JP2792031B2 - Printer paper feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a paper feeder for a printer.

[Conventional technology]

2. Description of the Related Art Conventionally, in a paper feeder of a printer, power is transmitted to a friction roller or a drive shaft of a tractor by using a single pulse motor as a power source and reducing the speed by a gear.

[Problems to be solved by the invention]

However, in such a conventional paper feed device, the paper feed amount per one step of the pulse motor, that is, the paper feed resolution is
Generally set to 1/216 ", 1/300", or 1/360 ", in order to enable these two at the same time.
If a fine resolution is set, such as 1/1080 "or 1/1800", the same paper feed speed cannot be obtained unless the drive frequency of the pulse motor is increased accordingly. However, if the printer is set to the fine resolution, there is a disadvantage that the paper feeding speed is reduced.

Therefore, an object of the present invention is to provide a paper feeding device that does not reduce the paper feeding speed even if the paper feeding resolution of a printer is set to be small in order to solve such a conventional problem.

Also, in the conventional paper feeder, even if the paper feed resolution is set to a very small value and the pulse motor is driven in divided units, since the gears are used in the power transmission system, the influence of backlash between the gears is affected. However, there is a disadvantage that the set feed amount is not sufficient.

Another object of the present invention is that even if the paper feed resolution of the printer is set to be very small, an error in the set fine paper feed amount due to backlash in the power transmission mechanism between the motor and the paper feed medium such as a friction roller or tractor. An object of the present invention is to provide a paper feeding device that realizes no feeding.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a printer of the type in which a pulse motor is used to drive a sheet conveying means so as to provide a fine resolution. A driving force transmitting means having a speed reducing means, and an intermediate motor provided in the intermediate speed reducing means for applying a rotational force required for the sheet conveying means, wherein the intermediate motor is simultaneously synchronized with the pulse motor. It is formed so as to be driven.

And as a specific example, the driving force transmission means is formed of a series of gears meshing with each other, the intermediate reduction gear is formed of one of the gears, and the intermediate motor is formed of a gear forming the intermediate reduction gear. It is characterized by being arranged coaxially.

Further, as another example, the driving force transmitting means uses a toothed timing belt and a plurality of pulleys for bridging the timing belt, and the intermediate motor is coupled to one of the plurality of pulleys via a clutch. It is characterized by the following.

[Action]

According to the present invention, the intermediate motor having the above function is simultaneously driven in synchronization with the pulse motor. Accordingly, while the paper feed is positioned at a minute resolution by the driving of the pulse motor, the paper conveying means can be driven by a necessary rotational force by the simultaneous driving of the intermediate motor. That is, even if the paper feed amount per step of the pulse motor is set to be very small and the motor is driven at a speed higher than the maximum response frequency of the pulse motor, the intermediate motor at the position reduced through the intermediate reduction gear Are driven synchronously with low rotation and high torque, thereby achieving high-speed paper feed.

Also, by using a toothed timing belt without play in the transmission system without using gears for the speed reduction and power transmission mechanism, play in the transmission system can be completely removed.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First
FIG. 2 is a plan view of the embodiment of FIG. 1, and FIG. 2 is a side view mainly showing a gear train. The pulse motor 1 which is a power source for paper feed and performs positioning has a pulse motor pinion 5 fixed to its shaft by press-fitting or screw tightening, and similarly press-fitted to an intermediate motor shaft 12 of an intermediate motor 11 fixed to a frame 13. Alternatively, it is connected to a large gear of the intermediate reduction gear 4 fixed by screwing. The intermediate gear 4 has a two-stage structure in which a large gear and a small gear are integrally formed. The small gear is engaged with the friction roller gear 3 fastened to a rotatable friction roller shaft 10 supported by a frame 13, and simultaneously formed on the frame 13. It also meshes with a tractor transmission gear 6 connected to a tractor gear 7 fastened to a supported and rotatable tractor drive shaft 8. A cylindrical friction roller 2 made of rubber or a material similar thereto is attached to the friction roller shaft 10.
The tractor drive shaft 8 is a round bar having two split grooves as shown in FIG. 2, and is inserted into the drive end of the tractor 9. The tractor 9 is held by a tractor holding shaft 14 fixed to a frame 13 and the tractor drive shaft 8 so as to be movable left and right as shown in FIG.

In this embodiment, a pulse motor 1 which is a driving source of the paper feed and is used for positioning the paper, and a friction roller 2 and a tractor 9 which are a paper feeding medium are arranged in a wheel train arrangement which is greatly reduced via an intermediate reduction gear 4. When the pulse motor 1 is driven, the friction roller gear 3 is driven through the intermediate reduction gear 4.
, And branches into two wheel train paths that rotate the tractor gear 6 via the tractor transmission gear 6, and drives the friction roller 2 and the tractor 9, respectively. At this time, the intermediate motor 11 arranged coaxially with the intermediate reduction gear 4 is slower and synchronized with the drive frequency of the pulse motor 1 by the reduction ratio of the pulse motor pinion 5 and the large gear of the intermediate reduction gear 4. Drive. As described above, the two motors connected with a specific reduction ratio are simultaneously driven in synchronization with each other, so that the positioning of the pulse motor 1 can be performed with the fine resolution by the pulse motor 1 of the deceleration source and the maximum speed of the pulse motor 1 can be determined by the intermediate motor 11 of the deceleration destination. Even in a high-speed region exceeding the response frequency, the motor can be driven slower by the reduction ratio, so that a high torque can be provided, and the friction roller 2 and the tractor 9 as the paper feed medium can be driven at a high speed.

3 and 4 show an embodiment according to claim (2).
FIG. 4 is a plan view, and FIG. 4 is a side view mainly showing a drive transmission system. Here, instead of the gear used in the previous embodiment,
A toothed timing belt and a pulley that meshes with the timing belt are used. A pulse motor pulley 25 is fixed to the shaft of the pulse motor 1 at the deceleration source by press-fitting or screwing. The intermediate motor 11 is fixed to the frame 13,
One end of an electromagnetic clutch 28 is fixed to the drive end. At the other end of the electromagnetic clutch 28, an intermediate reduction pulley 24 having two stages, large and small, is fixed, and the large pulley is connected to the pulse motor pulley 25 by a timing belt A29.
Connected to 2 additional small pulleys for the intermediate deceleration pulley 24
One is connected to the friction roller pulley 23 via a timing belt B30, and the other is connected to the tractor pulley 27 via a timing belt C31. The transmission route to that point is the same as in the previous embodiment.

In this embodiment, since the intermediate motor 11 is connected to the intermediate deceleration pulley 24 via the electromagnetic clutch 28, the electromagnetic clutch is disengaged at the time of minute paper feeding, which is several times the paper feeding resolution, and only the pulse motor 1 is driven. When a large amount of paper is fed, the two clutch motors are synchronized and driven by providing the reduction ratio given by the pulse pulley 25 and the large pulley of the intermediate reduction pulley 24, as in the previous embodiment, by connecting the electromagnetic clutch 28. As described above, since the power transmission system is entirely composed of the timing belt and the pulley, there is no backlash in the power transmission system, and a high-precision paper feed with no error with respect to the set feed amount even in the case of the minute feed is realized. Also, by using the electromagnetic clutch 28 at the time of stopping or feeding of minute paper, the intermediate motor can be used.
It is possible to eliminate a decrease in position accuracy due to 11 detents.

〔The invention's effect〕

As described above, a paper feeder of a printer according to the present invention is a printer of the type that drives a sheet conveying unit using a pulse motor to impart a minute resolution, between the pulse motor and the sheet conveying unit. A driving force transmitting means provided with an intermediate decelerating means, and an intermediate motor provided in the intermediate decelerating means for applying a rotating force required for the sheet conveying means, wherein the intermediate motor is a pulse motor It is formed so as to be driven simultaneously in synchronism with. As a more specific example, the driving force transmitting means includes a series of gears meshing with each other, the intermediate speed reducing means includes one of the gears, and the intermediate motor includes a gear that forms the intermediate speed reducing means. It is characterized by being arranged coaxially.

Accordingly, while the paper feed is positioned at a minute resolution by the driving of the pulse motor, the paper conveying means can be driven by a necessary rotational force by the simultaneous driving of the intermediate motor. That is, even if the reduction ratio between the pulse motor and the friction roller or the tractor is set to be large and the paper feed amount per one step of the pulse motor is set to be very small, the intermediate motor provided coaxially with the intermediate gear, Since it is driven at low rotation and high torque, it has the effect of enabling high-speed paper feeding exceeding the maximum response frequency of the pulse motor.

Also, by using a toothed timing belt for the power transmission system for the paper feeder of such a printer,
This has the effect of eliminating backlash in the power transmission system and realizing high-precision paper feeding without error with respect to the set paper feeding amount even at the time of fine paper feeding.

[Brief description of the drawings]

FIG. 1 is a plan view of a paper feeder of a printer showing a first embodiment, and FIG. 2 is a side view mainly showing the train wheel. FIG. 3 is a plan view of a paper feeder of a printer showing a second embodiment, and FIG. 4 is a side view showing a power transmission system thereof. 1 pulse motor 2 friction roller 3 friction roller gear 4 intermediate reduction gear 5 pulse motor pinion 7 tractor gear 8 tractor drive shaft 9 tractor 10 friction roller shaft 11 …… Intermediate motor 29, 30, 31 …… Timing belt

Claims (3)

(57) [Claims] 1. A printer of the type in which a sheet conveying means is driven by using a pulse motor in order to provide a minute resolution, wherein a driving force interposed between the pulse motor and the sheet conveying means and provided with an intermediate speed reducing means. A transmission means, and an intermediate motor provided in the intermediate deceleration means for applying a necessary rotational force to the paper conveying means, wherein the intermediate motor is formed so as to be simultaneously driven in synchronization with the pulse motor. A paper feeder for a printer. 2. The driving force transmission means comprises a series of gears meshing with each other, the intermediate reduction means comprises one of the gears, and the intermediate motor is disposed coaxially with the gear forming the intermediate reduction means. The paper feeder for a printer according to claim 1, wherein the paper feeder is provided. 3. The method according to claim 2, wherein the driving force transmitting means uses a toothed timing belt and a plurality of pulleys for bridging the timing belt, and the intermediate motor is coupled to one of the plurality of pulleys via a clutch. The paper feed device for a printer according to claim 1, wherein