JPH028909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a typewriter having both a friction feed means and a tractor feed means.

Conventional Structure and Problems Conventionally, paper feeding in typewriters has been mainly achieved by friction feed using a platen and rollers.

However, in recent years, with the demand for higher printing speeds and larger amounts of printing, it has become necessary to install tractor feeds that use continuous paper. In general, most of the positioning mechanisms necessary for paper feeding in typewriters are ratchet mechanisms. In this ratchet mechanism, a gear is provided on the platen shaft, and a contact member having a tension function, such as a spring, is engaged with the teeth of the gear, thereby improving the positioning accuracy of the platen.

Now, most of the time when a tractor feed is attached to a typewriter, it is used for its role as a normal printer, and there is no need for a correction function, and there is no need to provide a positioning mechanism closely related to the correction function, that is, the ratchet mechanism mentioned above. It was thought that there was no such thing. This is because when using a tractor feed typewriter with a ratchet mechanism, the following two problems arise.

The first problem is noise.The sound of the teeth of the ratchet and the contactor engaging is very loud, which becomes a problem especially when continuous printing is performed.

The second problem is an increase in the motor load, and when the load torque when the ratchet teeth and the contactor engage is multiplied by the load specific to the tractor feed, the motor load increases, causing unstable paper feeding.

In addition, when attaching a tractor feeder to a conventional typewriter, a gear is additionally provided to transmit the driving force of the attached tractor feeder.
Tractor feeders were equipped with motors for power.

Problems to be Solved by the Invention However, if a typewriter is provided with a gear for driving the tractor feeder, the number of parts will increase accordingly, and if a dedicated motor is provided on the tractor feeder side, it will be difficult to control this motor. In order to supply power, it was necessary to connect a cable to the typewriter itself.

Means for Solving the Problems In order to solve the problems, the present invention provides a ratchet pawl that comes into contact with a gear that rotates as the platen rotates, and a drive gear of the tractor feeder that contacts the gear when the tractor feeder is mounted. The present invention includes a positioning member for positioning the tractor feeder that engages with the tractor feeder, and a member that is pressed by the tractor feeder when the tractor feeder is attached to separate the ratchet pawl from the gear.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a typewriter in one embodiment of the present invention.

In FIG. 1, 1 is a typewriter body. Reference numeral 2 denotes a tractor unit for feeding continuous paper, and is configured to be detachable from the typewriter main body 1 via a mounting plate 3. 4 is a platen rotationally driven by a motor (not shown);
It is supported by a platen shaft 5. Reference numeral 6 denotes a ratchet gear coaxially fitted to the platen shaft 5. Reference numeral 7 denotes a ratchet lever, which performs circular arc movement around a ratchet lever shaft 8. Reference numeral 9 denotes a contact, which engages with the ratchet gear 6 as shown in FIG. A spring 10 biases the ratchet lever 7 so that the contact 9 meshes with the ratchet gear 6.

Next, the configuration of the friction feed will be explained.

FIG. 3 shows a side view of the main part that performs friction feed.

In FIG. 3, 11 is a rotatably supported roller in contact with the platen 4, 12 is a paper guide plate that supports the roller 11, and 13 has a bail lever gear 13a in part, and is freely rotatable by a shaft 13b. A bail lever 14 is pivotally supported by a pinion that meshes with a bail lever gear 13a.
Reference numeral 15 denotes a shaft connected to the pinion 14, which has a half-moon portion 15a in part, and which is connected to the pinion 14.
Rotates in sync with 4. Note that 16 is a leaf spring that applies an urging force to the paper guide plate 12 so that the roller 11 comes into pressure contact with the platen 4, and 17 is a printing paper.

In the above configuration, the friction feed of the paper 17 will be explained below.

First, when the platen 4 is rotated in the direction of arrow D by a motor (not shown), the paper 17 is sent out in the direction of arrow B by the friction of the platen 4 and roller 11, which are in pressure contact with each other. In the state shown in FIG. 3, the half-moon portion 15a of the shaft 15 does not prevent the leaf spring 16 from pressing the paper guiding plate 12 against the platen 4. Therefore, the spring force of the leaf spring 16 maintains the pressing force of the roller 12 against the surface of the platen 4 at a predetermined level. Further, since the contactor 9 is engaged with and pressed against the tooth surface of the ratchet gear 6, the platen 4 can be accurately positioned without shifting in the rotational direction.

Next, the tractor field will be explained with reference to FIGS. 4, 5, and 6.

FIG. 4 shows the inside of the tractor 18 shown in FIG.

In Fig. 4, 19 is a tractor drive shaft;
20 is a sprocket gear rotated by the driving force of the tractor drive shaft 19. 21 is a belt wound around the sprocket gear 20 and the sprocket 20a, 22 is a protrusion provided on the surface of the belt 21, and 23 is a lid.

Further, FIG. 5 shows the inside of the interlocking section 24 of FIG. 1.

In FIG. 5, 25 is a timing pulley rotated by the tractor drive shaft 19, 26 is a belt having a protrusion 27 wound around the timing pulley 25 and the timing pulley 25a, and 28 is provided coaxially with the timing pulley 25a. The gear 29 is an intermediate gear that transmits the rotation of the gear 28 to the ratchet gear 6.

In the above configuration, the tractor 18 is driven by utilizing the rotation of the platen shaft 5, and the intermediate gear 2 is driven by the ratchet gear 6 coaxially with the platen shaft 5.
9, is transmitted to gear 28 and timing pulley 25a, is transmitted via belt 26 and timing pulley 25, from tractor drive shaft 19 coaxially connected to sprocket gear 20, and drives belt 21. There is a protrusion 22 on the belt 21.
are provided at regular intervals, which engage with feed holes (not shown) provided on the left and right sides of the paper 17,
Paper 17 is sent. Now, when the platen 4 rotates in the direction of the arrow E shown in FIG. 4, the paper 17 is sent in the direction of the arrow C, from the tractor 18, around the platen 4, and again to the tractor 18. In this case, the tractor 18 is the main source of driving force for feeding the paper. If a difference occurs between the circumferential speed of the belt 26 of the tractor 18 and the circumferential speed of the platen 4, normal paper feeding cannot be performed. Therefore, when installing the tractor unit 2, the friction feed device must be released. Therefore, by first moving the bail lever 24 in the direction of arrow F shown in FIG. 4, the half-moon portion 15a of the shaft 15 stands up, and the leaf spring 16 is pushed down in the opposite direction to the direction in which the platen 4 is located. The paper guiding plate 12 and roller 11 are separated from the platen 4 due to their own weight. Therefore, friction feed by the roller 11 and platen 4 cannot be performed.

The release of the ratchet mechanism will be explained below. As shown in FIG. 6, the tractor unit 2 is attached to the typewriter body 1 by engaging the mounting plate 3 of the tractor unit 2 with the platen shaft 5. That is, when the tractor unit 2 is mounted, the tip of the mounting plate 3 pushes down the ratchet lever 7, the contactor 9 is disengaged from the ratchet gear 6, and the ratchet mechanism is released.

Effects of the Invention As described above, the present invention has the following effects by configuring the ratchet means to be released when the removable tractor feed means is attached. .

(1) Since the ratchet means is released at the same time as the tractor feed means is installed, there is no need to provide a new mechanism for releasing the ratchet means, and since the ratchet means can be easily attached and detached, it is easy to attach the tractor. .

(2) The noise caused between the ratchet gear and its contacts becomes loud when tractor feed is used, that is, when continuous printing is the main purpose. However, by releasing the ratchet means it is possible to keep the noise low.

(3) The increase in the load torque caused between the ratchet gear and the ratchet gear contact may result in an excessive load torque on the motor when the tractor feed means is installed, considering its own load torque; This may cause unstable paper feeding. However, by releasing the ratchet means, the motor load torque can be significantly reduced.

(4) Since the driving force of the tractor feeder is transmitted from the ratchet gear provided on the typewriter body, there is no need to provide a separate gear on the typewriter side for transmitting the driving force of the tractor feeder.

[Brief explanation of drawings]

Figure 1 is a perspective view of a typewriter according to an embodiment of the present invention, Figure 2 is a side view of the ratchet mechanism of the typewriter, and Figures 3 and 4 are main points of the friction feed mechanism of the typewriter. FIG. 5 is a side view of a main part of the interlocking part of the same typewriter, and FIG. 6 is a side view of the ratchet mechanism of the same typewriter. 1... Typewriter body, 2... Tractor unit, 4... Platen, 6... Ratchet gear,
7... Ratchet lever, 9... Contact, 11...
... Roller, 12 ... Paper guide plate, 13 ... Bail lever, 14 ... Pinion, 18 ... Tractor, 24 ... Interlocking part.

Claims (1)

[Scope of Claims] 1. A typewriter with a detachable tractor feeder, comprising: a gear that rotates as the platen rotates; a ratchet pawl that comes into contact with the gear; a positioning member that positions the tractor feeder so that the drive gear of the tractor meshes with the gear; and a member that is pressed by the tractor feeder when the tractor feeder is attached to separate the ratchet pawl from the gear. A typewriter characterized by: