JPS6118185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer type copying apparatus having an endless photoreceptor. 2. Description of the Related Art Copying apparatuses that use an endless photoreceptor to continuously make a desired number of copies are known. When this is applied to a reciprocating scanning type copying device, it is possible to take advantage of the advantage of being able to start copying from any position on the endless photoreceptor by turning off the driving force of the original scanning system and simultaneously applying a driving force in the opposite direction. Continuous copying can be performed in as short a time as possible. However, the shock applied to the reciprocating member when switching the driving force is large, and there is a possibility that accuracy may be deteriorated. The present invention eliminates this inconvenience, and has the advantage of being able to start copying from any position on the surface of the rotating body, without sacrificing the short copying time, and enables image formation at any position. a rotating body having an endless photoreceptor, a reciprocating member for exposing and scanning a document to form an image on the rotating body, means for transferring the image formed on the rotating body to a transfer material, and a series of pulses. means for causing the reciprocating member to move forward from the forward movement start position for exposure scanning; return movement means for returning the reciprocating member to the start position after the end of the forward movement; storage means for outputting a drive signal to the reciprocating means to cause the reciprocating member, which has returned to the starting position during copying, to reciprocate; A copying apparatus characterized by comprising a control means for setting the storage means based on pulses from the generating means, outputting a drive signal to the reciprocating means, and starting image formation from an arbitrary position on the photoreceptor. . That is, in FIG. 22, the pulse is 222, the storage means is 324, and the control means is 3.
16,317, CP, drive signal 276 corresponds,
The forward movement start position corresponds to 72 (FIG. 4). (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 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, the characteristics of the photoreceptor become the same for the first 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 Because the cleaner is pressed against the drum with considerable pressure, it is inevitable that the same portion of the photoreceptor undergoes 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 time to time, and it is also possible to use the photoreceptor over its entire length without fading, 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 performed 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. In addition, instead of the microswitch that has been conventionally used in many devices of this type, a non-contact type position detection device using a magnetic detection element is often used. These are used for the liquid level detection device, clock pulse generator, copy 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. By using this in a device that attaches a magnet to all movable parts and detects changes in magnetic flux intensity due to the movement of the magnet at a specific position using the Hall effect or the effect of changes in the resistance of semiconductors due to magnetism, the following can be achieved. You can get a great effect. 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, the wrinkle is approximately 16 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 is equal to the 16 CP when the copy button is turned on, plus 4 CP.
rotates, and only then the document table 2 with the document placed on the document table glass 5 starts, is illuminated by the illumination lamp 16, and its image is reflected by the reflecting mirror 17,
An image is formed on the drum 15 at the exposure section 19 by 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 copy 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.
It is AC charged 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. Developing device 24
A container 26 for storing the developer 25, a pump 27 for stirring the developer and pushing it up to the developing electrode section, a developing electrode 28, and a device installed on the drum to remove the fog if there is a fog on the image developed on the drum. It consists of electrode rollers 29 which rotate in close proximity and one of which is grounded. The developing electrode 28 is
A constant interval is always maintained on the photosensitive drum 15, and the electrostatic latent image formed on the photosensitive drum 15 is developed by the toner in the developer 25 pushed up onto the developing electrode 28 by the pump 27, and Be visualized. Next, the photosensitive drum 15 is charged with high voltage from the high voltage power source 20 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 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 supply 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, turn on the main switch 10 mentioned earlier, the drum will rotate by an amount equivalent to 16CP, and the 16CP+
To explain why the document table 2 starts moving only after the drum has rotated by 4 CP, this machine uses an endless type photosensitive drum, so no surface of the photosensitive drum can be used for image formation. I am now able to contribute. Therefore, when it comes to increasing the number of copies per unit time by eliminating unnecessary rotation as much as possible, first of all, the blade cleaner edge portion 35 is used for the first rotation of the drum.
In the worst case scenario, if any amount of toner remaining on the drum dries and sticks to the drum when the machine is not used, for example, for one cycle or ten days, this may lead to the formation of a latent image. This is because the photosensitive drum needs to be cleaned first. Next is 4CP, but this 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 by pushing up the middle plate 37 upwardly by a spring 38, the transfer paper 7 is always separated by the separating claws 3 provided on both sides of the tip of the cassette 6.
It's being pushed to 9. 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 document table reaches the 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 to feed the cassette 6. The topmost transfer paper in the transfer paper is contacted, and the separation claw 39 separates one copy of the transfer paper and sends 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 transfer paper 7 sent out from the cassette 6 remains in contact with the contact portion of the register rollers 41 and 42. A slack is created between the guides 43 and 44. 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 placed on the photosensitive drum 1.
It is sent at a speed that matches the circumferential speed of No. 5. 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 transferred to the ejection tray by ejection rollers 45 and 46.
It is discharged at 47 . 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 2 moves to the left in FIG. 1 in synchronization with the circumferential speed of the photosensitive drum 15 in response to a document table start signal after 4CP from the clock pulse generating mechanism, and performs 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. Since the return speed is high as described above, a shock is likely to occur when stopping, but in this machine, the shock is absorbed by a brake mechanism, which will be 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 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 captures the movement of the document table 2, performs counting, and
Since the switch element is held until the set number of copies is counted, 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 platen reversal signal generating 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, it 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, if a certain copying operation is completed and a certain period of time has passed and the next copying operation is not performed, the main switch 10 is turned off.
Even if it is ON, the drum automatically stops and enters a rest 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 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 begin to move forward. This copying machine enters the hibernation state 26CP 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 in a single cantilever manner 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, 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 side of the frame (the left end in Figure 1) when copying a book, etc., so that the entire page to be copied is placed well on the glass surface. The document table 2 is constituted by a case 4 provided for close contact. 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 the rolling motion of the 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, thereby regulating 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 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. The document table further moves forward, and when the exposure of each copy size (B5, 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 moves forward. Move from movement to return 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. A gear 88, which engages the aforementioned drum gear 56 at one end, drives a fixed drum drive shaft 89. , chain 8
6 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,
A document table drive wire 92 is wound several times, both of which are guided by a guide pulley 93 and fixed to the front and rear ends of a rear angle 77 that constitutes the document table. 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, 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 100 which is integrally fixed with the gear 99, one of which drives a gear 101, and a clutch 10.
The register rollers 41 and 42 are driven through the rollers 2 and 2. Further, the gear 100 meshes with the gear 103 and drives a paper feed roller control cam 139 via a clutch 137. drum gear 56
(FIG. 3) shows a gear 105 fixed to a separation shaft 104 meshing with a separation roller 106 to drive it. A rudder wheel 107 is fixed to the other end of the separation shaft 104, and the rudder chain 10
8. Discharge roller 11 via ladder wheel 109
0,111 is being driven. A gear 113 is integrally fixed to a sprocket wheel 112 driven from a sprocket wheel 85 attached to the main motor _M1 via a chain 86, and the gear 113 is connected to a clock pulse generating magnet 163 (see FIG. 4). ) engages with the gear 115 fixed to the arm 114 holding the magnet, rotates the magnet, and rotates the main motor _M1 by means of the magnetic detection element 164 (FIG. 4) fixed to the rear frame 50 and the magnet. Generates regularly spaced clock pulses synchronized with speed. Reference numeral 138 shown 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 paper feed roller 40 is constantly rotating.
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.
In other words, in order to shorten 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 forward movement and starts backward movement, heading toward the stop position at about four times the forward movement speed. 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 starting, and sufficient braking can be applied when stopping. A developing unit of a copying machine according to an embodiment will be described in detail with reference to FIGS. 1 and 3. FIG. 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. 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 the separation belt from becoming contaminated. 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 suction port 121 of the fan 120 engages with a conveying section 122 and is formed by a duct 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. A suction port 126 of the crossflow fan 120 is guided onto the hot plate through a blow-off 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 using a single fan, it is effective for downsizing the device and reducing costs.By forming a semi-circulating system, the surface of the transfer paper is not covered with saturated steam and is dried. is also good. 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 operate, 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 1 fixed to the machine
When the foot part 145 of the cassette 6 is placed on the cassette 44 and the cassette is pushed into the inside of the machine, the cassette 6 is held in a predetermined position by the spring 149 having the roller 148 so that the protruding part 146 at the bottom of the cassette comes into contact with the positioning plate 147 of the cassette stand. It is pressed into place. At this time, the cam 150 provided on the cassette side wall and the micro switch 15 installed on the cassette stand 144
1,152 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 paper discharge tray 47 has a hook portion 47a and a tray portion 47.
b 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 entire paper output tray 4
The cassette 6 can be easily attached and detached without removing the cassette 7 from the 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 with a level completely opposite to that of an inverted signal, and is expressed as XYZ. Also circuit 2
02 is 1 when a spark discharge occurs in the charger.
Although the detailed explanation is omitted here, the 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. Furthermore, 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 power-on, and when the specified period 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 in time intervals, 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.
The reason for outputting an inverted signal of STOP as the reset signal here 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 211.
is added to the CP pin, and when this 16CP rises, the pin becomes 0. The output of this terminal is further applied to one input terminal of a two-input NAND gate 215, and 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 terminal 216 as an inverted signal 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.
Highly reliable. 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 harmful 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. Also the first
In Figure 5-b, 211' and 208' indicate signals input from terminals 211 and 208, respectively. (Counting means) Next, the clock pulse counter circuit is connected to the 16th -
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'A,
231'B, 231'C, and 231'D. However, in Fig. 16-b, 222' is the clock pulse generator 221 in Fig. 16-a.
This signal is input from the output terminal 222 of the counter 231 and is applied to the CP terminal of the counter 231 via the inverter 230, so that the rising edge of the signal 222' becomes the trigger point. Note that the clock pulse signal at terminal 222 is hereinafter written as CLCK. Furthermore, counter 2
When 1 is added to the CLEAR input terminal of 31,
Each output terminal of A, B, C, and D is all 0,
The state at this time is exactly the same as when the 0th and 16th clock pulses are added, as shown in Figure 16-b. 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, there are three inputs from terminal 208 as a reset signal when the power is turned on.
An inverted signal of the signal CBBP (details will be described later) is applied to one input terminal of the NAND gate 225 and indicates that the document table (FIG. 1, 2) has come to the inverted position. applied to two input terminals. 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.
The inverted signal LRT (details will be described later) is at the terminal 224.
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' passes through three inverters, so there is a delay in the signal. If this delay time is TD, then the output signal of the gate 242 is 2
As shown in the figure, 42' 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 22.
6 to gate 225. Therefore,
This becomes a reset signal. Output signal 2 of gate 225
25' is STOP, CBBP, as shown in the figure.
When either LRTEP 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. Inverted outputs via inverters 232, 233, and 234 are applied to each input terminal. Therefore each AND
As shown in FIG. 16-b, the output 239' of the gate 235 is period 1 of the fourth to seventh clock pulses, and the output 240' of the gate 236 is period 1 of the sixth to seventh clock pulses. Then, the output 241' of gate 237 is 10
The output 211' of the gate 238 is the period 1 of the 11th clock pulse from the 16th (0th) clock pulse.
and the terminals 239, 240, 241, respectively.
211, output as 4CP, 6CP, 10CP, and 16CP signals. In this embodiment, 15.75 clock pulses are generated per rotation of the drum. 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.
Furthermore, when a B5 size cassette is inserted, both micro switches 246 and 247 are turned 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 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 output Q of the FF 281, which has been reset in advance by a 0 signal when the power is turned on, becomes 1 when the first document table advance command signal CBFOR becomes 1, and is output 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
The state where CCMD is 1 and CEXC is 0 is CEXC
As described in the generation circuit (FIG. 19), it appears only immediately before the first copy is executed.
The CCMD signal is applied from terminal 271 to one input terminal of the two-input NAND gate 293, and the CEXC
is applied from terminal 283 to the other input terminal of gate 293 via inverter 289. Therefore, when CEXC is 0 and CCMD is 1, gate 293
The output becomes 0, which is added to the terminal of FF 295, and the output Q of FF 295 becomes 1, which is output from terminal 298 as a BRIGHT signal.
The pre-exposure illuminance, which has become strong when the BRIGHT signal becomes 1, must be returned to weak illumination after the drum has rotated approximately once in order to achieve the above-mentioned purpose. Therefore, in the case of A4 size copying and B4 size copying, when the signal A4BP (details will be described later) indicating that the document table has reached the A4 size inversion position becomes 1, and in the case of B5 size copying, the original The stand is
Since the A4 size inversion position is not reached, the document table reaches the B5 size inversion position and the counter 231 in Figure 16-a is reset as described above.
After that, when the fourth clock pulse is input and a rising 4CP signal is output, FF29
By resetting 5, the high intensity irradiation of the pre-exposure is stopped. In the circuit, the A4BP signal is first applied from the terminal 287 to the terminal of the FF 295 via the inverter 291 and the three-input AND gate 297. Therefore, when A4BP becomes 1, 0 is added to the terminal, FF295 is reset,
Output Q becomes 0. Also, A4BP is not 1,
When the 4CP signal rises, this signal is sent from terminal 288.
In addition to the CP terminal of FF295, the D terminal is also connected to GND.
Since it is connected to (ground), the output Q of 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. CCMD is added via 292. The outputs of the gates 294 are applied to the terminals of the FF 295 via gates 297, respectively. This means that STOP, which is the reset signal when the power is turned on, is FF2.
95, and CCMD becomes 1 and CEXC becomes 0, and FF29
After setting 5 (output Q to 1), even if 4CP rises and CBFOR rises, if CCMD becomes 0 before CEXC rises, the document glass will not move and copy will not be performed. At this time, set CEXC to 0 so that the pre-exposure is returned to low illuminance.
CCMD becomes 0 and is reset at the output of gate 294. Here, the 4CP signal resets the FF295 when copying B5 size.
It is added to the CP pin, but after CCMD becomes 1.
Even if the 4CP signal rises, as will be described later, the platen advance command signal CBFOR becomes 1 when 4CP rises, and CEXC rises when CBFOR rises, so CEXC remains 0 immediately after 4CP rises. can be,
At this time, the FF 295 is not reset by the rise of 4CP. (Post-rotation command circuit) Next, the post-rotation command circuit 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 developed latent image formed on the photosensitive drum in the last copying step is transferred to the transfer paper, and ends after the drum has rotated approximately once. First FF30
5 is a two-input AND gate 304 from the terminal 208
The signal applied to the terminal through
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 at terminal 241
This signal is applied to the CP terminal of the FF 305 from 1 to 305, 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 shown in Figure 16-a is reset. Occurs at the end of the transfer. 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 to the input terminal of another, and then
By adding the output of FF305 to another input terminal and adding the output of its gate 303,
The FF305 is set and the Q output becomes 1 only when CEXC is 1, CBFOR is 0, and LRT is 0, and this occurs at the end of transcription.
By 10CP, the FF 305 is in a state where it can be set. 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). In other words, when the last copy is being made. This is even more FF
305 is set, LRT becomes 1, and the copy button is pressed while performing post-rotation.
When CCMD becomes 1, backward rotation is stopped at that point and the vehicle starts moving forward. It resumes forward movement without requiring 4 clocks. Further, after the 10CP signal rises to 1, 10CP 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 one revolution, and since the output of FF 305 applied to gate 303 at this time is O, and the D terminal is 0, the output Q of FF 305 is reset to 0. Post-rotation ends.
In addition, the output Q of FF305 is LRT, respectively.
The signal is output from terminals 306 and 224 to other circuits as a signal. A time chart is shown in Figure 21-b. Signals 208', 271', 276', 283',
241' and 306' are terminals 208 and 27, respectively.
In the signal waveforms at 1,276,283,241,306, after two consecutive copies, the 10CP signal rises and the LRT rises, but after this, the 10CP signal rises again after rotation.
The figure shows an example of a case in which copying is performed. (Original platen reciprocating circuit) Next, the document platen forward and backward command signal generation circuit is connected to the second platen forward and backward movement circuit.
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, an image can be formed while avoiding the part 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 magnet and a bare 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. Second
In the circuit shown in Figure 2, a signal CBHP is sent from the terminal 311 to indicate that the document table is at the home position.
(hereinafter written as CBHP) is a two-input AND gate 315
is applied to one input terminal of , and also from terminal 271.
CCMD is applied to other input terminals. Therefore, when the document table is in the home position, CCMD is 1.
Then, the output of gate 315 becomes 1, and FF3
It is added to the D terminal of 24. Also, from the terminal 222 to one input terminal of the two-input NAND gate 316
CLCK signal is applied to the other input terminal.
Since CEXC is added from 83, when CEXC is 1, the gate 316 outputs an inverted signal of CLCK. In addition, the 4CP signal from the terminal 288 is applied to one input terminal of the two-input NAND gate 319, and the CEXC signal is applied to the inverter 3 to the other input terminal.
18, so when CEXC is 0, an inverted signal of 4CP is output from gate 319. The outputs of these gates 316 and 319 are further three inputs.
It is applied to the input terminal of the NAND gate 317, and the output of the FF 324 is further applied to the input terminal of the gate 317. Therefore, when the output of the FF 324 is 1, the CLCK or 4CP signal is output 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 first sheet, that is, when CEXC is 0,
When CCMD and CBHP become 1, the FF 324 is set at the rising edge of the 4CP signal, and the output Q becomes 1, which is output from the terminal 276 as a document table advance command CBFOR (hereinafter simply referred to as CBFOR). Therefore, even after the 4CP's forward rotation, the condition for moving forward is that the copy command continues and the document table is at the home position. Therefore, since the shift 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 not adding data after the first copy, 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. That is, in the case of a B5 size copy, the B5C signal is applied as 1 to one input terminal of the two-input NAND gate 320 from the terminal 257, and the B5BP signal is applied from the terminal 312 to the other input terminal.
Therefore, at this time, when B5BP becomes 1, gate 32
Inverted via 0,322,323 to FF324
terminal and resets the FF324.
In the case of A4 size copy, terminal 25 is exactly the same.
A4C, A4BP input from 8,287 respectively
A 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 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 output to FF3.
At this time, the output becomes 1 and is outputted from a terminal 326 to other circuits as a document table backward movement command signal CBREV (hereinafter simply referred to as CBREV) via a two-input AND gate 325. However, when the document table returns to the home position at gate 325 and CBHP becomes 1, 0 is applied to one input terminal via inverter 314, so CBREV becomes 0 and backward movement is stopped. If the document table is not at the home position when the power is turned on, it will automatically move to that position due to the output applied to the gate 325 via the inverter 314 and the output of the reset FF 124.
This is because CBREV is set to 1. Therefore, it is possible to automatically move to the home position until just before the forward movement starts. In addition, STOP
Similarly to other circuits, the gate 323 is connected from the terminal 208 to the gate 323.
is applied to the R terminal of FF324 via. 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 table inversion position signal, and is outputted from the terminal 223 to other circuits. Figure 22-b is the same as Figure 22-a.
In the circuit shown in the figure, the time chart when CCMD and CEXC are 1 is 311', 22
The signal waveforms shown at 2', 322', 276', and 326' are CBHP, CLCK,, CBFOR, respectively.
Compatible with 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. This is input as the paper feed timing signal PFSP.
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 PESP is input as 1 while the document table is moving forward, gate 33 is applied.
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 Figure 23
B5C, A4C, B4C are terminals 259 and 25 respectively
8,257, two-input AND gate 3
In addition to one input terminal of 33, 334, 335, the output of each gate is output from terminals 337, 338, 339 as B5COUNT, A4COUNT, B4COUNT, respectively. (Jam Detection Circuit) Next, we will discuss the circuit for detecting the occurrence of abnormal conveyance of transfer paper in the copying process, i.e., extreme delays, binding in the conveyance 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 taken by 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.
Set 346. In other words, the output Q of the FF346 becomes 1 and is sent to the terminal 34 as the jam generation signal JAM.
Output from 3. In addition, the JAM inversion signal is FF
346, that is, output from the terminal 201 to other circuits. If the transfer paper is conveyed normally, the signal PDP (hereinafter simply referred to as PDP) from the paper detection device at the specific position is transmitted from the 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. Incidentally, a broken line portion in the signal 341' indicates a case where the transfer paper does not reach the specific position or the arrival is extremely delayed. In this embodiment, the paper detecting means at the specific position uses a lamp and a bare 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. ,
10CP each for B5, A4, and B4 sizes,
This is about one second before the 6CP and 4CP signals are generated, and therefore each count signal is used as a jam timing signal. That is, as shown in Figure 24-b, the A4C signal from terminal 258 is applied to one input terminal of two-input NAND gate 348, and the 6CP signal from terminal 240 is applied to the other input terminal. Therefore, the output of the gate 348 is an inverted 6CP signal and is applied to one input terminal of the three-input NAND gate 350 only in the case of A4 size copying. Also
In the case of B4 size copy, B4C and 4CP are input from terminals 257 and 239, respectively, and two input NAND
added to the input terminal of gate 349;
is applied to another input terminal of gate 350. In addition, the 10CP signal is transmitted to the inverter 34.
7 and is inverted and applied to the other input terminal of gate 350. 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.
10CP signal appears and in case of B5 size copy,
Only the 10CP signal appears and 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. (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. As shown in the figure. In the figure, P is an AC input power supply, PL ₁ , PL 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 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, regardless of whether the main switch is ON or OFF, RL ₁ receives a trigger signal until the specified sequence is completed.
Electricity can be applied by the occurrence of T ₁ . In this circuit example, RL ₁ includes the main motor, high voltage AC output, etc. Also, in RL ₂ , main switches S ₁ and S ₂
When turned on, a trigger voltage is applied to S ₂ and 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 is applied. 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 function. 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 the 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 generating 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 , thereby cutting off conduction to all loads and control circuits. 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 intensity illuminance lighting command signal generation circuit, FIG. 21a shows a post-rotation command signal generation circuit, and FIG. 22b is its time chart, FIG. 22a is the document table, forward and backward command signal generation circuit, FIG. 22b is its time chart,
Figure 23 shows the paper feed start command signal generation circuit,
4a shows a jam occurrence detection circuit, FIG. 24b shows a jam timing signal generation circuit, FIG. 24c shows their time chart, FIG. 25 shows a signal generation circuit for controlling conduction, and FIGS. Figure 26b is a circuit that switches conduction to each terminal, and 4
8A, 48B, 48C, 71, 72 are magnetic detection elements, 161, 162 are magnets, 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:
Document glass forward command signal, CBREV: Document glass backward command signal, B5C, A4C: Cassette size signal,
B5BP, B4BP: Original platen position detection signal, CBBP: Original platen reversal position signal, STOP: Reset signal.

Claims (1)

[Claims] 1. A rotating body having an endless photoreceptor that can form an image at any position, a reciprocating member for exposing and scanning a document to form an image on the rotating body, and transferring the image formed on the rotating body to a transfer material. means for transferring, means for generating a series of pulses, and means for moving the reciprocating member forward from a forward movement start position for exposure scanning;
a reciprocating means for returning the reciprocating member to the starting position after the forward movement is completed; and a driving signal is applied to the reciprocating means to reciprocate the reciprocating member that has returned to the starting position during a plurality of continuous copies. a storage means for outputting;
After the reciprocating member has returned to the forward movement start position, the storage means is set based on the pulse from the pulse generating means, and the forward movement means outputs a drive signal to generate an image from any position on the photoreceptor. A copying apparatus comprising a control means for starting formation.