JP2000118078A - Apparatus for adjusting gap of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a line feed accuracy in handling a paper having perforations such as a passbook or the like by adjusting a gap amount between a platen and a printing head to be a predetermined print gap amount at the time of printing and a gap open amount at the time of feeding lines, and correcting the gap open amount in accordance with a line feed time. SOLUTION: In printing to a passbook 50 by a printer, since the passbook 50 is different in thickness between a front and a rear parts of a fold part 51 when the passbook is open, a gap amount between a printing head 31 and a platen 45 is changed by a difference of the thicknesses at a line feed time via the fold part 51. In other words, a motor 36 is rotated in accordance with a paper thickness, thereby moving a carriage 33 loading the printing head 31 close or away to the platen 45 via an eccentric shaft 35. The gap amount is thus adjusted. When a line feed amount is large such as when a page is changed or the like, a gap open amount between the printing head 31 and platen 45 is changed to increase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap adjusting device for a printer.

[0002]

2. Description of the Related Art Conventionally, as a paper feeding structure of a printer, a driving roller on a printer main body side is provided, and a driven roller is provided on a paper guide section detachably mountable to the printer main body. When attached,
There is a paper feed mechanism in which a driven roller is pressed against a driving roller by a spring.

[0003] Since a continuous form is fed according to the tractor standard, the pressing force of the driven roller is sufficient for a light force necessary for stretching the paper. If this pressing force is strong, sprocket holes are formed and the tractor comes off. In addition, in the case of thick paper such as a postcard, it is necessary to increase the pressing force of the driven roller so as not to cause a slip or the like, and since the pressing force suitable for both continuous form and single form cannot be obtained, switching is necessary. Yes.

Further, when handling a recording medium having a folded portion in an open state, such as a passbook, since the thickness of the folded portion is usually different at the front portion and the rear portion, when the folded portion is inserted, a line feed is performed. In addition, it is necessary to change the gap amount between the print head and the platen depending on the difference in thickness before and after the folded portion. Further, at the time of a line feed across a folded portion, there is a problem that a load is applied to the print head or the ink ribbon guide due to a step difference before and after the folded portion, or an appropriate line feed amount cannot be obtained due to folding at the folded portion. .

Further, in a conventional printer, the gap between the print head and the platen is increased by a certain amount in order to secure a paper traveling path and feed the paper stably during a line feed operation. Line feed operation was performed. However, when handling a sheet having perforations between pages, such as a continuous form, if the projection of the continuous form perforation is large, the print head is caught in the perforation when performing a line feed to the beginning of the next page. In some cases, line feed accuracy was reduced.

[0006]

The object of the present invention is as follows.
A print gap adjusting device for a printer that sets a gap open amount in accordance with a line feed amount during a line feed operation so that an appropriate line feed accuracy can be obtained even when handling paper having perforations such as a continuous form. The purpose is to provide.

[0007]

According to the present invention, there is provided a paper conveying means for passing a recording paper between a platen and a print head, and a predetermined print gap when printing the gap amount between the platen and the print head. A gap adjusting means for adjusting the gap open amount according to a line feed time from the start of the line feed to the end of the line feed. An apparatus is provided.

When the line feed amount is large, the gap open amount is set large. Conversely, when the line feed amount is small, the gap open amount is set small. Page), a sufficient gap open amount is obtained, and print quality is not impaired.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a side view showing a first embodiment of a paper feed mechanism of a printer according to the present invention.
FIG. 3 is a plan view of the paper guide unit of the first embodiment. On the main body (base frame) 1 side of the printer device, a driving roller 2 for driving paper, a print head 3, a platen 4, and a cam mechanism 5 described later are provided. The cam mechanism 5 includes a cam 6, a cam driving motor 7, and an intermediate gear 8.

Arms 11 for detachably attaching the guide section 10 to the main body 1 are provided on both sides of the paper guide section 10 detachably attached to the main body 1. In addition, a driven roller 12 is provided which is opposed to the driving roller 2 and in contact with the upper side while the guide portion 10 is attached to the main body 1. The driven roller 12 includes a plurality of rollers corresponding to the number of the driving rollers 2, and is fixed to the shaft 13. Both ends of the shaft 13 are supported by the guide unit 10 so as to be movable up and down and rotatable.

The guide portion 10 has a driven roller 12
Springs 14 for pressing against the drive roller 2
Is provided. These springs 14 come into contact with both ends of the roller shaft 13, and the ends thereof are connected to the roller shaft 13.
And faces the cam 6. When the roller shaft 13 is pressed downward by these springs 14, the driven roller 11 is pressed against the drive roller 2 with an appropriate pressure.

In this embodiment, as a recording sheet fed in the direction of the arrow P, either a single sheet consisting of only a single sheet or a continuous sheet in which a plurality of sheets are overlapped can be used. The pressing force of the sheet acting between the driving roller 2 and the driven roller 12 is changed depending on whether the cut sheet is a continuous form. That is, in the case of a continuous book that does not require a strong pressing force of the driven roller because the paper is sent according to the tractor standard, the motor 7 is driven to rotate the cam 6 clockwise in FIG. Of the driven roller 12 does not act on the shaft 13 of the driven roller 12, thereby reducing or eliminating the pressing force of the driven roller 12 against the drive roller 2.
At this time, almost only the own weight of the driven roller 12 acts on the driving roller 2.

On the other hand, in the case of a cut sheet requiring a pressing force,
The cam 6 is rotated counterclockwise in FIG. 1 by driving the motor 7 in the reverse direction, and the pressing force of the spring 14 is applied to the shaft 1 of the driven roller 12.
3, the pressing force of the driven roller 12 against the driving roller 2 is increased. FIG. 3 is a side view showing a second embodiment of the paper feeding mechanism of the printer according to the present invention. In the first embodiment shown in FIG.
However, in the second embodiment,
The cam 6 is configured to act on the shaft 13 of the driven roller 12.

That is, the cam 6 is in contact with the vicinity of both ends of the shaft 13 of the driven roller 12, and the same as in the first embodiment,
In the case of a continuous form, the motor 7 is driven to rotate the cam 6 clockwise in FIG. 3, and the shaft 13 of the driven roller 12 is pushed up slightly to reduce the pressing force of the driven roller 12 against the driving roller 2. In the case of a single sheet, the motor 7 is driven in the reverse direction to rotate the cam 6 counterclockwise in FIG. 3 so that the pressing force of the spring 14 acts on the shaft 13 of the driven roller 12.
The pressing force of the driven roller 12 against the driving roller 2 is increased. Other configurations and operations are the same as those of the first embodiment.

FIGS. 4 and 5A are side views showing a third embodiment of the paper feed mechanism of the printer according to the present invention. In the third embodiment, a fixed shaft 15 is provided on the guide portion 10, a plurality of covers or frame members 16 are attached to the fixed shaft 15 so as to be pivotable at intervals, and the driven roller 12 is driven by each frame member 16. Mounted rotatably. When the guide member 10 is mounted on the printer main body 1, the driven roller 12 faces the drive roller 2 on the main body 1 side.

The spring 14 contacts the upper side of the frame member 16 and
The driven roller 12 is pressed against the driving roller 2 by pressing the frame member 16 downward. The tip of the spring 14 extends beyond the frame member 16, and is located above a shaft 17 movably provided on the guide portion 10 up and down. The cam 6 is disposed below the vertical movable shaft 17 so as to be in contact therewith.

In the case of a continuous book, the motor 7 is driven to drive the cam 6
Is rotated clockwise in FIG. 4 to push up the vertical movable shaft 17 and push up the spring 14. Therefore, the pressing force of the spring 14 does not act on the frame member 16 and
Thereby, the pressing force of the driven roller 12 against the driving roller 2 is reduced or disappears. At this time, the driven roller 1
Reference numeral 2 denotes that only the own weight including the frame member 16 acts on the drive roller 2.

In the case of a single sheet, the motor 7 is driven in the reverse direction to rotate the cam 6 counterclockwise in FIG.
7 is allowed to go down. Thereby, the spring 14
Pushes the frame member 16 downward, and the pressing force of the driven roller 12 against the drive roller 2 increases. FIG. 5B shows the third
A part of a fourth embodiment obtained by modifying the embodiment is shown. In the fourth embodiment, two springs 14a, 1
4b is provided. One spring 14a is short and ends at the frame member 15, while the other spring 14b has its tip extending beyond the frame member 16 as in the case of the third embodiment. It is located in. Under the upper and lower movable shafts 17, cams 6 are provided in the same manner as in the third embodiment.
Are arranged to be in contact with each other.

In the fourth embodiment, the pressing force of the spring 14a always acts on the driven roller 12 via the frame member 16, and the driven roller 12 is in contact with the driving roller 2 at a predetermined pressure. That is, in the case of a continuous book, the spring 14 b is pushed upward by pushing the vertical movable shaft 17 upward by the cam 6, so that the spring 14 b does not act on the frame member 16. At this time, only the pressing force of the other spring 14a acts on the driven roller 12, and eventually the driven roller 1
2, the pressing force on the drive roller 2 is weak. In the case of a single sheet, the vertical movable shaft 17 is lowered by the cam 6, and the frame member 16 is pressed down by both springs 14a and 14b, so that the pressing force of the driven roller 12 against the driving roller 2 is increased.

FIG. 6 shows a fifth embodiment of the paper feeder of the printer according to the present invention. In the case of processing a passbook as shown in FIG. This is to correct the line feed amount when passing through a set. FIG.
, 31 is a print head, 32 is a paper detection sensor,
33 is a carriage on which the print head 31 and the paper detection sensor 32 are mounted, 34 is a guide shaft on which the carriage 33 moves, 35 is an eccentric shaft, and 36 is a pulse motor. Reference numeral 41 denotes a paper insertion unit top plate, reference numerals 42 and 43 denote paper feed rollers, reference numeral 44 denotes a paper feed (LF) motor, reference numeral 45 denotes a platen, and reference numeral 46 denotes a stacker.

As shown in FIG. 7, the passbook 50, which is a recording medium, has a front portion 52 (thickness t ₂ ) of the folded portion 51 in an opened state.
And the rear portion 53 (thickness t ₁ ) usually have different thicknesses. After the passbook 50 has been printed on the front portion 52, the passbook 50 is displayed on the rear portion 53.
However, when a line feed is performed by inserting the folded portion 51, the gap between the print head 31 and the platen 45 needs to be changed because there is a difference in thickness between the front portion 52 and the rear portion 53. is there. When a line feed is performed with the folding section 51 interposed, the print head 31 or the ink ribbon guide (not shown) may generate a load due to a step between the front section 52 and the rear section 53, or may be folded at the folding section. The proper line feed amount may not be obtained due to looseness.

In this embodiment, a mechanism is provided in which the gap is automatically adjusted via the eccentric shaft 35 by rotating the motor 36 according to the thickness of the sheet. Such an automatic gap amount adjusting mechanism itself is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-16623.
No. 8, etc., it is already known and need not be described in detail here. Therefore, in this embodiment, correction of a line feed amount due to a step before and after the folding portion 51 of the passbook 50 will be described.

First, when the passbook 50 is inserted in the direction of the arrow P along the upper surface of the paper insertion unit top plate 41 of the printer, the paper feed motor 44 is rotated in the forward direction to rotate the paper feed rollers 42,
At 43, the passbook 50 is sent in the forward direction (arrow P). A paper detection sensor 32 provided in the vicinity of the print head 31 detects the front end of the passbook, and then detects the rear end of the passbook.
F) Stop the motor 44. Here, the length L of the passbook 50
Recognize.

Next, the paper feed (LF) motor 44 is rotated in the reverse direction, and the passbook 50 is moved backward by α (α <L / 2). Here, the LF motor 44 is stopped, and the paper thickness (thickness t ₁ ) at the rear portion 53 of the passbook 50 is detected. Next, L
The F motor 44 is further rotated in the reverse direction, and the passbook 50 is further retracted by L / 2. Here, the LF motor 44 is stopped, and the paper thickness (thickness t ₂ ) at the front portion 52 of the passbook is detected.

Next, the LF motor 44 is further rotated in the reverse direction until the paper detection sensor 32 detects the front end of the passbook 50, and the LF motor 44 is temporarily stopped. Next, the LF motor 44 is rotated in the forward direction until the printing start line of the front part 52 of the passbook 50 is reached, and the printing operation is started. When the printing and the line feed operation are repeated and the processing of the front part 52 of the passbook 50 is completed, a line feed is executed by adding a line feed correction amount obtained as follows in a line feed across the folding part 51.

[0026] Here, x is the front and rear of the step is line feed correction amount when the t _0. The value of x is obtained by experiments depending on the type and thickness of the passbook.

After the line feed, the rear part 53 of the passbook 50 is processed.
The printing operation ends. FIG. 8A shows a flow chart of a paper feeding device for a printer according to a sixth embodiment of the present invention. FIG. 8B is a flowchart of a conventional example corresponding to the embodiment. When processing a continuous form or a cut sheet using a printer having a structure as shown in FIG. 6, as described above, conventionally, as shown in FIG. In order to feed the paper stably during operation, the line feed operation was performed by widening the gap between the print head and the platen by a certain amount. If it is large, the print head may be caught in a perforation when performing a line feed to the beginning of the next page, and the line feed accuracy may be reduced.

Therefore, in this embodiment, when a line feed amount is large, such as when a page break is performed, the gap open amount between the print head and the platen is increased, and this gap is used during a normal line feed. By changing the gap open amount according to the line feed amount, such as reducing the amount, the paper running path is secured and the line feed accuracy is improved even when the convex portion of the continuous perforation is large.

That is, as shown in FIG. 8A, line feed data is received from the host computer. When the line feed operation is executed, the line feed execution time is calculated from the line feed amount and the LF motor is started. From the line feed execution time calculated during the line feed operation, how much the gap between the print head and the platen can be opened is determined, and the cam drive pulse motor 36 in FIG. 6 is started. As a result, the carriage 33 rotates counterclockwise about the guide shaft 34 to open the gap between the platen 45 and the print head 31.

When the gap open operation is completed, the pulse motor 36 is started in the reverse direction to start the gap close operation by the same amount as the gap open amount. This operation is also performed during the line feed operation. At the end of the line feed operation, the gap open / close operation also ends, and the gap between the print head and the platen is
It is the same as before starting the line feed operation.

By performing the above-described gap open processing operation, it is possible to secure a paper traveling path and improve the line feed accuracy even for a paper having a large convex portion such as a perforation of a continuous copy paper. Furthermore, since the gap open / close operation is performed during the line feed operation, the line feed accuracy can be improved without lowering the performance. As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various forms, modifications, and corrections are made within the spirit and scope of the present invention. It should be noted that the like is possible.

[0032]

As described above, according to the present invention, at the time of a line feed operation, the gap open amount can be set according to the line feed amount. Even when breaking a line beyond that,
Appropriate line feed accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a paper feeding structure of a printer according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a paper guide unit of the first embodiment.

FIG. 3 is a schematic side view of a paper feeding structure of a printer according to a second embodiment of the present invention.

FIG. 4 is a schematic side view of a paper feeding structure of a printer according to a third embodiment of the present invention.

FIG. 5A is a partial plan view of the third embodiment, and FIG. 5B is a partial plan view of a fourth embodiment obtained by modifying the third embodiment.

FIG. 6 is a schematic side view of a printer having a paper feeding structure according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view of a passbook used in a fifth embodiment.

FIG. 8 is a flowchart according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Printer main body 2 ... Drive roller 3 ... Print head 4 ... Platen 5 ... Cam mechanism 6 ... Cam 7 ... Intermediate gear 10 ... Paper guide part 11 ... Arm 12 ... Follower roller 13 ... Roller shaft 14 ... Spring 15 ... Fixed shaft 16 ... Frame member 17 ... Vertical movable shaft 31 ... Print head 32 ... Paper detection sensor 33 ... Carriage 34 ... Gite shaft 35 ... Eccentric shaft 36 ... Pulse motor 41 ... Paper insertion top plate 42, 43 ... Paper feed roller 44 ... Paper feed (LF) Motor 45 ... Platen 46 ... Stacker 50 ... Passbook

Claims (1)

[Claims] 1. A paper conveying means for passing recording paper between a platen and a print head, and a gap amount between the platen and the print head is set to a predetermined print gap amount when printing, and a gap open amount is set for line feed. A gap adjusting device for a printer, comprising: a gap adjusting unit that adjusts the gap open amount according to a line feed time from a line feed start to a line feed end.