Apparatus for making contact prints

An apparatus for making contact prints, the apparatus including a frame having a transparent plate, and a pair of frame carriers for supporting the frame at opposite sides of the printing box such that the frame is placeable over the printing plate in an optically sealed manner, each of the frame carrier including a stop means for anchoring the frame carrier at a predetermined position alongside the printing box.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for making contact prints, 
and more particularly to an apparatus which makes prints by placing a 
sensitive sheet in contact with a negative and exposing the same to light 
through the negative. Hereinafter, the apparatus will be referred to as 
the "printing apparatus". 
2. Description of the Prior Art 
There are a variety of printing apparatus known in the art, among which are 
those disclosed in Japanese Patent Publication (examined) No. 61-38455 and 
Utility Model Publication (unexamined) No. 56-10624. The basic structure 
of the present invention is in common with these known apparatus, and to 
explain the background of the present invention, it will be described by 
reference to prior art FIG. 5 herein. 
The example in the illustration is a vacuum type device, which comprises a 
printing box 1, a printing plate 2 having a soft sheet, and a frame 4 
pivotally connected to the box 1 by hinges 3, the frame 4 including a 
transparent plate 5 such as glass. The printing plate 2 is provided with a 
packing 7 at its periphery, whereby when the frame 4 is placed over the 
printing plate 2, the optical seal therebetween is secured. The reference 
numeral 11 denotes a handle. 
In addition to the hinges 3, the frame 4 and the box 1 are connected to 
each other by gas springs 8, whereby the opening and closing of the frame 
4 is facilitated. When the frame 4 is placed over the printing plate 2, a 
confined space is formed therebetween. The air inside the confined space 
is removed by a vacuum pump (not shown) through bores 9. There is provided 
a source of light 10 above the frame 4. 
A sensitive sheet is placed on the printing plate 2, and a negative is 
overlaid on the sensitive sheet. The frame 4 is placed over the printing 
plate 2. Then the vacuum pump is driven to evaculate the air from the 
confined space between the frame 4 and the printing plate 2, thereby 
securing a tight contact between the sensitive sheet and the negative at 
vacuum. Then the source of light 10 is illuminated, thereby projecting the 
image in the film onto the sensitive sheet. 
A disadvantage of this type of printing apparatus is that the inner surface 
of the transparent plate 5 is liable to become stained with ink, an 
adhesive or dirt floating in air. A stain on the transparent plate 5 
causes a pinhole and spoils the formation of an image. Consequently, a 
constant care is required such as by wiping or applying a cleanser, to 
keep the inner surface of the transparent plate 5 clean. On the other 
hand, a stain on the outer surface of the transparent plate 5 does not so 
seriously affect the formation of an image as on the inner surface, 
because of the fact that light is diffused during passage through the 
transparent plate 5 (normally 5 mm thick). Any stain on the outer surface 
has only to be brushed. No troublesome taking-care is necessary. 
An elaborate maintenance procedure is required for keeping the inner 
surface of the transparent plate 5 clean. Particularly a large-scale 
apparatus will require a lot of labor; for example, when the transparent 
plate 5 is as large as 1.5 m.sup.2 in area, the lower portion of the 
transparent plate 5 is out of reach from the front side (indicated by 
arrow (A)) of the apparatus. As a result, the alternative way is to clean 
the transparent plate 5 from either side indicated by arrow (B). However, 
when the apparatus is crowded by other office furniture, access to the 
sides of the device is difficult if not impossible. 
OBJECTS AND SUMMARY OF THE INVENTION 
The present invention aims to provide a printing apparatus which solves the 
above problems in the known apparatus discussed above. Thus an object of 
the present invention is to provide a printing apparatus which makes it 
easy to place the the transparent plate within reach of an operator, 
thereby facilitating the constant taking-care of the transparent plate. 
This object is achieved by providing a printing apparatus having a printing 
box, a printing plate, and a frame having a transparent plate, the 
apparatus further comprising a pair of frame carriers for supporting the 
frame, the frame carriers being provided on opposite sides of the printing 
box such that the frame is placeable over the printing plate in an 
optically sealed manner, each of the frame carrier including a stop means 
for anchoring the frame carrier at a predetermined position alongside the 
printing box. 
Other objects and advantages of the present invention will become more 
apparent from the following detailed description, when taken in 
conjunction with the accompanying drawings which show, for the purpose of 
illustration only, one embodiment in accordance with the present invention 
.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1 and 2, the illustrated embodiment of the present 
invention is basically identical in structure to the known apparatus shown 
in FIG. 5. Throughout FIGS. 1 to 4 like reference numerals denote like 
compounds in FIG. 5. 
The embodiment of the present invention is different from the known 
apparatus of FIG. 5, in that the frame 4 is supported by frame carriers 
30, which are secured to the box 1. In the apparatus of FIG. 5, the frame 
4 is directly connected to the printing box 1 by means of the gas springs 
8. The frame carrier 30 includes a rail 22 and a slider 20 slidable on and 
along the rail 22. The frame 4 is supported freely of the box 1, unlike 
the embodiment of FIG. 5, in which the frame 4 is hinged thereto. The 
frame 4 has dowels 24 at the lower rim, and is supported on the frame 
carrier 30 by fitting the dowels 24 in receptive holes 24 of the sliders 
20. 
Referring to FIGS. 3 and 4, the frame carrier 30 will be described in 
greater detail. 
Each rail 22 is provided with anchorage apertures 32 and 34 spaced from 
each other, in which the respective slider 20 is anchored by means of a 
lock pin 42. The lock pin 42 has a knob 46 fixed thereto by a pin 44, and 
is insertable in the anchorage apertures 32 or 34 under the urge of a coil 
spring 48. The reference numeral 40 denotes a washer. The locking and 
unlocking is facilitated by lock aid members 40, each of which is located 
between the slider 20 and the knob 46. As best shown in FIG. 4, the lock 
aid member 40 is provided with convex sections 40b and a concave section 
40a therebetween. When the knob 46 fits in the concave section 40a, the 
lock pin 42 is inserted in the anchorage aperture 32 or 34 under the 
action of the coil spring 48, whereas when the knob 46 rides on the convex 
sections 40b, the lock pin 42 is released from the anchorage aperture 32 
or 34. FIG. 3 shows that the lock pin 42 is anchored in the aperture 32 or 
34; at this stage, the knob 46 fits in the concave section 40a. The knob 
46 is pulled in the direction of arrow (C) (FIG. 3), and is rotated in 
either of the clockwise or counter-clockwise direction until it rides on 
the convex sections 40b. By releasing the lock pins 42 from the apertures 
32 or 34, the sliders 20 are readied for sliding along the rails 22. If 
the operator wants to anchor the frame carriers 30 automatically to 
desired apertures 32 or 34, the sliders 20 are moved with the lock pins 42 
dragging on the rails 22. In this state the knobs 46 only slightly fit in 
the concave sections 40a of the respective lock aid members 40. When the 
sliders 20 reach the desired apertures 32 or 34, the lock pins 42 are 
caused to fit therein under the action of the coil springs 48. 
In this way the transparent plate 5 is readily moved to and from the front 
side of the apparatus. When the rear side of the transparent plate 5 is to 
be cleaned, the sliders 20 are released from anchorage at the apertures 
34, and the transparent plate 5 is pulled with the handle 11 so as to 
locate it within reach of the operator's hands. When the sliders 20 are 
anchored at the apertures 32, the transparent plate 5 is within reach, and 
is accessible for being cleaned. When the cleaning is finished, the 
transparent plate 5 is returned to its original position shown in FIG. 1. 
When the apparatus is very large, a pneumatic cylinder or any other power 
driving means may be employed instead of the gas springs 8.