JPS61212874A - Fixing device - Google Patents

Abstract

PURPOSE:To obtain a fixing device supporting securely a pressure roller by forming the pressure roller rotatably attached to a fixing roller with a cylindri cal core bar pipe member and inserting and supporting the bearing hole of a bearing inserted and fixed on both inner sides of a pipe into a projecting part installed on a supporting member. CONSTITUTION:The pressure roller 42 rotatably attached to the fixing roller of an electronic copying machine is formed with the cylindrical core bar pipe member 44. Bearings 46 and fixed with a retaining ring 61. On the other hand, the supporting arm 48 provided with the projecting part 62 formed by press drawing of a sheet metal material is prepared. The bearing hole 46a of the bearing 46 fixed on the core bar pipe member 44 is inserted into the projecting part 62 of the arm 48, and the fulcrum of the arm 48 and an axial center of a roller 42 are aligned in a coaxial center direction. Thus the structure and fitting of the pressure roller is simplified, and moreover it can be securely supported.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a fixing device installed in an image forming apparatus such as an electronic copying machine.

[Technical background of the invention and its problems]

In image forming apparatuses such as copying machines, the one illustrated in FIG. 4 has been put into practical use. In this case, a document (not shown) is placed on a document mounting table 2 formed on the top surface of an apparatus main body 1 in which an upper unit and a lower unit can be separated and opened and closed, and the top surface is pressed by a document holding cover 3. Next, the original image on the original platen 2 is transferred onto the photosensitive drum 10 via the fixed reflecting mirror 9 by the moving scanning of an exposure optical system consisting of an exposing lens 4, a plurality of reflecting mirror groups 5, 6.7, and a lens 8. By performing slit exposure and forming an image, an electrostatic latent image is formed on the photosensitive drum 10, which has been uniformly charged in advance by the charging charger 11, and then developed by the developing device 12. On the other hand, the paper P in the upper cassette 14 or the lower cassette 15 set in the feeding section 13 is transported by the feed rollers 16 or 17, or the paper P inserted through the manual feed guide 19 of the manual feed port 18 is moved by the aligning roller. 20 and fed through the respective feed channels 21, 22, 23 to the distro roller 2.4. Then, the developer image on the photosensitive drum 10 is transferred onto this paper P by the transfer charger 26 of the transfer section 25.

Next, the paper P that has been electrostatically attracted to the photosensitive drum 10 after the transfer is peeled off from the photosensitive drum 10 by the peeling charger 29 and conveyed to the fixing device 31 via the conveying device 30. is discharged onto a paper discharge tray 33 by a discharge roller 32. After the transfer, the photosensitive drum 10 is cleaned by a cleaning device 27, and the static electricity is removed by a static eliminator 28.

In such an apparatus main body 1, an upper frame and a lower frame (not shown) are pivoted so as to be openable and closable at a desired angle (for example, 30 degrees), and exposure optical systems 4, 5, 6.7 are provided on the upper frame side. 8.9, photosensitive drum 10, charger 11, developing device 12, cleaning device 27, and static eliminator 2
8 and the like are arranged by appropriate means to constitute an upper unit. On the other hand, on the lower frame side, there is a feeding section 13, a transfer charger 26, a peeling charger 29, a conveying device 30. Each device, such as the fixing device 3 and the ejection roller 32, and other mechanisms such as a power supply unit (not shown) are arranged to constitute a lower unit. and,
Both units can be opened and closed vertically with the conveyance path of paper P as the boundary, making it easy to repair and inspect the inside of the apparatus.

However, in the fixing device 3 in the conventional apparatus described above, a heat roller 41 as a fixing roller is attached to the upper frame side of the apparatus main body 1, and a pressure roller 42 is attached to the lower frame side to close both the upper and lower units. In this state, both rollers 41 and 42 can come into pressure contact with each other.

As shown in FIGS. 5 to 7, the pressure roller 42 attached to the lower frame side is a cored pipe material 4 made of a cylindrical body whose outer peripheral side surface is covered with an elastic material 43 such as rubber.
Bearing hubs 45 serving as bearings are attached to both sides of 4 by welding, pressure welding, or the like. Furthermore, a pair 1J ring 46 is attached to the bearing 45, and is fitted and supported in the notch 48a of the support arm 48 which is biased by the pressure spring 47, and one end of the support arm 48 is inserted into the elongated hole 48. It is pivotally supported by a fixed shaft 50 inserted through the shaft so that it can swing vertically.

On the other hand, the other end is pivotally supported on a horizontal end 52a of an L-shaped pressurizing arm 52 rotatably supported on a support shaft 5 fixed to the lower frame of the main body 1 of the apparatus. This pressure arm 5
By pressing the holder part 53 attached to the vertical end 52b of 2 with the upper unit when both units of the device main body 1 are closed, the pressurizing arm 52 is
As shown in the figure, the support arm 48 is rotated in the direction of the solid line arrow and the support arm 48 is rotated in the direction of the dotted line arrow. As a result, the pressure roller 42 held by the support arm 48 is pressed against the upper roller 41 and brought into rolling contact with the upper roller 41. However, with such a conventional configuration, the support arm 48 may come off the bearing 46 due to the force applied by the upper unit during use. In addition, a bearing 46 is attached to the core bar/branch material 44 that forms the pressure roller 42.
Since it is necessary to attach a bearing 45 that serves as a bearing, the structure becomes complicated and the cost increases.

[Purpose of the invention]

The present invention has been made under the above circumstances, and an object of the present invention is to provide a fixing device that can simplify the support structure of the pressure roller and reduce costs.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides a fixing device in which a pressure roller that is in rolling contact with a fixing roller is supported by supporting means that is elastically biased via a bearing. The pressure roller is formed of a cylindrical core metal or tube material, and bearings are inserted into both ends of the core metal and base tube material. The shaft hole of the bearing is inserted into and supported by the bearing.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIGS. 1 to 3. In the illustrated embodiment of the present invention, the same reference numerals are used for the parts having the same configuration as the conventional structure shown in FIGS. 4 to 7, and the explanation thereof will be omitted.

That is, the present invention improves the support structure of the pressure roller 42 constituting the fixing device 31 in the conventional device, particularly the support means for the support arm 48.
Instead of holding the bearing 46 in the notch 48a cut out at 8, as shown in FIGS.
Bearings 46 are inserted into the inner sides of both ends and fixed with retaining rings 61. On the other hand, the support arm 48 is formed of a sheet metal material, and a protrusion 62 that becomes a pivot support is provided on the inner surface of the support arm 48 by pressing.
Both ends of the core metal pipe material 44 are attached to the protruding portions 62 protruding from the
The pressure roller 42 is pivotally supported by a support arm 48 by inserting a shaft hole 46a of a bearing 46 fixed to the support arm 48.

Therefore, according to the above configuration, the fulcrum of the support arm 48 is located on the axial center line of the pressure roller 42 and is in the same phase as the axial center of the bearing 46, so that pressing during use is performed by force. The support arm 48 does not come off the bearing 46 as in the conventional case. Since the protruding portion 62 of the bent support arm 48 can be easily formed by press working, there is no need for the use of studs or bearings, and the structure is simple and cost reduction can be expected.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that insertions and modifications can be carried out without changing the gist of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, when supporting the pressure roller, the pressure roller is formed of a cylindrical core metal material, and bearings are inserted and fixed inside both ends of the core metal and base material. Since the shaft hole of the bearing is inserted into a protrusion provided in the support member, the structure and installation of the pressure roller is simple, reliable support is possible, and costs can be reduced. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of essential parts showing an embodiment of the fixing device according to the present invention, FIG. 2 is a sectional view showing the support state of the pressure roller, FIG. 3 is an exploded perspective view, and FIG. The figure is a schematic explanatory diagram of an image forming apparatus, FIG. 5 is a schematic side view of the main parts of a conventional fixing device, FIG. 6 is a sectional view showing the support state of the pressure roller, and FIG. 7 is an exploded perspective view. It is a diagram. 31... Fixing device, 4... Fixing roller (heat roller), 42... Pressure roller, 44... Core metal i9
Idea material, 46...Bearing, 46a...Shaft hole, 4
7... Pressure spring, 48... Support arm, 6
2...Protrusion. l field

Claims (2)

[Claims] (1) In a fixing device in which a pressure roller that is in rolling contact with a fixing roller is supported by supporting means that is elastically biased via a bearing, the pressure roller is made of a cored pipe material made of a cylindrical body. A fixing device characterized in that a bearing is inserted into both ends of the cored pipe material, a protrusion is provided on the support means, and a shaft hole of the bearing is inserted and supported by the protrusion. (2) The fixing device according to claim 1, characterized in that the support means is constituted by a support arm made of a sheet metal material, and the protrusion is formed on the support arm by pressing.