JPH0321968Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) This invention relates to a printer that prints on printing paper on a platen while moving a carriage along the platen, and particularly relates to its carriage drive device. be.

(Prior Art) In a conventional printer, for example, a driving pulley and a driven pulley are each rotatably supported at fixed positions on both the left and right ends of a frame, and a part of a belt suspended between both pulleys is fixed to a carriage. In some printers, the drive pulley is rotated to move the print head along with the carriage along the platen each time a print head on the carriage performs a printing operation for one character.

(Problem that the invention aims to solve) However, in the above printer, it is possible to accurately move the print head to the desired print position while preventing the belt from becoming loose or overly tensioned and ensuring a long movement range. In order to prevent the belt from falling off the pulleys, it is necessary to accurately set the position of each pulley and securely install each pulley in that position. It becomes necessary to increase manufacturing precision. There is a problem in that this leads to a rise in manufacturing costs.

Structure of the invention (Means for solving the problems) In order to solve the above problems, in this invention, the printing head 58 is placed and the platen 3
A carriage 55 movably arranged along the
and a carriage drive mechanism B that applies a force for moving the carriage 55 along the platen 32, and prints on printing paper on the platen 32 while moving the carriage 55 along the platen 32. The carriage drive mechanism includes a large-diameter drive pulley 82 arranged at one end of the carriage movement range and rotationally driven by the drive motor 78, and a large-diameter drive pulley 82 arranged on the frame 10 of the printer at the other end of the carriage movement range. A support member 85 is disposed movably along the support member 85, two small-diameter driven pulleys 89 are rotatably supported on the support member 85, and one of the pulleys 82, 89 is suspended between the A belt 91 fixed to the carriage 55 at the
and a biasing member 92 disposed between the support member 85 and the frame 10 in order to bias the driven pulley 89 to move away from the drive pulley 82 together with the support member 85. While maintaining the parallelism of the belt 91, the biasing member 9
Tension is applied to 2.

(Function) With the above configuration, this invention can reliably prevent the belt from falling off from each pulley, and there is no need to set the mounting position of the driven pulley accurately, thus keeping manufacturing costs low. In addition, not only can the rotational motion of the drive pulley be reliably converted into the movement of the carriage to accurately move the print head to the desired printing position, but also the driven pulley's small diameter allows its range of movement to be extended. .

(Example) An example embodying this invention will be described below with reference to the drawings.

As shown in Figures 2 and 3, the printer case 9
is formed of a synthetic resin material in the shape of a box with a bottom, and a frame 10 for a print mechanism is disposed on the rear side thereof. The frame 10 is formed of a synthetic resin material into a substantially box-like shape with a bottom, and on both the front and rear sides of the frame 10, reinforcing parts 12 and 13 are formed in the bottom part 11, which extend parallel to each other and have a rectangular cylindrical shape. Each of the reinforcing portions 12 and 13 is provided with a large number of ribs (not shown) that integrally connect the front and rear opposing inner wall portions.

Left and right side walls 10a, 10b of the frame 10
A platen 3 is located at the rear of the frame 10 between
2 is rotatably supported.

The frame 10 is located below the platen 32.
A guide member 40 for guiding the printing paper from the rear of the platen 32 toward the front is integrally formed on the platen 32 . A pair of through holes 41 facing each other are bored in both side walls 10a and 10b below the front of the platen 32, and a guide rod 42 is provided below the front of the platen 32. Shaft portions 42a having a smaller diameter than the through hole 41 are protruded from both left and right ends of the guide rod 42, and each of the shaft portions 42a
are loosely inserted into each of the through holes 41.

As shown in FIG. 2, below each of the through holes 41, a rotary lever 43 is rotatably supported at the lower end by a pin on the outer surface of both side walls 10a, 10b, and at its upper end, a screw 44, etc. It is rotatably connected to the guide rod 42. Therefore, the guide rod 42 can rotate about the lower end support point of each rotating lever 43, and can move toward and away from the platen 32 as the guide rod 42 rotates.

A guide portion 54 extending along the front reinforcing portion 12 is formed on the rear side of the front reinforcing portion 12 . Further, a carriage 55 is attached to the guide rod 42.
is movably inserted and supported in a shaft cylinder portion 56 at the rear thereof, and a guide piece 57 formed to protrude in front thereof is engaged with the upper surface of the guide member 54 . A print head 58 for printing characters in a dot matrix is placed on this carriage 55.
Its nose portion is disposed opposite to the platen 32.

As shown in FIG. 3, a ribbon cassette 61 having an endless ink ribbon 60 is disposed on the front reinforcing part 12, and a portion of the ribbon 60 is disposed between guide parts protruding rearward at both left and right ends of the ribbon cassette 61. part is exposed under tension. This exposed ribbon portion is located between the print head 58 and the platen 32. Left and right side walls 1 of the frame 10
Attachment recesses 63 are formed in 0a and 10b, and a pair of engagement pieces 62 that can be engaged with and disengaged from each attachment recess 63 are provided protrudingly on both left and right sides of the ribbon cassette 61. Based on this, the ribbon cassette 61 is locked and held on the frame 10.

As shown in FIGS. 4 and 5, a pair of gear-shaped collection rollers 6 are located in the right side of the ribbon cassette 61.
4 and 65 are rotatably housed. and,
One roller 64 is rotated in one direction in conjunction with the reciprocating movement of the carriage 55, and
By following the rotation of the other roller 65,
The used ink ribbon 60 held between both rollers 64 and 65 is collected into the cassette 61 from the right guide section, and the ribbon 60 inside the cassette 61 is pulled out from the left and right guide sections. .

Next, a drive mechanism for driving the platen 32, carriage 55, etc. will be explained.

As shown in FIGS. 1 and 4, on the lower right side of the frame 10, there is a support member 70 formed by bending a metal plate, and two screws 71 are attached at the left edge of the support member 70.
and its supporting member 70
A mounting piece 72 protruding from the front side of the frame 10 is fixed to the frame 10 by the screw 19 shown in item 1. An upright portion 7 formed at the rear of this support member 70
A drive motor 74 for driving the platen is mounted on the outer surface of 3, and a drive gear 75 located inside the upright part 73 is attached to the motor shaft passing through the upright part 73.
is fixed.

A large-diameter intermediate gear 76 that meshes with the drive gear 75 and the platen 3 are provided on the inner surface of the upright portion 73.
A small-diameter intermediate gear 77 that meshes with the driven gear 36 fixed to the drive gear 2 is supported so as to be rotatable together on the same axis. Therefore, as the drive motor 74 rotates in the forward and reverse directions, the platen 32 is rotated in the forward and reverse directions via the respective gears 75 to 77 and 36.

Note that the drive motor 74 and each gear 36, 75
77 and the like constitute a platen drive mechanism A.

A flat drive motor 78 for driving the carriage 55 and collecting the used ribbon 60 is disposed on the lower surface of the center of the support member 70;
A small-diameter drive gear 79 is fixed to a motor shaft that penetrates the support member 70 and projects upward. A support shaft 80 is protruded from the support member 70 adjacent to the drive gear 79, and its upper end is inserted into a support piece 80a protruding from the outer surface of the frame 10. A large-diameter intermediate gear 81 that meshes with the drive gear 79 and a large-diameter toothed drive pulley 82 are supported on this support shaft 80 so as to be integrally rotatable.

On the other hand, as shown in FIGS. 2 and 3, a housing recess 83 is formed at the bottom left side of the frame 10, and a pair of guide grooves 84 extending in the carriage movement direction are formed on the bottom surface of the recess 83. are formed at predetermined intervals. Further, on the right side of each guide groove 84, a mounting groove 84a is formed which is connected to each guide groove 84 and has a width larger than that of each guide groove 84. The accommodation recess 8
A support plate 85 is accommodated in the interior of the frame 10 so as to be movable in the direction of movement of the carriage, and the lower surface of the support plate 85 has protrusions 86a penetrating through each of the mounting grooves 84a and disposed below the frame 10; Projection 86a
is connected to the support plate 85, and the guide groove 8
A pair of guide pieces 86 are provided in a protruding manner and include a guide portion 86b that can move along the guide portion 4 and has a width smaller than that of the protrusion 86a.

Further, a pair of support shafts 88 are protruded from the upper surface of the left side of the support plate 85 at a predetermined interval in the front and rear, and a small-diameter driven pulley 89 is rotatably fitted onto each support shaft 88 . On the other hand, an opening 8 in the left side wall 10a of the frame 10 communicates with the housing recess 83.
7 is formed.

A toothed belt 91 is hung in parallel between the large-diameter drive pulley 82 and the two small-diameter driven pulleys 89, and a portion of the belt 91 is fixed to the carriage 55. . Therefore, as the drive motor 78 rotates forward and backward, each gear 7
9, 81, the print head 58 with the carriage 55 via the pulleys 82, 89 and the belt 91.
is moved back and forth from side to side. Furthermore, as shown in FIG. At the same time, each driven pulley 89 is urged to move leftward. Therefore, the plate spring 92 applies tension to the belt 91.

Also, the spring force of this plate spring 92 causes the belt 9 to
1 is under tension, the support plate 85
In this state, each of the driven pulleys 89 is disposed within the opening 87, and its upper end is close to and opposite to a drop-off prevention surface 90 formed on the upper inner surface of the opening 87. , each driven pulley 89 is prevented from falling off from each support shaft 88. The drive motor 78, gears 79, 81, drive pulley 82, etc. constitute a carriage drive mechanism B.

On the drive pulley 82, the support shaft 80 has an intermediate gear 100 that rotates together with the pulley 82.
is provided, and on the intermediate gear 100, a link lever 101 is swingably supported on the support shaft 80 at its base end. The distal end of this linking lever 101 is formed into a forked shape, and an operating shaft 103 is rotatably supported at the distal end portion 102 of the interlocking lever 101 . Further, a transmission gear 104 is integrally formed at the lower end of the operating shaft 103 and is constantly meshed with the intermediate gear 100. Then, the tip portion 102
The clamping force provides resistance to rotation of the operating shaft 103.

As shown in FIGS. 1 and 5, a large-diameter ribbon drive gear 106 is rotatably supported on the upper surface of a bent portion 105 formed at the front part of the support member 70, and is the one collection roller 6
The fitting protrusion 1 is removably fitted into the hole of the shaft portion of 4.
07 is formed. Two intermediate transmission gears 108 and 109 having different diameters are rotatably supported on the bent portion 105, and are always in mesh with the drive gear 106. Furthermore, the bent portion 105
A small-diameter intermediate transmission gear 110 that constantly meshes with one of the intermediate transmission gears 108 is rotatably supported above. Then, based on the swinging of the link lever 101 as the moving direction of the carriage 55 is changed, the transmission gear 104 on the operating shaft 103 is selectively engaged with the intermediate transmission gear 109 and the intermediate gear 110. ing.

That is, when the carriage 55 moves to the right, the link lever 101 is placed in the position shown in FIG.
Therefore, the intermediate gear 81, the driving pulley 82, and the intermediate gear 100 are integrally rotated in the clockwise direction in FIG. is transmitted to the drive gear 106 via an intermediate gear 109 . As a result, the gear 106 is rotationally driven in the counterclockwise direction in FIG. At the same time, the unused ribbon 60 is pulled out from the cassette 61.

On the other hand, when the rotation direction of the drive motor 78 is switched and the moving direction of the carriage 55 is changed from right to left, the drive motor 78 moves the intermediate gear 81, drive pulley 82,
The rotational direction of intermediate gear 100 is switched counterclockwise in FIG. At the time of this switch,
Based on the rotational resistance of the linking lever 101 with respect to the operating shaft 103, the linking lever 101, the operating shaft 103, and the transmission gear 104 are integrally swung counterclockwise in FIG. 1 about the support shaft 80. The transmission gear 104 is switched from the intermediate gear 109 to the intermediate gear 110 and engaged therewith.

After that, the driving pulley 82, the intermediate gear 100
etc. are continuously rotated in the counterclockwise direction in FIG. As before, the ribbon 60 is rotated in the counterclockwise direction in FIG.

Further, when the direction of carriage movement is changed from left to right, the link lever 101 is swung in the same manner, resulting in the state shown in FIG. 1.

As shown in FIG. 5, the lower surface of the notch recess 10c formed on the front lower surface of the frame 10 is disposed close to the upper surface of the other intermediate transmission gear 109. The transmission gear 109 is prevented from coming off from the support shaft 109a. In addition, the drive gear 106 and the collection roller 6
4 etc. constitute the ribbon collection mechanism C, and the intermediate gear 100, the link lever 101,
The operating shaft 103, the gears 104, 108 to 110, etc. constitute an intermediate transmission member D.

As is clear from the above description, the platen drive mechanism A, the carriage drive mechanism B, the ribbon recovery mechanism C, and the intermediate transmission member D are assembled as a unit on the support member 70, and in this state are attached to the frame 10. It is assembled.

Here, the assembly order of the carriage drive mechanism B will be explained in detail. The printing head 58 is placed and fixed on the carriage 55 to which a part of the belt 91 is fixed in advance, and the carriage 55 and the printing head 58 are attached to the guide rod 42. Then, the guide rod 42 is attached to the frame 10 on which the platen 32 is attached in advance.

Next, a drive motor 74 and gears 75 to 77 are attached to the upright portion 73 of the support member 70, and a drive motor 78 is attached to the lower surface of the center of the support member 70.
An intermediate gear 81, a drive pulley 82, an intermediate gear 100, a linkage lever 101, and a transmission gear 10 are attached to the support shaft 80.
Attach 4 to each. Furthermore, the support member 7
Each gear 106, 108 to 1 is placed on the bent portion 105 of 0.
Attach 10. Further, an elastic piece 160 is attached near the drive gear 75. This completes the assembly of the drive mechanism unit.

Next, the drive pulley 8 of this drive mechanism unit
The drive mechanism unit is placed on the right side of the frame 10 shown in FIGS. 1 and 2 with a part of the belt 91 of
The other part of the belt 91 is hung on 9. In this state, the support piece 80 with the support shaft 80 formed on the subframe 10
a and attach the unit to the subframe 10 using two screws 71. Subsequently, the support plate 85 is moved to the left, and the spring 92 is accommodated in the space formed between the support plate 85 and the left inner wall of the accommodation recess 83.

At this time, the driven pulley 89 is disposed within the opening 87, and the upper end thereof is held in a state facing the fall prevention surface 90 by the biasing force of the spring 92, and the belt 91 is held by the biasing force of the spring 92.
Tension is applied to the In addition, the print head 58
is disposed between the front and rear sides of the belt 91, and its lower portion projects downward from the belt 91.

The above operations complete the assembly of the print mechanism unit including the carriage drive mechanism B.

Now, when connecting a printer configured as described above to, for example, a Roman word processor and printing character data stored in the word processor, first turn on the power to the printer, then insert the paper. A switch (not shown) is operated to insert a cut sheet between the platen 32 and the print head 58.

Next, when a print start switch (not shown) is operated, a predetermined drive signal is input to each drive motor 74, 78 and print head 58 via a drive circuit (not shown).

As the drive motor 78 rotates forward, the intermediate gear 81 and the drive pulley 8 are connected to each other via the drive gear 79.
2. The intermediate gear 100 is integrally rotated clockwise in FIGS. 1 and 4, the belt 91 is rotated clockwise in FIG. 1, and the print head 58 is moved rightward together with the carriage 55. During this movement, the print head 58 is operated to perform printing on the cut sheet.

When the carriage 55 moves to the right, as shown in FIG. is transmitted to the ribbon drive gear 106 via the gears 104 and 109. Therefore, the drive gear 106 is rotated counterclockwise in FIG. 1, and the printed ribbon 60 is collected into the ribbon cassette 61 by the pair of collection rollers 64 in conjunction with the movement of the printing head 58. At the same time, unused ribbon 60 is pulled out from the cassette 61.

Also, after the printing operation for one line is completed,
The drive motor 74 is rotated in the forward direction by a predetermined angle, and the platen 32 is rotated clockwise in FIG. transported upwards. Thereafter, when the drive motor 78 is rotationally driven in the opposite direction and the rotation direction of the intermediate gear 100 is reversed, rotational resistance is applied to the operating shaft 103 and the transmission gear 104 is rotated to the intermediate gear 100.
0, when the intermediate gear 100 starts rotating in the reverse direction, the transmission gear 10
4 is stopped, the transmission gear 10
4 and the linking lever 101 are swung counterclockwise in FIG. 1 about the support shaft 80. Therefore, the transmission gear 104 is separated from the other intermediate transmission gear 109 and meshed with the intermediate gear 110.

As the drive motor 78 continues to rotate in reverse, the print head 58 performs a printing operation while the carriage 55 is moved to the left. When the carriage moves leftward, the transmission gear 10
4 and the intermediate gear 110, each gear 1
00, 104, 110, and 108, the ribbon drive gear 106 is rotated counterclockwise in FIG. At the same time, the unused ribbon 60 is pulled out.

Moreover, in this embodiment, a support plate 85 as a support member is movably supported on the left side of the frame 10, and a driven pulley 89 is rotatably supported on the support plate 85, and both are connected to the drive pulley. Since a leaf spring 92 as a biasing member is provided between the support plate 85 and the frame 10 to bias the belt away from the support plate 85, the belt 91 is appropriately tensioned and does not fall off from each pulley 82, 89. In addition to being able to reliably prevent this, there is no need to accurately set the mounting position of the driven pulley. Further, the rotational movement of the drive pulley 82 can be reliably converted into the movement of the carriage 55, so that the printing head 58 can be accurately moved to a desired printing position.

Furthermore, in this embodiment, after inserting the protrusion 86a into the mounting groove 84a, the guide part 86b is moved under the frame 10 and moved along the guide groove 84. Since the protrusion 86b is disposed at the support plate 85, the support plate 85 can be easily attached to the frame 10, and the support plate 85 can be reliably prevented from falling off.

Effects of the Invention As detailed above, in this invention, a biasing member is disposed between the support member and the frame in order to bias the small-diameter driven pulley in the direction away from the large-diameter driving pulley. Since the biasing member applies tension to the belt, it is possible to reliably prevent the belt from falling off from each pulley, and the driven pulley can be easily installed, and the installation position can be adjusted easily. Precise settings are not required, thus reducing manufacturing costs. Also, since the driven pulley has a small diameter, the range of movement of the carriage can be extended, and the frame shape can be made more compact. I can do it. Furthermore, it has the excellent effect of reliably converting the rotational movement of the drive pulley into movement of the carriage and accurately moving the printing head to the desired printing position.

[Brief explanation of the drawing]

Fig. 1 is a plan view of essential parts showing an embodiment of a printer embodying this invention, Fig. 2 is an exploded perspective view of essential parts of the printer, Fig. 3 is a sectional view, and Fig. 4 shows the drive mechanism of the printer. The exploded perspective view shown in FIG. 5 is a sectional view of the drive mechanism section. In the figure, 10 is a frame, 32 is a platen, 55 is a carriage, 58 is a print head, 82
is a drive pulley, 85 is a support plate as a support member,
89 is a driven pulley, 91 is a belt, 92 is a leaf spring as a biasing member, and B is a carriage drive mechanism.

Claims (1)

[Claims for Utility Model Registration] The printing head 58 is placed and the platen 32
A carriage 55 is movably arranged along the
and a carriage drive mechanism B that applies a moving force to the carriage 55 along the platen 32, and a printer that prints on printing paper on the platen 32 while moving the carriage 55 along the platen 32, The carriage drive mechanism is arranged at one end of the carriage movement range,
a large-diameter drive pulley 82 rotationally driven by a drive motor 78; a support member 85 disposed movably along the carriage movement direction on the printer frame 10 at the other end of the carriage movement range; Two small-diameter driven pulleys 89 rotatably supported on the member 85; a belt 91 suspended between the pulleys 82 and 89 and partially fixed to the carriage 55; and the support member. 85 and a biasing member 92 disposed between the support member 85 and the frame 10 to bias the driven pulley 89 in a direction away from the drive pulley 82, and the parallelism of the belt 91 A carriage drive device for a printer, characterized in that the biasing member 92 applies tension while maintaining the tension.