JPH05238569A - Paper feeder - Google Patents

Abstract

PURPOSE:To prevent performance from deteriorating due to paper powder by stabilizing the feed performance, in a paper feeder for a printer of a copying machine. CONSTITUTION:By a constitution wherein speed control is performed in two steps of riseup control, to steady operation and steady rotational speed control by an exclusive use drive motor 24 which cab speed-control a pickup roller 22, its rotational speed is not increased to rise up quickly, and a peripheral speed of the pickup roller 22 agrees with a linear speed of recording paper 6, so that a slip between the pickup roller 22 and the recording paper 6 can not be generated and generation of paper powder can be reduced by stabilizing the feed performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device having means for stabilizing feeding performance.

[0002]

2. Description of the Related Art In recent years, attention has been paid to the stability of feeding performance in paper feeding devices such as copying machines and printers.

The structure of a general printer will be described with reference to FIG. The exposure device 3 irradiates the recording image with optical information, and the charging device 1 charges the recording medium 2 on which the electrostatic latent image has been formed to supply the developer to make the electrostatic latent image visible by the phenomenon device 4. Image. In order to bring the recording paper 6 into close contact with the visualized recording body 2, the recording papers 6 stacked in the paper feeding device 5 are separated and fed one by one. The visible image of the recording body 2 is transferred by the transfer device 7 to the recording paper 6 that is in close contact with it, and is fixed by the fixing device 8. In the figure, 9 is a paper ejecting device which reverses the fixed recording paper 6 and guides it toward the upper surface of the upper cover of the printer body. Touch the surface of body 2,
A cleaning device for removing the developer remaining on the surface thereof, 12 is a registration roller for temporarily holding the recording paper 6 before the recording paper 6 delivered from the paper feeding device 5 is conveyed to the recording medium 2, and 13 is the recording paper 6 Is a registration sensor for detecting that the paper has been conveyed to the registration roller 12.

The driving means of the printer configured as described above will be described with reference to FIG.

The main motor 16 is used as a driving source to drive the developing device 4, the fixing device 8, the paper discharging device 9, the drum (not shown), the cleaning device 11, and the paper feeding temporary standby device 18 through a series of gear trains 17. is doing. Further, the sheet feeding device 5 is driven by using the dedicated drive motor 19 of the pickup roller as a drive source. Then, according to a control time chart which will be described later, the pickup roller is switched on / off by the pickup roller dedicated drive motor 19, and the registration roller is switched on / off.
I'm going.

A conventional sheet feeding device will be described below.
As shown in FIG. 5, when the recording papers 6 stacked in the paper feed cassette 21 are sent from the uppermost recording paper 6 to the pickup roller 22, the separation pad 23 prevents the double feeding of the recording papers 6. There is. In the figure, 19 is a dedicated drive motor that drives only the pickup roller 22, 25 is a follower registration roller of the registration roller 12 in the paper feed temporary standby device, 14 is a recording paper guide member from the pickup roller 22 to the registration roller 12, and 15 is a recording paper guide member. Guide members 26, 27, 28 facing the recording paper guide member 14 are drive transmission gears for transmitting the drive of the dedicated DC motor 24 to the pickup roller 22.

The pickup roller 22 having the above-mentioned structure
The speed control will be described with reference to FIG.

In FIG. 5, at time A, the dedicated drive motor 19 does not rotate until a paper feed command is received from a control unit (not shown), but at time B, the dedicated drive motor 19 is in steady rotation according to the paper feed command. The control is started as described above, and the rotation becomes steady at time C. When the steady rotation ends, the rotation stops at time D. As shown in FIG. 6, the pickup roller 22
Since the number of revolutions of No. 2 rapidly increases from 0 to a predetermined number of revolutions, a slip corresponding to a shaded portion occurs until the peripheral velocity of the pickup roller 22 and the linear velocity of the recording paper 6 substantially match.

[0009]

As described above, the slip caused by the conventional structure varies depending on the conditions such as the use environment, the type of recording paper, the surface condition of the pickup roller, and the like, which makes the feeding performance unstable and causes the slip. There is a problem that misfeed occurs when it is remarkable, and that slipping causes a large amount of paper dust and adversely affects various performances (cleaning performance, developing performance, etc.) of other devices.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems, and to provide a paper feeding device having stable feeding performance and preventing performance deterioration due to paper dust.

[0011]

In order to achieve this object, the paper feeding apparatus of the present invention uses a dedicated drive motor capable of controlling the speed of the pickup roller to control the speed in two stages, that is, startup control until steady rotation and steady rotation control. It is configured to control.

[0012]

With this structure, the rotation speed of the pickup roller is not sharply raised, the peripheral speed of the pickup roller and the linear speed of the recording paper are made to coincide with each other, and slippage between the pickup roller and the recording paper does not occur.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1 showing an embodiment of the present invention, the same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

Since the structure and driving means of the conventional printer described in FIGS. 3 and 4 are the same in this embodiment, the description thereof will be omitted.

As shown in FIG. 1, the feature of this embodiment lies in that a dedicated drive motor 24 capable of speed control such as a stepping motor is used in place of the dedicated drive motor 19 in the conventional structure. It is in.

The pickup roller 22 having the above structure
Speed control will be described with reference to FIG.

In FIG. 2, at time A, the dedicated drive motor 24 does not rotate until a paper feed command is received from a control unit (not shown), but at time B, the dedicated drive motor 24 is in steady rotation in accordance with the paper feed command. As described above, the control is started with an inclination without rapidly increasing the rotation speed, and the rotation becomes a steady rotation at time E. When the steady operation ends, the rotation stops at time D. As shown in FIG. 2, since the rotation speed of the pickup roller 22 rises slowly with an inclination, the slip generated between the pickup roller 22 and the recording paper 6 is reduced,
Since the time required to convey the recording paper 6 is stable, the feeding performance can be stabilized. In addition, the misfeed that occurs when the slippage is remarkable does not occur, and the slippage is reduced so that the generation of paper dust, which was often generated in the past, is reduced and the cleaning performance and developing performance of other devices are not adversely affected. it can. Further, by using the dedicated drive motor 24 as a stepping motor, the cost can be reduced.

[0019]

As is apparent from the above description of the embodiments, the present invention has a structure in which the speed of the pickup roller is controlled in two stages, that is, the startup control until steady rotation and the steady rotation control by the dedicated drive motor. It is possible to realize an excellent paper feeding device with stable performance and preventing performance deterioration due to paper dust.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a concept of a main part of a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a time chart showing the relationship between the peripheral speed of the pickup roller and the recording paper linear speed during operation of the paper feeding device.

FIG. 3 is a schematic front view showing the concept of a printer using a sheet feeding device of a conventional example and an example of the present invention.

FIG. 4 is a schematic rear view showing the concept of driving means of the printer of FIG.

FIG. 5 is a schematic sectional view showing a concept of a main part of a conventional paper feeding device.

FIG. 6 is a time chart showing the relationship between the peripheral speed of the pickup roller and the linear speed of the recording paper during operation of the paper feeding device.

[Explanation of symbols]

 6 Recording paper 22 Pickup roller 23 Separation pad 24 Dedicated drive motor

Claims (2)

[Claims] 1. A recording paper stacking unit for stacking recording papers for printing image information, a pickup roller for feeding the stacked recording papers, and a pressing roller for pressing the recording papers with a constant pressing force. A sheet feeding device equipped with a separating member for preventing double feeding and a dedicated drive motor for controlling the speed of the pickup roller, wherein the pickup roller is speed-controlled in two stages of start-up control until steady rotation and steady rotation control. Paper feeder that is controlled. 2. The sheet feeding device according to claim 1, wherein the drive motor dedicated to the pickup roller is a stepping motor.