JPS63130948A - Driving motion releasing device - Google Patents

Abstract

PURPOSE:To lightly disconnect a driven member etc., at any position in the captioned device for an electrostatic copying machine, by reversing the turning direction of a driving motor immediately before the driving system stops, so that the engagement of the transmitting system such as gear, etc., can be dis engaged after the system has once been slackened. CONSTITUTION:On the transfer paper discharge side of a fixing device, a lid 10b is arranged in such a manner than the lid 10b can freely be rotated or closed/opened by a pin 10c. In the neighborhood of the pin 10c, a lever 8, which is pivotally mounted by a pin 8b, is arranged. A spring 9 is suspended between one end 8b of the lever 8 and the pin 11 installed to the lid 10b, so that the lever 8 is in the habit of rotating clockwise. Thus, a projected part 10d that is formed on the lid 10b serves as a stopper. When the system is stopped by jamming or the like, the turning direction of a driving motor is reversed a little immediately before the driving motor stops. Accordingly, a spring 9 is elongated, thereby rotating the lever clockwise. Thus, the engagement between a gear 2 and a gear 4 can easily be disengaged. As a result, the transfer paper can easily be taken out by hand.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention is particularly suitable for use in image forming apparatuses that utilize an electrostatic recording process, such as electrostatic copying machines and printers. This invention relates to a drive release device for a driven member or unit.

(Prior art and problems to be solved) For example, as seen in a fixing device of an image forming apparatus, a transfer material carrying a toner image is passed between a pair of rollers that are in pressure contact with each other, and at this time, the transfer material is transferred by the pair of rollers. In a well-known fixing device configured to fix a toner image on a transfer material by applying pressure or pressure and heat to the material, if the transfer material jams while being held between a pair of rollers, the roller pair is A system has already been proposed in which the jammed transfer material is removed by temporarily separating it from the system and manually rotating the roller.

In other words, the rollers in the fixing device are driven by gears, tin rockets, etc. from the drive source in the image forming device, so even if each part of the device is stopped due to a jam, the fixing device will continue to work. This is because it is practically impossible to manually rotate only the rollers for use.

FIG. 3 shows an example of such a device, and its structure and operation will be briefly described next.

In the figure, reference numeral 10 denotes a fixing device that houses a pair of pressure rollers, a member for introducing a transfer material carrying a toner image at an image forming position (not shown), a member for discharging the fixed transfer material, etc. In the figure, only the roller 10a of the roller pair connected to the external drive system is shown, and other members are omitted.

The shaft of the roller 10a protrudes from the casing of the fixing device, and the gear 1 is attached to it.

This gear 1 meshes with a gear 4 supported by a holding member 3 that swings about a shaft 5a via an intermediate gear 2, and the gear 4 meshes with a gear 5 attached to the shaft 5a. ing.

Since the shaft 5a is connected to a drive system of an image forming apparatus (not shown), the torque of the shaft 5a is transmitted to the gears 5, 4. Same 2,
1, the constant force roller 10a rotates to perform the fixing action.

When the transfer material is jammed between the pair of rollers, rotate the lid 10b disposed on the fixing device in the direction of the arrow in the figure and bring it to the position indicated by the two-dot chain line. The attached lever 7 rotates from the position shown by the solid line to the position shown by the two-dot chain line, and the end 7b of the lever 7 comes into contact with the arm 6, which is also pivotally connected to the main body with a pin 6a, and the end 6
b swings the above-mentioned holding member 3 from the solid line position to the two-dot chain line position, the gear 3 and gear 2 are disengaged, and the fixing roller 10a is manually rotated freely from the outside. It is possible to jam and eject the transfer material.

However, as a practical matter, when the drive is stopped, the drive load of the fixing device is large, so each gear stops in a strongly engaged state, and furthermore, due to the inertial load of the motor and other parts that are the drive source when the drive is stopped, , the gear on the main body side and the gear on the fixing device side mesh tightly, and first of all, in this type of device, in order to stably transmit the driving force, the gear on the main body side that should be disengaged is connected to the fixing roller side. Usually, the gears are constructed so that they can bite into each other to prevent them from separating due to the reaction force of There is.

Once such a state occurs, the means for separating the gears, the arm 6 in the above example, becomes deformed and becomes inoperable thereafter, or the gears are damaged, resulting in significant inconvenience. If an attempt is made to avoid such a situation, each member will become larger, leading to an increase in cost, which is undesirable.

The present invention was made to deal with such a situation, and regardless of the state of the drive system when the device is stopped,
It is an object of the present invention to provide a fixing device that can operate stably without applying a particular load, deformation, or damage to each part.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention provides a method for stopping the drive source when removing a driven member or unit in an image forming apparatus from the drive source. This is characterized in that the motor serving as the drive source is configured to rotate slightly in the opposite direction at the immediately preceding point.

With this configuration, the meshing of all transmission systems can be forcibly loosened, so that driven members etc. can be easily and easily separated at any position.

(Description of an Embodiment) FIG. 1 shows an embodiment in which the present invention is applied to a fixing device of a copying machine.As is well known, the fixing device 10 includes a fixing roller 10a and a fixing roller 10a in pressure contact with each other. , a pressure roller that comes into pressure contact with the pressure roller, a member that introduces the transfer material into the pressure contact portion of both rollers,
It is assumed that members required for fixing, such as a member (both not shown) for discharging the transfer material after fixing, are provided.

A drive gear 1 is attached to the shaft of the fixing roller, and this gear 1 is mounted on a holding member 3 swingably disposed on a shaft 5a driven by a drive source of the image forming apparatus. A gear 4 that meshes with the gear 5 attached to the shaft 5a. intermediate gear 2
shall be driven through.

The structure and operation of this device are basically the same as those shown in FIG. 3, so a description thereof will be omitted.

A lid body 10b is provided on the transfer material discharge port side of the fixing device, and a pin lo
A lever 8 pivotally mounted by a pin 8b is provided near the lower end of the fixing device main body, near the pin lOc, and one end of the lever 8 A spring 9 is suspended between the pin 11 arranged on the lid tob and the lever 8 to give the lever 8 the ability to rotate clockwise in the figure, and a protrusion 10d formed on the lid.
serves as a stopper, causing the other end 8A of the lever to take a position close to the holding member 3.

Furthermore, in this image forming apparatus, when the apparatus is stopped due to a jam or the like, the drive motor is rotated slightly in the reverse direction immediately before the drive motor is stopped.

With this structure, when a jam occurs and the apparatus is stopped, when the lid 10b is rotated and opened in the direction of the arrow, the lever 8 is rotated clockwise in the figure while the spring 9 is extended. The end portion 8a displaces the holding member 3 to the position indicated by the two-dot chain line, but by this time, the meshing of each gear included in the drive system has loosened due to the reversal of the motor, so the engagement between gears 2 and 4 has loosened. The fixing roller can be easily rotated manually, and the transfer material can also be easily discharged.

FIG. 2 shows another embodiment in which the present invention is applied to a fixing device, which includes a fixing roller 10a, a gear 1
The structure up to the drive shaft 5a is the same as the above-mentioned device.

In the closed state shown by the solid line in the figure, the pin 12 of the fixing device main body
One leg 12 of a trifurcated release member 12 pivotally connected to a
The other end of the spring 13, which has one end locked to the main body side, is locked to the spring 13 to bias the member clockwise. When engaged, the release member 12 is maintained at the normal position value.

When the release member is in this position, the other leg end 12b is located close to the holding member 3.

With this structure, when the apparatus is stopped due to a jam occurring in the fixing section, when the lid body 10b is opened in the direction of the arrow, the pin lof acting as a lof is released from the leg of the release member. , the member rotates clockwise under the action of the spring 13, and the end 12b presses against the holding member.

In the case of this device as well, the drive motor rotates slightly in the reverse direction just before it stops to release the strong engagement of each gear, as in the case of the above-mentioned device, so the pressing action of the release member end 12b causes the gear 4 to easily disengages from gear 2, allowing manual operation of the fixing roller.

The present invention is applied to a fixing device of an image forming apparatus, and the gear train is displaced within a plane containing the gear train by the operator's operation of opening the lid on the ejection side. It goes without saying that the device is not limited to such a device, and as a means for displacing the portion corresponding to the holding member 3, a collar, knob, etc. for that purpose may be provided separately, or a means for displacing the portion corresponding to the holding member 3 may be provided, or it may be necessary to displace the portion corresponding to the holding member 3. It is also possible to perform this by using a solenoid, motor, etc.

Further, the disengagement of the gears may also be configured such that one of the gears is displaced in the axial direction.

Furthermore, it is easy to understand that the present invention is applicable not only to the fixing device but also to the engagement and disengagement of gear trains in various driven units branched by the main drive motor of one image forming apparatus. Dew.

(3) Effects of the Invention As explained above, the present invention is particularly strong because, when the device is stopped due to a jam or the like, the drive motor is reversed to loosen and disengage the gears and other transmission systems. The drive release function can be reliably performed over a long period of time without requiring a large-sized configuration.

[Brief explanation of the drawing]

FIG. 1 is a side view of a main part showing an embodiment in which the present invention is applied to a fixing device of a copying machine, FIG. 2 is a side view of a main part showing another embodiment of the same as above, and FIG. 3 is a drive of a known fixing device. It is a side view which illustrates a release means. l, 2.4.5. ...Gear, 3...Fist holding member, 8@
... Lever, 9.13... Spring, lO... Φ Fixing device body, 12. Φ Release member. /D Figure 3

Claims (1)

[Claims] A drive release device comprising a drive system and a member driven by the drive system, and for separating the driven member from the drive system after stopping the drive system, characterized in that the drive release device is reversed immediately before the drive system is stopped. drive release device.