JPH08305134A - Image forming device and electrifier attached thereto - Google Patents

Abstract

PURPOSE: To save the handling time of cleaning and to attain stable electrification over a long period by forming both side edge parts including both discharge tip parts of an electrifier, to be symmetric with respect to the center line in the longitudinal direction of the electrifier. CONSTITUTION: Shield cases 9a and 9b are constituted so that when they are arranged to face each other, both top and bottom edges are spread in the same shape. The edges of a discharge member 10 arranged between the shield cases 9a and 9b can be exposed in a spreading part and tooth-shaped discharge tip parts are formed on these exposed edges. Further, elastic terminal parts 11a and 11b are formed to be symmetric with respect to the center line in the longitudinal direction of the electrifier 7, on one end part, of the discharge member 10 and projected parts 14 and 14' are formed on both ends of the shield cases 9a and 9b. when the electrifier 7 is attached to an image forming device, the projected part. 14' in the inner part of the electrifier 7 is abutted on abutting part, 12 provided on a device main body side and restrained in the abutting position.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrostatic copying machine and a printer.

[0002]

2. Description of the Related Art In the image forming apparatus as described above, a means for uniformly charging the surface of the image carrier as a premise for forming an electrostatic latent image on the image carrier, an image carrier. 2. Description of the Related Art A charger is widely used as a means for transferring a toner image formed on a body to a transfer material such as paper and a means for separating the transfer material from an image carrier after the transfer.

As such a charger, a charger using a charging member in which a large number of discharge tips are formed in a saw-tooth shape on the edge portion arranged in the vicinity of the surface to be charged has been proposed and put into practical use. An image forming apparatus using such a charger will be briefly described with reference to FIG.

FIG. 1 is a side view schematically showing the structure of the image forming apparatus, in which the surface photosensitive layer of the cylindrical image carrier 1 extending in the direction perpendicular to the plane of the drawing and rotating in the direction of arrow A is shown. It is uniformly charged by the charger 4, and the image signal E is projected on the charged surface to form an electrostatic latent image.

When the image bearing member 1 rotates and the latent image reaches a developing portion where the developing device 2 is arranged, toner is applied from the developing device 2 to the latent image to form a toner image. further,
When this toner image reaches the transfer portion where the transfer charger 6 is arranged, a transfer material (not shown) is supplied from the conveying path 5 to the transfer portion at the same timing, and the toner image on the image carrier side is supplied. Are transferred to the transfer material.

Then, the transfer material is separated from the image carrier 1 by the action of the separation charging device 7 and is conveyed to a fixing portion (not shown) through the conveying path 8. At the time of transfer, some toner that does not contribute to the transfer and remains on the image carrier 1 is removed by the cleaner 3, and the image carrier 1 is ready for the next image forming step. It is well known that the charger may be used at the image signal E applying position, the pre-transfer position, etc., in addition to the above-mentioned parts.

The present invention relates to a charger having a saw-tooth discharge tip which is used as a separate charger of the above-mentioned image forming apparatus, and is a primary charger as shown by reference numerals 4 and 6 in the drawing. Of course, the present invention can be applied to a container, a transfer charger, and the like.

By the way, inside the image forming apparatus, toner as fine particles is transferred from the developing device to the image carrier (from the latent image to the toner image), from the image carrier to the transfer material (transfer), and from the image carrier to the cleaner. Since it is difficult to keep the toner in a sealed state at each part during this time, it is unavoidable that toner leaking from each part exists as floating toner in the device. It is the actual situation to say.

On the other hand, in order to stably and uniformly charge the surface to be charged, the chargers provided at the above-mentioned respective portions are provided with a discharge member having a saw-toothed tip at a predetermined relational position with respect to the surface to be charged. It is necessary to keep it clean and always clean. For this reason, the discharge tip of the charger needs to be cleaned in a timely manner, but since the discharge tip has low strength, it may be damaged or curved during cleaning, causing problems with the formation of the desired charged surface, and increasing the service life. There is a problem of shortening.

The present invention has been made to cope with such a situation, and in a charger having a saw-tooth discharge end, a charger having a high durability and an image forming apparatus having high durability can be saved. It is intended to be provided.

[0011]

Configuration of the Invention

In order to achieve the above object, the present invention provides a discharge member having discharge tips on both side edges in the longitudinal direction, and a discharge member sandwiching the discharge member and at this time. In a charger having a pair of insulative shield cases formed so as to expose, both side edge portions including both the discharge tip portions of the charger are symmetrical with respect to a longitudinal centerline of the charger. Charger (1) formed in a shape, or in the above (1), a charger (2) obtained by coating the discharge tip on the side far from the image carrier with an insulating material, or An image forming apparatus comprising a carrier and a charger arranged in proximity to the carrier, wherein at least one of the chargers is the charger described in (1) or (2).

With this configuration, it is possible to perform stable charging for a long period of time by eliminating the trouble of cleaning the charger, and improve the function of the image forming apparatus and reduce the cost.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS "FIG. 1" is a perspective view of a separation charger according to an embodiment of the present invention, and FIG. In the figure, reference numerals 9a and 9b denote shield cases made of an insulating resin, and a discharge member 10 made of a conductive material having an appropriate elasticity such as metal is sandwiched between the shield cases.

When the shield cases 9a and 9b are arranged so as to face each other, the upper and lower edges in the figure spread out in the same shape, and the edge of the discharge member 10 placed between them is the same. It is exposed to the expanded part. Further, a serrated discharge tip is formed on these exposed edges.

Elastic terminal portions 11a and 11b are formed at one end of the discharge member 10 symmetrically with respect to the longitudinal center line of the charger, and project at both ends of the shield case. The parts 14, 14 'are formed.

FIG. 1 shows a state in which the charger is attached to the image forming apparatus. At this time, the protrusion 14 on the back side of the charger (the side opposite to the side where the operator operates the apparatus). 'But,
The abutting portion 12 provided on the apparatus main body side is abutted and locked at this position.

At this time, the elastic terminal portion 11b is brought into contact with the terminal portion 13 connected to the power source on the main body side so as to contact the discharge member 1.
The separation bias can be applied to 0.

In order to remove the charger from the main body of the apparatus, the operator grips the projection 14 on the front side and slightly moves the entire charger in the direction of the white arrow A, so that the terminal portion 11b and the main body side terminal 13 are connected to each other. Separate. At this time, the protrusion 14 ′ is still engaged with the abutting portion 12.

Then, if the projecting portion 14 is grasped and pulled out toward the front, the charger is guided by a guide portion (not shown) provided on the main body side and can be pulled out to the outside.

As shown in FIG. 1, when incorporated in an image forming apparatus below the charger, a portion located on the opposite side of the image carrier should be surrounded by a discharge tip on the unused side. A shield member 15 made of insulating resin or the like is provided. As a result, it is possible to prevent the electric potential from being lowered on the side of the image carrier due to the discharge to the side opposite to the image carrier, and the contamination due to the adsorption of floating toner, dust and the like.

Reference numeral 16 denotes a spring which, when mounted on the main body of the apparatus shown in FIG. 1, presses the charger toward the image carrier to position it, and is limited to the coil spring as shown. Of course, it is not a thing.

Although not shown in the drawing, an insulating tape is preliminarily attached to the discharge tip of the discharge member 10. A free standing cover is capped and used by being attached to the image forming apparatus. The workability and the maintainability of the function can be improved by removing the tape or the like on the side used at that time. The case where the present invention is applied to the separation charging device has been described above, but the present invention is not limited to this, and charging used in other parts in the image forming apparatus such as a primary charging device and a transfer charging device. It is arguable that it can also be applied to vessels.

[0023]

As described above, according to the present invention,
In a charger having a discharge tip portion used in an image forming apparatus, it is possible to provide a low-cost and high-performance image forming apparatus because it is possible to maintain the performance by cleaning the discharge tip portion and to prolong the life thereof. .

[Brief description of drawings]

FIG. 1 is a perspective view of a charger showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of essential parts of the same as above.

FIG. 3 is a side view schematically showing the configuration and operation of a known image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2 Developing device 3 Cleaner 4 Primary charger 6 Transfer charger 7 Separation charger 9a, 9b Shield case 10 Discharge member 11a, 11b Elastic terminal part 12 Abutting part 13 Power supply side terminal 14, 14 'Projecting part 15 Shield member

Claims (3)

[Claims] 1. A charging device comprising a discharge member having discharge tips on both side edges in a longitudinal direction, and a pair of insulating shield cases which are formed so as to sandwich the discharge member and expose the discharge tips at this time. In the charging device, both side edge portions of the charging device including both the discharge tip portions are formed symmetrically with respect to a longitudinal centerline of the charging device. 2. The charging device according to claim 1, wherein the discharge tip on the side far from the image carrier is covered with an insulating material. 3. An image forming apparatus comprising an image carrier and a charger arranged in proximity to the image carrier, wherein at least one of the chargers is the charger according to claim 1 or 2. Image forming device.