GB2179274A

GB2179274A - Toner apparatus

Info

Publication number: GB2179274A
Application number: GB08618272A
Authority: GB
Inventors: Harry Arthur Hele Spence-Bate; Timothy Bain-Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-07-25
Filing date: 1986-07-25
Publication date: 1987-03-04
Also published as: GB8618272D0

Abstract

In order to tone a latent image on an electronically charged film (1), a plate (3) is provided at a toning station, over which plate toner can flow and remain on by surface tension, the toner flowing from a source (8...) to an aperture (5) in the plate. In order to drain off small amounts of excess toner present a drain (13) is provided which is connected to a container (12) or groove around the plate. The use of surface tension to cover the plate enables small amounts of toner to be used so that circulation of toner can be avoided. <IMAGE>

Description

SPECIFICATION Toner apparatus The present invention relates to a method and appar atus fortoning electrically latent imaged film.

There have been various proposalsforensuring that the correct amount oftoner is positioned adjacent a latent imaged electrostatic film. For example in US Patent No. 4,122,906 M.R. Kuehnle proposed to position the film adjacent a sponge full oftonerand then squeeze the sponge to eject toner on to the film.

There have been other proposals to pump toner into a "sink" below the film and overflowthe sink so asto ensurethatthefilm placed on top of the sink is fully covered. Subsequently the overflowed toner is recirculated. Neither of these two methods iswhollysatis- factory since generally an excess of toner is produced.

Accordingly the present invention comprises toner apparatus with means to hold an electrostatically imaged film at a toner station, wherein there is provided at the toner station a plate, the plate having at least one aperture connectable to a source of toner and a drain around the plate.

By replacing the "sink" or sponge by a plate it is possible to use the plate to spread the toner by means of surface tension in very small quantities overthe area of the plate at the toner station. Large excesses oftoner can thereby be avoided. If the apparatus is further provided with an accurate metering system, for example using a peristaltic pump, it is possibleto almost eliminate tonerwastage. lnthiswaytoner recirculation is generally avoided.

The invention also comprises a method oftoning an electrostatically latently imaged film by locating the film above a plate floating toner over the plate from a central area of the plate towards the outer extremeties of the plate whereby toner on the plate is attracted to thefilmforimaging.

Four embodiments of the invention will now be described in detail by way of example with reference totheaccompanying drawings in which:- Figure 'shows in perspective a first toning apparatus according to the invention.

Figure2 shows in perspective a second toning apparatus according to the invention, Figure 3 shows in perspective a third toning apparatus according to the invention, and Figure4shows in perspective a fourth toning apparatus according to the invention.

In Figure 1 there is shown a film 1 located ata toning station generally shown at 2 above a plate 3 in which are three apertures 4,5 and 6. Connected to aperture 5 to an eventual souce 7 of toner, is a pipe 8 connected to a metering pump 9. The metering pump is shown as a piston driven pump for diagramatic purposes but is preferably an accurate metering pump using for example a peristaltic pump such as is used for administering small quantities of medications. Pump 9 is connectedtotonersupply7 and a toner liquid dispenser 10. The supply of toner liquid is adjustable so as to control the toner density.

Around plate 3 is a container 12 at the bottom of which is a drain 13.

Connectable to apertures 4 and 6 by conduits 14 and 16 are provisions for auxiliary toning liquid such as may be used with colourtoning.

In Figure 2 a similar apparatus is shown to that in figure 1 and parts are numbered the same to indicate similarfeatures which need no further description.

The main difference between the embodiments is that plate 3 is surrounded by a drain channel 20 rather than the container or shroud 12 of Figure 1. Drain conduits 13 connect in this embodiment to the bottom of channel 20. Isopar paraffin is used as a toner liquid in reservoir 10.

In orderto image film 1 which has already been latently imaged electrostatically, the metering pump 9 provides a small amountoftoner in liquid suspension at aperture 5 which then separates out over plate 3 until plate3 is covered. The film is held atatoner station on a suitable holding device such as a vacuum platen a small distance away from plate 3 and the toner in suspension rapidly transfers to the film. Due to the small amount oftoner used and the reliance on surface tension to separate and hold the toner in the plate area, it is possible to orientate the plate in positions other than horizontal. The arrangement may be madeto work even in a vertical or upside down orientation.

In the third embodiment provision is made to drain away excess toner before spreading overthe plate 3.

Thus an elongate slot is provided on the surface of plate 3 at the extremeties of which are apertures 4 and 6. These apertures may be connected in one position by means of valves 24,26 of a slide valve member 25 controlled by solenoid 27 to auxiliary conduits 14 and 16 as in Figures 1 and 2 or else in another position of the solenoid, which rotates valve member 32, the apertures4and 6are both connectedthrough con- duits28 and valve member'T' duct31 to drain 30. In this embodiment it is thus possible to continuously circulate toner to prevent toner grain separation from the carrier liquid in conduit8when the apparatus is not being used.A peristaltic pump 15 is conveniently used to meterthe correct amounts oftoner and an agitator 11 is used to continually stir the contents of mixing chamber9'.

A slightly different arrangement is provided in the fourth embodiment where the toner can again be recirculated but without flowing onto the surface of plate 3. This is enabled by providing a cylindrical rotatable valve 40 which is rotated by shaft 48. Toner can either pass up conduit 8, through port47,valve conduit 41 to aperture 42, level with plate 3 or else in the other position of valve 40, through ports 47,44 'U' shaped conduit 49, ports 46,45 and thence down drain 43.

Although circulation or continuous flow is provided conveniently by embodiments 3 and 4 both arrangements are particularly designed to prevent excess flows. By suitable valve control the flow can be made intermittent but sufficient to prevent separation of toner.

1. Toner apparatus having meanstoholdanelec- trostatically imaged film at a toner station, is provided

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Toner apparatus The present invention relates to a method and appar atus fortoning electrically latent imaged film. There have been various proposalsforensuring that the correct amount oftoner is positioned adjacent a latent imaged electrostatic film. For example in US Patent No. 4,122,906 M.R. Kuehnle proposed to position the film adjacent a sponge full oftonerand then squeeze the sponge to eject toner on to the film. There have been other proposals to pump toner into a "sink" below the film and overflowthe sink so asto ensurethatthefilm placed on top of the sink is fully covered. Subsequently the overflowed toner is recirculated. Neither of these two methods iswhollysatis- factory since generally an excess of toner is produced. Accordingly the present invention comprises toner apparatus with means to hold an electrostatically imaged film at a toner station, wherein there is provided at the toner station a plate, the plate having at least one aperture connectable to a source of toner and a drain around the plate. By replacing the "sink" or sponge by a plate it is possible to use the plate to spread the toner by means of surface tension in very small quantities overthe area of the plate at the toner station. Large excesses oftoner can thereby be avoided. If the apparatus is further provided with an accurate metering system, for example using a peristaltic pump, it is possibleto almost eliminate tonerwastage. lnthiswaytoner recirculation is generally avoided. The invention also comprises a method oftoning an electrostatically latently imaged film by locating the film above a plate floating toner over the plate from a central area of the plate towards the outer extremeties of the plate whereby toner on the plate is attracted to thefilmforimaging. Four embodiments of the invention will now be described in detail by way of example with reference totheaccompanying drawings in which:- Figure 'shows in perspective a first toning apparatus according to the invention. Figure2 shows in perspective a second toning apparatus according to the invention, Figure 3 shows in perspective a third toning apparatus according to the invention, and Figure4shows in perspective a fourth toning apparatus according to the invention. In Figure 1 there is shown a film 1 located ata toning station generally shown at 2 above a plate 3 in which are three apertures 4,5 and 6. Connected to aperture 5 to an eventual souce 7 of toner, is a pipe 8 connected to a metering pump 9. The metering pump is shown as a piston driven pump for diagramatic purposes but is preferably an accurate metering pump using for example a peristaltic pump such as is used for administering small quantities of medications. Pump 9 is connectedtotonersupply7 and a toner liquid dispenser 10. The supply of toner liquid is adjustable so as to control the toner density. Around plate 3 is a container 12 at the bottom of which is a drain 13. Connectable to apertures 4 and 6 by conduits 14 and 16 are provisions for auxiliary toning liquid such as may be used with colourtoning. In Figure 2 a similar apparatus is shown to that in figure 1 and parts are numbered the same to indicate similarfeatures which need no further description. The main difference between the embodiments is that plate 3 is surrounded by a drain channel 20 rather than the container or shroud 12 of Figure 1. Drain conduits 13 connect in this embodiment to the bottom of channel 20. Isopar paraffin is used as a toner liquid in reservoir 10. In orderto image film 1 which has already been latently imaged electrostatically, the metering pump 9 provides a small amountoftoner in liquid suspension at aperture 5 which then separates out over plate 3 until plate3 is covered. The film is held atatoner station on a suitable holding device such as a vacuum platen a small distance away from plate 3 and the toner in suspension rapidly transfers to the film. Due to the small amount oftoner used and the reliance on surface tension to separate and hold the toner in the plate area, it is possible to orientate the plate in positions other than horizontal. The arrangement may be madeto work even in a vertical or upside down orientation. In the third embodiment provision is made to drain away excess toner before spreading overthe plate 3. Thus an elongate slot is provided on the surface of plate 3 at the extremeties of which are apertures 4 and 6. These apertures may be connected in one position by means of valves 24,26 of a slide valve member 25 controlled by solenoid 27 to auxiliary conduits 14 and 16 as in Figures 1 and 2 or else in another position of the solenoid, which rotates valve member 32, the apertures4and 6are both connectedthrough con- duits28 and valve member'T' duct31 to drain 30. In this embodiment it is thus possible to continuously circulate toner to prevent toner grain separation from the carrier liquid in conduit8when the apparatus is not being used.A peristaltic pump 15 is conveniently used to meterthe correct amounts oftoner and an agitator 11 is used to continually stir the contents of mixing chamber9'. A slightly different arrangement is provided in the fourth embodiment where the toner can again be recirculated but without flowing onto the surface of plate 3. This is enabled by providing a cylindrical rotatable valve 40 which is rotated by shaft 48. Toner can either pass up conduit 8, through port47,valve conduit 41 to aperture 42, level with plate 3 or else in the other position of valve 40, through ports 47,44 'U' shaped conduit 49, ports 46,45 and thence down drain 43. Although circulation or continuous flow is provided conveniently by embodiments 3 and 4 both arrangements are particularly designed to prevent excess flows. By suitable valve control the flow can be made intermittent but sufficient to prevent separation of toner. CLAIMS

1. Toner apparatus having meanstoholdanelec- trostatically imaged film at a toner station, is provided atthe toner station with a plate, the plate having at least on its film facing surface one aperture connectable to a source of toner and a drain around the plate.

2. Apparatus as claimed in claim 1 wherein at least one further aperture connectable to a further tonersource is provided on its film facing surface.

3. Apparatus as claimed in claim 1 or 2 wherein a groove is provided around the plate to drain the plate.

4. Apparatus as claimed in claim 1 or2wherein the plate is provided within a shroud with a gap between the plate and shroud to drain the plate.

5. Apparatus as claimed in any one of claims 1 to 4 wherein the aperture or apertures are provided within an elongate groove in the plate surface.

6. Apparatus as claimed in claim 2 wherein the further aperture or apertures is/are connectable by a valve to a drain.

7. Apparatus as claimed in claim 1 wherein a conduit between aperture and tonersource is connectable by a valveto drain.

8. Apparatus as claimed in claim 7 wherein the valve is a rotatable member having a surface substantiallyflush with the surface ofthe plate, the aperture being in thatvalve surface.

9. Toner apparatus substantially as described with reference to any one of Figures 1 to 4.