JPH067644Y2 - Printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a printing apparatus having a memory for storing a video signal.

<Outline of the Invention> The present invention is a printing apparatus having a memory for storing a video signal, detects the horizontal scanning frequency of the input video signal, and changes the clock frequency of the AD converter according to the frequency to detect the input video. By digitally converting the signal and storing it in a memory, it is possible to perform printing with a correct aspect ratio even with video signals having different horizontal scanning frequencies.

<Prior Art> Conventionally, even when the horizontal scanning frequency of the input video signal is different, AD conversion is performed with the same sampling clock, the image is stored in the memory, and then the image is printed.

<Problems to be solved by the device> Since the horizontal scanning frequency is different between the personal computer image and the NTSC image, the circularity (aspect ratio) is distorted when AD conversion is performed with the same clock and the result is stored in the memory.

<Means for Solving the Problems> In the present invention, the horizontal frequency of the input video signal is detected, and the clock frequency of the AD converter is changed according to the frequency.
The input video signal is digitally converted and stored in the memory.

<Operation> PC images and NTSC images can be automatically distinguished and stored according to the aspect ratio (aspect ratio).

<Example> FIG. 1 shows a block diagram.

The still image video signal is input to the horizontal frequency detection circuit 1, the horizontal scanning frequency of the video signal is determined, and the information is input to the CPU 2. The CPU 2 sets and outputs the frequency division ratio to the sampling clock generation circuit 4 based on the information from the horizontal frequency detection circuit.

The clock 1 determined by the frequency division ratio is input from the sampling clock generation circuit 4 to the A / D converter 3 and the print control circuit 5.

Further, the video input is converted into a digital amount by the A / D converter 3 at the timing of the clock 1 and the information is input to the print control circuit 5.

The print control circuit 5 can print by generating a control signal for the thermal head 6 based on the digital information of the image and energizing the thermal head 6.

<Effects of the Invention> Even when the horizontal scanning frequency of the still image input video signal is different, the difference can be automatically detected, and the division ratio data can be freely set and output as needed. It is possible to print with the correct aspect ratio at any time according to the characteristics of.

[Brief description of drawings]

 FIG. 1 is a block circuit diagram of an embodiment of the present invention.

Claims (1)

[Scope of utility model registration request] 1. A for digitally converting a still image input video signal
A printing apparatus comprising a D converter and a sampling clock generating means for generating a sampling clock for determining the AD conversion timing of the AD converter, wherein a horizontal scanning frequency for detecting the horizontal scanning frequency of the still image input video signal is detected. Scanning frequency detecting means, and setting means for setting the dividing ratio data of the sampling clock based on the detection signal from the horizontal scanning frequency detecting means, the dividing ratio data set by the setting means,
An image printing apparatus characterized in that a frequency of a sampling clock is variable by dividing an original oscillation clock of the sampling clock generating means.