JPS60122657A - Transport apparatus - Google Patents

Abstract

PURPOSE:To suitably form a loop of a sheet material to accomplish normal transport of the sheet material by cancelling a sheet material retaining function in response to the time when the sheet material reaches a downstream turning out position to prevent bad effect of a retaining function upon the sheet material formed in a loop. CONSTITUTION:A sheet material 9 to which an image on an image bearing drum 1 has been transferred at a transfer portion (a) is fed out to the right with rotation of the drum 1. When the sheet material 9 passes a sensor 31', a suction fan 28 is operated by a control unit 30, and the sheet material 9 is drawn up to a transport belt 27 and brought into contact with the belt, so that the sheet material can pass a bending portion D of the transport belt smoothly. Subsequently, when the forward end of the sheet material reaches a sensor 31, a suction fan 28 is stopped by the control unit 30 immediately after the sheet material 9 advances into a nip portion (b) between fixing devices 7, 8. Accordingly, the contact between the sheet material 9 and the transport belt 27 is cut off to form a loop suitably, so that the desired end can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a means for adjusting the speed of each feed-out section or the feed-out direction between two feed-out portions located on the conveyance path of the sheet material and from which the sheet material is fed out by a rotating means. The present invention relates to a conveying means for sheet materials in which the difference does not interfere with the normal conveyance performance of the sheet materials.

For example, in conventional belt-type conveyance devices such as those used in copying machines, two delivery sections arranged in one stream and downstream on the conveyance path are arranged almost in a straight line, and both The distance between the feeding sections is determined by the fact that the sheet material is simultaneously engaged with the upstream nip section and the downstream nip section, so that slight differences in the feeding speed between the two feeding sections and the parallelism of the generatrix of both feeding means 9 In order to avoid imparting an irregular conveyance posture to the sheet material due to the difference, it is common to set the length to be larger than the length of the sheet material along the conveyance direction.

That is, in one example of a conventional copying machine shown in FIG. 1, an image-bearing drum 1 rotates in the direction of arrow A while temporarily supporting a ``color'' image formed by a photocopy image. A transfer charger 2 is disposed close to and opposite to the image bearing drum (on the left side in the figure).

The sheet-like transfer material 9 enters between the two and comes into contact with the image-bearing drum l at the transfer portion a, and the toner image on the tram 1- is transferred to the transfer material 9 by electrostatic action due to the charging of the transfer charger 2. be done. As the image bearing drum 1 rotates, the transfer material 9 passes through the transfer section a and is sent out to the right in the figure. Adjacent to this sending direction, conveying rollers 4a, 4b,
A conveying device C consisting of a conveying belt 3 which is passed over a drive roller 5 and driven in the direction of arrow B, and a suction fan 6 is arranged. The sheet-like transfer material 9 sent out from the transfer section a advances on the linear two-way transport surface 3a of the transport belt while being held by the negative pressure of the suction fan 6, and is composed of a fixing roller 7 and a pressure roller 8. image>if the toner image on the sheet-like transfer material 9 is fixed on the transfer paper. In the example of the conveyance device having the configuration described above, as shown in the figure, the transfer part a, the conveyor belt straight part 3a, and the nip part are almost straight lines, and the transfer part a and the nip part are The distance # is slightly larger than the sheet-like transfer material 9 passing through. This means that when the distance is smaller than the length along the conveyance direction of the sheet material used, while the 11a side portion of the sheet I-shaped transfer material 9 passes through the nip section, the sheet-like transfer is still carried out at the transfer section a. Material 9
This means that the rear part of the image bearing drum 1 and the fixing roller are transferred, which causes a slight difference in opening speed and a difference in the sending direction between the image bearing drum 1 and the fixing roller. Image carrying drum l-1]
If there is an error in the \1i line between the base I line of the transfer part a and the generatrix of the nip part of the fixing roller 7, an irregular acting force is exerted on the sheet-like transfer material 9 at the nip part, and this causes This is to prevent the sheet-like transfer material 9 itself from being affected by the above-mentioned influences by propagating the sheet-like transfer material 9 itself and promoting a regular transfer speed at the transfer portion a, thereby causing disturbances in the transferred image. In this case, since the distance is made larger than the length along the conveying direction of the sheet-like material used, the conveying device becomes larger and the copying machine itself inevitably becomes thicker.

In another conventional example shown in FIG. 2, a plurality of (two in this example) small-sized conveyance devices C, . In this example, if the conveyance path length from transfer section a to fixing section is set shorter than the conveyance direction length of the sheet-like transfer material to be used, the sheet material forms a downwardly convex loop, and Even if there is a speed difference or a difference in the generatrix direction with respect to the fixing unit, the acting force due to these can be somewhat absorbed by the loop portion of the sheet I/material.

However, since the sheet material is in close contact with the conveyor healds 3 and 3' by the suction fans 6 and 6', the flexibility of the sheet material cannot be utilized for one minute, and the above-mentioned speed difference and difference in the generatrix direction cannot be completely compensated for. It cannot be absorbed completely and the transferred image is affected.

The present invention eliminates the need to increase the size of the device as in the conventional example, and enables the device to be compact, and to avoid adverse effects on the image at the transfer section caused by the speed difference between the transfer section and the fixing section or the difference in the generatrix direction of the two sections. It is an object of the present invention to provide a sheet material conveying device that does not cause the above problems.

Please refer to FIGS. 3 and 4 showing a configuration diagram and a perspective view, respectively, of an embodiment of the conveying device according to the present invention.
The present invention will be explained below.

Drive rollers lla and llb constituting a conveying device arranged between a transfer section a consisting of an image bearing drum 1 and a transfer charger 2 and a nimp section of an image fixing device 7.8 are fixed to a drive shaft 12, and A driving force is applied from the main body of the device via the drive shaft 12 . The conveying roller 20 is rotatably supported by the support 15. Similarly, the presser roller 18 is attached to +b16, the transfer roller 22 is attached to the axis 17, the transfer roller 23 is attached to the axis j3, the presser roller 24 is attached to the axis 14, the transfer roller 25 is attached to the axis 15, and the transfer roller 22 is attached to the axis j3.
ea, 26b are connected to the shaft 18, and conveying rollers 32a, 33.
b is rotatably supported by a shaft 29 (see FIG. 3). The conveyor belt 27a includes a drive roller lla and a conveyor roller 2.
0, 22. On the outside of 28a and 32a, there is also a presser roller 2.
It is hung so that it is inside 1. transport bell) 2
? b is the driving roller 11b, the conveying rollers 23, 25, 2fib
and 27b and inside the presser roller 24. Conveying rollers 20, 22, 23, 25
．． The relative positional relationship between the presser rollers 21 and 24 is the same as in FIG. 3 and FIG. 4.

27b is arranged so as to be bent in a dogleg shape, and one of the conveyor belts is held down by a presser roller so that the other conveyor belt can maintain the conveyance path at the portion that enters the inside of the conveyance path. It is composed of In this embodiment, the length of the conveyance path is shorter than the length of the sheet material used in the conveyance direction, and the conveyor belt 27a,
The advancing speed of the image bearing drum 27b is set equal to the circumferential speed of the image bearing drum 1. A suction fan 28 is arranged inside the conveyor belts 27a and 27b, and the conveyor belts 27a and 27b are
, , J-, when the sheet material 9 is present at the conveyor bell) 27a, 2? Suction to side b. A sheet-like upstream passage detection sensor 31' is provided along the conveyance path of the conveyance device, and when the passage of the sheet material 9 is detected at this position, the suction fan control device 30 turns on the suction fan 28.
starts operating. Further, a sheet material downstream passage detection sensor 31 is disposed at the entrance of the fixing device, and when the sheet material 9 passes therethrough, a detection signal from the sheet material downstream passage detection sensor 31 is transmitted to the suction fan control device 30, and the downstream When the sheet material 9 reaches the nip portion from the passage detection sensor 31 with a time delay of 1 minute, the suction fan control device 30 stops the suction fan operating force. In other words, the front edge of the sheet material is located on the downstream side of the sheet material passage detection sensor 3.
1, the suction fan 28 is configured to stop only after the leading edge portion moves between the fixing unit rollers 7 and 8 and obtains a conveying force.

To describe the operation of the conveyance device according to the present invention configured as described above, the image on the image bearing drum l)H is transferred to the sheet material 9 in the transfer section a, and the sheet material 9 moves along with the rotation of the image bearing drum l. The sheet material 1 is sent out toward the direction and reaches the sheet material 1 flow passage detection sensor 31' of the conveyance device. At this time, the suction fan 28 starts operating by the suction fan control device 30 in response to the upstream passage signal, and the sheet material 9 is transported by the conveyor belt 27.
a.2? is attracted to b. already carrying bell) 27a,
27b is rotated by the driving force supplied from the main body of the copying machine, so the sheet material 9 is rotated by the conveyor belts 27a, 2.
7h and is conveyed. Even at the bending portion of the conveyor belt, the sheet material 9 contacts either one of the conveyor belts 27a or 27b to maintain the conveyance path, so that it passes smoothly through the bending portion of the conveyor belt.

Thereafter, the sheet material 9 is bent into a dogleg shape and conveyed along the conveyor belts 27a and 27b, and when its tip reaches the jetted flow passage sensor 31, the output signal of this sensor is sent to the suction fan control device ji130. Immediately after the sheet phase 9 enters the nip portion of the fixing device, the suction fan stops 11. Therefore, the transportation hell) 27a,
The frictional force between 27b and the sheet material 9 decreases, and the conveyor bell) 2? Although the conveying force on the sheet material 9 by a and 27b is low, since the leading edge of the sheet material 9 has entered the nip portion, the sheet material 9 is transported by the rotational force of the fixing roller 7 and the pressure roller 8. transported. After this, sheet material 9
Since the suction force of the suction fan 28 does not work, the conveyor belt 2 depends on its own strength. The contact is broken from a and 27b, but as shown in FIG. 3, a convex loop is formed. At this time, even if the rear end of the sheet material 9 is still being transferred in the transfer section a, even if there is a speed difference between the transfer section and the fixing section or a difference in the generatrix direction of the two, the sheet material 9 The loop of No. 9 absorbs those influences, and adverse effects on the transferred image are avoided.

Further, by making the feeding speed of the fixing section higher than the conveying speed, the conveying function of the conveying device can be achieved more reliably and efficiently according to the present invention. In PIJ, the pull-out impact exerted by the fixing section can be almost eliminated while the loop portion formed by the sheet material gradually decreases as the fixing speed increases.

The control system for the holding function of the holding means according to the present invention is the first
It is clear that the device is also applicable to the conventional type of apparatus shown in FIGS.

Since the present invention is configured as described above, it has the following effects.

(1) The IA feeding device can be compact and well-organized, and the overall size of the device equipped with it can be shortened.

(2) Set the sheet material to be conveyed on the conveyance path by
By forming a h f! This absorbs the tendency of deflection of the conveyed sheet material due to the difference in speed and the difference in the direction of the generatrix direction between the two conveying parts, and eliminates any unfavorable influence on image formation in the transfer part.

(3) By stopping the suction effect of the fan after the sheet material engages with the fixing site, the negative pressure exerted by the fan on the loop shape of the formed sheet material is avoided, and the sheet material naturally becomes flexible. Since the characteristics can be utilized to the fullest, an appropriate transfer image formation effect is guaranteed even in the defective state described in L (2).

[Brief explanation of drawings]

1 and 2 show first and second examples of a conventional conveying device, and FIGS. 3 and 4 show a configuration explanatory diagram and a perspective view of an embodiment of a conveying device according to the present invention. S・l...Image bearing drum 2...Transfer charger 7.8
... Fixing section 11 ... Drive rollers 20, 22, 23
．． 25, 26. 32... Conveying rollers 27a, 27b...
・Transport belt 28...Suction fan 31.31'...
Sheet material passage detection sensor 30 ... Suction fan control device cylinder 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1) A sheet material is placed on a conveying surface between delivery parts provided on the upstream side and downstream side of the conveying direction, and during the conveying operation, the sheet material is placed on the conveying surface. What is claimed is: 1. A conveying device having a holding means, characterized in that the sheet material holding function of the holding means is canceled in response to the sheet material reaching the downstream delivery site. 2) At least a means for detecting passage of the sheet material subsequent to the conveyance surface downstream and providing detection information, and a control means for canceling the holding function of the holding means in response to the detection information. A conveying device according to claim 1. 3) The conveyance device according to claim 1, wherein the upstream delivery section is an image transfer device, the downstream delivery section is an image fixing device, and the sheet material is an image transfer material. 4) The conveyance device according to claim 3, wherein the feed speed of the fixing device is higher than the conveyance speed of the conveyance device.