JPS6273282A - Image forming device - Google Patents

Abstract

PURPOSE:To detect whether an original is set at a correct position or not by moving a photodetection part to one specific fixed scale side firstly and then moving a detecting means for a specific time along the 2nd original set reference when an erasure range is specified. CONSTITUTION:An original platen 2 is provided with an excessive part ya so as to obtain the size slightly larger than the maximum original size and when one of operation keys 30a-30d is operated during the specification of the erasure range, the setting position of the original is detected by moving a spot light source 131 and the photodetection part 132 to the excessive part ya or moving the spot light source 131 and photodetection part 132 at the excessive part ya in an (x) direction. Consequently, the erasure range is prevented from being specified while the original is set at a wrong position and the misspecification of the erasure range and the miscopying of the original are eliminated. Further, the setting position of the original is detected automatically by operating one of the operation keys 30a-30d, so the operativity is excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus applied to, for example, an electronic copying machine.

(Technical Background of the Invention and Problems thereof) Generally, electronic copying machines have the function of copying an original image onto paper as is, or enlarging or reducing the original image and making a copy.

Incidentally, recently, copying machines have been developed that are capable of specifying a desired portion of a document image and erasing the image of the specified portion before making a copy. In this type of copying machine, if it is possible to detect whether or not the document for which the erasing range is to be specified is correctly set on the document table, copying errors can be prevented, which is convenient in practice.

[Object of the invention] This invention was made based on the above circumstances,
The purpose is to provide an image forming apparatus that can detect whether or not a document is correctly set on a document table.

(Summary of the Invention) This invention, for example, irradiates a spot light onto an original image, moves this spora l light to designate an erasing range, and emits light onto a photoreceptor drum corresponding to the designated erasing range. An image is formed by irradiating an electrostatic latent image or charging to erase an electrostatic latent image or charge. When specifying the erasing range, first, the light receiving section is moved to a predetermined one of the fixed scales, and then the detecting means is moved for a predetermined period of time in accordance with the second original setting standard. , it is designed to detect whether or not the original is set in the correct position.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 3 and 4 schematically show an image forming apparatus of the present invention, such as a copying machine. A document table (transparent glass) 2 for supporting a document is fixed to the upper surface of the copying machine main body 1. At both ends of this @ stacking table 2 are fixed scales 2 that serve as a reference for setting originals! , 22 are provided, and furthermore, a document cover 11 and a work table 12, which can be opened and closed, are provided near the document table 2. And the above manuscript fg
Q: The placed original is exposed to the exposure lamp 4 and the mirror 55.
．． An optical system consisting of 6.7 and 6.7 is reciprocated along the lower surface of the document table 2 in the direction of arrow Ela, thereby performing exposure scanning. In this case, mirror 6.7 is moved at a speed of -5 1/'2 to maintain the light exposure length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4, is reflected by the mirror 5, 6, 7, passes through the variable magnification lens block 8, and is further reflected by the mirror. 9 and guided to the photoreceptor drum 10.
J, which is imaged on the 00 surface, is shaped like a sea urchin.

The photosensitive drum 1110 is rotated in the direction of arrow C in the figure,
First, the surface is charged by the charger 11 for charging. Thereafter, the image is exposed to slit light to form an electrostatic latent image on the surface. This electrostatic latent image is made visible by applying toner by the developing device 12.

On the other hand, the paper (transferring material) P is taken out one by one from the selected upper paper feed force hitter 13 or lower paper feed force cellar 1 to 1°1 by the delivery roller 15 or 16, and the taken out paper is guided through a paper guide path 17 or 18 to a pair of registration rollers 19, and guided to a transfer section by this pair of registration rollers 19. Here, the paper feed force cellars 1 to 13.14 are the main body 1.
It is removably provided at the lower right end of the screen, and either one can be selected on the operation panel described later. The cassette size of each paper feed force set 13, 14 is detected by a cassette size detection switch 601, 602.The cassette size detection switch 601, 602 detects the insertion of cassettes of different sizes. It is made up of multiple microswitches that are turned on and off depending on the situation.

The paper P sent to the transfer section is brought to the surface of the photoreceptor drum 10 by the transfer charger 200, and the toner image on the photoreceptor drum 10 is transferred by the action of the charger 20. The transferred MP for I,: is electrostatically peeled off from the photoreceptor drum 10 by the action of the peeling charger 210,
The image is sent by the conveyor belt 22 to a fixing roller 23 as a fixing device provided at the end thereof. The transferred image is fixed by passing through this, and the paper P after fixation is discharged to a tray 25 outside the main body 1 by a pair of paper discharge rollers 24 . After the photosensitive drum 10 has been transferred, the charge is removed by the snow removal charger 26, residual toner on the surface is removed by the cleaner 27, and the residual image is erased by the charge removal lamp 28, so that the initial state is maintained. It is expected that it will be reinstated. Incidentally, 29 is a cooling fan for preventing a temperature rise inside the main body 1.

FIG. 5 shows an operation panel 30 provided on the main body 1. 30+ is a copy 47-130 that commands the start of copying.
2 is a numeric keypad for setting the number of copies, etc.; 303 is a display unit for displaying the operating status of each part and paper jams; and 304
305 is a cassette display section that displays the selected cassette; 306 is a magnification setting that sets the copy enlargement and reduction magnification in a predetermined relationship; key, 307 is a zoom key for steplessly setting the enlargement/reduction magnification, 308 is a display section for displaying the set magnification, 30s is a density setting section for setting the copy degree, 30a, 30b, 30c, 3(') d is an operation key for moving the spot light source without indicating the erasing position of the original, which will be described later; 30e is a position designation key for inputting the coordinate position indicated by the spot light source; This is the erase range specification key.

FIG. 6 shows an example of the drive source configuration of each drive section of the copying machine configured as described above, and is configured with the following motors. That is, 31 is a lens motor, which changes the magnification by 1! This is a motor for moving the position of the lens block 8. Reference numeral 32 denotes a mirror motor, which connects the mirror 5 and mirrors 6 and 7 for variable magnification.
This is a motor for changing the distance (optical path length) between the

A scanning motor 33 is a motor for moving the nyt, the lamp 4, the mirror 5, and the mirror 6.7 for scanning the original. Reference numeral 34 denotes a shutter motor, which is a seventh motor for moving a shutter (not shown) for adjusting the width of the WI voltage applied to the photosensitive drum 10 by the charger 11 during zooming. A developing motor 35 is a motor for driving the developing roller of the developing device 12 and the like. 36 is a drum motor, which is a motor for driving the photosensitive drum 10. 371 is a fixing motor, which is a motor for driving the paper conveyance path 22, the pair of fixing rollers 23, and the pair of paper discharge rollers 24. 38 is a paper feed motor, and the feed roller 1
This is a motor for driving 5 and 16. A paper feeding motor 39 is a motor for driving the registration roller pair 19. 40 is a fan motor, which is a motor for driving the front cooling group fan 29.

FIG. 7 shows a drive mechanism for reciprocating the optical system. That is, the mirror 5 and the exposure lamp 4 are supported by a first carriage 411, and the mirror 6.7 is supported by a second carriage 422, and these carriages 411 and 412 are guided by guide rails 421 and 422 in the direction of arrow a. It is said to be able to move in parallel. Further, the four-phase pulse 33 drives the pulley 43. An endless belt 45 is stretched between the pulley 43 and the idle pulley 44, and one end of a first carriage 411 that supports the mirror 5 is fixed to a midway portion of the belt 45. On the other hand, the second mirror supporting mirror 6.7
Two pulleys 47.47 are rotatably provided on the guide portion 46 of the carriage 422, spaced apart in the axial direction of the rail 422.
4B is hung. One end of this wire 11B is connected to the fixed part 49, and the other end is connected to the coil spring 50.
They are fixed to the fixing portions 49, respectively. Further, one end of a first key 17 ridge 411 is fixed to the middle part of the wire 48. Therefore, by rotating the pulse motor 33, the belt 45 rotates and the first carriage 411 is moved, and accordingly, the second carriage 42 is moved.
2 is also moved.

At this time, since the pulleys 47 and 47 serve as movable pulleys, the second carriage 422
are moved in the same direction at 1/2 the speed. In addition, first,
The direction of movement of the second carriages 411 and 412 is controlled by changing the direction of rotation of the pulse motor 33.

Further, on the document table 2, a copyable range corresponding to the specified paper is displayed. That is, the cassette selection key 30.
Let the paper size specified by (Px, Py) be,
If the copy magnification specified by the magnification setting keys 306 and 307 is K, the copyable range (X, V) is [x=P
x/KJ.

ry=Py/Kl. This copyable range〈X, y)
In the X direction, a pointer 51 provided on the back side of the document table 2
．． 52, and the y direction is indicated by a scale 53 provided on the upper surface of the first carriage 411.
and the distance between the fixed scales 2I.

, the finger sets 51 and 52 are connected to the pulley 54 as shown in FIG.
．． 55 via a spring 56. The pulley 55 is a motor 58
This motor 58
The distance between the fingers 51 and 52 can be changed by being driven according to the submerged copyable range in the X direction.

Further, the first carriage 411 is moved to a predetermined position M by driving the motor 33 according to the paper size and magnification.
(home position according to the magnification). When the copy key 301 is pressed, the first carriage 411 is first moved toward the second carriage 412, and then the lamp 4 is turned on and moved away from the second carriage 412. When scanning of the original is completed, the lamp 4 is turned off and the first carriage 41
1 is returned to the home position 15I.

FIG. 9 shows the overall control circuit.

The main processor group 71 detects inputs from input devices 75 such as the operation panel 30 and various switches and sensors, such as the force cell 1 helirise detection switches 60s and 602, and drives the various chargers. The high-voltage transformer 76, the static elimination lamp 28, the plate electrode 27a of the cleaner 27, the heater 23a of the fixing roller pair 23, the exposure lamp 4, and each of the motors 31
~40.58 etc. to perform the above-mentioned copying operation, as well as spot light 8!13i, light receiving section 132,
Pulse motor 135, memory 1401 erase array 150
, a buzzer 170 as a notification means for the array drive unit 1601
etc., to detect the position where the original is set,
It performs the operation of erasing unnecessary parts of the original.

Note that the spot light source 131, light receiving section 132, pulse motor 135, erasing array 150, array driving section 160, buzzer 170, and memory 140 will be described later.

Among motors 31 to 40.58, motor 35.37
．． A toner motor 77 that supplies toner to the developing unit 40 and the developing device 12 is controlled by the main processor group 71 via a motor driver 78.
are controlled by the first sub-processor group 72 via a pulse motor driver 79, and the motors 36, 39, 38, 58
is filled by the second sub-processor group 73 via the pulse motor driver 80. Further, the exposure lamp 4 is connected to the main processor group 7 via a lamp regulator 81.
1, and the heater 23a is controlled by the main processor group 71 via the heater control section 82. Then, from the main processor group 71 to the first and second sub-processor groups 7
Drive and stop commands for each motor are sent to 2.73, and
．． A status signal indicating the drive/stop state of each motor is sent from the 211th processor group 72, 73 to the main processor 71. Further, the first sensor group 72 receives position information from a position sensor 83 that detects the initial position of each of the motors 31 to 34.

FIG. 10 shows an example of the configuration of the main processor group 71. One-chip microcomputer 91 (hereinafter referred to as
The microcomputer (hereinafter simply referred to as a microcomputer) detects human power on keys on an operation panel (not shown) and performs various display controls via an input/output board 92.

Furthermore, the microcomputer 91 is expanded by input/output ports 93-96. A high voltage transformer 76, a motor driver 78, a lamp regulator 81, and other outputs are connected to the input/output port 93, and a size switch for detecting paper size and other human power are connected to the input/output boat 94. A copying condition setting switch and its oil input are connected to the output boat 95. Note that the input/output port 96 is an option.

FIG. 11 shows an example of the configuration of the first sub-processor group 72. The microcomputer 101 is the main processor group 7
1 is connected. Programmable interval
The timer 102 controls the phase switching interval time of the pulse motor, and when a setting value is set from the microcomputer 101, counting of reference clock pulses is started based on it, and when the clock runs out from 1 to 1, the end pulse is sent to the microcomputer. The signal is output to the interrupt line 101. Furthermore, the microcomputer 101 receives position information from the position sensor 83 and is connected to input/output boats 103 and 104. The input/output boat 104 is connected to the motors 31 to 34.135 via the pulse motor driver 79. The input/output board 103 is used, for example, to output status signals of each pulse motor to the main processor group 71.

FIG. 12 shows the configuration of the second sub-processor 11 group 73. The microcomputer 111 is connected to the main processor group 7.
1 is connected. Programmable interval
The timer 112 controls the phase switching interval time of the pulse motor, and when a set value is set from the microcomputer 111, it starts counting the reference daily pulses based on it, and outputs the end pulse when the count is out. It has become. This end pulse is applied to the latch circuit 113.
The output is supplied to the interrupt line and input/output board input line of the microcomputer 111. In addition, an input/output boat 114 is connected to the microcomputer 111.
Motors 36, 38, 39, and 58 are connected to this input/output boat 114 via the pulse motor driver 80.

Figure 13 shows the control circuit of the pulse motor.
The input/output boat 121 (corresponding to the input/output boats 104 and 114 in Figs. 11 and 12) has a pulse motor driver 1.
22 (corresponding to the pulse motor drivers 79 and 80 in FIG.
．． 38.39.58.135) windings A, B,
A and B are connected.

FIG. 14 shows a method for controlling the speed of a pulse motor. FIG. 3(a) shows the speed curve of the pulse motor, and FIG. 1(b) shows the phase switching interval.

As is clear from this figure, the phase switching interval is good at first;
They gradually shorten, then become evenly spaced, then gradually lengthen again, and then stop. In other words, this indicates the through-up and through-down of the pulse motor, starting from the self-starting region, being used in the high-speed region, and finally falling down. Note that tl, t2, . . . tx indicate the time of the phase switching interval.

Next, the document image erasing means will be explained.

15 and 16, a guide shaft 130 is provided along the lamp 4 in a portion of the first carriage 411 where the light of the lamp 4 is blocked. This guide shaft 130 has a spot light source 1 as a means for instructing the erasing range of the document.
31, the light receiving section 132 is integrally movably attached to the crotch IJ. This spot light source 131 and the light receiving section 132 are the 16th
As shown in the figure (a>(b), the spot light ITi 131
is arranged so that its optical axis is perpendicular to the document table 2, and the light receiving section 13
2, its front axis is the surface of the document table 2, and the spot light source 13
The optical axis of the optical system 1 is inclined so as to intersect with the optical axis of the optical system 1. Among these, the spot light [131 is a light emitting device 131a such as a light emitting diode or a lamp, and the light emitting element 1
Lens 1 that guides the light generated from 31a toward the document table 2
31b, and the light receiving section 132 is composed of a light receiving element 132a.
, a lens 132b that guides reflected light from the document table 2 to the light receiving element 132a. The light emitting element 13
The lighting signal 1a is supplied from the main processor group 71, and the output signal of the light receiving element 132a is supplied to the main processor group 71. The light emitted from the spot light ill 131 is shown in FIG. 16(a).
As shown in FIG. 2, a spot light beam having a diameter d is irradiated onto the document table 2-1, and this spot light has a brightness that can pass through the document set on the document table 2 and having the thickness of, for example, a postcard.

In addition, the light source 131 J5 and the light receiving section 132 are connected to the timing belt (
Toothed belt>13! Connected to I.

This timing belt 134 is connected to a pulley 136 and a driven pulley 13 connected to the rotating shaft of a pulse motor 135.
7 and the hook have been passed. Therefore, the pulse motor 1
35 is rotated, the spot light source 131 and the light receiving section 132 are moved in a direction perpendicular to the scanning direction of the first carriage 411. In addition, the first carriage 41 located at the end of the pulse motor 135 of the guide shaft 130
1 is provided with a spot light source 131 and a position sensor 138 consisting of a microswitch that detects the initial position of the light receiving section 132. For example, spot light 11113
1 is moved, first the spot light source 131 is moved to the position I.
f f? The initial position is detected by contacting the sensor 138.

Next, a method for specifying the erasing range of a document using the spot light source 131 will be explained using FIGS. 17 to 19. When specifying the erasure range of the original (^), the original G is set with the copy side facing up on the fixed scale 22 side, as shown in FIG. 17. In this state, when the operation keys 308 to 30d are operated, , the spot light source is moved with the light emitting element 131a turned on. That is, when the operation keys 30b and 30d are pressed, the motor 33 is driven and the first carriage 411 and the spot light source 131 are moved in the scanning direction (as shown in FIG. 17). (in the direction of arrow X).
When the operation keys 30a and 30G are pressed, the motor 135 is driven and the sub-box I/light source 131 is moved in a direction perpendicular to the scanning direction (in the direction of arrow X in FIG. 17).

The operator operates the operation keys 30a-30C1 while visually observing the light transmitted through the original G, and moves the spotlight to the point S1 on the original G shown in FIG. 18(a), for example. i2 position designation key 30 (Press 3.

Then, the coordinate position specified by this Sl is stored in the main processor group 71 shown in FIG. Similarly, when the spot light is moved to 82 points on the document G and the position w designation key 30e is pressed, the position of the 82 points is stored in the main sensor group 71. The position of this spot light can be detected, for example, by counting the number of drive pulses of the pulse motor 33.135. After that, when the erasure range designation key 30f is pressed, Sl, 8
A rectangular area (indicated by diagonal lines) with two diagonal points is designated as the erasing range. Also, as shown in FIG. 18(b), if you specify points 83 and 84 on the original G and press the erase range designation key 300, the area other than the square with the diagonal points of points 83 and 84 will be set as the erase range. It is specified.

In this way, each time the erasure range specification keys 30f and 3oQ are pressed, the main processor group 71 performs calculations based on the positions of the two specified points and the copy magnification, and the memory 14
0, a high level signal 1111+ is stored in the erase range portion, and a low level signal II OII is stored in the other portions. That is, this memory 140 has, for example, R A M 1. whose capacity in each column direction is approximately equal to the moving distance of the light source 131 to the subbox 1 in the X direction divided by the position resolution in the y and X directions. : J:, and according to the data supplied from the main processor group 71, the
As shown in Figure 9(a), and in the case of Figure 18(b), as shown in Figure 19(b), a high level signal is sent to the address corresponding to the shaded area, and a low level signal is sent to the address other than the blank area. Level signals are stored.

The original @G, whose erasing range has been designated as described above, is reversed in the X direction shown in FIG. be done. Therefore, in this state, the original image and the erased data stored in the memory 140 are associated with each other.

On the other hand, as shown in FIG. 20, an erasing array 150 serving as erasing means is provided close to the photosensitive drum 10, for example, between the charger 11 and the exposure section ph. As shown in FIGS. 21 and 22, this erasing array 150 has a plurality of light shielding cells 151 arranged in a direction perpendicular to the rotational direction of the photoreceptor drum 10, and each light shielding cell 151 has a plurality of light shielding cells 151 arranged therein in a direction perpendicular to the rotational direction of the photoreceptor drum 10. As shown in FIGS. 23(a) and 23(b), a light emitting element 152 made of, for example, a light emitting diode is installed. The light from the light emitting element 152 is transmitted to the photoreceptor drum 10.
A lens 153 is provided on the surface of the lens 153 to allow light to enter.

The number of light emitting elements arranged in the erasing array 150 matches, for example, the capacity 1 of the memory 140 in the 1 direction. Here, yt;till between the light emitting elements 152 phase N is P
If the number is N, the total length of the erase array 7750 is Q=NXP.

The erase array 150 is driven by the array driver 160 described above. This array drive section 160 is the 24th
As shown in the figure, there is a shift register 161 having the same number of bits as the number of bits in the column direction of the memory 140, a store register 162 that holds the contents of this shift register 161, and each output signal of this shift register 162. The switch circuit 164 includes a plurality of switch elements 163 that are controlled on and off by the movable contact pieces 163 a 1 of these switch elements 163. is grounded, and the fixed contacts 163b are connected to each cathode of the light emitting elements 152 constituting the erasing array 150, respectively. The anode of each of these light emitting elements 152 is connected to the power supply VCC through a current limiting resistor R, respectively.

After specifying the erase range of the original as described above, when the original cover 11 is closed and the copy key 301 is pressed, the first carriage 411 and the photosensitive drum 10 are operated, and the memory 140 is moved in the row direction. One column of data is sequentially read out (shown in FIG. 19). This read data D1 is transferred to the shift register 161 of the array driving section 160 in response to the clock signal CLK.

After one column of data is transferred to the shift register 161, the charged portion of the photoreceptor drum 10 is transferred to the erase array 15.
When it reaches 0, the main processor group 71 outputs a latch signal QLTH, and in response to this signal, shift 1 to
The data stored in the lnosister 161 is stored in the store register 162.
supplied to That is, since the erasing array 150 is disposed between the charger 11 and the exposure section Ph, the memory 1
For example, if the angle between the erasing array 150 and the exposure section Ph is 01, and the photoreceptor drum l\10 is rotating at each speed, the data for one column outputted by 40 is θ1/α.
The output timing of the latch signal LT)-1 is controlled so that it is supplied to the store register 162 before LT).

Each switch element 163 of the switch circuit 164 is controlled by the output signal of the store register 162. That is, when the output level of the store register 162 is high level, it is turned on, and when it is low level, it is turned off. As a result, the light emitting elements 152 connected to each switch element 163 are turned on when the switch element 163 is on, and are turned off when the switch element 163 is off. Therefore, among the charged parts of the photoreceptor drum 10, the part where the light emitting element 152 is turned on is charge-free, and even if the charge-free part is exposed afterwards, no electrostatic latent image is formed, and the original image is not erased. It means that it was done. Similarly, the data in the memory 140 is read out one column at a time, and the image is erased.

Next, the gist of the invention will be explained. In this embodiment, when specifying the erase range of the original, the operation key 30 is pressed.
When any one of a to 30d is operated, the document set position is first detected. That is, Fig. 1 (
As shown in a), the document table 2 is made larger by an extra portion ya than the horizontal length yg of the maximum document size A3, and when an A3 document G is placed on the fixed scale 21 side, ya This is done so that a gap will be created. To detect the set position of the original, the spot light source 131 and the light receiving Pi 1132 are moved to this surplus portion ya, and the light receiving portion 13
Depending on the presence or absence of spot light incident on 2, it is detected whether the original is set in the correct position. Furthermore, if the setting of the document is not detected due to this movement, the spot light i[1131 and the light receiving section 132 are moved by a width of x1 in the X direction in the surplus section ya, and the spot light incident on the light receiving section 132 is moved. Whether or not the original is set in the correct position is detected based on the presence or absence of the document. This detection by movement in the X direction is performed for a predetermined period of time until the setting of the original is detected.

Next, the above document detection operation will be explained using FIG. 2. When any of the operation keys 30a to 30d is operated with a document set on the document table 2, the main processor group 71 activates the spot light source 131 and the light receiving section 132 in step STI as shown in FIG. 1(a). The light emitting element 131a is moved at high speed to the surplus part ya, and the light emitting element 131a is turned on in this surplus part ya. After this, in step ST2, the light receiving element 13 in the light receiving section 132
It is determined whether or not 2a is in the on state. That is, when the original G is set on the fixed scale 21 side as shown in FIG. 1(a), or when the original G is set on the lower side of the fixed scale 22 as shown in FIG. 1(C). If it is, the spot light will not be incident on the light receiving section 132.
The light receiving element 132a is in an off state. Therefore, in this case, control is transferred to step ST3, and in step ST3, the main processor group 71 drives the motor 135 to control the spotlight II.
13111'3. and moves the light receiving section 132 by a width of x1 in the X direction. During this movement, the light-emitting cord 131a is lit, and it is determined whether the light-receiving element 132a in the light-receiving section 132 is in the on state. That is, one manuscript G is shown in Fig. 1 (
As shown in a), when it is set on the fixed scale 21 side, the light receiving element 132a is in an off state because no spot light is incident on the light receiving section 132.

Therefore, if this state has elapsed for a predetermined period of time, the control moves to step ST4, and in step ST4, the buzzer 170 sounds to notify that the document is set in the wrong position. Thereafter, the control is transferred to step STs again, and the buzzer 170 continues to sound until the document G is reset to the fixed scale 22 side, as shown in FIG. 1(b).

On the other hand, if the original is set on the fixed scale 22 side as shown in FIG.
If the original G is set on the lower side of the fixed scale 22 as shown in FIG. Since the light is incident on the light receiving element 132a, the light receiving element 132a is turned on. Therefore, the control is transferred from step ST6 to step ST6, and in this step STs, the above-described operation of specifying the erasure range is performed. After the erasing range designation operation is completed, when the original is set on the fixed scale 21 side and the copy key 301 is operated, control is transferred to step ST7, and the above-mentioned erasing copying operation is performed. When this erasure copying operation is completed, the process is completed.

According to the embodiment described in L, an extra portion ya is provided on the document table 2 so as to be slightly larger than the maximum document size, and when any of the operation keys 30a to 30d is operated when specifying the erasure range, the above-mentioned The spot light source 131 and the light receiving section 132 are moved to the surplus part ya, or the spot light source 131 and the light receiving part 132 are moved in the X direction in the surplus part ya, and the set position of the document is detected. Therefore, it is possible to prevent the user from specifying the erasing range while the original is set in the wrong position.
It is also possible to prevent mistakes in copying the original.

Also, the operation keys 30a to 30d are used to detect the set position of the original.
It is easy to operate because it is automatically performed by operating any one of them.

Furthermore, when detecting the set position of the original, operation keys 30a to 3 are pressed.
0 (spot light source 131, light receiving section 13 according to the operation of j)
2 is moved at high speed, it does not affect the operation of specifying the erasing range and has excellent operability.

Note that this invention is not limited to the above embodiments.

For example, the arrangement position of the erasing array 150 is not limited to that shown in FIG. 20, but as shown in FIG.
It is also possible to configure a structure in which the electrostatic latent image formed by the electrostatic latent image is erased according to a designation.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention Song 1] As described in detail above, according to the present invention, it is possible to provide an image forming apparatus capable of detecting whether or not a document is correctly placed on the document table.

[Brief explanation of drawings]

The drawings show an embodiment of the image forming apparatus according to the present invention, and FIG. 1 is a plan view of the main parts for explaining the operation of detecting the document setting position, and FIG. 2 is a plan view showing the document setting position. Figures 3 and 4 shown to explain the detection operation show the configuration of the image forming apparatus. FIG. 6 is a plan view showing the configuration of the operation panel, FIG. 6 is a perspective view showing the configuration of the drive unit, and FIG.
The figure is a perspective view schematically showing the drive mechanism of the optical system, Figure 8 is a perspective view schematically showing the drive mechanism of the pointer, Figure 9 is a configuration diagram showing the overall control circuit, and Figure 10 is the main A configuration diagram of the processor group, FIG. 11 is a configuration diagram of the first sub-processor group, FIG. 12 is a configuration diagram of the second sub-processor group, FIG. 13 is a schematic configuration diagram showing the control circuit of the pulse motor, and FIG. 14 15 is a diagram showing a method for controlling the speed of a pulse motor, FIG. 15 is a perspective view of a spot light source, and FIG. 16 is a perspective view of main parts.
Figures (a) and (b) are side sectional views of the main parts of the spot light source, respectively. FIG. 19 is a diagram shown to explain the contents of the memory, FIG. 20 is a sectional side view of the main part showing the arrangement of the erasing array, and FIGS. 21 and 22 show the relationship between the erasing array and the photosensitive drum, respectively. Fig. 21 is a perspective view showing only the main parts, Fig. 22 is a front view showing only the main parts, and Fig. 23 is a perspective view showing only the main parts.
The figures show the configuration of the erasing array, where (a) is a side sectional view, (b) is a partially cutaway front view, and Figure 24 is a circuit showing the configuration of the array drive section. 25 are side sectional views of essential parts showing other examples of arrangement of the erasing array. DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photosensitive drum, 30...Operation panel, 30a-30d...Operation keys, 30e...Position specification key, 30f, 300...
・Erase range specification key, 71...main processor group,
131... Spot light source, 132... Light receiving section, 13
5... Motor, 140... Memory, 150... Erase array, 160... Array drive section, P... Paper,
Ph...Exposed part. Applicant's agent Patent attorney Takehiko Suzue (a) Figure 1 (b) (C) District 2 Figure 3 (a) Figure 17 Figure 18 (a) Figure 18 (b) (a) (b) Fig. 19 Fig. 20 Fig. 21 Fig. 22 Cause (a) (b) Fig. 23, 160 Section 24 Fig. 25

Claims (3)

[Claims] (1) In an image forming apparatus that optically scans a document placed on a document table by a scanning means and transfers an image corresponding to the image of the document to a transfer material, the document table is larger than the maximum document size. first and second document setting standards provided at both ends of the scanning device; an indicating device provided in the scanning device for instructing a predetermined range of the document set on the second document setting reference side using transmitted light; an erasing means for erasing an image corresponding to the designated range; a detecting means movable together with the indicating means; moving the detecting means near the second document setting reference; An image forming apparatus comprising: a control means for detecting a set position of a document by moving the detection means along a set reference. (2) The indicating means is comprised of a light emitting element that is movable in a direction perpendicular to the moving direction of the scanning means and irradiates the document with a spot light, and the detecting means is comprised of a light receiving element that detects the spot light. An image forming apparatus according to claim 1. (3) The image forming apparatus according to claim 1, wherein the control means drives the notification means when the control means determines that no document is set according to the output signal of the detection means. .