JPH08185044A - Development device - Google Patents

Abstract

(57) [Summary] [Object] A developing device such as a copying machine using an electrophotographic system, in which a uniform charge and a uniform layer formation of the developer are carried out on a developer carrier by a simple method, and fogging by the development is performed. The purpose is to stably obtain a high-quality image with no uneven density. In a developing device in which a developer layer restriction member is brought into contact with a developer carrying member to form a developer layer on the developer carrying member for development, the developer layer restricting member is in direct contact with the developer carrying member. A regulating portion layer made of an elastic member having a surface, a joining portion layer made of one or more joining members, and a supporting portion layer made of a supporting member for holding them are provided. The pressure is applied to the developer carrier with an arbitrary nip width, and the hardness of the vicinity of the nip portion of the contact portion with the developer carrier and the hardness of other parts are different.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device such as a copying machine, a printer or a facsimile which utilizes an electrophotographic system, and in particular, a developing device which forms a uniform developer layer on a developer carrier. The present invention relates to a developing device using a component developer.

[0002]

2. Description of the Related Art Generally, a developing device of a one-component developing system forms a thin layer of a charged one-component developer on a developer carrier whose surface is movable, and deposits the thin layer of the charged one-component developer. The latent image carrier is conveyed to a region facing the latent image carrier to be developed.
At this time, the thin layer of the charged one-component developer is formed by pressing the developer layer regulating member against the developer carrier to regulate the layer thickness of the one-component developer layer on the developer carrier and charging it. Is done by doing.

FIG. 11 is a schematic sectional view of a conventional developing device using a one-component developer. This developing device includes a casing 10, and a toner hopper 11 of the casing 10 stores a toner 12 which is a one-component developer. The toner 12 is applied and carried on a developing roller 14 which is a developer carrying member by a toner supplying roller 13 which is a developer supplying member installed on the bottom surface of the toner hopper 11, and further contacts a developing layer 14 which is a developer layer regulating member 15. It is formed into a thin layer on the developing roller 14 by being charged and regulated by the layer.

The toner 12 formed as a thin layer on the developing roller 14 rotates counterclockwise in the figure and is conveyed to a developing area facing the photosensitive drum 16 which is a latent image carrier. Then, the toner 12 adheres to the photosensitive drum 16 by the electrostatic force by the action of the electric field generated by the latent image itself on the photosensitive drum 16 or a bias electric field (not shown), and development is performed. The toner 12 not attached adheres to the toner supply roller 13 that rotates in the same direction as the developing roller 14.
Then, the toner is scraped off from the developing roller 14, returns to the inside of the toner hopper 11, and is coated again on the developing roller 14 together with the new toner 12 in the toner hopper 11.

The developer layer regulating member 15 is composed of a blade 15a which is a regulating portion layer made of an elastic member which comes into direct contact with the developing roller 14 and a blade holder 15b which is a supporting portion layer made of a rigid member which holds the blade 15a. It is configured. The developer layer regulating member 15 is the blade pressing mechanism 1
Although it is pressed against the developing roller 14 with an appropriate pressure by 7, as shown in FIG.
The blade 15a may be pressed by the elastic force of itself.

[0006]

In the conventional developing device using the one-component developing method, in order to stably obtain a uniform and sufficient density and high quality image without fog, the developing roller 14 is uniformly charged. It is necessary to stably form a thin layer of toner 12. The state of charging and layer formation of the toner 12 is related to the contact state between the blade 15a and the developing roller 14, and in order to make the both uniform, the contact state between the blade 15a and the developing roller 14 over the entire width of the developing roller 14 is required. It is necessary to make it uniform at all times.

However, the blade 15a and the developing roller 14
Is pressed against the surface of the developing roller 14 with an arbitrary nip width, and the contact time between the blade 15a and the toner layer is the time during which the surface of the developing roller 14 moves along the nip width, which is extremely short. There is an inconvenience that it is difficult to perform sufficient charging.

Further, when the surface of the developing roller 14 moves the nip width due to unevenness such as waviness on the surface of the blade 15a, eccentricity of the developing roller 14, or unintentional unevenness of the surface, the developing roller 14 and the blade 15a are separated from each other. There is an inconvenience that the contact state becomes unstable and is not uniform. These disadvantages become more remarkable as the moving speed of the surface of the developing roller 14 becomes faster.

To overcome these disadvantages, the blade pressing mechanism 17 or the like increases the blade pressing force to perform sufficient charging to remove the effects of the unevenness of the surface of the blade holder 15b and the unevenness of the surface of the developing roller 14 to some extent. The charging of 12 and the uniformization of layer formation can be achieved. But,
In this case, the torque required to drive the developing roller 14 to rotate increases, the toner 12 is likely to aggregate at the pressure contact portion, and further the toner 12 is fused to the blade 15a, resulting in the toner layer. New inconveniences such as the occurrence of uneven streaks occur.

As for the latter disadvantage, the blade 15a is made thicker or is made of a material having a lower hardness.
5a is used to soften the contact area to absorb the unevenness of the surface of the blade 15a, the eccentricity of the developing roller 14, and the effects of the unevenness of the surface in the thickness direction of the blade 15a, and to provide a stable and uniform contact state. Can be realized.

However, when the blade 15a is thickened, the effect of reducing the hardness due to the increase in thickness is small, and there is a limit to the reduction. That is, if the hardness is lowered to a required degree, the blade 15a becomes too thick. Alternatively, no matter how thick it is, it cannot be reduced to the required hardness.

On the other hand, if the hardness of the blade 15a is lowered by changing the material of the blade 15a, the following problems occur. Abrasion resistance and durability deteriorate. When joining with the blade holder 15b, sticking unevenness is likely to occur, and as a result, a uniform contact cannot be made and a uniform layer cannot be formed. It is difficult to form the blade 15a itself having a low hardness and uniform, and the components that make up the blade 15a start to melt, and conversely, contamination of the blade 15a from the outside easily occurs.

Therefore, according to the present invention, uniform charging of the developer and formation of a uniform layer are carried out on the developer carrier by a simple method, and a high-quality image free from fogging and uneven density due to development is stably provided. It is an object to provide a developing device to be obtained.

[0014]

A first aspect of the present invention is a developing device for forming a developer layer on a developer carrying member by bringing a developer layer regulating member into contact with the developer carrying member for developing. The layer restricting member is composed of a restricting portion layer made of an elastic member having a surface that directly contacts the developer carrying member, a joining portion layer made of one or more joining members, and a supporting portion layer made of a supporting member holding these. The pressure contact with the developer carrier with an arbitrary nip width on the surface in contact with the developer carrier, and the hardness in the vicinity of the nip part of the contact part with the developer carrier and other parts are different. Is.

In a second aspect based on the first aspect, the regulating portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is elastic. It is adhered and fixed to the support part layer through the joint part layer consisting of the joint member that has this fixation, in the joint part layer, in the vicinity of the back side of the nip part of the regulation part layer, without using the joint member Is.

According to a third aspect of the present invention, in the first aspect, the restriction portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is elastic. It is adhered and fixed to the support layer through a joint layer made of a joint member that has this fixation. The hardness is different.

According to a fourth aspect of the present invention, in the third aspect of the invention, in fixing, the hardness of the joining member in the portion near the back side of the nip portion of the regulating portion layer in the joining portion layer is made softer than the hardness of the joining members in other portions. It is a thing.

In a fifth aspect based on the first aspect, the regulating portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is elastic. It is adhesively fixed to the support part layer through the joining part layer consisting of the joining member that has this fixing, and this fixing is performed by the thickness of the joining member in the vicinity of the back side of the nip part of the regulating part layer and the joining member in other parts. The thickness is different.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the fixing is such that the thickness of the joining member in the vicinity of the back side of the nip portion of the regulating portion layer in the joining portion layer is smaller than the thickness of the joining members in the other portions. It is a thing.

In the first to sixth inventions, as the member that specifically constitutes the developer layer restricting member, an elastic member such as natural rubber, urethane rubber, or silicon rubber is used as the restricting portion layer. Further, to these rubbers or the like, a charge imparting substance or the like for more effectively charging the developer is added, or various substances are added in order to obtain desired physical properties such as hardness and electrical characteristics. May be.

As the support layer, a member having rigidity such as metal such as aluminum is used. Further, as the bonding layer, for example, a bonding member having elasticity and thickness such as an adhesive or double-sided tape using sponge foam as a base material which has elasticity even after curing is used.

A regulating portion layer made of a plate-shaped member is bonded and fixed to a support portion layer made of a plate-shaped member via a joining layer made of one or more kinds of members. The joining member used for the portion near the back side of the nip portion of the regulation portion layer that is in pressure contact with the developer bearing member is different from the joining member used for the other portions.

Assuming that the regulating portion layer is pressed against the developer carrying member at the substantially central portion of the plate width, in the second invention, the central portion in the width direction of the regulating portion layer floats from the supporting portion layer. The both ends in the width direction are fixed to the support layer by the joining members.

In the third and fourth inventions, the joining member for fixing the widthwise central portion of the regulating portion layer to the supporting portion layer and the joining member for fixing both widthwise end portions of the regulating portion layer to the supporting portion layer. In the fourth aspect of the invention, the joining members for fixing the widthwise central portion of the regulation portion layer to the support portion layer are fixed to both ends of the regulation portion layer in the width direction to the support portion layer. It should be softer than the joining member.

In the fifth and sixth inventions, a joining member for fixing the widthwise central portion of the regulating portion layer to the supporting portion layer and a joining member for fixing both widthwise end portions of the regulating portion layer to the supporting portion layer. In the sixth aspect of the invention, particularly, in the sixth aspect of the invention, the joining member for fixing the central portion in the width direction of the restriction portion layer to the support portion layer is fixed to both ends of the restriction portion layer in the width direction to the support portion layer. It should be thinner than the joining member.

[0026]

In general, the hardness of the elastic member is defined as hardness, and is a physical property value that is uniquely determined if the material, composition, etc. of the elastic member are determined and the measuring method is determined. However, even with the same elastic member, if the thickness and the member behind the elastic member are different, the hardness felt by a person in contact with the elastic member is different.

For example, the same elastic members having different thicknesses, that is, an elastic member having an extremely thin thickness and an elastic member having a certain amount of thickness are placed on a steel plate having no elasticity, and appropriate members are brought into contact with each other and pressed against each other. When the hardness is examined, the presence of the elastic member is hardly felt in the extremely thin one, and the hardness as if the steel plate is directly pressed is felt. On the other hand, the presence of the elastic member is felt in the elastic member that is thick to some extent, and the hardness is felt to some extent.

In other words, when the back steel plate is regarded as one member, the extremely thin elastic member is apparently harder in hardness than the elastic member which is thick to some extent. Or, even if the same elastic member with the same thickness is used, if the hardness is examined in the same manner when placed on a steel plate that does not have elasticity and when placed on a rubber plate that has elasticity, Since the elasticity of the rubber plate is added to the one placed on the rubber plate, the hardness is apparently lower than that on the steel plate. In this application, the apparent hardness when it is regarded as one member as a whole is called "apparent hardness".

When the individual charging of the developer particles is viewed from a microscopic viewpoint, the individual charging of the developer particles is caused by the contact between the developer particles and the surface of the developer carrying member and the surface of the regulation layer of the developer layer regulating member. Caused by the interaction of. At this time, the contact of the developer layer restriction member with the surface of the restriction layer is largely related to the composition of the surface of the restriction layer, and the composition of the restriction layer of the developer layer restriction member is set to a desired charge of the developer particles. A suitable composition is desired.

On the other hand, when the charging and layer formation of the developer are viewed from a macroscopic viewpoint, the charging and layer formation of the developer are performed by the restriction layer of the developer layer restriction member and the developer carrier (including the developer layer). Regardless of the state of contact, in order to form a thin developer layer having a uniform charge and a uniform layer thickness, the regulating layer of the developer layer regulating member and the developer carrying member must be in uniform contact over the entire width. This uniform contact can be achieved by reducing the apparent hardness of the regulating layer of the developer layer regulating member, as described later.

According to the first aspect of the invention, the hardness of the vicinity of the nip portion in contact with the developer carrying member of the regulation layer of the developer layer regulating member and the hardness of other portions are different.
That is, the composition itself of the regulation layer of the developer layer regulating member is a composition suitable for the desired charging of the developer particles and raises the charging efficiency of the developer particles. By lowering the hardness of the portion of the partial layer near the nip portion, it is possible to make uniform contact with the developer carrying member in the nip portion.

That is, since the regulating portion layer of the developer layer regulating member and the developer carrying member are in contact with each other with low hardness at the nip portion, the nip portion of the regulating portion layer of the developer layer regulating member pushes against the developer carrying member. The amount of deformation (dent) increases and the nip width becomes wider. Since the restriction portion layer of the developer layer restriction member is pressed and deformed by the developer carrying member, it is deformed along the peripheral surface of the developer carrying member and has good adhesion.

Further, since the regulation layer of the developer layer regulating member is low in hardness, the peripheral surface of the developer carrying body is displaced due to eccentricity of the developer carrying body or the like, and the unevenness on the surface of the developer carrying body is unintentional. It is possible to follow the eccentricity, the displacement, and the like and absorb the influence of the dynamic displacement. Similarly, the effect of unevenness of the joint surface of the support layer of the developer layer regulating member with the regulation layer of the developer layer regulating member, undulation, or undulation of the regulation layer itself of the developer layer regulating member is also absorbed. be able to.

As a result, the contact between the developer carrying member and the regulation layer of the developer layer regulating member can be made stable and uniform. At this time, even if the pressure applied to the regulation layer of the developer layer regulation member is the same, the nip width is expanded due to the lower hardness, so the pressure at the nip is reduced. That is, even with the same pressing force, the contact nip width between the regulation portion layer of the developer layer regulating member and the developer carrying member is widened, the adhesion is also increased, and charging and layer formation are improved. On the other hand, since the contact pressure at the nip portion is reduced, it is possible to prevent the developer from aggregating due to the pressure applied to the regulation layer of the developer layer regulating member.

These effects are obtained by lowering the hardness of the portion near the nip portion, and it is not necessary that the hardness of the portion other than the portion near the nip portion be the same. By making the hardness of the portion other than the portion near the nip portion different from the hardness of the portion near the nip portion, the regulating portion layer of the developer layer regulating member is provided with an apparent hardness distribution, and It can be brought into contact with the carrier. Deformability is different depending on the apparent hardness distribution, and the adhesiveness can be adjusted when the developer comes into contact with the developer carrier.

That is, when the hardness of the portion other than the portion near the nip portion is made higher than the hardness of the portion near the nip portion, both sides of the nip width are less likely to be deformed, and the developer carrying member is pushed back at this portion. Power becomes stronger. Therefore, high adhesion can be obtained up to the end of the nip width. On the contrary, if the hardness of the parts other than the part near the nip part is set lower than the hardness of the part near the nip part, the force to push back on both sides of the nip width is weak, so the adhesion at the end of the nip width is reduced. Can be lowered.

Further, these effects are caused by the lower hardness of the vicinity of the nip portion of the regulating layer of the developer layer regulating member, and the developer carrying on the surface of the regulating layer of the developer layer regulating member. A slight difference in the contact angle to the body, a slight difference in the nip position of the regulation layer of the developer layer regulation member, and the like have very little effect on the contact state. That is, it is possible to obtain a stable and uniform contact without increasing the mounting accuracy of the restriction layer of the developer layer restriction member and even if the contact angle, the nip position, or the like changes slightly with time.

In the second to sixth inventions, more specifically, the apparent hardness of the portion near the nip portion of the regulating layer of the developer layer regulating member is different from the apparent hardness of the other portion. For example, by fixing the regulating portion layer of the plate-like elastic developer layer regulating member to the support portion layer of the developer layer regulating member via the elastic joining member, the regulating portion layer of the developer layer regulating member The apparent hardness is the hardness including the hardness of the joining member in addition to the hardness of the regulation layer itself of the developer layer regulating member.

That is, the apparent hardness as a whole can be made lower than the apparent hardness when the regulating layer of the developer layer regulating member is directly fixed to the supporting layer of the developer layer regulating member, and thus the developer layer regulating member. The pressure contact portion of the restriction portion layer with the developer carrier can be brought into contact with the developer carrier with a lower apparent hardness while maintaining the hardness of the restriction portion layer itself.

According to the second aspect of the invention, the joining member is not used in the vicinity of the back side of the nip portion of the regulating layer of the developer layer regulating member,
By forming the cavity, the apparent hardness of the portion near the nip portion is made lower than that in the case where the joining member is present in the neighboring portion. That is, the developer layer regulating member is configured so that the portion in the vicinity of the nip portion of the regulating portion layer is hollow and has a different hardness from the other portions.

In particular, in this case, even if there is unevenness on the surface of the support layer of the developer layer restriction member on the side to be joined to the restriction layer of the developer layer restriction member, the effect of the unevenness is through the cavity. Therefore, it is not on the contact surface side of the regulation layer of the developer layer regulation member with the developer carrying member. Further, there is no joining member in the vicinity of the immediate back side of the nip portion, but there is an joining member having elasticity in both sides thereof. In the restriction layer of the developer layer restriction member, only the nip portion that is in direct contact with the developer carrying member is not deformed (dented) to the side opposite to the contact surface with the developer carrying member when contacting the developer carrying member. Both sides of the nip portion are also deformed along with the deformation of the nip portion.

At this time, there is a deformation of the joining member having a sideward elasticity in the vicinity of the immediate back surface of the nip portion. In this case, the apparent hardness of the nip portion of the regulation layer of the developer layer regulation member is soft, and the amount of deformation (dent) is large at the time of contact with the developer carrying member. On the other hand, on both sides of the nip portion, since the joining member is present on the back surface, the apparent hardness is higher than that of the nip portion and it is difficult to deform. Therefore, the amount of deformation (dent) is small, but since the joining member is deformed, the developer The restoring force due to the elasticity of the regulating portion layer of the layer regulating member and the restoring force of the joining member are overlapped with each other and adhere to the developer carrying member.

That is, in the central portion of the nip, the amount of dent of the regulating layer of the developer layer regulating member is large, and the restoring force is large correspondingly, so that it closely adheres to the developer carrier, and at the end of the nip width, the developer layer regulating member Although the dent of the regulation layer itself is small, the restoring force of the joining member also overlaps and adheres to the developer carrying member. As a result, the adhesiveness between the restriction portion layer of the developer layer restriction member and the developer carrying member is further enhanced, and the developers are in uniform contact.

In the third and fourth aspects of the invention, the hardness of the joining member in the immediate rear side of the nip portion and the other portions are changed so that the vicinity of the nip portion of the regulating portion layer of the developer layer regulating member is changed. The apparent hardness of the part and the other part are different.

Particularly in the fourth aspect of the invention, the hardness of the joining member in the vicinity of the back side of the nip portion is made lower than that of the other portions,
The nip portion of the regulation layer of the developer layer regulation member is soft and easily deformed, and both sides thereof are not easily deformed. For this reason, the developer carrying member comes into contact with the regulation portion layer of the developer layer regulating member having a soft and easily deformable nip portion. That is, there is the same effect as in the case of the second invention.

Further, in this case, since the joining member also exists on the back surface of the nip portion, the restoring force of the joining member is applied to the developer carrying member under pressure and acts in the rotational direction accompanying the rotation of the developer carrying member. A large restoring force is generated even with respect to the shearing force, and the rigidity with respect to the deformation of the regulation portion layer is increased.

According to the fifth and sixth aspects of the invention, the thickness of the joining member in the vicinity of the back side of the nip portion and the thickness of the joining member in the other portions are changed so that the regulation layer of the developer layer regulating member is changed. The apparent hardness of the portion near the nip is different from that of the other portions. That is, in the thick portion of the joining member, the apparent hardness of the regulation layer of the developer layer regulating member is lower than that in the thin portion of the joining member.

Further, in this case, by changing the thickness of each portion, the contact shape between the regulating layer of the developer layer regulating member and the surface of the developer carrying member can be dimensionally changed. In particular, in the case of the sixth method, the surface shape of the contact surface of the regulation portion layer of the developer layer regulation member is preliminarily set by making the thickness of the joining member in the vicinity of the back side of the nip portion thinner than other portions. It can be shaped to conform to the surface shape of the developer carrier to some extent, and when contacting, the restriction layer of the developer layer restricting member itself and the joining member are deformed to adhere to the surface of the developer carrier and widen the nip width. It is possible to realize uniform layer formation.

[0049]

1 is a schematic cross-sectional view showing a first embodiment of a developing device according to the present invention, in which a blade 1 which is a regulating layer of a developer layer regulating member 15 and a blade holder 2 which is a supporting layer.
It shows the joined state with. Further, FIG. 2 shows a contact state between the developing roller 14 which is a developer bearing member and the developer layer regulating member 15.

The blade 1 of the developer layer regulating member 15 is fixed to the flat blade holder 2 by using the elastic joining member 3 which is a joining layer. The fixing is made in a hollow state without using the joining member 3 in the vicinity of the back side of the nip portion of the blade 1. When the blade 1 is fixed in this way, the apparent hardness at point B (the portion without the joining member 3 on the back surface) in FIG. 1 becomes lower than the apparent hardness at the point A (the portion with the joining member 3 on the back surface). .

Therefore, since the apparent hardness of the blade 1 is reduced near the nip portion, the nip width in contact with the developing roller 14 is widened and the developer can be sufficiently charged. Further, even if the surface of the blade holder 2 joined to the blade 1 or the surface of the developing roller 14 has minute unevenness, the influence of the unevenness can be easily absorbed. Further, the end of the nip width is pressed against the surface of the developing roller 14 due to the restoring force of the joining member 3 also overlapping, so that high adhesion can be obtained between the blade 1 and the developing roller 14 over the entire width of the nip.

As a result, the contact time between the developing roller 14 and the blade 1 can be made long and uniform, and the one-component developer can be uniformly charged on the developing roller 14 and regulated to a uniform layer thickness. That is, it is possible to stably form a thin developer layer having a uniform layer thickness that is uniformly charged on the developing roller 14.

A specific numerical example will be described. Made of aluminum, a rigid metal, length 300 mm, width 15 mm, thickness 5 mm
The double-sided tape having a thickness of about 0.6 mm and made of sponge foam as a base material is used as the joining member 3 in the flat blade holder 2 of No. 3, which is made of polyurethane rubber with JIS A hardness of about 65 degrees and has a length of 300 mm and a width of 15 mm. , A blade 1 having a thickness of 2 mm is fixedly held.

The portion directly behind the nip portion of the blade 1 has a width of about 5 mm and is in a hollow state without using the joining member 3. The hardness measurement value at points A and B by a JIS / A hardness meter with the blade held is about 75 degrees at point A,
It is about 60 degrees at point B. The developing roller 14 has a diameter of about 30 m.
The surface is sandblasted with an aluminum cylinder of m and length of about 300 mm. Further, the blade 1 is driven by a pressurizing mechanism (not shown) at a peripheral speed of about 17 at a linear pressure of about 100 g / cm.
It is pressed against the developing roller 14 which rotates at 5 mm / sec.

The developing roller 14 comes into contact with the blade 1 near the point B, but the hardness of the portion near the nip portion of the blade 1 is different from the hardness of other portions (near the point A), and further near the nip portion. The hardness of the part is lower. If the back surface is not hollow and is uniformly joined with double-sided tape, the blade 1 itself is a rubber having a JIS / A hardness of about 65 degrees, but has a thin thickness of about 2 mm. This is the same as contacting a blade having an apparent hardness of 75 degrees.

However, if the back surface is made hollow as in this embodiment, the blade 1 itself is a rubber having a JIS / A hardness of about 65 degrees, but when viewed from the developing roller 14, a portion near the upper nip portion (around the point B). ) Is about 60 degrees, which means that the outside of the vicinity (near point A) can be made to be in contact with the regulation layer having a hardness of about 75 degrees.

FIG. 3 shows the developing roller 1 after passing through the blade 1.
4A and 4B are views showing the results of measuring the distribution shape of the surface potential in the axial direction of FIG. 4, where FIG. 7A is a case where a cavity is provided on the back surface of the nip portion as in this embodiment, and FIG. This is the case where no cavity is provided in (Comparative Example). FIG. 4 shows each average value, standard deviation, maximum value, minimum value, etc. as a table.

As a result, in the case of this embodiment, the average surface potential is 11.4 V, the standard deviation is 1.6 V, and the maximum value is 17.3.
V, the minimum value is 10.3V. On the other hand, in the case of the comparative example,
The average value of the surface potential is 13.3V, the standard deviation is 2.1V, the maximum value is 17.1V, and the minimum value is 5.7V.

The homogeneity in the axial direction is examined by the ratio of the standard deviation to the average value (standard deviation / average value) and the ratio of the maximum / minimum difference to the average value ((maximum value-minimum value) / average value). In the present embodiment, the former is 0.11 and the latter is 0.
In the comparative example 50, the former was 0.15 and the latter was 0.86. If a completely uniform developer layer is obtained, the surface potential distribution should have constant values and these values should be zero. That is, the smaller these values are, the smaller the variation with respect to the average value and the better the uniformity. Therefore, it can be seen that this example forms a more uniform developer layer.

Next, a second embodiment of the present invention will be described. FIG. 5 is a schematic cross-sectional view showing a second embodiment of the developing device according to the present invention, in which the blade 1 which is the regulating portion layer of the developer layer regulating member 15 is joined to the planar blade holder 2 which is the supporting portion layer. Elastic joining members 3a and 3 which are partial layers
It is fixed using b.

For the fixing, the joining member 3b is used in the portion near the back side of the nip portion of the blade 1, and the joining member 3a is used in the other portions. Joining member 3a and joining member 3b
Have the same thickness but different hardness. When the blade 1 is fixed in this way, the apparent hardness of the point D (the portion of the joining member 3b on the back surface) and the apparent hardness of the point C (the portion of the joining member 3a on the back surface) in the figure of the blade 1 are different. Can be Furthermore, if the joining member 3b having a hardness lower than that of the joining member 3a is used, the apparent hardness at the point D can be made lower than the apparent hardness at the point C.

For example, a flat blade holder 2 and a blade 1 similar to those of the first embodiment have a thickness of about 1.1 mm, and a double-sided sponge-based tape having an Asuka C hardness of about 75 degrees is used as a joining member 3a. About 1.1 mm, Asuka C hardness about 55
The double-sided tape of sponge base material is used as the joining member 3b to be fixed and held. The joining member 3b is used for the portion having a width of about 5 mm directly behind the nip portion of the blade 1, and the joining member 3a is used for the other portions. JIS / A with blade held
The hardness measured by the hardness meter at points C and D is about 7 at point C.
It was 5 degrees and about 65 degrees at point D.

That is, since the apparent hardness of the blade 1 is reduced in the vicinity of the nip portion, the nip width in contact with the developing roller 14 is widened and the developer can be sufficiently charged. Further, even if the surface of the blade holder 2 joined to the blade 1 or the surface of the developing roller 14 has fine unevenness, the effect of the unevenness is easily absorbed. In addition, the end of the nip width is pressed against the surface of the developing roller 14 due to the restoring force of the joining member 3a, and the central portion of the nip width is also joined to the joining member 3b.
Therefore, high adhesion can be obtained between the blade 1 and the developing roller 14 over the entire width of the nip.

As a result, as in the first embodiment, the contact time between the developing roller 14 and the blade 1 can be made long and uniform,
The developer layer can be uniformly charged on the developing roller 14 and regulated to have a uniform layer thickness. In this case, since the entire blade 1 is joined to the blade holder 2, the blade 1
The overall joining strength to the blade holder 2 is stronger, a large restoring force is generated against the shearing force acting in the rotation direction accompanying the rotation of the developing roller 14, and the rigidity with respect to the deformation of the regulating portion layer is increased.

Next, a third embodiment of the present invention will be described. FIG. 6 is a schematic cross-sectional view showing a third embodiment of the developing device according to the present invention, in which the blade 1 which is the regulating layer of the developer layer regulating member 15 is joined to the planar blade holder 2 which is the supporting layer. Elastic joint members 3c and 3 which are partial layers
It is fixed using d. For the fixing, the joining member 3d is used in the portion near the back side of the nip portion of the blade 1, and the joining member 3c is used in the other portions. Joining member 3c
And the joining member 3d are made of the same base material but have different thicknesses, and the joining member 3d is thinner than 3c.

When the blade 1 is fixed in this manner, the apparent hardness of point F (the portion of the joining member 3d on the back surface) and the apparent hardness of the point E (the portion of the joining member 3c on the back surface) in the figure of the blade 1 are obtained. Can be different. In this case, the apparent hardness at point F is higher than that at point E.
As an example, a flat blade holder 2 and a blade 1 similar to those of the first embodiment are used as a joining member 3c with a double-sided tape of sponge base material having an Asuka C hardness of about 60 degrees and a thickness of about 1.6 mm. Joining member 3 with a thickness of about 0.8 mm
It is used as d and is fixedly held.

The joining member 3d is used for the portion having a width of about 5 mm directly on the back side of the nip portion of the blade 1, and the joining member 3c is used for the other portions. The hardness measured by the JIS / A hardness tester with the blade held at points E and F is about 66 degrees at E,
It was about 70 degrees at point F. That is, the apparent hardness of the blade 1 near the nip portion is higher than that of the other portions.

However, in the case of this embodiment, the blade 1
The shape of the surface of the developing roller 14 that is pressed against the developing roller 14
4 can be fitted along the peripheral surface of the developing roller 14 to some extent before contact with the blade 4, and the blade 1 and the joining members 3c, 3 at the time of contact.
Due to the deformation of d, a wide width can be pressed against the developing roller 14 along the peripheral surface, and as a result, the blade 1 contacts the developing roller 14 with a wide nip width, and the blade 1 and the joining member 3
Since there is a restoring force of c and 3d, it can be pressed with high adhesion and
As in the above example, the developer can be uniformly charged to form a uniform thin layer of the developer.

Further, in this case, since the entire blade 1 is joined to the blade holder 2 via the joining members 3c and 3d, the joining strength of the entire blade 1 to the blade holder 2 is stronger and the developing roller 14 A large restoring force is also generated with respect to the shear stress acting in the rotation direction due to the rotation, and the rigidity with respect to the deformation of the restriction layer increases.

Next, a fourth embodiment of the present invention will be described. FIG. 7 is a schematic cross-sectional view showing a fourth embodiment of the developing device according to the present invention, in which the blade 1 which is the regulating portion layer of the developer layer regulating member 15 is a plane which is the supporting portion layer of the developer layer regulating member 15. The blade holder 2 is fixed to the blade holder 2 using elastic joint members 3e and 3f which are joint layers of the developer layer regulating member 15.

For the fixing, the joining member 3f is used in the portion near the back side of the nip portion of the blade 1, and the joining member 3e is used in the other portions. Joining member 3e and joining member 3f
Have different hardness and thickness of the substrate. When the blade 1 is fixed in this manner, the apparent hardness of the blade 1 at the point H (the portion of the joining member 3f on the back surface) and the apparent hardness of the point G (the portion of the joining member 3e on the back surface) in the figure are different. can do.

By doing so, the apparent hardness can be positively changed while positively changing the shape of the contact surface of the blade 1 with the developing roller 14. As an example, a flat blade holder 2 and a blade 1 similar to those of the first embodiment are provided with a thickness of about 1.1 mm and an Asuka C hardness of about 75.
The sponge base double-sided tape as the joining member 3e,
A sponge-based double-sided tape having a thickness of about 0.8 mm and an Asuka C hardness of about 60 degrees is used as the joining member 3f to be fixed and held.

The joining member 3f is used for the portion having a width of about 5 mm directly behind the nip portion of the blade 1, and the joining member 3e is used for the other portions. The hardness measured at points G and H by a JIS / A hardness meter with the blade held is about 75 degrees at point G,
It was about 70 degrees at the H point. That is, the apparent hardness of the blade 1 decreases near the nip portion, and the blade 1
The shape of the surface of the developing roller 14 that is pressed against the developing roller 14
4 can be fitted along the peripheral surface of the developing roller 14 to a certain extent without contacting the blade 4, and at the time of contact, the blade 1 and the joining member 3
Due to the deformations e and 2f, the blade 1 and the developing roller 14 are in contact with each other with a wide nip width, and the adhesion is high. As in the first embodiment, the developer is uniformly charged and a uniform thin layer of the developer is formed. Can be formed.

In this case, since the entire blade 1 is joined to the blade holder 2, the joining strength of the entire blade 1 to the blade holder 2 is stronger, as in the second embodiment.
A large restoring force is also generated with respect to the shearing force acting in the rotation direction due to the rotation of the developing roller 14, and the rigidity with respect to the deformation of the regulation portion layer is increased.

Next explained is the fifth embodiment of the invention. FIG. 8 is a schematic cross-sectional view showing a fifth embodiment of the developing device according to the present invention, in which the blade 1 is fixed in a hollow state on the back side of the nip portion, and thin joining members 3g are used in the vicinity of both sides thereof. Furthermore, thick joining members 3h are used on both sides thereof.

FIG. 9 is a schematic cross-sectional view showing a sixth embodiment of the developing device according to the present invention, in which the fixing of the blade 1 is not divided into the vicinity of the back side of the nip portion and the other portions.
The joining members 3a, 3b, 3c ... Are divided into smaller parts and joined. By doing so, the apparent hardness distribution of the blade 1 can be made fine and smooth, the uniformity of contact with the developing roller 14 can be increased, and a more effective and uniform developer layer can be formed. Can be formed.

FIG. 10 is a schematic cross-sectional view showing a seventh embodiment of the developing device according to the present invention, which is a joining member near the back side of the nip portion of the blade 1 with respect to the moving direction of the surface of the developing roller 14. The hardness of the joining member 3a on the upstream side of 3b is different from the hardness of the joining member 3c on the downstream side. By doing so, the adhesiveness with the developing roller 14 can be changed between the upstream side and the downstream side of the nip width, and the developer supply amount to the nip portion (upstream side) and the discharge amount from the nip portion ( Downstream side) can be controlled.

[0078]

According to the first aspect of the present invention, by making the hardness of the vicinity of the nip portion of the regulating portion layer of the developer layer regulating member different from the hardness of other portions, the contact with the developer carrying member can be achieved. The condition can be optimized. In particular, by making the hardness of the portion near the nip portion lower than that of the other portions, the pressure contact between the regulation portion layer and the developer carrying member can be made more uniform and the nip width can be widened. As a result, it is possible to form a uniformly thin and uniform developer layer, and it is possible to obtain a high-quality image with sufficient density and sufficient fog by development.

According to the second aspect of the present invention, by joining the regulating portion layer of the developer layer regulating member and the supporting portion layer with a joint member having elasticity, only the regulating portion layer is contacted with the developer carrying member under pressure contact. The hardness of can be reduced. Furthermore, the apparent hardness of the portion near the nip portion can be reduced by forming a hollow state without using a joining member in the portion near the back side of the nip portion of the regulation portion layer.

Further, the apparent hardness of the nip portion can be made soft, and it is possible to make contact with the developing roller with a wide nip width. Further, the apparent hardness of the outside of the vicinity of the nip portion is higher than that of the vicinity of the nip portion, and the restoring force of the joining member is also overlapped, so that the developer carrier is brought into close contact with pressure. As a result, a uniformly thin and uniform developer layer can be formed, and high-quality development can be performed.

According to the third aspect of the present invention, the regulating portion layer of the developer layer regulating member and the supporting portion layer are joined by the joining member having elasticity, so that only the regulating portion layer is contacted during the pressure contact with the developer carrying member. The hardness of can be reduced. Furthermore, by making the hardness of the joining member in the portion near the back side of the nip portion of the regulation portion layer different from the hardness of the joining member in the other portion, the portion near the nip portion of the regulation portion layer and other portions The apparent hardness can be different.

That is, even if the shape and the hardness distribution of the regulating layer itself of the developer layer regulating member are not special, or the shape of the supporting layer is not special, it appears to the regulating layer. It can be brought into pressure contact with the developer carrying member while having a distribution of upper hardness. As a result, a uniformly thin and uniform developer layer can be formed, and high quality development can be performed.

According to the fourth aspect of the present invention, by joining the regulating portion layer of the developer layer regulating member and the supporting portion layer with a joint member having elasticity, the regulating portion layer of the developing agent regulating member can be pressed at the time of pressure contact with the developer carrying member. The apparent hardness can be reduced. Further, by making the hardness of the joining member in the vicinity of the back side of the nip portion of the regulation portion layer lower than the hardness of the joining members in the other portions, the apparent hardness of the portion in the vicinity of the nip portion of the regulation portion layer is The hardness can be lower than the apparent hardness of the part.

That is, even if the shape or the hardness distribution of the regulating layer itself of the developer layer regulating member is not made special or the shape of the supporting layer is not made special, it appears to the regulating layer. The developer can be pressed against the developer carrying member with a distribution of hardness such that the hardness of the upper nip portion is low. As a result, it is possible to press the regulation portion layer of the developer layer regulating member to the developer carrier with a wide nip width and high adhesion,
A uniformly thin uniform developer layer can be formed, and high-quality development can be performed.

According to the fifth aspect of the present invention, by joining the regulating portion layer of the developer layer regulating member and the supporting portion layer with a joint member having elasticity, only the regulating portion layer is contacted with the developer carrying member under pressure contact. The hardness of can be reduced. Furthermore, by making the hardness of the joining member in the portion near the back side of the nip portion of the regulation portion layer different from the thickness of the joining member in the other portion, the portion near the nip portion of the regulation portion layer and the other portion are different. The apparent hardness can be different.

Further, since the thickness of the joining member changes, the surface shape of the regulating portion layer can also be changed. That is, the apparent hardness of the developer layer regulating member is not apparent even if the shape of the regulating layer itself or the hardness distribution is not special or the shape of the supporting layer is not special. Can be provided and the surface shape can be changed to press the developer carrier. As a result, a uniformly thin and uniform developer layer can be formed, and high quality development can be performed.

According to the sixth aspect of the present invention, by joining the regulating portion layer of the developer layer regulating member and the supporting portion layer with a joint member having elasticity, the regulating portion layer of the developer layer regulating member is brought into pressure contact with the developer carrying member. The apparent hardness can be reduced. Further, by making the thickness of the joining member in the portion near the back side of the nip portion of the regulating portion layer thinner than the thickness of the joining member in the other portion, the apparent portion between the portion near the nip portion of the regulating portion layer and the other portion is reduced. By making the hardness different, the surface shape of the regulation layer can be made to conform to the shape of the peripheral surface of the developer carrier to some extent.

That is, even if the shape or the hardness distribution of the regulating layer itself of the developer layer regulating member is not special, or the shape of the supporting layer is not special, it is apparent to the regulating layer. It is possible to press-contact the developer carrier with a distribution of the upper hardness and a surface shape that conforms to the peripheral surface shape of the developer carrier to some extent. As a result, with a wide nip width,
Further, the regulation layer of the developer layer regulating member can be pressed against the developer carrier with high adhesion, and a uniform thin and uniformly charged developer layer can be formed, and high-quality development can be performed. it can.

As described above, the effects described above can be obtained by using the present invention. In terms of widening the nip width, the surface of the elastic member, which corresponds to the regulation portion layer in the present invention conventionally, is made to conform to the peripheral surface shape of the developer carrier, and this is pressed against the developer carrier. The member corresponding to the supporting portion layer referred to in the present application is a frame body having a U-shaped cross section, and the elastic member corresponding to the regulating portion layer referred to in the present application is stretched over, and the stretched portion is pressed against the developer carrier. Methods have also been proposed.

However, in these methods, special processing is required and the positional accuracy of the attachment with the developer carrying member is also required. According to the present invention, the joining layer is provided between the regulating layer and the supporting layer, and the hardness and thickness of the joining member are partially changed in the joining layer to positively increase the apparent hardness of the regulating layer. Has a hardness distribution, and due to the hardness distribution, it is pushed by the surface of the developer carrier during pressure contact with the developer carrier, deforms along the surface of the developer carrier, and has a wide nip width and high adhesion. Can be obtained without any special processing,
It is possible to adopt a configuration in which the mounting position accuracy is not required.

Therefore, the contact between the regulation layer of the developer layer regulating member and the developer carrying member is wide with a wide nip and high in adhesiveness.
The developer carrier can be made uniform in the entire axial direction, and a thin developer layer having a uniform layer pressure that is uniformly charged can be formed on the developer carrier, resulting in uneven density due to development. It is possible to stably obtain a high-quality image without fog.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a contact state between a developer layer regulating member shown in FIG. 1 and a developing roller.

FIG. 3 is a graph showing an example of measurement results of the surface potential distribution shape in the axial direction of the developing roller after passing the blade, where (a) is the case of using the first embodiment and (b) is the case of using the comparative example. Is.

FIG. 4 is a diagram showing measured values of hardness and surface potential in the measurement example shown in FIG.

FIG. 5 is a schematic sectional view showing a second embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a third embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a fourth embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a fifth embodiment of the present invention.

FIG. 9 is a schematic sectional view showing a sixth embodiment of the present invention.

FIG. 10 is a schematic sectional view showing a seventh embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view showing a configuration example of a conventional developing device.

FIG. 12 is a schematic sectional view showing an example of a conventional blade holding state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 blade 2 blade holder 3, 3a-3h joining member 12 toner 13 toner supply roller 14 developing roller 15 developer layer regulating member 16 photoconductor drum 17 blade pressing mechanism

Claims (6)

[Claims] 1. A developing device for contacting a developer layer regulating member to a developer carrying member to form a developer layer on the developer carrying member for development, wherein the developer layer regulating member is the developer. The developer carrying member comprises a regulating portion layer made of an elastic member having a surface in direct contact with the carrier, a joining portion layer made of one or more joining members, and a supporting portion layer made of a supporting member holding these members. It is characterized in that it is pressed against the developer carrier at an arbitrary nip width on the surface in contact with the body, and the hardness of the vicinity of the nip part of the contact part with the developer carrier and other parts are different. Developing device. 2. The joining portion, wherein the regulating portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is made of an elastic joining member. The support part layer is adhered and fixed via a layer, and this fixing is performed in a hollow state without using the bonding member in the vicinity of the back side of the nip part of the regulation part layer in the bonding part layer. The developing device according to claim 1. 3. The joining portion, wherein the regulating portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is made of an elastic joining member. The support member layer is adhesively fixed via a layer, and the fixing is performed by the hardness of the bonding member in the portion near the back side of the nip portion of the regulating portion layer and the hardness of the bonding member in other portions in the bonding portion layer. 2. The developing device according to claim 1, wherein the developing units are different from each other. 4. The fixing is characterized in that the hardness of the joining member in the vicinity of the back side of the nip portion of the regulation portion layer in the joining portion layer is made softer than the hardness of the joining member in other portions. The developing device according to claim 3. 5. The joining portion, wherein the regulation portion layer is made of a plate-like elastic member, one surface of which is pressed against the developer carrying member with an arbitrary nip width, and the other surface of which is made of an elastic joining member. A layer is adhered and fixed to the support portion layer, and the fixing is performed by the thickness of the joining member in the portion near the back side of the nip portion of the regulating portion layer in the joining portion layer and the thickness of the joining member in other portions. 2. The developing device according to claim 1, wherein the developing units are different from each other. 6. The fixing is characterized in that the thickness of the joining member in a portion of the joining portion layer in the vicinity of the back side of the nip portion of the regulation portion layer is thinner than the thickness of the joining member in other portions. The developing device according to claim 5.