JPS62170379A - Ribbon-shifting mechanism for printer - Google Patents

Abstract

PURPOSE:To simplify a mechanism for detecting a home position of a multicolor ribbon cassette and prevent the cassette and a paper bail from interfering with each other, by a construction wherein a controlling gear in a ribbon-positioning mechanism comprising a controlling circuit is provided with a home position indicating light-passing hole to be detected by a photo-sensor. CONSTITUTION:A ribbon-controlling shaft 17 is rotated under control by rotating a pinion 19 of a color-selecting motor 18 through a controlling gear 21. The gear 21 is provided with a home position indicating light-passing hole 21a, and the rotation of the gear 21 is detected by a photo-sensor 22. When a multicolor ribbon cassette 23 is located above a home position H0 and when, for example, a color track IV is selected, turning ON a micro-switch 33 by pulling a paper release lever 32 causes an initial operation of moving the cassette 23 from the position IV to I II H0, thereby avoiding interference with a paper bail 28, and then a plunger magnet 30 is excited to separate the paper bail 28 from a platen 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention involves mounting a multicolor ribbon cassette containing multicolor ribbons on a carrier that moves along a platen, and printing the multicolor ribbons by a print head held by the carrier. The present invention relates to a ribbon switching mechanism for switching the color track of a multicolor ribbon by shifting a multicolor ribbon cassette up and down in a printer that prints multicolors on intermediary paper.

Prior Art Conventionally, there have been two types of ribbon switching mechanisms of this type: one that performs switching based on the suction operation of a plurality of magnets, and the other that performs switching based on the rotation of a motor.

However, in the former case, as the number of color tracks in the multicolor ribbon increases, the number of magnets and mechanical parts increases, and reliability is also low.

On the other hand, in the latter case, the home position of the multicolor ribbon cassette was detected by detecting the slit of the slit disk with a photo sensor, but the slit disk was designed exclusively for such detection, and the lψffl+ system It was provided separately from the gear.

Therefore, if the slit disk and the gears of the drive system are assembled out of phase, an error occurs in the stopping position of the multicolor ribbon cassette. Further, not only is it troublesome to adjust the gear and the slit disk, but the number of parts increases, which is unfavorable in terms of cost.

In addition, when the ribbon cassette was initialized when the paper bail was open, the paper bail and ribbon cassette interfered, resulting in damage to them, but this was dismissed as an operator error. As a machine, it had no protection.

An object of the present invention is to simplify a mechanism for detecting the home position of a multicolor ribbon cassette, and to perform initial control such that the ribbon cassette and paper bail do not interfere with each other.

Structure As shown in FIG. 2, the present invention relates to a control gear (21) that is rotated by a color select motor (18) and constitutes a drive system of a ribbon positioning mechanism.

A transparent hole (21a) for indicating the home position is provided, which is detected by the photosensor (22), and a ninth
The present invention is characterized by comprising a control circuit that controls the ribbon positioning mechanism in conjunction with the paper bail operating mechanism as shown in the figure.

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, a carrier (10) is supported by two front and rear guide rods (11) and (12) so as to be slidable left and right, and moves along a platen (13). A print head (14) is located at the front (platen side) of this carrier (10).
is installed. In addition, left and right brackets (10a) are attached to both rear left and right ends of the carrier (10).
), and these brackets (10a)
In between, the mounting plate (15) holds the left and right protruding pins (
15a) so as to be vertically movable.

This support point is at the same height as the axis of the platen (13).

A cam follower (15b) is protruded from the lower part of the mounting plate (15), and the cam follower (15b)
) is slidably engaged with an annular groove track portion (16a) provided on the side surface of a ribbon control cam (16) that moves together with the carrier (10). The ribbon control cam (16) connects the guide rods (11) and (1)
Although it can slide left and right with respect to the ribbon control shaft (17) parallel to 2), it cannot rotate around it, but rotates integrally with the ribbon control shaft (17). The ribbon control shaft (17) is
As shown in FIG. 2, the idle gear (20) and control gear (2
The rotation is controlled via 1). Control gear (21
) is detected by a photosensor (22) as described below.

When the color select motor (18) rotates forward or backward, the ribbon control cam (16) rotates clockwise or counterclockwise, and the mounting plate (15) rotates upward or downward, and the mounting plate (15) can be attached or detached thereon. The multicolored ribbon cassette (23) placed on is shifted upward or downward.

The mounting plate (15) is provided with a spring-loaded cassette lock pawl (not shown), which holds the multicolored ribbon cassette (23) in place on the mounting plate (15). Ru.

The multicolor ribbon cassette (23) stores, for example, a four-color ribbon (25) formed by dividing four color tracks (I), (n), (m), and (IV) into the same width in the width direction. has been done. Further, the multicolor ribbon cassette (23) is equipped with a ribbon feed gear (23a), and this gear (23
a) by rotating it with a ribbon feed mechanism (not shown) provided on the mounting plate (15),
The four-color ribbon (25) is transported.

Also, the paper bail (28) that presses the paper (27) against the platen (13) is moved from the closed position shown by the solid line in FIG.

It can be displaced to the open position shown by a dashed line by an operator's operation.

FIG. 3 shows the phase relationship between the groove track portion (16a) of the ribbon control cam (16) and the cam follower (15b). Here, when the cam follower (15b) is at the home position (Ho), in the case of the multicolor ribbon caster (23), the boundary line between the color tracks (II) and (III) is at the same height as the axis of the platen (13). This is the home position of the multicolor ribbon cassette (23) itself. The lift height of the ribbon control cam (16) is at the home position (HO).
), there is no displacement in the range of θa in both directions, that is, in the range of H' to H'. On the other hand, the lifting height in the range of 1 position 5dtz to H' and H' to Sup is a linear displacement, and the selection positions of color tracks (1) to (IV) are in this range. In addition, (I) to (II) and (III) to (I
The rotation angle of V) is the same θis, but the rotation angle of (n) to (I
During II), there is a no-displacement range θa, so the rotation angle is (
ois+θa), but this displacement amount is (1) to (I
The amount of displacement is the same as in I) and (m) to (IV). When these positions are viewed in order clockwise, Sdw-
+(1)+(TI)→(Ho)→(m)n(IV)+
The Sup range is an ascending portion, while the Sup→Sdv range is a descending portion.

FIG. 4 shows the control gear (21) that rotates integrally with the ribbon control cam (16). This gear (2
1), there is a transparent hole (21) for indicating the Baum position with an arc length of angle Oa as a mark corresponding to the home position (Ho).
a) is drilled. When the control gear (21) is stopped at the home position (Ho), the optical axis of the photosensor (22) faces the center of the transparent hole (21a), and the control gear is moved from this home position 1f (Ho). (2
1) rotates clockwise, the photosensor (22) faces the part without the light-transmitting hole (21a) and is shielded from light.

At this time, the multicolor ribbon cassette (23) is shifted downward, ie in the direction in which color tracks (I) and (TI) are selected. On the other hand, control gear (21) is in the home position! When rotated counterclockwise from (HO), the multicolor ribbon cassette (23) is moved upward, that is, the color track (m
) and (IV) are shifted in the selected direction.

FIG. 5 shows the relationship between the rotation angle of the ribbon control shaft (17), the lifting height of the ribbon control cam (16), the output of the photosensor (22), and the selected position of the multicolored ribbon (25).

The color selection motor (18) is controlled by a control circuit (not shown) to control the light transmission hole (
Control is performed according to the detection of 21a).

FIG. 6 shows the flow of the initial homing operation (home position detection operation). Here, the photosensor (22)
"Bright" refers to the state in which the light passes through the transparent hole (21a), and "dark" refers to the state in which light is blocked. In addition, in order to rotate the ribbon control shaft (17) by θa and Ois, the color select motor (18) is rotated by na(
Even number) steps, nis steps shall be rotated.

The color select motor (18) is connected to the multicolor ribbon cassette (
23) in the direction of raising the photo sensor (22).
) changes from "dark" to "bright", the color select motor (18) further rotates by na/2 steps and then stops. This is the home position (HO) of the multicolor ribbon cassette (23). Switching after detecting the home position is the fifth
When going from the rotation angle to the arbitrary position shown in the figure, that is, from the home position (HO) to (1), the color select motor (18) rotates in the downward direction in steps of (na/2+nis/2+n1s). When shifting from (1) to (TI), it rotates in the nfs step upward direction.

FIG. 7 shows the case when the color track (I) of the multicolor ribbon (25) is selected, and FIG. 8 shows the case when the color track (■) is selected.

FIGS. 9 to 11 show a paper bail operating mechanism for operating the vapor bay nozzle 28). The paper bail lever (29) is connected to the rod (31) of the plunger magnet (3o). Paper release lever (3)
When 2) is pulled from the solid line position to the Iri line position (counterclockwise) in Fig. 9, the microswitch (33) is turned on, the plunger magnet (30) is energized, and the rod (31) is attracted in the R direction. and the paper bail lever (
29) is rotated in the S direction against the spring (34), and the paper bail (28) is separated from the platen (13). In addition to turning on and off the microswitch (33), the plunger magnet (3o) is also used to turn on and off the photo sensor (22).
) is controlled by a control circuit (not shown) based on the detection of When track (m) or (IV) is selected, even if the paper release lever (32) is pulled and the microswitch (33) is turned on, the plunger magnet (30) is not immediately energized. That is, for example, if the paper release lever (32) is pulled as described above when the color track (IV) is selected, the multicolor ribbon cassette (23) will move from the (TV) position to the (1) position in FIG. )→(■)→(Ha), and interference with the paper bail (28) is avoided. The plunger magnet (30) is then energized and the paper bail (28) moves away from the platen (13).

When the printer is powered off, open the top cover (35) as shown in Figure 11 and press the paper release lever (35).
2) further counterclockwise from the position shown in FIG. At this time, the paper bail (28) is pushed away from the platen (13) by the paper release lever (32).

In this case, even if the power of the printer is turned on, a cover open error state will occur, so the initial operation of the multicolor ribbon cassette (23) will not be performed.

Effects As explained above, in the present invention, since the transparent hole for detecting the home position of the multicolor ribbon cassette is provided in the control gear of the drive system, the detection accuracy is not only high, but also the configuration is simple. In addition to being easy to adjust, it is also inexpensive.

In addition, even if the paper bail is left open due to an operator error and the initial operation is performed, the multicolored ribbon cassette can be controlled to retreat, thereby avoiding interference between the paper bail and the multicolored ribbon cassette, ensuring safety. You can also plan.

[Brief explanation of drawings]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a side view of its drive system, and FIG. 3 is an explanatory diagram showing the phase relationship between a ribbon control cam and a cam follower. Figure 4 is a side view showing the arrangement of the transparent holes of the control gear, and Figure 5 shows the relationship between the rotation angle of the ribbon control shaft, the lifting height of the ribbon control cam, the output of the photosensor, and the selected position of the multicolored ribbon. FIG. 6 is a flow chart of the initial homing operation, and FIGS. 7 and 8 are side views showing the selection state of the color track of the multicolor ribbon cassette. 9 to 11 are side views showing different states of the paper bail operating mechanism. (10)...Carrier (13)...Platen (14)...Print head (17)...
...Ribbon control shaft (18)...
...Color selection motor (21)...
...Control gear (21a)...
・Transparent hole for home position indication (22)...
Photo sensor (23)...Multicolor ribbon cassette (25)...Multicolor ribbon (27)
・・・・・・Paper (28)・・・・・・Paper bail (30)・・・
・・・・・・Plunger magnet Fig. 1 Fig. 2 Fig. 7 Fig. 8 If to 15b 16a
16Figure 10Figure 11

Claims (1)

[Claims] A multicolor ribbon cassette containing multicolor ribbons is mounted on a carrier that moves along a platen, and the multicolor ribbon cassette is shifted up and down by a ribbon positioning mechanism driven by a color select motor to position the multicolor ribbon. death,
In a printer that prints multicolor printing on paper via the multicolor ribbon by a print head held in a carrier, a control gear rotated by the color select motor and forming a drive system of the ribbon positioning mechanism is detected by a photo sensor. 1. A ribbon switching mechanism for a printer, comprising: a transparent hole for indicating a home position; and a control circuit for controlling the ribbon positioning mechanism in conjunction with a paper bail operating mechanism upon detection of the transparent hole.