JP3881501B2 - Fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device in an image forming apparatus such as a copying machine, a printer, or a facsimile machine using an electrophotographic method, and more particularly to a fixing device in which a casing serving as an outer wall can be divided into a plurality of parts.
[0002]
[Prior art]
In the conventional fixing device, a heating unit such as a heat roller and a pressing unit such as a driving unit and a press roller are arranged in a box shape in which a metal stay is combined with a metal frame, and each temperature sensor around the heating unit is arranged. Is attached to a metal stay, and a plurality of exterior covers, recording paper guides, discharge guides, separation means attachment members, heater terminal connection bases, protective covers and the like are attached to the outer surface of the metal frame. Furthermore, a configuration has been implemented in which the opening / closing means of the separating means attaching portion and the metal frame are divided and opened in the recording paper conveyance direction by improving JAM processing.
[0003]
FIG. 7 is a cross-sectional view showing a conventional fixing device, in which recording paper is conveyed in a substantially horizontal direction (XX line direction) in the drawing, and a heat roller 14, a press roller 15, a separation claw 16, a thermistor 17, and a thermostat. 18, a heater 19, a discharge roller pair 20, a lower stay base 21, an upper stay base 22, and a separation unit 23. The lower stay base 21 and the upper stay base 22, which are metal materials indicated by hatching, The metal side plate is formed in a box shape, and functional members such as a heat roller 14, a press roller 15, a thermistor 17, a thermostat 18, and a heater 19 are attached inside. FIG. 8 is a view showing a state when the upper exterior cover attached to the upper stay base 22 of the fixing device of FIG. 7 is removed, and is configured in a box shape with a side plate front 24 made of a metal material.
[0004]
[Problems to be solved by the invention]
However, in the conventional fixing device, a sheet receiving guide portion, a discharge guide portion, an exterior cover, and a separation claw 16 are provided around the outside (the lower stay base 21 and the upper stay base 22) which are formed in a box shape with a metal material. In order to attach the separation unit 23 and the like, there is a problem that the number of parts increases.
[0005]
Further, as an improvement in JAM processing, a mechanism for opening and closing the separation unit 23 at the fulcrum A in the direction of the arrow a, or a mechanism for allowing the upper case to be opened and closed at the fulcrum B in the direction of the arrow b. There is. However, in such a configuration, the heat roller 14 and the press roller 15 are separately attached to the two cases, and the strength of the entire fixing device is deteriorated. The upper surface of the upper casing is not visible because the contact surface of the thermistor 17 or the thermostat 18 attached to the upper casing to be divided cannot be seen. The problem is that there are many assembly work steps that need to be opened, and furthermore, when supporting and fixing in the image forming apparatus, the fulcrum spans two cases like C and D, so the strength is the case frame. There was a problem that I could not receive it.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and in a fixing device for fixing a toner image on a recording paper, a casing whose outer wall is an exterior surface of the device can be divided in a direction substantially perpendicular to the recording paper conveyance direction. This is a fixing device. Specifically, in the fixing device shown in FIG. 7, the housing is not divided along the XX line as in the prior art, but is divided into two along the YY line that is substantially perpendicular to the recording paper conveyance direction. Alternatively, the housing on the left side in the drawing is further divided into T-shaped housings divided by the YY ′ line.
[0007]
With such a configuration, two rollers (heat roller and press roller) can be collectively attached to one housing, and the strength of the entire fixing device can be increased as compared with the case where only one conventional roller is attached to the housing. It is possible to confirm the performance because the contact surface of the thermistor and the thermostat can be seen, and it is possible to check the performance. Furthermore, since the fulcrum C and D supported by the image forming apparatus main body is a single housing, the housing strength is used. it can. And by this strength increase, a housing | casing can be integrally molded by using heat-resistant resin, and it becomes possible to further reduce assembly efficiency and a housing | casing component number. The heat-resistant resin of the present invention may be a resin that is also used in a conventional fixing device, and means a material that does not deform due to the heat generated by the heater of the fixing device.
Further, according to the present invention, the divided housing forms at least a recording paper transport opening and a part of the guide, and holds the components in the apparatus on the inner wall of at least one housing. A fixing device in which a reference portion for forming a wiring portion for wiring an electric wire in the device is formed, or a fixing device in which a thermistor, a thermostat, and a reference portion for attaching a temperature substrate are formed on the inner wall of at least one housing; It is characterized by that. In addition , a position holding reference part for holding the position of the component parts arranged in the reference part is provided on the inner wall of one or more casings other than the one casing, and the reference part of the one casing is provided with It is also effective to provide a fixing device in which all the component parts in the apparatus are arranged and the position of the component parts is held by attaching one or a plurality of casings other than the one casing. Specifically, in the fixing device shown in FIG. 7, the components are arranged in the case on the right side in the drawing of the case divided by the YY line instead of being divided by the XX line as in the prior art. In addition, these components are used as a fixing device whose position is maintained when the left housing is attached in the drawing.
[0009]
With such a configuration, the number of parts can be greatly reduced, and all the internal components can be mounted by rotating the housing on the right side of the drawing sideways, that is, 90 ° clockwise from the state shown in FIG. As a result, the assembly can be made easier.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, an image forming unit is arranged on a substantially vertical conveyance path, a paper discharge unit and a stock unit at the upper part, a paper feeding device at the lower part, and a double-sided conveyance path in the vicinity of a side cover facing the image forming part of the substantially vertical conveyance path. 1 is a cross-sectional view of a configured image forming apparatus 1, and includes a sheet feeding device 2, a sheet feeding roller 3, a registration roller pair 4, a transfer roller 5, image forming means 6 including peripheral devices such as a photoreceptor and a charger, and a laser unit 7. A fixing device 8, a first discharge branching unit 9, a second discharge branching unit 10, a pair of paper discharge rollers 11, a stack unit 12, and a double-sided conveyance path 13.
[0011]
The operation will be described below.
The sheet is fed from the sheet feeding device 2 to the registration roller pair 4 by the sheet feeding roller unit 3 and is fed between the image forming unit 6 and the transfer roller 5 to print on the sheet. Then, the toner on the sheet is fixed by the fixing device 8, and the normal discharge is performed from the discharge roller pair 11 through the first discharge branching unit 9 and the second discharge branching unit 10, and the upper surface of the image forming apparatus 1. Is stored in the stack unit 12. At the time of double-sided printing, a rotation of the sheet discharge roller pair 11 is stopped with the trailing edge of the sheet remaining slightly, and a switchback mechanism that reversely rotates the sheet discharge roller pair 11 is adopted. It is transported and backside printing is performed.
[0012]
FIG. 2 shows the fixing device of the present invention, and shows a state where the fixing device 8 of FIG. 1 has been taken out, and the discharge opening 27 visible on the upper surface becomes the discharge conveyance path after fixing. In the fixing device 8 of the present invention, the first casing 25 and the second casing 26 which are casings divided into two along the YY line are assembled without being divided along the XX line in FIG. Features.
[0013]
FIG. 3 is a view showing the first housing 25, the sheet entry opening 28 (see FIG. 4 because it is not visible on the bottom surface), the fixing side plate front 29, the fixing side plate rear 30, and the apparatus positioning portion 31 (visible on the right side). 4), the temperature substrate 32 is shown. In FIG. 3, the wires of the heater 19, the thermistor / thermostat 18, the temperature substrate 32, and the like are omitted.
[0014]
The present invention is characterized in that the reference portion for attaching the components inside the fixing device is integrally formed on the inner wall of the first housing 25, and for example, a complicated shape is molded from a resin that is easy to mold. With such a configuration, the number of parts can be greatly reduced while maintaining the strength of the fixing device 8.
[0015]
Specifically, the first casing 25 is positioned on the upper surface in the drawing, which is the inner wall of the fixing device 8, with the reference section and mounting section for mounting the components inside the fixing, and the positioning of the second casing 26. A part, an attachment part, and a reinforcement rib are comprised, and the lower surface on drawing becomes an outer wall. On the inner wall, a fixing side plate front 29 and a fixing side plate rear 30 to which a pressure member is attached are arranged at a reference portion that has sufficient strength, and the thermistor 17 (see FIG. 4 because it cannot be seen under the heat roller 14) and the thermostat. 18 and the temperature substrate 32 are attached, and wiring is also performed in the first housing 25. Here, 14 is a heat roller, 15 is a press roller, 33 is a connector, 36 is a wiring portion, and 37 is a heater wire.
[0016]
FIG. 4 is a diagram illustrating a state in the middle of assembling the component parts in the first housing 25, and a wiring portion 36 for wiring the electric wire is formed in a part of the first housing 25. A certain heater wire 37 is connected to the connector 33 via the wiring portion 36. Electric wires such as the thermistor 17, the thermostat 18, and the temperature substrate 32 are also connected to the connector 33 via the wiring portion 36. Further, the inner wall is erected so as to serve as a reference portion in a shape that can hold each component, and is integrally formed with the first housing 25 that is a resin.
[0017]
FIG. 5 is a diagram showing a state in the middle of assembling the components in the first housing 25 from the state of FIG. 4, and shows a state in which the assembly of the heat roller 14 and the connector 33 is completed in the first housing 25. FIG.
[0018]
FIG. 6 is a view when the assembly of the component parts from the state of FIG. 5 to the first housing 25 is completed and the first housing 25 and the second housing 26 are combined. In FIG. A drive unit 35 that receives drive from the main body is a pressure spring for pressing the heat roller 14 and the press roller 15 together. The second housing 26 is provided with a separation claw 16 attached to the discharge opening 27 serving as an outer wall, and a position holding reference portion for holding the position of the component parts disposed on the reference portion of the inner wall of the first housing 25 on the inner wall. In the same manner as the first housing 25, the inner wall is integrally formed with resin. The resin used in the first casing 25 and the second casing 26 may be a heat-resistant resin that can be used as a fixing device, and may be PET or the like.
[0019]
Then, by attaching the second housing 26 to the first housing 25 from the state of FIG. 6, the fixing device 8 is completed as shown in FIG. In this way, the exterior surface portion that is a stable flat surface into which the sheet enters and exits can be divided into a direction substantially perpendicular to the sheet conveyance direction and all the components inside the fixing device can be attached to the inner wall of one housing. As a work table surface, it can be assembled and work efficiency can be dramatically improved.
[0020]
In the present embodiment, the fixing device having a housing that is divided into two at the YY line in FIG. 7 has been described. For example, the YY ′ line in FIG. It may be a fixing device having a casing that is mold-divided.
[0021]
【The invention's effect】
As described above, according to the fixing device of the present invention, the housing whose outer wall is the exterior surface of the device can be divided in a direction substantially perpendicular to the recording paper conveyance direction, and further, the housing is heat resistant resin. By forming the reference part for holding the components in the apparatus on the inner wall of at least one casing, or on the inner wall of one or a plurality of casings other than one casing By providing a position holding reference part that holds the position of the component parts arranged in the reference part and arranging all the component parts in the device in the reference part of one housing, the number of parts can be greatly reduced. Therefore, it is possible to provide a fixing device that can attach and wire components from the inside of the housing, improve the assembly work efficiency, maintain and maintain the process strength, and is small and low in cost. Furthermore, parts can be easily replaced during maintenance such as parts replacement, and can be easily disassembled and assembled. Therefore, it is possible to provide a fixing device that considers environmental measures such as recycling.
[Brief description of the drawings]
FIG. 1 is a diagram showing an image forming apparatus equipped with a fixing device of the present invention.
FIG. 2 is a view showing a fixing device of the present invention.
FIG. 3 is a diagram illustrating a state in which components are incorporated in the casing of the fixing device of the present invention.
FIG. 4 is a diagram illustrating a housing of the fixing device of the present invention.
FIG. 5 is a diagram illustrating a state in which components are incorporated in a housing of the fixing device of the present invention.
FIG. 6 is a diagram illustrating a state in which the housings of the fixing device of the present invention are combined.
FIG. 7 is a diagram illustrating the present invention and a conventional fixing device.
FIG. 8 is a diagram illustrating a conventional fixing device.
[Explanation of symbols]
1: Image forming device 2: Paper feeding device 3: Paper feeding roller 4: Registration roller pair 5: Transfer roller 6: Image forming unit 7: Laser unit 8: Fixing device 9: Discharge branching means A
10: Discharge branching means B
11: Paper discharge roller pair 12: Stack unit 13: Double-sided conveyance unit 14: Heat roller 15: Press roller 16: Separation claw 17: Thermistor 18: Thermostat 19: Heater 25: First housing 26: Second housing 27: Discharge opening 28: Entrance opening 29: Fixing side plate front 30: Fixing side plate rear 31: Device positioning unit 33: Connector 34: Drive unit 35: Pressure spring 36: Wiring unit 37: Heater wire

Claims (4)

A fixing device that fixes a toner image on a recording paper using a heat roller and a press roller that are pressed against each other using a pressure spring, and a housing whose outer wall is an exterior surface of the device is substantially perpendicular to the recording paper conveyance surface direction. In the fixing device in which a dividing line is provided in the direction so that the dividing line can be divided into the first and second housings,
The first casing is made of heat-resistant resin, and the outer wall, the recording paper transport opening, a part of the guide section, and the electrical component mounting part are attached by resin integral molding, and the heat roller, the press roller, and their drive A pair of side plates for supporting the part is fitted into the reference part,
The pressure spring is stretched over the free end of the side plate that is not fitted into the first housing,
The fixing device according to claim 1, wherein the second casing is formed of a heat-resistant resin so that an outer wall, a recording paper conveyance opening and a part of the guide portion are formed by resin integral molding, and a recording paper conveyance separation claw is attached. The fixing device according to claim 1, wherein the electrical components are a thermistor, a thermostat, and a temperature substrate. A fixing device comprising: an inner wall of the second casing provided with a position holding reference portion for holding a side plate embedded in the first casing by resin integral molding. The fixing device according to claim 1, wherein a reinforcing rib is formed on an inner wall of the first casing .

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