Residual toner removing apparatus

Abstract

A residual toner removing apparatus which comprises a cleaner section, a dust collecting section, a filter section and a suction section contained in a housing having an opening adjacent to a known photoreceptor surface. Brush bristles of a cleaner brush cylinder in the cleaner section are adapted to be charged with the same polarity as toner particles wiped off the photoreceptor surface so as to repel the toner particles, which are subsequently fed by an air flow into the dust collecting section and attracted by dust collecting plates with opposite charge for accumulation in the dust collecting section. The toner particles still remaining in the air flow are filtered in the filter section with a coarse filter and a fine rollup filter for complete elimination.

Description

The present invention relates to a toner removing apparatus and, more particularly, to a residual toner removing apparatus for an electrostatic copying machine.

According to a conventional residual toner removing apparatus, the elimination of toner particles remaining on a photoreceptor surface after transferring a toner powder image on a copy paper sheet is carried out by wiping the resudual toner particles off the photoreceptor surface with a rotating cleaner brush after the photoreceptor is electrically neutralized by an A.C. discharger. Although the residual toner particles may be approximately completely removed from the photoreceptor surface by the above procedure alone, the toner particles adhering to the brush bristles of the cleaner brush can not be sufficiently collected by a mere suction device such as fan, the amount of toner particles adhering to the bristles gradually increasing in the course of time with reduction of cleaning effect and durability of the cleaner brush itself, resulting in a larger power consumption during operation of the apparatus.

In the conventional residual toner removing device of the above construction, a filter of filter bag type is employed which, besides being bulky and troublesome in replacing is not sufficiently efficient for perfectly filtering the small amount of toner particles contained in a cleaning air flow, resulting in a larger size of the apparatus itself.

Accordingly, an essential object of the present invention is to provide a compact residual toner removing apparatus which provides efficient removal of residual toner particles with subsequent elimination of the disadvantages inherent in the conventional residual toner removing device.

Another important object of the present invention is to provide the residual toner removing apparatus of the above described type wherein brush bristles of a cleaner brush are electrically charged with the same polarity as the toner particles for easy removal of the toner particles from the brush bristles.

A further object of the present invention is to provide the residual toner removing apparatus of the above described type wherein the collection of removed toner particles are easily effected by the provision of a removable cover plate having dust collecting plates electrically charged with opposite polarity to the toner particles, and a buffer plate for an air flow containing toner particles.

A still further object of the present invention is to provide the residual toner removing apparatus of the above described type wherein the toner particles contained in the air flow are completely filtered at a coarse filter and a fine filter without clogging the filters and variation in the rate of air flow.

According to the preferred embodiments of the present invention, the residual toner removing apparatus comprises a cleaner section, a dust collecting section, a filter section and a suction section contained in a housing having an opening adjacent to a known photoreceptor surface driven by a conventional means. In the cleaner section close to the photoreceptor surface, a cleaner brush cylinder with brush bristles secured to the surface thereof is adapted to rotate between an upper casing plate and a lower casing electrically insulated from each other, the brush bristles rubbing during rotation against the middle portion of the upper casing, thus being charged with the same positive polarity as toner particles, so that the toner particles wiped off the photoreceptor surface by the brush bristles are electrically repelled from the bristles and fed into subsequent sections by an air flow through a space between the tips of the bristles and the lower casing for complete elimination of residual toner particles from the photoreceptor surface and the cleaner brush.

Furthermore, the above upper casing plate with negative charge is electrically connected to a pair of dust collecting plates in the dust collecting section for positively attracting the removed toner particles thereto. The subsequent filter section comprises a coarse filter, and a fine rollup filter with filter screen successively displaceable by winding, thus resulting in small size of the whole apparatus with uniform air flow and suction force by the suction section for perfect elimination of residual toner particles.

These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which;

FIG. 1 is a schematic diagram showing a sectional side view of a residual toner removing apparatus according to the present invention,

FIG. 2 is a schematic diagram showing a perspective view of a filter section of the above residual toner removing apparatus, and

FIG. 3 is a cross sectional view taken along the line II--II in FIG. 1.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like numerals throughout the views of the accompanying drawings.

Referring to FIG. 1, the residual toner removing apparatus which extends the width of a known electrophotosensitive photoreceptor 1 of an electrostatic copying machine generally comprises 4 sections, i.e., a cleaner section A, a dust collecting section B, a filter section C and suction section D contained in a housing T of rectangular prism shape having an elongated opening Ta extending the width of the photoreceptor 1 adjacent to the surface thereof. The photoreceptor 1 is of a known construction and driven by a conventional means.

In the cleaner section A, the bottom of the housing T close to the opening Ta is formed into a concave lower casing 5 in the form of a trough, over which a cleaner brush cylinder 2 with brush bristles 3 of animal fur such as rabbit fur or synthetic fur secured to the surface thereof is rotatably provided by suitable means. A convex upper casing plate 4 fixedly provided above the brush cylinder 2 is electrically insulated from the lower casing 5, and divides the cleaner section A into two portions, A' for the cylinder 2 and 7 for air passage. The tips of the brush bristles 3 are adapted to rub against the inner surface of the upper casing plate 4 of the middle part 4a thereof, keeping a fixed distance 6 to the inner surface of the lower casing 5 during rotation, while applying very light pressure to the photoreceptor surface 1. The upper casing 4 which extends the width of the housing T is made of brass, being adapted to be charged negative when rubbed by the tips of brush bristles 3 during rotation of the cylinder 2, while the brush bristles 3 are charged positive, i.e., the same polarity as the toner powder.

The dust collecting section B further comprises a removable rectangular cover plate 9 which fits a rectangular opening Tb formed in the bottom of the housing T and extends the width of the housing T, two dust collecting plates 10 and 10' removably fixed on the cover plate 9 at right angles thereto in spaced relation to each other, projecting approximately half way into the housing T, and a buffer plate 11 fixed at right angles to the inner surface of the housing T at the upper part thereof and projecting half way into the housing T between the plates 10 and 10', the dust collecting plates 10 and 10' and the buffer plate 11 extending the width of the housing T forming a passage 12 for air flow containing toner particles. The plates 10 and 10' are electrically connected to the upper casing 4 with negative charge in the cleaner section A. Accordingly, the residual toner particles with positive charge wiped off the surface of the photoreceptor 1 by the rotation of the brush bristles 3 and contained in the flow of air caused by a silocco fan 17 provided in the suction section D are adapted to be attracted to the surfaces of the dust collecting plates 10 and 10' with negative charge.

Referring to FIG. 2, the filter section C comprises a coarse filter 13 installed adjacent to the plate 10' with a fine rollup filter 14 provided at the back of the filter 13 in spaced relation, the rollup filter 14 being adapted to be successively wound into a case 15 by turning a winding knob 16 as in a camera. The filters 13 and 14 are of such dimensions that fit the width and the height of the housing T, forming a filter partition in the housing T at the back of the plate 10'. In the suction section D at the other end of the housing T remote from the side thereof facing the photoreceptor 1, the sirocco fan 17 for suction is provided to cause the air flow through the housing T.

Referring back to FIG. 1, when the cleaner brush cylinder 2 is rotated in the opposite direction to the photoreceptor 1 as is shown by an arrow, for example, at a speed of 800 r.p.m., the brush bristles 3 on the cylinder 2 wipe residual toner particles off the surface of the photoreceptor 1, simultaneously rubbing against the brass middle part 4a of the upper casing plate 4, which is charged with a voltage between 4000 and 5000 volts in the opposite polarity to the toner particles. In the above state, since the residual toner particles and the brush bristles 3 charged with the same positive polarity repel each other, the toner particles are separated from the brush bristles 3 by the centrifugal force and the air flow caused by the above mentioned sirocco fan 17, thus being fed into the dust collecting section B through the space 6 between the bristles 3 and the lower casing 5. As the bristles 3 closely contact the middle portion 4a of the upper casing 4, the separated toner particles are not normally pushed out onto the photoreceptor 1 at the upper part between the photoreceptor 1 and the opening Ta during rotation of the brush cylinder 2. Should the toner particles come out onto the photoreceptor 1 at the upper part thereof, they are carried into the dust collecting section B by an air flow shown with an arrow through the passage 7 formed between the upper casing 4 and the top of the housing T without scattering onto the photoreceptor side.

The positively charged toner particles thus fed into the dust collecting section B are attracted by the negatively charged dust collecting plates 10 and 10' which are electrically connected to the upper casing 4 also with negative charge, and subsequently falls by gravity on the cover plate 9 for accumulation.

It should be noted here that the dust collecting plates 10 and 10' are made of electrically conducting material such as aluminum are connected to the upper casing 4 by a line L as is seen from FIG. 1 and adapted to be charged with a voltage between 4000 and 5000 volts in the opposite polarity to the toner particles similarly to the upper casing 4, while the lower casing 5 is electrically insulated from the dust collecting electrode plates 10 and 10' and also earthed through a line L'.

The provision of the baffle plate 11 between the plates 10 and 10' is effective for preventing the air flow containing the separated toner particles from being directly fed into the filter section C with sufficient attraction of the toner particles to the surfaces of the plates 10 and 10', and also for efficiently dropping the toner particles on the cover plate 9 by gravity.

Referring to FIG. 3, which shows a mechanism for removing the toner particles adhering to the surface of the dust collecting plates 10 and 10', and the baffle plate 11, a pair of guide bars 18 and 18' extending the width of the housing T are inserted into the housing T through small openings Tc and Tc' at the right side wall thereof adjacent to the tips of the plates 10 and 10' respectively. A knob 19 is rigidly fixed to the right end of the bar 18 projecting from the opening Tc while a rectangular electode cleaner plate 20 contacting the left side wall of the housing T is secured to the left end of the bar 18 inside the housing T. The cleaner plate 20 with height fitting in the height of the side walls of the housing T and length extending the length of the dust collecting section B is provided with slits corresponding to the cross sections of the dust collecting plates 10 and 10' and also the buffer plate 11, so that the plate 20 can be slidably moved along the surfaces of the plates 10 and 10', and the baffle plate 11 in close contact therewith. A band of blade 21 made of elastic material such as rubber and having the a cross section of a right-angled triangle is rigidly fixed to the surface of the cleaner plate 20 along the configuration of the slits thereon for a firm contact without rattling or the like. An outlet Td for the toner powder extending the lenght of the cleaner plate 20 is provided at the lower part of the right side wall of the housing T with a corresponding trough-shape toner tank 22 removably attached to the edges of the outlet Td. For removing the toner particles adhering to the surfaces of the plates 10 and 10', and the baffle plate 11, the knob 19 is pulled out in the direction of an arrow to the position shown in chain lines with the cleaner plate 20 and the blade 21 moving in the same direction by means of the guide bar 18, during which time the blade 21 scrapes the toner powder off the surface of the plates 10 and 10' and the baffle plate 11, simultaneously carrying the removed toner particles into the toner tank 22.

Although most of the toner particles are removed in the dust collecting section B as described above, a small quantity of the toner particles remaining in the air flow is further filtered in the subsequent filter section C.

Since the filter section C comprises the coarse filter 13 and the fine rollup filter 14, the toner particles still remaining in the air flow after passing through the coarse filter 13 are completely eliminated by the fine filter 14.

Furthermore, as the fine rollup filter 14 can be successively displaced by winding in the direction of the arrow in FIG. 2 so as to bring unexposed filter screen into the path of the incoming air, no reduction of air flow rate is caused by the clogging of the filter screen.

Although, in the above embodiment, the positively charged residual toner particles on the photoreceptor 1 are wiped off by the brush bristles 3 of the brush cylinder 2, electrically repelled from the positively charged brush bristles 3, and fed into the dust collecting section B by the air flow, provision of a flicker rod 8 at the rear of the brush cylinder 2 in the path of the brush bristles 3 for mechanically beating off negatively or neutrally charged toner particles without electrical repelling is effective for more complete elimination of the toner particles as adhesion of the toner particles to the brush bristles 3 is further prevented. In this case, the flicker rod 8 is of a conventional construction.

From the foregoing description, it has now become clear that, according to the first embodiment of the present invention, the residual toner particles adhering to the photoreceptor surface 1 are mechanically wiped off by the brush bristles 3, and the toner particles separated thereby with positive charge are electrically repelled by the positively charged brush bristles 3, simultaneously being carried away into the dust collecting section B by the air flow, thus keeping the photoreceptor surface 1 perfectly clean for a long period of time with effective collection of the separated toner.

In the second embodiment according to the present invention, in addition to the above described effect, the dust collecting plates 10 and 10' are electrically connected to the upper casing 4 for charging the plates 10 and 10' with opposite polarity to the separated toner powder as the brush bristles 3 rub against the middle portion 4a of the upper casing 4 during rotation, thus completely eliminating the toner particles contained in the air flow by electrical attraction.

Furthermore, the provision of the buffer plate 11 to divert the air flow is effective for more efficient collection of the separated toner particles by gravitation. The removable cover plate 9 having the dust collecting plates 10 and 10' removably secured thereon is convenient for easy collection of the removed toner powder.

In the third embodiment according to the present invention, the small sized filter comprising the coarse filter 13 and fine rollup filter 14 adopted instead of the conventional bulky filter of filter bag type efficiently prevents the clogging of filter screen with constant flow rate of air especially by the fine rollup filter 14 being successively displaceable by winding.

Accordingly, in the residual toner removing apparatus according to the present invention, the residual toner particles wiped off the photoreceptor surface by the brush bristles during rotation of the brush cylinder are positively fed into the subsequent sections without the toner particles being dispersed outside the apparatus and with minimum soiling of the brush bristles, thus the photoreceptor surface being thoroughly cleaned with little power consumption, which is suitable for wide industrial application.

Although the present invention has been fully described by way of example with reference to the attached drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as included therein.

Claims

What is claimed is:

1. In a residual toner removing apparatus which comprises a cleaner section, a dust collection section, and a filter section followed by a suction section, the improvements which comprise brush bristles of a cleaner brush cylinder rotatably provided in said cleaner section being adapted to rub against an upper casing plate at an approximately middle portion thereof for charging said brush bristles with the same polarity as toner particles, and said upper casing plate with opposite polarity to said brush bristles, and said cleaner brush cylinder being provided between said upper casing plate and a lower casing electrically insulated from each other with a fixed distance between tips of said brush bristles and said lower casing, said toner particles wiped off a photoreceptor surface by said brush bristles being electrically repelled from said brush bristles and simultaneously fed into a subsequent dust collecting section by an air flow produced by a suction in said suction section, and dust collecting plates provided in said dust collecting section, said dust collecting plates being electrically connected to said charged upper casing plate for attracting said toner particles to said dust collecting plates.

2. In a residual toner removing apparatus which comprises a cleaner section, a dust collecting section, and a filter section followed by a suction section, the improvements which comprise brush bristles of a cleaner brush cylinder rotatably provided in said cleaner section being adapted to rub against an upper casing plate at an approximately middle portion thereof for charging said brush bristles with same polarity as toner particles and said upper casing plate with opposite polarity to said brush bristles, and said cleaner brush cylinder being provided between said upper casing plate and a lower casing electrically insulated from each other with a fixed distance between tips of said brush bristles and said lower casing, said toner particles wiped off a photoreceptor surface by said brush bristles being electrically repelled from said brush bristles and simultaneously fed into a subsequent dust collecting section by an air flow produced by a suction in said suction section, wherein a coarse filter and a fine rollup filter with filter screen successively displaceable by winding are provided in said filter section between said dust collecting section and said suction section, said coarse filter being positioned to the side of said dust collecting section.

3. In a residual toner removing apparatus which comprises a cleaner section, a dust collecting section, and a filter section followed by a suction section, the improvements which comprise brush bristles of a cleaner brush cylinder rotatably provided in said cleaner section being adapted to rub against an upper casing plate at an approximately middle portion thereof for charging said brush bristles with same polarity as toner particles and said upper casing plate with opposite polarity to said brush bristles, for preventing the toner particles from adhering to said brush bristles and said cleaner brush cylinder being provided between said upper casing plate and a lower casing electrically insulated from each other with a fixed distance between tips of said brush bristles and said lower casing, said toner particles wiped off a photoreceptor surface by said brush bristles being electrically repelled from said brush bristles and simultaneously fed into a subsequent dust collecting section by an air flow produced by a suction in said suction section, said cleaner brush, after the brush bristles thereof rub against said upper casing, rotating in a direction to move along said lower casing with a small gap maintained between said brush bristles and said lower casing, said upper casing and an upper part of a housing of said residual toner removing apparatus defining, at edges thereof adjacent to said photoreceptor surface, an air suction inlet with said upper casing and said upper part of said housing being disposed at a predetermined distance from each other for forming an air passage therebetween, a flicker means being disposed at a side of said cleaner brush whereat said cleaner section communicates with said suction section, and in such a position that said flicker means strikes against said brush bristles as said cleaner brush rotates.

4. A residual toner removing apparatus as claimed in claim 3 wherein said flicker means is a flicker bar disposed at a central portion of an air outlet defined by the edge of said upper casing remote from said photoreceptor surface and said lower casing.

5. A residual toner removing apparatus as claimed in claim 1, further comprising a baffle plate provided between said dust collecting plates.

6. A residual toner removing apparatus as claimed in claim 1 wherein a cleaner plate having slits corresponding to cross sections of said dust collecting plates and said baffle plate is provided in said dust collecting section so as to move along surfaces of said dust collecting plates and baffle plate.

7. A residual toner removing apparatus as claimed in claim 4, wherein a blade is rigidly fixed to a surface of said cleaner plate along configuration of said slits for better contact between slits of said cleaner plate and said dust collecting plates and said baffle plate.