JPH04204977A - Developing method - Google Patents

Abstract

PURPOSE:To obtain an image excellent in sharpness and resolution by causing one component developer containing gap holding particles having a uniform specified particle size to pass through a gap between a developer carrier and a developer layer regulating means. CONSTITUTION:The one component developer D is constituted of magnetic toner T and the gap holding particle (spacer particle) S, and the particle S is a magnetic particle whose diameter is larger than that of the toner T and whose particle size is uniform. When the developer D containing the particle S passes through a pressing position between the developer layer regulating member (thin layer forming bar) 110 pressed by an elastic member 42 and a developing sleeve, the gap (g) nearly equal to the particle size of the particle S is formed. The developer D which is held on the surface of the sleeve 22 and passes through the gap (g) is formed to have specified developer thickness and carried to a developing area 29, where an electrostatic latent image on an image carrier 10 is contactdeveloped so as to form a toner image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer contact type developing method used in electrostatic recording devices such as electrophotographic copying machines and facsimile machines, and particularly relates to a developing method using a -component developer. The present invention relates to a contact development method in which development is carried out by bringing a developer into contact with the surface of an image carrier carrying an electrostatic latent image.

[Background of the invention]

In an electrophotographic image forming apparatus using a one-component developer, in order to obtain good images, the layer thickness of the developer on the developer carrier (also referred to as a developing sleeve) is thin and uniform. It is necessary to.

Conventionally, the thickness of the developer layer was regulated by a fixed regulation plate, or the mechanical attachment accuracy between the developer carrier and the fixed regulation plate, the eccentricity accuracy during drive rotation of the developer carrier, and the developer carrying There is a limit to the bearing accuracy of the body, etc., so the developer layer thickness is 0.
The lower limit is about 3 mm.

With this method, it was difficult to obtain a uniform and even thin layer. However, various developer layer thickness regulating devices other than the fixed regulating plate have been proposed to meet the purpose of obtaining a uniform thin layer. For example, (a) JP-A-62-191868;
The developer layer forming device described in each publication of No. 62-191869, when using a -component developer, controls the layer thickness of the developer, which is made of a plate-shaped elastic body having a free end on one side on the developer carrier. A device that bends and presses a member to regulate the layer thickness of the developer carried on the developer carrier.

(b) In JP-A-2-50184, JP-A-2-64674, and the specification of U.S. Pat. A developing device in which a developer amount regulating body (thin layer ring) is provided opposite to the developer amount regulating body, and the developer amount regulating body is pressed against a developer carrier.

(c) JP-A-1-282578, JP-A-1-283577
A developing device in which the shape and dimensions of the developer amount regulator described in each publication are defined.

Something has been proposed.

[The problem that the invention attempts to solve]

Each of the conventionally proposed developer layer forming apparatuses has the following drawbacks.

Since the device (a) uses the pressing force generated by bending the layer thickness regulating member made of an elastic body, the pressing force is determined by the rotational speed of the developer carrier, the pressing position, the developer layer thickness, etc. It is easy to change and vibrate due to fluctuations in the image forming device, and since no measures 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

Also, with the device (b), is it possible to obtain a more stable and uniform thin layer than in (a)? Since it uses a layer thickness regulating means using a rotating body, it is difficult to loosen the aggregated particles of the developer or eliminate the aggregated particles. Its performance is poor in terms of its ability to process, and development occurs where aggregated particles are caught in the nip and pass through as the rotating body rotates, and even with intermittent rotation, satisfactory performance cannot always be obtained. ,
This causes image stains, black spots, etc., and deteriorates the image quality.

In addition, in order to maintain pressure balance, the rotating mechanism, pressure contact mechanism, etc. were complicated.

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

Furthermore, in (a) and (b), an elastic developer layer thickness regulating plate is pressed against a rigid developer carrier (metallic developing sleeve) to form a thin layer, and the elastic developer layer is formed during long-term use. It has the drawback that the plate tends to change its elastic modulus and undergo permanent deformation, and its durability as a layer thickness regulating member is short.

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 has a serious drawback in that mounting accuracy is extremely difficult during mass production.

Furthermore, in (a), (b), and (c), an elastic developer layer pressure regulating plate is pressed against a rigid developer carrier (metallic developing sleeve) to form a thin layer. However, during long-term use, the elastic plate tends to change its elastic modulus or undergo permanent deformation, and its durability as a layer pressure regulating member is short. 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 has a serious drawback in that mounting accuracy is extremely strict during mass production.

The present invention provides a developing method capable of obtaining an image with good sharpness and resolution in contact development using a one-component developer having such problems, and in particular a developer layer capable of obtaining a good image. The object of the present invention is to provide a thickness regulating method and a developing method that defines conditions in the developing area.

[Means for solving problems]

The above purpose is to supply a one-component developer onto a rotating developer carrier, transport the one-component developer while regulating the layer thickness, and form the developer onto the opposing image carrier while maintaining a predetermined gap from the developer carrier. In a developing method in which a toner image is formed by contact-developing the electrostatic latent particles with the developer in a developing region, gap-maintaining particles having a predetermined particle size and magnetism larger than the magnetic toner in the one-component developer; and a developer layer regulating member that presses the developer carrying surface of the developer carrier, and carrying and conveying the one-component developer containing the gap retaining particles on the developer carrier. The developer layer regulating member and the developer carrier are held at a predetermined gap by passing the gap holding particles between them at a position where the developer layer regulating member presses the developer carrier, and the developer layer is pressed onto the developer carrier. This is achieved by a developing method characterized by forming a uniform thin layer of developer.

Further, in the contact development method according to the present invention, an alternating current bias voltage is applied to the developer carrier and the image carrier to bind the gap holding particles in the development area to the surface of the developer carrier and to transfer the toner to the image carrier. It is characterized by being able to be transferred to the body surface.

〔Example〕

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 3 is a sectional view of a developing device using a one-component developer.

Inside the housing 21 of the developing device 20, a diaphragm 24 for preventing toner solidification on the developing roller consisting of a developing sleeve 22 and a magnet roller 23, and a toner remaining amount detection means 25 are provided.
etc. are arranged.

The developing sleeve 22 is a non-magnetic cylindrical body that rotates counterclockwise in the figure, and has a magnet roller 23 fixed therein so as not to rotate, and a part of the longitudinal surface of the developing sleeve 22 is It is exposed through the opening of the housing 21 and is disposed in parallel with and close to the image carrier 10 .

Further, a toner supply container 26 is detachably attached to the upper part of a lid member 28 that closes the upper opening of the housing 21.

In the inner concave portion of the lid member 28, there is provided a developer layer regulating member (thin layer forming rod) 40 such as a stainless steel rod having rigidity and magnetism that regulates the layer thickness of the developing material, and the thin layer forming rod 40.
A developing material layer thickness regulating means is provided, which includes a holder 41 for holding the thin layer forming rod 40, an elastic member 42 for pressing the thin layer forming rod 40, and the like.

The developing sleeve 22 and the image carrier (photosensitive drum) 10
The gap between the developing sleeve 22 and the developing sleeve 22 is always 0.5 mm because rollers (not shown) provided coaxially with the shaft end of the developing sleeve 22 abut outside the image forming area near both ends of the circumferential surface of the image carrier 10.
It is held at a certain distance between the front and back.

Here, 29 indicates the image forming body 10 and the developing sleeve 22.
A developing area 30 formed in the gap between the two is an AC bias power source that superimposes a DC voltage and an AC voltage.

The new toner supplied from the toner supply container 26 is housed in the housing 21, is agitated by the vibration of the diaphragm 24, and is further deposited in a layer on the circumferential surface of the developing sleeve 22, which rotates counterclockwise in the figure. It is conveyed and passes through the pressing position of the thin layer forming rod 40 to form a predetermined thin layer.

FIG. 4 is a longitudinal sectional view of the developer layer thickness regulating means.

Elastic members 42 are attached to a portion of the inner wall of the groove portion 21A of the housing 21 at a plurality of locations. The thin layer forming rod 40 is dropped into the recess formed by the elastic member 42 and the groove 21A. Then, a holder 41 is inserted into the center holes 40A, 40A at both ends of the thin layer forming rod 40.
The tips of the projections 41A and 41A are loosely inserted.

The holder 41 is fixed to both sides of the housing 21 with screws. In this way, the thin layer forming rod 40 will not fall off or come off the holder 41. Of course, the fit between the protrusion 41A and the center hole 40A should be loose so that there is enough room to prevent them from coming off.

The magnetic thin layer forming rod 40 has a magnetism opposite to that of the magnet roller 23 facing it, and the pressing force against the developing sleeve 22 is generated by the cooperation of its attractive magnetic force and the elasticity of the elastic member 42. That's how you get it. Then, the developer carried onto the developing sleeve 22 is overcome by the pressing force between the magnetic thin layer forming rod 40 and the elastic member 42, lifts the thin layer forming rod 40, and passes through the gap created at the pressure contact position. By doing so, a uniform developer layer setting thickness (0.3 mm in this case) can be obtained. The gap corresponds to the set gap (here, 0.5 mm) of the developing area 29 between the image carrier 10 and the developing sleeve 22, so that optimal development can be performed.

After that, the developer remaining on the developing sleeve 22 after the development is returned to the housing 21 of the developing device 20, scraped off from the surface of the developing sleeve 22 by the scraper 27, and then returned to the developing sleeve 22. development is carried out continuously.

In the developer layer thickness regulating means, for example, the thin layer forming rod 40 is a rigid and magnetic stainless steel rod with a diameter of 6 mm, and the thin layer forming rod 40 is connected to the magnetic roller 2.
When a load of (2 to 6) gf/am was applied to the position facing the magnetic pole No. 3, a developer conveyance amount of 1 mg/cof was obtained. At this time, the magnetic flux density at the pressed position on the surface of the developing sleeve 22 was 600 Gauss.

Instead of the magnetic thin layer forming rod 40, a non-magnetic cylindrical rod having a diameter of 6 mm and rigidity, or each of the cylindrical rods covered with a rubber layer may be used.

Further, regarding the amount of developer conveyed when using the thin layer forming rod 40 having rigidity and magnetism, when the diameter of the thin layer forming rod 40 is changed, the pressing force and the amount of developer conveyed change.

Furthermore, even if the material of the rigid developing sleeve 22 is a non-magnetic stainless steel pipe, a metal pipe such as aluminum, or a rigid pipe material such as hard resin, glass, or ceramic, the pressing force will vary. This causes a change in the amount of developer conveyed.

When the pressing force of the thin layer forming rod 40 is increased, the amount of developer conveyed per unit area on the developing sleeve 22, that is, the thickness of the developer layer becomes approximately constant regardless of fluctuations in the pressing force.

On the other hand, if the pressing force is small, the amount of developer conveyed per unit area increases or changes significantly due to fluctuations in the pressing force, resulting in instability.

Therefore, in order to obtain a stable amount of developer conveyed, it is necessary to increase the pressing force of the thin forming rod. However, increasing the pressing force places an excessive load on the toner, resulting in greater damage and faster deterioration.

This causes toner deterioration, toner adhesion and fusion to the developing sleeve 22, and developer aggregation.

Furthermore, the surface roughness of the developing sleeve 22 also causes a difference in the amount of developer conveyed.

FIG. 1 is an enlarged sectional view of essential parts of the developing device 20. As shown in FIG.

FIG. 2 is an enlarged sectional view showing an example of application of the method for forming the thickness of a developer layer according to the present invention.

The one-component developer according to the present invention consists of a magnetic toner T coated with a resin containing a colorant, and gap holding particles (spacer particles) S coated with the resin, the specifications of which are shown in the table below. It is.

Table 1 The above spacer particles S are spherical magnetic particles having a uniform particle size. Then, the spacer particles S and the magnetic toner T were added at a weight ratio of 1/2:l.

As a result of experiments conducted under the above conditions, when the developer layer containing the spacer particles S passes through the pressing position of the developer layer regulating member (thin layer forming rod) 40 pressed by the elastic member 42 and the developing sleeve 22 , forming a gap approximately equal to the particle size of the spacer particles S. The developer layer held on the surface of the developing sleeve 22 and passed through the gap forms a predetermined developer thickness and is conveyed to the developing area 29, where the electrostatic latent image on the image carrier 10 is developed by contact. to form a toner image.

Further, since the magnetic spacer particles S are attracted and conveyed on the developing sleeve 22, the conveyance force of the magnetic toner T is also strengthened, and toner clogging at the pressed position by the thin layer forming rod 40 is reduced.

Furthermore, the flow of the magnetic toner T in the developing region 29 where the developing sleeve 22 and the image carrier 10 face each other has also been improved. Furthermore, magnetic ears can be made neatly and uniformly,
In addition to stabilizing the developability, the setting latitude of the developing device has been expanded.

As a result of experiments, the spacer particles S having magnetism that are compatible with this method of forming a developer layer have a particle size larger than the particle size of the magnetic toner T in the one-component developer, and are preferably between 30 and 150 μm. Met. In addition, the mixing ratio of spacer particles S on the developing sleeve 22 was determined by the magnetic toner T in the above experiment.
Approximately 1/2 in terms of weight ratio was suitable, but 1/3 to 2
It was possible to implement within the range of /3.

In addition, whether experiments were conducted on iron powder or ferrite as the material of the spacer particles S, or whether the difference in material did not have much effect, or whether the spacer particles S with a low resistance value and a small particle size are attached to the image carrier 10 by electrostatic induction. Because of the adhesion, good results could not be obtained.

Furthermore, the spacer particles S are more strongly attracted to the developing sleeve 22 by magnetic force than the magnetic toner T, and therefore are not moved toward the image carrier 10 side. That is, since it is not drawn into the toner image together with the magnetic toner T, it remains on the surface of the developing sleeve 22 and is not consumed even if development is repeated.

Furthermore, since the spacer particles S are only added in a small amount in terms of volume, and their electrical properties are not originally used,
It does not undergo much change over time, and even if it becomes magnetically magnetized, it is not a big problem, and it is sufficient to just add it to the developer. Of course, it may be replaced.

Further, the spacer particles S have a remarkable effect not only on layer thickness regulation and transportability in conventional one-component development, but also on improving cohesiveness. In particular, magnetic toner T at high humidity
Although the particles tend to aggregate, the movement of the spacer particles S helps to resolve and crush the aggregates within the housing 21.

Note that when weakly magnetic or non-magnetic spacer particles S having a low resistance value are used, the image carrier 10 is arranged above the developing sleeve 22, and the image carrier 10 is conveyed along with the toner T over the developing sleeve 22 to the developing area. In the process of reaching , spacer particles S
prevent it from moving or falling off due to its gravity.

Since the developer layer has a thickness of about 100 μm to 450 μm, contact development is possible by narrowing the gap g1 between the image forming body 10 and the developing sleeve 22, that is, around 300 μm of the developing cap. When the development gap is narrowed in this way, the electric field in the development region 29 becomes larger, so that sufficient development can be achieved even if the development bias applied to the development sleeve 22 is reduced, and there is an advantage that leakage discharge of the development bias is also reduced. be. Furthermore, the resolution and other image quality of images obtained by development are generally improved.

In order to improve image quality, it is effective to narrow the development gap, but if the tip of the carrier C approaches the surface of the image bearing member 20, carrier adhesion will easily occur, so there is a limit to how close it can be. The limit of the gap that can be approached is about 300 μm as mentioned above.

The present inventors have determined that for a developing device having a similar configuration to the above-mentioned developing device, under basic conditions or within the range shown in Table 2, the AC component of the developing bias VAC1, the DC component of the developing bias Vs,
Conditions with good reproducibility were determined by varying the developing bias frequency n KHz, the non-image area potential V□ of the image carrier IO, and the like.

The following trends were observed during the experimental process.

(1) It is desirable that IVM −Vl + be small.

When the size becomes larger, carrier adhesion tends to occur in non-image areas. However, if it is close to 0, fogging will occur.

(2) It is better to set the surface potential vH of the photoreceptor to a large value since there may be potential fluctuations in consideration of deterioration and fatigue of the photoreceptor.

(3) When VA becomes large, leakage occurs and carrier adhesion occurs. The lower the VAC, the better.

In addition to the above general trends, it has become clear that there is a specific relationship between IVM-Vll, developing bias frequency (KHz), AC applied voltage VACN, and image quality. Note that here IV) II>IVBI is the condition during reversal development,
lV, l<IVBI are conditions during regular development.

The specifications of each component included in the embodiment of the developing device of the present invention shown in FIG. 2 are as follows.

The developing sleeve 22 is made of a thin cylindrical stainless steel material with an outer diameter of 20 mm, and the outer peripheral surface is honed to a roughness of 3 μm, and is rotated at 200 to 300 revolutions per minute, in this embodiment, 250 revolutions per minute. It is rotated clockwise. The diameter of the developing sleeve 22 may be determined by whether a small diameter sleeve is required due to the miniaturization of the developing device or by the built-in magnetic roller 2.
It is set to 15 to 30 mm based on the magnetic force limit of No. 3.

Also, various experiments were conducted regarding the rotation speed of the developing sleeve 22, and it was found that when the rotation speed is low, the amount of developer supplied is small.
The image density when the latent image is developed is also low. Outer diameter 20II1
Looking at the developing sleeve 22 of m, the rotation speed is 0 per minute.
The maximum image density increases linearly between 200 rotations per minute and reaches a saturated state at 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.

The relative position between the developing sleeve 22 and the thin layer forming rod 40 is the first
As shown in the figure, the thin layer forming rod 40 is pressed against the developing sleeve 22 at a position facing the magnetic pole of the magnet roller 23, and is also attracted by the induced magnetic force, increasing the pressing force and uniformly covering the developing sleeve 22. It works so that it sticks closely to the

As a means for pressing the thin layer forming rod 40, the elastic member 42 may be a rubber-like elastic body or a resin foam. Alternatively, an adjustable leaf spring or coil spring may be used as the elastic member 42.

Further, the thin layer forming rod 40 is not limited to a cylindrical shape, but is a columnar body having a quadratic curved cross section in the portion that contacts the developing sleeve 22, for example, a rod-shaped developer layer with a radius of curvature of 1 to 15 mm. It may also be used as a regulating member.

Alternatively, at least the pressing portion of the thin layer forming rod 40,
Thin rubber materials such as urethane rubber or silicone rubber,
Alternatively, the pressing portion may be covered with a cured resin layer or a hard glass layer. The thickness of the coating layer of the rubber material is 0801 to 1
Approximately mm or so is preferable.

Further, the thin layer forming rod 40 is preferably a magnetic rod-shaped body made of a rigid material having magnetism, a magnet that generates a magnetic field, or a columnar body in which magnetic particles are enclosed and the outside is coated with a hard material. But that's fine.

In this apparatus, when the thin layer forming rod 40 was made of polycarbonate having a diameter of 6 mm and had a rigidity, and a load of 2 to 4 gf/square was applied, a uniform and even magnetic ear was obtained. As a result, an image with stable density and no unevenness was obtained.

In addition, in this developing device, even if the thin layer forming rod 40 is made of a resin material such as Bakelite, or a metal such as stainless steel or aluminum, and the rubber elastic member 42 is made of silicone rubber, fluororubber, etc., the amount of conveyance may be affected. By setting the diameter and pressing force of the thin layer forming rod 40 and the particle size of the space particles S, it was possible to select an appropriate conveyance amount.

It should be noted that equivalent hardening was obtained even when non-magnetic stainless steel was used as the material of the developing sleeve 22, or a rigid material such as aluminum metal, hard resin, glass, or ceramic was used. For the surface roughening of the developing sleeve 22, 3S was used. A similar effect was obtained when a surface roughness of 0.1 to 20S was used. Similar results were obtained for other materials.

FIG. 5 is an enlarged sectional view showing another embodiment of the developer layer regulating means used in the developer layer forming method of the present invention;
The figure is an enlarged view of the main parts.

In these figures, a drum-shaped image carrier 10 has an electrostatic image formed on its surface by a charging and exposing device (not shown), and rotates in the direction of the arrow. The developer transport carrier provided close to the image carrier 10 is composed of a developing sleeve 22 made of a non-magnetic material such as aluminum, and a magnet roller 23 having a plurality of magnetic poles in the circumferential direction. is one in which 8 S poles and 8 N poles are arranged alternately, and the magnetic field on the developing sleeve 22 is 50C1-
1500 GauSS is preferable, and in this example 700 Gau
I used a ss magnet roll. The non-magnetic developing sleeve 22 is desirably made of stainless steel with an uneven surface of 1 to 10 μm. In this embodiment, the non-magnetic sleeve 22 is made of cylindrical material with a diameter of 20 mm and has a roughness of 3 μm. A sleeve was used. The rotation speed of the developing sleeve 22 is (1
00-500) rpm, in this example (240) rpm
The rotational speed of the magnet roller 23 is 2 to 5 times that of the developing sleeve 22, and in this example is 800 rpm. In order to convey the developer pool from the developer reservoir to the developing area 29, the developing sleeve 22 is fixed and the magnetic roller 23 is rotated, or conversely, the magnetic roller 23 is fixed and the developing sleeve 22 is rotated. Alternatively, it is possible to rotate both by 22 degrees and 23 degrees. However, the direction in which the developer is conveyed is the same as the direction of rotation of the developing sleeve 22 when it rotates, but is opposite to the direction of rotation when the magnet roller 23 rotates.

In FIG. 5, the magnet roller 23 is fixed and the developing sleeve 22 is rotated counterclockwise.
The magnetic flux density of the magnetic pole facing the is larger than that of the other magnetic flux densities. In order to further increase the magnetic flux density of the magnetic pole facing the image carrier lO, two magnetic poles of the same or different polarity may be placed close to each other.

The thin layer forming plate (elastic plate) 50 is fixed to a holding member 51. The thickness of the thin layer forming plate 50 is 0.05 to 0.
It is appropriate that the range is between 2m+*, and in this example, it is 0.
It was set to 1 mm. Further, the elastic modulus of the thin layer forming plate 50 is 500 (
A suitable value is 1-25000 kgf/mm2, and in this example, it is 11000 kgf/am2. Further, the material of the thin layer forming plate 50 is preferably stainless steel, beryllium copper, brass, steel, etc., but in this embodiment, phosphor bronze was used. The length (free length) from the position where the thin layer forming plate 50 is fixed to the holding member 51 to the tip of the elastic plate 50 is suitably between 5 and 20 m, and is 15 m in this embodiment. It is arranged so that it contacts the developing sleeve 22 at a position 1- from the tip, and its linear pressure is suitably between 1 and 10 g/mm, and is Ig/- in the embodiment.

The developer layer carried and conveyed on the peripheral surface of the developing sleeve 22 by the magnetic force of the magnet roller 23 is formed into a developer layer of a predetermined thickness (in this example, (25 mm) by the thin layer forming plate 50.
0 μm to 450 μm)) is further conveyed and reaches the developing area 29, a part of which is sucked into the image carrier 10, and the rest is conveyed on the circumferential surface of the developing sleeve 22 in the direction of the arrow and is sent to the scraper. 27 from the circumferential surface of the developing sleeve 22.

A one-component developer consisting of magnetic toner T and spacing particles (spacer particles) S is adsorbed and conveyed to the surface of the developing sleeve 22 that is in pressure contact with the thin layer forming plate 50 having such a structure. At this time, the developing sleeve 2
The gap g between 2 and the thin layer forming plate 50 is regulated and maintained at a predetermined gap through which the particle size of the spacer particles S can pass, and the developer layer after passing through this gap has a predetermined thin layer thickness and is formed in the development area. 29.

FIG. 7 shows that the pressure contact surface of the thin layer forming plate 50 is connected to the developing sleeve 2.
This is an example in which the device is installed in a sweeping direction with respect to the rotation direction of No. 2. In this case as well, the gap g is kept constant by the intervening conveyance of the spacer particles S.

FIG. 8 is a sectional view showing the structure of still another embodiment of the developer layer regulating means used in the developer layer forming method of the present invention.

In this embodiment, a rubber elastic plate 52 is used as a developer layer regulating member on the thin layer forming plate 50 made of metal or synthetic resin.
It is a layered structure.

FIG. 8(a) shows the rubber elastic plate 52 having a thickness of 0, 1 to 1.
A rubber member such as polyurethane with a thickness of 2.0 mm and a rubber hardness of 40 to 906H8 is used, and the thin film forming plate 50 is a thin metal plate such as a phosphor bronze plate or a stainless steel plate with a thickness of 0.05 to 0.5N, or a thin metal plate such as a phosphor bronze plate or a stainless steel plate with a thickness of 0. .1-1. Using a resin board such as ow's polyethylene terephthalate (PI!T),
A rubber elastic plate 52 is attached using an adhesive tape, an adhesive, or heat fusion, and this is attached to the holding member 51 via a double-sided adhesive tape.

Adhesive may be used instead of double-sided adhesive tape.

FIG. 8(b) shows an example in which the rubber elastic plate 52 and the thin layer forming plate 50 are stacked on top of each other without being pasted, and are mechanically sandwiched between the holding members 51.

Here, the abutment position and deformation amount between the rubber elastic plate 52 and the developing sleeve 22 are determined by the pressing force and the amount of play at the tip according to Japanese Patent Application Laid-Open Nos. 62-191868 and 62-191869.

In this example, a rubber elastic body is used to line the part of the rubber elastic plate 52 that comes into contact with the one-component developer, so that it is possible to press the developing sleeve 22 uniformly, and the developer is deposited. Also, a uniform and stable developer layer can be formed.

In both the above examples (a) and (b), the rubber elastic plate 5
When 2 is pasted or sandwiched,
Even if there is some distortion, the metal or synthetic resin thin layer forming plate 5
This allows the rubber elastic plate 52 to be pressed down to zero, thereby preventing the rubber elastic plate 52 from waving and allowing uniform layer formation to be performed stably over a long period of time.

In FIG. 9, a rubber elastic plate 52 is attached only to the portion of a thin layer forming plate 50 made of metal or synthetic resin that comes into contact with the developing sleeve 22. The rubber elastic plate 52 has a rubber hardness of 4
The holding member 51 is made of rubber such as polyurethane having a temperature of 0 to 90°Hs, preferably 50 to 70°Hs, and has a thickness of 1 to 3 degrees.
It is fixed at . In this example as well, the stabilization of the developer layer formation by the rubber elastic plate 52 and the measures against distortion can be satisfied.

As described above, in this embodiment of the developer layer thickness regulating means according to the present invention, a plate-shaped elastic body made of metal or synthetic resin is provided on the surface of the rubber elastic plate 52 opposite to the surface in contact with the developing sleeve. (Thin layer forming plate 50) is bonded, surface-contacted, or line-contacted, so that the waving phenomenon that occurs when only a thin rubber elastic body is used does not occur.

Also in the developing device using the developer layer thickness regulating means shown in FIGS. 8 and 9, the gap retaining particles (spacer particles) S contained in the one-component developer consisting of the magnetic toner T are Since the gap at the pressure contact position between the sleeve 22 and the thin layer forming plate 50 is regulated to a gap corresponding to the particle size of the spacer particles S, the developer layer that has passed through the pressure contact position has a predetermined thin layer thickness.

〔Effect of the invention〕

As described above, the non-contact developing method of the present invention includes a one-component developer containing gap-maintaining particles having rigidity and a predetermined uniform particle size, and transporting the particles onto a developer carrier. By applying pressure with the developer layer regulating member and performing contact development by applying an AC bias voltage in the development area, the gap-holding particles in the developer are bound on the development sleeve, while the toner image bearing Transfers to the body and forms a toner image.

This reduces the influence of the electric field at the image edges,
The reproducibility of fine lines and fine text has improved, making it possible to obtain good image quality.

Furthermore, since the gap retaining particles of the present invention support the pressing force of the developer layer thickness regulating member, problems such as toner deterioration, toner adhesion or fusion to the developing sleeve, and developer aggregation are solved.

Furthermore, it is less likely to cause clogging due to foreign matter, and has excellent pulverization properties for agglomerated toner and developer layers, making it difficult for only white smear to appear on images. In addition, fluctuations in the amount of developer after regulation due to changes in the pressing force of the pressing portion of the developer amount regulating member against the developer carrier are extremely small, making it possible to provide a developing device with excellent developing performance, thus achieving stable unevenness. It is possible to form a thin layer without any blemishes, and it is possible to provide an image of excellent quality without causing density unevenness or density reduction.

The developing device according to the present invention has extremely high durability as a regulating device because the developer layer 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, good images can be obtained without causing adverse effects due to unnecessary frictional electrification with the developer.

In addition, even when replacing the regulating member, it is easy to install and maintainability is high.

In addition, when using a nonlinear elastic member as a pressing material for the thin layer forming rod, it is necessary to absorb errors in the precision of parts of the case song and holder, as well as variations during assembly. Therefore, a developing device capable of transporting a good amount of developer has been provided.

Further, by incorporating the gap maintaining particles according to the present invention into a one-component developer, there is a remarkable effect not only in regulating the developer layer thickness and improving transportability but also in improving the cohesiveness of the developer.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of essential parts of a developing device to which the developing method of the present invention is applied; FIG. 2 is an enlarged cross-sectional view illustrating gap-holding particles according to the present invention; FIG. 3 is a cross-sectional view of the developing device; Figure a$4 is a longitudinal sectional view of the developer layer thickness regulating means, and Figure 5 is an enlarged sectional view of the thin layer forming plate and the developing sleeve. FIG. 6 is a partial enlarged cross-sectional view of these press-contact positions, FIG. 7 is an enlarged cross-sectional view showing another embodiment of the thin layer forming plate, and FIGS. 8 and 9 are still other embodiments of the thin layer forming plate. It is a sectional view showing an example. 10... Image carrier (photosensitive drum) 20... Developing device 21... Housing (casing) 22... Developing sleeve (developer carrier) 23...
Magnet roller 28...Top lid member 29...Development area 30...
- AC bias power supply 40...developer layer regulating member (thin layer forming rod) 41...
Holder 42...Elastic member 50...Developer layer regulating member (thin layer forming plate) 51...Holding member 52
...Rubber elastic plate D...-component developer S...gap holding particles (spacer particles) T...magnetic toner g...gap Figure 1 Section in Figure 7

Claims (2)

[Claims] (1) A one-component developer is supplied onto a rotating developer carrier, transported while controlling the layer thickness, and formed on an image carrier facing the developer carrier while maintaining a predetermined gap. A developing method in which a toner image is formed by contact-developing an electrostatic latent image with the developer in a development area, wherein gap-maintaining particles having a predetermined particle size and magnetism larger than the magnetic toner in the one-component developer are used. At the same time, a developer layer regulating member is provided that presses the developer carrying surface of the developer carrier, and the one-component developer containing the gap retaining particles is supported and conveyed on the developer carrier. , the developer layer regulating member and the developer carrier are held at a predetermined gap by passing the gap holding particles between them at a position where the developer layer regulating member presses the developer carrier, and the developer layer is placed on the developer carrier. A developing method characterized by forming a uniform thin layer of developer. (2) Applying an AC bias voltage to the developer carrier and the image carrier to bind the gap holding particles in the development region to the developer carrier surface and to enable the toner to transfer to the image carrier surface. The developing method according to claim 1, characterized in that: