JP3446782B2 - Wire dot printer - Google Patents

Description

Description: 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. 2. Description of the Related Art In a serial printer of a type in which recording and writing is performed on recording paper by a printing wire, an elastic thin plate material is provided between a nose end of a print head and a platen, that is, a gap called a platen gap. The recording paper and the ink ribbon do not come into direct contact with each other through the ribbon mask formed by the method described above. Since the position of the ribbon mask in the platen gap greatly affects the running of the ink ribbon, the applicant of the present invention disclosed in Japanese Utility Model Publication No. 2-144422 the surface of the ribbon mask facing the print head. Proposed a printer in which a projection slightly higher than the thickness of the ink ribbon is provided, and the projection is brought into contact with the nose end of the print head to determine the arrangement position of the ribbon mask. [0004] However, in general, the ribbon mask is formed of aluminum or plastic, whereas the print head is formed of a metal having high rigidity such as stainless steel. However, there is room for further improvement in that the nose end of the portion where the nose abuts is worn and the protrusion bites into the nose end and the gap between the nose end and the ribbon mask cannot be controlled uniformly. [0005] The present invention has been made in view of such a problem, and its object is to provide:
It is an object of the present invention to provide an improved ribbon mask that does not cause abrasion of the nose end even after long-term use and that can maintain a constant gap between the print head and the ribbon mask. That is, according to the present invention, as a wire dot printer for achieving the above object, a recording is performed by hitting an ink ribbon with a printing wire.
Suitable for serial printers that write data on paper.
A ribbon mask to be used, the thickness of the ink ribbon being equal to or less than the thickness of the ink ribbon above and below the ribbon running area on the surface of the ribbon mask facing the nose end of the print head.
Provided with a projection of the degree of height that can guide the Bonn, said protrusion is obtained so as to hold the ribbon mask so as to be separated from the nose end of always the print head. An embodiment of the present invention will be described below. The drawings illustrate embodiments of the present invention. The ribbon mask denoted by reference numeral 1 in FIG. 1 is positioned so as to be located within a gap formed between the nose end 11 of the print head 10 and the platen 9, that is, within the platen gap δ. The print head 10 is supported on a carriage (not shown) at a constant interval together with the print head 10 so as not to contact the end 11. The ribbon mask 1 is provided with a window 2 through which a print wire 12 is passed at the center thereof, similarly to a conventional ribbon mask, and this region including the window 2 facing the print head 10 includes: The upper and lower portions of the ribbon running surface 3, that is, the upper and lower portions deviating from the running path of the ink ribbon 8, form the ribbon running surface 3 on which the ink ribbon 8 slides. A protrusion 4 of the same degree or slightly lower is formed so as to protrude toward the print head 10 side. Note that reference numeral S in the figure indicates a recording sheet fed onto the platen 9. In the embodiment constructed as described above, the ribbon mask 1 for guiding the ink ribbon 8 by slidably contacting the ribbon running surface 3 is provided with a print head 10 as shown in FIG.
Is carried by the carriage so as not to contact the nose end 11 of the carriage. For this reason, the ink ribbon 8 is fed while receiving a slight resistance due to the contact between the ribbon running surface 3 and the nose end 11, and the nose end 11 is moved to the ribbon mask 1.
Without contact with the projections 4 provided on the end faces thereof, and no abrasion of the end faces thereof occurs. 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 and the projection 4 is temporarily moved to the 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 on which the ink ribbon 8 can travel. In the event that the leading end of the ink ribbon 8 is caught in the window hole 2 of the ribbon mask 1 during recording and writing on the new recording paper S, the ink ribbon 8 is moved between the nose end 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 due to the sliding contact with the ribbon running surface 3 while being sandwiched therebetween. It does not occur and immediately returns to the normal state by coming off the window hole 2 portion. According to the present invention as described above, according to the present invention, the following thickness of Lee down <br/> Kuribon, and the ink ribbon guide
It provided with a height of projections of the extent possible, normally since to hold the ribbon mask so that this projection does not contact the nose end of the print head, the nose end contacts the projection of the ribbon mask This eliminates inconveniences such as abrasion and greatly improves the durability of the print head, and even if the ribbon mask is pressed toward the print head by recording paper, these protrusions temporarily by contact with the end, in addition to it is possible to secure a distance between the ribbon mask and the printing head in a travelable range of the ink ribbon, the edge of the recording sheet Ribonmasu
Even if the paper enters the window of the paper, the ink ribbon can prevent the paper from entering more than necessary, and the occurrence of paper jam or the like can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a main part of a printer according to an embodiment of the present invention. FIG. 2 is a diagram showing a state of the printer when a paper jam occurs. [Description of Signs] 1 Ribbon mask 2 Window hole 4 Projection 8 Ink ribbon 9 Platen 10 Print head 11 Nose end

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yukihiro Uchiyama 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Masayuki Kumazaki 3-5-35 Yamato, Suwa-shi, Suwa, Nagano Say (56) References: Koepson Co., Ltd. Reference: JP-A-63-179140 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 11/62

Claims (1)

(1) A ribbon mask applied to a serial printer of a type in which an ink ribbon is hit by a printing wire to record and write on a recording sheet, wherein the ribbon mask is printed. Above and below the ribbon running area on the surface facing the nose end of the head , not more than the thickness of the ink ribbon and
A wire dot printer comprising a projection having a height sufficient to guide the ink ribbon and holding the ribbon mask such that the projection is always separated from a nose end of the print head.