JPS6050563A - Developing device - Google Patents

Abstract

PURPOSE:To peel off stably a residual developer, and to carry it exactly into a hopper without making it overflow to the outside of a device, by providing a developer drop preventing means on the lower part of a developing roll and a magnetic roll which are provided with a scraper. CONSTITUTION:The first scraper 15 and the second scraper 19 are placed on a developing roll 11 and a magnetic roll 16, respectively, and surrounding bodies 17, 18 being a developer drop preventing means are provided on the lower part of both the rolls 11, 16. A residual developer on a sleeve A is peeled off by the scraper 15, caught magnetically by the magnetic roll 16, also carried mechanically, creeps into the lower part, being mixed with a new developer in a hopper 12, peeled off from the roll 16 by the scraper 19, and returned to the surface of the roll 11. Therefore, the residual developer is peeled off stably, and also the developer is peeled off stably, and also the developer can be carried exactly into the hopper without making it overflow to the outside of a device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention #J relates to a magnetic brush developing device for developing an electrostatic latent image using a developer containing magnetic toner in an electrophotographic copying machine.

Prior Art Conventionally, the developers used in developing devices for developing latent images in electrophotographic copying machines include magnetic carriers, non-magnetic toners, magnetic carriers and magnetic toners, and several types of toners that do not contain carriers. There are many multi-component developers such as those consisting of: Further, one-component developers comprising only magnetic toner or only non-magnetic toner are also known. In the above-mentioned multi-component developer, each component making up the developer must be sufficiently stirred and mixed. Therefore, in a developing device that uses a multi-component developer containing a carrier, the consumed developer remaining on the developer roll, which is a developer holding member, is scraped off from the developer roll three times and stored in the developer hopper. A stirring blade or the like is provided to mix a large amount of developer. However, even if such a mechanism is provided, deterioration of the carrier cannot be avoided, resulting in a decrease in image quality. Next, in order to prevent the deterioration of image quality due to deterioration of the carrier, a developing method using a one-component developer consisting only of toner was introduced, but even in this developing method, the developer remaining after development has become stuck to the surface of the developing roll due to pressure, frictional electricity, etc., resulting in a problem that the image quality lacks stability over time.

Therefore, in order to solve this problem, we have developed a method that effectively removes the developer after use, prevents the developer from sticking to the surface of the developing roll and changing its properties due to pressure, etc., and improving its stability over time. Various attempts have been made to achieve a certain development. Seven of them include a method using a scraper as a developer stripping member.

FIG. 7 of the accompanying drawings schematically shows an example of a developing device using this scraper. As shown in FIG. 1, this conventional developing device has an opening 1A at the bottom of a developer hopper storing developer 6, and a photoreceptor drum 2, which is the latent image forming body of the electrophotographic copying machine. A developing roll 3 having a built-in magnet is provided therebetween. These three developing rolls rotate in the direction of arrow A and pass through the opening 1A to the photosensitive drum 2.
A developer is applied to the latent image formed on the image to perform development. For this developing roll 3, the developing roll 3
A layer thickness regulating member 4 for regulating the thickness of the developer layer held thereon is associated therewith. Furthermore, a scraper 5 is provided in the opening IA of the developer hopper 1 for peeling off the developed developer layer 6A held on the developer roll 3 from the developer roll 3. In such a configuration, the developer 6B peeled off from the developing roll 3 by the scraper 5
is the magnet VC in the developing roll 3 on the back side of the scraper 5.
After being mixed with new developer 6 in the hopper 1, the developer flows as shown by arrow 8 and is deposited on the developing roll 3 again.

This type of developing device fn operates as described above without any problems when the N port IA of the hopper 1 is oriented as shown in the figure. Due to the narrowing of the current 1iR device space due to VC, the second
As shown in the figure, if the opening part IA of the hopper 1 is turned sideways, the developer peeled off from the current first roll 3 by the scraper 5 will not be able to get over the scraper 5. , the residual developer 6A on the developing roll 3 that is returned in the direction of the arrow C, stays at the bottom of the hopper 1, and is subsequently conveyed into the bowl cannot enter the hopper 1, and the As shown, it overflowed from the opening 7A at the bottom of the hopper 1, contaminating the area around the developing device, and was also seen on the FP image. An example of a configuration that can completely overcome this problem is the one disclosed in Japanese Patent Application Laid-Open No. 37-9337'1.

However, even in that configuration, there would be no problem if the arrangement between the I and the deformation is as shown schematically in FIG. A problem arises when the arrangement is as shown schematically in FIG. That is, in the developing apparatus schematically shown in FIGS. 3 and 7, the same reference numerals are used to denote the same components as those in the developing apparatus shown in FIGS. 1 and 1. Since these components operate in the same way, they will not be described again. In the developing device shown in FIGS. 3 and 3, the current fM I'
- A magnetic roll 7 is provided adjacent to the roll 3 and the scraper 5. This magnetic roll 7 consists of a sleeve 7A and a magnet roll 7B, and these sleeve 7A and magnet roll 7B rotate in the directions shown by the arrows to remove the ring 1 from the developing roller 3 by the scraper 5. It magnetically attracts the developer and transports it upward into the hopper 1.

In the arrangement shown in Fig. 3, the developer flows in the direction of the arrow, so that it passes over the upper end of the scraper 5 and returns onto the developing roll 3, so there is no problem, but in the arrangement shown in Fig. 7, there is no problem. In this case, the developer flows as shown by arrow E.
As a result, the gap between the developing roll 3 and the magnetic roll 7 is clogged, making it impossible for the residual developer 6A on the developing roll 3 that is subsequently conveyed to enter the hopper 1.
Otherwise, as shown by reference number 6G, it overflows from the bottom of the hopper 1 and scatters around the current IM device, contaminating it.

Purpose of the Invention Purpose of the Invention Problems with the prior art as described above
Considering this, regardless of the orientation of the hopper, that is, the position of the image roll operator of the image scraper, it is possible to stably move the residual developer on the developing roll and convey it continuously without overflowing to the outside of the imaging device. The purpose of the present invention is to provide a magnetic visual protection device.

Effects of the Invention According to the present invention, there is provided a developer hopper which is constructed in a magnetic brush visual imaging device for close-up electrophotography and has an opening at the bottom and stores a magnetic developer containing magnetic toner; A visual agent is provided between the opening of the hopper and the latent image forming body of the electronic Shaseigi shadan, and a visual agent is applied to the 7IC latent image formed on the m image forming body from the opening to develop it. a first developer for scraping off the developer remaining on the developer holding member after development immediately before entering the opening of the developer hopper; a peeling member, a magnetic roll that magnetically captures the developer scraped off by the first developer peeling member, and a magnetic roll that peels off the developer on the magnetic roll and removes the peeled developer from the first development pre-metal. a first developer stripping member configured to return the developer over the upper end of the developer stripping member onto the developer holding member; and between the developer holding member and the magnetic roll and the third developer By including a stripping member and a developer fall prevention means disposed below the developer stripping member of the microcosm, the residual developer on the developer holding member is separated by the third developer stripping member, and this ＃Measures to prevent the developer from falling when released;
Through the cooperative action of the magnetic roll and the first developer stripping member, the developer G111 is returned onto the developer holding member without overflowing from the developer hoe U, and the developer from the stone image forming body is continuously conveyed. It is set as #R.

Embodiments Next, the present invention will be described in more detail with regard to embodiments of the present invention based on FIGS. S to 9 of the accompanying drawings.

FIG. S is a schematic diagram showing a magnetic brush developing device as an embodiment of the present invention. It is assumed that the photosensitive drum 2tf'i, which is an m-image forming member, is rotationally driven in the direction of the arrow. The magnetic brush developing device 10 according to the present invention is disposed at a portion where the photoreceptor drum 2 moves downward, and has an image roll 11 as a developer holding member. The developing roll 11 includes a non-magnetic cylindrical sleeve IIA and a cylindrical permanent magnet 11B rotatably supported inside the sleeve IIA. The sleeve IIA and the magnet 11B are arranged so as to rotate in the directions of the arrows and maintain a predetermined gap with the photosensitive drum 2. This tax body roll 1
1 is provided with a developer hopper 12 as a developer supply member, and an opening 12 of r41' is provided below it.
The object is placed so that the developing roll 11 faces A. A magnetic developer 13 is stored in the developer hopper 12 . In this case, the magnetic developer 13 is a one-component developer consisting only of magnetic toner, and is one that adheres to the latent image formed on the photoreceptor drum 2. This magnetic developer is transported out of the developer hopper 12 by the rotation of the sleeve IIA of the developing roll 11 and the magnet 11B in the directions of arrows. A layer thickness regulating member 14 for regulating the layer thickness of the developer on the developing roll 11 is provided at the outlet of the developer hopper 12 .

In this embodiment, the layer thickness regulating member 14 also serves as the entire side plate of the hopper 12, but it may be attached separately from the hopper 12. With this layer thickness regulating member 14,
The developer on the developing roll 11 is controlled to a constant thickness rcgL, thereby forming a layer of I″1431 a on the sleeve IIA.
A constant magnetic brush is formed. The developer on the sleeve IIA is brought into contact with the m hoe formed on the photoreceptor drum 2, and some of the developer i adheres thereto and is carried away.

However, most of the developer remains on the sleeve 11A. This developed developer is peeled off from the surface of the sleeve IIA by a scraper 15 serving as a developer peeling member. The first scraper 15 is made of a non-magnetic plate, and is attached so that its tip is in contact with or very close to the surface of the sleeve 11A, and mechanically separates the developer from the surface of the entire sleeve IIA.

Next, the peeled developer is moved on the back surface of the first scraper 15 within a range that can be held by the developing roll 11.
I. When it becomes impossible to hold it, it falls downward or is magnetically collected by the magnetic roll 16.

In order to prevent the fallen developer from falling further downward and to facilitate reattachment to the visual image roll 11 and the magnetic roll 16, the lower side of the hopper 12 is shaped like the developing roll 11 and the magnetic roll 16, respectively. 1st/first enclosing body 17 concentrically enclosing
and the first envelope 18, and the distance between each of the envelopes and the developing roller A 11 and the magnetic roll 16 is determined by the layer thickness of the developer on the developing roller 11 or the magnetic roller 16.
The thickness is set to be greater than or equal to the layer thickness of the upper developer and within the range of the magnetic force of the developing roll 11 or the magnetic roll 16.

The magnetic roll 16 is composed of a non-magnetic cylindrical sleeve 16A and a cylindrical permanent magnet 16B rotatably supported within the sleeve 16A.

The sleeve 16'A is placed in parallel with the developing roll 11 at the opening 12A of the hopper 12, and the sleeve 16A and magnet 16B are each driven to rotate in the direction of the arrow.

Therefore, the developer peeled off from the sleeve IIA by the first scraper 15 is magnetically collected by the magnetic roll 16 and mechanically transported to Ki9 where it is mixed with new developer in the hopper 12 as shown by the arrow. It advances in the form of a latent sinking downward, is peeled off from the magnetic roll 16 by the first scraper 19V as a first developing scraper, and is returned to the vicinity of the surface of the developing roll 11 in the hopper 12. The flow of the developer becomes a flow that cannot be countered by the magnetic force of the new developer present in the hopper 12.
Further, a seventh enclosing body 17 and a concentric enclosing body 18, which are concentric with respect to each of the developing roll 11 and the magnetic roll 16, are arranged extremely close to the surface of the sleeve 11A1 and the sleeve 16A. Therefore, M/scraper 1
The magnetic developer Nw stripped from the sleeve IIA by 5 is reliably returned into the hopper 12 without scattering outside from the opening of the hopper 12.

In the above-mentioned embodiment, the developer fall prevention means was constituted by the first enclosure 17 and the first enclosure 18 which were formed concentrically, but according to the present invention, the developer fall prevention means is not limited to this one, but various other configurations of Sen can be considered. For some examples of these, see #51 below with reference to FIGS. Cut.

Fig. 6 td, fJl image cutting fusing fall prevention means potspar 1
The shape of the bottom of 2 is made into a simple rM gauge line, and instead of that,
This schematically shows an example in which a member 2o having a crab-shaped cross section is firmly attached to the bottom inner wall of the entire hopper 12.

FIG. 7 schematically shows an example in which 214 circumferences of a member having an arcuate cross section are added in place of the member 2o in FIG. 6.

FIG. 3 shows an example in which a plate-shaped member 22 is arranged between the first scraper 15 and the magnetic roll 16 to serve as a fall prevention member.

In any of the examples shown in FIG. N6, FIG. 7, and FIG. 3, the ti slippage of the developer is the same as that described for the embodiment shown in FIG. Well, first scraper 1
The developer peeled off from the surface of the sleeve 11A by the developer roll 11 moves on the back surface of the first scraper 15 within a range that can be held by the magnet 11B in the developing roll 11, and falls downward when it can no longer be held. Or, the developer is magnetically collected by the magnet roll 16, and at this time, the developer that has fallen downward adheres to the respective fall prevention parts #20, 21, or 22, and at the same time, the magnet 11B in the developing roll 11 again causes the developer to 8i!
/ conveyed in the direction of the scraper 15.

Therefore, in these cases as well, the distance between the developing roll 11 and the fall prevention member 20, 21, or 22 is the distance that is equal to or greater than the layer thickness of the developer on the developing roll 11 and that is covered by the magnetic force of the magnet 11B in the developing roll 11. is set to . Figure 6,
Even if the examples shown in FIGS. 7 and 7 fail, the developer will not be scattered outside the imager, and the developer can be transported stably. In particular, in the examples shown in Figures 6, 7, and 2, the hopper can be of a simple shape, making the development and adjustment of the developing device easier and reducing the overall price. .

The present invention is not limited to the first embodiment described above, and in particular, the positional relationship of the developing roll, layer thickness regulating member, magnetic roll, and scraper can be freely determined.
As shown schematically in the figure, there is no problem at all if the layer thickness regulating member 14A is arranged in positions 1 to 1, and this arrangement has the advantage that the amount of developer that can be stored increases.

In addition, as a latent image forming body, vj in an electrostatic recording device is used.
It may be an electric material, and as a scraper, a magnetic material,
It may be formed of any non-magnetic material. The developer holding member may be belt-shaped instead of cylindrical, and the present invention can be applied to a magnetic brush developing device having two or more developer holding members. Further, as the magnetic developer, the present invention is applicable not only to a one-component developer made of only magnetic toner but also to a magnetic development device using a two-component developer.

Effects of the Invention According to the invention, the developer roll J is removed after each rotation of the developer roll, regardless of the position of the scraper on the roller.
: The developer remaining on the roller is reliably peeled off and returned to the vicinity of the surface of the developing roll. Also, at this time M\i
Since it hardly mixes with the L and Y developer and there is always new YL developer in the upper part of the hopper, the fluctuation of the developer over time is extremely small, and the developer does not scatter outside the developing device. Since it can be returned to the hopper continuously, the resulting images are good and stable.

F of the drawing! 41 Description Fig. 1 is a schematic diagram showing an example of a conventional magnetic brush developing device, Fig. 2 is a schematic diagram showing another example of a conventional magnetic brush developing device, and Fig. 3 is a schematic diagram showing an example of a conventional magnetic brush developing device. FIG. M is a schematic diagram showing still another example of a conventional magnetic brush developing device, and FIG. S is a schematic diagram showing a magnetic brush developing device according to an embodiment of the present invention. FIG. 6, FIG. 87, FIG.

2... Feeling')r; Body drum, 10... Magnetic brush developing device, 11... Cedar 1. +': 4=, roll, 12
..., developer hopper, 12A...opening mJ 13.
...Magnetic developer, 14...Layer thickness regulating material, 15...
・Note/Scraper, 16...Magnetic roll, 17th river/
enclosing body, 18...g) enclosing body of τ62, 19...
No. Ω scraper.

Figure 1 6 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] In a magnetic brush developing device in an electrophotographic copying machine,
A developer hopper having an opening at the bottom and storing a magnetic developer containing magnetic toner; and a developer hopper provided between the opening of the developer hopper and a latent image forming member of an electrophotographic copying machine, A developer holding member that holds the developer to apply the developer to the latent image formed on the latent image forming body for development; and a developer holding member that holds the developer remaining on the developer holding member after development. a first developer stripping member for scraping off the developer just before it enters the opening of the developer hopper; and a magnetic roll that magnetically collects the developer scraped off by the first developer stripping member. and a first developer stripping member that strips off the developer on the magnetic roll and returns the stripped developer over the upper end of the first developer stripping member onto the developer holding member. and a developer fall prevention means disposed between the developer holding member and the magnetic roll and below the first developer peeling member and the first developer peeling member. Magnetic brush developing device.