JPS63199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roll paper feeding device installed in an electrophotographic device such as a copying device or an electrostatic recording device, and more specifically, the present invention relates to a roll paper feeding device that can eliminate the influence on images when cutting the roll paper. The present invention relates to a roll paper feeding device equipped with such a roll paper cutting control mechanism.

In contrast to a cassette-type paper feeder that uses a single web, a roll-type paper feeder that uses a long web avoids errors such as multiple feeding or non-feeding, and it is possible to change the cutter operation timing. It is excellent in that it can record on webs of various sizes, especially on long webs required for computer terminals. However, on the other hand, there is a problem in that the temporary stoppage of paper feeding caused by the cutter operation when cutting the roll paper causes image disturbances in the transfer section, which is the effect of so-called cut-shock on the image.

For this reason, an apparatus has been proposed in which a sag of the roll paper is formed on the conveyance path and the cut shock is absorbed by this sag. However, even with this device, with the conventional cutting method in which the cut length is freely determined regardless of the paper width, the effect of the cut yoke may affect the image when the cut length is particularly short or when wide paper is used. The drawback of appearing still remains unresolved.

The purpose of the present invention is to solve the above-mentioned problems faced by roll paper feeding devices.The present invention sets a minimum cut length according to the paper width, and even if a cut signal is output within this dimension. The present invention proposes a new device that prevents the cutter from operating and prevents the cutter from affecting the image.

The details of the present invention will be explained below based on the drawings, but first, in order to understand the contents of the present invention, the above-mentioned problems and the prerequisites of the present invention that have been adopted to solve them will be explained. Here, we will provide a detailed explanation of the conventional device and the influence of paper towels, which have not been considered until now.

FIG. 1 shows an example of the above-mentioned conventional device, in which reference numeral 1 denotes roll paper, and 2 denotes a drive roller 2a.
and a first feeding roller pair consisting of a driven roller 2b,
The drive roller 2a is configured to temporarily stop the drive roller 2a during the roll paper cutting operation by a drive stop signal that is output almost simultaneously with the cut signal. 3 is a roll paper cutter consisting of a rotating blade 3a and a fixed blade 3b,
As seen in FIG. 2, the rotary blade 3a has a cutting blade on its circumference that is inclined with respect to the axial direction, and cooperates with the fixed blade 3b to cut the paper width from one side of the roll paper 1 to the other side. It has a well-known structure that takes a proportionate amount of time to cut. Reference numeral 4 denotes a second feeding roller pair consisting of a driving roller 4a and a driven roller 4b, which, together with the first feeding roller pair, controls the circumferential speed υ of the photoreceptor drum 6.
It rotates at a slightly faster peripheral speed υ ₁ . Reference numeral 5 denotes a registration roller pair consisting of a driving roller 5a and a driven roller 5b, which rotate at approximately the same speed as the circumferential speed υ of the photosensitive drum 6. Reference numeral 7 indicates a slump absorbing guide plate provided on the paper conveyance path 8 between the second feed roller pair 4 and the registration roller pair 5.

In the above-described apparatus, the roll paper 1 is unwound by the first and second feeding roller pairs 2 and 4 and fed toward the photosensitive drum 6. However, as described above, this feeding speed υ ₁ is slightly faster than the circumferential speed of the registration roller pair 5, which is set to the same speed as the circumferential speed υ of the photoreceptor drum 6. The sludge of the roll paper 1 is gradually formed on the conveyance path 8 between the sheets 5 and 5, and this accumulates in the sludge absorption guide plate 7. If the formation time is t, the amount L of sludge formed is L=(υ ₁ −υ)t.
This sagging prevents image disturbance when cutting roll paper.In other words, the time from when a cut signal is input until the end of cutting is Operating time of clutch, solenoid, etc....t ₁ The rotary blade 3a starts rotating from the position shown (the stopping position of the rotary blade where the rotary blade is stopped so that the roll paper 1 can pass between the double blades 3a and 3b), and then the fixed blade starts rotating. Time until contacting 3b and starting cutting
...t ₂ Cutting time from when cutter 3 starts cutting until it finishes ... t ₃ , that is, the rise time of the above (t ₁ +
t ₂ ) and the cutting time t ₃ (t ₁ + t ₂ + t ₃ )
During this period, the rotation of the first feeding roller pair 2 is stopped, but
Since the photosensitive drum 6 continues to rotate at a constant speed υ during this time, the above-mentioned sag is intended to absorb the length corresponding to (t ₁ +t ₂ +t ₃ )υ. Therefore, in order to obtain a length of (t ₁ + t ₂ + t ₃ )υ or more by using a roll paper feeding speed υ ₁ faster than the circumferential speed υ of the photosensitive drum 6, (υ ₁ −υ ) t≧(t ₁ +t ₂ +t ₃ )υ... The following condition is required. In other words, in order to prevent the influence of the cutter from affecting the image, the minimum required time t min for sagging formation after the leading edge of the roll paper 1 reaches the pair of registration rollers 5 is calculated as follows: t min = υ / υ ₁ - υ ( t ₁ + t ₂ + t ₃ )... must be.

Since the paper cut length 1 is l = υ ₁ t + l ₀ , the cut length l when the sag formation time is t min is the minimum paper cut length l min, and l min = υ ₁ υ (t ₁ + t ₂ + t ₃ )/υ ₁ −υ+l ₀ . Note that l ₀ is a constant indicating the length from the cutter 3 to the registration roller 5.

Furthermore, the time required for cutting the roll paper described above also depends on the width of the roll paper 1 and the setting method. In other words, in the method using the cutting start line as the reference as shown in Figure 3A, t ₁ and t ₂ are constant, but the cutting time t ₃ from when the cutter 3 starts cutting until it finishes cutting depends on the width of the paper. The larger it becomes. Also, the third
Figure B is a center reference method that aligns the center of the roll paper 1 with the center of the device (cutter), and has excellent paper conveyance, especially when there is a large difference in paper width between narrow width paper and wide width paper. Although this method is optimal, the cutting time required for this method is related to t ₂ and t ₃ , so that [t ₂ + t ₃ ] wide width > [t ₂ + t ₃ ] narrow width.

In the roll paper setting method using the cutting end line as a reference shown in FIG. 3C, (t ₁ +t ₂ +t ₃ ) is constant regardless of the paper width.

In this way, according to the general roll paper setting method shown in Figure 3 A and B, the required cutting time (t ₁ + t ₂ + t ₃ ) is (t ₁ + t ₂ + t ₃ ) width > (t ₁ + t ₂ + t ₃ ) narrow width, and the minimum required time for forming a sag t min is (t min) wide width > (t min) narrow width.

In addition, the minimum required time for forming this sag t min
In particular, the first and second feeding rollers 2 and 4
Since it means the time required to form the minimum necessary feeding length l min of the roll paper 1 fed by , there is a relationship of l min width > l min narrow width.

FIG. 4 is a circuit block diagram constituting an embodiment of the present invention, which will be explained next based on the points mentioned above.

When a document detector (not shown) detects the insertion of a document, the first and second feed rollers 2 and 4 (FIG. 1) are driven after a predetermined timing to start a paper feeding operation. On the other hand, the paper width of the roll paper 1 is detected by a paper width detector indicated by the reference numeral 9 in FIG. Select the gate with the number of counts according to. The counter circuit receives as a count input the output from a pulse generation circuit that generates pulses using an encoder that rotates in accordance with the rotation of the paper feed roller 2 or 4, starts counting in response to the paper feed start signal, and starts counting in response to the paper width signal described above. Outputs when the selected pulse count is reached. The latch circuit performs a latching operation upon receiving the output, ANDs this with the document trailing edge signal from the document detection circuit, and inputs the output to the cutter drive circuit. If the document trailing edge signal comes before the paper feed amount reaches the minimum cut length determined by the paper width,
No output is generated until the minimum cut length is reached.
Further, if the trailing edge signal of the document comes after the minimum cutting length, an output is generated at that point, and the cutter 3 is actuated by driving a solenoid, a magnetic clutch, etc. via the cutter drive circuit. At the same time, a feed roller stop signal is input to the feed roller drive circuit, and the first
Stop the drive roller 2a.

Note that the counter circuit can be replaced with a timer circuit if the repeatability is not too high.A group of timers is provided that operates only for the minimum necessary time for sagging (t min) determined for each paper width from the start of paper feeding. It can also be configured to disable the cutting operation during operation.

The above is an example of a synchronized cut method that detects the document length and automatically cuts the roll paper to that length. It can also be applied to devices where the cut length is specified analogously using a dial.

In addition, by appropriately selecting the ratio of the feeding speed υ ₁ of the first and second feeding rollers 2 and 4 and the feeding speed υ of the registration roller 5 according to the size of the paper width, the minimum standard based on the paper width can be achieved. Minimum cut length l min equal to the length of the size, for example 420 mm for a paper width of 594 mm
(A2), 210 mm (A4) for a paper width of 297 mm By setting the minimum required time t min for the amount of sag formation, the minimum cut size of the roll paper 1 can be made as per the standard.

As described above, according to the present invention, in order to absorb cut shocks, a paper width detecting means and a sag forming amount are added to the feeding device which is provided with a means for forming sag on the roll paper conveyance path. Since a minimum cut length storage means for each paper width determined from is provided, and these outputs are used to prevent the roll paper cutting means from cutting less than the minimum cut length,
No matter what width the roll paper is cut, it is possible to avoid any adverse effect on the image.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional roll paper feeding device to which the present invention is applied, and FIG. 2 is a side view of a rotary cutter.
3A, 3B, and 3C are explanatory diagrams showing the roll paper setting method, cutting start position, and cutting end position, and FIG. 4 is a circuit block diagram showing an embodiment of the present invention. 1... Roll paper, 2... First feeding roller pair, 3
...Cutter, 4...Second feeding roller pair, 5...
Registration roller pair, 6... Photosensitive drum, 9...
Paper width detector.

Claims (1)

[Claims] 1. A feeding device that feeds a roll paper toward the electrostatic image carrier, a roll paper cutting device disposed between the feeding device and the electrostatic image carrier, and a paper roll cutting device that feeds the roll paper toward the electrostatic image carrier. In a roll paper feeding device having a sag forming means for forming sag in the roll paper on a roll paper conveyance path to the body, a paper width detection means for detecting the paper width of the roll paper, a roll paper cutting time and the above sag formation amount. a minimum cut length storage means for storing the minimum cut length determined by the above, and a cut control means for preventing the operation of the roll paper cutting means when the length is less than the minimum cut length set by the storage means and the paper width detection means. A roll paper feeding device for an electrophotographic apparatus, comprising: