JPH08314276A - Color image forming device - Google Patents

Abstract

PURPOSE: To prevent the mixing of a color without damaging equipment by electrically detecting that plural developing tanks are erroneously attached to a color image forming device main body. CONSTITUTION: Fixed resistances 5, 6, 7 and 18, 19, 20, 21 whose sizes are respectively different are provided at respective Y, M, C developing tanks 2, 3, 4 and the color image forming device main body 12. When the attaching positions of respective developing tanks are different because respective developing tanks and the fixed resistances on the side of a device main body are connected so as to be mutually in parallel, output voltage inputted in a control circuit 22 is different, so that it detects the erroneous attachment of the developing tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus for forming a color image by an electrophotographic method using developers of a plurality of colors, and more particularly, to a plurality of developing tanks for accommodating the developers. It is characterized by a structure for preventing erroneous mounting when it is mounted on.

[0002]

2. Description of the Related Art A color image forming apparatus that obtains a color image by using a charged image generally includes a developing tank containing yellow, magenta, cyan and black developers. These developing tanks are designed to be mounted at predetermined positions in terms of the structure of the device.
When you run out of developer and replace it with a new developer tank,
Be careful not to make a mistake in the mounting position. If the apparatus is operated with the developing tank erroneously attached, not only a desired color image cannot be drawn, but also developers of different colors mixed on the attachment portion side cannot be easily removed.

Therefore, conventionally, the structures of the fitting portions are made different from each other so that the developing tanks of the respective colors can be mounted only on the predetermined mounting portions, and mechanical erroneous mounting is prevented.

[0004]

However, in the above-described conventional configuration, when the developer tank is replaced in maintenance such as maintenance and inspection, the service person or the user has the developer tank and the mounting portion correspond to each other. Not realizing that there is no
If the developer tank is forcibly installed, the resin-molded fitting portion and the electrical connection terminal may be damaged.
Further, since the shape of the fitting portion is made different for each color developing tank, the cost becomes high.

Therefore, the present invention eliminates mechanical damage by electrically detecting erroneous mounting even if the developing tank and its mounting portion do not have different shapes.

[0006]

In order to solve the above-mentioned problems, a color image forming apparatus of the present invention provides a plurality of developing tanks having developers of different colors with resistors of different sizes. The color image forming apparatus main body to which the developing tank is mounted is provided with resistors of different sizes provided corresponding to the developing tank. When the developing tank is mounted to the apparatus main body, the resistance of the developing tank is set. It is characterized in that the resistor and the resistor on the apparatus main body side are connected in parallel.

[0007]

According to the above construction, since the resistances on the developing tank side are connected in parallel to the resistances on the main body side of the color image forming apparatus having different values, the combined resistance is the resistance value of the developing tank. And the combination with the resistance value on the main body side. For this reason, when the developing layer is erroneously mounted, a predetermined voltage value cannot be obtained, so that erroneous mounting of the developing tank can be detected.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a color image forming apparatus according to an embodiment of the present invention. In the figure, 1 is a black developing tank containing a black developer (hereinafter referred to as B
k developing tank), 2 is a cyan developing tank containing a cyan developer (hereinafter referred to as C developing tank), 3 is a magenta developing tank containing a magenta developer (hereinafter referred to as M developing tank).
Reference numeral 4 designates a yellow developing tank (hereinafter referred to as Y developing tank) containing a yellow developer.

These developing tanks are constructed so that they can be inserted into and removed from the main body 12 of the color image forming apparatus. When mounted on the main body 12 side, connection terminals 8, 9 for detecting the mounting of each developing tank are formed. 10 and 11 are connection terminals 1 on the device body 12 side.
It is possible to supply the developer from each developing tank to the apparatus main body 12 side while being connected to 3, 14, 15, and 16.

When the Bk developing tank 1 is attached to the apparatus main body 12, one of the connecting terminals 8 is connected to the power source (V
cc), the voltage value of which is connected to the control circuit 22.
Is input to The other of the connection terminals 8 is grounded.

The C developing tank 2, the M developing tank 3, and the Y developing tank 4 are provided with fixed resistors 5, 6, and 7 having different values. When each developing tank is attached to the main body 12 of the color image forming apparatus, the fixed resistors 18, 19 and 20 having different values provided corresponding to each developing tank are connected in parallel. The Y developing tank 4 side is connected to a power source (Vcc) via a fixed resistor 21, the divided voltage value is input to the control circuit 22, and the C developing tank 2 side is grounded.

The erroneous mounting detection operation of the color image forming apparatus of the present embodiment having the above-described structure will be described. In this embodiment, not only full-color printing but also monochrome printing is possible. Therefore, the size of the Bk developing tank 1 is made larger than other developing tanks to increase the capacity of the developer and The mechanism to detect the installation of the tank is separate. That is, in the case of monochrome printing,
It operates only when the Bk developing layer 1 is attached, and in the case of full-color printing, it operates only when all the developing tanks are attached.

Regarding whether or not the Bk developing tank 1 is installed, see B.
If the developing tank 1 is not installed, the control circuit 2
Since a high level signal is input to 2, the Bk developing tank 1 is determined not to be installed, and the Bk developing tank 1 is displayed on the display unit 23.
The information about unattached items is transmitted. On the other hand, when the Bk developing tank 1 is installed, a low-level signal is input to the control circuit 22, so it can be seen that the Bk developing tank 1 is installed.

Next, C developing tank 2, M developing tank 3, and Y developing tank 4
The detection of erroneous mounting will be described. For example, when all of C developing tank 2, M developing tank 3, and Y developing tank 4 are not installed,
As shown in the equivalent circuit of FIG. 2A, the resistors on the apparatus main body 12 side are connected in series, and the voltage level of the signal to the control circuit 22 is fixed resistors 18, 19, 2.
It is a value of resistance division composed of 0 and the fixed resistance 21.

In the circuit of FIG. 2A, the fixed resistor 1
The resistance ratio of 8, 19, 20, and 21 is 2: 1: (1/2):
When set to 1, the output voltage becomes (7/9) * Vcc, and V
When cc is 5V, the output voltage value is about 3.889V. The output level at this time is plotted at point A as shown in FIG.

Next, when the C developing tank 2, the M developing tank 3, and the Y developing tank 4 are all mounted at the proper positions, the developing tank-side fixed resistors 5, 6 and 7 and the apparatus main body 12 side. Fixed resistors 18, 19 and 20 are connected in parallel. This equivalent circuit is shown in FIG. In the circuit shown in the figure, the resistance ratio of the fixed resistors 5, 6, 7, 18, 19, 20, 21 is 1: (1/2) :( 1/4): 2: 1: (1/2): 1.
Then, the output voltage to the control circuit 22 is (7 /
13) ・ Vcc, and if Vcc is 5 V, it is about 2.6.
It becomes 92 V and is plotted at point B in FIG.

Next, at the mounting position of the M developing tank 3, the Y developing tank 4 is placed.
The case where the M developing tank 3 is erroneously mounted at the mounting position of the Y developing tank 4 will be described. The equivalent circuit in this case is shown in FIG.
The circuit configuration shown in FIG. When the output voltage to the control circuit 22 is calculated by the above resistance ratio, (67/12
7) ・ Vcc. When Vcc is 5 V, the voltage value is about 2.638 V, which is plotted at point C in FIG.

A case where only the Y developing tank 4 is not mounted and the remaining developing tanks are mounted at the corresponding mounting positions will be described. The equivalent circuit in this case has the circuit configuration shown in FIG. 2 (d), and the output voltage to the control circuit 22 is (3/5) · Vcc when calculated by the above resistance ratio.
Becomes When Vcc is 5V, the output voltage value is 3.00
It becomes 0 V and is plotted at point D in FIG.

FIG. 3 plots the output signal level to the control circuit 22 for the possible wearing situations.
It is a graph of it. The graph shows that if the developing tank is not installed, the value is from point B to less than point A, and if the developing tank is installed but the mounting position is wrong, the value is less than point B. Shows. Since the mounting state and the output signal level thereof correspond to each other on a one-to-one basis, it is possible to know from the output signal level which developing tank is not mounted or which developing tank is erroneously mounted. Therefore, the control circuit 22 controls the display unit 2 from the output signal level.
It is possible to display information about non-attachment or erroneous attachment on 3.

Regarding the resistance value of the fixed resistance provided in the developing tank and the main body of the color image forming apparatus, (1) fixed resistance 5> fixed resistance 6> fixed resistance 7 (2) fixed resistance 18> fixed resistance 19> fixed Resistance 20 (3) Fixed resistance 6 ≠ Fixed resistance 19 (4) Fixed resistance 7 ≠ Fixed resistance 20 If the four relations are satisfied, the mounting condition and its output signal level can be made to correspond one to one. .

[0021]

As described above, according to the present invention, it is possible to electrically detect the mounting status of the developing tanks of different colors and to warn the user when the mounting is wrong or not mounted. Therefore, it is possible to prevent the deterioration of the image quality due to the mixture of the developers of different colors, without mechanically damaging the device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram showing an electric circuit of the device.

FIG. 3 is an explanatory diagram of a developing tank detection operation of the apparatus.

[Explanation of symbols]

1 Black developing tank 2 Cyan developing tank 3 Magenta developing tank 4 Yellow developing tank 5,6,7,18,19,20,21 Fixed resistance 8,9,10,11,13,14,15,16 Connection terminal 12 Color Image forming apparatus main body 22 Control circuit 23 Display unit

Claims (1)

[Claims] 1. A plurality of developing tanks having developers of different colors are provided with resistors of different sizes, and a color image forming apparatus main body to which the developing tanks are mounted corresponds to the developing tanks. The resistance of the developing tank and the resistance of the apparatus main body side are connected in parallel when the developing tank is attached to the main body of the apparatus. Color image forming apparatus.