JPH10297790A - Paper conveyance method of printer and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey paper stably and enable the entry of head of paper securely by controlling in such a way that a paper feed roller rotates when a paper detection member detects a tip fringe of paper and inserting the tip fringe of paper into a contact part of the paper feed roller and an auxiliary roller without hitching the tip fringe of paper by the paper feed roller. SOLUTION: A drive motor is driven based on a control command from a control means to convey only one sheet of uppermost paper 2 in the direction of paper conveyance. When a paper detection sensor S detects a tip fringe of the paper 2 which is conveyed, a paper feed roller 13 begins to rotate in the direction of paper feed. Consequently, even if the tip fringe of the paper 2 knocks against a minute projection, it is securely inserted into a contact part of the paper feed roller 13 and an auxiliary roller 14 without being hitched in accordance with the rotation of the paper feed roller 13. Since the paper 2 whose tip fringe is brought in contact with the contact part is firmly gripped by the paper feed roller 13 on which the minute projection is formed and is conveyed in the direction of conveyance, precise entry of head becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport method and a paper transport device for a printer which transports paper in a printer.
The present invention relates to a paper transport method and a paper transport device for a printer capable of performing high-precision paper cueing.

[0002]

2. Description of the Related Art Generally, a thermal transfer printer, an output device such as a computer, a word processor, a facsimile, etc., is used.
Various printers such as page printers are used.

In such a printer, when desired recording is performed, a plurality of sheets are stored in a sheet mounting table provided in the printer body, and a sheet feed roller is brought into contact with the sheets to supply the sheets. By rotating the paper rollers, the paper stored in the paper mounting table is separated and fed one by one by a separation mechanism. The paper fed by the paper feed roller is conveyed toward a paper feed roller disposed before the recording position of the printer, and when the leading end of the paper in the paper conveyance direction reaches the paper feed roller, the paper feed roller moves the paper. , And then the sheet is conveyed by the rotation of the paper feed roller. A paper detection sensor, which is a paper detection member, is disposed at a predetermined interval on the upstream side in the paper transport direction with respect to the paper feed roller.

[0004] A recording section comprising a platen, a recording head, and the like is provided downstream of the paper feed roller, and paper is recorded and discharged by the recording section. The paper feed roller and the paper feed roller are rotatably driven by a drive motor via a transmission mechanism constituted by a predetermined gear group.

[0005] Incidentally, the paper feed roller often has a large number of minute projections formed on its surface. This is because the paper feed roller having such a structure can obtain a necessary gripping force by the minute projections on the surface biting into the paper, and can perform stable and accurate paper feed.

Next, a description will be given of a case where the cue of a sheet is performed in the printer.

The plurality of sheets stored in the sheet cassette are separated and conveyed one by one by a separation mechanism such as a separation claw by rotating the sheet supply roller. The leading edge of the conveyed sheet is further rotated by a predetermined amount from the time when the sheet is detected by the sheet detecting member, and
The sheet is brought into contact with the contact portion between the paper feed roller and the auxiliary roller. At this time, in the related art, since the paper feed roller is stopped without rotating, the abutted paper is bent. Then, using the reaction force (restoring force) of the bent portion of the sheet, the feeding direction of the sheet when the sheet is conveyed in an oblique state is corrected, and then the sheet feed roller is moved in the sheet feed direction. The paper has been conveyed to the recording start position by performing the fixed rotation, and cueing has been performed.

In other words, conventionally, the sheet is transported by adding a distance to the contact portion between the sheet feed roller and the auxiliary roller until the sheet comes into contact with the sheet. By controlling the rotation after a lapse of a certain time after the detection, the sheet is bent at the contact portion between the sheet feed roller and the auxiliary roller, thereby correcting the oblique insertion of the sheet.

[0009]

However, in the above-described cueing of the paper of the printer, when a predetermined amount of paper is conveyed after the leading edge of the paper is detected by the paper detecting member, as shown in FIG. In some cases, the leading edge of the paper is caught by a minute projection formed on the surface of the paper feed roller, and does not come into contact with the contact portion between the paper feed roller and the auxiliary roller.

In such a case, even if the paper feed roller is rotated, the paper is not conveyed by a predetermined amount. Specifically, the cue position of the paper is decremented, and the printing start position is shifted. There was a problem that desired recording could not be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a paper transport method and a paper transport apparatus for a printer which can transport paper stably and can reliably perform cueing of the paper. It is intended for.

[0012]

In order to achieve the above-mentioned object, a paper conveying method and apparatus of a printer according to the present invention is characterized in that the paper is conveyed in a conveying direction by a paper feed roller from a paper mounting portion and is conveyed. When the paper detecting member detects the leading edge of the paper to be fed, the paper feed roller is rotated in the paper transport direction, and the leading edge of the paper is transported to the contact portion between the paper feed roller and the auxiliary roller. Is rotated in the reverse direction so that the leading edge of the paper is located immediately before the contact portion, and then
The point is that the paper feed roller is again rotated by a predetermined amount in the paper transport direction to perform control so as to perform cueing of the paper.

By adopting such a configuration, when the leading edge of the paper is detected by the paper detecting member, the paper feed roller is controlled to rotate, so that the leading edge of the paper is caught by the paper feed roller. Can be inserted into the abutting portion between the paper feed roller and the auxiliary roller without any variation in minute cueing position of the paper, oblique insertion,
The paper feed roller is rotated in the reverse direction, and the leading edge of the paper sandwiched between the paper feed roller and the auxiliary roller is temporarily returned to a portion immediately before the contact portion in the paper transport direction, and the paper generated at this time is returned. The correction can be performed by making the leading edge of the sheet abut on the abutting portion by using the bending and aligning the leading edge with a position parallel to the paper feed roller. Therefore, even if a paper feed roller with fine protrusions formed on the surface is used,
Cueing of the sheet can be performed reliably.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 shows an embodiment of a printer to which a paper transport mechanism and a paper transport method of the present invention are applied. The printer 1 of the present embodiment is configured to convey paper 2 substantially horizontally to perform recording. The printer 1 has a printer frame 3 disposed inside a printer case (not shown). I have. Below the printer frame 3, a platen 4 having a flat plate shape and extending in the width direction of the printer frame 3 is disposed so that its recording surface is directed upward.

On one side of the printer frame 3, there is provided a carriage 5 which is reciprocally movable along a platen 4 by a drive mechanism (not shown). Thermal head 6 as a recording head in which a plurality of heating elements are arranged in a line
Are disposed so as to be able to freely contact and separate from the platen 4 by a drive mechanism (not shown). Further, the carriage 5 includes
A ribbon cassette 7 around which an ink ribbon of a desired color (not shown) is wound is detachably mounted. The ink ribbon is disposed between the heating element portion of the thermal head 6 and the platen 4. It is made to be guided to. Then, with the paper 2 and the ink ribbon being supplied between the platen 4 and the thermal head 6, the thermal head 6 is pressed against the platen 4, and the thermal head 6 in the head down state and the platen 4 are pressed. The position is the recording position.

A sheet table 8 as an example of a sheet table is disposed below the printer frame 3 on the upstream side in the sheet conveying direction. A plurality of sheets 8 are provided on the upper surface of the sheet table 8. The sheets 2 are stacked and placed.
A plurality of friction pads (not shown) made of a material such as cork are embedded on the upper surface of the paper mounting table 8 so that the surfaces thereof are flush with the paper mounting table 8. A separating plate 9 is provided at the leading end of the sheet 2 to contact the leading edge of the sheet 2 and to separate only the uppermost sheet 2 of the stacked sheets 2.

A paper feed roller drive shaft 10 extending in the width direction of the printer frame 3 and having both ends supported on both sides of the printer frame 3 is provided above the paper mounting table 8.

At the position of the paper feed roller drive shaft 10 corresponding to the friction pad of the paper mounting table 8, the sectional shape is substantially D.
A plurality of feed rollers 11 having a U-shape are attached at predetermined intervals in the axial direction, and the feed roller drive shaft 10 is mounted on the paper mounting table 8 by an urging member such as a torsion coil spring (not shown). Biased in the direction.

The paper feed roller drive shaft 10 of the paper feed roller 11 is swingable about a support shaft (not shown) formed on the printer frame 3 by a support shaft and a connection arm (not shown).

On the upstream side of the printer frame 3 with respect to the platen 4 in the paper transport direction, a paper feed roller drive extending in the width direction of the printer frame 3 and having both ends supported on both sides of the printer frame 3 is provided. A shaft 12 is provided, and a plurality of paper feed rollers 13 are attached to the paper feed roller drive shaft 12 at predetermined intervals.
Above each paper feed roller 13, an auxiliary roller 14 which is in contact with the outer peripheral surface of the paper feed roller 13 and is rotated by the paper feed roller 13 is rotatably disposed.

A paper feed roller 11 is provided between the paper mounting table 8 of the printer frame 3 and the paper feed roller 13.
A guide plate 15 for guiding the paper 2 taken out of the paper mounting table 8 between the paper feed roller 13 and the auxiliary roller 14 is provided. A paper detection sensor S is provided as a paper detection member that swings when the paper 2 is conveyed to the fifteen portions and detects the paper 2. As the sheet detection sensor S, a micro switch, a reflection type optical sensor, or the like can be used.

The platen 4 of the printer frame 3
The printer frame 3 is located further downstream in the paper transport direction.
A paper discharge roller drive shaft 16 extending in the width direction of the printer and supported by the printer frame 3 is rotatably disposed. The paper discharge roller drive shaft 16 discharges the paper 2 on which recording has been completed to the outside. A plurality of discharge rollers 17 are attached at predetermined intervals.

Further, the paper feed roller 11 is
Is fed by the guide plate 15 before the recording position, is transferred to the paper feed roller 13 and the auxiliary roller 14, and is sandwiched between the paper feed roller 13 and the auxiliary roller 14. The paper 2 after recording is conveyed to a recording position, and is discharged outside the printer 1 by a discharge roller 17.

In the present embodiment, it is assumed that a large number of minute projections are formed on the surface of the paper feed roller 13 for gripping the abutted paper as in the conventional case.

The drive mechanism for the paper feed roller 11, paper feed roller 13, and paper discharge roller 17 is provided via an output shaft of a drive motor 18 such as a stepping motor and a plurality of gears (hereinafter referred to as a gear group). Each roller 11, 1
The drive shafts 10, 12, and 16 of the paper feed rollers 3 and 17 are connected to each other.
The paper feed roller 13 is rotatable in both the transport direction of the paper 2 and the reverse direction.

Control means 19 is electrically connected to the drive motor 18, and the drive motor 18
The rotation driving direction, the rotation amount, and the like are controlled based on a control command output from the control unit 19. The control means 19 controls the operation of each part of the printer 1 and, as shown in FIG. 2, comprises a CPU 20, a memory 21 having a predetermined capacity of ROM, RAM and the like, and a controller 22. Further, the control unit 19 also functions as a control unit of the sheet conveying device in the present invention.

In the memory 21 of the control means 19, the drive motor 18, the paper feed roller 11, the paper feed roller 13,
A program for driving and controlling the holding means and the like is stored. Then, according to this program, the sheet detection sensor S serving as the sheet detection member
When the leading edge of the paper 2 fed by the printer 2 is detected, the rotation of the paper feed roller 13 in the transporting direction of the paper is started, and the paper feed roller 11 is further rotated by a predetermined amount, so that the leading edge of the paper 2 is Is inserted between the paper feed roller 13 and the auxiliary roller 14, and thereafter, only the paper feed roller 13 is driven to rotate in a direction opposite to the paper conveyance direction, and once the leading edge of the paper 2 is After the contact portion between the feed roller 13 and the auxiliary roller 14 is positioned immediately before in the sheet conveyance direction, the paper feed roller 11 and the paper feed roller 13 are driven to rotate in the forward direction again, and the head of the sheet 2 is moved. It is designed to take out.

Next, the operation of this embodiment having the above-described configuration will be described with reference to the flowchart shown in FIG.

In the printer 1 according to the present embodiment,
When performing a recording operation for recording on paper 2, first,
In step ST1, a predetermined initialization operation is performed by turning on the power of the printer 1 or inputting a print start command to the control unit 19.

Next, in step ST2, the sheet detection sensor S detects whether or not the sheet 2 is present in the vicinity of the sheet feed roller 13. If the sheet 2 is present, the process proceeds to step ST10, where the sheet 2 is detected. Is discharged.

On the other hand, if the sheet 2 does not exist, the process proceeds to the next step ST3, where the sheet 2 is fed. In the present embodiment, as shown in FIG. 4, by driving a drive motor 18 in accordance with a control command from a control unit 19, the driving force is applied to the paper feed roller 11 via the gear group to thereby In the direction in which the sheet 2 can be conveyed, and swing the sheet feed roller drive shaft 10 downward to move the sheet feed roller 11 to the sheet placing table 8.
To the upper surface of the paper 2 stacked on the sheet. Then, the rotation of the paper feed roller 11 conveys only the uppermost sheet 2 in the sheet conveyance direction. In this case, since the separation plate 9 is arranged on the sheet mounting table 8, the separation plate 9 applies a load to the leading edge of the sheet 2, and only the uppermost sheet 2 is separated. It can be transported smoothly.

When the paper 2 is fed in this way, in step ST4, the presence or absence of the paper 2 is detected by the paper detection sensor S, and the paper 2 is detected by the paper detection sensor S.
If it is not detected that the sheet 2 is present, it is determined that the sheet 2 is not present on the sheet table 8 or the sheet 2 is not properly fed, and the process proceeds to step ST5 to stop the sheet feeding. .

On the other hand, when the presence of the paper 2 is detected by the paper detection sensor S, the control means 19
It is determined that the paper 2 has been properly fed, and the process proceeds to step ST6, in which the drive motor 18 is rotated by a predetermined number of steps to rotate the paper feed roller 11 in the transport direction of the paper 2. Then, the control is performed so that the paper feeding operation is continued, and the rotation of the paper feed roller 13 in the transport direction of the paper is started.

Then, in step ST6, FIG.
As shown in FIG. 4, by continuing to drive the drive motor 18, the paper feed roller 13 and the paper feed roller 11 are rotated clockwise in FIG. At this time, since the paper feed roller 13 is rotated in the transport direction of the paper 2, it is assumed that the leading edge of the paper 2 comes into contact with the minute protrusion formed on the surface of the paper feed roller 13. The paper 2 is also fed to the contact portion between the paper feed roller 13 and the auxiliary roller 14 according to the rotation of the paper feed roller 13 without the conveyance of the paper 2 being hindered.

Next, in step ST7, the paper feed roller 13 holding the leading end of the paper at the contact portion with the auxiliary roller 14 and the drive motor 18
Is controlled by the control means 19 so that only a predetermined number of steps of rotation is driven in the reverse direction.

At this time, the sheet 2 is conveyed in the reverse direction, so that the contact portion between the sheet feed roller 13 and the auxiliary roller 14 in the sheet conveying direction and the sheet feed roller contacting the sheet 2 As shown in FIG. 5, the sheet 11 is located in a state where the extra conveyed sheet length is deflected. At this time, the leading edge of the paper 2 is brought into contact with the abutting portion by its own reaction force (restoring force), and the paper 2 is aligned so as to be parallel to the paper feed roller 13 so as to be printed. Attitude control for the delivery is performed. That is, when the sheet conveyed obliquely at the time of the supply is disengaged from the contact portion between the paper feed roller 13 and the auxiliary roller 14 due to the reverse conveyance of the paper feed roller 13 described above, its leading edge is set to the paper feed roller 13. Are aligned so that they are parallel to each other.

Next, in step ST8, as shown in FIG. 6, the drive motor 18 is driven at the timing when the leading edge of the paper 2 is aligned in parallel with the contact portion between the paper feed roller 13 and the auxiliary roller 14. The paper feed roller 1
3 and the paper feed roller 11 are rotated by the number of steps corresponding to the cue amount in the paper transport direction. As a result, the paper 2 aligned just before the contact portion with its leading edge along the paper feed roller 13 is directed between the platen 4 and the thermal head 6 located downstream in the paper transport direction. Predetermined amount,
The sheet is conveyed, and the sheet is searched for.

That is, by the rotation of the paper feed roller,
The sheet aligned with its leading edge abutting on the abutting portion is reliably conveyed while being sandwiched between the paper feed roller and the auxiliary roller. Therefore, by controlling the amount of rotation of the paper feed roller from this point, accurate cueing can be performed.

It should be noted that the printer used in this embodiment is configured so that the contact of the paper feed roller 11 with the paper 2 is released when the cueing of the paper 2 is completed. I do.

From this state, in step ST9,
Predetermined recording is started. That is, the thermal head 6
Is pressed against the platen 4 via the ink ribbon and the paper 2 to move the carriage 5 along the platen 4 while selectively driving the heating elements of the thermal head 6 based on a desired recording signal. The desired recording is performed on the paper 2.

When the paper 2 is transported,
By driving the drive motor 18, the paper feed roller 13
By rotating in the transport direction. Thereafter, the paper feed roller 13 repeats the paper feed accompanying the line feed operation required for recording.

When the recording on the sheet 2 is completed, step S
At T10, the paper 2 is discharged by driving the drive motor 18 as it is and rotating the discharge roller 17.

Next, in step ST11, the presence or absence of the sheet 2 is detected by the sheet detection sensor S. When the sheet 2 is properly conveyed and the sheet detection sensor S no longer detects the sheet 2, the process proceeds to the next step ST12. However, if the sheet 2 is still detected by the sheet detection sensor S even after the sheet 2 is discharged, the process proceeds to step ST13 to stop the sheet discharging operation.

Thereafter, in step ST12, the sheet 2 is discharged, and the recording operation on one sheet 2 is completed.

When printing is to be performed on the next sheet 2, the process returns to step ST3, and the above operation is repeated to sequentially record on the sheet 2.

As described above, according to the sheet conveying method and the sheet conveying apparatus of the present embodiment, when the sheet detecting sensor 20 detects the leading edge of the conveyed sheet 2, the sheet feeding roller 13 moves in the sheet feeding direction. Since the rotation of the paper feed roller 13 is started, even if the leading edge of the paper 2 collides with the minute projection, the paper feed roller 1 is surely prevented from being caught by the rotation of the paper feed roller 13.
3 and the auxiliary roller 14 can be inserted into the contact portion. Then, after that, the paper feed roller 13 is rotated in the reverse direction to reversely convey the paper 2, the leading edge of the paper 2 is positioned immediately before the contact portion, and the paper 2 is moved to the contact portion with the contact portion. The sheet 2 is bent between the sheet feeding roller 11 and the sheet 2.
By using the reaction force of the paper 2 to make the leading edge of the paper 2 abut on the abutting portion between the paper feed roller 13 and the auxiliary roller 14, the oblique insertion of the paper 2 can be corrected. Further, the paper 2 whose leading edge is in contact with the abutting portion is provided on the paper feed roller 13 on which minute projections are formed.
The paper 2 is securely gripped and is securely transported in the transport direction. Therefore, by controlling the rotation amount of the paper feed roller 13 from the time when the reverse transport of the paper 2 is completed, the amount of cueing may be negative. And it is possible to perform accurate cueing.

The present invention is not limited to the above-described embodiment, but can be variously modified as needed.

[0049]

As described above, according to the sheet conveying method and the sheet conveying apparatus according to the present invention, the desired recording is obtained by correcting the oblique insertion of the sheet and performing the accurate cueing of the sheet. The effect that can be performed can be produced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a reference state in an embodiment of a paper transport mechanism of a printer to which a paper transport apparatus according to the present invention is applied;

FIG. 2 is a block diagram showing a control unit of a paper transport mechanism of a printer to which the paper transport device of the embodiment is applied.

FIG. 3 is a flowchart illustrating the operation of the paper transport mechanism according to the embodiment.

FIG. 4 is a vertical cross-sectional view illustrating a sheet conveyance state according to the embodiment.

FIG. 5 is a vertical cross-sectional view showing a state immediately before conveyance of the sheet cueing is performed.

FIG. 6 is a vertical cross-sectional view illustrating a sheet conveyance state in the embodiment.

FIG. 7 is a vertical cross-sectional view showing a state immediately before carrying out conventional cueing of paper;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Paper 3 Printer frame 4 Platen 5 Carriage 6 Thermal head 7 Ribbon cassette 8 Paper mounting table 9 Separation plate 10 Feed roller shaft 11 Feed roller 12 Paper feed roller drive shaft 13 Paper feed roller 14 Auxiliary roller 15 Guide plate 16 Discharge roller drive shaft 17 Discharge roller 18 Motor 19 Control means 20 CPU 21 Memory 22 Controller

Claims (4)

[Claims] A paper feed roller capable of abutting against paper stored in a paper mounting portion and separating and feeding the paper one by one; A paper feed roller that conveys to a recording position, an auxiliary roller that is arranged to be able to contact the paper feed roller, and a paper detection provided in a paper conveyance path between the paper feed roller and the paper feed roller And a drive motor for driving the paper feed roller and the paper feed roller. The drive motor drives the paper feed roller and the paper feed roller so that the paper feed roller is rotated and accommodated in the paper tray. A paper transport method of a printer for transporting a paper to a predetermined recording position, wherein the paper is transported in a transport direction from a paper loading unit by a paper feed roller, and the leading edge of the transported paper is detected by the paper detection. When a member is detected At this point, the paper feed roller is rotated in the paper transport direction, and after the leading edge of the paper is transported to the contact portion between the paper transport roller and the auxiliary roller, the paper transport roller is rotated in the reverse direction to rotate the paper. The printer is characterized in that the leading edge is positioned immediately before the contact portion, and thereafter, the paper feed roller is rotated again by a predetermined amount in the paper transport direction to perform the cueing of the paper. Paper transport method. 2. The method according to claim 1, wherein a plurality of minute projections are formed on a surface of the paper feed roller. 3. A paper feed roller capable of coming into contact with the paper stored in the paper mounting portion, separating the paper one by one and feeding the paper, and feeding the paper fed by the paper feed roller. A paper feed roller that conveys to a recording position, an auxiliary roller that is arranged to be able to contact the paper feed roller, and a paper detection provided in a paper conveyance path between the paper feed roller and the paper feed roller And a drive motor for driving the paper feed roller and the paper feed roller. The drive motor drives the paper feed roller and the paper feed roller so that the paper feed roller is rotated and accommodated in the paper tray. A paper transport device of a printer for transporting a paper to a predetermined recording position, wherein the paper is transported in a transport direction from a paper loading unit by a paper feed roller, and the leading edge of the transported paper is detected by the paper detection. When a member is detected At this point, the paper feed roller is rotated in the paper transport direction, and after the leading edge of the paper is transported to the contact portion between the paper transport roller and the auxiliary roller, the paper transport roller is rotated in the reverse direction to rotate the paper. A control unit is provided that controls the front edge to be located immediately before the contact portion, and then controls the paper feed roller to rotate again by a predetermined amount in the paper conveyance direction to perform cueing of the paper. Paper transport device of the printer. 4. The paper transport device according to claim 3, wherein a number of minute projections are formed on a surface of the paper feed roller.