JPS5910919B2 - Two-color printing method for serial printers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a two-color printing method for a serial printer such as a dot printer or a line printer 5 that prints sequentially from the start of printing to the end of printing, and is aimed at increasing the printing speed. .

The present invention will be explained below by limiting the serial printer to a dot printer. For example, when printing in two colors, red and black, 10 ink ribbons of red and black are prepared, and the ink ribbon of the color specified by the control code is switched to, and printing is performed in that color.

At this time, the print head, which prints out a predetermined character by hitting the ink ribbon and print paper facing each other against the platen, remains stationary at its print position until the ink printer 15 is completely switched. The ink ribbon switching time is generally longer than the time from printing one digit to printing the next digit. For this reason, each time the designation of a print color changes, the ink ribbon must be switched to perform printing 20, resulting in a problem that the printing speed decreases. In particular, there was a drawback that the printing speed was extremely reduced when the specified color changed frequently within one digit. The present invention has been made in view of the above points, and the present invention will be described below with reference to the drawings of the embodiments, with the 252 printing colors being limited to red and black.

, in the figure, 10 is a random access memory (hereinafter abbreviated as RAM) 30 that stores one line of print data transferred from a computer (not shown), and at the same time a color designation bit is input via a color identification latch 12. I remember.

Reference numeral 14 denotes an address designation counter used when reading out the RAMI0, and AND gates 16 and 18 are connected to its addition input terminal and subtraction input terminal, respectively.

20 is an inverter.

Reference numeral 22 denotes a print direction specifying latch, which is composed of a flip-flop that is set when the print head (not shown) is at the print start end and reset when the print head is at the print end.

Reference numeral 24 denotes a feed speed identification circuit for the print head, which is composed of two flip-flops 26, 28 and four AND gates 30, 32, 34, and 36.

The flip-flops 26 and 28 have color designating bits such as red, black, etc. applied to their set inputs, respectively, during the data transfer. AND gates 30-36 are used to match the output of print direction specifying latch 22 with the outputs of flip-flops 26 and 28. Reference numeral 38 is a speed setting circuit which receives the outputs of the AND gates 30 to 36 and controls and sets the speed of the drive motor 40 as appropriate.

The drive motor 40 reciprocates the print head in the row direction of the printing paper. Reference numeral 42 is an exclusive OR gate that compares the color designation data in the RAMIO with the output data of the "1 side output" of the print direction designation latch 22.

Reference numeral 44 denotes an ink ribbon switching means consisting of a solenoid or the like, which is driven by the output of the "1 side output" of the print direction specifying latch 22 to set one color of the ink ribbon (not shown) at the print position. be.

46 is a timing circuit that generates a print timing pulse signal; 48 is an AND gate that matches the output pulse signal of the timing circuit 46 with the information data of RAMIO and the output of the exclusive OR gate 42; The print head is driven by energizing a solenoid (not shown) or the like.

The input terminal of the AND gate 16 is supplied with a strobe signal sent each time the print head is moved by one digit and the output of the "1 side output" of the print direction designating latch 22. It is assumed that black is printed during forward printing from the starting end to the printing end, and red is printed during backward printing from the printing end to the printing end.

Also, set the color specification bit to "F" or 60, and set red to "1".
- Set black to ゛01. Suppose that it is now detected by a limit switch or the like that the print head is located at the printing position.

As a result, the printing direction specifying latch 22 is set, its "1 side output" becomes 1 (high level), the ink ribbon switching means 44 is driven, and the black ink ribbon is placed at the printing position.In this state, , each time the print head is moved, the address designation counter 14
The print data and color designation bits within are read out, and only black print data is printed.

That is, in the case of red print data, the exclusive OR gate 42
If the input is 1,1'', the output will be 60゛,
Since the AND gate 48 does not open and the AND gate 48 does not open, no red print data is printed. When printing progresses and the print head reaches the end of printing, it is detected by a limit switch (not shown) or the like, and the printing direction designation latch 22 is set.

Therefore, the biasing force of the ink ribbon switching means 44 is released and the ink ribbon is placed in the red printing position. In this state, each time the print head is retracted, the print data and color designation bits in the RAMIO are read out by the address designation counter 14, and only the remaining red print data is printed. The feed speed identification circuit 24 determines the feed speed of the print head as follows, and controls the speed of the drive motor 40 via the speed setting circuit 38.

(1) If the printing code includes both red and black, the printing speed is both forward and backward. (2) If the printing code is only black, the printing speed is fast when moving forward, and the printing speed is high when retreating. (3) When the printing code is only red. , high speed when moving forward, printing speed when moving backward, i.e.
If there is a red print code among the print codes, the flip-flop 26 is set during the data transfer, and when the print head is retracted, the AND gate 30 is matched, and the print speed is set at the time of retraction.

If there is no red print code among the print codes, the flip-flop 26 will remain set, so the AND gate 32 will match when retracting, and a high speed (faster than the printing speed) will be achieved when retracting. Further, if there is a black print code among the print codes, the flip-flop 28 is set, the AND gate 34 is matched during the forward movement, and the printing speed is set during the forward movement.

Further, if there is no black print code among the print codes, the flip-flop 28 remains set, so that the AND gate 36 is matched during the forward movement, and a high speed is achieved during the forward movement. As described above, according to the present invention, only the print data of one color is printed during forward printing, and the print data of the other color is printed during backward printing, so the ink ribbon only needs to be switched once, and printing can be performed easily. The effect of increasing the speed can be achieved.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of a printing device to which the printing method of the present invention is applied. 10...Random access memory (RAM)
, 12... Color identification latch, 14... Address designation counter, 16, 18, 30, 32, 34, 36
, 48...AND gate, 20...Inverter, 22...Print direction designation latch, 24
...Feed rate identification circuit, 26, 28...
・Flip-flop, 38... speed setting circuit,
40... Drive motor, 42... Exclusive OR gate, 44... Ink ribbon switching means.

Claims (1)

[Claims] 1. A dot printer that prints predetermined characters by hitting an ink ribbon and printing paper against a platen using at least one print head that moves back and forth along a printing line, or facing a type conveyor such as a type drum or a type belt. In a serial printer such as a line printer that prints by sequentially driving a plurality of printing hammers provided in the direction from the printing start end as appropriate, the printer is equipped with ink ribbons of two colors, such as red and black, and moves from the printing start end to the printing end. During forward printing, place one color of the ink ribbon, such as black, at the printing position and print with only that one color, and print with the other color of the ink ribbon, such as red, during backward printing from the end of printing to the start of printing. A two-color printing method characterized by placing the printer in one position and printing in the other color.