Abstract: Apparatus and method for developing electrographically formed electrostatic images. Background development and "flaming" are minimized by applying composite D.C. and A.C. signals to a development electrode in a magnetic brush. The DC signal level is selected to minimize background development and the AC signal is chosen to minimize flaming.

Abstract: A nozzle for applying an air-curable adhesive to sheets of paper normally is located in a storage position with the end of the nozzle inserted into a liquid in a sump. This prevents adhesive material in the end of the nozzle from drying out or caking and thereby clogging the end of the nozzle. When the nozzle is to be used for applying adhesive, the nozzle is lifted out of the sump, the sump is moved, and the nozzle is then moved into an operating position for applying the adhesive. Also disclosed is apparatus for automatically returning the nozzle to its storage position with the end of the nozzle in the sump at the end of a cycle of operation, or when normal operation stops because of a power failure, for example.

Abstract: A duplicator has a movable photoconductor on which electrostatic images are formed. A rotatable transparent cylinder positioned adjacent the front side of the photoconductor has a screen pattern thereon. Wheels on the cylinder contact the photoconductor so that the cylinder is rotated in response to movement of the photoconductor. An elongate light shield positioned inside the cylinder has a first slot adjacent the portion of the cylinder near the photoconductor, and a Fresnel lens is positioned in the slot. Light rays from a point source located outside the cylinder pass through a second slot in the shield and are reflected from a mirror inside the cylinder onto the Fresnel lens. The lens collimates the light rays and directs them through the screen on the transparent drum to thereby project onto the photoconductor an image of the screen pattern on the cylinder.

Abstract: A set of sheets delivered seriatim from a copier/duplicator or other source are advanced along a sheet path leading from an input station to an assembly station where a booklet is formed. As a sheet is moved along the path a line of adhesive is applied to one surface of the sheet adjacent to one side edge of the sheet. In the assembly station the sheets are jogged to align the sheets of the set and then pressure is applied to the sheets over the line of adhesive. When the entire set has been bound together into a booklet, the booklet is removed from the assembly station and delivered to an output station, such as a tote tray.

Abstract: In copier/duplicators lamps provide high intensity illumination of a document at an exposure station, and an image of the illuminated document is processed and transferred to a copy sheet. The copier/duplicator can have a combination recirculating document feeder and document positioner located at a first position over the exposure station for delivery to the station of a document sheet to be copied. The feeder can be mounted for movement to a second position spaced from the exposure station so that books or other documents can be manually placed directly on the exposure station. When the feeder is in its second position it is desirable to shield the machine operator from such high intensity illumination. For this purpose, an auxiliary cover is movable between a storage position adjacent the exposure station and a second position over the exposure station.

Abstract: An adhesive applicator for applying an air-curable adhesive to sheets of paper has a nozzle that normally is located in a storage position with the end of the nozzle inserted into a liquid in a sump. This prevents adhesive material in the end of the nozzle from drying out or caking and thereby clogging the end of the nozzle. When the nozzle is to be used for applying adhesive, the nozzle is lifted out of the sump, the sump is pivoted away from the nozzle, and the nozzle is then moved into an operating position for applying the adhesive.

Abstract: A duplicator has a photoconductor on which electrostatic images are formed. A member having a screen pattern of opaque and transparent areas is positioned adjacent to the photoconductor. A Fresnel lens near the screen member receives light rays from a concentrated light source spaced from the lens. Means are provided for folding light rays from the source a plurality of times and then directing the light rays onto the lens, thereby to provide collimated light rays that are directed onto the member to provide an image of the screen pattern onto the photoconductor. The light rays can be folded by means of a polygon of glass or other suitable materials, or by two parallel mirrors and a plurality of baffles arranged so that the light rays are reflected repeatedly from one mirror surface to the other.

Abstract: An electrographic development station is disclosed which includes three magnetic brushes which sequentially apply toner to an electrostatic image on a moving photoconductor. The two upstream brushes rotate counter-current with respect to the movement of the photoconductor and have magnetic fields which overlap so that developer is carried from one brush to the other. The third magnetic brush rotates co-current with regard to such photoconductor movement. The two counter-current brushes apply a large quantity of toner to an electrostatic image on the photoconductor and the co-current brush applies a sufficient amount of toner to develop any incompletely developed portions of an electrostatic image.

Abstract: A document feeder defines a sheet path along which a document sheet is fed across a platen of a copier/duplicator, for example, in order to copy the sheet. An oscillating vacuum tube feeds sheets from a supply into the sheet path. The feeder includes a platen vacuum transport having vacuum belts that move the sheet across the platen. The vacuum transport has a first vacuum plenum and a second vacuum plenum located along the sheet path. The first vacuum plenum has a relatively high level of vacuum to insure lifting of the sheet onto the vacuum belts. The sheet is then transported into the area where it comes under the influence of the second vacuum plenum. The second vacuum plenum has a somewhat lower level of vacuum, but it is sufficient to retain the sheet on the belts as the belts drive the sheet into engagement with a registration member. The lower level of vacuum applied at the time the sheet engages the registration member voids damage to the leading edge of the sheet.

Abstract: An adhesive applicator has a nozzle through which adhesive can be dispensed to sheets of a set as the sheets are driven seriatim past the nozzle. Adhesive is furnished in a cartridge which is pressurized so that the adhesive is delivered from the cartridge to the nozzle under pressure. A valve controls the flow of adhesive from the nozzle, and the valve is under control of a logic and control unit. The logic and control unit receives signals from various sensors or detectors indicating, inter alia, the presence of an adhesive cartridge, the level of adhesive in the cartridge, the flow of adhesive from the nozzle, and the amount of adhesive in a collection bottle which receives surplus adhesive dispensed from the nozzle but not applied onto a sheet. The logic and control unit is capable of operating the valve that controls flow of adhesive from the nozzle so that adhesive is selectively dispensed from the nozzle to all but one sheet of a set of sheets.

Abstract: Copy sheets having a re-fusable xerographic toner along an edge thereof are bound into booklets by arranging the sheets in a stack and re-fusing the toner so that the re-fused toner adheres adjacent sheets together. The re-fusing operation can be accomplished after each group of a few sheets is received from a copier so that the finisher operation can be carried on at the same rate copies are produced by the copier. Alternately, a larger stack of sheets can be bound together in an off-line basis by a simple heating step.

Abstract: A document feeder defines a sheet path along which a document sheet is fed across a platen of a copier/duplicator, for example, in order to copy the sheet. An oscillating vacuum tube feeds sheets from a supply into the sheet path. The feeder includes a platen vacuum transport having vacuum belts that move the sheet across the platen. The vacuum transport has a first vacuum plenum and a second vacuum plenum located along the sheet path. The first vacuum plenum has a relatively high level of vacuum to insure lifting of the sheet onto the vacuum belts. The sheet is then transported into the area where it comes under the influence of the second vacuum plenum. The second vacuum plenum has a somewhat lower level of vacuum, but it is sufficient to retain the sheet on the belts as the belts drive the sheet into engagement with a registration member. One vacuum blower is used to establish a vacuum in the vacuum tube and in the two plenums.

Abstract: Document feeding apparatus feeds document sheets to an exposure position along a recirculating sheet path or along a non-recirculating sheet path. The feeding means has a vacuum belt for moving a sheet traveling along either sheet path past the exposure position. A document sheet can be fed to the belt for advancement to the exposure position through a slot located in a generally vertically disposed orientation and having an opening at the lower end thereof adjacent to the belt. Preferably, registration means are provided adjacent the belt at the lower end of the slot for preregistering the lower edge of a document sheet being fed through the slot to the belt. Rollers are provided for urging the document sheet against the belt, both when sheets are fed to the belt in a non-recirculating (document positioner) mode and when sheets are fed in the recirculating feeder mode of operation.

Abstract: Document sheets are removed seriatim from the bottom of a stack of sheets by an oscillating vacuum feeder having a plurality of spaced tube sections. The feeder delivers a removed sheet to a sheet transport mechanism, which transports it to the platen for copying and then removes the sheet from the platen. The sheet transport mechanism has at least one vacuum belt that passes between two adjacent sections of the feeder and picks up a sheet as it leaves the feeder so that the sheet is tacked to the feeder or the vacuum belt throughout its path of travel from the stack of sheets to the platen. After the sheet is removed from the platen it is returned to the stack of sheets on top of other sheets in the stack. A sheet inverter can be provided for inverting duplex document sheets so that both sides of such sheets can be copied. Sheets also can be fed to the platen along a non-recirculating path by a document positioner apparatus.

Abstract: Copy sheets having a re-fusable xerographic toner along an edge thereof are bound into booklets by arranging the sheets in a stack and re-fusing the toner so that the re-fused toner adheres adjacent sheets together. The re-fusing operation can be accomplished by a heating shoe and a patterned heating bar after each group of a few sheets is received from a copier so that the finisher operation can be carried on at the same rate copies are produced by the copier. Alternately, a larger stack of sheets can be bound together in an off-line basis by a simple heating step.

Abstract: A document drum and a transparent drum are mounted on a common shaft. The two drums are coaxial with each other and with the shaft. An optical system is provided for forming an image of a slit-like rectangular area of a document mounted on the external surface of the document drum onto a similar slit-like imaging area on the imaging drum. The optical system comprises a first mirror for reflecting light rays from the document drum to a lens, and second and third mirrors for reflecting light rays from the lens through the transparent drum. The optical axis of the lens is tilted relative to the light paths of the first mirror and the second mirror so that the light rays can be directed around the shaft.

Abstract: Apparatus for producing sets of copies from a set of document sheets, some of which can be produced in a collating mode by means of a recirculating feeder and others cannot be produced in a collating mode. The copies that are produced in a noncollating mode are stored temporarily. Programmable means control the making of copies in a collating mode and the delivery of copies temporarily stored so that the copies arrive at a receiver or finisher in collated sets of copies with the page order of the copy sets corresponding to the page order of the document set.