JPS61258279A - Image forming device - Google Patents

Abstract

PURPOSE:To detect an original size with a high precision by providing a detecting means consisting of light emitting elements and photodetectors to detect sizes in both directions of an original and lighting light emitting elements to designate an erase range when the erase range is designated and leading the reflected light from the original to alight receiving part by a half mirror. CONSTITUTION:When an original G is brought closely into contact with an original platen 2, the reflected light from the original G of a spot light is reflected on a half mirror 133 and is led to a photodetector 132b. Even if the original G is raised above the original platen 2, the reflected light is led there similarly to detect the presence/absence and the size of the original accurately. When the spot light is moved to a point S1 on the original G and a position designating key 30e is depressed in this state, the coordinate position designated by the point S1 is stored in a main processor group. When the spot light is moved to a point S2 on the original G and the position designating key 30e is depressed in this state similarly, the position of the point S2 is stored also. When points S3 and S4 on the original G are designated and an erase range designating key 30g is depressed, the part other than a square having diagonal point S3 and S4 is designated as the erase range.

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]

As is well known, in electronic copying machines, means have been developed for automatically detecting the size of a document set on a document table (transparent glass). This detection means has a plurality of light emitting elements and light receiving elements arranged along the longitudinal direction on the back side of the document table, and when the document cover is closed, the light emitting elements emit light in the direction of the document table. The size of the document is detected by detecting the reflected light from the document set in the scanner and the light reflected from the document cover using light-receiving elements, and by detecting the portion where the level of the output signal of these light-receiving elements changes. be.

By the way, in the case of the above conventional configuration, it is necessary to provide light emitting elements and light receiving elements corresponding to the size of the original on the back side of the original table.

Therefore, many light receiving elements and light emitting elements are required.
It is also necessary to secure space for these.

Generally speaking, the surface of the document cover that faces the document table is white, and when the above detection means is performed with the document cover closed, there is not much difference in the amount of light reflected from the document and the light reflected from the document cover. , it was difficult to reliably detect the document size.

Generally, electronic copying machines have the function of copying the original image onto paper as is, or enlarging or reducing the original image. It could not be erased and copied.

[Object of the invention] This invention was made based on the above circumstances,
The purpose is to be able to detect the size of a document in both directions with high precision with a simple configuration, and to form an image by selectively erasing unnecessary parts of the document.
Furthermore, it is an object of the present invention to provide an image forming apparatus that can accurately detect even when the original is floating.

[Summary of the invention]

In the present invention, for example, the first carriage constituting the scanning means is provided with a first detection means consisting of a pair of light emitting element and light receiving element driven in a direction perpendicular to the moving direction of the carriage, and the first detection means is provided to detect the size of the original. driving the first detection means at the time, detecting the size of the document in both directions based on a change in the output signal of the light receiving element at this time, and lighting up the light emitting element in the first detection means when specifying an erasing range of the document; The erasing range is designated by the spot light that passes through the original, and a half mirror is provided in the middle of the optical path of the light emitting part to transmit the spot light from the light emitting part and guide the reflected light from the original to the light receiving part. This is what I did.

[Embodiments of the invention]

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

15 and 16 schematically show an image forming apparatus, such as a copying machine, according to the present invention. That is, 1 is a main body of a copying machine, and a document table (transparent glass) 2 is fixed to the upper surface of the main body 1 to support a document. The document table 2 is provided with a fixed scale 21 that serves as a reference for setting the document.
Furthermore, a document cover 1 that can be opened and closed is located near the yA document table 2.
+ and a work table 12 are provided. The original placed on the original platen 2 is moved back and forth by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 along the lower surface of the original platen 2 in the direction of arrow a. It is designed to be exposed and scanned.

In this case, mirror 6.7 moves at half the speed of mirror 5 so as to maintain the optical 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 further passes through the mirror 9. reflected by and guided to the photoreceptor drum 1o,
An image of the original is formed on the surface of the photosensitive drum 10.

The photosensitive drum 10 rotates in the direction of arrow C in the figure, and the surface is first charged by the charging device 11, and then the image is exposed to slit light, thereby forming an electrostatic latent image on the surface. This electrostatic latent image is made visible by applying toner by a developing device 12.

On the other hand, the paper (image-forming object) 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, passes through the paper guide path 17 or 18, and then passes through the registration roller. versus 19
and is guided to the 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. Note that 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. This cassette size detection switch 60r
, 602 are composed of III microswitches that are turned on and off in accordance with the insertion of cassettes of different sizes.

The paper P sent to the transfer section comes into close contact with the surface of the photoreceptor drum 10 at the transfer charger 20, so that the toner image on the photoreceptor drum 10 is transferred by the action of the charger 20. . This transferred paper P is transferred to the peeling charger 2
1, the image is electrostatically peeled off from the photoreceptor drum 10, conveyed by the conveyor belt 22, and sent to the fixing roller 523 as a fixing device provided at the end of the conveyor belt 22, where the transferred image is transferred. It will be established. Then, paper P after fixing
is arranged to be placed on a tray 25 outside the main body 1 by a pair of paper ejection rollers 24. After the photosensitive drum 10 has been transferred, the charge is removed by the 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 drum 10 returns to its initial state. It looks like this. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

FIG. 17 shows the operation panel 30 provided on the main body 1. 301 is a copy key for commanding the start of copying; 30
2 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; 304 is a cassette selection key for selecting the upper and lower paper feed cassettes 13 and 14; 30!5 is a selection key 305 is a magnification setting key for setting the enlargement/reduction magnification of copying in a predetermined relationship; 307 is a zoom key for steplessly setting the enlargement/reduction magnification; and 308 is a zoom key for setting the set magnification. 30g is a density setting section for setting the copy density; 30a, 30b, 30c, and 30d are scanning keys for moving a spot light source that indicates the erase position in III, which will be described later; 30e indicates a coordinate position indicated by the spot light source. Position designation keys to be input, 30f, 30 and l are erasure range designation keys to designate the erasure range at each designated position, 30h is a check key that is scanned to check the document size, and 301 is a check key to check the document size. , an automatic magnification key 30j that automatically determines the copy magnification so that the image of the checked original is copied according to the paper size;
30 has a check key 30h and an automatic magnification key 3.
This is a light emitting display element that indicates that 0i has been scanned.

FIG. 18 shows an example of the configuration of a drive source for 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.

A mirror motor 32 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. A drum motor 36 is a motor for driving the photosensitive drum 10. 37 is a fixing motor that connects the paper conveyance path 22 and the fixing roller pair 2.
3 and a pair of paper discharge rollers 24. Reference numeral 38 is a paper feed motor, which is connected to the feed rollers 15 and 16.
This is a motor for driving. A paper feeding motor 39 is a motor for driving the registration roller pair 19. 4o is a fan motor, and the cooling fan 29
This is a motor for driving.

FIG. 19 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 mirrors 6 and 7 are supported by a second carriage 412, respectively, and these carriages 411 and 412 are guided by guide rails 421 and 422 in the direction of arrow a. It can be moved in parallel. That is, the four-phase pulse motor 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, two pulleys 47.47 are rotatably provided in the guide section 46 of the second carriage 412 that supports the mirror 6.7, spaced apart in the axial direction of the rail 422. A wire 48 is strung around. One end of this wire 48 is attached to the fixed part 49,
The other ends are fixed to the fixing portions 49 via coil springs 50, respectively. 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 411 moves,
Accordingly, the second carriage 412 also moves. At this time, since the pulleys 47 and 47 act as movable pulleys,
The second carriage 412 moves in the same direction as the first carriage 411 at 1/2 the speed.

Note that the moving directions of the first and second carriages 411 and 412 are controlled by switching the rotation direction of the pulse motor 33.

Further, the paper size specified by the paper selection key 304 is (PX, PM), and the magnification setting keys 30s,
If the copy magnification specified by 307 is K, then the copyable range (x, y), [x - Px/KJ , ry - P
It becomes y/KJ. Of this copyable range (X, y), the X direction corresponds to the lateral direction of the document table 2, and the y direction corresponds to the longitudinal direction of the document table 2.

FIG. 20 shows the overall control circuit, in which the main processor group 71 and the first . 2nd subprocessor group 72.73
It is mainly composed of. The main processor group 71 includes an operation panel 30 and various switches or sensors such as the cassette size detection switches 60r and 60.
A high-voltage transformer 76 that detects input from an input device 75 such as 2 and drives the various chargers, and 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 controlling each of the motors 31 to 40.58, etc.,
In addition to performing the above-mentioned copying operation, it also controls a spot light source 131 as a first detection means, a light receiving section 132, a pulse motor 135 for driving these, a microswitch 140 as a second detection means, and a memory 851, which will be described later. In addition to detecting the original size, the erasing array 150,
The array drive unit 16o1 memory 852 is used to erase the original image.

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
Main processor from sub-processor group 72.73! l
A status signal indicating the drive/stop state of each motor is sent to ¥71. Further, the first sub-processor group 72 receives position information from a position sensor 83 that detects the initial positions of the motors 31 to 34.

FIG. 21 shows an example of the configuration of the main processor group 71. That is, 91 is a one-chip microcomputer (hereinafter simply referred to as microcomputer), which detects human input of keys on an operation panel (not shown) and controls various displays via an input/output board 92. Also, 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, and a size switch for detecting paper size and its respective inputs are connected to the input/output boat 94.
A copy condition setting switch and its respective inputs are connected to the input/output boat 95. Note that the input/output port 96 is an option.

FIG. 22 shows an example of the configuration of the first sub-processor group 72. That is, 101 is a microcomputer, which is connected to the main processor group 71. 102 is a programmable interval timer for controlling the phase switching interval time of the pulse motor, and when a set value is set from the microcomputer 101, it counts based on it, and when it has counted out, it sends an end pulse to the interrupt line of the microcomputer 101. Output. A reference clock pulse is input to the timer 102. 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 via the pulse motor driver 79. The input/output coupler 1-103 is used, for example, when outputting status signals of each pulse motor to the main processor group 71.

FIG. 23 shows the configuration of the second sub-build O setter group 73. That is, 111 is a microcomputer, which is connected to the main processor group 71.

112 is a programmable interval timer for controlling the phase switching interval time of the pulse motor;
By setting a set value from 1, it counts based on it, and outputs an end pulse when the count is out. 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 motors 36, 38, 39, and 58 are connected to the input/output boat 114 via the pulse motor driver 80.

Figure 24 shows the control circuit of the pulse motor, and shows the input/output boat 121 (input/output boat 1 in Figures 11 and 12).
04.114) has a pulse motor driver 122
A pulse motor driver 123 (corresponding to the pulse motor driver 79.8o in FIG. 9) is connected to this pulse motor driver 122 (corresponding to the pulse motor driver 79.8o in FIG. 9).
．． 39.135) are connected to each other.

Figure 25 shows a method for controlling the speed of a pulse motor.

The figure (a) shows the speed curve of the pulse motor, and the figure (b) shows the phase switching interval. As is clear from this figure,
At first, the phase switching interval is long, gradually shortens, eventually becomes equal, then gradually becomes longer again, and then stops. That is, this indicates the slew-up and slew-down of the pulse motor, starting from the self-starting region, being used in the high-speed region, and finally falling down. In addition, 1. , t2・
...tx indicates the time of the phase switching interval.

Next, the gist of the invention will be explained. 1 to 3, the first carriage 411 includes an exposure lamp 4.
A guide shaft 130 is provided along the part where the light is blocked. On this guide shaft 130, a spot light 1 [! 131,
A light receiving section 132 and a half mirror 133 are provided integrally and movably. These spot light sources 1
31, the light receiving section 132 and the half mirror 133 are provided so that the optical axis of the spot light source 131 is perpendicular to the document table 2, and the optical axis of the light receiving section 132 is perpendicular to the document table 2, as shown in FIG. 3(a). It is placed parallel to the The spot light source 131 includes a light emitting element 131a and this light emitting element 13.
Lens 1 that guides the light generated from 1a 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.

As a result, as shown in FIG. 3(b), when the original is in close contact with the original platen 2, the light from the light emitting element 131a is guided to the original platen 2 via the lens 131b and the half mirror 133. The reflected light from the document G due to the spot light is reflected by the half mirror 133 and guided to the light receiving element 132b via the lens 132b. Further, as shown in FIG. 3C, even when the original G is lifted off the original table 2, the reflected light from the original G is guided to the light receiving element 132b.

As a result, even if the original G is floating, it is possible to accurately detect the presence or absence of the original and its size. Roughly,
The spotlight drawn by the spot light source draws a round green color instead of the edge, and can be used as a trimming position specifying means in the document trimming function.

Further, the lighting signal of the light emitting element 131a 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.

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 spotlight 11171 is directed to the first carriage 411.
is moved in a direction perpendicular to the scanning direction. Further, a first carriage 411 located at the end of the guide shaft 130 on the pulse motor 135 side includes a spot light source 131 and a light receiving section 132.
A position sensor 138 consisting of a microswitch is provided to detect the initial position of.

As a result, when the spotlight i[1[131] is moved, for example, the lower end of the spotlight 1[1131 first comes into contact with the position sensor 138, and the initial position is detected.

On the other hand, as shown in FIG. 4, a rotator 13 is provided at the starting end of the document cover 11, which is located inside the main body 1 and is rotated together with the document cover 11. This rotating element 1
3, there is a second sensor for detecting the open/closed state of the document cover 11.
The microswitch 140 is provided as a detection means.

The arrangement position of this 140 is determined as follows. That is, when the maximum release angle of the document cover 11 is θmax, the microswitch 140 is set so that the rotator 13 comes into contact with the movable element 141 of the microswitch 140 and the switch state is turned on when the release angle θ1 is reached. And the arrangement position of the rotator 13 is defined. Also, θ2 from the maximum release angle θmax to the release angle θ1 is
The original cover 11 in the released state is held released within the range of this play angle θ2 by a holding member made of a spring or the like (not shown).

In the above configuration, the operation will be explained. Usually the first
As shown in FIG. 5, the carriage 411 is parked at the farthest position from the fixed scale 21, that is, at one longitudinal end of the document table 2, and the first detection means is located at the spot light source 13.
1 is positioned at the center of the document table 2 in the lateral direction and is on standby. In this state, the document cover 11 is released, and the document G is set using the center of the fixed scale 21 as a reference.
For example, press the check key 30'h. When the document cover 11 is closed at this moment, the microswitch 140 is turned on with the document cover 11 rotated to the opening angle θ1 shown in FIG. 5, and this ON output is supplied to the main processor group 71. .

In response to this ON output, the main processor group 71 supplies a lighting signal to the light emitting element 130a of the spot light source 131, and also supplies a high speed drive command signal for the first carriage 411 to the sub processor group 72.

Therefore, the light emitting element 131a is turned on, and the first carriage 411 is moved in the direction of the fixed scale 2 at a lower speed than the operating speed during normal copying. Accordingly, the spot light source 131 and the light receiving section 132 are moved from the 01 point toward the D5 point, as shown in FIG. This 01
Most of the light emitted from the spot light source 131 passes through the document table 2 from the point to the point B2 located at the edge of the set document G. In other words, the first carriage 41
Since the speed at which the document cover 11 moves in the direction of the Os point force from the 01 point is set faster than the speed at which the original cover 11 normally rotates between the release angles 01 and 01, the speed at which the document cover 11 moves from the 01 point to the Os point force direction is set faster than the normal rotation speed of the document cover 11 between the release angles 01 and 01. This means that the document cover 11 is open. Therefore, the spot light W131 and the light receiving section 1
Spot light source 1 while 32 moves from point 01 to point B2
Most of the light emitted from 31 passes through document table 2, and light-receiving element 132a of light-receiving section 132 is in an off state. Then, the spot light 8131 and the light receiving section 13
When 2 reaches the 02 point, the light emitted from the spot light source 131 is reflected by the document G and enters the light receiving section 132, so that the light receiving element 132a of the light receiving section 132 is turned on.

Then, the first carriage 411 is roughly moved in the direction of the fixed scale 21 from this point B2, and at the same time, the motor 135 is driven according to the ON output of the light receiving element 132a, and the spot light 11 [131 and the light receiving section 132] are driven. #! As shown in FIG. 5, the document cover 11 is moved in a direction away from the starting end. Then, as shown at point B3, when the spot light source 131 comes out from the edge of the document G, the light receiving element 132a is turned off again, and in this state, the spot light 111131, the light receiving section 132, and the first carriage 411 are further operated. As a result, the end of the first carriage 411 is reached at point B4, and thereafter it is moved to point B5 while remaining at that position.

In this way, the number of driving pulses of the pulse motor 33 that drives the first carriage 411 is controlled by, for example, the main processor group 7 By counting, the size of the original G in the y direction can be detected from this counted value. Also, the document G is placed on the document table 2.
The spot light source 131 is set based on the center of the
are located at the center of the document table 2 from point 01 to point B2. Therefore, if the main processor group 71 counts the number of driving pulses of the pulse motor 135 that drives the spot light + [1131 and the light receiving section 132, for example, from when the light receiving element 132a is turned on until it is turned off again, ! 1
The size of IIG in the X direction is determined by 2XE, where E is the count value.

By the way, in the counting method in the y direction, the spot light source 1
The number of driving pulses PIIi of the first carriage 411 necessary for moving the spot light source 131 and the light receiving part 132 from point 01 to point B5 is stored in advance in the main processor group 71, and this driving pulse is stored in advance in the main processor group 71. Number P1s
By subtracting the number of drive pulses P12 required until the light receiving element 132a turns on from , the number of drive pulses P2S corresponding to the size of @lG in the y direction can be obtained as P2S P2S■Pt s - Pi 2 . With this kind of configuration,
When the spot light [131 and the light receiving unit 132 reach the point B2, the document size in the y direction can be detected, and the detection can be performed quickly.

When the size of the document G in the X and y directions is detected in this way, the detected document size PQX, Pay and the size of the selected paper in the y direction (paper feeding direction) Py, x
The optimum copy magnification Kx is determined from the size Px in the direction (direction perpendicular to the paper feeding direction).

KV is determined in the main processor group 71. That is, this copying magnification Kx,) (y is KX-PX/PQ
It is obtained from the relationship: X Ky-PY/PQ¥. In addition, the paper size Px, P
y is stored in memory 851 in advance.

Next, the copying magnifications KX and Kl that allow the largest number of original images to be copied onto the selected sheet of paper are selected. In other words, for example, if an A4 size original is set with its longitudinal direction along the fixed scale 21, and a B5 size paper with its longitudinal direction set along the paper feeding direction is selected, the y direction of the original is The copying magnification KV determined based on the size results in enlarged copying, and it is difficult to copy the original image within the range of the paper. Therefore, using the copying magnification Kx determined based on the size of the original in the X direction results in reduced duplication, which allows more original images to be copied onto paper than in the above case. That is, the smaller one of the obtained copying magnifications KX and KV is selected as the optimum copying magnification.

In this way, the selected copy magnification is displayed on the display section 3230B of the operation panel 30, for example.

Further, when the automatic magnification change key 30b is operated and the document cover 11 is closed with the document G set,
The optimum copying magnification is determined as described above, and the motors 31, 32, etc. are operated according to this copying magnification, and the lens block 8 or the mirrors 5, 6, etc. are moved.

As mentioned above, when the check key 30h or the automatic magnification change key 30b is operated, the first carriage 411 is moved to the fixed scale 21 side, and the spot light source 131 and the light receiving section 132 are stopped at the position corresponding to the Ds point. . . The stop position of the first carriage 411 coincides with the copy start position.

When the check key 30h is operated and the copy key 301 is operated, the exposure lamp 4 is
is lit and the first carriage is 41! is fixed scale 2K
The copying operation is performed at the same size. Further, when the copy key 301 is operated while the automatic magnification change key 301 is operated, a copying operation is performed using the obtained copy magnification. When these copying operations are completed, the first carriage 411 and the spot light source 131,
The light receiving section 132 is placed on standby at point D1 shown in FIG. Further, when a predetermined period of time has elapsed after operating the check key 30h or the automatic magnification change key 30i, the first carriage 411
, spot light source 131, and light receiving section 132 are D shown in FIG.
It is moved to one point and enters a standby state.

Note that the fixed scale 2 of the first carriage 411! Although it is assumed that the stop position on the side coincides with the copy start position, in reality, a predetermined distance is required from when the first carrier 411 starts operating at the start of close-up until it reaches a constant speed. It is necessary to take this into account.

Further, during normal copying, the ON output of the microswitch 140 is ignored, and in response to the operation of the copying key 301, the first carriage 411 is first moved from point D1 to 05
It is moved at high speed in the direction of the point, and then 01 at normal copying speed.
Moved towards the point. After copying is completed, the copying machine is stopped at point D1, as shown in FIG.

Next, using FIGS. 6 to 8, the spot light source 13
A method of specifying the erasing range of a document using 1 will be explained. This spot light source 131
It is moved by operating 8 to 30d. That is, when the operation key 30b130d is pressed, the motor 33 is driven, and the first carriage 411 and the spot light source 13 are driven.
1 is moved from point D1 shown in FIG. 5 in the scanning direction (arrow y direction shown in FIG. 6). In addition, the operation key 30a130
When C is pressed, the motor 135 is driven and the spot light source 1
31 is moved in a direction perpendicular to the scanning direction (direction of arrow X shown in FIG. 6). The operator moves the spotlight 11131 to the lower surface of the document G, roughly operates the operation keys 30a to 30d while visually observing the spot light transmitted through the document G,
For example, the position designation key 30e is pressed while the spotlight is moved to point S1 on the document G shown in FIG. 7(a). Then, the coordinate position specified in 81 is stored in the main processor group 71 shown in FIG. Similarly, manuscript G
With the spotlight moved to 82 points, press the position specification key 3.
When you press 0e, the position of 82 points is the main processor group 71.
is memorized. The position of this spotlight can be detected, for example, by counting the number of drive pulses of the pulse motor 33,135. After this, erase range specification key 3
When 0f is pressed, Sr appears as shown in FIG. 7(a).

A rectangular area (indicated by diagonal lines) with 82 points as diagonal points is designated as the erasing range. Also, as shown in FIG. 7(b), if you specify points 83 and 84 on the original G and press the erase range designation key 30g, the area other than the square with diagonal points Ss and 84 will be erased. Specified as a range. In this way, when the erasure range designation keys 30f and 30g are pressed, the main processor group 71 performs calculations based on the positions of the two designated points, and the memory 852 receives a high level signal "I n , a low level signal "0" is stored in the other parts. That is, in this memory 852, for example, the capacity in each column direction is approximately equal to the movement distance in the X direction of the spot light source 131 divided by the position resolution in the
It is composed of a RAM whose resolution is almost the same as the force direction position resolution, and based on the data supplied from the main processor group 71, in the case of FIG. 7(a), the resolution shown in FIG. 8(a) is
As shown in FIG. 7(b), the eighth
As shown in Figure (b), high level signals are stored in addresses corresponding to the shaded areas, and low level signals are stored in other addresses.

In this case, the original is set with the copy side facing up,
After the erasing range has been specified, the document is turned over along the fixed scale 21 of the document table 2. Therefore, as shown in FIG. 8, the information stored in the memory 140 is also actually inverted in the column direction.

On the other hand, as shown in FIG. 9, 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. 10 and 11, 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 inside each of these light-shielding cells 151. A light emitting element 152 made of a light emitting diode, for example, as shown in FIGS. 12(a) and 12(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 852 in the column direction. Here, the distance between the light emitting and light elements 152 is P, and the number is N.
The total length of the erase array 150 is Q-NXP.

The erase array 150 is driven by the array driver 160 described above. As shown in FIG. 13, 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 1400, and a store register 1 in which the contents of this shift register 161 are held.
62, 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 this store register 162, the movable contacts 163a of these switch elements 163 are installed, and the fixed contacts 163b are erase array 1 via resistor R, respectively.
It is connected to each cathode of the light emitting element 152 constituting 50. 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, the original cover 11 is closed and the copy key 30 is pressed! When the first carriage 411 and the photosensitive drum 10 are turned on, the first carriage 411 and the photosensitive drum 10 are operated, and one column of data is sequentially read from the memory 852 in the row direction (as shown in FIG. 8). 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 LTH, which is supplied to the shift register 162 in response to this signal. That is, since the erasing array 150 is arranged between the charger 11 and the exposure section ph, one row of data outputted by the memory 852 may be generated when the angle between the erasing array 150 and the exposure section ph is 01, for example. Assuming that the photosensitive drum 10 is rotating at each speed, 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, each switch element 163 is turned on when it is on, and turned off when it 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, an electrostatic latent image is not formed, and the document imager cannot erase the charge. It has been done. Thereafter, data in the memory 852 is read out column by column in the same manner, and images are erased.

According to the embodiment described above, the optical axis of the spot light source 131 is provided perpendicularly to the document table 2, and the optical axis of the light receiving section 132 is provided parallel to the document table 2. Thereby, the spot light from the spot light source 131 is irradiated onto the original via the half mirror 133, and the reflected light from the original is reflected by the half mirror 133 and guided to the light receiving section 132. As a result, even if the original is floating, the presence or absence of the original and the size of the original can be accurately detected.

In addition, a spot light source 131 as a first detection means and a light receiving section 132 are installed in the first carriage 411.
The document size is detected in accordance with changes in the output signal of the light receiving section 132. Therefore, the size of the document in the X and Y directions can be detected simultaneously. Moreover, since the optimal copying magnification is determined from the detected document size in the x and y directions and the selected paper size, it is possible to calculate the optimal copy magnification not only for standard size documents but also for irregular size documents. It is possible to easily copy images without missing them.

Further, the spot light source 131 makes it possible to specify and erase unnecessary portions of the document.

Therefore, it is convenient for editing the copied image.

Furthermore, the first carriage 411 is provided with a spot light source 131, and this spot light source 131 is also used for detecting the size of the original and specifying the erasing range of the original, so space can be used effectively and the size of the device can be reduced. It is possible to hold it down.

Furthermore, since the document size is detected while the document cover changes from the open state to the closed state, the amount of light incident on the light receiving section varies greatly depending on the portion where the document is present and the portion where the document is not present. Therefore, it is possible to improve the accuracy of detecting the document size. Moreover, since the spot light source and the light receiving section are moved in a direction away from the starting end of the document cover as the document cover is closed, it is possible to gain time for opening the document cover.

Furthermore, since the document size is detected according to the closing operation of the document cover, it is possible to quickly detect the document size and, after the detection is completed, to proceed to the copying operation, resulting in good operability. .

Furthermore, since the first carriage is normally on standby at one end of the document table, which is remote from the fixed scale, the document size can be quickly detected in response to scanning of the check key or automatic magnification key.

Furthermore, since there is no need for multiple light-emitting elements and light-receiving elements as in the past, the number of parts can be reduced, and since the first carriage is provided with the light-emitting part and the light-receiving part,
This has the advantage of reducing the space required for parts.

In addition, in the embodiment described above, it is also possible to use a tocoupler or the like as the second detection means.

Furthermore, the arrangement of the erasing array is not limited to between the charger and the exposure section, but as shown in Fig. 14, it can be arranged between the exposure section and the phenomenon machine to erase the formed electrostatic latent image as specified. It is also possible to configure the data to be erased.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to accurately detect the size of a document in both directions with a simple configuration, and it is also possible to selectively erase unnecessary parts of the document to improve the image quality. It is possible to provide an image forming apparatus that can form images and accurately detect even when the original is floating.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view showing only the main parts of an image forming apparatus, FIG. 2 is a side sectional view showing a part of FIG. 1, and FIG. (a) (b) (c)
is a side sectional view showing the configuration of a spot light source and a light receiving section, FIG. 4 is a plan view for explaining the operation of the document cover, FIG. 5 is a plan view for explaining the operation, and FIGS. 6 to 8. 9 is a plan view for explaining the operation of specifying the erasing range of a document using a spot light source, FIG. 9 is a side sectional view of the main part showing the arrangement of the erasing array, and FIG. 10 is the relationship between the erasing array and the photosensitive drum. FIG. 11 is a front view of FIG. 10, FIG. 12 is a side sectional view showing the configuration of the erase array, FIG. 13 is a circuit configuration diagram showing the configuration of the array drive section, and FIG. 14 is a front view of FIG. FIG. 15 is a side sectional view of the main parts showing another arrangement example of the array, FIG. 15 is an external perspective view of the image forming apparatus, FIG. 16 is a side sectional view of FIG. 15, and FIG. 17 is a plan view showing the configuration of the operation panel. Figure, 1st
Figure 8 is a perspective view showing the configuration of the drive unit, Figure 19 is a perspective view schematically showing the drive mechanism of the optical system, Figure 20 is a perspective view showing the overall control circuit, and Figure 21 is the main processor group. 22 is a configuration diagram of the first sub-processor group, FIG. 23 is a configuration diagram of the second sub-processor group, FIG. 24 is a schematic configuration diagram showing the control circuit of the pulse motor, and FIG. 25 is a configuration diagram of the pulse motor control circuit. FIG. 3 is a diagram for explaining a motor speed control method. DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photosensitive drum, 30...Operation panel, 30a-30d...Operation keys, 30e...Position specification key, 30f, 30a...
・Erase range specification key, 71...main processor group,
85! . 852...Memory, 131...Spot light source, 13
1a... Light emitting element, 132... Light receiving section, 132b.
... Light receiving element, 135... Pulse motor, 140...
・Micro switch, 150... Erasing array, 152
...Light emitting element, 160...Array drive unit, P...
Paper, ph...exposed section. Applicant's representative Patent attorney Takehiko Suzue Figure 2d Article 3rIA (a)? (b) 4ryJ Figure 6 Figure 7 (a) Figure 7 Figure 8 (a) South (b) Figure 9 Figure 14 Figure 10 Figure 11 (a) (b) Figure 13 Figure 15 prisoner

Claims (4)

[Claims] (1) The document placed on the document table is optically scanned by a scanning means that moves along the document table, and a reflected light image from the document is formed on a charged image carrier. In an image forming apparatus that forms an electric charge pattern, develops the electric charge pattern, and then transfers and fixes the electric charge pattern to a transfer material to form an image, the scanner is provided in the scanning means and moves in a direction perpendicular to the moving direction of the scanning means. , a first detection means comprising a light emitting section that irradiates light onto the document and a light receiving section that receives reflected light from the document; and an operation of detecting the size of the document or specifying a predetermined range of the document by the first detection means. a selection means for selecting, an erasing means provided near the image carrier and erasing charges on the image carrier, a means for driving the scanning means and the first detection means when detecting the size of the original; The size of the original is detected by the output signal of the original, and the scanning means and the first detection means are driven when a predetermined range of the original is specified, and an image corresponding to the range specified by the light emitting unit is formed during image formation. a control means for operating and erasing the erasing means, a half mirror is provided in the middle of the optical path of the light emitting section, and the spot light from the light emitting section is transmitted;
An image forming apparatus characterized by having a configuration in which reflected light from a document is guided to a light receiving section. (2) The image forming apparatus according to claim 1, wherein the erasing means comprises a plurality of light emitting elements provided near the image carrier along the longitudinal direction of the image carrier. (3) The image forming apparatus according to claim 1, wherein the size detection of the document is performed in response to a closing operation of a document cover. (4) The image forming apparatus according to claim 1, wherein the scanning means moves faster when detecting the size of the original than when scanning the original.