JPH0650413B2 - Image processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image processing apparatus capable of multiple transfer and multiple recording, and a color electrophotographic apparatus, multiple recording apparatus, and electrophotography having a multiple transfer function. The present invention relates to an image processing apparatus that performs transfer of an apparatus or reading of a document.

(Prior Art) In the field of electrophotographic color copying machines, a gripper is provided on a transfer material conveying means called a transfer drum, and the tip side of the gripper transfer material is gripped, and the transfer material is transferred to the transfer position of the photoconductor several times. Techniques for transporting are known. Further, in recent years, an apparatus for transferring a toner image formed on a photoconductor by superimposing a transfer material on the same paper surface has appeared.

When supplying a transfer material to a transfer drum having a limited circumference as described above, conventionally, the size of the transfer material that can be applied is regulated by a paper feed cassette, a paper feed texture, etc. Had a tool that did not send it to the transfer section. However, due to the diversification of transfer materials and market demands, we hope that we will not select transfer materials, and in order to meet this demand, we will consider the use of so-called "handing" paper feeding mechanism so that we can guide any transfer material to the transfer section. To be

(Problems to be Solved by the Invention) Although such a manual paper feeding mechanism can control the transfer material in a direction perpendicular to the conveying direction, the length along the conveying direction is There are no restrictions on use.
For example, the circumference of a transfer drum with a diameter of 120 mm is 37
Even though the length of the transfer material is 7 mm, even if the transfer material of A3 size (JIS standard) is wound around the transfer drum with the longitudinal direction of the transfer material being 420 mm, the length of the transfer material is 420 mm. The front end of the transfer material, which is gripped by the gripper, will overlap. As a result, good separation becomes impossible when the predetermined transfer process is completed.

The present invention has been made in view of the above, and an object of the present invention is to provide an image processing apparatus that can prevent defective image processing and defective separation of a sheet from a rotating body that winds and conveys a sheet material.

(Means for Solving the Problems) A configuration of the present invention that achieves the above object is to wrap a sheet material, and to a rotating body that repeatedly conveys in a predetermined endless conveying path, and to a sheet material wound around the rotating body. An image processing unit that repeatedly performs image processing, a supply unit that supplies a sheet material to the rotating body, a detection unit that detects a conveyance direction length of the sheet material supplied by the supply unit, and a detection unit that detects the sheet material. An image processing apparatus, comprising: a control unit that prohibits image processing by the image processing unit when the length of the sheet material exceeds a predetermined allowable range that does not exceed the circumferential length of the rotating body. Is.

(Embodiment) FIG. 2 is a schematic cross-sectional view of an electrophotographic color recording apparatus in which the present invention is applied to a transfer apparatus as an image processing apparatus and has a step of transferring color toner to a transfer material as a prescribed step. It is a figure. An electrophotographic method is applied to the photosensitive drum 1 to form a latent image. In the figure, a latent image is formed on a drum 1 by a charger 2 and an optical system 3 for scanning a laser beam corresponding to a color separation image, and a yellow Y, a magenta M, a cyan C and a black K are formed.
The latent images formed by the developing device 4 which rotates and replaces each color developing device are sequentially developed.

On the other hand, the transfer drum 5 as a rotating body is provided with a known gripper in a part of its drawing, and grips and rotates the front end of the transfer material conveyed from the paper feed cassette 6 or the hand tray 7. , The same surface of the transfer material is conveyed to the transfer position multiple times. The toner image on the photosensitive drum is transferred onto the transfer material by the corona discharger 8, and after transferring the color toner a predetermined number of times (for example, yellow, magenta, cyan), the transfer material is separated by the separation claw 9 and the fixing device. The sheet reaches 10 and is discharged onto the sheet discharge tray 11 after fixing.

Here, the effective output length of the transfer drum 5 (the maximum length with which the transfer material gripped by the gripper can correctly complete the transfer process) is L ₁ . This L ₁ is almost equal to the circumference of the transfer drum 5. It goes without saying that the transfer material fed at this time has a length L ₁ or less. If a transfer material longer than the length L ₁ is handled and fed from the tray, the trailing end of the transfer material overlaps the gripper and the correct separating operation is hindered.

Therefore, in this embodiment, two sensors a and b serving as detecting means are attached in the conveyance path, and the distance L ₂ between the sensors is L ₂ .
The relationship was ₁ L ₂ . On the other hand, the transfer position and the sensor b are L ₃ , and the distance from the exposure position of the photosensitive drum 1 to the transfer position on this drum is L ₄ . The distance to the transfer position on this drum is L ₄ . At this time, the distances L ₃ and L
₄ of the _{relationship,} the _L 3> L ₄ and Mitsurusu ones.

When the rear end of the transfer material is still passing through the sensor a when the transfer material is conveyed to the position of the sensor b under the above setting conditions, and the length of the supplied transfer material is L, the distance L The relationship between ₂ and L is L ₂ <L, and in the relationship with L ₁ L ₂ above. In some cases, the length of the transfer material may exceed the effective output length of the transfer drum 5. Therefore, in such a case, the exposure and development operations are stopped to prevent wasteful image formation.

The stop of the image forming process is determined based on the output of the sensor a. When it is decided to stop the image formation as described above, the transfer material is conveyed to the separation claw 9 using the transfer material drum 5, and is discharged onto the discharge tray 11 by the separation claw 9. However, in the case of monochromatic development such as black, it does not matter even if an image is formed.

With the above configuration, it becomes possible to cope with the next supply of the transfer material without stopping the apparatus. Also, no special exclusion configuration is required.

Next, a specific control method of the above processing will be described with reference to FIG.

At steps 101 to 103 shown in the figure, a transfer material is supplied from the hand tray 7 or the cassette 6 and held on the transfer drum 5. Next, in step 104, the tip of the transfer material blocks the sensor b and waits until the output is turned on. When the output is turned on, the output of the sensor a is checked in step 105. If the output is off at this time, it means that the trailing edge of the transfer material has passed the sensor a, and steps 106 and 107 perform image formation a necessary number of times. On the other hand, in step 105, the sensor a
Is ON, if single development is designated by means not shown in step 111, that is, which of yellow (Y), magenta (M), cyan (C), and black (K) shown in FIG. The branching step differs depending on whether or not is specified. For example, in the single-color development mode, it is not necessary to wind the transfer material around the transfer drum and rotate the transfer material a plurality of times, so that branching to step 106 is possible. On the other hand, when two or more developing colors are required, for example, the red requires two developing colors (Y) and (M), so the transfer drum rotates at least two times or more until the transfer process is completed. Since the trailing edge covers the transfer drum for one round or more, a part of the output image may be defective, or image processing failure may occur, or separation may become impossible. "Not suitable" is output to a display unit such as a main body operation panel (not shown) and branched to Step 108. That is, without performing the image forming step, the transfer material is separated by the separation claw 9 in the same manner as the above-described single color transfer without transferring anything to the transfer material. Step 10
In steps 8 to 110, after separation, fixing and discharging are performed, and the entire image forming process is completed.

In the description of FIG. 2 above, the length of the transfer material fed by the two sensors a and b is detected, but the same effect can be obtained by using one sensor.
In FIG. 3, when the distance from the sensor c to the transfer position along the conveyance path is L ₅ , the above-mentioned distances L ₁ and L _{4 are given.}
The sensor c is placed at a position where the relationship of L ₁ + L ₄ L ₅ is established in the transfer material conveying path indicated by. With the above configuration, the number of pulses from a pulse source, for example, a pulse encoder connected to a feed roller or a drive motor, which is generated in synchronization with a conveying speed (not shown) after the front end portion of the transfer material is detected by the sensor c is counted, and the distance L When the counted number of pulses N ₁ corresponding to ₁ again examine the output of the sensor c, if as if part of the transfer material is still present, that the transfer material has exceeded a predetermined length It has been detected. Then, thereafter, as shown in the control method of FIG. 1, the transfer material supported on the transfer drum 5 is forcibly removed from this drum at the separation position without being subjected to the image forming process, and is sent onto the discharge tray 11. .

If there is only one sensor c, the same state will be obtained even if the transfer material causes retention jam at the position of the sensor c.
In such a case, it is possible not only to stop the image output but also to stop the conveyance of the transfer material itself and treat it as a jam without using the control method shown in the flow chart of FIG. Therefore, it is not preferable to stop the main body device.

As another embodiment of the present invention described above, for example, a drum sheet type reading device capable of reading an original by gripping the original as a sheet material on a rotary drum, or a recording paper conveying section of a drum rotary type ink jet device. It is also possible to apply to. In the former case of this modified example, the prescribed step is a reading step, and the transfer means in FIG. 2 is replaced with an optical means such as a contact sensor or a condenser lens and a light receiving element, and in the latter case, the transfer means in FIG. The transfer means may be replaced with an ink jet recording head. The means for transporting such a sheet material is not limited to the drum, and may be an endless moving transport means such as a chain or a belt. As a method of supporting the sheet material on the conveying means that moves endlessly, it is possible to use not only the gripper but also electrostatic attraction or suction force by back pressure.

(Effects of the Invention) As described above, according to the present invention, when the length of the sheet material exceeds a predetermined allowable range, image processing is prohibited.
It is possible to prevent defective image processing and defective separation of the sheet from the rotating body.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining a control example of the present invention, FIGS. 2 and 3 are schematic explanatory diagrams of an apparatus to which the present invention is applied, and FIG. 4 is a flow chart for explaining a control example of another embodiment. It is a figure. In the figure, 1 is a photosensitive drum, 5 is a transfer drum, 8 is a corona discharger for transfer, 9 is a separation claw, 11 is a discharge tray, and a
~ C shows a sensor.

Claims (4)

[Claims] 1. A rotator that winds a sheet material and repeatedly conveys the sheet material in a predetermined endless conveyance path; an image processing unit that repeatedly performs image processing on the sheet material wound around the rotator; Supply means for supplying the sheet material, detection means for detecting the length in the conveying direction of the sheet material supplied by the supply means, and the length of the sheet material detected by the detection means exceeds the circumferential length of the rotating body. An image processing apparatus, comprising: a control unit that prohibits image processing by the image processing unit when a predetermined allowable range is exceeded. 2. The control means separates the sheet material from the rotating body when the length of the sheet material detected by the detection means exceeds a predetermined allowable range. The image processing apparatus according to item 1. 3. The rotating body is provided with a gripper for gripping the front end of the sheet material, and the allowable range of the sheet material is within a length such that the rear end of the sheet material does not overlap this gripper. The image processing apparatus according to claim 1. 4. The image processing apparatus according to claim 1, wherein the predetermined allowable range is within a circumference of the rotating body.