US3871081A

US3871081A - Cleaning equipment for electrophotography

Info

Publication number: US3871081A
Application number: US052926A
Authority: US
Inventors: Shozo Inoue; Akira Kurahashi
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1969-07-14
Filing date: 1970-07-07
Publication date: 1975-03-18
Anticipated expiration: 1992-03-18
Also published as: DE2034955C3; DE2034955A1; DE2034955B2

Abstract

A cleaning equipment for electrophotographic apparatus of imagetransferring type comprises a cleaning means rubbing a photosensitive member after an image thereon has been transfered to another member and a means for feeding a cleaning solution.

Description

United States Patent [191 lnoue et al.

[ Mar. 18, 1975 CLEANING EQUIPMENT FOR ELECTROPHOTOGRAPHY [75] Inventors: Shozo lnoue; Akira Kurahashi, both of Tokyo, Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo,

Japan [22] Filed: July 7, 1970 [21] Appl. No.: 52,926

[30] Foreign Application Priority Data July 14, 1969 Japan 44-67249[U] July 14, 1969 Japan 44-6725l[U] July 14, 1969 Japan 44-67252[U] July 14, 1969 Japan 44-67253[U] [52] US. Cl. 15/256.5l [51] Int. Cl A46b 15/00 [58] Field of Search 118/637, DIG. 23; 15/210, 15/256.5l, 256.52, 100, 1.5, 4; 355/15 [56] References Cited UNITED STATES PATENTS 2,987,660 6/1961 Walkup 15/25651 3,186,838 6/1965 Graff, Jr. et al. l5/l.5 X 3,384,051 5/1968 Hunstiger 118/637 LX 3,526,457 9/1970 Dimond et al. 15/].5 X

Primary Examiner-Robert L. Bleutge Assistant Examiner-C. K. Moore Attorney, Agent, or Firm-Fitzpatrick, Cella, Harper & Scinto [57] ABSTRACT A cleaning equipment for electrophotographic apparatus of image-transferring type comprises a cleaning means rubbing a photosensitive member after an image thereon has been transfered to another member and a means for feeding a cleaning solution.

6 Claims, 5 Drawing Figures CLEANING EQUIPMENT FOR ELECTROPIIOTOGRAPHY BACKGROUND OF THE INVENTION 1. Field of the invention This invention relates to cleaning equipment of an electrophotographic photosensitive member. More particularly, it relates to cleaning equipment which removes the toner still remaining on the photosensitive member after the image thereon has been transfused in an electrophotography system which is capable of obtaining copied images by repeated use of the photosensitive member.

2. Description of the Prior Art Conventional cleaning means for transfer systems for electrophotography are:

a. A means that wipes away the toner by making a rotary brush contact with the photosensitive member;

b. A means that removes the toner by pressing weblike paper to the photosensitive member and by winding up the paper sequentially; and

c. A means that removes the toner by pressing a flexible roller against the photosensitive member to make contact with it.

However, in an electrophotographic system in which a photosensitive member comprising a surface insulating layer, a conductive or insulating layer, and a photoconductive layer which is sandwiched between said two layers is used and an electrostatic latent image having such high surface potential as several hundred volts to two kilovolts is obtained, the cleaning means (a) and (b) as mentioned above fail to provide perfect cleaning. The disadvantage with the means (c) is that it has a large possibility of damaging the photosensitive member because it requires an extremely large pressing force.

An object of this invention is to offer simple cleaning equipment capable of removing the toner remaining after transferring, the toner being adsorbed and held by the partially high surface potential as described above. Of course, this invention is not limited to the abovementioned electrophotography, but is effectively applied to other known electrophotographic systems now in practical use.

SUMMARY OF THE INVENTION The invented equipment is electrophotographic cleaning equipment which is provided with a cleaning means capable ofslidably contacting the photosensitive member and a means to supply cleaning solution for the purpose of increasing the cleaning effect of the above-mentioned cleaning means. It removes the toner remaining on the photosensitive member after transferring the image that has been developed on the surface of the photosensitive member of transferring electrophotographic copying equipment.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 through show the electrophotographic copying equipment provided with embodiments of this invention, respectively. FIG. 1 shows the case in which a cleaning roller is employed. FIGS. 2 and 5 show the case in which the web is used. FIGS. 3 and 4 show the case in which a cleaning belt is employed.

DESCRIPTION OF HE PREFERRED EMBOD ENTS Embodiments of this invention will be described hereinafter referring to the drawings.

Electrophotographic copying equipment, to which this invention may be applied, is shown in FIG. 1. A photosensitive member 1 is composed of a surface insulating layer 1,, a photoconductive layer 1 and an insulating or conductive layer I and is mounted around the outer surface of a drum to be rotated to the direction of the arrow. Each processing device of electrophotography is installed around the aforementioned photosensitive member. The photosensitive member is charged by a primary charger 2, and then subjected to charging to a polarity opposite to that of the primary charging or to AC charging and contemporaneous irradiation of original image from the charging exposer 3.

The photosensitive member is subjected to whole surface exposure by a light source 4 to increase the contrast of the latent image which is then visualized by the developing instrument 5.

The developing method may either be a dry method such as a magnet brush, a fur brush, or a cascade method, or a wet method using liquid developing agents.

For the purpose of increasing the transferring effect, the photosensitive member is subjected to charging by the tertiary charger 6 when required. The visible image on the photosensitive member is then transferred to a transfer material 7 by means of a transfer roller 8, and fixed to form a permanently fixed image by a fixing instrument 9. Thus, a transferred copy is obtained.

The toner, with a high surface potential, still remains on the surface of the photosensitive member at the visible image area. This toner must be removed completely by means of cleaning.

This invention is an improvement of the cleaning equipment. As shown in FIG. 1, the equipment of this invention is provided with a cleaning roller 10, which cleans the photosensitive member 1 after completing the image transfer, an auxiliary cleaning member 11 capable of contacting the aforementioned roller 10, and a means jeting out a cleaning solution 12 to the neighborhood of the contacting place of the roller 10 and the member 11. The cleaning roller 10 is either an elastic roller made of rubber, polyurethane foam or a roller covered with cloth or leather which is made to turn relative to the photosensitive member 1. The auxiliary cleaning member 11 is preferably a brush roller or the like which rotates in a direction opposite to that of the aforementioned roller 10. As cleaning solution, there may be used water, alcohol, or solvents of petroleum origin, for example, those having the trade names Isopar G and H. The means for jeting out the cleaning solution 12 includes a pump 13 and a discharge pipe 14. Discharge pipe 14 jets out the cleaning solution 12 from below the contacting point of the roller 10 and the member 11. The cleaning solution containing the toner falls down into the tank and then flows into the compartment B and then enters the compartment A through a mesh electrode 16 leaving the filtered toner in the compartment 8. From the compartment A, the refreshed toner is again sent to the discharge tube 14 by the pump 13 to be recirculated. In the abovementioned means, the cleaning roller 10 has its toner scraped off by the auxiliary cleaning member 11. simultaneously the roller receives a supply of cleaning solution 12 and, when required, is squeezed by the squeezing roller 17 so that it contains an appropriate amount of moisture. The cleaning roller 10 then makes a slidable contact with the photosensitive member 1 and, while wiping away the excessive toner, removes the toner by adsorbing it through the adhesiveness of the cleaning solution. Therefore, it is possible to remove surely and easily the toner, that has a high surface potential, that adheres to the photosensitive member 1, by only pressing the aforementioned roller 10 lightly onto the photosensitive member 1 and by rotating the roller 10. This electrophotographic cleaning equipment does not damage the photosensitive member. Therefore, the cleaning equipment of this invention is very useful. In the case of a cleaning solution of poor volatility, it is possible to eliminate the trouble in the next charging process by installing an elastic moisture absorbing roller 18 made of cloth or polyurethane foam immediately behind the above-mentioned cleaning equipment to remove the moisture of the photosensitive member 1 or by blowing hot air onto the photosensitive member 1.

The second embodiment of this invention is shown in FIG. 2. This embodiment consists of a means for supplying a cleaning solution 12 to the surface of the photosensitive member after effecting image formation in a way similar to the process of the previously mentioned embodiment and after completing the transferring process and a means for cleaning the surface of the photosensitive member thereafter by wiping. The cleaning solution delivery means shown here has a configuration in which cleaning solution 12 in atank is sprayed onto the photosensitive member 1 by pump 13 through a discharge tube 14. The wiping means includes a web 23 of cloth, paper, or synthetic resin such The third embodiment is shown in FIG. 3. Using the process similar to that of the first embodiment, the image is formed and transferred. In this embodiment, the cleaning belt 25, which makes a light contact with the surface of the photosensitive member 1 and moves relatively therewith, is hung across the drive roller 26 and support roller 27. One portion of the belt 25 is immersed in the cleaning solution 12, and the absorbed cleaning solution 12 is squeezed from the belt 25 appropriately by the squeezing roller 28, and the belt 25 containing cleaning solution 12 wipes the surface of the photosensitive member to remove the remaining toner. Accordingly, the photosensitive member 1 is rubbed by portion of the belt 25 containing an appropriate amount of cleaning solution 12, and the remaining toner is wiped and, simultaneously removed by the adhesion of the cleaning solution. Furthermore, when a conductive cleaning solution is used, the potential of the toner sticking to the photosensitive member with partially high potential is reduced and the toner is easily removed from the photosensitive member. The cleaning belt 25 with the toner attached thereto is washed in the tank of cleaning solution 12 and, when required, is squeezed by elastic squeezing roller 28. After the toner has been removed, the cleaning belt 25 contacts the photosensitive member again. The cleaning efficiency can be increased by applying an electric field having a polarity opposite to that of the toner to the contacting position through a discharger 29.

FIG. 4 illustrates the fourth embodiment of this invention. This cleaning equipment includes'an endless cleaning belt 25 having cloth or elastic rubber. The endless cleaning belt 25 slidably contacts photosensitive member 1, moves relatively, and enters cleaning solution 12 in a cleaning solution reservoir. 15. An auxiliary cleaning member 11 fitted to the reservoir 15 slidably contacts cleaning belt 25, and an electrode 16 for purifying the cleaning solution is fitted in the reservoir 15. When the belt 25 is moved relatively to the photosensitive member 1, the belt is impregnated with the cleaning solution 12, leaves the tank and, after being squeezed properly by the squeezing rollers 17, makes a slidable contact with the photosensitive member 1. There, by the cleaning function of the belt 25 and the stickiness of the cleaning solution 12, the toner sticking to the photosensitive member by the aforementioned high surface potential is easily removed, sticks to the belt 25 and led to the cleaning solution 12 of the tank 15. The toner is scraped off from the belt 25 in the tank by the member 11 and the belt 25 absorbs the cleaning solution again and starts the next cycle of operation. Thus the belt 25 can be used repeatedly. The toner in the tank 15 is adsorbed by the mesh electrode electrically. The cleaning solution thus purified is moved from the compartment B to compartment A where it is made to circulate to the compartment B' by way of pump 13 and discharge tube 14. The belt may be a flexible metal belt covered with cloth, leather, or the like. The cleaning solution 12 can be either water, alcohol, or petroleum origin solvent (for example, the ones having trade names Isobar H and G) used in liquiddeveloping agents. In other words, the cleaning solution may be either conductive or insulating. When using a cleaning solution of poor volatility, it is a good practice to wipe away the moisture from the surface of the photosensitive member after cleaning with a roller 18 made of cloth, polyurethane foam etc., or to dry the surface of the photosensitive member by blowing hot air.

Further, the fifth embodiment of this invention is illustrated in FIG. 5. In this cleaning equipment, a cleaning web 23 having paper or cloth is pressed lightly against the photosensitive member 1 after finishing the transferring process, and moved relatively to the photosensitive member 1, and the cleaning solution 12 is supplied by elastic roller 31 pressing the web 23. In the example shown in the drawing, the above-mentioned solution staying in the tank 15 is sprayed to the supply roller 34 by way of pump 13 and discharge tube 14 and is further supplied to elastic roller 31 by way of roller 33. However, the cleaning solution 12 may be supplied by directly dipping the supply roller 34 in the cleaning solution. The elastic roller 31 is made of rubber, polyurethane foam etc. According to this embodiment, the cleaning solution 12 is supplied from the elastic roller 31 to the back side of hygroscopic web 23 made of materials such as cloth or paper, and the properly moistened web 23 rubs the surface of the photosensitive member. Therefore, the toner sticking to the photosensitive member with a high surface potential can be easily removed. The web 33 may be used only once or reused after cleaning.

What is claimed is:

1. Cleaning equipment for use in an electrophotographic apparatus of the transferring type wherein an electrostatic latent image is formed on a photosensitive member and developed and then the developed image is transferred to a transferring material and, thereafter, the residual toner on the surface of the photosensitive member is cleaned off the repetitive use, said equipment comprising means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing which is positioned between a transferred process and a charging process to effect said cleaning prior to charging, said means for cleaning a photosensitive member by rubbing comprising a roller and an auxiliary cleaning member which is contacted with said roller so as to eliminate the toner adhering thereto, and said means for supplying a cleaning solution being positioned to apply the cleaning solution in the proximity of the contact between said roller and said auxiliary cleaning member.

2. Cleaning equipment for use in an electrophotographic apparatus of the transferring type wherein an electrostatic latent image is formed on a photosensitive member an developed and then the developed image is transferred to a transferring material and, thereafter, the residual toner on the surface of the photosensitive member is cleaned off for repetitive use, said equipment comprising means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing which is positioned between a transferring process and a charging process to effect said cleaning prior to charging, said means for cleaning a photosensitive member by rubbing comprising a cleaning web which moves relatively to the photosensitive member and then rubs thereon, and said means for supplying a cleaning solution comprising an elastic roller feeding a cleaning solution to the backside of the web.

3. Cleaning equipment for use in an electrophotographic apparatus of the transferring type wherein an electrostatic latent image is formed on a photosensitive member and developed and then the developed image is transferred to a transferring material and, thereafter, the residual toner on the surface of the photosensitive member is cleaned off for repetitive use, said equipment comprising means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing which is positioned between a transferring process and a charging process to effect said cleaning prior to charging, said means for supplying a cleaning solution and said means for cleaning a photosensitive member by rubbing comprising a tank for containing a cleaning solution, mounted adjacent said photosensitive member, a mesh electrode dividing said tank into a first compartment and a second compartment, a cleaning roller mounted over the first compartment of said tank for rubbing engagement with said photosensitive member, said cleaning roller being movable in a direction opposite to the movement of said photosensitive member, an auxiliary cleaning member mounted for engagement with said cleaning roller, a pump in said second compartment, said pump having a discharged pipe which extends to a position adjacent said cleaning roller and said auxiliary cleaning member for jetting out a cleaning solution in the neighborhood of the contacting point between said auxiliary cleaning member and said cleaning roller, and a squeezing roller for engaging said cleaning roller subsequent to said auxiliary cleaning member.

4. Cleaning equipment according to claim 3, further comprising an elastic moisture absorbing roller mounted for engaging said photosensitive member subsequent to said cleaning roller.

5. Cleaning equipment for use in an electrophotographic apparatus of the transferring type wherein an electrostatic latent image is formed on a photosensitive member and developed and then the developed image is transferred to a transferring material and, thereafter, the residual toner on the surface of the photosensitive member is cleaned off for repetitive use, said equipment comprising means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing which is positioned between a transferring process and a charging process to effect said cleaning prior to charging, said means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing comprising a tank for containing cleaning solution mounted adjacent said photosensitive member, a pump mounted in said tank, said pump having a discharge tube extending to a position adjacent said photosensitive member for spraying cleaning solution onto said photosensitive member, an elongated web mounted adjacent said photosensitive member for movement from a supply reel to a takeup reel in a direction opposite to the movement of said photosensitive member, and an elastic roller adjacent said web for urging said web into rubbing engagement with said photosensitive member.

6. Cleaning equipment for use in an electrophotographic apparatus of the transferring type wherein an electrostatic latent image is formed on a photosensitive member and developed and then the developed image is transferred to a transferring material and, thereafter, the residual toner on the surface of the photosensitive member is cleaned off for repetitive use, said equipment comprising means for supplying a cleaning solution and means for cleaning a photosensitive member by rubbing which is positioned between a transferring process and a charging process to effect said cleaning prior to charging, said means for supplying a cleaning solution and said means for cleaning a photosensitive member by rubbing comprising a cleaning web extending from a web supply roll to windup roll mounted adjacent said photosensitive member, a pair of spaced rollers mounted for urging said web into rubbing engagement with said photosensitive member, said web being movable in a direction opposite to the movement of said photosensitive member, an elastic cleaning solution supply roller, a transfer roller mounted for engagement with said cleaning solution supply roller and for engagement with one of said spaced rollers, a cleaning solution tank mounted under said cleaning solution supply roller, and a pump mounted in said tank, said pump having a discharge pipe for discharging cleaning solution onto said cleaning solution supply roller.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,871,081 Dated March 18, 1975 Inventor) Shozo Inoue and Akira Kurahashi It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 11, "transfused to read transferred Column 2, line 9, "1 to read l Column 5, line 29, "an" to read and Signed and sealed this let day of July 1575.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,871,081 D t d March 18, 1975 lnventofls) Shozo Inoue and Aklra Kurahashi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 11, "transfused" to read transferred Column 2, line 9, "1 to read l Column 5, line 29, "an" to read and Signed and sealed this 1st day of July 1575.