JPH0477281A - Paper feed apparatus and printer - Google Patents

Abstract

PURPOSE:To absorb the backlash between gears by forming an elastic part to the frame of a main body and supporting the transmission gear positioned in the drive system of a platen roller by the elastic part. CONSTITUTION:An intermediate gear 21 is mounted so as to forcibly elastically deform the elastic part 14a of the side plate 14 of a frame 14 in the direction shown by an arrow A1 to be meshed with a platen gear 18 and a motor gear 20. Therefore, the diameter of the intermediate gear 21 is set to a size sufficient to elastically deform the elastic part 14a in the direction shown by an arrow A1. The elastically deformed elastic part 14a energizes the intermediate gear so as to press the same to the platen gear 18 and the motor gear 20 by the elastic restoring force in the direction shown by an arrow A2. By this constitution, the backlash between the gears 20, 21 in the drive system of a platen roller 11 is absorbed and the paper feed due to the platen roller becomes accurate and the recording position of a recording head 22 to printing paper 17 can be set with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device built into a printer such as a typewriter, and a printer incorporating the paper feeding device.

[Prior Art] The paper feeding device incorporated in Blink uses printing paper (
A widely used method includes a platen roller around which recording paper is wound, and a paper feed motor rotates the platen roller to feed the printing paper.

The drive system of the platen roller in such a paper feeding device consists of a motor gear (driving gear) attached to the output shaft of the paper feeding motor, a platen gear (driven gear) attached to the rotating shaft of the platen roller, and these motor gears and the platen gear. It consisted of an intermediate gear (transmission gear) that meshed with the

By the way, backlash between the motor gear, the intermediate gear, and the platen gear causes a slight misalignment in the rotational operations of the paper feed motor and the platen roller. This deviation causes a loss of accuracy in the amount of paper feed, and is particularly noticeable when performing reverse indexing in which the printing paper is fed in the opposite direction to the insertion direction.

Therefore, in order to absorb the backlash between the gears in the drive system of the platen roller, conventional measures have been taken such as making the intermediate gear a double gear structure or pressing the intermediate gear against the motor gear and platen gear with a spring. .

Figures 3 and 4 are examples of the former measure, in which the intermediate gear 3 that meshes between the motor gear 1 and the platen gear 2 has a double gear structure in which two gears 3a and 3b are stacked on the same axis. ing. The gears 3a and 3b are biased by a torsion coil spring (not shown) so that the teeth of the gears deviate from each other, and due to the circumferential deviation of the teeth, the gap between the gears is reduced as shown in FIG. (
It is designed to absorb backlash.

FIG. 5 is an example of the latter measure, in which an intermediate gear 3 is attached to a bracket 5 rotatably supported around a shaft 4, and a spring 6 biases the bracket 4 in the direction of the arrow in the figure. It has become. As a result, the intermediate gear 3 is pressed against the motor gear 1 and the platen gear 2, causing backlash.

[Problems to be Solved by the Invention] As described above, conventionally, in order to absorb the backlash between gears in the drive system of the platen roller, the intermediate gear 3 has a double gear structure, the bracket 5 and the spring 6 required. Therefore, there were problems in that the number of parts increased, making assembly troublesome and increasing costs.

An object of the present invention is to provide a paper feeding device that can eliminate the above-mentioned conventional problems and absorb backlash between gears in a drive system of a platen roller with a simple structure that does not require a large number of parts. The purpose of the present invention is to provide a printer equipped with the following functions.

[Means for Solving the Problems] In order to achieve the above object, the paper feeding device of the present invention has the following features:
A frame of a main body of the paper feed device, a platen roller supported by the frame to feed recording paper, a paper feed motor attached to the frame, and a platen roller connected to the output shaft of the paper feed motor and located on the frame. drive gear;
a driven gear connected to the rotating shaft of the platen roller and located on the frame; an elastic part formed on the frame and having elasticity; and a driven gear supported by the elastic part and connected to the drive gear and the driven gear. It is characterized by having a transmission gear meshing therebetween.

Further, the printer of the present invention includes a frame of a main body of a paper feeding device, a platen roller supported by the frame and feeding the recording paper, a paper feeding motor attached to the frame, and connected to an output shaft of the paper feeding motor. a driving gear connected to the rotating shaft of the platen roller and located on the frame, an elastic piece formed on the frame and having elasticity, and supported by the elastic piece. The apparatus is characterized in that it has a transmission gear that meshes between the driving gear and the driven gear, and a recording means that records on recording paper fed by the platen roller.

[Function] This invention forms an elastic part in the frame of the main body of the paper feeding device, and supports the transmission gear located in the drive system of the platen roller on this elastic part. The backlash between gears is absorbed by using the elastic force of

In addition, an increase in the number of parts can be prevented by using a simple configuration in which the support part of the transmission gear is an elastic part formed in the frame of the main body of the paper feeding device.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 11 is a platen roller, and bearings 12 at both ends thereof are attached to left and right side plates 14 and 15 forming a frame 13 of the main body of the paper feeding device. As a result, the platen roller 11 is rotatably supported between the side plates 4 and 15, and is driven to rotate, thereby winding the printing paper (recording paper) 17 inserted between the platen roller 11 and the paper pan 16. to feed the paper.

A platen gear (driven gear) 18 is attached to the end of the rotating shaft of the platen roller 11 on the side plate 14 side. Further, a paper feed motor 19 is attached to the side plate 14, and a motor gear (drive gear) 20 is attached to its output shaft. Further, a platen gear 18 is provided on the side plate 14.
and an intermediate gear (transmission gear) 2 that meshes with the motor gear 20.
1 is rotatably supported, and a portion of the side plate 14 that supports the intermediate gear 21 is an elastic portion 14a having elasticity. As shown in FIG. 2, the elastic portion 14a is integrally formed so as to extend from the side plate 14, and its base end forms a constricted portion 14b that is easily bent.

Here, the side plate 14 in this embodiment is molded from plastic, and the elastic part 14a is movable by the elasticity of the fin part 14b at its base end.

Paper feeding devices configured in this manner are incorporated into printers equipped with various types of recording heads. In this example, the recording head (recording means) 22 of the printer is a full-line type ink jet recording head having a length corresponding to the maximum recording width for the printing paper 17.

Next, the effect will be explained.

The intermediate gear 21 is attached so as to forcibly elastically deform the elastic portion 14a of the side plate 14 in the force direction indicated by the arrow A in FIG. 2, and meshes with the platen gear 18 and the motor gear 20. Therefore, the diameter of the intermediate gear 21 is large enough to elastically deform the elastic portion 14a in the direction of arrow A1. The elastic portion 14a that has been elastically deformed moves the intermediate gear 21 to the platen gear 1 by elastic restoring force in the direction of arrow A2.
8 and the motor gear 20.

As a result, the backlash between the gears in the drive system of the platen roller 11 is absorbed, the paper feeding by the platen roller 11 becomes accurate, and the recording position of the recording head 22 with respect to the printing paper 17 is determined with high precision. become.

Note that the shape of the elastic portion 14a is arbitrary, as long as it can support the intermediate gear 21 and has elasticity.

[Effects of the Invention] As explained above, in the present invention, an elastic portion is formed in the frame of the main body of the paper feeding device, and the transmission gear located in the drive system of the platen roller is supported on this elastic portion. Because of this configuration, backlash between the gears can be absorbed using the elastic force of the elastic portion.

Moreover, since the support part of the transmission gear is a simple structure in which the support part is an elastic part formed in the frame of the main body of the paper feeding device, the number of parts does not increase.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of essential parts showing one embodiment of the present invention, Fig. 2 is a front view of the platen roller drive system shown in Fig. 1, and Fig. 3 is a front view showing a conventional example of the platen roller drive system. FIG. 4 is an enlarged view of the inside of FIG. 3, and FIG. 5 is a front view showing another conventional example of a platen roller drive system. DESCRIPTION OF SYMBOLS 11... Platen roller, 12... Bearing, 13... Frame, 14, 15... Side plate, 14a... Elastic part, 14b... Neck part, 16... Paper pan, 17. ...Print paper (recording paper), 18...Platen gear (driven gear), 19...Paper feed motor, 20...Motor gear (drive gear), 21...Intermediate gear (transmission gear), 22. ... Recording head (recording means). Diagram

Claims (1)

[Scope of Claims] 1) A frame of a main body of a paper feeding device, a platen roller supported by the frame and feeding the recording paper, a paper feeding motor attached to the frame, and connected to an output shaft of the paper feeding motor. a driving gear connected to the rotating shaft of the platen roller and located on the frame; an elastic part formed on the frame and having elasticity; supported by the elastic part. A paper feeding device comprising: a transmission gear that meshes between the drive gear and the driven gear. 2) a frame of the paper feed device main body; a platen roller supported by the frame to feed recording paper; a paper feed motor attached to the frame; and a platen roller connected to the output shaft of the paper feed motor and mounted on the frame. a driven gear connected to the rotating shaft of the platen roller and located on the frame; an elastic piece formed on the frame and having elasticity; supported by the elastic piece, the drive gear A printer comprising: a transmission gear meshing with the driven gear; and a recording means for recording on recording paper fed by the platen roller.