JP2011138109A - Image forming device and process cartridge used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a less expensive image forming device keeping high-quality outputs for a long period. <P>SOLUTION: The image forming device 10 is equipped with: photoreceptors 1; charging means 3 that charge the photoreceptors; a latent image forming means L that forms respective latent images on the surface of the charged photoreceptors; developing means 5 that develop the respective latent images formed on the surface of the photoreceptors into respective toner images by using a developer containing a toner; transfer means 6 that transfer the respective toner images formed on the surface of the photoreceptors onto an transfer object; and cleaning meas 4 that remove residual toner on the photoreceptor surface after transfer. The photoreceptor has BN adhering onto the surface by removing a protection sheet after being covered with the protection sheet having BN adhering onto the photoreceptor side surface, and the photoreceptors having BN adhering onto the surface are mounted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using a protective agent for protecting a photoreceptor and a cleaning blade from mechanical stresses such as frictional force in image forming apparatuses such as copying machines, printers, and facsimiles.

  In an image forming apparatus using an electrophotographic process, image formation is performed by subjecting a photoreceptor to a charging step, an exposure step, a development step, and a transfer step. The discharge product generated in the charging process and remaining on the surface of the photoreceptor and the residual toner or toner component remaining on the surface of the photoreceptor after the transfer process are removed through a cleaning process.

  As a generally used cleaning method, a rubber blade that is inexpensive, has a simple mechanism, and has excellent cleaning properties is used. However, since the rubber blade is pressed against the photoconductor to remove the residue on the surface of the photoconductor, stress due to friction between the photoconductor surface and the cleaning blade is large. Wear, shortening the life of rubber blades and organophotoreceptors. In addition, the toner used for image formation in response to the demand for higher image quality has become a small particle size. In an image forming apparatus using small-diameter toner, the rate at which residual toner passes through the cleaning blade increases. In particular, the dimensional accuracy and assembly accuracy of the cleaning blade are insufficient, or the cleaning blade partially vibrates. In such a case, the toner slips through the image and prevents high-quality image formation.

  In response to this requirement, a method in which a brush is pressed against a lubricant (protective agent) and rotated to supply the protective agent to powder on the photoreceptor, and a lubricant film is formed with a cleaning blade, etc. Is adopted. Since the cleaning blade and the surface of the photoconductor are protected by the lubricant by interposing the lubricant between the photoconductor and the cleaning blade, the photoconductor wear caused by friction between the cleaning blade and the photoconductor, the deterioration of the cleaning blade, the photoconductor Deterioration of the photoreceptor due to the energy of discharge generated when charging is reduced. In addition, since the lubricity of the surface of the photoreceptor is increased by applying the lubricant, the phenomenon that the cleaning blade partially oscillates is reduced, and the amount of slip-through toner is reduced. However, since the lubricant is supplied to the rotating photoconductor during image formation, the lubricant is not applied before film formation unless the lubricant is applied to the photoconductor in advance. The photoconductor was not coated with a lubricant, and the lubricity between the photoconductor and the cleaning blade was poor at the initial stage of image formation, causing deterioration of the blade and the photoconductor.

  In recent years, color machines have become the mainstream of image forming apparatuses, and high-quality images are desired. Therefore, the charging method uses AC charging in which a charging roller is used as a charger and an AC voltage is superimposed on a DC voltage. The method has become mainstream. In addition, the AC charging method using a charging roller can meet the needs for downsizing, and the generation amount of oxidizing gases such as ozone and NOx is small, so the needs are high. However, in the case of the DC charging method, the photosensitive member is charged by only one positive discharge while passing through the charger, but in the case of using the AC charging method, several hundreds per second depending on the frequency. Since the photosensitive member is charged by repeating positive and negative discharges of several thousand times, the hazard received by the photosensitive member is very large compared to the DC charging method, and the function of protecting the photosensitive member is becoming more important.

In this way, the need to apply a large amount of a protective agent and the need to clean small-diameter toner has increased the movement to improve the cleaning effect of the cleaning blade, which accelerates the deterioration of the cleaning blade. Tended to end up.
In addition, when the pressure to press the brush against the protective agent is increased to apply a large amount of the protective agent, and the protective agent becomes large particles and is supplied to the photoconductor, the blade is easily slipped through and the protective agent is exposed to light. There was a problem that it was difficult to coat the body uniformly.

Further, since the lubricant such as toner or metal soap that has passed through the blades is scattered and fixed on the charging roller to cause poor charging, it has been a problem to prevent the charging roller from being contaminated.
On the other hand, in the past, the life of only the photoconductor was extended, and the charging roller and the cleaning blade had a tendency to be replaced when they deteriorated.However, in consideration of the environment, all members such as the charging roller, the cleaning blade, the photoconductor, Since there is an increasing need for a long life, a technology for preventing deterioration and contamination of each member is required.

  When using metal soap, the problem is that the metal soap powder supplied to the photoconductor passes through the blade in the state of powder, scatters on the charging roller, adheres, and causes poor charging. In order to reduce this, a protective agent in which boron nitride (BN) is blended with metal soap has been studied as a protective agent for a photoreceptor that is replaced with metal soap (Patent Document 1). According to Patent Document 1, by adding boron nitride (BN) to metal soap (zinc stearate), metal soap powder scattering and blade wear on the charging roller can be reduced over a long period of time. It has been reported that mixing boron nitride (BN) inorganic lubricants with metal soaps has proved effective. In addition, this lubricant can be used by replacing the conventionally used zinc stearate bar. However, since BN is very expensive, the cost related to the lubricant has been considerably higher than the conventional one, instead of being highly effective when supplied to the photoreceptor.

  SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an image forming apparatus that can maintain a high-quality output for a long time at a lower cost. Particularly, it is an object of the present invention to provide an image forming apparatus that significantly extends the life of a photoconductor, a charging roller, a cleaning blade, and a protective agent coating blade, and that requires less frequent replacement of each member or process cartridge.

  The present inventors have a system for extending the lifetime of all members for the purpose of extending the lifetime of all members around the photoreceptor such as a cleaning blade, a charging roller, and an intermediate transfer belt as well as the lifetime of the photoreceptor. In order to realize this, we have intensively studied how to do it. First, the inventors believe that lowering the frictional force between the cleaning blade and the photoconductor will lead to longer life of both the cleaning blade and the photoconductor. investigated.

  A method of applying metal soap is widely known as a method of reducing the frictional force, but metal soap contributes to extending the life of the photoconductor, but in order to reduce the frictional force, more and more metal soap is applied. As a result, the deteriorated metal soap accelerates the deterioration of the cleaning blade. Therefore, it has not been possible to find a method for extending the life of both the photoconductor and the cleaning blade with the metal soap alone. Therefore, instead of metal soap, an investigation was made as to whether there is a lubricant that reduces friction between the cleaning blade and the photoreceptor. I tried a method of passing a lubricant such as silicone resin, acrylic resin, ethylene acrylic resin, fluorine resin between the cleaning blade and the photoconductor. The effect of suppressing the deformation was low, and the blades deteriorated due to the occurrence of minute vibrations, and the life of the blades was not dramatically extended. Further, when the blade vibrates finely, the lubricant itself slips through, or the toner slips through, and the slipped material is scattered on the charging roller, leading to charging failure. However, when a large amount of image formation was performed by attaching a lubricant containing BN mixed with metal soap to the photoreceptor, the life of the blade was dramatically increased, and the toner and lubricant from the blade were prevented from slipping through. The phenomenon of charging failure due to charging roller contamination is no longer observed. From this, it has been found that a system for supplying a mixture of metal soap and BN to the photoconductor can realize a long life of all the members of the photoconductor, blade, and charging roller, but BN is an expensive substance. Therefore, further investigation was made to determine whether each member could have a longer life at a lower cost.

  As a result, when BN is continuously supplied, the consumption of BN increases. However, BN is hardly fixed on the photoconductor, and most of the BN supplied to the photoconductor is developed together with toner, It was discharged with waste toner. However, a certain amount of BN adheres to the blade, and the attached BN is hardly separated from the blade, and is located between the blade and the photosensitive member, so that the vibration of the blade is suppressed and toner slipping is prevented. It had been.

Therefore, the present inventors can cover the photoconductor by adhering BN powder to the photoconductor side surface of the photoconductor protective sheet. When the photoconductor is started to be used, the photoconductor is protected from the photoconductor protective sheet. The BN powder moves and adheres to the surface, and the BN adhering to the photosensitive member moves between the photosensitive member and the blade when the photosensitive member rotates, and is held between the photosensitive member and the blade for a long time. The BN powder is adhered to the surface of the photosensitive member side of the protective sheet for the photosensitive member to cover the photosensitive member, and after holding for a certain period of time, the protective sheet is removed and assembled to the photosensitive member in the machine. Image output was performed. As a result, the life of the photosensitive member, the blade, and the charging roller has been significantly increased. Further, the BN was hardly fixed on the photoconductor after a large amount of image output was performed, like the photoconductor when BN was constantly supplied. From this, it has been found that BN is only required to adhere BN powder to the photoreceptor side surface of the protective sheet of the photoreceptor, and it is not necessary to constantly supply BN, thus reaching the present invention.
That is, the image forming apparatus and the process cartridge according to the present invention have the following configurations.

(1) a photoconductor;
Charging means for charging the photoreceptor;
Latent image forming means for forming a latent image on the surface of the charged photoreceptor;
Developing means for developing a latent image formed on the surface of the photoreceptor with a developer containing toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the photoreceptor to a transfer target;
An image forming apparatus including a cleaning unit that removes residual toner on the surface of the photoreceptor after transfer,
As the photosensitive member, a photosensitive member having BN attached to the surface obtained by removing the protective sheet after being covered with the protective sheet having BN attached to the surface on the photosensitive member side is mounted. Image forming apparatus.
(2) The image forming apparatus as described in (1) above, wherein the protective sheet for the photosensitive member has a mixture of metal soap and BN attached to the surface on the photosensitive member side.
(3) The mixing ratio of the metal soap and BN adhered to the surface on the photosensitive member side of the protective sheet for the photosensitive member is BN in a weight ratio of 10% or more, as described in (2) above Image forming apparatus.
(4) The image forming apparatus according to any one of (1) to (3), further comprising means for supplying metal soap as a protective agent to the photoconductor.
(5) BN is contained in the protective agent supplied to the photoconductor,
The image forming apparatus as described in (4) above, wherein the blend ratio of the metal soap and BN is a weight ratio, and BN is 30% or less.
(6) The image forming apparatus according to any one of (2) to (5), wherein the metal soap is a mixture of zinc palmitate and zinc stearate.
(7) The image forming apparatus as described in (5) or (6) above, wherein the protective agent supplied to the photoreceptor contains alumina in addition to metal soap and BN.
(8) The image forming apparatus according to any one of (4) to (7), wherein a blade is provided as means for supplying a protective agent separately from the cleaning means.
(9) The image forming apparatus according to (8), wherein BN or a mixture of metal soap and BN is attached to the blade, which is a means for supplying the protective agent, in a state before the start of use.
(10) The image forming apparatus according to (8) or (9), wherein a blade as a means for supplying the protective agent is in contact with the photoconductor at an angle similar to a counter system.
(11) The image forming apparatus as described in any one of (8) to (10) above, wherein the blade as means for supplying the protective agent is an obtuse angle blade.
(12) having charging means for charging the photoreceptor;
The charging method of the photoconductor by the charging means is a contact method or a proximity method,
The image forming apparatus according to any one of (1) to (11), wherein the charging unit performs AC charging in which an AC voltage is superimposed on a DC voltage.
(13) The image forming apparatus as described in any one of (1) to (12) above, wherein a filler is dispersed in the outermost surface layer of the photoreceptor.
(14) Image formation by integrating a photoconductor and a developing device that develops at least a latent image on the photoconductor with a developer for use in the image forming apparatus according to any one of (1) to (13). A process cartridge configured to be detachable from the apparatus, wherein the photosensitive member is covered with a protective sheet having BN adhered to the surface of the photosensitive member, and then the protective sheet is removed to remove BN on the surface. A process cartridge having an attached photosensitive member attached thereto.

1 is a diagram schematically showing an image forming apparatus according to the present invention. It is a figure which shows the outline of the process cartridge which concerns on this invention. It is the schematic showing another example of the image forming apparatus which concerns on this invention. FIG. 6 is a model diagram when the angle of the tip of the blade on the side in contact with the photoconductor is 90 °. It is a model figure when the front-end | tip of a braid | blade is drawn. It is a model figure in case the angle of the front-end | tip of a braid | blade exceeds 90 degrees (obtuse angle). It is a model figure in case the angle of the front-end | tip of a braid | blade is less than 90 degrees (acute angle). FIG. 3 is a model diagram when a blade contacts a photoconductor in a counter manner. FIG. 6 is a model diagram when the blade is in contact with the photosensitive member by a trailing (trading) method.

  An image forming apparatus according to the present invention includes a charging unit that uniformly charges a photoconductor, a latent image forming unit that forms a latent image on the surface of the charged photoconductor, and a latent image formed on the surface of the photoconductor. Developing means for developing the image with a developer containing at least toner to form a toner image, transfer means for transferring the toner image formed on the surface of the photoreceptor to a transfer target, and the surface of the photoreceptor after transfer An image forming apparatus provided with a cleaning means for removing residual toner, wherein BN is adhered to the surface of the protective sheet of the photosensitive member on the photosensitive member side.

  In particular, BN improves the lubricity between the photosensitive member and the blade and suppresses the fine vibrations of the blade to stabilize the posture of the blade, so that the metal soap powder and toner pass through the blade, and the charging roller It seems that it suppresses the occurrence of streaky abnormal images. Further, blade wear is suppressed by suppressing blade vibration. For this reason, it is sufficient that BN exists only at a portion where the photosensitive member and the blade are in contact with each other.

  In the image forming apparatus of the present invention, it is preferable that a mixture of metal soap and BN is previously attached to the surface of the protective sheet for the photosensitive member on the photosensitive member side.

At the very beginning of image formation, since toner or the like is not present in the photosensitive member, the frictional force between the blade and the photosensitive member tends to be particularly high. In addition to BN, metal soap is also used on the photosensitive member side of the protective sheet for the photosensitive member. By adhering to the surface, metal soap and BN are transferred from the protective sheet to the photosensitive member, and the lubricity between the photosensitive member and the cleaning blade in the very initial stage is higher than when only BN is adhered, which is preferable. However, since the metal soap separates from the blade over time, BN that does not separate from the blade over time exhibits an effect on lubricity. In addition, over time, the toner on the photoconductor contributes to increase the lubricity of the blade and the photoconductor, so that it is possible to maintain high lubricity even when the metal soap is separated.
The substance mixed with BN may be a lubricious substance other than metal soap, or a mixture of BN and toner. There may be one kind of lubricating material to be attached to the protective sheet for the photoreceptor, but a plurality of types of lubricants may be mixed and attached to the protective sheet for the photoreceptor.

In addition, an example of a method of applying (adhering) a mixture of BN or a lubricant to the protective sheet of the photoreceptor will be described.
The method of applying (adhering) BN or a mixture of lubricant to the protective sheet of the photoreceptor is not limited to the following method, but BN or lubricant is applied to a brush (brush) or sponge (cosmetic puff). The mixture may be adhered and applied to the surface of the photosensitive member side of the protective sheet for the photosensitive member. Further, by wrapping a mixture of BN or a lubricant in a fine cloth and hitting the cloth against the surface of the photosensitive member on the photosensitive member side, the surface of the photosensitive member on the photosensitive member side of the protective sheet of BN or lubricant A mixture may be deposited.

The BN to be adhered to the photoreceptor side surface of the protective sheet for the photoreceptor is a particle having a primary particle or secondary particle size of about 10 μm, more preferably a particle of about 2 to 8 μm.
Further, the metal soap to be attached to the surface of the photosensitive member-protecting sheet is preferably about 0.1 μm to several μm.

In the image forming apparatus of the present invention, the mixing ratio of the metal soap and BN previously attached to the surface of the photosensitive sheet of the protective sheet for the photosensitive body is BN of 10% or more, preferably 30 to 90%, by weight. More preferably, it is 50 to 80%.
When the amount of BN is less than 10%, it is not preferable because BN cannot sufficiently maintain the effect of improving the lubricity between the blade and the photoreceptor.

The image forming apparatus of the present invention preferably includes means for supplying metal soap as a protective agent to the image carrier.
In addition to the effect of BN held between the photoconductor and the blade, by supplying metal soap as a protective agent to the photoconductor, the effect of protecting the photoconductor from AC charging can be obtained. It is highly preferred to supply Further, since BN is held between the blade and the photosensitive member, the posture of the blade is maintained, so that the metal soap is prevented from slipping through the blade, so that there is no concern about contamination of the charging roller.

In the image forming apparatus of the present invention, it is preferable that BN is contained in the protective agent supplied to the image carrier, and the mixing ratio of the metal soap and BN is a weight ratio, and BN is 30% or less.
When a protective agent in which BN is mixed with metal soap is used as a protective agent to be supplied to the photoconductor, the lubricity between the photoconductor and the blade is further increased as compared with the case where BN is not added, and the lubricity is It is preferable because it is kept very long. On the other hand, if BN exceeds 30% by weight, it is not preferable because BN adheres too much on the photoreceptor and causes problems. From the viewpoint of cost, the blending ratio of BN is preferably 10% or less.

  Moreover, when BN is contained in a mixture of zinc stearate and zinc palmitate, alumina may also be contained together. When alumina is contained, BN and a mixture of zinc stearate and zinc palmitate supplied excessively on the photoreceptor are polished, which is preferable. The alumina to be contained is 2 to 15%, preferably 3 to 10%, more preferably 4 to 8% based on the weight of the mixture of zinc stearate and zinc palmitate. If the alumina to be contained exceeds 15% by weight of the mixture of zinc stearate and zinc palmitate, it is not preferable because alumina tends to damage the photoreceptor, and the alumina to be contained is zinc stearate and zinc palmitate. If it is less than 2% with respect to the weight of the mixture, the effect of polishing the mixture of BN and zinc stearate and zinc palmitate is not sufficiently exhibited, which is not preferable.

  Moreover, as a particle size of an alumina, it is 0.05-0.5 micrometer, More preferably, it is 0.1-0.4 micrometer, More preferably, it is 0.2-0.3 micrometer. When the alumina particle size is less than 0.05 μm, the effect of polishing BN and the mixture of zinc stearate and zinc palmitate is not sufficiently exhibited, which is not preferable, and the alumina particle size exceeds 0.5 μm. Alumina itself is not preferable because it easily damages the photoreceptor.

In the image forming apparatus of the present invention, the metal soap is preferably a mixture of zinc palmitate and zinc stearate.
The mixing ratio of zinc stearate and zinc palmitate in the protective agent used in the image forming apparatus of the present invention is preferably 75:25 to 40:60 (weight ratio), more preferably 66:34 to 40: 60 (weight ratio).

The reason why it is preferable to use a mixture of zinc stearate and zinc palmitate is that when the process of applying zinc stearate on the photoreceptor is observed, the block-like zinc stearate is scraped with a brush and finely divided. Although it is stretched by the blade, if the linear velocity of the photoreceptor is increased, the method of stretching the zinc stearate may not catch up. However, by adding zinc palmitate having a molecular weight smaller than that of zinc stearate to zinc stearate, the protective agent (zinc stearate and zinc palmitate) is applied onto the photoreceptor even if the linear velocity of the photoreceptor is high. It is stretched with a blade and can sufficiently cover the photoconductor.
Zinc stearate and zinc palmitate are both fatty acid metal salts, but in the fatty acid portion, stearic acid has 18 carbon atoms and palmitic acid has 16 carbon atoms. Therefore, zinc stearate and zinc palmitate are similar in structure and are compatible with each other, and behave almost as the same material.

Since zinc palmitate has a lower melting point than zinc stearate, if the zinc stearate contains a certain amount or more of zinc palmitate, the protective agent is easily stretched by the blade. In addition, as the linear velocity of the photoconductor increases, the charging energy falling on the photoconductor, particularly the AC charging energy, becomes stronger. Therefore, in order to enhance the protective effect of the photoconductor by the protective agent, the protective agent on the photoconductor It is necessary to increase the thickness.
It is said that zinc stearate does not adhere randomly on the photoreceptor, but is stable when attached with two molecules. That is, even if zinc stearate is applied on the photoreceptor, it is saturated at the thickness of two molecules of zinc stearate. Here, when zinc palmitate having a slightly smaller molecular length than zinc stearate is contained in a certain amount or more, the height of the molecular layer is not constant, and the low part and the high part coexist. Then, the next molecule enters the lower part and forms a molecular layer. Therefore, as a result, a protective agent layer thicker than two molecules can be formed, and the protective effect of the photoreceptor is improved.

The image forming apparatus of the present invention preferably includes a blade (coating blade) as means for supplying a protective agent separately from the cleaning means.
Although it is possible to supply the protective agent with only the cleaning blade, the cleaning blade also cleans the toner, so the toner and protective agent are mixed on the cleaning blade, and a film of the protective agent is formed on the photoreceptor. Is not enough. Therefore, by providing two blades, a toner cleaning blade and a protective agent supply and application blade (application blade), the functions are separated, and the toner cleaning and the supply of the protective agent onto the photoreceptor can be performed more efficiently. Can be done.

Moreover, it is preferable that BN or a mixture of metal soap and BN adheres to the coating blade before use.
Since BN adheres to the coating blade, the lubricity is improved, which contributes to the extension of the service life of the coating blade and the photoreceptor. In addition, the presence of BN prevents slip-through, which contributes to prevention of charging roller contamination. Even in the coating blade, BN improves the lubricity between the photoconductor and the blade and suppresses fine vibrations of the blade, thereby stabilizing the posture of the blade and allowing the powder of protective agent such as metal soap to pass through the blade. Then, it adheres to the charging roller and suppresses the occurrence of streaky abnormal images. Further, blade wear is suppressed by suppressing blade vibration.

  In the present invention, it is preferable that the blade as a means for supplying the protective agent is in contact with the image carrier at an angle similar to a counter system. Here, the angle similar to the counter system indicates that the blade is in contact with the rotation (advance) direction of the photosensitive member at an angle of less than 90 ° as shown in FIG. An angle similar to the (trading) system indicates that the blade is in contact with the rotation (advance) direction of the photosensitive member at an angle exceeding 90 ° as shown in FIG. It is preferable that the blade, which is a means for supplying the protective agent, is in contact with the image carrier at an angle similar to that of the counter system, because BN is prevented from adhering to the photoreceptor.

In the present invention, the blade that is a means for supplying the protective agent is preferably an obtuse angle blade. Usually, a blade tip angle of 90 ° has been used because of good manufacturing efficiency, but an obtuse angle blade is excellent in the following points.
FIG. 4A is a model diagram illustrating a case where the tip of the blade in contact with the photoconductor is a normal right angle (90 degrees). As shown in FIG. 4A, when the blade tip is at a right angle, the blade tip is likely to be pulled in by rotation of the photosensitive member (FIG. 4-2: Model diagram when the blade tip is pulled in). Since the blade tip angle at the contact portion with the photosensitive member is large (FIG. 4-3) and the blade is hardly pulled in, the blade stably contacts the photosensitive member. It is considered that the cleaning property is improved because of the low vibration. Similarly, an acute angle blade (FIG. 4-4) having a sharp blade tip is not preferable because the blade tip is easily pulled in.
As described above, when the obtuse blade is used, the cleaning property is improved and the phenomenon that toner, metal soap, and BN slip through the blade is suppressed, so that it is possible to prevent BN from slipping and being excessively attached on the photoreceptor. In addition, since the toner and the protective agent do not pass through very much, the charging roller contamination is also suppressed, which is very preferable.

  In the image forming apparatus of the present invention, the charging method of the photoconductor is a contact method or a proximity method, and the charging unit preferably performs AC charging in which an AC voltage is superimposed on a DC voltage. In the case of the DC charging method, the photosensitive member is charged by only one positive discharge while passing through the charger. However, in the case of using the AC charging method, several hundred to several times per second depending on the frequency. Since the photosensitive member is charged by repeating positive and negative discharges 1000 times, the hazard received by the photosensitive member is very large compared to the DC charging method, and the deterioration is particularly severe. Therefore, BN is interposed between the blade and the photosensitive member. The effect of preventing the deterioration of the photoreceptor is higher than in the case of DC charging.

In the image forming apparatus of the present invention, it is preferable that fillers (fine particles) are dispersed in the outermost surface layer of the photoreceptor.
When there is a filler, since the blade is particularly likely to deteriorate, the effect of preliminarily attaching BN to the protective sheet of the photoreceptor is high. In addition, when a protective agent for metal soap is attached to the photoconductor, if there is a filler in the surface of the photoconductor, it is difficult to form a uniform protective layer film such as metal soap because of the irregularities on the surface of the photoconductor. Since BN is on the blade from the very beginning, vibration of the blade is prevented and the posture of the blade is stabilized. Therefore, even if there is a filler, it is easy to form a uniform film throughout.

  In the present invention, the protective sheet for the photosensitive member is easily damaged, so that the surface of the photosensitive member is protected, and the electrophotographic photosensitive member is exposed to external light. Since it tends to occur, it is mounted on the photoconductor after the photoconductor is manufactured for light shielding.

  When using the photoconductor, remove the protective sheet for the photoconductor. The timing for removing the protective sheet for the photosensitive member may be before or after the photosensitive member is attached to the apparatus (or the process cartridge). In particular, when the photosensitive sheet is attached to the apparatus (or process cartridge) with the protective sheet wrapped around the photosensitive element, and then the protective sheet is removed, the photosensitive element is prevented from being damaged when the photosensitive element is attached. This is preferable because it can prevent deterioration of the electrostatic characteristics of the photoreceptor due to light fatigue until the protective sheet is removed.

The photosensitive member protective sheet used in the present invention is not particularly limited as long as it can suppress scratches and the like caused by an external force when transporting the electrophotographic photosensitive member, and has light shielding properties. It is not something. On the other hand, the protective sheet for the photoreceptor in the present invention is preferably a material that can be easily broken because it can be partly broken and can be removed together with the adhesive tape.
Therefore, as a suitable sheet for protecting a photoreceptor, black light-shielding paper containing carbon black or the like can be given.

The reason for this is that such a black light-shielding paper can effectively prevent the electrophotographic photosensitive member from being exposed to external light, and an adhesive tape is attached to the black light-shielding paper. This is because the part can be easily separated.
Moreover, it is because the breakability of the black shading paper can be easily adjusted only by changing the addition amount of carbon black or the like in the black shading paper.
In addition, black shading paper is inexpensive and can be easily discarded or incinerated.

Furthermore, if it is a black shading paper, the electroconductivity of the sheet for protecting the photoconductor can be improved by the action of carbon black or the like. Therefore, generation of static electricity can be suppressed, and deterioration of the electrophotographic photoreceptor due to the static electricity can be effectively suppressed.
Further, the protective sheet for the photoreceptor used in the present invention may be a sheet other than paper, or a synthetic resin sheet such as polyethylene. The protective sheet for the photoconductor can be substituted if it is a material that is less rigid than the electrophotographic photoconductor that is the package.

Further, the lateral length of the protective sheet for the photosensitive member, that is, the lateral width can cover the entire photosensitive layer portion of the electrophotographic photosensitive member with a flange to be packed, and is long enough to expose the flange portion. It is preferable.
This is because the photosensitive layer is prevented from being damaged or exposed to external light, and the electrophotographic photosensitive member can be easily assembled to the image forming apparatus while being packed.

  Further, the longitudinal length of the protective sheet for the photosensitive member may be long enough to be wound around the electrophotographic photosensitive member and packed.

The thickness of the protective sheet for the photosensitive member is determined in consideration of the mechanical protection property of the electrophotographic photosensitive member and the light shielding property against external light, and also considers the breakability that can be removed together with the adhesive tape. Is preferably determined.
Therefore, it is preferable to set the thickness of the protective sheet for the photoreceptor to a value in the range of 0.05 to 0.5 mm.

That is, when the thickness of the protective sheet of the photosensitive member is less than 0.05 mm, it may be difficult to sufficiently exhibit the mechanical properties and the light shielding properties with respect to the electrophotographic photosensitive member. . On the other hand, when the thickness of the protective sheet for the photoconductor exceeds 0.5 mm, not only the breakability of the protective sheet for the photoconductor is deteriorated but also the handling property becomes difficult and the packing property may be lowered. Because there is.
Accordingly, the thickness of the protective sheet for the photoreceptor is more preferably set to a value within the range of 0.08 to 0.3 mm, and further preferably set to a value within the range of 0.1 to 0.2 mm. .

Specific embodiments of the present invention will be described below with reference to the drawings.
[Embodiment 1]
FIG. 1 is a schematic configuration diagram showing a main part of an example of the main part of an image forming apparatus equipped with a protective agent coating apparatus according to the present invention.
The protective agent coating apparatus 2 disposed opposite to the drum-shaped photosensitive member 1 serving as an image carrier has a bar-shaped protective agent mainly composed of zinc stearate for protecting the photosensitive member. A protective agent bar 21 having a hexagonal column shape and the like, a protective agent bar support guide 25 that supports the protective agent bar 21 so as not to swing back and forth, and a brush 22a that contacts the protective agent bar 21. The protective agent supply member 22 for supplying the protective agent transferred from 21 to the brush 22a to the photosensitive member 1 and the brush of the protective agent supply member 22 by pressing the protective agent bar 21 against the brush 22a of the protective agent supply member 22 It is mainly composed of a pressing force applying mechanism (for example, a spring, a spring, etc.) 23 for shifting to 22a and a protective layer forming mechanism 24 for thinning the protective agent supplied onto the photosensitive member by the protective agent supply member 22. Yes. The protective agent bar 21 used in the present invention is produced by a melt molding method in which a protective agent is melted and then charged in a mold and cooled, or a compression molding method in which a protective agent powder is compressed.
In FIG. 1, reference numeral 4 denotes a cleaning device as a cleaning means for the photosensitive member, which is installed upstream of the protective agent applying device 2 in the rotation direction of the photosensitive member. Since the surface of the photosensitive member is cleaned so that the protective agent can be applied satisfactorily, it can be regarded as a constituent member of the protective agent coating apparatus 2.

  The protective agent bar 21 according to the present invention is pressed against the brush 22a of the protective agent supply member 22 by a pressing force from a pressing force applying mechanism 23 including a pressing member such as a spring or a spring, and the protective agent bar 21 is applied to the brush 22a. The protective agent is transferred. At this time, the supply amount of the protective agent can be changed by changing the spring and the pressing force of the spring. The protective agent supply member 22 rotates with a linear velocity difference with the photosensitive member 1 and rubs the surface of the photosensitive member with the tip of the brush 22a. At this time, the protective agent held on the surface of the brush 22a of the protective agent supply member 22 is removed. , And supplied to the surface of the photoreceptor 1.

  Further, since the protective agent supplied to the surface of the photoconductor 1 may not be a sufficient protective layer at the time of supply, the protective agent on the surface of the photoconductor is in the form of a blade in order to form a more uniform protective layer. The protective layer forming mechanism 24 having a member 24a and a pressing member 24b such as a spring or a spring that presses the blade 24a against the surface of the photosensitive drum 1 is thinned to form a protective layer on the surface of the photosensitive member. A lubricious substance is attached to the blade 24a in advance.

  The term “lubricating substance” as used herein may be anything as long as it is a powder generally imparting lubricity, but preferred substances include zinc stearate, magnesium stearate, iron stearate, calcium stearate, and laurin. Fatty acid metal salts such as zinc acid, zinc palmitate, zinc oleate; polytetrafluoroethylene (PTFE), polyperfluoroalkyl ether (PFA), perfluoroethylene-perfluoropropylene copolymer (FEP), polyvinylidene fluoride (PVdF), fluorine-based resins such as ethylene-tetrafluoroethylene copolymer (ETFE); silicone resins such as polymethyl silicone and polymethylphenyl silicone; acrylic resins; ethylene acrylic resins; mica, boron nitride (BN), Molybdenum disulfide Buden, tungsten disulfide, kaolin, montmorillonite, calcium fluoride, inorganic solid lubricant such as graphite and the like.

  As the powdery lubricant, it is preferable to use an inorganic solid lubricant. This is because these inorganic solid lubricants have little influence on the charging characteristics and fluidity of the developer, and also have a very high effect of protecting the surface of the image carrier during film formation.

  In addition, inorganic solid lubricants have higher resistance to electrical stress during charging and are less prone to deterioration compared to fatty acid metal salts and other resin fine particle systems. This is because the lubricity is maintained and the effect of extending the life of a cleaning member such as a cleaning blade is very large.

Further, among the inorganic solid lubricants, boron nitride (BN) is particularly preferably used because it has a high effect of stabilizing the posture of the blade and preventing slipping of toner or the like.
These inorganic solid lubricants may be subjected to surface treatment for the purpose of improving hydrophobicity.
The protective layer forming mechanism 24 uses a counter method, and the blade-like member 24a is in contact with the surface of the photosensitive member by the counter method.

As described above, by supplying an appropriate amount of the protective agent to the photosensitive member 1 and making the layer thin by the protective layer forming mechanism 24, the protective agent is easily held on the photosensitive member. As a result, an image forming apparatus capable of outputting a high-quality image over a long period of time without causing an abnormal image due to dirt or the like of the charging unit (for example, a charging roller), with less frequent replacement of consumables.
Further, instead of the protective agent bar, the protective agent powder can be directly supplied to the surface of the photoreceptor. In this case, a container that holds the protective agent powder and a protective agent conveying device that conveys the protective agent powder are required, and a protective agent bar, a pressing force applying mechanism, and a protective agent supply member are not necessary. As the protective agent conveying device, existing powder conveying means such as a pump and an auger can be used.

  The material of the blade-like member (hereinafter referred to as blade) 24a used for the protective layer forming mechanism 24 is not particularly limited, and for example, urethane rubber, hydrin rubber, silicone rubber, fluorine, which are generally known as cleaning blade materials, are used. Elastic bodies such as rubber can be used alone or in combination. In addition, these rubber blades may be coated or impregnated with a low friction coefficient material at the contact portion with the photoreceptor 1. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

These blades 24a are fixed to the blade support 24c by an arbitrary method such as adhesion or fusion so that the tip portion can be pressed against the surface of the photoreceptor. The thickness of the blade 24a is not uniquely defined in consideration of the force applied by pressing, but is preferably about 0.5 to 5 mm, more preferably about 1 to 3 mm. .
Further, the length of the blade 24a that protrudes from the support 24c and can bend, that is, the so-called free length, is also applied by pressing in the same manner. If it is about 15 mm, it can be preferably used, and if it is about 2-10 mm, it can be used more preferably.

Other configurations of the protective layer forming blade 24a include coating, dipping, and the like on the surface of an elastic metal blade such as a spring plate with a coupling agent, a primer component, or the like as necessary. It may be formed by the method described above, and if necessary, heat curing or the like may be performed, and if necessary, surface polishing or the like may be performed.
The thickness of the elastic metal blade is preferably about 0.05 to 3 mm, and more preferably about 0.1 to 1 mm.
Moreover, in an elastic metal blade, in order to suppress the twist of a braid | blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment.
As a material for forming the surface layer, fluorine resin such as PFA, PTFE, FEP, PVdF, silicone elastomer such as fluorine rubber, methylphenyl silicone elastomer, and the like can be used together with a filler, if necessary. It is not limited to this.

  Further, the force for pressing the blade 24a against the photoreceptor 1 by the pressing member 24b of the protective layer forming mechanism 24 is sufficient as the protective agent on the surface of the photoreceptor is extended to become a protective layer or a protective film. The pressure is preferably 5 gf / cm or more and 80 gf / cm or less, and more preferably 10 gf / cm or more and 60 gf / cm or less.

A brush-like member (hereinafter referred to as a brush) 22a is preferably used as the protective agent supply member 22. In this case, the brush fiber is flexible in order to suppress mechanical stress on the surface of the photoreceptor. It is preferable to have
As a specific material of the flexible brush fiber, one or more kinds can be selected and used from generally known materials. Specifically, polyolefin resins (for example, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (for example, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and Polyvinyl chloride); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene-butadiene resin; fluorine resin (for example, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); Polyester; Nylon; Acrylic; Rayon; Polyurethane; Polycarbonate; Phenol resin; Amino resin (eg urea-formaldehyde resin, melamine) Fat, benzoguanamine resins, urea resins, polyamide resins); Among such, may be a resin having flexibility.
Also, in order to adjust the degree of bending, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. are used in combination. Also good.

  The support 22b of the protective agent supply member 22 includes a fixed type and a rotatable roll. As the roll-shaped supply member, for example, there is a roll brush in which a tape having brush fibers piled is wound around a metal core in a spiral shape. The brush fiber has a fiber diameter of 10 to 500 μm, more preferably 20 to 300 μm. If the thickness is less than 10 μm, the supply speed of the protective agent is very slow, which is not preferable. If the thickness exceeds 500 μm, the number of brush fibers that can exist per unit area becomes smaller. The unevenness of the coating becomes noticeable, the photoconductor is easily damaged when the brush hits the photoconductor, and the power to scrape off the protective agent becomes strong, so the life of the protective agent is shortened and supplied to the photoconductor This is not preferable because the protective agent is made into large particles, and the particles supplied to the photosensitive member move to the charging roller to contaminate the charging roller, or the torque for rotating the brush and the photosensitive member becomes larger. .

  The length of the fibers of the brush is 1 to 15 mm, preferably 3 to 10 mm. If the length of the brush fiber is less than 1 mm, the cored bar of the brush and the photoconductor are arranged very close to each other, so the cored bar comes into contact with the image carrier and the photoconductor is easily damaged. If it exceeds, the force that scrapes off the protective agent at the tip of the brush fiber and the force that the tip of the brush fiber hits the photoconductor will be weak, making it difficult to supply a sufficient amount of protective agent and making it easier for the fibers of the brush to come off. It is not preferable.

The brush density is 10,000 to 300,000 per square inch (1.5 × 10 ^{7 to} 4.5 × 10 ⁸ per square meter). When the brush density is less than 10,000 per square inch, it is not preferable because the coating unevenness in the place where the brush hits the photoconductor and the place where the brush does not hit becomes remarkable, or it becomes difficult to supply a sufficient amount of the protective agent. Also, in order to increase the brush density to more than 300,000 per square inch, the diameter of the brush fiber needs to be very small, which is not preferable.

  The protective agent supply member 22 is preferably made of a material having a high brush density as much as possible from the viewpoint of supply uniformity and stability, and one fiber is made from several to several hundreds of fine fibers. Is also preferable. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

  Among these protective agent supply members, a brush made of a single fiber of 28 to 43 μm, preferably 30 to 40 μm is most preferable because of high efficiency of supplying the protective agent. Since fibers are often produced by twisting, the diameter of the fibers is not uniform, and therefore, denier and decitex units have been used. However, in the case of monofilaments, the fiber diameter is constant, so that it is preferable to define the fiber diameter in order to define the protective agent supply member.

  When the diameter of the single fiber is smaller than 28 μm, the efficiency of supplying the protective agent is lowered, and when the diameter of the single fiber exceeds 43 μm, the rigidity of the single fiber becomes too high and the photoreceptor is easily damaged. Moreover, it is preferable that 28-43 micrometers monofilament is planted as perpendicular | vertical as possible with respect to a metal core, and when manufacturing a brush, it is manufactured by what is called electrostatic flocking using static electricity. Is preferred. The electrostatic flocking is performed by applying an adhesive on the core metal of the brush and charging the core metal, thereby flying single fibers of 28 to 43 μm by electrostatic electric force, and flocking the adhesive on the core metal. This is a method of curing the adhesive. Thus, a brush in which 50,000 to 600,000 hairs are implanted per square inch by electrostatic flocking can be suitably used.

  In addition, a coating layer may be provided on the surface of the brush 22a as necessary for the purpose of stabilizing the surface shape, environmental stability, and the like of the brush 22a. As a component constituting the coating layer, it is preferable to use a coating layer component that can be deformed according to the bending of the brush fiber, and these are not limited as long as the material can maintain flexibility. Polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc .; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, Polyvinyl and polyvinylidene resins such as polyvinyl carbazole, polyvinyl ether, and polybiliketones; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds or modified products thereof (for example, alkyd resins, Modified products by reester resin, epoxy resin, polyurethane, etc.); Fluororesin such as perfluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamide; polyester; polyurethane; polycarbonate; urea-formaldehyde resin, etc. Amino resins; epoxy resins, composite resins of these, and the like.

[Embodiment 2]
Next, an embodiment of a process cartridge and an image forming apparatus according to the present invention will be described.
FIG. 2 is a cross-sectional view for explaining the outline of the configuration example of the process cartridge provided with the protective agent coating device provided in the image forming unit of the image forming apparatus according to the present invention.
An image forming unit 10 shown in FIG. 2 includes a drum-shaped photoreceptor 1 as an image carrier, a charging device (a charging roller in the illustrated example) 3 as a charging unit that charges the photoreceptor 1, and a charged photosensitive member. A latent image forming means (not shown) for forming an electrostatic latent image by irradiating the body 1 with laser light L or the like, and development for developing the electrostatic latent image on the photosensitive member 1 with a toner into a visible image A developing device 5 as a means, a transfer means 6 for transferring a toner image on the photoreceptor 1 to a transfer medium (or intermediate transfer medium) 7, and a cleaning means for removing toner remaining on the surface of the photoreceptor 1 after the transfer. The cleaning device 4 and the protective agent coating device 2 disposed in a portion from the cleaning device 4 to the charging device 3. The image forming unit 10 uses a process cartridge 11 in which a protective agent coating device 2, a charging device 3, a developing device 5, and a cleaning device 4 are provided in a cartridge together with the photoreceptor 1. In the present invention, the cleaning device 4 cleans the surface of the photoreceptor before applying the protective agent so that the protective agent can be applied satisfactorily. Can be seen.

  If BN is attached in advance to the surface of the photosensitive member protective sheet mounted on the process cartridge, the BN is transferred from the photosensitive member side surface of the photosensitive member protective sheet to the photosensitive member. Since each member such as a charging roller and a blade has a long life and a long life as a process cartridge, the replacement frequency can be reduced, which is very preferable. As can be seen from this, it is particularly effective in an integrated system such as a process cartridge to attach BN to the surface of the photosensitive member side of the protective sheet for the photosensitive member.

  In FIG. 2, a charging device 3, a latent image forming unit (not shown), and a developing device 5 constitute an image forming unit, and the charging device 3 is switched to a direct current (DC) voltage by a high voltage power source (not shown). AC) charging roller of an AC charging system to which a voltage superposed is applied. Further, the developing device 5 includes a developing roller 51 that is a developer carrying member that carries and conveys toner particles or a mixture of toner particles and carrier particles, and a developer stirring and conveying member that conveys the developer while stirring. 52, 53 and the like.

As in FIG. 1, the protective agent coating device 2 disposed facing the photoconductor 1 includes a protective agent bar 21, a protective agent supply member 22, a pressing force applying mechanism 23, a protective layer forming mechanism 24, and a protective agent bar. Mainly composed of a protective agent bar support guide 25 and the like that support 21 so as not to swing back and forth.
The photosensitive member 1 has a surface on which partially deteriorated protective agent, toner component, and the like remain after the transfer process, but the surface residue is cleaned and cleaned by the cleaning member 41 of the cleaning device 4. In FIG. 2, the blade-like cleaning member 41 is supported by a cleaning pressing mechanism 42 and abuts at an angle similar to a so-called counter type (leading type). Further, a blade-like member (blade) 24a of the protective layer forming mechanism 24 is also brought into contact with an angle similar to a counter type.

  The protective agent of the protective agent bar 21 is supplied by the brush-like protective agent supply member 22 to the surface of the photosensitive member from which the residual toner and the deteriorated protective agent have been removed by the cleaning device 4, and is supplied to the photosensitive member surface. The protective agent is thinned by the blade 24a of the protective layer forming mechanism 24 to form a protective layer.

  The photosensitive member 1 on which the protective layer is formed is charged by the charging roller 3 and then an electrostatic latent image is formed by exposure with a laser beam L or the like, and is developed with the toner of the developing device 5 as a developing unit to be visualized. Then, the image is transferred to a transfer medium (or intermediate transfer medium) 7 such as transfer paper by a transfer device (transfer roller or the like) 6 which is transfer means outside the process cartridge.

As the charging means (charging device) 3 used in the process cartridge 11 of the present invention, a charging roller having a small device and generating less oxidizing gas such as ozone is used.
The charging roller 3 is installed in contact with the photosensitive member 1 or in a non-contact state close to 20 to 100 μm, and charges the photosensitive member 1 by applying a voltage between the charging roller 3 and the photosensitive member 1. The voltage applied between the charging roller 3 and the photoreceptor 1 uses AC charging in which an AC voltage is superimposed on a DC voltage. When AC charging is performed, discharge occurs several hundred times or more per second between the photosensitive member 1 and the charging roller 3, so that the photosensitive member is easily deteriorated by discharge. Further, even when a protective agent is applied to the photoreceptor 1, the protective agent is likely to deteriorate and disappear due to electric discharge, so that a constant amount of protective agent is always applied on the photoreceptor 1. Very important.

The charging roller is preferably composed of a polymer layer and a surface layer on a conductive support.
The conductive support functions as an electrode and a support member of the charging roller 3. For example, a metal or an alloy such as aluminum, copper alloy, stainless steel, iron subjected to a plating treatment with chromium, nickel, or a conductive agent is used. It is made of a conductive material such as an added resin.

The polymer layer is preferably a conductive layer having a resistance of 10 ⁶ to 10 ⁹ Ωcm, and a polymer material mixed with a conductive agent to adjust the resistance is used. As the polymer of the polymer layer of the charging roller used in the image forming apparatus of the present invention, polyester-based, olefin-based thermoplastic elastomer, polystyrene, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene Styrenic thermoplastic resins such as acrylonitrile copolymer, isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide Copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene Emissions copolymer rubber, natural rubber, and blends the rubber material. Among the rubber materials, silicone rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, acrylonitrile-butadiene copolymer rubber and blended rubber thereof are preferably used. These rubber materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used. Examples of electronic conductive agents include carbon blacks such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; tin oxide, indium oxide, titanium oxide Examples thereof include fine powders such as various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals Can be mentioned. These conductive agents may be used alone or in combination of two or more. Moreover, the addition amount is not particularly limited, but in the case of the electronic conductive agent, it is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the polymer, and in the range of 15 to 25 parts by mass. More preferably. On the other hand, in the case of the ionic conductive agent, it is preferably in the range of 0.1 to 5.0 parts by mass, and in the range of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the polymer. Is more preferable.

The polymer material constituting the surface layer is not particularly limited as long as the dynamic ultrafine hardness of the surface of the charging roller 3 is 0.04 or more and 0.5 or less, as described above. Vinylidene, tetrafluoroethylene copolymer, polyester, polyimide, silicone resin, acrylic resin, polyvinyl butyral, ethylene tetrafluoroethylene copolymer, melamine resin, fluororubber, epoxy resin, polycarbonate, polyvinyl alcohol, cellulose, polyvinylidene chloride , Polyvinyl chloride, polyethylene, ethylene vinyl acetate copolymer and the like.
Among these, polyamide, polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, and polyimide are preferably used from the viewpoint of releasability with toner and the like. The above polymer materials may be used alone or in combination of two or more. Further, the number average molecular weight of the polymer material is preferably in the range of 1,000 to 100,000, and more preferably in the range of 10,000 to 50,000.

  The surface layer is formed as a composition by mixing the polymer material with the conductive agent used in the conductive elastic layer and various fine particles. As the fine particles, metal oxides such as silicon oxide, aluminum oxide, barium titanate and complex metal oxides, and polymer fine powders such as tetrafluoroethylene and vinylidene fluoride are used alone or in combination. It is not limited to.

The developing means used in the process cartridge of the present invention contacts the developer with the photosensitive member, and develops the latent image formed on the photosensitive member into a toner image. As the developer, a two-component developer composed of a toner and a carrier or a one-component developer not containing a carrier can be used.
For example, as shown in FIG. 2, in the developing device 5, a developing roller 51 as a developer carrying member is partially exposed from an opening of the casing.

  The toner replenished from the toner bottle (not shown) into the developing device 5 is conveyed while being agitated with the carrier by the agitating and conveying screws 52 and 53 and is carried on the developing roller 51. The developing roller 51 includes a magnet roller as magnetic field generating means and a developing sleeve that rotates coaxially therearound. The carrier in the developer is brought up on the developing roller 51 by the magnetic force generated by the magnet roller, and is conveyed to the developing region facing the photosensitive drum 1. Here, the developing roller 51 moves in the same direction at a linear velocity faster than the surface of the photosensitive drum 1 in the developing region. The carrier spiked on the developing roller 51 supplies the toner adhered to the carrier surface to the surface of the photosensitive drum 1 while rubbing the surface of the photosensitive drum 1. At this time, a developing bias is applied to the developing roller 51 from a power source (not shown), whereby a developing electric field is formed in the developing region. Then, between the electrostatic latent image on the photosensitive drum 1 and the developing roller 51, an electrostatic force toward the electrostatic latent image side acts on the toner on the developing roller 51. As a result, the toner on the developing roller 51 adheres to the electrostatic latent image on the photosensitive drum 1. By this adhesion, the electrostatic latent image on the photosensitive drum 1 is developed into a toner image.

[Embodiment 3]
Next, another embodiment of the image forming apparatus according to the present invention will be described.
FIG. 3 is a schematic configuration diagram illustrating a configuration example of the image forming apparatus 100 including the protective agent coating apparatus of the present invention.
The image forming apparatus 100 includes an image forming apparatus main body (printer unit) 110 that performs image formation, a document reading unit (scanner unit) 120 installed on the upper part of the main unit 110, and an automatic document supply unit installed thereon. A paper device (ADF) 130 and a paper feed unit 200 installed at the lower part of the image forming apparatus main body 110 are provided, and have a function of a copying machine. The image forming apparatus 100 has a communication function with an external device, and can be used as a printer or a scanner by connecting to a personal computer or the like outside the device. Further, it can be used as a facsimile by connecting to a telephone line or an optical line.

  In the image forming apparatus main body 110, four image forming units (image forming stations) 10 having the same configuration and different toner colors of the developing device 5 are arranged in parallel, and the four image forming units 10 have different toner colors. An image (for example, an image of yellow (Y), magenta (M), cyan (C), and black (K)) is formed, and a toner image of each color is superimposed on a transfer medium or an intermediate transfer medium and transferred to obtain multiple colors or A full color image can be formed. In the example of FIG. 3, the four image forming units 10 are juxtaposed along the belt-like intermediate transfer medium 7 stretched around a plurality of rollers, and each color formed by each image forming unit is provided. The toner image is once superimposed on the intermediate transfer medium 7 and transferred, and then transferred to a sheet-like transfer medium such as paper by the secondary transfer device 12.

  The image forming unit 10 for each color has the same configuration as that in FIG. 2, and the protective agent coating device 2, the charging device 3, and the latent image forming device 8 are arranged around the drum-shaped photoconductor 1 (1Y, 1M, 1C, 1K). An exposure unit such as a laser beam from the laser beam, a developing device 5, a primary transfer device 6, and a cleaning device 4 are arranged. Similarly to FIG. 2, each color image forming unit 10 includes a process car in which a protective agent coating device 2 (including a cleaning device 4), a charging device 3, and a developing device 5 are provided in the cartridge together with the photoreceptor 1. Ridge 11 is used. The process cartridge is detachably attached to the image forming apparatus main body 110.

Next, the operation of the image forming apparatus shown in FIG. 3 will be described. Here, a series of processes for image formation will be described using a negative-positive process. Since the operation of each image forming unit is the same, the operation of one image forming unit will be described here.
The drum-shaped photoreceptor 1, which is an image carrier represented by an organic photoreceptor (OPC) having an organic photoconductive layer, is neutralized by a neutralizing lamp (not shown) or the like, and a charging member (for example, a charging roller) is used. The charging device 3 is uniformly charged negatively.
When the charging device 3 charges the photoreceptor 1, a voltage of an appropriate magnitude suitable for charging the photoreceptor 1 to a desired potential from a voltage application mechanism (not shown) to the charging member or A charging voltage in which an AC voltage is superimposed on this is applied.

The charged photoreceptor 1 is a laser beam irradiated by a laser scanning type latent image forming apparatus 8 including, for example, a plurality of laser light sources, a coupling optical system, an optical deflector, a scanning imaging optical system, and the like. Then, a latent image is formed (the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential).
That is, laser light emitted from a laser light source (for example, a semiconductor laser) is deflected and scanned by an optical deflector composed of a polygonal polygonal mirror (polygon) that rotates at high speed, thereby forming a scanning image formed of a scanning lens, a mirror, and the like. The surface of the photoconductor 1 is scanned in the rotation axis direction (main scanning direction) of the photoconductor 1 via the optical system.

The latent image formed in this way is developed with a developer made of toner particles or a mixture of toner particles and carrier particles supplied onto the developing sleeve of the developing roller 51 which is a developer carrying member of the developing device 5. A toner visible image is formed.
At the time of developing the latent image, a voltage of an appropriate magnitude or an AC voltage is applied to the developing sleeve of the developing roller 51 from a voltage application mechanism (not shown) between the exposed portion and the non-exposed portion of the photoreceptor 1. A superimposed developing bias is applied.

  The toner image formed on the photoreceptor 1 of the image forming unit 10 corresponding to each color by the above operation is sequentially superimposed on the intermediate transfer medium 7 by the primary transfer device 6 composed of a transfer roller or the like for primary transfer. Is done. On the other hand, in synchronization with the image forming operation and the primary transfer operation, the paper feed roller 202 and the separation roller are selected from the paper feed cassettes selected from the multi-stage paper feed cassettes 201a, 201b, 201c, and 201d of the paper feed unit 200. A sheet-like transfer medium such as paper is fed by a paper feed mechanism 203, and is conveyed to a secondary transfer unit via conveyance rollers 204, 205, 206 and registration rollers 207. In the secondary transfer unit, the toner image on the intermediate transfer medium 7 is secondarily transferred to the transferred transfer medium by a secondary transfer device (for example, a secondary transfer roller) 12. In the above transfer step, it is preferable that a potential having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 6 and the secondary transfer device 12 as a transfer bias.

  After the secondary transfer, the transfer medium is separated from the intermediate transfer medium 7 to obtain a transfer image. Further, the toner particles remaining on the photoreceptor 1 after the primary transfer are collected into the toner collection chamber in the cleaning device 4 by the cleaning member 41 of the cleaning device 4. Further, the toner particles remaining on the intermediate transfer medium 7 after the secondary transfer are collected into the toner collection chamber in the cleaning device 9 by the cleaning member of the belt cleaning device 9.

  The image forming apparatus 100 shown in FIG. 3 is a so-called tandem type intermediate transfer type image forming apparatus in which a plurality of the above-described image forming units 10 are arranged along the intermediate transfer medium 7. A plurality of toner images of different colors sequentially produced on the respective photoreceptors 1 (1Y, 1M, 1C, 1K) are once transferred onto the intermediate transfer medium 7 and then transferred like a paper at a time. Transfer to media. The transfer medium onto which the toner image has been transferred is sent to the fixing device 14 by the conveying device 13 and the toner is fixed by heat or the like. The fixed transfer medium is discharged to a paper discharge tray 17 by a transport device 15 and a paper discharge roller 16. The image forming apparatus 100 also has a double-sided printing function. During double-sided printing, the conveyance path downstream of the fixing device 9 is switched, and the transfer medium on which the image on one side is fixed is transferred to the front and back sides via the double-sided conveyance apparatus 210. The paper is reversed, and is fed again to the secondary transfer unit by the transport roller 206 and the registration roller 207, and the image is transferred to the back side. The transfer medium after transfer is conveyed to the fixing device 9 in the same manner as described above to fix the image, and the transfer medium after fixing is discharged to the discharge tray 17.

  In the above configuration, the intermediate transfer medium can be used without using an intermediate transfer medium, and a tandem type direct transfer image forming apparatus can be used. In the case of this direct transfer system, the transfer medium is supported instead of the intermediate transfer medium. Using a transfer belt or the like that transports, a plurality of toner images of different colors sequentially produced on each photoreceptor 1 (1Y, 1M, 1C, 1K) by each image forming unit 10 are directly transported by the transfer belt. Alternatively, the toner may be transferred to a fixing device after being sequentially transferred to the transfer medium, and the toner is fixed by heat or the like.

[Embodiment 4]
Next, a photoconductor suitably used in the process cartridge and the image forming apparatus according to the present invention will be described.
In the photoreceptor, which is an image carrier used in the image forming apparatus of the present invention, a photosensitive layer is provided on a conductive support. The photosensitive layer is composed of a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer provided on the charge transport layer. There is a reverse layer type. In addition, a surface layer can be provided on the photosensitive layer in order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property and the like of the photoreceptor. An undercoat layer may be provided between the photosensitive layer and the conductive support. In addition, an appropriate amount of a plasticizer, an antioxidant, a leveling agent and the like can be added to each layer as necessary.

Examples of the conductive support for the photoreceptor include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation A metal oxide such as indium is deposited or sputtered on a film or cylindrical plastic or paper, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc. After forming the tube into a drum shape, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. A drum-shaped support having a diameter of 20 to 150 mm, preferably 24 to 100 mm, and more preferably 28 to 70 mm can be used. If the diameter of the drum-shaped support is less than 20 mm, it is physically difficult to arrange the charging, exposure, development, transfer, and cleaning steps around the drum. If the diameter of the drum-shaped support exceeds 150 mm, the image The forming apparatus becomes undesirably large. In particular, when the image forming apparatus is a tandem type as shown in FIG. 3, it is necessary to mount a plurality of photoconductors, and therefore the diameter is preferably 70 mm or less, and preferably 60 mm or less. Moreover, the endless nickel belt and the endless stainless steel belt disclosed in Patent Document 2 can also be used as the conductive support.

  As the undercoat layer of the photosensitive member used in the image forming apparatus of the present invention, a resin or a material mainly composed of a white pigment and a resin, a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate, etc. However, those containing a white pigment and a resin as main components are preferable. Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among them, it is most preferable to contain titanium oxide that is excellent in preventing charge injection from the conductive substrate. As the resin used for the undercoat layer, thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose, thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy, one or various kinds of these Mixtures can be exemplified. The undercoat layer may be a single layer or a plurality of layers.

  Examples of the charge generating material for the photoreceptor used in the image forming apparatus of the present invention include azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, and tetrakisazo pigments, triarylmethane dyes, thiazine dyes, and oxazines. Dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments Inorganic materials such as pigments, organic pigments and dyes such as phthalocyanine pigments, selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, and amorphous silicon can be used. It can be used alone or in combination.

  Examples of the charge transport material for the photoreceptor used in the image forming apparatus of the present invention include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, Enamine compounds, butadiene compounds, distyryl compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, triphenylmethane derivatives, etc. can do.

  The binder resin used to form the photosensitive layer of the charge generation layer and the charge transport layer is electrically insulating and is a known thermoplastic resin, thermosetting resin, photocurable resin, and photoconductive material. Suitable binder resins include, for example, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, Ethylene-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, thermoplastic resin such as polysulfone, polyethersulfone, ABS resin, phenol resin , Epoxy resin, urethane resin, melamine resin, isocyanate resin, alkyd resin, Examples thereof include a thermosetting resin such as a ricone resin, a thermosetting acrylic resin, a type of binder resin such as a photoconductive resin such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, or a mixture of various types of binder resins. In particular, it is not limited to these. However, when the charge transport layer is the outermost surface, a binder resin containing polycarbonate is used.

As antioxidant, the following are used, for example.
Monophenol compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di- t-butyl-4-hydroxyphenyl) propionate, 3-t-butyl-4-hydroxynisol and the like.

Bisphenol compounds 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 ′ -Thiobis- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol) and the like.

-High molecular phenol compound 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3 '-Bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocophenols, and the like.

Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- ( 2-octadecenyl) -5-methylhydroquinone and the like.

Organic sulfur compounds Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.

Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

  As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is about 0 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Is appropriate.

  A leveling agent may be added to the charge transport layer. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 100 parts by weight of the binder resin. 0 to 1 part by weight is suitable.

  As described above, the surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor. Examples of the surface layer include a polymer having a mechanical strength higher than that of the photosensitive layer and a polymer in which an inorganic filler is dispersed. If the surface layer has a thin film thickness, there is no problem even if it does not have the charge transport capability. However, if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, Since it is easy to cause a potential increase, it is preferable to use the above-mentioned charge transporting substance in the surface layer, or to use a polymer having a charge transporting capability for the polymer used in the surface layer. When the surface layer is provided, the mechanical strength of the photosensitive layer and the surface layer generally differs greatly, and the surface layer is worn away due to friction with the cleaning blade. It is important that the surface layer has a sufficient film thickness, and is 0.1 to 12 μm, preferably 1 to 10 μm, more preferably 2 to 8 μm. If the film thickness of the surface layer is less than 0.1 μm, it is not preferable because it is too thin and easily disappears partially due to friction with the cleaning blade, and wear of the photosensitive layer proceeds from the disappeared portion. When the film thickness of the surface layer exceeds 12 μm, the sensitivity, the post-exposure potential increase, and the residual potential increase are likely to occur. In particular, when a polymer having charge transport capability is used, the cost of the polymer having charge transport capability is low. Since it becomes high, it is not preferable.

  As the polymer used for the surface layer, polycarbonate that is transparent to the writing light at the time of image formation and excellent in insulation, mechanical strength, and adhesiveness is used. In addition, ABS resin, ACS resin, olefin- Vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin , Polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin, etc. It may be. These polymers may be thermoplastic polymers, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a curable polymer, the mechanical strength of the surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

In the surface layer, fine particles (fillers) of metal or metal oxide can be dispersed in order to increase the mechanical strength of the surface layer. Examples of the metal oxide include alumina, titanium oxide, tin oxide, potassium titanate, TiO ₂ , TiN, zinc oxide, indium oxide, and antimony oxide. In addition, fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials in these resins can be added for the purpose of improving wear resistance.

  In the above embodiments, the image carrier is described as a photoconductor. However, in the image forming apparatus according to the present invention, the image carrier primarily transfers a toner image formed on the photoconductor to perform color superposition, and further transfers. It may be an intermediate transfer medium that is used when image formation is performed by a so-called intermediate transfer method for transferring to a medium.

As the intermediate transfer medium, a medium having a volume resistance of 10 ⁵ to 10 ¹¹ Ω · cm is preferable. When the volume resistance is less than 10 ⁵ Ω · cm, when transferring the toner image from the photosensitive member onto the intermediate transfer member, so-called transfer dust may occur in which the toner image is disturbed due to discharge. If it exceeds ¹¹ Ω · cm, after transferring the toner image from the intermediate transfer body to a recording medium such as paper, the counter charge of the toner image remains on the intermediate transfer body and appears as an afterimage on the next image. There is. The surface resistance is preferably 10 ⁸ to 10 ¹³ Ω / sq. When the surface resistance is less than 10 ⁸ Ω / sq., Troubles such as a toner image being disturbed or transfer dust may occur. When it exceeds 10 ¹³ Ω / sq., Primary transfer is difficult. May be.

  As an intermediate transfer medium, for example, a metal oxide such as tin oxide or indium oxide, or conductive particles such as carbon black or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then extruded into a belt shape Alternatively, a cylindrical plastic can be used. In addition to this, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermal crosslinking reactive monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer medium on an endless belt. You can also.

  When providing a surface layer on the intermediate transfer medium, among the surface layer materials used for the above-mentioned photoreceptor surface layer, the composition excluding the charge transport material is appropriately adjusted in combination with a conductive substance, Can be used.

[Embodiment 5]
Next, a toner suitably used in the process cartridge and the image forming apparatus according to the present invention will be described.
First, the toner used in the image forming apparatus of the present invention preferably has an average circularity of 0.93 to 1.00. In the present invention, the value obtained from Equation 1 below is defined as the circularity. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.
Circularity SR = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image: (Formula 1)

When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small, so that the transferability is excellent.
Since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated.
Since there are no angular toner particles in the toner that forms the dots, when the pressure is brought into contact with the transfer medium during the transfer, the pressure is uniformly applied to the entire toner that forms the dots, and the transfer is not easily lost.
Since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the image carrier is not damaged or worn.

Next, a method for measuring the circularity will be described.
The circularity can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics.
As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured by the above apparatus with the dispersion concentration being 3000 to 10000 / μl.

The toner used in the image forming apparatus of the present invention preferably has a weight average diameter D4 of 3 to 10 μm in addition to the above circularity. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent.
When the weight average diameter D4 is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. Moreover, when the weight average diameter D4 exceeds 10 μm, it is difficult to suppress scattering of characters and lines.

Further, the toner according to the present invention preferably has a ratio (D4 / D1) of the weight average diameter D4 and the number average diameter D1 of 1.00 to 1.40. The closer the value of (D4 / D1) is to 1, the sharper the particle size distribution of the toner. Therefore, when (D4 / D1) is in the range of 1.00 to 1.40, the selective development due to the toner particle size does not occur, and the stability of the image quality is excellent.
Since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp, and fogging is suppressed. In addition, when the toner particle diameters are uniform, the latent image dots are developed so as to be densely and orderly arranged, so that the dot reproducibility is excellent.

Next, a method for measuring the particle size distribution of toner particles will be described.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.

  First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average diameter D4 and the number average diameter D1 of the toner can be obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  In addition, as such a substantially spherical toner, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of fine resin particles. A toner that undergoes crosslinking and / or elongation reaction is preferred. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

  Examples of the prepolymer comprising a modified polyester resin that can be used for toner production include a polyester prepolymer (A) having an isocyanate group, and examples of the compound that extends or crosslinks with the prepolymer include amines (B). Can be mentioned.

  Examples of the polyester prepolymer (A) having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate (3), which is a polycondensate of polyol (1) and polycarboxylic acid (2). Can be mentioned. Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferred.

  Examples of the polyol (1) include a diol (1-1) and a tri- or higher valent polyol (1-2). (1-1) alone or (1-1) and a small amount of (1-2) Mixtures are preferred. Diol (1-1) includes alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide phenol compound (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyol (1-2) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and tri- or higher valent polycarboxylic acid (2-2), and dicarboxylic acid (2-1) alone and dicarboxylic acid (2-1). And a small amount of a trivalent or higher polycarboxylic acid (2-2) mixture.
Dicarboxylic acid (2-1) includes alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms.

  Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). In addition, as polycarboxylic acid (2), you may make it react with polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.

  The ratio of the polyol (1) to the polycarboxylic acid (2) is usually 2/1 to 1/1, preferably 1. as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 5/1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates such as phenol derivatives, oximes, caprolactam And a combination of two or more of these.

  The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, preferably 4 /, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. It is. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1-B5 blocked (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester (i) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  By these reactions, the modified polyester used in the toner of the present invention, in particular, the urea-modified polyester (i) can be produced. These urea-modified polyesters (i) are produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  In the present invention, not only the polyester (i) modified with a urea bond but also the polyester (ii) not modified can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and glossiness when used in a full-color apparatus are improved, which is preferable to single use. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i) above, and preferred ones are also the same as (i). (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) and (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 1-30, preferably 5-20. By having an acid value, it tends to be negatively charged.

  In the present invention, the glass transition point (Tg) of the binder resin is usually 50 to 70 ° C., preferably 55 to 65 ° C. If it is less than 50 ° C., the blocking of the toner during high temperature storage deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners.

As the storage elastic modulus of the binder resin, the temperature (TG ′) at which 10000 dyne / cm ² is obtained at a measurement frequency of 20 Hz is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates.
As the viscosity of the binder resin, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or lower, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or higher. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

  The binder resin can be produced by the following method. The polyol (1) and the polycarboxylic acid (2) are heated to 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and the generated water is distilled off as necessary. Thus, a polyester having a hydroxyl group is obtained. Next, this is reacted with polyisocyanate (3) at 40 to 140 ° C. to obtain a prepolymer (A) having an isocyanate group. Further, the amine (B) is reacted with the prepolymer (A) having an isocyanate group at 0 to 140 ° C. to obtain a polyester modified with a urea bond.

  When the polyisocyanate (3) is reacted and when the prepolymer (A) having an isocyanate group and the amines (B) are reacted, a solvent can be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to the isocyanate (3), such as tetrahydrofuran (such as tetrahydrofuran). When polyester (ii) not modified with urea bond is used in combination, (ii) is produced by the same method as polyester having a hydroxyl group, and this is dissolved in the solution after completion of the reaction of (i) and mixed. To do.

In addition, the toner used in the present invention can be produced generally by the following method, but is not limited thereto.
The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  The toner particles may be formed by reacting a dispersion composed of a prepolymer (A) having an isocyanate group in an aqueous medium with amines (B), or using a urea-modified polyester (i) produced in advance. May be. As a method for stably forming a dispersion comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium, a toner raw material comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force. The prepolymer (A) and other toner compositions (hereinafter referred to as toner raw materials), a colorant masterbatch, a release agent, a charge control agent, an unmodified polyester resin, etc. are dispersed in an aqueous medium. It may be mixed at the time of formation, but it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, but after the particles are formed. , May be added. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion made of urea-modified polyester (i) or prepolymer (A) has a low viscosity and is easy to disperse.

  The amount of the aqueous medium used relative to 100 parts of the toner composition containing the urea-modified polyester (i) and the prepolymer (A) is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

  In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner composition is dispersed in the aqueous medium, or may be dispersed in the aqueous medium. An amine (B) may be added later to cause a reaction from the particle interface. In this case, urea-modified polyester is preferentially produced on the surface of the manufactured toner, and a concentration gradient can be provided inside the particles.

  Anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates and phosphates, alkylamines as dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water Amine salts such as salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, etc. Nonionic surfactants such as quaternary ammonium salt type cationic surfactants, fatty acid amide derivatives, polyhydric alcohol derivatives, such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl N, amphoteric surfactants such as N- dimethyl ammonium betaine and the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6 to C11). Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carboxylic acid and Metal salt, perfluoroalkyl carboxylic acid (C7 to C13) and its metal salt, perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, perfluorooctane sulfonic acid diethanolamide, N-propyl-N- (2 hydroxy ethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Is mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. , DS-102, (manufactured by Taikin Kogyo Co., Ltd.), Megafac F-ll0, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink), Xtop EF- 102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F-150 (manufactured by Neos).

  Cationic surfactants include aliphatic primary, secondary or secondary amine acids having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, benzalkonium Salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries), Mega Facks F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos).

As an inorganic compound dispersant that is hardly soluble in water, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite, and the like can also be used.
Further, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Of methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and carboxyl group Esters such as pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, pinyl pyridine, vinyl pyrrolidone, vinyl imidazole, Homopolymers or copolymers such as those having a nitrogen atom such as ethyleneimine or a heterocyclic ring thereof, polyoxyethylene, polyoxypropylene, polyethylene Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation.
When a dispersant is used, the dispersant may remain on the surface of the toner particles, but it is preferable from the charged surface of the toner that the dispersant is washed and removed after the elongation and / or crosslinking reaction.

  Furthermore, in order to lower the viscosity of the toner composition, a solvent in which the urea-modified polyester (i) or the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred, and aromatic solvents such as toluene and xylene are more preferred. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or cross-linking reaction time is selected depending on the reactivity of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. is there. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer or rotary kiln.

When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution.
In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet. Moreover, it is preferable to remove the used dispersant from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

The obtained toner powder after drying is mixed with different kinds of particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or gives mechanical impact force to the mixed powder. Thus, it is possible to prevent detachment of foreign particles from the surface of the composite particle obtained by immobilizing and fusing on the surface.
Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting the mixture into a high-speed air stream, accelerating the particles, and causing the particles or composite particles to collide with an appropriate collision plate, etc. There is. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) has been modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar, etc.

  As the colorant used in the toner, pigments and dyes that have been conventionally used as toner colorants can be used. Specifically, carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline Blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, rose bengal and the like can be used alone or in combination.

  Furthermore, if necessary, in order to give the toner particles magnetic properties, magnetic components such as iron oxides such as ferrite, magnetite and maghemite, metals such as iron, cobalt and nickel, or alloys of these with other metals. May be contained alone or in combination in the toner particles. Moreover, these components can also be used / used together as a colorant component.

The number average diameter of the colorant in the toner used in the present invention is desirably 0.5 μm or less, preferably 0.4 μm or less, more preferably 0.3 μm or less.
When the number average diameter of the colorant in the toner is larger than 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained.
A colorant having a fine particle diameter of less than 0.1 μm is sufficiently smaller than a half wavelength of visible light, and thus is considered not to adversely affect light reflection and absorption characteristics. Therefore, the colorant particles of less than 0.1 μm contribute to good color reproducibility and transparency of the OHP sheet having a fixed image. On the other hand, if there are many colorants having a particle size larger than 0.5 μm, the transmission of incident light is hindered or scattered, and the brightness and color of the projected image of the OHP sheet tend to decrease. There is.
Further, if there are many colorants having a particle size larger than 0.5 μm, the colorant is detached from the surface of the toner particles and easily causes various problems such as fogging, drum contamination, and poor cleaning. In particular, the colorant having a particle size larger than 0.7 μm is preferably 10% by number or less of the total colorant, and more preferably 5% by number or less.

Also, by mixing the colorant together with part or all of the binder resin in advance after adding a wetting liquid, the binder resin and the colorant are initially sufficiently adhered, In the toner production process, the colorant is dispersed more effectively in the toner particles, the dispersed particle diameter of the colorant is reduced, and better transparency can be obtained.
As the binder resin used for kneading in advance, the resins exemplified as the binder resin for toner can be used as they are, but are not limited thereto.

As a specific method for kneading the mixture of the binder resin and the colorant with the wetting liquid in advance, for example, the binder resin, the colorant and the wetting liquid are obtained after mixing with a blender such as a Henschel mixer. The obtained mixture is kneaded at a temperature lower than the melting temperature of the binder resin by a kneader such as a two-roll or three-roll to obtain a sample.
In addition, as the wetting liquid, a general one can be used in consideration of the solubility of the binder resin and the paintability with the colorant, but in particular, an organic solvent such as acetone, toluene, butanone, or water, It is preferable from the viewpoint of dispersibility of the colorant. Among these, the use of water is more preferable from the viewpoint of environmental considerations and maintaining the dispersion stability of the colorant in the subsequent toner production process.
According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is further improved. Get better.

In addition, as long as the configuration of the present invention is adopted, a release agent represented by wax can be contained in the toner together with the binder resin and the colorant.
Known release agents can be used, such as polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sasol wax, etc.); carbonyl group-containing wax, etc. .

  Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylene diamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearyl amide, etc.) And dialkyl ketones (such as distearyl ketone).

  Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of these release agents is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset when fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

In addition, a charge control agent may be contained in the toner as necessary in order to accelerate the toner charge amount and its rise. Here, since a color change occurs when a colored material is used as the charge control agent, a material that is colorless and close to white is preferable.
Any known charge control agent can be used. Examples include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkyls. Amide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron P-51 of a quaternary ammonium salt, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex, E-89 of a phenol condensate (above, Orient Chemical Co., Ltd.) Manufactured), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), copy charge PSY VP2038 of quaternary ammonium salt, copy blue PR of triphenylmethane derivative, Quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, boron complex LR-147 (manufactured by Nippon Carlit), quinacridone, azo pigment, other sulfonic acid groups , A polymer compound having a functional group such as a carboxyl group or a quaternary ammonium salt. It is.

In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, or may be added when directly dissolving and dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. Also good.
Further, when the toner composition is dispersed in the aqueous medium during the toner production process, resin fine particles mainly for stabilizing the dispersion may be added.

  The resin fine particles used may be any resin that can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resins, polyurethane resins, epoxy resins, polyester resins, Examples thereof include polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. As the resin fine particles, two or more of the above resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.

  The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include, but are not limited to, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like.

Further, inorganic fine particles can be preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles.
The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

  In addition, polymer fine particles, such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, methacrylate esters, acrylate copolymers, polycondensation systems such as silicone, benzoguanamine, and nylon, thermosetting Examples thereof include polymer particles made of a resin.

  Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the intermediate transfer medium include fatty acid metal salts such as zinc stearate, calcium stearate and stearic acid, such as polymethyl methacrylate fine particles, polystyrene. Examples thereof include fine polymer particles produced by soap-free emulsion polymerization of fine particles and the like. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

By using these toners, a high-quality toner image having excellent development stability can be formed as described above. However, the toner that is not transferred to the transfer medium or intermediate transfer medium by the transfer device and remains on the image carrier is difficult to remove by the cleaning device due to its fineness and good rolling properties. May end up. In order to completely remove the toner from the image carrier, it is necessary to strongly press a toner removing member such as a cleaning blade against the image carrier. Such a load not only shortens the life of the image carrier and the cleaning device, but also uses extra energy.
When the load on the image carrier is reduced, the toner and the small-diameter carrier on the image carrier are not sufficiently removed, and these damage the surface of the image carrier when passing through the cleaning device. It becomes a factor which fluctuates performance.

As described above, the image forming apparatus of the present invention has an excellent tolerance for fluctuations in the surface state of the photoreceptor, particularly the presence of a low-resistance portion, and has a configuration in which fluctuations in charging performance to the photoreceptor are highly suppressed. For this reason, when used in combination with the toner having the above-described configuration, an extremely high-quality image can be stably obtained over a long period of time.
In addition, the image forming apparatus of the present invention can be applied not only to the use of the toner having a configuration suitable for obtaining a high quality image as described above, but also to an irregular shaped toner by a pulverization method, and the life of the apparatus. Needless to say, it will be greatly extended.

As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.
Examples of general binder resins used in the toner include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and the like; styrene / p-chlorostyrene copolymers; Styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, Styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / Acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer, Styrene copolymers such as tylene / butadiene copolymers, styrene / isoprene copolymers, styrene / maleic acid copolymers; polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate, etc. Acrylic ester-based homopolymers and copolymers thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester-based polymers, polyurethane-based polymers, polyamide-based polymers, polyimide-based polymers, polyol-based polymers, Examples thereof include an epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, and the like. These can be used alone or in combination, but are not particularly limited thereto. Among these, at least one selected from styrene-acrylic copolymer resins, polyester resins, and polyol resins is more preferable from the viewpoint of electrical characteristics, cost, and the like. Furthermore, it is more preferable to use a polyester-based resin and / or a polyol-based resin as having good fixing characteristics.

  In the pulverized toner, together with these resin components, the colorant component, wax component, charge control component, and the like as described above are premixed as necessary, and then kneaded at a temperature close to the melting temperature of the resin component, and then cooled. Thereafter, a toner may be prepared through a pulverizing and classifying step, and the above-mentioned external additive components may be appropriately added and mixed as necessary.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
The manufacture of the photoreceptors 1 to 13 used in this example was performed as follows.

(Photoconductor)
An undercoat layer, a charge generation layer, a charge transport layer, and a surface layer were applied in this order on an aluminum drum (conductive support) having a diameter of 40 mm, and then dried, and a 3.6 μm undercoat layer having a thickness of about 0.00 mm. A photoreceptor comprising a 14 μm charge generation layer, a 23 μm charge transport layer, and a surface layer of about 3.5 μm was prepared. At this time, coating of the surface layer was performed by a spray method, and the others were performed by a dip coating method. Details of each layer were as follows.

[Coating liquid for undercoat layer]
・ Alkyd resin (Beccosol 1307-60-EL,
Dainippon Ink & Chemicals, Inc.) 6 parts by mass Melamine resin (Super Becamine G-821-60,
Dainippon Ink & Chemicals, Inc.) 4 parts by mass Titanium oxide ... 40 parts by mass Methyl ethyl ketone ... 200 parts by mass

[Coating liquid for charge generation layer]
・ Y-type oxo titanyl phthalocyanine pigment ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2 parts by mass ・ Polyvinyl butyral (S-REC BM-S,
Sekisui Chemical Co., Ltd.) 0.2 mass parts Tetrahydrofuran 50 mass parts

・塩化メチレン・・・・・・・・・・・・・・・・・・・・・・１００質量部 [Coating liquid for charge transport layer]
・ Bisphenol A type polycarbonate (manufactured by Teijin Limited, Panlite K1300) ・ ・ ・ ・ ・ ・ ・ ・ 10 parts by mass ・ Low molecular charge transport material represented by the following structural formula ・ ・ ・ ・ ・ ・ ・ ・ 10 Parts by mass

・ Methylene chloride ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 100 parts by mass

[Surface layer coating solution]
・ Polycarbonate ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10 parts by mass ・ Low molecular charge transport material represented by the following structural formula ・ ・ ・ ・ ・ ・7 parts by mass-Alumina fine particles (center particle size 0.30 μm) ... 6 parts by mass-Dispersing aid (by Big Chemie Japan,
BYK-P104) ······ 0.08 parts by mass · Tetrahydrofuran ·················· 700 parts by mass · Cyclohexanone ···・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 200 parts by mass

Production of the protective agent bar used was carried out as follows.
(Method for producing protective agent bar (1) (only a mixture of zinc stearate and zinc palmitate))
The powder of the mixture of zinc stearate and zinc palmitate is put into an aluminum mold having an inner dimension of 8 mm × 350 mm, pressed with a hydraulic press machine, compressed to 95% of the true specific gravity, and 7 mm thick. A protective agent bar was prepared.
The produced protective agent bar was cut at both ends in the longitudinal direction, and the bottom surface was cut to produce a protective agent bar (1) of 7 mm × 8 mm × 310 mm. A double-sided tape was affixed to the bottom of the protective agent bar (1) and fixed to a metal support.

(Production method of protective agent bars (2) and (3) (containing BN))
A mixture of zinc stearate and zinc palmitate is mixed and stirred so that the BN content is 3% by weight, and the powder after stirring is placed in an aluminum mold having an inner dimension of 8 mm × 350 mm, Pressure was applied with a press machine and compressed to 95% of the true specific gravity to prepare a protective agent bar having a thickness of 7 mm. (However, the mixing ratio of zinc stearate and zinc palmitate in the protective agent bars (2) and (3) is changed for each.)
The produced protective agent bar was cut at both ends in the longitudinal direction, and the bottom surface was cut to produce a protective agent bar of 7 mm × 8 mm × 310 mm. Double-sided tape was affixed to the bottom of the protective agent bar and fixed to a metal support.

(Method for producing protective agent bars (4) and (5) (containing BN and alumina))
In a mixture of zinc stearate and zinc palmitate, each powder of BN and spherical alumina particles having a particle size of 0.3 μm is mixed and stirred, and the powder after stirring is put into an aluminum mold having an inner size of 8 mm × 350 mm. Then, pressure was applied with a hydraulic press machine and compressed to 95% of the true specific gravity to produce a protective agent bar having a thickness of 7 mm. (Similarly, the mixing ratio of the zinc stearate and the zinc palmitate in the protective bars (4) and (5) is changed for each.)
The produced protective agent bar was cut at both ends in the longitudinal direction, and the bottom surface was cut to produce a protective agent bar of 7 mm × 8 mm × 310 mm. Double-sided tape was affixed to the bottom of the protective agent bar and fixed to a metal support.

  Table 1 shows the mixing ratio (weight ratio) of zinc stearate and zinc palmitate, the mixing ratio of metal soap (zinc stearate and zinc palmitate) and BN (weight ratio), and the ratio of alumina to metal soap (weight ratio). Indicates.

The blade used was a urethane blade.
After the photoconductor was manufactured, the following photoconductor protective sheet was mounted. In this example, a black light-shielding paper containing carbon black was used for the photosensitive member protection sheet. The photosensitive member protective sheet was left attached to the photosensitive member for one day or longer. When the evaluation was performed, the photosensitive member protective sheet was removed from the photosensitive member, and the photosensitive member was attached to the apparatus.

(Photosensitive members 1, 2, 6, 10, 11: BN)
A fine cloth wrapped with BN was lightly struck, and BN powder was adhered to the surface of the photosensitive member on the photosensitive member side, and mounted on the photosensitive members 1, 2, 6, 10, and 11.

(Photoconductors 3-5, 12, 13: a mixture of BN, zinc stearate, and zinc palmitate)
Stir well the mixture of BN, zinc stearate and zinc palmitate, press once with hydraulic press machine, press the molded bar (protective agent bars (2) and (3) are the same production method) The powder (lubricant mixture) is pulverized into powder, wrapped in a fine cloth, and the fine cloth is lightly struck against the photoreceptor side surface of the protective sheet for the photoreceptor. , 13 attached.
After pressing once as described above and analyzing the pulverized powder by ICP emission spectroscopic analysis, the powder was attached to the surface of the photosensitive member on the protective sheet of the photosensitive member attached to the photosensitive member 3, 4, 5, 12, 13. The ratio of the mixture of zinc stearate and zinc palmitate to BN was, in order, metal soap / BN = 70/30, 40/60, 91/9, 40/60, and 40/60.

(Photoreceptor 7: No application)
The photoconductor 7 was mounted as it was without attaching anything to the protective sheet for the photoconductor.

(Photoreceptor 8: Metal soap)
Lightly tap a fine cloth wrapped with metal soap (pulverized from the protective agent bar (1)) against the surface of the photoconductor protective sheet and attach the protective sheet to the photoconductor 8 did.

(Photoreceptor 9: PMMA)
A fine cloth wrapped with PMMA (polymethyl methacrylate) was lightly struck against the surface of the photoconductor protective sheet, and the protective sheet was attached to the photoconductor 9.

  Table 2 shows the mixing ratio (weight ratio) of the substance applied to the black paper, metal soap and BN.

  For the evaluation, an image forming apparatus (imagio MPC4500 (tandem color image forming apparatus, manufactured by Ricoh)) having a plurality of image forming units (process cartridges) each having a protective agent coating apparatus as shown in FIG. The installed protective agent blade was replaced with an obtuse angle blade (counter) for evaluation, and the linear velocity of the photosensitive member was 125 mm / second, and a DC voltage of −600 V was applied between the photosensitive member and the charging roller. Evaluation was performed by applying an alternating voltage having a frequency of 1450 Hz and an amplitude of 1100 V. All evaluations were performed in a low temperature and low humidity (room temperature 15 ° C., humidity 30%) environment.

An ISO test chart (ISO / IEC JTC 1 / SC 28 homepage http://www.iso.org/jtc1/sc28) was used as an output chart for evaluation. After outputting 5000 ISO test charts, for the blades after image output of Examples 1 to 10 and Comparative Examples 2 and 3, the powder adhering to the blades was carefully scraped with a spatula, and ICP emission spectroscopic analysis and FR-IR were performed. It was used to evaluate the presence of BN or metal soap or PMMA on the blade. In addition, in order to perform ICP emission spectroscopic analysis, since the amount of powder to be scraped was required to be a certain amount or more, image output under the same conditions was performed a plurality of times, and an analysis sample for ICP emission spectroscopic analysis was collected. Similarly, for FR-IR analysis, image output under the same conditions is performed a plurality of times, and KBr powder is sprayed on the blade used for each image output, and the dusted KBr is collected again, and all powder is collected. They were collected to make tablets (analytical samples) and analyzed. (The presence or absence of BN was determined by the peak of IR in the presence of B, metal soap and PMMA in ICP emission analysis.)
The evaluation results are shown in Table 3.

[Example 1]
Using the photoreceptors shown in Table 3, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 2]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 3]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

  When the 10000th output image in total and the 10000th output image in Examples 1 and 2 were compared with a microscope, the output images in Examples 1 and 3 had neatly arranged dots. In the image of Example 2, the dot density varied somewhat. Again, the images of Examples 1, 2 and Example 3 were compared visually, but no significant difference was found in the three images visually.

[Example 4]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 5]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 6]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

  When the total output image of 10,000 sheets and the output image of the total 10,000 sheets of Examples 4, 5, and 6 were compared by microscopic observation, the output image of Example 4 had neatly arranged dots. In the image of Example 5, the dot density varied somewhat. In the image of Example 6, the dot size was slightly widened. Again, the images of Examples 4 to 6 were compared visually, but no significant difference was observed in the three images visually.

  Furthermore, when a total of 5000 output images of Examples 1 to 6 were observed through a microscope and compared, the output images of Examples 1 to 5 had neatly arranged dots, but the image of Example 6 was The dot size was slightly widened. Again, the images of Examples 1 to 6 were compared visually, but no significant difference was found in the six images visually.

[Example 7]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 8]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 9]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Example 10]
Using the photoreceptors shown in Table 3, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

  When the 5000th and 10000th output images in Examples 7 to 10 were compared by microscopic observation, the dots were neatly arranged in all the output images.

[Comparative Example 1]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. As a result of visual evaluation of the 10,000th output image in total, a high-quality image was retained.

[Comparative Example 2]
Using the photoreceptors shown in Table 3, 5000 ISO test charts were output. When a visual evaluation was performed on the 5000th output image, a faint black belt was observed. Subsequently, 5000 ISO test charts were output. When visual evaluation was performed on the 10,000th total output image, a black belt was seen in the output image as in the 5000th image.

[Comparative Example 3]
Using the photoconductor, the protective agent bar, the brush, and the spring pressure condition in which the protective agent is pressed against the brush, 5000 ISO test charts were output. When visual evaluation was performed on the 5000th output image, a high-quality image was retained. Subsequently, 5000 ISO test charts were output. When visual evaluation was performed on the total output image of the 10,000th sheet, fine streak defects and a thin background stain were observed in a portion (background portion) where there was no printing. Also, the image was rough.

  Further, the 5000th output image of Comparative Examples 1 and 3 and the 10000th output image of Comparative Example 1 were compared by observing under a microscope, and compared with the output images of Examples 1 to 4. The 5000th image and the 10,000th image in Example 1 have different dot densities, and the 5000th image in Comparative Example 3 has a different dot density. Was seen more on other output images. Again, the images of Comparative Examples 1 and 3 and Examples 1 to 4 were compared visually, but no significant difference was found in the seven images visually.

  Subsequently, ISO test chart output of a further 40000 sheets, a total of 50000 sheets, was performed under the conditions of Examples 5 and 6 and Comparative Example 1, and visual evaluation was performed on the output image of the 50000 sheets. The output image under the condition (2) was a high-quality image, but the output image under the condition of Comparative Example 1 showed slight streak defects.

DESCRIPTION OF SYMBOLS 1 Photoconductor 10 Image forming part 11 Process cartridge 12 Secondary transfer device 13 Conveyance device 14 Fixing device 15 Conveyance device 16 Discharge roller 17 Discharge tray 2 Protective agent application device 21 Protective agent bar 22 Protective agent supply material 22a Brush 22b Support Body 23 pressing force applying mechanism 24 protective layer forming mechanism 24a blade-like member 24b pressing member 24c blade support 25 protective agent bar support guide 3 charging device 4 cleaning device 41 cleaning member 42 cleaning pressing mechanism 5 developing device 51 developing roller 52 Developer agitating and conveying member 53 Developer agitating and conveying member 6 Primary transfer device 7 Transfer medium 8 Latent image forming device 9 Belt cleaning device 100 Image forming device 110 Image forming device main body (printer unit)
120 Document reading unit (scanner unit)
130 Automatic document feeder (ADF)
200 Paper Feed Unit 201a Paper Feed Cassette 201b Paper Feed Cassette 201c Paper Feed Cassette 201d Paper Feed Cassette 202 Paper Feed Roller 203 Separation Roller 204 Carrying Roller 205 Carrying Roller 206 Carrying Roller 207 Registration Roller 210 Double-sided Carrying Device L Laser Light

JP 2008-134467 A Japanese Patent Publication No. 52-036016

Claims (14)

A photoreceptor,
Charging means for charging the photoreceptor;
Latent image forming means for forming a latent image on the surface of the charged photoreceptor;
Developing means for developing a latent image formed on the surface of the photoreceptor with a developer containing toner to form a toner image;
Transfer means for transferring a toner image formed on the surface of the photoreceptor to a transfer target;
An image forming apparatus including a cleaning unit that removes residual toner on the surface of the photoreceptor after transfer,
As the photosensitive member, a photosensitive member having BN attached to the surface obtained by removing the protective sheet after being covered with the protective sheet having BN attached to the surface on the photosensitive member side is mounted. Image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the protective sheet for the photosensitive member has a mixture of metal soap and BN attached to the surface on the photosensitive member side.   3. The image forming apparatus according to claim 2, wherein the mixing ratio of the metal soap and BN adhered to the surface of the photosensitive member protective sheet is BN of 10% or more by weight.   The image forming apparatus according to claim 1, further comprising means for supplying metal soap as a protective agent to the photoconductor. BN is contained in the protective agent supplied to the photoconductor,
The image forming apparatus according to claim 4, wherein a mixing ratio of the metal soap and BN is a weight ratio, and BN is 30% or less.   6. The image forming apparatus according to claim 2, wherein the metal soap is a mixture of zinc palmitate and zinc stearate.   The image forming apparatus according to claim 5, wherein the protective agent supplied to the photosensitive member further contains alumina in addition to metal soap and BN.   The image forming apparatus according to claim 1, further comprising a blade as means for supplying a protective agent separately from the cleaning means.   9. The image forming apparatus according to claim 8, wherein BN or a mixture of metal soap and BN is attached to the blade, which is a means for supplying the protective agent, in a state before the start of use.   The image forming apparatus according to claim 8, wherein a blade, which is a means for supplying the protective agent, is in contact with the photoconductor at an angle similar to a counter system.   The image forming apparatus according to claim 8, wherein the blade serving as the means for supplying the protective agent is an obtuse angle blade. Having charging means for charging the photoreceptor;
The charging method of the photoconductor by the charging means is a contact method or a proximity method,
The image forming apparatus according to claim 1, wherein the charging unit performs AC charging in which an AC voltage is superimposed on a DC voltage.   The image forming apparatus according to claim 1, wherein a filler is dispersed in an outermost surface layer of the photoconductor.   A photosensitive member for use in the image forming apparatus according to any one of claims 1 to 13, and a developing device that develops at least a latent image on the photosensitive member with a developer are integrated and detachable from the image forming apparatus. A process cartridge configured as described above, wherein the photosensitive member having the BN adhered to the surface is mounted by removing the protective sheet after being covered by the protective sheet having the BN adhered to the surface on the photosensitive member side. Process cartridge characterized by being made.

Images