotating member fixing device according to any one of claims 1 to 11, characterized in that it is disposed outside the fixing member. The rotating member, the fixing device according to any one of claims 1 to 12, characterized in that mounted on the holding member which is fixed inside the fixing member. The heating means has a heating element that generates heat when energized ,
If the detection result by the behavior detecting means is outside the allowable range, the fixing device according to any one of claims 1 to 12, characterized in that stopping the energization of the heating element. The toner image carried on the fed to the recording material as a fixing device for fixing on the recording material by applying heat and pressure, and characterized in that it has a fixing device according to any one of claims 1 to 14 Image forming apparatus .

Images