JPS60257656A - Printer control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a print control circuit for an image printer, and particularly to a printer control system suitable for performing multicolor overprinting in a full-color printer or the like.

[Background of the invention]

In a thermal transfer type printer, when trying to obtain a full-color print image, the configuration is as shown in FIG. This can be obtained by heat-compression bonding and overprinting, but in order to eliminate color shift and image distortion, it is necessary to make sure that the printing positions of the dot rows 6 do not shift as shown in Figure 2 after three printings. It is necessary that the pitch P of each dot row be constant.

Note that d indicates the print start position. For this reason, it is necessary that there be no slip between the drum 1 around which the recording paper 2 is wound and the motor 5 that drives it, and that the rotation angle of the drum 1 and the rotation phase of the motor 5 are always constant. A high-performance pulse motor is used as the drive motor 5, which is one of the causes of high cost. If a pulse motor is not used, a magnetic, optical, etc. encoder (not shown) is directly connected to the drum shaft to detect the rotational position of the drum, and the entire dot row is printed based on the position signal, and the printing start position d is
and pitch P are always kept constant, which is one of the causes of increased cost.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive printer control system that detects the rotational position of a drum in a simple manner.

[Summary of the invention]

If a constant speed motor with a frequency generator (hereinafter abbreviated as FG) is used as the drum drive motor, and the drive motor and drum are connected using a gear or other non-slip structure,
Since the rotation angle of the drum and the FG phase of the drive motor match, if all FG pulses are counted to determine all print positions of the dot row, there is no need to use all pulse motors or add a special position detection encoder to the drum. Overprinting without printing deviation is possible. The present invention is based on such a principle.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described with reference to the same sounds. FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, 5 is a constant speed motor, 7 is a motor control circuit, 8 is a frequency generator (hereinafter abbreviated as FG) that generates a signal proportional to the rotation of the shaft for constant speed control, and 9 is a signal generator that instructs to start printing. It is sufficient as long as it is a container and indicates that the recording paper always comes to the same relative position when it makes one rotation (one rotation of the drum).

10 is a gate circuit which cuts off the FG80FG pulse until the signal from 9 is generated. 11 is an FG pulse counter, which in this example is a frequency divider. Reference numeral 12 denotes a control circuit for the thermal head, and when the signal from the counter 11 rises (or falls), the thermal head 16 is energized for a time or power according to image information at that location as a reference.

FIG. 4 is a time chart of signals of each part in FIG.

(A) to (D) in the figure are (A) to (A) to (D) in Fig. 5.
Corresponds to (D).

The circuit operation of FIG. 6 will be better understood by referring to FIG. 4 in its entirety.

If configured as described above, the FG of the constant speed motor for driving the drum and the drum rotational position sensor can all be used in common, which is very advantageous in terms of cost.

〔Effect of the invention〕

According to the present invention, there are not only the aforementioned cost reduction effects but also the following advantages.

If you try to obtain the signal to start printing a dot row directly from the drum axis, in the case of high-resolution printing where one screen consists of hundreds of dot rows, the number of dot rows in the drum rotation will be the same as the number of dot rows or an integral multiple thereof. Signals that occur at equal rotation angles are required. On the other hand, in the system of the present invention, the reduction ratio between the single-frame motor and the drum is usually several tens to hundreds, so the total number of FG pulses generated during drum rotation can be easily selected to be very large. Position detection accuracy is improved. In addition, in the explanation of the embodiment, the motor is a constant speed motor using FGk, but since it is only necessary that the rotational phase of the motor and the rotational phase of the drum match, it is especially important if the FG is directly connected to the motor shaft. It is understood that it does not have to be fast.

[Brief explanation of drawings]

Fig. 1 is a side view schematically showing a conventional transfer type printer, Fig. 2 is an explanatory diagram showing a row of printed dots on recording paper, and Fig. 3 II.
4 is a block diagram showing one embodiment of the present invention, and FIG. 4 is a time chart of various signals in FIG. 5. Explanation of symbols 1...Rotating drum 2...Recording paper 6...Transfer paper 4...Thermal head 5...Drive motor 6...Dot row 7...Motor control circuit 8-pin frequency generator? Printing start number digit generator 10, gate circuit 11, counter 12, thermal head control circuit 15, thermal head representative patent attorney Akio Takahashi No. 1 Old No. 1? l $3 Figure 4 (cut 1 -

Claims (1)

[Claims] 1) means for counting the number of pulses from a frequency generator coupled to the shaft of a motor that drives the drum in a printer that prints pixel rows at regular intervals on a recording medium mounted on a rotating drum; A printer control system that is fully equipped with means for determining the printing position for each pixel column based on the results.