JPH0646336B2 - Fixing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fixing device in an electrophotographic apparatus such as a copying machine.

(Prior Art) A latent image formed on an image carrier such as a photosensitive drum by irradiating light information corresponding to a subject on the image carrier is converted into a toner image in a developing process, and the toner image is converted into a toner image. The transfer material, which has been transferred onto a transfer material such as paper or resin film by a corona discharger and has a toner image formed thereon, is separated from the image carrier and introduced into a fixing device by a guide plate or the like, where the toner image is fixed. . This fixing device includes a fixing roller having a built-in heater or a heater arranged in proximity to the peripheral surface, and a pressure device such as a roller or an endless belt device for fixing a toner image by nip-conveying a transfer material between the fixing roller and the fixing roller, And related members such as a peeling pawl and a paper discharge roller that are operably arranged around and around these members.

In the conventional structure, such a fixing device is directly mounted in the main body of the electrophotographic apparatus or is incorporated in the main body as one unit.

(Problems to be Solved by the Invention) In a conventional fixing device, when a transfer material such as paper is clogged in the device, that is, a jam state occurs, it is difficult to remove the clogged transfer material. There was a problem. In addition, considerable manual work was required when replacing or inspecting or repairing the members, or when replacing the offset prevention oil. Further, in the case where the endless belt device is used as the pressure device for the fixing roller, since the time for pressing the transfer material, that is, the contact time of the endless belt with the fixing roller is relatively long, the temperature and the pressure can be relatively low. However, the pressure of the endless belt against the fixing roller is likely to be non-uniform, so that there is a drawback that a defective fixing portion is likely to occur.

An object of the present invention is to solve the above-mentioned problems of the prior art. Therefore, it is preferable in terms of performance, and facilitates removal of a clogged transfer material, and facilitates replacement and repair of members. The present invention is to provide a fixing device.

(Means for Solving Problems) A feature of the present invention is to provide an endless belt device that includes a support body slidably provided with respect to a fixing device main body, has a fixing roller installed on the main body side, and presses against the fixing roller. Therefore, the endless belt device comprises a support plate swingably installed on the support and a pair of support plates supported by the support plate and located on both sides of the fixing roller. The support roller including a support roller and an endless belt hung between the support rollers, and the support roller located on the side opposite to the sliding direction passes through the end of the fixing roller on the side in pressure contact with the endless belt. The endless belt is positioned so as to project to the fixing roller side beyond a tangent line parallel to the direction, and is urged so that the endless belt is pressed against the fixing roller.

(Operation of the Means) Since the fixing device can be removed from the main body by sliding the supporting member, when the transfer material such as paper stops inside and causes a jam, the supporting member can be removed. The endless belt device is also removed from the fixing roller, and the transfer material jammed between them is very easily removed. Further, since the endless belt device can be easily detached from the main body of the electrophotographic apparatus, each member can be easily handled. Further, the endless belt is swingable and is pressed against the fixing roller by the elastic force of the spring, so that it does not receive an excessive force.

(Example) Next, an example of the present invention will be described with reference to the drawings. 1 to 3 show a preferred embodiment of the present invention, in which (1) is a fixing roller,
The fixing roller (1) is provided with an endless belt device (2) as a pressure device that sandwiches a transfer material, for example, paper, and presses it. The fixing roller (1) is usually a hollow Al roller whose surface is coated with an offset preventing material such as tetrafluoroethylene resin, and a rod-shaped heater is arranged in the hollow. Endless belt device (2) is endless belt device (2a)
And a plurality of rollers for hanging it, a pair of rollers (3) in the illustrated embodiment. The belt (2a) is in pressure contact with the fixing roller (1) between the pair of rollers to increase the contact area with the fixing roller (1). (5a) is a pair of rollers (3).
It is a support shaft of a support plate (5) that supports (4). Normally, the fixing roller (1) is rotated by a motor, but the endless belt device (2)
Operates by contact with the fixing roller (1), ie by friction transmission.

This fixing device includes a side plate (7) as a support body slidably provided on both side plates (6) of the main body side, and the fixing roller (1) is integrally fixed to the side plate (6). The endless belt device (2) is installed on the side plate (7). Further, the side plate (6) has an appropriate number of stoppers for positioning, and in the example shown, a pair of stoppers (8
a) and (8b) are fixed, and the other side plate (7) has fitting portions (9a) and (9b) for receiving those stoppers. The side plates are formed by engaging the stoppers with the fitting parts.
(7) is installed at a predetermined position with respect to the side plate (6).

In this embodiment, each stopper (8a), (8a) is provided on the side plate (6) on the main body side, but if desired, the stopper is provided on the side plate (7), and a fitting portion for it is provided on the side plate (7). It may be provided on the side plate (6). In the illustrated example, the support is a fixing roller (1)
Is configured to be slidable in a direction substantially perpendicular to the axis of
Therefore, as shown in FIG. 6, a slide rail (10) such as Acculide (trade name) is provided between the fixed side plate (6) and the movable side plate (7). The slide rails shown are the fixed slide rail (10a), the movable slide rail (10b), and the intermediate slide rails inside them.
It consists of (10c) and spheres (10d) placed in rows between them. Such a sliding mechanism may be any such as a guide member of any suitable form.

Further, this device is provided with a clamp device (12) for locking the side plate (7) supporting the endless belt device (2) at a predetermined position with respect to the side plate (6) on the main body side. The side plate (7) can slide by releasing the locking. An example of the clamp device (12) is shown in FIG. 10, but there are various conventional clamp devices of this type, and any one of them can be used. First
The clamp device shown in FIG. 0 includes a lever member (12b) pivotally fixed to a fulcrum shaft (12a) on a side plate (7), and the lever member includes an interlocking shaft (12d) provided with a handle (12c). A spring (12e) is mounted and there is a recess (12f). (12g) is a stopper. (1
Reference numeral 2h) is a fixed shaft provided on the side plate (6), which is locked when the recess (12f) of the lever member is fitted into the fixed shaft (12h) as shown in FIG. 10 (a). As shown in FIG. 10 (b), when the handle (12c) is rotated, the lock is released, and the side plate (7) can be slid.

In addition to the above members, a fixing device to which the present invention relates, as shown in FIG. 1, a guide for guiding a transfer material such as paper separated from an image carrier (not shown) to a fixing roller (1). Board (1
3), a peeling claw (14) that comes into contact with the surface of the fixing roller (1) to prevent paper wrapping, a container (16) containing an oil (15) for offset prevention such as silicone oil, and fixing the oil An oil application device (17) such as felt for supplying to the roller (1), a cleaning which extends along the axial direction of the fixing roller (1) and which has a rubber blade fixed to the tip of an elastic plate such as phosphor blue steel. A temperature detector (19) for detecting the temperature of the surface of the blade (18) and the surface of the fixing roller (1) and controlling ON / OFF of the heater via an appropriate electric circuit is provided.

Further, in order to convey the paper after fixing and discharge it to a tray or the like, a transfer material peeling member (2) made of a resin such as polyimide whose tip is pressed against the surface of the endless belt (2a) by its own elasticity
0), a pair of paper discharge rollers (21), (22), a transfer material guide plate (23) for guiding the paper to the paper discharge rollers, and an actuator (24) for detecting the transfer material after fixing are provided. Although omitted, a sensor or actuator that detects the transfer material before fixing is on the feeding side to the fixing roller (1), and the actuator on the exit side after a certain time after detecting the paper on the feeding side. (twenty four)
If it is not detected by, the heater is automatically de-energized to prevent blackening of the paper. The fixing roller (25) in FIG.
Reference numeral 26 is a terminal contact for energizing the heater in (1), and reference numeral (26) is a gear which is driven by a motor and interlocks with the fixing roller (1) to rotate it.

As described above, the rollers (3) and (4) of the endless belt device (2) as the pressurizing device are pivotally stopped by the support shaft (5a), and thus the endless belt device (2) is It is configured to be swingable around a support shaft (5a). Then, a spring is provided at an appropriate position of the support member (5), for example, between the shaft (27) of one roller and the pin (28) fixed to the side plate (7) as shown in FIGS. (29) is installed, the support member (5) by the action of the restriction window (7a) formed on the shaft (27) of the rollers (3) and (4) and the side plate (7).
The rocking range is regulated, and the endless belt (2a) is pressed against the surface of the fixing roller (1) by the spring force of the spring (29). Usually the spring (29) is mounted on the outside of the side plate (7). The endless belt device (2a) is made of a heat resistant material such as silicon rubber, and preferably made of a material having appropriate elasticity. Rollers (3), (4) for hanging endless belts
Usually consists of Al rollers.

In the illustrated embodiment, the support shaft (5a) is provided in the middle of the rollers (3) and (4), but it may be provided at another position of the support member (5), for example, one roller. The shaft (27) of (3) may be used as a support shaft and the spring (29) may be attached at another position.

Preferably, as shown in FIG. 3, the outer peripheral portion of the fixing roller (1) comes into contact with the endless belt device (2a) on the side closer thereto, but a part of the fixing roller (1) is one roller (4). Upper belt
It projects beyond the tangent line (a) on the side close to the fixing roller (1) parallel to the sliding direction (shown by the arrow (30) in FIG. 4) from the surface (2a). That is, the support roller (4) located on the opposite side to the sliding direction
Is located so as to project to the fixing roller side beyond a tangent line (b) parallel to the sliding direction that passes through the end portion (1a) of the fixing roller (1) that is in pressure contact with the endless belt device (2a). With such a structure, the structure can be made compact and the pressurization by the endless belt device (2) can be suitably performed.

In addition, if desired, a roller for hanging the endless belt (2a)
A heater is also inserted in (3) and (4), which causes the belt (2
It is also possible to heat the back side of the paper via a). In this case, since the heater on the endless belt side simply heats the paper, a heater that heats weaker than the heater in the fixing roller (1) is used. Further, the heater for heating the fixing roller (1) does not necessarily have to be built in the roller, and may be arranged close to the outer peripheral surface of the roller to heat the roller.

During operation, the paper on which the toner image is formed by the photosensitive drum is introduced between the fixing roller (1) and the endless belt (2a) through the guide plate (13), and the toner image is fixed by passing between them. The peeling claw (14) separates the fixing roller (1) from the winding, and the peeling member (20) separates the belt (2
Adhesion to a) is also prevented, and the paper is ejected by the paper ejection rollers (21) and (22) through the guide plate (23), which is detected by the actuator (24).

If the paper stops while being sandwiched between the fixing roller (1) and the endless belt (2a), the clamp device (12) is unlocked to remove the jammed paper, and the side plate (7 ) To separate the endless belt device (2) from the fixing roller (1). In that case, as shown in FIG. 4, attach the side plate (7) to the arrow (30).
When the roller (4) slides across the belt (2a) and abuts against the fixing roller (1), the roller (4) moves along with the support member (5) against the elasticity of the spring (29). ) Is slightly rotated in the direction of the arrow (31), so that the position can be exceeded.
When the roller (4) moves beyond the position of the fixing roller (1), the elastic force of the spring (29) causes the opposite direction (32) as shown in FIG.
It turns to and is pulled out and removed from the main body.

As a preferable mode, as shown in FIG. 7, the fixing roller (1) has a cross-section inverted crown shape in which the central portion (11c) has the smallest diameter and gradually increases toward both ends, and the endless belt ( The pair of rollers (3) and (4) on which 2a) is applied has a crown-shaped cross section in which the central portions (3c) and (4c) have the maximum diameter and the diameter gradually decreases toward both ends. With such a configuration, the meandering of the belt can be prevented more effectively.

In addition, as a preferable form of the sensor portion related to the actuator (24), as shown in FIG. 8, a magnet (35) attached to an arm (34) fixed to the actuator shaft (33), It is composed of a magnetic sensitive switch (36) sensitive to it.

FIG. 9 shows a state in which the fixing roller (1) is removed from the side plate (11) of the main body. As shown in FIG. 9, the side plate (11) usually has a cutout ( 38) The shaft part (39) of the fixing roller (1) is installed, and the drive gear (26) is screwed.
The bearing (37) is attached to the shaft portion (39) by the (40) and to the notch portion (38) of the side plate (11) by the screw (41). Therefore, when the endless belt device (2) is removed from the fixing roller (1), the fixing roller (1) can be easily removed. Further, when the endless belt device (2) is removed, other members can be easily handled.

Further, as shown in FIG. 1, preferably, the side plate (7) slidable on the main body is provided with a peeling claw (1) related to carrying out the paper after fixing.
Members such as 4) and paper discharge rollers (21) and (22) are attached, and if desired, offset preventing oil (15) and its coating device (17) are also attached to the side plate (7). With such a configuration, handling such as inspection and replacement of these members becomes easier.

In the above embodiment, the endless belt (2a) is a pair of rollers (3),
Although it is hung on (4), it may be hung on three or more rollers in some cases. In addition, the endless belt was driven by frictional contact with the fixing roller. (4) A transmission gear may be fixed to one or both of them, and the gear may be engaged with the gear (26) when the support is mounted to obtain a driving force.

(Effects of the Invention) As described above, according to the present invention, the endless belt device is detached from the fixing roller by the sliding movement of the support member, so that the transfer material jammed between them can be removed very easily. In addition, by removing the pressure device, each member constituting the fixing device can be easily handled, and their replacement, inspection, and repair can be easily performed. Further, since the endless belt device as a pressurizing device is swingable and presses against the fixing roller by the force of the spring, it is possible to avoid an unreasonable force. Therefore, the pressing force against the fixing roller becomes uniform, so that fixing failure occurs. Absent.

[Brief description of drawings]

FIG. 1 is an elevational view showing the internal structure of a fixing device according to an example of the present invention, FIG. 2 is a partial perspective view thereof, FIG. 3 is a side view thereof, and FIG. FIG. 7 is a side view showing a state where the supporting body of the apparatus is slightly slid, FIG. 5 is a side view showing a state where the supporting body is further slid, and FIG. 6 is an elevation view showing an example of a sliding mechanism. Is a perspective view of a fixing roller of the preferred embodiment and a pair of rollers for applying a pressure belt, FIG. 8 is a perspective view of an example of a transfer material sensing system, and FIG. 9 is an exploded view showing a state in which the fixing roller is removed. FIG. 10 is a perspective view and FIG. 10 is a side view showing an example of the clamp device. In the figure, 1 ... Fixing roller, 2 ... Endless belt device, 6 ...
… Main body, 7 …… Support, 8a, 8b …… Stoppers, 9a, 9b…
… Fitting part, 12 …… Clamp device, 5 …… Support plate for endless belt device, 5a …… Support shaft, 27 …… Roller shaft, 28 ……
Pin 29 ... spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Takigawa 4-21-3 Shimomaruko, Ota-ku, Tokyo Inside the Shimomaruko factory, Katsurakawa Electric Co., Ltd. (56) Reference JP-A-58-194073 (JP, A) Sho 48-25748 (JP, U) Actually opened Sho 55-97763 (JP, U)

Claims (1)

[Claims] 1. A fixing device including a fixing roller heated by a heater and an endless belt device for sandwiching and conveying a transfer material on which a toner image is formed, to the fixing roller, wherein the endless belt device is the fixing roller. A support plate slidably mounted on a support body slidably provided with respect to the main body on which the main body is installed, and a pair of support rollers supported by the support plate and located on both sides of the fixing roller; An endless belt hung between support rollers, wherein the support roller located on the opposite side to the sliding direction is parallel to the sliding direction passing through the end of the fixing roller on the side in pressure contact with the endless belt. A fixing device, which is positioned so as to project beyond the tangent line toward the fixing roller and is biased so that the endless belt is in pressure contact with the fixing roller.