JPH0450882A - Transfer material separation device for image forming device - Google Patents

Abstract

PURPOSE:To maintain the abutting angle of a separation pawl with respect to the surface of an image carrier to be constant and to always realize stable and sure separation by providing a means which sets and maintains the direction of the separation pawl which separates a transfer. CONSTITUTION:Counterclockwise turning habit shown by a figure is given to a holder 4 by a spring 8. Besides, a roller 11 and the separation pawl 6 which is concentric with the roller 11 are provided on a pawl supporting piece provided at an end part on the image carrier side of the holder 4. then, the roller 11 abuts on and it is connected to the image carrier by the action of the spring 8 and a distance DELTAE between the center thereof and the surface of the image carrier is secured. Therefore, the angle that the pawl 6 abuts on the surface of the image carrier is maintained. Thus, the relative arrangement of the separation pawl 6 and a rotating body 10 is excellently set and the stable separation is always executed.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) This invention relates to an image forming apparatus that uses an electrostatic transfer process, such as an electrostatic copying machine or a printer, and It is related to the device.

(Prior art and problems to be solved) A structure in which a transferable toner image is formed on the surface of an image carrier, and a transfer material such as paper is brought into contact with this to electrostatically transfer the toner image to the transfer material. In the well-known image forming apparatus, the transfer material tends to be electrostatically attracted to the image carrier during transfer, so it is necessary to actively separate the transferred transfer material from the image carrier using an appropriate separation means. There is.

Various types of separation means have been proposed in the past for this purpose, but a separation claw is brought into contact with the image carrier, and the transfer material that is adsorbed to the image carrier even after transfer is peeled off by the separation claw. Since it is possible to perform more reliable separation than electrostatic separation means, devices configured to allow separation have been widely used in the past.

By the way, in a device that uses such a separation claw, the separation claw is made of a relatively hard material and has a sharp tip, and is configured such that the sharp end comes into contact with the image carrier. If the photosensitive layer is in constant contact with a certain part of the surface of the image carrier, there is a risk that the photosensitive layer on the surface of the image carrier may be damaged, resulting in subsequent deterioration of image quality.

In order to avoid such inconveniences, for example, the separation claw is configured to reciprocate in the axial direction of the image carrier, which is usually formed in a rotating cylindrical shape, so that the tip of the separation claw is attached to the surface of the image carrier. A configuration has been proposed that prevents contact only at a specific position.

This is a typical example, and will be briefly described below.

Fig. 3 is a side view showing an example of a transfer material separation device using separation claws, in which a toner image force "ff) is formed by an image forming member (not shown) on an image bearing member 1o rotating and traveling in the direction of the arrow shown in the figure. As the carrier rotates, the toner image is transferred to the image carrier 1.
When the transfer material (not shown) is supplied to the transfer site from the conveyance path 12 at the same timing, the toner image is transferred by the transfer bias applied to the transfer device. Transfer to transfer material.

At this time, the transfer material tends to be electrostatically attracted to the image carrier 10 and tends to adhere to it and rotate. Therefore, it is necessary to separate the transfer material from the image carrier (in the axial direction of the image carrier 10). A suitable number of separation claws (only one is shown in the figure) 6 are provided to separate the transfer material that has arrived at this position from the image carrier and convey it to the fixing site. Place it on the conveyance path 9.

The separation claw 6 is rotatably held by a claw support piece 5 provided near one end of the holder 4 formed in an L-shape.
The tip of the claw is supported by a spring 7 so as to come into contact with the surface of the image carrier.

As shown in the figure, the tip of the full separation claw 6 is brought into contact with the tip toward the image carrier by an angle θ relative to the tangent at the point where the tip contacts the surface of the image carrier, thereby preventing damage to the image carrier. In order to avoid this as much as possible and achieve good separation, it is necessary to set the angle θ appropriately.

A portion near the other end of the holder 4 is connected to an engaging portion 4a on a shaft 2 rotatably supported at a proper position in the main body of the image forming apparatus.
The holder 4 is loosely fitted by the spring 8, and the holder 4 is given the ability to rotate in the counterclockwise direction in the drawing by a spring 8.
Rotation is prevented by making it come into contact with.

FIG. 5 is a diagram schematically showing a means for reciprocating the separating claw in the axial direction of the image carrier. A groove is formed in a direction inclined to the holder, and an engaging part 4a on the holder side is loosely fitted into this groove, and a dowel 4b (Fig. 4) formed on the inner surface of the groove is fitted loosely into the groove. It is a loose fit.

Therefore, when the shaft 2 is rotated via the gear 3 by a drive source (not shown), the holder 4 moves in the direction of arrow B in FIG. 5 due to the engagement between the inclined groove of the cam part 1 and the dowel on the holder side. , whereby the separation claw 6 attached to the holder 4
reciprocates in the axial direction of the image carrier 10.

With the above configuration, it is possible to prevent the separation claw from damaging the surface of the image carrier by staying at a specific position on the surface of the image carrier.8 However, in reality, the separation claw is not supported. As mentioned above, the separating mechanism has a combination of many parts, so it is difficult to bring the separating claw into contact with the surface of the image carrier accurately at a preset angle and manner. There is a risk that the carrier may be damaged or the tip of the separating claw may not come into contact with the image carrier, resulting in poor separation.

Although the device for reciprocating the separation claw has been described above, it is possible to use other means such as a solenoid.
In the case where the separation claw is brought into contact with the image carrier only when the transfer material reaches the separation position, the time during which the separation claw is in contact with the image carrier is shortened to prevent damage to the image carrier. However, there is basically no difference from the above case in terms of the difficulty of setting and maintaining the direction of the separating claws accurately.

The present invention has been made to deal with the above-mentioned situation, and as described above, in a separating device equipped with a separating claw that separates the transfer material by bringing its tip into contact with the image carrier, By providing means for setting and maintaining the direction of the separation claw, the contact angle of the separation claw with the surface of the image carrier can be maintained constant, and transfer material separation can be performed stably and reliably at all times. The purpose is to provide a device.

(2) Structure of the invention (technical means for solving the problem, its effect) In order to achieve the above object, the present invention provides a method for attaching separation claws to a rotating body such as an image carrier by abutting a separating claw on the rotating body such as an image carrier. A transfer material separation device of an image forming apparatus that separates sheet materials to be processed, wherein the separation claw is rotatably supported, and a gap holding member is provided to maintain a constant gap between the rotation center of the separation claw and the rotating body. It is characterized by:

With this configuration, regardless of the processing accuracy and assembly accuracy of the parts that make up the transfer material separation device, the relationship between the separation claws and the rotating body can be set well, and stable separation can be performed at all times. comes 8.

(Description of Examples) FIG. 1 is a side view of a separation device showing an embodiment of the present invention, which has basically the same configuration as that shown in the above-mentioned figures, and has corresponding parts. are shown with the same reference numerals, and their explanation will be omitted unless necessary.

The holder 4 is given the ability to rotate counterclockwise in the drawing by a spring 8, as in the above-mentioned device, and a roller 11 and a pawl support piece provided at the end of the holder 4 on the image carrier side are attached to the roller 11. Concentric separation claws 6 are provided.

The rollers 11 are brought into contact with the image carrier by the action of the spring 8 to ensure a separation ΔE between the center thereof and the surface of the image carrier, and thereby the separation claw 6 is brought into contact with the surface of the image carrier. maintaining the angle.

This will be explained with reference to FIG.

This figure is a perspective view showing only the part near the separation claw 6. A shaft 5a is pivotally attached to the claw support piece 5 attached to the holder 4, and the separation claw 6 is attached to this. Further, a roller 11 having an appropriate thickness ΔF is rotatably provided.

With this structure, the rollers 11 come into contact with the surface of the image carrier due to the action of the spring 8, thereby determining the position of the shaft 5a supporting the holder 4, and thus the separation claw 6, with respect to the image carrier. If the tip of the separation claw 6 is brought into contact with the surface of the image carrier by a spring (not shown), the diameter of the roller 11 is appropriately set to bring the tip of the separation claw into accurate contact with the surface of the image carrier. be able to.

In this case, the rollers 11 have an appropriate thickness, act to prevent the holder 4 from rotating, and rotate together with the image carrier, so that wear is extremely small (i.e., the wear on the image carrier at the tip of the separating claw is The position and angle are maintained unchanged over a long period of time, and a stable separation action can be performed at all times.

In the above case, one roller is provided for one separation claw, but as mentioned above, the holder 4 has
Since the image carrier is usually provided with a plurality of separation claws in the axial direction, the rollers 11 which are the abutment elements are arranged so that they come into contact with the non-image tilting walls near both ends of the image carrier itself. By arranging an appropriate number of separating claws on a long shaft that supports this roller,
Since the rollers do not come into contact with the image tilting wall, damage to the image tilting wall can be reliably avoided, and the degree of freedom in selecting the force of the spring 8 that biases the holder is increased, which is preferable.

Furthermore, the abutment rollers mentioned above do not need to be brought into direct contact with the surface of the image carrier (although they may be brought into contact with a member that has a certain relative position with respect to the image carrier). Of course, if this is done, there is no need for a rotating member such as a roller, and the design may become easier.

Furthermore, although the embodiments in which the present invention is applied to an image carrier have been described above, it will be easily understood that the present invention can also be applied to a fixing roller of a fixing device, a transfer drum, etc.

(3) As described in detail, according to the present invention, in a transfer material separation device equipped with a separation claw that separates a transfer material from an image carrier, the position and direction of the separation claw with respect to the image carrier can be easily adjusted. Moreover, it is possible to reliably set the separation appropriately, and to prevent the occurrence of separation defects, it is possible to perform stable separation of the transfer material at all times.

[Brief explanation of drawings]

FIG. 1 is a side view of the main parts of a transfer material separation device showing an embodiment of the present invention, FIG. 2 is an oblique view of the vicinity of the separating claw, FIG. FIG. 4 is a perspective view showing the structure of a holder portion that supports the separating claws. 2...Shaft, 4...Holder, 6...Separation claw, 7...
- Spring, 10... image carrier. Figure 3Figure 2

Claims (3)

[Claims] (1) In a transfer material separation device of an image forming apparatus in which a separation claw is brought into contact with a rotating body to separate a sheet material attached to the rotating body, the separation claw is rotatably supported, and the rotation center thereof is A transfer material separation device comprising a gap maintaining member that maintains a constant gap between the rotating body and the rotating body. (2) The transfer material separating device according to claim 1, wherein the gap maintaining member is a roller that contacts the rotating body and rotates about the rotation center of the separating claw. (3) The transfer material separating device according to claim 2, wherein the rotating roller is located outside the image area of the rotating body.