JPS63120914A - Roller pressure welding device - Google Patents

Abstract

PURPOSE:To prevent the deformation of a frame without increase in its strength when a paper shaped body rushes between two rotating bodies by stopping force acting on the secondary rotating body by a stopping means through the secondary bearing means when the paper-shaped body rushes between the nip parts of the primary and the secondary rotating body. CONSTITUTION:Housings 104 supporting an image carrying body drum 1 through bearings are fixed to a pair of frames 20, and eccentric cams fixed to the supporting shaft of a pressure transfer fixing roller 4 are supported by arms 27 through bearings. The protruding parts of the arms 27 are provided with pressure roller suspending means composed of wires 28 and spring devices 29, and the wires 28 are wound on the grooves of the housings 104 to suspend the fixing roller 4. On the other hand, a stopping means 33 is provided to stop force caused in a rushing direction on the arms 27 when a paper-shaped body rushes between the roller and the drum for preventing the displacement of the arms 27. Thus the deformation of the frames 20 can be prevented without increase in their strength at the time of rushing in of the paper shaped body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roller pressure contact device employed in image forming apparatuses such as copying machines and printers.

[Prior Art] Generally, in an image forming apparatus such as an electrophotographic copying machine, an electrostatic latent image corresponding to a document image is developed on an image bearing drum using a dry developer of a developing device, and then an electrostatic latent image corresponding to an original image is developed on the image bearing drum. Transfer is performed by pressing a paper sheet with a pressure roller.

By the way, the roller pressure welding devices currently in use place a huge load on the roller support member.
Since the roller support member needs to have a strong structure, there is a problem in that it is not possible to reduce the size and weight of the entire device.

In order to solve this problem, the applicant of the present application made various studies and proposed a roller pressure welding device having the structure shown in FIG. 10 in the previously filed Japanese Patent Application No. 128102/1982. This roller pressure contact device includes an image carrier drum 61,
drum bearing means 62 which are integrally provided at both ends of the drum 61 and rotatably support the drum 61;
1, a roller bearing means 64 that rotatably supports the pressure roller 63,
The pressure roller 63 is suspended between the drum 61 and the pressure roller 63 by a roller suspension means 65 that suspends a roller bearing means 64 from the drum bearing means 62. It is formed to generate pressure contact force.

In this way, the roller bearing means 64 of the pressure roller 63 is suspended from the drum bearing means 62 of the drum 61.
By applying pressure to the pressure roller, no strong pressing force is applied to the support frame 66 that supports both, and the structure of the support frame 66 made of 9M material can be simplified, making the roller pressing device more compact. , weight reduction can be achieved.

However, the pressing force between the drum 61 and the pressure roller 63 is applied to the roller bearing t164, and the positioning of the axis of the pressure roller 63 and the axis of the drum 61 is performed by the roller bearing means 6.
2 and the support frame 66. Moreover, in order to obtain a strong pressing force, it is necessary to increase the spring constant (modulus of elasticity) of the pressure roller 63. In such an ellipse, the first
As shown in FIG. 1, when a sheet of paper 67 is inserted between the drum 61 and the pressure roller 63, the nip between the drum 61 and the pressure roller 63 is expanded by the thickness of the sheet of paper 67. At the same time as a strong pressing force is applied, a large force is applied in the direction of arrow A. If the force in the direction of arrow A is calculated assuming that the pressing force is 800 kgf and the paper thickness is 0.12 nua, the value reaches about 40 kgf.

In addition, in order to improve the transfer band of the developer, reduce the impact when the transfer paper enters between the drum 61 and the pressure roller 63, and to equalize the pressure distribution, the drum 61 and the pressure roller 63 are When the axes of the rollers 63 intersect at a predetermined angle as shown in FIG. 12, the force in the direction of arrow A that acts on the pressure roller 63 when the sheet of paper 67 enters varies depending on the insertion position of the sheet of paper 67. , an imbalance occurs in the way forces are applied to both support frames 66.

The force in the direction of arrow A described above is applied to the pressure roller suspension means 65.
Since it has almost no rigidity in the direction perpendicular to the drum 61, it is received between the roller bearing means 64 and the support frame 66.

[Problems to be Solved by the Invention] In the above-mentioned prior art, since the structure is such that the strong pressing force between the drum 61 and the pressure roller 63 is not applied to the support frame 66, the support frame 66 is Rigidity is lower due to weight reduction. In addition, if an R-type mechanism is incorporated to separate the drum 61 and the pressure roller 63 as necessary, it is necessary to provide a gap between the pressure roller shaft and the support frame 66. As a result, when the paper sheet 67 enters between the drum 61 and the pressure roller 63, the roller shaft collides with the support frame 66 due to the force in the direction of arrow A acting on the pressure roller 63. may be deformed. If the support frame 66 is deformed in this way, there is a problem in that the relative positional relationship between the drum 61 and the image forming means is disturbed and the image is distorted. Further, increasing the strength of the support frame 66 in order to avoid such deformation of the support frame 66 is not a good idea in terms of weight reduction and cost.

The present invention has been made in view of the above-mentioned problems, and is a roller pressure welding device that can prevent the deformation of the support frame when a sheet of paper enters without increasing the strength of the support frame that supports both rotating bodies. The purpose is to provide

[Means and effects for solving the problems] The present invention
A second bearing means for rotatably supporting a second rotary body is suspended from the first bearing means for rotatably supporting the rotary body by means of a pressure roller suspension means, and the second bearing means for rotatably supporting the rotary body is suspended by a pressure roller suspension means. The roller pressure contacting device for bringing the second rotating body into pressure contact with the second rotating body is characterized in that a blocking means is provided for preventing movement of the second bearing means in the direction in which the sheet of paper enters. Since the force acting on the second rotary body in the direction of sheet entry can be stopped by the blocking means, no strong force is applied to the support frame.

[Example] An example of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the present invention is applied to an image forming apparatus using an ion flow type writing head. This image forming apparatus includes a writing head 2.0 that is provided with an ion flow generating device around an image bearing drum 1 as a first rotating body that rotates in a predetermined direction. Developing unit W3. A second rotating body such as a pressure transfer fixing roller 4. Toner removal device5. A static eliminator W6 is arranged. After forming an electrostatic image by projecting an ion flow modulated in accordance with the image signal to be recorded by the writing head 2 onto the image carrier drum 1, the developing device 3
The electrostatic image is developed with a torch, and the toner image is transferred and fixed onto the paper sheet 7 by a pressure transfer fixing roller 4.

The paper sheets 7 are stacked and stored in a paper feed tray 8, separated one by one by a separation roller, and sent to a transfer section by a paper feed roller 10. The paper sheet 7 that has been transferred and fixed in this transfer section is sent to a paper ejection tray 12 by a paper ejection roller 11.

On the other hand, the toner remaining on the image carrier drum 1 without being transferred to the paper sheet 7 is removed by the toner removing device 5, and the static charge on the image carrier drum 1 is eliminated by the static eliminator 6.

As shown in FIGS. 2 and 3, the roller press-contacting device according to this embodiment has a pressure transfer fixing roller 4 which is connected to an image bearing drum 1 by means of a pressure roller hanging means. It is configured to generate pressure contact force.

The image bearing drum l used here is constructed of an aluminum tube whose surface has been oxidized.

A front flange 101 and a rear flange 102 are integrally provided at both ends of the image carrier drum 1. Boss portions 101 of the front flange 101 and rear flange 102 made of carbon steel
In this embodiment, a housing 104.105 supporting the bearing 103.103 constitutes a first bearing means, and the housing 104, 105 is attached to a pair of unit frames. The image carrier drum 1 is rotatably supported by fixing the image carrier drum 1 to 20 and 20 using screws.

The pressure transfer fixing roller 4, which is disposed facing the image carrier drum 1, has a core metal 4a having an inner step formed on the inner walls at both ends of a steel pipe, and an outer side formed at one end of the outer periphery of the core metal 4a. It is composed of a synthetic resin vibrator 4b that is press-fitted into the outer periphery excluding the stepped portion. A bearing 401° 401 is press-fitted into the inner stepped portion of the core metal 4a, and the bearing 401,
A shaft 402 is inserted into the shaft 401 so that the pressure transfer fixing roller 4 can freely rotate around the shaft 402.

An eccentric cam 21 and a handle 22 are attached to one end of this shaft 402.
is fitted in a non-rotatable manner, and the plate 23 is pressed from outside of the handle 22 and fixed to the end surface of the shaft 402 using screws. In addition, an eccentric cam 24 is provided at the other end of the shaft 402.
is fitted in a non-rotatable manner, and a stop bar ring 25 is attached to the outside thereof.
In this embodiment, these eccentric cams 2 are fitted and fixed.
Arms 27.27 are fitted onto the circumferential surface of 1°24 via bearings 26.26 to constitute second bearing means.

A pressure roller suspension means consisting of a wire 28 and a spring device 29 with a tensioning mechanism is provided on the left and right protrusions of each arm 27, and the wire 28, 28 is wound around the arm of the housing 104, 105 to apply pressure. The structure is such that the transfer fixing roller 4 is suspended.

The above-mentioned roller pressure contact device rotates the handle 22 in a predetermined direction to apply pressure, and adjusts the length of the wire 28.28 with respect to the eccentricity of the eccentric cam 21.24. Appropriate pressing force is applied between the carrier drum 1 and the pressure transfer fixing roller 4. Also handle 2
2 in the opposite direction, the arm 27.27 moves and the tension on the wire 28.28 gradually decreases,
At the moment the end faces of the springs 29a, 29a come into contact with the bolts 29b, 29b, the force applied to the wires 28, 28 is only the weight of the pressure transfer fixing roller 4, and the force exerted by the springs 29a, 29a is released.

Further, the shaft 402 of the pressure transfer fixing roller 4 is supported by resin cross bearings 30.30 provided vertically slidably on the pair of unit frames 20.20, so that the axis 402 of the pressure transfer fixing roller 4 is It is configured to intersect the axis of the image carrier drum 1 at a predetermined angle. A hole sized to rotatably fit the shaft 402 of the pressure transfer fixing roller 4 is formed in the cross bearings 30, 30 at a position offset from the center between the sliding fitting parts. This cross bearing 30.
Flanges having different thicknesses are formed on both sides of the image carrier 30, and by changing the dimensions of the flanges, the intersection angle of the pressure transfer fixing roller 4 with respect to the image carrier drum 1 can be arbitrarily changed. In this case, since the speed vectors in the rotational direction at the contact portions of the image bearing drum 1 and the pressure transfer fixing roller 4 are different, a moving force in the thrust direction is applied to the pressure transfer fixation roller 4. Therefore, in this embodiment, by bringing the pressure ring 403 provided at the end of the pressure transfer fixing roller 4 into contact with the drum ring 106 provided at the end of the image bearing drum 1, the pressure transfer fixing roller 4 The image carrier drum 1 is prevented from moving relative to the image carrier drum 1.

Furthermore, mounts 32 and 32 for removably holding the write head cartridge 31 are integrally attached to the upper part of the pair of unit frames 20 and 20 that hold the image carrier drum 1 and the pressure transfer fixing roller 4.

On the other hand, reference numerals 33 and 33 are blocking means arranged near the arms 27 and 27 to prevent each arm 27 from moving in the direction in which the sheet of paper 7 enters. As shown in FIG. 4, this blocking means 33 has a screw hole formed in an L-shaped support 33a fixed to a substrate 34 at a position facing the protrusion of the arm 27.
By tightening a stopper 33b such as a bolt into this screw hole with a predetermined torque, a constant force is applied to the arm 27. At this time, the nut 33c is used to lock the stopper 33bcr) to prevent the arm 27 from moving in the paper sheet entry direction.

Therefore, according to such a configuration, by preventing the arms 27 and 27 constituting the second bearing means from moving in the paper sheet entry direction, the image carrier drum 1 and the pressurized When the sheet of paper 7 enters the nip portion with the transfer and fixing roller 4, the force applied to the pressure transfer and fixing roller 4 in the direction in which the sheet of paper enters can be stopped by the blocking means 33.33.

As a result, no strong force is applied to the unit frame 20.20, and deformation of the unit frame 20.20 can be prevented without increasing the strength of the unit frame 20.20. The relative positional relationship of the image forming means is not disturbed, and copy images of good quality can be obtained at all times.

Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 5 shows a schematic configuration of a roller pressure contact device according to a second embodiment of the present invention. In this second embodiment, an L-shaped support base 43, 43 fixed to a base plate 42 is used as a blocking means 41 for blocking the movement of each arm 27 constituting the second bearing means in the paper sheet entry direction. A pair of eccentric cams 45.45 are press-fitted into a shaft 44 which is rotatably supported by the arm 27.27, and each eccentric cam 45.45 faces the arm 27.27. A handle 46 is integrally provided at one end of the shaft 44. The rest of the structure is similar to that of the first embodiment, and the same parts are given the same reference numerals. In this case, in a roller pressure contact device that generates a large pressure contact force between the pressure transfer fixing roller 4 and the image carrier drum 1 by a pressure roller hanging means, the pressure transfer fixing roller 4 is By rotating the handle 46 when separating the eccentric cams 45, 45, the eccentric cams 45, 45 can be retracted to the position shown by the dashed line in FIG.

However, even with this arrangement, the same effects as in the first embodiment described in 1-1 can be expected, and the pressing force of the pressure transfer fixing roller 4 to the image carrier tram 1 can be easily released and applied.

FIG. 7 shows a schematic configuration of a roller pressure contact device according to a third embodiment of the present invention. In this third embodiment, as shown in the figure, a toggle is attached to a support base 53 fixed to a base plate 52 as a blocking means 51 for blocking the movement of each arm 27 constituting the second bearing means in the paper sheet entry direction. link 54
A pin 55 is installed at the rotating end of the toggle link 54, and the pin 55 is opposed to the protrusion of the arm 27. In this case, the lever portion 54a of the toggle link 54
By rotating clockwise in the drawing, the bottle 55 can be pressed against the arm 27 with a predetermined force. Also,
By rotating the lever part 54a counterclockwise,
The bottle 55 can be retracted to the position shown in the dashed line in FIG.

However, even with this arrangement, the same effects as in the second embodiment can be expected.

FIG. 8 shows a modification of the second embodiment, in which the eccentric cam 45 and the pressure release handle 22 are connected to the gear 47.
~49. In this case, the eccentric cam 45 can be retracted to the position shown by the dotted chain line in FIG. 9 by rotating and releasing the pressing force release handle 22 in the counterclockwise direction in the figure. With such a configuration, the blocking means can be automatically switched by rotating the pressure release handle 22, and the operation is extremely simple.

Note that the present invention is not limited to the above embodiments,
For example, in the above embodiments, the present invention was applied to a roller pressure contact device that performs transfer and fixing, but it may also be applied to a roller pressure contact device that performs only transfer, or a roller pressure contact device that only performs fixing. It can also be applied to pressure fixing machines that perform Further, in the case of interlocking the eccentric cam and the pressure release handle, a link chain or the like may be used instead of gears.

[Effects of the Invention] According to the present invention, when the paper sheet enters the nip portion between the first rotating body and the second rotating body, the force in the direction in which the paper sheet enters the second rotating body is reduced by the second rotating body. By stopping the receiver with the blocking means via the bearing means of 2, no strong force is applied to the support rod, so the deformation of the support rod due to the force generated when the paper sheet enters can be prevented without increasing the strength of the support. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of the configuration of an image forming apparatus to which the present invention is applied, FIG. 2 is a perspective view showing a roller pressure contact device according to a first embodiment of the present invention, and FIG. 3 is a perspective view of the same roller pressure contact device. FIG. 4 is an explanatory view showing the main parts of the same embodiment; FIG. 5 is a perspective view showing a roller pressure welding device according to a second embodiment of the present invention; FIG. FIG. 7 is a perspective view showing a roller pressure welding device according to a third embodiment of the present invention, and FIG. 8 is a roller pressure welding device according to a fourth embodiment of the present invention. A perspective view showing the device, FIG. 9 is an explanatory view showing the main parts of the fourth embodiment, FIG. 10 is a perspective view showing an example of a conventional roller pressure welding device, and FIGS. 11 and 12 are explanations of the same device. It is a diagram. 1... Image carrier drum 103.26... Bearing 104.105... Housing 4... Pressure transfer fixing roller 21.24... Eccentric cam 27... Arm 28... Wire 29 Spring device 33.41.51 Blocking means Applicant Olympus Optical Industry Co., Ltd. N2 Figure 3 Figure 4 Figure 5 Figure 4 Co. Figure 7 Figure 9 Figure 10

Claims (1)

[Claims] The second bearing means for rotatably supporting the second rotary body is suspended from the first bearing means for rotatably supporting the first rotary body by a pressure roller suspension means, and the first rotary body is 1. A roller pressure contact device for bringing the second rotating body into pressure contact with each other, characterized in that the roller pressure contact device includes a blocking device that prevents the second bearing device from moving in the direction in which the sheet of paper enters.