JP2848019B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer having a function of detecting the thickness of printing paper set on a platen before starting printing and adjusting the position of a printing head in accordance with the thickness. .

[0002]

2. Description of the Related Art As shown in FIG. 6, a conventional printer having a print head position adjusting function has a ribbon mask 4 between a print sheet 2 set on a platen 1 and a print head 3. As shown in FIG.
Are arranged, and an ink ribbon 5 is set between the ribbon mask 4 and the print head 3. The above print head 3
Can be slid in the front-rear direction (the direction of arrow A and the opposite direction) together with a carriage (not shown) in order to detect the thickness of the printing paper 2.

When the thickness of the printing paper 2 is detected, the printing head 3 is moved toward the platen 1 so that the nose portion 3 a of the printing head 3 is attached to the ribbon mask 4 via the ink ribbon 5. Press to ribbon mask 4
Is brought into contact with the printing paper 2. At this time, since the ribbon mask 4 prevents the ink ribbon 5 from being pressed against the printing paper 2, it is possible to detect the paper thickness without worrying about ink stains on the printing paper 2.

After that, the print head 3 is retracted by a certain distance to secure a certain gap between the print head 3 and the print paper 2 to stabilize print quality.

[0005]

In recent years, increasing the printing speed has become an important technical problem. To increase the printing speed, the gap between the print head 3 and the printing paper 2 must be reduced. It is more advantageous to do so. However, in the above-described conventional configuration, a means for preventing the nose portion 3a of the print head 3 from pressing the ink ribbon 5 against the print paper 2 when detecting the paper thickness of the print paper 2 is provided between the print paper 2 and the print head 3. Since the ribbon mask 4 is disposed on the
Even if the gap between the printing paper 2 and the printing paper 2 was to be reduced, the ribbon mask 4 was in the way, and the gap could not be sufficiently reduced, which hindered an increase in printing speed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a printer capable of adjusting a gap between a print head and a printing paper to a minimum and contributing to an increase in printing speed. Is to provide.

[0007]

The printer according to the present invention has a function of detecting the thickness of the printing paper set on the platen before starting printing, and adjusting the position of the printing head in accordance with the detected thickness. A ribbon elevating means for retracting the ink ribbon above or below a printing position prior to detecting the thickness of the printing paper, and a print head approaching the platen side after retreating the ink ribbon. Or, a paper thickness detecting means for detecting the paper thickness of the printing paper by bringing a paper surface contact portion provided on a carriage into contact with the printing paper, and retreating the printing head after detecting the paper thickness to form the printing paper. Printing initial setting means for returning the ink ribbon to the printing position while moving the ink ribbon relative to the print head in the longitudinal direction thereof after a predetermined gap is provided between the printing head and the printing head. One in which you composed.

[0008]

When detecting the thickness of the printing paper, first, the ink ribbon is retracted above or below the printing position. Thereafter, the print head is brought closer to the platen side, and the paper contact portion provided on the print head or the carriage is brought into contact with the print paper to detect the thickness of the print paper. After detecting the paper thickness, the print head is retracted to form a predetermined gap between the print head and the print paper. Return to

In this case, since the ink ribbon is retracted prior to the detection of the paper thickness, a conventional ribbon mask (a member for preventing the print head from hitting the ink ribbon at the time of detecting the paper thickness) becomes unnecessary. The gap between the paper and the printing paper can be made smaller than before.

As described above, when the gap between the print head and the printing paper is reduced, the ink ribbon generally tends to catch on the print head when the ink ribbon is returned from the retracted position to the print position after the gap is adjusted. In the present invention,
Since the ink ribbon is returned to the printing position while being relatively moved with respect to the print head in the longitudinal direction, tension is applied to the ink ribbon, and the tension causes the ink ribbon to enter a gap between the print head and the printing paper. The ink ribbon is smoothly pulled in, and the ink ribbon is prevented from being caught on the print head.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG.
Is provided on the carriage 12. The carriage 12 is supported movably to the left and right along two guide shafts 14 and 15 provided in parallel with the platen 13. One guide shaft 14 is rotatable about an eccentric shaft 16, and the rotation causes the carriage 12 and the print head 11 to move in the front-rear direction (the direction of arrow A and the opposite direction).
It is possible to slide.

Further, a printing paper 17 is provided on the carriage 12.
Paper contact portion 18 that contacts printing paper 17 when paper pressure is detected
The paper contact portion 18 is positioned slightly closer to the platen 13 than the nose portion 11 a of the print head 11.

An ink ribbon 19 (see FIG. 4) is set between the print head 11 and the printing paper 17, and a ribbon guide 20 for guiding the ink ribbon 19 is provided.
2 (see FIGS. 2 and 4) is moved up and down by a ribbon elevating means 21. Hereinafter, the configuration of the ribbon elevating means 21 will be described with reference to FIG.

The ribbon lifting / lowering means 21 uses a pulse motor 22 as a drive source, and transmits the rotational force of the pulse motor 22 to a pinion 24 via gears 23a and 23b. The pinion 24 is engaged with a rack 26 provided on the ribbon shifter 25, and the rotation of the pinion 24 causes the ribbon shifter 25 to move up and down. The ribbon shifter 25 is provided with a guide portion 27 extending in parallel with the platen 13, and a support frame 28 of the ribbon guide 20 is fitted to the guide portion 27 so as to be slidable left and right. Thus, during a printing operation, the ribbon guide 20 slides left and right integrally with the print head 11.

In this embodiment, for example, four color ink ribbons are used as the ink ribbon 19, and color printing can be performed by vertically shifting the ink ribbon 19 by the ribbon lifting / lowering means 21.

On the other hand, the printing operation is controlled by a microcomputer (not shown), and this microcomputer partially functions as "paper thickness detecting means" and "print initial setting means" in the claims. Also, the control of the operation timing shown in FIG. 1 is executed. That is, when detecting the thickness of the printing paper 17, first, the pulse motor 2
2, the ribbon shifter 25 is raised, the ribbon guide 20 is raised, and the ink ribbon 19 is retracted above the printing position. The rising speed of the ink ribbon 19 at this time is the same as the ribbon shift speed at the time of a normal printing operation, and is higher than the ribbon lowering speed described later.

After the ink ribbon 19 is retracted, the guide shaft 14 is rotated about the eccentric shaft 16 to bring the print head 11 (carriage 12) closer to the platen 13 side.
The paper contact portion 18 is brought into contact with the printing paper 17. Whether or not this state has been determined is determined by the torque detected by a torque sensor (not shown) that detects the torque of the guide shaft 14. That is, when the torque detected by the torque sensor reaches the set value, it is determined that the paper contact portion 18 has contacted the printing paper 17 and the print head 11 is positioned at that position.
(Carriage 12) is stopped. The thickness of the printing paper 17 is detected from the stop position.

After the detection of the paper thickness, the print head 11 (carriage 12) is retracted to provide a predetermined gap with the print paper 17, and the print head 11 (carriage 1) is located at that position.
2) Stop. In this way, after a certain gap is secured between the print head 11 and the print paper 17 according to the thickness of the print paper 17, the ink ribbon 19 is lowered to the print position while being wound up. At this time, the winding speed of the ink ribbon 19 is the same as that in the normal printing operation, but the ribbon descending speed from the retracted position to the printing position is the ribbon shift speed in the normal printing operation (the dotted line in FIG. 1). Is much slower than shown). After the ink ribbon 19 is returned to the printing position in this way, the printing operation is started.

According to the above-described embodiment, the ink ribbon 19 is retracted upward from the printing position prior to the detection of the thickness of the printing paper 17, so that the conventional ribbon mask (the print head 11 is moved to the ink ribbon 19 when the paper thickness is detected). Is unnecessary, and the gap between the print head 11 and the printing paper 17 can be made smaller than before, contributing to an increase in printing speed. At this time, the wound amount of the ink ribbon 19 may be rewound before the printing operation.

As described above, the printing head 11 and the printing paper 17
When the gap between the ink ribbon 19 and the ink ribbon 19 is returned to the printing position after the gap adjustment, the ink ribbon 19 is easily caught by the print head 11, but in this embodiment, the ink ribbon 19 is Since the ink ribbon 19 is returned to the printing position while being taken, tension is applied to the ink ribbon 19, and the ink ribbon 19 is smoothly drawn into the gap between the print head 11 and the printing paper 17 by the tension. Head 11
It is possible to prevent wrinkles from being caught on the surface as much as possible.

If the ribbon descending speed when returning the ink ribbon 19 from the retracted position to the printing position is too fast, the ink ribbon 19 may be lowered before the tension of the ink ribbon 19 is sufficient. In this case, even if the ink ribbon 19 is lowered while being wound up, the ink ribbon 19 is
May get caught in the computer.

In this respect, in the above embodiment, the ink ribbon 1
9 is returned from the retracted position to the printing position, the ribbon lowering speed is much slower than the ribbon shifting speed during normal printing operation (indicated by a dotted line in FIG. 1).
Since the ink ribbon 19 is lowered slowly, the ink ribbon 19 can be sequentially released with a margin during the descending process of the ink ribbon 19, and the effect of preventing the ink ribbon 19 from being caught can be further ensured.

FIG. 6 is a flowchart showing the operation of another embodiment. In this embodiment, since the configuration is the same as that of the above-described embodiment, the description is omitted. In the present embodiment, as in the previous embodiment, the ribbon is retracted upward (s1), and the paper thickness is detected (s2). At this time, the print head has moved to a position distant from the home position (specifically, the position of the sheet detection sensor). Thereafter, in this embodiment, the ink ribbon is lowered in a stationary state without winding up (s3). At this time, the lower end of the ink ribbon is stopped at a position slightly lower than the upper end of the front end of the print head. Therefore, it is conceivable that the ink ribbon is slightly caught on the print head, but the amount is small and the ink ribbon does not wrinkle. Then, while moving the carriage to the home position (s
5) The ink ribbon is lowered to the position of the ink ribbon in actual printing.

In the above embodiment, the ink ribbon 19 is configured to perform color printing using a color ink ribbon. However, the present invention is similarly applied to a configuration using a single color ink ribbon. Can be implemented.

In the above embodiment, the ink ribbon 19
When the ink ribbon 19 is returned from the retracted position to the printing position,
Is wound up, but the same effect as in the above-described embodiment can be obtained by rewinding this.

In the above embodiment, the ink ribbon 19 is retracted "up" from the printing position prior to the detection of the paper thickness. However, it may be retracted "down". Further, the retreat operation of the ink ribbon 19 is performed as follows.
A configuration in which the ribbon cassette (not shown) is moved up and down may be adopted.

In addition, the present invention may be modified such that the paper contact portion 18 is provided on the print head 11 instead of the carriage 12, and the shape of the paper contact portion 18 may be appropriately changed. Is possible.

[0028]

As is apparent from the above description, the present invention retracts the ink ribbon prior to detecting the paper thickness of the printing paper, so that the conventional ribbon mask (the print head does not hit the ink ribbon when the paper thickness is detected). Is unnecessary, and the gap between the print head and the printing paper can be made smaller than before, contributing to an increase in printing speed.

In addition, when the ink ribbon is returned from the retracted position to the printing position, the ink ribbon is returned to the printing position while being relatively moved in the longitudinal direction with respect to the print head. Due to the tension, the ink ribbon is smoothly drawn into the gap between the print head and the print paper, and the ink ribbon can be prevented from being caught on the print head as much as possible.

[Brief description of the drawings]

FIG. 1 is a timing chart showing a temporal change of a print head position, a ribbon shift position, and a ribbon shift speed during a paper thickness detecting operation.

FIG. 2 is a side view of the ribbon elevating means.

FIG. 3 is a side view of a print head and a carriage.

FIG. 4 is a plan view of a portion around a print head.

FIG. 5 is a flowchart showing the operation of another embodiment.

FIG. 6 is a plan view of a portion around a print head showing a conventional example.

[Explanation of symbols]

Reference numeral 11 denotes a print head, 12 denotes a carriage, 13 denotes a platen, 14 denotes a guide shaft, 17 denotes a print sheet, 18 denotes a paper surface contact portion, 19 denotes an ink ribbon, 20 denotes a ribbon guide, 21 denotes a ribbon elevating means, and 22 denotes a pulse motor. , 25 are ribbon shifters.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 25/308 B41J 33/14 B41J 35/08 B41J 35/20

Claims (1)

(57) [Claims] 1. A printer having a function of detecting the thickness of printing paper set on a platen before starting printing and adjusting the position of a printing head in accordance with the thickness of the printing paper. Ribbon elevating means for retracting the ink ribbon above or below the printing position prior to detection, and a paper contact portion provided on the print head or carriage by moving the print head closer to the platen after the ink ribbon is retracted Paper thickness detecting means for detecting the paper thickness of the printing paper by contacting the printing paper with the printing paper, and after detecting the paper thickness, the printing head is retracted to open a predetermined gap between the printing paper and the printing head. And a printing initial setting means for returning the ink ribbon to the printing position while relatively moving the ink ribbon in the longitudinal direction with respect to the print head.