Abstract:
A filter system for removing air borne contaminants such as carbon black discharged from high speed printers such as page printers, laser printers, and the like.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation-in-part of application Ser. No. 443,122, filed Nov. 19, 1982, now abandoned, for Exhaust System for Paper Handling Machines. 
    
    
     BACKGROUND OF THE INVENTION 
     Laser and other such high speed printers have produced a problem unlike any similar printing machine because of the massive volume of paper that is processed through the printer as well as the high speed printing techniques employed. 
     One of the reasons is that carbon black, a dry product used in such printers, has unique properties that make it extremely difficult to remove either from the air or any surface to which it sticks. In addition, it has properties that make it very destructive toward other sensitive computer equipment in the computer room. 
     As is well known, computer rooms generally have a controlled temperature and humidity, and employ air conditioning equipment within the room rather than a central air conditioning unit for delivering outside air into the room. Room air conditioners are not suitable for removing carbon black from the air because this material plugs up the air conditioning and defeats its air conditioning function. 
     Removing the printer from the computer room does not solve the problem of removing contaminants from the air in the vicinity of the printer. 
     In addition, the airborne materials provide a serious health problem for the personnel operating the printing equipment. Toner chemicals and developer are discharged into the air around the high speed equipment which have been identified as being potentially harmful and health-impairing when inhaled over long periods of time, while carbon black is discharged from other printers in sufficient quantities to pose a health problem. 
     SUMMARY OF THE INVENTION 
     The prupose of the present invention is to remove and detoxify airborne particulate and chemical fumes discharged from high speed printers in a computer room having conditioned air without interfering with the normal air flow through the printer. The preferred filter apparatus removes carbon black and other contaminants from the discharge outlet of a laser printer, employing a plurality of mechanical screening devices of differing materials, some of which are rechargeable to provide longer equipment life, while at the same time eliminating a number of potentially serious health problems. 
     Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description. 
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a front elevational view of a preferred embodiment of the invention in an air conditioned computer room with the front cover removed; 
     FIG. 2 shows one form of a front cover and contaminated air inlet; 
     FIG. 3 is a fragmentary view generally as seen along lines 3--3 of FIG. 2; 
     FIG. 4 illustrates a modified form of the front cover structure shown in FIG. 2; 
     FIG. 5 illustrates still another modified form of the invention; 
     FIG. 6 shows another modified form of the invention; and 
     FIG. 7 shows the invention with a multi-inlet cover. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 of the drawings illustrate filter device 10 in an air conditioned computer room, with the hood removed. This exposes the internal components mounted in rectangular housing 12. Top cover 14 has a clean air outlet opening 16. 
     The front portion of housing 12 has a rectangular flanged lower opening 18 and a bottom 22 on which wheels 24 are mounted to make the structure mobile. Wheels 24 are pivotal, thus making the filter device 10 unidirectional. The central section of housing 12 has screening pack assembly 30, removably supported within the housing by left positioning means 26 and right positioning means 28. 
     Screening pack assembly 30 comprises four screening members. A coarse fiberglass screen pack 32 is positioned at the bottom and is designed to remove particulate up to the 10 micron range. A second and more dense fiber glass or similar material screen 34 is positioned adjacent to screen 32. The second screen is designed to remove particulate up to the 3 to 5 micron size. A third screen 36 is made up with carbonized and activated charcoal, which functions to remove odors and also to detoxify any other materials passing therethrough. A fourth screening member 38 is made from synthetic purafil and functions to also remove odors, and particulate in the 0.01 micron size range. 
     Electronically powered fan 42 is positioned immediately above screen pack 30 to draw air upwardly through the screening members to remove the carbon black and paper dust. The filtered air is discharged through opening 16. 
     FIG. 2 illustrates removable hood 50. Hood 50 has a generally rectangular configuration and is slightly larger than flanged opening 18 in housing 12. Suitable means for attachment of the hood to the housing might include any type fastener such as screws. The hood may be suspended by means of flanged members extending from housing member 12, which cooperate with key-hole slots in cover 52, or such other means which will do the job. 
     FIG. 3 illustrates housing 12 with the right edge broken away. Hood 50 has air inlet 54 mounted closely adjacent but spaced with respect to discharge opening 55A of laser printer 55B. The air flow path 56 is determined by the hood configuration. Switch 57 is mounted on the side of the housing for operating fan 42, along with a fan speed control 59. 
     FIG. 4 illustrates a modified form of hood 150 which has an extension of the duct work attached thereto to provide an additional air intake opening 154, with a baffle member 164 disposed therein for improved air intake control. The ductwork extension is designed to be positioned adjacent to an exhaust outlet from a high speed printer. Air inlet 154 is substantially the same as the structure described in connection with FIGS. 2 and 3, respectively. 
     FIG. 5 illustrates a modified form of the invention, wherein high speed laser printer 200 discharges contaminated air through opening 210 into overhead hood 74 connected by duct 76 to air inlet 54 in the filter device 10. Printer 200 could also be either a burster or a decollator. 
     In FIG. 6, a similar type structure is shown, wherein filter device 10 is ceiling mounted. An overhead hood 174 is attached to air inlet 54 in filter device 10 which receives the contaminated air being discharged from opening 210 of high speed printer 200. A hinged door 180 in the side of housing 12 permits access to the screening members for recharging, service or replacement. 
     Referring to FIG. 7, a plan view of filter device 10 is illustrated with hood 300 having a pair of lateral ducts 302 and 304 extending in different directions from hood 306. Duct 302 has an inlet opening 308 for receiving the air discharged from an laser printer discharge duct 310 while duct 304 has an opening 312 for receiving the air discharged from the outlet opening of a second laser printer 314. The air from both printers 310 and 314 are received into filter device 10 and then filtered and discharged through outlet opening 16. The embodiment of FIG. 7 is particularly useful for two or more laser printers. The two receiving ducts can be disposed at any appropriate angle or height depending upon the location of the outlet openings of the printers. 
     From the foregoing description, it is apparent that the proposed invention provides a solution for a problem confronting the high speed printing industry, in a unique and efficient manner.