Filter for removing smoke and toner dust in electrophotographic/electrostatic recording apparatus
AssigneeFujitsu Limited
InventorYoshihiro Tonomoto
Life of this patent
Estimating the term…
Abstract
An air filter structure is described including a plurality of filter units, wherein a first filter unit made of electrostatically charged fibrous material is utilized at the inlet side of the air filter. The first filter unit has a comparatively greater porosity than the remaining filter units and attracts and removes toner particles charged with an opposite polarity to that of electrostatically charged fibrous material in the first filter unit. Therefore, the air, with a substantial part of toner dust removed, can more easily enter into the remaining filter units for removal of smoke, resulting in increased useful life of the air filter.
Claims11
An air filter for removing smoke and toner dust particles from air, the toner dust particles being both large and fine, having a predetermined average toner particle size of about 10 microns, and having a positive polarity, said air filter having an air inlet side and an air outlet side and comprising;
- (a) a first filter unit disposed at the air inlet side of said air filter;
- and
- (b) at least a second filter unit disposed between said first filter unit and said air outlet side,
- wherein said first filter unit includes --negatively electrostatically charged fibrous material for attracting the positively charged toner particles, said charged fibrous material being made of a fibrous dielectric material and a solution coating of vinylidene fluoride and methyl ethyl ketone coated onto said fibrous dielectric material, and a first predetermined porosity greater than about 10 microns--for removing a substantial part of the large toner dust particles from the air and for allowing the fine toner dust particles and smoke to pass therethrough;
- and
- wherein said second filter unit includes fibrous material without an electrostatic charge, said uncharged fibrous material having a second predetermined porosity less than about 10 microns for removing the fine toner dust particles and smoke.
An air filter for removing smoke and toner dust particles from air, the toner dust particles being both large and fine, having a predetermined average toner particle size of about 10 microns, and having a negative polarity, said air filter having an air inlet side and an air outlet side and comprising:
- (a) a first filter unit disposed at the air inlet side of said air filter;
- and
- (b) at least a second filter unit disposed between said first filter unit and said air outlet side,
- wherein said first filter unit includes--positively electrostatically charged fibrous material for attracting the negatively charged toner particles, said charged fibrous material being made of a fibrous dielectric material and a solution coating of styrene acrylic and methyl ethyl ketone coated onto said fibrous dielectric material, and a first predetermined porosity greater than about 10 microns--for removing a substantial part of the large toner dust particles from the air and for allowing the fine toner dust particles and smoke to pass therethrough, and
- wherein said second filter unit includes fibrous material without an electrostatic charge, said uncharged fibrous material having a second predetermined porosity less than about 10 microns for removing the fine toner dust particles and smoke.
Dependencies are inferred from the claim text.