JP2005320086A - Sheet feed device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feed device used in a stencil printing machine capable of precluding a double feed and misfeeding in the case where stacked sheets are fed one by one from the uppermost one. <P>SOLUTION: The sheet feed device is equipped with a feeder table 21 capable of elevating and sinking on which sheets are stacked, an air suction type transporting mechanism 25 installed over the feeder table 21 for transporting the uppermost sheet P1 to the transporting undersurface by attracting through air sucking, an air blowout mechanism 30 to blow out the air from the front in the sheet transporting direction toward the top of the stacked sheets P, a trailing edge guide 27 to restrict the trailing edges in the transporting direction of the stacked sheets P, and side guides 22 to restrict the sides in the sheet width direction perpendicularly intersecting the sheet transporting direction. A deterring member 23 to deter from above the two ends in the width direction of the rear half in the transporting direction of the uppermost sheet P1 is installed in the rear in the transporting direction more than the transporting mechanism 25. The sheet determent surface of the deterring member 23 should preferably be positioned in the sheet deterring position a certain distance below the transporting undersurface of the transporting mechanism 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper feeding device used for a stencil printing machine, a copier, a printer, or the like, and in particular, stacks paper, sucks the uppermost paper with an air adsorption transport mechanism, and feeds the paper to a printing unit or the like. The present invention relates to a sheet feeding device.

  Conventional paper feeding devices generally employ a method of feeding paper, pressing a paper feed roller against the topmost paper of the stacked paper, sandwiching it between the paper boards, and feeding it by friction However, since friction is used, there are problems such as a plurality of papers being sent out at the same time, feeding errors on the contrary, papers being soiled, or wrinkles on the papers.

  Conventionally, a paper feeding device as shown in FIGS. 21 and 22 has been proposed in order to reduce the double feeding of paper (Patent Document 1). The sheet feeding device shown in FIG. 21 includes a sheet feed table 201 on which sheets can be moved up and down, an air adsorption type conveyance belt mechanism 202 disposed above the sheet supply table 201, and the air adsorption type conveyance belt mechanism. An air blowing mechanism 205 that is positioned in front of the sheet conveyance direction 202 (arrow F direction) and blows out air substantially upward is provided on the lower side of the air adsorption type conveyance belt mechanism 202 as shown in FIG. A pair of presser members 206 is provided. The pressing member 206 is supported by a hinge 207 so as to be rotatable in the vertical direction, and presses both sides of the front end portion of the uppermost sheet P1 in the sheet width direction by its own weight. The air blowing mechanism 205 in FIG. 21 blows air toward the front end of the conveying surface (lower surface) of the air adsorption type conveying belt mechanism 202, and the air flows backward along the conveying surface.

In the sheet feeding device shown in FIGS. 21 and 22, the uppermost sheet P1 is adsorbed above the air adsorbing conveyance belt mechanism 202 in a state where both ends in the width direction of the front end are pressed by the pressing member 206. Therefore, the front end portion of the uppermost sheet P1 is deformed into a curved shape in which the intermediate portion in the width direction rises upward, and the front end portion of the uppermost sheet P1 deformed in this curved shape and the next sheet P2 are By feeding air from the air blowing mechanism 205, the uppermost sheet P1 and the next sheet P2 are separated to prevent double feeding.
JP-A-10-35927.

  If the front end of the uppermost sheet P1 is deformed into a curved shape and sent forward as in the sheet feeding device shown in FIGS. When the height of the sheet P1 is gradually lowered, both ends in the width direction of the curved front end of the uppermost sheet P1 collide with the air blowing mechanism 205, or one sheet can pass below the conveyance surface. In the case where the whispering plate is erected, it may collide with the whispering plate, thereby causing a feeding error. That is, as described above, even if the double feeding of sheets can be eliminated, there may occur a situation where the topmost sheet cannot be smoothly fed out.

  According to the present invention, in a paper feeding device including an air adsorption type conveyance mechanism and an air blowing mechanism, the front end of the uppermost sheet is maintained in a horizontal posture so that the paper can be smoothly fed out from the gap for separation, and the next sheet It is an object of the present invention to provide a paper feeding device that can reliably separate paper sheets of a lower level and prevent paper double feeding.

  In order to solve the above-described problems, the present invention provides a sheet feed table that can be moved up and down to stack sheets, and an air adsorption type conveyance mechanism that is arranged above the sheet feed table and adsorbs the uppermost sheet by air adsorption to the conveyance lower surface. An air blowing mechanism that blows air from the front in the paper conveyance direction toward the upper edge of the loaded paper, a rear end guide that regulates the rear edge of the loaded paper in the paper conveyance direction, and both ends in the paper width direction orthogonal to the paper conveyance direction. A sheet feeding device including a regulating side end guide is characterized in that a restraining member is arranged to deter at least both side ends in the sheet width direction on the upstream side of the air adsorption transport mechanism of the uppermost sheet from above. .

  In the present invention, the sheet restraining surface of the restraining member is preferably positioned at a sheet restraining position that is a certain distance below the lower transport surface of the air adsorption transport mechanism.

  The sheet restraining surface of the restraining member can be changed in the vertical direction between the sheet restraining position and a retracted position above the transport lower surface.

  The set height of the sheet suppression position can be changed according to various sheets.

  The sheet restraining position is a position that is a certain distance above the uppermost sheet when air is not blown out from the air blowing mechanism, and the uppermost sheet is lifted by blowing air from the air blowing mechanism. Sometimes, the uppermost sheet can be in a position where it can come into contact.

  (1) A plurality of sheets (including the uppermost sheet) at the upper end of the stacked sheets are lifted by the air from the front, and the uppermost sheet is adsorbed on the lower surface of the air adsorption type conveyance mechanism. By restraining at least both ends in the paper width direction upstream of the air adsorption transport mechanism of the paper with the restraining member, the latter half of the uppermost paper is kept in the horizontal state on the bottom surface of the transport while the restraining member restrains both ends. Can be deformed into a curved shape that swells upward and sent forward. Therefore, even if a clearance gap is formed in front of the paper feeding device, the uppermost sheet can be fed forward without colliding with the separation board, and the uppermost sheet can be reliably fed from the next sheet. Can be separated. In other words, even if the edges of the loaded paper are stuck by “burrs” etc., it is possible to reliably roll the top paper and the next paper and prevent double feeding of paper, and at the same time, misfeed due to collision etc. Can also be prevented.

  (2) If the sheet depressing surface of the deterring member is positioned at a sheet depressing position that is a certain distance below the conveying surface of the air suction type conveying mechanism, when the uppermost sheet is adsorbed to the lower surface of the conveying, The front half is deformed into a stepped shape that is higher than the rear half, so that the inclined portion between the front half and the rear half is bent in a complicated manner, and this bending causes separation of the uppermost sheet and the next sheet. It can be done more reliably.

  (3) If the sheet depressing surface of the deterring member can be changed in the vertical direction between the sheet deterring position and the retracted position above the conveying lower surface, for example, thick paper or hard bending with little possibility of double feeding When feeding difficult paper, it is possible to prevent the paper from being wrinkled or creased by retracting it to the retracted position.

  (4) If the set height can be changed according to various papers, the uppermost paper can bend appropriately for various papers in a range that does not cause excessive deformation. Can be separated from the upper sheet.

  (5) The sheet suppression position is a position that is a certain distance above the uppermost sheet when air is not blown from the air blowing mechanism, and the uppermost sheet is blown out of air by the air blowing mechanism. If the position is set so that the uppermost sheet can come into contact with the uppermost sheet, the uppermost sheet can be smoothly fed forward without the fear of pressing the uppermost sheet against the next sheet by the restraining member.

  1 to 18 show an embodiment of the present invention, which shows an example in which a paper feeding device according to the present invention is provided in a stencil printing machine, and is shown in FIG. 1 for convenience of explanation. The upstream side of the paper transport direction (arrow F) is referred to as “rear side”, the downstream side of the paper transport direction F is referred to as “front side”, and the paper width direction orthogonal to the paper transport direction is referred to as “left-right direction”. This will be described below.

[Overall structure of stencil printing machine]
FIG. 1 is a schematic side view of a stencil printing machine shown in perspective. The printing machine main body 1 is provided with a paper feeding device 2 at the rear end and a paper tray 19 at the front end.

  In the printing machine main body 1, an image forming unit 5 is provided at an approximately middle portion in the front-rear direction, a plate making device 6 is provided at the upper rear side of the image forming unit 5, and a plate discharge is provided at the upper front side of the image forming unit 5. A device 7 is provided, and a paper discharge device 3 is provided on the front side of the image forming unit of the image forming unit 5.

  The image forming unit 5 is composed of a printing plate cylinder 10 and a pressing roller 11 which are arranged opposite to each other in the vertical direction. An ink roller 12 is arranged on the inner peripheral surface of the printing plate cylinder 10. The stencil sheet N made in step 1 is attached to the plate cylinder 10.

  The plate making apparatus 6 makes a stencil sheet N with a thermal head 9 and attaches it to the plate cylinder 10 of the image forming unit 5.

  The plate discharging device 7 removes the used stencil sheet N mounted on the plate cylinder 10 and winds it up as a plate discharging roll 13.

  A pair of upper and lower timing rollers 15 are disposed in the vicinity of the rear portion of the image forming unit 5 so as to rotate at an appropriate timing in synchronization with the driving of the plate cylinder 10 so as to feed the printing paper P into the image forming unit 5. It has become.

  The paper discharge device 3 includes a conveyance belt 16 and an air suction mechanism 17, and adsorbs the printed paper P on the conveyance upper surface of the conveyance belt 16 and discharges it to the paper receiving tray 19.

[Overall structure of paper feeder]
The sheet feeding device 2 includes a sheet feeding table 21 that can be moved up and down arranged in a substantially horizontal posture, a pair of side end guides 22 disposed on both left and right sides (both ends in the sheet width direction) of the sheet feeding table 21, Adjacent to the front end of the paper feed table 21, the air adsorption type transport belt mechanism 25 disposed above the front of the paper table 21, the rear end guide 27 for regulating the rear end of the paper disposed at the rear of the paper feed table 21, and the front end of the paper feed table 21. A front end guide 28 erected so as to perform, an air blowing mechanism 30 disposed at the front upper end portion of the front end guide 28, a plurality of upper limit position sensors 31 and 32 disposed above the paper feed table 21, A restraining member 23 or the like is provided behind the air adsorbing transport belt mechanism 25 and attached to the upper end of the side end guide 22.

[Feeding mechanism of paper feed stand]
FIG. 3 shows an elevating mechanism of the paper feed table 21. Guide holes 33 and guide rails 34 that are substantially perpendicular to the side plates 29 arranged on the left and right sides of the paper feed table 21 are formed. Guide shafts 35 penetrating through the guide holes 33 are provided at both left and right ends of the guide shafts, and guide rollers 36 are supported on the guide shafts 35.

  The distal end portion of the guide shaft 35 is supported by the elevating member 37. The drive chain 38 connected to the elevating member 37 extends upward, is folded downward via the turn sprocket 40, is engaged with the lower drive sprocket 41, is further folded upward, and is coupled to the coil spring 42. . The coil spring 42 extends upward and engages with a bracket 43 provided on the side plate. The drive sprocket 41 is linked to a drive motor 46 via a pinion gear mechanism 45. That is, the drive sprocket 41 is rotated in the direction of arrow B 1 by the drive motor 46, so that the drive chain 38 is moved in the direction of arrow B 2 while being assisted by the coil spring 42, and the paper feed table 21 is raised via the elevating member 37. Thus, the controller (control device) 47 can stop the paper feed table 21 at the raised position (virtual line). The drive motor 46 is connected to the upper limit sensors 31 and 32 and the print start switch (or lift switch) 48 via the controller 47. When the paper feed base 21 is in the lowered position, the print start switch 48 is pushed. And is controlled to automatically stop and rise according to detection of paper contact and detection of paper separation by the selected upper limit sensors 31 and 32. Detailed control will be described later.

[Rear end guide]
The rear end guide 27 in FIG. 1 is formed in a substantially vertical posture, and a support base portion 27a is formed at the lower end. For example, a magnet is built in or attached to the support base portion 27a. It can be fixed at a desired longitudinal position.

[Side end guide]
FIG. 4 is a perspective view of the side end guide 22. The side end guide 22 is a beam that connects a plurality of column members 50 erected at intervals in the front-rear direction and the upper and lower ends of each column member 50. Each column member 50 includes a plurality of grooves 53 formed in the paper feed table 21 in the vertical direction and can move in the horizontal direction in the grooves 53. A driving mechanism for driving the side end guides 22 to the left and right is not particularly shown, but the side end guides 22 are moved symmetrically with respect to the central reference line O1 in the paper width direction of the paper feed table 21. Yes. In other words, the stacked paper width can be set by the central distribution method.

[Air adsorption type conveyor belt mechanism]
In FIG. 1, the air adsorbing transport belt mechanism 25 includes front and rear rotating rollers 55, a transport belt 56 wound around the both rotating rollers 55, a suction box 57 disposed in the transport belt 56, and the like. The suction box 57 is connected to a suction fan 58.

  FIG. 2 is a plan view of the air adsorption type transport belt mechanism 25. A plurality of transport belts 56 are arranged at intervals in the left-right direction, and the transport width W1 of the entire transport belt 56 is the maximum sheet width W2. That is, it is set wider than the maximum width W2 of the side end guide 22. A large number of air passage openings 59 are formed in each conveyor belt 56, and a large number of air suction slits 60 are formed on the lower surface of the suction box 57. Air is sucked through the air suction slits 60 and the openings 59. As shown in FIG. 10, the uppermost sheet P1 is attracted to the transport lower surface 56a of the transport belt 56 and transported forward.

[Air blowing mechanism]
In FIG. 1, the air blowing mechanism 30 includes an air blowing box 61 disposed in front of the upper end portion of the stacked paper P, a blower 63 connected to the air blowing box 61 via an air hose 62, and the like. Air is blown backward toward the front end of the upper end portion of the stacked paper P. As shown in FIG. 4, the front end guide 28 disposed immediately after the air blowing mechanism 30 has a plurality of notches 28 b formed in the upper end portion 28 a so that air from the air blowing box 61 passes rearward. Yes. Further, as shown in FIG. 1, the upper end of the upper end portion 28a is opposed to the conveying lower surface 56a with a predetermined separation gap D so that the upper end portion 28a of the front end guide 28 functions as a separation portion.

[Deterrence member]
In FIG. 4, a support base 66 extending in the front-rear direction is fixed to the upper ends of the left and right side end guides 22, respectively. A restraining member 23 is attached so that the vertical position can be adjusted. Each restraining member 23 is made of a metal such as stainless steel or aluminum, and the lower end of the main body portion 23a in a vertical posture is horizontally bent toward the center reference line O1, and the lower surface of the bent portion is the left and right sides of the sheet. It is a deterrent surface 23b that deters both ends from above.

  FIG. 5 is an exploded perspective view of the restraining member 23, and a pair of cylindrical guide pins 64 are fixed to the end wall 66 a of the support base 66 at regular intervals in the front-rear direction. Nuts 68 are welded on the same axis as the guide pins 64 on the back side of the end wall 66a to which the 64 is fixed. On the other hand, the main body portion 23 a of the restraining member 23 is formed with a guide long hole 71 having a downwardly inclined shape at a position corresponding to the guide pin 64. The guide elongated holes 71 are fitted into the guide pins 64, and the bolts 73 inserted into the retaining washers 72 are inserted into the guide pins 64, penetrate the end walls 66a, and are screwed into the nuts 68 to suppress the bolts 73. The member 23 is held with respect to the support base 66 so as to be movable in the length direction of the guide slot and not to fall off.

  In order to selectively fix the restraining member 23 at three vertical positions (heights), the detent ball 74, the first, second and third positioning holes 75a, 75b and 75c having different heights, the ball A detent mechanism including a pressing plate (plate spring) 76 and the like is provided. The three positioning holes 75a, 75b, and 75c are arranged in a front-down manner in parallel with the guide elongated hole 71. The detent ball 74 is inserted into a ball insertion hole 77 formed in the main body portion 23a, and is elastically pressed to the support base 66 side by one end portion of the pressing plate 76, and is selected from three positioning holes 75a, 75b, and 75c. Engaging. Of course, the inner diameter of the ball insertion hole 77 is such that the ball 74 can move in the left-right direction, while the diameters of the positioning holes 75a, 75b, and 75c are smaller than the diameter of the ball 74.

  FIG. 6 is a longitudinal sectional view taken along a plane passing through the lowest first positioning hole 75a in FIG. When the ball 74 is engaged with the lowest first position hole 75a as in the state of FIG. 6, the vertical position L1 of the lower end restraining surface 23b is lower than the conveying lower surface 56a, When the ball 74 is engaged with the second positioning hole 75b, the vertical position L2 of the lower end restraining surface 23b becomes the same height as the conveyance lower surface 56a, and the ball 74 is inserted into the highest third positioning hole 75c. When engaged, the vertical position L3 of the lower end restraining surface 23b is configured to be higher than the conveying lower surface 56a.

  In the present embodiment, the position L1 of the lower end restraining surface 23b corresponding to the first position chamfering hole 75a is set as the normal paper inhibiting position, and the position L3 of the lower end inhibiting surface 23b corresponding to the highest third position chamfering hole 75c. And the position L2 of the lower end restraining surface 23b corresponding to the intermediate second positioning hole 75b is used as the restraining position of the Western envelope.

[Upper limit sensor]
In FIG. 7, the first upper limit sensor 31 on the front side is disposed in the conveyance path of the air adsorption type conveyance belt mechanism 25, detects the height of the first half of the stacked paper P, and the second upper limit sensor on the rear side. 32 is arranged in the front-rear direction restraint range of the restraining member 23 and detects the height of the latter half of the stacked paper P. Both the upper limit sensors 31 and 32 are connected to the controller 47 as described above, and a sheet detection signal is input to the controller 47 by contacting the uppermost sheet P1 with a constant pressure as shown in FIG. The controller 47 is configured to stop the ascending motion of the paper feed table 21 after a predetermined time has elapsed (delayed) from the paper detection by the upper limit sensors 31 and 32. That is, the sheet feeding table 21 is stopped after being raised by a predetermined amount from the detection time point.

[Plain feeding and printing]
FIGS. 7 to 9 show work steps when the plain paper P is fed and printed, and FIGS. 10 to 12 show the state of the paper during feeding.

(1) Various Settings Before Paper Feeding In FIG. 7, the restraining member 23 is set in the vertical direction so that the restraining surface 23b is at the normal sheet restraining position L1 lower than the transport lower surface 56a. An interval in the vertical direction between the transport lower surface 56a and the plain paper restraining surface L1 is set to about 3 mm to 5 mm, for example. As the upper limit sensor, the second upper limit sensor 32 on the rear side is used, and the height (upper limit height) H1 of the stacked sheets when the ascending paper feed table 21 is stopped by the detection of the upper limit sensor 32 is, for example, The detection height of the upper limit sensor 32 is set so as to be approximately 20 mm below the conveyance lower surface 56a.

(2) Loading and Lifting of Normal Paper A large number of printing papers P are stacked on the paper feed tray 21 at the lowered position as shown in FIG. At this time, the front-rear guide 28 and the rear-end guide 27 restrict the position of the stacked paper P in the front-rear direction, and the left and right side-end guides 22 restrict the left-right position of the stacked paper P. Then, by pressing the print start button 48, the drive motor 46 is driven to raise the paper feed table 21, and the air blowing mechanism 30 is driven to blow air forward from the blowing box 61.

(3) Stop of Paper Feeding Base In FIG. 8, the paper feeding stand 21 stops rising after a predetermined time from the time when the second upper limit sensor 32 detects the uppermost paper P1. At this time, several plain sheets P including the uppermost sheet P1 are already lifted as shown in FIG. 9 by the air from the blow-out box 61.

(4) Adsorption In FIG. 11, when the air adsorbing conveyance belt mechanism 25 is driven, the uppermost sheet P1 is adsorbed on the conveyance lower surface 56a, but the latter half is a restraining surface 23b lower than the conveyance lower surface 56a. As a result, the left and right ends are restrained, whereby the uppermost sheet P1 is deformed into a stepped shape with a high front half when viewed from the side. FIG. 12 is a perspective view showing a state in which the uppermost sheet P1 is attracted to the conveyance belt 56. Since the width W1 of the conveyance belt 56 is wider than the width W3 of the uppermost sheet P1, the uppermost sheet P1 is illustrated. The left and right ends of the first half are maintained in a substantially complete horizontal state without sagging. On the other hand, in the latter half of the uppermost sheet P1, the right and left ends are restrained from being lifted by the restraining member 23, and air is blown from the front to the lower side of the uppermost sheet P1, so that the middle part is viewed from the rear. Is deformed into a curved shape that rises upward. Further, since the left and right side portions S1 and S1 of the intermediate portion in the front-rear direction are stepped portions, and are the change portions from the first half portion in the horizontal state to the second half portion in the curved state, the left and right side portions S1 and S1 are Is irregularly distorted, so that the uppermost sheet P1 is reliably separated from the next sheet and separated and conveyed forward. In short, as shown in FIG. 10, on the upstream side of the air suction type transport belt mechanism 25, the left and right ends of the uppermost sheet P1 are restrained by the restraining surface 23b, and the air suction type transport belt mechanism 25 as shown in FIG. As shown in FIG. 12, the transport lower surface 56a attracts the front half of the uppermost sheet P1 in a horizontal posture and supplies air from the front of the stacked sheet P to the lower side of the uppermost sheet P1. The uppermost sheet P1 is deformed stepwise and the upstream side in the transport direction is curved so as to be raised, thereby causing distortion in the left and right side parts S1 and S2 of the intermediate part and separating from the next sheet. is there.

(5) Conveyance Since the uppermost sheet P1 is completely separated from the next-order sheet as described above and is conveyed forward with the front half maintained horizontally over the entire width in the left-right direction. 11 passes through the clearance gap D between the upper end portion 28a and the conveying lower surface 56a without reaching the upper end portion 28a of the front end guide 28 in FIG. 11, and is sent to the timing roller 15 in FIG.

(6) Printing In FIG. 1, the uppermost sheet P1 sent to the timing roller 15 is sent to the image forming unit between the plate cylinder 10 and the pressing roller 11 at a predetermined timing and printed.

(7) Paper discharge The printed paper P1 is discharged to the paper receiving tray 19 through the paper discharge mechanism 3.

(8) Elevating control of paper feed base In FIG. 9, when the printing operation proceeds and the height of the stacked paper P becomes lower than the detection position of the second upper limit sensor 32 and is not detected, a command from the controller 47 is issued. When the second upper limit sensor 32 detects the sheet again, the sheet feeding table 21 stops rising after a predetermined time has passed (delayed). During the printing operation, the raising / lowering stopping operation of the sheet feeding base 21 by the detection of the second upper limit sensor 32 is repeated, and a predetermined number of plain sheets are fed and printed.

[Feeding and printing for Western-style envelopes]
The paper feeding device 2 in FIG. 1 is used not only for feeding the plain paper P as described above but also for feeding the Western envelope Pa shown in FIG. The Western-style envelope Pa has an unclosed flap 85 on its long side, is loaded with the surface (the side opposite to the side where the flap 85 is folded) up, and is conveyed in the longitudinal direction. FIG. 14 and FIG. 15 show work steps when printing the surface of a Western-style envelope, and FIGS. 16 and 17 are rear views corresponding to the steps of FIG. 14 and FIG.

(1) Various Settings Before Paper-feed Printing In FIG. 14, the restraining member 23 is set in the vertical direction so that the restraining surface 23b is at the same western envelope restraining position L2 as the transport lower surface 56a. As the upper limit sensor, the second upper limit sensor 32 on the rear side is used. As shown in FIG. 15, the detection position of the upper limit sensor 32 is set so that the height H1 of the stacking envelope Pa when the ascent of the paper feed base 21 is stopped is the same position L2 as the transport lower surface 56a. As in the case of plain paper P, the paper feed tray 21 is stopped after a certain period of time has elapsed since the detection of the envelope by the upper limit sensor 32. Is held in a state compressed by a certain amount in the vertical direction between the upper restraining surface 23b and the transport lower surface 56a and the lower paper feed table 21. In the case of a Western envelope Pa, the air blowing mechanism 30 is not used.

(2) Loading and lifting of Western envelopes Before feeding, a large number of Western envelopes Pa with the surface facing upward are stacked on the sheet feed table 21 at the lowered position as shown in FIG. FIG. 16 is a rear view at the time of loading, and each style envelope Pa is loaded with the flap 85 slightly opened obliquely downward, so that the flap side increases in volume and the flap side is inclined so that the flap side becomes higher. Become. The slope on the left and right increases as the upper Western envelope Pa is reached. After loading the envelopes, the paper feed base 21 is raised by pressing the print start button 48 in FIG. Note that the air blowing mechanism 30 is not operating.

(3) Stopping of the paper feed tray In FIG. 15, after the uppermost envelope Pa1 is detected by the second upper limit sensor 32, the paper feed tray 21 stops with a certain delay. That is, even after the uppermost envelope Pa1 comes into contact with the conveying lower surface 56a and the restraining surface 23b, the sheet feeding table 21 rises by a predetermined amount, so that the stacked envelope Pa is compressed in the vertical direction as shown in FIG. The uppermost envelope Pa1 changes from an inclined posture to a horizontal posture as viewed from the rear. Further, as shown in FIG. 15, since the restraining surface 23b and the transport lower surface 56a are maintained at the same height L2, even when viewed from the side, the uppermost western envelope Pa1 is maintained in a horizontal posture. That is, the uppermost Western-style envelope Pa1 is in a state in which the flap 85 is folded in substantially the same plane as the envelope main body, with the flap 85 almost not projecting downward from the envelope main body, and the entire envelope is horizontal along the conveyance lower surface 56a. Maintained in a state.

(4) Adsorption In the state of FIG. 15, by driving the air adsorption conveyance belt mechanism 25, the horizontal uppermost envelope Pa <b> 1 is adsorbed to the conveyance lower surface 56 a and conveyed forward by the rotation of the conveyance belt 56. As described above, the uppermost envelope Pa has a flat plate shape without a protruding portion and is fed forward while being maintained in a horizontal posture. Therefore, the uppermost envelope Pa is smoothly fed forward without being caught in the separation gap D.

(5) Conveying, printing, and discharging Since conveying, printing, and discharging are the same as in the case of the plain paper P, description thereof is omitted.

(6) Lifting Control of Feeding Table In FIG. 15, when the printing operation proceeds and the height H1 of the stacked envelope Pa becomes lower than the transport lower surface 56a and moves away from the second upper limit sensor 32, a command from the controller 47 When the paper feed base 21 is raised and the upper limit sensor 32 detects the Western envelope Pa again, the paper feed base 21 is stopped after a certain delay. During the printing operation, the raising / lowering stopping operation of the paper feed tray 21 by the detection of the second upper limit sensor 32 is repeated, and a predetermined number of Western-style envelopes Pa are printed.

[Cardboard printing]
FIG. 18 and FIG. 19 show an operation process when printing the thick paper Pb. Even in the case of plain paper as well as the thick paper Pb, it is also applied to the case where the opposite surface is printed after one-side printing in double-sided printing, or the second color is printed in two-color printing.

(1) Various settings before printing In FIG. 18, the restraining member 23 is adjusted in the vertical direction so that the restraining surface 23b is at a retracted position L3 higher than the transport lower surface 56a. That is, paper feeding is performed without using the restraining member 23. This is because it is difficult to bend the thick paper Pb, and in the case of reprinting such as double-sided printing, it is possible to prevent the papers from easily sticking to each other due to the ink between the papers. As the upper limit sensor, the second upper limit sensor 32 on the rear side is used, and the detection height of the second upper limit sensor 32 is set so that the upper limit position of the stacked cardboard Pb is, for example, about 20 mm below the conveyance lower surface. . As in the case of the plain paper, the paper feed table 21 is stopped after a certain time delay from the time when the second upper limit sensor 32 detects the paper.

(2) Stacking and lifting of thick paper As shown in FIG. 18, a large number of thick paper Pb is stacked on the paper feed tray 21 at the lowered position. After the thick paper is loaded, the print start button 48 is pressed to raise the paper feed base 21 and simultaneously operate the air blowing mechanism 30 to blow out air from the blowing box 61.

(3) Stopping of Paper Feeding Base In FIG. 19, the paper feeding stand 21 is stopped with a predetermined time delay from the time when the uppermost thick paper Pb1 is detected by the second upper limit sensor 32. At this time, several thick sheets Pb at the upper end including the uppermost thick sheet Pb are already lifted by the air from the air blowing mechanism 30.

(4) Adsorption In FIG. 19, when the air adsorbing conveyance belt mechanism 25 is driven, the uppermost thick paper Pb1 is adsorbed on the conveyance lower surface 56a, but the rigidity of the thick paper Pb is large and the air from the front. , The latter half of the uppermost thick paper Pb1 is lifted up with almost no deflection, and the entire thick paper is transported forward in a substantially horizontal posture.

(5) Transport Since the uppermost thick paper Pb1 is lifted by the air from the front, it is transported forward in a state of being completely separated from the next paper and in a substantially horizontal state. Without passing through the upper end portion 28a, it passes through the gap D for separation between the upper end of the upper end portion 28a and the conveying lower surface 56a, and is sent to the timing roller 15 in FIG.

(5) Conveyance, printing, discharging, and raising / lowering control of sheet feeding table The conveying, printing, discharging, and raising / lowering control of sheet feeding table are the same as in the case of the plain paper, and the description thereof is omitted.

[Japanese envelope printing]
The paper feeder is also used for a Japanese envelope Pc as shown in FIG. 20, and the Japanese envelope Pc has an unclosed flap 86 on its short side. When stacking the Japanese envelope Pc, the flap 86 is fully opened in a direction extending from the envelope body as shown in FIG. 20, and the flap 86 is stacked so as to be at the rear end position in the transport direction. By positioning the flap 86 in the backward direction in this way, there is no fear that the air from the front is taken into the envelope and swells compared to the Western envelope Pa, so the air blowing mechanism 30 is also used to supply the air from the front. This promotes the whispering action. When the Japanese-style envelope Pc is loaded, the glued folded part 87 on the side opposite to the flap 86 is overlapped, so that the glued folded part 87 is bulky, and the upstream side in the transport direction F is inclined upward. Therefore, it is preferable to use the first upper limit sensor 31 on the front side in FIG.

[Other Embodiments of the Invention]
(1) The restraining member is not limited to the configuration in which the restraining member is disposed only at both ends in the sheet width direction as shown in FIG. 10. For example, the restraining members at the left and right end portions are bent upward in a curved shape. It can also be set as the structure connected via.

  (2) Each of the above embodiments is an example applied to a paper feeding device of a stencil printing machine. Of course, the present invention is applied to other devices such as a digital copying machine, a sheet cutter, and an image reader. It is also possible.

  (3) The upper limit sensor can select either the first or second upper limit sensor according to the type of paper.

1 is a schematic side view of a stencil printing machine provided with a paper feeding device according to the present invention. FIG. 2 is a plan view of the sheet feeding device in FIG. 1. It is a side view of the raising / lowering mechanism of the paper feed stand of FIG. FIG. 2 is a perspective view of the sheet feeding device in FIG. 1. It is a disassembled expansion perspective view of the suppression member of FIG. It is a longitudinal cross-sectional view of the suppression member of FIG. FIG. 6 is a side view of a paper feeding device showing a preparation process when feeding plain paper. It is a side view of a paper feeding device showing a process just before feeding plain paper. It is a side view of a paper feeding device showing a paper feeding process of plain paper. FIG. 6 is a rear view of a sheet feeding device showing a sheet feeding process of plain paper. FIG. 6 is an enlarged side view of a sheet feeding device showing a sheet feeding process of plain paper. It is a perspective view which shows the state of the plain paper at the time of paper supply. It is a perspective view of a Western-style envelope. It is a side view of the paper feeder which shows the preparation process in the case of feeding a Western-style envelope. It is a side view of the paper feeder which shows the process just before paper feed of a Western-style envelope. FIG. 15 is a rear view of the paper feeding device corresponding to the preparation process of FIG. 14. FIG. 16 is a rear view of the sheet feeding device corresponding to the process immediately before sheet feeding in FIG. 15. It is a side view of a paper feeding device showing a preparation process when feeding thick paper. It is a side view of a paper feeding device showing a process immediately before feeding thick paper. It is a perspective view of a Japanese-style envelope. It is a side view of the conventional paper feeder. It is a rear view of the paper feeder of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer main body 2 Paper feeder 22 Side edge guide 23 Suppression member 23b Suppression surface 25 Air adsorption type conveyance belt mechanism 27 Rear end guide 28 Front end guide 30 Air blowing mechanism 31 First upper limit sensor 32 Second upper limit sensor 47 Controller 56 Conveying belt 56a Conveying lower surface 57 Suction box 61 Air blowing box P Paper Pa Western envelope Pb Thick paper

Claims (5)

A paper feed base that can be moved up and down to stack paper, an air adsorption type transport mechanism that is located above the paper feed base and sucks air on the lower surface of the transport, and transports the paper toward the upper end of the stack. Paper feed including an air blowing mechanism that blows air from the front in the conveyance direction, a rear end guide that regulates the rear end of the stacked paper in the paper conveyance direction, and a side end guide that regulates both ends in the paper width direction perpendicular to the paper conveyance direction In the device
A sheet feeding device comprising: a restraining member configured to depress at least both ends of the uppermost sheet on the upstream side of the air adsorption transport mechanism from the upper side in the sheet width direction.   The sheet feeding device according to claim 1, wherein the sheet restraining surface of the restraining member is positioned at a sheet restraining position that is a certain distance below the lower transport surface of the air adsorption transport mechanism.   The sheet feeding device according to claim 2, wherein the sheet depressing surface of the deterring member is changeable in a vertical direction between the sheet deterring position and a retracted position above the transport lower surface.   The sheet feeding device according to claim 2, wherein a set height of the sheet suppression position can be changed according to various sheets. The sheet restraining position is a position that is a certain distance above the uppermost sheet when air is not blown out from the air blowing mechanism, and air is blown out from the air blowing mechanism to lift the uppermost sheet. The sheet feeding device according to any one of claims 2 to 4, wherein the sheet feeding position is a position where the uppermost sheet can sometimes come into contact.

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