JP2863284B2 - Thermal head array control circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control circuit for a thermal head array used in a thermal recording apparatus.

[Prior Art] FIG. 1 is a connection diagram showing a configuration of a thermal head array, in which (1) is a power supply, (2) is an A-phase power supply,
(3) is a B-phase power supply, (41), (42), and (43) are backflow prevention diodes, (5) is a heating resistor, (61),
(62), (63) and (64) are grounding switches, respectively.
These switches are constituted by ICs together with their control circuits, but are shown as switches in FIG. 1 to represent their functions. (71), (72) and (73) are power supply side lead conductors, and (81), (82), (83) and (84) are ground side lead conductors.

In the drawing, portions indicated by i, j, k, l, m, and n are the respective portions of the heating resistor (5), each constituting one thermal head.

For example, when heating the thermal head indicated by j, the power supply (1) is connected to the A-phase power supply (2), and the switch (62) is closed to connect the lead conductors (71)-(8
The current flows in 2), and the thermal head j is heated.

FIG. 3 is an operation time chart showing the heating control of the thermal head array. In FIG. 1, the switch (6
1), (62), (63), (64)
The shift register includes a shift register, a latch, and a driver. A signal having a logical bit pattern corresponding to opening and closing of a switch is arranged in the shift register. The latch latches a bit pattern of the shift register at the time of input of the load signal. In the driver, the bit logic of the corresponding latch is "1"
In this case, the connected ground-side lead conductor is grounded for a time determined by the strobe signal.

The clock shown in FIG. 3 is a clock signal for arranging data in the shift register.
Is the data of the switch to be grounded when the A-phase power is applied,
Indicates data of a switch to be grounded when the B-phase power is applied. Latches a and b indicate the load signal input times, respectively, and strobe a and strobe b indicate the latches a and b, respectively.
7 shows a strobe signal corresponding to the latch b.

When the control as shown by the latch a is performed, the time (t3)-(t5) (hereinafter referred to as the AB-phase time) from the end of the application of the A-phase power to the start of the application of the B-phase power is determined by the latch b. Is shorter than the AB interphase time (t10)-(t11). AB
If the inter-phase time is short, the adjacent thermal head is heated by the B-phase power supply before the temperature of the portion of the thermal head heated by the A-phase power supply is not sufficiently lowered. In such a case, the heating time is adjusted in consideration of the heating history,
The size of the points thermally recorded by the thermal head having any heating history must be controlled to have the same size.

However, increasing the AB interphase time will generally decrease the printing speed. On the other hand, a time for updating the data of the shift register is inserted between the time of applying the B-phase power and the time of applying the next A-phase power, so that the heating history does not need to be considered as much as the time between the AB phases.

The present invention relates to a control circuit for controlling a heating time in consideration of a heating history. However, since the control circuit itself uses a conventional circuit, description thereof is omitted, and how the heating history and the heating time are related. It will be described how to attach.

[Problems to be Solved by the Invention] Since the above-described conventional thermal head array control circuit is configured and operates as described above, the relationship between the heating history and the heating time is too complicated to be practical. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has as its object to obtain a relatively simple and practical control circuit for a thermal head array in which a relationship between a heating history and a heating time is introduced.

[Means for Solving the Problems] In the control circuit of the thermal head array according to the present invention, the influence when the A-phase power is applied remains until immediately after the B-phase power is applied. The heating history and the heating time are assumed to not remain until the next A-phase power application, and that only the thermal heads adjacent to each other affect each other, and the thermal heads farther away do not affect each other. I decided to simplify the relationship.

[Action] The heating history is divided into five stages, and an appropriate heating time for each stage is set by experiments.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is an explanatory diagram showing each stage of the heating history in the first example. In the figure, (62), (63), j, k, l, and m indicate the same parts as those in FIG. , "1" written in each row means that the switch is closed, that is, the thermal head is energized,
"0" means that the switch is open.

The upper part of each section (a) to (h) shows application of the A-phase power, and the lower part shows application of the B-phase power immediately thereafter. (R) to (R) are A
In this case, the application of the phase B power before the application of the phase power is ignored as the heating history.

In the case of (a), k and l heated simultaneously affect each other, and j becomes k and m
Affects l. In this case, both the switches (62) and (63) are closed in the A phase and the B phase. In (b), the switch (62) is closed in A and B phases, the switch (63) is open in A phase and closed in B phase, and in (c), the switch (63) is closed in A and B phases. The switch (62) opens in phase A and closes in phase B. In (d), only the currents k and l that are energized at the same time affect each other, and when the A-phase power is applied, the adjacent thermal head is not heated. In (e) and (f), there is only the influence of the adjacent thermal head when the A-phase power is applied, and in (g) and (h), there is no such thermal head. On the other hand, when the A-phase power is applied, the thermal heads i and j that are simultaneously energized only in the case of (i) affect each other (nu) and in the case of (ru), there is no mutual effect.

Also, regarding the heating history of FIG. 2, (b) =
(C), (d) = (li), (e) = (he), (g) =
Since (h) = (nu) = (r), (b) is the first career, (b) is the second career, (d) is the third career, (e)
By setting the appropriate energizing time experimentally for each history with the fourth history as the fifth history and the fifth history as the fifth history, and controlling so as to reach the determined energizing time, the thermal history of any heating history can be obtained. Appropriate thermal recording results can also be obtained for the head.

[Effects of the Invention] As described above, the present invention has an effect that a control circuit for a thermal head array that performs practical control by simplifying the relationship between the heating history and the heating time can be obtained.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing a configuration of a thermal head array, FIG. 2 is an explanatory diagram showing a heating history in FIG. 1, and FIG. 3 is an operation time chart showing heating control of the thermal head array. 1 ... power supply, 2 ... A phase power supply, 3 ... B phase power supply, 41, 42,
43: Backflow blocking diodes, 5: Heating resistors, 61, 62, 63, 64: Ground switches, 71, 72, 7 respectively
3. Lead conductors on the power supply side, 81, 82, 83, 84 lead conductors on the ground side. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] A plurality of linear heating resistors arranged at substantially equal intervals and connected to the linear heating resistors, respectively.
A plurality of B-phase power supply lead conductors respectively connected to the linear heating resistor at a substantially intermediate position between each of the A-phase power supply lead conductors and the A-phase power supply lead conductors;
A plurality of ground-side lead conductors respectively connected to the linear heating resistors are provided on the substrate at a substantially intermediate position between the phase-phase power supply lead conductor and the B-phase power supply lead conductor adjacent to the A-phase power supply lead conductor. The two regions of the linear heating resistor divided by each A-phase power supply lead conductor and the ground-side lead conductors on both sides of the A-phase power supply lead conductor are each used as a single A-phase heat generation recording element. The two regions of the linear heating resistor divided by each B-phase power supply lead conductor and the ground-side lead conductors on both sides of the B-phase power supply lead conductor are each a single B-phase heat generation recording element. An A-phase heating recording element is arranged on both sides of two continuous B-phase heating recording elements. Each of the A-phase power supply lead conductors is connected to a power supply, and a designated ground-side lead conductor is grounded. Lead for each A phase power supply A-phase printing operation for collectively printing the designated recording elements of the group of A-phase heating recording elements connected to the conductors, connecting each B-phase power lead conductor to the power supply and grounding the designated ground-side lead conductor Then, the B-phase printing operation for printing all the designated recording elements of each B-phase heating recording element group collectively is performed in this order, and the printing operation for all the heating recording element groups is performed. A control circuit of the thermal head array, which is used immediately before printing the two consecutive B-phase heating recording elements.
In a control circuit of a thermal head array configured to consider the printing history of the A-phase heating recording elements on both sides of the two consecutive B-phase heating recording elements by the phase printing operation, two continuous B-phase heating recording elements are provided. When printing is performed at the same time, the two consecutive B
When both the A-phase heating recording elements on both sides of the phase-heating recording element are printing, the first history is used, and when two consecutive B-phase heating recording elements are printed simultaneously, in the immediately preceding A-phase printing operation, The two consecutive B's
When one of the A-phase heating recording elements on both sides of the phase-heating recording element is printing, the second history is used. When two consecutive B-phase heating recording elements are printed simultaneously, the immediately preceding A-phase printing is performed. In operation, the two consecutive B's
When none of the A-phase heating recording elements on both sides of the phase heating recording element is printed, the third history is used. When one of two continuous B-phase heating recording elements is printed, the immediately preceding A-phase heating recording element is printed. In the printing operation, when the A-phase heating recording element adjacent to the recording element to be printed out of the two consecutive B-phase heating recording elements is printing, the fourth history is defined as the fourth career. The one that does not belong to any of the third and fourth careers is referred to as a fifth career, and the two successive ones described above are arranged in the order of the fifth, fourth, third, second, and first careers so as to shorten the energization time. A control circuit for a thermal head array, wherein the control circuit is configured to perform a printing operation of a B-phase heating recording element.