JPH0736758Y2 - Home position detection mechanism of printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field of application The present invention can be applied to, for example, a printer / typewriter, and in particular, while moving a carriage along a platen, a print wheel is sequentially rotated to a desired type. Can be applied to a daisy-serial type printing device that sequentially hits the selected characters with a hammer and hits the platen via a printing ribbon to sequentially print on the paper on the platen. More specifically, the present invention relates to a home position detection mechanism for detecting the space home position of the carriage and the selection home position of the print wheel in such a printing apparatus.

2. Description of the Related Art Conventionally, this type of home position detection mechanism has been used in a printer.
For example, it was provided as shown in FIGS. 6 and 7.
That is, the detection sensor (2) for detecting the space home position of the carriage (1) is fixedly arranged inside the apparatus body, for example, by being attached to a frame (not shown), and the shutter (3a) for opening and closing the detection sensor (2). )
Of the carriage frame (3) protruding from the side of the carriage frame (3), and a detection sensor (5) for detecting the selection home position of the print wheel (4) separately.
Is fixed to the carriage frame (3) and a shutter (6) for opening and closing the detection sensor (5) thereof is formed so as to project from the boss portion (4a) of the print wheel (4). That is, in the conventional home position detecting mechanism, the space home position detecting sensor (2) and the print wheel selection home position detecting sensor (5) are separately provided. For this reason, since two detection sensors are required, there is a drawback that the cost is high.

Therefore, in the conventional home position detecting mechanism of this type, as shown in, for example, Japanese Utility Model Laid-Open No. 59-79346, a single detection sensor shares both the space home position detecting sensor and the selection home position detecting sensor. It is proposed to fix it on the carriage.

However, in such a home position detection mechanism, since the detection sensor is fixed on the carriage, the carriage moves while dragging the sensor signal line, which is unreliable. It was

Therefore, an object of the present invention is to solve such a problem in the home position detecting mechanism of the daisy serial printer described above, to reduce the cost, and to improve the reliability thereof.

Therefore, the home position detecting mechanism according to the present invention sequentially moves the print wheel (26) while moving the carriage (15) along the platen (10), for example, as shown in the illustrated embodiments below. ) Is rotated to select a desired type (26a), the selected type (26a) is tapped with a hammer (27), and is struck on the platen (10) through the print ribbon (28). ) In a daisy-serial printing device that sequentially prints on the upper paper (22), a detection means such as a transmissive photosensor (23) is fixedly arranged in the main body of the device, and the carriage (15) is unidirectionally arranged. The first actuating member such as a space shutter (29) which operates the detecting means at the first point A to generate a detection signal when the first point A is reached. Land of When the carriage (15) is continuously moved in the same direction from A and reaches the second point B, the print wheel (26) is rotated at the second point B, and the print wheel (26) is rotated in conjunction with the rotation. A second actuating member such as a selection shutter (30) for actuating the detecting means to generate a detection signal is attached to the carriage (15) together.

Action Then, at the first point A, the detection means is operated by the first actuating member to generate a detection signal, and the space home position is determined with reference to the point A, and the print wheel at the second point B. (26) is rotated, the detection means is operated by the second actuating member at a predetermined rotational position within one rotation, a detection signal is generated, and the selection home position is determined with reference to the position.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 3 shows a daisy serial printer having a home position detecting mechanism according to the present invention. Reference symbol (1
Reference numeral 0) denotes a round platen, which is formed by straddling both ends of the platen shaft (10a) between the left and right side plates (11) and (12) facing each other. A support shaft (13) and a guide rail (14) are also laid between these side plates (11) and (12) so as to be parallel to the platen (10). The support shaft (13) and the guide rail (14) support the carriage (15). A timing belt (16) is attached to the carriage (15). The timing belt (16) consists of left and right drive pulleys (17) and driven pulleys (18).
Hang in between. The drive pulley (17) is attached to the motor shaft (20) of the space motor (19) fixed to the right side plate (12). Then, the drive pulley (1
7) is rotated, the timing belt (16) is moved, and the carriage (15) is guided by the support shaft (13) to reciprocate along the platen (10). At this time, the print head (21) mounted on the carriage (15) sequentially prints on the paper (22) on the platen (10).

By the way, in the apparatus main body of such a printer, for example, at the left end, a transmissive photosensor (23) is fixedly arranged by being attached to a frame not shown.

1 and 2 are enlarged views of the carriage (15) portion of the printer described above. Reference numeral (24) in the figure denotes a carriage frame, the front and rear of which are supported by the support shaft (13) and the guide rail (14). Then, a selection motor (25) is attached to the center of the carriage frame (24) and its motor shaft (25a) is attached.
To the platen (10) side, and attach the print wheel (26) to the tip in a detachable manner. Then, the print wheel (26) is rotated by the selection motor (25) so that the desired type (26a) can be appropriately selected. In addition, attach the hammer (2
7) Attach. Then, with the hammer (27), the selected character (26a) is tapped and tapped on the platen (10) through the print ribbon (28), and it is possible to sequentially print on the paper (22) on the platen (10). To do.

A space shutter (29) is attached to such a carriage frame (24) on one side of the front surface (24a). The space shutter (29) interrupts the photo sensor (23) at a first point A, which will be described later, within the movement range of the carriage (15), generates a detection signal to the photo sensor (23), and moves the point A to that point. Determine the space home position of the carriage (15) as a reference. On the other hand, the print wheel (26) described above is provided with a selection shutter (30) extending from the boss (26b). The print wheel (26) and the rotation axis thereof, that is, the motor shaft (25a) can be rotated. The selection shutter (30) shields the photo sensor (23) by blocking the photo sensor (23) as the print wheel (26) rotates at a second point B which will be described later in the movement range of the carriage (15). A detection signal is generated, and the selection home position of the print wheel (26) is determined with reference to the rotation position thereof.

4 and 5 show the operation of the home position detecting mechanism in the daisy serial printer described above. That is, it is assumed that the carriage (15) is now at the position indicated by 1) in FIG. 5 with respect to the platen (10). At this time, for example, when the power is turned on or a restore (initialize) instruction is input from the host, first, as can be seen from the flow chart shown in FIG. 4, first move the carriage (15) to the carriage shown in FIG. 5).
Moves in the TAB direction indicated by the middle arrow a by an arbitrary distance. Then, the carriage (15) is slowly moved in the CR direction indicated by the middle arrow b in Fig. 5 (2), and when the center reaches the point A, the space shutter (29) stops when the photo sensor (23) is blocked. . Then, the first point A in the moving range of the carriage (15) is used as a reference for determining the space home position.

After that, the carriage (15) is again moved in the CR direction, and the point A is used as a reference to advance the distance N _{1 as} shown in FIG.
Stop when the center of the carriage (15) reaches point B. This distance N ₁ is the distance between the selection shutter (30) and the above-mentioned space shutter (30) on the carriage (15) when the selection shutter (30) is just facing downward, that is, in the state shown in FIG. 29) and the horizontal distance (distance parallel to the platen axis (10a)). Then, at this point B, the selection motor (25) is driven to rotate the print wheel (26), and when the print wheel (26) reaches a predetermined rotation position during one rotation, that is, the selection shutter (3
When 0) reaches a position that blocks the photo sensor (23), stop at that position. Then, this rotational position is set as the selection home position.

After that, move the carriage (15) again in the TAB direction,
Based on the above-mentioned point B, the distance N ₂ from the point B, that is, the distance N ₃ (= N ₂ −N ₁ ) from the point A, is advanced to the position shown in FIG. 5). Then, this position is set as the space home position of the carriage (15).

By the way, in the illustrated embodiment described above, the transmissive photosensor (23) is used as the detection means, and the space shutter (29) and the selection shutter (which open and close the photosensor (23) as the first and second actuating members. 30) and when using. However, with this device,
Instead of these, for example, a reflection type photosensor may be used as the detection means, and a reflection plate that opens and closes the photosensor may be used as the first and second actuating members, and a magnetic sensor may be used as the detection means. A magnet for opening and closing the magnetic sensor may be used as the first and second actuating members, and a contact may be used as the detecting means.
It is also possible to use mechanical actuating members which mechanically open and close their contacts as the first and second actuating members.

Therefore, according to this invention, the detecting means is fixedly arranged in the main body of the apparatus, and the detecting means is shared to detect both the space home position and the selection home position. ) Etc. need only one detection means,
The cost can be reduced. Further, since the detecting means is not mounted on the carriage, the carriage does not move while dragging the signal line as in the conventional case, and the reliability can be improved.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention in which a home position detecting mechanism according to the present invention is applied to a daisy serial printer, and FIG. 1 is a front view of the carriage portion viewed from the platen side. 2, FIG. 2 is a side view of the carriage portion, FIG. 3 is an overall schematic plan view of the internal mechanism of the printer, FIG. 4 is a flowchart showing the operation of the home position detecting mechanism in the printer, and FIG. 5 is its operation. It is an explanatory view explaining. 6 and 7 are a front view and a side view of a carriage portion showing a conventional home position detecting mechanism. (10) …… Platen (15) …… Carriage (22) …… Paper (23) …… Transmissive photo sensor (detection means) (25a) …… Motor shaft (rotating shaft) (26) …… Print wheel ( 26a) …… Type (27) …… Hammer (28) …… Print ribbon (29) …… Space shutter (first actuation member) (30) …… Selection shutter (second actuation member) A …… Point 1 B. Second point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Open 59-79346 (JP, U) Open 61-112953 (JP, U) Open 61-130431 (JP, U)

Claims (6)

[Scope of utility model registration request] 1. A carriage is moved along a platen to sequentially rotate a print wheel to select a desired type, hit the selected type with a hammer, and hit the platen via a printing ribbon. In a daisy serial printing apparatus for sequentially printing on the above paper, the detecting means is fixedly arranged in the apparatus body, and when the carriage is moved in one direction to reach a first point, the first point When the carriage is moved in the same direction from the first point to the second point when the carriage is moved from the first point to the second point, the second point is set at the second point. And a second operating member that rotates the print wheel and rotates in conjunction with the rotation to operate the detection means to generate a detection signal. Home position detecting mechanism comprising Te printer. 2. The utility model registration claim wherein the detecting means is a transmissive photosensor, and the first operating member and the second operating member are shutters for opening and closing the photosensor. The home position detection mechanism of the printing device according to the item. 3. The utility model registration claim, wherein the detection means is a reflective photosensor, and the first operating member and the second operating member are reflectors for opening and closing the photosensor. The home position detection mechanism of the printing apparatus according to item 1. 4. The utility model registration claim 1, wherein the detecting means is a magnetic sensor, and the first operating member and the second operating member are magnets for opening and closing the magnetic sensor. Home position detection mechanism of the printer. 5. The utility model registration claim, wherein the detecting means is a contact, and the first operating member and the second operating member are mechanical operating members that mechanically open and close the contact. The home position detection mechanism of the printing apparatus according to item 1. 6. The utility model registration claim 1, wherein the first operating member is fixed to a carriage frame and the second operating member is fixed to a boss portion of the print wheel. Home position detection mechanism for printer.