JP3360381B2 - Printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument, a medical instrument,
The present invention relates to a small printing device used for an OS terminal, a telephone terminal, and the like.

[0002]

2. Description of the Related Art With the spread of printing apparatuses in various industrial fields, not only demands for downsizing and price reduction of printing apparatuses, but also demands for high printing quality are increasing.

[0003] In the field of thermal printers, there is a strong market need for lower prices. Therefore, cost reduction by reducing the number of parts and assembling man-hours, and the diversification of use environments are required.
The need for low noise and multi-functionality is increasing. On the other hand, in terms of print quality, the need for printing not only characters but also graphics and graphs that can be drawn has increased, and paper drawing accuracy has been required more than ever to draw accurate figures. I have.

Hereinafter, a conventional printing apparatus will be described.
FIG. 10 is an exploded perspective view of a conventional printing apparatus. FIG.
, 1 is a frame forming a bottom plate made of a sheet metal. Reference numerals 2 and 3 denote side plates fixed to the frame 1.
The paper guide plate 8, the platen holder 15, and the sliding shaft 7 are supported and fixed. 4 is a frame 1 having a cam slope 4b
, A print head, and 6 a carriage to which the print head 5 is attached. Here, the rack 4 meshes with a gear 6b directly connected to a motor 6a mounted on the carriage 6 when the carriage 6 moves left and right, and is pressed against the gear 6b by a spring 4a. further,
The carriage 6 is provided with a head-up cam 6c which is guided by the cam slope 4b of the rack 4 and rotates. The print head 5 is pressed against the thermal paper 16 by a coil spring 5a disposed between the print head 5 and the carriage 6, receives electric energy from a flexible printed wiring board (hereinafter, referred to as "FPC") 5b, and performs printing. Do. The carriage 6 is moved in the left and right direction on the sliding shaft 7 by the motor 6a and the rack 4.

Reference numeral 8 denotes a paper guide plate for guiding the thermal paper 16 to a position where the print head 5 is located. Reference numeral 9 denotes a pinch leaf spring which is fixedly welded to the paper guide plate 8 and presses the thermal paper 16 against the paper roller 10a. A paper feed roller shaft 11 provided at a predetermined position is a ratchet wheel fixed to the paper feed roller shaft 10 and having radial claw teeth 11a formed on an end surface thereof. 11
A ratchet gear 12 having pawl teeth for engaging with a is slidably disposed. This portion is a one-way clutch that rotates only in one direction. A small track 14a formed at the tip of the cam plate 14 is engaged with the ratchet gear 12, and a pin (not shown) formed on a part of the carriage 6 is fitted into the curved groove 14b of the cam plate 14. ing.
The platen 17 is slidably supported on the platen holder 15.

[0006] The operation of the printing apparatus constructed as described above will be described below. FIG. 11 is a diagram illustrating a state of the print head 5 as the carriage 6 moves.

First, the thermal paper 16 is inserted from the rear of the paper guide plate 8 and passes between the pinch leaf spring 9 fixed to the paper guide plate 8 and the rubber roller 10a, thereby causing the platen holder 1 to move.
The platen 17 is sent out to the position of the platen 17 fixed at 5.

Next, a motor 6a mounted on the carriage 6
, A gear 6b directly connected to the motor 6a is engaged with the rack 4, and the carriage 6 is moved along the sliding shaft 7,
Move right or left. For example, when moving right,
By applying heat energy synchronized with the sliding of the carriage 6 to the print head 5, the thermal paper 16 is selectively colored to print characters. When one line is printed,
The cam plate 14 is moved by the pins implanted on the carriage 6.
Swings, and the ratchet gear 12 engaged with the small track 14a at the tip thereof rotates by a fixed amount, and the rotation is performed by the ratchet wheel 11
And the rubber roller 10a is rotated and fed by a predetermined amount. The head-up cam 6c completes the detaching operation at the end point of the cam slope 4b, and returns to a return spring (not shown).
Rotates in the opposite direction within the stable separation region.

[0009]

However, in the above-described conventional configuration, not only the number of parts is large, the material cost and the number of assembling steps are increased, but also the paper feeding accuracy is problematic. One of the problems in paper feeding accuracy is that when the recording paper is cut by a paper cutter after printing, the ratchet portion is a one-way clutch 12, so it is free from tension in the forward direction,
There has been a problem that the paper is pulled out or the engagement of the ratchet portion is displaced, and the line feed pitch is disturbed during the next line printing. Another problem with the paper feed accuracy is that the platen 17 that can swing is used, and when the paper is fed upward while contacting the platen 17 during paper feed, the inclination of the platen 17 is reduced due to frictional resistance between them. As a result, the recording paper 16 becomes slack, which causes a variation in line feed accuracy when printing the next line. Further, when the print head 5 is pressed against the platen 17 and the head detachment stability of the head-up cam 6c is released by the step of the cam slope 4b, the force of the head pressure spring 5a works suddenly, so that a collision sound is generated. Had the problem of doing so.

The present invention solves the above-mentioned conventional problems, and provides a printing apparatus which simplifies a paper feeding mechanism of the printing apparatus, improves paper feeding accuracy, reduces noise, and improves paper position detection accuracy. The purpose is to do.

[0011]

In order to achieve this object, a printing apparatus according to the present invention is provided with a paper guide formed on a part of a frame and guiding recording paper, and swingably supported by the frame. A platen, a paper feed roller rotatably arranged on the frame, and a print head that reciprocates with respect to the recording paper on the platen, form a gear integrally with the paper feed roller, and mesh with the gear. A rack portion for intermittently rotating the paper feed roller is provided, and a projection for engaging the gear of the paper feed roller and locking the rotation when necessary is provided on the rack portion.

[0012]

With these arrangements, it is possible to provide a printing apparatus which has a small number of components, is easy to assemble, and has a high paper feeding accuracy.

[0013]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described.

FIG. 1 is an exploded perspective view of a first embodiment of the present invention, FIG. 2 is a partial sectional view thereof, FIG. 3 is an overall view thereof, and FIG. 4 is a sectional view thereof.

In each of the figures, reference numeral 20 denotes a box-shaped frame made of a resin material, in which a paper guide portion 20a, a frame rack 20b, frame side walls 20c and 20d and the like are integrally formed. Reference numeral 22 denotes a print head for coloring the thermal paper. Reference numeral 23 denotes a heat radiating plate for fixing the print head 22. The heat radiator plate is supported by a carriage 26 so as to be swingable, and is pressed by a torsion spring 24 so as to contact a platen 28 to print. -It forms a drive unit. 21 is a metal swing shaft,
The paper feeding and printing operation is performed by operating the printing / driving unit right and left. Reference numeral 27 denotes a flexible printed wiring board (hereinafter, referred to as “FPC”), which supplies electric energy to the print head 22 and the like. Reference numeral 25a denotes a stepping motor mounted on a carriage 26, the rotation of which is transmitted to a frame gear 25, which is engaged with a frame rack 20b.

Reference numeral 20h denotes a first cam slope provided on the frame 20. The first cam slope 20h contacts the head-up cam 38 provided on the same plane as the frame gear 25 of the printing / driving unit, thereby moving the printing head 22 from the platen 28. Withdraw.

Reference numeral 20i denotes a second cam slope having a slope in a direction facing the platen 28 from the frame side wall 20c toward the outer wall of the frame 20. Let go.

On the other hand, the flat plate spring 30 has a notch 30b on the inner surface as shown in FIG. 5, and has a shape having an ear portion 30a protruding toward the end face from the notch 30b.
As shown in FIG. 4, the leaf spring 30 is inserted into the vertical slit 20e of the frame 20 from above. That is, when the leaf spring 30 is tilted to the angle of the solid line, the position of the ears 30a on both sides of the leaf spring 30 is regulated by the wall 20f formed in the paper guide. In this state, the rubber roller shaft 31a is rotatably supported by the frame 20, and the rubber roller 31 is moved to the position shown in FIG.
When the recording paper 3 is set at the position
2 are held in this part. At this time, as shown in FIG.
By pressing both ends of the plate spring 30, the leaf spring 30 is moved as shown in FIG.
Flexure occurs in the vertical A and horizontal B directions shown in FIG. Also,
A spring 35 is provided so that the gear teeth 33a on the end face of the gear 33 formed integrally with the rubber roller shaft 31a and the ratchet teeth 34a on the end face of the ratchet gear 34 always engage.
Pressed by. Reference numeral 36 denotes a cam plate.
d, the cam rack 36a formed at the tip of the cam plate 36, as shown in FIG.
Are in mesh with the ratchet gear 34. A pin 25b formed as a part of the carriage 26 is fitted into the curved groove 36c on the cam plate 36. When the carriage 26 moves left and right on the swing shaft 21, the cam plate 36 and the cam rack 36a are moved. The rubber roller 31 swings and is converted into rotation of the ratchet gear 34, and the rubber roller 31 rotates by a certain amount in one direction via the gear 33.

At the end of one line of paper feeding, that is, at the left end of the frame 20, a projection 36b formed as a part of the cam plate 36 engages with the gear 33, and at this position, the gear 3
3 and the rubber roller 31 integrated therewith are also locked.

Reference numeral 28 denotes a platen, which is fixed to a platen holder 29. The platen holder 29 is supported by the frame 20 so as to swing about a fulcrum 29a. When the recording paper 32 is fed, the print head portion which has been pressed against the recording paper 32 escapes in the direction of the arrow shown in FIG.
Line feeds. At this time, an elastic torsion spring 37 urges the recording paper 32 in contact with the platen 28 in a direction to prevent the platen 28 from tilting due to frictional resistance.

The torsion spring 37 is hung between a fulcrum 29a formed on a part of the platen holder 29 and a support 20g formed on a part of the frame 20, and acts in a direction to separate the two supports by its elasticity. 29a, support 20g, 29
Keep the posture so that b is in a straight line.

The operation of the printing apparatus configured as described above will be described. FIG. 8 is a diagram showing a state of the print head 22 as the carriage 26 moves.

First, the recording paper 32 is inserted from the back of a paper guide 20a formed integrally with the resin frame 20, passed between the leaf spring 30 and the rubber roller 31, and sent out to the position of the platen 28.

Next, when the stepping motor 25a mounted on the carriage 26 is rotated, the frame rack 20
The rotation is transmitted to the frame gear 25 engaged with b.
The entire printing and driving unit runs by itself. Printing is sequentially performed by the print head 22 while the printing / driving unit moves rightward.

Next, when printing is completed, the printing / driving unit moves in the opposite direction (left direction), and the first cam slope 20h
The print head 22 is detached from the platen 28 by contacting the head-up cam 38 provided on the bottom surface of the carriage 26 with the second cam slope and the radiator plate 23 when the print / drive unit moves leftward. Abuts on the first cam slope and the platen 2 of the head-up cam 38.
8, the print head 22 is detached more than the print head 22 is detached. During this time, the cam plate 36 and the cam rack 36a are oscillated by the pins 25b formed on a part of the carriage 26 to feed one line of paper.

Next, when the paper feeding is completed, the sheet moves to the right again, printing is performed as described above, and the cam plate 36 returns to the original position. At this time, the rubber roller does not rotate due to the one-way function of the ratchet portion.

Finally, when all the printing operations are completed, the printing / driving unit stops at the left end, and the above-mentioned projection 36b
3 and the rubber roller 31 is locked at this position.

In this embodiment, the cam plate is employed as a means for driving the ratchet mechanism. However, a similar method can be obtained by driving the rack by a method other than this method.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described.

FIG. 9 is an exploded perspective view of a second embodiment of the present invention. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 9, reference numeral 40 denotes a frame made of resin, 22 denotes a print head, which is supported by a carriage 26 and is pressed against a recording paper (not shown) and a platen 28 by a pressing force of a torsion spring 24, and electrical energy is supplied by an FPC 27. And print. Reference numeral 26 denotes a carriage having a stepping motor 25a for moving in the left-right direction and a frame gear 25 for moving, and constitutes a printing / driving unit.

The frame 40 has a bottom plate 40a and side plates 40b provided at both ends of the bottom plate 40a, and a paper guide 40c for guiding recording paper to a printing position.
Are disposed by integral molding so as to stand on the bottom plate 40a. The frame 40 has a paper guide 40c.
An elastic piece 40e for pressing the recording paper against the paper feed roller 31 is integrally provided by providing a slit 40d on a part of the wall. Also, the carriage 26 is provided on the frame 40.
And a wall 40g provided between the sliding shaft 40f and the bottom plate 40a of the frame 40 so as to support the sliding shaft 40f by integral molding. Furthermore, an elastic wire 41 is disposed between the paper guide 40c and the elastic piece 40e, and the elastic force of the elastic piece 40e is always maintained at a certain level or more irrespective of a change in environmental temperature.

The operation of the printing apparatus configured as described above will be described. First, a recording paper is inserted from the rear of a paper guide 40c integrally formed with the resin frame 40, and an elastic piece 40 independently formed on a part of the paper guide 40c.
The pressing pressure on the paper feed roller 31 against which the elastic piece 40e and the elastic piece 40e are pressed against each other is always kept at a certain level or more.

Next, a rotation signal is given to a stepping motor 25a mounted on the carriage 26, and the frame gear 25 directly connected to the stepping motor 25a is engaged with the frame rack 20b formed integrally with the frame 40, so that the carriage 26 is integrated with the frame 40. Molded sliding shaft 40
Move left and right along f. In this state, heat energy synchronized with the movement of the carriage 26 is transferred to the print head 22.
, The recording paper is colored and dots, lines, characters, etc. can be printed.

Next, when the printing is completed, the printing / driving unit moves in the opposite direction (left direction) to the first cam slope 20h.
The print head 22 is detached from the platen 28 by contacting the head-up cam 38 provided on the bottom surface of the carriage 26 with the second cam slope and the radiator plate 23 when the print / drive unit moves leftward. Abuts on the first cam slope and the platen 2 of the head-up cam 38.
8, the print head 22 is detached more than the print head 22 is detached. During this time, the cam plate 36 and the cam rack 36a are oscillated by the pins 25b formed on a part of the carriage 26 to feed one line of paper.

Next, when the paper feeding is completed, the sheet moves rightward again, and the printing is performed as described above, and the cam plate 36 returns to the original position. At this time, the rubber roller does not rotate due to the one-way function of the ratchet portion.

Finally, when all the printing operations are completed, the printing / driving unit stops at the left end, and the above-mentioned projection 36b
3 and the rubber roller 31 is locked at this position.

When the elastic piece 40e comes into contact with the paper feed roller 31 at two points and the distance over which the recording paper is wound around the paper feed roller is increased, the recording paper becomes
, The regulating force on the paper acts to reduce the influence of the external force on the paper feeding accuracy.

[0039]

As described above, according to the present invention, it is possible to realize a recording paper pinch mechanism which is simple and does not require a number of assemblings only by setting a flat plate spring. In addition, since the recording paper does not sag, the paper feeding accuracy is improved, and the line feed pitch is not disturbed because the paper feeding roller is locked even when the recording paper is cut.

Further, by detaching the print head from the platen in two stages, the load on the stepping motor can be divided into two, and a stable operation can be obtained. No impact and low noise can be achieved.

Further, by providing a notch groove in the leaf spring, the spring constant can be reduced. In addition, by providing the spring in two directions, it is possible to prevent the end face of the leaf spring from contacting the recording paper. As a result, the effect of stabilizing the insertability of the recording paper and preventing the end face of the leaf spring from damaging the recording paper during paper feeding can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial sectional view of the same.

FIG. 3 is an overall view of the same.

FIG. 4 is a sectional view of the same.

FIG. 5 is a front view of a leaf spring, which is an essential part of the same.

FIG. 6A is a cross-sectional view showing a state in which a leaf spring as the main part is attached to a vertical slit. FIG. 6B is a front view showing a state in which a leaf spring as the main part is attached to a vertical slit. Front view showing the relationship between the main part of the leaf spring and the rubber roller

FIG. 7 is a cross-sectional view between a frame and a paper feed gear, which are the main parts

FIG. 8 is a diagram showing a state of a print head accompanying movement of a carriage which is the main part.

FIG. 9 is an exploded perspective view of a printing apparatus according to a second embodiment of the present invention.

FIG. 10 is an exploded perspective view of a conventional printing device.

FIG. 11 is a diagram showing a state of a print head accompanying movement of the carriage.

[Explanation of symbols]

 20, 40 Frame 20a Paper guide 20e Vertical slit 22 Print head 28 Platen 30 Plate spring 31 Paper feed roller 33 Paper feed gear 36b Projection 37 Torsion spring

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B41J 19/78 B41J 19/78 H 25/308 25/30 G (56) References JP-A-3-275374 (JP, A) JP-A-3-42265 (JP, A) JP-A-5-338323 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 19/00 B41J 19/78 B41J 11/00 B41J 13/02 B41J 13/10 B41J 25/308

Claims (12)

(57) [Claims] 1. A paper guide formed on a part of a frame and guiding recording paper, a platen swingably supported by the frame, a paper feed roller rotatably disposed on the frame, and the platen. A print / drive unit for reciprocatingly printing on the upper recording paper, forming a paper feed gear unit integrally with the paper feed roller, and meshing with the paper feed gear unit to form the paper feed roller. A cam rack part for intermittently rotating the paper feed roller, and a projection for locking rotation by engaging with a paper feed gear of the paper feed roller when necessary in the cam rack part. 2. The printing apparatus according to claim 1, wherein the platen supported swingably is urged in one direction by an elastic body. 3. The recording paper is held by inserting a leaf spring into a vertical slit provided in the paper guide portion and pressing the recording paper against a paper feed roller by the elasticity of the leaf spring. The printing device according to the above. 4. The printing apparatus according to claim 3, wherein at least one notch groove is provided in a leaf spring inserted into a vertical slit provided in the paper guide portion, and the elastic direction of the leaf spring is plural. . 5. A printing apparatus comprising: a drive gear and a head-up cam provided on a carriage of a printing / driving unit; and a first cam slope which comes into contact with a frame and releases the recording paper from a platen by contacting the head-up cam. The printing device according to claim 1, wherein: 6. A radiator plate provided on an underside of a print head of a print / drive unit via an elastic body, and a radiator plate contacting the radiator plate to a frame to release the print head in the direction of recording paper. 2. The printing apparatus according to claim 1, further comprising two cam slopes. 7. A resin frame having a bottom and side plates provided at both ends of the bottom, and a paper guide are integrally formed so as to be erected on the bottom plate of the frame, and the paper guide is provided. 2. The printing apparatus according to claim 1, wherein an elastic piece for pressing the recording paper against the paper feed roller is integrally formed on a part of the wall. 8. A slit provided in a part of the paper guide, and an elastic piece is provided in the slit.
The printing device according to the above. 9. The printing apparatus according to claim 7, wherein, in the elastic piece for pressing the recording paper against the paper feed roller, two press contact portions are provided on one elastic piece for pressing against the paper feed roller. 10. The printing apparatus according to claim 7, wherein an elastic wire is disposed between a paper guide for guiding the recording paper and an elastic piece pressed against the paper feed roller. 11. A sliding shaft mounted on a frame for slidably supporting a carriage mounted with a print head and moving in the left-right direction, and a sliding shaft supported between the sliding shaft and a bottom plate of the frame. 8. The printing device according to claim 7, wherein the formed wall is integrally formed. 12. The printing apparatus according to claim 7, further comprising a paper feed roller in which a roller shaft having a rubber roller disposed at a predetermined position and a frame gear receiving rotation transmission of a motor are integrally formed of resin.