JP5074647B2 - Toner carrier and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner carrier and an image forming apparatus. More specifically, in an image forming apparatus such as a copying machine or a printer, toner is supplied to an image forming body such as a photoreceptor or paper holding an electrostatic latent image. A toner carrier for forming a visible image on the surface of the image-forming body, giving a high-quality image without image unevenness, and having a small change in characteristics in long-term use and excellent durability. And an image forming apparatus equipped with the same.
[0002]
[Prior art]
Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, a one-component toner is supplied to an image forming body such as a photoreceptor holding an electrostatic latent image, and the toner is attached to the latent image for visualization. As an image forming method, a pressure development method is known (US Pat. Nos. 3,151,2012, 3,731,146, etc.).
In this pressure development method, a toner carrier carrying a toner is brought into contact with an image forming body (photoreceptor) holding an electrostatic latent image, and the toner is adhered to the latent image of the image forming body. For image formation, it is necessary to form the toner carrier with a conductive elastic body having conductivity and elasticity.
That is, in this pressure development method, for example, as shown in FIG. 2, a toner is applied between a toner application roller 5 for supplying toner and an image forming body (photoconductor) 6 holding an electrostatic latent image. A carrier (developing roller) 1 is disposed, and the toner carrier 1, image forming body 6 and toner application roller 5 rotate in the direction of the arrow in the center of the figure, whereby the toner 7 is transferred to the toner by the toner application roller 5. The toner is supplied to the surface of the carrier 1, and the toner is adjusted to a uniform thin film by the layered blade 8. In this state, the toner carrier 1 rotates while being in contact with the image forming body 6, whereby the toner formed in a thin layer adheres from the toner carrier 1 to the latent image of the image forming body 6, and The image is made visible. In the figure, reference numeral 9 denotes a transfer unit, which transfers a toner image to a recording medium such as paper. Reference numeral 10 denotes a cleaning unit which removes toner remaining on the surface of the image forming body 6 after transfer by the cleaning blade 11.
[0003]
In such an image forming apparatus based on the pressure development method, the toner carrier 1 must be rotated while being kept in close contact with the image forming body 6, and as shown in the schematic cross-sectional view of FIG. 1. In addition, elastic rubber or foam such as silicone rubber, NBR (acrylonitrile-butadiene polymer rubber), EPDM (ethylene-propylene-diene copolymer rubber), polyurethane rubber, etc. on the outer periphery of the shaft 2 made of a highly conductive material such as metal. It has a structure in which a conductive elastic layer 3 made of a conductive elastic body provided with conductivity by blending a conductive agent is formed. Further, the toner 7 is made of a resin or the like for chargeability and adhesion to the toner 7, for controlling the frictional force between the image forming body 6 and the layered blade 8, or for preventing the image forming body from being contaminated by an elastic body. A covering layer 4 is provided on the surface of the conductive elastic layer 3.
On the other hand, an image forming method is also proposed in which an image is formed by directly flying toner carried on a toner carrying body through a hole-like control electrode on an image forming body made of paper such as paper or OHP paper. Has been. Further, a non-magnetic toner layered in a thin layer is carried on the surface of a sleeve-like toner carrier disposed in a non-contact state in the vicinity of the image forming body (photosensitive body), and this is carried on the image forming body. There has also been proposed a method of developing by flying and forming an image (Japanese Patent Laid-Open No. 58-116559).
[0004]
In any case, on the toner carrying member, for the purpose of controlling the chargeability and adhesion to the toner, or for reducing the frictional force with other members such as the image forming member, the layered blade, and the control electrode, A coating layer made of resin or the like is provided on the surface of the conductive elastic layer.
The present inventors have so far proposed a toner carrier using a resin such as melamine resin, phenol resin, alkyd resin, fluororesin, polyamide resin, etc. as a toner carrier that can improve friction and images. I have done it.
[0005]
[Problems to be solved by the invention]
However, recently, as printers and the like have been speeded up, fine images are required, or color images have been made, the demand for image formation has become severe, and various problems that cannot be dealt with by conventional toner carriers. Has become apparent.
As one of them, there is an influence of excessive stress on the members generated as a result of driving various members at a high speed in order to improve the printing speed. That is, when a toner carrier is incorporated in a printer or the like and high-speed printing is performed continuously for a long time, streaky scratches may occur on the surface of the carrier.
[0006]
As a result of studying the above problems, the present inventors have found that the phenomenon is caused by the following causes.
That is, in the image forming apparatus as shown in FIG. 2 as an example, when the residual toner remaining on the surface of the photosensitive member 6 and the toner carrier has a very large mirror image force, or the tackiness of the surface layer of the toner carrier When the toner is large, residual toner may not be completely removed by the cleaning blade 11 or the toner application roller 5. When continuous printing is continued for a long time in this state, the adhered residual toner is gradually fused by friction between the layered blade 8 and the photoreceptor 6 and the toner carrier 1, and a toner fixed body is formed on the layered blade 8. Each time the toner carrying member is rubbed, the toner carrying member applies a local stress. If such a state continues for a while, the surface of the toner carrying member may be damaged. Since this phenomenon is strongly influenced by the mirror image force, it is particularly likely to occur in a system in which toner is highly charged in printer design. Since this scratch is also reflected in the printed image, preventing it from occurring is an indispensable issue for realizing a high-speed printer.
The present invention has been made in view of such circumstances, and a toner carrier that can be suitably applied to a high-speed printing printer that can withstand long-term continuous printing even in a printer design using highly charged toner. And an image forming apparatus using the toner carrier.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors first focused on the following.
(1) To increase the toner cleaning efficiency and suppress the adhesion of residual toner.
(A) In order not to increase the mirror image power of the toner, the toner carrier is treated with a low chargeability coating film.
(B) The surface of the toner carrying member is treated with a low tack coating film.
(2) A carrier surface that is resistant to scratches caused by toner adherents is formed.
(C) The toner carrier is treated with a high-strength coating film.
Among these, for (b), since the coating material for coating layers currently generally prescribed has already achieved sufficiently low tackiness, further improvement is difficult, and extreme friction reduction is not possible. Since this also leads to the deterioration of the toner transportability of the toner carrier, it is necessary to solve the problem with this method in view of the overall design of the printer, and it is difficult to say that it is effective in all systems. In addition, (a) is compatible with the design of a highly charged toner system, and (c) is likely to crack the coating layer due to the effect of curing as the strength increases. It's not easy.
[0008]
As a result of further research, the present inventors have found that the above object can be achieved by incorporating the effects (a) and (c) in a balanced manner. That is, it succeeded in achieving the said subject by using the methyl ether modified melamine compound as a hardening | curing agent for the thermosetting resin used as a coating layer.
When a melamine resin is used as a constituent resin component of the coating layer, excellent chargeability can be imparted to the toner carrier, but in general such a system tends to form a hard and brittle coating layer. This is presumably due to the formation of a melamine skeleton cluster structure by self-condensation of the melamine resin. On the other hand, in the case of a resin using a methyl ether-modified melamine compound as a curing agent, a melamine self-condensation hardly occurs and a coating layer with a small brittleness can be formed. In particular, it has been found that the above-mentioned effect appears remarkably when a fully-alkylated mononuclear structure is used. This fact is advantageous for increasing the strength of the toner carrier coating layer.
[0009]
It was also found that when the coating layer having this structure is provided, the charging ability is lower than that of a system using a general melamine resin. The reason for this is not speculative, but is estimated as follows. In other words, the structure of melamine resin is advantageous in terms of electron donating performance, and exhibits excellent electron emission capability. However, in this configuration, the number of melamine clusters is reduced, so that the electron donating capability of melamine is reduced. It is thought that it was suppressed to some extent. This fact works favorably for making the toner carrier moderately low in charging ability and suppressing the mirror image force of the residual toner.
The present invention has been completed based on such findings.
[0010]
That is, the present invention forms a thin film by supporting a toner on the surface, and in this state, contacts or approaches the image forming body to supply the toner to the surface of the image forming body, In the toner carrier for forming a visible image on the surface, the toner carrier comprises a thermosetting resin cured with a methyl ether-modified melamine compound on the surface of the conductive elastic layer, and the thermosetting resin and the methyl ether modified The present invention provides a toner carrier characterized by having a coating layer made of a material having a melamine compound usage ratio of 50:50 to 98: 2 by weight.
[0011]
According to the present invention, a toner carrier is mounted, and a toner is carried on the surface of the toner carrier to form a thin film. The toner carrier is brought into contact with or close to the image forming body to form the image. An image forming apparatus for forming a visible image on a surface of an image forming body by supplying toner to the surface of the body, wherein the toner supporting body of the present invention is used as the toner supporting body. Is also provided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the toner carrier of the present invention has a conductive elastic layer 3 formed on the outer periphery of a highly conductive shaft 2 and a coating layer 4 formed on the surface of the conductive elastic layer 3. Any shaft can be used as long as it has good electrical conductivity. Usually, a metal such as a metal core made of a solid metal or a hollow metal hollow body is used. A shaft made of steel is used.
For the conductive elastic layer 3, an elastic material obtained by adding a conductive agent to an appropriate rubber material to provide conductivity is used. Here, the rubber material is not particularly limited, and for example, nitrile rubber, ethylene propylene rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, silicone rubber, urethane rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber. These may be used singly or may be used in combination of two or more, but among these, in particular one or two selected from chloroprene rubber, butadiene rubber, ethylene propylene rubber and urethane rubber A mixture of the above is preferred.
[0013]
On the other hand, the conductive agent added to these rubber materials includes an ionic conductive agent and an electronic conductive agent. Examples of the former ionic conductive agent include dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium, and lauryltrimethylammonium. Perchlorate such as hexadecyltrimethylammonium, stearyltrimethylammonium, benzyltrimethylammonium, modified aliphatic dimethylethylammonium, chlorate, hydrochloride, bromate, iodate, borofluoride Ammonium salts such as acid salts, sulfates, alkyl sulfates, carboxylates and sulfonates; perchlorates, chlorates and hydrochlorides of alkali metals or alkaline earth metals such as lithium, sodium, calcium and magnesium , Periodate, iodate, fluoroboric acid salts, trifluoromethyl sulfate, and sulfonic acid salts.
Examples of electronic conductive agents include conductive carbon blacks such as ketjen black and acetylene black; carbon blacks for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT; Examples thereof include carbon black for ink, pyrolytic carbon black, graphite; conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; powders such as metals such as nickel and copper.
[0014]
These conductive agents may be used alone or in combination of two or more. Further, the amount of addition is not particularly limited, but in the case of an ionic conductive agent, it is in the range of 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the rubber material. In the case of an electronic conductive agent, it can be in the range of 1 to 50 parts by weight, preferably 5 to 40 parts by weight.
By adjusting the addition amount of the conductive agent, the resistance value of the conductive elastic layer is reduced to 10^Three-10^TenΩ · cm, especially 10^Four-10⁸It is preferable to adjust to the range of Ω · cm. In addition to the conductive agent described above, other rubber additives such as conventionally known fillers and crosslinking agents can be appropriately added to the conductive elastic layer as necessary.
The hardness of the conductive elastic layer is preferably 60 ° or less, particularly 25 to 55 ° in JIS-A. If the hardness exceeds 60 °, the toner carrier becomes hard, the contact area with the photosensitive member or the like becomes small, and there is a risk that good image formation cannot be performed. Toner sticking to the blade occurs, causing image defects. On the other hand, if the hardness is too low, friction with the image forming body and the stratified blade increases, which may cause image defects such as jitter.
[0015]
Since the conductive elastic layer is used in contact with an image forming body or a layered blade, it is preferable that the compression set is small, specifically 20% or less, particularly 10% or less. In particular, polyurethane rubber is preferable because the compression set can be designed to be small.
The surface roughness of the conductive elastic layer is JIS 10-point average roughness, preferably 15 μm Rz or less, particularly preferably 3 to 10 μm Rz. When this average roughness exceeds 15 μm Rz, it is necessary to form a thick coating layer that forms the surface of the toner carrier, and as a result, the surface of the toner carrier becomes hard and damages the toner. This is not preferable because the toner adheres to the toner and causes an image defect. On the other hand, if Rz is too small, when the coating layer is formed, Rz on the surface of the toner carrying member becomes too small, and the toner carrying amount is reduced, which may reduce the image density.
[0016]
The surface roughness was measured using a surface roughness meter “Surfcom 590A” (manufactured by Tokyo Seimitsu Co., Ltd.) in the circumferential direction with a measurement length of 2.4 mm, a measurement speed of 0.3 mm / second, and a cutoff wavelength of 0. It is a value obtained by measuring 300 points or more so that there is no deviation in the shaft direction and circumferential direction of the roller at .8 mm (the same applies hereinafter).
In the toner carrier of the present invention, for controlling the chargeability and adhesion to the toner, for reducing the frictional force with the image forming body and the stratified blade, or for preventing the image forming body from being contaminated by the elastic body. Therefore, a coating layer made of resin or the like is provided on the surface of the conductive elastic layer.
[0017]
In this invention, this coating layer is comprised from the material containing the thermosetting resin formed by hardening with a methyl ether modified melamine compound. When the thermosetting resin is cured with a methyl ether-modified melamine compound, an acidic catalyst can be used as desired in order to shorten reaction completion and heat treatment time.
Examples of the thermosetting resin include modified alkyd resins, oil-free alkyd resins, and alkyd-modified, epoxy-modified or alcohol-modified resins (specifically, alkyd-modified urethane resins, alkyd-modified silicone resins, epoxy-modified silicone resins, alcohols). At least one selected from modified silicone resins and the like is preferably used. Among these thermosetting resins, oil-free alkyd resins, alkyd-modified silicone resins, epoxy-modified silicone resins, and alcohol-modified silicone resins are more preferable, and oil-free alkyd resins are particularly preferable.
[0018]
On the other hand, examples of methyl ether-modified melamine compounds used as curing agents include fully alkylated methyl ether-modified melamine, methylol group-type methyl ether-modified melamine, imino group-type methyl ether-modified melamine, and intermediates thereof. Among them, the fully alkylated methyl ether-modified melamine, the imino group-type methyl ether-modified melamine, and the intermediate type are more preferable, and the fully alkylated methyl ether-modified melamine and the completely An intermediate type between an alkylated methyl ether-modified melamine and an imino group-type methyl ether-modified melamine is preferred. One of these methyl ether-modified melamine compounds may be used alone, or two or more thereof may be used in combination.
In addition, as the acidic catalyst used as desired, when a fully alkylated methyl ether-modified melamine is used as a curing agent, a strong acidic aromatic sulfonic acid catalyst is preferably used, and other curing agents are weak. An acidic phosphate ester catalyst is preferably used. The aromatic sulfonic acid catalyst may be an amine block type.
[0019]
In the present invention, the use ratio of the thermosetting resin and the methyl ether-modified melamine compound is selected in the range of 50:50 to 98: 2 by weight from the physical properties of the coating layer.
The coating layer according to the present invention preferably has an insoluble portion of 70% by weight or more with respect to the solvent. When the insoluble portion is less than 70% by weight, the coating layer and the toner carrier such as an image forming body or a stratified blade can be left standing for a long time. There is a possibility that pressure contact traces of the contacted member are formed, and as a result, a defect such as a black horizontal line may occur in the image. In particular, the solvent-insoluble part is preferably 80% by weight or more.
[0020]
The coating layer according to the present invention is mainly composed of a thermosetting resin cured by the above-described curing agent. In addition to this, the toner is further improved in charging ability, reduced in frictional force with other members, For the purpose of imparting conductivity, various additives such as a charge control agent, a lubricant, a conductive agent, and other resins can be contained.
In the toner carrier of the present invention, it is preferable for adjusting the resistance of the toner carrier that the resistance of the coating layer is higher than the resistance of the conductive elastic layer. 10⁹-10¹⁵Ω · cm, especially 10^Ten-10¹³A range of Ω · cm is preferred. The resistance of the toner carrier is 10⁶-10¹²The range of Ω · cm is preferable.⁷-10^TenΩ · cm is particularly preferable.
[0021]
Further, the surface roughness of the toner carrier on which the coating layer is formed is preferably 10 μmRz or less, particularly 1 to 8 μmRz in terms of JIS 10-point average roughness. If this average roughness exceeds 10 μm Rz, the toner charge amount becomes small, or reversely charged toner is generated, which is not preferable. On the other hand, if Rz is too small, the toner carrying amount decreases, and the image density may be lowered.
The method for forming the coating layer in the toner carrier of the present invention is not particularly limited, but the thermosetting resin, the methyl ether-modified melamine compound and the acidic catalyst and various additives used as necessary are dissolved or dispersed. After the coating liquid is applied on the conductive elastic layer by a dipping method, a roll coater method, a doctor blade method, a spray method, etc., it is dried and crosslinked and cured at a temperature of about 50 to 170 ° C.
[0022]
Although the thickness of this coating layer can be about 3-50 micrometers, the range of 5-30 micrometers is especially preferable. If the coating layer is too thin, local discharge occurs and white horizontal lines are likely to occur in the image. On the other hand, if the thickness is too thick, the toner carrier becomes hard and damages the toner, causing the toner to adhere to the image forming body and the stratified blade, causing image defects.
Examples of the solvent used for the preparation of the coating liquid include alcohol solvents such as methanol, ethanol, isopropanol and butanol, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbon solvents such as toluene and xylene, Aliphatic hydrocarbon solvents such as hexane, alicyclic hydrocarbon solvents such as cyclohexane, ester solvents such as ethyl acetate, ether solvents such as isopropyl ether and tetrahydrofuran, amide solvents such as dimethylformamide, chloroform and dichloroethane And halogenated hydrocarbon solvents such as these, and mixed solvents thereof. In the present invention, alcohol solvents and mixed solvents of alcohol solvents and various hydrocarbon solvents are particularly preferably used.
[0023]
The toner carrier of the present invention is used as a developing roller or the like incorporated in an image forming apparatus such as a developing apparatus in an electrophotographic apparatus. For example, as shown in FIG. 2, toner for supplying toner is used. The toner carrier of the present invention is disposed as the developing roller 1 between the coating roller 5 and the photosensitive drum (image forming body) 6 holding the electrostatic latent image, and the toner 7 is carried by the toner coating roller 5. Then, this is formed into a uniform thin layer by the stratified blade 8, and toner is supplied from the thin layer to the photosensitive drum (image forming body) 6, and the toner adheres to the electrostatic latent image on the photosensitive drum (image forming body) 6. To visualize the latent image. Since the details of the image forming apparatus shown in FIG.
[0024]
The image forming apparatus to which the toner carrier of the present invention is attached is not limited to the one shown in FIG. 2, and a toner is carried on the surface to form a thin layer of the toner. Any one may be used as long as it forms a visible image on the surface of the image forming body by supplying toner to the surface of the image forming body in contact or proximity. For example, a paper sheet such as paper or OHP paper is used as an image forming body, and the toner carried on the toner carrying body is made to fly directly through a hole formed in the control electrode, so that the image is directly applied to the paper or OHP paper. It may be formed.
Further, as the toner carried on the toner carrier of the present invention, a non-magnetic one-component developer is preferably used, but a magnetic type one-component developer can also be used, for example, a magnetic one-component developer is used. Thus, the toner carrier and the image forming apparatus of the present invention can also be suitably used when performing monochrome image printing.
[0025]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the characteristic test was done in the following way about the roller (toner carrier) obtained by the Example and the comparative example.
(1) Layer thickness of the coating layer
The vertical cut surface of the roller to be tested was observed and measured with a scanning electron microscope.
(2) Solvent insolubility of the coating layer
Separately from the roller to be tested, prepare a glass plate, apply the coating solution used to form the coating layer of each roller to the glass plate, and heat and cure the coating film under the same conditions as the production of each roller. A coating film sample was prepared. This glass plate was immersed in a solvent similar to that used for the preparation of the coating solution at room temperature for 24 hours, and then dried, and the weight of the coating film before and after immersion was measured. Was calculated as the solvent insolubility of the coating layer of the roller, and it was confirmed whether the solvent insolubility of the coating layer was 70% by weight or more.
Solvent insolubility = [(weight of coating after immersion in solvent, drying) / (weight of coating before immersion in solvent)] × 100 (% by weight)
(3) Roller resistance
A load of 500 g was applied to both ends of the roller under test and pressed onto the copper plate, and a resistance value was measured by applying a voltage of 100 V using a resistivity meter R8340A (manufactured by Advantest).
(4) Toner charge amount
The test roller is used as a developing roller and is mounted on the developing unit shown in FIG. 2, and the developing roller is rotated at a peripheral speed of 50 mm / second to form a thin toner layer on the surface of the developing roller. Aspiration was introduced into the Faraday gauge, and the amount of charge was measured. At the same time, the amount of sucked toner was also measured to determine the toner charge amount [q / m (μC / g)] per unit weight.
[0026]
referenceExample 1
  Propylene oxide and ethylene oxide are added to glycerin to obtain a molecular weight of 5,000. Polyether polyol (OH value: 33) 100 parts (parts by weight, the same applies hereinafter) 1,4-butanediol 1.0 parts, nickel acetylacetonate 0 0.5 parts, 0.01 parts of dibutyltin dilaurate and 2.0 parts of acetylene black were added and mixed using a mixer to prepare a polyol composition.
  The polyol composition was stirred under vacuum to degas, then 17.5 parts of urethane-modified MDI was added and stirred for 2 minutes, and this was poured into a mold that had been placed at a metal shaft and heated in advance to 110 ° C. Then, it was cured at 110 ° C. for 2 hours to form a conductive elastic layer on the outer periphery of the metal shaft to obtain a roller. The surface of the obtained roller was polished, and the surface was adjusted to a JIS 10-point average roughness of 15.0 μm Rz.
[0027]
The surface roughness was measured using a surface roughness meter “Surfcom 590A” (manufactured by Tokyo Seimitsu Co., Ltd.) in the circumferential direction with a measurement length of 2.4 mm, a measurement speed of 0.3 mm / second, and a cutoff wavelength of 0. It is a value obtained by measuring 300 points or more so that there is no deviation in the shaft direction and circumferential direction of the roller at .8 mm (the same applies to the following examples).
Next, by adding acetylene black as a conductive agent to the polyether polyurethane resin solution, the volume resistivity during film formation is 1.08 × 10⁸A coating solution having a solid concentration of 12.5% by weight adjusted to Ω · cm was prepared. The conductive elastic roller was dipped in the coating solution and pulled up and air-dried at 100 ° C. for 30 minutes.
Furthermore, oil-free alkyd resin [Dainippon Ink Co., Ltd., trade name: Beckolite M-6402-50, solid content 50% by weight] and methyl ether-modified melamine [Mitsui Cytec Co., Ltd., trade name: Cymel 325 , 80 wt% solid content] was blended to a solid content weight ratio of 70:30, and then diluted with methyl ethyl ketone to prepare a coating solution for coating with a solid content concentration of 15 wt%. The air-dried conductive elastic roller was returned to room temperature, then dipped in the coating solution, pulled up, heated to 110 ° C. and cured for 4 hours, and the roller-shaped toner carrier shown in FIG. 1 was obtained.
[0028]
Using the toner carrier as a phenomenon roller, in the developing unit shown in FIG. 2, a negatively chargeable nonmagnetic one-component toner having a developing bias of −400 V and a blade bias of −600 V and an average particle diameter of 7 μm is used, and the linear velocity is 60 mm / sec. An image was obtained by reversal development while rotating at a peripheral speed, and image evaluation was performed on white, halftone, and black images. A total of 5 images were evaluated for both the initial image and the durable image, and the tendency was grasped. As the durable image, a printed image after 10,000 sheets of continuous 4% printing was used (printing conditions and evaluation methods are the same in the following examples). Further, when the toner charge amount (q / m) in the phenomenon system was measured before the endurance test, it showed a slightly higher chargeability characteristic of 43.70 μC / g.
[0029]
  As a result of the above test, good printing results could be obtained for both initial and durable images. In particular, after the endurance test, the surface of the toner carrying member was observed with a video microscope. As a result, no scratches were observed and the image was kept in a good state.
referenceExample 2
  referenceIn Example 1, except that the solid content weight ratio of the oil-free alkyd resin and the methyl ether-modified melamine was 95: 5,referenceA roller-shaped toner carrier was prepared in the same manner as in Example 1.
  Using the toner carrier as a developing roller,referenceThe same test as in Example 1 was performed. Further, when the toner charge amount (q / m) in the development system was measured before the endurance test, it showed a medium chargeability characteristic of 38.55 μC / g.
[0030]
  As a result of the above test, good printing results could be obtained for both initial and durable images. In particular, after the endurance test, the surface of the toner carrying member was observed with a video microscope. As a result, no scratches were observed and the image was kept in a good state.
Example1
  referenceIn Example 1, instead of methyl ether-modified melamine, a fully alkylated mononuclear methyl ether-modified melamine [manufactured by Mitsui Cytec Co., Ltd., trade name: Cymel 303, solid content: 100%] was used, and the coating liquid for coating was used. Except for adding 0.15% by weight of an aromatic sulfonic acid-based catalyst [Mitsui Cytec Co., Ltd., trade name: KYATALIST 4040, main component 40% by weight] based on the weight of the coating solution,referenceA roller-shaped toner carrier was prepared in the same manner as in Example 1.
[0031]
  Using the toner carrier as a developing roller,referenceThe same test as in Example 1 was performed. Further, when the toner charge amount (q / m) in the developing system was measured before the durability test, it showed a slightly higher chargeability characteristic of 46.45 μC / g.
  As a result of the above test, good printing results could be obtained for both initial and durable images. In particular, after the endurance test, the surface of the toner carrying member was observed with a video microscope. As a result, no scratches were observed and the image was kept in a good state.
Comparative Example 1
  referenceIn Example 1, instead of methyl ether-modified melamine, n-butyl ether-modified melamine (Dainippon Ink Co., Ltd., trade name: Super Becamine L-117-60, solid content 60% by weight) was used.referenceA roller-shaped toner carrier was prepared in the same manner as in Example 1.
  Using the toner carrier as a developing roller,referenceThe same test as in Example 1 was performed. Further, when the toner charge amount (q / m) in the developing system was measured before the durability test, it showed a high chargeability characteristic of 59.79 μC / g.
[0032]
  As a result of the above test, good results were obtained for the initial image. After the durability test, the toner carrier was observed with a video microscope. As a result, many scratches having a length of 1 to 2 mm were generated on the surface. It also appeared in the image and appeared as a spot on the halftone image / solid black image.
Comparative Example 2
  referenceIn Example 1, except that the solid content weight ratio of the oil-free alkyd resin and methyl ether-modified melamine was 30:70,referenceA roller-shaped toner carrier was prepared in the same manner as in Example 1.
  Using the toner carrier as a developing roller,referenceThe same test as in Example 1 was performed. Further, when the toner charge amount (q / m) in the developing system was measured before the durability test, it showed a remarkably high chargeability characteristic of 71.35 μC / g. As a result of the above test, the initial image has an image characteristic in which the density is slightly increased centering on the halftone image. After the endurance test, the surface of the toner carrier was observed with a video microscope. As a result, many scratches having a length of 1 to 2 mm were generated on the surface, which appeared in the image and appeared as spots in the halftone image. .
[0033]
Comparative Example 3
  referenceIn Example 1, instead of using an oil-free alkyd resin and methyl ether-modified melamine as a coating liquid for coating, phenol resin [manufactured by Sumitomo Durez Co., Ltd., trade name: Sumilite Resin PR-50232, solid content 50 wt% Except that the coating liquid prepared with a solid content concentration of 12% by weight was used.referenceA roller-shaped toner carrier was prepared in the same manner as in Example 1.
  Using the toner carrier as a developing roller,referenceThe same test as in Example 1 was performed. Further, when the toner charge amount (q / m) in the development system was measured before the durability test, it showed a remarkably high chargeability characteristic of 69.71 μC / g. As a result of the above test, the initial image has an image characteristic in which the density is slightly increased centering on the halftone image. After the endurance test, the surface of the toner carrying member was observed with a video microscope. As a result, many scratches with a length of 1 to 2 mm were generated on the surface, which appeared in the image and became spots on the halftone image / solid black image. Appeared.
[0034]
【The invention's effect】
According to the present invention, it is possible to obtain a toner carrier that can be suitably applied to a high-speed printer capable of withstanding long-term continuous printing even in a printer design using highly charged toner.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of a toner carrier of the present invention.
FIG. 2 is a schematic cross-sectional view showing an example of an image forming apparatus of the present invention.
[Explanation of symbols]
1: Toner carrier (developing roller)
2: Shaft
3: Conductive elastic layer
4: Coating layer
5: Roller for toner application
6: Image forming body (photoreceptor)
7: Toner
8: Stratified blade
9: Transfer section
10: Cleaning section
11: Cleaning blade

Claims (8)

A toner is carried on the surface to form a thin film, and in this state, a visible image is formed on the surface of the image forming body by supplying the toner to the surface of the image forming body by contacting or approaching the image forming body. In the toner carrier,
The toner carrier includes a thermosetting resin cured with a methyl ether-modified melamine compound using an acidic catalyst on the surface of the conductive elastic layer, and a use ratio of the thermosetting resin and the methyl ether-modified melamine compound is A toner carrier comprising a coating layer made of a material having a weight ratio of 50:50 to 98: 2.   2. The toner carrier according to claim 1, wherein the methyl ether-modified melamine compound is a fully alkylated methyl ether-modified melamine, a methylol group-type methyl ether-modified melamine, an imino group-type methyl ether-modified melamine, or an intermediate type thereof. Thermosetting resin, modified alkyd resins, oil-free alkyd resin and an alkyd-modified, epoxy-modified or toner carrying member according to claim 1 or 2 is at least one selected from among alcohol-modified resin. The toner carrier according to any one of claims 1 to 3 , wherein the rubber elastic body constituting the conductive elastic layer is at least one selected from chloroprene rubber, butadiene rubber, ethylene propylene rubber and urethane rubber. Toner carrier according to any one of claims 1-4 insoluble rate in the solvent of the coating layer is 70 wt% or more. Toner carrier according to any one of claims 1 to 5 the thickness of the coating layer is 3 to 50 [mu] m. Toner carrier according to any one of claims 1 to 6 surface roughness is 10μmRz less in average roughness JIS10 points. A toner carrier is mounted, and a toner is carried on the surface of the toner carrier to form a thin film thereof. The toner carrier is brought into contact with or close to the image forming body, and the toner is applied to the surface of the image forming body. In an image forming apparatus for forming a visible image on the surface of the image forming body by supplying, the toner carrying body according to any one of claims 1 to 7 is used as the toner carrying body. apparatus.

Images