JPH0475505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic apparatus that forms an image on a recording medium.

[Problems to be solved by conventional technology and invention]

The drive system of a conventional electrophotographic apparatus that can be divided into upper and lower halves will be explained with reference to FIG. The arrow indicates the direction of rotation of the gear. The electrophotographic device 1 is
It is divided into upper and lower parts by the AA line, and the upper unit 1a and lower unit 1b are pivotally connected by an opening/closing hinge 17 on the paper feed side of the electrophotographic apparatus 1, and the upper unit 1a is rotated clockwise. It is designed to open. A gear 2a fixed to the shaft of a drive motor 2 at the right end of the upper unit 1a transmits rotational force almost horizontally to the left through a gear system of intermediate gears 3 and 4 to a gear 5 coaxial with the photosensitive drum. Lower unit 1 via gear system of gears 6 and 7
The rotational force is transmitted to gears 12 and 13 coaxial with the fixing roller through a gear system of intermediate gears 8 and 9 (b). Further, the gear 12, which is coaxial with the fixing roller of the fixing device, passes through the gear system of the intermediate gear 14, and then the gear 1, which is coaxial with the paper ejection roller.
The rotational force is transmitted to 5. Also, the rotational force is transmitted from the intermediate gear 4 to the gear 23 coaxial with the paper feed roller via the gear system 20, 21, 22, through gears 18, 19 coaxial with the register roller.

The intermediate gears 8 and 9 are supported by a support frame 10 rotatably supported by a shaft 9a of the intermediate gear 9 so that the intermediate gear 8 and the intermediate gear 9 mesh with each other. The support frame 10 is engaged with a tension spring 11 that is engaged with the lower unit, and is biased counterclockwise.

When restoring the state shown in FIG. 1 from the state in which the upper unit 1a and lower unit 1b are divided into two parts around the opening/closing hinge 17 as shown in FIG. 2, the tips of the intermediate gears 7 and 8 collide with each other. The tooth tips of the intermediate gear 7 push the intermediate gear 8 against the bias of the tension spring 11 and rotate the supporting frame 10 clockwise to prevent damage to the intermediate gears 7 and 8. When the tooth tips of the intermediate gear 7 rotate due to the rotation transmitted from the drive motor 2, the intermediate gears 7 and 8 mesh, and the tension spring 1
1, the supporting frame 10 is returned to its original position. Since the tooth load between the intermediate gears 7 and 8 is in the direction of rotating the support frame 10 counterclockwise, the driving force is sufficiently transmitted.

A means for meshing the intermediate gears 7 and 8 using the support frame 10 is also required between the gears 18 and 19 coaxial with the register roller, but since these are small gears that transmit small power, the tips of the teeth should be sharpened. All you have to do is leave it there. The rotational force to drive the fuser is large;
Particularly in the case of a pressure fixing device, the rotational force when paper passes reaches 60 to 80% of the required rotational force of the entire device. As shown in Fig. 2, the fixing device and the upper unit 1a are coaxial with the gear 12.
If the fuser is separated from the motor 2, the fuser drive connection portion will have a complicated structure, which may cause twisting and vibration of the main body side plate due to heavy loads, especially in the case of a pressure fuser.

In the conventional example, since the lower unit 1b includes the fixing device, the power transmission device is complicated and has a large number of parts.

If a jam occurs in the paper feed section, the paper feed roller remains in the lower unit, which may cause the paper to get caught in the paper feed roller and tear the paper during jam handling, making it difficult to remove the jam.

The drive motor is located at the right end of the upper unit 1a, and the fuser, which requires the most rotational force, is located at the left end of the lower unit 1b, so it is necessary to increase the rigidity of the frame of the electrophotographic apparatus, and the power of the gears is increased. The transmission efficiency also deteriorates and there is a lot of power loss.

There is a paper feed roller in the lower unit 1b which operates intermittently and whose load fluctuates, and may twist and vibrate between it and the power source side of the upper unit 1a.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic apparatus that can easily handle jamming, increase the rigidity of the main body drive system, and perform stable operation with a small number of parts.

[Means to solve the problem]

To achieve the above object, the present invention provides an electrophotographic apparatus for forming an image on a recording medium, which includes a first unit and a second unit that can be opened relatively to the first unit, A transfer means for transferring the image on the image carrier and the recording medium is provided, and the second unit includes the image carrier, a developing means, and a first rotation for fixing the image on the recording medium. a fixing means having a body and a second rotating body, a driving source, and a driving force transmitting means for transmitting the driving force of the driving source to the image carrier, the developing means, and the fixing means; This is an electrophotographic apparatus characterized by being provided with.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The embodiment described below is an electrophotographic apparatus that can be divided into upper and lower halves with a hinge as the center of rotation or a link or the like, in which the upper unit is provided with a fixing device.

3 and 4 are vertical cross-sectional views of the central part in the width direction showing an embodiment of the present invention, and FIG. 4 shows a state in which FIG. 3 is divided into upper and lower halves. The electrophotographic apparatus is provided with an opening/closing hinge 17 below the fixing device 25 at the left end of the electrophotographic apparatus 1, and the upper unit 1a and lower unit 1b are rotatable around the opening/closing hinge 17 with the BB line as a boundary. . A photosensitive drum 26 is provided approximately in the center of the upper unit 1a, and the drive motor 2
is provided at the left end of the upper unit 1a, and is located between the fixing device 25 and the photosensitive drum 26.
A paper ejection roller 24 is installed immediately to the left of the fixing device 25.
is provided. A cleaner 28 and a developing device 27 are provided in the upper unit 1a on the left and right sides of the photosensitive drum 26 in close proximity to the photosensitive drum 26.

An exposure lamp 29 equipped with a reflector is provided close to the document glass 30, and its light beam is reflected by the original that is in contact with the document glass 30, and is transmitted to the photosensitive drum via the short focus lens array 31 provided directly below. 2
The image is now focused on 6. Photosensitive drum 26
The cleaner 28 and the short focus lens array 3 are located close to the
A primary charger 32 is provided between the lower unit 1b and a transfer charger 33 is provided below the photosensitive drum 26.
It is set in. The paper feed cassette 34 is provided below the lower unit 1b so that it can be inserted from the left end. A paper feed roller 35 is provided in contact with the upper right end of the paper feed cassette 34, and a paper feed guide 36 is provided in the upper unit 1a immediately above, then makes a U-turn to the left and reaches near register rollers 37 and 38. It is being The upper registration roller 37 is provided in the upper unit 1a, and the lower registration roller 38 is provided in the lower unit 1b. The conveyor belt 39 is provided on the lower unit 1b and is driven by a conveyor belt drive gear 40 provided on the upper unit 1a.

The image forming operation is well known and will be omitted, and the gear system will be explained with reference to FIGS. 5 and 6. FIG. 5 is a side view showing a gear system according to an embodiment of the present invention, and the gear system is disposed on a side surface of an electrophotographic apparatus.
FIG. 6 shows a state in which FIG. 5 is divided into upper and lower parts. The arrow indicates the direction of rotation of the gear.

A gear 41 shown at the shaft end of the drive motor 2 is provided in the upper unit 1a, and the rotation of the gear 41 passes through intermediate gears 42 and 43 provided in the unit 1a, and is transferred to the fuser 25, which requires a large rotational force. The signal is transmitted to a gear 44 fixed to the fixing roller, and then via an intermediate gear 45 to a gear 46 fixed to the lower sheet discharge roller 24. Also, intermediate gear 47
The rotational force is transmitted from the gear 41 of the drive motor to the gear 48 fixed to the photosensitive drum 26 through. The rotational force is transmitted from the gear 48 of the photosensitive drum through the intermediate gear 49 to the gear 50 coaxially fixed to the upper register roller 37, and then through the intermediate gears 51 and 52 to the gear 53 coaxial with the paper feed roller 35. is reported.

On the other hand, from the intermediate gear 47 to the conveyor belt drive gear 40
The rotational force is transmitted to the gear 40a, which is fixed coaxially with one of the pulleys provided on the lower unit 1b and around which the conveyor belt is wound.
Rotational force is transmitted from zero. The conveyor belt driving gear 40 transmits a small rotational force, and the tooth tips of the gear are sharpened to mesh with the small gear 40 having the sharp tips.

Gear 4 that drives the fixing device 25 that requires large rotational force
4 is arranged very close to the gear 41 of the drive motor, as described above, so that the power transmission rate is good.

Furthermore, by providing the main driving parts such as the fixing device 25 and the intermittently driven paper feed roller 35, which require the most driving force, in the upper unit a on the drive motor 2 side, twisting and vibration can be prevented.

Note that the drive motor 2 is close to the opening/closing hinge 17,
The fuser 25, which tends to be heavier in pressure fusing than in heat fusing, is very close to the opening/closing hinge 17, and the upper unit 1 is mounted around the opening/closing hinge 17.
The feeling of weight when lifting a is reduced.

Note that the division according to the present invention is not limited to a hinge, but also includes a division using a link or the like.

As explained above, in an electrophotographic device that can be divided into upper and lower parts, by having the fixing device in the upper unit, there is no heavy-load power transmission part between the two upper and lower units, simplifying the configuration. Since heavy loads are not applied, the machine frame no longer twists or vibrates, and the fuser is firmly fixed.

Furthermore, since the drive motor is provided near the fixing device, power transmission efficiency is good. The paper feed roller has been moved to the upper unit, which reduces twisting and vibration of the machine frame, making it easier to clear paper jams.

〔Effect of the invention〕

As detailed above, according to the present invention, there is no heavy load power transmission part between the units, simplifying the configuration, and since no heavy load is applied between the units, twisting and vibration in the machine frame can be prevented. As a result, we were able to provide an electrophotographic device that achieves improved image quality.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional electrophotographic device;
The figure is a vertical cross-sectional view showing the state in which the figure 1 is divided into two parts, FIG. 3 is a vertical cross-sectional view of the embodiment of the present invention, and FIG.
FIG. 5 is a side view showing a gear system according to an embodiment of the present invention, and FIG. 6 is a side view showing a state in which FIG. 5 is divided into two. 1a... Upper unit, 1b... Lower unit, 2... Drive motor, 7, 8... Intermediate gear, 2
5...Fuser, 35...Paper feed roller.

Claims (1)

[Scope of Claims] 1. An electrophotographic apparatus for forming an image on a recording medium, comprising: a first unit; and a first unit that can be opened symmetrically to the first unit, the first unit having: A transfer means for transferring the image on the image carrier to the recording medium is provided, and the second unit includes an image carrier, a developing means, and a first rotating body for fixing the image to the recording medium. a fixing means having a second rotating body; a driving source; and a driving force of the driving source is applied to the image carrier;
An electrophotographic apparatus comprising: a developing means and a driving force transmitting means for transmitting driving force to a fixing means. 2. The electrophotographic apparatus according to claim 1, wherein the first unit and the second unit can be rotated and opened using the side where the fixing means is provided as a rotation fulcrum.