JP2002292946A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer capable of suppressing generation of a sound, a vibration and a heat by a method wherein an output power of a motor for conveying a paper is varied based on a size of a paper and the motor is driven by an optimum driving force. SOLUTION: In a label printer, a distance between partition plates 7 of a paper holder 6 is detected by a size sensor, and then the output of the motor 16 for conveying a paper is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer for printing using a thermal head while transporting printing paper.

[0002]

2. Description of the Related Art Thermal printers have low operating noise and are widely used for business such as receipt and label issuance.

For example, in a type of label printer, a printing section including a thermal head and a platen roller and a sheet supply section for storing printing paper are provided in a housing, and the platen roller is driven by a transport motor (neither is shown). The printhead is driven to record desired print information on a continuous label body (print paper) conveyed between the printhead and the platen roller by the thermal head.

Here, in many cases, printing sheets of a plurality of different sizes can be set in the sheet supply section.

[0005]

The above prior art has the following problems. That is, as shown in FIG.
When printing on the narrow printing paper W, the contact area between the thermal head 3 and the platen roller 4 becomes large. At this time, the coefficient of friction between the platen roller 4 (rubber) and the thermal head 3 is large. Large torque is required.

On the other hand, as shown in FIG.
When printing is performed on the thermal head 3 and the platen roller 4
Although the contact area is small and the coefficient of friction between the platen roller 4 and the thermal head 3 is small, the weight of a large paper roll is large.

For this reason, in the conventional printer, the output of the paper transport motor is fixed at a large value so that the driving force of the paper has a margin even when the paper of any size is set and printed.

Here, a stepping motor (pulse motor) is used as a sheet transport motor so that the sheet can be positioned in the printing section. Since this stepping motor performs intermittent drive in which drive-stop is repeated in small steps. Increasing the speed and torque tends to increase vibration and noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and makes it possible to vary the output of the paper transport motor based on the paper size and to drive the paper transport motor with an optimal driving force to reduce noise, vibration and noise. An object of the present invention is to provide a thermal printer that suppresses generation of heat and the like.

[0010]

In order to solve the above-mentioned problems,
The feature of the configuration adopted by the present invention resides in that a paper size detecting means and a motor control means for controlling an output of a motor based on a detection result of the detecting means are provided.

With the above configuration, it is possible to control the output of the motor according to the paper size, thereby improving the quietness of the printer.
Power saving can be achieved.

[0012]

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

First, FIGS. 1 and 2 are external views of a mechanism showing a preferred configuration example of a label printer according to the present invention, FIGS. 3 and 5 are diagrams showing a configuration of a sheet size detecting means, and FIG. 4 is a label. FIG. 2 is a block diagram illustrating an electrical configuration of the printer.
As shown in FIGS. 1 and 2, the label printer 1 has a thermal head 3 and a platen roller 4 at one end inside a housing 2.
And a paper holder 6 serving as a sheet supply unit for accommodating a roll R around which the printing paper W is wound, and a platen roller 4 is driven by a transport motor 16 to be described later. Desired print information is recorded on the print paper W conveyed between the platen rollers 4 by the thermal head 3.

S is a paper position sensor provided between the paper holder 6 and the printing unit 5, and the paper position sensor S includes:
For example, a transmission type or reflection type optical sensor in which a light emitting unit and a light receiving unit are arranged separately is used. The paper position sensor S detects an eye mark E made of black ink or the like printed on the printing paper W at a predetermined interval, and detects one page (one sheet) of the printing paper W.
Used to detect minutes.

As shown in FIG. 2, the paper holder 6 includes a pair of partition plates 7, 7 having locking projections 11 projecting inward, and each of the partition plates 7 is provided at the center of the printing unit 5. The center distributing mechanism 8 is movably supported in conformity with the racks. The center distributing mechanism 8 is provided between two opposing racks 9, 9 and between the respective racks 9. And a pinion 10.

In the above-described paper holder 6, when each of the locking projections 11 is hooked on the hole in the center of the roll R, and the width is shifted by one partition plate 7, the rack 9 attached to the partition plate 7 rotates the pinion 10. The other partition plates 7 are moved in parallel via the other rack 9, and the roll R is sandwiched between the respective partition plates 7 to position the printing paper W at the center between the thermal head 3 and the platen roller 4. Thus, the paper holder 6 rotatably supports the printing paper W of a plurality of different sizes (widths) and supplies the printing paper W toward the center of the printing unit 5. Further, the paper holder 6
Is provided with a paper size (width) sensor 20 as shown in FIG. The paper size sensor 20 is composed of, for example, a rotary variable resistor 23 having a shaft connected to the pinion 10 of the center sorting mechanism 8. The rotation angle of the pinion 10 changes with a change in the paper width, and the rotation angle varies according to the angle. Output the resistance value. Next, in FIG. 4, reference numeral 12 denotes a CPU (central processin) for controlling each unit.
g unit), 13 is a RAM for storing various data
(Random access memory), 14 is a ROM (read only memory) storing a predetermined control program and data for performing control, 1
5 is a motor control unit for controlling the motor 16, 17 is an interface unit for receiving commands and print data from an unshown external device such as a personal computer, 18 is a position sensor control unit for controlling the paper position sensor S, and 19 is a paper size. A size sensor control unit that controls the sensor 20 and a print control unit 21 that controls the thermal head 3. Reference numeral 22 denotes a printing speed setting unit for setting the printing speed of the printer, which can be variably set by switches, software commands, menu selection, and the like.

The label printer according to the present embodiment has the above configuration, and variably controls the output of the motor 16 based on the data detected by the paper size sensor 20 and the set printing speed.

Although the method is not necessarily limited, the coefficient of friction between the printing paper and the thermal head and the weight of the printing paper roll are specified values for each product. Is stored in the ROM 14,
Control for collating this is performed.

If the set value of the printing speed is large (small), the printing speed is increased (lowered) and controlled. The motor 1
Output control 6 can be performed using conventional means such as increasing or decreasing the current (voltage) value, increasing or decreasing the pulse width or number applied to the motor. Thus, according to the present embodiment, the output of the paper transport motor 16 is controlled to a necessary and sufficient value according to the width of the paper W, and noise, vibration,
Heat generation is suppressed. In the above embodiment, the case where the width of the printing paper (label) is detected as the paper size has been described as an example. However, instead of this, the vertical pitch of the paper, that is, the distance between the adjacent eye mark E and The size may be used, and the product (area) of the vertical pitch and the horizontal width may be used as the paper size. Further, the case where the paper size sensor 20 is provided on the pinion 10 of the center distribution mechanism 8 is illustrated, but as shown in FIG. 5, a linear variable resistor 24 is provided on at least one of the partition plates 7, and the paper holder is It can also be a one-sided type, not only a variable resistor, but also a capacitance, light,
Various detection means such as ultrasonic waves can be used.

Further, although a label printer has been exemplified as the thermal printer, it may be used for other printers such as a journal printer.

[0021]

As described in detail above, according to the present invention,
Since the motor control means for controlling the output of the motor based on the detection result of the paper size detection means and the printing speed is provided, the output of the motor according to the paper size can be controlled, thereby improving the quietness of the printer and saving power. Can be.

[Brief description of the drawings]

FIG. 1 is a side external view illustrating a configuration example of a label printer according to an embodiment.

FIG. 2 is an external view of the same as viewed from above.

FIG. 3 is a configuration diagram of a sheet size detection unit.

FIG. 4 is a block diagram illustrating an embodiment of a label printer.

FIG. 5 is a configuration diagram illustrating another sheet size detection unit.

FIG. 6 is an explanatory diagram showing a relationship among a thermal head, a platen roller, and printing paper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Label printer 3 Thermal head 4 Platen roller 15 Motor control part (motor control means) 16 Motor S Paper position sensor (detection means) 20 Paper size sensor (detection means)

Claims (1)

[Claims] 1. A thermal head that generates dots based on print data, a platen roller that rotates with a print sheet interposed between the thermal head and transports the print paper,
A thermal printer that includes a transport motor that drives the platen roller and records an image on a printing paper by moving the heating dots of the thermal head and the paper; and based on a detection result of the paper size detection unit and the detection unit. A thermal printer comprising a motor control means for controlling an output of a motor.