Optical printer

Details Optical printer Optical printer

1999-12-22

2002-01-29

Adams, Russell (Department: 2851)

Photocopying

Projection printing and copying cameras

Multicolor picture

C355S035000, C355S040000

Reexamination Certificate

active

06342940

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical printer used in an optical recording apparatus such as a stationary and portable printer, copying machine and so on. More particularly, this invention relates to an optical printer constructed so as to write to a recording medium by switching plural kinds of filters.
2. Description of the Invention
In general, the optical printer is provided with a light source comprising a number of delicate light emitting dots arranged linearly and is an apparatus for forming a desired image to the recording medium while moving the light source in the direction crossing at right angles the direction of arrangement of the emitting dots to irradiate the recording medium with dotted light. As the light source is used an elements based on a various kinds of principles of light emission, for example, a fluorescent light-emitting tube, LED and so on.
FIG. 13
is a schematic cross-sectional view showing an outline of the construction of an optical printer used in a conventional optical writing apparatus, for example, a portable color printer and so on.
FIG. 14
is a plan view showing a print head a part of the construction of which is omitted used in the optical printer.
As shown in
FIG. 13
, the print head
100
used in the optical printer can move back and forth relative to sub-scanning direction to a film
102
as a recording medium located at a given position. That is to say, as shown in
FIG. 14
, the print head
100
is guided by a pair of guide shaft
104
,
104
parallel in the sub-scanning direction and further is connected with a wire
108
driven by a motor
106
to move back and forth in the sub-scanning direction. And, the print head
100
comprises a light emitting element (light source)
110
which has a plurality of light emitting dots arranged in the main scanning direction. The light from the light emitting element
110
passes through filters (R, G, B) as described after and forms an image on a film
102
via a reflecting optical element
112
, a life-size optical system
114
, a reflecting optical element
116
.
As shown in
FIG. 13
, three filters R, G, and B of red (R), green (G) and blue (B) are located switchably on the side of the light emitting element
110
which is irradiated with light. As shown in
FIG. 14
, these three filters R, G and B have, respectively, a shape the longer direction of which is the main scanning direction and are in the direction of sub-scanning and mounted to a common frame
118
. The frame
118
is provided with a projection
120
for operating a frame. The projection
120
is retained by a guide bearing
122
and a positioning bearing
124
. The positioning bearing
124
is forced by a spring
126
and engages with one of three notches formed in the projection
120
. The frame
118
is forced by a spring
130
toward a given direction in the direction of sub-scanning. A stopper
132
is provided at a given position on the side of the projection
120
and a reset plate
134
is provided at a given position on the opposite side of the stopper
132
so as to interpose the optical writing head between the stopper
132
and the reset plate
120
. That is to say, when the projection
120
of the frame
118
strikes against the stopper
132
with the movement of the print head
100
, the frame
118
moves to change and the filters (R, G, B) are switched. And, when the optical writing head
100
moves in the direction opposite to the stopper
132
and the reset plate
134
moves a shaft
136
of the positioning bearing
124
, the engagement of the frame
118
by the positioning bearing
124
is released and the frame
118
moves in the direction of the stopper
132
by the spring
130
.
Next, a writing operation to the film
102
according to the aforementioned construction is described with reference to FIG.
15
.
FIG. 15
is a diagram in which the writing operation to the film at the aforementioned print head is illustrated sequentially according to the procedures shown by arrow marks. In
FIG. 15
, arrangements of longitudinal figures shown in (a), (b) and (c) show a filter reset action, an action from the start to the end of the exposure, and a switching action of the filters (R, G, B) after the exposure, respectively. In
FIG. 15
, a mark &Dgr; of the light source
110
shows a position of the light emitting dot line. According to this optical writing head
100
, an image is color-separated into three primary colors of R G B and a full color image is formed by writing an image of each color to a sheet of film one over the other.
As shown in FIG.
15
(
a
), the reset plate
134
moves the shaft
136
of the positioning bearing
124
to the left with the movement of the optical writing head
100
. The frame
118
moves to the right by the spring
130
and is reset at an initial position where the filter R is set at a position where the light emitting element
2
is irradiated with right (mark &Dgr;).
As shown in FIG.
15
(
b
), the optical writing head
100
moves to the right along the direction of sub-scanning in FIG.
15
(
b
). In synchronization with this, the light emitting element
100
is driven by an image signal of R (red). An image of R (red) is formed to the film.
As shown in FIG.
15
(
c
), when the image of R (red) is formed to the film, the projection
120
of the frame
118
strikes against the stopper
132
at the right end in FIG.
15
(
c
) and the frame
118
moves and the filter is switched from R (red) to G (green).
Thereafter, the optical writing head
100
moves to the starting position of exposure on the left side in FIG.
15
(
a
) where reset of the filter is not performed because the reset plate
134
does not contact with the shaft
136
of the positioning bearing
124
. And, similarly to the aforementioned (
b
), the optical writing head
100
moves to the right along the direction of sub-scanning in FIG.
15
(
b
) and, in synchronization with this, the light emitting element
110
is driven by an image signal of G (green) to form an image of G (green) to the film. And, similarly to (
c
), the projection
120
of the frame
118
strikes against the stopper
132
at the right end in FIG.
15
(
c
) to move the frame
118
and the filter is switched from G (green) to B (blue).
Thereafter, the optical writing head
100
moves to the starting position of exposure on the left side in FIG.
15
(
a
) where reset of the filter is not performed because the reset plate
134
does not contact with the shaft
136
of the positioning bearing
124
by controlling a movement distance of the optical writing head. And, similarly to the aforementioned (
b
), the optical writing head
100
moves to the right along the direction of sub-scanning in FIG.
15
(
b
) and, in synchronization with this, the light emitting element
110
is driven by an image signal of B (blue) to form an image of B (blue) to the film. And, similarly to (
c
), while the optical writing head
100
reaches the right end in FIG.
15
(
a
), the filter does not move any more to the left because it has been switched to the extreme left side.
Thereafter the optical writing head
100
moves to the starting position of exposure at (
a
) on the left side in FIG.
15
(
a
) and the reset plate
134
contacts with the positioning bearing
135
to perform the reset of the filter. Thereby, the filter is set again at R (red).
As above described, in the aforementioned conventional optical printer the optical writing head
100
can move in the direction of sub-scanning to the film
102
located at a given position. And, the optical writing head
100
is constructed so as to switch with moving action the plural kinds of filters (R, G, B) located movably in the direction of sub-scanning.
Accordingly, the aforementioned conventional optical printer requires wide space for moving the optical print head
100
.
And, in case of the aforementioned conventional optical printer, the scanning should be performed repeatedly corresponding to the number of the filter (three filters R G B in the aforementioned

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