JPS604082A - Printer - Google Patents

Abstract

PURPOSE:To reduce load at the time of a head-up operation, contrive to conserve electric power and to enhance the speed of operation of a carriage and enable to freely select a material for a platen arm, by a method wherein a carriage for feeding a printing head rides onto a roller to push a platen arm, thereby performing a head-up operation. CONSTITUTION:At the time of the head-up operation, the carriage 7 moved in the direction of an arrow D rides onto the roller 14 protruding from the surface of the platen 4, through a protruding part 7a. At this time, both end parts 14b, 14d of the roller 14 are pressed against shoulder parts 3''b, 3''b of a groove 3''a, and the roller 14 is moved in the direction of an arrow C while being rotated in the direction of an arrow F. In this case, since there is a clearance between a central part 14a of the roller 14 and the bottom surface of the groove 3''a, the roller 14 can be rotated smoothly. By causing the carriage 7 to ride onto the roller 14, the platen arm 3'' is turned by being pushed in the direction of an arrow B against an energizing force of a spring 5, and a thermal head 8 and the platen 4 are separated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art] In this type of printing device, printing is performed by bringing the print head and platen into pressure contact with each other through the recording paper, but since the recording paper cannot be fed while the print head and platen are in pressure contact, the feeding of the recording paper is difficult. When printing, the print head and platen are separated from each other to perform a so-called head-up operation.

In the past, this head-up operation was performed using an independent drive source such as a dedicated lunoid, but recently, in order to save power, reduce costs, and downsize the device, the drive power of the motor for moving the print head has been increased. A method has been proposed in which heads-up is performed using

The conventional structure of such a printing device will be explained with reference to FIGS. 1 to 4. 1 and 3 are plan views of essential parts of the printing device, and FIGS. 2 and 4 are sectional views of FIGS. 1 and 3, respectively.

In each figure, the reference numeral 1 indicates a frame that supports each component of the printing device, and a platen arm 3 is attached to a shaft 2 horizontally mounted on the frame 1, which is indicated by arrows A, , I3 in the figure.
It is rotatably supported in the direction.

The platen arm 3 has a cross-sectional shape shown in FIG.
It is formed into a thick plate shape that is long in the axial direction, and an elongated frame-shaped platen 4 is fixed to the upper part of the front ridge. The first platen arm 3. At the left end in FIG. 3, a protrusion 3a is formed that protrudes from the surface of the platen 4 and has a slope on the right side in both figures.

Further, the platen arm 3 is always held in the first position by a spring 5 loaded between the back side of the platen arm 3 and the frame 1. It is biased in the direction of arrow A in FIG.

On the other hand, a guide shaft 6 is horizontally suspended on the frame 1 in parallel with the shaft 2, and a carriage 7 is slidably attached to the guide shaft 6, and is driven by an unillustrated drive means at the arrow C in FIG. , D direction.

A thermal head 8 is fixed to the front upper part of the carriage 7, facing the platen 5.

Also, the first section of the carriage 7. A protrusion 7a protruding leftward is provided on the left side of the front in FIG.
A curved surface is formed at the front left end.

The carriage 7 is pressed by the platen arm 3, which is biased in the A direction, via the platen 4 and the thermal head 8, and is pressed against the frame 1 extending from the rear side of the upper part, and is thereby guided. It is positioned in the radial direction of the shaft 6.

- A paper feed roller 9 and a pinch roller 10 are arranged below the blade shaft 2, and the recording paper 11 fed by both is guided between the platen 4 and the thermal head 8 and pressed into contact with it.

At the time of printing, the carriage 7 is in the position shown in FIG. 1, and the biasing force of the spring 5 presses the shim platen 4 against the thermal head 8 with the recording paper 11 in between. In this state, the carriage 7 is moved in the direction of arrow C in the figure, and the thermal head is driven once to perform printing.

When the thermal head 8 reaches the right end of the recording position and finishes printing the - line, the carriage 7 is moved in the direction of the arrow in FIG. 1 and returns to the initial position at the left end shown in FIG. 3.

At this time, on the slope of the protrusion 3a of the platen arm 3,
- When the ridge 7 rides up via the protrusion 1a, the carriage 7 presses the platen arm 3 in the direction of arrow B against the biasing force of the spring 5 and rotates it.

As a result, a gap is created between the sieve platen 4 and the thermal head 7, and the pressure contact between the recording paper 11 is released.

During this time, the recording claw 11 is advanced by one line in the direction of arrow E in FIG. 1 due to the rotational drive of the paper feed roller 90.

Thereafter, as the carriage 7 moves in the direction indicated by the arrow, the protrusion 7a descends the slope of the protrusion 3a, the platen 5 and the thermal head 8 are brought into pressure contact again, and the printing operation is resumed.

However, in the above operation, when the carriage 7 moves with its protruding portion 7a riding up the slope of the platen arm 3a and when it moves while descending, a larger load is applied compared to when the carriage 7 moves during printing and returning. . This is because an opposite force acts due to the biasing force of the spring 5, and the friction between the protrusions 3a and 7a is large because it is sliding friction.

Therefore, in the conventional structure, the torque is increased by lowering the frequency of the motor of the carriage driving means when the carriage is raised or lowered.

In addition, in connection with this, when the platen arm is made of a type of plastic with low sliding friction, this type of plastic suffers from large thermal deformation and deteriorates the precision of the parts.

In other words, in the case of a platen arm made of one piece of plastic, reducing sliding friction and increasing component accuracy are not compatible.

From the above, the conventional configuration has the drawbacks of high power consumption and inability to perform high-speed carriage operations.

Purpose The present invention has been made in order to eliminate the above-mentioned conventional drawbacks.The present invention has been made to solve the above-mentioned drawbacks of the conventional printer. The purpose of the present invention is to provide a printing device that can perform a close-up operation.

EXAMPLES The details of the present invention will be explained below based on examples shown in the drawings. In each figure, the same parts as in FIGS. 1 to 4 are denoted by the same reference numerals, and the explanation thereof will be omitted.

First Embodiment FIGS. 5 to 7 show an embodiment of the present invention. The configuration of this embodiment differs from the conventional configuration only in the configuration of the platen arm, so explanation of the other configurations will be omitted. .

As shown in Fig. 6, the overall shape of the platen arm 3' is formed almost the same as the conventional one, but a rotatable roller 12 is provided at the left end in Fig. 5 in place of the conventional protrusion 3a. ing.

As shown in FIG. 6, a short cylindrical roller 12 is rotatably supported via a shaft 13 in a groove 3'a formed at the left end of the platen arm 3'. Further, the outer peripheral surface of the front side of the roller 12 protrudes beyond the surface of the platen 4.

At the time of printing, the carriage 7 is in the position shown in FIG.
The carriage γ is pressed against the thermal head 8 with the paper 1 sandwiched therebetween, and the carriage γ runs in the direction of the arrow C to perform printing, as described above.

After printing of the - line is completed, the carriage 7 travels in the direction of the arrow and returns to the initial position at the left end shown in FIG. At this time, the carriage γ rides on the fortuner 12 protruding from the surface of the platen 4 via the protrusion 7a, moves while rotating the roller 12 in the direction of arrow F, and returns. This is sipratey
The arm 3' is rotated by being pressed in the direction of arrow B against the biasing force of the spring 5.

As a result, the platen 4 and the thermal head T are separated from each other, and the recording paper 11 is fed between them.

Thereafter, as the carriage 7 moves in the direction of arrow C, the protrusion 7a moves in the C direction while the rollers 12 rotate in the opposite direction to the P direction, and descends from the roller opening 12. As a result, the sieve platen 5 is brought into pressure contact with the thermal head 8 again, and printing is resumed.

In the above-described operation, when the carriage 7 moves while riding on the rollers 12 during the rad-up, the friction between the rollers 12 and the carriage 7 is very small due to rolling friction. Therefore, the load of the movement at this time is small, and the torque of the motor (not shown) that drives the carriage can be small. It is also possible to move the carriage at high speed.

Further, since the platen arm 3' and the rollers 12 are separate from each other, for example, the platen arm 3' is formed with high precision from a type of plastic that undergoes little thermal deformation, and the rollers 12 are formed from a type of plastic that has a small coefficient of friction. be able to.

Second Embodiment According to the configuration of the above embodiment, there is a step of press-fitting the shaft 13 into the platen arm 3 in order to attach the roller 12 during assembly, and an E-shaped retaining shaft or the like is used to prevent the shaft 13 from being removed. This increases the number of assembly steps. An embodiment that improves this point is shown in FIGS. 8(a) to 8(C) and will be described.

As shown in the figure, there is a groove 3 at the left end of the platen arm 3''.
``a'' is formed, and shoulders 3/'b and 3//b are formed on the upper and lower sides of this groove 3''a and are shallow, and the space between them is deep. Further, above and below the groove 3''a, bearing grooves 311c, 311c are formed on the inner side of the surface of the platen arm 3'' from the end surface of the platen arm 3'' to the middle of the width of the groove 3''a. Walls 3''cl, 3''d between the bearing grooves 3''c, 3''c and the platen arm 3'' serve as a pull-out stop.

A roller 14 is fitted into the groove 3''a.

The roller 14 has a stepped cylindrical shape with a large diameter at the center 14a and small diameters at both upper and lower ends 14b, 141).
Shaft portions 14C, 14C are integrally formed at the center of the end face.

The roller 14 is inserted into the shaft portion 14 from the end face of the platen arm 3'' before the platen arm 3'' can be removed from the frame 1 during assembly.
G, fit 14C into bearing grooves 3''c, 3''c,
The platen arm 3 is inserted into the groove 3″a.
By attaching `` to the frame 1, the frame 1 closes the end surface side of the groove 3''a, and prevents the roller 14 from being pulled out in the direction toward the end surface side. In the front direction, the walls 3''d and 3''d prevent the roller 14 from coming off. Further, the outer peripheral surface of the roller 14 protrudes beyond the surface of the platen 4.

When the head is up, the carriage 7, which moves in the direction of the arrow as shown in FIG. 8(a), rides up onto the rollers 14 that protrude from the surface of the platen 4 via the protrusions 7a. At this time, as shown in FIG. 8(c), both ends 14b of the roller 14,
14b is pressed against the shoulders 3/'b and 31Lb of the groove 3''a, and the roller 14 rotates in the F direction in FIG. 8(a) and moves from the center to the C direction.
Since there is a clearance between the groove 4a and the bottom surface of the groove 3''a, the roller 14 can rotate smoothly.

As in the previous embodiment, when the carriage 7 rides on the rollers 14, the platen arm 3'' is pressed in the direction B against the biasing force of the spring 5 and rotates, thereby separating the thermal head 8 and the platen 4. The following operations are also similar to those in the previous embodiment.

According to the above structure, the same effects as in the previous embodiment can be obtained, and in order to install the roller 14, it is only necessary to fit the roller 14 into the groove 3''a during assembly. The assembly process can be simplified compared to the embodiment.

In the above embodiment, the rollers 12 and 14 are formed in a cylindrical shape, but they may be spherical or other shapes.They are used as a support for a platen in a printing device that performs printing by bringing a platen and a print head into pressure contact with each other through a recording paper. The platen arm is equipped with rotatable rollers that protrude from the platen surface, and the carriage for transporting the print head rides on the rollers and presses the platen arm to perform head-up. The load on the platen arm is small, saving power and increasing the speed of the carriage operation, while providing greater freedom in selecting the material for the platen arm.

[Brief explanation of the drawing]

Figures 1 to 4 explain the configuration and operation of the main parts of the conventional device. Figure 1 is a plan view of the main parts during printing, and Figure 2 is the first
3 is a plan view of the main parts when the head is up, FIG. 4 is a longitudinal side view of FIG. 3, and FIGS. 5 to 7 illustrate the first embodiment of the present invention. Fig. 5 is a plan view of the main parts during printing, Fig. 6 is a vertical side view of the platen arm, Fig. 7 is a plan view of the main parts when the head is up, and Fig. 8 (
8(a) is a plan view of the main part, FIG. 8(b) is a front view of the narrow part, and FIG. C) is a sectional view taken along line A-A in FIG. 8(b). 3', 3''...Platen arm 3/a, 3//a・
・Groove 4 ・Platen 5 ・Spring 7 ・Carriage 7a ・Protrusion 8 ・Thermal head 11 ・Recording paper 12.14
...Koro. Patent applicant Canon Corporation M1 Figure 3 Section 5 Figure 2 Figure 1 Figure 4 Figure 6

Claims (1)

[Claims] 1) In a printing device that performs printing by pressing a platen and a print head into contact with each other via recording paper, a rotatable roller protruding from the platen surface is provided on the support of the platen to transport the print head. A printing device characterized in that a carriage rides on the rollers and presses the support body to separate the print head and the platen. 2) The printing device according to claim 1, wherein the roller is fitted into a groove formed at an end of the support, and a frame of the printing device is used to prevent the roller from being pulled out. The present invention relates to a printing device such as a thermal type or a thermal transfer type that prints by bringing a platen and a print head into pressure contact with each other.