JP2015118119A - Developing roller, developing apparatus, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller configured to form a high-quality image stably.SOLUTION: A developing roller 110 includes: a first oblique groove 201 which spirally continues and is inclined with respect to a peripheral direction of the developing roller 110 and a rotation axis direction of the developing roller 110; and a second oblique groove 202 which is inclined with respect to the peripheral direction and the rotation axis direction and continues spirally so as to intersect the first oblique groove 201. An average groove depth d1 of the first oblique groove 201 is larger than an average groove depth d2 of the second oblique groove 202. An average groove width of the first oblique groove 201 is smaller than an average groove width of the second oblique groove 202.

Description

  The present invention relates to a developing roller, a developing device including the developing roller, a process cartridge including the developing device, and an image forming apparatus including the developing device or the process cartridge.

  Here, the image forming apparatus forms an image on a recording material (recording medium) using an electrophotographic image forming method, and includes at least a copying machine, a printer, a facsimile apparatus, a word processor, and a multifunction machine of these. It is. The developing device is a device for visualizing an electrostatic image on an image carrier such as an electrophotographic photosensitive member using a developer. In addition, the process cartridge is one in which an electrophotographic photosensitive member and at least a developing unit serving as a process unit that acts on the electrophotographic photosensitive member are integrated and detachable from the main body of the image forming apparatus.

  In an image forming apparatus using an electrophotographic method, generally, an electrostatic image is formed by selectively exposing the outer peripheral surface of a photosensitive drum as a uniformly charged electrophotographic photosensitive member. A toner image is visualized by the toner of the developer carried on a developer carrying member such as a developing roller. Then, the toner image formed on the photosensitive drum is transferred to a recording material, and further, the toner image is fixed on the recording material by applying heat or pressure to the toner image transferred onto the recording material. I do.

  In such an image forming apparatus, in order to stably form a high-precision image, it is necessary to make the amount of toner on the developer carrier uniform and optimal, for example, for conventional coating A proposal has been made regarding a developing roller in which a rod is improved and a U-shaped groove and a V-shaped groove having different groove depths are provided on the outer peripheral surface (see Patent Document 1).

  In this case, the amount of toner on the developer carrying member is adjusted to a uniform and optimum amount by the grooves formed regularly on the outer peripheral portion of the developer carrying member, and the shape of the groove portion is specified, whereby the toner from the groove portion is specified. Is easily removed, and a certain degree of effect is achieved in making the image density uniform. However, while it is easy for the toner to come out of the groove, the toner carrying capability of the developing roller itself is reduced, so that the toner contamination in the non-image area (background) due to toner scattering or toner charging failure during image formation New problems such as this have arisen.

  On the other hand, for the purpose of improving the performance of a conventionally developed sandblasted developing roller, a developing roller having an irregular surface regularly arranged on the outer peripheral surface has been studied. For example, a spiral first groove and a second groove (hereinafter referred to as “inclined grooves”) that are inclined with respect to the direction of the rotation axis and the circumferential direction and are arranged at equal pitches in the direction of the rotation axis. Has also been proposed (see Patent Document 2), which uses a developing roller having a grid-like uneven surface.

  Because the surface shape of the sandblasted developing roller is irregular / non-uniform, there is a difference in the charged state of the toner and the transport amount, toner scattering, image background contamination, and toner filming. However, by using a developing roller having a grid-like concavo-convex surface as described above, it is possible to promote the rolling of the toner particles, improve the transport amount of the toner particles and the charged state, and solve these problems. It has been solved to some extent.

  However, as a result of studies by the present inventors, non-magnetic one-component development supplied on the developing roller by bringing a developer regulating member having a blade-like elastic contact member into contact with the outer peripheral surface of the developing roller described above. When the layer thickness of the agent is regulated, the toner particles are packed in the inclined groove on the contact surface between the developing roller and the regulating blade, and the above effects are limited. Further, when image formation is repeated many times, in addition to the above-mentioned problems, there are problems in image defects due to poor charging of toner particles and matching with image forming systems, leaving room for improvement. It was.

  The reason for this is not necessarily clear, but non-magnetic one-component developers receive external force in addition to the rotational force of the developing roller, unlike magnetic one-component developers having magnetism or two-component developers using magnetic carriers. Therefore, when the developing roller rotates, the developer roller is simply transported according to the movement of the developing roller surface, and is pushed into the inclined groove by the pressing of the developer regulating member when passing through the contact portion of the developer regulating member. I think that it may tend to be packed very easily.

  Further, as a result of the toner particles being packed in the inclined grooves, the pitch of the inclined grooves in the direction of the rotation axis of the developing roller is larger than the axial pitch of the dot-like latent images partitioned in a lattice pattern on the photosensitive drum. In order to cope with the high image quality of the image, it is necessary to finely process the surface on the developing roller according to the resolution of the latent image.

  Furthermore, in the study by the present inventors, when the developing roller as described above is used, in addition to the above problems, the ability to block air blowing from the inside of the developing device caused by the rotation of the developing roller is reduced. It has been found that it has a potential problem due to.

  That is, in the contact portion with the developer regulating member, in order to form a gap that allows the inside and outside of the developing device to communicate with each other, the toner particles packed in the inclined groove are blown away by the air from the inside of the developing device, As a result, a phenomenon such as vertical streak unevenness occurs on the surface of the photosensitive drum. In a remarkable case, it also appears as toner stains on the image, leading to deterioration in utilization efficiency of the developer and image quality.

  By the way, in each of the first inclined groove and the second inclined groove as described above, the first concave portion and the second concave portion whose groove depth is shallower than the first concave portion are provided downstream in the rotation direction of the developing roller. There has also been a proposal in which a multi-step groove structure is provided so as to partially overlap with the toner, and the rolling state of the toner particles and the escape from the developing roller are improved (see Patent Document 3).

  In this case, although the packing of the toner particles is relaxed, the volume of the convex portion is relatively reduced by the amount of the second concave portion, so that the regulating force at the contact portion between the developing roller and the developer regulating member is reduced. Becomes weak, and the ability to impart triboelectric charge to the toner particles decreases. As a result, the toner particles that have been easily removed from the inclined groove can easily reach the surface of the photosensitive drum on the air blown out from the developing device.

  Further, since the second recess has to be additionally processed so as to partially overlap the first recess, not only the productivity of the developing roller is significantly reduced, but also in the contact portion with the developer regulating member. Measures against wear and tear are necessary, and new issues are being created for practical use.

  On the other hand, there has also been proposed a developing roller in which a groove step portion is provided in the groove by intersecting inclined grooves having different groove depths (see Patent Document 4). In this case, the external additive having the maximum particle size used in the toner is used so that the groove step portion does not interfere with the rolling of the toner, and the toner step over the groove step portion is promoted. We are trying to improve the chargeability.

  However, in order to exhibit the effects as described above, (1) the surface roughness of the groove bottom portion of the developing roller and the fluctuation width of the toner particle diameter are made smaller than the maximum particle diameter of the external additive. Although methods such as using an external additive exhibiting a particle size large enough to absorb the surface roughness of the groove bottom portion and the toner particle size fluctuation are conceivable, both are difficult to implement and substantially Such issues remain unresolved.

JP 2006-259384 A JP 2007-121947 A Japanese Patent Laid-Open No. 2007-140082 JP 2010-139717 A

  SUMMARY An advantage of some aspects of the invention is that it provides a developing roller, a developing device, a process cartridge, and an image forming apparatus capable of stably providing a high-quality image. To do.

  Further, even when image formation is repeated many times in various use environments, a developing roller, a developing device, a process cartridge, and an image that can prevent an expected image quality deterioration and image defect in advance. An object is to provide a forming apparatus.

  One embodiment of the present invention is a developing roller carrying a developer on its outer peripheral surface, and is formed on the outer peripheral surface in a direction inclined with respect to the circumferential direction of the developing roller and the direction of the rotation axis of the developing roller. A first inclined groove that is continuous in a spiral shape, and a second inclined groove that is inclined with respect to the circumferential direction and the direction of the rotation axis and that is formed so as to intersect the first inclined groove. The average groove depth of the first inclined groove is deeper than the average groove depth of the second inclined groove, and the average groove width of the first inclined groove is the average groove width of the second inclined groove. Narrower than.

  According to the developing roller of the present invention, the first inclined groove and the second inclined groove having different groove depths and groove widths are arranged on the outer peripheral surface of the developing roller, and the regular shape formed by intersecting them is formed. A provided surface is provided. The developing roller having such a surface can maintain a constant charge amount and carrying amount of toner particles of the developing roller, and can provide toner particles with a suitable charge amount distribution and packing state during development. Become. Therefore, according to the developing roller, a high-quality image can be stably provided.

  Further, the outer circumferential surface is provided with a convex portion sandwiched between the first inclined grooves and sandwiched between the second inclined grooves, and the space volume of the first inclined grooves existing between the adjacent convex portions. It is preferable that the ratio (B / A) of the spatial volume (B) of the second inclined groove existing between the adjacent convex portions with respect to (A) is 0.9 or more and 4.0 or less. According to such a configuration, it is possible to carry the developer in a state suitable for development, and it is possible to preferably control the air blowing state from the inside of the developing device.

  The average groove interval of the first inclined grooves is preferably equal to the average groove interval of the second inclined grooves. According to such a configuration, the contact state with other contact members is preferable, and the self-cleaning performance and the wear state between components can be appropriately maintained.

  The developer suitable for the present invention is a one-component developer including at least a binder resin, a colorant, a release material, and an inorganic fine powder. The average groove depth of the first inclined groove is the It is preferably 105% or more and 190% or less of the weight average particle diameter (D4). According to such a configuration, since the charge imparting ability to the developer is further improved, the charge imparted state of the developer should be made suitable without including a charge control agent in the toner particles. I can do it.

  Further, it is preferable that the inorganic fine powder contains at least a silicone oil-treated inorganic fine powder having a number average particle diameter of 35 nm or more and 65 nm or less because matching with an image forming apparatus is improved.

  In addition, it is preferable that the inorganic fine powder contains at least a hydrophobized inorganic fine powder having a number average particle diameter of 70 nm or more and 200 nm or less because matching with an image forming apparatus is improved.

  According to another aspect of the present invention, a developer carrier that is rotatably disposed and carries a developer and a developer carrier that is disposed so as to abut on the outer peripheral surface of the developer carrier and is supplied onto the developer carrier. And a developer regulating member that regulates the layer thickness of the developed developer, the outer circumferential surface of the developer carrying member having a circumferential direction of the developer carrying member and a direction of the rotation axis of the developer carrying member A first inclined groove formed in a direction inclined with respect to the spiral, and a spiral formed so as to be inclined with respect to the circumferential direction and the direction of the rotation axis and intersect the first inclined groove. And an average groove depth of the first inclined groove is larger than an average groove depth of the second inclined groove, and an average groove width of the first inclined groove is: It is smaller than the average groove width of the second inclined groove.

  This developing device has a regular shape formed by arranging a first inclined groove and a second inclined groove having different groove depths and groove widths on the outer peripheral surface of the developer carrying member and intersecting them. A surface is provided. A development carrier having such a surface can maintain a constant charge amount and carrying amount of toner particles on the development carrier, and can provide toner particles with a suitable charge amount distribution and packing state during development. It becomes possible. Therefore, according to the developing device, a high-quality image can be stably provided.

  Further, the outer circumferential surface is provided with a convex portion sandwiched between the first inclined grooves and sandwiched between the second inclined grooves, and the space volume of the first inclined grooves existing between the adjacent convex portions. It is preferable that the ratio (B / A) of the spatial volume (B) of the second inclined groove existing between the adjacent convex portions with respect to (A) is 0.9 or more and 4.0 or less. According to such a configuration, it is possible to carry the developer in a state suitable for development, and it is possible to preferably control the air blowing state from the inside of the developing device.

  The average groove interval of the first inclined grooves is preferably equal to the average groove interval of the second inclined grooves. According to such a configuration, the contact state with other contact members is preferable, and the self-cleaning performance and the wear state between components can be appropriately maintained.

  The developer is a non-magnetic one-component developer containing at least a binder resin, a colorant, a release material, and an inorganic fine powder, and the average groove depth of the first inclined groove is a weight average particle of the developer. It is preferably 105% or more and 190% or less of the diameter (D4). According to such a configuration, since the charge imparting ability to the developer is further improved, the charge imparted state of the developer should be made suitable without including a charge control agent in the toner particles. I can do it.

  Further, it is preferable that the inorganic fine powder contains at least a silicone oil-treated inorganic fine powder having a number average particle diameter of 35 nm or more and 65 nm or less because matching with an image forming apparatus is improved.

  In addition, it is preferable that the inorganic fine powder contains at least the hydrophobized inorganic fine powder having a number average particle size of 70 nm or more and 200 nm because the above-described effects can be maintained.

  The developer regulating member includes an elastic contact body having an end portion extending in the width direction parallel to the rotation axis of the developer carrier. According to such a configuration, the developer having a predetermined layer thickness can be held in the first inclined groove and the second inclined groove.

  At this time, the surface hardness ratio of the contact portion of the developer regulating member with respect to the developer carrying member is preferably 0.20 or more and less than 1.00. According to this configuration, since filming of the toner can be prevented, not only the charged state of the toner particles but also the supported state of the toner particles can be maintained in the best state. As a result, for example, the occurrence of vertical stripe-shaped image density unevenness is suppressed, and deterioration / fluctuation of image density, toner contamination in a non-image area corresponding to the print background, fine line reproducibility, color tone, etc. are minimized. Therefore, it is possible to provide an excellent developing device capable of achieving the above.

  According to another aspect of the present invention, there is provided a process cartridge including an electrostatic latent image carrier and the developing device integrated with the electrostatic latent image carrier. Since this process cartridge is equipped with the above developing device, the charge amount and the carry amount of the toner particles of the developer carrying member can be kept constant, and the charge amount distribution and the packing state suitable for the toner particles during the development can be maintained. Can be provided. Therefore, according to the developing device including the developing roller, it is possible to stably provide a high-quality image.

  Another aspect of the present invention is an image forming apparatus including the developing device or the process cartridge. Since the image forming apparatus includes the developing device or the process cartridge, the charge amount and the carry amount of the toner particles on the developer carrier can be maintained constant, and the charge amount suitable for the toner particles during development can be maintained. Distribution and packing status can be provided. Therefore, according to the developing device including the developing roller, it is possible to stably provide a high-quality image.

  According to the developing roller, the developing device, the process cartridge, and the image forming apparatus of the present invention, the above-mentioned problems that have been pointed out or potentially existed are solved, and high-quality images are stably provided. be able to.

  That is, it is excellent in image density and fine line reproducibility, and it is possible to prevent toner stains in the non-image area (background) and image density unevenness in the form of vertical stripes. In addition, it is possible to make the regulated state of the developer the best, and it is possible to prevent unnecessary toner scattering on the photosensitive drum and toner sticking to the surface of the developing roller. This can contribute to stable operation of the image forming apparatus.

Sectional drawing which shows schematic structure of the image development apparatus concerning this embodiment. Schematic explanatory drawing of the developer carrying surface provided on the outer peripheral surface of the developing roller according to the present invention Explanatory drawing schematically showing the state of the gap generated when the developer regulating member comes into contact with a conventional developing roller having a grid-like uneven surface Explanatory drawing which showed typically the mode of the space | gap produced when a developer control member contact | abuts with respect to the developing roller which concerns on this invention. Explanatory drawing of the space volume (A) and space volume (B) which are defined on the 1st inclination groove | channel and 2nd inclination groove | channel on the developer carrying surface of the developing roller which concerns on this invention Explanatory drawing of the convex part height on the developer carrying surface of the developing roller which concerns on this invention Explanatory drawing of the groove depth of the inclined groove on the developer carrying surface of the developing roller according to the present invention Explanatory drawing which shows an example of the manufacturing method of the developing roller which concerns on this invention Explanatory drawing of protruding amount of developer regulating member

  Hereinafter, exemplary embodiments suitable for the present invention will be described in detail. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be changed as appropriate according to the configuration of the apparatus to which the present invention is applied and various conditions. It is not intended to limit the scope of the invention to the following embodiments. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  The present invention relates to a developing roller, a developing device, a process cartridge, and an image for use in a copying machine, a printer, a facsimile machine, a word processor, and a multi-function machine for forming an image on a recording material (recording medium) using an electrophotographic system. The present invention relates to a forming apparatus.

  First, an image forming apparatus and an image forming method using the image forming apparatus will be described.

<Regarding Image Forming Apparatus and Image Forming Method>
The image forming method according to the present embodiment includes at least a charging step in which a voltage is applied to the charging member from the outside to charge the electrostatic latent image carrier, and the electrostatic latent image on the charged electrostatic latent image carrier. A latent image forming step for forming the electrostatic image, a developing step for developing the electrostatic image with toner as a developer to form a toner image on the electrostatic latent image carrier, and a toner image on the electrostatic latent image carrier. The image forming apparatus includes a transfer process for transferring to a transfer material and a fixing process for heating and fixing a toner image on the transfer material. In addition to the above-described steps, for example, a cleaning step for removing residuals such as toner remaining on the surface of the electrostatic latent image carrier may be further provided.

  Hereinafter, an image forming apparatus using a one-component developing method will be described as an example of the image forming apparatus according to the present embodiment.

  In an image forming apparatus, a charging unit that is a charging unit that charges the surface of an electrophotographic photosensitive member and a charged electrophotographic photosensitive member are exposed around the electrophotographic photosensitive member, and an electrostatic latent image is exposed according to image information. A latent image forming unit that forms a toner image, a developing unit that is a developing unit that develops an electrostatic latent image with toner to form a toner image, and a toner image formed on the surface of the electrophotographic photosensitive member. A transfer portion that is a transfer means for transferring to the surface of the transfer body and a cleaning portion that is a cleaning means for removing the toner remaining on the surface of the electrophotographic photosensitive member after transfer are arranged in this order.

  In addition, a fixing unit that is a fixing unit that fixes the toner image transferred to the transfer target is disposed on the transfer unit side of the transfer target in the transfer unit.

  The operation of the image forming apparatus according to this embodiment will be described.

  First, the surface of the electrophotographic photosensitive member is uniformly charged by the charging unit (charging process). Next, light is irradiated onto the surface of the electrophotographic photosensitive member by the exposure unit, and the charged charges in the irradiated portion are removed, and an electrostatic charge image (electrostatic latent image) is formed according to the image information. (Latent image forming step). Thereafter, the electrostatic charge image is developed by the developing unit, and a toner image is formed on the surface of the electrophotographic photosensitive member (developing step).

  For example, consider a digital electrophotographic copying machine that uses an organic photoconductor as an electrophotographic photoconductor and uses a laser beam as an exposure unit. In this case, the surface of the electrophotographic photosensitive member is negatively charged by the charging unit, a digital latent image is formed in a dot shape by the laser beam light, and toner can be applied by the developing unit to the portion irradiated with the laser beam light. Visualized.

  Subsequently, a transfer body such as paper is superimposed on the toner image at the transfer section, and a charge having a polarity opposite to that of the toner is applied to the transfer body from the back side of the transfer body, and the toner image is transferred by electrostatic force. It is transferred to the body (transfer process). The transferred toner image is subjected to heat and pressure by a fixing member in a fixing unit, and is fused and fixed to a transfer target (fixing step).

  On the other hand, the toner remaining on the surface of the electrophotographic photosensitive member without being transferred is removed by a cleaning unit (cleaning step). One cycle is completed in a series of processes from charging to cleaning.

  Note that the toner image may be transferred to a transfer target via a transfer member such as an intermediate transfer member.

  Hereinafter, a charging unit, an electrostatic latent image carrier, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a fixing unit in the image forming apparatus will be described.

[Charging means]
As the charging unit as the charging means, for example, a charger using corona discharge, a conductive or semiconductive charging roll, or the like can be used. A contact-type charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member or may apply an alternating current superimposed thereon. By such a charging unit, the surface of the electrophotographic photosensitive member is charged by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be further provided.

[Electrostatic latent image carrier]
The electrostatic latent image carrier has a function of forming at least a latent image (electrostatic charge image). As the electrostatic latent image carrier, an electrophotographic photosensitive member is preferably exemplified. An electrophotographic photoreceptor has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer, a charge generation layer containing a charge generation material, and a photosensitive layer containing a charge transport layer containing a charge transport material are formed in this order, if necessary. It is. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single layer type photoreceptor included in the above layer may be used, but a laminated type photoreceptor is preferred. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used without being limited to the organic photoreceptor.

[Exposure means]
There are no particular limitations on the exposure unit that is the exposure means, and for example, an optical system device that can expose a light source such as a semiconductor laser beam, LED light, or liquid crystal shutter light to the surface of the electrostatic latent image carrier in a desired image-like manner. Etc.

[Development means]
The developing unit, which is a developing unit, includes at least a developer carrier, a developer (toner), and a developer regulating member, and a developer supply for supplying the developer to the developer carrier as necessary. It has a member and a stirring conveyance member. The developer carrying member supplies the developer to the electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member. For example, the developer carrying member is a cylinder or cylinder made of a nonmagnetic metal or a polymer material. It is a shaped member. The developer carrying member is rotatably installed so as to face the electrophotographic photosensitive member, and is provided with a developing bias applying unit that applies a developing bias.

  Further, a developer regulating member is provided on the upstream side in the rotation direction of the developer carrier with reference to the position where the developer carrier and the electrophotographic photosensitive member face each other. The developer regulating member is a member that equalizes the layer thickness of the developer carried on the peripheral surface of the developer carrying member, and can be constituted by, for example, a metal blade.

  When the developer is a non-magnetic one-component toner, the developer conveyed by the agitating / conveying member or the like is supplied directly and / or to the surface of the developer carrying member by the developer supply member. A predetermined developing bias is applied between the developer carrying member and the electrophotographic photosensitive member, and the developer on the developer carrying member flies onto the electrophotographic photosensitive member in accordance with the electrostatic latent image, and toner It becomes an image (visible image).

[Transfer means]
Examples of the transfer unit that is a transfer unit include a transfer unit that applies a charge having a reverse polarity to the toner from the back side of the transfer target, and transfers the toner image to the transfer target by electrostatic force, or the transfer target. A transfer roll and a transfer roll pressing device using a conductive or semiconductive roll that directly contacts and transfers to the surface of the film via a transfer medium can be used. A direct current may be applied to the transfer roll as a transfer current applied to the electrostatic latent image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll can be arbitrarily set according to the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed, and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of transferring directly to a transfer medium such as paper or a method of transferring to a transfer medium via an intermediate transfer member may be used.

  A known intermediate transfer member can be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

[Cleaning means]
The cleaning unit, which is a cleaning means, may be selected as appropriate as long as it cleans the residual toner on the electrostatic latent image carrier, such as a blade cleaning method, a brush cleaning method, or a roll cleaning method. . Among these, it is preferable to use a cleaning blade having elasticity.

[Fixing means]
The fixing unit, which is a fixing unit (image fixing device), fixes a toner image transferred to a transfer medium by heating, pressing, or heating and pressing, and includes a roller-like or belt-like fixing member. It is.

  The image forming apparatus as described above can form an image on a recording material (eg, recording paper, plastic sheet, etc.) according to the image information, and the image information is read by an image connected to the image forming apparatus. It is input from a host device such as a personal computer that is communicably connected to the apparatus or the image forming apparatus main body.

  Next, the developing device that is the developing unit of the image forming apparatus as described above will be described in more detail.

[Description of developing device]
FIG. 1 is a cross-sectional view showing a schematic configuration of a developing device 100 according to the present embodiment, which is mounted on the image forming apparatus as described above. For example, an image forming apparatus including the developing device 100 corresponding to each color of magenta, yellow, cyan, and black forms a color image using each color of magenta, yellow, cyan, and black by development by the developing device 100. In addition to the developing device 100 including the developing roller 110 that forms a toner image, the image forming apparatus includes a recording medium conveying unit that conveys a sheet, a transfer unit that secondarily transfers the toner image to the sheet, and an image on the peripheral surface. Is provided with a photosensitive drum 30 that is an electrostatic latent image carrier on which a toner image is formed, and a fixing unit that adheres a toner image to a sheet.

  When an image signal of a recorded image is input to such an image forming apparatus, the control unit of the image forming apparatus uniformly charges the surface of the photosensitive drum 30 to a predetermined potential by a charging roller based on the received image signal. To charge. Thereafter, the exposure unit irradiates the surface of the photosensitive drum 30 with laser light to form an electrostatic latent image. On the other hand, in each developing device 100, the toner T (developer) in the developing chamber is carried on the developing roller 110 by the toner supply roller 120 (developer supply body).

  Then, when the toner is conveyed to a region facing the photosensitive drum 30 by the rotation of the developing roller 110, the toner carried on the developing roller 110 becomes an electrostatic latent image formed on the peripheral surface of the photosensitive drum 30. The electrostatic latent image is developed. Such development is performed for each color of magenta, yellow, cyan, and black. The toner image thus formed is primarily transferred from the photosensitive drum 30 to the transfer belt in a region where the photosensitive drum 30 and the transfer belt face each other. Then, the toner image is secondarily transferred onto the sheet conveyed by the recording medium conveyance unit. Thereafter, the sheet onto which the toner image has been secondarily transferred is conveyed to the fixing unit and fixed, and is discharged outside the image forming apparatus.

  Here, the developing device 100 includes, in addition to the developing roller 110 described above, a toner supply roller 120, a toner containing chamber 130 (developer containing chamber), a developer regulating member having an elastic blade 142, a developing chamber 150, a toner reservoir. 160 (developer storage part), the partition wall 170, the conveyance member 135, and the stirring member 165 are provided. In the image forming apparatus, the developing device 100 is provided corresponding to each color of magenta, yellow, cyan, and black, but the basic configuration is the same except that the type of toner as a developer is different. Therefore, the individual description is omitted below.

  The toner storage chamber 130 is a chamber for storing the toner T. The developing chamber 150 is a chamber in which development is performed by the developing roller 110, and is disposed adjacent to and above the toner storage chamber 130. A partition wall 170 is provided between the toner storage chamber 130 and the development chamber 150, and the partition wall 170 partitions the toner storage chamber 130 and the development chamber 150. An opening 172 is provided in a part of the partition wall 170, and the toner storage chamber 130 and the developing chamber 150 are connected via the opening 172. The toner storage chamber 130, the developing chamber 150, and the partition wall 170 are integrally formed.

  The toner storage chamber 130 is provided with a conveying member 135 that conveys the toner T to the developing chamber 150. The conveyance member 135 is a conveyance member having a rotatable elasticity, and develops a predetermined amount of toner T accommodated in the toner accommodation chamber 130 through the opening 172 of the partition wall 170 by rotating. It is transferred into the chamber 150.

  In the toner supply roller 120, the toner T supplied from the toner storage chamber 130 by the conveying member 135 and the toner T scraped off from the developing roller 110 by the developer regulating member 140 (see FIG. 9) to be described later are stirred. And a supply member for supplying the toner T, which has been stirred and mixed, to the developing roller 110. The toner supply roller 120 is disposed in the developing chamber 150 so as to face the developing roller 110 so as to abut on the circumferential surface of the developing roller 110. The toner supply roller 120 is made of an elastic member such as polyurethane foam, and is formed so as to be elastically deformable. The toner supply roller 120 is in contact with the developing roller 110 in an elastically deformed state.

  The toner supply roller 120 rotates, for example, counterclockwise, and is configured to move in the opposite direction to the developing roller 110 in a contact area with the developing roller 110 that also rotates counterclockwise. Toner supply roller 120 having such a configuration has agitated and mixed toner T attached to the surface thereof, and the surface of toner supply roller 120 abuts on the surface of development roller 110, so that development is performed from toner supply roller 120. The toner T is supplied to the roller 110, and the developing roller 110 carries the toner. In addition, the toner supply roller 120 peels off the toner T that has not been used for development through the development nip with the photosensitive drum 30 simultaneously with the supply of the toner T, and the toner T is developed for a long time. It also has a function of preventing the charge amount from excessively rising due to staying on the roller 110.

  The developing roller 110 carries the toner T supplied from the toner supply roller 120 on its surface, conveys the toner T to a region facing the photosensitive drum 30, and is formed on the peripheral surface of the photosensitive drum 30. This is a member for moving the toner T to the electrostatic latent image and developing the electrostatic latent image. The member is opposed to the toner supply roller 120 so as to abut on the peripheral surface of the toner supply roller 120 and is also photosensitive drum 30. Is disposed in the developing chamber 150 so as to face the surface.

[Development roller configuration]
According to the present invention, on the outer peripheral surface of the developing roller as the developer carrying member, the regularly arranged identification formed by intersecting the first inclined groove and the second inclined groove having different groove depths and groove widths. By providing the developer carrying surface exhibiting the above surface shape, it is possible to comprehensively cope with the above new problems in addition to the problems pointed out conventionally.

  The developing roller of the present invention comprises a first inclined groove that is spirally continuous on the outer peripheral surface of the developer carrying member and is formed at a constant inclination angle with respect to the circumferential direction (rotation direction) and the direction of the rotation axis. A developer formed by intersecting a second inclined groove which is continuous in a spiral shape formed at a constant inclination angle with respect to the circumferential direction and the direction of the rotation axis and has a deep groove depth and a wide groove width. It is characterized by having a supporting surface, for example, after surface processing a roller base material such as an aluminum alloy or an iron alloy by a known method such as a rolling method or an etching method, polishing or plating, if necessary Manufactured by adding additional machining.

  FIG. 2 shows an embodiment of the present invention. The developing roller 110 is arranged on the outer peripheral surface of the developing roller 110 in the direction of arrow A with an inclination angle α with respect to the direction (X) of the rotation axis of the developing roller 110. Formed by intersecting the formed spiral-shaped first inclined groove 201 and the spiral-shaped second inclined groove 202 formed in the direction of arrow B with the inclination angle β. It has a developer carrying surface.

  The convex portion 203 on the surface of the developer carrying member of the developing roller 110 has a rectangular shape or a parallelogram shape, and has a trapezoidal shape when viewed in section along the line CC in the drawing. In the developing roller 110, the first inclined groove 201 having a groove depth deeper and narrower than the second inclined groove 202 regularly crosses the second inclined groove 202 at regular intervals. The inclined groove 202 remains as a terrace-shaped stepped portion 202 between the convex portion 203 and the convex portion 203. As a result, the developer carrying surface has a stepped structure from the top surface of the convex portion 203 to the concave portion 201 (first inclined groove) via the step portion 202.

  By the way, when the developer is supplied onto the developing roller 110 having the developer carrying surface having the above surface shape, first, the toner particles on the top surface of the convex portion 203 are separated from the developer regulating member 140 (FIG. 9), the roller falls down toward the stepped portion 202 and the recessed portion 201 while rolling on the slope of the protruding portion 203. At this time, the first developer exists in the stepped portion 202 and the concave portion 201, but the toner particles moved from the convex portion 203 fill the space of the stepped portion 202 and the concave portion 201 while pushing out the first developer. .

  Further, among the toner particles that have reached the stepped portion 202, the toner particles that are not sufficiently charged are not sufficiently charged with the electrostatic force on the surface of the developer carrying member, and thus are further pushed out to the slope of the stepped portion 202 and transferred. While moving, it descends toward the concave portion 201, which is the deepest portion, and fills the space of the concave portion 201 while joining with toner particles and the like that have fallen from the top surface of the convex portion 203.

  As described above, the toner particles on the developing roller of the present invention can be quickly charged in a short period of time passing through the contact portion between the developing roller and the developer regulating member. In addition, the toner particles that have been charged quickly are pushed into the first inclined groove and the second inclined groove on the developer carrying surface while being pressed by the developer regulating member. Since repulsive force is generated due to uniform charging, unnecessary packing of toner particles is prevented in advance.

  The first inclined groove and the second inclined groove forming the developer carrying surface of the developing roller 110 have different groove depths and groove widths, and the first inclined groove is inclined with respect to the second inclined groove. It is set so that the groove is deep and the groove width is narrow. Accordingly, the shape of the stepped portion formed by the intersection of the first inclined groove and the second inclined groove is a preferable function as a developer carrying member for a developing roller having a developer carrying surface formed only by the inclined groove. Can be granted. That is, by setting the first inclined groove so that the inclined groove is deeper and the groove width is narrower than the second inclined groove, a step surface having a preferred width and height can be provided in the step portion. It becomes possible. For this reason, the above-described effects are easily exhibited.

  By the way, FIG. 3 shows a state of a gap generated when a developer regulating member such as an elastic blade is brought into contact with a conventional developing roller (Patent Document 2) in which inclined grooves are intersected to provide a grid-like uneven surface. It is explanatory drawing which showed typically. When the developer carrying surface 300 moves in the direction of the arrow (from the lower side to the upper side in the figure) as the developing roller rotates, the contact position with the developer regulating member 140 is also changed from the contact position 3a in the figure. It moves toward the contact position 3c. At this time, at each contact position, a gap is formed between the developer regulating member 140 and the developer carrying surface 300 so that the inside and outside of the developing device communicate with each other. It can be seen that the shape and size change (see the cross-sectional view in the figure). In particular, at the abutting position 3b, the gap as described above becomes large, and the ability to block air blowing from the inside of the developing device caused by the rotation of the developing roller is remarkably reduced, so the amount of air blowing and the flow velocity at that moment increase. This creates a situation where toner particles are easily blown away.

  On the other hand, in the developing roller according to the present invention, the first inclined groove and the second inclined groove having different groove depths and groove widths are crossed on the outer peripheral surface of the developing roller. Can be controlled moderately.

  FIG. 4 is an explanatory view schematically showing the state of the gap generated when the developer regulating member comes into contact with the developing roller of the present invention. When the contact position with the developer regulating member 140 is moved from the contact position 4a in the drawing toward the contact position 4c as the developing roller rotates, the contact position 4a and the contact position 4c Since a gap is formed between the first inclined groove having a deep groove depth and a narrow groove width, it is possible to reduce such a gap that the inside of the developing device communicates with the outside. Further, at the contact position 4b, the gap can be minimized by the stepped portion 202 formed by the second inclined groove having a shallow groove depth and a wide groove width. As the blowing is prevented and the blown off toner particles are greatly reduced, it is possible to stably include appropriate air in the developer by alternately arranging the gaps having different sizes. While suppressing the packing of toner particles and the like, it is possible to further impart powder characteristics that are favorable for development.

  Further, as a result of intensive studies, the present inventors have found that the above-described effects are obtained above the step formed by the first inclined groove and the step formed by the second inclined groove on the developer carrying surface. It was found that it is greatly related to the relative ratio of space volume. That is, in FIG. 5A, the ZB portion of the stepped portion 202a existing between the adjacent convex portions 203a and 203c with respect to the spatial volume A of the ZA portion existing between the adjacent convex portions 203a and 203b. By controlling the surface shape so that the ratio (B / A) of the space volume B of the toner is 0.9 or more and 4.0 or less, the toner particles on the developer carrying member always have a good charge amount and carrying amount. Therefore, it is possible to reduce the influence on a large number of prints and fluctuations in the use environment, and always repeat good image formation.

  Furthermore, matching with the image forming apparatus is also good, and in particular, it is possible to preferably control the contact state with the developer regulating member on the outer peripheral surface of the developer carrying member. It is possible to make the air blowing from the inside of the developing device to be in a preferable state.

  These solutions solve the above-mentioned problems that have been pointed out or have existed in the past, realize excellent development characteristics, prevent toner scattering and toner smearing in non-image areas, and increase mass productivity. An excellent developing roller, developing device, process cartridge, and image forming apparatus can be provided.

  Note that when the value of B / A is less than 0.9, the relative amount of toner particles present on the stepped portion 202 is small, so that it is difficult to obtain the above effects. On the other hand, when the value of B / A exceeds 4.0, the amount of toner particles on the stepped portion 202 becomes excessive, and movement to the concave portion 201 becomes difficult. For this reason, the charged state becomes unstable, and it becomes difficult to carry and hold the toner particles on the stepped portion 202, and the toner particles in the concave portion 201 are easily packed, which causes image fogging and filming. Become. Further, in this case, since the volume of the convex portion 203 is reduced, a toner particle blowing phenomenon is likely to occur.

  By the way, when the first inclined groove is deeper and wider than the second inclined groove, or when the groove depth and the groove width are the same, the shape of the stepped portion becomes insufficient, Not only does the above effect not appear, but particularly when the first inclined groove is deeper and wider than the second inclined groove, and the B / A value is 1.0 or less. Therefore, the above problems tend to occur frequently.

  In the present invention, the spatial volume A and the spatial volume B are defined as follows. That is, as shown in FIG. 5B, the ZA portion is a part of the recess 201a, and the space volume A is the product of the depth d1 ′ and the width of the recess 201a (the cross-sectional area of the recess 201a). The width W2 of the convex portion 203a on the concave portion 201a side. Further, the ZB portion is a portion of a portion where a part of the second inclined groove that has been crossed and torn by the first inclined groove remains as the stepped portion 202a, and the space volume B is the depth of the stepped portion. It can be determined by multiplying the product of d1 ′ and the width (corresponding to the cross-sectional area of the stepped portion 202a) by the width W1 of the convex portion 203a on the stepped portion 202a side.

  For example, when the developer carrying member is a developing roller, first, eight different projecting portions are selected from a total of three locations near the central portion and the left and right end portions of the developing roller, and the projecting portions are adjacent to the projecting portions. The maximum height difference with respect to is measured (see (b) of FIG. 6), and the average value thereof is defined as the depth d1 of the recess. Similarly, the average value of the maximum height differences with respect to the step portion adjacent to the convex portion is obtained and set as the depth d2 of the step portion (not shown).

  Next, a lower point corresponding to 10% of the depth d1 of the concave portion (hereinafter referred to as “10% lower point”) is determined from the highest point of any convex portion (see (b) in FIG. 6). After obtaining a projection image of the top surface of the convex portion formed when the surface of the convex portion extending between the contour lines connecting the 10% lower point from the highest point of the convex portion is projected onto the plane from the vertically upper side, the projected image touches the projected image. A parallelogram or rectangular portion surrounded by a straight line parallel to the forming direction of the first inclined groove and a straight line parallel to the forming direction of the second inclined groove is defined as a convex top surface (see FIG. 6). (See (c)), the average value of the width of the convex portion 203 on the stepped portion side is defined as the width W1 of the convex portion 203, and the average value of the width of the convex portion 203 on the concave portion side is defined as the width W2 of the convex portion 203.

  Further, as shown in FIG. 7 (a), the width of the concave portion 201 is a depth point half the maximum height difference d1 with respect to the convex portion 203 relative to the concave portion 201 on the side surface of the convex portion 203 inside each inclined groove. It is determined by the average value of the interval between the parallel lines extrapolated to. Further, the width of the stepped portion 202 is similarly determined using the maximum height difference d2 from the convex portion 203, and the space volume A and the space volume B can be obtained based on these results.

  For the shape measurement of the developer carrying surface on the developer carrying body as described above, a conventionally known method can be used. For example, a non-contact type surface shape measuring device, a shape measuring laser microscope, etc. The obtained surface shape information can be geometrically determined on the drawing by analyzing with the analysis tool attached to the apparatus as described above or using CAD (Computer Aided Design) or the like. .

  In the present invention, it is a preferred embodiment of the present invention to make the average groove interval of the first inclined grooves equal to the average groove interval of the second inclined grooves, and the toner application state on the surface of the developer carrying member is made uniform. In addition, the contact state with the toner regulating blade and the toner supply roller is preferable, and the self-cleaning performance and the wear state between the components can be appropriately maintained.

  Further, when the developing roller of the present invention is manufactured by a rolling method, not only the first inclined groove and the second inclined groove can be simultaneously rolled, but also the shape of the groove and the convex portion after being rolled. Since the finish of the toner becomes uniform and the charged state and the regulated state of the toner can be made more favorable, it is possible to contribute to the improvement of mass productivity and finish quality of the developing roller.

  Note that the average groove interval of the first inclined grooves and the average groove interval of the second inclined grooves according to the present invention are the average values of the intervals between the top surfaces of the convex portions obtained as described above ((b) in FIG. 7). reference).

  By the way, even when the developing roller of the present invention uses a non-magnetic one-component developer that cannot use magnetic restraint force, the developer carrying surface has an appropriate surface shape as described above. Therefore, good image formation is possible.

  In particular, by setting the groove depth of the first inclined groove to 105% or more and 190% or less of the weight average particle diameter (D4) of the non-magnetic one-component developer to be used, toner stains and the like in the non-image forming area can be prevented. In particular, even when a non-magnetic one-component developer composed of a binder resin, a colorant, a release material and an inorganic fine powder is used without containing a charge control material in the developer. The toner particles can be appropriately charged.

  Here, the weight average particle diameter of the nonmagnetic one-component developer will be described. In the present invention, the weight average particle size (D4) of the one-component developer and the number of toner particles of 3 μm or less in the number-based particle size frequency distribution are, for example, a precision particle size distribution measuring device “Multisizer 3” (Beckman “Toner particle size distribution measurement method (http://www.beckmancounter.co.jp/”) described on the Internet website of Beckman Coulter, Inc. product / product03 / toner / 04.html) "and the like.

  As a specific measurement method, 100 ml of an electrolytic solution “Isoton II-pc” (manufactured by Beckman Coulter) is prepared in a beaker for producing a suspension, and a surfactant (preferably LAS; After adding 0.1 g of a chain alkylbenzene sulfonate), 5 mg of a measurement sample (toner particles or toner) is added to obtain a toner suspension. Next, in order to enhance the dispersibility of the measurement sample in the toner suspension, an ultrasonic irradiation process from the outside is performed for 2 minutes using an ultrasonic bath or the like to prepare a measurement sample. An aperture tube having an opening diameter of 50 μm is used, and the volume and number of the measurement sample are measured for each channel to calculate the volume distribution and number distribution of the measurement sample. From the calculated distribution, the weight average particle diameter (D4) of the measurement sample and the number of toner particles of 3 μm or less in the number-based particle diameter frequency distribution are obtained.

  The developer according to the present invention may be a one-component developer composed only of toner (hereinafter also referred to as “toner particles”) or a two-component developer obtained by mixing a toner and a magnetic carrier. In particular, the developing roller of the present invention is very effective for a non-magnetic one-component developer that is disadvantageous in terms of charge imparting property and transportability on the developing roller.

  The developer according to the present invention may be produced using a so-called pulverization method, or may be produced using an emulsion aggregation method or a phase inversion emulsification coalescence method. From this point of view, it is preferable to use the emulsion aggregation method or the phase inversion emulsification coalescence method.

  In the emulsion aggregation method, polymerization is carried out by dispersing a polymerizable monomer, a polymerization initiator, an emulsifier (surfactant), etc. in water, and the dispersion containing the resin particles obtained as a result of the polymerization is treated with a colorant and a release agent. It is mixed with a dispersion containing a coagulant (electrolyte) and the like, such as a mold agent and a charge control agent. Next, the obtained mixed dispersion is agglomerated and heat-fused to produce desired colored particles.

  Further, the dispersion containing the second resin particles is further mixed with the colored particles thus obtained, and the second resin particles are adhered to the colored particles and heat-fused to form the second resin. A coated film may be formed. Thereby, colored particles having a core-shell structure in which the colored particles are used as a core and the second resin is used as a shell can be obtained. The colored particles having a core-shell structure can prevent the release agent component from being exposed to the surface of the colored particles, and can further prevent the wax (release agent) component from adhering to a device such as a developing roller.

  Examples of the polymerizable monomer in the emulsion aggregation toner include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-ethylstyrene, vinyltoluene, 2 , 4-dimethylstyrene, pn-butylstyrene, p-phenylstyrene, p-chlorostyrene, divinylbenzene, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid n-octyl, dodecyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate Isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, ethylene Glycol, propylene glycol, maleic anhydride, phthalic anhydride, ethylene, propylene, butylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propylene acid, acrylonitrile, methacrylonitrile, vinyl methyl ether , Vinyl ethyl ether, vinyl ketone, vinyl hexyl ketone, vinyl naphthalene and the like.

  In the emulsion aggregation method, these polymerizable monomers are polymerized to produce resin particles. The resin particles produced as a result of the polymerization are homopolymers of the above-mentioned polymerizable monomers. It may be a copolymer. Moreover, it is preferable that the resin particle produced | generated as a result of superposition | polymerization is a styrene acryl-type copolymer from a charging viewpoint.

  Colorants include carbon black, lamp black, magnetite, titanium black, chrome yellow, ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, calco oil blue, quinacridone, benzidine yellow, rose bengal Malachite Green Lake, Quinoline Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 180, C.I. I. Solvent Yellow 162, C.I. I. Pigment blue 5: 1, C.I. I. Dye and pigment such as CI Pigment Blue 15: 3 can be used alone or in combination.

  In addition, paraffin wax, micro wax, micro crystallin wax, cardelilla wax, carnauba wax, rice wax, montan wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, etc. are used as mold release agents. Is possible. Among these release agents, polyethylene wax, polypropylene wax, carnauba wax, ester wax, etc. are preferably used, and the maximum endothermic peak temperature measured by differential scanning calorimetry (DSC) is 50 to 120 ° C. However, it is particularly preferably used from the viewpoint of preventing toner sticking to the surface of the developing roller.

  Examples of the polymerization initiator in the emulsion aggregation method include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4′-azobiscyanovaleric acid, t-butyl hydroperoxide, benzoyl peroxide, 2,2 '-Azobis-isobutyronitrile and the like. In this embodiment, these polymerization initiators can be appropriately selected and used.

  Examples of the emulsifier (surfactant) include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate, dodecyl ammonium chloride, Examples include dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, hexadecyl trimethyl ammonium bromide, dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, and the like. In this embodiment, these emulsifiers can be appropriately selected and used.

  Examples of the flocculant (electrolyte) include sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, sodium sulfate, potassium sulfate, lithium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, aluminum sulfate, and iron sulfate. Etc. In the present embodiment, these flocculants can be appropriately selected and used.

  Although it is the component ratio of these additives, it is preferable that a mold release agent is 3-10 mass parts with respect to 100 mass parts of polymerizable monomers, More preferably, it is 4-8 mass parts. Moreover, it is preferable that a coloring agent is 3-15 mass parts with respect to 100 mass parts of polymerizable monomers, More preferably, it is 5-10 mass parts.

  Further, the addition amount of the polymerization initiator in the emulsion polymerization is preferably 0.03 to 2 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the polymerizable monomer. is there. It is preferable that the addition amount of an emulsifier (surfactant) is 0.01-0.1 mass part with respect to 100 mass parts of polymerizable monomers. The addition amount of the flocculant (electrolyte) is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Further, as the colored particles as described above, those obtained by a phase inversion emulsification coalescence method may be used. The phase inversion emulsification coalescence method is, for example, a method described in Japanese Patent No. 3,867,893. (1) By emulsifying a mixture containing at least a polyester resin and an organic solvent in an aqueous medium, A first step of forming fine particles of the mixture in the medium; (2) a second step of adding a dispersion stabilizer and sequentially adding electrolytes to coalesce the fine particles to produce an aggregate of fine particles; (3 This is a method of producing resin particles by sequentially removing the organic solvent contained in the agglomerate, separating and washing the fine particles from the aqueous medium, and then drying them.

  Further, when a styrene acrylic resin is used as the binder resin, since the resin has excellent moisture resistance, it is possible to produce a binder resin having excellent charging stability. When a polyester resin is used as the binder resin, it is possible to produce a binder resin that is excellent in transparency of the obtained image and suitable for a color image.

  The colored particles obtained by the emulsion aggregation method and the colored particles obtained by the phase inversion emulsification and coalescence method generally do not contain a charge control agent and are therefore difficult to use as a one-component developer. Therefore, it is possible to impart good charge.

  By the way, by adding an external additive such as an inorganic fine powder to the developer of the present invention, not only is a suitable powder characteristic imparted to the toner particles, but also the matching with the developing roller of the present invention is good. It will be a thing.

  The inorganic fine powder used in the developer according to the present invention is not particularly limited, and conventionally known inorganic fine powder can be used. For example, silica fine powder, titania fine powder, and surfaces thereof. Treated fine powder and the like. Among them, the inorganic fine powder whose surface is treated with silicone oil forms a silicone oil film on the surface of the developing roller of the present invention, so that it can increase the charging speed of the developing roller or contribute to the self-cleaning effect. I can do it. In particular, by using a silicone oil-treated inorganic fine powder having a number average particle diameter of 35 to 65 nm in an amount of 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the colored particles, the ability of the developing roller of the present invention can be improved. It can be fully demonstrated. Furthermore, the presence of the hydrophobic treated inorganic fine powder having a number average particle size of 70 to 200 nm is particularly preferable because the above-described effects can be sustained.

  Examples of the silicone oil used in the silicone oil-treated inorganic fine powder according to the present invention include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, vinyl group-containing silicone oil, alkyl-modified silicone oil, and α-methylstyrene. Examples include modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

  Here, the number average particle diameter of the inorganic fine powder according to the present invention is, for example, after taking an enlarged photograph of the inorganic fine powder to be measured, and then the outline of the image of the measurement object in the enlarged photograph becomes clear Thus, the image contrast is adjusted to obtain an image for measurement of the number average particle diameter. Then, after appropriately enlarging the measurement image, 50 or more inorganic fine powders are randomly selected, the major axis of the primary particles is measured using a caliper or a ruler, and the number average particle size is calculated. I can do it.

  The developer according to the present invention may contain a charge control agent or a release agent. For example, as the charge control agent, a metal compound of an aromatic carboxylic acid such as salicylic acid, an azo dye or an azo pigment metal Examples thereof include a salt or metal complex, a polymer compound having a sulfonic acid or carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, and calixarene.

  Next, an example of a manufacturing method suitable for the developing roller of the present invention will be described.

  FIG. 8 is a diagram showing an outline of a method for manufacturing the developing roller 110 according to the present invention. The developing roller 110 of this embodiment can be manufactured by forming two types of inclined grooves that intersect each other on a roller material 803 having a cylindrical shape made of a metal or alloy such as copper, aluminum, and stainless steel. More specifically, the first inclined grooves 201 that are spirally continuous by a rolling method in which a pair of dies 801 and 802 that rotate in the same direction are pressed against the surface of the roller material 803 in a predetermined direction. And the second inclined groove 202 is formed.

  The rotational axes of the dies 801 and 802 are not parallel to the central axis of the roller material 803 but are inclined by the same angle in the opposite direction (for example, -1 ° with respect to 1 °), thereby causing the roller material 803 to rotate. The thrust force resulting from the rotation of the dies 801 and 802 is applied, and the roller material 803 moves along the direction of the axis of rotation of the roller material 803 (right direction in the figure) as the dies 801 and 802 rotate. Sent.

  Each of the dies 801 and 802 has a shape having a spiral protrusion on the outer peripheral surface of the cylinder. The pitch of the spiral protrusions in the die 801 is P1, and the spiral angle is θ1. When the protrusions are pressed against the roller material 803, the surface of the roller material 803 is plastically deformed, and the first inclined groove 201 continuous in a spiral shape having a spiral angle θ1 ′ is formed at the groove interval G1 (see FIG. 7). Engraved. At this time, the spiral angle θ <b> 1 ′ of the first inclined groove 201 can be adjusted by the spiral angle θ <b> 1 of the protrusion of the die 801 and the magnitude of the inclination of the rotation axis of the die 801 with respect to the central axis of the roller material 803. Further, the inclination angle α of the first inclined groove 201 corresponds to an angle obtained by subtracting the value of the spiral angle θ1 'from 90 °. The first inclined groove 201 may be either single or multiple, and can be selected depending on the shape of the die.

  Further, the pitch of the spiral protrusion provided on the die 802 is P2, and the spiral angle is θ2. By pressing the protrusion against the roller material 803, the second inclined groove 202 that is continuous in a spiral shape having a helical angle θ2 'is formed at the groove interval G2 (see FIG. 7). At this time, the spiral angle θ <b> 2 ′ of the second inclined groove 202 can be adjusted by the spiral angle θ <b> 2 of the protrusion of the die 802 and the magnitude of the inclination of the rotational axis of the die 802 with respect to the central axis of the roller material 803. Further, the inclination angle β of the second inclined groove 202 corresponds to an angle obtained by adding the value of the spiral angle θ1 ′ to 90 °. The second inclined groove 202 may be either one or multiple.

The developing roller as described above is preferably used in a one-component developing apparatus using a one-component developer, and among them, a non-magnetic one-component developer that is disadvantageous in terms of charge imparting property and transportability on the developing roller is used. In such a case, a developer regulating member such as an elastic blade is brought into contact with the outer peripheral surface of the developing roller while appropriately pressing (see FIG. 1), so that the toner particles existing on the developer carrying surface of the developing roller can be removed. The charged state and the existing amount can be made suitable for development.
FIG. 9 shows an example of a preferred embodiment of a developer regulating member that is used when a one-component developer is applied to the developing roller. The developer regulating member 140 includes a base 143, an elastic blade 142 (elastic contact body), and The elastic blade 142 includes a fixing member 141 that supports and fixes the elastic blade 142 to the base body 143. The elastic blade 142 has an end portion extending in parallel with the direction of the rotation axis of the developing roller. The horizontal width of the elastic blade 142 in the direction of the rotation axis is arranged so that the groove depth of the inclined groove existing on the developer carrying surface provided on the surface of the developing roller is larger than the weight average particle diameter of the toner T. It is preferable. When the distance from the bottom surface is equal to or less than the weight average diameter of the toner T, not only a sufficient amount of toner can be secured on the developing roller, but also image defects on vertical stripes are likely to occur.

  As shown in FIG. 9, a developer regulating member having an elastic blade 142 is brought into pressure contact with the surface of the developer carrying member, and the “protruding amount” of the developer regulating member is changed to be on the surface of the developer carrying member. A thin layer of a desired amount of developer (toner) can be formed.

  In the present invention, the “protruding amount” of the developer regulating member refers to the development existing on the extension line passing through the tip of the developer regulating member from the rotation center of the developer carrying member and reaching the outer periphery of the developer carrying member. This is the distance J from the intersection point of the tip of the agent regulating member with the pressure contact surface side to the intersection point with the outer peripheral surface of the developer carrier, and can be determined geometrically on the drawing by CAD or the like.

  As a simple measuring method, there is a method of actually measuring the length from the contact mark between the developer regulating member and the developer carrying member to the tip of the developer carrying member, and the like can be used instead.

  Further, the elastic blade 142 regulates the layer thickness of the toner carried on the top surface of the convex portion of the developing roller so that the toner particles become one layer or less. That is, the elastic blade 142 prevents excessive toner particles from being carried on the top surface of the convex portion of the developing roller 110. As a result, the toner particles carried on the developer carrying surface of the developing roller 110 can roll uniformly and efficiently, so that it is possible to quickly shift to a charged state suitable for development. On the contrary, if excessive toner particles are present on the top surface of the convex portion, not only the excessive toner particles themselves cannot be given good charging, but also the rolling of other toner particles is inhibited. The charged state becomes worse.

  Further, since the developing roller according to the present invention can adjust the depth and width of the inclined groove constituting the developer carrying surface as appropriate, the dimensional tolerance of the protruding amount of the elastic blade 142 with respect to the developing roller can be set wide. Even if the contact portion of the elastic blade 142 is worn out due to many times of image formation, and the protrusion amount changes, the protrusion amount after the abrasion may still remain within a predetermined dimensional tolerance. It becomes easy. Furthermore, self-cleaning can be performed by setting the contact portion of the elastic blade 142 to be worn. For example, the elastic blade 142 has a surface hardness ratio of 0.20 to 1. A metal plate-like member formed of phosphor bronze or stainless steel of less than 00 is preferably selected.

  Thus, filming of the toner can be prevented, so that not only the charged state of the toner particles but also the supported state of the toner particles can be maintained in the best state. As a result, it is possible to suppress the occurrence of vertical stripe-shaped image density unevenness, and to minimize deterioration / fluctuation of image density, non-image area corresponding to the printed background, toner contamination, fine line reproducibility, and color tone. An excellent developing device can be provided.

  In the present invention, the surface hardness of the contact portion of the developer regulating member with respect to the developer carrying member can be measured with reference to “JIS Z 2244; 2009 (Vickers hardness test-test method)” or the like. At this time, when measuring the surface hardness of the developer-carrying surface of the developer-carrying member, if the test surface required for measurement cannot be secured due to the influence of the surface shape, the unprocessed parts on the left and right ends of the developer-carrying surface The test surface shall be used for measurement.

  In addition, when the developing device as described above is used in a process cartridge type image forming apparatus that is easily influenced by external deformation stress, the above-described effects are very greatly manifested.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

<Example of production of developer carrier>
[Development Roller Production Example 1]
Two inclined grooves (FIG. 2) intersecting the cylindrical surface after the outer peripheral surface (hereinafter referred to as “cylindrical surface”) of a cylindrical roller base material made of a carbon steel pipe having a diameter of 18 mm is polished by a centerless polishing machine. In order to form a reference), a roller base material was installed in a rolling device provided with first and second dies in which ridges corresponding to the respective grooves were formed. Then, while rotating each die and the roller base material at a constant speed, the die was pressed while feeding out the roller base material, and the first inclined groove and the second inclined groove were rolled into the roller base material.

  As a result, the cylindrical surface has a plurality of regularly arranged convex portions, stepped portions and concave portions surrounding the convex portions on the surface thereof, and the surfaces of the convex portions are part of the same cylindrical surface. A rolled roller was obtained. The obtained rolling roller is immersed in a heated degreasing solution and degreased, and then immersed in a Ni-P plating bath, subjected to electroless plating on the cylindrical surface, washed and dried. “Developing roller 1” having a developer carrying surface having the surface structure shown in FIG.

  On the outer peripheral surface of the “developing roller 1” obtained, a developer having a regularly arranged surface shape formed by intersecting a first inclined groove and a second inclined groove having different groove depths and groove widths. The carrying surface could be confirmed. When the surface shape of the obtained “developing roller 1” was measured, the inclination angle α of the first inclined groove was 45 °, the groove depth was 12 μm (vs. toner weight average particle diameter D4 ratio: 185%), and the groove width. Was 66 μm. The inclination angle β of the second inclined groove is 135 °, the groove depth is 9 μm, and the groove width is 100 μm. The first inclined groove is deeper and narrower than the second inclined groove. It was confirmed. Further, the groove interval between the first inclined groove and the second inclined groove is 200 μm, the width W2 of the convex portion on the first inclined groove side is 100 μm, and the width W1 of the convex portion on the second inclined groove side is At 134 μm, the volume ratio (B / A) of the spatial volume B to the spatial volume A was 1.52.

[Production Examples 2 to 6 of developing roller]
Except for changing the first and second dies used in the production of the rolling roller and finely adjusting the rolling conditions as appropriate, the developer carrying surface of the developer carrying surface was changed in the same manner as in “Development roller production example 1”. “Developing rollers 2 to 6” having different surface shapes were produced.

[Production Examples 1 to 5 of Comparative Developing Roller]
Except for changing the first and second dies used in the production of the rolling roller and finely adjusting the rolling conditions as appropriate, the developer carrying surface of the developer carrying surface was changed in the same manner as in “Development roller production example 1”. “Comparative developing rollers 1 to 5” having different surface shapes were produced.

[Production Example 6 for Comparative Developing Roller]
Except for changing the first and second dies used at the time of manufacturing the rolling roller and finely adjusting the rolling conditions as appropriate, the shape of the groove portion is V as in “Developing roller manufacturing example 1”. A “comparative developing roller 6” having a developer carrying surface composed of a first inclined groove that is a mold and a second inclined groove that has a U-shaped groove portion was manufactured.

  Table 1 shows the contents of “Developing Rollers 1-6” and “Comparative Developing Rollers 1-6” obtained in “Developing Roll Manufacturing Examples 1-6” and “Comparative Developing Roller Manufacturing Examples 1-6”. It summarizes and shows.

  The Vickers hardness of the surfaces of the “developing rollers 1 to 6” and “comparative developing rollers 1 to 6” obtained above was in the range of 600 to 800 Hv.

<Example of toner production>
[Preparation of resin fine particle dispersion]
The following components were charged into a reaction vessel equipped with a stirrer and replaced with nitrogen while stirring.
-Ion-exchanged water: 550 parts by mass-Nonionic surfactant: 6 parts by mass-Anionic surfactant: 12 parts by mass Next, a dissolved mixture of the following components was added and emulsified and dispersed in the reactor.
Styrene: 370 parts by mass n-butyl acrylate: 50 parts by mass Acrylic acid: 8 parts by mass Dodecanethiol: 24 parts by mass Carbon tetrabromide: 4 parts by mass After emulsification and dispersion, 4 parts by mass of ammonium persulfate was dissolved. 50 parts by mass of ion-exchanged water was added and the temperature was raised to 70 ° C. The emulsion polymerization was continued for 5 hours as it was to obtain a resin fine particle dispersion.

[Preparation of carbon black dispersion]
The following components were charged into a reaction vessel equipped with a high-speed agitator and dispersed in the reaction vessel to obtain a carbon black dispersion.
-Ion exchange water: 200 parts by mass-Nonionic surfactant: 5 parts by mass-Carbon black (BET specific surface area: 80 m ² / g): 50 parts by mass

[Preparation of release agent dispersion]
The following components were charged into a reaction vessel equipped with a high-speed stirring device, and dispersed in the reaction vessel to obtain a release agent dispersion.
-Ion exchange water: 200 parts by mass-Cationic surfactant: 5 parts by mass-Paraffin wax (melting point: 79 ° C): 80 parts by mass

[Production example of black core particles]
The following components were charged into a reaction vessel equipped with a high-speed stirring device.
-Resin fine particle dispersion: 200 parts by mass-Carbon black dispersion: 20 parts by mass-Release agent dispersion: 40 parts by mass-Polyaluminum chloride: 2 parts by mass-Ion exchange water: 500 parts by mass

  After carrying out the dispersion treatment, the temperature was raised to 45 ° C. while stirring, and this state was maintained for 30 minutes. When a part of the dispersion in the reaction vessel was taken out and observed with an optical microscope, formation of aggregated particles having a particle size of about 5 μm was confirmed. 60 parts by mass of the resin fine particle dispersion was added to the dispersion containing the aggregated particles, the temperature in the reaction vessel was raised to 50 ° C., and the state was maintained for 30 minutes. Then, 1N sodium hydroxide aqueous solution was thrown in in reaction container, and the dispersion liquid was adjusted to pH5. After pH adjustment, the temperature was further raised to 95 ° C., and this state was maintained for 4 hours. After cooling, the dispersion containing the agglomerated particles is subjected to solid-liquid separation using a filter, the resulting solid content is washed several times with ion-exchanged water, and heated and dried with “Flash jet dryer (manufactured by SEISHIN ENTERPRISE)”. Black core particles were obtained.

[Production example of yellow core particles]
Instead of carbon black, C.I. I. Except for using 70 parts by mass of Pigment Yellow 180, a yellow pigment dispersion was obtained in the same manner as in “Preparation of carbon black dispersion”, and then in the same manner as in “Production example of black core particles”. Yellow toner particles were obtained.

[Production example of magenta core particles]
Instead of carbon black, C.I. I. Except for using 70 parts by mass of Pigment Red 122, after obtaining a Magenta pigment dispersion by the same method as in “Preparation of carbon black dispersion”, the same method as in “Production example of black core particles” above. Magenta core particles were obtained.

[Production example of cyan core particles]
Instead of carbon black, C.I. I. Except for using 70 parts by weight of Pigment Blue 15: 3, after obtaining a cyan pigment dispersion by the same method as in the above-mentioned “Preparation of carbon black dispersion”, the same method as in the above “Example of production of black core particles” As a result, cyan core particles were obtained.

  In addition, the charge control agent was not used for the black core particles to the cyan core particles obtained in the above [Examples for producing black core particles] to [Production examples for cyan core particles].

[Production Example 1 of Nonmagnetic Monocomponent Black Toner]
The following components were charged into a dry mixing apparatus, premixed for 1 minute at a peripheral speed of 16 m / sec, and then dry mixed (first time) for 4 minutes at a peripheral speed of 40 m / sec.
-Black core particles obtained in "Black Core Particle Production Example 1": 100 parts by mass-Hydrophobized titania fine particles (number average particle size = 20 nm): 1.0 parts by mass Obtained after the first dry mixing The following components were added to the obtained mixture, and dry mixing (second time) was performed again for 4 minutes.
Hydrophobized silica fine particles (number average particle size = 25 nm): 1.0 part by mass Silicone oil-treated silica fine particles (number average particle size = 50 nm): 0.5 part by mass When all dry mixing is completed, sieving Thus, coarse particles were removed to obtain a non-magnetic one-component black toner-1.

[Production Example 2 of Nonmagnetic Monocomponent Black Toner]
In the same manner as in “Preparation Example 1 of Nonmagnetic One-Component Black Toner”, after the first dry mixing, the following components were added to the obtained mixture and again dry mixed (second time) for 4 minutes.
Hydrophobized silica fine particles (number average particle size = 25 nm): 0.5 parts by mass Hydrophobized silica fine particles (number average particle size = 100 nm): 0.5 parts by mass Silicone oil-treated silica fine particles (number average particles) (Diameter = 50 nm): 0.5 part by mass When all of the dry mixing was completed, coarse particles were removed by sieving to obtain nonmagnetic one-component black toner-2.

[Production example of non-magnetic one-component yellow toner]
Non-magnetic one-component yellow toner in the same manner as in “Black toner production example 2” except that the black core particles are changed to yellow core particles and the addition amount of the hydrophobized titania fine particles is changed to 1.1 parts by mass. Got.

[Production example of non-magnetic one-component magenta toner]
The non-magnetic one-component magenta toner is the same as “Black toner production example 2” except that the black core particles are changed to magenta core particles and the addition amount of the hydrophobized titania fine particles is changed to 1.2 parts by mass. Got.

[Production example of non-magnetic one-component cyan toner]
The non-magnetic one-component cyan toner was changed in the same manner as in “Black toner production example 2” except that the black core particles were changed to cyan core particles and the addition amount of the hydrophobized titania fine particles was changed to 1.2 parts by mass. Obtained.

  Each of the one-component developers of the respective colors obtained in the above production examples has a weight average particle diameter (D4) of 6.5 μm, and the number of developer particles of 3 μm or less in the number-based particle size frequency distribution is 10. It manufactured so that it might become number%.

<Example 1>
As an image forming apparatus, replace each color developing unit of “SAMSUNG MultiXpress CLX-8380ND (manufactured by SAMSUN ELECTRONICS)” as a non-magnetic single component developing unit shown in FIG. 1 for A4 size paper. , And modified / adjusted so that image formation is possible at an image output speed of 30 sheets / minute (A4 size paper is output vertically). For each color developing device of the image forming apparatus, the “developing roller R-1” obtained in “Developing roller production example 1” is used, and the elastic contact member of the developer regulating member is a stainless steel thin plate. (Vickers hardness = 350 Hv, ratio of surface hardness of developer regulating member to surface hardness of developing roller = 0.50) was used. At this time, the surface of the “developing roller R-1” has a Vickers hardness of 700 Hv, the surface of the elastic contact member has a Vickers hardness of 350 Hv, and the surface hardness ratio of the developer regulating member to the surface hardness of the developing roller is 0. 50.

150 g of “Non-magnetic one-component black toner-1” obtained in “Non-magnetic one-component black toner production example 1” is introduced into the black-color developing device of the developing device, and the elasticity of the developer regulating member is reduced. The amount of toner carried on the developer carrying surface of the developing roller was adjusted to be 0.30 mg / cm ² by increasing or decreasing the protruding amount of the contact body. The amount of toner carried on the developing roller was adjusted to satisfy the range of 0.30 to 0.35 mg / cm ² . As the transfer material, “full-color copier paper C2 (70 g / cm ² , A4 size) manufactured by Fuji Xerox Co., Ltd.” was used, and a normal temperature and normal humidity environment (23 ° C./55% Rh), a low temperature and low humidity environment (15 ° C./10% Rh) and high-temperature and high-humidity environment (32 ° C / 80% Rh) in each test environment. Image quality evaluation was performed.

The evaluation items and evaluation criteria of the evaluation test are shown below.
[Image quality evaluation]
[1. Image density]
Print an image with a 5mm square solid patch near the four corners and the center, measure the reflection density of the solid patch with a spectrophotometer "Spectro Eye (Gretag Macbeth)", and average the measured values Values were calculated and evaluated according to the following criteria.
A: 1.30 or more (very good)
B: 1.15 or more and less than 1.30 (good)
C: 1.00 or more and less than 1.15 (acceptable level in the present invention)
D: Less than 1.00 (impossible level in the present invention)

[2. Fine line reproducibility]
A fine line pattern having 50 μm horizontal lines arranged at intervals of 100 μm was printed out, and the fine line reproducibility of the obtained image was evaluated according to the following criteria.
A: The fluctuation amount of the line width of the thin line is less than 10% (very good)
B: The fluctuation amount of the line width of the thin line is 10% or more and less than 15% (good)
C: The change of the fine line is 15% or more and can be confirmed visually (in the present invention, acceptable)
Level)
D: Contact between thin wires and tearing of the thin wires themselves can be easily confirmed visually (in the present invention
It is impossible level)

[3. Non-image area (background) toner stains]
During the white image formation, the developer present on the photosensitive drum was transferred to the adhesive surface of “Mending tape (manufactured by Sumitomo 3M)” during the transition from the development process to the transfer process, and was pasted on paper. Measure the reflection density of the object with a spectrophotometer “Spectro Eye (Gretag Macbeth Co.)”, and obtain the numerical value by subtracting the reflection density (blank) when the mending tape is stuck on the paper from the obtained reflection density. Evaluation was made according to the following criteria. A smaller numerical value indicates that toner contamination in the non-image area is suppressed.
A: Less than 0.03 (very good)
B: 0.03 or more and less than 0.07 (good)
C: 0.07 or more and less than 1.00 (Acceptable level in the present invention)
D: 1.00 or more (this is an impossible level in the present invention)

[4. Vertical stripe image density unevenness]
A halftone image composed of a halftone dot pattern was printed, the number of occurrences of vertical stripe-like image shading unevenness generated on the obtained halftone image was measured, and evaluated according to the following criteria.
A: Not generated (very good).
B: Minor vertical stripe-shaped image density unevenness occurs in one place (good)
C: 2-4 occurrences (acceptable level in the present invention)
D: 5 or more occurrences (impossible level in the present invention)

[Evaluation of matching with image forming apparatus]
[1. Charge distribution]
After completion of the printout test, a part of the toner particles carried on the developer carrying surface of the developing roller is collected, and a good charge distribution is measured using “Espert Analyzer EST-3 (manufactured by Hosokawa Micron)”. , Q / d was evaluated for the amount of a positive component (positively charged component). The smaller the amount, the better the charging.

[2. Developer status]
After completion of the printout test, when forming a white image, the developer present on the photosensitive drum is transferred to the adhesive surface of the “mending tape (manufactured by Sumitomo 3M)” during the transition from the development process to the transfer process, Evaluation was made according to the following criteria.
A: Not generated (very good)
B: Minor scattered toner particles on the surface of the developer regulating member facing the photosensitive drum
Adhesion occurs (good)
C: The scattered toner particles reach the surface of the photosensitive drum, but the shape of vertical stripes is uneven.
Not achieved (acceptable level in the present invention)
D: The scattered toner particles reach the surface of the photosensitive drum and form a plurality of vertical streaky irregularities.
(Unusable level in the present invention)

[3. State of developer carrying surface]
After the completion of all tests, the developer roller was rotated for 4 hours without consuming toner, and the state of the developer carrying surface when the developer carrying surface was forcibly stressed was observed under a microscope. According to the evaluation.
A: Not generated (very good).
B: The toner particle fixing portion is less than 10% by area of the developer carrying surface excluding the convex top surface (good
Is good)
C: The toner particle fixing portion is less than 30% by area of the developer carrying surface excluding the top surface of the convex portion (this
(Acceptable level in the invention)
D: The toner particle fixing portion exceeds 30 area% of the developer carrying surface excluding the top surface of the convex portion.
(Unusable level in the present invention)

When the evaluation test was performed according to the above, the obtained image was excellent in image density and fine line reproducibility from the start to the end of the printout in any test environment, as well as toner stains or vertical stripes in the non-image area. Occurrence of image density unevenness was prevented in advance.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated, and the amount of toner carried on the developer carrying surface was 0.32 mg / cm ^2. As a result of the measurement, it was confirmed that even if the toner particles do not contain a charge control agent, the amount of the positively charged component existing as small as 7% by number is maintained at a favorable negative chargeability.
Further, the regulated state of the developer was also maintained in a very good state, and no vertical stripe unevenness or the like of the toner occurred.
Further, after the completion of all tests, even if the developing roller was rotated for 4 hours, very slight toner particles were fixed on the developer carrying surface.
Details of the evaluation results are summarized in Table 2 below.

<Example 2>
“Example 1” except that “Non-magnetic one-component black toner-2” obtained in “Nonmagnetic one-component black toner-2” was used instead of “Non-magnetic one-component black toner-1”. The evaluation test was carried out in the same manner as above.
When the evaluation test was performed according to the above, the obtained image was excellent in image density and fine line reproducibility from the start to the end of the printout in any test environment, as well as toner stains or vertical stripes in the non-image area. Occurrence of image density unevenness was prevented in advance.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated. The amount of toner carried on the developer carrying surface was 0.31 mg / cm ² , and the charge amount distribution at that time was As a result of measurement, it was confirmed that the presence of the positively charged component was very small at 3% by number, and it was possible to maintain better negative chargeability by adding hydrophobic silica fine particles having a large particle diameter to the toner. .
Further, the developer regulation state is also kept in a very good state, and no vertical stripe unevenness of the toner has occurred. Even after the development roller is rotated for 4 hours after the completion of all the tests, the development is continued. The toner particles did not adhere to the contact surface of the developer carrying surface or the elastic contact body of the developer regulating member, and other abnormalities were not observed, and the initial good state was maintained.
Details of the evaluation results are summarized in Table 2.

<Examples 3 to 7>
Instead of “Developing roller R-1”, “Developing roller R-2 to R-6” obtained in “Developing roller production examples 2 to 6” is used as in “Example 1”. An evaluation test was conducted. Details of the evaluation results are summarized in Table 2.

<Example 8>
An evaluation test was carried out in the same manner as in “Example 1” except that a thin sheet of phosphor bronze having a Vickers hardness of 135 Hv was used for the elastic contact body of the developer regulating member.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated, and the ratio of the surface hardness of the developer regulating member to the surface hardness of the developing roller was 0.27. Although the amount of toner carried above and the amount of positively charged components increased, good images were obtained in each environment, and toner stains in non-image areas and image density unevenness in the form of vertical stripes also occurred. It was acceptable.
After the completion of all tests, when the developing roller was rotated for 4 hours, slight toner adhesion occurred on the developer carrying surface and the contact surface of the elastic contact member of the developer regulating member, but this was an acceptable level. .

<Example 9>
An evaluation test was performed in the same manner as in “Example 1” except that a thin stainless steel plate having a Vickers hardness of 600 Hv was used for the elastic contact body of the developer regulating member.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated. The ratio of the surface hardness of the developer regulating member to the surface hardness of the developing roller was 1.20. The amount of toner carried above and the amount of positively charged components are generally maintained, and a good image can be obtained in each environment, and the occurrence of toner stains in non-image areas and image density unevenness in the form of vertical stripes is slight. there were.
Further, after the completion of all tests, when the developing roller was rotated for 4 hours, slight toner sticking occurred on the developer carrying surface and the contact surface of the elastic contact body of the developer regulating member, but this was an acceptable level. .

<Comparative Example 1>
Evaluation test similar to “Example 1” except that “Comparative development roller r-1” obtained in “Comparative development roller production example 1” is used instead of “Development roller R-1”. Carried out.
As a result, since the first inclined groove and the second inclined groove of the “comparative developing roller r-1” have the same groove depth and groove width, the toner carrying state on the developer carrying surface is sufficient. However, in particular, the reproducibility of fine lines in a high-temperature and high-humidity environment was poor, and vertical stripe-shaped image density unevenness occurred.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated. As a result, the amount of toner carried on the developer carrying surface increased to 0.45 mg / cm ² and the charge amount distribution at that time As a result, the abundance of positively charged components was 11% by number.
In addition, vertical streaky unevenness due to scattered toner occurred on the photosensitive drum.
Further, after the completion of all tests, the developing roller was rotated for 4 hours, and the developer carrying surface was observed. As a result, remarkable toner particle fixation occurred, and there was a problem in the regulated state of the developer.

<Comparative Example 2>
Evaluation test similar to “Example 1” except that “Comparative development roller r-2” obtained in “Comparative development roller production example 2” is used instead of “Development roller R-1”. Carried out.
As a result, since the second inclined groove of the “comparative developing roller r-1” has only a groove depth shallower than the first inclined groove without changing the groove width, the toner particles are packed. As a result, the reproducibility of fine lines deteriorated, and the chargeability of the toner was adversely affected. In particular, the groove depth of the first inclined groove exceeds 190% of the weight average particle diameter of the toner particles, and the ratio of the space volume ratio between the first inclined groove and the second inclined groove is less than 0.9. The toner in the non-image area is noticeably contaminated, and there is a problem in matching with the image forming apparatus.

<Comparative Example 3>
Evaluation test similar to “Example 1” except that “Comparative development roller r-3” obtained in “Comparative development roller production example 3” is used instead of “Development roller R-1”. Carried out.
As a result, the second inclined groove of the “comparative developing roller r-3” has a groove width that is wider than the first inclined groove without changing the groove depth. The charging ability was lowered, and the amount of positively charged components was increased to 36%. In addition, since the ratio of the space volume ratio between the first inclined groove and the second inclined groove exceeds 4.0, the toner particles fall into a packing state, and the reproducibility of toner stains and fine lines in the non-image area, Caused a problem in matching with the image forming apparatus.

<Comparative Example 4>
Evaluation test similar to “Example 1” except that “Comparative developing roller r-4” obtained in “Comparative developing roller production example 4” is used instead of “Developing roller R-1”. Carried out.
As a result, the second inclined groove of the “comparative developing roller r-4” is deeper and wider than the first inclined groove, so that the ability to impart charge to the toner particles is reduced, and the toner There is also a problem with the state of regulation. As a result, toner contamination in the non-image area, vertical stripe-shaped image density unevenness, and matching with the image forming apparatus deteriorated.

<Comparative Example 5>
Evaluation test similar to “Example 1” except that “Comparative development roller r-5” obtained in “Comparative development roller production example 5” is used instead of “Development roller R-1”. Carried out.
As a result, the developer carrying surface of the “comparative developing roller r-5” is the first inclined groove whose groove part is V-shaped and the second inclined groove whose groove part is U-shaped. As a result, the toner carrying ability of the developer carrying surface was lowered, and toner stains and vertical stripe-shaped density unevenness occurred in the non-image area.
After completion of the printout test, the state of the toner carried on the developer carrying surface was evaluated. As a result, the amount of toner carried on the developer carrying surface was reduced to 0.20 mg / cm ^2. When the quantity distribution was measured, the amount of positively charged components was very large at 36% by number.
In addition, vertical streaky unevenness of the toner has occurred, and after rotating the developing roller for 4 hours, when the developer carrying surface and the contact surface of the elastic contact member of the developer regulating member are observed, the toner particles The sticking occurred.

Details of the evaluation results are summarized in Table 2.

<Example 8>
In each color developing device of the image forming apparatus, the developer regulation using “developing roller R-1” obtained in “Developing roller production example 1” and a stainless steel thin plate (Vickers hardness = 350 Hv) as an elastic contact member. 150 g of each color toner obtained in the above [Production Example 2 of Nonmagnetic Monocomponent Black Toner] to [Production Example of Nonmagnetic Monocomponent Cyan Toner] is used. By adjusting the protruding amount of the elastic contact body, the amount of toner carried on the developer carrying surface of the developing roller is adjusted to be 0.30 to 0.32 mg / cm ^2, and in each of the above test environments. While supplying the developer, 50,000 graphic images were printed out in the full color mode.
As a result, it was possible to obtain a high-definition graphic image with very slight variation in color.
Further, the developer regulation state is also kept in a very good state, and no vertical stripe unevenness of the toner has occurred. Even after the development roller is rotated for 4 hours after the completion of all the tests, the development is continued. The toner particles did not adhere to the contact surface of the developer carrying surface or the elastic contact body of the developer regulating member, and other abnormalities were not observed, and the initial good state was maintained.

<Comparative Example 6>
Evaluation test in the same manner as in “Example 8” except that “Comparative development roller r-1” obtained in “Comparative development roller production example 1” is used instead of “Development roller R-1”. Carried out.
As a result, there was a problem with fine line reproducibility and vertical stripe image density unevenness, and the resulting graphic image had very large color variations within and between pages and lacked sharpness. Met.
In addition, vertical streaky unevenness due to scattered toner occurred on the photosensitive drum.
Further, after the completion of all tests, the developing roller was rotated for 4 hours, and the developer carrying surface was observed. As a result, remarkable toner particle fixation occurred, and there was a problem in the regulated state of the developer.

110... Development roller (developer carrier)
201 ... 1st inclined groove (or recessed part)
202 ... 2nd inclined groove (or step part)
ZA portion: approximate position ZB of the spatial volume A defined on the first inclined groove ZB portion: approximate position 140 of the spatial volume B defined on the second inclined groove 140 ... developer regulating members 801, 802 ... dice

Claims (16)

A developing roller carrying a developer on an outer peripheral surface,
On the outer peripheral surface, a first inclined groove continuous in a spiral shape formed in a direction inclined with respect to the circumferential direction of the developing roller and the direction of the rotation axis of the developing roller;
A second inclined groove that is inclined with respect to the circumferential direction and the direction of the rotation axis, is formed so as to intersect with the first inclined groove, and is spirally continuous;
The average groove depth of the first inclined groove is larger than the average groove depth of the second inclined groove,
The developing roller, wherein an average groove width of the first inclined groove is smaller than an average groove width of the second inclined groove. The outer peripheral surface is provided with a convex portion sandwiched between the first inclined groove and sandwiched between the second inclined groove,
Ratio of the spatial volume (B) of the second inclined groove existing between the adjacent convex portions to the spatial volume (A) of the first inclined groove existing between the adjacent convex portions ( The developing roller according to claim 1, wherein B / A) is 0.9 or more and 4.0 or less.   The developing roller according to claim 1, wherein an average groove interval of the first inclined grooves is equal to an average groove interval of the second inclined grooves. The developer is a one-component developer including at least a binder resin, a colorant, a release material, and inorganic fine powder,
The developing roller according to any one of claims 1 to 3, wherein an average groove depth of the first inclined groove is 105% or more and 190% or less of a weight average particle diameter (D4) of the developer.   The developing roller according to claim 4, wherein the inorganic fine powder contains a silicone oil-treated inorganic fine powder having a number average particle size of 35 nm or more and 65 nm or less.   The developing roller according to claim 4 or 5, wherein the inorganic fine powder contains a hydrophobicized inorganic fine powder having a number average particle size of 70 nm or more and 200 nm or less. A developer carrier that is rotatably disposed and carries the developer, and a developer carrier that is disposed so as to abut on the outer peripheral surface of the developer carrier, and that is supplied to the developer carrier. A developing device comprising a developer regulating member for regulating the layer thickness,
On the outer peripheral surface of the developer carrying member, a first slope that is spirally formed and formed in a direction inclined with respect to the circumferential direction of the developer carrying member and the direction of the rotation axis of the developer carrying member. A groove and a second inclined groove that is inclined with respect to the circumferential direction and the direction of the rotation axis and that is continuous in a spiral shape formed so as to intersect the first inclined groove;
The average groove depth of the first inclined groove is larger than the average groove depth of the second inclined groove,
The developing device according to claim 1, wherein an average groove width of the first inclined groove is smaller than an average groove width of the second inclined groove. The outer peripheral surface is provided with a convex portion sandwiched between the first inclined groove and sandwiched between the second inclined groove,
Ratio of the spatial volume (B) of the second inclined groove existing between the adjacent convex portions to the spatial volume (A) of the first inclined groove existing between the adjacent convex portions ( The developing device according to claim 7, wherein B / A) is 0.9 or more and 4.0 or less.   The developing device according to claim 7 or 8, wherein an average groove interval of the first inclined grooves is equal to an average groove interval of the second inclined grooves. The developer is a non-magnetic one-component developer including at least a binder resin, a colorant, a release material, and an inorganic fine powder.
The developing device according to claim 7, wherein an average groove depth of the first inclined groove is 105% or more and 190% or less of a weight average particle diameter (D4) of the developer.   The developing device according to claim 10, wherein the inorganic fine powder contains a silicone oil-treated inorganic fine powder having a number average particle size of at least 35 nm and not more than 65 nm.   The developing device according to claim 10 or 11, wherein the inorganic fine powder contains a hydrophobically treated inorganic fine powder having a number average particle diameter of 70 nm to 200 nm.   The developing device according to claim 7, wherein the developer regulating member includes an elastic contact body having an end portion extending in a width direction parallel to the rotation axis of the developer carrying body.   The developing device according to any one of claims 7 to 13, wherein a surface hardness ratio of a contact portion of the developer regulating member with respect to the developer carrying member is 0.20 or more and less than 1.00. An electrostatic latent image carrier;
The process cartridge provided with the developing device as described in any one of Claims 7-14 integrally formed into a cartridge with the said electrostatic latent image carrier. An image forming apparatus comprising the developing device according to claim 7 or the process cartridge according to claim 15.