JPH02207281A - Electrophotographic copying device - Google Patents

Abstract

PURPOSE:To find the faulty supply of toner even before actually performing printing and to prevent faulty printing from occurring by providing a detection means for photically detecting the faulty adhesion of a toner layer on the circumferential surface of a developing roller. CONSTITUTION:A doctor blade 20 which is a toner layer thickness regulating member is fixed to a rotary shaft 21 and supported so as to be freely rocked. The detection means for photically detecting the faulty adhesion of the toner layer on the circumferential surface of the developing roller 6 between the toner layer thickness regulating member 20 and a photosensitive drum 9 is provided. Namely, a part from the downside of the doctor blade 20 on the circumferential surface of the developing sleeve 6 to the photosensitive drum 9 is scanned with detecting light 34 projected from a light scanning device 33 and reflected detection light 34' is detected by a photosensor 40, then the faulty adhesion of the toner 10 is detected by detecting the scattering of the light. Thus, the faulty supply of the toner is found out even before actually performing printing and the faulty printing is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention develops an electrostatic latent image formed on a photosensitive drum by optical scanning of an image scanning device with toner supplied from a developing device, and converts this toner image into a The present invention relates to an electrophotographic device that performs printing by transferring onto paper.

2. Description of the Related Art In general, a developing device of an electrophotographic apparatus has a developing roller and a toner layer thickness regulating member opposing the developing roller attached to an opening of the developing device main body, and the amount of toner supplied by the developing roller is controlled by the toner layer. Printing quality is kept high by controlling the thickness to an appropriate value using a thickness regulating member. However, the distance between this toner layer thickness regulating member and the developing roller is about 0.2 to 1. O (mm)
Because it is extremely narrow, foreign objects such as lint and solidified toner lumps may get caught here. In this case, the toner from the clogged part does not adhere well to the developing roller, resulting in white lines and density unevenness in the sub-scanning direction on the image.

Utility Model Application No. 63101 was developed as a solution to these problems.
A developing device disclosed in Japanese Patent No. 958 can be considered.

Therefore, this apparatus will be described as a conventional example of an electrophotographic apparatus with reference to FIG. In the developing device 1 of this electrophotographic apparatus, a doctor blade 4, which is a toner layer thickness regulating member, is attached to the upper edge of an opening 3 formed at the lower front of a housing 2, which is a main body of the developing device. Therefore, a developing sleeve 6, which is a developing roller having a built-in magnet roller 5 having a plurality of magnetic poles, is attached so as to substantially close the opening 3 to which the doctor blade 4 is attached. In this developing device 1, a partition plate 7 forming an acute angle O with a tangent to the developing sleeve 6 is connected to the housing 2.
The developing sleeve 6 is integrally formed inside the developing sleeve 6 and is disposed opposite to the developing sleeve 6.

Furthermore, a blade-shaped stirring member 8 is disposed inside the housing 2 behind the partition plate 7.

The developing device 1 is disposed in an electrophotographic apparatus with the developing sleeve 6 in close proximity to the photosensitive drum 9, as shown in the figure, and the housing 2 contains toner.
has been introduced.

In such a configuration, in the developing device 1 of this electrophotographic apparatus, when the photosensitive drum 9 rotates due to the operation of a device, the developing sleeve 6 of the developing device 1 rotates in synchronization with this rotation.
rotates, and the toner 10 is supplied to the photosensitive drum 9. At this time, the developing sleeve 6 is attracted by the magnetic roller 5.
The toner 10 adhering to the circumferential surface of the toner 10 is regulated in two stages by the partition plate 7 and the doctor blade 4 and is made uniform. Note that since the housing 2 of this developing device 1 has a horizontally elongated shape, the toner 10 is constantly stirred by the stirring member 8 so that the toner 10 does not remain behind the housing 2.

Problem to be Solved by the Invention In the developing device 1, which is a dual-unit type, the toner 10 adhering to the developing sleeve 6 is regulated in two stages to reduce the probability that foreign matter will be caught in the gap between the doctor blade 4 and the developing sleeve 6. is lowered. However, foreign matter may still become clogged, and this foreign matter clogging is discovered after printing is actually performed and a printing defect occurs, resulting in a need to reprint and delaying the work. Furthermore, there is a possibility that various types of damage may occur in the developing device 1 that is driven with foreign matter trapped therein. Moreover, in order to remove foreign matter, it is necessary to remove the developing device 1 from the electrophotographic apparatus and disassemble it for cleaning, which is a complicated operation. Therefore, the practicality and reliability of the electrophotographic apparatus is reduced.

Means for Solving the Problems An image scanning device and a developing device are arranged facing the photosensitive drum in sequence, and a developing roller is arranged close to the photosensitive drum at the opening of the developing device, and the developing roller is opposed from the - side. A toner layer thickness regulating member is provided, and a detection means is provided for optically detecting adhesion failure of the toner layer on the peripheral surface of the developing roller from the toner layer thickness regulating member to the photosensitive drum.

By providing a detection means that optically detects adhesion failure of the 1st layer on the peripheral surface of the developing roller from the toner layer thickness regulating member to the photosensitive drum, toner supply failures can be detected even before actual printing. can.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. Note that the same parts as those of the developing device tl illustrated in FIG. 5 are given the same names and symbols, and description thereof will be omitted.

In this electrophotographic apparatus 11, on the circumferential surface of the photosensitive drum 9,
Image scanning device 12, developing device 13, transfer charger 14
, a toner cleaner 15, a static elimination lamp 16, a charger 1, etc. are arranged facing each other in order, and a paper conveyance path (not shown) is formed between the photosensitive drum 9 and the transfer charger 14.

Therefore, the structure of the developing device 13 will be explained.

A doctor blade 20, which is a toner layer thickness regulating member, located at the edge of the opening 19 of the housing 18, which is the main body of the developing device, is attached to a rotating shaft 21, which is a toner layer thickness regulating member supporting means.
It is fixed to and swingably supported. Further, a cleaning blade 22 pivotally supported in a swingable manner at the lower front part of the housing 18 facing the developing sleeve 6 is mounted on the M
It is connected by a rod 24 to a support member 23 attached to the back side of the doctor blade 20 described in j. Incidentally, an inclined surface 25 is formed at the front of the second part of the housing 18, on which the supporting member 23 rotated together with the doctor blade 20 comes into contact, and a receiving tray is formed at the lower front so as to be continuous with the distal end of the cleaning blade 22. 26 is installed.

Further, the image scanning device 12 includes, within the housing 27,
A polygon mirror 29 directly connected to a scanner motor 28 is disposed on the optical axis of a laser diode (not shown).
A reflection mirror 32 is arranged on the reflection optical axis of the polygon mirror 29 to reflect the scanning light 30 through an opening 31 toward the photosensitive drum 80.

In this electrophotographic apparatus 11, an optical scanning device 33 is disposed above and in front of the image scanning device 12 marked -1-. Note that, like the image scanning device 12, this optical scanning device 33 includes a laser diode (not shown), a scanner motor 36, and a polygon mirror 3 in a housing 35.
7. It has a structure in which a reflecting mirror 38 and the like are provided. Further, in front of the opening 39 that emits the detection light 34, an optical sensor 4 that receives the reflected detection light 34' from the developing sleeve 6 is provided.
0 is provided, and this optical sensor 40 and the optical scanning device 33 form a detection means.

In such a configuration, this electrophotographic apparatus 11 has the following features:
The photosensitive drum 9 charged by the discharging action of the charger 17 is irradiated with scanning light from the image scanning device 12 to form an electrostatic latent image, and this electrostatic latent image is developed with the toner 10 supplied from the developing device 13. be done. The toner image thus formed is transferred onto the paper by the transfer charger 14, and is further heated, etc., to complete printing. On the other hand, the toner 10 remaining on the circumferential surface of the photosensitive drum 9 after the transfer is completed is removed by the toner cleaner 15, and the static elimination lamp 1
After being uniformly neutralized by the charger 6, it is charged again by the charger 17 in preparation for the next printing.

During double printing, in this developing device 13, the portion of the circumferential surface of the developing sleeve 6 from below the doctor blade 20 to the photosensitive drum 9 is scanned by the detection light 34 emitted from the optical scanning device 33. , reflected detection light 34' is detected by the optical sensor 40. As illustrated in FIG. 2(a), when the toner 10 is well supplied,
As illustrated in FIG. 2 (1)), the detection value of the optical sensor 40 maintains a constant low output.

On the other hand, as illustrated in FIG. 3(a), when a foreign object 41 is caught in the gap between the doctor blade 20 and the developing sleeve 6, the toner 10 is not supplied from this part and the circumferential surface of the developing sleeve 6 is When this portion is scanned, the detection value of the optical sensor 40 shows a high output as illustrated in FIG. 3(b). This defective adhesion of the toner 10 is detected by detecting light scattering, similar to a barcode scanner, and is notified to the operator (not shown) by lighting an indicator lamp (not shown), etc. .

Therefore, this operator rotates the doctor blade 20 via the rotating shaft 21 to widen the gap between the doctor blade 20 and the developing sleeve 6, and also pulls the cleaning blade 22 with the rod 24 to apply it to the circumferential surface of the developing sleeve 6. bring it into contact. By operating the developing device 13 under this condition, the foreign matter 41 is pulled out of the developing device 13 by the rotating developing sleeve 6, removed from the circumferential surface of the developing sleeve 6 by the cleaning blade 22, and discharged into the receiving tray 26. be done. At this time, if the distance between the doctor blade 20 and the developing sleeve 6 is less than the appropriate value, printing can be performed. After removing the foreign matter 41,
The doctor blade 20 is returned to its original position and the distance between it and the developing sleeve 6 becomes an appropriate value, and the cleaning blade 22 is separated from the circumferential surface of the developing sleeve 6.

That is, in this developing device 13, the foreign matter 41 attached to the developing sleeve 6, which is normally difficult to remove, can be quickly and easily removed without disassembling the device. There is no possibility that the developer will be caught up in the developing sleeve 6 and returned to the developing device 13 again. Furthermore, by monitoring the output value of the optical sensor 40 again, it can be confirmed whether the foreign matter 41 has been reliably removed. Furthermore, optical sensor 4
It is also conceivable to connect a motor to the doctor blade 20 via a detection device or a driver, and to connect this motor to the rotating shaft 21 of the doctor blade 20 to automate the removal work of the foreign matter 41.

Note that in the electrophotographic apparatus 11 of this embodiment, a combination of the optical scanning device 33 and the optical sensor 40 is illustrated as a detection means for detecting insufficient supply of toner on the developing sleeve 6, but the present invention is not limited to this. It is not limited to this, and it is also possible to use a line sensor or the like.

Next, a second embodiment of the present invention will be described based on FIG. 4. This electrophotographic device 42 has an optical sensor 40 attached in front of the opening 31 of the image scanning device 12, and a swingable optical path changing mirror 43 serving as an optical path changing means on the optical path from the image scanning device 12 to the photosensitive drum 9. is provided.

Note that the other structure is similar to that of the electrophotographic apparatus 11 described above.

In such a configuration, this electrophotographic apparatus 42 has the following features:
During printing, the optical path changing mirror 43 is held at the rear, and the scanning light 30 of the image scanning device 12 is irradiated onto the photosensitive drum 9. Then, printing is performed in the same manner as in the electrophotographic apparatus 11 described above.

In this electrophotographic apparatus 42, the optical path changing mirror 43 is swung to move the optical path from the image scanning device 12 to the photosensitive drum 9 when the device is started, or when one printing is completed and paper is conveyed in preparation for the next printing. The scanning light 30 is reflected toward the developing sleeve 6. Therefore, the toner supply failure is detected in the same manner as in the electrophotographic apparatus 11 described above, and the foreign matter 41 is removed.

Effects of the Invention The present invention provides detection means for optically detecting adhesion failure of the toner layer on the circumferential surface of the developing roller from the toner layer thickness regulating member to the photosensitive drum in a double series. Since toner supply defects can be detected even before the toner supply is performed, it is possible to prevent the occurrence of printing defects.Moreover, the scanning light emitted from the image scanning device is bent to reach the photosensitive drum from the toner layer thickness regulating member. By providing an optical path changing means for irradiating onto the developing roller circumferential surface and providing an optical sensor that detects reflected light from the developing roller circumferential surface, a foreign object detection mechanism can be formed without adding a new optical scanning device. In addition, by providing a toner layer thickness regulating member support means that displaceably supports the toner layer thickness regulating member and widening the distance between the toner layer thickness regulating member and the developing roller, the toner layer thickness regulating member and the developing roller can be separated. Foreign matter caught in the gap can be easily removed without disassembling the developing device, and an electrophotographic device with high practicality and reliability can be obtained.

21... Toner layer thickness regulating member support means, 30°/light,
33... Optical scanning device, 40... Optical sensor, Optical path changing means Tokyo Electric Co., Ltd.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are explanatory diagrams of the operating state showing the first embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of the light detection state, and FIGS. 4(a,), (b) is a vertical side view of the second embodiment, and FIG. 5 is a vertical side view of the conventional example.

Claims (1)

[Scope of Claims] 1. An image scanning device and a developing device are sequentially arranged opposite to a photosensitive drum, and a developing roller is arranged close to the photosensitive drum at an opening of the developing device and faces the developing roller from above. An electrophotographic apparatus comprising: a toner layer thickness regulating member; and a detection means for optically detecting adhesion failure of the toner layer on the circumferential surface of the developing roller extending from the toner layer thickness regulating member to the photosensitive drum. . 2. A claim characterized in that an optical scanning device that optically scans the circumferential surface of the developing roller from the toner layer thickness regulating member to the photosensitive drum is provided, and an optical sensor that detects reflected light from the circumferential surface of the developing roller is provided. Item 1. The electrophotographic device according to item 1. 3. An optical path changing means is provided to bend the scanning light emitted from the image scanning device and irradiate it onto the circumferential surface of the developing roller from the toner layer thickness regulating member to the photosensitive drum, and detect the reflected light from the circumferential surface of the developing roller. 2. The electrophotographic apparatus according to claim 1, further comprising a photosensor for detecting an image. 4. Claim 1, further comprising a toner layer thickness regulating member support means for movably supporting the toner layer thickness regulating member and increasing the distance between the toner layer thickness regulating member and the developing roller.
3. The electrophotographic apparatus according to 2 or 3.