JPH0395043A - Paper feeding system for printer - Google Patents

Abstract

PURPOSE:To prevent the dispersion at a paper feed starting position in a paper feeding device and prevent the generation of the catching jam in a continuous printing speed up resisting part by performing reserve feeding by a simple means, provided with a paper existence detecting sensor set in the paper feeding downstream direction of a feed roller, until the position of this sensor before starting paper feeding. CONSTITUTION:Reserve feeding is performed at a paper feed roller 11 from the time of a paper existence detecting sensor 14 detecting the rear end of a preceding paper sheet fed by the feed roller 11 until the time of the paper existence detecting sensor 14 detecting the tip of a following paper sheet to be fed, thus setting the paper feed starting position. The dispersion of forward falling quantity in a paper feeding device 1 can be thereby absorbed.

Description

[Detailed Description of the Invention] (Industrial Technical Field) The present invention relates to a paper feeding system for a printer that conveys paper from multiple paper feeding devices to multiple wandering paper devices, and in particular, the present invention relates to a paper feeding system for a printer that transports paper from multiple paper feeding devices to multiple paper wandering devices, and in particular, the present invention relates to a paper feeding system for a printer that transports paper from a plurality of paper feeding devices to a plurality of wandering paper devices. This is related to the paper feeding method used.

(Prior Art) It is known that in a printer paper feeding system that transports paper from multiple paper feeding devices to multiple wandering paper devices, the printer is used by being connected to a host system such as a computer. .

In this case, a registration sensor is provided upstream of the printer's registration rollers to control the start of image writing.
Performs paper spacing control, jam detection, etc. (Problems to be Solved by the Invention) For example, system printers such as laser printer systems are required to speed up continuous printing.

In a conventional system printer of this type, as shown in FIG. 4, there is a paper feeding device L and a registration roller 2 that feeds paper 13 at a predetermined timing to an image transfer section in the printer engine.
A registration sensor 20 is set between the paper (upstream in the paper feeding direction), and this controls the paper spacing.In order to achieve high-speed continuous printing, the paper is fed so that the paper is fed at the shortest paper spacing possible. It is necessary to control the operation timing of roller 11. In the case of continuous printing, the timing to start feeding the next paper is after a certain period of time for each paper size, from the time when the previous paper is the registration roller 2 and the registration roller 2 restarts after waiting for image data, alignment, etc. It is common practice to do so.

In this case, the leading edge position of the previous paper is a registration position and is constant, but the leading edge position of the next paper is determined using the FRR method (feeding is performed using paper feeding roller l1, and double feeding is performed using reverse roller 12). Depending on the paper feeding method (which returns the paper), the leading edge of the paper may be at the normal position of the calling roller 10 as shown in Fig. 4 (1).
As shown in Fig. 4 (2), the position of the leading edge of the paper may be at the position of the paper feed roller 11, causing variations. 6 The time charts at this time are shown in Figs. 5 (1) and (2), respectively. This causes variation (a>b) between classes a and b in the sensor 20. By the way, the timing of the start of feeding the next paper (operation of the paper feeding roller) is constant, but the timing of the start of feeding of the next paper is constant, but the timing shown in Fig. 4 (1) and (
It is impossible to distinguish between the states of 2) in the control unit. Therefore, if the paper feed timing is determined so that the maximum speed is achieved when the paper starts from a fixed position as shown in Figure 4 (1), the paper will be moved forward as shown in Figure 4 (2). It is clear that when starting from this state, the leading edge of the next paper catches up with the trailing edge of the previous paper in the registration sensor 2, resulting in a jam.

In addition, if the paper feed timing is determined so that the maximum speed is achieved when the paper starts from the forward position as shown in Figure 4 (2) above, the paper will start from the normal position as shown in Figure 4 (1). In this case, the paper gap increases, causing the problem that the speed becomes slower than the actual speed that the printer can achieve.

As an extreme example, if paper is started from a position where paper l3 comes out before paper feed roller 1l as shown in FIG. 4 (3) due to double feeding, the registration sensor 20 detects the trailing edge of the front paper. It is obvious that the leading edge of the next paper will catch up and cause a jam.

This type of catch-up jam generally occurs because the linear speeds of the paper feed roller 1l and the registration rollers 2 are not equal, and the linear speed of the paper feed roller 11 is faster than the linear speed of the registration roller 2. This happens when the leading edge of the paper catches up. If there is a catch-up in this way, the paper length detection detects that the paper is longer than the specified size, resulting in a paper mismatch or other jam detection, that is, a catch-up jam.

(Objective of the Invention) The present invention solves the above-mentioned problems, keeps the paper feeding start position constant, and... The purpose of the present invention is to provide a paper feeding method that speeds up continuous printing and prevents the occurrence of catch-up jams in the registration section.

(Structure and operation) In order to achieve the above object of the present invention, the present invention includes a registration sensor set in the paper feeding upstream direction of the registration roller, and a paper presence detection sensor set in the paper feeding direction downstream of the paper feeding roller, The paper feed roller performs preliminary feeding from the time when the paper presence detection sensor detects the trailing edge of the previous paper fed by the paper feed roller until the paper presence detection sensor detects the leading edge of the next paper fed to the secondary paper. It is characterized by absorbing variations in the amount of advance in the paper feeder by feeding the paper and keeping the paper feed start position constant. In addition to the registration sensor, the present invention has a paper presence detection sensor installed on the downstream side of the paper feed roller on the paper feed device side, so that before starting paper feeding, preliminary paper feeding is performed to this sensor position. By always aligning and keeping the paper feed start position constant, the paper feed start position is prevented from becoming loose, increasing the speed of continuous printing, and preventing the occurrence of catch-up jams in the registration section.

(Embodiment) FIG. 1 is a diagram for explaining the operating state of an embodiment of the method of the present invention, and FIG. 2 shows its operating time chart.

As shown in FIG. 1, the paper feeding device 1 has a new structure in which a paper presence detection sensor 14 is newly installed in the paper feeding downstream direction of the paper feeding roller 11, and the other members are as shown in FIG. 4.

In this embodiment, in the state shown in FIG. 1(1), there is a paper feeding command from the control unit, the paper feeding roller 11 operates, and the trailing edge of the leading paper 13-1 is fed to the front paper 13-1 as shown in FIG. 1(2). After the paper presence detection sensor 14 detects the next paper 13-2, the original paper feeding command continues until the paper presence detection sensor 14 detects the leading edge of the next paper 13-2 at the position shown in FIG. 1 (3). In the previous state, a preliminary paper feeding operation is performed. That is, when the original paper feed starts, the paper presence detection sensor 1 always determines the paper leading edge position of the next paper 13-2.
At position 4, it is kept constant and can absorb variations in the amount of advance.

Figures 2 (1) and (3) show the paper presence detection sensor 1 of the present invention.
4 is installed, FIG. 2 (2) is a timing chart corresponding to the case of FIG. 4 (2), and FIG.
Figures (4) and (5) also show timing charts corresponding to the case of Figure 4 (3).

As shown in the timing charts shown in FIGS. 2 (1) and (2), in the case of paper feed control with the paper presence detection sensor 14 installed,
The variation in the paper leading edge position of the next paper 13-2 is shown in Figure 1 (2).
As shown in the figure, the rear end of the front paper 13-1 is detected by the paper presence detection sensor l.
4, and then detect the leading edge of the next paper l3-2 as shown in Figure 1 (3).
By operating the paper feed roller l1 (preliminary paper feeding operation) until the paper detection sensor 14 detects the presence of paper as shown in FIG.
At the start of the original paper feeding, the paper leading edge position of the next paper l3-2 is always aligned with the position of the paper presence detection sensor l4 and is constant, so the paper spacing at the registration sensor 20 is as shown in FIG. 2 (1). As shown in (2), c = d, and no variation occurs.

Also, Figure 4 (1). Compared to (2), in the case of Figure 1 (3), it is clear that the paper feed start position is at register sensor 2.
Since it is close to 0, the paper feeding start command can be issued earlier. In other words, compared to the time charts shown in FIGS. 5 (1) and (2), the time charts shown in FIGS. ) It is possible to shorten the time until ON (f>g), and it is possible to increase the continuous printing speed.

Next, we will discuss how to prevent catch-up jams in the resist section.

As shown in FIG. 2 (5), the registration sensor 20 causes the leading edge of the next sheet 13-2 to catch up with the trailing edge of the leading sheet 13-1.
The paper gap between the trailing edge of the first paper and the leading edge of the next paper, for example, Fig. 2 (1) ~
When the paper gaps c and d shown in (3) cannot be detected and a catch-up jam occurs, the paper presence detection sensor l4 detects the presence of paper as in this embodiment. This means that after the registration roller (2) is turned on, the paper presence detection sensor 14 will detect the rear end of the front paper 13-l (h) (Figure 2 (3), (4
)) is still detecting the presence of paper, and if this double feeding is detected, after turning on the registration roller (2), the paper feed roller (11) is turned on at time i when normal paper feeding starts. Instead, the start is delayed by a time e. As a result, the front sheet 13-1 can be advanced by the time e and released, and a jam caused by the registration sensor 20 can be prevented. Figure 3 shows the resist portion (Figure 2 (3),
A flowchart for preventing a catch-up jam in (4) (time chart) is shown below. That is, the time h during which the paper presence detection sensor 14 would detect the trailing edge of the front paper l3-1.
Based on this, it is determined whether there is paper or not (Se). Next, if there is no paper, the paper feed roller 11 is turned on if the normal paper feeding start time i has arrived (S2). In addition, if there is paper, when i + e, which is the time e of the normal paper feed start, is reached, the paper feed roller 1l is turned on and the previous paper 1 is loaded.
Proceed with step 3-1 (S3).

(Effects of the Invention) As explained above, the method of the present invention uses a simple method in which a paper presence detection sensor is set in the downstream direction of the paper feed roller, and performs preliminary paper feeding to this sensor position before starting paper feeding. ,
By eliminating variations in the paper start position rt at paper feed Ftli't, it is possible to increase the continuous printing speed and prevent the occurrence of catch-up jams in the registration section.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the operating state of an embodiment of the method of the present invention, FIG. 2 is an operation time chart of FIG. 1, FIG. 3 is a flowchart for preventing catch-up jam in the registration section, and FIG. FIG. 5 is an operation time chart of FIG. 4 for explaining the operation state of feeding paper from the paper feeding device. ... Paper feeding device, 2 ... Registration roller,
10... Calling roller, l1... Paper feeding roller, 1
2... Reverse rotation. 13...Paper, 13-1...
Front paper, 13-2... Next paper, 14... Paper presence detection sensor, 20... Registration sensor

Claims (1)

[Claims] Equipped with a registration sensor set in the paper feed upstream direction of the registration rollers and a paper presence detection sensor set in the paper feed downstream direction of the paper feed rollers, the trailing edge of the previous paper fed by the paper feed rollers is By pre-feeding paper with the paper feed roller and keeping the paper feed start position constant from the time the paper presence detection sensor detects the leading edge of the next paper to be fed until the paper presence detection sensor detects the leading edge of the next paper to be fed. A paper feeding system for a printer characterized by absorbing variations in the amount of advance in a paper device.