US 2001/0012463 A1Published application

Thermal line printer and printing method therefor

AssigneeFuji Photo Film Co., Ltd.

InventorHiroshi Fukuda

Life of this patent

Estimating the term…

Loading patent…

Abstract

There is disclosed a thermosensitive line printer, wherein a heating element array of a thermal head is pressed on a thermosensitive recording paper at a distance L2 from a nipping position by a pair of conveyer rollers, and is driven to record an image frame line by line from a print starting end, as the recording paper is conveyed by the conveyer rollers in a direction from the thermal head to the conveyer rollers. Based on image data of an upper zone of an image frame that is to be recorded around the distance L2 from the print starting end if the image frame is recorded from its top side, an image analyzer calculates a first estimation value that represents conspicuousness of potential density deviation in the upper zone that could be caused by a thermal deformation of the thermosensitive recording paper at the print starting end if the image frame is recorded from the top side. The image analyzer calculates a second estimation value based on image data of a lower zone that is to be located at the distance L2 from the print starting end if the image frame is recorded from its bottom side. If the first estimation value is smaller than the second estimation value, the image frame is recorded from the top side, and vise versa.

Claims12

Dependent claims

A thermal line printer comprising:

a pair of conveyer rollers for nipping and conveying a recording paper along a paper transport path;
a thermal head having an array of heating elements arranged transversely to said paper transport path and pressed onto said recording paper at a constant distance from a nipping position by said conveyer rollers, said thermal head being driven based on image data to record an image frame line by line from a print starting end of an image recording area on said recording paper as said recording paper is conveyed by said conveyer rollers in a direction advancing from said thermal head toward said conveyer rollers;
an image analyzer for calculating based on said image data, a first estimation value representative of conspicuousness of potential density deviation said image frame could have in a first zone including a line that is to be recorded at said constant distance from said print starting end if said image frame is recorded from a top side thereof, and a second estimation value representative of conspicuousness of potential density deviation that said image frame could have in a second zone including a line that is to be recorded at said constant distance from said print starting end if said image frame is recorded from a bottom side thereof;
and
a control device for comparing said first and second estimation values to each other and controlling said thermal head to start recording said image frame either from said top side or from said bottom side depending upon said estimation values such that said potential density deviation becomes less conspicuous.

2 more elements

A printing method for a thermal line printer wherein an array of heating elements of a thermal head are pressed onto a recording paper and driven in accordance with image data to record an image frame in an image recording area on said recording paper line by line from a print starting end of said image recording area, as said recording paper is conveyed by a pair of conveyer rollers in a direction advancing from said thermal head toward said conveyer roller pair, said conveyer rollers nipping said recording paper at a constant distance from the pressing position of said heating element array, said printing method comprising the steps of:

calculating a first estimation value representative of conspicuousness of potential density deviation said image frame could have in a first zone including a line that is to be recorded at said constant distance from said print starting end of said image recording area if said image frame is recorded from a top side thereof, based on image data of said first zone;
calculating a second estimation value representative of conspicuousness of potential density deviation said image frame could have in a second zone including a line that is to be recorded at said constant distance from said print starting end if said image frame is recorded from a bottom side thereof, based on image data of said second zone;
comparing said first and second estimation values to each other;
and
controlling said thermal head to start recording said image frame either from said top side when said first estimation value is smaller or from said bottom side when said second estimation value is smaller.

2 more elements

picking up image data of a first line that is to be recorded at said print starting end;
calculating based on tonal levels of said picked up image data an amount of heat energy applied from said thermal head to said recording paper at said print starting end;
deriving from said heat energy amount a deformation amount of said recording paper;
calculating based on said deformation amount a density correction value;
and
correcting recording densities of a line located at said constant distance from said print starting end, in accordance with said density correction value.

3 more elements

Dependencies are inferred from the claim text.