JPS61156248A - Image forming device - Google Patents

Abstract

PURPOSE:To easily and highly accurately detect the size of an original, by providing a photodetector to the carriage of an exposure lamp upper a slidable condition and moving the photodetector in the original scanning direction and another direction normal to the original scanning direction. CONSTITUTION:A photodetecting means composed of a light emitting section 131 and light receiving section 132 is provided to the guide shaft of the carriage 411 of an exposure lamp under a condition where the means can be slid in X-direction. When an original cover is closed from a position at which the cover is further opened than normal, a prescribed switch is turned on and the carriage 411 is moved at a high speed from the point D1 to another point D5 shown in the figure. When the carriage 411 is moved, the light receiving section 132 is turned on at the point D2 and turned off at the point D3. The size of an original in X-direction can be detected from the pulse number of a X- direction driving motor during the movement of the carriage 411 between the points D2 and D3. Moreover, the size of the original in Y-direction can be detected from the pulse number of a carriage motor during the movement of the carriage 411 between the points D2 and D5. Therefore, the size of the original can be detected easily and highly accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus applied to, for example, an electronic copying machine.

[Technical background of the invention and its problems]

As is well known, in electronic copying machines, a detection means has been developed that automatically detects the size of a document set on a document table (transparent glass).

This detection means includes a double-sided light-emitting element and a light-receiving element arranged along the longitudinal direction on the back side of the document table, and irradiates light in the direction of the document table with the light-emitting element while the document cover is closed. The size of the original is detected by detecting the reflected light from the original set on the original platen and the reflected light from the original cover using a light receiving element, and by detecting the portion where the level of the output signal of these light receiving elements changes. It is something.

By the way, in the case of the above-mentioned conventional configuration, it is necessary to arrange light-emitting elements and light-receiving elements corresponding to the size of the original on the back side of the document table, so many light-emitting elements and light-receiving elements are required.
It was also difficult to secure space for these devices.

Furthermore, since the surface of the document cover facing the document table is white,
If the above detection operation is performed with the document cover closed, there is no difference in the amount of light reflected from the document and the light reflected from the document cover, so it is difficult to reliably detect the document size. there were.

[Objective of the Invention] This invention has been made based on the above circumstances, and its purpose is to have a simple configuration, requiring less space for parts, and to be able to adjust the size of a document in both directions with high precision. In addition, it is an object of the present invention to provide an image forming apparatus that can be detected by easy operation.

[Summary of the invention]

In the present invention, for example, a first carriage constituting the scanning means is provided with a first detection means consisting of a pair of light-emitting element and light-receiving element driven in a direction perpendicular to the moving direction of the carriage. The carriage is kept on standby on the opposite side of the fixed scale that serves as a reference for setting the original, and when the second detecting means detects that the original cover is further opened from the normal open position when the original size is detected, the first The cartridge and the second detection means are operated to detect the size of the document.

[Embodiments of the invention]

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

6 and 7 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 2□ that serves as a reference for setting the document, and furthermore, near the document table 2, there is a document cover 11 that can be opened and closed, and a work table 1. is provided. The original set on the original platen 2 is moved back and forth in the direction of arrow a along the bottom edge of the original platen 2 by an optical system consisting of an exposure lamp 4 and mirrors 5 and 6°7. Exposure scanning is performed during reciprocation. In this case, mirror 6.7 moves at half the speed of mirror 5 so as to keep the optical path length constant. Reflected light from the original by the scanning of the above optical system, the light exposure lamp 4
The reflected light from the original due to the light irradiation is reflected by the mirrors 5 and 6.
, 7, and then the variable magnification lens block 8
The document is further reflected by mirror 9 and guided to photoreceptor drum 10, so that an image of the document is formed on the surface of photoreceptor drum 10.

The photosensitive drum 10 rotates in the direction of arrow C, and first
The surface of the document is charged 1 by the IT charger 11, and then an electrostatic latent image is formed by exposing the image of the document to slit light. It is now visualized. 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 feed roller 15 or 16, passes through the paper guide path 17 or 18, and then passes through the registration roller. The paper is guided to a roller pair 19, and sent to a transfer section by this roller pair 19. Here, each of the above paper feed cassettes 13.1
4 is removably provided at the lower right end of the main body 1, and either one 61 can be selected on the operation panel described later. Note that each of the paper feed cassettes 13 and 14 has a cassette size detection switch 60. ．． 60. The cassette size is detected by This detection switch 60. ．． 60. is composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

On the other hand, the paper P sent to the transfer section comes into close contact with the surface of the photoreceptor drum 100 at the transfer charger 20, so that
The toner image on the photosensitive drum 10 is transferred by the action of the charger 20. The transferred paper P is peeled off from the photoreceptor drum 10 by the action of the peeling charger 21 and conveyed on the conveyor belt 22, and sent to a pair of fixing rollers 23 as a fixing device provided at the terminal end of the conveyor belt 22. By passing through this, the transferred image is fixed. Then, the paper P after fixing is
The paper is discharged onto a tray 25 outside the main body 1 by a pair of paper discharge rollers 24. After the photosensitive drum 10 has been transferred, the charge is removed by a charger 26, residual red toner is removed by a cleaner 27, and afterimages are erased by a charge remover 28 to restore the drum to its initial state. It's starting to go back. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

FIG. 8 shows the operation/main channel 30 provided on the main body 1. SO, is a copy key that commands the start of copying, 30
．． 30 is a numeric keypad for setting the number of copies, etc. 30 is a display section that displays the operating status of each section and paper jams, etc.;
4 is a cassette selection key for selecting upper and lower paper feed cassettes 13 and 14; 30. 30 is a cassette display section for displaying the selected cassette; 307 is a magnification setting key for setting the magnification and reduction magnification of copies in a predetermined relationship; is a display section that displays the set magnification, SO is a density setting section that sets the copy density, 30a is a check key operated to check the original size, 30b is a check key for checking the original size t-1 This checked Automatic magnification keys 3oc and 30d, which automatically determine the copy magnification so that the image of the original is copied according to the paper size, are light-emitting light indicating elements that indicate that the check key 30a1 and the automatic magnification change key sob have been operated. .

FIG. 9 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 changing the magnification. A mirror motor 32 is a motor for changing the distance (optical path length) between the mirror 5 and the mirror 6.7 for changing the magnification. 33
is a scanning motor, which includes the exposure lamp 4 and the mirror 5;
This is a motor for moving the mirror 6.2 for scanning the original. A shutter motor 34 is a motor for moving a shutter (not shown) for adjusting the charging width of the photosensitive drum 10 by the charger 11 during zooming. A developing motor 35 is a motor for driving the developing roller of the developing device 12 and the like. A drum motor 36 is a motor for driving the photosensitive drum 10. A fixing motor 37 is a motor for driving the paper conveying path 22, the pair of fixing rollers 23, and the pair of paper ejecting rollers 24. A paper feeding motor 38 is a motor for driving the delivery rollers 15 and 16. Reference numeral 39 denotes a paper feed motor, which is connected to the registration roller pair 19.
This is a motor for driving. A fan motor 40 is a motor for driving the cooling fan 29.

FIG. 10 shows a drive mechanism for reciprocating the optical system. That is, the mirror 5 and the exposure lamp 4 are placed in the first carriage 411, and the mirror 6.7 is placed in the second carriage 41. ), these carriages 41□.

418 is guide rail 4jl+4'! Guided by arrow a
It can be moved in parallel in any direction. That is, the 4-phase/f pulse motor 33 drives the Zori 43. An endless belt 45 is stretched between the pulley 43 and the idle pulley 44, and one end of the first carriage 4 that supports the mirror 5 is fixed to a midway portion of the belt 45.

On the other hand, the rail 42. of the second carriage 41, which supports the mirror 6.7. The guide portion 46 of the rail 42. Two pulleys 47°41 are rotatably provided at a distance in the axial direction of the pulleys 47! , 47, a wire 48 is stretched between them.

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 male coil spring 50, respectively. Further, one end of a first carriage 411 is fixed to a midway portion of the wire 48. therefore,
As the Noculus motor 33 rotates, the belt 45
rotates and the first carriage 41. moves, and the second carriage 41 . also move. At this time, Sea I
) 4f/, 47 serves as a movable pulley, the second carriage 41. move in the same direction at the same speed.

In addition, 1. Second carriage 41. ．． 41! The moving direction of the pulse motor 33 is 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 l par ), and the magnification setting key 3
0. ．． 30. If K is the copy magnification specified by , then the copyable range (x, y) is x = Px / K y = Py / K. Of this copyable range (x, y), the X direction corresponds to the lateral direction of the document table 2, and the y direction corresponds to the longitudinal direction of the document table 2.

FIG. 11 shows the overall control circuit, in which the main processor group 71 and the first . 2nd set 7″μ set set 72.7
It is mainly composed of 3. The above main processor group 71
, the operation panel 30 and various switches and sensors, such as the case and size detection switches 601, 60. A high-voltage transformer 76 that detects inputs from input devices 75 such as, and drives the various chargers, the static elimination lamp 28, the platen lenoid 27a of the cleaner 27, the heater 23a of the fixing roller pair 23, the exposure lens 4, and The motors 31 to 40.58 are controlled to perform the above-described copying operation, and the light-emitting element 131h and light-receiving element 1321 constituting a light-emitting section 131 and a light-receiving section 132, which will be described later, serve as first detection means. The document size is detected by controlling a pulse motor 135 that drives the document size, microswitches 140 and 141.degree. memory 85 as second detection means.

Among the above motors 31 to 40, motor 35°37.40
and a toner motor 7 that supplies toner to the developing device 12.
7 is controlled by the main processor group 71 via a motor driver 78, motors 31 to 34 and 135 are controlled by the first sub processor group 72 via a pulse motor driver 79, and motors 36, 38, and 39 are controlled by the first sub processor group 72 via a pulse motor driver 79. The second sub-processor group 73 via the motor driver 80
controlled by Further, the exposure lamp 4 is controlled by the main processor group 71 via the lamp regulator 81, and the heater 23 is controlled by the main processor group 71 via the heater control section 82. And the main presser! #
71 to 1st. Commands to drive and stop each motor are sent to the second sub-processor group 72 and 73, and the first... Second Sano Processor Group 7f2. A status indicating the drive/stop state of each motor is sent from r3 to the main processor group 71. The first sub-processor group 72 also includes motors 31 to 31.
Position information from a position sensor 83 that detects each of the 34 initial positions is input.

FIG. 12 shows an example of the configuration of the main processor group 11. That is, 91 is a one-chip microphone-computer (hereinafter simply referred to as a microcomputer), and the input/output y
et'-)! Via 92, operations (not shown), human force detection of keys on the armpits, various light display controls, etc. are performed. Furthermore, the microcomputer 91 is expanded with input/output ports 93-96. The input/output port 93 has a high pressure transformer 6.
, a motor driver 78, a lamp regulator 81, and other outputs, an input/output port 94 is connected to a size switch for detecting the paper size, and its respective input, and an input/output port 95 is connected to a copy condition setting switch and its input. Individual inputs are connected. Note that the input/output port 96 is for an option.

FIG. 13 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. Reference numeral 102 is a programmable interval timer for controlling the phase switching interval time of the arm motor, and when a set value is set from the microcomputer 101, the count value is set based on the set value.
When the count is out, it is output to the interrupt line of the microcomputer 101 indicating the end of the count. The reference clock i4 pulse is input to the timer 102. Also, microcomputer 101
, to which position information from the position sensor 83 is input and input/output ports 103 and 104 are connected.

The motors 31 to 34.135 are connected to the input/output port 104 via the pulse motor driver 79. In addition, the input/output ports 103 mentioned above are each No. 4? The main processor f
It is used when outputting to lprl.

FIG. 14 shows an example of the configuration of the second subgrocer group 73. That is, 111 is a microcomputer, which is connected to the main processor group 71. Reference numeral 112 is a programmable interval timer for controlling the phase switching interval time of the motor.
When the count is out, a termination pulse is output. This termination pulse is latched by the latch circuit 113, and its output is supplied to the interrupt line of the microcomputer 111 and the input/output port input line.

Further, an input/output port 114 is connected to the microcomputer 111, and the motors 36, 38, and 39 are connected to the input/output port 114 via the Norf motor driver 80.

Fig. 15 shows the pulse Tanabata control circuit, with input/output port 121 (input/output port 1 in Fig.
04,114) has a 4' motor driver 1.
22 (in Figure 10) + Luss motor driver 19.80t
IC equivalent) is connected to this pulse motor driver 12.
2fC pulse motor 123 (the pulse motors 31 to 3
4゜se, ss, ss phase"k) 0 each volume 1Rh, h, m
.

i is connected.

Figure 16 shows the pulse Tanabata speed control method.
(a) Is the diagram NoJ? (b) is the speed curve of the Luss motor;
The figure shows the phase switching interval. As is clear from this figure, the phase switching intervals are long at first, gradually shorten, and then become equal intervals, p1, gradually lengthen again, and then stop. That is, this indicates the through-up and through-down of the pulse motor, starting from the self-starting region, starting up, being used in the high-speed region, and then eventually falling down. In addition, 11.1.・・・
-tX indicates the phase switching interval time.

Next, the main parts of this invention will be explained. In FIGS. 2 to 4, the first carriage 411 includes a light lamp 4.
The guide shaft 1 is moved along the exposure lamp 4 to the part where the light has been traced.
30 are provided. This guide shaft 130 has a light emitting section 131 as a first detection means for detecting the size of the document.
゜The light receiving section 132 is provided integrally and movably.

These light emitting parts 131. As shown in FIG. 4, the light receiving section 132 is arranged such that the optical axis of the light emitting section 13 is perpendicular to the document table 2, and the optical axis of the light receiving section 132 is located on the surface of the document table 2.
It is arranged at an angle so as to intersect with the optical axis of No. 3. Of these, the light emitting unit 131 guides the light emitting element 131a and the light generated by the light emitting element 131a toward the document table 2.
The light-receiving section 132 includes a light-receiving element 132*, and a lens 132b that guides the reflected light from the document table 2 to the light-receiving element 132a. The lighting signal of the light emitting element 131a is sent to the main processor group 7.
1, and the output signal of the light receiving element 132a is supplied to the main processor group 7.

Further, the light emitting section 131 and the light receiving section 132 are connected to a timing belt (toothed belt) 134 disposed along the guide shaft 130. This timing belt 134 is passed between a pulley 136 and a driven pulley 137 provided on the rotating shaft of a starter gear 135.

Therefore, by rotating the main pulse motor 135, the light emitting section 131. The light receiving section 132 is connected to the first carriage 41
, is moved in a direction perpendicular to the scanning direction of . In addition, a first
The carriage 411 includes a light emitting section 131. If a position sensor 138 consisting of a microswitch is provided to detect the initial position of the light receiving section 132 and the light receiving section 132 is moved, for example, the light emitting section 131°, the lower end of the light emitting section 131 is first moved to the position sensor 138. The initial position is detected by contact 12.

On the other hand, as shown in FIG. 1, a rotator 1. is located inside the main body 1 at the base end of the document cover 1□ and rotates together with the document cover 1□. is provided. This rotating element 1.
The four microphones f140 and 141 are located near the microphones f140 and 141 as second detection means for detecting the open/closed state of the document cover 1□.
is provided. These microswitches 140.1
The arrangement position of 41 is determined as follows. That is, the microswitch 140 sets the document cover 11 to the maximum opening angle θ.
At an opening angle θ1 smaller than max, the rotator 1. The microswitch 141 is located at a position where the document cover 11 is turned on when the rotator 1. The switch is located at the position where it is turned on. The document cover 11 is normally open.
- In the open state, the open state is held at the open angle θ by a holding member such as a spring (not shown).

The operation of the above configuration will be explained using FIGS. 1 and 5. Normally, the first carriage 41m is located at the farthest position from the fixed scale 21, as shown in FIG.
The first detection means is placed on standby at one end in the longitudinal direction of the document table 2, and the first detection means is placed on standby with the light emitting section 13 located at the center of the document table 2 in the width direction. In this state, when the document cover 1□ is opened, the document cover 11 is held at the opening angle θ□, and the microswitch 140 is turned on. The main processor group 71 uses the output signal of the microswitch 140 to control the document cover 1. An open state is detected. After this, fixed scale 2. Document G using the center part as a reference.
Sera) 1. , for example, operate the check key J□JL. Then, as shown by arrow 0, when the document cover 11 is further opened to the opening angle θ and then closed, the opening angle θ is
, the microswitch 141 is turned on. In the main fO processor group 21, this micro switch f141
F) Light emitting unit 1310 light emitting element 131 according to the tB force signal
A lighting signal is supplied to the first carriage 41 .a to the sub-processor group 72 . A high-speed drive command signal is supplied. Therefore, the light emitting element 131a is turned on, and the first carriage 411 moves in the direction of the fixed scale 2□ at the same speed as the return operation during normal copying.
It is moved at a higher speed than the scanning speed during copying. Accordingly, the light emitting section 13 and the light receiving section 132 are moved from point 08 to point 1, as shown in FIG. Most of the light emitted from the light emitting unit 131 passes through the M stacking table 2 from the eight points to the three points located on the edge of the set document GO.

Tsumashi, first carriage 41. Since the speed at which the document cover 11 moves from the edge 8 point toward the DI point is set faster than the speed at which the document cover 11 normally rotates between the open angles 02 and 4, the light emitting unit 1
31 and the light receiving section 132, and the document cover 1□ is open until it reaches the point. Therefore, the light emitting part 1
31 and the light receiving section 132 move from point 8 to point 5, most of the light emitted from the light emitting section 131 passes through the document table 2, and the light receiving element 132a of the light receiving section 132 is in an off state. It has become. Then, the light emitting section 131. Light receiving section 13
2 reaches the 08 point, the light emitted from the light emitting section 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. 1st carriage 4 □ is this glue.

The point is further moved in the direction of the fixed scale 21, and at the same time, the motor 135 is driven in response to the ON output of the light receiving cable 132a, and the light emitting section 13 and the light receiving section 132 are moved.
is moved in a direction away from the base end of the document cover 1□, as shown in FIG. Then, as shown at point 08, with the light emitting section 131 protruding from the edge of the document G, the light receiving cable 13
2& is in the off state again, and in this state, the light emitting part 1 is further turned on.
31. The light receiving portion 132 is moved toward the end of the first carriage 4□. The light emitting section 1311 and the light receiving section 132 reach the end of the first carriage 41□ at point D4 as the first carriage 41□ moves, and thereafter remain at that position.
moved to the point. In this way, from the time when the light receiving element 132a is turned on, the light emitting section 13 is turned on.

For example, if the main processor group 71 counts the number of driving noculus of the pulse motor 33 that drives the first carriage 41□ until the light receiving section 132 reaches the three points, the size of the document G in the X direction can be determined from this counted value. can be detected. Further, the document G is set at I2 with respect to the center of the document table 2, and the light emitting section 131 is positioned at the center of the document table 2 from point D1 to point D3. Therefore, from when the light receiving element 1321 is turned on until it is turned off again, the light emitting section 131. A pulse motor 135 that drives the light receiving section 132
If the number of driven balloons is counted by, for example, the main processor l\+71, the size of the document G in the X direction can be obtained by 2xE, where E is the count value.

By the way, in the above-mentioned counting method in the X direction, the document size cannot be determined unless the light emitting section 13 and the light receiving section 132 are moved from a point □ to the point 12. Therefore, the first
The number of drive pulses PSI for the carriage and the gear 411 is stored in advance in the main processor group 1, and this number of drive pulses P□
, until the light-receiving element 132IL becomes on state P1. By subtracting, the number of driving pulses P□ corresponding to the size of the document G in the X direction is Pll = pH - pt
It can be obtained as s. With this kind of configuration,
When the light emitting section 131 and the light receiving section 132 reach two points, the document size in the X direction can be detected, and the detection can be performed quickly.

When the size of the document G in the X direction and the X direction is detected in this way, the detected document size P, for example. x+
pa, the size Py of the selected paper in the X direction (paper feeding direction), and the size Px of the selected paper in the x direction (direction perpendicular to the paper feeding direction).
The optimum copying magnification K x + K y is determined in the main processor group 77 from the above. That is, this copying magnification K
x, Ky are K x = P x / Pg.

It is obtained from the relationship K y = P y / Pay . In addition, the paper size Px, Py
is stored in the memory 85 in advance.

Next, copying magnifications Kx and Ky that allow the largest number of original images to be copied onto the selected paper are selected from these. In other words, for example, if an A4 size original is set with its longitudinal direction along the fixed scale of 21tic, and a paper of size B is selected whose longitudinal direction is set along the paper feeding direction, then the X direction of the original With the copying magnification KV determined based on the size of the paper, it is difficult to copy the original image within the range of the paper unless it is an enlarged copy. Therefore, by using the copying magnification KX determined based on the size of the original in the X direction, it is possible to perform reduced copying and copy more original images onto paper than in the above case. That is, the smaller one of the damped copying magnifications Kx and Ky is selected as the optimum copying magnification.

The copy magnification selected in this way is, for example, the operation/mother channel 3.
The light display section so and yc at 0' are displayed.

In addition, when the automatic magnification change key sob is operated and the document cover 1° is closed with the document G set,
The optimum copying magnification is determined as described above, and the motors 26, 31, 32, etc. are operated according to this copying magnification, and the lens block 8 and mirror 5 are operated.
, 6 etc. are moved.

As described above, when the check key 30 & or the automatic magnification change key sob is operated, the first carriage 41□ is moved to the fixed scale 2□ side, and the light emitting section 13 and the light receiving section 132 are moved to the fixed scale 2□ side.
is stopped at a position corresponding to point D6. The stop position of the first carriage 411 coincides with the copy start position. When the check key 30m is operated and the copy key 30□ is operated, the lightless lamp 4 is lit from that position and the first carriage 41□ is moved away from the fixed scale '2□, A copy operation at the same size is performed.

In addition, when the automatic magnification key sob is operated,
When the copy key 30□ is operated, a copying operation is performed using the obtained copying magnification. When these copying operations are completed, the first carriage 411 and the light emitting section 131. The light receiving unit 132 is placed on standby at a position indicated by point D1 in FIG. Further, when a predetermined period of time has elapsed after operating the check key 30th or the automatic magnification change key 30b, the first carriage 41
12, the light emitting section 1311 and the light receiving section 132 are moved to the position indicated by 8 points in FIG. 5, and placed in a standby state.

It is assumed that the stop position of the first carriage 4 on the side of the fixed scale 2 coincides with the copying start position, but in reality, the first carriage 411 starts operating at the start of copying and then reaches a constant speed. Since a predetermined distance is required for this to occur, it is necessary to take this into consideration.

Further, during normal copying, the ON outputs of the microswitches 140 and 141 are ignored, and the copy key 30□
In response to the operation, the first carriage 41□ is first moved from point 08 toward black at high speed, and then moved toward point D1 at a normal copying speed. After copying is completed, the copying machine is stopped at point D1, as shown in FIG.

According to the above embodiment, the first carriage 411 includes the light emitting section 131 as the first detection means. A light receiving section 132 is provided so as to be movable in a direction perpendicular to the moving direction of the first carriage 41□, and the document size is detected according to changes in the output signal of the light receiving section 132. Therefore, the size of the document in the X direction and the Y direction can be detected simultaneously.

Furthermore, since the document size is detected while the document cover 11 changes from the open state to the closed state, the amount of light incident on the light receiving section 132 varies greatly depending on the portion where the document is present and the portion where there is no document. Therefore, it is possible to improve the accuracy of detecting the document size. Moreover, the document cover 1□ is first further opened from the normal open position, and in this state, the first detection means and the light emitting unit 131. Since the light-receiving section 132 is configured to start its operation, it is possible to lengthen the time until the document cover 1□ is closed, and the time required to detect the document size can be secured.

Furthermore, the light emitting section 131. The light receiving section 132 is connected to the document cover 11
Since the document cover 1 □ is moved away from the base end of the document cover 1 □ as the document cover 1 □ closes, it is possible to take advantage of the opening time of the document cover 11 .

In addition, since the document size is detected according to the closing operation of the document cover, it is possible to detect the document size and quickly move on to the copying operation after detection, resulting in excellent operability. .

Furthermore, the first carriage 41□ is normally fixed at the scale 2.
1, the document size can be quickly detected in response to the operation of the check key 30g or the automatic magnification change key 30b.

Further, unlike the conventional case, a plurality of light emitting elements and light receiving elements are not required, so the number of parts can be reduced, and the light emitting part 131. Since the light receiving section 132 is provided, there is an advantage that the space for arranging components can be reduced.

In the above embodiment, the microswitches 140 and 141 are used as the second detection means, but the invention is not limited to this, and for example, the rotator 1. It is also possible to use a photocoupler or the like that optically detects the operation of the sensor.

It goes without saying that other modifications can be made without departing from the gist of the invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, the configuration is simple and requires less space for parts, and the size of the document in both directions can be detected with high precision and with easy operation. An image forming apparatus can be provided.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the image forming apparatus according to the present invention, and is a partially cutaway side view shown to explain the operation of the document cover, and FIG. 2 shows the first detection means. tD4), a perspective view showing only the 1%' section, Fig. 3 is a side sectional view showing a part of Fig. 2, and Fig. 4 is a side view showing the structure of the light emitting part and the light receiving part. 5 is a plan view for explaining the operation, FIGS. 6 and 7 show the configuration of the image forming apparatus, FIG. 6 is an overview perspective view, and FIG. 7 is a side sectional view. 8 is a plan view showing the configuration of the operation/monitoring system, FIG. 9 is a perspective view showing the configuration of the drive unit, and FIG.
Figure 0 is a perspective view schematically showing the drive mechanism of the optical system;
12 is a block diagram showing the overall control circuit, FIG. 12 is a block diagram of the main processor group, FIG. 13 is a block diagram of the first sub-processor group, FIG. 14 is a block diagram of the second sub-processor group, and FIG. This figure is a schematic configuration diagram showing a control circuit of a pulse motor, and FIG. 16 is a diagram for explaining a speed control method of a pulse motor. 1...Copy machine main body, 11...Document cover, 2...
Original table, 21...Fixed scale, 3o...Operation number 4
30a... Check key, 3ob... Automatic magnification change key, 41□... First carriage, 11... Main processor group, 131... Light emitting section, 132... Light receiving section, 135 ...Riyarus Motor, 140.141...
·Microswitch.

Claims (1)

[Scope of Claims] 1) A document table having 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 detects the reflection from the document. In an image forming apparatus that forms an image corresponding to a light image on a transfer material, a first detection means is provided in the scanning means and detects the presence or absence of a document; The second detection means for detection and the scanning means are usually moved to one end of the document table, and the scanning means is moved toward the other end of the document table in accordance with the detection output of the second detection means. An image forming apparatus comprising: a control means for moving the document and detecting the size of the document from the output signal of the first detection means. 2) The first detection means comprises 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 document cover has a rotator at its base end that rotates together with the document cover, and the second detection means is disposed in front of the maximum rotation angle of the rotator and is operated by the rotator. The image forming apparatus according to claim 1, comprising a plurality of microswitches. 4) The image forming apparatus according to claim 1, wherein the scanning means is moved faster when detecting the size of the original than when scanning the original.