JPS6366050A - Sheet skew feed detecting device - Google Patents

Abstract

PURPOSE:To judge the skew feed with a simple structure by providing two or more sheet detecting means on a straight line having a fixed angle against a straight line perpendicular to the transfer direction and judging the skew feed of a sheet based on the input sequence of detected signals. CONSTITUTION:Two reflection type photosensors 2a, 2b are arranged at predetermined positions on the sheet transfer path 5 transferring a recording sheet 1 in the arrow direction. That is, the sensor 2b is arranged on a straight line (1)1 crossing at the installation position of the photosensor 2a with a straight line (1)0 at an angle theta1. At the time of sheet transfer, if the photosensor 2a first detects the sheet 1 then the photosensor 2b detects the sheet 1, normal sheet transfer is judged. On the other hand, if the sheet 1 is detected in the reverse sequence, skew transfer is judged.

Description

[Detailed description of the invention]

L2 Bon 1 Mitsuruaki Ki is used in image forming devices such as copying machines, printers, facsimile machines, computers, etc.: 1J-3L for detecting skew feeding when conveying sheets. This is related to the A position.

[The writing iron assembly in an image forming apparatus is generally conveyed from a stacked paper feed tray to a 1" paper tray via an image transfer section. In addition, in a copying machine equipped with an automatic document feeder, the document is transported to a predetermined mounting table, subjected to exposure 19 fJt, and then transported to a predetermined tray T? i will be listed. In this way, recording sets and manuscript paper sheets are conveyed and processed, but since the paper quality of the sheets varies, there is a certain probability that skew feeding will occur during conveyance. The reality is that there is no such thing. Diagonal feeding of sheets causes problems such as paper jams, misalignment of printers 1 and 1, and image defects.Preventing these problems is essential for improving reliability, and detection of diagonal feeding is unnecessary. It belongs to the priest. Therefore, as a conventional device for detecting diagonal feed of the sea I, special 'jn If! As described in Publication No. 75G-88041, a sheet detection sensor is arranged 2pJA on a straight line perpendicular to the conveyance direction of the conveyed sheet, and the diagonal feeding is performed based on the time difference in the detection time of the conveyed sheet. It was determined whether or not this was occurring. 1■J】Self L1ζ1Tachi plate Yufuchi In this way, in the conventional diagonal feed detection device, since the 1.1 difference between the detection n of both sensors is used as the basis for discrimination, the pulse generation circuit and the・Circuit etc. are required, complicated and expensive, so why not put it on the 4th floor? There wasn't. The present invention has been made in view of the above, and an object of the present invention is to provide an inexpensive sheet diagonal feed detection device that can detect diagonal feed in a curved configuration. 1. rJA "11 Rutada no - and" The present invention is a sheet conveying device that conveys sheets, and includes two or more sheet detecting means arranged on a straight line having a constant angle with respect to a straight line perpendicular to the conveying direction. This is a sheet skew feeding detection device comprising: and a determining means for inputting detection signals from the r sheet detection stage and determining skew feeding of a sheet based on the input order of the signals. When a sheet is being conveyed normally, the sheet detecting means on the near side in the conveying direction should always operate first, so if the circular sheet detecting means operates after the other sheet detecting means. If so, it can be determined that the sheet is not being fed diagonally. Since it is necessary to detect only the sequence of operations of the sheet detecting means, a pulse generating circuit, a run circuit, etc. are not required, and the configuration is simplified, and loss can be reduced. In addition, in a sheet conveying device that conveys sheets, two
By providing two or more sheet detecting means arranged on one of the straight lines of the book and at least one or more sheet detecting means arranged on the other straight line, either the right side or the left side of the sheet It is also possible to detect diagonal feed that is preceded by . One embodiment of the present invention illustrated in FIGS. 1 to 3 will be described below. The tree break is related to the conveyance of the recording paper 1, and as shown in FIG. /I to J-, recording paper 1 moves in the direction of the arrow! 2 will be sent. The present embodiment is an example of a 18-fold J: flat conveying device in which the right side of the sheet always takes the lead when the conveyed recording sheet 1 is obliquely fed. At a predetermined position near the upper part of the sheet conveyance path 5, there are two anti-QL type light beams 20, 2b (having a light emitting element and a light receiving element).
The sheet transport path 5 that guides the paper has a surface treated with a non-reflective coating such as black. The recording paper 1 is connected to the sheet W1 feeding path 5 and the light beam Fj')a. When the recording paper 1 intercepts the light DI emitted from the light emitting element of the photosensor, the reflected light enters the light receiving element and detects the presence of the recording paper 1. be able to. The detection signals from the optical lensers 2a and 2b are input to the discrimination circuit 7 via lead wires. Here, the arrangement of optical recorders 1 and 2a and 2b and the recording paper 1
The relationship will be explained using the m2 diagram. The conveyance direction of the recording paper 1 is assumed to be upward on the paper surface as shown by the arrow. The light sensor is located at the position where the left side of recording paper 1 passes through.
28, and a straight line J passing through the same position Pa and perpendicular to the transport direction
For o, let jl be a straight line that passes through point Pa and has an angle θ1 of 41 dimensions. The straight line j1 is located at a position obtained by rotating the straight line 11o by θ1 degree counterclockwise around the point Po in FIG. Light Hint 1: On the right side of J-28, light guide 1 on the straight A1 soil.
)-2b is placed. Here, angle 01 is 1 at which diagonal feeding of recording paper 1 is allowed.
This is a large allowable value, and diagonal feeding that does not exceed this value is determined to be normal conveyance. When the recording paper 1 is fed 11i2 in a substantially normal state, the optical sensor 2a first detects the recording paper 1, and then the optical sensor 2b detects the recording M1. However, as shown in FIG. 2, when the right side of the recording paper 1 is being fed obliquely, the optical sensor is 2b. The recording sheets 1 are detected in the order of 2a. Therefore, by constructing a discrimination circuit consisting of a simple logic circuit as shown in FIG. 3, it is possible to easily discriminate diagonal feed. The signal A from the optical sensor 2a is inputted to one input terminal of the AND circuit 9 via the NOT circuit 8,
The signal B of b is inputted to one input terminal of the NO circuit 9,
The output of the AND circuit 9 is the discrimination signal S. Now, if the sheet detection level by the optical sensor is "1" and the sheet non-detection level is rOJ, then the situation (A, B) = (0°1) will occur during diagonal feeding as shown in Fig. 2. Only the discriminating signal @S becomes "1", and the other signals become rOJ. When the conveyance is carried out normally, the discrimination signal S is always rOJ, whereas in Tatsumi normal history feed 1.1, when "1" appears in S, the record is 41. It is possible to determine whether the paper 1 is being fed diagonally. This discrimination signal is output to a control circuit (not shown), and when "1" appears in the signal S, the circuit stops the operation.
Processing such as displaying an abnormality will be taken. As described above, in this embodiment, J3 has a very simple configuration of the detection device as shown in FIGS. 1 and 3, and is highly reliable and low-cost. It's coming true. In the above embodiments, skew feeding occurs when the right side of the paper always takes the lead, and when the left side takes the lead, skew feeding cannot be detected. An example in which skew feeding can be detected will be explained based on FIGS. 4 to 8. In FIG. 4, three reflective optical sensors 2a and 2b are located at predetermined positions near the upper part of the sheet conveyance path 5. 2G (having a light-emitting element and a light-receiving element) is arranged, and the sheet conveyance path 5 through which the paper is conveyed is subjected to non-reflective treatment. Detection signals 8 from the optical sensors 2a, 2b, and 2G are input to the discrimination circuit 7 via lead wires. Here, the arrangement of the optical sensors 2a, 2b, 2c and their relationship with the recording paper 1 will be explained with reference to FIGS. 5 to 7. 1 where the left side of the recording M1 passes, as in the embodiment described above.
The one located in the parking lot is the light sensor 'I, l-28, and the same location P
With respect to the straight line No that passes through o and is perpendicular to the transport direction, the straight lines that pass through point Po and form an angle θ1 are defined as J+ and J2. Direct IQ fl + is a straight line J! o in Figure 2 as point Po
It is at a position rotated by θ1 degree around 51 hours counterclockwise around , and the straight line p2 is at a position rotated 01 degrees around 51 hours. On the right side of the optical sensor 2a, on the 0 line j1 is the optical sensor 2b.
, and the optical sensor 2C is placed on the straight line 12. When the recording paper 1 is conveyed in a substantially normal state, the optical sensor detects the recording paper 1 in the order of 2c, 2a, and 2b, as shown in FIG. This means that even if the right or left side of recording paper 1 precedes, the angle made by the leading edge of recording paper 1 with respect to the direct KAjo is 01.
If it is within the range, the optical sensor detects the recording paper 1 in the order indicated by F, and it is considered normal. However, as shown in FIG. 6, when the right side of the recording paper 1 is in front and the straight line jo and the leading edge of the recording paper 1 are are 2c, 2b, 2a, etc., and are considered abnormal. Further, as shown in FIG. 7, when the left side of the recording paper 1 is in front and the straight line fJo and the leading edge of the recording paper 1 are <'K =) the angle θ3 exceeds the angle θ1, the optical sensor detects the recording paper 1. The order is 2a, 2c, 2b, etc., which is considered abnormal. That is, when the time when the optical sensor 2a detects the recording paper 1 is between the detection times of the optical sensors 2C and 2b, it is normal, and anything else other than the above is considered abnormal. Next, FIG. 8 shows a determination circuit for determining whether the conveyance of the recording paper 1 is normal or abnormal. Detection No. 15 Δ from optical sensors 2a, 2b, and 2C. F3. It inputs C and outputs the discrimination signal S.
Simple i111 of lt circuit 10.12 and AND circuit 11
The signal 8A of the input 28 is connected to the NOR circuit 10 and the AND
The signal B of the optical sensor 2b is input to one input terminal of the NOR circuit 10, and the IS signal C of the optical sensor 2C is input to one input terminal of the AND circuit 11. NOR circuit 10 OJ: U AND times fi511 (7)
Output No. 0 is input to the input terminal of the NOR circuit 12, and N
The output of the OR circuit 12 becomes the discrimination signal S. The transition states of the signals Δ, B, and C when the sheet detection level is "1" and the sheet non-detection level is "0" and the sheet is conveyed in a normal state are shown below. (A, B, C) = (○, O, O) ↓ (0, 0, 1) (1, 0, 1) ↓ (1, 1, 1> Logic that the result S is rOJ in any of these states The formula is: =AjB+AjC The logic circuit that realizes this is the 1 discrimination circuit 7 shown in FIG. 8. Therefore, in this circuit, the recording paper 1 is transported as shown in FIG. In the case of IC, the state (A, B, C) = (0, 1, 1>) occurs exactly as shown in Figure 6, but at this time "1" appears in S. Also, as shown in Figure 7, When the recording paper 1 is conveyed, as shown in Fig. 7, the state (△. appears. In other words, when normal conveyance is being performed, the discrimination signal S is always rOJ, but during abnormal conveyance, S is
1" appears, and it is possible to determine whether the recording paper 1 is being fed diagonally. This discrimination signal is output to a control circuit (not shown), and when "1" appears in the signal S, the circuit stops the C movement,
Processing such as displaying an abnormality will be taken. As described above, in this embodiment, the structure of the J: sea urchin detection neck shown in FIGS. 4 and 8 is very simple.
High reliability and low cost. The discriminating circuit 71 shown in FIG. 8 in the same embodiment, that is, the above-mentioned S-? This is by day of Tllll shown in Figure 9. Optical sensor 28 signal △

[YOR circuit 13 and HAN
The signal B from the optical sensor 2b is input to one input terminal of the D circuit 14, the signal C from the optical sensor 2G is input to one input terminal of the NAN II circuit 14*:)
; input to the child. The output signals of the OR circuit 13 and the HAND circuit 14 are
Input to the quiet circuit 15, output signal of the AND circuit 15]
is discrimination 1. It is No. ζ S. This circuit can also achieve the same results as in the first embodiment. In the above embodiment, two optical sensors were arranged on the -il'i line, but they could also be arranged in multiple cages at a predetermined distance apart, as shown in FIG. often,
By arranging them in this way, even if one noise on the recording paper 1 is different, it is possible to make the amount of noise the same from both the detection of the oblique feed and the detection of the paper size. That is, in the same figure, when a small paper 121 of 1 size is conveyed, the optical sensors 2a and 2b are detected. 2C is used to determine whether or not diagonal feeding is being performed, and the paper size is determined based on whether the other optical sensors 2d, 2e, 2f, and 2G are in operation. When the paper 1b is conveyed, the paper 1b is conveyed.
, 2d, and 2e are used to determine whether or not diagonal feeding is being performed.
Since the optical sensors 26 and 2e operate and the optical sensors 2f and 20 do not operate, it is determined that the paper layer has increased. Similarly, when paper 1C is conveyed, optical sensor 2a
, 2f, and 2G are used to determine whether or not diagonal feeding is being performed, and the paper size is determined based on the operation of the optical sensors 2f and 2G. Also, as shown in FIG. 11, there are three optical sensors 2a. 2b and 2G, the optical sensor 2a is fixed, the optical sensor 2b is on the straight line Jl+, and the optical sensor 2c is on the straight line J!
2 and may be moved to an appropriate position depending on the paper size. In this case, the discrimination circuit shown in FIG. 8 or 9 can be used. In the embodiments described above, the oblique feeding of the sheet is detected at the leading edge of the sheet, but it is also possible to detect the oblique feeding based on the operating order of the optical sensor at the trailing edge. In addition, although a non-contact type optical sensor was used as the sheet detection means, a hole was provided at a predetermined position on the conveyance path as a transmission type optical sensor.
It is also possible to detect the passage of the sheet by placing a light emitting element, a light receiving element, and a light receiving element above and below the hole. Furthermore, it is also possible to use mechanical switches (not only optical sensors but also magnetic sensors). 1 Dish ff1LI The present invention is capable of easily detecting skew feeding of a sheet with a simple discrimination circuit by arranging a sheet detecting means at a predetermined position, thereby improving reliability and reducing costs. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part of an embodiment according to the present invention, FIG. 2 is a diagram showing the arrangement of the optical fin 1 and the relationship between the optical fin 1 and the recording paper of the embodiment, and FIG. FIG. 4 is a perspective view of a main part of another embodiment according to the present invention, FIG.
6 and 7 are diagrams showing the positional relationship between the arrangement of the optical sensor and the recording paper in the same embodiment, FIG. 0 shows a discrimination circuit in the same embodiment, FIG. 1 and FIG. 9 show another discrimination circuit. FIG. 10 is a diagram showing the arrangement of the optical sensor and its positional relationship with paper in another embodiment, and FIG. 11 is a diagram showing the arrangement of the optical sensor and its positional relationship with paper, etc. in yet another embodiment FIG. 1... Recording paper, 2a, 2b, '2c, 2d, 2e. 2f, 2Q... Optical sensor, 3... Sheet feed roller, 4... Sheet feed [■-RA, 5... Sheet W!
Feed path, 7...Discrimination circuit, 8...N07 circuit, 9...
・To NO circuit, 10...N011 circuit, 11...
to ND circuit, 12... N011 circuit, 13...O
R circuit, 14...HAND circuit, 14...AND circuit.

Claims (2)

[Claims] (1) In a sheet conveyance device that conveys sheets, two or more sheet detection means are arranged on a straight line having a certain angle with respect to a straight line perpendicular to the conveyance direction, and detection signals from the sheet detection means are provided. 1. A sheet skew feeding detection device comprising: a determining means for inputting a signal and determining skew feeding of a sheet based on the input order of the signals. (2) In a sheet conveying device that conveys a sheet, two or more sheet detection means arranged on one of two straight lines that have a constant angle in both front and rear directions with respect to a straight line perpendicular to the conveying direction; At least one sheet detecting means arranged on the other straight line; and a determining means inputting detection signals from the sheet detecting means and determining skew feeding of the sheet based on the input order of the signals. A sheet skew feed detection device characterized by: