JPS5922780A - Small serial printer - Google Patents

Abstract

PURPOSE:To provide the titled printer capable of performing symbol printing of two figures or more, constituted by respectively providing plural protrusions for a figure and a symbol to a cam plate provided along the reciprocal route of a carriage in engageable relation to hammers for printing figures and the symbols. CONSTITUTION:A cam 22 is provided aong the reciprocal route of a carriage. One arm 19a of a symbol printing hammer 19 is bent to be inlaid with and inserted into a drum base stand 16 and a roller 21 is attached to a position opposed to a symbol type belt 18 in a freely rotatable manner. The leading end of the other arm 19b is confronted to a position engageable with the protrusion of the cam plate 22. A roller 23 is pivotably supported by the arm 20a of a figure printing hammer 20 in a freely rotatable manner to be opposed to a figure type belt 17. A pawl 25 is pivotably supported by the leading end of the other arm 20b in a freely rotatable manner and confronted to a position engageable with the protrusion 22c. Two or more symbols can be printed by this mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized serial printer, and more particularly to a small-sized serial printer that can print symbols and numbers, and can print symbols multiple times.

Conventional serial printing type printers place the type drum horizontally with respect to the printing paper, that is, with the rotating shaft horizontal, and serial printing is performed by the rotation, stopping, impact, and carry operations of the type drum. I was doing it.

However, this type of conventional printer requires an expensive pulse motor to drive and control the type drum and perform the printing operation.
Alternatively, a complicated latch mechanism is required to transmit intermittent power, and the overall cost tends to be high.

Therefore, in order to improve this drawback, a small serial printer is equipped with a type drum that rotates around an axis perpendicular to the digit direction of the printing paper, and a carriage that conveys the type drum in the direction of the printing digit. was proposed.

In this type of small serial printer, symbol printing and
When printing numbers, the structure was such that only one digit could be printed as a symbol.

However, the uses of calculators and other devices equipped with this type of printer continued to expand, and the need to print various types of numbers for different purposes began to emerge, leading to the emergence of printers that could print symbols of two or more digits or more. was desired.

The present invention has been made in response to the above-mentioned needs, and an object of the present invention is to provide a small-sized serial printer having a block structure capable of printing symbols of two or more digits.

In the present invention, in order to achieve the above object, a cam plate is provided along the reciprocating path of the carriage, and a type belt for printing numbers and a type belt for printing symbols are provided in the vertical direction on the type drum. A marker for printing numbers and symbols was provided with one end facing inside the type drum and the other end facing the cam plate side. structure was adopted.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Figure 1 and the following diagrams explain one embodiment of the present invention.
The figure shows the overall configuration.

The small printer according to the present invention is assembled based on a frame l. At one end of the frame 1, a motor 2, a solenoid 3 that serves as a trigger when driving a control mechanism to be described later, and a tacho generator 4 for detecting a TP multiplied signal are arranged.

The output shaft 2a of the motor 2 extends outward beyond the left side plate 1a of the frame 1, and has a pinion gear 5 at its tip.
is fixed. In addition, a rotating shaft 6 is parallel to the output shaft 2a.
is rotatably supported on the side plate 1a, and an intermediate gear 8 is rotatably supported on a shaft (not shown) between the gear 7 and the gear 7 fixed to the outer end thereof. 7 and transmits the rotation of the motor 2 to the rotating shaft 6.

As shown in FIG. 2, the rotating shaft 6 is equipped with a worm gear 9 and a T.
A tachogenerator magnet 10 for P signal detection is fixed, and the worm gear 9 is connected to a drum gear 11 to be described later.
are always engaged.

The drum gear 11 is connected to a guide shaft 12.1 as shown in FIG.
3, and a TR for detecting the TR signal is provided on the lower surface of the drum gear 11.
A drum 15 is integrally equipped.

Further, a drum base 16 is located above the carriage 14, and a drum gear 11 and a TR drum 15 are integrally connected to the carriage 14 via a shaft 16a formed in one body. It is rotatably supported on the shaft.

On the drum base 16, there is a type belt 17 for numbers on the upper side.
A type belt 18 for symbols is wrapped around the lower side, and projections 17a are formed on the back side of each type.

+8a passes through a through hole made in the drum base 16 and is fitted inside the drum base 16.

@1 As shown in Figure 1, a hammer 19 for symbol printing located on the upper side and a hammer 20 for printing numbers located on the lower side are arranged on the carriage 14 in the direction of the upper digits of the drum base 16. A shaft 14f extending upward from 14
is rotatably supported within a certain angular range.

The symbol printing hammer 19 is fitted into the drum base 16 by bending one arm 19a as shown in FIG. It can be installed freely.

The tip of the other arm 19b faces a position where it can engage with a protrusion 22b protruding inside the base of the vertical portion 22a of the cam plate 22, which is disposed along the reciprocating path of the carriage.

A roller 23 is rotatably supported on the lower surface of the tip of the arm 20a of the number printing hammer 20 extending above the drum base 16 via a shaft 24. is facing. There is a claw 25 at the tip of the other arm 20b, and as shown in FIG.
It is rotatably supported within the range of the protrusion 22.
It faces a position where it can engage with the protrusion 22c located on the lower side of b.

Note that the protrusions 22 b and 22 c have a triangular cross section, and are configured such that the tips of the arms 19 b and 20 b can ride on them from either direction when the carriage 14 is moved up or back.

On the outer edge of the horizontal portion 22d of the cam plate 22, a plurality of triangular protrusions 22e, as shown in FIG. 5, are formed in the shape of a copper mountain. As shown in FIG. 6, the tips of elastic pawls 14a protruding from one end of the carriage 14 are engaged with these protrusions 22e.

Further, as shown in FIG. 7, the cam surface 22 is rotatably supported on the rotating shaft 6 via a platen 22f protruding from the lower end, and is provided so as to be freely rotatable within a certain angular range. The spring S provides a clockwise rotational habit in FIG.

On the other hand, the reference numeral 26 indicates an ink roller case in which an ink roller 28 is rotatably supported via a shaft 27. This ink roller case 2B has an elastic claw 26.
a, and is removably engaged with a protrusion 14b provided on the carriage 14.

A spring 29 is tensioned on the carriage 14 at the mounting portion of the ink roller case 26, and this spring 29 holds the ink roller case 26 so that it does not come out, and the ink roller 28 is used for printing type and symbol printing. The type belt 18 is pressed against the type belt 18 to apply ink.

A carriage return spring 3 is attached to one end of the carriage 14.
One end of the spring 30 is connected to the other end of the spring 30. The other end of the spring 30 passes behind the platen 39 in contact with an arc-shaped guide 31 protruding from the side surface of the right side plate 1b in FIG. The carriage 14 is always fixed to the side plate 1.
A movement habit of being pulled in the b direction is given. However, if the claw 14a of the carriage is engaged with the protrusion 22e of the cam plate 22 as shown in FIG.
movement is regulated.

On the other hand, as shown in FIG. 6, a drive gear 32 meshes with the drum gear 11, and the drive gear 32 is rotatably supported on a shaft 14d extending downward from the carriage 14. At the bottom of this drive gear 32, the shaft 14d
A control lever 33 is rotatably supported on a shaft, and its rotational tendency in the clockwise direction in FIG. 6 is maintained by a spring (not shown).

The free end 33a of the control shaft 33 faces a position where it can engage with rack teeth 34a of a rack plate 34 arranged parallel to the cam plate 22 along the reciprocating path of the carriage 14.

In addition, as shown in FIG. 6, the drum gear ll also has rack teeth 3.
4a, and one end of the rack plate 34 in its width direction can be freely rotated within a certain angular range via a shaft 35, as shown in FIG. 9, with respect to the side plate 1b.

The rack plate 34 has a shaft 34b on the opposite side from the shaft 35 and protruding outside the side plate 1b of the frame, and this shaft 34b
One end of a lever 36 is rotatably connected to the lever 36 .
The lever 36 is rotatably supported on the side plate 1b via a shaft 36c in the middle thereof, and a protrusion 36a is formed upward near the other end, and this protrusion 36a is connected to the armature of the solenoid 3 It is in contact with the free end 37a of 37. Further, a spring 38 is stretched between the end of the lever 36 opposite to the shaft 34b and the upper end of the side plate 1b, giving the rack plate 34 the ability to rotate clockwise in FIG. It is being

On the other hand, a paper guide 40 is provided between the carriage 14 and the platen 39 facing the type drum, and the printing paper P is guided therethrough. A clutch gear 41 is provided on the lower surface of the side plate ib of this platen 39 in FIG. 1 at a position where it can mesh with the drive gear 32.

As shown in FIGS. 1A and 1B, the clutch gear 41 is rotatably fitted into a boss 43a of a PF (paper feed) worm 43 rotatably supported on a shaft 42. Although it can move freely in the thrust direction, it is subject to restrictions in the radial direction as described below.

The clutch gear 41 is given the habit of always moving upward by a spring 44 that is elastically loaded between the spring receiver 42a at the lower end of the shaft 42. As shown in FIG. 16, a gently sloping cam surface 41a is formed on the upper surface of the clutch gear 41, with one end being high and the other end being low.
A ratchet 41b for preventing reverse rotation, which will be described later, is formed.

Further, a PF is provided near the clutch gear 41 via a shaft 45.
A lever 46 is rotatably supported, and one end 46 of the lever 46 is rotatably supported.
A spring (not shown) maintains the rotational behavior in the direction in which b contacts the cam surface 41a.

On the other hand, the worm part 43b of the PF worm 43 is connected to the PF gear 4 formed as a crown gear as shown in FIG.
7, and the PF gear 47 is fixed to a shaft 49 that is integrated with a rubber roller 48 that sends out the printing paper P. The rubber roller 48 is provided with a pinch roller 50 that pinches the printing paper P.
are in contact with each other, and the printing paper P is sent out.

By the way, in FIG. 1, there is a leaf spring 5 on the right side plate 1b.
1 is fixed, and its bent free ends 51a, 5
1b are in positions where they can engage with protrusions 22g and 22h protruding from the ends of the cam plate 22, respectively, as shown in FIG.

By the way, the outer peripheral surface of the TR drum 15, which is integrated with the drum base 16, is coated with conductive films 52a to 5, as shown in FIG.
2c are provided separately at predetermined intervals, and a brush 53a953b whose one end is fixed to the carriage 14 side is in sandwich contact with these films 52a to 52c.

A voltage is applied to the brushes 53a and 53b from the carriage side, and as the TR drum 15 rotates, each brush 53a and 53b simultaneously contacts the same film 52a once per rotation, and a TR signal is detected. do.

Next, the operation of the printer according to the present invention configured as described above will be explained with reference to the timing chart shown in FIG.

First, when the switch is turned on and the motor rotates, the rotation is transmitted to the drum gear 11 via the pinion gear 5, the intermediate gear 8°, the rotating shaft 6, and the worm gear 9, and the drum base 16 integrated with the drum gear 11. is the first
It is continuously rotated clockwise in the figure.

Then, when the drum gear 11 rotates, the T
The R drum 15 also rotates and a TR signal is output.

Further, due to the rotation of the magnet (10) attached to the 1-rotation shaft 6, the tachogenerator 4 outputs a TP multiplied signal.

When a printing command is issued by the control circuit based on these signals, the solenoid 3 is turned on, the tip 37a of the arbuture 37 pushes down the protrusion 36a of the lever 36, and the rack plate 34 moves around the shaft 35 as shown in FIG. direction, and the rack teeth 34a side rises.

As a result, the rack teeth 34a and the drum gear 11 mesh with each other, and the free end 33a of the control lever 33 is positioned below the rack teeth 34a. That is, the free end 33 of the control lever 33
The relationship between a and the rack teeth 34a is shown in FIGS.
). Here, even if the power to the solenoid 3 is turned off, the rack teeth 34a are in contact with the free end side 33a''2 of the control lever 33, so the rack plate 34 cannot return to the horizontal state, and the rack teeth 34a and the drum gear 11 are Continue to engage.

As a result, the drum gear 11 moves forward, the carriage 14 moves forward, and the drum base 16 rotates, thereby performing a carrying motion.

Of course, at this time, the printing hammers 19 and 20 also move at the same time, and when printing the first digit, the vertical part 22 of the cam plate 22
Of the symbol printing projections 22b arranged above a, the left projection 22b shown in FIG. 5 and the arm 1 of the symbol printing hammer 19
Only the tip of the arm 9b is engaged, and the symbol printing hammer 19 is rotated counterclockwise as shown in FIG.
Since the roller 21 attached to the symbol presses the protrusion 18a on the back side of the symbol type bell 18, the selected type flies out toward the printing paper P, is pressed against the platen 39, and is printed.

When the tip of the arm 19b of the symbol printing hammer 19 passes over the protrusion 22b, the roller 21 separates from the protrusion 18a of the symbol type bell 18, and printing is completed.

However, the drum gear 11 is still meshing with the rack teeth 34a, and the carriage 14 is in the middle of being carried up.

As the carriage 14 moves up, the control lever 3
12(C), the rack teeth 34a come into contact with the stepped portion of the free end 33a, and the position shown in FIG. 12(C) is reached.
As shown in D) to (F), the rack teeth 34a and the drum gear 11 are disengaged, and the rack teeth 34a and the control lever 3 are disengaged.
The free ends 33a of 3 are engaged, and the carriage 14 no longer moves forward.

Here, if the carrying speed is high, the carriage 14 tries to move forward due to inertia, but the tip 33a of the control lever 33, which moves together with the carriage 14, hits the next rack tooth 34a, and the movement of the carriage 14 is stopped. regulate.

Further, the carriage 14 tries to be returned to the home position by the return spring 3o, but as shown in FIG. 6, the tip of the claw 14a of the carriage 14 engages with the protrusion 22e of the cam plate 22, and stops at that position. . At this time, the free end 33a of the control lever 33 and the rack tooth 34a are connected to the 12th
The state shown in figure (F) will be reached.

In other words, the control lever 33 touches the rack tooth 3 during carry-up.
4a and the drum gear 11, ensuring a carry of one digit, and preventing an overrun of the carriage 14.
When the solenoid 3 is energized, the carriage 14 starts carrying up as described above, and the right-hand protrusion 22b of the upper protrusion 22b of the cam plate 22 shown in FIG. The tip of 19b engages and prints the symbol again.

In addition, in FIG. 21, a printed example of "r985CN" is shown. When the printing of the second digit symbol is completed, the paper is fed as described later, and the printing paper is lifted to the same position as the number belt. Then, when the solenoid 3 is energized by the third digit print signal, the carriage 14 starts carrying up as described above, and the cam plate 2 shown in FIG.
The leftmost protrusion 22cl among the protrusions 22c lined up on the lower side of the vertical portion 22a of No. 2! - Arm 20 of printing hammer 20 for D character
The claw 25 attached to the tip of b engages. Since the pawl 25 is restricted from rotating counterclockwise in FIG. 17 during carry-up movement of the carriage, the hammer 20 is rotated counterclockwise in FIG. The number type belt 17 is pushed by a roller 23 provided on the lower surface, and the selected number is printed.

Thereafter, when all the numerical digits are printed in the same manner and the carriage 14 reaches the most significant digit, a protrusion formed on the shoulder of the pawl 14a of the carriage 14 and the base of the cam plate 22 as shown in FIG. 22i is engaged, and the cam plate 22 moves in the direction away from the carriage 14, as shown by the solid line in FIG.

As a result, as shown in FIG. 15(A), the leaf spring 5
15(B) -
As shown in (C), it begins to engage with the free ends 51a and 51b. As a result, the cam plate 22 is held in that position.

This is the state shown in FIG. 15(C).

In this state, the claw 14a of the carriage 14 disengages from the protrusion 22e of the cam plate 22, so the carriage 14 is pulled back to the home position by the tensile force of the return spring 30.

At this time, the free end 33a of the control lever 33 is attached to the rack plate 34.
Since the force of the return spring 30 is greater than the spring force pressing the control lever 33, the control lever 33 is repelled counterclockwise in FIG. 6 by the rack teeth 34a, preventing the carriage 14 from returning to the home position There isn't.

By the way, when the carriage 14 returns, the claw 25 attached to the tip of the arm 20b of the number printing hammer 20 touches the cam plate 2.
However, since the pawl 25 can rotate clockwise in FIG. 4 at intervals of a predetermined angle θ as shown in FIG. No printing is performed.

Note that once the claw 25 is rotated, it will not engage with the protrusion 22c thereafter, and will not stain the printing paper until it returns to the home position.

On the other hand, as shown in FIG. Since the setting is such that the arm 19b does not come into contact with the paper, no symbols are printed and the paper is not soiled.

When the carriage 14 returns to the home position.

As shown in FIG. 15(D), the protrusion 14e of the carriage 14 hits both free end sides 51a and 51b of the leaf spring 51, and the engagement between the protrusions 22g and 22h of the cam plate 22 and the bent portion of the leaf spring 51 is ensured. Once removed, the cam plate 22 is returned to its original state by a spring (not shown). Then, before printing of the next line begins, paper feeding is performed as described later, and all printing cycles for one line are completed.

Next, the paper feeding operation will be explained.

During carry-up for printing the second digit symbol mentioned above, the protrusion 14e provided on the carriage 14 engages with one end 46a of the PF lever 46 as shown in FIG. 2, and the carriage 14 is in a predetermined position. When it stops, it is disengaged.

At this time, the PF lever 46 engaged with the protrusion 14e is rotated clockwise as shown by the chain line in FIG. 2, and its one end 46b is disengaged from the cam portion 41a.

As a result, as shown in Fig. 1O (B), the spring 4
Clutch gear 41 was being pushed up against the force of 4.
is pushed up by the spring 44 and rises as shown in FIG. 10(A), and the clutch gear 41 and drive gear 32
are engaged, and the clutch gear 41 begins to rotate.

When the clutch gear 41 starts rotating, the one end 46b of the restored PF lever 46 rides on the cam part 41a and is gradually pushed down, as shown in Figure 1o CB).
The mesh with the drive gear 32 is disengaged.

During this time, the PF worm 4 is engaged with the clutch gear 41.
3 also rotates in the same direction, and PF gear 4 meshes with it.
7 is rotated, and the comb roller 48 is rotated via the shaft 49. As a result, the printing paper P held between the rubber roller 48 and the pinch roller 50 is fed half a pitch.

In this way, the printed symbol is raised to the same level as the next printed number, so that the number can be printed on the same line as the symbol. This eliminates the need for vertical movement of a drum or platen during printing, as seen in typewriters.

Note that when the paper feeding is finished and the drive gear 32 and the clutch gear 41 are separated, the tip of the arm 46b of the PF lever 46 is pressed to prevent the clutch gear 41 from moving in one direction while being reversed by the clutch spring 44. is engaged with the ratchet 46c to prevent reverse rotation.

Further, when the carriage 14 finishes printing the most significant digit and returns to the home position, the paper is similarly fed the remaining half-pitch at L7.

By the way, when printing is not performed over all digits and the carriage 14 is returned midway, a slightly different operation is required.

That is, as shown in FIG. 17, in this case, when the printing operation is performed as described above on the protrusion 16c protruding from the inner surface of the drum base 16, the roller 23 of the hammer 20 hits the protrusion 16c. , rotation of the hammer is obstructed,
Contrary to what was mentioned above, the hammer 20 does not move and the carriage 1
4, the cam plate 22 falls to the left in FIG.
The state shown in FIG. 15(C) is reached, the carriage 14 returns to the home position, and the printing cycle when not all digits are printed is completed.

In addition, when printing only the paper without performing a printing operation, when printing symbols in the first and second digits, as shown in FIG.
The printing operation is performed on the inner part of the drum base 16, and after performing a half-pitch paper feeding operation, the printing operation is performed on the inner protrusion 16c of the drum base 16 at the third digit, that is, the first digit of the number. Then, the carriage 14 is returned to the home position in the same manner as described above, and the paper is fed the remaining half-pitch, so that the paper is fed a total of l pitches.

By the way, when the printer of the present invention is installed in a calculator etc., when the calculator is turned on, the carriage 1
4 is stopped at any digit, the protrusion 16 provided inside the drum base 1e is first detected by the TR signal, TP and other signals.
For c, a printing operation is performed, the carriage 14 returns to the home position, and a reset operation is performed for the next printing.

When the carriage is stopped at the O-th and first digits, which are the home positions, the projections 22g and 22h of the cam plate 22, which are one of the means for returning the carriage 14, and the free ends 51a and 51b of the leaf spring 51 The engagement is slightly different.

That is, when the protrusion 22g of the cam plate 22 and the free end 51a of the leaf spring 51 engage, the arm 19 of the symbol printing hammer
Since the protrusion 22b is set so that the protrusion 22b of the cam plate 22 does not engage with the protrusion 22b of the symbol printing hammer 19, the digit return is performed by the tip of the arm 19b of the symbol printing hammer 19 and the protrusion 22b of the cam plate 22. , as shown in FIG. 15(B), the protrusion 22h of the cam plate 22 and the bent portion of the free end 51b of the leaf spring 51 are engaged, and the carriage 14 returns.

In this case, there is a possibility that the tip of the arm 19b of the symbol printing/XX mommy 9 will engage with the protrusion 22b, but the carriage 1
When the carriage 4 returns from a position close to the home position, the force of the return spring 30 is weak and the return speed of the carriage 14 is slow, so that the printing paper is not soiled.

Further, the protrusion 22c of the cam plate 22 that can engage with the claw 25 of the number printing handle 20 is not located near the home position, so that it does not stain the printing paper.

By the way, -L is printed on the arm 19b of symbol 19.
In the embodiment described above, nothing is provided, but the 19th
As shown in the figure, the claw 54 may be attached to be rotatable within a certain angle range, and a protrusion 22j may be provided at one end of the cam plate 22 that engages with the claw 54 when the claw 54 is rotated to the state shown by the chain line. .

Unlike the embodiments described above, if such a structure is adopted, even when the carriage is stopped at the 0th and 1st digits, it is returned.

As in the embodiment described above, the tip of the arm 19b and the protrusion 22b
There is no engagement between the two.

The carriage 14 returns to the home position, and the cam & 22
When the protrusion 22j is raised, the protrusion 22j engages with the claw 54, and the claw 54
returns to normal.

Note that the conductive film provided on the TR drum 15 is the 20th conductive film.
It is also possible to use only 52a as shown in the figure. In this case, although abrasion powder is generated in the insulating portion, insulation failure due to abrasion in the conductive portion does not occur.

Since this embodiment is configured as described above, compared to a printer that performs type selection, printing, and carry separately, printing and carry are performed simultaneously, so there is less time loss.
A printer capable of high-speed printing can be obtained.

In addition, printing is performed by rotating a hammer using a protrusion on the cam plate and rolling the characters while pressing them against the printing paper, resulting in a quiet printer with almost no printing noise.

Furthermore, there is no return spring when the carriage returns,
The power consumption is low, an inexpensive free-run motor can be used as the motor, and a small and inexpensive printer can be obtained.

As is clear from the above description, according to the present invention, a cam plate is provided along the reciprocating path of the carriage, and a type belt for printing numbers and a type belt for printing symbols are provided in the vertical direction on the type drum. A hammer for printing numbers and symbols is provided with one end inside the type drum and the other end facing the cam plate side.
Since the cam plate side has a structure in which a plurality of protrusions for numbers and symbols are provided, at least two symbols can be printed, and it can satisfy many uses.

It is possible to provide a compact serial printer that can

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention. Figure 1 is a perspective view explaining the overall structure, Figure 2 is an explanatory diagram showing a part of the power transmission mechanism, and Figure 3 is an illustration explaining the structure of the drum. FIG. 4 is an explanatory diagram of the claw attached to the number printing hammer, FIG. 5 is an enlarged perspective view of the cam plate, FIG. 6 is a plan view showing the drive control mechanism of the carriage, and FIG. The figure is a side view of the cam plate, Figure 8 is a longitudinal side view showing the mounting structure of the ink roller, Figure 9 is an explanatory diagram showing the carrying operation by the rack plate, and Figures 10 (A) and (B) are the clutch. A vertical side view explaining the operation of the gear, FIG. 11 is an explanatory diagram showing the paper feeding mechanism,
Figures 12 (A) to (F) are explanatory views of the control lever operation showing the carriage carry-up operation, Figure 13 is a plan view showing the operation of the symbol printing hammer, and Figure 14 is the carriage return operation. 15(A) to (f=) are explanatory diagrams showing the engagement operation between the cam plate and the leaf spring, and FIG. 16 is a perspective view showing the engagement between the clutch gear and the PF lever. Figure 17 is a plan view showing the operation of the number printing hammer during digit return operation, Figure 18 is an explanatory diagram of the TR signal detection mechanism,
FIG. 18 is an explanatory diagram showing another example of the structure of the symbol printing hammer, FIG. 20 is an explanatory diagram showing another example of the TR signal detection mechanism,
FIG. 21 is a timing chart. 1... Frame 2... Motor 3... Solenoid 4... Tacho generator 6... Rotating shaft 9... Worm gear lO... Magnet 11... Drum gear 14... Carriage
15...TR drum 16...Drum base 1
7... Number type belt 18... Symbol type belt 19... Hammer for symbol printing 20... Hammer for number printing 21.23... Roller 22... Cam plate
25...Claw 26...Ink roller case 28
... Ink roller 30 ... Return spring 32.
...Drive gear 33...Control lever 34...
・Rack plate 34a... Rack teeth 36... Lever 37... Armature 39... Platen 41
...Clutch gear 43...Worm part 46...
・PF lever 47...PF gear 48...rubber roller 51...plate spring 51a, 51b,
. . . Free ends 52a to 52c . . . Conductive coatings 53a, 53b - Brush Fig. 2 Fig. 3 Fig. 4 Fig. 15. (A) (B) (C) (D) Figure 17

Claims (1)

[Claims] In a small serial printer equipped with a type drum that rotates around an axis perpendicular to the digit direction of printing paper and a carriage that conveys this type drum in the direction of the printing digits, the type drum has a type belt for numbers and a type belt for numbers. , a symbol type belt is provided in the vertical direction, and a printing hammer for number printing and symbol printing is rotatably provided on the carriage with one end facing inside the type drum and the other end facing outside the type drum, A cam plate is provided along the reciprocating path of the carriage, and a plurality of protrusions that engage with printing hammers for number printing and symbol printing are provided on the cam plate at the number and symbol printing positions, respectively. Small serial printer.