JP2579137B2 - Color copier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color copying machine in which toners of respective colors are sequentially transferred from a photosensitive drum onto a transfer paper held on a transfer drum.

[0002]

2. Description of the Related Art Conventionally, for example, in a color copying machine, a latent image separated for each color is repeatedly formed on a photosensitive drum, and this is sequentially developed with toner of each color and transferred to a transfer sheet each time. The method is common. In order to perform such superposition transfer, a transfer drum that holds the transfer paper in contact with the photosensitive drum is used.

Here, this transfer drum is formed in a hollow frame shape in order to arrange a transfer charger and the like inside. Such a transfer charger discharges at a high voltage. Looking at the power supply system for this transfer charger, as shown in Japanese Utility Model Laid-Open Publication No. 56-123351, the transfer charger is conventionally provided outside the transfer drum. The electrical connection with the high voltage part is made by using a connector. However, in the case of such a method, a contact failure may occur due to oxidation of the connector portion or a noise may be generated.

[0004] The applicant of the present invention has conceived a power supply system for the transfer charger which eliminates the disadvantages of the connector system. The contents will be described with reference to FIGS. First, in a color copying machine, a transfer drum 1 for holding transfer paper is provided so as to be opposed to and separated from a photosensitive drum 2 for image formation. This transfer drum 1
2 and 3 mainly comprises a hollow drum frame 1a having a central portion of a cylindrical body left in a strip shape in the axial direction and notched by an image forming width W. A sheet gripper 3 for gripping the transfer paper is provided on a band-shaped remaining portion connecting the annular remaining portions. The sheet gripper 3 is pivotally supported by a drum frame 1a via a shaft 3a. One end of the shaft 3a is bent into an L-shape, and the L-shaped bent portion is controlled by a control cam (see FIG. (Not shown) so that the sheet gripper 3 is opened and closed. A dielectric film 4 is wound around the drum frame 1a so as to sufficiently cover the notch.

[0005] A fixed shaft 5 is provided which penetrates through the inside of the transfer drum 1 and acts as a transfer drum rotation support shaft for supporting the transfer drum 1. This fixed shaft 5
Has a hollow pipe shape, both ends of which are supported by rocking plates 6 and 7, and a spring 9 is interposed between the rocking plate 6 and a stop knob 8. Here, a plurality of rollers 10 that rotatably hold the inner peripheral side of the left end portion of the drum frame 1a are attached to the transfer drum 1 side of the swing plate 6. On the other hand, an outer rotor motor 11 is mounted on the other end of the fixed shaft 5 so as to be positioned outside the image forming width W of the transfer drum 1 and to rotate the transfer drum 1. The outer rotor motor 11 has a stator 11b mounted on a sleeve 11a fixed on the fixed shaft 5, and a rotor 11d rotatably mounted on the sleeve 11a via a bearing 11c. Here, the rotor 11d is inserted into the end of the drum frame 1a and the screw 1
2, it is fixed to the end of the drum frame 1a. As a result, the drum frame 1a is connected to the outer rotor motor 11
Of the rotor 11d. And
A lead wire 11e for the stator 11b passes through a hole formed on the circumference of the sleeve 11a and the inside of the hollow fixed shaft 5, and is drawn out to an external power source or the like.

A transfer charger 13 for transferring an image on the photosensitive drum 2 to a transfer paper is provided at a position in the transfer drum 1 opposite to the photosensitive drum 2.
The transfer charger 13 is fixed to the fixed shaft 5 via a support 14.
And has a length corresponding to the image forming width W. The high voltage line 15 for the transfer charger 13 is also drawn outside through the fixed shaft 5 and connected to a high voltage power supply.

Although the swing plates 6 and 7 are swingable about a fixed shaft 16 and the lower ends thereof are connected to a slide fitting 17 and the like, the description of the mechanism, operation, and the like will be omitted.

The shaft 2a of the photoreceptor drum 2 is supported by a non-illustrated stationary member. The photosensitive drum 2 is also driven to rotate by a motor separate from the outer rotor motor 11.

According to such a configuration, the transfer drum 1 rotates around the fixed shaft 5 by driving the outer rotor motor 11 to rotate the rotor 11d. Here, the driving means of the transfer drum 1 may be a gear as disclosed in Japanese Utility Model Laid-Open Publication No.
Since the outer rotor motor 11 is directly mounted coaxially without interposing a transmission mechanism such as a shaft coupling as in Japanese Patent Application Publication No. 218673, the rotation is stable in a smooth state without rotation fluctuation and vibration during rotation. I do. As a result, the state of the transfer paper with respect to the photosensitive drum 2 is also stabilized, and a high-quality color copy free of jitter or the like can be obtained.

[0010]

However, in the case of such a system, there is no particular concern about poor contact in that the power supply to the transfer charger 13 is directly connected to the outside by the high voltage line 15, but there is no particular concern. The voltage line 15 is connected to the output side of the high voltage generation power supply, and generates noise due to the high voltage. Since such a high-voltage line 15 is provided in the outer rotor motor 11 or the like, there is a possibility that the outer rotor motor 11 or electric components in the vicinity thereof may malfunction due to noise. If such a malfunction occurs, the reliability of the color copying machine or the like becomes low, and the color copying machine easily breaks down.

Further, in the case of a color copying machine, if the outer diameter of the transfer drum is large, the size of the entire apparatus is increased, so that an appropriate size can be maintained without increasing the outer diameter of the transfer drum. Must be something.

[0012]

A photosensitive drum, a hollow transfer drum opposed to the photosensitive drum and holding a transfer sheet, a hollow fixed shaft rotatably supporting the transfer drum, A transfer charger fixed inside the transfer drum and facing the photosensitive drum, and a color copying machine for sequentially transferring toner of each color from the photosensitive drum onto the transfer paper held by the transfer drum in an overlapping manner At
A high voltage generating power supply for supplying a high voltage to the transfer charger is provided in the transfer drum, and the transfer charger and the high voltage generating power supply are separately mounted on the fixed shaft,
The transfer charger and the high voltage generation power supply are connected by a high voltage line, and the low voltage line on the input side of the high voltage generation power supply is
It was pulled out through the inside of the fixed shaft .

[0013]

[Function] Since the high voltage generating power supply of the transfer charger is provided in the transfer drum, the influence of noise generated from the high voltage power supply system for the transfer is not exerted on the drive source of the transfer drum and other electric components, and the malfunction is prevented. It is possible to prevent the operation of the transfer drum and to perform a highly reliable operation.The transfer charger and the high-voltage generating power supply arranged in the transfer drum are connected to each other by a high-voltage line, so that they are separately provided. A transfer charger and a high-voltage generating power supply can be disposed on a fixed shaft in the transfer drum in the axial direction thereof, so that the space in the transfer drum can be effectively used. Since the outer diameter can be set to an appropriate size and connection to the outside by low voltage wire, connector
There is no danger of ignition, etc., even if such a method is used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. 2 and 3 will be described using the same reference numerals. In this embodiment, a high voltage generating power supply 18 for the transfer charger 13 is provided in the transfer drum 1. The high voltage generation power supply 18 is attached to the fixed shaft 5 via a support 19 in the image forming area W. The high-voltage line 20 on the output side of the high-voltage generation power supply 18
Are connected to the transfer charger 13. The low-voltage line 21 on the input side of the high-voltage generating power supply 18 is connected to the fixed shaft 5.
Is drawn out through the fixed shaft 5 through a hole formed at the outside. Therefore, the low voltage line 21 passes through the outer rotor motor 11.

According to such a configuration, the high-voltage portion which causes noise, that is, the high-voltage generating power supply 18, the high-voltage line 20, and the transfer charger 13 are all processed in the transfer drum 1, and the external electrical connection is made. The electrical connection is limited to the low-voltage part by the low-voltage line 21, and the outer rotor motor 11 and other electrical components do not malfunction due to noise or the like due to the high-voltage line 20. In the case where the high-voltage wire is directly drawn out to the outside, there is a risk that ignition or noise may occur due to poor contact of the high-voltage connecting portion when the transfer drum 1 or the transfer charger 13 is attached or detached. For example, the connection to the outside by the low-voltage wire 21 does not involve a danger such as ignition even if a connector or the like is used.

In particular, the high-voltage generating power source 1 and the transfer charger 13 are separate components and are mounted separately on the fixed shaft 5, so that the high-voltage generating power source 1
Is attached, the outer diameter of the transfer drum 1 is not increased, whereby the transfer drum 1 having an appropriate outer diameter can be obtained.

The outer rotor motor 11 may be attached to the transfer drum 1 without having the same diameter even outside the image forming area. For example, the transfer drum 1 may have a smaller diameter outside the image forming area. 1, the outer rotor motor 11 may be attached with a smaller diameter, or conversely, the outer rotor motor 11 may be attached with a larger diameter. The point is that it is only necessary to be coaxial with the transfer drum 1.

[0018]

As described above, according to the present invention, since the high voltage generating power supply for the transfer charger is provided in the transfer drum, the influence of noise generated from the high voltage power supply system for transfer can be reduced. It has no effect on the parts and can prevent malfunctions, can perform highly reliable operation, and can be connected to the transfer charger arranged in the transfer drum with a high voltage generation power supply and a high voltage line. Since they are provided separately, the transfer charger and the high-voltage generating power supply can be disposed on the fixed shaft in the transfer drum in the axial direction thereof, thereby effectively utilizing the space in the transfer drum. As a result, the outer diameter of the transfer drum can be set to an appropriate size, and the transfer drum can be connected to the outside by a low-voltage line.
Danger of ignition etc. even if connectors are used because of the connection
And the like.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the contents of an application already filed by the present applicant.

FIG. 3 is a vertical sectional front view thereof.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transfer drum 2 photoreceptor drum 5 fixed shaft 13 transfer charger 18 high voltage generation power supply 20 high voltage line 21 low voltage line

Claims (1)

(57) [Claims] A photosensitive drum, a hollow transfer drum opposed to the photosensitive drum and holding transfer paper, a hollow fixed shaft rotatably supporting the transfer drum,
A transfer charger fixed inside the transfer drum and facing the photosensitive drum, and a color copying machine for sequentially transferring toner of each color from the photosensitive drum onto the transfer paper held by the transfer drum in an overlapping manner A high voltage generating power supply for supplying a high voltage to the transfer charger is provided in the transfer drum, and the transfer charger and the high voltage generating power supply are separately mounted on the fixed shaft, and the transfer charger and the Connect to a high-voltage generation power supply with a high-voltage line, and
Connect the low-voltage line on the input side of the high-voltage generation power supply inside the fixed axis.
Color copier, which is drawn out to the outside .