JPS6323144A - Original platen moving mechanism - Google Patents

Abstract

PURPOSE:To prevent the occurrence of bending, etc., in an original placing table so as to obtain proper moving accuracy and to make accurate reciprocating movement of the table, by providing a 1st and 2nd guide means, a driving means, a detecting means, and a control means. CONSTITUTION:Rear guide rails 70 are composed of a lower rail 79 fixed to a rear frame 50, upper rail 81 fixed to the rear angle 77 of an original placing table, and retainer which is positioned at the center of the rails 79 and 81 and has a metallic ball 80 held in a rotatable state, and control the position of the rear angle 77 of the original placing table in the up-down and front-rear directions. Moreover, by putting the protruding section 3 of the front angle 78 of the original placing table between guide rollers 76 and 75, the position of the original placing table in the vertical direction is controlled. Therefore, the reciprocating movement of the original placing table is made very smoothly irrespectively of the manufacturing error and assembling error of the machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field of the Invention] The present invention relates to a mechanism for moving a document table used in a copying machine or the like.

[Prior art]

2. Description of the Related Art Conventionally, there has been known a copying apparatus in which a document to be copied is placed on a transparent flat document table and the document table is moved to perform copying.

In an apparatus that copies a document by moving the document table in this manner, the document table needs to be guided in its movement with high precision so that the document table does not bend or become distorted.

This deflection and distortion of the original table has a large effect on the copied image and causes image disturbance.

In addition, the original 1lii table can be switched from forward movement to backward movement,
Requires operation to stop at a predetermined position. This operating position,
If the operation timing is inaccurate, the image may be missing or the next image formation may be adversely affected.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a document table moving mechanism that does not cause sagging on the document table, provides accurate movement accuracy, and allows the document table to reciprocate accurately. shall be.

[Summary of the invention]

The present invention achieves the above object by moving the document table of an apparatus having a document table on which a document is placed and moved back and forth, and a main body to which the document table is attached and which houses an illumination means for illuminating the document. In the mechanism, there is a first plate that regulates the vertical and front-back directions of the document table to guide the movement of one end of the document table.
a second guide means for guiding the movement of the other end of the document table and regulating only the vertical direction of the document table; and a driving means for driving the document table on the first guide means side. The present invention includes a detection means provided on the first guide means side for detecting the position of the document table, and a control means for controlling driving of the document table by the drive means based on the detection result from the detection means. This is a characteristic feature.

[Embodiments of the invention] Embodiments of the present invention will be described below based on the drawings.

(Overview) The apparatus of this embodiment uses an endless photoreceptor and a more effective control method. When an endless photoreceptor is used, the return time of the document table or optical system becomes a total loss time. Therefore, in order to increase copying efficiency, the above-mentioned quick reversal is essential, and the control of the copying cycle is also required, as in the case of conventional edged photoconductors (such as setting the home position of the drum for each revolution of the photoconductor). Controlling the cycle is extremely wasteful.For this reason, this device uses a drum with an endless photoreceptor, and a drive device for the photoreceptor that controls the rotation of the photoreceptor drum.
It has a regularly spaced pulse generator, and each cycle is controlled by the pulses and an associated counter device. For example, the clock pulse generator described above generates 1 pulse per rotation of the drum.
It is configured to generate 5.75 pulses. By doing this, the drum can make one complete revolution and slightly overturn when the counter counts 16 clock pulses. This eliminates unprocessed parts of the photoreceptor before and after the copying cycle in the pre-treatment or post-treatment steps described below, and therefore, the advantage of the endless drum is that the copying process can be started from any part of the photoreceptor. is possible.

(Pre-treatment) l) Pre-exposure: The photoreceptor has different photosensitivity characteristics depending on its prior history of light irradiation, and therefore the sensitivity of the photosensitive plate is different between the first copy and the second copy. Therefore, by uniformly exposing the photoreceptor to light prior to forming a latent image on the photoreceptor, the characteristics of the photoreceptor plate are made the same for the first sheet and subsequent copies due to the fatigue effect of the photoreceptor.

2) Furthermore, as described below, if the toner is left unattended after copying, toner may stick to the contact area between the cleaning blade and the photoreceptor, and in this case, it may be necessary to clean this prior to the copying cycle. .

(Post-processing) Since the photoreceptor receives high-voltage charging with various potentials,
The surface potential and polarity of each part of the photoreceptor are different, and if left in this state, it will have an adverse effect on the characteristics of the drum, so it is desirable to remove static electricity from the surface using, for example, an AC corona at the end of the copying cycle.

Furthermore, in the case of a conventional edged photoreceptor (such as a drum that stops at a fixed home position), since the stopping position is always constant, the effects of corona charging will accumulate in the same part, and the drum will stop at a certain home position. Since the cleaner is pressed against the drum with considerable pressure 1, it is inevitable that the same part of the photoreceptor will undergo physical deformation.However, drum 1
By generating an appropriate lock pulse for each rotation, it is possible to avoid cumulative negative effects such as those mentioned above due to the drum's stop position and even start position changing moment by moment. Contributes to longer service life. In addition, the copy cycle is not controlled by the rotation of a drum or related control means as in the past, but is based on an inverted signal corresponding to the copy size of the document table or optical system, and is controlled by a clock pulse and a counter. Reliability is improved by using a digital circuit with an effective circuit system, such as reversing signals from the document table or optical system, or resetting the black and pulse counters at the end of post-rotation. Furthermore, it serves as a jam detection means for monitoring delayed accumulation of copy paper using a clock count (switching the number of clock counts according to the copy size as necessary) and a signal from a copy paper detector installed at the exit of the fixing unit. It uses an extremely simple and effective circuit.

Furthermore, even if the power switch is turned off during the post-processing period, a means for retaining the power until the post-processing is completed is provided by a non-contact circuit, and the entire control circuit also uses non-contact type elements. In combination with the digital circuit, reliability can be increased and lifespan can be extended.

In addition, in place of the microswitches that are conventionally used in this type of equipment, position detection devices that use non-contact type magnetic detection elements are often used.These include liquid level detection devices, clock pulse generators, copy The command button, document platen home position, paper feed start timing signal generation position, B5 size inversion position, A4 size inversion position, and B4 size inversion position are all used for the position detection devices. Magnets are attached to the movable parts to move the magnets. The following effects can be obtained by using this in a device that detects changes in magnetic flux temperature at specific locations using the Hall effect or the effect of changes in semiconductor resistance due to magnetism.First of all, the following effects can be obtained. Compared to position detection devices that use contact type elements such as switches and reed relays, contact type elements, or pairs of light emitting elements that use light as a medium, there are no contact failures, the installation is less accurate, and there is less resistance to dirt caused by toner, etc. These advantages make it possible to improve reliability and extend service life.Furthermore, as will be described later, in this embodiment, since a digital IC is applied to the control circuit, the above-mentioned devices that serve as various signal generation sources are free from the rotary phenomenon. Another advantage is that it does not occur.This circuit also uses a digital IC.
Using this technology, we are able to reduce the size of conventional relay-based control circuits, increase their reliability, and increase flexibility for complex sequences. Furthermore, the reliability of switching elements for energizing each terminal element in accordance with a control signal has been improved by using semiconductor switching elements such as thyristors and transistors, instead of conventional relay-based switching elements. As is well known, digital ICs and semiconductor switching elements have a great effect on relays because they are free from the drawbacks of relays, such as contact failure, large size, and high cost.

The present invention uses non-contact non-contact type elements and other solid-state elements as described above to more effectively combine these elements as a control circuit in each of the circuits shown below, thereby solving some of the problems unique to conventional copying machines. It is possible to solve this problem and to construct a more reliable copying machine control circuit.

(Explanation of device operation) Next, the operation of the copying machine will be explained with reference to FIGS. 1 and 2.

The copying machine of this embodiment employs a digital circuit and is controlled by clock pulses, thereby making it possible to take advantage of the features of this machine as will be described later.

First, when the main switch 10 is turned on, a very short period of time (approximately 1 second in this case) has elapsed due to the use of a digital circuit to reset the controller and start up other electrical systems. 15 starts rotating. As mentioned above, a clock pulse generating mechanism is provided in a part of the drive system so as to generate about 16 tarok pulses per rotation of the photosensitive drum. When the photosensitive drum 15 begins to rotate, the drum first rotates approximately once for 16 clock pulses (hereinafter referred to as 16CPetc). This can be considered a step before starting the copying process (this is to obtain a high-quality copy when the copying process starts, and may be omitted. If the copy button 13 is not ON, the photosensitive drum is Although it stops after rotating once, if you turn on the copy button 13, the copying process will begin.

First, the photosensitive drum 15 rotates by an amount of 16 CP plus 4 CP when the copy button is turned on, and only then does the document table 2 with the document placed on the document table glass 5 start, and is illuminated by the illumination lamp 16. The image is formed on the drum 15 at an exposure section 19 by a reflecting mirror 17 and an in-mirror lens 18 .

The surface of the photosensitive drum 15, that is, the photosensitive layer covered with a transparent insulating layer, is first charged to 100% by a corona current from a positive charger 21 to which a high voltage of 100% is supplied from a high voltage power supply 20. Subsequently, when reaching the exposure section 19, the image of the subject illuminated by the illumination lamp 16 is slit-exposed onto the photosensitive drum 15, as described above. At the same time, AC high voltage is being supplied from the high voltage power supply 20. A.C.
AC charging is performed by a charger 22. Then, a high-contrast electrostatic latent image is formed on the drum surface by the next full-face exposure using the full-face exposure lamp 23, and the next development process begins. The developing device 24 includes a container 26 for storing a developing solution 25, a pump 27 for stirring the developing solution and pushing it up to the developing electrode section, a developing electrode 28, and a device for removing the fog when the image developed on the drum has a fog. , consisting of an electrode roller 29 rotating in close proximity to the drum, the - side being grounded.

The developing electrode 28 is always kept at a constant level on the photosensitive drum 15, and the electrostatic latent image formed on the photosensitive drum 15 is absorbed by the developer 25 pushed up onto the developing electrode 28 by the pump 27. It is developed with toner and visualized.

Next, the photosensitive drum 15 is charged with a high voltage by the post charger 30, and the excess developer on the photosensitive drum 15 is squeezed out without disturbing the image. Next, the transfer paper 7 fed from the paper feed unit is brought into close contact with the photosensitive drum 15, and the transfer charger 31 charges the photosensitive drum 15 with an electric field generated by the + high voltage from the power supply 20.
The upper image is transferred onto transfer 7. After the transfer, the transfer paper 7 is separated by a separation belt 32 and guided to a drying and fixing section 33. The photosensitive drum 15 is pressed against the blade cleaner 3
The remaining toner developer is wiped off at the edge portion 35 of 4.
Repeat the next cycle again. The developer wiped by the blade cleaner 34 is guided to the developing device 24 through grooves 36 (shown in the third figure) provided at both ends of the photosensitive drum 15, and is used again for development.

Here, turn on the main switch 10 mentioned earlier and
To explain why the document table 2 only begins to move after the drum has rotated by an amount equivalent to CP, and the drum has rotated by 16 cP - = 4 CP, this machine uses an endless type drum as the photosensitive drum. Therefore, any surface of the photosensitive drum can contribute to image formation. Therefore, when it comes to increasing the number of copies per unit time by eliminating unnecessary rotation as much as possible, first of all, if there is any residual toner in the blade cleaner edge 35 of the first drum, then this machine For example, if the photosensitive drum is not used for a week or ten days, it may dry out and become stuck to the drum in the worst case, and in that case, it is necessary to clean the photosensitive drum before forming a latent image.

Next, there are 4 CP worth, which is because in the copying process mentioned earlier, there are 10 charging processes etc. before the slit exposure.
This process is based on the fact that it is better to avoid this when making the first copy, as this will make the machine more reliable.

Next, the transfer paper 7 is housed in a cassette 6 and is removably mounted by fitting the cassette 6 into the paper feed section at the lower left of the machine. Various cassettes are prepared according to the sizes of several types of transfer paper, and can be easily replaced as necessary.

The transfer paper 7 is placed on a middle plate 37 inside the cassette 6, and a spring 38 pushes up the middle plate 37, so that the transfer paper 7 is always separated by separation claws 39 provided on both sides of the tip of the cassette 6.
is being forced on. At this time, by appropriately selecting the spring constant of the spring 38, the force with which the transfer paper 7 is pressed against the paper feed roller 40 during paper feeding is made almost constant, regardless of the amount of transfer paper 7 in the cassette 6.

When the original platen reaches a predetermined position, an operating piece fixed to the original platen side activates the detection means on the main body side and a signal is output, and the constantly rotating paper feed roller 40 descends and enters the cassette 6. The transfer paper comes into contact with the uppermost transfer paper, and by the movement of the separating claw 39, one copy of the transfer paper is separated and sent out from the cassette 6.

However, the register rollers 41 and 42 in the immediate vicinity are
Since it stops at the same time as the paper feed roller 40 descends, the cassette 6
The transfer paper 7 sent out from the transfer paper 7 creates a slack between the guides 43 and 44 with its leading edge touching the contact portion of the register rollers 41 and 42. Then, when the paper feed roller is about to rise, the register rollers 41 and 42 rotate again in time with the leading edge of the image on the photosensitive drum, and the transfer paper 7 is sent at a speed that matches the circumferential speed of the photosensitive drum 15. .

As described above, the transfer paper 7 is brought into close contact with the photosensitive drum 15, the image on the drum 15 is transferred onto the transfer paper 7 by the transfer charger 30, and the transferred paper 7 is separated from the drum 15 by the separation belt 32. The toner passes through the drying and fixing section 30 and is fixed on the transfer paper 7, and is then transferred to the discharge roller 45. 46 , the paper is discharged onto a discharge tray 47 .

Next, the operation for copying will be explained with reference to FIGS. 2 and 3. Place the original to be copied on the original table glass 5 with its leading edge aligned with the leading edge A of the glass, and press the holding cover 3 (second
(Fig.) and press the copy button 13 (Fig. 2).
The drum starts rotating and starts working at the same time. The document table start signal after 4CP from the clock pulse generation mechanism causes the document table 2 to move to the left in FIG.
It moves in synchronization with the circumferential speed of , and performs slit exposure. When the exposure is completed, the document table 2 stops moving to the left in response to a signal from the document table 2 itself according to the size of the paper in the cassette, and immediately returns to the opposite direction, that is, to the left. The time required for this return is loss time during copying, so it is desirable that it be short. In this machine, the return speed is approximately four times the forward speed to increase copying efficiency. Since the return speed is high as described above, it is easy to cause a shock when stopping, but in this machine, the shock is absorbed by the brake mechanism described later, and the document table 2 is quickly stopped at a predetermined position.

Even when a large number of copies are to be made in succession from the same document, this can be easily done using a counting device (not shown) that is linked to the copy button 13. The counting device captures the movement of the document table 2,
Since counting is performed and the switch element is held until the set number of copies has been counted, a large number of copies can be made.

The original platen restart command during continuous copying is issued by the ICP after the original platen 2 has stopped at a predetermined home position. This is to ensure smooth movement of the document table 2 when it starts moving forward. You can also restart from any drum surface.

Further, the copying machine of this embodiment is capable of making copies of various sizes from the maximum B4 size to the minimum B5 size. In such a case, regardless of the copy size, if the document table 2 were to be moved a distance of 4 days, which is the maximum copy size, the number of copies per unit time would be small, resulting in a large time loss. Therefore, this copying machine supports each copy size, for example, A4. E5), it has a plurality of document table reversal signal generating members 48 (FIG. 4), and changes the copy cycle in accordance with each copy size,
Improves copying efficiency.

The difference in cycles depending on the copy size as described above is determined by signals from the cassettes 6 for each size.

Next, the suspension state and restart after copying is completed will be described. If you leave the power on after all copying operations have been completed, the photosensitive drum 15 will constantly rotate, and if the high voltage power is on, the photosensitive drum 15 and blade cleaner 3 may be damaged.
4. Not preferable in terms of durability. Therefore, in the copying machine of this embodiment, even after a certain period of time has passed after the completion of the copying operation,
When the next copying operation is not performed, press main switch 10.
Even if it is ON, the drum automatically stops and enters a hibernation state. This time is set longer than the time required for the transferred transfer paper 7 to be discharged outside the machine and for the entire surface of the photosensitive drum 15 to be cleaned. To make a copy during this hibernation state, press the copy button 13 on the operation section 9.
When is pressed, everything returns to the state before the pause, and after dCP, the document table 2 starts to move forward. This copying machine enters a dormant state 26 CP after the document table reversal command in the final copying process.

(Description of Structure of Apparatus) Next, the specific structure of the copying machine according to this embodiment will be explained.

49 in Figure 3. Reference numeral 50 denotes front and rear frames, which are strongly constructed by a stay (not shown) and a bottom plate 51 that connect the two frames.

A drum shaft fixing member 52 made of alloy casting is fixed approximately at the center of the rear frame 50, and a drum shaft 53 is fixed to the member 52.
is fixed.

The drum shaft fixing member 52 is fixed to the rear frame 50 with a large interval as shown in FIG. 3, and is constructed to have sufficient strength against the weight and other forces of the drum 15 even in a substantially cantilevered state. has been done. A drum gear 56 is rotatably supported on the drum shaft 53 via bearings 54 and 55. A bearing retainer 57 is fixed to the drum shaft 53 with a set screw, and serves as a retainer to prevent the drum gear 56 and bearings 54, 55 from coming off when the drum 15 is removed as described later. The other end of the drum shaft 53 (the right end in FIG. 3) is held substantially horizontally by a support plate 58. The support plate 58 is positioned by two positioning pins so that the drum can be removed as described later, and is removably fixed to the frame 49 by two wing nuts.

The support plate 58 has a thrust holding member 59 movable in the thrust direction, which pushes the bearing 61 held on the drum by a spring 60 to the left in FIG. It's Nishide.

The photosensitive drum is formed by a drum 62, a front flange 63, a rear flange 64, a guide vibro 5, two rods 66, and bearings 61 and 67 press-fitted into the front and rear flanges 63 and 64,
It is assembled by sandwiching the drum 62 between the front and rear flanges 63 and 64 and tightening it with a rod 66. The guide vibro 5 is for guiding the drum so that it can be easily attached and detached when the drum is attached and detached along the drum shaft 53. The rear flange 64 has a hole that can engage with a drive pin 68 fixed to the drum gear 56, and the two engage to rotate the drum.

As described above, by supporting the drum semi-uniformly, the drum is compactly constructed and easily assembled and disassembled while providing sufficient strength. By fixing the drum shaft 53 to the fuselage and configuring it with a hollow pipe, a heating element 69 is provided therein,
By keeping the photoreceptor at a constant temperature, it is possible to prevent moisture from condensing on the drum surface in high humidity conditions, and to obtain high quality images in low temperature environments.

At the upper end of the rear frame 50 are a guide rail 70 and control signal magnetic sensing elements 48A, 48B, 48C, 71.
The members 73 and 74 for attaching ゜72 are fixed (
Figures 3 and 4). Also, at the upper end of the front frame 49,
Guide rollers 75 and 76 as shown in FIG. 3 are installed, and cooperate with the guide rails 70 to cause the document table 2 to smoothly reciprocate. The document table has a front angle 78 and a rear angle 77 connected by a stay to form a frame, which has sufficient rigidity against various forces during forward movement, backward movement, and reversal. A transparent glass 5 is placed in the center of the frame, and other pages of the book are placed on the front of the frame (the left end in Figure 1) when copying a book, etc., so that the entire page to be copied is in close contact with the glass surface. The document table 2 is configured by a case 4 provided for the purpose of making the original document stand.

The rear guardrail 70 has a mounting member 73 on the rear frame 5o,
The document table is composed of a lower rail 79 fixed to the rear angle 74 of the document table, an upper rail 81 fixed to the rear angle 77 of the document table, and a retainer having a metal ball 80 located between the upper and lower rails and held so as to be removable. rear angle 77
The vertical and longitudinal positions (left and right in FIG. 3) are regulated. The reciprocating movement of the document table is controlled by the metal pole 80.
Guided by the transfer of On the other hand, the protruding tray portion 3 of the document table front angle 78 is sandwiched between the lower guide roller 76 and the upper guide roller 75 to regulate the vertical position of the document table. The guide rollers 75 and 76 are rotatably held by shafts 82 and 83, which are fixed to a mounting plate 84 and firmly held by the front frame 49.

As mentioned above, the rear guide rail 70 regulates the position in the vertical and front-rear (horizontal and horizontal directions in FIG. The reciprocating motion is performed very smoothly regardless of machine manufacturing or assembly errors.

A magnetic sensing element 4 is mounted on the guide rail mounting base 73,74.
8A, 71, 72.48B, 48C are fixed,
A magnet 161 attached to the document table 2. 162 to sequentially issue control signals. When the copy button is pressed and the document table 2 starts moving forward, the magnet 161 and the element 71 first issue a paper feeding command. Further, the document table moves forward, and the exposure of each copy size (B5, A4, B4) is completed, and the magnet 161
When it reaches the element 48A, 48B, or 48C, a reversal command is issued, and the document table 2 shifts from forward movement to backward movement. As the backward motion progresses and the magnet 162 reaches the element 72, the document table 2 is stopped at a predetermined position in response to a stop command.

The size switching command is issued by the cassette 6.

In this manner, correct detection can be performed by detecting the position of the document table on the side that regulates the position of the document table in the vertical and longitudinal directions.

The driving relationship will be explained with reference to FIGS. 5, 9, and 10. The main motor is driven by a sprocket wheel 85 via a chain 86 and a sprocket wheel 87, driving a drum drive shaft 89 to which a gear 88 meshing with the drum gear 56 described above is fixed at one end. 86 is a sprocket wheel 90 rotatably attached to the shaft of the electromagnetic clutch 94.
to drive. A ladder wheel 143 is fixed to the shaft of the electromagnetic clutch on the back side of the clutch 94. The ladder wheel 143 in FIG. 1O is a ladder wheel 14 fixed to the output shaft of the clutch motor 95 by a ladder chain 142.
1 is connected. A winding drum 91 is attached to the other end of the electromagnetic clutch shaft, and a document plate driving wire 92 is wound several times around the drum 91. Both ends of the wire 92 are guided by a guide bully 93, and the document plate drive wire 92 is guided by guide wires 93. It is fixed to the tip and rear end of the angle 77.

The electromagnetic clutch 94 and the clutch motor 95 are switched and driven to rotate the winding drum 91 in the forward and reverse directions, thereby reciprocating the document table 2. A gear 96 is fixed to the drum drive shaft 89, and the drive of the main motor M1 is transmitted via a gear 97 to a gear 99 fixed to the paper feed roller drive shaft 98. The main motor M1 is driven through a gear 10.0 which is integrally fixed with the gear 99, one of which drives a gear 101, and a clutch 102.
The register rollers 41 and 42 are driven through the register rollers 41 and 42. In addition, gear lOO engages with gear 103, and clutch 13
A paper feed roller control cam 139 is driven via the roller 7. A drum gear 56 (FIG. 3) meshes with a gear 106 fixed to a separation shaft 104 to drive the separation roller 106. A ladder wheel 107 is fixed to the other end of the separation shaft 104, and is connected to a discharge roller 110 through a ladder chain 108 and a ladder wheel 109. 111
is driving. A gear 113 is integrally fixed to a sprocket wheel 112 that is driven from a sprocket wheel 85 attached to the main motor M1 via a chain 86, and the gear 113 has a clock pulse generating magnet 163 (FIG. 4). Arm held 11
The magnetic sensing element l6 is fixed to the rear frame 50 by meshing with the gear 115 fixed to the rear frame 50 and rotating the magnet.
4 (FIG. 4) and the magnet generate clock pulses at regular intervals synchronized with the rotational speed of the main motor Ml. Reference numeral 138 in FIG. 4 indicates a paper feed control unit. When the copy button 13 is pressed and the document table 2 moves forward and reaches a predetermined position, a paper feed signal is output, and the constantly rotating paper feed roller 40 is activated. It descends and feeds out one sheet of transfer paper in the cassette 6.

The leading edge of the transfer paper hits the register rollers 41 and 42, which are stopped at the same time as the paper feed roller 40 descends, and the guide 1
16. A transfer paper loop appears between 117 and 117 (FIG. 1).

Then, the paper feed roller 40 rises, and the register roller 41,
42 rotates again, and the transfer paper 7 is sent into the machine at a speed that matches the circumferential speed of the photosensitive drum 15.

The document table moves forward and backward by the drive system as described above, but in the copying machine of this embodiment, in order to improve the copying efficiency, that is, to reduce the loss time during the backward movement, the backward movement speed is set to approximately the same as that during the forward movement. 4 times (
approximately 200mm/5ec).

In order to stop the document table, which moves at such a high speed, without causing a shock to a predetermined position of the machine body, this machine has a locking mechanism as shown in FIG. 12. The locking mechanism basically consists of a combination of a one-way clutch and a brake.
The lock lever position indicated by a solid line in FIG. 4 indicates the original platen and the stopped state. A pin 155 fixed to the rear angle 77 constituting the document table 2 engages with a cutout 154 of the lock lever 153. Now, when the document table 2 starts to move forward (rightward in FIG. 4) in response to the document table start command, the lock lever 153 is pushed by the pin 155 and rotates clockwise in FIG. At this time, one-way clutch 1
56 is in the release direction, so the brake disc 157 remains stopped, and the brake disc 157 and brake shoe 158 . The frictional force caused by 159 does not act as resistance to the movement of the document table 2. As the manuscript table continues to move forward,
The lock lever 153 stops at the broken line position. When the document table 2 is in a predetermined position and a reversal command is issued, the document table stops forward movement and starts backward movement, heading toward the stop position at about four times the forward movement speed. pin 15
5 engages with the lock lever notch 154 and the lock lever 1
When the brake disc 157 is rotated counterclockwise from the broken line position to the solid line position, the brake disc 157 is rotated counterclockwise via the one-way clutch 156. brake disc 15
7 is the brake shoe 158. 159 and pressure is applied by a spring 160, and this frictional force can absorb the inertia of the document table and stop the document table without giving a large shock to the document table. With this structure, there is almost no load on the document table when starting, and sufficient braking can be applied when stopping.

1 and 3, a developing device of a copying machine according to an embodiment will be described in detail. In FIG. 1, the developer 25 stored in the developer tank 26 is pumped to the photosensitive drum 15 by a pump 27.
The toner is supplied between the toner and the developing electrode 28 to visualize the latent image on the photosensitive drum 15.

After development, fog is removed from the surface of the drum by a fog removing roller 29 disposed close to the drum. Antifogging roller 2
9 is rotated by a drive source (not shown) so as to have a relative speed with the surface of the photosensitive plate, and the surface of the defogging roller is constantly cleaned by a cleaning member 118. A scraper 119 located behind the antifogging roller 29 comes into pressure contact with the photoreceptor and removes the developer from the surface of the photoreceptor plate corresponding to the separation belt, thereby preventing staining of the separation belt.

As described above, the transfer paper 7 that is sent out from the cassette, transfers the image on the photosensitive drum, and is separated from the photosensitive drum is led to the fixing section where it is dried and fixed by heat from the hot plate. Fourth
8, a cross flow fan 120 is fixed to the rear frame 50, and a first suction port 121 of the fan 120 engages with a conveying section 122 and is formed by a duct plate 123 and a hot plate 124. Air is sucked in through the opening C through the duct, and this airflow assists the separation by the separation belt 32 and improves the adhesion of the transfer paper to the hot plate. Further, the second suction port 125 is not engaged with the conveying section and performs suction from the outside.

The air outlet 126 of the cross flow fan 120 is connected to the hot plate 124
It passes through a blow-off duct 128 located above and fixed to the upper cover 127 and is led onto the hot plate, contributing to the feeding and drying of the transfer paper. As mentioned above, by performing suction and blowing with a single fan, it is effective for downsizing and reducing the cost of the device, and by forming a semi-permeable ring system, the surface of the transfer paper is not covered with saturated steam and does not dry out. In good condition.

Next, we will discuss the operation when paper feeding is defective. In the copying machine of this embodiment, the transfer paper is processed through predetermined processes (paper feeding, transfer, etc.).

The printer is equipped with a jam detection means to check whether the paper has finished separating and fixing and is ejected from the machine within a predetermined time. The system is designed to stop the machine if it is not done and prevent accidents such as fire. In FIG. 1, 129 is a light emitting element, and 130 is a light receiving element, and the presence or absence of a jam is determined by counting a predetermined pulse by the clock pulse generation mechanism from the document table reversal command and detecting the presence or absence of transfer paper. However, the details will be explained later. Therefore, pulse counting for jam determination is started following the exposure scan, so
Compared to a system in which the count results are repeatedly output as the drum rotates, a circuit for selecting the output is not required. When a jam is detected, the fuser heater turns off.
Since the main motor M stops, the drum 15 stops, but the document table 2 stops after returning to a predetermined position (home position). When the machine stops, the upper cover 127 can be opened around the hinge 131 in FIG.
is opened approximately vertically together with the duct 128 (in this state, the hot plate 1
If there is nothing left on the transfer paper 24 and a jam occurs in the fixing section, the transfer paper can be easily removed by hand by opening the upper cover 127.

Next, the main body 122 of the transfer paper conveying section including the heating plate 124 is supported by a shaft 132 together with the separating section including the separating belt 32 and the like, and is normally held in place by a locking mechanism 133, and the upper cover 127 is By removing the locking mechanism after opening, it rotates counterclockwise around the shaft 132,
The transfer paper path after the register rollers 41 and 42 is opened, and the jammed transfer paper can be easily removed by hand. At this time, the separation belt 32 is separated from the photosensitive drum 15, and it is easy to remove the jammed transfer paper from the separation section.

After removing the jammed transfer paper, a jam release operation is performed and the upper cover 127 is closed, thereby returning the entire machine to its original state. Even if an attempt is made to close the upper cover 127 without carrying out the jam release operation, the upper cover will not close, the bar switch 134 (FIGS. 6 and 7) will not operate, and the machine will not come into operation. Further safety is ensured by performing the confirmation operation as described above. Next, cassette 6
The mounting method on the main body will be described with reference to FIG.

The foot part 145 of the cassette 6 is placed on a cassette holder 144 fixed to the machine body, and when the cassette is pushed into the machine body, a spring 149 having a roller 148 is used so that the protrusion 146 at the bottom of the cassette hits the positioning plate 147 of the cassette holder. The cassette 6 is pressed into a predetermined position.

At this time, a cam 150 provided on the cassette side wall and a microswitch 151°15 installed on the cassette stand 144
2, a cassette loading signal and a size switching signal are output. The document holding cover provided on the document table is attached with screw 135.
136 (Fig. 2) is fixed to the document table.
It can be easily removed if you want to copy a large three-dimensional object. The paper discharge tray 47 is located behind the paper discharge rollers 46, 45, and is provided slightly upwardly as shown in FIG. The paper discharge tray 47 has a hook portion 47a and a tray portion 47b.
is rotatably attached with a screw 140, and the tray portion 47b is rotated to an approximately vertical position and fixed. With the above configuration, the cassette 6 can be easily attached and detached without removing the entire paper discharge tray 47 from the machine body.

As shown in FIG. 3 (because the guide rail 70 is installed in a horizontal position, dirt and foreign matter will not accumulate on the runner part 70a (the document table 2 will always move smoothly). When the document table 2 is in a predetermined position, the guide rails 70 are all under the document table 2, which is effective from the standpoint of safety and dust prevention.

Next, first, a sequence control circuit using a digital IC,
In particular, the sequence control circuit related to the reciprocating movement of the document table will be explained.

(Counting means) Next, the clock pulse counter circuit is shown in FIG. 14(a).
The time charts are shown in Figure 14 (b) and Figure 14 (c).
This will be explained in . First, the circuit 221 is a clock pulse generator, which detects periodic changes in magnetic field strength using a magnetosensitive element, generates a pulse according to the output of the element, and uses it as a clock pulse. Fourth
161) is caused to periodically pass near a magnetic sensing element (FIG. 4, 71) that utilizes the Hall effect and is fixed at a specific position in synchronization with the rotation of the photosensitive drum (FIG. 1, 15). This generates a pulse-shaped output as the output. Further, the circuit 231 is a well-known binary counter that inputs clock pulses from 1 to 0 at the CP input terminal.
It is triggered when a falling signal is applied sequentially to output terminal A, output terminal A is output with the clock frequency divided by 1/2, output terminal B is output with frequency divided by 1/4, and output terminal C is output with frequency divided by 1/4. An output whose frequency is divided by /8 and an output whose frequency is divided by 1/16 are generated at the output terminal. That is, these outputs are shown in FIG. 14 (b
) 231' A, 231' B, 231' C.

231'D. However, in FIG. 14(b), 222' is a signal input from the output terminal 222 of the clock pulse generator 221 in FIG.
0 and thus the rising portion of signal 222' becomes the trigger point. Note that the clock pulse signal at the terminal 222 is hereinafter written as CLOCK. Furthermore, counter 2
When 1 is added to the CLEAR input terminal of 31, A,
The B, C, and D output terminals all become O, and the state at this time is exactly the same as when the 0th and 16th clock pulses are applied, as shown in FIG. 14(b). Also, unless 1 is added to the CLEAR terminal, the output state is O.
The states from the 15th to the 15th states are repeated, and in the following explanation, when 1 is added to the CLEAR terminal, and when the clock pulses corresponding to the 0th and 16th states are added, all 16
This state is called the state in which the th clock is added. Figure 14 (
In a), the CLEAR terminal of the counter 231 has
Three types of reset signals are applied to effectively activate other circuits: First, r mouth sweat is applied from the terminal 208 to one input terminal of the three-man power NAND gate 225 as a reset signal when the power is turned on, and a signal CBBP (
An inverted signal ff (details will be described later) is applied from the terminal 223 to another input terminal of the gate 225. gate 2
A pulse signal indicating the end of post-rotation is applied to the other input terminal of 25, and this can be generated as follows. First, an inverted signal LRT of the signal UTT (details will be described later) indicating that the rear rotation is in progress is applied from the terminal 224 directly to one input terminal of the two-man power AND gate 242.
Furthermore, it is applied to the input terminal of the pond via inverters 227, 228, and 229. At this time, as shown in FIG. 14(c), the signal 224' at the terminal 224 and the output 229' of the inverter 229 are in an inverse relationship;
Since the signal 229' passes through three inverters with respect to the signal 224', there is a delay in the signal.

If this delay time is TD, then the output signal of the gate 242, 242', is the TD time 1 from the falling edge of LRT, that is, the rising edge of the signal 224' to the falling edge of the signal 229', as shown in the figure. becomes. Thereafter, a signal indicating the end of rotation (hereinafter referred to as LRTEP) is output from the terminal 243 to other circuits and is further applied to the gate 225 via the inverter 226. Therefore, it becomes a reset signal. As shown in the figure, the output signal 225' of the gate 225 is output as 1 and resets (clears) the counter 231 when any one of 5TOP, CBBP, and LRTEP becomes 1. Next, the outputs of the counter 231 are further combined as follows. First, the two-man power A N D gate 235 has an inverter 2 with a C terminal output and a D terminal output.
A D terminal inverted output via 34 is applied to each input terminal;
In addition, the output of the gate 235 and the B terminal output are applied to each input terminal of the two-man power AND gate 236, and the C terminal output of the B terminal output and the C terminal output is applied to the three-input AND gate 237 via the inverter 233. A terminal inverted output and a D terminal output are applied to each input terminal, and a three-input AND gate 238 has B and C terminals.

Each terminal output of D is connected to an inverter 232, 233.
An inverted output via .degree. 234 is applied to each input terminal. Therefore, the output 239' of each AND gate 235
is the period 1 of the 4th to 7th clock pulse,
The output 240' of the gate 236 is the period l of the 6th to 7th clock pulse, and the output 240' of the gate 237 is
1' is the period l of the 10th to 11th clock pulse, and the output 211' of the gate 238 is
The period 1 is from the 16th (0th) to the 1st clock pulse, and the terminals 239 . 240. 241°211, output as 4CP, 60P, 10CP, and 16CP signals. In this embodiment, 15.75 clock pulses are generated per rotation of the drum.

This is true in the 16-bit power count method mentioned above.
Counting 16 clock pulses effectively indicates that the drum has completed approximately one revolution.

(Pre-exposure strong illuminance lighting circuit) Next, a pre-exposure strong illuminance lighting command signal BRIGHT (hereinafter simply referred to as BRIGHT) generation circuit is shown in FIG.

As described above, in order to improve the efficiency of the copying process in this embodiment, the following photosensitive drum (hereinafter simply referred to as drum) rotation sequence is set up.

In this copying machine, after the power is turned on and each circuit is reset by the WUP: signal, the drum first rotates as a forward rotation, and if the copy button is not pressed at this time, the drum stops rotating and is in a rest state. to go into. In this pause state, when the copy button is pressed and CCM D becomes 1, the fluorescent 4 to wait for the delay in lighting time of the lights.
After waiting for the clock, the advance of the document table is started, and when forming the latent image of this -th copy, the primary charger (Fig. 1 21) is started.
), the drum is exposed to light to correct differences in the state of the drum photosensitive layer during continuous copying. However, this exposure (hereinafter referred to as pre-exposure) remains dark even when copying the second and subsequent sheets, but the circuit shown in Figure 20 uses BHIG as a signal to turn on the pre-exposure strongly when copying the first sheet.
This is a circuit that generates an HT signal. First, CCM D is 1
, and the state where CEXC is 0 means that the CEXC generation circuit (first
As described in Figure 9), it appears only immediately before the -th copy is executed.

The CCMD signal is applied from terminal 271 to one input terminal of the two-man NAND gate 293, and the CEXC
is connected to the gate 29 from the terminal 283 via the inverter 289.
3 to the other input terminal. Therefore, this CEXC
When is O and CCMD is 1, the output of gate 293 becomes O, which is added to the ≦ terminal of FF295, and FF2
The output Q of 95 becomes 1, and from the terminal 298 BRIG) (
It is output as a T signal. The pre-exposure illuminance, which has become strong when the BHIGHT signal becomes 1, must be returned to weak illumination after the drum has rotated approximately once in order to achieve the above-mentioned purpose. For this reason, I made an A4 size copy.

For B4 size copying, the signal A4BP indicates that the document glass has reached the A4 size inversion position (details will be described later).
becomes 1, and in the case of B5 size copying, the document table does not reach the A4 size inversion position, so the document table reaches the B5 size inversion position and moves to the first position as described above.
Figure 4 (a) The counter 231 is reset and then rises when the fourth clock pulse is input.
When the 0P signal is issued, the FF 295 is reset to stop the high intensity irradiation of the pre-exposure.

In the circuit, the A4BP signal is first applied from the terminal 287 to the R terminal of the FF 295 via the inverter 291 and the three-input A N D gate 297. Therefore, when A48P becomes 1, O is added to the R terminal, the FF 259 is reset, and the output Q becomes O. Also, A4BP is not 1,
When the 4CP signal rises, this signal is transferred from the terminal 288 to FF2.
In addition to the CP terminal of the FF 95, the D terminal is connected to GND (earth), so the output Q of the FF 295 becomes O. Here, as a signal for resetting the FF 295, CEXC is inverted and applied from 5TOP and the terminal 283 to one input terminal of the two-man NAND gate 294 via the inverter 289, and the other input terminal is supplied to the terminal 2.
CCMD is applied from 71 via inverter 292. The outputs of the gates 294 are applied to the R terminal of the FF 295 via gates 297, respectively. This is because 5TOP, which is a reset signal when the power is turned on, resets FF295, and CCMD is 1 and CEXC is O, which sets FF295 (output Q
1), if CCM D becomes O before CEXC rises even after 4CP rises and CBFOR rises, the document table will not move and copying will not be performed. CEXC is set to O, CCMD is set to O, and the output of the gate 294 is reset so that the exposure is returned to weak light. Here, the 4CP signal is applied to the CP terminal to reset the FF 295 during B5 size copying, but even if the 4CP signal rises after CCM D becomes 1, the document platen advance command signal CBFOR will not be activated as described later.
becomes 1 with the rise of 4CP, and CEXC rises with the rise of CBFOR. Therefore, CEXC remains O when 40P rises, and at this time, the FF 295 is not reset by the rise of 4CP.

(Rear rotation command circuit) Next, the rear rotation command signal LRT generation circuit is shown in FIG. 16(a).

The time chart is shown in FIG. 16(b) and will be explained.

In this embodiment, the post-rotation is performed after the latent image formed and developed on the photosensitive drum in the last copying machine is transferred to the transfer paper, and ends after the drum has rotated approximately once.

First, the FF 305 is reset when the power is turned on by the 5TOP signal applied from the terminal 208 to the terminal via the two-way AND gate 304, and the Q outputs are respectively 0. It becomes 1. Next, the tocp signal is applied to the terminal 241 Kara F F 300 (7) CP triple, but
This signal becomes 1 during the previous rotation, while the document table is moving forward, and at the time when the transfer ends after the document table reaches the reversal position and the counter 231 in FIG. 14(a) is reset. Occur. Therefore, to the D terminal of the FF 305, first, CEXC is applied from the terminal 283 to one input terminal of the three-input AND gate 3030, and the inverted signal of CBFOR is applied from the terminal 276 to the other input terminal via the inverter 301. By adding output enable to another input terminal and adding the output of its gate 303, FF3
05 is set and the Q output becomes 1 when CEXC is 1.
, and only when CBFOR is O and LRT is 0, F
The state becomes such that F305 can be set. However, terminal 271
CCM from the gate 304 to the R terminal of the FF 305
Since D is added in reverse, FF305 is actually set when CCMD is exhausted and becomes 0 (when the copy button is turned off), that is, when the last copy is being made. . This also means that when FFR305 is set and LRT becomes 1 and the copy button is pressed while performing post-rotation, CCMD becomes 1.
At that point, the backward rotation is stopped and the vehicle starts moving forward. 4
It resumes forward movement without requiring a clock.

Also, as mentioned in the explanation of FIG. 14(a), the reason why l0CP rises again after the 100P signal rises to 1 is because
This occurs when 16 clock pulses are generated.

Therefore, during this time, the drum rotates approximately once, and at this time, the output port of FF 305 applied to gate 303 is 0, and the D terminal is O, so the output Q of FF 305 is reset to O. The rotation ends.

Note that the outputs Q and ζ of the FF 305 are outputted from terminals 306 and 224 to other circuits as LRT and output, respectively.

A time chart is shown in FIG. 16(b). signal 208'
.

271', 276', 283', 241'
, 306' are terminals 208.271.2, respectively.
The signal waveform at 76.283.241.306 is 2
After continuous copying of 10. The CP signal rises and the LRT rises, but the illustration is based on an example in which one copy is performed again after rotation.

(Original table reciprocating circuit) Next, a document table forward and backward command signal generation circuit is shown in FIG. 17 and will be described. First, to explain the document table movement sequence, forward rotation is performed after the power is turned on, but after the end of forward rotation (although CEXC is still 0 at this time), CCMD
When becomes 1, the document table waits for 4 clock pulses and then starts moving forward. With these four clocks, it is possible to form an image while avoiding the portion of the first drum facing the cleaner. B5. A4
．． When each reversal position of B4 is reached, retraction is started and the document table returns to the home position (starting position). However, in this embodiment, if the document table is not at the home position, the document table cannot be started, but when the power is turned on, it automatically moves to the home position.

In this embodiment, a pair of a magnet and a Hall element is used as the position detecting device for the document table, similar to the clock pulse generator shown in FIG. 14(a).

That is, a magnet is attached to the document table, and a Hall element fixed to the main body detects changes in the magnetic field strength due to the movement of the magnet, so that the document table is moved to the home position B.
5. A signal indicating that the reversal position has been reached in each copy size of A4 and B4 is generated. 17th
In the circuit shown in the figure, a signal CBHP (hereinafter CBH
P and write() are applied to one input terminal of the two-man power AND gate 315, and CCMD is applied from terminal 271 to the other input terminal. Therefore, if CCM D becomes 1 when the document table is at the home position, the output of the gate 315 becomes 1 and is applied to the D terminal of the FF 324.

Also, since the CLCK signal is applied from the terminal 222 to one input terminal of the two-man NAND gate 316, and the CEXC signal is applied from the terminal 283 to the other input terminal, the CEXC signal is applied from the terminal 283 to the other input terminal.
When EXC is 1, the gate 316 outputs an inverted signal of CLCK. In addition, two-man power N A N D gate 31
9, the 4CP signal from the terminal 288 is applied to one input terminal, and the CEXC is applied to the inverter 31 to the other input terminal.
8, so when CEXC is O, gate 3
19 outputs an inverted signal of 4CP. The outputs of these gates 316 and 319 are further connected to a three-input NAND gate 31.
7 input terminal, and the gate 317 further has FF3.
24 ζ outputs are applied to the input terminals. Therefore FF32
When the ζ output of 4 is 1, the CLCK or 4CP signal is outputted from the gate 317 via the gates 316 and 319, respectively, and applied to the CP terminal of the FF 324. Therefore, when copying the -th sheet, that is, when CEXC is 0, CC
When MD and CBHP become 1, the FF324 is set at the rising edge of the 4CP signal, the output Q becomes 1, and the terminal 27
6 to document platen advance command CBFOR (hereinafter simply CBFOR)
is output as (). Therefore, even after the pre-rotation of 4CP, the conditions for advancing are that the copy command is received and the document table is at the home position, and therefore, the displacement of the document table during the pre-rotation can be monitored, so that accurate image formation is possible.

In addition, for the second and subsequent copies, CEX has already been used at this time.
Since C is 1, when the document table returns to the home position and CBHP becomes 1, the next input CLCK
When the signal rises, CBFOR becomes 1 and the document table moves forward. Therefore, since forward movement is not immediately resumed only by detecting the home position, smooth forward movement can be started. In addition, the advantage of the endless photoreceptor, which can be restarted from any drum surface, is not lost. In addition, since the start of advance for the first and second sheets is controlled using different methods, the advantage of being able to evenly expose the image at any position on the drum surface is not lost, and the pre-rotation time until the start of forward movement for the first sheet is reduced. Coupled with the fact that it is not added to the second and subsequent copies, the time required for repeated copying can be extremely shortened. Next, to reverse the document table, the output of the three-input AND gate 322 is a two-person AND operation.
This is done by applying it to the R terminal of the FF 324 via the gate 323. In other words, in the case of B5 size copying, the B5C signal is set to 1, and the two-man power N A is output from the terminal 257.
is added to one input terminal of the N D gate 320, and the 8
5BP is applied from terminal 312 to the other input terminal. Therefore, at this time, when B5BP becomes 1, the gate 320
, 322 and 323, and is applied to the terminal of the FF 324, thereby resetting the FF 324. In the case of A4 size copying, the A4C and A48P signals input from the terminals 258 and 287 are applied to each input terminal of the two-man NAND gate 321 in exactly the same way, and the output is further sent to the gate 3.
22 to one input terminal. In the case of B4 size, B4BP is inverted from the terminal 313 via the inverter 327 and applied to another input terminal of the gate 322. Therefore, each document table reversal signal is inverted via gates 322 and 323 and applied to the terminal of FF 324, and at this time, the output ζ becomes 1, and the two-man AND
The document table backward movement command signal CBREV is sent via the gate 325.
(Hereinafter, it is simply written as CBREV () and is output from the terminal 326 to the Ike circuit. However, when the document table returns to the home position at the gate 325 and CBHP becomes 1, 0 is output to one input terminal via the inverter 314. As a result, CBREV becomes O and backward movement stops.If the document table is not at the home position when the power is turned on, it will automatically move to that position via the gate 32 through the inverter 3 and 4.
Output added to 5? ffTn' and reset FF1
This is because, in combination with this output of 24, CBREV becomes 1. Therefore, it is possible to automatically move to the home position until just before the forward movement starts. Note that 5TOP is also applied from the terminal 208 to the R terminal of the FF 324 via the gate 323, similarly to other circuits.

Therefore, when an abnormality is detected in the charger, forward movement is stopped and the movement is switched to reverse, so that no defective images are produced unnecessarily.

Further, the output of the gate 322 is an inverted signal of the document table reversal position signal, and is outputted as rn level from the terminal 223 to other circuits. FIG. 17(b) is a time chart when CCMD and CEXC are 1 in the circuit shown in FIG. 17(a), and 311', 222', 322'
.

The signal waveforms shown at 276' and 326' are CBHP.

Corresponds to CLCK, ff, CBFOR, and CBREV.

(Paper feed circuit) Next, paper feed start command signal PFSD (hereinafter simply PFS
(written as D) generation circuit is shown in FIG. In the figure, from the terminal 331, a signal indicating that the document table has reached a specific position is sent by a magnet 161 and an element 71 using means similar to the document table reversal position detection means shown in FIG. 17(a). This is input as the paper feed timing signal PF'SP and applied to one input terminal of the two-man power AND gate 332. Since CBFOR is applied from the terminal 276 to the other input terminal of the gate 332, the document table is When the PFSP is input as 1 during forward movement, the gate 332
The output becomes 1 and is output from the terminal 336 as PFSD. Further, in this embodiment, the PFSD signal and each copy size signal are added to each input terminal of a two-man AND circuit, and the output thereof is used as a count signal for the number of copies.

That is, in FIG. 18, B5C, A4C, and B4C are input from terminals 259 and 258.257, respectively, and two-person power A
In addition to one input terminal of ND gate 333.334.335, the output of each gate is B5C0UNT from terminal 337.338.339.

A 4 COUN T, B 4 COUN N
Output as T. As described above, in the present invention, in which the movement accuracy and position detection accuracy of the document table are high, it is possible to reproduce an image that is faithful to the original even as a copy image.

〔Effect of the invention〕

As described above, according to the present invention, even if there is an assembly error, deflection of the document table can be prevented, image deterioration such as distortion of the document image does not occur, and the position of the document table can be accurately detected, so that the document table can be moved. Accuracy can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a copying apparatus according to an embodiment of the present invention, FIG. 2 is an external perspective view thereof, FIG. 3 is a vertical cross-sectional side view of FIG. 1, and FIG.
5 are sectional views and perspective views showing the driving relationship of the copying device, FIGS. 6 and 7 are partial sectional views showing the operation of the safety device, FIG. 8 is a perspective view showing the fixing device, and FIG. 9 is a partial sectional view showing the operation of the safety device. The figure is a sectional view showing the paper feeder drive section, FIG. 10 is a perspective view showing the document table drive section, FIG. 11 is a perspective view showing the cassette, FIG.
3 is a sectional view showing the document table stop device, FIG. 14(a) is a clock pulse counter circuit, FIG. 14(b) is its time chart, FIG. 14(c) is a waveform diagram for clearing the counter, and FIG. Figure 15 shows the pre-exposure strong illuminance lighting command signal generation circuit, Figure 16 (a) shows the rear rotation command signal generation circuit, Figure 16 (b) shows its time chart, and Figure 17 (a) shows the document table, forward movement, FIG. 17(b) is a time chart of the backward command signal generation circuit, and FIG. 18 is a diagram showing the paper feed start command signal generation circuit. In the figure, 2 is a document table, 5 is a document table glass, 15 is a photosensitive drum, 48A, 48B, 48C, 71, 72 are magnetic sensing elements, and 161, 162 are magnets.

Claims (1)

[Claims] (1) In a document table moving mechanism of an apparatus that has a document table on which a document is placed and moves back and forth, and a main body to which this document table is attached and which houses an illumination means for illuminating the document, A first guide means for regulating the vertical and front-back directions of the manuscript table for guiding the movement of one end side, and a second guide means for regulating only the vertical direction of the manuscript table for guiding the movement of the other end side of the manuscript table. a driving means for driving the document table on the side of the first guide means, and a first guide means for detecting the position of the document table.
A document table moving mechanism comprising: a detection means provided on the guide means side; and a control means for controlling driving of the document table by the drive means based on a detection result from the detection means.