JPS61162069A - Developing device - Google Patents

Abstract

PURPOSE:To prevent magnetic toner from stagnating and to reduce a developing device at its size by arranging an agitator on the lower part of a hopper. CONSTITUTION:A bottom plate 4a is extended from a position close to the lower part of a developing sleeve 2 in the horizontal direction by a prescribed distance and then a side wall 4b is planted on the bottom plate 4a in the vertical direction to form the hopper 4 for storing a developer. Magnetic toner is injected from the upper part into the hopper 4 and temporally stored. The agitator 5 is pivoted to a corner part formed by the bottom plate 4a and the side wall 4b in the hopper 4 to deliver the toner which may be easily stored in the bottom of the hopper 4 forcedly to the sleeve 2 while agitating the toner. Consequently, the area close to the periphery of the sleeve 2 is effectively used and the size of the developing device can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry developing device, and more particularly to a developing device that contributes to miniaturization of electrophotographic copying machines and the like.

Conventionally, as shown in FIG. 4, there is a developing device which stores the developer in a hopper 11 having a slope, and then drops the developer in an appropriate amount by its own weight to a developing sleeve 12 serving as a developer conveyor. However, in this case, since gravity is used, the placement of the hopper 11 is limited to an area above the developing sleeve 12. Of course.

Since the hopper occupies a relatively large installation space, restrictions on its placement are extremely inconvenient in terms of design, and
When downsizing the developing device, only a narrow area of the circumferential surface of the downsized developing sleeve 12 is provided as a developer supply section, which may impede the developer supply effect of the natural fall method.

Therefore, as a countermeasure, as shown in FIG.

A method of mechanically forcibly supplying the developer from the horizontal direction using an agitator 13 or the like may be considered. In this case, if the force of the developing sleeve to support the magnetic developer, such as the magnetic force of a magnet disposed within the developing sleeve 12, is weak, the developer will be packed into the space P between the lower part of the developing sleeve 12 and the hopper bottom surface 11a. state.

When the powder pressure of the packed developer increases excessively, it overflows upward at once as the developing sleeve 12 rotates. This developer overflow phenomenon adversely affects the regulation of the developer layer thickness by the doctor blade 14, which in turn leads to a deterioration in image quality.

Purpose The present invention has been made in view of the above points, and it is an object of the present invention to provide a developing device that can smoothly supply developer to a developer conveying member from a horizontal direction and is convenient for downsizing. shall be.

In order to achieve the above-mentioned object, the present invention provides a developer transporting body that carries developer on its surface and transports it along a predetermined path including a development area, and at least a lateral part of the developer transporting body. The present invention is characterized by comprising a hopper having a storage space for storing developer in the lateral direction, and a regulating means for regulating the supply of the developer from the storage space in the lateral direction to the developer conveying member.

A detailed description will be given below based on one embodiment of the present invention. FIG. 1 is a schematic diagram showing one embodiment of the developing device of the present invention. In FIG. 1, a photosensitive drum 1 as a latent image carrier is rotatably supported. The photosensitive drum 1 is constructed by forming a photosensitive layer 1b made of a photoconductive substance on the circumferential surface of a cylindrical conductive substrate 1a, and in this example, is driven clockwise at a predetermined speed. be rotated. In the vicinity of the circumferential surface of the photosensitive drum 1, various steps constituting the electrophotographic copying process, such as uniform charging, image exposure, development, transfer, and cleaning, are sequentially arranged along the rotation direction of the photosensitive drum 1. ing. In the developing process area, a developing sleeve 2 serving as a developer conveying member is rotatably supported in the counterclockwise direction in this example. The developing sleeve 2 has its surface closest to the circumferential surface of the photoreceptor drum 1 in the development area, and carries the developer onto the surface of the photoreceptor drum 1 through a static charge formed through a process of uniform charging and image exposure. It is supplied to the electrostatic latent image and turns the latent image into a visible image. Inside the developing sleeve 2, an appropriate number of magnets 3 are arranged approximately evenly along the inner peripheral surface of the developing sleeve.

A hopper 4 for storing developer is formed by extending a bottom plate 4a horizontally a predetermined distance from near the bottom of the developing sleeve 2, and then vertically erecting a side wall 4b. In this example, magnetic toner containing a magnetic substance is charged into the hopper 4 from above and is temporarily stored therein. An agitator 5 is rotatably supported at a corner portion of the hopper 4 formed by a bottom plate 4a and a side wall 4b. The agitator 5 in this example is rotated clockwise at a predetermined speed, and forcibly sends out the toner, which tends to stay at the bottom of the hopper 4 after being charged, toward the developing sleeve 2 while agitating the toner. That is, the developing sleeve 2
The structure is such that toner is supplied from the horizontal direction. As a result, the area near the circumferential surface of the developing sleeve 2 is effectively utilized, making it possible to downsize the developing device.

Between the developing sleeve 2 and the agitator 5, a partition wall 6 is erected from the bottom plate 4a to form a toner supply section F. Here, the tip 6a of the partition wall 6 is connected to the developing sleeve 2.
Its height H is set so that it is located at approximately the same height as the rotation center 0 of.

In this case, the distance between the partition wall tip 6a and the developing sleeve 2 is preferably 8 mm or less, especially 2 to 4a11.
is preferred. Providing the partition wall 6 in this manner prevents the inconvenience of the toner being forcibly fed into the gap P between the lower part of the developing sleeve 2 and the bottom plate 4a along the bottom plate 4a as the agitator 5 rotates. In this case, agitator 5
Due to the stirring action of the toner, the toner that has exceeded the partition wall tip 6a is supplied to the developing sleeve 2 side, but the position beyond the partition wall tip 6a is above the rotation center O of the development sleeve 2, and the distance is set appropriately. Therefore, most of the toner moves following the rotation of the developing sleeve 2. Therefore, the amount of toner that crosses the partition wall 6 and enters the gap P between the developing sleeve 2 and the bottom plate 4a is extremely small, and this area is filled with so-called partner toner, where the toner powder pressure increases excessively and the toner overflows all at once. It is possible to reliably prevent the "overflow" phenomenon. Also, since the toner is effectively prevented from being sent into the gap P in this way, the magnet 3 disposed inside the developing sleeve 2 is It is no longer necessary to set the magnetic force of the lower magnet 3a large, which is extremely convenient for reducing the size and weight of the developing device.In other words, since the required magnetic force is small, the magnet 3 can be downsized and the developing sleeve 2 can be made smaller in diameter. , diameter is 2
In the case of a large-diameter developing sleeve 2 of 5 mm or more, it is possible to prevent toner overflow by providing a large magnetic force, but by providing a partition wall 6, a small magnet with a small magnetic force is used to reduce the weight of the developing sleeve 2. You can also do it.

A doctor blade 7 that regulates the layer thickness of the magnetic toner carried on the surface of the developing sleeve 2 and conveyed is disposed near the peripheral surface of the developing sleeve 2 and on the downstream side of the toner supply section F in the toner conveying direction. . In this example, the distal end 7a of the doctor blade 7 is brought close to the surface of the developing sleeve 2 to form a regulation gap R along the width direction, and the toner is forced to pass through this gap R, so that the layer thickness is uniform. The configuration is such that a single layer of toner is formed. In this case, since toner overflow is reliably prevented and the toner supplied from the supply section F is conveyed in appropriate amounts, it is possible to stably exhibit the desired layer thickness regulation effect and form a single layer of toner suitable for development. can. The single layer of toner formed by the doctor blade 7 is conveyed to the above-mentioned development area as the development sleeve 2 rotates, and is used to develop the electrostatic latent image. The inventors of the present invention conducted experiments to confirm the effects of the present invention, and confirmed that it is optimal to set the height H of the partition wall 6 at the same height as the rotation center 0 of the developing sleeve 2. did.

Next, some other embodiments of the present invention will be described. Incidentally, the same components as those in the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. In the embodiment shown in FIG. 2, the partition wall 8 is provided so as to be inclined from the bottom plate 4a toward the developing sleeve 2 side.

The other configurations are the same as those of the above embodiment. Like this,
By providing the partition wall 8, a similar toner overflow prevention effect can be obtained, and the toner that tends to stay at the bottom of the hopper 4 can be smoothly sent out to the developing sleeve 2 side along the partition wall 8 with the rotation of the agitator 5. Therefore, the toner supply performance of the hopper 4 can be improved.

In the embodiment shown in FIG. 3, two circular portions 9a and 9a2 are formed at the bottom of the hopper 9 along the tip track of the agitator 5 and the circumferential surface of the developing sleeve 2, respectively, and a connecting portion between the two is formed. is the partition wall portion 9a, and its height H is made to match the height of the rotation center O of the developing sleeve 2. The other configurations are the same as those of the above embodiments. By forming the bottom of the hopper 9 in this manner, overflow of toner can be reliably prevented, and the toner can be smoothly supplied to the developing sleeve 2 without being retained at the bottom of the hopper.

In the above embodiments, a magnetic developer is used as the developer, but it is also possible to use not only a magnetic developer but also a non-magnetic developer. In this case, in order to improve the developer supply performance, it is desirable that the hopper be formed as in the embodiment shown in FIG. 2 or 3. Further, the tip of the layer thickness regulating member may be brought into pressure contact with the circumferential surface of the developing sleeve 2, and the developing sleeve 2 and the photosensitive drum 1 may be brought into rolling contact. Furthermore, the present invention can also be applied when an endless photoreceptor belt is used as the latent image carrier.

Effects As described above in detail, according to the present invention, it is possible to effectively utilize the limited area around the developer transport member, and it is also possible to reliably prevent the overflow phenomenon of the developer. Therefore, it is possible to greatly promote downsizing and compactness of the developing device, and it is also possible to stably form a uniform developer layer suitable for development. It should be noted that the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, FIGS. 2 and 3 are schematic diagrams showing several other embodiments of the present invention, and FIGS. 4 and 5 are schematic diagrams showing several other embodiments of the present invention. FIG. 3 is a schematic diagram showing a conventional developing device. (Explanation of symbols) 2.12: Developing sleeve 4.11: Hopper 4a: Bottom plate 6.8: Partition wall 6a,: Partition wall part F: Toner supply section Patent applicant Ricoh Co., Ltd. - No. 1 Drawing Officer 2 Figure i Pi 40

Claims (1)

[Scope of Claims] 1. A developer transport body that carries developer on its surface and transports it along a predetermined path including a development area, and a storage reservoir that stores the developer at least in the lateral direction of the developer transport body. A developing device comprising: a hopper having a space; and a regulating means regulating supply of developer from the horizontal storage space to the developer conveying member. 2. The developing device according to item 1 above, wherein the regulating means is a protrusion formed from a part of the hopper and protruding upward from the bottom surface of the hopper. 3. In item 2 above, the developer transporting body is cylindrical, and the tip of the protrusion is located at approximately the same height as the rotation center of the cylindrical developer transporting body. developing device. 4. In any one of the above paragraphs 1 to 3,
an agitator is disposed within the horizontal storage space;
A developing device characterized by stirring the developer in the horizontal storage space and supplying the developer to the developer conveying body through a tip of the protrusion.