JPS5912471B2 - small line printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 25 The present invention relates to a small line printer that is most suitable as a recording output machine for small office equipment such as a calculator or an electronic cash register.

Conventional small line printers include drum type printers in which a plurality of hammers 30- are used to hit the type on a continuously rotating type drum, and a drum type printer in which a plurality of type wheels are provided to strike the type on each type wheel. You can select and stop each one individually and print them all at once with a common hammer, or
Most of the type wheel type printers printed by pressing the selected and stopped type wheel itself against the platen. However, although these line printers were superior to serial printers in that they had faster printing speeds, they had a more complex structure, had more parts, and were inferior to serial printers in terms of maintenance, inspection, and economic efficiency. Therefore, the compact line printer according to the present invention has a novel configuration that eliminates the above-mentioned drawbacks.In particular, it uses a type wheel type, and selects type and presses it against the platen at the same time while the type wheel is rotating. It is characterized by a configuration for printing.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a partially broken top view of a top cover of a printer according to the present invention, FIG. 2 is a sectional view taken along a single line, FIG. 3 is a front view of FIG. 1, and FIG. It is a rear view of the same. In the figure, 10 and 11 are left and right frames, 12 is a platen rotatably supported between both frames 10 and 11, and 13
is a paper cutter 14 and an ink roll holder 15
A top cover 1, 16 that covers the top surface of the printer main body.
17 is an ink roll supported rotatably on this ink roll holder 15 around an axis parallel to the axis of the platen 12; 17 is an ink roll 16 between both frames 10 and 11;
The rotation of the motor 18 is transmitted through gears 19, 20, and 21, as shown in FIG. 2
A plurality of holders 2 are rotatably supported on a drive shaft 17 and arranged in parallel, and their free ends extend between the ink roll 16 and the platen 12.

A type wheel 23 is rotatably supported on the free end side of each holder 22, and a plurality of printed characters such as numbers and letters are formed on the circumferential surface of each type wheel 23.

Further, this type wheel 23 is always connected to the drive shaft 17 in gear, and the rotation of the type wheel 23 is completely synchronized with the rotation of the drive shaft 17. 24 is a ratchet wheel rotatably attached to each holder 22 on the drive shaft 17, and 25 is a pawl rotatably supported on the holder 22 in opposition to the ratchet wheel 24. It is a lever and is always held outside the rotational trajectory of the ratchet wheel 24 by a spring 26.

On the other hand, each holder 22 is guided by holder guides 27 and 28, and is normally held at a rest position on the ink roll side by a spring 30 stretched between the stopper 29 and the holder 22. In this state, the type wheel 23 on the holder 22 is in pressure contact with the ink roll 16, and the rotation of the type wheel 23 causes the ink roll to
6 also rotates, and ink is applied to the type on the peripheral surface of the type wheel 23. Reference numeral 31 indicates each claw lever 25 in order to push up the claw lever 25 on the holder 22 into the rotation locus of the ratchet wheel 24.
It is a trigger lever provided corresponding to the electromagnet 3.
2.

Furthermore, when each holder 22 moves to the printing position, the type wheel 23, ratchet wheel 24, and pawl lever 25 on the holder 22
The positional relationship between the two is shown in detail in FIG. 5 and FIG. 33 is a printed circuit board attached to the outside of the right frame 11, and electronic circuit components (not shown) such as a reed switch 34 and others are placed on this printed circuit board 33.

35 is a position detection gear connected to the drive shaft 17 at a rotation ratio of 1, and has a cam plate 36 having a cam recess 36a for stopping at a fixed position and a position detection gear having a number of teeth corresponding to the number of characters on the type wheel 23. A detection plate 37 is integrally provided.

Further, a permanent magnet 38 for biasing the reed switch 34 is mounted on the cam plate 36. 39 is a positioning roller whose one end is rotatably supported by the other end of an elastic piece fixed to the right frame 11, and which performs positioning by elastically engaging with the cam recess 36a on the cam plate 36; 40 is attached to the shaft of the platen 12; The paper feed gear 41, which is rotated one pitch per rotation of the position detection gear 35, is a position detection head mounted on the right frame 11 facing the position detection plate 37.

Note that 42 is a paper pan provided under the platen 12, and 43 is an ink receiver provided below the ink roll 16. The printing operation of the printer according to the present invention having the above configuration will be explained with reference to the operation explanatory diagram of FIG. 7 and the time chart of FIG. 8.

In FIG. 8, when a print command signal 4 is input from outside the printer, a motor drive signal 8 is applied to the motor 18, and the motor 18 starts rotating.

Accordingly, the drive shaft 17 also rotates, and each type wheel 2
3 rotate all at once while being in pressure contact with the ink roll 16. On the other hand, the position detection gear 35 rotates at a rotational ratio with respect to the drive shaft 17, the cam recess 36a on the cam plate 36 escapes from the positioning roller 39, and each tooth of the position detection plate 37 moves to the position detection position. 41, a timing signal 6 corresponding to the position of the type on the type wheel 23 is output from the position detector 41. Then, while the drive shaft 17 and the type wheel 23 rotate twice, the position detection gear 3
5 rotates once, and just before that, the permanent magnet 38 on the cam plate 36
energizes the reed switch 34 on the printed circuit board 33,
By closing that contact, an end signal 9 is obtained.
The motor drive signal 8 disappears due to this end signal [present], and after that, the motor 18 continues to rotate due to inertia, and the motor is rotated at the position where the positioning roller 39 is fitted into the cam recess 36a of the cam plate 36. 18 and the drive shaft 17 are stopped.
Further, the paper feed gear 40 of the platen 12 is fed by a pitch just before the position detection gear 35 completes one rotation, and the paper is fed by the rotation of the platen 12 as shown in time chart 8. Now, when a type selection command is given to each type wheel 23 from outside the printer during one printing cycle, a selection signal [F] is generated in synchronization with a signal corresponding to the type to be selected among the timing signals 6. is applied to the electromagnet 32 corresponding to that type wheel 23, energizing it.

As a result, the trigger lever 31 rotates clockwise as shown in FIG. to engage. Due to this engagement, the holder 22 is rotated in the same direction as the rotational direction of the drive shaft 17 by the rotational driving force of the drive shaft 17 against the spring 30, and moves to the printing position, as shown in the time chart 6. The wheel 23 is caused to collide with the printing paper (not shown) on the platen 12, and the selected characters are printed. At the same time or immediately before this type wheel 23 and platen 12 come into contact, the pawl lever 25
The protrusion on the side where the spring 26 is stretched is the stopper 2.
9 and rotates the pawl lever 25 clockwise, the pawl lever 25 and the pawl wheel 24 on the 1 drive shaft 17 are disengaged, and the holder 22 is stopped from the printing position by the spring 30. returned to position. Incidentally, the trigger lever 31 is activated by the electromagnet 32 as the pawl lever 25 is forcibly rotated clockwise.
When the bias is released, it is rotated counterclockwise and returns to its original position. This printing operation is performed for each type wheel 23 while the type wheel 23 rotates twice, and one line of printing is performed.

As explained above, the printer according to the present invention arranges a plurality of holders having type wheels in parallel on one drive shaft, selectively engages the holders with the drive shaft, and applies the rotational driving force of the drive shaft to type. Since the wheel is brought into contact with the platen, it is possible to print while the type wheel is rotating, eliminating the need for a means for selecting and stopping the type wheel as seen in conventional examples. It's easy. In addition, the ink roll method is used, and printing is performed using the type wheel by swinging the holder between the platen and the ink roll, making it extremely easy to apply ink when the type wheel is at rest. Since the type wheels contact the platen independently, ghosts do not occur on the printing paper surface. Moreover, since there is a sufficient distance between the type wheel and the platen at the holder rest position, it is easy to see the printed side of the printing paper. Furthermore, in this embodiment, since the trigger lever is forcibly returned to its original position by a pawl lever, a spring member for returning the trigger lever to its original position is not required. In addition, even though the motor is driven intermittently, the cam plate makes it possible to stop it in a fixed position, making it possible to accurately detect the position of type and feed paper using the platen with a simple mechanism. The effects of the invention are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway top view of the top cover of a printer according to the present invention, FIG. 2 is a sectional view thereof, and FIG.
The figures are the front view of Fig. 1, Fig. 4 is the rear view of the same, Fig. 5 is a front view of one holder showing the ratchet wheel and pawl lever engaged, and Fig. 6 is a cross-sectional view taken along the - line. , FIG. 7 is an explanatory diagram of the printing operation, and FIG. 8 is a time chart showing various signals and machine operations. In the figure, 10 and 11 are left and right frames, 12 is a platen, 1
6 is an ink roll, 17 is a drive shaft, 18 is a motor, 22
is a holder, 23 is a type wheel, 24 is a ratchet wheel, 25
is a claw lever; 29 is a stopper; 30 is a spring; 31 is a trigger lever; and 32 is an electromagnet.

Claims (1)

[Claims] 1 a frame, a platen supported on the frame, an ink roll rotatably supported on the frame around an axis parallel to the platen, and an axis parallel to the axis of the ink roll on the frame; a drive shaft rotatably supported around the drive shaft; a heater for rotationally driving the drive shaft; and a heater rotatably supported on the drive shaft, with a free end between the ink roll and the platen. a plurality of holders extending in parallel and arranged in parallel so as to be swingable between a rest position on the ink roll side and a printing position on the platen side; and a plurality of holders rotatably supported on the free end side of each of the holders. , a type wheel having a plurality of types arranged on each peripheral surface; a spring means for always holding the holder in a rest position and pressing the type wheel against the ink roll in the rest position; and a drive means. A rotation transmission means for constantly transmitting the rotation of the shaft to each type of wheel, a pawl lever rotatably supported on each of the holders, a pawl wheel fixed to the drive shaft, a pawl lever and a pawl wheel. A trigger lever is driven by an electromagnet and has one end brought into contact with the pawl lever to engage the pawl lever and the pawl wheel against the negative force of the pull spring. The holder is selectively engaged with the drive shaft by selectively driving the electromagnet, and when the holder is engaged, the rotational driving force of the drive shaft moves the holder from the rest position to the printing position against the spring means. a stopper that abuts one end of the pawl lever and releases the engagement between the pawl lever and the pawl wheel; 1. A small line printer comprising: disengagement means for returning the holder from a printing position to a rest position by means of means.