JPS5831841A - Curl detector of transfer sheet - Google Patents

Abstract

PURPOSE:To detect a curl of a sheet with simple constitution, by placing a point end of the sheet in a non-supported state in a stepped space, providing the stepped space on the way of a sheet conveying passage for an electrophotography copying machine and the like and providing an end position detector sensor of the sheet in said stepped space. CONSTITUTION:A step difference 20 is provided in front of a pair of conveyer rollers 19 to form a curl detecting space part 22 and arrange an ultrasonic sensor 23. In this constitution, transfer paper 18 is conveyed by the pair of conveying rollers 19, during the time its point end 21 reaches the step difference 20 to pass the curl detecting space part 22, the point end is in a non-supported condition. Here the paper end 21 is provided with conditions a-c in accordance with existence of a curl and its direction, and existence of the curl in the transfer paper 18 and a direction of the curl can be detected at a time from a time difference of transmitted and received ultrasonic waves when the paper passes on the ultrasonic sensor 23. In this way, the curl can be easily detected to prevent interference to peripheral equipments.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curl detection device for a transfer sheet in a copying machine such as an electrophotographic copying machine. FIG. 1 is a schematic configuration diagram of an electronic photocopying machine.

In this figure, a contact glass 3 on which an original 2 is placed is provided above the nursing 1.

Reference numeral 4 denotes an optical system that guides a light image to the photoreceptor 5. Photoreceptor 5
As is well known, a charging unit 16, a developing device 7, a transfer charger 8, a separation charger 9, a +)-Jung device 10, and a static elimination charger 11 are arranged in the space. 12 is a conveyance system for the transfer paper 18 in the tray 13 and cassette 14; 15 is an electrodeposition device; 16 is a paper discharge tray; and 17 is a conveyance belt. If the transferred transfer paper 18 is curled in the same direction as the photoconductor 50, it will separate from the photoconductor 5 after transfer and will be conveyed to the cleaning device 10 side while being wrapped, and if the paper jams, the cleaning device 10 This may result in damage to the product. Further, if the intermediate layer transfer paper 18 curls due to heating, paper jams may occur in the middle of the paper ejection path, or paper jams may occur within the peripheral equipment when a peripheral equipment such as a sorter is used.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transfer sheet curl detection device that eliminates the above-mentioned troubles.

That is, the curl detection device according to the present invention can detect plain paper, O
For example, a step-like curl detection space is formed in which the leading edge of the transfer sheet is unsupported during the conveyance path of a transfer sheet □ such as HP paper, No. S original drawing paper, etc. The present invention is characterized in that a position sensor consisting of, for example, an ultrasonic sensor or a plurality of microswitches for detecting the position of the leading end of the transfer sheet in an unsupported state is provided near the curl detection space.

Next, each embodiment of the present invention will be described with reference to the drawings.

FIG. 98 is a diagram for explaining the first embodiment.

The transfer paper 18 is conveyed in a predetermined direction by the rotation of the conveyor p-ra pair 19.19, and from this conveyor p-ra 19, a step 20 is provided which is one step lower in the @ direction. A curl detection space 22 is formed in which the leading end 21 of the transfer paper 18 is unsupported. Further, an ultrasonic sensor 23 is arranged in front of the conveyance roller 19 L8 toward the curl detection space 22.

Normal transfer sheet) (Shanyo paper, OHP paper * fli s
When performing curl detection on an original drawing paper, it is appropriate for the distance L1 to be about 1-16 cm+, and for the distance 11LI to be about 1 to loa+t.

While the leading edge 21 of the transfer paper 18, which has been conveyed while being held between the pair of conveyance rollers 19. 19, and the distal end portion 21G'li is in an unsupported state. At this time, if the transfer paper 18 has already curled downward, the leading edge 21 will be in the state shown in ■, and if the transfer paper 18 is not curled, it will be in the state shown in ■, and then the transfer paper 1
If the tip 8 is curled toward a hill, the tip 21 will be in a state like a ■ and will pass over the ultrasonic sensor 23, respectively.

The ultrasonic sensor 23 uses a drive circuit to emit ultrasonic waves from a transducer on the transmitting side, reflect them from an object to be detected, and receive the reflected waves at a transducer on the receiving side. It is a mechanism that detects the distance from the center to the object by amplifying it with a sense circuit and measuring the time difference between transmission and reception. Therefore, as described above, when the leading edge 21 of the transfer paper 18 is in any of the states of ■, ■, and ■, the ultrasonic sensor 23. By passing over the transfer paper 18
The presence or absence of curl, the direction of curl, and the degree of curl can be detected all at once.

Note that the mounting position of the ultrasonic sensor 23, that is, the step 20
The distance (L, -L,) from to the ultrasonic sensor 23 is such that the leading edge 21 of the transfer paper 18 does not bend due to its own weight, and the curl state of the transfer paper 18 is sufficient in the curl detection space 22. It is desirable that the distance be -.

FIG. 3 is a diagram for explaining the @S embodiment of the present invention. In this embodiment, the fixing heating roller pair 24t2
A lower step 20 is provided in front of 4, a curl detection space 22 is formed by this step 20, and an ultrasonic sensor 23 is disposed facing the curl detection space s22. The method for detecting curls in the transfer paper 18 is the same as that in the first embodiment, so its explanation will be omitted.

FIG. 4 is a diagram for explaining a 1g embodiment of the present invention. In this embodiment, a lower step 20 is provided in front of 25.25 pairs of conveyor belts (25.25) for conveying the transfer paper 18, and a curl detection space 22 is formed by the step 20. In this curl detection space section 22,
Three microswitches, that is, a lower microswitch 26a, a middle microswitch 26b, and an upper microswitch 26C, are arranged in a vertical relationship.

Therefore, when the transfer paper 18 is curled downward, its tip 21 is the detection end of the lower stage microswitch 26α, and when the transfer paper 18 is not curled, the tip 21 is the detection end of the middle stage microswitch 26b. Also transfer paper 1
8 is curled upward, the tips 21 come into contact with the detection ends of the upper microswitches 26C, and as a result, the presence or absence of curl and the curl direction are detected. It is a figure for explaining an example. In this embodiment, a curl detection device is provided at a location where the transfer paper 18 is conveyed downward. In front of the conveyance rollers 19 and 19, steps 20 are provided on the left and right sides, thereby forming a curl detection space 22,
An ultrasonic sensor 23 is installed facing the curl detection space 22. Detection of the presence or absence of curl, the direction of curl, and the degree of curl are the same as in the It embodiment described above, so a description thereof will be omitted.

If the curl detection device is installed at a location where the transfer paper 18 is conveyed downward as in this embodiment, curls can be detected without being affected by the stiffness of the transfer paper 18.

FIG. 1 is a schematic diagram of a curl correction device connected to the curl detection device of the present invention. In front of the rotation guide plate 27 which can be rotated at a predetermined angle, there is a hard metal roller 28 in the middle, and above and below there are elastic rollers 29af2 made of rubber.
9b is placed. The speed of the hard roller 28 v1.
Shoulder speed v3 of the lower elastic roller 29a. Upper elastic roller 2
The same speed V of 9b is adjustable.

For example, when the curl detection device detects that the transfer paper 18 curled downward is being conveyed, the guide plate 27 is positioned to face the joint between the lower elastic roller 2911 and the hard roller 228 based on the detection signal. , vl>v,
The hard q-ra 28 and the lower elastic roller 2 are arranged so that the relationship is as follows.
By passing the curled transfer paper 18 in the downward direction rotating 9cL between the rollers 28° and 29α, curl correction is performed and a flat transfer paper 18 is sent out.

If the transfer paper 18 is curled upward, position the guide plate 27 so that it faces the joint between the hard roller 28 and the upper elastic roller 29b as shown by the broken line, and
The hard roller 28 and the upper elastic roller 29b are rotated so that the relationship is as follows. Transfer the curled transfer paper 18 to both rollers 2.
Curl correction is similarly performed by passing it between 8 and 29b.

The present invention has the above-described configuration, and can provide a curl detection device that can detect curls in a transfer sheet with a simple configuration.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of an electrophotographic copying machine, wis diagram, and Figure 3.
1s4 and i are schematic diagrams of a curl detection device according to each embodiment of the present invention, and FIG. 6 is a schematic diagram of a curl correction device. 18... Transfer paper, 19... Conveyance roller, 2o... Step, 21... Tip of transfer paper, 22... Curl Detection space section, 23...
... Ultrasonic sensor, 24 ... Heating roller, 2
5... Conveyor belt, 26!126b126c・
...Mike stomach switch.

Claims (1)

[Claims] A curl detection space in which the leading edge of the transfer sheet is in an unsupported state is formed in the middle of the conveyance path of the transfer sheet, and a position sensor detects the position of the leading edge of the unsupported transfer sheet facing the curl detection space. A curl detection device for a transfer sheet, characterized in that a curl detection device is provided near a curl detection space.