JPH0480144A - Image forming device feeding device - Google Patents

Abstract

PURPOSE:To stabilize the cleaning performance, and prevent uneven abrasion by providing a cleaning means for cleaning an endless transfer means at a constant speed motion part of the endless transfer means. CONSTITUTION:For an endless transfer means 53, its surface where it gets in contact with a recording medium 77 is cleaned by a cleaning means 72. At this time, the cleaning means 72 is disposed to be applied to the endless transfer means 53 at a constant speed motion part, so the applied part of the cleaning means 72 is applied to the transfer means 53 in constant motion conditions constantly. Effects of a speed change are not given to the cleaning means 72 if a speed changing action is given to the transfer means 53 which is capable of speed change for changing the speed at a part where the transfer means 53 supplies the recording mediums 77 from the containing means 52. Cleaning defectives or uneven abrasion are thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording medium feeding device in an image forming apparatus such as a copying machine, a laser printer, or a facsimile machine.

[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 combined with the rubber feeding roller, and a rubber reverse roller is used to reverse the rotation. In addition, corner claws are provided on the cassette that houses the recording medium.

However, the conventional recording system has problems such as jams 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 belt. The paper is sent out by a paper feed roller installed coaxially with the support roll and is electrostatically attracted to the rear belt, or the belt is brought into direct contact with the paper and electrostatically adsorbed and fed, and at the same time, the paper is brought into contact with the photoreceptor. For example, it is known in Japanese Patent Application Laid-Open No. 59-212856 that conveying by belt to the transfer area N where the transfer is performed is carried out using a belt.
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. Also, when double feeding occurs, the first sheet of paper (upper side) is electrostatically attracted to the belt and transported, but the second and subsequent sheets of paper (lower side) that are double fed with the first sheet are not fed. It protrudes from the edge of the paper 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 belt comes into contact with the paper in the rotating state during normal image formation, so the tension of the belt and the The status and paper loading status (loading status)
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 heald and the paper, both the belt and the paper must be placed 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 there, 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 copied onto the paper cannot be kept constant. It is necessary to provide a registration means to adjust the position of the paper and correct the skew of the paper, 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 by friction force, and then transported to an image forming area after registration. However, in this conventional technology, when the belt feeds the paper stored in the copy paper feed section (paper feed tray), the roller separates and feeds the paper through frictional contact, resulting in skewed paper feeding and electric feeding. Furthermore, paper dust is generated due to 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, prevents skew feeding, double feeding, and jam without requiring a registration means, and prevents poor cleaning and uneven wear of the cleaning means for cleaning the conveying means. tJN refers to the provision of a feeding device for an image forming apparatus.

[Means to solve the problem]

The present invention solves the above-mentioned problems in a paper feeding device for an image forming apparatus, which includes a storage means for storing a recording medium on which an image is to be recorded, and an endless conveyance means for suctioning and conveying the recording medium from the storage means to a predetermined position. In this case, the endless conveying means is driven at a constant speed, and the moving speed is variable only in the vicinity of the accommodating means, and the cleaning means for cleaning the endless conveying means is driven at a constant speed of the endless conveying means. The problem has been solved by a paper feeding device of an image forming apparatus, which is characterized in that it is provided in a moving part.

[Effect]

According to the invention, the endless conveying means carries out a conveying movement at a constant speed, with only a part of the endless conveying means being additionally moved horizontally or vertically or simultaneously in the horizontal and vertical directions; By selecting the speed, the endless transport means locally slows down or stops relative to the stationary member, for example the recording medium, or moves in the opposite direction.

When the recording medium is brought into contact with the recording medium at a relative speed of zero, it becomes possible to feed the recording medium in its contained state. At this time, there is no relative misalignment between the endless conveyance means and the recording medium.

An alternating electric field pattern is formed on the conveyance means by the charging device, and the conveyance means moves to a feeding position from the storage means.

The charging device is arranged upstream of the storage means in the moving direction of the conveyance means. The charging device is configured to apply a high voltage of a constant frequency to form an alternating electric field pattern of a constant shape when charging at a position where the conveying means moves at a constant conveying speed. When the conveyance means is charged at a position where the relative movement speed changes, the frequency of the applied voltage of the charging device is changed in accordance with the change in the relative movement speed, and the charging device is configured to form an alternating electric field pattern with a constant shape. Ru.

Even if the relative movement speed changes, the density of the charged charge pattern formed on the conveying means is constant regardless of the change, that is, a constant alternating electric field pattern is formed. By forming a constant alternating electric field pattern, the attraction force to the recording medium is uniformly formed, and stable conveyance performance is obtained.

The endless conveyance means uses a cleaning means to clean the surface that comes into contact with the recording medium. At that time, the cleaning means
By arranging the constant speed moving portion to abut the endless conveyance means, the abutting portion of the cleaning means always abuts against the conveyance means under constant movement conditions. Therefore, the speed of the conveying means is changed in the portion where the recording medium is fed from the storage means, and even if the variable speed conveying means is subjected to a speed change action, the cleaning means is not affected by the speed change. Therefore, poor cleaning and uneven wear will not occur.

〔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.

In FIG. 2, the copying main body 3 includes an image forming section 5 and a paper feed bag W.
6.

As shown in FIGS. 1 and 3, the scanner device 2 placed on the copying body 3 may be configured as an integral structure, as opposed to being formed as a separate structure separated 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 that illuminates and scans the document on the contact glass 11, a first mirror 14 that scans together with the lamp 13 and reflects light reflected from the document, and a first mirror 14 that scans the document on the contact glass 11. It has a second mirror 15 and a third mirror 16 that sequentially reflect the 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 W7. 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 a cylinder lens 24 that 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. After a certain period of time after the synchronization signal is output from the synchronization detection sensor 30, the scanner device W
One line of image data is output based on the read image information from No. 2. 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 an angry light layer coated on its surface. Organic photoconductor (OPC) as a photoconductor sensitive to the wavelength of semiconductor laser 780 nm, a-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.

During charging 32, the surface of the photoreceptor 31 is uniformly (-) charged using a scorotron system having a grinode on the photoreceptor side.
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 belt 53 of the paper feeder 6. A (+) charge is applied by the transfer charger 34 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 235. 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.Measurement of the 0 reflection density is performed by writing a certain pattern (for example, a pure black or halftone dot pattern) using the writing optical device 7 at a position corresponding to the reading position of the photosensor. The density of the image is determined from the ratio of the reflectance of the pattern area after development to the reflectance of the photoreceptor other than the pattern area, and if it is too light, a toner replenishment signal is issued.Also, it takes advantage of the fact that the density does not increase even after replenishment. It is also possible to detect an insufficient amount of toner.

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 rows. 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 f6 has a conveyance device 51 and a storage means, such as a paper feed tray or a paper feed cassette.

Transport device t! 51 has an endless conveying means, for example, an endless circulating running 11 conveying belt 53;
is wound around the drive roller 54, first driven roller 55, second driven roller 56, and adjustment roller 57 in this order. The conveyor belt 53 is conveyed 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 charger 34 facing the photoreceptor 31 is arranged facing the inner surface of the conveyor belt 53.

Between the first driven roller 55 and the second driven roller 56,
An appropriate number of pickup rollers 58, for example, two pickup rollers 58, are arranged at appropriate intervals inside the conveyor belt 53, and each pick-up roller 58 is formed to be vertically movable. The interval between the pink-up 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 bearings 60 are 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 pulley 65 and driven pulley 67, and the drive heald 69 is attached to the slider 60.
is fixed 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 60
By moving along the guide shaft 62, the first driven roller 55 is moved substantially horizontally.

The home sensor 71 detects when the first driven roller 55 is at the home position, which is the right end position in the figure.

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 Vm/s of the first driven roller 55 is determined by the conveyor belt 5
3 conveyance speed, that is, 1/ of the circumferential speed v wa / s
2, that is, V = v / 2, when the first driven roller 55 moves to the left side of the rotation, the conveyor belt 53 traveling in the direction of the arrow passes from the adjustment roller 57 to the second driven roller 56 to the first driven roller 55. In the section leading to , that is, the speed fluctuation region, the circumferential velocity V / S and the moving speed ■ Peng /
Due to the action of S, the upper conveyor belt 53 is apparently speed-changed to a stopped state and can be maintained 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 roller 5 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 belt 53, and transfer, separation, and fixing are performed in some way. This can be done without any side effects. In the constant speed fII region where the conveyor belt 53 always runs at a constant speed, for example, the drive roller 5
If cleaning is performed using the belt cleaner 72 provided below the belt 4, cleaning defects will not occur.

When the conveyance belt 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 740 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 belt cleaner 72, a charging roller 76 disposed near the belt cleaner 72 forms a certain charge pattern on the conveyor belt 53. When a charge pattern is formed in the speed fluctuation region 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 is applied in accordance with the change in the feeding speed of the conveyor heald 53. By performing control such as changing the frequency of the charge, the conveyor belt 5
A certain charge pattern can be formed on 3.

The paper feed tray 52 is a front-loading recording paper stacking device, and the paper feed tray 52 is pulled out from the front of the copying machine 1, recording paper 77 is set 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 setting an A3 size paper, the central fence 78 is opened between the L tray chambers 802810 as shown in FIG. 8, and the recording paper is placed inside the L tray chamber 802810 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 80 and 81 formed on the left and right sides of the central fence 78.
2 is provided.

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

As shown in FIGS. 7 to 9, the central fence 7 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 vertically 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 84.
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 locked by the fingers 89 locking into the protruding locking portions 90 formed on the frame portion 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. nail 89
When the person a pushes the upper face guide 83 sideways with enough force to cause the hook 91 to come off due to elastic deformation, the center fence 78 rotates clockwise in the figure and falls over, causing it to fall into the right tray chamber 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 placed on the paper feed tray 52 so as not to interfere with the recording paper placed on the rising tray 82.
It is formed so as to be buried in a recess 92 formed in the frame portion 52a. The claw 89a of the fallen lower face guide 84 presses a switch 93 as a paper size sensor to detect that the center fence 78 has fallen and the right tray chamber 80 and left tray chamber 81 are in communication. .

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 pink up rollers 5B that presses against the middle fence 7B is placed directly above the upper face guide 83 of the middle fence 7B, and the other one is placed directly above the upper face guide 83 of the right fence 79. be done.

As shown in FIG. 10, one pick-up roller 58 disposed directly above each face guide 83 and one or more other pickup rollers 58 are rotatably supported by, for example, a support plate 95 as a set. In the example shown in FIG. 0, two pickup rollers 58 are supported as one set by the carrier plate 95. Each set of pickup rollers 58 is supported at the same height.

The carrier plate 95 is always pulled up to a fixed position by a tension spring 96, and the conveyor belt 53 is pulled up by the upper face guide 83.
It is located away from the top surface of. The support plate 95 abuts 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 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 a radius R1 from the center of the axis 98, for example, a radius of 10 m, and the remaining 216° range is divided into 108°, and the distribution is divided from the center point A with a radius R2, for example 6III11 from the center of the axis 98. The arc surface B and the center point A are connected by 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 9B. The stopper 104 is the first
As shown in Figure 4, there are two stepped portions 105.10 on the outer periphery.
6, and the claw portion of the locking bar 107 engages with one stepped portion 105.
The rotation of the pad 104 is prevented. 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. A locking bar 107 is attached to the first stepped portion 105.
In the locked state, point A of the paper feed cam 99 is in contact with the support plate 95 as shown in FIG. 10, 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 12 Orpm, is caused by the spring clutch 1.
00 to the collar 104, and when paper is fed, the paper feed solenoid 110 is energized and the stopper 104 is released, and the stopper 104, which has always been subject to rotational moment, is
started rotating because the grand stop was released, and it continued for 0.25 seconds.
Afterwards, the paper feed solenoid 110 is deenergized and the locking bar 107
contacts 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 portion 106 has passed, and after one rotation, the claw of the locking bar 107 is stopped by the first step 105 of the stopper 104, and the stopper 104 is stopped. This operation causes the cam 99 to rotate once every 0.5 seconds. The pickup roller 58 moves down 4 m in 0.15 sec together with the carrier plate 95, and stops for 0.2 sec. At this time, as shown in FIG. 11, the arcuate surface B of the cam 99 contacts the support plate 95 and pushes the support plate 95 down. After stopping for 0.2 seconds, it returns to the original position in 0.15 seconds. The pickup roller 58 and a means for pushing down the big unroller 58, such as a pushing device 97 and a support plate 95, are connected to the transport heald 53.
Acts as a suction operating means for activating suction.

The gap between the conveyor belt 53 and the recording paper 77 in the non-feeding state is approximately 4 mm, and the gap with the upper face guide 83 is 2 mm.
It is. Therefore, when the pickup roller 58 moves downward, it moves downward by 2 m and comes into contact with the upper face guide 83.
While further pushing down the upper face guide 83, press 2mTl1.
! do. At this landing position, the conveyor belt 53 is placed on the recording paper 77.
touches.

At this time, the recording paper 77 is attracted 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 58 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, and then stops. . As a result, recording paper 7 due to paper feeding
It is possible to correct the change in the lowering of the upper surface position of 7, 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 by the attraction force generated by an unequal electric field rather than by 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 it is easy to remove static electricity after transfer. 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 FIGS. 15 and 16, the lifting device 123 that moves each lifting tray 82 up and down moves the lifting tray 82 up and down at four locations.
The wires 111 are fixed to the wires 111, respectively. The first wire 1lla among the four wires 111 is connected to the first guide pulley 1
12, the end is turned by the second guide boob I7113 and 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 11 is fixed to the rising tray 82 on the opposite side from the first wire 1lla and the second wire 111b.
1C and the fourth wire 111d are each wound around a second drive pulley 116 whose ends are fixed to the shaft 115. Similarly to the first wire 111a, the third wire 111c is guided by the third guide pulley 117 and the fourth guide pulley 118, and is wound around the second drive pulley 116.
Similarly to the second wire 111b, the wire 11d is guided only by the fourth guide pulley 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 receives force.

It is connected to a tray motor 122 via a ring 121. The camp ring 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 elevating tray 82 and the elevating 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 rises due to the rotation of the tray motor 122, but when the top surface of the recording paper 77 comes into contact with the conveyance heald 53 and receives pressure, the electromagnetic clutch 119 is activated to slip. As a result, 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 1. At this time, the drive half 121a of the cambling attached to the side of the copying machine 1 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 and 1 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,
Since the stopper 104 has not yet completed 115 rotations (72''), 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 120" T degrees, the locking bar 1
The claw portion 07 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 conveyor belt 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 recorder 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 0.1 sec, 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. Stopper 1
04 rotates by exactly 240'', the locking bar 107 again hits the first stepped portion 105 of the stopper 104 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 A3 size recording paper is set in the paper feed tray 52 across the first tray 52' and the second tray 52# by folding down the central fence 7, the above-mentioned raising tray operation and cam operation are performed on the first 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 bag 23B, the claw 41 is attached to the paper discharge path 42.
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 includes a reversing path 45 as a branch path, and at the branching position, it connects directly to the paper feed tray 52 and the reversing path 45.
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 roller 45 is nipped by the reversing roller 48 and sent.
When the reversal sensor 125 detects the trailing edge of the recording paper, the reversing roller 48 reverses the recording paper and the recording paper is reversely fed. The reversely fed recording paper is guided by the second switching claw 46b toward the feed roller 49 of the return guide path 44 and is discharged onto the paper feed tray 52.

Like A3 copy, the first tray 52' and the second tray 5
When using 2# at the same time, the tray motor 122 is reversely rotated to lower the ascending tray 82 by a certain amount after the paper feeding operation for front copy (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 the front side copy is 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 the reversal of (lowering I(
Memorize movement I)), recording paper 7 with a copy on the front side
7 is inserted into the second tray 52#, the ascending tray 82 is returned to its original position, and the feeding operation for backside copying is performed. After the backside 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 raising tray 82 of the second tray 52# is lowered by a certain amount by reversing the tray motor 122 (using an encoder not shown). After the recording paper 77 on which the front side has been copied is inserted into the second tray 52'+=, the ascending tray 82 is returned to its original position and the feeding operation for the back side copy is started. After copying the back side, the recording paper 77 is discharged from the paper discharge path.

A recording paper upper limit sensor 126 is provided above the second tray 52', and when in double-sided image forming mode, even if you try to lower the ascending tray 82, when it is full of recording paper, it will not be possible to perform double-sided copying on the operation panel. 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 purpose, a manual paper feeder 130 is provided.

The manual paper feed device includes a manual paper feed door (not shown) provided in the machine frame of the copying body 3, a guide plate 1-31, 132 that guides the recording paper inserted through the core paper 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 feeder W130, a manual 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, it is possible to use a paper bank device 4 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. 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 136 that is open at the bottom and guides the recording paper fed from the paper bank device 4.
will be provided. The paper feed path 136 is formed to be able to feed the recording paper to a home position, for example, a nip 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.
A three-stage tray consisting of a ) ray 201, a 2nd PB) ray 202, and a 3rd PB) ray 203, and a 4th PB) ray 204 with a maximum loading capacity of 2000 sheets are equipped. Paper is fed from each PB) ray 201 to 204 by one paper feeding conveyance device 20.
5.

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 belt 21B includes a fixed driving roller 211, a movable tension roller 212, a fixed turning roller 213, a driven roller 214, a pickup roller 215, a pair of belt speed change rollers 216, and an auxiliary turning roller. It is wrapped around the entire roller 217.

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 device 4, and the paper feed unit 220 is vertically slidably guided by the guide rods 207. Ru. Paper feed unit 2
20 has a sheet feeding unit front side plate 222 and a sheet feeding unit back side plate 223 to which a bearing 221 that is slidably attached to a guide rod 207 is fixed. Paper feed unit front plate 2
22 and the pickup roller 2 so that both ends thereof are supported by the rear side plate 223 of the paper feed unit, respectively.
15 and an auxiliary turning roller 217 are arranged.

A pickup auxiliary roller 219 is arranged to face the driven roller 214 so as to press the conveyor belt, that is, the PB endless belt 218, and the paper feeding unit front side plate 222
The paper feed unit is rotatably supported by the odor side plate 223. The pickup auxiliary roller 219 uses PB when changing the conveyance direction.
It serves to prevent the recording paper from peeling off from the surface 218.

A shaft 21 that rotatably supports the pick-up roller 215
Both ends of the paper feeding unit 5a are movably supported in an elongated hole 224 formed in the front side plate 222 of the paper feeding unit and an elongated hole 225 formed in the back side plate 223 of the paper feeding unit so as to be movable in a substantially horizontal direction. Furthermore, both ends of the shaft 215a of the pink-up 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 23 is rotatably supported by the paper feed unit front plate 222 and the paper feed unit odor 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 odor side plate 223, respectively. The pickup roller 215 is reciprocated along the elongated lengths 224 and 225 by driving the motor 230 in forward and reverse directions. Axis 21 of pink up 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 pickup roller 215 is at the home position. The upper end detection sensor 233 is the PB held 218
It is detected that the paper feeding surface of the recording paper is at a height of 5 m from the top edge of the recording paper, and the paper feeding operation is performed from this position.

The tool display 2250 that moves the paper feed unit 220 up and down is powered by a motor 2 fixed to the back side plate 206 of the paper puncture 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 belts 254 wound around the drive pulley 252 and the driven pulley 253, respectively. The timing belt 254 is fixed to the front side plate 222 of the paper feed unit and the odor side plate 223 of the paper feed unit, respectively, and when the timing belt 254 is moved by the forward/reverse drive of the motor 251,
0, that is, the paper feed half unit front side plate 222 and the paper feed unit odor side plate 223 are moved up and down.

Brackets 237 are respectively fixed to a front shaft 236a rotatably supported by the paper feed unit front side plate 222 and a rear shaft 236b rotatably supported by the paper feed unit odor side plate 223. Both ends of the pair of belt speed change rollers 216 (216a, 216b) are supported. That is, the first belt speed change roller 216a and the second belt speed change roller 216b are supported by the bracket 237,
PB that runs between both belt speed change rollers 216a and 216b due to the rotation of the shaft 236 (236a, 236b)
The relative position with respect to the bevel 218 is changed. Inner shaft 236
(The front shaft 236a and the rear shaft 236b) are rotationally driven by a motor 238 to which the rear shaft 236b is connected. Rear shaft 23
A tweeter 239 is fixed to 6b, and the tweeter 239
is the sensor 240 fixed to the rear side plate 223 of the paper feed unit.
By operating the belt speed change roller 216, the home position of the belt speed change roller 216 is detected. By rotating the shaft 236, the belt speed change roller 216 rotates the PB bevel 2 before the sheet feeding operation.
18 is wound around the first belt speed change roller 216a and the second belt speed change roller 216b, and the shaft 236 is rotated in the opposite direction during paper feeding operation to return the wound PB web 218. The PB bevel is returned to its original position, and the feeding speed of the PB heald 218 is controlled.

The transport of the PB bevel 218 is driven by a transmission device that includes 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. This is done by rotationally driving 211.

In order to attract and convey the recording paper, a charging roller is provided on the PB web 21B to form a charge density pattern. In the example shown in FIG. 0, an auxiliary turning roller 217 is used as a charging roller, but it may be provided separately. An alternating current voltage, for example, ±2 KVP-P, 26 Hz, is applied to the charging roller 217 from the high-voltage power source 245 at a position before it contacts the recording paper, and charge densities of −σ and +σ are alternately applied to the surface of the PB web 218 from the collector. For example, a striped charge density pattern arranged at a period of five cabinets 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 bevel 21B.

The first PB tray 20 is inside the machine frame of the paper puncture device W4.
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 trays 201 to 3rd PB tray 2o3 have a side fence 265 for determining the position of recording paper 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 Ray 201 for easy loading and unloading.
67 may also be provided.

In FIG. 21, for example, the fourth PB tray 204 as a large tray with a maximum loading capacity of 2,000 sheets is the same as the first PB tray in FIG.
Similar to the tray 201, a side fence 268, an end fence 269, and a handle 267 may be provided.

4th PB) Since the paper capacity is large in Ray 2°4, it is preferable to form the side fence 268 in an L-shape to guide the paper in the front, back, left, and right directions to prevent the paper from shifting. The cross-shaped side fence 268 is shaped so as not to interfere with paper feeding.

The PB bevel 53 in the copying body 3 is formed with a charge density pattern by the charging roller 76 and attracts and conveys the recording paper.
In the paper bank device 4, a charge density pattern is formed on the PB bevel 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 bevel 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 a driving roller 54
Move in the direction of the arrow at a constant speed U/S,
The position of the pickup roller that contacts and attracts the recording paper is located downstream of the position of contact with the charging roller 76 in the moving direction of the conveyor belt 53. Therefore, the conveyor belt 53
Before the recording paper comes into contact with the surface, an alternating current voltage is applied from the high voltage power supply 131 via the charging roller 76. As a result, a stripe-like charge density pattern is formed on the surface of the conveyor belt 53, in which charge densities -σ and +σ are alternately arranged in a U/A cycle. *Charges of opposite polarity are induced in the semiconductor layer on the back surface of the transport belt 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 dynamic force. The recording paper 77 is electrostatically attracted to the conveyor belt 53 by the force Fx in the direction perpendicular to the surface of the recording paper 77, that is, the surface of the sheet, and is held without shifting.
The paper is fed and conveyed.

When the direction perpendicular to the sheet surface is X, the transport direction is y, and the direction within the sheet surface perpendicular to the transport direction is z, the component force in each of the x, y, and z directions of the force acting on a unit volume of the dielectric is Fz ,F9,F
Letting z be as follows.

Maxwell stress tensor EyDx--, C50)) ExT)1
From 5pzEY to -4 (t-p)
EY2 Force acting on unit volume 'tx = >x 'i Side = 4 (t, p > S +
ay (Ex PY ) 士-; (E,'K)x)'ty
:6 (EYDII)↑wlErDr−=(E・D>
＋云 (Erh') This adsorption principle differs from the commonly known force of attraction between charges of opposite signs, and the above-mentioned method can be used to attract the recording paper without applying any number of charges to the recording paper. can. For this reason, even if it is used in a paper feed conveyance device of an electrostatic recording device, it will not have the same effect on the transfer process.

Although the example of the charge density pattern has a stripe shape, a checkerboard pattern may be used, and any appropriate pattern can be used.

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

In Fig. 25, the amplitude of the AC voltage is constant, for example, 4KVP.
-F, and measured the adsorption force by changing the applied frequency.From this, it can be seen that in the present invention, the period of the stripe shape is 2.
Sufficient adsorption force was obtained when the length was 0.0 m or less, especially 105 m 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 conveying belt 53 is a two-layer type, with the surface layer being a dielectric film (polyester resin 20 μm, volume resistance 1016 Ωcm) and the lower layer being a semiconductor layer (polyester Carbon dispersed in resin 80μm, volume resistance 10”0c
m) is configured as an endless belt, and is rotatably supported by a drive roller and a plurality of support rollers.

The charging roller 76 is supplied with ±2KV, 2
A 4H2 alternating voltage is applied. Further, the conveyor belt 53 is moved at a constant speed of 120 m in the direction of the arrow by a drive roller.
/s, and the paper feeding position of the recording paper is downstream from the contact position of the electrode of the charging roller 76 with respect to the moving direction of the transport heald 53. Therefore, before the recording paper is fed onto the surface of the conveyor belt 53, a charge density pattern is formed on the surface of the conveyor belt at five cycle intervals. here,
The reason why the volume resistance of the back surface of the conveyor belt 53 is set to lO@Ω1 is because if the transfer means is installed on the back surface, the volume resistance is 10'Ω.
This is because it had to be 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, the volume resistance of the back side is actually 107ΩC1~10″
If it is within the range of Ω1, 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 of a two-layer type, with the surface layer being a dielectric film (PE750 μm) and the lower layer being an endless belt made of vapor-deposited aluminum. It is rotatably supported by multiple support rows.

The volume resistance of this dielectric was set to 1016Ω1. An alternating voltage of ±2 KV and 26 Hz is applied to the charging roller 217 from a high voltage power source B. Furthermore, the PB bevel 218 is moved by a drive roller in the direction of the arrow at a constant speed of 130 cm/s, and the paper 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 bevel. be. Therefore, before the recording paper is fed onto the surface of the PB held, a charge density pattern is formed on the surface of the PB held at a period of 5 cm.

The PB bet 218 in the paper bank device 4 is the first
PB) The recording paper is sucked and fed from the tray 201 to the fourth PB tray 204. For this purpose, the display device 250 is activated, and the paper feeding unit 220
Move up and down in front of the PB tray 203 to load the 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 fourth PB tray 204
Before the recording paper is fed onto the surface of the recording paper, a charge density pattern is formed on the surface of the PB surface at five cycle intervals.

The PB bet 218 in the paper bank device 4 is the first
The recording paper is sucked and fed from the FBI-ray 201 to the fourth PB tray 204. For this purpose, the display device 250 is activated, and the paper feed unit 220 moves up and down in front of the 1st PB) ray 201 to the 3rd PB) ray 203, and reaches the paper feeding home position of the 1st PB) ray 201 to the 3rd PB tray 203. will be stopped. In FIG. 17, the fourth PB tray 20
4 is arranged offset from the first PB tray 201 to the third PB tray 203, and the paper feed unit 220 directly feeds the fourth PB tray 201 to the third PB tray 203.
It can be moved above the recording paper in the B tray, but it can also be arranged in the same line as the first FBI-ray 201 to the third PB tray 203 and moved up and down in front of the fourth PB-ray 204. .

The paper feed home position for all PB trays is a certain distance above the top edge of the recording paper, for example, a position above the top edge of the recording paper, and when the paper feed unit 220 moves to the paper feed home position of the selected PB tray, the PB bevel l-21
8 is located above the upper end of the recording paper.

When the PB web 218 contacts the recording paper and feeds the recording paper by suction, the relative speed of a portion of the PB web, that is, the contact portion with the recording paper, is changed to almost zero.

In order to change the feeding speed of a portion of the PB web 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
16 b) 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 mm,
The belt 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 21B around the belt speed change rollers 216a and 216b. In FIG. 27, the belt speed change rollers 216a and 216b are rotated by an angle .theta. from the release position where the belt speed change rollers 216a and 216b are simply contacted by the solid lines.

When the PB bevel 21B itself is not being conveyed, the amount of movement l of the PB bevel is 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-ωt, the displacement velocity V is expressed as a time derivative,
V=2rω+12ωsinωt. Here, ω is the rotational angular velocity.

When the PB bevel 21B is moving at a constant speed of 30 wm/sec and the paper feed unit 220 is descending at 150 m/see, the contact area of the PB bevel 218 with the recording paper moves at 280 m/see. Therefore, in order to stop the PB bevel 218 in the contact area with the recording paper, it is necessary to cancel this speed. For this purpose, if the displacement speed V is set to 280 /sec, the angular velocity ω,
In other words, the driving speed of the motor 238 that rotates the shaft 236 is obtained.

In other words, in the case of the 1st PB) ray 201 to the 3rd PB) ray 203, the paper feeding unit 220 moves from the paper feeding home position shown in FIG. 28A to the position where it contacts the recording paper shown in FIG. 28B. sec, and at that time, the belt speed change roller 216 transfers the PB bevel 218 to the belt speed change rollers 216a and 216b as shown in FIG. 28A.
The belt speed change rollers 216a and 216b are moved in the direction in which the belt is unwound from the wound state, for example, clockwise in the figure.
is rotated. The part of the PB web 218 that comes into contact with the recording paper is almost stationary, and the recording paper is moved to the PB web 21.
It is electrostatically attracted by the charge density pattern of 8.

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 sucked and fed. In the case of the 4th PB) Ray 204, the leading edge of the recording paper 77 is sucked away from the contact area of the PB bevel 218, so if the recording paper is conveyed as it is, the recording paper will gradually separate from the PB bevel starting from the leading edge. This will result in

Therefore, the PB web 218 descends from the paper feeding home position shown in FIG. 29(A) to the position shown in FIG. 29(B), contacts the recording paper 77 in a stationary state, and after suction,
As shown in FIG. 9C, while the paper feeding unit 220 rises and returns to the paper feeding home position, the leading edge of the recording paper is retreated by a certain amount to a position where it contacts the driven roller 214.

For example, if the paper feed unit 220 is moved backward by 20 steps, the time it takes for the paper feed unit 220 to return to the paper feed home position is 5 (m) / 150 (II+/see) = 0
．． 033 (see), and the linear velocity of the PB heald 218 in the opposite direction is 20 (m) 10.033 (see) = 6
00 (wn/5ec). Since the PB web 218 is conveyed at a constant speed of 130 m/sec, when the paper feed unit 220 moves up at 150 m/sec,
At the contact surface of the PB web 218 with the recording paper, the winding of the belt speed change roller 216 is released and rotated so that it is returned at 600+1l30-150=580/sec. Therefore, the above transition speed ■ is set to 580 m/sec.
The speed of the motor 238 is controlled by setting .

PB bebeto 2nd step 8 in the paper feeding process for the next recording paper
In preparation for the deceleration of the recording paper contact sIM, the belt speed change roller 216 is rotated in the range between 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 216' and one variable speed roller 216'' disposed between them can be used. FIG. 203, and FIG. 31 shows an example used for the 4th PB) ray 204 as shown in FIG. 29. In FIG. Then, while landing from that position to a position touching the recording paper, move to the left of the diagram and press P.
The speed of the recording paper contact area of the B bevel is reduced or stopped, and the displacement roller 216# is displaced to the leftmost position in the figure at the position where the recording paper contact area on the B side is returned to the paper feeding home position again.

In FIG. 31, a process of retracting the recording paper contact area of the PB bevel 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 descend 5 meters at m/sec and contact the recording paper is 5(■)/150(■/5ec) = 0.033
sec, and during this period, PB Bebeto 218 was 130 kaku/
In order to cancel the uniform speed drive of 150 cm/sec and the displacement of the inferior kidney due to the descending speed of the paper feed unit 220 of 150 cm/see,
The displacement roller 216# is displaced in the negative direction at 0.times./sec. This displacement is performed for 0.033 seconds, so the amount of displacement is 280 (m/5ec) X O,033 (see)
= 9.3 (m), for which displacement roller 2
16# is 280 (wm /5ec) / 2 = 1
It is sufficient to drive the motor at a constant speed of 9.3 (Peng)/2-4.7 (■) to the left in the figure at a speed of 40 (wm/5ec).

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 216' is driven at a constant speed to the left in the figure at a speed of 290 cm/sec and a displacement amount of 9.7 mm. do.

The speed change operation is performed until the axial center of the displacement roller 216# reaches the point where 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 cm is performed by constant velocity control.

〔effect〕

According to the present invention, the cleaning means always comes into contact with the conveying means subjected to a speed change action under constant movement conditions,
Cleanability was stable and uneven wear was prevented.

According to the present invention, skew feeding during feeding and conveyance of a recording medium can be prevented without providing a registration means, and
Furthermore, double feeding does not occur, and a feeding and conveying device with extremely high conveyance transferability without occurrence of jams is 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, there is no need to change the speed of the entire endless conveyance movement from feeding from the storage means to the image forming section, and therefore without reducing the copy production speed per unit time (always from the storage means at a constant and reliable speed). A feeding/conveying device capable of performing accurate 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.

[Brief explanation of the drawing]

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. 10 is a schematic front sectional view showing the storage means and the conveyance means pressing device as the suction actuation means. , FIG. 11 is a diagram corresponding to FIG. 10 showing the operating state of the conveying means pressing device, FIG. 12 is a perspective view showing the drive system of the conveying means pressing device, FIG. 13 is a front view of the cam, and FIG. 14 is an explanatory diagram of the stopper of the drive system of the conveyance 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, FIG. 17 is a schematic front view of the paper bank device, and FIG. 18 is a perspective view of the paper feeding unit. 19 is a plan view of the paper feeding unit, FIG. 20 is a perspective view of an example of the storage means, FIG. 21 is a perspective view of another example of the storage means, and FIG. 22 is a perspective view illustrating the formation of an alternating electric field on the conveyance means. Figure 23 is an explanatory front view of alternating electric field formation, Figure 24 is an explanatory diagram of a method of testing attraction force using an alternating electric field, and Figure 25 is a diagram showing the relationship between the pitch of an alternating electric field and the tensile force indicating attraction force. , FIG. 26 is a diagram showing the relationship between the applied voltage of the alternating electric field and the tensile force, and FIG. 27 is an explanatory diagram of another example of the conveying means transmission device.
Fig. 28 is an operation diagram showing the operating states of the conveying means transmission according to Fig. 27 as A, B, and C in sequence, and Fig. 29 is an example in which the relative positions of the conveying means and the storage means are different. FIG. 30 is an explanatory diagram of another example of the conveyance means transmission device, and FIG. 31 is a diagram corresponding to FIG. 30 of an example in which the speed change steps are modified from FIG. 30. 52...Accommodating means 53...Endless conveyance means 55...Followed roller 72...Cleaner (cleaning means) 76...Charging means 77...Recording paper 3 Figure 4 Figure 4 8 Figure 25 Figure 67 [mml Figure 26 1pf JOt way [Vp-p

Claims (1)

[Claims] (1) A storage means for storing a recording medium on which an image is recorded;
In a paper feeding device of an image forming apparatus, the paper feeding device includes an endless conveyance means for adsorbing and conveying the recording medium from the storage means to a predetermined position, the endless conveyance means being driven at a constant speed, and only in the vicinity of the storage means. Formed with variable movement speed,
A paper feeding device for an image forming apparatus, characterized in that a cleaning means for cleaning the endless conveying means is provided at a portion of the endless conveying means that moves at a constant speed.