JPH02277675A - Gear mechanism of printer - Google Patents

Abstract

PURPOSE:To actuate a printer with a smaller actuating torque than the maximum load thereof by dividing a driving gear into a driving gear shaft and a driving gear, arranging said driving gear shaft and driving gear to be alternately rotatable with a predetermined angle, and interposing a driving gear spring having a specific spring force between said driving gear shaft and driving gear. CONSTITUTION:A driving gear shaft 3 is fixed to a motor shaft 2, and a driving gear 4 is secured to the driving gear shaft 3 to be rotatable with a predetermined angle. The spring force of a driving gear spring 5 is set to be larger than the cogging torque of a motor 1 and smaller than the average torque of a printer. The driving gear spring 5 urges the driving gear shaft to the driving gear in a direction reverse to a rotating direction of the motor 1. When the power supply is cut as the motor is stopped with the maximum load, the driving gear shaft 3 and motor shaft 2 are rotated by the driving gear spring 5 in a direction A reverse to the rotating direction B of the motor 1 until they are brought in touch with a shaft engaging part 3b and a gear engaging part 4b. Thereafter, when a voltage is applied, the motor shaft 2 and driving gear shaft 3 are started to be powerfully rotated. As a result, a driving protrusion 3a collides against a receiving part 4a which receives the driving force, and this colliding energy and the actuating torque of the motor function as the force when the printer is actuated again.

Description

[Detailed description of the invention] [Industrial application field] The present invention mainly relates to a small printer installed in a calculator or the like.

[Prior Art] Most conventional technologies of this type have a structure in which the motor shaft and the drive gear are directly connected.

[Problems to be Solved by the Invention] However, with the above-mentioned conventional technology, even if the printer stops during a process with a large load due to a drop in power supply voltage or a sudden power off while the printer is operating, it is not possible to restart the printer within the specified voltage range. In order to achieve this, the load on the motor was reduced by increasing the reduction ratio, and the motor's speed was increased accordingly, or the output of the motor itself was increased by increasing the size of the motor or using a high-efficiency motor. Therefore, when the motor rotation speed increases, noise is generated, radio wave noise increases, and efficiency decreases, leading to an increase in current value.A large motor becomes an obstacle to downsizing, and a high-efficiency motor increases cost. there were.

The present invention was made in order to solve these drawbacks, and by making it possible to start the printer with a motor with a starting torque smaller than the maximum load of the printer, it achieves low power consumption due to low speed rotation, low noise, and compact size. The purpose is to provide a gear mechanism for printers that realizes high efficiency and low cost.

Means for Solving the Problem] A gear mechanism for a printer of the present invention includes a motor that rotates in one direction to drive the printer, a drive gear shaft fixed to a motor shaft of the motor, and the drive gear shaft. A drive gear is pivotably mounted on a shaft for rotation at a certain angle, and a spring force is set to a spring force that is greater than the cogging torque of the motor and smaller than the average torque of the printer, and the drive gear shaft is set to a spring force that is greater than the cogging torque of the motor and smaller than the average torque of the printer. a drive gear spring that biases the motor; a drive protrusion provided on the drive gear shaft that transmits driving force when the motor is driven; and a drive force receiver provided on the drive gear that comes into contact with the drive protrusion. a shaft locking portion provided on the drive gear shaft for locking the drive gear and the drive gear shaft at a position rotated by a certain angle by the spring force of the drive gear spring when the motor is stopped; It is characterized by comprising a shaft locking portion and a gear locking portion provided on the driving gear that comes into contact with the shaft locking portion.

[Function] According to the above configuration of the present invention, if the printer stops at the maximum load stroke for some reason during the printing process and the power is turned off, the drive gear spring causes the drive gear shaft and the motor shaft to stop driving the motor. When the motor shaft and drive gear shaft stop at a position rotated by a certain angle in the opposite direction of rotation, and then a voltage within the specification range is applied, the motor shaft and drive gear shaft begin to rotate around a fixed angle vigorously, and the drive protrusion of the drive gear shaft and The drive force receiver of the drive gear collides with each other, and this collision energy and the starting torque of the motor become the force for restarting, so the printer can be started with a starting torque smaller than the maximum load of the printer.

[Examples] Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing the structure of an embodiment of the gear mechanism of a printer according to the present invention when the motor is driven, and FIG. 2 is a plan view when the motor is driven.

1 is the motor and 2 is the motor shaft. Reference numeral 3 denotes a drive gear shaft which is fixed to the motor shaft 2 by press fitting or the like. Reference numeral 4 denotes a drive gear which is rotatably attached to the drive gear shaft 3 at a fixed angle. 3a is a drive protrusion, and 3b is a shaft locking part, which are formed on the drive gear shaft 3. 4a is a driving force receiving part, and 4b is a gear locking part, which are formed on the driving gear 4. The driving force receiving portion 4a and the gear locking portion 4b are formed to sandwich the driving protrusion 3a and the shaft locking portion 3b such that they can rotate at a certain angle. Reference numeral 5 designates a drive gear spring, with one spring arm 5a having a shaft portion 3e formed on the drive gear shaft 3 as an axis, a spring hook formed on the drive gear shaft 3 is hooked on a spring hook portion 3d, and the other arm is attached to a spring hook portion 3d. A spring hook 5b formed on the drive gear 4 is hung on a portion 4d. The spring force of the drive gear spring 5 is set to be larger than the cogging torque of the motor 1 and smaller than the average torque of the printer between the rotation angle C of the drive gear 4 and the drive gear shaft 3.

Arrow B indicates the direction of motor rotation, and arrow A in the opposite direction indicates the direction in which the drive gear spring 5 biases the drive gear shaft 3 against the drive gear 4. The driven gear 6 meshes with the drive gear 4 to transmit the power of the motor, thereby operating the printer.

Since a load is applied to the driving gear 4, the driving protrusion 3a and the driving force receiving portion 4a are in contact with each other.

A collar 3c formed on the outer circumference of the drive gear shaft 3 is sandwiched between a collar 4C formed on the inner circumference of the drive gear 4.

FIG. 3 is a plan view after the motor drive signal is turned off.

When the drive signal of the motor 1 is turned off, the drive gear spring 5 applied to the drive gear shaft 3 and the drive gear 4 is biased, and the drive protrusion 3a rotates in the direction A, and the drive force receiver separates from the drive gear spring 5. This shows a state in which the shaft locking portion 3b and the gear locking portion 4b are in contact with each other.

In this embodiment, if the printer stops at the maximum load stroke for some reason during the printing process and the power is turned off, the drive gear shaft 3 and motor shaft 2 are connected to the motor 1 by the drive gear spring 5.
The shaft locking portion 3b and the gear locking portion 4b rotate in the direction A, which is opposite to the driving rotation direction B, until the shaft locking portion 3b and the gear locking portion 4b come into contact with each other. After that, when a voltage within the specification range is applied, the motor shaft 2 and drive gear shaft 3
begins to rotate vigorously, the driving protrusion 3a and the driving force receiving portion 4a collide, and this collision energy and the starting torque of the motor act as a force at the time of restarting.

[Effects of the Invention] As described above, according to the present invention, the drive gear that was directly fixed to the motor shaft is divided into two parts, the drive gear shaft and the drive gear, and the drive gear is attached to the drive gear shaft, The drive gear and the drive gear shaft are structured so that the drive gear and the drive gear shaft can be rotated by a certain angle by the drive protrusion and shaft locking portion provided on the drive gear shaft, the drive force receiving portion and the gear locking portion provided on the drive gear, Furthermore, the drive gear shaft is biased in the opposite rotation direction of the motor relative to the drive gear using a drive gear spring with a spring force greater than the cogging torque of the motor and less than the printer's average torque, allowing the printer to start from a stroke with a large load. When this happens, the motor will be able to start with less torque than its load. As a result, the reduction ratio can be reduced, allowing the motor to rotate at a lower speed, increasing efficiency, resulting in lower power consumption and lower noise.Furthermore, since a smaller motor can be used, a smaller printer can be obtained at lower cost. As described above, the effects of the present invention are extremely large.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the structure of an embodiment of the gear mechanism of a printer according to the present invention when the motor is driven. Figure 2 is a plan view when the motor is driven. FIG. 3 is a plan view after the motor drive signal is turned off. 1... Motor 2... Motor shaft 9... Drive gear shaft a b C de 4 ・ 4 a ・ 4 b ・ 4 C ・ 4 d ・ 5 ・ 5 ・ 5 a ・ 5 b ・ 6 ・ Driving protrusion Part shaft locking part flange spring hook is part shaft part driving gear driving force receiver is part gear locking part flange spring hook is part driving gear spring arm arm driven gear a Applicant Seiko Epson Co., Ltd. Agent Patent attorney Yoshi Suzuki Sanbe and 1 other person

Claims (1)

[Claims] a motor that rotates in one direction to drive the printer; a drive gear shaft fixed to the motor shaft of the motor; a drive gear rotatably attached to the drive gear shaft by a fixed angle; a drive gear spring that is set to a spring force that is greater than the cogging torque and smaller than the average torque of the printer and biases the drive gear shaft in the opposite rotational direction of the motor with respect to the drive gear; and a drive gear spring that transmits driving force when the motor is driven. A driving protrusion provided on the driving gear shaft; a driving force receiving part provided on the driving gear that comes into contact with the driving protrusion; and a spring force of the driving gear spring when the motor is stopped. A shaft locking portion provided on the drive gear shaft for locking the drive gear shaft at a position rotated by a certain angle, and a gear locking portion provided on the drive gear that comes into contact with the shaft locking portion. A printer gear mechanism characterized by: