JPH0519653A - Heating device - Google Patents

Abstract

PURPOSE:To early make the user recognize exchange of a single component such as a film or a pressure roller or necessity of the maintenance, in a film heating system heating device. CONSTITUTION:The heating device is constituted with a fixed heating body, an endless heat resistant film 8 to be moved and driven by being pressed the inner surface with contact with the heating body to face each other, a nip part being formed by inserting the film between the heating body, and a pressure roller 9 moving and driving the film while a heated member carried between the outer surface of the film at the nip part and the roller is pressed by contact with the heating body through the film. The heating device is characterized by that it has the means 15, 16 detecting the moving speed of the film and the means 17, 18 displaying or alarming based on the case the detecting speed is less than a specified value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention introduces a material to be heated, such as a transfer paper, which supports a visible image, on the surface of a heat-resistant film that is pressed against a heating member and driven to move, opposite to the heating member side. The present invention relates to a film heating type heating device which gives heat of a heating body to a material to be heated through the film by closely contacting the film and passing the heating body together with the film.

This device is an electrophotographic copying machine, printer,
An image heat fixing device in an image forming apparatus such as a fax, that is, a recording material (transfer material sheet, transfer material sheet It can be used as an image heating fixing device that fixes a toner image formed on an electrofax sheet, electrostatic recording sheet, printing paper, etc., as a permanently fixed image.

Further, it can be used, for example, in a device for heating a recording material carrying an image to modify the surface properties (such as polishing), a device for presumptive dressing, and the like.

[0004]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 63-313182.
As described in Japanese Patent Publication No. JP-A-2003-242242, a fixedly supported heating element (hereinafter referred to as a heater), a heat-resistant fixing film conveyed (movingly driven) while being pressed against the heater, and a recording material as a heater through the film. Has a pressure member to be closely attached to
An apparatus has been proposed in which the heat of a heater is applied to a recording material via a fixing film to heat and fix an unfixed image formed and carried on the surface of the recording material onto the surface of the recording material.

FIG. 7 shows an outline of an essential part of an example of an image heat fixing device of this type using an endless belt film as a heat resistant fixing film.

Reference numeral 8 is an endless belt-shaped thin film heat-resistant fixing film. The heater 14 is in pressure contact with the pressure roller 9 as a pressure member through the fixing film 8 with a predetermined contact pressure, and forms a fixing nip portion N.

A recording material P as a material to be heated carrying an unfixed toner image Ta conveyed from an image forming portion side (C) (not shown) adheres to the film 8 and passes through the fixing nip portion N together with the film. Then, heat and pressure are applied in the process of passing through the fixing nip portion N. In this process, the toner image is softened, melted, and solidified to form a permanently fixed image Tb.

[0008]

However, such a film heating type apparatus has the following problems.
That is, the relationship of the frictional force between the members 14, 8 and 9 and P is shown in FIG.
As shown in a. Coefficient of friction between the heater 14 and the inner surface of the film 8 μ
1, b. Coefficient of friction between the outer peripheral surface of the fixing film 8 and the recording material P surface μ
2, c. When the friction coefficient between the outer peripheral surface of the film 8 and the pressure roller 9 is μ3, it can be expressed as μ1 <μ2 <μ3.

However, for example, when the image forming apparatus is used for a long period of time, the surface of the pressure roller 9 that rotationally drives the fixing film 8 and the surface layer of the fixing film 8 are worn down, and the surface of the pressure roller 9 and the fixing film are deteriorated. The friction coefficient μ3 between the fixing film 8 and the recording material P also decreases due to the recording material paper dust and the offset toner adhering to the surface layer of the fixing film 8. Therefore, the above-mentioned relationship of the friction coefficient changes with time such as μ2 <μ1 and μ3 <μ1, so that the fixing film 8 stops even though the pressure roller 9 is rotating. Slip phenomenon occurs. When the recording material P is introduced in this state, the recording material P is conveyed, but the fixing film 8 that comes into contact with the unfixed image on the recording material is stopped, so the image on the recording material is rubbed,
A good fixed image cannot be obtained.

The occurrence of slip development of the fixing film 8 as described above is mainly due to the durability life of the single component of the heating device, but for the user, it is appropriate to replace the component in the heating device or clean the heating device. It is difficult to predict the maintenance timing, and since the durability of a single component of the heating device and the maintenance required are considered as one of the causes of the occurrence of the image defect, there is an uneconomical mistaken copy.

It is an object of the present invention to allow a user to promptly recognize the necessity of replacement or maintenance of a single component of a heating device.

[0012]

The present invention is a heating device characterized by the following constitutions.

(1) A nip portion is formed by sandwiching the film between a fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and driven to move, and the heating body. A heating device that is conveyed between the film outer surface in the nip portion and a pressure roller that drives and drives the film while pressing the heated material through the film to the heating body, The heating device, which has means for detecting the moving speed of the film and means for displaying or warning if the detected speed is less than a predetermined value.

(2) The heating device according to (1), wherein the start time of energization of the heating member can be set by detecting the moving speed of the fixing film after the supply of the material to be heated by the detecting means.

(3) The heating device according to (1) or (2), wherein the film moving speed detecting means is a photo sensor arranged at least at one end in the width direction of the film.

[0016]

In other words, a means for detecting the moving speed of the heat-resistant film based on the driving of the pressure roller of the heating device is provided to detect the moving speed of the film, and the detected moving speed is below a predetermined value including stop. If it is in the state, it can be judged that the film slip phenomenon due to the durable life of the single component of the heating device has occurred. Therefore, when the detected moving speed of the film is detected to be below a specified value, including stop, the display or warning means is activated to reach the time when it is necessary to replace or perform maintenance on a single part of the heating device. This can be distinguished from other abnormalities in the apparatus to prompt the user to recognize it earlier, and it is possible to eliminate the uneconomical situation of outputting a copy with defective fixing thereafter.

Further, by knowing the transfer time of the recording material from the paper feeding to the heating device by the above-mentioned detecting means, and appropriately controlling the start of energization of the heating device, the energization time for preheating the heating device is shortened. To reduce the power consumption.

[0018]

【Example】

<Example 1> (FIGS. 1 to 4) (1) Example of image forming apparatus FIG. 3 is a schematic configuration diagram of an example of a laser beam printer using a heating device according to the present invention as a fixing device.

Reference numeral 1 denotes an electrophotographic photosensitive drum (hereinafter abbreviated as drum) which is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). The drum 1 is uniformly charged to a predetermined positive or negative potential by the primary charger 2 in the course of rotation, and then is scanned and written with the target image information by the laser scanning exposure L by the laser scanner 3. As a result, an electrostatic latent image corresponding to the target image information is formed on the drum 1.

The surface of the drum 1 on which the latent image is formed is visualized as a toner image by being supplied with the toner T by the developing device 4.

Then, the toner image passes through the position of the transfer roller 5 and the transfer roller 5 and the drum 1.
In the meantime, the recording material P is sequentially transferred onto the surface of the recording material P sent from the paper feeding unit including the paper feeding cassette 20, the paper feeding roller 21, the separation claw or separation pad 22, the registration roller pair 23, and the like. The transfer from the drum 1 to the surface of the recording material P is performed by the transfer roller 5 charging the reverse side of the charging material to the back side of the recording material P surface.

The recording material P that has received the transfer of the toner image is neutralized by the static elimination needle 6 to which a voltage having a polarity opposite to that of the transfer roller 5 is applied, separated from the drum 1, and conveyed to the fixing device 7 to fix the toner image. The sheet is received and discharged by the discharge roller 24 to the outside of the machine.

After the recording material is separated, the surface of the drum 1 is cleaned by a cleaning device 25 to remove residual adhered substances such as transfer residual toner, and is repeatedly used for image formation.

(2) Fixing Device 7 In the fixing device 7, the unfixed toner image on the surface of the recording material P is heated and melted and fixed on the recording material P surface as a permanently fixed image.

FIG. 3 shows a cross section of the fixing device 7. FIG. 1 shows a vertical sectional front view of the fixing device 7.

The fixing film 8 has heat resistance, toner releasability,
It is a tough single-layer fixing film or a composite layer film that has been subjected to a desired surface treatment or lamination treatment. For example, heat-treated polyester of about 50 μm (PET)
And a polyimide (P1) single layer film, or a composite layer film obtained by further treating the film surface with a tetrafluoride ethylene (PTFE).

In the fixing device 7 of this embodiment, the fixing film 8 has an endless cylindrical shape, and no tension is applied in the circumferential direction except for the nip portion N, and the fixing film 8 is rotated only by the frictional force with the pressure roller 9. It is configured to run.

The heater 14 and the pressure roller 9 that are in contact with the film guide member 10 that guides the inner surface of the fixing film 8 over the entire lengthwise direction are in predetermined contact with the fixing spring 8 by the pressure springs 11a and 11b. They are pressed against each other with pressure (for example, A4 width and total pressure of 3 to 6 kg).

TaSi formed on the surface of the heater 14 by vapor deposition, sputtering, CVD, screen printing, etc.
There is a linear or strip-shaped thin-film heat generating resistance portion of O ₂ , silver palladium, Ta ₂ N, RuO ₂ , nichrome, or the like.

By controlling the end portion of the fixing film 8 by the flange 13 attached to the film guide member 10 when assembling the apparatus, the deviation of the fixing film 8 generated when the fixing device 7 is driven is controlled.

The recording material P on which the unfixed toner image is transferred is conveyed to the fixing nip portion N together with the fixing film 8 by the surface frictional force of the pressure roller 9 rotated by the driving gear 12, and at least in the fixing nip portion N. Then, the pressure spring 11
The recording material P is fed in the advancing direction of the fixing film 8 and the pressure roller 9 at the same speed as the fixing film 8 and the pressure roller 9 without slipping due to the contact pressure by the a and 11b.

The passing process in the fixing nip portion N is a heating and pressurizing process, the heat of the heater 14 is transmitted to the recording material P through the fixing film 8, and the unfixed toner on the recording material P is melted and softened. Pressurized.

After passing through the fixing nip portion N, the fixing film 8 and the recording material P are conveyed while being in close contact with each other due to the adhesive force of the melted and softened toner. The heat of the melted and softened toner is dissipated as a cooling step in this conveying process, the toner is cooled and solidified, and a permanent fixed image is formed on the recording material P.

After the cooling step, the fixing film 8 and the recording material P are easily separated by cooling and solidifying the toner, and the recording material P is discharged from the fixing device 7.

(3) Film moving speed detecting means FIG. 2 is a perspective view of the film moving speed detecting means. That is, in this embodiment, the opaque release layer surface treatment is regularly applied 8b in the circumferential direction of the fixing film to the outside of the paper passing area a of at least one widthwise end portion 8a of the fixing film 8,
In the non-applied portion 8b, the transmissive photosensor 15 is configured to repeat turning on and off at regular intervals as the fixing film 8 rotates.

The on / off signal of the photo sensor 15 is input to the speed detecting circuit 16 to calculate the moving speed of the film from the on / off cycle, and is compared with a predetermined reference speed value.

The moving speed of the film is detected during the rotation of the image forming apparatus before feeding, and when the detected speed is less than a predetermined reference speed value (including the stopped state), the durable life of the single component of the heating device The circuit 16 judges that the film slip phenomenon has occurred and the display or warning means 17 is activated accordingly. At the same time, the circuit 18 for stopping the main body of the image forming apparatus is operated. As a result, the user can recognize that it is time to replace the single component of the heating device or the time when maintenance is necessary, by distinguishing it from other abnormalities in the device and deal with it early.

Before the endurance life of the pressure roller 9 and the fixing film 8, that is, in the fixing nip N, there is no slip phenomenon between the fixing film 8, the pressure roller 9 and the recording material P, and the moving speed of the film is in a normal state. If it is determined that the recording medium has been detected, the detection means detects the number of revolutions of the fixing film 8 that has been rotating since the recording material is supplied to the image forming apparatus, and immediately before the recording material is conveyed to the fixing device 7. Heater 14
It was possible to start energizing the. The reason why the fixing device 7 can sufficiently reach the toner melting temperature by starting energization immediately before the recording material is conveyed is due to the configuration and low heat capacity of the fixing device. FIG. 4 shows the correlation between the temperature and time of the fixing device.

The present embodiment has the following effects.

(A) By notifying the user of the endurance life of the fixing device component, it is possible to discriminate from other abnormalities in the image forming apparatus. In addition, it is possible to prevent improper fixing by detecting speed irregularities including stop of the fixing film at the time of rotation before feeding, and notify the user of early replacement of parts and maintenance.

(B) The above-mentioned pattern 8b with and without a surface layer provided outside the sheet passing area where breakage of the end portion of the fixing film caused by rubbing between the edge portion of the fixing film and the deviation regulating member 13 of the rotating fixing film In the case of reaching the upper side, since the photo sensor 15 is turned on at the break portion, the on / off cycle of the photo sensor changes, and the abnormality of the fixing film 8 is detected, so that the end portion of the fixing film 8 is broken. It is also possible to prevent inadequate fixing that occurs in the paper passing area b.

(C) It has become possible to detect the time from the feeding of the recording material P to immediately before the conveyance of the fixing device, depending on the number of rotations of the fixing film 8. Therefore, if the energization to the fixing device 7 is started immediately before the recording material is conveyed, it is not necessary to energize the fixing device during the conveyance from the recording material feeding to the fixing device 7, and the power saving effect of the image forming apparatus main body can be obtained. is there.

<Embodiment 2> (FIGS. 5 and 6) In the present embodiment as well, as in Embodiment 1, a means 19A for detecting a slip of the fixing film 8 at least at one side end of the fixing film 8 in the width direction, 19a is provided. The fixing film 8 receives a moving force toward the direction A in the figure by forming the film guide member 10 for guiding the inner peripheral surface thereof in a unidirectional taper shape with respect to the pressure roller 9.
The deviation of the fixing film 8 is a rib 19 made of a heat-resistant resin provided at one end of the fixing film 8 (on the side opposite to the deviation direction A).
It is regulated by the deviation regulating member 19A. 10A
Is a film tension roller.

FIG. 6 shows the relationship between the fixing film 8, the ribs 19 and the deviation regulating member 19A. Deviation control member 19A
Is a photo sensor, which detects the projections 19a regularly provided in the circumferential direction of the rib 19 at a constant cycle according to the rotation speed of the fixing film 8. Therefore, as in the first embodiment, the fixing film 8 is stopped. The improper moving speed can be detected by the change in the detection cycle, and the conveyance timing of the recording material to the fixing device 7 can be known by the number of rotations of the fixing film 8 after the recording material is fed. The convex portion 19a is an example of detection means by the photosensor 19A, and naturally, other means for turning the photosensor on and off may be used.

Therefore, the user is informed of the replacement and maintenance of the fixing device component due to its durable life, the abnormality in the image forming apparatus is discriminated, and the energization of the fixing device is started in synchronization with the conveyance of the recording material. It has the same effect as in Example 1.

In addition, in the present structure in which the deviation regulating member 19A is integrated with the photo sensor, the rib 19 is always in contact with the photo sensor 19A, and the photo sensor 19A is formed by using a part of the rigid rib 19. On,
By turning it off, the rotation speed of the fixing film 8 can be detected more accurately. Further, by integrating the regulation member 19A and the photo sensor, there is an effect of cost reduction.

[0047]

According to the present invention, in a heating device for rotating the film while the inner surface of the heat-resistant film is pressed against a heating body, at least one end portion in the width direction of the rotating film is heated, for example. By providing a means for detecting irregularities in the moving speed of the film caused by the durable life of the pressure roller, film, etc., the heating device can be used as an image fixing device by promptly notifying the user of replacement and maintenance of the film, pressure roller, etc. If so, it is possible to prevent fixing failure in advance and easily distinguish it from other abnormalities in the image forming apparatus. Further, it becomes possible to start the energization of the fixing device by knowing the conveying time of the recording material from the paper feeding to the fixing device by the detecting means, and the power consumption can be saved.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a fixing device according to a first embodiment.

FIG. 2 is a perspective view of a film moving speed detecting means portion.

FIG. 3 is a schematic configuration diagram of an example of a laser beam printer using the fixing device.

[Fig. 4] Relationship between heater temperature and time

FIG. 5 is a perspective view of a fixing device according to a second embodiment.

FIG. 6 is a side view of the main part.

FIG. 7 is an explanatory view of a film heating type heating device.

FIG. 8 Diagram of friction coefficient relationship between main members

[Explanation of symbols]

1: Electrophotographic photoreceptor 2: Primary charger 3: Laser scanner 4: Developing device 5: Transfer roller 6: Static elimination needle 7: Fixing device 8: Fixing film 9: Pressure roller 10: Guide 11: Pressure spring 12: Drive gear 13: Flange 14: Heater 15: Photo sensor 19: Rib 19A: Leaning regulation member and photo sensor

Claims (3)

[Claims] 1. A nip portion is formed by sandwiching the film between a fixed heating body, an endless heat-resistant film whose inner surface is pressed against the heating body and driven to move, and the heating body. A heating device having a pressure roller that drives and drives the film while pressing the heated material conveyed between the film outer surface in the nip portion and the heating body through the film, A heating device comprising means for detecting a moving speed and means for displaying or warning if the detected speed is less than a predetermined value. 2. The heating device according to claim 1, wherein the start time of energization of the heating member can be set by detecting the moving speed of the fixing film after the supply of the material to be heated by the detecting means. 3. The heating device according to claim 1 or 2, wherein the film moving speed detecting means is a photosensor arranged at least at one end in the width direction of the film.