JPS62242975A - One-component developer - Google Patents

Abstract

PURPOSE:To form a uniform thin layer of a developer on a developer carrying body and to apply a substantial electric charge to the developer by setting the roughness of the surface of a soft elastic material of a layer forming member to be brought into press-contact with the developer carrying body to a specific range. CONSTITUTION:The layer forming member 10 to be pressed to the developer carrying body 5 is formed by adhering the soft elastic material 12 to an elastic material 11. The surface roughness of the soft elastic material 12 to be pressed to the developer carrying body 5 is set in a 0.3<Ra<3mu range when the center line average height thereof is designated as Ra and further the surface of the layer forming member 10 to make contact with the developer carrying body 5 has a rugged shape of curvature R in the transverse direction of the layer forming member 10. The curvature R thereof is so determined as to have the relation Rd<=R<=2Rd. The formation of the thin layer of the developer and the operation for applying the electric charge by frictional electrostatic charge are then satisfactorily executed even if the soft elastic material 12 wears with lapse of time.

Description

[Detailed description of the invention]

(Industrial application field) The present invention is applicable to electrophotographic copying machines and electrostatic printers.

[J
Regarding one-component development equipment that forms an electrostatic latent image as a visual image, in particular, it is used to form a thin layer of developer on a developer carrier and to impart an appropriate charge to the developer. The present invention relates to a one-component developing device using a layer forming member used for. (Prior art) The developing device used in conventional electrophotographic copying machines, etc.
Apparatuses employing a cascade development method, a magnetic brush development method, a liquid development method, etc. are widely known. Conventionally, in developing devices that employ these developing methods, toner made of powder is mixed with fine powder such as magnetic powder, lint, or glass beads, or paint made of fine particles. A so-called two-component developer is used. However, in the case of a two-component developer, the toner is given a charge (=J, but from 1 to )-
- The charging characteristics of the carrier tend to deteriorate as the carrier is used for a long period of time, which may cause fogging on the background of the copy image. It was necessary to replace it with a new one. In addition, with two-component developers, it is necessary to maintain the mixing ratio of toner and carrier A7, that is, the toner concentration, within a certain range, which requires more frequent maintenance, which requires time and effort. It has the disadvantage that it requires a lot of energy. In recent years, as a developing method aimed at reducing the frequency of replacing the developer as described above, methods such as 1, which do not etch the carrier, have been developed.
~ A one-component development method that uses a developer consisting only of
It was created in h format so that it could be used in some types of copying. The two-component developers used for this are roughly divided into magnetic component developers and non-magnetic component developers. Of these, non-magnetic component developers have high transparency, so they are suitable for color development. It is said that when applied, it can bring about a good ending. As a developing method using this -If la-component developer, the "touchdown developing method" disclosed in US Pat. No. 2,895,847 is generally well known. However, although this developing method is easy, it requires large equipment, and
Since the discharging action of a charged corotron is used as a means to impart an electric charge to the developer, COD is periodically applied.
It is necessary to clean 4m of the on-wire. Therefore, when using this method, there are many drawbacks in terms of maintenance and copy image quality. Furthermore, as other prior art using the -component development method,
JP-A-47-13088, JP-A-47-1308
The Imprefushicon development method disclosed in Publication No. 9 is well known. However, even with this Imprefushicon development method, in order to obtain a higher quality copy image, it is necessary to form a uniform and thin layer of toner on the pressure development surface and impart an appropriate charge to the toner. Furthermore, in addition to the above-mentioned method, a non-contact transfer and development method has been proposed; In order to develop, it is necessary to regulate the development gap to 0.05#I or less, which poses many difficult problems in terms of mechanical N marks on the photoreceptor and donor.To solve this problem To, Japanese Patent Application Publication No. 1973-305
As shown in US Pat. No. 37, US Pat. No. 3,890,929, and US Pat. No. 3,893,418, a method of applying an alternating electric field between a photoreceptor and a donor is used. The developer used in the one-component development method described above is non-magnetic.
Since it is a component developer, it forms a uniform developer 719m on the developer carrier, and each l/toner of the developer retains a sufficient charge so that ffl! It must be transported toward the electrostatic latent image, but these points are discussed in the patent application filed in 1983.
This has been improved by using the developer carrier and the single-layer forming member 1 to 1 disclosed in Japanese Patent Application No. 155092 and Japanese Patent Application No. 155093/1983. Furthermore, as a one-component developing device that has been commonly used in the past, an apparatus as shown in FIG. 14 is known. (Refer to Japanese Unexamined Patent Publication No. 61-29866) In the example shown in FIG. 14, the developer 3 is stored in the hopper 2, and the developer carrier 5 and the developer carrier A developer supply member 6 for supplying developer to the developer supply member 5 is provided. Then, the layer forming member 10 is brought into contact with the upper surface of the developer carrier 5, thereby supplying the developer thin layer 4 to the development area, and the layer forming member 10 is applied to the developer thin layer 4. It is possible to charge an electric charge of a predetermined polarity by friction with the metal. The developer carrier 5 and the developer supply member 6 rotate in the directions of arrows Δ and B, respectively, and are moved in the same direction at their contact portions, and the developer 3 is transferred to the developer carrier 5 by the developer supply member 6. will be moved to Then, the developer layer formed on the developer carrier 51 as described above is pressed by the layer forming member 10 to form a thin layer, and frictional electrification is performed during the sliding of the developer layer to a predetermined level. A thin layer of developer having a charge of The layer forming member 10 used in this embodiment is a member constructed by joining a soft elastic body 12 to an elastic body 11 such as a plate spring, and its upper end is fixed to a support body 15, and the elastic body 11 is The developer carrier 5 is pressed with a constant pressing force using elasticity.
is designed to be in contact with the surface of the The contact pressure is set at a linear pressure in the range of 50-500 g/cm, and keeping this pressure constant keeps the thickness of the thin layer of developer constant. This is important in order to prevent the occurrence of disturbances in the copied image, fog in the background, etc. (Problems solved by the invention) However, according to the conventional one-component developing device, when the layer forming member is brought into contact with the developer 11, the developer is charged with a desired polarity. (=I) However, while the surface of the developer I11100 is a curved surface, the surface of the soft elastic material of the layer forming member that comes into contact with it is approximately linear, as shown in FIG. , or the two members are in contact because they are formed as curved surfaces curved in opposite directions;
This results in a relatively short period of time for friction against the developer. Therefore, depending on the above-mentioned action, for the developer,
There are disadvantages in that a sufficient charge cannot be applied and it is difficult to form a uniform layer. Therefore, the developer may adhere to the non-image area of the electrostatic latent image carrier, resulting in the formation of a so-called "fogged" copy image. In addition, if sufficient charge cannot be given to the developer, the pushing force of the layer forming member 10 will not form a thin layer with a uniform thickness, and the developer on the developer carrier will , because it is not sufficiently electrostatically supported, the developer surface developer may spill on exposed areas around the developing area, thereby damaging other devices around the developing device. There was a problem with getting it dirty. Generally speaking, in conventional layer forming members, when used for a long time, the surface portion of the soft elastic body pressed against the developer carrier wears out, and arc-shaped depressions are formed in the longitudinal direction. When such a state occurs, the contact area of the soft elastic body increases compared to the initial state, and therefore the maximum stress when forming the developer wJWJ is reduced, and as a result, the thin layer The thickness of the printed material increases, which may cause fogging at the spine or uneven density on copies. (Object of the Invention) The present invention solves the above-mentioned drawbacks of conventionally used developing devices, and provides sufficient charge to the developer formed as a thin layer on the surface of the developer carrier. A means for forming a layer of a predetermined thickness is provided, thereby producing a visible image having a homogeneous image density with little fog on a nine-electrolayer image carrier. The purpose is to provide a device that can form images. (Means and effects for solving the problems) The one-component developing device of the present invention avoids contact of the layer-forming PlI material with the developer carrier that supplies the developer to the electrostatic latent image holder. The developer layer is formed as 39 layers with a predetermined thickness, and a predetermined charge is applied, and the developer formed in the thin layer is transferred to the development area and placed in the static charge on the D electrostatic holder. This device is configured to selectively apply electrostatic latent images and develop them. In the apparatus of the present invention, the roughness of the surface of the soft elastic body pressed against the developer carrier of the layer forming member is 0°3<Ra<3μ, where the center line average roughness is Ra. The range is set to . In addition, even if the surface of the soft elastic body where the layer forming member comes into contact with the electrostatic latent image holder is worn out over time and the surface □ is scraped, the surface of the soft elastic body where the layer forming member is in contact with the electrostatic latent image holder will be damaged. The roughness is configured to be in the range of 0.3<Ra<3μ. Further, a concave portion with a radius of curvature R is formed in the soft elastic body of the layer forming member that is in contact with the surface of the electrostatic latent image holder, and the radius of curvature R of the concave portion is set in the range of Rd≦R≦2Rd. Therefore, in the one-component development system of the present invention, by specifying the surface roughness of the soft elastic body pressed against the developer carrier, when forming and covering the three layers of developer, it is possible to By making it possible to apply a sufficient charge and to form a pressing part with a roughly constant area at all times, uniform n9F! 4 can be formed. As a result, it is possible to make a clear copy, and it is also possible to prevent defects such as staining the surrounding area of the image. (Example) The configuration of the C1 one-component developing device of the present invention will be described according to the illustrated example. Desirable one-component developing devices to which the present invention is applied include:
An apparatus such as that shown in FIGS. 1 and 2 is used. In this example, the developing device includes a hopper 2 containing a developer 3, and a developer carrier 5 installed in one part of the hopper 2.
and a developer supply member 6 for supplying developer to the developer carrier 5. Further, the layer forming member 10 in contact with the developer carrier 5 is a member for suppressing and applying friction to the 11 layers of developer 3 deposited on the surface of the developer carrier 5. The developer sheet FI4 deposited on the developer carrier 5 is formed to have a uniform thickness, and a sufficient charge can be applied to the developer by friction. Then, a thin layer of developer formed on the surface of the developer carrier 5 is caused to fly against the static ff2 latent image in a development area opposite to the electrostatic latent image of the electrostatic latent image holder 1, and It is possible to turn an electrostatic latent image into a visible image. The developer supply member 6 used in the embodiment of the present invention is made by adhering an ethylene propylene dye material (EPOM) rubber layer to the outer periphery of a stainless steel core, and is pressed against the surface of the developer carrier 5. while being rotated. The developer carrier 5 is formed by coating the surface of a solid or hollow cylindrical member made of iron with a phenol resin as a semiconductive resin to a thickness of, for example, 1 m. The layer forming member 10 has a structure as shown in FIG. 2, and is formed by adhering a soft elastic body 12 to an elastic body 11. The soft elastic body 12 is made of a base material made of silicone rubber or the like containing a chromium complex dye. In addition, the base materials of the soft elastic body include silicone rubber, ethylene propylene rubber, styrene butadiene rubber,
It is desirable to use a JIS standard rubber hardness of 10 to 70 degrees, such as 0% polypropylene rubber. Further, as the elastic body 11, it is desirable to use a plate spring material made of phosphor bronze, silicon steel, stainless steel, etc. and having a plate thickness of 0.03 to 0.511 II. Therefore, the developer 3 in the hopper 2 is transferred to the developer carrier 5.
After being frictionally charged and charged by the friction between the developer supply member 6 and the developer supply member 6, the developer is transferred toward the layer forming member 10 while adhering to the surface of the developer carrier 5, and the layer forming member 1
0, it is formed as a thin layer of a predetermined thickness, and its II! ! By rubbing, a sufficient charge with a predetermined power is applied. The thin developer layer 4 formed in this manner is rotated while applying a Vi flow superimposed AC bias voltage to the developer carrier 5, thereby being sent to the development area facing the electrostatic latent image carrier 1. The electrostatic latent image formed on the surface of the electrostatic latent image carrier 1 and the developer carrier 5 fly toward the electrostatic latent image in the development area, and the electrostatic latent image is It is deposited on the latent image to form a visible image. (Function) According to the present invention, the surface roughness Ra (center line average roughness) of the soft elastic body 12 of the layer forming member that contacts the developer carrier 5
Since 0.3<Ra<3μ, the developer that has been triboelectrically charged due to the friction between the developer carrier 5 and the developer supply member 6 can be sufficiently charged by further rubbing against the soft elastic body 12. The developer can be reliably carried on the developer carrier 5 to which a predetermined bias voltage is applied, and at the same time, a uniform thin layer 4 of the developer can be formed on the surface of the developer carrier 5. It becomes possible to form. In this manner, when the sufficiently charged thin layer of the developing device faces the developing area of the electrostatic latent image carrier 1, the electrostatic? Depending on the electrostatic latent image on the holder 1, an appropriate amount of developer adheres to the electrostatic latent image, and unnecessary developer is prevented from adhering to non-image areas. Therefore, when the toner image on the electrostatic latent image holder is transferred onto paper, a clear copy image with less capri is obtained. However, in the developing device of the present invention, the layer forming member 10
By applying a -1 minute charge to the developer ((1!O'J), a thin layer of developer is formed on the surface of the developer carrier 5 with a relatively strong adsorption force. There is no need to worry about the developer spilling around the ?I and snow contaminating the surrounding area.
As mentioned above, since a layer of semiconductive phenolic resin is formed, when using a dye containing chromium complex dye, the maximum bf! A single layer of tofu was formed, and a high-quality copy image was obtained. In general, in the present invention, equally good results could be obtained with either Jr magnetic or magnetic 1-ner. Example 1 The elastic body 11 of the layer forming member 10 is made of stainless steel SU
Plate thickness 0 consisting of S 304 c s 3 / 41-1
．． The soft elastic body 12 is made of a 1m plate spring material, and the soft elastic body 12 is JIS rubber hard I! ! The base material was 50 degree silicone rubber, and 1.0% by weight of TRH (trade name) as a chromium complex salt dye was contained in the base material. As a method for manufacturing the layer forming member 10, first, the soft elastic body 1 is
As the silicone rubber base material of 2, KE650-Ll, KE
850-U, KE554-U, KE555-U, KE7
52-U (manufactured by Shin-Etsu Silicone Co., Ltd.), TS
Heat-vulcanized silicone rubber such as E221, TSE270゜TSE260 (manufactured by Toshiba Silicone Corporation) is used alone or in combination, and the TRH is kneaded into this silicone rubber using a mixer consisting of three rolls. This is put into Jil+, heated and vulcanized, and then cooled to form a rubber. The rubber obtained in this way is cut into a piece with a thickness of 1 shoe and a width of 1 shoe.
The soft elastic body was cut into pieces with a length of 300 m and was heat-pressed onto the surface of the leaf spring of the elastic body 11 using an adhesive. The layer forming member 1o composed of the elastic body 11 and the soft elastic body 12 thus obtained was attached to a developing device as shown in FIG. As developer 3, positively charged MI-NO containing nigrosine dye and carbon in a styrene acrylic binder was used. The developer carrier 5 was driven at a peripheral speed of 127 m+/sec. By changing the surface roughness of the mold after kneading the soft elastic body with ;b of the above-mentioned set ribs, the surface roughness of the portion of the layer forming member in contact with the developer carrier was changed. Thereby, after passing through the layer forming member for each surface roughness,
The charging properties of the developer on the developer carrier and the state of thin layer formation were investigated. As a result, as shown in FIG. 3, the surface roughness Ra of the soft elastic body in contact with the developer carrier is 3.
In the case of μ or more, the average charge F11 was low and a thin layer was not formed uniformly and stably. Moreover, the results of examining the limit conveyance amount (conveyance m that allows layer formation) for each roughness are shown in FIG. As is clear from FIG. 4, when the center 12'I7 uniform roughness Ra of the layer forming member in contact with the developer carrier 16 is 0.3 μ or less, the limit conveyance amount is small and applicable. Go out of range. From the above results, the average roughness Ra is 0.3<Ra<3
It has been found that it is desirable to set it in the range of μ. In addition, as a result of copy testing in this range,
I was able to make clear copies with no fog. Also, under the above setting conditions, the print test 1
As a result of performing ~, it is possible to obtain clear copies without fogging when the surface roughness of the pressure contact portion of the soft elastic body of the layer forming member is 0.3<Ra, as shown in Fig. 5. <3
It is in the range of μ. In another embodiment of the present invention shown in FIGS. 6 and 7, the configuration of the main members of the developing device is almost the same, but the soft elastic body 12 of the layer forming member 10 is replaced with the one described above. It is formed as a change compared to . In other words, in this example, as shown in FIG.
A recess 1 is formed on the surface of the soft elastic body 12 that is in contact with the developer carrier 5.
3 is formed. Therefore, in this example, if J3 is used,
The concave portion 13 of the soft elastic body 12 comes into pressure contact with the surface of the developer body 5 over a wide range (・Developer body 5), and each forms a thin layer of developer and applies a charge by try ta charging. Example 2 In the developing device shown in FIG. 6, as the developer 3,
Azo dye double constant% in styrene acrylic binder,
A negatively chargeable toner (average particle size: 12 μm) containing 910% by weight of carbon bluff was used. The developer supply member 6 was made of a stainless steel core with an EPDM rubber layer adhered to the outer periphery, and the developer carrier 5 was a roll made of commercially available phenol resin. The layer forming member 10 is made of silicone rubber with a hardness of 50 degrees as a soft elastic body 12, and 1.0% monoethanolamine is kneaded into this using three rolls, and the mixture is placed in a mold and heated and vulcanized. After cutting, the thickness is IHR1 and the width is 10111111.
．． It is formed into a plate shape with a length of 300#+III, and has an elastic modulus of 2. 1X10 K9/ci, 0゜thick, glued to standard stainless steel (SLJS304csp3/4N O), and furthermore, the contact part with the developer carrier has a width of 6 ttm and a radius of curvature R = 16. Prisoner (R=1.0
7XRd) with a concave part and one without a four part (] [= A copy test was conducted with the weights being equal and the circumferential speed of the developer carrier 5 being 200 m/sec. Figure 8 shows the changes in the surface roughness of the soft elastic body of the layer forming member when copies are made up to 200,000 sheets, and 1ffl of developer per medium area conveyed through the layer forming member is shown in Figure 8. It is shown in Figure 9. As seen in these figures, in the initial state, the wear of the soft elastic body and the change in shape are smaller in the case with the recessed part than in the case without the recessed part, and the amount of developer conveyed ( The small amount of developer per unit area of the developer carrier that is sent through the layer forming member increases gradually in the case where the recess is not provided compared to the case where the recess is provided, as shown in the figure. Copy 1 +a turned upside down and fog appeared on the back. On the other hand, when the layer forming member is provided with four parts, the shape after wear is almost the same as the initial state, and therefore the stress distribution is also kept almost the same as the initial state.
During copying of 200,000 sheets, the color was almost constant, and no fogging occurred on f11. (Figure 10) Next, the same test as above was conducted by changing the radius of curvature of the four parts formed on the surface of the soft elastic body of the layer forming member. Fig. 11 and Fig. 12 show the results of a and background fog. As can be seen from these figures, the radius of curvature R is R≦2R
It can be seen that in case d, copies in good condition without fogging can be obtained for a long period of time. In addition, in the case of R<Rd, it was found that the contact shape with the developer carrier became complicated and layer formation became constant during the above test, which was not preferable. In the end, in the layer forming member of the present invention, it has been found from the above results that it is possible to obtain good results when Rd≦R≦2Rd. In addition, the maximum stress when the developer weight per unit area on the developer carrier is 0.7 #19 is approximately the same value even if the outer diameter of the developer carrier is different. As shown in Figure 13, it was found that As described above, in the one-component developing device of the present invention, the surface roughness of the soft elastic body provided in the portion of the layer forming member that contacts the developer carrier and the radius of curvature of the surface are separately defined. It has been found that each of these requirements is effective, and it is naturally possible to apply these requirements separately, but when forming a layered member by combining the two requirements above, the effect can be further enhanced. Of course, it is possible to perform. (Effects of the Invention) Since the one-component developing device of the present invention is configured as described above, the layer forming member provides sufficient 'dX front to the developer held on the developer carrier. (-J'
When it becomes possible to i, due to the charge,
It becomes possible to form a uniform thin layer. Therefore, in the one-component developing device of the present invention, it is possible to obtain an appropriate development density depending on the electrostatic latent image on the electrostatic latent image holder, and also to develop the non-image area. This means that it is possible to reliably prevent the occurrence of blur caused by the adhesion of the agent, and it is possible to obtain clear images. In addition, since the developer is strongly electrostatically attached to the developer carrier, the developer does not spill out, so that it is possible to reliably prevent the surroundings of the developing device from being contaminated.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of the developing device of the present invention, FIG. 2 is a sectional view showing the configuration of the layer forming member of the present invention, and FIG. 3 is a diagram showing the layer forming member in contact with the developer carrier. FIG. 4 is a graph showing the relationship between the center line average roughness Ra of a portion and the developer average tribo, and FIG. A graph showing the relationship, Figure 5, is the relationship between the number of copies and the roughness of the layer forming member,
and a graph showing the state of the test at that time, FIG. 6 is a schematic configuration diagram of a developing device in another embodiment of the present invention, and FIG.
The figure is a perspective view showing the structure of the layer forming member used in the apparatus shown in FIG. 6, FIG. 8 is a graph showing the relationship between layer forming r'J5 wear m and the number of copies, and FIG. Current Q71 per unit area conveyed through the layer forming member
FIG. 10 is a graph showing the relationship between the copy density and frontal fog and the number of copies, which corresponds to FIG. A graph showing the relationship between the radius of curvature R of the four formed parts and the developer carrier after an operation equivalent to copying 200,000 copies, and FIG. Graph showing the relationship with the amount of transported developer, 13th
The figure shows the middle part of the layer forming member - developer E per area is 0.7
14 is a graph showing the relationship between the maximum stress resulting in ay and the outer diameter of the developer I'll carrier, and FIG. 14 is a schematic diagram showing the structure of a conventionally used developing device. Reference numerals in the figure 1...Electrostatic latent image holder, 2...Hopper, 3...Developer, 4...Thin layer, 5...
...Developer carrier, 6...Developer supply member, 10...Layer forming member, 11...Elastic body, 12... Soft elastic body, 13... recess, 15... support body. Agent: Takeshi Shimizu; (1 other person) Fig. 1 Fig. 2 Ritsufusuma 3 Fig. 15 tj Part of melon part drawn in 1 area Copy school table RCXRD) High school 12th figure, 13th figure

Claims (2)

[Claims] (1) By bringing a layer forming member into contact with a developer carrier that supplies developer to an electrostatic latent image carrier, a developer layer is formed as a thin layer with a predetermined thickness, and a predetermined charge is formed. selectively applying the developer formed in the thin layer to the electrostatic latent image on the electrostatic latent image carrier in the development area,
In a developing device configured to perform development, when the surface roughness of at least the portion of the layer forming member that is in pressure contact with the carrier is defined as the center line average roughness of Ra,
A one-component developing device characterized by setting the range of 0.3<Ra<3μ. (2) The contact surface of the layer forming member with the developer carrier has a concave shape with a curvature R in the width direction of the layer forming member, and the curvature R has the following relationship. A one-component developing device according to claim 1. Rd≦R≦2Rd, where R: radius of curvature of the recess of the layer forming member, Rd: radius of curvature of the developer carrier,