CA1222262A - Sheet feeding apparatus - Google Patents
Sheet feeding apparatusInfo
- Publication number
- CA1222262A CA1222262A CA000453001A CA453001A CA1222262A CA 1222262 A CA1222262 A CA 1222262A CA 000453001 A CA000453001 A CA 000453001A CA 453001 A CA453001 A CA 453001A CA 1222262 A CA1222262 A CA 1222262A
- Authority
- CA
- Canada
- Prior art keywords
- paper
- platen
- printer
- feeder
- sensing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
- B41J13/10—Sheet holders, retainers, movable guides, or stationary guides
- B41J13/103—Sheet holders, retainers, movable guides, or stationary guides for the sheet feeding section
Abstract
SHEET FEEDING APPARATUS
Abstract of the Invention A paper feeder for use in dispensing paper into a printer with sensors for leading and trailing edges of paper and with a platen which rotates in a forward imprinting direction in response to a leading edge and in a backward, paper-ejecting direction in response to a trailing edge, the paper feeder comprising a paper holder, at least one rotatable drive roller to operably contact paperin the holder, and a drive train connecting the platen to the roller and controlled exclusively by such connection to cause no roller rotation in response to forward platen rotation, and to cause roller rotation in a paper-dispensing direction in response to backward platen rotation; the drive train is arranged so that the roller delivers paper to a paper-loading position on the printer not before the platen completes paper ejection;
whereby backwards platen rotation provides simultaneous paper ejection and dispensing.
Abstract of the Invention A paper feeder for use in dispensing paper into a printer with sensors for leading and trailing edges of paper and with a platen which rotates in a forward imprinting direction in response to a leading edge and in a backward, paper-ejecting direction in response to a trailing edge, the paper feeder comprising a paper holder, at least one rotatable drive roller to operably contact paperin the holder, and a drive train connecting the platen to the roller and controlled exclusively by such connection to cause no roller rotation in response to forward platen rotation, and to cause roller rotation in a paper-dispensing direction in response to backward platen rotation; the drive train is arranged so that the roller delivers paper to a paper-loading position on the printer not before the platen completes paper ejection;
whereby backwards platen rotation provides simultaneous paper ejection and dispensing.
Description
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SHEET FE~DING APPARATUS
Back~round of the Invention This in~ention relates to paper feeders for use on printers having sensors for sensing paper presence, forward imprinting platen rotation and backward paper-rejecting platen rotation.
Such a printer is described in U.S.S.N7 204,020, where controls are provided to cause forward platen ro~ation for first, feeding a sheet of paper from an upper hopper to a paper load position at the bottom of the platen and then printing the sheet, and to cause backwards platen rotation foe ejecting the printed sheet -! downwardly toward a lower hopper for sequentially stacking the sheets of paper.
L5 It i6 desirable to provide such printers with a paper feeder that can dispense unprinted sheets of paper to the printer.
Summary of the Invention In one aspect, the invention features a paper feeder for dispensing sheets of paper, one at a time, into a printer having sensors for sensing leading and trailing edges of sheets of paper. The printer has a platen which rotates in a forward imprinting direction in response to sensing a leading edge, and rotates in a 25 backward, paper-ejecting direction in response to sensing a trailing edge. The feeder has a paper cartridge for holding a stack of paper and at least one rotatable drive roller to operably contact the topmost sheet of paper in the cartridge.
A drive train for connecting the platen to the drive roller is powered and controlled exclusively by its connection to the platen to cause no rotation of the ;~ drive roller in response to forward platen rotation, and to cause orward, paper-dispensing rotation of the drive 35 roller in response to backward platen rotationO When ,, ~2;~2;~,6~
the platen rotates backwards to eject a sheet of paper from the printer, the drive train causes the drive roller to move a sheet of paper from the cartridge into a paper-loading position on the printer, thus providing the printer with simultaneous paper ejection and dispensing. -The drive train is arranged so that the driveroller delivers sheets of paper to the paper-loading position not before the platen ejects the peinted sheet - 10 of paper. In preferred embodiments, the drive roller rotates at a velocity slower than the rotational velocity of the platen. In the illustrated embodiment, the ratio of platen rotation to drive roller rotation is approximately 2:1. In other embodiments, the drive train is arranged to cause the feeder to dispense sheets of paper over a greater distance than the maximum length of paper being ejected.
Therefore, the printer is provided with simultaneous paper ejection and dispensing, and the drive train provides that sheets of paper are not delivered to the paper-loading position before the platen ejects the printed sheet of paper.
In other aspects of the invention, the invention feature a printer having sensors for sensing leading and trailing edges of sheets of paper, control means for controlling platen rotation in response to the sensing, a paper feeder arranged to dispense sheets of paper, and a drive train for connecting the paper feeder to a platen. The control means are responsive to sensing a leading edge and completion of paper ejection, causing the platen to rotate in a forward imprinting direction. The control means provide simultaneous paper ejection from and paper feeding into the printer solely through sensing a trailing edge and causing the platen 35 to rotate a predetermined amount first in a forward imprinting direction and second in A backward paper-ejecting direction. The drive train responds solely to backward, paper-ejecting p3aten rotation to dispense a sheet of paper from the feeder, and is arranged so that ~he paper feeder delivers sheets of paper to a paper-loading position on the printer not before the platen ejects the printed sheet of paper.
In still further aspects of the invention, the ~, invention feature a printer having sensors for sensing the presence of a sheet of paper, a paper feeder, a drive train, and programmed control means which provide simultaneous paper ejection frorn and paper feeding into the printer solel~ through conteolling rotation of the platen in response to sensing paper presence. The drive train responds solely to paper-ejecting platen rotation to dispense a sheet of paper from the feeder, and is arranged so that the feeder delivers sheets of paper to a paper-loading position on the printer not before the platen ejects the printed sheet of paper.
In preferred embodiments, the programmed control means respond to sensing no paper at start-up of the printer, by causing the platen to rotate a predetermined amount in a paper~ejecting direction, which causes the feeder to dispense a sheet of paper.
The control means respond to a trailing edge, causing the platen to rotate a predetermined amount first in a paper-imprinting direction and second in a paper-ejecting direction. At the completion of paper ejection, the control means respond to a leading edge, causing the platen to rotate in a forward paper-imprinting direction, and respond to sensing no paper, causing the printer to deselect.
Also in preferred embodiments, the paper feeder is releasably attached to the printer and has 3 disengaging means for disengaging, without removing, the paper feeder from the printer by eliminating operable contact between the stack of paper and the drive roller. In the illustrated embodiment, a pusher plate biase~ against the stack of paper in the cartridge provides the operable contact, and manipulation of a select knob, connected to a pusher rod, cause~s the pusher rod to move the pusher plate away from the s~ack, thereby eliminating the operable contact.
Other advantages and features of the invention will be apparent from the following description of the preferred embodiment thereof, and from the claims.
Descri~tion of the Preferred Embodiment . _ _ We turn now to the structure and cperation of the preEerred embodiment first briefly describing the drawings thereof.
Drawings Fig. 1 is an exploded view of the preferred embodiment of the invention, with parts broken away for clarity.
Fig. 2 is a side view of Fig. 1, with parts ! broken away for clarity.
Fig. 3 is the opposite side view of Fig. 1, with parts broken away for clarity.
Description As seen in Figs. 2 and 3, a paper feeder 10 is attached to one side of printer 50 by spring clip 5~, and to the opposite side of machine 50 by catch 54.
Components of printer 50 include platen 60 fixedly mounted on platen shaft 61, and paper-loading guide 56 to guide the unprinted sheet of paper to the loading position of platen 60 at the edge of the lower platen feed roll and guide mechanism 57. An optical q~ sensor 58 mounted on guide S6 is provided to sense the leading and trailing edges of paper, and platen controls ~2~;~Z~;~
63 are provided to control the amount and direction of platen rotation in response to signals from sensor 58.
Lower platen feed roll and guide mechanism 57 includes an arcuate platen feed guide 66 provided under platen 60 and arranged to be biased so that the plurality of platen guide rollers 59 rotatably mounted on feed guide 66 normally contact platen 60. A printecl sheet deflection guide 65 is provided to guide printed paper around platen 60 and between platen 60 and printed sheet rollers 64 mounted coaxially with ancl normally contacting platen 60.
To understand the arrangement of the printer to which the feeder is attached, a short explanation of paper feeding, printing and ejection follows. As a leading edge of an unprinted sheet of paper is sensed by sensor 58, platen controls 63 cause platen 60 to rotate in a forward direction one quarter of a revolution to bring the sheet to the loading position of the platen at the edge of mechanism 57. Platen conteols 63 continue to cause forward platen rotation so as to print the sheet of paper, which is pulled around platen 60 by platen guide rollers 59 which are biased against platen 60. Printed sheet deflection guide 65 guides printed paper upward around platen 60 and between platen 60 and printed sheet rollers 64.
When a trailing edge of a sheet of paper is sensed by sensor 58, controls 63 again cause platen 60 to rotate in a forward direction one ~uarter of a revolution to bring the sheet out from under platen feed guide 66. Platen controls 63 then cause platen 60 to reverse direction to rotate backwards and eject the printed piece of paper. Printed sheet rollers 64 bear ' against platen 60 to aid in ejecting the printed paper,
SHEET FE~DING APPARATUS
Back~round of the Invention This in~ention relates to paper feeders for use on printers having sensors for sensing paper presence, forward imprinting platen rotation and backward paper-rejecting platen rotation.
Such a printer is described in U.S.S.N7 204,020, where controls are provided to cause forward platen ro~ation for first, feeding a sheet of paper from an upper hopper to a paper load position at the bottom of the platen and then printing the sheet, and to cause backwards platen rotation foe ejecting the printed sheet -! downwardly toward a lower hopper for sequentially stacking the sheets of paper.
L5 It i6 desirable to provide such printers with a paper feeder that can dispense unprinted sheets of paper to the printer.
Summary of the Invention In one aspect, the invention features a paper feeder for dispensing sheets of paper, one at a time, into a printer having sensors for sensing leading and trailing edges of sheets of paper. The printer has a platen which rotates in a forward imprinting direction in response to sensing a leading edge, and rotates in a 25 backward, paper-ejecting direction in response to sensing a trailing edge. The feeder has a paper cartridge for holding a stack of paper and at least one rotatable drive roller to operably contact the topmost sheet of paper in the cartridge.
A drive train for connecting the platen to the drive roller is powered and controlled exclusively by its connection to the platen to cause no rotation of the ;~ drive roller in response to forward platen rotation, and to cause orward, paper-dispensing rotation of the drive 35 roller in response to backward platen rotationO When ,, ~2;~2;~,6~
the platen rotates backwards to eject a sheet of paper from the printer, the drive train causes the drive roller to move a sheet of paper from the cartridge into a paper-loading position on the printer, thus providing the printer with simultaneous paper ejection and dispensing. -The drive train is arranged so that the driveroller delivers sheets of paper to the paper-loading position not before the platen ejects the peinted sheet - 10 of paper. In preferred embodiments, the drive roller rotates at a velocity slower than the rotational velocity of the platen. In the illustrated embodiment, the ratio of platen rotation to drive roller rotation is approximately 2:1. In other embodiments, the drive train is arranged to cause the feeder to dispense sheets of paper over a greater distance than the maximum length of paper being ejected.
Therefore, the printer is provided with simultaneous paper ejection and dispensing, and the drive train provides that sheets of paper are not delivered to the paper-loading position before the platen ejects the printed sheet of paper.
In other aspects of the invention, the invention feature a printer having sensors for sensing leading and trailing edges of sheets of paper, control means for controlling platen rotation in response to the sensing, a paper feeder arranged to dispense sheets of paper, and a drive train for connecting the paper feeder to a platen. The control means are responsive to sensing a leading edge and completion of paper ejection, causing the platen to rotate in a forward imprinting direction. The control means provide simultaneous paper ejection from and paper feeding into the printer solely through sensing a trailing edge and causing the platen 35 to rotate a predetermined amount first in a forward imprinting direction and second in A backward paper-ejecting direction. The drive train responds solely to backward, paper-ejecting p3aten rotation to dispense a sheet of paper from the feeder, and is arranged so that ~he paper feeder delivers sheets of paper to a paper-loading position on the printer not before the platen ejects the printed sheet of paper.
In still further aspects of the invention, the ~, invention feature a printer having sensors for sensing the presence of a sheet of paper, a paper feeder, a drive train, and programmed control means which provide simultaneous paper ejection frorn and paper feeding into the printer solel~ through conteolling rotation of the platen in response to sensing paper presence. The drive train responds solely to paper-ejecting platen rotation to dispense a sheet of paper from the feeder, and is arranged so that the feeder delivers sheets of paper to a paper-loading position on the printer not before the platen ejects the printed sheet of paper.
In preferred embodiments, the programmed control means respond to sensing no paper at start-up of the printer, by causing the platen to rotate a predetermined amount in a paper~ejecting direction, which causes the feeder to dispense a sheet of paper.
The control means respond to a trailing edge, causing the platen to rotate a predetermined amount first in a paper-imprinting direction and second in a paper-ejecting direction. At the completion of paper ejection, the control means respond to a leading edge, causing the platen to rotate in a forward paper-imprinting direction, and respond to sensing no paper, causing the printer to deselect.
Also in preferred embodiments, the paper feeder is releasably attached to the printer and has 3 disengaging means for disengaging, without removing, the paper feeder from the printer by eliminating operable contact between the stack of paper and the drive roller. In the illustrated embodiment, a pusher plate biase~ against the stack of paper in the cartridge provides the operable contact, and manipulation of a select knob, connected to a pusher rod, cause~s the pusher rod to move the pusher plate away from the s~ack, thereby eliminating the operable contact.
Other advantages and features of the invention will be apparent from the following description of the preferred embodiment thereof, and from the claims.
Descri~tion of the Preferred Embodiment . _ _ We turn now to the structure and cperation of the preEerred embodiment first briefly describing the drawings thereof.
Drawings Fig. 1 is an exploded view of the preferred embodiment of the invention, with parts broken away for clarity.
Fig. 2 is a side view of Fig. 1, with parts ! broken away for clarity.
Fig. 3 is the opposite side view of Fig. 1, with parts broken away for clarity.
Description As seen in Figs. 2 and 3, a paper feeder 10 is attached to one side of printer 50 by spring clip 5~, and to the opposite side of machine 50 by catch 54.
Components of printer 50 include platen 60 fixedly mounted on platen shaft 61, and paper-loading guide 56 to guide the unprinted sheet of paper to the loading position of platen 60 at the edge of the lower platen feed roll and guide mechanism 57. An optical q~ sensor 58 mounted on guide S6 is provided to sense the leading and trailing edges of paper, and platen controls ~2~;~Z~;~
63 are provided to control the amount and direction of platen rotation in response to signals from sensor 58.
Lower platen feed roll and guide mechanism 57 includes an arcuate platen feed guide 66 provided under platen 60 and arranged to be biased so that the plurality of platen guide rollers 59 rotatably mounted on feed guide 66 normally contact platen 60. A printecl sheet deflection guide 65 is provided to guide printed paper around platen 60 and between platen 60 and printed sheet rollers 64 mounted coaxially with ancl normally contacting platen 60.
To understand the arrangement of the printer to which the feeder is attached, a short explanation of paper feeding, printing and ejection follows. As a leading edge of an unprinted sheet of paper is sensed by sensor 58, platen controls 63 cause platen 60 to rotate in a forward direction one quarter of a revolution to bring the sheet to the loading position of the platen at the edge of mechanism 57. Platen conteols 63 continue to cause forward platen rotation so as to print the sheet of paper, which is pulled around platen 60 by platen guide rollers 59 which are biased against platen 60. Printed sheet deflection guide 65 guides printed paper upward around platen 60 and between platen 60 and printed sheet rollers 64.
When a trailing edge of a sheet of paper is sensed by sensor 58, controls 63 again cause platen 60 to rotate in a forward direction one ~uarter of a revolution to bring the sheet out from under platen feed guide 66. Platen controls 63 then cause platen 60 to reverse direction to rotate backwards and eject the printed piece of paper. Printed sheet rollers 64 bear ' against platen 60 to aid in ejecting the printed paper,
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and printed sheet de~lection guide 65 directs the printed sheet downward toward a lower hopper (not shown) under the platen~
The paper feeder 10 attached to printer 50 has 5 a removable paper cartridge 12 in which a stack of paper is held. In the lower two corners of cartridge 12 are trippers 14 arranged to separate the topmost sheet in cartridge 12 from the rest of the stack 60 as to allow feeder 10 to efficiently dispense one sheet of paper at 10 a time.
Along the interior vertical length of cactridge 12 are insert guides (not shown) arranged so that vertica' cartridge inserts (not shown) can be inserted into cartridge 12, thus altering the width of cartridge 15 12 so that paper of different widths (i.e. 8, 8 1/4, 8 1/2 inches) may be stacked in cartridge 12.
As seen in Fig. 2, cartridge 12 is supported within ~eeder 10 by cartridge runners 18 which extend along the vertical length of paper cartridge 12 and fit 20 over cartridge guide 16 extending along the vertical interior length of feeder 10. Cartridge guide 16 is arranged on the interior wall of feeder 10 so that cartridge 12 is held between drive rollers 20 and pusher plate 24.
Drive rollers 20 are fixedly mounted on feeder drive shaft 22, which extends transversely across feeder 10, and pusher plate 24 in the back of feeder 10 is urged toward drive rollers 20 by spring 26 in order to provide operable contact between the topmost sheet of paper in cartridge 12 and drive rollers 20. Pusher rod 30, extending transversely across feeder 10 between pusher plate 24 and rollers 20 are arranged to move pusher plate 24 away from cartridge 12 so as to remove the operable contact between the paper in cartridge 12 and drive rollers 20.
6;~
Select knob 32, mounted to pusher rod 30 on the exterior of feeder 10, is arranged to move p~sher rod 30 toward and away from pusher plate 24. In Fig. 2, the extreme pOSitiOlS of pusher plate 24 are shown; first, in solid lines, as causing operable contact between the stack of paper and drive rollers 20, and second, in phanto~, as moved a~ay Erom drive rollers 20, th~ls removing operable contact and deselecting automatic - feeding.
As also seen in Fig. 3, eeder drive rollers 20 are connected to platen 60 through through drive tr~in 35, a series of gears and pulleys. Fixedly mounted to platen shaf~ 61 is platen gear 62 which is mounted coaxially with and engages plater. gear/pulley 34.
Timing belt 36 is arranged to transfer rotation from platen gear/pulley 3~ to one-way feeder pulley 38 which is mounted on the end of drive shaft 22.
One-way feeder pulley 38 is so constructed to engage with and rotate drive shaft 22 and rollers 20 when timing belt 36 moves counter-clockwise, shown as "a" in Fig. 3, and to rotate freely without engaging drive shaft 22 when timing belt 36 moves clockwise, as shown as "b" in Fig. 3.
Drive train 35 is arranged so that feeder drive rollers 20 rotate exclusively in response to specific directional rotation of platen 60, in a direction opposite to that of platen 60 and at a frequency proportional to the rotational fre~uency of platen 60.
This arrangement provides that the prede~ermined amount of backward platen rotation necessary to eject a printed sheet of paper of maximum length simultaneously causes ; automatic dispensing of an unprinted sheet of paper into the platen paper-loading position at a time not before completion of the printed sheet ejection or at least not before rnost of the printed sheet has been ejected.
s~
In the ill~strated embodi~ent, the rotational fre~ency of drive rollers 20 is smaller than the rotatlonal frequency of platen 60; the platen/drive roller frequency ratio is appriximately 2:1. In other embodiments, a drive train may be arranqed so that the platen and drive rollers rotat.e with approximately e~ual fre~uencies, but that the paper feeder dispenses sheets of paper to the printer over a greater d.istance than the maximum length of paper being ejected.
Operation When sheet feeder l0 is attached to printer 50 and select knob 32 is turned so that pusher rod 30 mQves pusher plate 24 away from drive roller 20, automatic sheet feeding is not selected. Automatic sheet feeding is selected when knob 32 is turned to move pusher rod 30 away from pusher plate 24 so that plate 24, normally biased by spring 26 toward drive roller 20, presses the stack of paper within cartridge 12 against drive roller 20, thus providing operable contact between the topmost sheet of paper and drive rollers 20.
When automatic sheet feeding is selected and the printer is first turned on, platen controls 63 within printer 50 rotate platen 60 in a backward direction so as to cause an unprinted sheet of paper to be dispensed from feeder l0 onto paper-loading guide 56. As seen as "a" in Fig. 3, drive train 35 transfers the backward rotation of platen 60 into a counter-clockwise, paper dispensing rotation of drive shaft 22 and rollers 20. Specifically, the backward rotation of platen 60 and platen shaft 61 causes clockwise rotation of platen gear 62, which engages gear/pulley 34 and rotates it in a co~lnter-clockwise direction. Timing belt 36 transfers the counter clockwise rotation of platen gear/pulley 34 to ~ 3 one-way feeder pulle-~ 3~, which causes drive shaft 22 and rollers ~0 to rotate in a counter-clockwise, paper-dispensing direction, pushing a piece of paper do~n onto the printer's paper-loading guide 56.
When the leading edge of the unprinted sheet of paper is sensed on paper-loading guide 56 by sensor 58, platen controls 63 cause platen 60 to rotate in a forward direction one ~uarter of a revolution to bring the sheet to the loading position of platen 60. Platen lO controls 63 continue to cause forward platen rotation so as to print the sheet of paper. Platen g~ide rollers 59, bearing against platen 60, guide paper ~nder and arcund platen 60, and printed sheet rollers 6~/ bearing against platen 60, grip printed paper that has passed 15 around platen 60.
During paper printing, drive train 35 does not transfer the forward rotation of platen 60 to drive shaft 22 and rollers 20. Specifically, as seen as "b"
in Fig. 3, the forward rota~ion of platen 60 and platen 20 shaft 61 causes counter-clockwise rotation of platen platen gear 62 and clockwise rotation of gear/pulley 34. Timing belt 36 transfers the clockwise rotation to one-way feeder pulley 38, which rotates clockwise without engaging drive shaft 22 and rollers 20.
i 25 Forward paper-imprinting platen rotation continues until sensor 58 senses the trailing edge oE
the sheet of paper being imprinted. At that time, platen controls 63 cause platen 60 to rotate in a forward direction one quarter of a revolution to bring 30 the now-imprinted sheet out from under platen feed guide 66. Platen controls 63 then cause platen 60 to reverse direc~ion to rotate backwards a predetermined number of -~ times so as to eject the printed piece of paper in a downward direction. Printed sheet rollers 64 aid in the ;2 ejection, bearing against the printed sheet and platen 60. Printed sheet deflec~ioll guide 65 guides the sheet in its downward path to the :Lower hopper (not shown).
The amount of backwards platen rotation is chosen to allow thé entire length of a piece of paper having predetermined maximum length to pass between platen rollers 64 and platen 60.
As platen 60 is rotating baclcwards to eject the rinted piece of paper, drive train 35 is transferrinq the back~ards platen rotation to the drive shaft 22 and rollers 20 so as to cause the next unprinted sheet of paper to be dispensed from feeder 10 onto paper-loading guide 56. The operation of drive train 35 is identical to its operation described in causing paper Eeed during printer initiation, i.e., backward, paper-ejecting rotation of platen 60 and shaft 61 causes counter-clockwise, paper-dispensing rotation of drive shaft 22 and rollers 20.
The newly dispensed sheet of paper is fed onto printer paper-loading guide 56, but sensor 58 does not sense its presence until the platen has completed the predetermined number of backward, paper-ejecting rotations. An insubstantial amount of buckle may appear in the newly dispensed sheet while it lies on guide 56.
After ejection is completed and sensor 58 senses the newly-dispensed sheet of paper on paper-loading guide 56, platen controls 63 cause platen 60 to begin the paper loading and imprintiny sequence described above. If, for some reason, a newly-dispensed sheet of paper is not sensed by sensor 58, i.e., paper cartridge 12 was empty, platen controls 63 cause printer 50 to deselect.
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Various modifications of the invention within the spirit of the invention and scope of the appended claims will be apparent to those skilled in the printing apparatus art.
and printed sheet de~lection guide 65 directs the printed sheet downward toward a lower hopper (not shown) under the platen~
The paper feeder 10 attached to printer 50 has 5 a removable paper cartridge 12 in which a stack of paper is held. In the lower two corners of cartridge 12 are trippers 14 arranged to separate the topmost sheet in cartridge 12 from the rest of the stack 60 as to allow feeder 10 to efficiently dispense one sheet of paper at 10 a time.
Along the interior vertical length of cactridge 12 are insert guides (not shown) arranged so that vertica' cartridge inserts (not shown) can be inserted into cartridge 12, thus altering the width of cartridge 15 12 so that paper of different widths (i.e. 8, 8 1/4, 8 1/2 inches) may be stacked in cartridge 12.
As seen in Fig. 2, cartridge 12 is supported within ~eeder 10 by cartridge runners 18 which extend along the vertical length of paper cartridge 12 and fit 20 over cartridge guide 16 extending along the vertical interior length of feeder 10. Cartridge guide 16 is arranged on the interior wall of feeder 10 so that cartridge 12 is held between drive rollers 20 and pusher plate 24.
Drive rollers 20 are fixedly mounted on feeder drive shaft 22, which extends transversely across feeder 10, and pusher plate 24 in the back of feeder 10 is urged toward drive rollers 20 by spring 26 in order to provide operable contact between the topmost sheet of paper in cartridge 12 and drive rollers 20. Pusher rod 30, extending transversely across feeder 10 between pusher plate 24 and rollers 20 are arranged to move pusher plate 24 away from cartridge 12 so as to remove the operable contact between the paper in cartridge 12 and drive rollers 20.
6;~
Select knob 32, mounted to pusher rod 30 on the exterior of feeder 10, is arranged to move p~sher rod 30 toward and away from pusher plate 24. In Fig. 2, the extreme pOSitiOlS of pusher plate 24 are shown; first, in solid lines, as causing operable contact between the stack of paper and drive rollers 20, and second, in phanto~, as moved a~ay Erom drive rollers 20, th~ls removing operable contact and deselecting automatic - feeding.
As also seen in Fig. 3, eeder drive rollers 20 are connected to platen 60 through through drive tr~in 35, a series of gears and pulleys. Fixedly mounted to platen shaf~ 61 is platen gear 62 which is mounted coaxially with and engages plater. gear/pulley 34.
Timing belt 36 is arranged to transfer rotation from platen gear/pulley 3~ to one-way feeder pulley 38 which is mounted on the end of drive shaft 22.
One-way feeder pulley 38 is so constructed to engage with and rotate drive shaft 22 and rollers 20 when timing belt 36 moves counter-clockwise, shown as "a" in Fig. 3, and to rotate freely without engaging drive shaft 22 when timing belt 36 moves clockwise, as shown as "b" in Fig. 3.
Drive train 35 is arranged so that feeder drive rollers 20 rotate exclusively in response to specific directional rotation of platen 60, in a direction opposite to that of platen 60 and at a frequency proportional to the rotational fre~uency of platen 60.
This arrangement provides that the prede~ermined amount of backward platen rotation necessary to eject a printed sheet of paper of maximum length simultaneously causes ; automatic dispensing of an unprinted sheet of paper into the platen paper-loading position at a time not before completion of the printed sheet ejection or at least not before rnost of the printed sheet has been ejected.
s~
In the ill~strated embodi~ent, the rotational fre~ency of drive rollers 20 is smaller than the rotatlonal frequency of platen 60; the platen/drive roller frequency ratio is appriximately 2:1. In other embodiments, a drive train may be arranqed so that the platen and drive rollers rotat.e with approximately e~ual fre~uencies, but that the paper feeder dispenses sheets of paper to the printer over a greater d.istance than the maximum length of paper being ejected.
Operation When sheet feeder l0 is attached to printer 50 and select knob 32 is turned so that pusher rod 30 mQves pusher plate 24 away from drive roller 20, automatic sheet feeding is not selected. Automatic sheet feeding is selected when knob 32 is turned to move pusher rod 30 away from pusher plate 24 so that plate 24, normally biased by spring 26 toward drive roller 20, presses the stack of paper within cartridge 12 against drive roller 20, thus providing operable contact between the topmost sheet of paper and drive rollers 20.
When automatic sheet feeding is selected and the printer is first turned on, platen controls 63 within printer 50 rotate platen 60 in a backward direction so as to cause an unprinted sheet of paper to be dispensed from feeder l0 onto paper-loading guide 56. As seen as "a" in Fig. 3, drive train 35 transfers the backward rotation of platen 60 into a counter-clockwise, paper dispensing rotation of drive shaft 22 and rollers 20. Specifically, the backward rotation of platen 60 and platen shaft 61 causes clockwise rotation of platen gear 62, which engages gear/pulley 34 and rotates it in a co~lnter-clockwise direction. Timing belt 36 transfers the counter clockwise rotation of platen gear/pulley 34 to ~ 3 one-way feeder pulle-~ 3~, which causes drive shaft 22 and rollers ~0 to rotate in a counter-clockwise, paper-dispensing direction, pushing a piece of paper do~n onto the printer's paper-loading guide 56.
When the leading edge of the unprinted sheet of paper is sensed on paper-loading guide 56 by sensor 58, platen controls 63 cause platen 60 to rotate in a forward direction one ~uarter of a revolution to bring the sheet to the loading position of platen 60. Platen lO controls 63 continue to cause forward platen rotation so as to print the sheet of paper. Platen g~ide rollers 59, bearing against platen 60, guide paper ~nder and arcund platen 60, and printed sheet rollers 6~/ bearing against platen 60, grip printed paper that has passed 15 around platen 60.
During paper printing, drive train 35 does not transfer the forward rotation of platen 60 to drive shaft 22 and rollers 20. Specifically, as seen as "b"
in Fig. 3, the forward rota~ion of platen 60 and platen 20 shaft 61 causes counter-clockwise rotation of platen platen gear 62 and clockwise rotation of gear/pulley 34. Timing belt 36 transfers the clockwise rotation to one-way feeder pulley 38, which rotates clockwise without engaging drive shaft 22 and rollers 20.
i 25 Forward paper-imprinting platen rotation continues until sensor 58 senses the trailing edge oE
the sheet of paper being imprinted. At that time, platen controls 63 cause platen 60 to rotate in a forward direction one quarter of a revolution to bring 30 the now-imprinted sheet out from under platen feed guide 66. Platen controls 63 then cause platen 60 to reverse direc~ion to rotate backwards a predetermined number of -~ times so as to eject the printed piece of paper in a downward direction. Printed sheet rollers 64 aid in the ;2 ejection, bearing against the printed sheet and platen 60. Printed sheet deflec~ioll guide 65 guides the sheet in its downward path to the :Lower hopper (not shown).
The amount of backwards platen rotation is chosen to allow thé entire length of a piece of paper having predetermined maximum length to pass between platen rollers 64 and platen 60.
As platen 60 is rotating baclcwards to eject the rinted piece of paper, drive train 35 is transferrinq the back~ards platen rotation to the drive shaft 22 and rollers 20 so as to cause the next unprinted sheet of paper to be dispensed from feeder 10 onto paper-loading guide 56. The operation of drive train 35 is identical to its operation described in causing paper Eeed during printer initiation, i.e., backward, paper-ejecting rotation of platen 60 and shaft 61 causes counter-clockwise, paper-dispensing rotation of drive shaft 22 and rollers 20.
The newly dispensed sheet of paper is fed onto printer paper-loading guide 56, but sensor 58 does not sense its presence until the platen has completed the predetermined number of backward, paper-ejecting rotations. An insubstantial amount of buckle may appear in the newly dispensed sheet while it lies on guide 56.
After ejection is completed and sensor 58 senses the newly-dispensed sheet of paper on paper-loading guide 56, platen controls 63 cause platen 60 to begin the paper loading and imprintiny sequence described above. If, for some reason, a newly-dispensed sheet of paper is not sensed by sensor 58, i.e., paper cartridge 12 was empty, platen controls 63 cause printer 50 to deselect.
(~
Various modifications of the invention within the spirit of the invention and scope of the appended claims will be apparent to those skilled in the printing apparatus art.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A paper feeder for use in dispensing sheets of paper, one sheet at a time, into a printer having sensing means for sensing leading and trailing edges of sheets of paper, said printer further having a platen which rotates in a forward imprinting direction in response to sensing a leading edge, and rotates in a backward, paper-ejecting direction in response to sensing a trailing edge, said paper feeder comprising:
a paper holder arranged to hold sheets of paper;
at least one rotatable drive roller disposed to operably contact said sheets of paper to be dispensed;
and a drive train for connecting said platen to said drive roller, said drive train being powered and controlled exclusively by its connection to said platen to cause no rotation of said drive roller in response to forward, paper-imprinting platen rotation, and to cause rotation of said drive roller in a forward, paper-dispensing direction in response to backward, paper-ejecting platen rotation, said drive train further arranged so that said drive roller delivers sheets of paper to a paper-loading position on said printer not before said platen ejects said printed sheet of paper;
whereby, when said platen rotates backwards to eject a sheet of paper from said printer and to cause said drive roller to move one of said sheets of paper into a paper-loading position on said printer, said backward platen rotation provides simultaneous paper ejection and dispensing.
a paper holder arranged to hold sheets of paper;
at least one rotatable drive roller disposed to operably contact said sheets of paper to be dispensed;
and a drive train for connecting said platen to said drive roller, said drive train being powered and controlled exclusively by its connection to said platen to cause no rotation of said drive roller in response to forward, paper-imprinting platen rotation, and to cause rotation of said drive roller in a forward, paper-dispensing direction in response to backward, paper-ejecting platen rotation, said drive train further arranged so that said drive roller delivers sheets of paper to a paper-loading position on said printer not before said platen ejects said printed sheet of paper;
whereby, when said platen rotates backwards to eject a sheet of paper from said printer and to cause said drive roller to move one of said sheets of paper into a paper-loading position on said printer, said backward platen rotation provides simultaneous paper ejection and dispensing.
2. The feeder in claim 1, further comprising disengaging means for disengaging, without removing, said feeder from said printer.
3. The feeder in claim 2, wherein said disengaging means disengages said feeder from said printer by eliminating operable contact between said stack of paper and said roller.
4. The feeder of claim 3, wherein a pusher plate, normally biased against said stack of paper, provides operable contact, and a manipulation of a feeder select knob fixed to a pusher rod causes said pusher rod to move said pusher plate away from said stack, thereby eliminating said contact.
5. The feeder of claim 3, wherein said releasing means comprises a pusher rod fixed to a feeder select knob, whereby said pusher rod is arranged to, in response to rotation of said feeder knob, push a pusher plate, normally biased against said stack of paper to provide operable contact, away from said stack, thereby eliminating operable contact.
6. The feeder of claim 1, further comprising attaching means for releasably attaching said paper feeder to said printer.
7. The feeder of claim 1, wherein said drive train is arranged to cause said drive roller to rotate at a velocity slower than rotational velocity of said platen, causing said drive roller to deliver sheets of paper to a paper-loading position on said printer not before said platen ejects said printed sheet of paper.
8. The feeder of claim 1, wherein said drive train is arranged to cause said feeder to dispense sheets of paper over a greater distance than a maximum length of paper to be ejected, causing said drive roller to deliver sheets of paper to a paper loading position on said printer not before said platen ejects said printed sheet of paper.
9. In a printer having sensing means for sensing leading and trailing edges of sheets of paper, control means for controlling rotation of a platen in said printer in response to said sensing, said control means responsive to sensing a trailing edge, causing said platen to rotate a predetermined amount first in a forward imprinting direction and second in a backward paper-ejecting direction, said control means further responsive to sensing a leading edge and completion of paper ejection, causing said platen to rotate in a forward imprinting direction;
a paper feeder for attachment to said printer, arranged to dispense sheets of paper, one sheet at a time, into a paper-loading position of said printer; and a drive train for connecting said paper feeder to a platen of said printer, said drive train responding solely to backward, paper-ejecting platen rotation to dispense a sheet of paper from said feeder, said drive train further arranged so that said paper feeder delivers sheets of paper to a paper-loading position on said printer not before said platen ejects said printed sheet of paper;
wherein said control means provide simultaneous paper ejection from and paper feeding into said printer solely through controlling rotation of said platen.
a paper feeder for attachment to said printer, arranged to dispense sheets of paper, one sheet at a time, into a paper-loading position of said printer; and a drive train for connecting said paper feeder to a platen of said printer, said drive train responding solely to backward, paper-ejecting platen rotation to dispense a sheet of paper from said feeder, said drive train further arranged so that said paper feeder delivers sheets of paper to a paper-loading position on said printer not before said platen ejects said printed sheet of paper;
wherein said control means provide simultaneous paper ejection from and paper feeding into said printer solely through controlling rotation of said platen.
10. In a printer having sensing means for sensing presence of a sheet of paper, a paper feeder for attachment to said printer, arranged to dispense sheets of paper, one sheet at a time, into a paper-loading position of said printer;
a drive train for connecting said paper feeder and a platen of said printer, said drive train responding solely to paper-ejecting platen rotation to dispense a sheet of paper from said feeder, said drive train further arranged so that said feeder delivers sheets of paper to a paper-loading position on said printer not before said platen ejects the printed sheet of paper;
programmed control means for controlling platen rotation in a paper-imprinting direction and in a paper-ejecting direction in response to sensing said paper presence;
wherein said programmed control means provide simultaneous paper ejection from and paper feeding into said printer solely through controlling rotation of said platen.
a drive train for connecting said paper feeder and a platen of said printer, said drive train responding solely to paper-ejecting platen rotation to dispense a sheet of paper from said feeder, said drive train further arranged so that said feeder delivers sheets of paper to a paper-loading position on said printer not before said platen ejects the printed sheet of paper;
programmed control means for controlling platen rotation in a paper-imprinting direction and in a paper-ejecting direction in response to sensing said paper presence;
wherein said programmed control means provide simultaneous paper ejection from and paper feeding into said printer solely through controlling rotation of said platen.
11. The feeder of claim 10, wherein said programmed control means are responsive to sensing no paper at start-up of said printer, causing said platen to rotate a predetermined amount in a paper-ejecting direction so as to dispense a sheet of paper from said feeder into said printer, said control means are further responsive to sensing a trailing edge, causing said platen to rotate a predetermined amount first in a paper-imprinting direction and second in a paper-ejecting direction, said control means are further responsive to sensing a leading edge and completion of paper ejection, causing said platen to rotate in a forward paper-imprinting direction, and said control means are further responsive to sensing no paper at said completion of paper ejection, causing said printer to deselect.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US48933883A | 1983-04-28 | 1983-04-28 | |
| US489,338 | 1983-04-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222262A true CA1222262A (en) | 1987-05-26 |
Family
ID=23943439
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000453001A Expired CA1222262A (en) | 1983-04-28 | 1984-04-27 | Sheet feeding apparatus |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU568632B2 (en) |
| CA (1) | CA1222262A (en) |
| GB (1) | GB2138785B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0388734B1 (en) * | 1989-03-10 | 1994-07-20 | Fujitsu Limited | Printer having a bail roller opening and closing mechanism |
| DE69024890T2 (en) * | 1989-09-18 | 1996-08-01 | Canon Kk | Recorder |
| US5988809A (en) * | 1991-09-12 | 1999-11-23 | Canon Kabushiki Kaisha | Recording apparatus with system for stacking , supplying and guiding recording media |
-
1984
- 1984-02-22 AU AU24806/84A patent/AU568632B2/en not_active Ceased
- 1984-03-16 GB GB08406945A patent/GB2138785B/en not_active Expired
- 1984-04-27 CA CA000453001A patent/CA1222262A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2138785B (en) | 1986-10-01 |
| AU2480684A (en) | 1984-11-01 |
| AU568632B2 (en) | 1988-01-07 |
| GB8406945D0 (en) | 1984-04-18 |
| GB2138785A (en) | 1984-10-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |