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GB2297315A - Removing skew from paper fed to a printer - Google Patents

Removing skew from paper fed to a printer Download PDF

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Publication number
GB2297315A
GB2297315A GB9607277A GB9607277A GB2297315A GB 2297315 A GB2297315 A GB 2297315A GB 9607277 A GB9607277 A GB 9607277A GB 9607277 A GB9607277 A GB 9607277A GB 2297315 A GB2297315 A GB 2297315A
Authority
GB
United Kingdom
Prior art keywords
paper
paper feed
feed roller
printer
roller
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.)
Granted
Application number
GB9607277A
Other versions
GB2297315B (en
GB9607277D0 (en
Inventor
Seiichi Hirano
Kenjiro Murakami
Hiroshi Ishida
Kenichi Miyazaki
Satoshi Fujioka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Epson Corp
Original Assignee
Seiko Epson Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP27056592A external-priority patent/JPH06115194A/en
Priority claimed from JP32276592A external-priority patent/JP3149894B2/en
Application filed by Seiko Epson Corp filed Critical Seiko Epson Corp
Priority claimed from GB9320721A external-priority patent/GB2271556B/en
Publication of GB9607277D0 publication Critical patent/GB9607277D0/en
Publication of GB2297315A publication Critical patent/GB2297315A/en
Application granted granted Critical
Publication of GB2297315B publication Critical patent/GB2297315B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H9/00Registering, e.g. orientating, articles; Devices therefor
    • B65H9/004Deskewing sheet by abutting against a stop, i.e. producing a buckling of the sheet
    • B65H9/006Deskewing sheet by abutting against a stop, i.e. producing a buckling of the sheet the stop being formed by forwarding means in stand-by
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0045Guides for printing material
    • B41J11/005Guides in the printing zone, e.g. guides for preventing contact of conveyed sheets with printhead
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H3/00Separating articles from piles
    • B65H3/02Separating articles from piles using friction forces between articles and separator
    • B65H3/06Rollers or like rotary separators
    • B65H3/0669Driving devices therefor

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Registering Or Overturning Sheets (AREA)

Description

PAPER SKEW REMOVAL METHOD AND PRINTER The present invention relates generally to a paper skew removal apparatus for use in a paper feeder, and, in particular, to a paper skew removal apparatus for use in a printer that will reduce the printer size and speed up print time, and a technique for removing the skew of paper in a paper feeder.
Generally, various types of paper skew removal apparatuses have been proposed.
FIGS. 16(a)-16(c) illustrate a paper skew removal apparatus described in Unexamined Japanese Patent Application No. Hei. 1-141070. The paper skew removal apparatus includes a platen 2 positioned orthogonal to an advancing direction A of a paper P fed by paired paper feed rollers 1, 1. The axis of platen 2 is parallel to the axis of each of the paired paper feed rollers 1, 1. When leading edge Pa of paper P advances and contacts platen 2, a slack loop Pb forms in paper P as shown in FIG. 16(b). The slack loop Pb absorbs a skew of the paper. Thereafter, platen 2 rotates in a clockwise direction so as to feed paper P as shown in FIG. 16(c). With platen 2 rotating in the clockwise direction, and paper P moving in the direction as indicated by arrow A, paired paper feed rollers 1, 1 rotate in the clockwise direction and a slackened part Pb', having absorbed the skew, gradually disappears.
Another paper skew removal apparatus, shown in FIGS. 17(a)-17(c), is described in Unexamined Japanese Patent Publication No. Hei. 2-62348. FIG. 21(a) shows a single long paper feed roller 3 and a discharge film 4 which interact with each other to feed paper P while pressing the paper over its full width. A pair of rollers 5, 6, positioned downstream of the combination of paper feed roller 3 and discharge film 4, are arrayed orthogonal to the advancing direction A of paper P. A leading edge Pa of paper P moves in the direction as indicated by arrow A and contacts a nip T between stationary paired rollers 5, 6. Then, as shown in FIG. 17tub), paper P is turned in the direction of an arrow B. As a result, the paper skew is removed and the paper is orientated as shown in FIG. 17(c).
The conventional paper skew removal apparatuses employing the structures described above have the following problems.
In the paper skew removal apparatus of FIG. 16, a slack loop Pb of paper P must be formed between paired paper feed roller 1, 1 and platen 2. Accordingly, a large space must be provided between paired paper feed roller 1, 1 and platen 2, and there is a long delay before paper P reaches platen 2. Formation of slack loop Pb after the paper reaches platen 2 also delays printing.
Thus, the paper skew removal apparatus of FIG. 16 has too long a paper feed time. Further, the size of the paper skew removal apparatus is large since paired paper feed roller 1, 1 and platen 2 must be positioned sufficiently away from each other in order to form the slack loop.
Furthermore, the paper skew removal apparatus described in FIG. 17 is constructed and arranged so that discharge film 4 cooperates with single long paper feed roller 3 to press the paper over its full width. Therefore, the paper skew removal apparatus has difficulty rotating paper P to remove the skew because of the pressure upon paper P over its full width.
Accordingly, it is desired to provide an improved printer which has a reduced paper feed time, a reduced size, and is capable of reliably removing a skew from the skewed paper, and a method for removing skew.
According to one aspect of the present invention there is provided a method of removing skew from a sheet of paper in a printer, comprising detecting a paper feed signal from a detecting means; moving a carriage to a paper feed position so as to engage an operating member of the carriage with an intermediate portion of a spring member and thus effect displacement of the intermediate portion of the spring member; operating the paper feed roller having a width less than the width of the paper in response to the displacement of the intermediate portion of the spring member to feed said paper along a paper feed path towards a contact means; contacting the paper and contact means to effect rotation of the paper about the paper feed roller such that any skew is removed; and moving said carriage away from said paper feed position so as to disengage said operating member from the intermediate portion of the spring member and thus stop the paper feed roller.
According to another aspect of the present invention there is provided a printer comprising: detection means for detecting a paper feed signal; a carriage with an operating member and arranged to move to a paper feed position in response to detection of a paper feed signal; a spring member arranged such that the operating member engages with, and displaces, an intermediate portion of the spring member when the carriage is in the paper feed position; a paper feed roller responsive to displacement of the intermediate portion of the spring member, for feeding a sheet of paper of at least one predetermined width, the paper feed roller having a width less than the, or the smallest, predetermined width of the paper so as to only contact a portion of the paper in the paper width direction and thus enable rotation of the paper about the portion contacted; and contact means for contacting the paper and thus applying force to the paper to effect said rotation of the paper to remove any skew, the contact means disposed in a direction essentially orthogonal to the advancing direction of the paper fed by the paper feed roller.
According to a further aspect of the present invention there is provided a printer and a sheet of paper, the printer comprising: detection means for detecting a paper feed signal; a carriage with an operating member and arranged to move to a paper feed position in response to detection of a paper feed signal; a spring member arranged such that the operating member engages with, and displaces, an intermediate portion of the spring member when the carriage is in the paper feed position; a paper feed roller responsive to displacement of the intermediate portion of the spring member, for feeding the sheet of paper, the paper feed roller having a width less than the width of the paper so as to only contact a portion of the paper in the paper width direction and thus enable rotation of the paper about the portion contacted; and contact means for contacting the paper and thus applying force to the paper to effect said rotation of the paper to remove any skew, the contact means disposed in a direction essentially orthogonal to the advancing direction of the paper fed by the paper feed roller.
Accordingly, an object of the present invention is to provide a printer incorporating an improved paper skew removal apparatus.
Another object of an embodiment of the present invention is to provide an improved paper skew removal apparatus that will not damage the paper when any skew is removed.
Still another object of the present invention is to provide a printer having a reduction in paper feed time.
A further object of the present invention is to provide a printer that is reduced in overall size.
An additional object of an embodiment of the present invention is to provide an improved paper guide to help ensure a smooth reliable paper rotation and skew removal.
Still another object of the present invention is to provide a printer having a paper skew removal apparatus in which the paper is transported immediately to the printhead after the skew of the paper is removed.
A yet further object of the present invention is to provide on improved method of operating a printer.
Still other objects and advantages of the invention will be apparent from the specification.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the invention, reference is had to the following description, taken in connection with the accompanying drawings, in which: FIGS. l(a) and l(b) are diagrammatic views showing the construction and the operation of a paper skew removal apparatus in accordance with the present invention; FIG. 2a is a cross-sectional view showing a printer incorporating a paper skew removal apparatus in accordance with an embodiment of the present invention; FIG. 2b is an enlarged fragmentary cross-sectional view of the right side of the printer of Fig. 2a.
FIG. 3 is a front elevational view of an embodiment of a printer in accordance with the present invention; FIG. 4 is a developed plan view showing a drive mechanism of the printer of FIG. 2a; FIG. 5 is an enlarged fragmentary cross-sectional view of the left side of the printer of FIG. 2a; FIG. 6 is an enlarged side elevational view of a left side frame portion of the printer of FIG. 2a and certain components mounted thereon; FIG. 7 is a detailed side elevational view of the left side frame portion of FIG. 6; FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7; FIG. 9a is a left side view of an arm used in the printer in accordance with the invention; FIG. 9b is a right side elevational view of the arm illustrated in FIG. 9a;; FIG. 9e is a top plan view of the arm illustrated in FIG. 9c; FIG. 9d is a cross-sectional view taken along lines 9d -9d of FIG. 9a; FIG. 9e is a cross-sectional view taken along lines 9e -9e of FIG. 9a; FIG. 9f is a cross-sectional view taken along lines 9f -9f of FIG. 9b; FIG. 9g is a cross-sectional view taken along line 9g -9g of FIG. 9b; FIG. 10a is a top plan view of a spring member used in the printer; FIG. 10b is a side view, partly in cross-section, of the spring member of FIG.
10a; FIG. 11 is a top plan view of a carriage used in the printer in accordance with the invention; FIG. 12 is an enlarged side elevational view of a portion of the printer in accordance with an first embodiment of the present invention; FIG. 13 is a block diagram explaining the operation of the carriage; FIG. 14 is a partially enlarged cross-sectional view of the transport section of the printer in which the paper feed rollers rotate in the paper feed direction; FIG. 15 is a partially enlarged cross-sectional view of the transport section of the printer in which the paper feed rollers rotate in a direction opposite to the paper feed direction; FIGS. l6a-16c are diagrammatic views showing the skew removal operation of a first conventional paper skew removal apparatus; and FIGS. 17a-17c are diagrammatic views showing the construction and the skew removal operation of another conventional paper skew removal apparatus.
Reference is first made to FIG. l(a) of the drawings which depicts a paper feed roller 7 formed of a single short roller. Feed roller 7 presses upon only a central portion Pc of a paper P as viewed in the paper width direction and rotates in the direction of an arrow a to feed paper P.
In this embodiment a contact portion 8 is in the form of a roller. Contact portion 8 is positioned to receive the leading edge Pa of the paper P. When the leading edge Pa of the advancing paper P contacts contact portion 8, leading edge Pa may not be parallel to the axis of contact portion 8. Therefore, a realignment operation must occur in order to place leading edge Pa and, therefore, paper P parallel to the axis of contact portion 8.
This reorientation is performed by further advancing paper P until leading edge Pa contacts contact portion 8. Essentially simultaneously, paper P will rotate in the direction of an arrow X of FIG. l(b). With the orientation of contact portion 8 perpendicular to the axis of contact portion 8, any paper skew is removed and paper P can advance correctly.
The resultant skew removal operation is reliable and operates well because feed roller 7 is a single short roller and presses only upon central part Pc of the paper as viewed in the width direction. Therefore, the paper will rotate easier about central part Pc by the operation of feed roller 7 than it would rotate in conventional skew removal apparatuses.
The paper skew removal apparatus constructed and arranged in accordance with this embodiment of the invention has the following advantages.
First, there is no need to form a slack loop between feed roller 7 and contact portion 8. Accordingly, a distance L (FIG. 1(a)) between feed roller 7 and contact portion 8 may be reduced, and no space to account for slack loop Pb of the paper is required.
Second, because of the close positions between feed roller 7 and contact portion 8, the feed time is reduced.
Lastly, the close proximity between feed roller 7 and contact portion 8 will realize an overall reduction of the paper skew removal apparatus.
It is also to be understood that contact portion 8 need not be a roller as depicted in FIGS. l(a) and 1(b), but may be formed of a plate-like member. Moreover, it is possible that any other type of contact portion may be utilized if it is orientated at a right angle to the advancing direction of the paper fed by the feed roller and is capable of contacting the leading edge of the advancing paper in order to help rotate paper P for proper feeding into the print area.
A printer incorporating the paper skew removal apparatus constructed and arranged in accordance with this embodiment will now be described.
FIG. 2 illustrates an automatic feed device generally indicated at 10. In automatic feed device 10, there is a stacker section with the bottom of the stacker section being formed of a bottom 1 la of a lower case 11 of the printer.
Sheets of paper P are fed individually by a paper feed roller 12 into an automatic paper feed path 20. Automatic feed device 10 includes a first lever 21 for detecting when a sheet of paper is fed to automatic paper feed path 20.
When paper P is fed into automatic paper feed path 20, first lever 21 rotates in a counterclockwise direction about pin 1 la as viewed in FIG. 2. Upon the rotation of first lever 21, a second lever 22 will also rotate in a counterclockwise direction as viewed in FIG. 2. Further, a third lever (not shown) will also rotate in a counterclockwise direction. After the rotation of these three levers, a paper detect switch 23 detects the paper that has been fed into automatic feed path 20.
Once the paper is detected by paper detect switch 23, any paper skew existing in paper P is removed by a skew removal process which will be described below.
Thereafter, paper P is wound around paper feed rollers 30 and moves along automatic paper feed path 20 to reach a print section 60. Prior to reaching print section 60, paper P advances by way of pinch rollers 50, which are similar in operation to paper feed rollers 30 and remain in contact therewith.
Print section 60 is located between the upper surface of an intermediate frame 110 and an ink jet head 62 mounted on a carriage 61. Carriage 61 is coordinately displaceable in a direction normal to the plane of FIG. 2. Carriage 61 is guided at one end thereof by a guide shaft 63 and at the other end thereof by an upper frame 120.
After the paper has passed through print section 60 and has had ink disposed thereon, the paper enters a paper exit path 70. Paper exit path 70 includes a transport section, generally indicated at 80, located in paper exit path 70; While paper P passes through transport section 80, paper P passes over transport rollers 81 (FIG. 3) and notched transport rollers 82 (FIG. 3). Paper P then enters an exit section, generally indicated at 90, for discharging the paper while holding the paper in a concaved state as seen in the paper discharging direction. Exit section 90 includes a push-up portion 91 located on both sides of exit portion 90. Push up portion 91 pushes up the paper at both sides thereof while a notched roller 92 pushes down the central portion of the paper.
The paper is thereafter discharged onto a discharged paper tray 100 while in the concaved state.
A detailed description will now be given to a paper skew removal apparatus constructed and arranged in accordance with this embodiment of the present invention.
As illustrated in FIGS. 4 and 5, a paper skew removal apparatus includes paper feed roller 12, a contact portion 41 located between paper feed rollers 30 and gate rollers 40 and a paper guide 42. Paper guide 42 guides paper P (indicated by a phantom line in FIG. 5) which has been fed by paper feed roller 12 to contact portion 41, located between paper feed rollers 30 and gate rollers 40. Here, paper P is forced into a curved shape and paper guide 42 supports the convex side of the curved portion of the paper.
FIG. 4 is a developed plan view illustrating a drive mechanism including many of the rollers depicted in the printer of FIG. 2. Positional relationships of the rollers and the like do not necessarily coincide with those respective components in other drawings.
Paper feed roller 12 is rotatably driven by a paper feed motor M. Motor M drives a gear G which, in turn, drives a gear 32 fastened to one end of a feed roller shaft 31. At the other end of feed roller shaft 31 is a gear 33. Gear 33 engages sun gear 13 which, in turn, engages planetary gear 14. Planetary gear 14 engages with and disengages from feed gear 15. Planetary gear 14 engages feed gear 15 only when the carriage reaches a paper feed position. Feed gear 15 is secured to one end of feed roller shaft 16. Accordingly, because paper feed roller 12 is secured to feed roller shaft 16, the rotation of feed motor M causes the rotation of paper feed roller 12.Further, when paper feed roller 12 rotates in the paper feed direction as indicated by arrow a, paper feed rollers 30 will rotate in the opposite direction as that of paper feed roller 12 (i.e., in a direction opposite to that of the paper feed direction).
Furthermore, mounted on and affixed to feed roller shaft 31 are three paper feed rollers 30. Paper feed rollers 30 are located equidistant from one another along feed roller shaft 31. Feed roller shaft 31 directly drives paper feed rollers 30. Gate rollers 40 are forced against and contact paper feed rollers 30 by means of an urging member (not shown) and any rotation of paper feed rollers 30 is directly transmitted to gate rollers 40.
FIG. 6 is an enlarged side view depicting a left side frame portion, generally indicated at 130, of the printer case. Left side frame 130 supports the left end portions of feed roller shaft 31 and feed roller shaft 16. An arm 140, located outside sun gear 13, is rotatably supported by shaft 133.
FIGS. 7 and 8 further illustrate that feed roller shaft 31 is supported by a hole 131 in left side frame portion 130 and feed roller shaft 16 is supported in a hole 132 in left side frame portion 130. Shaft 133 rotatably supports sun gear 13 and arm 140 mounted thereon.
FIGS. 9a-9g further illustrate the construction and arrangement of arm 140.
Arm 140 includes a hole 141 for rotatably receiving shaft 133, and a shaft 142 for rotatably receiving planetary gear 14 (FIG. 6). Shaft 133 rotatably receives sun gear 13. A support member 143 engages one end of a spring member 150 (see FIG. 6).
Support member 143 may take the form of a pin having a slit 143a.
FIG. 10 more clearly illustrates spring member 150. Spring member 150 is similar to a bar-like coiled spring. A lower end portion 151 of spring member 150 is coupled to support member 143 of arm 140 as shown in FIG. 6. An upper end portion 152 of spring member 150 is arranged so that it may contact a resisting portion 135 formed in a depressed portion 134 of left side frame 130. An intermediate portion 153 of spring member 150 is supported by two hold pieces 136,136 of left side frame 130.
In the normal position of spring 150, arm 140 is held in a position such that planetary gear 14 does not engage feed-in gear 15.
Further, FIGS. 9a-9g illustrate a stopper 144 formed integrally with arm 140.
Stopper 144 is inserted into an arcuate hole 137 (FIG. 7) formed in left side frame 130.
In this arrangement, arm 140 can rotate within the range of arcuate hole 137. However, arm 140 is usually forced into the position shown in FIG. 6 by the force of spring member 150.
FIG. 11 is a plan view of carriage 61. An operating member 64 is located on the left side wall of carriage 61 as depicted in FIG. 11. A distal end of operating member 64 is tapered to form a taper face 65. When carriage 61 is in a paper feed position adjacent left side frame 130, operating member 64 passes through arcuate hole 137' and a space 138 between hold pieces 136 and 136 (See FIGS. 6-8, 12), and contacts and displaces intermediate portion 153 of spring member 150 to the right as viewed in FIG.
12. This results in arm 140 rotating clockwise so that planetary gear 14 engages feed gear 15.
FIG. 12 illustrates the resulting operation when operating member 64 pushes against spring member 150 causing planetary gear 14 to engage feed gear 15. Because spring member 150 is a bar-like coiled spring, the contact between taper face 65 of the distal end of operative member 64 and intermediate portion 153 is smooth. Space 138 between and behind hold pieces 136,136 permits intermediate portion 153 of spring member 150 to deform in space 138 to the left as viewed in FIG. 12. Spring member 150 is restricted in the direction normal to left side frame 130 as viewed in FIG. 12 by hold pieces 136, 136.
In other words, the resilient force of spring member 150 is utilized for engaging planetary gear 14 with feed gear 15. Therefore, a smooth meshing operation is ensured.
Since sun gear 13 rotates in the direction to engage planetary gear 14 with feed gear 15, the meshing state of these gears is maintained unless the force applied by operating member 64 upon intermediate portion 153 or spring member 150 is removed.
The operation of carriage 61 will now be described with reference to the block diagram of FIG. 13.
When a paper feed signal is inputted from a computer (for example) to the printer, carriage 61 is moved to the paper feed position as indicated in step ST1. When carriage 61 reaches the paper feed position, operating member 64 engages and displaces intermediate portion 153 of spring member 150. Arm 140 then rotates clockwise as shown in FIG. 12 to cause the engagement of planetary gear 14 with feed gear 15.
In step ST2, a paper feed counter N (counting the number of steps defining the rotary displacement of paper feed motor M) is reset by setting counter N to zero.
In a step ST3, paper feed motor M is rotated in the reverse direction, and in a step ST4, paper feed counter N increases in increments of 1 (N = N + 1).
When paper feed motor M rotates in the reverse direction, paper feed rollers 30 and gear 33 rotate in a counterclockwise direction. This counterclockwise rotation, as shown in FIG. 12, is transmitted to feed gear 15 through sun gear 13 and planetary gear 14. Paper feed roller 12, therefore, rotates in a clockwise direction to feed paper P into the feed path, as further indicated by arrow a in FIG. 5. Paper P, in a curved state, is guided by paper guide 42 to turn first lever 21 for detecting the paper to activate paper detect switch 23 (see FIG. 2).
In step ST5, a control system (not shown) determines whether or not the paper has actually been fed using the signal detected from paper detect switch 23.
In this decision step, if it is determined that paper P has been fed, the control system rotates paper feed motor M in a reverse direction by a predetermined amount of rotation (120 steps in this example), step ST6. By reversing paper feed motor M, paper P is further moved in the forward conveying direction by the forward, clockwise rotation of paper feed roller 12. Leading edge Pa of paper P contacts contact portion 41 (FIG. 5) between gate rollers 40 and paper feed rollers 30 which are rotating in the direction opposite to paper feed direction. In this way, when a corner of paper P contacts paper feed rollers 30 and gate rollers 40, paper P cannot be fed in the forward direction since rollers 30 and 40 are rotating in the reverse direction.Therefore, paper P, being fed by paper feed roller 12, will continue to swing about central part Pc until the entire leading edge Pa is flush against paper feed rollers 30 and gate rollers 40.
Furthermore, because paper feed rollers 30 and gate rollers 40 are rotating in the opposite direction to the paper feed direction, leading edge Pa of paper P will never enter the nip between paper feed rollers 30 and gate rollers 40. This will ensure a smooth rotation of the paper and, therefore, a smooth deskewing operation.
When leading edge Pa of the paper does contact portion 41, the paper P has begun curving and follows the shape of a paper guide 42, as shown in FIG. 5. The force generated when paper P contacts contact portion 41 acts on paper P to cause the paper's rotation (in the direction of arrow X in FIG. 4) about central part Pc of paper feed roller 12. Thus, a sure paper turn, or a sure skew removal, is secured.
In step ST7, carriage 61 is positioned to the print stand-by position (where operating member 64 is disengaged from spring member 150).
This movement of the carriage causes operating member 64 to disengage from spring member 150. Spring member 150 is restored to its original shape as viewed in FIG. 6. Arm 140 rotates counterclockwise to its original position (FIG. 6), and planetary gear 14 disengages from feed gear 15.
In step ST8, paper feed motor M is then rotated in the forward direction by a predetermined number of turns (610 steps, by way of example).
By rotating paper feed motor M forward, paper feed rollers 30 also rotate in the paper conveying direction as viewed in FIG. 15. The paper is pulled into the nip of paper feed rollers 30 and pinch rollers 50, and advances past pinch rollers 50. Leading edge Pa of the paper reaches print section 60, and the print-ready state is achieved.
In step ST9, the carriage is oriented for printing. A print signal is received and a carriage motor, not shown, is driven by the print signal. Carriage 61 reciprocates.
During the reciprocative motion of the carriage, ink jet head 62 emits "dots" of ink, thereby performing the printing operation. The paper on which ink is printed is discharged through transport section 80, which includes transport rollers 81 and notched transport rollers 82. The paper then travels through exit section 90, which includes push-up means 91, which pushes the paper up along both sides thereof, and notched roller 92 which pushes the central part of the paper down. Thereafter, paper P is discharged onto discharged paper tray 100 (see generally FIG. 2).
However, if the control system determines that no paper has been fed (decision branch of ST5), the control system, by monitoring counter N, determines whether or not the number of steps of paper feed motor M, when it has been rotating in the reverse direction (the number of steps N counted in step ST4), has reached 1000 (ST10).
If the counter has reached 1000 (STl l), the control system decides that automatic feed device 10 is empty and displays a "No paper" indication in a display window (not shown).
If the counter has not reached 1000, the control system repeats the procedural sequence subsequent to step ST3.
The printer constructed, arranged and operated in accordance with the abovedescribed operation has the following advantages.
First, paper P rotates easily about paper feed roller 12. This is in part due to paper feed roller 12 being a thin, single roller. Also, paper feed roller 12 presses upon only central part Pc of the paper as viewed in the paper width direction. Paper P easily rotates about this press-contact part (central part Pc) in the direction of arrow X (FIG.
4), thereby securing a reliable removal of any paper skew.
Second, it is not necessary to form a slack loop in the paper between paper feed roller 12 and contact portion 41. Accordingly, the distance required between paper feed roller 12 and contact portion 41 is smaller than that in conventional printers. In addition, no space is required to form the slack loop as required in conventional apparatuses. The result is an overall reduction in paper feed time and printer size.
Third, between paper feed roller 12 and contact portion 41, paper guide 42 is provided to guide the paper to contact portion 41 in a curved state and will support the outside of the curved portion of the paper. The action of the paper to curve toward the outside of the curved portion is limited by paper guide 42. The force generated when paper P contacts contact portion 41 assists in causing the paper P to rotate about central part Pc of paper feed roller 12. This secures a smooth and reliable paper rotation and ensures a reliable, smooth skew removal.
Fourth, when paper feed roller 12 is rotating in the paper feed direction, paper feed rollers 30 and gate rollers 40 rotate in a direction opposite to the paper feed direction. This way leading edge Pa of the paper will not enter the nip between paper feed rollers 30 and gate rollers 40, ensuring a smooth rotation of the paper.
Fifth, since any skew is removed by bringing the paper into contact with contact portion 41 between paper feed rollers 30 and gate rollers 40, the paper can be transported immediately after the skew of the paper is removed.
Lastly, the construction of the automatic paper feeder allows for the distance between paper feed roller 12 and contact portion 41 to be shorter than that required when a separate automatic paper feeder is coupled with the printer.
The drive mechanism for transport section 80 will now be described with reference to FIGS. 4, 14 and 15. Transport section 80 includes six transport rollers 81 which are respectively aligned with six notched transport rollers 82.
Three transport rollers of the six transport rollers 81 are secured to a rotation shaft 83, and the remaining three transport rollers 81 are secured to another rotation shaft 84. Shafts 83 and 84 are supported by intermediate frame 110. Of the three paper feed rollers 30, the rollers on both sides are coupled through transmission gears, generally indicated at 85, and rotate gears 83a and 84a, which are secured to rotation shafts 83 and 84, respectively. There are two transmission gears. Each transmission gear 85 rotates each shaft 83 and 84, respectively.
Each transmission gear 85 includes a gear part 85a, which engages gear 83a or 84a, respectively, and is secured to rotation shaft 83 or 84, respectively. Each transmission gear also includes a common shaft 85c and a roller part 85b which engage feed roller 30. Both ends of the common shaft 85c are movably supported in a rectangular hole 111 formed in intermediate frame 110 (FIG. 14). With such a construction and arrangement, transmission gear 85 functions as a one-way clutch. As illustrated in FIG. 14, when paper feed rollers 30 rotate in the paper feed direction, transmission gears 85 move downward (in the engaging direction) along rectangular hole 111, and transmit the power of paper feed rollers 30 to transport rollers 81.However, as shown in FIG. 15, when paper feed rollers 30 are rotated in the direction opposite to the paper feed direction, transmission gears 85 move upward (in the escape direction) along rectangular hole 111, and do not transmit the power of paper feed rollers 30 to transport rollers 81. Thus, transport rollers 81 rotate only when paper feed rollers 30 rotate in the paper feed direction, and do not rotate when paper feed rollers 30 are rotated in the reverse direction.
As shown in FIGS. 3 and 4, two notched transport rollers 82 are secured to each end of each of the three shaft members 86. A spring, not shown, forces the center of each shaft member 86 toward transport rollers 81. Notched transport rollers 82 are driven and rotate by engagement with transport rollers 81. The diameters or the number of teeth of paper feed rollers 30, transmission gears 85, and transport rollers 81 are all selected so the peripheral speed of transport rollers 81 is about 12% faster than the peripheral speed of paper feed rollers 30. Accordingly, paper P, as shown in FIG. 14, is printed upon in print section 60 in a state that it is floating while at least essentially simultaneously being pulled by transport rollers 81 and notched transport rollers 82 thereby keeping the paper taut.
In the embodiment disclosed above, the paper skew removal apparatus is applied to a printer. However, it is understood that it may be applied in copying machines and other general printing machines such as facsimiles.
Furthermore, it is understood that while the skew removal operation in the embodiment is performed between the paper supply roller and the paper feed rollers, it may be performed between the paper supply roller and the platen roller. That is, the platen roller acts as the contact means.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the construction(s) set forth without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims (12)

1. A method of removing skew from a sheet of paper in a printer, comprising detecting a paper feed signal from a detecting means; moving a carriage to a paper feed position so as to engage an operating member of the carriage with an intermediate portion of a spring member and thus effect displacement of the intermediate portion of the spring member; operating the paper feed roller having a width less than the width of the paper in response to the displacement of the intermediate portion of the spring member to feed said paper along a paper feed path towards a contact means; contacting the paper and contact means to effect rotation of the paper about the paper feed roller such that any skew is removed; and moving said carriage away from said paper feed position so as to disengage said operating member from the intermediate portion of the spring member and thus stop the paper feed roller.
2. The method claim in claim 1, wherein the step of contacting the paper and contact means involves abutting the leading edge of said paper between a second feed roller and a gate roller, both of which constitute the contact means, whilst said second feed roller and said gate roller are rotating in a direction opposite to a paper feeding direction.
3. The method claimed in claim 1, wherein the step of contacting the paper and the contact means involves abutting the leading edge of said paper between a second feed roller and a gate roller, both of which constitute the contact means, whilst said second feed roller and said gate roller are essentially motionless.
4. A printer comprising: detection means for detecting a paper feed signal; a carriage with an operating member and arranged to move to a paper feed position in response to detection of a paper feed signal; a spring member arranged such that the operating member engages with, and displaces, an intermediate portion of the spring member when the carriage is in the paper feed position; a paper feed roller responsive to displacement of the intermediate portion of the spring member, for feeding a sheet of paper of at least one predetermined width, the paper feed roller having a width less than the, or the smallest, predetermined width of the paper so as to only contact a portion of the paper in the paper width direction and thus enable rotation of the paper about the portion contacted; and contact means for contacting the paper and thus applying force to the paper to effect said rotation of the paper to remove any skew, the contact means disposed in a direction essentially orthogonal to the advancing direction of the paper fed by the paper feed roller.
5. A printer and a sheet of paper, the printer comprising: detection means for detecting a paper feed signal; a carriage with an operating member and arranged to move to a paper feed position in response to detection of a paper feed signal; a spring member arranged such that the operating member engages with, and displaces, an intermediate portion of the spring member when the carriage is in the paper feed position; a paper feed roller responsive to displacement of the intermediate portion of the spring member, for feeding the sheet of paper, the paper feed roller having a width less than the width of the paper so as to only contact a portion of the paper in the paper width direction and thus enable rotation of the paper about the portion contacted; and contact means for contacting the paper and thus applying force to the paper to effect said rotation of the paper to remove any skew, the contact means disposed in a direction essentially orthogonal to the advancing direction of the paper fed by the paper feed roller.
6. A printer as claimed in claim 4 or 5, wherein the contact means comprises a gate roller and a further paper feed roller which engage to contact the paper.
7. A printer as claimed in claim 6, wherein the gate roller and paper feed roller are arranged such that the paper cannot be fed between them.
8. A printer as claimed in claim 7, wherein the further paper feed roller and the gate roller rotate in an opposite direction to the paper feed roller so that paper cannot be fed between the further paper feed roller and the gate roller.
9. A printer as claimed in claim 7, wherein the further paper feed roller and the gate roller are stationary so that the paper cannot be fed between them.
10. A printer as claimed in any preceding claim, further comprising an automatic paper feeder that is assembled into the printer.
11. A method of removing skew substantially as hereinbefore described with reference to figures 1 and 13.
12. A printer substantially as hereinbefore described with reference to any one or more of figures 2a to 7, 11 and 12, with or without reference to any one or more of figures la, lb, 8-10, 14 and 15.
GB9607277A 1992-10-08 1993-10-07 Paper skew removal method and printer Expired - Fee Related GB2297315B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP27056592A JPH06115194A (en) 1992-10-08 1992-10-08 Skew removing device for sheet and printer using the same
JP32276592A JP3149894B2 (en) 1992-11-06 1992-11-06 Paper feeder in printer
GB9320721A GB2271556B (en) 1992-10-08 1993-10-07 Paper skew removal apparatus and a pronter using the same

Publications (3)

Publication Number Publication Date
GB9607277D0 GB9607277D0 (en) 1996-06-12
GB2297315A true GB2297315A (en) 1996-07-31
GB2297315B GB2297315B (en) 1997-01-15

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GB9607277A Expired - Fee Related GB2297315B (en) 1992-10-08 1993-10-07 Paper skew removal method and printer

Country Status (1)

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GB (1) GB2297315B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0855284A1 (en) * 1996-11-28 1998-07-29 Agfa-Gevaert N.V. Thermal printer with sheet feeding means
US5967681A (en) * 1996-11-28 1999-10-19 Agfa-Gevaert Thermal printer with sheet feeding means
EP1369367A3 (en) * 2002-06-05 2005-02-02 Hewlett-Packard Development Company, L.P. Skew correction for a media feed mechanism

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0855284A1 (en) * 1996-11-28 1998-07-29 Agfa-Gevaert N.V. Thermal printer with sheet feeding means
US5967681A (en) * 1996-11-28 1999-10-19 Agfa-Gevaert Thermal printer with sheet feeding means
EP1369367A3 (en) * 2002-06-05 2005-02-02 Hewlett-Packard Development Company, L.P. Skew correction for a media feed mechanism

Also Published As

Publication number Publication date
GB2297315B (en) 1997-01-15
GB9607277D0 (en) 1996-06-12

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