Image forming apparatus and image forming method

An image forming apparatus selects and combines necessary image sections from a plurality of documents thereby to obtain a combined image on one sheet of paper. The image forming apparatus is provided with an optical scanning system for exposing/scanning a document in relative movement therewith, a lever for setting a reference position to divide the document into a plurality of sections in the scanning direction of the document, a transfer belt for holding an image of each section at every exposure/scanning time, and a transfer charger for transferring the image held by the transfer belt to a paper, each of which is controlled so that the images of a plurality of the sections are combined and transferred at one time to the paper.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention generally relates to an image forming apparatus such as a 
copying machine or the like, and more particularly, to an image forming 
apparatus having a function to obtain a combined image from a plurality of 
documents. 
2. Description of Related Art 
As one example of performances executed by a copying machine, there is an 
editing work, whereby necessary parts are extracted from a plurality of 
documents thereby to edit one image. Editing becomes necessary to obtain a 
combined image, for instance, when the using copying machine is equipped 
with various kinds of optional functions. Conventionally, in such case as 
above to obtain the combined image, copies of images from a plurality of 
documents are cut and bonded on a board sheet, or a desired image is 
extracted in a combining mode. 
However, it takes much trouble to copy the documents once, cut and bond the 
copied images on the board sheet and then copy the board sheet again, 
resulting in a long time of work and degradation of the image quality 
every time copying is performed. 
On the other hand, editing according to the combining mode can prevent 
degradation of the image quality, but requires additional devices 
corresponding to the desired image. The manipulation of the apparatus 
becomes therefore complicated. At the same time, the structure and cost of 
the apparatus is increased. For example, an editor and a combining device 
are necessitated to effect the combining mode in a general mono-color 
copying machine. The editor is used to take out necessary parts of the 
document by inputting coordinates of four points in a scanning direction 
of the document and in a direction orthogonal to the scanning direction 
and taking out an image of the part enclosed by the four points or the 
part except the enclosed part. It is troublesome to input the coordinates. 
The combining device circulates a paper to which an image is once 
transferred and fixed so as to transfer another image again to the paper. 
The combining device becomes inevitably bulky in structure. Moreover, 
although a full-color copying machine using an intermediate transfer body 
does not require the combining device since a combined image can be formed 
on the intermediate transfer body, the editor is indispensable to take out 
the necessary image, thereby giving rise to the same problems as described 
above. 
SUMMARY OF THE INVENTION 
An image forming apparatus according to this invention is provided with 
scanning means for exposing/scanning a document in relative movement with 
the document, indicating means for indicating a reference line to divide 
the document in a plurality of sections in the scanning direction of the 
scanning means, image holding means for holding an image of the scanned 
document, transfer means for transferring the held image to a transfer 
object, and control means for controlling the scanning means, image 
holding means and transfer means so as to transfer a plurality of images 
held by the holding means to the transfer object all at once. A lever 
moving in the scanning direction is used for the indicating means to 
indicate the image section. 
In the combining mode of this invention, when the lever is moved to a 
desired position in the scanning direction, a section from a front end of 
the image to the position of the lever is set as a first exposing/scanning 
area of the document and the image in the set first area is held by the 
image holding means. Thereafter, a section from the position of the lever 
to a rear end of the image is set as a second exposing/scanning area of 
the document, and the image in the set second area is held by the image 
holding means. An image obtained by combining the two images at the 
boundary where the lever is positioned is held by the image holding means 
and transferred to the transfer object, e.g., a copying paper or the like 
by the transfer means. 
An object of this invention is to provide an image forming apparatus 
capable of combining images through simple manipulation. 
Another object of this invention is to provide an image forming apparatus 
capable of combining images in a simple structure. 
The above and further objects and features of the invention will more fully 
be apparent from the following detailed description with accompanying 
drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
This invention will be discussed in detail taken in conjunction with 
preferred embodiments thereof with referring to the accompanying drawings. 
Referring to FIG. 1 showing an analog full-color copying machine 1 
according to one embodiment of the present invention, a photosensitive 
drum 3 is provided relatively upper leftward of the center of the copying 
machine 1 to be rotatable in a clockwise direction (direction of an arrow 
M1). An electrostatic charger 4, an editing eraser 5, developers 6-9, a 
transfer belt 11, a cleaning device 22 and a main eraser 23 are mounted in 
the periphery of the photosensitive drum 3. 
A photosensitive layer is formed on the surface of the photosensitive drum 
3. When the photosensitive drum 3 passes the main eraser 23 and 
electrostatic charger 4, the surface of the drum is uniformly charged and 
exposed to form a latent image by an optical system 27 including an 
optical scanning device. The editing eraser 5 is utilized for forming a 
full-color image, and comprised of an LED array having many LEDs aligned 
in a holder provided along an axial direction of the photosensitive drum 
3. The editing eraser 5 is capable of partly deleting the latent image on 
the photosensitive drum 3. The developers 6-9 contain developing materials 
of respective mixture of toners, namely, yellow (Y), mazenta (M), cyan 
(C), black (CK) and carriers. The concentration of each toner is 
controlled by a toner concentration sensor 71y, 71m, 71c or 71k. It is to 
be noted that the developers 6-9 are not necessarily fixedly mounted on 
the periphery of the photosensitive drum 3, but may be formed integrally 
into one body to be movable in an up-and-down direction. That is, it is 
enough that toners of different colors can be selectively supplied to the 
photosensitive drum 3. 
The transfer belt 11 temporarily holds a toner image developed onto the 
photosensitive drum 3 by the developers 6-9 before the toner image is 
transferred to a paper P (secondary transfer). The transfer belt 11 is 
hung around a plurality of rollers 12-16 and kept always in contact with 
the photosensitive drum 3. Moreover, the transfer belt 11 is rotatable in 
a counterclockwise direction (direction of an arrow M4). A transfer 
charger 17 is disposed inside the transfer belt 11 to transfer the toner 
image from the photosensitive drum 3 onto the transfer belt 11 (primary 
transfer). Outside the transfer belt 11, there are provided a transfer 
charger 20 for the secondary transfer, a separation charger 21 for 
separating the paper P from the transfer belt 11 and a belt cleaner 19 
having a fur brush 19a to clean the outer surface of the transfer belt 11. 
The fur brush 19a is selectively brought in pressed contact with (at the 
cleaning time) and detached from the transfer belt 11. The angular 
position of the transfer belt 11 during rotation is known by a belt mark 
11a. Between rollers 15 and 16, a mark sensor 72 for detecting the angular 
position of the transfer belt 11 during rotation is fixedly mounted. 
A document glass 28 is placed on the upper surface of the copying machine 
1. A document size detecting device 101 which is built in at the inner 
side of the copying machine 1 immediately below the document glass 28 
moves in a manner not to hinder scanning to detect the size of a document 
D. 
A simultaneous lever 102 is movable along the moving direction of a scanner 
30 at the front side of the upper surface of the document glass 28. An 
image section to be scanned in the combining copy mode which will be 
described later is set by the simultaneous lever 102. The simultaneous 
lever 102 interlocks with a simultaneous switch 103 which is provided 
confronting to the simultaneous lever 102 with the document glass 28 
sandwiched therebetween. The position of the simultaneous switch 103 is 
detected at a pre-scanning time in the combining copy mode, according to 
which the combining copy mode is executed. 
The optical system 27 in the upper part of the copying machine 1 is 
constituted by the scanner 30 which is reciprocable in directions of an 
arrow M5 (forwarding direction) and an arrow M6 (returning direction) 
below the document glass 28, a main lens whose position is adjusted in 
correspondence to the copying magnification, a filter selecting device 36 
for the color separation exposure, a fixed mirror 37 which guides a 
scanning light L reflected by a mirror mounted in the filter selecting 
device 36 to the photosensitive drum 3 and a color image sensor 38 which 
receives the scanning light L having passed through the mirror of the 
filter selecting device 36, etc. The optical system 27 scans the document 
D when the scanner 30 moves in the forwarding direction, thereby to expose 
the photosensitive drum 3. 
The scanner 30 is comprised of a first slider 31 with an exposure lamp 33, 
a mirror 34 and a detecting piece 39 and, a second slider 32 with mirrors 
35a, 35b. During the scanning time of the document D, the first slider 31 
is forwarded at a speed V/n (V is a peripheral velocity of the 
photosensitive drum 3 and n is the copying magnification), while the 
second slider 32 is driven forward by a scan motor 29 at a speed V/2n. A 
home position which is the stopping position of the scanner 30 is detected 
when a home switch 74 constituted by a photosensor is shut off by the 
detecting piece 39 and turned ON. The filter selecting device 36 has a 
half mirror 36ND (the ratio of the transmission and reflection is 6:4) and 
three filter mirrors 36YB, 36MG, 36CR arranged radially around a shaft 36a 
with 90 degrees from each other. The mirrors are selectively switched 
through rotation. Each of the filter mirrors 36YB, 36MG, 36CR is a unit of 
a mirror and a filter obtained by vapor-depositing a color separation 
filter of blue (B), green (G), red (R) to a mirror surface, and is used 
corresponding to the respective color of toners, i.e., Y, M, C. 
During exposing and scanning for formation of an image, a reflecting 
surface of the selected mirror is so positioned as to incline 
approximately 10 degrees in the clockwise direction to a vertical surface, 
thereby the scanning light L is guided to an exposing point of the 
photosensitive drum 3. Moreover, during preparatory scanning to read the 
image of the document D prior to the above exposing and scanning for image 
formation, the half mirror 36ND is selected and positioned to be 
orthogonal to a direction of incidence of the scanning light L so as to 
improve the image forming ability of the color image sensor 38. A rotating 
position detecting sensor 77 determines the home position of the filter 
selecting device 36. FIG. 1 illustrates the state where the filter mirror 
36CR is selected and positioned. In the following description, the half 
mirror 36ND and filter mirrors 36YB, 36MG, 36CR will sometimes be denoted 
respectively as an ND filter, a B filter, a G filter, an R filter in 
relation to the color separation characteristics thereof. The color image 
sensor 38 is formed of three arrays of many photodetecting elements 
aligned in a main scanning direction. The R, G, B filters are provided in 
the first, second and third arrays, respectively. One photodetecting 
element corresponds to one pixel of the image of the document. From each 
photodetecting element, a photoelectric conversion signal SO corresponding 
to the intensity of the reflecting light to one color of pixels is fed to 
an image processing part 100 as a document information. 
Meanwhile, in the lower part of the copying machine 1, there are provided 
an upper paper cassette 42 and a lower paper cassette 43 where papers P 
are accommodated. A paper feed port 41 is opened at the left side face of 
the copying machine 1 through which the paper P is manually fed by opening 
a door 41a. These paper cassettes 42, 43 and paper feed port 41 are 
alternatively used. The paper cassettes 42, 43 are equipped with pickup 
rollers 44, 45 for taking out the papers P one by one, paper size sensors 
81, 82 to detect the size of the papers P and paper empty sensors 83, 84 
to detect the shortage of the papers P, respectively. A sensor 87 provided 
at the paper feed port 41 detects when the paper P is inserted. 
The paper P drawn out from the paper cassette 42 is transferred to a timing 
roller 46 by a paper feed roller 47, and the paper P drawn out from the 
paper cassette 43 is guided by the paper feed rollers 48, 47 to the timing 
roller 46. The paper P stands by at the timing roller 46. On the other 
hand, the paper inserted through the paper feed port 41 is carried to the 
timing roller 46 by a feed roller 49. The presence or absence of the paper 
P at a feed route R1 between the paper feed roller 47 and timing roller 46 
is detected by a paper sensor 85 provided in the vicinity of the paper 
feed roller 47. Moreover, a timing sensor 86 in the vicinity of the timing 
roller 46 detects a front end of the passing paper P. The waiting paper P 
is transported through rotation of the timing roller 46 in synchronism 
with the transfer belt 11, and a toner image is transferred to the paper P 
from the transfer belt 11 at the transfer position (secondary transfer). 
Thereafter, the paper P is sent to a fixing unit 51 by a conveyor belt 50 
of the straight length corresponding to papers of A4 size. 
The fixing unit 51 is constituted by an upper roller 52 with two heater 
lamps 54, 55, a lower roller 53 with one heater lamp 56 and a temperature 
sensor 91 formed of a thermister arranged in the vicinity of the upper 
roller 52, and the like. The toner image is melted and fixed to the paper 
P at the fixing unit 51. The paper P is, after a desired copying image is 
formed thereon through fixing of the toner image, sent to a sorter 2 by a 
discharger roller 57 which has a discharge sensor 88 arranged in the 
vicinity thereof to detect a rear end of the passing paper P, to be 
discharged to a storing tray 61 or a sorting bin 62. 
In FIG. 1, references 24, 25 and 26 respectively represent a main motor for 
driving each part related mainly to the supply and conveyance of the paper 
P, a PC motor for driving the photosensitive drum 3 and transfer belt 11 
or the like, and a cooling fan. 
In the copying machine 1 of the above-described structure, it is possible 
to obtain a mono-color copying image by toners of a single color Y, M, C 
or BK, a synthetic mono-color copying image R (Y and M), G(Y and C) or B(M 
and C) obtained by overlapping toner images of two different colors, among 
the three primary colors Y, M, C, and a full-color copying image obtained 
by overlapping toner images of three primary colors. 
In order to form the mono-color image and synthetic mono-color image, the 
half mirror 36ND is used to expose and scan the document D and a latent 
image formed on the photosensitive drum 3 is developed by one of the 
developers 6-9 other corresponding to the designated color, and the toner 
image is transferred to the transfer belt 11. Further, for obtaining the 
synthetic mono-color copying image, the same document D is exposed and 
scanned again by the half mirror 35ND, and the toner image developed by a 
different developer 6-9 than the previous one is transferred onto the 
transfer belt 11, whereby the toner images of two colors are overlapped on 
the transfer belt 11. On the other hand, in order to form the full-color 
image, toners of four colors in which BK being added to Y, M, C are 
sequentially used to enhance the reproducibility or reality of the black 
portion of the image. In other words, the same document D is exposed and 
scanned four times. The B, G, R, ND filters and developers 6-9 are 
selectively switched every scanning time and the latent images subjected 
to color separation from the document D are formed and developed on the 
photosensitive drum 3. The toner images are sequentially transferred to 
the transfer belt 11, and overlapped one after another thereon. 
It is necessary to transfer the toner images onto the same position of the 
transfer belt 11 when the toner images are overlapped (referred to as a 
multiple transfer hereinafter). Therefore, according to the copying 
machine 1 of the embodiment, it is so arranged that the scanner 30 is 
started to be driven when the belt mark 11a of the transfer belt 11 is 
detected, thereby controlling the starting timing of formation of the 
latent images on the photosensitive drum 3. 
When the full-color image is formed, the image of the document D is 
distinguished between a color image part including colored portions and a 
monochrome image part composed only of uncolored portions at the 
preparatory scanning. Accordingly, when images of each toner, Y, M, C are 
formed, the latent image corresponding to the monochrome image part is 
erased by the editing eraser 5 prior to the development. When the image of 
BK toner is formed, in contrast, the latent image corresponding to the 
color image part is erased before development. That is, the color image 
part is reproduced by the multiple transfer of each toner, Y, M, C and the 
monochrome image part is reproduced by only the BK toner. A clear copying 
image can be obtained in this manner as above without minute shift of 
colors from a character which is generally expressed in black or an image 
with small line width such as a line drawing, etc. and at the same time, 
it becomes possible to reproduce the natural color of a multi-color image, 
for example, a color picture. 
An operating panel is mounted at the front side on the upper surface of the 
copying machine 1. FIG. 2 is a plan view of the layout of the operating 
panel. A print switch 200 is provided at the lower right part of the 
operating panel to start copying. A clear spot key 203, an interruption 
key 204 and a ten key 202 are at the left side of the print switch 200. 
The ten key 202 is used to input various kinds of information, e.g., the 
number of papers to be copied and the like. An LED 201 of seven segments 
is provided at the upper portion of the print switch 200 to indicate the 
number of papers in copying progress, with an LED 207 of seven segments 
being provided at the belt side to indicate the copying magnification. 
Besides, an up key 205 and a down key 206 for setting the magnification, 
an automatic exposure key 209, a manual up key 208 and manual down key 210 
for manually changing the exposure amount, an exposure level indicating 
LED 211 and an automatic exposure selection indicating LED 222 are 
provided at the upper portion of the ten key 202. 
A mode selection key and a mode indicating LED are mounted at the left side 
of the operating panel. Concretely, there are a selection key 228 to 
select a monochrome copy mode, an indicating LED 230 to indicate when the 
monochrome copy mode is selected, a selection key 229 t select a 
full-color copy mode, an indicating LED 231 to indicate the selection of 
the full-color copy mode, a document selection button 232 to select a 
one-face or booktype document, a copy mode selection button 233 to set a 
one-face or a synthetic copy mode and an indicating part 234. If the 
combining copy mode is desired, the document selection button 232 should 
be pressed to select a one-face and the copy mode selection button 233 is 
switched to select combining the copy mode. Consequently, a copy combining 
two documents can be obtained. 
FIG. 3 is a block diagram showing the structure of a control system to 
control the copying machine 1. The copying machine 1 is controlled by a 
microcomputer (referred to as a CPU hereinafter) 300. Signals from a mark 
sensor 72, print switch 200, ten key 202, document selection button 232, 
copy mode selection button 233 and the other key inputs and various kinds 
of detecting signals are input to the CPU 300. In response to the input 
signals, the CPU 300 generates an output signal to the transfer chargers 
17, 20, a clutch 46a of the timing roller 46 and the other elements and 
devices, thereby to control the same. 
The copying machine 1 operates in the manner as follows. 
Referring to a flow chart of FIG. 4 showing a main routine of the CPU 300, 
when the power switch is turned ON to start the program, an internal RAM 
of the CPU 300 is cleared and a register and a timer, etc. are initialized 
(step #11). The inner timer is set to determine the length of one routine 
of the CPU 300 (step #12). Then, signals corresponding to key inputs 
through the operating panel and various sensors are processed (step #13), 
and necessary procedures for steps #14-#22 are performed in accordance 
with the result of step #13. 
First, the scanning process at the scanning time and returning time of the 
scanner 30 is carried out (step #14). A grid voltage of the electrostatic 
charger 4 and the ON/OFF timing of the outputs thereof are controlled in 
the charging process in order to charge the photosensitive drum 3 (step 
#15). An output voltage of the exposure lamp 33 and the lighting timing 
thereof are controlled to expose and scan a document in the exposing 
process (step #16). Then, the developer 6-9 of the color designated in the 
developing process is driven or stopped, toners are supplied and the 
shortage of toners is detected, etc. (step #17). After completing the 
development, the transfer charger 17 is controlled to be turned ON/OFF so 
that a toner image on the photosensitive drum 3 is transferred onto the 
transfer belt 11 in the primary transfer process (step #18). Then, the 
transfer charger 20 is controlled to be turned ON/OFF so that the toner 
image transferred onto the transfer belt 11 is transferred to the paper P 
in the secondary transfer process (step #19). 
The pickup roller 44, 45 or 49 of the paper cassette 42, 43 or paper feed 
port 41 is alternatively selected in the paper feeding process, thereby 
the paper P is supplied (step #20). The paper P is sequentially 
transported through ON/OFF control of the timing roller 46, paper feed 
rollers 47, 48 and conveyor belt 50, etc. in the transporting process 
(step #21). Subsequently, procedures necessary for copying other than 
those in the foregoing steps, for example, cleaning process, side erasing 
process, main erasing process and the like are conducted (step #22). Other 
procedures not directly related to the copy operation, such as temperature 
control of the fixing unit 51, display of LED on the operating panel and 
so on, are conducted (step #23). 
Thereafter, it is checked whether the inner timer is finished (step #24). 
The flow is not returned to the step #12 until the inner timer is 
complete. The procedures in the steps #12-#23 are repeated for a fixed 
term until the power supply is cut. 
Before the details of the aforementioned procedures, the setting time of 
the timer will be explained below. 
A time T0 is a time necessary for the transfer belt 11 to rotate one round. 
A time T1 is a time necessary for the scanner 30 to move from a front end 
of image to the position of simultaneous lever 102, and a time T2 is a 
time necessary for the scanner 30 to move from the position of 
simultaneous lever 102 to a rear end of image. Moreover, a timer T3 is 
required for the copying section to pass through each procedure. An 
equation T3=T1+T2 is held. Moreover, times t2, t3, t4, t5, t6 represent 
respectively moving times from the charging point to the exposing point, 
from the exposing point to the developing point, from the exposing point 
to the primary transfer point, from the primary transfer point to the 
secondary transfer point and a time expressed by t5 (moving time of the 
paper P from the timing roller 46 to the secondary transfer point). 
FIG. 5(a), (b) are flow charts showing the content of the scanning process 
in the step #14. In the first place, the value of the state counter 
(initial value 0) indicative of the controlling state is checked (step 
#101). When the state counter indicates 0, it is checked whether the print 
switch 200 is on-edge, namely, whether the print switch 200 is turned ON 
(step #102). In the case where the print switch 200 is on-edge, it is 
discriminated whether a combining copy mode is selected by pressing the 
document mode selection button 232 and copy mode selection button 233 
(step #103). When the combining copy mode is selected, a scan flag is set 
to 1, thereby starting pre-scanning (step #104). The pre-scanning is aimed 
to determine the time for the timer T1 through detection of the position 
of the simultaneous lever 102 by the simultaneous switch 103 in the 
combining mode. Then, the state counter is set to 1 (step #105). The flow 
is once returned to the main routine, and a procedure when the state 
counter is 1 is performed at a next routine. In the case where the print 
switch 200 is not on-edge in the step #102, nothing is processed, thereby 
returning the flow to the main routine. Moreover, if the combining copy 
mode is not selected in the step #103, general scanning process is carried 
out (step #106) to return the flow to the main routine. When the state 
counter shows 1, it is detected whether or not the simultaneous switch 103 
is on-edge, i.e., whether the scanner 30 passes the simultaneous lever 102 
(step #107). If the simultaneous switch 103 is not on-edge, the flow 
returns to the main routine. On the other hand, if the simultaneous switch 
103 is on-edge, the scan flag is reset to 0, thereby stopping the scanner 
30 (step #108) and setting the return flag to 1 to return the scanner 30 
(step #109). After the state counter is set to 2 (step #110), the flow is 
returned to the main routine once. Then, a procedure when the state 
counter is 2 is carried out at a next routine. When the state counter is 
2, the scanner 30 detects the home switch 74 to check whether the scanner 
30 is returned to the reference position (step #111). If the scanner 30 is 
not returned to the reference position, the flow is moved back to the main 
routine. And, if the scanner is returned to the reference position, the 
return flag is set to 0, stopping the pre-scanning (step #112). The copy 
flag is set to 1 (step #113) and the state counter is set to 3 (step 
#114). Thus, the flow goes back to the main routine. 
At a next routine, when the state counter is 3, the state of the copy flag 
and mark sensor 72 is checked (steps #115, #116). When the copy flag is 1 
and mark sensor 72 is on-edge, the scan flag is set to 1 to start scanning 
for the first sheet of the document (step #117). Thereafter, the state 
counter is set to 4 (step #118), with the flow once returning to the main 
routine. When the copy flag is 0 and the mark sensor 72 is not one-edge, 
nothing is conducted and the flow is returned to the main routine. When 
the state counter is 4, it is checked whether the scanner 30 has reached 
the scan end position (step #119). Although the flow moves to the main 
routine if the scanner 30 does not reach the scan end position, the scan 
flag is reset to 0 when the scanner 30 has reached the scan end position, 
with stopping the scanner 30 (step #120). Subsequently, the return flag is 
set to 1 so that the scanner 30 is moved back to the reference position 
(step #121). The state counter is set to 5 (step #122), when the flow is 
in turn returned to the main routine. At a next routine, a procedure when 
the state counter is 5 is performed. Specifically, when the state counter 
is 5, it is checked whether the home switch 74 is on-edge, i.e., whether 
the scanner 30 has reached the reference position (step #123). In the case 
where the scanner 30 has not reached the reference position, the flow is 
sent back to the main routine. When the scanner 30 has reached the 
reference position, the return a flag is reset to 0 to terminate returning 
of the scanner 30 (step #124). The area mode is checked as to whether or 
not it is A (step #125). The area mode A referred to above indicates a 
section from a front end of the image to the position of the simultaneous 
lever 102 of the two image sections divided in the combining mode, while 
the area mode B represents a section from the position of the simultaneous 
lever 102 to a rear end of the image. When the area mode is A, the state 
counter is set to 3 and the area B is scanned (step #126). On the 
contrary, if the area mode is not A, the state counter is reset to 0 (step 
#127) thereby to return the flow to the main routine. 
FIGS. 6(a), (b) are flow charts showing the content of the charging process 
in the step #15. The value of the state counter (initial value 0) 
indicating the controlling state is checked first (#201). When the state 
counter is 0, it is detected whether the copy flag is 1 or not, namely, 
whether copying is in progress or not (step #202). Then, when the copy 
flag is 1, it is checked whether the mark sensor 72 is on-edge, that is, 
whether the belt mark 11a of the transfer belt 11 has passed the mark 
sensor 72 (step #203). If it is detected that the belt mark 11a has passed 
the mark sensor 72, it is judged whether the combining mode is selected by 
the document mode selection button 232 and copy mode selection button 233 
(step #204). When the combining mode is selected, the area mode is set to 
A (step #205) and the state counter is set to 1 (step #206). Thereafter, 
the flow is returned to the main routine. A procedure when the state 
counter is 1 is conducted at a next step. If the copy flag is not 1 in the 
step #202 or the mark sensor 72 is not on-edge in the step #203, no 
treatment is performed and the flow is returned to the main routine. when 
the combining mode is not selected in the step #204, general charging 
process is carried out (step #207) and the flow is returned to the main 
routine. When the state counter is 1, the charging flag is set to 1 to 
start charging (step #208), with the timer T1 being set to determine the 
charging time of the first document (step #209) and the state counter 
being set to 2 (step #210). The flow is then returned to the main routine 
and at a next routine a procedure when the state counter is 2 is started. 
When the state counter is 2, the timer T1 is checked if it is finished 
(step #211). In the cases where the timer T1 is not finished, the flow 
goes back to the main routine. If the timer T1 is finished, the charging 
flag is rest to 0 to end charging (step #213). The state counter is set to 
3 (step #213) to return the flow to the main routine. 
At a next routine starting when the state counter is 3, the state of the 
copy flag as well as whether the mark sensor 72 is on-edge is checked 
(steps #214, #215). If the copy flag is 1 and the mark sensor 72 is 
on-edge, the area mode is set to B (step #216), the timer T1 is set to 
determine the starting timing of charging of the second document (step 
#217) and the state counter is set to 4 (step #218). Thereafter, the flow 
is moved once to the main routine. If the copy flag is 0 or if the mark 
sensor 72 is not on edge, the flow is directly returned to the main 
routine without anything performed. When the state counter is 4, it is 
checked whether the time T1 is finished (step #219). When the timer T1 is 
not finished, the flow goes to the main routine. If the timer T1 is 
finished, the charging flag is set to 1 thereby to start charging of the 
second document (step #220). The timer T2 is set to determine the charging 
time (step #221) and the state counter is set to 5 (step #222). Then, the 
flow is moved back to the main routine. At a next routine when the state 
counter is 5, the timer T2 is checked whether it is finished (step #223). 
Without the timer T2 finished, the flow is returned to the main routine. 
However, when the timer T2 is finished, the charging flag is reset to 0 to 
terminate charging (step #224). At the same time, the state counter is 
reset to 0 (step #225) to return the flow to the main routine. 
FIGS. 7(a), (b) are flow charts showing the content of the exposing process 
in the step #16. The value of the state counter (initial value 0) is first 
checked (step #301). If the state counter is 0, it is further checked 
whether the charging flag is 1, that is, whether the belt mark 11a is 
detected to start the charging process (step #302). In the case where the 
charging flag is not 1, the main routine is resumed. If the charging flag 
is 1, it is found whether the combining mode is selected (step #303). When 
the combining mode is selected, the timer t2 is set to determine the 
starting timing of exposure for the first document (step #304). In this 
case, the state counter is set to 1 (step #305), so that the flow is 
returned to the main routine. As a result, a procedure when the state 
counter is 1 is started at a next routine. If the combining mode is not 
selected in the step #303, general exposing process is carried out (step 
#306) and the flow is moved back to the main routine. When the state 
counter is 1, it is checked whether the timer t2 is terminated (step 
#307). If the timer t3 is not finished, the flow is returned to the main 
routine. In contrast, when the timer t2 is finished, the exposure flag is 
set to 1 thereby to start exposing (step #308). The timer T1 is set to set 
the exposing time (step #309) and then, the state counter is set to 2 
(step #310). Subsequently, the flow moves back to the main routine. A 
procedure when the state center indicates 2 is processed at a next 
routine. It is first checked whether the timer T1 is finished (step #311) 
when the state counter is 2. If the timer T1 is finished, the exposing 
flag is reset to 0 so as to end the exposure (step #312). The state 
counter is set to 3 (step #313), with the flow once returning to the main 
routine. Thereafter, a procedure when the state counter is 3 is started at 
a next routine. 
It is detected whether the charging flag is 1 when the state counter is 3 
(step #314). If the charging flag is not 1, the main routine comes back. 
However, if the charging flag is 1 and the second document is already 
started to be charged, the timer t2 is set to determine the starting 
timing of exposure of the second document (step #315). Then, after the 
state counter is set to 4 (step #316), the flow is returned to the main 
routine. It is checked whether the timer t2 is finished when the state 
counter is 4 (step #317). If the timer t2 is not finished, the flow is 
returned to the main routine. If the timer t2 is finished, the exposing 
flag is set to 1 thereby to start exposing of the second document (step 
#318). The timer T2 is set to determine the exposing time (step #319). The 
state counter is set to 5 (step #320) to return the flow to the main 
routine. Then, a procedure when the state counter indicates 5 is carried 
out at a next routine. If the state counter indicates 5, it is checked 
whether the timer T2 is finished (step #321). In the case whether the 
timer T2 is not finished, the flow goes back to the main routine. When the 
timer T2 is finished, the exposing flag is reset to 0 to terminate the 
exposure (step #322). Then, the state counter is reset to 0 (step #323) 
and the flow is returned to the main routine. 
FIGS. 8(a), (b) are flow charts showing the content of the developing 
process in the step #17. The value of the state counter (initial value 0) 
is first checked (step #401). If the state counter is 0, it is further 
checked whether the exposing flag is 1, that is, whether the belt mark 11a 
is detected to start the exposing process (step #402). In the case where 
the charging flag is not 1, the main routine is resumed. If the exposing 
flag is 1, it is found whether the combining mode is selected (step #403). 
When the combining mode is selected, the timer t3 is set to determine the 
starting timing of developing for the first document (step #404). In this 
case, the state counter is set to 1 (step #405), so that the flow is 
returned to the main routine. As a result, a procedure when the state 
counter is 1 is started at a next routine. If the combining mode is not 
selected in the step #403, general developing process is carried out (step 
#406) and the flow is moved back to the main routine. When the state 
counter is 1, it is checked whether the timer t3 is terminated (step 
#307). If the timer t3 is not finished, the flow is returned to the main 
routine. In contrast, when the timer t3 is finished, the developing flag 
is set to 1 thereby to start exposing (step #408). The timer T1 is set to 
set the developing time (step #409) and then, the state counter is set to 
2 (step #410). Subsequently, the flow moves back to the main routine. A 
procedure when the state center indicates 2 is processed at a next 
routine. It is first checked whether the timer T1 is finished (step #411) 
when the state counter is 2. If the timer T1 is finished, the developing 
flag is reset to 0 so as to end the developing (step #412). The state 
counter is set to 3 (step #413), with the flow once returning to the main 
routine. Thereafter, a procedure when the state counter is 3 is started at 
a next routine. 
It is detected whether the exposing flag is 1 when the state counter is 3 
(step #414). If the exposing flag is not 1, the main routine comes back. 
However, if the exposing flag is 1 and the second document is already 
started to be exposed, the timer t3 is set to determine the starting 
timing of developing of the second document (step #415). Then, after the 
state counter is set to 4 (step #416), the flow is returned to the main 
routine. It is checked whether the timer t3 is finished when the state 
counter is 4 (step #417). If the timer t3 is not finished, the flow is 
returned to the main routine. If the timer t3 is finished, the developing 
flag is set to 1 thereby to start developing of the second document (step 
#418). The timer T2 is set to determine the developing time (step #419). 
The state counter is set to 5 (step #420) to return the flow to the main 
routine. Then, a procedure when the state counter indicates 5 is carried 
out at a next routine. If the state counter indicates 5, it is checked 
whether the timer T2 is finished (step #421). In the case whether the 
timer T2 is not finished, the flow goes back to the main routine. When the 
timer T2 is finished, the developing flag is reset to 0 to terminate the 
developing (step #422). Then, the state counter is reset to 0 (step #423) 
and the flow is returned to the main routine. 
FIG. 9(a), (b) are flow charts showing the content of the primary transfer 
process in the step #18. The value of the state counter (initial value 0) 
is first checked (step #501). If the state counter is 0, it is further 
checked whether the exposing flag is 1, that is, whether the belt mark 11a 
is detected to start the exposing process (step #502). In the case where 
the exposing flag is not 1, the main routine is resumed. If the exposing 
flag is 1, it is found whether the combining mode is selected (step #503). 
When the combining mode is selected, the timer t4 is set to determine the 
starting timing of primary transfer for the first document (step #504). In 
this case, the state counter is set to 1 (step #505), so that the flow is 
returned to the main routine. As a result, a procedure when the state 
counter is 1 is started at a next routine. If the combining mode is not 
selected in the step #503, general primary transfer process is carried out 
(step #506) and the flow is moved back to the main routine. When the state 
counter is 1, it is checked whether the timer t4 is terminated (step 
#507). If the timer t4 is not finished, the flow is returned to the main 
routine. In contrast, when the timer t4 is finished, the primary transfer 
flag is set to 1 thereby to start primary transfer (step #508). The timer 
T1 is set to set the primary transfer time (step #509) and then, the state 
counter is set to 2 (step #510). Subsequently, the flow moves back to the 
main routine. A procedure when the state center indicates 2 is processed 
at a next routine. It is first checked whether the timer T1 is finished 
(step #511) when the state counter is 2. If the timer T1 is finished, the 
primary transfer flag is reset to 0 so as to end the primary transfer 
(step #512). The copy flag is reset to 0 so as to end the copying once 
(step #513). The state counter is set to 3 (step #514), with the flow once 
returning to the main routine. Thereafter, a procedure when the state 
counter is 3 is started at a next routine. 
It is detected whether the exposing flag is 1 when the state counter is 3 
(step #515). If the exposing flag is not 1, the main routine comes back. 
However, if the exposing flag is 1 and the second document is already 
started to be exposed, the timer t4 is set to determine the starting 
timing of primary transfer of the second document (step #516). Then, after 
the state counter is set to 4 (step #517), the flow is returned to the 
main routine. It is checked whether the timer t4 is finished when the 
state counter is 4 (step #518). If the timer t4 is not finished, the flow 
is returned to the main routine. If the timer t4 is finished, the primary 
transfer flag is set to 1 thereby to start primary transfer of the second 
document (step #519). The timer T2 is set to determine the primary 
transfer time (step #520). The state counter is set to 5 (step #521) to 
return the flow to the main routine. Then, a procedure when the state 
counter indicates 5 is carried out at a next routine. If the state counter 
indicates 5, it is checked whether the timer T2 is finished (step #522). 
In the case whether the timer T2 is not finished, the flow goes back to 
the main routine. When the timer T2 is finished, the primary transfer flag 
is reset to 0 to terminate the primary transfer (step #523). Then, the 
state counter is reset to 0 (step #524) and the flow is returned to the 
main routine. 
A flow chart of FIG. 10 shows the content of the secondary transfer process 
in the step #19. In the first place, the value of the state counter 
(initial value 0) is checked (step #601). Then, it is checked whether or 
not the first transfer flag is 1, i.e., whether the first transfer is 
started (step #602). When the first transfer flag is 1, it is detected 
whether the combining mode is selected (step #603). IF the combining mode 
is selected, it is checked whether the area mode is B, that is, whether it 
is a mode to be scanned by the scanner 30 from the position of the 
simultaneous switch 103 to the rear end of the image (step #604). When the 
area mode is B, the timer t5 is set to determine the starting timing of 
the secondary transfer (step #605), with the state counter being set to 1 
(step #606) and the flow returned to the main routine. If the first 
transfer flag is not 1, or if the area mode is not B, the flow is moved 
directly to the main routine. Moreover, if the combining mode is not 
selected, general secondary transfer is conducted (step #607) and the flow 
is brought back to the main routine. 
When the state counter is 1, at a next routine, the timer t5 is checked if 
it is finished (step #608). The flow is returned to the main routine if 
the timer t5 is not finished. On the other hand, the secondary transfer 
flag is set to 1 to start the secondary transfer when the timer t5 is 
finished (step #609). In this case, the timer T3 is set to decide the 
timer of the secondary transfer (step #610) and the state counter is set 
to 2 (step #611). Then, the flow is once returned to the main routine. 
According to a next routine, when the state counter shows 2, the 
termination of the timer T3 is checked (step #612). In the case where the 
timer T3 is not finished, the main routine is recovered. On the other 
hand, if the timer T3 is finished, the secondary transfer flag is reset to 
0 to end the secondary transfer (step #613). The copy flag is reset to 0 
thereby to finish copying (step #614). Then, the state counter is reset to 
the initial value 0 (step #615), thereby returning the flow to the main 
routine. 
A flow chart of FIG. 11 shows the content of the transporting process in 
the step #21. In the first place, the value of the state counter (initial 
value 0) is checked (step #701). Then, it is checked whether or not the 
primary transfer flag is 1 (step #702). When the primary transfer flag is 
1, it is detected whether the combining mode is selected (step #703). If 
the combining mode is selected, it is checked whether the area mode is B 
(step #704). When the area mode is B, the timer t6 is set to determine the 
starting timing of the transporting from the timing roller 46 (step #705), 
with the state counter being set to 1 (step #706) and the other 
transporting procedures being conducted (step #715) and the flow returned 
to the main routine. If the first transfer flag is not 1, or if the area 
mode is not B, the flow is moved directly to the main routine. Moreover, 
if the combining mode is not selected, general transporting is conducted 
(step #707) and the flow is brought back to the main routine. 
When the state counter is 1, at a next routine, the timer t6 is checked if 
it is finished (step #708). The flow is returned to the main routine if 
the timer t6 is not finished. On the other hand, the timing roller flag is 
set to 1 to start the transporting of paper P by turning the timing roller 
clutch 46a ON when the timer t6 is finished (step #709). In this case, the 
timer T3 is set to decide the timer of the transporting by the timing 
roller 46 (step #710) and the state counter is set to 2 (step #711). The 
flow advances to step #715, and the flow is once returned to the main 
routine. According to a next routine, when the state counter shows 2, the 
termination of the timer T3 is checked (step #712). In the case where the 
timer T3 is not finished, the main routine is recovered. On the other 
hand, if the timer T3 is finished, the timing roller flag is reset to 0 to 
end the transporting by the timing roller 46 by turning the timing roller 
clutch 46a OFF (step #713). The state counter is reset to the initial 
value 0 (step #714). The flow advances to step #715 and returns to the 
main routine. 
Now, how to control each element to achieve the combining copy mode which 
is the main concept of this invention will be depicted with reference to a 
flow chart of FIG. 12. 
When the first document is set and the print switch 200 is depressed in the 
combining copy mode set by the document selection button 232 and copy mode 
selection button 233, pre-scanning is carried out to detect the position 
of the simultaneous lever 102. Subsequently, the belt mark 11a on the 
transfer belt 11 is detected. A part of the photosensitive drum 3 
corresponding to the image section from the front end of the image to the 
position of the simultaneous lever 102 is charged for T1 seconds. The time 
T1 is calculated based on the position of the simultaneous lever 102 
(which is variable) detected at the pre-scanning time and the timer t2 
(which is fixed). Then, the exposure is started with a delay of time set 
by the timer t2 while the photosensitive drum 3 moves from the charging 
point to the exposing point and, the developing and first transfer are 
performed with delay of t3 seconds and t4 seconds, respectively. 
Accordingly, the image from the front end of the first document to the 
position of the simultaneous lever 102 is transferred (primary transfer) 
to the transfer belt 11. 
The document is exchanged with a second sheet. After the timer T1, in order 
to transfer an image from the position of the simultaneous lever 102 to 
the rear end of the image to the transfer belt 11, the part from the 
position of the simultaneous lever 102 to the rear end of the image is 
charged for T2 seconds, exposed with a delay of t2 seconds, developed with 
a delay of t3 seconds and transferred (primary transfer) with a delay of 
t4 seconds. In the above manner, the image from the position of the 
simultaneous lever 102 to the rear end of the second document is 
transferred (primary transfer) to the transfer belt 11. In other words, 
there are transferred (primary transfer) to the transfer belt 11 according 
to the above-described sequence of the procedures both the image in the 
section of the area mode A of the first document, i.e., from the front end 
to the simultaneous lever 102, and the image in the section of the area 
mode B of the second document, that is, from the simultaneous lever 102 to 
the rear end. 
If these images are transferred (secondary transfer) to a paper P at once, 
a copy of predetermined portions extracted from a plurality of documents 
can be obtained. 
In FIG. 13, a toner image on the transfer belt 11 and a copied output of in 
relation to the document and the position of the simultaneous lever 102 is 
illustrated. Referring to FIG. 13(a), a toner image of the section in the 
area mode A of the document set by the simultaneous lever 102 is held on 
the transfer belt 11. In FIG. 13(b), similarly, a toner image of the 
section in the area mode B of the document designated by the simultaneous 
lever 102 is held along with the toner image of FIG. 13(a) on the transfer 
belt 11. In FIG. 13(c), predetermined sections of a plurality of documents 
are outputted as one copy by transferring the toner images in the area 
modes A, B held on the transfer belt 11 to the paper at one time. 
According to the present embodiment, an intermediate transfer body, namely, 
transfer belt is used to obtain a clear image. Since the surface of the 
photosensitive body should be uniformly charged so as to obtain a clear 
image, it is necessary to completely remove the electric charges of the 
photosensitive body by the main eraser and to start charging earlier than 
the exposing point. If the image is held on the photosensitive body, 
however, since the toners statically adhered to the photosensitive body 
may be disadvantageously separated due to the removal of the electric 
charges or excessively charged, such a drawback is brought about that the 
image held on the photosensitive body be developed again. As such, it is 
considerably difficult to control charging, developing and erasing for 
every minute section when the photosensitive body is used. And, if the 
images are to be overlapped each other on the photosensitive body, the 
image section formed in the first process is undesirably charged, 
developed and erased in the next process, resulting in an unclear image at 
the boundary of the image sections. In contrast, if the images are to be 
overlapped each other on the transfer belt, since the image formation is 
carried out at the photosensitive body, the image is clear even at an end 
part thereof. Moreover, since the transfer is carried out at one time by 
the secondary transfer, an image clear even at the boundary is transferred 
to the paper. 
This invention is not limited to the aforementioned example, but is 
applicable to a general copying machine without using a transfer belt. In 
such case, a cleaning device should be arranged to be selectively in 
pressed contact with and detached from the photosensitive body. The 
cleaning device should be separated from the photosensitive drum after the 
document is developed so as to prevent the toners on the photosensitive 
body from being removed, and pressed against the photosensitive drum after 
the other document is developed and transferred. 
Furthermore, although the image section is divided into two by one 
simultaneous lever according to the above embodiment, it is needless to 
say that a plurality of simultaneous levers may possibly be provided to 
divide the image section into two or more thereby to obtain a combined 
copy. 
As this invention may be embodied in several forms without departing from 
the spirit of essential characteristics thereof, the present embodiment is 
therefore illustrative and not restrictive, since the scope of the 
invention is misdefined by the appended claims rather than by the 
description preceding them, and all changes that fall within the metes and 
bounds of the claims, or equivalence of such metes and bounds thereof are 
therefore intended to be embraced by the claims.