JPH11240644A - Paper feeding mechanism for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the rotation of a paper feeding roller, which does not cause unevenness in rotation even when a backlash occurs, and enable the feed of recording members at a uniform and stabled paper feed to be performed. SOLUTION: With the paper feeding mechanism of a printer, in either operation of the first and second paper feeding operations, a paper feed roller 11 is rotated in the direction of the arrow D to pull out the top of a recording member 8. Thus, the throughout can be improved, and even when a backlash occurs in the paper feed roller 11, the paper feed roller 11 can be stably rotated without causing unevenness in rotation. Since unevenness in feeding the recording member 8 can be eliminated, high quality printed images can be obtained.

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 for a printer capable of easily removing backlash of a paper feed roller generated when a recording paper is manually fed to a paper feed roller.

[0002]

2. Description of the Related Art As shown in FIG. 6, a paper feed mechanism of a conventional printer includes a paper feed roller 11 and a paper feed roller 1 as shown in FIG.
1, a driving source 13 including a motor having a gear portion 13b meshing with the gear portion 12a of the intermediate gear 12,
1 and a driven roller 14 that rotates following the rotation of the paper feed roller 11. The operation of the paper feeding mechanism of the conventional printer having such a configuration is performed by the recording member 8.
Is manually sent in the direction of arrow R. Then, the driving source 13 is rotated in the direction of arrow B, and the recording member 8 is slightly conveyed downstream via the intermediate gear 12 by the paper feed roller 11 rotating in the direction of arrow D.

[0003] A minute gap (not shown) is generated in the tooth tip portion of the drive source 13, the intermediate gear 12, and the paper feed roller 11 when the gear portions 11a and 12a13b are in mesh with each other. Backlash occurs on the feed roller 11. When printing is performed using the paper feed mechanism of a printer having such a backlash, the rotation of the paper feed roller 11 varies by the size of the backlash,
There has been a problem that the printing quality of an image printed on the recording member is deteriorated due to the occurrence of a shift in the feeding of the recording member 8 or the like. In order to eliminate the backlash of the gear as described above, a highly accurate gear having no variation in the shape and dimensions of the tooth ridge is required. However, since such high-precision gears are very expensive, it has been difficult to use them in small printers and the like that require low prices.

Therefore, the operation of the paper feed mechanism of the conventional printer which does not degrade the print quality even if there is a backlash is to manually feed the recording member 8 to the paper feed roller 11 side.
By rotating the drive source 13 in the direction of arrow B and rotating the paper feed roller 11 in the direction of arrow D via the intermediate gear 12, the recording member 8 in the manually inserted state is slightly conveyed to the downstream side, The rotation of the drive source 13 is temporarily stopped. Thereafter, the rotation of the drive source 13 is reversed in the direction of arrow E, and the intermediate gear 12 is rotated.
To rotate the paper feed roller 3 in the direction of arrow G,
Until the recording member 8 does not come off the paper feed roller 11,
Slightly return to the upstream side in the arrow L direction.

Next, the drive source 13 is again rotated in the direction of arrow B, and the paper feed roller 11 is rotated via the intermediate gear 12 in the direction of arrow D.
The recording member 8 is rotated by a predetermined amount in the direction, and the cue of the recording member 8 is performed.
After the cue of the recording member 8, a desired image is printed on the recording member 8, and the paper feed roller 11 is rotated in the direction of arrow D,
The printed recording member 8 is discharged downstream of the paper feed roller 11. As mentioned above, the paper feed mechanism of a conventional printer is
After the recording member 8 is slightly conveyed to the downstream side of the paper feed roller 11 by the manual feed and the paper feed roller 11 rotating in the direction of arrow D, the paper feed roller 11 is once rotated in the direction of arrow G once,
The recording member 8 is returned to the upstream side in the arrow L direction. Thereafter, the paper feed roller 11 is again rotated in the direction of arrow D, and the recording member 8 is rotated.
Was conveyed to the downstream side so that the printed image was not affected by backlash.

[0006]

However, in the conventional paper feed mechanism as described above, when the recording member 8 is sent to the paper feed roller 11, the operation of sending the recording member 8 to the downstream side and the operation of the upstream side Since the backlash of the paper feed roller 11 is removed by the operation of returning to the printing operation, there is a problem that the time (throughput) from the start of transport of the recording member 8 by the operator to the end of printing is increased. . The present invention relates to a paper feed roller 1
(1) To provide a paper feed mechanism of a printer capable of always obtaining a stable high-quality print image by eliminating the influence of backlash, improving the throughput, and shortening the print time.

[0007]

As a first means for solving the above-mentioned problems, a paper feed mechanism of a printer according to the present invention includes a rotatable paper feed roller and a pressure contact with the paper feed roller. A driven roller that rotates following the rotation of the paper feed roller, a recording member that is conveyed while being held between the paper feed roller and the driven roller, and a recording head that prints a desired image on the recording member; A driving source for driving the paper feed roller to rotate, and in the rotation state of the paper feed roller, after slightly conveying the recording member to the downstream side by manual paper feed and rotation of the paper feed roller, A first paper feed operation for temporarily stopping the rotation of the roller, and after the first paper feed operation, the recording member is sent downstream by the rotation of the paper feed roller, and the printing start portion of the recording member is set to the recording start position. H In a second paper feed operation to send to,
The head of the recording member is configured to be located.

[0008] A second aspect for solving the above-mentioned problems is as follows.
The paper feed mechanism of the printer according to the present invention includes a gear portion formed between the paper feed roller and the drive source, an intermediate gear disposed between the paper feed roller and the drive source, and The rotation of the source is transmitted to the paper feed roller via the intermediate gear.

[0009] A third aspect for solving the above-mentioned problems is as follows.
The paper feed mechanism of the printer according to the present invention includes a paper detection member disposed upstream of the paper feed roller, and when the paper detection member detects that the recording member has been sent, the driving source By rotating the paper feed roller by
The first and second paper feeding operations are performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper feed mechanism of a printer according to the present invention will be described based on, for example, a thermal printer with reference to FIGS. Also, the same parts as those of the conventional parts will be described with the same symbols. First, the schematic configuration of the thermal printer shown in FIG. 1 is provided with a bottom plate 1 constituting a housing (not shown) made of a resin material or the like on a lower side, and made of flat rubber or the like on the upper portion of the bottom plate 1. The platen 2 is attached. Paper guides 3 and 4 are disposed on the left and right sides of the platen 2 in the drawing, respectively, and constitute a transport path H for transporting a recording sheet 8 described later. Above the transport path H, a head mounting member 5 is mounted on support pins 5a and 5b, and is disposed so as to be vertically movable. Also, the head mounting member 5
A recording head 6 composed of a thermal head or the like is attached above the platen 2 on the lower surface side of the recording head 6. On the left side of the recording head 6 in the figure, a sheet detecting member 7 composed of an optical sensor or the like for detecting that a recording member 8 described later has been sent to the transport path H is attached.

A recording member 8 made of thermal paper or the like is manually conveyed to the conveyance path H from the upstream side in the direction of arrow R. On the downstream side of the paper guide 4 in the transport path H, a paper feed roller 11 for transporting the fed recording member 8 to the downstream side is provided. The paper feed roller 11 has an outer peripheral portion made of rubber or the like, and as shown in FIG.
The gear portion 11b has a predetermined number of tooth ridges 11c formed on the outer peripheral portion. An intermediate gear 12 is disposed on the upper left side of the paper feed roller 11 shown in FIG. 2, and a gear portion 12 a having a plurality of tooth ridges is formed on an outer peripheral portion of the intermediate gear 12. The gear portion 11a of the paper feed roller 11 is in mesh with the gear portion 12a.

A drive source 13 composed of a motor or the like is disposed on the left side of the intermediate gear 12 in the figure. The rotation of the drive source 13 is controlled by the intermediate gear 1.
2 to the paper feed roller 11. Below the paper feed roller 11, there is provided a driven roller 14, which comes into pressure contact with the paper feed roller 11 and rotates according to the rotation of the paper feed roller 11. When the recording member 8 is manually fed to the paper feed roller 11 and the driven roller 14, the paper feed roller 11 rotates and the recording member 8 is moved between the paper feed roller 11 and the driven roller 14.
And can be transported downstream. The rotation torque of the paper feed roller 11 as described above is
Even if 4 is pressed, it rotates with low torque, so that the driving torque of the driving source 13 can be reduced.

The operation of locating the recording member 8 by the paper feeding mechanism of the printer according to the present invention having the above-described structure includes first and second operations.
In the first paper feeding operation, the recording member 8 is manually inserted into the conveyance path H in the direction of arrow R. Then, the leading end 8 a of the recording member 8 passes between the platen 2 and the recording head 6 via the lower part of the sheet detecting member 7 and contacts the outer peripheral portion of the paper feed roller 11. Then, the paper detecting member 7 detects the recording member 8 and turns ON,
By rotating the drive source 13, the intermediate gear 12 is rotated in the direction of arrow C, and the paper feed roller 11 is rotated in the direction of arrow D. By the rotation of the paper feed roller 11 in the direction of arrow D, the leading end 8a of the manually fed recording member 8 is held between the paper feed roller 11 and the driven roller 14. And
In the rotation state of the paper feed roller 11 in the direction of arrow D,
By manual feeding of the recording member 8 and rotation of the paper feed roller 11, the leading end 8a is slightly conveyed downstream of the paper feed roller 11 as shown in FIG. 2, and then the rotation of the paper feed roller 11 is temporarily stopped. Then, the first paper feeding operation ends. This first
Of the paper feed roller 11 meshed with the gear portion 12a of the intermediate gear 12 when the paper feed operation of FIG.
FIG. 3 shows a state in which backlash B2 has occurred on the right side wall of the tooth ridge 11c as shown in FIG. Although the driving source 13 is rotated to rotate the intermediate gear 12 in the direction of arrow C, the reason why the backlash B2 occurs on the right side wall of the tooth ridge 11c of the paper feed roller 11 is as follows. Even when the reference numeral 11 is in the idle state, the manual sheet feeding is continued, and the paper feed roller 1 is moved by the insertion force of the recording member 8 by the manual sheet feeding.
1 is applied in a direction indicated by an arrow D, and a backlash B2 as shown in FIG. 3 is generated.

After the first paper feeding operation, a second paper feeding operation is performed according to an instruction from a control member (not shown) inside the head mounting member 5. In the second paper feed operation, the recording member 8 is rotated by rotating the paper feed roller 8 in the same arrow D direction as the first paper feed operation in a state where the recording member 8 is released. In the operation shown in FIG. 4, the printing start portion (not shown) of the recording member 8 is sent to a position below the recording head 6 by an operation of feeding the printing material further downstream as shown in FIG.
The cue of the recording member 8 is performed. In this second paper feed operation, the force for rotating the paper feed roller 11 is only the intermediate gear 12, so that as shown in FIG.
Backlash B1 occurs on the left side wall of the tooth ridge 11c. After cueing the recording member 8 by the first and second paper feeding operations, the head mounting member 5 is lowered, the recording head 6 is moved to the platen 2 side, and the recording member 8 is moved between the recording head 6 and the platen 2. A desired image is printed on the recording member 8 by the recording head 6 while being pressed and held. Then, the paper feed roller 11 is rotated in the direction of arrow D to pull the recording member 8 after printing, discharge the recording member 8 downstream of the paper feed roller 11, and perform printing by the paper feed mechanism of the printer of the present invention. Ends.

The paper feed mechanism of the printer according to the present invention rotates the paper feed roller 11 in the same direction as the arrow D in both the first and second paper feed operations, and thereafter feeds the paper only in the direction of the arrow D. Since the roller 11 is rotated to print on the recording member 8, after the second operation, as shown in FIG. 5, the gear portion 12 a of the intermediate gear 12 always rotates the paper feed roller 11. Since the rotation of the drive source 13 is transmitted to the paper feed roller 11 in a state of being in contact with the right side wall of the tooth ridge 11c,
Even if there is a backlash B1 on the left side wall of the tooth ridge 11c,
The rotation of the paper feed roller 11 can be obtained without rotation unevenness, and the recording member 8 can be fed with a stable paper feed amount without paper feed unevenness. In the embodiment of the present invention, the thermal printer has been described as an example.
The paper feeding mechanism of the printer of the present invention is not limited to a thermal printer, but can be applied to other printers such as an ink jet printer.

[0016]

According to the paper feed mechanism of the printer of the present invention, when the paper feed roller is rotated, the recording member is slightly conveyed to the downstream side by the paper feed roller by manual paper feeding, and then the paper feed roller is rotated. A first paper feeding operation for temporarily stopping the printing, and after the first paper feeding operation, the recording member is sent downstream by rotation of the paper feeding roller, and a printing start portion of the recording member is sent to the recording head. With the second paper feed operation,
Since the cueing of the recording member is performed, the throughput can be increased by always rotating the drive source in the same direction and feeding the paper. In addition, the first and second paper feeding operations can perform stable paper feeding with no influence of backlash on print quality and without uneven feeding.
It is possible to provide a paper feed mechanism of a printer capable of obtaining high print quality.

Further, a gear portion is formed between the paper feed roller and the drive source, an intermediate gear is disposed between the transport roller and the drive source, and the rotation of the drive source is transmitted via the intermediate gear to the drive unit. Since the power is transmitted to the paper feed roller, the arrangement position of the drive source with respect to the paper feed roller is not limited, and the degree of freedom in design can be increased.

A sheet detecting member is provided upstream of the transport roller, and when the sheet detecting member detects that the recording sheet has been sent, the driving source rotates the sheet feed roller by the driving source. Since the first and second paper feeding operations are performed, the fed recording member can be reliably detected by the paper detection member, and when the recording member is sent to the paper feed roller. Thus, the paper feed roller can be surely rotated, and highly accurate paper feed is possible.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of a printer using a paper feeding mechanism of the printer of the present invention.

FIG. 2 is a side view of a main part illustrating a paper feeding mechanism of the printer according to the invention.

FIG. 3 is an enlarged view of a main part for explaining a paper feeding mechanism of the printer of the present invention.

FIG. 4 is a side view of an essential part for explaining a paper feeding mechanism of the printer of the present invention.

FIG. 5 is an enlarged view of a main part illustrating a paper feeding mechanism of the printer of the present invention.

FIG. 6 is a side view of a main part for explaining a paper feeding mechanism of a conventional printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom plate 2 Platen 3, 4 Paper guide 5 Head mounting member 5a, 5b Support pin 6 Recording head 7 Paper detection member 8 Recording member 8a Tip part 11 Paper feed roller 11a Rotating shaft 11b Gear part 11c Tooth tooth 12 Intermediate gear 13 Drive source 13a rotating shaft 13b drive gear 14 driven roller H transport path K paper feed mechanism

Claims (3)

[Claims] 1. A rotatable paper feed roller, a driven roller that comes into pressure contact with the paper feed roller and rotates following the rotation of the paper feed roller, and is held between the paper feed roller and the driven roller. A recording member that is conveyed and conveyed, a recording head that prints a desired image on the recording member, and a drive source that rotationally drives the paper feed roller. A first paper feed operation for temporarily stopping the rotation of the paper feed roller after a slight conveyance by the manual paper feed and the rotation of the paper feed roller, and the paper feed operation after the first paper feed operation. The recording member is sent to the downstream side by rotation of a roller, and a second paper feeding operation for sending a printing start portion of the recording member to the recording head is performed so as to perform cueing of the recording member. Printer Paper feed mechanism. 2. A gear portion is formed between the paper feed roller and the drive source, an intermediate gear is disposed between the paper feed roller and the drive source, and rotation of the drive source is controlled by the intermediate gear. 2. The paper feed mechanism of a printer according to claim 1, wherein the light is transmitted to the paper feed roller via a paper feed roller. 3. A paper detection member is provided upstream of the paper feed roller, and when the paper detection member detects that the recording member has been sent, the drive source rotates the paper feed roller. 3. The paper feeding mechanism according to claim 1, wherein the first and second paper feeding operations are performed.