JPS6278577A - Transfer material detecting device - Google Patents

Abstract

PURPOSE:To maintain a good output image with using minimum sensors by giving the function of detecting image output signals and a function detecting the state of jamming of a carried transfer material in common to the detector of transfer material. CONSTITUTION:Image signals are inputted to an image forming device Pa by the detection signal of a detector 60a. The image signals are inputted to an image forming device Pb by the detection signal of a detector 60b, inputted to Pc by the signal of 60c, and inputted to Pd by the signal of 60d. On the other hand, time between the detection signal of the detector 60a and the detection signal of the detector 60b is measured, and compared to see whether the value is within a fixed set time. For instance, when time measuring is started by the detection signal of the detector 60a, no detection signal is given from the detector 60b even after the lapse of a fixed set time, it is judged that the jamming of transfer material is occurred. Similar procedure is executed for succeeding image forming devices Pb, Pc, and the detection of jamming of transfer material as well is made simultaneously with the detection of the tip part of transfer material at every image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention pertains) The present invention relates to a multi-hair image forming apparatus that is obtained by transferring toner images of a plurality of patterns developed with toner onto the same transfer material.

More specifically, for example, several 8I photoreceptor drums are arranged side by side, and these photoreceptor trams are charged, exposed, developed, transferred, etc., and the images of each color are sequentially transferred to a transfer material conveyed by a belt. In multicolor electrophotographic equipment that performs multi-color electrophotography and multi-transfer equipment that transfers multiple patterns in layers,
This relates to the function of a transfer material detector installed close to the transfer material conveyance belt.

(Prior art) Conventionally, a color image copying device using a multicolor electrophotographic method has two
Methods 3 to 3 have been devised and commercialized, and the method shown in FIG. 2 is also one of the representative methods. In this system, as is clear from the figure, each of the first to fourth image forming apparatuses Pa, P
b, Pc.

Dedicated photosensitive drums la, lb, and lc for each Pd.

ld, and around it are respective dedicated latent image forming parts 2a.
, 2b, 2e, 2d, developing section 3a.

3b, 3c, 3d, transcription? %4a, 4b,
4C.

4d, Cleaning! f85a, 5b, 5c, and 5d are arranged.

First, the latent image forming section 2a of the first image forming apparatus Pa forms a latent image of the yellow component color of the original image on the photoreceptor drum la by a known method, and then the developing section 3a develops a latent image with yellow toner. A visible image is formed by the agent, and the transfer unit 4
The yellow toner image is transferred to the transfer member 6 at step a.

On the other hand, while this yellow image is being transferred, a latent image of magenta component color is formed in the first image forming apparatus Pa, and then a toner image of magenta toner is obtained in the developing section 3b, and the first image is formed. When the transfer material 6 whose transfer has been completed in the apparatus Pa is carried into the transfer section 4b of the second image forming apparatus Pb, this magenta toner image is transferred to a predetermined position on the transfer material 6.

Thereafter, when image formation is completed in the same manner for cyan and black colors, the images are fixed in the fixing section 7, and a multicolor image is obtained on the transfer material 6. After the transfer, the remaining toner is removed from each photosensitive drum by cleaning sections 5a, 5b, 5c, and 5d, in preparation for the next latent image formation to be performed subsequently.

(Problems to be Solved by the Invention) In this type of device, the transfer material 6 is conveyed by the conveyor belt 8, so as described above, the leading edge of the transfer material is detected and the image signal in the next image forming device is detected. A detector is required to control the input timing. On the other hand, similar to the conventional copying machine process, in the transfer 9 separation process, it is possible that the transfer material may jam, and it is necessary to also install a jam detector for these jams.

For this reason, when four image forming apparatuses are used as in the present invention, the number of detectors corresponding to each of these apparatuses must be increased. This is not desirable in terms of cost, frequency of detector adjustment, and reliability.

The object of the present invention is to propose a new transfer material detection device that improves the problems of the conventional method described above. At the same time, such a detection device provides a detection device that can be easily and inexpensively realized without using many expensive and sophisticated parts.

(Means for Solving the Problem) The transfer material detection device of the present invention uses a transfer material detector installed close to the transfer material conveyance belt to detect the image output signal and the jam state of the conveyed transfer material. It also serves as a detection function. That is, the above configuration makes it possible to maintain a good output image with a minimum number of sensors. In addition,
This concept of jam also includes skewing of the transfer material in the sense of inconvenient paper feeding.

(Example) A specific example of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a sectional view showing an embodiment of the present invention. The apparatus of this embodiment incorporates four sets of electrophotographic laser beam printer mechanisms as a plurality of sets of image forming apparatuses. In the figure, reference numeral 10 denotes a main unit box of the apparatus, and numerals Pa, Pb, Pc, and Pd indicate four sets of image forming apparatuses arranged sequentially from the right side to the left side in the figure. ll is a conveyor belt drive roller that is rotationally driven by a drive source (not shown). A conveyor belt 8 is suspended around the conveyor belt drive roller 11 .

This conveyor belt 8 is made of a mesh of Tetoron fibers, and is moved by a drive roller 11 in the direction of the arrow in the figure. Reference numeral 13 indicates a paper feeding mechanism disposed on the right side of the machine frame, numeral 7 indicates an image fixing roller disposed on the left end side, and numeral 14 indicates an outlet for discharging the transfer member to the outside of the machine.

The mechanical configurations of the image forming apparatuses Pa, Pb, Pc, and Pd are substantially the same.

That is, each image forming apparatus has axes 8a, 8b, and 8c, respectively.

Photosensitive drums la, lb, lc, and ld as image carriers are driven to rotate in the direction of the arrow about 8d, and chargers 15a and 15i are sequentially arranged around the drums in the drum rotation direction.
5b, 15c.

15d, developing devices 3a, 3b, 3c, 3d, transfer discharge devices 4a, 4b, 4c, 4d, cleaning devices 5a, 5b,
5c, 5d, and a laser beam scanner 16a placed above the photosensitive drum.

It consists of 16b, 16c, and 16d. The laser beam scanner consists of a semiconductor laser, a polygon mirror, an FO lens, etc., and includes a charger 15a that receives a digital pixel signal and emits a laser beam modulated in accordance with the signal.

15b, 15c, 15d and developing units 3a, 3b.

3c'+3d to expose the drum surface by scanning in the direction of the tram bus line.

Further, the developing device 3a of the first image forming apparatus Pa is filled with yellow toner, and the second developing device 3a is filled with magenta toner.
The third one contains cyan toner, and the fourth one contains black toner. The laser beam scanner 16a of the first image forming apparatus Pa receives a pixel signal corresponding to the yellow component image of the color image, the second image forming apparatus Pb receives a signal corresponding to the magenta component image, and the third image forming apparatus Pb receives a pixel signal corresponding to the yellow component image of the color image. A signal corresponding to the cyan component image is input to the device Pc, and a signal corresponding to the black component image is input to the fourth device Pd.

Now, the cut sheet-like transfer material 6 is transferred to the paper feed guide 511 of the paper feed mechanism 13 as a transfer material. When the image forming apparatus Pa is inserted into the image forming apparatus Pa, the tip thereof is detected by the sensor 52, and this start signal causes each image forming apparatus Pa to be activated.

Pb, Pc, Pd photosensitive drums la, lb.

lc and ld start rotating. The drive roller 11 is also driven at the same time, and the conveyor belt 8 also begins to run in the direction of the arrow. The transfer material 6 passes through a paper feed guide 57 and is supplied to a conveyor belt 8. Thereupon, the transfer material 6 receives corona radiation 1k from the adsorption charger 59.

Reliably adsorbs onto the conveyor belt 8.

Furthermore, the tip of the transfer material 6 is each sensor 60a.

When 60b, 60c, and 60d are shut off, each image forming apparatus Pa, Pb, and Pc receives the signal.

Each pre-rotating photosensitive drum la of Pct.

Image formation for lb, lc, and ld starts sequentially. That is, a yellow image is produced on the photosensitive drum la of the first image forming apparatus Pa, a magenta image is produced on the second apparatus pb, a cyan image is produced on the third apparatus Pc, and a black image is produced on the fourth apparatus Pd. They are formed by sharing their respective roles.

The image forming principle in each image forming apparatus δ is already well known as the Carlson process, so its explanation will be omitted. Then, the transfer material 6 is moved toward the fixing roller 7 by the rotation of the conveyor belt 8 to the first to fourth image forming apparatuses Pa, Pb,
The transfer material 6 is conveyed sequentially passing through the lower parts of Pc and Pd, and is transferred to the transfer material 6 by the transfer centering devices 4a, 4b, 4c, and 4d of each device.
Then, each color is sequentially superimposed and transferred to form a color image. When the transfer material 6 passes through the fourth image forming apparatus Pd, the static electricity is removed by a static eliminator 61 to which an AC voltage is applied, and W
It is separated from the feed belt 8.

Next, the transfer material 6 enters the fixing roller 7, the image is fixed, and is discharged outside the machine from the outlet 14, completing one print cycle.

In the present invention, the same detectors 60a and 60b are used to detect the leading edge of the transfer material and to detect the jam of the transfer material.

This is done by 60c, 60d, and 60e.

For ease of explanation, transfer material conveying belt 8°
Toram 1a, I image rff 13a, roll-'j part 4a
etc. are extracted and shown in Figure 1. Other image forming apparatus Pb
, Pc, and Pd have exactly the same configuration.

Detectors 'B60a and 60b have an integrated structure with an infrared LED and a light receiving section that receives the reflected light.In order to accurately detect the leading edge of the transfer material, the light is directed to the transfer material by the lens system at the detector's tip. The light is focused at position 20. When the transfer material 6 is conveyed to this position 20, the leading edge is detected by a change in the reflected light. In the example, the detection accuracy is ±150go>
The setting j6 distance 921 of the detector 60a is the photosensitive drum 1.
- corresponds to the distance between the exposed part and the transfer part. Further, since a known circuit is already used for this electrical processing method of the detector output, a description thereof will be omitted. And this detector 60
An image signal is manually input to the image forming apparatus Pa based on the detection signal a.

Thereafter, an image signal is manually inputted to the image forming apparatus Pb at the detection number 4.3 of the detector 60b, to Pc at 60C, and to Pd at 60d.

- On the other hand, in this embodiment, another circuit (not shown) measures the time between the detection signal of the detector 60a and the detection signal of the detector 60b. As this circuit is already a known circuit as described above, its explanation will be omitted. Then, a comparison is made to see if this I+6 has been entered within a certain set time. This setting value is determined by the conveyor belt speed and detector 6.
It is determined by the distance between 0a and 60b.

For example, if time measurement starts with a detection signal from the detector 60a, and there is no detection signal from the detector 60b even after a predetermined period of time has elapsed, it is determined that a jam of the transfer material has occurred.

Thereafter, the process is similarly carried out for the next image forming apparatuses Pb and Pc, and a jam of the transfer material is also detected at the same time as the leading edge of the transfer material is detected for each image forming apparatus. In the case of the last image forming apparatus Pd, the determination is made by the detector 60d and the detector 60e on the discharge side of the fixing device.

(Other examples) FIG. 4 shows another embodiment of the invention.

In the previous embodiments, when the transfer material jammed, it was difficult to determine its position, but in this embodiment, it is possible to detect the wrapping of the transfer material around the photosensitive drum due to poor separation.

In this embodiment, the detector 60b is set at the position shown in FIG. Assuming that the distance between the photosensitive drums la and lb is 110 mm and the diameter of the photosensitive drum is 60 mm, the detector 60b is set at position 25 in the figure from the relationship of one image input timing.

This position is convenient for determining whether the film is wrapped around the photosensitive drum.

That is, when the transfer material adheres to the photosensitive drum side, the detector 60b
The reflected light to the transfer material conveyance belt 8J:.

Although the amount of reflected light is reduced compared to when the transfer material 6 is in close contact with the surface, the amount of reflected light is increased compared to the case where no transfer material exists at all.

For this reason, the output comparison level of the detector 60b is set to 3.
You can set it up in stages and compare. In an experiment using white paper as a transfer material, a large amount of reflected light was obtained, so it was confirmed that comparative judgments on three levels could be easily made.

By the method described above, it is possible not only to simply detect a jam in the transfer material but also to determine the position of the jam. This judgment information can also be confirmed by displaying it on the operation panel of the main body of the copying machine.Although a photosensitive drum was used as the image carrier in Example L, it is also possible to use a multi-stylus or modulated ion stream. An insulated drum that forms a latent image may be used, and its shape is not limited to a drum, but may also be a belt. Further, the apparatus to which the present invention is applied is not limited to a color copying machine, but may also be an image forming apparatus such as a printer that superimposes a plurality of images using toner of the same color.

(Effects of the Invention) As described in ``2'' below, according to the present invention, one detector is installed for each image forming apparatus without providing separate detectors for detecting the leading edge of transfer material and detectors for detecting transfer jam. Just by making these 100 or so calculations, Otogon is mountain-shaped ^, -kL
1 (It goes without saying that this makes it easy to reduce the frequency of detector adjustment, downsize and simplify the device, and greatly contributes to cost reduction.

[Brief explanation of drawings]

Figure 1 shows the detector, transfer material conveyance belt, and
An explanatory diagram of the positional relationship and structure of photosensitive drums, etc., FIG. 2 is a vertical cross-sectional view of a typical structure of a multicolor electrophotographic copying device, and FIG.
The figure is a longitudinal cross-sectional view of the detailed structure of a multicolor electrophotographic copying apparatus according to an embodiment of the present invention, and FIG. 4 shows a partial cross-section [4] of a transfer section illustrating another embodiment of the present invention. (In 4, 1 a , 1 b , 1 c ,
td is a photosensitive 1'ram; 4a, 4b, 4c, and 4d are transfer sections; 6 is a transfer material; 8 is a transfer section conveyor belt; 60a; 60b, 60c, 60d, and 60e indicate detectors.

Claims (1)

[Claims] Latent images of different patterns are formed on a plurality of image carriers, and the toner images visualized by development are sequentially superimposed and transferred onto a transfer material conveyed by a transfer material conveyance belt to obtain multiple images. In a multiple image forming apparatus, a detector installed close to the transfer material conveyance belt is equipped with a function to detect the leading edge of the transfer material and output an image signal, and a function to detect a jam of the transfer material. Characteristic transfer material detection device.