JPH041781A - Image forming device - Google Patents

Abstract

PURPOSE:To prolong the life of the respective parts of the image forming device and to reduce the cost thereof by forming a diamong-like film in at least the part of an elastic blade in contact with an image carrying member. CONSTITUTION:One edge of a cleaning blade 3 formed with the diamond-like film 6 on the front surface is pressed to the aperture part on the image carrying member side of a cleaning device 2. The residual toners remaining on the surface of the image carrying member without making contribution to transfer are scraped by the cleaning blade when these toners arrives at the edge part. The toners recovered in such a manner are housed into a toner storage part 4. Namely, the friction between these means and the image carrying member as well as a developing sleeve is drastically decreased and the generation of blade peeling is surely prevented, by which the workability is enhanced, the wear resistance is improved and the denaturation in high-temp. and high- humidity environment is prevented. Good-quality images are obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus using an electrostatic transfer process, such as an electrostatic copying machine and a printer thereof.

(Prior art and problems to be solved) After charging the surface of an image carrier, forming an electrostatic latent image on the charged surface and applying toner to this latent image to form a toner image,
Furthermore, in a well-known image forming apparatus configured to transfer this toner image onto a transfer material such as paper, a blade made of an elastic material is brought into pressure contact with an image carrier, etc. in order to perform the above-mentioned series of operations. This method is being implemented in the appropriate places.

Such an embodiment will be briefly described with reference to a known image forming apparatus shown in FIG.

An elastic charging blade 1 made of a conductive material is mounted on an image carrier 101 that extends perpendicularly to the plane of the paper and rotates in the six directions of arrows.
02 is brought into pressure contact to uniformly charge the surface of the image carrier 101, and an appropriate image exposure such as an image-modulated laser beam is performed on the charged surface to form an electrostatic latent image.

As the image carrier 1 rotates, the electrostatic latent image is transferred to the developing device 10.
3, the toner is supplied from the developing device 103 and visualized.Furthermore, when this visualized toner image reaches the transfer site where the transfer charger 104 is arranged, the timing is set. Also, as indicated by P in the figure, a transfer material is supplied to the transfer site, and a transfer bias is applied by the transfer charger 104, so that the toner image on the image carrier lot side is transferred to the transfer material.

Thereafter, the transfer material carrying the toner image is conveyed to a fixing site (not shown), and part of the toner that was not transferred to the transfer material during transfer is cleaned by a cleaner 105, and the image carrier 101 is transferred to the next step. Be able to enter.

In such an image forming apparatus, the illustrated apparatus includes a charging blade 102 and a developing device 103 as secondary charging means.
The blade 10 comes into contact with the developing sleeve 108 disposed in the
9 and a cleaning blade 111 as a cleaning means provided in the cleaner 105, and elastic blades are provided at three locations in the counter direction.

To briefly describe these blades, the charging blade 10
2, by applying an alternating voltage in which alternating current is superimposed on direct current, an air discharge is generated in the gap between the image carrier 101 and the charging blade 102, and the image carrier 10
1 surface is negatively charged.

This type of charging means is gradually being used because it has the advantages of not requiring a high-voltage power supply, generating less ozone, and being cost-effective compared to the well-known method using a corona discharger. It's starting to look like this.

On the surface of the developing sleeve 108 of the developing device 103, the charged toner stored inside the developing device 107 is formed by a blade 109 to form a --like thin toner layer.

The cleaning blade 111 scrapes off and collects some toner that has not been transferred to the transfer material at the transfer site.

Since each of the blades mentioned above is in pressure contact with the image carrier or the developing sleeve, it is necessary to use a material with high wear resistance, for example, urethane rubber is often used. In addition, as a method of arranging them, a counter method is generally used as shown in the figure.

However, when the blades arranged in this manner are subject to large friction with the image carrier, such as in the early stages of equipment use, so-called blade curling occurs and the blades no longer function as expected. condition may occur.

In order to avoid such blade damage, a lubricant such as polyvinylidene fluoride with a small particle size is dispersed in Freon and applied to the part where the blade contacts the image carrier, etc., and then the image is removed. It has been carried out to bring it into contact with a carrier or the like.

However, with this method, it took a long time to dry after application, resulting in poor workability (also, it was difficult to apply the product evenly over the entire length of the blade edge, resulting in unsatisfactory results). be.

In addition, as mentioned above, since each blade is in pressure contact with the image carrier or the developing sleeve, it is inevitable that it will be locally worn or damaged by repeated use.
This also poses the risk of non-uniform charging in the case of a charging blade, irregular formation of a toner layer in the case of a developing blade, and poor cleaning in the case of a cleaning blade.

Furthermore, when using urethane rubber as the material,
Due to long-term use, this material is hydrolyzed and denatured, so that it no longer exhibits its original physical properties, which may also lead to the above-mentioned disadvantages.

Describing the defects caused by these on a blade-by-blade basis, in the case of the charged blade 102, the blade (
If this happens and the tip of the blade comes into contact with the blade in the forward direction, it becomes difficult to generate a discharge with good convergence between the blade and the image carrier, and the blade is not uniformly charged. If local damage or deterioration occurs at the contact edge portion of the image bearing member, the contact state with the image carrier becomes unstable, resulting in charging failure.

Regarding the blade 109 that comes into contact with the developing sleeve, if the blade turns over, the wedge-shaped gap formed by this becomes clogged with toner, making it impossible to control the toner layer that should be formed on the sleeve, and also causing wear and tear. Even when denaturation and deterioration occur, the control effect of the toner layer by the blade deteriorates, making it impossible to form a uniform toner layer.

Furthermore, regarding the cleaning blade 111, the occurrence of blade curling, damage to the contact edge, deterioration and deterioration of the toner, etc. may reduce the toner removal function, resulting in poor cleaning, and furthermore, the toner may be fused to the image bearing member. This results in deterioration of image quality.

The present invention has been made in order to cope with such a situation, and is an image forming apparatus as described above, which is provided with an elastic blade in contact with an image carrier, etc., at at least one of the charged parts and other parts. In some cases, the blade is small (
A diamond-like coating is formed on the part that contacts the image carrier to prevent the occurrence of blade fraying, local damage, etc., improve workability, and obtain a blade that can withstand long-term use. The purpose is to extend the life of each part of an image forming apparatus and reduce costs.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention comprises a moving image carrier, a charging means disposed around the image carrier, and a developing sleeve. In an image forming apparatus equipped with a developing means and a cleaning means, at least one of the means includes a blade that comes into contact with the image carrier or the developing sleeve, and at least a portion of the blade that comes into contact with the image carrier etc. is coated with diamonds. This is an image forming apparatus characterized by forming a shaped film.

With this configuration, it is possible to reliably prevent the occurrence of blade curling, edge breakage, etc., thereby improving workability, and also making it possible to stably perform the desired function over a long period of time.

(Explanation of Examples) As mentioned above, the diamond-like coating formed on the surface of each blade is created using plasma that decomposes methane gas by glow discharge.
The film is formed by injection CVD method.
It is amorphous, an intermediate state between graphite and diamond, and an example of its manufacturing method is shown in Figure 1.

This figure is an explanatory diagram showing the configuration of the manufacturing apparatus. Methane gas or argon gas, which is a raw material, flows into a container 56 from an inlet 51. At this time, it is excited by an excitation coil 52, and then a power supply 53 near the inlet is excited. grid and
Ions are deposited and formed into a film on the surface of the blade 54 by applying a bias voltage between the aluminum substrate 55 on which the blade 54 is placed.

Excess gas is exhausted through outlet 57.

The film formed in this way has a high hardness of 3000 kg/2 on the Vickers scale and has excellent wear resistance, and by coating the blade surface with this film, it is effective in preventing deterioration of the blade material due to aging. . Furthermore, since the film is formed by vapor deposition, it is formed to have a uniform thickness, and since the raw material is methane gas, it is advantageous in terms of cost.

FIG. 2 shows an embodiment of a cleaning device equipped with a cleaning blade coated with a diamond-like film as described above, the cleaning blade having a cylindrical shape and having an axis perpendicular to the plane of the paper. A cleaning device 2 is disposed parallel to the image carrier 1 which is rotated in six directions indicated by arrows in the figure.

One edge of a cleaning blade 3 having a diamond-like coating 6 formed on the entire surface is in contact with the opening of the cleaning device 2 on the side of the image carrier. When the residual toner remaining on the body surface reaches the edge portion, it is scraped off by the cleaning blade, and the toner thus collected is stored in the toner storage section 4.

Note that the reference numeral 5 in the figure is a scoop sheet.

It goes without saying that members required for image formation, such as a charging means, an exposure means, a developing means, and a transfer means, are arranged around the image carrier, but these are not necessary for explaining the embodiments of the present invention. Parts that are not included are omitted, and the same applies to the following embodiments.

As mentioned above, one edge of the cleaning blade is in pressure contact with the image carrier, but the friction coefficient of the diamond-like coating formed on it is extremely small, less than 0.1, and the edge of the cleaning blade is in pressure contact with the image carrier. Since the lubricity between the carrier surfaces is significantly improved, it is possible to reliably prevent the occurrence of blade curling, and it is also possible to omit the process of applying lubricant to the edges at the initial stage of use. .

In addition, as the hardness of the diamond-like coating is high as mentioned above, it sufficiently prevents blade wear and local damage.
You can expect a long-term and stable cleaning effect.

Next, the results of a comparative experiment between a blade made of urethane rubber alone and a blade coated with a diamond coating will be briefly described.

Thickness 2nu++ supported on blade holder, free length 1
A plate-shaped blade with a rubber hardness of 0+a+n and a rubber hardness of 65°, and a blade on which a diamond-like coating with a thickness of 5 μm was formed were used.

These were brought into contact with an OPC photoreceptor having a diameter of 60 mm under the same conditions.

The contact conditions are as shown in Fig. 3, contact angle θ = 25°.
, penetration amount δ=0.8, the contact pressure at this time is 30 gr
/ cm.

In order to obtain a sufficient leaning effect, it is preferable that the contact angle θ is 18 to 32'', the penetration amount δ is 0.5 to 1.5 mm, and the contact pressure is 5 to 45 gr/cII+.

When paper was passed under these conditions, cleaning failures occurred after approximately 100,000 sheets of A4 size paper using a blade made solely of urethane rubber, and when the edges were observed under a microscope, numerous defects were found. It was seen.

On the other hand, a blade with a diamond-like coating formed with 2
Even after passing 00,000 sheets, it was confirmed that no cleaning defects occurred and there were no defects at the edges.

Furthermore, the blade formed with this film also acts as a protective film to maintain the properties of the blade body under high temperature conditions.

Regarding the experimental results regarding this, a blade made of urethane rubber similar to the one mentioned above and a blade with a diamond-like coating formed thereon were tested using an OPC with a diameter of 60 mm.
When the photoconductor was brought into pressure contact under the same conditions and left in an environment of 30°C and 80% RH for two years, the former was initially slightly transparent due to a hydrolysis reaction, but became cloudy and hardened, with almost no contact pressure. Ogr/cm and lost its cleaning function, but in the latter case, there was almost no change in appearance or characteristics;
It was confirmed that the leaning function was sufficiently preserved.

Note that the above-described effects are sufficient if the thickness of the diamond-like coating is 0.5 μm or more, and when productivity is taken into account, it is preferable to keep the film thickness to 10 μm or less.

FIG. 4 shows an embodiment in which a blade on which a diamond-like coating is formed is used as a charging blade, in which a charging device 8 is arranged close to an image carrier l rotating in the direction indicated by the arrow in the figure. A charging blade 8 attached to a support member 9 of the device is in contact with the counter in the counter direction, and a diamond-like coating 10 similar to that of the previous embodiment is formed on the surface of the blade.

Reference numeral 11 denotes a high-voltage power supply, which applies, for example, a dark potential V to the surface of the image carrier. When charging, ■. The surface of the image carrier is uniformly charged by applying a superimposed AC component having a peak-to-peak voltage that is twice or more the charging start voltage when a DC voltage is applied to the blade 8 on a corresponding DC component.

A belt like this! In the device, by forming a diamond-like film as described above on the surface of the charging blade 8, it is effective in preventing blade curling, edge breakage, and characteristic change due to long-term use, as in the case of the previous embodiment. In addition, the following effects can be expected.

That is, in the case of a charging means configured as shown in the figure, the image carrier 1
Discharge occurs in the gap between the surface and the charging blade 8 on the downstream side when viewed in the rotational direction of the image carrier, and as a result, even if it is a small amount, ozone is generated in this area, which cannot be avoided. Because the blade is exposed to an atmosphere of It prevents denaturation and maintains stable charging function over a long period of time.

Note that the resistance value of the charging blade is preferably about 10 7 to 10 11 Ω, and if the resistance value is high, the voltage applied to the image carrier will substantially decrease, so it is necessary to increase the applied voltage. If the resistance value of the blade is low, a high voltage is directly applied to the image carrier, which tends to cause leakage to the image carrier or the blade. However, the volume resistance of the diamond-like film mentioned above is lQ+2Ωcm.
In the case of the film thickness as mentioned above, the resistance value is about 108
~1010Ω, and after forming a film on the surface, the original (
There will be no inconvenience.

FIG. 5 shows still another embodiment of the present invention, in which the blade is pressed into contact with a developing sleeve disposed in a developing device.

In the figure, a developing device 12 is disposed close to an image carrier 1, a sleeve 15 is provided surrounding a magnet roller 16 disposed inside the developing device 12, and a diamond-like coating 20 is formed on the sleeve 15. It is assumed that the blade 18 is in contact with the counter direction, and a voltage obtained by superimposing alternating current and direct current is applied to the sleeve 15 by a power source 19.

In the case of a developing means in which the toner container 17 contains non-magnetic toner and magnetic particles as a coating member for adhering the toner to the sleeve, the blade 18 is placed on the surface of the sleeve 15 around the edge including the edges. The magnetic particles are restrained in the container by being brought into contact with each other in a state of -, and the toner that has acquired a predetermined charge due to frictional charging with the magnetic particles is attached to the sleeve surface to form a thin layer. As the toner rotates, it is brought to a development site where it and the image carrier face each other, and is attached to the electrostatic latent image formed on the image carrier to form a toner image.

In this case, since the blade 18 is formed with the highly hard diamond-like coating 20 as described above, there is a great effect as described below.

That is, the blade 18 is in pressure contact with the sleeve surface which has been roughened with alundum abrasive grains passing through a No. 400 mesh, and furthermore, a large amount of magnetic particles made of iron powder, ferrite powder, etc. are present in the container 17. As a result, with use, the blade edges and adjacent areas become extremely rough and worn, making it difficult to form a toner layer on the sleeve surface.

However, as mentioned above, the diamond-like coating formed on the surface of the blade 18 has extremely high hardness and high wear resistance, so it can withstand the above-mentioned adverse conditions and maintain stable function over a long period of time. This is promising and greatly contributes to obtaining high-quality images.

Although the case of a two-component developer has been described above, it goes without saying that basically the same effect can be obtained in the case of a one-component non-magnetic toner, a one-component magnetic toner made of ferrite powder, etc.

As the developing blade 18, its resistance value is 10'~
It is preferable to use one with a resistance of about 1011Ω.

If the resistance is low, the toner will flow between the blade 18 and the sleeve 15.
Excessive charge is injected into the toner when it passes through the toner, making it difficult to transfer to the latent image on the image bearing member, resulting in insufficient image density.

On the other hand, if the resistance value is too high, charge injection into the toner is insufficient, which tends to cause fogging on images.

As shown in the figure, when the diamond-like coating 20 is formed, the volume resistance thereof is approximately 1QI2 Ωcm as described above, and the resistance value of the blade is approximately 10'' to IQIOΩ, which is advantageous.

(3) As described in detail of the invention, by applying a blade having a diamond-like coating formed at at least one location as the charging means, developing means, and cleaning means, these means are connected to the image carrier and the developing sleeve. By greatly reducing the friction between the blades and reliably preventing blade curling, improving workability, and improving wear resistance and preventing degeneration in high-temperature environments, it is stable over a long period of time. It can carry out tasks such as charging, developing, and cleaning, so it has a remarkable effect on obtaining high-quality images.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of an apparatus for forming a diamond-like film, FIG. 2 is a side sectional view of a cleaning device showing an embodiment of the present invention, and FIG. 3 is a cleaning blade arranged in contact with an image carrier. FIG. 4 is a side view of a charging means showing another embodiment; FIG. 5 is a side sectional view of a developing device showing yet another embodiment; FIG. 6 is a known image forming apparatus. FIG. 2 is a schematic side view showing the configuration. 1... Image carrier, 2... Cleaning device, 3.8
．． 18...Cleaning blade, 7...Charging means, 12...Developing device, 15...Sleeve, 6.1o,
2o...diamond-like film. evil l cause diagram diagram diagram diagram

Claims (1)

[Claims] A moving image carrier, a charging means disposed around the image carrier,
In an image forming apparatus equipped with a developing means equipped with a developing sleeve and a cleaning means, at least one of the means includes a blade that contacts the image carrier or the developing sleeve, and the blade contacts at least the image carrier or the like. An image forming device that forms a diamond-like coating on the contacting parts.