JPH01271350A - Sheet conveyor - Google Patents

Abstract

PURPOSE:To prevent a sheet from being smudged because of toner sticking by making the toner stuck to a presser roll contact with a cleaning part and cleaning it up, in a sheet conveyor which conveys the sheet transferred with a toner image in a copying machine or the like to a fixing unit. CONSTITUTION:When a sheet S is conveyed to an interval between a conveyor roller 1 and a presser roll 13, this roll 13 is pushed upward by strength of stiffness in this sheet S, whereby a space part A is formed in space between the back of the sheet S and a cleaning part 3, and both are held in a noncontact state. On the other hand, the presser roll 13 is energized by a surface of the sheet S, pressing this sheet S to a conveying part 4, and thereby conveyability in the conveyor roller 1 is thus improved. At this time, a pressing tooth of the presser roll 13 comes into contact with the surface of the sheet S. Consequently, if the sheet S is one that holds a toner on the surface electrostatically, the pressing tooth contacts with the toner and holds it. Next, when the sheet S is passed through, the pressing tooth is made contact with the cleaning part 3 and cleaned up.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paper conveyance device that conveys paper.

(Prior Art) Conventionally, as shown in FIG. 4, one of the paper conveyance devices has a rotationally driven conveyance roller (24) and a plurality of presser teeth (26) around the circumference. 26) is in pressure contact with the outer periphery of the conveyance roller (24). A device that transports paper while holding it there has been proposed.

For example, as shown in the figure, this paper conveying device is used in an image forming apparatus such as a copying machine or a printer, at a paper feeding section (21).
A sheet of paper (S) is supplied from the printer and has a toner image transferred to its surface (upper surface) in a transfer area (X) where an electrostatic latent image carrier (20) and a transfer charger (22) face each other, and is conveyed to a fixing device (23). used as a means to

(Problem to be Solved by the Invention) However, in the paper conveying device, the presser teeth (26)
The leading edge of the paper comes into contact with the unfixed toner electrostatically held on the paper surface and holds the toner.

For this reason, toner accumulates on the presser teeth (25) and falls onto the surface of the paper (S) due to some kind of vibration, staining the image surface, or transfers from the presser teeth (25) to the conveyance roller (24). There was a problem in that the toner adhered to the back surface of the paper (S) and stained it.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and will be described with reference to FIGS. 1 and 2 showing one embodiment. A presser wheel (13) having a presser wheel (14) is urged against the outer circumference of the conveyance roller (1).
In a paper transport device that transports the paper (S) while holding it between the presser wheel (13) and the presser wheel (13), an area of a predetermined width including a portion of the transport roller (1) that is in contact with the presser teeth (14), Areas located on both sides of the area (transport unit) (4), (
4) is provided with a presser tooth cleaning portion (3) having a smaller diameter.

(Function) In the above configuration, as shown in FIG. 3, when the sheet (S) is conveyed between the conveyance roller (1) and the presser wheel (13), Presser wheel (13)
) is pushed upward, and the back side of the paper (S) and the cleaning section (
3), a space (A) is formed between the two and the two are kept in a non-contact state.

On the other hand, the presser wheel (13) is urged against the surface of the paper (S),
The paper (S) is pressed against the conveyance units (4), (4), and the conveyance tendency of the conveyance roller (1) is adjusted.

At this time, the presser foot 1 (14) of the presser wheel (13) is
) in contact with the surface.

Therefore, if the paper (S) has toner electrostatically held on its surface, the presser teeth (14) contact and hold the toner.

Next, when the paper (S) passes through and returns to the state shown in FIG. 1, the presser teeth (14) are brought into contact with the cleaning section (3) and cleaned.

Therefore, even if the paper (S) is conveyed again, the toner from the presser m (14) will not be transferred to the surface of the paper and stain it. In addition, since the back side of the paper (S) is held in a non-contact state with the cleaning section (3) as described above, the cleaning section (3)
There is no chance that the toner will transfer and stain the back side.

(Example) The present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the conveyance roller (1) connects the cleaning section (3) and the conveyance section (4) to the support shaft (2).
).

(4) is provided so as to be held between the cleaning section (3).
Support portions (
6) and (6) are rotatably held via bearings (7) and (7), and are rotationally driven via a drive shaft (8).

The cleaning section (3) has a width of 2 to 5 mm and is made of a porous material such as sponge or felt.
) is made of rubber having a large coefficient of friction with paper, such as CRB rubber, and its outer diameter is larger than that of the cleaning part (3), and a step (H) is formed between the two.

A wall (9) is formed above the conveyance roller (1), on which an arm (11) is rotatably supported via a shaft (10) parallel to the conveyance roller (1). Similarly, the presser wheel (
13) is rotatably held.

The arm (11) is biased in the direction of arrow (a) in FIG. 2 via a spring (16) attached to the main body (5), and presser teeth (
The tip (15) of the cleaning part (14) is brought into light contact with the outer periphery of the cleaning part (3).

In the above configuration, the conveyance roller (1) is connected to the drive shaft (8).
When the presser wheel (13) is rotated through the cleaning section (3), the presser wheel (13) that is in contact with the cleaning section (3) rotates while being driven, and its tip (15) is cleaned by the cleaning section (13).

Next, as shown in FIG. At the part facing the cleaning part (3), the spring (
16), the presser wheel (13) is moved slightly upward against the urging force of
A non-contact state is established via .

On the other hand, the paper (S) is conveyed by the presser wheel (13) by the urging force of the spring (16) to the conveyance section (4) of the conveyance roller (1).

(4), the paper (S) and the transport section (4), (4)
) and the paper (S) increases as the frictional force with the transport roller (
The rotation in step 1) allows for good conveyance. Also, presser wheel (1
3) rotates while contacting the surface of the paper (S).

Here, as shown in FIG. 4, the paper transport device of this embodiment transports the paper (S) with unfixed toner electrostatically held on its surface to the fixing device (23) in a copying machine or the like. When used as a product, unfixed toner is retained on the surface of the paper (S) that has passed through the transfer area (X), and the tip (15) of the pushing teeth (14) comes into contact with this.

This presser foot! (14) is transferred again to the paper (S), but the presser foot m(1
Since the area of the tip (4) is extremely small, the amount of toner is small, and most of the toner is retained near the presser tooth tip (15).

However, when the paper (S) finishes passing between the conveyance roller (1) and the presser wheel (13), the presser teeth (14) come into contact with the cleaning section (3) again.

Here, as mentioned above, since the cleaning part (3) is formed of a porous soft material, the area where the tip (15) of the presser wheel (13) contacts the cleaning part (3) is the same as that of the paper (S). The toner held around the tip (15), which is wider than the contact area, is also well removed and cleaned by the cleaning section (3).

Therefore, even if the paper (S) is later conveyed between the conveyance roller (1) and the presser wheel (13), toner will not adhere to the front and back surfaces of the sheet (S).

In addition, in the above embodiment, the presser wheel (13) has a spring (1
6), the cleaning unit (3) is brought into contact with the paper (S) in an upright position. shape, fit both ends of the shaft (12) here, and press the presser wheel (13).
) is supported vertically movably, and the presser wheel (13) and shaft (12
) may cause the presser wheel tip (15) to come into contact with the cleaning section (3).

Further, in the above embodiment, a case has been described in which the paper conveyance device according to the present invention is applied to a means for conveying paper from the transfer area (X) to the fixing device (23) in an image forming apparatus such as a copying machine. Its application is not limited to this.

(Effects of the Invention) As is clear from the above explanation, according to the paper conveying device according to the present invention, the toner adhering to the tip of the presser wheel is removed by the cleaning section, so that the surface of the paper that comes into contact with the tip of the presser wheel is removed. Contamination is reduced.

Furthermore, since the cleaning section that collects the toner from the presser wheel is cut off from contact with the paper by the conveyance section having a larger diameter than this, toner does not adhere to the back surface of the paper and cause it to become dirty.

[Brief explanation of the drawing]

Figure 1 is a front view of the paper conveyance device, and Figure 2 is the ■- in Figure 1.
3 is a front view showing the paper transport state, and FIG. 4 is a sectional view showing the paper transport state of the image forming apparatus. ■... Conveyance roller, 3... Cleaning section, 4... Conveyance section, 11... Arm, 13... Presser wheel, 14... Presser tooth, 15... Tip, 16... Spring , S...Paper. Patent applicant Minolta Camera Co., Ltd. Agent Patent attorney Aoyama Aoyama and one other person Figure 1 Figure 2

Claims (1)

[Claims] (1) In a paper conveyance device in which a presser wheel having a plurality of presser teeth around the periphery is urged against an outer peripheral portion of a conveyance roller, and the sheet is conveyed while being held between the conveyance roller and the presser wheel, the A paper conveyance device characterized in that a presser tooth cleaning portion having a smaller diameter than areas located on both sides of the region is provided in a region of a predetermined width including a portion in contact with the presser teeth.