JPS6018369A - Printer - Google Patents

Abstract

PURPOSE:To make accurate a printing position and enhance reproducibility, by a method wherein at the time of manual operation, a stepping motor stopped is rotated for a predetermined period time to stably engage a detent mechaism, in a mechanism for stopping a paper at a predetermined position in feeding the paper. CONSTITUTION:A recording paper 2 is fed by a predetermined angle by rotating a platen 1 by the stepping motor 5. In the case of final positioning by manually operating a knob 15, the positioning is performed by the engagement of a detent gear 9 with a detent lever 10. In this case, an electric current is passed to the motor 5 to rotate the latter for a short period of time in accordance with the turning-ON and turning-OFF of a micro-switch 16 dependent on the position of the lever 10, whereby the lever 10 is stably engaged to the gear 9. By this operation, the printing position is made to be accurate, and the reproduciblity thereof is enhanced.

Description

TECHNICAL FIELD The present invention relates to a printing device, and more particularly to a printing device equipped with a detent mechanism.

BACKGROUND ART For example, in a printing device that wraps printing paper around a platen and prints on the printing paper, in the case of an electric type, a paper feed motor rotates the platen to feed the paper.
During printing, it is necessary to keep the platen in a static state.

In addition, in typewriters, which are a type of printing device,
When the printing device is in a standby state, it is necessary to manually adjust the printing paper to the printing position, and the platen must be provided with a detent mechanism.

This detent mechanism is a so-called anti-rotation mechanism, and is configured so that the platen can be rotated by clicking, and the click position and the printing position must accurately match.

A stepping motor is generally used to drive the platen, and the click sensation given to the detent mechanism is
There are two methods: one method is to apply an excitation current to the stepping motor when the platen is stationary, and the other method is to use the holding force of the motor, and the other method is to use a spring provided on the detent mechanism side.

A conventional example in which a click sensation is obtained by a spring provided on the detent mechanism side is shown in FIGS. 1 and 2.

In FIG. 1, the reference numeral 1 indicates a platen, and a recording paper 2 is wound around the platen 1. As shown in FIG. The recording paper 2 is pressed against the platen 1 by paper press rollers 3 and 4, and the paper press rollers 23 and 4 are respectively i;
It is rotatably supported on m13 and m14, and platen 1
It is constructed so that it can be suppressed and separated from the enemy.

On the other hand, the one indicated by reference numeral 5 is a stepping motor, and a belt 7 is stretched between a pulley 6 fixed to the output shaft of the stepping motor and a pulley 8 fixed to the platen 1 to transmit rotational force. There is.

Also, a detent gear 9 is provided coaxially with the pulley 8, and a detent bar 1 is provided below the detent gear 9.
0 is rotatably supported by a shaft 11.

A claw 10a is provided at one end of the detent lever 10, and the claw 10a and the detent gear 9 can mesh with each other.

Further, a spring 12 is stretched between the other end of the detent gear 9 and a fixed part of the device, and the detent lever 10
1, and the pawl a always provides a force for meshing with the detent gear 9.

In such a structure, normally the stepping motor 5
The stop phase position of the detent mechanism is adjusted to match the stable point of the detent mechanism, so when the platen 1 is driven by the stepping motor 5, even if the power to the stepping motor 5 is turned off after paper feeding The detent gear 9 constituting the detent mechanism and the pawl 10a of the detent lever 10 are set to be in a securely meshed state as shown in FIG. 2 (8).

However, in printing devices such as typewriters that can be driven manually, the user can feed the recording paper 2 by turning the platen knob 15, and the stepping motor 5 is not energized except when feeding the paper. Therefore, when manually feeding paper, it is necessary to position the paper using only the detent mechanism.

In this case, the rotational friction force of the platen 1, the tooth profile of the detent gear 9, the shape of the pawl 10a, the friction force between the pawl 10a and the detent gear 9, and the rotational friction force of the stepping motor 5 were included. All forces such as frictional forces on the drive transmission system become loads and are applied to the detent lever 10.

In such a state, the claw 10a should not be half-engaged with the detent gear 9 as shown in FIG. 2(B), but should be completely engaged as shown in FIG. The force of the spring 12 must be equal to the load mentioned above.

If this setting is not made, the claw 10a will stop in an unstable state as shown in FIG. 2 [Phase], and as a result, the printing position will become extremely vague.

However, when such a strong spring 12 is used, when the platen 1 is rotated by the stepping motor 5, a large load is placed on the stepping motor 5, and the relationship between the two only gets worse. , definitive solutions are becoming increasingly rare.

Purpose The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology.Even if the platen is manually rotated through the detent mechanism, the printing position can be maintained with high accuracy, and the printing position can be maintained with high accuracy. The purpose of this invention is to provide a printing device with extremely high repeatability.

EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

FIRST EMBODIMENT FIGS. 3 to 5 illustrate an embodiment of the present invention.
In the figure, the same parts as in Figures 1 and 2 are given the same reference numerals.
The explanation will be omitted.

In this embodiment, a microswitch 16 is arranged at a position corresponding to the detent lever 10, and the tip 16b of the actuator 162 is connected to the detent lever 10.
0 is placed in contact with the lower side of the claw 10a.

If the microswitch 16 is placed in this state,
When the platen 9 is rotated and the detent lever 10 is swung as shown in FIGS. 4(A) and 4(B), the microswitch 16 can detect this.

That is, when the claw 10a of the detent lever 10 is accurately engaged with the detent gear 9, the microswitch 1
The actuator 162 of No. 6 does not press the switch piece 16C of the microswitch 16, and the microswitch 16 is turned off. Then, as shown in FIG.
When a moves over the teeth of the detent gear 9, the actuator 162 is pushed, pressing the switch piece 16C and turning on the microswitch 16.

By providing the microswitch 16 in this way,
Rotation of the platen can be detected by turning on and off the microswitch 16.

Therefore, turn the micro switch 16 on and off to "1".

If it corresponds to the "0" state, the rotation of the platen can be detected as a logical electrical signal.

A block diagram of a control circuit using such electrical signals is shown in FIG.

That is, the reference numeral 17 in FIG. 5 is a CPU (central processing unit), and signals from the microswitch 16 and signals from the other detection means group 18 are input to this CPU 1γ.

Further, the stepping motor 5 and other non-grinding equipment group 20 are connected to the CPU 17 via drive circuits 19, respectively.

Based on such a circuit configuration, when the stepping motor 5 is in a stopped state, the microswitch 16 causes the above-mentioned [J,
When the signal "Fo" is input, the CPU 17
It is determined that the platen was operated manually.

And 11. J, roJ signal is “1” or “0”
'', that is, when the manual operation is complete. After the value is stabilized at either "1" or "O", the CPU 17 excites the stop phase of the stepping motor 5 for a certain period of time via the drive circuit 19 to correct the positional deviation of the detent mechanism.

By the way, in general, in typewriters and the like, the minimum feed amount of the stepping motor 5, which is the paper feed motor, and the minimum feed amount of the detent mechanism do not match.If the number of phases of the stepping motor is m, the minimum feed amount of the detent gear The unit is mn times the minimum feed unit of the stepping motor 5 (
n is an integer).

The reason for this is that since the platen is rotated manually, it is forced to stop at random positions, and the stable point of the tent mechanism must correspond to a certain phase of the stepping motor 5, otherwise it will lose synchronization. It is.

1) Therefore, by energizing the stop phase, which is the stop phase, the stepping motor 5 is rotated and the unstable state shown in Fig. 2 (G) returns to the stable state shown in Fig. 2 (A). let

Since the present embodiment is configured as described above, the detent mechanism can always be kept in a stable state without increasing the force of the spring that applies rotational force to the detent lever as in the conventional case.

Therefore, the load on the stepping motor 5 is reduced, and the click sensation is not impaired.

Of course, after the stop phase of the stepping motor is excited for a certain period of time, the stepping motor 5 is turned off and the platen is held only by the detent mechanism.

Second Embodiment In the above-described embodiment, the rotation of the platen was detected using a mechanical switch called a microswitch, but it can also be detected purely electrically.

Such a structure is shown in FIG. 6 and below.

The printing device to which this embodiment is applied is assumed to have a conventional configuration as shown in FIG.

FIG. 6 is a circuit diagram illustrating a second embodiment of the present invention. In the figure, reference numeral 35 indicates a coil section of the stepping motor 5, and the coil section 35 has four excitation networks.

The coil 35 is connected to the power supply vp through the transistor T0, and the stepping motor enable signal (M, IINBL) 36 is connected to the base of the transistor Tl.
is entered. Further, each of the four excitation terminals of the coil 35 is connected to transistors 37 to 40, respectively.

Further, transistors 23 and 24 are connected to one end and the other end of the coil 35, respectively.
, 24, a motor enable signal is input to the base side thereof.

Those indicated by symbols 26 and 27 are transistors 23 and 2.
4 and its output is one AND gate 28
has been entered.

Next, the operation of this embodiment configured as above will be explained.

First, the motor enable signal 36 becomes "0", and the transistor 3 changes according to the excitation timing of each phase of the coil 35.
When a signal is input to 7 to 40, at that excitation timing,
Stepping motor 5 rotates. At this time, since the motor enable signal is also input to the base sides of the transistors 23 and 24, the transistors 23 and 24 are turned off, and everything other than the drive circuit system is disconnected.

On the other hand, when the motor enable signal 36 is "1", that is, when the stepping motor is stopped, the transistors 23 and 24 are turned on.

In this state, -L-5a... operation is performed, and - when the chipping motor 5 is reversely rotated by an external force, a voltage is induced in the excitation phase 35a.

In this case, for example, if the transistor 23 connected has a higher potential in the excitation phase 35a, the current flows in the direction shown by the arrow 31 in FIG.
The potential of the output 33 becomes greater than zero.

Reference potential 2 determined by this potential 33 and resistances 29 and 30
5 is input to the comparator 26, and the potential of 33 is the reference potential 2.
5, the output signal of the comparator 26 becomes “1”.
” becomes rOJ. On the other hand, in the excitation phase 35a, contrary to what has been described above, when the side to which the transistor 24 is connected becomes a high potential, the potential of the output 34 of the transistor 24 becomes greater than 0, and the potential of the output 34 becomes higher than 0 in the comparator 27. It is compared with the reference potential 25, and if it is less than the reference potential 25, the output of the comparator 27 becomes "1" or IJOJ.

The outputs of the comparators 26 and 2γ are each input to an AND gate 28, and the output of the AND gate 28 is "1" when the stepping motor is stopped, and "1" when the stepping motor is being operated manually. 0”.

By the way, the output signals of each part are shown in FIG.

Figures 7 (a) to (2) show the output signals of each part when the stepping motor is stopped, and Figures 7 (g) to (2) show the output signals of each part when the stepping motor is stopped.
J) shows output signals at various parts when the stepping motor is rotated by an external force.

The suffixes attached to V in FIGS. 7(5) to (J) are the same as the reference numerals of each part in FIG.

As is clear from FIG. 7(J), the stepping motor 5
When is being rotated manually, the output of the AND gate 28 28 is not always "0", so after some "0" signals come in and it stabilizes at "1", It is determined that the platen has been rotated.

FIG. 8 shows a block diagram of the control circuit. The output of the AND gate 28 mentioned above is input to the CPU 17,
As described above, when it is determined that the output of the AND gate 28 has stabilized at "1", U is the case where the manual operation of the platen has been completed, and therefore the stepper motor 5 is switched to the stop phase via the drive circuit 19. Apply excitation current for a certain period of time,
Rotate the detent mechanism until it is fully stable.

Since this embodiment is configured as described above, manual operation of the platen is electrically detected, the stop phase of the stepping motor is excited, and the day tent mechanism is stabilized by rotating the stepping motor. The print position can be maintained accurately, and the repeatability of the print position can be improved. Furthermore, as in the above-described embodiment, a strong spring for rotating the detent lever is not required, so a printing device with a good click feeling can be obtained.

Effects As is clear from the above explanation, according to the present invention, the present invention includes a detection means for detecting that the platen has been manually operated, and when the manual operation is completed, the stop phase of the stepping motor, which is the paper feed motor, is activated. By adopting a configuration in which the detent mechanism is energized for a certain period of time, the detent mechanism can be reliably set in a stable state, the printing position can be maintained accurately, the repeatability of the printing position can be improved, and the It is possible to maintain the lick sensation.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating a conventional structure, and FIG. 2 (5). (c) is an explanatory diagram showing the operating state of the detent mechanism;
Figures 1 to 5 illustrate one embodiment of the present invention.1. FIG. 3 is a perspective view, FIG. This is to explain another embodiment of the invention, FIG. 6 is a control circuit diagram, and FIG. 7 is a control circuit diagram.
Figures (5) to (2) are output waveform diagrams showing the output signals of each part when the stepping motor is stopped, and Figures 7 (F) to (J
) is an output waveform diagram showing the output signals of each part when the stepping motor is rotated by an external force, and FIG. 8 is a block diagram of the control circuit. DESCRIPTION OF SYMBOLS 1...Platen, 2...Recording paper, 5...Stepping motor, 9...Detent gear, 10...
Detent lever, 12... Spring, 16...
・Micro switch, 26, 27... Comparator, 2
8...AndGate, patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1) In a printing device equipped with a stepping motor for rotating a platen (paper feeding) and a detent mechanism that stops and holds the platen at predetermined angles when the stepping motor is stopped, when the stepping motor is stopped, A detection means is provided to detect that the siding tent is rotated manually, and when the siding tent mechanism is manually rotated, the stop phase of the stepping motor is excited for a certain period of time, and the siding tent mechanism is kept in a stable state by rotating the stepping motor. A printing device characterized in that it is configured to be set in the printer. 2) The printing device according to claim 1, wherein the detection means is a mechanical switch that detects displacement of a detent lever constituting a detent mechanism. 3) The printing device according to claim 1, wherein the detection means is an electronic circuit that detects a voltage induced in the excitation phase of the stepping motor when the stepping motor is manually reversely rotated.