JPH0685043B2 - Image forming device - Google Patents

Description

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

(Prior Art) As is well known, a means for automatically detecting the size of a document set on a document table (transparent glass) has been developed in an electronic copying machine. The detecting means arranges a plurality of light emitting elements and light receiving elements along the longitudinal direction on the back side of the document table, and illuminates the document table by the light emitting elements with the document cover closed to cause the document table to move. The size of the original is detected by detecting the reflected light from the set original and the reflected light from the original cover with the light receiving elements, and detecting the portion where the output signal level of these light receiving elements has changed. .

By the way, in the case of the above-mentioned conventional configuration, it is necessary to provide light-emitting elements and light-receiving elements for 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 a space for installing these.

Further, the surface of the document cover opposite to the document table is white, and when the above-mentioned 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 amount of light reflected from the document cover. It was difficult to reliably detect the document size.

(Problems to be Solved by the Invention) It eliminates the above-mentioned drawback that it is difficult to reliably detect the size of a document, and it is possible to reliably and accurately detect the size of a document with a simple configuration. An object of the present invention is to provide an image forming apparatus that can be used.

[Structure of the Invention] (Means for Solving Problems) An image forming apparatus of the present invention is a document table on which a document is placed, and an image of the document placed on the document table is exposed at a predetermined exposure scanning start position. An exposure scanning unit that scans while exposing from the same, and stands by at a standby position different from the exposure scanning start position during non-exposure scanning; an image forming unit that forms an image of the original document that is exposed and scanned by the exposure scanning unit; First detecting means which is provided on the original table so as to be openable and closable, and which is provided on the cover means for covering the original table and the exposure scanning means and detects the presence or absence of an original placed on the original table. A second detecting means for detecting an opening / closing operation of the cover means with respect to the original table; a closing operation of the cover means is detected by the second detecting means; and the first detecting means detects the presence of an original. The exposure scanning means is controlled so as to move in a direction opposite to the exposure scanning start position, the closing operation of the cover means is detected by the second detection means, and the first movement is performed. Control means for controlling the exposure scanning means to move in the direction of the exposure scanning start position when the detection means detects the absence of a document;
Also, the size of the document placed on the document table is determined by referring to the detection result of the first detection unit when the control unit controls the exposure scanning unit. It is composed of a judgment means.

(Operation) According to the present invention, for example, the first carriage, which constitutes the scanning means, is provided with the first detection means composed of a pair of a light emitting element and a light receiving element driven in a direction orthogonal to the moving direction of the carriage, When the first detection unit detects the presence of a document when the second detection unit detects the closing operation of the document cover, the first carriage is normally placed on standby at a position indicating the image forming range. When the absence of the original is detected by the first detection means, the scanning means is moved in the direction opposite to the scanning start position from the standby position, and the scanning means is moved in the direction of the scanning start position. When the document size is detected by the change in the output signal, and when the document detection operation is performed by the first detection means when the document cover closing operation is detected, the direction from the standby position to the scanning start position is detected. The document size is detected by the change of the output signal of the light receiving element at this time.

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

15 and 16 schematically show the image forming apparatus of the present invention, for example, a copying machine. That is, reference numeral 1 is a main body of a copying machine, and an original table (transparent glass) 2 for supporting an original is fixed to the upper surface of the main body 1. This is the document platen 2 fixed scale 2 ₁ is provided as a set reference document, further, in the vicinity of the document table 2 document cover 1 ₁ and the work table 1 ₂ opened and closed is provided. Then, the original placed on the original table 2 includes the exposure lamp 4, the mirror 5,
An optical system consisting of 6 and 7 is shown by an arrow a along the lower surface of the document table 2.
By reciprocating in the direction, exposure scanning is performed during the reciprocation. In this case, the mirrors 6 and 7 move at half the speed of the mirror 5 so as to maintain the light dew length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the irradiation of light from the exposure lamp 4 is reflected by the mirrors 5, 6 and 7 and then passes through the lens block 8 for zooming, and further the mirror 9 is passed. It is reflected by and is guided to the photoconductor drum 10, and the image of the document is formed on the surface of the photoconductor drum 10.

The photosensitive drum 10 rotates in the direction of the arrow c in the figure, and the surface is first charged by the charging charger 11 and then the image is slit-exposed to form an electrostatic latent image on the surface. This electrostatic latent image is made visible by the toner attached by the developing device 12.

On the other hand, the paper (image-forming material) P is sent from the selected upper paper feed cassette 13 or lower paper feed cassette 14 to the delivery roller.
Sheets are taken out one by one by 15 or 16, and the paper guide path 17
Alternatively, it is guided to the registration roller pair 19 through 18 and is guided to the transfer portion by the registration roller pair 19. Here, the paper feed cassettes 13 and 14 are detachably provided at the lower right end of the main body 1, and either one of them can be selected on an operation panel described later. The cassette size of each of the paper feed cassettes 13 and 14 is detected by the cassette size detection switches 60 ₁ and 60 ₂ , respectively. The cassette size detection switches 60 ₁ and 60 ₂ are composed of a plurality of micro switches that are turned on / off according to the insertion of cassettes of different sizes.

The sheet P sent to the transfer section is in close contact with the surface of the photoconductor drum 10 at the transfer charger 20, so that the toner image on the photoconductor drum 10 is transferred by the action of the charger 20. . The transferred sheet P is electrostatically peeled off from the photosensitive drum 10 by the action of the peeling charger 21 and is conveyed by the conveying belt 22 to the fixing roller 23 as a fixing device provided at the end portion thereof. The transferred image is sent, and the transferred image is fixed by passing therethrough. Then, the paper P after fixing is paired with a paper discharge roller.
It is designed to be placed on the tray 25 outside the main body 1 by 24. In addition, the photoconductor drum 10 after the transfer is charged by a charger 26 for static elimination.
After the static electricity is removed by the cleaner 27, the residual toner on the surface is removed by the cleaner 27, and the residual image is erased by the static elimination lamp 28, whereby the initial state is restored. Reference numeral 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. 30 ₁ copy key for commanding copy start, 30 numeric keys ₂ for performing setting of the number of copies, 30 ₃ display unit for displaying the jamming of each part of the operating state or paper, is 30 ₄ upper, lower sheet feeding cassette 13 , 14 is a cassette selection key, 30 ₅ is a cassette display section for displaying the selected cassette, 30 ₆ is a magnification setting key for setting the enlargement / reduction ratio of copying in a predetermined relationship, and 30 ₇ is an enlargement / reduction ratio. Is a stepless zoom key, 30 ₈ is a display unit that displays the set magnification, 30 ₉ is a density setting unit that sets the copy density, and 30a, 30b, 30c, and 30d are the erasing positions of the originals, which will be described later. Scan key for moving the spot light source, 30e is a position designation key for inputting the coordinate position indicated by the spot light source, 30f, 30g are erase range designation keys for designating the erase range at each designated position, 30h
Is a chuck key that is scanned when checking the document size, 30i is an automatic scaling key that checks the document size and automatically determines the copy magnification so that the image of the checked document is copied according to the paper size. Reference numerals 30j and 30k denote light emitting display elements that indicate that the check key 30h and the automatic scaling key 30i are scanned.

FIG. 18 shows a drive source configuration example of each drive unit of the copying machine configured as described above, and is configured by the following motors. That is, reference numeral 31 denotes a lens motor, which is a motor for moving the position of the lens block 8 for varying the magnification. Reference numeral 32 denotes a mirror motor, which is a motor for changing the distance (optical path length) between the mirror 5 and the mirrors 6, 7 for changing the magnification. Reference numeral 33 denotes a scanning motor, which includes the exposure lamp 4, the mirror 5, and the mirror.
A motor for moving 6, 7 for scanning the document. Reference numeral 34 is a shutter motor for the photosensitive drum 10 at the time of zooming.
Is a motor for moving a shutter (not shown) for adjusting the charging width of the charging device 11 by the charging device 11. A developing motor 35 is a motor for driving the developing roller and the like of the developing device 12. Reference numeral 36 denotes a drum motor, which is a motor for driving the photosensitive drum 10. A fixing motor 37 is a motor for driving the paper transport path 22, the fixing roller pair 23, and the paper discharge roller pair 24. 38 is a paper feed motor, which is a motor for driving the delivery rollers 15 and 16. A paper feed motor 39 is a motor for driving the registration roller pair 19. Reference numeral 40 denotes a fan motor, which 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 on the first carriage 41 ₁ , and the mirrors 6 and 7 are on the second carriage.
41 ₂ are respectively supported by these carriages 41 ₁ ,
The guide 41 ₂ is guided by guide rails 42 ₁ and 42 ₂ and is movable in parallel in the direction of arrow a. That is, 4-phase pulse motor
33 drives the pulley 43. An endless belt 45 is stretched between the pulley 43 and the idle pulley 44, and the first carriage 41 that supports the mirror 5 in the middle of the belt 45.
_One end of ₁ is fixed. On the other hand, in the guide portion 46 of the second carriage 41 ₂ which supports the mirrors 6 and 7, two pulleys 47 and 47 are rotatably provided apart from each other in the axial direction of the rail 42 ₂ . A wire 48 is hung between 47. One end of the wire 48 is fixed to the fixed portion 49, and the other end is fixed to the fixed portion 49 via a coil spring 50. In addition, the first carriage is provided in the middle of the wire 48.
_One end of 41 ₁ is fixed. Therefore, when the pulse motor 33 rotates, the belt 45 rotates and the first carriage 41 ₁ moves, and the second carriage 41 ₂ also moves accordingly. At this time, since the pulleys 47, 47 function as a moving pulley, the second carriage 41 ₂ moves in the same direction at a speed of 1/2 with respect to the first carriage 41 ₁ . In addition,
The movement directions of the first and second carriages 41 ₁ and 41 ₂ are controlled by switching the rotation direction of the pulse motor 33.

If the paper size specified by the paper selection key 30 ₄ is (Px, Py) and the copy magnification specified by the magnification setting keys 30 ₆ and 30 ₇ is K, the copyable range (x,
y), “x = Px / K”, and “y = Py / K”. Of the copyable range (x, y), the x direction is the lateral direction of the document table 2,
The y direction corresponds to the longitudinal direction of the document table 2.

FIG. 20 shows an overall control circuit, which is mainly composed of a main processor group 71 and first and second sub-processor groups 72, 73. The main processor group 71 is an operation panel
30 and various switches or sensors, for example, a high-voltage transformer 76 that detects an input from an input device 75 such as the cassette size detection switches 60 ₁ and 60 ₂ and drives the various chargers, the static elimination lamp 28, and the blade of the cleaner 27. The solenoid 27a, the heater 23a of the fixing roller pair 23, the exposure lamp 4, the motors 31 to 40, 58, etc. are controlled to perform the above-described copying operation, and also to be described later.
Spot light source 131 as the detection means, the light receiving portion 132, a pulse motor 135 for driving the micro switch 140 as a second detecting means, and performs the detection of the document size by controlling the memory 85 _1, erasing array 150 it is intended to erase the original image using the array driver 160, the memory 85 _2.

Of the motors 31-40, 58, the toner motor 77 for supplying toner to the motors 35, 37, 40 and the developing device 12 is controlled by the main processor group 71 via the motor driver 78,
The motors 31 to 34 and 135 are controlled by the first sub-processor group 72 via the pulse motor driver 79, and the motors 36, 3 are controlled.
9, 38 and 58 are controlled by the second sub processor group 73 via the pulse motor driver 80. 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 unit 82. Then, a drive / stop command for each motor is sent from the main processor group 71 to the first and second sub-processor groups 72, 73, and the first and second sub-processor groups are sent.
Driving each motor from 72, 73 to main processor group 71,
A status signal indicating the stopped state is sent. Also, the first
Position information from a position sensor 83 that detects each initial position of the motors 31 to 34 is input to the sub processor group 72.

FIG. 21 shows a configuration example of the main processor group 71. That is, 91 is a one-chip microcomputer (hereinafter simply referred to as a microcomputer), and has an input / output port.
Through 92, key input detection of an operation panel (not shown) and various display controls are performed. Further, the microcomputer 91 is expanded by input / output ports 93 to 96. A high-voltage transformer 76, a motor driver 78, a lamp regulator 81 and other outputs are connected to the input / output port 93, and a size switch for detecting the paper size and other inputs are connected to the input / output port 94. A copy condition setting switch and other inputs are connected to 95.
The input / output port 96 is an option.

FIG. 22 shows a configuration example 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, which counts based on the set value set by the microcomputer 101, and when the count out occurs, the end pulse is sent to the interrupt line of the microcomputer 101. Output. A reference clock pulse is input to the timer 102. Further, the microcomputer 101 includes the position sensor 83
Location information from is input and input / output port 10
3, 104 are connected. Then, the input / output port 10
4 to the motors 31 to 3 via the pulse motor driver 79.
4 is connected. The input / output port 103 outputs status signals of each pulse motor to the main processor group 71.
It is used when outputting to.

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. Reference numeral 112 denotes a programmable interval timer for controlling the phase switching interval time of the pulse motor, which counts on the basis of a set value set by the microcomputer 111 and outputs an end pulse when it counts out. This end pulse is latched by the latch circuit 113, and its output is supplied to the interrupt line and the input / output port input line of the microcomputer 111. An input / output port 114 is connected to the microcomputer 111, and the motors 36, 38, 39 and 58 are connected to the input / output port 114 via the pulse motor driver 80.

FIG. 24 shows a control circuit of the pulse motor. The input / output port 121 (corresponding to the input / output ports 104 and 114 in FIGS. 22 and 23) has a pulse motor driver 122 (the pulse motor driver in FIG. 20). 79, 80) is connected, and the pulse motor 123 (the pulse motor
31 to 34, 36, 38, 39, 135) of each winding A, B,
, Are connected.

Figure 25 shows the speed control method of the pulse motor.
(a) is a speed curve of the pulse motor, and (b) is a phase switching interval. As is clear from this figure, the phase switching interval is long at first, gradually shortened, then becomes equal intervals, then gradually becomes longer again, and stops. That is, this indicates slew up and slew down of the pulse motor, which means that the pulse motor first rises from the self-starting region, is used in the high speed region, and then falls. Note that t ₁ , t _2, ..., Tx represent the time of the phase switching interval.

Next, the gist of the present invention will be described. 3 and 4
In the figure, the first carriage 41 ₁ is provided with a guide shaft 130 along the portion where the light of the exposure lamp 4 is blocked. On the guide shaft 130, a spot light source 131 as a first detecting means for detecting the size of the document, a light receiving portion 132, and a half mirror 133 are integrally and movably provided. The spot light source 131, the light receiving section 132, and the half mirror 133 are provided so that the optical axis of the spot light source 131 is orthogonal to the original table 2, and the optical axis of the light receiving section 132 is the original table 2.
It is provided in parallel with. Above spot light source 131
Is composed of a light emitting element 131a and a lens 131b that guides the light generated by the light emitting element 131a toward the original table 2. The light receiving section 132 is a light receiving element 132a, and the original table 2 is attached to the light receiving element 132a.
It is composed of a lens 132b that guides the reflected light from.

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.

In addition, the spot light source 131 and the light receiving unit 132 are guide grooves.
It is connected to a timing belt (toothed belt) 134 arranged along 130. The timing belt 134 is wound around a pulley 136 and a driven pulley 137 provided on the rotation shaft of the pulse motor 135. Therefore, when the pulse motor 135 is rotated, the spot light source 171 is moved in the direction orthogonal to the scanning direction of the first carriage 41 ₁ . Further, the first carriage 41 ₁ located to the pulse motor 135 side end portion of the guide shaft 130 spot light source 131, the light receiving portion
A position sensor 138 including a micro switch for detecting the initial position of 132 is provided. Thus, 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 to detect the initial position.

On the other hand, as shown in FIG. 5, the located inside the main body 1 in the start end of the document cover 1 _1, turning member 1 ₃ is provided to be rotated together with the document cover 1 _1. The turning member 1 ₃ wherein the micro-switch 140 as a second detecting means for detecting the open or closed state of the document cover 1 ₁ is in the vicinity of is provided.
The arrangement position of the micro switch 140 is determined as follows. In other words, the maximum release angle of the document cover ₁ 1 θ
If the max, the state became freed angle theta ₁ turning member 1
₃ arrangement position of the micro switch 140 and turning member 1 ₃ such that the switch status is turned on in contact with the armature 141 of the microswitch 140 is defined. Further, theta ₂ of the maximum release angle θmax to release angle theta ₁ is a play angle of the document cover 1 _1, a document cover 1 ₁ in a released state, a spring or the like (not shown) within the scope of this play angle theta ₂ The holding member is configured to be released and held.

The operation of the above configuration will be described. Usually first
As shown in FIG. 2, the carriage 41 ₁ is on standby at a position showing a copyable range of, for example, A4 size, and the spot light source is used.
131 is in standby in the center of the platen 2 in the lateral direction. In this state, the original cover ₁₁ is released and the first
As shown in FIG. (A), sets the original G in a horizontally long state of the A4-size central portion of the fixed scale 2 ₁ as a reference, for example, operates the check key 30h. After this, the document cover 1 ₁
When the document is closed, the document cover ₁₁ opens at the release angle θ shown in FIG.
_The micro switch 140 is turned on in the state of being rotated up to ₁ , and this on output is supplied to the main processor group 71.

A lighting signal is supplied from the main processor group 71 to the light emitting element 130a of the spot light source 131 in response to the 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 is received by the light receiving unit 132.
Therefore, the light receiving element 132a of the light receiving unit 132 is turned on. As a result, the main processor group 71 determines that the spot light source 131 is located inside the right end portion of the document G, and outputs a high speed drive command signal for the first carriage 41 _{1 in} the y ₁ direction. Then, the first carriage 41 ₁ is moved in the direction opposite to the fixed scale 2 ₁ at a speed higher than the scanning speed during normal copying. Along with this, the spot light source 131 and the light receiving section 132 are moved from the point A toward the point B, as shown in FIG.

When the light receiving section 132 reaches the point B, the light receiving element 1
32a is turned off. As a result, the main processor group 71 determines that it is located at the edge of the document G, and outputs a high speed drive command signal for the first carriage 41 _{1 in} the y ₂ direction. Thus, the first carriage 41 ₁ is moved to the fixed scale 2 ₁ direction from the point B, the light receiving element 132 of the light receiving portion 132 is turned on. As a result, the motor 135 in response to the ON output of the light receiving element 132a is driven, so that the spot light source 131 and the light receiving unit 132 shown in FIG. 1 (a), in a direction away from the start end of the document cover 1 ₁ Be moved. Then, as indicated by a point C ₁ , the light receiving element 132a is turned off again when the spot light source 131 is projected from the edge of the document G. In this state, the spot light source 131 and the light receiving section 132 are further moved to the first carriage 41 ₁
Navigate to C ₂ points with the operation, first reaches the end of the carriage 41 ₁ In this C ₂ points, thereafter being moved to the left point D at that position.

In this way, the pulse motor 33 that drives the first carriage 41 ₁ is driven from the time when the light receiving element 132a is turned on (point B) until the spot light source 131 and the light receiving portion 132 reach point D. For example, the main processor group 71
By counting with, the size of the document G in the y direction can be detected from this count value.

Further, the number of drive pulses of the pulse motor 135 for driving the spot light source 131 and the light receiving unit 132 is set to, for example, the main processor group 7 until the light receiving element 132a is turned on and then turned off again.
If counted in 1, the size of the original G in the x direction is H.
Then, it is calculated by 2 × H.

Further, in the standby state, opening the document cover 1 _1,
As shown in Fig. 1 (b), and sets the original G in a vertically long state of A4 size as a reference the central portion and the scale 53 of the fixed scale 2 _1, for example, operates the check key 30h. Thereafter, the document cover 1 ₁ When closing operation, the document cover 1 ₁ is microswitch 140 is turned on in a state of being rotated to release angle theta ₁ shown in FIG. 5, the output turns to the main processor group 71 Supplied. From the main processor group 71, the light receiving element 1 of the spot light source 131 is responsive to the ON output.
30a is turned on. In this case, since the light emitted from the spot light source 131 passes through the document table 2 and is not incident on the light receiving section 132, the light receiving element 132a of the light receiving section 132 is turned off. As a result, the main processor group 71 determines that the spot light source 131 is located outside the right end portion of the document G, and outputs a high speed drive command signal for the first carriage 41 _{1 in} the y ₂ direction. Then, ₁ is a first carriage 41 in the direction of the fixed scale 2 ₁ is moved at high speed than scanning speed during normal copying. With this, spot light source 13
1. The light receiving section 132 is moved from the point A toward the point D as shown in FIG. From the point A to the point E located at the edge of the set document G, most of the light emitted from the spot light source 131 passes through the document table 2. That is, since the first carriage 41 ₁ is set faster than that normally turning speed to be moved document cover 1 ₁ is between release angle theta ₁ to the point E from the point A, a spot light source 131 and the light receiving portion The original cover ₁₁ is open until 132 reaches point E. Therefore, the spot light source 131 and the light receiving unit 1
While 32 moves from point A to point E, most of the light emitted from the spot light source 131 passes through the document table 2,
The light receiving element 132a of the light receiving unit 132 is in the 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 in the on state. Becomes

The first carriage 41 ₁ is moved further fixed scale 2 ₁ direction from the point E, which together with the motor 135 is driven according to the ON output of the light receiving element 132a, the spot light source 131 and the light receiving portion 132 is first as shown in Figure 1 (b), it is moved in a direction away from the start end of the document cover 1 _1. Then, as indicated by a point F, the light receiving element 132a is turned off again when the spot light source 131 is projected from the edge of the document G, and in this state, the spot light source 131 and the light receiving section 132 are further provided.
And the first carriage 41 ₁ and the first carriage 4
After reaching the end of 1 ₁ , it is moved to point D after 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 unit 132 reach point D, the number of drive pulses of the pulse motor 33 that drives the first carriage 41 ₁ is set to, for example, the main pulse. By counting with the processor group 71, the size of the document G in the y direction can be detected from this count value. Further, the document G is set with reference to the center of the document table 2, and the spot light source 131 is located in the center of the document table 2 from point D _{1 to} point D ₂ . Therefore, the pulse motor 135 that drives the spot light source 131 and the light receiving unit 132 until the light receiving element 132a is turned on and then turned off again.
If the number of drive pulses is counted by, for example, the main processor group 71, the size of the document G in the x direction is calculated by 2 × H, where H is the count value.

When the sizes of the original G in the x and y directions are detected in this manner, the detected original sizes Pgx, Pgy and the sizes Py and x in the y direction (paper feeding direction) of the selected paper (feeding direction) are detected. Optimal copy magnification from size Px in the direction orthogonal to the paper direction)
Kx and Ky are calculated in the main processor group 71. That is, the copy magnifications Kx and Ky are obtained from the relationship Kx = Px / Pgx Ky = Py / Pgy. The paper sizes Px and Py are stored in the memory 85 ₁ in advance.

Next, the copy magnifications Kx and Ky that can copy the largest number of original images on the selected paper are selected. In other words, for example, an A4 size original is fixed in the longitudinal direction by a fixed scale 2 ₁
If you select B5 size paper with its longitudinal direction set along the paper feed direction, the copy magnification Ky obtained based on the size of the original in the y direction is the enlarged copy. It is difficult to copy the image within the range of the paper. Therefore, if the copy magnification Kx obtained with reference to the size in the X direction of the original is used, reduction copying is performed, and more original images can be copied onto the paper than in the above case.
That is, the optimum copy magnification is the calculated copy magnification Kx, K
The smaller of y is selected. In this way, the selected copy magnification is displayed on the display unit 30 of the operation panel 30, for example.
Displayed in ₈ .

Also, with the original G set, the automatic scaling key
30b is operated, the document cover 1 ₁ is closing operation, optimum copy magnification is determined as described above, the motor 31 and 32 is operated in accordance with the copy magnification, the lens block 8 or mirror 5, 6 mag will be moved.

As mentioned above, check key 30h or automatic scaling key 3
When 0b is operated, the first carriage 41 ₁ moves to the fixed scale 2 ₁
It is moved to the side, and the spot light source 131 and the light receiving unit 132 are stopped at the position corresponding to point D. This first carriage 41 ₁
The stop position of is coincident with the copy start position. When the check key 30h is operated and the copy key 30 ₁ is operated, the exposure lamp 4 is turned on from that position and the first carriage 41 ₁ is moved in the direction away from the fixed scale 2 ₁ , and the same magnification is applied. The copying operation is performed. In a state where the automatic magnification key 30i is operated, the copy key 30 ₁ is operated, the copying operation by the copying magnification obtained is performed. When these copying operations are completed, the first carriage 41 ₁
The spot light source 131 and the light receiving section 132 are on standby at point A shown in FIG. Further, when a predetermined time has elapsed after operating the check key 30h or the automatic scaling key 30i, the first carriage 41 ₁ , the spot light source 131, and the light receiving section 132 are set to the second
It is moved to the point A shown in the figure and enters the standby state.

The stop position of the first carriage 41 _{1 on} the fixed scale 2 ₁ side is assumed to coincide with the copy start position. However, in actuality, at a constant speed after the first carriage 41 ₁ starts operating at the start of copying. It takes a certain distance before it becomes necessary, so it is necessary to take this into consideration.

Also, during normal copying, the micro switch
On the output of 140 is ignored moved, depending on the copying key 30 ₁ of the operation, first, the first carriage 41 ₁ is fast moving from point A to point D direction, thereafter, the point A direction in normal copying speeds To be done. After copying, as shown in FIG.
Stopped at a point.

Next, referring to FIG. 6 to FIG.
A method of designating an erasing range of a document using will be described. This spot light source 131 has the operation keys 30a to 30d described above.
It is moved by operating. That is, when the operation keys 30b and 30d are pressed, the motor 33 is driven, and the first carriage 41 ₁ and the spot light source 131 move in the scanning direction (direction of arrow y shown in FIG. 6) from point D ₁ shown in FIG. To be done. When the operation keys 30a and 30c are pressed, the motor 135 is driven,
The spot light source 131 is moved in a direction (arrow x direction shown in FIG. 6) orthogonal to the scanning direction. Operator is a spot light source
131 is moved to the lower surface of the original G, and the operation keys 30a to 30d are further operated while observing the spot light transmitted through the original G. For example, spot S ₁ on the original G shown in FIG. 7A is spotted. With the light moved, press the position specification key 30e. Then, the coordinate position designated by S ₁ is stored in the main processor group 71 shown in FIG. Similarly, when the position designation key 30e is pressed in a state where the spot light is moved to the point S _{2 of} the document G, the position of the point S ₂ is stored in the main processor group 71.
The position of this spot light is, for example, the pulse motors 33, 135.
It can be detected by counting the number of drive pulses of. Then, press the erase range specification key 30f
As shown in (a), a rectangular area (hatched) having diagonal points S ₁ and S ₂ is designated as the erasing range. Further, as shown in FIG. 7 (b), the S ₃ point and the S ₄ point of the original G are designated,
Pressing the Clear range designation key 30g, a portion other than the square and S _3, the S ₄ translocation diagonal points is designated as the deletion range. In this manner, when the erase range designation keys 30f and 30g are pressed, the main processor group 71 performs an operation based on the positions of the two designated points, and the memory 85 ₂ has a high level signal "1" in the erase range portion. ", Low-level signal" 0 "is stored in the other parts. That is, the memory 85 _2, for example the capacity of the column is substantially coincident with the position resolution of the moving distance ÷ x direction of the x direction of the spot light source 131, the moving distance ÷ y in the y direction of the capacity of each row direction spotlight 131 It is composed of a RAM whose position resolution is almost the same as that of the directional data.
In the case of, as shown in FIG.
In the case of (b), as shown in FIG. 8 (b), the high level signal is stored at the address corresponding to the shaded portion, and the low level signal is stored at the other addresses.

In this case, the original is set with the copy side as the front,
After erasing range specified end are those flipped along the fixed scale 2 ₁ of the document table 2. Therefore, as shown in FIG. 8, the information stored in the memory 140 is actually inverted and stored in the column direction.

On the other hand, as shown in FIG. 9, an erasing array 150 as erasing means is provided in proximity 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 is provided with a plurality of light shielding cells 151 arranged in a direction orthogonal to the rotation direction of the photosensitive drum 10, and inside each of these light shielding cells 151. Figure 12 (a)
A light emitting element 152 such as a light emitting diode as shown in (b) is provided. Further, 153 for condensing the light of the light emitting element 152 on the surface of the photoconductor drum 10 is provided in the opening of each cell 151 facing the photoconductor drum 10. The number of light emitting elements provided in the erase array 150 is equal to the capacity of the memory 85 _{2 in} the column direction, for example. Here, if the distance between the light emitting elements 152 is P and the number is N, the total length of the erase array 150 is Q = N × P.

The erase array 150 is driven by the array driver 160 described above. As shown in FIG. 13, the array driver 160 includes a shift register 161, which has the same number of bits as the number of bits in the column direction of the memory 140, a store register 162 in which the contents of the shift register 161 are held, and this store register. The switch circuit 164 is composed of a plurality of switch elements 163 which are on / off controlled by the respective output signals of the switch elements 162.
a is installed, and the fixed contact 163b is connected to each cathode of the light emitting element 152 constituting the erasing array 150 via the resistor R. The anode of each of the light emitting elements 152 is connected to the power source Vcc through the resistance R for limiting the current.

Then, when the original cover ₁₁ is closed and the copy key 30 ₁ is turned on after the original erase range is specified as described above,
The first carriage 41 ₁ and the photosensitive drum 10 are operated, and the memory 85 ₂ moves in the row direction (shown in FIG. 8).
The data for one column is sequentially read. The read data D ₁ is transferred to the shift register 161 of the array driver 160 by the clock signal CLK. After one column of data has been transferred to the shift register 161, when the charged portion of the photosensitive drum 10 reaches the erasing array 150, a latch signal LTH is output from the main processor group 71, and shift is performed in response to this signal. It is supplied to the register 162. That is, since it is disposed between the erasing array 150 and the charger 11 and the exposure section Ph, one row of data output by the memory 85 _2, for example, the angle between the erase array 150 exposed portions Ph theta
₁ and 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 θ ₁ / 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 turned on, and turned off when turned off. Therefore, of the charged portion of the photoconductor drum 10, the portion where the photosensitive element 152 is turned on is erased, and the portion where the electricity is removed is not exposed to an electrostatic latent image even after being exposed and the original image is erased. It has been broken.
Thereafter, in the same manner, the data in the memory 85 ₂ is read out column by column and the image is erased.

According to the above-described embodiment, the first carriage is provided with the pair of the light emitting element and the light receiving element as the first detecting means.
In the case where the carriage is normally placed in a standby position in the copyable range and the presence of the document is detected by the light receiving unit when the closing operation of the document cover is detected by the micro switch as the second detecting means, When the absence of the original is detected by the light receiving section by moving from the standby position in the direction opposite to the scanning start position, the scanning means is moved in the direction of the scanning start position and the output signal of the light receiving element is displaced at this time. , When the document size is detected and when the closing operation of the document cover is detected and the absence of the document is detected by the light receiving section, the document is moved from the standby position to the scanning start position,
The document size is detected by the change in the output signal of the light receiving unit at this time. Therefore, unlike the conventional case, a plurality of light emitting elements and light receiving elements are not required, so that the number of parts can be reduced and the space for arranging parts can be reduced.

Further, the size of the document can be detected accurately and reliably from the state where the first carriage shows the copyable range.

Further, the spot light source 131 as the first detecting means to the first carriage 41 _1, movable light receiving portion 132 in a direction perpendicular to the first movement direction of the carriage _411, the change in the output signal of the light receiving portion 132 Accordingly, the document size is detected. Therefore, the sizes of the document in the x direction and the y direction can be detected at the same time. Moreover, this detected x,
Since the optimum copy magnification is calculated from the size of the original in the y direction and the size of the selected paper, it is easy to copy not only fixed-sized originals but also fixed-sized originals without missing the original image. It is possible to

Further, the spot light source 131 can specify and erase an unnecessary portion of the document. Therefore, it is convenient for editing the copied image.

Further, a spot light source 131 is provided on the first carriage 41 ₁ .
Since the spot light source 131 is also used for detecting the size of the original and designating the erasing range of the original, it is possible to effectively use the space and prevent the apparatus from becoming large.

Further, since the size of the document is detected while the document cover is in the open state to the closed state, the amount of light incident on the light receiving portion largely changes between the portion with the original and the portion without the original. Therefore, it is possible to improve the detection accuracy of the document size. Moreover, since the spot light source and the light receiving unit are operated in a direction away from the original end portion of the document cover with the closing operation of the document cover, it is possible to gain time for releasing the document cover.

Further, since the document size is detected in response to the closing operation of the document cover, the document size can be detected, and after the detection, the transition to the copying operation can be performed quickly, and the operability is good. .

In addition, since the first carriage normally stands by at one end of the document table apart from the fixed scale, the document size can be promptly detected in response to the scanning of the check key or the automatic scaling key.

Further, unlike the conventional case, since a plurality of light emitting elements and light receiving elements are not required, the number of parts can be reduced, and moreover, since the first carriage is provided with the light emitting section and the light receiving section,
This has the advantage that the space for disposing parts can be reduced.

Although the micro switch is used as the second detecting means in the above-described embodiment, the present invention is not limited to this, and it is also possible to use, for example, a photo coupler or the like that optically detects the operation of the rotator.

Further, the arrangement of the erasing array is not limited to between the charger and the exposure section, but as shown in FIG. 14, the erase array is arranged between the exposure section and the developing machine, and the formed electrostatic latent image is designated. It can also be configured to erase.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an image forming apparatus capable of accurately and reliably detecting the size of a document with a simple configuration.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIGS. 1 and 2 are plan views for explaining the operation, FIG. 3 is a perspective view showing only a main part of an image forming apparatus, and FIG. FIG. 5 is a side sectional view showing the structure of the spot light source and the light receiving portion, FIG. 5 is a plan view for explaining the operation of the document cover, and FIGS. 6 to 8 show the erasing range designation operation of the document using the spot light source. FIG. 9 is a plan view for explaining, FIG. 9 is a side sectional view of an essential part 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. 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 side sectional view of the main part 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. , FIG. 18 is a perspective view showing the configuration of the drive unit, FIG. 19 is a perspective view schematically showing the drive mechanism of the optical system, FIG. 20 is a perspective view showing the overall control circuit, and FIG. FIG. 22 is a block diagram of a processor group, FIG. 22 is a block diagram of a first sub-processor group, FIG. 23 is a block diagram of a second sub-processor group, FIG. 24 is a schematic block diagram showing a control circuit of a pulse motor, and FIG. FIG. 4 is a diagram for explaining a speed control direction of a pulse motor. 1 ... Main body, 2 ... Document stage, 10 ... Photosensitive drum, 30 ...
… Operation panel, 30a-30d …… Operation keys, 30e …… Position designation keys, 30f, 30g …… Erase range designation keys, 41 ₁ …… First carriage, 53 …… Scale, 71 …… Main processor group, 85 ₁ , 85 ₂ …… Memory, 131 …… Spot light source, 131a
...... Light emitting element, 132 …… Light receiving part, 132b …… Light receiving element, 135
...... Pulse motor, 140 ...... Micro switch, 150 ……
Erase array, 152 ... Light emitting element, 160 ... Array driver,
P: paper, ph: exposure section.

Claims (1)

[Claims] 1. An original table on which an original is placed, and an image of the original placed on the original table is exposed and scanned from a predetermined exposure scanning start position, and an exposure scanning start position is set during non-exposure scanning. And an image forming unit for forming an image of the original document exposed and scanned by the exposure scanning unit, and an opening / closing unit that is openable / closable with respect to the original plate. A cover means for covering the document, a first detecting means provided on the exposure scanning means for detecting the presence / absence of an original placed on the original table, and an opening / closing operation of the cover means with respect to the original table. The second scanning means, and the second scanning means detects the closing operation of the cover means, and the first scanning means detects the presence of a document, the exposure scanning means performs the exposure scanning. It is controlled so as to move in the direction opposite to the start position, and when the second detecting means detects the closing operation of the cover means and the first detecting means detects the absence of the original document, Control means for controlling the exposure scanning means to move in the direction of the exposure scanning start position, and the detection result of the first detection means when the control is performed on the exposure scanning means by the control means. The image forming apparatus comprises: a determining unit that determines the size of the document placed on the document table by referring to.