JPH01239576A - Developing device - Google Patents

Abstract

PURPOSE:To perform developing of high image quality by making one edge of a plate-shaped elastic blade press-contact with a periphery orthogonal to the rotation direction of a developer carrier and bonding a plane surface on a thick side except at least a press-contact part to a fixing member provided in a housing. CONSTITUTION:The title device includes a rotating endless developer carrier 29 and the plate-shaped elastic blade 47 regulating developer 28 to specified layer thickness. One edge of the elastic blade 47 is made to press-contact with the periphery orthogonal to the rotation direction of the developer carrier 29 and the plane surface on the thick side except at least the press-contact part is bonded to the fixing member 63 provided in the housing 33. Therefore, the line pressure of the elastic blade 47 can be kept constant and thin layer formation and electrification amount on the developer carrier 29 are uniformized. Thus, developing of high image quality becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to image forming apparatuses such as copying machines and printers that apply electrophotography.

BACKGROUND OF THE INVENTION Conventionally, developing methods using a dry developer are broadly divided into two types: methods using a two-component developer and methods using a one-component developer.

The method using a two-component developer uses a mixed developer of toner and carrier, so it requires a toner concentration control device to maintain a constant mixing ratio of toner and carrier, and has disadvantages such as periodic replacement due to carrier deterioration. have. Therefore, recently, in order to eliminate the above-mentioned drawbacks, a developing method using only a one-component developer without using a carrier has been proposed.

This developing method is disclosed in, for example, Japanese Unexamined Patent Publication No. 60-51856, and its construction is shown in FIGS. 8 and 9.

In FIGS. 8 and 9 (Japanese Unexamined Patent Publication No. 60-51856), 1 is a developing roller, 2 is a toner, 3 is a hopper, and 4 is an elastic blade. 5 is the front frame, and the housing 6
The support member 7 is rotatably attached to the housing 6 and rotated by an adjustment screw 8 of a support member 7 provided on the housing 6. Further, the elastic blade 4 is screwed to the front frame 5 via a blade holder 9. IO indicates a photoreceptor.

The developing roller l is made of a metal material with an uneven surface, and toner 2 is supplied from a hopper 3 to the developing roller l.

Next, when the developing roller 1 rotates in the direction of the arrow, the toner 2 is charged to a predetermined polarity by the elastic blade 4 that is in sliding contact with the surface of the developing roller 1, and is coated on the surface of the developing roller 1. Next, when the charged toner 2 faces the electrostatic latent image on the photoreceptor 5, it flies off and develops.

Problems to be Solved by the Invention However, this type of system has problems in forming a uniform thin layer of developer (toner) on the developing roller and in charging properties, making it difficult to reproduce high-quality images. Ta.

That is, in the case shown in FIGS. 8 and 9, in order to form a uniform thin layer of toner on the developing roller l, the front frame 5 is rotated by the adjustment screw 8 of the support member 7, and the elastic The pressure of the body blade 4 is set to a predetermined value. However, the elastic blade 4 is fixed to the front frame 5 via a blade holder 9 with screws. Therefore, the linear pressure of the elastic blade 4 in the axial direction of the developing roller 1 fluctuates between the threaded parts, and the layer thickness and charge amount of the toner on the developing roller 1 fluctuate.As a result, during development, Density unevenness occurred, making it difficult to reproduce high-quality images.

The present invention solves the conventional problems and provides a developing device capable of reproducing high quality images.

Means for Solving the Problems The developing device of the present invention includes a rotating endless developer carrier and a plate-shaped elastic blade that regulates the developer to a predetermined layer thickness. It is in pressure contact with the outer circumferential surface perpendicular to the rotational direction of the agent carrier, and at least the plane on the thickness side excluding the pressure contact portion is adhered to a mounting member provided on the casing.

Effect The effect of this technical means is as follows. By pressing one end of the plate-shaped elastic blade against the outer circumferential surface perpendicular to the rotational direction of the developer carrier, and gluing at least the thicker plane excluding the press-contact portion to a mounting member provided on the housing, the elastic blade The linear pressure can be kept constant, and the formation of a thin layer on the developer carrier and the amount of charge become uniform. As a result, high-quality development becomes possible.

Example Examples of the present invention will be described below.

1 to 7 show a first embodiment of the present invention, which is an example used in an electrophotographic copying machine.

In FIG. 1, reference numeral 22 denotes a charge carrier, such as electrostatic recording paper or a photosensitive drum. In this embodiment, the charge carrier 22 is a photosensitive drum having a photoconductor 24 such as zinc oxide, selenium, or an organic photoconductive material supported on the surface of an aluminum base 23 (therefore, hereinafter referred to as the charge carrier). 22 is referred to as a photosensitive drum 22). Reference numeral 25 denotes a charger which applies a negative corona to the photoconductor 24 on the photosensitive drum 22 using a first DC high-voltage power supply 26, for example, a negative corona in the case of zinc oxide and a positive corona in the case of selenium, thereby covering the entire surface of the photoconductor 24. It charges the battery with electricity.

Reference numeral 27 denotes an optical section that projects a patterned optical image onto the photosensitive drum 22 to form an electrostatic latent image. A developer 28 is a normal one-component insulating toner.

Note that the developer 28 may be a magnetic toner or a non-magnetic toner.

Reference numeral 29 denotes a developing roller which is a developer carrier, and for example, a metal roller made of stainless steel, aluminum, etc., a roller whose surface is coated with resin, etc. is used. Preferably, as shown in FIG. The outer circumferential surfaces 29a and 29b are smooth at both ends, and the center surface 29c has a rough surface with fine irregularities, and is installed at a constant distance from the photosensitive drum 22, for example, in a counterclockwise direction as shown in FIG. Rotate it. A cylindrical elastic body 30 is a first supply means for supplying the developer 28 to the developing roller 29. The cylindrical elastic body 30 is a fur brush, a roller made of a sponge, etc., and is applied to the outer peripheral surface of the mandrel 31. A layer of elastic material 32 is formed.

In this embodiment, the cylindrical elastic body 30 is a fur brush,
The elastic material 32 is made of conductive fur using rayon fiber containing carbon.

Further, the fur brush 30 is surrounded by a housing 33, is in sliding contact with the surface of the developing roller 29, and is rotated, for example, in a clockwise direction and at a circumferential speed higher than the circumferential speed of the developing roller 29. By setting the circumferential speed of the fur brush 30 in this manner, it is possible to increase the amount of developer 28 supplied to the developing roller 29, improve the followability of coating, and reduce spillage of the developer 28. Furthermore, the developer 28 adhering to the surface of the developing roller 29 can be scraped off after the developing process, and the history on the developing roller 29 can be erased. Further, the fibers of the fur brush 30 are
As shown in the figure, the developer 28 is transferred to the fur brush 30 during rotation.
0 Both ends have a spiral shape moving from the outer periphery to the center.

Reference numeral 34 denotes a developer storage means, which includes a storage section 35 that stores the developer 28 and a second supply means 3 that supplies the developer to the back of the first supply gauntlet 30.
It consists of 6 parts. Further, the storage section 35 has a developer 2 at one end.
It has eight replenishment openings 37 and is formed from a part of the housing 33. Further, the second supply means 36 fixes one end of a sheet-like elastic member 39 made of polyethylene terephthalate or the like with a thickness of about 30 to 80 μm to the outer peripheral surface of the mandrel 38, and rotates or swings the mandrel 38. The developer 28 is supplied to the first supply means 30. In this embodiment, the mandrel 38 rotates clockwise. Reference numeral 40 denotes a partition plate serving as a circulation means, which connects the first supply means 30 and the second supply means 36.
The developer 28 is provided between the first supply means 30 and the second supply means 30.
The supply means 36 has an opening 41 which flows in and out through a lock. A scraping plate 42 is formed in the housing 3301, and slides into contact with the fur brush 30 to remove the developer 2 in the fur brush 30.
This is to make the amount of the developer 8 uniform and to scrape off the overcharged developer 28 inside the fur brush 30.

43 is a lid of the replenishment opening 37. 44 is a partition plate,
The developer roller 29 is provided between the developer roller 29 and the second supply means 36 at a position where the developer 28 in the storage section 35 is not directly supplied to the developer carrier 29. Further, a gap δ is provided between the two ends of the partition plate 44 and the outer peripheral surface of the fur brush 30.

Good performance was achieved when the gap δ was 0.5 to 3 mm.

Reference numeral 62 denotes a remaining amount detection means for detecting the remaining amount of the developer 28, and is provided between the partition plate 44 and the partition plate 400. The remaining amount detection means 62 is a well-known sensor that detects the amount of developer by imaging, transmittance, or the like.

As shown in FIG. 2, 45 is a bearing for the developing roller 29;
is a bearing of the fur brush 30. Reference numeral 47 denotes a plate-shaped elastic blade that regulates the layer thickness of the developer 28. In this embodiment, a rubber blade such as urethane rubber is used, but other rubber materials or elastic blades such as polyethylene terephthalate may be used as the elastic blade material. It may be made of a certain synthetic resin, or an elastic metal such as phosphor bronze or spring steel, or it may be an elastic metal or synthetic resin coated with a fluororesin. Further, the precision of the end surface of the elastic blade 47, the mounting position and method have a great influence on the formation of a uniform thin layer of the developer 28. The straightness of the edge 47A of the elastic blade 47 is 001
The blade 27 is precisely finished with less than 5 holes, and is mounted in pressure contact with the developer carrier at a surface including at least the downstream edge 47A of the blade 27 with respect to the moving direction of the developer roller 29.

As shown in Figure 4, the installation method is as follows:
The end on the side 7A is pressed onto the developing roller 29, and at least the flat surface 47B of the shaded part of the other end is adhered to the mounting member 63 provided on the housing 33 using, for example, hot melt, which allows uniform adhesion in a short time. It is. In addition, the adhesive surface end 4 of 29 examples of the developing roller
7C is provided substantially parallel to the rotational axis X of the developing roller 29.

Reference numerals 64A and 64B are adjustment screws which are pressure adjustment mechanisms and are used to adjust the pressure of the elastic blade 47 against the developing roller 29 to a predetermined value. The pressure adjustment is done by the mounting member 63.
and an adjustment screw 64A provided between the housing 33 and the housing 33.

After adjusting the predetermined blade pressure with 64B, tighten the fixing screw 65A.
.

65B fixes the mounting member 63 to the housing 33. Further, the width of the elastic blade 47 is set to such a length that it comes into contact with the outer circumferential surfaces 29a and 29b at both ends of the developing roller 29, as shown in FIGS. 2 and 5.

48 and 49 are outer peripheral surfaces 29a and 29 at both ends of the developing roller 29.
A first sealing material surrounds b and blocks the developer 28 moving to both ends thereof, and is made of an elastic material such as woven fabric, nonwoven fabric (felt), sponge, or rubber.

51 is the developing roller 29 and the first sealing material 48.4
9 and the elastic blade 47.
The sealing material is made of an elastic material such as sponge or rubber. 52. 53 is a developer 28 that moves to both ends.
In order to further block the
It is made of an elastic material such as 150 μm polyethylene terephthalate or metal. Also, elastic sheet 52. 53 has one end connected to the first sealing material 48. 49, and attach the other end to the blade edge 47 in the direction of rotation of the developing roller 29.
It protrudes downstream from A and is provided between the developing roller 29 and the second sealing material 50.51. 54. Reference numeral 55 denotes a presser plate spring that improves the adhesion of the elastic blade 47 to the developing roller 29, and the second sealing material 50, 51 and the elastic sheet 52. It is installed by pressing 53.

56 is a means for preventing the developer 28 from spilling;
The developing roller 29 and the fur brush 3
0 and below the developing roller 29. The spill prevention means 56 includes a U-shaped leak prevention member 57 and a leak prevention sheet 58 whose one end is fixed to the leak prevention member 57 and the other end is in light contact with the surface of the developing roller 29.
It consists of Note that one end of the leak prevention sheet 58 of the spill prevention means 56 may be provided on the casing 33. In addition, the width of the leak prevention sheet 58 is equal to the width of the outer circumferential surface 2 at both ends of the developing roller 29.
9a and 29b, and both ends thereof are pressed against the developing roller 29 by sealing members 48 and 49 provided at both ends of the developing roller 29, as shown in FIG. Further, the end of the leak prevention sheet 58 on the side that comes into light contact with the surface of the developing roller 29 is located on the upstream side of the line connecting the centers of the developing roller 29 and the fur brush 30 with respect to the rotating direction of the fur brush 30. and a fur brush 30. Further, the leak prevention sheet 58 is made of an elastic material such as polyethylene terephthalate or urethane rubber, and in this embodiment, urethane rubber with good adhesion to the developing roller 29 (the thickness at this time is preferably about 50 to 200 μm) is used. ing. The leak prevention member 57 is made of metal such as stainless steel or aluminum, and even if the developer 28 leaks from the developing roller 29 and the gap in the leak prevention sheet 58, the receiver stops the developer from falling downward. In this case, since the leakage of the developer 28 is almost completely stopped by the leakage prevention sheet 58, the capacity of the leakage prevention member 57 may be small.

As shown in FIG. 1, reference numeral 60 denotes a second DC high-voltage power source which is an application means for applying a voltage, and applies a voltage between the developing roller 29 and the fur brush 30 to charge the surface of the developing roller 29. This is to adjust the layer thickness of the developer 28. Further, although the applying means 60 uses a DC bias voltage in this embodiment, a voltage obtained by superimposing an AC voltage on a DC voltage may also be used.

By using a conductive material, the fur brush 30 has the function of preventing overcharging of the frictionally charged developer 28 on the developing roller 29 and making the potential uniform. Therefore, the specific resistance of the fur brush 30 is less than about IQ+@Ω, preferably 103ΩC111 to 107Ωcm.
It is better to use conductive materials.

Furthermore, as the fur brush 30, other conductive fibers may be used instead of just conductive rayon fibers as in this embodiment, or a fur brush made by electrostatic flocking may be used to make the coating uniform. It is also effective to use

Furthermore, it goes without saying that the above-described effects of frictional charging, coating, etc. can be effectively performed even if a conductive sponge, conductive cloth, or soft wire brush is used as the elastic material 32 of the cylindrical elastic body 30. . Note that when the developer 28 is a one-component magnetic toner, a magnetic roller is used as the mandrel 31, a magnetic brush is formed on the outer periphery, and a cylindrical elastic body 3 is formed.
It is also effective to set it to 0.

The operation of the developing device of the first embodiment configured as described above will be explained.

Here, in order to make the operation easier to understand, the photosensitive drum 22
The upper photoconductor 24 is made of zinc oxide, and the cylindrical elastic body 30 is made of carbon-containing rayon fiber 36 having a specific resistance of about 10'Ω as an elastic material 32 on an aluminum core 31.
The surface roughness of the fur brush and the developing roller 29 is 5 μmRmax.

The linear pressure of the elastic blade 47 in pressure contact with the developing roller 29 was 25 g/c+++, the gap between the photosensitive drum 22 and the developing roller 29 was 0.151 IIIll, and the developer 28 was an ordinary positively charged non-magnetic one-component toner. did.

In FIG. 1, a first high-voltage DC current R26 is connected to the charger 25.
A high voltage of about -6 kV is applied, and the entire surface of the photosensitive drum 22 is negatively charged to about -600 V by a negative corona. An optical section 27 is attached to a negatively charged photosensitive drum 22.
If a reflected image (pattern light image) of a document irradiated by a halogen lamp or the like is projected using the method, the portion corresponding to the non-image area of the document on the photosensitive drum 22 will be approximately Ov due to the reflected light.
The static electricity is removed to a residual potential close to , forming a positive electrostatic latent image.

During this time, the developer 28 in the storage section 35 is transferred to the second supply means 3.
6 into the fur brush 30 through the opening 41. Since the developer 28 is not directly supplied to the developing roller 29 by the partition plate 44 during this supply, the uncharged developer 28 does not adhere to the developing roller 29.

Excess developer 28 in the fur brush 30 is removed by scraping plate 4.
2 and is supplied in an appropriate amount, and the scraping plate 42
It is positively charged due to friction with the housing 33 and the housing 33 .

Next, an electric field is generated between the developing roller 29 and the fur brush 30 by the charged developer 28 in the fur brush 30, and the surface of the developing roller 29 is coated with the charged developer 28.

At this time, a voltage of about θ to 250 V is applied from the second DC high voltage power supply 60 to adjust the layer thickness. Also, by applying this voltage, when the developer 28 is transferred from the fur brush 30 to the developing roller 29, even if there is uncharged developer 28 or developer 28 charged with the opposite sign in the developer 28, the developer 28 is uncharged. The developer 28 charged with the opposite sign is difficult to be transported, and only the developer 28 charged normally is selected and contributes to development.

Therefore, the developing roller 29 is coated with the uniformly charged developer 28, and a high quality image can be obtained. Here, the thickness of the developer 280 layer on the surface of the coated developing roller 29 is greater than a predetermined thickness, and there is some variation. Next, developing roller 2
When the charged developer 28 on the surface of the developing roller 29 passes through the elastic blade 47, a part of the developer 28 is scattered by the elastic blade 47 to a predetermined layer thickness, that is, about 40 μm (the layer thickness at this time is 10 μm). ~70 μm is desirable). The end face of the elastic blade 47 is finished with a straightness of 0°15 mm or less, and the mounting position is as shown in FIG. Since the surface 47B is provided in pressure contact with the developer roller 29, the layer thickness and charge amount of the developer 280 on the developer roller 29 become uniform.

Further, the linear pressure of the elastic blade 47 in the axial direction of the developing roller 29 can be kept constant by bonding the flat surface 47B of the elastic blade 47 on the opposite side to the pressure contact portion to the mounting member 63, as shown in FIG. Can be done. Furthermore, adjustment screw 64A,
64B allows fine adjustment of the linear pressure of the elastic blade 47, making the layer thickness and charge amount of the developer 28 more uniform. As a result, a high-quality image without density unevenness can be obtained.

Next, the position of the elastic blade will be explained in more detail based on FIG. 6. The position of the surface 47B including at least the downstream edge 47A of the elastic blade 27 with respect to the moving direction of the developing roller 29 is the nip when the edge 47A of the elastic blade 47 does not come into contact with the surface of the developing roller 29, as shown in FIG. This is the position where a surface 47B occurs and an edge 47A is provided within the range of the nip surface 47B. The developer 28 that has come into contact with the elastic blade 47 falls onto the fur brush 30 while moving from the center of the developing roller 29 toward both ends. By rotating the spiral fur brush 30, the fur brush 30 moves from both ends to the center.

Therefore, the developer 28 near both ends of the developing roller 29 and the fur brush 30 does not increase, and the height of the developer 28 in the storage section 35 is kept constant. Furthermore, first sealing material 48.49 and second sealing material 50. 51 and elastic seams) 52 and 53, the outer peripheral surface 29a of the developing roller at both ends is
, 29b, so that the developer 28 moving to both ends of the developing roller 29 does not scatter or leak. That is, the present developing device can uniformly charge the developer 28 on the developing roller 29-1 and make the layer thickness uniform, and furthermore, there is no scattering or leakage of the developer 28, and there is no fogging or density unevenness. High quality images can be obtained.

Next, when the negatively charged electrostatic latent image on the photosensitive drum 22 faces the positively charged developer 28 on the developing roller 29, the developer 28 is blown away by the electrostatic force of the electrostatic latent image on the photosensitive drum 22. The latent image can then be developed. Surplus developer 28 that was not used for development is transferred to the developing roller 2.
While remaining attached to 9-L, it is carried further downstream and passes through the leak prevention sheet 58. At this time, since the leak prevention sheet 58 is in light contact with the developing roller 29, the developer 28 is carried directly into the housing 33 by electrostatic adhesion, and after passing through the leak prevention sheet 58, it is returned to the outside. It won't leak.

Next, the developer 28 adhering to the surface of the developing roller 29
The history of the developing roller 29 is erased by scraping it off with the fur brush 30. Therefore, a high-quality image without ghosts can be obtained.

The developer 28 scraped off by the fur brush 30 is conveyed by the fur brush 30 and then scraped off by the scraping plate 42 and returned to the storage section 35 through the opening 41.
The developer 28 on the developer roller 29 is not overcharged.

Therefore, high-quality development is possible. In this developing state, the developer 28 is present in the storage section 35, so when the second supply means 36 supplies the developer 28, the partition plate 44
When the developer 28 accumulates on the partition plate 40, the remaining amount detecting means 62 detects that the developer 28 is present. Then the second
The supply means 36 repeats the development process and supplies the storage section 35.
Even if the amount of developer 28 in the opening 41 decreases, the sheet-like elastic member 39 rotates clockwise and is displaced as shown in FIG. It can be fed into the fur brush 30. Therefore, even if the bottom surface of the storage section 35 is made horizontal, the developer 28 in the storage section 35 can be supplied to the fur brush 30 without any problem. Furthermore, since the developer 28 is stirred within the storage section 35 by a sheet-like elastic member 39, there is an effect that the height of the developer 28 within the storage section 35 is kept constant. Next, storage section 3
Since the developer 28 does not accumulate between the partition plate 44 and the partition plate 40 when the developer 28 runs out in the remaining amount detection means 6.
2, it is detected that there is no developer 28. Note that since the developing roller 29 and the photosensitive drum 22 have the same circumferential speed, it is possible to eliminate edge effects when developing a latent image.

In this developing device, since the developer is not directly supplied to the developing roller by the partition plate, uncharged developer does not adhere to the developing roller. Further, since the charged developer on the developing roller is returned to the developer storage means by the circulation means, there is no overcharged developer on the developing roller. Therefore, high-quality development is possible. Further, since one fur brush can supply the developer to the developing roller and scrape off the developer on the developing roller after development, the configuration can be simplified and the device can be made smaller.

In addition, since the structure is such that there is no developer leakage or scattering, restrictions on the arrangement of the developing device can be expanded.

In this example, an example was explained in which regular development (positive-positive development) in an electrophotographic copying machine was tested, but it goes without saying that the present invention can also be applied to reversal development (negative-positive development) in a laser printer or the like. stomach.

In addition, the present invention is well suited to non-magnetic component developers, and by configuring the charge carrier and the developer carrier in a non-contact manner, the present invention enables color development in which multiple color developers are layered on the charge carrier. It also becomes possible to form images.

As described in detail, the developing device of the present invention has one end of a plate-shaped elastic blade pressed against the outer circumferential surface perpendicular to the rotating direction of the developer carrier, and at least the thickness side plane excluding the pressed portion is connected to the housing. It is characterized by being bonded to a mounting member provided on the developer carrier, which allows the linear pressure perpendicular to the direction of rotation of the developer carrier to be kept constant, and the formation of a thin layer and the amount of charge on the developer carrier to be uniform. . As a result, high-quality development becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a developing device according to a first embodiment of the present invention, FIGS. The figure is a cross-sectional view of the main part of the developing device in the first embodiment of the present invention.
The figure is a sectional view of a main part of a conventional developing device using a one-component developer, and FIG. FIG. 2 is a perspective view of the device. 28...Developer, 29...Developer carrier, 33...
- Housing, 47... Elastic blade, 63... Mounting member. Agent's name Patent attorney Toshio Nakao 1 name a - Current member a - Sakaiminato IPJ hemorrhoid holder toggle body 47 - Elastic blade 63 - Installation 115 # 1st rl! J Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 U

Claims (1)

[Scope of Claims] (1) Includes a rotating endless developer carrier and a plate-shaped elastic blade that regulates the developer to a predetermined layer thickness;
One end of the elastic blade is pressed against the outer circumferential surface perpendicular to the rotating direction of the developer carrier, and at least the flat surface on the thickness side excluding the pressed portion is adhered to a mounting member provided on the casing. (2) The developing device according to claim 1, wherein at least the pressure contact portion of the elastic blade is a surface including at least an edge on the downstream side of the elastic blade with respect to the moving direction of the developer carrier. (3) Consisting of a first supply means for supplying developer to the developer carrier, and a second supply means provided in the developer storage means for supplying the developer to the first supply means, 2. The developing device according to claim 1, further comprising a circulation means through which the developer flows in and out between the first supply means and the second supply means. (4) A developing device according to claim 1, wherein a sheet-like elastic body is provided to surround the outer peripheral surface of both ends of the developer-carrying member, and the elastic blade is pressed against the developer-carrying member through the sheet-like elastic body. Device. (5) A first sealing material for the developer that surrounds the outer circumferential surface of both ends of the developer carrier, and a second sealing material that shields the space at the joint between the developer carrier and the first sealing material of the elastic blade. 2. The developing device according to claim 1, comprising: (6) The developing device according to claim 3, further comprising a partition plate provided between the developer carrier and the second supply means at a position where the developer in the developer storage means is not directly supplied to the developer carrier. (7) The developing device according to claim 3, wherein the circulation means is constituted by a partition plate having an opening through which the developer flows in and out between the first supply means and the second supply means. (8) According to claim 3, wherein the second supply means is constituted by a rotating blade, and the blade is configured to rotate from bottom to top with respect to the first supply means, and to supply the developer to the first supply means. The developing device described. (9) The first supply means is composed of a cylindrical elastic body, and the excess developer on the elastic body is scraped off by sliding contact with the cylindrical elastic body, and the developer on the elastic body is scraped to make the developer uniform on the elastic body. 4. The developing device according to claim 3, further comprising a plate. (10) The first supply means is composed of a cylindrical elastic body, and the developer carrying member and the cylindrical elastic body are brought into contact with each other, and at the contact position, the developer carrying body and the cylindrical elastic body are moved in the forward direction. 4. The developing device according to claim 3, wherein the circumferential speed of the cylindrical elastic body is faster than the circumferential speed of the developer carrier. (11) The first supply means is constituted by a cylindrical elastic body, and the first supply means is located upstream from a position where the developer carrier and the cylindrical elastic body face each other with respect to the moving direction of the cylindrical elastic body, and the developer A spill prevention means for preventing developer from spilling is provided below the carrier, and the spill prevention means is fixed to a U-shaped developer leak prevention member, one end of which is fixed to the leak prevention member, and the other end of which is fixed to the developer carrier. and a developer elastic leak prevention sheet that lightly contacts the surface of the developer carrier. 4. The developing device according to claim 3, wherein the developing device is provided upstream of a line connecting the center of the cylindrical elastic body.