JPS6083053A - Automatic toner replenishing device - Google Patents

Abstract

PURPOSE:To maintain the density of printing constant surely by controlling replenishment of toner according to character dot signals and toner concentration signals. CONSTITUTION:A toner concentration sensor output A is a level signal that detects the toner concentration in a developing device directly or indirectly. Several kinds of values of threshold level B connected to a print density dial are set and the higher the concentration the higher the level selected. Signals of the two are inputted to a level comparator circuit 3. By providing a toner replenishing gate 4 that can pass the toner replenishing signal only when the toner concentration sensor output is smaller than the threshold level, presence/ absence instruction is given while watching the actual toner concentration, and thus, toner replenishing of high reliability is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a toner replenishing device for maintaining a constant print density in a dry electrophotographic Kanji printer or the like. .

[Prior art]

A conventional system of this type is shown in FIG. In the figure, (11 is a character dot counter, (21 is a circuit for matching the counter value specified by the print density dial (2) and this character dot counter 111.The operation will be explained next.

When printing with a kanji printer, it is common to display each character by dividing it into the presence or absence of dots, but this character dot signal is input to the character dot counter (11) and counted.On the other hand, the print density is determined by the operator. In order to have some degree of freedom in selection (2), a print density dial is set, and a certain value from this dial (2) is set in the matching circuit (2).
The character dot signal continues to be counted until it matches the output of the character dot counter (2).

The timing at which these two coincide is used as a toner replenishment signal to replenish a certain amount of toner into the developing machine.

At the same time, the counter value of dot counter il+ is set to Re5e.
t state (= return.

Note that the value set by the print density dial becomes smaller as the density becomes higher. That is, even if the number of dots is the same, the higher the density, the faster the toner replenishment signal is output.

An example of conventional toner replenishment uses the above method,
Since there is no feedback on the status of the printing process, there is a drawback that when the print density starts to get lighter, it tends to get lighter, and when it starts to get darker, it tends to get darker.

[Summary of the invention]

This invention was made to eliminate the above-mentioned drawbacks of the conventional printers, and its purpose is to reliably keep the print density constant by controlling toner replenishment using a toner density signal as well as a character dot signal. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Figure 2 (2, (3) shows the toner concentration sensor output (A
+ and the print density dial control several threshold levels (level comparison circuit with Bl, (4) is a level comparison circuit (toner replenishment gate that controls whether or not to pass the signal of the matching circuit (2) depending on the state of 31) It is.

In Figure 2, the toner density sensor output (A+ is a level signal that directly or indirectly detects the toner density in the developing machine. A value is set, and the higher the density, the higher the level is selected.

These (A+ and (B)) are input to the level comparison circuit (3).The conventional configuration passes the toner replenishment signal only when (A) < (Idl, that is, when the toner concentration sensor output is smaller than the threshold level. By installing a toner replenishment gate (4) that allows for toner replenishment, it is possible to issue a command for whether or not to replenish toner while monitoring the actual toner concentration.

Although the above embodiment does not describe a method for detecting an abnormality in the device, for example, a detection circuit is added that displays an error message in the case of Al2 (Bl) no matter how many times the toner replenishment signal of output 21 is received. This will make the method even more reliable.

〔Effect of the invention〕

As described above, according to this invention (2), highly reliable toner replenishment can be achieved because the toner replenishment method using the character dot count and the toner replenishment method using the toner density sensor are used together.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional toner replenishing device, and FIG. 2 is a block diagram of a toner replenishing device according to an embodiment of the present invention. fi+・Character dot counter, (2;...matching circuit,
(3)... Level comparison circuit, (41... Toner replenishment gate. In addition, the same reference numerals in the figure indicate the same - or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 212I Procedural amendment (voluntary) 21 Name of the invention: Automatic toner replenishing device 3. Relationship with the person making the amendment.
601,) Mitsubishi Electric Co., Ltd. Representative Katayuni Hachibe 4, Agent Address: 11213 Marunouchi-2-2, 111-ku Tocho-Dai, Totaku
5;. :, within Ryodenki Co., Ltd. 5. Subject of amendment (1) Claims of the specification, pattern of detailed explanation of the invention 6, Contents of amendment (1) Claims of the specification as shown in the attached sheet Correct. (2) The specification shall be amended as follows. 7. Catalog of appendix dimensions (1) Document indicating the scope of patent claims after correction 1 or more Claims Counting the number of dots of characters, etc. in toner replenishment devices such as kanji printers of dry electrophotographic devices and a density sensor that automatically detects the toner density level, and when the count value of the dot counter is above a predetermined value and the toner density level is below the predetermined density level, a toner replenishment finger signal is generated. An automatic toner replenishing device 1 characterized in that it outputs

Claims (1)

[Claims] A dot counter for counting dots M of characters, etc. in a toner replenishment device such as a kanji brileter of a dry type electrophotographic device;
Equipped with a density sensor that automatically detects toner density level.
An automatic toner replenishing device that outputs a toner replenishment instruction cooling signal when the count value of the dot counter reaches a predetermined value or more and the toner concentration level reaches a predetermined concentration level or less.