JPS5839074B2 - small printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a selection process of selecting a type wheel having printed characters such as letters and symbols around it, a printing process of printing the selected type, and a return process of returning the type wheels to a standby state. Regarding small printers that undergo

An object of the present invention is to make it possible to detect the position of a type on a type wheel using a single detector.

Another object of the present invention is that one detector is used both as a type signal corresponding to the type on the type wheel and a signal for detecting the end of one printing cycle.

Still another object of the present invention is that one detector serves both as a print signal and a signal for detecting the position at which power to the printer drive motor is cut off.

Still another object of the present invention is to obtain an easy control circuit for a printer and to eliminate any variation in printing speed depending on the circuit.

Still another object of the present invention is to provide a compact and inexpensive printer by integrating the printer's detector into one.

A conventional small printer will be explained with reference to a schematic structural diagram in FIG. 1 and a meme chart diagram in FIG. 2.

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

2 is a motor gear, 3 is a reduction gear that rotates approximately once per printing cycle, 4.5.6.11 is a transmission gear, and T is provided with a tooth portion and a notch portion of the tooth bottom diameter on a part of the circumference. 8 is an intermittent gear with a part of the gear cut out, and 9 is a type wheel having type letters on one circumference, which is arranged on the intermittent gear and selects any character by a type wheel selection mechanism. , 10 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; 14 is a printing roller that is engaged with the crankshaft 13 and prints while rolling over the type on the type wheel; 15 is printing paper; and 16 is a ribbon.

The state shown in the figure shows the standby state.

The printer drive motor 1 is driven by the print command shown in FIG. The gear 8 rotates in the direction of an arrow 18 while winding up the coil spring 10.

When the intermittent gear 8 rotates, the type wheel 9 also begins to rotate and a timing signal (To - T1□) is generated, leading to a selection process in which characters are selected by the type wheel selection mechanism.

When the intermittent drive gear 7 continues to rotate and character selection is completed, the intermittent drive gear 7 and the intermittent gear 8 are disengaged, and the intermittent drive gear 8 winds up the coil spring 10 due to the uncut portion 19 of the intermittent drive gear 7. It is locked in a closed position.

At this time, the printing roller 14 is rotating 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 the printing paper 15 is rotated. The printing process involves printing on the

When the printing is completed, the locking of the intermittent gear 80 is completed due to the notch in the bottom diameter of the intermittent drive gear 7, and the coil spring 10 returns the gear to the standby position.

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

At this time, the timing signal is unrelated to the selection, and a return signal R whose cycle is unstable is generated.

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

A magnet 2 is installed on the reduction gear 3 during paper feeding or before and after paper feeding, taking into account the printer's mechanical load and motor inertia.
0 and reed switch 2 installed on the printer frame, etc.
Configure the detector from 1, create the stop command shown in Figure 2,
In response to this stop command, the printer drive motor 1 is de-energized, the electric brake is turned off, and it suddenly stops, stopping the intermittent drive gear 7 at a predetermined standby position.

When the printer drive motor 1 stops, paper feeding is completed, and the intermittent gear 8 and type wheel 9 return to their standby positions, the next printing command is issued.

This completes one printing cycle, and printing is performed by repeating this process.

As shown in FIG. 3, the stop command has the following functions.

A creates a motor drive signal that starts with a print command and ends with a stop command, and in C, the end of one printing cycle is α time from the trailing edge of the dense timing signal R that occurs when the type wheel 9 returns, or the stop command Since it is β time from the leading edge of , the latter is used to measure the time after the stop command is issued using a β time counter using a clock that is sufficiently smaller than β time as input, and detects the end of one printing cycle. .

In d, the character count is reset and the timing signal is synchronized with the type on the type wheel 9, even if the printer is stopped at any position in the standby state (for example, if a power outage occurs while the printer is operating). synchronization (resulting from the occurrence of an event).

b is a motor control circuit, 42 is an ON-OFF control transistor p, 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 the motor 4 movement signal. When the level is low, 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 0N-OFF control transistor conducts, and the drive transistors 43 and 44 stop supplying base current and are cut off, cutting off current to the motor 1, and at the same time, the stop transistor 4
8 is brought into conduction to short-circuit the terminals of the motor 1, causing it to suddenly stop.

Such a stop signal requires parts such as reed switches and permanent magnets, which increases the price.1 The price increases due to assembly adjustment.Since installation requires space, there are constraints on the printer shape and layout, and furthermore, the reed switch is a mechanical contact. It had 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 multi-pipe brake, 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 the β time can be obtained even if the clock cycle is the minimum, so a normal clock requires a waiting time longer than the β time.

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

The present invention eliminates these drawbacks and allows the timing signal from the type position detector to play the above-mentioned basic role.

FIG. 4 shows a type selection mechanism of a small printer according to the present invention, and the same mechanical parts as in FIG. 1 are given the same numbers as in FIG. 1.

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

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

A detection plate 35 (synchronizing member) attached to a shaft 31 synchronized with the movement of the type wheel 9 has a slit 3 corresponding to the position of the type.
6, and a wide slit 36-8 which is installed near the standby state and is unrelated to the position of the printed characters.

The slit 36 of the detection plate 35 detects the character position on the type wheel 9 using a light emitting element 33 such as a light emitting diode and a light receiving element 34 such as a phototransistor, and activates a type wheel selection claw 37 by energizing a trigger electromagnet corresponding to the character position. is engaged with the type wheel locking pawl 38 to select the type ring 9.

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. ing.

At this time, the printing roller 14 is rotating 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 214 rolls over the selected type to perform pressure printing. .

When printing is completed, the intermittent gear 80 lock is turned off to the intermittent drive gear 7.
The coil spring 10 moves the intermittent gear 8 in the β direction of the arrow 18. Type wheel9. The detection plate 35 is returned to the standby position.

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

The present invention eliminates the need for a detector consisting of a reed switch and a permanent magnet, and uses a timing signal that also serves as a stop command. and detection of the end of one print cycle, b shows one embodiment of synchronizing the type on the type wheel with the timing signal.

The timing signal is a print signal T generated by the slit 36 corresponding to the print character.

-T1□, and a standby signal (reference signal) S corresponding to 36-8 (Srin) generated during the return process (after the selection process).

In this embodiment, in which the type wheel 9 reciprocates, the IJJ-ON signal R generated during the return process is erased by the shielding portion 53 of the shielding plate 51 used in the type position detector 32.

The opening 52 is in a standby state, and in the selection process the optical axes of the light emitting element 33 and the light receiving element 34 are aligned to receive the print signal T.

~ T12 is generated, and while the return signal R is being generated, the optical axis is deviated from the optical axis, and when the type ring 9 returns to alignment, when the slit 36-8 corresponding to the reference signal S arrives, the optical axis is aligned again at the cam portion 54. The controlled operation shown by the arrow 55 is obtained to generate the reference signal S.

If the stopping rotation speed of the motor is high, the motor may pass through the slit 36-8 and stop in the standby state.

FIG. 6a shows that the valley width from T12 to S of the timing signal is larger than the normal valley width 6, and the 7-hour counter detects that the valley width of the timing signal has exceeded γ time,
When the reference signal S is generated, the drive motor is de-energized,
The electric brake is lost and the vehicle comes to a sudden stop.

One printing cycle is completed with the motor remaining stopped.

When the next printing cycle is continuous, as shown by the two-dot chain line, the next printing command is applied at the same time as the reference signal S is generated, and the motor also rotates continuously.

b is used to obtain the cycle of printed characters and printed signal from the output Cout of the 1-hour counter. Even if the printer is stopped at any position, the reference signal S can be detected by rotating the motor when the power of a calculator, etc. is turned on. , b, synchronization is obtained and normal printing operation is performed.

Since the end of the printing cycle is detected without loss time due to control circuits such as clock variations, there is an advantage that the printing speed of the printer is not impaired.

Furthermore, in the case of continuous printing, the printing speed is expected to be further improved because the motor start-up time is reduced.

FIG. 7 shows an example in which the type wheel 9 rotates only once in one direction in one printing cycle, and the shielding plate 51 of the type position detector 32, which was necessary during reciprocating rotation, has been removed.

Reference numeral 61 denotes a fixing plate for the spring 63, which rotates in accordance with the rotation of the shaft 31.

Reference numeral 62 denotes a hook portion of the 9-needle 63 provided on the type wheel 9.

As the shaft 31 rotates, the spring 63 also rotates the type wheel 9.

In the selection step, a print signal T is generated in response to the slit 36.

NTt 2 occurs.

When a type is selected and the type wheel 9 stops, only the spring 63 is wound up by the shaft 31, and when printing is completed and the type wheel 9 is unlocked, the spring 63 starts rotating again, and the machine is in a standby state. This is the recovery process we are heading towards.

Near the standby state, only the reference signal S is generated by the slit 36-8, which does not correspond to printed characters and is wider than the slit 36.

That is, the detection plate 35 is roughly composed of a part having a slit 36 corresponding to the selection process, and a part having a slit 36-8 which is a shielding part at the beginning of the return process after the printing process and is near the standby state. .

As described in detail above, the present invention is small in size and low in cost.

It is fully suitable for small printers that are increasingly required to have reliability and high printing speed.

Further, the present invention is not limited by the detection method of the type position detector.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a conventional printer, in which reference numeral 1 indicates a drive motor, 9 a type wheel, 20 a permanent magnet, and 21 a reed switch. Figure 2 C is a main chart diagram of a conventional printer. Figure 3 is a circuit diagram, where a is a motor drive signal, b is a motor control circuit, C is a circuit that detects one print cycle, and d is a type and timing signal. An example of a circuit for obtaining synchronization is shown below. 4 at b shows an embodiment of the printer according to the present invention, in which numeral 32 represents a character position detector, numeral 35 represents a detection plate, and numeral 36-8 represents a reference signal slit. FIG. 5 is a mayme chart diagram of a printer according to the present invention;
FIG. 6 is a circuit diagram, in which a shows a circuit for detecting the end of one print 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 timing signals. FIG. 7 shows an embodiment in which the type wheel is rotated in one direction.
1 is a fixed plate, and 63 is a spring.

Claims (1)

[Claims] 1. A selection step in which a type wheel around which printed characters, symbols, etc. are arranged is rotated by the drive of a DC motor, and a desired character, symbol, etc. on the type wheel is selected; the selected character;
One printing cycle consists of a printing process in which symbols etc. are printed, and a return process in which the type wheel returns to a standby state after the printing process. an intermittent gear whose teeth are notched corresponding to the printing step and the return step; and an intermittent gear whose teeth are notched corresponding to the printing step and the return step; A portion where the teeth for rotating the rotating intermittent gear are cut, a portion where the teeth are not cut for locking the intermittent gear corresponding to the printing process, and a free return of the intermittent gear corresponding to the returning process. an intermittent drive gear that is divided into three parts by a notch in the bottom diameter and rotates once per printing cycle; a shaft that is coupled to the intermittent gear and holds the type wheel; a character on the type wheel that is attached to the shaft; A type position detector consisting of a detection plate, a light emitting element, and a light receiving element, which have a slit corresponding to the typed characters such as a symbol, and a slit wider than the slit provided at the end position of the return process at a position where there is no printed character. , a shielding plate that is located near the detection plate of the type position detector and does not block light to the light receiving element in the selection step and blocks light corresponding to the type in the return step; 1. A small-sized printer, characterized in that it uses a pulse from a position detector as a reset input, and obtains an output pulse after a predetermined time period longer than the width of the pulse corresponding to the character position has elapsed.