JP2000089553A - Method for detecting residual quantity of toner in image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting the residual quantity of toner in an image forming device by which the residual quantity of the toner can be more easily and accurately detected without using an optical sensor. SOLUTION: The image forming device is provided with a photoreceptor belt 1 on which the forming process of an electrostatic latent image, the developing process of a toner image 3c by a developing unit and the transfer process of a printing paper 7 are repeatedly executed in turn as a closed loop. Then, an image for detecting toner residual quantity 12 is developed in the area of the surface of the belt 1 which does not interfere with the image forming area thereof and read. Based on the density value thereof, the residual quantity of the toner 3a in the developing unit 3 is indirectly detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for an image forming apparatus for transferring a toner image to a printing sheet in a direction orthogonal to the direction of transport of the printing sheet, for example, so that the remaining amount of toner in a developing unit can be easily detected. It relates to a method for detecting the remaining amount.

[0002]

2. Description of the Related Art In recent years, toner-type image forming apparatuses capable of forming clear images with excellent resolution, such as laser printers, have become widespread. Among such toner-type image forming apparatuses, as proposed by the present applicant and filed and disclosed in Japanese Patent Application Laid-Open No. 9-230715,
The orthogonal transfer type image forming apparatus, which moves the toner image carrier in a direction perpendicular to the direction of transport of the printing paper and transfers the toner image in small increments one step at a time, is a structure that promotes miniaturization of products. Very suitable.

FIG. 3 is a schematic configuration diagram of a conventional orthogonal transfer type image forming apparatus, FIG. 4 is a perspective view showing a transfer process of the conventional orthogonal transfer type image forming apparatus, and FIG. 5 is a conventional orthogonal transfer type image forming apparatus. FIG. 5 is a schematic diagram showing a state of displacement of a toner image carrier of the image forming apparatus of the system.

In FIGS. 3 and 4, a photoreceptor belt 1 as an endless toner image carrier having a surface coated with a layer of an organic photoconductive material includes a transfer plate 10 on which a printing paper 7 is mounted. It is arranged in a position to cut through. The photosensitive belt 1 has a driving roller 1a whose position is fixed, a displacement roller 9 for changing the position up and down, and a transfer plate 10
Transfer opposing roller 8 that moves while rotating along the surface of
It is wound around. Around the photoreceptor belt 1, a charging device 2, a developing device 3 containing a toner 3a and a developing roller 3b, a cleaning device 4, a static eliminator 5, and an exposure device 6 for irradiating a laser are arranged. Have been. Further, a fixing device 11 for printing the transferred toner image is provided downstream of the printing paper 7 in the transport direction as shown in FIG.

When the photosensitive belt 1 travels in a direction perpendicular to the direction in which the printing paper 7 is conveyed, as shown by solid arrows in FIG. An electrostatic latent image is formed by the laser light from 6. When the toner 3a is pressed against the portion where the electrostatic latent image is formed by the developing roller 3b, a visible toner image 3c is formed on the toner image carrier 1.

After the formation of such a toner image 3c, FIG.
2, the transfer opposing roller 8 moves along the surface of the transfer plate 10 and presses the photosensitive belt 1 against the surface of the printing paper 7 on the transfer plate 10. At this time, the displacement roller 9 changes its position following the movement of the transfer opposing roller 8. That is, the transfer opposing roller 8 functions as a transfer roller and functions as a print head of a thermal transfer printer using an ink ribbon, while the displacement roller 9 is displaced left and right so that the photoreceptor belt 1 does not loosen. When the toner image 3c is formed on the photoreceptor belt 1, the position of the transfer opposing roller 8 is fixed to the position of the left end A in FIG. The toner image 3c is carried on the surface. Then, as shown in FIG. 5, the toner image 3c is transferred onto the printing paper 7 during one stroke in which the transfer opposing roller 8 moves in a direction to cut through the transfer plate 10.

During transfer to the printing paper 7, the feeding of the printing paper 7 is temporarily interrupted and stopped on the transfer plate 10, and the running of the photosensitive belt 1 is also stopped. And
The portion of the toner image carrier 1 where the toner image 3c is formed is
The photoconductor belt 1 is rubbed against the printing paper 7 by the transfer opposing roller 8 to displace the photosensitive belt 1 from the left end in the opposite direction by one step.
At the same time, a positive voltage is applied to the transfer plate 10 on which the printing paper 7 is placed, and the negatively charged toner image 3c is attracted from the surface of the toner image carrier 1 to be separated and transferred to the printing paper 7.

By the way, the photosensitive belt 1 is
When the toner image 3c is formed on the surface of the developing device 3, the toner 3a in the developing device 3 is consumed, and the amount of the toner 3a in the developing device 3 changes. Conventionally, a toner amount detecting device mainly using an optical sensor is used for detecting the amount of the toner 3a. That is, this toner amount detecting device has a window in a toner cartridge, and an optical sensor is disposed in this window to detect the presence or absence of toner.

[0009]

However, in the conventional toner amount detecting device, since the optical sensor is fixed only at one point of the window of the toner cartridge, it is possible to determine only the presence or absence of local toner near this window. For this reason, a plurality of optical sensors can be arranged at predetermined positions to accurately detect the amount of toner, but more optical sensors are required to detect the amount of toner with high accuracy. . Also, in the detection by the optical sensor, if the window on which the optical sensor is attached is contaminated with toner,
Actually, there is a possibility that the toner is erroneously detected as remaining even though the toner is not left.

An object of the present invention is to provide a method for detecting a remaining amount of toner in an image forming apparatus which can detect the remaining amount of toner more simply and with high accuracy without using an optical sensor.

[0011]

According to the present invention, there is provided a toner image carrier as a closed loop in which the steps of forming an electrostatic latent image, developing a toner image by a developing device, and transferring the toner image to a recording medium are sequentially performed. A method for detecting a remaining amount of toner in the developing device in the image forming apparatus, wherein an image for detecting a remaining amount of toner is developed in an area not interfering with an image forming area on a surface of the toner image carrier; The amount detection image is read, and the remaining amount of toner in the developing device is detected based on the density value.

According to the present invention, the amount of toner remaining in the developing unit can be easily known indirectly from the density value of the detection image formed directly on the toner image carrier without using an optical sensor or the like.

[0013]

According to the first aspect of the present invention, there is provided a toner image carrier in which the steps of forming an electrostatic latent image, developing a toner image by a developing device, and transferring the toner image to a recording medium are sequentially performed. A method for detecting the remaining amount of toner in the developing device in an image forming apparatus provided as a closed loop, wherein the toner remaining amount detection image is developed in an area that does not interfere with an image forming area on the surface of the toner image carrier, A toner remaining amount detecting method in an image forming apparatus, comprising: reading an image for detecting a remaining amount of toner and detecting a remaining amount of toner in the developing device based on a density value of the image. This has the effect that the remaining amount of toner can be detected steplessly.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a perspective view of a state of forming an image for detecting a remaining amount of toner according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a reading position of an image for detecting a remaining amount of toner according to the embodiment of the present invention. The configurations of the photoreceptor belt 1 and the developing machine 3 are the same as those of the related art shown in FIGS. 3 to 5, and the same components are designated by the same reference numerals.

As described in the background art, for example, the upper half of the closed loop in FIG. 2 is formed with an electrostatic latent image by the exposure unit 6 (see FIG. 3), and the photosensitive belt 1 runs. After passing through the developing device 3
c is formed. When the toner image 3c is aligned as a transfer image, the photosensitive belt 1 stops running, and the toner image 3c is transferred onto the printing paper 7 by the movement of the transfer opposing roller 8 as shown in FIG. .

As described above, it is essential to provide the photosensitive belt 1 with an area to which the toner image 3c is transferred, but it is possible to include an area not to be transferred to the printing paper 7. For example, if the distance between the drive roller 1a and the displacement roller 9 is set to be longer than the width of the printing paper 7, the portion deviating from the printing paper 7 can be used as an area unrelated to transfer. And in the present invention,
The surface of the photoreceptor belt 1 has a printing area 1 as shown in FIG.
The developing unit 2a and the remaining toner detection image 12 are developed separately. The drive roller 1a is provided with a reading unit 13 for reading the remaining toner detection image and detecting its density. This reading means 13 is, for example, CC
Any object that can detect the density of the target by the light reflectance such as D may be used.

The image 12 for detecting the remaining amount of toner is formed in an area not interfering with the original image forming area, that is, the printing area 12a and not transferred to the printing paper 7 at the time of transfer.
To form an electrostatic latent image, and the developed image is developed by the developing device 3 as a black image having a fixed width.

On the other hand, when the remaining amount of the toner 3a in the developing unit 3 is sufficient, the density of the remaining toner detecting image 12 becomes substantially constant unless there is a change in environment or bias. When the remaining amount of the toner 3a becomes small, the image 1 for toner remaining amount detection
The density of No. 2 becomes lighter, or unevenness appears in each part. Therefore, if the image for toner remaining amount detection 12 is read by the reading means 13 and this read image is converted into a density value and output, the remaining amount of the toner 3a can be indirectly known from the density value.

As described above, since the photoreceptor belt 1 goes around the process from the formation of the electrostatic latent image to the development and the transfer to the printing paper 7, the reading is performed only at one place where the photoreceptor belt 1 passes. As long as the means 13 is provided, the remaining amount of the toner 3a in the developing device 3 can be detected from the toner remaining amount detection image 12. Therefore, unlike the related art, a plurality of optical sensors are not required, and the detection accuracy does not decrease even if there is a stain due to toner adhesion.

The image 12 for detecting the remaining amount of toner may be executed every time the image is developed. However, in order to suppress the consumption of the toner 3a, the image is executed only in the final transfer step for one print sheet 7. It is preferable to do so. That is, in the orthogonal transfer method, the transfer is performed while changing the position of the printing paper 7 repeatedly (about three to four times) corresponding to the width of the photoreceptor belt 1, so that the toner remaining amount detection image is obtained only at the last transfer. If 12 is developed, its consumption can be reduced.

[0021]

According to the present invention, an image for detecting the remaining amount of toner is formed directly on the toner image carrier, and is read to indirectly determine the remaining amount of toner in the developing device from its density value. When the toner image carrier is actually operated, the remaining amount of toner can be simultaneously detected. Accordingly, it is possible to reliably know the remaining amount of toner in accordance with the operation of the image forming apparatus, and to eliminate the possibility of erroneous detection due to toner adhesion as in the case of using an optical sensor as in the related art.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image forming state for detecting a remaining amount of toner according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a reading position of a toner remaining amount detection image according to the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional orthogonal transfer type image forming apparatus.

FIG. 4 is a perspective view showing a transfer process of a conventional orthogonal transfer type image forming apparatus.

FIG. 5 is a schematic diagram showing a state of displacement of a toner image carrier of a conventional orthogonal transfer type image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoreceptor belt (toner image carrier) 1 a drive roller 2 charger 3 developing device 3 a toner 3 b developing roller 3 c toner image 4 cleaning device 5 static eliminator 6 exposing device 7 printing paper 8 transfer facing roller 9 displacement roller 10 transfer plate 11 Fixing device 12 Toner remaining amount detection image 12a Printing area 13 Reading means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Uemura 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Masanori Shibata 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Teruo Mitsui 1006 Odaka, Kazuma Kadoma, Osaka Pref. 1006 Kadoma, Kadoma Matsushita Electric Industrial Co., Ltd. (72) Koji Umeno, inventor, Koji 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term in Sangyo Co., Ltd. (reference) 2H077 DA03 DA15 DA47 DA63

Claims (1)

[Claims] An image forming apparatus including, as a closed loop, a toner image carrier that repeats a process of forming an electrostatic latent image, developing a toner image by a developing device, and transferring the toner image to a recording medium in order; A method for detecting the remaining amount of toner, comprising developing a toner remaining amount detection image in an area not interfering with an image forming area on the surface of the toner image carrier, reading the toner remaining amount detection image, A method for detecting a remaining amount of toner in the image forming apparatus, wherein the remaining amount of toner in the developing device is detected based on a density value.