JP3751758B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like, and in particular, improved paper discharge performance so that a transfer paper on which an image has been formed can be discharged without being scattered on a paper discharge portion on the image forming portion. About things.
[0002]
[Prior art and problems to be solved by the invention]
In the case of an image forming apparatus such as a copying machine that does not pass the transfer paper linearly, the transfer paper is bent many times before the paper is discharged, and the transfer paper is likely to be curled. In particular, in a color copying machine or the like in which transfer paper is wound around a drum-like body at the time of transfer and performs transfer a plurality of times, the transfer paper tends to lose its moisture and become hard, so that it tends to curl when the amount of transferred toner is large.
[0003]
When the curled transfer paper is discharged to the paper discharge unit and stacked, the transfer paper is not neatly stacked in a bundle due to curling and often becomes loose. Also, in an apparatus in which a paper discharge unit is formed between the image forming unit and the image reading unit above it, referred to as an in-cylinder paper discharge type, the upper part of the paper discharge unit is separated by the image reading unit. The paper section becomes a relatively small space, and when the curled transfer paper is discharged there, the transfer paper will be present in the paper discharge section as soon as the number of discharged sheets is small, and the subsequent transfer paper will be smooth It is easy to curl near the paper discharge port or to go in any direction without being discharged. In any case, in the state where the stack state as described above is being formed, there arises a problem that all or a part of the transfer paper subsequently discharged is likely to jump out of the paper discharge unit. In such a state, for example, when there is a post-processing device in the subsequent stage, there is a problem that it is not possible to smoothly shift to the post-processing.
[0004]
Various proposals have been made to solve such a problem. For example, as in the image forming apparatus disclosed in Japanese Patent Laid-Open No. 7-309503, a paper discharge unit that discharges transfer paper after image formation is used. Some of them are provided above the discharged transfer paper and provided with a member for preventing the transfer paper from popping out. In this technique, an elastic sheet made of a resin film is disposed on an intermediate tray on which transfer paper is once stacked at the time of double-sided image formation, and is pressed in a direction to cancel curl generated on the transfer paper. However, in this technique, as a means for dealing with discharge and stacking of a plurality of size transfer sheets, a plurality of elastic sheets are provided for each transfer sheet size, and a mechanism for rotating each elastic sheet is required. Therefore, there is a problem that the structure is complicated and the cost tends to be high.
[0005]
Therefore, the present invention can cope with a plurality of size transfer papers with a single pop-out prevention means, and even when curl is generated on the discharged transfer paper, it can be stacked neatly without being scattered or scattered. An object of the present invention is to provide a simple and low-cost image forming apparatus.
[0006]
[Means for Solving the Problems]
According to a first aspect of the image forming apparatus of the present invention, in order to achieve the above object, a surface on which the discharged transfer paper is stacked in a paper discharge unit that discharges and stacks the transfer paper after the image formation. Has a surface on the upstream side in the paper discharge direction of the transfer paper and a surface on the downstream side in the paper discharge direction of the transfer paper and having a slope different from that on the upstream side. A member for preventing the transfer paper from popping out is provided above the transfer paper, and the pop-out prevention member is composed of two sheet-like members, and the base end of one sheet-like member is used as the paper discharge unit. The transfer sheet is attached to the upper side of the transfer sheet so as to be pivotable in the vertical direction, and has a member for pressing the transfer sheet stacked on the upstream surface on the leading end side. The base end of the other sheet-like member is connected to the front end so as to be rotatable in the vertical direction, In a square front end side of the sheet-like member, Ri Na has a member for holding the transfer sheet is stacked on the surface of the downstream member for pressing the transfer sheet are each rubber piece, above the rubber piece The cross-sectional shape along the discharge direction of the transfer paper is an arc shape, and the arc-shaped surface is attached downward, and a part of the attachment portion of the rubber piece of the two sheet-like members is attached to the rubber piece. let run onto the arcuate surfaces and said Rukoto such by.
[0007]
According to the second aspect of the present invention, there is provided an image forming apparatus in which a sheet discharge unit for discharging transfer paper after image formation is provided with a member positioned above the discharged transfer paper to prevent the transfer paper from popping out. In
The pop-out prevention member is composed of two sheet-like members,
The base end of one sheet-like member is attached to the discharge source side of the transfer paper onto the paper discharge unit so as to be pivotable in the vertical direction, and the front end side is extended to the paper discharge unit. The base end of the other sheet-like member is connected to the tip of the member so as to be rotatable in the vertical direction,
The leading end side of the other sheet-like member is further extended on the paper discharge unit to become a free end,
A rubber piece is attached to each of the lower surfaces of the two sheet-like members on the front end side in the discharge direction of the transfer paper, the cross-sectional shape of the rubber piece along the discharge direction of the transfer paper is an arc, and the arc-shaped surface is It is attached downward, and a part of the attachment part of the rubber piece of the two sheet-like members is run on an arc surface of the rubber piece .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a partial front view showing an embodiment of an image forming apparatus according to the present invention. In the figure, reference numeral 1 denotes an image forming unit, a paper feeding unit 2 is provided below the image forming unit, an image reading unit 3 is provided above the image forming unit, and a space between the image forming unit 1 and the image reading unit 3 is a paper discharge unit 4. A post-processing device 5 is provided so as to be connected to the paper discharge unit 4. In this apparatus, a target image is formed by the image forming unit 1 on the transfer paper fed from the paper feeding unit 2, and then the image is fixed on the transfer paper by a fixing unit (not shown). The transfer paper P is discharged to the paper discharge unit 4 via 6 and stacked. A pop-out prevention member 7 is provided on the paper discharge unit 4. In the figure, reference numeral 4a denotes a stopper having a substantially triangular cross section, which can be rotated to the post-processing device 5 side.
[0013]
2 is a perspective view of the pop-out preventing member 7, and FIG. 3 is an exploded perspective view of the same. 4 is a front view of the pop-out prevention member 7 attached, and FIG. 5 is a front view showing the positional relationship between the pop-out prevention member 7 and the transfer paper when the transfer paper discharge is started. The pop-out prevention member 7 of this embodiment is composed of two flexible PET sheets 8 and 9, two semi-cylindrical rubber pieces 10 and 11, and two thin adhesive tapes 12 and 13. Thus, the rubber pieces 10 and 11 serve as stoppers for the transfer paper P discharged onto the paper discharge unit 4 and serve to prevent the transfer paper P from curling and to prevent variations and pop-outs. For this reason, in the illustrated embodiment, the entire length of the pop-out preventing member 7 is substantially the entire length in the transfer paper discharge direction of the paper discharge unit 4 so that the transfer paper of all sizes to be discharged can be pressed. . In the figure, 14 and 15 are double-sided tapes for attaching the rubber pieces 10 and 11 to the sheets 8 and 9.
[0014]
The two PET sheets 8 and 9 have a base end portion 8a, which is wider than one of the sheets 8, attached to the relay conveyance device 6 by an adhesive tape 12 so as to be rotatable, and a narrow end portion 8b. The base end side of the other sheet 9 is abutted on the side, and the adhesive tape 13 is rotatably attached to each other, and the rubber piece 11 side at the front end of the sheet 9 is a free end. FIG. 5 shows the rotation direction of the sheets 8 and 9 with arrows. The sheet 9 has substantially the same width as the front end portion 8 b of the sheet 8.
[0015]
One sheet 8 has a base end portion 8a attached to the relay conveyance device 6 with a width (L1) wider than the width (L2) of the front end portion 8b (L1> L2). The length (L3) is shorter than the distance (L4) from the position where the leading edge of the transfer paper P discharged from the relay conveyance device 6 first contacts the sheet 8 to the position closer to the base end side (L4). L3 <L4).
[0016]
FIG. 6 is a perspective view showing a state where the rubber pieces 10 and 11 are attached to the sheets 8 and 9, and FIG. 7 is a front view of the same. 6 and 7 show only the attachment of the rubber piece 10 to the sheet 8, the structure and form of attachment of the rubber piece 11 to the sheet 9 are the same. As shown in the drawing, the leading end of the leading end portion 8b of the sheet 8 is divided into three parts, and the central T-shaped portion 8t is formed so as to protrude from both side portions 8s and 8s. Further, the width of the T-shaped portion 8t is the same as the width of the leading end portion 8b of the sheet 8 in order to ensure the adhesive strength with the rubber piece 10, and the length (L5) is shorter than the length (L6) of the rubber piece 10. When the rubber piece 10 is pasted in a state where the T-shaped portion 8t and the edge of the rubber piece 10 are aligned, the rubber piece 10 protrudes toward the side portions 8s from the T-shaped portion 8t. The front ends of both side portions 8s ride on the cylindrical surface of the rubber piece 10. The ride on the ends of the side portions 8s smoothens the transfer paper P onto the arc surface of the rubber piece 10. In the following description, the sheet 9 will be described with the central T-shaped portion being denoted by 9t and the portions on both sides being denoted by 9s.
[0017]
A discharge mode of the transfer paper P in this embodiment will be described with reference to FIGS. 4, 5, and 8 to 11. In the following, as shown in FIGS. 8 to 10, the tip of the B5 vertical size transfer paper discharged onto the paper discharge unit 4 is slightly past the position of the rubber piece 10, and the A4 vertical size transfer paper is used. Although the case where the length of the sheets 8 and 9 is set so that the tip of the rubber piece 11 slightly passes the position of the rubber piece 11 will be described, of course, the present invention is not limited to this setting.
[0018]
As shown in FIG. 4, when the transfer paper P has not been discharged, the rubber pieces 10 and 11 are so weighted that the sheets 8 and 9 are substantially along the upper surface of the paper discharge unit 4. , 11 are in contact with the upper surface of the paper discharge unit 4. When the discharge of the transfer paper P starts, first, as shown in FIG. 5, the transfer paper P that has started to be discharged from the relay conveyance device 6 proceeds slightly straight upward in the discharge direction (indicated by an arrow in the figure). .), The leading end abuts on the base end side of the front end portion 8b of the sheet 8 (slightly more on the front end side than the wide base end portion 8a as described above), pushes up the base end portion 8a of the sheet 8 upward, It is further discharged while curving. At this time, the front end portion 8b of the sheet 8 also tries to move upward. However, since no external force is applied to the sheet 9, the sheet 9 is kept in its original state only by bending the adhesive tape 13, so that the sheet 8 The rubber piece 10 provided at the leading end 8b maintains the position of the upper surface of the paper discharge unit 4, and the sheet 8 is curved like a bow. The leading end side of the transfer paper P in the discharge direction moves along the curvature of the sheet 8. Since the sheet 8 is made of PET with no irregularities on the surface, even if the leading edge of the transfer paper P comes into contact with the sheet 8 in this way, there is no resistance, and paper jams, stack failures, and the like are unlikely to occur.
[0019]
When the leading edge of the transfer paper P hits both side portions 8 s of the leading end portion 8 b of the sheet 8, the transfer paper P enters the lower side of the cylindrical surface of the rubber piece 10 while being guided by the both side portions 8 s. Pressed. When the transfer paper P is B5 vertical size, the entire sheet is discharged onto the paper discharge unit 4 in this state, and is sequentially stacked properly without being scattered or ejected from the paper discharge unit 4 (see FIG. 8).
[0020]
When the transfer paper P is A4 vertical size, the leading edge further advances, and moves obliquely upward along the slope of the stopper 4a, and is guided by both side portions 9s at the leading edge of the sheet 9, and below the cylindrical surface of the rubber piece 11. The curl at the tip is pressed by the rubber piece 11, and the whole is discharged onto the paper discharge unit 4 in this state, and is properly stacked sequentially without being scattered or jumping out of the paper discharge unit 4 ( (See FIG. 9). Even if the leading end of the transfer paper P in the discharge direction is in sliding contact with the lower surface of the sheet 9, the sheet 9 is also made of PET with no irregularities on the surface, so this contact does not become resistance, and paper jams, stack failures, etc. are unlikely to occur. .
[0021]
When the transfer paper P is A3 or DLT size, the leading end further advances from the lower side of the rubber piece 11, and the stopper 4a (the stopper 4a is rotated toward the post-processing device 5 as shown in FIG. 10). ), The front end protrudes from the paper discharge section 4 while being guided by the surface which is normally the bottom surface, and is completely discharged. In this state, the transfer paper P is pressed at two positions in the middle by rubber pieces 10 and 11 with a gap therebetween. That is, in this case, the curl at the leading edge of the transfer paper P cannot be pressed, but because the rubber pieces 10 and 11 are pressed at two locations, even large-size paper can be scattered or ejected from the paper discharge unit 4. It is stacked properly sequentially.
[0022]
During the above operation, there is a possibility that the sheets 8 and 9 are turned up and twisted as shown in FIG. 11 by being pushed up by the transfer paper P to be discharged. Since it is wider than the portion 8b, and the contact position of the transfer paper P is on the narrow end portion 8b side, the resilience is strong against turning. Further, since the leading end 8b and the sheet 9 of the sheet 8 are narrow, the rotation due to the contact with the transfer paper P is prevented, and an excessive resistance is hardly given to the leading end of the transfer paper P. The paper is discharged smoothly.
[0023]
In addition, in order to attach the sheets 8 and 9 so that rotation is possible, in the above-mentioned embodiment, although an adhesive tape is used, it is needless to say that other means may be used as long as rotation is ensured.
[0024]
【Example】
As a result of experiments by the inventors of the present application, when the thickness of the sheets 8 and 9 is about 0.125 mm, the transfer paper having no stiffness such as thin paper can sufficiently exhibit the above-described functions. Further, since the sheets 8 and 9 themselves are sufficiently stiff, even if they are turned as shown in FIG. 11 by an external force, for example, they naturally return to the original state. If the thickness of the sheets 8 and 9 is made too thin, the sheet 8 will be turned up by an external force, and it will be difficult to return to the original state. If it is regulated, a stack failure may occur. Therefore, it is necessary to select an appropriate material and thickness of the sheets 8 and 9 depending on the transfer paper to be discharged. Generally, the sheet 8 and 9 are made of PET and have a thickness of about 0.125 mm. Would be enough.
[0025]
【The invention's effect】
In the image forming apparatus according to the first aspect, as described above, the pop-out prevention member is constituted by two sheet-like members, and the base end of one of the sheet-like members is discharged onto the paper discharge unit. It is attached to the original side so that it can be pivoted in the vertical direction, and the leading end is extended above the paper discharge unit, and the base end is connected to the tip of one sheet-like member so that it can pivot in the vertical direction. A simple structure in which the front end side of the member is further extended on the paper discharge unit to become a free end, and the transferred paper is curled by pressing the discharged transfer paper from above without increasing the cost. However, it has the effect of being able to stack properly while preventing popping out without being scattered or scattered. Further, even if there are a plurality of sizes of transfer paper to be used, the sheet-like member can be dealt with simply by extending the sheet-like member substantially over the entire length in the paper discharge direction of the paper discharge section or by making the length that can hold the longest transfer paper. There is also an effect.
[0026]
Since the image forming apparatus according to claim 2 has rubber pieces attached to the lower surfaces of the two sheet-like members as described above, in addition to the above-mentioned common effect, the transfer in which the rubber pieces are discharged. In addition to improving the stackability by pressing the paper from above, if the rubber piece has an appropriate weight, it is pushed by the movement of the transfer paper and the sheet-like member is pushed away from the paper discharge unit. There is an effect that comes to prevent.
[0027]
In the image forming apparatus according to the third aspect, as described above, the cross-sectional shape of the rubber piece is an arc shape, and the arc-shaped surface is attached downward. There is an effect that a stack defect or a paper jam due to catching of the leading edge of the paper does not occur.
[0028]
As described above, the image forming apparatus according to claim 4 has a part of the two sheet-like members mounted on the arc surface of the rubber piece. There is an effect that the transfer paper can be smoothly guided to the arcuate surface.
[0029]
As described above, the image forming apparatus according to claim 5 is formed by forming the sheet-like member with a flexible material. Therefore, in addition to the common effect, the sheet-like member is brought into contact with the transfer paper. Is bent and rotated, and the transfer paper can be discharged more smoothly.
[0030]
In the image forming apparatus according to the sixth aspect, as described above, the width of one of the sheet-like members is wide on the transfer paper discharge source side and narrow on the leading end side. Not only does the force to return the sheet to the original state become stronger, but the sheet width is narrow on the discharge destination side, so that the rotation is improved, and there is little extra resistance on the transfer paper tip. Further, the transfer paper can be discharged smoothly.
[Brief description of the drawings]
FIG. 1 is a partial front view showing an embodiment of an image forming apparatus according to the present invention.
2 is a perspective view of a pop-out prevention member of the image forming apparatus in FIG. 1. FIG.
FIG. 3 is an exploded perspective view of the pop-out prevention member.
FIG. 4 is a front view showing a state in which the pop-out prevention member is similarly attached.
FIG. 5 is a front view showing a positional relationship between a pop-out preventing member and transfer paper at the start of transfer paper discharge.
FIG. 6 is a perspective view showing a state in which a rubber piece is attached to a sheet constituting a pop-out preventing member.
FIG. 7 is a front view of the same.
FIG. 8 is a front view showing a stack state when the transfer paper is B5 vertical size.
FIG. 9 is a front view showing a stack state when the transfer paper is A4 vertical size.
FIG. 10 is a front view showing a stack state when the transfer paper is A3 size or the like.
FIG. 11 is a perspective view showing a state in which a sheet constituting the pop-out preventing member is twisted.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image formation part 2 Paper feed part 3 Image reading part 4 Paper discharge part 4a Stopper 5 Post-processing apparatus 6 Relay conveyance apparatus P Transfer paper 7 Pop-out prevention member 8, 9 PET sheet 8a Sheet base end part 8b Sheet tip Portions 8t, 9t T-shaped portion 8s of sheet, 9s Both side portions 10, 11 of rubber sheet 12, 13 Adhesive tape 14, 15 Double-sided tape

Claims (2)

The discharge paper stacking unit that discharges and stacks transfer paper after image formation has a surface on which the transferred transfer paper is stacked, an upstream surface in the paper discharge direction of the transfer paper, and discharge of the transfer paper on the surface. A surface downstream of the direction and having a slope different from that of the upstream surface,
A member for preventing the transfer paper from popping out is provided above the discharged transfer paper,
The pop-out prevention member is composed of two sheet-like members,
A base end of one sheet-like member is attached to the discharge source side of the transfer paper onto the discharge unit so as to be pivotable in the vertical direction, and the transfer paper stacked on the upstream surface is attached to the leading end side. Having a member to hold down,
Transfer that is connected to the leading end of the one sheet-like member so that the base end of the other sheet-like member can rotate in the vertical direction, and is stacked on the downstream side at the leading end side of the other sheet-like member Ri Na has a member for pressing the paper, a member, each rubber piece for pressing the transfer paper, the cross-sectional shape along the discharge direction of the transfer sheet of the rubber piece and arc-shaped, downward circular arc surfaces be attached towards the image forming apparatus characterized part of the mounting portion of the rubber strips of the two sheet-like members, the Rukoto such let me ride on arcuate surface of the rubber strip. In an image forming apparatus in which a discharge unit that discharges transfer paper after image formation is provided with a member that is located above the discharged transfer paper and prevents the transfer paper from popping out.
The pop-out prevention member is composed of two sheet-like members,
The base end of one sheet-like member is attached to the discharge source side of the transfer paper onto the paper discharge unit so as to be pivotable in the vertical direction, and the front end side is extended to the paper discharge unit. The base end of the other sheet-like member is connected to the tip of the member so as to be rotatable in the vertical direction
The leading end side of the other sheet-like member is further extended on the paper discharge unit to become a free end,
A rubber piece is attached to each of the lower surfaces of the two sheet-like members on the front end side in the discharge direction of the transfer paper, the cross-sectional shape of the rubber piece along the discharge direction of the transfer paper is an arc, and the arc-shaped surface is An image forming apparatus, wherein the image forming apparatus is mounted downward and a part of the rubber piece attachment portion of the two sheet-like members is mounted on an arc surface of the rubber piece .

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