JPS6354279A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To obtain a picture surface free from the greasing and uneveness in density of printing paper caused by the exchange of a cassette, by a method wherein printing operation is stopped before the printing of a new line is started by detecting that the remaining amount of an ink ribbon has come to a specific length longer than the length of one line of the maximum printing width. CONSTITUTION:The control unit 20 is provided, in which an ink ribbon cassette 11 is installed to the carriage 10 of a printer, and the printing drive part 19 such as the carriage 10, a printing head 12, etc. is controlled based on the output of a ribbon remaining amount sensor 18. The ribbon remaining amount sensor 18 consisting of touch-type switch sheet, extending outward in the radiation direction from a little outside of the outer surface of the first ribbon core 15 is provided on the upper surface of the bottom wall 11a of the cassette 11. The length of the part 17a of an ink ribbon 17 existing inward from the inner end 18a of the sensor 18 is a specific length longer than the length of one line for the maximum printing width. Until the remaining amount becomes the length of a ribbon end, the sensor 18 turns on, and the printer is in a printable state. When the remaining amount has become the length of the ribbon end, the sensor 18 turns off and the printer comes to be in a tape end state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to thermal transfer printers that use replaceable ink ribbon cassettes mounted on a carriage.

Conventional technology and its problems Traditionally, this type of thermal transfer printer uses a one-time ink ribbon that can only be used once.
When you print to the end of the ribbon and reach the ribbon end, you need to replace it with a new cassette. In order to prevent the printer from continuing printing even when the ribbon end is reached, the printer often stops printing when a ribbon end sensor detects the ribbon end. Then, when the operator replaces the cassette and gives an instruction to resume printing, printing resumes.

However, in conventional printers, due to the size constraints of the ink ribbon cassette, the length of the ink ribbon between the print head and the ribbon end sensor, that is, the remaining ink ribbon when the ribbon end is detected, is the maximum print width of one line. The length had to be shorter than that required for printing minutes, and as a result, when the ribbon end was detected, the printing operation had to be stopped even in the middle of a line.

On the other hand, in thermal transfer printers, background smudges are likely to occur when the ink ribbon rubs against the surface of the printing paper, and background smudges occur particularly when printing starts, when the head stops, and when the amount of ink ribbon remaining is low. It tends to happen sometimes.

In conventional printers, printing is performed until the remaining amount of the ink ribbon becomes very small, which tends to cause background smudges. In addition, since printing is stopped and restarted in the middle of a line, scumming is likely to occur in the middle of a line, and printing is stopped in the middle of a line and resumed after a while while the cassette is replaced. Therefore, density unevenness tends to occur in the middle of a row. As a result, the appearance of the printed surface becomes poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer blink that solves the above-mentioned problems and is less likely to cause scumming or density unevenness on printing paper due to cassette replacement.

Means for Solving the Problems The thermal transfer printer according to the present invention has a ribbon remaining amount detection system that detects when the remaining amount of ink ribbon in the ink ribbon cassette reaches a predetermined length that is longer than the length of one line of the maximum print width. and a control means for stopping the printing operation before starting printing of a new line after the remaining amount of the ink ribbon reaches the predetermined length.

The printing operation always stops before starting printing of a new line after the remaining amount of ink and ribbon reaches the predetermined length, and does not stop in the middle of a line. Therefore, even if the cassette is replaced, scumming or density unevenness is less likely to occur in the middle of a row. Furthermore, since the amount of ink ribbon remaining when replacing the cassette can be increased, background stains are less likely to occur on the printing paper.

Embodiment FIGS. 1 and 2 show an ink ribbon cassette (11) mounted on a carriage (10) of a thermal transfer printer.
) is shown.

The carriage (10) is provided with a print head (12), an ink ribbon take-up shaft (13), etc. that rotates only when the carriage (10) moves in the printing direction.

Cassette core (1) fixed to one side of the cassette (11)
A first winding core (15) is rotatably attached to the winding shaft (15) of the carriage (10) on the opposite side.
3) and is provided with a second adhesive core (16) which rotates therewith. A single ink ribbon (17) having one side of the base coated with ink is wound around these ribbon cores (15016). In a new cassette (11), most of the ribbon (11) is wound around the first ribbon core (15) and its diameter is at its maximum. When a printing operation is performed, the ribbon (11) is fed out from the first ribbon core (15 mm) and transferred to the second ribbon core (15 mm).
6), the diameter of the ribbon (17) on the first ribbon core (15) gradually decreases.

A ribbon remaining sensor (18) is provided on the top surface of the bottom wall (lla) of the cassette (11), and is comprised of a touch-type switch sheet extending radially outward from slightly outside the outer surface of the first ribbon core (15). Sensor (18)
The ink ribbon (17) inside the inner end (18a) of
Part (17a) (hereinafter referred to as ribbon end part)
The length is a predetermined length longer than the length of one line of maximum print width (hereinafter referred to as ribbon end length). Until the remaining amount of the ink ribbon (17) on the first ribbon core (15) reaches the ribbon end length (,t,, sensor (18)
) Since the ink ribbon (11) is placed on top of the ink ribbon (11), its pressure turns on the sensor (18), making the output ready for printing. Then, the first ribbon core (
15) When the remaining amount of the upper ink ribbon (17) reaches the ribbon end length, there is no more ribbon (17) on the sensor (18), so the sensor (18) turns off and its output becomes the tape end state. . Although not shown, there is a space between the carriage (10) and the cassette (11).
A connector is provided for taking out the output of the sensor (18).

FIG. 3 schematically shows part of the electrical configuration of the printer,
The printer includes a control device (20) that controls a print drive unit (19) such as a carriage (10) and a print head (12) based on the output of a ribbon remaining amount sensor (18).

The control device (20) includes a microcomputer, and controls the printing operation in the following manner, for example: The till@ device (20) starts printing a new line after finishing printing one line. The sensor (
Check the output of step 18), and if printing is possible, start printing a new line. If the ribbon has already reached the end state, the printing operation is stopped before starting printing of a new line, and an alarm is issued to notify that the cassette needs to be replaced.

The No. 11 printer H (20) can also tilt the printing operation as follows.

That is, the control device (20) constantly monitors the output of the sensor (18) during the printing operation, and when this output reaches the ribbon end state, it finishes printing that line and prints a new one. Stops printing before starting printing a line.

In any of the above cases, even if the ribbon end condition occurs immediately after starting printing a new line, the ribbon end length is longer than the length of one line with the maximum print width, so printing of that line will not be completed. Printing will never become impossible. Therefore, the printing operation can always be stopped before starting printing of a new line, and will not be stopped in the middle of a line. Therefore, even if the cassette is replaced, background stains and density unevenness are less likely to occur in the middle of a row. Furthermore, by appropriately selecting the length of the ribbon end, the amount of ink ribbon remaining when replacing the cassette can be increased, so that scumming is less likely to occur.

The ribbon remaining amount sensor is not limited to the one in the above embodiment, and can be modified as appropriate.

FIG. 4 shows a modification of the ribbon remaining amount sensor. This sensor (21) includes, for example, a reflective photosensor attached to the lid (22) of the printer. This sensor (21) is located above the ribbon (17) slightly outside the outer surface of the first ribbon core (15) of the cassette (11) on the carriage (10) when starting printing a new line. The portion of the ribbon (17) inside the sensor (21) is a tape end portion (17a) having the tape end length. The top wall (11b) of the cassette (11) is transparent or has a hole at a position corresponding to the sensor (21), and the top surface of the bottom wall (11a) of the cassette (11) below the sensor (21) is Colored with long reflectance. And the first ribbon core (15)
Until the remaining amount of the upper ink ribbon (17) reaches the ribbon end length, the light emitted from the sensor (21) is reflected by the upper surface of the ink ribbon (17), which has poor reflectivity, so the sensor (21) It is turned off and its output is ready for printing. When the remaining amount of the ink ribbon (11) on the first adhesive ribbon core (15) reaches the ribbon end length, the light emitted from the sensor (21) is reflected by the top surface of the bottom wall (11a) of the cassette (11), which has a long reflectance. Since it is reflected back, the sensor (21) is turned on and its output becomes a ribbon end state. The relaxation is the same as in FIG.

5 and 6 show other variations of the ribbon remaining amount sensor. This sensor (23) has a detection head (24) that detects a substance to be detected such as a conductive substance or a magnetic substance.
). This head (24) is connected to the carriage (1
0) and is in contact with the ink ribbon (17). In the case of FIG. 5, a detection substance layer (26) is formed on the back surface of the base (25) of the ribbon end portion (17a) of the ink ribbon (17). , also the sixth
In the case of the figure, the ink layer (27) of the ink ribbon (17)
The ribbon end portion (27a) contains the substance to be detected, and the remaining portion (27b) does not. In either case, when the head (24) detects the substance to be detected, it can be detected that the remaining amount of the ink ribbon (11) has reached the ribbon end length.

In the case of FIG. 5, the detection substance layer may be formed in a portion other than the ribbon end portion (17a). Furthermore, in the case of FIG. 6, the ribbon end portion (27a) of the ink layer (27) may not contain the substance to be detected, but may be contained in the remaining portion (27b).

In addition, a color ink ribbon (an ink ribbon in which three colors of yellow, magenta, and cyan, or four colors of these plus black are applied in series on one base, separated by color identification markers) is used. In the case of a printer capable of color thermal transfer printing, in addition to the ribbon remaining amount sensor (1B) (21023), a color identification sensor similar to a conventional ribbon end sensor is installed to identify colors based on the type of color identification marker. (28) is provided. However, in the case of a printer capable of only black thermal transfer printing using a black ink ribbon, such a color discrimination sensor (28) is not necessary.

Effects of the Invention Since the thermal transfer printer according to the present invention has the above-described configuration, the printing operation does not stop in the middle of a line, and the remaining amount of the ink ribbon can be appropriately lengthened. Furthermore, since the remaining amount of the ink ribbon can be made appropriately long, background smudges are less likely to occur, and since the printing operation does not stop in the middle of a line, background smudges and density unevenness are less likely to occur in the middle of a line. , it is possible to obtain a long printing surface of high quality with no background smudge or PC degree unevenness.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a partially cutaway plan view of a carriage in which an ink ribbon cassette is attached, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a thermal transfer A block diagram schematically showing a part of the electrical configuration of the printer, FIG. 4 is a drawing corresponding to FIG. 2 showing a modification of the ribbon end detection means, and FIGS. 5 and 6 show a modification of the ribbon end detection means. It is a principal part top view which shows the modification of . (11)... Ink ribbon cassette, (17)...
Ink ribbon, (18) (21) (23)... Ribbon remaining amount sensor, (20)... Control device. Patent applicant: Konishiroku Photo Industry Co., Ltd.

Claims (4)

[Claims] (1) Ribbon remaining amount detection means for detecting when the remaining amount of ink ribbon in the ink ribbon cassette reaches a predetermined length longer than the length of one line of the maximum print width; and a control means for stopping the printing operation after the printout is reached and before starting printing of a new line. (2) The control means checks the output of the ribbon remaining amount detection means from the end of printing one line until the start of printing a new line, and determines whether the remaining amount of the ink ribbon has already reached the predetermined length. The thermal transfer printer according to claim 1, wherein the thermal transfer printer stops the printing operation before starting new printing. (3) The control means constantly checks the output of the ribbon detection means during the printing operation, and when the remaining amount of the ink ribbon reaches the predetermined length described above, prints on that line and then starts a new line. The thermal transfer printer according to claim 1, wherein the printing operation is stopped before starting printing. (4) When the control means stops the printing operation after the remaining amount of the ink ribbon reaches the predetermined length and before starting printing of a new line, it issues an alarm informing that the cassette needs to be replaced. A thermal transfer printer according to any one of claims 1 to 3.