JPS5919954A - Developing method - Google Patents

Abstract

PURPOSE:To improve the stability in the result of development in a developing method which scatters a toner onto the surface of a latent image holding body, by providing the 2nd magnet and correcting the charge on the surface of a developing roll. CONSTITUTION:A magnet roll 4 which supplies a thin toner layer on the surface of a high insulation layer 3 in contact with said layer and the 2nd magnet 5 are provided. A DC bias by a power source 8 and an AC voltage by a power source 7 are applied to the roll 4, and a DC bias by a power source 9 and an AC voltage by a power source 7 are applied to the magnet 5. The DC bias exactly reversed from the bias applied between the roll 4 and a developing roll 2 is applied on the magnet 5. In other words, the biases are so set that minus charge is injected onto the surface of the roll 2 during operation. The formation of the uniform thin layer of the toner is thus made possible, and the stability in the result of the development is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is a development system in which an electrostatic latent image can be visualized by flying non-magnetic, high-resistance toner from developing devices that are disposed apart from each other.
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In the past, various efforts have been made to realize the so-called component development method using non-magnetic toner.
There was something similar to the proposal for /1 tag No. 75. When using magnetic toner, if the relationship with the magnetic pole of the magnetic roller is selected appropriately, so-called ear cutting can be performed completely once.
A uniform layer of toner can be produced on the surface of the magnetic roller as a uniform thin layer. This kind of technology is disclosed in Japanese Unexamined Patent Application Publication No. 2006-11101-1 and 2.
7g/issue, gu/'1.2. Gu 30 No. 7.

II303 No. Otsu, 4t3037 No. ll303g issue,
1963-7g Otsu S Otsu No., /g Otsu S2 No. You can see the /g Otsu 5g issue, /g Otsu 5ta issue, etc.

However, when using a non-magnetic toner, the most difficult problem is creating a uniform thin layer, and no proposal has yet been made that completely solves this problem.

For example, in the case of the above-mentioned published patents, it has been experimentally known that there are many problems such as ζ.

It is a fairly difficult technique to supply toner to a uniform film layer using an uneven roller and to uniformly charge all the toner at the same time. In order to obtain a thin layer of toner due to the use of a textured roller, this must be carried out in combination with a grade, and in order for all of the toner to be It is an essential condition that the toner particles/grains roll against the roller surface. In order to realize the condition that the average particle size of the toner is 70~2
Since the diameter is as small as 0 microns, the mechanical relationship between the solid blade and the uneven roller cannot be implemented, resulting in the use of a rubber-based blade, for example. Go1. When using a type blade, the edge of the grade that has the highest point of blade action is r! It will be pressed against the surface of the n-convex roller, and the grade edge will be in a kind of sanded state. In fact, the biggest problem with this type of system is the extremely short blade life. The next problem is that the strength of the blade pressure causes a strong so-called "spent" of the toner on the roller surface, which is an important factor in preventing snow from charging the toner particles.

Furthermore, problems arise in ensuring various mechanical precisions, and as a result, it is still difficult for this method to be economically viable.

The prototype of the present invention is not a complete/component jump development system. In this sense, it is a combination of the advantages of a two-component system and the advantages of a component system. The advantage of a two-component system is that the use of a carrier allows the toner to fully demonstrate its characteristics by providing a chance for charging between the toner and the carrier. The advantage lies in the fact that the phenomenon results are determined only by the electric field conditions, without being influenced by the toner/carrier mixing ratio or other conditions. In the present invention 1ζ, the condition of uniform charging of the toner by utilizing the large specific surface area of the two-component carrier is maintained, and at the same time, the problem of reliably forming a uniform layer of the toner is solved. - The prefecture uses the same mechanism as two-component development,
Furthermore, it looks like a component jump mechanism will be added to this, but the technical value that can be gained from this is enormous. 1st
It becomes a reality to realize a uniform toner thinness hg on the edge roller surface p. Second, even if there is an oversupply of toner, a function is provided to selectively pick up an effective toner from among the oversupply. The third step is to create a developing machine that does not allow the contaminants coming from the corona discharger to spread throughout the developing machine.

FIG. 1 is a sectional view conceptually showing seven embodiments of the present invention. In the figure, 1 is a carrier that holds an electrostatic latent image, and 2 is a conductive roller having a highly insulating coating M3 on its surface, and the developing roller is placed several hundred microns away from the latent image holding surface. , 4 indicates a magnet and a troller which are in contact with the high insulating layer 3 and supply a thin amount of toner to this surface, and 5 indicates another seven magnets, that is, a second magnet, and each element is shown in the same figure. Is it like that? The conductive part of the latent image carrier is grounded, the developing roller 2 having a highly insulating coating 3 is applied with a DC bias from Wi 6 and an AC voltage from a power source 7, and the magnetic roller 4 is applied with a power source. A DC bias from the power source 91 and an AC voltage from the power source 7t are applied to the other seven magnets 5, and a DC bias from the power source 91 and an AC voltage from the power source 7 are applied to the other seven magnets 5.

The same figure is a plus! This shows a case where body development is performed using a 1-ner that
For example, a DC bias of +100 volts! :
, op, fK O.1: An alternating current voltage with a frequency of / is applied at the root. On the other hand, since the magnetic roller 4 receives AC of the same phase from the power supply 7, even when no AC voltage is applied, there is some AC potential difference. You can also tighten it. Does the potential of the magnet roller 4 and the potential of the developing roller 2 seem to be on the positive side of the DC bias voltage tj8?
This is selected. As a result, the insulating surface of the developing roller 4 can be brought into a state where it is represented by the magnetic roller 4. In general, it is better to place the magnet, roller 4, and roller 2 at the same potential at the same potential.

No matter what kind of developer is used, IL cannot be prevented from injecting a positive charge from the magnet roller 4011 onto the surface of the developing roller 2. For example, in the case of a developer that is a mixture of iron powder and toner, the weight measured at the development site and the relative speed of the two are 2, 3, and -
In the case of , it is assumed that 7 times of surface contact @I・koQ3/microcouloid charge 4ii is injected. The injected charge increases the potential of the surface of the roller 2 by 111
(In order to suppress this shift, the potential difference between the surfaces of the magnet roller 4 and the developing roller 20 is reduced, and the amount of toner supplied to the surface of the roller 2 is reduced.

What if the toner used for Magne and Troller-4 is a component-based toner with low to medium resistance? This charge injection further increases. As a result, the stability of the phenomenon results is significantly 1 to I1. jl! f
be done. Another seven magnets, ie, the second magnet 5, are provided to prevent the development. In terms of DC bias, Magne 7 troller 4 To 1 is used for Magne 5. If the rollers 2 were provided with a space between them, exactly the opposite situation would be given. That is, the setting is such that negative electricity 411 is injected into the surface of the developing roller 2 during operation. Basically, the same amount of opposite polarity charge as injected from the magnet roller 4 is injected into the surface of the developing roller 2, but the developing roller 2 performs a phenomenon operation on the latent image carrier 1. The unexpected charge injection that occurs during the process is also caused by this magnetic roller 4.
It can be erased in one go. For this purpose, it is often effective to apply an appropriate alternating current component between the developing roller 2 and the magnet 5 on average to erase the historical charge distribution on the surface of the developing roller 2.

The frequency to be applied varies depending on the process speed and cannot be determined unconditionally. The effect of adding the second magnet 5 is obvious and strong. The difference between the areas where the second magnet 5 was provided and the areas where the second magnet 5 was not provided was mostly apparent from the first copy, and in areas where the second magnet 5 was not provided, a phenomenon in which the developed density rapidly decreased was observed. This phenomenon has been improved to the extent that it is hardly observed in a system in which an appropriate voltage is applied to the second magnet 5. Regarding the seven examples, the image densities in the area where the second magnet 5 was provided and the area where it was not provided were Z5 and 05, respectively. Furthermore, for confirmation, the result of applying and disconnecting the applied voltage to the first magnet 5 was that the response within 5 seconds was such that a noticeable change in the developer density was observed to the naked eye. was known. If the second magnet does not work, the concentration will decrease unilaterally unless other disarmament is adjusted, and the phenomenon will become impossible for a long time.In contrast, the second magnet When a charge injection effect is given to the magnet 5, if the voltage applied to the second magnet 5 is appropriate, the development result will be completely unchanged, and even if there is some irregularity in the applied voltage, the result will not fluctuate. It is known that the width can be kept extremely small.For example, the width of the second magnet)51
As long as the bias voltage to be applied is in the range of 100 volts to 300 volts, there is practically no problem.

The photosensitive drum that holds the latent image used in this example is:
It is a zinc oxide drum of 2 mm diameter, and the developing roller is 3 mm.
The surface of an aluminum roller with a diameter of 7wnφ is coated with mylar having a thickness of 2jμ.

The magnetic roller is not required to directly generate a latent image, but merely has the function of supplying charged lner to the surface of the developing roller, so the rotating sleeve diameter is 7 mm. By using an extremely thin magnetic roller called φ, the toner and carrier rotation mechanism is extremely simple. The first magnet F used two rod-shaped ferrite magnets wrapped in a thin aluminum plate. As for the seventh problem, there was a tendency for toner to accumulate at the tip of the second magnet, but this was solved by giving the magnet an intermittent vertical motion. For example, in the case of a copy machine, this problem can be solved by simply separating the tip of the magnet from the photosensitive drum for a very short period of time between copies. The experimental conditions are not important, and Q
In order to ensure that the toner is sufficiently replenished on the developing roller, care must be taken to ensure that the latent image has a sufficient visualization density. As per the normal theory of the jump phenomenon, the results are influenced by the values of the AC voltage applied to the developing roller and the DC bias, but these values change depending on the characteristics of the toner, and are not determined experimentally. It is.

In Figure 7, a DC voltage is applied to the second magnet, but even if the second magnet is grounded, it can still function to remove the charge injected by the first magnet. In some cases.

This produces an effect when the resistance of the first magnet is low or when the amount of injection depending on the first magnet is small. or,
If price is not an issue, it is possible to achieve an effect by applying an alternating current.

The same toner and carrier used in the discharge developing method were applied to a copying method using a separately prepared two-component contact developing device, and the differences with the method of the present invention were investigated. In experiments, a two-component contact type developer has a number of 10
While making 0 copies, the initially obtained concentration is lost,
At the same time, fogging of the images began to occur, and this tendency further increased as copying continued.
Even if more than 7,000 copies were made using the method invented by Rikiki,
No difference in image quality was observed. However, in any case, it has been known that when the humidity is raised to about 5% g after multiple uses, the quality of the image deteriorates rapidly. There was a considerable difference in the quality deterioration between the two, with the former exhibiting the same condition as when the developer was extremely deteriorated, and the latter exhibiting the same condition as when the photoreceptor had deteriorated extremely.

When we took out only both developing devices and measured their characteristics, we found that in the case of the contact type, a severe deterioration in the charging characteristics of the carrier was observed, while in the jump type, this was hardly observed. On the other hand, the results of examining the surface of the photoreceptor show that the jump method is more resistant to foreign matter adhesion. As a result of various studies, we found that as long as a zinc oxide photoreceptor is used, it is impossible to prevent ozone generation due to the use of Mylease's corona, and that the contact method cannot prevent the generation of pollutants. It is known that these contaminants that have adhered to the surface of the photoconductor transfer to the developer side, changing the surface condition of carrier 0 in particular and causing developer deterioration. Therefore, it was found that no such phenomenon of agent deterioration occurred.

In the next experiment, a selenium-based photoreceptor was used.

In this case, the polarity of all power supplies was reversed and toner of opposite polarity was used. As a result, a large improvement was observed in the contact type, but when about 2,000 copies were made, a similar degree of deterioration of the developer was observed. It is also known that the ratio deteriorates significantly when humidified. On the other hand, in the case of the jump type, there was no change in image quality even after several 7,000 copies were made, and no change was observed even after humidification. From this, it is concluded that although ozone and contaminants are generated even in a positive corona, as long as this does not get into the developer, no phlegm will occur, and contamination on the surface of the photoreceptor It was thought that it was eliminated at the cleaner stage.

In the example carried out next, two magnetic rollers were used for the roller shown in FIG.
・Used for 5゛, and photosensitive drum 1 and developing roller 2
The conditions were chosen such that the relative velocity of the surface was 01.

This result was more stable in pt than the example of 111[, and had all the characteristics of the so-called touchdown method.

In the next experiment, the computer was assumed to be out, and the optical input section was set to be visualized. A grid was installed between the developing roller and the photosensitive drum, and jump-type developing machines were added. In addition, a charger and an optical image projector were added. The arrangement is as shown in FIG. In the figure, 10 is a special corona discharger to be described later, 11 is for the first incident light, 12 is for the second incident light,
13 is a first developing device that uses toner of a different color from the other seven developing devices, 14 is a grid inserted between the developing roller 2 and the photosensitive drum 1 of the second developing device, and 15 is a grid placed between the developing roller 2 and the photosensitive drum 1 of the second developing device. 16 is a transfer corona, 16 is an AC corona for separation, 17 is a cleaner, and 18 and 19 are power sources for applying alternating current and direct current voltages to the grid, respectively. The gap between the developing roller 2 of the developing device 13 and the photosensitive drum 1 is 0 in the middle.
A grid 14 is provided in which 10 tungsten wire wires of 2 wires φ are stretched at intervals of 2 wires. In this example,
A selenium-based 1 ram is used as the photosensitive drum 1, and the corona charger 10 seems to perform positive charging? It is strained. The first developing device and the second developing device basically have the same structure, but there are some differences in their arrangement.

In the second developing device 13, the developing roller 2 of the first developing device
Whereas the gap between the photosensitive drum 1 and the photosensitive drum 1 is 03,
Since the magnet is located far away from the embroidery, the voltages applied to each part of the phenomenon device, the voltages applied to the first magnet roller 4, etc. are changed accordingly. Basically, the potential relationship between the two magnet rollers 4.5' and the developing roller 2 is the same as in the case of Figure Ω, and the developing roller 2
The electric field strength in the space between the
The roller 2 and the photosensitive drum 1 are selected in the same manner as in the example shown in the figure, and the second phenomenon is carried out by the roller 2 and the photosensitive drum 1. Gu! J y l') The role of the applied alternating current and direct current voltages is described in U.S. Patent 3g.
As seen in No. 93'l1g, the purpose of this is to control the behavior of toner during the rt migration process, eliminate background noise during development, and increase the toner adhesion density in the area to be developed. The operation of this grid plays a major role in ensuring that the results developed in the first phenomenon device are not spoiled by the first phenomenon device. If the result of the phenomenon in the first developing device is 1g73g of the first developing unit, then the first current @! If the operation result of Rg is impaired and the shape is changed so that two types of toner are mixed and absorbed, the result of combining both will be that the two types of toner will gradually mix and eventually the color discrimination ability will deteriorate. The direction of losing [not to be discouraged] In other words, it is considered that the route through which the toner provided in the first developing device is transferred to the first developing device must be cut off.

The area shown in Figure 3 is one way to concretely realize this.
It must satisfy the condition that the result of the visible image once created by the first developer 1 does not change by the second developer.

Among the multicolor electrophotographic hojos that have been proposed so far, the one that could actually be used is U.S. Patent 3g1l/7! ;/ This method is the only method shown in &11 of the present invention.
It does not form one visible image of different colors one after another on the photoreceptor, but every time the processing of seven colors is completed, the surface of the photoreceptor is wiped and the next color is applied. Moving on to the process, that is, the transfer process necessarily requires as many colors as there are colors. This is a time l
It cannot be used in situations where shortening of is most necessary.

In his experiments, the goal was to first develop a first color, and then develop a second color on the photoreceptor that retained the first color. It is assumed that the colors ] and so have the same polarity. This means that even if you add a third color, you will still get the same result.

The results of the experiment show that the image forming result depending on the first developing unit is different from that of the second developing unit.
It was shown that the toner image of two colors can be transferred and discharged in one process. This condition persisted through one long drive of 70 hours. Of course, if you set the third developing device the same as the second developing device,
A third color may be superimposed.

[Brief explanation of drawings]

FIG. 1 conceptually illustrates an embodiment of the method related to the present invention 1.
A sectional view showing this. FIG. 2 is a partial sectional view showing a type using two magnetic rollers same as above. FIG. 3 is a side view showing a type to which a jump developing machine is added. In the figure, reference numeral 1 denotes a support for holding a sub-1ψ, 2 a virtual roller having a highly insulating coating 3, and 5.5' a second magnet.

Claims (1)

[Claims] A single layer of toner is uniformly formed on the insulating layer surface of a conductive developing roller having a highly insulating coating using a two-component developer.
1. A latent image holding surface disposed spaced apart from the developing roller. A method for causing toner to fly from the surface of the developing roller. The present method (2) is characterized by supplementing the surface charge of the surface.