JPH11311895A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent developer from being excessively supplied and to secure the flowability of the developer by providing a sheet member with a long hole having an inclined edge in the rotating direction of the sheet member. SOLUTION: The plural long holes 421 having the inclined edges in the rotating direction A of the rectangular film being the sheet member are formed at the rectangular film. Thus, since the surface area of the rectangular film becomes small, the non-magnetic one-component developer is prevented from being excessively supplied to a supply roller. Besides, the parallelogram long holes are also included in the holes 421 and the holes 421 are symmetrically arranged by making the downstream parts 422 thereof in the rotating direction face the center 423 of the rectangular film in the longitudinal direction. To put it more concretely, the plural parallelogram long holes 421 are arranged at the pitch of 5 to 7 mm at a shaft-side part obtained by leaving 2 to 5 mm from the leading edge of the rectangular film, for example. Besides, the area of the parallelogram hole is about 30 to 60 mm<2> and the inclined angle thereof is about 50 to 65 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus using a non-magnetic one-component developer, such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile, the electrostatic latent image is visualized by attaching a developer to the electrostatic latent image formed on the surface of a photosensitive drum, for example. The image formed on the paper is transferred by attaching the image formed by the developer to the paper.
Some of such image forming apparatuses use a so-called non-magnetic one-component developing method in which only a toner, which is a colored non-magnetic charged powder, is used as a developer. Here, FIG.
FIG. 3 is a diagram illustrating an example of a developing unit of an image forming apparatus using a non-magnetic one-component developing method. FIG. 3 shows the photosensitive drum 1, the developing roller 2, the supply roller 3, the stirring paddle 4, and the developer container 5. In the image forming apparatus using the non-magnetic one-component developing method, the stirring paddle 4 is
It has a plate-shaped shaft member 41 that rotates in the direction of arrow A and a rectangular film 42 such as a PET film attached to the shaft member 41. When the shaft member 41 is driven by driving means (not shown) to rotate the shaft member 41 in the direction of arrow A, the rectangular film 42 also moves in the rotation direction A and is stored in the developer container 5. The non-magnetic one-component developer 6 is stirred. A part of the non-magnetic one-component developer 6 placed on the rectangular film 42 and stirred is sent to the supply roller 3.
The non-magnetic one-component developer 6 sent to the supply roller 3 is
When the supply roller 3 rotates in the direction of arrow A3, the supply roller 3 is sent to a contact portion 23 where the supply roller 3 and the development roller 2 come into contact with each other, and adheres to the surface of the development roller 2 by the sliding contact between the supply roller 3 and the development roller 2. The non-magnetic one-component developer 6 attached to the surface of the developing roller 2 is conveyed to the developing unit 12 where the photosensitive drum 1 and the developing roller 2 come into contact with each other by the rotation of the developing roller 2 in the direction of arrow A2. During this conveyance, a charge is given to the non-magnetic one-component developer 6.
The non-magnetic one-component developer 6 is charged by the developing roller 2
This is performed by a thin layer forming blade 7 which comes into contact with the surface at a predetermined pressure. The thin layer forming blade 7 abuts against the surface of the developing roller 2 at a predetermined pressure, thereby forming a uniform thin layer of the non-magnetic one-component developer 6 having a predetermined thickness.
Form on the surface. At this time, the non-magnetic one-component developer 6
Triboelectrically charged. The non-magnetic one-component developer 6 charged by the thin layer forming blade 7 and conveyed to the developing unit 12 is transferred to the photosensitive drum 1 in the developing unit 12.
It is attached to the electrostatic latent image on the surface and development is performed. The developed image on the surface of the photosensitive drum 1 is
Is transferred to the transfer unit 18 in contact with the transfer roller 8 by rotation in the direction of arrow A1, and is transferred to a sheet moving in the direction of arrow P.

[0003]

By the way, a non-magnetic one-component developer is sent to the supply roller by the stirring paddle, but the supply amount varies greatly depending on the shape of the film. If the supply amount of the non-magnetic one-component developer from the stirring paddle becomes excessive, the stress at the time of sliding contact between the supply roller and the developing roller also becomes excessive, and eventually there is a problem that fog is generated. Occurs. In order to solve the problems in the prior art, the present invention is to improve an image forming apparatus and provide a long hole having an edge inclined with respect to the rotation direction of a sheet member such as a film in the sheet member. Accordingly, an object of the present invention is to provide an image forming apparatus capable of preventing excess supply and securing the fluidity of the developer. Further, since the developer is required for most document sizes in the central portion in the longitudinal direction of the sheet member, the supply amount tends to be insufficient. Therefore, another object of the present invention is to supply more developer to the central portion in the longitudinal direction of the sheet member.

[0004]

In order to achieve the above object, the invention according to claim 1 comprises a developer container for containing a non-magnetic one-component developer, and a non-magnetic developer contained in the developer container. An image forming apparatus comprising: a developer stirring means for stirring a magnetic one-component developer by rotating a sheet member;
An image forming apparatus is characterized in that a long hole having an edge inclined with respect to the rotation direction of the sheet member is provided in the sheet member. According to the image forming apparatus of the first aspect, since the sheet member has the long holes, it is possible to prevent the developer from being excessively supplied to the supply roller or the like. Further, since the edge of the long hole is inclined with respect to the rotation direction of the sheet member, the developer loaded on the portion where the hole is not provided also easily falls through the long hole, and the developer Fluidity can be ensured. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the plurality of slots provided in the sheet member include a parallelogram-shaped slot, and each of the slots is located downstream of the rotation direction. The gist is that the portion is arranged facing the longitudinal direction of the sheet member. According to the image forming apparatus of the second aspect, since the plurality of long holes including the parallelogram-shaped ones are each arranged with the downstream portion in the rotation direction facing the center in the longitudinal direction of the sheet member. This makes it easier for the developer to collect around the center of the sheet member in the longitudinal direction, and to supply a large amount of developer near the center of the sheet member in the longitudinal direction, thereby preventing the supply amount from becoming insufficient.

[0005]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
This embodiment is a specific example of the present invention.
It is not intended to limit the technical scope of the present invention. Here, FIG. 1 is a diagram showing a configuration around a developing unit of the image forming apparatus according to one embodiment of the present invention. FIG. 1 shows a photosensitive drum 1, a developing roller 2, a supply roller 3, a stirring paddle 4, and a developer container 5. The image forming apparatus according to the present invention is realized by, for example, a copier, a printer, a facsimile, or the like, and includes a developer container 5 for storing a non-magnetic one-component developer 6 and the developer container 5.
A stirring paddle 4 (developer stirring means) for rotating the rectangular film (sheet member) to stir the non-magnetic one-component developer 6 accommodated in the non-magnetic one-component developer 6 is the same as the conventional one. The image forming apparatus is particularly different from the conventional one in that a long hole having an edge inclined with respect to the rotation direction of the rectangular film 42 'is provided in the rectangular film 42'. In the image forming apparatus, the stirring paddle 4 includes a plate-shaped shaft member 41 that rotates in the direction of arrow A,
And a rectangular film 42 'such as a PET film attached thereto. When the shaft member 41 is driven by driving means (not shown) to rotate the shaft member 41 in the direction of arrow A, the rectangular film 42 ′ also moves in the rotation direction A and is stored in the developer container 5. The non-magnetic one-component developer 6 is stirred. A part of the non-magnetic one-component developer 6 placed on the rectangular film 42 ′ and stirred is sent to the supply roller 3. Here, FIG. 2 shows an example of the shape of the rectangular film. As shown in FIG. 2, the rectangular film 42 'is provided with a plurality of long holes 421 each having an edge inclined with respect to the rotation direction A of the rectangular film 42'. As a result, the surface area of the rectangular film 42 'is reduced, and the non-magnetic one-component developer 6 is prevented from being excessively supplied to the supply roller 3. The elongated holes 421 also include those having a parallelogram shape. Each elongated hole 421 has its downstream portion 422 in the rotational direction symmetrically arranged toward the longitudinal center 423 of the rectangular film 42 ′. Have been. More specifically, for example, a plurality of parallelogram-shaped long holes 42 are arranged at a pitch of 5 to 7 mm in an axial side portion leaving 2 to 5 mm from the tip of the rectangular film 42 '. The area of this parallelogram is 30-60mm
It is about ² and the angle of the parallelogram is about 50 to 65 °. The hole 424 at the longitudinal end and the center of the rectangular film 42 'is triangular. The formation of the edge of the long hole 421 by tilting in the rotation direction A of the rectangular film 42 'instead of simply providing the hole as described above is performed by the non-magnetic one-component developing device stirred by the rectangular film 42'. This is because the binding between the powders of the developer 6 is broken and the fluidity of the non-magnetic one-component developer 6 is ensured. For example, when a rectangular hole is provided along the rotation direction A of the rectangular film 42 ', the non-magnetic one-component developer 6 in which a portion without a hole is on a locus drawn by rotation is agitated by a film having no hole. In the same manner, the film is pressed against the supply roller 3 by the rotation of the film. At this time, the non-magnetic one-component developer 6 receives stress, and thus cannot maintain fluidity. On the other hand, if the long hole 421 is inclined with respect to the rotation direction A of the rectangular film 42 ′ as described above, the non-magnetic one-component developer 6
Is also moving in the lateral direction when moving along the rotation direction A. Therefore, only a part of the developer passes through the hole 421, and the part of the developer is not always pressed by the film. The developer is uniformly stirred to ensure fluidity.
Furthermore, since the downstream portion 422 in the rotation direction of each long hole 421 is arranged toward the longitudinal center 423 of the rectangular film 42 ′, the non-magnetic one-component developer 6 moves to the longitudinal center 423 while moving. As a result, a large amount of the developer 6 can be supplied to the vicinity of the longitudinal center 423 where the developer 6 is likely to run short. The thickness of the rectangular film 42 'is, for example, 0.1 mm to 0.1 mm.
About 5 mm is preferable. This is because when the thickness is thin, the film loses the weight of the developer 6 and cannot be stirred, and when too thick, an unpleasant sound is generated when the rectangular film 42 ′ rubs against the developer container 5. This is because In mass production, a member dimension tolerance and an assembly tolerance are required, and a gap is generated in the axial direction between the developer container 5 and the rectangular film 42 '. If the gap is large, the developer 6 in the gap is not agitated and is not developed, so that the state is different from that of the other part. May occur. Such a state can be prevented, for example, by setting the gap to 2 mm or less. As described above, in the image forming apparatus according to the present embodiment, since the rectangular film has the long holes, it is possible to prevent the developer from being excessively supplied to the supply roller and the like. Further, since the edge of the long hole is inclined with respect to the rotation direction of the rectangular film, the developer loaded on the portion where the hole is not provided easily falls through the long hole, and the developer Liquidity can be secured. Further, since a plurality of long holes including a parallelogram are arranged with their downstream portions in the rotational direction facing the center of the rectangular film in the longitudinal direction, the developer can be disposed in the longitudinal direction of the rectangular film. A large amount of developer can be supplied to the vicinity of the center in the longitudinal direction of the rectangular film in which the developer tends to gather near the center and the developer tends to run short.

[0006]

In the above embodiment, the developer is sent to the supply roller by the stirring paddle, but the invention is not limited to this, and the developer may be sent directly to the development roller. In the above embodiment, a film such as PET is used for the sheet member, but the invention is not limited to this. Also, the shape of the slot,
The size and the like are not limited to those described in the above embodiment. This is an example of such an image forming apparatus in the present invention.

[0007]

As described above, according to the image forming apparatus of the first aspect, since the slot is provided in the sheet member, it is possible to prevent the developer from being excessively supplied to the supply roller or the like. Can be. Further, since the edge of the long hole is inclined with respect to the rotation direction of the sheet member, the developer loaded on the portion where the hole is not provided also easily falls through the long hole, and the developer Fluidity can be ensured.
According to the image forming apparatus of the second aspect, since the plurality of long holes including the parallelogram-shaped ones are each arranged with the downstream portion in the rotation direction facing the center in the longitudinal direction of the sheet member. This makes it easier for the developer to collect around the center of the sheet member in the longitudinal direction, and to supply a large amount of developer near the center of the sheet member in the longitudinal direction, thereby preventing the supply amount from becoming insufficient.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration around a developing unit of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a shape of a sheet member according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a configuration around a developing unit of a conventional image forming apparatus.

[Explanation of symbols]

 Reference numeral 4: stirring paddle (developer stirring means) 5: developer container 6: non-magnetic one-component developer 42 ': rectangular film (sheet member) 421: long hole 422: downstream portion of the long hole in the rotation direction 423: rectangular Longitudinal center of shape film

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masayuki Ishii 1-2-2, Tamazo, Chuo-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (72) Inventor Keisuke Oba 1-2-2, Tamazuki, Chuo-ku, Osaka, Osaka No. 28 Mita Industrial Co., Ltd.

Claims (2)

[Claims] A developer container accommodating a non-magnetic one-component developer; and a developer stirring means for stirring the non-magnetic one-component developer stored in the developer container by rotating a sheet member. An image forming apparatus comprising: a long hole having an edge inclined with respect to a rotation direction of the sheet member; 2. A plurality of slots provided in the sheet member, the slots having a parallelogram shape, and each of the slots is arranged with its downstream portion in the rotation direction facing the longitudinal direction of the sheet member. 2. The image forming apparatus according to 1.