JPH0962097A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stable development for a long period by constituting a developer control member of an elastic base having elasticity and a glass layer formed on the elastic base surface. SOLUTION: The developer control member is constituted of an elastic blade 22 being the elastic base having the elasticity, and the glass layer 23 disposed on the surface of a free end part and peripheral part of the elastic blade 22. The glass layer 23 is composed of a porous material. The thin layer of the developer 16 is formed on the developing roller 18 by the porous glass layer 23. Moreover, the porous glass layer 23 on the elastic blade 22 surface is the material allowed to positively attain toriboelectrification with the toner being the developer 16, and particularly effective with respect to the negative toner. Then, the elastic blade 22 regarded as the base body of the porous glass layer 23 is composed of the conductive material, therefore the charge of the excessively electrified toner is allowed to pass through the porous glass layer 23, and electrically neutralized by the conductive elastic blade 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus used for developing an electrostatic latent image formed on an image carrier in an electrophotographic apparatus or the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic apparatus, an electrostatic latent image formed on an image carrier is developed by a developing device and visualized as a toner image.

As a developing method in such a developing device,
A non-magnetic toner is used as a one-component developer, the toner is applied trivially on the developing roller while being triboelectrically charged, and then the toner is brought into contact with the electrostatic latent image on the developer under voltage application There is a method of developing so as to face each other.

Further, as a technique for forming a thin layer of a developer in a developing device, a developer regulating member which is in pressure contact with a developer carrier as described in Japanese Patent Publication No. 63-15580 is made of metal. There is one that integrally has a thin plate material having a spring property and a soft elastic body located between the thin plate material and the developer carrying member.

[0005]

However, in the above-mentioned technique, the developing device is used because the portion that is in pressure contact with the developer carrying member via the developer is the soft elastic body of the developer regulating member. As a result, the soft elastic body rubs against the developer, and the soft elastic body is worn. As a result, the worn portion of the soft elastic body causes unevenness in the thin layer of the developer, which adversely affects development and leads to deterioration in image quality.

In order to prevent the image quality from being adversely affected, the developer regulating member or the developing device including the developer regulating member must be quickly replaced due to the consumption of the soft elastic body.

Therefore, a main object of the present invention is to provide an image forming apparatus capable of keeping an excellent image for a long period of time.

[0008]

According to a first aspect of the present invention, there is provided an image having a developer carrying member carrying a developer, and a developer regulating member forming a developer layer on the developer carrying member. In the forming apparatus, the developer regulating member is composed of an elastic base having elasticity and a glass layer formed on the surface of the elastic base, which is an image forming apparatus.

Therefore, since the developer regulating member is composed of the elastic base having elasticity and the glass layer formed on the surface of the elastic base, the hardness of the contact portion with the developer becomes large.

According to a second aspect of the present invention, in an image forming apparatus having a developer carrying member carrying a developer and a developer regulating member forming a developer layer on the developer carrying member, In the image forming apparatus, the developer regulating member includes an elastic base having elasticity and a porous glass layer formed on the surface of the elastic base.

Therefore, since the developer regulating member is composed of the elastic base having elasticity and the porous glass layer formed on the surface of the elastic base, the surface area of the contact portion with the developer is large and the hardness is also large. Become.

According to a third aspect of the present invention, in an image forming apparatus having a developer carrying member carrying a developer, and a developer regulating member forming a developer layer on the developer carrying member, The image forming apparatus is characterized in that the developer regulating member is composed of a conductive elastic substrate that is conductive and has elasticity, and a porous glass layer formed on the surface of the conductive elastic substrate.

Therefore, since the developer regulating member is composed of the conductive elastic substrate which is conductive and has elasticity, and the porous glass layer formed on the surface of the conductive elastic substrate, the overcharged development is carried out. The charge of the agent is neutralized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The image forming apparatus 10 of this embodiment shown in FIG. 1 is used, for example, in a laser printer using a reversal developing method. However, the present invention can be used in any image forming apparatus of the same kind other than such a laser beam printer, such as a copying machine or a facsimile.

The image forming apparatus 10 includes a photosensitive drum 12 for electrophotography. The photosensitive drum 12 has a negative potential Vd (for example, Vd = -70) due to a primary charger (not shown).
After being uniformly charged to 0 V), it is exposed by an exposing unit (not shown) such as a laser beam, and a negative electrostatic latent image having a potential Vl = -100 V is formed on the photosensitive drum 1.
2 is formed.

The image forming apparatus 10 also includes a developing device 13 including, for example, a removable developing cartridge. The developing device 13 is, for example, a developing container 1 made of resin or the like.
Including 4. The developer 16 is contained in the developing container 14. A one-component toner is used as the developer 16, and a non-magnetic one-component toner is particularly suitable in this embodiment. Recycled toner may also be used as the developer 16. The average particle size of the developer 16 is, for example, about 10 μm. When, for example, a negative polarity developer is used as the developer 16, the development is reversal development. Then, the developer 16 in the developer container 14 is applied to the developing roller 18 made of a semi-conductive elastic body by the supply roller 20, and the developing roller 18 is made to carry the developer 16.

It should be noted that the developer regulating member is
This is that it is composed of an elastic blade 22 which is an elastic base having elasticity, and a glass layer 23 provided on the surface of the free end of the elastic blade 22 and its periphery. The glass layer 23 is porous. The porous glass layer 23 forms a thin layer of the developer 16 on the developing roller 18.

The developer layer has a two-layer structure of developer 16, for example. Therefore, in this case, assuming that the average particle diameter of the developer 16 is about 10 μm, the layer thickness of the developer layer is about 20 μm.
(= 10 μm × 2).

After that, the developer 16 on the developing roller 18 is brought to the photosensitive drum 12 by the rotation of the developing roller 18. The photosensitive drum 12 and the developing roller 18 are in contact with each other at a predetermined pressure. Then, the photosensitive drum 1
The electrostatic latent image on 2 is developed and visualized. As the material of the elastic blade 22, for example, an insulating material having a polar property different from that of the developer 16 is used in order to positively charge the developer 16 by friction, and when the developer 16 has a negative polarity, for example, Quartz powder-filled silicon, polyamide 66, or the like is used. The other end side of the elastic blade 22 is supported by a blade support portion 24 formed integrally with the developing container 14.

The bias power source 26 applies a developing bias to the developing sleeve of the developing roller 18, for example, V.
A DC voltage of _B = -300V is applied, and further, for example, V _S0 = -4 from the bias power source 28 to the supply roller 20.
A DC voltage of 00V is applied. When the potential difference between V _B and V _S0 is set to about 100 V in this way, the transfer ability of the developer 16 from the supply roller 20 to the developing roller 18 can be maximized, and the developer 16 can be easily transferred to the developing roller 18. You can When the developer 16 has a positive polarity, the positive and negative signs of V _B and V _S0 are opposite.

Next, the arrangement of the developing roller 18 and the supply roller 20 will be described with reference to FIG. The distance m between the developing roller 18 and the supply roller 20 is set to a layer thickness n of the developer layer or more. Specifically, when the separation distance m is 0.02 mm or more, even when recycled toner is used as the developer 16, there is no clogging such as toner aggregation or cotton dust, and there are no streaks or uneven density images. Can be obtained. On the other hand, when the separation distance m is 2 mm or less, the developer 16 on the supply roller 20 can be sufficiently rubbed against the surface of the developing roller 18, and the density of the developer 16 does not decrease. In other words, when the separation distance m exceeds 2 mm, the bias voltage is applied to the supply roller 20 to apply the developer 1 to the developer 1.
Even if the transfer capacity of 6 is maximized, the developer 1 is transferred to the developing roller 18.
6 cannot be supplied sufficiently.

Therefore, the separation distance m and the layer thickness n of the developer layer should satisfy the conditions of m ≧ n and 0.02 mm ≦ m ≦ 2 mm.

Next, the thickness t of the elastic blade 22 is 0.1.
mm to 0.3 mm is preferable, and the thickness s of the porous glass layer 23 is preferably 1 μm to 10 μm.

The porous glass layer 2 on the surface of the elastic blade 22
3 is a material that positively performs triboelectric charging with the toner as the developer 16, and is particularly effective for minus toner. Further, the elastic blade 22 that is the base of the porous glass layer 23 is made of a conductive material, and the charge of the overcharged toner passes through the porous glass layer 23 and is electrically converted by the conductive elastic blade 22. Since such neutralization is performed, a substantially uniform charge can be obtained, and an image without streaks and uneven density due to development can be formed.

Since the contact portion between the developer 16 and the developer regulating member is hard because it is the porous glass layer 23, the porous glass layer 23 is not scraped even in the overprinted area and the porous glass layer 23 is not generated. Deformation such as unevenness due to changes with time does not occur. Therefore, the durability of the developer regulating member can be improved.

Here, a manufacturing method for forming the porous glass layer 23 on the elastic blade 22 will be described.

First, using the elastic blade 22 as a substrate, a solution prepared by adding ammonia water to silicon alkoxide is coated on the surface by a dip coating method, and this is dried at 120 ° C. to have the above-mentioned thickness s. A porous glass layer 23 having a thickness of 1 μm to 10 μm is formed.
At this time, the glass layer becomes a silica layer.

This step is one of the thin film forming methods called the sol-gel method. Here, silicon ethoxide and silicon etramexide are the main components, and a medium such as HCl or NH ₃ and water are suitable. A silica layer is formed by applying and drying the added solution.

According to this method, dozens of Å are contained in the silica layer.
Therefore, very small pores of about several hundred Å can be formed to form a porous silica layer. The porosity is about 50%.

The porous silica layer basically has an insulating property, but by filling the pores with another substance, it becomes possible to control the physical properties. For example, the pores are electrically conductive. By charging with a substance having a volatile property, it is possible to further neutralize the overcharge of the developer 16, which greatly contributes to the uniform charge of the developer 16.

By doing so, it was confirmed that there was little variation in image density and there was a sufficient effect of satisfying the life of the developer regulating member.

Now, the separation distance m is 0.02 mm ≦ m ≦ 2 mm
The condition is obtained from the experimental result shown in FIG.

FIG. 3 is a graph showing subjective evaluation of image quality for each separation distance m when the separation distance m is changed. Line A is when the number of prints is initial, and line B is when the number of prints is 7,000. Here, the subjective evaluation of image quality is a comprehensive evaluation of image quality factors such as image density after development, fogging, streaks, density unevenness (density difference in one sheet of recording paper), and fine lineability (whether fine lines are clearly visible). It is a 10-level evaluation. Then, if the subjective evaluation of image quality is 7 or more, it is determined that the image quality is good. Then, as is apparent from FIG. 3, if the separation distance m is in the range of 0.02 mm to 2 mm, the image quality is in a good range, and the condition of 0.02 mm ≦ m ≦ 2 mm is derived. In this way, when the separation distance m is set in the range of 0.02 mm to 2 mm, the life of the developing device 13 is exceeded.
Even after printing 000 sheets, a good image is formed without causing the density decrease due to the deterioration of the roller and the occurrence of streaks and density unevenness due to clogging of dust.

Further, the axial length of the supply roller 18 is made larger than the width of the recording paper (length in the direction orthogonal to the traveling direction of the recording paper), and the separation distance m is 0.02 mm≤m≤2.
By setting to satisfy the condition of mm, the developing roller 1
The developer 16 can be sufficiently supplied to the developing roller 8, and the developer layer can be uniformly formed on the developing roller 18 in a range wider than the width of the recording paper. Therefore, the image density on the recording paper does not decrease, and an image without density unevenness can be obtained. Further, since the developer 16 can be sufficiently supplied, a good image can be obtained even when a black solid image is continuously printed, and the black solid followability is improved.

As the supply roller 20, a hard roller made of a material such that the separation distance m does not change, such as metal or hard plastic, is used. This is because, when the developing roller 18 and the supply roller 20 are separated from each other, if the supply roller 20 is formed of a foam member such as sponge, the separation distance m changes due to deformation of the sponge and the separation distance m is 0.02 mm ≦. This is because if the condition of m ≦ 2 mm is not satisfied, an adverse effect such as low image density will occur. As the metal used for the hard roller, there are (1) austenitic SUS material, and (2) sulfur composite free-cutting steel / steel SUM material with surface treatment such as electroless nickel plating. Used for the hard roller. As hard plastic, polyamide nylon 66, MC
Nylon, acetal resin-based polyacetal, etc. having hardness of JISA 80 degrees or more.

The separation distance m is 0.02 mm to 0.
If it is 3 mm, a more preferable effect can be obtained. In this case, even if the bias voltage is not applied to the supply roller 20,
Only the rotation (mechanical force) of the supply roller 20 causes the developer 16
Can be supplied to the developing roller 18. That is, when the supply roller 20 is made of a conductive material such as metal, the supply roller 2 must be applied unless a bias voltage is applied to the supply roller 20.
The surface potential of 0 is about -200V. Therefore,
When the developing bias is −300 V as described above, when the developer 16 has a negative polarity, the developing roller 18 is included in the developer 16.
The force of moving from the direction toward the supply roller 20 acts. Nevertheless, if the separation distance m is limited to 0.02 mm to 0.3 mm, the developer 16 can be supplied from the supply roller 20 to the developing roller 18 only by rotating the supply roller 20. Furthermore, since it is not necessary to apply a bias voltage to the supply roller 20, the supply roller 20 may be made of a material other than a conductive material, and in this case, the supply roller 20 also applies the developer 16 to the developing roller 18. Can be fully supplied.

Therefore, by constructing the image forming apparatus 10 as described above, an image without density unevenness can be obtained.

Further, like the image forming apparatus 10 'shown in FIG. 4, the elastic blade 22' may be integrally formed with the blade supporting portion 24, that is, the developing container 14 by integral molding. Other configurations are similar to those of the embodiment shown in FIG. Therefore, the elastic blade 22 ′ is formed of, for example, resin, like the developing container 14.

In this way, by forming the elastic blade 22 'of resin, for example, a blade having insulating properties and appropriate elasticity can be obtained, and a thin layer of the developer 16 can be uniformly formed on the developing roller 18. Also, the elastic blade 2
Since 2'is integrally formed with the developing container 14, it is possible to omit the work required for mounting. Therefore, conventionally, when attaching the elastic blade to the developing container,
The angle and pressure with respect to the developing roller had to be finely adjusted, which led to inefficiency during assembly and high cost, but such an adverse effect can be eliminated.

In each of the above embodiments, the developer 1
Even if a recycled toner is used as No. 6, a good image can be obtained. Further, the average particle size of the developer 16 is not limited to 10 μm, and the developer 16 having an arbitrary average particle size such as a small particle size of 6 μm and a large particle size of 15 μm can be used.

[0041]

In the invention according to claim 1, since the developer regulating member is composed of the elastic base having elasticity and the glass layer formed on the surface of the elastic base, the hardness of the contact portion with the developer is large. Become. Therefore, the surface of the glass layer, which is in contact with the developer, cannot be uneven due to the friction caused by the developer, so that stable development can be supplied for a long period of time, and as a result, a device with stable image quality can be provided. . Further, it is possible to extend the replacement time of the developer regulating member or the developing device including the developer regulating member.

In the invention according to claim 2, since the developer regulating member is composed of the elastic base having elasticity and the porous glass layer formed on the surface of the elastic base, the effect of the above-mentioned claim 1 is obtained. In addition, since the surface area of the contact portion with the developer is increased, the triboelectrification efficiency of the developer can be improved. As a result, it is possible to provide a more stable apparatus with good image quality.

In the invention according to claim 3, the developer regulating member is composed of a conductive elastic substrate which is conductive and has elasticity, and a porous glass layer formed on the surface of the conductive elastic substrate. Therefore, the charge of the overcharged developer is neutralized, and uniform charge of the developer is obtained. As a result, it is possible to form an image without streaks and uneven density due to development.

[Brief description of drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention.

FIG. 2 is an enlarged view showing a peripheral portion of a developing roller.

FIG. 3 is a graph showing subjective evaluation of image quality with respect to a distance m.

FIG. 4 is an illustrative view showing another embodiment of the present invention.

[Explanation of symbols]

 10, 10 '... Image forming apparatus 12 ... Photosensitive drum 13 ... Developing device 14 ... Developing container 16 ... Toner 18 ... Developing roller 20 ... Supplying roller 22, 22' ... Elastic blade 23 ... Porous glass layer 24 ... Blade supporting portion 26, 28 ... Bias power supply

Claims (3)

[Claims] 1. An image forming apparatus comprising: a developer carrying member carrying a developer; and a developer regulating member forming a developer layer on the developer carrying member, wherein the developer regulating member has elasticity. An image forming apparatus comprising an elastic base member and a glass layer formed on the surface of the elastic base member. 2. An image forming apparatus having a developer carrying member carrying a developer and a developer regulating member forming a developer layer on the developer carrying member, wherein the developer regulating member has elasticity. An image forming apparatus comprising an elastic base member and a porous glass layer formed on the surface of the elastic base member. 3. An image forming apparatus comprising: a developer carrying member carrying a developer; and a developer regulating member forming a developer layer on the developer carrying member, wherein the developer regulating member is conductive. An image forming apparatus comprising: a conductive elastic substrate having elasticity and a porous glass layer formed on the surface of the conductive elastic substrate.