JPH03183576A - Micro printer - Google Patents

Abstract

PURPOSE:To prevent reverse rotation of a type drum by connecting a drive motor and the drum through a spring clutch, and always applying a rotary force of a predetermined direction to an output gear if the drum is stopped by a selection lever to idle the clutch. CONSTITUTION:A spring clutch 18 is arranged near a type drum, and has a drive gear 19 to which the power of a drive motor is transmitted. A selection lever 30 formed with an engaging pawl 29 at its end is arranged rotatably at a central part as a fulcrum between a ratchet 12 and a sheet feeding drive gear 26. If the pawl 29 is engaged with the ratchet 12 to stop a type drum 3, a load is applied to the clutch 18 to idle the gear 19, a rotary force of a predetermined direction is always applied to an output gear 21 to prevent reverse rotation of the drum 3 without providing a reverse preventing mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a microprinter, and specifically relates to a microprinter that performs printing using a type drum having a plurality of type characters formed on its outer periphery.

[Conventional technology]

FIG. 5 shows a conventional microprinter. Inside the printer body 1, there are many printed characters 2, 2, . . . on the outer peripheral surface.
A cylindrical type drum 3 with a protruding .
, a hammer (not shown) that is driven to protrude by energizing the tile (not shown) to protrude the type 2 is a hammer (not shown) that protrudes the type 2.
They are arranged so as to correspond to the rows in the circumferential direction.

Further, on the outer circumferential side of the type drum 3, an ink liner 4 for applying ink to the type characters 2 of the type drum 3 is rotatably disposed in contact with the type drum 3. A platen 5 is disposed at a position corresponding to the tip of the hammer. G on one end of the type drum 3, Karukon on the NI part where the type is not numbered, jj
IrJ
A paper feed gear 7 that meshes with the intermittent gear 6 is disposed on one side of the ring 5.

Then, with the moeki type dome 3 rotated once and the part where no type is installed corresponds to the platen 5, the paper feed plate 77 is rotated by the intermittent gear (5) to feed the paper (not shown). The feed []-ra transports the specified paper by 1 (j minutes).Furthermore, the type driver l
A 1-1-9 type drive 98 for rotationally driving the type drum 3 is connected to one end of the \3. , L1 reversal prevention] f-r button 9 is installed around the printer main body 11.: A reversal prevention lever 10 whose tip is engaged with the reversal prevention U radiator 9 is attached. This reversal prevention lever 10 moves the above-mentioned 6-shaped drum 3 in the direction of arrow A.
It is designed to rotate only in the h direction.

In the conventional printer, the drive motor 8 simultaneously rotates the type drum 3 based on a predetermined print bind-off, and moves the type corresponding to the print size to the 41 character position facing the platen 5.
hsaqru. Thereafter, by driving the hammer to protrude toward the platen 5, the tip of the hammer hits the type drum 3.
Printing is performed by pressing the desired type 2 onto the paper. By repeating this operation and increasing the fA size, printing can be performed continuously.

[Problem to be solved by the invention]

However, in the conventional microprinter (well, in order to prevent the occurrence of printing defects due to the reverse rotation of the type drum 3), a reversal prevention ratchet 9 formed on the drive [-Y8] is used.
Since the reversal prevention lever 10 is engaged with the reversal prevention lever 10 to prevent the type drum 3 from reversing, the number of parts increases, leading to an increase in manufacturing costs.
Moreover, there is a reverse visit stop Ujit 9 and a reverse IJ1. There is a problem in that the contact between the lever 11 and the lever 10 is awkward.

The present invention has been made in view of these points, and it is possible to reliably prevent the type drum from reversing, and moreover, it can be applied to women's prices, and it can reduce noise. The objective of the invention is to provide a microprinter capable of reducing the amount of 1.

[Means for solving the problem 4] 1 v 1 [1 part 4! : A microprinter according to the present invention (well, a type drum with type formed on the outer circumferential surface is rotatably provided by a driving tanabata, and the desired type is selected on the type type drum, and the type is printed on the type drum). A microprinter is equipped with a selection lever for performing assembly feeding movement corresponding to the portion of the printing drum where type is not formed, and the drive gear connected to the drive motor and the drive gear connected to the drive motor are connected to the drive gear. An output horn gear connected to the drive gear of the type drum is turned to the right, and a spring clamp is provided which is idled when a certain torque is applied to the output gear. The gear ratio with the driving gear is set to an integral multiple, and a cam groove corresponding to the portion of the type drum where type is not formed is formed in the prong gear of the spring clutch, and the paper feeding operation of the selection lever is formed. The present invention is characterized in that an It feed drive gear is provided which is selectively connected to the drive motor in correspondence with the cam groove of the output gear and which is driven in 11 rotations when selected.

[For production]

According to the present invention, when printing, the selection lever is operated based on the signal corresponding to the type to select the desired type, thereby stopping the type drum and printing the desired type on the paper.・At this time, zero is applied to the output gear of the spring clutch, causing the drive gear to idle, but since a rotational force in a constant direction is always applied to the output gear, the type drum does not rotate in reverse. This can prevent printing defects caused by reverse rotation of the type drum.
It is possible to reliably prevent this. When paper is to be fed, the selection lever is operated to put the paper into the paper feeding operation state, and the paper feeding drive 1a is set at the timing 1lIIt! according to the cam groove of the output gear. As a result, the rotational driving force of the upper drive unit is transmitted to the paper feed drive m1lli'a, and a predetermined paper feed is performed. At this time, since the gear ratio between the output gear of the spring clutch and the drive gear of the type drum is set to an integral multiple, paper feeding is performed after the type drum has rotated an integral number of times. Due to the cam groove of the output gear, the paper feed is (j) corresponding to 7C where no type is formed.

〔Example〕

Hereinafter, embodiments of Komei Ki will be explained with reference to FIGS. 1 to 5.

Figures 11i2I to 4 [4L*Microphone according to the invention “1
This figure shows an embodiment of the drive 1M11 portion of the printer. In order to print in two different colors on the outer peripheral surface of the cylindrical type drum 3, two sets of type characters 2, 2, . . . Each digit is divided into rows in the axial direction. Further, at one end of the type drum 3,
117K (corresponding to radial tooth 1 of each type 2) on the outer periphery
A ratchet 1-12 having a letter GJ formed thereon is attached coaxially to the outer periphery of the labette 12, corresponding to the two portions of the type drum 3 where the letters are not provided, and the ratchet rli11. Notches 13, which are deeper than the grooves between them, are formed approximately in pairs in the diametrical direction. The type drum 3 and the ratchet h1
2, a transmission gear 14, an intermittent gear 15 whose south end is formed only in the portion of the type drum 3 where no type is provided, a code plate rotating gear 16, and a groove for shifting the type drum 3 in the digit direction. A cam body 17 is arranged coaxially with the ship.

Further, a spring clutch 18 is disposed near the type drum 3. As shown in FIG. 3, this spring clutch 18 has a drive gear 19.A drive shaft 20 is integrally attached to this drive gear 19.
An engagement tube 22 of an output gear 21 having a gear ratio of 2:1 with respect to the transmission gear 14 is engaged with the outer peripheral side of the drive shaft 20. A locking groove 23 extending in the axial direction is formed in this engagement n22, and a coil spring 24 is attached to the hook on the outer circumference side of the drive shaft 20 and the inner circumference side of the engagement tube 22. Part 2
4a is attached so as to be engaged with the locking groove 23. Further, the rotational driving force of a drive gear (not shown) is transmitted to the drive gear 19, and the output 8
In %A21, there is a story 7 through the idle gear shown in the illustration.
A transmission gear 14 of the drum 3 is connected. Therefore, when a constant 1-lux is applied to the output gear 21, the spring 24 slips with respect to the drive shaft 20 and no longer transmits rotational force. It is determined by the following formula.

T = 2 E IΔD/D2 Here, [:A7 angular ratio l of the material of the coil spring 24: Moment of inertia of area Δl of the coil spring 24):] Tightness D of the coil spring 24: Diameter of the drive shaft 20 .

Further, on the outer periphery of the flat portion of the output gear 21 of the spring clutch 18, the notches of the ratchets I to 12 are fully formed.
A cam groove 25 corresponding to No. 3 is formed, and a paper feed drive gear 26 that is biased counterclockwise in the figure by an elastic member (not shown) is disposed near the output gear 21. . A control claw 27 whose tip is divided into two is formed protruding from the outer periphery of the paper feed drive gear 26, and an engagement protrusion 28 is formed on one surface of the paper feed drive gear 26.

Further, between the ratchet 12 and the paper feed drive gear 26, there is a selection lever 30 having an engaging pawl 29 at its tip.
is arranged on the rotary mortar I' with its central part as a fulcrum, and at the end of this selection lever 30 on the paper feed drive gear 26 side,
#J vA An engaging portion 31 that is engaged with the engaging protrusion 28 of the feed drive gear 26 is formed. The selection lever 30 is rotated by, for example, an electromagnetic clamp or the like so that the engaging pawl 29 can engage with the ratchet +-11Iii or the notch groove 13 of the lovette 12 #1II12, and the selection lever When the engagement pawl 29 of No. 30 engages with the love button south 11 of Ratchets 1 to 12, the selection (
1 Clever 30 engaging portion 31 and the paper feed drive gear 2G
If the engagement with the engagement protrusion 28 is not released, and the engagement claw 29 of the selection lever 30 is not fully engaged,
3, the engagement between the engagement portion 31 of the selection lever 30 and the engagement protrusion 28 is released.

Next, the n river of this embodiment will be explained.

First of all, for the first time
As shown in >, the paper feed drive 1a 26 is rotated because its engagement protrusion 28 is engaged with the engagement part 31 of the selection lever 30, and in this state, the drive morph causes the spring clamp to be released. The drive gears 19 of 18 are driven synchronously, and the active driver 113 is rotated synchronously through the output 1'a 21 of the 18 drive gears 19.
T! Ru.

And, as shown in the 10th ([)), this l' In
During the first turn of ff, the selection lever 30 is moved to 11 in FIG. +IJ II direction,
It is a good idea to engage the engaging pawl 29 of the selection lever 30 with the edge 11 of the ratchet 12! The drum 3 is stopped at a predetermined character position. This is j-su-
Since a load is applied to the output gear 21 of the spring clutch 18, the inner circumferential surface of the spring 2/l and the outer circumferential surface of the drive shaft 20 slip, causing the drive gear 19 to slip. The output gear 21 is rotated idly, and no rotational driving force is transmitted to the output gear 21. In this state, a printing mechanism such as a hammer (not shown) performs desired printing on the paper.

In this way, the selection lever 30 is appropriately oscillated as shown in FIG.
Half a digit is printed at 11'J, where the drum 3 rotates at the same time.

Then, when the type drum 3 rotates ``1'' - synchronously, as shown in Fig. 4 (
As shown in a), rotate the selection lever 30 so that the engaging pawl 29 of the selection lever 30 is fully aligned with the notch 13 of the ratchet 12.
By engaging with the engagement protrusion 28 of the paper feed drive gear 26 and the engagement portion 31 of the selection lever 30, the engagement of the engagement protrusion 28 of the paper feed drive gear 26 with the engagement portion 31 of the selection lever 30 is released. By 4 forces, 111 + 27 claws
One side of the spring clutch 18 contacts the outer circumferential surface of the output gear 21 of the spring clutch 18, and is oriented in the opposite +15 meter direction in the figure.

Thereafter, the selection lever 30G is returned to its original (on) position, as shown in FIG. is released, and as a result, the load on the force gear 21 is released, and it becomes possible to drive the output -1 gear 21&1 rotation.

Then, when the output gear 21 /f1 rotates four times,
As shown in Figure d (C), paper feed drive-1! A2
The one-horn υ11II pawl 27 of 6 is engaged with the cam 25 and rotated slightly in the counterclockwise direction n17j in the figure, and the output key 721 rotates once, as shown in Figure 4 (d).
), the other i, l of the paper feed drive gear 726
1tIll claw 27 is engaged with hm 25 and rotated at the same time,
Climb up to this, 8th floor! As shown in /10(C), the rotational driving force is transmitted to the paper feed drive gear 26, and the rotation is further transmitted to the group feed gear 7, so that the predetermined M feed h<11 is achieved.At this time, , since the gear ratio between the love I nut 12 and the output gear 21 of the spring clutch IE3 is set to 2=1, the output key 721 rotates twice, that is, the #5 type drum 3 rotates once. After that, the paper feed is h 1
．． Moreover, since the cam 25 of the output gear 21 corresponds to the notch 13 of the ratchet 12, the paper is fed at a position where no type is provided.

The gear ratio between the ratchet 12 and the output key 721 of the spring clutch 18 may be an integral multiple of each other. Paper feeding operations can be performed at various timings.

By repeating the above operations, a large number of lines can be printed.

Therefore, in this embodiment, when the engaging pawl 29 of the selection lever 30 is engaged with the ratchet 12 to stop the type drum 3, the spring clutch 1
When a load is applied to the drive gear 8, the drive gear 19 is idled.In this case, a rotational force in a certain direction is applied to the output gear 21, so a conventional reverse rotation prevention mechanism is not used. It is possible to prevent the type drum 3 from reversing without providing a This makes it possible to reliably prevent the occurrence of printing defects due to the reverse rotation of the type drum 3, and also to significantly reduce the noise of the reverse rotation prevention mechanism.

Also, paper feed drive%? If 'j' 26 is driven via the spring clutch 18, the structure can be formed precisely, but the spring clutch 18J3
Because high torque is required from the motor and the drive motor, too!
I! Although the manufacturing cost would be high, in this embodiment, the feed drive is carried out by the spring clutch 18.
Since the drive is performed without using the drive motor, the drive torque of the drive motor can be small, and the Y4B cost can be reduced.

J3, the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways according to necessity.

〔Effect of the invention〕

As described above, the microprinter according to the present invention (
The drive motor and the type drum are connected via a spring clutch, and when the selection lever is used to stop the type drum and the spring clutch is idled, a rotational force in a fixed direction is always applied to the output gear. Therefore, it is possible to prevent the type drum from reversing without providing a conventional reversal prevention mechanism, and it can be manufactured at low cost.

As a result, it is possible to reliably prevent the occurrence of printing defects due to reverse rotation of the type drum.Furthermore, since the reverse rotation of the type drum is not prevented by an engaging action, there is no possibility of contact when preventing reverse rotation. Qin the effect of customers can be reduced.

[Brief explanation of drawings]

1 to 4 show examples of the microprinter of the present invention, and FIG. 1(a) is a plan view of the spring clutch portion showing the first period state, and FIG. 1(b) is a plan view of the spring clutch portion. A plan view of the spring clutch portion showing the type selection state,
Fig. 2 is an exploded perspective view of the type drum part, Fig. 3 is an exploded perspective view of the spring clamp, Fig. 4 (a), (b),
(C). (d) and (e) are plan views of the spring clutch portion showing paper feeding operation states, respectively, and FIG. 5 is a perspective view showing a conventional micro printer. 3... Type drum, 11... Ratchet 1-tooth, 12
...radiet, 13...notch groove, 18...spring clutch, 19...drive gear, 21...output gear, 2/l...spring, 25...cam groove, 26・
・・Paper feed drive gear, 27・υ1tll claw, 28・
...Engagement protrusion, 29...Engagement claw, 30...Selection lever application fee! ! +! Person 1 Shunsuke Oo Figure 1 (a) Figure 1 Lll (b) Figure 4 (a) Figure 4C (b) Figure 4 Figure 5

Claims (1)

[Claims] A type drum having type characters formed on its outer circumferential surface is rotatably provided by a drive motor, a desired type is selected on the type drum, and a paper feeding operation is performed corresponding to a portion of the type drum where type is not formed. A microprinter is provided with a selection lever for controlling the printing type, and the microprinter includes a drive gear connected to the drive motor and an output gear connected to the drive gear of the type drum, and the printer is configured to idle when a certain torque is applied to the output gear. A spring clutch is provided, and the gear ratio between the output gear of the spring clutch and the driving gear of the type drum is set to an integral multiple, and the type of the type drum is formed on the output gear of the spring clutch. cam grooves are formed corresponding to the portions where the paper feed operation is not selected, and a paper feed drive gear is provided which is rotationally driven when the selection lever selects the paper feed operation and is selectively connected to the drive motor in correspondence with the cam groove of the output gear. A micro printer characterized by: