System for loading sheet materials on a rotary drum

A system for loading sheet materials on a rotary drum, having carrier for carrying sheet materials to the drum, a mechanism for catching the leading end of the sheet materials on the drum, and a presser member for pressing the sheet materials to said drum rotating, so as to wind said sheet materials around said drum, wherein said system involves a dampening arrangement for dampening the space between sheet materials and the drum surface, which is mirror finished, so as to contact said sheet materials with said peripheral surface of said drum.

FIELD OF THE INVENTION 
The present invention relates to a system for loading sheet materials on a 
rotary drum, especially to such system having means for holding the 
leading end of the sheet materials on the drum, and means for pressing the 
sheet materials to said drum rotating, so as to wind said sheet materials 
around said drum. 
BACKGROUND OF THE INVENTION 
Such systems for loading sheet materials on a rotary drum are disclosed by 
Japanese Patent Publication No. 56-24270, or Japanese Open Patent 
Publication No. 59-171676, for example. 
In the former publication, the system involves a suction opening which 
suckes back surface of the sheet materials at the leading end. And in the 
latter publication, the system involves a clamp mechanism (gripper) for 
clamping the leading end of the sheet materials. 
In such system, it is desirable that the sheet materials perfectly contact 
with the peripheral surface of the drum. But, according to these prior 
arts, it is found that there are partial spaces between the sheet 
materials and the peripheral surface of the drum sometimes. 
Therefore, in case that these prior arts are applied to an 
electrophotocopying machine of CPC type, the image is out of focus at the 
risen part from the drum surface, making the sharpness lower, and liquid 
developer invades into the partial spaces between the sheet materials and 
the peripheral surface of the drum, blotting the back of the sheet 
materials. 
And in case that these prior arts are applied to a rotary press for light 
printings, which uses a master paper as sheet forms, inks enter into the 
spaces between the master paper and the drum and decreases the value of 
goods when they are adhered to the margine part of the paper. Moreover, 
the master paper is partially spaced from the drum by the centrifugal 
force during high speed printing. 
The suction opening is desirable for making no turning-in at the leading 
end of the sheet materials. But, it may allow of the slip or creases of 
sheet materials, which may be fatal defects for color copying obtained 
through several different color developments on one developing paper by a 
color electrophotocopying machine or the like, especially, when the spaces 
mentioned above is broken out. 
When hard or thick sheet materials are used, the sheet materials is tending 
to rise from the drum surface by the reaction of cylindrical bending along 
the drum, in comparison with the different case in which the sheet 
materials are laid on a flat form. Therefore, there is limitation of the 
sheet materials in thickness or hardness thereof. 
Therefore, the object of the present invention is to propose a system for 
loading sheet materials on a drum, which disadvantages abovementioned are 
resolved. 
DISCLOSURE OF THE INVENTION 
To achieve the object abovementioned, a system for loading sheet materials 
on a drum, described in the opening paragraph, according to the present 
invention, essentially involves a dampening arrangement for dampening of 
the sheet materials back surfaces and/or drum surface at least before 
holding of leading end of the sheet materials, and the drum having a 
mirror finished peripheral surface, so as to tightly contact the sheet 
materials on the peripheral surface of the drum. 
At least one of the sheet materials or drum is dampened by the dampening 
arrangement before the leading end of the sheet materials is caught by 
means for catching, then the leading end of the sheet materials is caught 
and loaded by winding it around the drum. The space between sheet 
materials, which is pressed to the drum surface by the presser member, and 
drum surface is dampened and contacted tightly each other with no space 
therebetween. Thus, the partial space between them, slip and creasing of 
the sheet materials, both are brought out by the partial space 
therebetween are prevented.

BEST MODE FOR PRACTICING THE INVENTION 
A color electrophotocopying machine according to the present invention is 
explained hereinafter. 
FIG. 2 is a schematic side view of the color electrophotocopying machine 
according to the present invention. In FIG. 2, drum 1 is provided for 
loading a sheet of light sensitive paper 2, and a developing machine 3 
which developes electrostatic latent image formed on the light sensitive 
paper 2, and which is arranged to feed different color developers orderly 
as described later. The machine is provided with a feeder 4 which feeds 
light sensitive paper 2 to the drum 1, a charging device 5 which charges 
static electricity to the light sensitive paper 2, an optical instrument 6 
for producing an electrostatic latent image, a developing machine 3, an 
air knife 7, a remover 8 for removing sheet materials from the drum 1, 
drum cleaner 9, a discharger 10, and so on. They are disposed against the 
drum 1 and in order. 
The optical instrument 6 is provided with a holding frame 11 for holding an 
original 12, a light source 13, one or a set of lenz 14, color filters 15, 
and a mirror 16, so as to form an electrostatic latent image by projecting 
optical slit images of the original, which optical slit images are 
obtained by moving the holding frame 11 holding the original 12, in the 
direction designated by an arrow A. 
The developing part 30 of the wet developing machine 3 has a cyanic 
developing unit 3C, a magenta developing unit 3M, yellow developing unit 
3Y, and optical gray developing unit (not shown), for developing separated 
color electrostatic latent images. One separated color electrostatic 
latent image is formed and developed on a developing paper 12 
monochromatically. Then, the formings of different separated color 
electrostatic latent images and developements of them on the same paper 2 
are carried in the same way orderly by color. 
These developing units 3C, 3M, 3Y are movable up and down (in the direction 
of the arrow D) and carried by the carrier 31 which moves right and left 
(in the direction of the arrow C). The carrier 31 is moved and positioned 
by a driving device 34 having a motor 32, a chain 33 and so on, and any 
one of developing unit, which is desired to work, approaches to the 
surface of developing paper 2 by means for lifting the developing unit 39, 
which involves a motor 36, a lifting crank mechanism 37, a lifting table 
38 and so on, in order to feed developer 41 from a developer tank 40 to 
the surface of light sensitive paper 2 by a feeding pump 42. 
FIG. 1 is a side view of the essential part of the present invention, 
wherein a casset reel 43 for rolled light sensitive paper 2 is housed in a 
magazine 44 having a pair of rollers 45 for taking out the leading end of 
the light sensitive paper 2 from the magazine 44 in order to insert it to 
a pair of feeding roller 46. A paper carrier 4 involves two pairs of 
rollers 4a, 4b which carry the light sensitive paper 2 fed from the 
feeding rollers 46. The speed of the paper 2 carried by this paper carrier 
4 is controlled by an usual timing controller (not shown) which delivers 
pulses for controlling the work timing the connected electric parts or 
circuits by numbers of pulses, so as to be synchronized with the rotating 
position of the suction port 53 of the drum 1 rotating in the direction of 
an arrow B. A cutter 47 is disposed between feeding rollers 46 and the 
paper carrier 4. The developing paper 2 is pressed to the drum 1 by the 
presser member 52. 
These constitutions of the inventions described hereinbefore are known 
constitutions, and the essential and particular constitutions, which 
feature the present invention, of the present invention will be described 
hereinafter. 
A dampening arrangement 51 is positioned under the carrier rollers 4a, 4b 
for dampening the light sensitive paper 2. This dampening arrangement 51 
involves a dampening roller 48 consisted of the lower one of a pair of 
carrier roller 4a, so as to feed dampening agents 49 (for example, solvent 
of the developer 41) from a tray 50 to the back surface of the light 
sensitive paper 2. A drum dampening arrangement 62 also exists for the 
surface of the rotary drum 1. 
Of course, the constitution of the dampening arrangement 51 is not limited 
in that described above. For example, the independent dampening roller (of 
porus elastomer such as sponges), or showering system, spraying system, 
brush and so on may be altered with the carrier roller 4a(48). 
The dampening arrangement may be adapted to dampen both the surface of the 
drum 1 and the light sensitive paper 2, or only the surface of the drum 1. 
Any way, it is necessary that the space between the drum 1 and the paper 2 
is soaked with the dampening agents. The preferable composition of the 
dampening agents may be selected taking acount of the type of machine to 
be applied. 
As dampening agent may be used in case of electrophotographic printing in 
conjunction with the present invention, there may be used various organic 
liquid, preferably, solvent of liquid developer for electrophotography 
such as electrically insulating carrier liquid of the liquid developer. If 
there was no particular limitation, water may be used as the dampening 
agent. 
The dampening agents 49 is supplied by the supply system 58 shown by 
imaginary lines, and placed at one side of the drum 1. 
The surface of the drum 1 is mirror finished and the roughness which is 
obtained by electroplating may suffice required roughness generally. But, 
the character of the dampening agents influences the requirement in the 
roughness, so that it may be considerably rough in some case, or 
considerably fine or smooth in other case. 
A suction opening 57 for catching the leading end 2a of the light sensitive 
paper 2 is assembled in the drum 1, and involves a suction port 53 formed 
on the drum surface parallel with the axis of the drum 1. The suction port 
53 is communicated with a vacuum pump 56 located outside of the drum 1, 
via duct 54 formed in the drum axle 19, and a pressure sensor 55 disposed 
outside of the drum 1. 
The suction port 53 may involve a numerous numbers of suction bores aligned 
in the direction of the drum axis, or one or more openings like slits. 
The pressure sensor 55 is provided for detecting the miss in catching of 
the light sensitive paper 2 by sensing the drop of vacuum pressure under 
the predetermined value, and for breaking out of emergency alarm, and/or 
work of the copying machine, so as to prevent jam of the light sensitive 
paper when the miss is found out thereby. 
The invention is explained along its application to a color 
electrophotocopying machine herein above, but the field, to which the 
present invention can be applied, is not limited within there, but in the 
field of monochromatic electrophotocopying machine, rotary press for a 
light printings, and so on. 
In case of the rotary press according to the invention, it is possible to 
prevent the invasion of the oil inks into the space between the master 
paper, which is the form, and presser drum by repelling it with water used 
as the dampening agents 49. 
Of course, the means for holding the leading end of the developing paper, 
being comprised of a suction opening may be altered with a clamping 
mechanism, or known gipper, for example. 
As said photosensitive sheet may be used in conjunction with the present 
invention comprise a backing of relatively electrically conductive 
material sheet such as paper or plastic film, coated with an 
electroconductive materials or of metal plate having a coating of 
electrophotoconductive material layer such as titanium dioxide, zinc oxide 
and the like dispersed in a resinous binder on one surface thereof to 
provide the photoconductive surface, especially, in case that titanium 
dioxide containing photosensitive sheet is employed in the present 
invention, thereby resulting multi-color print image having high contrast 
with good continuous gradation of the image such as that pictorial tone 
resembling the appearance obtainable in silver halide photography. 
EFFECTS OF THE INVENTION 
According to the present invention, the sheet materials is loaded with 
dampening of the space between sheet materials and drum surface, so that 
the following outstanding advantages are brought out. 
A. The back of the sheet materials is tightly contacted with the drum 
surface, so that the slip and creasing of the sheet materials caused by 
the rising of sheet materials from the drum surface is prevented. 
B. And the focus of the copying or reproduction is kept correct, in case of 
electrophotocopying machine according to the present invention. 
C. The color discrepancy caused by the slip or creasing of the sheet 
materials is eliminated in case of color electrophotocopying machine 
according to the present invention. 
D. The disadvantage of the usual rotary press for light printing, that the 
value of goods is spoiled by the inks invaded in the space between the 
master paper and the drum, is eliminated in case of rotary press according 
to the present invention. 
E. The thicker or harder sheet materials are able to load on a drum without 
rising thereof from the drum surface, so that the sorts of the sheet 
materials to be loaded on a drum is increased.