JP4790477B2 - Toner supply roller - Google Patents

Description

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

  Conventionally, in an image forming apparatus such as a copying apparatus, a printer, or a facsimile, a toner image is developed by developing an electrostatic latent image formed on an image carrier made of an electrophotographic photosensitive member or an electrostatic recording derivative with a developing device. It has been made visible as. In such a developing device, a toner supply roller composed of a soft elastic roller for supplying a predetermined toner (developer) accommodated in the hopper to the image carrier side is incorporated.

  As the toner supply roller, a foamed elastic roller having a foamed elastic layer made of polyurethane foam (sponge) is generally used.

  On the other hand, with respect to the toner supplied by the toner supply roller, a toner having a small particle size and a low melting point tends to be used in recent years because of the need for improving the image quality and the printing speed. As a result, the toner is more likely to aggregate due to charging or standing for a long time. For this reason, the toner that has aggregated and adhered to the developing roller cannot be scraped off by the toner supply roller, and the surface of the developing roller Residual (toner filming) is becoming easier. Due to this, unevenness on the image appears, and ghost or the like may occur. That is, the toner supply roller is pressed against the developing roller, and is rotated in the same direction as the developing roller. As a result, the toner adhering to the surface of the developing roller is scraped and removed by the toner supply roller at the contact portion between the two rollers, while the toner is newly supplied uniformly on the developing roller. It has become. At this time, if the toner aggregated and adhered on the developing roller is not removed well by the scraping action by the toner supply roller, a filming phenomenon of the toner remaining on the developing roller is caused as it is. For this reason, the distribution of the toner involved in image formation on the developing roller becomes non-uniform, causing unevenness on the image as a ghost or the like.

Measures have been proposed for improving the toner scraping property of the toner supply roller (Patent Document 1 and Patent Document 2). That is, the rugged structure is formed by a plurality of ridges extending in the circumferential direction of the roller with a gear-shaped cross section provided so that the outer peripheral surface of the urethane foam layer extends linearly or spirally parallel to the rotation axis in the rotation axis direction. It is said. Thereby, toner scraping on the developing roller is improved. In addition, the scraped toner is positively discharged from the roller, thereby eliminating the ghost caused by the toner remaining on the developing roller, and suppressing the occurrence of scratches due to wear of the developing roller and the promotion of toner deterioration. . In addition, when the gear shape on the roller surface is provided so as to form a spiral shape with a series of gear-shaped tooth tips (or tooth bottoms) in the longitudinal direction of the core bar, scraping of the toner on the developing roller is extremely advantageous. (Patent Document 3).
JP 05-61350 A Japanese Patent No. 0283716 JP 2000-056556 A

  However, according to studies by the present inventors, toner scraping may not be performed satisfactorily even if a roller having a gear-shaped cross section as described above is used.

  Since such a roller has a concavo-convex structure on the roller surface, the gear convex part (tooth tip), especially the corner part of the convex part, scrapes off the toner well, but the roller crushes the gear concave part (tooth bottom). Since it rotates and scrapes off the toner, the scraping performance is lower than that of the gear projection. Further, since the corners of the convex portions are pressed more strongly, the toner scraping performance in the roller circumferential direction may be uneven. For this reason, density unevenness may occur at the uneven pitch on the roller surface on the image, and the occurrence of streaky unevenness is also a concern. As a result, it may be difficult to always obtain a stable and high-quality image.

  The object of the present invention is to stabilize the toner supply and scraping properties to the developing roller, in particular to make the toner scraping more uniform and uniform, thereby suppressing the occurrence of image abnormalities such as density unevenness, suppressing toner deterioration, It is an object of the present invention to provide a toner supply roller that can always obtain a stable and high-quality image.

  As a result of repeated studies to achieve the above object, it has been found that the gear shape of the roller cross section and the helical shape formed by the continuous gear shape affect the toner scraping property and the like. For example, the inventors have found that the angle formed by the spiral-shaped spiral with respect to the longitudinal direction of the core bar and the pitch of the gear shape affect the toner scraping property. The present invention has been made based on these findings. Further, it has been found that the toner scraping property and the like are superior when the convex portion of the gear-shaped tooth tip has a corner and is round with no corner.

According to the present invention, in a toner supply roller having a cored bar and a foamed elastic layer formed on the outer peripheral surface of the cored bar,
The foamed elastic layer is cross-sectional to Cartesian to the longitudinal direction of the metal core has a gear shape,
A spiral shape is formed by a series of gear-shaped tooth tips,
An angle formed by the longitudinal direction and the spiral shape is 0.3 ° or more and 10 ° or less, and
A toner supply roller is provided in which the pitch width of the gear shape is 0.3 mm or more and 1.0 mm or less.

  According to the present invention, the toner supply and scraping properties to the developing roller are stabilized, and in particular, the toner scraping is made more uniform and uniform, thereby suppressing the occurrence of image abnormalities such as density unevenness, suppressing toner deterioration, and being always stable. A toner supply roller that can obtain a high-quality image is provided.

[First embodiment]
The toner supply roller of this embodiment is a toner supply roller having a cored bar and a foamed elastic layer formed on the outer peripheral surface of the cored bar,
Of the foamed elastic layer, cross section Cartesian the longitudinal direction of the metal core has a gear shape,
A spiral shape is formed by a series of gear-shaped tooth tips,
The angle formed by the longitudinal direction of the cored bar and the spiral shape is not less than 0.3 ° and not more than 10 °, and
The pitch width of this gear shape is 0.3 mm or more and 1.0 mm or less.

  Hereinafter, this embodiment will be described in more detail with reference to the drawings.

  As shown in FIG. 1, the foamed elastic body layer 1 used in the present invention has a gear shape in a cross section perpendicular to the longitudinal direction of a cored bar 2 serving as a rotation axis. In addition, as shown in FIG. 2, an angle (inclination angle) θ formed by a spiral shape formed by a series of gear-shaped tooth tips (or tooth bottoms) with respect to the longitudinal direction of the core metal is 0.3 ° to 10 °. Yes, preferably 0.5 ° to 5.0 °. When the toner supply roller is pressed against the developing roller and rotates, the toner scraping property on the developing roller is improved.

  In order to suppress unevenness in toner scraping on the developing roller in the circumferential direction of the roller and to prevent density unevenness from occurring on the uneven surface pitch of the roller surface on the image, the spiral inclination angle θ is 0.3 ° or more. Preferably, the angle is 0.5 ° or more. Further, from the viewpoint of preventing the toner from easily staying in the gear-shaped tooth bottom and promoting the deterioration (fine graining) of the toner, thereby preventing the occurrence of abnormal charging, the inclination angle θ is 10 ° or less, Preferably it is 5 degrees or less. About the measuring method of inclination-angle (theta), it can measure using a three-dimensional measuring machine, an optical microscope, etc., can measure 10 places arbitrarily from a roller outer periphery, and can make the average value into inclination-angle (theta).

  The pitch width 4 (shown in FIG. 3) of the gear shape is 0.3 mm to 1.0 mm. From the viewpoint of obtaining an effect of improving the toner scraping property by the gear shape, the pitch width is set to 0.3 mm or more. In addition, the pitch width is set to 1.0 mm or less from the viewpoint of suppressing unevenness in toner scraping on the developing roller in the circumferential direction of the roller and preventing density unevenness from occurring on the uneven surface pitch of the roller surface on the image. . About the measuring method of pitch width, it can measure with a projector, an optical microscope, a three-dimensional measuring device, etc.

[Second form (for reference) ]
The toner supply roller of this embodiment which is a reference form is a toner supply roller having a cored bar and a foamed elastic layer formed on the outer peripheral surface of the cored bar,
Of the foamed elastic layer, cross section Cartesian the longitudinal direction of the metal core has a gear shape,
A spiral shape is formed by a series of gear-shaped tooth tips,
This gear-shaped tooth tip has a round shape with a radius of 0.1 mm or more.

  Hereinafter, this embodiment will be described in more detail with reference to the drawings.

  As shown in FIG. 1, the foamed elastic layer 1 has a gear shape in cross section perpendicular to the longitudinal direction of the cored bar 2 serving as a rotation axis. A helical shape is formed by a series of gear-shaped tooth tips. The gear-shaped tooth tip 3 (shown in FIG. 3) has a round shape with a radius R of 0.1 mm or more.

  When such a toner supply roller rotates with its outer peripheral surface being pressed against the developing roller, the toner scraping property of the developing roller on the developing roller in the circumferential direction of the roller that may occur due to the uneven surface structure. Unevenness is improved. Furthermore, when used for a long period of time, it is possible to prevent the omission of the roller surface, the breakage of the shape, or the like that may occur when the tooth tip 3 is strongly pressed by the developing roller.

  If the tooth tip 3 has a rounded shape with a radius R of 0.1 mm or more, preferably 0.3 mm or more, unevenness in toner scraping on the developing roller in the circumferential direction of the roller is suppressed, and the roller surface is displayed on the image. It is possible to prevent density unevenness from occurring with the uneven pitch. Further, it is possible to prevent the toner from being excessively stressed, to suppress the deterioration (fine-graining) of the toner, and to prevent the occurrence of image defects such as a decrease in density and scumming even during long-term use. .

  The radius of the round shape can be obtained by enlarging the tooth tip portion with a projector, an optical microscope, a three-dimensional measuring device, or the like, and measuring the radius of the corner portion.

  A toner supply roller having the features of both the first form and the second form is preferable because the effect of the present invention is remarkably obtained.

(Tooth width, root width, tooth height)
In the present invention, the gear-shaped tooth tip width 5 is preferably 0.1 mm or more and 0.5 mm or less, and the tooth root width 5 is preferably 0.05 mm or more and 0.5 mm or less. As shown in FIG. 2, the tooth tip width referred to here is determined as the distance between the extended line intersections of the substantially flat portion of the gear tooth tip and the side surface portion of the gear convex portion. The tooth bottom width 6 is determined as a distance between the extended line intersections between the substantially flat portion of the gear tooth bottom and the side surface portion of the gear convex portion.

  When the gear tooth tip width 5 is 0.1 mm or more, even if the frictional resistance with the developing roller is large or the amount of toner to be scraped off is large, the convex portion (tooth tip) is missing and the electrophotographic system It is possible to excellently suppress the occurrence of a foreign matter such as clogging in other parts and the cause of an image defect or failure. When the gear tooth tip width is 0.5 mm or less, it is possible to excellently prevent unevenness in toner scraping on the developing roller, and it is possible to excellently prevent image defects such as image unevenness and ghost. Further, when the gear tooth bottom width 6 is 0.05 mm or more, it is possible to excellently prevent the toner discharged from the developing roller from being blocked in the concave portion. When the gear tooth bottom width is 0.5 mm or less, unevenness in toner scraping on the developing roller can be excellently prevented. Furthermore, the tooth height 7, which is the height from the tooth bottom to the tooth tip, is preferably 0.05 mm to 1.0 mm. When the tooth height 7 is 0.05 mm or more, it is excellently prevented that the roller surface has a gentle uneven structure and the toner scraping of the entire roller is reduced. When the tooth height is 1.0 mm or less, it is possible to excellently prevent unevenness in the frictional charge amount of the toner due to a large pressure difference between the tooth tip and the root of the developing roller, and uneven pitch appears on the image. Excellent prevention.

[Relationship between tip width and root width]
In the present invention, when the gear tooth tip width 5 is X and the gear tooth bottom width 6 is Y, the ratio of the tooth tip width to the sum of the tooth tip width and the tooth bottom width preferably satisfies the following equation.

  When the ratio is preferably 20% or more, and more preferably 40% or more, the toner scraping performance of the entire roller is excellent, and it becomes excellent and easy to obtain a high-quality image. When the ratio is preferably 90% or less, more preferably 70% or less, the toner scraping property is excellent, the rubbing force against the developing roller is suppressed, and the effect of preventing toner deterioration is excellent.

[Molds etc.]
In addition, in order to form the foamed elastic layer having the above-mentioned gear shape, an appropriate mold forming technique can be used. A mold having a desired mold inner surface shape can be obtained by transferring the shape to the inner surface of the mold by electroforming plating or by transferring the shape by casting. Furthermore, the pipe mold is vertically divided into two parts, and electric discharge machining is performed on each inner surface using an electrode of the desired inner surface shape of the mold, and then the divided pipe molds are joined or joined. It is also possible to obtain a mold for forming the gear shape by using it as a vertically divided mold without doing so.

  As the metal core, a metal core used for a known toner supply roller can be appropriately selected and used. A metal cylinder can be used as the core metal. At this time, the longitudinal direction of the cored bar coincides with the direction in which the central axis of the cylindrical body extends.

[Foamed elastic layer]
In the present invention, it is preferable that the foamed elastic layer formed on the outer peripheral surface of the core metal is a layer made of polyurethane foam (polyurethane foam layer).

  In particular, a polyurethane foam layer having a hardness of 100 g / mm to 750 g / mm is preferable. When the hardness is 100 g / mm or more, it is possible to excellently prevent the toner scraping property from being lowered due to a small rubbing force (friction force) with the developing roller. Further, when the hardness is 750 g / mm or less, it is possible to excellently prevent the rubbing force with the developing roller from being increased, causing the developing roller to be worn or damaged, or to cause toner deterioration.

  In order to measure the hardness of the toner supply roller having the core metal 2 and the elastic foam layer 1, a jig 8 having a flat pressing surface with a length of 50 mm and a width of 10 mm is used as shown in FIG. This jig is pressed against the surface of the toner supply roller at a speed of 10 mm / min, and the load applied to the roller surface when the foamed elastic layer is deformed by 1 mm is measured. The measurement points at this time are 3 points in the longitudinal direction of the roller, and 4 points in the circumferential direction for 3 points in the longitudinal direction, for a total of 12 points. The arithmetic average of the load (the load when the elastic layer is deformed by 1 mm) at these 12 locations is defined as the hardness.

  Each open cell on the surface of the polyurethane foam layer, which is a foamed elastic layer, preferably has an open diameter of 100 μm or more and 800 μm or less.

  When the opening diameter is 100 μm or more, it is possible to excellently prevent the possibility of causing a decrease in density and generation of streaks due to a decrease in toner supply amount. When the opening diameter is 800 μm or less, it is possible to excellently prevent the gear shape from becoming difficult to form. As for the measurement method of the aperture diameter, the surface image can be taken with a real-time scanning laser microscope at a magnification of 50 times, 50 cell diameters can be randomly read, and the average value can be calculated as the aperture diameter.

  The total area of the open cells on the surface of the polyurethane foam layer is preferably 20% to 90% of the surface area of the polyurethane foam layer. At this time, it is more preferable that the openings exist as uniformly as possible on the surface of the polyurethane foam layer.

  When the total opening area of the cell opening is 20% or more of the surface area of the polyurethane foam layer, the toner supply performance is lowered, and the toner is easily clogged inside the polyurethane foam layer, thereby causing partial curing. It is possible to excellently prevent image deterioration. Further, by setting it to 90% or less, it is possible to excellently suppress the possibility of occurrence of fuzz or omission on the roller surface and the resulting image defect.

[Polyurethane foam layer]
The composition of the polyurethane foam layer can be appropriately selected from known polyurethane foam compositions. In the production of this polyurethane foam, a material containing a polyol component, a polyisocyanate component, a foaming agent and optionally used conductivity imparting agent, catalyst, foam stabilizer and the like is used as a polyurethane foam forming material.

  As a polyol, it can select and use suitably from conventionally well-known various polyols. Examples of this polyol include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylene adipate (PHA), a copolymer of ethylene adipate and butylene adipate, dimer acid polyol, castor oil polyol, polycaprolactone Examples include polyester polyols such as polyols and polyether polyols such as polyoxyalkylene glycols. Further, it may be used as a prepolymer previously polymerized with polyisocyanate.

  As polyisocyanate, it can be used by appropriately selecting from various known polyisocyanates. Examples of this polyisocyanate include aromatic polyisocyanates and derivatives thereof such as toluene diisocyanate and diphenylmethane diisocyanate, aliphatic polyisocyanates and derivatives thereof such as hexamethylene diisocyanate, and alicyclic polyisocyanates and derivatives thereof such as isophorone diisocyanate. Can be mentioned.

  Examples of foam stabilizers that can be used together with polyisocyanate and polyol include water-soluble polyether siloxane from polydimethylsiloxane and EO / PO copolymer, sodium salt of sulfonated ricinoleic acid, and polysiloxane / polyoxyalkylene. Examples thereof include a mixture with a copolymer. Among these, water-soluble polyether siloxane is suitable as the polyether polyol-based foam stabilizer.

  Examples of blowing agents that can be used with polyisocyanates, polyols include water, trichloromonofluoromethane, dichlorodifluoromethane, methylene chloride, trichlorofluoromethane, n- and iso-pentane, in particular industrial mixtures thereof, n- And liquid hydrocarbons such as iso-butane and propane, ethers such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone, alkyl esters of carboxylic acids such as methyl formate, dimethyl oxalate and ethyl acetate Etc., carbon dioxide and the like. These can be used alone or in combination. Especially, it is preferable to use water independently from a viewpoint of reducing the load given to an environment.

  As a catalyst, it can select from a well-known polyurethane catalyst suitably. For example, amine catalysts include 1,2-dimethylimidazole, triethylamine, tripropylamine, tributylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, diethylenetriamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N′-tetramethylbutanediamine, N, N, N ′, N′— Tetramethyl-1,3-butaneamine, N, N, N ′, N′-tetramethylhexamethylenediamine, bis [2- (N-N-dimethylamino) ethyl] ether, N, N-dimethylbenzylamine, N , N-dimethylcyclohexylamine, N, N, N ′, N ′, N ″, N ″ -pentamethy Diethylenetriamine, triethylenediamine, salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5-diazabicyclo (4,3 , 0) Nonene-5, azacyclo compounds such as N, N-dialkylpiperazines, various N, N ′, N ″ -trialkylaminoalkylhexahydrotriamines, etc. , Tin acetate, tin octylate, tin octetate, tin oleate, tin laurate, dibutyltin dichloride, dibutyltin dilaurate, dibutyltin diacetate, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetrakis (2 -Ethylhexyloxy) titanium, lead naphthenate, dinaphthenate Kell, there are cobalt naphthenate and the like, there is the amine catalysts and organometallic catalyst initial activity organic salt catalysts obtained by reduction of (carboxylate or borate salts).

  Further, the structure of the crosslinking agent to be used is not particularly limited, but diols such as alkylene glycol and 1,4-butanediol (1,4BD), triols such as glycerin and trimethylolpropane (TMP), Tetraols such as pentaerythritol, diamines such as ethylenediamine (EDA), amino alcohols such as diethanolamine (DEA), triethanolamine (TEA), and the like can be used alone or in combination.

  As a conductive material for imparting conductivity as necessary, a general conductivity imparting agent can be used, and for example, an ion conductive substance can also be used. Examples of the ionic conductive agent include quaternary ammonium salts, which are used alone or in combination.

  As other additives, flame retardants, colorants, antioxidants, ultraviolet absorbers, antioxidants, antioxidants, foam breakers and the like can be used as necessary.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Examples A1 to A14, Comparative Examples A1 to A3]
In each of the examples and comparative examples, first, a molding die was prepared by processing the inner surface of the metal pipe so as to have a gear shape as shown in Table 1.

On the other hand, a polyurethane foam layer was employed as the foamed elastic layer. The following materials were mixed and used as the raw material for the polyurethane foam layer.
FA-908 (trade name, polyether polyol manufactured by Sanyo Chemical Co., Ltd.) 100 parts by weight.
0.5 parts by weight of diethanolamine.
1 part by weight of L5366 (trade name. Silicone foam stabilizer manufactured by Nippon Unicar Co., Ltd.).
0.1 part by weight of ToyoCat-ET (trade name; tertiary amine catalyst manufactured by Tosoh Corporation).
TEDA-L33 (trade name, tertiary amine catalyst manufactured by Tosoh Corporation) 0.5 parts by weight.
2 parts by weight of water (foaming agent).
29.5 parts by weight of T80 (trade name. Isocyanate manufactured by Mitsui Takeda Chemical Co., Ltd., NCO% = 48).
7.4 parts of M200 (trade name. Isocyanate manufactured by Mitsui Takeda Chemical Co., Ltd., NCO% = 31).

  From these raw materials, a roller having the hardness, cell opening diameter, and total opening area / surface area ratio shown in Table 1 was obtained.

  The raw material in each example is poured into each molding die preheated to a temperature of 60 to 80 ° C., cured at the same temperature for 10 to 20 minutes, removed from the molding die, and the core metal 2 serving as a rotating shaft. A urethane foam layer was integrally formed around the periphery, and each example toner supply roller having the structure shown in FIG. 1 was manufactured. The core metal used at this time is a cylindrical shape having a diameter of 5.0 mm.

  Then, an image evaluation test using the obtained toner supply roller of each example is performed, and density unevenness and solid density uniformity at the uneven pitch of the roller surface are respectively examined on the image. It was shown to.

  In addition, evaluation of density unevenness at the uneven pitch in the image evaluation test was performed as follows. First, after setting the toner cartridge in which each toner supply roller is incorporated into a commercially available copying machine, it is set and 4% printing is performed by imaging in an environment of 15 ° C. and 10% relative humidity. Each was performed 6000 sheets. Further, a halftone image was printed, and the presence or absence of density unevenness at the uneven pitch was examined. Five levels of sensory evaluation were performed on the level of density unevenness. In the evaluation, ◯ indicates that the occurrence of density unevenness at the uneven pitch is not observed, while X indicates that the occurrence is remarkable, and the interval between them is divided into five stages. In order of good evaluation, ◯, ○ Δ, Δ, Δx, and x were used (the same applies to other five-level evaluations).

  In addition, the solid density uniformity evaluation was performed by imaging in an environment of 15 ° C. and a relative humidity of 10%. That is, after 60000 printouts of 4% were performed, a solid black copy was taken at the maximum density, and the printed solid image was visually evaluated. At this time, density unevenness at the uneven pitch was ignored. In the evaluation, ◯ indicates that the density is uniform and good, while X indicates that the density is non-uniform and the occurrence of density unevenness is remarkable, and the interval is divided into five levels.

  As is clear from the results of Tables 1 and 2, in Examples A1 to A5, excellent results were obtained in the image evaluation indicated by density unevenness and solid density uniformity at the uneven pitch. That is, it was recognized that the toner scraping property and the toner supply property were excellent, and a high-quality image could be obtained. In Examples A6 and A9, there was no density unevenness at the uneven pitch, and the solid density uniformity was slightly inferior to Example A1, but good results were obtained. Further, in Examples A7 and A8, when the roller surface was observed after the test was completed, a portion where the gear convex portion (tooth tip) was about to be lost was observed, but density unevenness and solid density uniformity occurred at the uneven pitch. With respect to, a good result was obtained although it was slightly inferior to Example A1.

  In Example A10, since the foamed elastic layer has a slightly low hardness, the sliding force with the roller tends to decrease and the toner scraping property tends to decrease. The density uniformity was slightly inferior. In Example A11, since the foamed elastic layer has a slightly high hardness, the frictional force with the roller is increased and the toner is slightly deteriorated. Therefore, the solid density uniformity is slightly higher than that of Example A1. The result was inferior. However, in both cases, there was no density unevenness at the uneven pitch, and there was no problem for normal use. Good results were also obtained in Examples A12, A13, and A14. In Example A15, when the roller surface after evaluation was observed, there was a portion where fuzzing or gear protrusions (tooth tips) were almost missing, but density unevenness and solid density uniformity at the uneven pitch. The occurrence of was good, although slightly inferior to Example A1.

  In Comparative Examples A1 and A3, there was uneven toner scraping in the roller circumferential direction, and density unevenness at the uneven pitch was noticeable. In Comparative Example A2, toner deterioration was promoted and the solid density was non-uniform.

[Examples B1 to B14, Comparative Examples B1 to B3]
The examples shown here are for reference only.
First, the following were mixed as a mixed polyol.
FA-908 (trade name, polyether polyol manufactured by Sanyo Chemical Co., Ltd.) 100 parts by weight.
0.5 parts by weight of diethanolamine.
1 part by weight of L5366 (trade name. Silicone foam stabilizer manufactured by Nippon Unicar Co., Ltd.).
0.1 part by weight of ToyoCat-ET (trade name; tertiary amine catalyst manufactured by Tosoh Corporation).
TEDA-L33 (trade name, tertiary amine catalyst manufactured by Tosoh Corporation) 0.5 parts by weight.
2 parts by weight of water (foaming agent).

The following isocyanate was mixed with this mixed polyol so as to have an NCO index of 100 and stirred.
29.5 parts by weight of T80 (trade name. Isocyanate manufactured by Mitsui Takeda Chemical Co., Ltd., NCO% = 48).
7.4 parts of M200 (trade name. Isocyanate manufactured by Mitsui Takeda Chemical Co., Ltd., NCO% = 31).

  The obtained mixture is poured into a molding die and heated at a temperature of 60 ° C. to perform foam molding. As shown in FIG. 1, the foamed elastic body layer 1 is formed around the core metal 2 serving as a rotating shaft. A toner supply roller formed integrally was manufactured.

  At that time, a mold having an uneven structure (gear shape) on the inner surface of the mold was used. As shown in FIG. 1, the concave-convex structure of the mold has a gear-shaped cross section perpendicular to the longitudinal direction, and a foamed elastic layer having a helical shape formed by a series of gear-shaped tooth tips in the longitudinal direction is obtained. The structure. At this time, the uneven structure of the mold is adjusted in each example, and the radius R of the tip of the tooth, the tip width 5, the root width 6, the tooth height 7, {X / (X + Y)} × 100% (X: The calculated value derived from the tooth tip width (Y: root width) was set to the values shown in Table 3.

  Moreover, about the comparative example B2, it shape | molded using the shaping | molding die whose shaping | molding die inner surface is cylindrical shape (non-uneven structure). In Comparative Example B3, the toner supply roller was molded by the above method and sufficiently aged, and then the roller surface was polished.

  In each of the obtained toner supply rollers of each example, the foamed elastic layer had a hardness of 200 g / mm, a cell opening diameter of 300 to 700 μm, and a cell opening ratio of 65%.

  Then, an image evaluation test using the obtained toner supply roller of each example is performed, and the ghost occurrence state and the solid density uniformity (density unevenness at the uneven pitch of the roller surface) are respectively examined, and the results are obtained. It is shown in Table 4.

  The evaluation of the presence or absence of ghost generation in the image evaluation test was performed as follows. First, a toner cartridge incorporating the toner supply roller of each example can be installed in a commercially available copying machine and then set, and 4% printing is performed by imaging in an environment of 15 ° C. and 10% relative humidity. Each was performed 6000 sheets. Further, a ghost evaluation image was drawn to examine whether a ghost phenomenon occurred. In addition, the sensory evaluation of 5 steps | paragraphs was implemented about the ghost level. In the evaluation, ◯ indicates that no occurrence of ghost is observed, while × indicates that the occurrence of ghost failure is remarkable, and the interval between them is divided into five levels.

  In addition, the solid density uniformity evaluation was performed by imaging in an environment of 15 ° C. and a relative humidity of 10%. That is, after 60000 printouts of 4% were performed, a solid black copy was taken at the maximum density, and the printed solid image was visually evaluated. In the evaluation, ◯ indicates that the occurrence of density unevenness is good, while x indicates that the occurrence of density unevenness is remarkable, and there are five levels between them.

  As is clear from the results shown in Tables 3 and 4, in Examples B1 and B2, excellent results were obtained in image evaluation indicated by ghost and density uniformity, and excellent toner scraping property and toner discharge. Sex is recognized. In particular, in Example B2, there was no density unevenness and a high-quality image could be obtained. Further, in Example B3, when the roller surface was observed after the test was completed, a portion where the gear convex portion (tooth tip) was missing was observed, but the occurrence of density unevenness was slightly inferior to that in Example B1. Good results. In Example B4, the toner scraping tendency tended to be slightly lowered, but the result was relatively good. Furthermore, in Examples B5 to B8, density unevenness was observed at the uneven pitch due to the gear shape, and the density uniformity was slightly inferior to that of Example B1, but in both cases the occurrence of ghosts There was no problem for normal use. In Examples B9 and 10, good results were obtained although both ghost and density uniformity were slightly inferior to Example B1. In Example B11, ghosting was slightly observed, but there was no problem in density uniformity, and the result was good. Even in Example B12, there was a portion where the gear convex portion (tooth tip) on the roller surface was missing, and there was partial unevenness in density uniformity, but there was almost no ghosting and good results. there were. Further, in Example B13, since the tooth tip width was slightly narrow, the scraping property of the toner tended to be reduced, and some density unevenness was observed, but the result was relatively good. Further, in Example B14, the rubbing force against the developing roller tends to increase, and toner deterioration tends to occur slightly. However, although ghosting is slightly inferior to Example B1, good results are obtained. It was.

  In Comparative Example B1, there was no problem with the ghost, but some unevenness in the uneven pitch on the roller surface was seen in the solid image. Further, in Comparative Examples B2 and B3, remarkable ghost and density unevenness were observed. In particular, in Comparative Example B3, when the roller surface was observed, the fuzz was severe and many portions where the surface was almost missing were observed.

FIG. 3 is a schematic bird's-eye view for explaining the toner supply roller of the present invention. It is a typical partial bird's-eye view for demonstrating helical shape. It is a typical fragmentary sectional view for explaining a gear shape. 4A and 4B are schematic diagrams for explaining a method for measuring the hardness of the foamed elastic layer of the toner supply roller, where FIG. 5A is a plan view and FIG. 5B is a side view.

Explanation of symbols

1: Foam elastic body layer 2: Core metal 3: Gear-shaped tooth tip portion 4: Tooth pitch width 5: Gear tooth tip width 6: Gear tooth bottom width 7: Height from the tooth bottom to the tooth tip R: Gear R-shaped radius of tooth tip 8: Push plate jig of hardness measuring device θ: Angle formed by spiral with metal core longitudinal direction

Claims (8)

In a toner supply roller having a cored bar and a foamed elastic layer formed on the outer peripheral surface of the cored bar,
The foamed elastic layer is cross-sectional to Cartesian to the longitudinal direction of the metal core has a gear shape,
A spiral shape is formed by a series of gear-shaped tooth tips,
An angle formed by the longitudinal direction and the spiral shape is 0.3 ° or more and 10 ° or less, and
A toner supply roller having a pitch width of the gear shape of 0.3 mm or more and 1.0 mm or less. The toner supply roller according to claim 1, wherein an angle formed by the longitudinal direction and the spiral shape is 0.5 ° or more and 5.0 ° or less. The toner supply roller according to claim 1, wherein the gear-shaped tooth tip has a round shape with a radius of 0.1 mm or more. The toner supply roller according to claim 3, wherein the tooth tip has a round shape with a radius of 0.3 mm or more. The gear shape, 0.1 mm or more 0.5mm or less of the tip width, 0.05 mm or more 0.5mm or less of the tooth base width, and from the claims 1 having the 1.0mm less tooth height than 0.05 mm 4 The toner supply roller according to claim 1. The gear shape has a tooth tip width represented by X and a tooth root width represented by Y.

Toner supply roller according to one of claims 1 to 5, is satisfied. Toner supply roller of any one of claims 1 to 6, wherein the foamed elastic layer composed of polyurethane foam. The foamed elastic layer has a hardness of 100 g / mm to 750 g / mm,
On the surface of the foamed elastic layer, there are open cells having an opening diameter of 100 μm or more and 800 μm or less, and
The toner supply roller according to claim 7 , wherein the total opening area of the open cell is 20% or more and 90% or less with respect to the surface area of the foamed elastic layer.

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