JPH03209487A - Developing device - Google Patents

Abstract

PURPOSE:To stably form the uniform thickness of one component developer on a developer carrier by forming a part pressed on the developer carrier of a regulating body with a material having rigidity and magnetism, and making the radius of curvature on the pressing part 0.5-15mm. CONSTITUTION:Important factors for which a developer quantity regulating member having the rigidity pressed on the developer carrier and magnetism, determines the carrying quantity of the developer, are its curvature and pressing power as long as a columnar rod having the rigidity and magnetism, but the columnar rod 5 having the rigidity of 0.5-15mm the radius of curvature and magnetism is used to obtain a stable and desired carrying quantity regardless of the fluctuation of the pressing power when this device is operated. The relation between a developing sleeve 3 and the columnar rod 5 is acted so that the columnar rod 5 is pressed on the developing sleeve 3, attracted by magnetic force magnetically induced to increase the pressing power, and uniformly adheres to the developing sleeve 3, at a position opposed to the magnetic pole of a magnet body 4. Thus, a developer layer having a stable thickness can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device applied to developing a latent image on an image forming body, particularly an image forming body used in an electrophotographic image forming apparatus. be.

[Background of the invention]

! In an electrophotographic image forming apparatus using a two-component developer, in order to obtain a good image, the layer thickness of the developer on the developer carrier (also referred to as a developing sleeve) is made thin. Moreover, it is necessary to make it uniform.

Conventionally, the layer thickness has been regulated by a fixed regulation plate that has been used for a long time, but there are limits to the mechanical attachment precision between the developer carrier and the fixed regulation plate, and the lower limit for the layer thickness is about 0.3 mm. It becomes. Furthermore, it was difficult to obtain a uniform and even thin layer with this method. However, various developer layer thickness regulating devices other than fixed regulating plates have been devised for the purpose of obtaining a uniform thin layer. For example, (a) the developer layer forming device described in JP-A-54-43038 uses a developer layer formed by a plate-shaped elastic body having a free end on one side on a developer carrier when using an l-component toner. (b) The developer layer forming device described in Japanese Unexamined Patent Publication No. 54-51848 is a plate-shaped elastic body in which a metal spring and a soft elastic body are superposed. The layer thickness of the l-component developer is regulated by pressing the plate-shaped abdomen of the soft elastic body against the developer carrier.

(c) Japanese Patent Publication No. 59-126567, 59-12987
The developer layer forming device described in Publication No. 9, etc. is a developing device that also uses an l-component developer, and presses a developer carrier and an elastic roller that rotates intermittently or continuously to form a nip between the two. This controls the layer thickness of the developer.

(d) The developer layer forming device described in Japanese Patent Publication No. 60-12627 is a developing device using an l-component developer, in which a rotating roller is brought into contact with a developer carrier made of an elastic material to control the layer thickness of the developer. It is something that is regulated.

(e) JP-A No. 62-191868 and JP-A No. 62-62 as improved versions for use in two-component developers.
Japanese Patent No. 191869 and the like discloses a technical means for forming a thin developer layer on a developing sleeve suitable for non-contact development.

This directs the tip of the elastic plate supported by the support member toward the upstream direction of the movement of the developer on the developing sleeve, and presses the elastic plate onto the developing sleeve, thereby causing the developer to adhere to the developing sleeve. By regulating the layer thickness of the developer containing the magnetic carrier and toner to be transported, the developer layer thickness can be easily set to a thinner layer with higher precision than conventional regulating means.

(f) Also, in the developing device which similarly uses a two-component developer and is described in JP-A-61-189582 and JP-A-62-75563, a solid plate-like layer thickness regulating member is provided and a magnetic material is attached to the back surface of the developing device. Disclosed is a method in which the layer thickness is regulated by indirectly pressing the abdomen or bent edge of the regulating plate by the attractive force of a fixed magnet provided in the developer carrier. There is.

[Problem that the invention seeks to solve]

Each of the conventionally proposed developer layer forming apparatuses has the following drawbacks. (a), (
b) Since both devices utilize the pressing force generated by bending the layer thickness regulating member made of an elastic body, the pressing force is subject to fluctuations such as the rotational speed of the developer carrier, the pressing position, and the developer layer thickness. It is easy to vibrate, and since no means have been taken to suppress the vibration, it resonates with the vibrations generated within the image forming device and vibrates, resulting in a uniform thickness. There is a problem that it becomes difficult to obtain a developer layer of In addition, especially in the device (b), this tendency is noticeable because the pressure is applied using a soft elastic body.
Furthermore, the geometrical shape of the nip (the protrusion at the contact portion) is easily subject to perturbations due to variations in the rotational speed of the developer carrier, the pressure contact position, the developer layer thickness, etc., and the area of the nip changes. Therefore, a problem arises in that the thickness of the developer layer tends to be uneven.

In addition to these inconveniences, when one or both of the nip members are made of a soft elastic material, there are other inconveniences such as clogging of the nip with developer and fluctuations over time due to wear of the (soft) elastic material. These disadvantages are particularly likely to occur in the case of a developer containing a hard substance such as a magnetic material or a fluidizing agent. In addition, the device (c) can obtain a more stable and uniform thin layer than the device (a), but because it uses a layer thickness regulating means using a rotating body, it has no ability to loosen or eliminate agglomerated particles of the developer. In other cases, the performance is poor, and a phenomenon occurs in which agglomerated particles are caught in the nip and pass through as the rotating body rotates, and satisfactory performance cannot always be obtained even with intermittent rotation. First, it causes image stains, black spots, etc., and deteriorates the image quality. Furthermore, in order to balance the pressure, the rotation mechanism, pressure contact mechanism, etc. have become complicated.

In addition, in any of the devices (a) to (d), the pressing area of the layer thickness regulating member is relatively large and the amount of developer fed into the nip section fluctuates from time to time in a normal developing device. There is a drawback that the thickness of the developer layer changes from moment to moment, reflecting the fluctuations.

(C) and (d) are techniques suitable for non-magnetic l-component developers in which the developer carrier has elasticity and a developer layer thickness regulating member is pressed against it to form a thin layer of developer. However, the developer carrying member may be permanently deformed, and the elastic modulus of the developer layer thickness regulating member tends to change over a long period of use, making it impossible to form a stable layer.

Even in (e) developed for two components, sufficient properties cannot be maintained during long-term use.

Furthermore, in (a), (b), (e) and Cf), an elastic developer layer thickness regulating plate is pressed against a rigid developer carrier (metal sleeve) to form a thin layer,
During long-term use, the elastic plate tends to change its elastic modulus and undergo permanent deformation, and has the drawback of short durability as a layer thickness regulating member.

Moreover, if the position of the elastic plate changes slightly when installing the elastic plate, the amount of play at the tip and the pressing force will change, making it difficult to regulate the layer thickness stably. For this reason, it also has a serious drawback in that mounting accuracy is extremely strict during mass production.

Particularly in (f), although the effect of disentangling toner agglomeration by the magnets arranged on the back side of the developer layer thickness regulating member and inside the developer carrier is somewhat effective, Since the attraction force is used, the attraction force decreases rapidly as the distance between both magnets increases, and the pressure tends to fluctuate due to distance changes.The pressing effect on the developer layer is not stable and uniform, and the toner Alternatively, there are disadvantages in that developer aggregates may pass through or, conversely, a constant layer thickness may not be obtained, which may have negative effects such as blurring and white streaks on image quality.

The present invention solves these problems and stably forms a good image by uniformizing the layer thickness of a one-component developer on a developer carrier, thereby eliminating agglomerated developer and toner. It is an object of the present invention to provide a developing device that can prevent particles from moving to a developing area.

[Means for solving problems]

The above object is to provide a developer carrier having rigidity that supports an l-component developer, a magnetic body or a magnet body fixed inside the developer carrier, and a magnetic body or a magnet body that faces the magnetic body or magnet body to hold the developer. It has a rod-shaped developer amount regulating body that is pressed against the carrier and regulates the amount of developer carried on the developer carrying body, and the pressing part of the regulating body with the developer carrying body is rigid and magnetic. The material has a radius of curvature of 0.5 to 0.5 at the pressing part.
This is achieved by a developing device characterized by 15 ohm.

[Description of means for solving the problem] The present invention forms a stable thin layer by pressing a similarly rigid rod-shaped magnetic member as a developer amount regulator onto a rigid developer carrier. I was able to do that.

In the present invention, having rigidity refers to having a large rigidity, that is, having a rigidity of 10'kg/cm2 or more, specifically (0.8 to 1.6)XIO
Contains various magnetic metals including iron and its alloys, and magnetic powder, which has a rigidity of about 1.0 to 10 x 10'kg/co+''. A hard resin having the following formula can also be used as a developer amount regulator in the present invention. Iron and iron alloys plated with chromium or the like are also used.

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

The present inventors conducted the following experiment.

Using an experimental apparatus as shown in FIG. 1, layers were formed using magnetic and non-magnetic cylindrical rods 50. That is, a magnet roller 4 having a plurality of magnetic poles was fixed, and the developing sleeve 3 was rotated in the direction of the arrow on the outside thereof. A cylindrical rod 50 was pressed against this developing sleeve 3 using a spring force. The pressing position of the cylindrical rod 50 was set to be 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. 2 was obtained regarding the amount of conveyance. In the case of a non-magnetic cylindrical rod, the pressing force is the sum of the spring clamp load F and the cylindrical rod's own weight, and in the case of a magnetic cylindrical rod, it is the sum of the attractive force due to magnetic force. In the figure, the curve shown by a solid line shows the case of a magnetic cylindrical rod, and the curve shown by a chain line shows the case of a non-magnetic cylindrical rod. As is clear from the figure, the amount of developer conveyed is determined by the force exerted on the cylindrical rod by the developer that enters the wedge-shaped portion formed by the cylindrical rod 50 and the sleeve 3, and the force exerted on the cylindrical rod by the spring or by the spring and magnetic force. This shows that it is determined by the balance with the force of the rod in the direction of the sleeve. Furthermore, in the case of a magnetic cylindrical rod, compared to a non-magnetic cylindrical rod, the amount of developer conveyed is stable against fluctuations in pressing force. Cylindrical rod 5
0 material, non-magnetic SUS such as SUS 310
, AQ, and polycarbonate, and as the magnetic cylindrical rod 50, magnetic SUS such as SUS 416 and SUS 430, iron alloy, and hard resin containing magnetic powder were used. There is.

In this device, the cylindrical rod has a radius of curvature of 0.5 mm-15
IllI is preferably a rigid and magnetic cylindrical rod of IllII to 10 mm, (1=15) gf/+u
When the setting was made so that a pressing force of a was applied, a stable desired conveyance amount was obtained regardless of fluctuations in the pressing force during operation of the device. If the pressing force is too small, the ability to regulate the amount of developer decreases and stable regulation cannot be achieved. Further, it is undesirable because it is easily affected by external influences such as vibrations of the developing device. The agglomerates of the current Ill are also passed through, making it impossible to form a uniform developer layer.

If the pressing force is too high, the load on the developer will increase, and developer components will become noticeable near the regulating part of the regulating body. Not only will it not be possible to withstand long-term use, but paper dust, etc. Even small lumps of rubber or developer can get stuck in the regulating section, making white streaks more likely to occur.

The pressing force is selected from the above various viewpoints (1-15)gf
/++i is appropriate, especially (2 to 10) gf/no+
is preferred. Further, in the case of the l-component developer shown in Table 1, the above range is optimal for the pressing force.

As a result, images with uniform density and stable density can be obtained.I
child .

As the means for pressing the cylindrical rod toward the sleeve, it is preferable to use a nonlinear elastic member that has a characteristic that the load (repulsion force) does not change much with respect to the amount of deflection in the range of use including before and after the use state. An example of the characteristic curve of a nonlinear elastic member having such characteristics is shown in Figure 7.
It is a diagram. The illustration shows four types of F with slightly different performance.
This is a characteristic curve for ORON (product name of NoAC Company), where the horizontal axis represents the amount of deflection and the vertical axis represents the load, indicating the usage range U.
This indicates a stable region with a gentle slope.

By using a non-linear elastic member that presses within this range of use as the pressing material for the cylindrical rod, even if there are errors in the precision of the parts of the casing or holder or variations in the assembly of the developing device depending on the condition, the fluctuations can be absorbed and the cylindrical rod can be pressed. There is little variation in the pressing force of the rod against the sleeve, and the thickness of the developer layer is kept uniform.

That is, it was confirmed that a very stable conveyance amount and a uniform thin layer could be formed compared to the conventional developing device having a developer amount regulator.

Note that a thin film for controlling the charge of the developer may be provided on a rod-shaped developer amount regulating member such as a cylindrical rod within a range that does not impair the effects of the present invention.

〔Example〕

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

FIG. 3 shows a cross section of the main parts of a developing device using a non-magnetic one-component developer, where l is an image carrier, 2 is a housing, 3 is a non-magnetic developing sleeve rotating in the direction of the arrow, 4
5 is a fixedly positioned magnetic body, 5 is a rigid and magnetic rod-shaped body (cylindrical rod) that regulates the amount of developer, and 7 is a cylindrical rod 5
A holder 6 that holds the cylindrical rod 5 presses the cylindrical rod 5 against the developing sleeve 3 and is made of elastic rubber such as Ripolon, and is used to transport the developer.
It is pressed with a constant load without the presence of developer. Reference numeral 9 denotes a supply roller made of sponge or the like, which rotates in the direction of the arrow.

The non-magnetic one-component developer replenished into the housing 2 is
It adheres to the rotating developing sleeve 3 and is pressed by the cylindrical rod 5 to form a thin layer, and is carried along with the rotating developing sleeve 3 to the developing area 12 facing the image carrier 1 where development is performed. be exposed. The residual developer remains attached to the developing sleeve 3 and is carried to a place where it is in sliding contact with the supply roller 9, and is separated from the developing sleeve 3, and new developer adheres to the developing sleeve 3 in its place.

The developing sleeve 3 is a non-magnetic rigid metal roller,
Non-magnetic stainless steel, aluminum, or the like may be used, and the surface may be finished with a smooth surface; however, a smooth surface tends to reduce the amount of toner conveyed. In order to develop the latent image on the image carrier L, it is necessary to supply a much larger amount of toner than the amount of toner required for development in the development area 12, so the rotation speed of the development sleeve 3 is increased. By increasing the linear velocity ratio of the developing sleeve 3 to the image carrier 1, the developed density can be increased. However, it is preferable that the surface of the developing sleeve 3 is rough rather than smooth to increase the amount of toner conveyed, so that the thin layer of toner formed by the cylindrical rod 5 is adhered to and conveyed to the developing area 12 as it is. The surface roughness of the developing sleeve 3 is uneven and is 0.1 p ra to 20
p m, preferably 0.5/7 va-5 p tn, and the pitch of the unevenness is also 0.5 p - 50 μm, preferably 2 μm = 10 μm. However, the amount of toner conveyed depends not only on the surface roughness of the developing sleeve 3, but also on the particle size distribution, fluidity, and charge amount (Q/m) of the toner particles.
) etc. Further, a coating layer suitable for toner transport may be provided on the surface of the developing sleeve 3. In this case, it is necessary to select a material that imparts a triboelectric charge to the toner.
The coating is applied to a thickness of ~500 μm, and the surface roughness of the coating material at this time is also appropriately selected.

The developer used in the example shown in Figure 3 is as shown in the table below.

Table 1 In this device, the cylindrical rod 5 is made of 6-mm rigid and magnetic SUS, and a load of (2 to 6) gf/■■ is applied to the cylindrical rod 5 at a position facing the magnetic pole of the magnet body 4. In this way, it is uniform and even and almost (0.7 to 0.9
) +H/c+++' transport amount was obtained. As a result, an image with stable density and no unevenness was obtained.

At this time, the magnetic flux density due to the magnet body 4 at the pressed position on the surface of the developing sleeve 3 was 600 Gauss. The magnet density of the fixedly positioned magnet body 4 on the surface of the developing sleeve 3 in the normal direction of the sleeve is 350 Gauss to 1400 G.
auss, preferably 500" and 1000 gauss. Instead of the magnetic cylindrical rod 5, a non-magnetic 6-
FIG. 4 shows a comparison of the amount of developer conveyed when a cylindrical rod having a rigidity of 1 is used.

Regarding the amount of conveyance when using the rigid and magnetic cylindrical rod 5, we were able to obtain the relationship between the pressing force and the amount of conveyance when the radius was changed as shown in Fig. You can choose the transport amount. In particular, the radius of curvature is 0.
In the case of 5 to 15 m+s, a stable conveyance amount was obtained in which the force exerted by the developer on the cylindrical rod 5 and the force of the cylindrical rod 5 in the direction of the sleeve 3 were well balanced. More preferably, when the radius of curvature is I to lOa+m, the variation in the amount of conveyance is very small regardless of the variation in the pressing force, and a uniform and thin developer layer thickness can be obtained.

In this embodiment, the fixed magnet body 4 and its outside are moved in the direction of the arrow (
This thin developer layer attached to the circumferential surface of the developing sleeve 3 rotating in the clockwise direction separates the latent image on the image carrier l rotating in the direction of the arrow in the developing area 12 without contacting it. The toner image was formed by developing the toner image.

It is also possible to carry out contact development, but in 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 the toner on the image sleeve 3 is formed selectively into the latent image. It migrates and adheres to the surface.

Here, the relative position between the developing sleeve 3 and the cylindrical rod 5 is the third
As shown in the figure, the cylindrical rod 5 is pressed against the developing sleeve 3 at a position facing the magnetic pole of the magnet body 4, and is attracted by the induced magnetic force, increasing the pressing force and coming into close contact with the developing sleeve 3 uniformly. It's working like that.

In the above embodiment, when the rigid and magnetic cylindrical rod 5 is used as the layer thickness regulating member, there may be problems such as white streaks due to developer aggregation, toner sticking to the layer thickness regulating member during continuous copying, and deterioration of image quality. It was confirmed that this method has excellent reliability and provides good image quality. It has also been confirmed that the above effect is better for magnetic cylindrical rods than for non-magnetic cylindrical rods. Note that the magnetic cylindrical rod described above may be one that is magnetized and attracted to the developing sleeve 3 side, or may be one that is magnetized and acts to be attracted.

FIG. 6(a) shows a main part of the thin layer forming part in FIG. The cylindrical rod 5 is magnetized.

Further, FIG. 6(b) shows the opposite condition/state, in which the rod-shaped body 115 is a magnetic body, and the magnetic body 114 fixedly located inside the developing sleeve 3 is moved by the rod-shaped body 115. It is magnetized. The developing device of the present invention forms a thin layer of toner in either of the two embodiments shown in FIGS. 6(a) and 6(b). In the embodiment shown in FIG. 3, the specifications of each component are as follows.

The developing sleeve 3 is made of a thin cylindrical stainless steel material with an outer diameter of 20m5+-, the outer circumferential surface of which has been honed to a roughness of 3 μm, and rotates counterclockwise at 50 to 200 revolutions per minute, in this example 90 revolutions per minute. That is, the rotation direction of the developing sleeve 3 is rotated in the same direction at the portion facing the image carrier l. The diameter of the developing sleeve 3 is set to 15 to 30 mm, although a small diameter sleeve is required due to the miniaturization of the developing device, due to limitations on the magnetic force of the built-in magnet. We also conducted various experiments regarding the rotation speed of the developing sleeve, and found that when the rotation speed is low, the amount of developer supplied is small and the image density when the latent image is developed is also low. Regarding a developing sleeve with an outer diameter of 20 mm, the maximum image density increases linearly when the rotation speed is from 0 to 200 rotations per minute, and reaches a saturated state when the rotation speed is 200 rotations per minute or more. However, when the environmental temperature is low, the maximum image density decreases, so it is necessary to set it with some margin.

Next, to explain another embodiment with different specifications, the developing sleeve 3 is a cylinder made of non-magnetic stainless steel with an outer diameter of 201 mm that rotates at 9 Orpm in the direction of the arrow, and the surface is honed for 3 seconds. The surface is rough. There is a magnet body 4 fixedly located inside the developing sleeve 3, and the maximum magnetic flux density is maintained at 900 Gauss on the surface of the developing sleeve.

A rigid and magnetic cylindrical rod 5 is pressed against the developing sleeve 3 at a position facing the magnetic pole of the magnet body 4 . The cylindrical rod 5 is made of magnetic SUS 416 and has a diameter of 6-alI.
Excellent straightness of l; cylindrical rod, surface roughness is 0.5
S is grinded and has no surface coating. The cylindrical rod 5 is restricted from moving in any direction by a holder 7 attached to the housing 2, and is pressed in the suppressing direction by a nonlinear elastic member 36. The nonlinear elastic member used in this embodiment has a characteristic that the repulsion force varies little with respect to the amount of deflection within the range of use, and FORON having the characteristics shown in FIG. 7 is used. In this example, the thickness is 2 m.
Two nonlinear elastic members 3 each having a plate shape of 4 x 51 m in length and width.
6 was adhered and disposed on the holder 7, and the cylindrical rod 5 was pressed. FIG. 8 shows how the nonlinear elastic member 36 is attached to the holder 7, and the total length of the cylindrical rod 5 is expressed as n:m:n=
Pressure is applied at two points divided at a ratio of 2:5:2. When the pressure force of 2 to 4 gf/+m- is set to be applied under these conditions, it is possible to reduce the deflection of the cylindrical rod 5 due to the pressure, and it is possible to reduce the deflection of the cylindrical rod 5 evenly over the entire axial direction of the developing sleeve 3. .7~1. Toner was transported with the amount of developer regulated to 0mg/cm''.

Further, in this example, the above-mentioned favorable developing conditions were set and maintained even without providing any adjustment point for regulating the amount of developer conveyed.

As the nonlinear elastic member 36, in addition to the urethane foam FORON, 5ORBOTHANE (manufactured by Nishin Kosan Co., Ltd.), a-gel, etc. are used, and it is also possible to use Moltoprene, a nonlinear spring, etc.

Furthermore, the method of pressing the cylindrical rod 5 by the nonlinear elastic member 36 was also described in the above embodiment. It is also possible to press it by supporting it. However, when such a pressing method is used, sufficient attention must be paid to the precision and parallelism of the parts of the holder 7.

In the above embodiment, the surface roughness of the developing sleeve 3 is 3s.
The surface roughness of one cylindrical rod 5 was set to 0.5S.

The surface roughness of the cylindrical rod 5 is preferably 0.5 or less and is close to a mirror surface, while the surface roughness of the block image sleeve 3 needs to be rough in order to ensure the required amount of developer to be conveyed. It is preferable that the surface roughness of the developing sleeve 3 is rougher (larger) than the surface roughness of the cylindrical rod 5. Furthermore, after long-term use, the surface roughness of the developing sleeve 3 tends to become smoother and the amount of developer conveyed gradually decreases.

In order to prevent this, it is desirable that the surface hardness of the developing sleeve 3 is high, and according to experiments, it is desirable that the cylindrical rod 5 also have a similar high hardness.

FIG. 9 is a configuration diagram showing a developing device according to another embodiment. This embodiment uses a developing device similar to the developing device shown in FIG. Development area 1
In the example in which the direction is reversed in 2), 10 is a scraper that scrapes the toner from the developing sleeve 3, and 11 is a stirring member that stirs old and new toner. The developing sleeve 3 is made of non-magnetic stainless steel (diameter 30 lmm) with a surface roughness Is, and the fixedly positioned magnet 4 has a sleeve surface magnetic flux density of 450 Gauss. The cylindrical rod 5 has a diameter of 7 d+sm and is made of rigid and magnetic stainless steel SUS 416, and is disposed near the magnetic pole of the magnet body 4 and held between a non-magnetic pressing leaf spring 6 and a holder 7. .

FIG. 8 shows an embodiment of the method for supporting the cylindrical rod 5, which is the developer amount regulating member. The important factors that determine this are its curvature and pressing force as long as a rigid and magnetic cylindrical rod is used. Therefore, examples of various other developer layer regulating members for providing this curvature and pressing force are shown in FIGS. 1O to 16. In all of the embodiments shown here, the cylindrical rod 5 is located below the developing sleeve 3, but the relationship may be reversed.

FIG. 1O shows an example in which a magnetic cylindrical rod 5 is held and pressed by a leaf spring 16, and FIGS. 11(a) and (b) further show that the pressing force of the leaf spring 16 is partially adjusted by an adjustment screw 61. This is an example of how it can be done. The plate spring 16' can be suitably implemented as one that is integrated in the axial direction of the magnetic cylindrical rod 5, one that is partially divided by a slit, or one that is completely divided.

FIG. 12 shows an embodiment in which a pressing force is applied by a coil spring 17. In this example, a semicircular branch rod 5a is used that uses only the vicinity of the pressing part of the cylindrical rod 5 made of magnetic material. A plurality of coil springs 17 are arranged in the axial direction of the semicircular branch rod 5a to obtain a desired pressing force.

FIG. 13 shows an example in which a pressing force is obtained by compressing the rubber-like elastic body 18. Not only rubber-like elastic bodies but also resin foams can be used in the same manner.

In FIG. 14, as in FIGS. 12 and 13, the cylindrical rod 5 is a semi-cylindrical column 5a, and is pressed by a compression spring 19.

Fig. 15 shows a rod-shaped developer whose pressing part is rigid and magnetic and has a radius of curvature of 61110, an edge part is provided on the upstream side of the pressing part, and the edge part regulates the developer layer to a predetermined thickness in advance. This is a quantity regulator 5b. The pressing portion in FIGS. 14 and 15 is made of a material that is rigid and has a magnetic pole, and is configured to press at a position corresponding to the magnet 4 on the developing sleeve 3 or in the vicinity thereof, so there is no problem in either case. It can be used without any problems.

In FIG. 16, the pressing part has a two-layer structure, and the outside of the cylindrical rod 5 is covered with a thin rubber material 5' such as urethane rubber or silicone rubber. Here, the thickness of the rubber material exposing the pressing portion of the developer amount regulator is preferably 0.01 to 1 am.

FIG. 6(a) shows an embodiment in which the magnet body 4 is fixed inside the developing sleeve 3, and FIGS. 17 to 20 show the magnet body 4 having the configuration shown in FIG. 6(a). This shows a modified example of . 14 and 24 in FIGS. 17 and 18 are modified examples in which magnet bodies each having a plurality of repelling magnetic poles of the same polarity are fixed.

By providing such a magnet, the width of the magnet wire inside the developing sleeve 3 becomes wider, and the area for regulating the amount of toner is softly expanded, so that even if the position where the magnetic cylindrical rod 5 comes into contact deviates from the basic position, Its influence is small.

FIG. 19 shows a modification in which two magnet bodies 34A and 34B are fixedly arranged close to each other, and a magnetic cylindrical rod 5 is pressed against the developing sleeve 3 while facing between the magnet bodies.

FIG. 20 shows that at least two fixed magnet bodies 44A and 44B are provided inside the developing sleeve 3, and a magnetic cylindrical rod 45A is brought into contact with the developing sleeve 3 in opposition to the magnet body 44^. A cylindrical rod 45B made of magnetic material is brought into contact with the developing sleeve 3 facing the magnet body 44B to form a second regulating section, and the first regulating section and the second regulating section cooperate to thin the toner. This is a modification in which layers are formed. Here, the amount of toner that cannot be regulated by the first regulating part is adjusted to an appropriate amount by the second regulating part. are made to be different.

In FIG. 6(b), a magnetic body 114 is provided inside the developing sleeve 3, and a bar-shaped body 115, which is a magnet, is placed in contact with the developing sleeve 3. FIG. 22 shows this modification.

In FIG. 21, a magnet body 114 is fixed inside the developing sleeve 3, a rod-shaped body 125 with a plurality of repelling magnetic poles is opposed to the developing sleeve 3, and a sponge-like elastic body 106
to bring the rod-shaped body 125 into contact with the developing sleeve 3,
This is a modification in which a thin layer of toner is formed.

FIG. 22 shows a modification in which a developing belt is used in place of the developing sleeve, in which toner is adhered to and conveyed onto the developing belt 103 stretched between rollers 134A and 134B, and the latent image on the image carrier l is developed. It was designed to do so.

Here, the roller 134A is a magnetic roller, and a bar-shaped magnet 135 pressed by an elastic body 136 comes into contact with the roller 134A through the developing belt 103, so that the l-component developer in the housing 132 is turned into a thin layer in the direction of the arrow. It is attached to the rotating developing belt 103 and conveyed to the developing area.

A cleaning brush 139 cleans toner from the developing belt 103 after development.

Note that for the developing bell 103, a thin resin film made of polyimide or the like lined with a conductive support or a conductive resin film is used.

FIG. 23 shows an example of a developing device using a magnetic l-component developer, in which the developing device is provided below the image carrier l.

Within the housing 202 is a toner supply member 211.

Half of the developing sleeve 203 is inside the toner and rotates in the direction of the arrow. There are abutting rollers 208 coaxially with the developing sleeve 203 at the front and rear of the developing sleeve 203, the abutting rollers 208 abut against the image carrier l, and the developing sleeve 2
An appropriate development interval is established between 03 and the image carrier l.

Further, a magnet roller 204 having a plurality of magnetic poles is fixed inside the developing sleeve 203, and a cylindrical rod 205 made of magnetic material is located opposite to one of the magnetic poles. The cylindrical rod 205 is brought into contact with the developing sleeve 203 by the pressing elastic member 206 to form a thin layer of toner.

The above-mentioned fixed magnet roller 204 is arranged so that magnetic poles of different polarities are alternately located in the range where toner is attached and conveyed, so that toner adhesion and conveyance performance is maintained, and the developing area 212 is positioned at magnetic poles. It is arranged so that the developing performance is improved. Further, with respect to the position of the developing sleeve buried in the toner, the distance between the magnetic poles is widened, or the magnetic poles of the same polarity are positioned so that the old toner that has passed through the developing area is peeled off. With this configuration, the latent image on the image carrier l can be satisfactorily developed by applying a developing bias of direct current or a combination of direct current and alternating current to the developing sleeve 203.

That is, the surface potential of the image carrier l side is -600V, the exposed part potential is θ~-100V, and the DC bias of the developing sleeve 203 is -1500V, and the AC bias is 70V.
When development was attempted under the condition that a voltage of 0 V ("ll5") and a frequency of 4 kHz was applied, it was confirmed that a high-quality toner image with extremely high resolution and uniform gradation could be obtained.

〔Effect of the invention〕

As described above, the developing device of the present invention includes a rigid developer carrier having a magnet or magnetic body fixed therein,
The developer layer forming section is formed by pressing a developer amount regulating body made of a magnetic material or a magnet material having the same rigidity and magnetism and a small radius of curvature, so that the rotation of the developer carrier is It is not affected by changes in speed or pressing position, and has excellent stability in conveyance amount especially against fluctuations in pressing force.
A developer layer with a stable thickness can be obtained. Therefore,
Compared to conventional products, a uniform and stable developer layer can be obtained with a lower load.

In addition, it prevents clogging caused by foreign matter (difficult spots, agglomerated toner, and developer layer pulverization properties, making it difficult for white streaks to appear on images. Also, the pressing part of the developer amount regulating member against the developer carrier) The variation in the amount of developer after regulation due to changes in pressure is extremely small, making it possible to create a developing device with excellent developing performance.Using an l-component developer, a thin layer can be formed stably and evenly, and the density can be improved. It is possible to provide images of excellent quality without causing unevenness or loss of density.

The developing device of the present invention has extremely high durability as a regulating device because the regulating member does not deform during long-term use and there is little change in the attraction force due to magnetic force.

Furthermore, even during mass production, there is a relatively large tolerance for mounting accuracy, making it highly practical.

In addition, since the developer regulating area is small, it is difficult to have an adverse effect due to unnecessary frictional charging with the developer, and a good image can be obtained.

In addition, even when the regulating member is replaced, installation is easy and maintainability is high.

In addition, when a nonlinear elastic member is used as a pressing material for the cylindrical rod, it absorbs errors in the precision of parts of the casing and holder and variations during assembly, and even without adjusting parts, stable and good development can be achieved. A developing device capable of conveying the amount of toner has now been provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the experiment that formed the basis of the present invention. FIG. 2 is a diagram showing the relationship between the presence or absence of magnetism, the curvature at the pressing part, the pressing force, and the amount of conveyance obtained by the experiment shown in FIG. 1. FIG. 3 is a configuration diagram showing the developing device of the first embodiment.
Figure 5 is a relational graph obtained by this method. FIGS. 6(a) and 6(b) are main part views showing two aspects of the toner thin layer forming portion. FIG. 7 is a graph showing the relationship between deflection and load for an example of a nonlinear elastic body. FIG. 8 is a perspective view of a main part showing how the cylindrical rod 5 is supported. FIG. 9 is a configuration diagram showing a developing device of another embodiment. 10 to 16 show various aspects of the developer layer regulating member. FIGS. 17 to 20 show various modifications of the magnet body fixedly installed within the developing sleeve. FIGS. 21 and 22 show a modification in which a magnet body is provided outside the developing sleeve or developing belt. FIG. 23 is a configuration diagram showing an example developing device using a magnetic l-component developer. l... Image carrier 3... Developing sleeve 4.1
4.24.34.44... Magnet body (magnet roller) 5... Rod-shaped body (cylindrical rod) 6.36... Spring material (elastic member) 7... Holder

Claims (1)

[Claims] a rigid developer carrier that supports a one-component developer;
A magnetic body or a magnet fixed inside the developer carrier, and a magnetic body or a magnet opposed to the developer carrier and pressed against the developer carrier to regulate the amount of developer carried on the developer carrier. a rod-shaped developer amount regulating body, the pressing part of the regulating body with the developer carrying body is made of a rigid and magnetic material, and the radius of curvature at the pressing part is 0.5 to 15 mm. A developing device characterized by: