JPS62200344A - Image forming device - Google Patents

Abstract

PURPOSE:To detect surely the size of an original by moving preliminarily an original scanning means to a position which indicates a normal image forming range but moving the scanning means in the opposite direction if the presence of the original is detected when the closing operation of an original cover is detected and detecting the original size thereafter. CONSTITUTION:A carriage 411 as the original scanning means is provided with a pair of a light emitting element 131 and a light receiving element 132 and is held normally in the position indicating a copiable range. If the presence of the original is detected by the element 132 when the closing operation of an original cover 11 is detected by a microswitch 140, the carriage 411 is moved in the direction opposite to that to the scan start position and is moved toward the scan start position after detection of the absence of the original, and the original size is detected by the output change of the element 132. If the absence of the original is detected by the element 132 when the closing operation of the cover 11 is detected, the carriage is moved toward the scan start position to detect the original size. Thus, the original size is detected surely with high precision.

Description

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

(Prior Art) As is well known, means for automatically detecting the size of a document set on a document table (transparent glass) has been developed for electronic copying machines. This detection means has a plurality of light emitting elements and light receiving elements disposed 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. A device that detects the size of the original by detecting the reflected light from the original placed on the table and the reflected light from the original cover with a light-receiving element, and detecting the portion where the level of the output signal of these light-receiving elements changes. It is.

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.

Furthermore, the surface of the document cover facing 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 leading peak of the light reflected from the document and the light reflected from the document cover. , it was difficult to reliably detect the original I% size.

(Problem to be Solved by the Invention) The above-mentioned drawback that it is difficult to reliably detect the document size is eliminated, and the document size can be detected with high precision and reliability with a simple configuration. The purpose of the present invention is to provide an image forming apparatus.

[Structure of the Invention] (Means for Solving the Problems) The image forming apparatus of the present invention includes a first detection means provided in the scanning means for detecting the presence or absence of a document, and a second detection means for detecting the opening/closing operation of the document cover. The detection means and the scanning means are normally moved to a position indicating the image forming range, and when the second detection means detects the closing operation of the document cover, the first detection means detects the presence of the document. If so, the scanning means is moved in the opposite direction to the scanning start position, and when the first detection means detects that there is no document, the scanning means is moved in the direction of the scanning start position, and the scanning means is moved in the direction opposite to the scanning start position. The size of the document is detected by the output signal of the first detection means, and when the closing operation of the document cover is detected and the first detection means detects that there is no document, the scanning means is moved to the scanning start position. The first detecting means detects the size of the document based on the output signal of the first detecting means.

(Function) The present invention provides, for example, on a first carriage constituting a scanning means, a first detection means consisting of a pair of light emitting element and light receiving element driven in a direction orthogonal to the moving direction of the carriage, This M1 carriage is normally kept on standby at a position indicating the image forming range, and when the second detection means detects the closing operation of the document cover, when the first detection means detects that the document is present, The scanning means is moved from the standby position in the direction opposite to the scanning start position, and when the first detection means detects that there is no document, the scanning means is moved in the direction of the scanning start position, and the output of the light receiving element at this time When the document size is detected based on a change in the signal and the closing operation of the document cover is detected, if the first detection means detects that there is no document, the document is moved from the standby position to the scanning start position. The document size is detected based on the change in the output signal of the light receiving element at this time.

(Example) Hereinafter, an example of the present invention will be described 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 11 that can be opened and opened is provided near the document table 2.
and a work table 12 are provided. and,
The original placed on the document table 2 is exposed and scanned by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 reciprocating along the lower surface of the document table 2 in the direction of arrow a. It is now possible to do so.

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 10,
An image of the document is formed on the surface of the photosensitive drum 1o.

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 static 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 601.
602 is turned on depending on the insertion of a cassette of a different size.
It consists of multiple microswitches that are turned off.

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 2o. . This transferred paper P is transferred to the peeling charger 2
1, it is electrostatically peeled off from the photoreceptor drum 10 and conveyed by the conveyor belt 22, and finally Pa8II! , : The transferred image is sent to a fixing row 523 as a fixing device provided therein, and the transferred image is fixed by passing there. After fixing, the paper P is delivered to a tray 25 outside the main body 1 by a pair of paper ejection rollers 24. After the transfer, the photoreceptor drum 10 is neutralized by the snow removal charger 26, residual toner on the surface is removed by the cleaner 27, and the residual image is erased by the static elimination 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 section for displaying 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; 30s is a selected key. A cassette display section for displaying the cassette, 30g 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 308 for displaying the set magnification. Display section, 30g is a density setting section for setting the copy density, 30a, 30b, 30C130d are scanning keys for moving a spot light source indicating the erasing 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 key 30f13C1 is an erasure range specification key 30 for specifying an erasure range at a designated position, respectively;
h is a check key that is scanned when checking the original size, and 301 is an automatic magnification key that checks the original size and automatically determines the copying magnification so that the image of the checked original is copied according to the paper size. , 30j, and 30 are light emitting display elements indicating that the check key 30h1 and automatic magnification change key 30i have been scanned, respectively.

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 Wi (optical path length) between the mirror 5 and the mirror 6.7 for changing the magnification. 33 is a scanning motor;
This is a motor for moving the exposure lamp 4, mirror 5, and mirror 6.7 for document scanning. 34
is a shutter motor, which is used to adjust the charging width of the photoreceptor drum 10 by the charger 11 when changing the magnification.
(not shown). 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. 3
A fixing motor 7 is a motor for driving the paper conveying path 22, the pair of fixing rollers 23, and the pair of paper ejecting rollers 24. 38 is a paper feed motor, which is connected to the feed roller 15.
This is a motor for driving 16. A paper feeding motor 39 is a motor for driving the registration roller pair 19. A fan motor 4o is a motor for driving the cooling fan 29.

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, 7 are supported by a second carriage 412, and these carriages 411, 412 are supported by guide rails 42! , 422, and can freely move in parallel in the direction of arrow a. 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 fixed to a fixing part 49, and the other end is fixed to the fixing part 49 via a coil spring 50. Further, one end of a first carriage 41 is fixed to the middle part of the wire 48.

Therefore, by rotating the pulse motor 33,
The belt 45 rotates and the first carriage 411 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 set as (Px, Py), and the multiplication: $ setting key 306.
If the copy magnification specified by 307 is K, then the copyable range (X, V), rx-Px/Kl, ry-Py
/KJ becomes. Of this copyable range (x, y),
The 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 601 and 602.
a high-voltage transformer 76 that detects input from an input device 75 such as, and drives the various chargers; the static elimination lamp 28;
The blade solenoid 27a of the cleaner 27, the heater 23a1 of the fixing roller pair 23, the exposure lamp 4, and each of the motors 31 to 40.58 are controlled to perform the copying operation described above, as well as to perform the first detection described later. Spot light 1l1131 as a means, light receiving m5132,
The document size is detected by controlling the corrector drive pulse motor 135, the microswitch 140 as a second detection means, and the memory 851, and the erase array 15
0, the array drive section 160 and the memory 852 are used to erase the original image.

Among the above motors 31 to 40.58, motor 35.37
, 40 and the developing device 12, the toner motor 77 is controlled by the main processor group 71 via a motor driver 78, and
are controlled by the first sub-processor group 72 via a pulse motor driver 79;
8 is controlled by a second sub-processor 73 via a pulse motor driver 80. Further, the exposure lamp 4 is controlled by the main processor group 71 via a lamp regulator 81, and the heater 23a is controlled by the main processor group 71 via a heater control wJ section 82. Then, from the main processor group 71 to the first and second sub-processor groups 72
．． Commands to drive and stop each motor are sent to the first .
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. 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 motors 31 to 34 are connected to the input/output capo 4-104 via the pulse motor driver 79. Note that the input/output board 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-processor 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 22 and 23).
04.114) has a pulse motor driver 122
(Equivalent to pulse motor driver 79.80 in Figure 20)
A pulse motor 123 (the pulse motors 31 to 34, 36, 3) is connected to this pulse motor driver 122.
8.39.135) 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, tl, t2・
...tx indicates the time of the phase switching interval.

Next, the gist of the invention will be explained. Figures 3 and 4
In the figure, a guide shaft 130 is provided on the first carriage 411 along a portion where the light of the exposure lamp 4 is blocked. A spot light source 131, a light receiving section 132, and a half mirror 133 are integrally and movably provided on the guide shaft 130 as a first detecting means for detecting the size of the document. These spot light sources 131,
The light receiving section 132 and half mirror 133 are spot lights)
The optical axis of the light receiving section 11131 is provided to be perpendicular to the document table 2, and the optical axis of the light receiving section 132 is provided parallel to the document table 2. The spot light source 131 is a light emitting element 131a.
and a lens 131b that guides the light generated from the light emitting element 131a toward the document table 2.
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.

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 WA131 and the light receiving section 132 are connected to a timing belt (
(toothed belt) 134. 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 171 is moved 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. Thereby, for example, when the spot light source 131 is moved, the lower end of the spot light source 131 first comes into contact with the position sensor 138, and the initial position is detected.

On the other hand, as shown in FIG. 5, 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 microswitch 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, 02 from the maximum release angle θmax to the release angle θ1
is the play angle of the document cover 11, and the document cover 11 in the released state is released and held 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
The carriage 411 is, for example, A4, as shown in FIG.
The document is placed on standby at a position that indicates the copyable size range, and the spot light source 131 is placed on standby at the center of the document table 2 in the lateral direction. In this state, open the document cover 11, set the A4 size document G in a landscape orientation with the center of the fixed scale 21 as a reference, as shown in FIG. 1(a), and press the check key 30h, for example. do. Thereafter, when the document cover 11 is closed, 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. .

The main processor group 71 supplies a lighting signal to the light emitting element 130a of the spot light source 131 in response to this ON output, and the light emitting element 130a is turned on. In this case, 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. As a result, the main processor group 71 determines that the spot light source 131 is located inside the right edge of the document G, and outputs a high-speed drive command signal for the first carriage 411 in the y1 direction.

Then, the first carriage 411 is moved in the direction opposite to the fixed scale 21 at a higher speed than the scanning speed during normal copying. Along with this, the spot light source 131,
As shown in FIG. 1(a), the light receiving section 132 is
Moved in the direction of the point.

When the light receiving section 132 reaches point B, the light receiving element 132a is turned off. As a result, the main processor group 71 determines that it is located at the edge of the document G, and the first
A high-speed drive command signal for the carriage 411 in the y2 direction is output. As a result, the first carriage 411
The point is moved in the direction of the fixed scale 21, and the light receiving section 132
The light receiving element 132 is turned on. As a result, the motor 135 is driven in response to the ON output of the light receiving element 132a, and the spot light source 131 and the light receiving section 132 are moved in the direction away from the starting end of the document cover 11, as shown in FIG. 1(a). be done. And, as shown by point 01,
When the spot light source 131 comes out from the edge of the document G, the light receiving element 132a is turned off again. In this state, the spot light source 131 and the light receiving part 132 are roughly connected to the first carriage 4
11, it moves to point 02, reaches the end of the first carriage 411 at point C2, and thereafter moves to point D while staying at that position.

In this way, from the time when the light receiving element 132a is turned on (point B) until the spot light source 131 and the light receiving section 132 reach point D, the number of driving pulses of the pulse motor 33 that drives the first carriage 411 is changed. For example, if the main processor group 71 counts y, the y of the original G is determined from this counted value.
The size of the direction can be detected.

Furthermore, 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 from when the light receiving element 132a is turned on until it is turned off again, The size of is determined by 2XH, where H is the count value.

In addition, in the above-mentioned standby state, the document cover 11 is opened and the A4 size document G is set vertically with the center of the fixed scale 21 and the scale 53 as the reference, as shown in FIG. 1(b). , for example, by operating the check key 30h. Thereafter, when the document cover 11 is closed, 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. .

The main processor group 71 supplies a lighting signal to the light emitting element 130a of the spot light source 131 in response to this ON output, and the light emitting element 130a is turned on. in this case,
Spot light 2I! Since the light irradiated by the light receiving unit 131 passes through the document table 2 and does not enter the light receiving unit 132, the light receiving element 132a of the light receiving unit 132 is turned off. As a result, the main processor group 71 determines that the spot light source 131 is located outside the right edge of the document G.

A high-speed drive command signal for the first carriage 411 in the y2 direction is output. Then, the first carriage 411 is moved in the direction of the fixed scale 21 at a higher speed than the scanning speed during normal copying. Along with this, spot light source 1
31. The light receiving section 132 is moved from point A toward point D, as shown in FIG. 1(b). From this point A to point E located at the edge of the set document G, a spot light source 131
Most of the light emitted from the document table 2 passes through the document table 2. In other words, since the speed at which the first carriage 411 is moved from point A to point E is set faster than the speed at which the document cover 11 normally rotates between the opening angles 01 and 01, the spot light source 131 and the light receiving section 132 are moved from point A to point E. The document cover 11 remains open until the point is reached. Therefore, spot light IT! 131 and the light receiving section 132 move from point A to point E, most of the light emitted from the spot light source 131 passes through the document table 2, and the light receiving element 132a of the light receiving section 132 is in an off state. . When the spot light source 131 and the light receiving section 132 reach point E, 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. becomes.

Then, the first carriage 411 is further moved in the direction of the fixed scale 21 from this point E, and at the same time, the motor 135 is driven in accordance with the ON output of the light receiving element 132a, and the spot light source 131 and the light receiving section 132 are moved as shown in FIG. As shown in (b), the document cover 11 is moved in a direction away from the starting end. Then, as shown by one point, when the spot light source 131 comes out from the edge of the document G, the light receiving element 132a is turned off again. As the first carriage 411 moves, it reaches the end of the first carriage 411, and is thereafter moved to point D while staying at that position.

In this way, from the time when the light receiving element 132a is turned on until the spot light source 131 and the light receiving section 132 reach the point D, the number of drive pulses of the pulse motor 33 that drives the first carriage 411 is controlled by, for example, the main processor. By counting in the group 71, 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 D1 to point D2. Therefore, from when the light receiving element 132a is turned on until it is turned off again, the number of drive pulses of the pulse motor 135 that drives the spot light i[131 and the light receiving section 132 can be adjusted, for example.

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

Ky is determined in the main processor group 71. That is, this copying magnification Kx,)<y is KX-PX/Pl
; IX Ky-py/pay. In addition, the paper size Px, p
y is stored in memory 851 in advance.

Next, copying magnifications KX and Ky 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 you take an A4 size document, its longitudinal direction is fixed at a scale of 2! If B5 size paper with its longitudinal direction aligned with the paper feeding direction is selected, the copy magnification Ky calculated based on the size of the original in the y direction will result in an enlarged copy, and the original will be enlarged. It is difficult to copy the image within the confines of the paper. Therefore, by using the copying magnification KX determined based on the size of the original in the X direction, reduced copying is performed, and more original images can be copied onto paper than in the above case. That is, the smaller of the obtained copying magnifications KX and toy is selected as the optimum copying magnification. In this way, the selected copy magnification is displayed on the display section 308 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 in accordance with this copying magnification, and the lens block 8, mirror 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 changes to the fixed scale 2! The spot light [131] and the light receiving section 132 are stopped at a position corresponding to the D-da 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 lit from that position and the first carriage 411 is moved to the fixed scale 2.
1, and a copying operation of the same size is performed. Further, when the automatic magnification change key 301 is operated, the copy key 30! When is operated, a copying operation is performed using the obtained copying magnification. When these copying operations are completed, the first carriage 411 and the spot light source 131
, the light receiving unit 132 is placed on standby at point A shown in FIG. 1(a). Also, check key 30h or automatic magnification key 30
After a predetermined period of time has elapsed after operating i, the first carriage 411, spot light source 131, and light receiving section 132 are moved to point A shown in FIG. 2 and placed in a standby state.

It is assumed that the stop position of the first carriage 471 on the fixed scale 21 side coincides with the copying start position, but in reality, the first carriage 411 starts operating at the start of copying until it reaches a constant speed. Since a predetermined distance is required, this must be taken into consideration.

Further, during normal copying, the ON output of the microswitch 140 is ignored, and in response to the operation of the copy key 301, the first carriage 411 is first moved at high speed from point A to point D, and then, It is moved toward point A at normal copying speed. After copying is completed, the machine is stopped at point A, 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 is connected to the operation key 30 described above.
It is moved by operating a to 30d. That is, when the operation keys 30b and 30d are pressed, the motor 33 is driven, and the first carriage 411 and the spot light source 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 keys 30a, 30
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 sets the spot light source 131 to the source 1.
11G, and further operated the operation keys 30a to 30d while visually observing the spot light transmitted through the original 1iG, and moved the spot light to, for example, point S1 on the document G shown in FIG. 7(a). In this state, press the position designation key 30e.

Then, the coordinate position specified by this Sl is stored in the main processor group 71 shown in FIG. Similarly, when the position designation key 308 is pressed with the spotlight moved to 82 points on the original IG, the positions of the 82 points are stored in the main processor group 71. 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, when the erasure range specification key 30f is pressed, the area is 81°8 as shown in FIG. 7(a).
A rectangular area (indicated by diagonal lines) with two diagonal points is designated as the erasing range. Further, as shown in FIG. 7(b), if points 83 and 84 of the original G are specified and the lover range specification key 30a is pressed, 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 specified points, and the memory 852 stores the high level signal n 111 in the erasure range area. 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 constituted by 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 as shown in FIG. 8(a)
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 erase IIB designation is completed, the document is turned over along the double fixed scale 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 FIG. 12(a)l) is provided. Furthermore, a lens 153 is provided in the opening of each cell 151 facing the photoreceptor drum 1o 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, 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. 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 140, 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 which are controlled on and off by each output signal of this store register 162, and the movable contacts 163a of these switch elements 163 are installed,
The fixed contacts 163b are connected via resistors R to each cathode of the light emitting elements 152 constituting the erase array 150, respectively. The anode of each of these light emitting elements 152 is 1! They are connected to the power supply CC through respective flow-limiting resistors R.

After specifying the erasing range of the original as described above, when the original cover 11 is closed and the copy key 301 is turned on, the first carriage 411 and the photosensitive drum 10 are operated, and the data is stored in the row direction from the memory 852. One column of data is sequentially read out (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 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 output from the memory 852 is generated when, for example, the angle between the erasing array 150 and the exposure section ph is θ1. 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, no electrostatic latent image is formed, and the original image is not erased. It means that it was done. Thereafter, data in the memory 852 is read out column by column in the same manner, and images are erased.

According to the above embodiment, the first carriage is provided with a pair of light emitting element and light receiving element as the first detection means, and the first
The carriage is normally kept in standby at a position that indicates the copyable range, and when the closing operation of the document cover is detected by the microswitch serving as the second detection means, if the presence of a document is detected by the light receiving section, the above-mentioned When the scanning means is moved from the standby position in the direction opposite to the scanning start position and the light receiving section detects that there is no document, the scanning means is moved in the direction of the scanning starting position, and the change in the output signal of the light receiving element at this time causes , when the document size is detected and the closing operation of the document cover is detected, and if the light-receiving section detects that there is no document, the document is moved from the standby position to the scanning start position,
The document size is detected based on the change in the output signal of the light receiving section at this time. Therefore, since a plurality of light emitting elements and light receiving elements are not required as in the conventional case, the number of parts can be reduced and the space for arranging the parts can be reduced.

Furthermore, the size of the document can be detected accurately and reliably from the state in which the first carriage indicates the copyable range.

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.
1! 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 maximum image magnification is calculated from the detected document size in the X and y directions and the selected paper size, it is possible to calculate the maximum image magnification not only for regular size documents but also for irregular size documents. Copying can be easily performed without missing the original image.

Also, spot light! 1i131 makes it possible to specify and erase unnecessary portions of a document.

Therefore, it is convenient for arranging copy images, etc.

Furthermore, the first carriage 411 is provided with a spot light source 131, and this spot light fi131 is used to detect the size of the document.
Since it is also used for specifying the erase range of the original, space can be used effectively and the size of the apparatus can be suppressed.

Further, since the document size is detected while the document cover changes from the open state to the open state, the light layer incident on the light receiving section changes 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 the above embodiment, a microswitch is used as the second detection means, but the present invention is not limited to this, and it is also possible to use, for example, a photocoupler that optically detects the operation of the rotator.

Furthermore, the arrangement of the erasing array is not limited to between the charger and the exposure section, but as shown in FIG. It is also possible to configure the data to be erased.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an image forming apparatus that can detect the size of a document with high precision and reliability with a simple configuration.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIGS. 1 and 2 are plan views for explaining the operation, FIG. 3 is a perspective view showing only the main parts of the image forming apparatus, and FIG. FIG. 5 is a side sectional view showing the configuration of the spot light source and the light receiving section, FIG. 5 is a plan view for explaining the operation of the document cover, and FIGS. 6 to 8 each show the operation of specifying the erase range of the document using the spot light source. 9 is a side sectional view of the main parts showing the arrangement of the erasing array, FIG. 10 is a perspective view showing the relationship between the erasing array and the photosensitive drum, and FIG. 11 is a front view of FIG. 10. 12 is a side cross-sectional view showing the configuration of the erase array, FIG. 13 is a circuit configuration diagram showing the structure of the array drive section, and FIG. 14 is a side cross-sectional view of main parts showing another arrangement example of the erase 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 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. The 22nd factor 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 pulse motor control circuit, and FIG. 25 is the pulse motor control circuit. FIG. 2 is a diagram for explaining a speed control method. DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photoconductor drum, 30...Operation panel, 30a-30d...Operation keys, 30e...Position specification key, 30f, 30Q...
・Erase range specification key, 41! ...1st carriage, 5
3...Scale, 71...Main processor group, 8
5i. 852...Memory, 131...Suboc 1-Light source, 1
31a... Light emitting element, 132... Light receiving section, 132b
... Light receiving element, 135 ... Pulse motor, 140.
...Micro switch, 150...Erasing array, 15
2... Light emitting element, 160... Array drive unit, P...
・Paper, pH...Exposure section. Applicant's representative Patent attorney Takehiko Suzue Figure 5 Figure 6 Figure 7 (a) Figure 7 (b) (a) (b) Figure 8 iI9 Figure 914flJ Figure 10 (2) (b) Figure 12 Figure 13

Claims (3)

[Claims] (1) A document table that has a document cover that can be opened and closed, and a scanning means that moves along the document table, optically scans the document placed on the document table, and responds to the reflected light image from the document. an image forming apparatus that forms an image on a transfer material, a first detection means provided in the scanning means for detecting the presence or absence of a document; a second detection means for detecting an opening/closing operation of the document cover; The scanning means is normally moved to a position indicating the image forming range, and when the second detection means detects the closing operation of the document cover, the first detection means detects the presence of the document. In this case, the scanning means is moved in the direction opposite to the scanning start position, and when the first detection means detects that there is no document, the scanning means is moved in the direction of the scanning start position, and the first detection means The size of the document is detected by the output signal of
Further, when the closing operation of the document cover is detected, if the first detection means detects that there is no document, the scanning means is moved in the direction of the scanning start position, and the output signal of the first detection means is used to move the scanning means to the scanning start position. An image forming apparatus comprising: a control means for detecting the size of a document. (2) The first detection means includes a light emitting element that irradiates light onto the document table side and a light receiving element that receives reflected light from the document table side. image forming device. (3) 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.