JPH08197754A - Shuttle printer - Google Patents

Abstract

PURPOSE: To enable high speed printing by driving the printing head of a shuttle printer so as to allow the same to advance and retreat while shaking the printing pins of the head to reduce friction resistance at the time of printing. CONSTITUTION: A printing head wherein a plurality of printing pins 13 are arranged in one row in the direction crossing the transfer direction of a medium to be recorded at a right angle is fixed while a main guide piece 31 fitted with guide holes 31a guiding and supporting all of the printing pins 13 is reciprocally shaken in the row direction. In this case, the diameter Do and length E of the guide holes 31a of the main guide piece 31 are set so that one side surfaces of the leading end parts of the printing pins 13 are laterally pressed by the edges of the regions near to the base parts of the printing pins 13 in the guide holes at the time of reciprocal shaking and the other side surface of the leading end parts thereof are bent in the row direction of the printing pins 13 in a non-contact state or without being pressed laterally with respect to the edges of the diagonal positions in the guide holes 31a from the relation with the diameter do and shaking quantity of the printing pins 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention arranges a plurality of unit printing mechanisms for advancing and retracting printing pins in a line, and these printing pins are arranged in a line in a direction intersecting a feeding direction of a printing medium. In addition, the present invention relates to the structure of a shuttle printer in which these print pins are simultaneously swung in a direction intersecting the feeding direction of a recording medium while printing is performed.

[0002]

2. Description of the Related Art In a shuttle printer of this type, as described in Japanese Patent Publication No. 57-52913, printing pins are arranged in a row in the left-right direction intersecting the feeding direction of a print-receiving medium such as paper. The unit printing mechanism is fixedly arranged in a row in the above, and the tip side of the printing pin protruding from each printing mechanism is reciprocally rocked in the lateral direction of the recording medium via the tip guide member and the movable body. It is disclosed.

[0003]

However, in the above-mentioned prior art, since the number of characters printed by one printing pin is as large as about 4 digits, the amount of bending of the tip of each printing pin is naturally large. As a result, the tip guide member that slidably guides the tip side of each print pin without twisting is attached to the swingable movable body so as to rotate independently, so that the number of parts increases, There was a problem that the structure became complicated.

An object of the present invention is to solve the above problems in the prior art and to provide a shuttle printer capable of high-speed printing with a simple structure.

[0005]

In order to achieve the above object, the invention according to claim 1 arranges a plurality of unit printing mechanisms for advancing and retracting the printing pins in a row, and the printing pins are used as a recording medium. In a shuttle printer configured to drive printing while reciprocatingly swinging in a direction intersecting with the feeding direction of the printing pin, a support member having a guide hole for guiding at least a tip end portion of each printing pin is provided in the column direction. Is configured to be capable of reciprocating rocking along, and at the time of reciprocating rocking of the support member, at the edge of the portion of the guide hole near the base of the print pin,
One side surface of the tip portion of the print pin is laterally pressed, and the other side surface of the tip portion is not in contact with the diagonal edge of the guide hole or is not laterally pressed and the print pin Is to set the diameter and length of the guide hole so as to bend in the column direction.

The invention described in claim 2 is the same as claim 1
In the shuttle printer described above, the displacement amount along the longitudinal direction of the print pin between the print pin tip position at the center of the amplitude of the reciprocating swing and the print pin tip position at the maximum amplitude is within 0.03 mm. To be set to.

[0007]

[Embodiments] Next, embodiments embodying the present invention will be described. FIG. 1 is a side sectional view of a shuttle printer 1, and FIG. 3 is a perspective view of a print head 2, respectively. The shuttle printer 1 of the present invention is arranged between a cover upper body 4 and a cover lower body 5 arranged on an upper portion of a frame 3. The printing is performed on the lower surface of the recording medium 7 such as a sheet of paper which is transported in the direction of arrow A in FIG. 1 by the driving roller 6a and the pressing roller 6b in the sheet feeding mechanism 6 provided in the sheet path. A print head 2 which will be described later in confrontation with a substantially trapezoidal platen 8 fixed to the lower surface of the cover upper body 4.
Are arranged, and the print pins 13 of the unit print mechanism 12 in the print head 2 are arranged in a line in a direction orthogonal to the transfer direction of the recording medium 7. The print pins 13 have a predetermined amplitude (eight dots). (Amplitude) while swinging left and right along the array direction, it projects toward the lower surface of the platen 8 to print on the surface of the recording medium 7 via the ink ribbon, and the recording medium 7 thereafter is of the rotary type. After being cut to a predetermined length by the cutting means 9, a plurality of rubber projections are ejected to the outside of the machine by the ejection roller 10 protruding radially.

The basic structure of the print head 2 of this embodiment is as follows.
As shown in FIGS. 2 to 6, a base body 11 made of a metal and having an upward U-shaped cross section is disposed so as to face each other in the base body 11 and is orthogonal to the feeding direction of the print medium 7. Two
A plurality of unit printing mechanisms 12 arranged in rows, a swingable support member 14 for guiding and supporting a midway portion of the print pin 13 in each unit printing mechanism 12, and this support member 14
And a swinging mechanism 15 for swinging the print medium 7 back and forth in a direction orthogonal to the feeding direction of the print medium 7.

The base body 11 which is long in the direction orthogonal to the feeding direction of the recording medium 7 is made of metal such as aluminum alloy, the support member 14 is made of synthetic resin such as PBT, and the support member 14 is As will be described later, it is integrally formed with a cover body 16 which is attached with a screw so as to cover the upper surface of the base body 11. A plurality (28 in the embodiment) of the unit printing mechanisms 12 are provided on the vertical side plate 1 which is relatively opposed to the base body 11.
1a and 11a are arranged alternately (in a zigzag shape) in a direction orthogonal to the feeding direction of the recording medium 7 along the longitudinal direction of the recording medium 7, and the main frame 21a of each unit printing mechanism 12 is provided on the inner surface of each vertical side plate 11a. The back surface is brought into contact with and fixed with screws 17 or the like. Therefore, 14 unit printing mechanisms 12 are arranged for each vertical side plate 11a, and a plurality of printing pins 13 are arranged in a line in plan view (see FIG. 3).

As shown in FIG. 6, each unit printing mechanism 12 has a vertically elongated piezoelectric element 18 in which a plurality of rectangular piezoelectric ceramics each having a thickness of about 100 microns are laminated, and a tip of the piezoelectric element 18. A drive mechanism 19 mounted on the upper end of the piezoelectric element 18 for enlarging the expansion / contraction motion of the piezoelectric element 18 and transmitting the expanded / contracted movement to the print pin 7, and a generally upward upward side view supporting the drive mechanism 19 and the piezoelectric element 18. The U-shaped support frame 21 is made of a material having a small linear expansion coefficient, such as a U-shaped iron or nickel alloy (Invar alloy).

When charged by applying a voltage, the piezoelectric element 1
Numeral 8 extends in the laminating direction (longitudinal direction) and contracts when discharged. Since the piezoelectric element 18 shrinks as the temperature rises, the temperature compensator 20 having a positive temperature expansion characteristic for correcting the temperature is inserted between the lower end of the support frame 21 and the rear end of the piezoelectric element 18, Stick with an adhesive.

The drive mechanism 19 has a substantially triangular arm 22 in side view formed by brazing the base of a printing pin 13 having an appropriate length (50 mm in the embodiment) to the tip, and the support frame 21.
Of the main strut portion 21a in the longitudinal direction rearward in parallel with the first plate spring and the second plate spring, and a rigid connecting portion that connects the tip ends of the two plate springs to each other. The spring body 23 and the four-node link member 24 are fitted and fixed to the base end of the arm 22 by brazing or the like. The base end of the first leaf spring is connected to the main strut 2
While being brazed and fixed to the side surface of 1a, the base end portion of the second leaf spring is also fixed to the movable element 25 that comes into contact with the front end surface of the piezoelectric element 18 in a pressed state by brazing or the like.

The four-node link mechanism member 24 made of an elastic material such as a spring plate is provided on the other side of the mover 25 and the support frame 21.
Of the four-node link mechanism member 24 is provided so as to straddle the sub strut portion 21b in FIG. Then, the left and right wide side plates are fixed to the front and back side surfaces of the auxiliary column portion 21b and the front and back side surfaces of the mover 25 by spot welding (also possible by brazing), and when the piezoelectric element 18 expands and contracts by voltage application, it is a four-section link. The left and right wide side plate portions of the mechanism member 24 are elastically deformed into a parallelogram shape in a side view and positionally fixed.
The movable element 25 is configured to be movable in parallel along the longitudinal direction of b.

Then, at a predetermined timing, each piezoelectric element 1
In order to transmit a driving voltage signal from a control device (not shown) of the shuttle printer 1 so that the printer 8 operates, a pair of leads are electrically connected to the printed board 26 on the outer surface of the bottom plate portion of the base body 11. The parts 27 and 27 are provided. With this configuration, during the printing operation, when the piezoelectric element 18 extends along the longitudinal direction by the application of voltage, the rotation center is a substantially midway portion of the first plate spring fixed to the main support column 21a. As described above, the spring body 23 is oscillated and displaced, and the displacement amount is magnified by the arm 22 via the connecting portion, and the print pin 13
Is advanced toward the lower surface of the platen 8 and stamped on the surface of the recording medium 7 via the ink ribbon fed from the ink ribbon cartridge 28 mounted on the cover upper body 4.

Next, the structures of the support member 14 and the swing mechanism 15 will be described with reference to FIGS. The support member 14 includes a pair of flexible columns 30 and 30 projecting upward from the cover body 16 that covers the upper surface of the base body 11,
The main guide piece 31 is integrally connected between the upper ends of the pair of columns 30 and 30 along the longitudinal direction of the platen 8, and the central portion of the cover body 16 that covers the upper surface of the base body 11 is Groove holes 32 are formed in which the print pins 13 projecting in a row are inserted, and a pair of flexible columns 30, 30 is formed from both ends of the cover body 16 (both longitudinal ends of the groove holes 32).
Is integrally projected upward.

Further, the main guide piece 31 and the plurality of flexible auxiliary guide pieces 33 for connecting the upper and lower midway portions of the pair of columns 30 and 30 to each other have a fixed interval (2.8 mm in the embodiment). ) Are provided with guide holes (not shown) for slidably guiding and supporting the print pins 13 arranged in a line. It should be noted that both ends of each auxiliary guide piece 33 in the longitudinal direction are rotatably connected to the support columns 30 via connecting pins 34, respectively.

Next, the swing mechanism 15 will be described with reference to FIGS.
7 and FIG. 7. A connecting block 37 having a horizontal pin 36 horizontally protruding toward the upstream side in the transfer direction of the recording medium 7 is fixed to a support block 35 at the central portion in the longitudinal direction of the side surface of the main guide piece 31 with a screw 38. To do. Then, the base end of the crank arm 40 pivotally connected to the lateral pin 36, which is a swing connection portion between the support member 14 and the swing mechanism 15, is pivotally connected to the bearing 4 in the frame 3.
1 is rotatably mounted on an eccentric rotor 39 which is rotatably supported via a shaft 1, and the eccentric rotor 39 having a single swing amplitude amount e moves in a fixed direction via a swing motor 42 and a speed increasing transmission gear mechanism 43. It is configured to be rotationally driven.

A linear encoder as a sensor means for controlling the print timing is provided near the support member 14. That is, as shown in FIGS. 1 to 3, a long sensor piece 44 is arranged on one side of the main guide piece 31 along the longitudinal direction thereof, and both ends of the sensor piece 44 have the pair of columns 30, It is attached to a bracket 45 which is detachably attached to the side surface of 30. The sensor piece 44 is provided with a forward slit portion 46a composed of eight slits for printing timing and a backward slit portion 46b also composed of eight slits. Light transmissive detector 4 such as photo interrupter
Place 7.

Next, the printing operation will be described. When a printing command is issued, the recording medium 7 is moved by the paper feeding mechanism 6 in the direction of arrow A in FIG. On the other hand, since the swinging motor 42 rotates and the eccentric rotor 39 rotates in a fixed direction via the speed-increasing transmission gear mechanism 43, the main guide piece 31 which is the support member 14 via the crank arm 39 and the lateral pin 36 It reciprocates in the C and D directions of FIGS. 2 and 3 about the bases of the pair of columns 30 and 30. Therefore, one side surface of each print pin 13 on the tip side is a guide hole 31 a in the main guide piece 31.
Upon receiving lateral pressure on the side edge of the print pin 13 (see FIGS. 8 and 9) close to the base end side, each print pin 13 bends left or right around the base end. The timing for starting printing is, for example, when the main guide piece 31 reverses from the swinging end in the C direction and starts moving in the D direction.

Then, when a pulse voltage is applied to the piezoelectric element 18 in the predetermined unit printing mechanism 12 based on the dot pattern data developed into the dot pattern corresponding to the character of the input printing data, the printing pin 13 The dots can be momentarily projected in the direction of the platen 8 and dot-printed on the surface of the recording medium 7 via the ink ribbon. In this way, dots are printed one after another at a predetermined printing timing while the print pin 13 moves in the C and D directions. Next, when the main guide piece 31 reaches the swing end in the D direction, the paper feed mechanism 6 is intermittently operated to move the recording medium 7 by one dot in the line feed direction, and then dot printing is performed in the same manner as described above. To execute.

In these cases, when the main guide piece 31 comes to the right swing end or the left swing end, the tips of the respective printing pins 13 which are largely curved are located on the side surface or the side edge of the guide hole 31a in the main guide piece 31. The diameter Do and the length dimension E of the guide hole 31a and the support member 14 are provided in order to prevent the twisting.
The maximum value of the swinging piece amplitude amount a of the main guide piece 31 is set to a predetermined value.

In this embodiment, the entire length (from the mounting portion of the print pin 13 to the arm 22 to the print pin 13 in a straight line state)
Distance to the tip) H1 = 50 mm, diameter do = 0.2
The total amplitude of the tip of each printing pin 13 of 9 mm is 3.1 m
The support member 14 is swung so as to be m (amplitude a = 1.05 mm), and the diameter Do = 0.31 mm of the guide hole 31a in the main guide piece 31 of the support member 14.
And the length dimension E is set to 1.0 mm.

FIG. 9A shows the positional relationship between the tip of the print pin 13 and the guide hole 31a when the one-sided amplitude a of the print pin 13 is small, and FIG. 9B shows the tip of the print pin 13. 3 shows the positional relationship between the tip of the print pin 13 and the guide hole 31a when the one-sided amplitude amount a is the maximum value. That is, FIG.
As shown in (b), the one-sided amplitude amount a at the tip of the print pin 13
Is the maximum value, one side surface of the print pin 13 receives lateral pressure at the side edge of the guide hole 31a near the base end side of the print pin 13, and the tip side of the print pin 13 is inclined at an angle θ.
At the same time, the other side surface of the print pin 13 comes into contact (abuts) with the edge of the guide hole 31a on the front end side of the print pin 13.
The condition to be set is that the print pin 1 parallel to the hole surface of the guide hole 31a.
Assuming that the diameter of 3 is substantially equal to the diameter do of the print pin 13, tan θ = (Do-do) / E. When the inclination angle θ becomes larger than the above condition, the printing pin 13
Since the other side surface receives lateral pressure in the opposite direction at the edge (the edge at the diagonal position) on the tip side of the print pin 13 in the guide hole 31a, the print pin 13 bends in the guide hole 31a. The sliding frictional force between the side surface of the platen and the guide hole 31a is extremely increased, and the print pin 13 cannot smoothly project toward the surface of the platen 8.

When the one-sided amplitude amount a is small as shown in FIG. 9A, one side surface of the printing pin 13 receives side pressure at the side edge of the guide hole 31a near the base end side of the printing pin 13 to print. The tip side of the pin 13 is inclined at an angle θ. Further, the print pin 13 is curved as shown in FIG. In this case tan
Under the condition of θ <(Do-do) / E, the other side surface of the print pin 13 does not come into contact with the edge of the guide pin 31a on the leading end side of the print pin 13 (the edge at the diagonal position). The moving printing pin 13 has a reduced sliding friction resistance against the guide hole 31a, so that the printing pin 13 can be smoothly printed at high speed without breakage accident.

Further, when the main guide piece 31 swings to the left and right, a lateral concentrated load acts on the tip side of the printing pin 13 due to the lateral pressure from the guide hole 31a, and the cantilever beam in the material mechanics. The print pin 13 is generally bent in a curved shape as when a load is applied to the tip (or when the tip of the cantilever is forcibly displaced by a predetermined distance) (see FIG. 8). Then, as described above, the printing pin 1 curved by receiving the lateral pressure is more than the position of the tip of the printing pin 13 having the length H1 in the linear state where the lateral pressure is not received (see the chain double-dashed line in the figure).
The position of the tip of 3 is moved away from the surface of the platen 8 by a certain amount. That is, as shown in FIGS. 9A and 9B, the print pin 1 at the center position of the amplitude of the reciprocating swing.
3 The tip position of the print pin 13 at the maximum amplitude is deviated to the base end side of the print pin 13 by the displacement amount u along the longitudinal direction of the print pin 13 with respect to the 3 tip position. When this displacement amount u is large, the printing pin 13 is driven by the unit printing mechanism 12 at the time of printing to move the printing pin 13 to the platen 8.
Even if the recording medium 7 on the surface of the platen 8 and the tip of the print pin 13 are too large, the printing gap between the recording medium 7 and the tip of the print pin 13 becomes too large, and the impact force (printing force) due to the print pin.
Is insufficient, the print quality is deteriorated, and when the print quality is severe, the dot is not printed. To avoid such inconvenience,
In this embodiment, the displacement amount u is set within 0.03 mm. As described above, when the displacement amount u is set within the predetermined value, the impact force is not insufficient and the print quality is not deteriorated.

Moreover, since the swing amplitude of the printing pin 13 is about one character, which is small, there is an effect that the inertial force when swinging can be small. Further, in the present embodiment, it is assumed that one printing pin 13 can print 8 dots in the width direction (print digit direction) of the recording medium 7 within 2.8 mm, whereby Roman letters, numbers, katakana ( The above character types are referred to as ANK).

At this time, the distance H2 from the tip of the print pin 13 to the horizontal pin 36 is defined as the total length H of the print pin 13.
Set within 30% of 1. In this embodiment,
The position of the horizontal pin 36 is the same as that of the printing pin 13 having a total length of 50 mm.
Is preferably within 15 mm from the tip of the
Within m is more preferable. In this way, the horizontal pin 3 which is the point of action for transmitting the rocking force from the rocking mechanism 15 to the support member 14.
By bringing the height position of 6 closer to the tip side of the print pin 13, the difference between the total swing amount of the main guide piece 31 of the support member 14 and the actual swing amount of the end of the print pin 13 is reduced. Less. Therefore, as compared with the case where the position of the horizontal pin 36 is closer to the base end of the print pin 13, the position of the horizontal pin 36 is set closer to the front end of the print pin 13 as in this embodiment. In order to realize the actual total swing amount of the end of the printing pin 13, the manufacturing accuracy of the eccentric amount of the eccentric rotor 39 and the mounting accuracy of the crank arm 40, the eccentric rotor 39, and the lateral pin 36 are extremely strictly controlled. You don't have to. In addition, the swing mechanism 15 by swinging the support member 14
Since the reaction force against is also reduced, the speed increasing transmission gear mechanism 43
Can be formed compactly, and the driving horsepower of the swing motor 42 can be reduced.

Further, since the print pins 13 arranged in a line are simultaneously swung with a constant amplitude, a pair of left and right flexible columns 30, 30 and the tips of the columns 30, 30 are connected. Gate-shaped support member 1 including a main guide piece 31
4 can be swung right and left, and the inertial force can be small, so that the speed increasing transmission gear mechanism 43 can be formed compactly,
There is an effect that the driving horsepower of the swing motor 42 can be small.

In order to swing the support member 14 to the left and right, an eccentric cam that contacts the side surface of the driven portion such as the lateral pin 36 is rotated in a fixed direction by the speed increasing transmission gear mechanism 43 and the swinging motor 42. On the other hand, the driven portion and the eccentric cam may be connected by a biasing spring so as not to separate from each other. In addition, in each of the above-described embodiments, the horizontal pin 36 may be provided at the location of the one column 30.

[0030]

As described above, according to the invention described in claim 1, a plurality of unit printing mechanisms for moving the printing pins forward and backward are arranged in a line, and the printing pins are set in the feeding direction of the recording medium. In a shuttle printer configured to drive printing while reciprocally swinging in an intersecting direction, a support member having a guide hole for guiding at least a tip portion of each printing pin is reciprocated along the column direction. When the support member is reciprocally rocked, one side surface of the tip portion of the print pin is laterally pressed by the edge of the portion of the guide hole that is closer to the base portion of the print pin when the support member reciprocates. The other side surface is not in contact with the diagonal edge of the guide hole, or the diameter and length of the guide hole are set so that the print pin bends in the column direction without being pressed laterally. To set That.

Therefore, since the support member which can be swung in the row direction is only swung while guiding at least the tip ends of the plurality of printing pins arranged in a line through the guide holes, the structure of the support member is constituted. Is extremely simple and the manufacturing cost can be reduced. The diameter and length of the guide hole are
When the support member swings back and forth, one side surface of the tip of the print pin is laterally pressed by the edge of the portion of the guide hole that is closer to the base side of the print pin, and the other side surface of the tip is in the guide hole. Since the print pins are bent in the row direction without being in contact with or diagonally pressed against the edge at the diagonal position in, the sliding friction force received by each print pin at the guide hole is reduced. However, since twisting does not occur between the print pin and the guide hole, there is an effect that high-speed printing can be executed lightly.

The invention described in claim 2 is the same as claim 1
In the shuttle printer described above, the displacement amount along the longitudinal direction of the print pin between the print pin tip position at the center of the amplitude of the reciprocating swing and the print pin tip position at the maximum amplitude is within 0.03 mm. Therefore, in addition to the action and effect of the invention described in claim 1, the printing gap between the tip of all the printing pins and the recording medium on the platen surface side at the maximum amplitude does not become extremely large. Therefore, it is possible to reliably prevent the occurrence of printing defects due to insufficient impact force during printing.

[Brief description of drawings]

FIG. 1 is a side sectional view of a shuttle printer.

FIG. 2 is a plan view taken along line II-II of FIG.

FIG. 3 is a perspective view of a main part of a print head.

FIG. 4 is a partially cutaway front view of the print head.

5 is a view taken along the line VV of FIG.

FIG. 6 is a perspective view of a unit printing mechanism.

7 is a front view of the swing connecting portion and the swing mechanism taken along the line VII-VII in FIG.

FIG. 8 is an operation explanatory view showing a positional relationship between the print pin and the main guide piece.

FIG. 9A is an explanatory diagram showing a relationship between a guide hole and a print pin when the amount of amplitude is small, and FIG. 9B is a diagram showing a relationship between the guide hole and a print pin when the amount of amplitude is maximum.

[Explanation of symbols]

 1 Shuttle Printer 2 Printing Head 7 Recording Medium 8 Platen 13 Printing Pin 14 Supporting Member 15 Swing Mechanism 16 Cover Body 22 Arm 30 Strut 31 Main Guide Piece 31a Guide Hole 32 Groove Hole 33 Auxiliary Guide Piece 36 Side Pin 39 Eccentric Rotor 40 Crank arm 42 Swing motor 43 Speed-up transmission gear mechanism

Claims (2)

[Claims] 1. A structure in which a plurality of unit printing mechanisms for moving a printing pin forward and backward are arranged in a row, and printing drive is performed while reciprocally swinging the printing pin in a direction intersecting a feeding direction of a recording medium. In the shuttle printer configured as described above, a support member having a guide hole that guides at least the tip of each of the print pins is configured to be capable of reciprocating swing along the row direction, and when the support member reciprocally swings, At the edge of the portion near the base of the print pin in the guide hole, one side surface of the tip end of the print pin is laterally pressed, and the other side surface of the tip end with respect to the diagonal edge of the guide hole. A shuttle printer characterized in that the diameter and length of the guide hole are set so that the printing pin bends in the column direction without being contacted or pressed laterally. 2. The displacement amount along the longitudinal direction of the print pin between the print pin tip position at the center of the amplitude of the reciprocating oscillation and the print pin tip position at the maximum amplitude is within 0.03 mm. The shuttle printer according to claim 1, wherein the shuttle printer is set.