JP2981119B2 - Paper feeder for printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for printing equipment.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, a driven gear 50 which rotates together with a paper feed roller is intermittently driven by a driving gear (not shown) connected to a paper feed motor to feed the paper. In the paper feeder,
In order to maintain the paper feed pitch accurately, the driven gear 5
A detent gear 51 which rotates together with the detent gear 51 is provided. A detent arm 53 having a claw 52 meshed with the detent gear 51 is moved by a spring 54 to the detent gear 5.
When the paper feed roller is rotated in the paper feed direction (clockwise) together with the driven gear 50 by being urged toward the first side and rotatably provided by the support shaft 55, the state shown in FIG. As shown, when the detent arm 53 is retracted from the detent gear 51 by the exciting action of the electromagnetic coil 56 against the urging force of the spring 54, the sheet feed motor is stopped, and the driven gear 50 is stopped together with the sheet feed roller. As shown in FIG. 9A, the energization of the electromagnetic coil 56 is interrupted, the detent arm 53 is returned by the urging force of the spring 54, and the claw 52 is meshed with the detent gear 51, so that the driven gear 50 and the paper feed roller There is one in which the and are stopped at a fixed position.

[0003]

As shown in FIG. 8, when the detent arm 53 is attracted from the detent gear 51 by the electromagnetic coil 56, noise is generated because the detent arm 53 collides with the suction surface of the electromagnetic coil 56. I do. In addition, the collision may cause the detent arm 53 to rebound and collide with the detent gear 51, which also causes noise.

[0004]

According to the first aspect of the present invention,
A detent gear that is driven by a paper feed motor and rotates together with the paper feed unit is provided, and a detent arm urged toward the detent gear by an urging member and meshed with the detent gear is provided so as to be able to advance and retreat with respect to the detent gear, A predetermined air gap that exerts a suction force on the detent arm at a position where the detent arm is most separated from the detent gear by a component force generated by a contact force between the teeth of the detent gear rotating in the paper feed direction and the detent arm. This is a paper feeder of a printing apparatus provided with an electromagnetic coil having a suction surface positioned at a position facing the open state.

According to a second aspect of the present invention, there is provided a detent gear which is driven by a paper feed motor and rotates together with the paper feed unit, and a detent arm which is urged toward the detent gear by an urging member and meshed with the detent gear. The detent gear is provided so as to be able to advance and retreat with respect to the detent gear, and the detent arm is deflected from the detent gear against the urging force of the urging member by a component force generated from the contact force between the teeth of the detent gear rotating in the paper feeding direction and the detent arm. A motor drive that applies a low-speed pulse to the paper feed motor at the beginning of the start of paper feed and applies a high-speed pulse to the paper feed motor during a period after the detent gear pushes and separates the detent arm. The means is a paper feeder of a printing device.

[0006]

According to the first aspect of the present invention, when paper is fed,
The paper feed unit is rotated together with the detent gear. At this time, the detent arm is separated from the detent gear by the component force generated by the contact force between the teeth of the detent gear and the detent arm, and the detent is moved at the position where the separation distance reaches the maximum. Since the suction surface of the electromagnetic coil opposes by opening a predetermined air gap that exerts a suction force on the arm, when the detent arm is pushed away from the detent gear by rotation of the detent gear in the paper feed direction, the detent arm sucks the electromagnetic coil. There is no collision with the surface. In addition, since the electromagnetic coil is limited to an attraction force that attracts the detent arm from a position where the detent arm is separated from the detent gear by the maximum distance, even when the electromagnetic coil is excited, the detent arm is kept at the suction surface of the electromagnetic coil. No collision.

According to a second aspect of the present invention, similarly to the first aspect of the invention, at the time of feeding a sheet, the detent arm is separated from the detent gear by a component force generated by the contact force between the teeth of the detent gear and the detent arm. At the beginning of the paper feeding, a low-speed pulse is applied to the paper feeding motor, so that the energy for pushing the detent arm away from the detent gear can be reduced. The collision of the detent arm can be prevented. After the detent arm is separated from the detent gear, a high-speed pulse is applied to the paper feed motor to feed the paper at a high speed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. A paper feed unit 3 is provided in which a plurality of rollers 1 are fixed to a shaft 2 at intervals, and one end of the shaft 2 has a driven gear 4 and a number of teeth 5 inclined in one direction.
Is fixed. A circular boss 7 is formed at the center of one side surface of the detent gear 6, and a slip spring 8 having an inner diameter slightly smaller than its outer diameter is press-fitted into the outer periphery of the boss 7. Hooks 9 and 10 that bend laterally are formed at both ends of the slip spring 8.

As shown in FIG. 3, a stamp base 11 having a plurality of grooves 11a into which the rollers 1 are inserted is provided. A detent arm 14 having a claw 13 meshed with the teeth 5 of the detent gear 6 is held on a support plate 12 for fixing the stamp base 11 via a support shaft 15 so as to be vertically rotatable. The detent arm 14 is urged toward the detent gear 6 by a spring 17 which is an urging member fixed to a pin 16 protruding from the side surface.

As shown in FIG. 1, a paper press 18 for pressing a paper on the printing stand 11 is urged in one direction by a spring 19 and is rotatably held by a support shaft 20. A printing head 21 for an ink jet printer is provided on the printing stand 11.
Are facing each other. Further, a paper feed motor 22 that can rotate forward and reverse is fixedly provided.
The transmission gears 24 and 25 which receive the rotational force from the pinion 23 directly connected to the gears are held so as to rotate in the same manner about the support shaft 26, and the driving force which transmits the rotational force of the transmission gear 25 to the driven gear 4 is received. A gear 27 is provided. Then, the paper feed direction of the paper feed motor 22 (counterclockwise)
Is transmitted to the driven gear 4, and a one-way clutch 28 that disconnects the paper feeding motor 22 and the driven gear 4 when the paper feeding motor 22 rotates in the clockwise direction is built in the transmission gear 25.

A coil spring 29 is fixed between the hook 9 of the slip spring 8 and a fixed portion (not shown) located above the hook 9. Further, the support plate 12 has a projection 3 that interferes with the rotation locus of the hook 9.
0 and an electromagnetic coil 31 are provided.

By setting the teeth 5 of the detent gear 6 to be inclined in one direction like a ratchet, the teeth 5 of the detent gear 6 and the teeth 5 of the detent gear 6 are rotated when the driven gear 4 is rotated clockwise during sheet feeding. The detent arm 14 is separated from the detent gear 6 by a component force generated from the contact force of the arm 14 with the claw 13,
The suction surface 31a of the electromagnetic coil 31 is arranged at a position facing the detent arm 14 with a predetermined air gap opened when the detent arm 14 is most separated from the detent gear 6. The magnetic force generated by the electromagnetic coil 31 is set to a value that attracts the detent arm 14 with a minimum force against the urging force of the spring 17.

In the present embodiment, the pulse applied to the paper feed motor 22 is set at approximately 1200 PPS. Accordingly, the energy that causes the detent arm 14 to separate from the detent gear 6 due to the component force generated by the contact force between the teeth 5 of the detent gear 6 and the claw 13 of the detent arm 14 is determined by the claw 13
Are slightly lifted from the teeth 5 of the second member.

In such a configuration, the detent arm 14 is urged by the spring 17 to mesh with the detent gear 6. When the paper feed motor 22 is driven in the paper feed direction (counterclockwise) with a step number (rotation angle) corresponding to the paper feed pitch slightly larger than the paper feed pitch, the transmission gear 24,
The drive gear 27 is rotated by the one-way clutch 28 for 25 rotations.
Thus, the driven gear 4 is driven clockwise together with the detent gear 6 and the roller 1. At this time, since the detent gear 6 rotates clockwise, the detent arm 14 resists the urging force of the spring 17 due to the component force generated by the contact force between the teeth 5 of the detent gear 6 and the claw 13 of the detent arm 14. 6 and the electromagnetic coil 31 is excited immediately after this separating operation, so that the detent arm 14
Is kept away from The sheet is conveyed in this state.

During the feeding of the sheet, the slip spring 8 tightened by the boss 7 of the detent gear 6 while the detent gear 6 is being fed clockwise causes the driven gear 4 and the detent gear 6 to extend while the coil spring 29 is extended downward. However, the slip spring 8 slips with respect to the rotating detent gear 6 after the hook 9 comes into contact with the upper part of the projection 30 and is kept stationary.

At this time, the energy stored in the coil spring 29 by the extension operation is transferred to the slip spring 8.
When the paper feed motor 22 is stopped, the detent gear 6 is urged in the counterclockwise direction. Accordingly, when the power supply to the electromagnetic coil 31 is cut off and the detent arm 14 is returned upward by the urging force of the spring 17, and the paper feed motor 22 is driven in the opposite direction (clockwise) to the paper feed direction, the one-way clutch 28 Since the connection between the motor 22 and the driven gear 4 is cut off, the detent gear 6 rotates counterclockwise at a rotation speed lower than the rotation speed of the paper feed motor 22 by the urging force of the coil spring 29. In this case, when the detent gear 6 rotates in the paper feed direction (clockwise) before that,
Since the hook 9 of the slip spring 8 is positioned at a fixed position by the projection 30 and the amount of deflection of the coil spring 29 is constant, there is no shortage of force for returning the detent gear 6 counterclockwise, and the paper feed motor 22 is rotated in the reverse direction. Then, the detent gear 6 can be returned to a fixed position where the detent gear 6 is securely engaged with the claw 13 of the detent arm 14.

Accordingly, by slightly driving the roller 1 in the sheet feeding direction and then returning the roller 1 by the urging force of the coil spring 29, the rotation angle of the roller 1 can be fixed and the sheet feeding pitch can be fixed. . Even if the urging force of the spring 17 for urging the detent arm 14 is reduced, the spring can be reliably engaged with the detent gear 6, so that the capacity of the paper feed motor 22 can be reduced, and the detent arm 14 and the detent gear 6 Can be prevented from being worn.

Further, the biasing force of the coil spring 29 for returning the detent gear 6 can be reduced because the amount of bending is fixed, and the slip spring 8 stores a large torsion torque in consideration of a margin. Therefore, the torque of the paper feed motor 22 can be reduced, and the wear of the boss 7 by the slip spring 8 can be suppressed. In this embodiment, hooks 9 and 1 are provided at both ends of the slip spring 8.
By bending the boss 7, both ends of the slip spring 8 in contact with the boss 7 can be made smooth, and the slip operation of the slip spring 8 with respect to the boss 7 of the detent gear 6 can be made smooth. Wear can be more effectively prevented. Further, since the diameter of the slip spring 8 can be increased by sandwiching the hooks 9 and 10 from both sides, assembly to the boss 7 is easy.

The same purpose can be achieved by urging the hook 10 of the slip spring 8 downward by the coil spring 29.

As described above, the detent arm 14 is separated from the detent gear 6 by the component force generated by the contact force between the teeth 5 of the detent gear 6 and the claw 13 of the detent arm 14, but the separation distance has reached the maximum. At this position, a predetermined air gap that exerts a suction force on the detent arm 14 is opened, and the suction surface 31a of the electromagnetic coil 31 is opposed to the detent arm 14, so that the rotation of the detent gear 6 in the paper feeding direction causes the detent arm 14 to protrude from the detent gear 6. When released, the detent arm 14 is
Does not collide with the suction surface 31a. Further, since the electromagnetic coil 31 is limited to an attraction force enough to attract the detent arm 14 from a position where the detent arm 14 is separated from the detent gear 6 by the maximum distance, the detent arm 14 is also excited when the electromagnetic coil 31 is excited. Does not collide with the suction surface 31a of the electromagnetic coil 31. Thereby, it is possible to suppress the generation of noise due to the collision between the detent arm 14 and the suction surface 31a of the electromagnetic coil 31.

Incidentally, the detent gear 6 in the sheet feeding is used.
The distance by which the detent arm 14 is pushed and separated by the detent gear 6 increases in proportion to the rotation speed of the motor, but the electromagnetic coil 31 may be arranged at a position where the detent arm 14 does not reach the suction surface 31a with the pushing force. In the present embodiment, since the detent gear 6 is driven by the low-speed pulse, even if the suction surface 31a is brought close to the detent arm 14 in a state of meshing with the detent gear 6, the detent arm 6 cannot be moved by the pushing force of the detent gear 6. 14 does not collide with the suction surface 31a.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 5, an interface 33 connected to a CPU 32, a host computer (not shown), a ROM 34 storing fixed data such as programs, and a RAM temporarily storing variable data.
35, head driving means 3 for driving the print head 21
6. A paper feed motor drive means 37 for driving the paper feed motor 22 and a carriage motor drive means 39 for driving a carriage motor 38 for moving a carriage (not shown) on which the print head 21 is mounted are connected. .

When the paper feed motor 22 is rotated at the time of paper feed, if the energy for pushing the detent arm 14 away from the detent gear 6 is large, the detent arm 14 collides with the suction surface 31a of the electromagnetic coil 31 to generate a large noise. 7, the paper feed motor 22 is driven by a low-speed pulse (about 1200 PPS), as shown in FIG. However, even after the detent arm 14 is pushed away from the detent gear 6, it is driven by the low-speed pulse, so that the paper feeding speed is reduced.

On the other hand, the paper feed motor driving means 37 of the present invention applies a low-speed pulse (about 1200 PPS) to the paper feed motor 22 at the beginning of the start of paper feed, and the detent gear 6
Is applied to the paper feed motor 22 in a period after the sheet is separated.

In such a configuration, when a paper feed signal is received from the host computer, it is caused by the contact force between the teeth 5 of the detent gear 6 and the claws 13 of the detent arm 14, as in the first aspect of the present invention. The detent arm 14 is separated from the detent gear 6 by a component force and is attracted by the electromagnetic coil 31, but as shown in FIG.
At the beginning of the start of sheet feeding, a low-speed pulse (about 1200 PP) is sent from the sheet feeding motor driving means 37 to the sheet feeding motor 22.
By applying S), the energy for pushing the detent arm 14 away from the detent gear 6 can be reduced. Thereby, the suction surface 31 of the electromagnetic coil 31
The collision of the detent arm 14 with a can be prevented.

The elapsed time from the start of the paper feed motor 22 is counted by a counter (not shown), and the count value is set to a predetermined constant value (a value sufficient to separate the detent arm from the detent gear). Is reached, the paper feed motor driving means 37 applies a high-speed pulse (approximately 1800 PPS) to the paper feed motor 22.
This makes it possible to increase the paper feed speed.

In the above embodiment, the detent arm 1
4 is pushed away from the day tent gear 6, and the electromagnetic coil 3
1 has been described, but the detent arm 14
From the state in which the electromagnetic coil 31
May be excited. In this state, the detent arm 1
Since the gap between the coil 4 and the suction surface 31 a of the electromagnetic coil 31 is large, the suction force of the electromagnetic coil 31 does not reach the detent arm 14. However, when the electromagnetic coil 31 is excited from the state in which the detent arm 14 meshes with the detent gear 6, the timing for exciting the electromagnetic coil 31 can be given a margin.

[0028]

According to the first aspect of the present invention, when feeding a sheet, the sheet feeding section is rotated together with the detent gear, and at this time, the detent arm is rotated by a component force generated from the contact force between the teeth of the detent gear and the detent arm. The detent gear is separated from the detent gear, but the detent arm does not collide with the suction surface of the electromagnetic coil even if the separation distance reaches the maximum, and the electromagnetic coil is detented from the position where the detent arm is separated from the detent gear by the maximum distance. Since the attraction force is limited to the degree that the arm is attracted, the detent arm does not collide with the attraction surface of the electromagnetic coil even when the electromagnetic coil is excited. Noise can be suppressed by the collision of Yl power can be saved by using a.

According to the second aspect of the present invention, similarly to the first aspect of the invention, when the sheet is fed, the detent arm is separated from the detent gear by a component force generated from the contact force between the teeth of the detent gear and the detent arm. Then, at the beginning of the paper feed start, a low-speed pulse is applied to the paper feed motor,
The energy that pushes the detent arm away from the detent gear can be reduced, thereby preventing the detent arm from colliding with the suction surface of the electromagnetic coil and suppressing the generation of noise. After being separated from the gear, a high-speed pulse can be applied to the paper feed motor to increase the paper feed speed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of the invention described in claim 1.

FIG. 2 is a side view showing a meshed state between a detent gear and a detent arm.

FIG. 3 is an exploded perspective view showing a support structure for a detent arm and a slip spring.

FIG. 4 is an exploded perspective view showing a support structure of the slip spring.

FIG. 5 is a block diagram of an electronic circuit according to an embodiment of the present invention.

FIG. 6 is a graph showing a relationship between a change of a drive pulse to a motor and time.

FIG. 7 is a graph showing a relationship between a change of a driving pulse to a conventional motor and time.

FIG. 8 is a front view showing a conventional detent structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed motor 3 paper feed section 5 teeth 6 detent gear 14 detent arm 17 biasing means 22 paper feed motor 31 electromagnetic coil 31 a suction surface 37 paper feed motor drive means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-18370 (JP, A) JP-A-59-215884 (JP, A) Fully open 58-110455 (JP, U) Really open 180831 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 19/78 B41J 19/92

Claims (2)

(57) [Claims] A detent gear which is driven by a paper feed motor and rotates together with the paper feed portion; and a biasing member biases the detent gear to the detent gear side to move a detent arm meshed with the detent gear with respect to the detent gear. The detent arm is provided so as to be movable forward and backward, and exerts a suction force on the detent arm at a position where the detent arm is most separated from the detent gear by a component force generated by an abutting force between the teeth of the detent gear and the detent arm rotating in the sheet feeding direction. A paper feeder for printing equipment, comprising: an electromagnetic coil having a suction surface positioned at a position facing the air gap with a predetermined air gap opened. 2. A detent gear, which is driven by a paper feed motor and rotates together with a paper feed portion, is urged toward the detent gear by an urging member, and a detent arm meshed with the detent gear is moved relative to the detent gear. An electromagnetic coil provided so as to be able to advance and retreat, and attracting the detent arm from the detent gear against the urging force of the urging member by a component force generated by the contact force between the teeth of the detent gear and the detent arm rotating in the paper feed direction. A motor driving unit that applies a low-speed pulse to the paper feed motor in the initial stage of starting the paper feed, and applies a high-speed pulse to the paper feed motor in a period after the detent gear pushes and separates the detent arm. Characteristic paper feeder for printing equipment.