JPH04208961A - Developing device - Google Patents

Abstract

PURPOSE:To fully electrostatically charge a developer and to eliminate the irregularity of image density and the fogging of a non-image part by installing a developer thin layer forming means provided with a laminated body where a conductive layer and an elastic layer are laminated from a side opposed to a developing roller on a supporting member. CONSTITUTION:A developer thin layer forming blade 110 is obtained by attaching a chip 110b to a flat spring 110a and further attaching a sealing material 110c made of urethane foam to the spring 110a. The sealing material which is thicker than the chip 110b is used as the sealing material 110c. When the chip 110b is made to press-contact with the developing roller 109, the movement of the developer toward both ends of the roller is surely sealed. Since the sealing material 110c is arranged to cover the tip part of the blade 110, the peeling caused by carrying the developer is prevented, the life of the blade is prolonged, and stable sealing is accomplished. The chip 110b is mounted on the spring 110a on the blade 110, so that the developer layer without unevenness is easily and surely formed by the elasticity of the spring 110a.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device for visualizing a latent image in an electrophotographic device or an electrostatic recording device.

(Prior art) One of the developing methods using a one-component developer is the pressure development method (Ig+pressure development method).
t) is known. This method is characterized by contacting the electrostatic latent image with the developer particles or developer carrier at substantially zero relative peripheral velocity (U.S. Pat.
2,012, 3,731,148, Japanese Unexamined Patent Publication No. 47-13
088, 47-1308.9, etc.) Since no magnetic material is required, the device can be simplified and downsized, and it has many advantages, such as the ability to easily color the developer.

In the pressure development method, development is performed by pressing or bringing the developer carrier into contact with the electrostatic latent image, so it is necessary to use a developing roller having elasticity and conductivity. Particularly when the electrostatic latent image holder is a rigid body, it is essential that the developing roller be made of an elastic body to avoid damaging it. Furthermore, as is well known, in order to obtain a developing electrode effect or a bias effect in the developing roller, it is desirable to provide a conductive layer on or near the surface of the developing roller and apply a bias voltage as necessary. Furthermore, since the charge is applied to the developer by frictional charging between the developing roller and the developer layer forming blade, it is possible to ensure a constant nip width by bringing the developer layer forming blade into pressure contact with the developing roller. is necessary.

In order to impart a sufficient charge to the developer, it is desirable to use a triboelectrification type material that matches the polarity of the charge. In particular, in the so-called reversal development method used in laser printers, digital PPCs, etc., in which the photoreceptor is negatively charged and development is performed with a developer charged with the same polarity, the developer is charged with a negative charge. Silicone rubber, which is easily charged with electricity, is often used. However, with silicone rubber, the tip of the blade tends to wear out over time, which causes the problem that the shape changes drastically.

FIG. 2 is a schematic diagram showing the developing roller and the tip of the blade provided on the developing roller. As shown in Figure 2,
A developer thin layer forming blade 110 consisting of a thin plate spring material 110a and a tip 110b formed at the tip of the thin plate spring material 110a is placed on the developing roller 109 so that the tip 110b comes into pressure contact with the surface of the developing roller 109. It is located. Assuming that the space formed by the developing roller 109 and the chip 110b is a space F as shown in FIG. 2, if the space F becomes narrower due to wear of the chip,
The amount of developer that enters the chip changes, and the amount of charge and layer thickness of the developer change. As a result, image defects such as density unevenness, deterioration of density followability of solid images, and fogging in non-image areas occur in the resulting images, and development efficiency increases due to the lower charge amount, which reduces developer consumption. Problems such as a significant increase occur.

Therefore, it may be possible to use a urethane rubber or the like which has relatively little wear even though it has poor charging properties so that the influence of wear can be ignored.

However, when using such urethane rubber,
Since the amount of charge of the toner is low, there is a problem with reliability in a humid environment, and a problem arises in that good images cannot be stably obtained.

(Problems to be Solved by the Invention) The present invention has been made to solve the problems of the prior art as described above. A developer forming means is provided for obtaining a developing device that can obtain high-quality images without images, and that does not cause changes in developer layer thickness, increase in developer consumption, or deterioration of images even during long-term use. The purpose is to provide.

[Structure of the Invention (Means for Solving the Problems)] The developing device of the present invention brings a thin layer of developer formed on a developing roller close to or in contact with an image carrier disposed opposite to the developing roller. A developing device that visualizes a latent image by making a latent image visible, comprising: a support member; and a laminate formed on the support member, in which a charged layer and an elastic layer are laminated from the side facing the developing roller. It is characterized by comprising a layer forming means.

Preferably, the charging layer has a charging property opposite to that of the toner.

(Function) Since the developer thin layer forming means of the present invention causes very little wear on the tip of the blade, it is possible to impart sufficient charge to the toner. Further, by using this developer thin layer forming means, it is possible to obtain a high-quality image without defective images such as uneven image density and fog in non-image areas,
Moreover, such high-quality images can be obtained for a long period of time.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1(a) is a perspective view showing one embodiment of the developer thin layer forming blade according to the present invention, and FIG. 1(b) is this A-A.
It is a sectional view in a section. As shown in FIG. 1(b), the developer thin layer forming blade 110 includes a thin plate spring 1 made of, for example, stainless steel, beryllium copper, or phosphor bronze plate.
10a, an elastic layer 110d formed on this tip and made of a rubber elastic material or resin having a JIS-A hardness of 30 to 85 degrees, such as silicone rubber or urethane rubber, and a conductive layer 110d having a chargeability opposite to that of the developer. The chip 110b is formed by laminating layers 110e.

As shown in FIG. 1(a), this chip 110b is bonded to one end along the elongated direction on one surface of the above-mentioned thin plate spring 110a having bidirectional surfaces. A sealing material 110C made of urethane foam is attached from one surface to the other of the flat spring 110a so as to seal both ends of the chip 110b. Note that the chip 110b can be attached using methods such as adhesion, fitting, or clamping, and any method may be used as long as it can be attached accurately. A phosphor bronze plate preferably having a thickness of 0.2 mm can be used as the thin plate spring 110a. Further, the thickness of the thin plate spring 110a is 0.1 to 0.1 depending on the shape.
It is possible to use one with a diameter of about 2 mm.

The chip 110b is composed of two layers: an elastic layer 110d and a charged layer 110e provided on the surface thereof. The charging layer 110e preferably has a charging property opposite to that of the developer. In this embodiment, the developer is negatively charged, and the charged layer 11
Reversal development is performed by positively charging Oe. The chip 110b is selected to have a certain degree of elasticity so as not to damage the surface layer of the developing roller. Therefore, in this embodiment, as the elastic body 110d of the chip 110b,
Charging layer 1 is made of urethane rubber of JIS-A standard 80".
As the material 10e, a conductive polyurethane paint having good adhesion to the elastic body 110d is used. This conductive polyurethane paint was created by selecting several types of suitable conductive polyurethane paints, and measuring their chargeability and abrasion resistance as follows.
The selection was made taking into consideration the results.

First, the chargeability of the conductive polyurethane paint was measured using an electrostatic coating surface analyzer shown in FIG. This device consists of a substrate on which a coating film 16 of conductive polyurethane paint is formed and inclined at an angle of 60" with respect to the horizontal plane, and a contact powder supply provided on the substrate and containing contact powder 17 for measurement. A member 15, a contact rice collection container 18 for collecting the contact powder 17 supplied onto the coating film 16, a fixing base 19 for fixing the collection container 18, and external terminals 21 led out from the substrate and the collection container 18, respectively. and an electrometer 20 having an external terminal 22 connected to it.
The contact powder 17 is poured onto the coating film 16, and the amount of electric charge generated due to friction is displayed on the electrometer 20. The measurement conditions are as follows.

Temperature: 25°C Humidity: 55% Contact powder: FL2030 (manufactured by Powder Chick) Amount of flowing material: 1.3 g Length of flowing material: Four types of conductive polyurethane paints A-D were tested using a device with a length of 90 or more. We conducted an evaluation. Furthermore, polyurethane paint A
For example, Subalex DH202313 (manufactured by Nippon Miractron ■), and for D, Electropack Z279 (
(manufactured by Taitai Manufacturing Co., Ltd.) was used. B1 and C are obtained by adding a charge control agent to polyurethane paint A to improve chargeability ('B and C have different types of control agents).

The results thus obtained are shown in Table 1.

Table 1 From the results, it was found that the conductive polyurethane paint D showed the highest amount of charge.

It was decided to use this conductive polyurethane paint for the charging layer of the chip 110b. The conductive polyurethane paint in D is manufactured by Taitai Kako and has the product name “Electropack 2279”.
It is. This "Electropack Z279" is a solution type paint, and was applied to the elastic layer 110d made of urethane rubber of the chip 110b by the method described below.

First, an equal amount of a diluting solvent prepared by mixing dimethylformamide (DMF) and methyl ethyl ketone (MEK) at a ratio of 1:1 was added to the stock solution of Electrovac Z279. After sufficiently stirring this diluted paint, the elastic layer 110d made of urethane rubber of the chip 110b is washed with a solvent.
The coating was carried out using a spray method. After coating, it was dried in air for about 2 hours, and then heat treated at 100° C. for 20 minutes. As a result, a charged layer 110e having a layer thickness of 30 μm was obtained. The thickness of the charged layer 110e can be varied from 10μIQ to 10μIQ by changing the spray irradiation time and the viscosity of the paint.
A range of up to 300μ■ is possible.

Next, as shown in FIG. 1(a), a chip 110b was adhered to a thin plate spring 110a, and a sealing material 110C made of urethane foam was attached to obtain a developer thin layer forming blade 110. In addition, sealing material 110C
was thicker than the chip 110b. Thereby, when the chip 110b is pressed against the developing roller, movement of the developer toward both ends can be reliably sealed. In this way, the sealing material 110C is attached to the developer thin layer forming blade 11.
Since it is arranged so as to wrap around the tip of the 0, it is possible to prevent peeling due to the conveyance of the developer and to realize a stable seal with a long life.

Further, since the developer thin layer forming blade 110 of the present invention has the chip 110b mounted on the thin plate spring 110a, it is possible to easily and reliably form an even developer layer by the elasticity of the thin plate spring 110b. is possible. However, the accuracy in the tangential direction between the developing roller and the chip 110b is important because it causes pressure unevenness, which affects the developer layer and the image.

Therefore, in the developer thin layer forming blade 110 of the present invention, the tip 110bl is attached to the thin plate spring 1 as shown in FIG.
It is mounted from a position spaced apart by dl from the tip of 10a. This spacing is used as a hold down and for positioning when mounting by molding or gluing. By sufficiently performing this holding and positioning, it is possible to improve the mounting structure of the thin plate spring in the lateral direction and the accuracy in the tangential direction with respect to the aforementioned developing roller. Note that if dl is too large, the pressure caused by the flow of the developer will cause poor layer formation, so it should be 0.5 n+m ~
5 m+s, preferably about 0.5 mm to 2 mm. In this embodiment, dl is set to 0.51. Further, the length L in the longitudinal direction of the tip 110b is the thin plate spring 110.
The length L in the longitudinal direction of a is shorter than c by d3. In other words, Ri. -L +
d + d, and the sealing member 110C made of the urethane foam described above is attached to the d2 and 63 portions. Considering the seal width, the length of d2+d3 should be about 6 to 30 mm, preferably about 6 to 20 mm, since a minimum of about 3 ohm on one side is required. Further, the length of the chip 110b at this time is set to be larger than the effective developing width, and the length of the thin plate spring 110C is set to be long enough to cover the sand seal of the developing roller.

A case where the developer thin layer forming blade 110 as described above is actually applied to a developing device will be illustrated.

FIG. 5 is a sectional view of the contact-type component nonmagnetic developing device 103. The developing device in this embodiment performs development by forming a thin layer of non-magnetic developer on the surface of a developing roller 109 having conductivity and elasticity, and bringing this into contact with the surface of the photoreceptor 102. . This device does not require a carrier, Mg roller, developer concentration control, etc., and can be made smaller and lower in price. The developing process will be explained below.

As shown in FIG. 4, the non-magnetic developer 113 in the developer container 112 is sent to the developer supply roller 111 while being stirred by the mixer 114, and is supplied to the development roller 109 by the developer supply roller 111. . This developer 113
As the developing roller 109 rotates, a part of the toner is adhered and conveyed by the mechanical conveying force of the developing roller 109 and the electrostatic force caused by charging caused by friction between the developing roller surface and other members. Thereafter, the developer transport amount is regulated by the blade 110 held by the blade holder A 117, the spacer 118, and the blade holder B 119 and brought into contact with the developing roller 109, and at the same time, the developer is triboelectrically charged due to friction therebetween. This apparatus uses a negatively charged organic photoreceptor drum 102 to perform reversal development. Therefore, a negatively charged developer is used as the developer, and the blade 110 is also made of a material that easily imparts a negative charge.

FIG. 7 is a perspective sectional view of the developing roller 109. The developing roller 109 is connected to a metal shaft 10 as shown in FIG.
9a, an elastic layer 109b formed on the metal shaft 109a, and a conductive layer 109 provided on this elastic layer.
It consists of C.

The developing bias potential is -200V with respect to the photoreceptor surface potential of -500V, which is applied to the developing roller 109 through a protective resistor.
Power is supplied to the metal shaft (109a) of the developing roller 1.
09 is about 1 to 4 m away from the photoconductor 102 in the direction of the arrow at a speed of about 1.2 to 4 times the photoconductor drum 102.
It rotates in contact with a contact width (developing nip) of about m. Since the developer particles are also charged at the development position, extremely sharp images with little fogging can be obtained. Recovery blade (Mylar film) 115 for residual developer
The scraped material returns to the developing device. Furthermore, if the developer falls from the developing roller 109 for some reason, it will stain the inside of the machine or the transfer paper, so a member 116 such as a plasticizer that reacts with the developer and fuses the developer is attached at the bottom. The above problems are overcome and the developing device 10 is
3 has the advantage that the developer will not fall even if it is placed upside down. In addition, in Figure 4, 12
Reference numeral 1 denotes a buckle plate attached to the blade holder A, which can seal the developer and suppress vibrations of the blade 110 by coming into contact with a foam material 123 made of maltblen or the like attached to the back side of the blade 110. A good developer layer can be formed on the developing roller 109.

Further, the blade 110 is connected to the rotating shaft 1 of the blade holder 117.
17a and a plurality of compression springs 120 for applying pressure to the developing roller 109.

Since the compression spring 120 has a spring constant lower than that of the thin plate spring material of the blade 110, it is possible to maintain a good developer layer.

Further, the blade 110 is connected to the rotating shaft 1 of the blade holder 117.
17a and a plurality of compression springs 120 for applying pressure to the developing roller 109.

Since the compression spring 120 has a spring constant lower than that of the thin plate spring material of the blade 110, it is possible to maintain a good toner layer.

In the developing device of the present invention, the developing roller 109 is required to have conductivity and elasticity. The simplest configuration that satisfies this is a combination of a metal shaft and a conductive rubber roller, but in order to obtain a sufficient contact width with the photoreceptor drum, the rubber hardness is preferably 50° or less according to the JIS standard, and the developer The surface needs to be smooth because it is conveyed while being pressed against the surface of the developing roller. Therefore, as shown in FIG. 6, in the developing roller used in the present invention, an elastic layer 1 is provided around the metal shaft 109a.
09b and a surface conductive layer 109c.

When selecting the elastic layer 109b of such a developing roller, there are two options: one that is conductive and one that is not.However, considering the possibility that the conductive layer 109c may be peeled off or scratched, the elastic layer 109b should also be selected. It is preferable that it be electrically conductive. Further, the elastic layer 109b
10 and the photoreceptor 102, permanent distortion (%) shown in JIS standard 6301 due to packaging or being left for a long time becomes a problem, and if it exceeds 10%, uneven development roller cycles may occur on the image Therefore, the compressive strain (%) of the elastic layer 109b is 10% or less, preferably 5%.
% or less is good. There is generally a relationship between the rubber hardness and permanent set (%) such that the larger the rubber hardness, the smaller the permanent set, so the balance between the materials and each other is important. As described above, conductive urethane rubber was selected in this embodiment as a material having the characteristics required for the elastic layer 109b, but it is also possible to use other conductive EPDM rubber, conductive silicone rubber, etc.

The elastic layer 109b made of conductive urethane rubber used in the present invention has a hardness of 3.
It had a hardness of 0° and an outer diameter of 18-. The electrical resistance value of the conductive urethane rubber is determined by placing the above elastic roller in parallel with a stainless steel roller with a diameter of 60+ am so that the contact width is about 2,
The result calculated by measuring the current observed when a potential difference of V was provided was 3.4×10 3 Ω·ω.

Moreover, the permanent set was measured using the measuring method shown in J I 5K6301 and was 3.0%.

Further, since the conductive layer 109C of the developing roller directly contacts the developer and the photoreceptor, a material is selected that will not contaminate the developer or the photoreceptor by seeping out plasticizer, vulcanizing agent, process oil, etc. The surface smoothness of the conductive layer 109C is 3.
A value of less than μlllR2 is desirable, and if it is more than that, an uneven pattern on the surface tends to appear in the image. Smoothness 3μtn
In order to realize Rz, a method can be considered in which a sufficiently thick conductive layer 109c is attached to the elastic layer 109b and then finished to a predetermined outer diameter and surface roughness by post-processing (polishing).
Since this method increases the cost, it is better to form the conductive layer 109C without post-processing. The elastic layer 109b
The surface roughness of the conductive layer 109C, the thickness of the conductive layer 109C, and the conductive layer 109
The viscosity of the paint used to form C must be optimally selected. FIG. 7a to FIG. 7C show the elastic layer 109.
109C is a diagram illustrating a typical method for forming a conductive layer 109C on FIG. FIG. 7A shows a spraying method, FIG. 7 shows a dipping method, and FIG. 7C shows a knife application method. The viscosity of the paint in each method is as follows: spray method, dipping method ≦ Knifetsu method, and when the paint film thickness is T (μm) and the surface roughness of the elastic layer 109b is S (μm Rz), in the spray method, T≧l0XS.

T≧5 in dipping method and Naifetsu method
If xS is satisfied, it becomes possible to make the surface smoothness of the conductive layer 3 μm Rz.

The conductive layer 109b is made of a polyurethane resin that has conductivity of 10 Ω by dispersing conductive carbon particles therein.

As such a polyurethane resin, conductive polyurethane rubber A (trade name "Subarex DH202313" manufactured by Nippon Miractron Co., Ltd.), which had the best abrasion resistance results shown in Table 1, was adopted. The conductive polyurethane paint A was applied to the surface of the elastic layer 109b made of conductive urethane rubber in the following steps, and after drying, heat treatment was performed to form the conductive layer 109b. "Subarex DH202313" is a solution type conductive polyurethane paint based on thermoplastic polyurethane.

First, methyl ethyl ketone (MEK) and tetrahydrofuran (THF) were added to the conductive polyurethane paint stock solution A.
Add an equal amount of a diluting solvent mixed in a 1:1 ratio. In this diluted solvent, as an acrylic resin charge control agent, an acrylic resin charge control agent manufactured by DuPont Co., Ltd., trade name "PC-100" was added at a ratio of 3% to 1 part of Sparex DH202313 stock solution. has been done. The paint of A is
As shown in the charge amount measurement results in Table 1, since the developer is charged in the same polar direction as the developer, this charge control agent is added to charge it in the opposite polarity. Addition of 3% charge control agent made it possible to obtain a charge amount of +603 nC, which is close to that of paint D.

Next, after thoroughly stirring this diluted paint, it was applied onto the surface of the elastic layer 106b, which had been washed with a solvent, using a dipping method. The pulling speed of the elastic layer 109b was 2.5 mm+/sec.

After application, dry in the air for about 30 minutes, then heat at 100°C.
Heat treatment was performed for 20 minutes. As a result, the layer thickness is 70-80
A conductive layer 109c of μl was obtained.

The layer thickness of the conductive layer 109c can be adjusted to 10 μL by changing the pulling speed of the dipping method and the viscosity of the paint.
It can be adjusted within a range of 1 to 500 μm. Through the above process, the resistance value between the metal shaft 109a and the conductive layer 109c is 5 x 103Ω.The hardness of the button and rubber is 63 according to the JIS standard.
01 type A hardness needle, 38°, surface roughness 3μta Rz
A developing roller 109 was obtained.

Next, a so-called laser printer is used, which forms a latent image by irradiating an organic photoreceptor with a negatively charged surface with a laser beam, and converts this into a visible image using a reversal development method.
An example in which the contact-type component nonmagnetic developing device 103 is applied will be described.

The image area potential, that is, the exposed area potential is -80V, the non-image area potential, that is, the unexposed area potential is -500V, the developing bias is -200V, the photoreceptor drum 102 and the developing roller 109.
When reversal development was performed with the contact width set to 1.5 mm and the circumferential speed ratio between the photoreceptor and the developing roller set to 1:2, an extremely sharp line image with an image density of 1.4 and no fogging was obtained. A printed sample with a solid image without unevenness was obtained. Furthermore, as a result of a life test of 10,000 sheets with this developing device, it was possible to obtain an extremely good image equivalent to the initial image even after the life test was completed.

FIG. 8 is a graph showing the relationship between the image density and the amount of charge of the developer from the initial stage up to 10,000 copies.

The image density was measured for a solid image, and the amount of charge of the developer was measured by using a charge amount measuring device 200 shown in FIG. 9(b) for 10 rotations of the roller. As shown in FIG. 9(a), this charge amount measuring device 200 includes a Faraday gauge 2 which is a conductive container having a suction pump 201 and an opening 203 provided opposite to a developing roller 109.
02, the developer on the developing roller 109 is suctioned and repaired by the Faraday gauge 202, and the average charge amount per unit weight of the developer is measured from the charge generated by electrostatic induction.

From this graph, it can be seen that when the above-mentioned developing device is used, the image density hardly changes even after 10,000 sheets are printed, and the amount of charge also hardly changes, making it possible to obtain a developing device with good image condition. Ta. This is chip 110
This is because the amount of wear of b is small, so that changes in the amount of developer entering and the width of contact with the developing roller 109 are very small and can be ignored.

For comparison, the chip 110 of the developer layer forming blade 110
A life test of 10,000 sheets was conducted by changing the material of b to silicone rubber with a rubber hardness of 80°, which is harder than the conductive layer 109 of the developing roller, and using a curved surface with a radius of 1.5 am, similar to the blade according to the present invention. In the initial images, we were able to obtain extremely good image samples equivalent to those of the present invention, but after 10,000 copies were completed, image density unevenness occurred at the leading and trailing ends of the inferior images, and the image density was uneven in the advancing direction. A streak appeared. This is because the tip 110b is worn out due to life.
The amount of developer that enters and the contact width with the developing roller 109 change greatly, the amount of charge of the developer changes, and the chip 11
This is because a scratch occurred on 0b.

FIG. 10 is a sectional view showing another embodiment of the developer thin layer forming blade used in the present invention.

This developer thin layer forming blade 212 is connected to the supporting member 211.
A urethane rubber plate 210a with a thickness of 3 mm is formed to have a curved surface with a radius of 1.5 mm on the surface that will come into contact with the developing roller, and a conductive polyurethane paint coated with the product name Electropack Z279 (Daibo Machining) is applied to the tip of this urethane rubber plate 210a. The conductive polyurethane 210b is coated with a conductive polyurethane 210b made by Co., Ltd.). This conductive polyurethane was formed using a diluted solvent and coating method similar to that of the previous embodiment. This developer thin layer forming blade 212 can be applied to the developing device shown in FIG. In such a developing device, the center of the curved tip of the developer thin layer forming blade 212 is pressed against the developing roller 109 with a predetermined pressure. In this embodiment, the pressing force is set by a plurality of springs, and the total pressing force of the springs is adjusted to be 1000 g. Note that the components of the developing device other than the blade 212 are the same as those in the previous embodiment.

A life test of 10,000 sheets was conducted using the above developer, and although the charge amount was slightly lower than that of the developer shown in the above-mentioned example, very good image samples were obtained both at the initial stage and at the end of 10,000 sheets. Obtained.

As described above, in one embodiment of the present invention, the developing roller 10
The developer thin layer forming blade 110 relative to 9 is again
st position, but the present invention is not limited thereto.
It may be in the ith position. Further, although the tip of the blade 110 has a curved surface, it may be a flat plate or a type that presses an edge.

Further, the developing method in this embodiment is a contact developing method using an elastic roller, but the developing roller may be made of metal or resin, and the toner may also be a magnetic toner developing method. In addition to the contact development described above, the present invention can be applied to known development methods such as jumping development in which development is performed by flying toner.

[Effects of the Invention] As explained above, according to the present invention, the developer is sufficiently charged, and stable high-quality images can be obtained without image defects such as image density unevenness or fogging or deterioration even after long-term use. It is possible to provide a developing device that can obtain an image of

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view showing an example of the developer thin layer forming blade of the present invention, and FIG. 1(b) is an A--
A sectional view, FIG. 2 is a diagram showing an example of the developer thin layer forming blade of the present invention and the state of contact with the developing roller used in the present invention, and FIG. 3 is an electrostatic coating film surface analysis device. FIG. 4 is a plan view showing the arrangement of a thin plate spring and a chip in an example of the developer thin layer forming blade of the present invention. FIG. 5 is a schematic diagram of the developing device used in the present invention. The figure is a partially cutaway sectional view showing an example of the developing roller used in the present invention, and FIGS. 7(a) to 7(c) show various methods for forming a conductive layer on the elastic layer of the developing roller. A schematic diagram showing
FIG. 8 is a graph showing changes in image density and toner charge amount of the developing device according to the present invention, FIG. 9(a) is a schematic diagram showing a method for measuring the charge amount of developer on the developing roller, and FIG. figure(
b) is a perspective view of a charge amount measuring device used in the measuring method of FIG. 9(a), and FIG. 10 is a diagram showing another example of the developer layer forming blade of the present invention. 109...Developing roller, 109a...Metal shaft, 109b...Elastic body layer, 109C...Conductive layer, 1
10...Blade, 110a...Thin plate spring material, 11
0b...Chip, 110C...Sealing material, 110d
...Elastic body layer, 110e... Engraving of charged layer drawing (no change in content) 10b (b) Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 (b) Fig. 7 Fig. 8 (a) (b) Figure 9 Figure 10 Procedural correction blind motion) % formula % 1. Indication of the case Patent application No. 2-340537 (307) Toshiba Corporation (and 1 other person) 4. Agent Tokyo 3-7-2-6 Kasumigaseki, Chiyoda-ku, drawing 7 subject to amendment, content of amendment As per the engraving and attachment of drawing No. 1 originally attached to the application (no change in content)

Claims (1)

[Claims] A developing device that visualizes a latent image by bringing a thin layer of developer formed on a developing roller close to or in contact with an image carrier disposed opposite to the developing roller, the developing device comprising: a supporting member; and the supporting member. 1. A developing device comprising: a developer thin layer forming means having a laminate formed on top of the developing roller and having a charged layer and an elastic layer laminated from the side facing the developing roller.