JP2005195881A - Toner supply roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner supply roller which enables obtaining of superior images. <P>SOLUTION: The toner supply roller is used in a development apparatus comprising a toner carrier, disposed opposite to a latent image carrier to elicit a latent image formed on the latent image carrier; a toner supply roller which supplies toner to the toner carrier and is brought into contact with the toner carrier under relative movement to scrape away the excess toner; a regulating member disposed in contact with the toner carrier to regulate the amount of the toner supplied onto the toner carrier, wherein the toner supply roller has a sponge layer, whose tanδ measured at 10 Hz satisfies the relations (1): tanδ<0.5-t/200, and (2): tanδ>0.05-t/1,600 at a temperature (t°C) within the range of 0-40°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner supply roller used in a developing device mounted on a recording apparatus or the like by electrophotography.

  As a conventional toner supply roller, a toner conveyance roller having a surface layer formed of polyurethane foam and a urethane foam cell diameter of 30 to 200 μm is proposed (for example, Patent Document 1). reference.).

Further, by foam molding of the polyurethane raw material, a continuous cell foam structure is formed around the core metal, the elongation at break is 100% or more, the tear strength is 0.4 kgf / cm or more, and the hardness is 350 g or less. A soft polyurethane sponge layer having a skin layer that forms a smooth surface is formed, and each cell located immediately below the skin layer is formed at a portion corresponding to the center of the cell where the thickness of the skin layer is reduced. There has been proposed a toner supply roller that opens to the outside independently through openings having a diameter of 100 to 800 μm, and that the total opening area of the cells occupies 20% or more of the surface of the skin layer (for example, , See Patent Document 2). Further, Patent Document 2 proposes a toner supply roller having a ventilation characteristic in which a ventilation amount is 30 cc / cm ² · sec or less.

  In addition, in an electrophotographic rubber member used in an image forming apparatus for removing or regulating toner, or used for charging or development, the peak temperature of tan δ (1 Hz) is lower than −10 ° C. and extrapolation of complex elastic modulus. A rubber member for electrophotography made of a rubber elastic body whose end point on the low temperature side of the rubber region obtained from the above is lower than 0 ° C. is proposed (for example, Patent Document 3).

However, in the above-mentioned patent document, by setting the value of tan δ at the actual use temperature of the sponge layer of the toner supply roller to be in a specific range, the toner accumulated in the sponge layer of the toner supply roller can be compared with the fresh toner. This facilitates the replacement and prevents the occurrence of a phenomenon that the toner is charged to the opposite polarity of the toner due to the frictional charging of the toner due to the toner entering and staying in the sponge layer of the toner supply roller. There is no disclosure of providing a toner supply roller that improves the fogging phenomenon, reduces toner consumption, prevents smearing of the recording material, and provides an excellent image.
Japanese Patent Laid-Open No. 3-155575 JP-A-10-221945 JP 2000-172141 A

  The present invention has been made in view of such a state of the art, and an object of the present invention is to facilitate replacement of toner that has entered and stayed in the toner supply roller with toner in the developing chamber. Another object of the present invention is to provide a toner supply roller that can maintain the chargeability of toner normally and obtain an excellent image.

  The above object is achieved by the toner supply roller according to the present invention. That is, the present invention provides a toner carrier disposed opposite to the latent image carrier to visualize the latent image formed on the latent image carrier, and supplies toner to the toner carrier. And a toner supply roller that contacts the toner carrier while moving relative to the toner carrier to scrape off excess toner, and a toner carrier that regulates the amount of toner supplied onto the toner carrier. A toner supply roller used in a developing device having a regulating member disposed in contact with the toner supply roller, wherein the toner supply roller has a tan δ measured at 10 Hz in a temperature (t ° C.) range of 0 to 40 ° C. A toner supply roller having a sponge layer satisfying the relationship of the formulas (1) and (2).

tan δ <0.5-t / 200 (1)
tan δ> 0.05−t / 1600 (2)
Further, in the toner supply roller of the present invention, it is preferable that the sponge layer is made of polyurethane.

  In the toner supply roller of the present invention, the toner that has entered and stayed in the sponge layer and the toner in the developing chamber are smoothly exchanged, whereby the chargeability of the toner is kept normal and an excellent image is obtained. Makes it possible to obtain

  The toner supply roller of the present invention includes a toner carrier disposed opposite to the latent image carrier to visualize a latent image formed on the latent image carrier, and a toner with respect to the toner carrier. A toner supply roller that contacts the toner carrier while moving relative to the toner carrier to scrape off excess toner, and the toner carrier to regulate the amount of toner supplied on the toner carrier. The toner supply roller is mounted on and used in a developing device having a regulating member disposed in contact with the body.

  An example of such a developing device is shown in FIG. This developing device is provided with an opening (not shown) facing the latent image carrier 1 and includes a developing chamber (not shown) for containing toner. In this developing chamber, a toner carrier 2 that conveys the toner toward the latent image carrier 1 while carrying toner is disposed opposite the latent image carrier 1.

  The toner carrier 2 is disposed in the developing chamber (not shown) so that a part of the outer peripheral surface of the toner carrier 2 protrudes to the outside from the opening of the developing chamber (not shown). The toner carrier 2 is held with a gap of 50 to 500 μm from the latent image carrier 1, and a development area for supplying the toner carried on the toner carrier 2 toward the latent image carrier 1 is provided. Is formed. In the developing chamber (not shown), the toner supply roller 4 of the present invention for supplying toner to the toner carrier 2 is mounted.

  A developing bias is normally applied to the toner carrier 2.

  Above the toner carrier 2, a regulating member 3 that regulates the amount (layer thickness) of toner carried on the toner carrier 2 is disposed. The regulating member 3 is usually attached to a developing chamber (not shown). A blowout prevention sheet (not shown) is usually provided below the toner carrier 2 in order to prevent the toner from blowing out from the lower part of the developing chamber (not shown).

  During development, toner is applied to the toner carrier 2 by the toner supply roller 4. The toner carrier 2 is rotated in the direction of the arrow in the figure, and the toner carried on the toner carrier 2 is regulated to a predetermined amount (layer thickness) by the regulating member 3 and then sent to the current area. In the developing region, an electric field is formed by the developing bias, and the toner on the toner carrier 2 flies toward the portion where the latent image on the latent image carrier 1 is formed by the force of the electric field, and the latent image is developed. Then, an unfixed toner image is formed on the latent image carrier 1.

  The toner supply roller 4 and the toner carrier 2 normally rotate in the same direction, and the toner supply roller 4 strips off the remaining toner on the toner carrier 2.

  An example of the configuration of the toner supply roller of the present invention is schematically shown in FIG. As shown in FIG. 2, the toner supply roller has a configuration including a cylindrical cored bar 21 and a cylindrical sponge layer 22 formed concentrically with the cored bar 21 on the outer periphery thereof.

  The toner supply roller rotates while applying toner in the developing chamber (not shown) around the toner supply roller 4, and the sponge layer 22 of the toner supply roller 4 is dented in the first half of the nip with the toner carrier 2. The toner present in the toner supply roller 4 is discharged together with air. In the latter half of the nip, the dent is recovered, and when the dent is recovered, excess toner on the toner carrier 2 and the toner supply roller 4 is sucked together with air and accumulated in the toner supply roller 4. The toner in the nip portion is frictionally charged due to the relative movement between the toner supply roller 4 and the toner carrier 2. The excess toner is mechanically pushed into the cells of the sponge layer 22. Accordingly, it is required that the amount of toner discharged from the sponge layer 22 and the amount of suction be in an appropriate range.

  In the toner supply roller of the present invention, the sponge layer 22 has a tan δ measured at 10 Hz satisfying the relationship of the following formulas (1) and (2) at a temperature (t ° C.) in the range of 0 to 40 ° C. It is characterized by having.

tan δ <0.5-t / 200 (1)
tan δ> 0.05−t / 1600 (2)
If the sponge layer satisfies the above formula (1), both the amount of toner discharged when the sponge layer dents and the amount of suction when the sponge layer recovers, and enters and stays in the sponge layer of the toner supply roller. The toner in the developing chamber and the toner in the developing chamber are smoothly exchanged, and a toner supply roller having excellent characteristics can be obtained.

  Further, if the sponge layer satisfies the relationship of the above formula (2), the sponge layer that is dented at the nip portion is easy to return to the original shape, and the peripheral speed of the toner supply roller, the toner supply roller, and the toner carrier Although depending on the relative peripheral speed difference, the variation in the contact pressure at the nip portion is reduced, and the frictional charging of the toner can be made more stable.

  As described above, the toner supply roller of the present invention has a configuration including the cylindrical core metal 21 and the cylindrical sponge layer 22 formed concentrically with the core metal 22 on the outer periphery thereof. The surface shape of the sponge layer 22 may be cylindrical or may have a groove parallel to the longitudinal direction of the toner supply roller, and the cross-sectional shape perpendicular to the longitudinal direction may have a gear shape.

  In the toner supply roller of the present invention, it is preferable that the cells of the sponge layer 22 are open on the outer peripheral surface of the toner supply roller (the surface in contact with the toner carrier), and the cells communicate with each other. With the communication configuration, when the sponge layer dents and recovers at the nip portion, the toner can be easily discharged or sucked.

  The cell diameter is preferably 200 to 800 μm, and more preferably 400 to 600 μm. When the cell diameter is 200 μm or more, the resistance when the toner and air are discharged and sucked is reduced, and the toner is discharged and sucked efficiently. Further, it is preferable that the cell diameter is 800 μm or less because when the sponge layer is deformed at the nip portion, the air discharge speed and the flow rate during suction increase, and the toner discharge speed increases.

  The rubber forming the sponge layer is not particularly limited, but in general, natural rubber, EPDM, latex sponge, polyurethane and the like are preferably used. Among these, polyurethane is preferable because it can easily realize softness that does not deteriorate the toner. Polyesters and polyethers can be used as the polyurethane, but polyesters tend to have a relatively high tan δ and polyethers tend to have a low tan δ.

  The hardness of the sponge layer of the toner supply roller of the present invention is 50 mm in length and 10 mm in width when the diameter of the core bar is 5 mm, the outer shape of the sponge layer is 16 mm, and the outer diameter is 16 mm so as not to deteriorate the toner. What is a load when it compresses 1.0 mm with a flat plate of 50 g / mm-400 g / mm is preferable, and what is 80-300 g / mm is more preferable.

  The toner supply roller of the present invention can be prepared by a known method. For example, a cored bar made of metal is usually used as the cored bar, but may be other types.

  As a method for forming the sponge layer, a method of directly forming on the outer periphery of the metal core using the rubber raw material composition containing the rubber raw material and the foaming agent is preferably used, but other methods may be adopted.

  For example, when forming a polyurethane sponge layer, polypropylene oxide and / or polyethylene oxide is added to starting materials such as glycerin, trimethylolpropane, triethanolpropane, triethanolamine, hexanetriol, pentaerythritol, propylene glycol, and ethylene glycol. Polyether polyols or polyols such as adipates such as ethylene adipate, ethylene butylene adipate, butylene adipate, hexylene adipate, diethylene glycol adipate, and polyester polyols such as caprolactone ester, and tolylene diisocyanate (2,4-TDI or 2,6-ТDI), crude TDI (such as a mixture of 2,4-TDI and 2,6-ТDI), 4, 4-diphenylmethane diisocyanate (MDI), crude MDI (polymeric MDI), alicyclic polyisocyanates having 2 to 18 carbon atoms, and mixtures and modified products of these polyisocyanates such as prepolymers obtained by partially reacting with polyols Mixing with isocyanate compounds such as polymers, if necessary, foaming agents such as water, silicone foam stabilizers, resination catalysts such as tertiary amines, foaming catalysts, dipropylene glycol, diethanolamine, triethanolamine A polyurethane raw material composition appropriately blended with a crosslinking agent such as trimethylolpropane can be used.

  In the toner supply roller of the present invention, for example, a core metal is set in a mold, and the rubber raw material composition is foam-molded in the mold to form a sponge layer concentrically with the core metal on the outer periphery of the core metal. do it. In this case, molding conditions such as molding pressure and molding temperature (mold temperature) may be appropriately determined according to the type of rubber raw material and foam used, the composition of the rubber raw material composition, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. In this example, tan δ was measured and the obtained toner supply roller was evaluated by the following method.

[Measurement method of tan δ]
The sponge part of the toner supply roller of the example or comparative example was cut into 5 mm widths, and this was sandwiched between parallel plate having a diameter of 16 mm of a viscoelasticity measuring device RSA-II (Rheometrics Co., Ltd .; trade name) and compressed by 1 mm. Further, tan δ was measured while applying a displacement of a sine wave having an amplitude of 0.5 mm and a frequency of 10 Hz to this and raising the temperature from 0 ° C. to 40 ° C. at a rate of 3 ° C./min.

[Evaluation method of toner supply roller]
The toner supply roller of Example or Comparative Example is mounted on a cartridge of a laser beam printer, Color Laser Shot 2040 (manufactured by Canon Inc .; trade name), and printing test is performed using cyan toner in a 15 ° C., 10% RH environment. Went. The resulting image was visually inspected to evaluate drum fog and image.

(Example 1)
100 parts by weight of diethylene adipate ester polyol (manufactured by Nippon Polyurethane Industry Co., Ltd., N-1004; trade name, molecular weight 2500, hydroxyl value 41), 1.2 parts by weight of water, 1 part by weight of trimethylolpropane, resinization catalyst 0.9 parts by mass of TOSO Co., Ltd., TEDA-L33; trade name, mixture of 33% triethylenediamine 67% dipropylene glycol), foaming catalyst (Tosoh Corporation, TOYOCAT-ET; trade name, 70% bis (dimethylaminomethyl) ether 30% mixture) and a silicone foam stabilizer (GE Toshiba Silicone Co., Ltd., SE-232; trade name) 2 parts by mass and sufficiently stirred liquid Was made. The hydroxyl value of this liquid was 127. 19.8 masses of 2,4-TDI (manufactured by Nippon Polyurethane Industry Co., Ltd., T-100; trade name, NCO content of about 48.2%) so that the isocyanate index becomes 100 per 100 mass parts of the liquid. The parts were mixed with a low-pressure urethane foaming machine, and 600 g was discharged into a foaming box having a bottom surface of 250 mm × 250 mm and a sufficient height to obtain a free foam.

  This foam was subjected to a crushing treatment to be communicated, and aged in a constant temperature layer at 100 ° C. for 30 minutes. This free foamed body was cut into a 30 mm × 30 mm × 225 mm rectangular parallelepiped, a hole with a diameter of 5 mm was made in the longitudinal direction, a diameter of 5.0 mm with a hot melt adhesive applied, a length of 285 mm, and D cut was applied to one end. A cored bar was inserted and heated to bond the cored bar and the foam. Next, the foam part is cut so as to have a diameter of 16 mm concentric with the core metal, and the end part is cut so that the length in the longitudinal direction of the foam part is 215 mm, and a sponge made of polyester polyurethane (1). A toner supply roller having a predetermined dimension and having a layer was obtained.

  The toner supply roller was evaluated by measuring tan δ of the sponge layer of the toner supply roller by the method described above.

  Further, a flat plate having a length of 50 mm and a width of 10 mm is brought into contact with the sponge layer of the toner supply roller so that the central axis of the core of the toner supply roller and the center line in the width direction of the flat plate are parallel to each other. The hardness of the sponge layer of this toner supply roller was evaluated by measuring the load when pressed at a speed of 1.0 min / min and compressed by 1.0 mm. The obtained hardness was 200 g / mm.

  Further, the average cell diameter (average value of 10 cells) of the sponge layer of the toner supply roller at a magnification of 35 times using a scanning electron microscope (manufactured by JEOL Ltd., LV-SEM JSM-5910LV; trade name) ) Was measured. The average cell diameter obtained was 400 μm.

  The obtained results are summarized and shown in FIG.

  The tan δ of the sponge layer of the toner supply roller of this example satisfies the relationship of the above formulas (1) and (2), there is almost no drum fogging, and the image is good with no unevenness.

Example 2
100 parts by mass of glycerol-initiated EO / PO polyether polyol (Mitsui Takeda Chemical Co., Ltd., EP950; trade name, molecular weight 5000, hydroxyl value 33.9), 1.2 parts by mass of water, 1 part by mass of dipropylene glycol , 0.9 parts by mass of resinification catalyst (TESO-L33; trade name, 33% triethylenediamine 67% dipropylene glycol) manufactured by Tosoh Corporation, and foaming catalyst (TOYOCAT-ET, manufactured by Tosoh Corporation) Mixed with 0.05 parts by mass of a trade name, 70% bis (dimethylaminomethyl) ether 30% mixture), and 2 parts by mass of a silicone foam stabilizer (manufactured by Nippon Unicar Co., Ltd., L-582; trade name). Liquid was produced. The hydroxyl value of this liquid was 116. 4,4-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MT; trade name, NCO content 33.6%), crude MDI (Nippon Polyurethane) Industrial Co., Ltd., MR-200; trade name, NCO content 30.8%), 2,4-TDI (Nippon Polyurethane Industry Co., Ltd., T-100; trade name, NCO content about 48.2%) Is a mixed isocyanate solution with an NCO content of 38.6% mixed at a mass ratio of 30:30:40. 22.5 parts by mass are mixed with a low-pressure urethane foaming machine, and the bottom is 250 mm x 250 mm with a sufficient height. 600 g was discharged to obtain a free foam.

  A toner supply roller having a predetermined size having a sponge layer made of polyether-based polyurethane (1) was prepared in the same manner as in Example 1 except that this free foam was used. The toner supply roller was evaluated by measuring tan δ, the hardness of the sponge layer, and the average cell diameter of the sponge layer. The obtained results are summarized and shown in FIG.

Example 3
100 parts by mass of glycerin-initiated EO / PO polyether polyol (manufactured by Sanyo Chemical Industries, Ltd., FA-908; trade name, molecular weight 7000, hydroxyl value 24.3), 1.2 parts by mass of water, resinization catalyst ( Tosoh Co., Ltd., TEDA-L33; trade name, mixture of 33% triethylenediamine 67% dipropylene glycol 0.9 parts by mass, foaming catalyst (Tosoh Co., Ltd., TOYOCAT-ET; trade name, 70 % Bis (dimethylaminomethyl) ether 30% mixture) and a silicone foam stabilizer (manufactured by Nippon Unicar Co., Ltd., L-582; trade name) 2 parts by mass were mixed to prepare a sufficiently stirred liquid. . The liquid had a hydroxyl value of 100. 21.0 parts by mass of mixed isocyanate of crude MDI and TDI (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate 1028; trade name, NCO content 35.7%) so that the isocyanate index is 100 per 100 parts by mass of the liquid Were mixed with a low-pressure urethane foaming machine, and 600 g was discharged into a foaming box having a bottom surface of 250 mm × 250 mm and a sufficient height, to obtain a free foam.

  A toner supply roller having a predetermined size having a sponge layer made of polyether polyurethane (2) was produced in the same manner as in Example 1 except that this free foam was used. The toner supply roller was evaluated by measuring tan δ, the hardness of the sponge layer, and the average cell diameter of the sponge layer. The obtained results are summarized and shown in FIG.

Comparative Example 1
Diethylene adipate ester polyol (Nippon Polyurethane Industry Co., Ltd., N-150; trade name, molecular weight 1000, hydroxyl value 112) 100 parts by mass, water 1.2 parts by mass, trimethylolpropane 2 parts by mass, resinization catalyst 0.9 parts by mass of TOSO Co., Ltd., TEDA-L33; trade name, mixture of 33% triethylenediamine 67% dipropylene glycol), foaming catalyst (Tosoh Corporation, TOYOCAT-ET; trade name, 70% bis (dimethylaminomethyl) ether 30% mixture) and a silicone foam stabilizer (GE Toshiba Silicone Co., Ltd., SE-232; trade name) 2 parts by mass were mixed and sufficiently stirred. Was made. The hydroxyl value of this liquid was 205. 31.8 masses of 2,4-TDI (manufactured by Nippon Polyurethane Industry Co., Ltd., T-100; trade name, NCO content of about 48.2%) so that the isocyanate index is 100 per 100 mass parts of the liquid. The parts were mixed with a low-pressure urethane foaming machine, and 600 g was discharged into a foaming box having a bottom surface of 250 mm × 250 mm and a sufficient height to obtain a free foam.

  A toner supply roller having a predetermined size having a sponge layer made of polyester polyurethane (2) was prepared in the same manner as in Example 1 except that this free foam was used, and tan δ of the sponge layer of this toner supply roller was produced. Then, the hardness of the sponge layer and the average cell diameter of the sponge layer were measured, and the toner supply roller was evaluated. The obtained results are summarized and shown in FIG.

  The image was very good, but there was much drum cover.

Comparative Example 2
100 parts by mass of glycerol-initiated EO / PO polyether polyol (molecular weight 9000, hydroxyl value 18.5) manufactured by Mitsui Takeda Chemical Co., Ltd., 1.2 parts by mass of water, resinized catalyst (manufactured by Tosoh Corporation, TEDA) -L33: Trade name, 0.9 parts by mass of a mixture of 33% triethylenediamine 67% dipropylene glycol), foaming catalyst (TOYOCAT-ET, manufactured by Tosoh Corporation); trade name, 70% bis (dimethylaminomethyl) A liquid obtained by mixing 0.05 part by mass of a 30% ether mixture) and 2 parts by mass of a silicone foam stabilizer (manufactured by Nippon Unicar Co., Ltd., L-582; trade name) was prepared. The liquid had a hydroxyl value of 94.5. 19.8 parts by mass of a mixed isocyanate of crude MDI and TDI (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate 1028; trade name, NCO content 35.7%) so that the isocyanate index is 100 per 100 parts by mass of the liquid Were mixed with a low-pressure urethane foaming machine, and 600 g was discharged into a foaming box having a bottom surface of 250 mm × 250 mm and a sufficient height, to obtain a free foam.

  A toner supply roller having a predetermined size having a sponge layer made of polyether polyurethane (3) was prepared in the same manner as in Example 1 except that this free foam was used. The toner supply roller was evaluated by measuring tan δ, the hardness of the sponge layer, and the average cell diameter of the sponge layer. The obtained results are summarized and shown in FIG.

  There was almost no drum cover, but horizontal stripes appeared in the image.

  According to the present invention, it is possible to provide a toner supply roller that can maintain normal chargeability of the toner and obtain an excellent image.

FIG. 4 is a schematic diagram illustrating an example of a developing device in which the toner supply roller of the present invention can be mounted. It is a schematic diagram showing an example of a toner supply roller of the present invention. It is a figure which shows the measurement result of tan-delta of the sponge layer of the toner supply roller of a present Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Latent image carrier 2 Toner carrier 3 Control member 4 Toner supply roller 21 Core metal 22 Sponge layer

Claims (2)

In order to visualize the latent image formed on the latent image carrier, a toner carrier disposed opposite to the latent image carrier, supplying toner to the toner carrier, and removing excess toner A toner supply roller that contacts the toner carrier while moving relative to the toner carrier, and a restriction that is disposed in contact with the toner carrier to regulate the amount of toner supplied on the toner carrier. A toner supply roller used in a developing device having a member, wherein tan δ measured at 10 Hz is a temperature (t ° C.) in a range of 0 to 40 ° C. A toner supply roller having a sponge layer satisfying the relationship 2).
tan δ <0.5-t / 200 (1)
tan δ> 0.05−t / 1600 (2)   2. The toner supply roller according to claim 1, wherein the sponge layer is made of polyurethane.

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