JPS6271975A - Image forming device - Google Patents

Abstract

PURPOSE:To detect whether an original is set up on a correct position or not by forming an original platen slightly larger than the maximum size of originals, setting up fixed scales on both the end parts of the original platen, and at the specification of an erasing range, moving a photodetecting part to the side of a prescribed fixed scale out of the fixed scale. CONSTITUTION:When any one of operation keys 30a-30d is operated at the specification of an erasing range of an original, the setting position of the original is detected at first. Namely, the original platen 2 is formed larger than the horizontal length yg of the maximum original size A3 by an excess part ya, and when an original G of size A3 is set up on the fixed scale 21 side, a gap ya is generated. To detect the setting position of the original, a spot light source 131 and the photodetecting part 132 are moved to the excess part ya, and whether the original is set up on a correct position or not is detected in accordance with the existence of spot light made incident upon the photodetecting 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]

Generally, an electronic copying machine has a 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, it will be possible to prevent copying errors, 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 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.In particular, the document table is made slightly larger than the maximum original size, and fixed scales are provided at both ends of the document table. The scanner moves to a predetermined one of the fixed scales and detects whether or not the document 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 top surface of the copying machine 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.
It is moved at 1/2 the speed of the mirror 5. 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 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 viewed as the surface of the photoreceptor drum 10 at the transfer charger 20, and the charger 20
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 snow removing lamp 28, thereby returning to the initial state. Two cooling fans are used to prevent the temperature inside the main body 1 from rising.

FIG. 5 shows an operation panel 3o provided on the main body 1. 30r is a copy key for commanding 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 section and paper jams; 304 is a cassette selection key for selecting the upper and lower paper feed cassettes 13 and 14; 305 is a selected key. A cassette display section for displaying the cassette, 306 a magnification setting key for setting copy enlargement and reduction magnification in a predetermined relationship, 307 a zoom key for steplessly setting the enlargement and reduction magnification, and 308 for displaying the set magnification. Display section, 30g is a density setting section for setting the copy density, 30a, 30b, 30C130d are operation keys for moving a spot light source that indicates the erase position of the original, which will be described later, 30e is a position designation for inputting the coordinate position indicated by the spot light source Keys 30f and 30Q are erasing range designation keys for designating erasing ranges at designated positions, 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, 3) 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. Reference numeral 39 denotes a paper feed motor, which is a motor for driving the pair of registration rollers 19. A fan motor 40 is a motor for driving the cooling fan 29.

FIG. 7 shows a driving 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, respectively, and these carriages 411 and 412 are guided by guide rails 42s and 422 in the direction of arrow a. It is said to be able to move in parallel. Also, 4
The phase pulse motor 33 drives a pulley 43. An endless belt 45 is passed between this pulley 43 and the idle pulley 44, and this belt 4
A first carriage 411 that supports the mirror 5 in the middle of the mirror 5
One end is fixed. On the other hand, the guide portion 46 of the second carriage 422 supporting the mirror 6.7 has a rail 42
Two pulleys 47.47 are rotatably provided with a distance M in the axial direction of the two pulleys 47.47H, and a wire 48 is wound around these pulleys 47.47H. 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. Further, one end of a first carriage 411 is fixed to a midway portion of the wire 48. Therefore, by rotating the pulse motor 33, the belt 45 rotates and the first carriage 41
1 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
Let the paper size specified by (PxSPy) be,
If the copy magnification specified by the magnification setting keys 306 and 307 is K, the copyable range (x, y) is "x-P
x/KJ.

"y-P'//Kl. This copyable range (x, y
), the X direction is indicated by the pointer 5 provided on the back of the document table 2.
1.52, and the y direction is indicated by the scale 5 provided on the upper surface of the first carriage 411.
3 and the distance between the fixed scale 21 and the fixed scale 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 the distance between the pointers 51 and 52 is changed by driving the motor 58 in accordance with the determined copyable range in the X direction. It looks like this.

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 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.

FIG. 9 shows the overall control circuit.

The main processor group 71 detects inputs from the operation panel 30 and input devices 75 such as various switches and sensors, for example, the cassette size detection switches 601 and 602, and operates a high voltage transformer 76 that drives the various chargers, and the snow removal lamp. 28, a blade solenoid 27a of the cleaner 2'7, a heater 23a of the fixing roller pair 23,
The exposure lamp 4 and each of the motors 3) to 40.5
8 etc. to perform the above-mentioned copying operation,
Spot light source 13), light receiving section 132, pulse motor 13
5. Memory 1401 Erase array 150, Array driver 1
601 by controlling the 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 source 13
), 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 3) to 40.58, motor 35.37
．． A toner motor 77 that supplies toner to 40 and developing unit 12 is controlled by a main processor group 71 via a motor driver 78, and motors 3) to 34 and 135
are controlled by the first sub-processor group 72 via seven pulse motor drivers, 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
Commands to drive and stop each motor are sent to 1. 1st. A status signal indicating the drive/stop state of each motor is sent from the second sub-processor group 72, 73 to the main processor group 71. Furthermore, the first sub-processor group 72 includes:
Position sensor 8 that detects each initial position of motors 3) to 34
Location information from 3 has been input.

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.

Further, 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.
4 is connected to a size switch for detecting paper size and other human power, and to the input/output port 95 is connected a copying condition setting switch and other human power. Note that the input/output port 96 is an option.

FIG. 11 shows an example of the structure 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. Motors 3) to 34 and 135 are connected to the input/output boat 104 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, 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, and the pulse motor 123 (the pulse motor 3) to 34.36 is connected to the pulse motor driver 122.
．． 38.39.58.135) windings A, B,
A.

B is 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;
It gradually shortens, eventually becomes evenly spaced, then gradually becomes longer again, and then stops. 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.
3) The light receiving section 132 is integrally and movably provided. As shown in FIGS. 16(a) and 16(b), the spot light m13) and the light receiving unit 132 are arranged so that the optical axis of the spot light source 13) is perpendicular to the document table 2. It is disposed on the surface of the document table 2 so as to be inclined so as to intersect with the optical axis of the spot light source 13). Among these, the spot light source 13) is a light emitting element 13)a such as a light emitting diode or a lamp.

It is composed of a lens 13)b and a lens 13)b that guides the light generated from the light emitting element 13)a toward the document table 2, and the light receiving section 1
Reference numeral 32 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. The lighting signal of the light emitting element 13)a 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.

Note that the light emitted from the spot light source 13) 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 13) 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 13) and the light receiving section 132 are moved in a direction perpendicular to the scanning direction of the first carriage 411. In addition, a spotlight is placed on the first carriage 411 located at the end of the guide shaft 130 on the pulse motor 135 side. 1113), 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 13) is moved, first the spot light source 13) is moved to the position sensor 1.
38 and the initial position is detected.

Next, a method of specifying the erasing range of the document using the spot light source 13) will be explained using FIGS. 17 to 19. When specifying the erasing range of the original, the original IG is set with the copy side facing up on the fixed scale 22 side, 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 13)a 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 13) are moved in the scanning direction (the arrow shown in FIG. 17, the X direction). Also,
When the operation keys 30a and 30c are pressed, the motor 135 is driven, and the spot light source 13) is moved in the direction perpendicular to the scanning direction (
(direction of arrow X shown in FIG. 17). The operator presses the operation key 30 while visually observing the spot light transmitted through the document G.
a to 30d to move the spotlight to point Si on the document G shown in FIG. 18(a), for example, and then press the position designation key 30e. Then, the coordinate position specified in 81 is stored in the main processor group 71 shown in FIG. Similarly, when the position designation key 300 is pressed with the spotlight moved to 82 points on the source 111G, the positions of the 82 points are stored in the main processor 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. Thereafter, when the erasure range designation key 30f is pressed, a rectangular area (indicated by diagonal lines) with the 82nd point S1 as the diagonal point is designated as the erasure range, as shown in FIG. 18(a). 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 30Q, the area other than the square with 83 and 84 points as diagonal points will be set as the erase range. It is specified.

In this way, when the erasure range designation keys 30f and 30a 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 140
A high level signal "1'" is stored in the erase range part, and a low level signal "0" is stored in the other part. That is, this memory 140 is constituted by a RAM whose capacity in each column direction is approximately equal to the movement distance of the spot light source 13) in the X direction divided by the position resolution in the y and X directions, and is processed by the data supplied from the main processor group 71. , Figure 18 (
In case a), as shown in Figure 19(a),
In the case of FIG. 18(b), as shown in FIG. 19(b), a high level signal is stored in the address corresponding to the shaded area, and a low level signal is stored in the other addresses.

The original G whose erasing range has been designated as described above is reversed in the X 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 the erasing array 150 matches, for example, the capacity 1 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, and the active contacts 163a of these switch elements 163 are 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 electric current IIL! through a current-limiting resistor R, respectively. Connected to VCC.

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 41! As the photosensitive drum 10 is operated, one column of data is sequentially read from the memory 140 in the row direction (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. That is, the erase array 150 includes the charger 11 and the exposure section Ph.
For example, one column of data output from the memory 140 is arranged between the erase array 150 and the erase array 150.
Assuming that the angle of the exposed portion ph is Jl and the photosensitive drum 10 is rotating at each speed, the latch signal LTH is supplied to the store register 162 before θ1/ω.
The output timing is υII! It has been done.

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 subsequently exposed to light, an electrostatic latent image is not formed, and the original image cannot be erased. Thereafter, the data in the memory 140 is read out column by column in the same manner, 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 8 to 30d is operated, first, the set position of the original is detected. That is, the first time (
As shown in a), the document table 2 is made larger by an extra portion ya than the horizontal length VQ of the maximum document size A3, and when an A3 document G is set on the fixed scale 21 side, there is a gap ya. It is made to occur. To detect the set position of the original, the spot light source 13) and the light receiving section 132 are moved to this surplus area ya, and depending on the presence or absence of the spot light incident on the light receiving section 132, it is determined whether the original is set at the correct position. I am trying to detect it.

Next, the above document detection operation will be explained using FIG. 2. When any of the operation keys 308 to 30d is operated with a document set on the document table 2, the main processor group 71, in step STI, switches the spot light source 3) and the light receiving section 132 to the state shown in FIG. 1(a). The light emitting element 13)a is moved at high speed to the surplus part ya shown in FIG. 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. In other words, when the document G is set on the fixed scale 21 side as shown in FIG. . Therefore, in this case, control is transferred to step STs, and in step ST3, the buzzer 17
0 is sounded to notify that the document is set in an incorrect position. Thereafter, the control is transferred to step ST2 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, as shown in FIG. 1(b), the original is fixed scale 2
2 side, or when the original is set on the fixed scale 22 side, the spot light is reflected by the original and enters the light receiving section 132.
The light receiving element 132a is turned on. Therefore, the control is transferred from step ST2 to step ST4, and in step ST4, the above-described operation of specifying the erasure range is performed. When the erasure range designation operation is completed, the document is set on the fixed scale 21 side and the copy key 301 is operated, the control is transferred to step STs, and the above-described erasure copy operation is performed.

When this erasure copying operation is completed, the process is completed.

According to the above embodiment, the surplus portion ya is provided on the document table 2 so as to be slightly larger than the maximum original size, and when any of the operation keys 308 to 30d is operated when specifying the erasure range, first, the surplus portion ya is The spot light source 13) and the light receiving section 132 are moved to the position ya to detect the set position of the document. Therefore, it is possible to prevent the erasing range from being specified while the original is set in the wrong position, so it is possible to prevent mistakes in specifying the erasing range and 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 document set position, operation keys 3Qa to 3 are pressed.
Spot light source 13), light receiving unit 132 according to the operation of 0d
Since it is moved at a 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] 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 an image forming apparatus according to the present invention, and FIG. 1 is a plan view of the main part shown for explaining the operation of detecting the setting position of an original, and FIG. 2 shows the detection of the setting position of the original. Figures 3 and 4 shown to explain the operation show the configuration of the image forming apparatus. Figure 3 is an external perspective view, Figure 4 is a side sectional view, and Figure 5 is an operation panel. FIG. 6 is a plan view showing the configuration of the drive unit, 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, and FIG. 8 is a pointer drive f! FIG. 9 is a block diagram showing the overall control circuit, FIG. 10 is a block diagram of the main processor group, FIG. 11 is a block diagram of the first sub-processor group, and FIG. 12 is a perspective view schematically showing the sm. is a configuration diagram of the second sub-processor group,
Figure 3 is a schematic configuration diagram showing the control circuit of the pulse motor.
Figure 4 is a diagram shown to explain the speed control method of the pulse motor, Figure 15 is a perspective view of the main part showing the spot light source, and Figures 16 (a) and (b) are side views of the main part showing the spot light source. 17 and 18 are respectively plan views for explaining the erasing range designation operation of the document using a spot light source, FIG. 19 is a diagram for explaining the contents of the memory, and FIG. 20. 21 and 22 respectively show the relationship between the erasing array and the photosensitive drum; FIG. 21 is a perspective view showing only the essential parts; Figure 22 is a front view showing only the main parts, and Figure 23 shows the configuration of the erasing array.
) is a side sectional view, FIG. 24 is a partially cutaway front view, FIG.
The figure is a side sectional view of the main parts showing another example of the arrangement of the erasing array. DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photosensitive drum, 3o...Operation panel, 30a-30d...Operation keys, 30e...Position specification key, 30f, 30Q...
・Erase range specification key, 71...main processor group,
13)... Spot light source, 132... Light receiving section, 14
0...Memory, 150...Erase array, 160...
-Array drive unit, P...paper, Ph...exposure unit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (b) Figure 12 Figure 13 Figure 915 Figure 16 (a) Figure 16 (b) Figure 17 (a) Figure 20 g25v! J Figure 21 (a) (b) 1 bow 0 Figure 24

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 detection means movable together with the instruction means; and a detection means that moves the detection means near the second document setting reference to detect the document setting position. An image forming apparatus comprising: a control means for controlling the image forming apparatus; (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. .