JP2008129443A - Cleaning unit, belt unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To show the optimization guidance of the width dimension of each element so as to develop a stable cleaning performance over a long period, regarding a cleaning unit where an application member for applying a solid lubricant is disposed on the downstream side of a cleaning blade, and a leveling blade is disposed on the downstream side of the application member. <P>SOLUTION: When the widthes of the cleaning blade 103, a brush roller 104, the solid lubricant 107 and the leveling blade 105 are set to L1, L2 L3 and L4 respectively, the widths of L1 to L4 are set so as to satisfy L4≤L1<L3<L2, (wherein L4>image formation width). By establishing L3>L1, the entanglement of the blade is prevented, by establishing L3<L2, the lubricant is usefully consumed. Also, by establishing L4≤L1, the entanglement of the leveling blade 105 is prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, and a multifunction machine having at least one of them, a cleaning unit used in the image forming apparatus, and a belt unit.

Conventionally, in an image forming apparatus using an electrophotographic method, in order to prevent transfer failure during primary transfer and secondary transfer of a toner image, or to improve the cleaning performance of transfer residual toner on an image carrier. A technique is known in which a lubricant is applied to the surface of an image bearing member (including an intermediate transfer member) to lower the coefficient of surface friction and reduce the adhesion to toner.
Among them, for example, as shown in FIG. 4b of Patent Document 1, a configuration is provided in which a lubricant is applied after the cleaning process, and a smoothing blade is provided further downstream to further smooth the lubricant using a blade member. It is known that the structure is effective in stabilizing the surface friction coefficient, and this improves the cleaning performance.

However, it is necessary for the cleaning device not only to be cleanable but also to reliably prevent the cleaning blade from turning up. “Blade turning” refers to a phenomenon in which the blade edge is drawn downstream when the blade member contacts the rotational direction of the image carrier in the counter direction.
Due to this phenomenon, there is a possibility that the image carrier is damaged due to an overload applied to the motor that rotationally drives the image carrier and an excessive pressure applied to the image carrier.

In Patent Documents 2 and 3, the width of the lubricant application region is larger than the width of the cleaning blade so that the cleaning blade does not contact the surface of the image carrier in a region where the lubricant is not applied (region where the friction coefficient is high). The structure to perform is disclosed.
Patent Document 4 focuses on the fact that, in a system in which a lubricant is applied in the vicinity of the upstream side of the cleaning blade, if the lubricant is applied to an area where toner does not adhere, the lubricant becomes excessive, and the tip of the cleaning blade is the lubricant. In order to suppress damage caused by slipping through the cleaning blade, a configuration is disclosed in which the width of the cleaning blade is made larger than the width of the lubricant application region.

JP 2005-121760 A JP-A-8-292654 JP-A-11-65391 JP 2006-91415 A JP 2001-305907 A JP 2006-78853 A

As described above, in the prior art, the width setting of the cleaning blade with respect to the width of the lubricant application region differs depending on the problem to which attention is paid, and there is no suitable guideline from a comprehensive viewpoint.
In this type of cleaning unit, it is also desired to suppress wasteful consumption of the solid lubricant.
Considering the configuration described in Patent Document 4, excessive lubricant in the area where the toner does not adhere is a problem outside the image area, and even if the cleaning blade is worn out due to slipping of the lubricant in that area, it is very large. This is not a problem, and “blade turning” due to an increase in the coefficient of surface friction without applying a lubricant is much more serious.

In addition, the toner blocked by the cleaning blade may leak from the end of the blade, and the brush roller to which the lubricant is applied with this toner may become dirty with the toner over time.
As a result, a phenomenon occurs in which it becomes difficult to apply the solid lubricant to the image carrier at a position corresponding to the outer region from the end of the cleaning blade. That is, the application of the lubricant is insufficient only at the end portion described above, and the surface friction coefficient of the image carrier increases in that region, and the blade is affected by the influence.

SUMMARY An advantage of some aspects of the invention is that it provides a cleaning unit that can exhibit stable cleaning performance over a long period of time, a belt unit including the cleaning unit, and an image forming apparatus.
Another object of the present invention is to improve the cleaning property and to prevent the cleaning blade and the leveling blade from being turned up and to provide stable cleaning performance over a long period of time. To do.

To achieve the above object, according to the first aspect of the present invention, there is provided a cleaning blade for removing residual toner on the image carrier and a solid lubricant provided downstream of the cleaning blade in the moving direction of the image carrier. And an application member that is applied to the surface of the image carrier by scraping the solid lubricant (including the concept of scraping), and a lubricant that is provided downstream of the application member and applied to the image carrier by the application member In the cleaning unit having a leveling blade for leveling the agent, the width of the cleaning blade in the direction perpendicular to the moving direction of the image carrier and along the surface of the image carrier is L1, and the same as that of the coating member. When the width in the direction is L2 and the width in the same direction of the solid lubricant is L3, the widths of L1 to L3 satisfy the relationship of L1 <L3 <L2, where L1> the image forming width and Kutomo the cleaning blade is characterized in that in contact with the surface of the image bearing member in a counter direction to the moving direction of said image bearing member.

In the invention of claim 2, in the cleaning unit of claim 1, when the width of the leveling blade in the direction perpendicular to the moving direction of the image carrier and along the surface of the image carrier is L4, The widths of L1 to L4 satisfy the relationship of L4 ≦ L1 <L3 <L2, where L4> image forming width.
According to a third aspect of the present invention, in the cleaning unit according to the first or second aspect, the leveling blade is in contact with the surface of the image carrier in a counter direction with respect to a moving direction of the image carrier. It is characterized by.

According to a fourth aspect of the present invention, in the cleaning unit according to any one of the first to third aspects, the application member is a brush roller.
According to a fifth aspect of the present invention, there is provided a belt unit having an endless image bearing belt that is wound around a plurality of support members and rotates. The cleaning unit according to any one of the first to fourth aspects. It is characterized by having.

According to a sixth aspect of the present invention, in the belt unit according to the fifth aspect, a roller member is pressed from the belt surface side against the stretched region between the two support members in the entire region of the image bearing belt. The region is curved toward the inside of the belt loop, and at least a part of the cleaning unit is positioned in the curved region.
In the invention according to claim 7, in the belt unit according to claim 6, when the width of the roller member in the direction perpendicular to the moving direction of the image carrier belt and along the surface of the image carrier is L5,
L5> L3
It is characterized by satisfying the relationship.

According to an eighth aspect of the present invention, an image forming apparatus includes the belt unit according to any one of the fifth to seventh aspects.
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect, after the image formation is completed, the image carrying belt rotates in the direction opposite to the rotation direction during image formation and stops, and the next image formation is performed. It performs the operation | movement provided.
According to a tenth aspect of the present invention, in the image forming apparatus according to the eighth aspect, the application member is a brush roller, and the distance traveled by the rotation of the image carrying belt in the reverse direction is determined by the leveling blade being the image carrying belt. It is longer than the distance from the position where the coating member abuts to the position where the coating member abuts the image carrier belt.

According to an eleventh aspect of the present invention, an image forming apparatus includes the cleaning unit according to any one of the first to fourth aspects.
According to a twelfth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, after the image formation, the image carrier rotates in the direction opposite to the rotation direction during image formation and stops, and the next image formation is performed. It performs the operation | movement provided.
According to a thirteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect, the application member is a brush roller, and the distance traveled by the rotation of the image carrier in the reverse direction is determined by the leveling blade being the image carrier. The distance between the position where the coating member abuts and the position where the coating member abuts on the image carrier is longer.

According to a fourteenth aspect of the present invention, in the image forming apparatus according to any one of the eighth to thirteenth aspects, the average circularity of the toner used is 0.90 to 0.99. .
According to the fifteenth aspect of the present invention, in the image forming apparatus according to any one of the eighth to thirteenth aspects, the shape factor SF-1 of the toner used is 120 to 180, and the shape factor SF-2 is 120 to 190.
According to the sixteenth aspect of the present invention, in the image forming apparatus according to any one of the eighth to thirteenth aspects, the volume average particle diameter (μm) of the toner used is Dv, and the number average particle diameter (μm) is When Dn, Dv / Dn is 1.05-1.30.

According to the present invention, it is possible to suppress the occurrence of turning over of the cleaning blade, which has a significant effect on the image forming operation, and to obtain a stable cleaning function (and thus stable image quality) over a long period of time, as well as waste of the solid lubricant. Unnecessary consumption can be suppressed.
Further, the turning-up of the leveling blade together with the cleaning blade can be suppressed, and a stable cleaning function excellent in the lubricant application function can be obtained over a long period of time.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
First, the outline of the configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. In the figure, reference numeral 100 denotes a tandem intermediate transfer type electrophotographic apparatus main body as an image forming apparatus, and 200 denotes a paper feed table on which the main body is placed. Subscripts Y, M, C, and K indicate yellow, cyan, magenta, and black (black) colors, respectively.
The main body 100 is provided with an intermediate transfer belt 10 as an endless belt-like image bearing belt near the center. The intermediate transfer belt 10 is supported around a plurality of support rollers as support members, and rotates in the clockwise direction in the drawing.
In the drawing, a cleaning device 17 as a cleaning unit for the intermediate transfer belt is provided on the left side of the support roller 16. The cleaning device 17 removes residual toner remaining on the intermediate transfer belt 10 after image transfer.

On the intermediate transfer belt 10 stretched between the support roller 14 and the support roller 15, four image forming units 18Y, 18M, 18C of yellow, cyan, magenta, and black are arranged along the transport direction (movement direction). 18K (hereinafter abbreviated as 18Y, M, C, and K) are arranged side by side to constitute the tandem image forming apparatus 20.
An exposure device 21 is provided on the tandem image forming apparatus 20. Each image forming unit 18 of the tandem image forming apparatus 20 includes photosensitive drums 40Y, 40M, 40C, and 40K as image carriers that carry yellow, cyan, magenta, and black color toner images.

At the primary transfer position where the toner image is transferred from the photosensitive drums 40Y, 40M, 40C, and 40K to the intermediate transfer belt 10, the photosensitive drums 40Y, 40M, 40C, and 40K are opposed to each other with the intermediate transfer belt 10 interposed therebetween. As described above, primary transfer rollers 62Y, 62M, 62C, and 62K are provided as components of the primary transfer unit.
The support roller 14 is a drive roller that rotationally drives the intermediate transfer belt 10. When a black monochrome image is formed on the intermediate transfer belt 10, the support rollers 15 and 15 ′ other than the driving roller are moved to separate the yellow, cyan, and magenta photoconductors 40 Y, M, and C from the intermediate transfer belt 10. It is also possible to make it.
The present invention is not limited to the tandem type as in this embodiment, and can be applied to an apparatus having only one photoconductor.

A secondary transfer device 22 is provided on the opposite side of the intermediate transfer belt 10 from the tandem image forming device 20. In the illustrated example, the secondary transfer device 22 presses the secondary transfer roller 16 'against the secondary transfer counter roller 16 to apply a transfer electric field, thereby transferring the image on the intermediate transfer body 10 to a sheet (not shown) as transfer paper. Transcript.
A fixing device 25 for fixing the transfer image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 has a configuration in which a pressure roller 27 is pressed against a fixing belt 26 that is an endless belt.
The sheet after image transfer is conveyed to the fixing device 25 by the conveyance belt 24. Instead of the conveyor belt 24, it may be conveyed by a fixed guide member.
Under the secondary transfer device 22 and the fixing device 25, a sheet reversing device 28 for reversing the sheet so as to record images on both sides of the sheet is provided substantially parallel to the tandem image forming device 20.

When image data is sent to the image forming apparatus 100 and an image formation start signal is received, the support roller 14 is driven to rotate by a drive motor (not shown), the other plurality of support rows are driven to rotate, and the intermediate transfer belt 10 is rotated. Rotate.
At the same time, a single color image of yellow, cyan, magenta, and black is formed on each photoconductor 40 by the individual image forming means 18. As the intermediate transfer belt 10 moves, the monochrome images are sequentially transferred by the transfer unit 62 to form a composite color image on the intermediate transfer member 10.
Further, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, the sheets are fed out from one of the paper cassettes 44 provided in multiple stages in the paper bank 43, and are separated one by one by the separation roller 45 and fed. The paper is put into a path 46, transported by a transport roller 47, led to a paper feed path 48 in the copying machine main body 100, and abutted against a registration roller 49 and stopped.

Alternatively, the sheet feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 10, the sheet is fed between the intermediate transfer belt 10 and the secondary transfer device 22, and transferred by the secondary transfer device 22. A color image is recorded on the sheet.

The sheet after the image transfer is conveyed by the secondary transfer device 22 and sent to the fixing device 25, the transfer image is fixed by applying heat and pressure, and then discharged by the discharge roller 56. Stacked on top. Alternatively, the sheet is switched by a switching claw (not shown) and put into the sheet reversing device 28, where it is reversed and guided to the transfer position again. Discharged.
On the other hand, the intermediate transfer belt 10 after the image transfer is removed by the intermediate transfer belt cleaning device 17 to remove residual toner remaining on the intermediate transfer belt 10 after the image transfer, so that the tandem image forming apparatus 20 can form an image again. Prepare.
The intermediate transfer belt 10, the support rollers 14, 15, 15 ′, 16 and the cleaning device 17 constitute a belt unit 70 according to this embodiment.

The configuration of the cleaning device 17 will be described with reference to FIG.
The cleaning device 17 has a cleaning blade 103 that contacts the surface of the intermediate transfer belt 10 with an elastic force in the counter direction to remove residual toner. The cleaning blade 103 has a proximal end fixed to a support bracket 116 that is rotatably supported by a cleaning base 114 via a shaft 115. A spring 109 is stretched between the other end of the support bracket 116 and the cleaning base 114.
A paper dust removing roller 102 is provided upstream of the cleaning blade 103 in the moving direction of the intermediate transfer belt 10 (in the direction of arrow A), and is removed by the residual toner removed by the cleaning blade 103 and the paper dust removing roller 102. The collected paper dust is collected by the collection coil 106.

On the downstream side of the cleaning blade 103, there are provided a block or bar-shaped solid lubricant 107 and a brush roller 104 as an application member that scrapes the solid lubricant 107 and supplies it to the surface of the intermediate transfer belt 10.
The solid lubricant 107 is accommodated in a holder 117 fixed to the cleaning base 114, and is urged toward the brush roller 104 by a spring 108.
On the downstream side of the brush roller 104, a leveling blade 105 for uniformly distributing the lubricant supplied by the brush roller 104 onto the intermediate transfer belt 10 is disposed. The leveling blade 105 is in contact with the surface of the intermediate transfer belt 10 by an elastic force in the counter direction.

Like the cleaning blade 103, the leveling blade 105 is fixed at a base end to a support bracket 119 that is rotatably supported by a cleaning base 114 via a shaft 118. A spring 110 is stretched between the other end of the support bracket 119 and the cleaning base 114.
A counter roller 111 for enhancing the removal function is disposed at a portion inside the intermediate transfer belt 10 facing the cleaning blade 103 and the paper dust removing roller 102.
Similarly, a counter roller 112 for enhancing the application function and the leveling function is disposed at a portion inside the intermediate transfer belt 10 facing the leveling blade 105 and the brush roller 104.

The brush roller 104 for applying the lubricant is rotationally driven in a direction that rotates in the rotational direction of the intermediate transfer belt 10. However, the present invention can be applied even when the brush roller 104 is rotationally driven in the counter direction with respect to the rotational direction of the intermediate transfer belt 10. The effect of can be demonstrated.
However, when the former rotates in the direction of rotation, the brush roller 104 is less damaged, and can be used for a longer period of time.
The leveling blade 105 is in contact with the intermediate transfer belt 10 in the counter direction, but may be in contact with a trailing (forward direction) system. When the contact is made in the counter direction, a function that complements the removal function of the cleaning blade 103 can be provided.

By making the contact of the cleaning blade 103 a counter direction with respect to the rotation direction of the intermediate transfer belt 10, a high cleaning property can be exhibited. In the present embodiment, the cleaning blade 103 and the leveling blade 105 are both brought into counter contact with each other to form a cleaning device that is excellent in toner removal, more reliable, and highly durable.
As the material of the cleaning blade 103, urethane rubber having a rebound resilience (K6301 Rupke type) of 17 and a hardness (K6301 JIS-A) of about 70 is used.
The blade properties that can be employed in the present invention are shown below.
Hardness: 60 to 80 (according to JIS-A k6301), preferably about 70 Young's modulus: 3 to 10 MPa, preferably about 6 to 7 MPa Rebound resilience: 10 to 80 (K6301 Rupke type), preferably about 20

  If the same level of member is used for the leveling blade 105, the leveling blade 105 can clean the toner even if the toner slips through the cleaning blade 103. Even if the width of the cleaning blade 103 and the leveling blade 105 is the same, the effect of the present invention can be exhibited.

The width of the cleaning blade 103 and the like will be described with reference to FIG. Here, the “width” is the width in the direction perpendicular to the moving direction of the intermediate transfer belt 10 and along the surface of the intermediate transfer belt 10, in other words, the width in the width direction of the sheet perpendicular to the sheet conveyance direction ( same as below).
When the width of the cleaning blade 103 is L3, the width of the brush roller 104 is L2, the width of the solid lubricant 107 is L3, and the width of the leveling blade 105 is L4, the widths of L1 to L3 are L4 ≦ L1 <L3 <L2 However, it is set so as to satisfy the relationship of L4> image forming width.

By making the width L3 of the solid lubricant 107 wider than the width L1 of the cleaning blade 103, the friction coefficient of the surface of the intermediate transfer belt 10 corresponding to the entire width region of the cleaning blade 103 can be kept low. Thereby, generation | occurrence | production of the blade turning from the edge part of the cleaning blade 103 can be prevented.
At this time, by setting the width L2 of the brush roller 104 to L3 <L2, the entire region of the solid lubricant 107 can be scraped by the brush roller 104, so that the lubricant can be consumed without waste.

In addition, the toner blocked by the cleaning blade may leak from the end of the blade, and the brush roller to which the lubricant is applied with this toner may become dirty with the toner over time. As a result, a phenomenon occurs in which it becomes difficult to apply the solid lubricant to the image carrier at a position corresponding to the outer region from the end of the cleaning blade.
In this case, the lubricant is insufficiently applied only to the end portion of the brush roller, and the surface friction coefficient of the image carrier increases in that region, and when the leveling blade is in contact with the counter, the leveling blade is turned over. cause.

In order to deal with this problem, in this embodiment, the relationship is L4 ≦ L1. By doing so, the leveling blade 105 can function stably without being affected by insufficient application of the lubricant due to the toner leaking from the end of the cleaning blade 103.
In this embodiment, the width of the leveling blade 105 is narrower than the width of the cleaning blade 103, and the difference m between the cleaning blade 103 at both ends is set to 2 to 3 mm.
Therefore, by setting the width of each member in the cleaning device 17 as described above, the cleaning performance is improved, and the cleaning blade 103 and the leveling blade 105 are not turned up, and stable cleaning performance is achieved for a long time. It can be exhibited over a wide range.
Even when L1 <L3 <L2 is set so as to satisfy L1> image forming width, the cleaning blade 103 can be prevented from being turned over, and wasteful consumption of the lubricant can be eliminated.

  In general, in an image forming apparatus that forms a full color image by superimposing a plurality of colors, the cleaning load is higher than in the case of mono-color, and the problem is how to extend the life of the cleaning apparatus. By providing the full-color image forming apparatus with the cleaning device 17 according to the present embodiment, it is possible to provide full-color print quality free from image defects due to cleaning defects or the like over a long period of time.

  After the image formation is completed (after the secondary transfer is completed), the reverse operation as shown in FIG. 3 is performed. As a result, foreign matters such as paper dust adhered to the edge of the cleaning blade 103 are removed, and the lubricant accumulated on the edge of the leveling blade 105 is removed, and the edge can be refreshed before the next image formation. it can. As a result, poor cleaning due to the inclusion of foreign matter is prevented, and the lubricant accumulates at the edge of the leveling blade 105, so that leveling unevenness does not occur.

If left for a long time after completion of image formation, the lubricant accumulated on the edge of the leveling blade 105 may stick to the edge in a hardened state. As a result, the leveling unevenness of the lubricant may occur. Therefore, it is desirable that the edge of the leveling blade 105 be refreshed as much as possible before image formation.
Although the edge portion can be refreshed to some extent simply by reversing, in this embodiment, in order to pulverize the lubricant accumulated on the edge of the smoothing blade 105, the travel distance by the reverse rotation is determined by the smoothing blade 105. The distance is set longer than the distance from the position where the brush roller 104 contacts the intermediate transfer belt 10 to the position where the brush roller 104 contacts the intermediate transfer belt 10.

By doing so, the lubricant accumulated at the edge of the leveling blade 105 returns to the position of the brush roller 104, and the lubricant is pulverized between the brush roller 104 and the intermediate transfer belt 10. As a result, the lubricant can be reliably prevented from entering the edge again as a lump.
Immediately after the intermediate transfer belt 10 is stopped, a belt drive motor (not shown) is not reversed, but is reversely rotated with a stop time t. This stop time t is a time for avoiding problems such as a surge voltage of the belt drive motor.

As shown in FIG. 2, the belt unit 70 is located downstream of the cleaning device 17 with respect to the stretched region between the two stretching members (support rollers 15 ′ and 16) in the entire region of the intermediate transfer belt 10. Thus, a roller member 63 pressed from the outside of the intermediate transfer belt 10 is disposed, thereby securing a space for installing the cleaning device 17.
It is possible to save space by pressing from the surface side of the intermediate transfer belt 10 to curve the stretched region toward the belt loop inner side, and positioning at least a part of the cleaning device 17 in the curved region. , Can increase the degree of design freedom.

As shown in FIG. 4, when the contact area width of the roller member 63 pressed from the belt surface to the intermediate transfer belt 10 is L5,
L5> L3
It is set to satisfy the relationship.
Since the relationship between the width L3 of the solid lubricant 107 and the width L4 of the leveling blade 105 located downstream of the solid lubricant 107 is L3> L4 as described above, the lubricant is not leveled on the side of the leveling blade 105. In this state, the intermediate transfer belt 10 is conveyed.
Since the powdery lubricant is only on the belt in that region, the lubricant on the belt may scatter during long-term use, thereby causing contamination of the device.
Therefore, it becomes necessary to provide a cover or the like that was originally unnecessary for the motor and the electrical parts.

Here, when L5> L3, by pressing the roller member 63 from the front side of the belt against the entire area where the lubricant is applied, the powdery lubricant adhering to the side of the leveling blade 105 is placed on the belt. By pressing, it is possible to prevent the lubricant from splashing unnecessarily.
In other words, since the roller member 63 is set wider than the width of the solid lubricant 107, the lubricant is prevented from scattering from the end region of the intermediate transfer belt 10 outside the region of the leveling blade 105. The

The tension of the intermediate transfer belt 10 is 0.5 N / cm to 3 N / cm, preferably 1 to 2 N / cm.
As an example of the material (substance having self-lubricating property) of the solid lubricant 107, the following organic organic materials include stable metal salts of fatty acids.
Typical fatty acids from which stable hydrophobic metal salts are removed include caproic acid, caprylic acid, enanthylic acid, pelargonic acid, undecylic acid, lauric acid, tridecoic acid, myristylic acid, palmitic acid, margaric acid, stearic acid, Non-cyclic acid, arachidic acid, behenic acid, styringinic acid, palmitoleic acid, oleic acid, ricinoleic acid, petellocerinic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, ricinic acid, valinalic acid, gardoleic acid, arachidone There are acids, whale oil and mixtures thereof.
Typical stable metal salts of fatty acids include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate , Zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, palmitate Aluminum oxide, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate and mixtures thereof There is a thing, but is not limited to this.
Examples of inorganic substances include, but are not limited to, boron nitride, graphite, boron carbide, molybdenum disulfide, lead oxide, calcium fluoride, and ceramics.

The force that presses the intermediate transfer belt 10 with the leveling blade 105 is sufficient as the solid lubricant 107 extends to form a protective layer or a protective film, and the linear pressure is 5 gf / cm or more and 80 gf / cm or less. It is preferably 10 gf / cm or more and 60 gf / cm or less.
The brush-like member (brush roller 104) is preferably used as a solid lubricant supply member. In this case, the brush fiber has flexibility in order to suppress mechanical stress on the surface of the image carrier. Is preferred.
As a specific material of the flexible brush fiber, one or more kinds can be selected and used from generally known materials. Specifically, polyolefin resins (eg, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (eg, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and Polyvinyl chloride); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene-butadiene resin; fluorine resin (for example, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); Polyester; Nylon; Acrylic; Rayon; Polyurethane; Polycarbonate; Phenol resin; Amino resin (eg urea-formaldehyde resin, melamine) Fat, benzoguanamine resins, urea resins, polyamide resins); Among such, may be a resin having flexibility.

Also, in order to adjust the degree of bending, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. are used in combination. Also good.
The brush fiber has a fiber diameter of about 10 to 500 μm, the length of the brush fiber is 1 to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ^{7 to} 4.5 × 10 per square meter). ⁸ ) are preferably used.
The brush roller 104 is preferably made of a material having as high a brush density as possible from the viewpoint of supply uniformity and stability, and it is also preferable to make one fiber from several to several hundreds of fine fibers. . For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

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

Hereinafter, the toner suitably used in the present invention will be described.
(Circularity and circularity distribution)
It is important that the toner in the present invention has a specific shape and shape distribution. An toner having an average circularity of less than 0.90 and an irregular shape that is too far from a spherical shape exhibits satisfactory transferability and dust. A high-quality image with no image cannot be obtained.
As a method for measuring the shape, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. Toner having an average circularity of 0.90 to 0.99, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle, has high reproducibility with an appropriate density reproducibility. It was found to be effective for forming a clear image.

More preferably, particles having an average circularity of 0.93 to 0.97 and a circularity of less than 0.94 are 10% or less. When the average circularity exceeds 0.99, in a system that employs blade cleaning or the like, poor cleaning occurs on the photosensitive member and the transfer belt, causing stains on the image.
For example, when outputting an image with a low image area ratio, there is little transfer residual toner and there is no problem with poor cleaning. However, when outputting an image with a high image area ratio such as a color photographic image, If an untransferred image remains on the photoreceptor due to a defect or the like, a cleaning defect is likely to occur. If the above-mentioned cleaning failures occur frequently, further, the charging roller that contacts and charges the photoreceptor is contaminated, and the original charging ability cannot be exhibited.

(Measurement method of circularity)
The average circularity can be measured by a flow type particle image analyzer FPIA-2100 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is obtained by performing dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

(Shape factors SF-1 and SF-2)
As shown in FIG. 6, the shape factor SF-1 here is a value indicating the ratio of the roundness of the shape of the spherical substance, and is the maximum of the elliptical figure formed by projecting the spherical substance on a two-dimensional plane. It is represented by a value obtained by dividing the square of the length MXLNG by the graphic area AREA and multiplying by 100π / 4. That is, the shape factor SF-1 is expressed by the following equation:
SF-1 = {(MXLNG) ² / AREA} × (100π / 4)
Is defined by
When the value of SF-1 is 100, the shape of the substance becomes a true sphere, and as the value of SF-1 increases, the shape of the substance becomes indefinite.

Further, as shown in FIG. 7, the shape factor SF-2 is a numerical value indicating the ratio of the unevenness of the shape of the substance, and the square of the perimeter PERI of the figure formed by projecting the substance on the two-dimensional plane is the figure area. It is expressed as a value when divided by AREA and multiplied by 100 / 4π. That is, the shape factor SF-2 is expressed by the following equation:
SF-2 = {(PERI) ² / AREA} × (100 / 4π).
When the value of SF-2 is 100, there is no unevenness on the surface of the substance, and as the value of SF-2 increases, the unevenness on the surface of the substance becomes more prominent.

In the embodiment of the present invention, a toner image is randomly sampled 100 times using an FE-SEM (S-800) manufactured by Hitachi, and the image information is stored in an image analysis apparatus (LUSEX3) manufactured by Nireco. Introduced and analyzed, calculated from the above formula.
It has been clarified by the present inventors that the transfer efficiency increases when the toner shape approaches the spherical shape as much as possible (both SF-1 and SF-2 approach 100). This is because there is only point contact between the toner particles and the ones that contact the toner particles (toner particles, image carrier, etc.) due to the shape effect, so that the toner fluidity is increased or the toner is adsorbed to the image carrier, etc. This is thought to be because the force (mirror power) is weakened and is easily affected by the transfer electric field.
On the other hand, when the shape of the toner approaches a spherical shape, it is disadvantageous for mechanical cleaning (such as blade cleaning).
As described above, this is because the toner fluidity is increased and the adsorbing force (mirroring force) on the image carrier is weakened so that the toner can easily pass through the slight gap between the cleaning member and the image carrier. End up. Therefore, from the viewpoint of cleaning properties, the shape of the toner is somewhat irregular (in the direction in which the value of SF-1 is greater than 100) or uneven (in the direction in which the value of SF-2 is greater than 100). It is more preferable.

(Dv / Dn (ratio of volume average particle diameter / number average particle diameter))
Dv / Dn is one of the parameters representing the toner particle size distribution.
The volume average particle diameter (Dv) of the toner is 4 to 8 μm, and the ratio (Dv / Dn) to the number average particle diameter (Dn) is 1.05 to 1.30, preferably 1.10 to 1.25. According to a certain dry toner, the toner particle size distribution becomes narrow, and the following merits occur.
A stable image can be formed at all times because a phenomenon such as selective development on the toner particle size surface (toner particles having a (suitable) toner particle size corresponding to the image pattern are selectively developed) hardly occurs. Can do.
When a toner recycling system is mounted, a large amount of small-size toner particles that are difficult to transfer are recycled in quantity. However, since the toner particle size distribution is originally narrow, it is difficult to receive the above-mentioned action. Therefore, a stable image can always be formed.

In a two-component developer, even if a long-term balance of the toner is performed, fluctuations in the toner particle diameter in the developer are reduced, and good and stable developability can be obtained even with long-term stirring in the developing device. .
Even when used as a one-component developer, even if the balance of the toner is performed, the fluctuation of the toner particle diameter is reduced, the filming of the toner on the developing roller, and a blade for thinning the toner The toner was not fused to a member such as the above, and good and stable developability and an image were obtained even in the long-term use (stirring) of the developing device.

In general, it is said that the smaller the particle size of the toner, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning properties. is there. Further, when the volume average particle diameter is smaller than the range of the present invention, in the case of the two-component developer, the toner is fused to the surface of the carrier during a long period of stirring in the developing device, and the charging ability of the carrier is reduced, or the one-component development is performed. When used as an agent, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur.
Further, these phenomena are the same for the toner having a fine powder content larger than the range of the present invention.

On the contrary, when the particle diameter of the toner is larger than the range of the present invention, it becomes difficult to obtain a high resolution and high quality image, and when the balance of the toner in the developer is performed, In many cases, the variation of the particle size becomes large. It was also clarified that the same applies when the volume average particle diameter / number average particle diameter is larger than 1.30.
Further, when the volume average particle diameter / number average particle diameter is smaller than 1.05, there is a preferable aspect from the viewpoint of stabilizing the behavior of the toner and uniforming the charge amount, but the thin line portion is developed with small size particles. On the other hand, it is difficult to separate the functions depending on the toner particle diameter, such as developing a solid image mainly on large-size particles, which is not preferable.

(Measurement method related to toner particle size)
Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used.
Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated.
From the obtained distribution, the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner can be obtained. As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  In the above embodiment, the intermediate transfer belt is exemplified as the image carrier. However, the present invention can be similarly applied to the photosensitive drum.

It is an expanded view which shows the width relationship of elements, such as a cleaning blade, in the cleaning unit which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the cleaning unit in a belt unit. 6 is a timing chart when the image bearing belt is rotated in reverse. FIG. 5 is a development view showing a width relationship between an element such as a cleaning blade in the cleaning unit and a roller member that presses the belt unit. 1 is a schematic sectional view of an image forming apparatus. FIG. 6 is a schematic diagram of a toner shape for explaining a shape factor SF-1. FIG. 6 is a schematic diagram of a toner shape for explaining a shape factor SF-2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Intermediate transfer belt as image carrier and image carrier belt 14, 15, 15 ′, 16 Support roller as support member 17 Cleaning device 63 Roller member 70 Belt unit 103 Cleaning blade 104 Brush roller 105 as application member Blade 107 Solid lubricant

Claims (16)

A cleaning blade for removing residual toner on the image carrier, a solid lubricant provided downstream of the cleaning blade in the moving direction of the image carrier, and the solid lubricant are scraped off and applied to the surface of the image carrier. A cleaning unit having a coating member to be applied and a leveling blade provided downstream of the coating member for leveling the lubricant applied to the image carrier by the coating member;
The width of the cleaning blade in the direction perpendicular to the moving direction of the image carrier and along the surface of the image carrier is L1, the width of the coating member in the same direction is L2, and the width of the solid lubricant in the same direction. When L3, the width of L1 to L3 satisfies the relationship of L1 <L3 <L2, where L1> the image forming width, and at least the cleaning blade is in the counter direction with respect to the moving direction of the image carrier. A cleaning unit which is in contact with the surface of an image carrier. The cleaning unit according to claim 1, wherein
When the width of the leveling blade in the direction perpendicular to the moving direction of the image carrier and along the surface of the image carrier is L4, the width of L1 to L4 is L4 ≦ L1 <L3 <L2, where L4>. A cleaning unit that satisfies the relationship of image forming width. The cleaning unit according to claim 1 or 2,
The cleaning unit, wherein the leveling blade is in contact with the surface of the image carrier in a counter direction with respect to the moving direction of the image carrier. In the cleaning unit according to any one of claims 1 to 3,
The cleaning unit, wherein the application member is a brush roller. In a belt unit having an endless image bearing belt that is wound around a plurality of support members and rotates.
A belt unit comprising the cleaning unit according to claim 1. The belt unit according to claim 5, wherein
Of the entire area of the image bearing belt, a roller member is pressed from the belt surface side against the stretched area between the two support members to curve the stretched area toward the inside of the belt loop, and within the curved area. A belt unit comprising at least a part of the cleaning unit. The belt unit according to claim 6, wherein
When the width of the roller member in the direction perpendicular to the moving direction of the image carrier belt and along the surface of the image carrier is L5,
L5> L3
A belt unit characterized by satisfying the relationship.   An image forming apparatus comprising the belt unit according to claim 5. The image forming apparatus according to claim 8.
An image forming apparatus, wherein the image carrying belt rotates and stops in a direction opposite to a rotation direction during image formation after image formation is completed, and performs an operation for preparing for the next image formation. The image forming apparatus according to claim 8.
The application member is a brush roller, and the moving distance of the image carrier belt by rotating in the reverse direction is a position where the application member contacts the image carrier belt from a position where the leveling blade contacts the image carrier belt. The image forming apparatus is characterized in that it is longer than the distance up to.   An image forming apparatus comprising the cleaning unit according to claim 1. The image forming apparatus according to claim 11.
An image forming apparatus, wherein the image carrier rotates in a direction opposite to a rotation direction during image formation and stops after image formation is completed, and performs an operation for preparing for the next image formation. The image forming apparatus according to claim 12.
The application member is a brush roller, and the moving distance by the reverse rotation of the image carrier is a position at which the application member contacts the image carrier from a position at which the leveling blade contacts the image carrier. The image forming apparatus is characterized in that it is longer than the distance up to. The image forming apparatus according to any one of claims 8 to 13,
An image forming apparatus having an average circularity of a toner used of 0.90 to 0.99. The image forming apparatus according to any one of claims 8 to 13,
An image forming apparatus, wherein the toner has a shape factor SF-1 of 120 to 180 and a shape factor SF-2 of 120 to 190. The image forming apparatus according to any one of claims 8 to 13,
An image forming apparatus, wherein Dv / Dn is 1.05 to 1.30, where Dv is a volume average particle diameter (μm) of a toner to be used and Dn is a number average particle diameter (μm).

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