JPH0480142A - Feeding in image forming device - Google Patents

Abstract

PURPOSE:To let a recording medium sucked to a transfer means stably and securely by using a belt where an alternating electric field is formed for an endless transfer means. CONSTITUTION:When an endless transfer means 53 gets in contact with a recording medium 77 with a relative speed zero, the recording medium is sucked as it is contained, it rises to a predetermined position, where it becomes possible to be fed. At this time, a relative deflection is not produced between the endless transfer means 53 and the recording medium 77. An alternating electric field pattern is formed at this transfer means 53 by a high voltage power source 131, so the recording medium 77 is sucked. The transfer means 53 thus sucks the uppermost one of the recording medium 77 in contact with it only, and the suction force is not applied to the second recording medium 77 on, thereby a double feed can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the feeding of recording media in image forming apparatuses such as copying machines, laser printers, and facsimiles.

[Prior art]

In image forming apparatuses such as copying machines, it is known that a sheet-like recording medium such as a transfer paper fed by the friction of a rubber roller is conveyed by a pair of rubber rollers or a belt to an image forming position such as a transfer position by a photoreceptor. ing.

In such conventional recording medium feeding and conveying devices, in order to prevent multiple sheets of recording media from being fed overlappingly, a friction pad is glued to the rubber feeding roller, and a rubber reverse roller is used to reverse the rotation. It is common practice to combine rollers, and to provide corner claws on the cassette that accommodates the recording medium.

However, the conventional recording method has problems such as jamming and skewing during conveyance, and in addition to double feeding, conventional apparatuses still have problems with the reliability of feeding and conveyance.

Furthermore, the structure becomes more complex and the control becomes more complicated.
It is also costly, and the problems of simplifying the device and reducing costs remain unsolved.

In order to solve these conventional problems, an insulating endless belt is passed around almost all the conveyance systems in the copying machine, and the belt is charged with a charging device, and the paper stored in the paper feed tray is transferred to the heald. The paper is fed by a paper feed roller installed coaxially with the support roll and is electrostatically attracted to the back heald, or the heald is directly brought into contact with the paper to electrostatically attract and feed the paper, and at the same time it contacts the photoreceptor. For example, Japanese Patent Laid-Open No. 59-212856 discloses that conveyance by a heddle to a transfer area to be transferred is carried out using a heald.
No., JP-A-59-224858, JP-A-59-229
This method has been proposed in Publication No. 585 and the like.

However, in these conventional technologies, when feeding the paper stored in the paper feed tray using a paper feed roller provided coaxially with the drive shaft of the insulating endless belt, the roller feeds the paper through frictional contact, so that the paper is not tilted. line occurred. In addition, when double feeding occurs, the first sheet of paper (upper side) is electrostatically attracted to the heddle and transported, but the second and subsequent sheets of paper (lower side) that are double fed with the first sheet are transported. It protrudes from the tip of the paper feed tray, causing a jam during the next feeding operation.

Furthermore, paper dust is generated due to frictional contact, resulting in poor paper feeding and poor image quality during image formation.

When the electrically charged insulating endless belt directly feeds the paper stored in the paper feed tray, the heald comes into contact with the paper in the rotational state during normal image formation, so it is difficult to tension the heald or hold it in place. The bottom state and paper loading state (loading state) are
Unless uniformity is achieved with considerable precision, the state of contact between the belt and the paper becomes unstable, which tends to cause the paper to skew.

Here, in order to stabilize the contact state between the belt and the paper, it is necessary to arrange both the heald and the paper within the apparatus with high precision.

Also, there is a certain amount of friction between the first sheet of paper (upper side) and the second sheet of paper (lower side) because the belt and roller contact the first sheet of paper in a rotating state. There was a risk that force would be generated and double feeding would occur.

Further, although the paper is not separated by friction, the rotating belt comes into contact with the paper, so a frictional force is generated, and a considerable amount of paper dust is generated.

Note that even if rollers or belts are used as paper feeding means, the state of paper being ejected from the paper feed tray is not always constant and reliable as described above, so the leading edge of the paper and the leading edge of the image to be copied on the paper may differ. It is necessary to provide a registration means for position adjustment and paper skew correction, and the structure and control are still complicated.

Also, the paper feed section, registration section, transfer section, fixing section, and paper ejection section of the copying machine are connected in this order with one endless belt, and the endless belt is first attached to the copy paper held in the copy paper feed section. For example, Japanese Patent Application Laid-Open No. 139846/1984 proposes that the copy paper be brought into pressure contact with the copy paper, and then carried out by frictional force from the copy paper feed section, and after registration, transported to an image forming head. However, with this conventional technology, when the heddle feeds out the paper stored in the copy paper feed section (paper feed tray), the roller separates and feeds the paper through frictional contact, resulting in skew or double feeding of the paper. In addition, paper dust was generated due to the frictional contact, resulting in poor paper feeding and poor image quality during image formation. In addition, since the state of paper feeding from the paper feed tray is not always constant and reliable, it is necessary to provide a registration means to adjust the position of the leading edge of the paper and the leading edge of the image to be copied on the paper, and to correct the skew of the paper. The structure and control were still complex.

[Problem to be solved by the invention]

The present invention solves the above-mentioned conventional problems and provides feeding x-1 of an image forming apparatus that prevents skew feeding, double feeding, and jam without requiring a registration means. The topic is

[Means to solve the problem]

The present invention solves the above problem in a feeding method for an image forming apparatus in which a recording medium accommodated in a storage means is fed to a predetermined position by an endless conveying means, in which at least a part of the endless conveying means is fed. A lowering step in which the storage means to be transported is lowered to the feeding position and stopped; a rising step in which the recording medium in the storage means is raised until it comes into contact with the endless conveyance means and then stopped; and a raising step in which the endless conveyance means is moved to a standby position. The image forming apparatus is characterized in that a return step in which the endless conveyance means ascends up to The problem was resolved using the pay difference method.

[Effect]

According to the present invention, the endless conveyance means carries out conveyance movement at a constant speed, and at this time, only a part of the endless conveyance means descends to the feeding position and brings the recording medium in the storage means into contact with the endless conveyance means. At that time, the endless conveying means moves additionally in the horizontal direction, and depending on the selection of the moving speed, the endless conveying means locally reduces the relative speed to a stationary member, such as a recording medium, or stops. or move it in the opposite direction.

When it comes into contact with the recording medium at a relative speed of zero, it becomes possible to suction the recording medium in its contained state, raise it to a predetermined position, and feed it. At this time, no relative deviation occurs between the endless conveyance means and the recording medium.

By forming an alternating electric field pattern on the conveyance means and configuring it to attract the recording medium, the conveyance means attracts only the topmost recording medium it comes into contact with, and does not attract the second and subsequent recording media. Double feeding was prevented because no adsorption force was applied.

〔Example〕

The details of the present invention will be explained based on embodiments shown in the drawings.

In FIG. 1, a copying machine 1 as an example of an image forming apparatus according to the present invention includes a scanner device 2 for reading an image of a document;
The copying main body 3 has a built-in image forming section that forms an image based on information from the scanner device, and a paper bank device 4 that stores a large number of recording media for recording images, such as recording paper. The scanner device 2 is placed on the bank device 3, and the scanner device 2 is placed on the copying main body 3.

The copying main body 3 has an image forming section 5 and a paper feeding device 6 in FIG.

As shown in FIGS. 1 and 3, the scanner device 2 placed on the copying body 3 may be constructed as an integral structure, as opposed to being formed as a side structure separate from the copying body 3. You can also do it.

The scanner device 2 includes a contact glass 1 on which a document is placed.
1, a document holder 12 for pressing and fixing a document against a contact glass 11, and an optical device. The optical device includes a lamp 13 for illuminating and scanning an original on a contact glass 11, a first mirror 14 that scans together with the lamp 13 and reflects light reflected from the original, and a first mirror 14 that reflects light reflected from the first mirror 14. It has a second mirror 15 and a third mirror 16 that sequentially reflect light, and a lens 17 that images the reflected light from the third mirror 16 onto the CCD 18. The second mirror 15 and the third mirror 16 are scanned at half the reading scanning speed of the lamp 13 .

The image forming section 5 built into the copying body 3 includes a writing optical device 7 . In FIGS. 2 and 4, the writing optical device 7 includes a semiconductor laser 21, a collimating lens 22 that converts the laser light emitted by the semiconductor laser 21 into a parallel light beam, and an aperture 23 that shapes the light beam into a light beam of a certain shape. and an unlinder lens 24 which makes the shaped beam from the aperture 23 enter the polygon mirror 25 in a compressed form in the sub-scanning direction. A polygon mirror 25 having an accurate polygonal shape is rotated in a constant direction at a constant speed by a polygon motor 26, and the incident laser beam is deflected by the rotation of the polygon mirror 25, and the deflected laser beam is passed through fθ lenses 27a, 27b, 27c.

The rotational speed of the polygon mirror 25 is determined by the speed, writing density, and number of surfaces of the image information holding means 31 of the image forming section 5, such as the photoreceptor 31.

The fθ lenses 27a, 27b, and 27c convert the scanning light with a constant angular velocity so that it scans the photoreceptor 31 at a constant speed, forms an image on the photoreceptor 31 so that it becomes the minimum light spot, and further tilts the surface of the photoreceptor 31. It has a correction function.

The light after passing through the fθ lens 27 (27a, 27b, 27c) is reflected by the mirror 28, and the light outside the image area is guided by the synchronization detection mirror 29 to the synchronization detection sensor 30, which outputs a cue signal in the main scanning direction. emit a signal. One line of image data is output based on the image information read by the scanner device 2 after a certain period of time after the synchronization signal is output from the synchronization detection sensor 30. The light as image data is reflected by the mirror 28 and forms an image on the photoreceptor 31 at the exposure position. By repeating this process, images are sequentially exposed onto the photoreceptor 31.

The photoreceptor 31 has a drum shape and has a photosensitive layer coated on its surface. An organic photoconductor (OPC) is used as a photoconductor sensitive to the wavelength of semiconductor laser 780 nm.1. α-3
i, 5e-Te, etc. are known, but in this example an organic photoreceptor is used.

Generally, in the case of laser writing, the light is applied to the image area.
P (negative/positive) process and P that shines light on the skin
There is a /P (positive-positive) process, and in this example, N
/P process.

The charger 32 uses a scorotron system having a grid on the photoreceptor side, and charges the surface of the photoreceptor 31 uniformly (-).
A laser beam is applied to the photosensitive area to lower the potential. As a result, -750 to -800■,
An electrostatic latent image of about -50V is formed in the image area. The electrostatic latent image is applied to the developing roller 33a by the developing device 33 at -500 to -
With a bias voltage of 600 .mu. applied, the (-) charged toner is developed and visualized.

The image visualized by the developing device 33 is transferred from the back side of the conveyor belt 53 onto a recording medium, such as a recording paper such as transfer paper, which is synchronously fed to the photoreceptor 31 by the conveyor heald 53 of the paper feeder 6. During transfer charging 34, a (±) charge is applied and the image is transferred.

Toner remaining on the photoreceptor without being transferred to the recording paper is scraped off from the photoreceptor 31 by the cleaning device 35 and collected in a tank within the cleaning device 35. Furthermore, the potential pattern remaining on the photoreceptor 31 is erased by applying light from the discharge lamp 36.

The reflection density on the surface of the photoreceptor is measured by a photosensor 37 provided at a position immediately after the development is performed by the developer 33. The photosensor 37 consists of a combination of a light receiving element and a light emitting element. To measure the reflection density, write a certain pattern (for example, a pure black or halftone dot pattern) using the writing optical device 7 at a position corresponding to the photosensor reading position, and then develop the reflectance of the pattern area and the exposure of the area other than the pattern area. It determines the density of the image based on the ratio of body reflectance, and if it is too light, it issues a toner replenishment signal. Furthermore, it is also possible to detect an insufficient amount of toner remaining by utilizing the fact that the density does not increase even after replenishment.

The recording paper on which the image has been transferred is separated by curvature by a drive roller 54 wrapped around a conveyor belt 53, and sent to a fixing device 38. The fixing device 38 includes a heat roller 39 and a pressure roller 40.
The toner on the surface of the recording paper is fixed by a pair of fixing rollers. After fixing, the recording paper is guided to a paper discharge path 42 by a claw 41 and discharged by a paper discharge roller 43 during normal image formation, for example, copying.

The paper feed device 6 has a transport device 51 and a receiving means, for example a paper feed tray or a paper feed center.

The conveying device 51 has an endless conveying means, for example, a conveying heald 53 that runs in endless circulation, and the conveying belt 53 has a driving roller 54, a first driven roller 55, a second driven roller 5
6 and adjustment roller 57 in sequence. The transport heald 53 is transported at a substantially constant speed by a drive roller 54. The conveyor belt 53 has a predetermined nip width between the drive roller 54 and the first driven roller 55, where the photoreceptor 31 contacts from the outside at an image forming position, for example, at a transfer position. A transfer charge medium 34 facing the photoreceptor 31 is disposed facing the inner surface of the conveyor belt 53.

Between the first driven roller 55 and the second driven roller 56,
A suitable number of pick-up rollers 58, for example two pink-up rollers 58, are arranged at suitable intervals inside the conveyor belt 53, and each pick-up roller 58 is formed to be able to move up and down. The interval between the pickup rollers 58 can be changed as needed by moving one or more pickup rollers.

The first driven roller 55 and the adjustment roller 57 are formed to be movable in a substantially horizontal direction, and the adjustment roller 57 is formed so as to receive the tension of a spring 59 so that a predetermined tension can always be applied to the conveyance heald 53.

As shown in FIGS. 5 and 6, the first driven roller 55 has shaft portions 55a at both ends rotatably supported by bearings 60, and the cough bearing 60 is slidable on a guide shaft 62 fixed to a side plate 61. It is formed as a supported slider. The shaft portion 55a may be fixed to a bearing 60, and the first driven roller 55 may be rotatably supported by the shaft portion 55a. The first driven roller 55 , that is, the bearing 60 is reciprocated along the guide shaft 62 by a moving device 63 . The moving device 63 performs additional movement of the conveying belt 53 in addition to the conveying movement by the drive roller 54, and is used as a feeding speed change device. The moving device 63 includes a drive shaft 6 rotatably supported by the side plate 61.
4, and a driven pulley 67 fixed to a driven shaft 66 rotatably supported by the side plate 61. The driving shaft 64 is rotationally driven by a moving motor 68. A drive belt 69 is wound around each drive boob IJ65 and driven pulley 67, and the drive heald 69 is attached to the slider 6.
0 by a fixing plate 70. The drive belt 69 is moved forward and backward by the forward and reverse rotation of the moving motor 68, and the slider 6
0 along the guide shaft 62, the first driven roller 55 is moved substantially horizontally.

When the first driven roller 55 is at the home position, which is the right end position in the figure, it is detected by the home sensor 71.

The adjusting roller 57 is also moved in accordance with the movement of the first driven roller 55, and is configured so that the conveying heald 53 can be maintained at a constant tension.

Therefore, the adjustment roller generally moves in the opposite direction to the first driven roller by a distance equal to the distance traveled by the first driven roller.

The moving speed V am /s of the first driven roller 55 is the conveying speed of the conveying belt 53, that is, the circumferential speed VllaI/S
1/2, that is, V = v / 2, then the first
When the driven roller 55 moves to the left in the figure, the conveyor belt 53 running in the direction of the arrow has a circumferential speed V in the section from the adjustment roller 57 to the first driven roller 55 via the second driven roller 56, that is, in the speed fluctuation region. Due to the effect of cabinet/S and moving speed V wm/s, the apparent upper conveyor belt 53
can be shifted to a stopped state and held in a stopped state. If the recording paper is sucked from the paper feed tray 52 during the stopped state in which the feeding speed indicated by the apparent speed above is zero, it becomes possible to feed the paper without using a registration device and without shifting the leading edge registration. In addition, the suction position is always the same, and there is no deviation due to belt conveyance, and there is no need for a registration stop operation by a specially provided registration device for image positioning. This means that it is only necessary to control the paper feeding timing and the image formation start timing.

In the speed fluctuation region that is a part of the conveyor belt 53 due to the movement of the first driven roller 55, a speed change operation is performed in which the conveyor belt 53 appears to stop at the top and then returns to a predetermined speed. The driving row 95 exits and passes through the transfer position.
4 to the adjustment roller 57, that is, in the constant speed region, the conveyor belt 53 does not appear to undergo any apparent speed fluctuations and moves at a constant speed. Therefore, the circumferential speed of the conveyor belt 53 remains unchanged while the recording paper is being transported to the transfer position and to the fixing position by the fixing device 38. This means that a part of the conveyor belt 53 appears to be in a stopped state with an upward speed change, and even while paper feeding is being performed, another recording paper is conveyed by the same conveyor heald 53, and transfer, separation, and fixing are performed. This can be done without any adverse effects. If the conveyor belt 53 is cleaned in a constant speed region in which it always runs at a constant speed, for example, by a belt cleaner 72 provided below the drive roller 54, cleaning defects will not occur.

When the conveyance heald 53 attracts the recording paper from the paper feed tray 52, the first driven roller 55 is moved to the right side in the figure and returned to the home position. At this time, the adjustment roller 57 is also moved.

When the first driven roller 55 returns to the home position,
The apparent speed in the speed variation region of the conveyor belt 55 increases to an upper speed, that is, the feeding speed increases to twice the speed in the constant speed region.

An upper presser roller 73 is disposed above the first driven roller 55 in FIG. 2, and a lower presser roller 74 is disposed on the lower right side of the first driven roller 55 in FIG. A guide plate 75 is provided between the presser rollers 74 and assists the conveyance of the recording paper conveyed by the conveyor belt 53 from the paper feed tray 52 so that the direction can be changed smoothly along the first driven roller 55. .

After the conveyor belt 53 is cleaned of dirt by a heald cleaner 72, a certain charge pattern is formed on the conveyor heald 53 by a charging roller 76 disposed near the heald cleaner 72. When a charge pattern is formed in the speed fluctuation area of the conveyor belt 53, as in the case where the charging roller 76 is disposed in circumferential contact with the second driven roller, the charge pattern is caused by the change in the feeding speed of the conveyor belt 53. A constant charge pattern can be formed on the conveyor belt 53 by performing control such as changing the frequency of the applied charges.

The paper feed tray 52 is a front-loading type recording paper stacking device, and the paper feed tray 52 is pulled out from the front of the copying machine 1, the recording paper 77 is placed therein, and the paper feed tray 52 is used for copying.
You can replenish recording paper by pushing it inside.

The paper feed tray 52 has a size series of recording paper (for example, A series,
B series, letter size, etc.). Although the A series will be explained here, the same applies to other series.

A center fence 78 is provided at the center of the paper feed tray 52, and a right fence 79 is provided on the right side, and the center fence 78 is collapsible as shown in FIG.

When setting A4 size recording paper, use the center fence 78.
7, and put them into the two tray chambers 80 and 81 formed on the left and right sides, respectively. , when printing A3 size paper, the space between the central fences 71 is opened and the recording paper is placed inside as one tray chamber.

On the lower side of the paper feed tray 52, a rising tray 8 is provided in each of tray chambers 8o and 8I formed on the left and right sides of the central fence 7B.
2 is provided.

When the central fence 78 is erected, the tray consisting of the tray chamber 80 on the right side and the rising tray 82 in FIG.
The tray configured by this is called a second tray 52#.

As shown in FIGS. 7 to 9, the central fence 78 has an upper face guide 83 and a lower face guide 84, and corner guides 85 are provided at both ends of the upper face guide 83 and at both ends of the lower face guide 84, respectively. This prevents the recording paper 77 from shifting laterally.

The upper face guide 83 is slidably inserted into the groove of the lower face guide 84, and the spring 86 is inserted into the groove of the lower face guide 84.
3 and the lower face guide 84. A groove is formed in the improved face guide 84 to improve the lower face guide F84.
can be inserted. Due to the action of the spring 86, the upper face guide 83 is maintained at a predetermined relative position with respect to the lower face guide 84 when no load is applied.

A notch 87 is provided at the center of the upper edge of the upper face guide 83.
is formed so that the operator's hand does not touch the recording paper 77 when setting it.

The lower face guide 84 is connected to the paper feed tray 52 by a support shaft 88.
It is rotatably supported by the frame. Lower face guide 84
It has an L-shaped finger portion 89 at its lower end. The lower face guide 8 is secured by the fingers 89 being locked to the protruding locking portions 9o formed on the frame 52a of the paper feed tray 52.
4 is stopped in a substantially vertical position when it is rotated and stands up, and is prevented from rotating any further. A claw 89a is formed on the finger portion 89, and a hook portion 9 formed on the frame portion 52a.
1, the lower face guide 84 is prevented from rotating in the direction of falling and is held in the upright position. Claw 89a
pushes the upper face guide 83 sideways with enough force to cause the hook 91 to come off due to elastic deformation, and the center fence 78 rotates clockwise in the figure and falls over, falling into the right tray compartment as shown in FIG. 80 and the left tray chamber 81 are opened.

When the center fence 78 falls, the upper face guide 83 and the lower face guide 84 are inserted into the recess 92 formed in the frame 52a of the paper feed tray 52 so as not to interfere with the recording paper placed on the rising tray 82. It is formed so that it is buried inside. The center fence 78 fell and the right tray room 8
0 and the left tray chamber 81 are in communication.
The claw 89a of the fallen lower face guide 84 is detected by pressing a switch 93 serving as a paper size sensor.

A paper end sensor 94 is provided on the upper surface of the rising tray 82 to detect the presence or absence of recording paper.

The central fence 78 can also be of a removable type instead of the retractable structure shown in the figure. Size detection at this time can be performed by providing a sensor that detects the presence or absence of the central fence 78.

The right fence 79 can also be formed by a lower face guide 84 and an upper face guide 83 in the same manner as shown in FIG. In this case, there is no need to overturn the right fence 79.

The conveyor belt 53 is transferred to the recording paper 77 in the paper feed tray 52.
One of the pickup rollers 58 that presses the pick-up roller 58 is placed directly above the upper face guide 83 of the intermediate fence 78, and the other one is placed directly above the upper face guide 83 of the right fence 79. Ru.

As shown in FIG. 10, one pickup roller 58 disposed directly above each face guide 83 and one or more other pickup rollers 58 are rotatably supported, for example, on a support plate 95 as a set. . In the illustrated example, two pickup rollers 58 are supported on the carrier plate 95 as a set, and each set of pickup rollers 58 is supported at the same height.

The support plate 95 is always pulled up to a fixed position by a tension spring 96, and the transport heald 53 is pulled up by the upper face guide 83.
It is located away from the top surface of. The support plate 95 rests against a push-down device 97, for example a cam device, by the force of a spring 96. From the time when paper is not fed as shown in FIG. 10, the support plate 95 is pushed down by the rotation of the cam 99 by the operation of the push-down device 97, and the pickup roller 58 is pushed down as shown in FIG.
one of them contacts the upper face guide 83 and pushes the upper face guide 83 down. The carrier plate 95 is pushed down until the conveyor belt 53 comes into contact with the recording paper 77 and is in a suction state.

As shown in FIG. 12, in the case of a cam device, the push-down device 97 has a paper feed cam 99 fixed to a shaft 98 at a predetermined interval and in the same posture. For example, as shown in FIG. 13, the paper feed cam 99 has an outer circumference of 144',
It is formed as a circular arc surface B with radius R3 from the center of the axis 98, for example, a radius of 10 degrees, and the remaining 216° range is divided into 108° increments, and the distribution is divided from the center point A to the radius Rz, for example from the center of the axis 98. Let the point be at the position 6■, and connect the arc surface B and the center point A with a smooth curved surface.

The shaft 98 is connected via a spring clutch 100 to a drive shaft 102 to which a pulley 101 is fixed. The pulley 101 is driven by a motor via a timing belt 103 and a speed reducer (not shown). A stopper 104 is fixed to the shaft 98. The stopper 104 is the first
As shown in Figure 4, there are two stepped portions 105.10 on the outer periphery.
The locking bar 107 is formed of a substantially spiral-shaped claw having a diameter of 6, and the claw of the locking bar 107 engages with one step 105 to prevent the stopper 104 from rotating. The locking bar 107 is connected to the support shaft 10
8, and is always held in a locked position with respect to the stepped portion 105 or 106 by a spring 109. A plunger of a paper feed solenoid 110 is connected to the locking bar 107, and when the solenoid is energized, the locking bar 107 is rotated around the support shaft 108 against the force of the spring 109, and the step is removed. The lock on the portion 105 or 106 is released.

When the stopper 104 is rotated, the angle from the first step portion 105 to the second step portion 106 is set to 120°, and when the stopper 104 is locked at the first step portion 105, the locking bar 107
When the locking of the stopper 104 is released, the stopper 104 rotates 120 degrees, the second step 106 locks with the locking bar 107, and the shaft 98
stop rotating. To be locked to the first stepped portion 105 -107
In the locked state, point A of the paper feed cam 99 is in contact with the support plate 95 as shown in FIG. 1O, and the support plate 95 is in the raised position.

The rotation of the pulley 101, which is driven by a motor (not shown) and transmits rotation of 120 rpm, is caused by the spring clutch 1.
00 to the stopper 104A: When paper is fed, the paper feed solenoid 110 is energized and the stopper 104 is released, and the stopper 10, which is always receiving rotational moment, is
4 started rotating because the lock was released, and 0.25 se
After c, the paper feed solenoid 110 is deenergized and the locking bar 10
7 comes into contact with the outer peripheral surface of the stopper 104 again. At this time, the stopper 104 has already made a half turn (180''), so the second step 106 has passed, and at the point when the stopper 104 has made one rotation, the claw of the locking bar 107 reaches the first step 10 of the stopper 1°4.
5 to stop the stopper 104. With this operation, the cam 99 rotates once every 0.5 seconds.The pick-up roller 58 moves together with the carrier plate 95.
Intestinal subnephropathy and 0.2secrj1 stop. At this time, as shown in FIG. 11, the arcuate surface B of the cam 99 is
The supporting plate 95 is pressed down. 0.2 seconds
After stopping for a while, it returns to its original position in 0.15 seconds. The pink-up roller 58 and a means for pushing down the pickup roller 58, such as a push-down crack [97] and a support plate 95, act as a suction actuation means for actuating the suction of the conveyor belt 53.

The gap between the transport heald 53 and the recording paper 77 in the non-feeding state is approximately 4 meters, and the gap with the upper face guide 83 is 2 meters.
It is. Therefore, when the pink up roller 58 moves downward, it descends two inches and comes into contact with the upper face kite 83.
Further, while pushing down the upper face guide 83, it descends by 2 m. At this lowered position, the conveyor belt 53 contacts the recording paper 77.

At this time, the recording paper 77 is stuck to the conveyor belt 53 by an uneven electric field caused by a charge pattern formed in advance on the outer peripheral surface of the conveyor belt 53 by the charging roller 76 . The rising tray 82 is formed and controlled so that immediately after the pickup roller 5B moves downward, the rising tray 82 rises until the contact pressure between the recording paper 77 and the conveyance belt 53 reaches a predetermined value of 4Ii, and then stops. . As a result, it is possible to correct the change in the upper surface position of the recording paper 77 caused by paper feeding, and the paper feeding position can always be maintained at the same height.

The conveyance belt 53 has a feeding function of feeding the recording paper from the paper feed tray 52, a conveyance function of conveying it to the transfer position, and a transfer function of contributing to the transfer to the recording paper at the transfer position.

Since the conveyor belt 53 attracts and feeds the recording paper using the attraction force generated by an unequal electric field instead of frictional force, there is no deviation of the recording paper, it has a registration function, there is no generation of paper dust during conveyance, and the power supply after transfer is reduced. There's no need.

The second stepped portion 106 of the stopper 104 is used when the paper feed tray 52 is replenished with recording paper, as will be described later.

As shown in FIGS. 2 and 15, rising trays 82 are individually arranged in a right tray chamber 80 and a left tray chamber 81, which are divided by the central fence 78 of the paper feed tray 52. As shown in FIG. 15 and FIG.
The wires 111 are fixed to the wires 111, respectively. The first wire 111a among the four wires 111 is connected to the first guide pulley 1.
12, it is turned by the second guide boob U 113 and its end is wrapped around the first drive pulley 114.

The first drive pulley 114 is fixed to a shaft 115 rotatably supported by the frame 52a of the paper feed tray 52. same first
One end of the second wire 111b is wound around the drive pulley 114, and the second wire 111b is turned and guided by the second guide pulley 113 along the way.

The third wire 111c and the fourth wire 111d, which are respectively fixed to the ascending tray 82 on the opposite side from the first wire 1lla and the second wire 11lb, are attached to a second driving pulley 116 whose ends are fixed to the shaft 115, respectively. It can be wrapped around. The third wire 111c, like the first wire 111a, is guided by the third guide pulley 117 and the fourth guide pulley 118 and wound around the second drive pulley 116, and the fourth wire 111d, like the second wire 111b, It is guided only by the four guide pulleys 118 and wound around the second drive pulley 116.

One end of the shaft 115 is connected to the output side of the electromagnetic clutch 119, and an encoder 120 is fixed to the other end. The input side of the electromagnetic clutch 119 is connected to a tray motor 122 via a force ring 121. The coupling 121 has a driving half 121a connected to the tray motor 122 side and a driven half 121b connected to the electromagnetic clutch 119 side.

The lifting tray 82 and the display device 123 are formed to have the same structure for both the right tray chamber 80 and the left tray chamber 81, but in the illustrated example, they are formed approximately symmetrically with respect to the center fence 78. Rising tray 82 for right tray chamber 80 and left tray chamber 8
The No. 1 lifting tray 82 can be driven by a separate tray motor 122. If it is necessary to distinguish between the right tray chamber 80 and the left tray chamber 81, the right tray chamber 80 and the left tray chamber 80 are distinguished by adding an A after the symbol and the left tray chamber by adding a B after the symbol.

The electromagnetic clutch 119 transmits drive only when the torque on the output side is less than a predetermined value in one direction of rotation, and slips and does not transmit drive when the torque on the output side is more than a predetermined value. There is.

As a result, the rising tray 82 on which the recording paper 77 is placed is raised by the rotation of the tray motor 1220, but when the top surface of the recording paper 77 comes into contact with the conveyance heald 53 and receives pressure, the slip action of the electromagnetic clutch 119 causes The rising tray 82 no longer rises, and the tray motor 122 stops after a predetermined period of time, so that the uppermost surface of the recording paper 77 is always maintained at a constant height.

When replenishing the recording paper 77, the paper feed tray 52 is pulled out from the front of the copying machine I. At this time, the drive half 121a of the coupling attached to the copying machine 1 side and the side of the paper feed tray 52 are pulled out. The driven half 121b of the coupling attached to the tray 82 comes off, and the rising tray 82 lowers to the lowest position under its own weight. At the same time, the tray open/close sensor 124 (FIG. 2) detects that the paper feed tray 52 has been pulled out.

After replenishing the recording paper 77, when the paper feed tray 52 is pushed into the copying machine 1, the drive half 121a of the coupling attached to the copying machine side and the driven half of the coupling attached to the paper feed tray side The bodies 121b are engaged, and at the same time, the tray opening/closing sensor 124 detects that the paper feed tray 52 is set.

The paper feed solenoid 110 operates to move the locking bar 107 to the first position.
When rotated clockwise in FIG. 4, the claw portion of the locking bar 107 is removed from the first step portion 105 of the stopper 104. The stopper 104, which has always been subjected to clockwise (rightward) rotational moment by the spring clutch 100, starts to rotate clockwise (rightward) because the regulating member is no longer present.

After 0, I see, the paper feed solenoid 110 is released and the locking bar 107 is again subjected to a counterclockwise rotational moment and comes into contact with the outer peripheral surface of the stopper 104. At this time, the stopper 104 has only rotated 115 times (72°), so it comes into contact with the outer circumferential surface between the first stepped portion 105 and the second stepped portion 106 .

When the stopper 104 rotates exactly 120 degrees, the locking bar 10
The claw portion 7 engages with the second stepped portion 106 of the stopper 104 and stops.

At this time, the B side of the cam 99 is in contact with the carrier plate 95 and is stopped, and the conveyance heald 53 is at the paper feeding position.

Next, the tray motor 122 is activated to raise the raising tray 82 together with the recording paper 77. When the top surface of the recording paper 77 comes into contact with the conveyor belt 53 and receives pressure, the electromagnetic brake 11
It is stopped by the action of 9.

After a predetermined time, the tray motor 122 stops. Then, the paper feed solenoid 110 is activated to rotate the locking bar 107 clockwise. Then, the claw portion of the locking bar 107 is removed from the second stepped portion 106 of the stopper 104. The stopper 104, which has always been subjected to clockwise (rightward) rotational moment by the spring clutch 100, starts rotating clockwise because the regulating member is no longer present.

After 0 and 1 see, the paper feed solenoid 110 is released and the locking bar 107 again rotates the motion member 10 in the counterclockwise direction.
7 hits the first stepped portion 105 of the stopper 104 again and stops. At this time, the conveyor belt 53 returns to its non-feeding position.

As described above, the first tray 52' and the second tray 52''
It is possible to replenish recording paper individually.

When the center fence 78 is folded down and A3 size recording paper is set in the paper feed tray 52 across the first tray 52' and the second tray 52#, the above-mentioned raising tray operation and cam operation are performed on the first tray 52' and the second tray 52'. , both are performed simultaneously on the second tray 52#.

This widens the contact area of the conveyor belt 53 during paper feeding, thereby stabilizing paper feeding and conveyance.

As mentioned above, during normal image formation, the recording paper fixed by the fixing device 38 in FIG.
1 to a paper ejection path 42, and ejected by a paper ejection roller 43. During double-sided copying, in which copies are made on both the front and back sides of the recording paper, the recording paper after fixing is reversed from front to back to the transfer position by the photoreceptor 31. It is necessary to feed paper to

For this reason, after the fixing device 38, the claw 41 allows the sheet discharge path 42 to be
A return guide path 44 is provided as a switchable branch path for guiding the recording paper to the paper feed tray 52.

The return guide path 44 and the reversing path 45 are provided as branching paths, and at the branching position, the path directly to the paper feed tray 52 and the reversing path 45 are provided.
The first switching claw 46a can switch between the passage and the passage.

The recording paper sent to the return guide path 44 is sent to the first switching claw 46a by the feed roller 47, and the recording paper guided to the reversing path 45 is nipped by the reversing roller 48 and sent to the rear end of the recording paper. When the reversal sensor 125 detects this, the reversing cola 48 reverses and is sent backward. The recording paper that is fed backwards is the second one.
The feed roller 4 of the return guide path 44 is controlled by the switching claw 46b.
9 and is discharged onto the paper feed tray 52.

Like A3 copy, the first tray 52' and the second tray 5
2# at the same time, after the paper feeding operation for front side copying, the tray motor 122 is reversed to lower the ascending tray 82 by a certain amount (the descending amount (movement amount) is memorized by an encoder (not shown)). After the recording paper 77 on which the front side has been copied is inserted into the paper feed tray 52, the ascending tray 82 is returned to its original position and the rear side copy feeding operation is performed.After the back side copy is completed, the recording paper 77 is ejected from the paper ejection path. Ru.

Like A4 copy, the first tray 52' and the second tray 5
2#, if front side copies are fed from the first tray 52', the tray motor 122 is
The ascending tray 82 of the second tray 52'' is lowered by a certain amount by reversing the direction (the descending amount (
Recording paper 7 with a copy on the front side to memorize the amount of movement)
After the recording paper 77 is inserted into the second tray 52#, the ascending tray 82 is returned to its original position, and the feeding operation for back side copying is performed.After the back side copying, the recording paper 77 is ejected from the paper ejection path.

On the other hand, when feeding the front side copy from the second tray 52'', after the front side copy feeding operation, the tray motor 122 is reversely rotated to lower the raising tray 82 of the second tray 52'' by a certain amount (using an encoder (not shown)). The lower ll!f(
After the recording paper 77 whose front surface has been copied is inserted into the second tray 5217, the ascending tray 82
is returned to its original position and a feeding operation for backside copying is performed, and after the backside copying, the recording paper 77 is ejected from the paper ejection path.

A recording paper upper limit sensor 126 is provided above the second tray 52'', and in the duplex image forming mode, even if you try to lower the ascending tray 82, when it is full of recording paper, the operation panel will not allow duplex copying. Display.

When you want to repeatedly form multiple images on the same side, such as composite copying instead of double-sided copying, the recording paper is moved to the reversing path 45.
The paper can be directly fed to the paper feed tray 52 by the first switching claw 46a without being guided by the paper feed tray 52.

In contrast to the automatic feeding of recording paper using the paper feed tray 52, there are cases where it is desired to manually feed the recording paper. For this reason, a manual paper feeder f130 is provided.

The manual paper feed device includes a manual feed door (not shown) provided in the machine frame of the copying body 3, guide plates 131 and 132 that guide the recording paper inserted through the core feed door, and a manual paper feed roller 133.

When the manual feed door is opened, the manual feed mode is switched to, and the first driven roller 55 is returned to the manual feed home position.
When the manual feed sensor 134 detects that the recording paper is present in the manual paper feed device 130, a manual feed clutch (not shown) is activated, and the rotation of the manual paper feed roller 133 transports the recording paper onto the conveyor belt 53.

The copying machine 1 has a minimum unit composed of a scanner device 2 and a copying body 3, and can function as a normal copying machine. In case of
For example, a paper bank bag 14 that can accommodate a paper feed tray or a paper feed cassette, and includes a tray that can accommodate a large number of recording sheets, is used. In this case, the copying body 3 is placed on the paper bank device 4 as shown in FIG.

The casing of the copying body 3 has a paper feed path 13 that is open at the bottom and guides the recording paper fed from the paper bank device 4.
6 is provided. The paper feed path 136 is formed to be able to feed the recording paper to a home position, for example, a dip position between the first driven roller 55 and the upper presser roller 74 located at the manual feed home position. A branch path 137 is provided in the paper feed path 136 so that the recording paper can be fed toward the first tray 52' of the paper feed tray 52, and a switching claw 138 is provided at the branch position to the branch path 137 to allow recording. It is possible to switch the paper feeding path. A paper bank paper feed sensor 139 is provided in the paper feed path 136 to detect that recording paper from the paper bank device 4 is fed. Paper banks are abbreviated as PB as necessary.

The paper bank device 4 has a 1st PB with a maximum loading capacity of 250 sheets.
It is equipped with a three-stage tray consisting of a )ray 201, a second PB tray 202, and a third PB tray 203, and a second IIPB tray 204 with a maximum loading capacity of 2000 sheets. Each PB
Paper feeding from the trays 201 to 204 is performed by one paper feeding conveyance device 205.

The paper feeding and conveying device 205 has an endless conveying means, for example, one endless belt 218, as shown in FIGS. 2 and 17. The endless heald 218 includes a driving roller 211 whose position is fixed, a tension roller 212 whose position is movable, a turning roller 213 whose position is fixed, a driven roller 2]4, a pink up roller 215, and a pair of belt speed change rollers 216. , and the auxiliary turning roller 217.

In FIGS. 17 to 19, guide rods 207 are provided almost vertically on the front side plate 205 and back side plate 206 of the paper bank bag W4, and the paper feed unit 220 is vertically slidably guided by the guide rod 207. be done. Paper feed unit 2
20 has a sheet feeding unit front side plate 222 and a sheet feeding unit rear side plate 223 to which a bearing 221 that is slidably mounted on a guide rod 207 is fixed. A driven roller 214, a pickup roller 215, and an auxiliary turning roller 217 are arranged so that both ends thereof are supported by the paper feeding unit front side plate 222 and the paper feeding unit rear side plate 223, respectively.

A pickup auxiliary roller 219 is disposed opposite to the driven roller 214 so as to press the conveyor belt, that is, the PB endless heald 218, and the paper feeding unit front plate 222
The sheet feeding unit is rotatably supported by the back side plate 223. The pink-up auxiliary roller 219 is used when changing the conveyance direction.
It serves to prevent the recording paper from peeling off from the heald 218.

A shaft 21 that rotatably supports the pink up roller 215
Both ends of 5a are movably supported in an elongated hole 224 formed in the front side plate 222 of the sheet feeding unit and an elongated hole 225 formed in the rear side plate 223 of the sheet feeding unit so as to be movable in a substantially horizontal direction. Further, both ends of the shaft 215a of the pickup roller 215 are fixed to the timing belt 226 by fixing fittings 227, respectively. The timing belt 226 is wound around a driving pulley 228 and a driven pulley 229, respectively. The drive pulley 228 is fixed to a common drive shaft 231 driven by a motor 230, and the drive shaft 231 is rotatably supported by the paper feeding unit front plate 222 and the paper feeding unit rear side plate 223. The driven pulleys 229 are rotatably supported by shafts individually attached to the paper feeding unit front side plate 222 and the paper feeding unit rear side plate 223, respectively. The pickup roller 215 is reciprocated along the long holes 224 and 225 by the forward and reverse rotation of the motor 230. Axis 21 of pickup roller 215
A home position feeler 232 and a bracket 234 for mounting an upper end detection sensor 233 for detecting the upper end of the recording paper are attached to 5a. When the home position feeler 232 activates the home position sensor 235 attached to the back side plate 223 of the paper feed unit, it is detected that the pink up roller 215 is at the home position. The upper end detection sensor 233 is the PB held 218
It detects when the paper feeding surface of the recording paper is at a height of five heights from the top edge of the recording paper, and feeds the paper from this position.

A lifting device 250 that moves the paper feeding unit 220 up and down is a motor 2 fixed to the back side plate 206 of the paper bank device.
51, and a drive shaft 25 rotatably supported by the back side plate 206 and the front side plate 205 and rotationally driven by the motor 251.
2, and two drive pulleys 2 fixed to the drive shaft 252.
53, a driven pulley 253 rotatably supported by the back side plate 206 and the front side plate 205, respectively, and two timing healds 254 wound around the drive pulley 252 and the driven pulley 253, respectively. The timing heald 254 is fixed to the front side plate 222 of the paper feed unit and the back side plate 223 of the paper feed unit, respectively, and when the timing held 254 is moved by the forward/reverse drive of the motor 251, the paper feed unit 71''2
20, that is, the paper feeding unit front side plate 222 and the paper feeding unit back side plate 223 are moved up and down.

Brackets 237 are respectively fixed to a front shaft 236a that is rotatably supported by the front side plate 222 of the paper feed unit, and a rear shaft 236b that is rotatably supported by the back side plate 223 of the paper feed unit. Both ends of a pair of heald speed change rollers 2]6 (216a, 216b) are supported. In other words, the first heald speed change roller 216a and the second belt speed change roller 216b are supported by a bracket 237, and are relative to the PB belt 218 that runs between both heald speed change rollers 216a and 216b by rotation of the shaft 236 (236a, 236b). Displace position. Inner shaft 2
36 (front shaft 236a and rear shaft 236b) is the rear shaft 236b
It is rotationally driven by a motor 238 connected to the motor 238. A feeler 239 is fixed to the rear shaft 236b, and the feeler 2
39 is the sensor 2 fixed to the back side plate 223 of the paper feed unit.
40, the home position of the belt speed change roller 216 is detected. Belt speed change roller 216
By rotating the shaft 236, a part of the PB belt 218 is transferred between the first belt speed change roller 2]6a and the second belt before the paper feeding operation.
Wrap it around the heald speed change roller 216b,
During the paper feeding operation, the PB belt is returned to its original position by rotating the shaft 236 in the opposite direction to return the PB heald 218, which is the winding, to control the feeding speed of the PB belt 218.

The transport of the PB belt 21B is driven by a transmission device having a gear 242 driven by a motor 241 attached to the back side plate 206, and a gear 244 that meshes with the gear 242 and is fixed to the shaft 243 of the drive roller 211. 2) This is done by rotating 1.

In order to grip and convey the recording paper, the PB heald 218 is provided with a charging roller to form a charge density pattern. In the illustrated example, the auxiliary turning port 217 is used as a charging roller, but it may be provided separately. An alternating current voltage, for example, ±2KVP-P, 26Hz, is applied to the charging roller 217 from the high-voltage electric fi 245 at a position before contacting the recording paper, and as a result, the surface of the PB belt 218 has a charge density of -
A striped charge density pattern in which σ and 10σ are alternately arranged at a period of, for example, 5fi is formed.

The paper feeding unit 220 feeds FBI-rays 201 to 2.
The adjustment roller 212 is moved in accordance with the movement of the driven roller 214 at that time, so that the tension is always maintained constant. Adjustment roller 212
The end portion supported by the front side plate 205 and the end portion supported by the back side plate 206 are respectively connected to a spring 247 via a wire 246, and are pulled in a direction to apply tension to the PB belt 218.

A first PB tray 20 is installed in the machine frame of the paper bank device 4.
1 to 4th PB) Opening/closing sensor 26 for each of the rays 204
1.262.263.264 are provided, and the opening and closing of each PB tray 201 to 204 is detected.

For example, the 1st PB as a small tray with a maximum loading capacity of 250 sheets.
) As shown in FIG. 20, the tray 201 to the third PB tray 203 have a side fence 265 for determining the position of the recording sheets to be loaded (explaining the first PB tray 201).
and an end fence 266. The side fence 265 and end fence 266 guide the recording paper in three directions. A fence may be provided at the front end in the paper feeding direction as long as it does not interfere with paper feeding.

The side fence 265 and the end fence 266 are movable in the direction of the arrow according to the size of the paper. P.B.
There is a handle 2 on the front wall of the tray 201 for easy loading and unloading.
67 may also be provided.

In Fig. 21, for example, the 4th PB) tray 204, which is a large tray with a maximum loading capacity of 2000 sheets, is the 1PB in Fig. 20.
) Similarly to the lei 201, a side fence 268, an end fence 269, and a handle 267 can be provided.

4th PB) Since the paper capacity of the tray 204 is large, it is preferable to form the side fence 268 in an L-shape so that the paper does not shift, and to guide the paper in the front, back, left, and right directions. The side fence 268 of the mold is shaped so as not to interfere with paper feeding.

The PB belt 53 in the copying body 3 attracts and conveys the recording paper with a charge density pattern formed by the charging roller 76.
In the paper bank device 4, a charge density pattern is formed on the PB belt 218 by an auxiliary turning roller 217 acting as a charging roller, and the recording paper is attracted and conveyed. For this reason, the conveyor belt 53 and the PB belt 218 are formed as endless belts having a dielectric layer 53a capable of holding charges on the surface layer and a semiconductor layer 53b on the back surface. At least one of the rollers supporting the conveyor belt 53.218, for example roller 56.215, is grounded and arranged in contact with the back side of the belt.

For example, as shown in FIG. 22, an alternating electric field (AHz) is applied to the charging rollers 76 and 217 (only the charging roller 76 is shown in the figure) from the high voltage power supply 131 as opposed to the grounding roller 56. The conveyor belt 53 is the drive roller 5
4, the position of the pickup roller that moves in the direction of the arrow at a constant speed of U/S and contacts and attracts the recording paper is downstream of the position of contact with the charging roller 76 in the direction of movement of the transport heald 53. There is. Therefore, the transport heald 5
3 is a high voltage power source 131 before the recording paper comes into contact with the surface.
An alternating current voltage is applied via the charging roller 76. As a result, the surface of the conveyor belt 53 has charge densities of −σ and +σ.
A striped charge density pattern is formed in which the charges are alternately arranged in U/A intervals. Charges of opposite polarity are induced in the semiconductor layer on the back surface of the transport heald 53 due to the charge density formed on the surface of the transport belt.

When a charge density pattern as shown in FIG. 22 is formed, unequal charges 132 are formed near the surface of the conveyor belt 53 as shown in FIG. The force acting on a unit volume of can also be determined using Maxwell's stress tensor. The recording paper 77 is electrostatically attracted to the conveyance heald 53 by the force Fχ in the direction perpendicular to the plane of the recording paper 77, that is, the plane of the belt, and is held without shifting.
The paper is fed and conveyed.

When the direction perpendicular to the sheet surface is x, the feeding direction is y, and the direction perpendicular to the feeding direction within the sheet surface is 2, the components of the force acting on the unit volume of the dielectric in the x, y, and z directions are F,,F,,
If it is F2, it will be as follows.

Maxwell's stress tensor hill, 8-cho(ε・hi) -include F〆p〆p EY
T) KEyOr4 (j・l EYC) ZE-29x
Et9y Shimauchi-Kei (F・p) Car f acting on unit volume, = Miyako (&D month (E-D')'y+2y (E*%)
? iz"xE'2.) This attraction principle differs from the commonly known force that attracts charges of opposite signs, and the above-mentioned method can be used to attract the recording paper without applying a valley charge to the recording paper. Therefore, even if it is used in a paper feed conveyance device of an electrostatic recording device, there will be no effect on the transfer process.

Although a stripe-like charge density pattern is shown as an example, a checkerboard pattern may also be used, and any appropriate pattern can be used.

As shown in Fig. 24, when A3 size plain paper is fed to the conveyor belt and the contact length reaches 100 m, a buff scale 133 is attached to the rear end of the paper, and the suction force is adjusted to the tensile strength. When measured as follows, the results shown in FIG. 25 were obtained. The adsorption area at this time was 300 CI''.

In Fig. 25, the amplitude of the AC voltage is constant, for example, 4KVP.
-P, and measured the adsorption force by changing the applied frequency.From this, in the present invention, the period of the stripe shape is 2.
Sufficient adsorption force was obtained when the range was 0 m + 10 W or less, especially 10 W or less. Further, as shown in FIG. 26, the adsorption force was measured by changing the applied voltage while keeping the applied frequency constant, for example, 26H2, and from the results, good adsorption force was obtained at 2KVP-P or more. Furthermore, it was found from measuring the surface potential that no charge density pattern was formed on the belt at the applied voltage at which no adsorption force was generated.

From this, in order to generate adsorption force, at least an applied voltage equal to or higher than the charging start voltage is required.

Further, the applied voltage is the same when a DC component is superimposed on an AC voltage, or when a non-uniform alternating voltage is applied from a power source that outputs a non-uniform alternating voltage.

FIG. 22 shows the belt configuration used in the paper feeding and conveying device of the present invention. The transport heald 53 is a two-layer type, with the surface layer being a dielectric film (polyester resin 20 μm, volume resistance 10'6 Ω・1), and the lower layer being a semiconductor layer (carbon dispersed in polyester resin 80 μm, volume resistance 10” Ω・C).
11), and is rotatably supported by a drive roller and a plurality of support rollers. The charging roller 76 receives ±2KV from the high voltage power supply 131.
An alternating voltage of 24H2 is applied. Further, the conveyor belt 53 is moved at a constant speed of 120 in the direction of the arrow by a drive roller.
■/S, and the paper feeding position of the recording paper is on the conveyor belt 53.
It is downstream of the contact position of the electrode of the charging roller 76 with respect to the moving direction of the charging roller 76 . Therefore, before the recording paper is fed to the surface of the conveyor belt 53, a charge density pattern is formed on the surface of the conveyor belt 53 at five cycles. Here, the reason why the volume resistance of the back surface of the conveyor belt 53 is set to 1011 Ω·1 is that if the transfer means is set on the back surface, the
This is because it had to be 0fΩ·1 or more. In addition, the above resistance was chosen because the adsorption force was greater when there was a difference in resistance with the surface layer. However, if the volume resistivity of the back surface is practically within the range of 10<7>Ω·Cm - 10<11>Ω·1, there will be no functional problem.

In FIG. 23, the PB belt 218 used in the paper feeding and conveying device of the paper bank device 4 of the present invention is a two-layer type, with the surface layer being a dielectric film (PET 50 μm) and the lower layer being an endless heald made of vapor-deposited aluminum. It is rotatably supported by a plurality of support rollers.

The volume resistance of this dielectric was set to 1016Ω1. The charging roller 217 is charged with ±2KV, 26Hz from the high voltage electric flB.
An alternating voltage of is applied. In addition, PB belt 218
is moved in the direction of the arrow at a constant speed of 130 cm/s by a driving roller, and the feeding position of the recording paper is downstream of the contact position of the electrode of the charging roller 217 with respect to the moving direction of the PB belt. Therefore, before the recording paper is fed onto the surface of the PB heald, a charge density pattern is formed on the surface of the PB heald at five cycles.

PB belt 2]8 in paper bank assembly W4 is the first
PB) Ray 201 to 4th PB) Recording paper is sucked and fed from the ray 204. For this purpose, the display device 250 is activated, and the paper feeding unit) 220 is
PB) Move up and down in front of Ray 203, 1st PB) Ray 2
It is stopped at the sheet feeding home position of the 01 to 3rd PB trays 203. In FIG. 17, the 4th PB) Ray 204
are arranged shifted from the 1st PB) ray 201 to the 3rd PB) ray 203, and the paper feed unit 220 is directly connected to the 4th PB)
It can be moved onto the recording paper in the tray, but the first
It is also possible to arrange it in the same line as the PB tray 201 to the third PB tray 203 and to move up and down in front of the fourth PB tray 204.

The paper feed home position for any PB) ray is a certain distance above the top edge of the recording paper, for example, 5 m above, and when the paper feed unit 220 moves to the paper feed home position of the selected PB) ray, the PB) Held 218
is located five cabinets above the top of the recording paper.

When the PB belt 218 contacts and suctions the recording paper to feed the paper, the relative speed of a portion of the PB belt, that is, the contact portion with the recording paper, relative to the recording paper is changed to almost zero.

In order to change the feeding speed of a portion of the PB belt 218, that is, the relative speed with respect to the static recording paper, a feeding speed changing means;
For example, a pair of belt speed change rollers 216 (216a and 2
16b) is used.

In FIG. 27, belt speed change rollers 216a, 216
For example, let b be a roller with a diameter of 8 cm, and let the distance between the centers of the belt speed change rollers 216a and 216b be 12 m,
The heald speed change roller 2 is driven by the motor 238 around the approximate center point between the axes of the belt speed change rollers 216a and 216b.
16a and 216b are rotated to wrap or unwind the PB belt 218 around the heald speed change rollers 216a and 216b. In FIG. 27, the PB belt shown in solid lines around the center 01 is rotated by an angle θ from the release position where the belt transmission rollers 216a, 216b are simply in contact.

When the PB belt 218 itself is not being conveyed, the amount of movement l of the PB heald caused by the rotation of the belt speed change rollers 216a and 216b by θ (rad)
1=2 rθ+12 (1-cos θ) where γ is the radius of the winding of the belt speed change rollers 216a and 216b.

From the relationship θ-ωL, the displacement speed V is expressed as a time derivative,
V=2γω+12ωsinωt. Here, ω is the rotational angular velocity.

When the PB belt 218 is moving at a constant speed of 130 m/sec and the paper feed unit 220 is descending at 150 m/sec, the contact area of the PB belt 218 with the recording paper is 2.
Since the PB belt 218 moves at a speed of 80 cm/sec, it is necessary to cancel this speed in order to stop the PB belt 218 in the contact area with the recording paper. For this purpose, by setting the displacement speed (2) to 280 m/sec, the angular velocity ω, that is, the driving speed of the motor 238 that rotates the shaft 236 is obtained.

In other words, in the case of the 1st PB) tray 201 to the 3rd PB tray 203, the paper feeding unit 220 moves at 150 m/sec from the paper feeding home position shown in FIG. 28A to the position where it contacts the recording paper shown in FIG. 28B. When the belt speed change roller 216 is lowered, the belt speed change roller 216 becomes the belt speed change roller 216a as shown in FIG. 28A.

The heald speed change rollers 216a and 216b are rotated in the direction in which the PB heald 218 is unwound from the PB heald 216b, for example clockwise in the figure. The portion of the PB belt 218 that contacts the recording paper is almost stationary, and the recording paper is electrostatically attracted by the charge density pattern of the PB belt 218.

Thereafter, the paper feeding unit 220 is returned to the paper feeding home position shown in FIG. 28C.

4th PB) In the case of the ray 204, the recording paper 7 is
7 is fed by suction. In the case of the fourth PB tray 204, the leading edge of the recording paper 77 is sucked away from the contact area of the PB belt 218, so if the recording paper is conveyed in this state, the recording paper will gradually separate from the PB belt starting from the leading edge. It will end up being put away.

Therefore, the PB belt 218 descends from the sheet feeding home position shown in FIG. 29 (A) to the position shown in FIG.
As shown in Figure C, while the paper feeding unit 220 rises and returns to the paper feeding home position, the leading edge of the recording paper is
14 by a certain amount.

For example, if the paper feed unit 220 is moved backward by 20 mm, the time it takes for the paper feed unit 220 to return to the paper feed home position is 5 (kaku)/150 (■/sec) = 0.033 (s).
ee), and the linear velocity of the PB belt 218 in the reverse direction is 20
(■) 10.033 (sec) = 600 (m/5
ec). PB belt 218 is l 30 m/se
Since the paper feed unit 22 is driven at a constant speed,
When 0 rises at 150 kaku/see, PB belt 21
At the contact surface of 8 with the recording paper, the winding of the belt speed change roller 216 is released and rotated so that it is returned at 600+130-150=580++w/see. Therefore, the above transition speed V is set to 580 kyo/se.
c to control the speed of motor 238.

PB held 218 in the paper feeding process for the next recording paper
In preparation for the deceleration of the recording paper contact N\i, the heald speed change roller 216 is rotated in the range between the adjacent recording papers being conveyed.

In contrast to the structure in which two rollers are rotated as in the example shown in FIGS. 27 to 29, as shown in FIGS. 30 and 31,
A structure having two fixed rollers 2/6' and one variable speed roller 216# disposed therebetween can be used. FIG. 30 shows an example used for the 1st PB) ray 210 to the 3rd PB) ray 203 as shown in FIG.
Figure L shows an example used for the 4th PB) ray 204 as shown in Figure 29. In the 30th example, the variable speed roller 216' moves to the paper feeding home position shown by the solid line, and while descending from that position to the position where it contacts the recording paper, it moves to the left in the figure and reaches the PB position.
The speed of the recording paper contact area of the heald is reduced or stopped, and the displacement roller 216' is displaced to the leftmost position in the figure at the position where the heald returns to the paper feeding home position.

In FIG. 31, a process of retracting the recording paper contact area of the PB heald in the opposite direction is added to the example of FIG. 30.

The paper feed unit 220 moves 150 degrees from the paper feed home position.
The time it takes to touch the recording paper after 5 strokes with Peng/see is 5 (m) /150 (Peng/sec> = 0.03
3 sec, PB belt 218 is 130
In order to counteract the uniform speed drive of the paper feed unit (Uniso) 22 (l) and the downward displacement due to the landing speed of 150 cm/sec, the roller 216 is displaced in the negative direction at 280 cm/sec.
Displace #. This displacement is performed for 0.033 seconds, so the amount of displacement is 280 (m/5ec) X Q, 033 (sec>
= 9.3 (m). For this purpose, displacement roller 2
16″ is 280 (m/5ec)/2 = 140
It is sufficient to uniformly drive it to the left in the figure by 9.3 (intestine)/2 = 4.7 (m) at a speed of (m/5ee).

In FIG. 31, since the leading edge of the recording paper is further transported backward to the position of the driven roller 214, the displacement roller 2]6' moves at a constant speed to the left in the figure at a speed of 290 cm/sec and a displacement amount of 9.7+a. drive

The speed change operation is performed until the axial center of the displacement roller 216'' moves to the left from the line connecting the axial centers of the fixed roller 216'.
In other words, a total displacement of 14.4 wn is performed by constant velocity control.

The electrical components of this copying machine will be explained.

In FIG. 32, the main control board 401 has an internal C.
It consists of PtJ, ROM, RAM, timer, I10 board, serial, etc. A one-chip CPU including these functions may be used. The main control board 401 performs overall soaking control.

The apparatus will be roughly divided into the copying main body side and the paper bank side.

First, the electrical system on the main body side will be explained. The main body side can be roughly divided by function: image creation related, 1st PB tray related,
2nd PB) Ray-related, duplex-related, transport-related, and other related matters.

First, other related matters will be explained. An operation display board 402 is capable of serial communication with the main control board so that commands or data can be exchanged. 2 is a scanner unit, and a scanner control board 408 transfers read image data and commands;
Sending and receiving data. Since the scanner section is not directly related to the present invention, a description thereof will be omitted.

Next, information related to image formation will be explained. 403 is a main motor, which drives the photoreceptor, fixing device, cleaner, and other driving rollers of the conveyance device, and 405 is a driver thereof. 406 is a fixing temperature controller for keeping the fixing temperature constant.

Image data read by the scanner is sent to the semiconductor laser 21, and its beam signal is transmitted in main scanning by the polygon motor 26 driven by the polygon motor driver 407. The synchronization detection sensor 30 is a sensor that determines the timing for writing image data.

The static elimination lamp 36 is a device that eliminates the potential of the photoreceptor. 41
0.409 is the developing motor and its driver. 37 is a photosensor that detects the standard pattern. 411 is a high-voltage power supply for the image forming system, and the charging corona, developing bias, transfer corona, and cleaning bias can be turned on/off individually.
It is now possible.

Next, electrical equipment related to the first tray 52' of the feeding tray 52 will be explained. ll0A is paper feed solenoid, 11
9A is a powder clutch, 122A, 415 is a PB) Ray motor and its driver, and a stepping motor is used as the motor. When the drive driver receives a pulse signal from the main control board, it excites the stepping motor in order to control the amount of movement using the number of pulses and the speed of movement using the pulse frequency. Further, in this example, the self-starting frequency region is used, but if the load torque is large, slow-up or slow-down control may be performed.

The encoder 120A is used to detect the remaining amount of paper, that is, the remaining amount of recording paper. 94A is a paper end sensor, which is a sensor that detects the presence or absence of recording paper on the first tray.

110B, 119B, 122B, 416.94B, 12
0B is an electrical system that performs paper feeding related operations for the second tray 52'', and has the same configuration and function as the first tray.

Next, transport related matters will be explained. Manual clutch 13
6 is driven during manual paper feeding to convey the recording paper. The manual feed sensor 134 is a sensor that detects the paper position during paper feeding.

Reference numeral 125.412 denotes a belt drive motor and its driver, which rotates the conveyor belt 53 at a constant speed. In this example, a stepping motor is used to perform the rotation operation in response to pulse signals from the main control board.

The registration sensor 135 detects the leading edge of the recording paper fed and conveyed by each tray 52', 52'', calculates the laser writing start timing from this, and turns on the ON10 F F of the other image forming system and double-sided conveyance system. It is designed to determine the timing.

Reference numeral 68 and 413 denote a roller moving drive motor and its driver, which, like the belt drive motor 125, rotates in response to pulse signals from the main control board. However, the pulse input to the driver in order to zero the feeding speed of the conveyance heald can be applied to the belt drive motor driver 412 by applying a pulse signal with a frequency of ]72 to bring the heald into a stopped state. I can do it.

Furthermore, the direction of roller movement can be controlled by a CW/CCW switching signal. In this case, the CW (clockwise) side is the direction when the belt is temporarily stopped, and the CC
The W (counterclockwise) side is the direction when retracting the roller to the home position.

The home sensor 71 is designed to detect the home position of the roller.

A high-voltage power source (A) 414 generates an AC high-voltage power source, and forms a positive and negative charge pattern on the belt by applying high voltage to the belt as the conveyor belt 53 moves. This charge pattern forms an unequal electric field, allowing the recording paper to be electrostatically attracted onto the belt. The attraction force of this positive and negative charge pattern depends on the pinch and the applied voltage level. The maximum suction force is obtained at a certain appropriate pitch interval, and paper is fed and conveyed in the region of this maximum suction force. That is, the application frequency at which the maximum adsorption force can be obtained is determined based on the belt speed. Furthermore, when the pitch interval is narrowed, that is, when the applied frequency is increased, there is a pitch interval at which the attraction force becomes zero, and this has the same effect as removing static electricity from the belt. This power supply is f/i1MJ through three signal lines, and is used to attract the recording paper, eliminate static on the heald, and switch the high voltage level for the cardboard.

Paper upper limit sensor 126, tray open/close sensor 124,
The paper size sensor 93 is related to the paper feed tray 52 or the first tray 52' and the second tray 52#.

Next, a description will be given regarding double-sided image formation. 417.4
18.125.420.419 is a double-sided noid 418 that switches between the first switching claw 46a and the second switching claw 46b. The reversal sensor 125 detects the presence or absence of recording paper during duplex operation, and activates the forward/reverse reversal motor 420 and its driver 419.
The timing of the forward and reverse signals given to the This forward/reverse reversal motor is formed by a motor that performs forward/reverse rotation at a linear speed faster than that of the image forming and transport system.

Reference numeral 421 denotes a replenishment solenoid for switching the switching claw 138 for replenishing the recording paper from the paper bank device 4 on the first tray 52'.

The paper bank paper feed sensor 139 detects the leading edge of the recording paper from the paper bank side, and thereby adjusts the ON10FF timing of each load on the main body side.

Next, the electrical system on the paper bank side will be explained in 241.
425 is a PB belt drive motor and its driver,
It has the function of conveying the recording paper to the main body side. Here, a stepping motor is used.

Reference numerals 251 and 422 are paper feeding unit drive motors and drivers, which perform the lifting and lowering operations of the paper feeding unit 220. 2
Reference numeral 56 denotes a paper feed unit position sensor, and position control is performed using this as a reference.

Reference numerals 230 and 423 denote a pickup drive motor and driver, which performs a recording paper pickup operation using a stepping motor. The pickup sensor (the home position sensor) 235 is a reference sensor for position control of the pickup roller.

238.424 is a PB belt variable speed motor and driver, which temporarily stops the belt in order to attract and hold the recording paper. 240 is a PB belt variable speed reference sensor that detects the reference position.

Reference numeral 233 is a paper top edge detection sensor, which shifts the position of the paper feed unit 220 with respect to the recording paper! do.

A high voltage source (B) 427 applies a high voltage to the PB belt in the same manner as the high voltage power source (A) to generate adsorption force to the recording paper.

426 is a paper size sensor, No. 1.2.3.4PB
Detects the paper size on the tray. 261.262.26
3.264 is a tray opening/closing sensor, which detects opening/closing of the PB) lay.

In the printer mode, this device is commanded by a control command from a host computer that sends print data. Meanwhile, equipped with a reading scanner,
When using it as a copying machine, use the input key to issue the command.
It requires an operation section with a mode indicator. The main input keys include the print and stop keys that support starting and stopping the copying machine, the 10 key that sets the number of copies, the auto density and density adjustment keys that adjust the copy density, and the magnification and zoom keys that specify the magnification. etc. Further, the operation section is constituted by an LCD panel that shows the input status, and the operation section 600 is a third
As shown in FIG. 3, it has an operation panel 601, in addition to the above-mentioned various keys (not shown), a page continuous copy key 603 for continuously copying a spread document such as a book onto two sheets of recording paper;
Duplex key 604 to copy on both sides of recording paper, continuous paper feed key 605 to feed recording paper continuously without paper gaps, lower stage PB
) A replenishment key 606 is provided for conveying the paper of the lay to the upper stage. Furthermore, when each mode is specified manually using the keys, the LCD 60 provided corresponding to each key will be displayed.
611 lights up from B.

Continuous page copying, double-sided printing, and continuous paper feeding mode are established independently, and 3
If both modes are specified, the continuous page continuous copy double-sided mode is used, and high-speed copying of book originals is performed. The replenishment mode transports and replenishes recording paper to the upper tray with a short transport path during a pre-specified time when the device is not operational, such as at night.This mode can be set manually or automatically. good. Further, the cardboard display 607 is turned on by manual operation of the cardboard key 602, and the paper feeding conditions (for example, charge pattern intensity, charge pattern area, etc.) from the paper feed tray and paper bank are changed.

The multi-stage paper feed of this device is displayed on the paper display section 613 of the LCD in the operation panel. The size of the recording paper stored in the paper feed tray of each stage is displayed on each size display 614 to 619.
The amount of paper remaining in each row is also displayed. In the figure, A4 size is selected for the fourth PB tray 619. In addition, by manual operation of the paper selection key 621,
The trays to be fed paper are sequentially selected, and the selected trays are displayed on the paper display section 613. On the other hand, the manual paper feed section 13
By opening the manual feed door of 0, the manual feed display 620
lights up, the paper is fed preferentially from the manual paper feed section 130, and
The selected tray display on the paper display section 613 is turned off.

The operation of this device will be explained based on a flow chart and a time chart.

In FIG. 34, after tfiON, initial settings are made and the roller movement initial operation is performed. This is an operation for retracting the first driven roller 55 to the home position. Then the third
The initial paper feeding operation is performed based on Figure 5.

After the initial paper feeding operation, if there is a mode change, a new mode is set. Mode changes are entered into the main control board as coded serial data by manual keystrokes on the operation display board. This causes a reception interrupt and determines the serial data. A flowchart of the reception interrupt is shown in FIG.

After the mode is set, it is determined whether the paper feeding initial operation needs to be performed again. The first case is when the paper feed tray is pulled out and the user manually replenishes the recording paper and then resets it, the second case is after the replenishment operation is completed, and the third case is when the duplex mode is set. In either case, by setting and resetting the flag, it is determined whether to return to step (3) and perform the initial paper feeding operation.

After that, size detection, heater temperature control, remaining amount detection, paper feed priority, bite voltage setting, replenishment processing, detection of the number of sheets that can be printed on both sides, detection of the number of sheets that can be printed on both sides of the page, various sensor inputs, and setting and resetting of flags accordingly. After executing a group of subroutines for non-pulse operation processing, a flag is used to determine whether or not the pudding SW has been pressed. If the pudding) SW is not pressed, return to the mode change process again.
Repeat the loop until SW is pressed. When the print switch is pressed, the pulse counter is reset and starts counting. The pulse counter here is a counter that counts up by a timer interrupt as shown in FIG.
An internal interrupt that occurs within the CPU at regular intervals.
The interrupt time is set by default.

After the count starts, the pulse table corresponding to each mode is entered and compared with the pulse count value. Here, the pulse table corresponding to each mode is a table of the number of pulses at 0N10FF timing of each load divided for each mode. If the table value and the counter value do not match, the process branches and executes the above-mentioned non-pulse operation process, and if the final copying process has not been completed, the process returns to (2) and is repeated thereafter. When the table value and the counter value match, the subroutine on the pulse table is executed, the pulse table is incremented, and processing outside the pulse operation is executed, and when the final copying process is completed, the process returns to (2) and repeats the loop.

In the initial paper feeding operation, as shown in FIG. 35, pulses are output from the main control board to the roller moving motor 68, belt drive motor, and their respective drivers. In this case, the number of pulses corresponding to the amount of movement and the pulse frequency corresponding to the speed of movement are set in advance.

Next, after turning on the paper feed solenoid 110, the paper feed timer counter is reset and starts counting. The paper feed counter is a counter that is incremented by the timer interrupt, and it is determined whether (1] seconds have elapsed from this count value, and the paper feed solenoid 110 is turned off after the elapse.

After that, the encoder timer counter is reset and starts counting.

This encoder is a drive shaft driven by the shaft of a tray motor 122 via a powder clutch 119]15
This is the sensor 120 attached to the. Then, after turning on the powder clutch, a pulse is output to the tray motor drive driver. The number of pulses at this time is 5
At the descending position 1 of the recording paper contact portion in step 3, it is sufficient to apply the number of pulses sufficient to cause the ascending tray 82 on which no recording paper is loaded to come into contact with the conveyor belt 53. Bye. After that, when the encoder interrupt shown in FIG. 38 does not come in, it is determined that the count has ended, and the counter value is stored in the RAM.
Hess door. This counter value is inversely proportional to the amount of recording paper remaining on the tray, and the remaining amount of recording paper can be detected based on this value. After outputting the pulse to the tray motor, set the paper feed solenoid 110 to 0N10 F F as above.
After outputting a pulse to the L, belt transfer U motor 68, switch the rotation direction of the belt transfer motor to, for example, CCW (counterclockwise), output a pulse again, retreat to the home position, and after detection by the home sensor 71, output a pulse. and terminate the process.

A timing chart showing the above operation is shown in FIG.

Note that the initial paper feeding operation is performed by the first tray 52' and the second tray 5.
2' are performed individually.

The transferred recording paper is transferred and fixed in a known manner.

Next, various operation modes will be explained.

[Continuous paper feeding mode]

In the continuous paper feeding mode, serial data indicating the continuous paper feeding mode is transmitted from the operation display board by inputting the continuous paper feeding key 605 on the operation unit shown in FIG. Upon receiving this, the main control board generates a reception interrupt (FIG. 36) and sets a continuous paper feed flag.

When the continuous paper feed flag is set, a new mode is set in the main flowchart shown in Fig. 34, and when the print switch is pressed, ON10 F F of each load is set according to the pulse table shown in the timing chart shown in Fig. 46. Execute sequence operations. Before explaining the timing chart, paper feed priority will be explained. This means that when recording paper of the same size, direction, and quality as the first tray 52' is selected, it is fed and transported with priority over the first tray 52', and the flow is the pulse operation of the main flowchart. Sent to external processing subroutines. The purpose of this is to shorten the first copy time and increase productivity. FIG. 39 shows a paper feed priority flowchart.

Next, the timing chart of the continuous copy mode shown in FIG. 45 will be explained.

When the print SW is pressed (step 1), the main, developing motor, charging corona, and cleaning bias (CL bias) are turned on (step 2). At the same time, a pulse is output to the belt drive motor (step 3), the conveyor belt 53 is driven, and the high-pressure iIt source (A) is turned on at the suction frequency.
N (step 4), and a charge density pattern is formed by the charging roller 26. After that, pulse output to the roller moving motor 6B (step 6), forward and reverse rotation in clockwise (CW) and counterclockwise (CCW) directions (step 7), and home sensor 7
1 detection (step 8), turning on the paper feed solenoid 110A (
Step 9) Turn on the powder clutch 119A (Step 10)
), pulse output to PB tray motor 122A (process 1
1), the paper feeding operation is performed. When using the first tray 52' and the second tray 52# at the same time, such as with A3 size recording paper, turn on the paper feed solenoid ll0B (step 1).
2), turning on the powder clutch 119B (step 13),
Pulse output to the tray motor 122B (step 14) is performed at the same time. The detailed timing chart of paper feeding operation is shown in the 46th page.
Shown in times.

In FIG. 46, pulses of rotation in the clockwise direction (CW force direction) are output to the roller moving motor 68. While this output is being performed, the belt is in a stopped state. The paper feed solenoid 110 is turned on in synchronization with the output, and the transport heald moves downward from the normal position to the lower kidney position in 0.15 seconds as shown in the downward movement diagram.

Thereafter, a pulse output is given to the tray motor 122 to press the recording paper against the conveyor belt 53 to adsorb it. At this time, the number of pulses given to the tray motor 122A is limited to the number of pulses given to the recording paper 122A because the tray has already been raised due to the initial paper feeding operation.
It is sufficient to give the number of pulses that has enough margin for the thickness of the sheet plus the pressing bone.

After paper feeding, the roller moving motor 68 is switched to the CCW direction to output pulses in order to retract the pickup roller to the home position, and the pickup roller returns to the home position detected by the home sensor 71.

In the case of continuous paper feeding, the paper feeding operation is started at the timing when the trailing edge of the fed recording paper passes the right fence 79 of the paper feeding tray, so that paper feeding and conveyance with substantially zero paper interval is performed.

Referring back to FIG. 46, after the sheet feeding operation is completed, the recording sheet is detected by the registration sensor (step 15). Based on this point, subsequent pulses are counted to determine the 0N10FF timing of each load. As a result, the 0N10FF timing of the writing gate, developing bias, and transfer corona is set, and image formation is performed (steps 16, 17, and 18). This is an example in which three sheets of paper are fed and conveyed and image formation is performed.

The adsorption OFF timing of the high voltage power supply (A) is OFF at the timing when the charge pattern is formed up to the rear end of the final recording paper.
The static elimination is turned on to eliminate the adsorbed charge pattern on the belt, thereby preventing the recording paper from being adsorbed outside the paper feeding operation, for example, during the initial paper feeding operation. For this reason, the machine is stopped either after the last recording paper is ejected to the outside of the machine or after static electricity has been removed from the suction area, whichever is longer.

[Page continuous shooting mode] FIG. 47 shows a timing chart of page continuous shooting mode.

The page continuous copying mode is a mode in which the paper feeding operations of the first tray 52''J7J2 tray 52'' are performed simultaneously, and two sheets of recording paper are simultaneously attracted and conveyed onto the conveyor belt to form an image. The timing chart shows an example in which this simultaneous sheet feeding operation is performed twice to form images on a total of four sheets.Similar to the continuous sheet feeding operation mode, a reception interrupt is generated by inputting the page continuous copy key from the operation unit, and the page A new mode is set by setting the continuous shooting flag.In FIG. 47, image formation is basically the same as the continuous paper feeding mode, and the only difference is that steps 9.10.11 regarding the first tray 52' and The paper feeding operation is performed by synchronizing the timing with similar steps 12, 13, and 14 regarding the second tray 52#.

That is, the paper feed solenoids 110A and 110B are operated in synchronization, the recording paper contact area of the conveyor belt 53 is lowered at the same time, and the ascending tray 82A of the first tray 52' and the ascending tray 82B of the second tray 52# are synchronized. The recording paper in the first tray 52' and the recording paper in the second tray 52'' are simultaneously attracted and conveyed.

Further, the timing of the next paper feeding operation may be set after the trailing edge of the recording paper fed by the second tray passes the right fence 79 where it contacts the leading edge of the recording paper of the first tray. Therefore, the timing is 0N10FF or detection timing as in step 6.7.8. In step 4.5, the timing is as shown in the figure because the recording paper area is attracted and static electricity is removed.

[Continuous paper feeding duplex mode]

In the continuous paper feeding duplex mode, after forming an image on the front side, the recording paper is reversed by the reversing device and temporarily stored on the second tray 52#, and after storing the same number of sheets on the second tray 52#, The problem is that there is unrecorded recording paper stored on the second tray 52''.Double-sided printing is possible based on this remaining amount. The number of sheets (number of sheets that can be stacked in the second tray 52'') is determined.

Remaining amount detection is performed in the main flowchart described above. Here, we will explain about the detection of the number of double-sided copies possible.
This will be explained using the flowchart shown in the figure.

In the main flowchart, when the double-sided flag is set, the paper feeding initial operation is performed as described above. Than this,
An encoder count value is set in RAM. This value is set to a on the first tray side and b on the second tray side. Detection of the number of sheets that can be printed on both sides is included in the subroutine group of non-pulse operation processing in the main flowchart. When executed,
First, the state of the double-sided flag is determined, and if no cent has been sent, the process is terminated. If it is set, the number C of sheets that can be double-sided is calculated based on the remaining amount of the second tray example.

This process may be performed sequentially by calculation, or by calling up the number of double-sided sheets for a value set in advance in a table. Next, it is determined whether or not the number of sheets to be placed is >C, and if YES, an error message is displayed on the operation display board, and a transmission is sent to display an instruction to set the number of sheets to be set to C or less. After that, after the print SW flag invalidation process (
In this state, even if you press the print switch, it will not start.)
Finish the process. When the user resets the number of sheets to C or less and performs the detection of the number of sheets that can be duplexed again, the number of sheets > C becomes No, sends an error display cancellation message to the operation display board, and executes SW flag enable processing. Finish the process.

When the print SW is pressed in this state, the operation is executed as shown in the timing chart of FIG. 48. When the print SW is pressed, step 2.3.4 is performed in the same way as in the continuous paper feeding mode shown in FIG. The difference is that the powder clutch 119B in step 13 is turned off and the ascending tray 82B of the second tray 52# is lowered.

This ensures a space for storing the recording paper on which the front surface image has been formed. The timing chart shown in FIG. 48 shows an example of two-sided continuous paper feeding. The paper feeding operations in steps 6 to 11 and the image formation related operations in steps 15 to 18 are the same as in the continuous paper feeding mode, so a description thereof will be omitted. Thereafter, when the leading edge of the recording paper on which the image has been formed leaves the fixing device 38, the double-sided switching solenoid is turned on (step 19), and the two successively fed recording papers are guided to the return path 44.

Next, the paper is conveyed to the reversing path 45 by rollers 47 . When the first sheet of recording paper is guided to the reversing roller 48, the forward/reverse reversing motor is already rotating at high speed in the forward/reverse direction (feeding side to the reversing tray 45a) (step 21), and the sheet is quickly fed by the reversing roller 4B. . Next, when the leading edge of the second sheet of recording paper is detected by the reversal sensor 125 (step 20), the forward/reverse reversal motor is reversed at high speed (step 21), and in synchronization with this, the reversal switching solenoid is turned on. (Step 22)
, the reverse rotation is performed until the rear end of the third recording sheet passes the reversing roller 48, and then the rotation is switched to the normal rotation.

In this way, the second recording paper is also guided onto the reversing PB tray, and if this is the final recording paper, a reversal operation is performed by the timer count, and the recording paper is stored in the second tray 52''. Here, (linear speed of reversing roller 48)>(
The relationship of (linear speed of roller 47) and (linear speed of reversing roller 48)=(linear speed of roller 49) is ensured.

This time, a paper feeding operation is performed from inside the second tray 52'' to form an image on the back side.The back side paper feeding operation is basically the same as the front side operation, but the difference is that the powder clutch 119B is turned on (step 13). At the same time, the pulse output (step 14) to the tray motor 122B is made to be the same as the number of pulses given in the initial paper feeding operation, so that the tray rises from the lowered position and the paper feeding operation can be performed.Subsequent back side image formation is the same as continuous paper feeding mode.

[Continuous page continuous shooting double-sided mode]

The continuous page continuous copy double-sided mode is selected from the page continuous copy key and the double-sided key 4 on the operation section 60Q4 in Figure 3. Similar to the book original, this mode forms images so that the front and back sides are in the same relationship. This is to copy pages 1 and 2 of a book manuscript by feeding and conveying two recording sheets in succession, copying the first page onto the first recording sheet, and copying the second page onto the next recording sheet. After copying, the first page is ejected as is, and the recording paper on which the second page is copied is reversed and stored in the second tray 52#.

The recording paper stored in this second tray 52' is fed to the back side to copy the third page of the original, and then new recording paper is continuously fed to copy the fourth page of the original. . The recording paper on which the third page has been copied is ejected as is, and the recording paper on which the fourth page has been copied is reversed and transferred to the second tray 52 in the same way as the second page.
Stored in #. Repeat this from now on. Therefore, in this mode, there is a limit to the number of sheets that can be placed. this is,
From paper feed port to transfer belt, return path, reversal path, second tray 5
The distance is determined by the number of sheets of recording paper on the conveyance path up to 2". In this example, the distance is 4 sheets for A4 and 2 sheets for A3, and the number of sheets to be placed is determined by this. In other words, Depending on the recording paper size, the possibility of continuous page copying for both apparatuses is detected.This is carried out according to the flowchart shown in FIG.

First, it is determined whether the page continuous copy duplex mode is entered using the flag, and after comparing the setting value of the number of f sheets depending on the recording paper size, if it is greater than the setting value, an error message is displayed and the number of sheets to be set is set to be less than the setting value. Display instructions.

If the set value is met, the display is canceled and the pudding switch is turned on. When the print switch is turned on, the operation is performed according to the timing chart shown in FIG. 49. Figure 49 shows the case where paper is fed and conveyed only from the second tray 52'', the first continuous recording paper is ejected, and the second
Steps 19.20.21. for loading into tray 52''.
The operations shown in 22 are performed. After that, the operation will be the same as in continuous duplex mode.

[Thick paper mode]

When the cardboard key is pressed on the operation unit, reception scraping occurs on the main control side. Here, the cardboard flag is set. Attraction voltage setting is performed in the pulse operation blue routine group of the main flowchart. A flowchart for setting the attraction voltage is shown in FIG. First, determine whether the cardboard flag is set and if it is set, turn on the signal line for switching the adsorption voltage of the voltage power supply (A).
The voltage level is set to a high voltage level suitable for absorbing cardboard. If the flag is not set, the signal line is OFF and has a high voltage level suitable for normal plain paper suction.

[Replenishment mode]

When the replenishment key is pressed from the operation unit, a reception interrupt is generated on the main control side. Here, a replenishment flag is set. Replenishment processing is performed in the blue routine group outside the pulse operation of the main flowchart. A flowchart of the replenishment process is shown in FIG. First, the number d of sheets to be replenished to the first tray 52' is calculated. After that, the replenishment solenoid is turned on and paper is fed from the paper bank side.

When the number of sheets actually fed exceeds d, the replenishment process is terminated.

[Receiving and passing the recording paper from the paper bank side] The receiving and passing of the recording paper from the paper bank to the main body side is carried out smoothly by making the conveyance speed of the conveyor belt and the PB belt equal, without any slack or tension. I can do it. For example, since the speed of the conveyor belt 53 on the main body side is 120 kg/sec, this can be achieved by setting the linear speed of the PB belt 218 to 120 kg/sec. However, in this example, in order to increase the productivity on the paper bank side, the PB heald line speed was set to 130 koms/se.
The case of c will be explained.

(PB belt linear speed)> (transport heddle linear speed), the first
When passing the recording paper from the PB belt 218 to the conveyor belt, the driven roller 55 is moved from left to right in the second pass, so that the conveyor belt and the recording paper come into contact with each other at an apparent upward position and with a relative speed of zero. death,! It adsorbs depending on the load pattern,
After being transported, the receiver completes the delivery. A timing chart showing this situation is shown in FIG. 50. When the recording paper is conveyed from the paper bank side, the paper bank paper feed sensor (PB paper feed sensor) 139 is ONL, and the receiver starts the transfer operation based on this. It will be done. Also, a pulse is output to the roller moving motor, and the roller moving motor is rotated forward and backward. This pulse frequency is the linear velocity difference between the conveyor belt and the PB belt of 10 km/5ec (130m/sec -120wm
It is sufficient to give the pulse frequency of the speed at which the roller moves in /sec). Further, the number of pulses at this time may be given as many as necessary to retreat to the home position detected by the home sensor. After retreating to the home position, a pulse is given on the CW side.

As a result, the recording paper and the conveyor heald come into contact with each other, and the paper is received and handed over. After that, the tip is detected by a registration sensor. This determines subsequent timing related to image formation.

In Figure 50, the two receivers show the timing of transfer. After the transfer is completed, the first receiver switches to CCW to return the moving roller to the initial position, and the number of pulses is the same as before. However, the carrier frequency is set to a somewhat higher frequency to increase productivity.

The first tray 52' and the second tray 52 in the copying main body 3
The paper feeding operations performed during various copying operations performed by feeding paper from '' are as described above. On the other hand, when the copying machine operates by feeding recording paper from the paper bank device 4, the procedure is as follows.

Paper bank 4 is 1st PB) Ray 201 to 4th PB
) The tray 204 is equipped with tray opening/closing sensors 261 to 634 that detect opening/closing of each tray. When the opening/closing operation of each PB tray is detected, it is assumed that the PB tray has been replenished with paper, and the following initial operation is performed.

For paper bank W4, each PB) Ray 201 to 204
is fixed in position, and one moving paper feeding unit 220 feeds paper from the corresponding PB) tray. Even if the remaining amount of paper on the FBI-ray changes due to feeding, the paper position according to the remaining amount of paper is memorized so that the paper feeding position, that is, the position of the topmost paper does not change, and the paper position is set to the paper feeding position. It is equipped with a high-speed PBI-ray change means to match the PBI-ray.

After detecting the opening and closing of each of the first PB tray 201 to the fourth PB tray 204, the paper feeding unit 220 is moved vertically by the paper bank UniSoto lift device drive motor 251 to the topmost point of the PB tray selected for paper feeding first. will be moved to Here, the top point of each PB tray is the first
PB tray 201 to 3rd PB) Ray 203 is loaded with a maximum number of 250 sheets, or 4th PB tray 204 is loaded with a maximum number of 2000 sheets at a height of about 5 feet above the 1st PB) rail and 3rd PB) tray. is located 30 meters from the bottom plate, and the fourth PB tray is located 205 inches from the bottom plate, and this position is taken as the home position of each PB tray. Further, the upper and lower home positions of the paper feeding unit 220 are the same as the home position of the first PB tray 201 at the top, and the position is controlled downward from there by the stepping motor according to the number of pulses. The vertical movement speed of the paper feed unit 220 at this time is, for example, 150.
■It moves up and down at a rate of 1/sec by forward and reverse rotation of the stepping motor. The paper feed unit 220 lands from the home position of each PB) until it is detected by the paper top edge detection sensor 233 provided in the paper feed unit 220, and the PB belt stops at a position five cabinets above the detected paper top edge. do.

Then, the paper feeding operation is repeated using this as the home position for the paper feeding operation.

Selection PB) Even if the lay is changed, the paper feed unit 22 is always
The paper feed position information of 0 is the main system as the amount of pulses from the stepping motor's home position? ! l-do 40
It is stored in non-volatile RAM within 1. This also allows the remaining amount of paper in each PB tray to be determined. Then, this position is set as the initial position at which the paper feeding unit 220 starts feeding paper next time. If it is selected again, the paper feed unit 22
0 is the point 5 points above the top of the stacked paper below the Baum position of the PB), and paper feed unit 2
The paper moves directly to the position detected by the paper top edge sensor attached to the paper tray 20, and repeats the paper feeding operation using that position as the home position of the paper feeding operation. This allows you to quickly (change the PB tray selection will be held.

Furthermore, when the paper is no longer detected by the paper top edge detection sensor 233 at the home position of the paper feeding operation during continuous paper feeding, the paper feed unit drive motor 251 feeds the paper until the paper is detected by the paper top edge detection sensor 233. unit 22
Move 0 downward and repeat paper feeding. As described above, as paper feeding progresses, the paper feeding unit 220 repeats the paper feeding process from the fixed PBI-ray while landing.

Flowchart G in FIG. 51 shows the paper feed selection operation.

PB consisting of paper selection) When a ray is selected, its P
Determine whether this is the first paper feeding after opening and closing the B tray. If this is your first time, the remaining amount of paper is not known and the paper feeding position is not fixed, so the top position B of each PB tray is used, and from the second time onwards, the paper loading amount is already known, so the last paper feeding home position is set. Using ffD as the target position χ of the paper feeding unit 220, it is compared with the current position of the paper feeding unit 220, and the paper feeding unit 220 is moved up and down.

Here, the pickup roller 215 is already inside the upper paper feed unit 220 in preparation for the vertical movement of the paper feed unit 220.

When the paper feeding unit 220 reaches the target position, the pickup roller 215 is moved in the paper direction in preparation for paper feeding. Next, the paper upper end detection sensor 233 detects the upper end of the paper, and the paper feeding unit 220 moves to the paper feeding home position.
to land. From the second time onward, this operation is not performed because the paper feed unit 220 has reached the last paper feed home position. At that time, the paper feeding home position is stored in the memory buffer D and used for the paper feeding operation. On the other hand, when the paper feeding unit 220 reaches the paper feeding home position, the print display is turned on and copying is started. Thereafter, the above-described second and subsequent operations are repeated during paper feeding, and the paper feeding unit 220 stores its position in the memory buffer D while landing.

The pickup roller 215 of the paper feed unit 220 picks up the paper in the PB tray by a certain amount, for example, 100cm, in the paper direction in order to attract the paper in the PB tray to the PB belt 218 during paper feeding.
It is displaced along with the bevel 218. On the other hand, when moving the paper feed unit 220 in the vertical direction due to paper selection, the pickup roller 215 is moved to the right to the home position and retracted. The movement of the pickup roller 215 is from the home position detected by the PB pick-up sensor 235 to the P
The PB pickup drive motor 230, which is operated by the B pink up drive motor 230, is a stepping motor, and its position is controlled according to the number of pulses.

Since the paper bank device 4 feeds paper from a fixed PB tray with a paper feeding unit 220 that moves up and down, the paper feeding position differs depending on the separate installation of the PB tray to feed paper and the amount of paper loaded. The transport timing from the paper feeding timing to the main body is calculated as follows.

The PB belt 218 is conveyed at a constant speed of 130 cm/sec by the PB heald drive motor 241, which is a stepping motor, and the paper after the operation of the PB belt variable speed motor 238 is 1
It is transported at a rate of 30 km/sec. The conveyance distance changes depending on the vertical position of the paper feeding unit, and is determined by the number of steps N of the paper feeding unit drive motor 251 from the home position. Since the feed unit drive motor 251 moves up by 0.2 in one step, the transport path L of each PB) ray is L.
= N X O, 2+ P . Here, P is a fixed distance by PB) ray, 1st PB) rail, 3rd PB) ray, 200 kaku,
For the fourth PB tray, the number is 120, and this difference is due to the horizontal conveyance distance. Therefore, the transport time T is expressed as T=L/130. The sum of the conveyance time T and paper feeding time is the time required to feed the first sheet, and continuous sheet feeding from the second sheet onwards is independent of the conveyance time. Furthermore, the paper feeding interval for continuous paper feeding is such that the paper feeding operation can be repeated at regular intervals, and printing of A4 size paper at 20 PPM can be performed repeatedly at 3 seconds/cycle.

The paper feeding operation will be explained based on the operation transition diagrams shown in FIGS. 28 and 29. Here, an example is shown in which the PB belt 2180 deceleration and stop mechanism uses two belt speed change rollers 216a and 216b. In addition, FIG. 28 shows the first PB tray 201~
In the case of paper feeding from the third PB tray 203, FIG.
4th PB) This is the case of paper feeding from the ray 204.

The paper feed unit 220 is located at the top 5■ of the stacked paper below the home position of the PB) ray, and is detected by the paper top edge sensor 223 attached to the paper feed unit 220! The paper feeding operation is repeated with this as the home position for the paper feeding operation. At this time, the pick unroller 215 and
The flat portion of the PB belt 218 stretched between the pickup roller 215 and the driven roller 214 is located 5 m above the upper end of the paper stack. Next, the pickup roller 215 of the paper feeding unit) 220 moves 100 degrees in the paper direction in order to adsorb the paper in the PB) lay to the PB belt 218 during paper feeding.
The PB belt 218 is displaced along with the PB belt 218.

PB) In order to attract the topmost sheet of the lay to the PB belt 218, prior to sheet feeding, a charging roller 217 forms a charge pattern on the PB belt 218 in an amount corresponding to the sheet size in synchronization with the sheet feeding timing.

The paper feed unit 220 is lowered to bring the PB heald 218 into contact with the upper end of the paper. At this time, the aforementioned heald speed change roller 216 is used to operate so that the feeding speed of the PB belt 218 on the sheet contact surface is zero. This is done to improve the suction ability so that only the topmost recording paper of the stopped paper is attracted and transported.
It is also possible to reduce the conveyance speed of the belt 218 to a speed of 130 sec or less, bring it into contact, and carry it by suction.

When feeding paper from the 1st PB tray 201 to 3rd PB tray 203, the paper, that is, the recording paper, is attracted from the leading edge.
A belt speed change roller 21 is used to convey the paper in the horizontal direction.
6 is used to raise the paper feed unit 220 to the home position of the paper feed operation at a point 5 mm above the paper while keeping the feeding speed of the PB heald 218 on the paper contact surface at zero.

Thereafter, the curvature caused by the heald speed change roller 216 is released, and the P
The paper is conveyed by making the vertical conveyance movement portion of the B heddle 218 a straight line. At this time, the sheet is attracted to the PB belt 218, which is driven at a constant speed of 130 wrr/sec by the PB heald drive motor 241, and is conveyed at a constant speed.

The winding means of the heald variable speed roller is operated between the continuously fed sheets where the conveyed paper passes the belt speed change roller 216 to prepare for deceleration in the next paper feeding process. At this time, the PB heald 218 on the paper feeding surface is accelerated, but it is not in contact with the paper and there is no problem.

On the other hand, when paper is fed from the fourth PB tray 204, the paper is attracted from a position approximately 20 degrees from the leading edge, and the driven roller 204
In step 14, in order to convey the paper vertically, the belt speed change roller 216 is used to first convey the paper horizontally to the left. That is, while the feeding speed of the paper contact area of the PB belt 21B is set to negative (moves in the opposite direction), the upper paper 5
By raising the paper feeding unit 220 to the home position of the paper feeding operation at point (2) above 0, the paper feed and conveyance are stabilized because the paper is attracted to the PB belt 21B up to the leading edge of the paper in the 4th PB tray 2 (also in the case of 14). You can do it.

The PB heald speed change motor 238 that rotates the heald speed change roller 21-6 is composed of a stevening motor, and a timer value corresponding to the driving speed of the PB belt speed change motor 238 for each time in the held speed change operation determined as described above is set. is stored in the ROM in the main control board 401 in advance, and the speed control and forward/reverse control of the PB heald variable speed motor 238 are performed while recalling it.

On the other hand, in preparation for deceleration in the next paper feeding process, the winding operation of the belt speed change mechanism between sheets of continuous feeding when the conveyed paper passes through the belt speed change roller 216 is normally performed with a paper distance of about 150 m for A4 size. For certain reasons, the PB belt motor 238 may perform winding operation at a constant speed.

The paper feeding operation in the 1st FB tray 201 to the 3rd PB tray 203 is carried out according to the timing chart shown in FIG. 52, for example, and the paper feeding operation in the 4th PB tray 204 is carried out in accordance with the timing chart shown in FIG. 53, for example. . FIG. 52 shows an example of feeding A3 size recording paper, and FIG. 53 shows an example of feeding A4 horizontal size recording paper.

In FIG. 52, the PB belt drive motor 241 is turned on.
Rotate at a constant speed. Next, high-voltage electricity #B that applies voltage to the charging roller 217 is operated in accordance with the paper feeding timing. This start timing is programmed in advance with a value calculated from the linear velocity as the position at which the charge pattern of the PB heald 218 is formed so that the charge pattern is formed upstream of the position at which the PB heald 218 is attracted.
In this example, this value is about 1-48 seconds before the biting operation, and this time differs only in the 4th PB) ray 204.

Next, prior to the paper feeding operation, the PB belt variable speed motor 238 is rotated in the forward direction, and the heald variable speed roller 216 or the displacement roller 2
Move #16 and keep it on standby.

At the paper feeding timing, the paper feeding unit drive motor 25
1 is rotated in the forward direction, and at the same time, the PB heald variable speed motor 238 is rotated in the reverse direction at a high speed to bring the PB belt 218 into contact with the upper surface of the paper, with the head loading speed of the paper feeding suction surface of the PB held 2 and 8 set to zero. Moreover, the PB heald speed change motor 238 is further reversed to retract the heald speed change roller 216 or displacement roller 216# to the left, and the PB belt 218 is conveyed vertically. The paper being fed and conveyed is detected for approximately 3.2 seconds by a PB paper feed sensor 139 provided in the paper feed path of the main body. High pressure′
@ Source (B) 427's operation end timing is the same as when constant speed operation is performed due to the acceleration and deceleration operation of PB heald 218 during the continuous operation period, and 3.2
Operates only for a period of sec. Also, when the linear velocity of the PB heald 218 at the charge pattern formation position changes, that is,
When the PB heald variable speed motor 238 is operating, the PB heald 2
A high voltage power supply (
B) Change the applied frequency by 427. Since the last formed charge pattern becomes effective, when the linear velocity of the PB belt 218 at the charge pattern forming position is less than zero, the high voltage B
(B) The operation of 421 is arbitrary and is 0FFf in this example.

In FIG. 53, the basic operation is the same as in FIG. 52. The fourth PB) lay 204 includes a displacement operation of the suction surface of the PB belt 218 in the negative direction in order to suction the paper to the leading edge of the paper to the PB held 21B.
8 at higher speed, paper feed surface linear speed -600wa/
sec. The operation timing of the high-voltage power supply (B) 427 is different from other PB) rays in layout, so it is activated approximately 1.98 seconds before adsorption, and because it is A4 size, the PB heald 218 at the charge pattern formation position moves at high speed. It stops working during the operation.

As a result of the above, the PB belt 21 has a length equal to the paper size.
The PB heald 218 can be attracted to the charge pattern forming position No. 8 in a stopped state and transported.

As the suction device, in addition to the method using the charge pattern described above, it is also possible to use an ordinary vacuum suction device depending on the case.

〔effect〕

According to the present invention, skewing during feeding and conveyance of a recording medium can be prevented without providing a registration means, and
Furthermore, double feeding is no longer caused, and a feeding and conveying device with extremely high conveyance reliability without occurrence of jams has been obtained.

According to the present invention, it is possible to reduce the frictional force exerted on the recording medium by the conveying means to zero or as much as possible, thereby suppressing the generation of paper dust, resulting in poor conveyance of the recording medium due to paper dust and poor image quality during image formation. A feeding and conveying device with extremely high reliability was obtained.

According to the present invention, the feeding state of the recording medium from the storage means is always constant and reliable, and there is no need for a special recording medium conveyance state adjustment device or recording medium conveyance means in addition to the conveyance means, and the structure is simple. A low-cost feeding and conveying device was obtained.

According to the present invention, a constant and reliable transfer from the storage means is always carried out without changing the entire endless transport movement speed from feeding from the storage means to the image forming section, and therefore without reducing the copy production speed per unit time. A feeding and conveying device capable of feeding was obtained.

When a belt on which an alternating electric field is formed is used as the endless conveyance means, it becomes possible to stably and reliably attract the recording medium to the conveyance means, and there is no need to provide a special registration device.

By performing the return movement after the trailing end of the paper feed medium has passed through the additional movement device, it is possible to prevent external force from being applied to the recording medium during conveyance, and to reliably prevent all skew jams.

[Brief explanation of drawings]

1 is an overall perspective view of an example of an image forming apparatus according to the present invention, FIG. 2 is a schematic front view, FIG. 3 is a schematic view of a scanner device, and FIG. 4 is a plan view of a writing optical device. FIG. 5 is a plan view of the conveyance means transmission, FIG. 6 is a perspective view of the conveyance means transmission, FIG. 7 is a front sectional view of a part of the storage means, and FIG.
7 is a front sectional view showing the partition means in a tilted state; FIG. 9 is a perspective view of the partition means; and FIG. Schematic drawings, FIG. 11 is a diagram corresponding to FIG. 10 showing the operating state of the conveyance means pressing device, 12th is a perspective view showing the drive system of the conveyance means pressing device, FIG. 13 is a front view of the cam, 14th The figure is an explanatory diagram of the stopper of the drive system of the conveying means pressing device, the first
5 is an overall perspective view of the storage means, FIG. 16 is a perspective view showing the drive system of the raising tray of the storage means, No. 1711 is a schematic front view of the paper bank device, and FIG. 18 is a perspective view of the paper feeding unit. Figure 19 is a plan view of the paper feed unit, No. 2011Z
21 is a perspective view of another example of the storage means, FIG. 22 is a perspective view illustrating the formation of an alternating electric field on the conveying means, and FIG. 23 is a front view illustrating the formation of the alternating electric field. , second
4th is an explanatory diagram of the method of testing the attraction force using an alternating electric field, Figure 25 is a diagram showing the relationship between the pitch of the alternating electric field and the tensile force indicating the attraction force, and Figure 26 is a diagram showing the relationship between the applied voltage of the alternating electric field and the tensile force. FIG. 27 is an explanatory diagram of another example of the conveyance means transmission; FIG. 28 is an operation diagram showing the operating states of the conveyance means transmission according to FIG. 27 by A, B, and C; Fig. 29 shows the 28th example in which the relative positions of the conveyance means and the storage means are different.
FIG. 30 is an explanatory diagram of another example of the conveying means transmission, FIG. 31 is a diagram corresponding to FIG. 30 of an example in which the speed change step is modified from FIG. 30, and FIG. 32 is a diagram corresponding to FIG. is a block diagram of the electrical system of the control device, FIG. 33 is a partial diagram of the operating section, FIGS. 34 to 43 are flowcharts, FIGS. 44 to 50 are time charts, and FIG. The control flowchart of the paper bank device, FIGS. 52 and 53, are time charts for the control shown in FIG. 51. 52...Accommodating means 55...Followed roller 77...Recording paper 202...Accommodating means 204...Accommodating means 216...Additional moving means 53...Endless conveying means 63...Additional Moving device 201... Accommodating means 203... Accommodating means 218... Endless conveyance means 3 Fig. 4 Fig. 5 Fig. 7 Fig. 8 Fig. 13 Fig. 14 Fig. 25 Fig. 26 Kaloman = [niVp P] Procedural Amendment, Kayo, &1 November 26, 1990

Claims (2)

[Claims] (1) In a feeding method of an image forming apparatus in which a recording medium accommodated in a storage means is fed to a predetermined position by an endless conveyance means, at least a part of the endless conveyance means is to be fed. a lowering step in which the recording medium in the storage means is raised until it comes into contact with the endless conveyance means and then stopped; a return step in which the endless conveyance means is raised to a standby position. A feeding method for an image forming apparatus, characterized in that: a charge density pattern is formed by a charging device until the endless conveying means reaches a feeding position in the lowering step. (2) When the accommodating means is pulled out from the apparatus main body and later stowed, when the accommodating means is refilled with recording media, when the apparatus main body is powered on, or when double-sided copy mode is set. 2. The method of feeding an image forming apparatus according to claim 1, wherein in any one of the above cases, the lowering step, the raising step, and the return step are performed while the charging device is inactive.