JPH04345448A - Structure of resist roller - Google Patents

Abstract

PURPOSE:To provide the structure of a resist roller which can prevent an attachment of a rubber refuse and the like on the surface of the resist roller and to improve the quality of a printing, as to the structure of a resist roller for uniforming the front ends of media used for a conveying mechanism to convey the media such as papers for cutform. CONSTITUTION:This resist roller 11 is used for conveying media, and furnishes a function to uniform the front ends of the media. The central part 12 of the resist roller 11 is made smaller then the other parts, and when a paper to which a rubber refuse or the like is attached is conveyed to the resist roller 11, the rubber refuse passes through the central part 12, and it is never deposited and adhered on the surface of the resist roller 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a registration roller for aligning the leading edge of a medium used in a conveyance mechanism for conveying a medium such as a cut sheet.

0002

2. Description of the Related Art FIG. 3 is a side view showing an outline of a conventional image recording apparatus. In the figure, 1 is a cylindrical registration roller, and 2 is a driven roller (rubber roller) that presses against the registration roller 1 with a registration pressure P. , 3 is a photosensitive drum, and 4 is a paper feeding section. Although not shown, a pre-charger, an optical unit for exposure, a developer, a transfer charger, an AC separation charger, a post-transfer charger, a cleaner, etc. are arranged around the photosensitive drum 3, although not shown.

[0003] Recording paper 100 is stored in a paper feed section 4, and is fed out by a pick roller 5 at a predetermined time. The fed paper 100 is sent to the registration roller 1 by the paper feeding means 6 and the feeding roller 7. Note that the paper feeding means 6 includes a feed belt 8 and a reverse roller 9, both of which are made of rubber, and reliably conveys the fed sheets 100 one by one.

On the other hand, the photosensitive drum 3 rotates clockwise in FIG. 3, and a toner image is formed on its surface in the following steps. That is, the surface of the photosensitive drum 3 is first uniformly charged by a pre-charger, and then exposed to light in a predetermined pattern (a pattern corresponding to image information) by an optical unit to form an electrostatic latent image. This electrostatic latent image is developed by a developing device to become a toner image.

After that, the toner image is transferred to the transfer position (photosensitive drum 3
However, as mentioned above, the paper sent to the registration roller 1 hits the registration roller 1 and the driven roller 2, buffers and stops (at this time, the leading edge of the paper is aligned), and then the paper is sent to the photosensitive drum 3. The paper is sent to a transfer position according to the speed, and a toner image is transferred onto the paper by a transfer device. The AC separator discharges an alternating current high voltage with a relatively high frequency onto the paper, thereby reducing the amount of charge and making the paper easier to peel off from the drum.

After the transfer has been completed, the surface of the photosensitive drum 3 is neutralized by a post-transfer static eliminator and cleaned by a cleaner. Further, the paper onto which the toner image has been transferred is sent to a fixing device (not shown), where fixing is completed, and then the paper is discharged to a stacker (not shown).

[0007]

As described above, the registration roller 1 provided in the middle of the paper transport mechanism from the paper feed section 4 to the photosensitive drum 3 plays the role of aligning the leading edges of the paper. However, since the feed belt 8 and reverse roller 9 are made of rubber, when the paper is conveyed by the paper feeding means 6, rubber scum is generated due to friction with the paper. When the paper is conveyed with this rubber scum attached to the paper, the rubber scum is deposited on the surface of the registration roller 1. When this accumulated rubber scum re-adheres to the surface of the paper, missing prints and transfer omissions occur, resulting in a decrease in print quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide a structure of a registration roller that prevents rubber scum and the like from adhering to the surface of the registration roller and improves printing quality.

[0009]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a transport mechanism for transporting a medium,
In the registration roller having the function of aligning the leading ends of the media, the configuration (first configuration) is characterized in that the center portion of the registration roller has a smaller diameter than the other portions.

[0010] Furthermore, the registration roller has a configuration (second configuration) characterized in that at least a central portion of the registration roller is mirror-finished.

[0011]

[Operation] In the case of the first configuration, since the center portion of the registration roller has a smaller diameter than the other portions, rubber scum and the like slip through this portion. Therefore, rubber scum and the like will not adhere to the registration rollers. Also in the case of the second configuration, since at least the center portion of the registration roller has a mirror finish, rubber scum and the like will not adhere to this portion.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a first embodiment.

FIG. 1 is a perspective view of the registration roller 11 of this example, and the registration roller 11 has a central portion 12 having a smaller diameter than other portions. Therefore, even if the paper is conveyed to the registration rollers 11 with rubber scum or the like attached to it as described in connection with FIG. There will be nothing left to do. Therefore, it is possible to prevent the accumulated rubber scum from re-adhering to the paper surface, which has been a problem in the past, and it is possible to improve printing quality by eliminating missing prints and transfer omissions. Note that the amount of rubber scum that slips through the central portion 12 is small, so it does not pose a problem.

FIG. 2 shows a second embodiment.

FIG. 2 is a perspective view of the registration roller 21 of this example, and the registration roller 21 has at least a central portion 22.
Has a mirror finish. In this figure, only the central portion is shown with a mirror finish, but the entire length may be mirror finished. In this example as well, the rubber scum on the paper that has reached the registration roller 21 passes through the central portion 22, which is a mirror-finished portion with little friction, and
It is not deposited on the surface of the registration roller 21, and the same effect as the previous example can be obtained.

[0017]

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent rubber scum etc. from accumulating and adhering to the surface of the registration roller, thereby eliminating missing prints and transfer omissions and improving print quality. It becomes possible to improve.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a registration roller according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a registration roller according to a second embodiment of the present invention.

FIG. 3 is a side view showing an outline of a conventional image recording device.

[Explanation of symbols]

11, 21 Registration roller 12, 22 Central part

Claims (2)

[Claims] Claim 1: Used in a conveyance mechanism that conveys a medium,
A registration roller (with a function of aligning the leading edge of the medium)
11) The registration roller structure according to item 11, wherein the center portion (12) of the registration roller (11) has a smaller diameter than the other portions. 2. Used in a conveyance mechanism that conveys a medium,
A registration roller (with a function of aligning the leading edge of the medium)
21) The structure of the registration roller according to item 21), wherein at least the central portion (22) of the registration roller (21) is mirror-finished.