JPS60100157A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent electrification in the non-image region of a photosensitive drum and to prevent copying, etc. of the staining on an original cover by providing a destaticizing lamp array in the axial direction of the photosensitive drum and lighting selectively the lamps according to the information on the size of an original, the size of copying paper and magnification. CONSTITUTION:The light from a detecting lamp 6 provided to an original scanning carriage 10 is cast to the original on platen glass 1 and the position where the original blocks the lamp is detected by photodetectors 7a-7c provided to an original retaining plate 2, by which the size of the original is known. The microswitch group on the main unit side of the copying machine in a cassette insertion part is actuated by the projection array provided to a cassette, by which the size of copying paper is known. The region of the photosensitive drum to be projected with the original image is identified from such values and a copying magnification value. The electric charge in the regions except said region is erased by controlling the position and timing for lighting the destaticizing lamp array provided in the axial direction of the drum.

Description

[Detailed Description of the Invention] [Prior Art] In a normal copying machine, ? i-image-forming photoreceptor, 1
The entire surface of a photosensitive drum having a photosensitive layer on its surface is uniformly charged before being irradiated with a light image to form a latent image. However, since the width of the photosensitive drum is wider than the width of the maximum size copy paper that can be copied, copy paper of a size other than the maximum size may be set (not to mention that the largest size copy paper may be set). Even in cases where the latent image is developed, the main charge is applied to an area other than the area corresponding to the copy paper on the photosensitive drum.Conventionally, this charge is removed before the latent image is developed depending on the size of the copy paper. By preventing the image beating agent from adhering to that area, wasteful consumption of the developer and scattering within the apparatus are prevented.

However, for example, when copying a smaller A4-sized original in a device in which A3-sized photocopy paper is set, if the above-mentioned static elimination operation is performed according to the size of the copying paper, the above-mentioned Even if you can prevent wasted developer from disappearing or scattering, there may be dirt on the original cover for fixing the original or originals outside the A4 size original area of A3 size copy paper. If the belt used to convey the image to the exposure position is contaminated, the resulting image will be difficult to trample on.

〔the purpose〕

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make it possible to control both retention forming areas on a photoreceptor based on size information and copy magnification information of a document to be copied. Another object of the present invention is to provide an image forming apparatus that prevents wasted developer and scattering.

〔Example〕

Hereinafter, a detailed description will be given with reference to the drawings.

FIG. 1 shows a color copying apparatus as an example of an image forming apparatus to which the present invention can be applied continuously. In FIG. 1, the color copying apparatus is illustrated. After being sulfurized, the blue, edge and red filters 81 (a, b.

An electrostatic latent image of each color is formed by the image of the document incident through the image forming apparatus c and d). The double rotation σ drum 53 is developed in the developing device 200 with toner of a color corresponding to the tomoe of the filter 81, that is, yellow toner for the W filter, magenta toner for the green filter, and cyan toner for the red filter.
The latent image is then transferred to the transfer drum 53 using a filter of another color and a toner of another color corresponding to the latent image. 50.51 Selection means Document cover 2 and document exposure scanning table IQ [Provided document size detection means, indicated by Sasa No. 7o, both directions P Operation panel 1 is the user's input means
00, a microcomputer (not shown) as a control means, a rung string 19Q for static elimination, etc., and their configurations will be explained in sequence below.

Incidentally, here, cassettes 50 and 51 loaded on the copying machine are shown.
is A3. B4. It is assumed that it can accommodate transfer paper of A4 size.

The selection of which of the installed cassettes 50 and 51 feeds paper is made by selecting and operating one of the paper feed rollers 54 and 55. This selection is performed by a microcomputer, which will be described later.

The document size detection means is shown in FIG. 2 and is provided in the nine document exposure and scanning system. A platen glass 1 on which a document is placed, which is attached to an upper frame 5 of a document exposure scanning type copying device, and a document cover 2 which covers the placed document.
It consists of an original illumination lamp 4 for exposing an original and an original exposure scanning table having a reflective cover attached to the upper part thereof. The original exposure scanning table 10 is movably mounted on a rail 8 arranged substantially parallel to and facing the platen glass 1.
By being pulled by the stretched wire 9 and traveling in the direction A and in the direction B, the document placed thereon is exposed and scanned by the document illumination lamp.

The document size detection means is an IE placed inside the document cover 2.
The arrangement of the light receiving elements 7a, 7t) and 7Q, which are composed of I light receiving elements 7a, 7b, 7c and a detection lamp 6 mounted on the original exposure scanning table 10, is as shown in FIG. A is placed at the specified position on the Latin glass 1 at the position where the document cover comes into contact with it.
4. B4. Respective light receiving elements 7a, 7 are located at positions slightly in front of each end of each A5 size original and opposite to each other.
t), 7c are arranged. Furthermore, the light receiving element 7a,
7b and 7c are light receiving elements 7a, 7b, 7 arranged in a straight line so as to fill the travel path of the aforementioned detection lamp 6.
c receives the light from the above-mentioned detection lamp 6 traveling under it and outputs it, but if an original is interposed between the light receiving element and the detection lamp, the light from the detection lamp 6 is blocked by the original. The light receiving element does not output.

The light-receiving elements 7a, 7b, and 7c are connected to the positive input terminal of the comparator of the light-receiving section detection circuit shown in FIG. etc., to the document size detection signals shown in the fifth IQI (a) to (d). Note that 22 is an input bus to be described later.

FIGS. 5A to 5A each show the timing of the output signal of the light receiving section detection circuit according to the size of the f5 original document. Details of each waveform chart The upper row shows the advance signal of the scanning table 10 of the microcomputer, which will be described later. That is, it shows the timing of the output signal of the light-receiving section detection circuit when the detection lamp 6 on the scanning table 10 travels the entire scanning width once. FIG. 5(a) shows the case where the original placed on e is lit by candlelight, and since there is nothing to fuse the light from the detection lamp O, all the light receiving elements 7a and 7b are used.

7C is output, and three /.Irepel signals are output from the light receiving section detection circuit. In Figure 5 (1)), the loaded original is A4
In this case, the light receiving element 7a does not output light because it is blocked by the original, and the light receiving element 7b and 70 do not receive mt4fT, so they are outputted, and a high-level signal No. 41 of 2 is output from the circuit. , Fig. 5(C) shows a station where the original placed is B size, and the light receiving elements 7a and 7b completely block the light and do not output, and only 7C receives the light and outputs 1. A 7-level signal is output from the circuit. FIG. 5(d) shows a case where the original is A5 size, and the light receiving elements 7a, 7b,
All of 7C is blocked from light and there is no output, and there is no output signal from the circuit.The output terminal of this light receiving section detection circuit, that is, the collector terminal of the transistor, is connected to the input/output board of the microcomputer, which will be described later. The output signal of the light receiving part detection circuit is input to the microcomputer and decoded, and #Y IF
f The size of the reward is detected.

Next, the means for detecting the size of the cassette installed in the copying machine will be explained with reference to FIG. 6 and MT17.

As shown in FIG. 6, four parts 56, 57, and 58 are formed at the innermost part of the cassette loading platform of the copying machine, and microswitches MS1, 57, and 58 are formed in each part. Me2°MB5 is placed. Micro switch MS1゜MB2. MB3 outputs a signal depending on whether it is ON or OFF. It is connected to the interface circuit 62. Note that 22 is an input bus to be described later.

On the other hand, the front side of the cassette is formed with protrusions that fit into the recesses 56, 57, and 58 when the cassette is installed. For example, the A4 cassette 50 in the figure has a protrusion 15.
9.60 is formed, and when installed, the four parts are 56.58
The microswitches MSI and M85 are energized and turned ON.

On the other hand, the A3 cassette has a micro switch ME11゜MF.
37. Three protrusions are formed so that all of MB5 is energized and turned ON, and one protrusion is formed on the 84 cassette so that only microswitch ME+5 is energized and turned ON. has been done.

Microswitched As when adhering cassettes of various sizes
1, MB2,) The relationship between ON and OFF of JS5 is shown in the table of FIG. The interface circuit outputs a signal depending on the ON/OFF 1fA, but this interface circuit outputs a signal via the input bus 22.
'T is connected to a microcomputer, and the signal is sent to the microcomputer and decoded to detect the loaded cassette size.

Next, the variable magnification mechanism will be explained according to FIG.

A lens 70, which imitates the image of the original on the photosensitive drum 52, is fixed on a support 71 that meshes with a drive gear 72, which is driven by an indeterminate drive motor.

By driving the drive gear 72, it can move in the same directions as arrows a and D, and by changing the position of the lens 70, the same magnification and variable magnification of the image to be copied are performed.

3, which is output along the transfer path of the support 71 when the light is blocked.
While photo interrupters Q, , '4, q, 3 are arranged, one of the shift interrupters Q, , Q, , Q, 1 is placed on the support 71 due to its movement.
A detection plate 79 that blocks light is attached to the lens 7D, and the position of the lens 7D is detected through both of them.

On the other hand, the drive gear 72 has three notches 75 on the outer periphery.
, 76, 77 are meshed with gears fixed to the disk 73 in the same manner. A lock rod 78 is arranged on the circumference of the diagonal disk 73, and a spring 79 and a solenoid 74
It fits into and disengages from the cutout portions 75, 76, and 77 through the slits 75, 76, and 77, thereby locking and releasing the rotating position gt of the disk. As a result, the position of the lens 70 is locked to and released from the predetermined constant magnification mode position.

The stop position a of the disk 73 due to the engagement of the lock rod 78 with the grooves of the notches 75, 76, 77, that is, the lens 7
The lock position 0 corresponds to the position at which the detection plate 79 detects the photointerrupters Q, , Q, , Q, respectively.

At the position where photo interrupter Q1 is detected, the mode of the variable magnification mechanism becomes equal magnification mode, and photo interrupter Q1 is detected.
, (★In knowledge 1tt, py, q diagram has the symbol M2
, the position of the reduction 1 mode indicated by the A5 arrow, that is, the magnification mode from A5 size original to B4 size transfer paper, or from B4 size original to A4 size transfer paper as shown in FIG. Become. ), odd interrupter Q
The detection position of s is the position of the reduction 2 mode shown by the arrow M1 in FIG. 9, that is, the magnification change mode from A5 size original to 84 size transfer paper shown in FIG. 810.

In addition, in the case of Honwara fields, A4→ marked with an X in Figure 10
A3, A4→B4. It is assumed that scaling from B4 to A3 is not performed.

The photointerrupters 4, Qs, and the solenoid 74 are connected to a microcomputer via a load drive circuit, and the microcomputer activates the solenoid 74 in response to detection signals from the photointerrupters Q+, Qt, and Qm. In addition, in this embodiment, in order to make the explanation fli'IM, enlargement and scaling of A4-dA!, A4→84, and B4→A3, which are marked with in FIG. 10, is not performed. Note that the variable magnification mechanism is not limited to this, and may be of a zoom type.

Next, the configuration of the microcomputer that controls the entire copying apparatus will be explained according to Figure @11.

The microcomputer is a central processing MR, which controls the entire system by processing various signals. PU 12, data bus 15. Through M.
The i(OM 19) is a read-only memory in which the entire control program is stored.

It is configured by connecting an ltAM 20, which is a random access memory, and an input/output board 11.

The overall load of the copying apparatus, such as the W of the original exposure scanning system mentioned above, the Japanese illumination rung 4, the detection lamp 6, the lamp embedded in the operation key on the operation panel described later, and the lamp row for one extra width in the width direction is, for example, It is connected to the input/output boat 11 via a load control circuit as shown in FIG.

The load control circuit shown in FIG. 12 is a load control circuit for the original illumination lamp 4 and the detection lamp 6 described above, and is an amplification transistor whose base terminal is connected to the input/output port 11 of the microcomputer via the output bus 21. and a switching transistor whose pace terminal is connected to the collector terminal of the amplification transistor.
The lamp 14 is connected to the output terminals 40, 411ifi of the load control circuit via a document illumination lighting circuit (not shown), and the document detection lamp 6 is connected to the output terminals 42, 451 and the throat resistor 44. connected to. The resistor 44 may not be inserted depending on the load.

The load control of the original illumination lamp 4 and the original detection lamp 6 is as follows.
According to the program stored in the CPU 12 and the ROM 19, signals are output to the data node 13 in synchronization with the timing signals of the control signals 15 to 18, and the input/output port 11
(output via t'') (controlled by a signal output from step 21 to the load control circuit).

The load control such as the embedded lamp of the operation key is also performed by the microcomputer via a similar load control circuit.

On the other hand, the K1β size detection signal of the above-mentioned light receiving section detection circuit, the detection signal of the installed cassette size of the interface circuit 62, and the photointerrupter Q, , Q of the variable magnification mechanism.
! , Qs detection No. 18 and other sensors are input to the input/output boat 11 via the input box 22, and are outputted OP[ in synchronization with the control 11 timing signals 15 to 18.
The CPυ121C rainbow cutting is performed according to the program inputted to the r 12 and stored in the ROIJ 119, and is reflected in the control of the entire device by the OPU 12.

Next, the operation shown in Fig. 13) Kune A/I DOt A
give up. The operation spring /I/loo has various displays and each operation key i! which is the operator's input means. +≦is arranged.

JIj 4 production keys are copy start key 72, upper cassette) selection key 64, lower cassette R selection key 65° ten key group 6
7. Various mode selection keys W-69 and shade designation keys 71 are arranged.

The copy start key 72 is an input key for starting the copying operation, and the upper cassette selection key 64 and the lower cassette selection key 65 select the upper or lower cassette from among the installed cassettes. The scaling selection keys 701, 702, and 703 are keys for specifying the scaling ratio, for example, from A3 to A4.
．． Supports variable magnification modes from A5 to B4 and B4 to A4.

A group of ten keys 67 are operation keys for entering the number of copies by +ltl.

All of the operation keys are arranged on a matrix circuit consisting of a large number of contacts indicated by numerals 2'5 to 58 shown in B141M, and when each is energized by the operator, its input signal is sent to the input/output board 11. The data is input to the CPU 12 via the CPU 12 and read M times.

For example, to start copying, the operator presses the copy start key ([13
When you press 72) in the figure, 1 contact 23 of the matrix circuit (23 is the contact of the copy start key) is selected.
Signals outputted from pυ12 to the matrix circuit scan lines S1 to F34 via the input/output port 11 and the output path 21 are received by the return lines R1 to R4, and are sent to the input/output port 11 via the input bus 22 again. The key is input to the OF'U 12 via the CPU 12, and is decoded as a copy start key by the cPU 12 to start the copy operation.

In addition, all the operation keys except the numeric key group 67 and the #dark designation key 71 are self-illuminated and have small lamps embedded inside.
Each voltage lamp is controlled by the CPU 12KM via a load control circuit as shown in FIG. 12 described above. That is, when a certain operation key is activated by the operator,
The small lamp of that operation key is lit, and the other operation key clamps are turned off.

On the other hand, on the operating spring 11/100, there is a 7-segment Ll display section for displaying the number of sheets. ;D 66, various display group 6
8. Variable magnification mode display section 700, cassette size display section 7
5 is placed.

The various displays #68 include a cassette-free display 75, and the cassette-free display 73 is shown when the mounting cassette is selected according to the original size, and when there is no mounting cassette.

The cassette size display section 75 is the upper cassette selection key 64
Alternatively, the size of the installed cassette selected by pressing the lower cassette selection key 65 is displayed.

FIG. 15 shows the position n relationship of one row of static elimination runs 190 with respect to the photosensitive drum 52. As shown in the figure, the static elimination lamp array 190 has eight
The lamps 191 to 198 are arranged in a line in the "1" direction of the photosensitive drum 52, and each lamp 191 to 198 is individually lit at the same time.When all the rungs 191 to 198 are lit, , the electric charge on the photosensitive drum 52 is removed uniformly across the width direction without interruption.
The point f4 written in 2 indicates the image area corresponding to the document size, S indicates the width of A4 size, M x B4 size, and L indicates the width of A3 size. When only the lamps 191 and 198 are turned on, charges in an area larger than the width of the A'5 size image in the transverse direction are removed. When the lamps 191, 197, and 198 are turned on, charges in an area larger than the middle of the B4 size image in the short direction are removed. Sunta, 191,1
When 96, 197.19f+ is turned on, the charge in the area of ``l'' or more of both images in the width direction of an A4 size sheet is removed.

In FIG. 16, the drive circuit 1 for one row of static elimination runs 190 is indicated by 11, and the reference numeral 199 is a driver for individually driving the lamps 191 to 198. The driver 199 includes I1, which will be described later.
A lighting control signal T, ~, is input from the 0 boat, and lamps 191 to 198 are selectively turned on by this signal. That is, when the lighting control signal I is "0", the lamp corresponding to that signal is lit, and when it is "1", the lamp is turned off. Therefore, the eight lamps 191 to 198 can be selectively turned on by the 8-bit parallel inputs T1 to T1. For example, when the signals I, ~I, are set to "00001111 J," the lamps 191 to 194 are turned on and the lamps 195 to 198 are turned off.The present invention also applies if the charger 80 and developer n 200 are controlled to be driven separately. The gist of this remains the same.

Return to Figure 15. A magnet 146 is attached to one end of the photosensitive drum 52.
is provided, and the position of the photosensitive drum 52 is detected by the magnet 146 and the movement hole TO 147. Note that the state in which the hole 10147 is operated by the magnet 146 is called the home position of the photosensitive drum 52. In addition, there is a pulse generation plate 176 provided on the same IFIII as the photosensitive drum 52, and a photosensor 177 that detects a groove provided on the pulse generation plate. Pulse C
P is output. This clock pulse CP is input to the aforementioned microcomputer and counted. Further, the home position signal HP mentioned above is also input to the microcomputer and is used to reset the count lσ to "0".

Next, the operation of the embodiment of the present invention having the above configuration will be explained with reference to the flowcharts of FIGS. 17, 18, and 19, and FIGS. 20 and 21.

In the flowchart of FIG. 20, in step S1, it is determined whether the copy start key is turned on.

In other words, in the case of a YKe with the copy start key turned on, the CPU
12 proceeds to the next step 82 to S5.

In steps 82 to S5, it is determined whether the selected magnification mode (in this embodiment, only the reduction mode is shown, but the same applies to enlargement) or the same magnification mode. Next steps A, B, O for each mode determined here.

In step D, move and center the variable magnification optical system. Each operation A, B, O, and D is in each mode and is controlled by the same aircraft, so redundant explanations will be avoided. To explain only A, in steps 6 to 11, the variable magnification lock is released and the variable magnification motor is turned on;

(Optical system type #) is detected, the variable power motor is turned off and the variable power is locked. After the lens position 1# of the variable magnification optical system is determined, the size of the document is detected (s12) in the sequence described above and the process proceeds to LE.

That is, the CPU 12 turns on the detection lamp 0N-j, and then moves the original exposure scanning table 10 forward over the entire scanning width.

The source of the detection lamp, which travels as the scanning table 10 moves, passes through the document placed on the platen glass 1 to the third
By receiving or fusing the light into each of the light receiving elements 7a, 7b, and 7a shown in the figure, a detection signal pattern as shown in FIG.
The document is read into the PU 12, and the document size is decoded from the signal.

Before starting the copy sequence, the detected document size and the selected reduction mode (A3→B4,
B4→A4, A5→A4), forward, etc., depending on the 1% mode, ;fr, As shown in FIG. 1B, an image is formed on the photosensitive drum in the document feeding direction. That is, for example, when the document size is A5 and the reduction mode from A3 to B4 is selected, the document image is formed between the @ in Figure 17 and the point 0 in Figure 18. It can be seen that this is the same area as 84 equal magnification +4. For example, if the original size is B
If the reduction mode of A3-+A4 is selected in step 4, the original image is formed in the position of ■, therefore, in the area at 0 dimensions from Oa in FIG.

FIG. 19 shows a control time chart for one rotation of the photosensitive drum.

In FIG. 19, provided on a part of the photosensitive drum,
When the home position is detected by a sensor (not shown) and a home position signal serving as the starting point for single-plane image formation is output, the microcomputer 12 starts counting clock pulses CP from this point on. When the microcomputer 12 counts the CP count by ONT 1, it transfers 191 to 198 of the rung row 190 to a cassette as shown in FIG. Lighting starts selectively depending on the size of the paper stored. That is, if the paper in the cassette is A4 size, the lamp 196,
197, 198, if it is B4 size, i97
, 198 are turned on, and the others are turned off. On the other hand, in accordance with the feeding direction (and each document size shown in FIG. From 0NTi of the clock pass/I/splash CP in the figure, ONT 2 to 0
The lamp array 190 is selectively turned on during 1 hour at the NT10 dimension.

For example, when the original size is detected as A4, A3 → A4 (Dm
/J) mode is selected, the lamp array 190 in CNT 1 is selectively lit, and the rung array 190 in ONT 4 is fully lit. As a result, static electricity is removed only from unnecessary areas except for the original image.

The above situation will be explained using the flowchart shown in FIG. In steps 22 to 24, as described above, the selected magnification mode or the same magnification mode and the detected raw material size are determined, and a predetermined count value is set. For example, if YFiS is selected in step 56, this indicates that the document size is A3 and the magnification ratio is (B4→A4). In other words, in Figure 17 it is ``■'', and in Figure 18 it is 1iIjI'! ! The head area is between 0 and ■ position. Then, in step 37, the counter ONTl/(predetermined value ONT7 is decremented by 7') as shown in FIG. If so, step 4
7. At step 48, the counter is set, and at step 49,
roJ is output to nine lighting control signals 1 to Ts shown in FIG. 16, and all rungs corresponding to the signals are lit.

Next, in step 50, the counter ONT is set to clock hull x
After counting (CP) by 0NTI,
In steps 51 and 53, the cassette size is detected. In step 55, the cassette size is determined to be A4. Assuming that the cassette is A5, the Stella 152 outputs ``5Kr0111111DJ'' in order to neutralize the unnecessary image part in the middle direction on the photosensitive drum.Next, when ONT 8 is counted in step 56, the direction of document feeding is Step 5 to remove static electricity from unnecessary image parts
At step 7, output ``0OOOOOOOOJ'' to 11~''S and turn on all the lamps.If the copy is completed, turn off the lamps and strag (step 58).

In addition to controlling the static elimination run described above, the image forming area may be controlled by separately driving the developing device and the charging device. Further, by arranging a large number of document size detection means at a predetermined position, the image forming area can be controlled in the same way as in the present embodiment even for documents of α size such as postcard size.

Father, in addition to standard variable magnification, the same applies to stepless variable magnification such as zoom.

Next, the control of the +lJ rotational image forming area of the drum will be explained in more detail. FIG. 22-A is an explanatory diagram of a method of controlling the image forming area by driving the anti-vibration ramp ft in divisions as described above. FIG. 22-B is a diagram showing the position f of the drum 52% neutralization rung 190 in the front and metering manner. It should be noted that there are 1,190 LED arrays with one extra run, J, and 191 to 198 are LHiD blocks.

:A22-B shows the LIIiD'γ ray lighting circuit. Each data line is connected to the DATA Gronk select signal s.
When un is set to '1'0' and the DATA pinto JnmQ in the Glock is set to 'Q', the LED of the corresponding bit lights up, and when it is set to '1', the LED goes out. A dynamic lighting timing chart is shown in FIG. 22-0.

Output 8 bits of data to be lit to block n during period Tn.

The above control is shown in FIG. Figure 23 shows the image form FIt
3 is a flowchart for controlling the static elimination run 1 in the width direction of the drum and in the feeding direction of the document according to the fR region. STETSU 12
2 to 45 are the same as in FIG. 21. Steps 60-71
Then, as in I'lAT MF steps 25 to 45, the copy size is detected from the original size and magnification, and predetermined data indicating which IJD should be lit is set in the DATA bit. Each data is 8 bytes and the LED array is also 6
Consists of four IJDs. In the next step 72, if the scanner is in the home position, step 775
, 74 to reset the counter, and step 75 to IJD.
Set all drive data bits to 0" and turn on all lights. At step 76, set the counter to 0NT1 (FIG. 19). At steps 77 and 78, data is output, and the data bits are set to 0". In order to eliminate static electricity outside, LFi
Controllably lights up D.

Next, the rear end in the feeding direction (ONT=n) is the stethoscope 79, and when it counts up, all the LFiD arrays are turned on (D
ATA=a//”o”) and perform blank exposure (
Step 80). Then, in step 81, when the copying is completed, DATA=a l l "1" is set to L.
Turn off the publication.

For image forming apparatuses that only have a same-magnification mechanism, M2
The control flow chart in FIG. 25 will be described with reference to the time charts in FIG. S and FIG. 24. In step 205, the HP multiplication signal is turned ON L, and the stethoscope 20
6 resets the counter.

When the IP multiplication signal is turned OFF (in step 207), all static elimination lamps 190 are turned off in step 208. Then check the manuscript size on Sudetsu 7210, 21+, press 1, and set]
For example, if it is A3, 0111 with Stesoge 211
Output 11jO, width direction! Do the whole army.

Then, in step 212, the counter = ONT 1 is detected, and if it is Y, all the lamps are turned on to eliminate static electricity in the feeding direction of the rear edge of the document.In step 219, if the copy is finished, all the lamps are turned on. Off and strug. Note that steps 212, 216 and 218 are the clock numbers 0NT5 and 0NT2, which indicate the length of the original, as shown in FIG.
, indicates the count value of O+JT1.

In addition, in Figs. 2 and 3, reflex pharynx photo sensors are used at 7a and 7b in Fig. 3 to detect the size of the document in the middle direction.
, 7bT instead of 7c, as shown by the dotted line in the figure.
, 7 cl may be provided at the position shown in the figure.

The small size sensor 7a may also be used to detect the size in the length direction. The size in the length direction is obtained by comparing the sensor time by the sensor and the timer time 1. As described above, automatic scaling is also possible based on the detected document size and information from the cassette size detection means shown in FIG. A reflective or transmissive sensor may be provided close to the document feeding mechanism to detect the size of the document while it is being fed.

〔effect〕

As described in detail above, since the image is formed in areas other than the desired image forming area, an easy-to-see image is obtained, and there is no waste of developer, etc. We were able to provide an i+fii image forming device that would save M costs.

[Brief explanation of the drawing]

No. 11'N is a structural diagram of a color copying apparatus. FIG. 2 is a diagram showing the document size detection means. FIG. 5 is a diagram showing power distribution of the light receiving element. @41:Xl is a diagram showing a light receiving section detection circuit. FIGS. 5(a) to 5(d) are diagrams showing document size detection signals. FIG. 6 is a diagram showing a means for detecting the size of a cassette. FIG. 7 is a diagram showing the relationship between cassette size and microswitch. Drawing 8 is a diagram showing the variable magnification mechanism. Figure r49 is a diagram showing how magnification changes on the grating. FIG. 10 is a diagram showing the relationship between document size, cassette size, and mode. FIG. 11 is a diagram showing the configuration of the microcomputer. FIG. 12 is a diagram showing the load flrl+ control circuit. FIG. 13 is a diagram showing the operation panel. FIG. 14 is a diagram showing a matrix circuit. FIG. 15 is a diagram showing the positional relationship between the static elimination lamp array and the drum. FIG. 16 is a diagram showing a drive-'TjI circuit for a static elimination rung string. 17 and M1S are diagrams showing image forming positions in each mode, and FIG. 19 is a control time chart regarding one rotation of the photosensitive drum. FIGS. 20, 21, 25, and 25 are flowcharts for unloading the image forming area. FIG. 22-A is an explanatory diagram of divisional driving of the static elimination rung. @22-B is a diagram showing the LED array lighting circuit. FIG. 22-0 is a diagram showing a dynamic lighting timing chart. FIG. 24 is a control time chart. 52 Photosensitive drums 7a, 7b, 7c Original size detection means 12 P1λ 1901 Rinse rung 191-198 LED block 3rd town 4th w φ Sth second -1-+→1000-- Fig. 75 Fig. 76

Claims (1)

[Claims] a size output means for outputting document size information; a variable magnification output means for outputting variable magnification information; and an area determination child actor for determining both desired image forming areas based on information from the size output means and the variable magnification output means. An image forming apparatus comprising: an area control means for controlling the feeding direction of the original and the width direction of the original in the area based on information from the determination means.