JP4864533B2 - Printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer having a printing gap automatically set mechanism automatically and constantly setting the gaps between a printing medium and a printing head according to the thickness of the printing media in a simple construction as much as possible. <P>SOLUTION: The printing gap automatically set mechanism is constituted of an upper side conveying guide arranged in both front and back side of the printing medium conveying direction of a printing head movement path and in which boss portions are arranged in the lower face of the end portion of a printing head movement path, a pushing up roller supported while being biased upward to both the boss portions and the opposite sides of the printing media conveying face by biasing members, and a push up roller elevating means elevating the push up rollers to the boss portions via the biasing means when printing and lowering the same to the position where the push rollers do not project above the printing medium conveying face when not printing, and the distance between the planar face connecting the lower end faces of the boss portion and the lower end faces of the printing head moving through the printing head movement path is set equal to the predetermined printing gap of the printing head. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a printing apparatus, and more particularly to a printer having a function of automatically setting a constant distance between a printing medium and a printing head according to the thickness of the printing medium.

  In the dot impact printer, the print head is moved along the print surface of the medium that has been transported to the print position by the transport roller and stopped, the wire is projected from the head nose of the print head, and the print medium is applied from above the ink ribbon. Tap to print. In an inkjet printer, the print head is moved along the print surface of a medium that has been transported to a print position by a transport roller and stopped, and ink is ejected from the head nose of the print head onto the print medium for printing. In any case, in order to ensure a constant print quality, it is necessary to provide a mechanism for keeping the distance between the print medium and the print head (print gap) constant regardless of changes in the thickness of the print medium. .

  In a dot impact printer, in order to keep the distance between the print medium and the print head constant, a ribbon mask is provided at the lower end of the print head, and the distance from the head nose to the lower surface of the ribbon mask is set equal to the standard print gap. This is realized by pushing up the printing medium conveyed to the printing position from below with a platen until the printing surface of the printing medium comes into contact with the lower surface of the ribbon mask.

  However, in the ink jet printer, if a mask corresponding to a ribbon mask is used, the mask cannot be used because the mask comes into contact with the print medium immediately after printing and causes ink rubbing or bleeding. In addition, when printing without a mask, ink flows out only by the print medium coming into contact with the nozzle, so a mechanism that can secure a predetermined print gap without using a mask is desired.

Conventionally, various mechanisms for automatically keeping the distance between the print medium and the print head constant according to the thickness of the print medium have been disclosed in patent documents.
In Patent Document 1, a transport roller is disposed on the upper side of the transport surface on both front and rear sides in the print medium transport direction of the print head moving passage, and a line connecting the lower end surfaces of the transport rollers on both sides and the lower end surface virtual movement of the print head. The gap with the surface is made equal to the printing gap, and a pressing roller is provided below the one conveying roller so as to be movable up and down. A platen is coupled to the support shaft of the pressing roller, and the platen is biased upward by a spring. Accordingly, there is disclosed a technique in which the distance between the print medium and the print head is kept constant even when the thickness of the print medium changes.

  In Patent Document 2, a platen roller is provided so as to be able to move up and down below the print head moving path, and a support shaft of the platen roller and a support shaft of a pressing roller provided so as to be able to move up and down below the conveying roller are connected to each other. And the connecting member is always urged upward by the urging member.

  In Patent Document 3, upper transport guides are provided on both front and rear sides of the print head moving path in the print medium transport direction, the distance between the lower end surface of the transport guide and the lower end surface of the print head is equal to the print gap, and upper transport is performed. There is a description in which a lower conveyance guide corresponding to a platen is provided on the lower side of the guide so as to be movable up and down, and the lower conveyance guide is always urged upward by an urging member.

Further, Patent Document 4 includes a print medium thickness detecting unit and a platen moving unit including a cam and a motor, and driving and controlling the platen moving unit in accordance with the detected thickness, so that the print medium and the print head can be controlled. It describes what keeps the interval constant.
Japanese Patent Laid-Open No. 6-47966 JP-A-8-156352 JP 2000-141791 A JP 2001-277618 A

  However, in the above three prior arts, the urging member constantly urges the platen upward, so that the conveyance resistance is large when the print medium is conveyed to the print position, and the speed or conveyance is high. There is a problem of affecting accuracy. Further, in Patent Document 4, it is necessary to provide a thickness detecting means and a platen moving means, which causes an increase in the cost of the apparatus, and the failure of the signal system and the control system of the thickness detecting means and the platen moving means. There is a problem of increasing the causes of printing defects.

  The present invention has been made in view of the above-described problems, and the problem thereof is as simple as possible, that is, it does not require a thickness detecting means, a platen, and a platen moving means, and is a printing medium. It is an object of the present invention to provide a printing apparatus provided with a print gap automatic setting mechanism that automatically sets the interval between the print medium and the print head to be constant according to the thickness of the print medium.

In order to solve the above problems, the present invention provides a transport roller for transporting a print medium to a print position, a transport guide for guiding a print medium transported by the transport roller along a predetermined transport surface, and the print A print head that faces the print medium stopped at a position and is moved in a direction perpendicular to the transport direction of the print medium to perform printing on the print medium, and an interval between the print medium and the print head In a printing apparatus having a print gap automatic setting mechanism that automatically sets the print gap to a constant value, the print gap automatic setting mechanism is disposed on both sides of the print head moving path in the front and rear directions in the print medium conveying direction. an upper conveyance guide protrusions substantially semicircular cross-sectional shape on the lower surface is convex downward end is provided, with upward by an urging member on the opposite side of the double convex portion of the printing medium transporting surface And a push-up roller which is supported, while the print head performs a printing operation raises toward the push-up roller to the protrusion via a biasing member, and the conveying roller conveys the printing medium And a push roller raising / lowering means for lowering the push roller to a position that does not protrude upward from the print medium conveying surface, and a plane connecting the lower ends of the convex portions on both sides and a print head moving path The distance from the lower end surface is set equal to a predetermined print gap of the print head (claim 1).

  It is desirable that the lifting roller raising / lowering means is composed of an electromagnetic solenoid.

  According to the invention of claim 1, the print gap automatic setting mechanism is provided with convex portions having a predetermined protrusion amount on the lower surface of the end portion of the upper transport guide on the print head moving path side, and below these convex portions, It is composed of push-up rollers supported by the urging member and push-up roller raising / lowering means for raising and lowering these push-up rollers toward the convex part, and is not provided with thickness detecting means, platen or platen raising / lowering means. Therefore, the configuration is simple, the installation is easy, and the manufacturing cost is low. During printing, the push-up roller is lowered to a position where it does not protrude upward from the printing medium conveyance surface, so that resistance to printing medium conveyance is not given, and printing defects are not caused by rubbing ink immediately after printing. . Further, since the distance between the convex portion and the lower end surface of the print head is set equal to the predetermined print gap, the predetermined distance between the print head and the print medium is automatically set only when the print medium exists at the print position. An interval is set and maintained.

  According to the invention of claim 2, since the push-up roller can be moved between a position where it does not protrude into the conveyance path and a position where it presses against the convex portion with a short stroke of the plunger of the electromagnetic solenoid, the print gap is automatically set. The mechanism can be downsized. In addition, the raising / lowering speed of the push-up roller can be increased as compared with the case where the push-up roller raising / lowering means is composed of a motor and a screw mechanism, leading to an improvement in printing speed.

Next, embodiments of the present invention will be described with reference to the drawings.
1 is a perspective view showing a peripheral part of a print gap automatic setting mechanism of a printing apparatus according to the present invention, FIG. 2 is a perspective view showing the part disassembled vertically, and FIG. 3 is an open view of FIGS. FIG. 4 is a perspective view of the upper conveyance guide before and after the print head moving path when viewed from the lower side when the guide is in the open position, FIG. 4 is a perspective view of the state in which the open guide of FIG. 2 is closed, and FIG. FIG. 6 is a perspective view of the upper conveyance guide before and after the print head moving path when the open guide is in the closed position, as viewed from below. FIG. 6 is a schematic side view showing only the print gap automatic setting mechanism of the present invention. FIGS. 7 to 9 are explanatory views of the operation of the printing apparatus, and FIG. 10 is a side view showing another example of the push-up roller lifting means.

  The illustrated printing device is for a financial institution for printing transaction contents on a binding-type passbook as a printing medium. After transporting and moving the print head at the standby position in a direction perpendicular to the direction of carrying the passbook, printing on a predetermined line of the passbook, then carrying the passbook in the reverse direction from the print position to the passbook entry / exit port It is configured to discharge.

  In FIG. 1, reference numeral 1 denotes an ink cartridge loaded in a predetermined loading position of the ink jet printer, and is supplied from each ink cartridge to a print head (not shown) through a tube (not shown). As is well known, the print head is mounted on a carriage slidably held by a guide rod, and a belt wound between pulleys provided on both sides and a pulley coupled to a motor is coupled to the carriage. Therefore, the print head moving passage 2 is moved along the guide rod by rotation control of the motor.

  The print head moving passage 2 extends in a direction perpendicular to the passbook transport direction in the passbook transport path formed between the upper transport guide 3 and the lower transport guide 4 arranged at a predetermined interval in the vertical direction. As shown in FIG. 3, of the upper conveyance guide 3, an upper front conveyance guide 3a provided on the bankbook take-in / discharge port side, and the passbook take-in / discharge from the upper front conveyance guide 3a. It is formed between the upper rear transport guide 3b provided at a position approximately equal to the width of the head nose of the print head in the opposite direction to the outlet.

  Then, the print head moving path 2 is shielded in the vicinity of the print head moving path 2 on either one of the upper front transport guide 3a and the upper rear transport guide 3b (upper front transport guide 3a in the illustrated example). An open guide 5 for opening is fixed to a shaft 6 rotatably supported on the upper surface of the front conveyance guide 3a, and a motor 7 attached to one end of the shaft 6 and the upper surface of the front conveyance guide. The drive gear 8a, the idle gear 8b, and the driven gear 8c fixed to each other transmit the rotational force at the time of forward or reverse rotation of the motor to the shaft 6, and the open guide 5 is shown in FIGS. As shown in FIGS. 4 and 5, the print head moving passage 2 is raised to an open position where the print head moving passage 2 is opened upward, or is flattened to a shielding position where the upper surface of the print head moving passage 2 is shielded. Ruyo It has become.

The ends of the upper front conveyance guide 3a and the upper rear conveyance guide 3b on the side of the print head moving passage 2 are formed with a plurality of protrusions 31 and 32 at equal intervals, each formed in a single-tooth comb shape. The protrusions are formed so as to face each other.
As shown in FIGS. 1 and 2, the open guide 5 is formed in a gate shape, the base portions of the leg portions on both sides are fixed to the shaft 6, and the guide portion 50 corresponding to the gate top portion when the open guide stands is A plurality of protrusions 51 and 52 are arranged at equal intervals on the front side, and are formed in a double-tooth shape. The protrusions 51 and 52 are formed on the protrusions 31 and 32 of the upper front conveyance guide 3a and the upper rear conveyance guide 3b when the open guide 5 is flattened as shown in FIG. 4 and shields the print head moving path. It is configured to fit in the gap between them and close the gap.

The upper front conveyance guide 3a is provided with a freely rotating press roller PR1 constituting a conveyance roller on the shaft 10 supported at a fixed position on the upper surface thereof with a predetermined interval in the axial direction. The lower end portion of the pressing roller PR1 protrudes downward from a hole 33 formed in the upper front conveyance guide 3a.
The upper rear conveyance guide 3b is also provided with a pressing roller PR2 similar to the pressing roller PR1 with a predetermined interval in the axial direction on a shaft 11 supported at a fixed position on the upper surface thereof. The lower end of the roller PR2 protrudes downward from a notch 34 formed in the upper rear conveyance guide 3b.

  As shown in FIG. 2, the lower conveyance guide 4 has a length that is substantially equal to the length of the upper front conveyance guide 3a and the upper rear conveyance guide 3b. The lower conveyance guide 4 is formed with a hole 41 and a notch 42 at positions facing the holes 33 of the upper conveyance guide 3a and the notches 34 of the upper conveyance guide 3b. The shafts 13 and 14 are held in positions corresponding to the shafts 10 and 11 of the upper transport guides 3a and 3b by a bearing or other support means (not shown) so as to be rotatable and movable up and down. Drive rollers DR1 and DR2 are fixed, and the upper portions of the drive rollers DR1 and DR2 are fitted into the holes 41 and the notches 42, respectively, and the upper portions of the rollers protrude upward from the upper surface of the lower conveyance guide 4. Has been. The shafts 13 and 14 are constantly urged upward by an urging means (not shown) and are given a rotational force from a conveyance motor (not shown) by a transmission belt (not shown). Thus, the lower drive rollers DR1 and DR2 are always pressed against the upper press rollers PR1 and PR2, and the bankbook can be sandwiched and conveyed between them.

  In the above-described configuration, the open guide 5 is controlled so that the open guide motor 7 is rotationally driven in a certain direction while the print head performs a printing operation, that is, when the print head moves in the print head moving passage 2. The open guide 5 is erected to open the print head moving passage 2, but it is open when the passbook is transported from the passbook take-in / discharge port to the print position and during the transfer from the print position to the passbook take-out / discharge port. When the motor 7 is rotationally driven in the opposite direction, the open guide 5 is flattened and the print head moving path 2 is shielded.

  Next, the configuration of the print gap automatic setting mechanism in the present invention will be described. On the lower surfaces of the protrusions 31 and 32 on the print head moving path 2 side of the upper front conveyance guide 3a and the upper rear conveyance guide 3b, as shown in FIG. 6, the cross-sectional shape is convex downward. Almost semicircular convex portions P1 and P2 are provided. And the position D of the lower end surface of these convex parts P1 and P2 is the distance D from the surface f1 connecting the lower end surfaces to the lower end surface f2 of the head nose HN of the print head PH that moves in the print head moving path. It is set to be equal to the standard value of the print gap of the print head.

  As shown in FIG. 2, the lower transport guide 4 has a plurality of positions (positions corresponding to the protrusions P1 and P2 and at appropriate intervals in the extending direction of the protrusions) (see FIG. 2). 2 has a total of 4 holes 43 and 44, and push-up rollers LR1 and LR2 are fitted in the holes so as to be movable up and down. Each push-up roller LR1, LR2 is rotatably supported via a shaft 17 by a U-shaped metal fitting 16 fixed to the tip of a plate spring 15 as an urging member, and a lower end of each plate spring 15 is a common holding member 18 is fixed. The holding member 18 is supported by a guide member (not shown) so as to be movable up and down, and is connected via a link 21 to a plunger 20 of an electromagnetic solenoid 19 which is fixed to the main body of the printing apparatus.

  When the electromagnetic solenoid 19 is in a non-energized state, the holding member 18 is maintained at a low position via the plunger 20 and the link 21 that have been returned to the home position. Therefore, the push-up rollers LR1, LR2 Is maintained at a position equal to or lower than the upper surface of the lower conveyance guide 4 forming the conveyance surface, but when the electromagnetic solenoid 19 is energized, as shown in FIG. The holding member 18 is moved to a higher position via the plunger 20 and the link 21. Therefore, the upper end surfaces of the push-up rollers LR1 and LR2 press the convex portions P1 and P2 of the upper transport guides 3a and 3b, respectively. It is configured to be raised to a position.

  The electromagnetic solenoid 19 is energized only while the print head PH performs a printing operation, and is de-energized when the bankbook is fed and when the bankbook is conveyed.

As described above, the print gap automatic setting mechanism according to the present invention is formed on the upper transport guides 3a and 3b on both sides of the print head moving passage 2 and is on a plane having a distance equal to the print gap between the print head moving surfaces. Convex portions P1 and P2 having lower end portions thereof, push-up rollers LR1 and LR2 which are provided on the lower side of the conveying surface so as to face the respective convex portions and are always urged in the direction of the convex portion by the urging member, From the electromagnetic solenoid 19 that maintains the push-up roller in a position that does not protrude upward from the conveyance surface via the biasing member when energized, and moves the push-up roller to a position that presses the convex portion via the biasing member when energized. It is configured.
In the present invention, since the conventional platen, platen lifting / lowering means, and thickness detecting means are not provided, as is clear from FIG. 6, the automatic print gap securing mechanism has a very simple structure. It is worth mentioning that it is small and small.

Next, the operation of the print gap automatic setting mechanism during operation of the printing apparatus based on the above configuration will be described.
As shown in FIG. 7, during normal conveyance for transferring from the passbook intake / discharge port to the print position, from the print position to the passbook intake / discharge port, or for line feed during the printing operation, The open guide 5 is flattened and held at a position where the print head moving passage 2 is shielded, and the electromagnetic solenoid 19 is held in a non-energized state, so that the upper end surfaces of the push-up rollers LR1 and LR2 are transport surfaces. Are maintained on the same plane. Therefore, the bankbook N can be conveyed in an arbitrary direction by a plurality of pairs of upper and lower conveying rollers PR1, DR1; PR2, DR2. Since the convex portions P1 and P2 are formed in a semicircular cross section, no resistance is given to the bankbook N being conveyed.

  Then, when the passbook in the spread state is conveyed to a predetermined printing position, that is, the line on which transaction contents are to be printed is conveyed to a position facing the nozzle of the print head PH, and is stopped, it is not shown in FIG. However, the open guide 5 is raised, the print head moving passage 2 is opened, and the electromagnetic solenoid 19 is energized. As shown in FIG. 9, the plunger 20, the link 21, the holding member 18 and the leaf spring 15 are moved. Thus, the push-up rollers LR1 and LR2 are raised and the lower surface of the passbook N is pushed up toward the convex portions P1 and P2, so that the upper surface of the pushed up passbook is received by the front and rear convex portions P1 and P2. Therefore, a predetermined printing gap -D is automatically set and secured between the printing surface of the bankbook N and the head nose HN of the printing head PH moved through the printing head moving passage 2.

In the embodiment shown in FIG. 6, the plate spring 15 is used as a biasing member that biases the push-up rollers LR1 and LR2 in the direction of the convex portions P1 and P2, and the electromagnetic solenoid 19 is used as the push-up roller lifting means. In the case of a leaf spring, it is possible to move between a position where the push-up roller does not protrude into the conveyance path and a position where the push-up roller is pressed against the convex portions P1 and P2 with a short stroke of the plunger of the electromagnetic solenoid. That is, there is an advantage that a small electromagnetic solenoid can be used. Further, the plunger of the electromagnetic solenoid has an advantage that the raising / lowering speed of the raising roller can be increased as compared with the case where the raising roller raising / lowering means is constituted by a motor and a screw mechanism.
However, the urging member is not limited to the leaf spring, and as illustrated in FIG. 10, a coil spring 15 ′ having an appropriate spring coefficient is moved up and down between the support fitting 16 of the push-up rollers LR 1 and LR 2 and the holding member 18. It can also be used by being wound around a support shaft 22 provided freely.

FIG. 3 is a perspective view showing a peripheral portion of a print gap automatic setting mechanism of the printing apparatus according to the present invention. The perspective view which decomposes | disassembles and shows the same part up and down. FIG. 3 is a perspective view of the upper conveyance guide before and after the print head moving path when the open guide of FIGS. 1 and 2 is in the open position, as viewed from below. The perspective view of the state which closed the open guide of FIG. FIG. 5 is a perspective view of the upper conveyance guide before and after the print head moving path when the open guide of FIG. FIG. 3 is a schematic side view showing only a portion of a print gap automatic setting mechanism according to the present invention. Explanatory drawing of the effect | action at the time of bankbook conveyance of a printing apparatus. Explanatory drawing of an action at the time of open guide open of a printer. Explanatory drawing of the action | operation at the time of the printing operation of a printing apparatus. The side view which shows the other example of a raising roller raising / lowering means.

Explanation of symbols

PH print head HN head nose 2 print head moving path 3 upper conveyance guide 3a upper front conveyance guide 3b upper rear conveyance guide P1, P2 convex portion 4 lower conveyance guide 5 open guide PR1, DR; PR2, DR2 conveyance roller LR1, LR2 Push-up roller 15 Leaf spring (biasing member)
18 Holding member 19 Electromagnetic solenoid N Printing medium (passbook)

Claims (2)

A transport roller for transporting the print medium to a print position; a transport guide for guiding the print medium transported by the transport roller along a predetermined transport surface; and the print medium stopped at the print position; A print head that is moved in a direction perpendicular to the conveyance direction of the print medium and performs printing on the print medium, and includes a print gap automatic setting mechanism that maintains a constant distance between the print medium and the print head. In the printing device
The print gap automatic setting mechanism is disposed on both front and rear sides in the print medium transport direction of the print head moving passage that moves when the print head performs a printing operation, and has a cross-sectional shape on the lower surface of the end portion on the print head moving passage side. An upper conveyance guide provided with a substantially semicircular convex portion which is a convex surface below, and a push-up roller supported by being biased upward by a biasing member on the opposite side of the both convex portions of the conveyance surface; While the print head performs a printing operation, the push-up roller is raised toward the convex portion via the biasing member, and the push-up roller conveys the print medium while the carry roller conveys the print medium. And a push roller raising / lowering means for lowering to a position that does not protrude above the surface, and the distance between the plane connecting the lower end portions of the convex portions on both sides and the lower end surface of the print head moving in the print head moving path is Printing apparatus characterized by being set equal to the predetermined printing gap of the print head.   The printing apparatus according to claim 1, wherein the push-up roller raising / lowering means comprises an electromagnetic solenoid.

Images