JP4141596B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a laser printer having a plurality of image forming units.
[0002]
[Prior art]
First, an electrophotographic image forming unit as shown in FIG. 4 in the color image forming apparatus will be described. The image forming unit 1B is an image forming unit that forms a black image on a drum-shaped photoconductor 10B that is an electrostatic latent image carrier, and the photoconductor 10B is rotationally driven by a drive mechanism (not shown). The surface of the photoconductor 10B is uniformly charged by a charging roller 11B as a charging unit, and then exposed to exposure light 12B from an exposure unit (not shown) including an optical writing device to form an electrostatic latent image. Then, the image is visualized with a black developer (a one-component developer composed of only black toner or a two-component developer composed of black toner and carrier) by a developing device 13B as a developing unit to form a black toner image.
[0003]
The black toner image on the photoconductor 10B is transferred by a transfer brush 15B as a transfer unit to a transfer sheet as a transfer body conveyed by a transfer belt 14 as will be described later in a transfer process. As a result, the black toner image is fixed and discharged. A cleaning blade 17B as a cleaning member in the cleaning device 16B cleans the photoconductor 10B after transfer to remove toner remaining on the surface of the photoconductor 10B from the photoconductor 10B, and the cleaning blade 17B removes the toner from the photoconductor 10B. The toner is transported to a waste toner container (not shown) by a waste toner transport screw 19B. Further, the cleaning device 16B is provided with a cleaning brush 18B as a cleaning auxiliary member for disturbing and removing toner on the surface of the photoconductor 10B on the upstream side of the cleaning blade 17B in the moving direction of the photoconductor 10B.
[0004]
FIG. 3 shows an example of a color image forming apparatus. In this color image forming apparatus, four image forming units 1B, 1C, 1M, and 1Y are arranged in parallel, and a transfer belt 14 that conveys transfer paper is provided. The image forming unit 1B that forms the black toner image is the same as the image forming unit 1B shown in FIG. 4, and the other image forming units 1C, 1M, and 1Y are substantially the same as the image forming unit 1B.
[0005]
That is, the image forming units 1C, 1M, and 1Y are image forming units that respectively form a cyan toner image, a magenta toner image, and a yellow toner image on the drum-shaped photoconductors 10C, 10M, and 10Y that are electrostatic latent image carriers. The photoconductors 10C, 10M, and 10Y are rotationally driven by a driving mechanism (not shown). The photoreceptors 10C, 10M, and 10Y are uniformly charged on their surfaces by charging rollers 11C, 11M, and 11Y as charging units, respectively, and then exposed to exposure light 12C from an exposure unit (including an optical writing device) (not shown). An electrostatic latent image is formed by exposure with 12M and 12Y, and a cyan developer (one-component developer composed only of cyan toner, or two composed of cyan toner and carrier) is developed by developing units 13C, 13M, and 13Y as developing means. Component developer), magenta developer (one-component developer consisting only of magenta toner, or two-component developer consisting of magenta toner and carrier), yellow developer (one-component developer consisting only of yellow toner, or yellow toner) And two-component developer consisting of a carrier and a carrier) The toner image, the yellow toner image.
[0006]
The transfer paper is fed from a paper feeding device (not shown), conveyed by the transfer belt 14, and after the black toner image on the photoconductor 10B is transferred by the transfer brush 15B as described above, the photoconductors 10C, 10M, and 10Y. The upper cyan toner image, magenta toner image, and yellow toner image are sequentially transferred in a similar manner by transfer brushes 15C, 15M, and 15Y as transfer means, thereby forming a full color image. The transfer paper on which the full color image is formed is discharged after the full color toner image is fixed by a fixing device (not shown).
[0007]
Cleaning blades 17C, 17M, and 17Y as cleaning members in the cleaning devices 16C, 16M, and 16Y respectively clean the photoconductors 10C, 10M, and 10Y after transfer, and remove the toner remaining on the surfaces of the photoconductors 10C, 10M, and 10Y. The toner removed from the photoconductors 10C, 10M, and 10Y by the cleaning blades 17C, 17M, and 17Y is transported to a waste toner storage unit (not shown) by the waste toner transport screws 19C, 19M, and 19Y. The
[0008]
Further, the cleaning devices 16C, 16M, and 16Y perform cleaning that disturbs and removes toner on the surfaces of the photoreceptors 10C, 10M, and 10Y on the upstream side in the moving direction of the photoreceptors 10C, 10M, and 10Y of the cleaning blades 17C, 17M, and 17Y. Cleaning brushes 18C, 18M, and 18Y as auxiliary members are provided. A color image forming apparatus in a form (so-called tandem system) that obtains a desired full-color image using black toner, cyan toner, magenta toner, and yellow toner is known.
[0009]
In addition, in an electrophotographic image forming apparatus, a technique for preventing the surface of a photoconductor from being worn by a cleaning belt by supplying a lubricant to the photoconductor and preventing the shortening of the life due to the wear of the photoconductor is known. Various lubricant supply systems have been proposed.
As a lubricant supply method, for example, a method of directly pressing and supplying a lubricant to the surface of a photoconductor is described in JP-A-9-62163, and a rotating brush roller is brought into contact with the photoconductor and applied to the brush roller. For example, Japanese Patent Application Laid-Open No. 6-324603 discloses a system in which a lubricant is brought into contact and the lubricant is supplied to a photoconductor via a brush roller. In the latter method, since there are many image forming apparatuses in which a brush roller is provided in a cleaning unit that collects residual toner on the photoconductor, a method of using the brush roller has been proposed.
[0010]
[Problems to be solved by the invention]
In the above image forming apparatus, when supply of the lubricant to the photoconductor is considered, the supply amount of the lubricant is an appropriate amount so that the lubricant does not accumulate on the surface of the photoconductor and problems such as contamination of foreign matter do not occur. Desirably, it is desirable that all of the lubricant is removed after supplying the lubricant on the surface of the photoreceptor and before resupply, and a fresh lubricant is always formed on the surface of the photoreceptor.
[0011]
Here, an appropriate supply amount of the lubricant to the surface of the photoreceptor is determined by a balance between the supply amount and the removal amount of the lubricant removed in the electrophotographic process. Factors for removing the lubricant from the surface of the photoconductor include sliding contact between the developer and the lubricant in the developing unit, scraping of the lubricant with a cleaning blade, and the like, which vary depending on the configuration of the image forming unit. For this reason, the amount of lubricant to be removed differs depending on the configuration of the image forming unit, and it is necessary to set the amount of lubricant to be supplied accordingly.
[0012]
In the tandem-type image forming apparatus, it is desirable that the mechanical configuration of each image forming unit is the same in consideration of the apparatus cost. For this reason, considering only the mechanical configuration, the lubricant removal amount described above is equivalent in each image forming unit, and the lubricant supply amount can be set equally in each image forming unit. However, in a tandem image forming apparatus that mainly forms a color image, black toner, cyan toner, magenta toner, and yellow toner are used as described above, and the contribution of these toners to the lubricant is not exactly the same.
[0013]
More specifically, while cyan toner, magenta toner, and yellow toner have a pigment corresponding to each color added to the base resin, black toner has carbon added to the base resin. For this reason, when the toner is in sliding contact with the surface of the photosensitive member, the black toner to which hard carbon is added has a higher sliding contact capability than other toners, and a large amount of lubricant on the surface of the photosensitive member is scraped off. The effect of extending the service life by supplying the lubricant is diminished.
[0014]
According to the first aspect of the present invention, when a lubricant is supplied to the latent electrostatic image bearing member to extend the life of the latent electrostatic image bearing member, the number of the first latent image bearing member is larger than that of the other image forming portions. To provide an image forming apparatus that does not diminish the effect of extending the life of an electrostatic latent image carrier even if the amount of lubricant removed is large, and can prevent the occurrence of problems due to excessive supply of lubricant. With the goal.
[0015]
The invention according to claim 2 is an effect of extending the life of the electrostatic latent image bearing member of the image forming portion even if the amount of lubricant removed from the image forming portion forming the black image is increased by the carbon contained in the black toner. An object of the present invention is to provide an image forming apparatus capable of preventing the occurrence of problems due to excessive supply of a lubricant without causing the toner to fade.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 visualizes an electrostatic latent image carrier on which an electrostatic latent image is formed, and the electrostatic latent image on the electrostatic latent image carrier. A plurality of image forming units each having a developing device for forming a toner image and a cleaning device for cleaning the electrostatic latent image carrier, and the toner on each electrostatic latent image carrier of the plurality of image forming units an image forming apparatus for transferring a transfer body an image, comprising a plurality of lubricant supply means for supplying a respective lubricant to each of the electrostatic latent image bearing member of the plurality of image forming portions, the plurality of imaging The lubricant supply speed to the photoconductor of the one image forming unit, which has a larger contribution to removing the lubricant from the photoconductor than the other image forming units other than the predetermined one image forming unit of the units, It is configured to be faster than the lubricant supply speed to the photoconductor of the other image forming unit .
[0017]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the plurality of image forming units are image forming units using a black developer, a cyan developer, a magenta developer, and a yellow developer, respectively. The one image forming unit is an image forming unit using a black developer.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows an image forming unit of this embodiment. This embodiment is an embodiment of the invention according to claims 1 and 2. In this embodiment, in the tandem-type image forming apparatus shown in FIG. 3, lubricant application units 30B, 30C, 30M, and 30Y as lubricant supply means are added to the image forming units 1B, 1C, 1M, and 1Y. It has been. The lubricant application portions 30B, 30C, 30M, and 30Y include lubricants 31B, 31C, 31M, and 31Y supported in the cleaning devices 16B, 16C, 16M, and 16Y, and include the cleaning brushes 18B, 18C, 18M, and 18Y. Is to be diverted. The lubricants 31B, 31C, 31M, and 31Y are provided so as to contact the cleaning brushes 18B, 18C, 18M, and 18Y.
[0019]
The cleaning brushes 18B, 18C, 18M, and 18Y are rotationally driven by a driving mechanism (not shown). The lubricants 31B, 31C, 31M, 31Y are scraped off by the cleaning brushes 18B, 18C, 18M, 18Y and adhere to the surfaces of the cleaning brushes 18B, 18C, 18M, 18Y, and then the cleaning brushes 18B, 18C, 18M, 18Y. Is transferred from the cleaning brushes 18B, 18C, 18M, 18Y to the photoconductors 10B, 10C, 10M, 10Y on the surfaces of the photoconductors 10B, 10C, 10M, 10Y when contacting the photoconductors 10B, 10C, 10M, 10Y. Form a layer of lubricant.
[0020]
In the image forming units 1C, 1M, and 1Y that form cyan toner images, magenta toner images, and yellow toner images on the surfaces of the photoreceptors 10C, 10M, and 10Y, brush rollers (cleaning brushes) 18C, 18M, and 18Y are driven by a driving mechanism. The photoconductors 10C, 10M, and 10Y are driven to rotate at an appropriate rotation speed to supply an appropriate amount of lubricant.
[0021]
Further, in the image forming unit 1B that forms a black toner image on the surface of the photoreceptor 10B, the brush roller (cleaning brush) 18B is driven to rotate by the drive mechanism, but as described above, the other image forming units 1C, 1M, Since the toner contributes much more to the lubricant (contributes to removing the lubricant from the photoconductor) than 1Y, the brushes compare to the rotational speeds of the brush rollers 18C, 18M, and 18Y of the other image forming units 1C, 1M, and 1Y. The rotation speed of the roller 18B is increased. For this reason, the supply amount of the lubricant to the photoconductor 10B increases, and the effect of extending the service life by supplying the lubricant to the photoconductor 10B is not diminished. However, as described above, the rotation speed of the brush roller 18B is set to a predetermined rotation speed so as to avoid problems due to excessive supply of lubricant, and the amount of lubricant supplied to the photoconductor 10B is regulated to an appropriate amount.
[0022]
Thus, according to this embodiment, the photosensitive members 10B, 10C, 10M, and 10Y as electrostatic latent image carriers on which electrostatic latent images are formed, and the electrostatic latent image carriers 10B and 10C. The developing devices 13B, 13C, 13M, and 13Y as developing devices that visualize the electrostatic latent images on 10M and 10Y to form toner images, and the electrostatic latent image carriers 10B, 10C, 10M, and 10Y are cleaned. A plurality of image forming units 1B, 1C, 1M, and 1Y having cleaning devices 16B, 16C, 16M, and 16Y, and electrostatic latent image carriers of the plurality of image forming units 1B, 1C, 1M, and 1Y. In the image forming apparatus for transferring the toner images on 10B, 10C, 10M, and 10Y onto a transfer sheet as a transfer body, the electrostatic latent image carriers 10B of the plurality of image forming units 1B, 1C, 1M, and 1Y, 10C, 10M, 10 Includes lubricant application sections 30B, 30C, 30M, and 30Y as lubricant supply means for supplying a lubricant to the plurality of image forming sections 1B, 1C, 1M, and 1Y from the lubricant supply means 30B. The amount of lubricant supplied to the electrostatic latent image carrier 10B of one predetermined image forming unit 1B of the plurality of image forming units 1B, 1C, 1M, and 1Y from the lubricant supplying means 30C, 30M, and 30Y. Since it is configured to be larger than the amount of lubricant supplied to the electrostatic latent image carriers 10C, 10M, 10Y of the image forming units 1C, 1M, 1Y other than the one image forming unit 1B, When the lubricant is supplied to the image carrier to extend the life of the electrostatic latent image carrier, the electrostatic charge can be increased in one image forming unit even if the amount of lubricant removed is larger than in other image forming units. The effect of extending the life of the latent image carrier is not diminished, and the lubricant is excessively supplied. It is possible to prevent the occurrence of the condition.
[0023]
Further, according to this embodiment, the plurality of image forming units 1B, 1C, 1M, and 1Y are image forming units that use a black developer, a cyan developer, a magenta developer, and a yellow developer, respectively. Since one image forming unit 1B is an image forming unit that uses a black developer, even if the amount of lubricant removed from the image forming unit that forms a black image increases due to carbon contained in the black toner, The effect of extending the life of the electrostatic latent image carrier is not diminished, and the occurrence of problems due to excessive supply of lubricant can be prevented.
[0024]
The present invention is not limited to the above embodiment. For example, after the toner image on the electrostatic latent image carrier of each image forming unit is transferred onto the intermediate transfer member as a transfer member, The present invention can also be applied to an image forming apparatus that transfers to transfer paper. In the above embodiments, the drum-shaped photoconductor is used. However, the present invention can also be applied to an image forming apparatus using a belt-shaped photoconductor or a sheet-shaped photoconductor.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, when a lubricant is supplied to the electrostatic latent image carrier to extend the life of the electrostatic latent image carrier, Even if the removal amount of the lubricant is larger than that in the image forming portion, the effect of extending the life of the electrostatic latent image carrier is not diminished, and the occurrence of problems due to excessive supply of the lubricant can be prevented.
[0026]
According to the second aspect of the present invention, the life of the electrostatic latent image carrier of the image forming unit is increased even if the amount of lubricant removed from the image forming unit that forms the black image increases due to the carbon contained in the black toner. The effect of this is not diminished and the occurrence of problems due to excessive supply of lubricant can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing one image forming unit of the embodiment.
FIG. 3 is a cross-sectional view illustrating an example of a color image forming apparatus.
FIG. 4 is a cross-sectional view showing one image forming unit in the color image forming apparatus.
[Explanation of symbols]
1B, 1C, 1M, 1Y Image forming units 10B, 10C, 10M, 10Y Photoconductors 13B, 13C, 13M, 13Y Developers 16B, 16C, 16M, 16Y Cleaning devices 30B, 30C, 30M, 30Y Lubricant application unit

Claims (2)

An electrostatic latent image carrier on which an electrostatic latent image is formed, a developing device that visualizes the electrostatic latent image on the electrostatic latent image carrier to form a toner image, and the electrostatic latent image carrier An image forming apparatus comprising a plurality of image forming units each having a cleaning device for cleaning a body, wherein the plurality of image forming units transfer a toner image on each electrostatic latent image carrier to a transfer body. a plurality supplies each lubricant to each of the electrostatic latent image bearing member of the image forming unit lubricant comprises a supply means, said plurality of predetermined one other than the image forming portion of one of the image forming unit The lubricant supply speed to the photoconductor of the one image forming unit is larger than the lubricant supply rate to the photoconductor of the other image forming unit, which has a larger contribution to removing the lubricant from the photoconductor than the image forming unit. An image forming apparatus having a fast configuration .   2. The image forming apparatus according to claim 1, wherein the plurality of image forming units are image forming units using a black developer, a cyan developer, a magenta developer, and a yellow developer, respectively, and the one image forming unit includes: An image forming apparatus comprising an image forming unit using a black developer.

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