JPH0789181A - Printer - Google Patents

Abstract

PURPOSE:To print without generation of trouble even when thickness of a paper varies by changing a position of a print head unit with respect to a paper feed unit such that a print head deviates from a convey passage at moving in one direction more than at moving in other direction. CONSTITUTION:On the outer side of an upper base plate 12 on the left side adjacent to a driven pulley 23, a ring row 26 constituting a head position changing means 25 is provided. When a print head 15 moves to the right and is in a state ready for printing, an arm 29 is rotated counterclockwise so as to release connection of a transmission gear 30 and the ring row 26, and an upper block of a printer is allowed by gravity to be on a lower block covering it. When the print head 15 moves to the left so as to return to a home position, the transmission gear 30 is engaged with the ring row 26 by the clockwise rotation of the arm 29, a slide plate 27 is slid to the right through a rack 27b by torque transmitted to the ring row 26, and the slide plate 27 is pushed up along a slant face of a slanted member, so that the print head 15 is allowed to deviate from a paper convey passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer in which a distance between a print head and a sheet can be adjusted according to a change in sheet thickness.

[0002]

2. Description of the Related Art Among various printers, a flat platen is used as a printer used for recording in a bankbook, a head surface of a print head is opposed at a predetermined interval, and paper is supplied between the two to print. There are some that are designed to do. Generally, the distance between the platen and the head surface (head gap) is constant.

[0003]

As in the prior art, when the head gap is always constant,
When the paper thickness of the paper to be printed changes, the distance between the paper surface and the head surface also differs, resulting in different printing strength. Also, if the paper thickness is larger than the head gap, or if the paper thickness changes at line feed such as when there is a step difference like a deposit / savings passbook, the print head cannot cross the step, Further, when the continuous paper is used, the head surface may be caught in the perforation of the continuous paper, which may cause a print failure such as a paper jam.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printer which does not cause printing trouble even if the paper thickness of the paper changes.

[0005]

In order to achieve the above-mentioned object, a printer according to the present invention comprises a paper feed unit which constitutes a paper feed path, and a paper feed direction at a position where a print head faces the paper feed path. A print head unit that is supported so as to be able to reciprocate in the orthogonal direction and is displaceable with respect to the paper feeding unit so that the print head is separated from the transport path, and when the print head moves in one direction. It is characterized in that it is provided with a head position changing means for displacing the print head unit with respect to the paper feeding unit so that the print head is separated from the transport path as compared with the case where the print head is moved in the other direction.

The above-mentioned head position changing means is provided with a train wheel for displacing the print head unit with respect to the paper feeding unit, and a transmission gear wheel for transmitting the driving force of the drive means for moving the print head to the train wheel. There is.

Further, the head position changing means includes a lock member for locking the print head unit and the paper feeding unit at different positions when the print head moves in the other direction by changing the moving position of the print head in one direction. It is provided.

[0008]

The head position changing means copes with the change in the paper thickness by displacing the print head unit so as to move away from the transport path when moving in one direction than when moving in the other direction.

The head position changing means operates the train wheel for displacing the print head unit only when the print head unit moves in one direction through the transmission gear of the driving force of the driving means for driving the print head. .

Further, the head position changing means locks the print head unit and the paper feeding unit at different positions when the print head moves in the other direction by the lock member, so that the thickness of the paper during the printing operation is increased. Can be changed when

[0011]

An embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 2 and 3, the printer in this embodiment is composed of a lower block P and an upper block Q.

As shown in FIGS. 1 to 3, the lower block P is
A platen 3 bridged between a pair of base plates 1 and 2 facing each other, and paper guides 4 provided before and after the platen 3.
5 and a paper feed unit 6 that constitutes a conveyance path including the above-mentioned paper guide. The paper feed unit 6 is composed of a line feed motor 7 fixed inside the left base plate 1, a line feed train 8 and a pair of paper feed shafts 9 and 9 supported between opposing base plates. There is. A plurality of paper feed rollers 10, ... Are provided on each of the paper feed shafts 9, 9 so as to be integrally rotatable.

The upper block Q is attached to upper base plates 12 and 13 which are swingably supported at one end of both base plates 1 and 2 via support shafts 11 and 11. Upper base plate 12 on both sides,
A print head unit 14 is provided between the printheads 13.

As shown in FIG. 1, the print head unit 1
The print heads 15 that form part 4 of the upper base plate 1 face each other.
The carrier 18 is mounted on a carrier 18 that reciprocates along two guide shafts 16 and 17 that are bridged between 2 and 13. A ribbon cassette 19 is attached to the print head 15. The head surface of the print head 15 is attached downward, and the ribbon mask 15a is attached to the head surface (see FIG. 3).

A carrier motor 21 which is a driving means for moving the print head 15 via a motor plate 20 is provided on the right upper base plate 13. A gear 2 provided so as to be able to mesh with a pinion 21a fixed to the drive shaft of the motor 21.
2a is provided with a drive pulley 22 which is integrally rotatable.

A driven pulley 23 corresponding to this pulley is provided at a portion of the left upper base plate 12 facing the position of the drive pulley 22 of the right upper base plate 13. Both pulleys 22,
A belt 24 is stretched between 23. One specific portion of the belt 24 is connected to the carrier 18, and the rotation of the carrier motor 21 causes the carrier 1 to rotate via the belt 24.
8, that is, the print head 15 mounted thereon can be reciprocated.

The left upper base plate 1 adjacent to the driven pulley 23
On the outer side of 2, there is provided a train wheel 26 that constitutes the head position changing means 25. The operation of the head position changing means 25 is as follows.
The first step is to rotate the train wheel 26 transmitted via the belt 24 from the drive pulley 22 which is the drive means for moving the print head 15. Then, in the second stage, the rotation transmitted to the train wheel 26 is transmitted to the slide plate 27 slidably provided on the left upper base plate 12, and the inclined surface 27a formed on the slide plate 27 causes the upper surface to move upward. By lifting one side of the block Q around the support shaft 11 against gravity, the print head unit 14 is displaced with respect to the paper feed unit 6 so that the print head 15 moves away from the paper transport path.

As shown in FIG. 2, the inclined surface 27a of the slide plate 27 is formed downward, and this inclined surface is formed at the upper end of the inclined member 28 supported by the left base plate 1. The slope 28a is in contact. Slide plate 2
When 7 is moved to the right, one side of the upper block Q is lifted around the support shaft 11 against gravity so that the print head 15 is separated from the sheet conveyance path by the inclined surface 27a.
When the slide plate moves to the left, the upper block returns to its original position by the action of gravity.

The slide plate 27 is slidably supported by a guide 27d fixed to the upper base plate 12. To move the slide plate 27 to the right, a rack 27b (see FIGS. 4 and 5) formed on the side surface of the slide plate is engaged with a pinion 26a forming a train wheel, and the train wheel 26 is rotated. Done.

As shown in FIG. 1, the train wheel 26 is driven by utilizing the rotation of a carrier motor 21 which is a driving means for moving the print head 15. The transmission mechanism that transmits the rotation of the carrier motor 21 to the train wheel 26 is a driven pulley 23.
Arm 29 that engages the support shaft 23a of the vehicle with a predetermined frictional force
And a transmission gear 30 rotatably supported at its tip. The transmission gear 30 can be attached to and detached from the first gear 26b of the train wheel 26 by swinging the arm 29. That is, when the carrier 18 is in the return stroke (moving to the left), the arm 29 is rotationally moved in the clockwise direction and both gears mesh with each other, and when the carrier is in the printing stroke (moving to the right), the arm is in the counterclockwise direction. It is a mechanism that moves and disengages both gears.

As shown in FIGS. 2 and 5, below the vicinity of the rear end of the slide plate 27, the print head 15 is moved in one direction by changing the moving position of the print head 15 in the other direction. A lock member 31 for locking the unit 14 and the paper feed unit 6 at different positions is provided. The lock member 31 is provided with a stopper 31a at one position on the disk-shaped rotating body.
And is rotatably supported by the upper base plate 12. The stopper 31a is biased by a tension spring 32 so that it always faces upward (see FIG. 8).

In addition to the above, in the upper block Q, as shown in FIG. 3, at a position corresponding to the paper feed rollers 10 and 10, a plurality of paper pressers rotatably supported by support shafts 33 and 33 are supported. Rollers 34 ... Are provided.

Next, the operation of this embodiment will be described. In the state shown in FIGS. 1 to 4, the sheet (not shown) is placed on the sheet conveying path.
When is inserted, the paper is fed between the print head 15 and the platen 3 by the paper feeding unit 6, and the printing operation is performed there. The print operation of the print head 15 is performed only when moving to the right, and is not performed when moving to the left.

As shown in FIG. 1, when the print head 15 moves to the right to perform the printing operation, the arm 29 rotates counterclockwise and the transmission gear 30 and the train wheel 26 are disconnected. Is in a closed state (see Fig. 4). Therefore, since the rotational force of the carrier motor 21 is not transmitted to the train wheel 26, the slide plate 27 does not slide, and the upper block Q is in a state of being covered on the lower block P by the action of gravity.

Next, when the print head 15 moves leftward and returns to the home position, as shown in FIG.
Rotates clockwise, and the transmission gear 30 meshes with the first gear 26b of the train wheel 26 to rotate the train wheel 26. Therefore, the slide plate slides to the right through the rack 27b formed on the side surface of the slide plate 27 by the pinion 26a which is the final gear of the train wheel 26.

As shown in FIG. 7, the slide plate 27 slides and is pushed up by the slope along the slope 28a of the inclined member 28, and one side of the upper block Q supporting the slide plate resists gravity. It is pushed up around the spindle 11. As a result, the print head unit 14 is displaced with respect to the paper feed unit 6 so that the print head 15 is separated from the paper conveyance path, and the distance (head gap) between the head surface and the platen 3 is increased. Even if the paper thickness becomes thick during the line feed operation performed, it is possible to easily overcome this. In this way, a line feed is made, and when moving to the printing operation of the next line, the arm 29 is again used.
Rotates counterclockwise, and the transmission gear 30 and the train wheel 26 are disconnected. Therefore, the restraint of the slide plate 27 is released, and the slide plate retreats due to the gravitational action of the upper block Q to return the print head 15 to the original position and return to the printable state.

The operation of the lock member 31 will be described with reference to FIG. FIG. 8A shows the print head 15
Slide plate 27 and tilting member 2 in a state in which
8 shows the positional relationship between the lock member 31 and the lock member 31. Since the slide plate 27 is retracted, the tip end of the slope portion 27a is in contact with the slope 28a of the slope member 28. For this reason,
The stopper 31a of the lock member is also accommodated in the recess formed on the lower surface of the slide plate 27 and is in the normal position.

Next, when the print head 15 reaches a portion where the paper thickness changes, such as a step of the paper during printing in the forward stroke, the print head 15 returns by a predetermined amount and stops at a position slightly before the home position. . At this time, as shown in FIG. 6, the arm 29 rotationally moves in the clockwise direction, the transmission gear 30 meshes with the gear 26b of the first stage of the train wheel, and the transmission gear 30 moves this via the rack 27b of the slide plate 27. In order to move the slide plate 27 forward, the slide plate 27 is pushed up by the positional relationship between the inclined surface portion 27a and the inclined portion 28a of the inclined member 28, as shown in FIG. 8B. Therefore, as shown in FIG. 7, one side of the upper block Q supporting the upper block Q is pushed up around the support shaft 11 against gravity, and the print head 15 is separated from the transport path. As the slide plate 27 advances, the stopper 31a of the lock member 31 rotates clockwise in accordance with this, but the tip end portion is pressed against the lower surface of the slide 27 plate by the tension spring 32.

Further, when the slide plate 27 advances, as shown in FIG. 8C, the stopper 31 of the lock member 31.
a engages with the engaging portion 27c near the rear end of the slide plate 27. Here, the movement of the print head 15 is stopped, and in this state, the print head 15 moves to the right to move the transmission gear 3
Even if the 0 and the train wheel 26 are disconnected from each other, the slide plate 27 cannot be retracted by the lock member 31, and the distance between the print head 15 and the platen 3 can be increased when the print head 15 is moved to the right. As a result, the print head 15 can be moved to the right, and printing can be performed on the thick side of the paper with the step of the paper as the boundary.

In the normal return path, as shown in FIG. 3D, the slide plate 27 can be further advanced to push itself up and increase the head gap. At this time, the stopper 31a of the lock member 31 is
It is located behind the slide plate 27.

Then, when the print head 15 enters the forward stroke, the transmission gear 30 and the gear train 26 shown in FIG. 7 are disconnected, the constraint of the slide plate 27 is released, and the upper block Q is retracted by its own weight. , The state shown in FIG. 7E is restored to the state shown in FIG.

In this embodiment, the slide plate 27 is provided with a single engaging portion 27c, but the slide plate 27 is provided with a plurality of engaging portions 27c, and the locking member 31 is selectively attached to these engaging portions 27c. Of the print head 15 by engaging the stopper 31a of
The distance between the print head 15 and the platen 3 when moving to the right may be increased in multiple steps. In this case, there are a plurality of parts such as steps where the paper thickness changes in the moving direction of the print head 15. It is possible to print on some paper without any inconvenience.

Further, in this embodiment, a combination of the slide plate and the inclined member is adopted as the head position changing means, but the invention is not limited to this combination,
For example, a ball screw may be used instead of the slide plate to move up and down the upper base plate, and other means may be adopted.

[0034]

According to the present invention, since the head position changing means of the print head is provided, even if the paper thickness of the paper changes, it is possible to easily get over this and to prevent obstacles such as paper jams. The printing operation can be continued without causing it.

Further, if the driving force of the moving means of the print head is used as the driving source of the head position changing means, a driving source for that purpose is not required, so that the structure can be simplified.

If the head position changing means is provided with a lock member, the print head unit and the paper feed unit are locked with the print head retracted even if the paper thickness of the paper changes during printing. As a result, printing can be performed without any trouble due to changes in paper thickness.

[Brief description of drawings]

FIG. 1 is a plan view of the present invention.

FIG. 2 is a left side view of FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is an enlarged plan view of a head position changing unit.

FIG. 5 is an enlarged side view of the same.

FIG. 6 is a plan view showing a state in which the print head is moving to the left.

FIG. 7 is a left side view illustrating a state in which the print head is separated from the sheet conveyance path.

FIG. 8 is an operation explanatory view of a head position changing unit and a lock member.

[Explanation of symbols]

 6 Paper Feed Unit 14 Print Head Unit 15 Print Head 21 Drive Means 25 Head Position Changing Means 26 Wheel Train 30 Transmission Gear 31 Lock Member

Claims (3)

[Claims] 1. A paper feed unit that constitutes a paper transport path, and a print head that is reciprocally supported at a position facing the transport path in a direction orthogonal to the paper transport direction, and the print head is A print head unit that is displaceable with respect to the paper feed unit so as to be separated from the transport path; and when the print head moves in one direction, the print head moves in the other direction. A printer comprising: a head position changing unit that displaces the print head unit with respect to the paper feeding unit so as to be separated from the transport path. 2. The head position changing means according to claim 1, wherein a train wheel for displacing the print head unit with respect to the paper feeding unit and a driving force of a driving means for moving the print head are provided on the wheel. A printer, comprising: a transmission gear that transmits to a row. 3. The head position changing means according to claim 1, wherein the print head unit and the paper are moved when the print head moves in the other direction by changing the moving position of the print head in one direction. A printer having a lock member for locking the feed unit at a different position.