JP2012162340A - Double-sided printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform resist operation in a switch-back carrying passage before printing the other face of an envelope.SOLUTION: In this double-sided printer 1, the envelope F is fed by a paper feeding part 20 in a state that a rear end Fe on a side opposite to a flap Fd formed at a tip Fc of the envelope F is set to a leading portion in a sheet feed direction, and the rear end Fe of the envelope F fed before one face of the envelope F is printed is made to temporarily abut on a first resist mechanism 42 installed before a printing part 60 so as to correct the skew of the envelope F. Then, after one face is printed by the printing part 60, the surface and back face of the envelope F are reversed within a circulation carrying passage JR, and before the other face of the envelope F is printed, the rear end Fe of the reversed envelope F is made to abut on an envelope abutment member 91 within a second resist mechanism 90 installed in the switch-back carrying passage so as to correct the skew of the envelope F. Then, the envelope F is switched back so that the flap Fd side of the envelope F is set to a leading position, and the envelope F is carried toward the printing part 60 via the first resist mechanism 42 again.

Description

  The present invention is configured to reliably correct skew of an envelope before printing both sides (one side and the other side) of an envelope when printing images or characters on both sides of a sheet or envelope. The present invention relates to a duplex printing apparatus.

  Generally, in order to reduce the amount of paper used from the viewpoint of environmental problems, a double-sided printing apparatus that can print both sides of a paper or an envelope is often used.

  In this type of double-sided printing device, the printing section is configured with a structure according to the inkjet printing method, stencil printing method, laser printing method, thermal transfer printing method, etc. In order to print, a transport mechanism of a printing apparatus to which an ink jet printing method is applied has been proposed (for example, see Patent Document 1).

  In the transport mechanism of the printing apparatus disclosed in Patent Literature 1, although not shown here, the transport path of the printing apparatus includes a normal path from a paper feed path for supplying a recording medium to a paper discharge path, and a normal path. And a reversing path that reverses the front and back of the recording medium by reciprocating the recording medium back and forth by reversing the transport mechanism forward and backward. ing.

  At this time, in the above-described printing apparatus, paper is used as a recording medium, but double-sided printing on an envelope is demanded by applying this printing apparatus.

  On the other hand, when an envelope is used, there are an image forming apparatus that can print on both sides of a sheet or an envelope, a control method for the image forming apparatus, a sheet member detection method, and a feeding device (for example, see Patent Document 2).

  In the image forming apparatus, the image forming apparatus control method, the sheet member detection method, and the feeding apparatus disclosed in Patent Document 2, although illustration is omitted here, an image is transferred while transporting paper into the apparatus main body. An image forming unit for forming and a sub-scanning conveying unit for conveying the sheet, and the like are used to feed sheets one by one from a sheet feeding unit including a sheet feeding cassette provided at the bottom of the apparatus body. While the paper is transported at a position facing the image forming unit by the scanning transport unit, droplets are ejected onto the paper by the image forming unit to form (print) a desired image, and then discharged in the case of single-sided printing. In the case of duplex printing, the paper is discharged from the middle of the paper discharge transport section to the duplex unit provided at the bottom of the printer body. Switchback for paper The go, and is configured to again discharge onto the discharge tray after forming an image on both sides by feeding the sub-scanning conveying section.

  At this time, when an envelope is used separately from the paper, whether or not the flap portion formed at the front end portion of the envelope is open is set near the registration roller pair installed between the paper feeding portion and the image forming portion. The thickness of the sheet-like member fed is detected by the provided thickness detection sensor to detect a change in the thickness of the sheet-like member, and the fed sheet-like member is an envelope or other than an envelope Or by detecting whether the flap is open or closed when it is an envelope, gap adjustment, print mode change, pre-print part pause, print start position transition, conveyance error detection change, print regulation for the flap part, It is described that control according to the state of the envelope and the flap portion is performed with respect to the change of the discharge conveyance path.

JP 2010-111508 A JP 2007-152644 A

  By the way, in the case where the technical idea of the image forming apparatus disclosed in Patent Document 2 described above is employed in order to print the image and characters on both sides of the envelope by applying the printing apparatus disclosed in Patent Document 1 described above. In addition, it is possible to detect whether the flap portion is open or closed with respect to the envelope fed by a thickness detection sensor provided in the vicinity of a pair of registration rollers installed between the paper feeding portion and the image forming portion. However, in the image forming apparatus disclosed in Patent Document 2 described above, before the envelope is conveyed to the image forming unit, the leading end in the conveyance direction of the envelope is abutted against the pair of temporarily stopped registration rollers. The registration operation is performed so as to correct the skew of the envelope on both sides.

  However, when printing on one side of the envelope, the leading edge in the envelope transport direction is the rear end side opposite to the flap portion, and the envelope is transported when the other side of the envelope is printed after switching back. Since the top of the direction is the flap part side, if the flap part is open when printing on both sides of the envelope, the registration operation is performed by the same pair of registration rollers on one side and the other side of the envelope. As a result, a malfunction occurs in the registration operation to the flap portion of the envelope for the following reason.

  That is, when the leading edge in the envelope transport direction is on the rear end side opposite to the flap portion side, the paper is thick because there are three sheets of paper, but the leading edge in the envelope transport direction is on the flap portion side. In this case, since the thickness of the paper is one sheet, the flap portion side is stiff and may be bent, so that the registration operation by the registration roller pair on the flap portion side becomes unstable.

  Therefore, if the technical idea of the image forming apparatus disclosed in Patent Document 2 is adopted as it is in the double-sided printing apparatus disclosed in Patent Document 1, the registration operation performed before printing the other surface of the envelope. May cause problems.

  Therefore, when using an envelope, set the rear end opposite to the flap formed at the front end of the envelope to the top in the paper feed direction, feed the envelope with the paper feed unit, Before printing the surface, correct the skew of the envelope by the first resist mechanism installed upstream of the printing unit in the transport direction, and print the front and back of the envelope after printing one side of the envelope at the printing unit. By the envelope abutting member in the second resist mechanism provided in the switchback conveyance path that is reversed in the reverse conveyance path and further connected to the reverse conveyance path before printing the other side of the envelope after the reverse. Provided is a double-sided printing apparatus configured to correct the skew of an envelope.

The present invention has been made in view of the above problems, and the invention according to claim 1 is a double-sided printing apparatus for printing images and characters on both sides of an envelope.
Paper feeding that feeds the envelopes stacked one by one on the paper feed tray by setting the rear end on the opposite side of the flap formed at the leading edge of the envelope as the head in the paper feeding direction. And
A printing unit for selectively printing one side and the other side of the envelope;
It is installed upstream of the printing unit in the transport direction, and temporarily abuts the rear end of the envelope fed by the paper feeding unit before printing one surface of the envelope. A first registration mechanism that corrects the skew of the envelope and that conveys the envelope to the printing unit when printing one side of the envelope that has been skew-corrected and when printing the other side of the envelope And
A reversing conveyance path for reversing and conveying the other surface to the printing unit with respect to the envelope on which the one surface is printed by the printing unit;
The envelope which is connected to the reversing conveyance path and is reversed is switched back so that the flap side of the envelope is at the head, and the envelope is conveyed again toward the printing unit via the first registration mechanism unit. A switchback transport path to
An envelope abutting member is installed in the switchback conveying path, and a second registration mechanism that corrects skew of the envelope by abutting a rear end portion of the envelope against the envelope abutting member;
A paper discharge unit for discharging the printed envelope;
A control unit for controlling each unit,
The control unit controls the first registration mechanism unit so that the skew correction is not performed on the flap portion of the envelope that is switched back after the skew correction is performed by the second registration mechanism unit. This is a double-sided printing apparatus.

The invention according to claim 2 is the double-sided printing apparatus according to claim 1,
The second registration mechanism part is:
Gripping means for temporarily gripping the envelope when the rear end of the envelope is abutted against the envelope abutting member;
It is installed in the switchback conveyance path so as to face the envelope abutting member at a distance, and the rear end of the envelope reversed in the reversal conveyance path is rotated in a direction to abut against the envelope abutting member. And a pair of rollers that reversely reverse the envelope after correcting the skew by the envelope abutting member and switch the envelope back toward the printing side via the first registration mechanism portion, and
A nip releasing mechanism for temporarily releasing a nip to the envelope with respect to the roller pair after abutting a rear end portion of the envelope against the envelope abutting member;
A double-sided printing apparatus.

The invention according to claim 3 is the double-sided printing apparatus according to claim 1 or 2,
The second registration mechanism part is:
The double-sided printing apparatus includes a moving unit that moves the envelope abutting member to a predetermined position according to the length of the envelope along the switchback conveyance path.

  According to the double-sided printing device of claim 1, after setting the rear end portion opposite to the flap portion formed at the front end portion of the envelope to the top in the paper feeding direction, the envelope is fed by the paper feeding portion, Before printing one side of the envelope, the rear end of the fed envelope is temporarily abutted against the first registration mechanism to correct the skew of the envelope, and then the one side of the envelope is A second resist in which the front and back sides of the envelope are reversed in the reversing conveyance path after printing in the printing unit, and the rear end of the envelope that has been reversed before printing the other side of the envelope is provided in the switchback conveyance path The envelope is abutted against the envelope abutting member in the mechanism portion to correct the skew of the envelope, and then the envelope is switched back and the envelope is printed again through the first registration mechanism portion with the flap side of the envelope as the head. The controller corrects the skew by the second registration mechanism when transporting toward the part. Since the first registration mechanism unit is controlled so that the skew correction is not performed on the flap portion of the envelope switched back to the envelope, the envelope abutment in the second registration mechanism unit provided in the switchback conveyance path Envelope skew can be reliably corrected before the other side is printed by the member, and the flap portion of the envelope that switches back to the printing section through the first registration mechanism section can be corrected. Since it is not necessary to perform the registration operation by the single registration mechanism unit, the envelope can be reliably conveyed toward the printing unit without damaging the flap portion of the envelope.

  According to the double-sided printing apparatus of claim 2, the second registration mechanism section includes a gripping means for temporarily gripping the envelope when the rear end portion of the envelope is abutted against the envelope abutting member, and a switchback. A pair of rollers placed opposite to the envelope abutting member in the conveying path and facing the envelope abutting member after the rear end of the envelope is abutted against the envelope abutting member, and then the nip to the envelope is temporarily set against the roller pair. And a nip release mechanism that releases the nip to the envelope. After abutting the rear end of the envelope against the envelope abutting member, the nip to the envelope by the roller pair is temporarily released while the envelope is held by the gripping means. By doing so, the skew of the envelope can be reliably corrected before the other side of the envelope is printed.

  According to the double-sided printing apparatus of claim 3, the second registration mechanism section includes a moving means for moving the envelope abutting member to a predetermined position according to the length of the envelope along the switchback conveyance path. Therefore, it is possible to cope with envelopes having all kinds of lengths at the time of skew correction before printing the other side of the envelope after inverting the front and back.

(A), (b) is the top view and side view for demonstrating the envelope used for the double-sided printing apparatus of the Example which concerns on this invention. In the envelope shown in FIG. 1, (a) shows the feeding direction to the printing unit when printing one side (Fa side) of the envelope, and (b) shows the other side (Fb side) of the envelope. It is the figure which showed the conveyance direction to the printing part when printing. 1 is an overall configuration diagram illustrating an overall configuration of a double-sided printing apparatus according to an embodiment of the present invention. It is the figure which expanded and showed the control part shown in FIG. (A), (b) is the block diagram and perspective view which expanded and showed the 2nd registration mechanism part provided in the switchback conveyance path shown in FIG. FIG. 6 is a diagram for explaining a registration operation by the second registration mechanism shown in FIG. 5.

  Hereinafter, an embodiment of a duplex printing apparatus according to the present invention will be described in detail with reference to FIGS.

  In the double-sided printing apparatus according to the present invention, when printing on both sides of a sheet or an envelope, the printing unit is configured in a structural form corresponding to an inkjet printing method, a stencil printing method, a laser printing method, a thermal transfer printing method, or the like. In the following embodiments, a case will be described in which, for example, an inkjet printing method is applied to a printing unit, and images and characters are printed on both sides of an envelope by the printing unit.

  Before explaining the duplex printing apparatus 1 of the embodiment according to the present invention shown in FIG. 3, an envelope used in the duplex printing apparatus 1 will be briefly described with reference to FIGS.

  As shown in FIGS. 1A and 1B, the envelope F is formed in a rectangular shape having a length dimension in the transport direction of Lmm and a width dimension orthogonal to the transport direction of Bmm.

  The above-described rectangular envelope F is formed into a bag shape by superimposing the cover Fa and the back paper Fb, and a flap portion for sealing after enclosing a letter or the like on the front end Fc side of the envelope F Fd is formed, and the rear end portion Fe side opposite to the flap portion Fd side is glued to the backing paper Fb with the glue margin Ff.

  Accordingly, the flap portion Fd formed on the front end Fc side of the envelope F has a thickness equivalent to one sheet of paper, and is weak and easily broken, but the thickness on the rear end Fe side opposite to the flap Fd side is three sheets of paper. Since it becomes a minute, rigidity is strong.

  Then, as shown in FIG. 2 (a), for example, a plurality of envelopes F are stacked on a paper feed tray (to be described later) with the envelope Fa facing up, and the envelopes F are fed one by one. When printing one surface (Fa surface), the rear end portion Fe having high rigidity is set at the head in the paper feeding direction and conveyed to the printing unit.

  On the other hand, as shown in FIG. 2B, after printing one surface (Fa surface) of the envelope F, the front and back of the envelope F are reversed and switched back to print the other surface (Fb surface). In some cases, the flap portion Fd having a low waist is set at the head in the transport direction in which the flap portion Fd is transported to the printing unit.

  Even when one side of the envelope F is set to the cover Fb side and the other side is set to the cover Fa side, the leading end in the transport direction at the time of feeding is set to the rear end Fe side of the envelope F. .

  Here, the overall configuration of the double-sided printing apparatus 1 according to the embodiment of the present invention will be described with reference to FIG.

  In the double-sided printing apparatus 1 according to the above-described embodiment, the operation panel unit 10 that operates the entire apparatus and the paper feed roller 23 feeds the envelopes F stacked on the paper feed tray 21 one by one. After the envelope F, which is installed upstream of the printing unit 60 and the printing unit 60 to be described below, and is fed by the paper feeding unit 20 before printing one surface (Fa surface) of the envelope F The end Fe is temporarily abutted to correct the skew of the envelope F, and when printing one surface (Fa surface) of the envelope F corrected for skew, and the other surface (Fb surface) of the envelope F The first registration mechanism unit 42 that conveys the envelope F to the printing unit 60 when printing the image, and the first registration mechanism unit 42 that is installed downstream of the first registration mechanism unit 42 and is conveyed through the first registration mechanism unit 42. The envelope F is transported downstream from the printing unit 60 and the printing unit 60 described below. A belt platen unit 50 and an envelope which is disposed downstream of the first resist mechanism unit 42 and has at least one inkjet head 61 for discharging the ink IK and is conveyed via the first resist mechanism unit 42. A printing unit 60 that selectively prints images and characters on one side (Fa side) and the other side (Fb side) of F, and an envelope F on which one side (Fa side) is printed by the printing unit 60 On the other hand, a reverse conveyance path (hereinafter referred to as a circulation conveyance path) JR installed in a loop so as to be reversed so that the other surface (Fb surface) faces the printing unit 60, and a circulation conveyance path JR. , A discharge conveyance path HR that is branched and connected to one side from the downstream side, a discharge section 80 that discharges the printed envelope F printed by the printing section 60, and a circulation transfer path JR. Is branched and connected to the other side from the downstream to the circulation conveyance path J The switch-back conveyance path SR for switching the envelope F whose front and back are reversed and turning the flap portion Fd side of the envelope F toward the head in the conveyance direction, and the length of the envelope F along the switch-back conveyance path SR Accordingly, the second end of the envelope F, which is installed so as to be movable to a predetermined position and has been inverted, abuts against the envelope abutting member 91 provided in the switchback transport path SR, and performs a registration operation. By including a resist mechanism unit 90, a control unit 100 that controls each unit, and a power supply unit 110 that supplies power to each unit, an inkjet printing method is applied.

  At this time, in order to convey the envelope F at a constant speed along the constant speed section in the circulation transport path JR, a plurality of roller pairs R1 that are rotationally driven at a constant transport speed, and a variable speed downstream of the constant speed section. A plurality of roller pairs R2 that are rotationally driven at a speed higher than a certain conveyance speed according to the length of the envelope F along the section are installed, and along the discharge conveyance path HR and the switchback conveyance path SR. Depending on the length of the envelope F, a plurality of roller pairs R3 and R4 that are rotationally driven at a speed higher than a certain conveying speed are provided.

  Here, the parts of the duplex printing apparatus 1 according to the embodiment will be specifically described in order. The casing 2 forming the appearance of the duplex printing apparatus 1 is formed in a box shape.

  First, the above-mentioned operation panel unit 10 is installed on the upper surface 2a of the housing 2, and although detailed illustration is omitted here, a single-sided / double-sided printing key for selecting single-sided printing or double-sided printing, an envelope printing key , Paper printing key, start key, stop key, numeric keypad for entering numbers, number-of-printing-setting key for setting the number of copies to be printed, alarm display for warning of jam occurrence and various failures, etc. ing.

  Next, the above-described paper feed unit 20 includes a paper feed base 21 on which a plurality of envelopes F are stacked, and is provided on the outside of the paper feed guide side plate 2b1 provided vertically by a motor 22 with an encoder at a lower portion on the left side surface of the housing 2. Are arranged so as to be movable up and down.

  At this time, although the detailed illustration here is omitted, the paper feed table 21 can load paper (not shown) such as plain paper, thick paper, thin paper, matte paper in addition to the envelope F. In addition, a sheet presence / absence detection sensor for detecting the presence / absence of the envelope F and the sheet, a sheet length detection unit for detecting the length of the envelope F and the sheet, a pair of side fences for regulating the width direction of the envelope F and the sheet, and the like. Although provided, only one type of envelope F or sheets can be stacked on the sheet feed table 21 without being mixed, and in the first embodiment, a plurality of envelopes F are stacked.

  When the envelope F is stacked on the paper feed tray 21, for example, the envelope F is set with the cover Fa facing up and the rear end Fe having a high rigidity at the top in the paper feeding direction. F is fed toward a printing unit 60 described later, and the user presses an envelope printing key or a paper printing key provided on the operation panel unit 10 according to the envelope F or the paper loaded on the paper feed tray 21. It is designed to operate selectively.

  It should be noted that since the user can visually confirm when the flap Fd, which is weak in the envelope F, is loaded on the sheet feeding table 21 with the leading edge in the sheet feeding direction, the rear end portion Fe side of the envelope F is leading. However, in order to detect automatically rather than visually, the technical idea of Patent Document 2 described above is adopted, and the downstream side of the roller 24 and the friction plate 25 of the paper feeding unit 20 is adopted. If the thickness detection sensor is installed in the flap F, the flap portion Fd of the envelope F can be detected at the time of paper feeding.

  A paper feed roller 23 is rotatably provided above the paper feed table 21, and the paper feed roller 23 moves up along the paper feed guide side plate 2 b 1 of the housing 2. Thus, the uppermost envelope F is brought into contact with the uppermost envelope F and fed one by one.

  Further, the uppermost envelope F fed by the paper feed roller 23 is separated one by one while being nipped and conveyed between the separating roller 24 and the friction plate 25 provided downstream of the paper feed roller 23 in the conveyance direction. Thus, the double feed is prevented, and thereafter, the uppermost envelope F is conveyed to the circulating conveyance path JR provided in a loop shape downstream of the sheet feeding conveyance path KR.

  At this time, the paper feeding roller 23 and the roller 24 provided in the paper feeding unit 20 are each driven to rotate counterclockwise at a constant conveyance speed by a motor 26 with an encoder via a gear train (not shown). The envelope F is transported at a predetermined transport speed at this constant transport speed.

  In addition, a first registration mechanism unit 42 is installed upstream of the circulation conveyance path JR and in front of the printing unit 60, and the first registration mechanism unit 42 is fed by the sheet feeding unit 20. The function of correcting the skew of the envelope F before printing one surface (Fa surface) of the envelope F, and the time of printing one surface (Fa surface) of the envelope F subjected to skew correction and the other of the envelope F And the function of conveying the envelope F to the printing unit 60 when printing the surface (Fb surface).

  The first registration mechanism 42 described above uses a registration roller pair 42 in which a driving roller that is rotationally driven by a motor 43 with an encoder and a driven roller that is driven by the driving roller are used as a pair. 42 can be temporarily stopped and rotated for a predetermined time.

  In this embodiment, the registration roller pair 42 is used as the first registration mechanism 42. However, any structure may be used as long as it has the above-described functions. Further, it is also possible to adopt a configuration with a registration roller that is driven to rotate and a conveyance guide plate with which the registration roller abuts.

  In this embodiment, the rear end portion Fe of the envelope F fed by the paper feeding unit 20 temporarily abuts against a first registration mechanism unit (hereinafter referred to as a registration roller pair) 42 whose temporary rotation is stopped. When the registration sensor 41 installed upstream of the registration roller pair 42 detects the rear end portion Fe of the envelope F being fed, the feeding roller 23 and the separating roller 24 are further moved for a certain period of time. When rotated, a predetermined amount of deflection T is caused by the rear end portion Fe of the envelope F as shown by a two-dot chain line on the upstream side of the temporarily stopped registration roller pair 42, and the rear end position of the envelope F is caused by this deflection T. Since the registration roller pair 42 is aligned, the registration operation for correcting the skew of the envelope F is performed by the registration roller pair 42 before printing one surface (Fa surface) of the envelope F.

  The operation of the registration roller pair 42 when printing the other surface (Fb surface) of the envelope F will be described in detail later.

  A registration sensor 41 is installed on the upstream side of the registration roller pair 42, and a first top edge sensor 44 is installed on the downstream side. Both sensors 41 and 44 are envelopes using a light transmission type photosensor. While detecting the passage state of F, the first top edge sensor 44 also has a function of controlling the ejection start of the ink IK with respect to the ink jet head 61 provided in the printing unit 60.

  Then, after the amount of deflection T generated at the rear end portion Fe of the envelope F reaches a predetermined amount, the motor 43 with an encoder rotates the registration roller pair 42 in accordance with the conveyance speed, and the envelope F is a belt described below. It is conveyed toward the platen unit 50 and the printing unit 60.

  Further, in the circulation conveyance path JR, downstream of the first top edge sensor 44 in the conveyance direction, the light reflection type second top edge sensor 45, the belt platen unit 50, and the printing opposed to the belt platen unit 50 are performed. The unit 60 is installed.

  Since the second top edge sensor 45 is provided above the belt platen unit 50 and upstream of the printing unit 60, a light-reflective photosensor is used. This second top edge sensor 45 has a function of controlling the start of ejection of the ink IK to the inkjet head 61 in cooperation with the first top edge sensor 44 provided on the upstream side.

  At this time, when the rear end portion Fe of the fed envelope F passes through the first and second top edge sensors 44 and 45, an encoder from an encoder-equipped motor 54 provided in a belt platen portion 50 described later. Counting is started by the first and second counters 100d and 100e (FIG. 4) provided in the controller 100, and the number of encoder pulses counted here is preset for each inkjet head 61 of each color. The discharge of the ink IK of each color is started when the number reaches the number, but the second top edge sensor 45 installed downstream of the first top edge sensor 44 mainly performs ink discharge control, The first top edge sensor 44 is prepared as a backup when the ink discharge control by the second top edge sensor 45 becomes impossible.

  The reason for this is that the second top edge sensor 45 is installed above the endless belt platen 52 in the belt platen unit 50 and at a position close to the inkjet head 61, and the envelope F is printed at the endless belt platen 52 during printing. Since the air is sucked upward and is conveyed at a constant speed, more accurate ink ejection timing is obtained when the rear end portion Fe of the envelope F is detected by the second top edge sensor 45. The second top edge sensor 45 is mainly used.

  However, since the second top edge sensor 45 is installed above the endless belt platen 52, a light-reflective photosensor must be used, and therefore the reflection between the endless belt platen 52 and the envelope F (or paper). When the rate is close, for example, when the black envelope F (or paper) is mounted on the black endless belt platen 52, the envelope F (or paper) may not be detected. In this case, a light-transmissive photosensor Since the envelope F (or paper) can be reliably detected by the first top edge sensor 44 using the sensor, the first top edge sensor 44 is switched to.

  Further, the belt platen portion 50 described above has a plurality of air suction holes (not shown) in the box 51 and a belt-like endless belt platen 52 is fixed by a driven pulley 53 and a motor 54 with an encoder. An endless pulley 56 is provided between the drive pulley 55 and the drive pulley 55 that is rotationally driven at the conveyance speed. Further, the paper pressing rollers 57 and 58 are brought into contact with the driven pulley 53 and the drive pulley 55 to thereby endlessly move. At least one or more envelopes F conveyed on the belt platen 52 are conveyed toward the printing unit 60 and a later-described paper discharge unit 80 while air is sucked by an air suction unit 59 installed inside the endless belt platen 52. Yes.

  At this time, the belt platen unit 50 moves up and down (not shown) so that an interval (gap) between the endless belt platen 52 and an inkjet head 61 (to be described later) can be adjusted according to the envelope F and paper (not shown). When the user operates the envelope printing key provided on the operation panel unit 10, the gap is set to 3 mm, for example, while the paper printing key is operated. The gap is set to 1.5 mm, for example.

  The printing unit 60 is disposed above the belt platen unit 50 so as to be opposed to the belt platen unit 50 with a slight space therebetween, and is positioned at a substantially central portion in the housing 2.

  In this printing unit 60, a plurality of inkjet heads 61 corresponding to a plurality of colors of ink IK are used for C (cyan), K (black), M (magenta) from the upstream side to the downstream side in the conveyance direction of the envelope F. ) And Y (yellow), and a paper pressing roller 62 for pressing the envelope F onto the endless belt platen 52 is provided between the inkjet heads 61.

  In the first embodiment, an example in which four inkjet heads 61 are installed corresponding to four colors (CKMY) of ink IK will be described. For example, when printing only characters, only one color (K) is used. Therefore, it is sufficient that at least one inkjet head 61 is installed.

  Here, although not shown in detail, the inkjet head 61 for each color is configured in a line type, and a head block in which a plurality of nozzles are arranged in a main scanning direction perpendicular to the paper surface is main scanning. A plurality of lines are arranged along one line along the direction, and are divided into a total of two lines in the sub-scanning direction orthogonal to the main scanning direction. They are staggered so as to overlap each other.

  Then, while the envelope F is fixed on the endless belt platen 52 by air suction, the print data D (4) is printed by the four inkjet heads 61 while the envelope F is conveyed in the sub-scanning direction (arrow direction) by the rotation of the endless belt platen 52. A color image is printed based on FIG.

  In addition, a light reflection type first branch sensor 71 and a first flipper 72 are provided in the circulation conveyance path JR immediately after the downstream of the belt platen unit 50 and the printing unit 60, and printing has been completed by the first branch sensor 71. When the rear end portion Fe of the envelope F is detected, the first flipper 72 is turned upward to branch the printed envelope F so as to be conveyed in a loop shape. When it is desired to immediately discharge the envelope F, the envelope F is moved to the casing 2 by the roller pair R0 via the branch path BR that is horizontally connected to the belt platen unit 50 by rotating the first flipper 72 horizontally. Can be discharged to a first discharge tray 81 of a discharge section 80 that is detachably provided on the right side surface 2c side. Normally, a printed envelope F is discharged to a discharge conveyance path HR described later. To the second paper output tray 82 There.

  The circulation conveyance path JR is provided with a light-reflective second branch sensor 73 at a straight line portion after being curved in a curved shape downstream of the first branch sensor 71 and the first flipper 72, and A discharge conveyance path HR and a switchback conveyance path SR are branched and connected to one and the other via a second flipper 74 downstream of the two-branch sensor 73.

  The printed envelope F printed on one surface (Fa surface) by the printing unit 60 is inverted when passing through the curved portion of the circulation conveyance path JR, and the other surface (Fb surface) is described later. When the envelope F is detected by the second branch sensor 73 and the second flipper 74 is rotated upward when the envelope F is detected by the second branch sensor 73, the printed envelope F is removed. After detecting discharge by the light reflection type discharge sensor 75 with respect to the printed envelope F guided to the discharge conveyance path HR and conveyed by the roller pair R3 provided along the discharge conveyance path HR. The paper is discharged to the second paper discharge tray 82 of the paper discharge unit 80 provided to be inclined near the upper portion 2d on the left side surface of the housing 2.

  On the other hand, when printing is performed on the other surface (Fb surface) of the envelope F, the envelope F printed on one side is provided along the switchback transport path SR by rotating the second flipper 74 downward. The switchback sensor 76 detects the switchback by the light reflection type switchback sensor 76 with respect to the single-side printed envelope F which is guided to the switchback conveying path SR by the plurality of roller pairs R4 and conveyed by the plurality of roller pairs R4. Yes.

  Thereafter, the single-side printed envelope F guided to the switchback conveyance path SR is inclined to the upper portion of the left side surface of the housing 2 and the sheet guide plate 83 provided to be inclined to the back surface of the second discharge tray 82. The rear end portion Fe that is conveyed between the sheet guide side plate 2b2 and the leading end in the conveyance direction of the envelope F is the envelope protrusion in the second registration mechanism portion 90 provided in the switchback conveyance path SR. Since the registration operation is performed by being abutted against the abutting member 91, the skew of the envelope F is corrected before the other side (Fb side) of the envelope F is printed. Will be described in detail.

  Then, after the skew feeding to the envelope F that has been reversed by the second registration mechanism 90 is corrected, when the envelope F is switched back, the leading position of the envelope F that has been printed on one side is reversed, and the envelope F The flap portion Fd formed at the front end portion Fc becomes the head in the transport direction when printing the other surface (Fb surface). Thereafter, the transport direction is switched by the third flipper 77 and the light reflection type re-feed sensor 78. When the printing is performed on the other surface (Fb surface) of the envelope F, the registration operation by the registration roller pair 42 is performed again while facing the registration sensor 41 and the registration roller pair 42 installed in the circulation conveyance path JR. Without performing this, when the flap portion Fd of the envelope F is detected by the re-feed sensor, the registration roller pair 42 is rotated to convey the envelope F toward the printing portion 60, and the other side of the envelope F (Fb ) By printing by the printing unit 60, which enables double-sided printing of the envelope F.

  Furthermore, the section in which the envelope F is transported by the plurality of roller pairs R1 in the circulation transport path JR is a constant speed section in which the envelope F is transported at a constant transport speed, but the second in the circulation transport path JR. In the downstream of the pair of rollers R2 before the branch sensor 73, in a variable speed section that includes a discharge conveyance path HR and a switchback conveyance path SR, a variable speed section that is variable to a speed higher than a certain conveyance speed according to the length of the envelope F. By providing this variable speed section, when the envelope F is printed in the order of front side printing, back side printing, front side printing, back side printing,..., The intervals between adjacent envelopes F are substantially equal. In addition, printing can be performed with good timing.

  Further, the control unit 100 described above includes a CPU 100a that controls each unit, a ROM 100b that stores information such as an operation program of the double-sided printing device 1 that is fixed in advance, and the double-sided printing device 1 as illustrated in FIG. RAM 100c that temporarily stores information that can be changed during the operation, and the envelope F fed by the paper feed unit 20 with respect to the inkjet head 61 when it passes through the first and second top edge sensors 44 and 45. In order to control the ejection start of the ink IK, first and second counters 100d and 100e for counting encoder pulses from the motor with encoder 54 provided in the belt platen unit 50 are provided.

  Further, the control unit 100 receives print data D created by a personal computer PC or the like via the interface 101, and supplies the operation panel unit 10, the paper feed table 21, the paper feed roller 23, and the feeding roller 24. A paper unit 20, a registration roller pair 42, a belt platen unit 50, a printing unit 60 to which an ink jet printing method is applied, a plurality of roller pairs R0 to R4 and first to third flippers 72, 74, 77, various optical sensors 41, 44, 45, 71, 73, 76, 78 provided in the conveyance path, and the second registration mechanism 90 provided in the switchback conveyance path SR are controlled. is doing.

  Here, the second registration mechanism 90 that performs the registration operation after inverting the envelope F will be described in detail with reference to FIGS.

  The second registration mechanism 90 described above is the main part of this embodiment, and when printing the other surface (Fb surface) of the envelope F, the leading end in the transport direction of the envelope F that is switched back. Is on the side of the flap Fd having a weak waist, and if the registration operation is performed by the registration roller pair 42 provided in the circulation conveyance path JR on the flap Fd side, it becomes unstable. Therefore, before the envelope F is switched back, The other end surface (Fb) of the envelope F is abutted against the envelope abutting member 91 installed in the switchback conveying path SR by abutting the rear end portion Fe of the envelope F on which the surface (Fa surface) is printed and reversed. The skew correction of the envelope F is performed before printing the surface.

  Specifically, referring to FIGS. 5A and 5B, in the second resist mechanism portion 90, the envelope abutting member 91 is bent and formed in an inverted U shape using a sheet metal material, and the envelope. A flat surface 91a against which the rear end portion Fe of F is abutted is formed to be wide and flat corresponding to the width direction of the envelope F.

  In addition, a pair of upper and lower leaf springs 92 and 93 serving as gripping means for temporarily gripping the envelope F are spaced apart from each other on the flat surface 91a of the envelope abutting member 91 with the switchback transport path SR interposed therebetween. The two are opposed to each other, are bent into a reverse H-shape and a H-shape, and are integrally attached to the flat surface 91a.

  At this time, when only the upper leaf spring 92 of the pair of upper and lower leaf springs 92 and 93 is shown in an enlarged scale in FIG. 5B, the leaf spring 92 is held on the left and right in the width direction of the envelope F by the gripping pieces 92a and 92b. Is bent in an inverted letter shape, and the lower leaf spring 93 is vertically symmetrical with respect to the upper leaf spring 92. Therefore, the width direction of the envelope F is determined by the pair of upper and lower leaf springs 92, 93. Can be gripped temporarily.

  In addition, a wide endless belt 97 is stretched between a driving pulley 95 and a driven pulley 96 that are rotationally driven by an encoder motor 94 on the back side of the second paper discharge tray 82 so that the endless belt 97 can rotate. Since the upper bent piece 91b bent and formed on the envelope abutting member 91 is connected to the endless belt 97, the envelope abutting member 91 is switched to the switchback conveying path according to the length of the envelope F. It is possible to reciprocate in the direction of the arrow along SR. Thereby, it is possible to cope with envelopes F having all kinds of lengths at the time of skew correction before printing the other side (Fb side) of envelope F after the front and back sides are reversed.

  When printing a sheet (not shown), the envelope butting member 91 is retracted to an initial position that does not interfere with the sheet in the switchback conveyance path SR.

  Further, among the plurality of roller pairs R4 provided in the switchback conveying path SR, the roller pair R4 facing the envelope abutting member 91 at a distance from each other, the driven roller driven by the drive roller is a pressing mechanism and nip releasing mechanism 98. It is provided so as to be able to contact with and separate from the envelope F via.

  As described later, the pressing mechanism / nip releasing mechanism (hereinafter referred to as a pressing mechanism) 98, as described later, abuts the rear end portion Fe of the envelope F against the envelope abutting member 91 and then moves the envelope F to a pair of upper and lower plates. A function of temporarily releasing the nip to the envelope F with respect to the roller pair R4 that is installed opposite to the envelope abutting member 91 in the switchback conveying path SR while being held by the springs 92 and 93. ing.

  Next, the operation of the second registration mechanism 90 configured as described above will be described with reference to FIGS.

  First, as shown in FIG. 6A, the envelope abutting member 91 provided in the second registration mechanism portion 90 is an initial stage that does not interfere with the conveyance of the envelope F or the paper in the switchback conveyance path SR at the initial stage. Although it is retracted to the position, when an envelope printing key (not shown) provided on the operation panel unit 10 is pressed, it is bridged between the driving pulley 95 and the driven pulley 96 via the motor 94 with an encoder. The endless belt 97 is rotated, and the envelope abutting member 91 connected to the endless belt 97 is moved to a predetermined position according to the length of the envelope F along the switchback conveying path SR. That is, with respect to the length L of the envelope, between the flat surface 91a of the envelope abutting member 91 and the nip point of the roller pair R4 facing the envelope abutting member 91 in the switchback conveying path SR with a distance therebetween. Is moved to a predetermined position where the distance K is slightly shorter than the envelope length L (K <L), and the envelope abutting member 91 is moved and stopped.

  At this time, the length L of the envelope F is obtained by using a method of utilizing length information from a sheet length detection unit (not shown) provided on the sheet feed table 21 and one side (Fa surface) of the envelope F. Any method of obtaining the period from the rear end portion Fe of the envelope F to the front end portion Fc passing the first top edge sensor 44 from the product of the time measured by a timer (not shown) and the conveyance speed before printing may be used. Then, the length L of the envelope F and the distance K described above may be stored in advance in the RAM 100c of the control unit 100 and taken out from the RAM 100c as necessary.

  Thereafter, the envelope F, which is printed on one side (Fa side) and then turned upside down, has the other side (Fb) up and the rear end Fe of the envelope F is the leading end in the transport direction. The roller pair R4 that is disposed opposite to the abutting member 91 is conveyed toward the envelope abutting member 91. At this time, the driven roller of the roller pair R4 is moved by the pressing mechanism 98. It is pressed against the driving roller via the envelope F.

  Next, as shown in FIG. 6 (b), the roller pair R 4 described above is further rotated to enter between a pair of upper and lower leaf springs 92, 93 attached to the flat surface 91 a of the envelope abutting member 91. Then, when the rear end portion Fe of the envelope F is abutted against the flat surface 91a of the envelope abutting member 91, the rear end portion Fe of the envelope F is bent, and the envelope F is a pair of upper and lower plates. The springs 92 and 93 are temporarily held by a weak biasing force.

  Next, as shown in FIG. 6C, while the envelope F is gripped by a pair of upper and lower leaf springs 92 and 93, the driven roller is temporarily moved out of the roller pair R4 from the pressing mechanism (nip release mechanism) 98. When the nip to the envelope F by the roller pair R4 is temporarily released, the conveyance of the envelope F is stopped and the envelope is resisted against the weak biasing force of the pair of upper and lower leaf springs 92, 93. Since the deflection T {FIG. 6 (b)} generated in the rear end portion Fe of F disappears and the rear end portion Fe of the envelope F is aligned along the flat surface 91a of the envelope abutting member 91, the other surface of the envelope F The skew of the envelope F can be reliably corrected by the envelope abutting member 91 before printing (Fb surface).

Next, as shown in FIG. 6D, after the registration operation after inverting the envelope F is completed,
By rotating the roller pair R4 in the reverse direction to the above and pressing the driven roller again from the pressing mechanism 98 to the driving roller through the envelope F from the roller pair R4, the envelope F is switched back and the envelope Although it faces the registration roller pair 42 provided in the circulation conveyance path JR with the flap portion Fd side of F leading, as described above, the registration roller pair 42 needs to perform registration operation on the flap portion Fd having a low waist. Therefore, the envelope F can be reliably conveyed to the printing unit 60, and can be printed on the other surface (Fb surface) of the envelope F by the printing unit 60.

  As described above, according to the double-sided printing apparatus 1 according to the present invention, after setting the rear end portion Fe opposite to the flap portion Fd formed on the front end portion Fc of the envelope F to the front in the sheet feeding direction, the envelope F is fed by the paper feeding unit 20 and the rear end portion Fe of the envelope F is abutted against the first registration mechanism portion (registration roller pair) 42 before printing one surface (Fa surface) of the envelope F. After correcting the skew of the envelope F, after printing one surface (Fa surface) of the envelope F with the printing unit 60, the front and back of the envelope F are reversed in the reverse conveyance path (circulation conveyance path) JR. The envelope abutting member 91 in the second resist mechanism portion 90 in which the rear end portion Fe of the envelope F that has been inverted before printing the other surface (Fb surface) of the envelope F is provided in the switchback transport path SR. To correct the skew of the envelope F, and after that, the envelope F is switched back to When the envelope F is transported again toward the printing unit 60 through the first registration mechanism unit (registration roller pair) 42 with the top portion Fd side as the head, the control unit 100 includes the second registration mechanism unit 90. Since the first registration mechanism portion (registration roller pair) 42 is controlled so that the skew correction is not performed on the flap portion Fe of the envelope F that has been switched back after the skew correction in step S1, the switchback transport path SR The envelope abutting member 91 in the second resist mechanism 90 provided therein can reliably correct the skew of the envelope F before printing the other surface (Fb surface) and switch back to the first one. Even if the flap portion Fd of the envelope F that faces the printing portion 60 again through the registration mechanism portion (registration roller pair) 42 of the first registration mechanism portion 42 is weak, registration movement by the first registration mechanism portion (registration roller pair) 42 is performed. Since there is no need to perform, it can be reliably conveyed to the printing unit 60 envelopes F without damaging the flap portion Fd of the envelope F.

1 ... Double-sided printing device,
2 ... Case, 2b1 ... Paper stand guide side plate,
DESCRIPTION OF SYMBOLS 10 ... Operation panel part 20 ... Paper feed part, 21 ... Paper feed stand, 23 ... Paper feed roller, 24 ... Rolling roller, 25 ... Friction plate,
26: Encoder motor, 41: Registration sensor,
42: First registration mechanism (registration roller pair),
43 ... Encoder motor, 44 ... First top edge sensor,
45. Second top edge sensor,
50 ... Belt platen section, 51 ... Endless belt platen,
60 ... printing section, 61 ... inkjet head,
71: First branch sensor, 73: Second branch sensor, 75: Paper discharge sensor,
76: Switchback sensor, 78: Re-feed sensor,
80: paper discharge unit, 81: first paper discharge tray, 82: second paper discharge tray,
90 ... Second resist mechanism, 91 ... Envelope abutting member,
92, 93 ... gripping means (a pair of upper and lower leaf springs),
94: Encoder motor, 95 ... Drive pulley, 96 ... Driven pulley,
97: Endless belt, 98: Press mechanism / nip release mechanism (press mechanism),
100 ... Control unit, 100a ... CPU, 100b ... ROM, 100c ... RAM,
100d ... 1st counter, 100 ... 2nd counter, 110 ... Power supply part,
KR: paper feed conveyance path, JR: reverse conveyance path (circulation conveyance path), BR: branch path,
HR: paper discharge conveyance path, SR: switchback conveyance path,
D ... print data, F ... envelope, Fa ... cover, Fb ... back paper, Fc ... tip,
Fd ... flap part, Fe ... rear end part, Ff ... glue margin, IK ... ink,
R0 to R4: Roller pair, T: Deflection of the tip of the envelope F.

Claims (3)

In a double-sided printing device that prints images and text on both sides of an envelope,
Paper feeding that feeds the envelopes stacked one by one on the paper feed tray by setting the rear end on the opposite side of the flap formed at the leading edge of the envelope as the head in the paper feeding direction. And
A printing unit for selectively printing one side and the other side of the envelope;
It is installed upstream of the printing unit in the transport direction, and temporarily abuts the rear end of the envelope fed by the paper feeding unit before printing one surface of the envelope. A first registration mechanism that corrects the skew of the envelope and that conveys the envelope to the printing unit when printing one side of the envelope that has been skew-corrected and when printing the other side of the envelope And
A reversing conveyance path for reversing and conveying the other surface to the printing unit with respect to the envelope on which the one surface is printed by the printing unit;
The envelope which is connected to the reversing conveyance path and is reversed is switched back so that the flap side of the envelope is at the head, and the envelope is conveyed again toward the printing unit via the first registration mechanism unit. A switchback transport path to
An envelope abutting member is installed in the switchback conveying path, and a second registration mechanism that corrects skew of the envelope by abutting a rear end portion of the envelope against the envelope abutting member;
A paper discharge unit for discharging the printed envelope;
A control unit for controlling each unit,
The control unit controls the first registration mechanism unit so that the skew correction is not performed on the flap portion of the envelope that is switched back after the skew correction is performed by the second registration mechanism unit. Double-sided printing device. The second registration mechanism part is:
Gripping means for temporarily gripping the envelope when the rear end of the envelope is abutted against the envelope abutting member;
It is installed in the switchback conveyance path so as to face the envelope abutting member at a distance, and the rear end of the envelope reversed in the reversal conveyance path is rotated in a direction to abut against the envelope abutting member. And a pair of rollers that reversely reverse the envelope after correcting the skew by the envelope abutting member and switch the envelope back toward the printing side via the first registration mechanism portion, and
A nip releasing mechanism for temporarily releasing a nip to the envelope with respect to the roller pair after abutting a rear end portion of the envelope against the envelope abutting member;
The double-sided printing apparatus according to claim 1, further comprising: The second registration mechanism part is:
The double-sided printing apparatus according to claim 1, further comprising a moving unit that moves the envelope abutting member to a predetermined position according to a length of the envelope along the switchback conveyance path. .

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