Electrostatic printing apparatus

Claim 2

A printing machine of the kind in which images are printed on sheet material at a printing station by electrostatically charging selected areas of the sheet at the printing station to attach pigmented particles to the electrostatically charged areas, and comprising, a first row of electrodes linearly aligned on one side of the sheet, a second row of electrodes linearly aligned on an opposite side of the sheet at the printing station, control means for supplying voltages to selected ones of the electrodes in the first and second rows to produce the electrostatic charge on the sheet including divider means for dividing the voltages between the two rows of electrodes in a manner such that a voltage supplied to any individual electrode in either the first or the second row is less than that required to produce the charge but is sufficient to produce the charge when added to the voltage on an opposed electrode in the opposite row, wherein the electrodes in the first row are stylus electrodes on a stylus board and are divided into groups having the same number of electrodes in each group and having correspondingly located and numbered electrodes in each group connected by a common supply line on the stylus board, each of the stylus electrode groups being further divided into two blocks with the first half of the electrodes in the group being located in an odd numbered block and the second half of the electrodes in the group being located in an even numbered block, and wherein the electrodes in the second row are segment electrodes with the length of each segment electrode being equal to the length along the stylus row of electrodes occupied by one block of the stylus electrodes, the row of segment electrodes being offset with respect to the stylus electrodes in a manner such that each block of stylus electrodes has one even numbered and one odd numbered segment electrode spanning the length of the block of stylus electrodes with one-half of the length of the even numbered segment electrode and one-half of the length of the odd numbered segment electrode extending beyond the ends of the block of stylus electrodes.

Claim 3

A pRinting machine as defined in claim 1 including control means for energizing both of the segment electrodes associated with a block of stylus electrodes when any stylus electrode in that block is selected for energization to print an area on the sheet opposite the stylus electrode.

Claim 4

A printing machine as defined in claim 2 including data register means connected to receive data for firing stylus electrodes in a block and associated with the control means to fire the stylus electrodes in that block after the data has been loaded in the register.

Claim 5

A printing machine as defined in claim 3 wherein the data register means are effective to start receiving data for the even block of stylus electrodes in a group after the data has been loaded in the register for the odd block and while the odd block of stylus electrodes is firing.

Claim 6

A printing machine as defined in claim 4 wherein the control means includes means for shifting energization of the segment electrodes from the first even numbered and first odd numbered segment electrodes to the first odd numbered and second even numbered segment electrodes as the firing of the first odd block of stylu electrodes is completed and as the firing of the second even block of stylus electrodes is to begin.

Claim 7

A printing machine as defined in claim 5 wherein the control means continue to shift the energization of the segment electrodes in pairs from adjacent even-odd to adjacent odd-even to adjacent even-odd to adjacent odd-even segment electrodes down the entire line of the segment electrodes in coordination with the firing of the related odd block of stylus electrodes, even block of stylus electrodes, odd block of stylus electrodes and even block of stylus electrodes until the entire line of stylus electrodes has been fired in blocks.

Claim 8

A printing machine of the kind in which data is printed on sheet material and comprising a printing station having electrodes which produce an electrostatic charge on certain areas of the sheet material at the printing station, a toner station at which pigmented particles are attached to the areas having the electrostatic charge to darken such areas and to thereby produce the printed image, said toner station being spaced from the printing station and located downstream of the printing station in the direction of movement of the sheet material, transport means including a drive roller for transporting the sheet material from the printing station to the toner station, and wherein said toner station comprises a toner trough at the toner station, supply means for supplying a liquid containing the pigmented particles to the trough, a toner roller associated with the drive roller and mounted to press against the sheet material on the drive roller and for rotation in a position in which the toner rollers picks up liquid from the trough and continuously applies the liquid to the surface of the sheet material as the sheet material is drawn between the drive roller and the toner roller and past the toner station, a reservoir, and drain means for regulating the level of the liquid in the toner trough and for returning excess liquid to the reservoir.

Claim 9

A printing machine of the kind in which data is printed on sheet material and comprising a printing station having electrodes which produce an electrostatic charge on certain areas of the sheet material at the printing station, a toner station at which pigmented particles are attached to the areas having the electrostatic charge to darken such areas and to thereby produce the printed image, said toner station being spaced from the printing station and located downstream of the printing station in the direction of movement of the sheet material, transport means including a drive roller for transporting the sheet material from the printing station to the toner station, and wherein said toner station comprises a toner trough at the toner station, supply means for supplying a liquid containing the pigmented particles to the trough, a toner roller associated with the drive roller and mounted to press against the sheet material on the drive roller and for rotation in a position in which the toner rollers picks up liquid from the trough and continuously applies the liquid to the surface of the sheet material as the sheet material is drawn between the drive roller and the toner roller and past the toner station, a reservoir, and drain means for regulating the level of the liquid in the toner trough and for returning excess liquid to the reservoir.

Claim 10

A printing machine as defined in claim 7 wherein the reservoir is located beneath the trough and wherein the supply means include a pump in a sump of the reservoir and a supply line running from the pump to the trough and wherein the drain includes a tube having an open upper end which establishes the level of the liquid in the trough and has a lower end which extends through the bottom of the trough and opens into the reservoir.

Claim 11

An electrode board for a printing machine of a kind in which data is printed on sheet material at a printing station by electrodes which are arranged in a line at the printing station and which are selectively energized to produce electrostatic charges on certain areas of the sheet material transported in a strip form through the printing station, said electrode board comprising, a board member of dielectric materiaL, a plurality of parallel arranged and closely spaced electrical conductors mounted on one side of the board member and having end surfaces linearly disposed along one part of the board to provide closely spaced electrode elements for producing electrostatic charges on the sheet material passing over that part of the board member, said electrodes being divided into groups along the length of said part of the board member with the same number of electrodes in each group, a lead extending downward from said part of the board for each electrode, each lead for each electrode in any one group having a different length than any lead of any other electrode in that group whereby the leads terminate at different vertical distances from said part of the board, each lead for each corresponding electrode in each group having the same length whereby the leads for corresponding electrodes in each group terminate at the same vertical distance from said part of the board, supply lines corresponding in number to the number of electrodes in each group mounted on the opposite side of the board member with each supply line aligned with the ends of one set of leads terminating at a given distance from said part of the board, and connection means extending through the board member and providing an electrical connection between such supply lines and the ends of the leads whereby each electrode in each group is connected in parallel with the corresponding electrode in each other group by a common supply line on the other side of the board.

Claim 12

An electrode board for a printing machine of a kind in which data is printed on sheet material at a printing station by electrodes which are arranged in a line at the printing station and which are selectively energized to produce electrostatic charges on certain areas of the sheet material transported in a strip form through the printing station, said electrode board comprising, a board member of dielectric materiaL, a plurality of parallel arranged and closely spaced electrical conductors mounted on one side of the board member and having end surfaces linearly disposed along one part of the board to provide closely spaced electrode elements for producing electrostatic charges on the sheet material passing over that part of the board member, said electrodes being divided into groups along the length of said part of the board member with the same number of electrodes in each group, a lead extending downward from said part of the board for each electrode, each lead for each electrode in any one group having a different length than any lead of any other electrode in that group whereby the leads terminate at different vertical distances from said part of the board, each lead for each corresponding electrode in each group having the same length whereby the leads for corresponding electrodes in each group terminate at the same vertical distance from said part of the board, supply lines corresponding in number to the number of electrodes in each group mounted on the opposite side of the board member with each supply line aligned with the ends of one set of leads terminating at a given distance from said part of the board, and connection means extending through the board member and providing an electrical connection between such supply lines and the ends of the leads whereby each electrode in each group is connected in parallel with the corresponding electrode in each other group by a common supply line on the other side of the board.

Claim 13

An electrode board as defined in claim 9 wherein the connecting means connecting the leads through the broad with the supply line on the other side of the board include holes drilled through the board member and electrically conductive coatings lining the holes.

Claim 14

An electrode board as defined in claim 9 wherein the supply lines terminate at one edge of the board and wherein plug-in connecters are attached to the ends of the supply lines at said edge of the board to permit the entire electrode board to be quickly plugged into a control circuit for controlling energization of electrodes in each of the groups.

Claim 15

An electrode board as defined in claim 10 wherein the lower ends of the leads include enlarged end portions through which the holes are drilled and wherein the leads are inclined at angles with respect to the electrodes to accommodate the enlarged areas of said end portions.

Claim 16

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet there between so that rotation of the drive roller and squeegee roller pulls the sheet from the storage compartment over the electrode means and through the toner means, said toner roller being mounted to press against the sheet material on the drive roller and a lid pivotally mounted above the storage compartment to provide access to the storage compartment.

Claim 17

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet there between so that rotation of the drive roller and squeegee roller pulls the sheet from the storage compartment over the electrode means and through the toner means, said toner roller being mounted to press against the sheet material on the drive roller and a lid pivotally mounted above the storage compartment to provide access to the storage compartment.

Claim 18

A printing machine as defined in claim 13 wherein the electrode means comprise a lower row of linearly aligned electrodes and an upper row of electrodes and wherein the upper row of electrodes and one of said two additional rollers are mounted at the front edge of the lid so that the lid can be opened and the sheet of material drawn between the two rows of electrodes and between the drive rollers without having to thread the sheet of material between these components and the lid can then be lowered into position to place the drive rollers in operative position.

Claim 19

A printing machine as defined in claim 13 wherein the toner means include an upper toner trough and a lower reservoir and pump means for supplying a liquid containing the pigmented particles from the reservoir to the toner trough and drain means for regulating the level of the toner liquid in the trough.

Claim 20

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment in the central part of the machine for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet therebetween so that rotation of the drive roller and squeegee rollers pulls the sheet from the storage compartment over the electrode means and through the toner means, a lid pivotally mounted above the storage compartment to provide access to the storage compartment, said printing machine including a card cage located behind the storage compartment and having height and width dimensions substantially the same as the corresponding dimensions of the storage compartment and logic cards in the card cage mounting electrical components for controlling the energization of the electrodes to produce selective charging of the areas of the sheet at the electrode means in response to signals supplied to the logic circuitry.

Claim 21

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment in the central part of the machine for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet therebetween so that rotation of the drive roller and squeegee rollers pulls the sheet from the storage compartment over the electrode means and through the toner means, a lid pivotally mounted above the storage compartment to provide access to the storage compartment, said printing machine including a card cage located behind the storage compartment and having height and width dimensions substantially the same as the corresponding dimensions of the storage compartment and logic cards in the card cage mounting electrical components for controlling the energization of the electrodes to produce selective charging of the areas of the sheet at the electrode means in response to signals supplied to the logic circuitry.

Claim 22

A printing machine as defined in claim 16 including electrical power components and mechanical drive components arranged along the length of the printing machine on one side and extending from the side of the toner means in the front of the machine to the side of card cage at the back of the printing machine whereby all the operating components of the printing machine are compactly contained within the machine and the overall height of the machine is just slightly greater than the depth of the storage compartment and the overall width of the printing machine is just slightly greater than width of the storage compartment.

Claim 23

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment in the central part of the machine for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet therebetween so that rotation of the drive roller and squeegee rollers pulls the sheet from the storage compartment over the electrode means and through the toner means, a lid pivotally mounted above the storage compartment to provide access to the storage compartment, and wherein the electrode means comprise a lower row of linearly aligned electrodes and an upper row of electrodes and wherein the upper row of electrodes and one of said two additional rollers are mounted at the front edge of the lid so that the lid can be opened and the sheet of material drawn between the two rows of electrodes and between the drive rollers withOut having to thread the sheet of material between these components and the lid can then be lowered into position to place the drive rollers in operative position and wherein the lower row of electrodes is mounted on a generally rectangular shaped electrode board disposed vertically in front of the storage compartment and the upper row of electrodes is mounted on a generally rectangular shaped electrode board mounted flat against the underside of the lid and wherein the printing machine includes a generally rectangular shaped connector board disposed parallel to the inside wall of the printing machine on the side of the storage compartment opposite the side along which the power components are disposed and wherein said connector board connects terminals on the first electrode board to terminals on the card cage.

Claim 24

A printing machine of the kind in which images are printed on a sheet by electrostatically charging selected areas of the sheet to attach pigmented particles to the selected areas, said printer comprising, a storage compartment in the central part of the machine for storing a supply of the sheet material, electrode means located closely adjacent one end of the storage compartment for producing the electrostatic charge on the sheet as the sheet is moved past the electrode means, toner means located in front of and closely adjacent to the electrode means and including a toner roller for applying pigmented particles to the electrostatically charged areas of the sheet, drive means associated with the toner roller and including a drive roller and a squeegee roller which frictionally engage the sheet therebetween so that rotation of the drive roller and squeegee rollers pulls the sheet from the storage compartment over the electrode means and through the toner means, a lid pivotally mounted above the storage compartment to provide access to the storage compartment, and wherein the electrode means comprise a lower row of linearly aligned electrodes and an upper row of electrodes and wherein the upper row of electrodes and one of said two additional rollers are mounted at the front edge of the lid so that the lid can be opened and the sheet of material drawn between the two rows of electrodes and between the drive rollers withOut having to thread the sheet of material between these components and the lid can then be lowered into position to place the drive rollers in operative position and wherein the lower row of electrodes is mounted on a generally rectangular shaped electrode board disposed vertically in front of the storage compartment and the upper row of electrodes is mounted on a generally rectangular shaped electrode board mounted flat against the underside of the lid and wherein the printing machine includes a generally rectangular shaped connector board disposed parallel to the inside wall of the printing machine on the side of the storage compartment opposite the side along which the power components are disposed and wherein said connector board connects terminals on the first electrode board to terminals on the card cage.