Image forming apparatus with adjustable light source

Image forming apparatus is provided with a rotating body, a device to form an image on the rotating body, a device to transfer an image formed by the image forming device onto a transfer member, and a light source to radiate light over the rotating body controller controls the power supply to the light source prior to image formation to thereby control the quantity of light from the light source before commencement of image formation. The rotating body is rotated in such a manner that after power supply control by the controller, no image is formed at a bright and dim light quantity changeover position with respect to the rotating body.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
This invention relates to an image forming device such as a transfer type 
copying machine, etc. 
2. Description of the Prior Art 
In the conventional transfer type electrophotographic devices, 
photosensitive changes occur if photosensitive elements are left without 
using them for many hours. Such sensitivity changes include long-term 
changes such as deterioration in response in relation to the life of 
photosensitive elements and so on as well as temporary ones attributable 
to moisture absorption, influence of residual surface charge and 
irregularities in sensitivity due to leak light, etc. As a means of 
solving these problems, it has been proposed, prior to proceeding to a 
process sequence, to provide a photosensitive element with light 
beforehand for a specified time and, in so doing, cause it to rotate so as 
to maintain the sensitivity (response) of the photosensitive element at a 
certain level or make it uniform. 
However, especially when preliminary exposure is performed for many hours 
directly before the commencement of a first sheet cycle, or when it is 
performed with a strong light source, there has been a possibility of an 
initial deterioration of the photo-sensitive characteristics (response) of 
the photosensitive material due to a fatigue of the rotating 
photosensitive element, resulting in the deterioration of the latent image 
of the first sheet. 
Further, there has also been such a possibility when a strong light source 
is employed to eliminate a residual image after transfer. On the other 
hand, however, if pre-exposure is started before a fixed time of image 
formation and image exposed during pre-exposure, an image may be formed at 
the boundary between preexposed and non-preexposed planes, resulting in 
the possibility of irregularities being produced in the first sheet. 
Further, in cases where preexposure as mentioned above and postexposure 
after image formation are carried out in a small copying apparatus, the 
distance between the document platen glass, optical system, photosensitive 
element, etc. and the light sources for pre- and post-exposure is made 
shorter and there is the possibility of the platen glass, etc. being 
heated and broken due to temperature rise of the light sources. 
Such possibility has been greater especially in the case of a compact type 
apparatus where bar lens or optical fiber is employed as the optical 
system for image exposure on the rotating photosensitive element due to 
the extreme proximity of the platen glass to the rotating photosensitive 
element. Further, there has been a danger especially when strong halogen 
lamps are employed as light sources for pre- and post-exposure. 
On the other hand, when making the transfer type apparatus smaller in size, 
it is necessary to provide essential means for the execution of the 
process in quite close order and accordingly, so that providing the means 
for pre- and post-treatment of the photosensitive element makes the 
apparatus more complicated and causes inconvenience of maintenance; for 
such reasons, real miniaturization has almost been hopeless. 
On the other hand, there has been an apparatus in which the rotating 
element contributing to transfer is rotated, after power-on to the 
apparatus, for pre-exposure or cleaning. 
On the other hand, in ordinary copying apparatuses, if power is switched on 
prior to the beginning of use, the apparatus itself diagnoses as to 
whether the condition suitable for copying is existing and no copying is 
effected if various requirements are not met. Such requirements include 
the availability of transfer material, developer and key counter, etc. and 
heater temperature at the fixing roller, etc. Especially, the temperature 
of the fixing roller at the time of power switch ON is not at a 
temperature making fixing possible nearly at each time. 
Accordingly, if rotation of the rotating body is caused to follow various 
factors mentioned above, rotation time or number of rotations may extend 
over many hours and for this reason, there has been the possibility of 
deterioration of photosensitivity as previously mentioned or damage to the 
surface of the rotating body. In addition, standby time till the 
commencement of exposure becomes long, resulting in impeding speedup of 
copying work. 
Further, it has hitherto been known that in a transfer type of copying 
apparatus, if a jammed sheet condition is detected, all the sheet feed 
members inclusive of the rotating body and fixing rollers, etc. are 
stopped so as to prevent a further aggravated condition of jammed sheet. 
In such a case, jamming occurs mostly during a copy cycle and therefore the 
electric potential at the rotating body is not uniform. Especially, on the 
surface of the rotating body from the charger to the discharger such as 
light source, etc. downstream in the direction of rotation of the rotating 
body, charge from the charger remains and the machine is left in such 
condition. Such residual charge remain as memory on the rotating body and 
may produce mottle on the first sheet at the time of resumption of 
copying. 
Further, in the past, when stopping the operation of an apparatus on 
detection of jamming of a sheet, a mechanical lock was applied so as to 
prevent operation of the apparatus till completion of elimination of 
jamming and therefore, unlocking of such lock was troublesome and the 
device for such unlocking was quite expensive. 
In addition, elimination of jamming was carried out by opening the casing 
of the apparatus, but even if the casing was not closed completely after 
elimination of jamming, the apparatus happened to restart running in some 
cases, bringing about quite a dangerous condition. 
On the other hand, it has hitherto been known, in a copying apparatus 
equipped with copying setting switches such as number of copy sheets 
setting key switch, copy start switch and copy stop key switch, etc., to 
provide segment indicators and lamps, etc. to let the operator know that 
various key switches were pressed and the signals accepted by the control 
unit provided in the inside. Further, it is already known to employ 
indication means such as lamps and light emission diodes, etc. for the 
purpose of alarm at the time of failure such as jamming at a copying 
apparatus. However, these two systems, if employed in a copying apparatus, 
caused an increase of costs or made the control and indication units of a 
copying apparatus complicated. Moreover, it often took time to judge the 
contents of indication, resulting in a loss of copying time. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide an image forming apparatus that 
has eliminated the abovementioned disadvantages. 
Another object of this invention is to provide a transfer type of image 
forming apparatus with a rotating photosensitive body properly processed 
so as to obtain a satisfactory image starting from the first sheet. 
A further object of this invention is to provide a transfer type of image 
forming apparatus in which latent image mottles on the rotating 
photosensitive body are minimized. 
Another object of this invention is to provide sequence control capable of 
preventing temperature rise at and around the light source in a transfer 
type of image forming apparatus in which light is radiated to the rotating 
photosensitive body in using a strong light source. 
Another object of this invention is to provide improvements and sequence 
control of a transfer type of image forming apparatus in which various 
processes are handled using a common light source. 
Another object of this invention is to provide an image forming apparatus 
to determine an optimum pretreatment time of the rotating body by 
rationally combining the standby time being indispensable until various 
conditions to make copying possible are set up with the time required for 
the sensitive element sensitivity equalizing process or the cleaning 
process. 
Another object of this invention is to provide a transfer type of image 
forming apparatus in which after machine stop due to transfer paper 
jamming or other malfunction, a high quality image can be obtained from 
the beginning. 
Another object of this invention is to provide an image forming apparatus 
in which after machine stop due to jamming or other malfunction, 
resumption of image formation is made possible by simple means. 
Another object of this invention is to provide an image forming apparatus 
in which safety relative to opening and closing of the casing has been 
elevated greatly. 
Another object of this invention is to provide an image forming apparatus 
in which the malfunction indication unit, etc. is simplified and yet the 
contents of control and alarm can be transmitted to the operator promptly 
and simply. 
Another object of this invention consists in an improvement of a compact 
copying apparatus employing an optical system for image exposure such as 
fiber array and so on. 
The above and other objects of this invention are clear from the following 
preferred embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiments of the present invention will hereinafter be described with 
reference to the drawings. Referring to FIG. 1 which is a cross-sectional 
view of the copying apparatus according to the present invention, the 
copying apparatus includes a reciprocable platen 1 for supporting an 
original thereon, a rotatable drum 2 having a seamless photosensitive 
medium on the periphery thereof, a lamp 3 for exposing the drum 2 to the 
original image on the platen 1, a corona charger 5 for precharging the 
surface of the photosensitive medium to the positive polarity, a corona 
charger 6 for discharging the surface of the photosensitive medium to the 
negative polarity with the exposure image, a developing device 8 for 
developing an electrostatic latent image, a charger 90 for transferring 
the developed image to transfer paper, a cassette 10 containing a number 
of sheets of transfer paper therein and removably mounted on the apparatus 
body, a bed 12 for manually supplying transfer paper, a roller 13 for 
feeding the transfer paper from the cassette, a pair of rollers 14 for 
feeding the transfer paper from the manual supply bed 12, microswitches 15 
and 16 for detecting the manually supplied transfer paper, a pair of 
register rollers 17 for registering the leading end of the transfer paper 
to the leading end of the image on the drum, a roller 18 for separating 
the transfer paper from the drum, a belt 19 for conveying the transfer 
paper, fixing rollers 201, 202 rollers 21 for discharging the transfer 
paper into a tray 22, a blade cleaner 23 for removing any remaining toner 
from the drum, a magnet roller 4 for collecting the toner removed by the 
blade 23, a container 7 for containing the toner collected by the roller 
4, a minus corona charger 24 for removing any remaining charge on the 
drum, a shutter 25 for imparting the light from the exposure lamp 3 
directly to the exposured surface of the drum for a predetermined time, 
mirrors 26 and 28 for imparting the light from the lamp 3 directly to the 
surface of the drum, and a cellfock lens 27 for causing the light of the 
lamp 3 reflected from the original to be imaged on the surface of the 
drum. 
Operation will now be described. When a main switch is closed, a motor for 
driving the drum 2 is energized and the lamp 3 is turned and the shutter 
25 is opened while, at the same time, the corona charger 6 is energized 
and the drum 2 is rotated. Thereby, the drum surface is precleaned to 
remove any remaining toner and charge and memory therefrom. When the 
fixing rollers 201, 202 is heated to the fixing temperature by an internal 
heater, a copy signal is generated. Where a copy switch is not closed or 
where a sheet is not manually inserted, the drum still continues to rotate 
thereafter and, when a predetermined number of pulses from a rotary 
encoder provided in the drum driving system and adapted to generate n 
pulses for one full rotation of the drum are counted, the drum is stopped 
from rotating. The above-described drum rotation is referred to as the 
first pre-rotation. 
When the copy switch is closed or a sheet is manually inserted during the 
rotation or the stoppage of the drum, the shutter 25 is closed and the 
drum 2 makes substantially one full rotation (hereinafter referred to as 
the second pre-rotation), whereafter the platen 1 starts its forward 
movement and the original on the platen 1 begins to be slit-exposed. The 
drum is slit-exposed to the reflected image of the original through the 
cellfock lens. The photosensitive medium of the drum comprises, in 
succession from the surface thereof, an insulating layer, a 
photoconductive layer and an electrically conductive layer and when the 
surface charged by the charger 5 reaches an exposure surface, plus charge 
is removed by the minus charger 6 and the optical image. When that surface 
reaches an uniform exposure surface, an electrostatic latent image of high 
contrast is formed on the drum surface by the light from the mirror 26. 
The latent image is imparted with toner at the developing area and 
developed into a visible image. The visible image is transferred to 
transfer paper at the image transfer area by the plus potential of the 
image transfer charger. The transfer paper is one which has been fed there 
by the timing operation of the paper feed roller 13, and passes through 
the image transfer area at the same velocity as the peripheral velocity of 
the drum with the aid of the register rollers 17. After the image 
transfer, the transfer paper is separated from the drum by the roller 18 
and conveyed to the fixing rollers 201, 202 by the belt 19, whereby the 
image on the transfer paper is fixed, where after the transfer paper is 
discharged into the tray 22 by the roller 21. After completion of the 
image transfer, the drum surface is cleaned by the blade 23 and discharged 
by the charger 24 and the memory thereon is removed by the light from the 
lamp 3 through the mirror 28. 
Where continuous copying is effected from the same original, the platen 1 
repeats its reciprocal movement over a number of times set by the ten key 
of the apparatus operating portion. 
FIG. 2 shows a portion around the platen. The platen has a magnet thereon, 
and reed switches 30, 31, 32 and 33 adapted to be actuated by the passage 
of the magnet are disposed on the movement path of the platen. When the 
magnet actuates the reed switch 35, the platen is stopped at its initial 
position in the center of the body, and when the magnet actuates the reed 
switch 30, the platen is changed over to the rightward or forward movement 
for the exposure. The switch 31 is for feeding paper by the paper feed 
rollers 13 and 14, and the switch 32 is for feeding paper by the register 
rollers 17. In the case of continuous copying, when the first slit 
scanning is terminated and the platen is backwardly moved to actuate the 
switch 30, the platen again starts its forward movement and effects the 
second scanning. In this manner, a set number of copies are obtained. The 
lamp 3 and simultaneous charger 6 are turned on in synchronism with the 
rotation of the main motor, namely, the drum, and the primary charger 5 
and pre-charger 24 are turned on except during the postrotation cycle. The 
lamp 3 is controlled so as to emit a high intensity of light during the 
scanning movement of the platen. 
In the case of the manual supply copying, when a sheet is inserted from the 
bed 12, the detector 15 detects the sheet. Then, the feed rollers 14 are 
operated to introduce the sheet into the apparatus. However, the rollers 
14 are not operated for a predetermined time (about two seconds) after the 
detector 15 has detected the sheet. This time allowance is for preventing 
oblique insertion of the sheet or for correcting the sheet to assure 
straight movement or enabling the sheet to be replaced by another one. 
When that time has elapsed, the rollers 14 are operated and also the drum 
2 is rotated to carry out a process sequence similar to that in the case 
where the copy switch is closed. The drum 2 starts the second pre-rotation 
as soon as the detector 15 detects the sheet, whereby the copy starting 
time can be quickened. Also, when the sheet insertion is detected by the 
detector 15, the feeding of sheets from the cassette is stopped. In the 
manner described above, copying can be started simply by inserting a sheet 
without closing the copy switch of the operating portion, and the sheet is 
fed into the apparatus while maintaining an accurate sheet position, so 
that the toner image can be transferred to the sheet at a predetermined 
location thereof and jam of the sheet can be prevented. 
When the switch 16 detects that the trailing end of the sheet has passed 
this switch, the rollers 14 are stopped, thus becoming prepared for the 
insertion of the next sheet. 
Now, a plurality of such detectors 15 may be provided at a right angle to 
the direction of sheet feed. These are for detecting oblique movement of a 
sheet and the rollers 14 are not operated until both of the detectors 
detect a sheet. Also, design may be made such that the second operation of 
the rollers 14 takes place only when there are outputs both of the 
detectors 15 and 16, as shown in FIG. 13. Thereby, jam can be prevented. 
FIG. 3 is a plan view of the operating portion of the FIG. 1 copying 
apparatus. It includes a main switch 39, a copy start key switch 40, a 
stop key switch 41 for interrupting continuous copy, a ten key 42 for 
causing a number to be stored in a memory to set the number of continuous 
copies, a clear key 43 for clearing the number stored in the memory, a 
copy gradation setting lever 44, a 7-segment displayer 45 for the memory 
number, a wait lamp 46 adapted to be turned on for display until the 
fixing temperature, a lamp 47 for displaying the absence of the cassette 
and of sheets in the cassette, and a lamp 48 for displaying when the 
container 7 for collecting the used toner by the cleaner is filled with 
such toner. Designated by 49 is a displayer for displaying when a sheet 
jams. When a sheet is jamming, the clear key and the ten key are not 
operated, but during the waiting, these keys are operable. 
The segment displayer 45 displays a zero-suppressed 1, irrespective of the 
waiting, upon closing of the main switch 39, displays the set number minus 
1 upon termination of each copy, and again displays the set number upon 
completion of the set number of copies and thereafter, when 30 seconds 
elapses without the copying being started, it again displays 1. Thereby, 
one-sheet copying can be started without the number setting by the ten key 
and the re-start of the copying can be executed smoothly. 
The wait displayer 46 is turned on and off by the closing of the main 
switch 39, and is statically turned on when the temperature of the fixing 
rollers is not reduced below the fixing temperature, namely, when a short 
time has elapsed after the previous operator has opened the main switch 
39, but is turned on and off when the temperature of the fixing rollers is 
below the fixing temperature (wait). The wait displayer is turned on also 
when the waiting time has elapsed after the fixing rollers have risen to 
the fixing temperature. When the main switch is opened, both the 
turn-on-and-off and the turn-on condition are extinguished and the wait 
displayer displays the main switch off condition. Further, when the copy 
switch is closed after wait-up, turn-on-and-off operation having a longer 
turn-on-and-off interval than that during the waiting is effected until 
the mode shifts to the post-rotation mode. That is, a single wait 
displayer can display four conditions, namely, the closed main switch 
condition, the wait condition during which copying is impossible, the 
ready-to-copy condition, and the copy cycle and thus, the number of 
displayers can be saved and this contributes to reduced cost of the 
apparatus. 
An overflow displayer 48 detects and displays the overflow condition of the 
container 7 and also detects deficiency of toner in the developer 
container 33, whereupon it is statically turned on for display. In the 
former case, a lamp may be turned on and off and in the latter case, the 
lamp may be statically turned on. 
The paper absence displayer 47 may be turned on and off in case of the 
absence of paper, and may be statically turned on in case of the absence 
of the cassette. 
Also, when toner deficiency in a hopper 33 or the overflow of the 
collecting container 7 is detected and where the continuous copying for 
the number of sheets set by the ten key is being executed, the copying is 
continued until the set number of copies is completed and thereafter, 
re-start of the copying is prevented. Thus, the display for warning is 
effected, but it is prevented that the copying is immediately interrupted 
to make the series of copying operations stagnant and aggravate the 
substantial copying speed, because even if the toner is deficient or 
overflow takes place, neither the image will be suddenly aggravated nor 
the apparatus will be contaminated. When transfer paper jams, the 
operation of the apparatus is immediately stopped to secure the safety of 
the apparatus. For the stop key, paper absence and cassette absence 
signal, the operation of the apparatus is not immediately interrupted but 
the then process cycle is permitted to complete, where after the start of 
the subsequent cycle is prevented. 
With reference to FIG. 4 which is an operation time chart of the FIG. 1 
copying apparatus, the operation sequence of scanning and the operation 
timing will be described in detail. 
Before the copy switch 40 is closed, the platen 1 is positioned centrally 
of the body as shown in FIG. 1. When the copy switch 40 is closed, the 
pre-discharging charger 24, the lamp 3, the primary charger 5, the 
secondary charger 6, the image transfer charger 9 and the shutter 25 are 
energized, so that pre-corona, primary corona, secondary corona, image 
transfer corona, pre-discharging exposure, blanket exposure and uniform 
exposure are imparted to the photosensitive medium, which thus becomes 
ready to start copying. The lamp 3 is turned on with weak light. 
When said predetermined number of pulses are counted, namely, when the drum 
makes a predetermined rotation, the platen 1 begins to move from the 
position of FIG. 1 to the left, and thereafter when the drum has made 
substantially one full rotation, the switch 30 is closed and therefore, 
the platen is stopped, and then starts to move rightwardly for exposure. 
The lamp 3 is now turned on with intense light and the shutter is 
deenergized to stop the blanket exposure and effect the exposure. The 
blanket exposure is an exposure whereby, when image exposure is not taking 
place, light is applied to the image-exposed surface so as to prevent 
occurrence of irregularity in the potential on the photosensitive medium. 
Also, by changing over the lamp between the intense light and the weak 
light, various process exposures can be appropriately accomplished by a 
single lamp. 
After image exposure has been done over substantially one full and half 
rotation, the movement of the platen 1 is stopped and then the platen is 
moved to the left. The start of this movement is effected by counting said 
predetermined number of pulses, and the number set in the memory is set in 
a register for copy counter and 1 is subtracted from that number. As a 
result, the content of the register becomes 0 in the case of a single 
sheet copy and thus, the re-start of the subsequent copying cycle is 
prevented. During this rightward movement, the reed switch 31 of FIG. 2 is 
actuated to operate the paper feed roller 13 or 14 and the reed switch 32 
is actuated to operate the register roller 17, thereby feeding a sheet. 
Even if the reed switches 31 and 32 are actuated during the platen 
movement at the other time than exposure, the rollers 13, 14 and 17 will 
not be operated. 
When the platen 1 actuates the switch 35 in its initial position, it is 
stopped from moving. Then, the lamp 3 is controlled to its weak turn-on 
and the shutter is operated to start the blanket exposure by the weak 
turn-on of the lamp 3. Thereafter, the drum rotation is continued so that 
the photosensitive medium is electrically and mechanically cleaned and, 
after substantial one full rotation of the drum, and process load as shown 
in FIG. 4 is removed and the drum rotation is stopped. After this 
stoppage, the main switch on condition is continued. 
In the case of continuous copying, even if the switch 35 is closed, the 
platen 1 is not stopped but continues to move leftwardly and when it 
actuates the switch 30, rightward movement of the platen 1 is again 
started and turns on the lamp 3 with intense light and deenergizes the 
shutter, thus re-starting the image exposure. 
In the present embodiment, one cycle of exposure scanning is effected with 
the platen being changed twice in its direction of movement and therefore, 
as shown in FIG. 1, the platen can be set at the center during stoppage of 
the copying. Also, copies of a full size corresponding to the body size 
can be produced and this leads to compactness of the machine. Moreover, 
the control of the two changes in direction is effected by the platen 
position switches and pulse count timer and this eliminates the necessity 
of providing a complicated spring mechanism for changing the direction. 
Further, the reed switch 35 is provided with a plurality of functions 
which will later be described and thus, any cumbersomeness caused by the 
reed switch which would otherwise result from the compactness of the 
machine may be prevented. 
The time whereat the rightward movement for exposure should be stopped and 
the direction of movement should be changed is determined in accordance 
with the size of sheets in the cassette 10 and the size of the sheet 
manually supplied from the manual supply bed 12. 
Some of the foregoing and the following embodiments of the present 
invention are also applicable to copying apparatus which have a first 
mirror movable at a velocity of V and a second mirror movable at a 
velocity of 1/2V and in which exposure scanning is effected by reciprocal 
movement of these mirrors, and are also applicable to copying apparatus in 
which a roll of paper is cut into the length of the size original on the 
platen and the thus cut paper is automatically fed, or to copying 
apparatus in which the latent image on the drum is transferred to a sheet 
and such sheet is developed. The present invention is also applicable to 
copying apparatus in which copy image is directly formed on a sheet 
without the intermediary of a drum or to copying apparatus in which other 
data than an original document is printed on a sheet. 
FIG. 5 is a vertical cross-sectional view of the cassette portion and 
manual supply portion, and FIG. 6 is a plan view thereof. Designated by 
15-1 is a photo-interrupter constituting a manually supplied sheet 
detector 15, denoted by 15-2 is an actuator piece swingable upon insertion 
of a sheet, and designated by 50 and 51 are microswitches adapted to be 
actuated by a cam provided on the cassette when the cassette is mounted in 
the apparatus body. When both of the switches 50 and 51 are in OFF 
position, there is generated a signal meaning the absence of a cassette; 
when the switches 50 and 51 are in ON and OFF positions, respectively, 
there is generated a signal meaning the presence of a cassette having 
sheets of the half-size, namely, A4 or B5 size; when the switches 50 and 
51 are in OFF and ON positions, respectively, there is generated a signal 
meaning the presence of a cassette having sheets of B4 size; and when both 
of the switches are in ON position, there is generated a signal meaning 
the presence of a cassette having sheets of the full-size, namely, A3 or 
B4 size. The three different signals for these sizes are used to determine 
the exposure stroke of the platen 1. 
With regard to manually supplied sheets, the full-size includes B4 size and 
so, the two sizes, i.e. the half-size and the full-size are detected by 
the sheet detector 15. 
Accordingly, where sheets are continuously fed from the cassette to execute 
the production of multiple copies, the copying cycle is repeated at a 
stroke corresponding to each size, namely, in a minimum time, whereby the 
time required for the copying can be reduced. This, coupled with the 
aforementioned effect of making sheet pick-up for the next sequence prior 
to the completion of the present sequence to thereby reduce the copying 
interval, provides an excellent merit. However, in the case of manual 
sheet supply, it is rare that sheets are continuously fed and therefore, 
two series of stroke controls suffice and this leads to simplification of 
the control circuit and reduced malfunctioning related to the size 
detection. 
The actuator piece of the sheet detector 15 is provided at the left end, as 
is shown in FIG. 6. This position corresponds to a belt provided outside 
of the image formation area of the drum to separate transfer paper from 
the drum after image transfer. This enables judgement as to whether or not 
a manually supplied sheet has been inserted into a separable predetermined 
position. 
The sheet detector 16 is provided at the same left end position as the 
sheet detector 15 with respect to the photosenstitive medium. This 
detector 16 has the following three functions. A first function is to 
detect the size of a manually supplied sheet and when the detector 16 does 
not detect a sheet at a predetermined time, the size of the sheet is 
judged as the half-size and when the detector 16 detects a sheet at the 
predetermined time, the size of the sheet is judged as the full-size. A 
second function is to render the length of the path from the leading end 
of a manually supplied sheet to the register rollers equal to the length 
of the path from the cassette sheet. Also, where the path to the register 
rollers is relatively long, the flexure of the sheet formed by the sheet 
striking against the register rollers is not always constant so that the 
image transfer registration is sometimes unstable. This can be prevented. 
That is, when the detector 16 detects a sheet fed by the manual supply 
rollers 14, these rollers 14 are deactivated after a predetermined time 
and wait while becoming prepared to feed the sheet to the register 
rollers. The rollers 14 are again operated by the signal from the reed 
switch 31 and begin to feed the sheet to the register rollers. A third 
function is to stop the rollers 14 when the detector 16 detects the 
trailing end of the sheet, and to become prepared for the next sheet. 
The operation of the sheet detector 15 detecting a sheet to operate the 
rollers 14 and of the sheet detector 16 detecting that sheet to deactivate 
the rollers 14, namely, the preparatory feeding and waiting, is for 
preventing the function of the register rollers from being damaged and 
more particularly, for ensuring the mountain of the loop (flexure) of the 
sheet formed by the sheet striking against the stopped register rollers to 
be kept down to a suitable range. Accordingly, there is no possibility of 
sheets being broken or jamming. Moreover, this is accomplished by a single 
roller, which leads to ease and lower cost with which the machine is made 
compact. 
This also holds true with the paper feed from the cassette. That is, the 
paper feed roller 13 is operated for a little time by the closing of the 
copy switch to pull out a sheet from the cassette, and then the feed 
roller 13 waits. The reed switch 31 starts to feed the so pulled out sheet 
until the sheet reaches the register rollers. 
FIG. 5 shows the form of a sheet near the register rollers 17. The cassette 
roller 13 is of a semicircular cross-section and makes a half rotation to 
effect preparatory feeding, and makes a further half rotation to effect 
main feeding. 
The present embodiment, as described above, is an image transfer type 
copying apparatus which is constructed by using the image scanning system 
provided by the reciprocal movement of the seamless photosensitive drum 2 
and the platen 1 and the image exposure system for the drum provided by 
the cellfock lens 27, namely, the one-to-one magnification bar lens and in 
which the construction is improved for the purposes of further 
compactness, higher performance and lower post. That is, the copying 
apparatus of the present embodiment has been made compact with the copy 
interval reduced and with the image transfer registration maintained well 
by the control for the change-over of the optical path by using a single 
lamp for various exposures, the sheet feed control for preventing an 
increase in number of timing rollers resulting from the sheet path, and 
the smooth control of changes in direction of the platen by low-cost 
means. Moreover, in the constuction of the present embodiment, the copy 
size is not fixed, two series of feed paths are provided so as not to 
restrict the types of copy sheet, malfunctioning is eliminated and sheet 
jam can be prevented to the utmost. If the cellfock lens 27 is provided in 
a space forming the shortest distance between the drum 2 and the platen 1, 
as shown in FIG. 1, it will be very effective to make the apparatus 
compact. 
(Controller) 
FIGS. 7A, 7B and 7C are diagrams of the operation control circuit of the 
FIG. 1 copying apparatus. Q.sub.1 -Q.sub.6 designate flip-flops for 
operatively controlling a main motor (which operates the drum 2, various 
rollers and the belt 19), a clutch for operating the manual supply rollers 
14, a clutch for operating the register rollers 17, a clutch for operating 
the cassette roller 13, a clutch for backwardly moving the platen 1, and a 
clutch for forwardly moving the platen 1, and a clutch for forwardly 
moving the platen 1. The flip-flops Q.sub.1 -Q.sub.6 are switched on by a 
pulse rising signal to a port S, and switched off by a pulse rising signal 
to a port R. Q.sub.7 designates a one-shot for effecting the wait control 
of the main motor and it generates an output of time limit T.sub.3 as 
shown in FIGS. 8A-8C after the closing of the main switch. Q.sub.8 
designates a flip-flop for judging the manual supply mode and the 
functions of the ports S and R thereof are identical to those of the 
flip-flop Q.sub.1 except that it is not an edge trigger. Q.sub.9 denotes a 
timer for operating the manual supply rollers 14 and generating an output 
after a time limit T.sub.1 as shown in FIG. 9, and it is operable on 
condition that an input signal shall be ON for the time T.sub.1. That is, 
the timer Q.sub.9 can complete its timer operation as long as there is an 
input signal, and cancels its timer operation when the input signal 
disappears. Q.sub.10 -Q.sub.13 denote counters for counting clock pulses 
generated by the drum rotation from the point of time whereat the input 
signal has been entered and for generating a pulse output when the count 
reaches a predetermined count number. The counters Q.sub.10 and Q.sub.11 
are for determining the deactivation of the manual supply rollers and of 
the cassette roller, and the counters Q.sub.12 and Q.sub.13 are for 
determining the number of pre-rotations and the number of post-rotations. 
N (a predetermined number) clock pulses DCK are generated at equal 
intervals per full rotation of the drum by the aforementioned rotary 
encoder. Q.sub.14 is a counter similar to the counters Q.sub.10 -Q.sub.13, 
but in the case of the cassette mode, it selects a preset number in 
accordance with the size of the cassette and in case of the manual supply 
mode, it selects a preset number in accordance with the size of a manually 
supplied sheet in a mode different from the cassette mode. The counter 
Q.sub.14 is for controlling the stroke of the platen. G.sub.1 -G.sub.10 
designate AND gates, G.sub.13 -G.sub.23 denote OR gates, and INV.sub.1 
-INV.sub.6 designate inverters. 
Signals M.sub.1, MRCl, RGCl, CRCl, FWCl and BWCl are the signals for 
operating the main motor, the manual supply roller, the register rollers, 
the cassette roller, the forward movement of the platen and the backward 
movement of the platen when these signals are 1, and for deactivating 
these members when the signals are 0; CLK is a clock pulse; BP is a signal 
for reversing the platen; and END is a copy cycle interrupting signal 
provided by signals STB, CTU, PEP and CEP for the stop key, count up, and 
paper/cassette absence. "Manual Supply" is a signal indicative of the 
manual supply mode; JAM is a signal indicative of sheet jam and generated 
upon detection of jam; CTU is a count-up signal of the copy counter 
indicative of a preset number of copies having been completed; and SW is a 
main switch on signal put out upon detection of the condition of the 
switch SW. PS.sub.1 and PS.sub.2 are signals put out when a manually 
supplied sheet is detected by the detectors 15 and 16; PF and RG are a 
paper feed signal and a registration signal generated when the platen has 
actuated the reed switches 31 and 32 as aforementioned; CPB and STB are 
signals generated when the copy button and stop key of the operating 
portion are operated; and SP and HP are signals generated when the platen 
has actuated the read switches 30 and 35 and indicative of the plate 
forward movement start position and stop position. PEP is a signal put out 
when the emptiness of the cassette 10 has been optically detected by a 
lamp 60-1 and a light-receiving member 60-2, and CEP is a signal 
indicative of removal of the cassette 10 and put out by microswitches 50 
and 51 operatively controlled by the cassette ON. TEP is a signal 
indicative of the absence of toner in the developing device 34 and put out 
when it is detected by a toner level detector 61 in the developing device 
that the level of the toner has lowered below a predetermined level, and 
OVF is a signal indicative of the overflow condition of the collected 
toner in the collecting container 7 and put out when the overflow is 
detected by a level detector 62. WAIT is a signal indicative of the wait 
condition and put out by a thermistor Th which detects the temperature of 
the fixing roller. 
Operation will now be described. During the duration of the wait signal 
WAIT generated upon closing of the main switch 39, the one-shot Q.sub.7 of 
FIG. 7B is operated and a main motor signal M.sub.1 is put out through the 
gate G.sub.26 for a time T.sub.3 to effect a first pre-rotation of the 
drum. Thereafter, if the copy button is depressed when the wait is up 
(WAIT is 0) and standby has come, the flip-flop Q.sub.1 is set and 
likewise the main motor is energized to start the process. 
(Cassette Mode) 
Now no sheet is being inserted from the manual supply bed 12 and therefore, 
the detector 15 is OFF and accordingly, the flip-flop Q.sub.8 is OFF and 
consequently, a manual supply signal is not put out and accordingly, the 
gate G.sub.1 is OFF-controlled and the flip-flop Q.sub.2 is not set and 
thus, the manual supply rollers 14 are not operated. 
Assuming that paper is absent and toner is absent and no overflow is 
occurring, start signal is entered into the gate G.sub.2 through the gates 
G.sub.3, G.sub.25 and G.sub.16 upon depression of the copy key. Since wait 
and manual supply reversing signals (all being 1) are applied to the other 
port of the gate G.sub.2, the flip-flop Q.sub.4 is set on and the clutch 
of the cassette roller 13 is engaged. While the counter Q.sub.11 is 
effecting a predetermined pulse count through the gate 17, the roller 13 
makes a half rotation and stops, thereby pulling out substantially one 
half of a sheet from the cassette and stopping the sheet. By this, the 
difference between the time from the copy start till image transfer and 
the time required for the movement of the sheet, which difference would 
occur where the drum is small, can be corrected. 
Upon the output of this flip-flop Q.sub.4, the count CLK of clock pulses is 
started by the counter Q.sub.12 through the gate G.sub.22. A predetermined 
number of pulses counted corresponds substantially to one full rotation of 
the drum, and the flip-flop Q.sub.5 is set through the OR gate G.sub.24 to 
put out signal FWCl, which moves the platen leftwardly. When the platen 
actuates the reed switch 30, the flip-flop Q.sub.5 is reset through the 
gate G.sub.19 to disengage the clutch FWCl while the flip-flop Q.sub.6 is 
set to put out clutch signal BWCl, which moves the platen rightwardly. The 
image exposure lamp 3 is turned on and controlled in synchronism with the 
main motor M.sub.1, and the quantity of light thereof is controlled in 
synchronism with the control of this BWCl so that the light is intense 
when BWCl is ON. The reset time of the flip-flop Q.sub.6 for terminating 
the first slit exposure is determined by cassette switches 50 and 51. 
That is, when the switches 50 and 51 are 1 and 0, respectively, sheets of 
size A4 are contained in the cassette and therefore, the exposure stroke 
is terminated at that width. That is, the preset number of the counter 
Q.sub.14 which counts clock pulses and determines the reversing position 
is determined to n1 which is suited for A4. In case of size B4, the 
switches 50 and 51 are 0 and 1, respectively, and therefore, n2 greater 
than n1 is preset. In case of size A3, the switches 50 and 51 are 1 and 1 
and therefore, n3 which is greater than n2 is set. When the switches 50 
and 51 are 0 and 0, cassette absence signal CEP is put out through the 
gate Q.sub.5. 
The counter Q.sub.14 effects pulse count after the register switch 32 has 
been closed and, when the count reaches the aforementioned number n1-n3, 
the counter puts out BP to reset Q.sub.6 and terminate the forward 
movement. On the other hand, Q.sub.5 is set by BP through the gate 
G.sub.24 to move the platen leftwardly and, when the platen actuates the 
reed switch 35, Q.sub.5 is reset to stop the backward movement. 
Now, when the switch 31 is closed in the course of the forward movement of 
the platen, signal PF is applied to the gates G.sub.1, G.sub.2 and counter 
Q.sub.11 through the gates G.sub.15, G.sub.16 and G.sub.17. Since the gate 
G.sub.1 is OFF as aforementioned, Q.sub.2 is not set, but by the opening 
of the gate G.sub.2, the paper feed flip-flop Q.sub.4 is again set and the 
roller 13 is further rotated to further pull out the previously pulled out 
sheet. Then, the leading end of the sheet strikes against the register 
roller 17 to thereby from a loop (slack) in the sheet. Thus, the sheet can 
be stopped by the register rollers with an appropriate amount of loop 
maintained in the sheet, thus eliminating the necessity of intricately 
taking into account the interval between the paper feed roller and the 
register rollers and also eliminating the necessity of providing any 
special means in the path, which contributes to compactness of the 
machine. Also, the loop can be made appropriate and constant and this can 
reduce jam of sheets as well as ensure stable and accurate registration 
between the drum image and the sheet to be accomplished by the register 
rollers 17. Such contrivance is also made in the case of manual supply (as 
will later be described). 
Thereafter, by the closing of the register switch 32, the flip-flop Q.sub.3 
is energized to operate the rollers 17. The rollers 17 continue to rotate 
until the start switch 30 is closed next time. 
In the case of a preset number of multi-copies, the gate G.sub.10 is not 
opened even when one cycle of the process has been terminated and 
therefore, Q.sub.3 is not reset even when the stop switch 35 is closed and 
accordingly, the backward movement is continued until Q.sub.5 is reset by 
closing of the start switch 30, whereupon the backward movement is 
stopped. At the same time, Q.sub.6 is again set to start the second 
forward movement exposure. The gate G.sub.10 is open by an END signal 
provided by each of the signal STB from the stop key 41, paper absence and 
cassette absence signals PEP and CEP and a signal CTU indicative of a 
preset number of copies having been completed. Accordingly, the gate 
G.sub.10 controls the outputting of signal HP so that scanning is repeated 
until a preset number of copy cycles is completed and until an 
interruption instruction is put out from the stop key or due to paper 
absence. Also, Q.sub.4 is set by signal HP through the gates G.sub.4, 
G.sub.25, G.sub.16 and G.sub.2 to feed the second and subsequent sheets. 
Where only one copy is desired, CTU is being put out and therefore, 
Q.sub.4 is not set even if this signal HP is detected. Also, even when the 
platen starts to move upon depression of the copy button and actuates the 
switch 35, Q.sub.4 is likewise not set. 
(Manual Supply Mode) 
The manual supply mode will not be described in detail. The operator places 
a sheet on the bed 12 and urges it toward the rollers 14. First, the 
detector 15 judges whether or not the sheet has been appropriately 
inserted. When signal PS.sub.1 is generated, timer Q.sub.9 is energized to 
start T.sub.1 time limiting operation. Before this T.sub.1, the direction 
of the sheet is corrected and the sheet is caused to strike against the 
stopped rollers 14 so that the sheet is substantially at a right angle to 
the rollers 14. That is, for some time after the sheet has been inserted, 
the attitude of the sheet can be corrected to prevent jam thereof which 
would otherwise occur due to oblique movement of the sheet after it is 
fed. 
When the time T.sub.1 has elapsed, the flip-flop Q.sub.2 is set through the 
gates G.sub.15 and G.sub.1. Also, the flip-flop Q.sub.1 is set through the 
gate G.sub.27. The manual supply input to G.sub.3 is 1, since the 
flip-flop Q.sub.8 is set by the switch 15. Also, since the gate G.sub.2 is 
inhibited through an inverter, the driving of the cassette roller 13 is 
prevented even if signal PF is generated. The drum is rotated by Q.sub.1 
and the manual supply rollers 14 are rotated by Q.sub.2 to introduce the 
sheet into the apparatus. The sheet arrives at the detector 16 provided 
behind the rollers 14. Then, the detector generates signal PS.sub.2 and 
the counter Q.sub.10 starts counting. When the time set by the timer 
T.sub.2 has elapsed and the count is up, Q.sub.2 is reset through the gate 
G.sub.23 to stop the rollers 14, which thus wait for the next paper feed 
step. This corresponds to the preparatory paper feed from the cassette in 
the cassette mode, wherein the preparatory paper feed takes place as 
aforementioned when the detector 15 detects a manually supplied sheet 
irrespective of the forward or backward movement of the platen 1. 
Also, upon operation of the rollers 14, the prerotation counter Q.sub.12 is 
started through the gate G.sub.22 and after a predetermined rotation, the 
flip-flop Q.sub.5 is set to move the platen leftwardly in the same manner 
as in the case of the cassette mode and, when the platen strikes against 
the start switch 30, the forward movement for exposure is started. 
Thus, in the manual supply mode, a copy cycle can be entered without 
closing the copy switch 40, thereby facilitating the operation. 
When the switch 31 is closed during the forward movement for exposure, 
Q.sub.2 is again set through the gates G.sub.15 and G.sub.1 to drive the 
rollers 14, which thus feeds the sheet to cause it to strike against the 
register rollers. When the next switch 32 is closed, Q.sub.3 is set in the 
same manner as in the case of the cassette mode, to rotate the register 
rollers 17, which thus feed the sheet to the image transfer station. 
When the sheet leaves the detector 16, Q.sub.2 is reset through an inverter 
and gate G.sub.23 to stop the manual supply roller 14 from rotating. This 
is for the preparation for the feeding of the next sheet. 
In the case of the manual supply mode, copying can be started or re-started 
even if there are generated paper absence, toner absence and overflow 
signals. In the manual supply mode, several sheets of copies at most are 
to be produced continuously and thus, even if 1 of TEP and OVF is 
generated, it will not adversely affect the image or the apparatus. 
Consequently, this technique sets a value on the simplicity of operation. 
However, it is possible to effect such a control that when TEP and OVF are 
1, start of the copying (the first sheet) is permitted but the subsequent 
re-start is prevented or the copying is quite impossible from the first. 
Even if the sheet is momentarily spaced apart from the detector 15 during 
the time T.sub.1 set by the timer Q.sub.9, the timer operation can 
continue and thereby prevent oblique movement of the sheet to the utmost. 
The detectors 15 and 16 are disposed so as to be concerned with separation 
of sheets and can therefore serve also to position the sheets, and even 
small sheets such as postcards or the like can be copied at an appropriate 
position. 
Detailed description will now be made of the control of the reversing of 
the platen in the case of manual supply. In FIG. 7A, the signal PS.sub.2 
of the sheet detector 16 and a predetermined count number signal x from 
the counter Q.sub.14 are applied to the input of G.sub.6. This is for 
selecting one of the preset numbers n1 and n3 of the counter Q.sub.14. 
That is, the counter Q.sub.14 judges the size of a sheet as the large size 
(full) such as A3 or B4 when a sheet is present at the rear counter 16 for 
a predetermined number of pulses after the count has been started from the 
registration signal RG, and judges the size of a sheet as the small size 
(half) such as A4 when a sheet is not present, thereby bisecting the scan 
stroke. That is, when x is 1 and if 1 is applied to the gate G.sub.6 
through 0 of PS2, namely, through an inverter, n1 is preset in Q.sub.14. 
If the detector 16 is still detecting a sheet when x is 1, 0 is applied to 
G.sub.6 and n3 is preset through an inverter and gate. Accordingly, in the 
case of manual supply, the counter continues counting till n.sub.3 or 
n.sub.1 after x in accordance with the full-size or the half-size, thus 
putting out a reversing signal BP. Also, if manual supply again takes 
place during the backward movement, the output of the inverter INV2 will 
become 0 and so, G.sub.10 will stop putting out its output and 
consequently, the switch 35 will not stop the platen but the cycle will 
continue. 
What is important here is that since the sheet has already been fed to the 
register rollers 17, the timing signal x which senses the sheet detector 
16 is a pulse number smaller than n.sub.1 of A.sub.4 size and also is a 
timing generated before completion of the stroke corresponding to A.sub.4 
size. 
In this manner, the size data of manually supplied sheets can be 
sequentially judged at the interval between the process sequence controls 
without such data being applied in advance in any manner and this can 
contribute to the sequence control and simplify the circuit arrangement. 
In the case of the cassette mode or in the case of the continuous multicopy 
operation, it is desired to increase the speed to the utmost and to set 
strokes corresponding to various copy sizes and therefore, three different 
presets are effected as shown, whereas in the case of the manual supply 
mode, the desired number of copies is several sheets at most and 
therefore, two different stroke modes suffice. In this manner, the control 
mode in the case of the manual supply is simplified as much as possible to 
reduce the trouble to the utmost. 
Description will now be made of the copy interruption instruction in the 
cassette mode. Re-start by the copy key is prevented by PEP, TEP, CEP and 
OVF. Before completion of the multicopy operation, the gate G.sub.18 puts 
out a signal END by stop key STB signal and PEP and LEP signals to inhibit 
the gate G.sub.14 and prevent the subsequent preparatory operation of the 
paper feed roller 13. Accordingly, the multicopy operation is interrupted. 
In the case of the stop key, copying is re-started with the copy key ON. 
By TEP and OVF, the multicopy operation is not interrupted but is 
completed. 
It is also possible to divide the sense timing of the detector 16 in the 
manual supply mode into x.sub.l . . . x.sub.n and effect the sense to 
thereby effect various stroke controls and it is also possible to set a 
preset number different from that in the cassette mode in Q.sub.14. 
When a sheet from the cassette or a manually supplied sheet has jammed, jam 
signal JAM is applied to the R ports of Q.sub.1 -Q.sub.6 and Q.sub.8 to 
deenergize all the clutches and the main motor without waiting for the 
completion of the process. 
The flip-flop Q.sub.8 for setting the manual supply mode is reset by the 
reversing signal BP or the jam signal JAM. Also, during the time that the 
platen moves backwardly after completion of the exposure, manual supply or 
sheet pick-up from the cassette by the copy key 40 can be effected to 
enable quick re-start of the copying. By causing the timer Q.sub.9 to be 
started by the AND of the inverter toner absence signal from G.sub.21 and 
the detection signal PS.sub.1, the manual supply copying can be prevented 
when OVF and TEP are 1. 
As described above, when the manual supply copying is started, the setting 
of Q.sub.4 which drives the cassette roller 13 is inhibited by the set 
output of Q.sub.8, so that the cassette mode is not entered even if the 
copy key 40 is depressed. However, when the manual supply mode exposure is 
terminated, Q.sub.8 is reset by BP signal and thus, the inhibition of 
Q.sub.4 is released. Accordingly, sheet pick-up from the cassette can be 
effected by the copy key 40 before the platen comes to its rest position. 
Consequently, mode change-over can be achieved a little early. 
Also, when a manually supplied sheet is inserted while copying is being 
repeatedly executed in the cassette mode, the setting of Q.sub.4 is 
inhibited and Q.sub.2 is set, so that the cassette mode copying is 
interrupted and the manual supply copying is carried out preferentially. 
If the copy key 40 is again depressed after termination of the manual 
supply copying, the remaining number of copies will be completed. 
During the time that copying is being repeated in the cassette mode, it is 
also possible to inhibit manual supply until the BP signal for the last 
copy is generated and this can be accomplished by applying another CTU 
signal to the gate G.sub.2. 
FIG. 10 shows an example of the circuit for displaying toner absence and 
overflow. Designated by Q.sub.50 -Q.sub.52 are operational amplifiers for 
detecting toner absence, overflow and paper absence, respectively. These 
operational amplifiers put out their outputs by comparing their detection 
results with a standard voltage V.sub.s. An element 61 judges the toner 
level in the developer container from the presence or absence of toner 
intervening between a lamp and a light-receiving member (CdS), and puts 
out TEP when the quantity of light received exceeds a predetermined level. 
An element 62 uses a lamp and a light-receiving member and detects toner 
in the same manner as the element 61 and puts out OVF when the quantity of 
light received is below the predetermined level. An element 60 puts out 
PEP in the same manner as the element 61 when the quantity of light 
received exceeds the predetermined level. G.sub.60 -G.sub.62 designate OR 
gates, G.sub.65 denotes an AND gate, and INV 20-21 designate inverters. 
CPU.sub.1 controls the start, stop and movement of a control unit 
CPU.sub.2 which applies the signals of the ten key, stop key, copy key and 
clear key of the operating portion, effects the display operation of the 
displayer 45, causes the copy present number by the ten key to be stored 
in a register RST (memory) and controls the process sequence. 
Operation will now be described. When the toner in the developing device 
becomes decreased during the copying, signal TEP is put out from the 
operational amplifier Q.sub.50. That signal is applied through the gate 
G.sub.61 to the toner absence displayer 48, which is thus turned on to 
give a warning. At the same time, that signal OFF-controls the gate 
G.sub.65 through an inverter. Accordingly, even if an attempt is made to 
re-start the copying by depressing the copy key after the termination of 
the copying, the copying cannot be re-started because STAT signal if OFF. 
However, the stop signal STB is not being controlled by TEP so that the 
preset number of copies set by the ten key can all be completed even if 
the lamp 48 is turned on in the course of the copying. 
When the toner in the toner collecting container 7 is increased 
approximately to an overflow condition, signal OVF is put out and like 
TEP, it controls the starting gate G.sub.65 through the gate G.sub.61. At 
the same time, this is displayed by a displayer which is originally 
adapted to display toner absence. In this case, the displayer may be 
caused to effect a display different from TEP which effects 
turn-on-and-off display. Again in the case of OVF, STB is not controlled 
but the preset number of copies are completed. The completion of the 
preset number of copies is accomplished by counting the signal BP (the 
reversed position of the platen) for each copy cycle by the preset number 
stored in the register RST and putting out the signal END. The copy 
interruption is such that by the stop key ON and jam, signal STB is put 
out and one process cycle during the stop key ON is terminated, where 
after the continuation of the next cycle is prevented, and not all of the 
preset cycle is executed. 
Such prevention is effected during cassette absence or paper absence. That 
is, by the paper absence signal PEP and cassette absence signal CEP, 
signal STB is put out to CPU.sub.2 through the gates G.sub.62 and 
G.sub.60. Thereby, a treatment similar to that in case of the stop key ON 
is carried out. Also, PEP and CEP cause the same displayer 47 to display 
that effect. Alternatively, the display contents may be distinguished from 
each other by causing one to be turned on and off at a predetermined 
period and causing the other to be statically turned on. 
When sheet jam has been detected, signal JAM is put out to turn on or turn 
on and off the displayer 29. At the same time, the power sources for 
dangerous load (high voltage, heater, etc.) are switched off. That is, the 
process cycle is interrupted in the course thereof so that copying for the 
preset cycle as well as for one cycle may not take place. However, the 
power source of CPU and RST can be held so that the preset number is not 
cancelled even if the main switch 39 is opened. In the case of such jam, 
the next process re-start can be accomplished by manually closing a switch 
which releases the jam and cannot be accomplished simply by depressing the 
copy key. 
In addition, it is possible to put the end signal and the output of sensor 
61 or 62 into an and-gate, and put the output thereof into one of the 
operation amplifiers Q.sub.50 and Q.sub.51. By doing so, the toner absence 
and the overflow can be detected only after the termination of the preset 
number of copies, and then it is displayed and the resuming operation is 
stopped. 
In this case, the lamp of sensor 61 or 62 can be controlled by the end 
signal. Additionally, by controlling the WAIT signal with END signal, the 
display and the resuming operation can be controlled. The method explained 
in this paragraph is very effective when the sequence, display and 
resuming operations are all controlled by a computer (e.g. when the 
circuits of FIG. 10 are all embodied by a computer). 
FIG. 11 is a diagram of an example of the circuit which puts out the wait 
signal WAIT. In FIG. 11, r.sub.1 -r.sub.3 designate resistors which, with 
a thermistor Th, constitute a temperature detecting bridge. Q30 designates 
an operational amplifier which puts out O when the temperature of the 
thermistor Th is below a predetermined temperature and puts out 1 when the 
temperature of the thermistor Th is above the predetermined temperature, 
namely, the fixing temperature. Q31 is a thyristor electrically energized 
by the output 1 of the operational amplifier. Q32 denotes a transistor 
adapted to be turned on by the output 1 of the operational amplifier to 
drive a relay K1 for electrically energizing a heater H. AC is an 
interchangeable power source, and Q35 and Q36 are NAND gates. Q38 
designates an AND gate for operatively controlling the wait display lamp 
46. Q39 denotes an AND gate which puts out a signal STAT for starting the 
copy process. INV10 and 11 are intervers. Q40 is a transistor for turning 
on the wait lamp 46. CPU is a copy sequence controller. COPY is a signal 
indicative of the copying cycle being executed and the time chart thereof 
is apparent in FIG. 4. OSC1 and OSC2 designate oscillators of different 
oscillation frequencies which become operative upon closing of the main 
switch. 
FIG. 12 diagrammatically shows an example of the power source circuit. It 
includes a fuse FS, a low voltage transformer LVT for obtaining 
controlling source voltages Vc and Vcc, a high voltage transformer HVT for 
operating the corona charger, a transformer MVT for operating a medium 
load such as a halogen lamp, a circuit CV for stabilizing the outputs Vc 
and Vcc, and a rectifier REC. 
Operation will now be described. When the main switch 39 is closed, DC 
voltages Vc and Vcc are put out to render the circuits of FIGS. 7, 11, 
etc., operative. When the temperature of the fixing roller is so low that 
copying is impossible, the operational amplifier puts out 0 due to the 
high resistance of the thermistor Th and the thyristor Q31 maintains its 
OFF condition and accordingly, the wait signal WAIT is put out by the 
voltage Vc. On the other hand, the transistor Q32 energizes the relay K1 
to heat the heater H1. Consequently, even if the copy key 40 is depressed, 
sheet feeding and scanning would be prevented from starting by the gate 
Q39, However, the gate Q35 is receiving as input the signal from the 
oscillator OSC1 and the copy signal COPY is applying 0 signal and 
therefore, a signal synchronized with OSC1 is put out to the gate Q38. 
Since a signal 1 provided by the 0 signal of COPY is being applied to the 
other input of the gate Q38, the transistor Q40 is turned on and off in 
synchronism with OSC1 and accordingly, the wait display lamp 46 is turned 
on and off in synchronism with the period of OSC1. This provides to the 
operator a warning that the copying is impossible. When the thermistor Th 
reaches the fixing temperature, the thyristor Q31 is energized by the 
output of the operational amplifier Q30 and thus, the signal WAIT becomes 
0. On the other hand, the relay K1 is deenergized to stop the power supply 
to the heater H. The output of the gate Q35 becomes 1 and accordingly, by 
the signal 1 of the gate Q38, the transistor Q40 is statically turned on 
to turn on the lamp 46. Since one input of the gate Q37 becomes 1, the 
reception of the copy key is rendered possible and thus, the apparatus 
waits in the so-called standly condition. In this case, even if the 
ON-OFF-control of the heater H is effected to maintain the fixing 
atmosphere at the fixing temperature, the signal WAIT remains to be 0 due 
to the power supply holding action of the thyristor and therefore, no 
display malfunctioning occurs. 
When the main switch 39 is closed during this standby, the voltages Vc and 
Vcc become OFF and therefore, in spite of the aforementioned holding 
action of the thyristor, the power supply to the wait display lamp 46 is 
cut off to turn off this lamp. Thus, this lamp 46 enables the operator 
also to judge the power supply condition to the apparatus. 
When the main switch 39 is again closed, the thyristor is immediately 
energized through the operational amplifier because the fixing roller, 
namely, the thermistor Th is not cold, and as aforementioned, the lamp 46 
is statically turned on to bring the machine into standby condition. 
When the copy key 40 is depressed during this standby, start signal is put 
out to CPU to start the operations of the main motor, paper feeding and 
scanning. CPU puts out copy signal COPY and therefore, the output of the 
gate Q35 is completely rendered to 1 and a series of pulses of the 
oscillator OSC2 are put out from the gate Q36. Accordingly, the gate Q38 
turns on and off the transistor Q40 in synchronism with OSC2 and 
consequently, the transistor can turn on and off the lamp 46 at a 
repetition period longer than that of OSC1. When the scans for a preset 
number of copies have been terminated and the platen arrives at its 
reversing position, the signal COPY becomes 0 and therefore, the standby 
condition is again brought about with the lamp 46 being statically turned 
on, and thus, the platen becomes ready to receive copy re-start 
instruction. 
When the copy key is depressed at this time, the same operation as for the 
previous preset number of copies is restarted without the number of copies 
being re-set. This re-start is effected in the same manner as the 
continuous copying wherein even when the platen is returned to its stop 
position, it is not stopped but is caused to continue to scan. 
If the main switch 39 is opened without the copying being re-started, the 
lap 46 will be turned off to display that the voltage to the loads such as 
clutch, main motor, corona charger, etc. has been cut off. 
It is also possible that after the main switch 39 has been opened, the 
amount of power supplied to the lamp 46 is decreased to display the OFF 
condition thereof. This will be effective for the case where the central 
control unit CPU remains alive even if the switch 39 is opened, namely, 
the case where it is desired to continue the memory's operating condition. 
Particularly, when jam of a sheet is to be dealt with, it is often the 
case that the main switch 39 is opened and in such case, it is not 
preferable to cancel the preset number stored in the memory and thus, 
using said display as the display of the memory ON condition would be very 
convenient. 
Now, in the time chart of FIG. 4, if, on the first sheet, the disconnection 
of thermistor 204 or overflow of cleaning toner or no toner, no cassette 
or no paper is detected, solid lines appear and if the conditions are 
normal, dotted lines appear. When the disconnection of the thermistor is 
detected, the signal WAIT is outputted. 
The fixing means consists of the upper roller 202 and the lower roller 201 
and a halogen heater 203 is inserted as a heat source in the upper roller, 
a temperature sensing element 204 is provided adjacent to the upper roller 
202 for detection of upper roller surface temperature and the temperature 
control of the fixing means 20 is effected on the basis of signals from 
the temperature sensing element 204 in such manner as to maintain constant 
the upper roller surface temperature by switching on and off the halogen 
heater 203. 
(First prerotation control) 
Next, the aforesaid first prerotation control will be described in detail. 
In FIG. 7B, the input signal S1 is a signal which changes from the status 0 
to 1 in time T.sub.1 after turning on the power switch 39 (hereinafter 
called "power ON signal"), while the input signal S2 is a signal which 
changes from the status 0 to 1 in time T.sub.2 after turning on the power 
switch 39 in case the aforementioned copying conditions are not ready 
(with T.sub.1 &lt;T.sub.2), which returns to 0 at the time when copying 
conditions are available (hereinafter called "wait status signal"). 
At Q202, power is applied between the terminals V+ and V- by the timer IC 
and if a signal trailing from 1 to 0 is inputted as a trigger signal to 
the trigger input terminal TR, it outputs 1 from the output terminal Q for 
the time corresponding the time constant to be determined by the resistor 
R 201 and the condenser C201 connected to the time constant terminal TC. 
In this case, however, if 0 signal is inputted to the reset terminal R, 
the signal 1 rises at the terminal Q even before time-up. The signal S3 to 
be outputted from the output terminal Q is the one to be inputted to other 
circuit (not shown) so as to execute the first prerotation in the status 
1, which will hereinafter be called "first prerotation control signal ROT 
1". 
Here the wait signal S2 remains in the status 1 (WAIT) until the fixing 
means 20 reaches the required sensitivity by the signal from the 
temperature sensing element 204 in the fixing means in FIG. 1. Here a 
signal during heater wait will be taken as an example, but it may be a 
developing solution concentration recovery signal or a signal during the 
time in which drum surface potential is detected and 0 or uniform 
specified potential can be detected. 
FIG. 8A represents a time chart in cases where the fixing roller 
temperature is relatively low at time of power switch ON. The WAIT signal 
S2 turns into 1 after time T2 (approx. 30 sec.) from power ON and, via the 
circuit comprising noise prevention resistor R202 and condenser C203, is 
inputted to the terminal R of Q202. Thereafter, after the lapse of time T1 
(approx. 50 sec.) from power ON, the power on signal S1 is inputted via 
the inverter Q201 to the terminal TR of Q202 as a 1-to-0 trailing signal. 
Accordingly, at this time the signal ROT1 is outputted as 1 from the 
output terminal Q and starts rotation of the drum 2 (FIG. 22). If wait 
condition continues even after T3, the first prerotation is carried out 
and the sensitive body equalizing process (cleaning, removal, 
pre-exposure, etc.) effected for the time T3 (equivalent to ten odd 
rotations of the drum) to be determined by R201 and C201 and the drum 
stops at T3. The time T3 is set at approx. 30 sec. as the time in which 
the sensitive element (5 to 15 cm in diameter) can be equalized in the 
aforementioned processes even when the machine is shut-down for a 
considerably long time after power switch OFF so as to avoid excessive 
rotation and equalization. 
FIG. 8B represents a time chart in cases where the fixing roller 
temperature is relatively high at the time of power ON. That is, it 
represents a case of relatively short-time shutdown after power switch OFF 
during pause of copying and stop of power supply to the heater 202. 
In this case, various conditions on the drum surface do not vary much. For 
instance, the sensitivity of the sensitive element does not recover much, 
remaining nearly in the previous condition. In this case, sometimes the 
wait signal S2 becomes 0 in time T4 shorter than the time T3, resulting in 
the end of the waiting condition. Accordingly, the signal S3 turns to 0 
simultaneously with the end of the wait condition, whereupon the drum 
stops and the first prerotation comes to an end. 
On the other hand, if the first prerotation is required at least for the 
time T5 (equivalent to a little less than 2 revolutions of the drum), the 
drum is rotated for the time T5 even if the wait time is shorter than the 
time T5. 
(Refer to FIG. 8C). 
As above, according to this invention, by giving priority to the wait 
status end signal over the specified first prerotation time signal, it is 
possible, without providing a surplus waiting time, to effect the first 
prorotation process for a proper time and prolong it the longer the 
leaving time is. 
During the first prerotation, as in the time charts in FIGS. 4 and 22A-22D, 
the lamp 3 and the corona discharger 6, etc. are lit (weak) for 
equalization of surface potential. In FIGS. 22A-22D, ROT2 and ROT3 
represents essential rotation corresponding to T5, with the latter 
effecting equalization by lowering the secondary charger output. For 
instance, by inputting S3 to CPU 2 as in FIGS. 15A-1 through 15A-3 and 
counting pulse CL, T5 drum rotation can be continued. 
Further, in cases where an improvement of image quality can be expected the 
longer the first prerotation process is due to differences in apparatus 
configuration or type of sensitive element, being not limited to the 
present embodiments, copy image quality improvement can be achieved by 
carrying out the first prerotation process until availability of the 
copying conditions and as far as the power switch is on even if not only 
the temperature conditions of the fixing means, but also other conditions 
making copying impossible such as availability of transfer material and 
developer and various other impossible conditions were existing. 
In the meantime, in cases where it is not advantageous to rotate the 
sensitive element in the condition where transfer paper is jammed at time 
of the power switch ON and so on, it is desirable to prohibit the first 
prerotation. 
The circuit is illustrated in FIG. 7C. That is, the output S1 is controlled 
by the gate G100 to which the signal JAM is inputted. The signal JAM is 
outputted at time of switch ON if the interlock to be mentioned 
hereinafter is not released. Accordingly, S1 is interrupted during 
continuance of JAM condition and therefore the rotation time does not 
start. Similarly, the rotation is interrupted by the detection signal 63S 
if paper is remaining at the paper sensor 63 when the switch is on. 
(Rotation at time of JAM) 
FIG. 13 represents an example of the drum sensitive element processing 
control circuit at time of occurrence of jamming. In this figure, 401 is 
the sequence controller CPU2 to control operation of the copying apparatus 
in FIG. 1, controlling loads in accordance with the time chart shown in 
FIG. 4. Further, the output signal A of the sequence controller 401 is the 
operating signal IEXP for the main motor to drive the drum, etc. in FIG. 4 
as well as for the exposure lamps, the signal B is the corona generating 
signal HVT 1 for predischarger, primary charger and transfer charger, the 
signal C is a signal HVT 2 to generate secondary corona simultaneously 
with exposure and the signal D is a signal JAM to be generated on 
detection of sheet JAM. On the other hand, 405 is a timer circuit for 
delay of operation when input changes from high level, with the operation 
being as in FIG. 6. 
Further, as output D, the detection signal is outputted in the case of 
other troubles and the power switch cut-off detection signal is outputted 
in case the power switch 39 is turned off during revolution of the drum 2. 
In the latter case, as the power source for loads 402 and 404 as well as 
for CPU, a backup power source using condenser or battery is employed. 
Thereby, even if copy operation is interrupted due to detection of JAM or 
other troubles, the drum 2 is stopped after some revolution, during which 
time electric charges by the primary charger, etc. are eliminated. 
In cases where jamming as in the description of operation does not arise, 
each output of the sequence controller 401 is generated according to the 
time sequence shown in FIG. 4 and the JAM output D is not outputted and 
therefore I/O of the inverter 406 is 1 and the output of the timer 405 is 
1, thus controlling the AND gates 402, 403 and 404 on, and consequently a 
normal copying is effected. On the other hand, output of the inverter 407 
is 0 and accordingly no JAM indication takes place. 
In cases where jam occurs during copying or the abovementioned halogen lamp 
is burnt out during copying, the signal JAM is set in the output D and JAM 
is indicated via the inverters 406 and 407 and at the same time, 0 is 
transmitted to the input of AND gate 403 and accordingly the operation of 
the primary and transfer chargers and predischarger is cut off. Further, 
since the input to the timer 405 is changed from 1 to 0, the timer 405 
starts timer operation from such point of change and, after the lapse of a 
fixed time T.sub.10, turns its output to 0. The signal is transmitted to 
the AND gate 402 and 404 and the exposure lamp, main motor and secondary 
corona charger are cut off. In the meantime, the backward clutch is 
actuated in such manner as to reset the platen forcibly to the stop 
position (switch 35) in the time T.sub.10. 
That is to say, in the case of occurrence of JAM, simultaneously with JAM 
indication, the primary and transfer chargers as well as predischarger are 
cut off and after the lapse of the fixed time T.sub.10, the secondary 
corona, main motor and exposure lam; are cut off. By setting the time 
T.sub.10 to a time nearly corresponding to a high-tension region between 
primary charger 5 and secondary charger 6 in FIG. 1, a high-potential 
region is eliminated under the effect of lamp light and secondary corona, 
thus eliminating the possibility of residual memory or the development of 
high-tension. Further, the distance between the primary charger 5 and the 
secondary charger 6 is not so large generally and therefore the time 
T.sub.10 can be shortened, thus promoting the jamming condition rarely. On 
the other hand, the shutter 25 is switch-controlled simultaneously with 
occurrence of JAM so as to produce light paths as a and c in FIG. 20. 
Further, in FIG. 1, the drum surface between the transfer charger 90 and 
the predischarger 24 at somewhat high potential and it is possible to set 
the aforesaid timer T.sub.10 in such manner as to evenly discharge the 
said potential to allow it to approach zero. In respect of the 
abovementioned and what is described below, the same applies to jam, lamp 
burn-out and intermediate switch off, too, but the main motor can be run 
to discharge paper except in the case of jam. 
Further, in such type of copying apparatus in which the fixing rollers 201, 
202 (rotated by the main motor) are pressed during copying in utilizing 
its turning force and such pressure is relieved after copying, it is also 
possible to set the said timer time T to the time required for release of 
pressure. It is thereby possible to prevent the rollers from being left 
under pressure at time of jamming and deformed. 
On the other hand, similar to post-rotation after the end of a preset 
number of copies after jam (called "cycle-out post-rotation"), for the 
purpose of reducing the effect of the secondary charger 6 and/or lamp 
light by jam output D, it is also possible to lower impressed voltage to 
them and thereby allow drum surface to further approach zero. That is, as 
in FIGS. 21A and 21B, the drum is stopped after about half revolution. 
Further, in case the time of the abovementioned cycle-out post-rotation 
T.sub.20 (ROT 1+ROT 2+ROT 3) and the time of rotation after jam T.sub.10 
are different and in case they are equal as well, for the purpose of a 
further approach to zero potential and for removal of potential 
irregularities, it is also possible to operate the loads 402 to 404 at 
voltages corresponding to these times. In addition, T.sub.20 &gt;T.sub.10 is 
preferable. 
On the other hand, during rotation after jam, the movement of the conveying 
belt 19 is stopped so as not to make jammed condition complicated. 
Further, it is possible to effect control in such manner that the 
abovementioned post-jam rotation is prohibited in the case of jam near the 
drum and it is permitted in the case of jam near the fixing rollers. 
It is shown in FIG. 13B. If, at the time when there should be no paper, 
paper is detected at the paper detecting switch 16, JAM 2 is outputted, 
LED (not shown) is lit and all are stopped via OR gates 410, 411. If jam 
is detected at the outlet paper detection switch 63, JAM 1 is outputted 
for processing as described above. 
(Acoustic display) 
FIGS. 15A-1, 15A-2 and 15A-3 are key entry-indication-sequence control 
circuit diagrams. CPU 1 and 2 are one-chip semiconductor microcomputer 
each. In CPU 1, for judgement of the status of start key 40, stop key 41 
and ten key 42, time-divided repeat pulses are outputted from output ports 
KS1-KS4. Each key constitutes a matrix configuration comprising its scan 
line and input line to K1-K4 and dynamically inputs key status into CPU 1 
memory. On input of copy start key 40, stop key 41, ten key 42 and clear 
key 43, CPU 1 operates the 7-segment LED indicator 45 for indication, 
stores the preset number of copies by ten key 42 in the register RST 
(memory RAM) of CPU 1 and controls start, stop and movement of the control 
unit CPU 2 for control of process sequence. The LED indicator 45 is 
segment-selected by conversion of coded DISP signals A-D and 
position-selected for dynamic display. 
Further, on input of various keys mentioned above, CPU 1 drives the key 
confirmation speaker 50 for a short time (milli-second) to inform the 
operator of key input through emission of sound. At this time the control 
unit CPU 1 judges from the signal BP from CPU 2 as to whether copying is 
in progress and prevents input of ten key 42 into memory during copying. 
Further, it receives jam signal JAM from the control unit CPU 2, at which 
time it prohibits input of ten key 42, copy start key 40, stop key 41 and 
clear key 43 into memory. On the other hand, in the case of no input into 
memory, the key confirmation speaker 50 does not emit sound even if key is 
pressed on. In the meantime, when key operation can be started if the 
start key 40 is pressed, it is possible to emit tone from the speaker 50, 
which is different from the one emitted when other keys are pressed. 
The sequence control unit CPU 2 receives copy start enabling signal STB, 
copy start command signal STAT and copy end command signal END from the 
control unit CPU 1 and further, receives the aforesaid clock pulse CL 
generated by revolution of the drum 2 to be driven by the main motor M1 
from the drum clock generating unit DCK, the specified number of which is 
counted in the computer CPU 2 for control of each load according to the 
time charts shown in FIGS. 4 and 22A through 22D. 
As above, drum clock pulse CL is a signal important for sequence control 
and if clock pulse is not generated due to failure of the main motor, 
trouble in the drive system, mechanical or electrical failure of the drum 
clock pulse generating unit DCK and so on, the halogen lamp is on 
continuously, causing a critical trouble to the copying apparatus. For 
this reason, when counting the clock pulses, the sequence control unit CPU 
2 utilizes a built-in timer and if clock pulses are not inputted during a 
fixed time, outputs a clock pulse trouble signal to the line 110 (BZ). It 
outputs the signal from the ports D, D1 in FIGS. 13 and 14 and interrupts 
the sequence. 
The operation time chart is shown in FIG. 16. That is, it drives the first 
timer DT 1 by the motor drive signal M.sub.1, resets DT 1 if pulse is 
generated before time-up of T.sub.1 and drives the second timer DT 2, 
resets DT 2 if the next pulse if generated before time-up of T.sub.1 of DT 
2, taking it as normal, and if pulse CL is not detected before time-up of 
DT 1 and DT 2, outputs BZ signal. Accordingly, the motor and all pulses 
can be checked up. In this way, a warning of trouble is given by causing 
the aforesaid speaker to emit sound continuously or intermittently (as 
BZ') (repeated for several seconds). Further, all sequences shown in FIG. 
4 are interrupted immediately so as to prevent a grave accident of the 
copying apparatus before it happens. In addition, in such case, too, the 
alarm is made conspicuous by operating the speaker 50 with tone different 
from the one at the time of key input (in providing a different acoustic 
frequency). 
On the other hand, the circuit DCK detects holes of a number of perforated 
discs provided in the drum shaft as photo changes by means of a photo 
interrupter comprising L.sub.1 and R.sub.1 and drives the transistor TR 1 
to output CL. 
As above, by a common use of the key confirmation speaker (buzzer) 50, an 
alarm of trouble such as main motor stop, etc. can be given. 
Moreover, abnormal lighting of lamp, abnormal lighting of heater, 
disconnection of thermistor 24 and sheet jamming, etc. are detected and an 
alarm can be given in using the abovementioned buzzer. 
In addition, by changing the sound emission period of the speaker (buzzer) 
according to various abnormal conditions such as jamming, failure in 
forward and backward clutches, troubles in various drive amplifiers, no 
paper within the cassette and no toner in the developing unit, etc., alarm 
and identification of various conditions can be performed by means of a 
single member. This is made possible, as in FIG. 15B, by selecting, 
according to various detecting signals such as JAM detection 49, etc., one 
of the output ports n.sub.1 . . . n.sub.n of CPU 1 and operating one of 
the oscillators 50-1 to 50-n different in frequency. 
In addition, depending on the abovementioned abnormal conditions, the 
operator's attention may be called by expressing the condition in question 
in voice statement (message). In this case, a small speaker is used rather 
than a buzzer. As a thin type, a piezo-electric speaker is preferrable to 
the M-M and M-C types. By storing the voice statement information as codes 
beforehand in the memory for exclusive use for read-out of CPU (program 
memory ROM for sequence or separately provided read-out memory ROM), 
reading the information by a trouble detection signal and converting it, 
under a known system, into voice and outputting it to the speaker via an 
audio amplifier, the audio representation can be achieved and, as 
mentioned previously, the speaker can also be used for key sound emission. 
Further, by storing the aforesaid message to inform wait-up and a message 
to inform proceeding to the post-rotation mode as aforesaid in ROM as 
audio informations, it is possible to read out each message according to 
the signals WAIT and CTU and cause the said speaker to emit sound. 
An example of these circuit diagrams is shown in FIG. 15C. Either CPU 1 or 
CPU 2 may have the voice statement program memory, but in this example, 
CPU 2 has it. CPUs 1 and 2 have the same function as in FIGS. 15A-1 
through 15A-3. 501 is a white noise source, 500 a converter to filter 
noise from 501 by control signal .alpha. regarding the statement from CPU 
2 and convert into statement analog signal and the audio amplifier an 
amplifier to drive the speaker 50 with the conversion signal. 
The functions of CPU 1 and CPU 2 can be executed by one microcomputer 
conmprising one-chip semiconductors inclusive of RAM and ROM, which is 
generally caled CPU. The above and following sequence control, display 
alarm and entry control, etc. can be achieved easily with program 
softwares. (Jam reset, half-open door checking) 
FIG. 17 is a circuit diagram for jam indication, jam reset and half-open 
door checkup of housing door. FIG. 18 is an oblique view when the housing 
door 101 is opened. 
In FIG. 17, CPU is, as previously mentioned, a control unit to detect sheet 
jamming and 100 a microswitch provided in the housing door 101 for 
detection of half-open condition of the housing door, with its normally on 
indicating the door closed normally. 
102 is a transistor to be on when detecting half-open door, 103 LED to 
indicate half-open door and sheet jam conditions, which corresponds to 49 
in FIG. 3, and 104 a door switch to detect closing of the door 101 
provided on the body side 105, which will be on when the door is closed. 
105 is a condenser for jam resetting, 106 a diode for reverse-current 
interruption, 107 a latch relay for jam hold, 108 (S) a coil to set the 
latch relay and turn on the switch 109, 108 (R) a coil to release the 
latch relay and turn off the switch 109, 110 a transistor to be on by the 
JAM detection signal JAMS from CPU and 111, 112 are diodes for consumption 
of induced current at time of coils 108 and 109 OFF. 
The operation will now be described in the following. If it is assumed that 
the housing door 101 is closed, the door switch 104 is on and the 
transistor 101 is turned on by the jam detection signal JAMS from CPU and 
sets the set coil 108 (S) with power source V. Thereby the switch 109 is 
closed, turning LED 103 on, and the jammed condition is indicated by the 
indicator 49. This condition is maintained even if there is no more signal 
JAMS under action of the latch relay 107. At the same time, the signal JAM 
to stop the machine is inputted to CPU. Thereupon, CPU causes, as 
mentioned hereinafter, sequence processes such as fixing heater OFF, 
copying interruption (before completion of one process) and drum 
post-rotation, etc. to be executed. 
If the door 101 is opened at the time of occurrence of jamming, the door 
switch 104 is turned off, LED 103 goes out and power to CPU is cut off. On 
the other hand, the half-open door 100 is closed. In the meantime, since 
the condenser 105 has been charged through the diode 106 before the door 
switch 104 was turned off, by opening the door 101, its charge switches on 
the reset coil 108 (R) of the latch relay 107 via the switch 100 and opens 
the switch 109 as illustrated. Thereby LED 103 display, etc. is prevented 
when the door 101 is closed after release of jam holding and removal of 
jammed sheet. 
In the meantime, since charges at the condenser 105 are held for about 
scores of minutes, a sufficient function is displayed for relief of jam 
after cutting power off by means of the door switch 104. Accordingly, in 
comparison with conventional cases where spring or claw, etc, is employed 
to hold a jammed condition mechanically and relieve the claw by means of a 
manual push button after disposal of jamming, jam resetting is now 
possible under quite a simple construction. 
In the apparatus of this embodiment, the drum and the main motor to drive 
it are provided on the side of the door 101 and the sheet conveying belt 
19 and the fixing roll 20, etc are provided on the side of the apparatus 
proper 105. And these roll and belt are drive-connected to the main motor 
with the gear 113 (FIG. 18). Accordingly, when the door 101 is closed 
after elimination of jamming, if the door is not closed completely, the 
gear 113 will not be engaged and if, in such condition, copying is started 
in the copying apparatus, the machine parts will be damaged. 
To prevent such trouble, the half-open door switch 100 serves for the 
purpose. That is to say, if the door is not closed completely, the door 
switch 104 is closed and the half-open door switch 100 is also closed. 
Consequently the transistor 102 is switched on by the power source V via 
the diode 106 and connects LED 103 to earth to cause it to be on or to 
flash. At the same time, a stop signal as at the time of jamming is 
inputted to CPU to make copy start impossible. If the door is closed 
completely, the switch 100 opens to stop LED 103 indication and the stop 
signal, too, is switched off to make copying possible. For the purpose of 
flashing indication, the transistor 102 may be made an oscillation type. 
In this embodiment, the half-open door switch 100 is interlocked with the 
lever 114 to open manually the door 101 locked with the apparatus proper 
and turned on immediately on opening of the lever and can detect a 
delicate condition of the door. Its operating condition is shown in FIG. 
19. 115 represents the interlocking lever and the switch 100 is turned off 
by the movement in the direction of arrow by the lever 114. 
On the other hand, display can be discriminated by providing LED for 
display of half-open door condition in distinction from jam display and by 
causing LED 103 to flash at time of jamming and to light statically at 
time of half-open door. Further, since the half-open door switch 100 can 
be regarded as a switch for jam resetting as mentioned previously, the 
abovementioned half-open door checkup and jam resetting can be carried out 
by means of one switch, thus making it possible to provide quite a simple 
control unit. 
On the other hand, it is feasible to employ a battery as the condenser 105. 
(Jam elimination) 
In FIG. 17, the switch 116 is a switch provided on the circuit base plate 
within the apparatus, which serves to prohibit input of machine stop 
signal due to jamming to CPU and thereby, even in the case of jamming, 
cause copy run to continue to the last, that is, effect run as in normal 
conditions. Accordingly, it is possible to effect copying without sheet 
feed and check up machine operation without paper loss. 
The operation will be described in the following. If the switch 116 is 
turned on, a signal outputted on detection of JAM detection from CPU is 
bypassed by 116 and the transistor 110 won't be switched on. Consequently, 
the latch relay 107 will not be set, not generating the jam stop signal. 
Accordingly, CPU effects jam checking, but sequence processes such as 
heater-off, high-tension off and drum post-rotation, etc. are not carried 
out and copying will continue. 
However, since interlock by the half-open door switch holds priority, copy 
operation is interrupted irrespectively of the switch 116 at the time of 
detection of half-open door. The degree of safety is elevated thereby. 
This way of thinking serves for the elevation of the degree of safety even 
in a machine test run by jam differentiation as mentioned above in cases 
where malfunction with different objects is cautioned in using the same 
indicator or the same control circuit is employed or where after detection 
of malfunction, post-rotation of a similar degree as mentioned previously 
after detection of malfunction is effected. 
(Process bright/dim sequences) 
FIGS. 21A and 21B are operation time charts for one-sheet copying (size A3) 
and FIGS. 22A through 22D detailed time charts in the case of A3 two-sheet 
copying and A4 manual supply copying. 
The halogen lamp is lit dimly during the first and second prerotation and 
post-rotation (LA 1). In this embodiment, lamp voltage is changed to 
change the quantity of light for setting tone gradient and dim lighting of 
lamp mentioned above means lighting condition in quantity of light set 
equal to or lower than the minimum quantity of light set as above. During 
performance of the process, lamp is lit brightly, that is, according to 
preset brightness. 
For blanking exposure, light from the halogen lamp is radiated over the 
drum by opening the shutter 25 during non-image exposure (FIGS. 20A and 
20C). Accordingly, during pre- and post-rotation, dim light mode similar 
to the above-mentioned lamp LA 1 is applied. From the start of copy cycle 
to the time when the platen reaches the exposure start position, the drum 
is radiated with dim blanking light. Accordingly, until directly before 
image exposure, the drum surface is exposed uniformly and potential 
equalized. On the other hand, at the start of cycle the lamp LA 1 is lit 
bright to make preradiation light bright via the changer 24. However, the 
surface preceding the drum surface over which such light is radiated 
(surface from the charger 24 to 6) is processed with dim light and 
therefore latent image mottle may be produced on image exposure at the 
boundary between bright and dim zones. Accordingly, the dim light process 
zone is excluded from the latent image forming surface. Further the 
surface is subjected to blanking exposure for bright light processing and 
therefore mottles can be avoided. In addition, the time (the initial 
backward time to have the platen reach the switch 30) is caused to 
correspond beyond such zone and therefore there is no waste of time. 
For preexposure and overall exposure, lighting synchronous with the halogen 
lamp and a bright-dim sequence are carried out. The preexposure has the 
function of eliminating a residual image after transfer. 
Further, owing to bright-dim control of the lamp, temperature rise of the 
platen surface and the surrounding members is prevented and lamp life is 
protected. In particular, since the fiber array 27 is employed in the 
optical system for image exposure, the apparatus is compact, preventing 
temperature rise of the surroundings liable to be caused by the halogen 
lamp. 
The secondary charger is operated at low voltage in the second mode of 
postrotation (ROT 3). (-) corona component is thereby weakened and 
potential equalization and approach to zero potential on the drum surface 
are possible at the time of drum stop at the end of postrotation. 
On the other hand, as in FIGS. 21A and 21B, after the primary charger OFF, 
the secondary charger and the lamp are operated weakly and therefore it is 
possible to eliminate residual charges in the portion from the primary 
charger 5 or the transfer charger 90 to the secondary charger or light 
radiation surface downstream in the revolving direction of the drum 2. 
Consequently, at the time of drum stop at 180.degree., the entire drum 
surface can be discharged evenly for uniform approach to zero. 
The timing of switching of the blanking shutter and the timing of voltage 
switchover of the secondary charger are determined by counting a specified 
number of the aforesaid drum clock pulses. The clock counting is shown as 
CL in the "clock count" column of FIGS. 22A-22D (time chart). The shutter 
25 shuts off the blanking light on solenoid-on signal (SHUT) from CPU. 
FIGS. 20A, 20B and 20C show the sequence operation of platen light via the 
secondary corona charger 6, overall exposure via the mirror 26, 
preexposure via the mirror 28 and blanking light via the shutter 25, in 
which (a) indicates the first revolution of the drum after copy key ON, 
(b) the second revolution of the drum, platen exposure, and (c) cycle end, 
that is, the fifth revolution of the drum and platen stop. (Lamp 
regulator) 
FIG. 23 shows a circuit for switchover of lamp light, in which IEXP 
represents lamp-on signal from CPU, V1 output voltage for bright exposure 
as set by a lamp regulator (not shown), VR601 a resistor for light 
quantity control by the gradation lever 44 of the control unit, Q209 a 
circuit to set, as desired, the light quantity adjusting range with VR601 
and serve for shift change of center light quantity while maintaining the 
range, V2 output voltage for dim exposure, LINT output of dimmer signal 
and lighting signal to the lamp regulator (not shown) (whereby lamp is lit 
and operated at a desired quantity of light), K201 a relay for bright-dim 
switchover, SIEXP a light quantity changeover signal from CPU and LINTT a 
voltage signal obtainable from a light quantity compensation timer (not 
shown) and varying with the duration of copy pause. The longer the pause 
is, the more the quantity of light at the initial period of switchover to 
bright light is increased. 
The operation will now be described. If IEXP is outputted from CPU 
synchronously with the main motor, specified voltage V1 is outputted from 
the regulator for impression of rated voltage upon the lamp at time of 
max. light quantity. Within the dimer limits to be determined by R209 and 
R210, dimmer voltage is set by the dimmer volume VR601 and Q209 outputs a 
strong signal voltage. This voltage can be shift-adjusted by means of the 
resistor VR206. 
On the other hand, if machine operation is resumed in a copy pause 
condition, initially the sensitivity of the sensitive material is 
recovered and high and irregularities in density are produced in latent 
images between the first sheet and the fourth or fifth sheet. Further, 
such irregularities are more conspicuous when the time of copy pause was 
longer, but do not appear when there was little pause. Accordingly, in 
this embodiment, the quantity of light of the lamp is controlled according 
to the time of pause so as to be able to copy the first and subsequent 
sheets at the same density irrespectively of the length of time of pause. 
That is to say, a condenser to discharge during pause and charge during 
copying is provided and light quantity adjustment is made with output 
voltage LINTT corresponding to condenser charging voltage. That is, the 
longer the time of pause, the lower the voltage LINTT and at the time of 
resumption of copying, Q209 outputs set voltage shifted down somewhat and, 
with performance of copying, LINTT and Q209 set voltage rise and increase 
the quantity of light, which returns to a fixed quantity of light on 
completion of condenser charge. On the other hand, in case the pause time 
is short, the voltage LINTT is not so low and therefore a change in light 
quantity is small. 
The condenser is charged simultaneously with prerotation ROT 4 and 
discharged when postrotation begins. On the other hand, at the time of 
premultirotation ROT 1, no charging takes place. This is because the 
premultirotation ROT 1 is a rotation not contributing to latent image 
formation, for which reason no light quantity adjustment is made. During 
the premultirotation ROT 1, the photosensitive material is exposed weakly 
for recovery of sensitivity to some extent and subsequently, with 
prerotation ROT 4, light quantity adjustment is made, whereby a stable 
latent image is formed. In this embodiment, the condenser discharge time 
is quite longer than the charge time. 
The level H (strong exposure) of the light quantity switchover signal SIEXP 
from CPU to be outputted at the specified timing switches the relay K201 
on and Q209 strong signal voltage is outputted as a dimmer output LINT. 
During prerotation and postrotation, SIEXP is at the level L and 
therefore, as mentioned above, a weak signal voltage V2 is outputted as a 
dimmer output LINT. 
Bright-dim light timing is shown in FIGS. 22A-22D. For lighting with bright 
light during CBFW, first dim light during ROT 1-ROT 3 and second dim light 
between the abovementioned bright light and first dim light in other 
cases, SIEXP is caused to output synchronously with CBFW and sample V2 
output and R210-R209 connection point output can be given by switching. 
Thereby more appropriate potential equalization effect is obtained and the 
life of the halogen lamp can be extended. 
On the other hand, since the carriage is stopped at time of dim light, 
shortening of life due to shock is small. Further, as in FIGS. 22A-22D, at 
the time of carriage stop, the same current as at the beginning of forward 
feed is applied to the forward clutch for a fixed short time to apply 
reverse power and therefore the carriage can be stopped correctly and soft 
at the specified middle position without any mechanical stopper. The 
forward clutch transmits power of the main motor to the carriage, while 
the backward clutch increases the backwad speed via gear. In the meantime, 
by setting the timing of switchover of lamp to bright light a little later 
than the timing of switchover of carriage from backward to forward and the 
timing of switchover to dim light a little earlier than the timing of 
switchover from forward to backward, it is possible to cause shock at time 
of movement reversal to correspond to the time of dim lighting. 
On the other hand, concerning the lamp regulator, Japanese Patent Laid-Open 
Publication No. 90180/1976 of the Applicant is known, while the circuit 
209 is described in detail in Japanese Patent Application No. 8273/1978. 
(Drum heater control) 
For the purpose of preventing the photosensitive drum from being 
deteriorated due to temperature, humidity and other environments and 
affecting copy image quality adversely, the drum heater is mounted in the 
drum shaft. 
FIG. 24 is a drum heater control circuit, in which 120 is a heater provided 
as an extension in the longitudinal direction of the shaft and TS1 and TS3 
are thermo-switches provided near the reverse side bottom plate in the 
interior of the apparatus proper for detection of machine atmosphere, 
whose working temperatures are different from each other. SW 1 is the main 
switch of the control unit, MS 1 and MS 2 are the door switches (104) 
provided at locations illustrated for bilateral power cut-off, CB 1 a 
breaker, LF 1 a low pass filter and DS 5 a diode to feed half-wave to the 
heater 120. 
In this embodiment, under three conditions of TS 1, TS 3 and SW 1, 5 modes 
of heater power supply are provided to effect drum heating at high 
accuracy. That is, overheating of a drum to over 45.degree. C., for 
instance, causes fusion or solidification of toner on the drum and 
therefore, to prevent such danger, dehumidification and proper temperature 
are ensured effectively. 
FIG. 24 shows main switch (SF 1) and door switches (MS 1, MS 2) being all 
in OFF state. The operating conditions are as shown in the following 
table. 
TS 1 is turned on (closed) below 32.5.degree. C. and off (opened) at above 
39.5.degree. C. 
TS 3 is turned on (closed) below 16.degree. C. and off (opened) at above 
23.degree. C. 
The drum heater H1 has a rating of 15 W (at time of ON) and consumes 7.5 W 
(at time of half-wave rectification). 
__________________________________________________________________________ 
Temperature 
Below 16.degree. C. 
16.degree. C.-23.degree. C. 
23.degree. C.-32.5.degree. C. 
32.5.degree. C.-39.5.degree. C. 
Above 39.5.degree. C. 
__________________________________________________________________________ 
TS1 ON ON ON ON or OFF 
OFF 
TS3 ON ON or OFF 
OFF OFF OFF 
Drum 
SW1 
ON ON or Half-wave 
Half-wave 
Half-wave 
OFF 
Heater 
OFF 
(Full wave) 
rectification 
rectification 
rectification 
(H1) or OFF 
SW1 
ON ON or OFF 
OFF OFF OFF 
ON 
__________________________________________________________________________ 
(Fan motor) 
In FIG. 1, besides the exhaust fan and the suction fan, an exhaust blower 
is provided near the fixing means for cooling of the fixing means, 
carriage and document lamp, etc. 
FIG. 25 shows a circuit for control of blower and exhaust fan, in which FM 
3 and FM 2 are blower motor and exhaust motor, respectively, TS 2 is a 
thermo-switch provided near the fixing means to detect its temperature and 
SW 1 the main switch. 
Each is provided with a fan motor, with the suction fan motor FM 1 being 
synchronous with operation of the main motor. 
The exhaust fan FM 2 and the blower motor FM 3 are provided to prevent 
temperature rise and operate at the time of the power switch ON and the 
thermo-switch TS 2 ON when the power switch is OFF. 
In the meantime, TS 2 ON takes place at over 55.degree. C. and OFF at below 
45.degree. C. 
The suction fan FM 1 is provided in the machine on the side where the 
developing means is provided. Accordingly, if developing toner is 
replenished with the power switch SW 1 ON, the toner may fly up and 
contaminate the machine interior. Accordingly, due attention should be 
paid to replenishment of toner. In this embodiment, the suction fan FM 1 
is synchronous with the main motor. This fan is stopped at the time of 
replenishment of toner and therefore the abovementioned disadvantage can 
be prevented. 
(Total counter) 
The mechanical copy counter will be described with reference to FIG. 26. In 
this figure, CNT 1, CNT 2 and CNT 3 are the known mechanical counter to 
count and memorize a total number of copies irrespectively of copy key and 
main switch (total counter independent of sizes), total counter of copies 
of sizes B4 and A3 and total counter relative to sizes A4 and B5, 
respectively. 
In cases where a copy counter is connected, +24 V is supplied to the anode 
of LED 203 via the coil of the copy counter and LED 203 is lit and inputs 
0 to Q204, thus making copying possible. 
In cases where the copy counter is disconnected or removed, the anode 
potential of LED 203 becomes zero. And Q205-1 becomes 0, Q204-13 to 1 and 
Q203-4 to 0, making copying impossible. On the other hand, however, if a 
counter drive signal is given during copying, 0 is inputted to Q203-4 and 
copying is possible. 
In cases where the copy counter is disconnected or removed, the anode 
potential of LED 203 becomes 0 V, resulting in Q205-1 to 0, Q204-13 to 1 
and Q203-4 to 0, making copying impossible. However, if a counter drive 
signal is given during copying, 0 is inputted to Q203-4 and copying is 
possible. Q204 inputs WAIT signal, enabling the same sequence stop mode as 
mentioned above. The same control is possible in the case of the counter 
OFF, too. 
The said counter applies +1 on a small copy signal SCNTD and a large signal 
LCNTD. These signals are outputted with CPU detecting and discriminating 
the sizes of casettes used. On the other hand, the output timing 
corresponds to the time of move of the platen to the reversal point. In 
addition, such point turns the memory counter within CPU for display 45 to 
-1. 
In this embodiment, jam detection is effected in the following way, that 
is, in cases where the paper detector 13 provided at the outlet of the 
sheet path does not detect a sheet at a specified time of process, it is 
determined locally to be a jam before the detector, whereas in cases where 
a sheet top actuates the detector and the timer and, within the timer 
time, the sheet does not come off the detector and the sheet is detected 
even after the end of timer time, it is determined to be a jam near the 
detector (in the vicinity of the fixing means), and in each of the above 
cases the signal JAMS is outputted. Further by discriminating them as JAMS 
1 and JAMS 2, they may be used for the abovementioned rotation control and 
display control.