JP2003160248A - Sheet conveying device and image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet conveying device and an image processor that can stably feed even a deformed document with a curl or a fold, causing no overlap feeding without lowering the productivity of a feeding device. <P>SOLUTION: In the representative constitution of the sheet conveying device and image processor, the sheet conveying device for suction-conveying a sheet has a first attracting face arranged in a position corresponding to the end face of the sheet, and a second attracting face arranged in a position corresponding to the center face of the sheet. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device for conveying a sheet in a copying machine, a laser beam printer, a facsimile, etc., and an image of a sheet original fed from the sheet conveying device is read or fed. The present invention relates to an image processing device that records an image on a sheet.

[0002]

2. Description of the Related Art Conventionally, as a technique for separating and feeding a sheet from a stack, a friction separation method utilizing a friction force between a rubber roller or a rubber belt and a sheet has been known. But,
It is known that this method has no durability because the rubber is largely deteriorated. In addition, an air feeding system that uses air suction to separate the air is also known, and it is durable because it is not a separation system that uses friction. It is known to be great.

As a technique for correcting these drawbacks, a sheet feeding device utilizing electrostatic attraction is disclosed in, for example, Japanese Patent Laid-Open No. 9-6703.
Many proposals have been made as shown in 3rd grade. In this electrostatic attraction type feeder, an unequal electric field is formed on the dielectric belt, and an alternating charge having a predetermined pitch is formed on the dielectric belt. Then, the electric potential of the sheet is raised by bringing the sheet into contact with the dielectric belt, so that an electric charge having an opposite polarity to that of the dielectric belt is formed on the sheet. The electric charges formed on the dielectric belt and the electric charges formed on the sheet are attracted by the Coulomb force, and the sheets are adsorbed on the dielectric belt and separated and conveyed one by one.

[0004]

However, in the air feeding method of the above-mentioned conventional configurations, when a deformed original such as curl or fold is to be adsorbed, the suction static pressure of the air suction is set to be considerably large. I had to do it. as a result,
In particular, when feeding thin paper, sheets other than the sheet to be adsorbed (the second and subsequent sheets) are also adsorbed, and two sheets are adsorbed (double feed). If the suction static pressure is set to a small value in order to prevent double feeding, then a heavy cardboard cannot be adsorbed and a suction failure occurs. That is, there was no suction static pressure latitude that could feed all paper types.

As a countermeasure against this, a method is generally known in which air is introduced between the suction sheet and the second and subsequent sheets to float the sheet and suck the sheet. However, with this measure, a sheet that has not been deformed can be fed, but in the deformed sheet, the deformed portion obstructs the inflow of this air, so that the sheet cannot be sufficiently floated and a separation failure occurs.

Further, in the electrostatic adsorption type feeding device of the above-mentioned conventional construction, in order to adsorb the deformed sheet, the amount of electric charge of the dielectric belt has to be considerably increased and the adsorption force must be increased. . Then, not only the sheet to be attracted, but also the second and subsequent sheets are attracted to the dielectric belt. It is considered that this is because the second and subsequent sheets are pulled by the dielectric belt because the paper charges after the second sheet also increase.

In order to solve this problem, it is considered that the suction force of the second and subsequent sheets is attenuated by keeping the dielectric belt in contact with the sheets for a predetermined time. In FIG. 18, the suction force acting on the dielectric belt and the suction sheet is shown by a solid line, and the suction force acting on the dielectric belt and the second sheet is shown by a broken line. The horizontal axis is the time from the time of contact (hereinafter, the adsorption time), and the vertical axis is the electrostatic attraction force applied to each sheet. As can be seen from the graph, it can be seen that the electric charge formed on this second sheet decays in about 0.2 seconds after the contact, and the adsorption force becomes almost zero. However, depending on the type of the sheet, for example, a transfer paper on which an image is formed with color toner has a large volume resistivity, so that the electric charge placed on the sheet is not easily attenuated even after a long time, and the adsorption force is not attenuated. . For this reason, the sheets are not separated well during feeding, and so-called double feeding occurs. Further, if the adsorption time is set too long in order to attenuate the electric charge of the second sheet, the number of sheets that can be fed in a unit time is significantly reduced, and as a result, the productivity of the image forming apparatus is also reduced.

In view of this, the present invention does not reduce the productivity of the sheet feeding device, and can stably feed even a deformed document such as a curl or a fold without causing double feeding, and a sheet conveying device and an image. It is intended to provide a processing device.

[0009]

In order to solve the above-mentioned problems, a typical structure of a sheet conveying apparatus and an image processing apparatus according to the present invention is a sheet conveying apparatus for adsorbing and conveying a sheet, and an end surface of the sheet. And a second suction surface disposed at a position corresponding to the central surface of the sheet.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of a sheet conveying apparatus and an image processing apparatus according to the present invention will be described. FIG. 1 is a bottom view of a belt unit of a sheet conveying device according to the present embodiment, FIGS. 2 to 8 are views for explaining a separating operation of the sheet conveying device, and FIG. 9 is an electric block diagram showing wiring paths of electric parts. 10, FIG. 10 is a sequence chart for explaining the operation of the electric component, FIG. 11 is a view for explaining the separation state of the sheet from the dielectric belt, FIG. 12 is a charging pattern diagram of the charging roller for charging the dielectric belt, and FIG. FIG. 14 is a diagram for explaining the knowledge of material mechanics showing the repulsive force of a deformed document such as curl or fold, FIG. 14 is a diagram for explaining the document deformation such as curl or fold, and the suction force capable of absorbing it, FIG. 15 is It is a figure which shows the example of the image processing apparatus to which the sheet conveyance apparatus which concerns on this embodiment is applied.

(Structure of Sheet Conveying Device) First, the structure of the suction belt unit 1 constituting the sheet conveying device will be described with reference to FIG. A drive roller 4 and a driven roller 5 made of metal such as SUS and grounded to GND are rotatably supported by the side plates 2 and 3 shown in FIG. The drive roller 4 can be driven by a belt drive motor 6 (see FIG. 9). A dielectric belt 7, which is a seamless belt made of PI (polyimide) having a thickness of about 75 μm and a volume resistivity of 1.0 × 10 16 Ωcm, is stretched between the drive roller 4 and the driven roller 5. The dielectric belt 7 has a thickness of about 300 μm and a volume resistivity of 1.0 × 10 ^ 16 Ωcm.
Elastomers may be used. As shown in FIG. 1, the follower roller 5 is compressed by the compression coil spring 8 to urge the dielectric belt 7.
By pushing the bush 9 in the direction of arrow A with, for example, about 1 kg. The bush 9 is configured to be movable in the biasing direction of the compression coil spring 8. The drive to the dielectric belt 7 is transmitted to the drive gear 10 fixed to the drive roller 4 from the belt drive motor 6 (see FIG. 9).

As shown in FIG. 2, the dielectric belt 7 is charged by placing a charging roller 11 on the outer peripheral surface and a metal roller 12 on the inner peripheral surface with the dielectric belt 7 sandwiched therebetween.
(See FIG. 9) is performed by applying an AC voltage. The high voltage waveform is an AC wave as shown in Fig. 12, for example Vpp = 8k.
v Outputs equivalent to 3 mm pitch per cycle. Charging roller 11
Has a conductive rubber with a surface of 1.0 × 10 ^ 15 Ωcm.

An air suction portion 14 as shown in FIG. 2 is provided in the suction belt unit 1 on the end surface of the dielectric belt 7 on the downstream side in the conveying direction. Here, the end surface of the sheet is within a region of 30 mm or less from the edge that is the sheet boundary toward the center of the sheet. On the other hand, the dielectric belt 7 is arranged in a region other than the end face of the sheet, that is, the center face of the sheet. The air suction unit 14 is a belt roller 15a, 15 which is a metal shaft.
A seamless suction belt 16 formed of, for example, EPDM (ethylene propylene diene rubber) or the like and having a suction hole 16a of about φ2 on its surface is stretched with a predetermined tension.

The suction belt 16 is driven by a belt roller 15b.
Further, the drive transmission is performed from the driven roller 5 by the timing belt 17. That is, the drive of the suction belt 16 and the drive of the dielectric belt 7 are synchronized. The peripheral speed of the suction belt 16 (sheet conveying speed V1) is set to be about 5% slower than the peripheral speed of the dielectric belt 7 (sheet conveying speed V2). The belt rollers 15a and 15b are belt side plates 18,
It is rotatably supported by 19. Belt side plates 18 and 19 are PO
Eccentric cam 20 made of resin such as M (polyacetal)
The eccentric cam shaft 20 to which a is fixed is movable in the vertical direction in FIG. The eccentric cam shaft 20 is rotatably supported by the side plates 2 and 3, and a drive is transmitted to a gear 21 by a duct lifting motor 22 (see FIG. 9) which is a pulse motor to rotate a predetermined angle.

Inside the suction belt 16, belt side plates 18 and 19 are provided.
A duct 23 is provided which is supported and fixed to and has an opening downward as shown in FIG. The duct 23 extends to the outside of the side plate 2 through an escape hole 2a formed in the side plate 2 shown in FIG. 1, and the suction portion of a suction fan 24 is connected to another opening (not shown). The suction fan 24 is preferably a centrifugal blower such as a sirocco fan capable of obtaining a large static pressure. Sheet suction surface 16b of suction belt 16 which is the first suction surface
Is the sheet suction surface 7 of the dielectric belt 7, which is the second suction surface.
It is designed so that it can move about ± 10 mm in the vertical direction around a. Further, the longitudinal relationship of the sheet suction surface 16b of the suction belt 16 is set to have the same width as the sheet suction surface 7a of the dielectric belt 7 as shown in FIG. In the present embodiment, the width is the same, but the width of the sheet suction surface 16b may be reduced so that suction is performed at the central longitudinal portion of the dielectric belt 7.

(Suction and Separation Operation of Sheet Conveying Device) Next, the operation of adsorbing, separating, and conveying the sheet P will be described step by step with reference to FIGS. 2 to 8 and the sequence charts a to q of FIG. To do. In Fig. 2, first, AC power supply
The bias voltage described above is output from 13 (a), and an alternating charge of about 3 mm pitch is formed on the dielectric belt 7.
At the same time, by driving the belt drive motor 6, the dielectric belt 7 is driven in the conveying direction (the arrow direction in FIG. 2) (b), and the suction fan 24 starts rotating (c). Then, the dielectric belt 7 is rotated for a predetermined time, and when sufficient charge is formed on the dielectric belt 7, the belt drive motor 6 and the AC power supply 13 are turned off (p, q). The duct lifting motor 22 (see FIG. 9) is controlled in advance so that the position of the sheet suction surface 16b is about 10 mm from the sheet suction surface 7a of the dielectric belt 7 in the anti-suction direction.

Next, as shown in FIG. 3, the sheet stack stacked on the sheet tray 25 is lifted by driving the tray elevating motor 26 (see FIG. 9) to move the link 27 upward in the direction of the arrow in the figure. . Then, the leading end portion of the sheet P is sucked onto the sheet suction surface 16b of the suction belt 16. As a result, the static air pressure in the duct 23 rises, and the rotation speed of the suction fan 24 also increases accordingly. When the fan rotation speed sensor 30 detects this (g), the duct suction motor 22 is operated to raise the air suction portion 14 (h). The rising speed of the air suction unit 14 is set to be the same as the rising speed of the sheet tray 25.

Next, as shown in FIG. 4, the dielectric belt 7 contacts the upper surface of the sheet bundle. A sheet surface detection sensor 28 is arranged above the sheet tray 25, and the sheet surface is detected by raising a rotating roller 29 that allows the sheet bundle to move in the vertical direction. When the upper surface of the sheet bundle is detected by the sheet surface detection sensor 28 (e), the tray lifting motor 26 is stopped (f),
The upper surface of the sheet bundle contacts the dielectric belt 7. At this time, the uppermost sheet P1 of the sheet bundle is polarized by the alternating charges formed on the dielectric belt 7, and charges having a polarity opposite to that of the dielectric belt 7 are formed on the upper side of the sheet P1. As a result, the sheet P1 is attracted to the dielectric belt 7. The sheet suction surface 16b of the air suction unit 14 is the dielectric belt 7
After the sheet is lifted up to about 10 mm from the sheet suction surface 7a in the suction direction, it is stopped by stopping the duct lifting motor 22. The amount of this rise is a detection means for detecting the type and thickness of the sheet to be fed, or the usage environment, specifically, a paper type switching monitor 31 (see FIG. 9) operated by the user, an environment sensor (not shown), etc. Information is determined by the CPU 32 comprehensively. For example, for thin paper such as 52 g / m ^ 2, the rise amount of the air suction unit 14 is increased, and for thick paper such as 209 g / m ^ 2, the rise amount is decreased. Specifically, the amount of rise is reduced under high temperature and high humidity environments such as 40 ° C and 80%, and 30 ° C and 5%
In a room temperature and low humidity environment like the above, the amount of increase is large.

After the above suction operation is completed, next, as shown in FIG. 5, the tray elevating motor 26 is reversed to lower the sheet tray 25 (i). Adsorbed sheet P1 is about 10mm
Since the suction surface 7a and the suction surface 16b having the steps are sucked, the bent portion P1a is formed. Fig. 11 shows when the sheet is adsorbed.
FIG. 6 is a diagram showing a state in which two sheets P1 and P2 are adsorbed on a dielectric belt 7. The attraction force of the sheet P1 is exerted by the Coulomb force acting between the electric charge e1 formed on the dielectric belt 7 and the electric charge e2 formed on the sheet P1 by polarization. The attraction force of the sheet P2 to the dielectric belt 7 is the charge e1.
And Coulomb force acting between charges e3. When the sheet is adsorbed,
P1 and P2 are deformed like the bent portion P1a, and the sheet P2 is separated from the sheet P1 by the restoring force. When the leading edge of the sheet P2 is peeled off, the entire area of the sheet P2 is gradually peeled off due to the weight of the peeled sheet. In a high temperature and high humidity environment, the sheet P shown by the broken line in FIG.
Since the suction force between the sheet P1 and the sheet P2 is immediately attenuated, the sheet P2 is easily separated from the sheet P1 even if the amount of rise of the air suction unit 14 is small. However, under normal temperature and low humidity environment, the suction force between the sheet P1 and the sheet P2 is not easily attenuated, so that the sheet P1 and the sheet P2 are not separated unless the amount of rise of the air suction portion 14 is large.

Next, as shown in FIG. 6, the AC power source 13 is turned on (k) and the belt drive motor 6 is driven (j) to convey the sheet P1. Since the peripheral speed of the suction belt 16 is about 5% slower than the peripheral speed of the dielectric belt 7, the sheet P1 is conveyed while forming the loop P1b. This loop P1b also has a separation effect when both the sheets P1 and P2 are adsorbed. FIG. 8 is a diagram showing this action. Sheet P adsorbed together on the dielectric belt 7
1 and the sheet P2 have a function of moving the sheet P2 downward by a loop P1b formed when the sheet P1 is conveyed. By this action, the sheet P2 is returned to the sheet bundle when the sheet P1 is conveyed. The amount of loop P1b is set to about 10 mm. Also, the loop amount of the loop P1b may be controlled depending on the paper type, environment and the like.

Then, as shown in FIG. 7, the sheet P1
When the sheet is nipped by the pair of conveyance rollers 33 and reaches the sheet detection sensor 34 (l), the AC power source 13, the belt drive motor 6, and the suction fan 24 are stopped (m, n, o). Then, after that, the duct lifting motor 22 is reversed and the suction surface 16 of the suction belt 16 is
b is lowered to the position shown in FIG. 2 to prepare for the next feeding. The above is the feeding operation of one feeding cycle, and this is repeated when continuously feeding.

(Suction Force of Suction Fan) Next, let us consider the suction force of the suction fan 24 capable of sucking a curled or bent deformed document. It is better to set the suction force of the suction fan 24 as large as possible, but a large suction fan 24 is required to obtain a large suction force, which is disadvantageous to noise and space. That is, it is necessary to select an appropriate fan that can absorb curls and folds. FIG. 13 (a) shows the sheet P3 which is folded up, and FIG. 13 (b) shows the sheet P4 which is folded down.
FIG. 6 is a diagram assuming a case where the sheet is attracted to a sheet suction surface 16b of 6. The height of the break is δ and the lever length is L.

The suction force for adsorbing the upper folded sheet P3 shown in FIG. 13 (a) to the sheet adsorbing surface 16b is the load when the both-end supporting beams of length 2L as shown in FIG. Equivalent to W1. That is, according to the knowledge of material mechanics, W1 = 6EIδ / L3 E: longitudinal elastic modulus of the sheet P3 I: second moment of area of the sheet P3.

The attraction force for attracting the downwardly folded sheet P4 shown in FIG. 13 (b) to the sheet attraction surface 16b is the load when the cantilever of length L as shown in FIG. 13 (d) bends by δ. Equivalent to W2. That is, W2 = 3EIδ / L3. From the above equation, since W1 = 2 × W2,
The adsorption area of W1 corresponds to twice the adsorption area of W2. Therefore, the upper and lower folds can be adsorbed with the same stress.

FIG. 14 is a graph showing the amount of folding of a sheet that is folded down and that is folded up on the horizontal axis, and the adsorption stress of the belt on the vertical axis. It is E at L = 15 mm of 80 g / m ^ 2, which is plain paper. It is a result of calculating I. Normally, the maximum bending amount is about 10 mm, so it can be seen that if the belt adsorption stress is 0.04 g / mm ^ 2, the sufficient bending amount can be absorbed. As described above, if the suction force N1 of the suction belt 16 is set to about 0.04 g / mm ^ 2, the deformed document can be sucked.
On the other hand, the suction force N2 of the dielectric belt 7 is 0.001 g / mm ^
It is set to about 2. With this suction force, the deformed original cannot be sucked, but a normal sheet can be sucked. That is, the suction force N1 of the suction belt 16 and the suction force N2 of the dielectric belt 7
Are set to satisfy the relationship of N1> N2.

(Image processing apparatus) The image processing apparatus shown in FIG.
Reference numeral 37 denotes an electrophotographic copying machine, and the image reading section at the top of the apparatus is an automatic document reading apparatus 3 to which the present invention is applied.
5, having a document reading unit 38 as an image reading unit, a feeding device 36 to which the present invention is applied to the image forming unit at the bottom of the apparatus, a photosensitive drum 42 as an image forming unit, a developing unit 43, and the like. There is.

The originals stacked in the image reading section are fed and conveyed by the automatic original reading apparatus 35, and the original reading section 38.
The image is read by, the document table belt 39 conveys the image on the document table 40, and the sheet is discharged onto the discharge tray 41. A latent image is formed on the photosensitive drum 42 according to the read image information, and the developing unit 43 forms a toner image.
The sheet P placed on the feeding device 36 is separated and fed by the suction belt unit 1, and is conveyed to the transfer separation unit 45 via the transfer path 44. The sheet P on which the toner image formed by the transfer separation unit 45 is transferred is a conveyance unit 46 and a fixing device 47.
It is discharged to the outside of the image processing device 37 via the.

In this embodiment, a combination of air suction and electrostatic suction is shown, but air suction and air suction or electrostatic suction and electrostatic suction may be combined.

[Second Embodiment] A second embodiment of the sheet conveying apparatus and the image processing apparatus according to the present invention will be described. FIG. 16 is a diagram illustrating the configuration of the sheet transporting device according to the present embodiment, FIG. 17 is a partially enlarged view illustrating the separating operation of the sheet transporting device, and the portions overlapping the description with the first embodiment will be described. The same reference numerals are given and the description is omitted.

The suction belt unit 1 of the first embodiment
In the configuration, the duct 23 is arranged in the suction belt 16 of the air suction unit 14 to suck the sheet, whereas the air suction unit 49 of the suction belt unit 48 according to the present embodiment,
The difference is that a suction drum 50 is provided. The suction drum 50 is a cylindrical roller having a plurality of circular holes 50a on its circumferential surface. The circular hole 50a is formed so as to have the same width as the dielectric belt 7. A suction fan (not shown) is connected to the suction drum 50, and the static pressure in the suction drum 50 rises when the suction fan is operated. The rotation of the suction drum 50 is connected from the dielectric belt 7.
The adsorption / separation operation is the same as that of the first embodiment, and thus the description is omitted.

FIG. 17 shows how the sheet P1 is sucked and conveyed, but the sheet suction surface 50b of the suction drum 50, which is the first suction surface, is also attracted by the sheet suction surface 7a of the dielectric belt 7. The position is set to about 10 mm. The peripheral speed of the suction drum 50 is set to be about 5% slower than the peripheral speed of the dielectric belt 7. The effect of this step difference and peripheral speed difference is as described in the first embodiment.

As a peculiar effect of this embodiment, the sheet P1 is adsorbed by the cylindrical suction drum 50 so that the sheet P1 is adsorbed along the curvature of the suction drum 50. This is because when two sheets P1 are adsorbed at the time of conveyance, in addition to the separation effect of the loop P1b, the curvature separation effect of the curvature portion P1c of the sheet P1 along the suction drum 50 is obtained. Therefore, the separability of the sheet can be further improved as compared with the first embodiment.

[0033]

As described above, in the sheet conveying apparatus and the image processing apparatus according to the present invention, the first suction surface arranged at the position corresponding to the end surface of the sheet and the position corresponding to the central surface of the sheet. By having the second suction surface arranged and being individually movable in the contacting / separating direction with respect to the sheet, a step formed by the first suction surface and the second suction surface is formed. As a result, when two sheets are adsorbed, the separating effect due to the deformation restoring force of the sheets acts and the separability can be improved. In addition, by adsorbing the sheet end face and other portions separately, the degree of freedom of adsorption and separation is increased, and the allowable range of the sheet to be conveyed can be expanded.

Further, by sucking the sheet end face and the center face respectively with the suction force, the suction force of the end portion having a deformed portion such as curl or fold is increased, and the center face is set to be smaller than the suction force. It can be transported without using extra energy, which is advantageous for noise and energy consumption. When two sheets are adsorbed, the adsorbing force should be as small as possible to separate the second and subsequent sheets. That is, the separability can be improved by setting the suction force to the required minimum except for the necessary portion.

Further, the deformed portion of the sheet can be surely adsorbed by adhering the sheet end face first in the order of adsorption. The end surface of the adsorbed sheet is easily separated, and most of the exfoliation of the sheet is separated from the end portion. Therefore, it is very effective to adsorb the end surface of the sheet first.

Further, by making a difference between the transport speed of the first suction surface and the transport speed of the second suction surface, a loop is formed when the sheet is transported. This loop has the action of lowering the second and subsequent sheets when two sheets are adsorbed, and can further improve the separation effect.

By improving the separability as described above,
It is possible to suck and feed deformed originals, various sheets and originals that cannot be separated by the conventional electrostatic feeder. For example, a color original having a high resistance of an original or a thin paper such as an original drawing for drawing can be separated, so that the usage of the image processing apparatus can be expanded.
Further, the improvement in separability shortens the time per feeding cycle. In particular, in electrostatic feeding, it was necessary to wait while keeping the dielectric in contact with the sheet in order to attenuate the sheet charges of the second and subsequent sheets, but if the present invention is applied, this is no longer necessary. As a result, the speed of feeding can be increased, and the usage can be expanded.

Even when the first suction surface is of the air suction type, it can be constructed on a small scale as compared with the conventional air feeding method of entirely sucking air, so that low noise, It can save space.

[Brief description of drawings]

FIG. 1 is a bottom view of a belt unit of a sheet conveying device according to a first embodiment.

FIG. 2 is a diagram illustrating a separating operation of the sheet conveying device.

FIG. 3 is a diagram illustrating a separating operation of the sheet conveying device.

FIG. 4 is a diagram illustrating a separating operation of the sheet conveying device.

FIG. 5 is a diagram illustrating a separating operation of the sheet conveying apparatus.

FIG. 6 is a diagram illustrating a separating operation of the sheet conveying device.

FIG. 7 is a diagram illustrating a separating operation of the sheet conveying apparatus.

FIG. 8 is a diagram illustrating a separating operation of the sheet conveying device.

FIG. 9 is an electrical block diagram showing a wiring route of an electrical component.

FIG. 10 is a sequence chart explaining the operation of the electric component.

FIG. 11 is a diagram illustrating a separated state of a sheet from a dielectric belt.

FIG. 12 is a charging pattern diagram of a charging roller that charges a dielectric belt.

FIG. 13 is a diagram for explaining the knowledge of material mechanics indicating the repulsive force of a deformed document such as curl and fold.

FIG. 14 is a diagram for explaining deformation of a document such as curl and fold and suction force capable of absorbing the deformation.

FIG. 15 is a diagram showing an example of an image processing apparatus to which the sheet conveying apparatus according to the present invention is applied.

FIG. 16 is a diagram illustrating a configuration of a sheet conveying device according to a second embodiment.

FIG. 17 is a partially enlarged view illustrating the separating operation of the sheet conveying device.

FIG. 18 is a diagram illustrating the attraction force acting on the dielectric belt and the attraction sheet.

[Explanation of symbols]

1 ... Suction belt unit 2 ... Side plate 2a ... hole 3 ... Side plate 4 ... Drive roller 5 ... driven roller 6 ... Belt drive motor 7 ... Dielectric belt 7a: Sheet suction surface 8 ... Compression coil spring 9 ... Bush 10… Drive gear 11… Charging roller 12… Metal roller 13… AC power supply 14… Air suction section 15a ... Belt roller 15b ... Belt roller 16… Suction belt 16a ... Suction hole 16b… Sheet suction surface 17… Timing belt 18… Belt side plate 19… Belt side plate 20… Eccentric cam shaft 20a ... Eccentric cam 21 ... Gear 22… Duct lift motor 23… Duct 24 ... Suction fan 25… Sheet tray 26… Tray lifting motor 27… Link 28… Seat surface detection sensor 29 ... 30… Fan speed sensor 31… Paper type switching monitor 32 ... CPU 33… Conveyor roller pair 34… Sheet detection sensor 35… Automatic manuscript reader 36… Feeding device 37… Image processing equipment 38… Original reading section 39… Platen belt 40… Platen 41… Ejection tray 42 ... Photosensitive drum 43 ... Development Department 44… Transcription path 45… Transfer separation unit 46… Transport section 47… Fixing device 48… Suction belt unit 49… Air suction section 50… Suction drum 50a ... Circular hole 50b… Sheet suction surface

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65H 5/06 B65H 5/06 M 5/22 5/22 BCF term (reference) 3F049 AA01 BA04 CA06 DB04 EA14 FB05 LA02 LA05 LA07 LB03 3F101 LA02 LA05 LA06 LB03 3F343 FA02 FB03 FB04 FC01 GA01 GB01 GC01 GD01 HA16 HB04 HD16 JB05 JB06 KB04 KB05 LA04 LA14 LC08 LC11

Claims (12)

[Claims] 1. A sheet conveying device for adsorbing and conveying a sheet, comprising: a first adsorption surface arranged at a position corresponding to an end surface of the sheet; and a second adsorption surface arranged at a position corresponding to a center surface of the sheet. And a sheet conveying device. 2. The sheet conveying apparatus according to claim 1, wherein the first suction surface and the second suction surface are individually movable in the contact and separation directions with respect to the sheet. 3. The end surface of the sheet is within a region of 30 mm or less from an end which is a sheet boundary toward the center of the sheet, and the center face of the sheet is within a region other than the end face of the sheet. The sheet conveying device according to claim 1. 4. The sheet conveying apparatus according to claim 1, wherein the suction force N1 of the first suction surface and the suction force N2 of the second suction surface have a relationship of N1> N2. 5. The sheet conveying apparatus according to claim 1, wherein the first suction surface attracts the sheet before the second suction surface. 6. A sheet conveying speed V1 on the first suction surface and a sheet conveying speed V2 on the second suction surface.
Is in a relationship of V1 <V2.
The sheet conveying device described. 7. A detection means for detecting the type, thickness, or use environment of the sheet is provided, and depending on the detection result of the detection means, the first suction surface and the second suction surface in the contact and separation direction with respect to the sheet. The sheet conveying apparatus according to claim 1, wherein the movement amount is determined. 8. The sheet conveying apparatus according to claim 1, wherein the first suction surface is an air suction system that sucks a sheet by setting a negative pressure to the suction surface. 9. The sheet conveying apparatus according to claim 8, wherein the first suction surface is an endless belt having a plurality of holes. 10. The sheet conveying apparatus according to claim 8, wherein the first suction surface is a cylindrical roller having a plurality of holes. 11. The second attraction surface is an electrostatic attraction method in which a voltage is applied to a dielectric to generate an electric charge on a sheet in contact with the dielectric to electrostatically attract the sheet. The sheet conveying device according to claim 1, wherein 12. An image processing apparatus comprising the sheet conveying device according to claim 1 and an image reading unit or an image forming unit.