JPH0129088Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device for a serial printer using a wire dot type printing head, in which a ribbon mask for separating printing paper and an ink ribbon is attached and held between the tip of the printing head and the platen.

5, 6, and 7 show conventional embodiments, and in a serial printer using a wire dot type print head, the gap between the print head tip 21-2 and the platen 24 is A ribbon mask 26 made of thin material is installed on the printing paper 2.
7 and the ink ribbon 28 have been isolated to prevent troubles caused by contact between the two.

The ribbon mask 26 is provided with an opening 26-5 for the printing wire 23 to strike the ink ribbon 28 against the printing paper 27, and the printing paper 27 can run stably between the ribbon mask 26 and the platen 24. The gap G that is maintained is usually 0.25.
The printing paper 27 is very small at ~0.3 mm, so the printing paper 27 often comes into contact with the ribbon mask 26, and at that time, the printing paper 27 touches the edge of the opening 26-5 of the ribbon mask.
When setting the printing paper, the leading end of the printing paper 27 or the perforation of the printing paper tends to get caught, resulting in damage to the printing paper.

The object of the present invention is to eliminate the above-mentioned disadvantages and provide a device for attaching and holding a ribbon mask that allows printing paper to run stably.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a Syrian printer embodying the present invention. The carriage 2 carries the printing head 1 and the ribbon cartridge 9, is driven by a drive mechanism (not shown), and is driven by the platen 4.
Move the front side of the machine back and forth in the left and right direction. 3 and 3' are guide shafts that guide the carriage 2. 7 is printing paper. Reference numeral 6 denotes a ribbon mask made of a thin elastic material such as a stainless steel plate, which is installed between the holding member 5 provided on the carriage 2 and the nose end surface 1-1 of the printing head. 8 is an ink ribbon, which is stored in a ribbon cartridge 9. 1
0 and 11 are left and right frames of the printer, which hold the platen 4 and guide shafts 3 and 3'.

FIG. 2 is a front view of a printing device using an embodiment of the present invention, FIG. 3 is a plan view thereof, and FIG. 4 is a side sectional view thereof.

A printing wire 20 is aligned on the nose end surface 1-1 of the printing head 1 toward the platen 4. During standby, the printing wire 20 is located on the same plane as the nose end surface 1-1, and there is no space between the printing wire 20 and the platen 4. Gap A is maintained.

The ribbon mask 6 is made of a thin spring material, and both ends 6-1 are hook-shaped and engage with the holding member 5 so as to wrap around it, thereby restricting its displacement in the direction of the arrow 15. . Also ribbon mask 6
is provided with a square hole 6-2 (or may be a round hole), which engages with a protrusion 2-1 provided on the carriage to restrict displacement in the directions of arrows 12 and 13. Further, the lower end 6-8 of the ribbon mask 6 comes into contact with the upper surface 2-2 of the carriage 2, and prevents the ribbon mask 6 from rotating around the protrusion 2-1. A plurality of minute protrusions 6-3 and 6-4 having a height of B are provided on the surface of the ribbon mask 6 on the printing head 1 side.
-1 is in pressure contact. Further, a plurality of protrusions 6-5 and 6-6 are provided on the surface of the ribbon mask 6 on the side of the platen 4 around the opening 6-7, and these protrusions allow the printing paper 7 to be inserted into the opening provided in the ribbon mask. Part 6
-7 (the opening through which the printing wire 20 passes) to prevent the perforation of the page of the printing paper 7 from getting caught on the edge of the opening 6-7. The carriage 2 is provided with a protrusion 2-1 which engages with a square hole 6-2 of the ribbon mask 6 to restrict displacement of the ribbon mask 6 in the directions of arrows 12 and 13.

The two straight columnar holding members 5 provided on the carriage 2 are attached to the hook portion 6 of the ribbon mask 6.
-1, and restricts the hook portion of the ribbon mask 6 from being displaced in the direction of the arrow 15.

In order to obtain good printing quality, the gap A is set to a very small amount of 0.4 to 0.5 mm, taking into consideration the performance of the printing head, such as printing speed, copying ability, durability, and noise.

The gap B is formed by the minute protrusions 6 provided on the ribbon mask 6.
-3 and 6-4, and the size is the thickness of the ink ribbon 8 plus approximately 0.05 mm, so that the ink ribbon 8 is secured in the direction of the arrow 12. It is now able to drive stably.

The gap D is a gap through which the printing paper 7 passes, and if the thickness of the ribbon mask is C, then D=A-B-C, and is automatically set by attaching the ribbon mask 6. Now, assuming that A = 0.5 mm, C = 0.1 mm, and the thickness of the ink ribbon is approximately 0.1 mm, B = 0.1 +
0.05 and D=0.5-0.15-0.1=0.25mm.

Due to this gap amount, even if three or four sheets of copy printing paper are inserted, there is no resistance to the running of the printing paper, and the paper can be fed smoothly. Therefore, the gap necessary to demonstrate the basic performance of the print head is set, the printing paper 7 and the ink ribbon 8 are reliably separated, and the gap necessary for stable running of both is secured. It is very easy to stably hold the ribbon mask in the desired position.

When attaching and detaching the ribbon mask 6, since the ribbon mask itself has spring properties, the ribbon mask 6 has both ends 6.
-1 in the direction of the arrow 14, the ribbon mask 6 is bent in the direction of the arrow 17, and the square hole 6-2 of the ribbon mask 6 and the protrusion 2-
This can be easily done by disengaging the ribbon mask 6 from the ribbon mask 1 and pulling it upward.

As explained above, the printing device according to the present invention is
A plurality of minute protrusions are provided around the opening on the platen side surface of the ribbon mask, and these minute protrusions come into contact with the printing paper and guide the printing paper, making it difficult for the printing paper to come into contact with the edge of the opening. Since it is possible to guide the printing paper and keep the frictional resistance to a small value, when setting the printing paper
7 or the perforation of the printing paper gets caught in the opening, and allows the printing paper to run stably.Furthermore, the ribbon mask is made of elastic metal material. It is brought into contact with the tip of the nose part by force, and the distance from the tip of the nose to the opening and protrusion can be maintained at an accurate value, so an appropriate gap is secured between the printing paper and the ribbon mask, and the printing paper is It has the remarkable effect of making the running smoother and preventing staining of the printed paper caused by rubbing the printed paper against the ribbon mask.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a serial printer implementing the present invention, FIG. 2 is a front view of a printing device using an embodiment of the present invention, FIG. 3 is a plan view thereof, and FIG. 4 is a side sectional view thereof. FIG. 5 is a front view of a printing device showing a conventional embodiment, FIG. 6 is a plan view thereof, and FIG. 7 is a side sectional view thereof. 1, 21... Printing head, 2, 22... Carriage, 3, 23... Printing wire, 4, 24... Platen, 5, 25... Holding member, 6, 26... Ribbon mask, 7, 27... ...Print paper, 8,28...
…ink ribbon.

Claims (1)

[Claims for Utility Model Registration] In a wire dot printer that performs printing by hitting paper on a platen with a printing wire via an ink ribbon, a nose portion that holds a plurality of printing wires arranged in a direction toward the printing surface of the platen. a printing head supported movably in the direction of the printing digit, and a thin plate of a metal elastic material arranged between the nose portion and the paper and having an opening through which the printing wire passes. a ribbon mask, a plurality of protrusions are formed on the platen side near the opening so as to surround the opening, and the ribbon mask is brought into contact with the tip of the nose part by elastic force. A printing device characterized by: