JPH03144470A - Developing device - Google Patents

Abstract

PURPOSE:To stably keep a gap between a photosensitive drum and a developing roller by coating the outer peripheral plane of both ends of the developing roller with resin containing a lubricant, and performing integral working so as to keep the prescribed gap of a step between the surface of the developing roller and that of the resin. CONSTITUTION:The outer peripheral plane of both ends of the developing roller 29 is coated with the resin containing the lubricant as a supporting means 30 to support the gap between an image holding body and the developing roller 29, and also, the integral working of the developing roller 29 with the resin 30 is performed so as to keep the prescribed gap of the step between the surface of the developing roller 29 and that of the resin 30. Thereby, it is possible to keep the gap between the photosensitive drum 22 and the developing roller 29 constant, and also, to electrify a developer 28 on the developing roller 29 uniformly, and also, to uniformize layer thickness, and furthermore, no splash or leakage of the developer 28 occurs. Therefore, an image without generating fogging and density nonuniformity and with high definition can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a developing device for forming images such as a copy number printer using electrophotography, and is related to conventional technology. As one method for carrying out the
Photosensitive drum 1 on which an electrostatic latent image is formed like 8773
Press the resin spacer rollers 3A and 3B that rotate on the axes at both ends of the developing roller 2, and! A predetermined gap was maintained between the optical drum 1 and the developing roller 2, and the electrostatic latent image on the photosensitive drum 1 was developed with the developer uniformly adhered to the developing roller 2. If the gap between the developing roller 2 and the roller 2 is not constant, uneven development will occur, making it difficult to reproduce high-quality images. The power is transmitted from a drive gear 4 provided on the drum 1 side to a gear 5 provided on the axis of the developing roller.

Problems to be Solved by the Invention Therefore, in the above configuration, the gap between the image carrier and the developing roller varies. The causes of this variation are as described below.

(1) The outer circumferential surface of the developing roller and the outer circumferential surface of the developing roller, and the deflection of the outer circumferential surface of the developing roller with respect to the developing roller shaft. ．． Accuracy of photosensitive drum cylindricity, etc. (2) Spacer rollers and developing roller kneading that occur during pressing
For example, regarding distortion (above), the difference in the pressing force applied to each spacer roller provided at both ends of the developing roller
The force generated when the driving gear and the developing roller gear engage and rotate causes distortion to change, and the gap between the LM optical drum and the developing roller to become unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that solves these conventional problems and forms high-quality images.

Means for Solving the Problems (1) The present invention (top)
The support means is provided with a supporting means for supporting the image carrier and the developing roller at a predetermined gap, and the supporting means coats the outer circumferential surface of both ends of the developing roller with a resin containing a lubricant, and the step between the developing roller surface and the resin surface is arranged in the predetermined gap. This is a developing device in which a developing roller and resin are integrally processed.

(2) The present invention also includes supporting means installed at both ends of the developing roller, sandwiched between the image bearing member and the developing roller, and supporting the image bearing member and the developing roller with a predetermined gap, the supporting means being made of metal as a base material. This is a developing device made of nanocomposite material.

action The effect of this technical means is as follows.

(1) By forming supporting means with a resin containing a lubricant on the outer peripheral surface of both ends of the developing roller, the surface of the photosensitive drum is prevented from being scratched, and the level difference between the developing roller surface and the resin surface is formed to have a predetermined gap. This reduces the thickness of the resin and reduces distortion caused by pressing force.

Furthermore, by integrally processing the developing roller and the resin, it is possible to reduce the runout accuracy of the developing roller and the supporting means, and improve the level difference accuracy between the developing roller and the resin surface. By supporting the predetermined gap and forming the support means from a nanocomposite material with a metal matrix, the external shape and deflection accuracy of the support means are improved.
Moreover, distortion due to pressing force is reduced.

Its viscosity can maintain a predetermined gap with high precision,
High-quality development becomes possible.

EXAMPLE An example of the present invention will be described below. 1 to 4 show a first embodiment of the present invention, which is an example used in an electrophotographic copying machine. In FIG. In the embodiment, the image carrier 22 is a photoconductor drum having a photoconductor 24 made of selenium oxide, an organic photoconductive material, etc. supported on the surface of a cylindrical aluminum base 23 (therefore, hereinafter referred to as image carrier (The body 22 is referred to as a photosensitive drum 22). The cylindrical shape of the base 23 is such that the cylindricity is suppressed to 10 μm or less and the rotational speed fluctuation of the photosensitive drum 22 is suppressed to 2 when processing the outer peripheral surface of the base 23.
Even if the cylinder thickness t is set to be suppressed to ~5% or less, it is preferable that the cylinder thickness tL is 6 mm or more. By setting this thickness, the cylindricity processing accuracy of the base 23 is improved. 4 25 is a charger The first DC high-voltage power supply 26 charges the entire surface of the photoconductor 24 depending on the photoconductor 24 on the photosensitive drum 22, for example, by applying a negative corona in the case of zinc oxide and a positive corona in the case of selenium. &
Reference numeral 27 schematically shows an optical section that projects a pattern light image onto the photosensitive drum 22 to form an electrostatic latent image.

28 is a developer, which is an ordinary insulating toner with a certain resistance.
The developer 28 may be magnetic toner or non-magnetic toner (12
9 is a developing roller, and for example, a metal roller such as a stainless steel mirror or aluminum, or a roller whose surface is coated with resin is used.For example, as shown in FIG.
As shown in FIG. 2, the outer circumferential surfaces 29a and 29b at both ends are smooth, and the center surface 29c is a rough surface with minute irregularities. 30 is a support means, which takes into consideration damage to the surface of the photosensitive drum 22. For example, fluororesin 30a, 3 containing a lubricant
The smooth surfaces 29a and 29b of the developing roller 29
The developing roller 29 and supporting means 30a and 30b at both ends are integrally processed so that the level difference between the surface of the developing roller 29c and the resin surface of the supporting means is a predetermined gap. Furthermore, in order to reduce surface wear of the supporting means 30a, 30b and the photosensitive drum 22, the supporting means 30a, 30b and the photosensitive drum 22 may be moved in the forward direction at the developing position, and the circumferential speeds of their respective outer peripheral surfaces may be made approximately equal. Reference numeral 31 indicates a groove, which prevents the developer 28 from moving towards both ends of the developing roller 29 and prevents it from adhering to the resin surface of the supporting means 30a, 30b.32 indicates the developer 28.
This is an elastic roller that supplies the image to the developing roller 29. The elastic roller 32 is made of an elastic material such as a fur brush or sponge. In this embodiment, the elastic material is made of conductive fur using carbon-containing rayon fiber. Further, the fur brush 32 is surrounded by a developing container 33.
It is in sliding contact with the surface of the developing roller 29 and rotated, for example, in a clockwise direction. Reference numeral 34 denotes a developer storage means, which is composed of a storage section 35 that stores the developer 28 and a supply means 36 that supplies the developer to the fur brush 32. Further, the storage section 35 has an opening 37 for replenishing the developer 28 at one end, and is formed by a part of the developer container 33 . Ma? , the supply means 36 is a mandrel 38
One end of a sheet-like elastic member 39 made of polyethylene terephthalate or the like with a thickness of approximately 30 to 80 μm is fixed to the outer peripheral surface of the developer 28 by rotating or distributing the mandrel 38.
is supplied to the fur brush 32. In this embodiment, the mandrel 38 rotates clockwise. 40 is a partition plate which is a circulation means, and a fur brush 32 and a supply means 36
The opening 41 is installed between the fur brush 32 and the supply means 36, and has an opening 41 through which the developer 28 flows in and out between the fur brush 32 and the supply means 36.

A scraping plate 42 is formed as a part of the developer container 33 and comes into contact with the fur brush 32 to equalize the amount of developer 28 in the fur brush 32 and scrape off overcharged developer 28 in the fur brush 32. Reference numeral 43 is a lid for the replenishment opening 37. 44 is a developer reservoir, and the developer roller 2
The developer reservoir 44 provided on the fur brush 32 has a capacity capable of supplying a predetermined amount of the developer 28 to the fur brush 32. As shown in FIG. 2, 45 is a bearing for the developing roller 29, and 46 is a bearing for the fur brush 32. Reference numeral 47 denotes a layer thickness regulating member for regulating the layer thickness of the developer 28, and in this embodiment, a plate-shaped elastic blade made of urethane rubber is used. It may be made of a certain synthetic resin, or an elastic metal such as phosphorescent spring steel, or an elastic metal or synthetic resin coated with a fluororesin. In addition, the width ζ of the elastic blade 47 should be at least long enough to contact the outer circumferential surfaces 29a and 29b at both ends of the developing roller 29, as shown in FIG. Both end outer peripheral surfaces 29a and 29b of the roller 29
The resin surface of the support means 30a, 30b is surrounded and closely contacted to block the developer 28 moving to both ends 29a, 29b, and to remove the developer 28 adhering to the resin surface of the support means 30a, 30b. Mr. Monode Elastic side seal member 48. 49? , t, For example, 'a'& It is made of an elastic material such as nonwoven fabric (felt), sponge, or rubber. 50.51 is the developing roller 29
A sealing material that shields the space between the side seal members 48 and 49 and the elastic blade 47, such as sponge,
It is made of elastic material such as rubber. 52,531&
This is a blocking means that blocks the developer 28 moving to both ends of the developing roller 29 and prevents the developer 28 from reaching the supporting means 30a and 30b.Although an elastic sheet is used in this embodiment, an elastic sheet 52, 53 (for example, 40- Made of elastic material such as 150 μm polyethylene terephthalate or metal t7.
t. One end is attached to the side seal member 48.49, the other end is made to protrude downstream from the blade edge 47A with respect to the rotational direction of the developing roller 29, and the seal member 50.51 is attached between the developing roller 29 and the sealing member 50.51. It is set up. (resistance elastic sea)
Thickness of 52, 53 (friend-sensitive drum 22 and developing roller 29)
The height from the surface of the developing roller 29 is made smaller than that of the supporting means 30a, 30b in order to maintain a stable gap between the developing roller 29 and the supporting means 30a, 30b.

54.55 is the elastic blade 47 with respect to the developing roller 29.
The elastic blade 47 is a presser plate spring that improves the adhesion of the elastic blade 47.
Through the sealing material 50.51 and elastic sheet 52.53
It is installed by pressing the button. Reference numeral 56 denotes a spill prevention means for the developer 28 that seals the gap A between the developing roller 29 and the developing container 33, and is located upstream from the position where the developing roller 29 and the fur brush 32 face each other in the direction of movement of the fur brush 32 and for developing. Even if it is provided below the roller 29, the spill prevention means 56 includes a U-shaped leak prevention member 57 and an elastic 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 wax 29. It consists of However, one end of the leak prevention sheet 58 of the spill prevention means 56 may be provided on the developer container 33. The gap between both ends of the leak prevention sheet 58 in the width direction and the developer container 33 is at the bottom of the side seal member 48, 49. It is sealed. As shown in FIGS. 2 and 4, the side seal members 48° and 49 are
The leak prevention sheet 5 is in pressure contact with the developing roller 29 via the leak prevention sheet 58 and is in light contact with the surface of the developing roller 29.
8 is provided so as not to be located on the contact surface between the developing roller 29 and the fur brush 32. The leak prevention sheet 58 is made of an elastic material such as polyethylene terephthalate or urethane rubber.
Leakage prevention member 5
7 is made of metal such as stainless steel or aluminum, and even if the developer 28 leaks from the gap between the developing roller 29 and the leak prevention sheet 58, the receiver is also stopped so that it does not fall downward. In this case, the leak prevention sheet 58 Developer by 28
Since the leakage is almost completely stopped, the capacity of the leakage prevention member 57 is small.As shown in FIG.
A voltage is applied between the developing roller 29 and the fur brush 32 to adjust the layer thickness of the charged developer 28 on the surface of the developing roller 29.The fur brush 32 is made of a conductive material. , has the function of preventing overcharging of the frictionally charged developer 28 on the developing roller 29 and making the potential uniform. Therefore, the fur brush 32 has a specific resistance of about 1011 Ωcm or less, preferably 10'ΩCf1l.
It is better to use a conductive material of io'Ωcrn (1
In addition, as the fur brush 32, other conductive fibers may be used instead of just conductive rayon fibers as in this example, and a fur brush made by electrostatic flocking may be used to make the coating uniform. It is also effective. 61c;L A pressure contact spring that presses the resin surface of the support means 30a, 30b against the photosensitive drum 22, and the developer container 33
The operation of the developing device of the first embodiment, which is provided at both ends of the developing device and configured as described above, will be explained. As a condition for carrying out the implementation, the photoconductor 24 on the photosensitive drum 22 and the oxidized sub-resistance roller 32 contain carbon and have a specific resistance of about 10.
The fur brush has 3,600 rayon fibers of 6 Ωcm/approximately 112 Cl, and the surface roughness of the developing roller 29 is 5.
μm Rmax, the linear pressure of the elastic blade 47 in pressure contact with the developing roller 29 is 25 g/ca, the resin thickness at both ends of the developing roller 29 is tao, 1 m @, leak prevention sheet 5
8 is a urethane sheet with a thickness of 1100 A1, and photosensitive drum 2
The pressing force W of the pressure contact springs 61 and 62 that press the pressure springs 61 and 62 is 3 kg each.
In FIG. 1, the developer 28 is an ordinary positively charged non-magnetic one-component toner, and the charger 25 is connected to a first high-voltage DC power supply 26.
By applying a high voltage of about -6 kV, the entire surface of the photosensitive drum 22 is negatively charged to about -600 V by a negative corona.Next, the optical section 27 illuminates the negatively charged photosensitive drum 22 with a halogen lamp or the like to reflect the original. When the image (pattern light image) is projected, the portion corresponding to the non-image area of the document on the photosensitive drum 22 is almost opaque due to the reflected light.
The static electricity is removed to a residual potential close to V and a positive electrostatic latent image is formed. Meanwhile, the developer 28 in the storage section 35 is uniformly supplied to the developer reservoir 44 through the opening 41 by the sheet-like elastic member 39. Next, even if the uniformly supplied developer 29 is supplied into the fur brush 32, the excess developer 28 in the fur brush 32 is scraped off by the scraping plate 42, and an appropriate amount is supplied. 42 and the developing container 33. Next, the charged developer 28 in the fur brush 32 generates an electric field between the developing roller 29 and the fur brush 32, and the surface of the developing roller 29 is charged. At the time of coating the developer 28, a voltage of about 0 to 250 V is applied from the second DC high voltage power supply 60 to adjust the layer thickness. Also, by applying this voltage, the developer 2
8 is transferred from the fur brush 32 to the developing roller 29. For example, even if there is uncharged developer 28 or developer 28 charged with the opposite sign in the developer 28, the uncharged developer 28 and the developer 28 charged with the opposite sign are transferred. Only the developer 28 that is less likely to be charged and that is normally charged is selected and contributes to the development. Therefore, the developing roller 29 is coated with the uniformly charged developer 28, making it possible to obtain a high-quality image. Here, the layer thickness of the developer 28 on the coated surface of the developing roller 29 is greater than a predetermined thickness, and there is some variation.
When the charged developer 28 on the surface of the developing roller 29 passes through the elastic blade 47, a part of it is scraped off by the elastic blade 47, resulting in a predetermined layer thickness of about 40 μm (the layer thickness at this time is 10 μm). The developer 28 that has come into contact with the elastic blade 47 then falls onto the fur brush 32 while moving from the center of the developing roller 29 toward both ends. The developer 28 has moved toward both ends of the developing roller 29.The side seal members 48, 49, sealing materials 50, 51, and elastic sheets 52, 53 surround the outer peripheral surfaces 29a and 29b of the developing roller at both ends in a sealed structure. Iruta△ Splashing or leaking Shinahachi Developer 2
8 should move to the outer circumferential surfaces 29a, 29b at both ends of the developing roller, it can be prevented by the L groove 31, and the supporting means 30a,
Also, since the support means 30 is provided at both ends of the developing roller 29 and the thin support means 30a and 30b are provided, the pressure contact spring 61
, 62 can be greatly reduced. Therefore, the gap between the photosensitive drum 22 and the developing roller 29 can be kept constant. Furthermore, the leak prevention sheet 58 prevents the developer 28 from leaking from the gap between the side surfaces of the side seal members 48 and 49 and the developer container 33. The gap can be kept constant, the developer 28 on the developing roller 29 can be charged uniformly, and the layer thickness can be made uniform, and the developer 28 can be prevented from scattering or leaking (1). However, 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 transferred onto the photosensitive drum 22. The latent image can be developed by flying due to the electrostatic force of the electrostatic latent image.
The developer 28 remains attached to the surface of the developing roller 29 and is carried further downstream and passes through the leak prevention sheet 58. The leak prevention sheet 58 is in slight contact with the developing roller 29. After passing through the leakage prevention sheet 58, the developer 28 of the developing roller 29 is scraped off by the fur brush 32 and conveyed.
The developer 28 transported by the developer roller 29 is scraped off by the scraping plate 42 and returned to the storage section 35 through the opening 41. The developer 28 is stirred in the storage section 35 by a sheet-like elastic member 39, which makes it possible to develop images of high quality. A second embodiment of the present invention will now be described, in which the circumferential speeds of the developing roller 29 and the photosensitive drum 22 are made almost the same, thereby making it possible to eliminate the edge effect when developing a latent image. .

FIG. 5 shows a second embodiment of the present invention in which the developing roller 29 is made of aluminum metal. 29
In this structure, the supporting means 30a, 30b are rigid bodies, and the outer shape and Machining accuracy such as run-out can be improved, and distortion caused by fluctuations in the pressing force of the pressure spring 61 and the like can be reduced. Furthermore, the developing roller 29 and the supporting means 30a, 30b are made of the same material (having the same coefficient of linear expansion), so there is no gap variation due to temperature changes. Furthermore, the developing roller 29 and supporting means 30a, 30b
By integrally machining these, the machining accuracy of the external shape and runout, etc., is improved.

This tone can maintain a predetermined gap with high precision,
High-quality development becomes possible.

Furthermore, as shown in FIG. 6, the surface of the developing roller 29 is also made of a nanocomposite material, so that the electrode 29d of the developing roller 29 and the developer 28 on the developing roller 29 are easily separated. The developer 28 can stably fly onto the photosensitive drum 22 and high-quality development is possible.Next, a third embodiment of the present invention will be described. FIG. 7 shows a third embodiment of the present invention. Base 2 of photoreceptor drum 22
3ζ The support means 30e and 30f made of aluminum metal and made of a nanocomposite material with aluminum metal as a matrix are press-fitted into the base 23.
The surface of the support means 30e, 30f is integrally processed so that the level difference between the surface and the surface of the support means 30e, 30f is a predetermined gap.This improves the machining accuracy of the outer shape and runout of the support means 30a, 30b, and prevents exposure to light due to temperature changes. Fluctuations in the gap between the drum 22 and the developing roller 29, the pressure contact spring 61,
The effect of distortion caused by fluctuations in the pressing force of 62 can be greatly reduced, and a predetermined gap with high accuracy can be maintained.
High-quality development is possible Next, we will explain the fourth embodiment of the present invention. Figure 8 shows the fourth embodiment of the present invention, which relates to reversal development (negative-positive development) in laser printers, etc. However, the developing roller 29 is made of aluminum metal, and support means 30a and 30b made of an insulating material are provided at both ends of the developing roller 29.As is well known, in the case of reversal development (between the photosensitive drum 22 and the developing roller 29) An application means 64 for applying a voltage to is required. In such a configuration, - on the insulator surface of the support means 30a, 30b between the surface of the image carrier 22 and the surface of the developing roller 29 shown by the dotted chain line; If the minimum creepage distance is short, there is a problem that electric discharge occurs between the photosensitive drum 22 and the developing roller 29 through the creeping portion especially at high temperatures, causing uneven discharge on the image. The voltage X (k
V) ratio: X/L (kV/mm) is 1 (kV
/rnm) or less, it is confirmed that there is no problem with discharge, and no discharge occurs.As shown in FIG.
52b, the structure is simple, and there is no problem of the above-mentioned discharge or adhesion of the developer 28 to the supporting means 30a, 30b (1) The present invention is not limited to the four embodiments described above. A composite configuration of each element is also possible.

In addition, the present invention is well suited to a developing method in which the image is developed without contact between the developing roller and the image bearing.
It is also possible to form a color image by superimposing and developing multiple color developers on an image carrier.As described in detail, the structure of the present invention allows the gap between the image carrier and the developing roller to be formed with high precision. Even though it can be retained, its electrical formation makes it possible to develop high-quality images without uneven density.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 shows a cross section of the main parts of a developing device according to a first embodiment of the present invention, and FIGS. 2 to 4 show the configuration of each part of a developing device in the same embodiment. The figure is a perspective view of the main part of the developing device according to the second embodiment of the present invention @ Fig. 6 is a cross section of the main part of the developing device according to the second embodiment of the present invention Figure 7 is the third embodiment of the present invention The cross section of the main part of the developing device in
Fig. 8 is a cross section of the main part of the developing device according to the fourth embodiment of the present invention & Fig. 9 is a perspective view of the main part of the developing device according to the fourth embodiment of the present invention @ Fig. 10 is the main part of the developing device according to the conventional example It is a sectional view of the main part. 22... Image bearing member 28... Before development 29... Development roller, 30... Supporting method 31... Mount 33
...Development system tL...Shortest creepage distance contact 48, 49...
side seal et al.

Claims (14)

[Claims] (1) Supporting means is provided between the image bearing member and the developing roller and supporting the image bearing member and the developing roller with a predetermined gap, and the supporting means includes a lubricant contained on the outer circumferential surface of both ends of the developing roller. A developing device in which the developing roller and the resin are coated with a resin and integrally processed so that the level difference between the developing roller surface and the resin surface is the predetermined gap. (2) Supporting means installed at both ends of the developing roller, sandwiched between the image bearing member and the developing roller, and supporting the image bearing member and the developing roller with a predetermined gap, the supporting means being made of metal. A developing device made of nanocomposite material as a base material. (3) The developing device according to claim 2, wherein the developing roller is made of a metal material. (4) Supporting means is provided between the image bearing member and the developing roller and supporting the image bearing member and the developing roller with a predetermined gap, and the supporting means is made of a nanocomposite material having a metal matrix. and installed integrally with both ends of the image carrier or the developing roller, and integrally processed so that the level difference between the surface of the image carrier or the developing roller and the surface of the support means is the predetermined gap. Developing device. (5) The developing device according to any one of claims 1 to 4, wherein the image bearing member and the supporting means are moved in the forward direction at the developing position, and the circumferential speeds of the image bearing member and the supporting means are approximately equal. (6) An insulating support means installed at both ends of the developing roller, sandwiched between the image carrier and the developing roller, and supporting the image carrier and the developing roller with a predetermined gap; and an axial center of the developing roller. A developing device including a groove provided at a boundary between the developing roller surface and the supporting means in the direction of the direction. (7) An insulating support means provided at both ends of the developing roller and sandwiched between the image carrier and the developing roller to support the image carrier and the developing roller with a predetermined gap; an application means for applying a voltage, and the ratio of the voltage of the application means to the shortest creepage distance on the insulator surface of the support means from the surface of the image carrier to the surface of the developing roller is set to a value at which no discharge occurs. The set developing device. (8) An insulating support means provided at both ends of the developing roller, sandwiched between the image carrier and the developing roller, and supporting the image carrier and the developing roller with a predetermined gap; a blocking means for blocking the moving developer and preventing the developer from reaching the supporting means, and the height from the developing roller surface to the supporting means surface is higher than the height from the developing roller surface to the blocking means surface. developing device. (9) The developing device according to claim 8, wherein the supporting means and the blocking means provided at both ends of the developing roller are integrally formed. (10) Insulating support means installed at both ends of the developing roller, sandwiched between the image carrier and the developing roller, and supporting the image carrier and the developing roller with a predetermined gap; and a side seal member made of an elastic body that tightly surrounds the outer peripheral surface of the support means. (11) An insulating support means provided at both ends of the developing roller, sandwiched between the image carrier and the developing roller, and supporting the image carrier and the developing roller with a predetermined gap; and one end fixed to the developer container. and a leak-preventing sheet made of an elastic material whose other end lightly contacts the outer circumferential surface of the developing roller to seal the gap between the developing roller and the developing container; A developing device comprising an elastic side seal member that tightly surrounds the outer peripheral surface of the support means and both ends of the surface of the leak prevention sheet. (12) A developing device in which the developing roller is formed of a nanocomposite material having a metal matrix. (13) The image carrier includes a cylindrical image carrier and a developing roller carrying a developer, and the shape of the cylindrical portion of the image carrier is such that the cylindricity is suppressed to 10 μm or less during processing of the outer peripheral surface of the image carrier. The developing device has a cylindrical thickness that allows the image carrier to maintain a predetermined rotational speed fluctuation. (14) an insulating support means integrally formed on both ends of the developing roller, sandwiched between the image bearing member and the developing roller, and supporting the image bearing member and the developing roller with a predetermined gap;
A developing device that moves an image carrier and a supporting means in a forward direction at a developing position, and is provided with a layer thickness regulating means for regulating the developer to a predetermined layer thickness on the developing roller on the upstream side as viewed from the developing position. .