JPH08310064A - Wire dot printer - Google Patents

Abstract

PURPOSE: To ensure a proper interval between a print head and a ribbon mask without wearing a nose end. CONSTITUTION: On a face opposite to a print head 10 of a ribbon mask 1, a protrusion 4 whose height does not exceed a thickness of an ink ribbon 8 is provided. The ribbon mask 1 is held in such a manner that the protrusion 4 does not butt against a nose end 11, so that a clearance between the print head 10 and the ribbon mask 1 is kept constant without wearing the nose end 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire dot type serial printer characterized by a ribbon mask.

[0002]

2. Description of the Related Art In a serial printer of the type in which recording and writing are performed on a recording sheet by a print wire, an elastic thin plate material is formed between a nose end of a print head and a platen, that is, a so-called platen gap. A ribbon mask is interposed so that the recording paper and the ink ribbon do not come into direct contact with each other.

The arrangement position of the ribbon mask in the platen gap has a great influence on the running of the ink ribbon. Therefore, the applicant of the present application discloses in JP-B-2-14422 that the surface of the ribbon mask facing the print head. In this paper, we proposed a printer in which a protrusion is provided which is slightly thicker than the thickness of the ink ribbon, and the protrusion is brought into contact with the nose end of the print head to determine the position of the ribbon mask.

However, in general, a ribbon mask has a print head formed of aluminum or plastic, whereas a ribbon mask is formed of a metal having high rigidity such as stainless steel. There is room for further improvement in that the nose end of the part that is in contact with is worn and the protrusion bites into it, and the gap between the nose end and the ribbon mask cannot be controlled constantly.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to:
An object of the present invention is to provide an improved ribbon mask capable of ensuring a constant gap between the print head and the ribbon mask without causing wear at the nose edge even after long-term use.

[0006]

That is, according to the present invention, as a wire dot printer for achieving such a problem, the thickness of the ink ribbon is provided above and below the ribbon running area on the surface of the ribbon mask facing the print head. The protrusions are provided so as not to exceed the height, and the ribbon mask is held so that these protrusions are always separated from the nose end of the print head.

[0007]

EXAMPLES Examples of the present invention will be described below. The drawings show embodiments of the present invention.

The ribbon mask indicated by reference numeral 1 in the drawing is positioned so as to be within a gap formed between the nose end 11 of the print head 10 and the platen 9, that is, the platen gap δ, and the nose of the print head 10. The print head 10 is carried on a carriage (not shown) at a constant interval so as not to come into contact with the end 11.

Like the conventional ribbon mask, this ribbon mask 1 is provided with a window hole 2 through which the print wire 12 is passed in the center thereof, and this area including the window hole 2 facing the print head 10 is The ink ribbon 8 forms a ribbon traveling surface 3 on which the ink ribbon 8 slides, and the upper and lower portions of the ribbon traveling surface 3, that is, the upper and lower portions of the ribbon traveling surface 3 deviating from the traveling path of the ink ribbon 8, The protrusions 4 having the same or slightly lower height are formed so as to protrude toward the print head 10. In addition, reference symbol S in the drawing indicates a recording sheet fed onto the platen 9.

In the embodiment configured as described above, the ribbon mask 1 for guiding the ink ribbon 8 by sliding contact with the ribbon running surface 3 has a print head 10 as shown in FIG.
It is carried by the carriage so as not to contact the nose end 2 of the.

Therefore, the ink ribbon 8 is fed by the ribbon running surface 3 and the end of the nose 11 while receiving some resistance, and the nose end 11 is fed to the ribbon mask 1.
There is no contact with the protrusion 3 provided on the end surface, and the end face is not worn.

On the other hand, when the recording paper S to be used is excessively thick with respect to the platen gap δ, the ribbon mask 1 is pushed toward the print head 10 so that the projection 3 is temporarily nose end 11.
However, even in such a case, the protrusion 4 keeps the distance between the ribbon mask 1 and the nose end 11 constant within the range of the load that the ink ribbon 8 can travel.

If a tip of the ink ribbon 8 is caught in the window hole 2 of the ribbon mask 1 when recording and writing on a new recording paper S, the ink ribbon 8 is divided into the nose edge 11 and the ribbon mask 1. As shown in FIG. 2, the leading end of the recording paper S penetrates deeper than the plate thickness of the ribbon mask 1 toward the nose end 11 because it is in sliding contact with the ribbon running surface 3 while being sandwiched between them. In no case, it immediately comes off the window hole 2 and returns to the normal state.

[0014]

As described above, according to the present invention, a projection having a height not exceeding the thickness of the ink ribbon is provided on the surface of the ribbon mask facing the print head, and the projection is always provided. Since the ribbon mask is held so that it does not contact the nose edge of the print head, the inconvenience of contacting the protrusion of the ribbon mask and abrasion of the nose edge is eliminated, and the durability of the print head is greatly improved. In addition, even if the ribbon mask is pressed against the print head side by the recording paper, these protrusions temporarily contact the nose edge, so that the ribbon can be moved within the range in which it can travel. The distance between the mask and the print head can be secured, and even if the edge of the recording paper enters the window hole, the ink ribbon prevents excessive entry. , It is possible to suppress the occurrence of such as a paper jam in advance.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a printer that is an embodiment of the present invention.

FIG. 2 is a diagram showing a state when a paper jam occurs in the printer.

[Explanation of symbols]

 1 Ribbon Mask 2 Window Hole 4 Projection 8 Ink Ribbon 9 Platen 10 Print Head 11 Nose Edge

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yukihiro Uchiyama 3-5 Yamato, Suwa City, Nagano Seiko Epson Co., Ltd. (72) Inventor Masayuki Kumasaki 3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Within the corporation

Claims (1)

[Claims] 1. A ribbon mask applied to a serial printer of the type for recording and writing on a recording paper by hitting an ink ribbon with a printing wire, the ribbon traveling area of a surface of the ribbon mask facing a print head. The upper and lower sides of the ribbon are provided with protrusions having a height that does not exceed the thickness of the ink ribbon, and the ribbon mask is held so that the protrusions are always separated from the nose end of the print head. Wire dot printer.