Abstract: A feeder for separating sheet form elements, such as envelopes, from a stack has a suction device and a mechanical gripper mounted together on a movable head. The movement of the head is controlled by a lever mechanism and cams so that an envelope is first pulled by the suction in the stacking direction and then gripped and pulled laterally from the stack by the gripper.

Abstract: A label pickup mechanism for an in-mold blow molding machine has a rotating magazine system which allows the captive stack of labels to rotate about a center point by sliding on a circular track of a radius common to the base plate of the label magazine and a front plate carried in the label support apparatus. Such rotation prevents the label stack to lose its coordinate position while trying to address label askewness. The label stack is kept compressed against retaining tabs by using label pushers.

Abstract: For the initial operation or changeover of a can body welding machine, a modular stack magazine to guide and hold a stack of blanks has adjustable stack supports with holding surfaces projecting under the lowermost blank. These stack supports are adjustably mounted on a frame which is releasably connected to a blank separating device. To assist the destacking of individual blanks, adjustable spreading air feed elements are also fitted to the frame. These adjustable components together with the frame form an exchangeable module, so that once their settings have been carried out--the setting operations being inherently complex, because as they are governed by many other parameters besides size of blank they have to be arrived at empirically, and they must be made all over again if just one of those parameters is altered--the module can be stored ready for reuse after maintenance operations, or after the use of another module.

Abstract: A sheet feeding apparatus with a sheet supporting unit for supporting sheets, a sheet absorb device for air-absorbing a lowermost sheet from among the sheets supported by the sheet supporting unit, a conveyer for conveying the sheet absorbed to the sheet absorb device, a regulator for regulating a downward movement of the sheets supported by the sheet supporting unit by abutting tip ends of such sheets against the regulator, a passage arranged between the conveyer and the regulator and adapted to guide the sheet conveyed by the conveyer, and a controller for driving the conveyer in a reverse direction after the sheet conveyed by the conveyer is fed out through the passage.

Abstract: A vacuum corrugation feeder used to feed a wide variety of sheet sizes and stocks includes a variable ratio feedhead plenum. Included within vacuum plenum is an adjustable shutter apparatus that includes a foam roller mounted for rotation on shaft. A shutter member in the form of a plastic sheet is connected to the foam roller and can be wrapped and unwrapped around the foam roller by rotation of knob that is connected to the shaft depending on whether the vacuum pressure is to be high or low. The foam roller is mounted above a plenum plate of the vacuum plenum such that rotation of the knob in a clockwise direction causes the shutter to unwrap from the foam roller and partially cover vacuum holes in the plenum plate and thereby decrease the amount of negative pressure from the vacuum plenum that reaches sheets being fed.

Abstract: Method for controlling a valve unit having a rotatable inner part, by which at least one of positive pressure and negative-pressure consumers of a sheet-processing machine is connectible to and disconnectible from a source of positive pressure and negative pressure, respectively, in accordance with an operating cycle of the sheet-processing machine, the operating cycle being repeated at a frequency variable between a minimum cycle frequency and a maximum cycle frequency, includes superimposing an adjusting speed on a rotary speed of the rotatable inner part of the valve unit; and device for performing the method.

Abstract: A sheet feeding apparatus to control the injection quantity of air to a document bundle and to allow a stable supply of paper regardless of the document size, document quantity or curling of the document. In the case where air is blown by a separation air injection unit against the front edge of a document loading unit, document-floating sensors are provided protruding upward from a sheet feeding belt. The floating sensors can be for example contact-type sensors such as microswitches to set that injection amount of air to an optimum injection amount of air when the state of the floating sensors, changes compared to their initial state.

Abstract: A stack of sheets or blanks for feeding one by one from the bottom of the stack by a feeding mechanism is supported for high speed feeding to subsequent stations. A feed cylinder rotatably supported beneath the leading edge of the stack includes a suction device. An intermediate portion of the blank leading edge is drawn by the suction device downwardly toward an opening in the periphery of the feed cylinder. Continued rotation of the feed cylinder further bends the blank. For blanks of large size and having a leading edge with an irregular contour the blank leading edge intermediate portion extends forwardly from edge lateral portions. Positioned in spaced relation along the interior of the feed cylinder are a plurality of air manifolds having outlets directed at selected angles upon the lateral portions of the blank leading edge. The manifolds are connected to a source of pressurized air which is directed in a sweeping motion upon the blank leading edge lateral portions upon rotation of the feed cylinder.

Abstract: A device for transporting material, in the form of discrete sheets, seriatim to a stack of discrete sheets, and subsequently seriatim away from such stack. The discrete sheet material transport device comprises a support for a stack of discrete sheets. The stack support includes a first stop for a first marginal edge of a discrete sheet, and opposed second and third stops for opposed marginal edges of a discrete sheet perpendicular to the first marginal edge of such discrete sheet. Discrete sheets are delivered seriatim to the vicinity of the stack support and are urged in a first direction into engagement with the first stop to form a stack of discrete sheets on the stack support. The discrete sheets are subsequently urged seriatim in a direction opposite the first direction to remove discrete sheets seriatim from the stack on the stack support. The second and third stops are located to accurately position the stack of discrete sheets on the stack support.

Abstract: A device whereby sheets can be discharged one by one from the bottom of a stack of sheets provided in a holder having a base support and side supports wherein in the transverse direction of sheet transport the base support surface has a downward bent shape so that the support surface has a deepened part on its supporting side such that in the proximity of the deepened part, beneath at least an edge zone of one side of a stack of sheets to be accommodated, the support surface is provided with at least one opening in which a vacuum can be created so that the bottom sheet is sucked against the support and air is blown against the side of the stack as considered with respect to the direction of sheet transport, in order to create an air layer at least between the bottom sheet and the stack thereabove, the airflow being ejected in the proximity of the deepened part of the support surface.

Abstract: Device for facilitating sheet separation or singling in an upper region of a feeder pile, wherein equipment for acting upon an edge of the feeder pile facing away from a processing machine is adjustably movable against lateral edges of the sheet pile, includes a supporting structure disposed above a feeder pile and extending beyond dimensions of a maximally processable format of a printing material and being swivellable out of a plane extending parallel to a top surface of the feeder pile, and elements for facilitating sheet separation carried by said supporting structure.

Abstract: An automatic sheet printing and alignment system includes a holding table; a transport system for moving the table through a plurality of stations; a first station for positioning a sheet on the table; a second station for printing features on the sheet positioned on the table; a third station for receiving the printed sheet from its position on the table to compile a stack of sheets with their printed features in predetermined alignment; and a control system for sequentially moving the table through the stations for repeatedly printing and stacking each sheet aligned with prior printed and stacked sheets received, transported and printed by the same table.

Abstract: The collating machine comprises a frame (10), a plurality of superposed trays (20) in the frame in order to be loaded with stacks of paper (28), each tray (20) being fitted with an individual sheet ejection device and a transfer device, and a vertical conveyor (26) adjacent to the transfer devices of the trays (20) to receive, by the intermediary of the transfer devices, sheets ejected from their trays and to move the same to a collating station. The ejection device comprises several endless perforated tapes (34) carried on two spaced bend rolls (36 and 38) and a vacuum chamber (46) surrounded by the tapes (34) and having apertures, for the passage of air, distributed in its lower wall which is adjacent to the internal surface of the lower run (34a) of the tape (34).

Abstract: A printing press for printing an image on sheets of printing stock can generally have a sheet feeder for separating and at least initiating start of transport of the separated sheet into the printing press. Such a sheet feeder can have a device for controlling feeder blowing air and feeder suction air, wherein the control device can have respective valves for accurately controlling the amount of blowing air and suction air. In addition, the amount of blowing air can be essentially exactly adjustable via the control console of the machine.

Abstract: A device for separating flat parcels from a stack of parcels includes a drawing element that travels in a conveying direction and acts by friction on a parcel to be drawn off from the stack of parcels. A guide wall for the stacked parcels forms a gap with the drawing element for a drawn off parcel to pass through. A support surface supports the stack of parcels and generates a stack pressure in a direction of the drawing element. At least one first nozzle disposed in the region of the support surface, and/or the region of the guide wall, blows compressed air between the parcels in the stack. At least one second nozzle, disposed in the region of the gap, between the stack of parcels and the guide wall, blows compressed air having a predetermined inclination counter to the conveying direction of the parcels to be drawn off.

Abstract: A labeller head using the Bernoulli Effect is suited for applying thin, flexible, pressure sensitive labels (14, 106) of the type having a first, display side and a second, adhesive side, and includes a body having a rigid or resilient support surface (52, 64, 102, 104); a plenum (54) within the body; a plurality of bores (56, 74, 86-90, 114) extending from the plenum through the support surface, the bores being angled with respect to the support surface and arranged in an array so that jets of gas issuing from the array will cause the label to be drawn onto the support surface when the label is presented to the support surface and the first, display side is brought into close proximity of the jets, thereby causing a zone of reduced gas pressure to be formed between the support surface and the first, display side and establishing a pressure differential across the label to hold the label on a film of gas flowing over the support surface; a source of pressurized gas (58) for directing gas into the plenum and t

Abstract: A machine includes a scheme for detecting the level of curl in sheets in a stack by measuring the time it takes to acquire a sheet with a bottom corrugation vacuum feeder (BVCF). A vacuum switch changes state at a preset vacuum level thereby detecting any significant rise in vacuum which occurs when a sheet has been acquired by the BCVF. A digital control circuit senses the change of state which takes place in the vacuum switch and feeds a signal to the machine's microprocessor which in turn signals an air knife in the BVCF to increase or decrease air pressure toward the sheet stack to compensate for the stressed state of the sheets.

Abstract: Sheet feeder of a printing press having suckers for seizing an uppermost sheet of a sheet pile at a leading end of the uppermost sheet, at least one sheet-pile stop having an upper edge over which the uppermost sheet is liftable, and a pair of transport rollers to which the uppermost sheet is feedable includes grooves formed in the sheet-pile stop and extending parallel to leading and trailing edges of the sheets on the sheet pile.

Abstract: A top vacuum corrugation feeder with optimized performance for a large variation in sheet sizes is obtained by adjusting the vacuum port area of a vacuum chamber simply by the action of adjusting the paper guides in the paper tray for different sheet sizes.

Abstract: Apparatus and a method for merging vertically oriented documents with horizontally oriented documents. The apparatus includes: a document assembler for receiving vertically oriented documents, the document assembler having a pair of parallel paper paths, wherein each of the paper paths includes a device for transporting the vertically oriented documents and a device for stopping and a device for aligning the vertically oriented documents; a device located beneath the document assembler for re-orienting the documents from the document assembler in a vertical orientation to a horizontal orientation; and a horizontal transport located beneath the re-orienting device for feeding horizontally oriented documents toward the re-oriented documents emerging from the re-orienting device, whereby the horizontally oriented documents are merged with the re-oriented documents from the document assembler.

Abstract: A device whereby a pile of rectangular items is placed on an inclined surface and pushed towards the straight front edge thereof by a push unit. The surface presents two pairs of conveyor belts parallel to each other and coplanar with the surface; and the pile is arrested upon a bottom portion of the first item in the pile activating a first or second limit stop sensor, which activates a respective pair of belts so as to move the bottom left or right portion of the item and so orient the item in relation to a gripping plane. A gripping unit with two suction cups movable along a three-dimensional trajectory grips the oriented item and feeds it to a follow-up conveyor belt.

Abstract: A printing press feeder capable of sheet feeding from the rear, sheet feeding from the front, or stream feeding from the rear, using tracks above a stock support for the feeder, the sheet feeder head being movably mounted on these tracks, and a movable drive connection from a power source to the sheet feeder head for driving of the sheet pickup advancers in the different head positions. The sheet feeder has first and second alternate drive mechanisms, on opposite ends of the transverse drive shaft, the first drive mechanism having a variable speed drive for sheet feeding individual sheets and slowing feed of each sheet as the sheet approaches the print cylinder, and the second drive mechanism having a constant speed drive for stream feeding overlapping sheets to the print cylinder. The press has nonprint lift cylinders engaging the squeegee mount and actuable to lift the squeegee out of print position, but still within the stencil screen frame, to allow the stencil screen frame to cycle without printing.

Abstract: A device for feeding sheets from a sheet tray which minimizes mis-feeds and multi-feeds. The device includes a device detecting sheet properties such as sheet basis weight and sheet size, a device selecting appropriate air parameters, such as air plenum pressure, plenum flow, and air knife pressure based on the sheet properties detected, and a device adjusting air parameters based on the appropriate air parameters selected.

Abstract: Apparatus for feeding sheets seriatim from a sheet supply stack. The apparatus comprises a sheet feed head assembly including a plenum, a vacuum source in flow communication with the plenum, and a mechanism, such as a feed belt, for example, associated with the plenum for urging a sheet acquired by vacuum in a sheet feeding direction away from the sheet supply stack. The sheet supply stack is supported, for example in a hopper on a support platform, so as to maintain the topmost sheet in such stack at a predetermined level in spaced relation with respect to the urging mechanism of the sheet feed head assembly. A first positive air supply directs a flow of air at the sheet supply stack to levitate the top several sheets in the supply stack to an elevation enabling the topmost sheet to be acquired by vacuum from the sheet feed head assembly plenum; and a second positive air supply directs a flow of air at an acquired sheet to assure separation of any additional sheets adhering to such topmost sheet.

Abstract: Disclosed is a screen printing apparatus for filling minute through-holes in a board with conductive paste or the like by screen printing. When screen printing is performed with this screen printing apparatus, the board is placed on a stage through the intermediation of a film which is supplied to the stage by means of adhesive pads. The adhesive pads are brought into contact with the uppermost one of a plurality of stacked films to catch it by adhesion and then transfer the film to a position above the stage. Films are caught one after another by adhesion.

Abstract: In conjunction with an apparatus for seizing flat sheets on a stack of sheets arranged on a supply table (1), a sheet-separating device (10) is characterized by an air flow generator (15) and guide (A,B) designed to direct a turbulent air flow produced by the generator (15) on at least one side of the stack of sheets. The guide comprises a first tube (A) arranged so as to direct a flow of air produced by the generator (15) onto one side of the upper part of the stack of sheets (100) placed on the supply table (1) and a second tube (B) for directing an air flow produced by the generator (15) in the upper part of the free space (8) located under the sheet-seizing device (2).

Abstract: A photosensitive lithographic printing plate supplying apparatus includes a first suction device, which sucks an upper surface of an uppermost photosensitive lithographic printing plate of photosensitive lithographic printing plates stacked such that respective photosensitive surfaces thereof face downward and which raises the uppermost photosensitive lithographic printing plate, a second suction device, which sucks the upper surface of the raised uppermost photosensitive lithographic printing plate so as to support the photosensitive lithographic printing plate at one end thereof, and a rotating device which rotates the photosensitive lithographic printing plate supported on one end by the second suction device so that a photosensitive surface of the photosensitive lithographic printing plate faces upward. Accordingly, the photosensitive lithographic printing plates are supplied to an exposure device without the photosensitive surfaces thereof being contacted.

Abstract: A recycling automatic document feeder (RADF) for a copier or similar image forming apparatus and capable of preventing curled or otherwise deformed documents from being damaged when such documents are recirculated. The RADF includes a parting plate for separating part of a stack of documents not undergone illumination from the other part undergone illumination and returned to the stack. When the parting plate is raised to a level above a predetermined height, the RADF is inhibited from returning the illuminated documents to the stack.

Abstract: An air injection device including a housing defining an air duct therein and a valve associated with the air duct for controlling the flow of air therethrough from a pressure source (55). The valve has a sheet (59) of flexible material positioned within the air duct, the sheet (59) being mounted on a face (60) of the air duct with the ends of the sheet (59) restricted from moving in a direction substantially orthogonal to the face (60) but free to move in a direction parallel to the face (60). The sheet (59) is operably connected to control, such as a solenoid valve (62), for controlling the contour of the sheet (59), within an air flow passing through the air duct. In one embodiment a second sheet is positioned on the inside top face of the duct opposite the first sheet (59). The air injection device is particularly useful for application with a sheet separator-feeder.

Abstract: A bottom vacuum corrugated feeder (BVCF) includes a tray for supporting a stack of documents. The tray is angled downhill relative to the feeding direction of the documents such that the leading edge of the stack is urged to a common stop member. The tray also includes a single side guide for aligning one side edge of the stack. A stack height sensor sends a signal corresponding to stack height to a controller which in turn controls voltage to be applied to a DC motor controlled blower based on a predetermined ratio of air flow pressure to stack pressure. The structure enables intermixed size document feeding in a BVCF.

Abstract: Disclosed herein is a device for feeding sheets, one by one, from a stack of sheets stored in a sheet placement unit. The sheet feeding device basically comprises suction cups or pads facing one end of the edge of an uppermost sheet of the stacked sheets, for taking out the uppermost sheet, an engaging member located at the sheet placement unit, for supporting the leading ends in the withdrawal direction of the stacked sheets, and a roller disposed near the engaging member and positioned to face a cut-away portion in a portion of the engaging member facing the opposite end of the uppermost sheet, the opposite end being spaced away from the suction pads. The cut-away portion is formed to prevent the opposite end of the uppermost sheet from contacting with the engaging member due to hang down of the uppermost sheet. In addition, the cut-away portion is inclined downwards toward the opposite end of the uppermost sheet from the one end thereof.

Abstract: An air flow path switching device for a printing apparatus includes a sheet hopper which holds a plurality of sheets, a sheet switchback device for inverting the sheets so that both sides of the sheets can be printed on, sheet pickup devices associated, respectively, with the sheet hopper and the sheet switchback device for picking up sheets, and a blower device for supplying pressurized suction and discharge air to the sheet pickup devices. An air flow resistance existing in the sheet switchback device, when the sheet pickup device associated with the sheet hopper is connected to the blower, and an air flow resistance existing in the sheet switchback device, when the sheet pickup device associated with the sheet hopper is disconnected from the blower, are substantially equivalent.

Abstract: To enhance the separation of sheet materials from a destacker, an air provider mechanism is attached to a frame of the carriage to bias against the being lifted sheet so as to maintain the air steam provided by an air ejector of the system directed to a location substantially immediately beneath the bottom surface of the being lifted sheet. Accordingly, as the sheet is being picked up, the air ejected from the air ejector system is directed to the gap between the being lifted sheet and its underlying sheets to enhance the separation of the being lifted sheet and the underlying sheets.

Abstract: A method and apparatus is disclosed for laminating sheet material having a width together with at least one laminate web material having an adhesive coating on one side thereof. The laminating machine has upper and lower laminating rolls for producing therebetween a continuous laminated web comprising the sheet material and the web material fed between the laminating rolls. A laminate web material supply supplies material to the laminating rolls. Die cutting apparatus separates the continuous laminated web from the laminating rolls into individual laminated sheets, and an output area stacks the individual laminated sheets after they are separated. Apparatus is provided for pressing substantially the entire width of a marginal portion of a piece of sheet material to be laminated to the adhesive coating on the laminate web material.

Abstract: A separating jet blast air control assembly utilizes a regulating valve to control the amount of compressed air supplied to separating and fanning blowers of a sheet feeder. A valve disc that dumps excess compressed air is biased against a valve seat by a biasing spring. The force applied by the biasing spring is adjustable in accordance with an output from a controller in response to production speed, sheet characteristics and other variables.

Abstract: Air flows are jetted at leading edge of sheets from nozzles aligned along the widthwise direction of the sheets so as to separate the bottommost or uppermost sheet from the remaining sheets. When the sheets are large-sized, all the aligned nozzles form the air flows for separating the sheets. When the air flows from all the nozzles are jetted at the small-sized sheets, the sheets are liable to flap. Accordingly, the nozzles arranged near the both ends are closed, so that only the nozzles jetting the air flows to effectively separate the small-sized sheets are used.

Abstract: A sheet feeding apparatus enables the uppermost sheet in sequence in a stack of recording papers be lifted by air flow to separate and to convey the recording paper. The feeding apparatus comprises a laying plate on which plural sheets are stacked, a sheet feeding means disposed above the stacked sheets, which means partially deforms the first sheet in sequence by negative pressure at the leading end part of the sheet, and air forming means which injects air flow between the first sheet and the next sheet near the both ends in the widthwise direction of the recording paper, which flow comprises a straightforward air flow, and an air flow directed outwardly in the widthwise direction. The recording paper is separated from the next sheet by the air flow.

Abstract: A holder for receiving sheets and discharging sheets therefrom one-by-one from the bottom of a stack of sheets is provided including a carrier having a rear portion, an intermediate portion and a front portion, providing a carrying surface for the sheets, the carrier being bent at the intermediate portion thereof, transverse to the direction of conveyance of the sheets, so as to create a deepened section between the rear portion and the front portion. Lateral supports extend from lateral edges of the carrier, with at least one elevated part provided in the deepened section at the intermediate portion extending transverse to the direction of conveyance on the carrying surface of the carrier.

Abstract: Recording papers stacked up on a tray are conveyed as being attracted in vacuum by the conveying belt located above or beneath. To convey the recording papers one by one, air flow is blown to the front edge of the recording papers to separate. Accordingly, plural nozzles are disposed in the widthwise direction of the recording paper, and the air flows from the nozzles are directed to converge at the upstream side in the conveying direction front the front edges of the recording papers. By setting this converging position near the both ends in the widthwise direction of the recording papers, the recording papers may be separated securely and stably.

Abstract: When stacking up recording papers on a tray and conveying one by one from the top or bottom, they are conveyed by attracting in vacuum to a conveying belt. An example of conveying from the bottom is illustrated. When one recording paper is conveyed, its rear end comes into the attraction region of the conveying belt, and the second recording paper is attracted into the region out of the first recording paper in the attraction region, which results in duplicate feed. Therefore, the size of the attraction region is variable depending on the size of the recording paper so that the attraction region of the conveying belt may not come out from the rear end of the recording paper until the first recording paper is conveyed and its front end is held by the rear rollers of the conveying belt or the like.

Abstract: A sheet feeding apparatus for reconveying copy paper sheets carrying an image to a transfer section by suction. Along the transport path to the apparatus is arranged a curl inducing mechanism that induces curls in the copy paper sheets, whereby the copy paper sheets with upwardly curled edges are loaded in the apparatus. With this arrangement, the copy paper sheets are surely separated by injecting air, thereby preventing multi-feeds.

Abstract: Air flows from an air flow forming means are jetted to near the downstream end of a plurality of sheets stacked on a laying plate so as to separate either a uppermost sheet or a bottommost sheet from the remaining sheets. The uppermost sheet or the bottommost sheet is vacuum attracted to a vacuum attracting area defined in a feeding belt by a vacuum attracting box. Based on the size of the sheet, the open suction area uncovered by the stacked sheets in the vacuum attracting area is controlled, thereby enabling the feeding belt to control the power of suction thereof to the sheets. Accordingly, a multiple feeding of the sheets can be prevented due to an excessive power of suction.

Abstract: A suction table which, in a machine converting sheets into package, transfers the last, lowermost sheet of a batch to a subsequent processing station. The table is provided with numerous blowing and sucking nozzles and is fitted on a hollow frame movable with regard to a fixed distributory housing which provides sucking and blowing action. The housing comprises a distributory shaft and tubes movable with respect to the table and thereby sliding within corresponding guides formed in the frame. The shaft and tubes are provided with cooperating ducts which will allow the nozzles to suck or blow as required by the angular position of the distributory shaft and the position of the table.

Abstract: A sheet feeding apparatus comprising a sheet supporting device for supporting a stack of sheets, a vacuum transporting device adapted to suck a top sheet of the stack and transport it, and a device adapted to locate forcibly at least two portions of the top sheet away from the vacuum transporting device so as to corrugate the top sheet.

Abstract: Sheets such as photographic films are fed one by one by suction cups in an image recording system. A resilient sheet separator is brought into abutment against an uppermost one of stacked sheets, and then the suction cups are moved toward the uppermost sheet. Before the suction cups reach the uppermost sheet, they are activated to attract the uppermost sheet under suction. The sheet separator pushes the uppermost sheet in one direction and the suction cups draw the uppermost sheet in the opposite direction, so that the attracted uppermost sheet is greatly flexed fully out of contact with the next sheet of the sheet stack. Thereafter, the suction cups and the sheet separator are displaced away from the sheet stack, separating the uppermost sheet from the sheet stack. Air may be forcibly be introduced between the uppermost and next sheets, so that the remaining sheets can reliably be separated from the attracted uppermost sheet.

Abstract: A suction head for a feeder of a sheet-fed rotary printing press for feeding sheets of small format through the press in a given direction, including only one double sucker formed of two juxtaposed suction nozzles connected by a transverse tube and being disposed transversely to the feeding direction of the sheets, the only one double sucker being exchangeably secured at a center location of the printing press.

Abstract: An apparatus for individually feeding sheets from a stack of sheets, comprises a tray for supporting a stack of sheets to be fed therefrom. A sheet feeder is provided for individually capturing a top sheet from the stack and for conveying the top sheet out of the tray. A solenoid-activated sheet hold down device is provided which includes a portion being cyclically movable toward and away from the stack for exerting a force on a next top sheet beneath the top sheet to prevent the next top sheet from being forwarded out of the tray while the top sheet is being forwarded.

Abstract: A sheet feeder of a sheet-fed rotary printing press is provided with loosening blowers having controllable blowing power and being disposed so as to be adjustable in height on a frame of the sheet feeder behind and at the sides of a pile of sheets and including a plurality of fans for directing an air flow against a side face of the pile of sheets, the air flow being adjustable angularly with respect to the side face.

Abstract: Pressurized air and vacuum levels are controlled to facilitate sheet separation and feeding reliability based on the weight of a document sheet stack on the document sheet stack support. The weight of the stack is determined by counting the total number of individual document sheets in such document sheet stack, determining the height of the original topmost document sheet of such stack at a particular point in time, counting the number of individual document sheets fed from such stack from such particular point in time, computing the weight of each individual document sheet based on the counted number of document sheets from such particular point in time, and calculating the total weight of such stack based on the weight of each individual document sheet and the total number of document sheets in the such stack.

Abstract: A stack of sheets contained in a containing member is loosened at the downstream edges in the feeding direction by air injected from an air injecting device, and fed one by one seriatim from the sheet on top in a predetermined feeding direction by a vacuum suction feeder disposed above the containing member. At this time, an upwardly directed impact is applied to the downstream edges in the feeding direction of the sheets from an impact generating device, thereby improving looseness of the downstream edge faces in the feeding direction by the air.The sheet fed from the containing member is returned to the bottom of the stack of sheets on the containig member. At this time, a claw formed on a feed roller pushes up the upstream edges in the returning direction of the sheet so as to force the sheet completely into the containing member.