JPS6213662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying machine having a jam detection device.

Conventionally, it is known to control a copying sequence by counting a series of pulses generated by the rotation of a rotating body.

In this case, pulse counting is started by detecting a mark provided on a rotating body or by detecting the rotational position of a transfer roller or a registration finger.

Therefore, each detection signal may be generated repeatedly during execution of one copying cycle, and therefore, an output is generated by counting many times. Therefore, in order to control the operation at the optimal time, a circuit that selects the output is required. was needed.

In particular, the jam detection timing may be near the end of one copying cycle or may be delayed to the next cycle, requiring an extremely complicated selection circuit.

Also, there is a system that detects jams in relation to the timing of detecting the position of the scanning system, but the paper does not reach the jam detection location during the first scanning period, and the first jam is detected for the first time during the second scanning period. There are cases,
Therefore, there was a problem in that jams could not be detected when only one copy was made. However, in order to detect a jam on the first sheet, it was necessary to provide a timer that counts for a long time from the start of copying.

It is an object of the present invention to eliminate the above-mentioned drawbacks, namely, to provide a reciprocating member for exposing and scanning a document in a copying apparatus that exposes a photoreceptor to an image and transfers the exposed image to a copy material. (Fig. 1 2), means for detecting the size of the copy material storage section (Fig. 11 15)
1,152 (Fig. 17), a copy material detection means provided in the copy material path (Fig. 1 129, 130), a memory for outputting a jam signal (Fig. 24a, 346), means for generating a pulse (FIG. 4 163, 164), means for varying the reciprocating distance of the reciprocating member according to the size detected by the size detecting means (22nd
(Fig. 23), a means (23rd figure) for starting feeding the copying material towards the copying material passage in synchronization with the movement of the reciprocating member.
(Fig. 16a), a counting means (Fig. 16a) that starts counting a predetermined number of pulses based on the inverted position of the reciprocating member, and a copy material reaches the copy material detection means when the counting means finishes counting the predetermined number of pulses. control means for setting the memory and outputting a jam signal by using the predetermined number of count signals from the counting means (FIGS. 24a and 24b);
The copying apparatus is characterized in that the number counted by the counting means after the reciprocating member completes forward movement is changed depending on the size of the copying material. As a result, in a device that detects delay jams by counting pulses from the reversing position of the reciprocating member, it is possible to detect delay jams with accurate timing for copying materials of various sizes.

(Summary) The apparatus of this embodiment uses an endless photoreceptor and uses 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 indispensable, and in addition, regarding the control of the copying cycle, it is necessary to change the home position of the drum for each rotation of the photosensitive drum, as in the case of conventional edged photosensitive drums. Controlling the installation cycle is extremely wasteful. For this reason, this apparatus employs a drum having an endless photoreceptor, and also has a pulse generator at regular intervals corresponding to the rotation of the photoreceptor drum from the photoreceptor drum drive device, and generates pulses at regular intervals corresponding to the rotation of the photoreceptor drum. Each cycle is controlled by a counter device. For example, the clock pulse generator described above is configured to generate 15.75 pulses per rotation of the drum. By doing this, the drum can make one complete revolution and slightly overturn when the counter counts 16 clock pulses. This eliminates the unprocessed portion of the photoreceptor before and after the copying cycle in the pre- or post-processing steps described below, and therefore allows the copying process to be started from any part of the photoreceptor, which is an advantage of the endless drum. make it possible.

(Pre-treatment) 1. 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 become the same between the first sheet and subsequent copies due to the fatigue effect of the photoreceptor.

2 Furthermore, as described below, if the copy is left unattended after copying,
Toner may adhere to the contact area between the cleaning blade and the photoreceptor, which may require cleaning prior to the copying cycle.

(Post-processing) Since the photoreceptor is charged at high voltage with various potentials, the surface potential and polarity of each part of the photoreceptor are different. If left in this state, the characteristics of the drum will be adversely affected, so the copy cycle At the end of the process, it is desirable to remove static electricity from the surface using, for example, AC corona.

Furthermore, if the drum is stopped at a fixed home position, such as with a conventional edged photoreceptor, the stopping position is always constant, so the effects of corona charging will accumulate in the same part, and the drum Since the cleaner is pressed against the drum with considerable pressure, it is inevitable that the same portion of the photoreceptor will undergo physical deformation. However, by generating an appropriate clock pulse per rotation of the drum,
It is possible to avoid the above-mentioned cumulative effect of the stop position and start position of the drum changing from moment to moment, and it is also possible to use the drum evenly over the entire length of the photoreceptor, contributing to a longer life of the photoreceptor. In addition, the copying cycle is not controlled by rotating the drum or by controlling means related to this as in the past.
This is done using a reversal signal from the document table or optical system that corresponds to the copy size as a reference, and a combination of this, a clock pulse, and a counter.The clock pulse counter can also be reset when the document table or optical system's reversal signal or post-rotation is completed. We aim to improve reliability by using a digital circuit with an effective circuit method such as a clock count (by switching the clock count according to the copy size as necessary) and a clock count at the exit of the fuser. An extremely simple and effective circuit is used as a jam detection means for monitoring delayed accumulation of copy paper based on the signal from the provided copy paper detector.

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.

Furthermore, in place of the micro-switch that is often used in conventional devices of this type, a non-contact type position detection device using a magnetic detection element is often used. These are the liquid level detector, clock pulse generator, copy command button, original platen home position, paper feed start timing signal generation position, B5 size inversion position, and A4
All of the position detection devices used for the size reversal position and B4 size reversal position are equipped with a magnet in a movable part, and the change in magnetic flux density due to the movement of the magnet is detected at a specific position by the effect of the Hall effect or the change in resistance of the semiconductor due to magnetism. By using this in a detection device using this, the following effects can be obtained. First of all, compared to position detection devices using contact type elements such as micro switches, reed relays, contact type elements, or pairs of light emitting elements that use light as a medium, there are no contact failures, rough installation accuracy, or toner etc. By having advantages against contamination, reliability can be improved and lifespan can be extended. Furthermore, as will be described later, in this embodiment, since a digital IC is applied to the control circuit, one of the advantages is that the above-mentioned device, which serves as a source for generating various signals, does not cause the rotary phenomenon. This circuit also uses a digital IC to make it smaller and more reliable than conventional relay-based control circuits, as well as to increase its flexibility for complex sequences. Furthermore, the switching elements for energizing each terminal element in accordance with control signals have been changed from conventional relay-based switching elements.
Reliability is improved by using semiconductor switching elements such as thyristors and transistors. As is well known, digital ICs are used for relays.
or semiconductor switching elements, relay contacts may be defective,
The effect of being freed from the drawbacks of large size and high cost is significant. 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. can be solved, and a more reliable copying machine control circuit can be constructed.

(Explanation of Operation of Apparatus) 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 fully utilize the features of this machine as will be described later.

First, when the main switch 10 is turned on, a very short time (approximately 1 second in this case) has elapsed due to the controller being reset and other electrical systems starting up due to the use of a digital circuit. 15 starts rotating. As mentioned above, this is approximately 16 times per rotation of the photosensitive drum.
A clock pulse generation mechanism is provided in a part of the drive system so as to generate clock pulses of 100 times. When the photosensitive drum 15 begins to rotate, the drum rotates approximately once for 16 clock pulses (hereinafter referred to as 16CPetc). This can be considered a step before starting the copying process, and is intended to obtain a high-quality copy when the copying process begins, and may be omitted in some cases. Here, if the copy button 13 is not turned on, the photosensitive drum will continue to rotate once and then stop; however, if the copy button 13 is turned on, the copying process will begin immediately. First, the photosensitive drum 15 rotates by 4 CP in addition to 16 CP when the copy button is turned on, and only then does the document platen glass 5 rotate.
The document table 2 with the document placed on it starts, is illuminated by the illumination lamp 16, and its image is reflected on the reflection mirror 1.
7. An image is formed on the drum 15 by the exposure section 19 using the 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 + by a corona current from a positive charger 21 supplied with a high voltage of + 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 exposed to the photosensitive drum 1, as described above.
5 is slit exposed. At the same time, AC high voltage is being supplied from the high voltage power supply 20. AC charging is performed by an AC 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, one end of which is grounded. The developing electrode 28 is always kept at a constant distance from 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 from the high voltage power source 20, 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 section is transferred to the photosensitive drum 15.
The image on the photosensitive drum 15 is transferred onto the transfer 7 by an electric field generated by a + high voltage from the power source 20 by the transfer charger 31. After the transfer, the transfer paper 7 is separated by a separation belt 32 and guided to a drying and fixing section 33. The remaining toner developer on the photosensitive drum 15 is wiped off by the edge portion 35 of the blade cleaner 34 that is pressed against it, and the next cycle is repeated again. The developer wiped by the blade cleaner 34 is guided to the developing device 24 through grooves 36 provided at both ends of the photosensitive drum 15 (FIG. 3) and used again for development.

Here, the main switch 10 mentioned earlier is turned on, and the drum rotates by an amount equivalent to 16 CP.
To explain why the document table 2 starts moving only after the drum has rotated by +4CP, this machine uses an endless type photosensitive drum, and therefore, no surface of the photosensitive drum can be used for image formation. I am now able to contribute. Therefore, if you want to increase the number of copies per unit time by eliminating unnecessary rotations as much as possible, first of all, if any toner remains in the blade cleaner edge portion 35 for the first rotation of the drum,
In the worst case scenario, if this machine is not used for one cycle or 10 days, it may dry out and become stuck to the drum, in which case it is necessary to clean the photosensitive drum before forming a latent image. It is.

Next is 4CP, which is because in the copying process mentioned earlier, there is a + charging process etc. before the slit exposure, and in addition, the cleaner edge part mentioned above is added to the first sheet. This process is based on the idea that avoiding this when copying will make the machine more reliable.

Next, the transfer paper 7 is stored 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 as the spring 38 pushes up the middle plate 37, the transfer paper 7 is always pressed against separation claws 39 provided on both sides of the tip of the cassette 6. ing. By appropriately selecting the spring constant of the removing 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 document table reaches a predetermined position, an operating piece fixed to the document table activates the detection means on the main body side and a signal is output, and the constantly rotating paper feed roller 40 descends and feeds the paper into the cassette 6. The transfer paper contacts the topmost transfer paper, and moves with the separation claw 39 to separate one copy of the transfer paper and send it out from the cassette 6. However, the nearby register rollers 41 and 42 stop at the same time as the paper feed roller 40 descends, so the cassette 6
The transfer paper 7 fed out from the transfer paper 7 creates a slack between the guides 43 and 44 with its leading edge touching the contact portions of the register rollers 41 and 42. Then, when the paper feed roller is about to rise, the register roller 4 is moved again at the leading edge of the image on the photosensitive drum.
1 and 42 rotate, and the transfer paper 7 is sent at a speed that matches the circumferential speed of the photosensitive drum 15.

As mentioned above, the transfer paper 7 is attached to the photosensitive drum 1.
5, 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, passes through the dry fixing section 30, and is transferred. The toner on the paper 7 is fixed and discharged onto a discharge tray 47 by discharge rollers 45 and 46.

Next, the operation for copying will be explained with reference to FIGS. 2 and 3. Place the document to be copied on the platen glass 5 with its leading edge aligned with the leading edge A of the glass, press it with the cover 3 (Fig. 2), and press the copy button 13 (Fig. 2). starts rotating and at the same time starts operating. 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 the slit to perform slit exposure. When the exposure is completed, the document table 2 stops moving to the left and immediately returns to the opposite direction, that is, to the right, in response to a signal from the document table 2 itself according to the size of the paper in the cassette. 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.
In this machine, which is prone to shock when stopping due to its fast return speed, the brake mechanism, which will be described later, absorbs the shock and quickly stops the document table 2 at a predetermined position. Even when a large number of copies are to be made continuously from the same document, this can be easily done by using a counting device (not shown) that is linked to the copy button 13. The counting device detects the movement of the original platen 2, performs counting, and holds the switch element until the set number of sheets has been counted, so that a large number of copies can be made.

The original platen restart command during continuous copying is sent to the original platen 2.
1CP after stops at the predetermined home position
It is carried out by. This is to ensure that the document table 2 moves smoothly 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, if the document table 2 were to move a distance of B4, which is the maximum copy size, for any copy size, the number of copies per unit time would be small, resulting in a large time loss. Therefore, this copier supports various copy sizes (for example,
(corresponds to A4, B5), document table reversal signal generation member 48
(Fig. 4), and the copying cycle is changed according to each copying size to improve copying efficiency.

The above-mentioned differences in cycles depending on the copy size are determined by signals from the cassettes 6 for each size.

Next, the suspension state and restart after copying is completed will be described. If the power is left on after all copying operations have been completed, the photosensitive drum 15 will constantly rotate, and if the high-voltage power is on, this is not desirable in terms of the durability of the photosensitive drum 15 and the blade cleaner 34. Therefore, in the copying machine of this embodiment, when a certain copying operation is completed and the next copying operation is not performed even after a certain period of time has passed, the main switch 10 is turned off.
Even if it is ON, the drum will automatically stop and go into hibernation mode. 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 perform copying during this pause state, press the copy button 13 of the operation unit 9, and everything will return to the state before the pause, and after 4CP, the document table 2 will start moving 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.

In FIG. 3, reference numerals 49 and 50 are 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.
A drum shaft 53 is fixed to.

As shown in FIG. 3, the drum shaft fixing member 52 is fixed to the rear frame 50 with a large interval, so that it has sufficient strength against the weight and other forces of the drum 15 even in a substantially cantilevered state. It is composed of A drum gear 56 is rotatably supported on the drum shaft 53 via bearings 54 and 55.
A bearing pusher fitting 57 is fixed to the drum shaft 53 with a set screw, and is held down 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. Support plate 58
includes a thrust holding member 59 movable in the thrust direction.
, the bearing 61 held on the drum by the spring 60 is pushed to the left in FIG.
5 so that there is no play in the thrust direction. The photosensitive drum includes a drum 62, a front flange 63, a rear flange 64, a guide pipe 65, and two rods 6.
6. Bearing 6 press-fitted into front and rear flanges 63, 64
1,67, and the drum 62 is connected to the front and rear flanges 6.
It is assembled by scissors 3 and 64 and tightening with rod 66. The guide pipe 65 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. By supporting the drum quasi-cantilevered as described above, the drum is compactly constructed and easily assembled and disassembled while providing sufficient strength. By fixing the drum shaft 53 to the machine body and configuring it with a hollow pipe, a heating element 69 is installed inside the drum shaft 53 to keep the photoreceptor at a constant temperature, thereby preventing moisture from condensing on the drum surface at times of high humidity. Furthermore, it is possible to obtain high-quality images in a low-temperature environment.

A guide rail 70 is provided at the upper end of the rear frame 50.
and control signal magnetic sensing elements 48A, 48B, 4
Members 73 and 74 for attaching 8C, 71 and 72 are fixed (FIGS. 3 and 4). Further, guide rollers 75 and 76 as shown in FIG. 3 are installed at the upper end of the front frame 49, and cooperate with the guide rail 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 body,
It has sufficient rigidity to withstand various forces such as forward movement, backward movement, and reversal. Transparent glass 5 in the center of the frame,
When copying a book, etc., other pages of the book are placed on the front of the frame (the left end in Figure 1), and the entire page to be copied is placed in good contact with the glass surface (4). The document table 2 is constructed by the following.

The rear guardrail 70 is a lower rail 79 fixed to the rear frame 50 via mounting members 73 and 74.
The upper rail 81 is fixed to the rear angle 77 of the document table, and the retainer has a metal ball 80 which is positioned between the upper and lower rails and is rotatably held. and the position in the front-rear direction (left and right in FIG. 3). Further, the reciprocating movement of the document table is controlled by the metal ball 80.
Guided by rolling. On the other hand, the protruding tray portion 3 of the document platen front angle 78 is connected to the lower guide roller 7.
6 and upper guide roller 75, the vertical position of the document table is regulated. The guide rollers 75 and 76 are rotatably held by shafts 82 and 83, and the shafts 82 and 83 are fixed to a mounting plate 84,
It is firmly held by the front frame 49.

As mentioned above, the rear guide rail 70 regulates the vertical and front-back (left-right in FIG. 3) position, and the guide rollers 75 and 76 regulate the front angle of the document platen only in the vertical direction. As a result, the reciprocating movement of the document table is performed very smoothly regardless of manufacturing errors or assembly errors of the machine.

Magnetic detection elements 48 _A , 71, 72, 48 _B , 48 _C are fixed to the guide rail mounting bases 73 and 74, and magnets 16 attached to the document table 2
1,162 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. Furthermore, the document table moves forward and each copy size (B
5, A4, B4) is completed and the magnet 161 reaches above the element 48 _A , 48 _B , or 48 _C , 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.

The driving relationship will be explained with reference to FIGS. 5, 9, and 10. The main motor _M1 is driven by a sprocket wheel 85 through a chain 86, and a sprocket wheel 87 through which a gear 88 meshing with the aforementioned drum gear 56 at one end drives a fixed drum drive shaft 89. , chain 86 further drives a sprocket wheel 90 which is rotatably mounted on the shaft of an electromagnetic clutch 94. A rudder wheel 143 is fixed to the shaft of the electromagnetic clutch on the back side of 94. A rudder wheel 143 in FIG. 10 is connected to a rudder wheel 141 fixed to the output shaft of the clutch motor 95 by a rudder chain 142. A winding drum 91 is attached to the other end of the electromagnetic clutch shaft, and a document plate drive wire 92 is wound several times around the drum 91. Both ends of the wire are guided by guide pulleys 93, and the document plate drive wire 92 is guided by guide pulleys 93. It is fixed to the tip and rear end of the angle 77.

The above electromagnetic clutch 94 and clutch motor 95
By switching and driving the winding drum 91 in the forward and reverse directions, the document table 2 is reciprocated. A gear 96 is fixed to the drum drive shaft 89,
The drive of the main motor M ₁ is transmitted via a gear 97 to a gear 99 fixed to a paper feed roller drive shaft 98 . The main motor _M1 is driven by the gear 9.
One drives a gear 101 through a gear 100 which is integrally fixed with the clutch 9, and further drives register rollers 41 and 42 through a clutch 102.
Also, the gear 100 meshes with the gear 103,
A feed roller control cam 139 is driven via a clutch 137. The drum gear 56 (FIG. 3) is a gear 10 fixed to the separation shaft 104.
5 and the meshing separation roller 106 is driven.
A ladder wheel 10 is attached to the other end of the separation shaft 104.
7 is fixed, and discharge rollers 110 and 1 are connected via a ladder chain 108 and a ladder wheel 109.
11. A sprocket wheel ₁₁ is driven via a chain 86 from a sprocket wheel 85 attached to the main motor M1.
A gear 113 is integrally fixed to 2,
The gear 113 is connected to the clock pulse generating magnet 16.
The magnetic sensing element 16 is fixed to the rear frame 50 by engaging with the gear 115 fixed to the arm 114 holding the magnet 3 (FIG. 4) and rotating the magnet.
4 (Fig. 4) and the main motor _M1 by the magnet.
Generates clock pulses at regular intervals that are synchronized with the rotation speed of the motor. 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. At the same time as the paper feed roller 40 descends, the leading edge of the transfer paper hits the register rollers 41 and 42 which are stopped, forming a loop of the transfer paper between the guides 116 and 117 (FIG. 1). Then, the paper feed roller 40 rises, the register rollers 41 and 42 rotate 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 the embodiment, the copying efficiency is improved.
That is, in order to reduce the loss time during the backward movement, the speed of the backward movement is approximately four times that of the forward movement (approximately 200 mm/sec). In order to stop the document table, which moves at such a high speed, at a predetermined position on the machine body without applying a shock, this machine has a lock mechanism as shown in FIG. 12. The lock mechanism basically consists of a combination of a one-way clutch and a brake, and the solid line in FIG. 4 indicates the position of the lock lever on the document table and in the stopped state. Rear angle 77 that constitutes document table 2
A pin 155 fixed to the lock lever 153 engages with a notch 154 of the lock lever 153. Now, when the document table 2 starts to move forward (rightward in FIG.
, and rotates clockwise in FIG. 12.
At this time, since the one-way clutch 156 is in the releasing direction, the brake disc 157 remains stopped, and the brake disc 157 and the brake shoe 158,
The frictional force caused by 159 does not act as resistance to the movement of document table 2. When the document table further 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 the backward movement and starts the backward movement, heading toward the stop position at about four times the speed of the forward movement. Pin 155 is in lock lever notch 154
When the lock lever 153 is rotated counterclockwise from the dashed line position to the solid line position, the brake disc 157 is rotated counterclockwise via the one-way clutch 156. The brake disc 157 is sandwiched between brake shoes 158 and 159, and pressure is applied by a spring 160, and this frictional force absorbs the inertia of the document table without giving a large shock to the document table. It can be stopped. With this structure, there is almost no load on the document table when it starts, and sufficient braking can be applied when it stops.

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 supplied between the photosensitive drum 15 and the developing electrode 28 by a pump 27, and the latent image on the photosensitive drum 15 is developed with toner. become After development, fog is removed from the surface of the drum by a fog removing roller 29 disposed close to the drum surface. The fog removing roller 29 is rotated by a drive source (not shown) at a speed relative to the surface of the photosensitive plate, and the surface of the fog removing roller is constantly cleaned by a cleaning member 118. Scraper 11 located behind the fog removal roller 29
9 comes into pressure contact with the photoreceptor and removes the developer from the surface of the photosensitive 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. In FIGS. 4 and 8, a cross flow fan 120 is fixed to the rear frame 50, and a first absorption 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 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. An air outlet 126 of the cross flow fan 120 is guided onto the heating plate through an air duct 128 located above the hot plate 124 and fixed to the upper cover 127, and contributes to feeding and drying the transfer paper. As mentioned above, by performing suction and spraying with one fan, the device can be made smaller.
This method is effective in reducing costs, and by forming a semi-circulating system, the surface of the transfer paper is not covered with saturated steam, resulting in good drying.

Next, we will discuss the operation when paper feeding is defective. The copying machine of this embodiment has a jam detection means for checking whether the transfer paper has completed a predetermined process (feeding, transfer, separation, fixing) and has been ejected from the machine within a predetermined time. If the transfer paper stops due to an accident during the above process and is not ejected outside the machine after a predetermined period of time, the machine is stopped to prevent accidents such as fire. In FIG. 1, 129 is a light emitting element, 1
Reference numeral 30 denotes a light receiving element, which determines the presence or absence of a jam by counting a predetermined number of pulses from the clock pulse generation mechanism in response to a document table inversion command and detecting the presence or absence of a transfer sheet, the details of which will be described later. Therefore, since the pulse count for jam determination is started following the exposure scan, there is no need for a circuit to select the output, compared to the case where the count results are repeatedly output as the drum rotates. . When a jam is detected, the fuser heater is turned off and the main motor M is stopped, so the drum 15 is stopped, but the document table 2 is stopped after returning to a predetermined position (home position). When the machine is stopped, the upper cover 127, which can be opened about the hinge 131 in FIG. 1, is opened substantially vertically together with the duct 128. In this state, if there is nothing left on the hot plate 124 and a jam occurs in the fixing section, the upper cover 1
27, the transfer paper can be easily removed by hand. Next, the main body 122 of the transfer paper conveying section including the heating plate 124 is rotatably supported by a shaft 132 together with the separating section including the separating belt 32 and the like, and is normally held in a fixed position by a locking mechanism 133.
By opening 27 and then removing the lock mechanism, the paper rotates counterclockwise around the shaft 132, and the transfer paper path after the register rollers 41 and 42 is opened, allowing the transfer paper to be easily jammed by hand. Paper can be removed. At this time, the separation belt 32 is separated from the photosensitive drum 15, and it is easy to take out the transfer paper jammed in the separation section.

After removing the jammed transfer paper, the jam release operation is performed and the upper cover 127 is closed, thereby restoring 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 door switch 134 (FIGS. 6 and 7) will not work, and the machine will not come into operation. Further safety is ensured by performing the confirmation operation as described above. Next, a method of attaching the cassette 6 to the main body 1 will be described with reference to FIG. Cassette stand 14 fixed to the aircraft body
Place the feet 145 of cassette 6 on
The cassette 6 is pressed into a predetermined position by a spring 149 having a roller 148 such that the cassette 46 contacts the positioning plate 147 of the cassette stand. At this time, a cam 150 installed on the side wall of the cassette, a micro switch 151 installed on the cassette stand 144,
152 outputs a cassette loading signal and a size switching signal. The document holding cover provided on the document table is fixed to the document table with screws 135, 136 (FIG. 2), and can be easily removed when it is desired to copy a large three-dimensional object. The paper ejection tray 47 is located behind the paper ejection rollers 46 and 45 (slightly upward as shown in FIG. 2). 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, since the guide rail 70 is installed in a horizontal position, dust and foreign matter are not accumulated on the runner portion 70a, and the movement of the document table 2 is always smooth. Further, 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 viewpoint of safety and dustproofing.

Next, a sequence control circuit using a digital IC will be explained.

(Reset circuit) The circuit shown in Figure 14-a generates a signal (hereinafter referred to as STOP) that commands to stop the copying operation of the copying machine when the transfer paper is jammed or a spark discharge occurs in the charger, and to reset the entire circuit when the power is turned on. ), and Figure 14-b is its time chart. In FIG. 14-a, an inverted signal of a signal (hereinafter referred to as JAM) output when a jam occurs is applied from a terminal 201 to one input terminal of a three-input AND gate 207 from a transfer paper jam detection circuit to be described later. . However, here, for example, the signal "XYZ" is a signal at a level that is considered a high level signal or logic "1" if the event it means occurs, and is considered a low level signal or logic "0" if it does not occur. This means that it is a level signal, and below each level is simply written as 1 or 0. Also, it is a signal that has a level completely opposite to that of an inverted signal, and is expressed as XYZ. Also circuit 2
02 is 1 when spark discharge occurs in the charger.
Although the detailed explanation is omitted here, that signal will be expressed as DISCH below, and this
DISCH is input from terminal 203 and inverter 2
04 to the other input terminal of gate 207. Further, the circuit 205 is a circuit that generates a signal to reset the necessary parts of other digital circuits to the initial state before starting when the power is turned on, and outputs 0 for a certain period of time TR from the time of turning on the power, and when the certain period of time has elapsed. TR for a certain period of time in the circuit that outputs the second one
This is a timer circuit that is usually extremely short, does not require high accuracy, and can be easily designed by a person skilled in the art, so the details will be omitted. Hereinafter, this output will be expressed as WUP. This WUP is input from terminal 206 and applied to the other input terminal of gate 207. Therefore, as shown in Figure 14-b, if the input signals from terminals 201, 203, and 206 are respectively 201', 203', and 206', and the output of inverter 204, that is, the inverted signal of 203' is 204', then , the output of gate 207 is 202', 20 as shown as 208'.
If one or more of 4', 206' is 0, it becomes 0, that is, JAM becomes 1.
If DISCH becomes 1 or WUP becomes 0, it becomes 0 and is output from terminal 208, causing other necessary circuits to be reset. Therefore, by detecting a jam or an abnormality in the charger, the control circuit can quickly bring the charger into a stable non-operating state. still,
The reason for outputting an inverted signal of STOP as the reset signal is because it is convenient for the signal to be 0 when resetting in the following circuit.

(Pre-rotation circuit) Next, a circuit that generates a signal (hereinafter referred to as INTR) to perform pre-rotation when the power is turned on is installed in section 15-a.
As shown in the figure. First, the D-type edge-triggered flip-flop 214 will be explained. This flip-flop has a CP input terminal of 0.
When a rising pulse waveform moving from to 1 is added,
The same signal as the digital signal currently being applied to the input terminal D is output from the output terminal Q, until the next rising signal is applied to the CP terminal again.
The output state is maintained, but when 0 is added to the input terminal or 0 is added to the input terminal, regardless of the state of each input terminal of CP and D,
The Q output becomes 1 and 0 in each case and holds it. Further, the output terminal is a terminal that outputs an inverted signal of the Q output. A flip-flop with this function will be referred to as EF below. In the FF 214, first, the power supply voltage Vcc 213 is applied to the D terminal. Vcc is a level that is regarded as 1 as a digital signal in the circuit. Also, the terminal
STOP is applied from terminal 208. Therefore, since 0 is first added to the terminal for the time TR from when the power is turned on, 1 is output from the terminal and this state is maintained, but details will be described later. A signal 16CP from the clock pulse counter circuit indicating that the drum has made almost one revolution is sent to terminal 21.
1 is added to the CP terminal, and when this 16CP rises, the terminal becomes 0. The output of this terminal is further applied to one input terminal of a two-input NAND gate 215, and STOP is applied to the other input terminal. Therefore, the output of the gate 215 becomes 0 for the period when the terminal output 214' is 1 minus the period TR from the time of power-on, as shown in FIG. 216' of time chart No. 15-b. Output indicating to perform forward rotation
It is output from the terminal 216 as an inverted signal INTR of INTR. Therefore, during the reset period TR, INTR
Since no output is made, together with the initialization by the timer, the desired operation after the power is turned on does not feel abnormal. Also, when the charger is abnormal, STOP remains 0, so
INTR is not output even after TR. Therefore, since the main motor is only driven during normal operation, safety is improved.
High reliability. Note that since the rotation stop position due to INTR of 16CP is different from the initial position as described above, it is possible to prevent the accumulation of adverse effects on the drum due to the cleaning blade or charger. The reason for outputting the inverted signal here is that it is convenient for subsequent circuits. Further, in FIG. 15-b, 211' and 208' indicate signals input from the terminals 211 and 208, respectively.

(Counting means) Next, the clock pulse counter circuit is
Fig. 16-a and its time chart will be explained in Figs. 16-b and 16-c. First, the circuit 221 is a clock pulse generator, which detects periodic changes in magnetic field strength using a magnetosensitive element and generates a pulse according to the output of the element.
Specifically, in this embodiment, a magnet (161 in FIG. 4) is fixed at a specific position by synchronizing it with the rotation of the photosensitive drum (15 in FIG. 1). The magnet is caused to periodically pass through the vicinity of 71 in FIG. 4, and an output shaped into a pulse is generated as the output of the magneto-sensitive element. The circuit 231 is a well-known binary counter that is triggered when a falling signal from 1 to 0 is continuously applied to the CP input terminal as a clock pulse, and the output terminal A receives a 1/2 clock pulse.
An output with a frequency divided into 1/4 is generated at output terminal B, an output with a frequency divided into 1/8 is generated at output terminal C, and an output with a frequency divided into 1/16 is generated at output terminal D. That is,
These outputs are shown in Figure 16-b, 231', respectively.
A, 231'B, 231'C, and 231'D. However, in Figure 16-b, 222'
is the clock pulse generator 2 in Figure 16-a.
A signal inputted from the output terminal 222 of the counter 21 is applied to the CP terminal of the counter 231 via the inverter 230, so that the rising portion of the signal 222' becomes the trigger point. Note that the clock pulse signal at terminal 222 is hereinafter written as CLCK. Furthermore, when 1 is added to the CLEAR input terminal of the counter 231, the output terminals A, B, C, and D all become 0, and the state at this time is the 0th and 16th clock pulses as shown in Figure 16-b. The result is exactly the same as when adding . Also, unless 1 is added to the CLEAR terminal, the output state repeats the 0th to 15th states, and in the following explanation, when 1 is added to the CLEAR terminal, clock pulses corresponding to the 0th and 16th states are applied. 16th clock is added. In FIG. 16-a, the following three types of reset signals are applied to the CLEAR terminal of the counter 231 in order to effectively operate other circuits. First, a reset signal from the terminal 208 is applied to one input terminal of the three-input NAND gate 225 as a reset signal when the power is turned on, and a signal CBBP (details will be described later) indicating that the document table (Fig. 1, 2) has come to the reverse position. An inverted signal of 1) is applied from terminal 223 to another input terminal of gate 225. A pulse signal indicating the end of post-rotation is applied to the other input terminal of the gate 225, and this can be created as follows. First, signal LRT indicating that the rear rotation is in progress.
(Details will be described later) The inverted signal of
is first applied directly to one input terminal of the two-input AND gate 242, and then to the inverter 227,
228 and 229 to other input terminals. At this time, as shown in Figure 16-c, terminal 2
signal 224' at 24 and inverter 229
The signal 22 is in an inverse relationship with the output 229' of the
4', the signal 229' is delayed because it passes through three inverters. If this delay time is TD, the output signal of the gate 242,
As shown in the figure, 242' is TD time 1 from the falling edge of LRT, that is, the rising edge of signal 224' to the falling edge of signal 229'. After this, a signal indicating the end of rotation (hereinafter referred to as LRTEP) is output from the terminal 243 to other circuits, and further to the inverter 2.
26 to gate 225. Therefore, it becomes a reset signal. The output signal 225' of the gate 225 is STOP, CBBP,
When either LRTER becomes 1, it is output as 1 and the counter 231 is reset (cleared). Next, the outputs of the counter 231 are further combined as follows. First, the two-input AND gate 235 has an inverter 23 with a C terminal output and a D terminal output.
The D terminal inverted output via 4 is applied to each input terminal, the output of the gate 235 and the B terminal output are applied to each input terminal of the two-input AND gate 236, and the three-input AND gate 237 has the The C terminal inverted output and the D terminal output via the inverter 233 of the B terminal output and C terminal output are applied to each input terminal, and the three input AND gate 238 receives each of the B, C, and D terminal outputs. The inverted output via the inverters 232, 233, 234 is
applied to each input terminal. Therefore each
The output of the AND gate is as shown in Figure 16-b, and the output 239' of the gate 235 is 4th to 7th.
period 1 of the second clock pulse, gate 2
The output 240' of gate 36 becomes period 1 of the 6th to 7th clock pulse, and the output 240' of gate 237 becomes the period 1 of the 6th to 7th clock pulse.
1' is the period 1 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, and 2 are connected to each other.
From 41,211, 4CP, 6CP, 10CP, 1
Output as 6CP signal. In addition, in this embodiment, the above-mentioned clock pulse is
15.75 occur. This means that in the 16-bit counting method described above, by counting 16 clock pulses, it is possible to effectively know that the drum has made approximately one revolution.

(Size Circuit) Next, the copy size signal generation circuit will be explained with reference to FIG. In this embodiment, in order to improve the time efficiency of the copying process, an endless photosensitive drum is used as described above, and control is performed according to each copy size. Each copy size is automatically determined as soon as the transfer paper cassette is inserted into the main body. Specifically, the circuit shown in Figure 17 determines whether there is no cassette, B4 size cassette, A4 size cassette, or B5 size cassette. Four types of states are distinguished.

In FIG. 17, micro switches 246, 2
47 are both in the open state (when no cassette is inserted), and at this time, the output sections 246' and 247' are connected to the power supply voltage Vcc via resistors 248 and 249, respectively, so they are in the signal state of 1. ,
By inserting the cassette, each micro switch 246,
When 247 is switched and turned ON, output section 2
46' and 247' are connected to a zero potential part GND (earth) and have a signal state of 0. In this example
When a B4 size cassette is inserted, the micro switch 247 is switched to the ON state, and when an A4 size cassette is inserted, the micro switch 246 is switched to the ON state, and when a B5 size cassette is inserted, the micro switch 247 is switched to the ON state. Both switches 246 and 247 are switched to the ON state. Here, the two-input AND gate 252 includes output parts 246' and 24 of the microswitch.
7' is applied to each input terminal, and a two-input AND gate 253 receives the signal at output 247' and the inverter 251 at output 246'.
A signal via the inverter 250 at the output section 247' is applied to the two-input AND gate 254, and a signal at the output section 246' and a signal via the inverter 250 at the output section 247' are applied to the two-input AND gate 254.
5 are applied with signals via inverters 250 and 251 of output sections 246' and 247', respectively. Therefore, the output of gate 252 becomes 1 when no cassette is inserted, and is output from terminal 256 as a no-cassette signal (hereinafter referred to as CEP), and the output of gate 253 becomes 1 when a B4 size cassette is inserted, and becomes B4. It is output from the terminal 257 as a size copy signal (hereinafter referred to as B4C), and is similarly output from the gate 254 and the gate 255.
The output of each is an A4 size copy signal (below
A4C) is output from terminals 258 and 259 as a B5 size copy signal (hereinafter referred to as B5C).

(Copy Execution Command Circuit) Next, a copy execution command signal (hereinafter referred to as CCMD) generation circuit is shown in FIG. First, circuit 261
In Figure 16-a, similar to circuit 221, using a magnet and a Hall element, when the copying machine user presses the copy button (Figure 2, 13), the magnet moves and the resulting magnetic field strength is generated. This circuit has the output of a Hall element that detects changes in the value using the Hall effect, performs electromagnetic conversion, and generates an output of 1 when the copy button is pressed. This output is connected to terminal 264 as CCP. and is applied to one input terminal of the four-input AND gate 270. A circuit 262 is a circuit that outputs 1 as LEP when the developer becomes low in the developing device (FIG. 1, 24), and in this embodiment, like the circuit 261, a pair of a magnet and a Hall element is used. This output LEP is applied from terminal 265 via inverter 267 to another input terminal of gate 270. In addition, the circuit 263
is a circuit that outputs 1 as PEP when there is no paper left in the cassette. In this embodiment, the lamp and the CdS photosensitive element are made to face each other, and the paper in the cassette is interposed between them. The circuit detects the presence or absence of paper by utilizing the fact that the CdS is strongly irradiated with the light emitted from the lamp when the paper runs out.When the paper runs out, this output becomes 1 as a PEP signal and is sent from the terminal 266 to the inverter 26.
8 to another input terminal of gate 270. Furthermore, CEP generated from the circuit shown in FIG.
9 to another input terminal of gate 270. Therefore, the output of the gate 270 is that the copy button is pressed and CCP becomes 1, the developer is filled and LEP becomes 0, and there is transfer paper in the cassette so PEP becomes 0 and the cassette itself is loaded. When CEP is 0, it becomes 1 and is output from terminal 271 as CCMD.

(Copy execution signal generation circuit) Next, a signal indicating that a copy operation is in progress.
FIG. 19 shows a circuit that generates CEXC (hereinafter simply referred to as CEXC). The signal CEXC starts when the copying machine starts moving forward to copy the first page after the copying machine is powered on, and after the last copy is completed, as will be explained in detail later. This is the signal for period 1 when the post-rotation ends, and terminal 2 is first
From 76, the document table advance command signal CBFOR is applied to the S terminal of FF 281 via inverter 282. Therefore, as will be described later, the FF 281, which has been reset in advance by the STOP 0 signal when the power is turned on, has an output Q of 1 when the first document table advance command signal CBFOR becomes 1, and is outputted from the terminal 283 as CEXC. In addition, since the signals including the reset signal, jam detection signal, and charger abnormality signal when the power is turned on are applied from the terminal 208 to one input terminal of the two-input AND gate 280, when the signal becomes 0, the output of the gate 280 also becomes 0. Since this output is further applied to the terminal of FF281, the output Q becomes 0 and CEXC is stopped. Also FF
The reset of 281 is further inputted from terminal 243. This is also done by the LRTEP signal going to 1. As explained in FIGS. 16-a and 16-c, LRTEP is a signal that becomes 1 only during the time TD at the end of the post-rotation, and is applied from the terminal 208 to one input terminal of the two-input NAND gate 279. Also, since the CCMD signal is applied from the terminal 271 to the other input terminal of the gate 279 via the inverter 278, LRTEP is inverted and applied to the gate 280 only when CCMD is 0, but this is
This is to prevent CEXC from being reset even if the copy button is pressed during post-rotation and CCMD becomes 1, and as will be described later, even if LRT falls at this time.

(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.

This copier is powered on and each circuit goes up to WUP.
After being reset by a signal, the drum rotates once as a forward rotation, and if the copy button is not pressed at this time, the drum stops rotating and enters a rest state. When the copy button is pressed in this pause state and CCMD becomes 1, the cleaning blade (Fig. 1 34) marks that may be formed on the drum when the drum is stopped are avoided when copying the first sheet. To wait for a delay in the lighting time of the fluorescent lamp, the advance of the document table is started after waiting 4 clocks, and when the latent image of this first copy is formed, the drum is placed immediately before the primary charger (Fig. 1, 21). The drum photosensitive layer is exposed to light to compensate for differences in the condition 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 this as a signal to turn on the pre-exposure strongly when copying the first sheet.
This is a circuit that generates the BRIGHT signal. first
As described in the CEXC generation circuit (FIG. 19), the state where CCMD is 1 and CEXC is 0 appears only immediately before the first copy is executed. CCMD
The signal is from the terminal 271 to the two-input NAND gate 293
CEXC is applied to one input terminal of the gate 29 through an inverter 289 from the terminal 283.
3 to the other input terminal. Therefore this
When CEXC is 0 and CCMD is 1, the output of gate 293 becomes 0, which is added to the S terminal of FF295, and the output Q of FF295 becomes 1, making terminal 29
8 is output as a BRIGHT signal. BRIGHT
The pre-exposure illuminance, which has become strong when the signal becomes 1, must be returned to weak illumination after the drum has made approximately one rotation in order to achieve the above-mentioned purpose. Therefore, in the case of A4 size copy or B4 size copy, there is a signal indicating that the document glass has reached the A4 size reverse position.
When A4BP (details will be explained later) becomes 1, or in the case of B5 size copy, the document glass does not reach the A4 size inversion position, so the document glass becomes B5.
Reach the size reversal position and move to the 16th position as described above.
- Figure a The counter 231 is reset, and then the fourth clock pulse is input, and when the rising 4CP signal is output, the FF 295 is reset and the high intensity irradiation of the pre-exposure is stopped. There is. In the circuit, first the terminal 287
from inverter 291 and three-input AND gate 2
The A4BP signal is applied to the terminal of FF 295 via 97. Therefore, when A4BP becomes 1, 0 is added to the terminal, and the output Q becomes 0. Also, A4BP is 1
When the FF295 is not reset and the 4CP signal rises, this signal is transferred from the terminal 288 to the FF295.
Since the D terminal is connected to the CP terminal of the FF295 and the D terminal is connected to GND (earth), the output Q of the FF295 becomes 0. Here, as a signal for resetting the FF 295, STOP and CEXC are inverted and applied from the terminal 283 to one input terminal of the two-input NAND gate 294 via the inverter 289, and the other input terminal is supplied from the terminal 271 via the inverter 289. 2
CCMD is added via 92. The outputs of the gates 294 are respectively routed through gates 297.
Added to FF295. This is because STOP, which is a reset signal when the power is turned on, resets FF295, and CCMD is 1 and CEXC is 0, and after setting FF295 (output Q is 1), 4CP is rising
Even if CBFOR rises, if CCMD becomes 0 before CEXC rises, the document glass will not move and copying will not be performed. CEXC is 0 and CCMD
becomes 0 and is reset at the output of gate 294. Here, the 4CP signal is applied to the CP terminal to reset the FF295 during B5 size copying, but even if the 4CP signal rises after CCMD becomes 1, the document platen advance command signal CBFOR is becomes 1 due to the rise of
Because CEXC rises due to the rise of CBFOR
Immediately after 4CP rises, CEXC remains 0, and at this time, FF 295 is not reset by the rise of 4CP.

(Rear rotation command circuit) Next, the rear rotation command signal LRT generation circuit is connected to the 21st -
Fig. 21-b shows and explains the time chart of Fig. 21-a. In this embodiment, the post-rotation is performed after the latent image formed and developed on the photosensitive drum in the last copying process is transferred to the transfer paper, and ends after the drum has rotated approximately one revolution. First FF30
5 is a two-input AND gate 304 from the terminal 208
A STOP signal applied to the terminal via
When the power is turned on, it is reset and the Q output and output become 0 and 1, respectively. Next, the 10CP signal is sent to terminal 24.
1 to the CP terminal of the FF305, but this signal becomes 1 during forward rotation, when the document table is moving forward, and when the document table reaches the reverse position and the counter 231 in Figure 16-a is reset. Occurs at the end of the transfer after being transferred. Therefore, first, input three CEXC from terminal 283 to the D terminal of FF305.
CBFOR from terminal 276 through inverter 301 in addition to one input terminal of AND gate 303
Add the inverted signal of
By adding the output of FF305 to another input terminal and adding the output of its gate 303,
The FF 305 is set and the Q output becomes 1 only when CEXC is 1, CBFOR is 0, and LRT is 0, and the FF 305 can be set by 10CP generated at the end of transcription. becomes. However, since CCMD is inverted and applied from terminal 271 to the terminal of FF305 via gate 304, FF305 is actually set when CCMD disappears and becomes 0 (when the copy button is turned off). time), that is, when the last copy is being made.

This also means that FF305 is set.
If the copy button is pressed and CCMD becomes 1 while LRT is 1 and the rear rotation is being executed, the rear rotation will be stopped at that point and the vehicle will move forward. It resumes forward movement without requiring 4 clocks. Also, 1
After the 0CP signal rises to 1, the 10CP signal rises again when 16 clock pulses are generated, as described in the explanation of FIG. 16-a. Therefore, during this time, the drum rotates approximately once,
Also, at this time, the FF added to the gate 303
Since the output of FF 305 is O and the D terminal is 0, the output Q of FF 305 is reset to 0 and the post-rotation ends. In addition, the output Q of FF305 is connected to terminal 30 as LRT, respectively.
6,224 to other circuits. 21st-
Figure b shows the time chart. Signal 208',2
71', 276', 283', 241', 306' are terminals 208, 271, 276, 283, respectively.
In the signal waveforms at 241 and 306, after two consecutive copies, the 10CP signal rises and LRT rises, but after this, one copy is performed again after rotation. .

(Original platen reciprocating circuit) Next, the document platen forward and backward command signal generation circuit is connected to the second
It is shown and explained in Figure 2. First, to explain the document table movement sequence, forward rotation is performed after the power is turned on, but after the forward rotation is completed (at this time, CEXC is still 0).
However, when CCMD 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. When it reaches each reversal position of B5, A4, and B4, it starts moving backwards and returns to the original platen 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, the document table automatically moves to the home position.

In this embodiment, the position detecting device for these document tables uses a pair of magnet and Hall element, similar to the clock pulse generator shown in FIG. 16-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 B5,
A signal indicating that the reversal position has been reached for each copy size of A4 and B4 is generated. That is, when the copy size is B5, when the magnet 161 provided on the document table reaches the magnetic sensing element 48A, the reversal position signal B5BP is output from the magnetic sensing element 48A. Similarly, in the case of A4, the magnetic sensing element 48
A reversal position signal A4BP is output from B, and in the case of B4, a reversal position signal B4 is output from the magnetic sensing element 48C.
BP is output. In the circuit shown in FIG. 22, a signal CBHP (hereinafter referred to as CBHP) indicating that the document table is at the home position is applied from a terminal 311 to one input terminal of a two-input AND gate 315, and a signal CCMD from a terminal 271 is applied to the other input terminal. is applied to the input terminal of Therefore, if CCMD 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, from the terminal 222, the two-input NAND gate 31
Since the CLCK signal is applied to one input terminal of the gate 316 and the CEXC from the terminal 283 is applied to the other input terminal of the gate 316, when CEXC is 1, an inverted signal of CLCK is output from the gate 316. Two more inputs
The 4CP signal from the terminal 288 is applied to one input terminal of the NAND gate 319, and CEXC is applied to the other input terminal via the inverter 318, so when CEXC is 0, the 4CP signal from the gate 319 is applied to the NAND gate 319.
An inverted signal is output. These gates 316,
The output of 319 is further applied to the input terminal of a three-input NAND gate 317, and the gate 317 also has an FF
The output of H.324 is applied to the input terminal. accordingly
When the output of FF324 is 1, from gate 317
CLCK or 4CP signals are respectively gate 3
16, 319 and added to the CP terminal of the FF 324. Therefore, when copying the first sheet, that is, when CCMD and CBHP become 1 when CEXC is 0, the FF 324 is set at the rising edge of the 4CP signal, the output Q becomes 1, and the document platen advance command CBFOR ( Hereafter simply written as CBFOR). Therefore, even after the forward rotation of 4CP, the conditions for advance are that the copy command is still valid and that the document table is at the home position. Therefore, since the displacement of the document table during the forward rotation can be monitored, accurate image formation is possible. can.

In addition, when copying the second and subsequent sheets, CEXC is already set to 1 at this time, so when the document table returns to the home position and CBHP becomes 1, CBFOR is set by the rising edge of the next input CLCK signal. 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 an image at any position on the drum surface is not lost, and the pre-rotation time before the start of advance for the first sheet is reduced by 2. Coupled with the fact that the information is not added after the first sheet, the time required for repeated copying can be extremely shortened. Next, the document table is reversed using the three-input AND gate 322.
The output of is passed through the two-input AND gate 323,
This is done by adding it to the terminal of FF324. In other words, for B5 size copy, use B5C.
A signal is applied as 1 from terminal 257 to one input terminal of two-input NAND gate 320 B5BP
is applied from terminal 312 to the other input terminal. Therefore, when B5BP becomes 1 at this time, it is inverted through gates 320, 322, and 323 and becomes FF.
324 terminal and resets the FF324. In the case of A4 size copy, the A4C, which is input from terminals 258 and 287 respectively,
The A4BP signal is applied to each input terminal of two-input NAND gate 321, and the output is also applied to one input terminal of gate 322. In addition, in the case of B4 size, from terminal 313, B4BP is connected to inverter 32.
7 and is inverted and applied to the other input terminal of gate 322. Therefore, each original platen reversal signal is inverted via gates 322 and 323 and applied to the terminal of FF 324, and at this time, the output becomes 1, and the original platen reverse command signal CBREV ( Below simply
(written as CBREV) from the terminal 326 to other circuits. However, when the document table returns to the home position at gate 325 and CBHP becomes 1,
Since 0 is applied to one input terminal via the inverter 314, CBREV becomes 0 and reverse movement is stopped. If the document table is not at the home position when the power is turned on, it is automatically moved to that position by the output applied to the gate 325 via the inverter 314 and the output of the reset FF 124, which together set CBREV to 1. It is from. Therefore, it is possible to automatically move to the home position until just before the forward movement starts.
Note that STOP 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, the 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 platen inversion position signal, and the output is output from the terminal 22.
3 to other circuits. Figure 22-b is
In the circuit shown in Figure 22-a, CCMD and
31 in the time chart when CEXC is 1
The signal waveforms shown at 1', 222', 322', 276' and 326' are CBHP, CLCK, , respectively.
Compatible with CBFOR and CBREV.

(Paper feed circuit) Next, paper feed start command signal PFSD (hereinafter simply
Figure 23 shows the generation circuit (written as PFSD). In the figure, from the terminal 331, a signal indicating that the document table has reached a specific position is generated by the magnet 161 and the element 71, using means completely similar to the document table reversal position detection means shown in FIG. 22-a. The paper feed timing signal PFSP can be input as two inputs
It is applied to one input terminal of AND gate 332. Other input terminals of gate 332 include terminal 27
Since CBFOR is added from 6, if the PFSP is input as 1 while the document table is moving forward, the gate 33
The output of 2 becomes 1, which 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-input AND circuit, and the output thereof is used as a count signal for the number of copies. That is, in Fig. 23, B
5C, A4C, and B4C are terminals 259 and 2, respectively.
58, 257, and in addition to one input terminal of two-input AND gates 333, 334, 335, the output of each gate is B5COUNT, A4COUNT, B4 from terminals 337, 338, 339, respectively.
Output as COUNT.

(Jam Detection Circuit) Next, we will discuss the circuit for detecting abnormal transport of transfer paper in the copying process, that is, extreme delays, banding in the transport path, etc. (hereinafter simply referred to as jam).
The circuit diagram and time chart are shown in Figures a, b, and c for explanation. First, in FIG. 24-a, the signal whose generation process was explained in FIG. 22-a is inputted from the terminal 223 and applied to the SD terminal of the FF 344 as a set signal. Therefore, when Q becomes 0, the output Q of the FF 344 becomes 1, and this signal is further applied to one input terminal of the two-input NAND gate 345. Also, the other input terminal of the gate 345 receives the jam timing signal JTP from the terminal 342.
(hereinafter simply referred to as JTP) is added. This JTP
When the leading edge of the transfer paper reaches a specific position within a predetermined path after the transfer paper has completed the transfer process and also completed the drying and fixing process, there is a slight difference in the time it takes to reach it through the normal conveyance process. This is a pulse signal that is generated after the time with a margin has passed.When the output Q of FF344 is 1 and JTP becomes 1, the output of the gate 345 becomes 0, and it is added to the SD terminal of FF346, and the output of FF344 becomes 0.
Set 46. In other words, the output Q of FF346 is 1
As a result, the jam generation signal JAM is output to terminal 343.
is output from. In addition, the inverted signal of JAM is FF3
46, that is, output from the terminal 201 to other circuits. If the transfer paper is conveyed normally, a signal from the paper detection device at the specific position is sent.
PDP (hereinafter simply written as PDP) is connected from terminal 341.
It is added to the CP terminal of FF344 and the D terminal is connected to GND.
Since it is connected to (ground) and becomes 0, the PDP
FF344 by the signal rising from 0 to 1
The output Q of becomes 0, and at the gate 345 JTP
Even if becomes 1, the output does not become 0 and FF 346 is not set. In the time chart of FIG. 24-c, part A shows the signal waveforms during normal transport, and part B shows the signal waveforms when a jam occurs. However, signal waveforms 223', 341', 342', 344', 343'
are the signal waveforms of PDP, JTP, Q output of FF344, and Q output (JAM) of FF346, respectively. The broken line portion in the signal 341' indicates the case where the transfer sheet has not reached the specific position or has reached the specified position extremely late. In this embodiment, the paper detecting means at the specific position uses a pair of a lamp and a CdS photosensitive element, similar to the paper detecting device described in connection with the PEP signal generating circuit in FIG. 18.

Next, regarding the JTP generation circuit described above, the circuit shown in FIG. 24-b was used in this embodiment. In this embodiment, as shown in FIG. 16-a, the clock pulse counter 231 is reset at the document table inversion position, and after that, the leading edge of the transfer paper reaches the specific position by normal conveyance. ,
For each size of B5, A4, B4, 10CP each,
Approximately 1 second before the 6CP and 4CP signals are generated,
Therefore, each count signal serves as a jam timing signal. That is, as shown in FIG. 24-b, while the A4C signal from the terminal 258 is applied to one input terminal of the two-input NAND gate 348, the 6CP signal from the terminal 240 is applied to the other input terminal. Therefore, the output of gate 348 is 6CP signal inverted and 3 inputs only in case of A4 size copy.
It is applied to one input terminal of NAND gate 350. Also, in case of B4 size copy, terminal 257,
B4C and 4CP are input from 239, respectively.
It is applied to the input terminal of a two-input NAND gate 349 and the output of gate 349 is applied to the other input terminal of gate 350. Also, the 10CP signal is
Inverted via inverter 347 to gate 350
is added to another input terminal of . Therefore, in the case of B4 size copy, 4CP and 10CP signals appear in the output of gate 350, and in the case of A4 size copy, 6CP and 10CP signals appear, and in the case of B5 size copy, only the 10CP signal appears, It is output from the terminal 342 as a JTP signal. Note that, apart from this embodiment, the JTP signal can be generated regardless of the copy size, for example, when the document table starts moving forward or after a certain period of time has elapsed from the time when the paper feed start timing pulse is generated. In this way, since the clock pulse count for forming the jam timing signal is started by detecting the position of the document table, there is no need to select the output compared to the case where the count results are repeatedly output as the drum rotates.

Further, the jam detection operation will be specifically explained using FIG. 27. First, use FF344 as the document platen reversal position signal CBBP (B4BP for B4, A for A4).
4BP, B5BP in the case of B5), and this FF 344 is reset by the paper detection signal PDP.

(a) For B4 size If it is reset by paper detection before the 4CP pulse signal is generated, it is normal (part A).
If the paper cannot be detected and the FF 344 is not reset before the occurrence of 4CP, the FF 346 is set as a jam (part B). This is set by an AND condition (gate 345) between the set output Q of the FF 344 and the jam timing signal (JTP).

Therefore, if FF344 remains set at the rise of 4CP, jam FF346 will be set, so even if 10CP is output as JTP afterwards, or even if the length of 4CP is long, subsequent circuit operation will be affected. it doesn't matter.

Of course, the same applies if the FF 344 has already been reset when 4CP rises, and even if 10CP is output later or the length of 4CP is long, it is still normal.

(b) For A4 size This is the same as replacing 4CP with 6CP for B4 size.

(c) For B5 size This is the same as replacing 4CP in B4 size with 10CP.

(Energization control circuit) Next, the aforementioned control signals are appropriately combined to control the energization switching element in order to energize each terminal element according to the process conditions of the copying process. When a pulse transformer is used as a triax and a triax ignition circuit, an output circuit is used, an example of which is shown in FIG. Figure 25 shows an example of a signal generation circuit that controls the energization of the main motor (M in Figure 5).
Terminals 271, 283, 2 are connected to drive the main motor when any one of them becomes 1.
COMD, CEXC, which are input from 16 respectively.
The INTR signals are applied to each input terminal of a three-input OR gate 408 for combination, and the output of the gate 408 is further applied to one input terminal of a two-input AND gate 409. Also, the output signal from the astable multivibrator circuit 402 is input to the other input terminal of the gate 409.
By adding OSC, the output of gate 409 causes an output from circuit 402 only when the output of gate 408 is 1, switching the energization from terminal 411 to the main motor. It is amplified and added to the pulse transformer in the triac's ignition circuit.

(Electrification Switching Circuit) The digital circuit that is the main part of the control circuit has been explained above, including sequence control. Next, FIG. 26 shows a circuit that switches the current applied to each terminal element according to the output of the control circuit. Shown below. In the figure, P is an AC input power supply, PL ₁ , RL ₂ , RL ₃ are each terminal element, G ₁ , G ₂ , G ₃ are triaxes for switching the current to each terminal element, T ₁ ,
T ₂ and T ₃ are trigger pulses generated from a normal triax trigger generation circuit (not shown), and the signals from the control circuit (for example, Fig. 25)
It was generated according to Also, S ₁ , S ₂
is a two-circuit main switch that operates. Therefore, RL ₁ can be energized by generating the trigger signal T ₁ until a predetermined sequence is completed, regardless of whether the main switch is ON or OFF. In this circuit example, RL ₁ includes the main motor, high voltage AC output, etc. RL ₂ also has main switches S ₁ and S ₂
When S ₂ is turned on, a trigger voltage is applied to g ₂ via resistor R ₂ , making G _{2 conductive and allowing electricity to flow.Furthermore, even if the main switch is turned OFF, the trigger voltage from the control circuit can be applied to g 2} . RL ₂ continues to be energized as long as the signal T ₂ is generated, and in this circuit example corresponds to a power transformer for maintaining the control state. Furthermore, in RL ₃ , the main switch remains OFF even if the trigger signal T ₃ from the control circuit is generated.
When this happens, power supply stops, and this example circuit includes the fuser heater and the like. Here, by including the power transformer of the power supply circuit for applying power supply voltage to the control circuit in RL ₂ , the control circuit can be operated even when the main switches S ₁ and S ₂ are turned off. It is necessary to put it in the state. It should be noted that the power supply circuit and the trigger pulse generation circuit may be ordinary ones, and other associated circuits not directly related to the present invention may be ordinary ones, and have been omitted for the sake of simplifying the explanation.

In addition, in Figure 26-a, if it is necessary to cut both sides of the input power supply of each terminal element included in RL ₃ , the connection of point t may be changed from point u to point s, and RL ₂ As shown in Figure 26-b, the current-carrying circuit is connected to one line L ₁ from the AC input power source P with S ₁ ,
Connect one terminal of each of S ₂ and make S ₁ a conductive path to each terminal element corresponding to the pair _of RL ₃ and G ₃ ,
The above effect can also be obtained by supplying a trigger voltage from _g2 through _R2 .

In addition, here is a switch that directly turns the power on and off.
Although we have described the case where S ₃ and S ₄ are in the on state, it is convenient to use these switches S ₃ and S ₄ as door switches for the case of the copying machine. In other words, when performing jam removal after detecting a jam, opening the door shuts off this switch and turns off the voltage applied to switching elements G ₁ , G ₂ , and G ₃ , so conduction to all loads and control circuits is turned off. Furthermore, sufficient safety can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the copying device, Fig. 2 is an external perspective view thereof, Fig. 3 is a longitudinal sectional side view of Fig. 1, and Fig. 4 is a longitudinal sectional view of the copying device.
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, and FIG. 8 is a perspective view showing the fixing device.
FIG. 9 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, and FIGS. 12 and 13 are the document table stop device. 14a is the reset command signal generation circuit, FIG. 14b is its time chart, FIG. 15a is the pre-rotation signal generation circuit, FIG. 15b is its time chart, and FIG. 16a is the clock. Figure 16b is a time chart thereof, Figure 16c is a waveform diagram for clearing the counter, Figure 17 is a copy size signal generation circuit,
8 shows a copy execution command signal generation circuit, FIG. 19 shows a copy execution signal generation circuit, FIG. 20 shows a pre-exposure strong illuminance lighting command signal generation circuit, FIG. 21a shows a post-rotation command signal generation circuit, and FIG. 22b is the time chart, FIG. 22a is the document table, forward and backward command signal generation circuit, FIG. 22b is the time chart, FIG. 23 is the paper feed start command signal generation circuit, and FIG.
Figure a is a jam occurrence detection circuit, Figure 24b is a jam timing signal generation circuit, Figure 24c is a time chart thereof, Figure 25 is a signal generation circuit for controlling conduction, Figures 26a and 26 Figure b is a circuit that switches conduction to each terminal, Figure 27a
is a time chart for explaining jam detection for B4 size, Figure 27b is a time chart for explaining jam detection for A4 size, and Figure 27c is for explaining jam detection for B5 size. This is a time chart for
A, 48B, 48C, 71, 72 are magnetic sensing elements, 161, 162 are magnets, and in Fig. 22-a, CBHP...document platen home position signal, CCMD...copy execution command signal, CLCK...clock pulse signal,
CEXC...Copy execution signal, 4CP...Counter pulse signal, 324...Binary counter, CBFOR
...Original plate forward command signal, CBREV...Original platen backward command signal, B5C, A4C...Cassette size signal,
B5BP, A4BP, B4BP...Original platen position detection signal, CBBP...Original platen inversion position signal, STOP...Reset signal.

Claims (1)

[Scope of Claims] 1. A copying apparatus that exposes an image onto a photoreceptor and transfers the exposed image to a copy material, comprising: a reciprocating member for exposing and scanning a document; a means for detecting the size of a copy material storage section; a copy material detection means provided in the copy material path; a memory for outputting a jam signal; a means for generating a series of pulses at least during rotation of the photoreceptor; and the reciprocating member according to the size detected by the size detection means. means for varying the reciprocating distance of the reciprocating member; means for starting feeding the copy material towards the copy material path in synchronization with the movement of the reciprocating member; and counting the pulse a predetermined number of times based on the inverted position of the reciprocating member. counting means for starting, and when the copying material has not reached the copying material detection means at the end of counting a predetermined number of counts by the counting means, the memory is set by a count signal of the predetermined number by the counting means and a jam signal is outputted; A copying apparatus comprising: a control means for changing the count number of the counting means after the reciprocating member finishes forward movement according to the size of the copying material.