JPH04298437A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of preventing breakage of a document or photosensitive material by detecting precursory of occurrence of a jam, and stopping the transfer in transferring the document or sheet material of photosensitive material and the like. CONSTITUTION:Rotation of a transfer means 104 for transferring a document C or photosensitive material A is detected by a detection means 112, and transfer of the document C or the like is stopped prior to occurrence of a jam based on a level change of a detection signal Va. The occurrence of the jam can thus be prevented before it occurs, thereby breakage of the document C or the sheet material of the photo-sensitive material can be prevented.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to an image forming apparatus that forms a desired image using a sheet material such as an original or a photosensitive material, and in particular, prevents jamming of the sheet material while the sheet material is being conveyed. The present invention relates to a technique for preventing damage to sheet materials.

0002

2. Description of the Related Art As an image forming apparatus, there is a method of forming an image by overlapping two sheets of material. For example, there is a method in which an exposed photosensitive material and an image-receiving material are overlapped to form an image on the image-receiving material, and a method in which an original and a photosensitive material are overlapped and exposed to form an image on the photosensitive material. In the latter method, the original and the photosensitive material are overlapped on the circumferential surface of a drum-shaped exposure section and exposed, then the original and the photosensitive material are separated, and the photosensitive material is transported to a heated developing drum and developed. is configured to do so. The original and the photosensitive material are overlapped and then conveyed to an exposure section, further conveyed to a peeling section and peeled off, and then the peeled photosensitive material is sequentially conveyed to a developing section or the like. Belts and nip rollers are often used as the conveyance means, and the conveyance path is appropriately provided with detection means for detecting whether or not the original or photosensitive material is being conveyed properly.

Conventional detection means use microswitches or optical sensors to detect the leading and trailing ends of a document or photosensitive material being transported. Further, the feeding operation of originals and photosensitive materials and their transportation to the exposure section, peeling section, developing section, etc. are all controlled by the central controller. If the above-mentioned detection is not performed within the predetermined transit time from when the original or photosensitive material is conveyed from the first detection means to the second detection means and is detected, the detection signal is not transmitted to the central control device. If not,
It was determined that the paper jam had occurred and the document, etc. had stopped.

0004

[Problems to be Solved by the Invention] However, in the conventional detection method, when a delay in conveyance of a document, etc. is detected, it is after a jam has already occurred, and it is likely that the document, etc. is damaged at this point. many. In particular, in the case of a diazo copying machine, etc., the manuscript is often an original handwritten copy, and damage or wrinkles due to jamming can be as fatal as the loss of the manuscript.

The present invention has been made in view of the above-mentioned problems, and its purpose is to:
An object of the present invention is to provide an image forming apparatus that prevents damage to sheet materials such as originals and photosensitive materials by detecting signs of jam occurrence and stopping conveyance.

[0006]

[Means and operations for solving the problems] The above object of the present invention is to provide an image forming apparatus that forms an image using a sheet material, in which a conveying means for conveying the sheet material has a conveying speed of the sheet material. This is achieved by an image forming apparatus that is provided with a detection means for detecting the image forming apparatus and configured to stop the conveyance of the sheet material based on a detection signal obtained from the detection means in accordance with the conveyance speed. That is, when conveying a sheet material such as an original or a photosensitive material, if the sheet material becomes jammed due to some kind of trouble, the nip roller or the like serving as the conveying means also stops rotating. Therefore, by detecting the stoppage of rotation of the nip roller by the detection means and stopping the conveyance or driving of the apparatus, it is possible to stop the conveyance and protect the sheet material before a jam occurs.

[0007] The recording material used as the sheet material in the present invention may be recorded by any recording method. For example, as a recording material, a diazonium salt is coated on a support as described in JP-A-59-190886. There are diazo-sensitive materials which have a genus containing microcapsules, couplers and bases. A latent image corresponding to the original is created by exposure to light and developed by heating.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic explanatory diagram illustrating the detection of jam occurrence, FIG. 2 is a waveform diagram illustrating the detection operation, FIG. 3 is a perspective view illustrating an example of application to a nip roller, and FIG. 4 is a schematic configuration diagram of an image forming apparatus. FIG. 5 is an enlarged view of the main part of the image forming apparatus for explaining the form of jam. In explaining the embodiment, the jam detection operation will be explained with reference to FIG. 1, and then the image forming apparatus will be sequentially explained.

In FIG. 1, a document C is conveyed in the direction of arrow X by a drive belt 1, and a roller 3 is pressed in the direction of arrow Y by a spring or the like (not shown). Therefore, by moving the drive belt 1 in the direction of arrow X, the roller 3
is driven to rotate in the direction of arrow Z. The roller 3 receives driving force from the document C or the drive belt 1, and is not connected to any other driving source. On the other hand, the encoder blade 4 is
It is configured to rotate in conjunction with the roller 3, and the rotation of the encoder blade 4, in other words, the rotation of the roller 3 is detected by the sensor 5.
It is designed to be detected by

When the document C is being transported at a normal speed, the rotational speeds of the roller 3 and the encoder blade 4 do not change, and the detection signal Va obtained from the sensor 5 is as shown in FIG. 2(a).
As shown in period T, the level changes in a pulse-like manner with a constant time width. The detection signal Va is transmitted to a central control device (not shown), and the drive motor that drives the drive belt 1 is operated as shown in FIG.
Continue the rotation as shown in (b). And belt 1
There is no change in the detection signal Va even if the leading edge of the document C is placed on the roller 3 from a state where there is no document C on top, or even if the document C is transported and the roller 3 directly contacts the belt 1. The motor continues to rotate.

However, if the leading edge of the document C gets caught due to some trouble and the advance of the document C is hindered, the belt 1
The upper document C is momentarily stopped. Since the roller 3 rotates as the original C is conveyed, when the original C comes to a halt, the roller 3 also stops. As a result, encoder blade 4
The rotation also stops, and the detection signal Va changes from a pulse signal to a DC signal at a predetermined level, as shown in period Ta in FIG. 2(a). The central processing unit determines that a jam has occurred when the level change becomes equal to or greater than a predetermined time width t, and the central processing unit determines that a jam has occurred.
), the motor is turned off and the device is stopped. Therefore, conveyance of the document C is stopped, and damage due to jam can be prevented.

In this embodiment, the jam detection described above is applied to an image forming apparatus, and the roller 3 and encoder blade 4 are constructed by using a nip roller as shown in FIG. 3. Basically, any nip roller may be used as long as it is provided for conveying a document C or a photosensitive material A, which will be described later. However, in this embodiment, since the nip roller 104 provided near the peeling section 54 shown in FIG. 4 is used, the reference numeral 104 is also given in FIG. 3 for explanation. Note that the nip roller 104 presses the original C that is conveyed by the belt 40 after being separated, and its configuration and operation will be explained later with reference to FIG. 4.

A pattern seal 111 is inserted into one end of the nip roller 104 by inserting a shaft 110 therethrough.
is attached. The pattern sticker 111 has alternating radial striped patterns with different degrees of light reflection. The sensor 112 includes a light emitting element that irradiates the surface of the pattern seal 111 and a light receiving element that receives reflected light, and is fixed at a position where it can irradiate the surface of the pattern seal 111 and receive the light.

Therefore, the detection signal Va obtained from the sensor 112 changes in a pulsed manner while the nip roller 104 is rotating, as described with reference to FIG. 2(a). If a jam is likely to occur with document C, the signal changes to a DC signal as described above, and if the predetermined period t or longer elapses, it is determined that there is a jam and the apparatus is stopped.

Next, an image forming apparatus to which the above detection means is applied will be explained with reference to FIG. FIG. 4 is a schematic configuration diagram of an image forming apparatus, and a diazo photosensitive material is accommodated in a paper feed cassette 2. As shown in FIG. The image forming apparatus includes a document transport section 32 for carrying in and discharging a document C and for repeatedly circulating the same document C within the device, and an exposure section 34 for exposing an image onto a photosensitive material A superimposed on the document C. , a peeling section 54 that peels off the original C and the photosensitive material A after exposure, and a developing section 36 that heats and develops the peeled photosensitive material A.

The document transport section 32 includes a hollow guide drum 38.
A plurality of conveyor belts 40 are arranged around the circumferential surface of the belt 40 in parallel, and another belt 4 is stretched across the belt 40.
2, and by rotationally driving both belts 40 and 42, the document C is held and conveyed. A cassette 21 containing photosensitive material A is loaded below the document transport section 32 . The photosensitive material A in the cassette 21 is transported by the original C.
At the same timing, the sheets are fed one by one to the stacking section 44 by the paper feed roller 30, and are stacked on the document C. The photosensitive material A overlapped with the original C is conveyed by the conveyance roller 31
is transported to the exposure section 34 by.

The exposure section 34 includes an exposure drum 48 containing a fluorescent lamp 46, and is supported by the exposure drum 48 and four belt support rollers 50, and is wound around approximately 3/4 of the circumferential surface of the exposure drum 48. and a belt 52. Then, the exposure drum 48 and the belt 52 are driven to rotate, and while the original C and the photosensitive material A overlapped between the exposure drum 48 and the belt 52 are conveyed, the light from the exposure drum 48 is transmitted. An original image is projected onto the photosensitive material A to form a latent image.

After being exposed, the photosensitive material A is separated from the original C in the separation section 54 and then conveyed to the development section 36. The developing section 36 includes a hollow cylindrical heating drum 58 having a halogen lamp 56 therein, and three conveyance rollers 60 that come into contact with the circumferential surface of the heating drum 58. Conveyance roller 6
A guide member 62 for guiding the photosensitive material A in contact with the circumferential surface of the heating drum 58 is provided between the heating drums 58 and 58 . The photosensitive material A is then heated and developed while being held and conveyed by the heating drum 58 and the conveyance roller 60, and the latent image on the photosensitive material A is visualized. The photosensitive material A after development is discharged from the discharge port 64 and transferred to a stacker 66 provided on the main body case.
are accumulated in

On the other hand, the original C that has been separated from the photosensitive material A is discharged to the outside of the apparatus by the conveyor belt 40, or is circulated along the guide drum 38, and is used for copying through the same process as described above. The guide drum 38 has holes distributed between the conveyor belts in the circumferential area from the peeling section 54 to the document input section, and is equipped with a fan 68 for sucking air inside the guide drum 38 . The original C after peeling is urged by the conveyor belt 40 by the negative pressure inside the guide drum 38, comes into close contact with the conveyor belt 40, and is conveyed by the driving force.

The nip roller 104 is disposed near the peeling section 54, and rotates while pressing the document C being conveyed by the conveyor belt 40. Therefore, while the document C is being transported normally, it is continuously discharged and circulated outside the apparatus. Further, if the document C is caught or jammed, and a jam is likely to occur, the apparatus is stopped in the same manner as described above, and damage to the document C is prevented.

[0021] Here, it is assumed that the above-mentioned jam detection means is not provided and the document C is conveyed with a jam still occurring. In this case, even though the leading edge of the document C is jammed and cannot be conveyed, the trailing edge is being conveyed, so the trailing edge of the jammed document C is deformed and moved toward the developing section 36, as shown in FIG. They end up being transported. However, as in this embodiment, the nip roller 104
By providing a jam detection means in the vehicle, the above-mentioned accident can be prevented. Furthermore, since the nip roller is used, there is no need to specially provide encoder blades or the like as in the conventional case, and the apparatus can be simplified.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. A magnetic material may be attached instead of the pattern seal 111, and the sensor 112 may be replaced with a magnetoelectric conversion element. Also, sensor 1
12 is not limited to the vicinity of the peeling portion 54 described above. Furthermore, multiple units are installed in the conveyance path of original C and photosensitive material A, so that if a problem occurs in one of them,
The device may be configured to be stopped in the same manner as described above.

[0023]

Effects of the Invention The image forming apparatus according to the present invention uses a detection means to detect the conveyance speed of the conveyance means for conveying sheet materials such as originals and photosensitive materials, and when the conveyance speed fluctuates due to trouble, the conveyance means is activated. The structure is designed to protect the sheet material before a jam occurs by stopping the system or stopping the equipment. Therefore, even if a jam occurs, damage to the sheet material can be prevented, and the reliability of the apparatus is improved.

[Brief explanation of drawings]

FIG. 1 is a schematic structural diagram of a transport means and a detection means showing an embodiment of the present invention.

FIG. 2 is a waveform diagram illustrating a jam detection operation.

FIG. 3 is a perspective view of a nip roller, which is an example of a conveyance means, and a detection means.

FIG. 4 is a schematic structural diagram of an image forming apparatus.

FIG. 5 is an enlarged view of a main part illustrating the form of a jam.

[Explanation of symbols]

1 Belt 3 Roller 4 Encoder blade 5,112 Detection means 21 Cassette 34 Exposure section 36 Developing section 44 Overlapping part 46 Fluorescent lamp 48 Exposure drum 50 Belt support roller 104 Nip roller 111 Pattern sticker A Photosensitive material C Manuscript Va detection signal

Claims (1)

[Claims] 1. In an image forming apparatus that forms an image using a sheet material, a conveyance means for conveying the sheet material is provided with a detection means for detecting the conveyance speed of the sheet material, and the conveyance speed is determined from the detection means. An image forming apparatus configured to stop conveyance of the sheet material based on a detection signal obtained in response to.