JPH0980910A - Image forming device - Google Patents

Abstract

(57) [Summary] (Correction) [Problem] To maintain a constant amount of toner on the developing sleeve,
Even when used for a long period of time, deterioration of image density and image deterioration such as fog are prevented, and stable and good images are obtained. SOLUTION: A straight line u passing through the most upstream point in the developing sleeve rotation direction and the center of the developing sleeve 3 in the contact portion between the elastic blade 4 and the developing sleeve 3, and the center point of the contact portion between the supply roller 5 and the developing sleeve 3. And an angle formed by a straight line t passing through the center point of the developing sleeve is 50 degrees or more and 80 degrees or less, and the most upstream point in the developing sleeve rotation direction in the contact portion between the elastic blade 4 and the developing sleeve 3 and the elastic blade 4 abut. The toner agglomeration degree in the area surrounded by the free end point of the contact surface, the vertical line L passing through the free end point of the elastic blade contact surface, and the peripheral surface of the developing sleeve is always 10% or more and 40% or less, The linear pressure between the elastic blade 4 and the developing sleeve abutting part is 5
g / cm or more and 30 g / cm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, an image recording apparatus, a printer, and a facsimile, which is formed on an image carrier made of an electrophotographic photoreceptor or an electrostatic recording dielectric. The developing device is characterized in that the electrostatic latent image is developed using a one-component developer containing no carrier.

[0002]

2. Description of the Related Art Hitherto, various types of dry one-component developing devices have been proposed and put into practical use. However, it is extremely difficult to form a thin layer of a dry one-component developer in any developing device. However, the sharpness of the developed image,
At present, when the improvement of resolution and the like is required, it is essential to develop a method for forming a thin layer of a dry one-component developer and its apparatus, and in response to this, some measures have been proposed.

[0003] For example, an apparatus as disclosed in JP-A-54-43038 can be mentioned. In this apparatus, a rubber or metal elastic blade as a developer regulating means is brought into contact with a developing sleeve as a developer carrying member, and a developer (hereinafter referred to as toner) is made to intrude from the abutting portion to pass over the developing sleeve. A thin toner layer is formed on the surface of the toner, and the electric charge due to frictional charging at the contact area (hereinafter referred to as tribo)
Is imparted to the toner.

When magnetic toner is used in such an apparatus, if a magnet is provided in the developing sleeve, the magnetic force of the magnet can supply the toner onto the developing sleeve. However, the use of non-magnetic toner requires a new mechanical supply means. Therefore, the present applicant has proposed the following developing device in Japanese Patent Application Laid-Open No. 58-116559. That is, in this apparatus, a supply roller, which is a developer separating means, is arranged on the upstream side of the contact portion between the elastic blade and the developing sleeve in the rotating direction of the developing sleeve so as to contact the developing sleeve, and the toner is supplied to the developing sleeve and the developing sleeve. The upper undeveloped toner is being stripped. With this simple structure, high concentration,
It is possible to faithfully reproduce a wide-area solid black image and provide a stable image at all times.

[0005]

However, in the developing device construction of the above-mentioned conventional example, demand for higher speed and higher durability has been increasing in recent years. There is a need to provide stable images of equivalent quality for a long period of time. For that purpose, it is a prerequisite that the amount of toner coated on the developing sleeve is kept constant. No matter how the developing electric field is set, if the toner amount on the developing sleeve is smaller than the proper amount, it is not possible to maintain a constant image density, and if the toner amount on the developing sleeve is larger than the proper amount, A large amount of toner cannot obtain a sufficient amount of charge due to friction with the sleeve and the blade, and fogging occurs in the non-image area. Further, due to the reciprocating motion between the sleeve and the drum due to the alternating electric field, it is difficult to maintain the toner having a low charge amount on the developing sleeve or the drum, which causes an increase in scattered toner.

Even if there is a difference in sleeve coating speed, toner, and charging characteristics of the blade, the sleeve coat amount that does not cause such a harmful effect is the weight of the toner layer on the sleeve per unit area (hereinafter referred to as M / S). Is 0.35
It may be in the range of 0.55 (mg / cm ² ).

[0007] The reason why the proper range of the toner coat amount on the sleeve is not maintained is a change in toner cohesion. According to the research conducted by the present inventors, the degree of toner aggregation has a great influence on the toner coat amount on the sleeve, and is a factor that fluctuates greatly during long-term durability. Although the reason why the toner cohesion greatly changes is not fully clear, it is considered that moisture absorption occurs due to long-term storage, coagulation due to the weight of the toner itself, and mechanical and physical adhesive force changes between toners due to toner deterioration. Conventional durability 3000
A developing device that allows for approximately one sheet can be used up without much fluctuation, but when longer durability is required, it is necessary to reduce the change in the amount of coat on the sleeve due to the fluctuation in toner cohesion. .

Even if the developing electric field is set outside the range of the amount of coat on the sleeve as described above, a high quality image cannot be obtained. However, even in such a range of cohesion, an appropriate developing electric field can be obtained. If it is not formed, a sufficiently high quality image cannot be obtained.

If the toner supply roller is a conventional fur brush or an elastic roller made of open-cell foam,
In particular, when a toner having a small particle size is used, or when the toner is used under high temperature and high humidity, the toner is gradually clogged inside the roller during a large number of repeating development operations, and the roller is hardened. For example, in the case of a fur brush, each fiber is in communication with each fiber, and in the case of an open-cell foam, each air bubble is in communication, so that the toner is clogged inside. When the roller is hardened, the contact pressure of the roller against the sleeve becomes excessively large, and the force of rubbing the toner to the sleeve works greatly, and the toner is fused onto the sleeve, the toner deteriorates, and the fog increases, Also, the driving torque of the roller increases. Further, the scraping of the toner becomes non-uniform in the longitudinal direction, and the coating and the stripping are non-uniform.

Therefore, in order to prevent such inconvenience due to hardening of the roller, it has been proposed to use a foam having a single cell structure. However, when the developing operation is repeated for a further long period of time, even if the foam is a single-cell foam, air bubbles are present on the roller surface. Such,
There has been a problem that the toner is clogged with the bubbles on the surface or is fused.

Therefore, a first object of the present invention is to provide an image forming apparatus provided with a developing device capable of maintaining a constant amount of the developer on the developer carrying member.

A second object of the present invention is to prevent image deterioration such as image density change and fog during long-term use,
An object of the present invention is to provide an image forming apparatus provided with a developing device capable of obtaining a stable and good image.

[0013]

The above object can be achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A rotatable developer carrying member for carrying and transporting a non-magnetic one-component developer contained in a developer containing container to a developing section, and a rotatable developer supply provided in contact with the developer carrying member. Means, and an elastic regulating member that abuts on the downstream side of the developer supplying means in the rotation direction of the developer carrying member to regulate the amount of the developer applied to the developer carrying member, and In an image forming apparatus provided with a developing device for performing non-contact development by forming an alternating electric field in a gap between a latent image carrier to be formed and the developer carrier, the elastic regulating member and the developer carrying member are brought into contact with each other. A straight line passing through the most upstream point in the rotation direction of the developer carrying member and the center of the developer carrying member, the center point of the contact portion between the developer supply means and the developer carrying member, and the developer carrying member. Angle with the straight line passing through the center of A straight line that is not less than 80 degrees and is the most upstream point in the contact direction of the elastic restriction member and the developer carrying member in the rotation direction of the developer carrying member, and a free end point of the elastic restricting member contact surface; The degree of cohesion of the developer in the area surrounded by the vertical line passing through the free end point of the elastic regulation member contact surface and the peripheral surface of the developer carrying member is always 10% or more and 40% or less, The linear pressure between the elastic regulating member and the developer carrying member contacting portion is 5 (g / cm) or more 30
The image forming apparatus is (g / cm) or less.

The alternating electric field formed in the gap between the latent image bearing member and the developer bearing member has a peak value on the side where the developer is moved to the latent image bearing member side. It is preferable to have a bias waveform larger than the peak value for pulling back to the developer carrying member side. 4. The maximum electric field of the alternating electric field formed in the gap between the latent image carrier and the developer carrying member is 4.9 × 10 ⁶ (v / m) or more.
It is preferably 4 × 10 ⁶ (v / m) or less. The frequency of the alternating electric field is preferably 1.0 kHz or more and 8.0 kHz or less.

It is preferable that the developer supplying means is composed of a foam having a single foam structure. A vertical line that has a developer stirring member, and a central axis of the developer stirring member passes through the most upstream point with respect to the rotation direction of the developer carrying member in the contact portion between the developer carrying member and the elastic restriction member. And a vertical line which is in contact with the developer supplying means, and which is farthest from the developing portion of the developer carrying member, and is preferably rotated in the same direction as the developer carrying member. . The image forming apparatus has a control mechanism in which the developer carrying member and the developer supplying unit are driven after the power is turned on and before the image forming operation is started.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. In the embodiments described below, the present invention is described as being embodied in an electrophotographic image forming apparatus as shown in, for example, FIG. 6, but the present invention is not limited to this.

In FIG. 6, the electrophotographic image forming apparatus is provided with a photosensitive drum 1 which is an image carrier rotatably, the photosensitive drum 1 is uniformly charged by a primary charger 14, and then, for example, of a laser. The information signal is exposed by such a light emitting element 15 to form an electrostatic latent image, which is visualized by the developing device 20. Then, the visible image is transferred onto the transfer paper 17 by the transfer charger 16 and further fixed by the fixing device 18 to obtain a permanent image. Further, the transfer residual toner on the photosensitive drum 1 is removed by the cleaning device 19.

In FIG. 1, the photosensitive drum 1 is a developing device 2
It is arranged to face 0 and rotates in the direction of arrow A. The photosensitive drum 1 is, for example, a so-called xerographic photoreceptor having an electrostatic latent image formed by the Carlson process, Japanese Patent Publication No. 42-2.
No. 3910, a photoreceptor having an insulating layer on the surface on which an electrostatic latent image is formed by the NP process, an insulator on which a latent image is formed by an electrostatic recording method, and an insulator on which an electrostatic latent image is transferred by a transfer method. , And other members having an electrostatic latent image (or potential latent image) formed and held by an appropriate method.

The developing device 20 includes a developer supply container (hereinafter simply referred to as a container) 2, a developing sleeve 3 as a developer carrying member, an elastic blade 4 as a developer regulating member, and a supply as a developer supply / separation means. And a roller 5.

The container 2 has an opening extending in the longitudinal direction of the developing device 20 (direction perpendicular to the paper surface), and the developing sleeve 3 is disposed in the opening.

The developing sleeve 3 is made of a non-magnetic material such as SUS or aluminum and has a surface as described later. In FIG. 1, the developing sleeve 3 has a right substantially half peripheral surface projecting into the container 2 and a left substantially half peripheral surface exposed to the outside of the container 2 so as to be rotatably supported by the developing sleeve 3 in the direction of arrow B. Is driven to rotate. The developing sleeve 3 is not limited to a cylindrical body (sleeve), and may be in the form of an endless belt that is rotationally driven. Alternatively, a rubber roller may be used. The exposed surface of the developing sleeve 3 outside the container faces the surface of the photosensitive drum 1 with a slight gap.

Behind the developing sleeve 3, a supply roller 5 is provided.
Are arranged so as to rotate in sliding contact with the surface of the developing sleeve 3 that projects into the container. The supply roller 5 rotates in the same direction as the developing sleeve 3 (direction of arrow C in the drawing) to supply the toner to the developing sleeve 3 and elastically contact the developing sleeve 3 to peel off the toner on the developing sleeve 3.

An elastic blade 4 is disposed in contact with the developing sleeve 3 on the downstream side of the sliding contact portion between the supply roller 5 and the developing sleeve 3 in the rotation direction of the developing sleeve 3, and the developing sleeve 3 is in contact at the corresponding contact portion. The passage of the toner above 3 is regulated.

In the present embodiment, first, the toner 6 supplied near the developing sleeve 3 by the rotation of the supply roller 5 enters the contact portion between the elastic blade 4 and the developing sleeve 3 by the rotation of the developing sleeve 3 to develop the toner. It is carried on the surface of the sleeve 3.

Further, when the toner 6 passes through the contact portion between the elastic blade 4 and the developing sleeve 3, the toner 6 is brought into sliding contact with the surface of the developing sleeve 3 by the elastic blade 4, and is further subjected to frictional electrification. In this way, the toner 6 can receive sufficient triboelectrification.

The toner 6 which has been subjected to sufficient triboelectrification passes through the contact portion and is formed as a thin toner layer on the developing sleeve 3, and is carried on the developing sleeve 3 to the developing portion facing the photosensitive drum 1. In the developing section, a part of the toner is consumed by the developing operation, and the other toner is collected from the lower part of the developing sleeve 3. A seal member 9 is provided in this collecting portion to allow passage of the toner not consumed in the development into the container 2 and prevent the toner 6 in the container 2 from leaking from the lower portion of the container 2. The collected toner 6 on the developing sleeve 3 is scraped off by elastic contact at the sliding contact portion between the supply roller 5 and the developing sleeve 3.

Most of the scraped toner 6 is conveyed by the rotation of the supply roller 5 and mixed with the toner in the container 2 to disperse the charge of the charged toner. At the same time, new toner is supplied onto the developing sleeve 3, and tribo is imparted to the developing sleeve 3 again at the contact portion between the elastic blade 4 and the developing sleeve 3, and the toner is conveyed to the developing portion.

In this way, the undeveloped toner on the developing sleeve 3 is scraped off, so that the toner on the developing sleeve 3 is replaced and the toner is prevented from being excessively charged, that is, charged up.

FIG. 2 is a view showing the positional relationship between the supply roller 5 and the developing sleeve 3. The most upstream point D in the sleeve rotation direction of the contact portion between the elastic blade 4 and the developing sleeve 3.
And the straight line passing through the center 01 of the developing sleeve 3 is u,
Center point E of the contact portion between the supply roller 5 and the developing sleeve 3
And a straight line passing through the center O1 of the developing sleeve is t (t is a straight line passing through the center O2 of the supply roller 5), the angle θ formed by the straight lines u and t is 40 to 120 degrees, preferably 5 degrees.
By setting the angle to 0 to 80 degrees, the same toner stays and agglomerates in a narrowly closed area near the arc DE on the peripheral surface of the developing sleeve, and the same toner is excessively supplied from the supply roller or the blade many times. It is possible to mitigate the situation in which the physical properties of a load change gradually and the image deteriorates.

It is also advantageous in arranging the stirring member in this area that the area is not too narrow. If the angle formed by the straight lines u and t is too wide, new toner is brought to the developing sleeve 3 by the supply roller 5, passes through the elastic blade 4 as it is, and stays in the vicinity of the elastic blade. However, the old toner that has passed through the blade is replaced with new toner, and the advantage of preventing toner deterioration is lost. Further, as the supply roller rotates, the toner that rushes into the blade abutting portion disappears, and a sufficient coating amount of the sleeve may not be obtained.

The graph of FIG. 3 shows that the most upstream point P and the free end point Q of the contact surface side of the blade 4 when the sleeve rotation direction is the forward direction in the contact portion of the blade 4 and the sleeve 3 used in the first embodiment. On the sleeve with respect to the degree of toner aggregation in the region surrounded by the vertical line L passing through the free end point Q on the contact surface side of the blade 4 and the peripheral surface of the sleeve 3 (hatched portion in FIG. 4). The amount of coat per area.

The cohesion degree is set differently by using a toner after durable use, a toner that has absorbed moisture, and the like. Several plots have different blade-to-sleeve contact pressures.

The toner cohesion is measured with a powder tester PT-E manufactured by Hosokawa Micron. Further, regarding the sampling of the toner for measurement, since the shaded area in FIG. 4 is slightly insufficient, a distance of 5 mm in the vicinity of this area, on the upstream side of the blade from the blade free end and near the sleeve.
It was decided to use it by limiting it to the area below. The measurement conditions are as follows.

Measurement conditions: 1. Set the mesh on the shaking table in the following order. Upper 100 mesh Opening 150 μm Medium 200 mesh Opening 75 μm Lower 400 mesh Opening 38 μm 2. Vibration width 0.4 mm 3. Vibration frequency 50 Hz (3000 pvm) 4. Toner 5 g / time 5. Vibration time 15 seconds 6. Cohesion degree = (toner weight on 100 mesh / 5 g) × 100 + (toner weight on 200 mesh / 5 g) × 100 × 0.6 + (toner weight on 400 mesh / 5 g) × 100 × 0.2

According to the results shown in FIG. 3, when the setting of the blade contact pressure is low, M / S takes a large value as the cohesion degree increases. Further, when the contact pressure is increased to some extent, the M / S tends to decrease when the aggregation degree is 30 to 40% or more. However, if the contact pressure is 5 to 30 (g / cm), as long as the cohesion degree changes within the range of 10 to 40%, an appropriate M / S, 0.35 to 0.55 (mg / cm) is obtained. c
m ² ) can be maintained.

The reason why the toner exhibits such characteristics is considered as follows. The toner in the cohesion degree measurement region (hatched portion in FIG. 4) is a toner that directly affects the coating state on the sleeve. For example, when the cohesion degree in this region is high and the frictional force between the sleeve and the toner is sufficiently large, a force that pushes up the elastic blade acts as the sleeve rotates, increasing the coating amount. When the friction amount between the sleeve and the toner is low, the agglomerated toner cannot obtain the force of advancing in the traveling direction against the pressing force of the blade and is not applied to the sleeve. When the cohesion is low, the toner layer in this area is divided by the pressing force of the blade and the conveying force of the sleeve, so that the sleeve coating amount is reduced. Of course, even if the cohesion is the same, the situation changes depending on the pressing of the blade. That is, there is a relationship between the proper degree of aggregation and the pressing of the blade.

The average particle size of 4 to 12 μm which is usually used at present
The degree of aggregation of the non-magnetic one-component toner tends to be higher than the set value according to long-term durability or depending on the environment. If the target value at the time of production is about 10% under normal temperature and normal humidity environment, it will be less than that. This phenomenon is hardly seen. Therefore, when the toner cohesion is set within the range of 10 to 40%, it is basically necessary to prevent the cohesion from becoming higher than 40%. In this case, without directly controlling the cohesion degree of the area shown in FIG. 4, the cohesion degree of the toner area (sleeves and the vicinity of the supply roller) entering this area can be maintained within this range in a short time. It's ok, but it's still good enough.

The toner supply roller is made of silicon single-foam foam. As long as the cohesion degree is maintained in a region not exceeding 40%, the toner gradually gets inside the roller as the developing operation is repeated many times. However, there was no inconvenience that the rollers became harder and hardened.

In the case of the supply roller having the continuous foaming property, even if the cohesion degree is appropriately maintained, there is a disadvantage that the roller is hardened. Is effective for stabilizing the image quality in long-term durability.

The developing electric field has an appropriate M / S, 0.3.
A proper value exists while maintaining 5 to 0.55 (mg / cm ² ).

In order to form a high-quality image while maintaining the proper M / S and toner cohesion as described above, there are more effective developing bias waveforms and frequencies, and ranges of electric field strength.

When a thin layer of non-magnetic toner is coated with an elastic blade, the average charge amount per unit weight is high, but on the other hand, there is a toner having a wide charge distribution and being charged in the opposite polarity. Such toner flies to the drum side due to the bias on the pullback side of the alternating electric field for development, adheres to the non-image portion, and becomes fog. Therefore, as shown in FIG. 5, a bias waveform is used in which the peak value for returning the toner from the drum to the sleeve side is smaller than the peak value for the side to be moved to the drum side. As the pull-back bias is smaller, the adhesion of the toner charged in the opposite polarity to the non-image portion is reduced while giving a sufficient electric field strength to the fly side.

Even if the amplitude of the alternating electric field is too small, sufficient development contrast cannot be obtained and the density is low. Further, even if the amplitude is too large, highly charged toner easily flies, and as a result, the latent image is formed by only a few highly charged toner that flies once on the drum and is not pulled back even by the pullback component of the alternating electric field in the sleeve direction. There is a possibility that the toner is filled with the toner, the development contrast is lost, the low-charged toner is not developed, and the density is lowered.

If the frequency is too low, the toner drum,
The reciprocating motion between the sleeves is reduced, a sharp image gradually formed due to the reciprocating motion cannot be obtained, and toner of low charge, which does not follow easily, adheres to the non-image portion, which may cause fog.

When the chargeability of the toner is high, at the proper frequency, due to the kinetic energy of the toner that first flies and reciprocates in the developing area, the original mirror image force is higher than the electric field strength and remains high on the sleeve. It is thought that the charged toner will be peeled off and fly, and the density can be obtained.However, since the reciprocating motion of the toner is weakened due to the low frequency, the highly charged toner does not fly and the density can be obtained. Fall into the situation of not having. Even if the frequency is too high, a dull low-charged toner cannot follow and the density cannot be obtained.

According to a study by the inventors, the maximum developing alternating electric field is 4.0 × 10 ⁶ (v / m) or more and 5.4 × 10 ⁶ (v
/ M) or less, and the frequency of the alternating electric field is 1.
It has been found that it is desirable that the frequency is 0 kHz or more and 8.0 kHz or less.

The chargeability of the toner is also considered to be a factor that influences the coat state from the viewpoint of the mirror image power on the sleeve, but the toner used for the measurement was measured by the two-component mesh method using the iron powder carrier in the charge amount measurement. 15-28μ
Toner within the range of C / g is used. The length from the blade contact point to the blade end is stable at 2 mm ±
It is 0.2 mm.

Example 1 Example 1 according to the present invention will be described below with reference to FIG. FIG. 7 is an explanatory view showing a characteristic part of the present invention.

Toner: Binder resin Styrene acrylic external additive Hydrophobized silica 1.2 parts by weight PVdF 0.5 parts by weight Average particle size 9.5 μm Blade: Material Silicon rubber SUS backing thickness 0.5 mm Including SUS plate Tangential pressure Extraction force measurement 15 (g / cm) (20μm thickness, Rz1.0μm SUS plate folded in two and inserted into the abutting part, insert the same SUS plate into the two gaps, and pull out the force. Length from this contact to the end 2.0 mm (distance between PQ in Fig. 7) Development electric field: Amplitude 4.8 (V / m) Peak value ratio on the fly side and pull back side 13: 7 Frequency 2. 0 kHz

With such a construction, the toner remaining amount was maintained at a constant amount while the toner was replenished successively, and an image output durability test of 100,000 sheets was conducted. When the power source of the image forming apparatus main body is turned on, a mechanism for rotating the developing sleeve and the supply roller for 15 seconds is provided before the image forming operation is started, and the agglomerated toner is agitated in a standing state for a long time.

As a result, a stable toner coating was maintained on the sleeve during the image formation of 100,000 sheets.
A good image was obtained. In the graph of FIG. 8, M of this embodiment is shown.
/ S and agglomeration of toner are shown with time. Even if the number of durable sheets increases, the MS is maintained at 0.4 to 0.5,
Also, the degree of aggregation is maintained at 20 to 30%.

Second Embodiment A second embodiment according to the present invention will be described below with reference to FIG. FIG. 9 is a block diagram of this embodiment. In the contact portion of the blade and the sleeve, the vertical line passing through the most upstream point with respect to the sleeve rotation direction is 1, and of the vertical lines contacting the toner supply roller, the vertical line farthest from the developing area of the developer carrying member is indicated by m. Has been done.

A toner stirring member 30 is arranged above the supply roller 5 and rotates in the direction of the arrow in conjunction with the rotation of the sleeve 3. The central axis position is right above the center of the supply roller 5. Other conditions are as follows.

Toner: Binder resin Polyester (negative toner) External additive Hydrophobic treated silica 0.5 parts by weight Average particle size 8.5 μm Blade: Material Silicon rubber (dry treated silica dispersion) SUS backing thickness 0.5 mm SUS plate included Pair Sleeve contact line pressure Pulling force measurement 20 (g / cm) (20μm thickness, Rz1.0μm SUS plate folded in two and inserted into the contact part, insert the same SUS plate into the two gaps and pull it out Length from this contact to the end 2.3 mm (distance between PQ in Fig. 9) Development electric field: Amplitude 4.4 (V / m) Frequency 2.0 kHz

With such a structure, the toner remaining amount was maintained at a constant amount while the toner was replenished successively, and an image output durability test of 100,000 sheets was conducted.

As a result, a stable toner coating was maintained from the beginning on the sleeve while 100,000 sheets of images were being output, and a high-quality image was obtained. In the graph of FIG. 10, M of the present embodiment is shown.
/ S and agglomeration of toner are shown with time. Both the M / S and the toner cohesion are maintained within the proper ranges.

Further, as a comparative experiment, as shown in FIG. 11, the same 100,000-image endurance test was conducted with a developing device configuration in which a stirring member was arranged at a position 10 mm away from the vertical line m in the direction opposite to the sleeve. . The graph of FIG. 12 shows M of this embodiment.
/ S and agglomeration of toner are shown with time. The stirring part
Since it is not in the proper position, the area that originally needs to be stirred is not stirred, and after standing for a long time, the toner agglomeration degree is high near the blade contact portion, and M / S is not stable. Similar results were obtained even when the shape of the member was changed or in the configuration in which the rotating shaft of the stirring member was disposed closer to the elastic blade fixing position than the straight line l.

Example 3 Hereinafter, Example 3 of the present invention will be described. The structure of the developing device in this embodiment is the same as that shown in FIG. The conditions are as follows.

Toner: Binder resin Styrene acrylic external additive Dry-processed silica 2.2 parts by weight PVdF 0.5 parts by weight Average particle size 8.5 μm Blade: Material Urethane rubber SUS backing thickness 1.0 mm vs. sleeve contact line pressure drawing Force measurement 30 (g / cm) (20μm thick, Rz1.0μm SUS plate folded in two and inserted into the contact area, insert the same SUS plate into the two gaps, and convert it from the pulling force) Length from this contact to the end 2.6 mm (distance between PQ in Fig. 3) Development electric field: Amplitude 5.0 (V / m) Peak value ratio on the skipping side and pulling side 2: 1 Frequency 1.8 kHz

With such a structure, while the toner was successively replenished, the remaining amount of the toner was maintained at a constant amount, and the durability test of 100,000 images was carried out. As a result, a stable toner coating was maintained from the beginning on the sleeve during the image formation of 100,000 sheets, and a high-quality image was obtained. The graph of FIG. 13 shows changes with time of the M / S and the toner aggregation degree in this example.

In this embodiment, the amount of silica externally added to the toner is large, and the degree of aggregation is considerably low in the initial stage. As the images were printed, the degree of cohesion increased to some extent, but it was maintained below 40% up to 100,000 sheets.

[0062]

As is apparent from the above description, in the image forming apparatus according to the present invention, the most upstream point in the rotating direction of the developer carrying member and the developer in the contact portion between the elastic regulating member and the developer carrying member. The angle formed by the straight line passing through the center of the carrying member, the straight line passing through the center point of the contact portion between the developer supplying means and the developer carrying member, and the center of the developer carrying member is 5
A straight line which is 0 degree or more and 80 degrees or less and which passes through the most upstream point in the contact direction between the elastic restriction member and the developer carrying member and the free end point of the elastic restriction member contact surface in the rotation direction of the developer carrying member. , The degree of cohesion of the developer in the area surrounded by the vertical line passing through the free end point of the elastic regulation member contact surface and the peripheral surface of the developer carrying member is always 10% or more and 40% or less, Since the linear pressure between the elastic regulation member and the contact portion of the developer carrying member is 5 (g / cm) or more and 30 (g / cm) or less, the amount of developer on the developer carrying member can be kept constant. Therefore, when used for a long time, it is possible to prevent image deterioration such as image density change and fog, and obtain a stable and good image.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a developing device according to the present invention.

FIG. 2 is an explanatory view of a main part of the developing device of FIG.

3 is a graph showing toner cohesion degree characteristics in the developing device of FIG. 1. FIG.

FIG. 4 is an explanatory diagram showing a region where a proper toner aggregation degree is to be set.

FIG. 5 is an explanatory diagram showing an example of an applied developing bias.

FIG. 6 is a configuration diagram showing an example of an image forming apparatus in which the present invention is embodied.

FIG. 7 is an explanatory diagram illustrating a main part of the developing device according to the first exemplary embodiment.

FIG. 8 is a graph showing a result of a durability test of Example 1.

FIG. 9 is an explanatory diagram illustrating a main part of a developing device according to a second embodiment.

FIG. 10 is a graph showing a result of a durability test of Example 2.

FIG. 11 is an explanatory diagram showing a comparative example of the developing device of Example 2.

FIG. 12 is a graph showing the results of a durability test of the comparative example of FIG.

13 is a graph showing the results of the durability test of Example 3. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum (latent image bearing member) 3 Developing sleeve (developer carrying member) 4 Elastic blade (elasticity regulating member) 5 Supply roller (developer supplying means) 6 Toner (developer) 7, 8 Stirring member 20 Developing device 30 Stirrer

Claims (7)

[Claims] 1. A rotatable developer carrying member for carrying and transporting a non-magnetic one-component developer contained in a developer containing container to a developing section, and a rotary member provided in contact with the developer carrying member. A possible developer supply means, and an elastic restriction member that abuts on the downstream side of the developer supply means in the rotation direction of the developer carrying member to restrict the amount of developer applied to the developer carrying member,
An image forming apparatus having a developing device for performing non-contact development by forming an alternating electric field in a gap between the latent image carrier that forms the developing unit and the developer carrier. A straight line passing through the most upstream point in the rotation direction of the developer carrying member and the center of the developer carrying member in the abutting part of the developer carrying member, and the abutting part of the developer supplying means and the developer carrying member. The angle between the center point and a straight line passing through the center of the developer carrying member is 50 degrees or more and 80 degrees or more.
And a straight line passing through a free end point of the elastic regulating member contact surface in the contact portion of the elastic regulating member and the developer supporting member in the rotation direction of the developer supporting member and the elastic regulating member. The degree of cohesion of the developer in the area surrounded by the vertical line passing through the free end point of the member contact surface and the peripheral surface of the developer carrying member is always 10% or more and 40% or less,
An image forming apparatus, wherein a linear pressure between the elastic regulation member and the developer carrying member contact portion is 5 (g / cm) or more and 30 (g / cm) or less. 2. The peak value on the side where the alternating electric field formed in the gap between the latent image bearing member and the developer bearing member moves the developer toward the latent image bearing member is the latent image of the developer. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus has a bias waveform larger than a peak value of pulling back from the carrier to the developer carrying member side. 3. The maximum electric field of the alternating electric field formed in the gap between the latent image carrier and the developer carrying member is 4.0 × 1.
The image forming apparatus according to claim 1, wherein the image forming apparatus has a size of 0 ⁶ (v / m) or more and 5.4 × 10 ⁶ (v / m) or less. 4. The image forming apparatus according to claim 1, wherein the frequency of the alternating electric field is 1.0 kHz or more and 8.0 kHz or less. 5. The image forming apparatus according to claim 1, wherein the developer supply unit is made of a foam having a single foam structure. 6. A developer agitating member, wherein a central axis of the developer agitating member is the most upstream in a contact portion between the developer carrying member and the elastic regulating member with respect to a rotating direction of the developer carrying member. A vertical line that passes through a point and a vertical line that is in contact with the developer supply unit and is arranged between the vertical line that is farthest from the developing portion of the developer carrying member, and is in the same direction as the developer carrying member. The image forming apparatus according to claim 1, wherein the image forming apparatus rotates. 7. The control mechanism for driving the developer carrying member and the developer supplying means after the power supply of the image forming apparatus main body is turned on and before the image forming operation is started. Image forming apparatus.