JP5233464B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a composite machine thereof. The surface of an image holding member charged by a charging device is subjected to exposure according to image information by a latent image forming apparatus. After forming the electrostatic latent image, toner is supplied from the developing device to the electrostatic latent image portion to form a toner image on the surface of the image holding member, and the toner image thus formed is transferred from the image holding member to the transfer medium. In the image forming apparatus in which the toner remaining on the surface of the image holding member is removed by pressing the cleaning member against the surface of the image holding member after the transfer to the surface of the image holding member, an appropriate lubricant is applied to the surface of the image holding member. The image forming apparatus is characterized in that good image formation can be stably performed.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these, an electrostatic latent image is formed by exposing the surface of an image holding member charged by a charging device according to image information by a latent image forming apparatus. After forming, toner is supplied from the developing device to the electrostatic latent image portion to form a toner image on the surface of the image holding member, and the toner image thus formed is transferred from the image holding member to the transfer medium. Thereafter, a cleaning member such as a cleaning blade is pressed against the surface of the image holding member to remove toner remaining on the surface of the image holding member.

  Here, when the cleaning member is pressed against the surface of the image holding member after the toner image is transferred as described above and the toner remaining on the surface of the image holding member is continuously removed, the cleaning is performed. There are problems that the member is worn and the cleaning performance is deteriorated, and that the surface of the image holding member is worn and the life of the image holding member is shortened. In particular, in recent years, in order to form a high-quality image, a toner having a small particle size or a spherical shape has been used, and when such a toner is used, the toner easily slips through the cleaning member, There has been a problem in that defective cleaning occurs and streak noise occurs in the formed image.

  For this reason, conventionally, when the lubricant is externally added to the toner in the developing device and the toner is supplied from the developing device to form a toner image on the surface of the image holding member, the lubricant externally added in this way is used. Is supplied to the surface of the image holding member, and the lubricant thus supplied is applied to the surface of the image holding member by the cleaning member, so that the frictional resistance on the surface of the image holding member is reduced, and the cleaning member In addition, the image holding member is prevented from being worn, and the cleaning performance of the cleaning member is improved to prevent the generation of streak noise in the formed image.

  However, when the lubricant is externally added to the toner as described above, generally, the lubricant is charged to a polarity opposite to that of the toner by contact with the toner, and the toner is supplied from the developing device as described above to supply the image holding member. When the toner image is formed on the surface of the toner, the externally added lubricant is supplied to the non-image portion where the toner is not supplied. When a specific image is continuously formed, the non-image of the image holding member is formed. There is a problem that the lubricant is supplied only to the portion, and the lubricant is hardly supplied to the image portion, and the frictional resistance in the image portion is increased.

  Conventionally, as shown in Patent Documents 1 and 2, etc., the lubricant is supplied from the lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer medium, and thus supplied. The first lubricant is externally added to the toner in the developing device as shown in Patent Documents 3, 4 and the like, in which the applied lubricant is applied to the surface of the image holding member by the cleaning member. The second lubricant is supplied from the lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer medium, and the lubricant thus supplied to the surface of the image holding member is used as the cleaning member. Has been proposed to be applied to the surface of the image holding member.

  Here, in supplying the lubricant from the lubricant supply means to the surface of the image holding member after the toner image is transferred to the transfer medium as described above, in the above-described Patent Documents 1 to 4, After the lubricant is scraped off from the solid lubricant by the brush roller, the brush roller is brought into contact with the surface of the image holding member after the toner image is transferred, and the scraped lubricant is applied to the surface of the image holding member. The cleaning member is pressed against the surface of the image holding member, and the lubricant supplied to the surface of the image holding member is applied to the surface of the image holding member.

However, when the toner remaining on the surface of the image holding member is removed by the cleaning member as described above, the brush roller is brought into contact with the surface of the image holding member to apply the lubricant. As a result, the toner remaining on the surface of the image holding member gradually adheres and accumulates. There was a problem that it could not be applied properly.
JP 2003-57996 A JP 2006-259661 A JP 2003-149995 A JP 2003-316201 A

  In the present invention, an electrostatic latent image is formed on a surface of an image holding member charged by a charging device according to image information by a latent image forming device, and then a toner from a developing device is applied to the electrostatic latent image portion. To form a toner image on the surface of the image holding member. After the toner image thus formed is transferred from the image holding member to the transfer medium, a cleaning member is pressed against the surface of the image holding member. An object of the present invention is to solve the above-described various problems in an image forming apparatus in which toner remaining on the surface of an image holding member is removed.

  That is, according to the present invention, in the image forming apparatus as described above, the first lubricant is externally added to the toner in the developing device, and the brush roller is formed on the surface of the image holding member after the toner image is transferred to the transfer medium. When supplying the second lubricant from the second lubricant supply means using a rotation supply member such as a toner, the toner remaining on the surface of the image holding member adheres to the rotation supply member such as a brush roller and accumulates. It is an object of the present invention to prevent the occurrence of the problem and to stably supply the lubricant onto the surface of the image holding member so that good image formation can be stably performed.

In the present invention, in order to solve the above-described problems, an image holding member that holds and moves a toner image, a charging device that charges the surface of the image holding member, and a surface of the charged image holding member. A latent image forming apparatus that forms an electrostatic latent image by performing exposure according to image information, and a developer containing toner and a first lubricant are guided to an image holding member on which the electrostatic latent image is formed by a developing roller. A developing device for forming a toner image on the surface of the image holding member and supplying the first lubricant, a transfer device for transferring the toner image formed on the image holding member to a transfer medium, and rotation from the solid lubricant. Second lubricant supply means for supplying the second lubricant scraped off by the supply member to the surface of the image holding member after the toner image is transferred, and remaining on the surface of the image holding member after the toner image is transferred Member for removing toner An image forming apparatus comprising a charging polarity of the first lubricant is supplied to the surface of the image holding member from the developing roller, the second lubricant is supplied to the surface of the image holding member from rotating feed member above and a charging polarity of the toner is set to be the opposite polarity, together with applying a bias voltage to supply a second lubricant from a bias power source of the above rotary feed member above the surface of the image holding member, the bias voltage The potential was set between the potential of the electrostatic latent image portion where the potential was lowered by exposure by the latent image forming apparatus and the potential of the developing bias voltage applied to the developing roller from the developing bias power source .

  Here, in the above image forming apparatus, the toner and the image holding member have the same charging polarity, and a developing bias voltage is applied to the developing roller from a developing bias power source so that the toner is transferred to the latent image. It can be supplied to the portion of the electrostatic latent image whose potential has been lowered by exposure by the forming apparatus.

In the image forming apparatus described above, first lubricant is supplied to the surface of the image holding member with a toner as described above is charged by contact with the toner, the toner and the opposite polarity as the It becomes like this.

In the image forming apparatus described above, per the supplies to the surface of the image holding member after the second lubricant scraped by the rotating supply member from the solid lubricant toner image has been transferred, the second lubricating agents for is to so that is properly supplied to the surface of the image holding member from rotating feed member, a bias voltage from a bias power source to the rotary feed member second lubricant direction supplied to the surface of the image holding member, that is, so as to apply a charge having the same polarity of the bias voltage of the second lubricant or toner.

In the image forming apparatus described above, hits the applying a bias voltage to be supplied to the surface of the second lubricant image holding member to the rotating feed member above from the bias power supply, the potential of the bias voltage to applied , and between a potential of the developing bias voltage applied to the developing roller from the potential and the developing bias power supply of an electrostatic latent image portion potential by exposure to latent image forming apparatus as described above is lowered.

  Further, in the above image forming apparatus, if the first lubricant and the second lubricant have a triboelectric charge series between the triboelectric charge series of the toner and the rotation supply member, Even when the same zinc stearate is used for the first lubricant and the second lubricant, the charge polarity of the first lubricant and the second lubricant can be reversed as described above. For example, in the case where the same zinc stearate is used for the first lubricant and the second lubricant, a negatively chargeable toner having a triboelectric charging series such as polystyrene on the negative side of zinc stearate is used, and nylon is used. When the rotation supply member whose frictional charging series is on the plus side of zinc stearate is used, the first lubricant is positively charged by contact with the toner, while the second lubricant is in contact with the rotation supply member. Therefore, even when the same zinc stearate is used, the first lubricant and the second lubricant are charged with opposite polarities.

  In the image forming apparatus, the cleaning member is provided at a position downstream of the second lubricant supply unit in the moving direction of the image holding member, and the image is held by the cleaning member after being transferred. The toner remaining on the surface of the member is removed, and the first lubricant and the second lubricant supplied to the surface of the image holding member can be applied to the surface of the image holding member.

  In the image forming apparatus of the present invention, the first lubricant supplied from the developing roller to the surface of the image holding member and the second lubricant supplied from the rotation supply member to the surface of the image holding member as described above. Since the charging polarity is reversed, the second lubricant is supplied from the rotation supply member to the surface of the image holding member to which the first lubricant is not supplied from the developing roller. The lubricant is appropriately supplied to the entire surface of the holding member, and the supplied lubricant is appropriately applied to the entire surface of the image holding member by the cleaning member.

  As a result, in the image forming apparatus of the present invention, the frictional resistance on the surface of the image holding member is appropriately reduced by the lubricant appropriately applied to the entire surface of the image holding member as described above, and the cleaning member and the image holding The wear of the member is suppressed, the cleaning performance of the cleaning member is improved, and streak noise is prevented from being generated in the formed image, and good image formation can be performed stably.

In the image forming apparatus of the present invention , the bias voltage in the direction in which the second lubricant is supplied to the surface of the image holding member from the bias power source to the rotation supply member, that is, opposite to the first lubricant due to so as to apply a charge having the same polarity of the bias voltage of the second lubricant or toner that is charged to a polarity, the second lubricant suitable for the surface of the image holding member in which the first lubricant is not supplied And the toner remaining on the surface of the image holding member after transfer is prevented from adhering to the rotation supply member, and the second lubricant is removed from the solid lubricant in the rotation supply member. The second lubricant is stably supplied to the surface of the image holding member by the rotation supply member for a long period of time without the scraping ability gradually decreasing, and good image formation can be stably performed for a longer period of time. Uninaru.

In particular, the potential of the bias voltage applied to the rotation supply member from the bias power source described above is the potential of the electrostatic latent image portion where the potential has been lowered by exposure by the latent image forming device, and the development bias voltage applied to the developing roller from the development bias power source. for it was set to between the potential, so that the second lubricant described above, are selectively supplied to the image portion of the image holding member in which the first lubricant after the toner image has been transferred is not supplied Thus, wasteful consumption of the second lubricant scraped from the solid lubricant is suppressed, and leakage between the rotation supply member and the image holding member is prevented. The

  Next, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  The image forming apparatus according to this embodiment includes negatively chargeable toners having different colors of yellow, magenta, cyan, and black, and a first lubricant having a frictional charge series on the plus side of each toner. Four developing devices 11 containing a developer are provided, and corresponding to each developing device 11, four drum-shaped photoconductors 10 are provided as image holding members. Here, when a polystyrene resin is used for the negatively chargeable toner, the first lubricant includes zinc stearate, magnesium stearate, stearin having a triboelectric charge series on the plus side of the polystyrene resin. Fatty acid metal salts such as lithium acid can be used.

  In this image forming apparatus, the respective photoconductors 10 described above are rotated, and the surface of each photoconductor 10 is charged to a predetermined negative potential by the charging device 12, and each photoconductor 10 thus charged is charged. The latent image forming device 13 performs exposure according to the image data, and forms an electrostatic latent image with a negative potential reduced on the surface of each photoconductor 10.

  Then, for each photoconductor 10 on which an electrostatic latent image is formed in this way, each color toner and the first lubricant are included by a developing roller 11a provided in each corresponding developing device 11. As shown in FIG. 2, a negative developing bias voltage is applied to each developing roller 11a from a developing bias power source 11b to be negatively charged while the developer is guided to a position facing each photoconductor 10. The toner is supplied to the portion of the electrostatic latent image where the negative potential is lowered, and reversal development is performed to form a toner image of each color on the surface of each photoconductor 10. In this case, the first lubricant positively charged by the contact with the toner is supplied mainly to the non-image portion of the photoreceptor 10 where the toner image is not formed.

  Next, the toner images of the respective colors formed on the respective photosensitive members 10 are respectively transferred to the intermediate transfer member 15 in the form of an endless belt that is driven around the roller 14 and is transferred into a roller shape. 16 is sequentially transferred in order to form a full-color toner image on the intermediate transfer member 15. When the toner image thus formed on the photoconductor 10 is transferred to the intermediate transfer body 15 by the primary transfer device 16, the negatively charged toner on the surface of the photoconductor 10 is attracted to the intermediate transfer body 15. In addition, a positively charged first lubricant supplied to the non-image portion of the photoreceptor 10 on which no toner image is formed is applied to the primary transfer device 16 so as to apply a positive voltage having a polarity opposite to that of the toner. The image remains on the non-image portion of the photoconductor 10 without being transferred to the intermediate transfer body 15.

  The full-color toner image thus formed on the intermediate transfer member 15 is guided to a position facing the secondary transfer device 17 formed into a roller shape by the intermediate transfer member 15, and the image forming apparatus includes: The sheet-like recording medium S accommodated in the lower part is guided between the intermediate transfer member 15 and the secondary transfer device 17 by the feed roller 18, and is formed on the intermediate transfer member 15 by the secondary transfer device 17. The full color toner image is secondarily transferred to the recording medium S.

  Thereafter, the recording medium S to which the full-color toner image is transferred is guided to the fixing device 19, and the transferred full-color toner image is fixed to the recording medium S, and then the recording in which the full-color toner image is fixed as described above. While the medium S is discharged, the toner remaining on the intermediate transfer body 15 without being transferred to the recording medium S is removed from the intermediate transfer body 15 by the second cleaning member 21 provided in the second cleaning device 20. .

  Further, in this image forming apparatus, the solid lubricant is applied to the surface of each photoreceptor 10 after the toner image is transferred to the intermediate transfer body 15 by the rotation supply member 31 in the second lubricant supply means 30 as described above. When scraping and supplying the second lubricant from 32, as shown in FIG. 2, a brush roller 31 that rotates in contact with the surface of the photoreceptor 10 is used as the rotation supply member 31, and the brush roller 31 is The solid lubricant 32 is pressed by a pressing member 33 made of a spring, and the brush roller 31 is rotated to scrape the second lubricant from the solid lubricant 32. In this embodiment, the brush roller 31 is used as the rotation supply member 31. However, instead of the brush roller 31, a foaming roller, a solid roller, or the like can be used.

  Here, for example, when a fatty acid metal salt such as zinc stearate, magnesium stearate, or lithium stearate is used as the second lubricant in the solid lubricant 32, the brush of the brush roller 31 is For example, a conductive brush made of a synthetic fiber such as nylon, rayon, or acrylic having a frictional charging series on the plus side of the second lubricant is used. If it does in this way, the 2nd lubricant scraped off by this brush roller 31 will come to be negatively charged by contact with brush roller 31.

  In this image forming apparatus, a negative bias voltage having the same polarity as the charging polarity of the second lubricant and toner is applied to the brush roller 31 from the bias power source 34.

  In this way, when a negative bias voltage having the same polarity as the charging polarity of the second lubricant and toner is applied to the brush roller 31, the second lubricant scraped off by the brush roller 31 and charged negatively is applied. Then, the toner is appropriately supplied to the image portion of the photoconductor 10 to which the first lubricant is not supplied, and the toner remaining on the surface of the photoconductor 10 after transfer adheres to the brush roller 31. Will be prevented. As a result, the ability to scrape the second lubricant from the solid lubricant 32 by the brush roller 31 is prevented from decreasing, and the second lubricant is stably supplied from the brush roller 31 to the surface of the photoconductor 10 over a long period of time. Become so.

  In particular, the potential of the bias voltage applied from the bias power source 34 to the brush roller 31 is applied to the electrostatic latent image portion whose potential has been reduced by exposure by the latent image forming device 13 and from the developing bias power source 11b to the developing roller 11a. If it is between the potential of the developing bias voltage to be generated, the second lubricant is selectively supplied to the image portion of the photoreceptor 10 where the first lubricant is not supplied. For this reason, the second lubricant scraped off from the solid lubricant 32 is suppressed from being wasted, and the potential difference between the brush roller 31 and the image portion of the photoconductor 10 is increased to cause leakage. Does not occur.

  For example, as shown in FIG. 3, the surface of the photoconductor 10 is charged to −600 V by the charging device 12, and the latent image forming device 13 exposes the photoconductor 10 thus charged according to the image data. When the surface of the photoreceptor 10 in the image area where the electrostatic latent image is formed becomes -100V, a developing bias voltage of -500V is applied to the developing roller 11a from the developing bias power source 11b. When reversal development is performed, the positively charged first lubricant x1 is supplied to the non-image portion of the photoconductor 10 where the electrostatic latent image is not formed.

  After the toner image formed on the surface of the photoconductor 10 is transferred to the intermediate transfer body 15, the bias power supply 34 applies the developing bias voltage to the brush roller 31 and the photoconductor 10 in the image portion. When a brush bias voltage of −300 V between the surface potential is applied, the second lubricant x2 scraped off by the brush roller 31 and charged negatively is not supplied with the first lubricant x1. 10 image portions are selectively supplied.

  As described above, when the bias power supply 34 applies a brush bias voltage of −300 V between the developing bias voltage and the surface potential of the photoconductor 10 in the image area to the brush roller 31, The positively charged first lubricant x1 supplied to the non-image portion is attracted to the brush roller 31. The first lubricant x1 transfers the toner image formed on the surface of the photoconductor 10 to the intermediate transfer. The first lubricant x1 is prevented from being collected by the brush roller 31 because it is strongly adhered to the surface of the photoconductor 10 by the pressure applied to the body 15.

  Then, after supplying the second lubricant to the surface of each photoconductor 10 by the second lubricant supply means 30 as described above, the cleaning member 40 is brought into pressure contact with the surface of each photoconductor 10, respectively. The toner remaining on the surface of the photoconductor 10 is removed, and the first lubricant and the second lubricant supplied to the surface of each photoconductor 10 are uniformly applied to the entire surface of each photoconductor 10.

  As a result, in the image forming apparatus of this embodiment, the toner remaining on the surface of the photoconductor 10 does not adhere to the brush roller 31 and gradually accumulate, and the lubricant is applied to the entire surface of the photoconductor 10. Is supplied stably, and the lubricant is uniformly applied to the entire surface of the photoconductor 10, so that good image formation can be stably performed over a long period of time.

1 is a schematic explanatory view showing an image forming apparatus according to an embodiment of the present invention. In the image forming apparatus according to the embodiment, the second lubricant is supplied to the surface of the photosensitive member after the toner image is transferred to the intermediate transfer member by the second lubricant supply unit, and then the cleaning member is applied to the surface of the photosensitive member. Is a partial schematic explanatory view showing a state in which the toner remaining on the surface of the photoconductor is removed by pressing and the first lubricant and the second lubricant supplied to the surface of the photoconductor are applied to the surface of the photoconductor It is. In the image forming apparatus of the embodiment, the potential of the bias voltage to be applied to the brush roller is divided into the potential of the electrostatic latent image portion whose potential has been reduced by exposure by the latent image forming apparatus, and the potential of the developing bias voltage to be applied to the developing roller. FIG. 6 is an explanatory diagram showing that the first lubricant is supplied to the non-image portion of the photoconductor and the second lubricant is supplied to the image portion of the photoconductor in the case where

Explanation of symbols

10 Photoconductor (image holding member)
DESCRIPTION OF SYMBOLS 11 Developing apparatus 11a Developing roller 11b Developing bias power supply 12 Charging apparatus 13 Latent image forming apparatus 14 Roller 15 Intermediate transfer body 16 Primary transfer apparatus 17 Secondary transfer apparatus 18 Feeding roller 19 Fixing apparatus 20 Second cleaning apparatus 21 Second cleaning member 30 Second lubricant supply means 31 Brush roller 32 Solid lubricant 33 Press member 34 Bias power supply 40 Cleaning member S Recording medium x1 First lubricant x2 Second lubricant

Claims (5)

An image holding member that holds and moves the toner image, a charging device that charges the surface of the image holding member, and the surface of the charged image holding member is exposed according to image information to form an electrostatic latent image A latent image forming apparatus, and a developer containing toner and a first lubricant is guided to an image holding member on which an electrostatic latent image is formed by a developing roller to form a toner image on the surface of the image holding member and The toner image is transferred to the developing device that supplies the first lubricant, the transfer device that transfers the toner image formed on the image holding member to the transfer medium, and the second lubricant that is scraped off from the solid lubricant by the rotation supply member. An image forming apparatus comprising: a second lubricant supply unit that supplies the surface of the image holding member after the toner image is removed; and a cleaning member that removes toner remaining on the surface of the image holding member after the toner image is transferred. From the above developing roller A charging polarity of the first lubricant is supplied to the surface of the holding member, Ri charging polarity is opposite the polarity der the second lubricant and the above toner supplied to the surface of the image holding member from rotating feed member of the A bias voltage for supplying the second lubricant to the surface of the image holding member from a bias power source is applied to the rotation supply member, and the potential of the bias voltage is lowered by exposure by the latent image forming apparatus. An image forming apparatus comprising: a potential between an electrostatic latent image portion and a developing bias voltage applied to a developing roller from a developing bias power source .   The image forming apparatus according to claim 1, wherein the toner and the surface of the image holding member have the same charging polarity, and a developing bias voltage is applied to the developing roller from a developing bias power source so that the toner is An image forming apparatus, characterized in that it is supplied to a portion of an electrostatic latent image whose potential has been lowered by exposure by the latent image forming apparatus. 3. The image forming apparatus according to claim 1 , wherein the triboelectric charging series of the first lubricant and the second lubricant are both between the triboelectric charging series of the toner and the rotating supply member. An image forming apparatus. 4. The image forming apparatus according to claim 1 , wherein the first lubricant and the second lubricant are made of zinc stearate. 5. 5. The image forming apparatus according to claim 1 , wherein the cleaning member is provided at a position downstream of the second lubricant supply unit in the moving direction of the image holding member, The cleaning member removes toner remaining on the surface of the image holding member after the transfer, and the first lubricant and the second lubricant supplied to the surface of the image holding member are applied to the surface of the image holding member. An image forming apparatus that is applied.

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