JP3731203B2 - Fixing apparatus, electrophotographic apparatus provided with the fixing apparatus, and fixing apparatus assembling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device in an electrophotographic copying machine, printer, facsimile machine, and the like. More specifically, the present invention relates to a fixing device structure having a small number of parts and easy to assemble. The present invention relates to an electrophotographic apparatus provided with the apparatus and an assembling method of the fixing apparatus .
[0002]
[Prior art]
Among the fixing devices in an electrophotographic apparatus, those using a heat roller with a built-in heater are configured to have a pressure roller that presses a recording paper carrying an unfixed toner image against the heat roller. However, since the heaters, heat rollers, and pressure rollers that constitute these fixing devices have different durability lives, Japanese Utility Model Publication No. 5-48207 discloses a heat roller and a pressure roller as an upper frame and a lower frame. Separately accommodated and arranged vertically, the heat roller and the pressure roller are pressed against each other, and a recording paper having an unfixed toner image is inserted into the nip portion for fixing. A fixing device is shown in which the pressure roller can be easily replaced.
[0003]
Recently, this type of fixing device is made of a heat-resistant resin as shown in Japanese Patent Laid-Open No. 9-16007 in order to reduce the size and weight, to reduce the cost, and to ensure heat retention. Things have been proposed. That is, in the apparatus disclosed in Japanese Patent Laid-Open No. 9-16007, the casing is made of a heat-resistant resin, and the rotation shafts of the heat roller and the pressure roller are pivotally supported by the reinforcing plate and are accommodated vertically in the casing. In addition, a support shaft that penetrates the reinforcing plate and serves as a fulcrum of the pressure lever is provided, and the casing is reinforced by the reinforcing plate and the support shaft.
[0004]
[Problems to be solved by the invention]
However, the apparatus disclosed in Japanese Utility Model Publication No. 5-48207 discloses a heating roller and a pressure roller as heating means, and a pressing means for pressing the pressure roller in the direction of the heat roller in a metal casing. Housed and equipped with an exterior cover made of heat-resistant resin for heat retention, ensuring operability at high temperatures, and adding a guide function, it requires a large number of parts, requires a lot of assembly steps, and is expensive. It was a fusing device.
[0005]
In addition, the apparatus disclosed in Japanese Patent Laid-Open No. 9-16007 requires a reinforcing plate made of a metal plate at both roller bearings for reinforcing the casing, and the casing is a rectangular casing. Since this bearing portion is provided on both sides in the longitudinal direction, it is weak against torsion and rotational load vibration, requires a pressure lever support shaft that reinforces the space between the frames, and has a difficulty in performance and the number of parts.
[0006]
SUMMARY OF THE INVENTION Accordingly, in view of the problems of the prior art, the present invention is a compact fixing device that has a small number of parts, that is easy to assemble and that is low in cost, an electrophotographic apparatus that is optimal for including this fixing device, and a method for assembling the fixing device. The purpose is to provide.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, the fixing device casing can be divided into a main body and a lid body in a direction substantially perpendicular to the recording paper conveyance direction, and a heat roller and a pressure roller pair are provided. It was designed to be housed in the main body. Then, the housing supporting the heat roller and the pressure roller on the main body side is divided into two rotatable about a fulcrum, and U-shaped portions having an open part are provided on each of the divided opposing surfaces, Each of the roller pairs is supported by the U-shaped portion, the housing is divided into two parts, and the roller pair is supported by the U-shaped portion provided in the housing, so The pressure roller can be easily replaced and assembled.
[0008]
The housing divided into two parts for supporting the heat roller and the pressure roller is provided with means for pressing the roller pair on the side opposite to the fulcrum, and ribs configured with bent portions on the left and right sides and the lower part of the housing. The fixing surface to the casing exists through the rib in parallel with the roller shaft so that the housing surface of the roller shaft surface does not bend even when a force is applied, and the rib surface is It was made to serve as a guide for fixing the housing to the body.
[0009]
In this way, the heat roller and the pressure roller can be assembled simply by inserting them into the U-shaped part provided in the housing, and the housing can be twisted or rotated with ribs provided on the left and right and the bottom, A fixing device that is resistant to vibration and the like can be constructed at low cost with a small number of parts.
[0010]
Therefore, in the present invention, in the fixing device in which the heat fixing roller pair is accommodated in the fixing device casing,
A housing that is housed in the fixing device housing and supports the pair of rollers is divided into two so as to be rotatable around a fulcrum, and U-shaped concave portions each having an open portion on each of opposing surfaces of the divided housing. The U-shaped concave portion supports each of the roller pairs, and the two divided housings are arranged around the fulcrum on the opening portion side opposite to the fulcrum of the two divided housings. Means is provided for pressing the roller pair by urging in the pulling direction.
[0011]
By constructing the housing that supports the roller pair in this way, as described above, the heat roller and the pressure roller can be assembled simply by inserting them into the U-shaped portion provided in the housing, and it is easy with a small number of parts. Thus, a fixing device that can be assembled and disassembled can be provided , and the pressure roller can be pressed against the heat roller with a simple configuration.
[0013]
Then the roller pair both side edge and the ribs at the bottom of the housing that supports provided, fixed surface of the roller shaft parallel to the fixing device casing is characterized in that exist as part of the rib.
By doing this, even if stress such as twisting or rotational load is applied, the housing itself is not bent by being absorbed by the ribs on both sides and the lower part, and the nip pressure between the heat roller and the pressure roller that are in contact with each other is kept constant. In addition, a fixing device that is resistant to vibration and the like can be configured at a low cost with a small number of parts.
[0014]
The fixing surface of the rib is used as a guide for fixing the housing.
By doing in this way, a housing | casing can be assembled easily and it can be functioned also as a reinforcement member of housing | casing itself.
[0015]
The housing of the fixing apparatus according to the present invention, serial substantially perpendicularly to Rokushi conveying direction, characterized by being dividable structure in the main body and a cover body accommodating the rollers.
By configuring the fixing device in this manner, it is possible to easily incorporate the heat roller and the pressure roller into the housing simply by removing the cover body constituting the fixing device, and to provide a fixing device that is easy to maintain. it can.
[0016]
In the electrophotographic apparatus according to the present invention, the line between the rotation center axes of the heat-fixing roller pair is configured to be substantially parallel to the horizontal direction of the electrophotographic apparatus, or the housing is divided. The reference plane is configured to be substantially parallel to the horizontal direction of the electrophotographic apparatus.
By forming such an electrophotographic apparatus, the fixing apparatus can be disposed in the middle of forming the substantially vertical conveyance path of the electrophotographic apparatus, workability when the fixing apparatus is mounted / removed, and when mounted in the apparatus It is possible to provide an electrophotographic apparatus that can improve the storability.
According to the present invention, in the fixing device assembling method for assembling the fixing device in the electrophotographic apparatus by accommodating the heat fixing roller pair in the fixing device casing, the fixing device casing is substantially in the recording paper conveyance direction. The housing that can be divided into a first and a second housing in a direction perpendicular to each other and that divides the housing that supports the roller pair into two so as to be rotatable around a fulcrum. it is provided a U-shaped recess having an open portion, respectively, a first step of supporting each of said rollers said divided housing by the U-shaped recess after assembly on the first housing, Means for pressing the roller pair by urging the two divided housings in the direction of pulling the two divided housings around the fulcrum on the open portion side opposite to the fulcrum of the two divided housings; Kicking fixing device assembling method characterized in that it comprises a second step is obtained.
Further, in the present invention, in the fixing device assembling method for assembling the fixing device in the electrophotographic apparatus by accommodating the heat fixing roller pair in the fixing device casing, the fixing device casing is substantially perpendicular to the recording paper conveyance direction. The housing that can be divided into first and second housings in the direction is divided into two so as to be rotatable about a fulcrum, and each of the opposing surfaces of the divided housings. A U-shaped concave portion having an open portion is provided, and each of the roller pair is supported by the U-shaped concave portion , and the two open portions on the side opposite to the fulcrum of the housing divided into the two parts, a first step of the assembly one the divided housings to each other to be biased in a direction to attract the fulcrum is provided with means for pressing the rollers, set the assembly to the first housing Fixing apparatus assembling method characterized in that it comprises a second step of writing can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an example.
[0018]
FIG. 1 is a perspective view of an embodiment in which a fixing device according to the present invention is divided, and FIG. 2 is a perspective view in which a first housing 1 and a second housing 2 of the fixing device in FIG. FIG. 3 is a perspective view of the fixing roller unit according to the present invention, FIG. 4 is a perspective view in which a front frame 6 and a rear frame 7 are disposed in the first housing 1, and FIG. 6 and 7 are perspective views in which the heat roller 3 is installed with the frame 6 and the rear frame 7, and FIGS. 6 and 7 show the first frame 1 with the front frame 6 and the rear frame 7 arranged at the reference portion of the frame. FIGS. 8 and 9 are views of the configuration in which the front frame 6 and the rear frame 7 are held at predetermined positions by the second casing 2 as viewed from the first casing 1 side.
[0019]
In the figure, 1 is a first housing as a main body containing the heat roller 3 and the pressure roller 4, 2 is a second housing as a lid for covering the heat roller 3 and the pressure roller 4, 3 Is a heat roller, 4 is a pressure roller, 5 is a heater, 6 is a front frame constituting a housing that supports the heat roller 3, 7 is a rear frame that also constitutes a housing that supports the heat roller 3, and 8 is fixed. Separation claw for separating the recording paper from the heat roller 3, 9 a drive gear, 10 a connector, 11 a recording paper conveyance path, 12 a bearing for the heat roller 3, 13 a bearing for the pressure roller 4, and 14 a pressure A pressure lever for constituting a part of a housing for supporting the roller 4 and pressing the pressure roller 4 against the heat roller 3, a pressure lever pin 15 rotatably supporting the pressure lever 14, and 16 Pressure roller Which is the spring as a means for pressing the heat roller 3.
[0020]
As shown in FIG. 1, the fixing device according to the present invention includes a first casing 1 and a second casing 2 made of a heat-resistant resin made of PET, PBT, or the like. The housing 2 is assembled as shown in FIG. 2 to form a fixing device. One of the first casings 1 includes a front frame 6 and a rear frame 7 constituting a housing for supporting a heat roller 3, a pressure roller 4, and a roller pair of the heat roller 3 and the pressure roller 4, and a part of the housing. And a fixing roller unit including a pressure lever 14 for supporting the pressure roller 4 and being in pressure contact with the heat roller 3 is mounted, and the recording paper is the heat roller 3 accommodated in the first housing 1. The sheet passes through the pressure roller 4 and is sent in the direction of the recording paper conveyance path 11 of the second housing 2. As is apparent from FIG. 1, the first housing 1 and the second housing 2 can be divided into a main body and a lid body that contain a pair of rollers in a direction substantially perpendicular to the recording paper conveyance direction. Has been.
[0021]
Among these, as shown in FIGS. 3 and 4, the front frame 6 and the rear frame 7 constituting the housing in the fixing roller unit mounted on the first housing 1 are formed of the heat roller 3 and the pressure roller 4. A rectangular shape is formed in the axial direction, a pressure lever 14 is pivotally attached to one end with a pressure lever pin 15 as a fulcrum, and a U-shape is formed on a surface facing the pressure lever 14 on one side of the longitudinal surface. Opening portions 17 and 18 which are recessed portions are provided. Further, the pressure lever 14 is provided with a U-shaped concave portion indicated by 19 in FIG.
[0022]
As shown in FIG. 5, the heat roller 3 fits and supports the heat roller bearings 12 in the U-shaped recesses 17 and 18 of the front frame 6 and the rear frame 7, while the pressure roller 4 The bearing 13 is fitted into and supported by a U-shaped recess 19 of the pressure lever 14. As shown in FIG. 3, the pressure lever 14, the front frame 6, and the rear frame 7 are coupled by a spring 16 provided on the opposite side of the fulcrum (pressure lever pin) 15, and the pressure roller 4 is a heat roller. 3 is pressed.
[0023]
Further, since the front frame 6 and the rear frame 7 cannot maintain strength in a planar shape, the shafts of the heat roller 3 and the pressure roller 4 when assembled on the side opposite to the U-shaped opening portion. Strength is ensured by forming bent portions (ribs) 6a and 7a substantially parallel to the entire length of the frame and ribs formed of bent portions (ribs) 6b, 7b and 6c on both sides of the short side. As shown in FIGS. 6 and 7, the first housing 1 is provided with a reference portion for fitting the ribs 6a, 7a and 6b, 7b, 6c of the front frame 6 and the rear frame 7, The front frame 6 and the rear frame 7 are held. The front frame 6 and the rear frame 7 can be attached to the reference portion by simply inserting them or by screwing them. The ribs 6b, 7b, 6c of the front frame 6 and the rear frame 7 also serve as a guide for fixing the second housing 2 together with the first housing 1, as shown in FIGS. Further, the ribs 6b and 6c of the front frame 6 are provided with mounting holes for connecting and holding the main body of the electrophotographic apparatus so that the fixing device can be fixed.
[0024]
As described above, the fixing device of the electrophotographic apparatus is divided into the first casing 1 and the second casing, and the heat roller 3 and the pressure roller 4 are accommodated in the first casing 1. 3 and the pressure roller 4 can be maintained very easily. Further, the heat roller 3 and the pressure roller 4 can be easily assembled from the open surface side of the U-shaped concave portion provided in the housing constituted by the front frame 6 and the rear frame 7. As shown in FIG. 4, the front frame 6 and the rear frame 7 are first assembled in the first housing 1, and then the pressure roller 4 is incorporated after the heat roller 3 is incorporated as shown in FIG. Conversely, the heat roller 3 and the pressure roller 4 can be incorporated into the housing constituted by the front frame 6 and the rear frame 7 and then incorporated into the first housing 1.
[0025]
The fixing device includes only the front frame 6 and the rear frame 7 constituting the housing, and the pressure lever, the heat roller 3 and the spring for pressing the pressure roller 4, and the fixing device has a small number of components. Can be configured at low cost. Further, the front frame 6 and the rear frame 7 constituting the housing are parallel to the axis of the heat roller 3 and the pressure roller 4 when assembled on the side opposite to the U-shaped opening as described above. Since the strength is ensured by forming the bent portions 6a and 7a on the entire length of the frame and the ribs composed of the bent portions 6b, 7b and 6c on both sides of the short side, stress such as twisting and rotational load is applied. Even if it is applied, it is absorbed by the left and right and lower ribs and the housing itself is not bent, the nip pressure between the heat roller 3 and the pressure roller 4 that are in pressure contact can be kept constant, and there are few fixing devices that are resistant to vibration and the like. Can be configured inexpensively with a score.
[0026]
FIG. 10 is a diagram showing an electrophotographic apparatus equipped with the fixing device 28 of the present invention, in which an image forming unit is disposed on a substantially vertical conveyance path, a paper discharge unit and a stock unit at the top, a paper feed device at the bottom, 2 is a cross-sectional view of an electrophotographic apparatus 21 having a double-sided conveyance path in the vicinity of a side cover facing an image forming unit of a vertical conveyance path, and includes a sheet feeding device 22, a sheet feeding roller 23, a registration roller 24, a transfer roller 25, and a photoreceptor And an image forming unit 26 including a peripheral unit such as an electric appliance, a laser unit 27, a first discharge branching unit 29, a second discharge branching unit 30, a pair of discharge rollers 31, a stack unit 32, and a double-sided conveyance path 33. .
[0027]
In operation, the recording paper is fed from the paper feeding device 22 to the registration roller pair 24 by the paper feeding roller unit 23 and sent between the image forming means 26 and the transfer roller 25 to print on the recording paper. Then, the toner on the recording paper is fixed by the fixing device 28, and the paper discharge roller pair 31 is discharged through the first discharge branching unit 29 and the second discharge branching unit 30, and is the upper surface of the electrophotographic device 21. Stocked in the stack unit 32. At the time of double-sided, a rotation of the paper discharge roller pair 31 is stopped with a little trailing edge of the recording paper stopped, and a switchback mechanism in which the paper discharge roller pair 31 reverses is adopted to pass through the double-sided conveyance path 33 to the registration roller pair 24. Re-conveyed and backside printing is performed.
[0028]
As described above, the sheet conveyance path of the electrophotographic apparatus 21 is a substantially vertical conveyance path, and the line between the rotation center axes of the heat roller 3 and the pressure roller 4 is configured substantially parallel to the horizontal direction of the electrophotographic apparatus 21. Or by configuring the divided reference plane that is divided in the direction substantially perpendicular to the sheet conveying direction of the first housing 1 and the second housing 2 substantially parallel to the horizontal direction of the electrophotographic apparatus 21, Since the first casing 1 and the second casing 2 of the fixing device 28 are placed on the electrophotographic apparatus 21 in a vertical state, the workability at the time of loading / unloading to / from the electrophotographic apparatus 21 is improved. Storability when placed on the battery is improved.
[0029]
【The invention's effect】
As described above, according to the present invention , the housing that supports the heat roller and the pressure roller is divided into two so as to be rotatable around a fulcrum, and each of the divided housings has an open portion. By providing the U-shaped recess, the heat roller and pressure roller can be assembled simply by inserting them into the U-shaped portion, and a fixing device that can be easily assembled and disassembled with a small number of parts can be provided. In addition, the pressure roller can be pressed against the heat roller with a simple structure by providing means for pressing the roller pair on the opening portion side opposite to the fulcrum of the housing divided into two. Can do.
[0031]
In addition, according to the present invention , the fixing surface to the housing is present via the rib in parallel to the roller shaft on the left and right and lower portions of the housing that supports the roller pair. Even if stress such as is applied, it is absorbed by the ribs on the left and right and bottom and the housing itself does not bend, the nip pressure between the heat roller and pressure roller that are in pressure contact can be kept constant, and a fixing device that is resistant to vibration etc. It can be configured inexpensively with a small number of parts.
[0032]
According to the present invention, the fixing surface of the rib can be used as a guide for fixing the casing so that the casing can be easily assembled and can also function as a reinforcing member for the casing itself. it can.
[0033]
Further, according to the present invention , the fixing device is configured by dividing the casing of the fixing device into a main body that accommodates the roller pair and a lid body in a direction substantially perpendicular to the recording paper conveyance direction. A heat roller and a pressure roller can be easily incorporated into the housing simply by removing the lid body, and a fixing device with easy maintenance can be provided.
[0034]
According to the present invention , the line between the rotation center axes of the heat-fixing roller pair is configured substantially parallel to the horizontal direction of the electrophotographic apparatus, or the divided reference plane into which the housing is divided is electrophotographic. Provided is an electrophotographic apparatus that is configured substantially parallel to the horizontal direction of the apparatus, thereby improving workability when the fixing device is attached to and detached from the electrophotographic apparatus and storage property when mounted on the electrophotographic apparatus. Can do.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment in which a fixing device according to the present invention is divided.
FIG. 2 is a perspective view in which a first casing 1 and a second casing 2 of the fixing device according to the present invention are assembled.
FIG. 3 is a perspective view of a fixing roller unit of the present invention.
FIG. 4 is a perspective view in which a front frame 6 and a rear frame 7 are disposed in the first housing 1 of the present invention.
FIG. 5 is a perspective view in which a front roller 6 and a rear frame 7 are disposed in the first housing 1 of the present invention and the heat roller 3 is incorporated.
6 is a diagram in which a front frame 6 is disposed in the first housing 1 and attached to a reference portion of the housing. FIG.
FIG. 7 is a diagram in which a rear frame 7 is disposed in the first housing 1 and attached to a reference portion of the housing.
FIG. 8 is a diagram showing the relationship between the front frame 6 and the second housing 2;
9 is a diagram showing a relationship between the rear frame 7 and the second housing 2. FIG.
FIG. 10 is a diagram showing an electrophotographic apparatus equipped with the fixing device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st housing | casing 2 2nd housing | casing 3 Heat roller 4 Pressure roller 5 Heater 6 Front frame 7 Rear frame 8 Separation claw 9 Drive gear 10 Connector 11 Recording paper conveyance path 12 Heat roller bearing 13 Pressure roller bearing 14 Pressurizing lever 15 Pressing lever pin 16 Spring 17 U-shaped recess 18 in front frame U-shaped recess 19 in rear frame 19 U-shaped recess in pressurizing lever pin

Claims (8)

In the fixing device in the electrophotographic apparatus in which the heat fixing roller pair is accommodated in the fixing device casing,
A housing that is housed in the fixing device housing and supports the pair of rollers is divided into two so as to be rotatable around a fulcrum, and U-shaped concave portions each having an open portion on each of opposing surfaces of the divided housing. The U-shaped recesses support each of the roller pairs, and the two divided housings are attracted around the fulcrum on the side of the opening opposite to the fulcrum of the two divided housings. A fixing device comprising means for urging the roller pair to press the roller pair. Ribs on both side ends and the bottom of the housing for supporting the rollers, fixed surface of the roller shaft parallel to the fixing device housing according to claim 1, characterized in that exist as part of the rib Fixing device. The fixing device according to claim 2, wherein a fixing surface of the rib is used as a guide for fixing to the fixing device casing.   3. The fixing device according to claim 1, wherein the fixing device housing is configured to be split into a main body and a lid body that accommodate a pair of rollers in a direction substantially perpendicular to the recording paper conveyance direction. .   5. The fixing device according to claim 1, wherein a line between rotation center axes of the heat fixing roller pair is configured to be substantially parallel to a horizontal direction of the electrophotographic apparatus. Electrophotographic device.   5. The fixing device according to claim 1, wherein a division reference plane into which the fixing device housing is divided is configured to be substantially parallel to a horizontal direction of the electrophotographic apparatus. Electrophotographic device. In a fixing device assembly method for assembling a fixing device in an electrophotographic apparatus by accommodating a heat fixing roller pair in a fixing device casing,
The fixing device housing can be divided into first and second housings in a direction substantially perpendicular to the recording paper transport direction, and the housing supporting the roller pair can be rotated about a fulcrum. And a U-shaped recess having an open portion on each of the opposing faces of the divided housing ,
A first step of supporting each of the roller pairs with the U-shaped recess after the divided housing is incorporated into the first housing;
A means for pressing the roller pair by biasing the two divided housings around the fulcrum is provided on the side of the opening opposite to the fulcrum of the two divided housings. fixing apparatus assembling method characterized in that it comprises a second step. In a fixing device assembly method for assembling a fixing device in an electrophotographic apparatus by accommodating a heat fixing roller pair in a fixing device casing,
The fixing device housing can be divided into first and second housings in a direction substantially perpendicular to the recording paper transport direction, and the housing supporting the roller pair can be rotated about a fulcrum. And a U-shaped recess having an open portion on each of the opposing faces of the divided housing ,
A direction in which the two divided housings are attracted around the fulcrum on the side of the opening opposite to the fulcrum of the housing divided into two by supporting each of the roller pair by the U-shaped recess. A first step for providing an assembly by providing means for urging the roller pair to press-contact the roller pair;
And a second step of incorporating the assembly into the first housing.

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