JPH0373375A - Printer - Google Patents

Abstract

PURPOSE:To make the rotation of a paper feeding roller accurate and stabilize the quality by a method wherein a pulse motor is operated further by several pulse steps in the rotational direction prevailing right before a gear shift, and after the pulse motor is returned in the opposite direction by the same number of pulse steps, the shifting of the gear is performed. CONSTITUTION:For the control of a printer when a paper feeding roller 1 is driven counter-clockwise, at the time when the rotation of a pulse motor 4 is switched from paper feeding to the movement of a carriage 16, the pulse motor 4 is further operated by several pulse steps in the rotational direction prevailing right before the gear shift, i.e., clockwise, and after the pulse motor 4 is returned counter-clockwise by the same number of pulse steps, power is interrupted from a solenoid 8, and a switching gear 7 is shifted. After making a clockwise return, which is generated due to the flection of a shaft part by the reaction force generated on the paper feeding roller, if the pulse motor 4 is returned to the normal driving position again, the backlash moves to the driving side of gear teeth by this motion, and a return, which is generated on a two-stage gear for reduction when the switching gear is disengaged, is made sufficiently small, and therefore, the engagement position at when it is engaged with the switching gear again does not slip, and the paper feeding roller is accurately driven.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a printer in which a single motor moves a carriage mounted with a printing device and moves paper.

(Prior Art) In recent years, printers have been used as output devices for computers and the like. Printers often use two motors each for paper feeding and carriage drive, but printers have been developed that use t motors for both purposes to reduce costs.

This conventional printer will be explained with reference to FIGS. 2 to 7.

FIG. 2 is a plan view showing the configuration of a conventional printer.

A paper feed roller 1 made of rubber or the like is rotatably held in a frame 3 by two bearings 2 fitted to its shaft portion 1a, and feeds the paper by sandwiching the paper between it and a support roller (not shown). conduct.

The pulse motor 4 drives a switching gear 7 rotatably and slidably attached to a guide shaft 6 fixed to the frame 3 via a pinion 5 attached to its rotating shaft 4a. The switching gear 7 is driven by a solenoid 8 fixed to the frame 3, and slides on the guide shaft 6.
One of two two-stage reduction gears 10 and 11 rotatably mounted on a fixed shaft 9 implanted in the frame 3.
The two two-stage reduction gears 10 and 11 that mesh with each other are connected to a stopper gear 1 fitted in the middle of the fixed lll1l19.
2 is braked by spring washers I3 on both sides of the switch, and the rotation is stopped at the same time as switching.

The two-stage deceleration gear 10 includes a timing pulley 1 rotatably fitted to the end of the shaft portion 1a on the paper feed roller.
The timing pulley 1 meshes with the gear part 14a integrated with the timing pulley 1.
A reciprocating carriage 16 drives a timing belt 15 wound around the timing belt 4, and is equipped with a printing device (not shown) fixed to the timing belt 15.
to drive. In addition, the above-mentioned timing belt 15 is
The equation II′0 conversion is carried out by the individual play Puliev,
The carriage 16 is slid between the driven pulley 18 in the same direction as the paper feed roller ↓.

On the other hand, the two-stage deceleration gear 11 meshes with the gear 19 fixed to the shaft portion 1a of the paper feed roller ↓, and the paper feed roller ↓
to drive.

The solenoid 8 drives the switching gear 7 via a drive rod 20, and the end of the drive rod 20 is supported with a degree of freedom by a tension coil spring 21 whose one end is fixed to the frame 3. When the solenoid 8 is de-energized, the switching gear 7 is engaged with the two-stage deceleration gear 10 that drives the carriage 16.

FIG. 4 is an enlarged perspective view of the main parts of the switching gear 7.
In order to facilitate the meshing of the two-stage reduction gears 10 and 11, chamfers 7a are provided at both ends of the teeth.

The operation of the printer configured as above will be explained.

In FIG. 2, when the solenoid 8 is de-energized, the switching gear 7 is engaged with the two-stage deceleration gear 10, and when the pulse motor 4 is operated, the rotation is caused by the pinion 5, the switching gear 7, and the two-stage deceleration gear 10. Stage gear 10, timing pulley 14.
The carriage 16 is driven by the timing belt 15.

Next, when the solenoid 8 is energized, the drive rod 20 is rotated clockwise, and as shown in FIG. 3, the switching gear 7 is disengaged from the two-stage deceleration gear 10.

When the pulse motor 4 is operated in this state, meshing with the two-stage deceleration gear 11 that drives the paper feed roller ↓, its rotation is sequentially transmitted to the pinion 5, the switching gear 7, the two-stage deceleration gear 11, and the gear 19. , the paper feed roller 1 rotates by a predetermined angle. After rotating the paper feed roller 1, when the solenoid 8 is de-energized, the switching gear 7 disengages from the two-stage deceleration gear 11 due to the tensile force of the tension coil spring 21, and returns to the deceleration mode shown in FIG. It returns to the meshing state with the second gear lO, and the power of the pulse motor 4 is transmitted to the carriage 16.

The friction load caused by the spring washer 13 is reduced by the switching gear 7
When one of stage gears 10 and 11 is engaged, rotational deviation of the other stage gear that is not engaged is prevented.

(9! A problem to be solved by Akira) Figs. 5 and 6 are side views of the gear train that drives the paper feed roller 1 shown in Fig. 3 @, as seen from the pulse motor 4 side. 5 shows a state in which the switching gear 7 is engaged, and FIG. 6 shows a state in which the solenoid 8 is de-energized.

Each figure shows a state in which the mesh is disengaged.

In FIG. 5, when the pinion 5 is rotated counterclockwise and the gear 19 of the paper feed roller 1 is driven clockwise and then stopped, the backlash of each gear and the v
XIIIT is biased in one direction.

Furthermore, when the paper feed roller 1 is made of rubber or the like and the paper to be fed is thick such as a postcard, the amount of deformation of the rubber is large, so the reaction force that the paper feed roller 1 receives during paper feeding is also large. From this state, when the switching gear 7 is switched to disengage the two-stage deceleration gear 11, the deflection of the shaft portion La of the paper feed roller l is restored, and the distance between the axes of the gear 19 and the two-stage deceleration gear 11 is becomes shorter, pushing the two-stage deceleration gear 11 back clockwise, and furthermore, due to the load between the gears, the play that had been created upward between the fixed shaft 9 and the two-stage deceleration gear 11 returns to its original position.

The clockwise movement of the teeth meshing with the switching gear 7 is increased. That is, as shown in FIG. 6, since the load is removed, the two-stage deceleration gear 11 tends to move clockwise from the tooth profile shown by the broken line to the tooth profile shown by the solid line.

7(a), 7(b) and 7(C) are side views of the meshing portion of the two-stage deceleration gear 11 and the switching gear 7, which are enlarged views of the states shown in FIGS. 5 and 6, respectively. It is a diagram.

In FIG. 7(a), the switching gear 7 rotates clockwise and becomes a two-stage deceleration gear! To drive tR +
A backlash occurs with ib. Next, when the switching gear 7 is disengaged, the two-stage deceleration gear 1
1 is pushed back clockwise, and the amount of return changes as shown in FIG. 7(b) or FIG. 7(c) depending on the thickness of the paper. In FIG. 7(b), when the switching gear 7 meshes again, the tooth 7a is in a position where it can mesh between the tooth 11a and 1t+b, but in FIG. 7(c), the tooth 7a is in a position where it can mesh between the tooth ttb and the tooth 11c. There was a problem in that the meshing deviated by one tooth, resulting in a discrepancy between the number of pulses of the pulse motor 4 and the movement of the paper feed roller Y. Note that since the braking force provided by the spring washer 13 is small, it takes more than one minute to suppress the movement of the two-stage deceleration gear 11 as described above; on the other hand, if sufficient braking force is applied, the load on the pulse motor 4 can be reduced. Increased and undesirable.

The present invention solves the above problems and provides a printer with stable quality in which the rotation of the paper feed roller is accurate.

(Means for Solving the Problems) In order to solve the above problems, the present invention moves the pulse motor in the rotational direction immediately before the gear change by a few more pulses, then returns it in the opposite direction by the same number of pulses, and then shifts the gear. This means making a switch.

(Function) With the above configuration, the clockwise return amount that occurs due to the deflection of the shaft due to the reaction force generated on the paper feed roller is fed, and then the paper is returned to the normal 1 drive position iti.

The backlash moves to the opening side of the teeth, and the return that occurs in the two-stage deceleration gear when the switching gear is disengaged is sufficiently reduced, so the meshing position of n and 'F, which mesh with the switching gear again, does not deviate, thus preventing the supply of Paper rollers are driven accurately.

(Example) An example of the present invention will be described with reference to FIGS. 1 and 2. The configuration of the printer according to the present invention is the same as the conventional example shown in FIG. 2, so a description thereof will be omitted.

FIG. 1 is a flowchart showing a control procedure for a printer according to the present invention, taking as an example the case where the paper feed roller 1 is driven counterclockwise. When switching the rotation of the pulse motor 4 from paper feeding to movement of the carriage 16, the pulse motor 4 is moved in the rotational direction immediately before the gear change, that is, clockwise, by an additional few pulses, and then counterclockwise by the same number of pulses. After returning the pulse 9, the solenoid 8 is de-energized and the switching gear 7 is switched.

(Effects of the Invention) As explained above, according to the present invention, the return angle of the two-stage deceleration gear at the time of gear switching due to the deflection of the paper feed roller shaft is driven by the backlash of the gear immediately before switching. Since it moves in the direction, it becomes sufficiently small and accurate engagement is possible when re-driving, resulting in a highly reliable printer.

[Brief explanation of drawings]

Fig. 4 is a flowchart showing the control during paper feeding in an embodiment of the present invention, Figs. 5 and 6 are side views of the gear train for driving the paper feed roller;
FIG. 3(c) is an enlarged side view of a main part showing the meshing state of the switching gear and the two-stage reduction gear. DESCRIPTION OF SYMBOLS 1... Paper feed roller, 1a... Shaft part, 2... Bearing, 3... Frame, 4... Pulse motor,
4a... Rotating shaft, 5... Pinion, (3.
・Shaft in the dormitory, 7... Switching gear, 8... Solenoid, 9... Fixed shaft, 10, 1.1... Two-stage deceleration gear, 12... Retaining ring, 13... Spring washer,
14...timing pulley, 14a...gear part,
15...timing belt, 16...reciprocating stand,
17... Idle pulley, 18... Driven pulley,
19...Gear. 20... Drive rod, 21... Tension coil spring.

Claims (1)

[Claims] A pulse motor, a reduction gear train for moving the carriage and feeding the paper, a switching gear for selectively transmitting power to the reduction gear train, and a drive source for switching the pulse motor. Before removing the switching gear from the reduction gear train for paper feeding using the above drive source, the pulse motor was rotated in the same direction for several pulses more than the predetermined number of pulses, and then turned back in the opposite direction for the same number of pulses. The printer is characterized in that the gears are switched afterward.