Electrophotographic copying apparatus equipped with copying coverage indication device

An electrophotographic copying apparatus is equipped with an indication device for the maximum area to be covered by copying, i.e. the area available for copying or copying coverage. The copying coverage indication device which includes a micro-computer is arranged to indicate the area to be covered by copying according to the sizes of copy paper sheets and copying magnifications for preventing use of copy paper sheets of unnecessarily large or small sizes, and is capable of warning an operator of the necessity for exchanging sizes of copy paper sheets.

BACKGROUND OF THE INVENTION 
The present invention relates to an electrophotographic copying apparatus 
and more particularly, to an electrophotographic copying apparatus 
equipped with a copying coverage indication device which indicates the 
maximum area to be covered by copying, i.e. the area vailable for copying 
or copying coverage, on an original platform of the electrophotographic 
copying apparatus capable of selectively using copy paper sheets of a 
plurality of different sizes and provided with a variable magnification 
function. 
Generally, in electrophotographic copying apparatuses, it is so arranged 
that an original to be copied placed on a transparent platform is 
illuminated by a light source or exposure lamp from the under surface of 
the original so as to project the light-wise image reflected from the 
original onto a photosensitive member or photoreceptor through an optical 
system including a lens assembly, etc., and in the case of copying at a 
magnification of 1:1 or equal size magnification, since the area to be 
covered by copying with respect to the size of the selected copy paper 
sheets is the size of the copy paper sheet itself, an operator of the 
copying apparatus has only to align one edge of the original with a 
reference side or datum line given on the original platform to set the 
original within a range indicated by a size scale or the like provided 
along the reference side. 
However, in an electrophotographic copying apparatus capable of selectively 
using copy paper sheets of a plurality of different sizes and also 
provided with a variable magnification function, the size of the copy 
paper sheet does not necessarily coincide with the area to be covered by 
the copying operation or the area available for copying, and it has been 
quite troublesome for the operator to select a copy paper sheet of optimum 
size based on the size of the original and the magnification for the 
copying or to judge the size of the original which can be used according 
to the selected copy paper sheet size and the copying magnification, thus 
frequently giving rise to such inconveniences as employing copy paper 
sheets of unnecessarily large size, or undesirably using copy paper sheets 
too small for the size of the copied images. 
In the conventional copying apparatuses of this kind, determination of the 
copy paper sheet size or the area to be covered by copying has almost been 
left to the operator, and although some of the conventional copying 
apparatuses are arranged merely to indicate the maximum area to be covered 
by copying for each copying magnification by scales and the like, there 
has been no arrangement for indicating the area available for copying in 
relation with the copy paper sheet size, thus still imposing troubles as 
described above on the operators. 
Meanwhile, no particular attention has yet been drawn to automatically 
effecting determinations as described above, since in such an automated 
arrangement, if many kinds of copy sheets are involved, with a variety of 
copying magnifications, extremely expensive and complicated mechanisms are 
inevitably required, and thus, the inconveniences on the part of the 
operators as described earlier have not at all been eliminated at the 
present stage. 
SUMMARY OF THE INVENTION 
Accordingly, an essential object of the present invention is to provide an 
electrophotographic copying apparatus equipped with a copying coverage 
indication device which is arranged to indicate the area to be covered by 
the copying operation, i.e., the area available for copying or copying 
coverage according to the size of copy paper sheets and copying 
magnifications for preventing use of copy paper sheets of unnecessarily 
large or small sizes. 
Another important object of the present invention is to provide an 
electrophotographic copying apparatus equipped with a copying coverage 
indication device of the above described type which is capable of warning 
the operator of necessity for exchanging sizes of the copy paper sheets, 
if unsuitable magnification is selected with respect to copy paper sheet 
sizes. 
A further object of the present invention is to provide an 
electrophotographic copying apparatus equipped with a copying coverage 
indication device of the above described type in which the indications as 
described in the foregoing are effected through utilization of memory and 
judging functions of a micro-computer employed for control of operations 
of the copying apparatus so that the foregoing objects of the invention 
are achieved without increased size and complication of the copying 
apparatus, even in an electrophotographic copying apparatus capable of 
selecting a variety of copy paper sheet sizes and copying magnifications. 
A still further object of the present invention is to provide an 
electrophotographic copying apparatus equipped with a copying coverage 
indication device of the above described type which is simple in 
construction and accurate in functioning, and can be manufactured at low 
cost. 
In accomplishing these and other objects, according to one preferred 
embodiment of the present invention, the electrophotographic copying 
apparatus which is provided with an original platform of transparent plate 
material, a scanning optical system which scans an original placed on the 
original platform while illuminating the original from the under surface 
of the original platform for directing a light-wise image of the original 
onto a photoreceptor, means for varying the scanning speed of the scanning 
optical system corresponding to various copying magnifications, and means 
for mounting copy paper which is capable of loading thereon a plurality of 
sizes of copy paper, further includes means for selecting the copying 
magnifications, means for detecting the magnifications and which emits 
signals respectively corresponding to the copying magnifications selected 
by the copying magnification selecting means, means for detecting sizes 
which detects the size of the copy paper loaded on the copy paper mounting 
means for emitting signals corresponding to the detected size, means for 
judging the area available for the copying operation and which receives 
signals from the magnification detecting means and said size detecting 
means for judging the area available for copying on a plane including the 
original platform, means for indicating the area available for the copying 
operation and which is selectively actuated corresponding to output of the 
available copying area judging means, and means for detecting when the 
area available for copying judged by the available copying area judging 
means has exceeded the actual area available for copying for the 
electrophotographic copying apparatus. 
By the arrangement according to the present invention as described above, 
since the area to be covered by copying, i.e. the area available for 
copying or copying coverage, is clearly indicated according to the 
combinations of the copy paper sizes and copying magnifications, 
inconveniences inherent in the conventional arrangements such as use of a 
copy paper sheet unnecessarily large with respect to the original or 
employment of a copy paper sheet too small for the desired image are 
advantageously prevented. Moreover, owing to the arrangement to give 
warnings for copy paper size exchange if a copy paper sheet of unsuitable 
size is selected, wasteful use of the copy paper sheets are also 
eliminated.

Before the description of the present invention proceeds, it is to be noted 
that like parts are designated by like reference numerals throughout the 
several views of the accompanying drawings. 
DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, there is shown in FIG. 1 an 
electrophotographic copying apparatus to which the copying coverage 
indication device directly related to the present invention may be 
applied. 
In FIG. 1, the copying apparatus G generally includes an apparatus housing 
Ga of rectangular box-like configuration defined by walls, and a 
photosensitive member or photoreceptor drum 1 of known construction having 
a photoconductive photoreceptor surface 1a provided on the outer periphery 
thereof and rotatably disposed at approximately the central portion of the 
housing Ga for rotation in the direction of the arrow to cause the 
photoreceptor surface 1a to sequentially pass various processing stations 
disposed therearound for image formation, such as a charging station with 
a corona charger 2, an exposure station E, a developing station having a 
developing unit 3, a transfer station having a transfer charger 4, a 
charge erasing station provided with an AC discharger 5, a copy paper 
sheet separating station with a separating claw 6, a cleaning station 
having a cleaning unit 7, etc. 
At the upper portion of the housing Ga, there is provided a platform 10 of 
light transmitting transparent material for placing an original O to be 
copied thereon, while below and adjacent to the platform 10, an optical 
system F including an exposure lamp l, first, second, third and fourth 
reflecting mirrors m.sub.1, m.sub.2, m.sub.3 and m.sub.4, lens assembly L, 
etc. is provided for directing a light-wise image of the original O onto 
the photoreceptor surface 1a at the exposure station E in a manner as 
described hereinbelow. 
The exposure lamp l and the suitably inclined first reflecting mirror 
m.sub.1 are fixedly mounted on a fixing member (not shown) which is 
secured to or integrally formed with a slider member 9a slidably mounted 
on a rail member 8 so as to be moved leftward by driving means (not shown) 
from the position shown in FIG. 1 in parallel relation with the platform 
10 at a speed of V/M, wherein V represents the copy paper sheet 
transportation speed (speed of rotation of the photoreceptor drum 1) and M 
denotes the copying magnification. The second reflecting mirror m.sub.2 is 
secured to another slider member 9b also slidably mounted on the rail 8 
for being moved leftward in FIG. 1 by driving means (not shown) in 
synchronization with the movement of the exposure lamp l, etc. at a speed 
of V/2M, while the reflecting mirrors m.sub.3 and m.sub.4 are fixedly 
mounted to frames of the housing Ga and respectively inclined at 
predetermined angles to direct the light-wise image of the original toward 
the exposure station E onto the photoreceptor surface 1a. 
The copying magnification is, for example, approximately 0.816 in the 
reduced scale or contraction copying through change-over of A row and B 
row of the copy paper sheet sizes, and approximately 0.707 in the case of 
reduced scale copying at an area ratio of 1/2. Meanwhile, the changeover 
of the speeds as described in the foregoing may be achieved by means of 
changing over of clutch means (not shown) through a suitable copying 
magnification selecting operation, variation of gear ratios, etc. 
It is to be noted here that the expressions such as A row and B row 
employed throughout the present specification for denoting paper sizes are 
based on Japanese Industrial Standards (JIS), in which the paper sizes are 
represented both for the A row and B row in the order from larger size to 
smaller size in such a manner as A0 (A zero), A1, A2, . . . , A12, and B0 
(B zero), B1, B2, . . . , B12, etc. Specific paper sizes for respective 
symbols are given in Table 1 below. 
TABLE 1 
______________________________________ 
Finished dimensions by JIS Standards 
A row No. 
Unit (mm) B row No. Unit (mm) 
______________________________________ 
0 841 .times. 
1 189 
0 1 030 .times. 
1 456 
1 594 .times. 
841 1 728 .times. 
1 030 
2 420 .times. 
594 2 515 .times. 
728 
3 297 .times. 
420 3 364 .times. 
515 
4 210 .times. 
297 4 257 .times. 
364 
5 148 .times. 
210 5 182 .times. 
257 
6 105 .times. 
148 6 128 .times. 
182 
7 74 .times. 
105 7 91 .times. 
128 
8 52 .times. 
74 8 64 .times. 
91 
9 37 .times. 
52 9 45 .times. 
64 
10 26 .times. 
37 10 32 .times. 
45 
11 18 .times. 
26 11 22 .times. 
32 
12 13 .times. 
18 12 16 .times. 
22 
______________________________________ 
The light-wise image of the original O scanned by the optical system F is 
projected onto the photoreceptor surface 1a of the rotating photoreceptor 
drum 1 at the exposure station E in the manner as described earlier to 
form thereon an electrostatic latent image, which is then developed into a 
visible toner image by the developing device 3 for being subsequently 
transferred by the transfer charger 4 onto a copy paper sheet P 
transported in synchronization with the proceeding of the development, and 
thereafter, the copy paper sheet P bearing the visible toner image thus 
transferred thereon is separated from the photoreceptor surface 1a by 
means of the AC discharger 5, separating claw 6, etc. so as to be further 
transported, through a transportation belt 11 movably supported by a 
plurality of rollers in a position subsequent to the transfer charger 4, 
to a fixing device 12 including a heat roller h for fixing the visible 
toner image onto the copy paper sheet P by heating, and then, the copy 
paper sheet bearing the copied image is discharged onto a tray 13 for 
completion of one copying cycle. 
For making it possible to simultaneously stock, for example, two different 
sizes of copy paper sheets P, the copying apparatus G is provided, at the 
lower left portion of the housing Ga, with two copy paper sheet containers 
or cassettes C.sub.1 and C.sub.2 in which stacks of the copy paper sheets 
P of different sizes are respectively accommodated, and by selectively 
operating copy paper sheet feeding rollers R.sub.1 and R.sub.2 provided in 
positions corresponding to the cassettes C.sub.1 and C.sub.2 by suitable 
means (not shown), either one of the copy paper sheets P contained in the 
cassette C.sub.1 or C.sub.2 is fed one by one from the top of the stack of 
the copy paper sheets P toward the transfer station through corresponding 
guide plates and feeding rollers. 
Referring to FIG. 2, the copying coverage indication device D for 
indicating the area to be covered by the copying operation, i.e. available 
copying area or copying coverage, directly related to the present 
invention and incorporated in the electrophotographic copying apparatus G 
of FIG. 1 will be explained hereinbelow. 
In FIG. 2, the copying coverage indication device D generally includes 
indicator sections 102 and 103 respectively provided adjacent to 
neighboring two sides 10a and 10b of the original platform 10 and having 
indicator lamps, for example, light emitting diodes (LED) arranged in 
positions corresponding to the sizes of the copy paper sheet which may be 
employed for the copying operation so as to indicate the area to be 
covered by the intended copying operation by illumination of the light 
emitting diodes LED. For the above purpose, for example, the positions of 
the light emitting diodes LED arranged on the indicating section 103 
adjacent to the side 10b of the original platform 10 are designated as A, 
B, C, D and E from the side 10c opposite to the datum side 10a toward side 
10a for respectively representing lengths in the longitudinal direction 
from the datum side 10a for A3 size by the LED at A, B4 size by B, A4 size 
by C, B5 size by D and so on, while in the indicating section 102, light 
emitting diodes are symmetrically arranged in pairs with respect to the 
central portion of the datum side 10a in positions A', B', C', D' and E' 
from the side 10b and side 10d opposite thereto, toward the central 
portion of the datum side 10a as shown for indicating the positions in the 
width-wise direction of the copy paper sheets in correspondence with the 
longitudinal lengths A, B, C, D and E mentioned above in the indicator 
section 103. By the above arrangement, the area to be covered by the 
particular copying operation, i.e. the available copying area or copying 
coverage, is clearly indicated through combinations of illuminated light 
emitting diodes LED at the respective positions mentioned above. 
Reference is had to FIGS. 3 and 4 showing an electrical circuit arrangement 
for causing the light emitting diodes LED to be selectively illuminated 
according to the size of a selected copy paper sheet and copying 
magnification so as to indicate the copying coverage. It is to be noted 
that in the embodiment of FIGS. 3 and 4, the control as mentioned above is 
arranged to be effected through utilization of memory and decision 
functions of a micro-computer MC, for example, a .mu.COM 43 (name used in 
the trade and manufactured by Nippon Electric Co., Ltd.) which is used for 
sequence control, etc. of the function of the copying apparatus G. 
The micro-computer MC of FIG. 3 includes a central processing unit (CPU) 
201 in which an arithmetic and logic unit (ALU) 202, an accumulator (ACC) 
203, an instruction decoder (DEC) 204, a program counter (PC) 205, a stack 
pointer (SP) 206, a timer (T) 207 and the like are integrated, and one or 
a plurality of large scale integrated circuits LSI having random access 
memory (RAM) 208 and read only memory (ROM) 209, etc., based on 
fundamental construction of a semiconductor memory cell for receiving 
signals from external circuits and also for emitting control signals 
therefrom through an input/output interface I/O 210 in a known manner. 
Since the functions of the micro-computer MC as described above for the 
sequence control of the operations for the copying apparatus G of FIG. 1 
are not directly related to the present invention, the detail description 
thereof provided herein is abbreviated. 
According to the present invention, detection signals from copy paper sheet 
size detection means and copying magnification detection means to be 
described later are applied to the micro-computer MC through an input port 
of the input/output interface I/O 210, and according to the program 
memorized in ROM 209, control signals are output from output ports of the 
interface I/O 210 into an indication circuit as shown in FIG. 4 for 
illuminating corresponding light emitting diodes LED. 
In FIG. 4, eight outputs in total from the output ports PE.phi., PE1, PE2 
and PE3, and PF.phi., PF1, PF2 and PF3 coupled to corresponding switching 
circuits S.sub.1, S.sub.2, S.sub.3, S.sub.4, S.sub.5, S.sub.6, S.sub.7 and 
S.sub.8 as shown are used for the illumination control of the above 
described emitting diodes LED. The outputs are first applied to the 
switching circuits S.sub.1 to S.sub.8 for turning ON or rendering 
conductive only those of the switching circuits S.sub.1 to S.sub.8 which 
actually receive the output signals. The switching circuit S.sub.1 is 
connected to the base of a transistor TR.sub.1 through a resistor R.sub.1, 
while light emitting diodes LED-A, LED-B, LED-C and LED-D are coupled, 
through corresponding resistors R.sub.2, R.sub.3, R.sub.4 and R.sub.5, to 
the collector of the transistor TR.sub.1, with light emitting diodes 
LED-A, LED-B, LED-C and LED-D being further coupled to the switching 
circuits S.sub.8, S.sub.7, S.sub.6 and S.sub.5 respectively. The switching 
circuit S.sub.2 is connected, through a resistor R.sub.6, to the base of a 
transistor TR.sub.2 whose collector is connected to the light emitting 
diodes LED-A', LED-B', LED-C' and LED-D' each in pair, which are further 
coupled to the switching circuits S.sub.8, S.sub.7, S.sub.6 and S.sub.5 
respectively. Meanwhile, the switching circuit S.sub.3 is connected 
through a resistor R.sub.15, to the base of a transistor TR.sub.3 whose 
collector is coupled through a resistor R.sub.16 to the light emitting 
diode LED-E which is further connected to the switching circuit S.sub.8. 
The switching circuit S.sub.4 is connected through a resistor R.sub.17 to 
the base of a transistor TR.sub.4 whose collector is coupled through a 
resistor R.sub.18, to the light emitting diode LED-E' which is further 
connected to the switching circuit S.sub.8. 
Referring also to a flow-chart of FIG. 5, the function and control of the 
circuit as described in the foregoing will be subsequently explained with 
reference to a case where copy paper sheets of A4 size are accommodated 
sidewise or laterally in the copy paper sheet cassette. 
Upon application of power supply to the copying apparatus G of FIG. 1, a 
power source (not shown) for the micro-computer MC as described in the 
foregoing is simultaneously turned ON for causing the micro-computer MC to 
start functioning. In the first place, at a step 1 in FIG. 5, the 
presence of copy paper sheets in the cassette is detected by copy paper 
sheet size detection means, and if the cassette is not fully loaded or is 
empty of copy paper sheets, a paper empty indication at a step 2 is 
given, while on the contrary, if the cassette is fully loaded, a 
subsequent size judging step 3 is entered, whereat a signal decided for 
each size through the interface input ports mentioned earlier is stored in 
the random access memory RAM 208 based on detecting signal from size 
detection means to be described later. 
Subsequently, at a next step 4 , the copying magnification is detected by 
the position of the lens assembly L (FIG. 1) which moves following the 
selection of the copying magnifications, so as to be also stored in the 
random access memory RAM 208 and memorized in the read only memory ROM 
209. The content of the memory temporarily stored in the accumulator ACC 
203 according to the program is compared with the above content stored in 
the random access memory RAM 208 for initiating the subsequent function. 
By way of example, on the assumption that the copying apparatus as 
described above has three kinds of copying magnifications, i.e. equal size 
magnification, 0.816 power reduced scale magnification (contraction A) and 
0.707 power reduced scale magnification (contraction B), judgement is made 
as to whether the lens assembly L is located in the contraction A (step 5 
) or in the contraction B (step 6 ), and if the lens assembly L is not 
present either in the position for the contraction A or in the position 
for the contraction B, a program at step 7 for the equal size 
magnification is executed. 
If the copy paper sheets detected are of A4 size directed sidewise, with 
the lens assembly L being at the position for the contraction A, the 
program at step 5 produces 1 at the output ports PE1 and PF3 of the 
interface I/O 210, i.e. generates outputs from such output ports. 
Accordingly, the switching circuits S.sub.2 and S.sub.8 are turned ON to 
illuminate the light emitting diode LED-A'. Similarly, outputs are also 
produced from the output ports PE.phi. and PF.phi. for turning ON the 
switching circuits S.sub.1 and S.sub.5, with consequent illumination of 
the light emitting diode LED-D. 
The above indications show that when copy paper sheets of A4 size directed 
sidewise are employed, an original accommodated in the area indicated by 
the light emitting diodes LED-A' and LED-D may be copied, but since the 
copy paper sheets of A4 size are directed sidewise, the actual area to be 
covered by the copying ought to be larger than that indicated by the light 
emitting diode LED-A'. Accordingly, the copy paper size thus indicated is 
improper for the reduced scale copying and therefore, a size exchange 
indication is turned ON at a step 8 , together with the illumination of 
the light emitting diodes LED-A' and LED-D as described above. The size 
exchange indication may be suitably made in the indicating section 103, 
for example, by illumination of a lamp CHL (FIG. 2) or the like. 
In a manner similar to that described above, when the contraction B is 
selected, with the step 6 being executed, the light emitting diodes 
LED-A' and LED-C are lit, and the size exchange indication is 
simultaneously turned ON. In the case of the equal size magnification at a 
step 7 , since it is not necessary to indicate the size exchange, only 
the lateral positioning of the A4 size copy paper sheets is indicated by 
the light emitting diodes LED-A' and LED-E. Meanwhile, before the 
judgement of the copying magnification, a detection is made as to whether 
a paper size indication switch (not shown) is turned ON or not at a step 
9 . The paper size indication switch is arranged to be depressed by an 
operator for indication of the actual size of the copy paper sheet ready 
for use at the time on the indication device D, and upon depression 
thereof, the program at the step 7 for the equal size magnification is 
directly executed without entering the copying magnification judging step, 
and the copy paper sheet size detected is indicated irrespective of the 
copying magnifications. 
In the flow-chart of FIG. 5 illustrating one example wherein the copy paper 
sheet of A4 size is loaded sidewise or laterally in the copying apparatus, 
the state of illumination of the light emitting diodes according to the 
combinations of the copy paper sheet sizes and copying magnifications is 
shown in Table 2 below. 
TABLE 2 
__________________________________________________________________________ 
1 2 3 4 5 6 7 
.phi..phi..phi.1 .phi..phi.1.phi. 
.phi..phi.11 
.phi.1.phi..phi. 
.phi.1.phi.1 
.phi.11.phi. 
.phi.111 
__________________________________________________________________________ 
A4 A4 B5 B5 
size A3 length- 
side- OP B4 length- 
side- 
wise wise wise wise 
AA' CC' EA' BB' DD' EB' 
.times. 1.0 
420 .times. 297 
297 .times. 210 
210 .times. 297 
OP 364 .times. 257 
257 .times. 182 
182 .times. 257 
AA' BB' DA' AA' CC' EA' 
.times. 0.816 
514 .times. 364 
364 .times. 257 
257 .times. 364 
OP 446 .times. 315 
315 .times. 223 
223 .times. 315 
AA' AA' CA' AA' BB' DA' 
.times. 0.707 
594 .times. 420 
420 .times. 297 
297 .times. 420 
OP 514 .times. 364 
364 .times. 257 
257 .times. 364 
__________________________________________________________________________ 
When it is so arranged that the copy paper sheet sizes of A3, A4 directed 
lengthwise, A4 directed sidewise, B4, B5 directed lengthwise and B5 
directed sidewise are employed for copying, these copy paper sheet sizes 
are respectively converted into codes .phi..phi..phi.1, .phi..phi.1.phi., 
.phi..phi.11, .phi.1.phi..phi., .phi.1.phi.1, .phi.11.phi. and .phi.111 as 
shown in Table 2 upon detection by the size detection means so as to be 
input to the random access memory RAM 208. It is to be noted that the code 
4 .phi.1.phi..phi. is for an optional purpose. In Table 2, the light 
emitting diodes LED to be illuminated according to the respective copy 
paper sheet sizes and copying magnifications are merely represented by the 
alphabetical symbols A to D and A' to D', while those for which the size 
exchange indication is turned ON are surrounded by circles. The figures 
given below the alphabetical symbols denote the calculated values in 
milli-meter (mm) for the areas that can actually be utilized for the 
copying operations. In the above case, since the reduction of 0.816 power 
is employed for contraction from the A row to B row in the illustrated 
embodiment, numerical errors to a certain extent are involved during 
change-over from the B row to A row. 
Although detailed description of individual functions of the circuit of 
FIG. 4 other than those illustrated in the flow-chart of FIG. 5 are 
abbreviated here for brevity, it is to be noted the arrangement is such 
that the emitter voltage (+12 V) of the transistors TR.sub.1 to TR.sub.4 
is applied to the light emitting diodes LED via the switching circuits 
S.sub.1 to S.sub.4 so as to determine the light emitting diodes LED to be 
illuminated by forming current paths from the voltage source through 
turning ON and OFF of the switching circuits S.sub.5 to S.sub.8. It should 
also be noted here that when the size exchange indication is effected as 
described in the foregoing, the circuit may be arranged to control the 
copying operation to be suspended, but the arrangement may be so made as 
to permit a copying operation itself by merely effecting the size exchange 
indication, with subsequent treatments left to the operator. 
Hereinbelow, the copy paper sheet size detection means and copying 
magnification detection means which apply inputs to the judging process 
mentioned above will be described with reference to FIG. 6. 
In the copy paper size detection means for identification of the copy paper 
sizes, for example, the copy paper sheet cassettes C.sub.1 and C.sub.2 
exclusive for corresponding copy paper sheet sizes are employed, while an 
actuator member 50 having a plurality of projections, for example, four 
projections 50a, 50b, 50c and 50d is provided on each of the cassettes 
C.sub.1 and C.sub.2 so as to extend outwardly from one side wall Cw 
thereof as shown in FIG. 6, and during loading of the cassettes C.sub.1 
and C.sub.2 onto the copying apparatus, the projections 50a to 50d are 
adapted to selectively actuate corresponding microswitches SW.sub.1, 
SW.sub.2, SW.sub.3 and SW.sub.4 provided on the side of the apparatus 
housing Ga (FIG. 1) for the sizing judgement. Therefore, for example, when 
the four projections 50a to 50d are provided as shown in FIG. 6, since the 
microswitches SW.sub.1 to SW.sub.4 are all turned ON, the judging codes 
are 1111, and by converting into signals of .phi. and 1 according to the 
presence of the projections 50, judgements corresponding to the sizes may 
be effected as shown in Table 2. 
It is to be noted that in Table 2, since the number of size judgements is 
six, the number of the projections 50 may be three, but for general use of 
the micro-computer MC, a four bit arrangement is shown in the illustrated 
embodiment, in which sixteen judgements are made possible including the 
code .phi..phi..phi..phi. in the absence of copy paper sheets and the code 
.phi.1.phi..phi. for the optional purpose. 
It should also be noted that, for the size detection means according to 
each of the copy paper sheet cassettes, various modifications, for 
example, means for converting optically detectable markings printed on the 
cassettes in white, black, etc. into electrical signals by a photoelectric 
transducer element, means composed of a combination of magnet and lead 
switch, etc. are considered to be employable. Moreover, it may be so 
arranged that, in the absence of copy paper sheets in the cassettes loaded 
in the copying apparatus, the signal for .phi..phi..phi..phi. is emitted, 
by providing, apart from the copy paper size detection means mentioned 
above, means for detecting the presence of the copy paper sheets 
including, for example, a light transmitting opening formed at a 
predetermined position of the cassette together with light emitting and 
light receiving elements. 
Referring to FIG. 7, the copying magnification detection means is so 
arranged as to obtain the predetermined signals through detection of 
displacement of the lens assembly L following alteration of the 
magnifications. More specifically, simultaneously with the change-over of 
the driving speeds for the exposure lamp l, reflecting mirrors m.sub.1 and 
m.sub.2, etc. following a suitable magnification change-over operation as 
described earlier, the lens assembly L is also moved to a predetermined 
position, at which time, the position of the lens assembly L is detected 
through microswitches SW.sub.5, SW.sub.6 and SW.sub.7 to be actuated as 
the lens assembly L is moved, and the signals obtained by the above 
detection are converted into predetermined magnification signals so as to 
be input to the random access memory RAM 208 through the interface I/O 210 
mentioned earlier. 
In the driving mechanism for the lens assembly L shown in FIG. 7, the 
driving force of a motor LM is transmitted to a pully P.sub.1 through 
gears g.sub.1 and g.sub.2 meshing with each other for moving a lens holder 
LH through movement of a lens assembly moving wire 61 passed around the 
pulley P.sub.1, and pulleys P.sub.2 and P.sub.3 rotatably provided 
adjacent to opposite ends of a base 60. The lens holder LH is slidably 
mounted on rails 62 and 63, while opposite ends of the wire 61 are 
connected to a projection or pin 64 integrally formed or rigidly secured 
to the lens holder LH. The lens holder LH is further provided with a 
switch actuating portion 65 so as to contact actuators of the 
microswitches SW.sub.5, SW.sub.6 and SW.sub.7 arranged at predetermined 
positions on the base 60 for actuating predetermined ones of the 
microswitches SW.sub.5 to SW.sub.7 to emit a lens assembly stopping signal 
and also a signal corresponding to each of the copying magnifications. 
The microswitches SW.sub.5 to SW.sub.7 are respectively disposed at the 
predetermined positions corresponding to the equal size magnification, 
contraction A and contraction B, which positions are optically determined 
based on the locations of the lens assembly L according to the copying 
magnifications. 
Although not particularly shown in the drawings, the copying magnification 
signal produced by the functioning of the respective microswitches 
SW.sub.5 to SW.sub.7 are formed into codes for each copying magnification 
through a suitable signal converting means (not shown) so as to be input 
to the random access memory RAM 208 mentioned earlier. 
It is to be noted here that, since some changeover operation is effected 
during the selection of the copying magnifications to be made by the 
operator, the signal obtained in the above case may be directly utilized 
as a copying magnification detection signal. 
It should also be noted that as is seen from the foregoing description, in 
the arrangement according to the present invention, the area to be covered 
by the copying operation or the area available for the copying operation 
is indicated on the original platform based on the size and copying 
magnification of the copy paper sheets ready for copying, and that the 
specific indication circuit, use of the micro-computer, programming 
thereof, detecting means for the copy paper sheet sizes and copying 
magnifications, etc. disclosed in the above embodiment may further be 
modified in various ways within the technical concept of the present 
invention. 
It should further be noted that although the foregoing embodiment has been 
mainly described with reference to the case of equal size magnification 
and reduced scale copying, the indication of the area available for the 
copying operation is also required in the case of a copying apparatus 
provided with an enlarging function (for example, at 1.414 power, i.e., 
approximately two power in area ratio), and that the present invention is 
also applicable to such enlargement. For example, the fact that an 
original of A4 size can not be used for the copy paper sheet of B4 size in 
the above copying magnification may be indicated by the indication of the 
area available for the copying operation or copying coverage at the 
indicating portion. 
As is clear from the foregoing description, according to the indication 
device of the present invention, through clear indication of the area 
available for the copying operation or copying coverage by the 
combinations of the copy paper sheet sizes and copying magnifications, 
which has conventionally been troublesome and difficult for the operators 
to determine, inconveniences such as use of a copy paper sheet 
unnecessarily large with respect to the original or employment of a copy 
paper sheet too small for the desired image are advantageously prevented, 
and furthermore, since it is possible to give instructions for copy paper 
size exchange if a copy paper sheet of unsuitable size is selected, 
wasteful use of the copy paper sheets is eliminated. Moreover, when the 
control as described above is arranged to be effected within the range of 
memorizing capacity of the micro-computer employed for the sequence 
control of the copying apparatus, accurate indication control may be 
effected without increase of the size of the copying apparatus or 
complication of the circuit due to the control mechanisms even when many 
kinds of copy paper sheet sizes and copying magnifications are involved. 
Although the present invention has been fully described by way of example 
with reference to the accompanying drawings, it is to be noted that 
various changes and modifications are apparent to those skilled in the 
art. Therefore, unless otherwise such changes and modifications depart 
from the scope of the present invention, they should be construed as 
included therein.