JP2006251362A - Cleaning device and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain an initial contact state by a cleaning member for a long period and to improve the maintaining characteristic of a member to be cleaned by effectively preventing the wear of the cleaning member. <P>SOLUTION: The cleaning device 3 for cleaning image formation particles 2 remaining on an image conveyance object 1 is equipped with the cleaning member 4 which comes into contact with the image conveyance object 1 and in which the contact section shape with the image conveyance object 1 is held in a non-deformed state regardless of the stoppage in the movement of the image conveyance object, and a moving mechanism 7 which makes the cleaning member 4 freely movable along the direction crossing the moving direction of the image conveyance object 1. The cleaning member 4 is equipped with a plate-like base substrate 5 and a coating layer 6 coating a portion corresponding to at least a contact part with the image conveyance object 1 of the base substrate 5 and satisfies the conditions; (a). the Vickers hardness to be ≥1,500 Hv: (b). the coefficient of friction of the surface to be smaller than the coefficient of friction of the base substrate 5 before the coating; and (c). the surface roughness to be below the surface roughness of the base substrate 5 before the coating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning device that is used in an image forming apparatus such as a copying machine or a printer and that cleans image-forming particles remaining on an image carrier, and in particular, a metal scraper that contacts the image carrier. The present invention relates to a cleaning device having a cleaning member whose contact portion shape is not deformed, an image forming apparatus using the cleaning device, and an improvement of the cleaning member.

In general, in an image forming apparatus such as a copying machine or a printer, for example, an electrophotographic method is used to clean toner that is image forming particles remaining on the surface of an image carrier such as a photosensitive drum or an intermediate transfer belt. A device is provided.
As this type of cleaning device, for example, an elastic blade such as urethane rubber is brought into contact with the surface of the image carrier to scrape residual toner on the image carrier.
By the way, in recent years, small-diameter toner has been used in order to increase the resolution of an image formed by an image forming apparatus. In particular, among small-diameter toners, for example, small-diameter polymerized toners produced by a polymerization method are being used widely because they are spherical and advantageous in terms of ease of production.

In a system using such a small-diameter polymerized toner, when the cleaning device using the above-described elastic blade is used, it may be difficult to ensure a good cleaning property against the toner having a small diameter and a spherical shape. It was found.
In other words, when cleaning is performed using an elastic blade, the pressing force of the elastic blade against the image carrier must be set large by reducing the diameter or sphere of the toner. As a result, the coefficient of friction with the image carrier increases, and accordingly, a high rotational torque is required to stably rotate the image carrier, which increases the cost of the drive source and deforms the tip shape of the elastic blade. In particular, when the toner is spheroidized, there is a concern that the toner slips through the tip of the elastic blade and the cleaning property is remarkably deteriorated, and there is a technical problem that the tip of the elastic blade is easily damaged.

  In order to solve such a technical problem, for example, a metal scraper (for example, made of SUS) as a cleaning member is brought into contact with the surface of the image carrier to clean the residual toner on the image carrier. (See, for example, Patent Document 1).

JP 2003-112129 A (column of embodiment of the invention, FIG. 2) JP-A-2004-286888 (column of embodiment of the invention, FIG. 3)

Certainly, when using a metal scraper as a cleaning member, the tip edge portion of the metal scraper reliably contacts the surface of the image carrier due to the spring nature of the metal, compared to an elastic blade such as urethane rubber. It was confirmed that the cleaning performance for small-diameter polymerized toner at the beginning of use dramatically improved.
However, if the metal scraper is used for a long period of time, due to the wear of the metal scraper, the image carrier as the member to be cleaned and the metal scraper come into surface contact, and the cleaning performance gradually deteriorates over time. It was.

In order to solve such a technical problem, in Patent Document 1, a metal scraper that is in contact with an image carrier is held by a scraper holding adjustment device, and an installation angle of the metal scraper is increased with time. Technology has been proposed.
However, providing such a scraper holding and adjusting device is not preferable in terms of cost and space, and the scraper holding and adjusting device is configured to change the installation angle of the metal scraper. There is a concern that the cleaning performance of the metal scraper will change as much as the contact pressure of the scraper changes, and there is a concern that it cannot be handled when the wear amount of the metal scraper is larger than the predicted wear amount. There is also.

  The present invention has been made to solve the above technical problems, and effectively prevents the cleaning member from being worn, maintains the initial contact state by the cleaning member for a long period of time, and provides high cleaning performance. In addition, the present invention provides a cleaning device capable of improving the maintainability of a member to be cleaned, an image forming apparatus using the same, and a cleaning member.

  That is, according to the present invention, as shown in FIG. 1A, in a cleaning device 3 that cleans image forming particles 2 remaining on the image carrier 1, the image carrier 1 comes into contact with the image carrier 1. The cleaning member 4 whose contact portion shape is kept in an undeformed state regardless of the movement stop of the image carrier 1 and the movement that allows the cleaning member 4 to move along the direction intersecting the moving direction of the image carrier 1. The cleaning member 4 includes a plate-like base substrate 5 and a coating layer 6 that covers at least a portion of the base substrate 5 corresponding to the contact portion with the image carrier 1. A. Vickers hardness is 1500 Hv or more, b. The surface friction coefficient is smaller than the friction coefficient of the base substrate 5 before coating; c. It is characterized by satisfy | filling that the surface roughness is below the surface roughness of the base base material 5 before coating | covering.

In such technical means, the image carrier 1 to be cleaned by the cleaning device 3 supports the visible image indirectly through the recording material as well as the image carrier directly supporting the visible image. Also includes a recording material carrier. Further, the image carrier 1 includes a transfer carrier (transfer roll or the like) or a fixing carrier (fixing roll, fixing belt or the like), which is a member for conveying an image.
In addition, the cleaning member 4 of the present case is a contact type that contacts the image carrier 1, and the shape of the contact portion with the image carrier 1 is maintained in an undeformed state regardless of the movement of the image carrier 1 being stopped. As a typical example, a metal scraper using a metal base substrate 5 may be used, but the present invention is not limited to this. For example, a base material 5 made of hard resin or ceramics may be used. There may be.
Further, examples of the cleaning member 4 include a mode in which the residual image forming particles 2 are scraped by a contact type, but are not limited to this, and include a mode having both “scraping function + charging function”. . Furthermore, the cleaning member 4 may be used in a single manner or a plurality of cleaning members 4 or may be arranged in parallel, or other cleaning members (elastic blade, electrostatically adsorbable cleaning roll, cleaning brush, etc.) You may make it combine with.

Further, the covering layer 6 may cover the entire base substrate 5, but it is necessary to cover at least a portion of the base substrate 5 corresponding to the contact portion with the image carrier 1. It is.
And the coating layer 6 needs to satisfy | fill the conditions (a. Hardness conditions, b. Friction coefficient conditions, c. Surface roughness conditions) mentioned above. Here, the hardness condition is selected based on the Vickers hardness, but the friction coefficient is small in relation to the base substrate 5 before coating, and the surface roughness is the same as that of the base substrate 5 before coating. As long as they are the same or smaller in relation, the types (friction coefficient: static friction coefficient, dynamic friction coefficient, etc., surface roughness: average surface roughness, ten-point average surface roughness, etc.) It does not matter if it is selected as appropriate.
If the hardness condition and the surface roughness condition are satisfied, the wear amount of the cleaning member 4 can be reduced by reducing the surface roughness with high hardness.
If the friction coefficient condition is satisfied, by reducing the friction coefficient, it is possible to reduce the wear amount and damage of the image carrier 1 that is a member to be cleaned.

In addition, as an aspect applicable as the coating layer 6, a diamond-like carbon film (DLC [abbreviation of Diamond Like Carbon] film), a cubic boron nitride film (C-BN film), a silicon carbide film (SiC film), nitriding There is an embodiment in which at least one of a chromium film (CrN film), a tungsten carbon film (WC film), and a ta-C film (Tetrahedral Amorphous Carbon film) is included.
In particular, since the DLC film is very good in terms of hardness, friction coefficient, and surface roughness, it is preferable that the coating layer 6 is a DLC film as a surface layer.
Furthermore, the coating layer 6 may be a single layer, but the surface layer 6a preferably has a laminated structure with the highest hardness. In this case, an intermediate layer 6b is interposed between the surface layer 6a and the base substrate 5. The intermediate layer 6b may be a single layer or a plurality of laminated layers, and the function of the intermediate layer 6b includes, for example, an aspect in which adhesion (adhesion) between the surface layer 6a and the base substrate 5 is ensured. . In particular, when the base substrate 5 is a metal, the crystal structure between the surface layer 6a and the surface layer 6a is often greatly different, and it is preferable to interpose this kind of intermediate layer 6b.

As a prior art approximated to this kind of coating layer, there is an invention described in Patent Document 2, but this prior art is supplemented just in case that it is irrelevant to the present invention.
In other words, the cleaning member 4 of the present invention is such that the shape of the contact portion with the image carrier 1 is kept in an undeformed state regardless of the movement of the image carrier 1 being stopped, and the plate-like base substrate that is not locally deformed. For example, a DLC film or the like is formed on 5. According to this aspect, since the tip of the cleaning member 4 is not elastically deformed, the coating layer 6 does not move relative to the base substrate 5, and the coating layer 6 has sufficient characteristics such as high hardness, low friction and smoothness. It is alive.
On the other hand, the cleaning member of the prior art is based on the premise of an elastic blade, and a coating layer such as DLC is formed on the elastic base substrate of this elastic blade.
For this reason, in this aspect, since the contact portion of the cleaning member with respect to the photosensitive drum or the like is elastically deformed, the coating layer cannot follow the deformation of the elastic base member, and the elastic base member is covered with the coating layer. However, the tip of the cleaning member is broken, for example, a crack occurs in the coating layer.
Thus, the present invention is completely different from the invention described in Prior Literature 2.

Furthermore, as shown in FIG. 1B, the present invention only needs to include a moving mechanism 7 for the cleaning member 4, and the moving mechanism 7 intersects with the moving direction of the image carrier 1 (at least the moving). The cleaning member 4 may be appropriately selected as long as the cleaning member 4 is movable along the direction having a directional component perpendicular to the direction.
Here, the moving mechanism 7 may be any mechanism as long as the contact position of the cleaning member 4 with respect to the image carrier 1 is variable along the crossing direction, and the cleaning member 4 may be moved freely. Alternatively, the cleaning member 4 may be forcibly moved by providing a drive mechanism.

In addition, as an aspect in which the cleaning device 3 according to the present invention is effective, there is an aspect in which the image forming particle 2 is a toner having a shape factor of 140 or less or a toner having a volume average particle diameter of 3 to 9 μm. It is done. As described above, in the aspect in which the image forming particle 2 is a spherical toner or the aspect in which the image forming particle 2 is a small-diameter toner, it is necessary to use the cleaning member 4 having a non-deformable contact portion shape. It is effective for.
Furthermore, the image carrier 1 to be cleaned is not limited to a rigid body but may be an elastic body. In the present invention, since the frictional force between the cleaning member 4 and the elastic image carrier 1 can be greatly reduced by devising the configuration of the cleaning member 4, the shape of the contact portion is not deformed with respect to the elastic image carrier 1 as well. The cleaning member 4 can be employed.

Further, the present invention is not limited to the cleaning device 3 described above, but also targets an image forming apparatus using the same.
In this case, the present invention includes an image carrier 1 on which a visible image by the image-forming particles 2 is conveyed, and the above-described cleaning device 3 that cleans the image-forming particles 2 remaining on the image carrier 1. Just do it.
In this type of image forming apparatus, as shown in FIG. 2, the image carrier 1 includes an image forming carrier 1a that forms and carries a visible image, and an image carrier 1b that is disposed to face the image forming carrier 1b. The image forming carrier 1a and the image transporting carrier 1b are each provided with a cleaning device 3 (specifically 3a, 3b). Specifically, it is preferable to provide 4a and 4b). Since the friction coefficient of the cleaning member 4 of the present case hardly changes depending on the member to be cleaned, the cleaning member 4 can be used in common.
Here, the image carrying carrier 1b is disposed opposite to the image forming carrier 1a, and includes both an intermediate transfer member and a recording material carrier. Now, in the embodiment in which the image carrying carrier 1b is an intermediate transfer member, as shown in FIG. 2, the image on the image forming carrier 1a is primarily transferred to the image carrying carrier 1b by the primary transfer means 8a. The image on the image carrier 1b may be secondarily transferred to the recording material 9 by the secondary transfer means 8b.

According to the cleaning device of the present invention, the surface of the cleaning member whose shape of the contact portion with the image carrier is not deformed is provided with a high hardness, low friction, and a smooth coating layer. Thus, the initial contact state by the cleaning member can be maintained for a long time, and the wear amount and damage of the image carrier that is the member to be cleaned can be reduced. For this reason, the cleaning performance by the cleaning member can be improved and the maintainability of the member to be cleaned can be reliably ensured.
Furthermore, since it is not necessary to provide a mechanism for changing the installation angle with the wear of the cleaning member, it is possible to improve the cleaning performance and ensure the maintainability of the member to be cleaned at low cost without considering the wear of the cleaning member. Can be realized.
In particular, according to the present invention, since the cleaning member moving mechanism is provided, the contact position of the cleaning member with respect to the member to be cleaned can be made variable. Therefore, the member to be cleaned generated by the defective portion (small protrusion) of the cleaning member. The occurrence of local flaws on the surface can be suppressed, and the cleaning performance can be maintained with high accuracy.
Further, according to the image forming apparatus provided with such a cleaning apparatus, it is possible to easily construct an image forming apparatus that has good cleaning performance and good maintainability of the image carrier that is a member to be cleaned. .

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 3 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
In FIG. 1, the image forming apparatus includes a photosensitive drum 10 and an intermediate transfer belt 20 disposed to face the photosensitive drum 10 in order to transfer a toner image from the photosensitive drum 10.
In the present embodiment, the photosensitive drum 10 includes a photosensitive layer whose resistance value is reduced by light irradiation. Around the photosensitive drum 10, a charging device 11 for charging the photosensitive drum 10 and An exposure device 12 for writing an electrostatic latent image of each color component (in this example, yellow (Y), magenta (M), cyan (C), black (K)) on the charged photosensitive drum 10, and a photosensitive member. A rotary developing device 13 that visualizes each color component latent image formed on the drum 10 with each color component toner, the intermediate transfer belt 20, and a drum cleaner that cleans residual toner on the photosensitive drum 10 ( And a cleaning device 17.

Here, as the charging device 11, for example, a charging roll is used, but a charging device such as a corotron may be used.
The exposure device 12 may be any device that can write an image on the photosensitive drum 10 with light. In this example, for example, a print head using LEDs is used, but the present invention is not limited to this, and EL is used. For example, a scanner that scans a laser beam with a polygon mirror may be selected as appropriate.
Further, the rotary type developing device 13 is rotatably mounted with developing devices 13a to 13d containing respective color component toners. For example, the respective color component toners are attached to a portion of the photosensitive drum 10 where the potential is lowered by exposure. The toner to be used is not particularly limited in shape and particle size, and any toner may be used as long as it is accurately placed on the electrostatic latent image on the photosensitive drum 10.
However, from the viewpoint of ensuring high resolution, in the present embodiment, a small-diameter toner having an average particle diameter of 3 to 9 μm is preferable, and from the viewpoint of ensuring the granularity and high transferability of the toner image, the shape factor It is preferable to use a spherical toner (for example, polymerized toner) having a particle size of 140 or less, preferably 130 or less.
The shape factor is given by
Shape factor =
{(Absolute maximum length of toner diameter) ² / (projected area of toner)} × (π / 4) × 100
In this example, the rotary developing device 13 is used, but four developing devices may be used.
Furthermore, the drum cleaner 17 may be appropriately selected, such as one that employs a blade cleaning method, as long as the toner remaining on the photosensitive drum 10 is cleaned. However, there may be an embodiment in which the drum cleaner 17 is not used when toner having a high transfer rate is used.

Further, in the present embodiment, the intermediate transfer belt 20 is stretched around a plurality of stretching rolls 21 to 23 and is rotated in a predetermined direction using, for example, the stretching roll 23 as a driving roll. As the intermediate transfer belt 20 used here, for example, a predetermined thickness is prepared by dispersing a predetermined amount of a resistance adjusting agent such as carbon in a resin such as polyimide resin or polyamide resin.
A primary transfer roll 25 as a primary transfer device is disposed in contact with a part of the contact area where the intermediate transfer belt 20 is in close contact with the photosensitive drum 10 from the back side of the intermediate transfer belt 20, and a predetermined primary transfer bias is applied. Applied.
Furthermore, a secondary transfer roll 30 as a secondary transfer device is disposed opposite to the tension roll 22 of the intermediate transfer belt 20 with the tension roll 22 as a backup roll, for example, the secondary transfer roll 30. A predetermined secondary transfer bias is applied to the tension roller 22 and the tension roll 22 that also serves as a backup roll is grounded.

  A recording material 40 such as paper is accommodated in a supply tray 41, supplied by a pickup roll 42, guided to a secondary transfer portion through a registration roll 43, and then to a fixing device 45 through a conveyance belt 44. It is conveyed and discharged to a discharge tray 48 through a transfer roll 46 and a discharge roll 47.

Furthermore, a belt cleaner (cleaning device) 26 is disposed at a portion of the intermediate transfer belt 20 facing the stretching roll 21.
In the present embodiment, as shown in FIG. 4A, the belt cleaner 26 has a cleaner case 51 that opens to face the toner image carrying surface of the intermediate transfer belt 20, and the cleaner case 51 has an opening. A metal scraper 52 is disposed as a cleaning member. In the figure, reference numeral 53 denotes a film seal that is provided at the lower edge of the opening of the cleaner case 51 and elastically contacts the intermediate transfer belt 20.
In the present embodiment, the metal scraper 52 has a leading end that faces the direction of movement of the intermediate transfer belt 20 and has an acute angle θ (for example, 12 ° to 20 °) with respect to the intermediate transfer belt 20. The leading edge portion is brought into contact with the surface of the intermediate transfer belt 20.

In particular, in the present embodiment, the metal scraper 52 contacts the base substrate 61 such as SUS and the intermediate transfer belt 20 in the base substrate 61 as shown in FIGS. 4 (a) and 4 (b). And a covering layer 62 covering a substantially half region including a portion corresponding to the portion.
As the coating layer 62 of this example, a surface layer 63 made of a diamond-like carbon film (DLC film) and an intermediate layer (3 in this example) for bonding the surface layer 63 and the base substrate 61 together. 64 to 66 is interposed between the layers).
Here, as the intermediate layers 64 to 66, for example, a first intermediate layer 64 made of a mixed film of tungsten carbon (WC) and DLC, for example, in order from the surface layer 63 side, a mixture of chromium (Cr) and WC. A second intermediate layer 65 made of a film and a third intermediate layer 66 made of chromium are disposed. For example, the surface layer 63 and the first intermediate layer 64 are firmly bonded based on a common DLC film structure. In addition, the base substrate 61 and the third intermediate layer 66 as the base layer are firmly bonded with each other (SUS and chromium), and the first intermediate layer 64 and the third intermediate layer 66 are used as the intermediate adhesive layer. It is firmly bonded via the functioning second intermediate layer 65 (the first intermediate layer 64 and WC have a common structure, and the third intermediate layer 66 and Cr have a common structure).

The coating layer 62 is manufactured by a microwave plasma CVD method, a direct current plasma CVD method, a high frequency plasma CVD method, a magnetic field plasma CVD method, an ion beam sputtering method, an ion beam deposition method, a reactive plasma sputtering method, It is formed by an unbalanced magnetron sputtering method or the like. The raw material gas that can be used at this time is a carbon-containing gas, for example, a hydrocarbon gas such as methane, ethane, propane, ethylene, benzene, or acetylene, or a halogenated gas such as methylene chloride, carbon tetrachloride, chloroform, or trichloroethane. Carbons, alcohols such as methyl alcohol and ethyl alcohol, ketones such as acetone and diphenyl ketone, gases such as carbon monoxide and carbon dioxide, and these gases include N ₂ , H ₂ , O ₂ , H ₂ O, What mixed Ar etc. is mentioned.

Further, the physical properties of the coating layer 62 manufactured in this way include a. Vickers hardness is 1500 Hv or more, b. The friction coefficient is smaller than the friction coefficient of the base substrate 61 before coating; c. It is necessary to satisfy that the surface roughness is equal to or less than the surface roughness of the base substrate 61 before coating.
In the present embodiment, the characteristics of the coating layer 62 mainly reflect the characteristics of the surface layer 63 made of the DLC film, the hardness of the coating layer 62 is set in the range of 1500 Hv to 9100 Hv, and the friction coefficient of the coating layer 62 Is 0.1 to 0.3 in terms of load on the running of the intermediate transfer belt 20, wear of the intermediate transfer belt 20, and wear of the coating layer 62 of the metal scraper 52. In the case of the base substrate 61 made of SUS, It is set to be smaller than 0.6 to 1.0.
When the film forming method is used, the coating layer 62 is formed on the surface of the base substrate 61 at the molecular level, so that the required high-precision surface roughness (high quality edge shape) is obtained. In particular, when the base substrate 61 is manufactured, the tip shape of the base substrate 61 may be formed, and the conventionally used etching technique can be used as it is.
Furthermore, the layer thicknesses of the layers 63 to 66 constituting the coating layer 62 may be appropriately selected, but it is desirable to make the intermediate layers 64 to 66 as thin as possible in order to shorten the film forming time. In addition, it is desirable to make the outermost layer (surface layer) 63 thicker in order to increase the strength of the coating layer 62, but the coating layer 62 may become very fragile when the layer thickness is 2 μm or more. It is necessary to keep in mind.

In particular, in the present embodiment, the metal scraper 52 is supported via a moving mechanism 70 as shown in FIGS. 5A and 5B, and can be freely moved along a direction orthogonal to the intermediate transfer belt 20. It is a mode that can be moved to.
The moving mechanism 70 includes a pair of guide shafts 73 laid along one side surface of the metal scraper 52 between a pair of fixed mounting members 74 such as a pair of frames positioned near both ends of the metal scraper 52. A support piece 72 is formed so as to protrude near both ends of one side surface 52, and an engagement hole 75 in which each guide shaft 73 is loosely fitted is provided in the support piece 72, and each guide shaft 73 is provided in the engagement hole 75. By making it penetrate, the metal scraper 52 is slidably moved along the guide shaft 73.

Next, the operation of the image forming apparatus according to the present embodiment will be described.
When the image forming apparatus starts an image forming operation, each color component toner image on the photosensitive drum 10 is sequentially formed and is primarily transferred onto the intermediate transfer belt 20 sequentially by the transfer electric field of the primary transfer roll 25.
Thereafter, the toner image primarily transferred to the intermediate transfer belt 20 is secondarily transferred to the recording material 40 by the transfer electric field of the secondary transfer roll 30, and is carried to the fixing step.

In such an image forming process, the residual toner T on the intermediate transfer belt 20 is cleaned by the belt cleaner 26.
At this time, the metal scraper 52 is appropriately moved by the moving mechanism 70 along the direction orthogonal to the intermediate transfer belt 20 to remove the residual toner T on the intermediate transfer belt 20 while changing the contact position with the intermediate transfer belt 20. Scrape.
Here, assuming that the contact position of the metal scraper 52 to the intermediate transfer belt 20 is fixed without providing the moving mechanism 70, the defect portion of the scraper base material provided with the high hardness coating layer 62 is assumed. If there is a (minute projection), it may contact with the same position of the intermediate transfer belt 20 for a long period of time, which may cause local scratches on the surface of the intermediate transfer belt 20. However, in the aspect provided with the moving mechanism 70 as in the present embodiment, when the metal scraper 52 is movable along the direction orthogonal to the intermediate transfer belt 20, the contact position is made variable. Such a situation can be effectively avoided.
Therefore, in the present embodiment, even if the belt cleaner 26 is used for a long time, the metal scraper 52 is hardly worn, and the intermediate transfer belt 20 is damaged. Also not seen.
In the present embodiment, the belt scraper 26 using the metal scraper 52 is shown. However, for the drum cleaner 17, the same metal scraper 52 as the belt cleaner 26 may be used. The belt cleaner 26 and the drum cleaner 17 can also serve as a metal scraper 52 as a cleaning member.

Embodiment 2
6A to 6C show a moving mechanism 70 of the belt cleaner 26 used in the second embodiment of the image forming apparatus to which the present invention is applied. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the present embodiment, the drive mechanism 80 is configured to forcibly move the scraper 52 along a direction orthogonal to the intermediate transfer belt 20.
That is, the moving mechanism 70 includes support elements (support piece 72, guide shaft 73, engagement hole 75) for free movement similar to the first embodiment, and the metal scraper 52 is forcibly moved. A drive mechanism 80 is provided.
In this example, the drive mechanism 80 has an operation rod 81 fixedly disposed on the back surface of the metal scraper 52 along the longitudinal direction thereof, and both ends of the operation rod 81 from both ends of the metal scraper 52 in the longitudinal direction. An eccentric cam 82 that is driven and connected to a stepping motor (not shown) is disposed on one end side of the operating rod 81, while the other end side of the operating rod 81 is biased toward the eccentric cam 82 side. The urging spring 83 is disposed and the stepping motor is controlled to rotate the eccentric cam 82, and the actuating rod 81 contacting the eccentric cam 82 is opposed to or urged against the urging force of the urging spring 83. It is designed to advance and retreat based on power.
Further, in the present embodiment, the operation control of the eccentric cam 82 employs a method in which a stepping motor is directly attached and rotated by one step for each job of the printer. A method in which a DC motor is attached and rotated for each job may be used.

Next, the operation of the belt cleaner 26 according to the present embodiment will be described.
In the present embodiment, the metal scraper 52 is forcibly moved along the direction orthogonal to the intermediate transfer belt 20 by the moving mechanism 70, and the intermediate transfer belt 20 is made variable while changing the position of contact with the intermediate transfer belt 20. The residual toner on the belt 20 is scraped off.
That is, in this cleaning process, when the eccentric cam 82 rotates by operating the stepping motor for each job of the printer, the operating rod 81 (metal scraper 52) moves forward and backward as the eccentric cam 82 rotates (see FIG. 6 (a) and (b)).
At this time, the metal scraper 52 that is in contact with the intermediate transfer belt 20 is forcibly moved along the direction orthogonal to the intermediate transfer belt 20 as the operating rod 81 moves forward and backward, and residual toner on the intermediate transfer belt 20. T is scraped off.
According to the present embodiment, it is possible to effectively prevent local scratches on the surface of the intermediate transfer belt 20 that occur when the contact position of the metal scraper 52 with respect to the intermediate transfer belt 20 is fixed.
Therefore, even if the belt cleaner 26 is used for a long period of time, the metal scraper 52 is hardly worn, and the intermediate transfer belt 20 is not damaged.

Embodiment 3
FIG. 7A shows a main part of the second embodiment of the cleaning device to which the present invention is applied.
In the figure, a cleaning device 26 is made of a metal scraper 90 (including a “base substrate 61 + coating layer 62” similar to that of the first embodiment and having a moving mechanism 70) on the upstream side in the moving direction of the intermediate transfer belt 20. And a cleaning member (for example, a cleaning roll) 93 for electrostatic attraction is provided on the downstream side thereof.
In this example, the metal scraper 90 has a leading end in a direction opposite to the moving direction of the intermediate transfer belt 20 and is inclined with respect to the intermediate transfer belt 20 by a predetermined angle. Can move freely. The metal scraper 90 is connected to a charging bias power supply 91 to which a charging bias having the same polarity as the residual toner T can be applied. An opposed roll 92 is disposed.
On the other hand, the cleaning roller 93 is connected to an attracting bias power source 94 to which an attracting bias having a polarity opposite to that of the residual toner T can be applied. A roll 95 is provided.

According to the present embodiment, the metal scraper 90 of the cleaning device 26 scrapes part of the residual toner T, thins the residual toner T, and charges the residual toner T that has not been scraped off with a charging bias. The charged residual toner T is positively charged with a negative polarity, and is electrostatically adsorbed and collected by a cleaning roll 93 located on the downstream side.
At this time, the metal scraper 90 covered with the special coating layer 62 and provided with the moving mechanism 70 is hardly worn even when used for a long period of time, and the intermediate transfer belt 20 is also damaged by the metal scraper 90. Nothing is seen.

  Note that the present embodiment is not limited to the mode shown in FIG. 7A. For example, as shown in FIG. 7B, the metallic transfer is made in the direction along the moving direction of the intermediate transfer belt 20. The scraper 90 may be disposed in an inclined manner, or as shown in FIG. 7C, no charging bias is applied to the metal scraper 90 and the metal scraper 90 and the cleaning roll 93 are not applied. A charging roll 96 as a charging member is provided, a charging bias power source 97 is connected to the charging roll 96, and a grounding opposing roll 98 is provided at a portion facing the charging roll 96 with the intermediate transfer belt 20 interposed therebetween. You may make it do.

Embodiment 4
FIG. 8A shows an image forming apparatus according to a fourth embodiment to which the present invention is applied.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment. However, unlike the first embodiment, the image forming apparatus includes an intermediate transfer belt 20 having elasticity, and a photosensitive drum 10 in a certain region. The intermediate transfer belt 20 is placed in contact with the shape. Components similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted here.

In the present embodiment, as shown in FIG. 8B, the intermediate transfer belt 20 includes a belt base material 101 made of an elastic material, and a coating layer 102 that covers the surface of the belt base material 101. .
Examples of the belt substrate 101 used in the present embodiment include vulcanized rubber and thermoplastic elastomer. Here, as raw material rubber materials, general diene rubbers such as styrene / butadiene rubber (SBR), polyisoprene rubber (IIR), ethylene / propylene / diene rubber (EPDM), polybutadiene rubber (BR), acrylic rubber ( ACM, ANM), etc., but acrylonitrile butadiene rubber is relatively high in rigidity, has a volume resistivity close to semiconductivity, and has good fluidity in the mold. (NBR), hydrogenated NBR, chloroprene rubber (CR), epichlorohydrin rubber (CO, ECO), polyurethane rubber (PUR) and the like are preferable.
On the other hand, polyester-based, polyurethane-based, styrene-butadiene triblock-based, polyolefin-based, etc. are used as the thermoplastic elastomer. When such a thermoplastic elastomer is used, recycling is possible, which is environmentally preferable.
Furthermore, the material of the belt base material 101 is not necessarily one type, and two or more types of materials can be blended. For example, a material obtained by blending chloroprene rubber (CR) and EPDM is used.
In addition, a conductive filler or an insulating filler can be added to the belt base material 101 to adjust the volume resistivity of the belt base material 101.
The coating layer 102 is made of a polyurethane resin, a polyester resin, a polyacrylic resin, or the like as a binder, and a predetermined filler, typically a lubricous filler and a conductive filler are dispersed. The surface roughness Rz (δ) of the coating layer 102 is preferably set to 1.5 to 9 μm or less in consideration of the adhesion to the photosensitive drum 10 and the toner particle size to be used.

Further, as shown in FIG. 8A, the intermediate transfer belt 20 is stretched between four stretching rolls 21 to 24 and is positioned between the rotary developing device 13 and the drum cleaner 17. A predetermined contact area is closely arranged along the surface of the photosensitive drum 10.
Here, the intermediate transfer belt 20 and the photosensitive drum 10 may be driven by separate drive systems, but in the present embodiment, the intermediate transfer belt 20 is an elastic belt, and in addition, the photosensitive drum 10. Therefore, the intermediate transfer belt 20 is driven to rotate by using the photosensitive drum 10 as a drive source, for example.
In the present embodiment, the belt cleaner 26 is disposed at a portion corresponding to the tension roll 24 of the intermediate transfer belt 20, and as shown in FIG. 8B, the same metal as in the first embodiment is used. A scraper 52 made of “(base substrate 61 + covering layer 62” and moving mechanism 70) is provided.

According to the present embodiment, the metal scraper 52 of the belt cleaner 26 is disposed in contact with the intermediate transfer belt 20 made of an elastic belt. However, the metal scraper 52 has a smooth coating layer 62 with high hardness and low friction. Therefore, the amount of wear of the metal scraper 52 itself is small, and the intermediate transfer belt 20 is less likely to be damaged.
Further, since the metal scraper 52 is provided along the direction orthogonal to the intermediate transfer belt 20 because the moving mechanism 70 is provided, the intermediate transfer belt may be generated when the contact position of the metal scraper 52 is fixed. The occurrence of local flaws on the surface 20 can be suppressed, and the maintainability of the intermediate transfer belt 20 can be maintained better.
Therefore, the intermediate transfer belt 20 made of an elastic belt and the metal scraper 52 can be combined, and the cleaning performance of the metal scraper 52 can be kept good while maintaining the maintainability of the intermediate transfer belt 20. .

Furthermore, in this embodiment, since the intermediate transfer belt 20 is driven and rotated by driving the photosensitive drum 10, the drive control cost of the intermediate transfer belt 20 can be greatly reduced.
Furthermore, since the contact width of the intermediate transfer belt 20 to the photosensitive drum 10 in the primary transfer is set to be very wide, for example, 50 mm or more, stable follow-up to the intermediate transfer belt 20 can be realized, and the transfer nip can be realized. Since there is no useless gap before and after the area, primary transfer is performed in a state where there is no scattering of toner due to discharge.
In particular, in the present embodiment, since a wide transfer nip area between the photosensitive drum 10 and the intermediate transfer belt 20 is ensured, it is possible to reduce the pressure in the transfer nip area. The situation where the body drum 10 and the intermediate transfer belt 20 are completely in close contact with each other is more reliably avoided.

Using the belt cleaner 26 (cleaning device) according to the second embodiment, the idling operation was continuously performed, and the state of change in wear of the metal scraper 52 was examined. In this embodiment, the moving mechanism 70 remains fixed, and the idling operation is performed with the contact position of the metal scraper 52 against the belt fixed at the same position.
Here, the metal scraper 52 used in the embodiment is configured as follows.
Base substrate 61: SUS plate (thickness: 100 μm)
Coating layer 62:
Surface layer 63: DLC film 1.0 μm
First intermediate layer 64: DLC + WC film 1.0 μm
Second intermediate layer 65: Cr + WC film 0.5 μm
Third intermediate layer 66: Cr film 0.2 μm
Mounting angle θ of metal scraper 52: 20 °
Elastic deformation amount of the metal scraper 52 (amount of biting into the belt): 1.2 mm
In addition, as a comparative example, it was set as the aspect using the metal scraper without the coating layer 62 of an Example.

When the belt cleaner 26 was idled under the same conditions in both the example and the comparative example, as shown in FIG. 9, in contrast to the idling operation performed continuously for 15 hours, the example was made of metal. The wear amount of the scraper 52 was hardly seen, and was about 3 μm, but it was confirmed that the wear amount of the metal scraper 52 reached 25 μm in the comparative example.
Thereby, it was confirmed that the example was excellent in terms of wear of the metal scraper 52.
A similar friction test was performed with the moving mechanism 70 (the model of the second embodiment) stopped using a part of the metal scraper 52 having a defect portion. Local damage was seen. On the other hand, when the same test was performed by operating the moving mechanism 70, such damage was not seen.
As described above, by operating the moving mechanism 70, the contact position of the metal scraper 52 with respect to the belt can be made variable, so that local damage to the belt surface can be prevented, and the belt maintainability can be improved. It was confirmed that

(A) is explanatory drawing which shows the outline | summary of the cleaning apparatus which concerns on this invention, and the cleaning member used for this, (b) is explanatory drawing which shows the outline | summary from B direction in (a). 1 is an explanatory diagram showing an outline of an image forming apparatus according to the present invention. 1 is an explanatory diagram showing an overall configuration of Embodiment 1 of an image forming apparatus to which the present invention is applied. (A) is explanatory drawing which describes the principal part of the cleaning apparatus (belt cleaner) which concerns on Embodiment 1, (b) is explanatory drawing which shows the detail of the coating layer of B part in (a). (A) is explanatory drawing which shows the moving mechanism which concerns on Embodiment 1, (b) is explanatory drawing which shows the BB cross section in (a). (A) (b) is explanatory drawing which shows the moving mechanism which concerns on Embodiment 2, (c) is explanatory drawing which shows CC cross section in (a). (A) is explanatory drawing which shows the outline | summary of the cleaning apparatus which concerns on Embodiment 3, (b) (c) is explanatory drawing which shows the deformation | transformation form of the cleaning apparatus which concerns on Embodiment 3. FIG. (A) is explanatory drawing which shows the whole structure of the image forming apparatus which concerns on Embodiment 4, (b) is explanatory drawing which shows the cross-sectional structure of an intermediate transfer belt. It is explanatory drawing which shows the performance experiment about the tip wear amount of the scraper which concerns on an Example and a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image carrier, 1a ... Image forming carrier, 1b ... Image carrier, 2 ... Image forming particle, 3 (3a, 3b) ... Cleaning device, 4 (4a, 4b) ... Cleaning member, 5 ... Base group 6 ... coating layer, 6a ... surface layer, 6b ... intermediate layer, 7 ... moving mechanism, 8a ... primary transfer means, 8b ... secondary transfer means, 9 ... recording material

Claims (8)

In a cleaning device for cleaning image forming particles remaining on an image carrier,
A cleaning member that is in contact with the image carrier and whose contact portion shape with the image carrier is maintained in an undeformed state regardless of the movement of the image carrier, and a direction crossing the moving direction of the image carrier. A moving mechanism that allows the cleaning member to move freely,
The cleaning member includes a plate-like base substrate, and a covering layer that covers at least a portion of the base substrate corresponding to a contact portion with the image carrier,
a. Vickers hardness is 1500 Hv or more,
b. The surface friction coefficient is smaller than the friction coefficient of the base substrate before coating,
c. The surface roughness is below the surface roughness of the base substrate before coating,
A cleaning device characterized by satisfying the above. The cleaning device according to claim 1.
A cleaning device characterized in that the moving mechanism allows the cleaning member to freely move along a direction crossing the moving direction of the image carrier. The cleaning device according to claim 1.
A cleaning device characterized in that the moving mechanism allows the cleaning member to be forcibly moved along a direction crossing the moving direction of the image carrier. The cleaning device according to claim 1.
The covering layer of the cleaning member includes a diamond-like carbon film (DLC film), a cubic boron nitride film (C-BN film), a silicon carbide film (SiC film), a chromium nitride film (CrN film), and a tungsten carbon film (WC). Film) and ta-C film (Tetrahedral Amorphous Carbon film). The cleaning device according to claim 1.
An image forming particle is a toner having a shape factor of 140 or less. The cleaning device according to claim 1.
The image forming particle is a toner having a volume average particle diameter of 3 to 9 μm. An image carrier on which a visible image by image-forming particles is conveyed;
An image forming apparatus comprising: the cleaning device according to claim 1 for cleaning image forming particles remaining on the image carrier. The aspect of the image forming apparatus according to claim 7, wherein the image carrier includes an image forming carrier that forms and carries a visible image, and an image carrier that is disposed to face the image forming carrier.
An image forming apparatus comprising: a cleaning device disposed on each of the image forming carrier and the image transporting carrier; and each cleaning device having a cleaning member having the same configuration.

Images