JP2811829B2 - Printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention includes a pressing roller that presses a printing paper fed along a platen to a platen at a pressing position above a printing position. Printing device.

(Prior Art) Conventionally, a printing apparatus provided with a pressing roller starts a printing operation after setting a leading end of a printing paper in a state of being sandwiched between a pressing roller and a platen before starting a printing operation. It was like. In this case, there is a disadvantage that printing cannot be performed on the leading end of the printing paper corresponding to the distance from the printing position (the position of the print head) on the first line to the pressing position (the position of the pressing roller) thereabove.

In order to solve this, the present applicant has disclosed Japanese Patent Application Laid-Open No. 62-73971.
As shown in FIG. 8 (see FIG. 8), when the leading end of the printing paper 1 reaches the printing position (the position of the printing head 2), the printing operation is started, and by the subsequent line feed operation, the printing operation is started.
Reaches the holding position (the position of the pressing roller 3),
When the leading end of the printing paper 1 is put on the pressing roller 3, the pressing roller 3 is opened to a position shown by a two-dot chain line in FIG. 8, whereby the leading end of the printing paper 1 is shown by a two-dot chain line. As shown in the drawing, a printing apparatus has been developed in which the pressing roller 3 is closed and the leading end of the printing paper 1 is sandwiched between the platen 4 and the pressing roller 3 after passing through the platen 4 side.

(Problems to be Solved by the Invention) In the above configuration, in order to securely sandwich the leading end of the printing paper 1 between the platen 4 and the pressing roller 3, the paper feed amount (the leading end of the printing paper 1 rides on the pressing roller 3). Volume) must be set higher. This is because a non-negligible error occurs in the sheet feed amount due to a positioning error of the leading end of the sheet when the sheet is inserted or an error in the sheet feeding operation.

However, if the paper feed amount is set to a relatively large value, when a thick printing paper with a strong stiffness is used, or when the paper feed amount becomes too large due to a large error in the paper feed amount, even if the pressing roller 3 is opened, As shown in FIG. 9, a case occurs where the leading end of the printing paper 1 does not pass under the pressing roller 3 but simply bends and cannot be sandwiched between the platen 4 (hereinafter referred to as “miscatch”). .

The carriage 6 provided with the print head 2 is provided with a paper guide 7 for guiding the print paper 1 upward along the platen 4, but during a normal line feed operation,
The paper guide 7 is located below the pressing roller 3. In this state, the printing paper 1 is sent upward while being pressed against the platen 4 by the paper guide 7, so that the leading end of the printing paper 1 directly hits the lower part of the pressing roller 3, and There is a drawback that the paper guide 7 prevents the leading end of the paper from riding on the pressing roller 3, and the portion is easily wrinkled as shown in FIG.

The present invention has been made in view of such circumstances, and therefore, the object thereof is to make it possible to print from the leading edge of printing paper, and to reliably prevent miscatch,
It is an object of the present invention to provide a printing apparatus that can reliably pinch the leading edge of a printing sheet between a platen and a pressing roller and that can prevent the leading edge of the printing sheet from wrinkling.

[Structure of the Invention] (Means for Solving the Problems) The printing apparatus of the present invention provides a carriage provided with a print head, a paper guide opposed to a platen, and a print sheet sent out along the platen. In a printing apparatus including a pressing roller that presses the platen at a pressing position above a printing position, an opening and closing mechanism that opens and closes the pressing roller, and a control device that controls an operation and a printing operation of the opening and closing mechanism, The control device moves the carriage to a position where the paper guide is displaced laterally from below the pressing roller, before a line feed accompanying a printing operation before the leading end of the printing paper reaches the pressing position,
When the leading end of the printing paper is line feed forward to a position corresponding to the press position, the pressing roller is opened, and after the print paper reverse feeds back, after the line feed forward to the press position, , Wherein the press roller is closed to press the printing paper against the platen.

(Operation) When the leading edge of the printing paper reaches the printing position (the position of the print head), the printing operation is started. Thereafter, in a step before the leading end of the printing paper reaches the pressing position (the position of the pressing roller), the carriage is moved to a position where the paper guide is displaced laterally from below the pressing roller before the line feed accompanying the printing operation. Above, a line break. In this case, since the paper guide is line-feeded at a position deviated to the side from below the pressing roller, the printing paper is not pressed against the platen below the pressing roller by the paper guide.
This allows the print paper to be sent straight up in the tangential direction of the platen without being disturbed by the paper guide. I get to get on.

Then, when the leading end of the printing paper is line feeded forward to the position corresponding to the pressing position, the press roller is opened, the printing paper is fed back in reverse, and then the line feed is returned to the pressing position. In this case, when the pressing roller is opened, even if the leading end of the printing paper is merely bent without passing under the pressing roller to the platen side,
By performing a line feed in the reverse direction and a line feed in the forward direction, the leading end of the printing paper is reliably inserted between the platen and the pressing roller. Thereafter, if the pressing roller is closed, the leading end of the printing paper is reliably sandwiched between the pressing roller and the platen.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

First, as shown in FIG. 5, the platen 11 is rotatably supported between left and right side walls 12a and 12b of the main body frame 12 via a shaft 13. On the left end of the shaft 13 of the platen 11,
When the operation knob 14 is fitted and the user turns the operation knob 14, the platen 11 rotates together with the operation knob 14 and the printing paper 15
Is sent. A feed gear 16 is fitted to the right end of the shaft 13, and during a line feed operation, the rotational force of a paper feed step motor 17 (see FIG. 6) is transmitted to the feed gear 16 to rotate the platen 11. It is being moved.

A support shaft 18 and a guide rail 19 are provided in front of the platen 11 in parallel with the platen 11, and the carriage 20 is supported on the support shaft 18 and the guide rel 19 so as to be movable in the left-right direction. A print head 21 is provided on the carriage 20, and a predetermined gap is secured between the tip of the print head 21 and the platen 11. Further, the carriage 20 is provided with a printing paper 15 around the tip of the print head 21.
A paper guide 22 (see FIG. 2) for guiding the paper upward along the outer peripheral surface of the platen 11 is provided.

On the other hand, as shown in FIG.
A ribbon cassette 23 is detachably mounted, and a part of the print ribbon 24 accommodated therein is exposed to the outside, and is disposed in a gap between the tip of the print head 21 and the platen 11. During the printing operation, the carriage 20 is moved from the left to the right along the platen 11 by the rotation of the carriage driving motor 25 (see FIG. 6). Platen
It is printed on 11 printing papers 15.

A plurality of pressing rollers 26 are arranged to press the printing paper 15 against the platen 11 above the printing position. Each of these pressing rollers 26 is rotatably inserted into one shaft 27, and both left and right ends of the shaft 27 are supported by the main body frame 12 via arms 28a and 28b. Each arm 28a, 28b
As shown in FIGS. 2 to 4, the pressing roller is supported on the side walls 12a and 12b of the main body frame 12 via pins 29 so as to be rotatable in the front-rear direction, and the arms 28a and 28b are rotated. Two
6 is a closed position for pressing the printing paper 15 against the platen 11 (a position indicated by a solid line in FIGS. 3 and 4);
Can be moved (openable and closable) to and from an open position (a position shown by a two-dot chain line in FIGS. 3 and 4) where a gap is opened apart from the device.
It has become. Then, in order to regulate the amount of rotation of the arms 28a and 28b (the amount of movement of the pressing roller 26), each of the arms 28a and 28b
A stopper 30 protruding from the outer surface of b is inserted into a long hole 31 formed in the side walls 12a and 12b of the main body frame 12.

On the other hand, a locking projection 3 protruding from the upper end of each arm 28a, 28b
A tension spring 34 is stretched between 2 (see FIG. 2) and the locking projection 33 fixed below each arm 28a, 28b. In this case, each tension spring 34 and each arm 28
a and 28b constitute a toggle mechanism, and a tension spring 3
The position 4 is behind the neutral position L (the line connecting the locking projection 33 and the pin 29) shown by the dashed line in FIG. 3 (left side in FIG. 3).
The urging force of the tension spring 34 acts to urge the pressing roller 26 to the rear closed position (the position indicated by the solid line in FIG. 3). On the other hand, as shown in FIG. 4, the position of the tension spring 34 is
When moved to the left (in the left side of the figure), the urging force of the tension spring 34 acts to urge the pressing roller 26 to the front open position (the position indicated by the two-dot chain line in FIG. 4).

The opening / closing mechanism 39 that opens and closes the pressing roller 26 against the urging force of the tension spring 34 is configured as follows. That is, inside the lower ends of the arms 28a and 28b, bevel gears 36a and 36b that are rotatable in the front-rear direction around the pin 35 are provided, and the bevel gears 36a and 36b are provided at the lower ends of the arms 28a and 28b. The gears 37a and 37b are meshed. And
A pin 38 projects upward from each of the bevel gears 36a and 36b, and when the carriage 20 is moved to the right end, the carriage 20 comes into contact with the pin 38 of the right bevel gear 36b, and the bevel gear 36b
To the right, thereby moving the arms 28a, 28b to the second
The pressing roller 26 is opened by rotating in the direction of arrow A in FIGS. On the other hand, when the carriage 20 is moved to the left end, the carriage 20 comes into contact with the pin 38 of the left bevel gear 36a to rotate the bevel gear 36b to the left, thereby moving the arms 28a and 28b in FIG. Is pressed in the direction of arrow B to close the pressing roller 26.

The operation and printing operation of the opening / closing mechanism 39 configured as described above are controlled by a control device 40 (see FIG. 6) having a microcomputer (not shown) as described later.
The control device 40 receives an operation signal from a keyboard 41 and a detection signal from a paper detection unit 42 such as a photocoupler that detects the position of the leading end of the printing paper 15. As shown in FIG. 7, the paper detecting means 42 is arranged at a position close to and below the print head 21 so as to face the platen 11. In addition, below the platen 11,
Two paper feed rollers 43 and 44 are arranged, and the paper is fed between the two paper feed rollers 43 and 44 and the platen 11 with the print paper 15 interposed therebetween.

Thus, the control device 40 controls the operation of the opening / closing mechanism 39 and the printing operation according to the control program shown in FIG.
That is, the user sets the printing paper 15 and
By operating the print key (not shown), a paper suction instruction is given to the control device 40 (step S1). Thereafter, first, the carriage drive motor 25 is reversely rotated via the drive circuit 45, and the carriage 20 is retracted to, for example, the left end of the platen 11 (step S2). The reason for this is that the print head 21 or the like on the carriage 20 is retracted to the outside of the printing paper 15 so that the ink ribbon does not rub against the ink ribbon due to the elasticity of the paper leading to the outside when the paper is sucked. That's why. At this stage, the pressing roller 26 is a tension spring.
It is held in the closed position by the pulling force of 34.

After the carriage 20 is retracted, the paper feed step motor 17 is rotated forward through the drive circuit 46 to rotate the platen 11 forward, and the printing paper 15 is sucked (step S3). Thus, when the leading end of the printing paper 15 reaches the position facing the paper detecting means 42, it is detected by the paper detecting means 42, and a detection signal is input from the paper detecting means 42 to the control device 40 (step S4). ). Thereafter, the number of drive steps of the paper feed step motor 17 is counted (step S5),
When the count value reaches a predetermined value (step S6),
That is, when the leading end of the printing paper 15 reaches the printing position as shown in FIG. 7A, the printing operation is started (step S).
7). As a result, the print head 21 is driven via the drive circuit 47 while moving the carriage 20 from left to right along the platen 11, and printing is performed on the print paper 15. And 1
When the printing of the line is completed, a normal line feed command is issued (step S8). Based on this line feed command, first, the carriage 20
To the tip of the platen 11, for example (step S9),
The carriage 20 is moved to a position where the paper guide 22 is displaced laterally from below the pressing roller 26. Also at this stage, the pressing roller 26 is held in the closed position by the tensile force of the tension spring 34.

Then, after the carriage 20 retreats, the paper feed step motor 17 is rotated forward to rotate the platen 11 forward, and the line feeds forward (step S10). The operations of steps S7 to S10 are repeated until the leading end of the printing paper 15 reaches a position corresponding to the holding position as shown in FIG. 7B (step S11). In this case, whether or not the leading edge of the printing paper 15 has reached the position corresponding to the press position is determined in the same manner as described above, after the paper detecting means 42 detects the leading edge of the printing paper 15 and the subsequent paper feeding steps. The determination is made based on whether or not the count value of the number of drive steps of the motor 17 has reached a predetermined value.

Thereafter, as shown in FIG. 7 (b), when the leading end of the printing paper 15 is forward-returned to a position corresponding to the pressing position, the carriage driving motor 25 is rotated forward and the carriage 20 is rotated.
Is moved all the way to the right end of the platen 11. As a result, the carriage 20 comes into contact with the pin 38 of the right bevel gear 36b to rotate the bevel gear 36b rightward, thereby moving the arms 28a and 28b in the directions indicated by arrows A in FIGS. 2 and 4. To release the pressing roller 26 as shown in FIG. 7C (step S12). After this, the paper feed step motor 1
7 is rotated reversely to reverse line feed by one line (step S1
3). By this reverse line feed, the leading end of the printing paper 15 surely passes under the pressing roller 26 toward the platen 11 (the seventh line).
Figure (d). Then, after the reverse line feed, the paper feed step motor 17 is rotated in the normal direction, and the line feed is changed by one line (step
S14). As a result, as shown in FIG. 7 (e), the leading end of the printing paper 15 is fed to the pressing position and is inserted into the gap between the pressing roller 26 and the platen 11. After this,
The carriage drive motor 25 is rotated in the reverse direction to
20 is moved all the way to the left of platen 11. This allows
The carriage 20 contacts the pin 38 of the left bevel gear 36a to rotate the bevel gear 36b to the left, thereby rotating the arms 28a and 28b in the direction of arrow B in FIG. Is closed, and the leading end of the printing paper 15 is sandwiched between the pressing roller 26 and the platen 11 as shown in FIG. 7 (f) (step S15). Thereafter, a normal printing / normal line feed operation is performed (step S16).

According to the above embodiment, in a step before the leading end of the printing paper 15 reaches the pressing position, before the line feed following the printing operation, the carriage 20 is retracted and the paper guide 22 is moved laterally from below the pressing roller 26. After moving to the left end position of the platen 11 so as to separate, the line feed is made forward (steps S9 and S10), so that the paper guide 22 deviates from the width of the printing paper 15, and the printing paper 15 is It will not be pressed against the platen 11 side. As a result, the printing paper 15 is sent straight out in the tangential direction of the platen 11 without being disturbed by the paper guide 22, as shown in FIG. 7 (b).
26 does not come into direct contact with the lower part, and can smoothly ride on the pressing roller 26.
It is possible to reliably prevent the tip portion from being wrinkled.

In addition, when the leading end of the printing paper 15 is line feeded forward to a position corresponding to the pressing position, the pressing roller is opened, the printing paper is fed back in reverse, and then the line feed is returned to the pressing position. Therefore (steps S12 to S14), when the pressing roller is opened (step S12), it is assumed that the leading end of the printing paper 15 is merely bent without passing under the pressing roller 26 to the platen 11 side. Also, thereafter, by performing reverse line feed and forward line feed, the leading end of the printing paper 15 is reliably inserted between the platen 11 and the pressing roller 26, thereby reliably preventing miscatch,
The printing paper 15 can be reliably sandwiched between the leading end platen 11 and the pressing roller 26.

In the above-described embodiment, in step S9, the carriage 20 is moved to the left end of the platen 11 in order to move the paper guide 22 to a position laterally displaced from below the pressing roller 26. Not the paper guide
If the position of the carriage 22 is shifted to the side from below the pressing roller 26, the carriage 20 does not necessarily have to be moved to the end of the platen 11, and even in this case, the intended object of the present invention can be sufficiently achieved.

Further, in the above embodiment, the operation of the opening / closing mechanism 39 for opening / closing the pressing roller 26 is configured to be linked with the movement of the carriage 20, but the driving source of the opening / closing mechanism is configured by, for example, an electromagnetic solenoid. The pressure roller 26 may be configured to be opened and closed by the power cutoff.

In the above embodiment, in steps S13 and S14,
Normal line feed and reverse line feed are performed one line at a time.
The line may be broken forward or backward by two or more lines.
What is necessary is just to make the amount of forward line feed and reverse line feed equal.

Further, in the above embodiment, the paper detecting means 42 for detecting the leading end of the printing paper 15 is provided.
Paper feed step motor after detecting the tip of 15
Depending on the count value of the number of drive steps of 17, printing paper 15
It is determined whether or not the leading end of the print paper 15 has reached the printing position / pressing position.However, for example, the determination may be made based on the count value of the number of driving steps of the paper feed step motor 17 from the start of suction of the printing paper 15. You may do it.

In addition, the present invention can be modified in various ways, for example, a paper detection sensor for detecting whether the leading end of the printing paper 15 has reached the printing position or the holding position may be separately provided.

[Effects of the Invention] As is clear from the above description, the present invention provides a method in which the carriage and the paper guide are positioned below the pressing roller before the line feed following the printing operation before the leading end of the printing paper reaches the pressing position. Moving to the position where the printing paper is shifted toward the right side, and when the leading end of the printing paper is line feed forward to the position corresponding to the pressing position, the pressing roller is opened, and after the printing paper reverse line feed, After the line feed to the pressing position, the pressing roller is closed and the printing paper is pressed against the platen, so that the leading edge of the printing paper can be prevented from wrinkling, and the miscatch can be reliably prevented. As a result, the leading end of the printing paper can be reliably sandwiched between the platen and the pressing roller.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 7 show one embodiment of the present invention.
1 is a flowchart showing the flow of control, FIG. 2 is a perspective view of a main part, FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2, and FIG. 5 is a cross-sectional view taken along a line IV, FIG. 5 is a plan view of a peripheral portion of a platen, FIG. 6 is a block diagram showing an electrical schematic configuration, and FIGS. FIG. 5 is a vertical sectional left side view of a portion around a platen for performing the operation. 8 to 10 are longitudinal left side views showing different states for explaining the prior art. In the drawing, 11 is a platen, 15 is a printing paper, 20 is a carriage, 21 is a printing head, 22 is a paper guide, 24 is a printing ribbon, 26 is a pressing roller, 28a and 28b are arms, 34 is a tension spring, and 36 is a bulkhead. A gear, 39 is an opening / closing mechanism, 40 is a control device, and 42 is a sheet detecting means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 13/00-13/02 B41J 19/18

Claims (1)

(57) [Claims] A pressure roller for providing a paper guide opposed to a platen on a carriage provided with a print head, and pressing a print paper fed along the platen against the platen at a pressing position above a printing position. A printing device comprising: an opening and closing mechanism for opening and closing the pressing roller; and a control device for controlling the operation and printing operation of the opening and closing mechanism, wherein the control device causes the leading end of the printing paper to reach the pressing position. Before the line feed associated with the previous printing operation, the carriage is moved to a position where the paper guide is displaced laterally from below the pressing roller, and the leading end of the printing paper is line-feeded to a position corresponding to the pressing position. When the pressing roller is opened, the printing paper is reversed, the line is forwarded to the pressing position, and then the pressing is performed. Printing apparatus characterized by closed the over La is configured to press the said printing paper to said platen.