JPS60104365A - Type serial printer - Google Patents

Abstract

PURPOSE:To make it possible to miniaturize the titled printer and to reduce the cost thereof, by arranging the type wheel shaft on a carriage in a horizontal state and providing a shift cam mechanism and a shift clutch on the same axis as said type wheel shaft while also using a shift position detector as a type position detector. CONSTITUTION:When a shift trigger electromagnet 5 is excited after a type wheel shaft 12 begins to rotate, movable piece is attracted and a shift clutch disc 6-4 is rotated to a gamma-direction over a predetermined amount while a shift ratchet 6-2 is engaged with a ratchet wheel b-1 and a shift cam 7 is integrally rotated along with a type wheel group 10. The cam 7 has four stable points and the shaft 12 rotates by 1/4 during a time when a cam stroke, that is, the change position of the tupe wheel group 10 moves between adjacent stable points while the signal of a type position detector 17 is subjected to pulse detection and the electromagnet 5 is excited at every pulse. By this mechanism, miniaturization is enabled and the enhancement of assembling property and the reduction in the number of parts are attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a type serial printer, and particularly to a type serial printer that can perform alphanumeric printing.

<Prior Art> Conventional type serial printers of this type generally select characters by vertically shifting and rotating the type cylinder. In this case, the height and movement hk of the type cylinder are large, resulting in a large carriage, and the shift selection mechanism and character selection mechanism use a complex mechanism that combines multiple electromagnets, clutches, cams, and levers. Since the control method was also complicated, it was difficult to realize a small and inexpensive type serial printer.

In addition, in the serial printer proposed in JP-A-57-109677, although the above-mentioned drawbacks have been improved, in the shift means for shifting the group of type wheels, as shown in FIG. The drive force for shift selection is transmitted to the shift cam 7 in the carriage by the shift cam shaft 40, and a detector 46 is required to detect the shift position of the type wheel group. It could not be called a mechanism.

In addition, in a serial printer proposed in Japanese Patent Application Laid-Open No. 57-175188, a hammer and a type wheel group facing each other while holding printing paper are driven by independent step motors, and a shift is selected based on the difference in the transfer speed in each digit direction. However, because it requires an expensive mechanical part called a step motor and a transmission mechanism using wires for the shift selection, there was a drawback in terms of price. Furthermore, the control method for driving two independent step motors is complicated, and the step motor itself is generally not an efficient power source, making it difficult to reduce current consumption, especially when battery-powered. was there.

The present invention has been devised in view of these drawbacks, and it is an object of the present invention to provide a compact, low-cost type serial printer capable of alphanumeric printing.

Another object of the present invention is to reduce the current consumption of the printer mechanism and to provide a portable type serial printer powered by batteries.

<Features of the Invention> The features of the present invention for achieving each of the above objects are as follows.

First of all, in order to achieve the first objective of downsizing and lowering the price,
The type wheel shaft is arranged horizontally on the carriage, and the shift cam mechanism and shift clutch are arranged coaxially therewith, thereby achieving miniaturization (9) and improving ease of assembly. Furthermore, by using the shift position detector as a type position detector, the price can be reduced.

Next, in order to achieve the second objective of reducing current consumption, the driving force for shift selection of the type wheel group is obtained from the rotational force of the type wheel shaft using a small Do motor as the drive source.

<Embodiment> FIG. 1 shows the shift selection mechanism and its surroundings in an embodiment of the present invention, in which the carriage 18 is oriented in the digit direction β with respect to the printer body.
It is slidably held in the β on the carriage 18
A type wheel shaft 12 is arranged in the direction and is held so as to be rotatable and not to move relative to the carriage 18 in the axial direction. Since the type wheel group 10 is spline connected to the type wheel shaft 12 and biased by the shift return spring 11, its boss portion 35 comes into contact with the shift cam 7 via the shift cam passive body 8. Note that the shift return spring 11 is a removable stopper 37 attached to one end of the type wheel shaft 12.
The extraction is stopped by. The shift cam 7 is held by the carriage side plate 38 so as to be rotatable but not movable in the direction of the type wheel shaft 12, and further supports the type wheel shaft 12 at its center of rotation. The rotation of the shift cam passive body 8 is restricted by a shift guide shaft 36 whose one end is fixed to the carriage 18 . Incidentally, the cam slope portion of the shift cam 7 that contacts the passive body 8 has a viewing angle with a stable point corresponding to the number of stages of the type ring group (four stages in FIG. 1). , 6-1 to 6-10 in Figure 1 are the second
These are the components of the shift clutch 6 in the figure. The shift pawl wheel 6-1 is splined to the type wheel shaft 12 and fixed by crimping or a retaining ring. A shift claw shaft 6-5 is fixed to the shift cam 7 on the opposite side of the cam surface across the carriage side plate 3, and the shift claw 6-2 is rotatable around this shaft. There is a pin 6-6 at the tip of the shift claw 6-2.
is fixed and engaged with the elongated portion 6-7 of the clutch disc 6-4. The amount of rotation of the shift pawl 6-2 is determined by the shape of the long portion 6-7 and the rotation i & of the clutch disc 6-4. Another long hole on top 6-8 Crab
Since it is engaged with the shift pawl shaft 6-5, it receives a hit. Here, according to the shape number of the long portion 6-8, when the clutch disc 6-4 rotates in the γ direction and hits the
The pawl 6-2 is set to engage with the shift pawl wheel 6-1. In the normal state (the state shown in FIG. 1), the clutch disc 6-4 is biased by the shift pawl spring 6-3, so the notch 6-11 provided on the outer periphery of the disc 6-4 is locked by the movable piece of the shift trigger electromagnet 5, and the shift claw 6-2 is disengaged from the shift claw cap 6-1. In addition, this notch 56-11
The number corresponds to the number of stages of the type wheel. The detent spring 6-9 has its tip depressed into the notch (6-10) when the clutch is not operating (in the state shown in FIG. This is a spring for stabilizing the position.The shift reset detector 9 is a switch that detects the reference phase of the shift cam, that is, the shift reference position of the type wheel group.

Coaxially with the type wheel shaft 12, in addition to the above-mentioned mechanisms, a part of a character selection mechanism in the rotating direction of the type wheel and a type position detector are arranged. Selection gear 3-2 and selection pawl 4
-2 rotates integrally with the type wheel shaft 12, and the selection drive gear 5-
1. The same number of pawls as the number of positions of the type wheel are formed on the outer periphery of the selection pawl 4-2.
1 rotates in the ε direction, the selection pawl 4-2 is locked to select a character. Type position detector 17-1.17
-2 is a means for detecting the amount of rotation of the type wheel shaft 12 to obtain a type position signal and a type position reference signal, and the detection plate 17-1 rotates together with the type wheel shaft 12.

Next, the operation of the above mechanism will be explained. Since the drive source for shift selection is the rotational force of the type wheel shaft 12, the shift selection must be completed before the character selection process is completed. Third
This will be explained using a specific example according to the UXJ time chart. In addition, in this embodiment, the type wheel group is composed of four stages, and the type wheel 1
It actually consists of 24 characters, or 96 characters in total. Also, the shift cam has a standard stroke of 8 during one rotation.
1→S2→8. It is assumed that the cam curve has a displacement of →81. When the shift trigger is energized after the type wheel shaft starts rotating, the shift trigger electromagnet 5 in Fig. 1 is activated.
The movable piece of the shift clutch disc 6-
4 rotates a predetermined amount in the r direction, the shift pawl 6-2 comes into engagement with the shift pawl 6-1, and the shift cam 7 begins to rotate integrally with the type wheel shaft. The cam curve of shift cam 7 has
There are four stable points of 81 m 82 w"am" 4 mentioned above, and the type wheel axis rotates 1/4 while the cam stroke, that is, the amount of displacement of the type wheel group changes between adjacent stable points. Therefore, during this time, the print position detection signal is also /4X24=
Only +5 pulses are detected. Type ring group in j stages (j≦3)
In the case of shifting, a position detection signal of 6Xj pulses is detected, and the trigger electromagnet is energized every time 6 pulses of the print position detection signal are generated.

Since character selection cannot be performed while the shift clutch is activated, character selection is prohibited for 6×j pulses after the shift clutch is activated. Figure 6 shows the process starting from the position TP in the type wheel corresponding to 8% and ending with selecting the type corresponding to TPl in the type wheel corresponding to ``8''. If you want to select the typeface corresponding to 8. TP, ., typeface #1I
14I112 may be rotated one more time to select TP, .

Figure 2 shows an example of the application of a type serial printer according to the present invention. In the figure, the driving force of the motor 1 placed on the carriage is transmitted through deceleration means A2 and deceleration means B3.
These signals are input to a character selection clutch 13 and a print clutch 14, respectively. A selection printing trigger electromagnetic force i4 acts on these two clutch means, and when the trigger electromagnetic force 4 becomes energized, the type @@12 stops rotating and character selection is performed.
Next, one cycle of the printing process is performed after moving to the energization cutoff state. The type wheel set 12 continues to rotate until the selective printing trigger is energized for the first time, during which time the shift trigger electromagnet 5 is energized according to the procedure described above, and the shift clutch 6 is activated to move the type wheel group. A shift takes place.

In the embodiment shown in FIG. 2, the g power of the shift cam 7 is taken out by the paper feed drive gear 30. After the printer has printed one line, when the step motor 21 reverses and the carriage returns to the standby position, the paper feed drive gear 60 and the paper feed transmission gear 61 engage with each other.
The rotational force of the shift cam drives the paper feed shaft 34 via the gear train 50, 51, 32, 33. Therefore, by rotating the shift cam by a predetermined amount while the carriage is in a standby state, the printer can feed paper at various line spacings or rapidly feed paper.

<Effects of the Invention> As explained above, according to the present invention, the type wheel group shift selection mechanism is constituted by a pawl clutch mechanism, a trigger electromagnet, and a cam mechanism, so that no expensive parts are required and the shift position can be easily adjusted. The detector also functions as a type position detector, except for reference position detection, and most of the shift selection mechanism is placed coaxially with the horizontal type wheel shaft, making it suitable for downsizing printers and improving assembly. It has the advantage of being able to lower costs by reducing the number of parts. In addition, the drive source for shift selection is a small Dome that is common to the drive source for character selection and printing.
Since a motor is used, current consumption can be reduced. Therefore, it is small, low-cost, and battery-powered and portable.
It is most suitable as a type printer for alphanumeric printing.

[Brief explanation of the drawing]

Figures 1 to 3 all explain one embodiment of the present invention, and Figure 1 mainly shows the shift selection mechanism section in perspective view, and the second section is a block diagram of the printer body. FIG. 6 is a time chart showing a character selection process including shift selection. FIG. 4 shows an example of a conventional type serial printer. 1...Motor 2.5...Deceleration means 4...Select/Print trigger with magnet 5...
・・・・・・Shift trigger electromagnet 6・・・・・・・・・
Shift clutch 7...Shift cam 8...Shift cam driven body 9...
...Shift reset detector 1o...Print wheel group 11...Shift return spring 12...Print wheel axle 40...Print wheel selection camshaft and above Applicant Epson Corporation

Claims (1)

[Scope of Claims] A carriage held slidably in the digit direction, a type ring group held on the carriage so as to be rotatable and slidable in the rotational axis direction, and a type ring group that controls the rotation of the type ring group. a shift selection means for shifting the type wheel group by a predetermined distance with respect to the carriage; a spacing means for moving the carriage in the digit direction; a type position on the type wheel group and the type @ a sole detection means for detecting the shift position of the group; a transmission means for transmitting the rotation of the rotary shaft to the shift selection means; and an electromagnetic means for controlling the transmission means in response to a signal generated from the detection means. A type serial printer comprising: and.