JPS6246852A - Medium conveying mechanism - Google Patents

Abstract

PURPOSE:To make the feed amounts of both upper layer paper sheet and lower layer paper sheet on a copying medium equal to each other, by providing a compensating pulley in the vicinity of a toothed pulley, the peripheral speed of the former being different from that of the latter, and by rotating the compensating roller while the compensating roller is made into contact with the copying medium. CONSTITUTION:A compensating roller 25 integrally mounted with a toothed roller 19 has a peripheral speed different from that of the toothed pulley 19, and further, in order to give a conveying force to a lower layer paper 14b, it has a large friction coefficient. The rotation of a drive shaft 23 is transmitted to the compensating roller 25 which is therefore rotated together with the toothed pulley 19, and a difference (delta) in wind-up speed, which is produced between upper and lower layer sheets 14a, 14b is recovered when the medium passes by a platen 13. As a result, since the feed amount of the upper and lower layer paper sheets are maintained to be equal to each other, the accumulation of either of upper and lower paper sheets is prevented, and thereby it is possible to eliminate slips of printing positions on the upper and lower layer paper sheets.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pin tractor bell)? The present invention relates to a media transport mechanism of a printer that transports print paper using a printer.

[Conventional technology]

Conventionally, this type of media transport mechanism has been developed by Japanese Patent Publication No. 57-598
There is something like that disclosed in No. 34.

FIG. 4 is a configuration diagram showing a conventional medium transport mechanism. In the figure, reference numeral 1 denotes a platen with a circular cross section.A medium 2 with a through-hole number is guided along a sheet guide 3 and wound around the pin 4a of a pin tractor 4. After the holes are engaged and the print head 5 arranged to face the platen 1 prints on the medium 2, the medium 2 is conveyed in the direction of arrow A.

5 is a side view of the pin tractor 4 in the conventional media transport mechanism shown in FIG. 4, and FIG. 6 is a sectional view taken along the line B-B. A pulley 77 and a pulley 8 are rotatably supported, and a tractor belt 9 with a pin for conveying a medium is attached between the toothed pulley 7 and pulley 8.

The tooth profile IJ 7 has a square hole, and the drive shaft 10
When the drive shaft 10 is fitted and rotated, the tractor belt 9 rotates, and the tractor frame 6
A medium 2 having a through hole installed between the tractor door 11 and the tractor door 11 is conveyed.

[Problem that the invention seeks to solve]

However, in this medium conveyance mechanism, since the medium 2 is wrapped around the circular platen 1, as shown in FIG.
When the copy medium 12 passes through the platen 1, the total thickness of the copy medium 12 between the upper layer paper 13 and the lower layer paper 14 is θ, and the length due to wrapping is A difference δ=tθ occurs.

Therefore, the copy medium 12 enters the pin tractor 4 with a deviation of the length difference δ, and the entire copy medium 12 is conveyed.

The circumferential speed of the platen 1 and the speed of the pin tractor belt 9 are generally set to be equal in order to improve the line feed pitch precision of printing when there is only one medium 2. As the paper passes, the difference in length between the upper layer paper 13 and the lower layer paper 14 is accumulated and added.

As a result, as shown in FIG. 8, there is a problem in that characters that should be printed on the same print line are printed at relatively shifted positions in the line feed direction on the upper layer paper 12a and the lower layer paper 12b of the copy medium 12. Ta.

Furthermore, if this amount of deviation increases, the through holes in the lower layer paper 12b of the copy medium 12 will come off the pins of the pin tractor belt 9, resulting in a fatal problem for the media transport mechanism in that the copy medium 12 cannot be fully transported. There was a problem in that it caused a problem.

[Means for solving problems]

The present invention provides a medium transporting medium having a curvature part such as a circular platen in the medium traveling path, a belt-shaped transporting member having a pin for transporting the entire medium, and a toothed pulley for fully driving the transporting member. In the mechanism, a correction roller having a peripheral speed different from that of the toothed pulley is provided in the vicinity of the toothed pulley;
The present invention is characterized in that the correction roller is rotated in contact with the medium.

[Effect]

According to the above configuration, the present invention drives the conveying member by the toothed pulley to convey the copying medium, and at the same time rotates the correction roller provided near the toothed pulley, so that the copying medium is continuously moved in parallel with the conveyance of the copying medium. All corrections can be made so that the lower layer can catch up with the conveyance of the upper layer.

〔Example〕

The entire embodiment will be explained below according to the drawings.

FIG. 1 is a side view of a main part of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line C--C, and FIG. 3 is an overall view of the embodiment.

In the figure, 13 is a platen with a circular cross section; 14 is a copying medium made up of a plurality of sheets having through holes that are wrapped around the platen 13 and facing the print head 15;
16 is a sheet guide that guides the entire copying medium 14 to the platen 13, and 17 is a pin tractor that transports the entire copying medium 14 in the direction of arrow A.

18 is a tractor frame, and the tractor frame 1
A toothed pulley 19 and a pulley 20 for driving are rotatably supported on the toothed pulley 19 and pulley 20.
A tractor belt 22 with a pin 21 for conveying the medium is attached between them.

Reference numeral 23 denotes a drive shaft fitted into the square hole 24 of the toothed pulley 19, and the drive shaft 23 is driven in the direction of the arrow by a power source (not shown).

A correction roller 25 is mounted integrally with the toothed pulley, and the correction roller 25 has a peripheral speed different from that of the toothed pulley.
4b is used to correct the feed amount.

Note that since the copying medium 14 is generally used with 3 to 5 copies of copying paper having a ream length of R34 to R45, the radius of the correction roller 25 in this embodiment is equal to the radius of the tractor belt 2.
2 to 0.3 mm, which is an amount corresponding to the thickness of the copy medium 14, from the running surface of No. 2.

Further, the surface of the correction roller 25 applies a conveying force of 2 to the lower paper 14b.
In order to increase the friction coefficient, the coefficient of friction must be increased.

Furthermore, a recessed portion is formed in accordance with the curved surface of the correction roller 25 at a position corresponding to the correction roller 25 on the tractor door 26 so that the correction roller 25 comes into sufficient contact with the lower layer paper 14b.

According to the above configuration, in this embodiment, the tractor belt 22 is rotated by rotating the drive shaft 23 in the direction of the arrow by a power source (not shown), and the tractor frame 18 is rotated.
The copy medium 14 wound around the platen 13 is conveyed in the direction indicated by the arrow while the pin 21 engages the through hole of the copy medium 14 loaded between the tractor door 26 and the tractor door 26.

At this time, the correction roller 25, which is mounted integrally with the tractor belt 22, directly receives the rotation of the drive shaft 23 and rotates together with the tractor belt 22.
The upper layer paper 14a of the copy medium 14 passes through the platen.
The length difference δ of the winding that occurs between the paper and the lower layer paper 14b is corrected by the correction roller 25.

Further, although not shown in the figure, the tractor belt 22 and the correction roller 25 can be driven by different drive sources or power transmission members.

〔Effect of the invention〕

As described above in detail, according to the present invention, a correction roller is provided integrally with the toothed pulley for driving the pin tractor belt, and corrects the transport distance of the lower layer paper of the medium so as to catch up with the lower layer paper. Since the feeding amount of the upper and lower layers of paper can be kept the same, it is possible to prevent the accumulation of misalignment between the upper and lower layers of paper.
This has the effect that the printing positions on the upper and lower layers of paper do not shift.

Similarly, since the accumulation of misalignment between the upper and lower layers of paper can be prevented, the feed hole of the copy medium and the pin of the pin tractor belt are always stably engaged, and there is no possibility of misalignment. This has the effect that the copy medium can be transported.

[Brief explanation of the drawing]

Fig. 1 is a side view of essential parts of an embodiment of the present invention, Fig. 2 is a sectional view taken along the line C-C, Fig. 3 is an overall view of the embodiment, and Fig. 4 shows a conventional medium transport mechanism. 5 is a side view of the pin tractor in the conventional medium conveyance mechanism shown in FIG. 4;
FIG. 6 is a sectional view taken along the line B-B, FIG. 7 is a side view of main parts showing the state of conveyance of a copy medium in the conventional medium conveyance mechanism shown in FIG. 4, and FIG. 8 is a cross-sectional view of the conventional medium conveyance mechanism shown in FIG. FIG. 6 is a diagram showing the result of copying by the medium transport mechanism. 14... Copy medium 18... Tractor frame 1
9... Toothed pulley 20... Pulley 21... Pin 22... Tractor belt 23... Drive shaft 25... Correction roller 26... Tractor door patent Applicant: Oki Electric Industry Co., Ltd. Agent Patent Attorney Takashi Kanakura 2 Side views of essential parts of this embodiment 1 Figure 1 Cross-sectional view taken along line C-C @ 2 B Overall view of this embodiment. 3. Here is a diagram showing the configuration of the conventional example. 4. A side view of the main parts of the conventional example. 5. B. A sectional view taken along line B-B in Figure 5. Written amendment (spontaneous) December 9, 1985 Michibu Uga, Commissioner of the Patent Office1, Indication of the case 1985 Patent Application No. 1858812,
Title of the invention Media conveyance mechanism 3, relationship with the person making the amendment JILll Patent applicant address 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Representative Nankai Hashimoto 4 , Agent 5, Date of amendment order: 0) 7. Contents of amendment 1. In the fourth line of page 7 of the specification, the phrase "the tractor belt 22 rotates" is corrected to "the toothed pulley 19 is rotated, thereby driving the tractor belt 22." 2. In the 9th line of page 7 of the specification, "tractor belt 22" is corrected to "toothed pulley 19." 3. "Tractor belt 22" on page 7, line 11 of the specification
The text has been corrected to read "tooth profile pulley 19". 4. Correct Figure 2 as shown in the attached sheet. Figure 1 C-C line cross section

Claims (1)

[Scope of Claims] 1. A belt-shaped conveyance member having a curved portion such as a circular platen in the traveling path of the medium, and a belt-like conveyance member having a pin for conveying the medium, and a toothed pulley that drives the conveyance member. A medium transport mechanism comprising: a correction roller having a circumferential speed different from that of the toothed pulley; and a correction roller provided in the vicinity of the toothed pulley, and the correction roller is rotated in contact with the medium.