JPH08319037A - Sheet material feeder and image forming device - Google Patents

Abstract

PURPOSE: To surely separate one by one a loaded sheet material and perform a high speed paper feed. CONSTITUTION: A sheet material 30 loaded on a paper feed cassette 15 is fed by a pick up roller 300. Next by paired separating paper feed rollers constituted by a paper feed roller 100 and by a separating roller 200 left hand rotated together (that is, moved in a reverse direction in a contact surface with each other), the sheet material 30 is separated sheet by sheet and fed into a conveying route. To this process, a paper feed is performed at a low speed, and after a preset prescribed time, a paper feed speed is switched to a high speed. In this way, a paper feed is surely started at a low speed, to surely separate the sheet material sheet by sheet, thereafter by feeding paper at a high speed, a high speed paper feed can be performed while maintaining conventional separating paper feed accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material feeding device such as a copying machine for conveying a sheet material to form an image and an image forming apparatus.

[0002]

2. Description of the Related Art FIG. 6 shows a sheet feeding structure in a conventional image forming apparatus.

In FIG. 6, reference numeral 30 denotes a loaded transfer member,
Reference numeral 15 is a paper feed unit for accommodating the stacked transfer members 30, 90 is a bottom plate of stacked transfer sheet materials, 70 is a rotating body for pushing the bottom plate 90 upward, 80 is a motor for driving the rotating body, and a feeding unit. A pair of separation paper feed rollers of the paper roller 100 and the separation roller 200 is provided to separate and convey only one sheet of paper, 100 is a paper feed roller for rotating in the forward direction to convey the paper, and 200 is a plurality of paper feed rollers. A separating roller that rotates in the opposite direction to separate only the uppermost part when the rollers of one sheet are sent to the roller pair and push back the second and subsequent sheets, 300 is a pickup roller for feeding the paper to the roller pair.

As the first separating means, the pickup roller 300 picks up the uppermost one sheet of the stacking transfer member and sends it to the separation sheet feeding roller pair of the sheet feeding roller 100 and the separation roller 200. This pair of separation paper feed rollers serves as a second separation means and serves as the pickup roller 30.
When two or more sheets are conveyed to the pair of separating and feeding rollers at the time of separation by 0, the upper member is advanced by the feeding roller 100, and the lower member is pushed back by the separating roller 200.

In order to realize high-speed paper feeding in such a structure, conventionally, the image forming area and the paper feeding section are driven by different motors, and the image forming area is driven at high speed in the paper feeding section.

Further, the speed is switched between the sheet feeding section and the image forming area by one motor, and the image forming area is driven at a high speed in the sheet feeding section.

[0007]

In the above-described conventional paper feeding device, the pair of separating paper feeding rollers 100 and 200 are rotating in the direction in which they are in friction with each other, and the increase in speed leads to deterioration in durability. Also, when feeding multiple sheets, the drive of each roller is controlled by a clutch so that the front sheet material does not catch up with the back sheet material so that there is a certain distance between sheets. The drive is repeatedly turned on and off via the above-mentioned means, and when the speed is increased, the precision of parts of the drive transmission means such as the clutch is required. Therefore, the cost has been increased due to the improvement in accuracy of parts.

[0008]

According to the present invention, a storage means for stacking and storing sheet materials, and a separation paper feeding means for separating and feeding the sheet materials one by one from the uppermost portion of the storage means. A sheet material detecting means provided downstream of the paper feeding and conveying path of the separating and feeding means, a drive transmitting means for driving the separating and feeding means, a driving means for driving the drive transmitting means, and the driving means. The speed switching means of the means and the speed detecting means of the driving means are provided, and the driving means is operated after the speed detecting means detects a predetermined speed signal.

The driving means is operated after the speed switching means is switched to a predetermined speed side.

Further, the speed switching means is operated after the detection signal of the sheet material detecting means is detected.

According to the present invention, the sheet feeding drive is always performed at the low speed side, and high speed sheet feeding is possible while maintaining the conventional separation sheet feeding accuracy.

[0012]

【Example】

<First Embodiment> FIGS. 1 and 2 show an image forming apparatus using a first embodiment of the present invention.

FIG. 1 shows a sheet feeding path. The sheet material 30 is stacked on the paper feed cassette 15. A pickup roller 300 sends out the stacked sheet materials. Paper feed roller 100 and separation roller 2
The sheet is separated into a single sheet by a pair of separating and feeding rollers composed of No. 00 and is sent to the transport path.

The carrying roller 114 carries the resist to the registration roller 113. The registration roller 113 operates when other conditions such as an optical system are satisfied. Photoconductor 1
The image formed by the latent image 01 is transferred to the sheet material by the transfer unit 105, separated by the separating unit 106 so as not to wind around the photoconductor, and sent to the conveyor belt 102. Fixing roller 1
03 and the pressure roller 104, and is fixed by both rollers. As it is, it is ejected outside the machine by the ejection rollers 112 and 113.

A sensor for determining a jam is arranged in each part, and 135 and 136 are conveyance sensors and 1
37 is a registration sensor, and 138 and 139 are paper discharge sensors.

FIG. 2 shows a drive configuration of each roller. Reference numeral 500 denotes a motor having speed control means of high speed and low speed, 510 is a drive belt, 520a, b and c are gears, and 530 is drive transmission. It is a clutch that is a means.

FIG. 3 is a flow chart showing the operation of this embodiment.

At 1010, an operation start command signal (not shown) is input by a copy key or the like to start the operation. 1
At 020, the speed is detected by the speed detecting means of the motor, and if the speed is low, the clutch at 530 is operated to start the paper feeding operation. After a predetermined time set in advance at 1030,
The sheet material is conveyed by switching to the high-speed operation of 1040. At 1050, it is determined whether the set number of copies have been completed. If not, the process waits at 1020 until the motor speed becomes low again. The speed is determined by the speed detecting means of the motor, and if the speed is low, the clutch 530 is operated to start the next sheet material feeding operation.

<Embodiment 2> FIG. 4 is a flow chart showing the operation of the second embodiment of the present invention, and the configuration is the same as that of FIGS. 1 and 2 in the first embodiment.

At 1010, although not shown, an operation start command signal is input by a copy key or the like to start the operation.
At 1120, the motor speed switching signal is set to low speed.
After that, the clutch of 530 is operated to start the paper feeding operation.
After elapse of a predetermined time set in 1130, 1140
Switch to the high-speed operation, and carry the sheet material. 115
At 0, it is judged whether or not the copy of the set number of sheets has been completed, and if not completed, at 1120, it waits again until the motor speed switching signal is switched to the low speed. The speed is determined by the speed detecting means of the motor. If the speed is low, the clutch 530 is operated to start the next sheet material feeding operation.

<Embodiment 3> FIG. 5 is a flow chart showing the operation of the third embodiment of the present invention, and the configuration is the same as that of FIGS. 1 and 2 in the first embodiment.

At 1010, an operation start command signal is input by a copy key or the like (not shown) to start the operation.
At 1210, the motor speed switching signal is set to low speed.
Thereafter, at 1220, the clutch of 530 is operated to start the paper feeding operation. At 1230, the sheet feeding operation is continued at a low speed until the sensor 135 detects the sheet material, and when the sheet material is detected, the operation is switched to the high speed operation at 1240. 12
At 50, determine whether the set number of copies have been completed,
If not completed, the process waits until the sheet feeding start conditions are met again at 1260. When the sheet feeding start conditions are satisfied, the process proceeds to 1210 and the sheet feeding operation is started again.

[0023]

As described above, according to the present invention, storage means for stacking and storing sheet materials, and separating and feeding means for separating and feeding the sheet materials one by one from the uppermost part of the storage means. A sheet material detecting means provided downstream of the sheet feeding and conveying path of the separating and feeding means; a drive transmitting means for driving the separating and feeding means; a driving means for driving the drive transmitting means; A speed switching means of the means and a speed detecting means of the driving means, and after the speed detecting means detects a predetermined speed signal,
The driving means is operated.

Further, the drive means is operated after the speed switching means is switched to a predetermined speed side.

Further, the speed switching means is operated after detecting the detection signal of the sheet material detecting means.

According to the present invention, the sheet feeding drive is always performed on the low speed side, and high speed sheet feeding is possible while maintaining the conventional separation sheet feeding accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming apparatus according to the present invention.

FIG. 2 is a configuration diagram of driving means of the image forming apparatus according to the present invention.

FIG. 3 is a flowchart showing a paper feeding operation in the first embodiment of the present invention.

FIG. 4 is a flowchart showing a paper feeding operation in the second embodiment of the present invention.

FIG. 5 is a flowchart showing a paper feeding operation in the third embodiment of the present invention.

FIG. 6 is a sectional view of a sheet feeding unit of a conventional image forming apparatus.

[Explanation of symbols]

 15 ... Paper feeding cassette 30 ... Sheet material 135 ... Conveyance sensor 100 ... Paper feeding roller 200 ... Separation roller 300 ... Pickup roller 500 ... Motor 530 ... Clutch

Claims (4)

[Claims] 1. Storage means for stacking and storing sheet materials, and sheet materials stacked and stored in the storage means from the top of the storage means.
Separation sheet feeding means for separating and feeding sheets one by one, sheet material detection means provided downstream of the separation sheet feeding means in the sheet feeding and conveying direction, drive transmission means for driving the separation sheet feeding means, In a sheet material feeding device having a drive means for driving a drive transmission means, a speed switching means of the drive means, and a speed detection means of the drive means, the drive is performed after the speed detection means detects a predetermined speed signal. A sheet material feeding device, characterized in that a transmission means is operated. 2. The sheet material feeding device according to claim 1, wherein the drive transmission means is operated after the speed switching means is switched to a predetermined speed side. 3. The sheet material feeding device according to claim 1, wherein the speed switching means is operated after detecting a detection signal of the sheet material detecting means. 4. A sheet material feeding device according to claim 1, and an image forming means for forming an image on the sheet material fed from the sheet material feeding device. Image forming apparatus.