JPS6277956A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To enable a printing to be conducted in both travel directions of a printing head with a uniform printing quality to enhance a printing speed, by a method wherein two arrays of heating elements formed in the printing head are individually electrically conducted while travelling forward and returning so as to be selectively used according to the travel directions of the printing head. CONSTITUTION:In a printing head 1, first and second heating elements 5, 6 composed of a number of dots are longitudinally disposed in two array on one side surface of a head substrate 4 at both sides of its travel direction. In a forward, i.e. rightward, travel of a carriage, an electric current is passed through the first heating element 5, and in a return, i.e. leftward, travel, it is passed through the second heating element 6. Therefore, in either of forward and return travels of the carriage, an electric current is selectively passed through the heating element 5 or 6 in back of the travel direction of the printing head 1. In this manner, a repeated use of a multi-ink ribbon and an uniform printing quality are ensured, and a printing conducted in both travel directions of the printing head adequately enhances a printing speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal transfer printer that transfers ink from an ink ribbon onto printing paper using heat from a heating element of a print head.

[Technical Background of the Invention and Problems thereof] Conventionally, ink ribbons used in printers of this type have generally been made by coating a polyester base film with a heat-melting ink layer. In conventional thermal transfer printers, the ink ribbon is pressed against the print paper by a print head equipped with a heating element, and while the print head is moved, electricity is applied to the heating element to melt the ink and transfer it to the print paper, thereby printing. This configuration separates the ink ribbon from the printing paper as the head moves. However, this ink ribbon has the drawback that the ink layer completely peels off from the base film during printing, so it cannot be used repeatedly and the printing cost increases.

Therefore, in recent years, so-called multi-ink ribbons have been developed in which a porous layer impregnated with ink is formed on a base film. In this multi-ink ribbon, since the porous layer is impregnated with ink, it can be used repeatedly in several stages, and has the advantage that printing costs can be significantly reduced.

However, when using the second multi-ink ribbon,
The time required to separate the ink ribbon from the printing paper after ink transfer must be set shorter than in the case of using a conventional ink ribbon. This is because if the ink ribbon is separated from the printing paper after the ink melted during transfer has solidified, the porous layer will be separated from the base film by 71 degrees, making repeated use impossible. For this reason, in a thermal transfer printer that can use a multi-ink ribbon, it is necessary to arrange the heating elements of the print head in a row at a predetermined distance from the trailing edge toward the rear in the direction of movement of the print head.

Incidentally, even in this type of printer, in order to improve printing speed, it is desired that printing be performed both when the print head moves forward and when it moves backward. However,
For those that allow the use of multi-ink ribbons,
As mentioned above, it is necessary to form the heating element of the print head to one side, and if the printing head is used to simply energize the heating element during both forward movement and backward movement,
Since the time required for the ink ribbon to separate from the print paper after melting the ink differs when the print head moves forward and backward, there is a problem in that good print quality cannot be obtained in both directions.

However, it is impossible to form a heating element in the center of the print head in order to equalize conditions in both directions because a wiring pattern to the heating element must be formed in the print head.

[Objective of the invention] The present invention has been made in view of the above circumstances.
The objective is to provide a thermal transfer printer that can perform bidirectional printing with uniform print quality and improve printing speed while reducing printing costs by making it possible to use a so-called multi-ink ribbon.

[Summary of the Invention] The present invention provides a print head with two
In addition to providing a row of heating elements, a switching means is provided to switch each heating element on the rear side in the direction of movement of the print head to be energized when the print head moves forward and backward, thereby connecting each heating element to the print head. The feature is that it can be used depending on the direction of movement.

[Embodiments of the invention will be described with reference to the drawings. First, as shown in FIG. 3, the thermal transfer printer according to this embodiment includes a print head 1 and an ink ribbon 2 mounted on a carriage (not shown). The carriage is configured to be able to reciprocate from side to side in a pressed state. As shown in FIG. 2, the print head 1 has first and second dots that are located on both sides of one surface of the substrate 4 in the direction of movement and are arranged four dots downward. Two rows of heating elements 5 and 6 are formed. 7 is a heat radiating member fixed to the other surface of the head substrate 4;
is a flexible printed circuit board that connects each heating element 5.6 and a control circuit to be described later. Also, ink ribbon 2
As shown in FIG. 4, this is a so-called multi-ink ribbon formed by laminating a base film 9 made of, for example, polyester and a porous layer 10 impregnated with ink.

Now, the electrical configuration of the control circuit is shown in FIG. 1, where 11 is a microprocessor, 112 is a ROM, and 13 is a ROM.
14 is a RAM, 14 is a decoder, 15 is a data storage address storage section, and 16 is a data retrieval address storage section.

The print data is stored in a print buffer formed in a predetermined storage area in the RAM 13 at an address stored in the data storage address storage section 15, and read out according to the address stored in the data retrieval address storage section 16. Reference numeral 17 denotes a printing direction storage section which stores the printing direction, that is, the moving direction of the carriage, and the stored contents are reversed each time the carriage reaches the movement limit position. 18 is a multiplexer corresponding to a switching means, and 19.20 is a first terminal connected to each terminal of the human output and B output of the multiplexer 18.
and a second driver. The multiplexer 18 selectively outputs print data to either the human output or the B output according to the applied switching signal, and each of the first and second drivers 19 and 20 outputs the print data according to the applied print data. The first or second heating element 5.6 of the print head 1 is controlled to be energized or disconnected. 21 is a motor driver for energizing the carriage motor 22 for driving the carriage, which is connected to the latch 23.
carriage motor 22 in response to a drive signal received via
drive in a predetermined direction.

Next, the operation of this embodiment will be explained with reference to FIG. 5 as well. This should make the functional configuration of this embodiment more clear. First, at the start of the operation, as shown in steps a and b, the printing direction storage section 17 is cleared to "0" (forward movement), the content Xs of the data storage address storage section 15 and the content Xe of the data retrieval address storage section 16. are each initialized to the address corresponding to the left end of the print string. Then,
The given print data is stored in the print buffer at the address set in the data storage address storage section 15 (step C). Thereafter, 1 is added to the content Xs of the data storage address storage section 15 (step d), and the above cycle is repeated until a print command is received or the print buffer is full, and the print data is stored in the print buffer. Then, when a print command is received or the print buffer becomes full, the print routine is executed. At the start of execution of this print routine, the carriage is at the home position located at the left end of the movement stroke, and the print head 1 corresponds to the left end of the print row on the print paper 3. Here, first, the contents Xc of the data retrieval address storage section 16
is read, and data having this XC as an address is read from the print buffer (step e). And step f.

As shown in g, the content Ps of the print direction storage unit 17 is read, and on condition that the content Ps is 0, that is, the carriage moves forward, a switching signal is given to the multiplexer 18, and the print head 1 is moved via the first driver 19. The first heating element 5 located on the rear side in the direction is energized (step h). As a result, the ink on the ink ribbon 2 is melted and transferred to the printing paper 3.

Thereafter, the carriage is advanced one dot to the right (step 1), and 1 is added to the content Xe of the data read address storage section 16 (step 1).

The above cycle is repeated until all the print data in the print buffer is printed, and then the storage content Ps of the print direction storage section 17 is inverted to "1" (in step 1), and the data storage address storage section is 15 and the contents Xs and Xe of the data retrieval address storage section 16 are initialized to addresses corresponding to the right end of the print string (step m). In this state, the carriage has moved to the movement limit device on the right. Next, one line of print data is stored in the print buffer again. In this case, the content P of the printing direction storage section 17
Since s is "1", as shown in step n, by subtracting the content XS of the data storage address storage section 15 by 1, the print data is arranged in the reverse direction in the print buffer. After storing the print data, the print routine is executed again, and here the memory contents of the print direction storage unit 17 are “1”.
” and the carriage moves backward, so as shown in step 0, a switching signal is given to the multiplexer 18 to switch the second
The second heating element 6 located on the rear side in the direction of movement of the print head 1 is energized via the driver 20 (step 0).
. As a result, the 1' ink of the ink ribbon 2 is melted and transferred to the printing paper 3. Thereafter, the carriage is advanced one dot to the left (step p), and 1 is subtracted from the content Xs of the data read address storage section 16 (step q).
). The above cycle is repeated until all the print data in the print buffer is printed, and the contents of the print direction storage section 17 are
s is inverted to rOJ (step r), and the contents Xs and Xe of the data storage address storage section 15 and the data retrieval address storage section 16 are initialized to the address corresponding to the left end of the print string to the current state. return.

As described above, according to this embodiment, the first heating element 5 is energized during the forward motion when the carriage moves to the right, and the second heating element 6 is energized during the backward motion when the carriage moves to the left. Therefore, regardless of whether the carriage moves forward or backward, the heating element 5 or 6 on the rear side in the direction of movement of the print head 1 is selectively energized. The first heating element 5 of the heel 1 is formed closer to the left side of the print head 1, and the second heating element 6 is formed closer to the right side of the print head 1. Therefore, each heating element 5, The time required for the ink ribbon 2 to separate from the print paper 3 after the ink on the ink ribbon 2 is melted and transferred to the print paper 3 by the energization at step 6 can be shortened regardless of the direction in which the print head 1 moves. can.

As a result, the printing quality can be made uniform regardless of the moving direction of the print head 1, and the above-mentioned time can be made sufficiently short, so that the porous layer 10 of the ink ribbon 2 is not peeled off from the base film 9. This makes it possible to reliably prevent the multi-ink ribbon from losing its advantage of being reusable. Furthermore, since the multi-ink ribbon can be used repeatedly in this way, printing costs can be reduced, and since printing is performed in both directions, the printing speed can of course be sufficiently improved.

[Effects of the Invention] As described above, the present invention provides two rows of heating elements located on both sides of the printing head in the direction of movement thereof, and the heating elements on the rear side are energized according to the direction of movement of the printing head. As a result, it is possible to perform bidirectional printing with uniform print quality using a multi-ink ribbon, which is an excellent effect.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is an overall block diagram, Fig. 2 is a perspective view of the print head, Fig. 3 is a plan view of the print head in the printing state, and Fig. 4 is a diagram of the ink ribbon. The sectional view and FIG. 5 are flowcharts. In the drawings, 1 is a print head, 2 is an ink ribbon, 3 is printing paper, 5 and 6 are first and second heating elements, 10 is a porous layer, and 18 is a multiplexer (switching means).

Claims (1)

[Claims] 1. An ink ribbon provided with a porous layer impregnated with ink is pressed against a printing paper by a print head having a heating element, and the heating element is energized while moving the print head and the ink ribbon to apply the ink to the printing paper. In the apparatus for transferring onto paper, the print head is provided with two rows of heating elements located on both sides of the print head in the movement direction, and when the print head moves forward and backward, A thermal transfer printer characterized in that a switching means is provided for switching so that each of the heating elements on the rear side is energized.