JPS62234961A - Printer - Google Patents

Abstract

PURPOSE:To enable high-quality recording by making a platen with an elastomer coated around the periphery of a rigid roll in freely rolling manner and flattening a part which is a section of the rigid roll and opposed to a recording head. CONSTITUTION:A platen 3 is composed of a rigid roll 14 having any suitable number of recessed grooves 12... on the periphery and also a flat section 13 provided by notching a part opposed to a recording head 4 in axial direction, a suitable number of rollers 15... fitted freely rollable in a recessed groove 12 on the rigid roll body 14 and an elastomer 16 coated on the rigid roll 14 in freely rolling manner through the rollers. In printing state, the flat recording head 4 is pressed onto the flat section 14 from an arrow C direction. That is, an equal pressing force is given to the flat section 13 by the recording head 4. Thus, the characters of desired high quality are transferred to recording paper 2 held between the recording head 4 and the elastomer 16.

Description

[Detailed description of the invention] Industrial applications The present invention relates to printers, particularly thermal printers.

As shown in Figure 3, a thermal printer generally has a flat recording head C attached to a cylindrical platen b made of an elastic material such as rubber around which recording paper a is wound. It is pressed in the direction d to form a planar contact portion e, and the meltable ink on the recording paper a is heated and melted to print desired characters, etc. on the recording paper a. f, f is a drive roller, and g is a rolling roller, which function to smoothly convey the recording paper a in the direction of the arrow. Therefore, in the above thermal printer, since the platen b has a cylindrical shape, the pressing force at the upper end i and the lower end j of the contact portion e is greater than that at the center k of the contact portion e.
It had the disadvantage of being small and having poor printing quality.

As a means to solve this drawback, there are measures to increase the diameter of the platen b so that the abutting portion e is approximately flat, or to increase the pressing force of the recording head C. There arise problems such as an increase in size and deformation and deterioration of the platen b.

Therefore, as shown in Fig. 4, it has been proposed that a platen b is provided in the form of a flat plate to equalize the pressure contact force.
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However, in this method, it is necessary to newly provide a paper feed mechanism e, and the stability of recording paper insertion is lacking.Furthermore, there is a risk that the recording paper a may float when the recording head C is released from pressure contact, and the recording position may change. There is a problem that accuracy is reduced.

Furthermore, in recent years, a method has been proposed in which more power is supplied to the recording head in the vertical direction, where the pressure is lower than in the center, than in the center to make the print density more uniform.
(Japanese Unexamined Patent Publication No. 60-171177), this method attempts to solve the problem by controlling data, so it has the problem of being technically difficult (it is necessary to control each dot of the recording head). .

The present invention solves these conventional problems and provides a printer that can perform printing operations with accurately uniform print density without impairing the stability of recording paper insertion. purpose.

In order to achieve the above object, the present invention includes a carriage mechanism on which a recording head having an array of printing elements is mounted, and a platen around which recording paper is wound. In the printer that prints on the recording paper, the platen is composed of a rigid roll and an elastic body that is rotatably attached to the circumferential surface of the rigid roll, and is a part of the rigid roll and is connected to the recording head. The feature is that the part facing the is formed flat.

According to the above configuration, since the recording head is pressed flush against the flat part of the rigid roll, the pressing force is uniform, and desired characters can be printed with uniform density without impairing printing accuracy. be able to. Furthermore, since the elastic body is rotatably attached to the rigid roll, the recording paper can be conveyed easily and smoothly.

Dai-blood consistency Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

In FIG. 2, reference numeral 1 denotes a printer, specifically a thermal printer, which consists of a carriage mechanism 5 on which a recording head 4 having an array of printing elements is mounted, and a platen 3 around which recording paper 2 is wound.

The carriage mechanism 5 is a carriage (not shown)!
! A ribbon cassette 6 fixed in two rows, a flat recording head 4 arranged in a protruding manner on the ribbon cassette 6 and pressed against the platen 3, and a recording head connected to the ribbon cassette 6 through a winding mechanism (not shown). 4, an ink ribbon 8 stretched on the surface;
It consists of a guide rail 9 on which the carriage is suspended, and a drive motor 11 for reciprocating the carriage in the direction of arrow A via a timing belt 10.

As shown in FIG. 1, the platen 3 is provided with an appropriate number of grooves 12 on its circumference, and a notch is formed in the axial direction at a position facing the recording lid 4. A rigid roll 14 provided with a flat portion 13, an appropriate number of rollers 15 loosely fitted in the grooves 12 of the rigid roll 14, and the rollers 15. . . and an elastic body 16 rotatably attached to the rigid roll 14 via the elastic body 16. 17. 17 is a drive roller that is intermittently rotated by a drive motor (not shown), 18 is a roller that is pivotally supported at both ends, and the elastic body 16 is made of a rubber material such as chloroprene or NBR in a specific example. It is formed.

Therefore, in a printer equipped with the platen 3 formed in this manner, the recording paper 2 is inserted from the direction of arrow B, and the driving roller 17.1? It is held between the rolling roller 18 and the platen 3 and wound around the platen 3. In the printing state, the flat recording head 4 is pressed against the flat portion 13 from the direction of arrow C, as shown in the figure. In other words, a uniform pressing force is applied to the flat portion 13 by the recording head 4, and desired characters, etc. with good print quality are transferred onto the recording paper 2 held between the recording head 4 and the elastic body 16. . In this way, the carriage carrying the recording head 4 prints predetermined characters while moving in the direction of the arrow A, and then the drive rollers 17 and 17 press the recording paper 2 wound around the elastic body 16 while pressing the recording paper 2. The recording paper 2 rotates at a predetermined pitch, the recording paper 2 rotates together with the elastic body 16 of the platen 3, and is sent out in the direction of the arrow, line feed is performed, and the same operation is performed successively to perform the desired printing operation.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that the design can be changed without departing from the scope of the invention.

For example, the elastic body 16 may be made of plastic or the like with high elasticity.
It is also preferable to omit ....

As explained above, according to the present invention, the recording paper is During printing, a uniform pressing force is applied to the recording paper wrapped around the platen to print with uniform density without compromising the stability of conveyance, making it possible to perform high-quality recording.

In addition, compared to the conventional flat platen, the platen 3 of the present invention has a rolling elastic body to smoothly convey the recording paper 2, so the printing position accuracy is good, and the "
There is no misalignment, and the structure is simple.
It has the remarkable effect of easy maintenance and inspection.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 and 4 are sectional views of main parts showing a conventional example. 2... Recording paper, 3... Platen, 4... Recording head, 5... Carriage mechanism, 13... Flat part, 14
... Rigid body roll, 16... Elastic body. Patent Applicant Minolta Camera Co., Ltd. Representative Patent Attorney Tsukasa Nakajima Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] In a printer that includes a carriage mechanism 5 on which a recording head 4 having an array of printing elements is mounted, and a platen 3 around which a recording paper 2 is wound, the printer prints on the recording paper 2 via the recording head 4. 3 is made up of a rigid roll 14 and an elastic body 16 that is rotatably attached to the circumferential surface of the rigid roll 14, and a part of the rigid roll that faces the recording head is formed into a flat surface. A printer characterized by: