JPH0466429A - Feeder - Google Patents

Abstract

PURPOSE:To increase the number of sheets processed per unit time and to certainly synchronize an optical system in the feeder of a picture forming device by making a feeding means on the upstream side temporally stop the feeding of the recording paper at the time when a carrying sensor has detected the following recording paper so long as a feeding means on the downstream side detects the recording paper. CONSTITUTION:In the case where a middle sensor S2 has detected a precedent transfer paper in continuously feeding the transfer paper from a tray 4, the rotations of feed rollers R5,R8, R9 are temporally stopped to temporally stop the tip of the second transfer paper at the position of a carrying sensor S3. When a middle sensor PS2 can not detect the rear end of the precedent transfer paper, the feed rollers R5, R8, R9 rotate again, and the carrying process of the following transfer paper is started at the same time. Thus two sheets of the transfer papers can be fed at the same time to increase the capacity of the transfer paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a feeding device for increasing the number of sheets processed in an image forming apparatus or the like.

[Prior Art] There are two types of paper feed cassettes that can be loaded in a copying machine.
If there are 3 to 3 types of paper cassettes, a mechanism is adopted in which the paper cassette is inserted from the side of the copying machine, but if the number of paper cassette types (sizes) is to be increased, it is necessary to insert the paper cassette separately from the main body of the copying machine. A paper feed unit (PFU) is installed,
It is installed at the bottom of the copying machine so that multiple paper feed cassettes can be loaded into the paper feed unit. In order to improve operability, this paper feeding unit employs a front loading mechanism that allows the paper feeding cassette to be loaded and removed from the front.

[Problems to be Solved by the Invention] However, when the transfer paper is fed from a paper feeding unit installed separately from the main body of the copying apparatus, the paper feeding path from the paper feeding cassette to the photoreceptor drum is becomes very long.

As a result, when increasing the number of copies per unit time (CPM), the next transfer paper is fed from the paper cassette before the preceding transfer paper is actually fed into the photoreceptor drum. In such a case, two sheets of transfer paper will be present on the paper feed path.

However, due to slipping on the rollers on the paper feed path, etc.
Since the synchronous relationship between the first sheet of transfer paper and the first sheet of transfer paper is not guaranteed, there is a problem in that the exposure optical system cannot be synchronized with the second sheet of transfer paper. In addition, there were cases in which a second sheet of transfer paper was connected to the first sheet of transfer paper.

The present invention solves these drawbacks, increases the number of sheets processed per unit time, ensures synchronization with the optical system, and prevents two sheets from being fed at the same time. The purpose is to provide a transmission device.

[Means for Solving the Problems] To this end, the present invention provides a storage section that stores recording materials such as transfer paper, a first feeding means that feeds the recording materials one by one from the storage section, a first detection means for detecting recording material provided downstream of the first feeding means; a second feeding means provided downstream of the first detection means; and a second detection means provided downstream of the second feeding means. and a second detection means for detecting a recording material provided, and when the first recording material is detected by the second detection means, the subsequent recording material is detected by the first detection means. In the case, the above first
The feeding operation of the feeding means is stopped, and when the previous recording material is no longer detected by the second detection means, the feeding operation of the first feeding means is restarted.

[Examples] Examples of the present invention will be described below. FIG. 1 is an explanatory diagram of a transfer paper feeding path in one embodiment, and FIGS. 2 to 4 are paper feeding timing charts.

In FIG. 1, 1 is a photosensitive drum that is exposed to light by an optical system (not shown) and toner is developed, 2 is an upper paper feed cassette loaded in the main body of copying machine A, 3 is a similar lower paper feed cassette, and 4 is a double-sided paper feed cassette. copy unit (ADU) tray,
5 is the upper paper feed cassette of the paper feed unit (PFtJ), 6
is a similar lower paper feed cassette.

In addition, R1 is a registration roller, R2 is an intermediate conveyance roller,
R3 is a vertical conveyance roller, R4 is a PFU conveyance roller, R5 is an ADU conveyance roller, R6-R11 is a feed roller, R12
~R16 is a feed roller that feeds out the transfer paper one by one from the cassette.

PS1 is an optical registration sensor that detects the transfer paper that has just arrived at the registration roller R1; PS2 is an optical intermediate sensor that detects the transfer paper that has left the intermediate conveyance roller R2;
PS3 is an optical ADU conveyance sensor that detects the transfer paper coming out of the duplex copying unit, and PS4 is an optical PFU conveyance sensor that detects the transfer paper conveyed from paper feeding unit B.

Now, in this copying apparatus, when feeding A4 size transfer paper from the lower cassette 3 of the copying apparatus main body A, the second
The paper feeding is performed at the timing shown in the figure. That is,
For example, when you press the copy button after setting three consecutive copies, the exposure light source (not shown) runs backwards from the home position (overrun position), reverses itself at the reversal point, and then reverses itself again using the center sensor. Return to the point (
Self-diagnosis is performed for the above period. ), and then exposes and scans the document at a predetermined speed.

On the other hand, when the copy button is pressed, one sheet of transfer paper is sent out from the lower cassette 3 by the feed roller R13, and the transfer paper is successively fed by the feed roller R7 and the intermediate conveyance roller R2, and then the registration sensor When the leading edge is detected by PS1, the driving of rollers R2 and R7 is stopped, and the transfer paper is temporarily stopped in a state in which it abuts against registration roller R1.

Then, at the timing when the exposure light source passes the brake sensor, the registration roller R1 starts to rotate, and the transfer paper that was in contact with it is fed in the direction of the photoreceptor drum 1, and the leading edge of the transfer paper and the leading edge of the toner image. Copying (toner image transfer) is performed at the appropriate timing. The registration roller R1 stops after rotating by an amount corresponding to the size of the transfer paper.

When the predetermined timer time T1 has elapsed from the start of rotation of the registration roller R1, only one sheet of transfer paper is sent out again from the lower cassette 3, and the same copying process as described above is performed.

In this way, when the transfer paper is fed from the lower cassette 3, the next transfer paper is fed from the cassette 3 after the previous transfer paper is sent out from the registration roller R1, as in the conventional case.

FIG. 3 is a diagram showing the timing when three sheets of transfer paper are successively fed from the tray 4 of the duplex copying unit.

When feeding transfer paper from tray 4, the copying apparatus has already started operation, so self-diagnosis is not performed. Therefore, the A4 transfer paper in tray 4 is transferred to the feed roller R14.
At the same time, the exposure light source of the optical system runs backwards from the overrun position, reverses itself at the reversal point, and stops there once it is detected by the center sensor. During this time, the transfer paper is sent by rollers R8, R9, R5, R3, and R2, and when it is detected by registration sensor PS1, rollers R2 and R
3 stops rotating, hits the registration roller R1, and stops once.

On the other hand, the exposure light source of the optical system runs backwards toward the reversal point from the time when the leading edge of the transfer paper is detected by the intermediate sensor PS2, is reversed there, and performs exposure scanning of the document at a constant speed.

Then, at the timing when the exposure light source is detected by the brake sensor, the registration roller R1 starts rotating to refeed the transfer paper, and as in the case described above, the timing between the leading edge of the toner image and the leading edge of the transfer paper is aligned. It will be done. At this time, the conveyance rollers R2 and R3 also resume rotation.

The second transfer paper is continuously sent out after the timer time T2 has elapsed since the previous transfer paper was sent out.

When this second transfer paper is detected by the ADU conveyance sensor PS3, if the first transfer paper is still detected by the intermediate sensor PS2, the paper feed rollers R5, R8,
R9 rotates or stops temporarily.

As a result, the leading edge of the second transfer paper is located at the transport sensor PS.
Pause at position 3. Further, the third sheet of transfer paper also stops at the same time.

Then, after the feeding of the first sheet of transfer paper is started by the registration roller R1, the trailing edge of the transfer paper is detected by the intermediate sensor PS2.
When it is no longer detected, rollers R5, R8, and R9 start rotating, and conveyance of the second sheet of transfer paper is resumed. At this time, the conveyance of the third sheet of transfer paper, which had also been stopped, is restarted.

After that, while the second sheet of transfer paper is being detected by the intermediate sensor PS2, the third sheet of transfer paper is being detected by the ADU conveyance roller PS3.
If detected, the conveyance of the third sheet of transfer paper is also temporarily stopped until the preceding second sheet of transfer paper is no longer detected by the intermediate sensor PS2, as described above.

FIG. 4 is a diagram showing the timing when three sheets of A3 size transfer paper are continuously fed from the lower cassette 6 of the paper feed unit B. When the copy button is pressed, one sheet of transfer paper is sent out from the cassette 6 by the delivery roller R16,
The sheet is fed by the feed roller 11, PFU conveyance roller R4, vertical conveyance roller R3, and intermediate roller R2, and when the leading edge is detected by the registration sensor PS1, the rotation of the intermediate roller R2 and vertical conveyance roller R3 is stopped, and the The transfer paper is temporarily stopped when its leading edge hits the registration roller R1.

On the other hand, the exposure light source of the optical system runs backwards from the overrun point and is reversed at the reversal point, as in the case explained in Fig. 2.
The vehicle is temporarily stopped at the position detected by the center sensor.

When the leading edge of the transfer paper is detected by the intermediate sensor PS2, the exposure light source of the optical system starts moving backwards from the center sensor position toward the reversal point, and after reversing at the reversal point, performs exposure at a constant speed. Start scanning.

After that, at the timing when the exposure light source is detected by the brake sensor, the registration roller R1 and the conveyance rollers R2 and R3 start rotating to feed the transfer paper, and as in the above case, the leading edge of the toner image and the transfer paper are separated. The timing with the tip is taken.

The second sheet of transfer paper is continuously sent out after the timer time T3 has elapsed since the previous transfer sheet was sent out.

This second sheet of transfer paper is the PFU transport sensor PS4.
When the first transfer paper is detected by the intermediate sensor PS2
If it is still detected, the transport rollers R2 to R4
, the rotation of the paper feed roller R11 stops. As a result, the second sheet of transfer paper is temporarily stopped at the position of the vertical conveyance sensor PS4.

Then, when the first sheet of transfer paper starts to be fed by registration roller R1 and is no longer detected by intermediate sensor PS2, rollers R2 to R4 and R11 start rotating, and the second sheet of transfer paper starts to be fed. Conveyance of the transfer paper is resumed.

Concerning the third sheet of transfer paper, execution/stop of conveyance is similarly controlled in relation to the position of the second sheet of transfer paper.

Flowcharts summarizing the above operations are shown in FIGS. 5 to 8. "First feeding" here means rollers R5, R8, and R when feeding from tray 4 of the duplex copying unit.
In the case of feeding from paper feeding unit B, feeding by rollers RIO or R11 and R4 is shown. "Second
"Feeding" indicates feeding by rollers R2 and R3. The "first detection means" detects the ADU conveyance sensor PS3 in the case of feeding from tray 4 of the duplex copying unit, or the paper feed unit B.
In the case of feeding from , PFU sensor PS4 is shown. "Second
"Detection means" indicates the intermediate sensor PS2.

In addition, although the embodiment applied to a copying apparatus has been described above, it goes without saying that the present invention can be similarly applied to a recording apparatus such as a laser printer that takes in a recording signal from the outside.

[Effects of the Invention] As described above, according to the present invention, even if the paper feeding path from the recording material storage section such as a paper feeding cassette to the image transfer section is long, it is possible to feed two sheets of transfer paper at the same time on the paper feeding path. This has the advantage that it is possible to feed the recording material, and also that it can be accurately synchronized with the optical system at this time, and that the two sheets of recording material do not overlap on the paper feeding path.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the paper feeding path of a copying apparatus according to an embodiment of the present invention, FIG. 2 is a timing chart of the optical system and paper feeding system when paper is fed from a cassette inside the copying apparatus main body, and FIG. 3 is a timing chart of the optical system and paper feeding system. 5 is a timing chart of the optical system and paper feeding system when paper is fed from a paper feeding unit installed at the lower side of the duplex copy inside the main body of the copying apparatus, and FIGS. 5 to 8 are flowcharts. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Upper cassette/sort of main unit, 3... Lower cassette of main unit, 4... Tray for double-sided copying, 5... Upper cassette of paper feed unit, 6...・
- Lower cassette of paper feed unit, R1 to R16--Roller, PSI to PS4-...Optical transfer paper detection sensor. Figure 1 Agent: Patent Attorney Tsuneaki Nagao Figure 6

Claims (1)

[Claims] (1) A storage section for storing recording materials such as transfer paper, a first feeding means for feeding the recording materials one by one from the storage section, and a downstream part of the first feeding means. A first detection means for detecting a recording material, a second feeding means provided downstream of the first detection means, and a second detection means for detecting a recording material provided downstream of the second feeding means. and when the first recording material is detected by the first detection means when the first recording material is detected by the second detection means, the feeding of the first feeding means is performed. The operation is stopped and the second
A feeding device characterized in that the feeding operation of the first feeding device is restarted when the previous recording material is no longer detected by the detection device.