JP2003327358A - Roll sheet end sensing device, roll sheet supply device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roll sheet end sensing device structured simply and having less risk of missensing. <P>SOLUTION: A continuous sheet 32 is wound round a paper tube (bobbin) 35 to form a supply roll 31 and paid off bit by bit while the supply roll is rotated. The paper tube is furnished at the periphery with a circumferential groove 36. An actuator (sensing member) 37 is supported turnably round a shaft 39, energized by an energizing member to give it a habit to turn, and abutted on the periphery of the supply roll 31. Accordingly the actuator 37 intrudes into the groove 36 when there is no sheet 32. The motion of the actuator is sensed by an end sensor 38 to know that there is no more sheet. It is preferred that the circumferential groove is formed in a position on the paper tube where the least width sheet is wound round. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be applied to an image forming apparatus for recording an image on a sheet such as a sheet of paper or an OHP film, such as a copying machine, a printer, a facsimile, or a complex machine thereof. In addition, the present invention relates to a roll sheet supply device in which an continuous sheet is wound around a core tube such as a paper tube to form a supply roll in such an image forming apparatus, and the continuous roll is sequentially fed while rotating the supply roll. In addition, the present invention relates to a roll sheet end detection device that detects that there is no continuous sheet in such a roll sheet supply device.

[0002]

2. Description of the Related Art Conventionally, among the roll sheet end detecting devices provided in a roll sheet feeding device, there have been the followings. As described in Japanese Patent Laid-Open No. 7-196235, the encoder is pressed against the driven roller of the pair of conveyance rollers that convey the continuous sheet fed from the supply roll, and the drive roller is rotating. When the encoder stops, it detects it and detects the end of the continuous sheet.

As described in Japanese Patent Application Laid-Open No. 9-290951, the surface of the paper tube of the supply roll is made black, and a light emitting and receiving sensor is provided facing the supply roll.
When the surface of the paper tube appears and the light receiving voltage of the light emitting and receiving sensor falls below the threshold value, it is judged as the end of the continuous sheet.

An actuator is pressed against a continuous sheet stretched between a supply roll and a pair of conveyance rollers for conveying the continuous sheet fed from the supply roll, and the operation of the actuator is detected, so that the continuous sheet is exhausted. What detects.

[0005]

However, any of the roll sheet end detection devices (1) to (3) has a problem that the structure is complicated and there is a risk of erroneous detection.

SUMMARY OF THE INVENTION Therefore, a first object of the present invention is to provide a roll sheet end detection device which has a simple structure and detects the absence of a continuous sheet without fear of erroneous detection.

A second object of the present invention is to provide a roll sheet end detecting device which has a simple structure and is less likely to be erroneously detected, and which can detect the sheet ends of continuous sheets of all sizes having different widths. It is in.

A third object of the present invention is to provide a roll sheet end detecting device which has a simple structure and is less likely to be erroneously detected, and which can detect the sheet end of a continuous sheet wound around a core tube on the basis of an end face. Especially.

A fourth object of the present invention is to provide a roll sheet end detecting device which has a simple structure and is less likely to be erroneously detected and which can detect the sheet end of a continuous sheet wound around a core tube with a central reference. Especially.

A fifth object of the present invention is to provide a roll sheet feeding device provided with a roll sheet end detecting device which achieves the above objects.

A sixth object of the present invention is to provide an image forming apparatus equipped with a roll sheet feeding device which achieves the fifth object.

[0012]

Therefore, in order to achieve the first object, the invention described in claim 1 forms a supply roll by winding a continuous sheet around a core tube, and rotates the supply roll. While in the roll sheet end detection device in the roll sheet feeding device that sequentially feeds out continuous sheets, a circumferential groove is formed on the outer circumference of the core tube, and a detection member that enters the circumferential groove when the continuous sheet runs out is provided on the outer circumference of the supply roll It is characterized by pressing.

According to a second aspect of the present invention, in order to achieve the second object, in the roll sheet end detection device according to the first aspect, the core tube is circumferentially wound at a position around which the continuous sheet having the minimum width is wound. It is characterized in that a groove is formed.

According to a third aspect of the present invention, in order to achieve the third object, the roll sheet end detecting device according to the second aspect is characterized in that a continuous sheet is wound around the core tube on the basis of the end face. It is characterized by

According to a fourth aspect of the present invention, in order to achieve the fourth object, the roll sheet end detecting device according to the second aspect is characterized in that a continuous sheet is wound around the core tube with a central reference. .

According to a fifth aspect of the present invention, in order to achieve the fifth object, the roll sheet end detection device according to any one of the first to fourth aspects is provided, and a roll sheet supply is provided. It is a device.

According to a sixth aspect of the present invention, there is provided an image forming apparatus including the roll sheet feeding device according to the fifth aspect in order to achieve the sixth object.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a main part of an industrial analog wide width copying machine which is an example of an image forming apparatus.

Reference numeral 10 in the drawing denotes a drum-shaped photosensitive member which rotates clockwise in the drawing. Around the photoconductor 10,
From the charging charger 11 arranged at the upper part, the developing roller 12, the transfer charger 13, the separation charger 14, the cleaning blade 15, and the charge eliminating lamp 16 are sequentially rotated clockwise.
To place.

Above the photoconductor 10, a document transport roller 1 is provided.
7 and 18 are provided to form a document transport path for transporting the document 20 in the arrow a direction. Then, along the document transport path,
A document registration sensor 21 and a document image reading device 22 are arranged. The original image reading device 22 is provided with an irradiation lamp 23 and an optical system 24.

On the other hand, sheet conveying rollers 26 and 27 are provided below the photoconductor 10, and a continuous sheet 32 fed from a supply roll 31 of a roll sheet supply device 30 is exposed between the photoconductor 10 and the transfer charger 13. A sheet conveyance path is formed between the body 10 and the separation charger 14 and conveyed in the direction of arrow b. A cutter 33 is provided between the sheet conveying rollers 26 and 27 along the sheet conveying path, and a fixing device 34 is arranged downstream.

When a copy is to be made using this copying machine, the original 20 to be copied is inserted, the start switch is turned on, and the original conveying rollers 17 and 18 are rotated to convey the original through the original conveying path. , Irradiation lamp 2
At 3, the surface of the original is irradiated with light and the reflected light is entered into the optical system 24, and the original image reading device 22 reads the image information on the original 20.

On the other hand, when the start switch is turned on,
The photoconductor 10 is rotated at a timing, the surface of the photoconductor 10 is uniformly charged by the charging charger 11, and then writing is performed by the reading light from the document image reading device 22 to form an electrostatic latent image. Then, toner is attached by the developing roller 12 to develop the electrostatic latent image, and a toner image is formed on the photoconductor 10.

Then, at the timing of aligning with the toner image on the photoconductor 10, the sheet conveying rollers 26.
The continuous sheet 32 fed from the roll sheet supply device 30 by rotating 7 is fed between the photoconductor 10 and the transfer charger 13, and the transfer charger 13 transfers the toner image on the photoconductor 10 to the continuous sheet 32.

After the image transfer, the continuous sheet 32 is separated from the photoconductor 10 by the separation charger 14 and placed in the fixing device 34, and heat and pressure are applied by the fixing device 34 to fix the transferred image on the continuous sheet 32. After that, the cut sheet after being cut into a desired length by the cutter 33 is discharged.

On the other hand, with the rotation of the photoconductor 10 after the image transfer, the cleaning blade 15 removes the residual toner remaining on the surface after the image transfer, and the charge removal lamp 16 removes the charge to start charging again. Prepare for image formation.

By the way, in the illustrated copying machine, the supply roll 31 of the roll sheet supply device 30 has a paper tube 35 which is a core tube.
A continuous sheet 32 is wound around the continuous sheet 32, and the continuous sheet 3 is supported while rotating clockwise in FIG.
Roll out 2. As shown in FIGS. 2 (A) and 2 (B), the paper tube 35 has, for example, a circumferential groove 36 on the outer circumference at the center in the width direction.
To form.

As shown in FIG. 3, an actuator (detection member) 37 is rotatably supported about a support shaft 39, and is biased by a biasing member (not shown) to rotate clockwise in the figure. And is pressed against the outer circumference of the supply roll 31. As a result, when the continuous sheet 32 runs out,
As shown in FIG. 4, the tip of the actuator 37 is inserted into the circumferential groove 36 of the paper tube 35. Then, a roll sheet end detection device 40 that detects the operation of the actuator 37 by an end sensor 38 such as a photo interrupter and detects that the continuous sheet 32 is gone is configured.

In this way, the actuator 37 enters the circumferential groove 36 to increase the rotation angle of the actuator 37 when the continuous sheet 32 disappears, and it is clear whether the continuous sheet 32 is present or not. It is possible to detect that there is no continuous sheet without the risk of false detection by simplifying the structure.

In the illustrated example, as can be seen from FIG.
The rear end of the continuous sheet 32 was glued to the paper tube 35. However, according to the present invention, even when the rear end of the continuous sheet 32 is not attached to the core tube, a circumferential groove is similarly formed on the outer circumference of the core tube, and when the continuous sheet runs out, the actuator enters into the circumferential groove. The same effect can be obtained by pressing a detection member such as the above to the outer circumference of the supply roll.

In the above example, the circumferential groove 36 is formed in the widthwise center of the paper tube 35. However, the circumferential groove 36
By forming the continuous sheet 32 of the minimum width on the paper tube 35 at a position where the continuous sheet 32 is wound, the sheet end of the continuous sheet 32 of all sizes can be detected.

For example, as shown in FIG. 5, when the continuous sheet 32 is wound around the paper tube 35 on the basis of the one end face L in the width direction, the continuous sheet 32a having the minimum width is shaded at a position where the continuous sheet 32a is shaded. The groove 36 is formed.

Further, as shown in FIG. 6, when the continuous sheet 32 is wound around the paper tube 35 with the center C in the width direction as a reference, the continuous sheet 32a having the minimum width is shaded at the position where the continuous sheet 32a is shaded in the drawing. The groove 36 is formed.

In this way, instead of the continuous sheet 32a having the minimum width, the continuous sheet 32 having the medium width is attached to the paper tube 35.
The sheet end can be detected both when b is wound and when a large number of continuous sheets 32c are wound.

[0035]

As described above, according to the first aspect of the present invention, the circumferential groove is formed on the outer circumference of the core tube, and the detection member is pressed against the outer circumference of the supply roll to eliminate the continuous sheet. At that time, since the detection member is inserted into the circumferential groove, the operating range of the detection member when the continuous sheet runs out is increased, and the case where there is a continuous sheet is clearly distinguished, and the structure is simplified. It is possible to reliably detect that there is no continuous sheet without fear of erroneous detection.

According to the second aspect of the present invention, since the circumferential groove is formed in the core tube at the position where the continuous sheet having the minimum width is wound, the structure is simplified, the risk of erroneous detection is reduced, and all the different widths are used. It is possible to detect the sheet end of a continuous sheet of the size.

According to the invention of claim 3, since the continuous sheet is wound around the core tube on the basis of the end face, the structure is simplified,
There is little risk of erroneous detection, and it is possible to detect the sheet end of continuous sheets of all sizes wrapped around the core tube on the basis of the end face.

According to the invention of claim 4, since the continuous sheet is wound around the core tube with reference to the center, the structure is simplified,
There is little risk of erroneous detection, and it is possible to detect the sheet end of continuous sheets of all sizes wrapped around the core tube with the central reference.

According to the invention of claim 5, since the roll sheet end detection device according to any one of claims 1 to 4 is provided, the roll sheet supply device provided with the roll sheet end detection device having each of the above effects. Can be provided.

According to the invention of claim 6, since the roll sheet supply device of claim 5 is provided, an image forming apparatus provided with the roll sheet supply device having the effect of the invention of claim 5 is provided. can do.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of an industrial analog wide copying machine which is an example of an image forming apparatus.

FIG. 2 is a supply roll used in a roll sheet supply device provided in the copying machine, in which (A) is a side view thereof and (B) is a longitudinal sectional view thereof.

FIG. 3 is a side view of the roll sheet feeding device.

FIG. 4 is a side view of the roll sheet feeding device in a state where there are no continuous sheets.

FIG. 5 is an explanatory diagram showing a state in which continuous sheets of various sizes are wound around the paper tube of the roll sheet feeding device with the end face as a reference.

FIG. 6 is an explanatory diagram showing a state in which continuous sheets of various sizes are wound around a paper tube of the roll sheet feeding device with a center reference.

[Explanation of symbols]

30 roll sheet feeder 31 supply roll 32 continuous sheets 32a Minimum width continuous sheet 32b Medium width continuous sheet 32c Large continuous sheet 35 Paper tube (core tube) 36 circumferential groove 37 Actuator (Detection member) 38 End sensor 39 spindle 40 Roll sheet end detector L One end of continuous sheet C Center of continuous sheet

Claims (6)

[Claims] 1. A roll sheet end detection device in a roll sheet feeding device, wherein a continuous sheet is wound around a core tube to form a supply roll, and the continuous roll is sequentially fed while rotating the supply roll. A roll sheet end detection device, wherein a peripheral groove is formed, and a detection member that enters the circumferential groove when the continuous sheet runs out is pressed against the outer circumference of the supply roll. 2. The circumferential groove is formed in the core tube at a position where a continuous sheet having a minimum width is wound.
The roll sheet end detection device according to claim 1. 3. The roll sheet end detection device according to claim 2, wherein a continuous sheet is wound around the core tube on the basis of an end face. 4. The roll sheet end detection device according to claim 2, wherein a continuous sheet is wound around the core tube with a central reference. 5. A roll sheet feeding device, comprising the roll sheet end detection device according to claim 1. 6. An image forming apparatus comprising the roll sheet supply device according to claim 5.