JPH01145975A - Sheet material conveying device - Google Patents

Abstract

PURPOSE:To prevent production of a slack on a sheet material by a method wherein a first and a second flapper are disposed on the same plane extending approximately at right angles with a sheet material to be conveyed, and the second flapper is held in a manner to make contact with the first flapper. CONSTITUTION:For example, during single-sided duplication, a sheet material on which a picture is formed by the passage of the sheet material through a first conveyance passage P1 enters through a first discharge roller 21 and a gap between a main and an auxiliary flapper 32 along a main flapper 31 shown by a solid line. the sheet material is moved toward a second discharge roller 22 on the second conveyance passage P2 as it pushes up the flapper 32 by a distance equivalent to the thickness of the sheet material. In this case, since all of a load exerted on the sheet material under gravity of the flapper 32 is supported by the flapper 31, the sheet material is conveyed approximately in a flat state without slacking in a waveform manner, and production of wrinkles and damage of a picture due to local excessive slide friction are prevented. Further, hooking of the sheet material by a corner part 31d at the tip of the flapper 31 can be reliably prevented from occurring during switch back.

Description

Detailed Description of the Invention B. Purpose of the Invention [Industrial Field of Application] The present invention is intended for use in sheet materials (copy paper, transfer paper,・Related to transport devices for printing paper, etc.)

More specifically, the first section is disposed at a branch point of the sheet material conveyance path and is capable of selectively switching the conveyance direction of the sheet material being conveyed.
Sheet material conveyance path switching means comprising a flapper and a second flapper disposed near the first flapper to switch back the sheet material that has passed by the first flapper and guide it to another sheet material conveyance path. The present invention relates to a sheet material conveying device equipped with the following.

[Conventional technology]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet material conveying device in an image forming apparatus configured to form multiple images and double-sided images on a sheet material such as transfer paper will be described below as an example.

A copying apparatus as shown in FIG. 6 has already been proposed as an image forming apparatus as described above.

In the figure, 1 is a main body of the apparatus, and an image forming section (copying section) A is provided approximately in the center of the main body 1. The image forming section A includes a drum-shaped (cylindrical) photoconductor 2 that rotates at a predetermined circumferential speed in the direction of the arrow in the figure, a primary charger 3 disposed around the photoconductor 2, and a charger 2 containing toner of different colors. It consists of two developing devices 4a and 4b, a transfer charger 5, a separation charger 611, a cleaner 7, and the like.

A fixed document table 8 made of a transparent glass plate or the like is provided at the upper part of the apparatus main body 1. A document O is placed on the document table 8 with the image side to be copied facing downward, and a document pressure plate 9 is attached from above. It is set by covering it.

The lower side of the document table 8 includes a light source 1o for illuminating the document, a movable mirror 11a-1ies, an imaging lens 12, and fixed mirrors 13a to 1ies.
An image exposure optical system consisting of 13c is provided, and the photoreceptor 2, which has been uniformly charged by the primary charger 3, is image-formed and exposed by the optical system to the light reflected from the document surface. An electrostatic latent image is formed. The electrostatic latent image is
a or 4b, and a toner image to be transferred to a sheet material such as transfer paper is formed on the photoreceptor 2.

On the other hand, the sheet material S is stored in two feeding cassettes 14a111.
4b by the feeding rollers 15a-15b, and the registration roller 1
It is transported between 8018 and 8018. Next, the sheet material S is fed by the registration roller 18 between the photoreceptor 2 and the transfer charger 5 in the image forming section A at a predetermined timing, and the transfer charger 5 charges the photoreceptor 2 on the photoreceptor 2. After the toner image is transferred onto the sheet material, it is separated by a separation charger 6. The separated sheet material is then conveyed to a fixing device 20 by a conveying device 19 having a plurality of conveying rollers 19a.
In the case of normal one-sided copying, the image is directly ejected onto a take-up tray 23 outside the main body of the apparatus via a first ejection roller 21 and a second ejection roller 22 which can be rotated in forward and reverse directions.

A sheet material conveyance path (hereinafter referred to as the first conveyance path) PL from the registration roller 18 to the first discharge roller 21 via the image forming section A and the fixing device 20, etc., and a sheet material conveyance path PL from the second discharge roller 22 to the discharge tray 23. When performing multiple copying or double-sided copying, the sheet material on which the image has been formed after passing through the first transporting path P1 is again passed through registration rollers between the sheet material transporting path (hereinafter referred to as the second transporting path) P2. 18.1
A third conveyance path P3 leading between the sheet materials 8 and 8 is provided, and the third conveyance path P3 is composed of a large number of sheet material conveyance rollers 24 to 26 and guide members 27 to 30.

In addition, from the first conveyance path P1 to the second and third conveyance paths P2 and P
As shown in FIGS. 6 and 7, a first flapper (hereinafter referred to as "main flapper") 3 is located between the first and second discharge rollers 21 and 22, which is the branching point for the sheet material transport direction.
1 and a second flapper (hereinafter referred to as an auxiliary flapper) 32 are provided. 33 is the first and second discharge roller 2
This is a guide member provided between 1 and 22.

The above-mentioned main flapper 31 is attached to a support shaft 34 as shown in FIG.
The main flapper 31 can be moved between the solid line position and the chain line position as shown in FIGS. can be selectively switched to 36a is the plunger of the solenoid 36, and 37 is a return coil spring.

On the other hand, the auxiliary flapper 32 is rotatably supported by a support shaft 38 in the vicinity of each of the main flappers 31, as shown in FIG. Each of the auxiliary flappers 32 has an opening 33a provided in the guide member 33, as shown in FIG.
The locking protrusion 39 of the auxiliary flapper 32 is brought into contact with the opening edge thereof under a light load such as its own weight, so that the state shown in FIG. 7 is always maintained.

During normal one-sided copying, the main flapper 31 is at the solid line position in FIG. The sheet is conveyed between the two, and moves toward the second discharge roller 22 while pushing up the auxiliary flapper 32 with its conveying force. At the same time, the optical sensor 41 is activated by the detection arm 40 shown in FIG. 6, and the passage of the sheet material is detected, and the sheet material is ejected onto the tray 23 by the second ejection roller 22 forming the second conveyance path P2.

Also, during multiple copying, the main flapper 31 is activated by the solenoid 3.
6, the sheet material is switched to the position shown by the chain line in FIGS. 6 and 7, and the sheet material on which the image has been formed via the first conveyance path P1 in the same manner as described above is transferred from the first discharge roller 21 to the main flapper 31.
is guided to the third conveyance path P3. Then, the third
The sheet material guided to the conveyance path P3 is conveyed by conveyance rollers 24 to 26.
At the same time, the negative edge of the sheet material in the lateral direction (direction perpendicular to the transport direction) is aligned with a predetermined reference position by the transport roller 26 equipped with a lateral registration means. It is again introduced into the first transport path Pl from the upstream side of the registration rollers 18. and,
During the process of passing through the image forming section A and the fixing device 20, images of the same color or different colors are formed on the same surface of the sheet material as the image surface, and the main flapper 31 is moved to the solid line position in FIGS. 6 and 7. The sheet material is guided to the second conveyance path P2, and is discharged from the second discharge roller 22 onto the tray 23.

Furthermore, during double-sided copying, the main flapper 31 is placed at the solid line position in FIGS. 31 and 32, is once guided to the second conveyance path P2 side, and sent out toward the tray 23 by the second discharge roller 22. When the rear end of the sheet material passes the auxiliary flapper 32, the detection arm 40 and The operation of the optical sensor 41 causes the second discharge roller 22 to rotate in reverse, and the sheet material is transported back to the right in the figure. Then, the sheet material is transferred to the third conveyance path P along the guide surface 32a of the auxiliary flapper 32 on the second discharge roller 22 side and the guide surface 31a of the main flapper 31.
3 will be introduced as a switch pack. At this time, the main flapper 31 and the auxiliary flapper 32 are moved close to each other as shown in FIGS. 8 and 9 so that the sheet material does not get caught on the upper corner 31d of the guide surface 31a of the main flapper 31. In addition, as shown in FIG. There is.

Next, the sheet material introduced into the third conveyance path P3 is transferred to the conveyance rollers 24 to 26 as in the case of multiple copying described above.
and the registration roller 18 via the guide members 27 to 30.
The sheet is guided from the upstream side to the first conveyance path P1 again, and an image is formed on the sheet material surface opposite to the above-mentioned image surface by the image forming section A and the fixing device 20. 32, is guided to the second conveyance path P2, passes through the second discharge roller 22, and is discharged onto the tray 23.

[Problem that the invention seeks to solve]

As described above, in the conventional example, the main flapper 31 and the auxiliary flapper 32 are arranged in a staggered manner as shown by the solid line in FIG. The auxiliary flapper 32 is moved by pushing it upward depending on the strength of the waist, but the auxiliary flapper 3
Due to the load 2, the sheet material S is deformed to a considerable extent and becomes sagging in a wavy manner as shown by the chain line in FIG. This is especially true for weak sheet materials such as thin paper, where the amount of change (amount of slack) is large.

If abnormal sag occurs in the sheet material, it may lead to wrinkles, deformation such as streaks, or the sagging part may rub excessively against a part of the guide surface, causing the image surface etc. to rub off. Various negative effects occur on the sheet material, such as damage to the sheet material. In addition, from the perspective of transporting sheet materials, if the sheet material becomes sagging and deformed, the position of the sheet material may shift during transport, or if there is excessive slack, the sheet material may be attached to surrounding members such as guide members. It is also possible that something will get caught. Furthermore, when the sheet material is guided to the third conveyance path P3 along the guide surface 32a of the auxiliary flapper 32 due to the switchback operation described above, the slack of the sheet material protrudes toward the main flapper 31 side from the guide surface. , there is a risk that the main flapper 31 may get caught in the tip corner 31d.

The present invention aims to solve the above problems.

Summary: Structure of the Invention [Means for Solving the Problems] The present invention includes a first flapper that is disposed at a branch point of a sheet material conveyance path and is capable of selectively switching the conveyance direction of the sheet material being conveyed. and a second flapper disposed near the twelfth flapper to switch pack the sheet material that has passed by the first flapper and guide it to another sheet material transportation path. In the sheet material conveying device, the first flapper and the second flapper are arranged on the same plane substantially perpendicular to the sheet material being conveyed, and the second flapper is held in contact with the first flapper. It is characterized by the following.

[For production]

By arranging the first flapper and the 27th flapper on the same plane substantially perpendicular to the conveyed sheet material, and by bringing the second flapper into contact with the first flapper, the sheet material moves between the two flappers. It is possible to prevent the sheet material from sagging as described above when it passes through, and it is also possible to reliably prevent the sheet material from being caught on the tip corner of the first flapper during switch pack.

〔Example〕

1 to 3 show an embodiment of the present invention, in which a main flapper 31 as a first flapper and an auxiliary flapper 32 as a second flapper are arranged substantially perpendicular to the sheet material being conveyed. The auxiliary flapper 32 is arranged on a vertical plane, and the auxiliary flapper 32 is always brought into contact with the upper surface of the main flapper 31 under a light load such as its own weight. The other configurations are the same as in the case of the previous example, and the same members are given the same reference numerals and repeated explanations will be omitted.

With the above configuration, for example, during normal one-sided copying, the sheet material on which an image has been formed via the first conveyance path P1 can be
The first discharge roller 21 enters between the main flapper 31 and the auxiliary flapper 32 along the upper surface of the main flapper 31 arranged at the solid line position in FIG. Second discharge roller 22 on the road P2 side
move towards. At this time, all the load applied to the sheet material due to the weight of the auxiliary flapper 32 is supported by the main flapper 31, so as in the prior art, the sheet material supports the load of the auxiliary flapper 32 and forms a wave shape as shown by the chain line in FIG. The sheet material S is conveyed in a substantially flat state as shown in FIG. 3 without sagging, and damage to the image due to wrinkles or excessive local rubbing is prevented.

In addition, when the sheet material is switch-packed by the second discharge roller 22 of the second conveyance path P2 during double-sided copying and guided toward the third conveyance path P3 by the guide surface 32a of the auxiliary flapper 32, the sheet material is On the first discharge roller 21 side, the lower surface of the auxiliary flapper comes into contact with the tip corner 31d of the main flapper 31 and the tip corner does not protrude, so the sheet material is not caught and the sheet material is transferred to the third conveyance path P3. This allows for smooth guidance.

4 and 5 show a modification of the present invention, in which the guide surface 32a of the auxiliary flapper 32 and the main flapper 31
An example is shown in which the width d2 of the surfaces 32b and 32c facing the first discharge roller 21 is slightly wider than the width d1 of the main flapper 31.

With the above configuration, even if the position of the auxiliary flapper 32 relative to the main flapper 31 is slightly shifted due to manufacturing/assembly errors or backlash between the two flappers 31 and 32, the tip corner portion 31d of the main flapper 31 protrudes (is exposed). This makes it possible to more reliably prevent the sheet material from getting caught on the tip end corner 31d.

C. According to the present invention, as described in detail, the first flapper and the second
By arranging the flapper on the same plane that is substantially perpendicular to the sheet material to be conveyed, and by bringing the second flapper into contact with the first flapper, when the sheet material passes between both flappers, it is not possible to This prevents the sheet material from sagging, prevents wrinkles from forming in the sheet material, and prevents the image from rubbing off due to localized excessive rubbing of the sheet material against the flapper. This has the effect of reliably preventing the flapper from getting caught on the tip corner of the flapper.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a sheet material conveying device showing an embodiment of the present invention, Fig. 2 is a perspective view of the first and second flappers, Fig. 3 is a side view thereof, and Fig. 4 is a cross-sectional view of the second flapper. A perspective view showing a modified example, FIG. 5 a side view thereof, FIG. 6 a longitudinal sectional view of the image forming apparatus, FIG. 7 an enlarged view of a part thereof, and FIG. 8 a first and second
A perspective view of the flapper, and FIG. 9 is a side view thereof. Pi-P3 is a sheet material conveyance path, 31 is a first flapper (main flapper), 32 is a second flapper (auxiliary flapper), S
is sheet material.

Claims (1)

[Claims] 1. A first flapper disposed at a branch point of a sheet material conveyance path and capable of selectively switching the conveyance direction of the conveyed sheet material, and a first flapper disposed near the first flapper, In a sheet material conveyance device comprising a sheet material conveyance path switching means comprising a second flapper that switches back the sheet material passing by and guides it to another sheet material conveyance path, the first flapper and the second flapper are configured to A sheet material conveying device characterized in that the second flapper is arranged on the same plane substantially perpendicular to the sheet material being conveyed, and the second flapper is held in contact with the first flapper.