JPH05107988A - Cleaning device - Google Patents

Abstract

PURPOSE:To attain miniaturization and reduction in cost, simultaneously, to efficiently remove the toner of different characteristics, and to improve cleaning properties. CONSTITUTION:A fur brush 16 electrostatically scraping the toner on a photosensitive body 2, a recovery roller 17 recovering the toner stuck to the fur brush 16, and a set of scrapers 18 removing the toner stuck to the recovery roller 17, are provided. A mode for consecutively executing a cleaning process plural times, is provided. The polarity of a voltage applied to the fur brush 16 and the recovery roller 17 is reversed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention cleans untransferred toner remaining on a photoconductor of an electrophotographic apparatus such as a copying machine, a printer or a facsimile machine by electrostatic attraction with a conductive fiber planting brush (fur brush). The present invention relates to a cleaning device configured to do so.

[0002]

2. Description of the Related Art Generally, in an electrophotographic apparatus, an electrostatic latent image is formed on a photoconductor and toner is attached to the electrostatic latent image to form a toner image based on an original image.
Since the untransferred toner usually remains on the photosensitive member after the toner image is transferred onto the transfer paper, it is necessary to clean the untransferred toner before the next process operation.

There is an electrostatic brush cleaning device as a cleaning device for cleaning the toner on the photosensitive member. As one of the electrostatic brush cleaning devices, a method in which voltages of positive polarity and reverse polarity are applied to two fur brushes to simultaneously remove the positive polarity toner and the negative polarity toner remaining on the photoconductor There is. However, in the case of this method, two fur brushes are required, and the entire cleaning device becomes large.
A fur brush is provided with two conductive flocking areas separated by two insulating flocking areas, one conductive area is applied with a positive voltage and the other conductive area is applied with a negative voltage, and one fur brush is used. A method has been proposed in which positive and negative polar toners can be adsorbed to reduce the size (Japanese Patent Publication No. 1-38314).

[0004]

However, in the case of the system proposed above, the fur brush itself, the bias applying mechanism, etc. are complicated and therefore expensive, and at least two collecting rollers and scrapers are required. Therefore, there is a limit to downsizing, and when the scraper is a consumable item, the replacement cycle is the same and the work is doubled.

Further, when the color brush is used in a color electrophotographic apparatus of the type in which color toners are superposed on a photoconductor and are collectively transferred to a transfer paper, a fur brush alone has a plurality of different types of untransferred characteristics. Since the toner has to be cleaned at one time, it is difficult to optimize the bias conditions, and the amount of untransferred toner remaining is large, so the load on cleaning is large.

Therefore, the present invention is intended to provide a cleaning device which can reduce the size and cost and can efficiently remove color toners having different characteristics.

[0007]

In order to solve the above problems, the present invention provides a fur brush for electrostatically scraping off untransferred toner remaining on a photoconductor of an electrophotographic apparatus, and a fur brush attached to the fur brush. A cleaning device having a collecting roller for electrostatically collecting the collected toner and a scraper for scraping off the toner attached to the collecting roller is provided with a mode in which the photosensitive member cleaning step is continuously performed a plurality of times, and the cleaning step 1 The polarity of the voltage applied to the fur brush and the collecting roller is reversed every time.

Further, in the case of a color electrophotographic apparatus, a mode is provided in which the photosensitive member cleaning step is continuously performed a plurality of times only when forming a color image, and the fur brush and the collecting roller are applied every cleaning step. It is preferable that the polarity of the applied voltage be reversed.

Further, the voltage value applied to the fur brush and the collecting roller may be changed each time the photosensitive member cleaning step is performed in the plural times mode.

When a cleaning blade is provided in addition to the fur brush or the like, the voltage applied to the fur brush has a reverse polarity after the transfer paper is separated from the photoconductor and the untransferred toner passes through the position of the cleaning blade. At the same time, the cleaning blade may be separated from the surface of the photoconductor, and the machine may be stopped after the photoconductor makes one rotation or more.

[0011]

It is possible to remove both the positively charged toner and the oppositely charged toner with a simple structure by combining a pair of fur brushes, a collection roller and a scraper, and it is possible to reduce the size and cost.

Further, if the cleaning is performed a plurality of times only in the color image mode, the printing efficiency can be improved while the cleaning performance is improved.

Further, if the bias value is changed every cleaning, the color toners having different characteristics can be efficiently removed.

Further, in a cleaning device having a cleaning blade together with the fur brush, the voltage of the fur brush is set to the opposite polarity after the transfer paper has passed, and the cleaning blade is moved away from the photoconductor to rotate the photoconductor more than once. By doing so, it is possible to remove the foreign matter accumulated on the edge of the cleaning blade, and also to re-adhere the toner on the fur brush to the photoconductor, so that the fur brush can be cleaned.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows an example of a color laser printer, and an image is formed by the following process.
That is, the photosensitive member 2 charged by the charging charger 1 is subjected to scanning exposure with a black image signal by the optical writing unit 3 to form a negative electrostatic latent image, and the electrostatic latent image has a yellow (Y) color. , A magenta (M), a cyan (C), and a black (BL) color toner are brought into contact with each other to form a toner image. At this time, the toner other than black is adjusted so as not to fly. Next, static elimination / P
The electrostatic charge image on the photoconductor 2 is removed by the CC charger 5. At this time, the cleaning device 6 is separated from the photoconductor. Next, by the same method as the method for forming a black (BL) toner image, the processes of charging, exposing, developing, and neutralizing are repeated, and yellow (Y), magenta (M), and cyan (C) are formed on the photoconductor 2. After the toner images are sequentially superposed and all the toner development is completed, the transfer paper 9 supplied from the cassette 7 by the paper feed roller 8 is superposed on the toner image at a timing by the registration roller 10 and transferred. The toner image is electrostatically transferred onto the transfer paper 9 by the charger 11, and then the transfer paper 9 on which the image is fixed by the fixing device 12 is ejected onto the paper ejection tray 14 by the paper ejection roller 13. On the other hand, the untransferred toner remaining on the photoconductor 2 after the electrostatic transfer is removed by the cleaning device 6 in contact with the photoconductor 2 so that one cycle of color image formation is completed. The cleaning device 6 separates from the photoconductor 2 again after cleaning the untransferred toner image. In addition, 15 shows an outer cover.

The cleaning device 6 in such a color laser printer is constructed as shown in FIGS. That is, a fur brush 16 in the form of a roller in which conductive fibers are planted is formed to electrostatically scrape off untransferred toner remaining on the photoconductor 2, and the toner attached to the fur brush 16 is electrostatically removed. Collecting roller 17 disposed so as to be absorbed into the fur brush 16 by 1-2 mm so as to be sucked and collected, a scraper 18 for scraping off the toner adhering to the collecting roller 17, and a toner scraped off by the scraper 18. And a recovery coil roller 19 for conveying the toner to the outside of the cleaning casing 20, and a spring 21 stretched between the main body portion and the casing 20 so as to separate the fur brush 16 from the photoconductor 2 when the color image is superimposed.
And the casing 2 around the shaft 22 after the toner image is transferred.
The fur brush 16 is moved to the photosensitive member 2 by rotating 0.
Mode in which the photoconductor cleaning step is continuously performed a plurality of times only during color image formation in a configuration having an eccentric roller 24 rotatably contacting a leaf spring 23 attached to the outer wall portion of the casing 20 so as to abut against the And the polarity of the voltage applied to the fur brush 16 and the collecting roller 17 is reversed every time the cleaning process is performed, and when a color image is superimposed on the photoconductor 2, As shown in FIG. 2, the fur brush 16 is at the waiting position, and after the toner image on the photoconductor 2 is transferred onto the transfer paper 9, the eccentric roller 24 is rotated 180 ° from the state of FIG. By rotating the casing 20 counterclockwise in the figure about the shaft 22 against the spring 21 and bringing the fur brush 16 into contact with the photoconductor 2 as shown in FIG. So as to clean Te, after completion of the cleaning is to return again to the stand-by position the fur brush 16 by further rotating 180 ° an eccentric roller 24. The photoconductor 2 of the fur brush 16
The amount of bite into the eccentric roller 24 is maintained by the gap rollers (not shown) provided at both ends of the shaft 25 of the eccentric roller 24 contacting the photoconductor 2. Further, the leaf spring 23 serves to press the gap roller against the photoconductor 2.

Next, the cleaning device 6 having the above structure
The state of toner removal by means of will be described with reference to FIGS.

As shown in FIG. 4, the untransferred toner remaining on the photoconductor 2 after being transferred onto the transfer paper is neutralized by P.
The CC charger 5 charges the positive DC voltage and the positive AC voltage to uniformly charge the positive polarity (negative charging in the embodiment). At this time, a positive DC voltage + V ₁ (usually about +200 to +300 V) is applied to the fur brush 16. Therefore, the positive toner 26a that has entered the cleaning device 6 is electrostatically adsorbed while being scraped off by the fur brush 16. At this time, the collection roller 1
Since a higher voltage (about +300 to +500 V) is applied to 7, the positive polarity toner 26a moves from the fur brush 16 to the collecting roller 17 and adheres to the collecting roller 17, and is scraped off by the scraper 18 to collect the collecting coil roller 19. Is discharged to the outside of the casing 20.

In the above description, there is not much transfer residual toner in the case of monochromatic development, but in the case of color image formation, the photoconductor 2 is used.
Since two to four types of toner are superposed on each other at the same time, the amount of transfer residual toner is large. Therefore, even after cleaning
A large amount of reverse polarity toner 26b is difficult to remove with the above cleaning bias. Therefore, at the time of color development, after cleaning the positive polarity toner 26a, the photosensitive member 2 is rotated again to remove the reverse polarity toner 26b. In this case, as shown in FIG. 5, a negative DC voltage −V ₁ is applied to the fur brush 16 to adsorb the reverse polarity toner 26b entering the fur brush 16. At this time,
The collecting roller 17 in advance by applying a higher voltage -V ₂ than fur brush 16, thereby collecting the toner 26b on the fur brush 16 by the recovery roller 17.

As described above, in the same cleaning device 6, the polarities of the voltages applied to the fur brush 16 and the collecting roller 17 are reversed, and the photosensitive member is cleaned twice, so that a low cost, small size, and good cleaning effect can be obtained. can get. In addition, in a monochrome printer or copier,
Similarly, cleaning may be performed twice.

By the way, the bias voltages V ₁ and V ₂ are closely related to the toner characteristics, and the optimum values differ depending on the toner characteristics. Therefore, in order to clean a plurality of types of toner at once, it is possible to remove the toner more efficiently if cleaning is performed with a bias value suitable for each characteristic. Therefore, in the present invention, the photosensitive member 2 is cleaned a plurality of times only during the color image transfer, and the bias voltage (current) is controlled to the optimum value for each toner. As a result, the reversely charged toner can also be removed by the reverse bias, so that good cleaning performance can be obtained.

Next, FIG. 6 shows another embodiment of the present invention. The photoconductor 2 is located downstream of the fur brush 16 in the moving direction of the photoconductor 2 with respect to the cleaning device 6 in the above-mentioned embodiment. A cleaning blade 27 arranged so that the edge 27a contacts the surface of the
Further, after the transfer paper is separated from the photoconductor 2 and the untransferred toner 26 passes the position of the cleaning blade 27, the voltage applied to the fur brush 16 is set to the opposite polarity and the cleaning blade 27 is separated from the photoconductor 2. The machine is stopped after the photoconductor 2 has rotated once or more.

With this configuration, the fur brush 16 can be cleaned and durability can be improved, and at the time of replacement of the fur brush 16, toner drop, scattering, and dirt can be prevented. . Further, by releasing the blade 27, the foreign matters (paper dust and the like) accumulated in the blade edge 27a and the toner 26 can be released to maintain the cleaning performance, and by applying a reverse bias to the fur brush 16, the fur brush is applied to the photoconductor 2. The toner 26 on the brush 16 can be re-adsorbed to prevent the adsorption of paper dust that tends to adhere to the photoconductor 2 and to suppress the generation of black spots.
Since the toner 26 is present on the upper side, it is effective in preventing the blade 27 from being caught or chipped.

The embodiment of FIG. 6 will be described in detail. In the cleaning device using the fur brush 16 as described above, in order to maintain the function of the photoconductor 2 for a long time, the toner 26 attached to the photoconductor 2 is used. To remove the toner 26 from the fur brush 16 onto the photoconductor 2 as much as possible, and to prevent toner filming on the photoconductor 2 and fine paper dust as much as possible. The ability such as that is required.

The most effective measure for increasing the removal ability of the toner 26 is to increase the bias voltage applied to the fur brush 16, and this way, the fur brush 26 side will be applied to the photosensitive member. The residual toner 26 is subjected to charge injection and the like, the polarity of the toner 26 is reversed, and the toner 26 once attached to the fur brush 16 reattaches to the photoconductor 2 to form an image on the image. It is easy for soil stains to occur.

This is because the smooth end of the fur brush 16 in which the fibers are cut rubs against the photosensitive member, so that the edge portion of the end is apt to leak, and the charge to the toner is charged. It is considered that this is due to the fact that the injection is easily performed, or that the contact charging is likely to occur between the smooth end portion.
In fact, when the fur brush 16 is new, such a tendency becomes remarkable, and as the fur brush 16 is used for a long period of time, the end edge portion of the brush fiber is worn out in an R shape, and gradually. The charge injection described above is less likely to occur.

Therefore, in the present invention, as described above, the rear end of the transfer paper passes through the photoconductor 2 and the untransferred toner 26
After passing through the cleaning blade 27, the DC power source E ₁ ,
By setting the polarity of E ₂ to the opposite polarity (negative power source in the figure), the cleaning blade 27 is disengaged from the photoconductor 2, and the machine is stopped after the photoconductor 2 rotates for one rotation or more. After that, the toner 26 in the fur brush 16 is applied to the photoconductor 2 by electric potential to clean it, and at the same time, the toner 26 accumulated on the blade edge 27a portion, foreign matter such as paper dust, and the like are used to prevent medaka.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0029]

As described above, according to the present invention, a fur brush that electrostatically scrapes off untransferred toner remaining on the photoconductor of an electrophotographic apparatus, and a toner that adheres to the fur brush are electrostatically removed. In a cleaning device having a collecting roller for collecting the toner and a scraper for scraping off the toner adhering to the collecting roller, a mode is provided in which the photoconductor cleaning step is continuously performed a plurality of times, and the cleaning step is performed once for each cleaning step. Since the polarity of the voltage applied to the fur brush and the collecting roller is reversed, both the positively charged toner and the reversely charged toner can be removed with a simple structure of one set of the fur brush, the collecting roller and the scraper, and the entire apparatus can be removed. Miniaturization and cost reduction can be achieved.

Further, in the case of a color electrophotographic apparatus, a mode is provided in which the cleaning process is continuously performed a plurality of times only when forming a color image, and each cleaning process is performed once.
The cleaning performance can be improved by making the voltage applied to the fur brush and the collecting roller reverse. That is, 1 in the black image (single color) mode
Since the cleaning process is performed once, the performance can be improved and the printing efficiency can be improved as compared with the case of cleaning the black image a plurality of times.

Further, the value of the voltage applied to the fur brush and the collecting roller is changed for each cleaning step performed in the plural times mode.
Color toners having different characteristics can be efficiently removed.

Furthermore, in a cleaning device having a cleaning blade, the voltage applied to the fur brush is reversed in polarity after the transfer paper leaves the photosensitive member and the untransferred toner passes through the position of the cleaning blade. At the same time, the cleaning blade is separated from the surface of the photoconductor, and the machine is stopped after the photoconductor makes one rotation or more. It has an excellent effect that it can be adhered to the blade to clean the fur brush and can remove foreign matters such as toner and paper dust accumulated in the blade edge portion.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a color laser printer showing an example of an electrophotographic apparatus.

FIG. 2 is a schematic view showing an embodiment of a cleaning device of the present invention.

FIG. 3 is a schematic view showing an operating state different from that in FIG.

FIG. 4 is a schematic view showing a state in which positive polarity toner is adsorbed and removed.

FIG. 5 is a schematic view showing a state in which reverse polarity toner is adsorbed and removed.

FIG. 6 is a schematic view showing another embodiment of the present invention.

[Explanation of symbols]

 2 Photoconductor 6 Cleaning Device 9 Transfer Paper 16 Fur Brush 17 Collection Roller 18 Scraper 26 Toner 27 Cleaning Blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Naomi Misasa Inoue Nakamagome 1-3-6, Ota-ku, Tokyo Stock company Ricoh Co., Ltd. (72) Arai Makoto Nakamagome 1-3-6, Ota-ku, Tokyo Stocks In Ricoh Company (72) Inventor Sadao Takahashi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Masaru Tanaka 1-3-6 Nakamagome, Ota-ku, Tokyo In-Ricoh Company ( 72) Inventor Toshitaka Yamaguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (4)

[Claims] 1. A fur brush that electrostatically scrapes untransferred toner remaining on a photoconductor of an electrophotographic apparatus, a collecting roller that electrostatically collects toner attached to the fur brush, and a collecting roller. In a cleaning device having a scraper for scraping off the toner adhered to the toner, a mode is provided in which the photosensitive member cleaning step is continuously performed a plurality of times, and the polarity of the voltage applied to the fur brush and the collecting roller is set for each cleaning step. A cleaning device characterized by being configured so as to reverse. 2. A non-transferred toner remaining on a photoconductor in a color electrophotographic apparatus, which is formed by superposing a plurality of toner images of different colors on the photoconductor and then collectively transferring the toner images onto a transfer paper. When a color image is formed in a cleaning device having a fur brush that scrapes electrostatically, a collecting roller that electrostatically collects toner that adheres to the fur brush, and a scraper that scrapes off toner that adheres to the collecting roller A mode is provided in which only the photoreceptor cleaning process is continuously performed a plurality of times, and each cleaning process is performed once.
A cleaning device configured to reverse the polarities of the voltages applied to the fur brush and the collecting roller. 3. The cleaning device according to claim 2, wherein the voltage value applied to the fur brush and the collecting roller is changed every time the photoconductor cleaning step is performed in a plurality of times. 4. A fur brush for electrostatically scraping off untransferred toner remaining on a photoconductor of an electrophotographic apparatus, a collecting roller for electrostatically collecting the toner attached to the fur brush, and a collecting roller. In a cleaning device having a scraper for scraping off the toner adhering to the photoconductor and a cleaning blade arranged in contact with the surface of the photoconductor on the downstream side of the fur brush in the photoconductor moving direction, the transfer paper is not detached from the photoconductor and After the transfer toner has passed the position of the cleaning blade, the voltage applied to the fur brush has a reverse polarity, the cleaning blade is separated from the photosensitive member, and the machine is stopped after one rotation of the photosensitive member or more. A cleaning device characterized by the above.