Copy magnification change apparatus in magnetic copying machine

In a magnetic copying machine, a reflected light from an original copy is converted into an electrical signal, and supplied to a magnetic recording head to form a magnetic latent image on a magnetic recording drum. The magnetic latent image is developed by a magnetic toner, and the toner picture is transferred onto a recording paper. The transferred toner picture is fixed on the recording paper, and the remaining toner on the surface of the magnetic recording drum is cleaned after the transfer operation. When the copy magnification factor is larger than one, the pulse interval of clock pulses generated in synchronization with the rotation of the magnetic recording drum for reading out the electrical signal is made longer than that used with actual-size copying, and the movement of the magnetic recording head in the axial direction of the magnetic recording drum per one revolution of the magnetic recording drum is made larger than that used with actual-size copying. When the copy magnification factor is smaller than one, the pulse interval of clock pulses generated in synchronization with the rotation of the magnetic recording drum for reading out the electrical signal is made shorter than that used with actual-size copying, and the movement of the magnetic recording head in the axial direction of the magnetic recording drum per one revolution of the magnetic recording drum is made shorter than that in the actual-size copy.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a copy magnification change apparatus in a 
magnetic copying machine, and more particularly to a copy magnification 
change apparatus in a magnetic copying machine which can be suitably 
applied to a magnetic duplicator by which numerous copies can be 
automatically and speedily obtained from one original copy. 
2. Description of the Prior Art 
The Japanese Patent Publication No. 19793/1963 discloses a magnetic copying 
machine in which an image of a document is recorded as a magnetic latent 
image on a recording drum by a magnetic head, the magnetic latent image is 
sequentially developed, transferred and fixed onto a recording paper to 
obtain a copy. In the magnetic copying machine, the image of the document 
can be recorded as the magnetic latent image in enlargement on the 
recording drum. The ratio of a diameter of a document winding drum to a 
diameter of the recording drum is predetermined for enlargement. Further, 
the ratio of a speed of read-out means to a speed of the magnetic head in 
horizontal direction is predetermined for enlargement by a gear speed 
change mechanism. Generally, when a magnetic copying machine has copy 
enlarging function and/or copy reducing function, it is desired that it 
has further actual-size copying (magnification factor: 1) function. For 
example, when a copy of A4-size is obtained from a document of B4-size by 
a magnetic copying machine, it is desired that a copy of A4-size can be 
obtained from a document of A4-size by the same magnetic copying machine 
and that the copy magnification factor can be easily changed over by 
simple operation, for example, by operation of a switch arranged on a 
panel. In the above-described prior art, for example, the ratio of the 
diameter of the one drum to that of the other drum should be changed for 
different magnification factors. That is not simple operation. 
Further in an electro-static copying machine using Xerography method, a 
lens system should be moved for copy enlargement and copy reduction by a 
complicated mechanism. Since copy magnification is changed in mechanical 
manner, changing operation of copy magnification requires much time. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a copy magnification change 
apparatus in a magnetic copying machine which overcomes the 
above-described defects of the conventional copying machine, and in which 
copy magnification can be changed by simple operation. 
Another object of this invention is to provide a copy magnification change 
apparatus in a magnetic copying machine which is simple in mechanical 
construction, and copy magnification can be changed only with electrical 
control and moreover can be instantaneously changed over. 
A further object of this invention is to provide a copy magnification 
change apparatus in a magnetic copying machine in which copy 
magnifications can be differently changed in the primary scanning 
direction and the secondary scanning direction. 
A still further object of this invention is to provide a copy magnification 
change apparatus in a magnetic copying machine in which at least two of 
different enlargements, reductions and actual-size copy operation can be 
selected for a desired copy edition for a single document. 
In accordance with an aspect of this invention, a copy magnification change 
apparatus in a magnetic copying machine in which light from a document is 
converted into an electrical video signal by photoelectric converting 
means, the video signal is supplied to a magnetic head moving along the 
axial direction of a magnetic recording drum to form a magnetic latent 
image onto the magnetic recording drum; the copy magnification change 
apparatus comprising: (a) means for generating clock pulses to be supplied 
to the photoelectric converting means in synchronization of rotation of 
the magnetic recording drum to read out the electrical video signal from 
the photoelectric converting means, the pulse interval of the clock pulses 
for copy magnification factor larger than one being longer than that of 
the clock pulses for actual-size copy operation; (b) another means for 
increasing the movement length of the magnetic head along the axial 
direction of the magnetic recording drum for one line read-out of the 
photoelectric converting means for copy magnification factor larger than 
one in comparison with actual-size copy operation. 
Various other objects, advantages and features of the present invention 
will become readily apparent from the ensuing detailed description, and 
the novel features will be particularly pointed out in the appended claims 
.

DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS 
FIG. 1A to FIG. 4 show the principle of a magnetic duplicator according to 
one embodiment of this invention. FIG. 1A and FIG. 2 show an image pick-up 
portion of the duplicator. In FIG. 1A and FIG. 2, an original copy, a 
drawing or a document 12 is supported face down on a document support 11 
which comprises a transparent (e.g., glass) uniform plate. A part of the 
document 12 is irradiated by light sources 13 such as fluorescent lamp. 
Light from the light sources 13 is reflected by the surface of the 
document 12, further by mirrors 17 and 18 and converged onto a 
photoelectric conversion element or an image pick-up element 16 such as a 
CCD (Charge-Coupled Device) by a lens 15. Thus, a real image is formed on 
the CCD 16. A portion of the real image formed on an effective width of 
the CCD 16 is converted into an electrical video (picture) signal. The 
document support 11 supporting the document 12 is moved relatively 
(secondary scan) to the lamp 13 the lens 15 and the CCD 16 to obtain the 
picture signals on the whole surface of the document 12. 
The light source 13, the lens 15, the CCD 16 and the mirrors 17 and 18 are 
mounted on a secondary scanning carriage 14 for the secondary scanning. 
The secondary scanning carriage 14 is so designed as to be movable in the 
rightward and leftward directions (FIG. 1A). Both ends of a wire 20 are 
fixed to the secondary scanning carriage 14. The wire 20 is wound on a 
pair of pulleys 21 and 22. Drive force of a pulse motor 23 as a drive 
source for the secondary scanning of the image pickup portion is 
transmitted through the pulley 21 and wire 20 to the secondary scanning 
carriage 14 to drive the latter in the rightward and leftward directions. 
As shown in FIG. 2, clock pulses from a clock generator 25 are supplied 
through a CCD control circuit 26 to the CCD 16 to obtain the video signal 
from the latter. The output of the CCD is supplied through a video 
amplifier 27 to a recording portion of the duplicator. 
FIG. 1B and FIG. 3 show the recording portion of the duplicator. In FIG. 
1B, a magnetic recording drum 31 constituting a magnetic recording medium 
is rotated in the clockwise direction as shown by the arrow. The picture 
signal obtained from the video amplifier 27 of the image pick-up portion 
shown in FIG. 1A is supplied through a magnetic head control circuit 33 to 
a magnetic head 32. A magnetic latent image is formed on the recording 
drum 31 by the magnetic head 32. The magnetic latent image is developed by 
a toner development device 30. 
The magnetic head 32 is mounted on a secondary scanning support 34 for the 
secondary scanning of the recording portion. The secondary scanning 
support 34 is so designed as to be movable in the leftward and rightward 
directions (FIG. 3), namely in the axial direction of the recording drum 
31. Both ends of a wire 38 are fixed on the secondary scanning support 34. 
The wire 38 is wound on a pair of pulleys 35 and 36. A drive force of a 
pulse motor 39 as a drive source for the secondary scanning of the 
recording portion is transmitted through a pulley 35 and the belt 38 to 
the secondary scanning support 34 to drive the latter in the axial 
direction of the recording drum 31. 
A rotary encoder 41 is combined with a rotary shaft of the recording drum 
31. Then rotary encoder 41 constitutes a part of the clock generator 25 
shown in FIG. 2. One index pulse is generated per one revolution of the 
recording drum 31 from the rotary encorder 41. Numerous clock pulses are 
generated between the index pulses. 
On the other hand, referring to FIG. 1B, a record paper 45 is led into a 
record paper transport path 47 shown by dotted line from a paper supply 
elevator 48 by a feed roller 46, and it is introduced into the gap between 
the recording drum 31 and a transfer roller 49 by means of guide rollers 
(not shown). Paper guide members 51 and 52 are arranged for forming the 
transport path 47. While the record paper 45 passes between the recording 
drum 31 and the transfer drum 49, the toner image is transferred onto the 
record paper 45. The record paper 45 is further transported along the 
transport path and the toner image is fixed on the record paper 45 between 
fixing rollers 55 and 56 of a fixing device. Then, it is discharged into a 
copy receiver 57. The remaining toner on the recording drum 31 after the 
above described transferring operation is removed by a cleaning blade 61 
and an air accumulator 62 of a cleaning device. The latent image on the 
recording drum 31 is erased by an erasing head 63 which extends over the 
whole width of the recording drum 31, before a next latent image is formed 
on the recording drum 31. 
A primary scanning direction in the latent image formation is in the 
direction extending from a point A to another point B on the document 12 
shown in FIG. 2 with respect to the image pickup portion, while it is in 
the peripheral direction of the recording drum 31 shown in FIG. 1B with 
respect to the recording portion. One line of the pirmary scanning is 
effected in one revolution of the recording drum 31. While one line of the 
primary scanning for the image pickup and latent image formation is 
effected, one line of the secondary scanning of the image pickup portion 
and recording portion is effected. The secondary scanning of the image 
pickup portion is effected by moving the secondary scanning carriage 14 
shown in FIG. 1A in the direction shown by the arrow 19, while the 
secondary scanning of the recording portion is effected by moving the 
secondary scanning support 34 shown in FIG. 3 in the direction shown by 
the arrow 40. The primary scanning direction and the secondary scanning 
direction are shown in FIG. 4 with respect to a document 12 of A4-size. 
The whole surface of the document 12 is scanned by repeating the above 
primary and secondary scannings. Thus, the magnetic latent image 
corresponding to the document 12 is formed on the recording drum 31. 
Next, there will be described sequential operations of the duplicator shown 
in FIG. 1 to FIG. 4. 
Duplication or copy starts with a copy (duplicating) switch. First, the 
magnetic latent image on the recording drum 31 is erased. Next, the image 
pick-up portion operates for photoelectric conversion to obtain the 
picture signal. The picture signal is converted into a magnetic signal, 
and recorded as the latent image on the recording drum 31. Next, it is 
checked whether the scanning of the document is completed or not. The 
latent image formation mode is completed with the confirmation of the 
completion of the scanning of the document. The copy mode follows. 
In the copy mode, paper feeding, development, transfer and fixing are 
effected in order, and a copy of the document is obtained. After the 
transfer, cleaning of the recording drum 31 is effected in concurrence 
with the fixing. A series of the paper feeding, development, transfer, 
fixing, and cleaning is repeated, until the number of the obtained copies 
reaches a predetermined or desired number. When the copies of the desired 
number are obtained, the copying operation automatically ends. Next, there 
will be described methods of change of copy magnification, namely of copy 
enlargement and copy reduction of document. 
First, enlargement and reduction in the primary scanning direction in the 
primary scanning direction will be described with reference to FIG. 1 to 
FIG. 6. 
FIG. 5(a) represents a CCD 16. Positions A, B and C on the document support 
11 in FIG. 2 are projected on positions a.sub.0, b.sub.0 and c.sub.0 on 
the CCD 16, respectively. It is assumed that a document of A4-size (210 mm 
wide) is projected on an a.sub.0 -b.sub.0 region of the CCD 16, and that a 
document of B4-size (257 mm wide) is projected on an a.sub.0 -c.sub.0 
region of the CCD 16. For example, when the CCD 16 is constituted by 2048 
bits, the width of 257 mm corresponds to 2048 bits, and the width of 210 
mm corresponds to 1673 bits. A clock channel CH1 of the rotary encoder 41 
generates 2048 clock pulses (regular intervals) shown in FIG. 5(c) per one 
revolution of the recording drum 31 (FIG. 5(b)). The clock pulses of the 
channel CH1 are used as read-out pulses for the CCD 16. The image on the 
CCD 16 (FIG. 5(a)) is recorded on the recording drum 31 in the manner 
shown in FIG. 5(d). The a.sub.0 -c.sub.0 region of the CCD 16 corresponds 
to an a.sub.1 -c.sub.1 region of the recording drum 31. Peripheral 
positions x and times t at which the image is recorded on the recording 
drum 31 are determined by the rotary encoder 41 in accordance with the 
rotation of the recording drum 31. A time t(1) corresponds to a position 
a.sub.1. A time (1673) corresponds to a position b.sub.1. A time (2048) 
corresponds to a position c.sub.1. Intermediate times t correspond 
proportionally to intermediate positions x, respectively. When the length 
of the a.sub.1 -c.sub.1 region is 257 mm, the width A-C of the document 
(257 mm) projected on the a.sub.0 -c.sub.0 region of the CCD 16 is 
recorded in actual size on the recording drum 31. The width A-B of the 
document (210 mm) is recorded in actual size on the a.sub.1 -b.sub.1 
region of the recording drum 31. 215/257 is equal to 1673/2048. The length 
of the CCD 16 corresponds to the width of the document support 11, and to 
the length of the periphery of the recording drum 31. However, the length 
of the periphery of the recording drum 31 is somewhat larger than the 
width of the B4-size, and it is 270 mm. 
A clock channel CH2 of the rotary encoder 41 generates 1673 clock pulses 
(FIG. 5(e)) per one revolution of the recording drum 31. When the clock 
pulses of the clock channel CH2 are used as read-out pulses for the CCD 
16, video signals are obtained only from 1673 bits of the CCD 16 per one 
revolution of the recording drum 31. In other words, the image projected 
on the a.sub.0 -b.sub.0 region of the CCD 16 is recorded on an a.sub.2 
-b.sub.2 region of the recording drum 31 (FIG. 5(f)). The width (210 mm) 
of the A4-size is projected on the a.sub.0 -b.sub.0 region of the CCD 16. 
Since the length of the a.sub.2 -b.sub.2 region is equal to the length of 
the a.sub.1 -c.sub.1 region (257 mm), the document 12 of the width of 210 
mm is so recorded on the recording drum 31 as to be enlarged to the width 
of 257 mm. Thus, A4-size is enlarged to B4-size. 
A clock channel CH3 of the rotary encoder 41 generates 2506 clock pulses 
(FIG. 5(g)) per one revolution of the recording drum 31. When the clock 
pulses of the clock channel CH3 are used as read-out pulses for the CCD 
16, the image projected on the a.sub.0 -c.sub.0 region (2048 bits) of the 
CCD 16 is recorded on an a.sub.3 -c.sub.3 region of the recording drum 31 
(FIG. 5(h)). Since 2048/2506 is equal to 210/257, the length of the 
a.sub.3 -c.sub.3 region is equal to 210 mm. The a.sub.0 -c.sub.0 region 
includes a video information of the document 12 of the width 257 mm. 
Accordingly, the width of 257 mm is reduced to the length of the a.sub.3 
-c.sub.3 region (210 mm). In other words, B4-size is reduced to A4-size. 
In order to facilitate the description, the first channel CH1 generates 
2048 clock pulses, the second channel CH2 generates 1673 clock pulses and 
the third channel CH3 generates 2506 clock pulses, per one revolution of 
the recording drum 31. However, it is more convenient in an actual 
duplicator that the numbers of clock pulses of the first, second and third 
channels CH1, CH2 and CH3 are somewhat different from the above described 
numbers. The reason will be hereinafter described with reference to FIG. 
10 and FIG. 11. 
In the above description, the rotary encoder 41 generates the index pulses 
and the three trains of clock pulses. However, the rotary encoder 41 may 
be so designed as to generate the index pulses and only one train of clock 
pulses. In that case the one train of clock pulses is used as a reference 
clock for a PLL (Phase Locked Loop) circuit shown in FIG. 6. A train of 
clock pulses for another channel is generated by the PLL circuit of FIG. 
6. 
The PLL circuit consists of a phase detector 71, a low pass filter 72, an 
amplifier 73, a voltage control oscillator 74, a 1/N.sub.1 divider 75 and 
a 1/N.sub.2 divider 76. For example, when the rotary encoder 41 generates 
2200 clock pulses as reference clock per one revolution of the recording 
drum 31, and N.sub.1 and N.sub.2 are 9 and 11, respectively, a train of 
1800 clock pulses per one revolution for the second channel is obtained 
from the PLL circuit. 
Instead of the rotary encoder 41, clock pulses may be magnetically recorded 
on one part of the recording drum 31. The reproduced clock pulses are used 
as the read-out pulses for the CCD 16. Or when a drive source for the 
recording drum 31 is a synchronous motor, read-out pulses for the CCD 16 
can be obtained from an oscillator for driving the synchronous motor. 
Next, there will be described enlargement and reduction in the secondary 
scanning direction with reference to FIG. 1 to FIG. 4 and FIG. 7. 
One step of the secondary scanning is taken per one revolution of the 
recording drum 31. The pulse motor 23 shown in FIG. 1A and the pulse motor 
39 shown in FIG. 3 are used as drive source for the secondary scanning. 
The secondary scanning carriage 14 (FIG. 1A) and support 34 (FIG. 3) are 
moved by 0.02 mm with one phase advance pulse. Accordingly, when five 
phase advance pulses (FIG. 7(b)) are supplied to the pulse motor 23 per 
one revolution of the recording drum 31, the secondary scanning carriage 
14 for image pickup is moved by 0.02 mm.times.5=0.1 mm. Similarly, when 
five phase advance pulses (FIG. 7(b)) are supplied to the pulse motor 39 
per one revolution of the recording drum 31, the record portion is moved 
by 0.02 mm.times.5=0.1 mm. Thus, copy of actual size is obtained. 
On the other hand, when six phase advance pulses (FIG. 7(c)) are supplied 
to the pulse motor 39 per one revolution of the recording drum 31, the 
recording portion is moved by 0.02 mm.times.6=0.12 mm. Thus, the recording 
portion is moved longer by 20% than the image pickup portion. As the 
result, A4-size is enlarged nearly to B4-size in the secondary scanning 
direction. 
When four phase advance pulses (FIG. 7(d)) are supplied to the pulse motor 
39 per one revolution of the recording drum 31, the recording portion is 
moved by 0.02 mm.times.4=0.08 mm. Accordingly, the recording portion is 
moved shorter by 20% than the image pickup portion. As the result, B4-size 
is reduced nearly to A4-size in the secondary scanning direction. 
Speed increase rates or speed reduction rates of transmission mechanisms 
for the pulse motors 23 and 39 can be arbitrarily varied, and further the 
number of phase advance pulses per one revolution of the recording drum 31 
can be arbitrarily varied. Accordingly, the copy magnification in the 
secondary scanning direction can be arbitrarily varied. 
The moving length in the secondary scanning direction per one revolution of 
the recording drum 31 is varied with the number of the phase advance 
pulses. However, transmission systems different in speed increase rate or 
speed reduction rate may be provided for varying the moving length. In 
that case, the systems are changed over by electro-magnetic clutches. A 
servo motor may be used instead of the pulse motor. 
When the spacing between the secondary scanning lines is variable, an 
electro-static copying machine has the defect that a recorded image become 
unnatural in accordance with the diameter of a recording stylus. However, 
the defect of the electrostatic copying machine is removed by the magnetic 
duplicator of this invention in which the core thickness of the magnetic 
head 32 is so designed as to be larger than the maximum spacing between 
the secondary scanning lines, as described in the U.S. Pat. No. 4,072,957. 
In that case, the recording drum is scanned in overlap by the difference 
between the core thickness of the magnetic head 32 and the spacing between 
the secondary scanning lines. 
FIG. 8 shows one example of a control circuit in which the copy 
magnification is selected by change-over of switches arranged in an 
operating panel. 
A switch S.sub.1 for actual size is connected through an invertor INV.sub.1 
to an AND circuit AND.sub.1. When the switch S.sub.1 is closed, the clock 
pulses CH1 of the first channel are supplied as the read-out clock through 
the AND circuit AND.sub.1 and OR gate OR.sub.1 to the CCD 16. 
A switch S.sub.2 for A4.fwdarw.B4 enlargement is connected through an 
inverter INV.sub.2 to an AND circuit AND.sub.2. When the switch S.sub.2 is 
closed, the clock pulses CH2 of the second channel are supplied as the 
read-out clock through the AND circuit AND.sub.2 and the OR gate OR.sub.1 
to the CCD 16. 
A switch S.sub.3 for B4.fwdarw.A4 reduction is connected through an 
inverter INV.sub.3 to an AND circuit AND.sub.3. When the switch S.sub.3 is 
closed, the clock pulses CH3 of the third channel are supplied as the 
read-out clock through the AND circuit AND.sub.3 and the OR gate OR.sub.1 
to the CCD 16. 
The three trains of five clock pulses, six clock pulses and four clock 
pulses per one revolution of the recording drum 31 are generated from a 
secondary scanning clock circuit 81 on the basis of the index pulse and 
the clock pulse of the first channel CH1. They are supplied to AND 
circuits AND.sub.4, AND.sub.5 and AND.sub.6, respectively. One of the 
three trains of clock pulses is selectively supplied through the 
corresponding one of the AND circuits AND.sub.4, AND.sub.5 and AND.sub.6 
to an OR gate OR.sub.2 with the selective closing of the switches S.sub.1, 
S.sub.2 and S.sub.3. It is further supplied through the OR gate OR.sub.2 
and a ring counter 82 for the record secondary scanning to the pulse motor 
39 for the recording portions. On the other hand, in the image pickup 
portion, the train of five clock pulses per one revolution of the 
recording drum 31 is supplied through another ring counter 83 for the 
image pickup secondary scanning to the pulse motor 23 for the image pickup 
portion. As understood from the above description of FIG. 5 and FIG. 7, 
actual size copy, enlargement and reduction are effected with the control 
circuit of FIG. 8. 
Five phase advance pulses per one revolution of the recording drum 31 have 
been supplied to the pulse motor 23 for one step of the image pickup 
secondary scanning, while five, six or four phase advance pulses per one 
revolution of the recording drum 31 have been supplied to the pulse motor 
39 for one step of the record secondary scanning for the actual size copy, 
enlargement or reduction. However, on the contrary, five phase advance 
pulses per one revolution of the recording drum 31 may be supplied to the 
pulse motor 39 for one step of the record secondary scanning, while five, 
six or four phase advance pulses per one revolution of the recording drum 
31 may be supplied to the pulse motor 23 for one step of the image pickup 
secondary scanning for the actual size copy enlargement or reduction. 
Next, there will be described another principle of the enlargement and 
reduction in the primary scanning direction with reference to FIG. 1 to 
FIG. 4 and FIG. 9 to FIG. 11. 
As shown in FIG. 9, the periphery of the recording drum 31 consists of a 
record portion L (a.sub.1 -c.sub.1 region, for example, 257 mm long) which 
is used for copy, and a non-record portion M (c.sub.1 -a.sub.1 region, for 
example, 18 mm long) which is not used for copy. The non-record portion M 
is necessary for stable running of recording paper. On the other hand, 
clock pulses more than the number of the bits of the CCD 16 should be 
applied to the CCD 16 in order to stably take out video informations from 
the CCD 16. For example, when the number of the bits of the CCD 16 is 
2048. the number of the clock pulses is 2078. For that purpose, the number 
of pulses of the rotary encoder 41 per one revolution is actually 2200. 
When A-C (257 mm) of the document of B4-size as shown in FIG. 2 is 
projected onto the a.sub.0 -c.sub.0 region of the CCD 16 of 2048 bits, the 
number of the clock pulses of the first channel CH1 per one revolution is 
2200 as shown in FIG. 10(c). The number of the clock pulses is larger than 
the number of the bits of the CCD 16. The video information corresponding 
to the width (257 mm) of the B4-size document 12 is obtained from 2048 
bits of the CCD 16. When the video information is recorded on the a.sub.1 
-c.sub.1 region (257 mm) of the recording drum 31 as shown in FIG. 5 and 
FIG. 9, actual size copy is obtained. The timing of the above described 
pulses is shown in FIG. 10(a), FIG. 10(b) and FIG. 10(c). 
FIG. 10(a) shows the index pulses. One index pulse is generated per one 
revolution of the recording drum 31. FIG. 10b shows the recording area 
pulse. During the time when the recording drum 31 is used for copy, the 
level of the recording area pulse is at "1". This time corresponds to the 
portion L shown in FIG. 9. During the time when the recording drum 31 is 
not used for copy, the level of the recording area pulse is at "0". This 
time corresponds to the portion M shown in FIG. 9. 
Next, there will be described method of enlargement in the primary scanning 
direction according to the above other principle. 
For example, when the width A-B (210 mm) of the A4-size document is 
projected onto the a.sub.0 -b.sub.0 region of the CCD 16, as shown in FIG. 
2, the video information of the width A-B of the document is obtained in 
1673 bits. When the CCD 16 is driven by 1800 pulses per one revolution of 
the recording drum 31, the video information is recorded on the region 
a.sub.2 -b.sub.2 (257 mm) of the recording drum 31, as shown in FIG 5(f). 
Referning to FIG. 10, FIG. 10(d) shows 1800 pulses per one revolution of 
the recording drum 31. 1673 pulses of 1800 pulses correspond to the "1" 
period of the recording area pulse of FIG. 10(b). Accordingly, the video 
information of the first bit to 1673rd bit is recorded on the length of 
257 mm of the recording drum 31. Thus, the width 210 mm is enlarged to the 
B4-size width 257 mm. This fact is equal to the principle of FIG. 5. 
On the other hand, clock pulses more than the number of the image pickup 
bits of the CCD should be supplied to the CCD in order to stably operate 
the latter. For that purpose, clock pulses (FIG. 10(e)) four times as 
frequent as the clock pulses of FIG. 10(d) are provided. The frequency is 
1800.times.4=7200 pulses. When the necessary video information has been 
obtained in 1673 bits of the CCD 16, the drive clock for the CCD 16 is 
changed over from the clock of FIG. 10(a) into the other clock of FIG. 
10(e) for the "0" period of the recording area pulse of FIG. 10(b). 
Accordingly, the clock pulses of the number represented by the following 
equation (1) are supplied to the CCD 16 during one revolution of the 
recording drum 31: 
EQU 1673+(1800-1673).times.4=2181 (1). 
The number 2181 is larger than the image pickup bit number 2048 of the CCD 
16. Accordingly, the CCD 16 can be stably operated. 
The clock CH2 of FIG. 10(d) is used during the "1" period of the recording 
area pulse shown in FIG. 10(b) so that the image of the document is 
recorded in enlargement on the recording drum 31. The clock four times as 
frequent as the clock CH2, as shown in FIG. 10(e), is used during the "0" 
period of the recording area pulse. As the result, the clock CH2' shown in 
FIG. 10(f), namely 2181 pulses per one revolution of the recording drum 
31, are used. Actually, the clock CH2' is used for driving the CCD 16, 
instead of the clock CH2 of FIG. 8. 
For example, a pulse generating circuit shown in FIG. 11 is used for 
producing the clock CH2' of FIG. 10(f) from the clock CH2 of FIG. 10(d). 
In the circuit of FIG. 11, the clock CH2 is supplied to a frequency 
multiplier (.times.4) 91. 7200 clock pulses as shown in FIG. 10(e) are 
produced by the frequency multiplier 91. 1800 clock pulses are supplied to 
one input terminal of an AND gate AND.sub.7. Q-output of a flip-flop 
FF.sub.1 is supplied to another input terminal of the AND gate AND.sub.7. 
The output of the frequency multiplier 91 is supplied to one input 
terminal of an AND gate AND.sub.8. Q-output of the flip-flop FF.sub.1 is 
supplied to another input terminal of the AND gate AND.sub.8. 1800 clock 
pulses are further supplied to a counter 92. The counter 92 starts to 
count the clock pulses in synchronization with the index pulse. When the 
counter 92 has counted 1673 pulses, it inverts the flip-flop FF.sub.1 to 
put the Q-output into "1". The Q-output of the flip-flop FF.sub.1 is "1" 
during the time from the first pulse of the clock CH2 to the 1673rd pulse 
thereof with reference to the index pulse. The clock pulses of the clock 
CH2 are produced at the output terminal of the AND gate AND.sub.7. During 
that time, the output of the AND gate AND.sub.8 is zero. Accordingly, 
clock pulses of the clock CH2 are obtained from an OR gate OR.sub.3. 
Then, the Q-output of the flip-flop FF.sub.1 becomes "1" from the 1674th 
pulse of the clock CH2. Clock pulses four times as frequent as the clock 
pulses of the clock CH2 are produced at the output terminal of the AND 
gate AND.sub.8. During that time, the output of the AND gate AND.sub.7 is 
zero. Accordingly, the four times clock pulses are obtained from the OR 
gate OR.sub.3. As the result, 2181 pulses as shown by the equation (1) are 
totally produced between the adjacent index pulses from the circuit of 
FIG. 11. 
It will be understood that the recording area pulse of FIG. 10(b) may be 
used in the circuit of FIG. 11 instead of the counter 92 and the flip-flop 
FF.sub.1 to effect the above described operation. 
Next, there will be described method of reduction in the primary scanning 
direction according to the other principle shown in FIG. 10. 
In this case, there will be used the 2700 clock pulses per one revolution 
of the recording drum 31 as shown in FIG. 5(g). 
When the image of the B4-size (257 mm) document is projected onto the 
a.sub.0 -c.sub.0 region (2048 bits) of the CCD 16, and the clock CH3 of 
2700 pulses per one revolution of the recording drum 31 is used, the 
corresponding latent image is recorded in reduction to about 210 mm 
(A4-size) on the a.sub.3 -c.sub.3 ragion of the recording drum 31 as shown 
in FIG. 5(h). Since the number of the read-out pulses (2700) per one 
revolution of the recording drum 31 is further larger than the number of 
the image pickup bits (2048), the CCD 16 stably operates. 
Next, there will be described a modification to improve resolution of 
read-out, with reference to FIG. 12 and FIG. 13. Referring to FIG. 12, two 
CCDs 16a and 16b are used for reading out one half D-O of the document and 
another half O-E of the document, respectively. The number of the image 
pickup bits is 2048.times.2. Accordingly, the number of the image pickup 
clock pulses is twice as large as that of the image pickup pulses for the 
one CCD 16, and therefore it is 2200.times.2=4400. The images on the CCDs 
16a and 16b can be read out with 4400 clock pulses per one revolution of 
the recording drum. FIG. 13 shows the timing relationships among different 
pulses. 
In this modification, the image of the document 12 (B4-size) is divided 
into two. The two are projected onto the CCDs 16a and 16b, respectively. A 
point D of the document 12 is projected onto a point d.sub.0 (the first 
bit) of the one CCD 16a, while a central point O of the document 12 is 
projected onto a point O.sub.0-1 (the 2048th bit) of the one CCD 16a. 
Intermediate points between the points D and O are projected onto 
intermediate points (intermediate bits) between the points d.sub.0 and 
O.sub.0-1. Clock pulses CH4 shown in FIG. 13(c) are used for the CCD 16a. 
The CCD 16a is so driven that the video signal from the first bit of the 
CCD 16a is recorded on the start of the record area of the recording drum 
31 as shown in FIG. 13(d). 
Similarly, the other half O-E of the document 12 is projected onto a region 
O.sub.0-2 -e.sub.0 of the other CCD 16b. A point O of the document 12 is 
projected onto the first bit of the CCD 16b. A point E of the document 12 
is projected onto the 2048th bit of the CCD 16b. The CCD 16b is so driven 
that video signals are read out from the CCD 16b in the timing shown in 
FIG. 13(e). The first bit corresponds to the center of the record area of 
the recording drum 31. The 2048th bit corresponds to the end of the record 
area of the recording drum 31. Thus, the document is copied in actual 
size. 
Next, there will be described enlargement operation 
(A4-size.fwdarw.B4-size). 
1800.times.2=3600 pulses per one revolution of the recording drum 31 are 
used for the enlargement operation. The document 12 is put onto the center 
of the surface of the document support in the manner shown in FIG. 12. One 
half of the document 12 is projected onto the one CCD 16a, while another 
half of the document 12 is projected onto the other CCD 16b. In other 
words, an F-O region of the A4-size document 12 is projected onto an 
F.sub.0 -O.sub.0-1 region of the CCD 16a. The position f.sub.0 corresponds 
to the 375th bit of the CCD 16a, since the A4-size corresponds to the 1673 
bits, and 2048 minus 1673 is equal to 375. The image of the F-O region of 
the A4-size document 12 is projected onto the region between the 375th bit 
and the 2048th bit of the CCD 16a. 
Similarly, the other half O-G of the A4-size document 12 is projected onto 
an O.sub.0-2 -g.sub.0 region of the CCD 16b which corresponds to the 
region between the first bit and the 1673rd bit. 
The timing relationship between clock pulses for the CCDs 16a and 16b is 
shown in FIG. 13(h) and (i). The CCDs 16a and 16b are so driven that the 
video-signals from them are recorded on the record area of the recording 
drum 31. In the manner shown in FIG. 10(f), a d.sub.0 -f.sub.0 region of 
the CCD 16a and g.sub.0 -e.sub.0 region of the CCD 16b which correspond to 
the non-record area of the recording drum 31 are driven with the more 
frequent clock (four times). As shown in FIG. 13(h) and (i), the CCD 16a 
is driven from the first bit to the 374th bit with the more frequent clock 
(3600.times.4), and it is driven from the 374th bit to the 2048th bit with 
the normal clock (3600). The other CCD 16b is driven from the first bit to 
the 1673rd bit with the normal clock (3600), and it is driven from the 
1674th bit to the terminal bit with the more frequent clock. Since pulses 
more than 2100 per half revolution of the recording drum 31 are applied to 
the CCDs 16a and 16b, they can stably operate. The exposure times are the 
same for the CCDs 16a and 16b. Further, the exposure time for the 
enlargement operation is nearly equal to that for the actual size copy 
operation. Accordingly, the outputs of the CCDs 16, 16a and 16b are 
maintained constant. A control circuit for the above described operation 
may be nearly equal to that of FIG. 11. 
Similarly in reduction operation, 2700.times.2=5400 pulses per one 
revolution of the recording drum 31 are used for the CCDs 16a and 16b. 
When the document is put onto the center of the document support, the 
control of the CCDs 16a and 16b can be facilitated as the enlargement 
operation. 
Although there have been described the typical enlargement ratio and 
reduction ratio, it will be understood that arbitrary enlargement ratio 
and reduction ratio are possible on the basis of the principle of this 
invention. 
Further, it will be understood that different copy magnifications can be 
selected in the primary scanning direction and the secondary scanning 
direction, and that different copy magnifications (enlargement ratios and 
reduction ratios) can be selected for a desired copy edition of one 
document. 
While the preferred embodiment has been described, variations thereto will 
occur to those skilled in the art within the scope of the present 
inventive concepts which are delineated by the following claims.