Copying apparatus with a movably mounted original table

In a copying apparatus, an original image signal is obtained by optically scanning an original surface using an original rest slidably mounted on a housing. The copying apparatus has a construction for detecting malfunctions such as a paper jam or a toner empty state, and a mechanism for forcibly moving the original rest to a position suitable for eliminating a paper jam or a position suitable for replenishing the toner, when these malfunctions are detected.

BACKGROUND OF THE INVENTION 
The present invention relates to a copying apparatus which is arranged such 
that a moving table having an original or a light source is moved so as to 
perform a scanning operation of the surface of the original using light 
from the light source. 
In copying apparatus of this type having an original rest on which an 
original is placed, a copying machine is known wherein an upper unit 
holding the original rest can be opened to be inclined with respect to a 
lower unit about one hinged end thereof. According to this arrangement, 
when a paper jam occurs in a copying machine main body, an operator can 
open the upper unit to pick up a jamming paper sheet from the interior of 
the copying machine. In this case, since the original rest is movable with 
respect to the upper unit, when the upper unit is inclined carelessly, the 
original rest moves along the upper unit due to gravity, thereby damaging 
the original rest or the copying machine main body due to the impact of 
this movement. 
On the other hand, in copying apparatus of original rest moving type, a 
toner replenishment port of a developer is generally provided in the way 
of a moving path of the original rest. Generally, since a stop position of 
the original rest (in the non-copying mode) is set at a position at which 
the toner replenishment port is covered, when a toner empty state is 
displayed on a display panel, the operator must manually move the original 
rest so as to open the toner replenishment port. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a copying apparatus 
which, in a copying apparatus which moves a moving table having an 
original or a light source for scanning a surface of an original, can 
easily perform maintanance and check operations without causing damage due 
to an impact of movement of an original rest by the careless operation of 
an operator, when a malfunction such as paper jam or toner empty state 
occurs. 
According to the present invention, in order to achieve the above object, 
there is provided a copying apparatus, having a moving table slidably 
mounted on a copying apparatus main body, which comprises a means for 
detecting a malfunction of the copying operation and a means for stopping 
the moving table at a predetermined position in response to a malfunction 
detection signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1A and 1B schematically show the operation of an embodiment of the 
present invention, respectively. In FIG. 1A, an original rest 3 is mounted 
on an upper unit 1a of a copying apparatus housing 1 to be slidable along 
a horizontal direction indicated by the arrow b. The upper unit 1a is 
hinged to a lower unit 1b at one end H thereof, and is arranged to be 
freely opened/closed to the lower unit 1b. 
Assume that a paper jam occurs for any reason during the copying operation. 
In this case, this paper jam is detected by a paper jam detecting 
mechanism provided in the housing 1, and the copying operation is thereby 
stopped. Assume that the original rest 3 is stopped at a position shown in 
FIG. 1A. This position of the original rest 3 is detected by an original 
rest position detecting mechanism provided in the housing 1. Then, the 
original rest 3 is forcibly moved by an original rest driving mechanism to 
a prescribed original rest stop position, i.e., in this case, a position 
shown in FIG. 1B. 
When a paper jam state is displayed on a display panel (not shown) of the 
housing 1, an operator lifts up the upper unit 1a and picks up a jamming 
paper sheet from an exposed paper sheet convey path, thereby restoring a 
function of the copying apparatus. 
An arrangement of this embodiment will be described with reference to FIGS. 
2 to 13 hereinafter. In FIG. 2, a photosensitive drum 2 is mounted at a 
substantially central portion in the upper unit 1a of the housing 1 so as 
to rotate in a direction indicated by the arrow a. The original rest 3 
which supports an original is mounted on an upper surface of the housing 1 
so as to reciprocate along a direction indicated by the arrow b. 
Therefore, the original rest 3 is moved in syncronism with the rotation of 
the photosensitive drum 2. Then, light irradiated from an exposure lamp 4 
is reflected by the original placed on the original rest 3, and this 
reflected light forms an image (i.e., an inverted image of an image on an 
original) on the photosensitive drum 2 by a converging light transmission 
body 5. In this case, the inverted image is formed as an electrostatic 
latent image on the photosensitive drum 2 upon charging the photosensitive 
drum 2 with a charger 6. Toner is applied on this latent image by a 
developer 7, thereby forming a toner image. 
On the other hand, a paper feed mechanism 8 for feeding a paper sheet P 
below the photosensitive drum 2 (i.e., an image transfer unit 12) is 
provided in the lower unit 1b below the developer 7. The paper feed 
mechanism 8 comprises a paper feed cassette (paper storing unit) 9, which 
is detachably mounted at a side of the housing 1, for storing a plurality 
of the paper sheets P and a paper feed roller (paper feed means) 10 for 
feeding the paper sheets P one by one from the paper feed cassette 9. In 
addition, the paper feed mechanism 8 comprises a pair of aligning rollers 
(conveying means) 11a, 11b for aligning a leading edge of the paper sheet 
P fed by the paper feed roller 10 and conveying it. The paper feed roller 
10 is a roller having a semi-circular cross-section and a contact portion 
10a and noncontact portion 10b with respect to the paper sheet P. Driving 
power of a motor is transmitted by turning on a solenoid of a spring 
clutch (to be described later) for rotating the paper feed roller 10, and 
the paper feed roller 10 is stopped after rotating through a predetermined 
angle (e.g., 210 degrees). 
Therefore, the paper sheet P conveyed by the aligning rollers 11a, 11b is 
fed to the image transfer unit 12. The paper sheet P which is fed to the 
image transfer unit 12 is brought into tight contact with the surface of 
the photosensitive drum 2 at a portion of a transfer charger 13, thereby 
transferring, by charging the paper sheet P with the charger 13, a toner 
image formed on the photosensitive drum 2. Then, after the transfer 
operation, residual toner on the surface of the photosensitive drum 2 is 
removed therefrom by a cleaner 14, and a residual image is discharged by a 
discharging lamp 15, thereby restoring the drum 2 to its initial state. On 
the other hand, after the transfer operation, the paper sheet P is 
electrostatically peeled from the photosensitive drum 2 by the operation 
of a peeling charger 16, and thereafter is conveyed along a convey path 17 
to a pair of heat rollers 18a, 18b. Then, by passing through the heat 
rollers 18a, 18b, the transferred image is thermally fixed on the paper 
sheet P. Thereafter, the paper sheet P is discharged by a pair of paper 
discharging rollers 19a, 19b onto a tray 20 which is provided outside the 
housing 1. The photosensitive drum 2, the original rest 3, the developer 
7, the paper feed roller 10, the aligning rollers 11a, 11b, the heat 
rollers 18a, 18b and the paper discharging rollers 19a, 19b are operated 
by a motor 21 as a driving source. 
A switch (which will be referred to as a paper feed switch hereinafter) 22 
is provided near (in front of) the aligning rollers 11a, 11b as a detector 
for detecting a paper feeding state. Furthermore, a switch (which will be 
referred to as a paper discharging switch hereinafter) 23 is provided near 
(in front of) the paper discharging rollers 19a, 19b as a detector for 
detecting a paper discharging state. These switches 22 and 23 are provided 
mainly for detecting a paper jam occuring therebetween. 
Note that the housing 1 is divided into the upper and lower units 1a and 1b 
by the convey path 17, as indicated by the two short dashed and alternate 
long line in FIG. 2. The upper and lower units 1a and 1b are pivotally 
supported on a pivot shaft (not shown) provided at one end H thereof, and 
the unit 1a can be opened in a direction indicated by the arrow c to a 
predetermined angle. In the upper unit 1a, the photosensitive drum 2, the 
original rest 3, the exposure lamp 4, the converging light transmission 
body 5, the charger 6, the developer 7, the paper feed roller 10, the 
upper aligning roller 11a, the cleaner 14, the discharging lamp 15 and the 
like are provided. On the other hand, in the lower unit 1b, the paper feed 
cassette 9, the lower aligning roller 11b, the chargers 13 and 16, the 
convey path 17, the heat rollers 18a, 18b, the discharging rollers 19a, 
19b, the tray 20, the motor 21 and the like are provided. A toner hopper 
7-2 is provided in a portion above the developer 7 facing the travelling 
path of the original rest 3. A toner replenishment port 7-3 of an upper 
portion of the toner hopper 7-2 is closed by a hopper cover 7-4. The 
detailed configuration of these parts will be described later. 
FIG. 3 shows the original rest driving mechanism. Driving power of a gear 
31 directly coupled to the motor 21 is transmitted to an electromagnetic 
clutch 36 through gears 32, 33, 34 and 35 for transmitting power. The 
electromagnetic clutch 36 is switched in accordance with a control signal 
among the state wherein it does not transmit the driving power to a pulley 
37, the state wherein it transmits the power in a forward direction, and 
the state wherein it transmits the power in a reverse direction. The 
driving power transmitted to the pulley 37 is transmitted to the original 
rest 3 by a wire 38, two ends of which are fixed to the original rest 3, 
thereby moving the original rest 3 in forward and backward directions. A 
pulley 39 is provided for regulating the wire 38 so as to be substantially 
parallel to the original rest 3 and not to be in contact with other 
portions. 
FIG. 4 shows the paper feed roller driving mechanism. The paper feed 
rollers 10-1, 10-2 having a semi-circular cross-section are fixed to a 
rotating shaft 41 one end of which is fixed to a sleeve 42. The sleeve 42 
is coupled to a gear 43, to which the driving power of the motor 21 is 
transmitted through a spring clutch (not shown). In other words, the 
driving power of the gear 43 is transmitted to the sleeve 42 through the 
spring clutch. Projections 44 and 45 are provided on a peripheral surface 
of the sleeve 42 at positions shifted along the axial direction of the 
rotation shaft 41 by an angle of about 210 degrees. The driving power of 
the gear 43 is transmitted to the sleeve 42 unless the projection 44 or 45 
are locked by a lock lever 46. The lock lever 46 is driven by a paper feed 
roller solenoid 47. When the solenoid 47 is turned off, the lock lever 46 
locks the projection 44, as indicated by the solid line. On the other 
hand, when the solenoid 47 is turned on, the lock lever 46 locks the 
projection 45, as indicated by the two dashed line. 
The paper feeding operation will now be described with reference to FIGS. 5 
to 7. Normally, the paper feed roller 10 and other driving mechanisms are 
in the state shown in FIG. 5. (The rollers 10-1, 10-2 in FIG. 4 are 
denoted by numeral 10 in FIGS. 5 to 7, for the sake of simplicity.) Even 
if the driving power of the motor 21 is applied to the gear 43 in a 
direction indicated by the arrow, since the solenoid 47 is turned off and 
the projection 44 is locked by the lock lever 46, the paper feed roller 10 
is not rotated and kept in the state shown in FIG. 5. In this state, if 
the solenoid 47 is turned on, the driving power of the motor 21 is 
transmitted to the sleeve 42 as described above, and the sleeve 42 is 
rotated until the projection 45 is locked by the lock lever 46. 
Simultaneously, the paper feed roller 10 is rotated while feeding the 
paper sheet P stored in the paper feed cassette 9, and still presses the 
paper sheet P having the trailing edge in the cassette 9 as shown in FIG. 
6. Then, the solenoid 47 is turned off in synchronism with the rotation of 
the aligning rollers 11a, 11b, thereby restoring the state shown in FIG. 5 
again, that is, the state shown in FIG. 7. In this case, the paper feed 
roller 10 returns to the same state as shown in FIG. 5 while further 
pushing the paper sheet P, as shown in FIG. 7. 
FIGS. 8 to 11 show the original rest position detecting mechanism. As shown 
in FIG. 8, three magnets 51 to 53 are linearly provided in the original 
rest 3 along the travelling direction thereof spaced by a predetermined 
distance apart, respectively. Furthermore, two magnets 54 and 55 are 
provided to have positions shifted toward the transverse direction of the 
original rest 3 at two end portions of the array of these magnets 51 to 
53. As shown in FIG. 9, in the housing 1, lead switches 56 and 57 are 
provided for detecting these magnets 51 to 55. The lead switch 56 is 
provided to detect the magnets 51 to 53 located thereabove, and the lead 
switch 57 is provided to detect the magnets 54 and 55 located thereabove. 
Therefore, the lead switches 56 and 57 are also provided to have their 
positions shifted in the transverse direction of the rest 3. 
In FIGS. 9 to 11, assume that positions of the magnets detected by the lead 
switch 56 are given by P51, P52 and P53, and positions detected by the 
lead switch 57 are given by P54 and P55. FIG. 9 shows the state wherein 
the original rest 3 is positioned at a home position. The home position is 
a position at which the original rest 3 is stopped when the copying 
operation ends. The home position is detected by the following operations 
wherein, the original rest 3 starts to move in a direction indicated by 
the arrow in FIG. 9 (which will be referred to as a backward direction 
hereinafter) from a movement stop position (which will be referred to as 
an original rest limit position) shown in FIG. 11 and the lead switch 56 
is turned on for the first time, that is, it is turned on by the magnet 
53. The original rest position is detected when only the lead switch 57 is 
first turned on by the magnet 54 during the forward direction of the rest 
3 as shown in FIG. 11. FIG. 10 shows the state wherein the original rest 3 
is positioned at another movement stop position (which will be referred to 
as an original rest start position) along the backward direction. The 
original rest start position is detected when the lead switches 56 and 57 
are simultaneously turned on by the magnets 51 and 54. Furthermore, an 
aligning roller start position is detected by the following operations. 
When the original rest 3 starts from the original rest start position of 
FIG. 10, the lead switch 56 is turned on for the first time, that is, it 
is turned on by the magnet 52, thereby detecting the aligning roller start 
position. As described above, since the photosensitive drum 2 is driven in 
synchronism with the original rest 3, a timing for starting the rotation 
of the aligning rollers 11 can be set not by the original rest 3, but by 
the photosensitive drum 2, such that a leading edge of the image formed on 
the photosensitive drum 2 coincides with that of the paper sheet P. The 
position from which the aligning rollers 11a, 11b start to rotate is the 
aligning roller start position. 
FIG. 12 schematically shows an overall control circuit. Reference numeral 
61 denotes a microprocessor as a main controller for performing the 
overall control operation. Respective input signals generated from the 
paper feed switch 22, the paper discharge switch 23, the lead switches 56 
and 57 (will be referred to original rest switches hereinafter) and the 
like are supplied to the microprocessor 61 through an interface circuit 
62. The microprocessor 61 determines, in accordance with a predetermied 
program stored therein, these input signals and processes them so as to 
generate various control signals which are sent to respective control 
devices. The respective contol devices include the exposure lamp 4, the 
motor 21, the electromagnetic clutch (which will be referred to as an 
original rest clutch hereinafter) 36, the paper feed roller solenoid 47, a 
high voltage source 64 for supplying power to the charger 6, an aligning 
roller solenoid 65 for transmitting driving power to the aligning rollers 
11a, 11b, a high voltage source 66 for supplying power to the transfer 
charger 13 and the peeling charger 16, a blade solenoid 67 for urging a 
blade of the cleaner 14 against the photosensitive drum 2 and the like, 
and they are operated by corresponding control signals, respectively. 
The microprocessor 61 has, for example, a configuration as shown in FIG. 
13. In other words, the microprocessor 61 may be a one-chip microprocessor 
having an architecture as shown in FIG. 13. In FIG. 13, an arithmetic and 
logic unit (ALU) 71 having an arithmetic and logic determination function 
is coupled to each unit through a bus 70. Reference numeral 72 denotes a 
read only memory (ROM) for storing a processing program; 73, a random 
access memory (RAM) for storing data; 74, an I/O controller (IOC) for 
supplying/receiving signals to/from an external circuit; 75, a program 
counter (PC); 76, a flag (FLAG) register; 77, an accumulator (ACC); 78, a 
stack register (STACK); and 79, an interrupt controller (INTC). 
The operation of the microprocessor 61 will be briefly described 
hereinafter. When an address of the processing program stored in the ROM 
72 is designated by the PC 75, and an instruction read out from the ROM 72 
is decoded, this instruction is executed. The FLAG register 76 stores 
carry and borrow states of results of a calculation operation. The 
calculation results are stored in the ACC 77 or in the RAM 73 by an 
instruction through the ACC 77. The STACK 78 designates a depth of a 
subroutine, and stores a return address of a main routine and is used as a 
content save storage for the PC 75 in an interrupt mode. When an internal 
interrupt request signal or an interrupt signal at an external terminal 
(INT) is supplied to the INTC 79, the INTC 79 interrupts the instruction 
being executed, and executes an interrupt processing. During such an 
interrupt processing, the content of the PC 75 is temporarily saved in the 
STACK 78, and an address jumps to a specific address for executing the 
interrupt processing so as to complete the interrupt processing program. 
Thereafter the flow returns to the main program. 
FIG. 14 shows a general flow chart of a normal copying apparatus. Note that 
an initial check of the step S2 means a routine for checking whether or 
not the copying apparatus is in the copying mode, for example, whether or 
not the heat rollers are at a fixing temperature. After executing the 
initial check, if YES in this step, the routine advances to a copying 
standby state step S3. This step S3 is for waiting until the number of 
copying paper sheets is preset and a copying switch is turned on and then 
the copying operation starts. When the copying operation starts, the 
copying processes comprising the charging, exposing, transferring, 
discharging and fixing operations are sequentially performed to accomplish 
the copying operation, and are repeated until the preset number of copying 
paper sheets are copied. In addition, during the copying operation, 
malfunction such as a paper jam is also checked for. 
Furthermore, the control during the copying operation will now be described 
with reference to the flow chart shown in FIGS. 15A and 15B. When the 
copying operation starts, the flow of FIG. 15A advances to step S1. In 
step S1, the blade solenoid 67, the motor 21, the discharging lamp 15, and 
the high voltage source 66 (for the chargers 13 and 16) are respectively 
turned on, and then the routine advances to step S2. In step S2, the 
microprocessor 61 determines, in accordance with signals from the original 
rest switches 56 and 57, whether or not the original rest 3 is positioned 
at its start position. If NO in step S2, the operation advances to step 
S3. In step S3, a control signal is supplied to the original rest clutch 
36 so as to move the original rest 3 in the backward direction, and the 
operation advances to step S4. On the other hand, if YES in step S2, the 
flow jumps to step S4. In step S4, the original rest 3 is moved to the 
original rest start position, and when both the original rest switches 56 
and 57 are turned on to indicate the original rest start position, the 
routine advances to step S5. In step S5, a control signal is supplied to 
the paper feed roller solenoid 47 so as to rotate the paper feed roller 10 
and the exposure lamp 4 is turned on, and then the operation advances to 
step S6. In step S6, the control signal is supplied to the original rest 
clutch 36, thereby moving the original rest 3 in the forward direction, 
and the operation advances to step S7. In step S7, the high voltage source 
(the charger 6) is turned on, and the operation advances to step S8. In 
step S8, the microprocessor 61 determines whether or not the aligning 
roller is positioned at its start position. If YES in step S8, the 
operation advances to step S10 of FIG. 15B. In step S10, a control signal 
is supplied to the aligning roller solenoid 65 so as to rotate the 
aligning rollers 11a, 11b, and the operation advances to step S11. In step 
S11, the microprocessor 61 determines whether or not the original rest 3 
is moved to the original rest limit position which is detected when only 
the original rest switch 57 is turned on. If YES in step S11, the 
operation advances to step S12. In step S12, the high voltage source 64 is 
turned off and the operation advances to step S13. In step S13, a control 
signal is supplied to the original rest clutch 36 so as to move the 
original rest 3 in the backward direction, and the operation advances to 
step S14. In step S14, the exposure lamp 4 is turned off and the operation 
advances to step S15. In step S15, the microprocessor 61 determines 
whether or not the original rest 3 is moved to the home position which is 
detected when the orignal rest switch 56 is turned on. If YES in step S15, 
the operation advances to step S16. In step S16, the microprocessor 61 
determines whether or not the preset number of copy sheets has been 
produced. If NO in step S16, the operation returns to step S4 of FIG. 15A 
and the above-mentioned copying operation is repeated. If YES in step S16, 
the routine advances to step S17. In step S17, a control signal is 
supplied to the original rest clutch 36 so as to stop the original rest 3 
at the home position, and the operation advances to step S18. In step S18, 
the microprocessor determines, in accordance with the signal supplied from 
the paper discharge switch 23, whether or not the copied paper sheet P has 
been completely discharged. If YES in step S18, the operation advances to 
step S19. In step S19, the high voltage source 66, the discharging lamp 
15, the motor 21 and the blade solenoid 67 are respectively turned off, 
thereby ending the copying operation, and the copying apparatus is set in 
the copying standby state of step S3 of FIG. 14. 
The interrupt operation of the copying apparatus is performed by using an 
internal interrupt request generated within the microprocessor 61. This 
interrupt processing is preset to be repeatedly performed at every 
predetermined period. This interrupt processing will be described with 
reference to FIG. 16. A main program among the programs stored in the ROM 
72 is executed upon energization of the copying apparatus. When the INTC 
79 is set to generate an internal interrupt every 12 msec after the copy 
operation is started, the main program is temporarily interrupted after a 
lapse of 12 msec since the copy operation was started. When the interrupt 
program is completed, the main program is accessed again. In addition, 
when a period of 12 msec has elapsed, i.e., when a period of 24 msec has 
elapsed since the copy operation was started, the interrupt program is 
executed. 
As described with reference to FIG. 14, malfunctions such as paper jamming 
are checked for by the microprocessor 61 during the copy operation. Paper 
jam detection will be described hereinafter. The paper jam check is 
performed by an interrupt program which is repeatedly executed at every 
predetermined period. The paper jam detection will be described with 
reference to the flow chart in FIGS. 17A, 17B. Steps S1 to S4, S5 to S8 
and S9 to S11 perform different types of paper jam detection, 
respectively. Steps S1 to S4 of FIG. 17A check for a malfunction or an 
error of a type wherein the feed switch 22 is not turned on within a 
predetermined time T1 after the aligning rollers 11a, 11b are rotated to 
feed the sheet P. More particularly, when an interrupt period is given to 
be t, and the microprocessor detects in step S2 that the aligning roller 
solenoid 65 is kept on after the ON operation of the feed switch 22 is 
detected in step S1, a timer set in the RAM 73 is incremeted by one (the 
initial value of the timer is zero) in step S3. Since the interrupt is 
generated at every interrupt period t, a given address of the RAM 73 can 
serve as a timer. The microprocessor checks in step S4 whether or not the 
count of the timer exceeds T1/t. If YES in step S4, i.e., when the feed 
switch 22 is kept on for over the time T1 after the aligning rollers 11a, 
11b are rotated, error processing is executed. Steps 5 to 8 of FIG. 17B 
represent an error check of a type wherein the leading edge of the sheet P 
is not detected by the paper discharge switch 23 within a predetermined 
time T2 after the aligning rollers 11a, 11b are rotated to feed the sheet 
P. For example, the sheet P is not properly separated from the 
photosensitive drum 2, or the sheet P is not properly supplied to the heat 
rollers 18a, 18b. More particularly, a timer set in the RAM 73 monitors 
the ON operation of the paper discharge switch 23 in step S6 after the 
aligning roller solenoid 65 is turned on in step S5 in the same manner as 
in steps S1 to S4. The microcomputer checks in step S8 whether or not the 
count of the timer exceeds T2/t. If YES in step S8, error processing is 
executed. Steps S9 to S11 represent an error check of a type wherein the 
paper discharge switch 23 is not turned off within a predetermined time T3 
after it was turned on, i.e., jamming has occurred in the vicinity of the 
paper discharge switch 23 and the sheet cannot be discharged. More 
particularly, when steps S5 to S8 are properly executed, the paper 
discharge switch 23 is turned on. The microprocessor detects in step S9 
that the paper discharge switch 23 is turned on, a timer set in the RAM 73 
monitors the ON time of the paper discharge switch 23 in the same manner 
as in steps S1 to S4. The microprocessor checks in step S11 whether or not 
the count of the timer exceeds T3/t. If YES in step S11, error processing 
is performed. 
Subsequently, the error processing described above will be described with 
reference to the flow chart of FIG. 18. In step S1, the copying operation 
is interrupted by interrupting the copying processes such as the charging, 
exposing, transferring, and peeling operations, and the operation advances 
to step S2. In step S2, a control signal is supplied to the original rest 
clutch 36 so as to move the original rest 3 in the forward direction, and 
the operation advances to step S3. In step S3, the microprocessor 61 
determines whether or not the original rest 3 has moved to the original 
rest limit position which is detected when only the original rest switch 
57 is turned on. If YES in step S3, the operation advances to step S4. In 
step S4, a control signal is supplied to the original rest clutch 36 so as 
to stop the original rest 3, and the operation advances to step S5. In 
step S5, the motor 21 is turned off, and the operation advances to step 
S6. In step S6, the blade solenoid 67 is turned off, thereby separating 
the blade of the cleaner 14 from the photosensitive drum 2, and the 
operation advances to step S7. In step S7, display of the paper jam is 
made and all other operations are stopped. 
By performing this error processing, the original rest 3 is stopped at the 
original rest limit position (in the state of FIG. 11). This is the stop 
position in a direction along which the original rest 3 is naturally 
moved, when the upper unit 1a is opened in a direction indicated by the 
arrow c, as shown in FIG. 2. Therefore, the operator need not move the 
original rest 3 before he removes the jamming paper sheet, every time the 
paper jam occurs. Thus, if the operator opens the upper unit 1a for 
removing the jamming paper sheet, the original rest 3 has been fixed to 
its limit position and cannot be accidentally moved. Therefore, impact due 
to movement of the original rest 3 is prevented, so that undesirable 
damage to the original rest 3 or the housing 1 does not occur. 
In the above embodiment, an electronic copying apparatus of original rest 
moving type is described, but the present invention is not limited to this 
and the present invention can be adopted in an electronic copying 
apparatus of fixed original type. In other words, the original rest is 
fixed in the housing 1 and an optical system such as an exposure lamp is 
provided on a moving table. 
Furthermore, in the above embodiment, the present invention is adopted in 
an electronic copying apparatus, but the present invention is not limited 
to this. For example, the present invention can be adopted in an image 
forming apparatus such as a color copying machine. 
Another embodiment of the present invention will be described with 
reference to FIGS. 19 to 22 hereinafter. In the second embodiment, when a 
toner empty state is detected as a malfunction, an original rest 3 is 
automatically stopped at a position at which it does not cover a toner 
replenishment port. The other configuration is the same as that of the 
first embodiment shown in FIG. 2, and only a portion of a developer 7 is 
shown for simplicity. 
FIG. 19 schematically shows a configuration of the developer 7. Reference 
numeral 7-1 denotes a developer housing which stores a developing roller 
(not shown). A toner hopper 7-2 for storing toner as a developing agent is 
mounted at an upper portion of a rear end of the housing 7-1. Toner stored 
in the toner hopper 7-2 is supplied by a toner replenishment mechanism 
(not shown) in a predetermined amount, as the toner is consumed by the 
developing operation. Therefore, the toner hopper 7-2 has an opening as a 
toner replenishment port 7-3. A cap (to be referred to as a hopper cover 
hereinafter) 7-4 is pivotally mounted on the toner replenishment port 7-3 
to be freely opened/closed. The toner replenishment port 7-3 and the 
hopper cover 7-4 are exposed from an upper surface of a housing 1 
corresponding to a travelling path of the original rest 3, as shown in 
FIG. 20. When there is no more toner stored in the toner hopper 7-2, the 
operator opens the hopper cover 7-4 from the upper portion out of the 
housing 1 and can supply toner into the toner hopper 7-2. On the other 
hand, a curved arm 7-5 shown in FIG. 19 is mounted at one end portion of a 
lower surface of the hopper cover 7-4. In addition, a magnet 7-6 is 
mounted at a free end of the arm 7-5. A read switch 7-7 is provided at a 
portion opposite the magnet 7-6 mounted on the free end of the arm 7-5. 
The read switch 7-7 is mounted on a printed circuit board 7-8. Therefore, 
when the hopper cover 7-4 is opened, the magnet 7-6 is separated from the 
read switch 7-7 and the read switch 7-7 is turned off, thereby indicating 
that the hopper cover 7-4 is opened. On the printed circuit board 7-8, a 
read switch 7-9 for detecting the empty state of the toner hopper 7-2 is 
mountd. Furthermore, a plate arm 7-11 is provided in the toner hopper 7-2 
corresponding to the read switch 7-9 and is pivoted through a 
predetermined angle about a shaft 7-10 while a motor 21 is rotated by a 
mechanism (not shown). A magnet 7-12 is mounted at a free end of the arm 
7-11. Therefore, the read switch 7-9 is turned on/off when the magnet 7-12 
is brought into contact or separated therefrom upon pivotal movement of 
the arm 7-11. When toner exists between the arm 7-11 and a side surface of 
the toner hopper 7-2, that is, when toner replenishment is not necessary, 
the magnet 7-12 mounted at the free end of the arm 7-11 is spaced apart 
from the read switch 7-9. Therefore, when the read switch 7-9 is turned 
on, it is confirmed that toner replenishment is needed. 
FIG. 21 schematically shows an overall control circuit. Note that the same 
reference numerals as in FIG. 12 denote the same parts in FIG. 21. 
Corresponding input signals are supplied to a microprocessor 61 through an 
interface circuit 62 from a paper feed siwtch 22, a paper discharging 
switch 23, original rest switches 56 and 57, a read switch 7-7 (to be 
referred to a hopper cover switch hereinafter) and the read switch 7-9 (to 
be referred to a toner empty switch hereinafter). The microprocessor 61 
determines these input signals and processes them so as to generate 
various control signals through an interface circuit 63 in accordance with 
a predetermined program stored therein. 
The operation of this embodiment shown in FIGS. 19 to 21 will be described 
with reference to a flow chart of FIG. 22. Steps S1 (copying start) to S15 
(determination that the preset number of copying operations has been 
performed) are the same as those of the first embodiment as described in 
FIGS. 15A and 15B, and so a description thereof starts from step S16. 
In FIG. 22, when the microprocessor 61 determines in step S15 that the 
preset number of copying operations has been performed, the operation 
advances to step S16. In step S16, the microprocessor 61 determines 
whether or not the toner empty switch 7-9 is turned on. If YES in step 
S16, the operation advances to step S17. In step S17, the original rest 3 
is moved in the backward direction until the rest 3 is detected at the 
original rest start position. When the original rest start position is 
detected, the operation advances to step S18. In addition, if NO in step 
S16, toner replenishment is not necessary and so the routine jumps to step 
S18. In step S18, a control signal is supplied to an original rest clutch 
36 so as to stop the original rest 3, and the operation advances to step 
S19. In step S19, the microprocessor 61 determines, in accordance with a 
signal from the paper discharing switch 23, whether or not a copied paper 
sheet P is discharged. If YES in step S19, the operation advances to step 
S20. In step S20, a high voltage source 66, a discharging lamp 15, a motor 
21, and a blade solenoid 67 are respectively turned off, thereby ending 
the copying operation. Then, the copying apparatus is in the same standby 
state as in FIG. 15B. 
By performing the above-mentioned control, when the toner must be 
replenished, the original rest 3 stops at the original rest start 
position, that is, the position shown in FIG. 20. After completing the 
copying operation, the copying apparatus is in the state wherein the 
hopper cover 7-4 can be freely opened/closed in a direction indicated by 
the arrow d in FIG. 20. Therefore, when the toner is to be supplied, the 
operator need not manually move the original rest 3 unlike in a 
conventional case. Furthermore, since the original rest 3 stops at a 
position different from a normal stop position, the fact that the 
malfunction has occured can be signalled to the operator.