JP2784056B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus such as a copying machine.

(Prior Art) Conventionally, a latent image pattern or a visible image pattern is formed on a photoconductor by an image forming process such as charging, exposure, development, transfer, and cleaning, and a latent image potential or a visible image of the pattern is formed. The density is detected, the detection result (detection level) is fed back to each unit of the image forming process, and the charging potential, the writing light amount, the developing bias, the toner replenishment, the transfer potential, and the like are controlled so that an appropriate copy image is obtained. Alternatively, various image forming apparatuses configured to obtain a print image have been proposed.

(Problems to be Solved by the Invention) As described above, in an image forming apparatus of a type in which a pattern is formed on a photoreceptor, toner is supplied to the pattern portion. Consumption is increased.

Further, this pattern is often formed in a non-image forming area of a photoconductor in general. For this reason, the toner consumed by this pattern is collected as it is by the cleaning unit downstream of the transfer unit.

Therefore, in this type of image forming apparatus, when a pattern is formed for each image forming process and the original image is corrected in real time, the toner recovery tank of the cleaning unit becomes unnecessarily full. The frequency of replacing the tank and the toner supply cartridge is significantly increased.

For this reason, this type of image forming apparatus is generally configured to execute the pattern forming process every time the image forming process is executed a predetermined number of times, and to form a pattern at regular intervals.

However, when a pattern is formed at regular intervals in this way, it does not significantly affect non-immediate control such as toner replenishment. However, there is a problem that the change at the time of the correction becomes large and the accuracy of the image correction at the time of the image formation deteriorates.

As described above, in the conventional image forming apparatus, when a pattern is formed for each image formation, the accuracy of image correction at the time of image formation can be improved, but wasteful consumption of toner increases, and a certain interval is required. However, when a pattern is formed, wasteful consumption of toner can be suppressed, but on the other hand, there is a contradictory problem that image correction accuracy during image formation deteriorates.

On the other hand, in order to eliminate wasteful consumption of toner as described above, the toner collected by the cleaning unit is returned to the toner supply unit of the developing unit, and the toner consumed at the time of pattern formation is reused. A known image forming apparatus is also known.

However, the toner collected by this cleaning means contains impurities such as paper dust of transfer paper, and its properties have been changed by the transfer and separation chargers. Therefore, when this toner is reused, There is a problem that image deterioration and deterioration of development characteristics are induced.

Therefore, in practice, it is extremely difficult to suppress the toner consumption by the pattern in this way.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a latent image pattern or a visible image on a photoconductor by an image forming process such as charging, exposure, development, transfer, and cleaning. Forming a pattern, detecting a latent image potential or a visible image density of the pattern, and feeding back the detection result to each unit of the image forming process, in an image forming apparatus configured to obtain a proper image, A pattern toner cleaning unit for removing toner on the pattern from the photoreceptor is provided between each unit of the development process and the transfer process.

(Operation) According to the present invention, a pattern toner cleaning unit that removes toner on the pattern from the photoreceptor is provided between each unit of the development process and the transfer process. The toner is collected at a position before the transfer process is performed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the present invention comprises a charging unit 1, an exposure unit
2, known image forming means for executing an image forming process including latent image potential detecting means 3, developing means 4, visible image density detecting means 5, transfer means 6, separating means 7, cleaning means 8, etc. ,
The present invention is applied to an image forming apparatus arranged around the photosensitive member 9.

Here, the charging means 1, the transfer means 6, and the separating means 7 are constituted by scorotron chargers. Further, the latent image potential detecting means 3 is constituted by a surface potential sensor for measuring the surface potential of the photoconductor 9. Further, the developing means 4 includes a toner supply tank 41, a toner supply roller 42, a developing sleeve
43, and a stirring roller 44 and the like. Further, the visual image density detecting means 5 is constituted by a reflection type photo sensor for measuring the amount of reflected light from the photoconductor 9. Further, the cleaning means 8 includes a cleaning blade 81, a cleaning roller 82, a housing 83, and the like.

The image forming apparatus according to the present invention includes the developing unit 4 described above,
Pattern toner cleaning means between the transfer means 6
It is configured by installing 10.

The image forming process in this image forming apparatus is executed as follows.

That is, in FIG. 1, first, the surface of the photoconductor 9 is charged by the charging unit 1.

Next, prior to the formation of the electrostatic latent image of the document, the exposure unit 2 forms the latent image of the pattern A on the surface of the photoconductor 9. As a method of forming the pattern A, a pattern image formed in advance on a contact glass surface on which a document is placed is written on the photosensitive member 9 by an optical system including a mirror and a lens, or is stored in advance. Any method such as writing the pattern A directly on the photoconductor 9 by a laser beam may be used.

If the pattern A is in a non-image area of the photoconductor 9, a side end of the photoconductor 9 as shown in FIG.
It may be formed at any part between the image areas B at the center of the photoconductor 9 as shown in FIG.

Next, the photosensitive member 9 at the portion where the pattern A is formed
Is measured by the latent image potential detecting means 3.

Then, after the pattern A is visualized as a toner image by the developing means 4, the density is measured by the visual density detecting means 5.

As a result, the detection result (detection level) of the latent image potential or the visible image density of the pattern A is fed back to each unit of the image forming process, and the charging potential, writing light amount, developing bias, toner supply, and transfer of each process are performed. The potential and the like are controlled, and the image forming conditions of the document are set in advance so as to obtain an appropriate copy image or print image.

When the conditions of each image forming means are set in this way, a document image is formed on the photoreceptor 9 based on a well-known image forming process, and this document image is transferred onto transfer paper (not shown) by the transfer means 6. Transcribed. At this time, the toner remaining on the photoconductor 9 without being transferred to the transfer paper is removed from the photoconductor 9 by the cleaning unit 8.

On the other hand, the transfer paper is separated from the photoreceptor 9 by the separation means 7, then fixed by a fixing means (not shown), and discharged out of the apparatus.

By the way, the toner 20 that has visualized the pattern A is removed from the photoreceptor 9 by the pattern toner cleaning unit 10 prior to the formation of the above-described original image.

In the image forming apparatus according to the present embodiment, as shown in FIG. 2, a pattern A is always formed outside the image area B of the photoconductor 9, and the toner 20 of the pattern A is constantly cleaned by the pattern toner cleaning unit 10. It is configured as follows. Therefore, this image forming apparatus always detects the pattern A by the latent image potential detecting means 3 or the visible image density detecting means 5 to obtain the charging potential, writing light amount, developing bias, toner supply, transfer potential, etc. of each process. Can be corrected and controlled in real time, and the image forming conditions for development can be set so as to always obtain an appropriate copy image or print image.

Here, as shown in FIG. 3, when the method of forming the pattern A in the central portion between the image areas B of the photoconductor 9 is applied, only the toner 20 of the pattern A is removed. It is necessary to control the timing of the pattern toner cleaning means 10. The timing control of the pattern toner cleaning means 10 is performed, for example, as in this embodiment.
In a case where the toner 20 is removed by the blade 11 that is in pressure contact with the photoconductor 9, the blade 11 may be controlled so as to be in contact with or separated from the photoconductor 9. This type of pattern toner cleaning means 10 is suitable for correcting a document image for each sheet. Of course, this method can also be applied to a case where a document image is corrected for every plural sheets.

Further, since the pattern toner cleaning means 10 only needs to remove the toner 20 of the pattern A, it can be configured very small. Therefore, since the pattern cleaning means 10 has a small space occupancy, it does not adversely affect other image forming means when it is installed.

Further, in this embodiment, since the visible image density detecting means 5 is constituted by a reflection type photo sensor for measuring the amount of reflected light from the photoreceptor 9, the pattern toner cleaning means 10
The toner 20 of the pattern A is irradiated with light by the light source (LED) of the visual image density detecting means 5 at the upstream portion of the pattern A. Accordingly, the potential of the photoconductor 9 at the portion of the pattern A is sharply reduced at the upstream portion of the pattern toner cleaning means 10, and the electrostatic attraction of the toner 20 to the photoconductor 9 is significantly reduced.

As a result, the cleaning effect of the pattern toner cleaning unit 10 of this embodiment is greatly enhanced,
In addition, the toner recovery rate can be extremely increased.

Therefore, this pattern toner cleaning means 10
Even if a brush or a roller is used instead of the blade 11, the toner 20 can be collected very efficiently.

Further, since the pattern toner cleaning means 10 is installed at an upstream portion of the transfer means 6, the transfer means 6
Pattern A before being affected by corona discharge and transfer paper
Of the toner 20 can be collected.

Therefore, the toner 20 collected by the pattern toner cleaning means 10 can be reused as a toner for developing a document image because its characteristics are not deteriorated and impurities such as paper dust are not mixed.

Therefore, in the present embodiment, the toner conveying means 30 is provided, and the toner 20 collected by the pattern toner cleaning means 10 is returned to the toner supply tank 41 of the developing means 4.

As shown in FIG. 1, the toner conveying means 30 includes a toner conveying pipe 31 communicating the housing 12 of the pattern toner cleaning means 10 and a housing 45 of the toner replenishing tank 41, and a toner conveying pipe in the toner conveying pipe 31. And a toner transport coil 32 rotatably disposed along the path.

Therefore, the toner 20 collected by the pattern toner cleaning means 10 is transported along the toner transport path in the toner transport pipe 31 by rotating the pattern toner recovery square rod 13 and the toner transport coil 32 in FIG. Then, the toner is returned into the toner supply tank 41 of the developing unit 4 and is reused as the developing toner.

Here, the toner conveying means 30 may be formed separately from the housing 12 of the pattern toner cleaning means 10 and the housing 45 of the toner replenishing tank 41. Therefore, each joint can be simplified.

Here, the housing 46 of the developing means 4 and the latent image potential detecting means 3 and the housing 12 of the pattern toner cleaning means 10 and the visible image density detecting means 5 are also integrally formed, so that each detecting means 3 , 5 can be suppressed, so that their detection stability can be improved.

(Effects of the Invention) According to the present invention, the toner of the pattern can be collected without deterioration of the toner or contamination of impurities.
The toner can be reused. As a result, when this toner is reused, it is possible to prevent the image and the development characteristics from being induced.

Further, since the residual toner on the photosensitive member after the transfer process is only the amount corresponding to the original image, even when a pattern is formed for each image formation and image correction is executed in real time, wasteful consumption of toner is prevented. Can be suppressed.

Therefore, by practicing the present invention, the frequency of replacing the waste toner tank and the toner supply cartridge of the developing unit can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention, FIG. 2 is a schematic view showing a pattern formation site in the above embodiment, and FIG. 3 is a schematic diagram showing another formation site of the pattern. DESCRIPTION OF SYMBOLS 1 ... Charging means, 2 ... Exposure means, 3 ... Latent image potential detecting means, 4 ... Developing means, 5 ... Visible image density detecting means, 6 ... Transfer means, 7 ... Separating means, 8 ... ... Cleaning means, 9 ... Photoconductor, 10 ... Pattern toner cleaning means, 11 ... Blade, 20 ... Pattern toner, A ... Pattern, B ... Image area.

Claims (3)

(57) [Claims] A latent image pattern or a latent image pattern is formed on a photoreceptor by an image forming process such as charging, exposure, development, transfer, and cleaning, and the latent image potential or the latent image density of the pattern is determined. In the image forming apparatus configured to detect the detection result and feed back the detection result to each unit of the image forming process to obtain an appropriate image, the photosensitive member is disposed between each unit of the developing process and the transfer process. An image forming apparatus comprising a pattern toner cleaning unit for removing toner on the pattern from above. 2. An image forming apparatus according to claim 1, wherein the toner removed by said pattern toner cleaning means is returned to a developing means for executing said developing process. 3. An image forming apparatus according to claim 1, wherein a light elimination process of irradiating said pattern with light is performed before said pattern toner cleaning means.