JPS61295061A - Printing apparatus - Google Patents

Abstract

PURPOSE:To prevent the change of the stop position of a carriage even if a flexible medium member is stretched by a change with the elapse of time, by displacing either one of a detector and the member to be detected, which is detected by said detector, along with a support wheel. CONSTITUTION:A shutter 26 is inserted between the light emitting element and light receiving element of a photosensor 43 and the sensor 43 is turned ON to stop the movement of a carriage. A cam 33 is provided with a revolving habit always revolved to the counterclockwise direction in a drawing around a support shaft 36 by the force of a tensile spring 41 and constituted so as to respectively press both cam surfaces of plate cam parts 34, 35 to the shafts 27 provided to both sides of a pulley 29. A moving habit to the direction shown by an arrow is always imparted to the shafts 27 and constant tension is applied to a wire 32. When the wire 32 is stretched by a change with the elapse of time, position of the carriage changes from a curve (a) to a curve (b) and the position of the shutter also changes from (h) to (k). Therefore, the position (k) of the shutter is detected at the D-point on the curve (b) to turn a photosensor 43 ON and the carriage is stopped at the next step, that is, at a position (x).

Description

DETAILED DESCRIPTION OF THE INVENTION In this invention, a carriage reciprocates along a platen,
It can be applied to digital, thermal, thermal transfer, dot, and inkjet printers that sequentially print on paper set on a platen using a recording head mounted on a carriage, or to serial printing devices such as plotters and typewriters.

BACKGROUND ART Conventionally, this type of serial printing device is constructed as shown in FIG. 5, for example. The symbol (1) in the figure is the left side plate, and between it and the right side plate (not shown), the platen (2), guide shaft (3), support shirt 1- (4), and stem (5) are placed parallel to each other. It's going to be passed on. Thus, the guide shaft (3) and the support shaft (4) support the carriage (6). Both ends of the wire (7) are fixed to the carriage (6). Wire (
7) is stretched between the left and right pulleys (8) and (9).

The left and right pulleys (8) and (9) are each rotatably supported at both ends of the aforementioned rectangular frame-shaped stay (5). Then, the driving pulley (9) is rotated by the operation of the step motor (10).

The wire (7) is moved to cause the aforementioned carriage (6) to reciprocate along the platen (2). At this time, the recording head (11) mounted on the carriage (6)
) Printing is performed sequentially on the sheets (12) set in the paper (12).

By the way, in this type of printing device, conventionally, the left side plate (1)
A part of the shutter is cut out and bent outward to form a bent piece (13) as shown in Fig. 6, and the base end of the long plate-shaped shutter (14) is overlapped with the bent piece (13), and the fixing screw ( 15), it was fixed so as to be movable and adjustable, and its tip protruded into the main body of the device. Then, when the carriage (6) finishes printing one line and is cleared and returns to the left side of the main body of the device, the sensor mounted on the carriage (6) (
16) The shutter (14) is used to shut off the light emitting element and the light receiving element (see Fig. 6), and after the shutoff, the rotation of the step motor (10) is decelerated, and the carriage (6) was moved to the left end and stopped. Then, 1 in the printing direction (right direction in Figure 1).
The carriage (6) is moved intermittently in steps (carriage movement distance 1/120#) until the sensor (16) is disconnected, and then the next step position of the step motor (10) is determined. I had it stopped. Then, the stop position of the carriage (6) is set as the print start position. However, when the carriage (6) stops, it comes to a complete stop while performing a hunting operation (vibration damping). For this reason, the shutter (14
), the sensor (16) may or may not be deblocked, so the print start position may also be at the same point as the target position.
This is the case where the position is past the step (ie, 1/120#). Therefore, when a line changes, printed characters may be misaligned with the previous line, resulting in a problem of deterioration of print quality. Therefore, in the past, necessary adjustments were made as appropriate to prevent the positioning of the carriage (6) from becoming unstable.

However, in this conventional configuration, when the wire (7) stretches due to changes over time, etc., the above-mentioned adjustment becomes erroneous, and the step position varies before and after and stops.

There has been a drawback that the stop position of the carriage (6) is shifted and the printing start position, which is determined by moving the carriage (6) a certain amount from the stop position, is disturbed, leading to a deterioration in print quality.

For example, as shown by curve a in Fig. 4, the carriage (6)
detects the shutter position (h) at point A and sends the sensor (16)
Turn ON and stop at the next step, that is, position (A). However, as the wire (7) extends, the shutter position comes to near the stop position of the carriage (6), as shown in the curve, and the difference in the hunting operation when the carriage (6) stops causes the shutter to move as shown in Fig. 7(A). As shown in the curve above, the carriage (6) detects the shutter position i at point B and the sensor (1
5) is turned on and the shutter stops at the next step, that is, the mouth position, and there is a case where the shutter position is detected at the 0 point and the shutter stops at the position C as shown in FIG. 7(B). For this reason,
Character misalignment occurred between the previous line and the current line, reducing print quality.

Therefore, an object of the present invention is to absorb the slack due to the elongation of a bending media member such as a wire belt by the displacement of a support wheel such as a pulley or gear that spans and supports it. A serial printing device as described above, which drives a carriage via a bending media member, and when the carriage reaches a certain position, detects it with a detector such as a photosensor or microswitch and stops the movement of the carriage. In this case, even if the bending mediating member stretches due to changes over time,
The objective is to always maintain good print quality without causing a change in the stop position of the carriage due to its elongation, and without causing any disturbance in the print start position, for example.

Structure Therefore, in the above-mentioned type of printing device, the present invention is applicable to either a detector such as a photosensor (43) or a microswitch, or a member to be detected such as a shutter (26) detected by the detector. The structure is characterized in that the structure changes with the support wheels such as pulleys (29) and gears.

Hereinafter, this invention will be described in detail together with an embodiment of the invention shown in the drawings.

The printing device according to the present invention is basically the same as the conventional printing device shown in FIG. 5, for example, and the only difference is in the means for attaching a shutter (26), which will be described later.

That is, what is indicated by the reference numeral (20) in FIGS. 1 and 2 is a rectangular frame-shaped stay, which corresponds to the stay (5) used in the conventional printing device shown in FIG. Similarly, it spans between the left and right side plates of the main body of the device.

The stay (20) has opposing front and rear sides (21) and (2
2) Long holes (23) each extending in the length direction at one end.
- Drill (24) at the corresponding position, and below the elongated hole (23) on the front side thereof, make a fitting hole (25). and,
Fit the base end into the fitting hole (25), and
1) A shutter (26) is rotatably attached so as to overlap with the front side of the shutter. The shutter (26) is as shown in the figure.
It is bent into a crank shape, and the tip is separated from the side surface (21) and protrudes upward. The elongated hole (23) and (
24) Hang the headed shaft (27) between them and prevent it from coming out with the E-ring (28). The shaft (27) rotatably supports the pulley (29) between the side surfaces (21) and (22). The movement of the pulley (29) on the axis is similar to that of the shaft (29).
It is blocked by two E-rings (30) and (31) attached to 7). A wire (32) is hung on the pulley (29). The wire (32) corresponds to the wire (7) used in the conventional printing device shown in FIG. 5, and is stretched between the drive pulley (not shown) and attached to the carriage at both ends.

Now, the cam (33) is pressed against the shaft (27). The cam (33) has two parallel plate cam parts (34) and (35) formed at its tip by bending a plate member into a U-shape. And a support shaft (3
6) to support it rotatably. The support shaft (36) spans between the sides (21) and (22) of the stay (20),
E-ring (37) attached to its support shaft (36)
) and (38) restrict the axial movement of the cam (33) and prevent the support shaft (36) from being removed. Thus, the locking piece (39) extends toward the front from the base of the front side plate cam portion (34) of the cam (33). Then, attach the locking piece (39) to the side surface (21) of the stay (20).
It protrudes from an arcuate hole (40) drilled in the. Then, one end of the tension spring (41) is hung on the tip of the locking piece (39). The tension spring (41) is attached to the side (21) of the stay (20).
, and hang the other end on the locking pin (42). The locking pin (42) stands on the side surface (21).

On the other hand, a photosensor (43) is attached to the carriage to which the driving force of the step motor is transmitted via the wire (32). When one line of printing is completed and the carriage is cleared and the carriage returns to the starting position on the left side of the main body of the device -9-^1, the photosensor (43) as shown by the dotted chain line in Figure 1. A shutter (26) is inserted between the light emitting element and the light receiving element, turning on the photosensor (43) and stopping the movement of the Kiraridge.

Therefore, the cam (33) is always given the habit of rotating counterclockwise in the figure around the support shaft (36) by the force of the tension spring (41), and both cams of the plate cam parts (34) and (35) The surfaces are pressed against the shafts (27) on both sides of the pulley (29), respectively, as shown in FIG. Then, the shaft (27) is given the habit of always moving in the direction of the arrow in Fig. 3,
Apply constant tension to the wire (32).

Therefore, if the wire (32) stretches due to changes over time, etc.

The slack of the wire (32) due to its elongation is
9) is absorbed by the displacement. When the shaft (27) moves inside the long holes (23) and (24), the shutter (26)
is rotated counterclockwise in FIG. 1 about the base end. Therefore, when the wire (32) extends, the pulley (2
9) moves, and the shutter (
26) will also be displaced.

Therefore, when the wire (32) extends, the carriage position changes from the curve a to the curve as shown in FIG. 4, and the shutter position also changes from h to k. Therefore, the shutter position is at point D on the curve! (k) is detected, the photo sensor (43) is turned ONL, and the carriage is stopped at the next step, that is, the position (a). Therefore,
The starting position is the same as before the wire (32) was extended.
According to this invention, even if the wire (32) stretches, the printing start position will not be disturbed.

In the illustrated embodiment, a wire (3
Although the case where 2) is used has been described, it is not limited to wires, but may be belts, etc., and the support wheels supporting them are not limited to pulleys, but may also be gears, etc.

Further, in the above-described embodiment, the photo sensor (43) is activated by the shutter (26) to detect ONL and the return of the carriage to the starting position. However, the return of the carriage can be detected not only by a photosensor but also by, for example, a microswitch.

Furthermore, in the embodiment described above, the shutter (26), which is the member to be detected, is configured to be displaced together with the pulley (29), which is the support vehicle. However, not only the detected member but also a detector such as a photo sensor or a microswitch can be configured to be displaced together with the support vehicle.

Effects Therefore, according to the present invention, in a serial printing device in which the slack due to the elongation of the bending medium member is absorbed by the displacement of the support car that spans and supports the bending medium member, the sensor or the object detected by the sensor is Since one of the detection members is configured to be displaced together with the support vehicle, even if the bending mediating member stretches due to changes over time, the stop position of the carriage will not change due to the stretching, and for example, the printing start position will not be disturbed. The print quality can always be kept good without causing any problems.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a main part of a printing device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is an explanatory diagram of a mechanism for applying tension to the wire. FIG. 4 is a timing chart illustrating the invention in detail. Fifth
The figure is a partial perspective view of a conventional printer body, and FIG. 6 is a partially exploded perspective view thereof. FIGS. 7(A) and 7(B) are timing charts explaining the conventional operation.

Claims (1)

[Claims] 1. The slack caused by the stretching of the bending mediating member is absorbed by the displacement of a support car that spans and supports it, and the driving force of the step motor is transmitted to the carriage via the bending mediating member. In a serial printing device in which the carriage is moved by moving the carriage, and when the carriage reaches a certain position, the position is detected by a detector and the movement of the carriage is stopped, the detector or the detected object detected by the detector is used. A printing device configured to displace one of the members together with the support wheel. 2. The bending mediating member is a wire, and the wire is stretched between pulleys, and the slack due to the wire's stretching is absorbed by the displacement of the pulley, and the driving force of the step motor is transmitted to the carriage via the wire. The printing device according to claim 1, wherein the carriage is moved by: 3. A shutter is used as the member to be detected, and the shutter is configured to be displaced together with the support vehicle, and when the carriage comes to a certain position, a photosensor on the carriage detects the shutter and the movement of the carriage is stopped. A printing device according to claim 1. 4. When the carriage finishes printing one line and is cleared and returns to the starting position, the position is detected by a detector and the movement of the carriage is stopped, as set forth in claim 1. printing device.