JPH0143246Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressing roll for pressing recording paper against a thermal head of a thermal recording device.

In thermal recording devices used in printers such as word processors and telefaxes, the first
As shown in the figure, heat-sensitive recording paper that develops color when heated or plain paper overlaid with an ink donor sheet is passed through the heat-generating resistors arranged in a line on the surface of the thermal head 4 while being pressed by the press roll 1. recording is performed.

The pressing roll 1 has a bearing 5 that supports both ends of the core shaft 2.
is pressed toward the heat-sensitive head 4 by a spring 6.

The conventional pressing roll 1 has a cylindrical solid rubber layer 3 formed on the outer periphery of the core shaft 2 so that the recording paper comes into close contact with the thermal head, but poor adhesion between the thermal head and the recording paper may cause blurred printing. In some cases, the outline became unclear.

In order to prevent blurred printing and unclear outlines, the pressing roll should have a small surface rubber layer and compression set, be resistant to abrasion with the paper, have a stable coefficient of friction with the paper, and have a low pressing pressure. Rubber hardness is required to be small so that it can be sufficiently deformed even if it is small, and that the physical properties change little due to environmental changes such as temperature and humidity. Rubber hardness is in the range of 20° to 50° on the JIS A scale. things are used.

When the rubber hardness is low, with a JIS A scale of 20° to 50°, the green strength in the unvulcanized rubber is extremely weak due to the presence of softeners such as oil and sub-rubbers, so it is made into a pipe shape using an extruder. There were also molding problems, such as the so-called sagging phenomenon in which the rubber could not maintain its original shape even when extruded, and it was difficult to mass-produce.

Furthermore, since a large amount of softening agent is mixed into the rubber, there are problems with adhesion to the metal core, such as peeling of the adhesive.

The present invention is an attempt to improve the problems encountered during roll manufacture and the printing defects caused by poor adhesion between the rubber layer and the core metal during actual use.

In order to achieve this purpose, the pressing roll for the heat-sensitive recording device of the present invention has a surface layer 7 made of natural or synthetic rubber.
A knitted fabric layer 8 made of natural or synthetic fibers is integrated to form a rubber band, which is then tightly fitted onto the outer peripheral surface of a metal core 9 for rolls.

The manufacturing method is to cover a core for vulcanization with a cylindrical knitted fabric knitted with a knitting machine to form a knitted fabric layer, and if necessary, the surface of the fabric is treated with an adhesive, and then an extrusion machine is applied on top. A surface layer is formed by covering the extruded unvulcanized tube, and the required dimensions are created through vulcanization, polishing, and cutting processes.

This rubber tip is measured by diameter against the metal core for roll.
A roll is manufactured by providing an expansion allowance of 0.01 to 1.0 mm and fitting tightly together.

When compared with a conventional metal core metal that uses direct adhesive to integrate low-hardness rubber with the same hardness,
Since the volume of each low-hardness rubber product is small, there is little deformation due to so-called sag during roll manufacturing, and the manufactured rubber can be inserted into the metal core for rolls while providing a tightening margin of 0.01 to 1.0 mm in diameter. Therefore, due to this binding force, peeling between the rubber surface layer and the textile fabric layer does not occur, and of course, the rubber tip does not come off from the core bar.

The rubber used here is selected from natural and synthetic rubbers, especially chloroprene rubber, silicone rubber, ethylene-propylene terpolymer rubber,
Acrylonitrile rubber and polynorbornene rubber are preferred.

Further, the hardness of the surface layer rubber is preferably in the range of 10° to 50° on the JIS A scale.

In addition, the textile fabric layer made of natural or synthetic fibers is preferably made of nylon, cotton, polyester, or a blend thereof, and formed using a loom, knitting machine, etc., into a cylindrical shape, but is not limited thereto. isn't it.

Furthermore, the outer diameter of the pressing roll is usually 20 to 30 mm and the outer diameter of the roll core is 10 to 15 mm, but the tightening margin of the rubber tip to tightly fit the roll core is 0.01 to 1.0 mm to the core. A range is preferred.

Examples will be described below.

[Example] A 6.6-thick nylon cylindrical body knitted by a knitting machine is placed over a vulcanizing core metal having the required dimensions, and a rubber adhesive is brushed onto the cylindrical body.

Furthermore, after covering the pressed tube with unvulcanized acrylnitrile rubber compounded to JIS A scale of 30° and tightening it with a tie, etc., it was heated to 150°C.
Vulcanize for hours.

After vulcanization, the mold is removed, polished, and cut to an outer diameter of 20 mm.
A rubber tip with an inner diameter of 11.7 mm and a length of 200 mm was obtained.

This rubber piece was fitted into a metal core with an outer diameter of 12 mm and a length of 230 mm using a fitting machine.

This roller does not suffer from deformation due to sagging during manufacturing, and can maintain stable printing performance even when used in a thermal printer for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a thermal recording device, and FIG. 2 is a sectional view of a pressing roll for a thermal recording device according to the present invention. 1... Pressing roll, 2... Core shaft, 3... Solid rubber layer, 4... Thermal head, 5... Bearing, 6...
Spring, 7...Surface layer, 8...Knitted fabric layer, 9...Metal core for roll.

Claims (1)

[Claims for Utility Model Registration] 1. The surface layer 7 made of natural or synthetic rubber and the textile layer 8 made of natural synthetic fiber are integrated to form a rubber band, and then tightly fitted onto the outer peripheral surface of the metal core 9 for rolls. Press roll for thermal recording device. 2 The hardness of the surface layer made of natural and synthetic rubber is JIS
The pressing roll for a heat-sensitive recording device according to claim 1, characterized in that the A scale is in the range of 10° to 50°. 3. The pressing roll for a thermal recording device according to claim 1, wherein the textile fabric layer made of natural or synthetic fibers is made of nylon, cotton, or polyester. 4. The pressing roll for a heat-sensitive recording device according to claim 1, wherein the tightening margin of the rubber tip for tightly fitting the roll core is 0.01 to 1.0 mm with respect to the core.