JPH05127511A - Developing device - Google Patents

Abstract

PURPOSE:To eliminate the unevenness of a density, a level difference, void, and the nonefficient consumption of a developer, to improve the image quality of an electrophotograph and to stabilize a device by giving roundness to a surface state having a sharp projecting part by means of the surface processing of a developing sleeve and stabilizing the regulation of a developer quantity. CONSTITUTION:This developing device having a fixed magnet body (magnet roller) 4, a developer carrier (developer sleeve) 3, having the magnet body 4, inside, carrying the developer on the surface and having rigidity, and a bar-like developer quantity regulator 5 which is made of a material having the rigidity on a pressing part against the carrier 3, simultaneously, has 0.5-15mm curvature radius on the pressing part, and regulates the quantity of the developer carried on the carrier 3, in such a manner that the regulator 5 is opposed to the magnet body 4, pressed on the carrier 3, is constituted so that the surface of the developer carrier 3 carrying the developer has ruggedness forming processing, and the glossiness of the surface is set 2-1400%GS (20 deg.), as a feature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device applicable to the development of a latent image on an image forming body, particularly an electrophotographic image forming apparatus.

[0002]

BACKGROUND OF THE INVENTION In an electrophotographic image forming apparatus using a one-component or two-component developer, a developer on a developer carrier (also referred to as a developing sleeve or simply sleeve) is used in order to obtain a good image. It is necessary to make the layer thickness of 2 thin and uniform.

Conventionally, as a developer amount regulating body (also referred to as a developer layer thickness regulating member), the layer thickness is regulated by a fixed regulating plate which has been used for a long time, but the developer carrying body and the fixed regulating plate are regulated. There is also a limit to mechanical mounting accuracy, etc., and the layer thickness is about 0.3 mm as the lower limit. Moreover, it was difficult to obtain a uniform and uniform thin layer by this method. However, various developer layer thickness control devices other than the fixed control plate have been devised to meet the purpose of obtaining a uniform thin layer. For example, the following may be mentioned.

(A) In the developer layer forming apparatus described in Japanese Patent Laid-Open No. 54-43038, when a one-component toner is used, a developer carrying member is composed of a plate-like elastic body having a free end on one side. The material layer thickness regulating member is bent and pressed.

(B) The developer layer forming apparatus described in Japanese Patent Laid-Open No. 54-51848 uses a plate-like elastic body in which a metal spring and a soft elastic body are superposed, and the plate-like abdomen of the soft elastic body is used as a developer. By pressing against the carrier, the layer thickness of the one-component developer is regulated.

(C) The developer layer forming apparatus described in JP-A-59-126567 and JP-A-59-129879 is also intermittent with a developer carrier in a developing apparatus using a one-component developer. Alternatively, a continuously rotating elastic roller is pressed to regulate the layer thickness of the developer by the nip between the two.

(D) In the developer layer forming apparatus described in Japanese Patent Publication No. Sho 60-12627, in a developing apparatus using a one-component developer, a rotating roller is brought into contact with a developer bearing member made of an elastic body so that the developer It controls the layer thickness.

(E) JP-A-62-191868 and JP-A-62-191868 which have been improved so as to be used in a two-component developer.
Japanese Patent No. 191869 discloses a technical means for forming a thin developer layer on a developing sleeve suitable for non-contact development.

This is because the tip of the elastic plate supported by the supporting member is directed in the upstream direction of the movement of the developer on the developing sleeve, and the elastic plate is pressed onto the developing sleeve.
As a result, the layer thickness of the developer including the magnetic carrier and the toner that is attached to and conveyed on the developing sleeve is regulated, so that the developer layer thickness can be easily made into a thin layer with high accuracy as compared with the conventional regulation means. It can be set. (F) Similarly, a two-component developer is used.
In the developing device described in JP-A-189582 and JP-A-62-75563, a solid plate-like layer thickness regulating member is provided, a magnetic body is arranged on the back surface thereof, and the attraction force of a fixed magnet body provided in the developer carrying body is used. There is disclosed a device that indirectly presses the abdomen or the bent edge of the regulation plate to regulate the layer thickness.

(G) Further, in Japanese Patent Application Laid-Open No. 2-50184, the present applicant has disclosed a technique for controlling the layer thickness by means of a pressure regulating magnetic rod having rigidity.

[0011]

DISCLOSURE OF THE INVENTION The drawbacks of the above-mentioned conventionally proposed developer layer forming apparatuses are as follows. Since both the devices (a) and (b) utilize the pressing force generated by bending the layer thickness regulating member made of an elastic body, the pressing force is the rotational speed of the developer carrier, the pressure contact position, and the developer. It is liable to change due to fluctuations in the layer thickness, etc., and easily vibrates. Moreover, since no means for suppressing the vibration is provided, it vibrates in resonance with the vibration generated in the image forming apparatus, which results in uniform vibration. There is a problem that it is difficult to obtain a developer layer having a uniform thickness. Further, especially in the device (b), since the soft elastic body presses, this tendency is remarkable, and the geometrical shape of the abutting portion (nip) is further determined by the rotational speed of the developer carrier, the pressure contact position, and the developer. Perturbation is likely to occur due to fluctuations in the layer thickness and the area of the nip changes. Therefore, there arises a problem that the thickness of the developer layer tends to be uneven. In addition to such inconvenience, when one or both of the nip is made of a soft elastic body, there is a disadvantage that clogging of the nip with the developer and variation of the (soft) elastic body with time occur over time. These disadvantages are likely to occur especially in the case of a developer containing a hard material such as a magnetic material or a fluidizing agent. Further, in the apparatus of (c), a more stable and uniform thin layer can be obtained than in the case of (a), but since the layer thickness regulating means by the rotating body is used, it is possible to loosen or agglomerate the agglomerated particles of the developer. In such a case, the performance is inferior, and the phenomenon that the agglomerates of agglomerated particles are sandwiched in the nip portion and it passes through with the rotation of the rotating body occurs, and the performance that is always satisfactory even with the intermittent rotation is obtained. However, the image quality deteriorates due to image stains and black spots. Also, in order to balance the pressure, the rotating mechanism, the pressure contact mechanism, etc. were complicated.

Further, in any of the devices (a) to (d), in a normal developing device in which the pressing area of the layer thickness regulating member is relatively large and the amount of developer fed to the nip portion fluctuates moment by moment, There is a drawback in that such a variation is reflected to give a developer layer thickness that changes moment by moment.

(C) and (d) are suitable for non-magnetic one-component developers, the developer carrier has elasticity, and a developer layer thickness regulating member is pressed against this to form a thin layer of developer. This is a technique for permanent deformation of the developer carrier, and the elastic modulus of the developer layer thickness regulating member is likely to change over a long period of time, and stable layer formation cannot be achieved.

Even in the case of (e) developed for two components, it is not possible to maintain sufficient characteristics in long-term use.

Further, in (a), (b), (e) and (f), the elastic developer layer thickness regulating plate is pressed against the developer carrier (metal sleeve) having rigidity to form a thin layer. Therefore, the elastic modulus change of the elastic plate during long-term use,
It has a drawback that permanent deformation is likely to occur and durability as a layer thickness regulating member is short. Moreover, when the elastic plate is attached, if its position changes slightly, the amount of tip play and
The pressing force changes and it is difficult to achieve stable layer thickness regulation. Therefore, it has a serious drawback that the mounting accuracy is extremely strict during mass production.

Further, particularly in (f), although the effect of unraveling toner aggregation by the magnets arranged on the back surface of the developer layer thickness regulating member and inside the developer carrying member works a little, the solid plate-like regulating member is used. Since the attraction force through the magnet is used, the attraction force decreases sharply as the distance between both magnets increases, and it is easy to spread the pressure variation due to the distance variation, and the pressure effect on the developer layer is stable and uniform. However, the toner or the agglomerate of the developer may pass through, or, on the contrary, a constant layer thickness may not be obtained, which may cause an adverse effect such as an eye spot and a white stripe on the image quality.

Although (g) was able to solve many of these problems, it was still insufficient and left a very important problem. That is, in recent years, the adoption of color toner and the like, and the lowering of the softening point of toner have been promoted aiming at energy saving and low power consumption. In that case, the toner itself may be melted by the rubbing between the developing sleeve and the developer amount regulating body, and stick to the stick of the developing sleeve or the developer amount regulating body. that is,
Generally, the surface of the developing sleeve that has been ground has irregularities having irregular sharp projections as shown in an enlarged view of the surface state of FIG. 19, which allows the developer to be conveyed, but is too sharp. Therefore, it was easy for frictional heat to occur. If toner sticks or the like, the carry amount changes, which causes serious problems such as uneven density and reduced density.

The above is rare, and if it does not occur, no surface problem occurs, but if it happens, it will be serious. Occasionally, such defects are unacceptable.

In the present invention, in order to solve these problems and stably form a good image, the developer layer on the developer carrying member is formed to have a uniform layer thickness and is stably formed. It is an object of the present invention to provide a developing device capable of preventing toner from moving to a developing area.

[0020]

This object is achieved by any one of the following technical means a, b, c, d and e.

(A) A fixed magnet body, a developer carrying body which has the magnet body inside and has a rigidity for carrying a developer on the surface, and the developer carrying body facing the magnet body. In a developing device having a rod-shaped developer amount regulating body which is pressed against the body and regulates the amount of the developer carried on the developer carrying body,
The developer amount regulation body is a material whose pressing portion against the developer carrying body has rigidity, and the pressing portion has a radius of curvature of 0.5 to 1
The surface of the developer carrying member is 5 mm, and the surface carrying the developer is subjected to a concavo-convex forming treatment, and the glossiness of the surface is 2 to 1400% Gs.
(20 °) developing device.

(B) The developing device as described in the item (a), wherein the unevenness forming process is a spherical grain blasting process.

(C) The developing device as described in item (a), wherein the concavo-convex forming process is a spherical grain blasting process after an irregular grain blasting process.

(D) The developing device as described in the item (a), wherein the unevenness forming process is a wrapping process using a wrap film after the irregular grain blasting process.

(E) The developing device according to any one of a, b, c and d, wherein the pressing portion has magnetism.

[0026]

According to the present invention, the surface of the developer carrier (developing sleeve) having rigidity is subjected to unevenness treatment so that the glossiness thereof is within the above range, and the rod-shaped non-magnetic member or magnetic member having rigidity is used as the developer. It was possible to form a stable thin layer by pressing as a quantity control body.

In the present invention, having rigidity means having a large rigidity, that is, a rigidity of 10 ⁴ kg / cm.
² or more, specifically (0.8 to 1.6) x 10 ⁶ kg / c
Contains iron, which has a rigidity of about m ² , and various magnetic metals such as its alloys, and magnetic powder (1.0 to 10)
A hard resin having a rigidity of about 10 ⁴ kg / cm ² can also be used as the developer amount regulator of the present invention. Further, iron and iron alloys plated with chromium or the like are also used.

Further, having magnetism means having a property of being attracted to a magnet.

The present inventors have already conducted the following experiments.

Using the experimental apparatus as shown in FIG. 1, layers were formed by using magnetic and non-magnetic cylindrical rods 50. That is, the magnet roller 4 having a plurality of magnetic poles was fixed, and the developing sleeve 3 was rotated in the arrow direction on the outside thereof. A cylindrical rod 50 was pressed against the developing sleeve 3 by using a spring stopper. The pressing position of the cylindrical rod 50 was set at a position facing the magnetic pole of the magnet roller 4. When the parameters were the pressing force of the cylindrical rod 50 and the diameter of the cylindrical rod, a graph as shown in FIG. Here, the pressing force is the sum of the spring force load F and the self-weight of the cylinder rod in the case of a non-magnetic cylinder rod, and is the sum of the attraction force by the magnetic force in the case of a magnetic cylinder rod. In the figure, the curve shown by the solid line shows the case of a magnetic cylindrical rod, and the curve shown by the chain line shows the case of a non-magnetic cylindrical rod. As is clear from the figure, the amount of developer transported is a cylindrical rod.
It is determined by the balance between the force exerted on the cylindrical rod by the developer that slips into the wedge-shaped portion formed by the sleeve 50 and the sleeve 3, and the force in the sleeve direction of the cylindrical rod pressed by the spring or the spring and magnetic force. Indicates that. Further, in the case of the magnetic cylindrical rod, it is shown that the transport amount of the developer is more stable with respect to the fluctuation of the pressing force than the non-magnetic cylindrical rod. Non-magnetic SUS such as SUS310, Al, or polycarbonate is used as the material of the columnar rod 50, and SUS416 or SU is used as the magnetic columnar rod 50.
The results obtained by using a hard resin containing magnetic SUS such as S430, iron alloy, and magnetic powder are shown.

In this apparatus, the cylindrical rod is set to have a radius of curvature of 0.5 mm.
A cylindrical rod having a rigidity and magnetism of up to 15 mm, preferably 1 mm to 10 mm, and being set so that a pressing force of (1-15) gf / mm is applied, it is considerably A stable and close to the desired carrying amount was obtained. However, if the pressing force is too small, the regulation force of the developer amount is reduced and stable regulation cannot be performed. Further, it is not preferable because it is easily affected by external influence such as vibration of the developing device. Agglomerates of the developer are also passed through, and a uniform developer layer cannot be formed.

This is because when the pressing force is too high, the load on the developer becomes large, and the developer component is remarkably adhered to the vicinity of the regulation portion of the regulation body, and the regulation portion is clogged and the thin layer is formed. It cannot be formed.

By the way, the surface of the developing sleeve is generally subjected to precise grinding, but the surface condition is such that the projections and depressions of the irregularities are sharp as shown in FIG. 19, which causes the pressing as described above. Problems with regulations may appear.

In order to eliminate this, the surface of the developing sleeve is subjected to a spherical blasting process after grinding, or after the grinding process, a spherical blasting process after sandblasting and a process such as liquid honing are carried out to obtain the surface as shown in FIG. By rounding the sharp protrusions and removing burrs, unnecessary frictional force between the developing sleeve and the toner in the pressing portion is reduced, and the pressing member smoothly regulates the developer layer thickness. As a result, the above-mentioned non-uniform lumps of the developer in the control section and the clogging of the developer and dust, such as white streaks and uneven density, are eliminated and the developer becomes completely stable. In addition,
Rounding of convex parts on the surface after sandblasting, for example Sumitomo 3
If the surface lap processing is performed with a wrap film made of M or the like, the convex processing of the surface can be rounded, and the same effect as the above-described processing can be achieved. Glass beads or the like are suitable for the abrasive grains of the spherical blast.

The measured surface glossiness thus obtained was in the range of 2-1400% Gs (20 °).

From the above-mentioned various viewpoints, (1-15) gf / mm is appropriate for the selection of the pressing force, and (2-10) gf / mm is particularly preferable.
Is preferred. Further, in the case of the two-component developer using the magnetic spherical carrier as shown in Table 1, the above range is optimum as the pressing force. As a result, a stable image having a uniform density was obtained without any unevenness.

As a means for pressing the cylindrical rod in the sleeve direction, it is preferable to use a non-linear elastic member having a characteristic that the load (repulsive force) does not fluctuate with respect to the bending amount in the use range including before and after the use state. is there. FIG. 15 illustrates an example of a characteristic curve of a non-linear elastic member having such a characteristic. Shown are the characteristic curves for four types of PORON (trade name of INOAC, Inc.) with slightly different performances. When the bending amount is taken on the horizontal axis and the load is taken on the vertical axis, a gentle slope is stabilized in the operating range U. It indicates that the area.

By using a non-linear elastic member that presses in this range of use as a pressing member for the cylindrical rod, the fluctuations are absorbed even if there are errors in the component accuracy of the casing or holder and in the mounting conditions of the developing device. As the pressing force of the cylindrical rod against the sleeve is small, the layer thickness of the developer is kept uniform.

That is, it was confirmed that a very stable transport amount and a uniform thin layer can be formed as compared with a conventional developing device having a developer amount regulator and a conventional developing sleeve having a surface state.

A coating may be provided on a rod-shaped developer amount regulating member such as a cylindrical rod or the like, and a coating of polyurethane rubber or silicon rubber may be provided within a range where the effects of the present invention are not lost.

[0041]

Embodiments Based on the above results, an embodiment of a developing device to which the present invention is applied will be described with reference to FIG.

Embodiment 1 FIG. 3 is a sectional view of the main part of a developing device, in which 1 is an image carrier, 2 is a housing, 3 is a developing sleeve, 4 is a magnet roller, and 5 is a developer amount. Is a rigid and magnetic rod-like body (cylindrical rod), 15 is a holder for holding the cylindrical rod 5, and 6 is a spring material for allowing the developer to be conveyed by pressing the cylindrical rod 5 and the developing sleeve 3. The cylindrical rod 5 is pressed against the developing sleeve 3 with a constant load without the developer intervening. Reference numerals 7 and 8 are first and second stirring members, 9 is a supply roller, 10 is a scraper, and 11 is a stirring partition plate.

The toner replenished in the apparatus is sufficiently stirred and mixed with the carrier by the first stirring member 7 which rotates in the direction of the arrow and the second stirring member 8 which rotates so as to overlap each other in the opposite direction. The upper developer D is sent to the developing sleeve 3 via the supply roller 9.

The first stirring member 7 and the second stirring member 8
Is a screw-shaped member having a left-handed spiral angle that rotates in mutually opposite arrow directions, and the toner and the carrier conveyed to the inner side by the thrust of the second stirring member 8 are in the inner side direction in the drawing. The upper edge is gradually passed over the agitating partition plate 11 to move toward the first agitating member 7 side, and is conveyed to the front side of the drawing by its thrust, and is uniformly triboelectrically charged by the mixing action of the toner and the carrier in the meantime. The developer D is formed into a layered form on the peripheral surface of the developing sleeve 3 by the sponge-like supply roller 9 which rotates in the direction of the arrow.

The surface of the developing sleeve 3 is rounded as shown in FIG. 18 for the convex portion as described in the above section.

The developers used in the example shown in FIG. 3 are as shown in the table below.

[0047]

[Table 1]

In this apparatus, the cylindrical rod 5 is made of SUS having a rigidity and magnetism of 6 mm, and a load of (2-6) gf / mm is applied to the position where the cylindrical rod 5 faces the magnetic pole of the magnet roller 4. As a result, a uniform and evenly conveyed amount of about (7-9) mg / cm ² was obtained. As a result, a stable image having a uniform density was obtained. At that time, the magnetic flux density at the pressing position on the surface of the developing sleeve 3 was 600 gauss. FIG. 4 compares the amount of developer conveyed with the case where a non-magnetic cylindrical rod having a rigidity of 6φ mm is used instead of the magnetic cylindrical rod 5.

Regarding the transport amount when the rigid and magnetic cylindrical rod 5 was used, the relationship between the pressing force and the transport amount when the diameter was changed could be obtained as shown in FIG. A more appropriate transport amount can be selected. In particular, when the radius of curvature was 0.5 to 15 mm, a stable conveyance amount was obtained in which the force exerted by the developer D on the cylindrical rod 5 and the force of the cylindrical rod 5 toward the sleeve 3 were well balanced. More preferably, when the radius of curvature is 1 to 10 mm, the variation in the carry amount is very small regardless of the variation in the pressing force, and a uniform and thin developer layer thickness can be obtained.

Although non-magnetic stainless steel is used as the material of the developing sleeve 3 having rigidity, the same effect can be obtained by using materials having rigidity such as aluminum metal, hard resin, glass and ceramics. It was The surface roughness of the developing sleeve 3 was 3S. The same effect was obtained by using a surface roughness of (0.1-20) S. However, (0.3
~ 10) S is more preferable.

As described above, the developing sleeve 3
A uniform and stable thin developer layer in the range of 100 to 450 μm, preferably 150 to 400 μm is formed on the surface for a long period of time.

In this embodiment, the fixed magnet roller 4 is used.
This thin developer layer adhered on the peripheral surface of the developing sleeve 3 which rotates in the arrow direction (clockwise direction) on the outer side thereof and the latent image on the image carrier 1 which rotates in the arrow direction in the developing area 12. The image was developed in a non-contact manner at intervals to form a toner image.

FIG. 6 shows a state in which the developer layer formed in the example of FIG. 3 stands up near the developing portion. Assuming that the closest distance d between the developing sleeve body 3 and the image carrier 1 and the spike height of the developer are S, the condition of d> S is satisfied in the non-contact developing method.

During this non-contact development, a developing bias containing an AC component is applied to the developing sleeve 3 from a power source (not shown), and as a result, only the toner in the developer on the developing sleeve 3 is selectively applied to the surface of the latent image. It is transferred and attached.

The developer having consumed the toner component has a high carrier ratio, is conveyed by the developing sleeve 3, is separated and collected by the scraper 10, and is mixed again with the developer having a high toner ratio.

The specifications of the respective constituent members of the embodiment shown in FIG. 3 of the developing device of the present invention are as follows.

The developing sleeve 3 is made of a thin cylindrical stainless material having an outer diameter of 20 mmφ, and the outer peripheral surface is subjected to honing treatment to have a roughness of 3 μm and subjected to the above-mentioned surface treatment, and the convex portions are rounded as shown in FIG. The friction with the toner is reduced to 200 to 300 revolutions per minute, and in the present embodiment, it is rotated clockwise at 250 revolutions per minute. The developing sleeve 3 is required to have a small diameter because the developing device is downsized.
It is set to 15 to 30 mmφ. Also, various experiments were conducted on the rotation speed of the developing sleeve, but when the rotation speed is low, the supply amount of the developer is small and the image density when the latent image is developed is low. With respect to the developing sleeve having an outer diameter of 20 mm, the maximum image density increases linearly when the rotation speed is 0 to 200 rpm, and becomes saturated at 200 rpm or more. However, the maximum image density decreases when the environmental temperature is low, so it is necessary to set it with some margin.

As shown in FIG. 3, the magnet roller 4 is composed of magnets having 12 poles of equal magnetic poles in which N and S are alternately arranged at equal intervals, but a repulsive magnetic field is formed at a portion in contact with the scraper 10. However, in order to facilitate the peeling of the developer, one pole is omitted to make 11 poles, and the developer is contained in a fixed state in the developing sleeve 3. Note that the magnetic force of each magnet is preferably large in order to increase the carrier adhesion to the image carrier 1, but there is a manufacturing limit depending on the shape of the magnet roller, and the maximum magnetic flux in the direction normal to the circumferential surface of the developing sleeve 3. The density is maintained at 600 Gauss in this embodiment. Ferrite is used for the magnet roller 4. As shown in FIG. 6, the relationship between the developing sleeve 3 and the cylindrical rod 5 is a position facing the magnetic poles of the magnet roller 4, and the cylindrical rod 5 is pressed by the developing sleeve 3 and is attracted by the magnetized magnetic force. The pressing force is increased so that the developing sleeve 3 is brought into close contact with the developing sleeve 3 uniformly.

When the cylindrical bar 5 having rigidity and magnetism is used as the layer thickness regulating member in the above embodiment, white stripes due to developer agglomeration or toner sticking to the layer thickness regulating member in continuous copying, image quality. It was confirmed that excellent image quality with excellent reliability without deterioration was obtained. It was also confirmed that the above-mentioned effects were almost the same for the magnetic cylindrical rod and the non-magnetic cylindrical rod. The above-mentioned magnetic cylindrical rod may be magnetized and attracted to the developing sleeve 3 side, or may be magnetized and act to attract.

As can be seen from Example 1, the rigid and magnetic developer amount regulating member pressed against the developer carrying member determines the developer transport amount. An important factor is to use a rigid and magnetic cylindrical rod. As long as it is the curvature and the pressing force. Therefore, various other examples of the developer layer regulating member for giving the curvature and the pressing force are shown in FIGS. 7 to 13.

FIG. 7 shows an example in which the cylindrical bar 5 is held and pressed by the leaf spring 16, and FIGS. 8A and 8B further show the leaf spring 16.
This is an example in which the pressing force of can be partially adjusted by the adjusting screw 61. The leaf spring 16 'can be suitably implemented as an integral one in the axial direction of the cylindrical rod 5, a partial division by a slit, or a complete division.

FIG. 9 shows an embodiment in which a pressing force is applied by the coil spring 17. In this example, the semi-cylindrical rod 5a is formed by using only the vicinity of the pressing portion of the cylindrical rod 5. A plurality of coil springs 17 are arranged in the axial direction of the semi-cylindrical rod 5a so as to obtain a desired pressing force.

FIG. 10 shows an example in which the rubber-like elastic body 18 is compressed to obtain a pressing force. Not only the rubber-like elastic body but also a resin foam body can be used.

In FIG. 11, similarly to FIGS. 9 and 10, the cylindrical rod 5 is a semi-cylindrical rod 5a, and the compression spring 19 presses it.

In FIG. 12, the pressing portion has rigidity and magnetism, the radius of curvature is 6 mm, an edge portion is provided on the upstream side of the pressing portion, and the developer layer is regulated in advance to a predetermined thickness by the edge portion. The developer amount regulating member 5b. The pressing portion in FIGS. 11 and 12 is made of a material that is rigid and has a magnetic pole, and by pressing the developing sleeve 3 at a position corresponding to the magnetic pole or in the vicinity thereof, both can be used without any problem. is there.

In FIG. 13, the pressing portion has a two-layer structure, and the outer side of the cylindrical rod 5 is covered with a thin rubber material 5'such as urethane rubber or silicon rubber.

The thickness of the rubber material showing the pressing portion of the developer amount regulator is preferably 0.01 to 1 mm.

Embodiment 2 In this embodiment, the same developing device as shown in FIG. 3 is used, but the developing sleeve 3 is rotated in the same direction in the portion facing the image carrier 1. In this case, the cylindrical rod 5, which is the developer amount regulating body, is arranged at a position as shown in FIG. The developing sleeve 3 is made of non-magnetic stainless steel with a surface roughness of 1S (diameter 30φm
m), and the unevenness of the surface is rounded as shown in FIG. The magnet roller 4 has a sleeve surface magnetic flux density of 70.
An 8-pole type with 0 gauss was used. The cylindrical bar 5 has a diameter of 7 mm
The stainless steel SUS416 having rigidity and magnetism is disposed near the magnetic poles of the magnet roller 4, and is held by being sandwiched between the non-magnetic pressing leaf spring 6 and the holder 15. The parts of this embodiment which are not shown in FIG. 14 are configured in the same manner as the parts of the first embodiment described with reference to FIG. The columnar bar 5 is a device that is made of a columnar magnetic body, magnetizes the magnetic body by a magnetic field generated by the fixed magnet roller 4 in the developing sleeve 3, and obtains a pressing force by a magnetic attraction force. Since the cylindrical rod 5 presses the developing sleeve 3 with a magnetic attraction force that is evenly distributed in the longitudinal direction, a very good developer layer can be obtained.

Embodiment 3 FIG. 16 is a sectional view of the main part of a developing device showing a third embodiment, and parts having the same functions as those in FIG. 3 are indicated by the same part numbers. This embodiment is an example in which a non-linear elastic body is used as the pressing member.

The developing sleeve 3 is a cylinder made of a non-magnetic stainless material having an outer diameter of 20 mm rotating at 250 rpm in the direction of the arrow, and the surface thereof has a surface roughness of 3S by honing. Then, the surface convex portion is rounded in the same manner as described in the section of the action. Inside the developing sleeve 3, there are fixedly arranged magnet rollers 4 with 11 poles, and the maximum magnetic flux density is kept at 600 gauss on the surface of the developing sleeve.

At the position facing the magnetic pole of the magnet roller 4, the rigid and magnetic cylindrical rod 5 is pressed against the developing sleeve 3. The cylindrical rod 5 is made of magnetic SUS416,
A cylindrical rod with a diameter of 6 mm and excellent straightness, with a surface roughness of 0.
Grinded to 5S, no surface coating is provided.
The columnar bar 5 is restricted in lateral movement by a holder 35 attached to the housing 2, and is pressed by a non-linear elastic member 36 in the pressing direction. The non-linear elastic member used in this embodiment has a characteristic that the repulsive force is less likely to vary with respect to the amount of bending in the range of use, and PORON having the characteristic shown in FIG. 15 is used. In this embodiment, two non-linear elastic members 36 each having a plate thickness of 2 mm in thickness and 4 × 5 mm in length and width are bonded to the holder 35, and the columnar bar 5 is pressed. Figure 17
Is a perspective view showing a state in which the non-linear elastic member 36 is attached to the holder 35, and the entire length of the cylindrical rod 5 is pressed at two points divided into n: m: n = 2: 5: 2. 2-4 under such conditions
When the pressing force of gf / mm is set, the bending of the cylindrical rod 5 due to the pressing can be reduced, and the developer amount of 7 to 10 mg / cm ^{2 is} evenly distributed over the entire axial direction of the developing sleeve 3. The two-component developer regulated by No. 2 was transported. Further, in this embodiment, even if no adjusting portion for regulating the developer transport amount is provided, the above-mentioned good developing conditions are set.
Maintained.

As the non-linear elastic member 36, SORBOTHANE (manufactured by Sanshin Kosan Co., Ltd.), α-gel or the like is used in addition to the polyurethane foam PORON, and it is also possible to use a maltoplane or a non-linear spring.

As for the pressing method of the cylindrical rod 5 by the non-linear elastic member 36, the pressing method by the two-point support described in the above embodiment was effective in eliminating the bending of the cylindrical bar 5, but it was supported by a large number of points. It is also possible to press with continuous support. However, when such a pressing method is used, it is necessary to pay sufficient attention to the accuracy of parts and the parallelism of the holder 35.

In the above embodiment, the surface roughness of the developing sleeve 3 is 3S and the surface roughness of the cylindrical rod 5 is 0.5S. It is desirable that the surface roughness of the cylindrical rod 5 is close to a mirror surface of 0.5 or less, while the surface roughness of the developing sleeve 3 is required to be a rough surface in order to secure the required transport amount of the developer. However, the surface convex portion is required to be rounded as described above, and the surface roughness of the developing sleeve 3 is preferably larger (larger) than the surface roughness of the cylindrical rod 5. In addition, the surface roughness of the developing sleeve 3 is gradually smoothed and the amount of developer conveyed tends to be gradually decreased due to long-term use. In order to prevent this, it is desirable that the surface hardness of the developing sleeve 3 is high, and according to the experiment, it is desirable that the cylindrical rod 5 also has the same high hardness.

The embodiment has been described above.

In the embodiments of the present invention, a cylindrical rod is mainly used as the developer amount regulating member, but the present invention is not limited to these, and at least the pressing portion has rigidity and magnetism, and its radius of curvature is
Any rod-shaped body of 0.5 to 15 mm will do. However, the cylindrical rod does not necessarily have to be a magnetic substance, but a magnetic substance is more preferable.

Further, the developing conditions used in the present invention,
The developer components include the following. In the developing device of the present invention, the developing sleeve 3 for the image carrier 1
It is preferable that the distance, that is, the value of d in FIG. 6 is 0.3 mm to 0.7 mm, further 0.4 mm to 0.6 mm. Decreasing the distance between the developing sleeve 3 and the image carrier 1 enhances the electric field effect and adjusts the direction of the lines of electric force, so that blurring of the image during development does not occur. An average value of 0.5 mm
When the height of the developer is 200 μm-45 by selecting the multi-pole magnet roller as described above.
Since it is 0 μm, the gap d-S between the tip and the latent image surface is 0.05 mm ~
It is possible to maintain a value equivalent to 0.3 mm, that is, (0.1 to 0.6) × d.

The developer used in the present invention is preferably a two-component developer. It is considered that this is because the developer component adhering to the regulator is self-cleaning by the carrier, and a stable developer layer can be formed for a longer period than in the case of a one-component developer.
Examples of the two-component developer include a non-magnetic toner having a particle size of 1 to 20 μm (preferably 2 to 12 μm, more preferably 3 to 9 μm) and a particle size of a ferrite core coated with a resin material of 10
A developer composed of a carrier of 100 μm to 100 μm (preferably 30 to 60 μm) is preferably used in the developing device to which the present invention is applied, and the toner will be described below.

Thermoplastic resin (binder) (80 to 90) wt% Example: polystyrene, styrene acrylic polymer, polyester, polyvinyl butyral, epoxy resin, polyamide resin, polyethylene, ethylene vinyl acetate copolymer, or the like Mixture of pigment (coloring agent) 0 to 15 wt% Example: Black: Carbon black Yellow: Benzidine derivative Magenta: Rhodamine B lake, Carmine 6B, etc. Cyan: Copper phthalocyanine, sulfonamide derivative, etc. Charge control agent 0-5 wt% Plus toner: Nigrosine-based electron-donating dyes, alkoxylated amines, alkylamides, chelates, pigments, 4
Mineral toner, etc. Minus toner: electron-accepting organic complex, chlorinated paraffin, chlorinated polyester, polyester with excess acid groups,
Chlorinated copper phthalocyanine, etc. Fluidizing agent Example: Colloidal silica, hydrophobic silica, silicon varnish, metal soap, nonionic surfactant, etc. Cleaning agent (prevents toner filming on the photoreceptor) Example: fatty acid metal salt, Silicon oxide having an organic group on the surface,
Fluorine-based surfactants and other fillers (improving image surface gloss and reducing raw material costs) Example: In addition to these materials such as calcium carbonate, clay, talc, and pigments, to prevent fogging and toner scattering on the image surface, A small amount of magnetic powder may be contained. As such magnetic powder, triiron tetraoxide having a particle size of 0.1 μm to 1 μm, γ-ferric oxide, chromium dioxide, nickel ferrite, iron alloy powder, etc. are used, 0.1-5) wt% In order to maintain a more vivid color, it is desirable that the amount be 1 wt% or less.

As the resin suitable for the pressure fixing toner which is plastically deformed by a force of about 20 kg / cm and fixed on the paper,
Adhesive resins such as wax, polyolefins, ethylene vinyl acetate copolymer, polyurethane and rubber are used.

On the other hand, the surface potential on the image carrier 1 side is -600V,
The exposed portion potential is 0 to -100V, and the developing sleeve 3 has a DC bias of -500V, an AC bias of 700V (rms),
When development was attempted under the condition that a voltage of frequency 4 kHz was applied, it was confirmed that a high-quality toner image with extremely high resolution and gradation was obtained. The developer to be used may be a two-component system or a one-component system as shown in Table 1, and the particle size of the toner, the softening point and the glass transition point may be selected from a wide range.

[0082]

As described above, the developing device of the present invention has rigidity, has the same rigidity and magnetic property as the developer carrying member (developer sleeve) whose surface is roughened and whose convex portion is rounded. Since the developer layer forming portion is configured by pressing the developer amount regulating body formed of a member having rigidity with a small radius of curvature, it is possible to change the rotation speed and the pressing position of the developer carrier. It is not affected, and in particular, the stability of the carry amount against the fluctuation of the pressing force can be obtained, and the developer layer having a stable thickness can be obtained. Therefore, as compared with the conventional one, a uniform and stable developer layer can be obtained under a low load.

Further, it is difficult to cause clogging due to foreign matters, and the pulverizability of aggregated toner and developer lumps is excellent, and white lines are less likely to appear on the image. Further, the fluctuation of the developer amount after the regulation due to the change of the pressing force at the pressing portion of the developer amount regulating member with respect to the developer carrying member is extremely small, and a developing device having excellent developability becomes possible. It is possible to provide a high-quality image that prevents the developer component from adhering to the regulation member in the above step, and thus can stably form a thin layer having no unevenness and does not cause uneven density or decrease in density.

Since the developing device of the present invention does not deform the developer carrying member (developing sleeve) or the regulating member during long-term use and has little change in the attraction force due to the magnetic force, it is extremely durable as the regulating device. Furthermore, the mounting accuracy is relatively large even during mass production, and it is highly practical.

Further, since the developer control area is small, an adverse effect due to unnecessary triboelectric charging with the developer is unlikely to occur and a good image can be obtained.

In addition, even when the regulation member is replaced, the attachment is easy and the maintainability is high.

Further, when the non-linear elastic member is used as the pressing member for the cylindrical rod, it absorbs an error in accuracy of parts of the casing and the holder and a variation at the time of assembling, so that it is always stable even if the adjusting portion is not provided. A developing device is provided in which a good amount of developer can be conveyed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an experiment that is the basis of the present invention.

FIG. 2 is a diagram showing the relationship between the presence / absence of magnetism, the curvature at the pressing portion, the pressing force, and the carry amount, obtained by the experiment of FIG.

FIG. 3 is a configuration diagram showing a first embodiment.

FIG. 4 is a relational graph obtained by Yuki.

FIG. 5 is a relational graph obtained by the author.

FIG. 6 is an explanatory diagram of development between an image carrier and a developing sleeve.

FIG. 7 is a main part diagram showing another application example of the first embodiment.

FIG. 8 is an explanatory diagram of a first application example of a developer layer restriction member.

FIG. 9 is an explanatory diagram of a second application example of the developer layer restriction member.

FIG. 10 is an explanatory diagram of a third application example of the developer layer restriction member.

FIG. 11 is an explanatory diagram of a fourth application example of the developer layer restriction member.

FIG. 12 is an explanatory diagram of a fifth application example of the developer layer restriction member.

FIG. 13 is an explanatory diagram of a sixth application example of the developer layer restriction member.

FIG. 14 is a configuration diagram showing a second embodiment.

FIG. 15 is a graph showing the relationship between deflection and load for an example of a non-linear elastic body.

FIG. 16 is a configuration diagram showing a third embodiment.

FIG. 17 is a perspective view of a main part thereof.

FIG. 18 is a surface state diagram of the developing sleeve surface in the present invention.

FIG. 19 is a surface state diagram of a conventional developing sleeve surface.

[Explanation of symbols]

 1 image carrier 3 developing sleeve 4 magnet roller 5 bar (cylindrical rod) 6 spring material 15,35 holder 36 non-linear elastic member

Claims (5)

[Claims] 1. A fixed magnet body, a developer carrying body which has the magnet body inside, and has a rigidity for carrying a developer on the surface, and the developer carrying body facing the magnet body. In a developing device having a rod-shaped developer amount regulating body that is pressed by the developer supporting body and regulates the amount of the developer carried on the developer carrying body, the developer amount regulating body is a pressing portion with the developer carrying body. Is a rigid material, and the pressing part has a radius of curvature of 0.5 to 15 m.
m, the developer carrying member is subjected to an unevenness forming treatment on the surface carrying the developer, and the glossiness of the surface is 2 to 1400% Gs (20
The developing device is characterized in that 2. The developing device according to claim 1, wherein the unevenness forming process is a spherical grain blasting process. 3. The developing device according to claim 1, wherein the unevenness forming process is a spherical grain blasting process after an irregular grain blasting process. 4. The developing device according to claim 1, wherein the unevenness forming process is a wrapping process using a wrap film after the irregular grain blasting process. 5. The developing device according to claim 1, wherein the pressing portion has magnetism.