JP3361245B2 - Printer paper feed mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed mechanism of a printer, and more particularly, it presses a paper feed roller against a pressure contact roller to nip the recording paper and conveys the recording paper to a recording portion by rotating the paper feed roller. The present invention relates to a paper feeding mechanism of a printer suitable for performing.

[0002]

2. Description of the Related Art One line of recording is performed while moving a carriage equipped with a recording head along a platen, the one line of recording is performed, and then a sheet of paper is conveyed to the next line. Serial ink jet printers or thermal transfer printers that perform repeated recording to perform predetermined recording are often used as output devices for computers, word processors, etc. because of their high quality recording, low noise, low cost, and ease of maintenance. It is used.

FIG. 5 shows a thermal transfer printer which is an example of such a conventional serial printer.
A platen-shaped platen 2 is disposed in a substantially central portion of a frame 1 of the printer so that a recording surface thereof is substantially vertical, and a carriage shaft 3 is provided in front of and below the platen 2 of the frame 1. It is arranged parallel to the platen 2. A flange-shaped guide portion 4 is formed on the front edge of the frame 1, and a carriage 5 is provided on the carriage shaft 3 and the guide portion 4.
Are reciprocally mounted along the carriage shaft 3 and the guide portion 4. A thermal head 6 that is opposed to the platen 2 and that can be moved toward and away from the platen 2 by a drive mechanism (not shown) is attached to the tip of the carriage 5, and the upper surface of the carriage 5 is An ink ribbon (not shown) is housed inside, and a ribbon cassette (not shown) for guiding the ink ribbon between the thermal head 6 and the platen 2 is detachably attached. Further, the carriage 5
A winding bobbin 7 for winding the ink ribbon of the ribbon cassette and a delivery bobbin 8 on the delivery side are provided on the upper surface of the.

A sheet insertion port 9 for inserting a recording sheet (not shown) is formed at the rear of the platen 2, and the sheet inserted through the sheet insertion port 9 is placed on the platen. A paper feed roller 10 for transporting to the front of 2 (recording unit) is rotatably supported by bearings. Below the paper feed roller 10, a pressure contact roller 11 is provided.
Are arranged in parallel with the platen 2 so that they can contact the surface of the paper feed roller 10. The pressure contact roller 11 has a pressure contact roller shaft 11a.
It is formed so as to be rotatable integrally with. Further, the pressure contact roller shaft 11a is directly rotatably supported by a pressure contact roller holder (not shown) without using a bearing. here,
The pressure contact roller 11 is made of an elastic resin that does not contain a thermoplastic material because it may become hot during thermal sublimation printing. The pressure contact roller shaft 11a has a metal shaft whose surface is plated with Ni. It has been given a structure. Further, the pressing roller holder applies a pressing force to the pressing roller 11 by means of a biasing spring (not shown) provided inside, but in order to prevent creep deformation due to the spring force, a glass fiber of high strength is used. It is molded from plastic containing.

On the other hand, on one side surface of the frame 1, a paper feed gear 12 mounted coaxially with the paper feed roller 10 is arranged so as to project. The paper feed motor 1 is connected to the paper feed gear 12 via a plurality of transmission gears 13, 13.
4 is connected to the motor gear 15, and the paper feed motor 1
By rotating 4 the paper feed roller 10 rotates via the motor gear 15, each transmission gear 13 and the paper feed gear 12, respectively, and the paper feed roller 10 and the pressure contact roller 11 from the paper insertion port 9 are connected. The sheet inserted between them is pinched and conveyed.

In such a thermal transfer printer, a paper is inserted from the paper insertion port 9, the paper is nipped between the paper feed roller 10 and the pressure contact roller 11, and the paper feed motor 14 drives the paper feed roller. By rotationally driving the sheet 10, the sheet is conveyed to the recording start position in the direction orthogonal to the moving direction of the carriage 5. Then, while the thermal head 6 is in pressure contact with the platen 2 via the ink ribbon and the paper, the recording element of the thermal head 6 is selectively energized and driven based on image information while moving the carriage 5 along the platen 2. Then, the ink, which is the colorant, is partially transferred to the paper to perform desired recording. After that, the paper is conveyed every time the recording of one line is completed, and the recording of the next line is performed.

In such a thermal transfer printer, 1
Since the paper is conveyed by one line and the next line is recorded every time the recording of the line is completed, the paper conveyance accuracy is required to be high. This is because when the amount of paper conveyed is greater than a predetermined amount, a so-called white streak that is not recorded between lines occurs, and conversely, when the amount of paper conveyed is less than the predetermined amount, the overlap between lines occurs. This is because a so-called black streak will occur in a portion that is recorded twice.

In order to prevent this problem, the drive control method of the paper feed motor, which is the drive source of the paper feed roller, and the paper feed roller, which is the most important part of the paper feed mechanism, have been improved.

[0009]

However, in the conventional paper feeding mechanism of the printer, the pressure contact roller shaft 11a is directly supported by the pressure contact roller holder as the pressure contact roller 11 rotates, and the rotation is repeated. Of these, the glass fibers contained in the pressure contact roller holder damage the Ni-plated surface of the pressure contact roller shaft 11a, increasing the sliding load between them and reducing the amount of paper conveyed. There was a problem. For example, in the case of plain paper and thermal sublimation paper, the transport amount is reduced by about 0.6 to 0.8 mm with respect to 240 mm feed, and in the case of OHP sheet, the transport amount is about 1.0 to 1. It had decreased by 0.4 mm. Such a reduction in the amount of paper conveyed has been required to be improved because it becomes remarkable as a black line particularly when printing is performed by a color printer.

The present invention has been made in view of the above problems. By improving the lubricity and durability of the surface of the pressure roller shaft, the paper feeding accuracy can be maintained at high accuracy for a long period of time, and the recording quality can be improved. It is an object of the present invention to provide a paper feed mechanism for a printer that can improve the printer.

[0011]

In order to achieve the above object, the paper feeding mechanism of the printer according to the present invention is characterized in that at least the surface of the pressure contact roller shaft is at least the pressure contact roller holder.
Fluorine-containing nickel is used as a surface treatment with lubricity at the contact area.
It is a point that has been subjected to kel plating . By adopting such a configuration, the lubricity and durability of the surface of the pressure contact roller shaft can be improved, and the paper feeding accuracy can be maintained at high accuracy for a long period of time to improve the recording quality. it can.

Further, the paper feeding mechanism of the printer according to a second aspect is characterized in that at least the front surface of the pressure contact roller shaft is provided.
Surface treatment with lubricity at the contact area with the pressure contact roller holder
In principle, molybdenum compound coating or fluorination
It is the point that the compound coating treatment was applied. And such a structure
By adopting the structure, the pressure contact roller shaft
The surface lubricity and durability can be improved, and paper feeding
Accuracy can be maintained with high accuracy over a long period of time.
It

[0013]

[0014]

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a paper feeding mechanism of a printer of the present invention will be described below with reference to FIGS.

The same or corresponding components as those of the paper feeding mechanism of the conventional printer described above are designated by the same reference numerals, and the repetitive description will be omitted.

FIG. 1 shows a perspective view of the essential part of this embodiment, in which the pressure contact rollers 11, 11 ... Contact the surface of the paper feed roller 10 from above and convey the paper horizontally. However, it basically has the same configuration as the conventional one. However, in the present embodiment, the pressure contact roller shaft 11 which is the rotation shaft of the pressure contact rollers 11, 11 ,.
The difference is that the surfaces of a, 11a ... Are subjected to a surface treatment having lubricity.

That is, a cylindrical paper feed roller 10 made of a metal shaft is rotatably arranged in a horizontal direction by a bearing 10a. Above the paper feed roller 10, a plurality of pressure contact rollers 11, 11 ... Is the paper feed roller 10
Are arranged in the longitudinal direction and are supported by pressure contact roller shafts 11a, 11a ... The pressure contact roller shafts 11a, 11a ... Are fitted into the pressure contact rollers 11, 11 ... and are integrally formed, and the two arm portions 1 of the pressure contact roller holders 16, 16 ...
It is rotatably supported by 6a. The pressure contact roller holders 16, 16 ... Include a holder shaft 17 which is horizontally mounted on a supporting portion 1a fixed to the frame 1 and a base end portion 16b thereof.
Is rotatably supported at. This holder shaft 17
Is a sheet pressing lever 18 for pressing and releasing the pressure contact rollers 11, 11 ... With respect to the paper feed roller 10.
Are connected. In addition, the pressure contact roller holder 16,
A biasing spring 19 is disposed between the supporting units 1a and 16, and a biasing force for clamping the paper toward the paper feed roller 10 side around the holder shaft 17 is applied to the members 16. There is.

2 (a) and 2 (b) show the pressure contact and pressure contact release operations of the pressure contact rollers 11, 11, ... With respect to the paper feed roller 10. As shown in FIG. In FIG. 2A, the paper pressing lever 18 is rotated clockwise so that the biasing spring 1
2 shows a state in which the pressure contact rollers 11, 11, ... Are pressed against the paper feed roller 10 by the elasticity of FIG.
(B) shows that the paper pressing lever 18 is rotated counterclockwise against the elastic force of the urging spring 19 so that the pressure contact rollers 11, 1 are rotated.
1 shows a state in which the pressure contact of 1 ... Is released.

Further, the pressure contact roller holders 16, 16 ...
1 (the pressure contact roller holder 1 at the rightmost end in FIG. 1)
Next to (6), a paper detection roller unit 20 is rotatably mounted on the holder shaft 17 so as to check the paper before and after recording and to detect the top of the paper at the time of automatic paper feeding. .

On the other hand, a paper discharge roller 21 and a paper discharge cover 22 are provided in front of the paper feed roller, and the paper discharge cover 22 is urged toward the paper discharge roller 21 by the action of a spring (not shown). As a result, the recording-completed sheets are sandwiched and sequentially ejected.

Next, the surface treatment applied to the surfaces of the pressure contact rollers 11, 11 ... Will be described.

Since the members relating to the pressure contact rollers 11, 11 ... Are extremely small, the pressure contact roller holder 1
6 and 16 and the pressure contact roller shafts 11a, 11a ... There is no space for inserting a bearing dimensionally. Therefore, it is necessary to apply a surface treatment having lubricity to the pressure contact roller shafts 11a, 11a. ing. That is, as shown in FIG. 3, of the surfaces of the pressure contact roller shafts 11a, 11a ... At least the pressure contact roller holders 16, 16 ... And the sliding contact portion 23 are subjected to surface treatment having lubricity. In order to select this surface treatment, pressure contact roller shafts 11a, 11a ...
An experiment was conducted to see how much the reduction in the amount of paper conveyance could be suppressed when the paper was conveyed using a, 11a, ....

In the experiment, as surface treatment, nickel boron plating treatment, nitriding treatment, hard chrome treatment, fluorine-containing nickel plating treatment, molybdenum compound coating treatment and fluorine compound coating treatment were examined respectively, and the transport paper was plain paper. A transport error was measured by comparing this with a predetermined transport amount when transported by 240 mm. The results of this experiment are shown in Table 1.

[0025] From Table 1, the nickel-boron plating treatment, the nitriding treatment, and the hard chrome treatment reduce the sheet conveyance amount by about 0.6 mm, and the conventional pressure contact roller shaft 1
A sufficient effect was not obtained as compared with the case using 1a, 11a .... On the other hand, with the nickel-plated fluorine-containing material, the reduction in the paper transport amount is reduced by 0.1 to 0.2 mm.
With the molybdenum compound coating treatment, the reduction of the paper transport amount is 0.1 to 0.15 m.
m, and those subjected to the fluorine compound coating treatment were able to suppress the decrease in the amount of paper conveyed to 0.1 to 0.2 mm. As a result, in the case where the fluorine-containing nickel plating treatment, the molybdenum compound coating treatment, and the fluorine compound coating treatment are performed, the reduction in the amount of conveyed paper is reduced by about 1/3 to 1/6 as compared with the paper feeding mechanism of the conventional printer. Can be suppressed. Based on the above results, in the present embodiment, the pressure contact roller shafts 11a, 11a ...
As the surface treatment, it is preferable to perform one of a nickel plating treatment with fluorine, a molybdenum compound coating treatment and a fluorine compound coating treatment. For this reason, the pressure contact roller shafts 11a, 11a ...
6 can be prevented from damaging the surface of the pressure-contact roller shafts 11a, 11a ... With the glass fibers forming the pressure-contact roller holders 16, 16 ... be able to.

Therefore, according to an embodiment of the present invention,
Improving the lubricity and durability of the pressure contact roller shafts 11a, 11a ... By subjecting the surface of the pressure contact roller shafts 11a, 11a ... To one of a fluorine-containing nickel plating treatment, a molybdenum compound coating treatment, and a fluorine compound coating treatment. Therefore, it is possible to maintain high paper feeding accuracy for a long period of time and improve recording quality.

The present invention is not limited to the above-mentioned embodiment, but can be modified in various ways as necessary.

[0028]

As described above, according to the paper feeding mechanism of the printer according to the present invention, by improving the lubricity and durability of the surface of the pressure roller shaft, the paper feeding accuracy can be made high over a long period of time. There is an effect that the recording quality can be maintained and the recording quality can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of a paper feeding mechanism of a printer according to the invention.

FIG. 2A is an explanatory view showing a pressure contact state of a pressure contact roller with respect to a paper feed roller in the present embodiment,
FIG. 6B is an explanatory diagram showing a state in which the pressure contact roller is released from the pressure contact with the paper feed roller.

FIG. 3 is an explanatory diagram of a surface treatment applied to a pressure contact roller shaft in the present embodiment.

FIG. 4 is a configuration diagram showing a printer having a paper feeding mechanism of a conventional printer.

[Explanation of symbols]

10 Paper feed roller 11, 11 ... Pressure contact roller 11a, 11a ... Pressure contact roller shaft 14 Paper feed motor 16, 16 ... Pressure contact roller holder 23 Sliding contact part

Claims (2)

(57) [Claims] 1. A paper feed roller rotatably arranged by driving of a drive motor, a pressure contact roller arranged so as to come into contact with the surface of the paper feed roller, and a rotation unit formed integrally with the pressure contact roller. A pressure contact roller shaft and a pressure contact roller holder that rotatably holds the pressure contact roller shaft. When the paper feed roller rotates, the paper is conveyed by the paper feed roller and the pressure contact roller. Of the pressure contact roller shaft,
A paper feed mechanism for a printer, characterized in that a fluorine-containing nickel plating treatment is applied as a surface treatment having lubricity to a contact portion with the pressure contact roller holder . 2. Arranged to be rotatable by driving a drive motor.
The paper feed roller and the surface of this paper feed roller
Functioning pressure contact roller and the pressure contact roller
A pressure contact roller shaft that is rotatably formed, and this pressure contact roller shaft
And a press contact roller holder for rotatably holding the
By rotating the paper feed roller,
It was configured to convey the paper by the pressure contact roller
The paper feed mechanism, which has a smaller surface area than the pressure roller shaft.
Even if the contact part with the pressure roller holder has lubricity,
As a surface treatment to
A paper feed mechanism for a printer, characterized by being coated with a fluorine compound .