JPH04251761A - Thermal type line printer - Google Patents

Abstract

PURPOSE:To obtain enabling signal lines in numbers smaller than numbers with which a thermal head is divided up into groups. CONSTITUTION:In a thermal type line printer equipped with a thermal head in which one line of heating units are formed of (m) heating units, each of which corresponds to one dot, and the (m) heating units are divided into (n) groups (lower groups), each of which contains (x) heating units, and printing is made by specifying each of the lower groups for enabling one after another, the aforementioned (n) lower groups are divided into beta upper groups, each of which contains alpha lower groups. Then enabling signals for specifying the enablings for each of the beta upper groups, and the enabling signals for specifying the enablings for each of the alpha lower groups are generated, and one of the lower groups is specified for the enabling by the result obtained by logical operation mode to the aforementioned upper enabling signals and the lower enabling signals.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal line printer, and more particularly to a thermal line printer incorporated into a micro-compact information processing device such as a handy terminal.

[0002] Generally, when using computers to save labor, in fields where the location of data generation or use cannot be specified, it is necessary to visit each computer location, which is inefficient and inconvenient. It is.

[0003] Therefore, in order to meet the demand for direct input and output of data in the field, so-called handy terminals, which are terminals dedicated to input and output that are miniaturized to the extent that they can be held in one hand, are used. Such handy terminals are basically equipped with a keyboard for inputting data and a display for displaying data. However, depending on the site, printed matter such as receipts may be required, and an ultra-compact printer that can be built into a handy terminal is required.

0004

[Prior Art] A printer with a built-in handy terminal is required to be small, have a simple mechanism, and have low power consumption, and generally a thermal type (thermal transfer type or heat sensitive type) line printer is used. It will be done.

[0005] The head of a thermal line printer is
Printing resolution can be improved by arranging a large number of heating elements in a line to increase the density of the heating elements. For example, the line width is 4
In the case of an inch (approximately 10 centimeters) head with 640 heating elements (640 dots), the element density would be approximately 6 dots per millimeter.

By the way, driving as many as 640 heating elements at once poses a problem in terms of power consumption, especially in the case of battery-powered handy terminals. Therefore, as shown in FIG. 4, m heating elements D1 to Dm are divided into x groups (x = 5 in the figure) into n groups G1 to Gn, and each group is sequentially driven. What is done is done. The driving power can be reduced to 1/n by simple calculation.

FIG. 5 is a head circuit diagram of a thermal line printer. In this figure, for the sake of simplicity, the number of heating elements is 10, and two groups of 5 elements, Ga and Gb
It is divided into That is, m=10, x=5, and n=2.

In FIG. 5, heating elements 1 to 10 are connected between power supplies VCC and VDD via dedicated switching transistors T1 to T10, respectively, and an AND gate AN is connected to the base of each transistor T1 to T10.
The outputs of D1 to AND10 are connected.

AND1 to A belonging to the first group Ga
Print dot data dH1 to dH5 (H is the data block number corresponding to Ga and Gb) from the shift register R is given to each one end input of ND5, and the first enable signal SENBL1 is given to each other end input. It is being In addition, the remaining AND6 to AN belonging to the second group Gb
Print dot data dH1 to dH5 from the shift register R is similarly applied to one end input of D10, and a second enable signal SENBL2 is applied to each other end input.

In such a configuration, the print data dH
If data for 5 dots corresponding to group Ga is given as 1-5 and the enable signal SENBL1 on the group Ga side is set to high level, each dot data dH1 to dH5 taken out from shift register R
According to the logic, transistors T1~ on the group Ga side
T5 is turned on/off, and heating elements 1 to 5 of group Ga are driven.

That is, according to the example shown in FIG. 5, the heating elements can be driven in groups by simply activating the two enable signals SENBL1 and SENBL2 alternately, and the power consumption can be reduced to 1/the number of groups. can be reduced.

0012

[Problems to be Solved by the Invention] However, such conventional thermal type line printers have a configuration that includes the same number of enable signal lines as the number of groups, so for example, it is difficult to further reduce power consumption. If an attempt was made to increase the number of groups using a printer, there was a problem in that the number of signal lines between the printer body and the head would increase.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to obtain fewer enable signal lines than the number of head group divisions.

[0014]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a thermal head in which one line is composed of m heating elements, each of which corresponds to one dot, as shown in FIG. 1. In a thermal line printer, the m heating elements are divided into x groups to form n groups (lower groups), and each lower group is sequentially enabled and printed. divides the lower groups into β upper groups each containing α groups, an upper enable signal specifying each of the β upper groups, and a lower enable signal specifying each of the α lower groups. The present invention is characterized in that one of the lower groups is specified to be enabled based on the result of a logical operation between the upper enable signal and the lower enable signal.

[0015]

[Operation] In the present invention, one lower group is specified by the logical operation result of an upper enable signal that specifies each of β upper groups and a lower enable signal that specifies each of α lower groups. .

[0016] Here, the total number of groups is n, and n is α
It is expressed as ×β. Therefore, the number of enable signal lines is α+
Since it is expressed as β, the number of signal lines is (α × β) − (α + β)
can only be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. 2 and 3 are diagrams showing an embodiment of a thermal type line printer according to the present invention.

In FIG. 2, G1 to G16 are n (n=16) subgroups each including x heating elements (not shown). These subgroups G1-G1
6 is divided into α (α=4) groups to form β (β=4) upper groups E1 to E4. The outputs of the AND circuits &1 to &16 are connected to the lower groups G1 to G16, respectively, and the 16 AND circuits &1 to &16
are divided into four groups like the lower groups.

AND circuit &1~ belonging to group E1
An upper enable signal i1 for specifying group E1 is given to each one end input of &4, and an upper enable signal i1 for specifying group E1 is given to each other end input.
Lower enable signals j1-j4 are provided for designating one lower group within the group.

AND circuit &5~ belonging to group E2
An upper enable signal i2 for specifying group E2 is given to each one end input of &8, and an upper enable signal i2 for specifying group E2 is given to each other end input.
Lower enable signals j1-j4 are provided for designating one lower group within the group.

AND circuit &9~ belonging to group E3
An upper enable signal i3 for specifying group E3 is given to each one end input of &12, and lower enable signals j1 to j4 for specifying one lower group within the group are given to each other end input. It will be done.

AND circuit &13 belonging to group E4
An upper enable signal i4 for specifying group E4 is given to each one end input of ~&16, and a lower enable signal j1 to j4 for specifying one lower group within the group is given to each other end input. Given.

These upper enable signals i1 to i4 and lower enable signals j1 to j4 are connected to signal lines L1 to L.
The number of signal lines L1 to L8 is 8, which is the same as the number of enable signals.
It's a book.

FIG. 3 is a schematic representation of the circuit shown in FIG. The circles marked at the intersections of the transmission paths of the upper enable signals i1 to i4 and the transmission paths of the lower enable signals j1 to j4 each represent AND circuits &1 to &16.

For example, when the upper and lower enable signals (i1, j1) connected to the AND circuit &1 are active, the enable signal SG1 specifying one lower group G1 is output from the output of the AND circuit &1. .

Therefore, if the upper enable signals i1 to i4 are sequentially applied, and the lower enable signals j1 to j4 are sequentially applied during the application of the respective upper enable signals, i1j1→i1j2→i1j3→i1j4→i2j1→
i2j2→i2j3→i2j4→i3j1→i3j2→
i3j3→i3j4→i4j1→i4j2→i4j3→
i4j4→..., the lower groups G1 to G
16 can be enabled sequentially.

As described above, according to the present embodiment, groups can be sequentially specified using a smaller number of enable signal lines (8 lines) than the number of groups (16 lines in this embodiment). this is,
n (n=16) groups (lower groups) are divided into α (
α = 4) divided into β (β = 4) upper groups E1
〜E4, and an enable signal i1 for the upper group
This is because the enable signals j1 to j4 for lower groups are generated and the number of required signal lines can be set to α+β.

That is, since the number n of lower-order groups is given by α×β, in the case of this embodiment, n=4×4=16
The number of signal lines required for each signal line is 4+4=8, and the number of required signal lines can be halved. As a result, it is possible to solve the problem of increasing the number of enable signal lines when increasing the number of groups with the intention of reducing power consumption, and it is possible to provide a thermal line printer particularly suitable for battery-powered handheld terminals. . Moreover, by reducing the number of signal lines, the connector between the printer main body and the head can be made smaller, the ease of assembly can be improved, and failure resistance can be improved as the number of contact terminals is reduced.

Note that in the above embodiment, since n=16, 16=42, so 4+4 could be obtained.
Naturally, depending on the number of n, it may not be an exponential form. In this case, it is sufficient to find the values of α and β that give the minimum addition result.

[0030]

According to the present invention, it is possible to obtain fewer enable signal lines than the number of groups, and it is possible to solve the problem of signal line increase when the number of groups is increased.

[0031] Therefore, it is possible to provide a thermal line printer suitable for battery-powered handy terminals, etc., which require particularly low power consumption.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a configuration diagram of an embodiment.

FIG. 3 is a schematic diagram of FIG. 2;

FIG. 4 is a diagram showing how heating elements are divided into groups.

FIG. 5 is a configuration diagram of a conventional printer head.

[Explanation of symbols]

G1~G16: Lower group E1-E4: Top group &1 to &16: AND circuit i1 to i4: Upper enable signal j1 to j4: Lower enable signal

Claims (1)

[Claims] Claim 1: A thermal head comprising one line of m heating elements each corresponding to one dot, and n groups (lower groups) formed by dividing the m heating elements into x units. However, in a thermal line printer that prints by sequentially enabling each lower group,
dividing the n lower groups into β upper groups each including α groups, and providing an upper enable signal specifying each of the β upper groups and each of the α lower groups; A thermal line printer is characterized in that it generates a lower enable signal and designates one of the lower groups as enabled based on the result of a logical operation between the upper enable signal and the lower enable signal.