JP4509736B2 - Toner supply roller - Google Patents

Description

  The present invention relates to a toner supply roller, and more particularly to an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile, which is formed on a latent image carrier made of an electrophotographic photosensitive member or an electrostatic recording dielectric. A latent image carrier, such as a photoreceptor, which is built in a developing device used to develop and visualize an electrostatic latent image, and is supplied with a predetermined toner (developer) to form an electrostatic latent image. The present invention relates to a toner supply roller used for forming a target toner image on the surface.

  Conventionally, in an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, or a facsimile, an electrostatic latent image formed on an image carrier made of an electrophotographic photosensitive member or an electrostatic recording derivative is developed by a developing device. Visualization as a toner image is performed. In such a developing device, a toner supply roller having a surface layer made of a foamed elastic body such as polyurethane foam for supplying a predetermined toner (developer) accommodated in the hopper to the image carrier side is incorporated. It has been. At this time, it is possible to stabilize toner supply and scraping to the image carrier by opening a cell on the skin surface of the toner supply roller.

  Further, the toner supply roller is desired to have a lower hardness (flexibility) from the viewpoint of toner supplyability, and the polyurethane foam used as the foamed elastic body needs to have a low hardness (soft). Further, the toner supply roller needs to have sufficient recoverability against the compressive force caused by contact with the image carrier.

  A toner supply roller having a surface layer made of such polyurethane foam is manufactured, for example, by the following method. First, a polyol component, an isocyanate component, a foaming agent, a foam stabilizer, and a catalyst are mixed and stirred and injected into a toner supply roller mold. A toner supply roller can be manufactured by foaming this in a mold and then removing the molded product (see Patent Document 1).

  As a method for obtaining a toner supply roller having a surface layer made of polyurethane foam having low hardness and low compression set even under high temperature and high humidity, the total unsaturation is 0.050 meq / g or less and the weight average molecular weight is A polyether polyol of 4500 to 8000 can be used as a polyol component (Patent Document 2). Although the compression set of the toner supply roller is improved by using the low-unsaturated and high-molecular weight polyether polyol described in Patent Document 2, the polyol has a high viscosity, is difficult to foam, and has a low specific gravity toner supply roller. When obtained, the cell opening property on the roller surface required for the toner supply roller was not sufficient.

  Non-Patent Document 1 describes that increasing the number of water used as a foaming agent is effective in reducing the density (reducing hardness) of polyurethane foam and stabilizing the cell opening on the skin surface. In some cases, the aromatic polyurea by-produced by the reaction between the isocyanate component and water deteriorates the compression set of the polyurethane foam. In particular, compression set in a high temperature and high humidity environment such as a temperature of 40 ° C. and a humidity of 95% may be deteriorated.

  Furthermore, polyoxyethylene polyoxypropylene polyol having a hydroxyl equivalent of 800 to 5000, which is obtained by random addition polymerization of 60 to 95 mol% of ethylene oxide as a cell membrane breaker (foam breaker) (see Patent Document 3). The polyol is used in combination with a long-chain polyol, and by containing 0.5 to 10% by mass in the polyol component, the open cell ratio of the polyurethane cold-cure molded product is increased and the crushing operation at the time of molding is facilitated. Alternatively, the crushing work can be eliminated. At the same time, rebound resilience and compression set are improved.

  However, the polyol of the foam breaker is used for the production of large polyurethane foams such as furniture, bedding, vehicles, etc., especially cushioning materials for automobiles, etc., and is a small polyurethane mold such as the toner supply roller of the present invention. It was generally difficult to use for molding. In molding of a small polyurethane foam, the heat generation itself is generally very low, so that the reactivity is lower than that of a large urethane foam. Therefore, if a material such as a foam breaker that inhibits the reaction is added, molding failure tends to occur.

  Patent Document 3 uses a polyoxyethylene polyoxypropylene polyol having a number of functional groups of 2 or more, a molecular weight of 3500 to 10,000, and a terminal oxyethylene added in an amount of 5 to 30 mol% as a long-chain polyol. No investigation has been made to obtain products with good moldability and compression set. For this reason, it may be difficult to obtain a product having a low hardness and a sufficient compression set rate as a toner supply roller.

  Further, as a toner supply roller that effectively improves the aperture ratio, the aperture diameter, and the cell communication state, and has a low hardness and good flexibility, a high PO polyol containing 70% or more of a polypropylene oxide component as a polyol component And a high EO polyol containing 50% or more of a polyethylene oxide component is provided (see Patent Document 4).

  However, the high PO polyol containing 70% or more of the polypropylene oxide component described in Patent Document 4 has a low content of the polyethylene oxide component usually contained as another component. It is known that the reaction between the polyol component and the isocyanate component (urethane formation) is extremely low, and it is not suitable for molding. Furthermore, the combined use of a high PO polyol containing 70% or more of the polypropylene oxide component described in Patent Document 4 and a high EO polyol containing 50% or more of the polyethylene oxide results in an opening ratio, an opening diameter and a cell communication state. Although it is possible to improve, the molecular weight of the polyol component, the EO addition state, and the type of polyisocyanate have not been studied at all, and good moldability, low hardness, good flexibility, and good compression set are obtained. No consideration has been made.

  Further, as the isocyanate component, polyisocyanate mainly composed of toluylene diisocyanate is used from the viewpoint that a soft polyurethane foam having a lower hardness can be easily produced (see Non-Patent Document 2). However, a flexible polyurethane foam produced using a polyisocyanate mainly composed of toluylene diisocyanate has a problem that compression set under a high temperature and high humidity environment is poor. As a method for improving the compression set of the flexible polyurethane foam in a high temperature and high humidity environment, there is a method of increasing the amount of the crosslinking agent used for blending. In such a method, the hardness of the flexible polyurethane foam is also increased. There was a problem of becoming higher.

On the other hand, polyurethane foam using polymethylene polyphenyl polyisocyanate (polymeric MDI) and / or diphenylmethane diisocyanate (monomeric MDI) as the isocyanate component is excellent in compression set in a high temperature and high humidity environment, but is sufficiently low. There was a problem that it was difficult to obtain a flexible urethane foam having hardness.
JP 09-274373 A (page 8-9) JP 2004-037630 A (page 1-13) JP-A-08-245746 (page 1-3) JP 2002-304052 A (page 1-3) Keiji Iwata, "Polyurethane Resin Handbook", Nikkan Kogyo Publishing, September 25, 1987 (first edition), pages 156-159 Yoshio Imai, “Polyurethane Foam”, published by Kobunshi Publishing, May 20, 1987 (first edition), p. 65

  The present invention has been made in the background of such circumstances, and the problem to be solved is that, in a toner supply roller having at least a surface layer formed of a foamed elastic body, the cell opening property is high and sufficient. Another object of the present invention is to provide a toner supply roller having a low hardness and a small compression set even under high temperature and high humidity.

  As a result of intensive studies to achieve the above object, the present inventors have formed a surface layer from a polyurethane foam obtained by using a polyol component containing a specific two components and a specific isocyanate component. Thus, it has been found that it is possible to provide a toner supply roller having excellent cell opening stability on the skin surface, good flexibility at low hardness, and excellent compression set under high temperature and high humidity.

That is, the present invention provides the following (1) to (7).
(1) A toner supply roller having a cored bar and a roller-shaped surface layer formed of a foamed elastic body formed on the outer periphery of the cored bar, wherein the foamed elastic body includes at least the following components: A polyol component (A) containing (B) and component (C) and an isocyanate component (D) containing diphenylmethane diisocyanate or a derivative thereof are obtained by mixing and foaming, and the component (C) A toner supply roller, wherein the content of the component (A) is 5% by mass or more and 50% by mass or less.
Component (B): a copolymer having an ethylene oxide unit at the terminal, the ethylene oxide unit content being 5 mol% or more of the whole, the total unsaturation degree being 0.05 meq / g or less, and the weight average molecular weight being A polyether polyol of more than 4800 and not more than 10,000.
Component (C): a polyether polyol having a weight average molecular weight of 2000 or more and 7000 or less, which is a random copolymer having 60 to 95 mol% of ethylene oxide units.
(2) The polyether polyol contained as the component (B) has a hydroxyl value of 20 to 50 mgKOH / g and an average functional group number of 2.0 to 4.0, as described in (1) above Toner supply roller.
(3) The toner supply roller as described in (1) or (2) above, wherein the total degree of unsaturation of the polyether polyol contained as the component (B) is 0.035 meq / g or less.
(4) The toner supply as described in any one of (1) to (3) above, wherein 3 to 80 parts by mass of diphenylmethane diisocyanate and a derivative thereof are contained in 100 parts by mass of the component (D). roller.
(5) The toner supply roller according to any one of (1) to (4), wherein the component (D) further contains toluylene diisocyanate or a derivative thereof.
(6) The toner supply roller according to any one of (1) to (5), wherein water is mixed as a foaming agent when mixing and foaming.
(7) The density of the foamed elastic body is 0.05 to 0.20 g / cm ³ , the load when the toner supply roller is compressed by 1 mm is 50 to 300 g, and the compression set of the toner supply roller is The toner supply roller according to any one of (1) to (6), wherein the toner supply roller is 20% or less.

  According to the present invention, it is possible to provide a toner supply roller having excellent cell opening stability on the skin surface, low hardness and good flexibility, and excellent compression set under high temperature and high humidity, and the industrial utility value is high.

The present invention is a toner supply roller having a cored bar and a roller-shaped surface layer formed of a foamed elastic body formed on the outer periphery of the cored bar, and the foamed elastic body is at least shown below. A polyol component (A) containing the component (B) and the component (C) and an isocyanate component (D) containing diphenylmethane diisocyanate or a derivative thereof are obtained by mixing and foaming the component (C). The content of the component (A) in the toner is 5% by mass or more and 50% by mass or less.
Component (B): a copolymer having an ethylene oxide unit at the terminal, the ethylene oxide unit content being 5 mol% or more of the whole, the total unsaturation degree being 0.05 meq / g or less, and the weight average molecular weight being A polyether polyol of more than 4800 and not more than 10,000.
Component (C): a polyether polyol having a weight average molecular weight of 2000 or more and 7000 or less, which is a random copolymer having 60 to 95 mol% of ethylene oxide units.

  The present invention will be described below.

(Toner supply roller)
FIG. 1 is a perspective view showing an example of a toner supply roller of the present invention. As shown in FIG. 1, the toner supply roller 1 includes a cylindrical cored bar 2 and a surface layer made of polyurethane foam which is a foamed elastic body provided around the cored bar 2 except for both ends of the cored bar 2. 3 is provided.

  The cored bar 2 can be a conventional cored bar for a toner supply roller, and can be made of a metal such as iron. The outer diameter of the cored bar is preferably 2 to 10 mm.

  The surface layer 3 made of polyurethane foam has a plurality of cell openings communicating with the inside thereof on the surface. The thickness of the surface layer is preferably 1 to 20 mm, and more preferably 2 to 10 mm. When the thickness is within these ranges, the toner supply roller has better toner transportability.

  The toner supply roller of the present invention may have an adhesive layer, an elastic layer, etc., which will be described later, between the core metal and the surface layer as necessary.

(Polyurethane foam)
In the present invention, the density of the polyurethane foam used in the toner supply roller is preferably 0.05~0.20g / cm ^3, more preferably 0.07~0.15g / cm ^3. Further, the load when the toner supply roller is compressed by 1 mm is preferably 50 to 300 g, more preferably 100 to 250 g. When in this range, the toner supply property of the toner supply roller is good. Further, the compression set of the toner supply roller is preferably 20% or less. In addition, about each physical property, it measured according to the method as described in an Example.

  Hereinafter, materials used as raw materials for polyurethane foam in the present invention will be described.

  The polyurethane foam to be the surface layer of the toner supply roller of the present invention comprises a polyol component [component (A)], an isocyanate component [component (D)], and optionally used catalysts, foaming agents, foam stabilizers, and other auxiliaries. Is obtained by mixing and foaming.

<Component (A): Polyol component>
In this invention, the polyol component containing the component (B) mentioned later and a component (C) is used as a component (A). You may further contain the well-known compound which can be used as a polyol component for forming a polyurethane foam. It is preferable that 85-100 mass% is contained in a component (A) in the sum total of a component (B) and a component (C).

<Component (B): Polyether polyol>
In the present invention, the component (B) is a copolymer having an ethylene oxide unit at the terminal, the content of the ethylene oxide unit is 5 mol% or more of the whole, and the total unsaturation is 0.05 meq / g or less. A polyether polyol having a weight average molecular weight of more than 4800 and 10,000 or less is used. The polyether polyol as the component (B) may be one kind or a combination of two or more kinds.

  The polyether polyol used as the component (B) is an ethylene oxide-propylene oxide copolymer having an ethylene oxide unit at the terminal, and the content of the ethylene oxide unit is 5 mol% or more. A preferable content of ethylene oxide units is 5 to 50 mol%. By having an ethylene oxide unit at the terminal, the reactivity for forming a urethane foam can be secured, and molding can be performed. Further, by using the polyether polyol having the ethylene oxide unit content as described above as the component (C), a toner supply roller having more excellent cell opening stability can be obtained.

  The above polyether polyol is obtained by addition polymerization of propylene oxide and ethylene oxide to an initiator such as glycerin, trimethylolpropane, ethylene glycol, propylene glycol, pentaerythritol, sorbitol, and block addition of ethylene oxide at the chain end. It is. The amount of ethylene oxide to be added can be appropriately set in consideration of the ethylene oxide content, weight average molecular weight and the like of the target copolymer.

  Here, the total unsaturation degree of the polyether polyol used as the component (B) needs to be 0.050 meq / g or less. Preferably, it is 0.035 meq / g or less. When it is larger than 0.050 meq / g, the compression set rate tends to deteriorate. The total degree of unsaturation is measured by the method described in JIS K-1557.

  In general, a polyether polyol contains a monool component of several percent to several tens of percent. The content of the monool component indicates that the content of the monool component is lower as the total unsaturation value is smaller. A polyether polyol having a small total unsaturation is likely to have a uniform network structure when reacted with a polyisocyanate to form a polyurethane foam. Therefore, it is considered that compression set under high temperature and high humidity is improved. Moreover, when such a polyether polyol with a small monool component is used, the addition ratio of isocyanate (isocyanate index = number of NCO groups / number of active hydrogen groups × 100) can be reduced. The reason for this is that in polyether polyols with a small monool component, there is little reaction between the monool component and the isocyanate that becomes non-uniform in the network structure, so that the isocyanate index can be reduced. By reducing the isocyanate index, the hardness can be further reduced. However, if the isocyanate index is less than 60, resinification becomes insufficient, and the moldability of the toner supply roller becomes extremely bad. Conversely, if the isocyanate index is greater than 120, there is a problem that the hardness is increased.

  Furthermore, the weight average molecular weight of the polyether polyol used as the component (B) needs to exceed 4800 and not more than 10,000. When the weight average molecular weight is greater than 10,000, the viscosity increases, and handling, casting, and uniform mixing with isocyanate become difficult. When the weight average molecular weight is less than 4800, the hardness increases. More preferably, it is 5000-85000.

  The polyether polyol used as component (B) preferably has a hydroxyl value of 20 to 50 mgKOH / g and an average functional group number of 2.0 to 4.0. When the hydroxyl value is less than 20 mgKOH / g or less than the average functional group number of 2.0, the toner supply roller tends to have poor compression set under high temperature and high humidity, and the hydroxyl value is more than 50 mgKOH / g. If the average functional group number is greater than 4.0, the hardness of the toner supply roller tends to increase. The hydroxyl value is more preferably 20 to 40 mgKOH / g. The hydroxyl value is measured by the method described in JIS K-1557.

<Component (C): Polyether polyol>
In the present invention, a polyether polyol having a weight average molecular weight of 2000 or more and 7000 or less, which is a random copolymer having 60 to 95 mol% of ethylene oxide units, is used as the component (C). The polyether polyol as the component (C) may be one kind or a combination of two or more kinds.

  The polyether polyol used as the component (C) is an ethylene oxide-propylene oxide random copolymer having 60 to 95 mol% of ethylene oxide units. A preferable content of the ethylene oxide unit is 60 to 80 mol%. By using a polyether polyol, which is a random copolymer having an ethylene oxide unit content in the above range, as the component (C), a toner supply roller having more excellent cell opening stability can be obtained.

  The polyether polyol can be obtained by random copolymerization using a combination of ethylene oxide and propylene oxide monomers. The polymerization method can be appropriately set in consideration of the polymerizability of ethylene oxide and propylene oxide, the target weight average molecular weight, and the like.

  Here, the weight average molecular weight of the polyether polyol used as the component (C) needs to be 2000 to 7000. That is, when the weight average molecular weight is within this range, the hardness suitable for use as a toner supply roller can be obtained.

  Since component (C) contains a large number of ethylene oxide units, it is excellent in compatibility (dispersibility) with water. Further, since the component (C) has a cell bubble-breaking effect, not only the cells inside the toner supply roller can be made into continuous cells but also the cells on the skin surface can be opened. In other words, in order to open cells on the skin surface, it is not necessary to increase the foaming pressure in the mold by increasing the content of water as a foaming agent, so it is possible to reduce the by-produced aromatic polyurea Become. Furthermore, the composition as a raw material can be easily mixed, and a compact molding like the toner supply roller of the present invention becomes possible.

  The component (C) needs to be contained in the component (A) in an amount of 5 to 50% by mass. It is preferably more than 10% by mass and 50% by mass or less. By being in this range, a toner supply roller having more excellent cell opening stability can be obtained.

<Component (D): Isocyanate component>
In the present invention, an isocyanate component containing diphenylmethane diisocyanate (MDI) or a derivative thereof is used as component (D). By using such a component (D) as an isocyanate component, a toner supply roller having a low hardness and good compression set in a high temperature and high humidity environment can be obtained.

  As a derivative of diphenylmethane diisocyanate, for example, modified MDI, polymeric MDI, or the like can be used. One kind of diphenylmethane diisocyanate or a derivative thereof may be used, or two or more kinds thereof may be used in combination. You may use the thing prepolymerized with the polyol.

  Moreover, you may contain the well-known compound which can be used as an isocyanate component for forming a polyurethane foam. For example, aliphatic polyisocyanates and derivatives thereof such as toluylene diisocyanate, polymethylene polyphenyl polyisocyanate and hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate, and derivatives thereof may be contained. You may use the thing prepolymerized with the polyol. These may be used alone or in combination of two or more. It is preferable to contain toluylene diisocyanate or a derivative thereof.

  The total amount of diphenylmethane diisocyanate or a derivative thereof contained in 100 parts by mass of component (D) is preferably 3 to 80 parts by mass.

<catalyst>
In the present invention, a catalyst can be used as necessary. There is no restriction | limiting in particular in the kind of catalyst, You may use a conventionally well-known thing. For example, amine-based catalysts (triethylenediamine, bis (dimethylaminoethyl) ether, N, N, N ′, N′-tetramethylhexanediamine, 1,8-diazabicyclo (5,4,0) undecene-7, 1, 5-diazabicyclo (4,3,0) nonene-5, 1,2-dimethylimidazole, N-ethylmorpholine, N-methylmorpholine, etc.), organometallic catalysts (tin octylate, tin oleate, dibutyltin dilaurate, Dibutyltin diacetate, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetrakis (2-ethylhexyloxy) titanium, etc.), acid salt catalysts with reduced initial activity of the amine-based catalyst and organometallic catalyst ( Carboxylate, formate, octylic acid, borate, etc.) are used. One kind of this catalyst may be used, or two or more kinds may be used in combination.

<Foaming agent>
In the present invention, a foaming agent can be used as necessary. In particular, water is suitably used as a blowing agent because it reacts with polyisocyanate to generate carbon dioxide. In addition, chlorofluorocarbons (HFC-134A, etc.), hydrocarbons (cyclopentane, etc.) developed for the purpose of protecting the global environment, other blowing agents, and these in combination with water The gist of the invention is not impaired.

<Foam stabilizer>
In the present invention, a foam stabilizer can be used as necessary. Examples of the foam stabilizer include water-soluble polyether siloxane from polydimethylsiloxane and ethylene oxide (EO) / propylene oxide (PO) copolymer, sodium salt of sulfonated ricinoleic acid, and polysiloxane / polyoxyalkylene copolymer. And the like. Among these foam stabilizers, water-soluble polyether siloxane from polydimethylsiloxane and EO / PO copolymer is preferred.

<Other auxiliaries>
In the present invention, as the auxiliary agent, 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. Addition of these other auxiliaries as necessary does not impair the gist of the present invention.

(Method for forming surface layer)
In the present invention, the method for producing the polyurethane foam is not particularly limited and may be a conventional method. An example is as follows. First, the polyol component which is the component (A), the polyisocyanate component which is the component (D), and a catalyst, a foaming agent, a foam stabilizer and other auxiliaries used as required are homogeneously mixed and then reaction-cured. By doing so, a polyurethane foam is obtained.

  Although there is no restriction | limiting in particular about the temperature and time at the time of mixing each raw material, Mixing temperature is 10-90 degreeC normally, Preferably it is the range of 20-60 degreeC, and mixing time is 1 second-10 minutes normally. Preferably, it is about 3 seconds to 5 minutes.

  Further, when the reaction is cured, a polyurethane foam can be produced by foaming by a conventionally known method. There is no restriction | limiting in particular about the foaming method here, Any methods, such as the method of using a foaming agent and the method of mixing bubbles by mechanical stirring, can be used. The expansion ratio may be determined as appropriate and is not particularly limited.

  The method for joining the core metal and the polyurethane foam as the surface layer is not particularly limited, and a method in which the metal core is previously disposed in the mold (molding die) and the above raw material mixture is cast and cured, or the raw material For example, a method in which the mixture is preliminarily formed into a predetermined shape to be a surface layer and then bonded to the core metal can be used. In either method, an adhesive layer can be provided between the cored bar and the polyurethane foam as necessary, and a known material such as an adhesive or a hot melt sheet can be used as the adhesive layer. The method for forming the surface layer portion made of polyurethane foam is not particularly limited, and in addition to a known method, for example, a method of casting into a mold having a predetermined shape as described above, the polyurethane foam in a block state is predetermined by cutting. For example, a method of cutting to a predetermined size, a method of obtaining a predetermined size by polishing, or a method of appropriately combining these methods can be used.

  In particular, a method in which a core metal is previously disposed in a mold (molding die) and the above raw material mixture is cast-cured is preferable. More specifically, first, a rod-shaped metal core is placed in a predetermined mold for toner supply roller. As the mold, a pipe-shaped mold or a split mold can be used, but a pipe-shaped mold is more preferable. Then, a toner supply roller can be obtained by injecting the raw material mixture into the mold, causing a foaming reaction, and taking out the obtained molded product from the mold.

  According to the present invention as described above, it is possible to manufacture a toner supply roller that has excellent cell opening stability on the skin surface, low hardness, good flexibility, and excellent compression set in a high temperature and high humidity environment. It becomes.

  Examples of the present invention and comparative examples will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Needless to say. In addition to the following examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements can be made.

  The analytical values of polyether polyol [component (B); obtained by adding propylene oxide to glycerin and ethylene oxide at the chain end in a block form], which is one of the urethane foam raw materials used in Examples and Comparative Examples, are shown. Tables 2 and 3 show the composition of the urethane foam raw materials used in the surface layer formation of the toner supply rollers of Examples and Comparative Examples and the properties of the obtained toner supply rollers. In addition, all the components (B) described in Table 1 have an ethylene oxide unit at the terminal. Table 2 shows the weight average molecular weight, total degree of unsaturation, and isocyanate index of the component (B) used.

  Further, the toner supply rollers of each of the examples and the comparative examples were manufactured as follows. Each component shown in Table 2 was mixed by mechanical stirring, and this mixture was poured into a pipe-shaped mold having an inner diameter of 16 mm into which a metal shaft having a diameter of 5 mm and a length of 290 mm was inserted, and placed in an oven at 60 ° C. for 30 minutes. The foam was cured by heating. Thereafter, the toner was removed to produce a toner supply roller.

  Further, the measured values of the physical properties of the toner supply roller and the component (B) prepared in Examples and Comparative Examples were measured by the following methods.

<Hydroxyl value>
It was measured by the method described in JIS K-1557.

<Total unsaturation>
It was measured by the method described in JIS K-1557.

<Load at 1 mm compression (hardness)>
As shown in FIGS. 2A and 2B, the toner supply roller 1 is supported by the cored bar 2 at both ends, and the surface layer 3 made of polyurethane foam is 50 mm long (in the longitudinal direction of the roller). X Expressed as a load (g) at 1 mm displacement (compression) when pressed at a speed of 10 mm / min with a jig 4 having a plate-like pressing surface with a width of 10 mm (thickness: 10 mm). is there. The larger the value is, the harder the surface layer 3 made of polyurethane foam is. Further, as shown in the figure, measurement points were measured at three locations in the axial direction, four locations every 90 degrees in the circumferential direction in each axial direction, for a total of 12 locations.

<Compression set>
As shown in FIGS. 3A and 3B, the toner supply roller 1 is supported by the cored bar 2 at both ends, and a sleeve 5 having a diameter of 16 mm is brought into contact with the surface layer 3 made of polyurethane foam. It shows the degree of restoration after 30 minutes after being taken out and released for 30 hours at a temperature of 40 ° C. and a humidity of 95% in a compressed state of 5 mm, and was calculated according to the following formula.

Compression set Cs (%) = (t ₀ −t ₁ ) /1.5×100
t ₀ : Radius before the test of the place compressed 1.5 mm t ₁ : Radius of the place compressed 1.5 mm after 30 minutes of compression release Note that the measurement point is an average of three points measured in the axial direction of the compressed part The value was determined.

<density>
The volume of the urethane foam of the toner supply roller was calculated, and the density was determined by measuring the mass of the urethane foam of the toner supply roller.

<Cell opening ratio>
An enlarged image of the roller surface was measured by image analysis.

    Cell opening ratio = cell opening area / measurement area

※配合量＝質量部
１）三井武田ケミカル（株）製ポリエーテルポリオールの商品名。重量平均分子量３０００、エチレンオキシドユニットを７０〜８０モル％有するエチレンオキシド−プロピレンオキシドランダム共重合体。（ＯＨ価＝５０ｍｇＫＯＨ／ｇ）
２）キシダ化学（株）製架橋剤の商品名
３）東レ・ダウコーニング（株）製シリコーン整泡剤の商品名
４）東ソー（株）製第三級アミン触媒の商品名
５）三共エアプロダクツ（株）製第三級アミン触媒の商品名
６）三井武田ケミカル（株）製ポリイソシアネート混和物の商品名。（モノメリックおよびポリメリックＭＤＩ混合物５０質量％、ＴＤＩ５０質量％の混合物）。（ＮＣＯ％＝４０）
７）ＮＣＯ基数／活性水素基数×１００
８）セル開口率が５０％以上：○、セル開口率が２０〜５０％：△、セル開口率が２０％未満：×。
９）１ｍｍ圧縮時の荷重が５０〜３５０ｇ、且つ、セル開口性○、且つ、圧縮永久歪率２０％以下：○、それ以外：×
実施例１〜４では、密度０．１２〜０．１４ｇ／ｃｍ³、１ｍｍ圧縮時の荷重１５４〜２５５ｇ、圧縮永久歪率９．７〜１５．２％と良好であり、セル開口性も良好であった。これに対し比較例１、２及び４では、ほぼ同等の密度、１ｍｍ圧縮時の荷重において圧縮永久歪率２５．２〜３５．３％と高く、比較例３では、ほぼ同等の密度で、圧縮永久歪率２０％以下であったが、１ｍｍ圧縮時の荷重は３５５ｇと高かった。さらに、比較例１及び２においては、セル開口性が低下した。

* Blending amount = part by mass 1) Trade name of polyether polyol manufactured by Mitsui Takeda Chemical Co., Ltd. An ethylene oxide-propylene oxide random copolymer having a weight average molecular weight of 3000 and an ethylene oxide unit of 70 to 80 mol%. (OH value = 50 mgKOH / g)
2) Product name of cross-linking agent manufactured by Kishida Chemical Co., Ltd. 3) Product name of silicone foam stabilizer manufactured by Toray Dow Corning Co., Ltd. 4) Product name of tertiary amine catalyst manufactured by Tosoh Corp. 5) Sankyo Air Products Trade name of Tertiary amine catalyst manufactured by Co., Ltd. 6) Trade name of polyisocyanate admixture manufactured by Mitsui Takeda Chemical Co., Ltd. (Monomeric and polymeric MDI mixture 50 wt%, TDI 50 wt% mixture). (NCO% = 40)
7) Number of NCO groups / number of active hydrogen groups × 100
8) Cell opening ratio is 50% or more: ◯, Cell opening ratio is 20-50%: Δ, Cell opening ratio is less than 20%: ×.
9) The load at the time of 1 mm compression is 50 to 350 g, the cell opening property ◯, and the compression set 20% or less: ◯, otherwise: ×
In Examples 1 to 4, the density is 0.12 to 0.14 g / cm ³ , the load at the time of 1 mm compression is 154 to 255 g, the compression set is 9.7 to 15.2%, and the cell opening is also good. Met. On the other hand, in Comparative Examples 1, 2 and 4, the compression set rate is as high as 25.2 to 35.3% at a load of 1 mm when compressed, and in Comparative Example 3, compression is performed at a substantially equivalent density. Although the permanent set was 20% or less, the load at the time of 1 mm compression was as high as 355 g. Furthermore, in Comparative Examples 1 and 2, the cell opening property was lowered.

  From this result, it can be seen that the toner supply roller shown in this example has low hardness and excellent compression set.

FIG. 3 is a perspective view illustrating a schematic configuration of a toner supply roller of the present invention. 4A and 4B are explanatory views showing a method for measuring the hardness of a surface layer made of polyurethane foam of a toner supply roller, wherein FIG. 5A is a diagram viewed from a direction perpendicular to the axial direction of the toner supply roller, and FIG. It is the figure seen from the direction parallel to an axial direction. 4A and 4B are explanatory views showing a method for measuring a compression set rate of a surface layer made of polyurethane foam of a toner supply roller, wherein FIG. 5A is a view seen from a direction perpendicular to the axial direction of the toner supply roller, and FIG. It is the figure seen from the direction parallel to the axial direction of a supply roller.

Explanation of symbols

1 Toner supply roller 2 Core 3 Surface layer 4 Jig 5 Sleeve

Claims (7)

A toner supply roller having a cored bar and a roller-shaped surface layer formed of a foamed elastic body formed on the outer periphery of the cored bar,
The foamed elastic body is obtained by mixing and foaming at least a polyol component (A) containing the following components (B) and (C) and an isocyanate component (D) containing diphenylmethane diisocyanate or a derivative thereof. A toner supply roller obtained, wherein the content of the component (C) in the component (A) is 5% by mass or more and 50% by mass or less.
Component (B): a copolymer having an ethylene oxide unit at the terminal, the content of the ethylene oxide unit being 5 mol% or more of the whole, the total unsaturation being 0.050 meq / g or less, and the weight average molecular weight being A polyether polyol of more than 4800 and not more than 10,000.
Component (C): a polyether polyol having a weight average molecular weight of 2000 or more and 7000 or less, which is a random copolymer having 60 to 95 mol% of ethylene oxide units.   2. The toner supply roller according to claim 1, wherein the polyether polyol contained as the component (B) has a hydroxyl value of 20 to 50 mg KOH / g and an average functional group number of 2.0 to 4.0.   The toner supply roller according to claim 1, wherein the polyether polyol contained as the component (B) has a total unsaturation of 0.035 meq / g or less.   The toner supply according to any one of claims 1 to 3, wherein the total amount of diphenylmethane diisocyanate or a derivative thereof contained in 100 parts by mass of the component (D) is 3 to 80 parts by mass. roller.   The toner supply roller according to claim 1, wherein the component (D) further contains toluylene diisocyanate or a derivative thereof.   The toner supply roller according to claim 1, wherein water is mixed as a foaming agent when the mixed foaming is performed. The density of the foamed elastic body is 0.05 to 0.20 g / cm ³ , the load when the toner supply roller is compressed by 1 mm is 50 to 300 g, and the compression set of the toner supply roller is 20% or less. The toner supply roller according to claim 1, wherein the toner supply roller is provided.

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