JPH0136199Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fixing device for an image forming apparatus that records images, such as an electrophotographic copying machine, a printing machine, a recording device, etc., and specifically relates to a fixing device having a recording material separation mechanism. .

Conventionally, a separation mechanism has been used in which a separation member such as a separation claw is pressed against or close to a rotating body such as a fixing roller. A fixing device in an electrophotographic copying machine having such a conventional separation mechanism is shown in FIGS. 1 to 3. To explain using this, 1 is a fixing roller made of a hollow pipe, 2 is a halogen lamp located in the middle of the fixing roller 1 and used to heat the fixing roller 1, and 3 is rotatable by a pressure means (not shown). The pressure roller 3 is in pressure contact with the fixing roller, and the pressure roller 3 is made up of a core metal 3a and silicone rubber 3b. 4 is a paper entry guide,
Reference numeral 5 denotes a separation claw, which is mounted on a claw mounting plate 6 so as to be rotatable about a fulcrum 5a, and is urged by a spring 7 so that the claw tip 5b comes into contact with the fixing roller 1 with a constant pressure. ing.

This separation claw 5 is provided to prevent recording material such as transfer paper from wrapping around the fixing roller 1, and the tip of this separation claw 5 separates the paper while being in pressure contact with the fixing roller 1. It is sharply formed by necessity.

8 is a paper ejection guide, 9 and 10 are paper ejection rollers, 11 is a bottom plate, 12 is a felt cleaning pad impregnated with silicone oil, 13
is a rotation support shaft of the mounting plate 6.

During operation, the transfer paper P with the toner image transferred thereon is sent between the fixing roller 1 and the pressure roller 3 while being guided by the paper entry guide 4 by the conveying means on the copying machine main body side. Here, the toner image on the transfer paper P is fixed by being heated while applying pressure by the fixing roller 1 and the pressure roller 3, and then guided by the paper ejection guide 8 and the separating claw 5, as shown in FIG. The paper is ejected to the outside of the machine by a paper ejection roller 9 and a paper ejection roller 10 that rotate in the direction of the middle arrow. Jams in the fixing device often occur between the fixing roller 1 and the paper ejection roller 9, and jam removal can be facilitated by releasing the separation claw 5 and part of the conveying means as shown in FIG. It can be carried out. During this jam processing, by rotating the claw mounting plate 6 of the separation claw around the spindle 13 (see Fig. 2), the paper ejection roller 10 rotatably attached to the claw mounting plate and the separation claw 5 are simultaneously operated. It has been canceled.

However, in such a case, as shown in FIG. 3, when the separation claw 5 is released and set, the tip 5b of the separation claw is subject to the tensile force of the spring 7 from the position shown by the solid line to the set position shown by the dashed line. Since the separating claw 5 moves in contact with the surface of the fixing roller 1, there is a risk that the tip of the separation claw 5, which has a sharp tip 5b, may damage the surface of the fixing roller 1 coated with resin such as Teflon. If the mounting plate 6 was closed too forcefully, the separation claw 5 and the fixing roller 1 would collide and cause damage. In order to prevent this, when resetting, the separation claw and the conveying section are supported by a spring, and when the separation claw comes into contact with the roller, the separation claw is set against the force of the spring, so that the separation claw suddenly collides with the roller. Methods have been considered to prevent this, but this method increases the number of parts such as springs, complicates the configuration, and may cause problems during set-up depending on how the center of rotation of the separation claw and conveyance section is positioned. There are drawbacks such as the distance traveled by the separation claw and the roller while being in contact with each other increases, and the separation effect becomes insufficient if force is applied and the separation claw is suddenly set.

In addition, when the separating claw is placed close to the surface of the fixing roller made of rubber or the like without contacting it, the same drawbacks as above are seen, and in addition, the problem is that the surface of the fixing roller is easily damaged and the fixing performance is reduced. There is.

It is an object of the present invention to eliminate the above-mentioned drawbacks, and to provide a fixing device with excellent operability that can prevent scratches on the surface of the rotating body due to contact with the separating member that occurs when the separating member moves with a simple structure. It is something. Another object of the present invention is to make it possible to improve the positional accuracy of the separation member with respect to a rotating body such as a fixing roller.

To achieve the above object, the present invention includes: a rotating body that fixes toner images on the recording material while nipping and conveying the recording material; and a plurality of separation members that separate the recording material by coming close to or in contact with the surface of the rotating body. A fixing device including an openable and closable cover member that covers a rotating body,
The plurality of separation members are integrally rotated by moving the support shaft in a direction away from the rotating body in response to the opening operation of the cover member. It is characterized by being moved in a direction away from the body.

Hereinafter, the present invention will be explained in detail based on the embodiment shown in FIGS. 4 to 8. However, the explanation of the structure of this embodiment that is the same as that described above will be omitted, and the features of this embodiment will be explained below. Mainly detailed.

Fig. 4 is a sectional view of the embodiment of the present invention, Fig. 5 is a side view on the same plane as Fig. 4, Fig. 6 is an explanatory diagram of the opening operation of Fig. 4, and Fig. 7 is a side view of Fig. 6. 8 is a perspective view of FIG. 4.

The fixing device in each figure is detachably supported by a known guide means or the like to the main body of an image forming apparatus such as a copying machine, and is held at a desired position within the apparatus in the state shown in the figure.

Reference numeral 6 denotes the above-mentioned claw mounting plate that serves as an upper cover plate of the fixing device main body, and is located above the fixing roller 1 as the first rotating body, and is attached to the rotation center axis B at a predetermined position on the side plate 15 of the fixing device. It is held rotatably. In this embodiment, the rotation center axis B is set to the side plate 1.
5, but it may of course be provided integrally with the pawl mounting plate so that the shaft B engages with a predetermined position on the side plate 15.

This claw mounting plate 6 is a variable pressure plate 6 ₁ having a pin 6 ₂
have. On the other hand, the pressure plate 20 is held by a fixed shaft 19 and is supported by a pressure roller 3 by a pressure spring 18.
A variable pressure auxiliary plate 17 is provided on the opposite side of the fixed shaft 19 so as to correspond to the variable pressure plate 6 ₁ . The variable pressure plate 6 ₁ and the variable pressure auxiliary plate 17 are of a mechanism that varies the pressure contact state between the fixing roller 1 and the pressure roller 3 in conjunction with the claw mounting plate 6 . The variable pressure auxiliary plate 17 engages with a protrusion 17 ₁ that guides a pin 6 ₂ and can move downward together with the plate 17 by the pin 6 ₂ , and a pin 6 ₂ to prevent rotation of the claw mounting plate 6. It has a groove ₁₇₂ for temporarily stopping and holding it. Note that the pin ₆₂ may be a projection or a spherical surface as long as it is of a type that slides on the auxiliary plate 17.

Further, a holding plate 6a for holding the separation claw 5 is provided at the lower part of the claw mounting plate 6. This holding plate 6a has an elongated hole 6b that holds the support shaft 14 of the separating claw 5 in a movable manner (FIG. 4). Both ends of the support shaft 14 are held in the elongated holes 6b, and the tip end thereof enters a guide groove 16, which is usually a notch in the side plate 15, and is engaged and held by a locking part 16a of the guide groove 16. Ru. The guide groove 16 further includes a guide protrusion 1 above the locking part 16a with respect to the opening direction of the claw mounting plate 6.
6b. This guide protrusion 16b forms the guide groove 16 itself into a dogleg shape, and the locking portion 1
To ensure stable holding of the support shaft 14 to 6a. This guide groove 16 may have any shape, but the support shaft 1
4 is preferably molded so that it is slidably guided, and it is also preferable to provide a guide surface ₁₆₁ that matches the diameter of the support shaft 14 so that the support shaft 14 does not vibrate greatly (FIG. 5).

Now, when it is necessary to open the fixing section for jamming or maintenance inspection, etc., the claw mounting plate 6 is moved upward as shown in FIG. 6 to perform the opening operation. Then, the separation claw 5 is reliably separated from the surface of the fixing roller 1. This is because the support shaft 14 is in the elongated hole 6b.
This is achieved by moving from a position at the end of the fixing roller 1 side to the other end of the elongated hole 6b by being urged in a direction away from the fixing roller surface 1 side by the guide protrusion 16b of the guide groove 16. be done. In this embodiment, the support shaft 14 moves upward along the guide groove 16 while being guided by the guide protrusion 16b, so that it moves away from the fixing roller 1, and as a result, the tip of the separating claw 5 has a shaft 14 that is guided by the guide protrusion 16b. When it reaches , it moves largely in the direction of vector C and moves away from the surface of roller 1. Incidentally, in this manner, the tip of the separation claw 5 moves along the trajectory E. In this manner, in this embodiment, the paper ejection roller 10 is supported so as to move together with the claw mounting plate 6, so that a large space for jam processing can be formed. Conversely, even when setting the separation claw 5, the support shaft 14 is reliably guided by the guide groove 16, so that the tip of the separation claw 5 comes into contact with the surface of the fixing roller 1 last. Therefore, even if the separating claw is moved together with a claw mounting plate such as an opening/closing plate, the surface of the roller 1 will not be damaged.

Further, it is preferable to form a curved surface near the locking portion 16a of the guide groove 16 to prevent sudden movement of the support shaft. Even if the separating claw acts, scratches on the surface of the fixing roller 1 due to the separating claw can be prevented.

Further, in this case, the above-mentioned pressure variable mechanism is also used in this embodiment. That is, the relative positional relationship between the pressure roller 3 and the fixing roller 1 changes as well as the relationship between the separation claw 5 and the fixing roller 1 according to the opening/closing operation of the claw mounting plate 6.

To explain its function, when pressurizing, the pressure variable plate 6 ₁ ,
Although the pressure variable auxiliary plate 17 is in a non-contact state (light pressure or contact may be used, a non-contact state is preferable in consideration of durability and wear resistance). When the plate 6 is opened upward, the pin 6 ₂ is guided by the gentle slope of the guide protrusion 17 ₁ of the variable pressure auxiliary plate 17 and reaches above the guide protrusion 17 ₁ .
Here, the pressing state between the fixing roller 1 and the pressure roller 3 is either light contact or a state where they are separated. Accordingly, the separation claw can be moved relative to the fixing roller 1 (or pressure roller or pressure fixing roller) by moving away from (or approaching or contacting) and releasing the pressure (or varying the pressure) depending on the claw mounting plate 6.

In addition, this embodiment is further provided with a safety mechanism that is simpler and cheaper than the conventional one in order to make operations easier when the claw mounting plate 6 is open, or to maintain safety and hygiene. This example is the groove 17 ₂ in which the pin 6 ₂ described above is locked. In other words, a further feature of this embodiment is that, in accordance with the opening/closing operation of the claw mounting plate 6, the separation claw can be moved toward and away from the roller surface, pressurized/released (or pressure variable), and the safety mechanism can be performed as a series of steps. be. To explain this safety mechanism based on an example (see Fig. 7), the pin ₆₂ presses the variable pressure auxiliary plate 17 and changes the relative positions of the rollers 1 and 3 due to the above-mentioned action. Groove 17
₂ . At this point, the operator stops moving the claw mounting plate 6, and even if the operator releases the claw mounting plate 6, the rotating roller ₆₂ is locked in the groove ₁₇₂ , so the claw mounting plate remains open at the desired position. Fixed. Therefore, since the operator can see inside the apparatus, he can easily perform jam removal, etc.
After processing, the operator moves the claw mounting plate 6 downward to ensure a pressurized state between the rollers 1 and 3, and the separation claw 5 is installed in a fixed position.

Incidentally, if the configuration of the above embodiment is supplemented, the separation claw 5 is rotatably supported on the support shaft 14.
Further, the separation claws 5 are small pieces as shown in FIG. 8, and are arranged in several pieces (not shown) in the axial direction of the roller. However, the separation claws of the present invention include separation members such as a plurality of such separation claws and scrapers. The support shaft 14 is always biased in the direction of arrow A by a biasing means such as a leaf spring (not shown) attached to the claw mounting plate 6 (for reference, see the spring 21 in FIG. 8). The upper part of the separating claw 5 passes through the hole 6c of the claw mounting plate 6 and engages with a spring 7 on the opposite side which brings the tip of the claw into contact with the roller surface.

The above-described embodiments relate to heat-fixing rollers with built-in heating means, but the present invention is most suitable for fixing rollers, pressure rollers, or pressure-fixing rollers that have resin or rubber surfaces, and can be separated. It can be applied to a rotating body for fixing where scratches may occur due to contact with claws or separation members.

As described above, the separating member is moved integrally with the openable/closable member located above the fixing rotary body, such as the cover of the fixing device itself, the cover member of the image forming apparatus main body, or the heat insulating plate of the fixing device, Furthermore, by guiding the support means such as the support shaft of the separating member in a direction away from the rotating body, separation of the separating member from the fixing rotating body is ensured, and the relative position of the separating member with the fixing rotating body is controlled. The accuracy can be increased. In addition, since the separation member has a support means that supports the separation member so that it can be moved relative to the movement of the member that can be opened and closed, the space required for movement of the separation member can be reduced, and the fixing device itself can be made smaller. can.

As described above, according to the present invention, it is possible to prevent scratches on the surface of the fixing rotor when attaching and detaching the separation member with a very simple configuration, and to provide a fixing device that is easy to jam and has excellent operability. can be provided.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of a conventional fixing device,
FIGS. 4 to 8 are explanatory diagrams for explaining embodiments of the present invention, respectively. 1 is a fixing roller, 2 is a halogen lamp, 3 is a pressure roller, 5 is a separating claw, 6 is a claw mounting plate, 6a is a holding plate, 6b is an elongated hole, 6 ₁ is a variable pressure plate, 6 ₂ is a pin,
7 is a spring, 9 and 10 are paper discharge rollers, 14 is a support shaft, 15 is a side plate, 16 is a guide groove, 16a is a locking portion, 16b is a guide protrusion, 16 ₁ is a guide surface, 17
is a pressure variable auxiliary plate, 17 ₁ is a protrusion, and 17 ₂ is a groove.

Claims (1)

[Claims for Utility Model Registration] A rotating body that fixes toner images on the recording material while nipping and conveying the recording material, a plurality of separating members that separate the recording material by coming close to or in contact with the surface of the rotating body, and A fixing device having an openable and closable cover member that covers the body, the fixing device having a support shaft that supports the plurality of separation members,
The fixing device is characterized in that, in response to the opening operation of the cover member, the support shaft is moved in a direction away from the rotating body, thereby moving the plurality of separation members integrally in a direction away from the rotating body. Device.