JPH02178049A - Video printer - Google Patents

Abstract

PURPOSE:To make adjustment of an image easy in terms of density and contrast by changing at least, any of an upper reference potential or a lower reference potential of an A/D converter which quantizes an image signal while such a reference potential is interlocked to a volume control attached to the outside of a main unit. CONSTITUTION:Signals from volume controls 101, 102 for image quality adjustment of a user attached on the outside (front panel and other appropriate parts) of the main unit of a video printer, are converted by impedance conversion circuits 103, 104. After this, an upper reference potential (+Vref) and a lower reference potential (-Vref) for quantization of an A/D converter 105 are controlled. Then an entered image signal 110 is subjected to A/D conversion and the converted signal is connected to a printing device 106. A non-linear property transformation device can be installed between 101 and 103, or between 102 and 104.

Description

[Detailed description of the invention] [Industrial application field 1 Regarding video printers.

[Conventional technology 1] Conventionally, in a circuit that changes the contrast image quality once according to the user's adjustment using a volume placed outside the main unit (e.g. on the front panel), the amplification rate of an analog amplifier is conventionally changed. The video signal inside and after the tank was converted into A/D.

[Problem to be Solved by the Invention 1] Therefore, at least one amplifier is required, resulting in a large circuit scale. An object of the present invention is to easily adjust the image quality of density and contrast.

[Means to solve the problem] Polyneem electrical signals attached to the outside of the main body.

Upper group 4 of A/D converter! - Adjust the image quality of density and contrast by directly connecting to the input terminal of the potential or lower reference potential.

[Example of implementation] In Fig. 1, a polynym l for user's image quality adjustment attached to the outside of the video printer body (front panel, etc.)
ot, 102 signal to impedance conversion circuit 103,
After conversion in step 104, the upper reference potential (+'Jref) and lower reference potential (-Vre) for quantization of the A/D converter 105 are
f).

After A/D converting the input video signal 110, the printing device 1
Send to 06.

Further, a characteristic converter having nonlinear characteristics may be inserted between 101 and 103 or between 102 and 104.

[Effect of the invention j] The present invention inputs a video signal and performs analog/digital conversion (
In an A/D conversion circuit that performs A/D conversion (hereinafter referred to as A/D conversion), a reference potential on the upper side of the A/D converter that quantizes the video signal,
Or the lower group d! Since it is configured to change at least one of the potentials in conjunction with a volume attached to the outside of the main unit, image quality adjustments for seismic intensity and contrast can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a video blink of the present invention.

Claims (1)

[Claims] Input the video signal and perform analog/digital conversion (hereinafter referred to as A/
In an A/D conversion circuit that performs D conversion), at least either the upper reference potential or the lower reference potential of the A/D converter that quantizes the video signal is connected to a volume mounted outside the main body. A video printer that is characterized by interlocking changes.