JPH0514651A - Printer - Google Patents

Abstract

PURPOSE:To ensure a maximum print picture area matching with paper. CONSTITUTION:In the case of feeding paper sheets 8 in advance to a paper tip and tail end sensor PH4 till the sheets 8 run short, A CPU counts number of pulses outputted to a platen motor to obtain the paper length (m) of the paper 8. The paper length (m) is line number in response to number of pulses. Furthermore, in this case a line number (k) from a print start position sensor PH1 till a paper feed quantity sensor PH6 is obtained. A print length M enabling print is obtained based on the paper length (m) by taking a ratio of the line number (k) at paper feeding for a prescribed period and a line number (n) at printing into account. Paper feed quantity per one pulse differs depending whether a thermal head 16 is in contact with a platen roller 11, and when the thermal head 16 is not in contact with the platen roller 11, the paper feed quantity is not made constant. Since the print picture length M of the paper is accurately grasped loaded to a cassette under the condition as above, the maximum print picture region matching with the paper is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer.

[0002]

2. Description of the Related Art The structure of a conventional example will be described with reference to FIGS. FIG. 5 is a block diagram showing a conventional printer, and FIG. 6 is a side view of a mechanical mechanism of the conventional printer.

In FIG. 5, 1 is a mechanical mechanism including a thermal head, a platen roller, a platen motor, various sensors and the like, 2 is various sensors in the mechanical mechanism 1, an I / O interface connected to the platen motor and the like, and 3 is CP
U and 4 are ROMs in which programs and the like are stored, and 5 is RAM in which data and the like are stored.

In FIG. 6, 6 is a sheet cassette, 7 is a pickup roller, 8 is a sheet, 9 is a sheet conveying guide, and 1 is a sheet conveying guide.
0 is a clamper opening / closing mechanism, 11 is a platen roller, 12 is a timing belt, 13 is a clamper, 14 and 15 are pulleys, 16 is a thermal head, 17 is an ink sheet, 1
Reference numeral 8 is a paper discharge conveyance path, and 19 and 20 are discharge rollers. Further, PH1 is a print start position sensor, PH2 is a paper presence / absence sensor in the clamper, PH3 is a clamper opening / closing position sensor, P
H4 is a paper leading edge sensor, and PH5 is a cassette paper presence sensor.

Next, the operation of the above-mentioned conventional example will be described with reference to FIG. FIG. 7 is a flowchart showing a print sequence of a conventional printer.

In steps 21 to 23, first, CP
U3 determines the paper size by a paper cassette sensor (not shown), and sets the number of lines L corresponding to the paper size. Then, the counter n is cleared and the paper is fed.

In steps 24 to 25, when the paper 8 is fed to the paper front / rear edge sensor PH4 until the paper 8 runs out,
The CPU 3 counts the number of pulses output to the platen motor to obtain the paper length m of the paper 8. The paper length m is the number of lines according to the number of pulses. Then clamper 1
Rewind 3 to the print start position.

In steps 26 to 27, printing is performed line by line and the counter n is updated by 1. Then, the printing is repeated up to the paper size L or the paper length m. here,
The reason why the end of printing is determined by both the paper size L and the paper length m is that the paper cassette 6 does not always have a paper corresponding to the size of the cassette, and the paper front / rear sensor This is because it is prepared for a failure such as PH4.

By the way, as described above, at the time of paper feeding, the thermal head 16 is separated from the platen roller 11, and the paper 8 is fed by the timing belt 12. On the other hand, at the time of printing, the thermal head 16 and the platen roller 11 are in contact with each other, and the paper 8 is not
Sent by. Therefore, when the thermal head 16 is separated from the platen roller 11 and is in contact with the platen roller 11, the feed amount of the sheet 8 is different even if the same pulse number is output to the platen motor.

Further, when the thermal head 16 is separated from the platen roller 11, the length of the paper 8 (position of the paper 8), slippage of the timing belt 12, and the like cause the paper 8 to move.
Feed amount is not constant. Therefore, the paper length m obtained when the paper 8 is fed to the paper front / rear edge sensor PH4 until the paper 8 is exhausted has a large error when compared with the actual paper length.

[0011]

In the conventional printer as described above, there is a problem that the error of the obtained paper length is large and the image is printed on the platen roller in some cases.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a printer capable of ensuring a maximum print area suitable for a sheet.

[0013]

A printer according to claim 1 of the present invention is provided with the following means. [1] When the thermal head and the platen roller are not in contact with each other during paper feeding, the paper length is calculated based on the number of pulses output to the platen motor while the paper leading edge sensor detects the leading edge and the trailing edge of the sheet. Paper length calculation means. [2] A print length calculation unit that calculates a print length that can be actually printed from the paper length calculated by the paper length calculation unit based on the previously obtained relationship between the paper length and the print length. [3] Printing means for printing on the paper up to the printing length calculated by the printing length calculating means.

A printer according to a second aspect of the present invention comprises the following means. [1] When the thermal head and the platen roller are not in contact with each other during paper feeding, the paper length is calculated based on the number of pulses output to the platen motor while the paper leading edge sensor detects the leading edge and the trailing edge of the sheet. Paper length calculation means. [2] Line number calculating means for calculating the number of lines based on the number of pulses output to the platen motor during a predetermined period during the paper feeding. [3] A print length calculation unit that counts the number of lines in the predetermined period at the time of printing and calculates the print length that can be actually printed from the paper length based on the ratio of the number of lines at the time of feeding and the number of lines at the time of printing. [4] Printing means for printing on the paper up to the printing length calculated by the printing length calculating means.

[0015]

In the printer according to the first aspect of the present invention, when the thermal head and the platen roller are not in contact with each other by the paper length calculation means, the paper front and rear edge sensors detect the front and rear edges of the paper. The sheet length is calculated based on the number of pulses output to the platen motor during the detection. Further, the print length calculation means calculates the print length that can be actually printed from the paper length calculated by the paper length calculation means based on the relationship between the paper length and the print length which is obtained in advance. Then, the printing means prints on the paper up to the printing length calculated by the printing length calculating means.

In the printer according to the second aspect of the present invention, when the thermal head and the platen roller are in non-contact paper feeding by the paper length calculating means, the paper leading and trailing edge sensors detect the leading and trailing edges of the paper. The sheet length is calculated based on the number of pulses output to the platen motor during the detection. Further, the line number calculation means calculates the line number based on the number of pulses output to the platen motor during a predetermined period during the paper feeding. Further, the print length calculation means counts the number of lines in the predetermined period at the time of printing, and calculates the print length that can be actually printed from the paper length based on the ratio of the number of lines at the time of feeding and the number of lines at the time of printing. It Then, the printing means prints on the paper up to the printing length calculated by the printing length calculating means.

[0017]

EXAMPLES Example 1. The H / W configuration of the first embodiment of the present invention is the same as that of the conventional device shown in FIGS.
The S / W structure is different from the conventional device as described below.

Next, the operation of the above-described first embodiment will be described with reference to FIG. FIG. 1 is a flowchart showing a print sequence according to the first embodiment of the present invention.

In steps 31 to 33, first, CP
U3 determines the paper size by a paper cassette sensor (not shown), and sets the number of lines L corresponding to the paper size. Then, the counter n is cleared and the paper is fed.

In step 34, when the paper 8 is fed to the paper front / rear edge sensor PH4 until the paper 8 is exhausted, the CPU
3 counts the number of pulses output to the platen motor to obtain the paper length m of the paper 8. The paper length m is the number of lines according to the number of pulses.

In steps 35 to 36, the print length M that can be actually printed is obtained from the value of the paper length m. That is, when the paper length m is within a certain range, it is determined that the paper is a regular paper, and the print length of the regular paper is set as the actual print length M. For example, if the range of the A4 size paper length m is from 2300 lines to 2500 lines and the paper length m obtained at the time of feeding is 2490 lines, the paper is considered to be the A4 size and the maximum number of printing lines is 2400. The line is set as the actual print length M. (In the conventional sequence, 2490 lines were used as the actual print length, so printing was sometimes performed on the platen roller.) Then, the clamper 13 is rewound to the print start position.

In steps 37 to 38, printing is performed line by line and the counter n is updated by one. Then, the printing is repeated up to the paper size L or the printing length M. here,
The end of printing is judged based on both the paper size L and the print length M because the paper cassette 6 does not necessarily have a paper corresponding to the size of the cassette, and the paper front / rear sensor This is because it is prepared for a failure such as PH4.

By the way, the paper length calculating means of the present invention according to claim 1 corresponds to step 34 in the above-mentioned first embodiment of the present invention, and the printing length calculating means of the present invention goes to step 35 in the first embodiment. Correspondingly, the printing means of the present invention,
This corresponds to steps 37 to 38 in the first embodiment.

The first embodiment of the present invention, as described above,
Without adding a sensor or the like, it is possible to accurately grasp the print length of the paper loaded in the cassette with the same mechanical structure as the conventional one, and to secure the maximum print area suitable for the paper. Produce an effect.

Example 2. The H / W configuration of the second embodiment of the present invention will be described with reference to FIGS. 2 is a block diagram showing a second embodiment of the present invention, and FIG. 3 is a side view of a mechanical mechanism according to the second embodiment of the present invention.

In FIG. 2, reference numeral 1A designates a mechanical mechanism including a thermal head, a platen roller, a platen motor, various sensors, and the like, and is otherwise the same as that of the first embodiment. Further, in FIG. 3, PH6 is a paper feed amount detection sensor, and other elements are exactly the same as in the first embodiment.

Next, the operation of the above-described second embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a print sequence according to the second embodiment of the present invention.

In steps 41 to 43, first, CP
U3 determines the paper size by a paper cassette sensor (not shown), and sets the number of lines L corresponding to the paper size. Then, the counter n is cleared and the paper is fed. Also, the print length M is set to the maximum hexadecimal value "FFFFH".

In steps 44 to 45, when the paper 8 is fed to the paper front / rear edge sensor PH4 until the paper 8 is exhausted,
The CPU 3 counts the number of pulses output to the platen motor to obtain the paper length m of the paper 8. The paper length m is the number of lines according to the number of pulses. At this time, the number k of lines from the print start position sensor PH1 to the paper feed amount detection sensor PH6 is also obtained. The number of lines k can be obtained based on the number of pulses in the period in which the sheet 8 is sent between the two sensors. The thermal head 16 is separated from the platen roller 11 during paper feeding, and the paper 8 is fed by the driving force of the timing belt 12.
Then, the clamper 13 is rewound to the printing start position.

In steps 46 to 50, printing is performed line by line and the counter n is updated by one. Printing is performed until the clamper 13 is detected by the paper feed amount detection sensor PH6. The value of the counter n at this time indicates the number of lines from the printing start position sensor PH1 to the paper feed amount detection sensor PH6. During the printing, the thermal head 16 and the platen roller 11 are in contact with each other, and the paper 8 is fed by the driving force of the platen roller 11. Then, at this time, the printable length M is obtained from the paper length m in consideration of the ratio of the number of lines k at the time of feeding and the number of lines n at the time of printing in the predetermined period. That is, M = m ×
Calculated by (n / k). After that, printing is repeated up to the paper size L or the printing length M. Here, the reason why the end of printing is judged by both the paper size L and the printing length M is that the paper cassette 6 does not always have a paper corresponding to the size of the cassette, and the paper This is because the front / rear edge sensor PH4 and the like are prepared for a failure.

By the way, the paper length calculating means of the present invention according to claim 2 corresponds to the first half of step 44 in the above-mentioned second embodiment of the present invention, and the line number calculating means of the present invention in step 44 in the second embodiment. The print length calculating means of the present invention corresponds to the latter half of the above, and in the second embodiment, the print length calculating means performs steps 48 and 4.
9, and the printing means of the present invention corresponds to steps 46, 47 and 50 in the second embodiment.

In the twin timing belt system, the paper feed amount of one pulse differs depending on whether the thermal head 16 is in contact with the platen roller 11. Also,
When the thermal head 16 is not in contact with the platen roller 11, the sheet feed amount is not constant. Even under such a condition, since the second embodiment of the present invention is newly provided with the paper feed amount detection sensor PH6 as described above, it is possible to accurately grasp the printing length M of the paper loaded in the cassette. As a result, it is possible to secure the maximum print area suitable for the paper.

Example 3. Although the paper feed amount detection sensor PH6 is added in the second embodiment, the sensor P
Without adding H6, a mark is added for a predetermined period of the paper 8 and the number of pulses between the marks is obtained at the time of paper feeding and at the time of printing, and the same operation can be expected by considering the ratio.

[0034]

The printer according to claim 1 of the present invention is
As described above, when the thermal head and the platen roller are in non-contact feeding, the paper length is based on the number of pulses output to the platen motor while the paper front and rear edge sensors detect the front and rear edges of the paper. And a print length calculation means for calculating a print length that can be actually printed from the paper length calculated by the paper length calculation means based on the relationship between the paper length and the print length that has been obtained in advance. Further, since the printing means for printing the print length up to the print length calculated by the print length calculating means is provided, the maximum print area suitable for the paper can be secured.

As described above, in the printer according to the second aspect of the present invention, when the thermal head and the platen roller are not in contact with each other at the time of sheet feeding, the sheet leading edge sensor detects the leading edge and the trailing edge of the sheet. Sheet length calculating means for calculating the sheet length based on the number of pulses output to the platen motor, and the number of lines for calculating the number of lines based on the number of pulses output to the platen motor in a predetermined period during the paper feeding Calculation means and print length calculation means for counting the number of lines in the predetermined period at the time of printing and calculating the print length that can be actually printed from the paper length based on the ratio of the number of lines at the time of feeding and the number of lines at the time of printing. And a printing means for printing on the paper up to the printing length calculated by the printing length calculation means, the effect that the maximum printing area suitable for the paper can be secured To.

[Brief description of drawings]

FIG. 1 is a flowchart showing the operation of Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a side surface of a mechanical mechanism according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional printer.

FIG. 6 is a diagram showing a side surface of a mechanical mechanism of a conventional printer.

FIG. 7 is a flowchart showing the operation of a conventional printer.

[Explanation of symbols]

3 CPU 8 sheets 11 Platen roller 12 Timing belt 13 Clamper 16 thermal head 17 ink sheet PH1 Print start position sensor PH4 Paper leading edge sensor PH6 Paper feed amount detection sensor

Claims (2)

[Claims] 1. A sheet length based on the number of pulses output to a platen motor while a sheet front and rear edge sensor detects the leading edge and the trailing edge of the sheet when the thermal head and the platen roller are in non-contact feeding. Paper length calculation means for calculating
A print length calculation means for calculating a print length that can be actually printed from the paper length calculated by the paper length calculation means based on the relationship between the paper length and the print length obtained in advance, and calculated by this print length calculation means A printer comprising: a printing unit that prints on the sheet up to the specified printing length. 2. The paper length based on the number of pulses output to the platen motor while the paper front and rear edge sensors detect the front and rear edges of the paper when the thermal head and the platen roller are in non-contact paper feeding. Paper length calculation means for calculating
In the case of the paper feeding, a line number calculating means for calculating the number of lines based on the number of pulses output to the platen motor in a predetermined period, the number of lines in the predetermined period at the time of printing, and the line number at the time of feeding and the time of printing A print length calculation means for calculating a print length that can be actually printed from the paper length based on the ratio to the number of lines; and a print means for printing on the paper up to the print length calculated by the print length calculation means. A printer characterized by.