JPS62103666A - Image forming device - Google Patents

Abstract

PURPOSE:To detect whether an original is set in a correct position or not after designating an erase range by providing a scanning means with a spot light source and a light receiving part driven together with the spot light source. CONSTITUTION:When a copy key 301 is operated after designating the erase range of the original, the set position of the original is detected to detect whether the original is reset from the side of a fixed scale 22 to a fixed scale 2, or not. That is, an original platen 2 is made wider than a length yg in the transverse direction of a maximum original size A3 by an excess part ya, and the gap ya is generated when the original G of A3 size is set to the side of the fixed scale 21. Meanwhile, a black dark part 171 is provided in the center of a part, which faces the excess part ya, of an original cover 11. In case of detection of the set position of the original, a spot light source 131 and a light receiving part 132 are moved to the excess part ya corresponding to the dark part 171 of the original cover 11 when the original cover 11 is closed, and it is detected whether the original is set in the correct position or not there in accordance with presence or absence of the spot light incident on the light receiving part 132.

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 its problems]

In general, an electronic copying machine has 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, for example, when specifying the erasing range of a document, the document is set on one side of the document table, and when copying, the document is placed on the other side of the document table. is being developed.

In such a copying machine, if you specify the erasing range of the original on one end of the original platen and then do not set the original on the other end of the original platen, you will not be able to obtain the desired copy image. Therefore, it would be convenient in practice if such document setting errors could be prevented.

[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 spotlight to specify an erasing range, and irradiates a photoreceptor drum with light corresponding to the designated erasing range to form an electrostatic latent image. Alternatively, an image is formed by erasing the charge, and in particular, the scanning means is provided with a spot light source that generates the spot light and a light receiving section that is driven together with the spot light source, and the erasing range is determined by the spot light source and the light receiving section. After designation, it is detected whether 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 copy opening main body 1. Fixed scales 21 and 22 are provided at both ends of the document table 2 to serve as a reference for setting the document.
A document cover 11 and a work table 12, which can be opened and closed, are provided near the. The original placed on the original platen 2 is exposed by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, 7 being reciprocated in the direction of arrow a along the lower surface of the original platen 2. It is meant to be scanned. In this case, mirror 6.7 is configured to maintain the light exposure length.
The mirror 5 is moved at a speed of 172. 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, and then passes through the variable magnification lens block 8.
Further, the light is reflected by mirror 9 and guided to photoreceptor drum 10, so that an image of the document is formed on the surface of photoreceptor drum 10.

The photosensitive drum 10 is rotated in the direction of arrow C in the figure, and first, the surface thereof is charged by the charging device 11. Thereafter, the i-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 (transfer material) P is taken out one by one from the selected upper paper feed cassette 13 or lower paper feed cassette 14 by the delivery roller 15 or 16, and the taken out paper is taken out from the paper guide path 17 or 18 and is guided to a pair of registration rollers 19, and guided to a transfer section by this pair of registration rollers 19. Here, the paper feed cassettes 13 and 14 are removably provided at the lower right end of the main body 1, and one of them can be selected from an operation panel to be described later.

The cassette size of each of the paper feed cassettes 13 and 14 is detected by a cassette size detection switch 601 and 602, respectively. The cassette size detection switches 601 and 602 are composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

The paper P sent to the transfer section is brought into close contact with the surface of the photoreceptor drum 10 at the transfer charger 20, and
The toner image on the photoreceptor drum 10 is transferred by the action of 0. The transferred paper P is electrostatically peeled off from the photosensitive drum 10 by the action of a peeling charger 21, and is sent by a 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 fixed paper P is discharged to a tray 25 outside the main body 1 by a pair of paper discharge rollers 24 . Further, the photoreceptor drum 10 after the transfer is transferred to a charger 2 for removing static electricity.
6, residual toner on the surface is removed by a cleaner 27, and afterimages are erased by a static elimination lamp 28, so that the initial state is restored. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

FIG. 5 shows an operation panel 30 provided on the main body 1. 301 is a copy key for instructing the start of copying; 302
is a numeric keypad for setting the number of copies, etc., 303 is a display unit that displays the operating status of each part and paper jams, etc., 304 is a cassette selection key for selecting the upper and lower paper feed cassettes 13 and 14, and 30s is a selected key. A cassette display section for displaying the cassette, 306 a magnification setting key for setting the enlargement and reduction magnification of copies in a predetermined relationship, 307 a zoom key for steplessly setting the enlargement and reduction magnification, and 30B for displaying the set magnification. A display section, 309 is a density setting section for setting the copy density, 30a, 30b, 30c, and 30d are operation keys for moving a spot light source indicating the erasing position of the original, which will be described later, and 30e is for inputting the coordinate position indicated by the spot light source. The position designation keys 30f, 30 and 1 are erasure range designation keys for designating the erasure range at a designated position, respectively.

FIG. 6 shows an example of the drive source configuration of each drive section of the copying machine configured as described above, and is composed of the following motors. That is, 31 is a lens motor, which is a motor for moving the position of the lens block 8 for performing magnification change. 32 is a mirror motor;
This is a motor for changing the distance (optical path length) between the mirror 5 and the mirror 6.7 for changing the magnification.

A scanning motor 33 is a motor for moving the exposure lamp 4, the mirror 5, and the mirror 6.7 for scanning the original. A shutter motor 34 is a motor for moving a shutter (not shown) for adjusting the charging width of 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. Reference numeral 37 denotes 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 15, 16
This is a motor for driving. A paper feeding motor 39 is a motor for driving the registration roller pair 19. A fan motor 40 is a motor for driving the cooling 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 41, and the mirror 6.7 is supported by a second carriage 422, and these carriages 411 and 412 are guided by guide rails 42r and 422 in the direction of arrow a. It is said that it can move freely in parallel. Also, 4
The phase pulse motor 33 drives a pulley 43. An endless belt 45 is stretched between this pulley 43 and the idle pulley 44, and this belt 45
The first carriage 41 supports the mirror 5 in the middle of the ! One end is fixed. On the other hand, a rail 422 is attached to the guide portion 46 of the second carriage 422 that supports the mirror 6.7.
Two pulleys 47.47 are rotatably provided apart from each other in the axial direction, and a wire 48 is stretched between these pulleys 47.47. One end of this wire 48 is fixed to a fixed part 49, and the other end is fixed to the fixed part 49 via a coil spring 50. In addition, the wire 4
One end of a first carriage 411 is fixed to the middle part of 8. Therefore, by rotating the pulse motor 33, the belt 45 rotates and the first carriage 411
is moved, and the second carriage 422 is also moved accordingly.

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, 412 is controlled by switching 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 304
Bind the paper size specified by <pxSpy>,
If the copy magnification specified by the magnification setting keys 306 and 307 is K, the copyable range (x, y) is rx-P
x/Kl.

It becomes "y-Py/K". 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 the distance between the first carriages 41! Scale 53 provided on the top surface of
and the distance between the fixed scales 21.

As shown in FIG. 8, the above-mentioned pointers 51.
55 via a spring 56. The pulley 55 is rotated by a motor 58, and by driving the motor 58 in accordance with the bundled copyable range in the X direction, the distance between the pointers 51 and 52 is changed. It is now possible to

Further, the first carriage 411 is moved to a predetermined position (home position according to the magnification) by driving the motor 33 according to the paper size and magnification. When the copy key 30s 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.

FIG. 9 shows the overall control circuit.

The main processor group 71 includes a high-voltage transformer 76 that detects inputs from the operation panel 30 and input devices 75 such as various switches and sensors, such as the cassette size detection switches 60r and 602, and drives the various chargers.
the static elimination lamp 28, the blade solenoid 27a1 of the cleaner 27, the heater 23a of the fixing roller pair 23,
The exposure lamp 4 and each of the motors 31 to 40.5
8 etc. to perform the above-mentioned copying operation,
Spot light source 131, light receiving section 132, pulse motor 13
5, memory 140, erase array 150, array drive unit 1
60, controlling a buzzer 170 etc. as a notification means,
It detects the set position of the original and performs operations to erase unnecessary parts of the original. In addition, the spot light 113
1. Light receiving section 132, pulse motor 135, erasing array 1
50, array drive unit 160, buzzer 170, memory 14
0 will be described later.

Among the above 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 the pulse motor driver 79, and the motors 36, 39, 38, 58
is controlled by the second sub-processor group 73 via the pulse motor driver 80. Further, the exposure lamp 4 is controlled by the main processor group 71 via the lamp regulator 81, 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 72.7
Drive and stop commands for each motor are sent to the first motor. Second
From sub-processor group 72 and 73 to main processor group 7
1, a status signal indicating the driving or stopping state of each motor is sent. The first sub-processor group 72 also includes a position sensor 83 that detects each initial position of the motors 31 to 34.
Location information has been entered from.

FIG. 10 shows an example of the configuration of the main processor group 71. One-chip microcomputer 91 (hereinafter referred to as
The microcomputer (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 boat 93.
A size switch for detecting paper size and its respective inputs are connected to the input/output port 4, and a copying condition setting switch and its respective inputs are connected to the input/output port 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. When a set value is set from the microcomputer 101, the timer 102 starts counting reference clock pulses based on the setting value. When the timer 102 has counted out, the end pulse is sent to the microcomputer 101. It is configured to output to the interrupt line. The microcomputer 101 also includes the position sensor 8.
Position information from 3 is input, and input/output boats 103 and 104 are connected. The input/output boat 104 is connected to the motors 31 to 34.135 via the pulse motor driver 79. still,
The input/output board 103 is used, for example, when outputting status signals of each pulse motor to the main processor group 71.

FIG. 12 shows the configuration of the second sub-processor group 73. The microcomputer 111 is connected to the main processor group 71
is connected to. The programmable interval 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 reference clock pulses based on it, and when the count is out, it starts counting the end pulse. It is designed to be output. This termination pulse is latched by the latch circuit 113, and its output is supplied to the interrupt line and input/output board input line of the microcomputer 111. Further, an input/output boat 114 is connected to the microcomputer 111, and this input/output boat 114 is connected to the pulse motor driver 8.
Motors 36.38.39.58 are connected via 0.

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 driver 79.80 in FIG. 9) is connected to the pulse motor driver 122.
6.38.39.58.135) windings A and 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 long at the beginning;
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 1. t1, 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 is provided with a spot light [1
31, a light receiving section 132 is provided integrally and movably. The spot light source 131 and the light receiving section 132 are arranged so that the optical axis of the spot light 5i131 is orthogonal to the document table 2, as shown in FIGS. The spot light source 131 is inclined so as to intersect with the optical axis of the spot light source 131 at the surface portion of the spot light source 131 . Among these, the spot light source 131 includes a light emitting element 131a such as a light emitting diode or a lamp, and this light emitting element 131a.
A lens 131b that guides the light generated by the
The light receiving section 132 includes a light receiving element 132a and a lens 132b that guides reflected light from the document table 2 to the light receiving element 132a. A lighting signal for the light emitting element 131a is supplied from the main processor group 71,
The output signal of the light receiving element 132a is sent to the main processor group 71.
is being supplied to.

Note that the light emitted from the spot light source 131 is the 16th light source.
As shown in Figure (a), a spot light with a diameter d is irradiated onto the document table 2, and this spot light has a brightness that can pass through the document set on the document table 2, for example, the thickness of a postcard. .

Further, the spot light source 131 and the light receiving section 132 are connected to a timing belt (toothed belt) 134 disposed along the guide shaft 130.

This timing belt 134 is passed between a pulley 136 provided on the rotating shaft of a pulse motor 135 and a driven pulley 137. Therefore, by rotating the pulse motor 135, 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. Also, the first carriage 411 located at the end of the guide shaft 130 on the pulse motor 135 side has a spot light +11131. A position sensor 138 consisting of a microswitch that detects the initial position of the light receiving section 132 is provided. For example, when the spot light source 131 is moved, first the spot light source 131 is moved to the position sensor 1.
38 and the initial position is detected.

Next, using FIGS. 17 to 19, the spot light w
A method of specifying an erasing range of a document using 131 will be explained. When specifying the erasing range of a document, the document G is set on the fixed scale 22 side with the copy side facing up, as shown in FIG. In this state, operation key 3
When 08 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
The carriage 411 and the spot light source 131 are moved in the scanning direction (arrow y direction shown in FIG. 17). Further, when the operation keys 30a and 30C are pressed, the motor 135 is driven, and the spot light +1i131 is moved in the direction perpendicular to the scanning direction (the direction of the arrow X shown in FIG. 17). The operator presses the operation key 3 while visually observing the spot light transmitted through the document G.
08 to 30d to move the spotlight to, for example, the 81 point on the document G shown in FIG. Similarly, when the position designation key 30e is pressed with the spotlight moved to 82 points on the document G, the positions of the 82 points are stored in the main processor group 71 shown in the figure. The position of this spot light can be detected, for example, by counting the number of driving pulses of the pulse motor 33.135.After this,
When the erasure range designation key 30f is pressed, a rectangular area (indicated by diagonal lines) having diagonal points 81 and 82 is designated as the erasure range, as shown in FIG.
As shown in figure (b), specify points 83 and 84 of document G,
When the erasure range designation key 30Q is pressed, the area other than the square with 83.84 points as diagonal points is designated as the erasure range. In this way, when the erasure range designation keys 30f and 30Q are pressed, the main processor group 71 performs calculations based on the positions of the two designated points and the copy magnification, and the memory 14
0, a high level signal IT 11T is stored in the erase range portion, and a low level signal It OI+ is stored in the other portions. That is, this memory 140 is constituted by, for example, a RAM whose capacity in each column direction is approximately equal to the moving distance of the spot light source 131 in the X direction divided by the position resolution in the y force direction. , in the case of Fig. 18(a), as shown in factor 19 (a), and in the case of Fig. 18(b), as shown in Fig. 19(
As shown in b), a high level signal is stored at the address corresponding to the shaded area, and a low level signal is stored at the other addresses.

The original G, whose erasure range has been designated as described above, is reversed in the y direction shown in FIG. 17, and set on the fixed scale 21 side to be copied with the copy side facing down. Ru. 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. A light emitting element 152 made of, for example, a light emitting diode as shown in FIGS. 23(a) and 23(b) is provided.

Furthermore, a lens 153 is provided in the opening of each cell 151 facing the photoreceptor drum 10 to focus the light from the light emitting element 152 onto the surface of the photoreceptor drum 10 . The number of light emitting elements arranged in this erasing array 150 matches, for example, the capacity of the memory 140 in the column direction. Here, if the distance between the light emitting elements 152 is P and the number is N, the total length of the erasing array 150 is Q-NXP.

The erase array 150 is driven by the array driver 160 described above. As shown in FIG. 24, this array driving section 160 includes a shift register 161 having the same number of bits as the number of bits in the column direction of the memory 140, and a store register 16 in which the contents of this shift register 161 are held.
2. It is constituted by a switch circuit 164 consisting of a plurality of switch elements 163 that are controlled on and off by each output signal of the store register 162. The movable contacts 163a of these switch elements 163 are grounded, and the fixed contacts 163b are grounded. Each of the light emitting elements 152 constituting the erasing array 150 is connected to each cathode. The anodes of each of these light emitting elements 152 are connected to the power source CC through current limiting resistors 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 1o are operated, and the memory 140 is read in the row direction. One column of data is sequentially read out (as 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 the value reaches 0, the main processor group 71 outputs a latch signal LTH, and the data stored in the shift register 161 is supplied to the store register 162 in response to this signal. In other words, erasure.

Since the array 150 is disposed between the charger 11 and the exposure section ph, one column of data output from the memory 140 has an angle of θ1 between the erasing array 150 and the exposure section Ph, and the photosensitive Assuming that the body drum 10 is rotating at an angular velocity ω, the output timing of the latch signal LTH is controlled so that it is supplied to the store register 162 before θ1/ω.

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 completely neutralized, and even if the statically removed part is exposed afterwards, an electrostatic latent image is not formed, and the original image cannot be erased. It has been done. Thereafter, the data in the memory 140 is read out one column at a time in the same manner, and the image is erased.

Next, the gist of the invention will be explained. In this embodiment, after specifying the erase range of the original, the copy key 30 is pressed.
When you operate 1, first the position of the original is detected,
It is detected whether or not the original is set on the fixed scale 21 from the fixed scale 22 side.

That is, as shown in FIG. 1(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 an A3 document G is set on the fixed scale 21 side. In this case, a gap of ya is created. On the other hand, as shown in FIG. 1(b), a dark portion 171 made of black is provided at the center of the portion facing the surplus portion ya of the document cover 11. As shown in FIG. The document set position is detected when the document cover 11 is closed and the spot light source 1 is detected.
31 and the light receiving section 132 in the dark area 1 of the document cover 11.
The document is moved to the surplus portion ya corresponding to 71, and at this position, it is detected whether the document is set in the correct position depending on the presence or absence of spot light incident on the light receiving section 132.

Next, the above document detection operation will be explained using FIG. 2. When the operation keys 30a to 30d of the operation panel 3o are operated, the main processor group 71 is placed in a document erasure range specification mode. In this mode, step S
king! In response to the operation of the operation keys 3Qa to 30d, the above-mentioned erasing range designation operation is performed, and then step S
At T2, it is determined whether the copy key 301 of the operation panel 30 has been operated. As a result, the operation key 301
When is operated, in step STs, the spot light source 131 and the light receiving section 132 are moved at high speed to the longitudinal center of the surplus part ya shown in FIG. Element 131a is lit.

After that, in step ST4, it is determined whether the light receiving element 132a in the light receiving section 132 is in an on state. That is, the document G is fixed scale 2 as shown in FIG. 1(C).
If it remains set to the 2 side, the spot light source 131
The irradiated light is reflected by the document G and enters the light receiving section 132. Therefore, the light receiving element 132a is turned on, and in this case, the control is shifted to step STs. In step STs, the buzzer 170 sounds to notify that the document is set in the wrong position. After that, the control is transferred to step ST4 again, and the document G is placed on the fixed scale 2 as shown in FIG. 1(a).
The buzzer 170 continues to sound until it is reset to the 1 side.

On the other hand, when the original G is set on the fixed scale 21 side as shown in FIG. Therefore, the light receiving element 132
a is in an off state. Therefore, in this case,
Control is transferred from step ST4 to step STs,
In this step STs, the first carriage 411 is moved, for example, toward the fixed scale 21 from the surplus portion ya. Then, the first carriage 411 is connected to the fixed scale 2.
When it returns to the 1 side, the above-described erasure copying operation is executed in step ST7.

According to the embodiment described above, the surplus portion ya is provided on the document table 2 so as to be slightly larger than the maximum original size, and the dark portion 171 is provided on the document cover 11 corresponding to the surplus portion ya, and after specifying the erasing range, When the copy key 301 is operated, the spot light source 131 and the light receiving section 132 are first moved to the surplus area ya to detect whether or not the original has been set again. Therefore, it is possible to prevent the copying operation from being performed while the original is set in the wrong position, thereby making it possible to prevent copying errors.

In addition, since the document set position is automatically detected by operating the copy key 301, operability is good.

Furthermore, when detecting the set position of the original, the spot light source 131 and the light receiving section 132 are moved at high speed according to the operation of the copy key 301, so that the copying operation is not affected and the operability is excellent. .

In addition, since the document cover 11 is provided with a dark area 171,
With the document cover 11 closed, it is possible to detect the document set position with high accuracy.

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] 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 set 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(a) is a plan view of the main part shown for explaining the surplus part of the document table, and FIG. 1(b) is a plan view of the main part of the document table. Exterior perspective view shown to explain the dark part provided on the cover, the same figure (
C) is a plan view of the main parts shown to explain the operation of detecting the set position of the original, FIG. 2 is a diagram shown to explain the operation of detecting the set position of the original, and FIGS. 3 and 4 are the image forming apparatus Fig. 3 is an external perspective view, Fig. 4 is a side sectional view, Fig. 5 is a plan view showing the structure of the operation panel, and Fig. 6 is a perspective view showing the structure of the drive section. FIG. 7 is a perspective view schematically showing the drive mechanism of the optical system, FIG. 8 is a perspective view schematically showing the drive mechanism of the pointer, FIG. 9 is a configuration diagram showing the overall control circuit, and FIG. 11 is a configuration diagram of the first sub-processor group, FIG. 12 is a configuration diagram of the second sub-processor group, and FIG. 13 is a schematic configuration diagram showing a pulse motor control circuit. Fig. 14 is a diagram shown to explain the speed control method of the pulse motor, Fig. 15 is a perspective view of the main part showing the spot light source, and Fig. 16 (a) (b).
17 is a side sectional view of the main part showing the spot light source, respectively.
FIG. 18 and FIG.
9 is a diagram shown to explain the contents of the memory, FIG. 20 is a side sectional view of the main part showing the arrangement of the erase array, and FIG.
Fig. 22 shows the relationship between the erasing array and the photosensitive drum. 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 diagram of the erasing array. Fig. 24 is a circuit diagram showing the structure of the array drive unit, and Fig. 25 is a diagram showing the structure of the array drive unit. 1 is a side sectional view of main parts showing another arrangement example of the erasing array. 1... Main body, 2... Document table, 10... Photosensitive drum, 30... Operation panel, 30a to 30d. ...Operation key, 30e...Position specification key, 30f, 3C1...
・Erase range specification key, 71...main processor group,
131... Spot light source, 132... Light receiving section, 14
0...Memory, 150...Erase array, 160...
- Array drive unit, 170...buzzer, 171...dark area, P...paper, ph...exposure unit. Applicant's representative Patent attorney Takehiko Suzue 1rE1 Figure (a) Figure 111 (b) Figure 1 (C) Figure 2 Figure 3 Figure 15 Figure 16 (a) Figure 16 (b) Figure 17 Figure 18 Figure (a) 18th v! J (b) (a) (b) Fig. 19 1! Fig. 20 @ 25viJ Fig. 21 (a) (b) Boat 0 1 Bow O Fig. 24

Claims (4)

[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 detection means movable together with the instruction means; an operation means for instructing the start of image formation; an image forming apparatus comprising: a control means for moving the document near a second document setting reference and detecting the document setting position; (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 document table is provided with a document table cover that is openable and closable and has a dark area near the second document setting reference;
2. The image forming apparatus according to claim 1, wherein the detecting means is moved to a position facing the dark area in response to an operation of an operating means. (4) When the control means determines that the document set position is incorrect based on the output signal of the detection means, the control means drives the notification means.
The image forming apparatus described in .