JPH1165350A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording device capable of preventing a break the dirt of a temp. detecting means during the time of processing a jamming, or the damage or the like of a fixing roller. SOLUTION: This device is constituted by allowing both end of the fixing roller 1 and the pressure roller 2 to be turnably held by a slot 6a of the roller holding member 6, allowing the pressure roller 2 to be brought into press contact with the fixing roller 1 by pressurizing the pressure roller 2 toward the fixing roller 1 by a pressure arm 4, and allowing a thermistor 13 to be brought into contact with a surface of the fixing roller 1 across the thermistor spring 13a. Moreover, on the above of a receiving section 4a of an end part on the pressure arm 4, a pressurization releasing means 3 provided with a cam 3a having such a shape that it is not brought into contact with the receiving section 4a in a pressurizing state of the pressure arm 4, and in the pressure released state of the pressure arm 4, a pressure releasing state is held by depressing the receiving section 4a is arranged and when the pressurizing state of the pressure arm 4 is released by making the cam 3a to be rotated, the end part of the pressure arm 4 is depressed by the cam 3a and the pressure roller 2 falls along the slot 6a of the holding member by gravity, while the fixing roller 1 and the thermistor spring 13 are separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image recording apparatus having a roller fixing device such as a printer and a copying machine.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus, an image carrier for forming an electrostatic latent image on the surface thereof, a pre-exposure means for removing charges on the surface of the image carrier, and a surface of the image carrier having a desired electric potential. Primary charging means for charging the image carrier, exposing means for exposing the charged image carrier to form an electrostatic latent image, and developing for developing the electrostatic latent image on the image carrier with a developer to make it a visible image Device, a transfer device for transferring the toner image on the image carrier developed by the developing device to a recording material, a roller fixing device for fusing and fixing the toner image transferred to the recording material by a heated and pressed fixing roller, and the like. It is placed in a predetermined position, and charged, exposed, developed, transferred,
An image is recorded on a recording material by each image forming process such as fixing. As the recording material, recording paper, OHP paper, or the like is used.

The roller fixing device includes a fixing roller which is heated by being provided with a heater therein, and which is rotatably held by a housing or the like of the roller fixing device; A pressure roller which is pressed in the direction of the fixing roller by a pressure means having a nip portion where a recording material onto which an unfixed toner image has been transferred is a pressure contact portion between the fixing roller and the pressure roller. , The toner on the recording material is fused and fixed by the heat of the fixing roller heated by the heater and the pressing force between the fixing roller and the pressure roller, so that an image is recorded on the recording material. ing.

Further, the fixing roller of the roller fixing device includes:
A temperature sensor as a temperature detecting means such as a thermistor is brought into contact with the pressure of a spring member or the like, and the temperature is adjusted by a signal from the sensor. This temperature sensor always keeps contact with the fixing roller even during normal printing.

In the roller fixing device, the recording material passes while the fixing roller and the pressure roller are pressed against each other. Therefore, the recording material is not discharged normally from both rollers but is caught between the two rollers. In some cases, a jam occurs in which the conveyance of the paper is stopped. When the jam occurs, it is necessary to perform a jam process for removing the stopped recording material in order to restart the image recording process. In the normal jam processing, the recording material sandwiched between the fixing roller and the pressure roller is pulled out in a state where the fixing roller and the pressure roller are in contact with each other. Further, a pressure releasing means for releasing the pressurized state of the pressure means of the pressure roller which is pressed against the fixing roller is provided, and the pressure contact state between the fixing roller and the pressure roller by the pressure releasing means at the time of jam processing. Is released, and the recording material is pulled out of the roller fixing device in a state where no pressure is applied.

In a normal state, the fixing roller and the pressure roller are pressed against each other at a predetermined pressure, and the pressure due to the pressure may deform the pressure roller and the like. When the device is not used for a long period of time, such as when shipping an image recording device, or when replacing a roller fixing device, for example, a resin spacer may be provided between the shafts of both rollers. The roller is kept in a state in which it does not come into pressure contact with the roller, or the pressing means is kept in a pressure released state by the pressure releasing means.

[0007]

However, in the conventional roller fixing device in which the fixing roller and the temperature sensor always keep in contact with each other, the sheet remaining outside the fixing device due to an operation such as pulling out the sheet remaining in the fixing device due to a jam or the like. When the paper is discharged, problems such as damage or deformation of the temperature sensor itself due to the deformed paper have occurred.

In the case where image recording is continuously performed, the surface temperature of the fixing roller may be lower than the set temperature. In the fixing roller having the temperature lower than the set temperature, the toner is fixed without being dissolved. The sensor is contaminated by being attached to the surface of the roller and scraped off by the sensor that comes into contact with the rotation of the fixing roller during jam processing. further,
The fixing roller has been scratched, scraped, etc. by the toner adhered due to the sensor contamination.

Further, when a spacer is provided in order to prevent deformation of the roller, the number of parts increases, which is troublesome and costly. In addition, if the spacer is forgotten to be removed at the time of use, there is a problem that the apparatus may be damaged. there were.
Further, when the product is shipped in a state where the pressure is released, it is necessary to surely bring both rollers into a pressed state before use.

Accordingly, the present invention provides a method for releasing the pressing state of the pressing unit by releasing the contact state between the fixing roller and the temperature detecting unit and separating the fixing roller from the temperature detecting unit. It is an object of the present invention to provide an image recording apparatus that can prevent damage and dirt on a detection unit, damage on a fixing roller, and the like. In addition, by synchronizing pressurization or depressurization of the fixing roller with detachment and attachment of the roller fixing device from the image recording apparatus main body, the workability of the device management during jam clearance and moving storage is improved, and the temperature detection member is removed. It is an object of the present invention to provide an image recording device capable of preventing breakage and the like. Still another object of the present invention is to provide an image recording apparatus which can easily fix a thick recording material by providing a depressurized state in the middle of a pressurized state and a depressurized state of the pressurizing means. .

[0011]

According to a first aspect of the present invention, an object of the present invention is to provide a fixing roller heated by a heating unit and pressed by a pressing unit, and abutting on the fixing roller. A temperature detecting means for detecting the surface temperature of the fixing roller, and a pressure releasing means capable of releasing the pressurized state of the pressurizing means and maintaining the depressurized state, wherein the pressurized and heated fixing roller In an image recording apparatus provided with a roller fixing device for fixing an unfixed image on a recording material by pressing force and heat, the fixing roller is brought into contact with the temperature detecting means when the fixing roller is pressurized. A roller holding member which can guide the movement of the fixing roller in a direction in which the contact state between the fixing roller and the temperature detecting means is released when the pressure of the fixing roller is released by the pressure releasing means. In synchronization with the pressure releasing means it is achieved by spacing of Seraru a fixing roller temperature sensing means.

Further, according to a second aspect of the present invention, the above object is achieved in that the pressure releasing means is locked to the main body of the image recording apparatus when the pressing means is in the pressurized state, and the image recording of the roller fixing apparatus is performed. A lock member is provided which can hold the state of attachment to the apparatus and release the lock from the image recording apparatus main body in response to the release of the pressure of the pressure release means and release the state of attachment of the roller fixing device to the image recording apparatus. This is achieved by:

According to a third aspect of the present invention, there is provided a roller fixing device, wherein the roller fixing device is provided with a pressure contact member for pressing the temperature detecting means against the surface of the fixing roller. This is achieved by making the amount of movement of the temperature detecting means by the pressing force smaller than the amount of movement of the fixing roller in the pressure releasing state of the pressing means.

According to a fourth aspect of the present invention, there is provided a roller fixing device, wherein the roller fixing device is provided with a restricting portion for restricting the amount of movement of the temperature detecting means in the pressure contact direction by the pressure contact member. The part is achieved by enabling the amount of movement of the temperature detecting means due to the pressure contact of the pressure contact member to be smaller than the amount of movement of the fixing roller when the pressing means is in the pressure released state.

Further, according to the fifth aspect of the present invention, the above object is achieved by that the pressurizing means can maintain the pressurizing means in a depressurized state in the middle between the pressurized state and the depressurized state. A pressure reducing section is provided, and the pressing member of the temperature detecting means is configured such that the amount of movement of the temperature detecting means due to the pressing of the pressing member is smaller than the amount of movement of the fixing roller when the pressing means is in the depressurized state, and This is achieved by allowing the fixing roller and the temperature detecting unit to contact each other in the pressure state and the pressure reduction state.

That is, according to the first aspect of the present invention, by pressing the fixing roller by the pressing means,
With the fixing roller held by the roller holding member, the fixing roller and the temperature detection unit are brought into contact with each other, and the pressurized state of the pressurizing unit is released by the pressurizing release unit to maintain the depressurized state. Since the fixing roller moves in a direction away from the temperature detecting means along the roller holding member, the jam processing is performed in a state where the fixing roller and the temperature detecting means are separated from each other. Roller damage and the like are prevented.

Further, according to the second aspect of the present invention, the roller fixing device is locked to the main body of the image recording apparatus by pressing the fixing roller by the lock member provided in the pressure releasing means. The roller fixing device can be detached from the image recording apparatus main body in response to the pressure release of the pressure release unit, and the fixing roller and the temperature detecting unit are separated from each other, so that the workability of the device management during the jam processing and the moving storage is improved. In addition, the temperature detection member is prevented from being damaged due to the jam clearance.

According to the third aspect of the present invention, when the fixing roller is pressed by the pressing member, the fixing roller and the temperature detecting means are reliably brought into contact with each other. The distance between the fixing roller and the temperature detecting means is reliably ensured.

Further, according to the fourth aspect of the present invention, the amount of movement of the temperature detecting means by the pressing of the pressing member is regulated by the regulating portion, so that the fixing roller can be more reliably moved when the pressure of the fixing roller is released. The distance to the temperature detecting means is ensured.

According to the fifth aspect of the present invention, a recording material having a normal thickness can be fixed with a simple structure and operation by a pressure reducing unit provided in the pressure releasing means. And fixing are switched.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. The image recording apparatus 11 for fixing an unfixed image on a recording paper is not shown in the image recording apparatus 11, but an image carrier for forming an electrostatic latent image on the surface and a charge on the surface of the image carrier are removed. Pre-exposure means, primary charging means for charging the surface of the image carrier to a desired potential, exposure means for exposing the charged image carrier to form an electrostatic latent image, and electrostatic latent image on the image carrier. A developing device that develops an image with a developer to make it a visible image, a transfer device that transfers a toner image on the image carrier developed by the developing device to a recording material, and the like are provided. Further, a fixing unit 10 which is a roller fixing device for fusing and fixing the toner image transferred to the recording material by a fixing roller heated and pressed is provided in the image recording device 11.
Is detachably disposed at a predetermined position, and a desired image can be obtained by appropriately executing each process of image formation by each member. Note that recording paper, OHP paper, or the like is used as the recording material.

As shown in FIG. 2, a fixing unit 10 for fixing a sheet (not shown), which is placed in a recording apparatus main body 11 and carries an unfixed image, by heat and pressure, comprises:
A fixing roller 1 having a heater 17 inside for directly applying heat and pressure to the sheet by directly contacting the sheet, and being pressed against the surface of the fixing roller 1 to transmit the pressing force, and to apply heat and pressure to the sheet. A pressure roller 2 for applying pressure is provided. Both ends of the fixing roller 1 and the pressing roller 2 are elongated holes along a pressing direction by pressing means described later, a roller holding unit 6 provided near both ends of both rollers of the housing of the fixing unit 10. The fixing roller 1 and the pressure roller 2 are slidably held along the longitudinal direction of the long hole 6a. Further, a driving gear 18 for transmitting a driving force from a driving source (not shown) in the recording apparatus main body 11 to the fixing roller 1 is provided, and the driving force from the driving source is transmitted to the fixing roller 1 via the driving gear 18. 1 and the pressure roller 2, so that both rollers rotate in a predetermined direction.

As a pressing means for applying pressure to both rollers, base ends provided at both ends in the longitudinal direction of the fixing unit 10 are rotatably supported by fulcrums 5 and end portions of the pressing roller 2. Pressurizing arms 4 for rotatably holding the
And one end is locked to a receiving portion 4a provided at the end of the pressure arm 4 and the other end is locked to the housing of the fixing unit 10 so that the end of the pressure arm 4 is turned clockwise. The pressure roller 2 held in the middle of the pressure arm 4 is fixed to the fixing roller 1 by pressing the pressure arm 4 in the clockwise direction by the elastic force of the spring 7. The pressure roller 2 can be pressed against the fixing roller 1 by pressing in the direction. At this time, since the fixing roller 1 is held in a state where both ends of the fixing roller 1 abut against the end of the elongated hole 6 a of the roller holding member 6 on the opposite side to the pressing arm 4, the pressing arm 4
Is transmitted to the fixing roller 1 via the pressure roller 2 so that the two rollers are pressed against each other.

Above the receiving portions 4a of the pressure arm 4 provided at both ends in the longitudinal direction of the fixing unit 10, a pressure capable of releasing the pressure state of the pressure arm 4 and maintaining the pressure released state is provided. Release means 3 is provided, and the pressure release means 3
The cam 3a whose eccentric position is supported by the shaft 9 and the cam 3a
And a drive lever 3b for rotating the.

The cam 3a has three stepped portions on the peripheral portion on the side facing the shaft 9 in which the distance from the shaft 9 decreases in order. As shown in FIG. 1, of the three steps provided on the cam 3a, the step having the shortest distance from the shaft 9 grips the drive lever 3b to a position facing the receiving part 4a of the pressing arm 4. , A gap is formed between the receiving portion 4a of the pressing arm 4 pushed up by the spring 7 and the cam 3a, and the shaft 9 of the three steps of the cam 3a is formed. The pressing roller 2 and the fixing roller 1 can be pressurized in a state where the stepped portion having the shortest distance from the pressing arm 4 is located at a position facing the receiving portion 4 a of the pressing arm 4.

As shown in FIGS. 3 and 4, of the three steps of the cam 3a, the step having the longest distance from the shaft 9 comes in contact with the receiving part 4a of the pressing arm 4. By rotating the cam 3a so as to come to the position, the step portion having the longest distance from the shaft 9 pushes down the receiving portion 4a of the pressing arm 4, and the pressing state of the pressing arm 4 can be released. At the same time, the stepped portion is held by the receiving portion 4a of the pressure arm 4 so that the pressure release state can be held. When the pressure contact state of the pressure roller 2 is released, the fixing roller 1 is released.
The fixing roller 1 slides downward along the long hole 6a of the roller holding member 6 by its own weight to move the fixing roller 1.

As shown in FIGS. 5 and 6, the cam 3a
Of the three steps, the step having an intermediate distance from the shaft 9 constitutes a decompression section that can hold the pressurizing means in a depressurized state in the middle between the pressurized state and the depressurized state. By rotating the cam 3a so that the step portion having an intermediate distance from the shaft 9 comes into contact with the receiving portion 4a of the pressing arm 4, the step portion having an intermediate distance from the shaft 9 is added. Pressure arm 4
By pressing down the receiving portion 4a, the pressure by the pressure arm 4 can be reduced to a depressurized state which is a middle state between the pressurized state and the pressure released state, and the stepped portion is received by the pressure arm 4 Part 4
The pressure-reduced state can be maintained by holding the pressure at a. The pressure arm 4 in the depressurized state reduces the pressure contact force between the fixing roller 1 and the pressure roller 2, so that thick paper or the like can be passed between the two rollers.

The shaft 9 supporting the cam 3a has a cam 3
and a lock member 8 for rotating the fixing unit 10 to the apparatus main body 11 and rotating the driving lever 3b after the fixing unit 10 is installed in the image recording apparatus 11 main body. The fixing unit 10 is fixed to the main body of the image recording apparatus 11 by engaging the end of the lock member 8 with the notch 12 provided at a predetermined position of the main body of the image recording apparatus 11 by grasping and rotating in a predetermined direction. I can do it.

As shown in FIG. 1, the lock member 8 is gripped by the drive lever 3b and rotated in a predetermined direction to lock the lock lever 8b.
Of the cam 3 by engaging the end of the cam 3 with the notch 12.
The stepped portion a of which the distance from the shaft 9 is the shortest is opposed to the receiving portion 4a of the pressure arm 4, and the engagement between the end of the lock member 8 and the notch portion 12 is released. The stepped portion of the pressing unit 3a, which is the longest distance from the shaft 9, pushes down the receiving unit 4a of the pressing arm 4 so that the pressing state of the pressing arm 4 can be released. Pressing and releasing of the pressure of the fixing roller 1 and the pressure roller 2 are performed in accordance with the attachment and detachment from the apparatus 11 main body. As shown in FIG. 5, when the cam 3a is rotated to reduce the pressure, the end of the lock member 8 is engaged with the notch 12 so that the cam 3a and the lock member 8 are engaged.
Is adjusted.

A thermistor 13 is provided on the surface of the fixing roller 1 as a temperature detecting means which is in contact with the surface of the fixing roller 1 and detects the surface temperature. The thermistor 13 detects the surface temperature of the fixing roller 1. Thus, the temperature of the heater 17 can be controlled from the printing apparatus main body side.

The thermistor 13 is provided on a thermistor spring 13a using a leaf spring, for example, which is disposed at an appropriate position of the fixing unit 10. It is supposed to be. The thermistor is
It is locked to the fixing unit via a thermistor spring and is brought into contact with the fixing roller at a predetermined pressure.
However, the present invention is not limited to this, and the thermistor may be fixed at a position where it comes into contact with the surface of the fixing roller in the pressurized state and depressurized state of the pressurizing arm. The thermistor spring 13a is not limited to a leaf spring, but may be an elastic member such as a coil spring.

Further, the fixing unit 10 is provided with a thermistor stopper 14 which is a regulating portion for regulating the amount of movement of the thermistor 13 by the thermistor spring 13a.
The position of the thermistor stopper 14 is adjusted so that the fixing roller 1 and the thermistor 13 can be separated by a distance D shown in FIG. In the reduced pressure state by 3a, the adjustment is performed so that the fixing roller 1 and the thermistor 13 are in contact with each other. In this case, the thermistor stopper may not be provided. In such a case, the amount of movement of the thermistor due to the spring force of the thermistor spring is smaller than the amount of movement of the roller in the pressure release state of the pressing arm. Adjust the spring force of.

When the fixing unit 10 having the above-mentioned structure is mounted on the main body of the image recording apparatus 11, a driving force from a driving source (not shown) of the main body 11 is transmitted through a driving gear 18. Accordingly, the fixing roller 1 heated by the heater 17 and the pressure roller 2 to which the heat from the heated fixing roller 1 is transmitted rotate. The pressure roller may be heated by providing a heater to the pressure roller.

At this time, the pressure generated by the spring 7 is applied to the receiving portion 4a of the pressing arm 4 swinging about the fulcrum 5 and transmitted as a pressing force for pressing the pressing roller 2 against the fixing roller 1. The paper (not shown) carrying the unfixed image passes between the pressure roller and the fixing roller 1 and the pressure roller 2 to which the heat is applied and which rotates as described above. As a result, the unfixed image is fixed on the sheet, and the fixing process ends.

Next, when the paper needs to be discharged from the fixing unit 10 due to the occurrence of a jam, or when the fixing unit 10 is taken out of the apparatus main body 11 for some reason, or when the apparatus main body 11 is not used for a long time. The levers 3c on both sides of the fixing unit 10 are arranged around a shaft 9 that supports the cam 3a and the lock member 8.
By pushing up each of them, the end of the lock member 8 is released from the notch portion 12, and the fixing unit 10 can be pulled out from the main body of the image recording apparatus 11 to the near side in FIG.

The cam 3a rotated in synchronization with the rotation of the lock member 8 compresses the receiving portion 4a of the pressing arm 4 and the contact spring 7 to push down and fix the pressing arm 4.
As a result, as shown in FIG. 3, the pressing roller 2 released from the pressing state by the pressing arm 4 is pushed down, and the fixing roller 1 is also lowered by its own weight. At this time,
The thermistor 13 fixed to the thermistor spring 13a provided in the fixing unit 10 includes a thermistor spring 13a.
a, the end of the thermistor spring 13a and the thermistor stopper 14 come into contact with each other.
3 and the fixing roller 1 are maintained by the distance D. By performing the jam processing in this state, the surface of the fixing roller 1 is not damaged by the thermistor 13 and
Since the thermistor 13 is separated from the work position of the jam processing, the jam processing with little damage to the thermistor 13 can be performed.

When the use is restarted after the jam has been cleared, the pressure release state by the cam 3a is released by rotating the drive lever 3b in the direction in which the pressing down of the pressure arm 4 by the cam 3a is released. The pressure arm 4 is pushed up by the restoring force, and the pressure roller 2 is fixed to the fixing roller 1.
And a state in which fixation is possible.

As described above, the fixing unit 10 can be attached to and detached from the image recording apparatus 11 only by operating the drive lever 3b, and the pressure between the fixing roller 1 and the pressure roller 2 is released or released. Contact and separation between the fixing roller 1 and the thermistor 13 can be simultaneously performed.

Further, the fixing unit 10 is shown in FIGS.
As shown in FIG. 3, a depressurized state that is intermediate between the depressurized state shown in FIG. 3 and the pressurized state shown in FIG. 2 can be set. Can be taken. The cam 3a pushes down the receiving portion 4a of the pressing arm 4 by rotating the lever 3c about the shaft 9. At this time, a step is set in the peripheral portion of the cam 3a so as to press down the pressing arm 4 to an appropriate pressure in advance between the time when the cam 3a is pressed and the time when the pressure is released. Further, in this state, the lock member 8 is not released from the notch portion 12, and the pressure is reduced while the fixing unit 10 is fixed to the main body 11.

Further, in this state, as shown in FIG. 6, only the pressure of the pressure roller 2 applied to the fixing roller 1 is reduced, and the fixing roller 1 does not move when the pressure is released. The temperature of the fixing roller 1 remains in contact with the surface of the fixing roller 1 by the action of the spring 13a. For this reason lever 3
By rotating c to this position, the paper can be passed at an appropriate pressure with respect to the thick paper.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the cam for changing the pressurized state of the pressurizing arm is provided in the pressurizing releasing means in the first embodiment, but instead, the pressing down of the pressurizing arm by the pressure releasing lever is performed. It is something to do. Except for the configuration of the pressure release means, the configuration and operation of the pressure arm and both rollers are the same, and the same reference numerals are given to the common parts with the first embodiment.

A fixing unit 10 'having a pressure release lever for releasing the pressurized state of the pressurizing arm serving as a pressurizing means is detachably provided in the main body of the image recording apparatus. The fixing unit 10 ′ is provided with a fixing roller 1 having a heating heater 17 therein, and a pressure roller 2 pressed against the surface of the fixing roller 1. Both ends of the fixing roller 1 and the pressure roller 2 are rotatably held in the elongated holes 6a of the roller holding unit 6 in the same manner as in the first embodiment. It can slide along the longitudinal direction of the long hole 6a. Further, a driving gear 18 for transmitting a driving force from a driving source (not shown) in the recording apparatus main body 11 to the fixing roller 1 is provided, and the driving force from the driving source is transmitted to the fixing roller 1 via the driving gear 18. 1 and pressure roller 2
, Both rollers rotate in a predetermined direction.

As a pressing means for applying pressure to both rollers,
Two pressure arms 4 rotatably supported by fulcrums 5 provided at both ends in the longitudinal direction of the fixing unit 10 and rotatably holding the end of the pressure roller 2; Two springs 7, one end of which is locked to a receiving portion 4a provided at the end of the pressure arm 4 and presses the end of the pressure arm 4 in the clockwise direction, are provided by the elastic force of the spring 7. By pressing the pressing roller 4 in the clockwise direction, the pressing roller 2 held in the middle of the pressing arm 4 is pressed in the direction of the fixing roller 1 so that the pressing roller 2 can be pressed against the fixing roller 1. I have.

Above the receiving portions 4a of the pressure arm 4 provided at both ends in the longitudinal direction of the fixing unit 10 ', a pressurized state in which the pressure state of the pressure arm 4 can be released and the pressure released state can be maintained. A pressure release lever 15 is provided as pressure release means. The pressure release lever 15 is rotatably supported by a shaft 16 provided in the middle of the longitudinal direction above the receiving portion 4 of the pressure arm 4. In addition, the inner end of the pressure release example bar 15 is formed in a substantially cam-shaped pressing portion 15a which can push down the pressing arm 4.

The pressing portion 15a has an end formed in a plane, and grasps the outer end of the pressure releasing lever 15 and rotates the pressure releasing lever 15 in a clockwise direction to thereby release the pressure releasing lever 15a.
Is raised, the flat surface of the pressing portion 15a is brought into contact with the upper surface of the receiving portion 4a of the pressing arm 4 so that the pressing arm 4 can be held in a state of being pressed down. When the pressing arm 4 is pressed down, the pressing roller 2 pressed by the pressing arm 4 moves downward, and the fixing roller 1 moves downward by its own weight with the movement of the pressing roller 2. It has become.

As in the first embodiment, the surface of the fixing roller 1 is connected to the thermistor 1 via a thermistor spring 13a.
3, the temperature of the heater 17 can be controlled from the recording apparatus main body side by detecting the surface temperature of the fixing roller 1 by the thermistor 13. The thermistor may be fixed at a position where it contacts the surface of the fixing roller when the pressing arm is pressed.

The fixing unit 10 has a thermistor stopper 14 for regulating the amount of movement of the thermistor spring 13a.
Is provided, and the position of the thermistor stopper 14 is
When the pressure of the pressure arm 4 by the pressing portion 15a is released, the fixing roller 1 and the thermistor 13 can be separated by a distance D shown in FIG.

The fixing unit 10 'having the above structure is mounted on an image recording apparatus main body (not shown),
The pressure roller 2 is heated when the fixing roller 1 warmed by 7 rotates a driving force from a driving source (not shown) on the image recording apparatus main body side via a driving gear 18. At this time, the pressure generated by the spring 7 is applied to the receiving portion 4a of the pressing arm 4 swinging about the fulcrum 5 and transmitted as a pressing force for pressing the pressing roller 2 against the fixing roller 1. The paper (not shown) carrying the unfixed image passes between the fixing roller 1 and the pressure roller 2 which are rotated by the application of the pressure and the heat described above. The fixing is performed on the sheet by the pressing force, and the fixing process is completed.

When a jam occurs in the fixing process to the paper, the pressure release lever 15 is rotated clockwise about the shaft 16 as shown in FIG.
By raising the pressure release lever 15 above the pressure release lever 15, the pressurizing arm 4 is pressed down while compressing the spring 7 by the action of the pressing portion 15 a provided at the tip of the pressure release lever 15. As a result, the pressure roller 2 pressed and held by the pressure arm 4 is similarly pushed down, and the fixing roller 1 is lowered by its own weight following the downward movement of the pressure roller 2. At this time, the thermistor 13 fixed in the fixing unit 10 tries to follow the fixing roller 1 lowered by the action of the thermistor spring 13a.
Since the end of a is in contact with the thermistor stopper 14, the distance between the thermistor 13 and the fixing roller 1 is maintained at a distance D shown in FIG. 8, and the thermistor is damaged by the remaining and deformed paper or unfixed toner in this state. In addition, it is possible to perform a jam process or the like in which dirt, roller scraping, and the like are prevented.

After the jam processing, the fixing unit 1
When the use of 0 'is started, the contact state between the pressing portion 15a and the receiving portion 4a is released by rotating the pressure release lever 15 in the counterclockwise direction, and the pressure is applied by the restoring force of the spring 7. The arm 4 is pushed up so that the pressure roller 2 comes into contact with the fixing roller 1 and the thermistor 13 also properly contacts the surface of the fixing roller 1, so that the fixing is possible.

[0052]

As described above, according to the first aspect of the present invention, the fixing roller is pressed by the pressing means so that the fixing roller and the fixing roller are held by the roller holding member. The temperature detection means is brought into contact,
By releasing the pressurized state of the pressurizing means by the pressurizing releasing means and maintaining the depressurized state, the fixing roller moves in a direction away from the temperature detecting means along the roller holding member, so that the temperature of the fixing roller is reduced. Jam processing is performed in a state where the detecting means is separated from the detecting means, so that damage and contamination of the temperature detecting means and damage to the fixing roller can be prevented. Further, since a special control mechanism is not required, the number of parts can be reduced, the size of the main body can be reduced, and the cost can be reduced. At the same time, the simplification of the mechanism can reduce the causes of defects and improve the quality.

According to the second aspect of the present invention, the roller fixing device is locked to the main body of the image recording apparatus by pressing the fixing roller by the lock member provided in the pressure releasing means. With a simple configuration, it is possible to prevent forgetting to pressurize the fixing roller that occurs when the roller fixing device is replaced or the like. In addition, the roller fixing device can be detached from the image recording apparatus main body in response to the pressure release of the pressure release unit, and the fixing roller and the temperature detecting unit can be separated from each other to perform a jam processing or the like. It is possible to improve the workability of the apparatus management during processing and moving storage, and it is possible to prevent the temperature detecting member from being damaged due to the jam processing. In addition, there is no need to provide a member such as a spacer for preventing deformation of the roller, and the number of components can be reduced, and an image recording apparatus with good workability and low cost can be provided.

According to the third aspect of the present invention, when the fixing roller is pressed by the pressing member, the fixing roller and the temperature detecting means can be reliably brought into contact with each other. When the pressure of the fixing roller is released, the distance between the fixing roller and the temperature detecting means can be reliably ensured, so that damage to the temperature detecting means due to jam processing can be reliably prevented.

Further, according to the fourth aspect of the present invention, since the amount of movement of the temperature detecting means by the pressing of the pressing member is regulated by the regulating portion, the fixing roller can be more reliably used when the pressure of the fixing roller is released. The distance from the temperature detecting means can be ensured.

Further, according to the fifth aspect of the present invention, the recording material having a normal thickness can be fixed and fixed with a simple structure and operation by the decompression section provided in the pressure releasing means. The fixing can be performed by applying an appropriate pressure according to the type of the recording material to the recording material.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an image recording apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory side view illustrating a pressurized state of a fixing unit.

FIG. 3 is an explanatory side view illustrating a pressure release state of the fixing unit.

FIG. 4 is an explanatory front view showing a pressure release state of the fixing unit.

FIG. 5 is an explanatory front view showing a decompressed state of the fixing unit.

FIG. 6 is an explanatory side view showing a reduced pressure state of the fixing unit.

FIG. 7 is an explanatory side view showing a pressurized state in a fixing unit according to a second embodiment of the present invention.

FIG. 8 is an explanatory side view illustrating a pressure release state of the fixing unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Pressure release means 4 Pressure arm (Pressure means) 6 Roller holding member 7 Spring (Pressure means) 8 Lock member 13 Thermistor (Temperature detection means)

Claims (5)

[Claims] A fixing roller heated by a heating unit and pressed by a pressing unit; a temperature detecting unit abutting on the fixing roller to detect a surface temperature of the fixing roller; A roller fixing device having a pressure releasing means capable of releasing the pressure state and maintaining the pressure released state, wherein the pressurized and heated fixing roller fixes an unfixed image on the recording material by pressing force and heat. In the image recording apparatus provided, the fixing roller and the temperature detecting means can be kept in contact with the roller fixing device when the fixing roller is pressurized, and the fixing roller and the temperature are detected when the pressure of the fixing roller is released by the pressure releasing means. A roller holding member that can guide the movement of the fixing roller in a direction of releasing the abutting state with the unit, and that the temperature detecting unit and the fixing roller are separated from each other in synchronization with the pressure release of the pressure release unit. An image recording apparatus characterized in that the image is recorded. 2. The pressure releasing device according to claim 1, wherein the pressure releasing device is engaged with the image recording apparatus main body when the pressing device is in a pressurized state, and can maintain a mounted state of the roller fixing device to the image recording device. 2. The image recording apparatus according to claim 1, further comprising a lock member that releases the lock from the image recording apparatus main body in response to the release of the pressure and releases the state of mounting the roller fixing device to the image recording apparatus. . 3. The roller fixing device is provided with a pressing member for pressing the temperature detecting means against the surface of the fixing roller, and the pressing member is configured to reduce the amount of movement of the temperature detecting means by the pressing force of the pressing member. 3. The image recording apparatus according to claim 1, wherein the distance is smaller than a moving amount of the fixing roller in the pressure release state. 4. The roller fixing device is provided with a regulating portion that regulates the amount of movement of the temperature detecting means in the pressing direction by the pressing member, and the controlling portion controls the amount of movement of the temperature detecting means by the pressing of the pressing member. 4. The image recording apparatus according to claim 3, wherein the amount of movement of the fixing roller in a state in which the pressing unit is released from the pressure is smaller than the amount of movement of the fixing roller. 5. The pressure releasing means is provided with a pressure reducing portion capable of holding the pressure means in a pressure reduced state in the middle between the pressure applied state and the pressure released state, and the pressure contact member of the temperature detecting means is a pressure contact member. The amount of movement of the temperature detecting means due to the pressure contact of the fixing roller is smaller than the amount of movement of the fixing roller in the pressure releasing state of the pressing means. 5. The image recording apparatus according to claim 3, wherein the image recording apparatus is brought into contact with the image recording apparatus.