Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-01-29
2001-02-20
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S115000, C347S232000, C347S238000
Reexamination Certificate
active
06191805
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical printer used for forming an image on a record medium such as a photosensitive film or the like, for example, in a color video printer or the like and a printer head used therefor, and more particularly to a printer head which includes luminous lines having luminous dots arranged thereon and in which light exposure is carried out while permitting dot-like light from the luminous lines to be superposed on a record medium, to thereby form an image thereon and an optical printer including such a printer head.
2. Discussion of the Background
The assignee proposed an optical printer which is so constructed that a fluorescent luminous tube acting as a luminous element is used as a printer head to form an image on a record medium such as a photosensitive film or the like. The printer head constituted by the fluorescent luminous tube, as shown in
FIG. 11
, includes a number of luminous dots arranged in two rows in an offset manner. The luminous dots each are formed into a square configuration of sides having a length a. The luminous dots of each of the rows are arranged at intervals a in a main scanning direction. The luminous dots of the rows adjacent to each other are arranged so as to be spaced from each other at pitches P (=a) in the main scanning direction and at a pitch b (=
4
a
) in a sub-scanning direction. The rows are arranged so as to extend in parallel to each other.
The printer heads designated at reference numeral
101
in
FIG. 12
each include a box-like envelope, in which a number of anodes each including a phosphor layer are arranged to form luminous dots. An optical printer shown in
FIG. 12
includes three such printer heads
101
. Luminous dot arrays of each of the printer heads
101
include a main scanning direction defined in a horizontal direction or a direction perpendicular to a plane of
FIG. 12 and a
sub-scanning direction defined in an upward vertical direction or a vertical direction on the plane of FIG.
12
. The luminous dot arrays are arranged in a manner to be parallel to each other at a predetermined interval while keeping positions thereof in the main scanning direction and those in the sub-scanning direction coincident with each other. Dot-like light emitted from the luminous dots of each of the printer heads is directed forwardly in the horizontal direction. The printer heads each are provided on a side thereof facing a substrate with an image-formation optical system
104
constituted of a mirror
102
and a selfoc lens array (SLA)
103
, so that a light path of light emitted from each of the printer heads
101
is perpendicularly shifted in a downward vertical direction. The optical printer also includes red, green and blue color filters R, G and B arranged below the selfoc arrays
103
, respectively. In the conventional optical printer shown in
FIG. 12
, the luminous dots of the printer heads
101
each are made of a ZnO:Zn phosphor, which exhibits a considerably expanded luminous spectrum, so that such an arrangement of the color filters R, G and B permits dot-like light of each of red, green and blue luminous colors to be irradiated onto a record medium
105
which is arranged below the color filters R, G and B. The record medium
105
is arranged so as to be moved in the sub-scanning direction or a lateral direction in
FIG. 12
relatively to dot-like light emitted from each of the printer heads
101
.
During a recording operation, the record medium
105
is moved in the sub-scanning direction relatively to light emitted from the printer heads
101
. Data on an image decomposed into red, green and blue colors are fed to the printer heads
101
corresponding in color thereto, so that the two-row luminous dots of each of the printer heads
101
are driven for luminescence at predetermined timings in synchronism with relative movement of the record medium
105
described above. Such driving permits light emitted from the luminous dots arranged in two rows and in an offset manner to be irradiated in the form of a single straight line parallel to the main scanning direction on the record medium
105
, so that irradiation of light beams from the printer heads
101
to the printer head
101
while being superposed on each other leads to formation of a full-color image on the record medium
105
.
The selfoc lens arrays
103
of the image-formation optical system described above, as shown in
FIG. 13
, form an erected real image of an equi-magnification on the record medium
105
. Thus, dot-like light emitted from the luminous dots forms the image on the record medium
105
without changing a configuration thereof or while keeping the configuration unvaried.
In order to increase the quantity of light in the conventional optical printer or printer heads constructed as described above, it would be considered to increase an anode voltage of the printer head or arrange two or more printer heads of the same luminous color. Unfortunately, an increase in anode voltage of the printer head requires to increase dielectric strength of a driver IC for driving the printer head, leading to an increase in manufacturing cost of the printer head. Also, such an increase in the number of printer heads as described above likewise causes an increase in manufacturing cost. Thus, the approaches each are an obstacle to a reduction in manufacturing cost, resulting in failing to be successfully employed to increase manufacturing cost.
In particular, the optical printer including the printer heads respectively exhibiting red, green and blue luminous colors has a disadvantage that the red luminous color is generally decreased in light quantity or intensity as compared with the green and blue luminous colors, so that a full-color image formed is deteriorated in color balance, leading to a failure in reproduction of natural color. This would be due to the fact that a red color ingredient contained in light emitted from the ZnO:Zn phosphor is reduced in light intensity as compared with the remaining color ingredients.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing disadvantage of the prior art.
Accordingly, it is an object of the present invention to provide a printer head which is capable of increasing intensity of dot-like light irradiated onto a record medium without requiring to increase a drive voltage or the number of printer heads arranged.
It is another object of the present invention to provide a printer head which is capable of increasing intensity of light of a luminous color of which light intensity is relatively reduced such as a red luminous color, resulting in being suitable for use for an optical printer in which a full-color image is formed by means of a plurality of printer heads different in luminous color from each other.
In accordance with one aspect of the present invention, an optical printer head is provided. The optical printer head includes a luminous element including a plurality of luminous dots which have a dimension in a sub-scanning direction increased as compared with that in a main scanning direction and are spaced from each other at predetermined intervals in the main scanning direction. Also, the optical printer head includes a reduction optical system for carrying out irradiation of light emitted from the luminous dots of the luminous element while reducing a dimension of the light in the sub-scanning direction.
Also, in accordance with this aspect of the present invention, an optical printer head includes a luminous element including two luminous dot arrays arranged in parallel to each other at a predetermined interval in a sub-scanning direction. The luminous dot arrays each are constituted of a plurality of luminous dots which have a dimension in the sub-scanning direction increased by a predetermined magnification as compared with that in a main scanning direction and are spaced from each other at identical intervals in the main scanning direction. The luminous dots of the two luminous dot arrays
Morishima Hiromichi
Nakahara Toshiaki
Nakamura Shigetaka
Saito Masao
Shimizu Yukihiko
Futaba Denshi Kogyo K.K.
Le N.
Nguyen Lamson D.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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