JPS585789B2 - small printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized printer that prints by selectively locking a type ring around which are printed characters, symbols, etc.

Printers are used as display devices for electronic desktop calculators, etc., but in this printer, the drive motor is kept stationary and on standby when not printing, and the drive motor is supplied with power when printing. After entering the selection process of the wheel, passing through the printing process of printing selected type characters, and returning to the alignment of the type wheel to a standby state, approximately one printing cycle is completed, and it is like waiting for the next printing again.

Calculator printers are increasingly required to have high printing speed, little variation, and low price, and this printer satisfies these requirements.

That is, in the selection process, the first print signal corresponding to the print character is selected.
This signal group and a second signal, which is a standby signal that determines the return of the type wheel to the standby state and the power cutoff position of the drive motor, are obtained from one detector, and the timing signals are integrated. , the number of detectors required in the past has been reduced by half since separate detectors were used.

Furthermore, when the type wheel returns to the standby state, the printed characters are fed and the operator of the calculator can see the printed characters, so it is assumed that the printing cycle has roughly ended. With this printer, one print cycle ends as soon as a standby signal is generated, and the next print cycle can begin immediately.Therefore, there is no need to set a waiting time between print cycles, which improves printing speed. In addition, variations in printing speed due to variations in setting time are completely eliminated.

Furthermore, since the detector for obtaining the timing signal is set at a location corresponding to the movement of the type wheel spindle, highly accurate type signals and standby signals can be obtained.

Furthermore, when printing cycles are continuous, it is possible to rotate the drive motor continuously, which reduces power consumption by avoiding starting current, and increases lifespan in the case of brush motors. It is something.

Furthermore, when the type wheel is released from frictional engagement with the type wheel axle and is selected and returns to the standby state after printing, the type wheel axle rotates in the opposite direction to return the type wheel, and the type wheel axle is rotated in the same direction. It is easy to adapt to any case, such as a method in which the type wheel is returned to its original position after a total of one rotation after successive rotations, or a method in which the type ring is returned to its original position in the same direction but in a second rotation.

Conventional printers either have two separate detectors to obtain print signals and a stop signal to determine the power cutoff position of the drive motor, or even if there is only one detector to obtain print signals. Ancillary mechanisms such as clutches were added.

An example of a conventional printer having two detectors will be explained with reference to a schematic structural diagram in FIG. 1 and a time chart in FIG. 2.

Reference numeral 1 denotes a printer driving motor, and a series of printing operations is started when the motor starts to be energized.

2 is a motor gear, 3 is a reduction gear that rotates approximately once per printing cycle, 4, 5, 6, and 11 are transmission gears, and 7 is provided with a tooth portion and a notch portion of the tooth bottom diameter in a part of the circumference. 8 is an intermittent gear with a part of the gear cut out; 9 is a type wheel disposed on the intermittent gear 8 and having type letters on its circumference from which arbitrary characters can be selected by a type wheel selection mechanism; 10 1 is a coil spring having one end fixed to the intermittent gear 8 and the other end fixed to the frame, and 12 is a printing gear having the same rotation ratio as the intermittent drive gear 7.

13 is a crankshaft engaged with the printing gear 12; 14 is a printing roller that is engaged with the crankshaft 13 and prints while rolling over the type on the type wheel 9; 15 is printing paper; and 16 is a ribbon.

The state shown in the figure shows the standby state.

According to the printing command shown in Fig. 2, the printer drive motor 1
is driven, the intermittent drive gear 7 starts rotating in the direction of the arrow 17, the teeth on the intermittent drive gear 7 and the teeth on the intermittent gear 8 start to mesh, and the intermittent gear 8 winds up the coil spring 10 in the direction of the arrow 18. while rotating.

When the intermittent gear 8 rotates, a detection plate (
(not shown) also begins to rotate.

Then, the slit of the detection plate receives a timing signal T shown in the time chart of FIG. 2 via a light emitting element and a light receiving element (not shown).

~T12 is generated, and a selection process is started in which characters can be selected by the type wheel selection mechanism.

Here, the initial position (standby position) of the detection plate corresponds to the part of the detection plate where no slit is provided to the light emitting/light receiving element, so the timing signal starts from Low and reaches the print position. A signal rises from Low to High every time the corresponding slit corresponds to a light emitting/light receiving element.

When the intermittent drive gear 7 continues to rotate and the character selection is completed, the intermittent drive gear 7 and the intermittent gear 8 are disengaged, and the intermittent gear 8 winds up the coil spring 10 due to the uncut portion 19 of the intermittent drive gear 7. At this time, when it was locked in a closed position,
The printing roller 14 rotates in synchronization with the intermittent drive gear 7, and when the selection of the type wheel 9 is completed and the intermittent gear 8 is locked, the printing roller 14 rolls over the selected type and prints it on the printing paper 15. This is the printing process for printing.

When printing is completed, the intermittent gear 8 is locked and the intermittent drive gear 7
The process ends due to the notch in the root diameter of the tooth, and is returned to the standby position by the coil spring 10.

At the same time, the type wheel 9 also returns to its standby position in a return process.

During this return stroke, the detection plate having the slit corresponding to the position of the printed characters is rapidly returned by the coil spring 10, so that an unstable return signal R having a short cycle and unrelated to the selection is generated.

Paper feeding is performed by a paper feeding mechanism after printing is completed.

Taking into consideration the mechanical load of the printer, motor inertia, etc., a detector is constructed from a magnet 20 installed on the reduction gear 3 and a reed switch 21 installed on the printer frame, etc., during paper feeding or before and after paper feeding. A stop command as shown in FIG. 2 is generated, and the printer drive motor 1 is de-energized by this stop command, electrically braked and abruptly stopped, and the intermittent drive gear 7 is stopped at a predetermined standby position.

When the printer drive motor 1 stops, paper feeding ends, and the intermittent gear 8 and type wheel 9 return to their standby positions, the printer waits for the next printing instruction.

Thus, one printing cycle is completed, and printing is performed by repeating this cycle.

The stop command has the following functions as shown in Figure 3.
A motor drive signal is created that starts with a print command and ends with a stop command.
time or β time from the leading edge of the stop command, the latter is used to measure the time since the stop command was generated using a β time counter with a clock sufficiently smaller than the β time as input, and one printing cycle is performed. Detects the end of.

d resets the character count and synchronizes the timing signal with the type on the type wheel 9, even if the printer is stopped at any position in the standby state (for example, when the printer is in operation) This enables synchronization (resulting from a power outage).

b is a motor control circuit, 42 is an ON-OFF control transistor, 43 and 44 are drive transistors connected by Darlington, 48 is a stop transistor that applies electrical braking to the motor 1, and 41 is an input terminal for a motor drive signal, which is set to low level. At this time, the motor 1 is driven by the conduction of the drive transistors 43 and 44, and the rotational speed of the printed characters is controlled at a constant speed by a mechanical governor or the like during the selection process.

When 41 is applied with a high level due to a stop command, 42
The ON-OFF control transistors 43 and 44 are turned on, and the supply of base current to the drive transistors 43 and 44 is stopped, cutting off the current to the motor 1, and at the same time, the stop transistor 4 is turned off.
8 is brought into conduction to short-circuit the terminals of the motor 1, causing it to suddenly stop.

Such a stop command requires parts such as reed switches and permanent magnets, which increases the price, increases the price due to assembly adjustments, requires installation space, which limits the printer shape and layout, and furthermore, because the reed switch is a mechanical contact, it increases the price. It has some drawbacks such as reduced reliability.

Furthermore, it also has the disadvantage that the printing speed per printing cycle is reduced.

In other words, when used in an electronic desktop calculator etc., β
Since the clock of the time counter is generated by an astable Maruna vibrator, there are variations due to variations in elements, temperature characteristics, etc.

Therefore, the number of stages of the β time counter is determined so that β time can be obtained even if the clock cycle is the minimum, so that a normal clock requires a waiting time longer than β time.

This results in the original printing speed of the printer being obtained, less than that in the normal case, and itself in the maximum case.

Further, FIG. 4 shows a time chart of an example in which a timing signal consisting of only a print signal and a clutch are used.

Power to the motor is started along with the print command, and after a run-up period of σ time, the clutch is engaged.

The operation of the clutch is started by energizing an electromagnet or the like.

With the clutch input, the printing wheel? rotation is obtained, and the print signal T.

-T1 occurs.

After the selection and printing process, the motor power is cut off after detecting the ρ time with reference to the final pulse of the return signal R, which occurs when the type wheel returns to alignment.

The clutch is mechanically released before power to the motor is cut off, and the type wheel is stationary again.

After α time has passed since the last pulse of return signal R,
One print cycle is completed.

The present invention eliminates the need for a conventional detector consisting of a reed switch and a permanent magnet, and allows the timing signal to also serve as a stop command.

Furthermore, the present invention is intended to improve the printing speed, eliminate its variation, and simplify the mechanism.The present invention will be explained below with reference to FIGS. 5 to 9.

First, the operation will be explained using the type selection mechanism shown in FIG. 5 and the time chart shown in FIG.

The rotation of the intermittent rotation drive gear 7 meshes with the intermittent gear 8, and rotates in the direction of arrow 18 A while winding up the coil spring 10.

When the intermittent gear 8 rotates, the type wheel 9 also rotates due to the spring 39 (Figure b) inserted into the type wheel 9, and the detection plate 35 of the type wheel position detector 32, which is locked to the shaft 31 of the intermittent gear 8, It also rotates.

A detection plate 35 (synchronizing member) attached to a shaft 31 that synchronizes with the movement of the type wheel 9 has slits 36 corresponding to each type position on the type wheel 9, and a slit 36 near the standby position where the type wheel 9 is stopped. It has a correspondingly wide slit 36-S that is unrelated to the position of the printed characters.

A light-emitting element 33 such as a light-emitting diode and a light-receiving element 34 such as a phototransistor are arranged facing each other with the detection plate 35 in between.

Further, a shielding plate 51 having an opening 52, a shielding part 53, and a cam part 54 is arranged between the light emitting element 33 and the light receiving element 34.

When the type ring 9 is in a standby state, the wide slit 36-S of the detection plate 35 and the opening 52 of the shielding plate 51 are aligned with the optical axes of the light emitting element 33 and the light receiving element 34, so the timing signal is High. in a state.

When the shaft 31 rotates, each slit 36 corresponding to the position of the type passes through the optical axis of the light emitting element 33 and the light receiving element 34, thereby generating a timing signal T(1'T12).

Further, this timing signal To to T12 becomes a high-state pulse as shown in FIG. 6 every time each slit 36 passes through the optical axis of the light emitting element 33 and the light receiving element 34.

Furthermore, a timing signal T.

-TI2 has a long valley width when the motor is started, and becomes a valley width with a stable period when the rotation of the motor gradually stabilizes.

This timing signal T. −? The period in which 1 occurs is a selection process for selecting the type on the type wheel 9.

Therefore, at this time, when a pulse for the desired type position of each type wheel 9 is generated, a trigger electromagnet (not shown) is energized to move the type wheel selection pawl 37 to the type wheel locking pawl 3.
8, the type wheel 9 can be selected.

When character selection on the type wheel 9 is completed, the intermittent drive gear 7 and the intermittent gear 8 are disengaged, and the intermittent gear 8 is locked with the coil spring 10 wound up due to the uncut portion 19 of the intermittent drive gear 7. has been done.

At this point, the detection plate 35 is stopped at a portion where the slit 36 is not provided, so the pulse is in a continuous low state.

Subsequently, the printing roller 14 rotates in synchronization with the intermittent drive gear 7, and when the selection of the type wheel 9 is completed and the intermittent gear 8 is locked, the printing roller 14 rolls over the selected type and presses it. Print.

When printing is completed, the intermittent gear 8 is locked and the intermittent drive gear 7
, and the coil spring 10 returns the intermittent gear 8, type ring 9, and detection plate 35 to the standby position in the direction of arrow 18 B.

When the intermittent gear 8, type wheel 9, and detection plate 35 rotate in the direction of arrow 18 B and enter the return stroke, the cam portion 54 of the shielding plate 51 is controlled, and the opening 52 is connected to the light emitting element 33 and the light receiving element 34. Off the optical axis, shielding part? 3 faces this optical axis.

Therefore, even if the slit 36 provided in the detection plate 35 passes through the optical axis of the light emitting element 33 and the light receiving element 34, the optical axis is blocked by the shielding part 53, so the return signal R shown by the dotted line is erased and the timing signal is After the occurrence of T1, the pulse remains in the Low state following the printing process.

Subsequently, the protrusion 57 provided on the shaft 31 collides with a stopper 58 fixed to the frame or the like.

At this time, the cam portion 54 of the shielding plate 51 is controlled again, the shielding portion 53 is removed from the optical axis of the light emitting element 33 and the light receiving element 34, the opening 52 is opposed to this optical axis, and the wide slit provided in the detection plate 35 is opened. 36-S is also facing.

In this state, the wide slit 36-S is connected to the light emitting element 33,
Since it coincides with the optical axis of the light-receiving element 34, a high-state reference signal S is generated.

This reference signal S is generated.

When this reference signal S is generated, the power to the motor is cut off, and one printing cycle is completed with the motor remaining in a stopped operation.

If the next printing cycle is continuous, the standard? When the signal S is generated, the next printing command is applied, and the motor continuously rotates.

In addition, if the next printing cycle is not consecutive, that is, 1
When the motor is de-energized for each printing cycle and starts the next printing cycle, the reference signal S is in the High state, so a printing command is applied to any position after this reference signal S, and the next printing cycle is started. can enter the print cycle.

Next, a first embodiment of the present invention will be described with reference to FIG. 7, and a second embodiment of the present invention will be described with reference to FIG. 8, using the time chart of FIG. 6.

FIG. 7a shows that the valley width from T1 of the timing signal to the reference signal S is larger than the valley width δ of the timing signal and that more than γ time has elapsed. The signal generated after the elapse of γ time is regarded as the reference signal S.

A counter is used that detects a time γ which is larger than the valley width δ of the timing signal but smaller than the valley width from the timing signal TI2 to the reference signal S.

The input of the γ time counter is the timing signal T.

- The clock is sufficiently smaller than the valley width of T1.

A timing signal T is connected to the reset terminal R of the γ time counter.
.

- Tl2 is added. Therefore, the γ time counter receives the timing signal T.

~It is reset every time the High part of T1 comes, and the Low
Counting starts every time the width of the w-shaped valley is reached.

So? When the valley width after the timing signal T1 continues for γ time or more, an output signal is generated from the output terminal CouL of the γ time counter.

In FIG. 6, the output terminal Cout of the γ time counter is γ
The time counter is reset by the last timing signal T1, and the output signal is generated when the valley width after the timing signal T1 has exceeded γ time.

FF, is reset by the print command, and the .gamma. time counter. Set by the output signal.

FF is also reset by a print command.

The state in which FF is set by the output signal of the γ time counter is transmitted to the J and K terminals of FF, and the signal generated next to the timing signal T12, that is, the reference signal S, is input to trigger the timing signal. is input to the FF5, the output terminal Q5 changes from High to Low.

The output terminal of the FF5 becomes High in response to a print command, and becomes Low in response to the reference signal S as described above.

Therefore, the output terminals are used to obtain energization signals for controlling energization of the motor and to detect the reference signal S.

By changing the output terminal Qs from High to Low, the next printing command can be applied at any time even when the reference signal S is no longer detected, and the next σ printing cycle can begin.

FIG. 7b shows φ in which the position of the type and the timing signal are synchronized by the output Cout of the γ time counter.

When the printer stops at an arbitrary position, the γ time counter generates an output signal when the C valley width continues for r hours or more after the timing signal T12, so FFfs set by the print command is reset.

Timing signal at AND gate? Only o-T1 is allowed and serves as an input to the character counter.

The character counter is reset by the print command, timing signal T.

-TI2 is input and counted.

The character counter is reset by a print command generated based on a reference signal S'k, and a timing signal T corresponding to the position of the printed character.

-T, so the contents of the character counter and the print position match.

Next, a second embodiment (FIG. 8) will be described with reference to FIG. 6.

FIG. 8 shows a predetermined number of timing signals T.

After confirming that T12 has occurred, the γ' time counter is activated to generate the timing signal T.

This is an example of determining between ~T1 and the reference signal S.

In other words, the seventh? To reduce the time of the counter from γ to γ', a character counter is used to time the timing signal T.

This is an example of determining between -T1 and the reference signal S.

That is, in order to reduce the time of the counter in FIG. 7 from γ to γ', the character counter is used in conjunction with the timing signal T.

-TI2 is generated a predetermined number of times, and then the width of the valley is counted and the reference signal S is looked at.

The character counter is reset by the print command and timing signal T.

- Count T1. The AND gate finds that the 13th T1 pulse of the timing signal has been generated from the 4-bit output signal of the character counter, and sets FF7.

γ′ time cow? Since FF7 has been reset to the print command, the clock input to the printer is not allowed by the AND gate until the 13th timing signal T1 is generated.

Is the γ′ time counter reset by a print command? Then, the γ' time is counted using the clock that is allowed after the timing signal T1.

Hereinafter, FF4 and FF5 have the same function as shown in FIG. 7a.

Although the timing signal has been described as changing from a high state to a low state, this can be easily changed from a low state to a high state by passing the reset input of the counter through an inverter. It is not limited to this.

In FIG. 9, the recess in which the type ring spring 39 engages with the shaft 31 is removed, and the rotational force of the shaft 31 is transmitted to the type ring 9 through friction with the type ring spring 39.

In this case, it is necessary to rotate the type wheel shaft 31 twice in one printing cycle, and each of the selection stroke and return stroke consists of approximately one revolution.

The type ring spring 39 is made inexpensive by a plate spring, and the coil spring 10 is removed to eliminate the energy loss of winding up the coil spring.

Since the type wheel shaft 31 rotates twice, the shielding plate 51 is required to eliminate the return signal.

As described in detail above, the present invention can achieve a small printer that requires high printing speed, low cost, etc.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of a conventional printer, where 1 is a drive motor, 9 is a type wheel, 20'' is a permanent magnet, and 21 is a reed switch. Fig. 2 is a time chart of a conventional printer. Fig. 3 is a circuit diagram thereof, in which a shows a motor drive signal, b shows a motor control circuit, C shows a circuit for detecting one printing cycle, and d shows an example of a circuit for synchronizing the type and timing signal. This is an embodiment of a printer having a clutch. Fig. 5 shows an embodiment of the printer according to the present invention, in which 32 is a type position detector, 35 is a detection plate, and 36-S is a reference signal slit. FIG. 6 is a time chart diagram of the printer according to the present invention;
FIG. 7 is a circuit diagram, in which a shows an example of a circuit for detecting the end of a printing cycle and a position where the motor's power is cut off, and b shows an example of a circuit for synchronizing printed characters and a timing signal. Figure 8 shows how to confirm that the timing signal has been generated and
'This is an embodiment in which a time counter is operated to distinguish between the first signal group and the second signal group. FIG. 9 shows an embodiment in which the type wheel is rotated twice in one direction.

Claims (1)

[Scope of Claims] 1. A type selection process in which the type wheel spindle, which supports the type wheel and rotates, makes one rotation each in the forward and reverse directions, or two rotations in the same direction;
In a printer that performs a printing process and a return process of aligning and returning the type wheel to a standby position, a slit is attached to the type wheel shaft and corresponds to the position of the type, and a slit is attached to the type wheel shaft and corresponds to the position of the type and corresponds to the standby position and is located at a motor power stop position. a detection plate having a corresponding wide slit, and a timing signal that is sent through the slit corresponding to the position of the printed characters to have a long valley width when the motor is started, and a valley width with a stable period when the rotation of the motor reaches steady rotation. T. -TI2 and? A light-emitting/light-receiving element that emits a reference signal S that is generated during the return stroke and stops the motor through a wide slit; a shielding plate that blocks a signal generated through a slit corresponding to the timing signal; a shielding plate that constantly detects the valley width of the timing signal, and detects a time period in which the valley width γ after the timing signal T1 is longer than the first valley width δ of the timing signal; A small printer, comprising: a counter that issues a signal when the timing signal elapses to distinguish between the timing signal and the reference signal. 2. Is it normal or reverse for the rotating type wheel shaft that supports the type wheel? Type selection process with one rotation each or two rotations in the same direction,
In a printer that performs a printing process and a return process for aligning and returning the type wheel to a standby position, a slit is attached to the type wheel shaft and corresponds to the position of the type, and a position corresponding to the standby position and a motor power stop position is provided. A detection plate having a wide slit corresponding to the position of the printed characters is detected through the slit corresponding to the position of the printed characters.When the motor is started, the valley width is long and when the rotation of the motor reaches steady rotation, the valley width becomes stable in period. Signal T. - a light-emitting/light-receiving element that emits T2 and a reference signal S that is generated during the return stroke and stops the motor through the wide slit; an optical axis of the light-emitting/light-receiving element is closed during the return stroke, and the printed character is a shielding plate that blocks signals generated through slits corresponding to positions of a predetermined number of the timing signals T; - detects the occurrence of T12, and issues a signal when the valley width γ' immediately after the last timing signal TI2 is longer than the valley width δ' in the timing signal; A small printer with a counter that distinguishes it from the other.