JP2012103301A - Developer carrier and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably convey an appropriate amount of a developer for a long period of time when a developer containing a toner and a carrier is held and conveyed on an outer circumference face of a rotating developer carrier.SOLUTION: A concavo-convex pattern is formed on an outer circumference face of a developer carrier 12 that rotates while holding a developer D containing a toner and a carrier on the outer circumference face. The concavo-convex pattern is formed in such a manner that: peaks of projections 12a in the pattern are flattened; an average of an inclination angle θ, in the range 50 to 80% of a portion from the lowest point in a recess 12b to the peak of a projection in a downstream side along the rotation direction of the developer carrier, is controlled to the range from 5° to 24°; and relationships between an average particle diameter (r) of the carrier and the ten-point average roughness (Rz) and an average interval (Sm) of the concavo-convex pattern on the outer circumference face of the developer carrier satisfy conditions of 0.17≤Rz/r≤0.92 and 3.3≤Sm/r≤13.3.

Description

  The present invention relates to a developing device for developing an electrostatic latent image formed on an image carrier using a developer containing toner and a carrier in an image forming apparatus such as a copying machine and a printer, and a toner and a carrier in the developing device. The present invention relates to a developer carrying member that rotates while holding the developer on the outer peripheral surface thereof. Particularly characterized in that an appropriate amount of developer can be stably conveyed over a long period of time when the developer including toner and carrier is held and conveyed on the outer peripheral surface of the rotating developer carrier. It is.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, toner is supplied from a developing device to an electrostatic latent image formed on an image carrier such as a photoconductor, and the electrostatic latent image formed on the image carrier is The image is developed.

  As such a developing device, a two-component developing system using a developer containing toner and a carrier and a one-component developing system using only a toner without using a carrier are known. Yes.

  Here, in a developing device of a two-component development system using a developer containing toner and carrier, the developer containing toner and carrier is generally held on the outer peripheral surface of a rotating developer carrier, and this developer. The developer is conveyed toward the image carrier by the carrier, and the amount of the developer conveyed in this way is regulated by a regulating member, and a predetermined amount of developer is opposed to the image carrier by the developer carrier. The toner is introduced into the developing area, and the toner in the developer is supplied to the electrostatic latent image formed on the image carrier to perform development.

  Here, when the developer including the toner and the carrier is held on the outer peripheral surface of the rotating developer carrier and transported, a sufficient amount of developer is held on the outer peripheral surface of the developer carrier and transported. In order to achieve this, conventionally, it has been widely performed to form grooves and blasts on the outer peripheral surface of the developer carrying member to form irregularities on the outer peripheral surface of the developer carrying member.

  However, even when unevenness is formed on the outer peripheral surface of the developer carrying member as described above, if development is performed using such a developer carrying member for a long time, toner or toner may be deposited on the outer peripheral surface of the developer carrying member. The external additive adheres, and the convex portion on the outer peripheral surface of the developer carrier is worn by contact with the carrier. In particular, in a developer carrier made of a soft material such as aluminum, the developer There is a problem that the wear of the convex portion on the outer peripheral surface of the carrier increases, the amount of the developer conveyed by the developer carrier gradually decreases, and an image having a sufficient image density cannot be obtained.

  Conventionally, as disclosed in Patent Document 1, the toner particle size to be used and the ten-point average roughness Rz on the outer peripheral surface of the developer bearing member are defined, or as disclosed in Patent Document 2. In this way, the convex portion on the outer peripheral surface of the developer carrying member is a smooth surface, or as shown in Patent Document 3, the ten-point average roughness Rz and the average interval Sm of the unevenness on the outer peripheral surface of the developer carrying member. The thing which prescribed | regulated etc. is proposed.

  However, even in Patent Documents 1 and 3, when development is performed using a developer carrier for a long time, toner or an external additive of toner adheres to the outer peripheral surface of the developer carrier, or the developer The protrusions on the outer peripheral surface of the carrier cannot be sufficiently suppressed from being worn by contact with the carrier, and the amount of developer conveyed by the developer carrier is appropriately adjusted to It has been difficult to stably transport a large amount of developer over a long period of time.

  Moreover, in the thing of patent document 2, although the convex part in the outer peripheral surface of a developer carrier is a smooth surface, it is suppressed that it is abraded by contact with a carrier, but the outer peripheral surface of a developer carrier The toner and the external additive of the toner cannot be sufficiently suppressed, and the amount of the developer conveyed by the developer carrying member is appropriately adjusted to obtain an appropriate amount of the developer. It has been difficult to stably convey the material over a long period of time.

JP 2000-258992 A JP 2008-40400 A JP 2008-292971 A

  The present invention relates to a developing device for developing an electrostatic latent image formed on an image carrier using a developer containing toner and a carrier, and a developer containing toner and carrier on the outer peripheral surface of a rotating developer carrier. An object of the present invention is to enable an appropriate amount of developer to be stably conveyed over a long period of time when being held and conveyed.

  In the present invention, in order to solve the above-described problems, in the developer carrying member that rotates while holding the developer containing the toner and the carrier on the outer circumferential surface, irregularities are formed on the outer circumferential surface of the developer carrying member, The top of the convex portion is smoothed, and the inclination angle in the range of 50 to 80% from the lowest point of the concave portion on the outer peripheral surface of the developer carrier to the apex of the convex portion on the downstream side in the rotation direction of the developer carrier. The average value of θ is in the range of 5 ° to 24 °, and the reference length (l) in the roughness curve based on JIS B 0601 is 2.5 mm and the cutoff value (λc) is 2 on the outer peripheral surface of the developer carrier. The relationship between the ten-point average roughness (Rz) and the average spacing of the irregularities (Sm) determined at 0.5 mm and the average particle diameter (r) of the carrier is 0.17 ≦ Rz / r ≦ 0.92. The condition of 3.3 ≦ Sm / r ≦ 13.3 was satisfied.

  Further, in the developing device of the present invention, the developer carrying member as described above is used when the developer containing the toner and the carrier is held and conveyed on the outer peripheral surface of the rotating developer carrying member.

  Here, as in the developer carrier of the present invention, when the top of the convex portion on the outer peripheral surface on which the unevenness is formed is smoothed, the developer is held on the outer peripheral surface of the developer carrier and conveyed. In addition, the convex portion is suppressed from being worn by contact with the carrier, and the amount of the developer carried while being held on the outer peripheral surface of the developer carrier is suppressed.

  Further, as in the developer carrier of the present invention, in the range of 50 to 80% from the lowest point of the concave portion on the outer peripheral surface of the developer carrier to the apex of the convex portion on the downstream side in the rotation direction of the developer carrier. When the average value of the inclination angle θ is in the range of 5 ° to 24 °, the developer is appropriately held on the outer peripheral surface of the developer carrier when the developer carrier is rotated to transport the developer. A sufficient amount of developer is conveyed, and toner and toner external additives are prevented from adhering to the outer peripheral surface of the developer carrier. That is, when the average value of the inclination angle θ is less than 5 °, the carrier slips on the outer peripheral surface of the developer carrying member, and the developer is not properly held on the outer peripheral surface of the developer carrying member. It becomes impossible to transport a proper amount of developer. On the other hand, when the average value of the inclination angle θ exceeds 24 °, the force for pressing the carrier against the inclined surface becomes strong, and the toner or the external additive of the toner adheres to the outer peripheral surface of the developer carrier. When this developer carrier is used for a long time, the toner is not properly held on the outer peripheral surface of the developer carrier by the toner or the external additive of the toner adhering to the outer peripheral surface of the developer carrier, A sufficient amount of developer cannot be conveyed.

  Further, like the developer carrier of the present invention, the above ten-point average roughness (Rz) and the average interval (Sm) of the irregularities on the outer peripheral surface of the developer carrier, and the average particle diameter (r of the carrier) ) To satisfy the conditions of 0.17 ≦ Rz / r ≦ 0.92 and 3.3 ≦ Sm / r ≦ 13.3, an appropriate amount of developer is placed on the outer peripheral surface of the developer carrying member. It is held and transported. That is, when the value of Rz / r is less than 0.17 or the value of Sm / r is less than 3.3, the unevenness on the outer peripheral surface of the developer carrier becomes too small, and the developer carrier A sufficient amount of developer is not held on the outer peripheral surface of the sheet, and a sufficient amount of developer cannot be conveyed. On the other hand, if the value of Rz / r exceeds 0.92 or the value of Sm / r exceeds 13.3, the unevenness on the outer peripheral surface of the developer carrier becomes too large, and the outer periphery of the developer carrier is increased. The developer is excessively held on the surface and conveyed, and it becomes difficult to appropriately regulate the amount of the developer conveyed by the regulating member.

  As in the developer carrier in the present invention, the top of the convex portion of the unevenness formed on the outer peripheral surface is smoothed, and the rotation direction of the developer carrier from the lowest point of the concave portion on the outer peripheral surface of the developer carrier The average value of the inclination angle θ in the range of 50 to 80% to the apex of the convex portion on the downstream side is set in the range of 5 ° to 24 °, and the roughness curve based on JIS B 0601 on the outer peripheral surface of the developer carrier. 10-point average roughness (Rz) and average interval of irregularities (Sm) determined with a reference length (l) of 2.5 mm and a cutoff value (λc) of 2.5 mm, and the average particle size of the carrier When the relationship with the diameter (r) satisfies the conditions of 0.17 ≦ Rz / r ≦ 0.92, 3.3 ≦ Sm / r ≦ 13.3, development is performed on the outer peripheral surface of the developer carrier. When the developer is held and transported, an appropriate amount of developer is added to the developer carrier. While being held on the peripheral surface and being transported, the convex portion on the outer peripheral surface of the developer carrying member is worn out, or toner or an external additive of the toner adheres to the outer peripheral surface of the developer carrying member. Is suppressed.

  As a result, in the developing device using the developer carrier as described above, even if the developer carrier is used for a long time, an appropriate amount of developer is stably conveyed over a long period of time by the developer carrier. As a result, good development can be performed over a long period of time.

1 is a schematic explanatory diagram of a developing device according to an embodiment of the present invention. FIG. 5 is a partial schematic diagram illustrating a state of an outer peripheral surface of a developer carrier used in the developing device according to the embodiment. In the developer carrier used in the developing device according to the above-described embodiment, in the range of 50 to 80% from the lowest point of the concave portion on the outer peripheral surface to the apex of the convex portion on the downstream side in the rotation direction of the developer carrier. It is the partial schematic diagram which showed inclination-angle (theta). In the developer carrier used in the developing device according to the above-described embodiment, it is a schematic diagram showing a state in which the force acting on the carrier changes depending on whether the inclination angle θ is large or small. Using the developer carriers A2, A10, A26, A34, and A41 prepared in the experimental examples, the results of determining the relationship between the inclination angle θ and the remaining developer conveyance rate (%) at each durability point are shown. FIG.

  Next, a developing device according to an embodiment of the present invention and a developer carrier used in the developing device will be specifically described with reference to the accompanying drawings. The developing device and developer carrier according to the present invention are not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In the developing device in this embodiment, as shown in FIG. 1, the development is such that the magnet member 11 is fixedly provided on the inner peripheral side in the opening portion of the housing 10 in which the developer D containing toner and carrier is accommodated. An agent carrier 12 is provided. Further, a partition wall 13 is provided in the housing 10 along the axial direction of the developer carrier 12, and the partition portion 13 allows the first transport member 14 a to be provided in the housing 10. 14 and the second transport unit 15 provided with the second transport member 15a.

  Here, when developing the electrostatic latent image formed on the image carrier 1 using the developing device, as shown in FIG. 1, the developer carrier 12 is spaced from the image carrier 1 by a required distance. The developer D accommodated in the housing 10 is mixed and stirred by the first and second conveying members 14a and 15a, and the first conveying unit 14 and the second conveying unit 14a are mixed. The developer D is transported in the opposite direction by the transport unit 15, and the developer D is passed between the first transport unit 14 and the second transport unit 15 through circulation ports (not shown) provided at both ends of the partition wall 13. Make it circulate with.

  Then, a part of the developer D transported in the first transport unit 14 is supplied to the outer peripheral surface of the developer carrier 12 by the first transport member 14a, and the developer thus supplied is supplied D is held on the outer peripheral surface of the developer carrier 12 by the magnet member 11 provided on the inner peripheral side of the developer carrier 12.

  Then, the developer carrying member 12 is rotated, and the developer D held on the outer peripheral surface thereof is conveyed toward the developing region facing the image carrier 1 by the developer carrying member 12, and to the developing region. In the course of transport, the amount of developer D transported to the development area is regulated by a regulating member 16 provided so as to face the developer carrying member 12 with a required interval therebetween, and the development regulated in this way. The developer D is guided to the development area facing the image carrier 1 by the developer carrier 12 for development.

  Here, in this embodiment, as the developer carrier 12, the outer peripheral surface of the developer carrier 12 made of aluminum or the like is blasted using abrasive grains such as silicon beads having a small particle size. Then, after forming fine irregularities on the outer circumferential surface of the developer carrier 12, the outer circumferential surface of the developer carrier 12 on which fine irregularities are formed using an elastic medium in which abrasive grains are kneaded into the elastic body is secondary. As shown in FIG. 2, a blast treatment is used to smooth the convex portions 12 a in the fine irregularities formed on the outer peripheral surface of the developer carrier 12.

  In the developer carrier 12 in this embodiment, as shown in FIG. 3, when the concave portions 12b and the convex portions 12a with the convex portions 12a smoothed are provided on the outer peripheral surface as described above, the developer carrier is provided. The average value of the inclination angle θ in the range of 50 to 80% from the lowest point of the concave portion 12b on the outer peripheral surface of the body 12 to the apex of the convex portion 12a on the downstream side in the rotation direction x of the developer carrier 12 is 5 ° to The range was set to 24 °.

  Here, as shown in FIG. 4A, when the inclination angle θ in the developer carrier 12 increases, the carrier C is transferred to the developer carrier 12 by the force F acting on the carrier C in the developer D. The force Fb pressing in the vertical direction with respect to the outer peripheral surface of the toner becomes stronger, the toner in the developer D and the external additive of the toner gradually adhere to the outer peripheral surface of the developer carrier 12, and the developer D becomes the developer carrier. Accordingly, the developer D is not properly held on the outer peripheral surface 12 and a sufficient amount of the developer D cannot be conveyed.

  On the other hand, as shown in FIG. 4B, when the inclination angle θ in the developer carrier 12 is reduced, the carrier C is removed from the developer carrier 12 by the force F acting on the carrier C in the developer D. The force Fb pressing in the direction perpendicular to the outer peripheral surface is weakened, and the toner and the external additive of the toner in the developer D are suppressed from adhering to the outer peripheral surface of the developer carrier 12, while the carrier C is The force Fa in the direction of movement along the outer peripheral surface of the developer carrier 12 is increased. If the inclination angle θ is too small, the carrier C slips on the outer peripheral surface of the developer carrier 12, and the developer D is not properly held on the outer peripheral surface of the developer carrier 12, and a sufficient amount is obtained. The developer D cannot be transported.

  Then, as in the developer carrier 12 in this embodiment, when the inclination angle θ is in the range of 5 ° to 24 °, toner and toner external additives adhere to the outer peripheral surface of the developer carrier 12. In addition, the developer D is appropriately held on the outer peripheral surface of the developer carrier 12, and a sufficient amount of the developer D is conveyed.

  The ten-point average obtained by setting the reference length (l) in the roughness curve based on JIS B 0601 to 2.5 mm and the cut-off value (λc) to 2.5 mm on the outer peripheral surface of the developer carrier 12. 2. The relationship between the roughness (Rz) and the average spacing (Sm) of the irregularities and the average particle diameter (r) of the carrier C in the developer D is 0.17 ≦ Rz / r ≦ 0.92. The condition of 3 ≦ Sm / r ≦ 13.3 was satisfied.

  In this case, as described above, a sufficient amount of the developer D is not held on the outer peripheral surface of the developer carrier 12, and a sufficient amount of the developer D cannot be conveyed, or the developer carrying is not possible. The developer D is excessively held and conveyed on the outer peripheral surface of the body 12, and it is difficult to properly regulate the amount of the developer D conveyed to the image carrier 1 by the regulating member 16. An appropriate amount of developer D is stably conveyed to the image carrier 1 by the developer carrier 12.

  As a result, when development is performed using the developer carrier 12 as described above, a constant amount of developer D is stably conveyed to the image carrier 1 over a long period of time by the developer carrier 12. As a result, good development can be stably performed over a long period of time.

Next, in a developing device used in a commercially available image forming apparatus (manufactured by Konica Minolta: bizhub C360), a carrier having a particle diameter r of 30 μm and a magnetization of 43 Am ² / kg is used as a carrier in the developer. In addition, the developer carrier having the above-described inclination angle θ, ten-point average roughness (Rz), and average interval of irregularities (Sm) changed by changing the conditions for forming irregularities on the outer peripheral surface of the developer carrier. A1 to A42 were used.

  Here, in obtaining the developer carriers A1 to A42, as shown in Table 1 below, silicon beads having different particle diameters are used and processed on the outer peripheral surface of the developer carrier made of aluminum. After changing the pressure and blasting each for 60 seconds to form irregularities on the outer peripheral surface of each developer carrier, a commercially available elastic medium having a particle size of 300 to 400 μm (Sirius # 3000 manufactured by Fuji Seisakusho) , And a secondary blasting process at a processing pressure of 0.4 MPa for 80 seconds each to smooth the top of the protrusions in the irregularities formed on the outer peripheral surface of each developer carrier, A42 was produced.

  For the developer carriers A1 to A42 produced as described above, the inclination angle θ is obtained, and the ten-point average roughness (Rz), the average interval of unevenness (Sm), and the average particle diameter of the carrier ( r) and the values of Rz / r and Sm / r were determined, and the results are shown in Table 2 below.

The developer carrying bodies A1 to A42 described above were used in the developing device, respectively, and the developer transport characteristics (initial transport characteristics) at the initial stage were examined. The results are shown in Table 2. Here, with respect to the initial conveyance characteristics, when the distance between each developer carrier A1 to A42 and the regulating member is set in the range of 0.3. are 150 to 250 g / a when the conveyance amount of ^{m 2} was obtained while displaying a "relevant", the case where the amount of the developer conveyed is less than 150 g / ^{m 2} "Out", the amount of developer conveyed 250 g / m ^The case of exceeding ² was indicated as “excess”.

  As a result, developer carriers A5 to A7, A12 to A14, A20, A21, A27, and A28 having Rz / r values of less than 0.17 and Sm / r values of less than 3.3. , A35, and A42, the initial transport characteristics are “insufficient”, and an appropriate amount of developer cannot be transported from the beginning.

  Further, in the developer carriers A22, A29, A30, A36 to A38 in which the value of Rz / r exceeds 0.92 or the value of Sm / r exceeds 13.3, the above initial transport characteristics are Development that is “excess” and the amount of the developer conveyed by the developer carrier greatly fluctuates only by a slight change in the distance between the developer carrier and the regulating member. It becomes difficult to properly regulate the amount of the agent by the regulating member.

  On the other hand, developer carriers A1 to A4 whose values of Rz / r and Sm / r satisfy the conditions of 0.17 ≦ Rz / r ≦ 0.92 and 3.3 ≦ Sm / r ≦ 13.3. , A8 to A11, A15 to A19, A23 to A26, A31 to A34, and A39 to A41, the above-mentioned initial transport characteristics are “suitable”, and an appropriate amount of developer is transported by the developer carrier from the beginning. I was able to.

  Next, a developer carrier A2 having an inclination angle θ of 6 °, a developer carrier A10 having an inclination angle θ of 8 °, a developer carrier A26 having an inclination angle θ of 16 °, and an inclination angle θ of 24. Using a developer carrier A34 with a tilt angle of 30 ° and a developer carrier A41 with a tilt angle θ of 28 °, a durability test of 300,000 sheets is performed, and the developer at each durability point relative to the developer transport amount in the initial stage. The remaining amount (%) of the transport amount was determined, and the results are shown in FIG.

  As a result, the smaller the inclination angle θ, the lower the decrease in the remaining amount of developer transport after the endurance, and the developer carrying bodies A2, A10, and the like in which the inclination angle θ is in the range of 5 ° to 24 °. In A26 and A34, even after the endurance test of 300,000 sheets was performed, the remaining conveyance rate did not fall below 75%, and image quality did not deteriorate. On the other hand, in the developer carrying member A41 having the inclination angle θ of 28 °, the remaining amount of conveyance was 75% or less at the time of the endurance test of 100,000 sheets, and the image quality was deteriorated.

DESCRIPTION OF SYMBOLS 1 Image carrier 10 Housing 11 Magnet member 12 Developer carrier 12a Convex part 12b Concave part 13 Bulkhead 14 1st conveyance part 14a 1st conveyance member 15 2nd conveyance part 15a 2nd conveyance member 16 Restriction member C Carrier D Developer θ Inclination angle

Claims (2)

  In a developer carrying member that rotates while holding a developer containing toner and a carrier on the outer peripheral surface, unevenness is formed on the outer peripheral surface of the developer carrying member, and the top of the convex portion is smoothed, and the developer The average value of the inclination angle θ in the range of 50 to 80% from the lowest point of the concave portion on the outer peripheral surface of the carrier to the apex of the convex portion on the downstream side in the rotation direction of the developer carrier is in the range of 5 ° to 24 °. There is a ten-point average roughness obtained by setting the reference length (l) in the roughness curve based on JIS B 0601 to 2.5 mm and the cut-off value (λc) to 2.5 mm on the outer peripheral surface of the developer carrier. Rz) and the average spacing of the irregularities (Sm) and the average particle diameter (r) of the carrier are 0.17 ≦ Rz / r ≦ 0.92, 3.3 ≦ Sm / r ≦ 13.3. A developer carrier characterized by satisfying the following conditions.   2. A developing device using the developer carrying member according to claim 1, wherein a developer containing toner and a carrier is held and conveyed on an outer peripheral surface of a rotating developer carrying member. .

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