JPS6242845A - Daisy serial printer - Google Patents

Abstract

PURPOSE:To lessen the effect of temperature change, prevent the occurrence of noise, and raise durability of a daisy serial printer by providing a thrust ball bearing between a plate spring and a type wheel. CONSTITUTION:The basal end of a plate spring 136 is attached to the front of a front frame 134, and a thrust ball bearing 138 is attached to the tip end of the plate spring 136. The outer ring 138a of the bearing 138 is fixed to the spring 136, and an inner ring 138b as a movable ring with a ball 140 is fixed to a wheel receiving shaft 142 piercing the center of the inner ring 138b. A contact plate 144 is integrally formed with the shaft 142. The contact plate 144 comes into contact with the spring contact projection 22 of a type wheel 14, and thereby the wheel 14 inside a cassette case 12 is pushed backwards. The engagement between a crown tooth 30 and a crown gear 128 can thus be secured.

Description

[Detailed Description of the Invention] Technique WF - This invention uses a type wheel, and rotates the type wheel with a selection motor while moving a carriage along a platen to appropriately select desired type. The present invention relates to a digital serial printing device such as a digital serial impact printer, which sequentially prints on sheets of paper loaded onto the platen by successively hitting printed characters with a printing hammer and hitting the printed characters against a platen via a ribbon.

Prior Art Conventionally, this type of printing device has had a structure as shown in FIG. 9, for example. Reference numeral (1) in the figure is a selection motor, which is attached to a motor bracket (3) that is swingably supported by a carriage frame (2), and is movable in the direction of the arrow in the figure. The motor shaft (
A crown gear (1b) is provided at the tip of 1a), and as shown in the figure, it can be freely engaged with and disengaged from the front teeth (4a) of the type wheel (4).

The type wheel (4) is housed in a cassette case (5) and is detachably attached to a cassette holder (6). The cassette holder (6) is swingably attached to the carriage frame (2) together with the motor bracket 3).

A front frame (7) is also attached to the carriage frame tz (2). Front frame (7)
The base end of the leaf spring (8) is attached to. and,
The leaf spring (8) has a wear-resistant material (9) fixed to its tip, presses it against the spring contact protrusion (4b) at the center of the type wheel (4), and connects mm (4a) on the other side to the motor shaft (1a). ) in the crown gear (1b).

However, in this type of conventional printing device, the type wheel (4) rotates while being in contact with the wear-resistant material (9), so if there are variations in the strength of the leaf spring (8), For example, when the leaf spring (8) is weak, the mm (4a) of the type wheel (4) and the crown gear (1a) of the motor shaft (1a)
1b) becomes insufficient, and on the other hand, when the engagement is strong, the rotational load on the type wheel (4) increases, causing an error in the stop position.

■ Deterioration over time due to friction is unavoidable, and there are problems with durability.

■ It produces fricative sounds and is noisy.

■ Easily affected by temperature changes.

There were drawbacks such as.

Therefore, an object of the present invention is to press the center of rotation of a type wheel against the motor shaft of a selection motor by applying force with a leaf spring, and to rotate the type wheel with the selection motor. In the digital serial printing device, which selects the desired type one after another and prints by hitting the selected type with a printing hammer, trouble does not occur even if there are slight variations in the elastic force of the leaf spring, and the durability is improved. The goal is to be rich in energy, quiet, and less affected by temperature changes.

Therefore, in the present invention, the type wheel (14) is urged by the leaf spring (36) and connected to the selection motor (64), and the selection motor (64) rotates the type wheel (14). A digital serial printing device that sequentially selects the desired type (20) and hits the selected type (20) with a printing hammer (70) to sequentially print,
It is characterized by a thrust ball bearing (1, 38) interposed between the leaf spring (136) and the type wheel (14).

Then, the type wheel (14) is energized by the leaf spring (136), and the selection motor (64) and the type wheel (14) are energized.
4), and also eliminates friction to make the rotation of the type wheel (14) smooth.

Hereinafter, the present invention will be described in detail based on an embodiment of the present invention shown in the drawings.

2 to 8 each show each part of a serial impact printer which is an embodiment of the present invention. What is indicated by the reference numeral (10) in the figure is a wheel cassette.

Wheel cassette (10) is a cassette case (12)
A type wheel (14) is housed inside.

As can be seen from Figures 2 (A) and (B) and Figure 3, the type wheel (14) has a central circular hub (4 parts (16)) and a plurality of parts extending radially from the hub part (16). It consists of a part of the finger (18)... and a type (20) attached to the tip of each part of the finger (18). and,
On the surface of the hub part (16), there is a cylindrical spring contact protrusion (22) at the center, and a cylindrical circular protrusion (24) is concentrically formed on the outer periphery of the spring contact protrusion (22).

On the other hand, a circular protrusion (28) is provided in the center on the back side,
mm (30) is formed on its top surface. And mm(
30) Home position detection mark (26) at one position on the outside
is attached.

On the other hand, the cassette case (12) is made of, for example, transparent As.
It consists of a front plate (32) and a back plate (34) made of resin.

As can be seen from FIGS. 2A and 2B and FIG. 4, the back plate (34) has a [J] notch (36) on one side and a circular hole (38) in the center. A circular frame (40) is provided on the front side, and a wheel cassette storage space (
42) and its wheel force set 1 to storage space (4
2) Counterbore the inner outer periphery and provide an annular relief (44) on the second side. A front plate (32) is attached to the front side of such a back plate (34). The top plate (32) covers about two-thirds of the lower part of the back plate (34) and is open at the top. Then, I-plate (3
A circular hole (52) with a smaller diameter is formed at a position corresponding to the circular hole (38) of 4). The circular hole (52)
Next to the above-mentioned Ho 11 position detection mark (26)
The detection window (54) should be opened squarely. This top plate (32
) is formed with an annular bank (56). The bank (56) is part of the finger of the type wheel (14) (]
8) It comes into contact with...

Therefore, there is a type wheel (1) inside the cassette case (12).
4), a circular protrusion (28) will be inserted into the circular hole (38).
) and the circular protrusion (24) fit into the circular hole (52) with a slight allowance.

Then, the outer peripheries of the circular protrusions (28) and (24) are connected to the circular holes (
A type wheel (14) is supported within its cassette case (12) in contact with the inner periphery of 38) and (52), respectively. At this time, part of the fingers of the type wheel (14) (
18) ... is in contact with the annular bank (56) of the cassette case (12), and the front side of the type (20) ... is not in contact with the back side of the top plate (32). There is. Also, since the back plate (34) has an annular relief (44), the back surface of the type (20) is also covered by the back plate (34).
It is designed so that it does not come into contact with the front side of the As the type wheel (14) rotates, the type wheel (14) rotates.
4) The detection mark (2G) is
) is housed so that it can be seen through the detection window (54).

- The above-mentioned wheel cassette (10) is mounted on the cassette holder (
62). And type wheel (14
) is connected to a selection motor (64), which rotates the type wheel (14). As is known, the carriage (60) is guided by the support shaft (66) and moves along the platen (68), and at the same time, the selection motor (64) sequentially selects the desired type and prints the selected type. By striking with a printing hammer (70), the type is struck against the platen (68) via the ink ribbon (72), and the paper (
74) can be sequentially printed.

By the way, as can be seen from FIG. 6, the cassette holder (62) has a cylindrical bearing part (
76), a rectangular frame-shaped frame 11 portion (78) extending upward from the bearing portion (76), and the frame portion (78).
) consists of arm-shaped holder parts (80) and (82) that hold the wheel cassette (10) on both front sides of the wheel cassette (10).

The frame portion (78) of such a cassette holder (62)
) is screwed into the hammer bracket (84). The above-mentioned printing hammer (70) is fixed to the hammer bracket (84), and the carriage (6) is fixed to the hammer bracket (84).
Type (20) on type wheel (14) attached to 0)
The back surface can be tapped through a notch (36).

On the other hand, the bearing portion (76) of the cassette holder (62) has a
As shown in FIG. 5, the lower front end of the carrier frame (86) rests on it. The carrier frame A (86) has a bottom frame (88) with an L-shaped bottom, and side frames that stand up from both sides of the bottom frame and whose standing height gradually decreases toward the rear. 8= The rear frame A (90) and (92) and the rear frame A (94) which stands up from the rear end of the bottom frame 15 are made integrally.

A roller (96) is rotatably attached to the rear frame (94). The roller (96) is attached to the platen (
Support stay (9s)-1- arranged in parallel with 68)
and rolls on the support stay (98).

Therefore, the carriage (60) is connected to the support 1-axis (66).
and the support stay (98), and the platen (6
8).

In addition, the side frames k (90) and (92) of the carrier frame (86) described above are provided with circular arc holes (100) and (1
02) can be opened. Those circular arc holes (100)・(+
02), a connecting shaft (104) is inserted therein. The child connection axis (104) is n? The cassette holder (62
) through the through hole (106) at the tip of the frame part (78). Furthermore, the connecting shaft (+04) is connected to the motor bracket 1.
- Pass through the connecting holes (110) and (112) on both sides of (108). The motor bracket (+08) has an arm (114) extending rearward from one side, and an engagement pin (1] 6) is attached to the tip of the arm (114). Engagement pin (1
16) enters the elongated hole (118) made in the one side frame (90) of the carrier frame (86) described above.

The elongated hole ([8) is located slightly behind the arcuate hole (100) described above, and is opened linearly in the horizontal direction. Therefore, the motor bracket (10g) is suspended from the carrier frame (86) by the connecting shaft (104) and the engagement pin (116), and is connected to the arcuate holes (100) and (102) and the elongated hole (1).
18) so that it can move in a direction perpendicular to the platen (68). Therefore, at both ends of the connecting shaft (104), the other end is the fixing pin (1,
One end of the toggle spring (122) is hung on the toggle spring (122) (see Figure 5), and the motor bracket (108) is placed either in front or behind the arc holes (100), (+02) and the long hole (118). It will be pressed against. In the drawings, FIG. 5 shows a state in which it is pressed forward, and FIG. 7 shows a state in which it is pressed backward.

By the way, such a motor bracket (108) is provided with a plurality of mounting holes (124), and screws () are inserted through the mounting holes (124).
The selection motor (64) mentioned above (not shown)
can be installed. The motor shaft (1) of the motor (64)
26) passes through the motor bracket (1,08) and attaches a crown gear (+28) to the tip. And the crown gear (
128) is pushed by a toggle spring (+22) and engages with the crown surface (30) of the type wheel (14) when the motor bracket (108) is in the forward position.

As shown in FIG. 6, two mounting holes (+30) are formed in front of the frames (90) and (92) on both sides of the carrier frame (86).

Those mounting holes (+30)...
132)...... to the front frame (1
34) is attached.

A leaf spring (13) is installed in front of the front frame (134).
The proximal end of 6) is attached. The leaf spring (136) is
As shown in FIG. 8, a thrust ball bearing (138) is attached to the tip. Ball bearing (138
), as shown in Fig. 1, the outer ring (11l-38a) is fixed to the leaf spring (136), and the ball (140
), and a wheel holder that passes through the center of the inner ring (138b), which is a movable ring, is fixed to the shaft (142). In the wheel holder, a contact plate (144) is integrally formed on the shaft (1, 42), and as shown in Fig. 1, the contact plate (144)
the type wheel (14) in the cassette case (12).
is urged backward, and the aforementioned crown surface (30) and crown gear (1
28) to ensure proper engagement.

In addition, both side mounting holes (14) of the front frame (134)
6) A card holder (150) is attached to (148) as shown in FIG.

Therefore, in the state shown in FIG. 5, the motor shaft (126) of the selection motor (64) is connected to the type wheel (1).
4), rotate the type wheel (14), select the desired type, and hit it with the printing hammer (70) to release it onto the paper (
74) can be printed.

From the printing state shown in FIG. 5, the type wheel (14)
When replacing the cassette holder (62), press the knob (
152), the cassette holder (62) is rotated backward about the support shaft (66) against the toggle spring (122), and the cassette holder (62) is suspended from the upper connecting shaft (104) of the cassette holder (62). Motor bracket (10
8) backwards and from the support shaft (66) to the crown surface (30
) and the distance from sabot 1 to shaft (66) to connection shaft (10
Depending on the lever ratio of the distance up to 4), the crown surface (30) and the crown gear (128) are disengaged, and conversely, as shown in
4) and the engaging pin (116) respectively through the circular arc hole (10
0), (1,02) and the rear of the long hole (118). Then, the cassette holder (62) falls backward around the support shaft (66), and the upper part of the cassette holder (62) falls toward the platen (
68), making it easier to replace the wheel cassette (10).

By the way, in the first embodiment described above, the case where the present invention was applied to a printer was explained. However, the present invention is not limited to printers, but can be similarly applied to typewriters and other printing devices.

Furthermore, in the embodiment described above, the wheel cassette (10) in which the type wheel (14) is housed in the cassette case (12) is detachably attached to the cassette holder (62). However, this invention uses a bare type wheel that is not stored in a cassette case.
Even in a printing device used in connection with a motor shaft, a thrust l-ball bearing may be similarly interposed between the leaf spring and the type wheel, and the type wheel may be biased by the leaf spring. .

Note that in order to eliminate friction between the type wheel and the leaf spring, an oil-impregnated bearing or a resin such as tetrafluoroethylene may be used instead of the thrust ball bearing (138).

Therefore, according to the present invention, since a thrust ball bearing is interposed between the leaf spring and the type wheel,
Even if there is some variation in the elastic force of the leaf spring, the selection motor and the type wheel can be reliably connected without causing any trouble. Friction is eliminated, the type wheel rotates smoothly, durability is improved, frictional noise is eliminated, noise is prevented, and the effects of temperature changes are eliminated.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of main parts showing the connection state between the type wheel and the selection motor in the serial impact printer shown in FIGS. 2 to 8. FIG. 2 to 8 show each part of a serial impact printer which is an embodiment of the present invention, FIGS. 2(A) and (B) are front and back views of a wheel cassette used in the printer, and FIG. is a cross-sectional view of the type wheel stored in the cassette,
Figure 4 is a sectional view of the cassette case that houses the type wheel, Figure 5 is a side view of the carriage, Figure 6 is an exploded view of it, and Figure 7 is a view of the carriage when the wheel cassette is removable. The side view, FIG. 8, is a plan view of the carriage shown in FIG. FIG. 9 is a sectional view showing a state in which a type wheel and a selection motor are connected in a conventional printing device. (14)・・・・・・・・・・・・Type wheel (20)・・・・・・・・・・・・・・・Type (64)
・・・・・・・・・・・・・・・Selection motor (
70)・・・・・・・・・・・・Print hammer (1
2fi)...Motor shaft (136)
・・・・・・・・・・・・Plate spring (+38)・・・・・・
...... Slus 1 - Ball bearing patent applicant Shunsuke Nakao Patent attorney Ricoh Co., Ltd. Figure 4

Claims (1)

[Claims] 1. A type wheel is urged by a leaf spring and connected to a selection motor, and the selection motor rotates the type wheel to sequentially select desired type, and the selected type is applied to a printing hammer. What is claimed is: 1. A daisy-serial printing device that sequentially prints by hitting the printing wheel, characterized in that a thrust ball bearing is interposed between the leaf spring and the printing wheel. 2. A thrust ball bearing is attached to the tip of a leaf spring, and a contact plate fixed to a movable ring of the ball bearing is pressed against a spring contact protrusion at the center of the type wheel to bias the type wheel. The daisyrial printing device according to item 1.