JP2000275992A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus excellent in quality and durability capable of reliably performing jam processing without causing wrapping jam. An upper rotation member and a lower rotation member (guide member) guide a recording material in an exit area of a nip portion of a fixing film and a pressure roller. Is provided with a position changing means for changing the position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copier having a heat fixing means for nipping and conveying a recording material and heating an image, and a guide member for guiding the recording material from the heat fixing means to a discharge side.
The present invention relates to an image forming apparatus such as a printer and a facsimile.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus, for example, there are a copying machine, a printer, a facsimile machine and the like.

A copying machine generally has a function of reading an image of a document or the like and forms an image on a recording material based on the read image information. There is also a copying machine having a function of inputting image information sent from a copier.

[0004] A printer generally forms an image on a recording material based on image information sent from an external device such as a computer.

A facsimile apparatus generally has a function of reading an image of a document or the like and a communication function, sends the read image information to the outside, and prints the image on a recording material based on the image information sent from the outside. An image is formed.

As described above, all of the apparatuses form an image on a recording material based on the obtained image information.

In these apparatuses, after an image is formed on a recording material, a heat fixing means for heating the image and a guide member for guiding the image from the heat fixing means to a discharge side are provided.

Referring to FIG. 7, a description will be given of a heat fixing unit and a guide member provided in an image forming apparatus according to the prior art.

FIG. 7 is a schematic structural view of the vicinity of the image forming apparatus according to the prior art where the discharge means having a guide member is provided.

As shown in the figure, a recording material P having an unfixed toner image T formed on its surface is conveyed from the right side in the figure by an image forming means (not shown), and a fixing roller 101 and a pressure roller It is sent to the heating nip N formed by 102.

The fixing roller 101 has a heater 101 a and a heat-resistant film F, and the pressure roller 102 is configured to press the fixing roller 101.

With this configuration, the heating nip N
Is pressed and heated to fuse and fix the unfixed toner image T to the recording material P that conveys the toner image.

Then, the pressure roller 102 rotates in the direction of the arrow in the figure to convey the recording material P downstream.

The film F is driven by the rotation of the pressure roller 102.

The conveyed recording material P is placed on a discharge member 105.
Is guided to the holding portion between the roller 103 and the discharge roller 104, and further conveyed downstream to be discharged outside the apparatus.

The interval between the upper discharge member 105 and the lower discharge member 106 on the upstream side of the holding portion between the roller 103 and the discharge roller 104 has a shape gradually narrowing so that the recording material P can be easily guided to the holding portion. ing.

Rotating fixing roller 101 and discharge member 1
Reference numeral 05 denotes a pressure roller 1 which is disposed at an interval X and rotates.
02 and the lower discharge member 106 are arranged at an interval Y.

The fixing roller 101 and the pressure roller 102 are required to have a releasing property, and contact with other members is not preferable in terms of durability. Usually, the interval X and the interval Y are always required to maintain the durability performance.

Since the temperature of the fixing roller 101 as a heating element reaches a high temperature, the temperature of peripheral members rises remarkably, and the interval X is set to be larger than the interval Y in order to prevent sticking and accumulation of scattered toner on the discharge member 105. Often done.

Here, the roller 103 is held by the upper discharge member 105, and the discharge roller 104 is held by the lower discharge member 106.

Further, there is another conventional example in which the end of the recording material P after passing through the heating nip N is urged and a peeling claw for peeling off the fixing roller from the fixing roller is sacrifice in durability performance.

[0022]

However, in the case of the above-described prior art, the following problems have occurred.

For example, in an image forming apparatus, a fixing roller 101 and a pressure roller 102 for fixing an unfixed image are used.
The surface property is deteriorated with the use period due to toner scattering, fixing failure, jam processing, and the like.

For this reason, when the recording material P once passed through the heating nip portion N enters the space X between the fixing roller 101 and the discharge member 105 and winds around the fixing roller 101 having the reduced releasability. There was (wrapped jam).

Similarly, the recording material P once passing through the heating nip portion N is rotated by the pressing roller 102 and the lower discharge member 106.
In some cases, the recording material P enters the recording material P at the interval Y, and is wrapped around the pressure roller 102 having reduced releasability.

The same occurs when a paper jam occurs in the discharge unit of the image forming apparatus or when the discharge port is closed.

In such a case, in particular, when the roller is wrapped for one round or more, the jam cannot be cleared and a serviceman call is made.

Further, in the wrapping jam in which the leading end of the recording material P is discharged, it is not possible to visually recognize that the recording material P has been wound. May be completely wound around the fixing roller 101 and the pressure roller 102 in some cases.

Then, by using the wound recording material P,
Extreme image defects due to defective fixing may occur, or a failure of the apparatus body may be caused.

Further, in the conventional example in which the peeling claw for peeling the recording material P after passing through the heating nip portion N from the fixing roller 101 is arranged while urging the same, an extra load is constantly applied to the fixing roller 101 continuously. For this reason, there is an inconvenience that the surface of the fixing roller is easily damaged, the print quality is deteriorated, and the like.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to improve the quality and durability to prevent the occurrence of wrapped jam and to perform the jam processing without fail. An object of the present invention is to provide an excellent image forming apparatus.

[0032]

According to the present invention, there is provided an image forming means for developing an electrostatic latent image formed on an image carrier and transferring the latent image to a recording material. A heating and fixing unit for fixing the unfixed developed image by nipping and conveying the recording material to which the unfixed developed image has been transferred at a nip portion of a rotating member to be heated, and a recording material after image fixing. A guide member for guiding the recording material from the heating and fixing unit to a discharge side, wherein the guide member is capable of changing a guide position for guiding the recording material in a nip exit area of the heating and fixing unit. It is characterized by comprising a position changing means.

Further, the position changing means may be configured such that the guide member which takes a first position for setting the distance from the heating and fixing means to a predetermined value in a normal operation state of the apparatus, and the distance from the heating and fixing means to the predetermined value. It is also preferred that the position can be changed to a second position smaller than the value.

Further, the position changing means is configured to contact the recording material after the image is fixed, which is to be separated from the center position of the conveying path to be conveyed, along the heating and fixing means, by the contact force. It is also preferable that the position of the guide member can be changed from the first position to the second position.

It is also preferable that the position changing means includes a rotating shaft for rotating the guide member from the first position to the second position.

The position changing means includes an urging means for urging the guide member to be held at the first position, and an urging force of the urging means against the guide member is applied to the recording material. It is also preferable that the setting is smaller than the contact force.

It is preferable that the urging means is a spring member.

It is also preferable that the urging means is a helical spring that applies a rotating force about the rotating shaft to urge it.

Further, the guide member has an upper guide member for guiding above the conveyed image-fixed recording material, and a lower guide member for guiding below the recording material. It is also preferable that the heating apparatus includes a heating element and a pressure roller, and the interval is an interval between the upper guide member and the heating element or between the lower guide member and the pressure roller.

An image forming means for developing the electrostatic latent image formed on the image carrier and transferring the developed image to a recording material, and the recording material to which the unfixed developed image has been transferred are rotated by a rotating member to be heated. An image forming apparatus comprising: a heat-fixing unit that fixes the unfixed developed image by nipping and conveying at a nip portion; and a guide member that guides a recording material after image fixing from the heat-fixing unit to a discharge side. In the above, the guide member may be brought into contact with a recording material after image fixing which is to be separated from a center position of a conveying path conveyed along the heat fixing unit in a nip portion exit region of the heat fixing unit. Accordingly, the recording material is an elastic body whose guide position can be changed.

[0041]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However,
The dimensions, materials, shapes, relative positions, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified.

(Embodiment 1) An image forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention, and FIGS. 2, 3 and 4 are image forming apparatuses according to the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of main parts of FIG.

In the present embodiment, a laser beam printer utilizing an electrophotographic process will be described as an example of an image forming apparatus.

First, the outline of the image forming means of the image forming apparatus will be described with reference to FIG.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a rotating drum) as an image carrier. First, the surface of the rotating drum 1 is uniformly charged by the primary charger 2 during the rotation process.

Next, a scanning exposure with a laser beam L modulated corresponding to a time-series electric digital image signal of target image information is performed on the charged surface of the rotating drum 1 by scanning exposure.
Output from the laser scanner 3, an electrostatic latent image corresponding to target image information is formed on the surface of the rotating drum 1.

Next, the electrostatic latent image is reversal-developed with the negative toner T by the developing device 4 (toner adheres to the laser-exposed portion).
And visualized.

On the other hand, the recording material P is separated and fed one by one from the paper feed cassette 20 by the paper feed roller 21, and is transferred via a registration roller pair 22 to a transfer nip portion between the rotary drum 1 and the transfer roller 5. The toner image on the surface of the rotating drum 1 is sequentially transferred to the surface of the recording material P by being conveyed and introduced into the unit at a predetermined timing.

The recording material P that has passed through the transfer section is
Is transferred to an image fixing / ejecting device 7 having a heating / fixing unit, and is subjected to a fixing process of the transferred toner image, and is ejected outside the machine as a print by the ejecting unit.

After the separation of the recording material, the surface of the rotary drum 1 is cleaned by the cleaning device 23 after removing the residual contaminants such as transfer residual toner and the like, and the work is repeatedly performed.

The printer shown in this embodiment is a process cartridge in which four process devices of a rotary drum 1, a primary charger 2, a developing device 4, and a cleaning device 23 are collectively attached to and detached from the printer main body. 24.

Next, the image fixing and discharging device 7 having the heat fixing means will be described with reference to FIGS. 2, 3 and 4. FIG.

The image fixing and discharging device 7 has a heating means and a discharging means of a tension-free type film heating system, and these will be described in detail below.

For convenience, JP-A-63-313182, JP-A-1-263679, and JP-A-2-157.
No. 878, JP-A-4-44075-444083,2
An image forming apparatus having an image fixing / discharging device having both a heating means of a film heating method disclosed in Japanese Patent No. 04980-204498 and a discharging means of a heated recording sheet will be described as an example.

First, the heat fixing means and the discharging means will be described.

Such a heating means of the film heating system can be used, for example, in an image forming apparatus such as a copying machine, a laser beam printer, a facsimile, a micro film reader printer, an image display (display) device, and a recorder. Indirectly to the surface of a recording medium (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper, etc.) by using a toner made of a heat-meltable resin or the like by an appropriate image forming process means such as electric recording and magnetic recording. The present invention can be used as an image fixing device that heats and fixes an unfixed toner image corresponding to target image information formed by a (transfer) method or a direct method as a permanently fixed image.

As the heating element having a low heat capacity and a rapid temperature rise, a ceramic material substrate having heat resistance, insulation, and good thermal conductivity and a heat generation portion as an electric heating portion formed on the substrate by printing, firing, or the like are provided. A ceramic heater having a low heat capacity and a high temperature as a whole is used, which has a resistance part as a basic structural body and supplies power to the heat generation resistance part to generate heat.

The heat fixing means described in the present embodiment is disclosed in Japanese Patent Application Laid-Open Nos. 4-44075-44083, 204980-204.
No. 984, etc., a heating roller uses a cylindrical film as a heat-resistant film and rotates the film with a pressing roller as a pressing means. That drives the film without applying tension).

In the figure, reference numeral 14 denotes a horizontally elongated thin plate-shaped heating element (hereinafter referred to as a heater) whose length is perpendicular to the drawing.

The heater 14 is generally a low-heat-capacity ceramic heater having a ceramic substrate and a heat-generating resistor provided on the substrate surface by printing or firing.

The heater 14 has heat resistance, insulation,
TaSiO2, AgPd, TA2N, Ru formed on a high thermal conductive alumina substrate by screen printing, for example.
The fixing film 9 has a thin-film heat-generating resistor such as O2 or nichrome, and the surface facing the inner surface of the fixing film 9 is overcoated with heat-resistant glass or the like.

Reference numeral 10 denotes a heater support which also serves as a film guide of a horizontally long gutter type having a substantially semicircular cross section, and a heater 1 is provided at the center of the lower surface of the heater support 10 along the longitudinal direction of the support.
4 is fixedly supported by a heat-resistant adhesive or the like.

Reference numeral 9 denotes a cylindrical (endless belt), thin heat-resistant film (hereinafter referred to as a fixing film or a film) loosely fitted to a heater support 10 supporting a heater 14.

The fixing film 9 is a single-layer film having heat resistance, toner release property and toughness, or a composite layer film subjected to a desired surface treatment or laminating treatment.

The fixing film 9 is made of polyimide (P
I) Film is preferred, heat-treated 50 um Z
no monolayer film or tetrafluoroethylene (PTF
A composite layer film subjected to the release property imparting treatment in E) can be obtained.

Reference numeral 15 denotes flange members provided at both ends of the heater support 10 to receive the ends of the fixing film and restrict the shifting of the fixing film 9.

Reference numeral 11 denotes an elastic pressure roller as a pressure member, which presses the lower surface of the heater 14 of the heater support 10 with a predetermined contact pressure against the roller elasticity with the fixing film 9 interposed therebetween. Thus, a heating nip portion N as a heating portion having a required width is formed.

That is, the heater 14 and the pressure roller 11 sandwich a predetermined pressure (for example, A
4 widths and a total pressure of 4 to 10 kg).

The pressure roller 11 is driven to rotate in a counterclockwise direction indicated by an arrow by a drive system (not shown).

The rotational force acts on the fixing film 9 by the frictional contact between the outer surface of the pressing roller 11 and the outer surface of the fixing film 9 due to the rotation of the pressing roller 11 at the heating nip portion N. While its inner surface is in sliding contact with the lower surface of the heater 14, it is driven to rotate around the outer periphery of the heater support 10 in the clockwise direction indicated by the arrow.

The heater support 10 also serves as a guide for the rotating fixing film 9.

In a state where the fixing film 9 is rotated by the rotation of the pressure roller 11 and the heater 14 is heated to a predetermined temperature (for example, 150 degrees or more) by energizing the heating resistor, the pressure roller 11 and the fixing film 9, the recording material P on which the unfixed toner image T is formed and carried is conveyed to the heating nip portion N.

At this time, the recording material P is introduced into the heating nip portion N together with the fixing film 9 by introducing the recording material P through the conveyance guide with the toner film surface facing the fixing film 9. The recording paper P is heated by the heater 14 via the fixing film 9 so that the unfixed toner image T is softened and fused.

The recording material P that has passed through the heating nip N is separated from the fixing film 9, and is pinched and conveyed by a roller 51 and a discharge roller 41 forming a pair of rotating members through an upper discharge member 50 and a lower discharge member 40. Is discharged to the outside of the image forming apparatus.

This device is used to press the pressure roller 1 of the fixing film 9.
In the rotating state by the drive of No. 1, except for the heating nip portion N, substantially no tension acts on the fixing film 9, and therefore, the fixing film 9 rotates along the length of the heater support 10. Along the film-side moving force, the film-side moving control means can be simplified,
There are advantages such as easy assembling and cost reduction.

Reference numeral 8 denotes an upper cover for preventing the user from touching the components of the device that become hot.

Reference numeral 30 denotes a frame on which the flange member 15, the pressure roller 11, the upper discharge member 50, the lower discharge member 40, and the upper cover 8 are disposed.

Next, the position changing means on the upper side of the discharge member 50 will be described.

As shown in the figure, 70 is the upper part of the discharging member.
The upper rotation member is an upper guide member as a guide member rotatably supported by a rotation shaft at 0.

Reference numeral 70a denotes the posture of the upper rotating member 70,
Are ribs provided to maintain the interval between the fixing film 9 and the fixing film 9 at a predetermined value X necessary for normal operation of the apparatus.

Reference numeral 70b denotes a position after the upper rotating member 70 is rotated by the contact force caused by the contact of the recording material P, and a distance between the upper rotating member 70 and the fixing film 9 as a second position. Predetermined set value Xa required to prevent winding
Ribs provided to maintain

Reference numeral 71 is provided above the upper rotating member 70,
A spring member (spring) is a pressing member that presses the outer surface of the upper turning member 70 and urges the recording medium P in a direction that regulates the turning direction of the upper turning member 70 by the contact force.

As described above, since the spring member 71 is provided, the posture of the upper turning member 70 is set to the first position, which is the interval between the fixing film 9 and the fixing film 9 in a normal operation state of the apparatus, after the jam processing. It is possible to reliably and automatically return to the predetermined value X.

With the above configuration, when a jam occurs near the discharging means, as shown in FIG.
The recording material P moves away from the center position of the transporting path to be transported,
PA, P, P
B, begins to wrap around with PC.

When the recording material P is wound around the fixing film 9, the recording material P comes into contact with the upper turning member 70, and the upper turning member 70 turns with the contacting force of the upper turning member 70A, 70B. The rib 70b is rotated to a position 70C at which a predetermined set value Xa required to prevent the recording material P from winding around can be set as a position.
Is maintained in posture.

Further, in the normal operation state of the apparatus, the posture of the upper turning member 70 is changed to the first position, ie, a predetermined value X which requires a distance from the fixing film 9 by the rib 70a.
Can be maintained.

Therefore, by providing the upper rotating member 70 which is rotatably supported on the discharging member 50, the upper rotating member 70 is brought into contact with the recording material P by the contact force of the recording material P at the initial stage of the occurrence of the wrapping jam. The second position, the winding prevention, is determined from the first position X, which is a predetermined value X for preventing contact damage and preventing adhesion and accumulation of scattered toner. The recording material P can be prevented from winding around by allowing the setting value Xa to be changed to the set value Xa.

The set value Xa is in the range of 0 ≦ Xa <1 mm.
Winding can be effectively prevented.

The detection of the wrapping jam and the activation of the position change of the guide member for the prevention of the wrapping are based on the contact force of the recording material P, so that no special detecting means or complicated members are required.
It can be implemented at low cost.

In the normal operation state of the apparatus, the upper rotating member 70 is in the first position, and the distance between the upper rotating member 70 and the upper discharge member 50 and the fixing film 9 is a predetermined value X. No damage due to contact with the fixing film 9 and no sticking or accumulation of scattered toner on the upper rotation member 70 and the discharge member 50 occur.

Next, the position changing means on the lower side of the discharge member 40 will be described.

As shown in the figure, 80 is the lower part of the discharge member 4.
Reference numeral 0 denotes a lower rotating member which is rotatably supported by a rotating shaft and is a lower guide member as a guide member.

Reference numeral 80a designates the posture of the lower rotating member 80 as the first position.
Are ribs provided to maintain the interval between the pressure roller 11 and the pressure roller 11 at a predetermined value Y necessary for normal operation of the apparatus.

Reference numeral 80b denotes a position after the lower rotating member 80 is rotated by the contact force caused by the contact of the recording material P, and a distance between the pressure roller 11 and the second position. Predetermined set value Ya required to prevent P from winding
Ribs provided to maintain

Reference numeral 81 is provided below the lower rotating member 80,
A spring member (spring) is a pressing member that presses against the outer surface of the lower rotating member 80 and urges the lower rotating member 80 in a direction that regulates the rotating direction of the lower rotating member 80 due to the contact force of the recording material P.

As described above, by providing the spring member 81, the posture of the lower rotary member 80 is set to the first position, which is the distance between the lower rotating member 80 and the pressure roller 11 after the jam clearance, so that the apparatus can be operated normally. The required predetermined value Y can be reliably and automatically returned to.

With the above configuration, when a jam occurs near the discharge means, as shown in FIG.
The recording material P moves away from the center position of the transporting path to be transported,
PD, P, P
Start winding around with E and PF.

When the recording material P is wound around the pressure roller 11, the recording material P comes into contact with the lower turning member 80, and the lower turning member 80 turns with the contact force of the lower turning member 80D and 80E. Is rotated to 80F at which a predetermined set value Ya required for preventing the recording material P from winding around can be set as the position of the rib 80b.
Is maintained in posture.

Further, in a normal operation state of the apparatus, the posture of the lower rotating member 80 is changed to the first position, a predetermined value Y which requires an interval from the pressure roller 11 by the rib 80a.
Can be maintained.

Therefore, by providing the lower rotating member 80 rotatably supported on the lower discharge member 40, the lower rotating member 80 is brought into contact with the recording material P at the initial stage of the occurrence of the wrapping jam. Rotate, lower the discharge member 40 and the pressure roller 1
The interval 1 can be changed from a first value Y, which is a first position, which is for preventing contact breakage, and prevents sticking and accumulation of scattered toner, to a second value, which is a set value Ya for preventing winding. Thereby, it is possible to prevent the recording material P from being wound.

The set value Ya is in the range of 0 ≦ Ya <1 mm.
Winding can be effectively prevented.

The detection of the wrapping jam and the activation of the position change of the guide member for the prevention of the wrapping are performed by the contact force of the recording material P, so that no special detecting means and complicated members are required.
It can be implemented at low cost.

In the normal operation state of the apparatus, the lower rotating member 80 is in the first position, and the interval between the lower rotating member 80 and the lower discharge member 40 and the pressure roller 11 is a predetermined value Y. Also, damage due to contact with the pressure roller 11 and sticking and accumulation of scattered toner on the lower rotating member 80 and the lower discharge member 40 do not occur.

In the present embodiment, the position of the guide member can be changed by the contact force of the recording material P. However, the recording material which is going to move away from the center position of the conveyance path is detected, and the control means controls the guide member. The position may be changed.

When a recording material having a small thickness and easy to wind is used, a switch for jam prevention and a control means are provided on the operation panel of the apparatus, and the user selects the jam prevention mode in advance before the apparatus is operated. Alternatively, the position of the guide member may be changed, or the position of the guide member may be changed every time the recording material passes through the nip exit area of the fixing unit.

Further, the guide member may be made of an elastic material, and the guide member may be elastically deformed by the contact of the recording material to change the guide position.

(Embodiment 2) FIGS. 5 and 6 show a second embodiment of the present invention.

In the first embodiment, the outer surfaces of the upper turning member 70 and the lower turning member 80 are pressed by the spring as the urging means, and are required for the normal operation of the apparatus as the first position. Although the configuration in which the predetermined value X can be reliably and automatically returned to has been described, in the present embodiment, the rotation of the upper rotation member 70 and the lower rotation member 80 is performed by a winding spring as the urging means. A configuration is shown in which a turning force can be applied to the center to reliably and automatically return to the predetermined values X and Y required for the normal operation state of the apparatus as the first position.

[0110] Other configurations and operations are described in the first section.
Therefore, the same components are denoted by the same reference numerals and description thereof will be omitted.

FIG. 5 is a schematic configuration diagram of a main part of an image forming apparatus according to a second embodiment of the present invention, and FIG. 6 is a main part of the image forming apparatus according to the second embodiment of the present invention. FIG.

In the figure, reference numeral 72 denotes a winding spring which is provided at the center of rotation of the upper rotating member 70 and serves as urging means for applying a rotating force in a direction for regulating the rotating direction of the upper rotating member 70. .

As described above, by providing the winding spring 72, the upper rotating member 70 is automatically and reliably returned to the predetermined value X required for the normal operation of the apparatus as the first position. be able to.

In the figure, reference numeral 82 denotes a winding spring which is provided at the center of rotation of the lower rotation member 80 and serves as urging means for applying a rotational force in a direction for restricting the rotation direction of the lower rotation member 80. .
It is arranged similarly to the winding spring 72 of FIG.

As described above, by providing the winding spring 82, the lower rotating member 80 is automatically and reliably returned to the first position, the predetermined value Y required for the normal operation of the apparatus. be able to.

Also, in the present embodiment, the upper rotating member 70 and the lower rotating member 80 are different from the structure in which the outer surfaces of the upper rotating member 70 and the lower rotating member 80 are pressed as in the first embodiment. Moving member 8
Since no space for disposing the urging means (spring) is required on the outer periphery of the zero, the device can be made compact.

[0117]

As described above, according to the present invention,
Since the guide member includes the position changing unit, it is possible to prevent the recording material from being wound around the heat fixing unit, and to provide an image forming apparatus having excellent quality.

Further, since the guide member is located at the first position where the distance between the guide member and the heating and fixing means is a predetermined value in a normal operation state of the apparatus, the guide member may be damaged by contact with the heating and fixing means or may be damaged by the guide member. The scattered toner does not stick or accumulate, and even if a wrapping jam occurs, the position changing means can change the position of the guide member to the second position at the initial stage of the jam occurrence, so that the recording material Can be prevented from wrapping around the heat fixing means, and a highly reliable image forming apparatus can be provided.

Further, the position changing means can change the position of the guide member by the contact force caused by the contact of the recording material after the image is fixed, so that no special detecting means or complicated members are required, and the position changing means can be simplified. With a simple configuration, it can be implemented at low cost.

Further, by providing a rotating shaft that rotatably supports the guide member, it is possible to implement the present invention at a low cost with a simple configuration that does not require a complicated member.

Further, by providing the urging means, in a normal state, the guide member is urged by the urging means, and the interval between the guide member and the heating / fixing means can be reliably maintained at a predetermined value.

Further, when the biasing means is a spring member,
It can be easily implemented, and if it is a wound spring, space efficiency is good and miniaturization is possible.

Since the guide member is an elastic body that can change the position of the guide member by the contact force caused by the contact of the recording material after the image is fixed, it does not require any special detection means or complicated members. With a simple configuration, the recording material can be prevented from winding around the heating and fixing unit at low cost, and a highly reliable image forming apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a main part of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a main part of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a main part of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a main part of an image forming apparatus according to a second embodiment of the present invention.

FIG. 6 is a schematic perspective view of a main part of an image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a main part of a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1 rotating drum 2 primary charger 3 laser scanner 4 developing device 5 transfer roller 7 image fixing and discharging device 8 fixing upper cover (device upper cover) 9 fixing film (heat resistant film) 10 heater support 11 pressure roller 14 heater (heat generation) 15) Flange member 20 Paper feed cassette 21 Paper feed roller 22 Registration roller pair 23 Cleaning device 24 Process cartridge 30 Frame 40 Lower discharge member 41 Discharge roller 50 Upper discharge member 51 Roller 70 Upper rotation member (guide member, upper guide member) 70a, 70b Rib 80 Lower rotating member (guide member, lower guide member) 71, 81 Spring member (biasing means) 72, 82 Winding spring (biasing means) P Recording material

Claims (9)

[Claims] An image forming means for developing an electrostatic latent image formed on an image carrier and transferring the developed image to a recording material, and rotating the recording material on which an unfixed developed image has been transferred by rotating the recording material An image fixing device comprising: a heat fixing unit for fixing the unfixed developed image by nipping and conveying the image at a nip portion of the member; and a guide member for guiding a recording material after image fixing from the heat fixing unit to a discharge side. In the image forming apparatus, the guide member includes a position changing unit configured to change a guide position for guiding the recording material in a nip exit area of the heat fixing unit. 2. The apparatus according to claim 1, wherein the position changing unit is configured to move the guide member having a first position that sets a distance between the heating and fixing unit to a predetermined value in a normal operation state of the apparatus. The image forming apparatus according to claim 1, wherein the second position can be changed to a value smaller than the value. 3. The image forming apparatus according to claim 1, wherein the position changing unit is configured to contact the recording material after the image is fixed to be moved away from a center position of the transporting path along the heating and fixing unit. The image forming apparatus according to claim 2, wherein the position of the guide member can be changed from a first position to a second position. 4. The image forming apparatus according to claim 2, wherein the position changing unit includes a rotation shaft that rotates the guide member from the first position to the second position. . 5. The position changing means includes an urging means for urging the guide member to be held at the first position, and an urging force of the urging means against the guide member is applied to the recording material. The image forming apparatus according to claim 2, wherein the contact force is set to be smaller than the contact force. 6. The image forming apparatus according to claim 5, wherein said urging means is a spring member. 7. The image forming apparatus according to claim 5, wherein the urging unit is a helical spring that applies a rotational force about the rotating shaft to urge the urging force. 8. The fixing device according to claim 1, wherein the guide member includes an upper guide member that guides the recording material after the conveyed image is fixed, and a lower guide member that guides a lower portion of the recording material. 8. The apparatus according to claim 2, further comprising a heating element and a pressure roller, wherein the interval is an interval between the upper guide member and the heating element or between the lower guide member and the pressure roller. 9. The image forming apparatus according to claim 1. 9. An image forming means for developing an electrostatic latent image formed on an image carrier and transferring the developed image to a recording material, and rotating the recording material on which an unfixed developed image has been transferred by rotating the recording material. An image fixing device comprising: a heat fixing unit for fixing the unfixed developed image by nipping and conveying the image at a nip portion of the member; and a guide member for guiding a recording material after image fixing from the heat fixing unit to a discharge side. In the forming apparatus, the guide member is configured such that a recording material after image fixing, which is distant from a center position of a conveying path to be conveyed along the heat fixing unit, is applied to a nip portion exit area of the heat fixing unit. An image forming apparatus comprising: an elastic body that can change a guide position for guiding the recording material by being in contact with the image forming apparatus.