JPS6057873A - Toner density controlling method - Google Patents

Abstract

PURPOSE:To improve copy quality and prolong the life of a toner supplementing member by adjusting the once supplementary amount of toner to a value suitable for consumption. CONSTITUTION:A CPU9 detects the starting point of development of each primary color to turn on a multiplexer 7, and receives toner density signals from respective oscillators 6Y, 6M and 6C on time division basis, one after another, to output a toner supplement signal when the density is lower than a set value. This toner supplement signal drives the toner supplementing member for a time T to supply a minimum unit amount of toner, and the toner supplement signal outputted during copying operation is counted simultaneously to measure its frequency of generation. If the toner consumption is very large, the counted value increases. Then when the counted value attains to ''3'', the operaton time of the toner supplementing member is extended double to 2T, and when the counted value increases up to ''5'', the operation time is set to 3T, i.e. full operation, thereby supplying toner suitably for the consumption.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a toner control method for an electrophotographic apparatus.

(Prior art) Toner e-degree control in electrophotographic devices that use a two-component developer consisting of toner and carrier uses an inductance type detector that takes advantage of the fact that magnetic permeability changes when toner concentration changes. This is done by generating a signal from the source to operate a toner replenishing member and replenishing a certain amount of toner.

For this reason, in the case of originals with low toner consumption, the toner density may be maintained at the upper limit for a long period of time, causing toner scattering, or the g-adhesion with the carrier may be insufficient, resulting in poor copy quality. In addition, in the case of a solid document that consumes a large amount of toner, it is necessary to replenish the toner without interruption.2) There is a problem that the life of the toner replenishing member is shortened.

(Purpose) In view of these problems, the present invention aims to improve copy quality and extend the life of a toner replenishing member by adjusting the amount of toner replenished at one time to tψ commensurate with the consumption amount. The purpose of this study is to propose a method for controlling toner density.

That is, the feature of the present invention is that one toner replenishment 3111k/7 is performed in proportion to the frequency of the toner replenishment signal.
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FIG. 1 is a cross-sectional view showing a developing section of a color electrophotographic apparatus to which the present invention is applied, and symbols IY, IM, and Ic are shown in the figure.
These are three color developing tanks containing yellow, magenta, and cyan toners, respectively, and developing sleeves 3Y and 3M that are disposed around the photosensitive tram 2 and close to the photosensitive drum 2.

Toner density detectors 5Y, 5M, and 5C are installed below separators 4Y, 4M, and 4C in contact with 3C to detect toner density as changes in intufftance. It is configured to develop according to the order.

Fig. 2 is a block diagram showing an example of a device used for one-shot ψ1, and symbols 6Y, 6M, and 6C on the right in the middle of 1Δ indicate detectors 5Y, 5M, and 5C installed in each developing tank. This is an LC oscillator serving as a conductance element, and is configured to time-divisionally output an oscillation frequency signal proportional to the toner concentration of the developer to data 7 and hess 8 via a multiplexer 7 controlled by a CPU 9, which will be described later. . 9 is the aforementioned CPU that detects the developing process of each developing tank, and for each color development, the toner density signal is captured at the start of development for the first copy, and for the second copy. Thereafter, the multiplexer 7 is controlled ON-OFF by using the time when the developing process is completed as the capturing timing, and the captured signal is compared with the set value to generate a toner replenishment signal in each developing process when the toner concentration is low. However, the toner replenishing member is configured to output a signal that determines the operating time of the toner replenishing member depending on the frequency of this.

Next, the operation of the apparatus configured as described above will be explained based on the flowchart shown in FIG.

When the copy button is pressed now, the CPU 9 detects this, turns off the multiplexer 7, and turns off the LC oscillator 6Y.
, 6M, and 6C (prevents input to the CPU 9), starts copying operation f1: for the first sheet, and starts developing with numbers 1110 for yellow, magenta, and cyan.This causes each developing tank to IY, IM, LC sleeve 3Y
, 3M, and 3C via separators 4Y, 4M, and 4C to toner concentration detectors 5Y, 5M, and C, and a heap of toner is detected in five parts of the detector (Fig. 1). It begins to flow smoothly in the channel of the vessel.

The CPU 9 determines the development start points sy, Sm, and Sc for each color.
4), the multiplexer 7 is turned on and the toner concentration signals from each oscillator 6Y, 6M, 6C are captured one after another by time division.

The CPU 9 compares the captured toner concentration signals of each color with the set value, and outputs an I/toner replenishment signal if the toner density of the developer is lower than the set value. This toner replenishment signal is used to replenish the minimum unit amount of toner by driving the toner replenishment member for a time T as shown in FIG. , its frequency of occurrence is measured. At this time, if the image occupancy rate of the document is high and toner consumption is large, replenish toner. In this way, when the count value reaches r3J, the operating time of the toner supply member is doubled to 2T.
), and when the count value reaches "5", the operation time is increased to 3.
T, that is, it operates at full capacity and replenishes toner one after another in proportion to the consumed amount (m). When the first copy is completed in this manner, the 81 value is checked, and if it is rlJ, it is stored, and otherwise it is cleared. Subsequently, when copying the second and subsequent sheets, the CPU 9 detects the points Ey, Em, and Ec at which the developing process is completed, and turns on the multiplexer 7 at each of these points. When the toner replenishment signal is output at this point, the toner replenishment amount is determined by adding it to the number 4fi stored in the previous copying process.
Furthermore, when no toner replenishment signal is output, the count value is cleared and counting starts from the beginning. This makes it possible to always replenish I-toner in an amount commensurate with the amount of toner consumed.

In this embodiment, the amount of toner replenishment at one time is divided into three stages, but in the second stage or fourth stage embodiment,
Although the description has been made by taking an example of a color copy using three primary colors, it goes without saying that the present invention can be similarly applied to a monochrome electrophotographic apparatus using black toner.

(Effects) Second, as explained above, according to the present invention, one i-toner replenishment hY is determined in proportion to the frequency of occurrence of the toner replenishment signal. Not only can high-quality copies be obtained without causing excess or deficiency of toner in the developing tank, but also the frequency of starting and stopping of the toner replenishing member can be reduced to extend the life of the toner replenishing member. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus showing an example of a color development position apparatus to which the present invention is applied, FIG. 2 is a configuration 1 showing an example of an apparatus used for wood production, and FIG. FIGS. 4 and 51A are a flowchart showing the operation of the apparatus, a timing chart showing the operation of the same apparatus, and an explanatory diagram showing the toner replenishment operation. 1Y, IM, IC...Developing tank 2...Photoconductor drum 5Y, 5M, 5C...Toner concentration detector Applicant Ricoh Co., Ltd. Agent Patent attorney Kei Nishikawa Katsuhiko Kimura

Claims (1)

[Claims] Detects the toner concentration in the developer tank and compares it with the set value.
a step of outputting a toner replenishment signal when the setting is less than or equal to 1α, determining the frequency of the toner replenishment signal], and a step of determining a single operation time of the toner replenishment member in proportion to the frequency. Toner concentration control method.