JP3480685B2 - Conductive member and image forming apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive member and an image forming apparatus used in an electrophotographic process. More specifically, it has excellent ozone resistance, heat resistance and moist heat resistance. The present invention relates to a conductive member that does not contaminate an image forming body such as a photoreceptor due to surface melting or hydrolysis to cause an image defect, and an image forming apparatus equipped with the conductive member.

[0002]

2. Description of the Related Art In recent years, with the progress of electrophotographic technology, medium resistance elastic rollers have been attracting attention as a transfer member, a toner supplying member, a charging member, etc. of a dry electrophotographic apparatus, and a transfer roller, a developing roller, a charging roller. It is used for etc. And, for this medium resistance elastic roller, a polymer elastomer or polymer foam having rubber elasticity has been used as a material. Conventionally, members used for such purposes include, for example, carbon black, metal oxides,
NBR and E with conductivity imparted by ionic compounds, etc.
There are elastomers and foams such as PDM, silicone rubber and polyurethane. With the polyurethane material, a low hardness member suitable for the above-mentioned conductive member can be obtained, and a foam having fine and uniform cells can be obtained by a method using a foam such as water or a low boiling point compound or a method by mechanical stirring. It can be used for the above members. However, in the case of a polyurethane material, the ozone resistance is poor, the surface of the member is decomposed and melted by ozone, and the image forming apparatus such as the photoconductor used in contact is likely to be contaminated, and the image defect due to the contamination of the image forming body is likely to occur. That has the disadvantage.

[0003] Normally, ozone is generated in the vicinity of a member using a high voltage inside the electrophotographic apparatus, and its concentration is 6 ppm.
To the extent. On the other hand, the electrophotographic apparatus requires a mechanical life of printing about 90,000 sheets, and assuming a printing speed of 10 sheets per minute, a life of 150 hours is required. That is,
The medium resistance elastic member used for the above-mentioned applications is required not to melt even when exposed to high concentration ozone. As a method of preventing ozone deterioration of polyurethane, there is a method of adding various organic deterioration inhibitors to polyurethane, but most of the organic deterioration inhibitors themselves contaminate image forming bodies such as photoconductors. As a matter of fact, the deterioration preventing agent which is effective for ozone deterioration and does not contaminate the image formation has not been found yet. A method of adding inorganic powder to polyurethane as an anti-degradation agent is conceivable. However, although there are few cases where the inorganic material itself contaminates the image forming body, no one effective for ozone deterioration has been found so far.

On the other hand, the medium resistance elastic member used for the above-mentioned applications may be stored or used in an environment of high temperature or high temperature and high humidity, and the member melts even in the environment of high temperature or high temperature and high humidity. Alternatively, it is required not to hydrolyze. When a member is melted or hydrolyzed in a high temperature environment, high temperature and high humidity environment, etc., like the melting of the member by ozone,
It is known that a melt or a decomposed product contaminates an image forming body to cause an image defect, and also causes an image defect due to a dimensional change or hardness change due to deformation. Regarding heat resistance, it is required that the member does not melt in a heat resistance test at a temperature of 90 ° C. for 72 hours. On the other hand, regarding moisture resistance,
It is required that the member does not melt or hydrolyze in a humidity and heat resistance test at a temperature of 105 ° C. and a relative humidity of 100% for 3 hours. Whether or not the surface of the member has melted can be determined by the following method. After the roller-shaped member after each durability test was left in an atmosphere of a temperature of 20 ° C. and a relative humidity of 50% for 24 hours, an aluminum flat plate having a diameter of 12 mm was pressed against the roller-shaped member with a force of 50 gf, and then the flat plate was 10 mm / min. It is determined that the roller surface is melted when the maximum value of the tensile force when separated at a speed exceeds 1 gf, and it is determined that the roller surface is not melted when the maximum value is 1 gf or less. A digital force gauge with a minimum reading of 0.1 gf equipped with an aluminum flat plate can be used to determine whether or not it has melted.

When the member is hydrolyzed without melting, it may not be possible to determine the presence or absence of the decomposition with the above digital force gauge, but it is possible to determine the presence or absence of the decomposition by measuring the amount of extracted acetone. it can. That is, when an acetone extraction test was performed using a Soxhlet extractor under the conditions of a sample of about 5 g, acetone of about 150 ml, a bath temperature of 80 ° C. and an extraction time of 8 hours, the acetone extraction amount was about 10 before the wet heat resistance test. Although it is less than wt%, the amount of extracted acetone is 1 by hydrolysis after the test.
It may increase to 5% by weight or more.

[0006]

Under the circumstances, the present invention has excellent ozone resistance, heat resistance and wet heat resistance, and the surface is melted or hydrolyzed to give a photoreceptor or the like. It is an object of the present invention to provide a conductive member that does not contaminate the image forming body and cause an image defect, and an image forming apparatus equipped with the conductive member.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a conductive member having excellent heat resistance and moist heat resistance as well as ozone resistance, and as a result, magnesium oxide in a specific ratio It was found that the polyurethane material contained in 1. is excellent in ozone resistance, and that the polyol obtained by appropriately selecting the polyol component and the polyisocyanate component is excellent in ozone resistance, heat resistance and moist heat resistance. The present invention has been completed based on such findings. That is, the present invention relates to a roller-shaped conductive member using a polyurethane material, wherein the polyurethane material mainly contains a polyol component and at least one selected from saturated aliphatic polyisocyanates and isocyanurate modified products thereof. A polyurethane material produced from a polyisocyanate component which is mixed with an ionic conductive agent which is a quaternary ammonium salt of carboxylic acid or alkylsulfuric acid, and left for 150 hours in an environment having an ozone concentration of 6 ppm and a temperature of 35 ° C. After that, a member with a diameter of 12 is left for 24 hours in an atmosphere of a temperature of 20 ° C and a relative humidity of 50%.
After pressing an aluminum flat plate of 50 mm with a force of 50 gf for 20 seconds, and then pulling the flat plate at a speed of 10 mm / min, the maximum tensile force is 1 gf or less. It is provided. The present invention also provides an image forming apparatus having the above-mentioned conductive member mounted thereon.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive member of the present invention is a roll-shaped member made of a polyurethane material, and is left for 150 hours in an environment of ozone concentration of 6 ppm and temperature of 35 ° C. 50mm of aluminum flat plate with a diameter of 12mm is put on the member left for 24 hours in the atmosphere of 50% humidity
After pressing with gf force for 20 seconds, flat plate 10mm /
The maximum value of the tensile force when separated at a speed of minute is 1 gf or less, which is excellent in ozone resistance. In addition, the pulling force is the minimum reading of 0.1g with an aluminum plate attached.
It is a value measured using a digital force gauge of f. To obtain such a polyurethane material having excellent Ozo resistance, for example, (1) a method of incorporating 0.1 to 10% by weight of magnesium oxide in the polyurethane material based on the total weight of the material, or (2) As will be described later, a method of appropriately selecting a polyol component and a polyisocyanate component, which are main components of the polyurethane material, or a method of combining these can be preferably used. In the above method (1) of containing magnesium oxide, when the content of magnesium oxide is less than 0.1% by weight, ozone resistance is not sufficiently imparted and the surface of the member is easily melted by ozone, so that 10% by weight is added. If it exceeds the above range, mechanical properties such as elongation and tensile strength may be deteriorated, and compression set may be deteriorated. The optimum content of magnesium oxide varies depending on the situation, but is usually in the range of 1 to 5% by weight in consideration of ozone resistance and mechanical properties.

Next, the polyol component and polyisocyanate component, which are the main components of the polyurethane material of (2) above, will be described. Examples of the polyol component include polyether polyol, polyester polyol, and hydrophobic polyol. Preferred examples of the polyether polyol include polyols obtained by adding ethylene oxide or propylene oxide to polyhydric alcohol such as glycerin, polytetramethylene glycol, polyethylene glycol, polypropylene glycol and polybutanediol. Examples of the polyester polyol include condensed polyester polyols obtained by condensation of dicarboxylic acids with diols and triols, lactone type polyester polyols obtained by ring-opening polymerization of lactones in the presence of diols and triols, and end of polyether polyols. Preference is given to ester-modified polyols obtained by ester-modified with lactone. Further, as the hydrophobic polyol, for example, polyisoprene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol and the like are preferably mentioned.

These polyol components may be used alone or in combination of two or more kinds. Among them, polyether polyol is particularly preferable from the viewpoint of obtaining a conductive member having excellent wet heat resistance. Is. In addition, since the polyester polyol has a slightly inferior wet and heat resistance, it can be used by mixing it with a polyether polyol or by adding an isocyanate in the form of a carbodiimide-modified product that has an effect of preventing the hydrolysis of ester bonds. You can also let it. On the other hand, as the polyisocyanate component, at least one selected from (a) aromatic polyisocyanate, or (b) saturated aliphatic polyisocyanate, saturated alicyclic polyisocyanate and their isocyanurate modified products is preferably used. To be

Examples of the aromatic polyisocyanate as the component (a) include tolylene diisocyanate (TD).
I), diphenylmethane diisocyanate (MDI),
Crude diphenylmethane diisocyanate (Crude MD
I) and the like. These may be used alone,
You may use it in combination of 2 or more type. By using this aromatic polyisocyanate as the polyisocyanate component, polyurethane having good heat resistance can be obtained. However, since this polyurethane is inferior in ozone resistance, in this case, it is preferable that the above-mentioned magnesium oxide is contained in the polyurethane material to impart desired ozone resistance. That is, a polyurethane material obtained by using the polyether polyol as a polyol component and the aromatic polyisocyanate as a polyisocyanate component, and containing magnesium oxide in the above proportion has good ozone resistance, heat resistance and wet heat resistance. It will be

Examples of the polyisocyanate as the component (b) include saturated aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, saturated alicyclic polyisocyanates and their isocyanates. Examples thereof include modified products (modified polyisocyanates) of nurate, carbodiimide, buret, urethane and the like. Using one or more of these polyisocyanates, the polyurethane obtained by curing the polyether polyol itself has good ozone resistance, and even if it does not contain the magnesium oxide, ozone is obtained at room temperature. Concentration 6
Even when exposed to ppm for 150 hours, the surface of the member does not melt, and it is suitable as a material for a conductive member used for applications such as electrophotographic devices. Of course, magnesium oxide may be contained if desired. When a saturated aliphatic polyisocyanate or a saturated alicyclic polyisocyanate such as hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate is used among these polyisocyanates, the resulting polyurethane has slightly heat resistance. Inferiority, there is a risk of melting when left for 72 hours at 90 ℃,
Depending on the usage conditions of the conductive member, it may cause problems.

To improve the heat resistance of polyurethane,
It suffices to introduce an isocyanurate bond having excellent heat resistance. Therefore, heat resistance can be improved by using the above-mentioned saturated isocyanurate modified product of saturated aliphatic polyisocyanate or saturated alicyclic polyisocyanate. That is, by using the polyether polyol as the polyol component, by using the isocyanurate modified product of the saturated aliphatic polyisocyanate or saturated alicyclic polyisocyanate as the polyisocyanate component, ozone resistance, heat resistance and moist heat resistance A good polyurethane is obtained. In the present invention, a polyurethane material that does not substantially melt when left at 90 ° C. for 72 hours, or substantially melts or hydrolyzes even when left for 3 hours in an environment at a temperature of 105 ° C. and relative humidity of 100%. Those that do not undergo deformation and are not deformed are preferable. Therefore, in order to obtain a polyurethane material having such properties, it is preferable to appropriately select and use the polyisocyanate component and the polyol component.

In the conductive member of the present invention, a conductive polymer material obtained by mixing the polyurethane material with a conductivity-imparting agent is used. The conductivity-imparting agent is not particularly limited, and an electron-conducting agent such as carbon black, metal oxide powder, and metal powder, and various ion-conducting agents can be used, but in order to reduce the variation in the electric resistance position. In addition, it is desirable to use an ion conductive agent as the conductivity imparting agent. There is no particular limitation on the kind of the ion conductive agent, and examples thereof include dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium and lauryltrimethylammonium, octadecyltrimethylammonium such as stearyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified aliphatic. Perchlorates such as dimethylethylammonium, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, alkylsulfates, carboxylates, sulfonates and other ammonium salts; Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, trifluores of alkali metals or alkaline earth metals such as lithium, sodium, calcium and magnesium. Methyl sulfate, and sulfonic acid salts. Among these, quaternary ammonium salts are preferable, and quaternary ammonium salts of carboxylic acid and alkylsulfuric acid are particularly preferable because the resistance increase during continuous energization is small. This ionic conductive agent may be used alone or in combination of two or more. Further, the blending amount thereof is not particularly limited and may be appropriately selected according to various situations, but normally, with respect to 100 parts by weight of the polyurethane material,
The amount is 0.001 to 5 parts by weight, preferably 0.05 to 2 parts by weight.

Next, the method for producing the conductive polymer material used in the present invention is not particularly limited, and a conventional method may be used. An example thereof is as follows. First, the polyisocyanate component, the polyol component,
Ion conductive agent and optionally used chain extender, other conductivity imparting agent, catalyst, antiaging agent, reinforcing agent, colorant, foam stabilizer, etc. are homogeneously mixed, and then heated to react and cure. A conductive polymer material containing a conductivity-imparting agent in a polyurethane elastomer can be obtained. Further, the polyol component is pre-isocyanated with the polyisocyanate component, and the ionic conductive agent and optionally a chain extender, other conductivity-imparting agent, catalyst, antiaging agent, reinforcing agent, coloring agent, conditioning agent After the foaming agent and the like are homogeneously mixed, they may be heated to react and cure. Also,
A foam body is also preferable, and when the foam body is heated and reacted and cured, a conductive material containing a conductivity-imparting agent in the polyurethane foam is obtained by foaming by a conventionally known method. To be The foaming method is not particularly limited, and any method such as a method using a foaming agent and a method of mixing bubbles by mechanical stirring can be used. The expansion ratio may be set appropriately,
There is no particular limitation. The polyurethane foam or polyurethane elastomer may be crosslinked, if desired, for the purpose of improving heat resistance, chemical resistance, mechanical strength and the like.

The method for producing the roller-shaped conductive member of the present invention is not particularly limited, and various known methods may be used. For example, by coating a core metal such as iron plated with nickel or stainless steel with the conductive polymer material, and further coating the outside with a conductive, semiconductive, or insulating coating depending on the application, 1 x 10 ⁵ to 1 x 10 ¹⁰
The roller-shaped conductive member of the present invention showing a stable resistance value in the medium resistance region of Ω can be obtained. In the conductive member of the present invention thus obtained, when the ion conductivity agent is used as the conductivity-imparting agent, the variation in the electric resistance at 24 places is
For example, the logarithm of the resistance value is less than 0.5, which is extremely small, which is preferable. The position variation of this electric resistance is as follows: temperature 20 ° C, humidity 50%, applied voltage 100
At 0 V, both ends of the roller-shaped elastic member are set to 500
Using a copper plate with a width of 1 cm and pressure contact with gf force, the electrical resistance between the cored bar and the copper plate is 6 places at equal intervals in the longitudinal direction of the elastic member, and 4 places in every 90 degrees in 4 directions in the circumferential direction. Is measured and expressed as the difference in logarithmic value of the resistance between the highest resistance part and the lowest resistance part.

Further, this conductive member is, as described above,
After being left for 150 hours in an environment with an ozone concentration of 6 ppm and a temperature of 35 ° C., an aluminum flat plate having a diameter of 12 mm was pressed with a force of 50 gf for 20 seconds on a member left for 24 hours in an atmosphere of a temperature of 20 ° C. and a relative humidity of 50%. The maximum value of the tensile force when the flat plate is pulled apart at a speed of 10 mm / min is 1 gf or less, which is excellent in ozone resistance. Furthermore, the conductive member of the present invention has an Asker C hardness of 10-6.
Those in the range of 0 degrees are preferable. The Asker C hardness is based on the Japan Rubber Association standard SRIS 0101
It is a value measured by the test method of the spring hardness test described in <Physical test method for expanded rubber>. However, the test sample used a roller. The conductive member of the present invention is
The use thereof is not particularly limited, but it is used as, for example, a charging member, a developing member, a transferring member, a toner supplying member, a cleaning member, and the like, and it is particularly preferably used as the transferring member. The image forming apparatus of the present invention is equipped with the above-mentioned conductive member, that is, a charging member, a developing member, a transferring member, a toner supplying member, a cleaning member and the like.

Next, an example in which the conductive member of the present invention is mounted on an image forming apparatus as a transfer member will be described.
FIG. 1 is an explanatory view showing an example of a transfer device in an image forming apparatus using a conductive member (transfer member) of the present invention, which is a transfer member of the present invention including a cored bar (not shown). A (transfer roller) 1 is brought into contact with an image forming body (photoreceptor) 2 via a recording medium (transfer material) 4 such as paper, and a power source 3 is provided between the transfer member 1 and the image forming body 2. The toner on the image forming body 2 is transferred to the recording medium 4 by applying a voltage and generating an electric field between the image forming body and the transfer member.

[0019]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 60 parts by weight of polyether polyol having a molecular weight of 5,000 in which propylene oxide and ethylene oxide are randomly added to glycerin, 40 parts by weight of polytetramethylene glycol having a molecular weight of 1,000, and 27 parts by weight of hexamethylene diisocyanate modified with isocyanurate. , 4 parts by weight of reactive silicone surfactant, 0.1 parts by weight of dibutyltin dilaurate, 0.4 parts by weight of modified aliphatic dimethylethylammonium ethosulfate were mixed with bubbles in a mixer, and the mixture was mixed with a diameter of Cast into a mold centered on a 6 mm metal shaft,
After curing at 5 ° C. for 5 hours, polishing was performed to prepare a urethane foam conductive roller having a diameter of 16.7 mm and a length of 215 mm.

The resistance position variation of the conductive roller is
Using a copper plate having a width of 1 cm, a total of 24 points were evaluated at 6 points at equal intervals in the longitudinal direction and 4 points at every 90 degrees in the circumferential direction. At the time of evaluation, both ends of the roller are pressed with a force of 500 gf,
The electric resistance between the core metal and the copper plate was measured. Temperature at the time of measurement,
Humidity was 20 ° C. and 55%, respectively. The measurement voltage at that time was 1,000V. The positional variation of the resistance was 0.14 in terms of the difference in the logarithmic value of the resistance between the portion having the highest resistance and the portion having the lowest resistance. The conductive roller was left in an environment of ozone concentration of 6 ppm and a temperature of 35 ° C. for 150 hours, and further left in an atmosphere of a temperature of 20 ° C. and a relative humidity of 50% for 24 hours, and then the above-mentioned digital force gauge was used.
After pressing a 2 mm aluminum flat plate with a force of 50 gf and then separating the flat plate at a speed of 10 mm / min, the maximum value of the tensile force was 0.1 gf or less, and it was confirmed that the roller surface was not melted. Next, after the conductive roller was allowed to stand at 90 ° C. for 72 hours, it was examined by the same method as described above whether or not the roller surface was melted. The maximum tensile force was 0.1 gf or less. It was confirmed that there was no. Further, after discharging the conductive roller at a temperature of 105 ° C. and a relative humidity of 100% for 3 hours, it was examined whether or not the roller surface was melted by the same method as described above, and the maximum tensile force was 0. It was confirmed that the melting point was 1 gf or less.

Example 2 A conductive roller was prepared in the same manner as in Example 1, except that 12 parts by weight of hexamethylene diisocyanate was used instead of 27 parts by weight of isocyanurate-modified hexamethylene diisocyanate. . When the variation in the resistance position of the conductive roller was evaluated in the same manner as in Example 1, the variation in the resistance position was 0 when the difference in the logarithmic value of the resistance between the portion having the highest resistance and the portion having the lowest resistance was 0.
It was 15. Also, after leaving the conductive roller in an environment of ozone concentration of 6 ppm and temperature of 35 ° C. for 150 hours,
When the roller surface was melted by the same method as in Example 1, it was confirmed that the maximum tensile force was 0.1 gf or less and the roller was not melted. Next, after leaving the conductive roller at a temperature of 90 ° C. for 72 hours, it was examined by the same method as described above whether or not the roller surface was melted. The maximum tensile force was 48.7 gf and the roller surface was It was confirmed that the melted. Furthermore, after the conductive roller was allowed to stand at a temperature of 105 ° C. and a relative humidity of 100% for 3 hours, it was examined by the same method as described above whether or not the roller surface was melted. As a result, the maximum tensile force was 0. It was confirmed that the melting point was 1 gf or less.

Example 3 In Example 1, 60 parts by weight of polyether polyol having a molecular weight of 5,000 obtained by randomly adding propylene oxide and ethylene oxide to glycerin as a polyol component and polytetramethylene glycol 40 having a molecular weight of 1,000 were used. Instead of 100 parts by weight, 100 parts by weight of a polyester polyol having a molecular weight of 2200 in which adipic acid and diethylene glycol are bonded is used, and the compounding amount of isocyanurate-modified hexamethylene diisocyanate is 2 parts.
A conductive roller was produced in the same manner as in Example 1 except that 21 parts by weight was used instead of 7 parts by weight. When the variation in the resistance position of the conductive roller was evaluated in the same manner as in Example 1, the variation in the resistance position was 0.13 when expressed by the difference in the logarithmic value of the resistance between the portion having the highest resistance and the portion having the lowest resistance. Met. Also, the conductive roller is set to have an ozone concentration of 6 pp.
After being left in an environment of m and temperature of 35 ° C. for 150 hours, it was examined by the same method as in Example 1 whether or not the roller surface was melted. The maximum value of the tensile force was 0.1 gf or less and it was not melted. Was confirmed. Next, after the conductive roller was allowed to stand at a temperature of 90 ° C. for 72 hours, it was examined whether or not the roller surface was melted by the same method as described above, and the maximum tensile force was melted at 0.1 gf. It was confirmed that not. Furthermore, when the conductive roller was allowed to stand at a temperature of 105 ° C. and a relative humidity of 100% for 3 hours, the roller surface was deformed and irregularities were formed. When the roller surface was melted by the same method as the above-mentioned method, it was confirmed that the maximum tensile force was 67.4 gf and the roller surface was melted.

Example 4 In the same manner as in Example 1 except that 1.0 part by weight of conductive carbon black was used in place of 0.4 part by weight of the modified aliphatic dimethylethylammonium ethosulfate in Example 1. A conductive roller was produced. When the variation in the resistance position of the conductive roller was evaluated in the same manner as in Example 1, the variation in the position of the resistance was 1.48 when expressed by the difference in the logarithmic value of the resistance between the portion having the highest resistance and the portion having the lowest resistance. Met. Also, the conductive roller is set to have an ozone concentration of 6 pp.
After leaving for 150 hours in an environment of m and a temperature of 35 ° C., whether or not the roller surface was melted was examined by the same method as in Example 1, and it was found that the maximum tensile force was 0.1 gf and it was not melted. It could be confirmed. Next, the conductive roller is heated to a temperature of 9
After standing at 0 ° C. for 72 hours, it was examined by the same method as described above whether the roller surface was melted. As a result, it was confirmed that the maximum tensile force was 0.1 gf or less, and the roller was not melted. Furthermore, after the conductive roller was allowed to stand at a temperature of 105 ° C. and a relative humidity of 100% for 3 hours, it was examined whether or not the roller surface was melted by the same method as described above, and the maximum tensile force was 0. It was confirmed that the melting point was 1 gf or less.

Comparative Example 1 In Example 1, 21 parts by weight of carbodiimide-modified diphenylmethane diisocyanate was used in place of 27 parts by weight of isocyanurate-modified hexamethylene diisocyanate, and 0.1 part by weight of dibutyltin dilaurate was used.
A conductive roller was produced in the same manner as in Example 1 except that the amount was 02 parts by weight. When the variation in the resistance position of the conductive roller was evaluated in the same manner as in Example 1, the variation in the resistance position was expressed by the difference between the logarithmic values of the resistance of the portion having the highest resistance and the resistance of the portion having the lowest resistance. Met. Also, after the conductive roller was left in an environment having an ozone concentration of 6 ppm and a temperature of 35 ° C. for 150 hours, it was examined by the same method as in Example 1 whether or not the roller surface was melted. It was confirmed that the roller surface melted at 56.8 gf. Next, the conductive roller is heated at a temperature of 90 ° C. for 72 hours.
After standing for a period of time, it was examined whether or not the roller surface was melted by the same method as described above, and it was confirmed that the maximum tensile force was 0.1 gf or less and the roller was not melted. Further, the conductive roller is set to a temperature of 105 ° C. and a relative humidity of 10
After being left at 0% for 3 hours, it was checked whether or not the roller surface was melted by the same method as described above, and it was confirmed that the maximum tensile force was 0.1 gf or less and the material was not melted.

Comparative Example 2 100 parts by weight of non-contaminating NBR, 5 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 0.6 part by weight of thiazole vulcanization accelerator,
Sulfenamide vulcanization accelerator 0.9 parts by weight, sulfur 2 parts by weight, oxybisbenzenesulfonyl hydrazide 5 parts by weight, sodium perchlorate 0.1 parts by weight were mixed in a Banbury mixer, and the mixture was heated to 150 ° C. Heated to 6m in diameter
m cast into a mold centered on a metal shaft, vulcanized at 150 ° C for 10 minutes and then polished to a diameter of 16.
A 7 mm long 215 mm long NBR foam conductive roller was prepared. Variation in resistance position of the conductive roller
When evaluated in the same manner as in Example 1, the positional variation of the resistance was 0.16 in terms of the difference in logarithmic value of the resistance between the portion having the highest resistance and the portion having the lowest resistance. In addition, the conductive roller is placed in an environment with an ozone concentration of 6 ppm and a temperature of 35 ° C.
After standing for 50 hours, whether or not the roller surface was melted was examined by the same method as in Example 1. As a result, the maximum tensile force was 61.4 gf, and it was confirmed that the roller surface was melted. Next, after the conductive roller was left at a temperature of 90 ° C. for 72 hours, it was examined whether or not the roller surface was melted by the same method as described above, and the maximum tensile force was 0.
It was confirmed that the melting point was 1 gf or less. Furthermore, the conductive roller is set to a temperature of 105 ° C. and a relative humidity of 100.
After standing for 3 hours at%, whether or not the roller surface was melted was examined by the same method as described above. As a result, it was confirmed that the maximum tensile force was 0.1 gf or less and the roller was not melted.

Comparative Example 3 60 parts by weight of polyether polyol having a molecular weight of 5,000 in which propylene oxide and ethylene oxide were randomly added to glycerin, 40 parts by weight of polytetramethylene glycol having a molecular weight of 1,000, and modified diphenylmethane diisocyanate 20.8. Parts by weight, reactive silicone surfactant 4 parts by weight, dibutyltin dilaurate 0.02
Parts by weight and 0.4 parts by weight of modified aliphatic dimethylethylammonium ethosulfate are mixed while mixing air bubbles with a mixer, and the mixture is cast into a mold centered on a metal shaft with a diameter of 6 mm, Cured at ℃ for 5 hours and then polished, diameter 16.7mm and length 215m
m urethane foam conductive roller was produced. The resistance value of the conductive roller at room temperature was 10 ^8.27 Ω, which was a resistance value suitable as a medium resistance conductive member. Also, after the conductive roller was left in an environment having an ozone concentration of 6 ppm and a temperature of 35 ° C. for 150 hours, it was examined by the same method as in Example 1 whether or not the roller surface was melted. It was confirmed that the roller surface melted at 16.5 gf. Next, the conductive roller is heated at a temperature of 90 ° C. for 72 hours.
After standing for a period of time, it was examined whether or not the roller surface was melted by the same method as described above, and it was confirmed that the maximum tensile force was 0.1 gf or less and the roller was not melted. Further, the conductive roller is set to a temperature of 105 ° C. and a relative temperature of 10
After being left at 0% for 3 hours, it was checked by the same method as described above whether or not the roller surface was melted. As a result, it was confirmed that the maximum tensile force was 0.1 gf or less and the roller was not melted. Further, it was confirmed that the amount of extracted acetone was 10% by weight or less even after the test, and no hydrolysis was performed. Furthermore, a conductive roller whose surface was melted after the ozone durability test was installed as a transfer roller in a commercially available laser printer, and the temperature and humidity were 15 ° C and 10%, respectively, in a grayscale environment.
When a black solid image and a white solid image were printed, a good image was not obtained. Furthermore, temperature and humidity are 32.5 ° C,
When a grayscale image, a black solid image, and a white solid image were printed in an environment of 85%, a good image was not obtained.

Comparative Example 4 A conductive roller was produced in the same manner as in Comparative Example 3 except that aluminum hydroxide powder was further added to the compounding ingredients of Comparative Example 3. The resistance value of the conductive roller at room temperature is 10
^It had a resistance value of ^8.29 Ω and was suitable as a medium resistance conductive member. Also, the conductive roller is set to have an ozone concentration of 6 pp.
After being left for 150 hours in an environment of m and a temperature of 35 ° C., whether or not the roller surface was melted was examined by the same method as in Example 1. The maximum tensile force was 16.0 gf and the roller surface was melted. Was confirmed. Next, after leaving the conductive roller at a temperature of 90 ° C. for 72 hours, it was examined whether or not the roller surface was melted by the same method as described above, and the maximum tensile force was 0.1 gf or less. It was confirmed that they did not. Further, the conductive roller is heated to a temperature of 1
After being left at 05 ° C. and 100% relative humidity for 3 hours, it was examined whether or not the roller surface was melted by the same method as the above-mentioned method. The maximum tensile force was 0.1 gf or less and it was not melted. I was able to confirm that. Further, it was confirmed that the amount of extracted acetone was 10% by weight or less even after the test, and no hydrolysis was performed. Furthermore, after the ozone durability test, a conductive roller whose surface was melted was incorporated into a commercially available laser printer as a transfer roller, and the temperature and humidity were 15 ° C and 10%, respectively.
When printing grayscale, black solid, and white solid images in this environment, good images were not obtained. Further temperature,
When a grayscale, black solid, and white solid image was printed in an environment where the humidity was 32.5 ° C. and 55%, respectively, a good image was not obtained.

[0028]

EFFECTS OF THE INVENTION The conductive member of the present invention has excellent ozone resistance, and also has excellent heat resistance and moist heat resistance. It is less likely to contaminate the body and gives a good image.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a transfer device in an image forming apparatus using a conductive member of the present invention.

[Explanation of symbols]

1: Transfer member (transfer roller) 2: Image forming body (photoreceptor) 3: Power supply 4: Recording medium (transfer material)

Front page continuation (51) Int.Cl. ⁷ Identification code FI G03G 15/02 101 G03G 15/02 101 15/08 501 15/08 501D 15/16 103 15/16 103 H01B 1/20 H01B 1/20 Z // (C08G 18/48 C08G 18/48 101: 00) 101: 00 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08L 75/04-75/12

Claims (5)

(57) [Claims] 1. A roller-shaped conductive member using a polyurethane material, wherein the polyurethane material mainly contains a polyol component and at least one selected from saturated aliphatic polyisocyanates and isocyanurate modified products thereof. A polyurethane material produced from a polyisocyanate component and mixed with an ionic conductive agent which is a quaternary ammonium salt of a carboxylic acid or an alkylsulfuric acid, having an ozone concentration of 6 ppm and a temperature of 35 ° C.
When a flat plate of 12 mm in diameter was pressed with a force of 50 gf for 20 seconds on a member that had been left for 24 hours in an atmosphere of a temperature of 20 ° C. and a relative humidity of 50% after the plate was pulled apart at a speed of 10 mm / min. The maximum value of the tensile force of 1 is not more than 1 gf, and the transfer member made of a conductive urethane foam. 2. The polyurethane material is magnesium oxide
The electroconductive urethane foam transfer member according to claim 1, which contains 0.1 to 10% by weight. 3. The polyurethane material is 72 at a temperature of 90.degree.
The composition which does not substantially melt even when left for a time.
Alternatively, the transfer member made of the conductive urethane foam described in 2. 4. The conductive urethane foam according to claim 1, wherein the polyurethane material is one that does not melt or hydrolyze even when left for 3 hours in an environment of a temperature of 105 ° C. and a relative humidity of 100%. Made transfer member. 5. An image forming apparatus equipped with the conductive urethane foam transfer member according to claim 1.