JPH03161369A - Printing device - Google Patents

Abstract

PURPOSE:To prevent the tip of printing paper from becoming crimped and caught erroneously and ensure the positive catching of the tip of the paper between platen pressing rollers by controlling the positions of the paper, a carriage and the pressing roller so that these positions are moved as specified. CONSTITUTION:Prior to a normal line feed accompanied by a printing action before the tip of printing paper 15 reaches a holding position, a carriage 20 is moved to a position where a paper guide 22 is offset to the side from below a pressing roller 26. Then when the tip of the paper 15 is set to a position corresponding to the holding position in the forward line feed mode, the paper 15 is reset in the backward line feed mode by setting the pressing roller 26 to a released state. After that, the paper 15 is set back to the holding position in the forward line feed mode, and the pressing roller 26 is closed to press the paper 15 against a platen 11. Subsequently, the tip of the paper is prevented from becoming crimped and at the same time, from failing to be caught correctly. In addition, the positive holding of the paper 15 between the platen 11 and the pressing roller 26 is ensured.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention provides a method for printing paper fed along a platen.
The present invention relates to a printing device equipped with an immediate pressure roller that presses against a platen at a holding position above the printing position.

(Prior Art) Conventionally, in a printing device equipped with a pressure roller, before starting a printing operation, the leading edge of printing paper is set between a suppression roller and a platen, and then the printing operation is started. It was like that. In this case, there is a drawback that printing cannot be performed on the leading edge of the printing paper corresponding to the distance from the printing position (print head position) of the first line to the presser position (pressing roller position) above it.

In order to solve this problem, the applicant has proposed
As shown in Publication No. 71 (see Figure 8), when the leading edge of the printing paper 1 reaches the printing position (the position of the print head 2), the printing operation starts, and the subsequent changeover action causes the printing paper 1 to When the leading edge of the printing paper 1 reaches the pressing position (the position of the pressing roller 3) and the leading edge of the printing paper 1 rides on the pressing roller 3, the jll If roller 3 is indicated by the two-dot highlighted line in FIG. After opening the printing paper 1 to the position shown in FIG. We are developing a printing device that can be inserted between the

(Problem to be Solved by the Invention) In the above structure, in order to sandwich the leading edge of the printing paper 1 between the platen 4 and the pressing roller 3 with an accurate length, the paper feed amount (the leading edge of the printing paper 1 must be pressed (amount that rides on roller 3)
It is necessary to set a large number of . This is because it is impossible to keep track of the paper feed amount due to errors in positioning the leading edge of the paper when inserting the paper and errors in the paper feed operation. This is because a t difference occurs.

However, if the paper feed amount is set too high, if stiff and thick printing paper is used, or if the error in the paper feed amount is large and the paper feed amount becomes excessive, even if the pressure roller 3 is released, As shown in Figure 9, printing paper 1
A case may occur in which the leading end of the pressing roller 3 simply challenges the pressing roller 3 without passing under it, but cannot be caught between the pressing roller 3 and the platen 4 (hereinafter referred to as "miscatch").

Further, 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. is located below the suppression roller 3. In this state, the printing paper 1 is sent upward while being pressed against the platen 4 side by the paper guide 7, so the leading edge of the printing paper 1 directly hits the lower part of the pressure roller 3, and the printing paper The paper guide 7 prevents the leading edge of the paper from riding on the suppression roller 3.
There was a drawback that this part was easily wrinkled as shown in Figure 10 of the table.

The present invention was made in consideration of these circumstances, and its purpose is to reliably prevent miscatch in a device that enables printing from the leading edge of printing paper, and to ensure that the leading edge of the printing paper is connected to the platen. It is an object of the present invention to provide a printing device which can be reliably inserted between a pressing roller and which can prevent the leading edge of printing paper from being wrinkled.

[Structure of the Invention] (Means for Solving the Problems) A printing device of the present invention includes a carriage provided with a print head and a paper guide positioned opposite to a platen, and print paper fed out along the platen. A printing device equipped with a pressure roller pressed against the platen at a presser position above the printing position, comprising an opening/closing mechanism for opening and closing the pressing roller, and a control device for controlling the operation of the opening/closing mechanism and the printing operation, The control device moves the carriage to a position where the paper guide comes off to the side from below the first pressing roller before a normal line break accompanying a printing operation before the leading edge of the printing paper reaches the presser position; When the leading edge of the printing paper has been subjected to a normal line feed to a position corresponding to the presser position and χ·l, the pressing roller is opened and the printing paper is reversely line-feeded, and then a normal line feed is carried out to the presser position. The printing paper is characterized in that the printing paper is pressed against the platen by closing the pressing roller.

(Function) When the leading edge of the printing paper reaches the printing position (position of the print head), the printing operation is started. After this, in the step before the leading edge of the printing paper reaches the holding position (position of the pressure roller), the carriage is moved to a position where the paper guide comes off to the side from below the pressure roller before the normal line feed associated with the printing operation. Make a line break above. In this case, the normal line feed is performed at a position where the paper guide is deviated from below the suppression roller to the side.
Below the suppression roller, the printing paper is no longer pressed against the platen by the paper guide. As a result, the print paper is fed straight up in the tangential direction of the platen without being obstructed by the paper guide, so the leading edge of the print paper no longer hits the lower part of the pressure roller, allowing it to smoothly reach the suppression roller. I'll get on it.)

Then, when the leading edge of the printing paper is line-feeded normally to a position corresponding to the presser position, the suppression roller is opened, the printing paper is line-feeded backwards, and then the line is line-feeded normally to the presser position. In this case, when the immediate pressure roller is released, even if the leading edge of the printing paper simply bends without passing under the pressure roller toward the platen, it will then perform a reverse line feed and a normal line feed. This will cause the leading edge of the printing paper to catch fire between the platen and the suppression roller. Ii people will be. Thereafter, when the pusher roller is closed, the leading edge of the printing paper is precisely caught between the pusher roller and the platen.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 7.

First, as shown in FIG. 5, the platen 11 is rotatably supported via a shaft 13 between the left and right side walls 12a and 12b of the main body frame 12. As shown in FIG. Axis 1 of this platen 11
An operating knob 14 is fitted to the left end of the platen 11, and when the user turns the operating knob 14, the platen 11
rotates to feed the printing paper 15.

Further, a feed gear 16 is fitted to the right end of this shaft 13, and the feed gear 16 is fitted to the right end of this shaft 13, and the feed gear 16 is fitted to the right end of this shaft 13, and the feed gear 16 is fitted to the right end of this shaft 13, and the feed gear 16 is fitted to the right end of this shaft 13. 1, the rotational force of a paper feeding step motor 17 (see FIG. 6) is transmitted to this feeding gear 16 to rotate the platen 11.

A support shaft 18 and one guide rail are provided on the front side of the platen 11 in parallel thereto.
8 and a guide rail 19, a carriage 20 is supported movably in the left stone direction.

A print head 21 is provided on this carriage 20,
A predetermined gap is secured between the tip of the print head 21 and the platen 11. Historically, in Carriage 20,
The print paper 15 is placed around the tip of the print head 21.
A paper guide 22 (see FIG. 2) is provided to guide the paper upward along the outer peripheral surface of the platen 11.

On the other hand, as shown in FIG. 5, on the main body frame 12,
The ribbon cassette 23 is removably attached, and a part of the printing ribbon 24 housed therein is exposed to the outside.
It is arranged in the gap between the tip of the print head 21 and the platen 11. During the printing operation, the carriage 20 is moved from left to right along the platen 11 by the rotation of the carriage drive motor 25 (see FIG. 6), and the print head 21 moves the carriage 20 through the exposed portion of the printing ribbon 24. The image is printed on the printing paper 15 on the platen 11.

Then, the printing paper 15 is placed on the platen 11 above the printing position.
A plurality of pressure rollers 26 are arranged to press the surface. Each of these pressing rollers 26 rotates on one shaft 27? 'l:, and both left and right ends of the leg 27 are supported by the main body frame 12 via arms '2sa and 28b. Each arm 23a, 28b is
As shown in the figure, it is rotatably supported in the front-rear direction by the side walls 12a and 12b of the main body frame 12 via a fin 29,
Due to the simultaneous movement of the arms 28a and 28b, the suppression roller 2
6 presses the printing paper 15 against the platen 1] in the closed position (the position shown by the solid line in FIGS. 3 and 4), and in the open position where it is separated from the platen 11 and opens the display (the position shown in FIGS. 3 and 4). It is movable (can be opened and closed) between the two points (the position indicated by the two-dot chain line in the figure). In order to restrict rotation of the arms 28a, 28b (movement ffi of the pressing roller 26), a stopper 30 protruding from the outer surface of each arm 28a, 28b or a stopper 30 mounted on the side wall 12a, 12b of the main body frame 12 is provided. It is inserted into the elongated hole 31.

On the other hand, a tension spring 34 is provided between a locking projection 32 (see FIG. 2) protruding from the upper end of each arm 28a, 28b and a locking projection 33 fixed below each arm 2ga, 28b. ■ has been handed over. In this case, each tension spring 34 and each arm 28a, 28b constitute a toggle mechanism, and the tension spring 34 is positioned at a neutral position L (which connects the locking protrusion 33 and pin 29) as shown by the dashed line in FIG. When the pressure roller 26 is moved backward (to the left in FIG. 3) beyond the line), the biasing force of the tension spring 34 urges the pressure roller 26 to the rear closed position (the position shown by the solid line in FIG. 3). It works like this. On the other hand, as shown in FIG.
When the position No. 4 is moved forward beyond the neutral position L (direction k in Fig. 4), the biasing force of the spring 34 moves the suppression roller 26 to the forward open position (two-point parallel line to the fourth prisoner). (position shown).

The opening/closing machine side 39 that opens and closes the suppressing roller 26 against the biasing force of the temporary spring 34 is constructed as follows. That is, bevel gears 36a, 36b are provided inside the lower ends of each of the arms 28a, 28b, and are movable in the front and rear directions around the pin 35.
6b is engaged with a gear 37a37b formed at the lower end of each arm 28a, 28b. And each Kasayutun 3
6a and 36b are provided with pins 38 that protrude upward, and when the carriage 20 is moved to the right end, the carriage 20 comes into contact with the bin 38 of the right side, which causes the scratched gear 36b. −1 movement to the right, thereby causing arm 28a. 28b is rotated in the direction of arrow A in FIGS. 2 and 4 to explain the presser roller 26. On the other hand, when the carriage 20 is moved to the k end, the carriage 20
0 comes into contact with the pin 38 of the bevel gear 36a on the k side and rotates the bevel gear 36b to the left, thereby rotating the arms 28a and 28b in the direction of arrow B in FIG. Close roller 26.

The operation of the opening/closing mechanism 39 constructed in this way and the printing operation are controlled as described later by a control device 40 (see FIG. 6) equipped with a microcomputer (not shown).

The control device 40 receives an operation signal from a keyboard 41 and also receives a detection signal from a paper detecting means 42 of a photocoupler e that detects the position of the tip of the printing pad 15. As shown in FIG. 7, the sheet detecting means 42 is disposed at a position close to the bottom of the mark ahead 21 so as to face the platen 11 in the .chi.1 direction. Note that below the platen 11 there are two paper feed rollers 43, 44.
are arranged, and the print paper 15 is sandwiched between these paper feed rollers 4344 and the platen 11 to feed the paper.

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, when the operator sets the print paper 15 and operates a print key (not shown) on the keyboard 41, a paper suction command is given to the control device 40 (step Sl). Thereafter, first, the carriage drive motor 25 is reversely rotated via the drive circuit 45, and the carriage 20 is retracted, for example, to the left end of the platen 11 (step S2). The reason for doing this is to retract the print head 21 etc. on the carriage 20 to the outside of the print paper 15 so that the ink ribbon is not rubbed by the elasticity of the paper leading edge trying to spread outward when the paper is sucked. It's for a reason. At this stage, the pressure roller 26 is held in the closed position by the tensile force of the tension spring 34.

After the carriage 20 is retracted, the paper feeding step motor 17 is rotated in the normal direction via the drive circuit 46 to rotate the platen 11 in the normal direction, and the printed Jl paper 15 is sucked (step S3). As a result, when the leading edge of the printing paper 15 reaches the position facing the paper detection means 42, it is detected by the paper detection means 42, and a detection signal is manually inputted from the paper detection means 42 to the control device 40 (step S4). Thereafter, the number of driving steps of the paper feeding step motor 17 is counted (step S5), and the specific point when the count value reaches a predetermined value (step S6), that is, the number of driving steps of the paper feeding step motor 17 is When the leading edge of the printer reaches the printing position, the printing operation is started (step S7). This results in
While moving the carriage 20 from left to right along the platen 11, the print head 21 is driven via the drive circuit 47 to print on the print paper 15. Then, when printing of one line is completed, a normal line feed command is issued (step S8).
. Based on this line feed command, the carriage 20 is first retracted to the left end of the platen 11 (step S9),
The carriage 20 is moved to a position where the paper guide 22 is removed laterally from below the suppression roller 26. Even at this stage, the pressure roller 26 is held in the closed position by the tensile force of the tension spring 34.

After the carriage 20 is evacuated, the paper feeding step motor 17 is rotated forward and the platen 11 is rotated forward and backward.
．． A new line is added (step 810). Above steps 87~
The operation in S10 is repeated until the leading edge of the printing paper 15 reaches a position corresponding to the presser foot position as shown in FIG. 7(b) (step S11). In this case, the judgment as to whether or not the leading edge of the printing paper 15 has reached the position corresponding to the presser foot position is made after the paper detection means 42 detects the leading edge of the printing paper 15, as described above. ``I'l1'' is disconnected depending on whether the count value of the drive step number of the step motor 17 has reached a predetermined value.

Thereafter, as shown in FIG. 7(b), when the leading edge of the printing paper 15 has been correctly line-feeded to the position corresponding to the presser foot position, the carriage drive motor 25 is rotated in the normal direction to move the carriage 20 to the right end of the platen 11. Move it all the way. This causes the carriage 20 to come into contact with the pin 38 of the right bevel gear 36b and rotate the bevel gear 36b to the right, thereby causing the arms 28a and 28b to move as shown in FIGS.
The pressure roller 26 is rotated in the direction of arrow A in the figure to release the pressure roller 26 as shown in FIG. 7(c) (step S12). Thereafter, the paper feed step motor 17 is rotated in the reverse direction to perform a reverse line feed by one line (step S13). This reverse line feed ensures that the leading edge of the printing paper 15 passes under the suppression roller 26 toward the platen 11 (FIG. 7(d)). Then, after the reverse line feed, the paper feed step motor 17 is rotated forward to perform a normal line feed by one line (step S14).

As a result, as shown in FIG. 7(e), the leading edge of the printing paper 15 is sent to the holding position and is pushed into the gap between the pressing roller 26 and the platen 11. Thereafter, the carriage drive motor 25 is rotated in reverse and quarterly to move the carriage 20 all the way to the left end of the platen 11. As a result, the carriage 20 moves to the pin 38 of the left bevel gear 36a.
and rotates this umbrella gardening wheel 36b to the left,
As a result, the arms 28a and 28b are moved together in the direction of arrow B in FIG. 3 to close the pressure roller 26, and the printing paper 15 is placed between the pressure roller 26 and the platen 11 as shown in FIG. 7(f). The tip is pinched (step S15). From then on,
Normal printing/correction operations are performed (step S16).

According to the above-mentioned example, in the step before the leading edge of the printing paper 15 reaches the presser position, the carriage 20 is retracted and the paper guide 22 is pressed from below to the side of the roller 26 before the normal line feed accompanying the printing operation. Since the paper guide 22 is moved to the left end position of the platen 11 so as to be removed from the center of the printing paper 15 and then a normal line feed is performed (step S9, SIO), the paper guide 22 is removed from the center of the printing paper 15, and the printing paper 15 is moved to the paper guide 22
This prevents it from being pressed against the platen 11 side. As a result, the printing paper 15 is fed straight up in the tangential direction of the platen 11 as shown in FIG. The printing paper 15 no longer hits the lower part properly and rides smoothly on the pressure roller 26, and the leading edge of the printing paper 15 can be reliably prevented from being wrinkled.

Moreover, when the leading edge of the printing paper 15 is line-feeded in a normal direction to a position corresponding to the presser foot position, the pressure roller is left open, and the printing paper is line-feeded backwards, and then the line is fed back to the position of the presser foot. Therefore (steps 312 to S14),
When the suppression roller is released (step S12), even if the leading edge of the printing paper 15 simply bends without passing below the pressure roller 26 toward the platen 11, it will then reverse line feed. By making a normal line feed, the leading edge of the printing paper 15 is reliably caught between the platen 11 and the pressure roller 26, thereby reliably preventing miscatch, and the leading edge of the printing paper 15 is caught between the platen 11 and the pressure roller 26. 11 and the pressure roller 26.

In the above 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 where it is removed from below the pressure roller 26 to the side. If the paper guide 22 is in a position where the paper guide 22 is disengaged laterally from below the pressure opening 26, the carriage 20 is not necessarily moved to the platen 11.
Even in this case, the intended purpose of the present invention can be fully achieved.

Further, in the embodiment described above, the operation of the opening/closing mechanism 39 for opening and closing the pressure roller 26 was configured to be linked to the movement of the carriage 20. The pressing roller 26 may be opened and closed by energizing and de-energizing the solenoid.

Further, in the above embodiment, in steps S13 and 814, the forward and reverse line feeds are performed one line each, but the forward and reverse line feeds may be performed two or more lines at a time. Just make the amount of reverse line feeds the same.

Furthermore, in the embodiment described above, a paper detecting means 42 for detecting the leading edge of the printing paper 15 is provided, and after this 311 paper detecting means 42 detects the leading edge of the printing paper 15, the subsequent driving step of the paper feeding step motor 17 is performed. Based on the count value, it is determined whether the leading edge of the printing paper 15 has reached the printing position/pressing position or not. The determination may be made based on the count value of the number of steps.

In addition, in the present invention, a paper detection sensor for detecting whether the leading edge of the printing paper 15 has reached the printing position/pressing position may be separately provided.

[Effects of the Invention] As is clear from the above description, in the present invention, before the leading edge of the printing paper reaches the holding position, the carriage is moved from below the pressure roller before the normal line feed in the printing operation. When the leading edge of the printing paper is moved to a position where it comes off to the side and a normal line feed is made to a position corresponding to the presser position, the press roller is opened and the printing paper is made a reverse line feed. , the printing paper is pressed against the platen by closing the suppression roller after making a normal line feed to the presser position, so that it is possible to prevent the leading edge of the printing paper from being wrinkled and to prevent miscatch. This can be reliably prevented, and the leading edge of the printing paper can be reliably caught between the platen and the pressure roller.

[Brief explanation of the drawing]

1 to 7 show an embodiment of the present invention,
Fig. 1 is a flowchart showing the flow of control, Fig. 2 is a perspective view of the main part, Fig. 3 is a sectional view taken along the line ■-■ in Fig. 2, and Fig. 4 is a - 5 is a plan view of the peripheral portion of the platen; FIG. 6 is a block diagram showing a schematic electrical configuration; FIGS. 7(a) to (f)
FIG. 2 is a vertical left side view of a portion around the platen for explaining the order of operations. FIGS. 8 to 10 are vertical left side views shown in different states to explain the prior art. In the drawing, 11 is a platen, 15 is printing paper, 20 is a carriage, 21 is a print head, 22 is a paper guide, 24 is a printing ribbon, 26 is a pressure roller, 28a and 28b are arms, 34 is a tension spring, and 36 is an umbrella. 39 is an opening/closing mechanism, 40 is a control device, and 42 is a paper detection means.

Claims (1)

[Claims] 1. A carriage provided with a print head is provided with a paper guide located opposite to the platen, and is equipped with a pressure roller that presses the print paper sent out along the platen against the platen at a holding position above the printing position. The printing device includes an opening/closing mechanism that opens and closes the pressure roller, and a control device that controls the operation of the opening/closing mechanism and the printing operation, and the control device controls printing before the leading edge of the printing paper reaches the presser position. Before the normal line feed associated with the operation, when the carriage is moved to a position where the paper guide comes off from below the pressure roller to the side, and the leading edge of the printing paper is made a normal line feed to a position corresponding to the presser position. , with the pressure roller in the open state, after performing a reverse line feed on the printing paper, and then performing a normal line feed to the presser position,
A printing device characterized in that the press roller is closed to press the printing paper against the platen.