JP5102991B2 - Toner supply roller and manufacturing method thereof - Google Patents

Description

  The present invention relates to a toner supply roller used in a developing device of an image forming apparatus and a method for manufacturing the same.

  Image forming apparatuses such as copying apparatuses, image recording apparatuses, printers, and facsimile machines are provided with a developing device that develops an electrostatic latent image formed on a latent image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric. It is done. The developing device includes, for example, a developing roller that closes an opening of a developing container that stores predetermined toner (developer), is partially exposed, and is disposed so as to face the latent image carrier at the exposed portion. The toner stored in the developing container is supplied to the latent image carrier. In the developing container, a toner supply roller that supplies toner to the surface of the developing roller, a blade that removes excess toner and forms a thin film of toner on the developing roller, and the like are provided. The toner supply roller is required to have low hardness, that is, flexibility in order to supply toner to the surface of the developing roller and scrape unnecessary parts at the same time to supply a constant amount of toner.

  In such a developing device, when left in a low temperature and low humidity environment for a long period of time, it becomes difficult to control the toner amount on the surface of the developing roller with a blade alone due to toner charge-up, etc. The resulting image defect may occur. Therefore, it is conceivable to reduce the resistance (conductivity) of the toner supply roller.

  On the other hand, as an elastic roller having a low-resistance polyurethane sponge layer, one using an ionic conductive agent is known (Patent Document 1). An elastic roller containing an ionic conductive agent in the polyurethane sponge layer has advantages such as low roller resistance unevenness and low voltage dependency.

  However, when the resistance of the polyurethane sponge layer is reduced by an ionic conductive agent, the environmental dependency may increase, and it is difficult to obtain the same resistance under each environment.

It is known to use carbon black, aluminum oxide, or the like as a method for reducing resistance so as to reduce environmental dependency. Among them, as an excellent method, DBP oil absorption amount, 100cm ² / 100g~500cm ² / 100g toner supply roller containing 0.5% to 3.0% of carbon black in the polyurethane sponge layer has been proposed (Patent Document 2).

However, the material surface such as the molecular weight of the polyol component, the ratio of ethylene oxide uniform and the composition of the isocyanate component and the molding method of the toner supply roller have not been studied, and the polyurethane sponge layer that can appropriately suppress environmental dependency unknown.
JP 11-292948 A Japanese Patent Laid-Open No. 10-268627

  SUMMARY OF THE INVENTION An object of the present invention is to provide a toner supply roller having a low resistance and a stable electric resistance value regardless of the environment. It is another object of the present invention to provide a toner supply roller that can perform toner supply and scraping well and uniformly, suppress an increase in toner consumption, and obtain an image with reduced density unevenness. .

The present invention relates to a toner supply roller having a cored bar and a polyurethane sponge layer provided on the outer periphery of the cored bar, wherein the polyurethane sponge layer contains a polyether polyol (B) and a polyether polyol (C). Obtained by using the component (A), the polyisocyanate component (D), the catalyst, the conductive agent, and the foaming agent, and the polyether polyol (C) is in the range of 1% by mass to 30% by mass in the polyol component (A). The toner supply roller is characterized in that the cell opening ratio on the outer peripheral surface of the polyurethane sponge layer is 20% or more. The polyether polyol (B) is a copolymer having an ethylene oxide unit at the terminal, and the content of the ethylene oxide unit is 5% by mass or more and 30% by mass or less, and the mass average molecular weight is 2500 or more and 7500 or less. It is.
Polyether polyol (C) is a polymer comprising units of the polyether polyol represented by the general formula (1), mass average molecular weight of 1000 to 4,000 polyether polyols.
HO— (C ₂ H ₄ O) ₁ —H (1)
(In the formula, l represents any integer of 1 or more.)

  The toner supply roller of the present invention is to provide a toner supply roller having a low resistance and a stable electric resistance value regardless of the environment. In addition, toner can be supplied and scraped well and uniformly, an increase in toner consumption can be suppressed, and an image with reduced density unevenness can be obtained.

The toner supply roller of the present invention is a toner supply roller having a cored bar and a polyurethane sponge layer provided on the outer periphery of the cored bar, wherein the polyurethane sponge layer comprises a polyether polyol (B) and a polyether polyol (C). It is obtained using a polyol component (A), a polyisocyanate component (D), a catalyst, a conductive agent, and a foaming agent, and the polyether polyol (C) is 1% by mass to 30% by mass in the polyol component (A). It is included in the following range, and the cell opening ratio on the outer peripheral surface of the polyurethane sponge layer is 20% or more. The polyether polyol (B) is a copolymer having an ethylene oxide unit at the terminal, containing an ethylene oxide unit in the range of 5% by mass to 30% by mass, and a mass average molecular weight of 2500 to 7500. It is. Polyether polyol (C) is a polymer comprising units of the polyether polyol represented by the general formula (1), mass average molecular weight of 1000 to 4,000 polyether polyols.
HO— (C ₂ H ₄ O) ₁ —H (1)
(In the formula, l represents any integer of 1 or more.)

[Polyol component (A)]
The polyol component (A) used for forming the polyurethane sponge layer of the toner supply roller of the present invention contains a polyether polyol (B) and a polyether polyol (C). The polyol component has a polyether polyol having a weight average molecular weight in a different range, thereby suppressing the decrease in the reaction rate of the urethanization reaction, sufficiently forming cells and forming sufficient openings. Make it possible.

[Polyether polyol (B)]
The polyether polyol (B) is a copolymer containing an ethylene oxide unit at the terminal. By having an ethylene oxide unit at the terminal, the urethanization reaction can be promoted, and a urethane sponge layer can be molded by a mold. The ethylene oxide unit refers to —C ₂ H ₄ O—, and the end of the polyether polyol (B) has a hydrogen atom or a hydroxyl group bonded to the ethylene oxide unit, resulting in HO—C ₂ H ₄ O— or —C ₂ H _4. It is O-H. Content of the ethylene oxide unit in polyether polyol (B) is 5 to 30 mass%. If the content of the ethylene oxide unit of the polyether polyol (B) is 5% by mass or more, the urethanization reaction can be promoted, and a good urethane sponge layer can be formed in the molding with a molding die, and 30% by mass. If it is below, the fall of the cell opening property of the urethane sponge layer surface by promotion of resinification reaction can be suppressed. When the content of the ethylene oxide unit in the polyether polyol (B) is 10% by mass or more and 25% by mass or less, the above effect can be more remarkably obtained, which is preferable.

  Examples of the polyether polyol (B) include a copolymer obtained by addition polymerization of ethylene oxide and another monomer, for example, an oxide such as propylene oxide, using a reaction initiator. Examples of the reaction initiator include glycerin, trimethylolpropane, ethylene glycol, propylene glycol, pentaerythritol, sorbitol and the like. The amount of ethylene oxide used can be appropriately determined in consideration of characteristics such as the molecular weight of the copolymer as a product.

  Moreover, it is preferable that the average number of hydroxyl groups of polyether polyol (B) is 2-4. If the average number of hydroxyl groups is 2 or more, the generation of compression set can be suppressed in the urethane sponge layer even in a high temperature and high humidity environment. If the average number of hydroxyl groups is 4 or less, the urethane sponge has high hardness. Can be suppressed.

  Furthermore, the polyether polyol (B) has a weight average molecular weight of 2500 to 7500. If the mass average molecular weight is 2500 or more, the resulting urethane sponge layer can be prevented from having high hardness. If the mass average molecular weight is 7500 or less, it is easy to mix with the polyisocyanate and can be mixed uniformly, and it is easy to handle at the time of molding. It can be performed. The mass average molecular weight of the polyether polyol is more preferably 3000 to 5000.

  Polyether polyol (B) can use the said polyether polyol 1 type or in combination of 2 or more types.

  The polyether polyol (B) is preferably contained in the polyol component (A) in the range of 84 to 70% by mass, for example.

  Specific examples of such polyether polyol (B) include commercially available EP550N (manufactured by Mitsui Takeda Chemical Co., Ltd.), EP950 (manufactured by the same company), and the like.

[Polyether polyol (C)]
The polyether polyol (C) is a polymer having an ethylene oxide unit at the terminal. By having an ethylene oxide unit at the terminal, the urethanization reaction can be promoted, and a urethane sponge layer can be molded by a mold. The end of the polyether polyol (C) is similar to the end of the polyether polyol (B), in which an oxygen atom or a hydroxyl group is bonded to the terminal ethylene oxide unit, and HO—C ₂ H ₄ O— or —C ₂ H ₄ O. -H.

  As the polyether polyol (C), the general formula (1)

HO— (C ₂ H ₄ O) ₁ —H (1)
In is a homopolymer of polyethylene oxide polyols represented. The polyethylene oxide polyol represented by the general formula (1) has a hydroxyl group bonded to the terminal ethylene oxide unit, has excellent compatibility with water, can promote the urethane reaction, and the cell is sufficiently formed. A molded urethane sponge can be formed.

The content of the ethylene oxide unit in the polyether polyol (C) which is such a polymer is 100% by mass including the terminal ethylene oxide unit. When the content of the ethylene oxide unit in the polyether polyol (C) is 100% by mass , the urethanization reaction can be promoted, and the urethane sponge layer can be molded by a molding die.

  The polyether polyol (C) has a mass average molecular weight of 1000 or more and 4000 or less. If the mass average molecular weight is 1000 or more, the cell opening ratio is high, and a low-grade urethane sponge layer can be formed. If it is 4000 or less, the increase in viscosity is suppressed and workability and stirring and mixing properties are reduced. Can be suppressed. The mass average molecular weight of the polyether polyol is more preferably 3000 to 5000.

  The polyether polyol (C) is contained in the polyol (A) in the range of 1% by mass to 30% by mass. If the content of the polyether polyol (C) is 1% by mass or more, open cells can be formed during the urethanization reaction, cells can be sufficiently formed, and cells on the surface of the urethane sponge layer can be opened. Become. In other words, it is not necessary to increase the foaming pressure in the mold by increasing the content of the foaming agent such as water in order to sufficiently form and open cells up to the surface area, thereby generating by-products of aromatic polyurea. Can be suppressed. Furthermore, the reaction rate of the polyol component (A) and the polyisocyanate component (D) is slowed down, and mixing of the raw materials becomes easy. Then, the cells can be sufficiently formed, the molding with a small mold can be performed, and the cells existing on the surface can be broken to increase the opening ratio of the surface of the polyurethane sponge layer.

  Specific examples of such polyether polyol (C) include MF-19T (manufactured by Mitsui Takeda Chemical Co., Ltd.) and EP505S (manufactured by the same company).

  The polyol component (A) preferably contains 85 to 100% by mass of the polyether polyol (B) and the polyether polyol (C) in total. Furthermore, in addition to these polyether polyols, the polyol component (A) may contain other polyols such as polyether polyols other than those described above.

[Polyisocyanate component (D)]
The polyisocyanate component (D) used in the polyurethane sponge layer is not particularly limited, and specifically, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, etc. Examples thereof include aliphatic polyisocyanates and derivatives thereof, alicyclic polyisocyanates such as isophorone diisocyanate, and derivatives thereof. Moreover, these can also be prepolymerized with a polyol and used. These can be used alone or in combination of two or more, but toluene diisocyanate (TDI) is particularly preferred. TDI is preferably contained in the polyisocyanate component (D) in an amount of 20% by mass or more. When the content of TDI in the polyisocyanate component (D) is 20% by mass or more, a decrease in the air permeability of the urethane sponge can be suppressed, and an increase in viscosity can be suppressed and mixing with the polyol component (A) can be performed. It can be done easily.

  The isocyanate index of the polyisocyanate component (D) is preferably 70 or more and 120. If the isocyanate index is 70 or more, urethane formation is promoted and a urethane sponge layer containing sufficient polyurethane can be formed. Moreover, if the isocyanate index is 120 or less, a low-hardness urethane sponge layer can be obtained.

  Here, the isocyanate index is represented by an equivalent ratio of NCO groups to active hydrogen groups (NCO group equivalent / active hydrogen group equivalent) × 100 in the reaction with isocyanate.

[Conductive agent]
Examples of the conductive agent include filler-based conductive materials such as carbon black, metal powder, and metal oxide powder, and carbon black is particularly preferable. The carbon black, DBP (butyl phthalate: JIS K6752) oil absorption, 150 cm ^3/100 g or more as 600cm is ^3/100 g or less is preferable. To obtain conductivity, DBP oil absorption amount, 400 cm ^3/100 g or more 600cm and a ^3/100 g or less, and a BET specific surface area of it is more preferably not more than 1000 m ² / g or more 1400 m ² / g. DBP oil absorption amount of carbon black, if 150 cm ^3/100 g or more, a polyurethane sponge layer is obtained having a sufficient conductivity, it is possible to reduce the content of carbon black. Further, DBP oil absorption of the carbon black is equal to or less 600 cm ^3/100 g, it is possible to suppress the thickening of the polyurethane sponge layer material, to suppress the high hardness of the workability decreases and the resulting toner supply roller .

  Here, the value by the measuring method according to JIS K6217-4: 2001 can be employ | adopted for the said DBP oil absorption. Moreover, the numerical value by the measuring method according to JISK6217-2: 2001 can be employ | adopted for a BET specific surface area.

  As a usage-amount of the said carbon black, 0.5-10 mass parts can be mentioned as a preferable range with respect to 100 mass parts of polyether polyol, More preferably, it is 1-3 mass parts.

[catalyst]
A known urethanization catalyst can be used as the catalyst for promoting the reaction between the polyol component (A) and the polyisocyanate component (D). Specifically, triethylenediamine, bis (dimethylaminoethyl) ether, N, N, N ′, N′-tetramethylhexanediamine, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5 -Amine catalysts such as diazabicyclo (4,3,0) nonene-5, 1,2-dimethylimidazole, N-ethylmorpholine, N-methylmorpholine, tin octylate, tin oleate, dibutyltin dilaurate, dibutyltin di Carboxylic acid for reducing initial activity of organometallic catalysts such as acetate, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetrakis (2-ethylhexyloxy) titanium, the amine catalyst and organometallic catalyst An acid salt catalyst such as a salt, formate, octylate or borate can be used. These catalysts can be used alone or in combination of two or more. As a usage-amount of a catalyst, 0.01-5 mass parts is preferable with respect to 100 mass parts of polyether polyol, More preferably, it is 0.01-3 mass parts.

[Foaming agent]
As a foaming agent for obtaining a sponge body by urethanation reaction between the polyol component (A) and the polyisocyanate component (D), water is particularly suitable because it reacts with the polyisocyanate to generate carbon dioxide. Used for. Chlorofluorocarbons (such as HFC-134A) and hydrocarbons (such as cyclopentane) developed for the purpose of protecting the global environment can also be used. These can be used alone or in combination of two or more. Moreover, the foaming agent by physical foaming mixed with the said raw materials, such as the gas which does not react with the said raw material, may be sufficient.

  As a usage-amount of a foaming agent, in the case of water, for example, 0.5-5 mass parts is preferable with respect to 100 mass parts of polyether polyol, More preferably, it is 1.0-3.0 mass parts.

[Other materials]
In order to obtain a polyurethane sponge layer, a foam stabilizer can be used as needed. Examples of foam stabilizers include water-soluble polyether siloxane from polydimethylsiloxane and ethylene oxide / propylene oxide copolymer, sodium salt of sulfonated ricinoleic acid, and a mixture of these with polysiloxane / polyoxyalkylene copolymer. Can do. These can be used alone or in combination of two or more. Among these foam stabilizers, water-soluble polyether siloxane from polydimethylsiloxane and an ethylene oxide / propylene oxide copolymer can be mentioned as a preferable one.

  As other auxiliary agents, an appropriate amount of a crosslinking agent, a flame retardant, a colorant, an ultraviolet absorber, an anti-aging agent, an antioxidant, a conductivity-imparting agent and the like can be used as necessary.

[Create polyurethane sponge layer]
In order to prepare a polyurethane sponge layer, the above-mentioned polyol component (A), polyisocyanate component (D), catalyst, conductive agent, foaming agent, and if necessary, a foam stabilizer and other auxiliaries are mixed, and a liquid polyurethane raw material Get. Although there is no restriction | limiting in particular about the temperature and time at the time of mixing each said raw material, Mixing temperature is 10-70 degreeC normally, Preferably it is the range of 20-50 degreeC, and mixing time is 1 second-10 minutes normally, Preferably, it is about 3 seconds to 5 minutes.

  Subsequent foam hardening is preferably performed using a mold. As the mold, a mold having a mold cavity having a surface with a contact angle of 85 degrees or more measured using ethylene glycol is preferable. The surface of the molding cavity having an ethylene glycol contact angle of 85 ° C. or more has an incompatibility or surface tension effect with the liquid polyurethane raw material, and is the portion closest to the molding cavity surface of the cell caused by foaming in the polyurethane raw material That is, the absence of the polyurethane raw material occurs in the central portion of the cell where the cell wall thickness is the smallest. As a result, a cell opened to the outside can be formed on the surface of the formed polyurethane sponge layer. If the contact angle of ethylene glycol on the surface of the molding cavity is 85 ° or more, the effect of the incompatible action or surface tension action with the polyurethane raw material can be sufficiently exerted, and the cell opening having a uniform and sufficient opening diameter. Can be formed. Furthermore, the adhesiveness of the cured polyurethane sponge layer can be suppressed and the molded product can be easily released.

  The shape of the mold may be any shape, but a cylindrical mold is preferable. By using a cylindrical mold, if necessary, a core metal coated with an adhesive is installed, the liquid polyurethane raw material is injected into the core metal and a molding cavity formed in the cylindrical mold, and then heat-cured and foamed. Thus, a polyurethane sponge layer can be formed on the outer periphery of the cored bar. Thereafter, the toner supply roller in which the cored bar and the polyurethane sponge layer are integrated can be obtained by demolding.

  Further, the mold is not limited to a cylindrical shape, and may have a shape for obtaining a sheet-like polyurethane sponge body. When such a sheet-like polyurethane sponge mold is used, it can be joined around the cored bar.

  The cored bar used in the toner supply roller of the present invention may be any of iron, aluminum, etc. having a columnar shape, a cylindrical shape or the like. The outer diameter of the cored bar can be set to 2 mm or more and 10 mm or less, for example.

  As a method for joining the core metal and the polyurethane sponge layer, a method of integrating and curing using the cylindrical mold as described above, a method of bonding the core metal after molding the raw material mixture into a predetermined shape, or the like is used. Can do. In either method, an adhesive layer can be provided between the cored bar and the polyurethane sponge layer as necessary, and a known material such as an adhesive or a hot melt sheet can be used as the adhesive layer.

[Polyurethane sponge layer]
The polyurethane sponge layer of the toner supply roller of the present invention has a plurality of cell openings communicating with the inside on the surface, and the cell opening ratio of the outer peripheral surface is 20% or more. A more preferable cell opening ratio is 30% to 60%. When the cell opening ratio of the polyurethane sponge layer is 20% or more, the toner can be sufficiently contained, a sufficient amount of toner can be supplied to the developing roller, and a good image can be obtained.

  The cell aperture ratio is obtained by taking a surface image using a real-time scanning laser microscope (manufactured by Lasertec Co., Ltd., 1LM21DW-1), performing binarization processing by image analysis, obtaining the cell opening area, (Cell opening area ratio [%] = cell opening area / image range × 100), a method for obtaining the cell opening area ratio [%] (Japanese Patent Laid-Open No. 2006-187940), or a CCD video camera manufactured by Hilox Co., Ltd. Used to take a photograph at a magnification of 40 to 60 times, calculate the area of the cell opening of the photographic image, and divide by the area of the entire photographic image to obtain the cell opening ratio (Japanese Patent Laid-Open No. 2004-021212), etc. The measured value can be adopted.

Further, the polyurethane sponge layer, when the respective atmospheric pressure and 125Pa vertical pair of side in the axial direction, airflow rate per unit area of the side surface is 0.8L / cm ² / min or more 3L / cm ² / min The following range is preferable. If the air flow rate is 0.8 L / cm ² / min or more, the occurrence of clogging with toner can be suppressed even after long-term use. For this reason, toner deterioration due to an increase in the hardness of the roller can be suppressed. Further, accumulation of toner inside can be suppressed, the core metal side can be prevented from becoming hard, and the polyurethane sponge on the low altitude surface side can be stretched to prevent the polyurethane sponge layer from being damaged. Further, such a polyurethane sponge layer can be easily formed if the air flow rate is 3 L / cm ² / min or less. A polyurethane sponge layer having an air flow rate in this range improves toner supply.

  Such an air flow rate can be a value measured using the measuring apparatus shown in FIG. The measuring apparatus shown in FIG. 2 is press-fitted into a cylinder 4 having an inner diameter slightly smaller than the outer diameter of the toner supply roller of the measured object, for example, an inner diameter of 90% or less, more preferably 95% or less of the outer diameter of the toner supply roller. The opening at one end of the cylinder 4 is opened to the atmosphere, the opening at the other end is sealed, and the vacuum pump 6 is connected to the sealed space via the flow meter 5. Next, a pressure gauge 7 is connected to the sealed space, the vacuum pump 6 is operated so that the pressure in the sealed space becomes 125 Pa, and the air flow rate at that time is measured with a flow meter. By dividing the obtained value by the cross-sectional area of the side surface perpendicular to the axial direction of the polyurethane sponge layer, the air flow rate per unit area of the side surface is obtained.

  The thickness of the polyurethane sponge layer is preferably 1 to 20 mm, and more preferably 2 to 12 mm. When the thickness is within these ranges, the toner supply roller has good toner transportability.

  Such a polyurethane sponge layer has low hardness and flexibility, and has a function of supplying toner to a developer carrying member such as a developing roller and scraping off an unnecessary amount.

[Toner supply roller]
The toner supply roller of the present invention is not particularly limited as long as it has the polyurethane sponge layer, and may have other functional layers in addition to the adhesive layer as long as it does not impair the function of the polyurethane sponge layer. Good.

  An example of the toner supply roller of the present invention is the one shown in the perspective view of FIG. The toner supply roller shown in FIG. 1 includes a cylindrical cored bar 2 and a polyurethane sponge layer 3 provided around the cored bar 2 except for both ends of the cored bar 2.

The toner supply roller of the present invention will be specifically described below, but the technical scope of the present invention is not limited to these.
[Examples 1-3, Reference Example 4, Examples 5-8, Comparative Examples 1-4]
1 part by mass of polyether polyol (B), (C), polyisocyanate, carbon black and foam stabilizer SRX274C (silicone foam stabilizer manufactured by Toray Dow Corning Silicone Co., Ltd.) in parts by mass shown in Tables 1 and 2 , TOYOCAT-ET (tertiary amine catalyst manufactured by Tosoh Corporation) 0.1 part by mass as a catalyst, TOYOCAT-L33 (tertiary amine catalyst manufactured by Tosoh Corporation) 0.5 part by mass, water 2.0 as a blowing agent The mass parts were mixed and stirred at 25 ° C. so that the NCO index was 90. This mixture was poured into a pipe-shaped mold having an inner diameter of 15 mm into which a metal shaft having a diameter of 5 mm was inserted so that the foam density would be 0.10 g / cm ³ and heated in an oven at 60 ° C. for 30 minutes. Foam cured. Thereafter, the mold was removed to prepare a toner supply roller.

  The cell opening property, air flow rate, and roller resistance on the skin surface of the obtained toner supply roller were measured by the following methods to evaluate image evaluation. The results are shown in Table 1.

In the table, 1) to 12) indicate the following.
1) Polyether polyol manufactured by Mitsui Takeda Chemical Co., Ltd. Weight average molecular weight 3100, containing 20% by mass of ethylene oxide unit at the end (OH value = 54 mg KOH / g, number of functional groups = 3)
2) Polyether polyol manufactured by Mitsui Takeda Chemical Co., Ltd. Contains a mass average molecular weight of 5000 and 15% by mass of an ethylene oxide unit at the end. (OH value = 34 mgKOH / g, number of functional groups = 3)
3) Polyether polyol manufactured by Mitsui Takeda Chemical Co., Ltd. Mass average molecular weight 2000. (OH number = 105 mg KOH / g, including polyether polyol unit represented by general formula (1), number of functional groups = 2)
4) Polyether polyol manufactured by Mitsui Takeda Chemical Co., Ltd. Contains a weight average molecular weight of 3500 and 70-80% by mass of ethylene oxide units randomly. (OH value = 51 mg KOH / g, number of functional groups = 3)
5) Polyisocyanate mixture (NCO% = 45, TDI / MDI = 80/20 (mass ratio)) manufactured by Mitsui Takeda Chemical Co., Ltd.
6) Polyisocyanate blend manufactured by Mitsui Takeda Chemical Co., Ltd. (NCO% = 40, TDI / MDI = 50/50 (mass ratio))
7) Ketjen Black International Co., Ltd. carbon black (DBP oil absorption = 360cm ³ / 100g, BET specific surface area = 800m ² / g)
8) Ketjen Black International Co., Ltd. carbon black (DBP oil absorption = 495cm ³ / 100g, BET specific surface area = 1270m ² / g)
9) The cell opening of the surface of the polyurethane sponge layer is obtained by using a real-time scanning laser microscope (manufactured by Lasertec Co., Ltd., 1LM21DW-1) to capture the surface image, and binarization processing is performed by image analysis. The area was determined, and the cell opening area ratio [%] was determined by the following formula (cell opening area ratio [%] = cell opening area / image range × 100). Cell opening ratio is 40% or more: ◯, cell opening ratio is 20-40%: Δ, cell opening ratio is less than 20%: x.
10) The air flow rate of the polyurethane sponge layer having an outer diameter of 14.8 mm was measured with the measuring apparatus shown in FIG. In the measuring apparatus shown in FIG. 2, the cylinder 4 having an inner diameter of 13.8 mm was used. The vacuum pump 6 is operated so that the pressure gauge 7 becomes 125 Pa, the value of the flow meter 5 at that time is read, and divided by the cross-sectional area perpendicular to the axial direction of the polyurethane sponge layer, the air flow per unit area Got.
11) A voltage of 200 V is applied between the cored bar and the stainless steel drum in a state where the toner supply roller is pressed against a stainless steel drum having an outer diameter of 30 mm so that the outer diameter of the produced toner supply roller is crushed by 1 mm. The current value was measured under an environment of 23 ° C./55% RH (N / N), and the resistance value was calculated according to Ohm's law.
12) A cartridge in which the produced toner supply roller was incorporated in a laser beam printer was allowed to stand at 10 ° C./15% RH (L / L) for 1 week, and image evaluation was performed. An hp color Laser Jet 4600 (manufactured by Hewlett-Packard Japan Ltd.) was used as an image evaluation machine. Fifty sheets were printed, and the fog at that time was observed and evaluated. Good image: ◯, no trouble in use: Δ, when defects are clearly recognized: x.

  From the results, the toner supply roller of the present invention has a low resistance, and a polyether polyol having an ethylene oxide unit and having a mass average molecular weight of 1,000 to 4,000 is mixed in a specific amount (as a foam breaker). It can be seen that not only the opening property is excellent, but also the image is good because the air flow rate is excellent. On the other hand, in the comparative example, the cell opening property of the skin surface is insufficient, the resistance is high, or the air flow rate is inferior, and the image is defective.

It is a perspective view showing an example of a toner supply roller of the present invention. FIG. 3 is a schematic configuration diagram showing a measuring device for measuring the air flow rate of the toner supply roller of the present invention.

Explanation of symbols

1 Toner supply roller 2 Core 3 Polyurethane sponge layer 4 Cylinder 5 Flow meter 6 Vacuum pump 7 Pressure gauge

Claims (7)

In a toner supply roller having a metal core and a polyurethane sponge layer provided on the outer periphery of the metal core, the polyurethane sponge layer contains a polyol component (A) containing a polyether polyol (B) and a polyether polyol (C). , Obtained using a polyisocyanate component (D), a catalyst, a conductive agent, and a foaming agent, the polyether polyol (C) is contained in the polyol component (A) in the range of 1% by mass to 30% by mass, A toner supply roller, wherein the cell opening ratio on the outer peripheral surface of the polyurethane sponge layer is 20% or more.
Polyether polyol (B): A polyether polyol having an ethylene oxide unit at the terminal, the content of the ethylene oxide unit being 5% by mass or more and 30% by mass or less, and the mass average molecular weight being 2500 or more and 7500 or less.
Polyether polyol (C): a polymer comprising units of the polyether polyol represented by the general formula (1), mass average molecular weight of 1,000 to 4,000 polyether polyols.
HO— (C ₂ H ₄ O) ₁ —H (1)
(In the formula, l represents any integer of 1 or more.) The toner supply roller according to claim 1 , wherein the polyisocyanate component (D) contains 20% by mass or more of toluene diisocyanate . The toner supply roller according to claim 1 , wherein the conductive agent is carbon black . Toner supply roller according to claim 3, wherein the DBP oil absorption of carbon black is 150 cm ^3/100 g or more 600 cm ^3/100 g or less. DBP oil absorption amount of carbon black, 400 cm ^3/100 g or more 600cm and a ^3/100 g or less, and the toner supply according to claim 4, wherein the BET specific surface area is equal to or less than 1000 m ² / g or more 1400 m ² / g roller. Polyurethane sponge layer, when the respective atmospheric pressure and 125Pa vertical pair of side in the axial direction, airflow rate per unit area of the side surface is 0.8L / cm ² / min or more 3L / cm ² / min or less of any toner supply roller as claimed in claim 1 5, characterized in that the range. The method for producing a toner supply roller according to any one of claims 1 to 6, wherein a polyurethane sponge layer is formed using a mold having a molding cavity having a surface with a contact angle of 85 degrees or more measured using ethylene glycol. And a toner supply roller manufacturing method.

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