JP2009145474A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a toner from being deteriorated on an outer circumferential face of a toner carrier with regulation by a regulation member, or the toner from being film-formed on the outer circumferential face of the toner carrier, in a developing device of making the regulation member pressure-contact with the outer circumferential face of the toner carrier, to be held onto the outer circumferential face of the toner carrier, and of regulating the toner conveyed to a developing area opposed to the toner carrier, and to carry out proper development. <P>SOLUTION: A metal roller with a roughened outer circumferential face is used as the toner carrier, an elastic plate having JIS A hardness within a range of 65-75 is used as the regulation member, a Vickers hardness Hv of the outer circumferential face of the toner carrier is brought within a range of 40-70, and regulation pressure of the regulation member pressure-contacting with the toner carrier is brought within a range of 10-30 N/m, in the developing device of making the regulation member 5 pressure-contact with the outer circumferential face of the toner carrier 4, to be held onto the outer circumferential face of the toner carrier, and of regulating the toner conveyed to the developing area opposed to the toner carrier. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device used to develop an electrostatic latent image formed on an image carrier in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a combination of these machines. While being held on the outer peripheral surface of the carrier and being transported to the developing region facing the image carrier, a regulating member is pressed against the outer peripheral surface of the toner carrier to regulate the amount of toner conveyed to the developing region. The present invention relates to a developing device.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a combination of these, various developing devices are used to develop an electrostatic latent image formed on an image carrier.

  As such a developing device, in addition to a two-component developing type developing device including a carrier and toner in a developer, a one-component developing type developing device that does not use a carrier is known.

  Here, in the developing device of the above one-component development system, in order to stably convey an appropriate amount of toner to the developing area facing the image carrier by the toner carrier, the toner is generally carried by the toner. While being held on the outer peripheral surface of the body and being conveyed to the developing region facing the image carrier, a regulating member is pressed against the outer circumferential surface of the toner carrier, and is held by the regulating member on the outer circumferential surface of the toner carrier. The amount of toner conveyed to the development area is regulated and the toner is frictionally charged.

  As the toner carrier, conventionally, a metal roller or a metal roller provided with an elastic layer on the outer peripheral surface is used.

  However, when a toner carrier made of a metal roller is used, it becomes difficult to transport a sufficient amount of toner by this toner carrier, and a regulating member is pressed against the outer peripheral surface of the toner carrier to develop it. When the toner conveyed to the region is regulated, a large load is applied to the toner by the pressure contact force by the regulating member, and the toner on the outer peripheral surface of the toner carrier is broken and fine powder is generated. In particular, when the development speed is increased in order to form an image at high speed, the toner cracks severely and a lot of fine powder is generated. The fine powder gradually increases and is fused to the outer peripheral surface of the toner carrier. There is a problem that unevenness of density occurs in the formed image.

  Further, in the case of the toner carrier having the elastic layer provided on the outer peripheral surface of the metal roller as described above, the manufacturing cost is high, and the elastic layer provided on the outer peripheral surface of the metal roller is deteriorated and used for a long time. However, when the elastic layer provided on the outer peripheral surface of the metal roller is made thick, there is a problem that the molding accuracy of the toner carrier is deteriorated and stable development cannot be performed.

  In addition, conventionally, as disclosed in Patent Document 1, a toner bearing member is formed by sandblasting the surface of a metal roller to form irregularities and alumite-treating the irregularity forming portion. There has been proposed an improved toner carrying performance and wear resistance in a toner carrier.

  However, when the regulating member is pressed against the outer peripheral surface of the toner carrier as described above to restrict the toner held on the outer peripheral surface of the toner carrier and transported to the development region, the toner carrier Since the surface hardness is high, the toner held on the outer peripheral surface of the toner carrier is cracked by the pressure contact of the regulating member to generate fine powder, or the toner deteriorates. As a result, there is a problem that toner is poorly charged and proper development cannot be performed.

In addition, when the surface of the toner carrier is anodized as described above, there is a problem that the manufacturing cost is high.
JP 2001-318526 A

  In the present invention, while the toner is held on the outer peripheral surface of the toner carrier and is transported to the development region facing the image carrier, the regulating member is brought into pressure contact with the outer peripheral surface of the toner carrier and is transported to the development region. An object of the present invention is to solve the above-described various problems in a developing device that regulates toner.

  In the developing device according to the present invention, particularly when a metal roller having a rough outer peripheral surface is used for the toner carrier, the toner held on the outer peripheral surface of the toner carrier by the pressure contact of the regulating member is reduced. Properly prevents cracking and generation of fine powder, deterioration of toner, and filming of toner on the outer peripheral surface of the toner carrier, and controls the toner held on the outer peripheral surface of the toner carrier. It is an object to be appropriately regulated by a member over a long period of time so that proper development can be performed over a long period of time, and the manufacturing cost of the toner carrier can be reduced.

  In the present invention, in order to solve the above-described problems, a toner carrier that holds the toner on the outer peripheral surface and conveys the toner to a developing region facing the image carrier, and is brought into pressure contact with the outer peripheral surface of the toner carrier. In a developing device having a regulating member that regulates toner conveyed to the developing region, a metal roller having a rough outer peripheral surface is used for the toner carrier, and a JIS A hardness of 65 is used for the regulating member. An elastic plate in the range of ˜75 is used, the Vickers hardness Hv of the outer peripheral surface of the toner carrier is in the range of 40 to 70, and the regulation pressure of the regulation member to be in pressure contact with the toner carrier is 10 to 10. The range was 30 N / m.

  Here, an elastic plate having a JIS A hardness in the range of 65 to 75 is used as the restricting member. If the restricting member has a JIS A hardness of less than 65, the outer peripheral surface of the toner carrier is used. Due to the pressure contact, the pressure contact surface of the restriction member is gradually scraped and damaged, and streak noise is generated in the formed image. On the other hand, when the JIS A hardness of the restriction member exceeds 75, the restriction member is restricted. This is because the deterioration of the toner is increased, and the outer peripheral surface of the roughened toner carrier is gradually scraped, so that the toner conveyance performance is lowered.

  In addition, the restriction pressure of the restriction member that is brought into pressure contact with the toner carrier is set in the range of 10 to 30 N / m because the toner held on the outer peripheral surface of the toner carrier when the restriction pressure of the restriction member is less than 10 N / m. However, if the regulating pressure of the regulating member exceeds 30 N / m, the toner held on the outer peripheral surface of the toner carrier may be cracked when the toner is regulated. This is because the toner easily deteriorates.

  Also, the reason why the Vickers hardness Hv of the outer peripheral surface of the toner carrier is set in the range of 40 to 70 is that when the Vickers hardness Hv of the outer peripheral surface of the toner carrier is less than 40, it is regulated by the regulating member as described above. When the convex portion on the outer peripheral surface of the toner carrier is gradually scraped, the toner carrying ability of the toner carrier gradually decreases, and the image density of the formed image is lowered. On the other hand, when the Vickers hardness Hv exceeds 70, This is because the toner is gradually filmed on the outer peripheral surface of the toner carrier, and the toner is not appropriately charged.

  Here, as a material constituting the metal roller used for the toner carrier, various metals can be used, but it is preferable to use a lightweight and low-cost aluminum-based metal. In order to make the Vickers hardness Hv in the range of 40 to 70 above, for example, an Al—Mg alloy or an Al—Mg—Si alloy is used, and the composition ratio of these alloys and the heat treatment conditions are changed. Can be adjusted.

  In addition, if the surface roughness on the outer peripheral surface of the toner carrier is small, the toner carrying ability of the toner carrier is reduced, and it becomes difficult to carry sufficient toner, while the surface roughness is large. If it becomes too large, the toner is not properly regulated by the regulating member, and the toner is not properly charged. Therefore, the arithmetic average roughness Ra on the outer peripheral surface of the toner carrier is in the range of 1.0 to 1.4 μm. It is preferable to make it.

  In the developing device of the present invention, as described above, a metal roller having a roughened outer peripheral surface is used for the toner carrier that holds the toner on the outer peripheral surface and conveys the toner to the developing region facing the image carrier. An elastic plate having a JIS A hardness in the range of 65 to 75 is used as a regulating member that regulates the toner conveyed to the development area by being pressed against the outer circumferential surface of the toner carrier, Since the Vickers hardness Hv is in the range of 40 to 70 and the regulation pressure of the regulation member that is in pressure contact with the toner carrier is in the range of 10 to 30 N / m, the pressure contact surface of the regulation member is damaged or roughened toner The outer peripheral surface of the carrier is not gradually scraped and the toner conveyance performance is not lowered, and the toner on the outer peripheral surface of the toner carrier is deteriorated due to the restriction by the restriction member. Also to be properly prevented from or is filming on the peripheral surface of toner support of.

  As a result, in the developing device of the present invention, even when a metal roller having a rough outer peripheral surface is used for the toner carrier, the toner held on the outer peripheral surface of the toner carrier is transferred by the restriction member. Appropriate development is achieved over a long period of time, appropriate development can be performed stably over a long period of time, and good images can be stably obtained over a long period of time.

  Further, in the developing device of the present invention, since it is not necessary to anodize the outer peripheral surface of the roughened metal roller, the manufacturing cost of the toner carrier is also reduced.

  Next, a developing device according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the developing device according to the present invention is not limited to the one shown in the following embodiment, and can be appropriately changed and implemented without changing the gist thereof.

  In the developing device of this embodiment, as shown in FIG. 1, the toner t accommodated in the apparatus main body 1 is sent to the toner supply member 3 formed into a roller shape by the toner feeding member 2, and the toner supply member 3 is The toner t is rotated so that the toner t is supplied from the toner supply member 3 to the toner carrier 4 made of a metal roller.

  The toner t thus supplied is held on the outer peripheral surface of the toner carrier 4, and the toner t is conveyed toward the image carrier P by the rotation of the toner carrier 4 and the apparatus main body. 1, the end of the restricting member 5 made of an elastic plate having a JIS A hardness in the range of 65 to 75 is brought into pressure contact with the outer peripheral surface of the toner carrier 4 so that the outer periphery of the toner carrier 4 is The amount of toner t held on the surface and conveyed is regulated and the toner t is charged.

  Then, the toner t regulated and charged by the regulating member 5 is guided to the developing region facing the image carrier P by the toner carrier 4, and the electrostatic latent image formed on the image carrier P is guided. To develop.

  Here, in the developing device of this embodiment, the outer peripheral surface of the toner carrier 4 made of the metal roller is roughened by blasting or the like, and the arithmetic average roughness Ra of the outer peripheral surface is 1.0. The Vickers hardness Hv on the outer peripheral surface is adjusted to 40 μm by adjusting the composition ratio of the alloy in the Al—Mg alloy or Al—Mg—Si alloy and the heat treatment conditions as described above. A metal roller having a range of ˜70 is used.

  On the other hand, as the restricting member 5 made of an elastic plate having a JIS A hardness in the range of 65 to 75, a member made of urethane rubber is generally used, and the hardness, durability, charging performance, etc. are appropriately set. In order to adjust, silicone rubber or fluorine rubber is added as necessary.

  When the regulating member 5 made of the elastic plate is brought into pressure contact with the outer peripheral surface of the toner carrier 4, the toner carrier is made according to the hardness, elastic coefficient, thickness, etc. of the regulating member 5. 4 is adjusted so that the regulating pressure by the regulating member 5 is in the range of 10 to 30 N / m.

  In this case, the pressure contact surface of the regulating member 5 is not damaged as described above, or the roughened outer peripheral surface of the toner carrier 4 is not scraped, and the toner conveyance performance is not deteriorated. Further, the toner t on the outer peripheral surface of the toner carrier 4 is prevented from being deteriorated due to the restriction by the restriction member 5, and the toner t is prevented from being filmed on the outer peripheral surface of the toner carrier 4. The toner t held on the surface is appropriately regulated by the regulating member 4 over a long period of time, and the electrostatic latent image formed on the image carrier P is appropriately developed so that a good image can be stably obtained over a long period of time. become.

  Next, a commercially available printer (manufactured by Konica Minolta: Magiccolor 2430) was modified to change the type of toner carrier and regulating member used.

  Here, as the toner carrier, an Al—Mg—Si based alloy is used, and the five kinds of Vickers hardness Hv on the outer peripheral surface are changed to 34, 43, 45, 53, 55, 56 by changing the heat treatment conditions. Three types of toner carriers A1 to A6 made of Al-Mg-Si alloy and Al-Mg alloy were used, and Vickers hardness Hv on the outer peripheral surface was changed to 65, 67, 85 by changing the heat treatment conditions. Toner carriers B1 to B3 made of an Al—Mg alloy are used. Note that the surface roughness of the outer peripheral surface of each toner carrier described above was such that the arithmetic average roughness Ra of the outer peripheral surface was about 1.2 μm by blasting.

  Further, as the restricting members, three kinds of restricting members C1 to C3 made of urethane rubber and having a thickness of 2 mm and having the JIS A hardness of 63, 70 and 77 are used.

  In Examples 1 to 5 and Comparative Examples 1 to 6, the toner carriers A1 to A6, B1 to B3 and the regulating members C1 to C3 are used in combination as shown in Table 1 below. At the same time, the amount of regulation member biting into the toner carrier is adjusted, and the regulation pressure of the regulation member against the toner carrier is set to 23 N / m in Example 1 and Comparative Examples 2 and 6, as shown in the table. Example 2 and 3 were 17 N / m, Examples 4 and 5 were 28 N / m, Comparative Examples 1 and 4 were 22 N / m, Comparative Example 3 was 12 N / m, and Comparative Example 5 was 33 N / m. .

  Then, using the printers using the developing devices of Examples 1 to 5 and Comparative Examples 1 to 5, image density and fog were evaluated, and the results are shown in Table 2 below.

  Here, for the image density, 4500 black solid images were printed, and the initial image density was measured with a reflection densitometer (Macbeth: TD904) at 1000 sheets, 2500 sheets, and 4500 sheets. Image density was evaluated.

  Regarding the evaluation of the image density, (5) when the reflection density is 1.0 or more and less than 1.2, (4) when the reflection density is 1.2 or more and less than 1.4, and 0.8 or more and less than 1.0. The case of (3), the case of 1.4 or more is (2), and the case of less than 0.8 is (1). The preferable range of the reflection density is 1.0 or more and less than 1.4. If the reflection density is less than 1.0, a sufficient image density cannot be obtained. And the reproducibility of fine lines is poor.

  As for the fog, 4500 white solid images were printed, and the fog was evaluated on the initial 1000 sheets, 2500 sheets, and 4500 sheets.

  As for the evaluation of the fog (5), when there is no fog on the image, the fog can be slightly confirmed by microscopic observation, but when it cannot be visually confirmed (4), the fog can be confirmed by visual observation. The case where there is no problem (3), the fog can be visually confirmed, and the case where the problem occurs in practice (2), and the case where a lot of fog occurs in the entire image is (1).

  As is apparent from this result, when a toner carrier made of a metal roller having a rough outer peripheral surface and a regulating member made of an elastic plate are used, the condition that the JIS A hardness of the regulating member is 65 to 75 is satisfied. When using the developing device of Comparative Examples 1 and 2 that do not satisfy, or when using the developing device of Comparative Examples 3 and 5 that does not satisfy the condition that the regulation pressure of the regulating member is 10 to 30 N / m, When the developing devices of Comparative Examples 4 and 6 that did not satisfy the condition that the Vickers hardness Hv of the outer peripheral surface was 40 to 70, an appropriate image density could not be obtained, or the image was fogged.

  On the other hand, the Vickers hardness Hv of the outer peripheral surface of the toner carrier is in the range of 40 to 70, the JIS A hardness in the regulation member is in the range of 65 to 75, and the regulation of the regulation member to be brought into pressure contact with the toner carrier. When the developing devices of Examples 1 to 5 having a pressure in the range of 10 to 30 N / m were used, a good image having an appropriate image density and free from fogging was obtained.

FIG. 3 is a schematic explanatory view showing a state in which an electrostatic latent image formed on an image carrier is developed using a developing device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Toner feeding member 3 Toner supply member 4 Toner carrier 5 Regulating member P Image carrier t Toner

Claims (3)

  A toner carrier that holds the toner on the outer peripheral surface and conveys the toner to the developing region facing the image carrier; and a regulating member that presses the outer peripheral surface of the toner carrier and regulates the toner conveyed to the developing region. In the developing device, a metal roller having a rough outer peripheral surface is used for the toner carrier, and an elastic plate having a JIS A hardness in the range of 65 to 75 is used for the regulating member. A developing device characterized in that the Vickers hardness Hv of the outer peripheral surface of the toner carrying member is in the range of 40 to 70, and the regulating pressure of the regulating member brought into pressure contact with the toner carrying member is in the range of 15 to 30 N / m. .   2. The developing device according to claim 1, wherein the metal roller in the toner carrier is made of an aluminum-based metal.   3. The developing device according to claim 1, wherein the arithmetic average roughness Ra of the outer peripheral surface of the toner carrier is in the range of 1.0 to 1.4 [mu] m.

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